Long-term evaluation of soil-based bioelectrochemical green roof systems for greywater treatment.

Water scarcity has generated the need to identify new sources. Due to its low organic contaminant load, greywater reuse has emerged as a potential alternative. Moreover, the search for decentralized treatment systems in urban areas has prompted research on using green roofs for greywater treatment. However, the performance of organic matter removal is limited by the type of substrate and height of the growing media. Bioelectrochemical systems (BESs) improve treatment performance by providing an additional electron acceptor (the electrode). In this study, nine reactors under three different conditions, i.e., open circuit (OC), microbial fuel cell (MFC), and microbial electrolysis cell (MEC), were built to evaluate the treatment of synthetic greywater in a substrate-growing medium composed of perlite and coconut fiber and operated in batch-cycle mode for 397 days. The results suggested that using BESs enables greywater treatment and the removal of pollutants to levels that allow their reuse for irrigation. Furthermore, electrical conductivity was reduced from 732.4 ± 41.2 µS/cm2 in OC to 637.32 ± 22.73 µS/cm2 and 543.15 ± 19.69 µS/cm2 in MEC and MFC, respectively. The soluble chemical oxygen demand in the latter treatments reached 76% removal, compared to levels above the OC, which only reached approximately 67%. Microbial community analysis revealed differences, mainly in the cathodes, showing a higher development of Flavobacterium, Azospirillum, and Zoogloea in MFCs, which could explain the higher levels of organic matter removal in the other conditions, suggesting that the BES could produce an enrichment of beneficial bacterial groups for treatment. Therefore, implementing BESs in green roofs enables sustainable long-term greywater treatment.

Revealing the performance of aerotolerant anodes for electroactive nitrification/denitrification and current production under coexistence of oxygen and nitrate conditions.

The coexistence of oxygen and/or nitrate at anode usually affects the biofilm activities of traditional anaerobic anode, thereby deteriorating wastewater treatment performance of microbial fuel cells (MFCs). Improving the aerotolerant responses of anode biofilms is a challenge for field application. In this study, we report that using the electroactive nitrifying/denitrifying inoculum and air-cathode expansion could fabricate the aerotolerant anode biofilms (AAB) under affordable nitrate stress (90 ± 5 mg/L). The highest average removal efficiencies were 99% for chemical oxygen demand (COD), NH4+-N and total nitrogen. The highest average current output of 0.69 mA and power density of 290 mW/m2 were obtained. The average current was confirmed to be reduced 10%-78% but the power density remained almost stable except the quart-air-cathodes MFC by increasing dissolved oxygen concentration with expansion of the air-cathode area. The higher oxygen concentration also contributed to oxidation of ammonium through electroactive autotrophic nitrification. The facultative anaerobic bacteria including Thauera, Microsillaceae, Shinella, Blastocatellaceae, Rhodobacter, Comamonadaceae, Caldilineaceae were enriched, which forms the AAB to remove nitrogen and produce current. Therefore, an easy-to-use method to fabricate AAB is evaluated to realize practical applications of MFCs in wastewater treatment.

Boosting Electrochemical Performance via Extra-Role of La-Doped CeO2-δ Interlayer for "Oxygen Provider" at High-Current SOFC Operation.

Utilizing rare earth doped ceria in solid oxide cells (SOCs) engineering is indeed a strategy aimed at enhancing the electrochemical devices' durability and activity. Particularly, Gd-doped ceria (GDC) is actively used for barrier layer and catalytic additives in solid oxide fuel cells (SOFCs). In this study, experiments are conducted with La-doped CeO2 (LDC), in which the Ce sites are predominantly occupied by La, to prevent the formation of the Ce-Zr solid solution. This LDC is comparably used as a functional interlayer between the electrolyte and cathode if sintered at lower temperatures to avoid La2Zr2O7 impurity. In addition, the high substitution of La3+ into the ceria lattice improves the oxygen non-stoichiometry of LDC, leading to accelerated electrochemical high performance by the additional role of LDC for oxygen supplier capacitance at high current operation. Thus, it is confirmed that the improved SOFC high performance is achieved at the maximum power density (MPD) of ≈2.15 W cm-2 at 800 °C when the optimized LDC buffer layer is hired at the anode-supported typed-Samsung's SOFC by lowering the sintering temperature to prevent LDC's impurity reaction.

