Sorption of Trace Elements on Mineral Surfaces: Modern Perspectives from Spectroscopic Studies,and Comments on Sorption in the Marine Environment

The partitioning (or sorption) of trace elements from aqueous solutions onto mineral surfaces and natural organic matter (NOM) has played a major role in determining the trace element content of natural waters. This review examines sorption processes on mineral surfaces for nine trace elements (Cr, Co, Ni, Cu, Zn, Sr, Cd, Hg, Pb), focusing on the results of modern x-ray spectroscopic studies. Such studies provide unique information on the structure and composition of sorption products, including their mode of attachment to mineral surfaces or functional groups in NOM under in situ conditions (i.e., with aqueous solution present at 25°C). The types of chemical reactions (acid-base, ligand exchange, redox, dissolution/reprecipitation) that can occur at mineral-aqueous solution interfaces are also reviewed, and some of the factors that affect the reactivity of mineral surfaces are discussed, including changes in the geometric and electronic structures of mineral surfaces when they first react with aqueous solutions and constraints on the bonding of adions to surface functional groups imposed by Pauling bond valence sums. A summary of electrical double layer (EDL) theory is presented, including the results of several recent x-ray spectroscopic and parameter regression studies of the EDL for metal-(oxyhydr) oxide-aqueous solution interfaces. The effects of common inorganic and organic complexants on the sorption of trace metal cations at mineral-solution interfaces are considered, in the context of spectroscopic studies where possible. The results of sorption studies of trace metal cations on NOM, common bacteria, and marine biomass are reviewed, and the effects of coatings of NOM and microbial biofilms on cation uptake on mineral surfaces are discussed, based on macroscopic and spectroscopic data. The objective here is to assess the relative importance of inorganic versus organic sorption processes in aquatic systems. The paper concludes with a discussion of the effects of water composition on trace element removal mechanisms, with the aim of providing an understanding of the effects of the high salinity of seawater on trace element sorption processes. The information presented in this review indicates that sorption processes on mineral, NOM, and microbial and algal surfaces, including true adsorption and precipitation, are highly effective at removing trace elements from natural waters and generally supports Krauskopf's (1956) conclusion that such processes are likely responsible for the present trace element concentrations in seawater.     

矿物表面活性及其量度

矿物及其材料的表面活性及其表面反应性的具体表征，它是由矿物表面功能基所控制。由于矿物表面金属原子的电负性不同，以及它所处的配位环境不同，常表现出不同的极性、荷电性和Lewis酸碱性，它与溶质和溶剂分子之间反应（成键）能力也不同。在热力学上表现为反应自由能变化也不同。因此，量度矿物表面活性就是量度其表面极性、荷电性和Lewis酸碱性，它既可用化学方法，也可用热力学的方法。前者是通过反应作用量来量度，后者通过反应作用能来量度。然而现代矿物谱学的方法更能给出矿物及其材料表面反应活性的本质和详细信息。     

环境矿物界面反应动力学

环境矿物界面反应动力学主要探讨地表中各种有毒、有害离子或分子与矿物表面之间的反应速率与反应机制。矿物表面存在一组化学活性很强的表面功能基，当它们与环境中毒害物质发生作用时，会因其极性、荷电性和Lewis酸碱性不同而表现出不同的作用力和反应速率，进而控制有毒、有害物质在大气、水体和沉积物中的赋存形态，稳定性及迁移转化速率。本文简要介绍了环境矿物界面反应动力学理论，并给出几个应用实例。     

矿物表面基团与表面作用

矿物的表面或界面过程存在于一切地质过程中,并在材料和环境科学领域得到广泛应用。矿物的表面结构、表面基团与表面作用之间存在着一定的内在联系,矿物结构的多样性决定了表面基团类型的多种性和表面作用的多样性。本文较系统地介绍了矿物表面功能基、表面配位反应、表面配合反应、表面氧化还原反应、表面异位催化反应和表面离子交换反应的类型及作用机制。     

矿物界面作用与环境工程材料

矿物水界面作用是环境地球化学研究的基础,它控制着世界淡水质量、土壤发生与发展、表生地质作用中元素迁移与富集等过程,是矿物环境工程材料的理论基础［１］。这是因为矿物水界面作用发生于矿物表面,许多环境工程材料是通过材料表面吸附（或共沉淀）作用去清除水...     

