Philips O Akinwole, Amerti Guta, Madeline Draper et al.

Research Square • 2021

Abstract The effluents of wastewater treatment plants (WWTPs) represent a complex mixture of nutrients and toxic substances, thus, the potential exists for the effluents to significantly impact the biochemical characteristics and bacterial communities of the receiving water. We examined spatial and seasonal patterns, and the impact of effluents on microbial biomass, bacterial community structure, and metabolic diversity on a fourth-order stream. We took triplicate sediment samples at five different locations along a 5,000m transect over three sampling periods. We quantified bacterial community structure as community-level physiological profiles and biomass with phospholipid phosphate analysis. Our findings highlight the worrisome impacts of effluents on microbial biomass and bacterial metabolic diversity on the receiving water. Microbial biomass was significantly higher at the WWTP outfall compared to upstream and downstream sites and correlated positively with sediment physicochemical parameters. Furthermore, our data revealed significant spatial differences in bacterial community structure in the context of WWTP impact. High nutrient availability (lower carbon/nitrogen ratios) at the outfall increased site-specific bacterial metabolic diversity in winter but decreased the same in fall. Seasonal changes in the sedimentary microbial biomass and bacterial carbon substrate utilization were evident regardless of the spatial variations or impacts of the wastewater effluents. Communities in fall showed more versatile substrate utilization patterns than the winter communities. These results suggest that WWTP effluents significantly increased microbial biomass and highlight its mixed effects on bacterial community structure and metabolic diversity. Also, our data underscore a close association between sedimentary physicochemical parameters and the associated microbial functional activities.

Nilesh Sonune, Anil Garode

Current World Environment • 2015

The potential of bacteria for the treatment of municipal wastewater was investigated in present study. Total eight bacterial isolates were used for this study that showed growth on wastewater agar medium. These isolates were identified on the basis of morphological and biochemical test and identified as Bacillus licheniformis NW16, Pseudomonas aeruginosa NS19, Pseudomonas sp. NS20, Planococcus salinarum NS23, Stenotrophomonas maltophilia NS21, Paenibacillus sp. NW9, Paenibacillus borealis NS3 and Aeromonas hydrophilia NS17. The B. licheniformis NW16 showed highest potential to reduce all parameter under study than other isolates except Ammonical nitrogen. B. licheniformis NW16 and Aeromonas hydrophilia NS17 showed maximum reduction (42.86%) in BOD each. B. licheniformis NW16 and Paenibacillus sp. NW9 showed 82.76% and 81.61% reduction in COD respectively. B. licheniformis NW16, P. salinarum NS23 and Aeromonas hydrophilia NS17 showed reduction in nitrate ranging from 17.36%-63.64%. All the isolates have potential to reduced phosphate from 17.55% -72.3%. B. licheniformis NW16, Ps. aeruginosa NS19, Pseudomonas sp. NS20, Paenibacillus sp. NW9 and Aeromonas hydrophilia NS17 showed reduction in TSS ranging from 42.69%-79.94%. B. licheniformis NW16, Ps. aeruginosa NS19, Pseudomonas sp. NS20, S. maltophilia NS21 and Paenibacillus sp. NW9 showed reduction in TDS ranging from 14%-81.4%.

Luz Chacon, Keilor Rojas-Jimenez, Maria Arias-Andres

bioRxiv (Cold Spring Harbor Laboratory) • 2023

Abstract Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) widely used as the active ingredient of disinfectants. Its excessive discharge in wastewater is constant and in high concentrations, likely affecting the physiology of microbial communities. We compared the community physiological profile of activated sludge bacteria with and without in vitro previous exposure to a high concentration of BAC (10 mg/L). We measured the community functional diversity (FD), carbon substrate multifunctionality (MF), and the median effective concentration that inhibits carbon respiration (EC 50 ) using Biolog® EcoPlatesTM supplemented with a gradient of 0 to 50 mg/L of BAC. Surprisingly, we did not find significant differences in the physiological parameters between treatments. Certain abundant bacteria, including Pseudomonas, could explain the community’s tolerance to high concentrations of BAC. We suggest that bacterial communities in wastewater treatment facilities’ activated sludge (AS) are “naturally” adapted to BAC due to frequent and high-dose exposure. We highlight the need to understand better the effects of QACs in wastewater, their impact on the selection of tolerant groups, and the alteration in community metabolic profiles.

Manjiri Patil, Pranav Kshirsagar, Prashant Dhakephalkar et al.

Research Square • 2025

Abstract The dairy industry generates wastewater characterized by organic components, predominantly composed of proteins and fats, which can be effectively treated through biological processes. The present study aimed to develop a bacterial consortium for bioaugmentation to enhance the treatment of simulated dairy wastewater. A total of 75 bacterial isolates were obtained using Direct Isolation (DI) and Enrichment Isolation (EI) methods. Among these, four strains exhibiting the highest proteolytic and lipolytic activities within 24 hours were selected for further investigation. The isolates were screened based on their extracellular enzyme activities (proteinase and lipase), as well as their maximum lipolytic (0.3–0.7 mm/h) and proteolytic activity (0.67–0.83 mm/h) by a novel approach of rate of diffusion on Tributyrin Agar (TA) and Modified Skimmed Milk Agar (MSMA), respectively. The selected strains were identified by 16S rRNA gene sequencing as Massilia haematophila (DSSC1) , Brevibacillus agri (ENAT1) , Pseudomonas guguanensis (ENOG5) , and Lysinibacillus fusiformis (ETOG2 ) . The biodegradation potential of individual strains and their consortium was assessed through Chemical Oxygen Demand (COD) reduction in simulated dairy wastewater. The individual bacterial strains achieved COD reductions from an initial concentration of 3815 mg/L to 2950, 2813, 2480, and 2893 mg/L. In contrast, bioaugmentation with the bacterial consortia reduced COD to 2190 mg/L, resulting in a 26–86% higher reduction compared to the individual strains. This study presents the first report on the use of a novel approach of diffusion-based assay to develop an effective and innovative bacterial consortium for efficient dairy wastewater treatment. These findings highlight the potential of this approach towards enhancing biodegradation efficiency and advancing sustainable wastewater management practice.

Hossam Abdel Rahman

• 2021

The activated sludge process in Wastewater Treatment Plant (WWTPs) relies on the activities of microbes to reduce the organic and inorganic matter and produce effluent that is safe to discharge into receiving waters. This research examined the effects of non-steroidal antiinflammatory drug (NSAID) ibuprofen and the antibiotic tetracycline on the microbial population in activated sludge from the Humber WWTP. The current investigation was designated to observe the impact of these contaminants, at low (environmentally relative concentrations) as well as extremely high concentrations of tetracycline and ibuprofen. Using 16S and 18S rRNA gene primer sets, and qPCR the abundance of each population was monitored as well as the relative abundance of two populations under the various conditions. It was found that current environmental concentrations of ibuprofen stimulated protozoan growth but higher concentrations reduced their numbers especially in the presence of tetracycline. Finally using DGGE, the identity for some of the more abundant protozoa were identified and it was noted that high ibuprofen and tetracycline concentrations favored the abundance of some genera.

Christopher J.O. Baker, Roberta R. Fulthorpe, Kimberley Gilbride

• 2023

<p>The DNA fingerprinting techniques, 16S-restriction fragment length polymorphism (16S-RFLP), ribosomal intergenic spacer analysis (RISA) and repetitive extragenic palindrome PCR (Rep-PCR), were used for analyzing the bacterial communities of seven pulp and paper wastewater treatment systems. All three methods generate DNA fingerprints that can be compared using the computerassisted program, Gelcompar©. Community similarity coefficients were based on quantitative determinations of both the positions of the DNAbands and the band intensities in order to compare the relative differences in the populations. Unique 16S-RFLP DNA fingerprints were observed for each mill suggesting that individual mills contained phylogenetically different communities. However this method was not sensitive enough to detect differences within a mill treatment system from different locations or from different sampling times. The RISA method, which generated more complex fingerprints than 16S-RFLP, could, for some mills, discern differences between samples. The Rep-PCR technique, however, showed the highest degree of resolution and produced not only distinct patterns for each mill but also distinct fingerprints for the temporal and spatial samples from some of the treatment systems. The sensitivity of this method might potentially be used to monitor the stability of the bacterial community within a secondary treatment system.</p> <p><br></p>

Mauricio Barrera

• 2021

The reduction and degradation of total organic carbon (TOC) and bacteria inactivation efficiency using Vacuum-Ultraviolet (VUV) oxidation process Ultraviolet-C (UV-C) photolytic process, and their combination (UV-C/VUV and VUV/UV-C) from synthetic slaughterhouse wastewater was investigated. TOC removal rates achieved during continuous mode operation were 6.2%, 5.5%, 5.8%, and 6.1%, respectively. In a second stage, H₂O₂ was added to both processes, UV-C/H₂O₂ and VUV/H₂O₂, and it was found that TOC removal rates were increased twice as much during continious flow operation to 10.8% and 12.2%, respectively. The optimum molar ration of H₂O₂/TOC was found to be 2.5 and 1.5 for each process respectively. Finally, it was observed that all photochemical processes achieved over 99.999% (five logs) of bacteria inactivation in a short period of irradiation time, 27.6 sec.

