Cranfield Water Science Institute, Cranfield University, Building 52a, Cranfield MK43 0AL, UK.
PWN Technologies R&D, Dijkweg 1, 1619 HA P.O. Box 66, Andijk 1619 ZH, The Netherlands.
J Hazard Mater. 2022 Jun 5;431:128530. doi: 10.1016/j.jhazmat.2022.128530. Epub 2022 Feb 19.
Ion Exchange (IEX) applications for drinking water can be limited due to high volumes of brine, brine waste and treated water corrosivity. Reusing the resin by operating at reduced regeneration frequency can overcome this. However, assessing changes on the resin loading over reuse cycles is complex because multiple presaturant ions participate in the exchange and existing models only account for the exchange with one presaturant ion. This study developed a theoretical multicomponent model for the determination of IEX equilibria when the resin loading increases due to reuse. The model suggested that both electrostatic interactions and admicelle formation were the separation mechanisms. The model revealed that under reduced regeneration frequencies, brine use and waste generation can be reduced by more than 90%, where the bicarbonate-form resin offered the potential for lower corrosivity. However, changes in resin loading after 5 reuse cycles showed that the risk of corrosion increased. For the tested source water, reusing the bicarbonate-form resin every 5 cycles would achieve the most sustainable option with 41% NOM removal and 79% brine and waste reduction. Under these conditions, almost 100% of exchange capacity is recovered after regeneration.
离子交换 (IEX) 技术可用于饮用水处理，但由于盐水体积大、盐水废物和处理水腐蚀性强，其应用受到限制。通过降低再生频率来重复使用树脂可以克服这些问题。然而，评估树脂在重复使用周期中的负载变化非常复杂，因为多种预饱和离子参与交换，而现有的模型仅考虑与一种预饱和离子的交换。本研究开发了一种理论多组分模型，用于确定由于重复使用导致树脂负载增加时的 IEX 平衡。该模型表明，静电相互作用和吸附胶束形成都是分离机制。该模型表明，在降低再生频率的情况下，盐水的使用和废物的产生可以减少 90%以上，其中碳酸氢盐形式的树脂具有较低腐蚀性的潜力。然而，重复使用 5 次后的树脂负载变化表明，腐蚀风险增加了。对于测试的水源，每 5 个周期重复使用碳酸氢盐形式的树脂将是最可持续的选择，可去除 41%的 NOM，减少 79%的盐水和废物。在这些条件下，再生后几乎可以回收 100%的交换容量。
