Minghui Wu, J. Sadhukhan, R. Murphy et al.

The International Journal of Life Cycle Assessment • 2023

Purpose Carbon fibre-reinforced composite materials offer superior mechanical properties and lower weight than conventional metal products. However, relatively, little is known about the environmental impacts and economic costs associated with composite products displacing conventional metal products. The purpose of this study is to develop an integrated life cycle assessment and life cycle costing framework for composite materials in the aviation industry. Methods An integrated life cycle assessment (LCA) and life cycle costing (LCC) framework has been developed. The displacement of a conventional aluminium door for an aircraft by a composite door is presented as an example of the use of this framework. A graphical visualisation tool is proposed to model the integrated environmental and economic performances of this displacement. LCA and LCC models for composite applications are developed accordingly. The environmental hotspots are identified, and the sensitivity of the environmental impact results to the different composite waste treatment routes is performed. Subsequently, the research suggests a learning curve to analyse the unit price for competitive mass production. Sensitivity analysis and Monte Carlo simulation have been applied to demonstrate the cost result changes caused by data uncertainty. Results Energy consumption was the hotspot, and the choice of composite waste treatment routes had a negligible effect on the LCA outcomes. Concerning the costs, the most significant cost contribution for the unit door production was labour. The future door production cost was decreased by about 29% based on the learning curve theory. The uncertainties associated with the variables could lead to variations in the production cost of up to about 16%. The comparison between the two doors shows that the composite door had higher potential environmental impacts and cost compared to the conventional aluminium door during the production stage. However, the composite door would have better environmental and financial performance if a weight reduction of 47% was achieved in future designs. Conclusions The proposed framework and relevant analysis models were applied through a case study in the aerospace industry, creating a site-specific database for the community to support material selection and product development. The graphical tool was proved to be useful in representing a graphical visualisation comparison based on the integration of the LCA and LCC results of potential modifications to the composite door against the reference door, providing understandable information to the decision-makers.

Benedikte Wrålsen, R. O'Born

The International Journal of Life Cycle Assessment • 2023

Purpose The purpose of this study is to advance and illustrate how life cycle assessment (LCA) can assess circular economy business models for lithium-ion batteries to verify potential environmental benefits compared to linear business models. Scenarios for battery repurpose are assessed to support future decision-makers regarding the choice of new versus second life batteries for stationary energy storage. A procedure to determine the substitution coefficient for repurpose and reuse of batteries is proposed. Methods Two different circular economy business models are assessed by applying primary data from two Norwegian companies for the development of a new life cycle inventory. With this new data, the authors compare second life battery (from first life in electric vehicle) scenarios and avoided production potential by performing a complete consequential LCA. Building on earlier work, a procedure to identify the substitution coefficient (i.e., potential for avoided production) for battery life cycle assessments is proposed. Interviews during factory visits were performed to identify a technical and a market factor affecting the substitution coefficient. Results and discussion This study illustrates how life cycle assessment methodology can detect and thus enhance the potential environmental benefits and trade-offs of circular economy business models. Results show that the CBMs which use second life batteries correspond to 16% (for global warming potential) of manufacturing a new battery. This means that a second life battery must avoid > 16% production of a new battery to become the preferred alternative. Hence, circular economy business models with second life batteries can generate net environmental benefits while the remaining battery capacity and market price are identified factors that can alter the potential environmental benefits. The findings suggest that assumptions concerning the avoided production emissions are crucial for understanding the overall impacts of battery value chains. Conclusions Circular economy business models which enable second life batteries show lower environmental impacts compared to a new battery when it can partly avoid production of a new battery. Based on the identified technical and market factor affecting this potential, a key message to industry and other organizations is that second life batteries should be chosen over new batteries. This depends on the remaining capacity being satisfactory for the new application, and the investment is not performed because of a low price compared to a new battery. Consequential LCA practitioners adopting a market approach while evaluating battery reuse and repurpose should model and account for the avoided production potential.

N. Alaux, H. Vašatko, D. Maierhofer et al.

The International Journal of Life Cycle Assessment • 2023

Purpose Bio-based insulation materials are one of the most promising solutions for reducing the environmental impacts of building envelopes. Among these materials, the environmental benefits of mycelium-based materials have merely been investigated, despite their promising technical and thermal properties. In this paper, we perform a first prospective cradle-to-grave life cycle assessment (LCA) of mycelium-based composite blocks. Methods An attributional cradle-to-gate LCA of the laboratory production of mycelium-based composites was first performed, including 11 environmental impact indicators. Then, scenarios were defined to scale up the technology to the level of industrial production, including the remaining life cycle modules to perform a cradle-to-grave analysis. Biogenic and metabolic carbon were considered by applying the static −1/+1 approach and following the current LCA standards. Future-oriented energy and transport mixes were also included as an additional scenario, systematically modifying both the foreground and background data. Finally, the industrially scaled-up technology and alternative insulation materials were compared with these future conditions (as applied to both materials). Results and discussion Considering climate change, the results are encouraging in comparison to those for traditional plastic insulation, but do not necessarily surpass those for other existing materials such as rock wool. However, trade-offs are observed in other indicators, for which mycelium-based composites tend to perform worse than traditional insulation materials. The industrial scale-up reduced impacts for most indicators, but a considerable trade-off was observed with regard to terrestrial ecotoxicity. The main driver for the remaining greenhouse gas (GHG) emissions was found to be the electricity use during the manufacturing phase. We consider the inclusion of the other life cycle stages as relevant, as this increased the GHG emissions by 10%. Limitations of the current LCA standards, however, are noted and discussed, especially regarding the cascading use of biogenic materials, and highlight the relevance of this case study. Conclusions Mycelium-based composites show a potential for future development, but careful attention should be paid to reducing electricity needs in their manufacturing process. Further improvements could also be made by using fast-growing biogenic materials as a substrate. In particular, we encourage researchers to include all of the life cycle stages in future studies, especially if biogenic emissions are considered.

Tom Bradley, M. Rajaeifar, A. Kenny et al.

