Photocatalytic degradation of Rhodamine B in greywater over ZnO/BiObr/MgFe2O4 Ternary Nanocomposite under sunlight irradiation: performance evaluation, kinetic and phytotoxicity studies

Lim, Khar Lok (2022) Photocatalytic degradation of Rhodamine B in greywater over ZnO/BiObr/MgFe2O4 Ternary Nanocomposite under sunlight irradiation: performance evaluation, kinetic and phytotoxicity studies. Final Year Project, UTAR.

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Abstract

Extensive use of dye in various industries, particularly textile industries, along with the leaching from household sources into greywater has led to environmental and human health hazard. Among the existing advanced oxidation processes (AOPs), semiconductor-mediated photocatalysis is intensively recognized as a potential and promising alternative for the treatment of dye effluent. In this study, a new, efficient and magnetically separable ZnO/BiOBr/MgFe2O4 nanocomposite was successfully fabricated via a facile ultrasonic-precipitation method. A series of analytical characterization methods were employed to examine the physicochemical and optical properties of prepared photocatalyst. FESEM showed the homogeneous adhesion of ZnO nanoparticles and MgFe2O4 nanorods on the two-dimensional BiOBr nanosheets, forming a ternary heterostructure. UV-vis DRS confirmed the elevated visible light photosensitivity and reduced band gap of prepared ZnO/BiOBr/MgFe2O4 nanocomposite. Photocatalytic performance of ZnO/BiOBr/MgFe2O4 was investigated by the degradation of RhB in both aqueous solution and greywater under solar light illumination. As compared to the single-phase component photocatalysts, the prepared ZnO/BiOBr/MgFe2O4 exhibited remarkably enhanced photocatalytic activity with RhB degradation efficiency up to 96.14% and 93.59% in aqueous solution and greywater, respectively, with corresponding apparent rate constant of 0.0153 min-1 and 0.017 min-1 after 180 min irradiation. The boosted photoactivity of nanocomposite was attributed to the synergistic effect among the ZnO, BiOBr and MgFe2O4 which significantly reduced the charge carrier recombination and improved the charge migration behaviour.The phytotoxicity study also revealed that the phytotoxicity of RhB has been substantially reduced after the photocatalytic degradation over the as-synthesized ternary composite. The present work paves the way for future development and vii potential application of ZnO/BiOBr/MgFe2O4 in remediation of wastewater and household greywater

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