Flos Sophorae and Fructus Sophorae are two kinds of traditional Chinese medicines. In this work, the two kinds of traditional Chinese medicines collected from eleven areas of Dezhou, were analyzed by inductively coupl...Flos Sophorae and Fructus Sophorae are two kinds of traditional Chinese medicines. In this work, the two kinds of traditional Chinese medicines collected from eleven areas of Dezhou, were analyzed by inductively couple plasma-mass spectrometry （ICP-MS） to compare the content and distribution of 14 kinds of rare earth elements （REEs）. The method was verified by analyzing GBW07605 certified reference material. The results showed that ICP-MS is an accurate, sensitive and reliable technique for determining REEs in traditional Chinese medicine. There were big differences in contents for REEs in Flos Sophorae and Fmctus Sophorae from different areas. The contents of total REEs in Flos Sophorae samples from different areas ranged from 1.0785 to 2.2659 μg/g, while those in Fmctus Sophorae from 0.6826 to 1.0527 ktg/g. The contents of total REEs in Flos Sophorae samples from different areas were obviously higher than those in Fmctus Sophorae of the same area and there was big difference between various Flos Sophorae samples. Interestingly, the higher the content of total REEs in Flos Sophorae samples, the lower the content of total REEs in Fmctus Sophorae samples of the same area. The plots of normalized element concentration versus atomic number showed some characteristic distribution trends. The distribution trend of light REEs （La-Gd） was relatively fiat except a positive Eu anomaly, however, that was steep and discrepant for heavy REEs （Tb-Lu）. The results could provide a valuable reference for understanding the relationship between the curative mechanism, pharmacology characteristics and their geological condition for the two traditional Chinese medicines investigated.展开更多
This study examined the biochemical responses of wheat（Triticum aestivum） to the stress of rare earth yttrium（Y） and showed that 25–100 mg/kg Y treatments evidently increased the biomass（root mass,shoot mass and...This study examined the biochemical responses of wheat（Triticum aestivum） to the stress of rare earth yttrium（Y） and showed that 25–100 mg/kg Y treatments evidently increased the biomass（root mass,shoot mass and leaf mass）,accompanied by a significant（p0.05） increase in the chlorophyll（CHL） content in wheat leaves.Increased malondialdehyde（MDA） levels were detected in wheat shoots（stem and leaf） and roots too,indicating the presence of poisoning active oxygen species（AOS）.The MDA content in wheat roots increased with the augmentation of Y concentration.These results indicated that there was a dose-dependent effect of Y on the changes of MDA content in wheat roots.Although the activities of superoxide dismutases（SOD）,peroxidases（POD） and catalases（CAT） in wheat shoots and roots irregularly fluctuated with the increase in Y concentration,25–100 mg/kg Y significantly（p0.01） increased the activities of SOD and POD.In general,the dose-dependent effects of Y on the activity of antioxidant enzymes were insignificant.Our data also indicated that the increase in SOD and POD activities could be used as a good biomarker for the stress induced by low concentrations of Y.展开更多
The Agrobacterium sp.HN1 was isolated from the soil and used to adsorb rare earth ions La3＋ and Ce3＋.The results showed that the pretreatments of Agrobacterium sp.HN1 did not enhance the adsorption of La3＋ and Ce3...The Agrobacterium sp.HN1 was isolated from the soil and used to adsorb rare earth ions La3＋ and Ce3＋.The results showed that the pretreatments of Agrobacterium sp.HN1 did not enhance the adsorption of La3＋ and Ce3＋.The pH,temperature,time and bacterial age affected the dynamics of adsorption of La3＋ and Ce3＋.The optimum adsorption conditions for Agrobacterium sp.HN1 were as follows：15 mg/L La3＋ of initial concentration,10 mg/L Ce3＋,300 mg/L（dry wt.cell） biomass for sorption,6.8 pH,30 oC temperature,150 r/min rotational speed,2 h adsorption time and 28 h bacterial age.The adsorption kinetics of La3＋ and Ce3＋ for Agrobacterium sp.HN1 followed the pseudo-second order equation.展开更多