The International Journal of Life Cycle Assessment • 2023

Purpose Microalgae-derived biofuels are considered a low-carbon alternative to fossil fuels. Nevertheless, as with all biofuels, there is still uncertainty around their sustainability. Most life cycle assessments (LCA) of microalgae biofuels so far used lab-based, scaled-up lab experimental data or data from the scientific literature. This article, provides evidence and analysis, undertaking an LCA using real-world data from an industrial facility that uses a combination of photobioreactor and fermenter systems. Methods The current well-to-wheel LCA study aimed to compare the environmental impacts of microalgae biodiesel production—under different energy regimes—and with petroleum-derived diesel. The functional unit was considered as “combustion of 1 MJ (Lower Heating Value) of algal biodiesel in an internal combustion engine (as B100)”. This LCA study considers the environmental and energy impacts from the construction of the facility, as well as those impacts from the operation of the facility. The foreground LCI data was collected from a real-world one-hectare microalgae production pilot facility. ReCiPe, IPCC AR5 (GWP100 and GWP20) and Global Temperature Potential (GTP) were implemented to assess the life cycle environmental impacts. Results and discussion The assessment shows that when infrastructure is included, microalgae-derived biofuels are not yet favourable over petroleum-derived fuels on GWP100, and this becomes worse over shorter timescales. In terms of climate change (GWP100), whilst 1 MJ (LHV) of fossil-derived diesel would emit 8.84 × 10^−2 kg CO_2eq, 1 MJ of microalgae-derived biodiesel from a solar photovoltaic powered facility would emit 1.48 × 10^−1 kg CO_2eq. To be equal to petroleum-derived diesel in terms of GWP100, or perform better, productivity of the microalgae production system needs to be improved as the most effective solution. The results also showed that electricity and infrastructure were major sources of environmental impacts, as well as the yeast used within the fermenter. Moreover, it takes 0.99 MJ of direct energy per 1 MJ of microalgae biofuel produced, similar to the fossil fuel industry for 1 MJ of diesel. Conclusions Using infrastructure and operational models, the study shows that the facility does not compare well with petroleum-derived diesel unless productivity can be increased. Productivity improvements, be it through improvements to microalgae strains or improved photobioreactor designs, should be a priority to ensure microalgae become a sustainable fuel feedstock. Electricity use should be reduced as well, again, through improved cultivation system designs. In terms of the current system, the high impacts of yeast should be addressed, either through co-locating yeast production or through ensuring specific sources with lower impacts. Extracting lipids will effectively waste some high-value products, whilst the waste can be expected to be a mixture of unextracted lipids, polysaccharides or fibre, some proteins and minerals. It is also shown that harmonisations of the assessments are needed for future studies and real-world operation facilities to conclusively decide if microalgae should be used as fuel or if they would be better used for other products, such as feed or high-value products.

Berfin Bayram, K. Greiff

The International Journal of Life Cycle Assessment • 2023

Purpose Life cycle assessment (LCA) is increasingly being applied to construction and demolition waste (CDW) recycling. But what is the current state of LCA studies on CDW recycling? In the context of circular economy, several aspects become important in LCA, such as avoided impacts and consideration of the quality of recycled materials. The aim of this study is to identify inconsistencies and best practices, and then provide recommendations for future LCA studies focusing on CDW recycling. Methods We conducted a systematic literature review on 76 journal articles. First, a general mapping of the selected studies was performed including the temporal and geographical distribution, and a bibliometric analysis to capture the linkages between the studies. Within the LCA content-based analysis, an in-depth assessment of three important quality aspects: (1) quality of the study based on the applied LCA methodology, (2) inclusion of material quality in LCA, and (3) data quality considering sensitivity and uncertainty analyses, was carried out. Major LCA components such as functional unit (FU), software, database, system approach (attributional or consequential), allocation method, life cycle impact assessment, and interpretation were evaluated. A special emphasis was placed on avoided impacts and the inclusion of recycled material quality in the LCA. Results and discussion In this review, it was found that many essential elements of LCA were missing or not implemented correctly. For example, in the definition of FU, some studies did not mention any FU, others defined an invalid FU, and most of the studies defined a uniform FU, which was most likely confused with the reference flow. The main problem observed is the lack of transparent reporting on the different elements of LCA. Regarding avoided impacts, for instance, only 13 studies reported the avoided materials and their substitution coefficients. Also, 6 studies used the term “virgin material” for avoided impacts without further information, which is a very broad term and difficult to interpret. Furthermore, only 12 studies included the quality of recycled material in the LCA. Conclusion To obtain reliable LCA results, the practitioners should follow the principal LCA methodology and peer-reviewers should ensure the proper implementation. In CDW recycling, the differentiation between downcycling and recycling is essential; therefore, the quality of recycled materials should be included in the LCA. Considering inconsistent implementation of avoided impacts, a standardized and well-defined avoided impact framework is suggested to be developed to improve the quality and reliability of future LCA studies.

Rickard Arvidsson, Magdalena Svanström, Björn A. Sandén et al.

The International Journal of Life Cycle Assessment • 2023

Some future-oriented life cycle assessment (LCA) terms, particularly prospective and ex-ante, show notable increase in use in publications over the last decade. However, scholars have pointed out that it is currently unclear exactly what these terms mean and how they are related. This paper aims to explain defining differences between future-oriented LCA terms and provide terminology recommendations. Existing definitions of future-oriented LCA terms were reviewed and analyzed. Workshops were held where defining differences of future-oriented LCA terms were discussed. Temporal positionality and technology maturity appear to be two critical aspects of future-oriented LCA. Prospective and ex-ante LCA are similar, with the possible difference that ex-ante LCA always involves an increase in technology maturity in the future. Considering the notable similarities, it seems reasonable to converge terms to mitigate field fragmentation and avoid terminology confusion. To denote LCA studies with a future temporal positionality, we recommend using the term prospective LCA, defined as “LCA that models the product system at a future point in time relative to the time at which the study is conducted”. Furthermore, since technology maturity is clearly a critical aspect for prospective LCA, we recommend prospective LCA studies to clearly define the maturity of the technologies modeled in the production system.

P. Holzapfel, Vanessa Bach, M. Finkbeiner

The International Journal of Life Cycle Assessment • 2023

Purpose In grid electricity consumption models, the location-based method uses regional average emission factors to account for environmental impacts. The market-based method is based on contractual agreements, verifying the exclusive claim on electricity from specific energy sources. An inconsistent application of these methods in life cycle assessment (LCA) and GHG accounting can lead to double counting. Especially, double counting electricity associated with rather low environmental impacts, such as renewable energy, might lead to impact underestimations. The aim of this paper is to identify, describe and propose solutions to double counting challenges. Methods A four-step procedure is carried out. First, the specifications on grid electricity mix selection in frequently applied standards for LCA and GHG accounting are analysed. Besides the ISO norms for LCA (14040/44) and carbon footprinting (14064/67), the GHG Protocol and the Product and Organizational Environmental Footprint (PEF/OEF) are considered. Based on this analysis, challenges of double counting electricity from specific sources are identified. In the third step, potential solutions for avoiding double counting are proposed. The last research step consists of an illustrative case study to demonstrate the calculation of market-based electricity mixes and identify potential adjustments necessities for LCA application. Results and discussion A parallel application of the location-based and the market-based method poses the main double-counting challenge. Thus, avoiding double counting demands consistent method application throughout the whole life cycle. Whereas this is relatively straightforward for the location-based method, consistent market-based method application is more challenging. LCAs rely on average life cycle inventory processes, which mostly include location-based electricity mixes. However, for consistent market-based method application throughout the life cycle, electricity-related environmental impacts in the inventory system also need to be market-based. This would demand a partial recalculation of LCI datasets using market-based residual electricity mixes. Besides illustrating the calculation of market-based electricity mixes, the case study is used to identify and propose solutions for two main challenges for residual mix application in LCA: countries without residual mix and electricity under a double marketing ban. Conclusion Double counting of electricity from specific energy sources is a challenge, since it can lead to under- or overestimations of environmental impacts. Both the location-based and market-based method can avoid double counting. However, parallel or inconsistent applications of both methods lead to double counting. In order to avoid double counting, there is a need to enable and use consistent electricity accounting rules in LCA and GHG accounting.

Pelle Sinke, Elliot W Swartz, Hermes Sanctorum et al.