Studying the Effect of Operating Conditions and NO2 Cathode Contamination on PEM Fuel Cells Using Distribution Function of Relaxation Times Analysis.

The effect of NO2, an air pollutant, on the durability of polymer electrolyte membrane fuel cells (PEMFCs) and the affected electrochemical processes in the PEMFC following the contamination were investigated. In-situElectrochemical Impedance Spectroscopy (EIS) measurements were conducted on PEMFCs under different operating conditions of temperature and relative humidity (RH). NO2 was introduced to the cathode inlet flow. Analyses of the EIS measurements were performed using a genetic algorithm called ISGP (Impedance Spectroscopy by Genetic Programming) to obtain the distribution function of relaxation times (DFRT, a.k.a. DRT) models. Utilizing ISGP enabled us to differentiate the various phenomena in PEMFC and study how they are affected by NO2 contamination. Moreover, the experiments demonstrate the effectiveness of the mitigation method to flush the PEMFC and regenerate its performance after being contaminated, particularly at low operating temperatures. Energy-dispersive X-ray spectroscopy (EDS) technique is performed on the contaminated PEMFC to detect the presence of any nitrogen components in the FC's gas diffusion layer and the catalyst layer post the mitigation step. Cyclic Voltammetry is also performed on the contaminated cell to determine the effect of the contamination on the electrochemically active surface area of the cathode by evaluating the double-layer capacitance.

Proton Conduction via Water and Ammonia Coordinated Metal Cationic Species in MOF and MHOF Platforms.

Although metal-organic frameworks (MOFs) and metalo hydrogen-bonded organic frameworks (MHOFs) are designed as promising solid-state proton conductors by incorporating various protonic species intrinsically or extrinsically, design and development of such materials by employing the concept of proton conduction through coordinated polar protic solvent is largely unexplored. Herein, we have constructed two proton-conducting materials having different solvent coordinated metal cationic species: In-H2O-MOF, ({[In(H2O)6][In3(Pzdc)6]·15H2O}n; H2Pzdc: pyrazine-2,3-dicarboxylic acid) with coordinated water molecules from hexaaquaindium cationic species, and MHOF-4, ([{Co(NH3)6}2(2,6-NDS)2(H2O)2]n; 2,6-H2NDS: 2,6-naphthalenedisulfonic acid) with coordinated ammonia from hexaammoniacobalt cationic species. Interestingly, higher proton conductivity was achieved for In-H2O-MOF (1.5 × 10-5 S cm-1) than MHOF-4 (6.3 × 10-6 S cm-1) under the extreme conditions (80 ºC and 95% RH), which could be attributed to enhanced acidity of coordinated water molecules having much lower pKa value than that of coordinated ammonia. Greater charge polarization on hydrogen atoms of In3+-coordinated water molecules than that of Co2+-coordinated ammonia led to the high conductivity of In-H2O-MOF, as evident by quantum chemical studies. Such a comparative study on metal-coordinated protic polar solvents in achieving proton conduction in crystalline solids is yet to be made.

Green Hydrogen Production by Low-Temperature Membrane-Engineered Water Electrolyzers, and Regenerative Fuel Cells.

