Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202509020
The AAOA-MBR (anaerobic-anoxic-oxic-anoxic membrane bioreactor) process is widely used in municipal wastewater treatment, but its multi-stage internal recirculation complicates sludge retention time (SRT) and carbon source distribution. This study systematically regulated three reflux ratios (R1: membrane tank to oxic tank; R2: oxic tank to anoxic I tank; R3: anoxic II tank to anaerobic tank) in a pilot-scale system (0.24 m3·d−1) to reveal their effects on nutrient removal and membrane fouling. When R1:R2:R3 = 300%:200%:100%, effluent COD, TN, TP, and NH3-N met discharge standards. Reducing R1 and R2, thereby decreasing total reflux ratio from R=6 to R=3, shortened SRT, which suppressed nitrifier accumulation and increased effluent COD and TN, but decreased TP. High-throughput sequencing of anoxic I and oxic tanks showed that denitrifying bacteria (Thauera and Ottowia) relative abundances decreased from 0.68% to 0.42% and 0.51% to 0.24%, respectively, while the phosphorus-accumulating organism Candidatus_Accumulibacter increased from 0.78% to 1.12%, enhancing phosphorus removal. Additionally, lowering R1 to 200% caused sludge accumulation in the membrane tank, exacerbating membrane fouling. Thus, internal recirculation ratios must be adjusted based on influent characteristics to balance nutrient removal and membrane performance.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.1016/S1872-5813(26)60654-8
The declining costs of renewable energy are progressively improving the economic viability of employing electrochemical techniques for carbon dioxide capture. Electrochemical carbon capture (ECC) technology utilizes electrical energy to drive electrode reactions, enabling the selective separation of CO2. The vigorous development of ECC powered by renewable energy offers a promising alternative route to conventional carbon capture methods, overcoming limitations associated with thermally driven capture and release cycles. This approach provides a promising alternative route that is more efficient, flexible, scalable, low-energy-consuming and low-polluting for traditional carbon capture technologies. This review begins by introducing established, large-scale carbon capture technologies, such as pre-combustion capture, post-combustion capture, oxy-fuel combustion, adsorption, membrane separation and the calcium looping process. It then transitions to several rapidly developing ECC technologies, including electrochemically mediated amine regeneration (EMAR), pH-swing-mediated systems, and methods involving redox-active molecules. The pH-swing systems are further categorized into bipolar membrane electrodialysis (BMED), proton-coupled electron transfer (PCET), and membrane capacitive deionization (MCDI). For each method, the underlying principles, technological advancements, advantages, as well as current problems and challenges, are systematically elucidated. It is anticipated that with the widespread deployment of green electricity and persistent innovation in electrochemical materials, ECC technology will emerge as a highly efficient and low-carbon strategy, contributing significantly to the global goal of achieving carbon neutrality.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4082-6
High-performance nonvolatile memory devices are crucial for next-generation computing, yet achieving low-power, stable, and reproducible resistive switching remains challenging, primarily due to stochastic filament formation and limited precise control over the electronic properties of active materials. Herein, we employ a rational molecular engineering strategy to address these limitations by constructing a series of two-dimensional pyrene-based covalent organic frameworks (Py-COFs)—Py-H, Py-CH3, and Py-OH—via systematic substitution (–H, –CH3, and –OH) on the phenyl linkers to modulate backbone electronics. The electron-donating –CH3 and –OH motifs enrich the π-conjugated backbone with higher electron density, while the –OH moiety in Py-OH further engages in p-π conjugation with the benzene ring and forms intramolecular hydrogen bonds, thereby increasing framework rigidity, enhancing orbital overlap, and promoting charge delocalization. Enabled by these structural refinements, Py-OH-based devices exhibit markedly improved resistive switching behavior, characterized by a low operating voltage, an ON/OFF ratio of ~10^3.45, and excellent retention stability. Combined photophysical, electrochemical, and high-resolution TEM analyses corroborate that hydroxyl-driven p-π conjugation, hydrogen-bond reinforcement, and the emergent nanowire-like morphology synergistically suppress uncontrolled filament formation and promote efficient charge transport. These findings establish a clear structure-property correlation in functionalized Py-COFs and underscore their promise as tunable active layers for low-power, high-performance resistive memory and neuromorphic computing.