• 2021

• 2018

• 2017

• 2017

• 2011

• 2012

• 2017

• 2021

• 2019

• 2013

• 2015

An additional low concentration chamber using two adjacent anion exchange membranes filled 50% with resin reduced nitrogen crossover to the anode.

• 2023

• 2017

• 2024

• 2014

• 2011

A new type of bioelectrochemical system for producing electrical power, called a microbial reverse-electrodialysis cell (MRC), was developed to increase voltages and power densities compared to those generated individually by microbial fuel cells (MFCs) or reverse electrodialysis (RED) systems. In RED systems, electrode overpotentials create significant energy losses due to thermodynamically unfavorable electrode reactions, and therefore a large number of stacked cells must be used to have significant energy recovery. This results in high capital costs for the large number of membranes, and increases energy losses from pumping water through a large number of cells. In an MRC, high overpotentials are avoided through oxidation of organic matter by exoelectrogenic bacteria on the anode and oxygen reduction on the cathode. An MRC containing only five pairs of RED cells, fed solutions typical of seawater (600 mM NaCl) and river water (12 mM NaCl) at 0.85 mL/min, produced up to 3.6 W/m(2) (cathode surface area) and 1.2-1.3 V with acetate as a substrate. Pumping accounted for <2% of the produced power. A higher flow rate (1.55 mL/min) increased power densities up to 4.3 W/m(2). COD removal was 98% with a Coulombic efficiency of 64%. Power production by the individual components was substantially lower with 0.7 W/m(2) without salinity driven energy, and <0.015 W/m(2) with reduced exoelectrogenic activity due to substrate depletion. These results show that the combination of an MFC and a RED stack synergistically increases performance relative to the individual systems, producing a new type of system that can be used to more efficiently capture salinity driven energy from seawater and river water.

• 2019

• 2017

This thesis aims to explain the metal recovery through the study of their components using Copper as a model compound of the heavy metals. Different electrochemical cells distribution and sizes were used to improve efficiency and current density. Two different electron donors were tested, acetate as a model compound from the organic matter fermentation and hydrogen as a model compound of inorganic electron donor used in industry. Chapter 1 of the thesis is an introduction to the topic. Chapter 2 shows how a reduction in internal resistance results in a step forward in the power production and current density of an MFC that couples acetate oxidation to copper reduction with an anion exchange membrane. This chapter also identifies limitations of the technology. One of these constraints is the availability of organic electron donor. In remote areas, the technology can be attractive in places where organic electron donors are available. In many places that have metal-containing waste streams, however, no such organic electron donors are available. Therefore, Chapter 3 investigated hydrogen as an electron donor for copper recovery. Hydrogen is available as a waste stream in the metal production industry. We show that hydrogen can be oxidized biologically at a bio-anode, and can be combined with copper recovery while producing electricity. One of the limitations that limited power production was a mass transfer of hydrogen from the gas phase to the biofilm. In Chapter 4, we studied the use of a gas diffusion electrode to improve mass transfer of hydrogen at a bio-anode. Chapter 5 focuses on an up-scaled design of the MFC for copper recovery using as a model the electroplating baths from metallurgy industry. Because considerable energy losses occur in a bipolar membrane, we investigated if carbon dioxide could be used as a charge carrier, resulting in lower energy losses. In Chapter 6, the improvements are discussed with relation to existing technologies, and an outlook for practical application is given.

• 2009

• 2007

Preface. 1. Introduction. 1.1. Energy needs. 1.2. Energy and the challenge of global climate change. 1.3. Bioelectricity generation using a microbial fuel cell --the process of electrogenesis. 1.4. MFCs and energy sustainability of the water infrastructure. 1.5. MFC technologies for wastewater treatment. 1.6. Renewable energy generation using MFCs. 1.7. Other applications of MFC technologies. 2. Exoelectrogens. 2.1. Introduction. 2.2. Mechanisms of electron transfer. 2.3. MFC studies using known exoelectrogenic strains. 2.4. Community analysis. 2.5. MFCs as tools for studying exoelectrogens. 3. Voltage generation. 3.1. Voltage and current. 3.2. Maximum voltages based on thermodynamic relationships. 3.3. Anode potentials and enzyme potentials. 3.4. Role of enzymes versus communities in setting anode potentials. 3.5. Voltage generation by fermentative bacteria? 4. Power generation. 4.1. Calculating power. 4.2. Coulombic and energy efficiency. 4.3. Polarization and power density curves. 4.4. Measuring internal resistance. 4.5. Chemical and electrochemical analysis of reactors. 5. Materials. 5.1. Finding low-cost, highly efficient materials. 5.2. Anode materials. 5.3. Membranes and separators (and chemical transport through them). 5.4. Cathode materials. 5.5. Long term stability of different materials. 6. Architecture. 6.1. General requirements. 6.2. Air-cathode MFCs. 6.3. Aqueous cathodes using dissolved oxygen. 6.4. Two chamber reactors with soluble catholytes or poised potentials. 6.5. Tubular packed bed reactors. 6.6. Stacked MFCs. 6.7. Metal catholytes. 6.8. Biohydrogen MFCs. 6.9. Towards a scaleable MFC architecture. 7. Kinetics and Mass transfer. 7.1. Kinetic or mass transfer models? 7.2. Boundaries on rate constants and bacterial characteristics. 7.3. Maximum power from a monolayer of bacteria. 7.4. Maximum rate of mass transfer to a biofilm. 7.5. Mass transfer per reactor volume. 8. MECs for hydrogen production. 8.1. Principle of operation. 8.2. MEC systems. 8.3. Hydrogen yields. 8.4. Hydrogen recovery. 8.5. Energy recovery. 8.6. Hydrogen losses. 8.7. Differences between the MEC and MFC systems. 9. MFCs for Wastewater Treatment. 9.1. Process trains for WWTPs. 9.2. Replacement of the biological treatment reactor with an MFC. 9.3. Energy balances for WWTPs. 9.4. Implications for reduced sludge generation. 9.5. Nutrient removal. 9.6. Electrogenesis versus methanogensis. 10. Other MFC Technologies. 10.1. Different applications for MFC-based technologies. 10.2. Sediment MFCs. 10.3. Enhanced sediment MFCs. 10.4. Bioremediation using MFC technologies. 11. Fun! 11.1 MFCs for new scientists and inventors. 11.2 Choosing your inoculum and media. 11.3 MFC materials: electrodes and membranes. 11.4 MFC architectures that are easy to build. 11.5 MFC reactors 11.6 Operation and assessment of MFCs. 12. Outlook. 12.1 MFCs yesterday and today. 12.2 Challenges for bringing MFCs to commercialization. 12.3 Accomplishments and outlook. Notation. References. Index.

