BINARY AND TERNARY CATION EXCHANGES: THE EFFECT OF ELECTROLYTE ANIONS ON SELECTIVITY AND ADSORPTION CAPACITY

Rhee, In H.

Environmental Engineering Research 1999;4(3): 195-206.

In H. Rhee^†

Department of Chemical Kngineering, Soonchunhyang University, Asan 336-745, Chungnam

Corresponding Author: In H. Rhee ,

Received: March 13, 1999; Accepted: August 14, 1999.

ABSTRACT

A systematic sludy with the negative!) charged cation exchange resin Amherlile 200 was performed to investigate the inllnenee of anion type on cation exchange A comprehensive data set was obtained lor binary and ternary cation exchanges involving Na. Mg, and /n on a strongly acidic cation exchange resin in electrolyte systems with the single anions, such as chlodde, perchlorate. and sulfate, and with 1:1 mixtures of them at two total cation concentrations t'K't') of n.Os and 0.2 V I he binarv and ternary cation exchange data exhibited internal consistency in that Mg anil /n were selected oei Na to a comparable degree. I his consistency suggests that multi-component cation exchange should be predictable from binary exchange data. fhe binary and ternary cation exchange data also indicated clearly an ellecl of anion type, with reduction in selectivity of Mg and /n relative to Na in the presence of more strongly complexing anions such as sulfate. I he effects of anion in cation exchange may be ascribed in pari to their association with cations in solution. However, consideration of other processes, especially the specitlc interactions ol ions with charged sites, is needed to explain fully the observed dillerenees in calion selectivity under the various solution conditions examined.

Keywords: calion exchange and adsorption | selectivity | strongly acidic cation exchange resin | background electrolyte anion | total cation concentration