Attrition resistance in an adsorbent is one measure of its mechanical strength.It quantifies its ability to resist the impact of frictional forces generated in a milieu where hydrodynamic agitation exists.However,attr...Attrition resistance in an adsorbent is one measure of its mechanical strength.It quantifies its ability to resist the impact of frictional forces generated in a milieu where hydrodynamic agitation exists.However,attrition resistance has been only sporadically examined in adsorbents used to remove aqueous adsor-bates.Since attrition is relevant in aqueous adsorption process design,this review discusses the quan-tification of attrition resistance,variability in loss due to attrition across adsorbents,and the implications of attrition on adsorption systems.Finally,some key research opportunities that could be explored for a better understanding of attrition in real-scale water purification are presented.It is inferred that sub-stantial research and development still needs to be accomplished to better understand the attrition resistance-adsorbent behavior within real-scale aqueous adsorption environments.The results can be harnessed to design and produce more robust,efficient and cost-effective adsorbents.展开更多
Fluidized-bed reactor is a candidate for dimethyl ether （DME） synthesis from syngas because of its excellent heat removal capability. In order to improve the attrition resistance of catalyst, an amount of silica sol...Fluidized-bed reactor is a candidate for dimethyl ether （DME） synthesis from syngas because of its excellent heat removal capability. In order to improve the attrition resistance of catalyst, an amount of silica sol as binder was added to the catalyst composed of methanol synthesis component CuO/ZnO/Al2O3 and methanol dehydration component HZSM-5, which was prepared by coprecipitation and shaped by spray drying to get spherical particles. The effect of silica sol on the catalytic activity was investigated in a fixed-bed flow microreactor. Based on the experiment results, silica sol in the range of 0-20wt% had small effect on the catalytic activity. Generally, the CO conversion and DME yield decreased with the increase in concentration of silica sol, while the attrition resistance of catalysts increased with increasing silica sol, indicating that it was feasible to improve the attrition resistance without greatly sacrificing the activity of catalyst. In addition, the characterizations of catalysts were carried out using Brunauer-Emmett-Teller （BET）, X-ray powder diffraction （XRD） and temperature programmed reduction （TPR）.展开更多
Ni-P-SiC composite coatings were electroplated on carbon steel substrate assisted by mechanical attrition （MA）. The MA action was conducted by dispersing glass balls on the cathodic surface, vibrating in the horizon...Ni-P-SiC composite coatings were electroplated on carbon steel substrate assisted by mechanical attrition （MA）. The MA action was conducted by dispersing glass balls on the cathodic surface, vibrating in the horizontal direction. The experimental results show that, under the assistant of MA action, the adhesion of Ni-P-SiC coating on the steel substrate can be improved effectively, and the Ni-P-SiC coatings exhibit a crystallized structure and Ni-P matrix can combine tightly with SiC particles, and the hardness and corrosion resistance of these coatings increase markedly. During heat treatment, the defects produced in conventional Ni-P-SiC composite coatings can be avoided assisted by MA action. Both of the wear of these coatings can be improved further.展开更多
文摘Attrition resistance in an adsorbent is one measure of its mechanical strength.It quantifies its ability to resist the impact of frictional forces generated in a milieu where hydrodynamic agitation exists.However,attrition resistance has been only sporadically examined in adsorbents used to remove aqueous adsor-bates.Since attrition is relevant in aqueous adsorption process design,this review discusses the quan-tification of attrition resistance,variability in loss due to attrition across adsorbents,and the implications of attrition on adsorption systems.Finally,some key research opportunities that could be explored for a better understanding of attrition in real-scale water purification are presented.It is inferred that sub-stantial research and development still needs to be accomplished to better understand the attrition resistance-adsorbent behavior within real-scale aqueous adsorption environments.The results can be harnessed to design and produce more robust,efficient and cost-effective adsorbents.
文摘Fluidized-bed reactor is a candidate for dimethyl ether （DME） synthesis from syngas because of its excellent heat removal capability. In order to improve the attrition resistance of catalyst, an amount of silica sol as binder was added to the catalyst composed of methanol synthesis component CuO/ZnO/Al2O3 and methanol dehydration component HZSM-5, which was prepared by coprecipitation and shaped by spray drying to get spherical particles. The effect of silica sol on the catalytic activity was investigated in a fixed-bed flow microreactor. Based on the experiment results, silica sol in the range of 0-20wt% had small effect on the catalytic activity. Generally, the CO conversion and DME yield decreased with the increase in concentration of silica sol, while the attrition resistance of catalysts increased with increasing silica sol, indicating that it was feasible to improve the attrition resistance without greatly sacrificing the activity of catalyst. In addition, the characterizations of catalysts were carried out using Brunauer-Emmett-Teller （BET）, X-ray powder diffraction （XRD） and temperature programmed reduction （TPR）.
基金supported by the National Natural Science Foundation of China (No.50671006)
文摘Ni-P-SiC composite coatings were electroplated on carbon steel substrate assisted by mechanical attrition （MA）. The MA action was conducted by dispersing glass balls on the cathodic surface, vibrating in the horizontal direction. The experimental results show that, under the assistant of MA action, the adhesion of Ni-P-SiC coating on the steel substrate can be improved effectively, and the Ni-P-SiC coatings exhibit a crystallized structure and Ni-P matrix can combine tightly with SiC particles, and the hardness and corrosion resistance of these coatings increase markedly. During heat treatment, the defects produced in conventional Ni-P-SiC composite coatings can be avoided assisted by MA action. Both of the wear of these coatings can be improved further.
