Bio-Based Carbon Materials for Capacitive Deionization CDI Desalination Processes

Water desalination has become a reliable tool to meet the increasing water demand in areas with a shortage of freshwater resources. Thermal and membrane desalination processes have been dominating desalination for decades, however, it has the demerits of extensive energy demand and harsh environmental impact. Accordingly, the search for more energy-efficient and environmentally friendly desalination processes has been an active area for research and development in recent years. Among emerging desalination processes, capacitive deionization CDI has evolved as a very promising desalination technology at lower energy consumption. However, the core performance and cost element of CDI is the high capacitance electrode material. Carbon-based electrode materials are very efficient in CDI applications. In this article, we highlight and discuss bio-based materials, mainly carbon derived or originated from biomaterial as electrode materials. The article explored and discussed has shown that bio-based materials are efficient for CDI applications with comparable performance to conventional carbon-based materials. This in turn makes the CDI process a greener process, as such bio-based materials can be derived from many agricultural residues and wastes. This additionally, has the dual benefits of positive waste management and potential cost reduction of desalination. The bio-based carbon materials have shown extremely high specific surface area up to 3320 m²/g, porosity up to 2.46 cm³/g, specific capacitance up to 400 F/g, specific electrosorption capacity of 23.3 mg/g.