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Synthesis and thermodynamic properties of arsenate and sulfate-arsenate ettringite structure phases.

ABSTRACT: Arsenic is a toxic and carcinogenic contaminant of potential concern. Ettringite [Ca6Al2(SO4)3(OH)12·26H2O] has the ability to incorporate oxyanions as a solid solution with SO42-, which could lower the soluble oxyanion concentrations. Therefore, ettringite containing SO42- and AsO43- has been synthesized. Results indicated that AsO43- could substitute for SO42- inside the channels of ettringite in the form of HAsO42-, and a linear correlation existed between Xinitial solution and Xsolid. The thermodynamic characterization of the solid samples was investigated by means of Visual MINTEQ, a freeware chemical equilibrium model, and the solubility product logK of -48.4 ± 0.4 was calculated for HAsO4-ettringite at 25°C. The Lippmann phase diagram and XHAsO4-XHAsO4,aq plot showed that the solid solution series containing arsenate has HAsO4-poor aqueous solutions in equilibrium. These findings can be helpful to arsenate solidification and arsenate leaching modeling projects.

SUBMITTER: Wang W

PROVIDER: S-EPMC5536735 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Synthesis and thermodynamic properties of arsenate and sulfate-arsenate ettringite structure phases.

Wang Weixing W Shao Yan Y Hou Haobo H Zhou Min M

PloS one 20170731 7

Arsenic is a toxic and carcinogenic contaminant of potential concern. Ettringite [Ca6Al2(SO4)3(OH)12·26H2O] has the ability to incorporate oxyanions as a solid solution with SO42-, which could lower the soluble oxyanion concentrations. Therefore, ettringite containing SO42- and AsO43- has been synthesized. Results indicated that AsO43- could substitute for SO42- inside the channels of ettringite in the form of HAsO42-, and a linear correlation existed between Xinitial solution and Xsolid. The th ...[more]

PMID: 28759655

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