Electrochemical CO_(2)reduction(ECR)powered by renewable energy sources provides a sustainable avenue to producing carbon-neutral fuels and chemicals.The design and development of high performance,cost-effective,and s...Electrochemical CO_(2)reduction(ECR)powered by renewable energy sources provides a sustainable avenue to producing carbon-neutral fuels and chemicals.The design and development of high performance,cost-effective,and stable catalysts for ECR remain a focus of intense research.Here,we report a novel electrocatalyst,two-dimensional cadmium-based 1,4-benzenedicarboxylate metal-organic frameworks(Cd-BDC MOFs)which can effectively convert CO_(2)to CO with a faradaic efficiency(FE)of more than80.0%over the voltage range between-0.9 and-1.1 V(versus reversible hydrogen electrode,vs.RHE)in 0.1 mol·L^(-1) CO_(2)-saturated KHCO_(3)solution with an H-type cell,reaching up to 88.9%at-1.0 V(vs.RHE).The performance outperforms commercial CdO and many other MOF-based materials demonstrated in prior literature.The catalytic property can be readily tuned by manipulating synthesis conditions as well as electrolyte type.Especially,high CO FEs exceeding 90.0%can be attained on the Cd-BDC electrode at potentials ranging from-0.16 to-1.06 V(vs.RHE)in 0.5 mol·L^(-1) KHCO_(3)solution by using a gas diffusion electrode cell system.The maximum CO FE approaches~97.6%at-0.26 V(vs.RHE)and the CO partial geometric current density is as high as about 108.1 mA·cm^(-2) at-1.1 V(vs.RHE).This work offers an efficient,low cost,and alternative electrocatalyst for CO_(2)transformation.展开更多
Zinc neutral leaching residue（ZNLR） from hydrometallurgical zinc smelting processing can be determined as hazardous intermediate containing considerable amounts of Cd and Zn which have great threats to the environme...Zinc neutral leaching residue（ZNLR） from hydrometallurgical zinc smelting processing can be determined as hazardous intermediate containing considerable amounts of Cd and Zn which have great threats to the environment. The ZNLR contained approximately 35.99% Zn, 15.93% Fe and 0.26% Cd, and Cd mainly existed as ferrites in the ZNLR in this research. Reductive acid leaching of ZNLR was investigated. The effects of hydrazine sulfate concentration, initial sulfuric acid concentration, temperature, duration and liquid-to-solid ratio on the extraction of Cd, Zn and Fe were examined. The extraction efficiencies of Cd, Zn and Fe reached 90.81%, 95.83% and 94.19%, respectively when the leaching parameters were fixed as follows： hydrazine sulfate concentration, 33.3 g/L; sulfuric acid concentration, 80 g/L; temperature, 95 °C; duration of leaching, 120 min; liquid-to-solid ratio, 10 m L/g and agitation, 400 r/min. XRD and SEM-EDS analyses of the leaching residue confirmed that lead sulfate（Pb SO4） and hydrazinium zinc sulfate（（N2H5）2Zn（SO4）2） were the main phases remaining in the reductive leaching residue.展开更多
The effectiveness and longevity of amendments will influence the reduction in cadmium(Cd) bioavailability by in situ remediation techniques. Different amendments, including red mud(RM), corn straw(CS), rape straw(RS),...The effectiveness and longevity of amendments will influence the reduction in cadmium(Cd) bioavailability by in situ remediation techniques. Different amendments, including red mud(RM), corn straw(CS), rape straw(RS), and their combinations with zinc(Zn) fertilizer, were evaluated based on a long-term field experiment. It was found that all amendments decreased the concentration of available-Cd(EDTA-Cd and Exch-Cd) in soil and also reduced the Cd content(%) in plants. The amendments were still