Development in desalination and wastewater treatment: state of the art challenges, role of solar energy, and recommendations

Abstract Water purification is crucial to ensure the availability of safe and clean water for protecting human health and helping in a sustainable environment. This review explicitly provides an overview of the major developments related to seawater desalination and wastewater treatments as a unit. Anticipating these traditional independent facilities will operate together in the future mainly for economic benefits. The advances in seawater desalination are primarily focused on the production of membranes using different types of nanoparticles (CeO2, UiO-66, CS-NPs) and carboxylated multi-walled CNTs into a polyamide that provides high salt rejection (as high as 90%) with excellent selectivity and permeability. Further, the use of nanoporous reduced graphene oxide (rGO) membranes provided 27.7–62.6% desalination rates and up to 96.8% salt rejection, along with protection against membrane fouling. Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) showed excellent rejection of divalent ions during desalination. It is anticipated that the use of solar energy for membrane and thermal desalination may be promising since it reduces the reliance on fossil energy and significantly minimizes greenhouse gas emissions (up to 94%). Solar energy can integrate with the reverse osmosis (RO) process bearing the cost of energy-intensive compressors, making the RO economically attractive.