Challenges and Perspectives on Photocatalytic Membrane Reactors for Volatile Organic Compounds Degradation and Nitrogen Oxides Treatment

Air pollution is a pressing environmental and public health issue, with volatile organic compounds (VOCs) and nitrogen oxides (NO_x) being among the most hazardous airborne pollutants. Photocatalytic membrane reactors (PMRs) have emerged as a promising technology for air purification due to their ability to integrate photocatalytic degradation and membrane separation in a single system. This paper provides a comprehensive review of the advancements, challenges, and future prospects of PMR technology for VOC degradation and NO_x treatment. Various photocatalytic membranes and their fabrication techniques, including material selection, structural modifications, and catalyst immobilization strategies, are critically analyzed. The study further explores different PMR configurations, operational parameters, and their efficiency in air treatment applications. A theoretical PMR test system is also presented to evaluate design optimization strategies. Despite its potential, challenges such as membrane fouling, catalyst deactivation, and scale-up limitations remain critical barriers to widespread adoption. Future trends focus on enhancing photocatalytic performance, developing cost-effective materials, and optimizing reactor designs to facilitate large-scale industrial applications of PMRs.