Preparation And Wet Oxidation Performance Of The Multicomponent Loading Catalysts

In order to investigate the structure of the multicomponent catalysts and the performance of the refractory waste in catalytic wet air oxidation,using the ?-Al₂O₃ calcined by the pseudo-boehmite as the support,the transition metals,rare-earth metals and noble metals catalysts were used as the catalyst precursors in this paper,which prepared by the impregnation method.The fabric properties of the catalysts were characterized by different techniques:SEM,TEM,XRD,FT-IR,TG-DTA,and Nitrogen adsorption/desorption,and the catalysts were applied to the treatment of the methyl orange water sample,the actual ceramic printing wastewater,and the waste leachate.Research works mainly were as follows:?1?With copper nitrate and copper sulfate as the source of copper,the two Cu/?-Al2O3 catalyst were prepared by impregnation method,and the performance for treatment of the methyl orange water sample over the catalyst was surveyed,and the copper nitrate showed better catalytic performance.With the five kinds of nitrate for Cu,Fe,Co,Ce,and La as the source of metal,the corresponding single-component catalysts were prepared.The methyl orange water sample were treated in catalytic wet oxidation,the removal rate of metal salts was as follows:Cu?NO3?2>Fe?NO3?3>Co?NO3?3>La?NO3?3>Ce?NO3?4.The COD removal efficiency and decolorization rate of methyl orange methyl orange water sample over the copper nitrate were 72.5%and 88.5%,respectively,whereas the COD removal rate of water sample over Ce?NO3?4 and La?NO3?3 were 44.3%and 43.4%,respectively,which was in consistent with the COD removal rate of water sample over the support.The results indicated that the transition metal showed excellent catalytic performance,however the rare-earth metal catalytic efficiency exhibited lower catalytic performance.?2?The transition metal catalysts modified by the rare-earth were contributed to the improvement of the activity and stability for the catalyst.The catalysts modified by noble metals further improved the degradation performance of the water sample.By optimization experiment conditions,the calcined temperature and calcined time had a great influence on the experimental results.With the increase of calcined temperature and calcined time,the activity and stability of catalyst gradually reduced,and the metal leaching become small,at the same time the stability of the catalyst increased.The recycling performance and characterization of optimized conditions over the catalyst were investigated,which indicated that the recycling performance was excellent.?3?The kinetics for the CuFePdLa catalyst in catalytic wet air oxidation was analyzed,the dynamics model was ln?-?C/?t?=5.20/?RT?-13.87.?4?The COD and chromaticity of the ceramic printing wastewater over the catalyst Cu3Fe3/?-Al2O3 catalyst in catalytic wet air oxidation were 280 mg/L and 20 times,respectively,which reached the dye three level emission standard of the integrated wastewater discharge standard?GB8978-1996?in water sample,With the increase of precursor loading,the content of PtO2 and spinel CuAlO2 increased in the CuFePtLa catalyst;however,the improvement of the catalytic activity was unconspicuous.The catalyst with the loading 0.7 moljL had mesoporous structure,and the sample specific surface area and average pore diameter were 212.5 m2/g and 9.8 nm,respectively,and the catalyst components had uniform distribution on the surface,whose particle size was approximately 10-40 nm.The catalytic activity of CuFePtLa catalyst with the loading 0.7 mol/L in circular applications was well,and the XRD and FT-IR spectrum for the fresh and used catalysts had no obvious changes;therefore,the catalyst exhibited an excellent stability.