Homogeneous and heterogeneous AOPs for rapid degradation of Triton X-100 in aqueous media via UV light, nano titania hydrogen peroxide and potassium persulfate

Feasibility of degradation of Triton X-100 as a widely used and resistive surfactant in aqueous media was studied via some homogeneous and heterogeneous AOPs of UV/TiO2, UV/H2O2 and UV/S2O82-. For treatment of solutions containing 20 mg/L of Triton, the optimum obtained conditions are: 5.0 mg/L of nano TiO2. 270.3 mg/L of KPS, and 34.0 mg/L of H2O2 (1 mM of the oxidants), initial natural pH of 5.4 and temperature of 45 C. Under these conditions, the degradation efficiency for the UV/TiO2. UV/H2O2 and UV/S2O82- processes exceeds 71.9% (in 60 min), 80.9% (in 60 min) and 98.5% (in only 30 min) respectively. It was found that simultaneous application of these heterogeneous and homogeneous AOPs (UV/TiO2/H2O2 or S2O82-) is not desirable due to some physico-chemical retarding effects. The influence of temperature on the reactions was examined in the range of 15-45 degrees C and a kinetic power law model jointed with the Arrhenius equation was introduced. A pseudo first order reaction rate is appropriate for UV/S2O82- and UV/TiO2 processes under optimum conditions, while this order for UV/H2O2 process is 2.27. Meanwhile, the initial rates of degradation in UV/TiO2 process can be described well by the Langmuir-Hinshelwood kinetic model. Analysis of energy consumptions (thermal and electrical) revealed that increasing in temperature is an effective factor for lowering the energy cost of the preferred process of UV/S2O82-. (C) 2010 Elsevier B.V. All rights reserved.