超疏水CF4等离子体改性PVDF膜及其DCMD性能

摘要

To improve the membrane hydrophobicity, CF4 plasma surface modification was used to modify the home-made polyvinylidene fluoride ( PVDF) membranes by chemical vapor deposition. Superhy-drophic membranes with a water contact angle of 169.5° ±4.9° were obtained. The superbydrophic PVDF membrane was tested in direct contact membrane distillation (DCMD) with 4% NaCl solution. Results showed that the water permeation was 26. 5 kg/( m2 ·h), and the NaCl rejection was 99. 976 6% at a feed temperature of 70. 5 ℃,.%采用低温CF4等离子体技术,通过化学气相沉积,将一般疏水聚偏氟乙烯(PVDF)膜表面成功改性为接触角为169.5°±4.9°的超疏水表面,研究改性后的超疏水膜的直接接触式膜蒸馏(DCMD)过程.结果表明:当进料液为4％的NaCl溶液时,高温侧温度70.5℃,改性膜通量为26.5 kg/(m2·h),截留率高达99.976 6％.