辐射法制备超薄无支撑石墨烯基正渗透滤膜及其性能研究

Lamellar graphene oxide (LGO) membrane is a promising novel membrane material because of its high hydrophilicity, excellent water permeability and solute rejection selectivity. Our previous work confirms that free-standing LGO membrane could obviously attenuate the internal concentration polarization effect during forward osmosis (FO) process, and improve the membrane separation efficiency, which is deemed as the ideal candidate of high-performance FO membrane. However, the poor structure stability and small-scale preparation are the critical issues must resolved of LGO membrane research and application. In the subject, we plan to use GO liquid crystal and cross-linker containing aromatic group to obtain stable and plastic complex liquid crystal, and then prepare ultra-thin free-standing cross-linked LGO composite membrane via blade-coating and radiation-crosslinking. This route is expected to enhance structure stability and make scale-up preparation of LGO membrane. Herein, three issues will be investigated mainly, including the formation of complex liquid crystal and lamellar membrane, reaction between GO sheets and cross-linker induced by radiation, and structure stability and membrane performance of the ultra-thin free-standing cross-linked LGO composite membrane. The systematic investigations of the preparation and performance of ultra-thin free-standing cross-linked LGO composite membrane, would provide new method and strategy for the research of novel FO membrane materials, and promote the application of radiation technique to graphene-based novel materials research.

层状排列氧化石墨烯（LGO）膜具有很好的亲水性，极高的水渗透能力和溶质截留选择性，是制备新型滤膜的潜在材料。申请人前期研究证明，无支撑LGO膜可有效减弱正渗透（FO）过程的内浓差极化效应，提高膜分离效率，有望成为理想的FO滤膜材料。然而，结构稳定性较差、批量化制备困难等是LGO膜研究与应用必须解决的关键问题。本项目拟利用GO的液晶特性及π-π相互作用，将GO与含芳基的乙烯基交联剂复合得到稳定且具有塑性的复合液晶流体，再经刮涂成膜与辐照技术制备具有较大面积的超薄无支撑交联LGO膜，以增强其结构稳定性并实现批量化制备。本项目拟着重研究复合液晶的形成及成膜规律、辐照诱发GO片层与交联剂反应的规律、以及所得超薄无支撑交联LGO膜的结构稳定性和膜性能等。本项目对超薄无支撑交联LGO膜的制备与性能的系统研究，有望为新型FO滤膜材料设计与制备提供新思路和新方法，促进辐照技术在石墨烯基新材料研究的应用。

本项目执行期间，项目组根据项目书计划和研究过程的新发现，主要开展了以下四个方面的研究工作：首先是GO复合液晶体系的构建及其成膜行为的研究。主要包括GO浓度、高分子浓度等对流体流延性的影响；成膜条件对GO膜微观形态和膜性能的影响等工作。还研究了GO与咪唑类离子液体之间的相互作用对构建稳定的层状GO复合膜的作用机制及对膜渗透的影响效应。第二，电子束辐照交联增强GO膜稳定性及其渗透效应研究。主要包括利用辐照条件对GO膜层间通道尺寸和水中稳定性的调控；辐照引起石墨烯基片物化结构的变化；探讨所得的增强GO膜的渗透性能及其在酸废水处理的应用等工作。第三，GO复合流体的电子束辐照效应及其成膜行为研究。主要包括GO片层在辐照下的结构修饰与演变行为以及辐照条件对成膜结构与渗透性能影响等，并探讨了不同尺寸的金属离子在所得GO膜中的渗透行为及其回收废酸等工作。第四，其他相关工作包括纳米碳管辐照改性及其构建油水分离膜的研究，辐射法制备高分散性聚吡咯纳米颗粒的研究和辐照交联法改性PVDF膜及其油水分离研究等工作。上述工作都取得了较好的研究成果，为辐射化学用于功能石墨烯及高分子材料的制备、改性及性能研究等方面提供了理论指导和实验方法。