Evaluation of the Chemical Drivers behind Membrane Integrity Loss in Halide-Impaired Waters during Chemical Disinfection to Advance Optimal Membrane Structural Design

近年来，由于淡水短缺增加了对海水淡化和水回用的需求，膜过滤在处理盐损伤水域中的作用变得越来越普遍。受损水的消毒和脱盐过程受到水成分极端变化的挑战。该项目提出了一个基础研究框架，它将使未来在这种受损水条件下的水处理策略的知情设计成为可能，特别是在延长膜寿命方面。本研究项目的中心目标是整合聚合物和水相化学的控制化学原理，以推进膜工程应用的科学基础。该项目有以下计划成果：(1)预测在卤化物受损的水中接触消毒剂后膜的降解，以及(2)对抵抗这些影响的新型膜表面的知情设计。为了实现这些结果，将使用固体膜材料和模型化合物作为其化学类似物来评估化学动力学，副产物形成以及膜表面的形态和化学变化。模型原料水将含有各种卤化物盐（如氯化物、溴化物和碘化物离子）以及化学消毒剂（如游离氯和氯胺）的混合物，以便测量综合化学效应。实验计划将确定水质（即盐度、温度）和操作条件（氧化剂剂量）的影响。考虑到在膜过滤过程中观察到的浓度极化效应可能会放大这些参数的影响，这一点尤其重要。最后，该项目将为新型膜表面的设计提供信息，通过化学和结构修改来减少膜的破坏。这种膜材料的发展代表了一种明显的技术进步，可以为处理受损水域的设施节省大量的能源和经济。总的来说，该项目将为海水淡化行业和水回收公司提供宝贵的见解，了解在纳滤和反渗透处理之前应用各种消毒策略时，高盐（卤化物）含量的受损水将如何影响膜性能。

160588ShahIn recent years, the role of membrane filtration to treat salt-impaired waters has become more commonplace as freshwater shortages have increased the demand for seawater desalination and water reuse. The process of disinfection and desalination of impaired waters is challenged by the extreme variation in water composition. This project presents a fundamental research framework which will enable future informed design of water treatment strategies under such impaired water conditions, specifically with respect to prolonging membrane lifetime. The central aim of this research project is to integrate governing chemical principles of polymers and aqueous phase chemistry to advance the scientific foundation in membrane engineering applications. The project has the following planned outcomes: (1) prediction of membrane degradation following disinfectant exposure in halide-impaired waters, and, (2) informed design of novel membrane surfaces that are resistant to these effects. To achieve these outcomes, solid membrane materials and model compounds that serve as their chemical analogs will be used to assess chemical kinetics, by-product formation, and morphological and chemical alterations of the membrane surface. Model feedstock waters will contain various mixtures of halide salts (e.g. chloride, bromide, and iodide ions) as well as chemical disinfectants (e.g. free chlorine and chloramines) in order to measure combined chemical effects. The experimental program will identify the effects of water quality (i.e. salinity, temperature) and operational conditions (oxidant dose). This is especially important given that concentration polarization effects observed during membrane filtration can potentially magnify the impact of such parameters. Finally, this project will inform the design of novel membrane surfaces that minimize membrane failure through chemical and structural modifications. The development of such membrane materials would represent a clear technological advancement which could result in significant energy and economic savings to facilities treating impaired waters. Overall, this project will provide desalination industries and water reclamation utilities valuable insight on how impaired waters with high salt (halide) content will effect membrane performance when various disinfection strategies are applied prior to nanofiltration and reverse osmosis treatment.