超声波在线监测纳滤膜无机污染

Monitoring of inorganic fouling on nanofiltration membrane using ultrasonic time-domain reflectometry technique

针对商业用纳滤膜,分别使用1.2 g/L和2.4 g/L的CaSO4溶液作为料液,采用超声波时域反射法在线监测纳滤膜的污染过程.结果表明:1.2 g/L CaSO4过滤过程中,初期膜通量下降是由浓差极化所致,污染4 h后开始有CaSO4的沉积;2.4 g/L CaSO4为饱和溶液,在污染初期CaSO4晶体就在膜面上快速沉积,所以其通量大幅度下降;此外,CaSO4晶体随着污染时间的延长逐渐增多、变大,有增长的趋势.超声监测结果与膜通量变化、比重法和SEM分析结果具有良好的对应关系.

An ultrasonic time-domain refleetometry technique has been employed to monitor of inorganic fouling on nanofiltration（NF） membrane. The feed used is 1,2 g/L and 2.4 g/L CaSO4 solutions. The NF membrane used in this study is a commercial membrane （XLE）. The initial flux decline is attributed to concentration polarization during the fouling operation carried out with 1,2 g/L CaSO4. The flux declines rapidly at the initial stage as a result of CaSO4 deposition on the membrane during the fouling operation carried out with 2.4 g/L CaSO4. Further, the growth of CaSO4 crystals deposited on the membrane surface with the operation time has been observed, Moreover, the ultrasonic measurements are in good agreement with the independent measurements such as the flux-decline data, weight and SEM analyses.