• 2011

• 2020

The proof-of-principle of metal recovery by using the microbial electrochemical snorkel (MES) is provided for the first time. Copper electrodes were short-circuited with the bioanodes of sediment microbial fuel cells (MFC). Two MES setups with and without separation of the compartments by proton exchange membrane (PEM) were developed and their performance was compared with that of an MFC loaded by 510 Ω external resistance. A copper removal of 97.8 ± 4.5% and 98.3 ± 4.8% was achieved for 10 days by MES with PEM and MFC, respectively, while by using MES without PEM a removal of over 95% was obtained for only 2 days. In both operation modes, Cu2O coatings were deposited on the cathodes. The highest cathodic efficiency of 61.7 ± 6.9% was achieved with the MES without PEM, while the highest copper recovery of 42.4 ± 4.9% was obtained with the MES with PEM. The regeneration of copper reached by using MES is over 10% higher than that gained by the MFC. The obtained results show the applicability of MES for water purification from copper without additional energy input.

• 2022

In this study, we demonstrate for the first time the use of the microbial electrochemical snorkel (MES) for silver recovery from aqueous solutions. For comparison, identical bioelectrochemical reactors in which the cathodes were connected through a 510 Ω load resistor (MFC) with the bio-anodes of well-acclimated sediment microbial fuel cells were operated at the same other conditions. Three different types of cathodes - silver foil, copper foil, and graphitized paper, were explored for silver recovery from AgNO3 solution. The data obtained show that the operation in MES mode is more advantageous than that in MFC mode in terms of both silver removal and recovery. The XPS analysis has proved that on the silver foil and graphitized paper cathodes the silver is recovered as Ag0 particles, while on the copper foil cathodes mixed Ag-Cu deposits are obtained due to the predominant electroless displacement of Cu by Ag+. The superiority of operation in MES mode was also confirmed by experiments performed with [Ag(S2O3)2]3- - containing solution, simulating exhausted photographic fixer. The total amount of silver was removed from the MES-catholyte for 24 hours, while during the operation in MFC mode a silver removal of 88.2±5.8 % was reached.

• 2025

• 2010

• 2024

• 2013

• 2023

• 2023

• 2022

• 2020

• 2019

• 2012

Microbial desalination cells (MDCs) use the electrical current generated by microbes to simultaneously treat wastewater, desalinate water, and produce bioenergy. However, current MDC systems transfer salts to the treated wastewater and affect wastewater's beneficial use. A microbial capacitive desalination cell (MCDC) was developed to address the salt migration and pH fluctuation problems facing current MDCs and improve the efficiency of capacitive deionization. The anode and cathode chambers of the MCDC were separated from the middle desalination chamber by two specially designed membrane assemblies, which consisted of cation exchange membranes and layers of activated carbon cloth (ACC). Taking advantage of the potential generated across the microbial anode and the air-cathode, the MCDC was capable of removing 72.7 mg total dissolved solids (TDS) per gram of ACC without using any external energy. The MCDC desalination efficiency was 7 to 25 times higher than traditional capacitive deionization processes. Compared to MDC systems, where the volume of concentrate can be substantial, all of the removed ions in the MCDC were adsorbed in the ACC assembly double layer capacitors without migrating to the anolyte or catholyte, and the electrically adsorbed ions could be recovered during assembly regeneration. The two cation exchange membrane based assemblies allowed the free transfer of protons across the system and thus prevented significant pH changes observed in traditional MDCs.

• 2012

• 1995

• 2015

A mediator-type bioelectrochemical sensor was developed by using polypyrrole (PPy) immobilized ferricyanide (FC) as mediator and immobilized Pseudomonas aeruginosa (P. aeruginosa) as a biosensing film for biochemical oxygen demand (BOD) fast detection. The sensor chip consists of a three-electrode system, with Au working electrode (WE), Pt counter electrode (CE) and Pt pseudoreference electrode (RE) compactly integrated as a disposable using micro-electro-mechanism system (MEMS) technology. The FC mediator and P. Aeruginosa microorganisms have been embedded in PPy matrix on gold microelectrode surface during the electropolymerization of pyrrole monomer using electrochemical cyclic voltammetry (CV) method. This bioelectrochemical sensor responds to BOD due to yielded ferrocyanide during catalytic reduction by metabolic reactions of microorganisms. A good linear correlation with chemically determined BOD values was obtained from 5 to 100 mg/L with fast response time. The proposed sensor in this paper is significant for BOD fast detection.

• 1995

• 0

• 0

• 0