Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of ...Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.展开更多
Fe（Ⅱ） was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%---4% HF to remove ...Fe（Ⅱ） was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%---4% HF to remove the SiO2 template and then calcined. It was found that nanowire bundles, dendritic plates of porous iron oxide, dense parallel backbones of porous iron oxide were obtained at -1.4-- -1.6 V and 0.08--0.1 mol/L electrolyte concentration after calcinations; the dendritic pattern of porous iron oxide film templated by the SBA-16 film was obtained in macrostructure at a higher absolute value of cathode potential（-1.7-- -1.8 V） and a lower electrolyte concentration（0.02-0.05 mol/L）, the dendritic pattern of porous iron oxide film could copy the microstructure of SBA-16 film; Fe（II） nanowires grew and formed in one dimension（1D） and two-dimension（2D） electrocrystallization at a potential of-l.6-- -1.7 V and an electrolyte concentration of 0.05 mol/L, and the shape of the ID or 2D crystalline iron oxide nanowires calcined was similar to the original shape of the SBA-16 channels. The desired morphology and size of porous nanocrystal iron oxide can be obtained by adjusting the applied potential value and electrolyte concentration, and all kinds of morphologies of porous nanostructure crystal iron oxide can be prepared.展开更多
A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained ...A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.展开更多
Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimat...Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimate the transportations of these minerals. Fourteen soil samples and fifteen plant samples were collected from sites located in the basin and also in neighboring area and chemically analyzed.In展开更多
The Hadamengou gold deposit is located in western part of the northern margin of the North China craton. It is a hydrothermal deposit related to alkaline magmatism. Dissolution of Au, Fe from pyrite and iron oxide （i...The Hadamengou gold deposit is located in western part of the northern margin of the North China craton. It is a hydrothermal deposit related to alkaline magmatism. Dissolution of Au, Fe from pyrite and iron oxide （including magnetite and hematite） individual minerals in the three main types of ore shows： in iron oxides （magnetite and hematite）, Au and Fe were dissolved simultaneously and their solubilities are positively correlated, which means Au is mainly chemical-bonded （lattice gold） and/or colloidal-adsorbed in iron oxides; while in pyrite, on the contrary, Au dissolution obviously lags behind Fe and the solubility of Au shows negative relationship with that of Fe, which indicates Au is mainly hosted as grains of elemental gold （or native gold） within pyrite. Previous studies revealed that the Hadamengou gold deposit is characterized by intensive K-feldspathization and holds high content of iron oxides occasionally replaced by sulfides, which was caused by oxidizing K-enriched alkaline fluids under a stretching geodynamic setting. These geological features, together with the high Au-content in iron oxides, comparable with that of the Olympic Dam deposit in South Australia, suggest that this deposit is the first example of iron oxide-type gold deposits in China.展开更多
It is quite evident that it is not anomalous metal transport,nor unique depositional conditions,nor any single factor at the deposit scale,that dictates whether a mineral deposit becomes a giant or not.A hierarchical ...It is quite evident that it is not anomalous metal transport,nor unique depositional conditions,nor any single factor at the deposit scale,that dictates whether a mineral deposit becomes a giant or not.A hierarchical approach thus is required to progressively examine controlling parameters at successively decreasing scales in the total mineral system to understand the location of giant gold deposits in non-arc environments.For giant orogenic,intrusion-related gold systems（IRGS） and Carlin-type gold deposits and iron oxide-copper-gold（IOCG） deposits,there are common factors among all of these at the lithospheric to crustal scale.All are sited in giant gold provinces controlled by complex fundamental fault or shear zones that follow craton margins or,in the case of most Phanerozoic orogenic giants,define the primary suture zones between tectonic terranes.Giant provinces of IRGS,IOCG,and Carlin-type deposits require melting of metasomatized lithosphere beneath craton margins with ascent of hybrid lamprophyric to granitic magmas and associated heat flux to generate the giant province.The IRGS and IOCG deposits require direct exsolution of volatile-rich magmatic-hydrothermal fluids,whereas the association of such melts with Carlin-type ores is more indirect and enigmatic.Giant orogenic gold provinces show no direct relationship to such magmatism.forming from metamorphic fluids,but show an indirect relationship to lamprophyres that reflect the mantle connectivity of controlling first-order structures.In contrast to their province scale similarities,the different giant gold deposit styles show contrasting critical controls at the district to deposit scale.For orogenic gold deposits,the giants appear to have formed by conjunction of a greater number of parameters to those that control smaller