Hexavalent chromium removal by titanium dioxide photocatalytic reduction and the effect of phenol and humic acid on its removal efficiency

Malakootian, Mohammad; Mansuri, Fatemeh

doi:10.4103/2277-9183.157720

Hexavalent chromium removal by titanium dioxide photocatalytic reduction and the effect of phenol and humic acid on its removal efficiency

Document Type : Original Article

Authors

Mohammad Malakootian

Fatemeh Mansuri

Environmental Health Engineering Research Center, Department of Environmental Health, Kerman University of Medical Sciences, Kerman, Iran

10.4103/2277-9183.157720

Abstract

Aims: The aim of this study is Cr (VI) removal by titanium dioxide (TiO2) photocatalytic reduction and the effect of phenol and humic acid (HA) on its removal efficiency are investigated. Materials and Methods: The experiments were performed on both simulated synthetic wastewater and real wastewater. Various parameters such as pH, contact time, Cr (VI) and TiO ₂ concentrations, and a constant concentration of phenol and HA were considered to perform the experiments. Results: The removal value of Cr (VI) alone is 81% and in combination with HA and phenol is 89.7% and 96.2%, respectively. Cr (VI) removal efficiency was enhanced by decreasing pH and contact time. With increasing TiO ₂ dosage, the removal of Cr (VI) increased, up to 0.5 g/L and then decreased at 1 g/L. Cr (VI) removal efficiency decreases with the increase of Cr (VI) initial concentration. Removal efficiency, in 10 mg/L initial concentration of phenol and HA, was enhanced as contact time increased. Equilibrium data and adsorption process kinetics obey Langmuir isotherm model and pseudo second-order kinetic model, respectively. Conclusions: Heavy metal ions and organic pollutants are often present in real wastewater. This research suggests that the photocatalytic reaction TiO ₂ could be applied to more effectively treat wastewaters containing both Cr (VI) and organic compounds.

Keywords

Chromium

humic acid

phenol

titanium dioxide