An insight into the performance of CNT-based membrane with the application of electric field for distillation process

Abstract

The main drawbacks of conventional membrane distillation (MD) are particularly related to the membrane fouling, wherein the fouling development on the hydrophobic membrane surface was greatly affected by the decrement of temperature along the flow-direction. In this study, a composite membrane was fabricated by coating carbon nanotubes (CNT), and an electric-enhanced direct contact MD was developed subsequently with the application of alternating current potential (AC). Systematical analysis showed that the conventional MD system exhibited a great difference of fouling morphology from the feed inlet to outlet, and the variation of dominant communities from the Deinococcus − thermus to Proteobacteria. The AC application on the composite membrane exhibited a simultaneous anti-fouling and flux-enhancing property, which overcame the temperature drop and effectively maintained the membrane stability. Less foulants including the crystals and organics were observed, and the microbial richness and diversity obviously decreased, and the dominant bacteria composition was quite similar and single. Under the electrical field, better performance was expected due to the effects of hydrophilic surface, Joule heating and electrical function. We believe that the electrically conducting membrane has a promising potential in water treatment, paving the way for the smart design of novel MD systems.