deposits,with resultant geometrical and lithostratigraphic complexity as a guide to their location.There are few giant IRGS due to their inferior fluid-flux systems relative to orogenic gold deposits,and those few giants are essentially preservational exceptions.Many Carlin-type deposits are giants due to the exceptional conjunction of both structural and lithological parameters that caused reactive and permeable rocks,enriched in syngenetic gold,to be located below an impermeable cap along antiformal ＂trends＂.Hydrocarbons probably played an important role in concentrating metal.The supergiant Post-Betze deposit has additional ore zones in strain heterogeneities surrounding the pre-gold Goldstrike stock.All unequivocal IOCG deposits are giant or near-giant deposits in terms of gold-equivalent resources,partly due to economic factors for this relatively poorly understood,low Cu-Au grade deposit type.The supergiant Olympic Dam deposit,the most shallowly formed deposit among the larger IOCGs,probably owes its origin to eruption of volatile-rich hybrid magma at surface,with formation of a large maar and intense and widespread brecciation,alteration and Cu-Au-U deposition in a huge rock volume.展开更多
Corrosion scales play an important role in modifying water quality in drinking water distribution systems. The corrosion scales from old water pipe lines were analyzed for their structure and composition. This paper p...Corrosion scales play an important role in modifying water quality in drinking water distribution systems. The corrosion scales from old water pipe lines were analyzed for their structure and composition. This paper presents the results of comprehensive study of deposits found in water distribution system of Ulhasnagar city of Maharashtra, India. Scales were investigated by XRD, FTIR, SEM and ED’s analytical techniques. It was found that goethite, magnetite, lepidocrocite, hematite and Akaganite were identified as the primary constituents of brown deposits. The corrosion scales had a shell-like, enveloping layer, covering porous deposits of iron oxide phases. Our studies were able to identify important constituents of three different pipes of water distribution systems. Akaganite was found to be present in chloride environment. Along with iron hydroxide phases it was found that corrosion product also contain some organic matter which may be due to adsorption of biofilm on the surface of pipe. Further studies are needed to establish the role of corrosion scales in the mechanism of iron release from corroded pipes.展开更多
The Lala Cu deposit in Sichuan Province is one of the most important large deposits in SW China,both in terms of Cu and associated Au-Mo-Co-REE-Fe. Systematic ore petrology study shows that ore minerals are mainly com...The Lala Cu deposit in Sichuan Province is one of the most important large deposits in SW China,both in terms of Cu and associated Au-Mo-Co-REE-Fe. Systematic ore petrology study shows that ore minerals are mainly composed of hydrothermal magnetite,chalcopyrite and molybdenite.The wall-rock alterations include biotitization,silicification, carbonatation,albitization,potash feldspathization, apatitation,actinolitation and fluoritation,et al. The Pyrite and magnetite have euhedral-subhedral crystalline grained texture and the chalcopyrite展开更多
基金supported by Thailand Science Research and Innovation Fund Chulalongkorn University,Thailand(IND66210014)。
文摘Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.
基金Supported by the National Natural Science Foundation of China(No.20676027)Postdoctoral Foundation of Heilongjiang Province,China(No.LBH-Q07111)
文摘Fe（Ⅱ） was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%---4% HF to remove the SiO2 template and then calcined. It was found that nanowire bundles, dendritic plates of porous iron oxide, dense parallel backbones of porous iron oxide were obtained at -1.4-- -1.6 V and 0.08--0.1 mol/L electrolyte concentration after calcinations; the dendritic pattern of porous iron oxide film templated by the SBA-16 film was obtained in macrostructure at a higher absolute value of cathode potential（-1.7-- -1.8 V） and a lower electrolyte concentration（0.02-0.05 mol/L）, the dendritic pattern of porous iron oxide film could copy the microstructure of SBA-16 film; Fe（II） nanowires grew and formed in one dimension（1D） and two-dimension（2D） electrocrystallization at a potential of-l.6-- -1.7 V and an electrolyte concentration of 0.05 mol/L, and the shape of the ID or 2D crystalline iron oxide nanowires calcined was similar to the original shape of the SBA-16 channels. The desired morphology and size of porous nanocrystal iron oxide can be obtained by adjusting the applied potential value and electrolyte concentration, and all kinds of morphologies of porous nanostructure crystal iron oxide can be prepared.
文摘A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.
文摘Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimate the transportations of these minerals. Fourteen soil samples and fifteen plant samples were collected from sites located in the basin and also in neighboring area and chemically analyzed.In
基金This research was supported by Gold specialties Science Foundation of Finance Ministry （Grant Nos. 22800802039）；Yang Liqin, Niu Cuiyi and Zhao Yinyin are thanked for theirs participation in part of the work for this paper.