Desert varnish—nature's smallest sedimentary formation

Desert varnish is a surface stain, coating bedrock surfaces as well as surface sediments in arid regions around the world. The desert varnish itself comprises a sedimentary formation containing internal microscopic laminations. The chemical and mineral composition of each layer reflects the climate conditions under which it was deposited. A detailed study of these individual layers is used to both reconstruct local and regional climate history as well as quantitatively date geomorphic surfaces. Although the mineral and chemical components comprising desert varnish consist of wind‐blown dust, atmospheric aerosols and microbes, the role of microbial activity in the formation of desert varnish remains a source of active research and lively debate.     

Surface analysis of particles in mine tailings by time-of-flight laser-ionization mass spectrometry (TOF-LIMS)

  Time-of-flight laser-ionization mass spectrometry was applied to study the chemical composition of mineral particle surfaces in a sulphide-rich mine-tailings impoundment. This surface-sensitive technique provides chemical information from surfaces of irregularly shaped mineral particles (both conductive and insulators) less than 100 μm in diameter, which are considered to be representative of particle surface coatings in the tailings pile (after drying). In addition, depth profiles in the mineral particles were obtained. The combination of speed of analysis (1 min), small beam-diameter (2–4 μm), surface sensitivity (2–10 nm), trace-element sensitivity, and capability to analyze rough surfaces makes this method useful as a complement to studies of pore-water geochemistry and tailings mineralogy. As an example, the behavior of Pb and As in the Kidd Creek tailings dam near Timmins, Ontario, Canada, was studied, using a combination of surface analyses, and pore-water geochemical data. Received: 22 February 1995 / Accepted: 6 January 1996     

Effect of sulfide impurities on the reactivity of pyrite and pyritic concentrates: a multi-tool approach

Sulfide mineral oxidation, primarily pyrite and pyrrhotite, generates acid mine drainage during weathering. Successful management of acid generating wastes entails the suppression of the initiation of oxidation reactions. The reactivity of pyrite depends on ore mineralogy, including the effects of associated sulfide impurities. The electrochemical surface characterization study using cyclic voltammetry with carbon paste electrodes containing minerals particles (CPE-Mineral) is an effective tool for demonstrating how the various mineral characteristics work together to influence the overall reactivity of the mineral. This study was supported by chemical, mineralogical and leachate chemistry data. The results show that the presence of other sulfides in contact with pyrite at the beginning of the weathering process is the most important parameter affecting pyrite reactivity, which is likely to be oxidized and passivated. In more advanced stages of leaching, mineral coatings which passivate the pyrite surfaces tend to play the most important role in defining the reactivity of pyrite. The electrochemical response of pyritic samples in conjunction with the evolution of the chemical quality of the leach solution in the simple experimental device here used, could then provide valuable information on acid mine drainage generation.     

从矿物粉晶表面反应性到矿物晶面反应性——以黄铁矿氧化行为的晶面差异性为例

地球系统中各种矿物相的物理化学反应大多是从矿物表面或界面开始的。要揭示矿物表面反应性的本质,就需要从控制其反应性的表面结构入手。由于实验条件的限制,绝大多数关于矿物表面物理化学性质的研究主要采用粉晶作为研究对象。尽管粉晶方法在研究诸如硅酸盐、碳酸盐溶解和沉淀结晶等过程中被普遍采用,但这种基于矿物粉晶的研究方法还是有一定的不足。因为形成粉晶的破碎研磨过程会导致晶体高能面的出现,高能面所具有的高活性可能会加速其反应过程,应用于地球化学反应的计算结果就可能高估了实际的地球化学反应速率。本研究以黄铁矿表面氧化反应的晶面差异性为例,从晶面结构制约反应性的角度出发,重新审视了黄铁矿氧化的相关问题,弥补了传统"粉晶研究"中对黄铁矿氧化速率和氧化机理认识的缺陷。黄铁矿宽范围的氧化速率实测值很可能是由不同晶面间较大的反应性差异导致;水在黄铁矿的氧化过程中同时扮演着传递电子的催化剂和反应物的角色,也是黄铁矿氧化反应速控步(rate-limiting step)的核心物质。这些认识首次明确了黄铁矿不同晶面反应性差异的重要性,并提示我们应将传统表面矿物学的研究推向更为精确的晶面矿物学水平。这一从晶面角度考察发生在矿物表面的地球化学反应的研究方法可为构建更为精确的地球化学模型提供理论基础。     

