Natural clinoptilolite–zeolite loaded with iron for aromatic hydrocarbons removal from aqueous solutions

Abstract

The aim of this work is to explore the potential use as catalyst in aromatic hydrocarbons removal, a natural zeolite loaded with zerovalent iron. For this purpose, an iron precursor, FeSO₄·7H₂O, was first imbibed, later reduced and confined on the surface and/or inside of a zeolite, being present in a form of α-Fe nanoparticles with good catalytic properties. The supported catalyst samples were characterized structurally and morphologically. Benzene was selected to represent the organic contamination in these experiments. Fixed bed experiments were conducted using a vertical glass column. A saturated aqueous benzene solution (22.5 mM) was continuously pumped (0.5 ml/min) into the column simultaneously with the amount of H₂O₂ (30 %) necessary (12.5 ml) for the reaction in up flow mode. The pH was fixed at 3–4 with a buffer solution. All experiments were performed at 20 °C. The hydraulic retention time of benzene inside the column was estimated in 40 min. Benzene degradation, in the presented experimental conditions, is near 80 % and the process shows good stability for at least 600 min. Neither Fe(II) nor Fe(III) is detected in the eluded solution. This novel heterogeneous catalyst was demonstrated as a potent Fenton catalyst which provided an attractive alternative for the treatment of organic pollutants in water/wastewater.