原位成胶抗油污污染自修复水凝胶及其油水分离机理研究

The study on novel oil/water separation materials based on special wettability is of great significance to the separation of oilfield produced liquid, and the improvement of oilfield productivity. However, the separation materials are faced with serious fouling and damage problems during the practical application. To address these issues, developing oil/water separation materials with anti-fouling and intrinsic self-healing properties is of significant research value. In this study, multi-functional hydrogels are prepared through self-assembly of synthetic block copolymers. By controlling the monomer species, ratio and polymer molecular weight, the mechanical strength, sol-gel transition temperature and rate of the prepared hydrogels are adjusted; the synergistic structure-function relationships among different monomers are illuminated. The rheological behaviors, in-situ gelation and self-healing properties of the hydrogels are characterized using a rheometer, while the anti-fouling properties of the hydrogels are studied through Quartz Crystal Microbalance with Dissipation (QCM-D). Oil/water separation experiments are conducted; the separation efficiencies under different temperatures, pH and salt concentrations, oil breakthrough pressure and recyclability of hydrogel-coated mesh to different kinds of oil/water mixtures and emulsions are studied. By micro-nano morphology characterization, wettability study and surface force tests, the oil/water separation mechanisms of hydrogel-coated mesh are unveiled. Finally new methods on the preparation of novel superhydrophilic/underwater superoleophobic oil/water separation materials with antifouling and self-healing properties are established.

基于特殊润湿性的油水分离材料的研究对于高效低耗地分离高含水油藏产出液、提高油田生产效益具有重大意义，然而网膜分离材料在实际应用中面临严重的油污污染及破损问题，针对这一难题，研发具有抗油污污染与本征型自修复性能的油水分离材料具有重要的科研应用价值。本研究通过合成嵌段共聚物自组装制备多功能水凝胶，通过调节单体种类、配比及聚合物分子量调控制备水凝胶的机械强度、相转变温度及速率，阐明各功能性单体间的协同构效规律；借助流变仪定量研究水凝胶的流变性能、原位成胶性能与自修复性能，借助耗散型石英晶体微天平定量研究其抗污染性能；考察水凝胶修饰网膜在不同温度、矿化度、pH下对油水混合物及含油乳液的分离效率、油突破压力与循环利用性能；通过纳微尺度形貌分析、润湿性研究以及表面力测试多角度揭示水凝胶修饰网膜的油水分离机理，建立具有抗污染与自修复性能的超亲水/水下超疏油型油水分离新方法。

高含水采出液的处理是油田开发亟需解决的热点问题。目前采出液的处理主要包括以重力沉降和旋流分离为主的预处理以及外加化学剂或高频电场进行破乳的深度处理，能耗高、分离效率低。基于特殊润湿性的油水分离网膜在实际应用中面临严重的油污污染及微纳粗糙结构磨损影响性能的问题。针对这一难题，本项目提出超亲水/水下超疏油水凝胶薄层修饰网膜的采出液油水分离新方法。采用聚多巴胺（PDA）和功能化亲水聚合物在基底网膜表面原位构筑水凝胶网络，通过薄而稳定的水化层作为油品渗透屏障使膜具有水下超疏油性，从而实现对于油水混合液/乳液的高效低耗选择性分离。.本项目通过可控聚合反应合成一种含有贻贝仿生多酚粘附基团的功能化亲水聚合物，采用PDA与功能化亲水聚合物两步浸涂在基底金属膜和微滤膜表面构筑水凝胶薄层，综合分析膜表面的微观形貌、化学性质以及宏观润湿性，表明水凝胶修饰网膜具有超亲水/水下超疏油性能。探究了网膜对油水混合液/乳液的分离特性，具有高效率、高通量、耐苛刻条件及可重复使用的优势。基于分子间相互作用理论，探明多重聚合物网络构建过程中物理/化学键的形成以及特定环境下聚合物网络结构；通过表面自由能热力学分析超亲水性能产生原理。通过纳米力学实验确定油水分离过程中粘附或排斥作用来源，结合膜微通道简化模型内力学分析阐明油水选择性分离及破乳的作用机制。本项目通过多级网络结构设计，创新提出基底膜表面原位构筑水凝胶薄层制备超亲水分离网膜新方法，对于高效低耗分离高含水采出液具有重要意义。