Ozone initiated oxidation of environmentally unfriendly organic compounds is one of the powerful tools that is utilized to convert and/or completely mineralize these substances. Here we have adopted the adsorption phenomenon in combination with ozonation (0.123 mg/L) of the hazardous cresol isomers mounted in a glass column. An oxide of aluminum (gamma-Al2O3) or silicon (SiO2) was used as an adsorbent material. These materials were characterized using XRD, SEM and TEM techniques. Various cresols (m-, o-, p-cresol) were oxidized for different time intervals, viz. 1, 3 and 5 h. The gamma-Al2O3 adsorbent was found to have a relatively high catalytic effect towards conversion of m-cresol (52) into oxidation products, whereas SiO2 promoted the conversion of o-cresol (57) and p-cresol (62) the most. The resultant oxidation products that were identified using GC-MS were dominantly isomeric from all three cresols. Oxidation of m-cresol produced m-tolyl acetate (m-TA), 2,3-dihydroxytoluene (2,3-DT) and diethyl maleate (DM) whereas o-cresol produced o-tolyl acetate (o-TA), 2,5-dihydroxytoluene (2,5-DT) and DM. Finally, the oxidation of p-cresol produced p-tolyl acetate (p-TA), 3,4-dihydroxytoluene (3,4-DT) and DM. Amongst all identified oxidation products, tolyl acetates recorded highest percentage selectivities from all adsorbates especially in 1 h reactions.
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