Defect-engineered Cu-TCPP/ZIF-L nanosheet-modified PVDF membrane with enhanced water purification and dye removal performance

Defect-engineered Cu–TCPP/ZIF-L nanosheet membrane: tannic acid coordinates with Cu 2+ to create defect sites, while ZIF-L serves as an interlayer spacer to suppress π–π stacking and restore transport. • The optimized membrane achieves 691.20 L·m -2 ·h -1 ·bar -1 , a 75.5× increase over pristine Cu–TCPP. • Efficient dye removal under static conditions: 97.77% (CV) and 97.87% (MG), suitable for agricultural water purification. • Adsorption–degradation self-cleaning via single-layer chemisorption/ion exchange and catalytic oxidation by O₂· - / 1 O₂; cucumber seedling tests confirm irrigation safety. Dye-laden wastewater from aquaculture and agricultural runoff poses serious environmental challenges, calling for membranes that can deliver both high water flux and efficient dye removal. However, MOF-based composite membranes often still face trade-offs between permeance and separation efficiency, and their practical performance is limited by fouling and insufficient self-regeneration. We hypothesize that defect engineering of Cu–TCPP via tannic-acid-mediated metal–phenolic network (MPN) disruption, together with ZIF-L nanosheet interlayer modulation, can create favorable transport pathways and strengthen adsorption/ion-exchange interactions while enabling ROS-driven self-cleaning. A defect-engineered Cu–TCPP/ZIF-L nanosheet-modified PVDF membrane was prepared using an MPN strategy with tannic acid, and its dye removal performance toward malachite green and crystal violet, together with the underlying mechanisms, was systematically investigated. The optimized membrane achieves a 75.5-fold increase in water permeance to 691.20 L/(m 2 ·h·bar) while maintaining high removal efficiencies of 97.87% for malachite green and 97.77% for crystal violet, and it exhibits self-cleaning behavior enabled by superoxide radicals and singlet oxygen. This work demonstrates an integrated Cu-TCPP–TA/ZIF-L/PVDF membrane design that combines MPN-mediated defect regulation with ZIF-L-assisted lamellar structure modulation for adsorption–degradation-based dye removal in agricultural water-related scenarios. Download: Download high-res image (170KB) Download: Download full-size image