effective after eight years, although the effect did decline over time. The reduction of plant Cd content was 83.5% for red mud plus rape straw(RMRS), 65.3% for red mud plus corn straw(RMCS), 50.9% for RS, 54.0% for RM, and 37.3% for CS in the first few years. The reduction in plant Cd content was still 17.2% for RMRS after eight years, and RMRS was found to be the most effective treatment for decreasing Cd bioavailability. This study also explained that why the reduction in plant Cd content declined over time is the change of available Cd content in soil over time, which is important for guiding agricultural practice. It was concluded that RM, CS, RS, and their combinations with Zn fertilizer as effective amendments can have a profound and lasting positive impact on Cd-contaminated soils.展开更多
We investigated the reduction of lepidocrocite(γ-FeOOH) by Shewanella oneidensis MR-1 in the presence and absence of Cd. The results showed that Cd^(2+) retarded microbial reduction of γ-Fe OOH and avoided formation...We investigated the reduction of lepidocrocite(γ-FeOOH) by Shewanella oneidensis MR-1 in the presence and absence of Cd. The results showed that Cd^(2+) retarded microbial reduction of γ-Fe OOH and avoided formation of magnetite. The inhibitory effect on γ-Fe OOH transformation may not result from Cd^(2+) toxicity to the bacterium; it rather was probably due to competitive adsorption between Cd^(2+) and Fe^(2+) on γ-Fe OOH as its surface reduction catalyzed by adsorbed Fe^(2+) was eliminated by adsorption of Cd^(2+).展开更多
使用酚二磺酸法、还原蒸馏法、镀铜镉还原-重氮化偶合比色法和改进紫外分光光度法(校正因数法)测定了中国9种不同类型土壤的硝态氮含量,分析了改进紫外分光光度法与其余三种测定方法的差异及其适用性。统计分析表明对于有机质含量低于50...使用酚二磺酸法、还原蒸馏法、镀铜镉还原-重氮化偶合比色法和改进紫外分光光度法(校正因数法)测定了中国9种不同类型土壤的硝态氮含量,分析了改进紫外分光光度法与其余三种测定方法的差异及其适用性。统计分析表明对于有机质含量低于50 g kg-1的矿质土壤,可以使用2.2作为校正因数,四种分析方法的测定值具有极显著的相关性,尤其是紫外分光光度法与酚二磺酸法的测定结果最为接近,没有极显著差异;对于有机质含量接近和高于50 g kg-1的土壤,校正因数还需要修改。紫外分光光度法具有操作简单、测定速度快等优点,适用于批量快速测定。展开更多
基金supported by the National Natural Science Foundation of China(No.21972010)Beijing Natural Science Foundation(No.2192039)+1 种基金Beijing University of Chemical Technology(XK180301)the Foundation of Key Laboratory of LowCarbon Conversion Science&Engineering,Shanghai Advanced Research Institute,Chinese Academy of Sciences(No.KLLCCSE201901,SARI,CAS)。
文摘Electrochemical CO_(2)reduction(ECR)powered by renewable energy sources provides a sustainable avenue to producing carbon-neutral fuels and chemicals.The design and development of high performance,cost-effective,and stable catalysts for ECR remain a focus of intense research.Here,we report a novel electrocatalyst,two-dimensional cadmium-based 1,4-benzenedicarboxylate metal-organic frameworks(Cd-BDC MOFs)which can effectively convert CO_(2)to CO with a faradaic efficiency(FE)of more than80.0%over the voltage range between-0.9 and-1.1 V(versus reversible hydrogen electrode,vs.RHE)in 0.1 mol·L^(-1) CO_(2)-saturated KHCO_(3)solution with an H-type cell,reaching up to 88.9%at-1.0 V(vs.RHE).The performance outperforms commercial CdO and many other MOF-based materials demonstrated in prior literature.The catalytic property can be readily tuned by manipulating synthesis conditions as well as electrolyte type.Especially,high CO FEs exceeding 90.0%can be attained on the Cd-BDC electrode at potentials ranging from-0.16 to-1.06 V(vs.RHE)in 0.5 mol·L^(-1) KHCO_(3)solution by using a gas diffusion electrode cell system.The maximum CO FE approaches~97.6%at-0.26 V(vs.RHE)and the CO partial geometric current density is as high as about 108.1 mA·cm^(-2) at-1.1 V(vs.RHE).This work offers an efficient,low cost,and alternative electrocatalyst for CO_(2)transformation.
