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UV and visible activation of Cr(III)-doped TiO2 catalyst prepared by a microwave-assisted sol–gel method during MCPA degradation

journal contribution
posted on 2023-05-19, 20:32 authored by Mendiola-Alvarez, SY, Guzman-Mar, JL, Turnes-Palomino, G, Fernando Maya AlejandroFernando Maya Alejandro, Hernandez-Ramirez, A, Hinojosa-Reyes, L

Photocatalytic degradation of 4-chloro-2-methylphenoxyacetic acid (MCPA) in aqueous solution using Cr(III)-doped TiO2 under UV and visible light was investigated. The semiconductor material was synthesized by a microwave-assisted sol–gel method with Cr(III) doping contents of 0.02, 0.04, and 0.06 wt%. The catalyst was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), nitrogen physisorption, UV–Vis diffuse reflectance spectroscopy (DRS), and atomic absorption spectroscopy (AAS). The photocatalytic activity for the photodegradation of MCPA was followed by reversed-phase high-performance liquid chromatography (HPLC) and total organic carbon (TOC) analysis. The intermediates formed during degradation were identified using gas chromatography–mass spectrometry (GC–MS). Chloride ion evolution was measured by ion chromatography. Characterization results showed that Cr(III)-doped TiO2 materials possessed a small crystalline size, high surface area, and mesoporous structure. UV–Vis DRS showed enhanced absorption in the visible region as a function of the Cr(III) concentration. The Cr(III)-doped TiO2 catalyst with 0.04 wt% of Cr(III) was more active than bare TiO2 for the degradation of MCPA under both UV and visible light. The intermediates identified during MCPA degradation were 4-chloro-2-methylphenol (CMP), 2-(4-hydroxy-2-methylphenoxy) acetic acid (HMPA), and 2-hydroxybuta-1,3-diene-1,4-diyl-bis (oxy)dimethanol (HBDM); the formation of these intermediates depended on the radiation source.


Publication title

Environmental Science and Pollution Research










School of Natural Sciences


Ecomed Publishers

Place of publication

Rudolf-Diesel-Str 3, Landsberg, Germany, D-86899

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Copyright 2017 Springer-Verlag Berlin Heidelberg

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Socio-economic Objectives

Expanding knowledge in the chemical sciences