Electrochemical Ion Exchange Regeneration (ELIXR) and Rapid Electrochemical Crystallization Softening (RECS) for Chemical and Waste-Free Water Softening and Reclamation

1235596(法雷尔)。开展这项研究是为了直接回应人们对公共饮用水供应中盐分积累的日益关注以及社区日益需要依赖水再利用的问题。这项研究将测试两种新的电化学工艺去除饮用水和废水中的硬度离子、二氧化硅和溶解有机物的可行性。ELIXR工艺利用电化学池产生酸和碱，用于离子交换(IX)介质的再生。酸和碱是利用水中存在的离子产生的，因此不需要使用任何化学物质。RECS过程是对球团软化的电化学强化，在该过程中，电化学池取代了用于调节pH的酸和碱。RECS工艺也可用于去除溶解的二氧化硅和有机物，作为反渗透(RO)的前处理，或作为反渗透精矿的后处理工艺。ELIXR和RECS工艺的结合可以消除在IX再生过程中通常产生的盐水溶液的生产。因此，除了水的软化，ELIXR和RECS工艺还可以用于从水回收操作中产生零液体排放。这项研究的目的是测试ELIXR和RECS过程的概念证明。实现这一目标需要下列智力贡献：1)对两种新的水处理技术进行概念验证；2)开发在IX再生剂溶液中浓缩离子的方法；3)确定离子浓度和形态对生产酸再生剂溶液所需能量的影响；4)确定电流密度、氯化物和硫酸盐浓度对次氯酸盐和过硫酸盐生产的影响；5)确定块碳过滤器去除次氯酸盐的有效性；6)确定过硫酸盐对常规离子交换介质和基于聚丙烯的离子交换纤维的影响；7)确定RECs去除Elxr和RO浓缩物中的硬度离子、二氧化硅和溶解有机物的有效性；8)测定直接阳极氧化和阳极产生的氧化剂种类对RO精矿中溶解有机物和生物难降解污染物的破坏效果。这项研究最广泛的影响是，它解决了该国干旱地区饮用水的两个最大问题，即：1)地下水供应日益盐碱化；2)与反渗透和水回收活动有关的预处理和浓缩处置问题。ELIXR和RECS工艺将对水回用处理产生直接影响，因为它们能够去除水中的离子、溶解固体和有机物，而不需要添加化学物质或产生浓缩液。此外，ELIXR和RECS工艺将缓解与运输和储存大量危险化学品相关的污染和自然资源需求，减少传统处理方法的足迹，并降低净水成本。教育和多样性计划侧重于从代表性不足的群体中招收学生，并将研究成果纳入首席调查员目前正在管理的ENGR 102-高中课程的能源、水和环境部分。

1235596 (Farrell). This research is being pursued in direct response to the growing concern of salt accumulation in public drinking water supplies and the increasing need for communities to rely on water reuse. The research will test the feasibility of two novel electrochemical processes for removing hardness ions, silica and dissolved organic matter from potable and waste waters. The ELIXR process utilizes an electrochemical cell for producing acids and bases for the regeneration of ion exchange (IX) media. The acids and bases are produced using the ions present in the water, and thereby does not require the use of any chemicals. The RECS process is an electrochemical enhancement of pellet softening, in which an electrochemical cell replaces the acids and bases used for pH adjustment. The RECS process can also be used for removing dissolved silica and organic matter as a pretreatment for reverse osmosis (RO), or as a posttreatment process on RO concentrates. Combination of the ELIXR and RECS processes can eliminate the production of brine solutions that are normally generated during IX regeneration. Thus, in addition to water softening, the ELIXR and RECS processes can be used to produce zero liquid discharge from water reclamation operations. The objectives of this research are to test the proofs of concept for the ELIXR and RECS processes. Achieving this objective will require the following intellectual contributions: 1) proof of concept validation for two new water treatment technologies; 2) development of methods to concentrate ions in IX regenerant solutions; 3) determination of ionic concentration and speciation effects on energy requirements for producing acid regenerant solutions; 4) determination of current density, chloride and sulfate concentration effects on the production hypochlorite and persulfate; 5) determination of the effectiveness of block carbon filters on hypochlorite removal; 6) determination of persulfate effects on conventional ion exchange media and on polypropylene based ion exchange fibers; 7) determination of the effectiveness of RECS for removing hardness ions, silica and dissolved organic matter from ELIXR and RO concentrates; and 8) determination of the effectiveness of direct anodic oxidation and anodically produced oxidant species for destroying dissolved organic matter and biologically recalcitrant contaminants in RO concentrates. The broadest impacts of this research are that it addresses the two biggest issues with potable water in arid regions of the country, namely: 1) the increasing salinification of the groundwater supplies; and 2) the pretreatment and concentrate disposal issues associated with RO and water reclamation activities. The ELIXR and RECS processes will have a direct impact on water reuse processing as they are able to remove ions, dissolved solids and organic matter from water without chemical addition or production of concentrate streams. In addition, the ELIXR and RECS processes will alleviate the pollution and natural resource requirements associated with the transport and storage of large quantities of hazardous chemicals, reduce the footprint of traditional treatment methods, and reduce the costs of purifying water. An education and diversity plan focuses on recruiting students from under-represented groups and integration of research results into the energy, water and the environment component of the ENGR 102-High School course that the principal investigator is currently managing.