Amir H. Tehrani, Kimberley Gilbride

• 2023

<p>The conventional biological treatment process can provide a favorable environment for the maintenance and dissemination of antibiotic- resistant bacteria and the antibiotic resistance genes (ARG) they carry. This study investigated the occurrence of antibiotic resistance in three wastewater treatment plants (WWTP) to determine the role they play in the dissemination of ARGs. Bacterial isolates resistant to tetracycline were collected, and tested against eight antibiotics to determine their resistance profiles and the prevalence of multiple antibiotic resistance. It was found that bacteria resistant to tetracycline were more likely to display resistance to multiple antibiotics compared to those isolates that were not tetracycline resistant. Polymerase chain reaction (PCR) was used to identify the tetracycline resistance determinants present within the bacterial communities of the WWTPs and receiving waters, and it was found that ARGs may not be released from the treatment process. Identification of isolates showed that there was a large diversity of species in both the tetracycline- resistant and tetracycline- sensitive populations and that the two groups were significantly different in composition. Antibiotic resistance profiles of each population showed that a large diversity of resistance patterns existed within genera suggesting that transmission of ARG may progress by both horizontal gene and vertical proliferation.</p> <p><br></p>

Κωνσταντίνος Παπαδόπουλος

• 2022

Η ανάπτυξη τεχνολογιών που επιτρέπουν την ανάκτηση ενέργειας και φυσικών πόρων είναι το κλειδί για την επίτευξη της βιωσιμότητας και της αποδοτικότητας στον τομέα της επεξεργασίας αποβλήτων. Η ενσωμάτωσή φωτοσυνθετικών μικροοργανισμών σε αερόβιες μικροβιακές κοινότητες μπορεί να αποτελέσει ένα βήμα προς αυτή την κατεύθυνση: η φωτοσύνθεση αντικαθιστά τον μηχανικό αερισμό του συστήματος, και οι φωτοσυνθετικοί μικροοργανισμοί καταναλώνουν τον παραγόμενο ανόργανο άνθρακα, μετατρέποντάς τον σε αξιοποιήσιμη βιομάζα. Η παρούσα εργασία επιχειρεί να αναπτύξει μια διεργασία που χρησιμοποιεί κοινότητες μικροφυκών-βακτηρίων για την επεξεργασία υγρών αποβλήτων, και μπορεί να αποτελέσει μία βιώσιμη εναλλακτική συμβατικών τεχνολογιών επεξεργασίας αποβλήτων.Χρησιμοποιώντας απόβλητα ζυθοποιίας ως σύστημα υπό μελέτη, αξιολογούνται δύο μικροβιακές κονότητες: (α) μία κοινότητα που απομονώθηκε από ενεργό ιλύ και (β) μία κοινότητα κυριαρχούμενη από το κυανοβακτήριο Arthrospira platensis. Παρόλο που και οι δύο κοινότητες επιβίωσαν στο απόβλητο, υψηλότεροι ρυθμοί ανάπτυξης, αφαίρεσης ρύπων, και ηπιότερες διακυμάνσεις στην σύσταση των μικροβιακών πληθυσμών παρατηρήθηκαν στην περίπτωση (α). Η ποικιλομορφία της μικροβιακής κοινότητας, τα μεταβολικά χαρακτηριστικά του κυανοβακτηρίου Leptolyngbya sp. που κυριάρχησε στις καλλιέργειες, και η συμβίωση με ετερότροφα βακτήρια επέτρεψε την αφαίρεση ανόργανων και οργανικών ρύπων, και τον σχηματισμό μεγάλων συσσωματωμάτων που μπορούν να διαχωριστούν με καθίζηση.Στη συνέχεια, αναπτύσσεται μια ημι-συνεχής διεργασία που αξιοποιεί τα χαρακτηριστικά των συσσωματωμάτων μικροφυκών-βακτηρίων. Οι στοιχειώδεις λειτουργικές αρχές της διεργασίας ενεργού ιλύος (καθίζηση και ανακυκλοφορία βιομάζας) διατηρούνται, ενώ ο αερισμός του συστήματος πραγματοποιείται αποκλειστικά μέσω της φωτοσύνθεσης. Τα αποτελέσματα υποδεικνύουν ότι η απόδοση της διεργασίας είναι σταθερή σε διαδοχικούς καλλιεργητικούς κύκλους, ενώ η ανακυκλοφορία της βιομάζας ευνοεί τον σχηματισμό μεγάλων συσσωματωμάτων που επιτρέπουν αποδοτικότερο διαχωρισμό βιομάζας και αφαίρεση ρύπων. Επιπλέον, η παραγωγή βιοαιθανόλης αξιολογείται ως στρατηγική αξιοποίησης της βιομάζας. Η παραγωγή βιοαιθανόλης, σε συνδυασμό με αποδοτική επεξεργασία αποβλήτων ζυθοποιίας αποδείχθηκε εφικτή, αλλά λιγότερο αποδοτική σε σχέση με συστήματα αποκλειστικά σχεδιασμένα για παραγωγή βιοκαυσίμων και συμβατικές τεχνολογίες παραγωγής βιοενέργειας, όπως η αναερόβια χώνευση.Τα πειραματικά αποτελέσματα προσεγγίστηκαν και αναλύθηκαν χρησιμοποιώντας μαθηματικά μοντέλα που αναπτύχθηκαν με το πακέτο ASM της IWA ως βάση και έμπνευση. Αποκαλύπτεται ότι η ένταση του φωτός και η σκίαση αποτελούν τους κύριους ρυθμιστικούς παράγοντες του συστήματος. Επιπλέον, υπογραμμίζεται περαιτέρω ο ρόλος της συσσωμάτωσης: δεν αποτελεί μόνο ένα μέσο διαχωρισμού της βιομάζας, αλλά επιτρέπει αποδοτικότερη διείσδυση της φωτεινής ακτινοβολίας σε πυκνές καλλιέργειας και προστατεύει τους μικροβιακούς πληθυσμούς από τη θήρευση. Το μοντέλο χρησιμοποιήθηκε επίσης για την εκτίμηση του λειτουργικού κόστους της διεργασίας σε μεγάλη κλίμακα. Αποδεικνύεται ότι ο συνδυασμός επεξεργασίας αποβλήτων με συσσωματώματα μικροφυκών-βακτηρίων και αξιοποίησης της βιομάζας με αναερόβια χώνευση μπορεί να εξαλείψει το λειτουργικό κόστος, αν και οι αυξημένες εδαφικές απαιτήσεις σε σχέση με άλλες συμβατικές τεχνολογίες πρέπει να ληφθούν υπόψιν.

Deniz Demirbilek, Ubeyde İpek, Ülkü Yetiş

Research Square • 2022

Abstract Activated sludge processes contains various groups of microorganisms with different metabolic properties, which are responsible for contaminants removal. Therefore, it is important to elucidate the general structure and functional properties of biomass in activated sludge processes. For this purpose, a full-scale domestic biological wastewater treatment plant in Tunceli (Turkey), Tunceli WWTP, was monitored to observe seasonal variations in process performance and biomass properties for a year. It was observed that nitrifying bacteria developed abundantly in the rainy and cool spring season as they were suppressed in summer because their large losses took placed due to an environment containing high alkalinity values. In September, aerobic heterotrophic, nitrify, denitrify, and anaerobic activities increased. It can be said that mature biomass contained young and active levels in an environment in which the sludge volume index (SVI) value increased to 196 mL/g. As a result of the improvement in the structural and functional properties of biomass, the nitrogen removal efficiency reached to 99%. Throughout whole study, the structural improvement observed in biomass reflected in its removal activity. The amount of biomass and removal activity decreased with the abundance of organic matter in the influent at the period in which biomass was closer to being categorized in the aged sludge class. The results showed that as the lowest mixed liquid volatile suspended solids (MLVSS) value of the year was 400 mg/L in November, MLVSS value reached the highest amount (1,400 mg/L) in December which aerobic heterotrophic activity accelerated with a decrease in organic matter level.

Ritesh Pattnaik, Lopamudra Ray, Koustav Saha et al.

Ammonia Oxidizing Bacteria • 2023

Although nitrogen fixation is essential for the continuation of life, excessive reactive nitrogen in surface and constructed water bodies as a consequence of limited tertiary wastewater treatment practices potentially harms the environment. At present, the majority of wastewater treatment units depend on various chemical approaches for the ready removal of reactive nitrogen species. However, because of both environmental and economic advantages, a significant shift towards the application of biological methods involving a specific group of microorganisms is under current emphasis. Excessive reactive nitrogen, besides having a negative impact on human health, also causes the pollution of water bodies triggering imbalances in aquatic ecosystems. Therefore, efficient strategies need to be adopted in order to remove excessive reactive nitrogen from different sources, including wastewater treatment plants. Globally, various technologies are in use to increase the efficacy of nitrogen removal treatment at an economic cost. The present chapter is aimed at outlining the different approaches for efficient nitrogen recovery and its multitude of sustainable applications.

Srishti Mishra, Brajesh K. Dubey, Makarand M. Ghangrekar

• 2025

The bioelectrochemical systems are sustainable solutions to face energy, water, and wastewater-related challenges. A three-chambered bioelectrochemical system, known as a microbial desalination cell (MDC), operates on the combined principles of a microbial fuel cell and electrodialysis. This self-powered system is capable of simultaneously treating wastewater and desalinating seawater. In the anodic compartment, microbial digestion of organic substrate treats wastewater. At the same time, the potential generation across the anode and cathode, resulting from electron production during the degradation process, leads to seawater desalination. Additionally, the oxygen reduction reaction (ORR) in the cathodic chamber significantly contributes to the overall performance of the system. Enhancing the ORR of the cell through catalyst incorporation has been shown to improve the system’s performance. The addition of a Sr-Mn-based perovskite, an abundant transition metal oxide compound, was synthesized using a facile method to be used as a cathode catalyst. The performance of the catalyzed reactor was compared to a non-catalyzed system with carbon electrodes. The addition of a catalyst resulted in a COD removal of 81.1 ± 0.5%, which was 35.5% higher than that recorded in the scenario without a catalyst. Similarly, in terms of desalination, the MDC with catalyzed cathode exhibited an 83.3 ± 1.2% desalination efficiency compared to the control MDC (45.76 ± 1.4%). This improved electrocatalytic performance of the system due to the catalyst was explained through the electrochemical analysis of the synthesized perovskite. The non-reliance of the MDC system on any external power source makes it a self-sustained and green technology for performing wastewater treatment and saltwater desalination, contributing to the Sustainable Development Goal 6 of clean water and sanitation.