Mineral systems,their types,and distribution in nature. I. Khibiny,Lovozero, and the Mont Saint-Hilaire

In accordance with the set of species-defining chemical elements in minerals, n-component systems (where n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) for all mineral species (4952) known to 2014 inclusive were distinguished. Seventy chemical elements have been established to be species-defining, which are distributed by mineral systems as follows: 1 (29), 2 (62), 3 (68), 4 (61), 5 (61), 6 (55), 7 (49), 8 (38), 9 (28), and 10 (19). The number of mineral species in which certain chemical elements are species-defining has been specified. Oxygen (4041), hydrogen (2755), silicon (1448), calcium (1139), sulfur (1025), aluminum (960), iron (917), sodium (914), copper (616), phosphorous (580), arsenic (575), and magnesium (550) are the leading elements in minerals in the Earth’s crust. It has been found that the most species-defining elements are normally distributed by mineral systems. The distributions of mineral species in various systems from the Khibiny and Lovozero, Kola Peninsula, Russia; and Mont Saint-Hilaire, Quebec, Canada peralkaline plutons were compared and the characters of species-defining element distribution in these localities were compared. Si, Na, K, C, F, Ti, Ce, Zr, Nb, Sr, and Th are “excess” species-defining elements in minerals from the plutons compared to the total number of mineral species, whereas S, Cu, Pb, Cl, B, Te, Ag, Ni, and Be are “scarce” elements.     

新疆磁海铁矿床中黑柱石的发现及其地质意义

黑柱石是一种不常见的夕卡岩标型矿物,本次研究在新疆磁海矿区首次发现黑柱石。本文对磁海矿区的黑柱石产出地质环境、矿物共生组合、化学成分、光学性质等进行了研究。化学成分均由电子探针分析求得,计算化学简式为Ca0.98(Fe1.72Mn0.07Mg0.11)1.902+(Fe0.95Al0.03)0.983+[Si2.00O7]O(OH)。磁海矿区黑柱石的形成与基性次火山热液活动有关,是一种特殊的退变质(蚀变)夕卡岩矿物;在成矿作用晚期,随着热液活动加强,早期夕卡岩矿物可退变质形成黑柱石。黑柱石形成时间较晚,对早期形成的磁铁矿起贫化作用。将磁海矿区黑柱石与国内外其它矿区黑柱石的化学成分进行了对比,认为磁海矿区黑柱石为普通黑柱石。黑柱石在常用的矿物中较少提及,应该引起重视。     

Point of zero charge of weathered forsterite

The point of zero charge of forsterite shifts from an estimated 8.9 for the unaltered mineral to 8.4 and 8.0, respectively, after being weathered artificially for 1 h and 4 h. These results corroborate the presence of magnesium-deficient surfaces on the weathered minerals, also indicated by chemical analyses of the solutions. H⁺ and OH^? are shown to be potential-determining ions in this system     

吉林省农安县花园陶粒页岩矿床地质特征及成因探讨

本文详细介绍了农安县花园陶粒页岩矿床区域地质概况、矿床的地质特征,矿石的矿物组成、化学成分及矿石特征等。通过分析陶粒页岩的形成条件、矿石结构、矿物化学组成特点并结合区域白垩纪沉积环境特征对矿床成因作了初步探讨。     

Biogeochemical behavior of Ampelozizyphus amazonicus Ducke in the Pitinga mining district, Amazon, Brazil

The vegetal species Ampelozizyphus amazonicus Ducke (Rhamnaceae Family) was chosen as a sampling medium for the lateritic surfaces of the Pitinga Mine in the Amazon region, in order to study the biogeochemical behavior of this species and compare it with the chemical composition of a reference plant. The Pitinga mining district is one of the largest producers of tin in the world. This district contains unique deposits of cryolite and rare metals such as Zr, Nb, Ta, Y and REEs related to granitic bodies that intrude into the volcanic and acid pyroclastic rocks. The results showed that the species A. amazonicus predominantly concentrates significant levels of Zr, Nb, Ta, Th, Be, Sc over U, Hf, Ga and In. These elements are characteristic of the mineral paragenesis for the region, suggesting that this plant can provide a representative sampling medium future geochemical exploration programs in the region.     

