The oxidation characteristics of sulfite and thiosulfate were examined by using thermodynamic calculations and simulated desulfurization solution experiments to investigate their difference.Subsequently,a new multista...The oxidation characteristics of sulfite and thiosulfate were examined by using thermodynamic calculations and simulated desulfurization solution experiments to investigate their difference.Subsequently,a new multistage oxidation method using oxygen−ammonium persulfate was presented and applied to the oxidation of a real desulfurization solution.The results show that the concentrations of thiosulfate and sulfite in the real desulfurization solution decrease from 48.76 and 61.76 g/L to 2.24 and 0.02 g/L,respectively,and the ammonium sulfate products obtained are white with uniform particles.In addition,compared with ammonium persulfate alone,the multistage oxidation method can reduce the ammonium persulfate addition by 37.56%and treatment cost by 28.13%.展开更多
This study addresses the global problem of the detoxification of cadmium(Cd)-containing solid waste by developing an eco-friendly thiosulfate system for extracting the negative electrode materials from spent Ni–Cd ba...This study addresses the global problem of the detoxification of cadmium(Cd)-containing solid waste by developing an eco-friendly thiosulfate system for extracting the negative electrode materials from spent Ni–Cd batteries and proposing an ultraviolet(UV)photolysis technology for the green recycling of the Cd in the resultant leached solution.Cd extraction is performed using both simple thiosulfate and cuprous thiosulfate systems,with the cuprous thiosulfate system exhibiting a superior leaching performance(80%),as compared with that of the simple thiosulfate system(36%).X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)analyses reveal the formation of copper sulfide on the surface of the Ni–Cd batteries leaching residue,which is confirmed by Cdleaching kinetics fitting using the shrinking-core model.Following UV exposure,95%of the Cd precipitates from the leaching solution to form CdS.Transmission electron microscopy(TEM)characterization and particle size distribution reveal that the CdS contains 100–150 nm-diameter spherical particles with compact surface structures.Electrochemical performance tests and UV–visible diffuse reflectance spectra(UV–Vis DRS)analyses demonstrate that the UV-photolysis product exhibits excellent photoelectric conversion characteristics.Photocatalytic activity tests of the recovered CdS confirm that the photocatalytic degradation ratio of methyl orange is 87%,indicating the successful green recycling of Cd from spent Ni–Cd batteries,which improves its potential application in the field of photocatalysis.展开更多
The adsorption behaviors and mechanisms of gold from thiosulfate solution on strong-base anion exchange resin were systematically investigated.The comparison experiment of adsorption ability and selectivity for gold s...The adsorption behaviors and mechanisms of gold from thiosulfate solution on strong-base anion exchange resin were systematically investigated.The comparison experiment of adsorption ability and selectivity for gold showed that gel Amberlite IRA-400 resin with Type Ⅰ quaternary ammonium functional group had better adsorption performance.The increases of resin dosage,ammonia concentration and solution pH were favorable to gold adsorption,whereas the rises of cupric and thiosulfate concentrations were disadvantageous to gold loading.Microscopic characterization results indicated that gold was adsorbed in the form of [Au(S_(2)O_(3))_(2)]^(3–) complex anion by exchanging with the counter ion Cl^(–) in the functional group of the resin.Density functional theory calculation result manifested that gold adsorption was mainly depended on the hydrogen bond and van der Waals force generated between O atom in [Au(S_(2)O_(3))_(2)]^(3–) and H atom in the quaternary ammonium functional group of the resin.展开更多
The genus Marinobacter is very broadly distributed in global environments and is considered as aerobic heterotroph.In this study,six Marinobacter strains were identified with autotrophic thiosulfate oxidation capacity...The genus Marinobacter is very broadly distributed in global environments and is considered as aerobic heterotroph.In this study,six Marinobacter strains were identified with autotrophic thiosulfate oxidation capacity.These strains,namely Marinobacter guineae M3B^(T),Marinobacter aromaticivorans D15-8PT,Marinobacter vulgaris F01^(T),Marinobacter profundi PWS21^(T),Marinobacter denitrificans JB02H27T,and Marinobacter sp.ST-1M(with a 99.93%similarity to the 16S rDNA sequences of Marinobacter salsuginis SD-14B^(T)),were screened out of 32 Marinobacter strains by autotrophic thiosulfate oxidization medium.The population of cells grew in a chemolithotrophic medium,increasing from 105 cells/mL to 10^(7) cells/mL within 5 d.This growth was accompanied by the consumption of thiosulfate 3.59 mmol/L to 9.64 mmol/L and the accumulation of sulfate up to 0.96 mmol/L,and occasionally produced sulfur containing complex particles.Among these Marinobacter strains,it was also found their capability of oxidizing thiosulfate to sulfate in a heterotrophic medium.Notably,M.vulgaris F01^(T)and M.antarcticus ZS2-30^(T)showed highly significant production of sulfate at 9.45 mmol/L and 3.10 mmol/L.Genome annotation indicated that these Marinobacter strains possess a complete Sox cluster for thiosulfate oxidation.Further phylogenetic analysis of the soxB gene revealed that six Marinobacter strains formed a separate lineage within Gammaproteobacteria and close to obligate chemolithoautotroph Thiomicrorhabdus arctica.The results indicated that thiosulfate oxidizing and chemolithoautotrophic potential in Marinobacter genus,which may contribute to the widespread of Marinobacter in the global ocean.展开更多