Khaya Pearlman Shabangu, Babatunde Femi Bakare, Joseph Kapuku Bwapwa

Preprints.org • 2022

This study develops into the application of a combined MFC unit with chemical coagulation for total treatment of inert contaminants in complex substrates. Microbial Fuel Cell (MFC) technology converts chemical energy in the form of organic matter, into bioelectricity in an environmentally friendly and effi-cient manner, reducing carbon emissions and increasing bioenergy production. An evaluation of a la-boratory scale chemical coagulation using an aluminum and poly-based coagulant on how effective it can remove bulk impurities such as particulate COD and turbidity to obtain the purest and most cost-effectively treated wastewater using a jar test is being conducted in this current study. This study aims to find the most effective treatment technologies for wastewater recovery in breweries in order to achieve zero liquid effluent discharge (ZLED). The preliminary results showed that adding a modest amount of poly and a 50 % alum alone treatment improved COD, color, and turbidity reduction. The turbidity removal efficiency achieved after chemical coagulation treatment was 90.50 % and 59.36 % COD removal, demonstrating the benefits of adopting an alum/poly based technique. To determine ZLED, this study clearly advised a combined treatment technique, specifically the MFC-flocculator unit for efficient organics and inorganics removal.

Kiryl Hubchyk, Alena Hlushen, R. Birukou

5th International Scientific Conference on Microbial Biotechnology • 2022

Massive volumes of effluents discharged by the poultry-processing plants contain elevated levels of pollutants (dissolved keratins, blood, lipids and proteins), and are distinguished by high BOD and COD values, as well as by large concentrations of suspended particles [1]. Therefore, there is an urgent need to develop effective and eco-safe methods protecting the environment from contamination. Among such methods the application of efficient microbial degraders of toxicants, possessing enhanced flocculating and decomposing activity, that can be introduced into the decontamination units to supplement the microbiota of the activated sludge at various stages of treatment, seems to be especially promising. Currently, biopreparations of microbial consortia intended for remediation of the environments exposed to organic pollutants are widely spread. The most common constituents of such consortia represent such genera as Rhodococcus, Bacillus, Pseudomonas, Arthrobacter, etc. [2]. Our study was focused on the microorganisms of the Rhodococcus and Bacillus genera, which are able to utilize the organic compounds in the poultry processing wastewater. There were selected 14 variants out of 145 screened strains that were either deposited in the laboratory of environmental biotechnologies, Institute of Microbiology, NAS of Belarus, or isolated from effluents of poultry-processing plants. They were tested for the COD degradation activity in poultry-processing wastewater, assayed for the proteolytic and lipolytic activities [3], and estimated for the biosurfactant forming potential [4]. The degradation activity of the selected microbial cultures was investigated using poultry-processing effluents with initial COD value of 1144 O2/dm3. It was found that the top COD reduction was by B. subtilis 6/2-APF1, B. coagulans 1710, Bacillus sp. FL-9MV, Bacillus sp. FL X-5, Bacillus sp. PF1, R. ruber 30P, R. ruber 200N, R. ruber 1NG – 52,3-71,6%. The maximum proteolytic activity toward milk proteins was observed for B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5. The lipolytic activity on the tributyrin-containing medium was detected in all 14 tested strains – B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5, Bacillus sp. PF1, R. erythropolis 7D, R. erythropolis 23F, R. erythropolis 70F, R. ruber 2B, R. ruber 1NG, R. ruber 30P, Rhodococcus sp. P1, Rhodococcus sp. G13, R. ruber 200N with the last two being especially active. The highest capacity to produce biosurfactants in the specific nutrient medium with methylene blue was displayed by B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5. In addition, the ability to produce surface active agents was observed for the bacterial cultures of Bacillus sp. PF1, R. ruber 2B, Rhodococcus sp. R1-3FN, Rhodococcus sp. G13 and R. erythropolis 7D. Among the tested bacterial strains, the following cultures proved to be the most effective in decontamination of the poultry-processing wastewater: B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5, Bacillus sp. PF1. The above-listed microorganisms may act as promising components of the biopreparations promoting decontamination of the poultry-processing effluents.

Jerzy J. Ganczarczyk

Water Science and Technology • 1994

Basic forms of microbial aggregates generated in wastewater treatment and techniques used to study them, are described and discussed. The role of the free-setting velocity in evaluation of some physical properties of activated sludge flocs is emphasized. Several regression models were applied to correlate the flocs' settling velocity with flocs' size values. For the studied samples a simple linear model proved to be superior to a multiplicative one, and an introduction to this model of a settling shape factor function instead of constant intercepts, provided a very good correlation of the experimental data. It is expected that a difference between shape factors for the most stable conditions of the flocs and those for the flocs under the settling conditions will make it possible to determine softness or stiffness of these microbial aggregates.

