基于ZIF-8纳米粒子改性聚乙烯底膜的聚酰胺复合正渗透膜的制备和性能研究

Preparation and property of thin film composite polyamide(TFC-PA)forward osmotic(FO)membranes from polyethylene substrates modified with in situ grown ZIF-8 nano-particles

基于聚乙烯薄膜(PE)支撑材料,先通过浸涂Zn(Ⅱ)离子和2-甲基-咪唑配体溶液原位生长金属有机框架ZIF-8纳米粒子进行改性,然后进行间苯二胺和1,3,5-苯三甲酰氯的两次界面聚合,得到聚乙烯/聚酰胺(PE/PA)薄层复合正渗透(TFC-FO)膜PE/ZIF-8/PA^(2).考察了ZIF-8纳米粒子对所制备的PE/ZIF-8/PA^(2)TFC-FO膜的表面形貌结构、粗糙度、亲水性及正渗透性能的影响,并进一步研究了醇活化效应和水相共溶剂效应对生成的TFC-FO膜性能的影响.结果表明,ZIF-8中间层修饰后的聚乙烯底膜具有更大的粗糙度和更强的亲水性,两次聚合后得到的PE/ZIF-8/PA^(2)TFC-FO膜具有致密亲水和高比表面的聚酰胺分离层,优化后以去离子水为原料液、以浓度为1 mol/L NaCl为汲取液时,其水通量和反向盐通量分别为28.11 L/(m^(2)·h)和0.39 mol/(m^(2)·h).

Polyamide(PA)based thin film composite forward osmosis(TFC-FO)membranes were prepared from two-time interfacial polymerization(IP)processes between m-phenylene diamine(MPD)and trimesoyl chloride(TMC)on porous polyethylene(PE)substrates pre-modified with intermediate layers containing in situ grown ZIF-8 nano particles from the reaction of Zn(1)cations with 2-methylimidizole(2MIM)ligands.The impact of the ZIF-8 intermediate layers on the surface morphology,roughness,hydrophilicity and FO performance of the formed TFC-FO membranes were investigated.The effects from co-solvent modulation and from alcohol activation on the formed TFC-FO membranes were further studied.It was found that ZIF-8 modification could increase the surface roughness and hydrophilicity of the PE porous substrates,leading to the formation of PA layers with improved water flux and salt rejection rates.Under optimized conditions,the water flux of formed PE/ZIF-8/PA^(2) TFC-FO membranes reached 28.11 L/(m^(2).h)with a low reverse salt flux value of 0.39 mol/(m^(2).h)using 1 mol/L NaCl as drawing solution and pure water as feeding solution.