以TiO2纤维制备陶瓷微滤膜的研究--制膜液pH对膜孔径的影响

Preparation of ceramic microfiltration membrane with TiO_2 ceramic-fiber:effect of suspension pH values on pore sizes of membrane

以陶瓷纤维堆积构成的多孔膜材料，可以克服传统过滤材料过滤阻力大的缺点．在使用浸浆法以TiO2陶瓷纤维为原料制备陶瓷微滤膜的过程中，通过调节制膜液的pH，制备孔径在1．3—2．2μm之间的系列微滤膜．采用气体泡压、渗透性能、环境扫描电镜、zeta电位分析等手段对膜的微结构及性能进行表征，分析pH对zeta电位的影响．结果表明：含TiO2纤维的制膜液等电点位于pH=4．1附近；随着pH的增加，TiO2纤维之间的相互排斥力越大，排列也越松散，膜层孔径变大；膜的N2与纯水通量与孔径有着良好的对应关系．

Microfihration membrane prepared with ceramic fibers could solve the high resistance problem of traditional filtration materials. A series of membrane samples, pore size ranged from 1.3 to 2.2 μm, could be obtained by adjusting of suspension pH values in preparation process of the microfiltration membrane with TiO2 fibers by dipcoating. The membrane microstructure and the performance were characterized by the gas bubble pressure method, scaning electron microscope （SEM） and gas/water flux, and the influence mechanism of suspension pH values on zeta potential was discussed. Experimental results show that the isoelectric point of TiO2 suspension is about pH = 4. 1. The larger the repulsive force of TiO2 fibers, the looser the arrangement, thus it leading to a larger membrane pore size. The result demonstrates that the water and the gas-flux are related well with membrane pore sizes.