Heterogeneous Fenton-like oxidation of naproxen using synthesized goethite-montmorillonite nanocomposite

Abstract

In this work, montmorillonite clay modified with nanoparticles of iron oxyhydroxides (MGO) was synthesized to be used as a catalyst for the degradation of naproxen (NPX). The characterization of MGO nanocomposite have been realized by different methods (XRD, BET, SEM-EDX, TEM and UV–vis). In aqueous solution, the performance of the new catalyst has been highlighted in the degradation of NPX compared to iron oxyhydroxides (goethite) when mixtures ages in the dark under the same conditions.The degradation efficiency of the NPX in mixture (NPX-MGO-H2O2) (10−5 mol L−1, 1 g L−1, 5.10−3 mol L−1) at pH = 3 achieved a 100% removal of NPX in 60 min with a rate constant of k = 10−1 min-1. The formation of iron (II) shows the involvement of Fenton process, which has been operated at pH = 3. The hydroxyl radicals have been demonstrated by the use of 1% of isopropanol as a scavenger. UV light significantly enhanced the reaction with 100% of degradation in only 10 min. A degree of mineralization of the order of 90% was obtained after 5 h. Several parameters that affect this process have been optimized as pH, MGO dosage and H2O2 concentration.The reusability of the nanocomposite was examined in several consecutive runs, and the degradation efficiency decreased only 5% after 4 repeated runs. This promising process is suitable for removal of recalcitrant pollutant of the environment.