Electric cavity-enhanced catalytic membranes for micropollutant removal in wastewater

Abstract

An urgent need exists for a green and energy-efficient method for ultra-rapid micropollutant removal from wastewater. Exploring the use of membrane-in-electric cavity system for pharmaceutical decomposition on seconds timescale presents a compelling yet novel approach. An effective photocatalytic membrane with interconnected inner cavities, composed of TFPT-TAPT-COF and NH₂–Ti₃C₂T_x (NTCM), was synthesized using 3-aminopropyltriethoxysilane mediated self-assembly method. Theoretical analysis confirms a charge transfer number of approximately 2.7 |e| within the heterojunction, creating strong built-in electric fields within the cavity walls. In single-pass flow-through wastewater treatment, the NTCM membrane achieved up to 95.4 % removal of norfloxacin, with a disappearance rate of 2.45 × 10⁻⁴ mol m⁻¹ s⁻¹, within a residence time of 3.42 s under 70 mW cm⁻² light irradiation and a flow rate of 1 mL min⁻¹. This exceptional efficiency is attributed to the complete separation and swift transfer of photoinduced carriers, which significantly amplifies the likelihood of collisions with micropollutants and facilitates their removal within the confined space of the dynamic convective flow, thereby enhancing the overall pollutant degradation process. Additionally, the NTCM membrane's self-oxygenating feature allows it to effectively treat a range of wastewater substrates, including near-neutral wastewater, fulvic acid, and charged ion species. However, carbonate ions significantly inhibit norfloxacin removal. Overall, this study introduces a cost-effective, high-efficiency, and low-energy approach to micropollutant removal in wastewater treatment.