Photocatalytic performance and photodegradation kinetics of Fenton-like process based on haematite nanocrystals for basic dye removal

Abstract

Photo-Fenton’s reagent based on haematite nanocrystals was investigated to oxidize simulated textile wastewater streams loaded with methylene blue (MB) dye to signify the role of nanocrystals in the Fenton system. Various oxidation systems were compared such as UV photocatalysis, H2O2, dark Fenton’s reagent and nanohaematite photo-Fenton reaction. Different operating parameters were investigated, and the maximum oxidation rate reached 70% at the optimal experimental conditions of 40 mg/L nanohaematite, 400 mg/L H2O2 and initial pH at 3.0 within 90 min of reaction time. Furthermore, temperature increases showed increment in the reaction rate. Also, the reaction kinetics was studied and the system followed the pseudo-second-order model. Finally, thermodynamic parameters, i.e., ∆G′, ∆H′ and ∆S′, for MB oxidation with photo-Fenton system were investigated and the data illustrated that the reaction was exothermic with non-spontaneous nature.