Effect of on the Membrane Distillation of PVDF Membrane Material Enhanced by Gas-Liquid Two-Phase Flow

Abstract

Dashuai Zhang, Xiaopeng Zhang, YuqinXiong, Di Wu, ZaifengShi, QiangLin Fan Zhou, Fei Gao, Lixin Zhou, Xueying Cheng, Yunjuan Pu

This study investigates the membrane performance and fouling control in the bubble-assisted sweeping gas membrane distillation with high concentration saline (333 K saturated solution) as feed. The results show that longer bubbling interval (3 min) at a fixed bubbling duration of 30 s can most efficiently increase the flux enhancement ratio up to 1.518. Next, the flux increases with the gas flow rate under a relatively lower level, but tends to a plateau after the threshold level (1.2 L•min-1). Compared to non-bubbling case, the permeate flux reaches up to 1.623 fold at a higher bubble relative humidity of 80 %. It was also found that greater flux enhancement can be achieved and meanwhile dramatic flux decline can be delayed for an intermittent bubbling system with a smaller nozzle size. These results accord well with the observations of fouling deposition in situ on the membrane surface with SEM.

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