Surface complexation of U(VI) on goethite (α-FeOOH)

Sorption of U(VI) to goethite is a fundamental control on the mobility of uranium in soil and groundwater. Here, we investigated the sorption of U on goethite using EXAFS spectroscopy, batch sorption experiments and DFT calculations of the energetics and structures of possible surface complexes. Based on EXAFS spectra, it has previously been proposed that U(VI), as the uranyl cation , sorbs to Fe oxide hydroxide phases by forming a bidentate edge-sharing (E2) surface complex, >Fe(OH)₂UO₂(H₂O)_n. Here, we argue that this complex alone cannot account for the sorption capacity of goethite (α-FeOOH). Moreover, we show that all of the EXAFS signal attributed to the E2 complex can be accounted for by multiple scattering. We propose that the dominant surface complex in CO₂-free systems is a bidentate corner-sharing (C2) complex, (>FeOH)₂UO₂(H₂O)₃ which can form on the dominant {101} surface. However, in the presence of CO₂, we find an enhancement of UO₂ sorption at low pH and attribute this to a (>FeO)CO₂UO₂ ternary complex. With increasing pH, U(VI) desorbs by the formation of aqueous carbonate and hydroxyl complexes. However, this desorption is preceded by the formation of a second ternary surface complex (>FeOH)₂UO₂CO₃. The three proposed surface complexes, (>FeOH)₂UO₂(H₂O)₃, >FeOCO₂UO₂, and (>FeOH)₂UO₂CO₃ are consistent with EXAFS spectra. Using these complexes, we developed a surface complexation model for U on goethite with a 1-pK model for surface protonation, an extended Stern model for surface electrostatics and inclusion of all known UO₂-OH-CO₃ aqueous complexes in the current thermodynamic database. The model gives an excellent fit to our sorption experiments done in both ambient and reduced CO₂ environments at surface loadings of 0.02-2.0 wt% U.     

Chinese Journal of GEOCHEMISTRY(ISSN 1000-9426)CONTENTS(2007)

No. 1 Hydrocarbon migration characteristics of the Lower Cretaceous in the Erlian Basin ZHAO Wenzhi and FANG Jie (1) Rare metal-bearing pegmatites from the Southeastern Desert of Egypt: Geology, geochemical characteristics, and petrogenesis Gehad M. Saleh…     

Provenance of Upper Devonian clastic (meta)sediments of the Böllstein Odenwald (Mid-German-Crystalline-Zone,Variscides)

International Journal of Earth Sciences - Detrital zircons separated from paragneisses of the northern Böllstein Odenwald (Mid-German Crystalline Zone, Variscides) yielded Cambrian to Upper...     

Presentation of the French Society of Mineralogy and Crystallography(SFMC)

The French Society of Mineralogy and Crystallography is honoured to be invited to give a short presentation of its activity to the Chinese Society for Mineralogy,Petrology and Geochemistry.BRIEF HISTORY AND SOME FRENCH FOUNDERS OF MINERALOGY     

Bay of Bengal Monsoon Experiment (BOBMEX) — A component of the Indian Climate Research Programme (ICRP)

The Indian Climate Research Programme (ICRP) focuses on the study of climate variability and its impact on agriculture. To address the role of the Bay of Bengal in monsoon variability, a process study was organised during July–August 1999, deploying research ships, buoys, INSAT, coastal radar and conventional observational systems to collect information about the coupled ocean-atmosphere system over the warm waters of the Bay of Bengal. The paper gives the background of the ICRP and the organisation and implementation of the Bay of Bengal Monsoon Experiment (BOBMEX) in its field phase.     

Structural properties of α-berlinite (AlPO4)

We present first principles calculations for the structural properties of α-berlinite (AlPO₄) as a function of pressure. The calculations were performed within the local density approximation using ab initio pseudopotentials and a plane-wave basis. We determined the lattice parameters, cohesive energy, and bulk modulus by minimizing the enthalpy of the solid with respect to lattice parameters. We find good agreement, within ∼2–3% of the experimentally observed values, for the structural properties as a function of pressure. Received: 3 January 1997 / Revised, accepted: 16 April 1997     

List of Publications for Journal of China University of Geosciences (English Version) in 2001

No. 1Fischer plots of Wumishan cyclothems, Precambrian records of third-order sea-level changes………………………………………… 001Mei Mingxiang , Ma Yongsheng , Zhou Hongrui , Du Benming , Luo Zhiqing and Guo Qingyin Study on sequence stratigraphy of Zhujiang and Zhuhai formations, Zhu III subbasin, Pearl River Mouth basin, South China Sea………………………………………………………… 011Nie Fengjun, Li Sitian , Wang Hua, Xie Xinong . Wu Keqiang and Jiang Meizhu Griesbachian cycl…     

Change in carbon flux (1960–2015) of the Red River (Vietnam)

