Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectivel...Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectively used for the separation and preconcentration of metal ions such as Ni(II), Cu(II), Zn(II) and Cd(II). Critical parameters such as pH, flow rate, sorption capacity, breakthrough studies, distribution coefficient, preconcentration factor, concentration of eluting agents responsible for quantitative extraction of metal ions were optimized. The synthesized resin showed good binding affinity towards Ni(II), Cu(II), Zn(II) and Cd(II) under selective pH conditions. Good breakthrough capacity and fast exchange kinetics of the resin lead to effective separation of metal ions from their binary and ternary mixture by column method on the basis of pH and eluting agents. The resin could be reused for about 8 -10 cycles. The proposed method having the analytical data with the relative standard deviation (RSD) 2% and with recoveries of analytes higher than 98%, reflects upon the reproducibility and reliability of the method which has been successfully applied in the separation and determination of Ni(II), Cu(II), Zn(II) and Cd(II) ions in synthetic, natural and ground water samples.展开更多
Mangrove-derived dissolved organic matter （DOM） has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fring...Mangrove-derived dissolved organic matter （DOM） has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fringed estuarine and coastal areas, dissolved humic substances （DHS） were isolated from one mangrove pore-water sample and one near-shore seawater sample downstream the mangrove pore-water site in the eastern coast of Hainan Island, South China. Fulvic acids, humic acids and XAD-4 fractions were obtained from the two water samples by using a two-column array of XAD-g and XAD-4 resins. Chemica~ and spectroscopic methods were used to analyze the features of these DHS. Compared to the mangrove pore-water DHS, the near-shore seawater DHS were found rich in 13C with lower C/N ratios and more aliphatic compounds and carbohydrates, but less aromatic structures and carboxyl groups. As for the three fractions of the two DHS, XAD-4 fractions contain more aliphatics, carbohydrates, carboxyl groups, and enrich in 13C with respect to both fulvic and humic acids. Photo-oxidation transformation and contribution from marine-derived DOM were considered as the main reasons resulted in the difference in compositional features for these DHS in this study.展开更多
Marine dissolved organic matter(DOM)is one of the largest dynamic pools of organic carbon in the global carbon cycle,yet DOM is still chemically poorly characterized.To better understand the origin,composition,and cyc...Marine dissolved organic matter(DOM)is one of the largest dynamic pools of organic carbon in the global carbon cycle,yet DOM is still chemically poorly characterized.To better understand the origin,composition,and cycling of DOM in the China marginal sea,dissolved humic substances(DHS)were isolated from seawaters in two locations in the Southern Yellow Sea.The DHS were subdivided into fulvic acids(FAs),humic acids(HAs)and the XAD-4 fractions.Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition,Fourier transform infrared spectroscopy(FTIR),~3C cross polarization magic angle spinning(CP/MAS)nuclear magnetic resonance(NMR),and pyrolysis gas chromatography-mass spectrometry(Py-GC/MS).The results demonstrated that both DHS samples encountered the influences from marine source,indicating that algal and microbial-derived materials are the predominant precursors for the studied samples.The three fractions of DHS showed different properties.FAs presented more aromatic features,whereas HAs contained more aliphatic lipids and proteinaceous materials.The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds.The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species,bioavailability of pollutants,mineral weathering and water acidification in marine environments.展开更多
文摘Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectively used for the separation and preconcentration of metal ions such as Ni(II), Cu(II), Zn(II) and Cd(II). Critical parameters such as pH, flow rate, sorption capacity, breakthrough studies, distribution coefficient, preconcentration factor, concentration of eluting agents responsible for quantitative extraction of metal ions were optimized. The synthesized resin showed good binding affinity towards Ni(II), Cu(II), Zn(II) and Cd(II) under selective pH conditions. Good breakthrough capacity and fast exchange kinetics of the resin lead to effective separation of metal ions from their binary and ternary mixture by column method on the basis of pH and eluting agents. The resin could be reused for about 8 -10 cycles. The proposed method having the analytical data with the relative standard deviation (RSD) 2% and with recoveries of analytes higher than 98%, reflects upon the reproducibility and reliability of the method which has been successfully applied in the separation and determination of Ni(II), Cu(II), Zn(II) and Cd(II) ions in synthetic, natural and ground water samples.
基金Supported by the National Natural Science Foundation of China(Nos.40906041,41021064)the State Key Laboratory of Estuarine and Coastal Research (SKLEC) of East China Normal University(Nos.2012KYYW05,201202)
文摘Mangrove-derived dissolved organic matter （DOM） has an important effect on estuarine and coastal area on a large scale. In order to improve the understanding of origin, composition, and fate of DOM in mangrove-fringed estuarine and coastal areas, dissolved humic substances （DHS） were isolated from one mangrove pore-water sample and one near-shore seawater sample downstream the mangrove pore-water site in the eastern coast of Hainan Island, South China. Fulvic acids, humic acids and XAD-4 fractions were obtained from the two water samples by using a two-column array of XAD-g and XAD-4 resins. Chemica~ and spectroscopic methods were used to analyze the features of these DHS. Compared to the mangrove pore-water DHS, the near-shore seawater DHS were found rich in 13C with lower C/N ratios and more aliphatic compounds and carbohydrates, but less aromatic structures and carboxyl groups. As for the three fractions of the two DHS, XAD-4 fractions contain more aliphatics, carbohydrates, carboxyl groups, and enrich in 13C with respect to both fulvic and humic acids. Photo-oxidation transformation and contribution from marine-derived DOM were considered as the main reasons resulted in the difference in compositional features for these DHS in this study.
基金Supported by the National Natural Science Foundation of China(No.41403108)the West Light Foundation of the Chinese Academy of Sciences(No.Y412011004)the Natural Science Foundation of Qinghai Province(No.2014-ZJ-937Q)
文摘Marine dissolved organic matter(DOM)is one of the largest dynamic pools of organic carbon in the global carbon cycle,yet DOM is still chemically poorly characterized.To better understand the origin,composition,and cycling of DOM in the China marginal sea,dissolved humic substances(DHS)were isolated from seawaters in two locations in the Southern Yellow Sea.The DHS were subdivided into fulvic acids(FAs),humic acids(HAs)and the XAD-4 fractions.Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition,Fourier transform infrared spectroscopy(FTIR),~3C cross polarization magic angle spinning(CP/MAS)nuclear magnetic resonance(NMR),and pyrolysis gas chromatography-mass spectrometry(Py-GC/MS).The results demonstrated that both DHS samples encountered the influences from marine source,indicating that algal and microbial-derived materials are the predominant precursors for the studied samples.The three fractions of DHS showed different properties.FAs presented more aromatic features,whereas HAs contained more aliphatic lipids and proteinaceous materials.The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds.The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species,bioavailability of pollutants,mineral weathering and water acidification in marine environments.
