HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Katou, H. Search for Related Content PubMed Articles by Katou, H. GeoRef GeoRef Citation Agricola Articles by Katou, H. Related Collections Soil Models Soil Chemistry Vadose Zone Processes and Chemical Transport

A pH-Dependence Implicit Formulation of Cation- and Anion-exchange Capacities of Variable-charge Soils

Water Quality and Solute Dynamics Group, National Institute for Agro-Environmental Sciences, Kannondai 3-1-3, Tsukuba, Ibaraki, 305-8604 Japan

View larger version (31K): [in a new window]   Fig. 1. Changes in pH, cation adsorption, Qcat, and anion adsorption, Qan, upon addition of a neutral salt to "905" soil, obtained by solving Eq. [5] through [7], [12], and [13] simultaneously. The soil was initially at Ccat = 0.1 molc m-3 with initial pH = 4, 5, 6, 7, or 8. Solid lines represent Qcat (= CEC) and Qan (= AEC) as a function of pH when the electrolyte concentration, C, is kept constant.

View larger version (27K): [in a new window]   Fig. 2. Changes in the net surface charge, qH (= Qan - Qcat), with the electrolyte cation concentration, Ccat, caused by addition of a neutral salt to "905" soil. pHin = initial pH when Ccat = 0.1 molc m-3.

View larger version (32K): [in a new window]   Fig. 3. Comparison of the cation adsorption isotherms in "905" soil, obtained by solving the pH-dependence implicit Eq. [18] (solid lines) and those by simultaneously solving Eq. [5] through [7], [12], and [13] in which CEC and AEC are expressed as a function of pH and the electrolyte concentration (symbols). Dashed lines represent the isotherms obtained from Eq. [18] when the condition Ccat >> [H+] is not always fulfilled. qH = net surface charge of soil (molc kg-1).

View larger version (27K): [in a new window]   Fig. 4. Changes in pH, cation adsorption, Qcat, and anion adsorption, Qan, upon addition of a neutral salt to "H-1" soil, obtained by solving Eq. [5] through [7], [12], and [13]. The soil was initially at Ccat = 0.1 molc m-3 with initial pH = 4, 5, 6, 7, or 8. Solid lines represent Qcat (= CEC) and Qan (= AEC) as a function of pH when the electrolyte concentration, C, is kept constant.

View larger version (25K): [in a new window]   Fig. 5. Changes in the net surface charge, qH (= Qan - Qcat), with the electrolyte cation concentration, Ccat, caused by addition of a neutral salt to "H-1" soil. pHin = initial pH when Ccat = 0.1 molc m-3.

View larger version (30K): [in a new window]   Fig. 6. Comparison of the cation adsorption isotherms in "H-1" soil, obtained by solving Eq. [18] (solid lines) and those by solving Eq. [5] through [7], [12], and [13] simultaneously (symbols). Dashed lines represent the isotherms obtained from Eq. [18] when the condition Ccat >> [H+] is not always fulfilled. qH = net surface charge of soil (molc kg-1).