文摘The Hadamengou gold deposit is located in western part of the northern margin of the North China craton. It is a hydrothermal deposit related to alkaline magmatism. Dissolution of Au, Fe from pyrite and iron oxide （including magnetite and hematite） individual minerals in the three main types of ore shows： in iron oxides （magnetite and hematite）, Au and Fe were dissolved simultaneously and their solubilities are positively correlated, which means Au is mainly chemical-bonded （lattice gold） and/or colloidal-adsorbed in iron oxides; while in pyrite, on the contrary, Au dissolution obviously lags behind Fe and the solubility of Au shows negative relationship with that of Fe, which indicates Au is mainly hosted as grains of elemental gold （or native gold） within pyrite. Previous studies revealed that the Hadamengou gold deposit is characterized by intensive K-feldspathization and holds high content of iron oxides occasionally replaced by sulfides, which was caused by oxidizing K-enriched alkaline fluids under a stretching geodynamic setting. These geological features, together with the high Au-content in iron oxides, comparable with that of the Olympic Dam deposit in South Australia, suggest that this deposit is the first example of iron oxide-type gold deposits in China.
基金funded by Talent Award under the 1000 Plan Project from the Chinese Government
文摘It is quite evident that it is not anomalous metal transport,nor unique depositional conditions,nor any single factor at the deposit scale,that dictates whether a mineral deposit becomes a giant or not.A hierarchical approach thus is required to progressively examine controlling parameters at successively decreasing scales in the total mineral system to understand the location of giant gold deposits in non-arc environments.For giant orogenic,intrusion-related gold systems（IRGS） and Carlin-type gold deposits and iron oxide-copper-gold（IOCG） deposits,there are common factors among all of these at the lithospheric to crustal scale.All are sited in giant gold provinces controlled by complex fundamental fault or shear zones that follow craton margins or,in the case of most Phanerozoic orogenic giants,define the primary suture zones between tectonic terranes.Giant provinces of IRGS,IOCG,and Carlin-type deposits require melting of metasomatized lithosphere beneath craton margins with ascent of hybrid lamprophyric to granitic magmas and associated heat flux to generate the giant province.The IRGS and IOCG deposits require direct exsolution of volatile-rich magmatic-hydrothermal fluids,whereas the association of such melts with Carlin-type ores is more indirect and enigmatic.Giant orogenic gold provinces show no direct relationship to such magmatism.forming from metamorphic fluids,but show an indirect relationship to lamprophyres that reflect the mantle connectivity of controlling first-order structures.In contrast to their province scale similarities,the different giant gold deposit styles show contrasting critical controls at the district to deposit scale.For orogenic gold deposits,the giants appear to have formed by conjunction of a greater number of parameters to those that control smaller deposits,with resultant geometrical and lithostratigraphic complexity as a guide to their location.There are few giant IRGS due to their inferior fluid-flux systems relative to orogenic gold deposits,and those few giants are essentially preservational exceptions.Many Carlin-type deposits are giants due to the exceptional conjunction of both structural and lithological parameters that caused reactive and permeable rocks,enriched in syngenetic gold,to be located below an impermeable cap along antiformal ＂trends＂.Hydrocarbons probably played an important role in concentrating metal.The supergiant Post-Betze deposit has additional ore zones in strain heterogeneities surrounding the pre-gold Goldstrike stock.All unequivocal IOCG deposits are giant or near-giant deposits in terms of gold-equivalent resources,partly due to economic factors for this relatively poorly understood,low Cu-Au grade deposit type.The supergiant Olympic Dam deposit,the most shallowly formed deposit among the larger IOCGs,probably owes its origin to eruption of volatile-rich hybrid magma at surface,with formation of a large maar and intense and widespread brecciation,alteration and Cu-Au-U deposition in a huge rock volume.
文摘Corrosion scales play an important role in modifying water quality in drinking water distribution systems. The corrosion scales from old water pipe lines were analyzed for their structure and composition. This paper presents the results of comprehensive study of deposits found in water distribution system of Ulhasnagar city of Maharashtra, India. Scales were investigated by XRD, FTIR, SEM and ED’s analytical techniques. It was found that goethite, magnetite, lepidocrocite, hematite and Akaganite were identified as the primary constituents of brown deposits. The corrosion scales had a shell-like, enveloping layer, covering porous deposits of iron oxide phases. Our studies were able to identify important constituents of three different pipes of water distribution systems. Akaganite was found to be present in chloride environment. Along with iron hydroxide phases it was found that corrosion product also contain some organic matter which may be due to adsorption of biofilm on the surface of pipe. Further studies are needed to establish the role of corrosion scales in the mechanism of iron release from corroded pipes.
文摘The Lala Cu deposit in Sichuan Province is one of the most important large deposits in SW China,both in terms of Cu and associated Au-Mo-Co-REE-Fe. Systematic ore petrology study shows that ore minerals are mainly composed of hydrothermal magnetite,chalcopyrite and molybdenite.The wall-rock alterations include biotitization,silicification, carbonatation,albitization,potash feldspathization, apatitation,actinolitation and fluoritation,et al. The Pyrite and magnetite have euhedral-subhedral crystalline grained texture and the chalcopyrite