Green hydrogen (H2) is an essential component of global plans to reduce carbon emissions from hard-to-abate industries and heavy transport. However, challenges remain in the highly efficient H2 production from water electrolysis powered by renewable energies. The sluggish oxygen evolution restrains the H2 production from water splitting. Rational electrocatalyst designs for highly efficient H2 production and oxygen evolution are pivotal for water electrolysis. With the development of high-performance electrolyzers, the scale-up of H2 production to an industrial-level related activity can be achieved. This review summarizes recent advances in water electrolysis such as the proton exchange membrane water electrolyzer (PEMWE) and anion exchange membrane water electrolyzer (AEMWE). The critical challenges for PEMWE and AEMWE are the high cost of noble-metal catalysts and their durability, respectively. This review highlights the anode and cathode designs for improving the catalytic performance of electrocatalysts, the electrolyte and membrane engineering for membrane electrode assembly (MEA) optimizations, and stack systems for the most promising electrolyzers in water electrolysis. Besides, the advantages of integrating water electrolyzers, fuel cells (FC), and regenerative fuel cells (RFC) into the hydrogen ecosystem are introduced. Finally, the perspective of electrolyzer designs with superior performance is presented.

Electrocatalytic ethanol oxidation reaction: recent progress, challenges, and future prospects.

Direct ethanol fuel cells (DEFCs) have been widely considered as a feasible power conversion technology for portable and mobile applications. The economic feasibility of DEFCs relies on two conditions: a notable reduction in the expensive nature of precious metal electrocatalysts and a simultaneous remarkable improvement in the anode's long-term performance. Despite the considerable progress achieved in recent decades in Pt nanoengineering to reduce its loading in catalyst ink with enhanced mass activity, attempts to tackle these problems have yet to be successful. During the ethanol oxidation reaction (EOR) at the anode surface, Pt electrocatalysts lose their electrocatalytic activity rapidly due to poisoning by surface-adsorbed reaction intermediates like CO. This phenomenon leads to a significant loss in electrocatalytic performance within a relatively short time. This review provides an overview of the mechanistic approaches during the EOR of noble metal-based anode materials. Additionally, we emphasized the significance of many essential factors that govern the EOR activity of the electrode surface. Furthermore, we provided a comprehensive examination of the challenges and potential advancements in electrocatalytic EOR.

Parameter characterization of PEM fuel cell mathematical models using an orthogonal learning-based GOOSE algorithm.

In this paper, a new method is designed to effectively determine the parameters of proton exchange membrane fuel cells (PEMFCs), i.e., ξ 1 , ξ 2 , ξ 3 , ξ 4 , R C , λ , and b . The fuel cells (FCs) involve multiple variable quantities with complex non-linear behaviours, demanding accurate modelling to ensure optimal operation. An accurate model of these FCs is essential to evaluate their performance accurately. Furthermore, the design of the FCs significantly impacts simulation studies, which are crucial for various technological applications. This study proposed an improved parameter estimation procedure for PEMFCs by using the GOOSE algorithm, which was inspired by the adaptive behaviours found in geese during their relaxing and foraging times. The orthogonal learning mechanism improves the performance of the original GOOSE algorithm. This FC model uses the root mean squared error as the objective function for optimizing the unknown parameters. In order to validate the proposed algorithm, a number of experiments using various datasets were conducted and compared the outcomes with different state-of-the-art algorithms. The outcomes indicate that the proposed GOOSE algorithm not only produced promising results but also exhibited superior performance in comparison to other similar algorithms. This approach demonstrates the ability of the GOOSE algorithm to simulate complex systems and enhances the robustness and adaptability of the simulation tool by integrating essential behaviours into the computational framework. The proposed strategy facilitates the development of more accurate and effective advancements in the utilization of FCs.

A High-Methanol-Permeation Resistivity Polyamide-Based Proton Exchange Membrane Fabricated via a Hyperbranching Design.

