Application Of Some Thermodynamic Parameters Of Zinc Adsorption With Four Soil Samples From North Of Iraq

Abstract

Adsorption is one of the most important chemical process in soil . which determine the availability of nutrient elements to plant , while sorption isotherms provide useful information about sorption capacity , binding energy of adsorbed element and distribution coefficient in soil solution .Adsorption data can be used to determined thermodynamic parameters . An experiment was conducted with four soils samples belong to four Iraqi province in north of Iraq, Kirkuk , Duhock , Ninava and Erbile , to evaluate zinc adsorption in these soils using Langmiur and Freundlich equations . Depending on adsorption results data , the following thermodynamic parameters were determined : K˚ , G˚ , H˚ and S˚ . Results showed that both Langmiur and Freundlich liner equations succeed in description of zinc adsorption in these soils by determination coefficient R2 ranged from (0.90 – 0.98) and (0.83 – 0.97) respectively . The values of Dynamic equilibrium constant K˚ increased as temperature increased from C˚ to C˚ in all of soils . The values of G˚ at C˚ and C˚ were negative and ranged from ( -. to -.) K.J.mole- and (-. to -.) K.J.mole- respectively . The values of H˚ and S˚ were positive and ranged between ( . - .) K.J.mole- and (. - .) J.mole- respectively . Zinc adsorption in these soils is spontaneous because of the negative values of G˚ and spontaneity increased as temperature increased. Zinc reaction in these soils is endothermic because of the positive values of H˚ . And a randomness combine zinc adsorption in these soils because of the positive values of S˚ .