| 1. |
- Chen, Hong, et al.
(författare)
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PKU-3 : An HCI-Inclusive Aluminoborate for Strecker Reaction Solved by Combining RED and PXRD
- 2015
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 137:22, s. 7047-7050
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Tidskriftsartikel (refereegranskat)abstract
- A novel microporous aluminoborate, denoted as PKU-3, was prepared by the boric acid flux method. The structure of PKU-3 was determined by combining the rotation electron diffraction and synchrotron powder X-ray diffraction data with well resolved ordered Cl- ions in the channel. Composition and crystal structure analysis showed that there are both proton and chlorine ions in the channels. Part of these protons and chlorine ions can be washed away by basic solutions to activate the open pores. The washed PKU-3 can be used as an efficient catalyst in the Strecker reaction with yields higher than 90%.
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| 2. |
- Meng, Qingpeng, et al.
(författare)
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Geochemical speciation and risk assessment of metals in the river sediments from Dan River Drainage, China
- 2016
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Ingår i: Chemistry in ecology. - : Informa UK Limited. - 0275-7540 .- 1029-0370. ; 32:3, s. 221-237
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the partitioning of metals in surface sediments from the Dan River drainage basin, the source of drinking water for the South to North Water Transfer Project, China, to determine their bioavailability and associated levels of risk. Sediment samples were collected from 99 sites along the Dan River, and the concentration of each element fraction was determined using sequential extraction and inductively coupled plasma-mass spectrometry. The residual fraction was the major phase for most metals sampled. Among the non-residual fractions, greater proportions of Zn, Mn and Cd were transported in in the available phase, whereas Ba, Sb, Pb and As were mainly found in the reducible phase. The oxidisable phase was important for the transport of Ni, Co, Cr and Cu in sediments. This analysis of sediments from the Dan River basin indicates a very high risk of pollution from Cd, Co, Mn, Sb and Zn. Combined with the sediments with extremely high concentrations, the Dan, Laoguan and Yinhua rivers, which have been affected by ore-mining activities, pose a very high risk to the surrounding areas and should be the subject of future studies.
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| 3. |
- Meng, Qingpeng, et al.
(författare)
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Geochemistry of dissolved trace elements and heavy metals in the Dan River Drainage (China) : distribution, sources, and water quality assessment
- 2016
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 23:8, s. 8091-8103
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Tidskriftsartikel (refereegranskat)abstract
- Dissolved trace elements and heavy metals in the Dan River drainage basin, which is the drinking water source area of South-to-North Water Transfer Project (China), affect large numbers of people and should therefore be carefully monitored. To investigate the distribution, sources, and quality of river water, this study integrating catchment geology and multivariate statistical techniques was carried out in the Dan River drainage from 99 river water samples collected in 2013. The distribution of trace metal concentrations in the Dan River drainage was similar to that in the Danjiangkou Reservoir, indicating that the reservoir was significantly affected by the Dan River drainage. Moreover, our results suggested that As, Sb, Cd, Mn, and Ni were the major pollutants. We revealed extremely high concentrations of As and Sb in the Laoguan River, Cd in the Qingyou River, Mn, Ni, and Cd in the Yinhua River, As and Sb in the Laojun River, and Sb in the Dan River. According to the water quality index, water in the Dan River drainage was suitable for drinking; however, an exposure risk assessment model suggests that As and Sb in the Laojun and Laoguan rivers could pose a high risk to humans in terms of adverse health and potential non-carcinogenic effects.
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| 4. |
- Meng, Qingpeng, et al.