Viciafaba L. seedlings were hydroponically cultivated in 0-12 mg/L of extraneous lanthanum （La） for 15 d to investigate ecotoxicological effects and risk assessment of rare earth elements （REEs）. The results showe...Viciafaba L. seedlings were hydroponically cultivated in 0-12 mg/L of extraneous lanthanum （La） for 15 d to investigate ecotoxicological effects and risk assessment of rare earth elements （REEs）. The results showed that reactive oxygen species （ROS） production such as superoxide radical （O2） and hydrogen peroxide （H202） were overproduced at higher concentrations of La, resulting in oxidatively modi- fied proteins and shoot growth retardation. While, superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX） and guaiacol peroxidase （GPX） isoenzymes were elevated to some extent to eliminate excess of ROS. HSP70 production and endopeptidase isoenzymes were also enhanced, which were involved in repairing or degradation of the oxidatively modified proteins due to La. Thus, the antioxidant isoenzymes, endoprotease isoenzymes and HSP70 worked cooperatively to alleviate the La-induced oxidative damage. The significant en- hancement of CAT and APX isoenzymes and HSP70 could also be used as early bioindicators of La-polluted solution. The threshold dose range was firstly delimited as 1-2 mg/L of extraneous La, corresponding to 7.34-9.37 μg/g dry weight in the leaves. These results would be helpful to further understand the toxicological effects and possible mechanisms of REE（s） on crop seedlings.展开更多
Content and distribution patterns of rare earth dements （REEs） in the suspended particulate material （SPM） of Daliao River system were investigated and compared with those in the fiver and sea sediments, loess, an...Content and distribution patterns of rare earth dements （REEs） in the suspended particulate material （SPM） of Daliao River system were investigated and compared with those in the fiver and sea sediments, loess, and soils of China. Twenty-seven samples of SPM were taken in Daliao River system and digested with various acids followed by ICP-MS analysis for REEs and ICP-OES analysis for Al, Fe, Mn, Ti, Mg, Ca, Na, and K, to measure the total concentrations of these elements. Results indicated that the spatial change in the content of REEs was great, with the coefficient of variance （CV） from 84% to 105%, while the contents of REEs were significantly correlated with each other. Chondrite-normalized patterns of REEs were characterized by higher enrichment of light REEs than heavy REEs, and a depletion of Eu in the SPM was generally found. The positive anomaly of Eu in the SPM of Xi River was due to anthropogenic source in Shenyang City. Furthermore, chondfite- and upper continent crust-normalized patterns of REEs in the SPM of Daliao River system, sediments of Yangtze River and Yellow River, sediments of Yellow Sea, East Sea, South Sea of China, and loess and soil of China, were very similar to one another. These demonstrated that the weathering and sedimentary processes resulted in constant REE distribution not only in the typical sedimentary rocks, but also in the modem riverine particle, sea sediments, loess, and soils.展开更多
This study described a hydrometallurgical method to investigate the separation of rare earth elements（REEs）from rare earth polishing powder wastes（REPPWs）containing large amounts of rare earth oxides with a major ...This study described a hydrometallurgical method to investigate the separation of rare earth elements（REEs）from rare earth polishing powder wastes（REPPWs）containing large amounts of rare earth oxides with a major phase of CeO2 and minor phases of La2O3,Pr2O3,and Nd2O3 using a process devised by the authors.The suggested approach consisted of five processes：the synthesis of NaR E（SO4）2·xH2O from rare earth oxides in Na2SO4-H2SO4-H2 O solutions（Process 1）,the conversion of NaR E（SO4）2·xH2O into RE（OH）3 using NaO H（Process 2）,and the oxidation of Ce（OH）3 into Ce（OH）4 using air with O2 injection（Process 3）,followed by Processes 4 and 5 for separation of REEs by acid leaching using HCl and H2SO4,respectively.To confirm the high yield of NaR E（SO4）2·xH2O in Process 1,experiments were carried out under various Na2SO4 concentrations（0.4–2.5 mol/L）,sulfuric acid concentrations（6–14 mol/L）,and reaction temperatures（95–125 oC）.In addition,the effect of the pH value on the separation of Ce（OH）4 in HCl-H2 O solutions with Ce（OH）4,La-,Pr-,and Nd（OH）3 in Process 4 was also investigated.On the basis of above results,the possibility of effective separation of REEs from REPPWs could be confirmed.展开更多
Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on impor...Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on import as domestic production of REEs was ceased because of the environmental concerns during mining and lack of competitiveness. Nonetheless, unconventional REEs-containing resources,including produced water. acid mine drainage, and coal and coal byproducts（C＆CBs） contain significant amounts of REEs. However, the concentrations of REEs in these resources are several orders of magnitude lower than that of REEs ores. Thus, extraction of REEs from these materials is challenging. Here we report REEs extraction with environmentally friendly method that successfully concentrated REEs from312 ppm in fly ash to 99.4% in the final product. Especially, the five critically important REEs（Dy, Eu, Nd.Tb. and Y） account for up to ～63% of the total weight of all REEs in the final 99.4%-purity product. Coal fly ash is one of the major solid coal utilization byproducts, representing great potential resources for REEs extraction. Extraction of REEs from these unconventional resources could be the way to secure domestic supply of these critical materials.展开更多
The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncer...The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments.展开更多
Solvent extraction kinetics of Sm（Ⅲ）, Eu（Ⅲ） and Gd（Ⅲ） from hydrochloric acid have been focused on using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester （P507） with Anordning for Kontinuerlig Undersokning av...Solvent extraction kinetics of Sm（Ⅲ）, Eu（Ⅲ） and Gd（Ⅲ） from hydrochloric acid have been focused on using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester （P507） with Anordning for Kontinuerlig Undersokning av Fordelningsfaktore rid Vatske Extraction （AKUFVE）. Compared with the conventional set-up, some advantages emerge obviously, for example, fast phase separation, easy operation and convenience of kinetic data acquisition. First of all, the extraction mechanism was discussed based on the dimeric model of P507. Secondly, the effects of stirring speed were investigated and 420 r-min-1 was determined of the following experiments. The effects of pH, concentration of rare earth elements （REEs） and P507 on the extraction rate were analyzed. The results indicated that the extraction mechanism changed with the increasing concentration of P507. Then, the experiments with different temperature were carried out. It turned out that the values of apparent activation energy （Ea） for Sm（Ⅲ）, Eu（Ⅲ） and Gd（Ⅲ） extracted by P507 were 26.80 kJ-mol-1, 13.40 kJ.mol-1 and 1.10 kJ- mol- 1 respectively, the resistance of the entire process was limited by diffusion or both of diffusion and reaction. Finally, the correlation equations were obtained, and the theoretical results fit with the experimental data well, most relative error was within ± 30%.展开更多
A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower...A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3–785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations(∑REE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow(SHF), normal flow(NF), low flow(LF) and high flow(HF) season, respectively. The R_(( L/M)) and R_((H/M)) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEsenrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fl uctuate and positively correlate to salinity in estuary, probably because of the geochemical behavior differences between Y and Ho.展开更多
The material sources and control factors of rare earth elemems （REEs） for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying （borehole number： ZK10-6）, Sichuan Province, South China...The material sources and control factors of rare earth elemems （REEs） for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying （borehole number： ZK10-6）, Sichuan Province, South China, were investigated. All samples were determined by inductively coupled plasma mass spectrometry （ICP-MS）. The chondrite-normalized distribution patterns of mudstone samples are uniform. All samples belong to the light rare earth element （LREE）-rich type and are enriched in LREEs relative to heavy rare earth elements （HREEs）. The distribution curves of REEs in mudstone are highly similar to Mount Emei basalt and the three periods of REEs enrichment correspond to three Mount Emei basalt eruption cycles in Longtan period. The results indicate that REE patterns are not controlled by materials from the seawater or land plants. The predominant sources of REEs are from terrigenous material as indicated by negative Eu anomaly. So, the sources of REEs are controlled by terrigenous material, and the Mount Emei basalt is the predominant source of terrigenous material. Thus, transgression-regression is another control factor of REEs enrichment.展开更多
