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Lyotropic Series

Ion Exchange

Charge
Source

Electroneutrality

Exchange
Process

Electric
Double
Layer

Exchangeable
Cations

Lyotropic
Series

Soil pH
and Al
Cation
Exchange
Capacity
pH dependent
CEC
Base Saturation

Anion Exchange

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Test
Soils
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Factors Affecting Cation Adsorption
opposite charge magnitude and separation

 

Valence of the ion
higher charge = greater attraction to exchange sites

  Degree of hydration
increases distance between charges - especially Na+

Effective concentration 
Lack of dissociation (H2CO3) or chelation (RCOO-Al3+) lowers real concentration of ion

 

Lyotropic Series
Strength of attraction to surface:

Al3+ > Ca2+ = Mg2+ > K+ = NH4+ > Na+

 

H+ adsorption