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

Abstract

Organic-inorganic ion-exchangers were obtained by incorporation of zirconium hydrophosphate into gel-like strongly acidic polymer matrix by means of precipitation from the solution of zirconium oxychloride with phosphoric acid. The approach for purposeful control of a size of the incorporated particles has been developed based on Ostwald-Freundich equation. This equation has been adapted for precipitation in ion exchange materials. Both single nanoparticles (2–20 nm) and their aggregates were found in the polymer. Regulation of salt or acid concentration allows us to decrease size of the aggregates approximately in 10 times. Smaller particles are formed in the resin, which possess lower exchange capacity. Sorption of U(VI) cations from the solution containing also hydrochloride acid was studied. Exchange capacity of the composites is ≈2 times higher in comparison with the pristine resin. The organic-inorganic sorbents show higher sorption rate despite chemical interaction of sorbed ions with functional groups of the inorganic constituent: the models of reaction of pseudo-first or pseudo-second order can be applied. In general, decreasing in size of incorporated particles provides acceleration of ion exchange. The composites can be regenerated completely, this gives a possibility of their multiple use.

Applications of Ion Exchange Resins in Water Softening

“…Depending on the size, they can be located in different types of pores. Thermodynamic approach to deposition of the particles of one or other size is reported in [57]. a b…”

Ionic Transport in Sol-Gel Derived Organic-Inorganic Composites

“…Since ZHP is the most common modifier for a wide variety of membranes, let us consider the regularity of formation of its particles more detailed. In the framework of the approach [95], embedding of particles into ion exchange polymer is determined by a number of factors. As an example, ZHP deposition with phosphoric acid is considered.…”

Nanoparticles of zirconium hydrophosphate framed with a weakly-acidic cation-exchange polymer

“…Earlier we used strongly acidic polymer matrix for modification with inorganic ion exchangers [14][15][16][17][18]31]. However, weakly acidic ion exchange resins show better selectivity due to additional interaction of functional groups with sorbed ions.…”

“…As an example, the inorganic nanoparticles inserted into ion exchange resins that are available commercially can be mentioned [14][15][16][17][18][19] (subclass i). The sorbents of second subclass involve nanoparticles that are distributed homogeneously in solid phase [20][21][22][23][24].…”

“…Weak bonds of the incorporated nanoparticles with the polymer surface play no key role, because the nanoparticles are retained in the ion exchange resin due to feature of its porous structure -the pore system is an alternation of micro-and mesopores. Moreover, it is incorrect to talk about weak bonds in the case of incorporated aggregates and agglomerates of nanoparticles [14,[16][17][18]31].…”