Sorption and desorption of arsenate and arsenite on calcite

Sø, Helle Ugilt; Postma, Dieke; Jakobsen, Rasmus; Larsen, Flemming

doi:10.1016/j.gca.2008.09.023

Cited by 136 publications

(77 citation statements)

References 38 publications

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“…Alexandratos et al (2007), Sø et al (2008) and Yokoyama et al (2012) claimed that only As(V) can incorporate in calcite. Sø et al (2008) explained such an effect on the basis of the different chemical behavior of arsenate and arsenite oxyanions.…”

Section: Introductionmentioning

confidence: 99%

Arsenic uptake in bacterial calcite

Catelani

Perito

Bellucci

et al. 2018

Geochimica et Cosmochimica Acta

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Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and Xray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03 Å ) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

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Section: Introductionmentioning

confidence: 99%

Arsenic uptake in bacterial calcite

Catelani

Perito

Bellucci

et al. 2018

Geochimica et Cosmochimica Acta

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“…All of these mechanisms are likely to play a role in our experiments, given the presence of kaolinite (11% d.w.) and chlorite (3.9% d.w.), pH of 7.2 and high [Ca] (4 mM). Sorption onto calcite (12% d.w.) at ambient carbon dioxide pressure (pCO 2 = 10 −3.5 atm) would require a higher pH (> 8.3) (Sø et al, 2008). Slow As(V) removal, which is implemented in the model as an irreversible kinetic reaction, most probably represents intra-/inter- Table 3 Forward (k f ), backward (k b ) and irreversible (k i ) rate constants, plus the equilibrium sorption constant (log K) used in the multi-reaction models.…”

Section: Arsenic Abiotic Sequestrationmentioning

confidence: 99%

Speciation dynamics of oxyanion contaminants (As, Sb, Cr) in argillaceous suspensions during oxic-anoxic cycles

Markelova

Couture

Parsons

et al. 2018

Applied Geochemistry

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A B S T R A C TArgillaceous geological formations are considered promising repositories for waste containing inorganic contaminants. However, the sequestration capacity of an argillaceous natural barrier may change as a result of dynamic environmental conditions, in particular changes in redox state. Here, we imposed redox cycles to argillaceous suspensions amended with a mixture of the inorganic contaminants As(V), Sb(V), Cr(VI), by alternating 7-day cycles of sparging with either oxic or anoxic gas mixtures. During the redox cycles, we assessed the relative importance of different contaminant sequestration mechanisms under sterile and non-sterile conditions. The non-sterile experiments were carried out 1) with the argillaceous material as is, that is, containing the native microbial population, 2) with the addition of ethanol as a source of labile organic carbon, and 3) with the addition of both ethanol and a soil microbial inoculum. In order to capture the observed solid-solution partitioning trends, a series of mixed thermodynamic-kinetic models representing the dynamic conditions in the experiments were developed using PHREEQC. Parameter values for processes such as adsorption, which occurred in all experiments, were kept constant across all the simulations. Additional formulations were introduced as needed to account for the microbial detoxification and respiration of the contaminants in the increasing complexity experiments. Abiotic adsorption of As and abiotic reductive precipitation of Cr dominated sequestration of these two contaminants under all experimental conditions, whereas the presence of microorganisms was essential to decrease the aqueous Sb concentration. Once reduced, As(III), Sb(III), and Cr(III) were not reoxidized upon exposure to dissolved O 2 in any of the experiments. Neither the mineralogy nor the native microbiota catalysed contaminant oxidation processes. Thus, kinetically, the reduction of As(V), Sb(V), and Cr(VI) was irreversible over the experimental duration (49 days). The capacity of the argillaceous matrix to reduce and sequester the aqueous contaminants, without subsequent remobilization to the aqueous phase during the oxic periods, supports the use of argillaceous barriers for geologic waste storage.

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“…La caliza contiene aproximadamente 4% de materiales insolubles, de los cuales la octava parte corresponde a hierro (Guerrero, 2001). La calcita ha sido estudiada como adsorbente de arsénico, As (V), y se han demostrado buenos resultados en la remoción de este, los cuales han alcanzado una capacidad de adsorción en su área de 18,73 µg/m2 (Sø, Postma, Jakobsen & Larsen, 2008). Es un tipo de roca muy común en Costa Rica, con reservas abundantes en la Península de Santa Elena, Turrialba y el sur del Valle Central (Denyer & Kussmaul, 2000 (Kumwenda, 2009).…”

Section: Y=28095123unclassified

Selección teórica de adsorbentes potenciales naturales de bajo costo para la remoción de arsénico en el agua de consumo humano en Costa Rica

Acuña-Piedra

Araya-Obando

Romero-Esquivel

2016

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<p class="p1">El arsénico presente en agua puede llegar a causar serios problemas en la salud de los consumidores. En Costa Rica, se han identificado aguas de consumo humano con concentraciones mayores al límite permitido (10 µg/L). La adsorción del arsénico por un material adsorbente ha sido utilizada en otros países con éxito. Para ello, se han utilizado gran variedad de materiales adsorbentes sintéticos, naturales o subproductos de procesos industriales o agrícolas. Los adsorbentes sintéticos, por lo general, presentan alta capacidad de adsorción pero representan altos costos adquisitivos, contrariamente a los materiales naturales y de residuos de procesos que aunque tienen capacidades de adsorción menores, son más baratos y se encuentran más fácilmente. En el marco del contexto en mención, se presenta un análisis de las opciones de materiales naturales de origen local y de bajo costo adquisitivo, con un contenido relativamente alto de óxidos de hierro, aluminio y titanio, que podrían ser utilizados para remover arsénico del agua. Los materiales identificados son biotita, piedra caliza, diatomita, arenas ricas en magnetita y rocas piroclásticas de composición basáltica. Todos esos materiales son originarios de la zona de Guanacaste, afectada por la presencia de arsénico en agua.</p>

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Sorption and desorption of arsenate and arsenite on calcite

Cited by 136 publications

References 38 publications

Arsenic uptake in bacterial calcite

Arsenic uptake in bacterial calcite

Speciation dynamics of oxyanion contaminants (As, Sb, Cr) in argillaceous suspensions during oxic-anoxic cycles

Selección teórica de adsorbentes potenciales naturales de bajo costo para la remoción de arsénico en el agua de consumo humano en Costa Rica

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