The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective depressants.In the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the...The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective depressants.In the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the pyrite surface to render the mineral surface hydrophilic and hinder the adsorption of the collector.This review summarizes the advances in depressants for the flotation separation of Cu–Fe sulfide minerals at low alkalinity.These advances include use of inorganic depressants (oxidants and sulfur–oxygen compounds),natural polysaccharides (starch,dextrin,konjac glucomannan,and galactomannan),modified polymers (carboxymethyl cellulose,polyacrylamide,lignosulfonate,and tricarboxylate sodium starch),organic acids (polyglutamic acid,sodium humate,tannic acid,pyrogallic acid,salicylic acid,and lactic acid),sodium dimethyl dithiocarbamate,and diethylenetriamine.The potential application of specific inorganic and organic depressants in the flotation separation of Cu–Fe sulfide minerals at low alkalinity is reviewed.The advances in the use of organic depressants with respect to the flotation separation of Cu–Fe sulfide minerals are comprehensively detailed.Additionally,the depression performances and mechanisms of different types of organic depressants on mineral surfaces are summarized.Finally,several perspectives on depressants vis-à-vis flotation separation of Cu–Fe sulfide minerals at low alkalinity are proposed.展开更多
The feasibility of a new method for separating arsenic from arsenic-antimony-bearing dusts using Cu S was put forward,in which Sb was transformed into Sb2O4 and Sb2S3 that stayed in the roasted calcine while As was vo...The feasibility of a new method for separating arsenic from arsenic-antimony-bearing dusts using Cu S was put forward,in which Sb was transformed into Sb2O4 and Sb2S3 that stayed in the roasted calcine while As was volatilized in the form of As4O6.The factors such as roasting temperature and Cu S addition amount were studied using XRD,EPMA and SEM-EDS.Cu S has an active effect on the separation of arsenic due to the destruction of(Sb,As)2 O3 structures in the original dust and the simultaneous release of As in the form of As4O6.At a roasting temperature of 400°C and Cu S addition amount of 130%,the volatilization rates of arsenic and antimony reach 97.80 wt.%and 8.29 wt.%,respectively.Further,the high As volatile matter can be used to prepare ferric arsenate after it is oxidized,with this treatment rendering the vapor harmlessness.展开更多
Converting solar energy into clean and sustainable chemical fuels is a promising strategy for exploiting renewable energy.The application of photocatalytic water splitting technology in hydrogen production is importan...Converting solar energy into clean and sustainable chemical fuels is a promising strategy for exploiting renewable energy.The application of photocatalytic water splitting technology in hydrogen production is important for sustainable energy development and environmental protection.In this study,for the first time,2D Cu7S4 co-catalysts were coupled on the surface of a CdS nanosheet photocatalyst by a one-step ultrasonic-assisted electrostatic self-assembly method at room temperature.The as-fabricated 2D^-2D CdS/Cu7S4 layered heterojunctions were demonstrated to be advanced composite photocatalysts that enhance the water splitting efficiency toward hydrogen production.The highest hydrogen evolution rate of the 2D^-2D CdS/2%Cu7S4 binary heterojunction photocatalyst was up to 27.8 mmol g^-1 h^-1 under visible light irradiation,with an apparent quantum efficiency of 14.7%at 420 nm,which was almost 10.69 times and 2.65 times higher than those of pure CdS nanosheets(2.6 mmol g^-1 h^-1)and CdS-2%CuS(10.5 mmol g^-1 h^-1),respectively.The establishment of the CdS/Cu7S4 binary-layered heterojunction could not only enhance the separation of photogenerated electron-hole(e--h+)pairs,improve the transfer of photo-excited electrons,and prolong the life-span of photo-generated electrons,but also enhance the light absorption and hydrogen-evolution kinetics.All these factors are important for the enhancement of the photocatalytic activity.Expectedly,the 2D^-2D interface coupling strategy based on CdS NSs can be extensively exploited to improve the hydrogen-evolution activity over various kinds of conventional semiconductor NSs.展开更多
