Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)...Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.展开更多
The clinical signs of Tibetan sheep with sulphur- and iron-induced copper deficiency in Maqu County of Gansu Province were defined as thin, decreased appetite, neonatal ataxia, pica, emaciation, and loss of hair color...The clinical signs of Tibetan sheep with sulphur- and iron-induced copper deficiency in Maqu County of Gansu Province were defined as thin, decreased appetite, neonatal ataxia, pica, emaciation, and loss of hair color and anemia. The mineral composition of soil and forage, and samples of liver, blood and hair from Tibetan sheep in affected ranches in this region were compared with those from unaffected areas. The mean concentration of iron in soil and forage in affected pasture was 19 675 ±791 and 1 763 ±197 μg/g, respectively, compared with 8 761 ±871 and 357 ±39 μg/g in unaffected pasture. The mean concentration of sulphur in soil and forage in affected pasture was 1.98% ±0.79% and 0.88% ±0.16%, respectively, compared with 1.16%±0.26% and 0.47%±0.16%in unaffected pasture. The mean copper concentrations in soil and forage from the affected pastures were 15.9±1.8 and 6.7±1.6 μg/g, respectively, compared with 16.7±1.9 and 8.9±2.7 μg/g in unaffected pasture.The mean concentration of Cu in blood, liver, and hair from the affected Tibetan sheep were 0.32±0.12, 51.2±3.1 and 2.16±0.65μg/g, respectively, compared with 0.76±0.21, 191±11 and 3.27±0.96 μg/g for healthy animals. Oral administration of CuClO(OH)3prevented and cured anemia. We conclude that wool eating of Tibetan sheep in this region is probably caused by secondary Cu deficiency, mainly due to the high iron and sulphur contents in soils and forage.展开更多
Currently, 15% of the total Hungarian population is affected by either the elevated arsenic or ammonium concentration of drinking water, and 8% is affected by both compounds. The break-point chlorination is a well-kno...Currently, 15% of the total Hungarian population is affected by either the elevated arsenic or ammonium concentration of drinking water, and 8% is affected by both compounds. The break-point chlorination is a well-known method for ammonium removal, however, during the ammonium-removal process carcinogenic and mutagenic by-products （e.g., THM （trihalogenmethane） and AOX （absorbable organically bound halogens）） may be formed. In order to remove these harmful organic by-products, activated carbon adsorption has to be applied in the technology. The break-point chlorine dose is capable of oxidizing the As3＋ to As5＋. The oxidized form of arsenic can be easily converted to solid phase by adding coagulant （Fe（Ⅲ） or AI（Ⅲ） salt） to the water, and the formed iron/aluminium flocs can be removed by simple rapid sand filtration. Laboratory experiments were performed with raw water from two Hungarian settlements, where the water originated from a deep confined aquifer. In the studied settlements, six wells were in operation, and the supplied drinking water contained ammonium above the maximum allowable concentration, and the arsenic content was around the 10 μg/L standard value. It was found that higher chlorine dose （- 10 Cl2：NH4-N） was needed to achieve the breakpoint than the theoretical value （7.6）. The amount of by-products was also measured during the experiments. The AOX concentrations were significantly higher （21.6 μg/L to 143μg/L） in all cases than the THM concentrations （9-18 μg/L）. The needed coagulant doses were also studied in order to achieve the required arsenic concentrations. Fe（Ⅲ） coagulant was applied in all cases, and it was found that 1-1.5 mg/L Fe（Ⅲ） dose was sufficient to achieve 2-5 μg/L arsenic concentration in the treated water. Based on the results, it can be stated that the breakpoint chlorination combined with Fe（Ⅲ） coagulation is a potential technology to achieve the required ammonium and arsenic concentration at the studied settlements. However, activated carbon has to be installed in order to remove the harmful AOX compounds.展开更多
To reveal the effects of Fe2＋ on bacterial communities in the early stages of minerals dissolution, two different acid mine drainage （AMD） samples were collected at Dabaoshan Mine and Shenbu Mine. Community success...To reveal the effects of Fe2＋ on bacterial communities in the early stages of minerals dissolution, two different acid mine drainage （AMD） samples were collected at Dabaoshan Mine and Shenbu Mine. Community successions of AMD niches were analyzed by Amplified Ribosomal DNA Restriction Analysis （ARDRA）, sequencing, and phylogenetic analysis in original AMD samples and their subculture under Fe2＋ concentrations. Although geochemical properties and community structures were greatly different between the two original AMD samples, bacterial community successions were still very similar under high Fe2＋ concentrations. The results showed that Acidithiobacillus ferrooxidans have competitive relationship with other bacterial species living in the AMD, including species that were also capable of oxidizing ferrous ion. A competitive relationship among different At. ferrooxidans strains likewise existed. Some of At. ferrooxidans can grow first under conditions of high ferrous ion concentration, and other At. ferrooxidans species decreased gradually and disappeared. This suggested that these species of At. ferrooxidans are most acidophilic bacteria and afford Fe3＋ to leach other metallic ion in the early stages of minerals dissolution.展开更多
基金Project(51604131)supported by the National Natural Science Foundation of ChinaProject(2017FB084)supported by the Yunnan Province Applied Basic Research,China+1 种基金Project(KKSY201563041)supported by the Talent&Training Program of Yunnan Province,ChinaProjects(2017T20090159,2018T20150055)supported by the Testing and Analyzing Funds of Kunming University of Science and Technology,China
文摘Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.
