6. Know the general behavior of adsorption of the following elements: S, P, N, F

Question

6. Know the general behavior of adsorption of the following elements: S, P, N, Fe, Cu, Zn, Pb, Ca, Na, K, Mg, Se, As, Cl. Start with their molecular form… cation or anion.

7. What is a stronger bond, inner-sphere or outer-sphere? Which is a covalent bond?

8. Where would Hg adsorb on SOM?

9. Where does CEC come from in a soil? How about AEC?

10. What would have a higher CEC contribution 1 kg of HA or 1 kg of smectite? What about at high and low pH? What other differences in sorption properties would the two soil components have?

Explanation / Answer

Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface.

It depends on the charge on the atom or molecule

Every atom becomes an anion or cation depending on the ease with which i can reach noble gas configuration

S, P, N, Fe, Cu, Zn, Pb, Ca, Na, K, Mg, Se, As, Cl.

S become S2- and so it adsorbs on positively charged surface

P becomes P3- and so it adsorbs on positively charged surface

N becomes N3- and so it adsorbs on positively charged surface

Fe gets oxidised to Fe3+ and so it adsorbs on negatively charged surface

Cu gets oxidised to Cu2+ and so it adsorbs on negatively charged surface

Zn gets oxidised to Zn2+ and so it adsorbs on negatively charged surface

Pb gets oxidised to Pb2+ and so it adsorbs on negatively charged surface

Ca gets oxidised to Ca2+ and so it adsorbs on negatively charged surface

Na gets oxidised to Na+ and so it adsorbs on negatively charged surface

K gets oxidised to K+ and so it adsorbs on negatively charged surface

Mg gets oxidised to Mg2+ and so it adsorbs on negatively charged surface

Se becomes Se2- and so it adsorbs on positively charged surface

As becomes As3- and so it adsorbs on positively charged surface

Cl becomes Cl- and so it adsorbs on positively charged surface

7) In coordination chemistry, the ligands that are directly bonded to the metal (that is, share electrons), form part of the first coordination sphere and are sometimes called "inner sphere" ligands. "Outer-sphere" ligands are not directly attached to the metal, but are bonded, generally weakly, to the first coordination shell

So inner sphere is stronger bond

8) Mercury is highly associated with soluble organic matter (SOM) and S levels in soil so it is concentrated mainly in the surface layers.

9) Soil Cation Exchange Capacity (CEC):

Soils are composed of a mixture of sand, silt, clay and organic matter. Both the clay and organic matter particles have a net negative charge. Thus, these negatively-charged soil particles will attract and hold positively-charged particles, much like the opposite poles of a magnet attract each other. The relative ability of soils to store one particular group of nutrients, the cations, is referred to as cation exchange capacity or CEC.

Because of the presence of cations in soil we can tune or regulate the anion exchange also to some extent depending on the cation present so AEC can also be controlled/measured.

Related Questions

Navigate

• Browse (All)
• Browse 6
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.