Ιωάννης Σταυρακάκης

• 2025

Η παρούσα έρευνα εξετάζει καινοτόμες προσεγγίσεις για την ελαχιστοποίηση της περίσσειας ιλύος, με έμφαση στην εφαρμογή χημικών αποσυζευκτών και οζόνωσης σε συστήματα βιοαντιδραστήρων μεμβρανών (MBR). Οι χημικοί αποσυζευκτές, όπως η 3-χλωροφαινόλη (m-chlorophenol - mCP), η 4-νιτροφαινόλη (p-nitrophenol - pNP) κ.ά., έχει αποδειχθεί ότι μειώνουν αποτελεσματικά την περίσσεια ιλύος επηρεάζοντας την οξειδωτική φωσφορυλίωση, αποσυνδέοντας την παραγωγή ενέργειας από τη σύνθεση μικροβιακής βιομάζας. Αυτή η βιοχημική παρέμβαση όχι μόνο μειώνει την απόδοση της ενεργού ιλύος που παράγεται, αλλά επηρεάζει επίσης τα μικροβιακά μεταβολικά μονοπάτια, οδηγώντας στη προσαρμογή εξειδικευμένων μικροβιακών ομάδων και εντέλει σε αλλαγή της δομής της μικροβιακής κοινότητας. Η αλληλούχηση υψηλής απόδοσης γονιδίων 16S rRNA αποκάλυψε δυναμικές αλλαγές στον πληθυσμό βακτηρίων κατά την εφαρμογή των εξεταζόμενων χημικών αποσυζευκτών, επάγοντας σημαντικές επιπτώσεις στη μικροβιακή ποικιλότητα και στη μεταβολική δραστηριότητα της ιλύος. Η οζόνωση, μια συμπληρωματική χημική μέθοδος επεξεργασίας σε μονάδες επεξεργασίας υγρών αποβλήτων, περιλαμβάνει την εφαρμογή όζοντος στο μικτό υγρό, οδηγώντας στην οξειδωτική διάσπαση σύνθετων οργανικών ενώσεων. Η διαδικασία αυτή όχι μόνο ενισχύει τη βιοαποδομησιμότητα της ιλύος, οδηγώντας σε υψηλή μείωση της παραγόμενης ιλύος, αλλά συμβάλλει επίσης σε αλλαγή της δομής της μικροβιακής κοινότητας αναστέλλοντας επιλεκτικά ορισμένες ταξινομικές ομάδες βακτηρίων, ενώ προωθεί την ενίσχυση γενών ανθεκτικών στην οζόνωση. Μικροβιακές αναλύσεις έδειξαν ότι η προσθήκη οζονισμένης ιλύος μείωσε τις εξωκυτταρικές πολυμερείς ουσίες (Extracellular Polymeric Substances - EPS) και τα διαλυτά μικροβιακά προϊόντα (Soluble Microbial Products - SMP), που συμβάλλουν στο σχηματισμό βιοϋμενίου και στην έμφραξη της μεμβράνης. Ο συνδυασμός της οζόνωσης με την τεχνολογία MBR οδήγησε σε καλύτερη απόδοση επεξεργασίας διατηρώντας υψηλή ποιότητα εκροής, ενώ ελαχιστοποίησε την παραγόμενη περίσσεια βιοστερεών και τη μικροβιακή έμφραξη της μεμβράνης. Η υιοθέτηση αυτών των προσεγγίσεων βιοχημικής μηχανικής στην τεχνολογία MBR μπορεί να αντιμετωπίσει βασικές λειτουργικές προκλήσεις, όπως η έμφραξη των μεμβρανών των συστημάτων αυτών. Η παρακολούθηση των φυσικοχημικών παραμέτρων έπαιξε σημαντικό ρόλο στην αξιολόγηση της σταθερότητας και της απόδοσης του συστήματος MBR. Πραγματοποιήθηκε παρακολούθηση σε σταθερή βάση του διαλυμένου οξυγόνου (Dissolved Oxygen - DO), του χημικά απαιτούμενου οξυγόνου (Chemical Oxygen Demand - COD), του ολικού κατά Kjeldahl αζώτου (Total Kjeldahl Nitrogen - TKN) και του pH για τη βελτιστοποίηση των λειτουργικών παραμέτρων. Επιπλέον, η παρακολούθηση των συγκεντρώσεων EPS και SMP παρείχε χρήσιμες πληροφορίες για τυχόν έμφραξη της μεμβράνης και τη μεταβολική απόκριση του μικροβιακού πληθυσμού. Με τη βελτιστοποίηση της ηλικίας ιλύος (Sludge Retention Time - SRT) και τη εφαρμογή ελεγχόμενων επιπέδων διαλυμένου οξυγόνου, μεγιστοποιήθηκαν οι επιδόσεις του συστήματος MBR όσον αφορά την απομάκρυνση θρεπτικών ουσιών, την πρόληψη της βιολογικής έμφραξης της μεμβράνης και τη μείωση της παραγόμενης περίσσειας ιλύος. Η μείωση της διαμεμβρανικής πίεσης (Transmembrane Pressure - TMP) μετά την προσθήκη οζονισμένης ιλύος ανέδειξε τη θετική επίδραση της οξειδωτικής αυτής μεθόδου στην αντιμετώπιση της έμφραξης της μεμβράνης. Επιπλέον, η βελτιστοποίηση της ηλικίας ιλύος ενίσχυσε συνεργιστικά την αποτελεσματικότητα των εφαρμοζόμενων χημικών μεθόδων. Παρατηρήθηκε δραστική μείωση της συγκέντρωσης των βιοστερεών από 6500 mg/L και 5650 mg/L πριν από την προσθήκη pNP και mCP, σε 4070 mg/L και 3540 mg/L αμέσως μετά την προσθήκη αυτών των μεταβολικών αποσυζευκτών, η οποία συγκέντρωση βιοστερεών, ωστόσο, επανήλθε στις αρχικές τιμές μέσα σε διάστημα 10-12 ημερών, ενδεχομένως μέσω επιλεκτικής ανθεκτικότητας (ή/και μηχανισμούς αποδόμησης στην περίπτωση του pNP) ως τρόποι προσαρμογής στην παρουσία pNP και mCP. Η προσαρμογή αυτή υποδηλώνει ότι οι μικροβιακές κοινότητες της ιλύος προσαρμόστηκαν και εμφάνισαν ανθεκτικότητα κατά την έκθεση σε αυτούς τους μεταβολικούς αποσυζευκτές, παρατηρώντας ανάκαμψη στη σύνθεση της βιομάζας μετά από μια σύντομη περίοδο αναστολής. Η προσθήκη pNP δεν επηρέασε την απόδοση απομάκρυνσης COD (μέση απόδοση απομάκρυνσης COD ίση με 98% πριν και μετά την προσθήκη pNP), αν και η προσθήκη mCP οδήγησε σε σημαντική αύξηση της συγκέντρωσης COD τόσο στην εισροή όσο και στην εκροή του συστήματος, λόγω της πιο ανθεκτικής δομής αυτού του μορίου, το οποίο φαίνεται να ανθίσταται στη μικροβιακή διάσπαση σε σύγκριση με την pNP. Ωστόσο, κατά μέσο όρο 672 mg/L και 669 mg/L, καθώς και 847 mg/L και 642 mg/L COD πριν και μετά την προσθήκη αποζευκτή απομακρύνθηκαν στις περιπτώσεις της προσθήκης pNP και mCP αντίστοιχα, υποδεικνύοντας ότι η απομάκρυνση του COD του υπό επεξεργασία υγρού αποβλήτου (εξαιρουμένου του προστιθέμενου mCP) δεν επηρεάστηκε από την προσθήκη του αποζευκτή. Στην περίπτωση της pNP, η αποτελεσματικότητα απομάκρυνσης TKN και NH₄⁺-N μειώθηκε σημαντικά αμέσως μετά την προσθήκη του αποσυζευκτή, αν και με αντιστρεπτό τρόπο, καθώς οι νιτροποιητές αποκατέστησαν τη δραστηριότητα οξείδωσης της αμμωνίας μία εβδομάδα μετά την εφαρμογή της pNP. Όσον αφορά την προσθήκη mCP, σημειώθηκε εντονότερη αναστολή της νιτροποιητικής δραστηριότητας, αλλά επίσης με αντιστρεπτό τρόπο, μετά όμως από πιο παρατεταμένο χρονικό διάστημα. Όσον αφορά την προσθήκη pNP, παρατηρήθηκε μια αρχική μείωση των συγκεντρώσεων των πρωτεϊνικών SMP και EPS, η οποία σταδιακά σταθεροποιήθηκε, υποδεικνύοντας μικροβιακή διαταραχή που ακολουθήθηκε από προσαρμογή. Συγκριτικά, η προσθήκη mCP οδήγησε σε ακόμη πιο έντονη επίδραση στα εκλυόμενα SMP και EPS, ιδίως εκείνων πρωτεϊνικής φύσεως. Η προσθήκη pNP και mCP οδήγησε σε σημαντικές μεταβολές στη δομή των μικροβιακών κοινοτήτων, αν και αυτές διέφεραν σημαντικά ως προς την έκταση και τις μικροβιακές ομάδες που επηρεάστηκαν. Για την pNP, παρατηρήθηκαν μεταβολές κυρίως στη σχετική αφθονία των Bacteroidota (συν. Bacteroidetes), των Gammaproteobacteria και των Bacillota (συν. Firmicutes). Ειδικότερα, τα νιτροποιητικά βακτήρια διατήρησαν τη σχετική αφθονία τους, ακόμη και όταν η δραστηριότητά τους αναστάλθηκε προσωρινά. Η εκτίμηση της β-ποικιλότητας έδειξε σημαντική αλλαγή στη δομή της κοινότητας βακτηρίων μετά την προσθήκη pNP, γεγονός που αποδίδεται στην παροδική αναστολή που προκάλεσε η προσθήκη pNP. Γένη βακτηρίων που συμμετέχουν στην αποδόμηση της νιτροφαινόλης, όπως μέλη των γενών Clostridium, Cytophaga και Pseudomonas, ενισχύθηκαν μετά την προσθήκη pNP. Συγκριτικά, η προσθήκη mCP οδήγησε σε πιο έντονες αλλαγές στη μικροβιακή ποικιλότητα και δομή, όπως αποδεικνύεται από τη σημαντική μείωση των δεικτών βιοποικιλότητας. Επίσης, σημειώθηκε εντονότερη αναστολή των νιτροποιητών. Ειδικότερα, δεν ανιχνεύθηκαν μέλη των γενών Nitrosomonas και Nitrospira μετά την προσθήκη mCP, υποδεικνύοντας ότι η mCP προκάλεσε σοβαρή αναστολή στις ταξινομικές αυτές ομάδες βακτηρίων. Η προσθήκη mCP ευνόησε τα ανθεκτικά σε αυτήν γένη, όπως είναι μέλη των γενών Pseudomonas και Arcanobacterium, αναδεικνύοντας την επιλεκτική πίεση που ασκείται στις μικροβιακές κοινότητες της ενεργού ιλύος από την mCP, οδηγώντας στην επιβίωση και κυριαρχία των πιο ανθεκτικών στις χλωροφαινόλες, ταξινομικών ομάδων. Η οζόνωση οδήγησε στην οξειδωτική διάσπαση ανθεκτικών συστατικών της οργανικής ύλης, ενισχύοντας τη βιοαποδομησιμότητα της ιλύος και τη διάσπαση θρεπτικών συστατικών. Τα αποτελέσματα έδειξαν μείωση κατά 38% των εξωκυτταρικών πολυμερών ουσιών (EPS) και μείωση κατά 32% των διαλυτών μικροβιακών προϊόντων (SMP), βασικών παραγόντων που συμβάλλουν στο σχηματισμό βιοϋμενίου και στην έμφραξη της μεμβράνης. Ο συνδυασμός της οζόνωσης και της τεχνολογίας MBR βελτίωσε την απόδοση του συστήματος, επιτυγχάνοντας ποσοστά απομάκρυνσης COD και TKN άνω του 95%. Η οζόνωση της περίσσειας ιλύος και η επιστροφή της στον MBR τμηματικά επέτρεψε τη μείωση των βιοστερεών του μεικτού υγρού από μια μέγιστη τιμή 9,8 g/L πριν από την προσθήκη, σε μια μέση συγκέντρωση βιοστερεών 5,5 ± 0,2 g/L μετά την προσθήκη οζονισμένης ιλύος, διατηρώντας μια σταθερή συγκέντρωση βιοστερεών για παρατεταμένη χρονική περίοδο. Όσον αφορά την προσθήκη οζονισμένης ιλύος, τα κυρίαρχα φύλα στον MBR ήταν τα Pseudomonadota και Bacteroidota, ακολουθούμενα από τα Planctomycetota, Actinomycetota και Chloroflexota. Τα γένη Lewinella και Methylophilus ήταν κυρίαρχα πριν από την προσθήκη οζονισμένης ιλύος, ωστόσο, μετά την προσθήκη, εντός του φύλου Bacteroidota, παρατηρήθηκε σημαντική διαδοχή, με τα Aureliella, Flavobacterium και Chryseosolibacter να γίνονται κυρίαρχα, σε σχέση με τα Lewinella. Η ανάλυση β-ποικιλότητας αποκάλυψε μια σημαντική μετατόπιση στη δομή της κοινότητας βακτηρίων, η οποία σταθεροποιήθηκε εντός 10 ημερών μετά την τμηματική προσθήκη οζονισμένης ιλύος. Αξίζει να σημειωθεί ότι οι νιτροποιητικές κοινότητες παρέμειναν ανεπηρέαστες, γεγονός που υποδηλώνει ότι είναι ανθεκτικές σε μέτριες συγκεντρώσεις όζοντος. Τα ευρήματα αυτά υπογραμμίζουν τη δυνατότητα εφαρμογής χημικών αποσυζευκτών και τμηματικής προσθήκης οζονισμένης ιλύος για την προώθηση της τεχνολογίας MBR. Ο έλεγχος της βιοεπεξεργασίας σε συνδυασμό με τις γνώσεις που αποκτήθηκαν για τις μικροβιακές κοινότητες κατά την εφαρμογή των παραπάνω μεθόδων ελέγχου της περίσσειας ιλύος συνέβαλαν στην επίτευξη βελτιωμένης απόδοσης επεξεργασίας, μειωμένης παραγωγής βιοστερεών και βελτιωμένης σταθερότητας του συστήματος MBR, ανοίγοντας το δρόμο για πιο βιώσιμες και οικονομικά αποδοτικές λύσεις επεξεργασίας υγρών αποβλήτων.