Carbon supported Pt-based intermetallic compounds(IMCs)with high activity and durability are the most competitive cathode catalysts for the commercialization of proton exchange membrane fuel cells(PEMFCs).The synthesi...Carbon supported Pt-based intermetallic compounds(IMCs)with high activity and durability are the most competitive cathode catalysts for the commercialization of proton exchange membrane fuel cells(PEMFCs).The synthesis of Pt-based intermetallics with a good balance between small size and high metal loading remains challenging because of the high-temperature annealing that is generally required to form intermetallic phases.We developed a sodium thiosulfate-assisted impregnation strategy to synthesize small-sized and highly ordered PtM IMCs catalysts(M=Co,Fe,Ni)with high-Pt-content(up to 44.5 wt%).During the impregnation process,thiosulfate could reduce H_(2)PtCl6 to form uniformly dispersed Pt colloid on carbon supports,which in turn prevents the aggregation of Pt at the low-temperature annealing stage.Additionally,the strong interaction between Pt and S inhibits particle sintering,ensuring the formation of small-sized and uniform PtM intermetallic catalysts at the high-temperature annealing stage.The optimized intermetallic PtCo catalyst delivered a high mass activity of 0.72 A mgPt^(–1)and a large power performance of 1.17 W·cm^(–2)at 0.65 V under H_(2)-air conditions,along with 74%mass activity retention after the accelerated stress test.展开更多
Cyanide-free silver electroplating was conducted in thiosulfate baths containing AgNO3 and AgBr major salts, respectively. The effects of major salt content and current density on surface quality, deposition rate and ...Cyanide-free silver electroplating was conducted in thiosulfate baths containing AgNO3 and AgBr major salts, respectively. The effects of major salt content and current density on surface quality, deposition rate and microhardness of Ag coatings were investigated. The optimized electroplating parameters were established. The adhesion strength of Ag coating on Cu substrate was evaluated and the grain size of Ag coating was measured under optimized electroplating parameters. The optimized AgNO3 content is 40 g/L with current density of 0.25 A/dm2. The deposited bright, smooth, and well adhered Ag coating had nanocrystalline grains with mean size of 35 nm. The optimized AgBr content was 30 g/L with current density of 0.20 A/dm2. The resultant Ag coating had nanocrystalline grains with mean size of 55 nm. Compared with the bath containing AgBr main salt, the bath containing AgNO3 main salt had a wider current density range, and corresponding Ag coating had a higher microhardness and a smaller grain size.展开更多
Arsenopyrite was artificially added into the thiosulfate leaching solution to clarify the role of arsenopyrite on the thiosulfate leaching of gold.The effect of arsenopyrite on the thiosulfate leaching of gold was stu...Arsenopyrite was artificially added into the thiosulfate leaching solution to clarify the role of arsenopyrite on the thiosulfate leaching of gold.The effect of arsenopyrite on the thiosulfate leaching of gold was studied by the thermodynamic calculation,mineral dissolution test,leaching test and XPS analysis.The results show that the thiosulfate consumption slightly increases with increasing the concentration of arsenopyrite,but the gold dissolution is obviously hindered.This may mainly attribute to the catalytic effect of arsenopyrite on the thiosulfate decomposition and the formation of passivation layer on the gold foil surface.The passivation layer likely consists of Cu2S or Cu（S2O3）35-,element S,FeOOH and iron arsenate,which is deduced from the XPS analysis.However,the negative effect of arsenopyrite can be eliminated by adding additives.It is found that both additives of sodium carboxymethyl（CMC） and sodium phosphate（SHPP） can not only decrease the thiosulfate consumption but also improve the gold dissolution.展开更多
Numerous non-cyanide leaching lixiviants have been developed,among which thiosulfate is considered the most promising alternative to cyanide due to its non-toxicity,low price,high leaching rate and excellent character...Numerous non-cyanide leaching lixiviants have been developed,among which thiosulfate is considered the most promising alternative to cyanide due to its non-toxicity,low price,high leaching rate and excellent characteristics in dealing with carbonaceous and copper-bearing gold ores.The traditional copper−ammonia−thiosulfate system has been studied extensively.However,with many years of process development,there are still some problems and challenges with this gold leaching system.A series of studies using nickel-,cobalt-and ferric-based catalyst to substitute copper have been conducted with the purpose of reducing the consumption of thiosulfate.A variety of non-ammonia thiosulfate leaching systems including oxygen−thiosulfate,copper−thiosulfate,copper−EDA−thiosulfate,ferric−EDTA−thiosulfate,and ferric−oxalate−thiosulfate leaching systems have been also developed to eliminate the potential side-effect of ammonia.In this review,the basic theory and process development of some main gold leaching systems based on thiosulfate solutions were systematically summarized to illustrate the research status on thiosulfate leaching process.The potential effects of various additives such as organic ligands containing amino,carboxyl or hydroxy functional groups on gold thiosulfate leaching were described in detail.The potential opportunity and challenge for promoting the industrial development of thiosulfate-based gold leaching systems were also discussed.展开更多
The use of mechanical activation to enhance gold recovery from a CuPbZn complex sulfide concentrate was investigated. The effects of milling time, ball size, sample to ball ratio and milling speed on thiosulfate leach...The use of mechanical activation to enhance gold recovery from a CuPbZn complex sulfide concentrate was investigated. The effects of milling time, ball size, sample to ball ratio and milling speed on thiosulfate leaching were studied. Under optimum conditions of milling time 1 h, ball size 20 mm, sample to ball ratio 1/15 and mill speed 600 r/min, nearly 78% of sample is amorphized, particle size decreases from d100=30 μm to d100=8 μm, specific surface area increases from 1.3 m2/g to 4.6 m2/g and gold recovery enhances from 17.4 % in non-activated sample to 73.26 %.展开更多
