• an intensive study on the magnetic effect of mercapto-functionalized nano-magnetic fe3o4 polymers and their adsorption mechanism for the removal of hg(ii) from aqueous solution

    جزئیات بیشتر مقاله
    • تاریخ ارائه: 1392/01/01
    • تاریخ انتشار در تی پی بین: 1392/01/01
    • تعداد بازدید: 852
    • تعداد پرسش و پاسخ ها: 0
    • شماره تماس دبیرخانه رویداد: -
     a series of mercapto-functionalized core–shell structured nano-magnetic fe3o4polymers (sh-fe3o4-nmps) with different amount of magnetic core were synthesized and characterized by xrd, ea, vsm, tg–dtg and xps. their applications as adsorbents for hg(ii) removal from aqueous solutions were intensively investigated. the adsorption process of hg(ii) by sh-fe3o4-nmps was found highly ph dependent and related to the content of fe3o4 magnetic core in the adsorbents. the optimized content of magnetic core for sh-fe3o4-nmps was found to be at 5.88%. kinetic studies showed that the adsorption of hg(ii) by sh-fe3o4-nmps followed pseudo-second-order model, suggesting a chemisorption process. activation energy (ea) for the hg(ii) removal was found to be 22.1 kj mol−1, indicating that the diffusion process might be the rate-controlled step. thermodynamic studies suggested that the adsorption processes of hg(ii) onto the sh-fe3o4-nmps were endothermic and entropy favored in nature with the enthalpy changes (δhθ) at 7.26–16.54 kj mol−1 and the entropy changes (δsθ) at 27.60–56.78 j mol−1 k−1. the adsorption processes fit the langmuir isotherms well with the maximum adsorption capacities of hg(ii) onto the sh-fe3o4-nmps at 129.9–256.4 mg g−1 with the content of fe3o4 in sh-fe3o4-nmps varying from 0% to 22.37%. the selective adsorption of hg(ii) by sh-fe3o4-nmps can be achieved when ca2+, mg2+, na+ or cu2+ ions coexisted. xrd and xps analyses results of the adsorbents before and after hg(ii) adsorption suggested that hg(ii) ions had been successfully adsorbed onto sh-fe3o4-nmps via coordination interactions, and hg(ii) might be partially reduced to hg2cl2 through solid state redox reaction via charge transport on the surface of the sh-fe3o4-nmps, in which the fe3o4 magnetic core in the adsorbents might play an important role.

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