The International Journal of Life Cycle Assessment • 2023

Purpose Cultivated meat (CM) is attracting increased attention as an environmentally sustainable and animal-friendly alternative to conventional meat. As the technology matures, more data are becoming available and uncertainties decline. The goal of this ex-ante life cycle assessment (LCA) was to provide an outlook of the environmental performance of commercial-scale CM production in 2030 and to compare this to conventional animal production in 2030, using recent and often primary data, combined with scenario analysis. Methods This comparative attributional ex-ante LCA used the ReCiPe Midpoint impact assessment method. System boundaries were cradle-to-gate, and the functional unit was 1 kg of meat. Data were collected from over 15 companies active in CM production and its supply chain. Source data include lab-scale primary data from five CM producers, full-scale primary data from processes in comparable manufacturing fields, data from computational models, and data from published literature. Important data have been cross-checked with additional experts. Scenarios were used to represent the variation in data and to assess the influence of important choices such as energy mix. Ambitious benchmarks were made for conventional beef, pork, and chicken production systems, which include efficient intensive European animal agriculture and incorporate potential improvements for 2030. Results and discussion CM is almost three times more efficient in turning crops into meat than chicken, the most efficient animal, and therefore agricultural land use is low. Nitrogen-related and air pollution emissions of CM are also lower because of this efficiency and because CM is produced in a contained system without manure. CM production is energy-intensive, and therefore the energy mix used for production and in its supply chain is important. Using renewable energy, the carbon footprint is lower than beef and pork and comparable to the ambitious benchmark of chicken. Greenhouse gas profiles are different, being mostly CO_2 for CM and more CH_4 and N_2O for conventional meats. Climate hotspots are energy used for maintaining temperature in reactors and for biotechnological production of culture medium ingredients. Conclusions CM has the potential to have a lower environmental impact than ambitious conventional meat benchmarks, for most environmental indicators, most clearly agricultural land use, air pollution, and nitrogen-related emissions. The carbon footprint is substantially lower than that of beef. How it compares to chicken and pork depends on energy mixes. While CM production and its upstream supply chain are energy-intensive, using renewable energy can ensure that it is a sustainable alternative to all conventional meats. Recommendations CM producers should optimize energy efficiency and source additional renewable energy, leverage supply chain collaborations to ensure sustainable feedstocks, and search for the environmental optimum of culture medium through combining low-impact ingredients and high-performance medium formulation. Governments should consider this emerging industry’s increased renewable energy demand and the sustainability potential of freed-up agricultural land. Consumers should consider CM not as an extra option on the menu, but as a substitute to higher-impact products.

Irini Barbero, Y. Rezgui, T. Beach et al.

The International Journal of Life Cycle Assessment • 2024

While social aspects are considered as part of Life Cycle Sustainability Assessment (LCSA), the concept of Social Life Cycle Assessment (S-LCA) is relatively new in the construction sector, and more research is needed to comprehend its full potential and inform practice to deliver socially sustainable interventions. The paper aims to provide an account of current work in the field of S-LCA in the construction sector and presents an overview of the methodologies and frameworks that are currently used, with a focus on the critical analysis of impact categories applied to the construction sector. The paper adopts a systematic review of the literature with the objective to (a) provide a holistic and cross-disciplinary overview of the S-LCA methodologies and frameworks in the construction sector, (b) explore existing gaps, and (c) frame directions for future research. Several gaps have been identified in relation to the S-LCA research landscape applied to the construction sector, which have, in turn, informed the formulation of recommendations for future research. The paper emphasises the importance and the need to intensify efforts to develop and reach consensus on the categories and criteria to deliver an S-LCA framework for Social Life Cycle Assessment of built environments. The framework, underpinned by a methodology, should involve an adaptable weighting system that considers the nature of the building as well as the type and profile of occupants. It should also factor in dynamic data to inform real-time adaptations to continuously deliver socially sustainable built environment interventions.

A. Shabib, M. Abdallah, A. Shanableh et al.

International Journal of Environmental Science and Development • 2021

Bio-electrochemical anaerobic digestion (AD) is one of the most recent advancement in anaerobic treatment processes. Microbial electrolysis cells (MECs) are used for bio-electrochemical treatment, where the supplied external power is used to enhance the performance of AD. Multiple studies have investigated the viability of MECs under various operating parameters and for different organic wastes. The present paper aims at reviewing the latest literature regarding bio-electrochemical enhanced AD through MECs. It was concluded that MEC reactors significantly enhance AD performance under different supplied voltages, temperatures, electrodes configuration, as well as other operating parameters. Based on the compiled literature, further comprehensive life cycle assessment of MECs is recommended prior to any full-scale implementation.

J. Streeck, Christoph Hank, M. Neuner et al.

Green Chemistry • 2018

Herein, a techno-economic and environmental performance evaluation (i.e. Life Cycle Assessment (LCA)) of a 45 kW Microbial Electrolysis Cell (MEC) system is presented in the context of industrial wastewater remediation. This system produces H2 and CO2 – suitable for downstream CH3OH synthesis – based on the bio-electrochemical conversion of chemical industry wastewater with an organic content of 3.9 g(COD) L−1. A cost–benefit analysis indicates that the MEC system hardware costs, share of CO2 captured from the MEC and MEC operating current density (i.e. 1.0 mA cm−2) are crucial parameters influencing the total cost and represent areas for potential cost reductions. It was established based on the present study that MEC system operation with renewable electricity leads to H2 production costs of 4–5.7€ kg(H2)−1 (comparable to H2O electrolysis) and CH3OH production costs of 900€ t(CH3OH)−1. At the current CH3OH market prices, however, the production is currently not profitable. In turn, the cost-efficient construction of the MEC system and the use of less expensive materials could lead to improved CH3OH production economics based on this route. Our results indicate that the use of low-cost materials has greater potential with regard to cost reduction compared to reducing the internal resistance and polarization losses via the use of expensive high-performance materials in MEC construction. A complementary LCA of the proposed system, based on a “cradle-to-gate” definition, indicates that waste-based is superior to fossil-based CH3OH production with respect to global warming potential and cumulated fossil energy demand, provided the system is operated with 100% renewable electricity and CO2 sourced only from the MEC. However, with regard to the impact categories Metal Depletion and Freshwater Eutrophication Potential, the system was found to perform less satisfactorily (i.e. in comparison with fossil-based CH3OH production).

Seçil TUTAR ÖKSÜZ

Sakarya University Journal of Science • 2022

Bioelectrochemical systems (BESs) use electrochemically active microorganisms to convert the chemical energy of organic matter into electrical energy, hydrogen, or other useful products through redox reactions. Microbial electrolysis cell (MEC) is one of the most common BESs which are able to convert organic substrate into energy (such as hydrogen and methane) through the catalytic action of electrochemically active bacteria in the presence of electric current and absence of oxygen. In the past decades, BESs have gained growing attention because of their potential, but there is still a limited amount of research is done for the environmental effects of BESs. This study initially provides an update review for MECs including general historical advancement, design properties, and operation mechanisms. Later, a life cycle assessment (LCA) study was conducted using a midpoint approach, which is TRACI methodology with EIO-LCA model to identify the potential impacts to the environment whether adverse or beneficial using the MECs to produce hydrogen with domestic wastewater as a substrate. The results show that the cumulative negative impacts were substantially larger than the positive impacts by contrast with the expectations, and the cumulative output data show that human health non-cancer impact provides the highest environmental effects than others mainly because of the inorganic chemicals, pumping and wastewater recycling equipment step. In addition, global warming potential and smog creation potential are also elevated mainly due to electricity usage, inorganic chemical and glassware reactor production. Later we are externally normalized each impact category to compare the results at the normalization level, and we again found that human health (cancer or non-cancer) potential provides the most negative impact on the environment in the MEC system originates on human health indicators.

