Progresses of advanced anti-fouling membrane and membrane processes for high salinity wastewater treatment

Membrane fouling during the high salinity wastewater treatment is a critical bottleneck restricting the sustainable application of membrane technologies. Developing advanced anti-fouling membranes and membrane processes is necessary, promising to solve the problem fundamentally and economically. Herein, this review focuses on nanofiltration (NF), reverse osmosis (RO) and membrane distillation (MD) applied for the high salinity wastewater treatment, and contrastively reviews membrane fouling processes and developing strategies of anti-fouling membranes and membrane processes. Types of foulants and membrane fouling mechanisms in different membrane processes are discussed, involving the most recent anti-fouling theory, and the difference caused by the separation mechanism, membrane property and operating condition is emphasized. Based on this understanding, to the material, the design and preparation of advanced anti-fouling membranes in NF, RO and MD process for different membrane foulants are reviewed. Then to the process intensification, the applications of external assistances such as the bubbling, ultrasonic, electric field and magnetic field for enhancing anti-fouling performance are also presented. Finally, the research status and existing problems in developing sustainable membrane processes are summarized, and future research needs are prospected. This review is expected to provide a valuable reference in the development of advanced membrane processes with improved sustainability for treating the high salinity wastewater.