Using the Equilibrium and Thermodynamic Parameters of Copper Adsorption in some Calcareous Soils | ||
| Assiut Journal of Agricultural Sciences | ||
| Article 21, Volume 47, 6-2, December 2016, Pages 602-614 PDF (576.6 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ajas.2017.2798 | ||
| Abstract | ||
| Ten different soil samples from Basrah and Messan governorates of southern Iraqi were used to study the mechanism of copper (Cu) adsorption. Copper was added at 0 , 4 , 8 , 16 and 32 mg Cu kg-1 soil and two salts (0.01 M CaCl2 and 0.01 M NaCl) with two temperature (25±1 C° and 45±1 C°). Copper adsorption was tested using isothermal equation parameters of Langmuir, Freundlich and D-R as well as thermodynamic parameters (K°, ΔG°, ΔH° and ΔS°). The results showed that the isotherm equations that give the best description of copper adsorption were in the following order: Langmuir > D-R > Freundlich according to their (R2) values. The value of activity energy (E) which ranges from 8.006 – 15.823 kJ mol-1 showed that the copper adsorption is an ionic exchange reaction. The value and sign of ΔG° of copper adsorption in the studied soils exhibit that it is a spontaneous process and increases with increasing the temperature. For the positive ΔH° values, Cu at sorption is considered an endothermic reaction and the positive ΔS° indicates the degree of randomness between the solid and liquid phases. There is not any clear effect of soil properties. But there is a general effect of whole soil properties on the calculated parameters. The results also showed that the amount of adsorbed Cu under using 0.01 M CaCl2 on adsorption sites was lower compared to 0.01 M NaCl | ||
| Keywords | ||
| Adsorption; equilibrium; Thermodynamic; copper | ||
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