Advanced electrically conductive carbon nanotubes-PVDF composite membranes with electro-promoted water treatment performance
Yongke Zhang, Jiajian Xing, Gaoliang Wei, Linhua Rao, G. He, Hao Du, Haiguang Zhang, Xu Wang, Shuo Chen, Xie Quan
Abstract
Decentralized water supply is essential for providing clean and safe drinking water, especially in underdeveloped regions. Membrane technology is a key process for removing pathogens and suspended solids from polluted water sources. This study constructs electrically conductive membranes (ECMs) using carbon nanotubes (CNTs) confined within polarized poly(vinylidene fluoride) (PVDF) through C-F interactions. The resulting membranes achieve ultrahigh water permeance, 3.5 to 5.2 times higher than four commercial polymer membranes with similar pore sizes. They maintain good electrical conductivity and mechanical strength. Applying a weak negative potential induces electrostatic repulsion between the ECMs and foulants, enhancing antifouling performance by over 10 times in terms of backwashing interval compared to conventional polymer membranes. A demonstration project confirms the feasibility of industrial-scale production with a capacity of 11.5 m2 h−1, corresponding to an annual yield of approximately 100,000 m². Another field demonstration for drinking water treatment, with a capacity of 300 m3 day−1, shows improved effluent quality, 53% energy savings, and 95% cost reduction for chemical cleaning compared to conventional processes. This study provides a cost-effective and efficient solution for addressing drinking water security challenges in underdeveloped regions through the enhanced performance of CNTs-PVDF ECMs. Access to clean water is crucial, especially in underdeveloped areas. Here, authors develop electrically conductive membranes using carbon nanotubes and poly(vinylidene fluoride), achieving higher water permeance and improved antifouling, reducing costs and energy use