A modified shrinking unreacted-core model,based on thermogravimetric analysis,was developed to investigate CaSO4 decomposition in oxy-fuel combustion,especially under isothermal condition which is difficult to achieve...A modified shrinking unreacted-core model,based on thermogravimetric analysis,was developed to investigate CaSO4 decomposition in oxy-fuel combustion,especially under isothermal condition which is difficult to achieve in actual experiments due to high-temperature corrosion.A method was proposed to calculate the reaction rate constant for CaSO4 decomposition.Meanwhile,the diffusion of SO2 and O2,and the sintering of CaO were fully considered during the development of model.The results indicate that the model can precisely predict the decomposition of CaSO4 under high SO2 concentration（1100×10-6）.Concentrations of SO2 and O2 on the unreacted-core surface were found to increase first and then decrease with increasing temperature,and the average specific surface area and porosity of each CaO sintering layer decreased with increasing time.The increase of SO2 and/or O2 concentration inhibited CaSO4 decomposition.Moreover,the kinetics of CaSO4 decomposition had obvious dependence on temperature and the decomposition rate can be dramatically accelerated with increasing temperature.展开更多
The heat recovery steam generator(HRSG)of copper smelting generates a large number of arsenic−coppercontaining particles,and the in-situ separation of arsenic and copper is of importance for cutting off environmental ...The heat recovery steam generator(HRSG)of copper smelting generates a large number of arsenic−coppercontaining particles,and the in-situ separation of arsenic and copper is of importance for cutting off environmental risk and realizing resource recovery.The formation of arsenic−copper-containing particles was simulated,the method of in-situ decomposition of arsenic−copper-containing particles by pyrite was proposed,and the decomposition mechanism was confirmed.It was found that particles with high arsenic content were formed in the simulated HRSG,and copper arsenate was liable for the high arsenic content.Pyrite promoted the sulfation of copper,leading to the in-situ decomposition of copper arsenate.In this process,gaseous arsenic was released,and thus the separation of arsenic and copper was realized.展开更多
Solar-driven water splitting is considered as a promising method to mitigate the energy crisis and various environmental issues.Bismuth vanadate(BiVO_(4))is photoanode material with tremendous potential for photoelect...Solar-driven water splitting is considered as a promising method to mitigate the energy crisis and various environmental issues.Bismuth vanadate(BiVO_(4))is photoanode material with tremendous potential for photoelectrochemical(PEC)water splitting.However,its PEC performance is severely hindered owing to poor surface charge transfer,surface recombination at the photoanode/electrolyte junction,and sluggish oxygen evolution reaction(OER)kinetics.In this regard,a novel solution was developed in this study to address these issues by decorating the surface of BiVO_(4)with cobalt sulfide,whose attractive features such as low cost,high conductivity,and rapid charge-transfer ability assisted in improving the PEC activity of the BiVO_(4)photoanode.The fabricated photoanode exhibited a significantly enhanced photocurrent density of 3.2 m A cm^(-2)under illumination at 1.23 V vs.a reversible hydrogen electrode,which is more than 2.5 times greater than that of pristine BiVO_(4).Moreover,the Co S/BiVO_(4)photoanode also exhibited considerable improvements in the charge injection yield(75.8%vs.36.7%for the bare BiVO_(4)film)and charge separation efficiency(79.8%vs.66.8%for the pristine BiVO_(4)film).These dramatic enhancements were primarily ascribed to rapid charge-transport kinetics and efficient reduction of the anodic overpotential for oxygen evolution enabled by the surface modification of BiVO_(4)by Co S.This study provides valuable suggestions for designing efficient photocatalysts via surface modification to improve the PEC performance.展开更多
基金Project(51276074)supported by the National Natural Science Foundation of ChinaProject(2014NY008)supported by Innovation Research Foundation of Huazhong University of Science and Technology,China
文摘A modified shrinking unreacted-core model,based on thermogravimetric analysis,was developed to investigate CaSO4 decomposition in oxy-fuel combustion,especially under isothermal condition which is difficult to achieve in actual experiments due to high-temperature corrosion.A method was proposed to calculate the reaction rate constant for CaSO4 decomposition.Meanwhile,the diffusion of SO2 and O2,and the sintering of CaO were fully considered during the development of model.The results indicate that the model can precisely predict the decomposition of CaSO4 under high SO2 concentration（1100×10-6）.Concentrations of SO2 and O2 on the unreacted-core surface were found to increase first and then decrease with increasing temperature,and the average specific surface area and porosity of each CaO sintering layer decreased with increasing time.The increase of SO2 and/or O2 concentration inhibited CaSO4 decomposition.Moreover,the kinetics of CaSO4 decomposition had obvious dependence on temperature and the decomposition rate can be dramatically accelerated with increasing temperature.
基金financially supported by the National Science Fund for Excellent Young Scholars of China(No.52022111)the National Key Research and Development Program of China(Nos.2017YFC0210401,2018YFC1900306)+1 种基金the Distinguished Young Scholars of China(No.51825403)the National Natural Science Foundation of China(Nos.51634010,51974379).
文摘The heat recovery steam generator(HRSG)of copper smelting generates a large number of arsenic−coppercontaining particles,and the in-situ separation of arsenic and copper is of importance for cutting off environmental risk and realizing resource recovery.The formation of arsenic−copper-containing particles was simulated,the method of in-situ decomposition of arsenic−copper-containing particles by pyrite was proposed,and the decomposition mechanism was confirmed.It was found that particles with high arsenic content were formed in the simulated HRSG,and copper arsenate was liable for the high arsenic content.Pyrite promoted the sulfation of copper,leading to the in-situ decomposition of copper arsenate.In this process,gaseous arsenic was released,and thus the separation of arsenic and copper was realized.
文摘Solar-driven water splitting is considered as a promising method to mitigate the energy crisis and various environmental issues.Bismuth vanadate(BiVO_(4))is photoanode material with tremendous potential for photoelectrochemical(PEC)water splitting.However,its PEC performance is severely hindered owing to poor surface charge transfer,surface recombination at the photoanode/electrolyte junction,and sluggish oxygen evolution reaction(OER)kinetics.In this regard,a novel solution was developed in this study to address these issues by decorating the surface of BiVO_(4)with cobalt sulfide,whose attractive features such as low cost,high conductivity,and rapid charge-transfer ability assisted in improving the PEC activity of the BiVO_(4)photoanode.The fabricated photoanode exhibited a significantly enhanced photocurrent density of 3.2 m A cm^(-2)under illumination at 1.23 V vs.a reversible hydrogen electrode,which is more than 2.5 times greater than that of pristine BiVO_(4).Moreover,the Co S/BiVO_(4)photoanode also exhibited considerable improvements in the charge injection yield(75.8%vs.36.7%for the bare BiVO_(4)film)and charge separation efficiency(79.8%vs.66.8%for the pristine BiVO_(4)film).These dramatic enhancements were primarily ascribed to rapid charge-transport kinetics and efficient reduction of the anodic overpotential for oxygen evolution enabled by the surface modification of BiVO_(4)by Co S.This study provides valuable suggestions for designing efficient photocatalysts via surface modification to improve the PEC performance.