Leaching from silver sulfide.using a copper-thiosulfate solution in the absence of ammonia was investigated. It is found that silver sulfide could be effectively dissolved in the copper-thiosulfate system without ammo...Leaching from silver sulfide.using a copper-thiosulfate solution in the absence of ammonia was investigated. It is found that silver sulfide could be effectively dissolved in the copper-thiosulfate system without ammonia. The effects of thiosulfate concentration, cop- per-to-thiosulfate ratio, agitation vigorousness, pH values, and dissolved gases on the leaching of silver sulfide with the copper-thiosulfate solution were studied. A maximum extraction of 95.1% was achieved with the 0.12 mol/L thiosulfate and the 0.048 rnol/L copper sulfate. It is shown that copper-to-thiosulfate ratio is an important factor in silver sulfide dissolution and oxygen is not needed to leach silver sulfide, which leads to the instability of the leaching system at high copper-to-thiosulfate ratio. On the other hand, the silver extraction is not affected by the pulp pH values.展开更多
The crevice corrosion behavior of Alloy 690 was investigated in high-temperature chloride solution containing different concentrations of thiosulfate(S_(2)O_(3)^(2-)) and dissolved oxygen(DO). The S2O32- inhibited cor...The crevice corrosion behavior of Alloy 690 was investigated in high-temperature chloride solution containing different concentrations of thiosulfate(S_(2)O_(3)^(2-)) and dissolved oxygen(DO). The S2O32- inhibited corrosion of Alloy 690 through consuming oxygen in aerated chloride solution. In deaerated chloride solution,the S_(2)O_(3)^(2-) was reduced to S° and S^(2-) and subsequently incorporated into the oxide films, which promoted the pitting corrosion at locations of both TiN inclusions and matrix inside the crevice during the crevice corrosion as well as influenced the composition and thickness of the oxide films. The effect mechanisms of S_(2)O_(3)^(2-) and DO on crevice corrosion in high-temperature chloride solution are discussed.展开更多
A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated.Mineralogical studies on the concentrate showed that very fine gold grains(<10μm)were encapsulat...A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated.Mineralogical studies on the concentrate showed that very fine gold grains(<10μm)were encapsulated in pyrite and arsenopyrite,while the proportion of monomer gold was only 21%.The gold-bearing sample was identified as a high-sulfur fine-sized wrapped-type refractory gold concentrate.The gold leaching efficiency obtained by direct cyanidation was only 59.86%.After biooxidation pretreatment,the sulfide minerals were almost completely decomposed,92 wt%of the mineral particles of the biooxidation residue were decreased to<38μm,and the proportion of monomer gold in the biooxidation residue was over 86%.Meanwhile,the gold content in the biooxidation residue was enriched to 55.60 g/t,and the S,Fe,and As contents were reduced to approximately 19.8 wt%,6.97 wt%,and 0.13 wt%,respectively.Ammoniacal thiosulfate was used for gold extraction from the biooxidation residue of the refractory gold concentrate.The results showed that the optimal reagent conditions were 0.18 M thiosulfate,0.02 M copper(II),1.0 M ammonia,and 0.24 M sulfite.Under these conditions,a maximum gold leaching efficiency of 85.05%was obtained.展开更多
A hydrometallurgical process for refractory gold-bearing arsenosulfide concentrates at ambient temperature and pressure was presented, including fine grinding with intensified alkali-leaching （FGIAL）, enhanced agita...A hydrometallurgical process for refractory gold-bearing arsenosulfide concentrates at ambient temperature and pressure was presented, including fine grinding with intensified alkali-leaching （FGIAL）, enhanced agitation alkali-leaching （EAAL）, thiosulfate leaching and displacement. Experimental results on a refractory gold concentrate showed that the total consumption of NaOH in alkaline leaching is only 41% of those theoretically calculated under the conditions of full oxidization for the same amount of arse- nides and sulfides transformed into arsenates and sulfates, and 72.3% of gold is synchro-dissoluted by thiosulfate self-generated during alkaline leaching. After alkaline leaching, thiosulfate leaching was carried out for 24 h. The dissolution of gold is increased to 91.9% from 4.6% by cyanide without the pretreatment. The displacement of gold by zinc powder in the solution gets to 99.2%. Due to an amount of thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal.展开更多
A method for the synthesis of diaryl sulfides from aryl halides in polyethylene glycol was reported.Inodorous Na2S2O3·5H2O,which is readily available as a stable salt,is an effective source of sulfur in the prese...A method for the synthesis of diaryl sulfides from aryl halides in polyethylene glycol was reported.Inodorous Na2S2O3·5H2O,which is readily available as a stable salt,is an effective source of sulfur in the presence of Cu I as catalyst.展开更多
The reaction process for leaching gold from sulfide gold concentrates containing copperwith ammonia-ammonium thiosulfate solution containing copper（Ⅱ）can be divided into initialstage and later stage of reaction.Ini...The reaction process for leaching gold from sulfide gold concentrates containing copperwith ammonia-ammonium thiosulfate solution containing copper（Ⅱ）can be divided into initialstage and later stage of reaction.Initial stage of reaction is controlled by interface reaction.Lat-er stage of reaction is controlled by diffusion process of reaction through solid products layer.Whole leaching process is under the control of corrosion reaction of pyrite bearing gold.Actionof ammonium sulfate in the system is probably as follows:（1）NH<sub>4</sub><sup>+</sup> and NH<sub>3</sub> forms a buffer so-lution;（2）SO<sub>4</sub><sup>2-</sup>ion inhibites the oxidation and decomposition of S<sub>2</sub>O<sub>3</sub><sup>2-</sup>ion.Cu<sup>2+</sup>ion in thesystem acts as an oxidant and oxygen makes the Cu<sup>2-</sup>regenerate.展开更多
