集成膜技术深度处理稀土工业氨氮废水过程中膜污染机理研究

Ultrafiltration integrated with reverse osmosis (UF+RO) is an alternative method for the removal of excessive ammonia nitrogen due to its specific characteristics with low energy consumption and high separation performance. However, membrane fouling has been a limitation for its application in rare earth industry. This project is to elucidate the fouling mechanism caused by solutes in wastewater of rare earth industry, on the basis of the interaction in the micro-interfacial process involved with pollutants and membrane surface during integrated membrane process. The behavior and activity of pollutants on membrane surface is investigated under the combination of advanced experimental instrument analysis, computer simulation and membrane performance evaluation system. Through in-depth study of the influences of membrane materials, operating conditions and physical/chemical properties of the solution on the membrane performance, we try to establish a performance evaluation system for the membrane process. The adsorption layer of pollutants on the solid-liquid interface is investigated by the experimental instrument analysis. With DPD simulation, the micro-interface of “membrane-solution” was coarse grained into DPD models, then the interaction parameters between membrane and pollutants and the boundary conditions of the system are adjusted to be validated by experimental results. The results from both experiments and DPD simulations are to further understand the molecular mechanism of membrane fouling. We try to reveal effective ways to control membrane fouling, thus improve the membrane performance and prolong the service life of the membrane. Based on the characteristics of the rare earth industry, we aim to provide solid theoretical and practical evidence for industrial wastewater treatment in Gannan, and promote the popularization and application of membrane technology from this project.

以超滤+反渗透(UF+RO)耦合的膜集成技术具有低能耗、高分离效率且对环境友好等特点，可有效解决稀土开采废水中氨氮浓度过高的问题。但膜污染成为限制膜技术应用于稀土工业废水深度处理的瓶颈。本研究以先进的实验表征测试手段、计算机模拟技术和膜性能评价系统，开展“污染物-膜”微界面上各物质间相互作用的研究，并探索膜污染形成机制及其防治策略。通过研究膜材料、操作条件和溶液物理化学性质等因素对膜性能的影响，建立膜集成工艺综合评价系统；通过对膜分离过程中溶质在膜表面的吸附形态与结构进行表征，结合DPD模拟技术建立“膜-溶液”微界面模型，确立膜表面与污染物分子之间的相互作用参数以及系统的边界条件，模拟污染物在膜表面的动态过程，深入探讨膜污染机理并提出防治措施，提出提高膜效率和延长膜使用寿命的有效途径。通过本研究，结合稀土工业废水特点，为赣南地区工业废水治理提供有力的理论与实践依据，促进膜技术的推广与应用。

本项目以高氨氮稀土冶炼废水为背景，利用膜集成技术深度处理该类废水并研究膜分离过程中无机盐与水分子的传质机制以及有机物小分子导致膜污染的机理，以突破膜污染这一制约膜法水处理技术广泛应用的瓶颈。项目实施过程中，紧密围绕“集成膜工艺综合评价方法”、“膜-污染物相互作用机理表征”以及“膜-溶液系统DPD模型的建立和验证”三个关键科学问题的深入研究，建立了预处理(超滤/电渗析)+反渗透膜集成工艺的性能综合评价系统，实现了高浓度氨氮废水的达标排放；结合溶解-扩散模型和电解质理论、浓差极化理论，初步形成了以活性为基础的新型传质机制模型，为研究水分子和无机盐类分子在膜内的传质过程、膜的渗透性能与选择分离性能提供了新的思路；分析并建立了有机物分子和聚酰胺膜结构的DPD模型及膜污染形成机制相关基础理论，结合实验与模拟结果互相验证，为有效防治膜污染及相关膜材料的开发与应用提供了理论依据和技术参考。在Journal of Membrane Science, Journal of Materials Chemistry A, Desalination, ACS Applied Materials & Interfaces等化工、膜领域顶级期刊上发表SCI论文9篇；申请国际发明专利3项，申请中国发明专利9项并获授权3项。