The development of photocatalysts for hydrogen evolution is a promising alternative to industrial hydrogen evolution;however,generation of high active,recyclable,inexpensive heterojunctions are still challenging.Herei...The development of photocatalysts for hydrogen evolution is a promising alternative to industrial hydrogen evolution;however,generation of high active,recyclable,inexpensive heterojunctions are still challenging.Herein,a novel strategy was developed to synthesize non-noble metal co-catalyst/solid solution heterojunctions using metal-organic frameworks(MOFs)as a precursor template.By adjusting the content of MOFs,a series of Cu1.8S/ZnxCd1-xS heterojunctions were obtained,and the Cu1.8S(3.7%)/Zn0.35Cd0.65S sample exhibits a maximum hydrogen evolution rate of 14.27 mmol h^(-1) g^(-1) with an apparent quantum yield of 3.7%at 420 nm under visible-light irradiation.Subsequently,the relationship between the heterojunction and photocatalytic activity were investigated by detailed characterizations and density functional theory(DFT)calculations,which reveal that loading Cu1.8S can efficiently extend the light absorption,meanwhile,the electrons can efficiently transfer from Zn0.35Cd0.65S to Cu1.8S,thus resulting more photogenerated electrons participating in surface reactions.This result can be valuable inspirations for the exploitation of advanced materials using rationally designed nanostructures for solar energy conversion.展开更多
The coordination behavior of 2,3-butanedionemonoxime Girard’s T hydrazone (L<sup>1</sup>) towards Hg<sup>2+</sup> ion has been investigated. The structure of Hg<sup>2+</sup> comple...The coordination behavior of 2,3-butanedionemonoxime Girard’s T hydrazone (L<sup>1</sup>) towards Hg<sup>2+</sup> ion has been investigated. The structure of Hg<sup>2+</sup> complex, [Hg(L<sup>1</sup>)Cl]Cl·5H<sub>2</sub>O, is elucidated using elemental analyses, spectral (IR, UV-visible, 1H-NMR and mass) and TGA measurements. IR spectrum suggests that L<sup>1</sup> behaves in a bidentate manner through the azomethine groups. The molecular modeling of L<sup>1</sup> and its Hg<sup>2+</sup> complex has been investigated. The bond lengths, bond angles, HOMO and LUMO have been calculated. The thermal behavior and kinetic parameters are determined using Coats-Redfern method. The use of L<sup>1</sup> for preconcentration and separation via flotation of Hg<sup>2+</sup> complex and determination using cold vapor atomic spectrometry (CVAAS) is described. The effects on the percentage of recovered Hg<sup>2+</sup> by pH of sample solutions, oleic acid (HOL) concentration, Hg<sup>2+</sup> and L<sup>1</sup> concentrations are studied in details. The method is applied for the determination of the total Hg<sup>2+</sup> (mg·mL<sup>-1</sup>) in natural water samples.展开更多
基金financially supported by the Yunnan Major Scientific and Technological Projects,China (No.202202AG050015)the National Natural Science Foundation of China (No.51464029)。
文摘The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective depressants.In the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the pyrite surface to render the mineral surface hydrophilic and hinder the adsorption of the collector.This review summarizes the advances in depressants for the flotation separation of Cu–Fe sulfide minerals at low alkalinity.These advances include use of inorganic depressants (oxidants and sulfur–oxygen compounds),natural polysaccharides (starch,dextrin,konjac glucomannan,and galactomannan),modified polymers (carboxymethyl cellulose,polyacrylamide,lignosulfonate,and tricarboxylate sodium starch),organic acids (polyglutamic acid,sodium humate,tannic acid,pyrogallic acid,salicylic acid,and lactic acid),sodium dimethyl dithiocarbamate,and diethylenetriamine.The potential application of specific inorganic and organic depressants in the flotation separation of Cu–Fe sulfide minerals at low alkalinity is reviewed.The advances in the use of organic depressants with respect to the flotation separation of Cu–Fe sulfide minerals are comprehensively detailed.Additionally,the depression performances and mechanisms of different types of organic depressants on mineral surfaces are summarized.Finally,several perspectives on depressants vis-à-vis flotation separation of Cu–Fe sulfide minerals at low alkalinity are proposed.
基金Project(51564034)supported by the National Natural Science Foundation for Distinguished Regional Scholars,ChinaProject(2015HA019)supported by the Scientific and Technological Leading Talent Program in Yunnan Province,China.
文摘The feasibility of a new method for separating arsenic from arsenic-antimony-bearing dusts using Cu S was put forward,in which Sb was transformed into Sb2O4 and Sb2S3 that stayed in the roasted calcine while As was volatilized in the form of As4O6.The factors such as roasting temperature and Cu S addition amount were studied using XRD,EPMA and SEM-EDS.Cu S has an active effect on the separation of arsenic due to the destruction of(Sb,As)2 O3 structures in the original dust and the simultaneous release of As in the form of As4O6.At a roasting temperature of 400°C and Cu S addition amount of 130%,the volatilization rates of arsenic and antimony reach 97.80 wt.%and 8.29 wt.%,respectively.Further,the high As volatile matter can be used to prepare ferric arsenate after it is oxidized,with this treatment rendering the vapor harmlessness.
