高通量海水淡化用纳米纤维复合膜微结构设计与调控

项目名称： 高通量海水淡化用纳米纤维复合膜微结构设计与调控

项目编号： No.20874009

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 王雪芬

作者单位： 东华大学

项目金额： 34万元

中文摘要： 本课题从纳米纤维基膜/中间过渡层/超薄功能皮层三层结构复合滤膜制备入手，在纳米纤维多孔基膜表面通过亲水改性形成亲水胶粘过渡层，然后通过聚电解质层层自组装方法或界面聚合法构筑超薄致密功能皮层，亲水胶粘过渡层的引入不仅有助于实现复合膜结构的一体化，而且有效的改善了功能皮层的质量。在此，我们一方面提出了通过纳米纤维垂溶的方法有效的制备了聚乙二醇（PVA）亲水凝胶过渡层；另一方面通过多巴氨化学改性方法在纳米纤维基膜表面自聚形成聚多巴氨亲水胶粘过渡层。进而通过层层组装制备了壳聚糖/海藻酸纳聚电解质脱盐层和通过界面聚合法制备了聚酰氨脱盐皮层。亲水中间过渡层的存在不仅实现基膜和功能皮层间的有效粘合，而且有效的防止了制膜过程中溶液极易向高孔隙率的基膜内部渗漏导致脱盐皮层厚度控制难的问题，有助于实现皮层的超薄致密，实现膜结构的整体优化。对多级结构纳米纤维基复合膜的微观形态结构与脱盐性能进行了系统研究，获得了低压高效脱盐淡化复合滤膜。基于纳米纤维多孔膜的纳米复合膜的设计制备及相关规律研究，将对高分子膜科学与技术的发展具有重要意义，推动了该领域的发展，为进一步研究奠定了基础。

中文关键词： 纳米纤维复合膜;脱盐淡化;高通量;低压;形态结构

英文摘要： In this project, three-tier thin film composite filtration membranes consisting of nanofibrous substrate as supporting layer, a transition middle layer and nonporous ultrathin barrier layer, were fabricated for water desalination. At first, the nanofibrous substrate was hydrophilic modified to form a transition adhesive layer, then a nonporous ultrathin top barrier layer was prepared by electrostatic layer-by layer self-assembling or interfacial polymerization. The introduction of the hydrophilic transition layer improved the integrity of the multilayer structure of the composite membrane, but also was facilitated to prepare the top barrier layer as thin as possible and the thickness easily to be controlled. Here, a facile strategy for fabrication of the hydrophilic PVA hydrogel middle layer by electrospinning combined with solvent treatment was proposed, overcoming the shortcoming of easy penetration of the coating solution into the porous substrate. And a very thin adherent polydopamine was also prepared acting as a transition layer by the self-polymerization of dopamine on the surface of nanofibrous supporting layer. Then series of active barrier layers were subsequently prepared on the adhesive transition layer. A series of Chitosan/alginate polyelectrolyte multilayers acting as the barrier layers were prepared by layer-by layer technique and a series of polyimides barrier layers were also prepared by interfacial polymerization method. The presence of the transition layer could enhance the structural stability of the composite membrane including the integrally skinned structure approach for making the ultrathin barrier layer with high quality to acquire high permeation flux with high rejection. At last, low pressure high flux thin film composite membranes for water desalination based on nanofibrous substrates have been prepared, and the relationship between the structure, morphology and seawater desalination property of the thin film composite membranes have been studied in detail. The coordinated effect of the multilayers and the corresponding membrane separation and penetration mechanism has also been investigated. We believe that the study on design, preparation and related rules for the composite membranes based on nanofibrous substrates possessing high flux with high rejection rate will provide important guidance information for the development of science and technology of polymer membranes.

英文关键词： thin film nanofibrous composite membrane; water desalination; high flux; low pressure; morphology and structure