摘要
In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/ carbon-zeolite and Pd/carbon-CeO2 nanocatalysts. Acti- vated carbon was obtained from pine cone chemically activated using ZnC12 and modified by HaPO4. Natural zeolite of clinoptilolite was with HC1, while nano-ceria modified by acid treatment was synthesized via redox method. Mixed supports of carbon-zeolite and carbon- ceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray emission scanning electron diffraction （XRD）, field microscopy （FESEM）, Brunauer-Emmett-Teller surface area （BET）, Fourier transform infrared spectroscopy （FTIR） and thermogravi- metric （TG） techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation ofnano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts （-1000 m^2·g^-1）. FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100℃-250℃. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds （VOCs）, represent- ing high catalytic performance of 98% for the abatement of xylene at 250℃. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocata- lysts.
In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/ carbon-zeolite and Pd/carbon-CeO2 nanocatalysts. Acti- vated carbon was obtained from pine cone chemically activated using ZnC12 and modified by HaPO4. Natural zeolite of clinoptilolite was with HC1, while nano-ceria modified by acid treatment was synthesized via redox method. Mixed supports of carbon-zeolite and carbon- ceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray emission scanning electron diffraction （XRD）, field microscopy （FESEM）, Brunauer-Emmett-Teller surface area （BET）, Fourier transform infrared spectroscopy （FTIR） and thermogravi- metric （TG） techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation ofnano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts （-1000 m^2·g^-1）. FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100℃-250℃. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds （VOCs）, represent- ing high catalytic performance of 98% for the abatement of xylene at 250℃. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocata- lysts.