基金Project supported by the Scientific Project of the Dezhou Government (2006067)the Science Fundation of Shandong Province (Q2008B08)the Key Technologies R&D Programme of Shandong Province (2010GSF10615)
文摘Flos Sophorae and Fructus Sophorae are two kinds of traditional Chinese medicines. In this work, the two kinds of traditional Chinese medicines collected from eleven areas of Dezhou, were analyzed by inductively couple plasma-mass spectrometry （ICP-MS） to compare the content and distribution of 14 kinds of rare earth elements （REEs）. The method was verified by analyzing GBW07605 certified reference material. The results showed that ICP-MS is an accurate, sensitive and reliable technique for determining REEs in traditional Chinese medicine. There were big differences in contents for REEs in Flos Sophorae and Fmctus Sophorae from different areas. The contents of total REEs in Flos Sophorae samples from different areas ranged from 1.0785 to 2.2659 μg/g, while those in Fmctus Sophorae from 0.6826 to 1.0527 ktg/g. The contents of total REEs in Flos Sophorae samples from different areas were obviously higher than those in Fmctus Sophorae of the same area and there was big difference between various Flos Sophorae samples. Interestingly, the higher the content of total REEs in Flos Sophorae samples, the lower the content of total REEs in Fmctus Sophorae samples of the same area. The plots of normalized element concentration versus atomic number showed some characteristic distribution trends. The distribution trend of light REEs （La-Gd） was relatively fiat except a positive Eu anomaly, however, that was steep and discrepant for heavy REEs （Tb-Lu）. The results could provide a valuable reference for understanding the relationship between the curative mechanism, pharmacology characteristics and their geological condition for the two traditional Chinese medicines investigated.
基金supported by National Natural Science Foundation of China(21067003,51364015)the Natural Science Foundation of Jiangxi Province(20114BAB203024)the National High-Tech Research and Development Program of China(2012BAC11B07)
文摘This study examined the biochemical responses of wheat（Triticum aestivum） to the stress of rare earth yttrium（Y） and showed that 25–100 mg/kg Y treatments evidently increased the biomass（root mass,shoot mass and leaf mass）,accompanied by a significant（p0.05） increase in the chlorophyll（CHL） content in wheat leaves.Increased malondialdehyde（MDA） levels were detected in wheat shoots（stem and leaf） and roots too,indicating the presence of poisoning active oxygen species（AOS）.The MDA content in wheat roots increased with the augmentation of Y concentration.These results indicated that there was a dose-dependent effect of Y on the changes of MDA content in wheat roots.Although the activities of superoxide dismutases（SOD）,peroxidases（POD） and catalases（CAT） in wheat shoots and roots irregularly fluctuated with the increase in Y concentration,25–100 mg/kg Y significantly（p0.01） increased the activities of SOD and POD.In general,the dose-dependent effects of Y on the activity of antioxidant enzymes were insignificant.Our data also indicated that the increase in SOD and POD activities could be used as a good biomarker for the stress induced by low concentrations of Y.
基金supported by the Natural Science Research Program of Henan Province,China(2007180025)
文摘The Agrobacterium sp.HN1 was isolated from the soil and used to adsorb rare earth ions La3＋ and Ce3＋.The results showed that the pretreatments of Agrobacterium sp.HN1 did not enhance the adsorption of La3＋ and Ce3＋.The pH,temperature,time and bacterial age affected the dynamics of adsorption of La3＋ and Ce3＋.The optimum adsorption conditions for Agrobacterium sp.HN1 were as follows：15 mg/L La3＋ of initial concentration,10 mg/L Ce3＋,300 mg/L（dry wt.cell） biomass for sorption,6.8 pH,30 oC temperature,150 r/min rotational speed,2 h adsorption time and 28 h bacterial age.The adsorption kinetics of La3＋ and Ce3＋ for Agrobacterium sp.HN1 followed the pseudo-second order equation.
