engleski

Hydrogen Peroxide Promoted Catalytic Wet Air Oxidation of Phenol

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. The Catalytic Wet Air Oxidation (CWAO) process is one of the most promising technologies to treat aqueous hazardous wastes, especially when these are too dilute to incinerate and too concentrated for a biological treatment. However, typical CWAO conditions are in the high temperature (353 – 473 K) and pressure (1-10 MPa), which leads to an increased cost of the treatment process. An alternative to lower CWAO operation conditions or to treat some refractory compounds is to supply little amount of a stronger oxidant such as hydrogen peroxide in a process referred as to Peroxide Promoted Catalytic Wet Air Oxidation (PP-CWAO). In this work catalytic activity and stability of Cu/13X zeolite in PP-CWAO of phenol was examined. Catalyst samples were prepared by ion exchange method of the protonic form of commercial zeolite. The catalysts were characterized by powder X-ray diffraction (XRD), AAS, while the adsorption techniques were used for the measurement of the specific surface area. The catalytic tests were carried out in a stainless steel Parr reactor in batch operation mode at the constant temperature (333 K), mass of catalyst (0.1 g / 200 cm3) and different air pressure (2-20 bar). The initial concentration of phenol was 0.01 mol dm-3 while the concentration of hydrogen peroxide varies from 0.01 mol dm-3 to 0.14 mol dm-3. The experimental profiles for phenol and TOC conversions using hydrogen peroxide as promoter in CWAO have been compared to those obtained in the CWAO and CWPO. Based on the results it has been concluded that PP-CWAO process is more efficient than classical CWAO and CWPO processes.

PP-CWPO; phenol; catalyst; Cu/13Xstability

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