双分离层复合纳滤膜的制备及其性能
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摘要
以改性后的聚丙烯腈(PAN)超滤膜为基膜,依次采用层层自组装(LBL)和界面聚合的方法制备了具有双层分离层的复合纳滤膜。以间苯二胺(MPD)为水相单体,均苯三甲酰氯(TMC)为有机相单体,聚乙烯亚胺(PEI)为阳离子聚电解质,聚(4-苯乙烯磺酸钠)(PSS)为阴离子聚电解质,探索了LBL条件对双分离层复合纳滤膜性能的影响,考察了通过不同制备方法获得的纳滤膜对硫酸镁(MgSO_4)的分离性能,得到了最佳的LBL制备条件:PEI溶液的浓度为1.00 g·L~(-1),pH为7;PSS溶液的浓度为1.00 g·L~(-1),p H为10,支撑电解质氯化钠(NaCl)浓度为1.00 mol·L~(-1),单一聚电解质(PEI或PSS)的沉积时间为20 min。与仅通过界面聚合法制得的聚酰胺纳滤膜相比,在界面聚合反应之前,先通过LBL沉积1.5层的聚电解质层时得到的复合纳滤膜分离性能优异稳定,在0.80 MPa的压力下,过滤2.00 g·L~(-1)MgSO_4溶液时的通量为18.6 L·(m~2·h)~(-1),截留率达到99.07%。
Composite nanofiltration membrane with double separation layers was prepared through combined layer-by-layer(LBL) self-assembly and interfacial polymerization methods using hydrolyzed polyacrylonitrile(PAN)ultrafiltration membrane as support. M-phenylenediamine(MPD) and trimesoyl chloride(TMC) were used as aqueous monomer and organic monomer, respectively. Polyethyleneimine(PEI) and sodium polystyrene sulfonate(PSS)were chosen as cationic polyelectrolyte and anionic polyelectrolyte, respectively. The effects of LBL self-assembly conditions on the performance of double-separation-layer composite nanofiltration membranes were investigated.The separation characteristics of nanofiltration membranes which prepared through different fabrication methods for MgSO_4 were evaluated. The optimum LBL conditions were the concentration of 1.00 g·L~(-1) and pH of 7 of PEI solution, respectively. The concentration and p H of PSS solution were 1.00 g·L~(-1) and 10, respectively. Supported electrolyte(Na Cl) concentration was 1.00 mol·L~(-1). The deposition time of one kind of polyelectrolyte(PEI or PSS)was 20 min. Compared with polyamide nanofiltration membrane prepared by using simple interfacial polymerization method, the double-separation-layer composite nanofiltrationmembrane which prepared through firstly depositing 1.5 polyelectrolyte layers and followed by interfacial polymerization had better and stable separation properties. Under the pressure of 0.80 MPa, the flux of double-separation-layer composite nanofiltration membrane was 18.6 L·(m~2·h)~(-1) and the retention rate reached 99.07% when filtering 2.00 g·L~(-1) magnesium sulfate solution.
Composite nanofiltration membrane with double separation layers was prepared through combined layer-by-layer(LBL) self-assembly and interfacial polymerization methods using hydrolyzed polyacrylonitrile(PAN)ultrafiltration membrane as support. M-phenylenediamine(MPD) and trimesoyl chloride(TMC) were used as aqueous monomer and organic monomer, respectively. Polyethyleneimine(PEI) and sodium polystyrene sulfonate(PSS)were chosen as cationic polyelectrolyte and anionic polyelectrolyte, respectively. The effects of LBL self-assembly conditions on the performance of double-separation-layer composite nanofiltration membranes were investigated.The separation characteristics of nanofiltration membranes which prepared through different fabrication methods for MgSO_4 were evaluated. The optimum LBL conditions were the concentration of 1.00 g·L~(-1) and pH of 7 of PEI solution, respectively. The concentration and p H of PSS solution were 1.00 g·L~(-1) and 10, respectively. Supported electrolyte(Na Cl) concentration was 1.00 mol·L~(-1). The deposition time of one kind of polyelectrolyte(PEI or PSS)was 20 min. Compared with polyamide nanofiltration membrane prepared by using simple interfacial polymerization method, the double-separation-layer composite nanofiltrationmembrane which prepared through firstly depositing 1.5 polyelectrolyte layers and followed by interfacial polymerization had better and stable separation properties. Under the pressure of 0.80 MPa, the flux of double-separation-layer composite nanofiltration membrane was 18.6 L·(m~2·h)~(-1) and the retention rate reached 99.07% when filtering 2.00 g·L~(-1) magnesium sulfate solution.
引文
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[3]韩姗姗.基于配位作用的层层自组装纳滤膜的制备及性能研究[D].青岛:中国海洋大学,2012.
[4]DECHER G.Toward layered polymeric multicomposites[J].Science,1997,227(5330):1232-1237.DOI:10.1126/science.277.5330.1232.
[5]计艳丽,安全福,钱锦文,等.聚电解质层层自组装纳滤膜[J].化学进展,2010,22(1):119-124.
[6]张聪.静电层层自组装法制备PAN/PEI/GO液体分离膜及其性能研究[D].哈尔滨:哈尔滨工业大学,2016.
[7]邓慧宇,徐又一,朱宝库,等.聚电解质层层自组装制备PV、NF膜研究进展[J].功能材料,2007,38(8):1217-1220.
[8]DECHER G,HONG J D,SCHMIT T J.Buildup of ultrathin multilayer films by a self-assembly process:Ⅲ.Consecutively alternating adsorption of anionic and cationic polyelectrolytes on charged surfaces[J].Thin Solid Films,1992,210-211(2):831-835.DOI:10.1016/0040-6090(92)90417-A.
[9]王磊,刘婷婷,米娜,等.PDA/PIP二胺混合聚酰胺复合纳滤膜制备及性能表征[J].西安建筑科技大学学报(自然科学版),2015,47(1):108-114.DOI:10.15986/j.1006-7930.2015.01.021.
[10]方鹏,曹兵,淡宜,等.界面聚合法制备聚酰胺纳滤膜及工艺条件对纳滤膜性能的影响[J].高分子材料科学与工程,2011,27(10):1-3.
[11]李博群.荷电聚砜超滤膜层层自组装改性制备纳滤膜及其脱盐性能研究[D].武汉:武汉工程大学,2015.
[12]闫海红.聚丙烯腈膜改性及动态LBL组装聚离子膜的研究[D].北京:北京工业大学,2007.
[13]呼佳瑞.聚酰胺复合纳滤膜的制备与表征[D].西安:西安建筑科技大学,2014.
[14]立卿,王磊,王旭东.纳滤膜物化特征对膜分离及膜污染影响研究[J].水处理技术,2009,35(1):24-29.
[15]ZHANG Y,SU Y,PENG J,et al.Composite nanofiltration membranes prepared by interfacial polymerization with natural material tannic acid and trimesoyl chloride[J].Journal of Membrane Science,2013,429:235-242.DOI:10.1016/j.memsci.2012.11.059.