Four non-fluorinated sulfonimide polyamides (s-PAs) were successfully synthesized and a series of membranes were prepared by blending s-PA with polyvinylidene fluoride (PVDF) to achieve high-methanol-permeation resistivity for direct methanol fuel cell (DMFC) applications. Four membranes were fabricated by blending 50 wt% PVDF with s-PA, named BPD-101, BPD-102, BPD-111 and BPD-211, respectively. The s-PA/PVDF membranes exhibit high methanol resistivity, especially for the BPD-111 membrane with methanol resistivity of 8.13 × 10-7 cm2/s, which is one order of magnitude smaller than that of the Nafion 117 membrane. The tensile strength of the BPD-111 membrane is 15 MPa, comparable to that of the Nafion 117 membrane. Moreover, the four membranes also show good thermal stability up to 230 °C. The BPD-x membrane exhibits good oxidative stability, and the measured residual weights of the BPD-111 membrane are 97% and 93% after treating in Fenton's reagent (80 °C) for 1 h and 24 h, respectively. By considering the mechanical, thermal and dimensional properties, the polyamide proton-exchange membrane exhibits promising application potential for direct methanol fuel cells.

Semimetal-triggered covalent interaction in Pt-based intermetallics for fuel-cell electrocatalysis.

Platinum-based intermetallic compounds (IMCs) play a vital role as electrocatalysts in a range of energy and environmental technologies, such as proton exchange membrane fuel cells. However, the synthesis of IMCs necessitates recombination of ordered Pt-M metallic bonds with high temperature driving, which is generally accompanied by side effects for catalysts' structure and performance. In this work, we highlight that semimetal atoms can trigger covalent interactions to break the synthesis-temperature limitation of platinum-based intermetallic compounds and benefit fuel-cell electrocatalysis. Attributed to partial fillings of p-block in semimetal elements, the strong covalent interaction of d-p π backbonding can benefit the recombination of ordered Pt-M metallic bonds (PtGe, PtSb and PtTe) in the synthesis process. Moreover, this covalent interaction in metallic states can further promote both electron transport and orbital fillings of active sites in fuel cells. The semimetal-Pt IMCs were obtained with a temperature 300 K lower than that needed for the synthesis of metal-Pt intermetallic compounds and reached the highest CO-tolerant oxygen reduction activity (0.794 A mg-1 at 0.9 V and 5.1% decay under CO poisoning) among reported electrocatalysts. We anticipate that semimetal-Pt IMCs will offer new insights for the rational design of advanced electrocatalysts for fuel cells.

A hybrid FeOx/CoOx/Pt ternary nanocatalyst for augmented catalysis of formic acid electro-oxidation.

Platinum-based catalysts that have long been used as the anodes for the formic acid electro-oxidation (FAO) in the direct formic acid fuel cells (DFAFCs) were susceptible to retrogradation in performance due to CO poisoning that impaired the technology transfer in industry. This work is designed to overcome this challenge by amending the Pt surface sequentially with nanosized cobalt (nano-CoOx, fibril texture of ca. 200 nm in particle size) and iron (nano-FeOx, nanorods of particle size and length of 80 and 253 nm, respectively) oxides. This enriched the Pt surface with oxygenated groups that boosted FAO and mitigated the CO poisoning. The unfilled d-orbitals of the transition metals and their tendency to vary their oxidations states presumed their participation in a faster mechanism of FAO. Engineering the Pt surface in this FeOx/CoOx/Pt hierarchy resulted in a remarkable activity toward FAO, that exceeded four times that of the Pt catalyst with up to ca. 2.5 times improvement in the catalytic tolerance against CO poisoning. This associated a ca. - 32 mV shift in the onset potential of FAO which increased to - 40 mV with a post-activation of the same catalyst at - 0.5  in 0.2 mol L-1 NaOH, displaying the catalyst's competitiveness in reducing overpotentials in DFAFCs. It also exhibited a favorable amelioration in the catalytic durability in long-termed chronoamperometric electrolysis. The electrochemical impedance spectroscopy and the CO stripping voltammetry were employed to elucidate the origin of enhancement.

Synergistic Molecular Alignment and Dipole Polarization in Stretched Nafion/Poly(vinylidene fluoride) Blend Membranes for High Proton Conduction in PEMFCs.

