Rates of Sm (III) Adsorption by a Macromolecular Sorbent Impregnated with 2-Ethylhexyl Hydrogen-2-ethylhexylphosphonate

Masahiro TAKAHASHI*, Tamami IKEDA and Tetsuhiro SASAGAWA

Department of Chemistry and Biochemistry, Suzuka National College of Technology; Shiroko-cho, Suzuka-shi 510-0294 Japan
Mie Factory, Prima ham Co. Ltd.; 1 Midai Iga-cho, Ayama-gun, Mie 519-1414 Japan

Studies were conducted on the adsorption rates of samarium by a macromolecular sorbent impregnated with 2-ethylhexyl hydrogen-2-ethylhexylphosphonate(2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester, EHPNA, HR ) using a stirred transfer cell.
The initial adsorption rate of samarium N0 decreased as hydrogen ion concentration [H+] increases at [H+]>0.1 mol m−3, and the hydrogen ion concentration dependence of adsorption rate becomes nearly zero at [H+]0.1 mol m−3. The initial adsorption rate of samarium increased with increasing EHPNA content in the sorbent [HR], and decreased with increasing samarium concentration [Sm] 0T.
The inner particle capacity coefficient ksav calculated from overall capacity coefficient Ksav and outer particle capacity coefficient kFav were proportional to the 2nd power of EHPNA content in the sorbent , and were proportional inversely to the 2nd power of samarium concentration and to the 1st power of hydrogen ion concentration at [H+]4 mol m−3.
The ratio of mass transport resistance of samarium 1/ksav against the overall mass transport resistance 1/Ksav lowered remarkably with increasing pH and EHPNA content in the sorbent.

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