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Ammonium–Potassium–Calcium Exchange on Vermiculite and Hydroxy-aluminum Vermiculite

Iowa State University, Dep. of Agronomy, Crop, Soil, and Environmental Science, Ames, IA 50011-1010

View larger version (30K): [in a new window]   Fig. 1. X-ray diffractograms of vermiculite clay.

View larger version (35K): [in a new window]   Fig. 2. X-ray diffractograms of hydroxy-Al interlayered vermiculite (HIV).

View larger version (21K): [in a new window]   Fig. 3. Exchange isotherms for NH4-Ca exchange on vermiculite and hydroxy-Al interlayered vermiculite (HIV).

View larger version (15K): [in a new window]   Fig. 4. Vanselow selectivity coefficients of NH4-Ca exchange on vermiculite and hydroxy-Al interlayered vermiculite (HIV).

View larger version (15K): [in a new window]   Fig. 5. Vanselow selectivity coefficients for NH4-Ca exchange in the presence or absence of K+ (6.0 mM KCl in solution) on hydroxy-Al interlayered vermiculite (HIV).

View larger version (17K): [in a new window]   Fig. 6. Vanselow selectivity coefficients for NH+4-Ca exchange in the presence or absence of K+ (6.0 mM KCl in solution) on vermiculite.

View larger version (22K): [in a new window]   Fig. 7. Relationship between ammonium concentration ratio (CRNH4) and equivalent fraction of ammonium on the exchange phase (ENH4) on the exchange phase of vermiculite in the presence and absence of K (ternary exchange equivalent fractions were calculated utilizing cation-exchange capacity (CEC) as the sum of all three cations, NH+4, K+, and Ca2+, on the exchange phase).

View larger version (21K): [in a new window]   Fig. 8. Relationship between ammonium concentration ratio (CRNH4) and ammonium on the exchange phase (ENH4) of hydroxy-Al interlayered vermiculite (HIV) in the presence and absence of K (ternary exchange equivalent fractions were calculated utilizing cation-exchange capacity (CEC) as the sum of all three cations, NH+4, K+, and Ca2+, on the exchange phase).

View larger version (24K): [in a new window]   Fig. 9. Relationship between ammonium concentration ratio (CRNH4) and ammonium on the exchange phase (ENH4) of vermiculite in the presence and absence of K (ternary exchange equivalent fractions were calculated utilizing cation-exchange capacity [CEC] as the sum of the two cations [NH+4 and Ca2+] on the exchange phase).

View larger version (22K): [in a new window]   Fig. 10. Relationship between ammonium concentration ratio (CRNH4) and ammonium on the exchange phase (ENH4) of hydroxy-Al interlayered vermiculite (HIV) in the presence and absence of K (ternary exchange equivalent fractions were calculated utilizing cation-exchange capacity [CEC] as the sum of the two cations [NH+4 and Ca2+] on the exchange phase).