Global riverine carbon concentrations and fluxes have been impacted by climate and human-induced changes for many decades. This paper aims to reconstruct the longterm carbon concentrations and carbon fluxes of the Red River, a system under the coupled pressures of environmental change and human activity. Based on (1) the relationships between particulate and dissolved organic carbon (POC, DOC) or dissolved inorganic carbon (DIC), and suspended sediments (TSS) or river water discharge and on (2) the available detailed historical records of river discharge and TSS concentration, the variations of the Red River carbon concentration and flux were estimated for the period 1960–2015. The results show that total carbon flux of the Red River averaged 2555?±?639 kton C year^?1. DIC fluxes dominated total carbon fluxes, representing 64% of total, reflecting a strong weathering process from carbonate rocks in the upstream basin. Total carbon fluxes significantly decreased from 2816 kton C year^?1 during the 1960s to 1372 kton C year^?1 during the 2010s and showed clear seasonal and spatial variations. Organic carbon flux decreased in both quantity and proportion of the total carbon flux from 40.9% in 1960s to 14.9% in 2010s, reflecting the important impact of dam impoundment. DIC flux was also reduced over this period potentially as a consequence of carbonate precipitation in the irrigated, agricultural land and the reduction of the Red River water discharge toward the sea. These decreases in TSS and carbon fluxes are probably partially responsible for different negatives impacts observed in the coastal zone.     

Development of a facility for analysis of natural ~(32)Si

The use of peat and sediment cores to reconstruct historical trends in levels of environmental contamination, or to provide palaeoclimatic information, depends critically on the development of accurate chronologies. Radionuclides have been exploited in th…     

List of Publication for Journal of China University of Geosciences(English Version) in 2003

No .1FromFlyschtoMolasse—SedimentaryandTectonicEvolutionofLateCaledonian EarlyHercynianForelandBasininNorthQilianMountains 0 0 1………………………………………………………………………………………………………………DuYuansheng ,WangJiasheng ,HanXinandShiGRCharacteristicsofBacilluscereusSporeCountsinSoilswithUnderlyingGoldMineralizationinNorthwesternSichuan ,China :ResultsfromaPilotStudy 0 0 8……………………………………………………………………………………………………WangHongmei,Ya…     

Experimental and theoretical study of the vibrational properties of diaspore (α-AlOOH)

Vibrational properties of diaspore, α-AlOOH, have been re-investigated using room-temperature single-crystal Raman spectroscopy and low-temperature powder infrared (IR) transmission spectroscopy. First-principles harmonic calculations based on density functional theory provide a convincing assignment of the major Raman peaks and infrared absorption bands. The large width of the Raman band related to OH stretching modes is ascribed to mode–mode anharmonic coupling due to medium-strength H-bonding. Additional broadening in the powder IR spectrum arises from depolarization effects in powder particles. The temperature dependence of the IR spectrum provides a further insight into the anharmonic properties of diaspore. Based on their frequency and temperature behavior, narrow absorption features at ~2,000 cm⁻¹ and anti-resonance at ~2,966 cm⁻¹ in the IR spectrum are interpreted as overtones of fundamental bending bands.     

Radiolarian-Based zonal scheme of the cretaceous (Albian–Santonain) of the Tethyan regions of Eurasia

A scheme of radiolarian zonal subdivision is proposed for the upper Albian–Santonian of the Tethyan regions of Eurasia. The upper Albian contains one zone: Crolanium triangulare; the Cenomanian contains three zones: Patellula spica (lower Cenomanian), Pseudoaulophacus lenticulatus (middle Cenomanian), and Triactoma parva (upper Cenomanian); the Turonian contains four zones: Acanthocircus tympanum (lower Turonian (with no upper part)), Patellula selbukhraensis (upper part of the lower Turonian), Phaseliforma turovi (middle Turonian (with no upper part)), and Actinomma (?) belbekense (upper part of the middle Turonian–upper Turonian); the Coniacian contains two zones: Alievium praegallowayi (lower part of the Coniacian) and Cyprodictyomitra longa (upper part of the Coniacian); the Santonian contains three zones: Theocampe urna (lower Santonian), Crucella robusta (middle Santonian–lower part of the upper(?) Santonian), and Afens perapediensis (upper part of the upper Santonian). The biostratigraphic subdivisions are correlated with biostrata in the schemes proposed previously for the Tethys and Pacific. A new species Patellula selbukhraensis Bragina sp. nov. is described.     

