Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with...Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).展开更多
Substitute planting with rapeseed offers promise for safely using large areas of Cd/Pb-contaminated farmland.Cd/Pb distributions during rapeseed oil production were investigated and health risks posed by the oil were ...Substitute planting with rapeseed offers promise for safely using large areas of Cd/Pb-contaminated farmland.Cd/Pb distributions during rapeseed oil production were investigated and health risks posed by the oil were assessed.Tests were performed using three cultivars(Brassica rapa SYH and ZS100 and Brassica napus QY-1)and four oil extraction techniques(mechanical and low-temperature pressing and n-hexane and subcritical low-temperature butane extraction).The amounts of Cd and Pb in oil were 0.73%-8.44%and 3.14%-11.76%,respectively,of the amounts in rapeseed and were strongly affected by the cultivar and oil extraction technique.The heavy metal(HM)concentrations were lower in solvent-extracted oil(particularly subcritical low-temperature butane extracted oil,in which HMs were not detected)than mechanically pressed oil.The Cd and Pb transfer indices were lower(meaning larger proportions of HMs were retained by the rapeseed meal)for B.rapa than B.napus.This was attributed to a high HM binding protein content of B.rapa seed.Health risks to humans were assessed using a probabilistic risk assessment model.The carcinogenic risk was mainly(97.1%-99.9%)caused by Cd and poses more concern than non-carcinogenic risk.Stronger health risks are posed by mechanically pressed than solvent-extracted oil,and higher carcinogenic risks are posed to people living in rural areas than urban areas.Substitute planting with B.rapa and extracting oil with organic solvent(preferably subcritical low-temperature butane)are optimal for safely utilizing Cd/Pb-contaminated soil.Attention should be paid to the health risks posed by Cd in oil to rural populations.展开更多
Water-soluble chitosan(WSC)has been studied for its ability to mobilize soil Pb and promote the phytoremediation by Hylotelephium spectabile in Pb-contaminated fields.We aimed to clarify the internal mechanism by whic...Water-soluble chitosan(WSC)has been studied for its ability to mobilize soil Pb and promote the phytoremediation by Hylotelephium spectabile in Pb-contaminated fields.We aimed to clarify the internal mechanism by which wSC impacts phytoremediation by examining plant growth and Pb accumulation performance of H.spectabile as well as the Pb form,functional groups,and mineral phases of Pb-contaminated soil.WSC effectively decreased soil pH and activated Pb migration in rhizosphere soils,with a considerable increase in water-soluble and acid-extractable Pb by 29%-102%and 9%-65%,respectively,and a clear decreasing trend in reducible and oxidizable Pb.Fourier-transform infrared spectroscopy revealed a significant increase in amino and hydroxyl groups in the soil generated by WSC.The coordination of Pb with amino and hydroxyl groups may play an important role in the formation of Pb complexes and activation of Pb in soil.In field trials,the application of WSC significantly increased Pb accumulation in H.spectabile by 125.44%,reaching 92 g/hm^(2).Moreover,the organic matter and nitrogen in the soils were increased by WSc,which improved the growth conditions of H.spectabile.No obvious growth inhibition was observed in either the pot or field trials.Therefore,WSC is a promising chelating agent for mobilizing Pb in soil.Additionally,WSC can be potentially used to boost H.spectabil-mediated phytoremediation of Pb-contaminatedfarmland.展开更多
基金supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park (Project HZQBKCZYB-2020030)National Key R&D Program of China (Project 2017YFA0204403)+2 种基金the National Natural Science Foundation of China (Project 51590892)the Major Program of Changsha Science and Technology (Project kh2003023)the Innovation and Technology Commission of HKSAR through Hong Kong Branch of National Precious Metals Material Engineering Research Centre,and the City University of Hong Kong (Project 9667207)。
文摘Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).
基金the National Natural Science Foundation of China(Nos.41907125 and 41771509)China Postdoctoral Science Foundation(No.2019M650827).
文摘Substitute planting with rapeseed offers promise for safely using large areas of Cd/Pb-contaminated farmland.Cd/Pb distributions during rapeseed oil production were investigated and health risks posed by the oil were assessed.Tests were performed using three cultivars(Brassica rapa SYH and ZS100 and Brassica napus QY-1)and four oil extraction techniques(mechanical and low-temperature pressing and n-hexane and subcritical low-temperature butane extraction).The amounts of Cd and Pb in oil were 0.73%-8.44%and 3.14%-11.76%,respectively,of the amounts in rapeseed and were strongly affected by the cultivar and oil extraction technique.The heavy metal(HM)concentrations were lower in solvent-extracted oil(particularly subcritical low-temperature butane extracted oil,in which HMs were not detected)than mechanically pressed oil.The Cd and Pb transfer indices were lower(meaning larger proportions of HMs were retained by the rapeseed meal)for B.rapa than B.napus.This was attributed to a high HM binding protein content of B.rapa seed.Health risks to humans were assessed using a probabilistic risk assessment model.The carcinogenic risk was mainly(97.1%-99.9%)caused by Cd and poses more concern than non-carcinogenic risk.Stronger health risks are posed by mechanically pressed than solvent-extracted oil,and higher carcinogenic risks are posed to people living in rural areas than urban areas.Substitute planting with B.rapa and extracting oil with organic solvent(preferably subcritical low-temperature butane)are optimal for safely utilizing Cd/Pb-contaminated soil.Attention should be paid to the health risks posed by Cd in oil to rural populations.
基金The research was financially supported by the National Natural Science Foundation of China(Nos.42277237,22206149,and 41907125)the Applied Basic Research Project of Shanxi Province(China)(No.20210302124220)the Horizontal Scientific Research Funds of Taiyuan University of Technology(Nos.RH2200002532 and RH2300002821).
文摘Water-soluble chitosan(WSC)has been studied for its ability to mobilize soil Pb and promote the phytoremediation by Hylotelephium spectabile in Pb-contaminated fields.We aimed to clarify the internal mechanism by which wSC impacts phytoremediation by examining plant growth and Pb accumulation performance of H.spectabile as well as the Pb form,functional groups,and mineral phases of Pb-contaminated soil.WSC effectively decreased soil pH and activated Pb migration in rhizosphere soils,with a considerable increase in water-soluble and acid-extractable Pb by 29%-102%and 9%-65%,respectively,and a clear decreasing trend in reducible and oxidizable Pb.Fourier-transform infrared spectroscopy revealed a significant increase in amino and hydroxyl groups in the soil generated by WSC.The coordination of Pb with amino and hydroxyl groups may play an important role in the formation of Pb complexes and activation of Pb in soil.In field trials,the application of WSC significantly increased Pb accumulation in H.spectabile by 125.44%,reaching 92 g/hm^(2).Moreover,the organic matter and nitrogen in the soils were increased by WSc,which improved the growth conditions of H.spectabile.No obvious growth inhibition was observed in either the pot or field trials.Therefore,WSC is a promising chelating agent for mobilizing Pb in soil.Additionally,WSC can be potentially used to boost H.spectabil-mediated phytoremediation of Pb-contaminatedfarmland.