The dissolution of silver with thiosulfate and copper ions was studied in a batch-stirred reactor at 25 °C in the absence and presence of various ammonium ions and oxygen concentrations in the aqueous solution. L...The dissolution of silver with thiosulfate and copper ions was studied in a batch-stirred reactor at 25 °C in the absence and presence of various ammonium ions and oxygen concentrations in the aqueous solution. Leaching silver with 4 mg L-1oxygen in the aqueous solution requires high concentration of ammonium and thiosulfate ions. High silver dissolution is achieved at pH of high cupric tetraamine concentration, around pH 9.8, but a high degradation of thiosulfate ions is resulted from their oxidation by the presence of oxygen. When the oxygen concentration is below 1 mg L-1, dissolved silver thiosulfate species are fairly stable and the degradation of thiosulfate ions in the aqueous solution is low. Under these conditions,high silver dissolution is attained using low thiosulfate concentration. At the oxygen concentration of 4 mg L-1,dissolved silver thiosulfate species precipitate out of the aqueous solution significantly affecting silver dissolution.Precipitation of dissolved silver thiosulfate species occurs because of oxidation of the thiosulfate bonding to the silver.展开更多
Hypothesis： To determine the pharmacokinetics of sodium thiosulfate in the inner ear perilymph following middle ear application in Guinea pigs. Background： Cisplatin chemotherapy is often associated with a dose-depe...Hypothesis： To determine the pharmacokinetics of sodium thiosulfate in the inner ear perilymph following middle ear application in Guinea pigs. Background： Cisplatin chemotherapy is often associated with a dose-dependent high frequency senso- rineural hearing loss. Sodium thiosulfate has been shown to reduce cisplatin-induced ototoxicity when given intravenously, but this may limit the tumoricidal effects of the chemotherapy. Recent animal studies looking at middle ear application of sodium thiosulfate have shown prevention of outer hair cell and hearing loss, but the perilymph pharmacokinetics have not yet been established. Methods： Twenty Guinea pig ears were split into two groups and administered sodium thiosulfate to the middle ear at either a concentration of 250 mg/mL or 50 mg/mL for 30 min. Perilymph samples were then obtained serially through the round window over 6 h. Sodium thiosulfate concentrations were obtained using high-pressure liquid chromatography. Results： The 250 mg/mL group had a maximum perilymph concentration of 7.27 mg/mL （±0.83） that decreased to 0.94 mg/mL （±0.03） over 6 h. The 50 mg/mL group had an initial concentration of 1.63 mg/mL （±0.17） and was undetectable after 1 h. The half-life of sodium thiosulfate within perilymph was 0.74 h. Conclusions： and Relevance： The results of this study show that sodium thiosulfate is capable of diffusing through round window and into the inner ear perilymph. Peak levels decline over several hours after exposure. This has a potential application as a localized therapy in the prevention of cisplatin induced ototoxicity.展开更多
Electrocatalytic oxidation of thiosulfate at the 2,7-BFEFMCPE occurs at a potential about 460 mV less positive than that unmodified carbon paste electrode.The diffusion coefficient（=5.6×10^-5）cm^2 s^-1）,the ki...Electrocatalytic oxidation of thiosulfate at the 2,7-BFEFMCPE occurs at a potential about 460 mV less positive than that unmodified carbon paste electrode.The diffusion coefficient（=5.6×10^-5）cm^2 s^-1）,the kinetic parameters such as electron transfer coefficient,（=0.5） and kh（=1.21×10^-3 cm s^-1） of thiosulfate oxidation at the surface of,2,7-BFEFMCPE were determined.The electrocatalytic oxidation peak current of thiosulfate showed two linear dynamic ranges（0.0006-0.009 mmol/L and 0.009- 0.900 mmol/L） and a detection limit of 0.00015 mmol/L.This method was also examined as a new electrochemical sensor for the determination of thiosulfate in real sample.展开更多
Sodium alkyl thiosulfates(Bunte salts) can be readily reduced to the corresponding disulfides with TiCl4/Sm system in good to excellent yields under mild conditions
Objective:To compare the anti-proliferative effect of sodium thiosulfate on human colorectal cancer cells(HT-29)and normal small intestine cells(IEC6).Methods:Cells(HT-29 and IEC6)were treated with different concentra...Objective:To compare the anti-proliferative effect of sodium thiosulfate on human colorectal cancer cells(HT-29)and normal small intestine cells(IEC6).Methods:Cells(HT-29 and IEC6)were treated with different concentrations of sodium thiosulfate ranging from 0.5 m M to 80 m M for 24 h.Cell viability was measured via crystal violet and MTT assays.HT-29 cells were further treated in the presence and absence of mitochondrial electron transport chain(ETC)inhibitors,KATP channel opener and closer and H2S inhibitors for 24 h followed by sodium thiosulfate in order to study their respective roles in the anti-proliferative activity of sodium thiosulfate.Results:The IC50 values of sodium thiosulfate on HT-29 cells were 40.93 m M and 42.45 m M by crystal violet and MTT assay whereas,in the case of IEC6 cells,the values were 45.17 m M and 47.22 m M.The inhibition of endogenous H2S enzymes and KATP channel induced no change in the anti-proliferative capacity of sodium thiosulfate.However,the anti-proliferative activity of sodium thiosulfate was enhanced in the presence of mitochondrial ETC inhibitors.Conclusions:HT-29 cell growth is effectively attenuated by sodium thiosulfate and the anti-proliferative activity of sodium thiosulfate is enhanced in the presence of mitochondrial ETC inhibitors.展开更多
基金financial support of the Yunnan Major Scientific and Technological Project,China(No.202302AG050008)Yunnan Fundamental Research Project,China(No.202101BE070001-023)“Yunnan Revitalization Talents Support Plan”High-End Foreign Talents Program,China。
文摘The oxidation characteristics of sulfite and thiosulfate were examined by using thermodynamic calculations and simulated desulfurization solution experiments to investigate their difference.Subsequently,a new multistage oxidation method using oxygen−ammonium persulfate was presented and applied to the oxidation of a real desulfurization solution.The results show that the concentrations of thiosulfate and sulfite in the real desulfurization solution decrease from 48.76 and 61.76 g/L to 2.24 and 0.02 g/L,respectively,and the ammonium sulfate products obtained are white with uniform particles.In addition,compared with ammonium persulfate alone,the multistage oxidation method can reduce the ammonium persulfate addition by 37.56%and treatment cost by 28.13%.