The nanostructure of Nafion and poly(vinylidene fluoride) (PVDF) blend membranes is successfully aligned through a mechanical uniaxial stretching method. The phase-separated morphology of Nafion molecules distinctly forms hydrophilic proton channels with increased connectivity, resulting in enhanced proton conductivity. Additionally, the crystalline phase of PVDF molecules undergoes a successful transformation from the α- to ß-phase during membrane stretching, demonstrating an alignment of fluorine and hydrogen atoms with a TTTT(trans) structure. The aligned nanostructure of the blend film, combined with the dipole polarization of the ß-phase PVDF, synergistically enhances the proton conduction through the membrane for operating proton-exchange membrane fuel cells (PEMFCs). The controlled structures of the blend membranes are thoroughly investigated using atomic force microscopy and small-angle X-ray scattering. Furthermore, the improved in-plane proton conductivity facilitates increased proton conduction at the interface between the membrane and catalyst layer in the membrane-electrode assembly, ultimately enhancing the power generation of PEMFCs.

Enhancement of Mass Transport in Catalyst Layers of HT-PEMFC with Tetrafluorophenyl Phosphonic Acid Binder.

The design and development of new and efficient catalyst binder materials are important for improving cell performance in high-temperature proton-exchange membrane fuel cells (HT-PEMFCs). In this study, a series of tetrafluorophenyl phosphonic acid-based binder materials (PF-y-P, y = 1, 0.83, and 0.67) with rigid structures and controllable degrees of phosphonation were prepared and used in HT-PEMFCs using the ultra-strong acid-catalyzed Friedel-Crafts reaction and the combined Michaelis-Arbuzov reaction. The samples exhibited high stability, low water uptake, superior proton conductivity, and cell performance. In addition, the oxygen mass transport properties of the PF-1-P binder were investigated using high-temperature microelectrode electrochemical testing techniques. Compared with the phosphoric acid-doped polybenzimidazole (PBI) binder, the O2 solubility of PF-1-P binder material increased by 30% (5.36 × 10-6 mol cm-3) and the PF-1-P binder material exhibited better cell stability in HT-PEMFCs. After 10.5 h of discharge at a constant current of 0.12 A cm-2, the MEA voltage decreased by 7.1% and 20.8% in case of the PF-1-P and PBI binders, respectively.

Preparation of cathode catalysts for efficient direct lignin fuel cells by nitrogen doping reduction of oxidized graphene with phthalocyanine iron and Kraft lignin.

Direct lignin fuel cells (DLFC) are one of the important forms of high value-added utilization of lignin. In this study, lignin was studied not only as a fuel but also as a catalyst. Specifically, Kraft lignin was modified with ZnCl2, KOH and THF (Tetrahydrofuran) respectively, and added to the catalyst after activation. The results of scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), Brunauer - Emmett - Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectra shown that AL/FePc-NrGO (activated lignin/iron phthalocyanine/nitrogen-doped reduction of graphene oxide) three-dimensional composite catalyst has been synthesized. The results showed that KOH-activated Kraft lignin had the best performance as an oxygen reduction reaction (ORR) catalyst, with a half-wave potential (E1/2) of 0.73 V and a limiting diffusion current density of 4.3 mA cm-1. The THF-modified catalyst showed similar stability and methanol resistance to 20 % Pt/C at ORR. The ORR catalyst applied to the DLFC has the best electrical performance with an open circuit voltage (OCV) was 0.53 V and the maximum power density it could reach 95.29 mW m-2 when the catalyst was modified with THF. It is encouraging that the AL/FePc-NrGO catalyst has better-generated electricity performance than 20 % Pt/C. This work has provided a new idea for developing non-noble metal catalysts and studying direct biomass liquid fuel cells.

Unveiling Direct Electrochemical Oxidation of Methane at the Ceria/Gas Interface.

