Degradation of the Antibiotic Ceftriaxone by Fenton Oxidation Process and Compound Analysis

ABSTRACT

Fenton oxidation process is used to degrade the recalcitrant pharmaceutical product ceftriaxone (CF), a commonly-used antibiotic in Malaysia. An effluent containing ceftriaxone antibiotic whose chemical oxygen demand (COD) and total suspended solids (TSS) was found to be 944 mg l−1 and 280 mg l−1 respectively. Physical and chemical treatment methods were employed to find the optimal concentration of Fenton reagent which was needed to degrade the antibiotic to a safe disposal level. Physical treatment included the variation in temperatures (37°C, 42°C, 47°C and 50°C) and pH (2.6, 5.2, 6.1 and 10). The molar concentration of Fenton reagent was varied at 0.1, 0.2, 0.3, 0.35 and 0.4 M. The molar ratio of ferrous ions (Fe2+) to hydrogen peroxide ions (H2O2) in Fenton reagent was varied at 1:2, 1:4, 1:8 and 1:10. The optimum conditions for maximum reduction in COD level were at pH 2.6, 0.4 M of Fenton reagent and Fe2+/H2O2 ratio of 1:8, reaching 84.6% reduction within 30 min of reaction. The experiment was carried out at ambient temperature 28°C and at atmospheric pressure. A further investigation (pH and temperature variation) was made to deduce the percentage of reduction in terms of COD and TSS level that were obtained by the optimum sample. Findings reveal that a significant decrease of 76.5% was observed at 47°C and pH 5.2. Total suspended solid investigation reveals that a maximum reduction of 93% occurred at 0.4 M of Fenton reagent having the ratio of Fe2+/H2O2 of 1:2. Furthermore, 8 intermediates (5-thiazolecarboxylic acid, 5-[5-(methoxymethyl)-1,2-oxazol-3-yl]-4H-1,2,4-triazole-3,4-diamine, methanone bis [(methylthio)oxidoamino], 5-{[2,6-dimethyl-4-(2-methyl-2-propanyl)benzyl]sulfonyl}-1-pentanol, benzene 5-(1,1-dimethylethyl)-2-[[(2-ethoxyethyl)sulfonyl]methyl]-1,3-dimethyl, 3D 1-(ethylsulfonyl)-5-methoxy-6,6-dimethyl-4-heptanol, 3-{[2,6-dimethyl-4-(2-methyl-2-propanyl)benzyl]sulfonyl}-1-propanol and 2R-3-[(S)-{(1R)-1-[4-(2-methyl-2-propanyl) phenyl]ethyl}sulfinyl]-1,2-propanediol were identified from the degradation products obtained by LC/MS analysis.

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