多维空间改性的PBI材料和PBI-FO膜的研究及其在污水处理中的应用

As forward osmosis (FO) is an emerging "green" membrane technology to solve the problems of water pollution, the objective of this project is to study the application of FO processes in industrial wastewater treatment. Industrial wastewater has the features of complicated composition, high concentration and having a broad pH range which require the FO membrane to have a good chemical stability and corrosion resistance. Polybenzimidazole (PBI) membrane with characteristics of good chemical stability and corrosion resistance can be used in wastewater treatment. However, PBI material has a poor solubility and the casting solution is not easy to prepare. Furthermore, the existing PBI membranes are easy to brittle, have the problem of delamination; the water flux and salt rejection are both very low in the FO process. Therefore in this project, we propose to synthesize novel PBI material with properties of good hydrophility, high density and good solubility through chemical grafting, so that the novel dual layer hollow fiber FO membranes fabricated from the novel PBI material will have good mechanical properties and no delamination problem, and have remarkable improvements in both water flux and salt rejection. The novel FO membranes will be applied to FO processes in treating industrial wastewater containing heave metals or anionic species. Meanwhile, investigations of the membrane fouling, membrane cleaning methods and the regeneration performance of the FO membrane will also be conducted to optimize the FO wastewater treatment process and re-use the FO membrane. The modification of PBI material, the fabrication of novel PBI-FO membrane and the study of FO processes in wastewater treatment in this project will provide new technology and ideas for the development and application of the FO membrane technology.

基于正渗透（FO）是一种新兴的“绿色”解决水污染问题的膜技术，本项目拟研究FO过程在工业污水处理中的应用。工业污水“成分复杂、酸碱度范围宽”，要求FO膜化学稳定性好、耐腐蚀。聚苯并咪唑（PBI）膜“性能稳定、耐腐蚀”，可以用于污水处理。但PBI材料溶解度小，铸膜液不易制备；且现有的PBI膜易脆、易分层、FO过程水通量低、对盐截留率不高。本项目拟通过化学接枝改性PBI材料，提高其亲水性、致密度和溶解性，使新制备的双层PBI-FO中空纤维膜机械性能好、不易分层、水通量和对盐截留率都显著提高；并应用于FO膜工艺对含重金属离子或阴离子的污水进行处理；探索膜污染状况、膜清洗方法和膜再生性能，以优化FO污水处理体系，使膜可以循环利用。本项目对PBI材料的改性、PBI-FO膜的制备及FO膜工艺污水处理的研究将为FO膜技术的发展和应用提供新技术和新思路。

压力驱动的膜工艺在水处理中常有严重的膜污染，而正渗透（FO）因利用膜两侧的渗透压差驱动水从原料液进入汲取液，无需外加压力，膜污染低，水回收率高，并能以高的截留率滤除各类污染物。因此FO满足当前对新兴技术 “高效节能环保” 的要求。但使用理想的FO膜和汲取液才能发挥FO工艺的优势，这是当前FO技术的挑战所在。因此，本项目着重于新型汲取液及FO膜的设计合成及应用研究。根据改性材料离子化程度的不同，设计合成了哌嗪类两性离子、咪唑类离子液体、 磷酸材料、磺化材料等新型材料；通过高效的酰胺化反应或者金属离子桥连对聚酰胺FO膜改性，制得系列新型FO半透膜；同时根据回收方式的不同，设计合成了有机酸-金属配合物、哌嗪类磺化材料、咪唑类离子液体、金刚胺类笼型超分子材料等作为汲取液。我们研究了新制备的FO 膜及汲取液在水处理，如海水淡化、油水分离、染料废水和重金属废水（如含Cu2+、Zn2+、As3+/5+）处理，痕量有机物去除以及蛋白质回收中的应用。本项目设计合成的FO膜较聚酰胺基膜选择性大大提升，水回收率提高（> 50%），且其耐污染性能、耐氯性能和再生性能大幅提升；同时新制备的汲取液较常见的NaCl、MgCl2、NH4HCO3等汲取液反向通量几乎为零，降低了对原料液的污染；且可以通过pH调节等智能方式回收，使FO后处理过程更经济实用。

内容获取失败，请点击重试