Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe（NO3）3.9H2O and Co（NO3）2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-（2,4-dichlorophen...Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe（NO3）3.9H2O and Co（NO3）2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-（2,4-dichlorophenoxy）propionic acid （2,4-DP）, nitrobenzene and oxalic acid. The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant, and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism. The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance. In the catalytic ozonation of 2,4-DP, the apparent reaction rate constants （k） were determined to be 1.456 × 10^-2 min-1 for ozonation alone and 4.740 × 10^-2 min^-1 for O3/Fe3O4-CoO/Al2O3. And O3/Fe3O4-CoO/Al2O3 had a larger Rot （6.614 × 10^-9） calculated by the relative method than O3 did （1.800 x 10-9）, showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical. Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid. The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.展开更多
Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good...Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al2O3 catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H2 pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg2Ni0.8Cr0.2 alloy surface was promoted by addition of CoO/Al2O3 catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg2Ni-based alloys.展开更多
基金supported by the National Natural Science Foundation of China(No.50578146,20876151)the National Science Foundation of Zhejiang Province,China(No.Y5080178)
文摘Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe（NO3）3.9H2O and Co（NO3）2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-（2,4-dichlorophenoxy）propionic acid （2,4-DP）, nitrobenzene and oxalic acid. The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant, and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism. The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance. In the catalytic ozonation of 2,4-DP, the apparent reaction rate constants （k） were determined to be 1.456 × 10^-2 min-1 for ozonation alone and 4.740 × 10^-2 min^-1 for O3/Fe3O4-CoO/Al2O3. And O3/Fe3O4-CoO/Al2O3 had a larger Rot （6.614 × 10^-9） calculated by the relative method than O3 did （1.800 x 10-9）, showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical. Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid. The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.
基金Project (No. TG20000264-06) supported by the Special Funds forMajor States Basic Research Project of MOST, China
文摘Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al2O3 catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H2 pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg2Ni0.8Cr0.2 alloy surface was promoted by addition of CoO/Al2O3 catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg2Ni-based alloys.
