Plant-Mediated Synthesis of Metal Oxide Nanocomposites for Environmental Remediation

Abstract

The presence of toxic dyes and other toxic elements in the effluents of textile, lather industries, paper mills, etc., is now a great threat to the environment. At present, the elimination of these toxic elements is the subject of considerable concern of environmental remediation. Oxide-based nanomaterials are considered as the areas of great research for the degradation of environmental pollutants. However, the photocatalytic efficiency of these pure semiconductors is still far from the practical applications because the recombination rate of photogenerated electron-hole pairs is very high in them. To solve this problem, many strategies have been proposed, such as doping with foreign ions, combining with other semiconductors, increasing of surface areas, and formation of semiconductor heterojunctions with properly aligned band structure. But the chemical methods, which are employed for the synthesis of these nanomaterials, involve the use of harmful chemicals. Thus, environmental friendly processes need to be adopted for the synthesis of these nanomaterials through biomimetic approaches. Compared to other biological materials, the plant extracts (PEs) have great potential towards synthesis of stable nanomaterials, as the biomolecules of plants act both as reducing and as stabilizing agents. It is experimented that the biosynthesized nanocomposites showed remarkable activity towards the degradation of environmental pollutants. But scanty literature is available on the synthesis of bio-based nanocomposites. Thus, more research work on “bio-based nanomaterials” is very much necessary for their applications in environmental pollution abatement. This chapter discusses the plant-mediated synthesis of metal oxide nanocomposites and some of their applications towards environmental remediation.