Application of TiO2 and ZnO nanoparticles immobilized on clay in wastewater treatment: a review

Abstract

Increase in industrial and anthropogenic activities leads to a decline in water quality. This necessitates the need for the removal of contaminants from industrial and domestic wastewater. Clay minerals are naturally abundant and non-toxic materials that found to be useful for remediation of emerging contaminants from wastewater. This review paper presents an insight into clay, the simplest material (in solgel techniques) for the synthesis of TiO2 and ZnO, mechanisms of their reactions, analytical techniques used for characterizations, and their nanocomposites for wastewater treatment. Nanomaterials, such as nanoclay, titanium, and zinc oxide, have offered the opportunities of sequestering variety of pollutants in wastewater. TiO2 and ZnO anchored on clay have been found to be good promising sequesters and have been explored for wastewater remediation via nanotechnology. This water treatment method includes adsorption/absorption, photocatalysis, and microbial disinfection. These nanocomposites provide more active surface sites and reduce the agglomeration of the nanoparticles, but leaching has been their shortcomings. To overcome this, the filtration technique may become significant for the removal and avoidance of fouling of wastewater. This can be achieved through the fabrication of nano-based filters using the nanocomposites