Controlled synthesis and characterization of electron rich iron(iii) oxide doped nanoporous activated carbon for the catalytic oxidation of aqueous ortho phenylene diamine

Abstract

This work reports the degradation of biorefractory aqueous ortho-phenylenediamine (OPD) by hydrogen peroxide and iron(III) oxide doped nanoporous activated carbon (Fe-NPAC). The Fe-NPAC was prepared by a hydrothermal method. The catalyst was characterized using BET surface area and porosity analyzers, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The effect of pH, (1–10); catalyst dosage, (Fe-NPAC, 0.1 g, 0.2 g, 0.3 g); H₂O₂ concentration, (1.76 mmol, 3.52 mmol, 5.29 mmol, 7.05 mmol and 8.82 mmol) and OPD concentration on the catalytic activity was evaluated. The catalytic oxidation of OPD by H₂O₂–Fe-NPAC₄₀₀ was confirmed using UV-Visible and emission spectroscopy. The chemical oxygen demand (COD) was reduced by 96% within 180 min in the presence of Fe-NPAC₄₀₀, which is about 20-fold higher than the control (without Fe-NPAC₄₀₀). Moreover, Fe-NPAC₄₀₀ was demonstrated to have excellent stability and reusability characteristics.