GM Itheshamul Islam

• 2021

Nitrification is an essential microbial process in the global nitrogen cycle. The first step of nitrification is ammonia oxidation which is achieved by bacteria and archaea and is crucial in decreasing ammonia concentrations that are persistently high in wastewater. This study examined the composition, abundance and identity of the microbial community in activated sludge with a focus on characterizing ammonia oxidizing bacteria and archaea in a full-scale municipal wastewater treatment plant (MWTP). Specifically, two pharmaceutical compounds Tetracycline and Ibuprofen, and their effects on the community composition of bacteria and protozoa in activated sludge was investigated using PCR coupled with denaturing gradient gel electrophoresis (DGGE). In addition, the composition, abundance and activity of the ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) were analyzed from aerobic activated sludge, recycled sludge and anaerobic digesters of the Humber MWTP using molecular techniques such as PCR, Quantitative PCR, Reverse Transcription-PCR and DGGE. The findings demonstrated that Tetracycline did not appear to alter community composition of bacteria in the activated sludge, rather, the operational parameters of the sequencing batch reactors such as feeding rates and SRT have shown to alter the richness of bacterial communities. However, Ibuprofen affected some members in the protozoan community in activated sludge. In the full-scale Humber MWTP using the conventional activated sludge system, the aeration tanks contained 1.8 × 105 copies of the AOB amoA gene per 100 ng of DNA. In contrast, the anaerobic digester tanks contained 7.3 × 102 copies of the AOA amoA gene per 100ng of DNA. This study also found that AOB were dominant in activated sludge samples, regardless of the operational parameters. The quantification of cDNA transcripts of the amoA gene also indicated that AOB may be more active than AOA in the activated sludge system. Overall, it appears that AOA are very niche specific and thrive in very low oxygenated environments, while AOB proliferate and play a major role in aerobic ammonia oxidation occurring in MWTPs.

Romeo Gabriel Dumitrache

• 2021

A moving bed biofilm reactor was studied for its capability of carbon oxidation and nitrification. The hybrid system made use of suspended biomass in the forms of microbial aggregates and attached biomass in the form of biofilms on suspended carriers. The carriers used for biofilm support were made of polyethylene and have a wagon wheel shape. The carrier fill ratio, which is defined as the volume ratio of carrier to the whole reactor was a key characteristic parameter of the reactor. The experimental runs used different carrier filling ratios from 25 to 50% to determine the optimal operating value for this type of hybrid reactor. Also the nutrient conditions were modified to test the capacity of the system to adapt to various changes in phosphorus loading in the influent wastewater. The results showed that for an influent chemical oxygen demand (COD) of 600 mg/L, ammonia of about 24 mg/L and hydraulic reaction time of 6 hours there was no difference in the performance of the system under the different carrier filling rations.

Rubini S

JOURNAL OF ADVANCED APPLIED SCIENTIFIC RESEARCH • 2017

Environmental issues associated with water sanitation are not confined to developing countries alone but are the most basic human and environmental necessities all over the world. Wastewater sources are major causes for environmental pollution in surface and ground water bodies. Current wastewater treatment technologies are not sustainable to meet the ever growing water sanitation needs due to rapid industrialization and population growth, simply because they are energy and cost intensive leaving latitude for development of technologies that are energy conservative or energy yielding. For the present and future context, microbial fuel cells technology may present a sustainable and an environmentally friendly route to meet the water sanitation needs. Microbial fuel cell based wastewater systems employ bio-electrochemical catalytic activity of microbes to produce electricity from the oxidation of organic, and in some cases inorganic, substrates present in urban sewage, agricultural, dairy, food and industrial wastewaters. It provides an overview of current energy needs for wastewater treatment and potential energy recovery options followed by a comprehensive review of the principles of wastewater treatment, substrate utilization (organic removal), recent process developments, nutrient and metal removal capacities in microbial fuel cells. Several issues related to process performance, organic removal capacities and potential environmental impacts were discussed in detail

Geeta Kumari, Aman Jaiswal, Devashish Pathak et al.

Agriculture Association of Textile Chemical and Critical Reviews • 2025

Naturally occurring bacteria in wastewater have a significant potential for bioremediation, making them valuable for biological wastewater treatment. The effectiveness of microbial communities in breaking down pollutants depends on their diversity and metabolic capabilities. Therefore, developing environmentally friendly, indigenous microbial consortia is crucial for efficient wastewater treatment. In this study, 20 bacterial strains were isolated from wastewater samples collected from the dairy industry, sugar industry, and hostel sewage water in Pusa, Bihar. These isolates were screened for their ability to degrade starch, protein, and fat, as well as their potential to reduce Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Among the 20 isolates, 18 exhibited starch degradation, 10 showed protein degradation, and 11 demonstrated fat degradation. Notably, seven isolates (DS-13, DS-27, DS-57, DS-58, DS-67, DS-68, and DS-72) exhibited all three degradation activities and were further analyzed for their impact on BOD and COD reduction. Out of these seven isolates, three (DS-58, DS-67, and DS-72) demonstrated the highest reductions in BOD and COD when inoculated into autoclaved effluents from the dairy industry, sugar industry, and hostel sewage. In contrast, the blank (un-autoclaved effluents without bacterial inoculation) recorded BOD levels of 835 mg/L, 1035 mg/L, and 620 mg/L, and COD levels of 1680 mg/L, 2280 mg/L, and 1470 mg/L for the respective effluent sources. To enhance biodegradation efficiency, these three bacterial isolates were combined into different formulations, creating four distinct microbial consortia. Among them, consortium C4 (comprising DS- 58, DS-67, and DS-72) exhibited the highest biodegradation efficiency, with starch degradation of 14 mm, protein degradation of 24 mm, and fat degradation of 18 mm. Additionally, C4 significantly reduced BOD levels from 115 mg/L to 353 mg/L and COD levels from 407 mg/L to 641 mg/L. These findings indicated that the formulated C4 consortium has strong potential for biological wastewater treatment by effectively breaking down organic pollutants and reducing water pollution. Its application in wastewater management can contribute to environmentally sustainable bioremediation strategies.

Suraj Sevda, Ibrahim M Abu Reesh, Zhen He

Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1 • 2016

The availability of drinking water from the current available sources is decreasing due to the high demand and population increase. Seawater is a potential source for drinking water but the current desalination technology is energy intensive, therefore energy efficient desalination technology is desired. In the past decade microbial fuel cells (MFC) were emerged for simultaneous wastewater treatment and bioelectricity generation, in the anodic chamber of MFCs, microbes work as a biocatalyst to generate electrons from the oxidation of the organic compounds (wastewater) and transfer them to the anode electrode. These electrons flow through an external circuit to the cathode electrode where they used to reduce terminal electron acceptors (e.g., oxygen). Microbial desalination cells (MDC) are new potential technique for seawater desalination, in this device energy from wastewater is extracted by using microbes and without any external energy source, water desalination is driven. To convert an MFC to an MDC, a middle chamber is inserted in between the anodic and cathodic chambers of MFC using a pair of anion and cation exchange membranes. This middle chamber works as a desalination chamber in the MDC (Fig. 1). The cations and anions from the desalination chamber moved to the anodic and the cathodic chambers, respectively, due to the cell potential difference between the anode electrode and the cathode electrode; as a result, salts are removed from the saltwater. The first MDC study was reported in 2009 and since then there have been nearly 74 papers published about various aspects of MDC design and development, indicating a strong interest and rapid development of this technology. During this short period of time, various MDC designs were developed for salt removal and wastewater treatment. The desalination chamber volumes were increased from 3 ml to 105 liters and further progress is going on for salt removal and at the same time wastewater treatment. The performance of MDC was investigated using various concentrations of saline water in desalination chamber using industrial or synthetic wastewater in the anodic chamber. Different MDC designs were reviewed here. These developed new MDC designs named as air cathode MDC, stacked MDC (SMDC), up flow MDC (UMDC), recirculated MDC (RMDC), microbial electrodialysis cell (MEDC), submerged microbial desalination- denitrification cell (SMDDC), microbial capacitive desalination cell (MCDC) and osmotic microbial desalination cell (OsMDC). Different anion and cation exchange membranes were compared for power generation and desalination efficiency. This paper also reviews different substrates that have been used in MDCs so far. The MDCs provide an energy self-sustainable system in that water desalination and wastewater treatment conducted by using microbes as catalyst in the anodic chamber. Still the available MDCs were very small in volume that can't meet today's water desalination needs. In the long term operation of MDC, the membrane fouling and electrode stability are still two major problems limiting the development of MDCs. The possibility of scale-up, possible future potentials for synchrony of the MDCs with current desalination techniques were also discussed. Case study with real wastewater in the anodic chamber and real seawater in the desalination chamber were also discussed. Acknowledgements This work was made possible by NPRP grant # 6-289-2-125 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. Reference Sevda, S., Yuan, H., He, Z., Abu-Reesh, I.M., 2015. Microbial desalination cells as a versatile technology: Functions, optimization and prospective. Desalination 371, 9–17. doi:10.1016/j.desal.2015.05.021

Rachna Jain, Saravana Devi, Dipanjali Majumdar

Research Square • 2022

Abstract Wastewater management is a powerful tool for restricting containment and recycling of wastewater upto surface/drinking standard as per end use. The present study is designed to explore the treatment potential of indigenous microflora for effective and efficient recycling of sanitary landfill leachate under in-situ conditions. Three indigenous strains were screened and characterized as MT186162, MT186163, and MT186164. Their i n-situ metabolic potential was observed by augmentation into leachate under optimized culture conditions and depicted in the form of percent reduction in major pollutant parameters viz. BOD, COD, Chlorides, phenols, TDS, and TKN at regular time intervals. In our knowledge, it is the very first study on in-situ leachate treatment by indigenous microflora. Results revealed that bacterial growth correlated well with their metabolic potential ( p>0.01 ). >83% of BOD, COD, phenolics, and TKN were reduced with water quality reaching surface discharge standards after 41 days of augmentation. Microbial metabolic potential varied significantly ( p>0.05 ) in the order of MT186163> MT186162> MT186164 and followed first order kinetics with rate constants k deg - 0.0062-1.131 day -1 and t 1/2 of 0.612-111.7 days. In concurrence, the Leachate Pollution Index of the landfill site also dropped significantly from 13.39 to 5.1-5.2. AMES test exhibits no mutagenicity in the treated leachate samples. The study concludes that isolated strains are pervasive towards leachate contamination and efficiently reduced it upto surface wastewater discharge standards. Hence their potential can be utilized further while designing commercial leachate treatment strategies for wastewater recycling.

