Poly(4-vinylpyridine) gel-coated on silica. High capacity and fast kinetics in uranyl sulfate recovery

Abstract

A new process has been developed for gel-coating a weak-base resin poly(4-vinylpyridine) as a lightly cross-linked thin layer on high surface area silica to produce a granular sorbent, designated as SiO[sub 2]-[PVP[center dot]XQ]. The gel-coating of the resin affords nearly 80% attainment of its theoretical capacity and provides fast sorption kinetics and nearly instantaneous stripping as compared to conventional weak- and strong-base resins which give much lesser values in the sorption of UO[sub 2]SO[sub 4] from dilute aqueous solutions at a relatively high pH ([ge]4). The conventional bead form resins used for comparison are poly(4-vinylpyridine) Reillex HP, nearly 70% quaternized poly(4-vinylpyridine) Reillex HPQ, and a quaternary ammonium-type strong-base resin Dowex-1 [times] 8. The sorption kinetics on SiO[sub 2]-[PVP[center dot]XQ] is found to be diffusion controlled with a high value of 5.4 [times] 10[sup [minus]6] cm[sup 2]/s for the product of distribution coefficient and effective diffusivity.