Pietro Goglio, G. Brankatschk, M. T. Knudsen et al.

The International Journal of Life Cycle Assessment • 2018

PurposeThe focus of the life-cycle assessment (LCA) of an agricultural plant product is typically on one crop. However, isolating one crop from the cropping system that it belongs to is often challenging because the crops are often interlinked with the other crops in the cropping system. The main objectives of this discussion article are as follows: (i) to discuss the characteristics of cropping systems which might affect the LCA methodology, (ii) to discuss the advantages and the disadvantages of the current available methods for the life-cycle assessment of cropping systems, and (iii) to offer a framework to carry out LCA of crops and cropping systems.MethodsThe definition of cropping systems is provided together with a description of two types of LCA: product LCA and system LCA. The LCA issues related to cropping system characteristics have been classified as (1) crop interrelationship, (2) crop management and emissions, and (3) functional unit issues. The LCA approaches presented are as follows: cropping system, allocation approaches, crop-by-crop approach, and combined approaches. The various approaches are described together with their advantages and disadvantages, applicability, comprehensiveness, and accuracy.Results and discussionThe cropping system approach is best suited for system LCA. For product LCA, none of the methods is fully exhaustive and accurate. The crop sequence approach takes into consideration the cropping system issues, if they happen within the year or season, and cannot be applied for intercropping and agroforestry systems. The allocation approaches take into account the cropping system effects by establishing a mathematical relationship between crops present in the cropping systems. The model for integrative life-cycle assessment in agriculture (MiLA) approach considers cropping system issues if they are related to multiproduct and nutrient cycling, while the crop-by-crop approach is highly affected by assumptions and considers cropping system issues only if they are related to the analyzed crop.ConclusionsEach LCA approach presents advantages and disadvantages. For system LCA, the cropping system approach is recommended. For product LCA, environmental burdens should be attributed applying the following hierarchy: (1) attributed to the crop if based on a clear causality, (2) attributed with combined approaches and specific criteria, and (3) attributed with allocation approaches and generic criteria. These approaches should be combined with the cropping system approach..

R. Rosenbaum, A. Antón, Xavier Bengoa et al.

The International Journal of Life Cycle Assessment • 2015

PurposePesticides are applied to agricultural fields to optimise crop yield and their global use is substantial. Their consideration in life cycle assessment (LCA) is affected by important inconsistencies between the emission inventory and impact assessment phases of LCA. A clear definition of the delineation between the product system model (life cycle inventory—LCI, technosphere) and the natural environment (life cycle impact assessment—LCIA, ecosphere) is missing and could be established via consensus building.MethodsA workshop held in 2013 in Glasgow, UK, had the goal of establishing consensus and creating clear guidelines in the following topics: (1) boundary between emission inventory and impact characterisation model, (2) spatial dimensions and the time periods assumed for the application of substances to open agricultural fields or in greenhouses and (3) emissions to the natural environment and their potential impacts. More than 30 specialists in agrifood LCI, LCIA, risk assessment and ecotoxicology, representing industry, government and academia from 15 countries and four continents, met to discuss and reach consensus. The resulting guidelines target LCA practitioners, data (base) and characterisation method developers, and decision makers.Results and discussionThe focus was on defining a clear interface between LCI and LCIA, capable of supporting any goal and scope requirements while avoiding double counting or exclusion of important emission flows/impacts. Consensus was reached accordingly on distinct sets of recommendations for LCI and LCIA, respectively, recommending, for example, that buffer zones should be considered as part of the crop production system and the change in yield be considered. While the spatial dimensions of the field were not fixed, the temporal boundary between dynamic LCI fate modelling and steady-state LCIA fate modelling needs to be defined.Conclusions and recommendationsFor pesticide application, the inventory should report pesticide identification, crop, mass applied per active ingredient, application method or formulation type, presence of buffer zones, location/country, application time before harvest and crop growth stage during application, adherence with Good Agricultural Practice, and whether the field is considered part of the technosphere or the ecosphere. Additionally, emission fractions to environmental media on-field and off-field should be reported. For LCIA, the directly concerned impact categories and a list of relevant fate and exposure processes were identified. Next steps were identified: (1) establishing default emission fractions to environmental media for integration into LCI databases and (2) interaction among impact model developers to extend current methods with new elements/processes mentioned in the recommendations.

T. Nemecek, Andreas Roesch, M. Bystricky et al.

The International Journal of Life Cycle Assessment • 2023

Agricultural production, which dominates the environmental impacts of the food sector, has specific characteristics that need to be considered in life cycle assessment (LCA) studies. Agricultural systems are open, difficult to manage and control, strongly depend on natural resources and their impacts are highly variable and influenced by soil, climate and farm management. A specific framework, efficient methods and tools are thus needed to adequately assess the environmental impacts of agricultural systems. We present the Swiss Agricultural Life Cycle Assessment (SALCA) concept and method, developed for a detailed and specific analysis of agricultural systems. It comprises rules for the definition of system boundaries, functional unit and allocation, emission models, a life cycle inventory (LCI) database, calculation tools, impact assessment methods and concepts for analysis, interpretation and communication. This paper focuses on emission models for gaseous N, nitrate leaching, P emissions to water, soil erosion, pesticides, heavy metals, emissions from animal production and impact assessment methods for soil quality and biodiversity. The models are calculated at the crop, field, animal group and farm levels and are integrated in a consistent and harmonised framework, which is ensured by exchanging intermediate results between models. The SALCA concept has been applied in numerous LCA studies for crops and crop products, cropping systems, animal husbandry systems and animal products, food and feed products, farms and product groups, the agrifood sector and food systems. The SALCA methodology has also been a backbone of the LCI databases ecoinvent, AGRIBALYSE and the World Food LCA database. The strengths of SALCA lie in its comprehensiveness, specificity to agriculture, harmonisation, broad applicability, consistency, comparability, flexibility and modularity. The extensive data demand and the high complexity, however, limit the application of SALCA to experts. The geographical scope is limited to Central and Western Europe, with a special focus on Switzerland. However, due to the modular and flexible design, an adaptation to other contexts is feasible with reasonable effort. SALCA enables answering a wide range of research questions related to environmental assessment and is applicable to various goals and scopes. A further development would be the inclusion of the social and economic dimensions to perform a full sustainability analysis in the SALCAsustain framework.

Olatunde Akinbuja, Sharon Velasquez Orta, Kamelia Boodhoo

The International Journal of Life Cycle Assessment • 2025

Abstract Purpose In this work, a life cycle assessment (LCA) was conducted to compare the environmental impacts of a microbial fuel cell (MFC) using a biotic cathode based on graphite/ Chlorella vulgaris microalgae against using a conventional abiotic platinised titanium (Pt-Ti) or graphite cathode. Methods Electrode production, microalgae production, and MFC operation were key parameters of interest in the LCA. Indices adopted for comparing environmental burdens include global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP), among others. Results and discussion Abiotic graphite cathode in a microbial fuel cell exhibited the lowest environmental burden. Replacing the titanium with graphite in the abiotic platinised titanium cathode reduced GWP by 99%. The microbial fuel cell operation itself had an insignificant contribution to the environmental burden. However, the microalgae cultivation and harvesting unit operations had negative environmental indices. AP and EP of the Pt-Ti and abiotic graphite scenarios are generally low (ca. 10 −5 units) and insignificant. The fertiliser added during microalgae cultivation contributed significantly to AP and EP. Using wastewater to cultivate the Chlorella vulgaris reduced, but did not eliminate, the overall environmental burden compared to using fertiliser. Conclusion The results suggest that using pre-cultivated microalgae in the cathode of an MFC does not further reduce the overall environmental burden compared with using a conventional graphite-aerated cathode electrode unless cultivation emissions are assigned to a dual wastewater treatment process. As such, the environmental benefits of using microalgae in MFC operation are only realised if microalgae are cultivated for wastewater remediation.