基金Supported by the China Agriculture Research System(CARS-35-37)the Guizhou Provincial Science and Technology Foundation Project([2014]6017)
文摘The clinical signs of Tibetan sheep with sulphur- and iron-induced copper deficiency in Maqu County of Gansu Province were defined as thin, decreased appetite, neonatal ataxia, pica, emaciation, and loss of hair color and anemia. The mineral composition of soil and forage, and samples of liver, blood and hair from Tibetan sheep in affected ranches in this region were compared with those from unaffected areas. The mean concentration of iron in soil and forage in affected pasture was 19 675 ±791 and 1 763 ±197 μg/g, respectively, compared with 8 761 ±871 and 357 ±39 μg/g in unaffected pasture. The mean concentration of sulphur in soil and forage in affected pasture was 1.98% ±0.79% and 0.88% ±0.16%, respectively, compared with 1.16%±0.26% and 0.47%±0.16%in unaffected pasture. The mean copper concentrations in soil and forage from the affected pastures were 15.9±1.8 and 6.7±1.6 μg/g, respectively, compared with 16.7±1.9 and 8.9±2.7 μg/g in unaffected pasture.The mean concentration of Cu in blood, liver, and hair from the affected Tibetan sheep were 0.32±0.12, 51.2±3.1 and 2.16±0.65μg/g, respectively, compared with 0.76±0.21, 191±11 and 3.27±0.96 μg/g for healthy animals. Oral administration of CuClO(OH)3prevented and cured anemia. We conclude that wool eating of Tibetan sheep in this region is probably caused by secondary Cu deficiency, mainly due to the high iron and sulphur contents in soils and forage.
文摘Currently, 15% of the total Hungarian population is affected by either the elevated arsenic or ammonium concentration of drinking water, and 8% is affected by both compounds. The break-point chlorination is a well-known method for ammonium removal, however, during the ammonium-removal process carcinogenic and mutagenic by-products （e.g., THM （trihalogenmethane） and AOX （absorbable organically bound halogens）） may be formed. In order to remove these harmful organic by-products, activated carbon adsorption has to be applied in the technology. The break-point chlorine dose is capable of oxidizing the As3＋ to As5＋. The oxidized form of arsenic can be easily converted to solid phase by adding coagulant （Fe（Ⅲ） or AI（Ⅲ） salt） to the water, and the formed iron/aluminium flocs can be removed by simple rapid sand filtration. Laboratory experiments were performed with raw water from two Hungarian settlements, where the water originated from a deep confined aquifer. In the studied settlements, six wells were in operation, and the supplied drinking water contained ammonium above the maximum allowable concentration, and the arsenic content was around the 10 μg/L standard value. It was found that higher chlorine dose （- 10 Cl2：NH4-N） was needed to achieve the breakpoint than the theoretical value （7.6）. The amount of by-products was also measured during the experiments. The AOX concentrations were significantly higher （21.6 μg/L to 143μg/L） in all cases than the THM concentrations （9-18 μg/L）. The needed coagulant doses were also studied in order to achieve the required arsenic concentrations. Fe（Ⅲ） coagulant was applied in all cases, and it was found that 1-1.5 mg/L Fe（Ⅲ） dose was sufficient to achieve 2-5 μg/L arsenic concentration in the treated water. Based on the results, it can be stated that the breakpoint chlorination combined with Fe（Ⅲ） coagulation is a potential technology to achieve the required ammonium and arsenic concentration at the studied settlements. However, activated carbon has to be installed in order to remove the harmful AOX compounds.
文摘To reveal the effects of Fe2＋ on bacterial communities in the early stages of minerals dissolution, two different acid mine drainage （AMD） samples were collected at Dabaoshan Mine and Shenbu Mine. Community successions of AMD niches were analyzed by Amplified Ribosomal DNA Restriction Analysis （ARDRA）, sequencing, and phylogenetic analysis in original AMD samples and their subculture under Fe2＋ concentrations. Although geochemical properties and community structures were greatly different between the two original AMD samples, bacterial community successions were still very similar under high Fe2＋ concentrations. The results showed that Acidithiobacillus ferrooxidans have competitive relationship with other bacterial species living in the AMD, including species that were also capable of oxidizing ferrous ion. A competitive relationship among different At. ferrooxidans strains likewise existed. Some of At. ferrooxidans can grow first under conditions of high ferrous ion concentration, and other At. ferrooxidans species decreased gradually and disappeared. This suggested that these species of At. ferrooxidans are most acidophilic bacteria and afford Fe3＋ to leach other metallic ion in the early stages of minerals dissolution.
