共烧结法制备梯度致密化Al2O3中空纤维膜

Study on the preparation of gradient-dense Al_2O_3 hollow fiber membranes by co-sintering process

用实验室自制的Al2O3中空纤维膜为基膜,以Al2O3粉末分散液和Al粉分散液为原料,用真空抽滤法与浸渍法制备过渡层,再浸涂勃母石溶胶,烧结形成梯度致密化Al2O3中空纤维膜.讨论了梯度致密化Al2O3中空纤维膜的形貌、泡点压力、膜孔径与渗透性能等因素.结果表明,造成膜性能差异的主要原因有:(1)Al2O3粉末与Al粉的熔点差异;(2)真空抽滤形成的滤饼与浸涂形成的吸附层之间的厚度差.同时,所制得的梯度致密化Al2O3中空纤维膜纯水通量为17～2 990L/(m2.h.0.1MPa),平均孔径为0.04～0.52μm.

Using self-prepared Al2O3 hollow fiber membranes as the substrates, Al2O3 and A1 aqueous sus- pensions were used as materials for the intermediate layer of gradient-dense Al2O3 hollow fiber membranes by vacuum filtration and dipping method respectively. Then the obtained membranes with intermediate layers from the two suspensions by two coating methods were modified by self-prepared boehmite sol and gradient-dense Al2O3 hollow fiber membranes were obtained after a sintering process. The morphology, bubble point pressure, maximum pore size and permeation property of the membranes were discussed. The results indicated there were two main reasons for the difference among membrane performances： （1） the melting temperature difference between Al2O3 and A1 powders; （2） the thickness difference between the formed cake during the filtration process and the adsorption layer of the aqueous solutions by dipping method. The pure water flux and mean pore size of the prepared gradient-dense Al2O3 hollow fiber mem- branes are 17-2 990 L/（m^2 ·h ·0. 1 MPa） and 0. 04-0. 52μm, respectively.