水中溶解性有机物与离子共存体系中超滤膜污染微观作用机制研究

This project mainly focus on the ultrafiltration membrane fouling in the coexistent system of dissolved organic matters (DOM) and inorganic ions. Aimed at unraveling the influence mechanism of ions on membrane fouling from micro-force, and providing theoretical for using inorganic ions to mitigate membrane fouling. Atomic force microscopy (AFM) will be used in conjunction with colloidal probes, to establish the measurement technique of the interaction forces between membrane and DOM and among the DOM themselves in the coexistent system of DOM and inorganic ions. The variation characteristics of the interaction forces between membrane and DOM and among the DOM themselves in the coexistent system with the ionic conditions will be investigated, for getting the ionic conditions that could enhancement and mitigate the membrane fouling micro forces in the coexistent system. Combined this analysis with corresponding fouling experiments and the adsorption behavior of BSA on the UF membrane surface, to unravel the influence mechanism of ions on membrane fouling micro forces. Furthermore, for better understanding the mitigation mechanism of inorganic ion on membrane fouling micro forces, the role of single factor force (such as electrostatic force, hydration force, hydrogen bond force) in the process of mitigating membrane fouling and the mitigation ability will be investigated, at the ionic condition that could mitigate membrane fouling micro forces. Based on above results, propose the technical strategies for using inorganic ions to control membrane fouling micro forces. The ultimate goal is to provide theoretical guidance for the prevention/control and mitigation of UF membrane fouling during wastewater treatment.

本课题针对污水超滤处理过程中，溶解性有机物与离子共存体系中超滤膜污染问题，旨在从微观作用力角度解析离子对膜污染的影响机制，探讨利用内源无机离子减缓膜污染强度的方法。拟采用原子力显微镜结合胶体探针，建立有机物与离子共存体系中膜污染微观作用力测试技术。定量考察超滤膜-有机物及有机物-有机物间相互作用力随无机离子的变化特征，获得增强及削弱共混体系中膜污染微观作用力的离子条件，结合膜污染试验及有机物在膜面的吸附累积行为，探明无机离子对超滤膜有机物污染微观作用力的影响机制。针对削弱膜污染微观作用力的离子条件，解析静电作用力、水合排斥力、氢键力等单因素作用力在弱化膜污染过程中的作用行为，揭示无机离子对膜污染微观作用力的弱化机制及弱化能力的关键控制因素。提出利用无机离子调控膜污染微观作用力相对大小的技术方法，为共存体系中超滤膜污染的防控提供理论指导。

超滤技术被广泛地应用于污水处理与资源化领域，水中大量存在溶解性有机物引起的膜污染问题一直是限制超滤技术推广应用的主要屏障，而无机阳离子是影响膜污染速率及污染幅度的关键因素。本项目从微观层面出发，建立了不同离子条件下有机物-膜及有机物-有机物间微观作用力测试技术。基于微观作用力测试技术，重点考察了典型腐殖类及蛋白类有机物与二价Ca2+、Mg2+及一价Na+、K+等离子共存水质条件下，溶解性有机污染物在超滤膜面的吸附累积过程及吸附层结构特征，结合膜-有机物及有机物-有机物之间的相互作用力特征，解析了超滤过程静电作用力、氢键及水合力等物化作用力随无机离子的变化规律，进而阐明了典型阳离子对溶解性有机物膜污染行为的影响机制。同时，发现了超滤过程水合排斥力的触发机理及其定向控制理念，为实际运行过程中超滤膜污染的减缓提供方案。