Solid oxide fuel cells (SOFCs) stand out in sustainable energy systems for their unique ability to efficiently utilize hydrocarbon fuels, particularly those from carbon-neutral sources. CeO2-δ (ceria) based oxides embedded in SOFCs are recognized for their critical role in managing hydrocarbon activation and carbon coking. However, even for the simplest hydrocarbon molecule, CH4, the mechanism of electrochemical oxidation at the ceria/gas interface is not well understood and the capability of ceria to electrochemically oxidize methane remains a topic of debate. This lack of clarity stems from the intricate design of standard metal/oxide composite electrodes and the complex nature of electrode reactions involving multiple chemical and electrochemical steps. This study presents a Sm-doped ceria thin-film model cell that selectively monitors CH4 direct-electro-oxidation on the ceria surface. Using impedance spectroscopy, operando X-ray photoelectron spectroscopy, and density functional theory, it is unveiled that ceria surfaces facilitate C─H bond cleavage and that H2O formation is key in determining the overall reaction rate at the electrode. These insights effectively address the longstanding debate regarding the direct utilization of CH4 in SOFCs. Moreover, these findings pave the way for an optimized electrode design strategy, essential for developing high-performance, environmentally sustainable fuel cells.

Sulfonamide-Sulfonimide Copolymers as Novel, Fluorine-Lean Type of Proton Exchange Membranes for Fuel Cell Application.

In this work, a novel type of fluorine-lean proton exchange membranes is presented, using sulfonamide-sulfonimide functional groups for ion conduction. These groups are constructed on a polystyrene backbone for simple and cost-efficient usage as well as rapid scalability. The polymer is further tailored by adjusting the sulfonamide functionality with various end-groups, namely pentafluorophenyl, 4-fluorophenyl, butyl and octyl groups. These groups affect the pKa, leading to pKa values of 5.7 for the pentafluorophenyl substitution and pKa 10.5 for the alkyl chain. The glass transition temperature of the sulfonamide homopolymers can be reduced from Tg = 151°C (Pentafluorophenyl) to 49°C (Octyl), making the ionomer more flexible at room temperature. The combination of the non-swelling sulfonamide further mitigates the high water uptake of the sulfonimide while maintaining the nominal ion exchange capacity. This combination leads to extremely high proton conductivities with up to σ = 283 mS cm-1 at room temperature, which is clearly outperforming Nafion and approaches values for acid doped systems. This approach can pave the way to a novel type of ion conducting class in proton exchange membrane fuel cells.

Calcined pyrite accelerates sulfur metabolic and electron transfer in driving targeted microbial fuel cell denitrification.

The sulfur powder as electron donor in driving dual-chamber microbial fuel cell denitrification (S) process has the advantages in economy and pollution-free to treat nitrate-contained groundwater. However, the low efficiency of electron utilization in sulfur oxidation (ACE) is the bottleneck to this method. In this study, the addition of calcined pyrite to the S system (SCP) accelerated electron generation and intra/extracellular transfer efficiency, thereby improving ACE and denitrification performance. The highest nitrate removal rate reached to 3.55 ± 0.01 mg N/L/h in SCP system, and the ACE was 103 % higher than that in S system. More importantly, calcined pyrite enhanced the enrichment of functional bacteria (Burkholderiales, Thiomonas and Sulfurovum) and functional genes which related to sulfur metabolism and electron transfer. This study was more effective in removing nitrate from groundwater without compromising the water quality.

Defying Gravity to Enhance Power Output and Conversion Efficiency in a Vertically Oriented Four-Electrode Microfluidic Microbial Fuel Cell.