Ludovic Jourdin

International Chain Elongation Conference 2020 • 2020

Contribution to the International Chain Elongation Conference 2020 | ICEC 2020.

Ming-Yan Shen, Vannasinh Souvannasouk, Sasithorn Saipa et al.

Research Square • 2023

Abstract Today, about 4.8–12.7 million tons of fossil-based plastics have reached the oceans. Thus, this pollution has become a matter of significant concern globally. Polyhydroxyalcanoates (PHAs) are one of the promising biodegradable plastics that could replace conventional petroleum-based plastics and subsequently mitigate oceanic pollution. High organic wastewater has been examined as a potential substrate for lowering the manufacturing cost of PHAs. This study has found that for a project lifetime of 20 years, the cost of the PHA manufacturing process reached $994,143. The annual process operation cost was $159,711. The payback period was 6.79 years, and the internal return rate was 16%. However, if costs increased by 20%, the benefits decreased by 25%. Since price of PHAs is higher than that of conventional plastic, various supports from the government could potentially push PHAs to the market. Statement of Novelty This study successfully determines the techno-economic analysis of the PHA production to form high-strength waste using MMC as the microbial source. The sensitivity analysis of the system was also performed.

Saad Saleem Khan, Mohsin Amjad, Hussain Shareef et al.

Energy Exploration & Exploitation • 2023

This review presents a techno-economic analysis of microbial fuel cells (MFCs) in the domain of generating sustainable energy and treating wastewater with the aim of attracting investors through research and development for residential and commercial applications. The operation principles and various MFC types, along with their advantages and disadvantages, are thoroughly considered. The efficiency of various MFC types is considered to present appropriate options for commercial applications. However, large-scale integrations face substantial financial limitations owing to the reluctance of investors. This review explores the cost-benefit balance associated with the operation of an MFC system. For encouraging investors, different cost variables, such as the initial investment, operating costs, potential electricity generation, and waste treatment capacity, are thoroughly considered. These variables are placed on the spectrum of a cost-benefit analysis to vitalize the economic feasibility of the MFC technology in various scenarios, considering an order of financial variables. MFC development at an optimized cost is the pivotal pre-requisite to secure a competitive advantage over conventional sources of energy with carbon emissions. Thus, this study is expected to prompt decision-makers to adopt the MFC technology at the commercial level.

Nicholas Miwornunyuie, Samuel O. Alamu, Guozhu Mao et al.

Clean Technologies • 2025

This study systematically compares the environmental and economic performance of three wastewater treatment systems: constructed wetlands (CWs), microbial fuel cells (MFCs), and their integration (CW–MFC). Lab-scale units of each system were constructed using a multi-media matrix (gravel, zeolite, and granular activated carbon), composite native wetland species (Juncus effusus, Iris sp., and Typha angustifolia), carbon-based electrodes (graphite), and standard inoculum for CW and CW–MFC. The MFC system employed carbon-based electrodes and proton-exchange membrane. The experimental design included a parallel operation of all systems treating domestic wastewater under identical hydraulic and organic loading rates. Environmental impacts were quantified across construction and operational phases using life cycle assessment (LCA) with GaBi software 9.2, employing TRACI 2021 and ReCiPe 2016 methods, while techno-economic analysis (TEA) evaluated capital and operational costs. The key results indicate that CW demonstrates the lowest global warming potential (142.26 kg CO2-eq) due to its reliance on natural biological processes. The integrated CW–MFC system achieved enhanced pollutant removal (82.8%, 87.13%, 78.13%, and 90.3% for COD, NO3, TN, and TP) and bioenergy generation of 2.68 kWh, balancing environmental benefits with superior treatment efficiency. In contrast, the stand-alone MFC shows higher environmental burdens, primarily due to energy-intensive material requirements and fabrication processes. TEA results highlight CW as the most cost-effective solution (USD 627/m3), with CW–MFC emerging as a competitive alternative when considering environmental benefits and operational efficiencies (USD 718/m3). This study highlights the potential of hybrid systems, such as CW–MFC, to advance sustainable wastewater treatment technologies by minimizing environmental impacts and enhancing resource recovery, supporting their broader adoption in future water management strategies. Future research should focus on optimizing materials and energy use to improve scalability and feasibility.

Ari Ämmälä, J. Sirviö, O. Laitinen et al.

Cellulose • 2024

Tracking mechanical microfibrillation in nanocellulose production is time-consuming due to a lack of quick characterization methods. This study investigates optical monitoring of the mechanical microfibrillation process by determining the dimensions of microfibrillated cellulose (MFC) particles on micron scale. Bleached hardwood pulp was microfibrillated using three sets of grinding discs in a six-stage pilot process, analyzing MFC characteristics as a function of specific energy consumption via image analysis. A laboratory-scale ultrafine grinder was also used for comparison. The degree of microfibrillation was assessed over a broad energy range using the equivalent diameter derived from the MFC length and width through image processing. The microfibrillation process adhered to Rittinger’s law, i.e., changes in the apparent specific surface area (SSA) were linearly proportional to the applied grinding energy. SSA, being inversely proportional to equivalent diameter, predicted MFC quality in terms of nanofilm strength properties. The optical fiber image analyzer proved suitable for online monitoring and control of microfibrillation processes. Despite resolution limits in detecting sub-micron particles, their proportion interrelates to the size of optically visible particles, covering industrial needs for mechanical microfibrillation.

I. Zekker, G. D. Bhowmick, E. Rikmann et al.

• 2018

Sidestream wastewater was used to maintain autotrophic nitrogen removal in mobile pilot-scale (3 m3 process tanks) reactor configurations -deammonification in biofilm. Biofilms were developed after adaption of biomass on carriers with undiluted liquid effluent of municipal wastewater treatment plant biogas facility. The highest total nitrogen removal rate (TNRR) was achieved in the deammonification biofilm reactor (0.33 kg-N m-3 d-1). Time-based and concentration-based (optimal dissolved oxygen (DO) concentration was 0.3-0.8 mg O2 L-1) aeration control proved reliable when reject water characteristics were relatively stable. The biofilm from deammonification biofilm reactor was then tested in microbial fuel cell (MFC) technology in order to understand the exo-electrogenic behavior of it. Two MFCs with the biofilm (Test) and another one with septic tank mix consortia as control (Control) were observed to be capable of generating continuous bio-energy with operating voltage of 262 ± 17 mV and 163 ± 18 mV for Test and Control, respectively. Test (9.5 W.m-3) showed almost two times higher volumetric power density than Control (4.9 W.m-3) with lower internal resistance of 161 Ω than that of Control (386 Ω). The coulombic efficiency was also found to be higher in case of Test (27.5 ± 1.7 %) than Control (17.7 ± 1.9 %), demonstrating the applicability of ANAMMOX in MFC to achieve efficient wastewater treatment as well as higher energy recovery from MFC. Proper ORP range for biofilm ANAMMOX operation was -200 mV-0 mV.