(författare)
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Heavy mineral analysis to identify sediment provenance in the Dan River drainage, China
- 2016
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Ingår i: geosciences journal. - : Springer Science and Business Media LLC. - 1226-4806 .- 1598-7477. ; 20:4, s. 449-462
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the provenance of sediments carried by modern rivers can provide information on earth surface processes and help us to interpret geological history more clearly. The types and distribution patterns of surface sediments deposited in river systems are determined mainly by the fluvial flux and weathering of the proximal source rocks. In this paper, analysis of the heavy mineral content of 99 surface sediment samples was used to identify the source of the sediments carried by the Dan River in China. The objectives of this study are to: (1) determine the characteristics and distribution of the sediments, and (2) identify and classify the various depositional areas according to their differing source areas. The Dan River is divided into the lower, middle, and upper reaches to investigate the spatial distribution of heavy minerals. The main minerals detected were amphiboles, pyroxene, epidote, garnet, tourmaline, zircon, apatite, rutile, sphene, anatase, pyrite, and ilmenite. Generally, ilmenite (0.7% to 69.1%), amphibole (0% to 93.6%), epidote (0% to 53.3%), garnet (0% to 36.7%) and pyroxene (0% to 42.0%) were the most frequent detrital heavy minerals in the studied river sections. The Dan River and its tributaries are characterized with respect to their heavy mineral assemblages and heavy mineral indexes. Six depositional areas are distinguished and classified as Depositional area A (the Laoguan, Qi, and Xian rivers), Depositional area B (the Qingyou and Wuguan rivers), Depositional area C (the Laojun River), Depositional area D (the upper reaches of the Dan River), Depositional area E (the Yinhua River), and Depositional area F (the Tao River). The provenance study indicated that the sediments were derived mainly from the proximal exposed rocks. Sediments in the middle reaches of the Dan River were derived from Depositional areas B, C, and E, whereas sediments in the lower reaches were derived mainly from the local rocks along the river. Similar heavy mineral assemblages were obtained from Danjiangkou Reservoir and Depositional area A, especially for the Laoguan River, indicating the significant influence of Depositional area A on the reservoir.
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| 5. |
- Meng, Qingpeng, et al.
(författare)
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Influence of ore deposits on river sediment compositions in Dan River drainage, China
- 2015
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Ingår i: Journal of Geochemical Exploration. - : Elsevier BV. - 0375-6742 .- 1879-1689. ; 159, s. 8-19
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Tidskriftsartikel (refereegranskat)abstract
- We mainly investigated trace element contamination of surface sediments in the Dan River drainage, the source of drinking water for the South to North Water Transfer Project, China, to determine trace element sources and associated levels of risk. Sediment samples were collected at 95 sites along the Dan River in connection with field surveys, and total element concentrations were determined using inductively coupled plasma-mass spectrometry (ICP-MS). Concentrations of most elements were lower than background levels; however, toxic heavy metals, such as As, Cd, Pb, and Sb, showed extremely high concentrations at sites associated with nearby metal ore deposits. Moreover, the spatial variations of contamination by some heavy metals were directly related to the distributions of metal ore deposits in the North and South Qinling terrains; sediment samples with especially high concentrations of Sb and As were from the North Qinling terrain, while sediments with especially high concentrations of Cd and Pb were from the South Qinling terrain, suggesting that metal ore distributions and associated mining activity strongly influence the distribution of heavy metals and heavy metal contamination in the Dan River drainage. Multivariate techniques, including Pearson correlation, hierarchical cluster, and factor analysis, were used to assess the sources of metal contamination. Results indicate that distributions of Al, Ba, Cu, Fe, Mg, Mn, Pb, Sn, Ti, V and Zn are controlled by natural sources; Co and Cr by a combination of geological and anthropogenic inputs; whereas As, Cd, Ni, Sb, and Pb appear to be primarily of anthropogenic origin. The ecological risk associated with heavy metal contamination of sediments was rated as moderate, based on an assessment using geo-accumulation index (I-geo), enrichment factor (EF), potential ecological risk index (RI) and mean probable effect concentration quotient (m(PECQ)).
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| 6. |
- Meng, Qingpeng, et al.