基金the National Natural Science Foundation of China(21975084,51672089)Special Funding on Applied Science and Technology in Guangdong(2017B020238005)+2 种基金the State Key Laboratory of Advanced Technology for Material Synthesis and Processing(Wuhan University of Technology)(2015-KF-7)State Scholarship Fund of China Scholarship Council(200808440114)the Ding Ying Talent Project of South China Agricultural University for their support
文摘Converting solar energy into clean and sustainable chemical fuels is a promising strategy for exploiting renewable energy.The application of photocatalytic water splitting technology in hydrogen production is important for sustainable energy development and environmental protection.In this study,for the first time,2D Cu7S4 co-catalysts were coupled on the surface of a CdS nanosheet photocatalyst by a one-step ultrasonic-assisted electrostatic self-assembly method at room temperature.The as-fabricated 2D^-2D CdS/Cu7S4 layered heterojunctions were demonstrated to be advanced composite photocatalysts that enhance the water splitting efficiency toward hydrogen production.The highest hydrogen evolution rate of the 2D^-2D CdS/2%Cu7S4 binary heterojunction photocatalyst was up to 27.8 mmol g^-1 h^-1 under visible light irradiation,with an apparent quantum efficiency of 14.7%at 420 nm,which was almost 10.69 times and 2.65 times higher than those of pure CdS nanosheets(2.6 mmol g^-1 h^-1)and CdS-2%CuS(10.5 mmol g^-1 h^-1),respectively.The establishment of the CdS/Cu7S4 binary-layered heterojunction could not only enhance the separation of photogenerated electron-hole(e--h+)pairs,improve the transfer of photo-excited electrons,and prolong the life-span of photo-generated electrons,but also enhance the light absorption and hydrogen-evolution kinetics.All these factors are important for the enhancement of the photocatalytic activity.Expectedly,the 2D^-2D interface coupling strategy based on CdS NSs can be extensively exploited to improve the hydrogen-evolution activity over various kinds of conventional semiconductor NSs.
基金the financially support by the National Natural Science Foundation of China as general projects(Nos.21722702 and 21874099)the Tianjin Commission of Science and Technology as key technologies R&D projects(Nos.18YFZCSF00730,18YFZCSF00770 and 18ZXSZSF00230)+1 种基金National Key Basic Research Program of China(No.2017YFA0403402)Science and Technology Research Projects of Colleges and Universities in Hebei province(No.ZD2020149)。
文摘The development of photocatalysts for hydrogen evolution is a promising alternative to industrial hydrogen evolution;however,generation of high active,recyclable,inexpensive heterojunctions are still challenging.Herein,a novel strategy was developed to synthesize non-noble metal co-catalyst/solid solution heterojunctions using metal-organic frameworks(MOFs)as a precursor template.By adjusting the content of MOFs,a series of Cu1.8S/ZnxCd1-xS heterojunctions were obtained,and the Cu1.8S(3.7%)/Zn0.35Cd0.65S sample exhibits a maximum hydrogen evolution rate of 14.27 mmol h^(-1) g^(-1) with an apparent quantum yield of 3.7%at 420 nm under visible-light irradiation.Subsequently,the relationship between the heterojunction and photocatalytic activity were investigated by detailed characterizations and density functional theory(DFT)calculations,which reveal that loading Cu1.8S can efficiently extend the light absorption,meanwhile,the electrons can efficiently transfer from Zn0.35Cd0.65S to Cu1.8S,thus resulting more photogenerated electrons participating in surface reactions.This result can be valuable inspirations for the exploitation of advanced materials using rationally designed nanostructures for solar energy conversion.
文摘The coordination behavior of 2,3-butanedionemonoxime Girard’s T hydrazone (L<sup>1</sup>) towards Hg<sup>2+</sup> ion has been investigated. The structure of Hg<sup>2+</sup> complex, [Hg(L<sup>1</sup>)Cl]Cl·5H<sub>2</sub>O, is elucidated using elemental analyses, spectral (IR, UV-visible, 1H-NMR and mass) and TGA measurements. IR spectrum suggests that L<sup>1</sup> behaves in a bidentate manner through the azomethine groups. The molecular modeling of L<sup>1</sup> and its Hg<sup>2+</sup> complex has been investigated. The bond lengths, bond angles, HOMO and LUMO have been calculated. The thermal behavior and kinetic parameters are determined using Coats-Redfern method. The use of L<sup>1</sup> for preconcentration and separation via flotation of Hg<sup>2+</sup> complex and determination using cold vapor atomic spectrometry (CVAAS) is described. The effects on the percentage of recovered Hg<sup>2+</sup> by pH of sample solutions, oleic acid (HOL) concentration, Hg<sup>2+</sup> and L<sup>1</sup> concentrations are studied in details. The method is applied for the determination of the total Hg<sup>2+</sup> (mg·mL<sup>-1</sup>) in natural water samples.
