Current scenario on biogenic synthesis of metal oxide nanocomposites using plant specimens and their application towards treatment of wastewater

Abstract

Various industries such as textile, leather, and paper mills discharge huge amount of industrial effluents to the environment containing unconsumed dyes and toxic heavy metal ions which are very harmful and carcinogenic in nature. The increase in water pollution is adversely impacting the ecosystems and human health. Now, it has become a great challenge to treat the contaminated water/wastewater. Photocatalysis and adsorption are the two techniques gaining significant attention for the removal of toxic pollutants from wastewater effectively. In this regard, metal oxide-based nanomaterials and their composites have gained profound attention in photocatalytic degradation as well as adsorptive removal of toxic pollutants from water due to their chemical reactivity, higher surface area, regeneration efficiency, ample adsorption sites, intriguing photocatalytic activity, and cost-effectiveness. However, the conventional methods, employed to synthesize these metal oxide nanocomposites, involve the use of toxic chemicals which again produce secondary pollutants. Among all biological materials, the use of plant biomolecules is found to be the most effective way to synthesize stable nanomaterials, as the phytoconstituents of plants act as reducing, capping, and stabilizing agent. It is experimentally proved that bio-based nanocomposites have tremendous potential towards the degradation of environmental pollutants. Thus, there is a great need to work on the synthesis of some novel plant-based metal oxide nanocomposites and their applications in the field of water treatment. This review mainly discusses the metal oxide nanocomposites synthesized using plant specimens and their various applications towards treatment of water/wastewater.