The leaching performance and leaching kinetics of LiFePO_(4)(LFP)and Al in Al-bearing spent LFP cathode powder were systematically studied.The effects of temperature(273−368 K),stirring speed(200−950 r/min),reaction t...The leaching performance and leaching kinetics of LiFePO_(4)(LFP)and Al in Al-bearing spent LFP cathode powder were systematically studied.The effects of temperature(273−368 K),stirring speed(200−950 r/min),reaction time(0−240 min),acid-to-material ratio(0.1:1−1:1 mL/g)and liquid-to-solid ratio(3:1−9:1 mL/g)on the leaching process were investigated.The results show that the concentration of reactants and the temperature have a greater impact on the leaching of Al.Under the optimal conditions,leaching efficiencies of LFP and Al are 91.53%and 15.98%,respectively.The kinetic study shows that the leaching of LFP is kinetically controlled by mixed surface reaction and diffusion,with an activation energy of 22.990 kJ/mol;whereas the leaching of Al is only controlled by surface chemical reaction,with an activation energy of 46.581 kJ/mol.A low leaching temperature can effectively suppress the dissolving of Al during the acid leaching of the spent LFP cathode material.展开更多
To improve the adsorption performance and simplify uranium separation from aqueous media in post-treatment processes,a magnetic CoFe_(2)O_(4)@rGO composite was synthesized by microwave-hydrothermal method.The results ...To improve the adsorption performance and simplify uranium separation from aqueous media in post-treatment processes,a magnetic CoFe_(2)O_(4)@rGO composite was synthesized by microwave-hydrothermal method.The results of XRD,Raman,TEM/HRTEM,FTIR,BET and VSM characterization show that spinel-type cobalt ferrite CoFe_(2)O_(4) nanoparticles ca.13.4 nm in size are dispersedly anchored on the graphene sheet,and the saturation magnetization of the nanocomposite is 46.7 mA/(m^(2)·g).The effects of different pH,initial concentration and other conditions on uranium adsorption capacity were investigated,and adsorption kinetics equations were fitted to determine the adsorption behaviour of uranium on CoFe_(2)O_(4)@rGO in simulated uranium-containing seawater.It was observed that the uranium adsorption capacity of CoFe_(2)O_(4)@rGO composite at pH=5 is 127.6 mg/g,which is 1.31 and 2.43 times that of rGO and pure CoFe_(2)O_(4).The adsorption process conforms to Langmuir and quasi-second-order kinetic model.The excellent adsorption performance of CoFe_(2)O_(4)@rGO makes it potentially useful in the treatment of uranium-polluted water.展开更多
基金The authors acknowledge the funding support from the Key Deployment Projects of Chinese Academy of Sciences(ZDRW_CN_2020-1)the Sino-German Cooperation Research Project under the Natural Science Foundation of China(51761135108)+1 种基金the German Research Foundation(392417756)the CAS Interdisciplinary Innovation Team.
文摘The leaching performance and leaching kinetics of LiFePO_(4)(LFP)and Al in Al-bearing spent LFP cathode powder were systematically studied.The effects of temperature(273−368 K),stirring speed(200−950 r/min),reaction time(0−240 min),acid-to-material ratio(0.1:1−1:1 mL/g)and liquid-to-solid ratio(3:1−9:1 mL/g)on the leaching process were investigated.The results show that the concentration of reactants and the temperature have a greater impact on the leaching of Al.Under the optimal conditions,leaching efficiencies of LFP and Al are 91.53%and 15.98%,respectively.The kinetic study shows that the leaching of LFP is kinetically controlled by mixed surface reaction and diffusion,with an activation energy of 22.990 kJ/mol;whereas the leaching of Al is only controlled by surface chemical reaction,with an activation energy of 46.581 kJ/mol.A low leaching temperature can effectively suppress the dissolving of Al during the acid leaching of the spent LFP cathode material.
基金Project(19B126)supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(21772035)supported by the National Natural Science Foundation of China+1 种基金Projects(2018JJ3099,2019JJ40058)supported by the Provincial Natural Science Foundation of Hunan,ChinaProject supported by the Innovation and Entrepreneurship Training Program of Hunan Institute of Engineering,China。
文摘To improve the adsorption performance and simplify uranium separation from aqueous media in post-treatment processes,a magnetic CoFe_(2)O_(4)@rGO composite was synthesized by microwave-hydrothermal method.The results of XRD,Raman,TEM/HRTEM,FTIR,BET and VSM characterization show that spinel-type cobalt ferrite CoFe_(2)O_(4) nanoparticles ca.13.4 nm in size are dispersedly anchored on the graphene sheet,and the saturation magnetization of the nanocomposite is 46.7 mA/(m^(2)·g).The effects of different pH,initial concentration and other conditions on uranium adsorption capacity were investigated,and adsorption kinetics equations were fitted to determine the adsorption behaviour of uranium on CoFe_(2)O_(4)@rGO in simulated uranium-containing seawater.It was observed that the uranium adsorption capacity of CoFe_(2)O_(4)@rGO composite at pH=5 is 127.6 mg/g,which is 1.31 and 2.43 times that of rGO and pure CoFe_(2)O_(4).The adsorption process conforms to Langmuir and quasi-second-order kinetic model.The excellent adsorption performance of CoFe_(2)O_(4)@rGO makes it potentially useful in the treatment of uranium-polluted water.