(författare)
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Time constraints on the inversion of the tectonic regime in the northern margin of the North China Craton : Evidence from the Daqingshan granites
- 2014
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Ingår i: Journal of Asian Earth Sciences. - : Elsevier BV. - 1367-9120 .- 1878-5786. ; 79, s. 246-259
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Tidskriftsartikel (refereegranskat)abstract
- The Daqingshan granites are located in a late Mesozoic tectono-magmatic belt at the northern margin of the North China Craton (NCC), and include the Deshengying, Xinisubei, Gulouban, and Kuisu plutons. Ion probe U-Pb zircon dating indicates that the granites were emplaced at 131 +/- 1, 140 +/- 4, 145 +/- 1, and 142 +/- 2 Ma, respectively. All of the granites are alkali- and potassium-rich, with high SiO2 (73.2-76.7 wt.%), K2O (4.50-5.57 wt.%), Na2O (3.60-4.93 wt.%), and K2O/Na2O (0.99-1.49), and low Al2O3 (12.3-14.5 wt.%), CaO (0.45-0.79 wt.%), and MgO (0.12 wt.%). The granites are light rare earth element enriched a La/YbIN = 5.6-48.7). The Xinisubei and Gulouban monzogranites and the Kuisu mylonitic monzogranite have small Eu anomalies (8Eu = 0.65-1.23), low Zr + Nb + Ce + Y (132-321 ppm), and exhibit a negative correlation between P2O5 and SiO2 contents, which are characteristic of highly fractionated I-type granites with a post-collisional origin. The Deshengying monzogranite is distinctive in being an aluminous A-type granite as evidenced by high 10,000 x Ga/AI (>2.6) and Zr + Nb + Ce + Y (312-532 ppm), low Ba and Sr, marked negative Eu anomalies (8Eu = 0.08-0.20), strong Ba, Sr, P, and Ti depletions, and an absence of alkali minerals. This granite was probably produced by partial melting of continental crust heated by hot mantle-derived magmas during crustal extension. The Deshengying monzogranite represents a post-kinematic pluton emplaced into the Daqingshan fold-and-thrust belt, whereas the Kuisu mylonitic monzogranite is a syn-kinematic pluton intruded along the Hohhot detachment fault. It is evident that the Daqingshan area experienced a change from a compressional to an extensional tectonic regime during 145-140 Ma. The post-orogenic collapse may have resulted in extension of the upper continental crust. Subsequently, as the thrust-detachment system became inactive, the lower crust of the NCC underwent modification and melting from 131 Ma. We conclude that the Early Cretaceous tectonic evolution of the Daqingshan area was caused by post-orogenic collapse and melting of the lower crust of the NCC. Delamination of the lower crust in the northern NCC resulted in crustal extension and asthenospheric upwelling, which produced A-type granites. As such, melting of the lower crust in the northwestern part of the NCC took place as early as the late Mesozoic.
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| 7. |
- Meng, Qingpeng, et al.
(författare)
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Zeolite A synthesized from alkaline assisted pre-activated halloysite for efficient heavy metal removal in polluted river water and industrial wastewater
- 2017
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Ingår i: Journal of Environmental Sciences(China). - : Elsevier BV. - 1001-0742 .- 1878-7320. ; 56, s. 254-262
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Tidskriftsartikel (refereegranskat)abstract
- High quality zeolite A was synthesized through a hydrothermal process using alkaline-assisted pre-activated halloysite mineral as the alumina and silica source. The synthesis conditions employed in this study were finely tuned by varying the activating temperature, sodium hydroxide content, water content and Si/Al ratio. The obtained zeolite A showed excellent adsorption properties for both single metal cation solutions and mixed cation solutions when the concentrations of the mixed cations were comparable with those in polluted natural river water and industrial wastewater. High adsorptive capacities for Ag+ (123.05 mg/g) and Pb2+ (227.70 mg/g) were achieved using the synthesized zeolite A. This observation indicates that the zeolite A synthesized from alkaline-assisted pre-activated halloysite can be used as a low-cost and relatively effective adsorbent to purify heavy metal cation polluted natural river water and industrial wastewater.
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| 8. |
- Zhang, Wen, et al.
