Quantitative modeling of a neutralization and co-precipitation process with ferrihydite for the simultaneous removal of as(V) and Hg(II)

Tatsuya Kato, T. Uchida, M. Yagisawa, S. Hobo, Chiharu Tokoro

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    In this study, quantitative modeling was carried out for the treatment of simulated waste water containing As(V), Zn(II) and Hg(II) as toxic elements, and Fe(III), Na(I) and sulfate as coaxing ions. The objective was to predict the pH and residual concentrations of all the elements in solution after the neutralization/co-precipitation treatment. To accomplish this, the removal mechanism for As(V) and Hg(II) by ferrihydrite precipitation was first investigated for simulated waste water containing only As(V) or Hg(II). From the experimental results, it was confirmed that the removal mechanism involves not only surface complexation but also surface precipitation. However, surface complexation is the main mechanism for As(V) and Hg(II) removal to meet the target levels regulated in Japan. Next, the surface complexation model was constructed for the removal of As(V) and Hg(II) by ferrihydrite. The specific surface area and site density were determined from reference values proposed by Dzombak and Morel (1990). By comparing the experimental and calculated results, it was confirmed that our constructed model could successfully represent the experimental results. Furthermore, the surface complexation model was coupled with chemical equilibrium calculations and applied to the neutralization of simulated waste water containing As(V), Hg(II), Zn(II), Na(I), Fe(III) and sulfate. The constructed model could successfully represent the pH edge for As(V), Hg(II), Zn(II), Fe(III) and SO4 2- removal. In addition, the constructed model could represent the ion balance. Thus, our constructed model is useful to estimate the amount of neutralizer that is needed to achieve a target pH.

    Original languageEnglish
    Title of host publicationIMPC 2016 - 28th International Mineral Processing Congress
    PublisherCanadian Institute of Mining, Metallurgy and Petroleum
    Volume2016-September
    ISBN (Electronic)9781926872292
    Publication statusPublished - 2016 Jan 1
    Event28th International Mineral Processing Congress, IMPC 2016 - Quebec City, Canada
    Duration: 2016 Sep 112016 Sep 15

    Other

    Other28th International Mineral Processing Congress, IMPC 2016
    CountryCanada
    CityQuebec City
    Period16/9/1116/9/15

    Keywords

    • Arsenic
    • Ferrihydrite
    • Mercury
    • Modeling
    • Sulfate
    • Surface complexation

    ASJC Scopus subject areas

    • Geochemistry and Petrology
    • Geotechnical Engineering and Engineering Geology
    • Mechanical Engineering
    • Earth-Surface Processes

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