Recovery of uranium form sea water by adsorption

Abstract

Loading uranium in the form of $UO_2(CO_3)\frac{4}{3}$- in the artificial sea water, the uranium was adsorbed on galena(PbS) and styrene-divinylbenzene copolymer containing T.B.P. (tributylphosphate). The reagent grade galena in powder form had adsorption capacities of 3.5-12.5 mg/g which were consistent with Langmuir isotherm. The adsorption capacities did not vary with the particle size. Galena was reused as an adsorbent up to four time by treating it with dilute HCl. The technical grade galena used as an adsorbent gave the one-third capacities of the reagent grade galena. The treatment with sectone increased the capacities by 10\%, and 20\% increase was obtained by treating it with 2N HCl. The pelletized galena was used for an adsorbent, which was prepared with the rapid hot-pressing technique at 150$^\circ$C and 5 atm. for 5 min.. Its mechanical strength was in the range of 0.1 -0.2 KN/$cm^2$ with the addition of 2\% sulfur, and its total porosity was varied from 0.4 - 0.6. Its adsorption capacities were 0.4 - 2.0 mg/g for 6 - 29 hr., which were one-tenth or one-fifth of those of powder galena. The modified surface pore diffusion model was used for the simulation surface pore diffusion model was used for the simulation of adsorption of the pelletized galena to give the effective axial diffusivity, $10^{-4} cm^2/\min$. Copolymer beads of styrene-divinylbenzene containg T.B.P. were manufactured by adding caprylic acid as a precipitant during polymerization. The T.B.P. content of those beads was 0.2 g/g, which was evaluated from the analysis of methanol-extracted solution. Their surface area, measured with $N_2$ adsorption, was about $50m^2/g$. The uranium adsorption capacities of those copolymer beads were 6 -9 mg/g for the uranium concentration of 23.7 ppm - 95 ppm for 3 hrs.