This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Diff...This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Different ratios of Ce(Ⅳ)were introduced into the iron oxide matrix,termed FeCe-5,FeCe-10,and FeCe-20.Their numerical values correspond to the nominal content of the dopant element added to the synthesis medium.The solid materials were characterized for morphology and chemical structure,and N_(2)physical adsorption/desorption measurements were performed.The solid materials doped with Ce(IV)have a high surface area compared to Fe_(3)O_(4),and the solid material with the highest content of the dopant ion(Ce(IV))has a 4-fold greater surface area.This increase in the dopant content in the iron oxide structure leads to a total chromium removal of 93.3%.Isotherms studies on the solid materials show that chromium adsorption follows the Langmuir model.The adsorption capacity to Fe_(3)O_(4)is 12.59 mg/g and FeCe-10 is 22.49 mg/g at 35℃.By fitting the kinetic and isothermal models,it is found that for the Fe_(3)O_(4)and FeCe-10 materials Cr(VI)removal occurs in very different ways,attributed to the different surface areas and compositions of the oxide,with the formation of the goethite(α-FeOOH)phase.The FeCe-10reuse process was performed and the removal capacity the Cr(VI)is reduced after the first cycle.This result is attributed to a strong and irreversible adsorption of Cr(VI)on the FeCe-10.展开更多
The methylene blue（MB）removal abilities of raw activated carbon and iron/cerium modified raw activated carbon（Fe–Ce-AC）by adsorption were researched and compared.The characteristics of Fe–Ce-AC were examined by ...The methylene blue（MB）removal abilities of raw activated carbon and iron/cerium modified raw activated carbon（Fe–Ce-AC）by adsorption were researched and compared.The characteristics of Fe–Ce-AC were examined by N2adsorption,zeta potential measurement,FTIR,Raman,XRD,XPS,SEM and EDS.After modification,the following phenomena occurred：The BET surface area,average pore diameter and total pore volume decreased;the degree of graphitization also decreased.Moreover,the presence of Fe3O4led to Fe–Ce-AC having magnetic properties,which makes it easy to separate from dye wastewater in an external magnetic field and subsequently recycle.In addition,the equilibrium isotherms and kinetics of MB adsorption on raw activated carbon and Fe–Ce-AC were systematically examined.The equilibrium adsorption data indicated that the adsorption behavior followed the Langmuir isotherm,and the pseudo-second-order model matched the kinetic data well.Compared with raw activated carbon,the maximum monolayer adsorption capacity of Fe–Ce-AC increased by27.31%.According to the experimental results,Fe–Ce-AC can be used as an effective adsorbent for the removal of MB from dye wastewater.展开更多
In this study, we used a simple impregnation method to prepare Fe-Ce-O<sub> x </sub> catalysts and tested them regarding their low-temperature (200-300 °C) selective catalytic reduction (SCR) of ...In this study, we used a simple impregnation method to prepare Fe-Ce-O<sub> x </sub> catalysts and tested them regarding their low-temperature (200-300 °C) selective catalytic reduction (SCR) of NO using NH<sub>3</sub>. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO<sub>2</sub>/H<sub>2</sub>O resistance of the catalysts. The results showed that the FeCe(1:6)O<sub> x </sub> (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O<sub> x </sub> catalyst had the highest NO conversion with an activity of 94-99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h<sup>−1</sup>. The NO conversion for the FeCe(1:6)O<sub> x </sub> catalyst also reached 80-98% between 200 and 300 °C at a space velocity of 204,000 h<sup>−1</sup>. In addition, the FeCe(1:6)O<sub> x </sub> catalyst demonstrated good stability in a 10-h SCR reaction at 200-300 °C. Even in the presence of SO<sub>2</sub> and H<sub>2</sub>O, the FeCe(1:6)O<sub> x </sub> catalyst exhibited good SCR performance.展开更多
Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically inves...Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.展开更多
基金the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)and Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)Programa de Pós-Graduacao em Agroquímica/UFLA(PPGAQ)+1 种基金Programa de Pós-Graduacao Multicêntrico em Química/UFLA(PPGMQ-MG)Centro de Prospeccao Química(CAPQ-UFLA)。
文摘This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Different ratios of Ce(Ⅳ)were introduced into the iron oxide matrix,termed FeCe-5,FeCe-10,and FeCe-20.Their numerical values correspond to the nominal content of the dopant element added to the synthesis medium.The solid materials were characterized for morphology and chemical structure,and N_(2)physical adsorption/desorption measurements were performed.The solid materials doped with Ce(IV)have a high surface area compared to Fe_(3)O_(4),and the solid material with the highest content of the dopant ion(Ce(IV))has a 4-fold greater surface area.This increase in the dopant content in the iron oxide structure leads to a total chromium removal of 93.3%.Isotherms studies on the solid materials show that chromium adsorption follows the Langmuir model.The adsorption capacity to Fe_(3)O_(4)is 12.59 mg/g and FeCe-10 is 22.49 mg/g at 35℃.By fitting the kinetic and isothermal models,it is found that for the Fe_(3)O_(4)and FeCe-10 materials Cr(VI)removal occurs in very different ways,attributed to the different surface areas and compositions of the oxide,with the formation of the goethite(α-FeOOH)phase.The FeCe-10reuse process was performed and the removal capacity the Cr(VI)is reduced after the first cycle.This result is attributed to a strong and irreversible adsorption of Cr(VI)on the FeCe-10.