基金financially supported by the National Natural Science Foundation of China(No.52104349)Henan Provincial Science and Technology R&D Plan Joint Fund Project(No.232103810032)+1 种基金the Funds for HAUST Young Cadre Teacher(No.400213450022)supporting by China Postdoctoral Science Foundation(No.2022M721031)。
文摘This study addresses the global problem of the detoxification of cadmium(Cd)-containing solid waste by developing an eco-friendly thiosulfate system for extracting the negative electrode materials from spent Ni–Cd batteries and proposing an ultraviolet(UV)photolysis technology for the green recycling of the Cd in the resultant leached solution.Cd extraction is performed using both simple thiosulfate and cuprous thiosulfate systems,with the cuprous thiosulfate system exhibiting a superior leaching performance(80%),as compared with that of the simple thiosulfate system(36%).X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)analyses reveal the formation of copper sulfide on the surface of the Ni–Cd batteries leaching residue,which is confirmed by Cdleaching kinetics fitting using the shrinking-core model.Following UV exposure,95%of the Cd precipitates from the leaching solution to form CdS.Transmission electron microscopy(TEM)characterization and particle size distribution reveal that the CdS contains 100–150 nm-diameter spherical particles with compact surface structures.Electrochemical performance tests and UV–visible diffuse reflectance spectra(UV–Vis DRS)analyses demonstrate that the UV-photolysis product exhibits excellent photoelectric conversion characteristics.Photocatalytic activity tests of the recovered CdS confirm that the photocatalytic degradation ratio of methyl orange is 87%,indicating the successful green recycling of Cd from spent Ni–Cd batteries,which improves its potential application in the field of photocatalysis.
基金the financial support from the Natural Science Foundation of Hunan Province, China (No. 2023JJ40723)China Postdoctoral Science Foundation (No. 2022M723549)the National Natural Science Foundation of China (Nos. 52174271, 51504293)。
文摘The adsorption behaviors and mechanisms of gold from thiosulfate solution on strong-base anion exchange resin were systematically investigated.The comparison experiment of adsorption ability and selectivity for gold showed that gel Amberlite IRA-400 resin with Type Ⅰ quaternary ammonium functional group had better adsorption performance.The increases of resin dosage,ammonia concentration and solution pH were favorable to gold adsorption,whereas the rises of cupric and thiosulfate concentrations were disadvantageous to gold loading.Microscopic characterization results indicated that gold was adsorbed in the form of [Au(S_(2)O_(3))_(2)]^(3–) complex anion by exchanging with the counter ion Cl^(–) in the functional group of the resin.Density functional theory calculation result manifested that gold adsorption was mainly depended on the hydrogen bond and van der Waals force generated between O atom in [Au(S_(2)O_(3))_(2)]^(3–) and H atom in the quaternary ammonium functional group of the resin.
基金The National Natural Science Foundation of China under contract Nos 91951201 and 42030412the National Key R&D Program of China under contract No.2021YFF0501304the Scientific Research Foundation of Third Institute of Oceanography,MNR under contract No.2019021.
文摘The genus Marinobacter is very broadly distributed in global environments and is considered as aerobic heterotroph.In this study,six Marinobacter strains were identified with autotrophic thiosulfate oxidation capacity.These strains,namely Marinobacter guineae M3B^(T),Marinobacter aromaticivorans D15-8PT,Marinobacter vulgaris F01^(T),Marinobacter profundi PWS21^(T),Marinobacter denitrificans JB02H27T,and Marinobacter sp.ST-1M(with a 99.93%similarity to the 16S rDNA sequences of Marinobacter salsuginis SD-14B^(T)),were screened out of 32 Marinobacter strains by autotrophic thiosulfate oxidization medium.The population of cells grew in a chemolithotrophic medium,increasing from 105 cells/mL to 10^(7) cells/mL within 5 d.This growth was accompanied by the consumption of thiosulfate 3.59 mmol/L to 9.64 mmol/L and the accumulation of sulfate up to 0.96 mmol/L,and occasionally produced sulfur containing complex particles.Among these Marinobacter strains,it was also found their capability of oxidizing thiosulfate to sulfate in a heterotrophic medium.Notably,M.vulgaris F01^(T)and M.antarcticus ZS2-30^(T)showed highly significant production of sulfate at 9.45 mmol/L and 3.10 mmol/L.Genome annotation indicated that these Marinobacter strains possess a complete Sox cluster for thiosulfate oxidation.Further phylogenetic analysis of the soxB gene revealed that six Marinobacter strains formed a separate lineage within Gammaproteobacteria and close to obligate chemolithoautotroph Thiomicrorhabdus arctica.The results indicated that thiosulfate oxidizing and chemolithoautotrophic potential in Marinobacter genus,which may contribute to the widespread of Marinobacter in the global ocean.
