Treatment of industrial brine using capacitive deionization (CDI) towards zero liquid discharge – challenges and optimization. (15th September 2020)

• Record Type: Journal Article
• Authors: Liu, Enyu; Lee, Lai Yoke; Ong, Say Leong; Ng, How Yong
• Is Part Of: Water research. Volume 183(2020)
• Publication Date: 2020-09-15
• Subjects: Capacitive deionization -- Industrial brine -- Zero liquid discharge -- Total dissolved solids -- Scaling -- Fouling; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2020.116059
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Thermal-based Zero Liquid Discharge (ZLD) process has been used for managing industrial brine. However, conventional thermal ZLD process is very energy intensive. In view of this, pre-concentration techniques have been applied prior to thermal process to reduce energy consumption of ZLD systems. Capacitive Deionization (CDI) is an emerging desalination technique and has yet to be extensively explored for the treatment of industrial brine especially for ZLD applications. High concentration of total dissolved solids (TDS) and high fouling potential of industrial brine are two major challenges in CDI process. This paper reviews the possible factors for optimizing CDI process in industrial brine treatment, namely, cell architectures, strategies in operation and fouling control. Cell architectures of membrane CDI (MCDI) and flow-electrode CDI (CDI) are preferred options for treating industrial brine compared with classic CDI in terms of energy consumption and fouling propensity. There are other operational strategies that could enhance the feasibility of using CDI process for ZLD application. These include reversed voltage desorption, multi-stage operation, brine recirculation and fouling control. Fouling control methods comprise pretreatment, antifouling modification, antiscalant and chemical cleaning. These methods could be integrated to optimize fouling mitigation. In addition to providing insights on feasibility of using CDI to concentrate industrial brines, this review also proposed guidelines for optimizing CDI process applied to treat industrial brines for ZLD applications. Graphical abstract: Width of arrow indicates relative significance of the impact from each aspect. Red lines indicate negative impacts. Dashed lines indicate theory only. Image 1 Highlights: Total dissolved solids and foulants in industrial brines are challenging for CDI process. Possible factors for optimizing CDI process are reviewed for industrial brine treatment. Guidelines of designing CDI process for brine treatment are suggested. Future study required on CDI fouling mechanism and mitigation for ZLD applications.