Dibyojyoty Nath, M. Ghangrekar

Scientific Reports • 2020

Wastewater treatment coupled with electricity recovery in microbial fuel cell (MFC) prefer mixed anaerobic sludge as inoculum in anodic chamber than pure stain of electroactive bacteria (EAB), due to robustness and syntrophic association. Genetic modification is difficult to adopt for mixed sludge microbes for enhancing power production of MFC. Hence, we demonstrated use of eco-friendly plant secondary metabolites (PSM) with sub-lethal concentrations to enhance the rate of extracellular electron transfer between EAB and anode and validated it in both bench-scale as well as pilot-scale MFCs. The PSMs contain tannin, saponin and essential oils, which are having electron shuttling properties and their addition to microbes can cause alteration in cell morphology, electroactive behaviour and shifting in microbial population dynamics depending upon concentrations and types of PSM used. Improvement of 2.1-times and 3.8-times in power densities was observed in two different MFCs inoculated with Eucalyptus-extract pre-treated mixed anaerobic sludge and pure culture of Pseudomonas aeruginosa, respectively, as compared to respective control MFCs operated without adding Eucalyptus-extract to inoculum. When Eucalyptus-extract-dose was spiked to anodic chamber (125 l) of pilot-scale MFC, treating septage, the current production was dramatically improved. Thus, PSM-dosing to inoculum holds exciting promise for increasing electricity production of field-scale MFCs.

K. Tota-Maharaj, P. Paul

International Journal of Energy and Environmental Engineering • 2015

Microbial fuel cell (MFC) technology represents a form of renewable energy that generates bioelectricity from what would otherwise be considered a waste stream. MFCs may be ideally suited to the small island developing state (SIDS) context, such as Trinidad and Tobago where seawater as the main electrolyte is readily available, and economically renewable and sustainable electricity is also deemed a priority. Hence this project tested two identical laboratory-scaled MFC systems that were specifically designed and developed for the Caribbean regional context. They consisted of two separate chambers: an anaerobic anodic chamber inoculated with wastewater and an aerobic cathodic chamber separated by a proton exchange membrane. Domestic wastewater from two various wastewater treatment plants inflow (after screening) was placed into the anodic chamber, and seawater from the Atlantic Ocean and Gulf of Paria placed into the cathodic chambers, respectively, with the bacteria present in the wastewater attached to the anode. Experimental results demonstrated that the bacterial degradation of the wastewaters as substrate induced an electron flow through the electrodes producing bioelectricity whilst simultaneously reducing the organic matter as biochemical oxygen demand and chemical oxygen demand by 30 to 75 %. The average bioenergy output for both systems was 84 and 96 mW/m2, respectively. This study demonstrated the potential for simultaneous bioenergy production and wastewater treatment in the SIDS context.

P. Bosch‐Jimenez, Clara Corbella, Ainhoa Gaudes et al.

Fuel Cells • 2024

Traditional wastewater treatment plants (WWTPs) consume a significant amount of energy to clean wastewater. However, for medium‐ and small‐scale WWTPs, it is crucial to have an energetically self‐sustained treatment. In this regard, novel low‐energy demand treatment systems, such as nature‐based solutions (NBS), are highly suitable alternatives. Constructed wetlands coupled with microbial fuel cells (MFC), referred to as electrowetlands (EWs), are NBS able to treat wastewater while recovering electricity. In this study, initially, various granular carbon materials were tested as anode materials in laboratory‐scale MFCs, and anthracite was selected due to its higher electrochemical activity. Then, pre‐pilot scale tests were conducted, evaluating different EW configurations. The one consisting in a horizontal anode yielded the best wastewater treatment efficiencies (chemical oxygen demand [COD] degradation greater than 90%) and electricity production (11 mW m−2; 260 mWh day−1 m−2). Finally, a 50 m2 pilot was constructed in Valladolid, studying its performance under real conditions for 1 year. The pilot showed robust and stable performance, achieving high wastewater treatment efficiencies (COD degradation >85%, outflow COD of 100 ppm) and generating 115 Wh in 1 year (power density of 0.4 mW m−2).

L. Kiseleva, Sofya K. Garushyants, Hongwu Ma et al.

Journal of Integrative Bioinformatics • 2015

Summary The combined processes of microbial biodegradation accompanied by extracellular electron transfer make microbial fuel cells (MFCs) a promising new technology for cost-effective and sustainable wastewater treatment. Although a number of microbial species that build biofilms on the anode surfaces of operating MFCs have been identified, studies on the metagenomics of entire electrogenic communities are limited. Here we present the results of wholegenome metagenomic analysis of electrochemically active robust anodic microbial communities, and their anaerobic digester (AD) sludge inocula, from two pilot-scale MFC bioreactors fed with different distillery wastewaters operated under ambient conditions in distinct climatic zones. Taxonomic analysis showed that Proteobacteria, Bacteroidetes and Firmicutes were abundant in AD sludge from distinct climatic zones, and constituted the dominant core of the MFC microbiomes. Functional analysis revealed species involved in degradation of organic compounds commonly present in food industry wastewaters. Also, accumulation of methanogenic Archaea was observed in the electrogenic biofilms, suggesting a possibility for simultaneous electricity and biogas recovery from one integrated wastewater treatment system. Finally, we found a range of species within the anode communities possessing the capacity for extracellular electron transfer, both via direct contact and electron shuttles, and show differential distribution of bacterial groups on the carbon cloth and activated carbon granules of the anode surface. Overall, this study provides insights into structural shifts that occur in the transition from an AD sludge to an MFC microbial community and the metabolic potential of electrochemically active microbial populations with wastewater-treating MFCs.

L. Kiseleva, Sofya K. Garushyants, Hongwu Ma et al.

PubMed • 2015

The combined processes of microbial biodegradation accompanied by extracellular electron transfer make microbial fuel cells (MFCs) a promising new technology for cost-effective and sustainable wastewater treatment. Although a number of microbial species that build biofilms on the anode surfaces of operating MFCs have been identified, studies on the metagenomics of entire electrogenic communities are limited. Here we present the results of whole-genome metagenomic analysis of electrochemically active robust anodic microbial communities, and their anaerobic digester (AD) sludge inocula, from two pilot-scale MFC bioreactors fed with different distillery wastewaters operated under ambient conditions in distinct climatic zones. Taxonomic analysis showed that Proteobacteria, Bacteroidetes and Firmicutes were abundant in AD sludge from distinct climatic zones, and constituted the dominant core of the MFC microbiomes. Functional analysis revealed species involved in degradation of organic compounds commonly present in food industry wastewaters. Also, accumulation of methanogenic Archaea was observed in the electrogenic biofilms, suggesting a possibility for simultaneous electricity and biogas recovery from one integrated wastewater treatment system. Finally, we found a range of species within the anode communities possessing the capacity for extracellular electron transfer, both via direct contact and electron shuttles, and show differential distribution of bacterial groups on the carbon cloth and activated carbon granules of the anode surface. Overall, this study provides insights into structural shifts that occur in the transition from an AD sludge to an MFC microbial community and the metabolic potential of electrochemically active microbial populations with wastewater-treating MFCs.