Mercedes Villar Navarro, Miguel Angel Cabezón, Patricia C. Damiani

Journal of Chemistry • 2018

In the present work, a chemometric-assisted spectrofluorimetric method has been developed for the simultaneous determination of natural fluorescent pesticides, carbaryl, carbendazim, and thiabendazole, in orange and banana. Only a simple extraction with methanol was required as sample pretreatment. Emission-excitation fluorescence matrices were obtained and resolved by using a second-order multivariate calibration method based on unfolded partial least-squares combined with residual bilinearization (U-PLS/RBL) for achieving “second-order advantage.” In this way, pesticides were determined in fruits even in the presence of inner filter effects, background interactions, strong spectral overlapping, and unexpected components. U-PLS can cope with effects that cause trilinearity loss such as, inner filter effects, including background in the calibration set; meanwhile, RBL allows to resolve the presence of unexpected components. The extraction technique was validated against a commonly applied technique based on the use of ethyl acetate and sodium sulfate. Besides, results obtained for real samples were statistically compared with those obtained by using HPLC. LODs of 0.038, 0.054, and 0.018 mg·kg −1 and 0.044, 0.072, and 0.020 mg·kg −1 were obtained for carbaryl, carbendazim, and thiabendazole in banana and orange samples, respectively; values were in accordance with the MRLs (Maximum Residue Limits) established by different official control organizations such as National Food Safety and Quality Service (SENASA), Codex Alimentarius (based on Food and Agriculture Organization (FAO) of the United Nations and World Health Organization (WHO), and Environmental Protection Agency (EPA).

Hyeonaug Hong, Jang Mee Lee, JaeHyoung Yun et al.

ECS Meeting Abstracts • 2020

Thylakoids are the photosynthetic complexes that absorb light energy to produce photosynthetic electrons (PEs) in the chloroplast of plant cells. PE production starts from water splitting at photosystem II (PSII) in the thylakoid membrane and they are excited by absorbing photon energy. Over the last decade, many researchers have attempted to extract PEs from thylakoid by enhancing attachment of thylakoid membranes to an electrode or using artificial mediators. However, these have some limitations including increased ohmic resistance from the length of tethering molecules and energy loss due to artificial mediators. In this study, we propose a photosynthetic electrochemical cell based on RuO 2 nanosheet modified electrode for the photosynthetic energy harvesting from thylakoids. RuO 2 is known as one of the most conductive metal oxides. Metal oxides have partially positive charges that can improve attachment of negatively charged thylakoids to the electrode. Also, partially positively and negatively charged characteristics of RuO 2 surfaces induce ensemble docking between electron carriers and electrode surface, which can attract both negatively charged electron carriers and positively charged electron carriers. Furthermore, RuO 2 nanosheets show a unique characteristic of proton adsorption, which can sustain positive electrical potential during PEs extraction. For photosynthetic energy harvesting, the photosynthetic electrochemical cell was constructed with anode based on thylakoid and air-cathode based on Pt-C, which separated by a proton exchange membrane. The light was controlled by a 100 W halogen lamp to operate the photosystem so that excited PEs can be extracted to the electrode. The surface potential of RuO 2 nanosheets modified electrodes was 250 mV vs. Ag/AgCl, which shifted positively more than 100 mV than that of the bare Au electrode. From the inspection of RuO 2 lattice by x-ray absorption spectroscopy, positively shifted surface potential is the result of proton adsorption. A positively biased electrode surface can induce a large amount of PEs extraction from the electron carriers than the Au electrode. When the light is illuminated on the thylakoids deposited electrodes, 8.9 ± 6.3 mV and 88.7 ± 13.8 mV of the surface potentials were measured from the Au and the RuO 2 modified electrode, respectively. These lowered electrode potentials are due to the redox potential of the electron carriers on the electron transport chain of the thylakoid membrane. The open-circuit voltages (OCV, the subtracted potential between the cathode and the anode) were measured 575.1 ± 6.4 mV and 424.0 ± 17.2 mV from the Au and the RuO 2 electrode, respectively. Although OCV of the RuO 2 electrode is lower than the Au electrode, the power density of the RuO 2 electrode shows 4 times higher than the Au electrode, and this is due to the enhanced PEs extraction by both the surface charge and the proton adsorption characteristics of RuO 2 nanosheets.

H. Madi, S. Diethelm, S. Poitel et al.

Fuel Cells • 2015

Abstract This work presents the poisoning effect of organic oxo‐silicon compounds (siloxanes) which are generally found in sewage biogas. Lifetime and durability associated with solid oxide fuel cell (SOFC) technology is strongly related to the amount of contaminants that reach the stack. Several experiments on Ni anode‐supported (AS) single cells are performed in order to clarify the mechanism of degradation and also the possibility of cell performance recovery. Three experiments focus on the degradation and recovery of AS Ni‐YSZ fed with H 2 , co‐feeding 5 ppm D4‐siloxane (octamethylcyclotetrasiloxane, C 8 H 24 O 4 Si 4 ) as representative compound for the organic silicon species, at 800 °C. A fourth experiment focuses on the durability of the AS Ni‐YSZ cell with variable concentrations of the impurity (0–5 ppm), during steady state polarization (0.25 A cm −2 ) for 250 h, using simulated biogas‐reformate fuel H 2 /CO/CO 2 /H 2 O: irreversible degradation was observed with the D4‐impurity feed in the anode gas. Post‐test scanning electron microscopy (SEM) results indicate formation of SiO 2 (s) deposits, which block pores and reduce the TPB length.

Kottisa Patnaik, Yueying Peng, Rajashekar Badam et al.

ECS Meeting Abstracts • 2021

Currently graphite is the most commercially used anode material for lithium-ion batteries (LIB), however its limited theoretical capacity of 372 mAhg -1 and slow kinetics cannot satisfy the requirements for EVs. Hence, alternative high energy density anode materials with fast kinetics are the need of the hour. The most recent development involves Mitsubishi Outlander PHEV which takes around 40 minutes for empty to full charging. Extreme fast charging, with a goal of 15 minutes fast charging, is poised to accelerate mass market production of electric vehicles. Extensive research is now directed towards carbonaceous materials that can fulfill the requirements for EV application. Key strategies involved in improving the rate capability of carbonaceous materials are (a) heteroatom doping, especially nitrogen doping and (b) increasing the d-spacing for accessing more active sites. Using conventional methods of heteroatom doping like pyrolysis of graphene oxide with urea or melamine as nitrogen source led to inclusion of up to 12 at% of nitrogen in general. Inclusion of nitrogen showed improvement in rate capability and capacity. Further search to increase nitrogen content led to the application of graphitic carbon nitride with nearly 55 at% nitrogen. Nevertheless, due to less electronic conductivity and change of crystallinity upon lithiation curbed its application in lithium-ion battery. So, currently our objective is to use nitrogen rich polymer as a single source of nitrogen and carbon to prepare heavily nitrogen doped carbon with nearly 20 at% of nitrogen with increased d-spacing and understand its effect on Li ion storage. Poly (2, 5-benzimidazole) (PBI) was synthesized by homo-polycondensation method using a bio derivable starting material 3, 4-diaminobenzoic, as earlier reported by Kaneko et.al 1 . The as prepared PBI was ground into fine powder before pyrolyzing at 800 ℃ in nitrogen atmosphere. Obtained carbon material was washed with HCl and water repeatedly and dried at 80 ℃ under vacuum before grinding into fine powder using mortar and pestle. Obtained material was systematically characterized before preparation of anodes for Li ion battery application. The SEM-EDX data revealed the content of nitrogen was as high as 18 at%. Using XPS studies, different types of nitrogen moieties were identified. Deconvolution of N1s peak revealed the presence of nitrogen in four different forms, graphitic nitrogen (10.3%), pyridinic nitrogen (6%), pyrrolic nitrogen (0.6%) and oxidized nitrogen (0.6%). The presence of pyridinic and graphitic nitrogen improve the electrical conductivity. The presence of high pyridinic nitrogen results in improved electrochemical activity. The contribution of pyridinic nitrogen in lithium storage is known to be maximum. XRD technique was utilized to understand the d-spacing of the material. Reflection corresponding to C (002) was used to calculate d-spacing. The results revealed that the d-spacing was found to be 3.5 Å which is nearly 0.2 Å higher than conventional graphite. The increased d-spacing can promote in faster diffusion of Li ion during intercalation and de-intercalation. TEM micrographs revealed the presence of macropores and mesopores. Using Cyclic Voltammograms at different scan rates and Randles Sevcik equation, the diffusion coefficient was calculated. Diffusion coefficient of PY PBI 800 was found to be several times higher than the conventional graphite anode, attributed to the increased d-spacing along with porous nature. Upon galvanostatic charge-discharge studies at different current rates, anode showed reversible capacity with nearly 99% coulombic efficiency upto 5C (1.8 Ag -1 ) rate. Further, long cycling studies were performed for >1000 cycles at 0.4, 0.8 and 1.8Ag -1 rates. Results indicated that PY PBI 800 can deliver highest de-lithiation capacity of ̴ 260 mAhg -1 at specific capacity of 0.4 Ag -1 rate (Fig) with nearly 88% capacity retention after 1000 cycles. At higher current rate of 0.8Ag -1 , and 1.8 Ag -1 it showed highest discharge capacity of 165 mAhg -1 and 135 mAhg -1 with 90% and 75% capacity retention after 1000 cycles respectively. At 5C current rate, the battery can be charged and discharged in just 9 mins. Further, full cell was studied with LiCoO 2 as cathode and PY PBI 800 as anode. Full cell studies also revealed the promising nature of PY PBI 800. Thus, carbonization is found to be a single method to enable high N-doping and increased d-spacing. The battery’s performance of charge discharge in just 9 min at 5C, with good capacity retention of nearly 75% after 1000 cycles demonstrated its promising potential for EV application. References: (1) Nag, A., Ali, M.A., Singh, A., Vedarajan, R., Matsumi, N., Kaneko, T., J. Mater. Chem. A, 2019,7, pp: 4459-4468 Acknowledgement We thank the financial support from Strategic Innovation Promotion Program (SIP), Technologies for Smart Bio-Industry and Agriculture, Japan. Figure 1

