Xing Weihong

Membranes and membrane reactors: state of the art, challenges, and opportunities

Membranes and membrane reactors are providing approaches to realize high-efficient separation and reaction/separation coupling, thus making increasingly important contributions to address the global issues of energy shortage, environmental pollution, and resources depletion. In this work, we categorize membranes into three main groups, macroporous, microporous, and nonporous membranes, according to their mass transfer and separation mechanisms. We review the latest significant achievements of these membranes, and discuss the bottlenecks and potential breakthoughs of their future development. Furthermore, we make a more detailed survey on the recent progresses in membrane reactors, and conclude this paper with a perspective on the research areas requiring focused attentions of membranes and membrane reactors.

嵌段共聚物模板法制备La掺杂TiO 2 超滤膜

以钛酸四丁酯为Ti源, 氯化镧为La源, 采用嵌段共聚物模板法制备了La掺杂TiO 2 超滤膜。通过动态热机械分析(DMA)、X射线衍射(XRD)、低温氮气吸附脱附和X射线光电子能谱(XPS)等表征方法, 考察了La掺杂对TiO 2 凝胶的机械性能及其材料晶型、孔结构的影响。分析结果表明, La的引入显著提高了TiO 2 凝胶的机械性能,避免了膜层在干燥阶段的开裂现象; 并有效抑制了晶粒增长和晶相转变, 使得锐钛矿相在800℃下仍能保持稳定。同时La的引入也提高了TiO 2 材料的比表面积和孔隙率, 通过实验确定La掺杂量为0.74 g, 此时TiO 2 溶胶的粒径分布最均一, 所得溶胶粒径为10 nm。采用该溶胶制备出的La-TiO 2 超滤膜的孔径为2.3 nm, 而未掺杂时膜的孔径为2.7 nm。