Advanced electrically conductive carbon nanotubes-PVDF composite membranes with electro-promoted water treatment performance.

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.