Zainab Karam, Chiara Busa

ECS Meeting Abstracts • 2023

Lithium Ion batteries (LIB) demand has shown an exciting increase lately, particularly looking for light-weight solution for portable devices [1], [2]. Recently, The development and implementation of electrode material production techniques pushed the LIB's current state performance to further improvement. Silicon (Si) anode-based electrodes are considered an attractvie alternative to conventional graphite electrodes due to their high specific capacity [3]. Theoretically, Si could alloy with Li up to Li 4.4 Si and result in a specific capacity of 4200 mAh/g, where the mechanical stress within the electrode material causes loss in the conductivity and breaking of the cell. To overcome this issue, different methodologies have been tested for further improvement of Si implementation with different nanostructures [4]. On the other hand, the production rate of LIB is very important to meet the high demand for different technologies. and, a commercial Si grade is highly recommended along with the conventional tape-casting production method. Furthermore, water-based binders, such as Polyacrylic Acid and Carboxy methyl Cellulose (cellulose-based binders) plays an important role in electrode preparation, where it is supporting the volume expansion of Si and preserveing electrode morphology [5]. Herein, we focus on producing a high-quality Si electrode with cellulose binder, enhanced by conductive carbon allotrope additives. In this study, different Si grades will be tested with different concentrations along with conductive and binder [6]. Electrochemical characterization of the Si anode half cell , such as cycling, cyclic voltammetry, and Impedance spectroscopy vs Li + metal shows extended and stabilized cycling performance, inferring a reduced anode pulverization. References [1] M. Wakihara, ‘Recent developments in lithium ion batteries’, Mater. Sci. Eng. R Rep. , vol. 33, no. 4, pp. 109–134, Jun. 2001, doi: 10.1016/S0927-796X(01)00030-4. [2] B. Scrosati, ‘Recent advances in lithium ion battery materials’, Electrochimica Acta , vol. 45, no. 15, pp. 2461–2466, May 2000, doi: 10.1016/S0013-4686(00)00333-9. [3] S. Chae, M. Ko, K. Kim, K. Ahn, and J. Cho, ‘Confronting Issues of the Practical Implementation of Si Anode in High-Energy Lithium-Ion Batteries’, Joule , vol. 1, no. 1, pp. 47–60, Sep. 2017, doi: 10.1016/j.joule.2017.07.006. [4] J. Cho, ‘Porous Si anode materials for lithium rechargeable batteries’, J. Mater. Chem. , vol. 20, no. 20, pp. 4009–4014, May 2010, doi: 10.1039/B923002E. [5] P. Parikh et al. , ‘Role of Polyacrylic Acid (PAA) Binder on the Solid Electrolyte Interphase in Silicon Anodes’, Chem. Mater. , vol. 31, no. 7, pp. 2535–2544, Apr. 2019, doi: 10.1021/acs.chemmater.8b05020. [6] A. Meyer, F. Ball, and W. Pfleging, ‘The Effect of Silicon Grade and Electrode Architecture on the Performance of Advanced Anodes for Next Generation Lithium-Ion Cells’, Nanomaterials , vol. 11, no. 12, Art. no. 12, Dec. 2021, doi: 10.3390/nano11123448.

Y. Bai, C. Wang, C. Jin et al.

Fuel Cells • 2011

Abstract Anode current collection points (ACCPs) were fabricated on the outside surface of a tubular anode‐supported solid oxide fuel cell (SOFC). The ACCPs were distributed axially along the SOFC tube with the distance between every adjacent two ACCPs the same. The effect of collecting current with different number of ACCPs on the performance of the SOFC was studied. It was found that with the same effective area, using more ACCPs to collect the current leads to better performance, while with a SOFC with a determined total surface area, there is an optimum number of ACCPs to be made and used considering the area occupied by the ACCPs themselves.

Pei Fu, Yuansheng Song, Jian Yang et al.

Journal of Heat Transfer • 2020

Abstract Gradient particle size anode has shown great potential in improving the electrical performance of anode-supported solid oxide fuel cells (SOFCs). In this study, a 3D comprehensive model is established to study the effect of various gradient particle size distribution on the cell electrical performance for the anode microstructure optimization. The effect of homogeneous particle size on the cell performance is studied first. The maximum current density of homogeneous anode SOFC is obtained for the comparison with the electrical performance of gradient anode SOFC. Then the effect of various gradient particle size distribution on the cell molar fraction, polarization losses, and electronic current density distribution is analyzed and discussed in detail. Results show that increasing the particle diameter gradient can effectively reduce the anodic concentration overpotential. Decreasing the particle diameter of anode functional layer 2 is beneficial for reducing the activation and ohmic overpotentials. On these bases, the comprehensive electrical performance of SOFCs with gradient particle size anode and homogeneous anode is compared to highlight the optimal gradient particle diameter distribution. In the studied cases of this work, the gradient particle diameter of 0.7 μm, 0.4 μm, and 0.1 μm at anode support layer (ASL), anode functional layer 1, and anode functional layer 2 (case 3) is the optimal particle size distribution.

Nak Gyu Go, Seung Taek Lee, Woo Young Yoon

ECS Meeting Abstracts • 2019

Over the last several decades, new battery technologies have been developed due to the need for consistently high energy density batteries. Lithium metal is the ideal cathode for next-generation lithium batteries, because it has a high specific capacity (3860 mAh g −1 ) and the lowest reduction potential (−3.040 V vs. standard hydrogen electrode, SHE). However, safety issues caused by Li dendritic growth during Li plating interfere with the use of lithium metal-based rechargeable batteries. Li dendrites can cause dead lithium to accumulate on the lithium metal surface, resulting in increased resistance at the interface or short-circuiting, which can lead to explosion. Several studies have been proposed to inhibit the growth of lithium dendrites, such as electrolyte additives, surface coating, separator modification, and lithium metal host. In this experiment, Li was isolated by physically mixing Li and graphite to form a composite electrode, thereby suppressing Li dendrite growth. Li metal powder is synthesized by the droplet emulsion technique and this shape is prohibited dendrite growth. These Li metal powder+graphite composite anode was experimented with constant current charge/discharge tests and constant voltage tests. And the structure, morphology, and electrochemical properties of the new type of battery’s electrode were investigated by the implementation of X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and energy dispersive spectroscopy (EDS). The result was analyzed by electrochemical impedance spectroscopy (EIS).

Farshid Zabihian, Asad Davari, Gifty Osei-Prempeh

International Journal of Renewable Energy Resources • 2023

The objective of this paper is to present the results of experimentations on the state-of-the-art anode electrocatalysts and the membrane-electrode assemblies (MEAs) developed for direct carbon monoxide fuel cells (DCMFCs). The custom-made platinum-ruthenium (Pt-Ru) MEAs along with a commercial MEA were tested to evaluate the impacts of cell temperature, different types of fuel and oxidant, the flow rate of fuel and oxidant, and humidification temperature on the performance of the MEAs. It was shown that both the catalyst manufacturing process and the test procedure are repeatable. Also, it was shown that the performance of Pt-Ru cells when fueled by CO and CO-containing fuels was markedly inferior to that of hydrogen-fueled fuel cells. However, there were some promising signs that with the right catalysts and optimum operating conditions, the performance of DCMFCs can be significantly improved. It was also shown that increasing the operating temperature always improved the performance. While increasing the flow rates of the reactants improved the performance of the MEAs, there was a limit to this improvement. Furthermore, generally speaking, the performance of the MEAs was better when fed with CO rather than CO-N2 and O2 rather than air but the actual impact depended on other operating conditions.

Martin Andersson, Xinrong Lu, Jinliang Yuan et al.

ECS Transactions • 2011

In this study a two dimensional CFD (COMSOL Multiphysics) is employed to study the effect of anode microscopic structures on the transport phenomena and reactions for an anode-supported solid oxide fuel cell (SOFC). FCs can be considered as energy devices, involving multiple processes, such as (electro-) chemical reactions, heat exchange, gas- and ionic transport. All these complex processes are strongly integrated, needing modeling as an important tool to understand the couplings between mass-, heat-, momentum transport and chemical reactions. For the porous material, the Knudsen diffusion is taken into account in this study. The chemical- and electrochemical reaction rates depend on temperature, material structure, catalytic activity, degradation and partial pressure among others. It is found that the anode thickness and also the anode pore size need to be optimized to achieve high cell efficiency, when the Knudsen diffusion effects are included.

Sung Ho Cho, Woo Young Yoon

ECS Meeting Abstracts • 2016

Lithium Sulfur (Li-S) battery has a theoretically high specific capacity of 1675 mAh/g, which one of the most promising energy source for electric vehicles (EVs), hybrid electric vehicles (HEVs). However, Li-S batteries have problems resulting from the polysulfides dissolution into the electrolyte, volumetric extension of sulfur and insulating property of elemental sulfur. These causes make the loss of active materials and the capacity fading phenomenon. Even we address the as-mentioned issues, we necessarily encounter the formation of dendrite on the lithium metal anode. In our research, we use a lithium powder as an anode material to suppress the dendritic issue of lithium metal. The examination was conducted by comparing between the lithium foil and lithium powder. The cyclic voltammetry were tested at the scan rate of 0.1mV/s and 0.5mV/s with voltage range of 1.5V to 3.0V. Cells were tested at the current densities of 0.2 C-rate and 0.5 C-rate with 1.7V to 2.8V.

