Water Challenges in South Asian Countries: A Focused Review on Emerging Nanomaterials and Technological Processes in Wastewater Treatment

Abstract

South Asia, the world’s most populated region, is facing many environmental and healthcare challenges due to poor freshwater management/wastewater treatment. Most South Asian (SA) countries, such as India, Pakistan, Sri Lanka, and Bangladesh, are suffering from water pollution issues generated due to domestic and industrial effluents containing heavy/toxic ions, textile dyes, pharmaceuticals, bacteria/viruses inorganic/organic pollutants, etc. To overcome these challenges, extensive research is being carried out with an emphasis on technological development to maintain water sustainability. The present review discusses water pollution as well as various challenges in SA countries along with solutions through scientific research carried out by developing nanomaterials and technological wastewater treatment processes, i.e., photocatalytic/adsorptive removal, disinfection, tracing/sensing, etc. Particularly, syntheses of TiO2 nanoparticles and graphene oxide (GO)-based nanomaterials which were found to be most extensively investigated in the SA region have been discussed with emphasis on their multifunctional applications using various water treatment processes, mechanisms, and synergetic effects. Eventually, various challenging issues and solution opportunities are discussed for future development to maintain water sustainability in SA countries.