Non-Isothermal Donnan-Dialysis: a novel method beyond iso-thermal Water pre-Treatment paradigm for Energy Reduction in desalination

海水淡化技术能够从海洋或其他咸水来源(如地下水和工业废水)中收集大量水。然而，在许多地区，海水淡化处理水的能源强度(EI)越来越受到环境、经济和社会的关注。降低海水淡化厂能耗的一个重要途径是利用大量的余热或低品位热能进行海水淡化厂的前处理。海水淡化的另一个挑战是二价阳离子物种(如钙、镁)对膜的污染和结垢，这需要进行化学投加和预处理，并限制回收水的比例。一些现有的前处理技术采用料液和浓缩液之间的浓度梯度(Donnan-透析)或与离子交换树脂直接离子交换(IEX)。虽然Donnan透析(D2)是一种经济、简单、节能的工艺，但由于其动力学缓慢，并未在工业上得到广泛应用。本文提出了一种非等温D2加速D2动力学的新方法，该方法超越了NID2WATER(NID2WATER)等温水处理方法，通过回收废热作为额外的驱动力。这位研究员将首先开发一个纳米流控芯片，然后开发一个带有离子选择膜的D2堆，分别从根本上和实践上研究NID2。然后，他将进行理论研究，对实验数据进行严格的解释。该项目不仅将为回收海水淡化厂对海洋环境有害的废热提供解决方案，还将通过带电薄膜加强我们对热渗透的理解。预计实验和理论研究将有助于海水淡化在满足世界粮食和水需求以及从海水淡化中回收有价值金属方面的应用。

Desalination technology is able to harvest abundant water from the sea or other saline sources such as groundwater and industrial effluents. However, the energy-intensity (EI) of water treatment by desalination is an increasing environmental, economical, and societal concern in many regions. An important way to reduce the energy intensity is to employ large resources of waste heat or lowgrade heat for pretreatment in desalination plants. Another challenge in desalination is the fouling and scaling of membranes by divalent cationic species (e.g. Ca2+, Mg2+) which necessitates chemical dosing and pretreatment and limits the fraction of water recovered. Some existing pretreatment technologies employ the concentration gradient between a feed and concentrate solution(Donnan-dialysis) or direct ion-exchange with ion exchange resins (IEX). Although Donnan-Dialysis (D2) is an economical, simple technological, and energy-saving process, it is not applied widely in industry because of its slow kinetics. Here, it is proposed to accelerate the D2 kinetics by a Non-Isothermal D2 as a novel method beyond iso-thermal WATer pre-treatment for Energy Reductionin desalination (NID2WATER) via recycling the waste heat as an additional driving force. The Fellow will, firstly, develop a nanofluidic chip and then a D2 stack with ion-selective membranes to investigate the NID2 fundamentally and practically, respectively. Then, he will perform a theoretical study to interpret rigorously the experimental data. The project will not only provide a solution for recycling the waste heat from desalination plants that is harmful to the marine environment but also enhance our understanding of thermoosmosis through electrically charged membranes. It is expected that the experimental and theoretical study will contribute to the applications of desalination in meeting world food and water demand and in recovering valuable metals from desalination brines.