الدراسـة الحركــية و الثرموديناميــكية لإمتــزاز أيــونات (Ni+2,Co+2,Fe+3,Cr+3 ) من محاليلها المائية على سطــح فوســفات التيتانـــيوم

Thermodynamic and Kinetic Study Of Adsorption (Cr+3, Fe+3, Co+2, Ni+2) Ions From Aqueous Solutions On Titanium Phosphate

The industrial wastewater and another pollutants water were required to the treatment to reused another time. The adsorption has been an importance role between removel methods of different pollutants from water, the aim of this study is to study the ability of titanium phosphate surface for adsorption some poisonous heavy metal ions such as         (Cr⁺³, Fe⁺³, Co⁺², Ni⁺²) from aqueous solutions. The results showed that the adsorption isotherms were similar to Freundlich and Langmuir isotherms (S, L) according to Giles classification.

The effect of the acid function on adsorption process was studied showing that the cations have different effects, as follows:

On titanium phosphate surface (Cr⁺³)  ion is follows:

pH = 5 > 4 > 6 > 3 > 2 > 1

On titanium phosphate surface (Fe⁺³) ion is follows:                                   pH = 4 > 5 > 3 > 2 > 6 > 1

On titanium phosphate surface (Co⁺²& Ni⁺²) ions are follows:                     pH = 5 > 7 > 9 > 3

The adsorption phenomena on titanium phosphate surface was studied at different temperatures in the experimental range (293 – 323)˚K, the results showed that the adsorption of (Cr⁺³&Fe⁺³) ions on titanium phosphate surface decreases with increasing temperature, i.e., exothermic process, while the adsorption of (Co⁺²& Ni⁺²)  ions on titanium phosphate surface increases with increasing temperature, i.e., endothermic process.

The study results showed that the adsorption amount of four cations on

titanium phosphate surface in temperature (303)˚K are follows:

Fe⁺³ > Cr⁺³ > Ni⁺² > Co⁺²

The effect of adsorbent weight and adsorbate ion concentration on adsorption process was studied and the best adsorbent weight was: (0.1)gm and the best adsorbate ion concentration was: (50)ppm.

The kinetics of adsorption were studied according to Lagregrans equation of pseudo first order and pseudo second order to calculate reaction order, the results showed that the adsorption of all cations on titanium phosphate surface follow Lagregran ُs equation of  pseudo second order.

The liquid film diffusion effect and intraparticle diffusion rate effect of adsorbate ions play asignificant role in controlling the kinetics of the adsorption process, and the results showed that the adsorption rate increase with increasing adsorbate ion concentration.