Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The tol...Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The toluene adsorption capacities of the regeneration AC(RAC)samples can be significantly improved by adopting the heteroatomic modification strategy.RAC-P and RAC-S have the same specific surface area(1156 m^(2)/g)and similar porous structures.However,they have different toluene adsorption capacities,with 316.22 mg/g for RAC-P and 460.12 mg/g for RAC-S,which are 1.6 and 2.4 times greater than that for RAC.The X-ray photoelectron spectroscopy measurements showed that the increase in the amount ofπ–π^(2)chemical bond over the AC surface results in the improvement of the toluene adsorption performance.The density functional theory results showed that the S-containing functional groups loaded near the defect sites of RAC-S promote toluene adsorption.Moreover,reusability tests showed that RAC-S still retains 86%of its adsorption activity after four consecutive adsorption–desorption experiments.This indicates that the heteroatomic modification method affords excellent toluene adsorption performance and recycling practicability,which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of volatile organic compounds.展开更多
研究了寄生电感对基于常通型碳化硅(silicon carbide,SiC)结型场效应晶体管(junction field effect transistor,JFET)串联结构的中压直流固态断路器(solid state circuit breaker,SSCB)过电压的影响,并在此基础上提出了一种SSCB的过电...研究了寄生电感对基于常通型碳化硅(silicon carbide,SiC)结型场效应晶体管(junction field effect transistor,JFET)串联结构的中压直流固态断路器(solid state circuit breaker,SSCB)过电压的影响,并在此基础上提出了一种SSCB的过电压抑制方法。首先介绍了基于常通型SiC JFET器件串联结构的SSCB拓扑及工作原理,建立了考虑完整回路寄生电感的SiC JFET串联结构开关过程的数学模型。其次利用MATLAB软件对数学模型进行解析计算,揭示了SSCB开关过程中寄生电感对SiC JFET器件串联运行时过电压的影响机理,并利用PSPICE仿真结果验证了理论分析的正确性。最后设计了一种适用于SSCB过电压抑制的单栅极驱动及缓冲电路,并通过SSCB实验样机验证了所提方法的有效性。展开更多
Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were f...Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were further modified by potassium ferrate to finally prepare high-performance carbon for VOCs adsorption.At the same time,the samples before and after modification were systematically studied through characterization techniques such as SEM,Raman spectrometry,FT-IR,XPS,and dynamic/static adsorption.The results showed that the specific surface area and pore volume of the RAC after modification by the strong oxidant potassium ferrate increased by 1.4 times;the degree of defects was enhanced and the content of oxygen-containing functional groups on the surface increased significantly.Among them,the sample modified with potassium ferrate for 24 h had the best dynamic toluene adsorption performance(375.5 mg/g),and the dynamic adsorption capacity was twice that of the original sample(192.8 mg/g).The static adsorption test found that the maximum adsorption capacity of RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h was 796 mg/g,which indicated that the potassium ferrate modification treatment could significantly increase the VOCs adsorption performance of RAC.In addition,through consecutive toluene adsorption-desorption cycle tests,it was found that the RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h sample still retained 91%of adsorption activity after the fifth regeneration cycle.This indicates that RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h has good cycle stability and great application value for the efficient purification of industrial waste VOCs gas.展开更多
基金National key R&D Program of China(No.2022YFC3701903)natural science foundation of Shanxi Province(No.202203021211178)National Natural Science Foundation of China(51901209)for financial support.
文摘Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The toluene adsorption capacities of the regeneration AC(RAC)samples can be significantly improved by adopting the heteroatomic modification strategy.RAC-P and RAC-S have the same specific surface area(1156 m^(2)/g)and similar porous structures.However,they have different toluene adsorption capacities,with 316.22 mg/g for RAC-P and 460.12 mg/g for RAC-S,which are 1.6 and 2.4 times greater than that for RAC.The X-ray photoelectron spectroscopy measurements showed that the increase in the amount ofπ–π^(2)chemical bond over the AC surface results in the improvement of the toluene adsorption performance.The density functional theory results showed that the S-containing functional groups loaded near the defect sites of RAC-S promote toluene adsorption.Moreover,reusability tests showed that RAC-S still retains 86%of its adsorption activity after four consecutive adsorption–desorption experiments.This indicates that the heteroatomic modification method affords excellent toluene adsorption performance and recycling practicability,which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of volatile organic compounds.
基金financialy supported by the National Natural Science Foundation of China (No.21936005,52070114,21876093)the Postdoctoral Science Program of China (No.2019M660061)
文摘Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were further modified by potassium ferrate to finally prepare high-performance carbon for VOCs adsorption.At the same time,the samples before and after modification were systematically studied through characterization techniques such as SEM,Raman spectrometry,FT-IR,XPS,and dynamic/static adsorption.The results showed that the specific surface area and pore volume of the RAC after modification by the strong oxidant potassium ferrate increased by 1.4 times;the degree of defects was enhanced and the content of oxygen-containing functional groups on the surface increased significantly.Among them,the sample modified with potassium ferrate for 24 h had the best dynamic toluene adsorption performance(375.5 mg/g),and the dynamic adsorption capacity was twice that of the original sample(192.8 mg/g).The static adsorption test found that the maximum adsorption capacity of RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h was 796 mg/g,which indicated that the potassium ferrate modification treatment could significantly increase the VOCs adsorption performance of RAC.In addition,through consecutive toluene adsorption-desorption cycle tests,it was found that the RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h sample still retained 91%of adsorption activity after the fifth regeneration cycle.This indicates that RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h has good cycle stability and great application value for the efficient purification of industrial waste VOCs gas.