文摘Carbon supported Pt-based intermetallic compounds(IMCs)with high activity and durability are the most competitive cathode catalysts for the commercialization of proton exchange membrane fuel cells(PEMFCs).The synthesis of Pt-based intermetallics with a good balance between small size and high metal loading remains challenging because of the high-temperature annealing that is generally required to form intermetallic phases.We developed a sodium thiosulfate-assisted impregnation strategy to synthesize small-sized and highly ordered PtM IMCs catalysts(M=Co,Fe,Ni)with high-Pt-content(up to 44.5 wt%).During the impregnation process,thiosulfate could reduce H_(2)PtCl6 to form uniformly dispersed Pt colloid on carbon supports,which in turn prevents the aggregation of Pt at the low-temperature annealing stage.Additionally,the strong interaction between Pt and S inhibits particle sintering,ensuring the formation of small-sized and uniform PtM intermetallic catalysts at the high-temperature annealing stage.The optimized intermetallic PtCo catalyst delivered a high mass activity of 0.72 A mgPt^(–1)and a large power performance of 1.17 W·cm^(–2)at 0.65 V under H_(2)-air conditions,along with 74%mass activity retention after the accelerated stress test.
基金Project (50771042) supported by the National Natural Science Foundation of ChinaProjects (1041005100052009HASTIT023) supported by the Program for Science and Technology Innovation Talents of Henan Province,China
文摘Cyanide-free silver electroplating was conducted in thiosulfate baths containing AgNO3 and AgBr major salts, respectively. The effects of major salt content and current density on surface quality, deposition rate and microhardness of Ag coatings were investigated. The optimized electroplating parameters were established. The adhesion strength of Ag coating on Cu substrate was evaluated and the grain size of Ag coating was measured under optimized electroplating parameters. The optimized AgNO3 content is 40 g/L with current density of 0.25 A/dm2. The deposited bright, smooth, and well adhered Ag coating had nanocrystalline grains with mean size of 35 nm. The optimized AgBr content was 30 g/L with current density of 0.20 A/dm2. The resultant Ag coating had nanocrystalline grains with mean size of 55 nm. Compared with the bath containing AgBr main salt, the bath containing AgNO3 main salt had a wider current density range, and corresponding Ag coating had a higher microhardness and a smaller grain size.
基金Project(51074182)supported by the National Natural Science Foundation of ChinaProject(2014M550422)supported by the Postdoctoral Science Foundation,ChinaProject(2015JJ3149)supported by the Natural Science Foundation of Hunan Province,China
文摘Arsenopyrite was artificially added into the thiosulfate leaching solution to clarify the role of arsenopyrite on the thiosulfate leaching of gold.The effect of arsenopyrite on the thiosulfate leaching of gold was studied by the thermodynamic calculation,mineral dissolution test,leaching test and XPS analysis.The results show that the thiosulfate consumption slightly increases with increasing the concentration of arsenopyrite,but the gold dissolution is obviously hindered.This may mainly attribute to the catalytic effect of arsenopyrite on the thiosulfate decomposition and the formation of passivation layer on the gold foil surface.The passivation layer likely consists of Cu2S or Cu（S2O3）35-,element S,FeOOH and iron arsenate,which is deduced from the XPS analysis.However,the negative effect of arsenopyrite can be eliminated by adding additives.It is found that both additives of sodium carboxymethyl（CMC） and sodium phosphate（SHPP） can not only decrease the thiosulfate consumption but also improve the gold dissolution.
基金financial supports from the Fundamental Research Funds for Central Universities of China (No. N182502044)。
文摘Numerous non-cyanide leaching lixiviants have been developed,among which thiosulfate is considered the most promising alternative to cyanide due to its non-toxicity,low price,high leaching rate and excellent characteristics in dealing with carbonaceous and copper-bearing gold ores.The traditional copper−ammonia−thiosulfate system has been studied extensively.However,with many years of process development,there are still some problems and challenges with this gold leaching system.A series of studies using nickel-,cobalt-and ferric-based catalyst to substitute copper have been conducted with the purpose of reducing the consumption of thiosulfate.A variety of non-ammonia thiosulfate leaching systems including oxygen−thiosulfate,copper−thiosulfate,copper−EDA−thiosulfate,ferric−EDTA−thiosulfate,and ferric−oxalate−thiosulfate leaching systems have been also developed to eliminate the potential side-effect of ammonia.In this review,the basic theory and process development of some main gold leaching systems based on thiosulfate solutions were systematically summarized to illustrate the research status on thiosulfate leaching process.The potential effects of various additives such as organic ligands containing amino,carboxyl or hydroxy functional groups on gold thiosulfate leaching were described in detail.The potential opportunity and challenge for promoting the industrial development of thiosulfate-based gold leaching systems were also discussed.