基金Project(2012FJ1010)supported by the Key Project of Science and Technology of Hunan ProvinceChina+2 种基金Project(51474247)supported by the National Natural Science Foundation of ChinaProject(2012GS430201)supported by the Science and Technology Program for Public WellbeingChina
文摘Zinc neutral leaching residue（ZNLR） from hydrometallurgical zinc smelting processing can be determined as hazardous intermediate containing considerable amounts of Cd and Zn which have great threats to the environment. The ZNLR contained approximately 35.99% Zn, 15.93% Fe and 0.26% Cd, and Cd mainly existed as ferrites in the ZNLR in this research. Reductive acid leaching of ZNLR was investigated. The effects of hydrazine sulfate concentration, initial sulfuric acid concentration, temperature, duration and liquid-to-solid ratio on the extraction of Cd, Zn and Fe were examined. The extraction efficiencies of Cd, Zn and Fe reached 90.81%, 95.83% and 94.19%, respectively when the leaching parameters were fixed as follows： hydrazine sulfate concentration, 33.3 g/L; sulfuric acid concentration, 80 g/L; temperature, 95 °C; duration of leaching, 120 min; liquid-to-solid ratio, 10 m L/g and agitation, 400 r/min. XRD and SEM-EDS analyses of the leaching residue confirmed that lead sulfate（Pb SO4） and hydrazinium zinc sulfate（（N2H5）2Zn（SO4）2） were the main phases remaining in the reductive leaching residue.
基金financial support from the National Key Research and Development Program of China(2016YFD0800406)。
文摘The effectiveness and longevity of amendments will influence the reduction in cadmium(Cd) bioavailability by in situ remediation techniques. Different amendments, including red mud(RM), corn straw(CS), rape straw(RS), and their combinations with zinc(Zn) fertilizer, were evaluated based on a long-term field experiment. It was found that all amendments decreased the concentration of available-Cd(EDTA-Cd and Exch-Cd) in soil and also reduced the Cd content(%) in plants. The amendments were still effective after eight years, although the effect did decline over time. The reduction of plant Cd content was 83.5% for red mud plus rape straw(RMRS), 65.3% for red mud plus corn straw(RMCS), 50.9% for RS, 54.0% for RM, and 37.3% for CS in the first few years. The reduction in plant Cd content was still 17.2% for RMRS after eight years, and RMRS was found to be the most effective treatment for decreasing Cd bioavailability. This study also explained that why the reduction in plant Cd content declined over time is the change of available Cd content in soil over time, which is important for guiding agricultural practice. It was concluded that RM, CS, RS, and their combinations with Zn fertilizer as effective amendments can have a profound and lasting positive impact on Cd-contaminated soils.
基金financially supported by the National Natural Science Foundation of China(41601239)the Highlevel Leading Talent Introduction Program of GDAS,the China Postdoctoral Science Foundation(2016M600644)the"Pearl River Talents"Postdoctoral Program of Guangdong Province,and the National Key Research and Development Program of China(2016YFD0800703)
文摘We investigated the reduction of lepidocrocite(γ-FeOOH) by Shewanella oneidensis MR-1 in the presence and absence of Cd. The results showed that Cd^(2+) retarded microbial reduction of γ-Fe OOH and avoided formation of magnetite. The inhibitory effect on γ-Fe OOH transformation may not result from Cd^(2+) toxicity to the bacterium; it rather was probably due to competitive adsorption between Cd^(2+) and Fe^(2+) on γ-Fe OOH as its surface reduction catalyzed by adsorbed Fe^(2+) was eliminated by adsorption of Cd^(2+).
文摘使用酚二磺酸法、还原蒸馏法、镀铜镉还原-重氮化偶合比色法和改进紫外分光光度法(校正因数法)测定了中国9种不同类型土壤的硝态氮含量,分析了改进紫外分光光度法与其余三种测定方法的差异及其适用性。统计分析表明对于有机质含量低于50 g kg-1的矿质土壤,可以使用2.2作为校正因数,四种分析方法的测定值具有极显著的相关性,尤其是紫外分光光度法与酚二磺酸法的测定结果最为接近,没有极显著差异;对于有机质含量接近和高于50 g kg-1的土壤,校正因数还需要修改。紫外分光光度法具有操作简单、测定速度快等优点,适用于批量快速测定。
