CATALYTIC OXIDATION OF 2-NITROPHENOL IN WATER OVER Fe(III), Co(II) AND Ni(II) ANCHORED MCM-41

Abstract

Common biological treatments are not very efficient in removing persistent pollutants from water, such as 2-nitrophenol. Oxidation to harmless constituents is the preferred method of treatment. 2-nitrophenol enters water from dyes, pesticides, plasticizer explosives and solvent industries. This paper describes the use of Fe(III), Co(II) and Ni(II) supported MCM-41 as catalysts for oxidizing 2-nitrophenol in water. Oxidation was carried out in the presence and absence of H₂O₂ and the effects of reaction time, mole ratio, catalyst load, reactant concentration, temperature, and pH were evaluated. The conversions achieved for Fe(III), Co(II) and Ni(II) anchored MCM-41 were 47.8, 50.4 and 52.2 % in the presence of H₂O₂ and 39.8, 55.8 and 58.8 % in the absence of H₂O₂, respectively (temperature 353 K, time 300 min, catalyst load 2 g L^-1, 2-nitrophenol 10^-3 M). The preparation of the catalysts and their characterization by atomic absorption spectrometry (AAS), cation exchange capacity (CEC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA) and nitrogen adsorption measurements is described. The oxidation process followed first order kinetics. Some of the oxidation products were identified by gas chromatography mass spectrometry and a probable mechanism is proposed.