基金supported by Iran Mineral Processing Research Center (IMPRC)the IMPRC for the financial support of this work
文摘The use of mechanical activation to enhance gold recovery from a CuPbZn complex sulfide concentrate was investigated. The effects of milling time, ball size, sample to ball ratio and milling speed on thiosulfate leaching were studied. Under optimum conditions of milling time 1 h, ball size 20 mm, sample to ball ratio 1/15 and mill speed 600 r/min, nearly 78% of sample is amorphized, particle size decreases from d100=30 μm to d100=8 μm, specific surface area increases from 1.3 m2/g to 4.6 m2/g and gold recovery enhances from 17.4 % in non-activated sample to 73.26 %.
基金supported by the Joint Foundation of the National Natural Science Foundation Committee and Yunnan Provincial Government of China (No. U0937602)
文摘Leaching from silver sulfide.using a copper-thiosulfate solution in the absence of ammonia was investigated. It is found that silver sulfide could be effectively dissolved in the copper-thiosulfate system without ammonia. The effects of thiosulfate concentration, cop- per-to-thiosulfate ratio, agitation vigorousness, pH values, and dissolved gases on the leaching of silver sulfide with the copper-thiosulfate solution were studied. A maximum extraction of 95.1% was achieved with the 0.12 mol/L thiosulfate and the 0.048 rnol/L copper sulfate. It is shown that copper-to-thiosulfate ratio is an important factor in silver sulfide dissolution and oxygen is not needed to leach silver sulfide, which leads to the instability of the leaching system at high copper-to-thiosulfate ratio. On the other hand, the silver extraction is not affected by the pulp pH values.
基金financially supported by the National Natural Science Foundation of China (Nos. 51671201, 51971230)the National Science and Technology Major Project (No. 2017ZX06002003004-002)the Key Programs of the Chinese Academy of Sciences (Research on the Development of Nuclear Power Materials and Service Security Technology), (No. ZDRW-CN-2017-1)。
文摘The crevice corrosion behavior of Alloy 690 was investigated in high-temperature chloride solution containing different concentrations of thiosulfate(S_(2)O_(3)^(2-)) and dissolved oxygen(DO). The S2O32- inhibited corrosion of Alloy 690 through consuming oxygen in aerated chloride solution. In deaerated chloride solution,the S_(2)O_(3)^(2-) was reduced to S° and S^(2-) and subsequently incorporated into the oxide films, which promoted the pitting corrosion at locations of both TiN inclusions and matrix inside the crevice during the crevice corrosion as well as influenced the composition and thickness of the oxide films. The effect mechanisms of S_(2)O_(3)^(2-) and DO on crevice corrosion in high-temperature chloride solution are discussed.
基金financially supported by the Special Funds for the National Natural Science Foundation of China(No.U1608254)the Open Fund of State Key Laboratory of Comprehensive Utilization of Low-Grade Refractory Gold Ores(No.ZJKY2017(B)KFJJ01 and ZJKY2017(B)KFJJ02)。
文摘A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated.Mineralogical studies on the concentrate showed that very fine gold grains(<10μm)were encapsulated in pyrite and arsenopyrite,while the proportion of monomer gold was only 21%.The gold-bearing sample was identified as a high-sulfur fine-sized wrapped-type refractory gold concentrate.The gold leaching efficiency obtained by direct cyanidation was only 59.86%.After biooxidation pretreatment,the sulfide minerals were almost completely decomposed,92 wt%of the mineral particles of the biooxidation residue were decreased to<38μm,and the proportion of monomer gold in the biooxidation residue was over 86%.Meanwhile,the gold content in the biooxidation residue was enriched to 55.60 g/t,and the S,Fe,and As contents were reduced to approximately 19.8 wt%,6.97 wt%,and 0.13 wt%,respectively.Ammoniacal thiosulfate was used for gold extraction from the biooxidation residue of the refractory gold concentrate.The results showed that the optimal reagent conditions were 0.18 M thiosulfate,0.02 M copper(II),1.0 M ammonia,and 0.24 M sulfite.Under these conditions,a maximum gold leaching efficiency of 85.05%was obtained.
基金This project was financially supported by the Natural Science Foundation of Liaoning Province of China (No.2001101015) and theFree Study Item of the Institute of Metal Research, Chinese Academy of Sciences (No.AM05-0866)
文摘A hydrometallurgical process for refractory gold-bearing arsenosulfide concentrates at ambient temperature and pressure was presented, including fine grinding with intensified alkali-leaching （FGIAL）, enhanced agitation alkali-leaching （EAAL）, thiosulfate leaching and displacement. Experimental results on a refractory gold concentrate showed that the total consumption of NaOH in alkaline leaching is only 41% of those theoretically calculated under the conditions of full oxidization for the same amount of arse- nides and sulfides transformed into arsenates and sulfates, and 72.3% of gold is synchro-dissoluted by thiosulfate self-generated during alkaline leaching. After alkaline leaching, thiosulfate leaching was carried out for 24 h. The dissolution of gold is increased to 91.9% from 4.6% by cyanide without the pretreatment. The displacement of gold by zinc powder in the solution gets to 99.2%. Due to an amount of thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal.
基金the Persian Gulf University Research Council for generous partial financial support of this study
文摘A method for the synthesis of diaryl sulfides from aryl halides in polyethylene glycol was reported.Inodorous Na2S2O3·5H2O,which is readily available as a stable salt,is an effective source of sulfur in the presence of Cu I as catalyst.