基金supported by the National"863"High Tech Development Plan(2008ZX07103,2008ZX07010)the National Natural Science Foundation of China(20877032)the Natural Science Foundation of Anhui Province(090413083)
文摘Viciafaba L. seedlings were hydroponically cultivated in 0-12 mg/L of extraneous lanthanum （La） for 15 d to investigate ecotoxicological effects and risk assessment of rare earth elements （REEs）. The results showed that reactive oxygen species （ROS） production such as superoxide radical （O2） and hydrogen peroxide （H202） were overproduced at higher concentrations of La, resulting in oxidatively modi- fied proteins and shoot growth retardation. While, superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX） and guaiacol peroxidase （GPX） isoenzymes were elevated to some extent to eliminate excess of ROS. HSP70 production and endopeptidase isoenzymes were also enhanced, which were involved in repairing or degradation of the oxidatively modified proteins due to La. Thus, the antioxidant isoenzymes, endoprotease isoenzymes and HSP70 worked cooperatively to alleviate the La-induced oxidative damage. The significant en- hancement of CAT and APX isoenzymes and HSP70 could also be used as early bioindicators of La-polluted solution. The threshold dose range was firstly delimited as 1-2 mg/L of extraneous La, corresponding to 7.34-9.37 μg/g dry weight in the leaves. These results would be helpful to further understand the toxicological effects and possible mechanisms of REE（s） on crop seedlings.
基金the National Basic Key Research Program of China (2004CB418502)the National Natural Science Foundation of China (40671002)
文摘Content and distribution patterns of rare earth dements （REEs） in the suspended particulate material （SPM） of Daliao River system were investigated and compared with those in the fiver and sea sediments, loess, and soils of China. Twenty-seven samples of SPM were taken in Daliao River system and digested with various acids followed by ICP-MS analysis for REEs and ICP-OES analysis for Al, Fe, Mn, Ti, Mg, Ca, Na, and K, to measure the total concentrations of these elements. Results indicated that the spatial change in the content of REEs was great, with the coefficient of variance （CV） from 84% to 105%, while the contents of REEs were significantly correlated with each other. Chondrite-normalized patterns of REEs were characterized by higher enrichment of light REEs than heavy REEs, and a depletion of Eu in the SPM was generally found. The positive anomaly of Eu in the SPM of Xi River was due to anthropogenic source in Shenyang City. Furthermore, chondfite- and upper continent crust-normalized patterns of REEs in the SPM of Daliao River system, sediments of Yangtze River and Yellow River, sediments of Yellow Sea, East Sea, South Sea of China, and loess and soil of China, were very similar to one another. These demonstrated that the weathering and sedimentary processes resulted in constant REE distribution not only in the typical sedimentary rocks, but also in the modem riverine particle, sea sediments, loess, and soils.
文摘This study described a hydrometallurgical method to investigate the separation of rare earth elements（REEs）from rare earth polishing powder wastes（REPPWs）containing large amounts of rare earth oxides with a major phase of CeO2 and minor phases of La2O3,Pr2O3,and Nd2O3 using a process devised by the authors.The suggested approach consisted of five processes：the synthesis of NaR E（SO4）2·xH2O from rare earth oxides in Na2SO4-H2SO4-H2 O solutions（Process 1）,the conversion of NaR E（SO4）2·xH2O into RE（OH）3 using NaO H（Process 2）,and the oxidation of Ce（OH）3 into Ce（OH）4 using air with O2 injection（Process 3）,followed by Processes 4 and 5 for separation of REEs by acid leaching using HCl and H2SO4,respectively.To confirm the high yield of NaR E（SO4）2·xH2O in Process 1,experiments were carried out under various Na2SO4 concentrations（0.4–2.5 mol/L）,sulfuric acid concentrations（6–14 mol/L）,and reaction temperatures（95–125 oC）.In addition,the effect of the pH value on the separation of Ce（OH）4 in HCl-H2 O solutions with Ce（OH）4,La-,Pr-,and Nd（OH）3 in Process 4 was also investigated.On the basis of above results,the possibility of effective separation of REEs from REPPWs could be confirmed.
