The nature of ion exchange selectivity of phenol-formaldehyde sorbents with respect to cesium and rubidium ions

Abstract

The structure of aqua complexes of alkali metal ions Me + (H 2 O) n , n = 1-6, where Me is Li, Na, K, Rb, and Cs, and complexes of 2,6 dimethylphenolate anion (CH 3 ) 2 PhO -selected as a model of the ele mentary unit of phenol formaldehyde ion exchanger with hydrated alkali metal cations Me + (H 2 O) n , n = 0-5, was studied by the density functional method. The energies of successive hydration of the cations and the energies of binding of alkali metal hydrated cations with (CH 3 ) 2 PhO -depending on the number of water molecules n were calculated. It was shown that the dimethylphenolate ion did not have specific selectivity with respect to cesium and rubidium ions. The energies of hydration and the energies of binding of alkali metal cations with (CH 3 ) 2 PhO -decreased in the series Li + > Na + > K + > Rb + > Cs + as n increased. The con clusion was drawn that the reason for selectivity of phenol formaldehyde and other phenol compounds with respect to cesium and rubidium ions was the predomination of the ion dehydration stage in the transfer from an aqueous solution to the phenol phase compared with the stage of binding with ion exchange groups.Keywords: ion exchange selectivity, phenol formaldehyde sorbents, alkali metals, quantum chemical calcu lations.

Extraction and recovery of rare earths by chelating phenolic copolymers bearing diglycolamic acid or diglycolamide moieties

“…28,29 So, phenolic resins have been used for extraction of heavy metals, [30][31][32][33][34][35] lanthanide metal ions, [36][37][38][39][40] and radionuclides. 29,[41][42][43][44][45][46][47][48] It is believed that polymers with a combination of diglycolamide derivatives and phenolic group can improve the existing sorbents system developed for REEs extraction. Therefore, herein we decribed the synthesis of novel phenol based copolymeric resins that incorporate diglycolamides derivatives.…”

Carbon Fabric Reinforced Addition-Cure Phenolic Resins Based on Propargyl and Allyl Ether Functional Novolac Produced

“…To assess the dynamics of the viscosity change after washing the resin, a "viscometric" kinetic constant was used. An exponential equation characterizes viscosity growth in all the investigated resins curing at 140 and 160 °C and can be described with a "viscometric" kinetic constant, k η [24].…”

A Rothmund–Kornfeld model of Cs+–K+–Na+ exchange on spherical resorcinol-formaldehyde (sRF) resin in Hanford nuclear waste

“…This resin has been shown to effectively remove cesium from Hanford waste, even in the presence of high concentrations (6 M) of sodium [2][3][4][5]. This high selectivity is thought to be related to the cation dehydration process at phenol groups on the resin [6]. Other countries around the world are also developing ion-exchange processes around resorcinol formaldehyde resins [7][8][9][10][11].…”