基金Supported by the National Nature Science Foundation of China
文摘The reaction process for leaching gold from sulfide gold concentrates containing copperwith ammonia-ammonium thiosulfate solution containing copper（Ⅱ）can be divided into initialstage and later stage of reaction.Initial stage of reaction is controlled by interface reaction.Lat-er stage of reaction is controlled by diffusion process of reaction through solid products layer.Whole leaching process is under the control of corrosion reaction of pyrite bearing gold.Actionof ammonium sulfate in the system is probably as follows:（1）NH<sub>4</sub><sup>+</sup> and NH<sub>3</sub> forms a buffer so-lution;（2）SO<sub>4</sub><sup>2-</sup>ion inhibites the oxidation and decomposition of S<sub>2</sub>O<sub>3</sub><sup>2-</sup>ion.Cu<sup>2+</sup>ion in thesystem acts as an oxidant and oxygen makes the Cu<sup>2-</sup>regenerate.
基金Research and Technology Development Center, Administrative Services of Pennoles for the financial support of this Research Project
文摘The dissolution of silver with thiosulfate and copper ions was studied in a batch-stirred reactor at 25 °C in the absence and presence of various ammonium ions and oxygen concentrations in the aqueous solution. Leaching silver with 4 mg L-1oxygen in the aqueous solution requires high concentration of ammonium and thiosulfate ions. High silver dissolution is achieved at pH of high cupric tetraamine concentration, around pH 9.8, but a high degradation of thiosulfate ions is resulted from their oxidation by the presence of oxygen. When the oxygen concentration is below 1 mg L-1, dissolved silver thiosulfate species are fairly stable and the degradation of thiosulfate ions in the aqueous solution is low. Under these conditions,high silver dissolution is attained using low thiosulfate concentration. At the oxygen concentration of 4 mg L-1,dissolved silver thiosulfate species precipitate out of the aqueous solution significantly affecting silver dissolution.Precipitation of dissolved silver thiosulfate species occurs because of oxidation of the thiosulfate bonding to the silver.
文摘Hypothesis： To determine the pharmacokinetics of sodium thiosulfate in the inner ear perilymph following middle ear application in Guinea pigs. Background： Cisplatin chemotherapy is often associated with a dose-dependent high frequency senso- rineural hearing loss. Sodium thiosulfate has been shown to reduce cisplatin-induced ototoxicity when given intravenously, but this may limit the tumoricidal effects of the chemotherapy. Recent animal studies looking at middle ear application of sodium thiosulfate have shown prevention of outer hair cell and hearing loss, but the perilymph pharmacokinetics have not yet been established. Methods： Twenty Guinea pig ears were split into two groups and administered sodium thiosulfate to the middle ear at either a concentration of 250 mg/mL or 50 mg/mL for 30 min. Perilymph samples were then obtained serially through the round window over 6 h. Sodium thiosulfate concentrations were obtained using high-pressure liquid chromatography. Results： The 250 mg/mL group had a maximum perilymph concentration of 7.27 mg/mL （±0.83） that decreased to 0.94 mg/mL （±0.03） over 6 h. The 50 mg/mL group had an initial concentration of 1.63 mg/mL （±0.17） and was undetectable after 1 h. The half-life of sodium thiosulfate within perilymph was 0.74 h. Conclusions： and Relevance： The results of this study show that sodium thiosulfate is capable of diffusing through round window and into the inner ear perilymph. Peak levels decline over several hours after exposure. This has a potential application as a localized therapy in the prevention of cisplatin induced ototoxicity.
文摘Electrocatalytic oxidation of thiosulfate at the 2,7-BFEFMCPE occurs at a potential about 460 mV less positive than that unmodified carbon paste electrode.The diffusion coefficient（=5.6×10^-5）cm^2 s^-1）,the kinetic parameters such as electron transfer coefficient,（=0.5） and kh（=1.21×10^-3 cm s^-1） of thiosulfate oxidation at the surface of,2,7-BFEFMCPE were determined.The electrocatalytic oxidation peak current of thiosulfate showed two linear dynamic ranges（0.0006-0.009 mmol/L and 0.009- 0.900 mmol/L） and a detection limit of 0.00015 mmol/L.This method was also examined as a new electrochemical sensor for the determination of thiosulfate in real sample.
文摘Sodium alkyl thiosulfates(Bunte salts) can be readily reduced to the corresponding disulfides with TiCl4/Sm system in good to excellent yields under mild conditions
文摘Objective:To compare the anti-proliferative effect of sodium thiosulfate on human colorectal cancer cells(HT-29)and normal small intestine cells(IEC6).Methods:Cells(HT-29 and IEC6)were treated with different concentrations of sodium thiosulfate ranging from 0.5 m M to 80 m M for 24 h.Cell viability was measured via crystal violet and MTT assays.HT-29 cells were further treated in the presence and absence of mitochondrial electron transport chain(ETC)inhibitors,KATP channel opener and closer and H2S inhibitors for 24 h followed by sodium thiosulfate in order to study their respective roles in the anti-proliferative activity of sodium thiosulfate.Results:The IC50 values of sodium thiosulfate on HT-29 cells were 40.93 m M and 42.45 m M by crystal violet and MTT assay whereas,in the case of IEC6 cells,the values were 45.17 m M and 47.22 m M.The inhibition of endogenous H2S enzymes and KATP channel induced no change in the anti-proliferative capacity of sodium thiosulfate.However,the anti-proliferative activity of sodium thiosulfate was enhanced in the presence of mitochondrial ETC inhibitors.Conclusions:HT-29 cell growth is effectively attenuated by sodium thiosulfate and the anti-proliferative activity of sodium thiosulfate is enhanced in the presence of mitochondrial ETC inhibitors.
