以聚醚砜(PES)超滤膜为基膜,采用涂层法制备磺化聚醚醚酮(SPEEK)中空纤维复合纳滤膜,研究其对草甘膦的浓缩和去除。考察了该膜在浓缩草甘膦模拟废水中的操作条件,如跨膜压力、进料浓度、进料pH和离子强度等对通量和截留率的影响。结果表明,随跨膜压力的增加,草甘膦的截留率和水通量均增加,当跨膜压力由0.3 MPa增加到0.8 MPa时,水通量由34.0 L/(m2.h)增加至98.0 L/(m2·h),截留率高于98%;增加进料浓度和离子强度,截留率和通量均减小,当进料浓度由100 mg/L增至1 000 mg/L,水通量降低12.4%,截留率降低8.4%;而pH由3.0升至11.0时,截留率增加,但通量几乎不变。当把该膜材料用于浓缩含高浓度NaCl的草甘膦母液时,发现在0.5 MPa压力和pH=11.0下,复合纳滤膜对NaCl的截留率低于20%,对草甘膦的截留率可达90%。这说明该复合纳滤膜可以把草甘膦与NaCl有效分离开来,为草甘膦的回收利用提供了基础。
Glyphosate containing wastewater was treated by composite hollow fiber nanofiltration mem- branes. The composite membranes were prepared by coating polyethersulfone (PES) ultrafiltration (UF) mem- brane with sulfonated poly(ether ether ketone) (SPEEK). The effects of operational conditions, including trans- membrane pressure, feed concentration, feed pH, and feed ionic strength on the membranes performance were systematically studied for separating glyphosate. Results indicated that rejection and flux increased with the trans- membrane pressure. Both flux and glyphosate retention rate decreased with the increase of feed concentration and ionic strength. With the operation pressure increased from 0.3 to 0.8 MPa, the flux increased from 34.0 to 98.0 L/(m2 ~ h). With feed concentration increased from 100 mg/L to 1 000 mg/L, the water flux decreased 12.4% and the retention decreased 8.5%. The pH of the feed did not affect the water flux, but the rejection for glypho- sate increased significantly when solution pH increased from 3.0 to 11.0. The composite nanofihration mem- branes were used to concentrate the mother liquid of glyphosate containing NaC1 of a high concentration. It was found that at a trans-membrane of 0.5 MPa and pH = 11.0, NaC1 rejection was less than 20% and glyphosate re- tention rate was 90% , indicating that the membranes can effectively separate NaC1 and glyphosate, thereby pro- viding a potential treatment method for large-scale application in glyphosate recovery and reuse.