Efficient degradation of organic pollutants by peroxymonosulfate activated with MgCuFe-layered double hydroxide

Abstract

In this study, MgCuFe-layered double hydroxide (MgCuFe-LDH) was for the first time used as a catalyst for peroxymonosulfate (PMS) activation towards the degradation of aqueous organic pollutants. Compared with both MgFe-LDH and MgCuAl-LDH materials, MgCuFe-LDH exhibited significantly higher catalytic activity to activate PMS for the degradation of acetaminophen. The effects of catalyst loading, PMS dosage, reaction temperature and initial solution pH on the degradation efficiency of acetaminophen were investigated. Acetaminophen (5 mg L⁻¹) degradation at about 93.0% was achieved at 20 min by using 0.3 g L⁻¹ MgCuFe-LDH and 0.5 mM PMS. Under the same conditions, rhodamine B (RhB, 5 mg L⁻¹) can be almost completely decolorized (99.5%) within 45 min. Radical scavenger and electron paramagnetic resonance (EPR) experiments showed that sulfate radicals (SO₄˙⁻) and hydroxyl radicals (·OH) existed in PMS/MgCuFe-LDH system. The generated radicals played vital roles in the catalytic degradation of organic pollutants. A possible activation mechanism of PMS on MgCuFe-LDH was put forward. This study indicates that MgCuFe-LDH is a promising catalyst to activate PMS for the efficient degradation of organic pollutants.