Electrokinetic desalination of brackish water and associated challenges in the water and energy nexus

Abstract

This review explores the current state-of-the-art in the removal of ions from water to treat brackish water using electrokinetic technologies, while identifying emerging technologies and potential advances in materials science, process engineering, and system integration. We first provide a definition of the class of electrokinetic desalination methods, and propose measurement and reporting standards to improve technology comparisons. The review focuses on two major types of electrochemical processes: electrodialysis (and electrodeionization) and capacitive deionization. We include hybrid systems that combine battery-based desalination, and capacitive neutralization deionization. Finally, we consider the interconnectivity between desalination and energy, and discuss the balance between energy efficiency, water throughput in the context of large-scale deployment of a desalination plant, and environmental impacts.