• DIPTI VAYA

Articles written in Bulletin of Materials Science

• Photocatalytic degradation of Malachite Green dye by modified ZnO nanomaterial

In this article we report a chemical sol–gel approach to synthesize zinc oxide nanomaterials capped with ethylene diamine tetra acetic acid (EDTA), citric acid and oleic acid, and to study the effect of the surface modification on their photocatalytic activity and the kinetics for the degradation of Malachite Green (MG) dye. The structural, optical and chemical features were systematically characterized by X-ray powder diffraction, scanning electron microscopy, Fourier transform infrared and UV–vis absorption spectroscopy. The objective of using the capping agents was to confine the size and control the growth and morphology of the nanomaterial. The smallest crystallite size was recorded as 29 nm for EDTA-capped rod-shaped ZnO. A comparison study of the effect of thethree different capping surfactants on ZnO nanomaterial for photocatalytic degradation ofMGdye under solar light showed that EDTA with higher denticity coordinated efficiently with the surface of ZnO nanocrystalline catalystsand hence demonstrated better decolouration of the dye under solar light. The dye degradation followed the psuedofirst-order kinetics. EDTA proved to be the best capping agent among all the three for ZnO nanomaterial.

• Photocatalytic degradation of malachite green dye by ZnO and ZnO–${\beta}$-cyclodextrin nanocomposite

Water, the primary source of life, is contaminated with various organic/inorganic impurities in the course of development. Organic dyes, a waste product from dying industries, have evolved as one of the major contributor to water pollution. The present work involves the photocatalytic degradation of malachite green dye as a model substrate using zinc oxide nanoparticles (ZnO NPs) and its composite with ${\beta}$-cyclodextrin (${\beta}$-CD). ZnO NPs are found to be a worthy catalyst due to their bandgap and easy availability. The role of ${\beta}$-CD in ZnO photocatalyst is explored. With ZnO NPs, electron–hole recombination takes place very easily; hence, to restrict this recombination ${\beta}$-CD has been used. We have characterized the synthesized nanomaterials by using powder X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, diffuse reflectance spectroscopy (DSR), scanning electron microscopy and transmission electron microscopy (TEM). Various parameters, such as the concentration of dye, pH and amount of catalyst have optimized for the photocatalysis process. More basic medium adsorption is more favourable than degradation, which decreases the reusability of the catalyst. Based on the photodegradation efficiency and rate constant (k), we observed that ZnO–${\beta}$-CD showed better photocatalytic activity than ZnO NPs. The plausible mechanism for photocatalytic degradation has also been reported with the help of photoluminescence spectra and scavenger activity.

• # Bulletin of Materials Science

Volume 45, 2022
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020