Occurrence state of co-existing arsenate and nickel ions at the ferrihydrite-water interface: Mechanisms of surface complexation and surface precipitation via ATR-IR spectroscopy.

Title Occurrence state of co-existing arsenate and nickel ions at the ferrihydrite-water interface: Mechanisms of surface complexation and surface precipitation via ATR-IR spectroscopy.
Authors C. Wang; Y. Cui; J. Zhang; M. Gomez; S. Wang; Y. Jia
Journal Chemosphere
DOI 10.1016/j.chemosphere.2018.04.150
Abstract

Arsenic and nickel are common contaminants that usually co-exist in many contaminated natural and mining environments. More research on the interaction of these two contaminants is needed such as their coordination structure and occurrence state at mineral-water interfaces. In this study, we investigated the structure of surface complexes and surface precipitates formed by co-existing As(V) and Ni(II) ions at the ferrihydrite-water interface by varying the order of adsorption processes, pH, aging time and Ni(II) concentration using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). ATR-FTIR analysis revealed the presence of complexed AsONi bonds which produced ternary surface complexes. These ternary AsONi surface complexes formed through a layer by layer alternative coordination on top of the binary AsOFe surface site complexes of ferrihydrite. Such multilayer surface complexes formed as initial surface precipitates which were found to refine their surface structure from amorphous to crystalline phases and were a function of incubation time, coverage of multilayer surface complexes, Ni(II) concentration and pH. Our results presented here can well explain the formation process of surface precipitates on the molecular scale and are of use to forecast the fate and mobility of commonly As(V) and Ni(II) species at the ferrihydrite-water interface commonly found in natural or mine tailings water-soil environments.

Citation C. Wang; Y. Cui; J. Zhang; M. Gomez; S. Wang; Y. Jia.Occurrence state of co-existing arsenate and nickel ions at the ferrihydrite-water interface: Mechanisms of surface complexation and surface precipitation via ATR-IR spectroscopy.. Chemosphere. 2018;206:3342. doi:10.1016/j.chemosphere.2018.04.150

Related Elements

Arsenic

See more Arsenic products. Arsenic (atomic symbol: As, atomic number: 33) is a Block P, Group 15, Period 4 element with an atomic radius of 74.92160. Arsenic Bohr ModelThe number of electrons in each of arsenic's shells is 2, 8, 18, 5 and its electron configuration is [Ar] 3d10 4s2 4p3. The arsenic atom has a radius of 119 pm and a Van der Waals radius of 185 pm. Arsenic was discovered in the early Bronze Age, circa 2500 BC. It was first isolated by Albertus Magnus in 1250 AD. In its elemental form, arsenic is a metallic grey, brittle, crystalline, semimetallic solid. Elemental ArsenicArsenic is found in numerous minerals including arsenolite (As2O3), arsenopyrite (FeAsS), loellingite (FeAs2), orpiment (As2S3), and realgar (As4S4). Arsenic has numerous applications as a semiconductor and other electronic applications as indium arsenide, silicon arsenide and tin arsenide. Arsenic is finding increasing uses as a doping agent in solid-state devices such as transistors.

Nickel

See more Nickel products. Nickel (atomic symbol: Ni, atomic number: 28) is a Block D, Group 4, Period 4 element with an atomic weight of 58.6934. Nickel Bohr ModelThe number of electrons in each of nickel's shells is [2, 8, 16, 2] and its electron configuration is [Ar]3d8 4s2. Nickel was first discovered by Alex Constedt in 1751. The nickel atom has a radius of 124 pm and a Van der Waals radius of 184 pm. In its elemental form, nickel has a lustrous metallic silver appearance. Nickel is a hard and ductile transition metal that is considered corrosion-resistant because of its slow rate of oxidation. Elemental NickelIt is one of four elements that are ferromagnetic and is used in the production of various type of magnets for commercial use. Nickel is sometimes found free in nature but is more commonly found in ores. The bulk of mined nickel comes from laterite and magmatic sulfide ores. The name originates from the German word kupfernickel, which means "false copper" from the illusory copper color of the ore.

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