Photocatalytic degradation of dyes and removal of bacteria using biosynthesised flowerlike NiO nanoparticles
K Motene, LM Mahlaule-Glory, NM Ngoepe, Morongwa Mary Mathipa, NC Hintsho-Mbita
Abstract
The removal of pollutants such as dyes and bacteria has become a tedious process hence there is a need for multifunctional materials that can be used for the removal or degradation of various pollutants from wastewater. In this study, a flowerlike NiO nanoparticle was synthesised and used for the removal of dyes and bacterial from water. Sutherlendia frutescene plant extract was used as a reducing agent. SEM and XRD confirmed the formation of this material through morphological analysis and phase identification, respectively. EDX further corroborated the formation with the present dominant phases of Ni and O. TGA showed the material was stable, furthermore, UV-Vis was able to demonstrate the optical properties of the material with excitation at the absorption wavelength of 302 nm and with a bandgap of 3.5 eV. This material was further tested for the degradation of two dye pollutants, methylene blue and malachite green. A percentage degradation of 89% and 98%, respectively, was achieved. The materials could be reused at least three times before losing their stability. Upon testing the model bacterial strains, E. faecalis and P. aurugenosa,the SfNiO activity was more active towards gram-positive bacteria. This study has shown that it is possible to produce environmentally safe materials that can be used for the degradation of various dyes and removal of both gram-negative and gram-positive bacterial strains in our water streams.