Premium
Influence of Electrolyte Concentration on Quaternary Cation Exchange by Silver Hill Illite
Author(s) -
Thellier Catherine,
Sposito Garrison
Publication year - 1989
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1989.03615995005300030010x
Subject(s) - chemistry , illite , electrolyte , perchlorate , ionic strength , sodium , inorganic chemistry , ion exchange , sodium perchlorate , cation exchange capacity , nuclear chemistry , ion , clay minerals , mineralogy , soil water , electrode , organic chemistry , electrochemistry , geology , aqueous solution , soil science
A study of Na‐K‐Ca‐Mg exchange on specimen illite in a perchlorate background of varying ionic strength is reported. Sodium‐saturated Silver Hill illite was reacted at pH 7 with perchlorate solutions of differing Na/Ca or Na/Mg ratio and total electrolyte concentration (9.2, 5, 3.6, 2 and 1 mol c m −3 ). All soluble and exchangeable cations were measured directly. No effect of the total electrolyte concentration on the total adsorbed charge was observed. The exchange isotherms and Vanselow selectivity coefficients based on the composition data showed that Silver Hill illite exhibited more or less equal affinity for Ca and Mg. Both bivalent cations were slightly preferred to Na in the three more concentrated electrolyte backgrounds, but at concentrations of 2 and 1 mol c m −3 , a slight preference for Na over Ca and Mg was observed. Exchangeable K, which represented 6 to 18% of the total adsorbed charge, decreased with the content of exchangeable Ca or Mg and, at a given bivalent charge fraction, was dependent on the total perchlorate concentration. The clay exhibited a very high preference for K over the three other cations which increased as the content of exchangeable K decreased.