Environmental Process Modelling Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore.
Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Environ Sci Technol. 2022 Jun 21;56(12):8885-8896. doi: 10.1021/acs.est.2c00982. Epub 2022 Jun 6.
The critical challenges of using electromembrane processes [e.g., electrodialysis and flow-electrode capacitive deionization (FCDI)] to recycle resources (e.g., water, salts, and organic compounds) from wastewater are the fractionation of dissolved ionic matter, the removal/recovery of organic components during desalination, and membrane antifouling. This study realized the simultaneous fractionation, desalination, and dye removal/recovery (FDR) treatment of dye/salt mixtures through a simple but effective approach, that is, using a carbon cloth-modified FCDI (CC-FCDI) unit, in which the carbon cloth layer was attached to the surface of each ion-exchange membrane (IEM). The IEMs and carbon-based flow-electrodes were responsible for the fractionation and desalination of dye and salt ions, while the carbon cloth layers contributed to the active membrane antifouling and dye removal/recovery by the electrosorption mechanism. Attributed to such features, the CC-FCDI unit accomplished the effective FDR treatment of dye/salt mixtures with wide ranges of salt and dye concentrations (5-20 g L NaCl and 200-800 ppm methylene blue) and different dye components (cationic and anionic dyes) under various applied voltages (1.2-3.2 V). Moreover, the active membrane antifouling by virtue of the carbon cloth facilitated the excellent and sustainable FDR performance of CC-FCDI. The removal/recovery of dyes from the carbon cloth strongly depends on the characteristics of dye molecules, the surface properties of the carbon cloth, and the local pH at the IEM/CC interfaces. This study sheds light on the strategies of using multifunctional layer-modified FCDI units to reclaim resources from various high-salinity organic wastewater.
用电膜过程（例如电渗析和流动电极电容去离子（FCDI））从废水中回收资源（例如水、盐和有机化合物）的关键挑战是溶解离子物质的分离、脱盐过程中有机成分的去除/回收以及膜的防污。本研究通过一种简单而有效的方法实现了染料/盐混合物的同时分离、脱盐和染料去除/回收（FDR）处理，即使用碳布修饰的 FCDI（CC-FCDI）单元，其中碳布层附着在每个离子交换膜（IEM）的表面。IEM 和基于碳的流动电极负责分离和脱盐染料和盐离子，而碳布层通过电吸附机制有助于活性膜防污和染料去除/回收。由于这些特点，CC-FCDI 单元在各种施加电压（1.2-3.2 V）下，能够有效处理盐和染料浓度范围广泛（5-20 g L NaCl 和 200-800 ppm 亚甲基蓝）以及不同染料成分（阳离子和阴离子染料）的染料/盐混合物的 FDR 处理。此外，碳布的主动防污功能有利于 CC-FCDI 的出色和可持续的 FDR 性能。染料从碳布上的去除/回收强烈取决于染料分子的特性、碳布的表面性质以及 IEM/CC 界面处的局部 pH 值。本研究为使用多功能层修饰的 FCDI 单元从各种高盐有机废水中回收资源的策略提供了思路。
