Photo-Fenton like reaction for the degradation of methyl orange using magnetically retrievable NiFe2O4/CoMoS4 heterojunction photocatalyst

Abstract

In this study, magnetically recyclable NiFe2O4/CoMoS4 heterojunction was synthesized by the one-pot hydrothermal method before being characterized using XRD, FTIR, Raman, TGA, SEM, TEM, BET, EIS, UV–vis DRS, and XPS, respectively. Its bandgap of 2.01 eV aided in the absorption of more visible light for the production of reactive radicals. The heterojunction photocatalyst realized 99.0 % after 60 min when used for photo-Fenton degradation of methyl orange (MO) dye. The enhanced photo-Fenton degradation was associated with efficient charge separation as indicated by Nyquist plots of electrochemical impedance spectroscopy (EIS), improved BET surface area, and high synergy effect from Fenton and photocatalytic processes. The composite material has a low crystallite size (4.3 nm) emanating from a broad diffraction peak compared to pure NiFe2O4 (25 nm). A 50 % TOC removal was recorded after 60 min of MO degradation reaction. Scavenger tests showed that HO• and •O2− were the main reactive radicals responsible for the MO degradation. The NiFe2O4/CoMoS4 heterojunction revealed a minimal electrical energy (13.744 kWh/m3) consumption and performance loss in five consecutive cycles. Hence, it is inferred that these nanomaterials are highly suitable for the degradation of textile wastewater.