Developments of modified magnetic nanoparticle‐supported heteropolyacid photocatalytic performances in methylene blue scavenger

Abstract

In this project, the Keggin‐type polyoxometalate, H5PMoV2O40 (denoted as PMoV), was immobilized on modified NiFe2O4 nanoparticles to produce a magnetically separable catalyst. This catalyst was characterized using X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FT‐IR), field emission scanning electron microscopy (FESEM), cyclic voltammetry (CV), energy‐dispersive X‐ray (EDX), and UV–vis diffuse reflectance spectroscopy (UV‐DRS). The synthesized catalyst demonstrated a high photocatalytic activity in the degradation of methylene blue (denoted as MB) as a pollutant under UV light irradiation. The catalyst could be readily separated from the photocatalytic system using the magnetic field, and the loss of activity was negligible when the catalyst was recovered in five consecutive runs. In addition, optimization was performed using multiresponse optimization and the desirability function approach of the central composite design (CCD). The effects of various factors, such as the catalyst amount, contact time, and pH, on the degradation of MB were investigated. Optimization results for the 20 mg/L MB showed that the maximum degradation efficiency of 95.8% at optimum conditions was: catalyst amount: 22.35 mg, pH = 7.81, and time: 67 min, at ambient pressure and temperature.