Monovalent/divalent selectivity and the charge separation concept

The Treatability of Perchlorate in Groundwater Using Ion-Exchange Technology

“…As the alkyl length increases, the selec-tivity for divalent ions decreases. 7 For example, the type I and II resins have a greater affinity for sulfate (a divalent ion) relative to nitrate (a monovalent ion). In fact, triethyl and longer functional group resins prefer nitrate over sulfate and for this reason are referred to as nitrateselective resins.…”

Determination and theoretical evaluation of selectivity coefficients of monovalent anions in anion-exchange polymer inclusion membrane

“…However, integration of K X − I − versusx I − is difficult in some cases, so the average selectivity coefficients are usually obtained from Eq. (1) when the mole fraction of the reference and the competing ions are equal (0.5) in the membrane [25]. The values of averaged K X − I − , reported in the present work, were obtained from the respective ion exchange isotherms atx I − = 0.5.…”

Selective Cesium Adsorptive Removal on Using Crosslinked Tea Leaves

“…Water-soluble molecules were partially eluted, and such small loss had no suppression to the adsorption capacity of CUT, and it was similar to that of CFT. Some conventional cation resins, such as carboxylic acid resin, have less selectivity for monovalent metals [30][31][32]. On the contrary, a decreased amount of hydroxyl groups on crosslinked tea leaves attributed to partial crosslinking and could lead to weaker electrostatic interaction between ion-exchange groups and metal ions.…”