Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step,and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fent...Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step,and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fenton reagent.Then,the physical and chemical properties of the catalysts were analyzed by means of XRD,ICP-AES and SEM,especially the effect of Fe3O4 dispersity on γ-Al2O3.The results showed that the activity of the supported catalysts prepared with ultrasonic treatment for dimethoate was higher than those without ultrasonic treatment and the corresponding degradation rate doubled those of the catalyst obtained by impregnation.The probable cause was that for catalysts prepared with ultrasonic treatment,Fe3O4 was well dispersed on the catalyst surface with small particle size,or existed in non-crystalline amorphous state,and Fe content on the catalyst surface was higher than those without ultrasonic treatment.展开更多
The bimetallic catalyst Ru-Pt/ γ -Al 2O 3 was prepared by impregnating H 2PtCl 6 and RuCl 3 aqueous solution in the presence of PVP(40 000). Its catalytic performance in selective hydrogenation of \{ p -chloronitrobe...The bimetallic catalyst Ru-Pt/ γ -Al 2O 3 was prepared by impregnating H 2PtCl 6 and RuCl 3 aqueous solution in the presence of PVP(40 000). Its catalytic performance in selective hydrogenation of \{ p -chloronitrobenzene\}( p -CNB) was studied. The results indicate that the activity of Ru-Pt/ γ -Al 2O 3[\{ n (ruthenium)\}∶ n (platinum)=4∶1] is much higher than that of Ru/ γ -Al 2O 3,while the amount of dehalogenation product(aniline) and other by-products are much fewer than that by using Pt/ γ -Al 2O 3 as the catalyst. There is synergistic effect of ruthenium and platinum in bimetallic catalyst for selective hydrogenation of p -CNB. Under the reaction conditions t =50 ℃, p H 2 = 1.0 MPa, reaction time 60 min,\{ n (substrate)∶\} n (total amount of metal content)=1000∶1,the conversion of p -CNB and the selectivity to p -chloroaniline( p -CNA) by using Ru-Pt/ γ -Al 2O 3 as the catalyst are 48.2% and 85.9%,respectively. The effect of other metal cations(introduced to the reaction system with the corresponding metal chloride solution) on the reaction was investigated. It was found that catalytic performance of Ru-Pt/ γ -Al 2O 3 could be greatly improved by modfication of some metal cations. When Co 2+ and Ni 2+ were used as modifiers for the catalyst Ru-Pt/ γ -Al 2O 3 under above mentioned reaction conditions,the conversions of p -CNB increase to 74.5% and 87.8%,as well as the selectivities of p -CAN increase to 98.9% and 99.4%,respectively. Fe 3+ and Sn 4+ were the best modifiers for Ru-Pt/ γ -Al 2O 3 under the same reaction conditions. The conversions of p -CNB and the selectivities of p -CAN can reach 100% and >99.0%,respectively. However,the catalysts can be poisoned by Zn 2+ and Sn 2+ .展开更多
文摘Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step,and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fenton reagent.Then,the physical and chemical properties of the catalysts were analyzed by means of XRD,ICP-AES and SEM,especially the effect of Fe3O4 dispersity on γ-Al2O3.The results showed that the activity of the supported catalysts prepared with ultrasonic treatment for dimethoate was higher than those without ultrasonic treatment and the corresponding degradation rate doubled those of the catalyst obtained by impregnation.The probable cause was that for catalysts prepared with ultrasonic treatment,Fe3O4 was well dispersed on the catalyst surface with small particle size,or existed in non-crystalline amorphous state,and Fe content on the catalyst surface was higher than those without ultrasonic treatment.
文摘The bimetallic catalyst Ru-Pt/ γ -Al 2O 3 was prepared by impregnating H 2PtCl 6 and RuCl 3 aqueous solution in the presence of PVP(40 000). Its catalytic performance in selective hydrogenation of \{ p -chloronitrobenzene\}( p -CNB) was studied. The results indicate that the activity of Ru-Pt/ γ -Al 2O 3[\{ n (ruthenium)\}∶ n (platinum)=4∶1] is much higher than that of Ru/ γ -Al 2O 3,while the amount of dehalogenation product(aniline) and other by-products are much fewer than that by using Pt/ γ -Al 2O 3 as the catalyst. There is synergistic effect of ruthenium and platinum in bimetallic catalyst for selective hydrogenation of p -CNB. Under the reaction conditions t =50 ℃, p H 2 = 1.0 MPa, reaction time 60 min,\{ n (substrate)∶\} n (total amount of metal content)=1000∶1,the conversion of p -CNB and the selectivity to p -chloroaniline( p -CNA) by using Ru-Pt/ γ -Al 2O 3 as the catalyst are 48.2% and 85.9%,respectively. The effect of other metal cations(introduced to the reaction system with the corresponding metal chloride solution) on the reaction was investigated. It was found that catalytic performance of Ru-Pt/ γ -Al 2O 3 could be greatly improved by modfication of some metal cations. When Co 2+ and Ni 2+ were used as modifiers for the catalyst Ru-Pt/ γ -Al 2O 3 under above mentioned reaction conditions,the conversions of p -CNB increase to 74.5% and 87.8%,as well as the selectivities of p -CAN increase to 98.9% and 99.4%,respectively. Fe 3+ and Sn 4+ were the best modifiers for Ru-Pt/ γ -Al 2O 3 under the same reaction conditions. The conversions of p -CNB and the selectivities of p -CAN can reach 100% and >99.0%,respectively. However,the catalysts can be poisoned by Zn 2+ and Sn 2+ .
