Preparation of supported zirconia ultrafiltration membranes with the aid of polymeric additives
Preparation of supported zirconia ultrafiltration membranes with the aid of polymeric additives
复制标题
高分子助剂负载型氧化锆超滤膜的制备
DOI：
10.1016/j.memsci.2009.11.009
复制
发表时间：
2010-02-15
影响因子：
9.5
通讯作者：
Xu, Nanping
中科院分区：
文献类型：
--
作者：
Qiu, Minghui;Fan, Yiqun;Xu, Nanping
陶瓷薄膜在干燥过程中破裂是一个众所周知的现象。已有文献表明，除非添加聚合物添加剂来改善临界裂纹厚度，否则在无孔衬底上浇注的薄膜将会开裂。本文研究了用湿化学法在多孔衬底上制备无裂纹氧化锆膜，重点研究了聚合物添加剂对临界裂纹厚度和膜性能的影响。采用四种添加剂制备氧化锆浆，粘度、粒度分布和沉降量测试表明，聚乙烯醇(PVA)和甲基纤维素(MC)有利于制备稳定的可剪裁包衣浆料。干燥实验还表明，在使用PVA或MC作为添加剂的情况下，膜干燥过程中失重平稳，裂纹形成的风险较低。在悬浮液中进一步加入0.25wt%的PVA，与单独添加0.75wt%MC的聚合物相比，临界裂纹厚度从4.0µm增加到5.0µm，有利于制备无裂纹膜。当膜厚控制在临界裂纹厚度以下时，制得的膜表面更均匀光滑，缺陷或裂纹更少。对于厚度约为3-4微米的膜，纯水渗透率达到1000Lm(-2)h(-1)bar(-1)，葡聚糖截留率达85%。(C)2009爱思唯尔B.V.保留所有权利。
Cracking of ceramic films during drying is a well-known phenomenon. Literatures have shown that films cast on the nonporous substrates will crack unless polymeric additives are added to improve the critic crack thickness. This paper investigates the fabrication of crack-free zirconia membranes on porous substrate through a wet chemical method, with a focus on the influence of polymeric additives on the critical crack thickness and membrane performances. Four types of additives were used in the preparation of zirconia slurries, and polyvinyl alcohol (PVA) and methylcellulose (MC) were favorable for a stable, ready-to-clip-coating slurry suggested by viscosity, particle size distribution and sedimentation measurements. Drying experiments also showed that there was a smooth weight loss and a low risk of crack-formation during membrane drying in the case of using PVA or MC as additives. Compared with a sole polymer additive of 0.75 wt% MC, the critical crack thickness increases from 4.0 mu m to 5.0 mu m when 0.25 wt% PVA was further introduced into the suspension, which benefits the preparation of crack-free membranes. When the membrane thickness was controlled to be thinner than the critical crack thickness, the prepared membrane would be more likely to have a homogeneous and smooth surface, and less defects or cracks. For the membrane with a thickness of approximately 3-4 mu m, the pure water permeability reached 1000 Lm(-2) h(-1) bar(-1) and the dextran rejections were up to 85%. (C) 2009 Elsevier B.V. All rights reserved.