K. Tota-Maharaj, P. Paul

International Journal of Energy and Environmental Engineering • 2015

Microbial fuel cell (MFC) technology represents a form of renewable energy that generates bioelectricity from what would otherwise be considered a waste stream. MFCs may be ideally suited to the small island developing state (SIDS) context, such as Trinidad and Tobago where seawater as the main electrolyte is readily available, and economically renewable and sustainable electricity is also deemed a priority. Hence this project tested two identical laboratory-scaled MFC systems that were specifically designed and developed for the Caribbean regional context. They consisted of two separate chambers: an anaerobic anodic chamber inoculated with wastewater and an aerobic cathodic chamber separated by a proton exchange membrane. Domestic wastewater from two various wastewater treatment plants inflow (after screening) was placed into the anodic chamber, and seawater from the Atlantic Ocean and Gulf of Paria placed into the cathodic chambers, respectively, with the bacteria present in the wastewater attached to the anode. Experimental results demonstrated that the bacterial degradation of the wastewaters as substrate induced an electron flow through the electrodes producing bioelectricity whilst simultaneously reducing the organic matter as biochemical oxygen demand and chemical oxygen demand by 30 to 75 %. The average bioenergy output for both systems was 84 and 96 mW/m2, respectively. This study demonstrated the potential for simultaneous bioenergy production and wastewater treatment in the SIDS context.

Wei-Eng Thung, S. Ong, L. Ho et al.

AIP Conference Proceedings • 2017

Pilot scale up-flow membrane-less microbial fuel cell (UFML-MFC) was constructed to study feasibility of the bioreactor for simultaneous degradation of organic substance and electricity generation. The performance of the UFML-MFC was evaluated with different anode electrode (cube carbon felt and stacked carbon felt) in terms of voltage output, chemical oxygen demand (COD) and Coulombic efficiency (CE). Carbon flake were used as cathode in the UFML-MFC. UFML-MFC was operated in three stages where included batch-fed, end of batch fed and semi-continuous. The Cube carbon felt as anode have the better performance in terms of voltage output and electricity generation in all 3 stages. Maximum voltage output was 0.311 ± 0.004 V at 75% of COD reduction and thus CE was 0.15%. The result shows the operational mode is the key to improve the voltage output and also COD reduction.

P. Hellström, A. Heijnesson-Hultén, M. Paulsson et al.

TAPPI Journal • 2016

Microfibrillated cellulose (MFC) was produced in pilot scale from a bleached birch (Betula verrucosa) kraft pulp that was pretreated with either Fenton's reagent or with a combined mechanical and e ...

Chao Li, Dandan Liang, Yan Tian et al.

Environmental Science & Technology • 2024

To date, dozens of pilot-scale microbial fuel cell (MFC) devices have been successfully developed worldwide for treating various types of wastewater. The availability and configurations of separators are determining factors for the economic feasibility, efficiency, sustainability, and operability of these devices. Thus, the concomitant advances between the separators and pilot-scale MFC configurations deserve further clarification. The analysis of separator configurations has shown that their evolution proceeds as follows: from ion-selective to ion-non-selective, from nonpermeable to permeable, and from abiotic to biotic. Meanwhile, their cost is decreasing and their availability is increasing. Notably, the novel MFCs configured with biotic separators are superior to those configured with abiotic separators in terms of wastewater treatment efficiency and capital cost. Herein, a highly comprehensive review of pilot-scale MFCs (>100 L) has been conducted, and we conclude that the intensive stack of the liquid cathode configuration is more advantageous when wastewater treatment is the highest priority. The use of permeable biotic separators ensures hydrodynamic continuity within the MFCs and simplifies reactor configuration and operation. In addition, a systemic comparison is conducted between pilot-scale MFC devices and conventional decentralized wastewater treatment processes. MFCs showed comparable cost, higher efficiency, long-term stability, and significant superiority in carbon emission reduction. The development of separators has greatly contributed to the availability and usability of MFCs, which will play an important role in various wastewater treatment scenarios in the future.

Blaise William Atkinson

• 1999

General removal of phosphorus (P) from wastewater was introduced in Scandanavia in the late 1960's. At that time it was believed that P alone was limiting to algal growth and that the sole removal of P would solve the problem of eutrophication. However, we now know that both P and nitrogen (N) contribute to this deleterious effect and as such, much research has been conducted concerned with both the biological and chemical removal of these nutrients from sewage effluents. Enhanced biological phosphorus removal (EBPR), which is basically the biological accumulation of soluble P (as polyphosphate or poly-P) from the bulk liquid in excess of normal metabolic requirements, still tends to be sensitive to many external parameters and, as such, is subject to fluctuations. This makes it extremely difficult for wastewater treatment installations to achieve and maintain full compliance with strict discharge regulations. A more comprehensive understanding of the microbial community within the mixed liquor of a wastewater treatment system is therefore required which will ultimately assist in improving system design and performance. Chemical and civil engineers, when designing biological wastewater treatment systems, consider only the processes (biological or chemical) taking place within the reactor/s with little or no regard for the individual microbial species or the entire microbial community involved. Process design appears to be tackled empirically from a 'black box' approach; biological reactions or processes occurring within a system such as wastewater treatment are all lumped together and attributed to a single surrogate organism ie., the response of the surrogate to certain stimuli accounts for the total system response. This is similar to an analogy which Professor George Ekama (Dept of Civil Engineering, UCT), a leading scientist in wastewater treatment and process design, refers to where engineers, if, for example, are confronted with modelling the dynamics of carbon dioxide utilisation ofa forest, would recognise the accumulative system response and not give cognisance to each individual tree's contribution. It is true that if one had to consider every microbial species present in a highly organised community such as activated sludge, process models, designed to make quantitative and qualitative predictions as to the expected effluent quality from a particular design, would become increasingly complex and superfluous. It is evident from the countless accomplishments that engineers have succeeded, to a certain degree, in modelling wastewater treatment systems. One only has to consider the tremendous success of biological P (bio-P) removal and nitrification/denitrification processes at full-scale. However, there are limitations to this empirical approach and EBPR processes occasionally deteriorate in phosphate removal efficiency. In order to further optimise biological processes, whether they be organics oxidation, bio-P removal, nitrification or denitrification, biological community analyses will have to play a more significant role in design. The better microbial community structure and function is understood, the better the control and management of the system. With the advent of improved microbial identification and enumeration (to a certain extent) techniques (in situ), it was considered significant to investigate the mechanism ofbio-P removal and to elucidate which bacteria are actively responsible for this process. To this end, experimental work was conducted in two phases: \xAE laboratory, where samples of mixed liquor were obtained from a full-scale wastewater treatment facility exhibiting biological nutrient removal (BNR) characteristics and @ pilot plant, where an enhanced culture ofpolyphosphate accumulating organisms (PAO's) was developed and probed using molecular identification and enumeration techniques (as well as a cultivation-dependent approach). During phase \xAE of experimentat

Gouri Chakraborty, In‐Hyeok Park, R. Medishetty et al.

Chemical Reviews • 2021

Among the recent developments in metal-organic frameworks (MOFs), porous layered coordination polymers (CPs) have garnered attention due to their modular nature and tunable structures. These factors enable a number of properties and applications, including gas and guest sorption, storage and separation of gases and small molecules, catalysis, luminescence, sensing, magnetism, and energy storage and conversion. Among MOFs, two-dimensional (2D) compounds are also known as 2D CPs or 2D MOFs. Since the discovery of graphene in 2004, 2D materials have also been widely studied. Several 2D MOFs are suitable for exfoliation as ultrathin nanosheets similar to graphene and other 2D materials, making these layered structures useful and unique for various technological applications. Furthermore, these layered structures have fascinating topological networks and entanglements. This review provides an overview of different aspects of 2D MOF layered architectures such as topology, interpenetration, structural transformations, properties, and applications.

