Ion exchange membrane optimized light-driven photoelectrochemical unit for efficiency simultaneous organic degradation and metal recovery from the mine wastewater

Hydroxyl radical mediated extracellular degradation of tetracycline under aerobic and anaerobic conditions stimulated by bio-FeS nanoparticles

The extracellular degradation of antibiotics facilitated by bio-nanoparticles is significant in the field of waste valorization. Among different bio-nanoparticles, bio-FeS nanoparticles stand out for their convenient and cost-effective synthesis. Nevertheless, there is a lack of understanding regarding the extracellular degradation of pollutants driven by bio-FeS nanoparticles. Hence, this study aimed to investigate the role of bio-FeS nanoparticles in the extracellular degradation of tetracycline under aerobic and anaerobic conditions. The findings demonstrated that bio-FeS nanoparticles generated hydroxyl radical (·OH), which significantly contributes to the degradation of tetracycline in both aerobic and anaerobic environments. The production of ·OH in anaerobic conditions was primarily attributed to the limited formation of FeS2 during the biosynthesis of nanoparticles, which was very different from aerobic conditions. The bio-FeS nanoparticles facilitated extracellular electron transport by promoting electron shuttles and Fe(II)/Fe(III) cycling, resulting in the continuous production of ·OH. The degradation pathways showed differences under aerobic and anaerobic conditions, with intermediates exhibiting higher toxicity and greater cellular damage under aerobic conditions. However, in anaerobic conditions, bio-FeS nanoparticles enabled the successful integration of intracellular and extracellular degradation of tetracycline. This research proposed a new avenue for biocatalysis and environmental remediation.

Toward Functionality and Deactivation of Metal-Single-Atom in Heterogeneous Photocatalysts

Single-atom heterogeneous catalysts (SAHCs) provide an enticing platform for understanding catalyst structure-property-performance relationships. The 100% atom utilization and adjustable local coordination configurations make it easy to probe reaction mechanisms at the atomic level. However, the progressive deactivation of metal-single-atom (MSA) with high surface energy leads to frequent limitations on their commercial viability. This review focuses on the atomistic-sensitive reactivity and atomistic-progressive deactivation of MSA to provide a unifying framework for specific functionality and potential deactivation drivers of MSA, thereby bridging function, purpose-modification structure-performance insights with the atomistic-progressive deactivation for sustainable structure-property-performance accessibility. The dominant functionalization of atomically precise MSA acting on properties and reactivity encompassing precise photocatalytic reactions is first systematically explored. Afterward, a detailed analysis of various deactivation modes of MSA and strategies to enhance their durability is presented, providing valuable insights into the design of SAHCs with deactivation-resistant stability. Finally, the remaining challenges and future perspectives of SAHCs toward industrialization, anticipating shedding some light on the next stage of atom-economic chemical/energy transformations are presented.

High-performance nanofiltration concentrate treatment by a five-chamber bioelectrochemical system

A combination of bioelectrochemical systems and electrodialysis has been considered an effective strategy for removing salts from the nanofiltration (NF) concentrate of electroplating wastewater; however, the recovery efficiency of multivalent metals is low. Herein, a new process based on microbial electrolysis desalination and chemical-production cell with five chambers (MEDCC-FC) has been proposed for the simultaneous desalination and recovery of the multivalent metals from NF concentrate. The MEDCC-FC was found to be significantly superior to the MEDCC with the monovalent selective cation exchange membrane (MEDCC-MSCEM) and MEDCC with the cation exchange membrane (MEDCC-CEM), in terms of the elevated desalination efficiency, multivalent metal recovery efficiency, current density, and coulombic efficiency, and decreased energy consumption and membrane fouling. Within 12 h, the MEDCC-FC provided the desirable outcome, indicated by a maximum current density of 6.88 ± 0.06 A/m2, desalination efficiency of 88 ± 10%, metals recovery efficiency of >58%, and total energy consumption of 1.17 ± 0.11 kWh for the per kg total dissolved solids removal. Mechanistic studies revealed that the integration of CEM and MSCEM in the MEDCC-FC promoted the separation and recovery of multivalent metal. These findings revealed that the proposed MEDCC-FC was promising in treating NF concentrate of electroplating wastewater towards advantages of effectiveness, economic viability, and flexibility.

Recent Progress in Interface Engineering of Nanostructures for Photoelectrochemical Energy Harvesting Applications

With rapid and continuous consumption of nonrenewable energy, solar energy can be utilized to meet the energy requirement and mitigate environmental issues in the future. To attain a sustainable society with an energy mix predominately dependent on solar energy, photoelectrochemical (PEC) device, in which semiconductor nanostructure-based photocatalysts play important roles, is considered to be one of the most promising candidates to realize the sufficient utilization of solar energy in a low-cost, green, and environmentally friendly manner. Interface engineering of semiconductor nanostructures has been qualified in the efficient improvement of PEC performances including three basic steps, i.e., light absorption, charge transfer/separation, and surface catalytic reaction. In this review, recently developed interface engineering of semiconductor nanostructures for direct and high-efficiency conversion of sunlight into available forms (e.g., chemical fuels and electric power) are summarized in terms of their atomic constitution and morphology, electronic structure and promising potential for PEC applications. Extensive efforts toward the development of high-performance PEC applications (e.g., PEC water splitting, PEC photodetection, PEC catalysis, PEC degradation and PEC biosensors) are also presented and appraised. Last but not least, a brief summary and personal insights on the challenges and future directions in the community of next-generation PEC devices are also provided.