Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal ga...Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal gangue were investigated by X-ray diffraction. Moreover, the acid leaching kinetics of aluminum oxide from coal gangue was investigated with sulfuric acid. It showed that the air atmosphere promoted kaolinite decomposition during coal gangue calcination. The hydrogen atmosphere promoted the activation and decomposition of kaolinite at reaction temperatures exceeding 650℃. The carbon dioxide atmosphere eliminated the influence of residual carbon on coal gangue. When the ratio of acid/coal gangue was 1.5 and reaction temperature was 650℃, the sulfuric acid leaching rate under air, air-hydrogen, carbon dioxide, hydrogen and nitrogen atmospheres were 93.66%, 90.90%, 84.06%, 81.91% and 77.54% respectively. The acid leaching reaction process conformed to unreacted shrinking core model of particle unchanged, and was controlled by the interracial chemical reaction. The reaction kinetic equation for the leaching process was 1-（1-x）1/3=kt with an apparent activation energy of 48.97 kJ/mol.展开更多
Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The ...Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H_(2)O to CO_(2)in the activation atmosphere.The theoretical validation was conducted through density functional calculations.The two gas molecules follow different pathways to increase the reactivity of char.CO_(2)mainly participates in the cross-linking reaction by intensifying branching,while H_(2)O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional groups.Gas molecules partially compete for active sites in a mixed gas atmosphere,but there is a synergism between the two effects.The synergism can be attributed to two possibilities.The inclusion of H_(2)O mitigates the generation of five-membered rings to a limited extent,while concurrently enhances the development of oxygen-containing functional groups.Introducing oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char,consequently leading to a reduction in the energy demand for subsequent bond cleavage.展开更多
In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction m...In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.展开更多
The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company.The company produced thin silver metallic films and the production scraps were silver fl...The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company.The company produced thin silver metallic films and the production scraps were silver flakes.The possibility to use the silver flakes in water disinfection processes was studied.The antimicrobial activity of the flakes was investigated in batch using Escherichia coli as Gram-negative microorganism model.The flakes did not show any antimicrobial activity,so they were activated with two different processes： thermal activation in reducing atmosphere and chemical activation,obtaining,respectively,reduced flakes （RF） and chemical flakes （CF）.The flakes,activated with either treatment,showed antimicrobial activity against E.coli.The kill rate was dependent on the type of activated flakes.The chemical flakes were more efficient than reduced flakes.The kill rate determined for 1 g of CF,1.0 ± 0.2 min ？1 ,was greater than the kill rate determined for 1 g of RF,0.069 ± 0.004 min ？1 .This was confirmed also by the minimum inhibitory concentration values.It was demonstrated that the antimicrobial capability was dependent on flakes amount and on the type of aqueous medium.Furthermore,the flakes maintained their properties also when used a second time.Finally,the antimicrobial activities of flakes were tested in an effluent of a wastewater treatment plant where a variety of heterotrophic bacteria were present.展开更多
基金supported by National Natural Science Foundation of China(51074170)Shaanxi Key Technology R&D Program(2016GY-147)+1 种基金Key Laboratory of Coal Resources Exploration and Comprehensive UtilizationMinistry of Land and Resources Open Research Topic(KF2016-3)
文摘Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal gangue were investigated by X-ray diffraction. Moreover, the acid leaching kinetics of aluminum oxide from coal gangue was investigated with sulfuric acid. It showed that the air atmosphere promoted kaolinite decomposition during coal gangue calcination. The hydrogen atmosphere promoted the activation and decomposition of kaolinite at reaction temperatures exceeding 650℃. The carbon dioxide atmosphere eliminated the influence of residual carbon on coal gangue. When the ratio of acid/coal gangue was 1.5 and reaction temperature was 650℃, the sulfuric acid leaching rate under air, air-hydrogen, carbon dioxide, hydrogen and nitrogen atmospheres were 93.66%, 90.90%, 84.06%, 81.91% and 77.54% respectively. The acid leaching reaction process conformed to unreacted shrinking core model of particle unchanged, and was controlled by the interracial chemical reaction. The reaction kinetic equation for the leaching process was 1-（1-x）1/3=kt with an apparent activation energy of 48.97 kJ/mol.
基金supported by the CAS Project for Young Scientists in Basic Research(YSBR-028)。
文摘Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H_(2)O to CO_(2)in the activation atmosphere.The theoretical validation was conducted through density functional calculations.The two gas molecules follow different pathways to increase the reactivity of char.CO_(2)mainly participates in the cross-linking reaction by intensifying branching,while H_(2)O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional groups.Gas molecules partially compete for active sites in a mixed gas atmosphere,but there is a synergism between the two effects.The synergism can be attributed to two possibilities.The inclusion of H_(2)O mitigates the generation of five-membered rings to a limited extent,while concurrently enhances the development of oxygen-containing functional groups.Introducing oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char,consequently leading to a reduction in the energy demand for subsequent bond cleavage.
基金supported by the Qingdao Postdoctoral Program Funding(QDBSH20220202045)Shandong provincial Natural Science Foundation(ZR2021ME049,ZR2022ME176)+1 种基金National Natural Science Foundation of China(22078176)Taishan Industrial Experts Program(TSCX202306135).
文摘In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.
基金Lombardia Region for financial support (Progetto Ingenio)
文摘The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company.The company produced thin silver metallic films and the production scraps were silver flakes.The possibility to use the silver flakes in water disinfection processes was studied.The antimicrobial activity of the flakes was investigated in batch using Escherichia coli as Gram-negative microorganism model.The flakes did not show any antimicrobial activity,so they were activated with two different processes： thermal activation in reducing atmosphere and chemical activation,obtaining,respectively,reduced flakes （RF） and chemical flakes （CF）.The flakes,activated with either treatment,showed antimicrobial activity against E.coli.The kill rate was dependent on the type of activated flakes.The chemical flakes were more efficient than reduced flakes.The kill rate determined for 1 g of CF,1.0 ± 0.2 min ？1 ,was greater than the kill rate determined for 1 g of RF,0.069 ± 0.004 min ？1 .This was confirmed also by the minimum inhibitory concentration values.It was demonstrated that the antimicrobial capability was dependent on flakes amount and on the type of aqueous medium.Furthermore,the flakes maintained their properties also when used a second time.Finally,the antimicrobial activities of flakes were tested in an effluent of a wastewater treatment plant where a variety of heterotrophic bacteria were present.
基金Supported by the National Natural Science Foundation of China(U1361125,U1261208,21176001,51174254)the Provincial Innovative Group for Processing&Clean Utilization of Coal Resourcethe Innovative Research Team of Anhui University of Technology
