氧化石墨烯膜表面官能团原位调谐与膜污染控制机制研究

Membrane filtration technology is an important technology for advanced treatment and reuse of wastewater. However, membrane fouling limits the further application of membrane filtration technology. Graphene oxide (GO) membrane filtration technology are believed to be a new generation of membrane filtration technology. However, the molecular mechanisms of GO membrane fouling formation and related studies of in situ control are not deep enough. The applicant found in previous research that Inducing trace hydroxyl radicals on the surface of the membrane can cause membrane fouling to disappear. But the molecular mechanism in this process, the stability and universality of the method have not been studied. The quantum mechanical methods simulation, nuclear magnetic resonance, X-ray photoelectron spectroscopy, atomic force microscopy, membrane pollution control experiments, etc. are used to from three-stage analysis. These are the perspective of microscopic molecular mechanisms, mesoscopic mechanical analysis, and changes in macroscopic membrane fouling. The aims of the study are the mechanism that causes GO membrane fouling and the reason of membrane fouling to disappear after surface functional groups tuning by trace of hydroxyl radical. At the same time, by hydroxyl radicals in-situ produce and the threshold study to achieved the process optimism. Finally, establish a membrane fouling in-situ control mode and construct a near-zero pollution biochemical treatment / GO membrane filtration coupling technology. This research is expected to provide solid theoretical support for the application of GO membranes. And provide new ideas for the advanced treatment and reuse of sewage.

膜过滤是污水深度净化及回用中的重要技术，但膜污染问题限制了其进一步推广应用。氧化石墨烯（graphene oxide, GO）膜过滤技术被认为有潜力成为新一代膜过滤技术。然而，GO膜污染形成的分子机制及原位控制相关研究不够深入。申请者在之前的研究中发现了膜面诱导产生微量羟基自由基导致膜污染基本消失的现象。但这背后的分子机制，方法的普适性等问题尚不明晰。本课题通过第一性原理的结构与动力学理论模拟，核磁共振，X射线光电子能谱，原子力显微镜，膜污染实验等手段，从微观分子机制，介观力学测试及宏观膜污染程度变化三个层次解析膜污染形成及微量羟基自由基对膜表面官能团调谐导致膜污染消失的机制。同时，通过羟基自由基原位产生途径优选、产生量控制等方面的研究实现过程优化。最终，建立膜污染原位控制的模式并构建生化处理/GO膜过滤耦合技术。本课题可为GO膜的应用提供坚实的理论支撑，为污水深度处理与回用提供新的思路。

工业水处理特别是高水处理过程中，有机物与无机盐的定向分离深度净化是工业废水处理与资源化的重要环节。然而，传统有机膜在相关应用中存在耐溶剂能力不足，有机物及无机盐筛分能力有限，高含盐含有机物的浓水处理处置困难等问题。本项目面向污水深度净化回用中有机污染物的去除需求与膜污染控制问题，开展了定向分离膜的制备，截留有机物的原位催化去除与膜污染控制等相关工作。（1）通过羧化碳纳米管（CCNT）插层的还原氧化石墨烯（RGO）复合电芬顿膜（RGO-CCNT-Fe）制备及性能；（2）针对催化膜金属及流失的问题，通过调整RGO和掺氮碳纳米管（N-CNT）的比例制备了新型非金属电芬顿催化膜有效实现了污水定向分离深度净化与膜污染控制；（3）将羟基化碳纳米管作为“纳米楔”构建稳定的三维纳米流道并打破氧化石墨烯膜的通量与截留率无法同步提升的“跷跷板”效应，研究了制膜参数如GO/CNTs比例、CNTs长度、直径官能团种类对膜分离性能的影响。研究发现,掺入10%单壁长碳纳米管后膜的纯水通量提高2倍以上，在保持对有机物的高截留率的同时极大降低了对于无机盐的截留率，同时有效控制了膜污染问题。相关成果有望应用于工业废水处理中膜过滤过程对有机物无机盐的定向分离与深度净化过程中。. 本项目执行期间共在Environ. Sci. Technol.、J. Membr. Sci.等本领域国际权威期刊上发表文章8篇，其中SCI收录8篇，申请国家发明专利6项，授权3项，培养硕士研究生4名，完成了项目目标。