MOF原位生长改性聚对氯甲基苯乙烯-聚偏氟乙烯正渗透复合膜及其对乳化油废水的抗污染性  

MOF in-situ growth modified poly(p-chloromethyl styrene)-polyvinylidene fluoride forward osmosis composite membrane and its anti-fouling performance for emulsified oil wastewater

作　　者：陈芬[1] 杜春慧[1] 胡锦泰 吴春金[1] CHEN Fen;DU Chunhui;HU Jintai;WU Chunjin(School of Environmental Science and Engineering,Zhejiang Gongshang University,Hangzhou 310018,China)

机构地区：[1]浙江工商大学环境科学与工程学院,杭州310018

出　　处：《复合材料学报》2023年第4期2075-2084,共10页Acta Materiae Compositae Sinica

基　　金：浙江省基础公益研究计划项目(LGF21E080008)。

摘　　要：金属-有机框架(MOF)材料有望提高正渗透(FO)膜的水通量和抗污染性,以提高其对乳化油废水的分离性能。为将MOF引入FO膜,首先通过相转化法制备聚对氯甲基苯乙烯-聚偏氟乙烯(PCMS-PVDF)共混底膜,以底膜中的氯甲基基团(-CH_(2)Cl)为反应位点与2-甲基咪唑(Hmim)中的仲胺或叔胺反应,接着与硝酸锌(Zn(NO3)2)反应,以在膜表面原位生长金属有机骨架沸石咪唑酯骨架-8(ZIF-8),最后经界面聚合制备抗污染FO复合膜。通过SEM、XPS、FTIR和接触角测定仪等对底膜和FO膜的表面化学结构及膜亲/疏水性能等进行表征。结果表明:ZIF-8均匀生长在PCMS-PVDF底膜表面,且该纳米粒子为形状较规则的立方晶体。由于ZIF-8的存在使底膜表面较疏水,但界面聚合后形成的聚酰胺层重新使膜表面变为亲水。对膜的渗透分离和抗污染性研究表明,在FO模式下,以1 mol/L的NaCl为汲取液时,未经ZIF-8改性的FO膜(PCMS-PVDF-FO)水通量仅为12.4 L·m^(−2)·h^(−1),而经过ZIF-8改性后的FO膜(ZIF-8/PCMS-PVDF-FO)水通量可达到20.7 L·m^(−2)·h^(−1)。对乳化油模拟废水分离实验表明,经过4次纯水-乳化油分离循环后,正渗透膜ZIF-8/PCMS-PVDF-FO的纯水通量恢复率仍保持在89.9%,总污染率为27.5%;而相同情况下PCMS-PVDF-FO的通量恢复率仅为66.9%,总污染率上升为66.2%。综上,经过ZIF-8原位生长改性的正渗透复合膜在乳化油废水分离方面表现出较优异的性能。Metal-organic framework(MOF)material is expected to improve the water flux and antifouling property of forward osmosis(FO)membrane,and improves its separation performance to emulsified oil wastewater.In order to introduce MOF into FO membrane,poly(p-chloromethyl styrene)-polyvinylidene fluoride(PCMS-PVDF)blend substrate was prepared by phase inversion method.The chloromethyl group(−CH_(2)Cl)in the substrate reacted with secondary or tertiary amine in 2-methylimidazole(Hmim),and then reacted with zinc nitrate(Zn(NO3)2).The antifouling FO membrane was prepared by in-situ growth of metal-organic zeolite imidazolium ester skeleton-8(ZIF-8)and interfacial polymerization.The surface chemical structures and hydrophilic/hydrophobic property of substrate membrane and FO membrane were characterized by SEM,XPS,FTIR,contact angle analyzer and so on.The results show that ZIF-8 grows uniformly on the surface of PCMS-PVDF substrate,and the nanocrystals are cubic crystals with regular shape.Due to the presence of ZIF-8,the substrate surface is hydrophobic,but the new polyamide layer formed by interfacial polymerization makes the membrane surface hydrophilic again.The results show that the water flux of the FO membrane(PCMS-PVDF-FO)without ZIF-8 modification is only 12.4 L·m^(−2)·h^(−1),but the FO membrane(ZIF-8/PCMS-PVDF-FO)modified with ZIF-8 reach 20.7 L·m^(−2)·h^(−1)when using 1 mol/L NaCl as the drawing solution in FO mode.The separation experiment of emulsified oil simulated wastewater shows that the recovery ratio of pure water flux of FO membrane(ZIF-8/PCMS-PVDF-FO)is remained 89.9%,the total fouling ratio is 27.5%after running four cycles for pure water-emulsified oil separation.But under the same condition,the flux recovery rate of PCMS-PVDF-FO is only 66.9%,and the total fouling ratio increases to 66.2%.Based on the above,it can be seen that the FO composite membrane modified by in-situ growth of ZIF-8 exhibits excellent performance in emulsified oil wastewater separation.

关 键 词：原位生长 ZIF-8 聚偏氟乙烯 正渗透复合膜 乳化油分离 MOF 抗污染性 

分 类 号：TQ028.8[化学工程]