Asymmetric oxygen-vacancy-engineered Co-MoO₃ nanoconfined catalytic membrane for deep organoarsenic removal

Arsenic-containing toxic agents are characterized by high toxicity and high mobility, posing significant environmental and public health hazards worldwide. Therefore, developing effective treatment materials and strategies represents a key research focus in sustainable processing technology. Herein, we developed a novel Co-MoO₃/GO confined catalytic membrane enriched with asymmetric oxygen vacancies for activating peroxymonosulfate (PMS) towards the efficient degradation of p-arsinic acid (p-ASA). Experimental characterization indicates that Co-MoO₃/GO membranes possess enhanced oxygen vacancies which, synergizing with electron-deficient Co reaction centers, shift the reaction pathway from a traditional radical mechanism to a predominant non-radical pathway. These membranes enable the selective generation of singlet oxygen (¹O₂) and exhibit resistance to external environmental factors (e.g., pH range of 2.0-10 and the presence of coexisting anions). The optimized Co-MoO₃/GO catalytic membrane/PMS system achieved 97.91 % removal of p-ASA within 1.0 min, exhibiting a degradation rate constant (k) of 23.79 s^-1, four orders of magnitude higher than that observed in traditional powder batch reactions (k = 0.082 min^-1). Furthermore, the Co-MoO₃/GO membrane demonstrated excellent regeneration capability, maintaining high functionality during 60 h of continuous operation. The leaching concentrations of cobalt and molybdenum ions were significantly below the permissible limit of 1.0 mg/L. These findings demonstrate that this work provides new insights into the design of efficient and stable catalytic membranes for advanced wastewater treatment applications.