In the other word, what parameters will affect on the preference of the soil exchange phase for one cation over another?
However, lyotropic series is a guide, I do not know the quantitative effect of some parameters like the concentration of the cations in the soil liquid phase and the amount of negative charge of the soil particle may influence on the Cation Exchange Selectivity.
Does the type of the mineral in the clay part of a soil may affect on the Cation Exchange selectivity?
Hi,
Many parameters may impact the preference of the soil exchange phase for one cation over another
The selectivity of one cation will be different for each phase (organic matter, oxy-hydroxydes, clay minerals). So your soil composition will have a major impact on the exchange properties of your soil
Looking only at the clay fraction, the type of clay minerals present in the soil will have an impact on i) the amount of cation you can adsorb (different Cation Exchange Capacity) and ii) the distribution of the different cation onto the solid (different selectivity for different clay phases)
Even for a particular type of clay minerals (e.g. smectites) the exchange properties may change with crystal chemistry of the mineral ( attached to this answer: Robin et al. 2015 and references therein, Applied Geochemistry)
If you want to have an idea about "quantitative" effects of some parameters (concentrations, minerals composition of the soil...) you may read the attached papers and maybe perform some modeling as describes in the articles attached
Regards
Article Influence of the ionic strength and solid/solution ratio on ...
Article Assessment of a predictive model to describe the migration o...
Article Ion exchange reactions of major inorganic cations (H+, Na+, ...
Hi,
Many parameters may impact the preference of the soil exchange phase for one cation over another
The selectivity of one cation will be different for each phase (organic matter, oxy-hydroxydes, clay minerals). So your soil composition will have a major impact on the exchange properties of your soil
Looking only at the clay fraction, the type of clay minerals present in the soil will have an impact on i) the amount of cation you can adsorb (different Cation Exchange Capacity) and ii) the distribution of the different cation onto the solid (different selectivity for different clay phases)
Even for a particular type of clay minerals (e.g. smectites) the exchange properties may change with crystal chemistry of the mineral ( attached to this answer: Robin et al. 2015 and references therein, Applied Geochemistry)
If you want to have an idea about "quantitative" effects of some parameters (concentrations, minerals composition of the soil...) you may read the attached papers and maybe perform some modeling as describes in the articles attached
Regards
Article Influence of the ionic strength and solid/solution ratio on ...
Article Assessment of a predictive model to describe the migration o...
Article Ion exchange reactions of major inorganic cations (H+, Na+, ...
Dear Ebrahim,
Your query is ably addressed in the comments by Dr Robin. I would like to add another point, that is selectivity of soil in different cation systems (whether binary, ternary and multication system). I wonder if the following links may be of some help:
http://onlinelibrary.wiley.com/doi/10.1002/jpln.19831460508/abstract
http://www.indianjournals.com/ijor.aspx?target=ijor:jisss&volume=44&issue=1&article=004
http://www.sciencedirect.com/science/article/pii/138151489500041D
In general, the CEC has relatively less impact on cation selectivity of soils compared to others (eg mineral, organic matter, total electrolyte concentration as explained by Dr Robin).
Mr.Ebrahim,Dr.Robin's reply provides a good background information for your question.Apart from the details given by Drs. Robin and Borah,the nature of minerals i.e.,amorous,crystalline and porous determine the selective of cation adsorption/exchange. Inter-layer position like' hexogonal' holes in vermiculite and illite minerals,edge and wedge zones in illitic minerals,internal adsorption sites in porous zeolites etc offer different magnitude of selectivity for cations.Size of ions in hydrated state also influence selective adsorption.Potassium, ammonium and hydronium ions are selectively adsorbed in the wedge or edge zones of illitic minerals compared to hydrated Na or Ca ions.In case of organic colloids /humus both exchange sites and chelation /complexi formation plays role in cation adsorption. Heavy metal cations,because of their existence in more than one ionic form and also in mixed matrix in polluted soils exhibit differential selectivity on adsorption sites.
- Badges
- Science topic
- Similar topics
- Agriculture
- Soil Science
- Soil