碳量子点构建新型正渗透膜、驱动溶质及性能研究

Concentrating of industrial wastewater using forward osmosis is low energy consumed and friendly to environment. It has important social and economic benefits due to water purification and useful composition recovery can be accomplished at the same time. However, there are some problems, such as, membrane fouling, internal concentration polarization within the porous sublayer, and the discouraging osmosis pressure and/or concentrating of draw solution during forward osmosis.. To resolve the problem remarked above, firstly, we will improve the anti-fouling performance of the membrane through modifing the surface of the PAA-PEK-C composite membrane using the superhydrophilic and molecular controllable carbon quantum dots. Nextly, we will modify the PEK-C porous sublayer with superhydrophilicity of TiO2/SiO2 nanotube to improve the hydrophilicity of the wall. In addition, we will prepare the desired draw (driving) solutions using the superhydrophilic and molecular controllable carbon quantum dots coated Fe3O4 magnetic nanoparticles as draw solutes. Finally, we will evaluate the performance of the prepared forward osmosis membrane and the draw solutes enhanced through the quantum effect and high hydrophilicity of the carbon quantum dots in concentrating industrial wastewater. . In short, in this project, we will carry out a systematical study on the preparation of desired forward osmosis membrane and draw solutes. The systematical study will be helpful to design and exploit new membrane separation process, meanwhile, to advance other membrane processes with the application of the carbon quantum dots, a promising material.

利用正渗透膜将工业废水浓缩是一个低能耗、环保过程；它使水的净化和有用成分回收同时进行，具有重要的社会和经济效益。然而正渗透膜分离通常会存在膜污染、支撑层孔内存在浓差极化以及驱动液渗透压不理想、不易浓缩等问题。. 解决上述问题，本项目首先利用高亲水性且分子量可控的碳量子点修饰PAA-PEK-C复合膜活性层以提高其抗污染性能；其次，利用超亲水性TiO2/SiO2纳米管调控膜支撑层孔特性，最终构筑高效正渗透复合膜。另外，利用分子量可控的碳量子点包覆磁性Fe3O4纳米颗粒制备高渗透压、易浓缩驱动溶质。通过碳量子点的量子效应和高亲水性，最终构建可用于工业废水浓缩的抗污染、低内浓差极化、驱动溶质易浓缩的正渗透膜分离体系。并研究结构与性能之间的关系。. 本项目的研究成果，将对系统地开发其它的膜分离过程产生积极作用；同时为碳量子点在其它膜过程的应用提供借鉴。

利用正渗透膜将工业废水浓缩是一个低能耗、环保过程；它使水的净化和有用成分回收同时进行，具有重要的社会和经济效益。然而正渗透膜分离通常会存在膜污染、支撑层孔内存在浓差极化以及驱动液渗透压不理想、不易浓缩等问题。.为解决上述问题，本项目首先利用超亲水性TiO2/SiO2纳米管调控酚酞侧基聚芳醚酮（PEK-C）膜多孔支撑层孔特性，然后在PEK-C表面通过界面聚合形成致密且薄的聚酰胺（PA）活性层，最后利用高亲水性的碳量子点和聚乙烯亚胺在PEK-C/PA表面自组装修饰构建了高效正渗透复合膜SiO2@TiO2/[PEI/CQD]2PEI。同时也利用磺化改性的酚酞侧基聚芳醚酮 (SPEK-C) 作为主要成膜的活性层，以不同目数尼龙布作为支撑层，采用涂布的方式制备了SPEK-C/尼龙布高效复合正渗透膜。 其次，利用碳量子点包覆磁性Fe3O4纳米颗粒制备高渗透压、易浓缩驱动溶质。最后研究了制膜条件、操作条件等对正渗透膜性能的影响。.实验结果表明在PEK-C支撑层中添加一定量的TiO2/SiO2纳米管能显著提高正渗透膜的性能。进行自组装修饰PEK-C/PA复合膜制备SiO2@TiO2/[PEI/CQD]2PEI复合正渗透膜时候，自组装碳量子点溶液的浓度、自组装的层数等制备条件对正渗透膜的性能影响较大。SPEK-C的磺化度、支撑层尼龙布的目数等对SPEK-C/尼龙布复合正渗透膜的性能有显著的影响。以甲基蓝、牛血清蛋白以及聚乙二醇溶液测试SiO2@TiO2/[PEI/CQD]2PEI、SPEK-C/尼龙布的正渗透性能，结果显示所制备的膜具有较好的抗污染正渗透性能。以碳量子点包覆磁性Fe3O4纳米颗粒制备的驱动溶质具有渗透压高且具有较好重复利用性能。.本项目的研究成果，将对膜的制备及应用提供借鉴。