(författare)
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Age and petrogenesis of late Paleozoic granites from the northernmost Alxa region, northwest China, and implications for the tectonic evolution of the region
- 2017
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Ingår i: International journal of earth sciences. - : Springer Science and Business Media LLC. - 1437-3254 .- 1437-3262. ; 106:1, s. 79-96
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Tidskriftsartikel (refereegranskat)abstract
- The Wudenghan, Huhetaoergai and Zhuxiaobuguhe plutons, northern Alxa region, in the southern Central Asia Orogenic Belt are dated by U-Pb zircon to 383 +/- 3, 356 +/- 3 and 286 +/- 2 Ma, respectively. The late Devonian Wudenghan monzogranite, a highly fractionated I-type granite with epsilon (Nd)(t) (-0.2 to -0.1) and very low (Sr-87/Sr-86) (t) (0.704719-0.706113), is from mantle-derived magmas and shows volcanic arc characteristics. The early Carboniferous Huhetaoergai granodiorite with medium-K calc-alkaline peraluminous characteristics represents a volcanic arc granite generated from partial melting of lower continental crust combined with mantle-derived input. The early Permian Zhuxiaobuguhe pluton, an unfractionated calc-alkaline granodiorite with moderately low epsilon (Nd)(t) (-2.0 to -1.1) and low (Sr-87/Sr-86) (t) (0.708370-0.708462), was likely derived from partial melting of the mafic lower crust of a paleo-volcanic arc and represents a post-collisional granite. Our revised tectonic evolution of the region includes (1) northward subduction of the oceanic crust represented by the Engger Us Ophiolitic Belt and formation of the late Devonian Wudenghan monzogranite, (2) northward subduction of the ocean between the Huhetaoergai and Zhusileng tectonic zones and the formation of the Huhetaoergai volcanic arc granite during the early Carboniferous and (3) the emplacement of the Zhuxiaobuguhe pluton in the early Permian during post-collisional extension.
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| 9. |
- Zhang, Wen, et al.
(författare)
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Age and petrogenesis of Mingshui-Shuangjingzi granites from the northern Beishan area, northwest China, and their implications for tectonic evolution
- 2017
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Ingår i: Geosciences Journal. - : Springer Science and Business Media LLC. - 1226-4806 .- 1598-7477. ; 21:5, s. 667-682
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Tidskriftsartikel (refereegranskat)abstract
- The Mingshui and Shuangjingzi granitic plutons are exposed in the northern Beishan area, in the southern Central Asia Orogenic Belt. U-Pb zircon dating indicates that Mingshui secondary intrusive lithosfacies and Shuangjingzi quartz monzodiorite formed at 328 ± 2 Ma and 272 ± 2 Ma, respectively. The former is composed of grey white monzogranites and potassic altered flesh red monzogranites. Geochemistry indicates they are calc-alkaline I-type granites. Shuangjingzi granites are mainly composed of unfractionated calc-alkaline I-type quartz monzodiorite, granodiorite and monzogranite. The Mingshui grey white monzogranites with negative initial εNd (–2.0 to–1.7) and moderate initial 87Sr/86Sr values (0.706740 to 0.710092) were probably derived from mixing of the depleted mantle (juvenile) component and the Palaeoproterozoic–Archean crust (or sedimentary) component and represent volcanic arc granites. The Shuangjingzi quartz monzodiorites are most likely derived from mafic to intermediate igneous protolith and represent post-collisional granites. This work, combined with the regional geology, suggests the Palaeo-Asian Ocean closed between 328 Ma and 272 Ma in the northern Beishan area.
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| 10. |
- Zhang, Wen, et al.
(författare)
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Discovery of a Neoproterozoic granite in the Northern Alxa region, NW China : its age, petrogenesis, and tectonic significance
- 2016
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Ingår i: Geological Magazine. - 0016-7568 .- 1469-5081. ; 153:3, s. 512-523
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Tidskriftsartikel (refereegranskat)abstract
- A Neoproterozoic granite (Western Huhetaoergai granite) from the Northern Alxa region, southern Central Asia Orogenic Belt (CAOB) is first recognized by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb zircon dating (889±8 Ma). It is a highly fractionated potassium-rich calc-alkaline pluton with low εNd(t) (−2.6 to −1.1) and high (87Sr/86Sr) t (0.727305–0.735626), and is probably derived from a mantle source and assimilated crustal rocks with very high 87Sr/86Sr. Regional geology implies that it may reflect the existence of a microcontinent, and the formation of the Western Huhetaoergai granite is related to the assembly of Rodinia.
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