Zheng Li, Tianshou Zhao, Lin Zeng

ECS Meeting Abstracts • 2024

The "hydrogen society" concept has emerged as a response to the increasing demand for carbon-free energy and the aim of achieving "carbon neutrality". Proton exchange membrane fuel cells (PEMFCs) are considered the most promising hydrogen energy utilization units for commercialization, despite facing challenges related to durability and cost. One of the key obstacles is anode reversal, which inevitably occurs during the operation of PEMFC and significantly reduces performance, eventually leading to failure. Therefore, it is essential to investigate the mechanisms that affect anti-reversal performance and find effective strategies to improve reversal tolerance without compromising performance. Two approaches have been put forward. First, we aim to enhance the reversal tolerance of proton exchange membrane fuel cells (PEMFCs) by using polyaniline (PANI) coated carbon as a catalyst support. The PANI coating acts as a protective layer that isolates the carbon from the corrosive environment, resulting in improved anti-reversal performance. Moreover, the PANI coating helps to distribute the catalyst nanoparticles and ionomer uniformly, leading to enhanced polarization. We have tested various carbon supports to confirm the applicability of this coating strategy and optimized the thickness of the PANI coating to avoid any adverse effects on performance. Additionally, we have developed a high-specific-surface-area conductive oxide Ti 4 O 7 as an anode catalyst support to overcome the negative effects of carbon corrosion. By shortening the electron transfer pathway and increasing metal coverage, we have achieved comparable polarization performance to conventional carbon-supported counterparts. Our Ir@IrO x /Pt/Ti 4 O 7 -fabricated RTA has demonstrated approximately ten times longer reversal time (6 hours) and two orders of magnitude lower degradation rate than the conventional carbon-supported counterpart. These systematic studies aim to promote the development of highly durable and reversal-tolerant anodes, providing a promising outlook for practical, high-performance, low-degradation, and cost-effective RTA fabrication.

O. Horner, D. P. Wilkinson, E. L. Gyenge

Journal of The Electrochemical Society • 2024

Seawater electrolysis suffers from many issues that must be resolved before the technology can be scaled. The corrosive hypochlorite formation at the anode can damage the electrode and other electrolyzer components. Furthermore, hypochlorite is unstable and can decay, particularly when exposed to heat and metal ions, which could lead to erroneously high oxygen evolution reaction (OER) selectivity calculations in catalyst benchmarking experiments, resulting in poor catalyst and electrolyzer component selection. In this study, we used the rotating ring-disc electrode (RRDE) technique for the characterization of IrO 2 , NiO, Co 3 O 4 , RuO 2 , Pt/C, and PtRu electrocatalysts at near-neutral pH (8.4) in 0.5 M NaCl. The RRDE can overcome the challenge posed by thermocatalytic hypochlorite decay. IrO 2 and PtRu were also studied over a range of chloride concentrations from 0.1 to 1 M. Our findings reveal that elevated temperatures (313 and 333 K) are conducive to higher OER selectivity, as the OER faradaic efficiency (FE) on IrO 2 increased by 23% at 1.22 V vs SHE when the temperature was increased from 293 to 333 K. Increasing the chloride concentration from 0.1 to 1 M increased the OER current density by 40% and 200% on IrO 2 and PtRu, respectively, indicating a synergistic relationship.

Tianyu Cao, Yixiang Shi, Ningsheng Cai

ECS Meeting Abstracts • 2015

Liquid antimony is considered to be a promising anode for direct carbon fuel cell. The pilot system built in this research is made up with fuel supplement unit, cooling sub-system and power generating core block with tubular SOFC (solid oxide fuel cell) planted into liquid antimony bath. The metal bath serves as anode of direct carbon fuel cell and shall be fluidized during fuel cell operation. The fluidize wind acts as a carrier as well as a stirrer, for it carries pulverized coal directly into liquid antimony bath to feed the fuel cell before mixing the coal up with antimony anode. Well-stirred fluidized anode promotes the fuel cell performance, enhancing heat and mass transfer in the anode region, reducing the risk of thermal shock of tubular SOFC as well as accelerating the electrochemical oxidation of carbon fuel at the same time. The system exhibits stable performance during operation, and well-designed setup of liquid metal bath makes it much easier for stack assembly and system scale up, on the other hand, continuous fuel supply procedure employed in this system will also inspire direct carbon fuel cell operation in its future application. Figure 1

Tianyu Cao, Yixiang Shi, Ningsheng Cai

ECS Meeting Abstracts • 2017

Liquid tin has been widely employed as anodes in SOFCs to digest carbonaceous fuels. Liquid tin anode SOFCs fed on methane, kerosene, and carbon black have been successfully constructed and operated. However, the formation of a SnO 2 blocking film at electrochemical reactive sites hinders further electrochemical reaction and impedes steady power generation of the fuel cell system. Here we manage to suppress the formation of isolating SnO 2 film by anode fluidization. Tubular liquid tin anode SOFC has been fabricated and tested in present work. Fuels (H 2 and simulated syngas with different H 2 /CO ratio) are supplied to the electrochemical reactive interface between the anode and the electrolyte via a manner of bubbling bed. H 2 was found to effectively reduce SnO 2 formed when the SOFC was discharged at a constant potential of 0.45V, and anode fluidization has doubled the fuel cell’s power output. We anticipate that anode fluidization in this study will principally simplify the configuration of liquid tin anode SOFC and maintain the stable operation of the fuel cell system. Figure 1

Long Cheng, Yaxin Zhang, Dandan Li et al.

Advanced Functional Materials • 2026

Abstract Fast charging of high‐loading graphite anodes in lithium‐ion batteries (LIBs) is hampered by sluggish Li + ion transport kinetics, leading to detrimental Li dendrite formation and safety hazards. Herein, a copper‐based metal‐organic framework (Cu‐MOF) functionalized hydroxyapatite/bacterial cellulose (Cu‐MOF@HB) composite nanofibers separator is designed to address these critical challenges. The hierarchical porous structure of the Cu‐MOF@HB separator enhances electrolyte wettability and adsorption. Density functional theory (DFT) calculation reveals that abundant open metal sites within the Cu‐MOF promote PF 6 − anion immobilization via Lewis acid‐base interactions, effectively increasing the Li + ion transference number and facilitating faster Li + ion migration within the separator. Consequently, the Cu‐MOF@HB separator effectively mitigates concentration polarization at the graphite anode/separator interfaces, suppressing Li dendrite formation and improving Coulombic efficiency. This significantly improves fast‐charging performance in high‐loading LiFePO 4 (15.5 mg cm −2 )||graphite (7.5 mg cm −2 ) batteries, achieving 79% capacity retention after 600 cycles at 3 C, compared to only 16% with a conventional polypropylene (PP) separator. Critically, the Cu‐MOF@HB separator also exhibits exceptional thermal stability and flame retardancy, enhancing battery safety. This work highlights the significant potential of interfacial engineering of separators, particularly through the incorporation of functional MOFs and thermally stable inorganic nanofibers, for achieving safe and high‐performance fast‐charging LIBs.

Rodney G. Powers, Ivan R. Lasa, Michael T. Mather

CORROSION 2012 • 2012

Abstract Embedded sacrificial zinc anodes have emerged as a promising means of enhancing the durability of repairs to corrosion-deteriorated concrete structures. Sacrificial zinc anodes are encased in grout materials that are formulated with the intent of maintaining the zinc anode in an electrochemically active state. These grouts typically contain salts or humectants comprised of high pH media. Research has shown these grout additives to be capable of activating the zinc anode only on a limited, short-term basis. This paper discusses laboratory testing of a highly conductive proprietary grout material that has demonstrated capability to maintain long-term an electrochemically active state for both encapsulated zinc point anodes for localized repairs, and also in laminated surface-applied panels for large scale protection in either wet or dry zones.

Mani Pujitha Illa, Chandra Shekhar Sharma, Mudrika Khandelwal

ECS Meeting Abstracts • 2020

An ever increasing demand for high energy and high power rating Lithium-ion batteries (LIB) for electric hybrid vehicles persuaded the development of novel electrode materials with large storage capability and faster kinetic process. Carbon nanomaterials, owing to their unique and tunable physical and chemical properties, have been widely investigated as anode materials for LIBs. Diversified strategies involving the synthesis of carbon materials with hierarchical structures (morphology and porosity), and heteroatom doping have shown significant improvement in electrochemical performance of these carbon nanomaterials. In consideration to this, we hereby demonstrate the synthesis and utilization of hierarchical nitrogen-doped porous carbon structures derived from bacterial cellulose-polyaniline nano-composites as a promising anode material for LIBs. Microstructural analysis of the derived carbon revealed the inheritance of fibrous backbone as obtained from bacterial cellulose along with nano-granular structure of polyaniline. The structural and electrochemical properties of as-derived porous carbon structures are analysed systematically by performing XRD, Raman spectroscopy, XPS, cyclic voltammetry, galvanostatic charge/discharge studies and impedance spectroscopy. These results unveiled significantly large reversible capacities of 432, 233, and 127 mAh/g at 1, 5, and 10 C-rate respectively with excellent capacity retention. The energy and power densities of these hierarchical porous carbon structures were increased by 54% and 41% respectively when compared to pure bacterial cellulose derived carbon. This enhanced electrochemical performance may be attributed to the combined effect of interconnected micro-meso porous network of hard carbon along with nitrogen doping. The core-shell structure of this derived carbon accommodates the volume changes during lithium-ion insertion and de-insertion, rendering excellent cyclic stability even at high C rates without causing pulverization.