Arsenate sorption on monohydrocalcite by coprecipitation during transformation to aragonite
| Autor: | Takashi Munemoto, Keisuke Fukushi, Minoru Sakai, Yoshio Takahashi, Yuka Yokoyama |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Calcite
Environmental Engineering Coprecipitation Health Toxicology and Mutagenesis Aragonite Arsenate Analytical chemistry Mineralogy chemical and pharmacologic phenomena Sorption 010501 environmental sciences engineering.material 010502 geochemistry & geophysics complex mixtures 01 natural sciences Pollution Monohydrocalcite Partition coefficient chemistry.chemical_compound Adsorption chemistry engineering Environmental Chemistry Waste Management and Disposal 0105 earth and related environmental sciences |
| Zdroj: | Journal of Hazardous Materials. 304:110-117 |
| ISSN: | 0304-3894 |
| Popis: | The metastability of monohydrocalcite (CaCO3·H2O: MHC) suggests high reactivity to dissolved trace elements. Using kinetic and isotherm sorption experiments with different reaction times (24h, 48h), As(V) sorption on MHC was examined to elucidate As(V) uptake by MHC. Although the MHC was transformed to aragonite with time, the MHC in higher As(V) loading conditions was able to persist longer than in lower loading conditions. Actually, As(V) uptake was negligible for samples in which the MHC remained. However, remarkable uptake of As(V) was observed for samples in which a complete transformation of MHC to aragonite occurred. Results of kinetic study confirmed that the timing of the MHC transformation coincided perfectly with that of As(V) removal from the solution. XAFS measurements showed that the local structure of As after the MHC transformation was almost identical to that of As in the As(V) coprecipitated aragonite. Sorption behavior of As(V) during the transformation is explainable theoretically by the substitution of As(V) into the aragonite structure. The distribution coefficient and (apparent) maximum sorption capacity of As(V) sorption on MHC after 48h at low-to-moderate As(V) concentrations are 500L/kg and 25μmol/g, respectively, which are much higher than those of simple adsorption of As(V) on calcite. |
| Databáze: | OpenAIRE |
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