Adsorption and catalytic oxidation of organic pollutants using Fe-zeolite

In this work, a natural zeolite, modified and loaded with iron (NZ-A-Fe) as a heterogeneous catalyst, was characterized for its suitability as a permeable reactive barrier (PRB) material for treatment of aromatic hydrocarbons in groundwater. Adsorption and oxidation processes were analyzed. Batch adsorption tests for benzene, toluene and xylene (BTX) aqueous concentrated solutions were performed at neutral pH. Kinetic adsorption was described with the pseudo-second-order model. Experiments were performed using a stirred batch reactor with near 11 mM initial BTX concentration applying NZ-A-Fe as solid catalyst and H2O2 as an oxidant. BTX removal reached 80% in 600 min in these experimental conditions. Catalytic oxidation was described with a pseudo-first-order kinetic model. No significant iron leaching was detected during all the experiences. These investigations show that coupling adsorption with catalytic oxidation with this novel system is a promising procedure to simultaneously remove BTX from moderately concentrated aqueous solution at neutral pH in groundwater.