Rui Li, Tongtong Chen, Xiangliang Pan

ACS Nano • 2021

To address the serious threat of bacterial infection to public health, great efforts have been devoted to the development of antimicrobial agents for inhibiting bacterial growth, preventing biofilm formation, and sterilization. Very recently, metal-organic frameworks (MOFs) have emerged as promising materials for various antimicrobial applications owing to their different functions including the controlled/stimulated decomposition of components with bactericidal activity, strong interactions with bacterial membranes, and formation of photogenerated reactive oxygen species (ROS) as well as high loading and sustained releasing capacities for other antimicrobial materials. This review focuses on recent advances in the design, synthesis, and antimicrobial applications of MOF-based materials, which are classified by their roles as component-releasing (metal ions, ligands, or both), photocatalytic, and chelation antimicrobial agents as well as carriers or/and synergistic antimicrobial agents of other functional materials (antibiotics, enzymes, metals/metal oxides, carbon materials, etc.). The constituents, fundamental antimicrobial mechanisms, and evaluation of antimicrobial activities of these materials are highlighted to present the design principles of efficient MOF-based antimicrobial materials. The prospects and challenges in this research field are proposed.

Weibin Liang, Peter Wied, F. Carraro et al.

Chemical Reviews • 2021

Because of their efficiency, selectivity, and environmental sustainability, there are significant opportunities for enzymes in chemical synthesis and biotechnology. However, as the three-dimensional active structure of enzymes is predominantly maintained by weaker noncovalent interactions, thermal, pH, and chemical stressors can modify or eliminate activity. Metal-organic frameworks (MOFs), which are extended porous network materials assembled by a bottom-up building block approach from metal-based nodes and organic linkers, can be used to afford protection to enzymes. The self-assembled structures of MOFs can be used to encase an enzyme in a process called encapsulation when the MOF is synthesized in the presence of the biomolecule. Alternatively, enzymes can be infiltrated into mesoporous MOF structures or surface bound via covalent or noncovalent processes. Integration of MOF materials and enzymes in this way affords protection and allows the enzyme to maintain activity in challenge conditions (e.g., denaturing agents, elevated temperature, non-native pH, and organic solvents). In addition to forming simple enzyme/MOF biocomposites, other materials can be introduced to the composites to improve recovery or facilitate advanced applications in sensing and fuel cell technology. This review canvasses enzyme protection via encapsulation, pore infiltration, and surface adsorption and summarizes strategies to form multicomponent composites. Also, given that enzyme/MOF biocomposites straddle materials chemistry and enzymology, this review provides an assessment of the characterization methodologies used for MOF-immobilized enzymes and identifies some key parameters to facilitate development of the field.

Jian-Bin Lin, Tai T. T. Nguyen, R. Vaidhyanathan et al.

Science • 2021

Description A hydrophobic CO2 physisorbent Most materials for carbon dioxide (CO2) capture of fossil fuel combustion, such as amines, rely on strong chemisorption interactions that are highly selective but can incur a large energy penalty to release CO2. Lin et al. show that a zinc-based metal organic framework material can physisorb CO2 and incurs a lower regeneration penalty. Its binding site at the center of the pores precludes the formation of hydrogen-bonding networks between water molecules. This durable material can preferentially adsorb CO2 at 40% relative humidity and maintains its performance under flue gas conditions of 150°C. —PDS A metal-organic framework captures CO2 with high capacity and selectivity over steam with only a modest regeneration penalty. Metal-organic frameworks (MOFs) as solid sorbents for carbon dioxide (CO2) capture face the challenge of merging efficient capture with economical regeneration in a durable, scalable material. Zinc-based Calgary Framework 20 (CALF-20) physisorbs CO2 with high capacity but is also selective over water. Competitive separations on structured CALF-20 show not just preferential CO2 physisorption below 40% relative humidity but also suppression of water sorption by CO2, which was corroborated by computational modeling. CALF-20 has a low enthalpic regeneration penalty and shows durability to steam (>450,000 cycles) and wet acid gases. It can be prepared in one step, formed as composite materials, and its synthesis can be scaled to multikilogram batches.

Qi Wang, D. Astruc

Chemical Reviews • 2019

Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.

Jeongyong Lee, O. Farha, John M. Roberts et al.

Chemical Society Reviews • 2009

A critical review of the emerging field of MOF-based catalysis is presented. Discussed are examples of: (a) opportunistic catalysis with metal nodes, (b) designed catalysis with framework nodes, (c) catalysis by homogeneous catalysts incorporated as framework struts, (d) catalysis by MOF-encapsulated molecular species, (e) catalysis by metal-free organic struts or cavity modifiers, and (f) catalysis by MOF-encapsulated clusters (66 references).

Guorui Cai, P. Yan, Liangliang Zhang et al.

Chemical Reviews • 2021

Metal-organic frameworks (MOFs) have been widely recognized as one of the most fascinating classes of materials from science and engineering perspectives, benefiting from their high porosity and well-defined and tailored structures and components at the atomic level. Although their intrinsic micropores endow size-selective capability and high surface area, etc., the narrow pores limit their applications toward diffusion-control and large-size species involved processes. In recent years, the construction of hierarchically porous MOFs (HP-MOFs), MOF-based hierarchically porous composites, and MOF-based hierarchically porous derivatives has captured widespread interest to extend the applications of conventional MOF-based materials. In this Review, the recent advances in the design, synthesis, and functional applications of MOF-based hierarchically porous materials are summarized. Their structural characters toward various applications, including catalysis, gas storage and separation, air filtration, sewage treatment, sensing and energy storage, have been demonstrated with typical reports. The comparison of HP-MOFs with traditional porous materials (e.g., zeolite, porous silica, carbons, metal oxides, and polymers), subsisting challenges, as well as future directions in this research field, are also indicated.

Xinran Zhang, J. Maddock, T. Nenoff et al.

Chemical Society Reviews • 2022

Nuclear power will continue to provide energy for the foreseeable future, but it can pose significant challenges in terms of the disposal of waste and potential release of untreated radioactive substances. Iodine is a volatile product from uranium fission and is particularly problematic due to its solubility. Different isotopes of iodine present different issues for people and the environment. 129I has an extremely long half-life of 1.57 × 107 years and poses a long-term environmental risk due to bioaccumulation. In contrast, 131I has a shorter half-life of 8.02 days and poses a significant risk to human health. There is, therefore, an urgent need to develop secure, efficient and economic stores to capture and sequester ionic and neutral iodine residues. Metal–organic framework (MOF) materials are a new generation of solid sorbents that have wide potential applicability for gas adsorption and substrate binding, and recently there is emerging research on their use for the selective adsorptive removal of iodine. Herein, we review the state-of-the-art performance of MOFs for iodine adsorption and their host–guest chemistry. Various aspects are discussed, including establishing structure–property relationships between the functionality of the MOF host and iodine binding. The techniques and methodologies used for the characterisation of iodine adsorption and of iodine-loaded MOFs are also discussed together with strategies for designing new MOFs that show improved performance for iodine adsorption.