Subsidence and uplift of Sidoarjo (East Java) due to the eruption of the Lusi mud volcano (2006–present)

Global positioning system (GPS) and satellite-based InSAR (Interferometric Synthetic Aperture Radar) measurements of the subsidence and uplift of a populated area of Sidoarjo, East Java are due to the eruption of the Lusi mud volcano (2006–present). These data are the first direct quantitative measurements of deformation due to the growth of a mud volcano edifice. The GPS data were recorded over periods of a few hours to several months and show that between June 2006 and September 2007, the earth’s surface has been subsiding at rates of 0.1–4 cm/day. Maximum rates of subsidence occurred in an area 300–400 m to the northwest of the main mud volcano vent. Horizontal displacements were 0.03–0.9 cm/day and were also towards this area. In general uplifts of up to 0.09 cm/day were recorded in areas outside of the edifice. Changes in elevation measured using satellite imagery (InSAR technique) provide regional datasets of subsidence and uplift. They confirm that during the first year a roughly circular area was undergoing sag-like subsidence centered to the northwest of the main vent and that uplift was occurring 3–4 months after the initiation of the eruption due to the movement Watukosek fault system. Subsidence occurred due to the weight of mud and man-made dams and the collapse of the overburden due to removal of mud from the subsurface. Assuming constant rates of subsidence of 4 cm/day, then in the centre of the edifice there would be up to 44 m of subsidence in 3 years, and up to 16 m in 10 years. The mud volcano is now in a self-organizing state with new fluid conduits forming as a result of the collapse. An erratum to this article can be found at     

Amino-acid composition of algal (“stromatolitic”) limestones (Gannat,Massif-Central,France)

The amino-acid compositions of limestones whose origin is thought to be related to the activity of Cyanophyceae have been studied to determine whether the characteristic components of these organisms would be present as geochemical fossils. A significant amount of amino acids is present and the content can be divided between a “free amino-acid fraction” and a “combined amino-acid fraction” containing different amounts of acidic and basic amino acids. There is evidence to suggest that the amino acids and amino sugars isolated are indeed contemporaneous with the formation of the sediments. The absence of diaminopimelic acid and the very small amount of muramic acid present shows that these two important components of algal and bacterial cell-membranes have apparently been extensively degraded.     

Abstracts of EarthScience—Journal of China University of Geosciences(Chinese Version ,Volume 27,2002 )

Ｎｏ .1ＥａｒｌｙＰｅｒｍｉａｎＲａｄｉｏｌａｒｉａｎｓｆｒｏｍＢａｂｕＯｐｈｉｏｌｉｔｉｃＭ啨ｌａｎｇｅｉｎＳｏｕｔｈｅａｓｔｅｒｎＹｕｎｎａｎ .ＦｅｎｇＱｉｎｇｌａｉ,ＬｉｕＢｅｎｐｅｉ.2 7(1) :1- 3.ＴｈｅＥａｒｌｙＰｅｒｍｉａｎｒａｄｉｏｌａｒｉａｎｓｗｅｒｅｆｏｕｎｄｆｒｏｍｔｈｅｃｈｅｒｔｏｆｔｈｅＢａｂｕｏｐｈｉｏｌｉｔｉｃｍ啨ｌａｎｇｅｉｎｓｏｕｔｈｅａｓｔｅｒｎＹｕｎｎａｎ .ＴｈｉｓｒａｄｉｏｌａｒｉａｎａｓｓｅｍｂｌａｇｅｉｎｃｌｕｄｅｓＰｓｅｕ ｄｏａｌｂａｉｌｌｅｌｌａｓｃａ…     

Content of Acta Geologica Sinica (Trial English Edition)

Vol.60 NO.,19863Planktonie Formaminfera in the Continental SloPe ofthe Northern Sout幻China Sea during theL邹t 130,000 Years and thei:Paleo一oeeanograPhic IrnPlieatlons· ·················一叭叨尸玩“。(汪品先),MoQ翻反列卜,(阂秋宝)J万。双h、腼(卞云华)a ndFe时w”加(冯文科)The Earliest Ordovieian Graptolite Sequenee of Hunjjang,Jilin Prov主nee,China············,,·········,·····,,,········,·… ·’“”‘’·‘二”·’········…     

~(40)Ar/~(39)Ar Dating of Deformation Events and Reconstruction of Exhumation of Ultrahigh-Pressure Metamorphic Rocks in Donghai, East China

Recent investigations reveal that the ultrahigh-pressure metamorphic (UHPM) rocks in the Donghai region of East China underwent ductile and transitional ductile-brittle structural events during their exhumation. The earlier ductile deformation took place under the condition of amphibolite facies and the later transitional ductile-brittle deformation under the condition of greenschist facies. The hanging walls moved southeastward during both of these two events. The 40Ar/39Ar dating of muscovites from muscovite-plagioclase schists in the Haizhou phosphorous mine, which are structurally overlain by UHPM rocks, yields a plateau age of 218.0±2.9 Ma and isochron age of 219.8Ma, indicating that the earlier event of the ampibolite-facies deformation probably took place about 220 Ma ago. The 40Ar/39Ar dating of oriented amphiboles parallel to the movement direction of the hanging wall on a decollement plane yields a plateau age of 213.1±0.3 Ma and isochron age of 213.4±4.1 Ma, probably representing the age o