Silicate removal in aluminum hydroxide co-precipitation process

Chiharu Tokoro, Shinya Suzuki, Daisuke Haraguchi, Sayaka Izawa

    Research output: Contribution to journalArticle

    10 Citations (Scopus)

    Abstract

    The removal mechanisms of silicate using an aluminum hydroxide co-precipitation process was investigated and compared with an adsorption process, in order to establish an effective and validated method for silicate removal from wastewater. Adsorption isotherms, XRD and FT-IR analyses showed that silicate uptake occurred by adsorption to boehmite for initial Si/Al molar ratios smaller than two, but by precipitation of poorly crystalline kaolinite for the ratios larger than two, in both co-precipitation and adsorption processes. Silicate was removed by two steps: (i) an initial rapid uptake in a few seconds; and (ii) a slow uptake over several hours in both processes. The uptake rate in the first step was higher in the co-precipitation process than in adsorption process, presumably due to increased silicate adsorption to boehmite and rapid precipitation of kaolinite. These results suggest that silicate removal using aluminum salts could be effectively achieved if the pH adjustment and aluminum concentration are strictly controlled.

    Original languageEnglish
    Pages (from-to)1084-1096
    Number of pages13
    JournalMaterials
    Volume7
    Issue number2
    DOIs
    Publication statusPublished - 2014

    Fingerprint

    Aluminum Hydroxide
    Silicates
    Hydrated alumina
    Coprecipitation
    Adsorption
    Kaolin
    Aluminum
    Kaolinite
    Adsorption isotherms
    Wastewater
    Salts
    Crystalline materials

    Keywords

    • Adsorption
    • Aluminum hydroxide
    • Boehmite
    • Co-precipitation
    • Kaolinite
    • Sorption density

    ASJC Scopus subject areas

    • Materials Science(all)

    Cite this

    Silicate removal in aluminum hydroxide co-precipitation process. / Tokoro, Chiharu; Suzuki, Shinya; Haraguchi, Daisuke; Izawa, Sayaka.

    In: Materials, Vol. 7, No. 2, 2014, p. 1084-1096.

    Research output: Contribution to journalArticle

    Tokoro, C, Suzuki, S, Haraguchi, D & Izawa, S 2014, 'Silicate removal in aluminum hydroxide co-precipitation process', Materials, vol. 7, no. 2, pp. 1084-1096. https://doi.org/10.3390/ma7021084
    Tokoro, Chiharu ; Suzuki, Shinya ; Haraguchi, Daisuke ; Izawa, Sayaka. / Silicate removal in aluminum hydroxide co-precipitation process. In: Materials. 2014 ; Vol. 7, No. 2. pp. 1084-1096.
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