• zeolite supported mono- and bimetallic oxides: promising adsorbents for removal of as(v) in aqueous solutions

    جزئیات بیشتر مقاله
    • تاریخ ارائه: 1392/01/01
    • تاریخ انتشار در تی پی بین: 1392/01/01
    • تعداد بازدید: 620
    • تعداد پرسش و پاسخ ها: 0
    • شماره تماس دبیرخانه رویداد: -
     in this study, synthesis and characterization of novel adsorbents based on natural zeolite (clinoptilolite) supported mono- (fe or al) and bimetallic (fesingle bondal) oxides for adsorption of arsenate from aqueous solution were investigated. batch sorption experiments were carried out at different ph (3.0, 5.0 and 7.0), temperature (298, 318 and 338 k) and initial metal concentration (0.5, 5.0 and 9.5 mg l−1) values. the experimental results showed that aluminum (znasingle bondal) and iron (znasingle bondfe(ii)) modified zeolites enhanced the arsenate uptake significantly. furthermore, bimetallic oxide associated zeolite, znasingle bondalfe(iii), showed highest adsorption capacity as compared to znasingle bondal and znasingle bondfe(ii), indicating that aluminum impregnation can provide more adsorption sites (alsingle bondoh) to as(v) anions. maximum sorption capacities were achieved at ph 5 for zna (0.026 mg g−1), znasingle bondal (1.50 mg g−1) and znasingle bondalfe(iii) (3.86 mg g−1) and at ph 3 for znasingle bondfe(ii) (3.02 mg g−1). the results suggest that as(v) adsorption process is dominantly followed by surface complexation reactions for znasingle bondal and znasingle bondalfe(iii) adsorbents while columbic interactions occur on the surface of znasingle bondfe(ii). dubinin–radushkevich and freundlich isotherm models fitted the equilibrium data better than langmuir isotherm. the gibbs free energy values were found as negative for all sorbents, which indicates the adsorption of arsenate on modified zeolites is feasible and spontaneous.

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