基金the Specialized Research Fund for the National Natural Science Foundation of China (Nos.21567013, 51504119)the National High Technology Research and Development Program (863) of China (No. 2015AA020201)+1 种基金the Yunnan Applied Basic Research Project (No.2015FB129)the Yunnan Provincial Science and Technology Innovation Talents Scheme Technological Leading Talent (No.2013HA002)
文摘The methylene blue（MB）removal abilities of raw activated carbon and iron/cerium modified raw activated carbon（Fe–Ce-AC）by adsorption were researched and compared.The characteristics of Fe–Ce-AC were examined by N2adsorption,zeta potential measurement,FTIR,Raman,XRD,XPS,SEM and EDS.After modification,the following phenomena occurred：The BET surface area,average pore diameter and total pore volume decreased;the degree of graphitization also decreased.Moreover,the presence of Fe3O4led to Fe–Ce-AC having magnetic properties,which makes it easy to separate from dye wastewater in an external magnetic field and subsequently recycle.In addition,the equilibrium isotherms and kinetics of MB adsorption on raw activated carbon and Fe–Ce-AC were systematically examined.The equilibrium adsorption data indicated that the adsorption behavior followed the Langmuir isotherm,and the pseudo-second-order model matched the kinetic data well.Compared with raw activated carbon,the maximum monolayer adsorption capacity of Fe–Ce-AC increased by27.31%.According to the experimental results,Fe–Ce-AC can be used as an effective adsorbent for the removal of MB from dye wastewater.
基金supported by the National Natural Science Foundation of China (No.21206108)Tianjin Municipal Science and Technology Commission (No.14JCYBJC21200)
文摘In this study, we used a simple impregnation method to prepare Fe-Ce-O<sub> x </sub> catalysts and tested them regarding their low-temperature (200-300 °C) selective catalytic reduction (SCR) of NO using NH<sub>3</sub>. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO<sub>2</sub>/H<sub>2</sub>O resistance of the catalysts. The results showed that the FeCe(1:6)O<sub> x </sub> (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O<sub> x </sub> catalyst had the highest NO conversion with an activity of 94-99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h<sup>−1</sup>. The NO conversion for the FeCe(1:6)O<sub> x </sub> catalyst also reached 80-98% between 200 and 300 °C at a space velocity of 204,000 h<sup>−1</sup>. In addition, the FeCe(1:6)O<sub> x </sub> catalyst demonstrated good stability in a 10-h SCR reaction at 200-300 °C. Even in the presence of SO<sub>2</sub> and H<sub>2</sub>O, the FeCe(1:6)O<sub> x </sub> catalyst exhibited good SCR performance.
基金financially supported by the National Natural Science Foundation of China(No.52174363)the GDAS Project of Science and Technology Development,China(No.2019GDASYL-0203002)+2 种基金the Key Research and Development Program of Guangdong Province,China(No.2020B010186002)the Science and Technology Project of Zhaoqing City,China(Nos.2021C003,2018K006)the Development of Key Technologies for Material and Microstructure Control of High Thermal Conductivity Casting Aluminum Alloy,China(No.2014A030313221)。
文摘Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.
