Wet Air Oxidation of Phenol on Oxides of Fe(III), Mn(IV), Ti(IV) and Goethite

Title:Wet Air Oxidation of Phenol on Oxides of Fe(III), Mn(IV), Ti(IV) and Goethite

Volume: 11 Issue: 1

Author(s): Gitali Baruah*, Linton Hazarika, Kishor K. Shah and Krishna G. Bhattacharyya

Affiliation:

• Department of Chemistry, Pandu College, Guwahati, Assam PIN- 781012, India

Keywords: Oxidation, phenol, H₂O₂, goethite, catalysts, HPLC.

Abstract:

Background: Phenol and its derivatives exist in water bodies due to the discharge of polluted wastewater from industrial, agricultural, and domestic activities into water bodies. Various industries like pharmaceutical, petrochemical and coal processing industries discharge phenolic compounds into water bodies. Phenol and substituted phenols are quite toxic to humans.

Objective: Oxidative destruction of phenol in water was carried out at ambient temperature by using laboratory-synthesized goethite and commercial Fe₂O₃, TiO₂, and MnO₂ as catalysts in the presence and the absence ofH2O2.

Methods: The reactions were carried out in a batch reactor in 100 mL conical flasks. After mixing the reactants (Phenol and H₂O₂) and the catalyst in appropriate amounts, the flasks were capped, and the contents were agitated in a water bath shaker (NSW, India) at a constant temperature of 300 K for a predetermined time interval.

Results: The results have been characterized in terms of percentage destruction of the Phenol. The catalyst Goethite was able to bring about 15.8 to 23.5% destruction as the reactant-H₂O₂ mole ratio was increased from 1:1 to 1:20 with a fixed catalyst load of 0.2 gL^-1. The total conversion of phenol increases smoothly with an increase in the reaction time from 60 to 300 min in all cases except Fe₂O₃, in which case the reaction does not advance after 60 min. Interestingly, the catalyst MnO₂, brings about 94.4 % oxidative conversion of phenol with the same loading in the absence of H₂O₂, i.e., in wet air oxidation. It is also found that a 1:1 mixture of MnO₂ + TiO₂ gives 100 % conversion for a catalyst load of ≥ 6 gL^-1 in the absence of H₂O₂.

Conclusion: It is found that phenol could be completely oxidized to harmless end products at room temperature. For this purpose, MnO₂ has been found to be the most active catalyst among the ones tested, whether H₂O₂ is present or not in the reaction mixture. The three oxides Fe₂O₃, goethite and TiO₂ can perform better only in the presence of H₂O₂.

Cite this article as:

Baruah Gitali*, Hazarika Linton, Shah K. Kishor and Bhattacharyya G. Krishna, Wet Air Oxidation of Phenol on Oxides of Fe(III), Mn(IV), Ti(IV) and Goethite, Current Catalysis 2022; 11 (1) . https://dx.doi.org/10.2174/2211544711666220713091022