Kinetic and thermodynamics of adsorption of copper ions(II) on some Iraqi clays

Abstract

The adsorption characteristics of Copper (II) ions on Iraqi attaplugite and flint clays from synthetic solutions have been studied with relate to variations in contact time, solution pH, solution temperature, and adsorbents dose. All experiments were carried out via batch manner. The maximum removal efficiency of copper (II)ions onto attaplugite was 99.945% at (PH ≈ 5, adsorbent dosage was 0.5 g, contact time was 40 minute, initial concentration was 100 mg/L, and temperature 298K), while the maximum removal efficiency of copper (II)ions onto flint clay was 64.322% at (PH≈5,adsorbent dosage0.3 g, contact time 10 minute, initial concentration 100 mg/L and temperature 298K). The copper (II) adsorption on attaplugite clay was fit with Freundlich and Langmuir isotherms, while the copper (II) adsorption on flint clay was fit with Freundlich and D-R isotherms. The copper ions adsorption kinetic onto attapulgite and flint clays were agree with pseudo second order. The thermodynamic values of ΔG° for copper ions adsorption were negative in those processes, suggesting a spontaneously system. The ΔS° values for copper ions adsorption onto attaplugite clay were positive, suggesting an increase of randomness, while the ΔS° values for copper ions adsorption onto flint clay were negative, suggesting an increase of order. The values of ΔH° for copper ions adsorption onto attaplugite clay were positive, suggesting an endothermic process, while the values of ΔH° for copper ions adsorption on flint clay were negative, suggesting an exothermic process. The values of ΔG° and main adsorption energy (E) in this work suggest that copper ions adsorption on attapulgite and flint clays was classified as physisorption. After adjust all the optimum conditions from batch experiments onto synthetic water, we applied the optimum conditions onto the Al-Quds Power Station wastewater sample. The maximum removal efficiency of copper (II) ions onto attaplugite clays was 99.67% (Conc. of copper ions decrease from 97.39 to 0.321mg/L) at (PH≈5,adsorbent amount 0.5g,equilibrium time 40 minute, and temp. 328K), while maximum removal efficiency of copper (II)ions onto flint clay was 39.83% (Conc. of copper ions decrease from 97.39 to 58.59 mg/L) at (PH.≈.5,adsorbent amount 0.3g,contact time 10 minute, and temperature 298K).