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Relationships Among Electrochemical Properties, Type of Colloid and Adsorbed Cations of Soil and Mineral Colloidal Suspensions
Author(s) -
Rhoads F. M.,
Nash V. E.
Publication year - 1967
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/sssaj1967.03615995003100060013x
Subject(s) - montmorillonite , chemistry , divalent , clay minerals , illite , vermiculite , adsorption , inorganic chemistry , mineral , potentiometric titration , electrochemistry , surface charge , conductance , mineralogy , materials science , ion , electrode , organic chemistry , mathematics , combinatorics , composite material
Potentiometric cation activities, electrophoretic mobilities and specific conductance at variable frequencies were determined on suspensions of five reference clay minerals and five soil clays. The objectives of this work are: (i) to determine the relationship between clay mineralogy and specific conductance with a variable frequency power source, (ii) to determine the interrelationship among the various electrochemical measurements, and (iii) to study the effect of different exchangeable cations on the electrochemical properties. Montmorillonitic minerals with a charge deficiency in the octahedral layer showed the greatest change in specific conductance with increasing frequency. Vermiculite, on the other hand, showed less evidence of a change in conductance with frequency; illite showed no change. This was taken to indicate that a greater proportion of the exchangeable cations on montmorillonite was in the Stern layer whereas the cations on the higher surface charge density clays were distributed between the Gouy and the chemisorbed layer. A Stern layer on the montmorillonite minerals developed to a greater extent for monovalent cations than divalent. The divalent cations were apparently located between the unit layers of the mineral and did not conduct electric current even at high frequencies.