An Overview of Physical Properties of Fruit Wastes Mediated Green Synthesized Transition Metal Oxide Nanoparticles and Its Applications

Abstract

Different fruit peel wastes have a scope of utilizing in green synthesis of various transition metal oxide nanoparticles (TrMONPs). This articles reveals about the physical properties and their applications of green synthesized TrMONPs mediated through fruit peel wastes. Various transition metal nanoparticles like Ag, Au, Ti, Zn, Cu, Fe, Ni, Pd have been synthesized successfully by peels of mango, banana, pomegranate, apple and other citrus fruits. The SEM analysis revealed that the most of the synthesized silver nanoparticles were spherical in the range of 10 to 15 nm and have wide applications as antimicrobial agents, sensors, conducting materials, etc. ZnONPs were synthesized by mediated through most of the fruit peels found in range of 20 to 50 nm (spherical shape) with applications as photocatalyst. TiO2 nano-particles synthesized were spherical and hexagonal with high optical properties as well as UV absorbent nature targeting applications in cosmetics. The other metals viz. Au Cu, Ni, Pd nanoparticles synthesized mediated citrus fruit peels showed crystallinity. SEM analysis confirmed the surface morphology while XRD confirmed the high crystallinity of the metals nanoparticles. FT-IR have been widely used by the researchers for confirmation of new bond formation in nanoparticles. It is also evident that scandium and vanadium from 3d-series and other 4d-transition metals are less approachable and not used in fruit peel waste mediated green synthesis. The nanoparticles of Ni, Pd, Zr, Cu, Fe and other metals (TrOMNPs) have also been found with optimum surface area and size less than 10 nm for adsorption due to which these have application as catalyst in many organic synthesis. Other applications are biochar, bio-sorbent, carbon dots, edible films, heavy metals absorption, waste water treatment and in medicinal fields. Furthermore, approaches that can aided into development of these nanoparticles is the perspective towards incorporating green methods like laser ablation, sol-gel process, microwave heating, chemical vapour deposition and hydrothermal/solvothermal process into production of fruit wastes derived metal nanoparticles. Recent trends of researchers are towards nanosorbents for the removal of air and water pollutants along with other fields by using fruit and food wastes material.