Iron pillared vermiculite as a heterogeneous photo-Fenton catalyst for photocatalytic degradation of azo dye reactive brilliant orange X-GN

In the present study, a novel heterogeneous photo-Fenton catalyst was prepared by iron pillared vermiculite (Fe-VT). The catalyst Fe-VT was characterized by laser particle size analyzer, X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods. It was found that hydroxy-Fe of low polymerization degree intercalated into the silicate layers of vermiculite successfully. Under the following experimental conditions: 100 mg/L reactive brilliant orange X-GN (named as X-GN) solution, pH 3, 30 °C, 3.92 mM H2O2 and 0.5 g/L Fe-VT dosage, 98.7% decoloration and 54.4% TOC removal could be achieved with 75 min UV irradiation. The kinetics results showed that decoloration kinetics of X-GN was well fitted by a pseudo-first order equation. In addition, the maximum dissolved iron, determined by atomic absorption spectrophotometer (AAS), was less than 1 ppm, while decoloration efficiency was till higher than 90% after the catalyst Fe-VT being used for 3 cycles. Hence, taking into account the favorable photocatalytic properties and low leaching of iron ions, iron pillared vermiculite is a promising catalyst for dye wastewater treatment.