Effect of the porous structure of polymer on the kinetics of Ni2+ exchange on hybrid inorganic-organic ionites

Abstract

Hybrid organic-inorganic ion exchangers are obtained by incorporating amorphous zirconium hydrophosphate into the gel of strong acidic cation exchange resin. Hybrid organic-inorganic ion exchangers are obtained by modifying strong acidic cation exchange resin with amorphous zirconium hydrophosphate. The synthesized materials are studied by standard porometry contact. It is found that raising the inorganic component content to 34 wt % diminishes the microporosity of the samples and simultaneously enhances the of meso and macropore volume. Experiments establish that modification of a polymer matrix lowers the self diffusion coefficient of Ni 2+ from 8.1 × 10 -12 to 2.4 × 10 -12 -4.1 × 10 -12 m 2 s -1 ; nevertheless, an inorganic ion exchanger minimizes the inhibitory effect of co ions on the Ni 2+ → H + exchange rate. One possible mechanism for of filling of the matrix by with particles of zirconium hydrophosphate is discussed.

Formation of Zirconium Hydrophosphate Nanoparticles and Their Effect on Sorption of Uranyl Cations

“…Porous structure of gel-like ion exchanges provides location for incorporated particles. The structure, which is formed during swelling, involves clusters (up to 20 nm) and smaller channels between them [ 38 – 42 , 55 – 57 ], where functional groups are located. Larger pores (several tens and even hundreds of nanometers) are voids between gel regions.…”

“…In some cases, additionally sorbed ZrOCl 2 electrolyte was removed from the resin by washing with 0.01 M HCl solution before ZHP precipitation. Marking of the samples as well as the modification conditions, which were varied in opposite to [ 38 – 42 ], are given in Table 1 .…”

“…At the same time, sorption on these materials is slow. In order to improve selectivity of strongly acidic resins towards Ni 2+ , Cd 2+ , and Pb 2+ , they were modified with zirconium hydrophosphate (ZHP) [38–44]. The inorganic sorbent shows high selectivity towards toxic cations [45, 46], particularly U(VI) [46, 47] due to formation of complexes with functional groups [48].…”

“…No sufficient deterioration of sorption rate was found for the composites containing non-aggregated nanoparticles [38, 39]. At the same time, particles of micron size slow down ion exchange [41].…”

“…The rate of ion exchange on the composites based on ion exchange resin depends on size of incorporated ZHP particles [ 38 , 39 , 41 ]. No sufficient deterioration of sorption rate was found for the composites containing non-aggregated nanoparticles [ 38 , 39 ]. At the same time, particles of micron size slow down ion exchange [ 41 ].…”