Catalytic oxidation of phenol in wastewater using hydrogen peroxide

Sa？etak The use of catalysts in the processes of industrial wastewater treatment is the most effective manner both to improve the existing and to develop new efficient technologies, with a special emphasis on saving raw materials and energy as well as cost-effectiveness of the process. Catalytic oxidation of organic pollution using hydrogen peroxide is known as the CWPO method, an innovative procedure that fulfils the mentioned requirements. This paper, therefore, explores the activity and stability of calcined Cu/X-1273 catalyst in the phenol oxidation reaction with hydrogen peroxide. The catalyst characterization included x-ray diffraction analysis (XRD), scanning electron microscopy (SEM), elementary analysis (AAS) and determination of specific surface area by the standard BET method. Kinetic measurements were carried out at atmospheric pressure, different temperatures (323 K – 353 K) and constant concentrations of phenol (0.01 mol dm-3) and hydrogen peroxide (0.1 mol dm-3). The catalyst mass equalled 0.5 g dm-3, with the grain size ranging from 0.03 to 1.0 mm. Experimental data were tested using the following kinetic models for phenol oxidation: rF = kF cF cVP and for decomposition of hydrogen peroxide: rVP = kVP cVP + kF cF cVP. The kinetic parameters were assessed by the Nelder-Mead method of nonlinear optimization. The catalyst efficiency was monitored through phenol and hydrogen peroxide conversion and copper removal from the zeolite support. Based on obtained results, it was concluded that the activity and stability of the catalyst depend both on temperature and Cu/X-1273 grain size. In the reactions in which catalyst grains were larger than 3.25 mm, there was a marked interphase resistance in the transfer of matter for the phenol molecule, which was also confirmed by determining the activation energy