A geochemical investigation of pressure solution and the formation of veins in a deformed greywacke

Pressure solution and vein formation often occur simultaneously in shear zones during the deformation of sedimentary rocks. The mineralogical and chemical variations around a typical example of an en echelon zone of quartz veins from north Cornwall are discussed in detail. Solution of quartz is confined to the shear zone and occurs along discrete surfaces. Accumulation of insoluble minerals along these surfaces gives rise to spaced pressure solution cleavage. Petrographic data show that during pressure solution the breakdown of felspar and epidote results in the crystallisation of clay mineral, quartz and siderite. Redistribution of silica within the shear zone by pressure solution does not account for all the quartz in the veins, or for the observed increased concentration of iron and calcium. It is concluded that material was introduced from an external source into the shear zone.     

四川虎牙雪宝顶W-Sn-Be矿床矿物学标型特征及流体对矿物形态的影响

四川虎牙乡雪宝顶钨锡铍矿床产出宝石级绿柱石、白钨矿、锡石、电气石等矿物且晶形完好.共生矿物有长石、方铅矿、石英、方解石、云母等.绿柱石、白钨矿和锡石色彩绚丽, 其成分较为复杂, 类质同象现象普遍, 晶体形貌具有标型意义.对该区代表性矿物绿柱石、白钨矿、锡石等进行了成分研究、形貌描述及矿物共生组合特点分析, 从矿物标型特征、围岩蚀变类型确定了矿床属于高温热液云英岩脉型矿床, 在此基础上重点探讨了板状绿柱石成因.      

邯郸万年矿饮用天然矿泉水的水文地球化学模式

本文根据水－岩相互作用过程中化学热力学理论与方法，研究万年矿含锶矿泉水形成的水文地球化学机理及其主要影响因素。在此基础上，初步提出了万年矿含锶矿泉水形成的水文地球化学模式。     

Essai de synthèse sur les modes d'adsorption ionique en flottation

Résumé L'adsorption des ions sur les surfaces minérales est un phénomène auquel on a recours en flottation pour modifier les propriétés des surfaces. Un cristal naturel présente des faces brillantes et des faces rugueuses. Sur ces deux types de face peuvent se développer des édifices épitactiques. Sur les faces rugueuses on assiste plus spécialement au garnissage de trous ou au remplacement d'ions du cristal, ces processus étant avant tout liés au diamètre ionique. Enfin, certains ions ont simplement une action chimique sur les surfaces minérales ou sur le collecteur.

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Ionic adsorption on mineral surfaces is a phenomenon used in flotation practice for modifying surface properties. Actual crystals show bright or rough faces. On both types of faces, epitactic formations can develop. On rough surfaces it is more probable to obtain a filling of the holes or a replacement of crystal ions. This action is connected closely with ionic radii. However the action of some ions can be a chemical one either on mineral surfaces or on the collector.

     

敦化秋梨沟稀有矿泉水特征与开发利用战略

本文介绍了敦化稀有矿泉水出露的地质环境条件,矿泉水的赋存条件和形成机理,分析了矿泉水的动态特征与稀有化学元素的特征指标,对敦化秋梨沟稀有矿泉水水源地合理开发利用、保护及开发利用战略提出合理化建议。     

Detailed geochemical studies of the initial stages of weathering of alkaline rocks: Ilha de São Sebastião, Brazil

Detailed mineral and chemical studies of samples of syenite rocks with thick weathering rinds, found in the alkaline massifs on Ilha de São Sebastião, illustrate the complex interplay between variables controlling initial weathering processes. An array of geochemical information was obtained by optical and electron microscopy, X-ray analyses, mass spectroscopy and optical spectrometry. Sericite and metahalloysite are the principal phases nucleating and forming as the perthitic feldspar rock matrix disintegrates. Incipient feldspar dissolution and the formation of submicrometer X-ray opaque secondary phases were observed in “fresh rock” material using transmission electron microscopy. Pore waters, from which secondary phases nucleate and grow are under the constant influence, as alteration proceeds, of physical (e.g., accessibility of mineral surfaces to percolating fluids) and chemical (e.g. chemistry of minerals providing the dominant solutes) controls. Minor- and trace-element signatures do not vary significantly except for Zn, Rb, Sr, Y, REE and Pb. Lathanide mobilities appear related to their host-mineral stabilities with respect to ambient pore waters.