Magnetically recoverable MgFe2O4/conjugated polyvinyl chloride derivative nanocomposite with higher visible-light photocatalytic activity for treating Cr(VI)-polluted water

Abstract

A facile three-step method was adopted to synthesize MgFe2O4/conjugated polyvinyl chloride (CPVC) nanocomposite. XRD, Raman, XPS, SEM, EDX, element mapping, and HRTEM analyses confirmed the formation of MgFe2O4/CPVC nanocomposite. The optical and magnetic properties of the obtained MgFe2O4/CPVC nanocomposite were measured using UV–Vis spectrophotometer and vibrating sample magnetometer, respectively. Through photocatalytic reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation, it can be noticed that MgFe2O4/CPVC nanocomposite had both improved visible-light photocatalytic activity (about 2.1 times that of MgFe2O4 nanoparticles) and good photocatalytic stability. Moreover, MgFe2O4/CPVC nanocomposite can also be easily recovered by use of a magnet. Based on electrochemical impedance, transient photocurrent response and Mott-Schottky measurement, the mechanism responsible for the enhanced photocatalytic activity of MgFe2O4/CPVC nanocomposite was proposed. Finally, MgFe2O4/CPVC nanocomposite was applied to photocatalytic treatment of the diluted black chromium electroplating solution at different pH. Results showed that MgFe2O4/CPVC nanocomposite had significant visible-light photocatalytic activity in treating the diluted black chromium electroplating solution over a wide pH range (1.4–10.3), and its treatment efficiency increased with the decrease of solution pH. Thus, MgFe2O4/CPVC nanocomposite has the potential to be a new magnetically recoverable, high-performance visible-light photocatalyst for treating Cr(VI)-polluted water.