Research of conductive membrane distillation

Abstract

Membrane distillation is an energy-saving technology that utilizes low-grade energy to treat highly saline water, however, the current use of the technology is faced with serious membrane fouling, wetting and other problems. Conductive membranes have received attention in recent years for the ability of alleviating the problems of fouling, wetting and temperature polarization in membrane distillation under the influence of the electrostatic repulsion, electrochemical redox and Joule heating brought about by the applied electric field. The structure, principle and research progress of membrane distillation were summarized, with emphasis on introducing and comparing the structure, action mechanism and characteristics of capacitive mode, resistive mode and alternating current mode operation in membrane distillation. The capacitive mode mainly solved the fouling and wetting problems through electrostatic repulsion, electrochemical redox, and electrically induced bubbles, while the resistive mode created higher vapor pressure and pure water flux through higher voltage and reduced biofouling through Joule heating, and the alternating current mode prevented the formation of contamination through the exchange of polarity, which made the fouling layer loose. Finally, the treatment efficacy, anti-fouling efficacy, anti-wetting efficacy and anti-temperature polarization of the conductive membrane distillation were elaborated, providing a reference for the application and development of the conductive membrane distillation in engineering.

Keywords

• membrane distillation
• conductive membrane
• membrane fouling
• membrane wetting