Water is obligatory for sustaining life on Earth. About 71% of the Earth’s surface is covered in water. However, only one percent of the total water is drinkable. The presence of contaminants in wastewater, surface water, groundwater, and drinking water is a serious threat to human and environmental health. Their toxic effects and resistance towards conventional water treatment methods have compelled the scientific community to search for an environmentally friendly method that could efficiently degrade toxic contaminants. In this regard, visible light active photocatalysts have proved to be efficient in eliminating a wide variety of water toxins. A plethora of research activities have been carried out and significant amounts of funds are spent on the monitoring and removal of water contaminants, but relatively little attention has been paid to the degradation of persistent water pollutants. In this regard, nanoparticles of doped ZnO are preferred options owing to their low recombination rate and excellent photocatalytic and antimicrobial activity under irradiation of solar light. The current article presents the roles of these nanomaterials for wastewater treatment from pollutants of emerging concern.

Novel water purification technologies are emerging to satisfy the requirement of clean drinking water for human life. The development of long-term water treatment systems is a serious concern. In this regard, nanotechnology holds enormous promise for improving the effectiveness and efficiency of polluted water remediation. The goal of this work was to create a simple and effective water purification system that used cost-effective, durable, and environmentally friendly novel materials. Green nanoparticle synthesis has emerged as a result of recent advancements in environmentally friendly technologies. The use of plant extract to synthesize nanoparticles is thought to be an incredible green strategy. In the present study, leaf extract of Ficus benghalensis was chosen to synthesize the low cost and novel copper oxide (CuO) nanoparticles. The aim was to investigate the ability of these novel nano particles in removing Congo red dye from water. Various parameters including contact time, adsorbent dosage, initial dye concentration and pH of dye solution that affect the adsorption were optimized by carrying out batch adsorption experiments. The mechanism of pseudo-first-order, pseudo-second-order, Langmuir equilibrium isotherm, and Freundlich isotherm was investigated using kinetic and equilibrium experimental data. These models gave an insight into the adsorption kinetics and adsorption mechanism. The pH effect revealed that Congo red dye being an acidic dye showed good adsorption at acidic pH.  The findings of this work show that copper oxide nanoparticles are promising adsorbents for the removal of Congo red dye from aqueous based system.