Kinetics and Thermodynamic Studies of Oxytetracycline Mineralization Using UV/H2O2

Oxytetracycline (OTC), a widely used antibiotic, was taken as the model contaminant to study the kinetic and thermodynamic parameters of mineralization using a UV/H2O2 system. Mineralization experiments were carried out at different initial OTC concentrations of 0.0156-0.0531 M, initial H2O2 concentrations of 0.043-0.116M and at a temperature range of 20 - 50 degrees C. The OTC mineralization process was monitored by measuring the total organic carbon as well as H2O2 consumption. The analysis of mineralization data showed two phases of mineralization: phase I: 0 <= t <= 30 min and phase II: 30 <= t <= 180 min. Based on this, the kinetic and thermodynamic parameters were established. The order of reaction obtained for organic C and H2O2 is 0.624 and 0.599 (phase I) and 0.954 and 0.062 (phase II), respectively. Based on this kinetic model, the OTC degradation rate constants were 0.0069 min(-1) (phase I) and 0.0051 min(-1) (phase II). The activation energy for phase I and phase II oxidation was 10.236 and 9.913 kJ mol(-1), respectively. The estimated Delta(#)G and Delta H-# values are positive, whereas negative Delta S-# values were obtained.