Remediation of arsenic(III) from aqueous solutions using zero-valent iron (ZVI) combined with potassium permanganate and ferrous ions.

A system of zerovalent iron combined with potassium permanganate and ferrous irons (Fe(II)-KMnO4-ZVI) was used to remove As(III), one of the most poisonous wastewater pollutants. The Fe(II)-KMnO4-ZVI system was characterized by using X-ray photoelectron spectroscopy and scanning electron microscopy. The As(III) removal efficiency by the Fe(II)-KMnO4-ZVI system under different conditions was investigated and the experimental data were fitted to adsorption kinetics and isotherm models. As(III) could be removed by both physisorption and chemisorption through mixing adsorbents in a very short time (minute scale) with high removal ratios (more than 99.5%) over a wide range of pH (1-9) and concentration (20-100 mg/L). The removal of As(III) by the Fe(II)-KMnO4-ZVI system agreed well with pseudo-first-order reaction kinetics and pseudo-second-order reaction kinetics. The Freundlich isotherm provided a good model of the adsorption system, indicating that the Fe(II)-KMnO4-ZVI system has heterogeneous structure. The results show that the Fe(II)-KMnO4-ZVI system exhibited a high removal efficiency for As(III), which suggested that it might be an effective material for As(III) remediation.