Photocatalytic degradation of textile dyes laden industrial wastewater using fabricated bismuth ferrite coated nickel/nickel oxide foam

Abstract

Inadequate wastewater treatment infrastructure is a major environmental and public health concern worldwide. Industrial effluents containing organic pollutants such as dyes constitute a severe challenge due to their toxicity. Malachite green (MG) and methylene blue (MB) are two organic dyes that are widely used in textiles but also damage the environment. Herein, we report the fabrication of bismuth ferrite-coated nickel/nickel oxide foam (BFCNF) heterojunction photocatalyst via the dip-coating approach. The point of zero charge and the estimated surface area of BFCNF was observed to be 7.5, and 213.19  m² g⁻¹, respectively. Energy dispersive X-ray (EDX) spectra revealed the presence of Ni, O, Bi, and Fe elements in the BFCNF. The scanning electron microscopy (SEM) analysis revealed that BFCNF has a granular coarse surface morphology. The XRD anslysis showed that the average-crystallite size for Ni/NiO, BFO, and BFCNF was found to be 28, 1.00, and 1.00 nm, respectively. The catalyst revealed outstanding performance while degrading 97 % of MG dye at pH 6, and 98 % MB dye at pH 5, under visible light irradiation of 20 min. The chemical oxygen demand (COD) studies were also performed for both of the dyes. Notably, a negligible COD was observed for both of the dyes after 80 min. In a real industrial wastewater treatment study, the catalyst almost degraded 99 % of both dyes. Further, the catalyst revealed excellent stability during four and seven consecutive recycles tests for MB and MG dyes, respectively. The degradation process follows pseudo-first-order kinetics with correlation coefficients (regression analysis, R ²) of 0.949 and 0.974 for MG and MB, respectively. To the best of our knowledge, this is the first report on utilization of bismuth ferrite-coated nickel/nickel oxide foam based heterojunction photocatalyst. This work will trigger the development of highly efficient catalysts for efficient wastewater treatment.