基金Project supported by the Department of Energy through"Rare Earth Elements From Coal and Coal By-Products"program(DE-FE00027069)
文摘Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on import as domestic production of REEs was ceased because of the environmental concerns during mining and lack of competitiveness. Nonetheless, unconventional REEs-containing resources,including produced water. acid mine drainage, and coal and coal byproducts（C＆CBs） contain significant amounts of REEs. However, the concentrations of REEs in these resources are several orders of magnitude lower than that of REEs ores. Thus, extraction of REEs from these materials is challenging. Here we report REEs extraction with environmentally friendly method that successfully concentrated REEs from312 ppm in fly ash to 99.4% in the final product. Especially, the five critically important REEs（Dy, Eu, Nd.Tb. and Y） account for up to ～63% of the total weight of all REEs in the final 99.4%-purity product. Coal fly ash is one of the major solid coal utilization byproducts, representing great potential resources for REEs extraction. Extraction of REEs from these unconventional resources could be the way to secure domestic supply of these critical materials.
基金Under the auspices of National Key Technology Research and Development Program(No.2012BAB03B01)National Natural Science Foundation of China(No.41273015,51278172,51478167)
文摘The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments.
基金Supported by the National Natural Science Foundation of China(21476121,21322604)NSAF(U1530107)+1 种基金the Natural Science Foundation of Beijing(2162020)Tsinghua University Initiative Scientific Research Program(2014z21026)
文摘Solvent extraction kinetics of Sm（Ⅲ）, Eu（Ⅲ） and Gd（Ⅲ） from hydrochloric acid have been focused on using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester （P507） with Anordning for Kontinuerlig Undersokning av Fordelningsfaktore rid Vatske Extraction （AKUFVE）. Compared with the conventional set-up, some advantages emerge obviously, for example, fast phase separation, easy operation and convenience of kinetic data acquisition. First of all, the extraction mechanism was discussed based on the dimeric model of P507. Secondly, the effects of stirring speed were investigated and 420 r-min-1 was determined of the following experiments. The effects of pH, concentration of rare earth elements （REEs） and P507 on the extraction rate were analyzed. The results indicated that the extraction mechanism changed with the increasing concentration of P507. Then, the experiments with different temperature were carried out. It turned out that the values of apparent activation energy （Ea） for Sm（Ⅲ）, Eu（Ⅲ） and Gd（Ⅲ） extracted by P507 were 26.80 kJ-mol-1, 13.40 kJ.mol-1 and 1.10 kJ- mol- 1 respectively, the resistance of the entire process was limited by diffusion or both of diffusion and reaction. Finally, the correlation equations were obtained, and the theoretical results fit with the experimental data well, most relative error was within ± 30%.
基金Supported by the National Natural Science Foundation of China(No.41376050)
文摘A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3–785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations(∑REE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow(SHF), normal flow(NF), low flow(LF) and high flow(HF) season, respectively. The R_(( L/M)) and R_((H/M)) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEsenrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fl uctuate and positively correlate to salinity in estuary, probably because of the geochemical behavior differences between Y and Ho.
基金Project(40839910) supported by the National Natural Science Foundation of China
文摘The material sources and control factors of rare earth elemems （REEs） for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying （borehole number： ZK10-6）, Sichuan Province, South China, were investigated. All samples were determined by inductively coupled plasma mass spectrometry （ICP-MS）. The chondrite-normalized distribution patterns of mudstone samples are uniform. All samples belong to the light rare earth element （LREE）-rich type and are enriched in LREEs relative to heavy rare earth elements （HREEs）. The distribution curves of REEs in mudstone are highly similar to Mount Emei basalt and the three periods of REEs enrichment correspond to three Mount Emei basalt eruption cycles in Longtan period. The results indicate that REE patterns are not controlled by materials from the seawater or land plants. The predominant sources of REEs are from terrigenous material as indicated by negative Eu anomaly. So, the sources of REEs are controlled by terrigenous material, and the Mount Emei basalt is the predominant source of terrigenous material. Thus, transgression-regression is another control factor of REEs enrichment.
