Surface nano-structuring of reverse osmosis membranes via atmospheric pressure plasma-induced graft polymerization for reduction of mineral scaling propensity
Surface nano-structuring of reverse osmosis membranes via atmospheric pressure plasma-induced graft polymerization for reduction of mineral scaling propensity
复制标题
DOI：
10.1016/j.memsci.2010.02.053
复制
发表时间：
2010-05-15
影响因子：
9.5
通讯作者：
Cohen, Yoram
中科院分区：
文献类型：
--
作者：
Kim, Myung-man;Lin, Nancy H.;Cohen, Yoram
用亲水性聚甲基丙烯酸对聚酰胺脱盐膜进行表面纳米结构处理，可以减少膜的矿物结垢倾向，如用二水硫酸钙(石膏)所证实的那样。采用两步法合成了聚酰胺(PA)薄膜复合膜，其活性聚酰胺(PA)层用撞击大气压等离子体活化，然后在60℃、初始单体浓度为5-20%(v/v)的条件下，将水溶性甲基丙烯酸(MAA)单体溶液接枝聚合到PA-TFC膜表面。首次开发了一种端接枝聚甲基丙烯酸(PMAA)表面链的方法，并使用界面聚合到涂覆在硅片上的聚乙烯亚胺(PEI)薄膜上的替代聚酰胺膜对其进行了评价。得到的PMAA-PA-PEI-Si代理膜表面亲水性好，水接触角范围为10-17度。在相同的FRGP反应条件下，PA-TFC膜的结构比具有相似表面粗糙度(类似于70 nm)和盐截留率的商品反渗透膜具有更高的透过率(1.3-2.26倍)。膜矿物结垢通量试验表明，与相同盐分截留率的商品膜相比，膜矿物结垢倾向可以显著降低，同时产生等量或更高的透水率。对于最佳的膜表面(以10%(v/v)的初始MAA浓度制备)，石膏结垢的起始时间相对于商品反渗透膜延迟2-5倍。目前正在进行进一步优化表面结构的工作，以提高抗结垢能力，并评估表面结构对矿物盐晶体成核的影响。(C)2010爱思唯尔B.V.保留所有权利。
Surface nano-structuring of polyamide desalination membrane with a hydrophilic poly(methacrylic acid) was shown to reduce the membrane mineral scaling propensity as demonstrated with calcium sulfate dihydrate (gypsum). A two-step approach was employed, whereby the active polyamide (PA) layer of a thin-film composite (TFC) synthesized membrane was activated with impinging atmospheric plasma, followed by a solution free-radical graft polymerization (FRGP) of a water soluble methacrylic acid (MAA) monomer, at 60 C and initial monomer concentration of 5-20% (v/v), onto the surface of the PA-TFC membrane. The approach of creating a layer of end-grafted poly(methacrylic acid) (PMAA) surface chains was first developed and evaluated using a surrogate polyamide membrane layer interfacially polymerized onto a thin poly(ethyleneimine) (PEI) film coated onto a silicon wafer. The resulting PMAA-PA-PEI-Si surrogate membrane surface was hydrophilic with a water contact angle range of 10-17 degrees. Structuring of the PA-TFC membrane at equivalent FRGP reaction conditions resulted in membranes of higher permeability (by a factor of 1.3-2.26) relative to a commercial RO membrane of a similar surface roughness (similar to 70 nm) and salt rejection. Flux tests of membrane mineral scaling demonstrated that membrane mineral scaling propensity can be measurably reduced, relative to commercial membrane of the same salt rejection, while yielding equivalent or higher water permeability. The onset time for gypsum scaling for the optimal membrane surface (prepared at 10% (v/v) initial MAA concentration) was retarded by a factor of 2-5 relative to the commercial RO membrane. Current work is ongoing to further optimize the surface structure in order to increasing scaling resistance and assess the impact of surface structuring on nucleation of mineral salt crystals. (C) 2010 Elsevier B.V. All rights reserved.