High power output and high conversion efficiency are crucial parameters for microbial fuel cells (MFCs). In our previous work, we worked with microfluidic MFCs to study fundamentals related to the power density of the MFCs, but nutrient consumption was limited to one side of the microchannel (the electrode layer) due to diffusion limitations. In this work, long-term experiments were conducted on a new four-electrode microfluidic MFC design, which grew Geobacter sulfurreducens biofilms on upward- and downward-facing electrodes in the microchannel. To our knowledge, this is the first study comparing electroactive biofilm (EAB) growth experiencing the influence of opposing gravitational fields. It was discovered that inoculation and growth of the EAB did not proceed as fast at the downward-facing anode, which we hypothesize to be due to gravity effects that negatively impacted bacterial settling on that surface. Rotating the device during the growth phase resulted in uniform and strong outputs from both sides, yielding individual power densities of 4.03 and 4.13 W m-2, which increased to nearly double when the top- and bottom-side electrodes were operated in parallel as a single four-electrode MFC. Similarly, acetate consumption could be doubled with the four electrodes operated in parallel.

Assessing the impact of soil microbial fuel cells on atrazine removal in soil.

Widespread pesticide use in agriculture is a major source of soil pollution, driving biodiversity loss and posing serious threads to human health. The recalcitrant nature of most of these pesticides demands for effective remediation strategies. In this study, we assess the ability of soil microbial fuel cell (SMFC) technology to bioremediate soil polluted by the model pesticide atrazine. To elucidate the degradation mechanism and consequently define effective implementation strategies, we provide the first comprehensive investigation of the SMFC performance, in which the monitoring of the electrochemical performance of the system is combined with Quadrupole Time-of-Flight (QTOF) mass spectrometry and microbial analyses. Our results show that, while both SMFC and natural attenuation lead to a reduction on atrazine levels, the SMFC modulates the activity of different microbial pathways. As a result, atrazine degradation by natural attenuation leads to high levels of deisoproylatrazine (DIPA), a very toxic degradation metabolite, while DIPA levels in soil treated by SMFC remain comparatively low. The beta diversity and differential abundance analyses revealed how the microbial community evolves over time in the SMFCs degrading atrazine, demonstrating the enrichment of electroactive taxa on the anode, and the enrichment of a mixture of electroactive and atrazine-degrading taxa at the cathode. The detection and taxonomic classification of peripheral atrazine degrading genes, atzA, atzB and atzC, was carried out in combination with the differential abundance analysis. Results revealed that these genes are likely harboured by members of the order Rhizobiales enriched at the cathode, thus promoting atrazine degradation via the conversion of hydroxyatrazine (HA) into N-isopropylammelide (NIPA), as confirmed by mass spectrometry data. Overall, the comprehensive approach adopted in this work, provides fundamental insights into the degradation pathways of atrazine in soil by SMFC technology, which is critical for practical applications, thus suggesting an effective approach to advance research in the field.

Biohydrogen upgradation and wastewater treatment in 3-chambered bioelectrochemical system assisted with H2/O2-based redox reactions.

The current need for the upgradation of biohydrogen generation and contaminant removal in two-chambered microbial electrolysis cells (MECs) compels the design of alternatives i.e. bioelectrochemical systems (BESs) to conventional reactors. In this study, a novel three-chambered design of MEC (BES-1) was developed with a common anodic chamber and a two-cathodic chambers at both ends of the anodic chamber, separated by a membrane (MEC-MEC). To facilitate electricity recovery, a microbial fuel cell (MFC) was integrated with an MEC in BES-2. Cathodic hydrogen recovery of 8.89 and 4.81 mL/L.day, and organic matter removal of 82% and 76% were obtained in BES-1 and BES-2, respectively, demonstrating their capabilities for bioremediation. Electrochemical analyses also revealed that cathodic reduction reactions improved with the effective utilization of protons during integration. Our design regulates H2/O2-associated electrochemical reactions and is beneficial for maintaining pH equilibrium. From cost and energy perspectives, the integrated BES provides a platform for two different reactions simultaneously and is capable of boosting overall hydrogen recovery and organic matter removal. Moreover, the compactness and competitiveness of such an integrated BES increase its scope for real-world applications.