Optimization of conditions for Cu(II) adsorption on 110 resin from aqueous solutions using response surface methodology and its mechanism study

An experimental study on removal of Cu(II) from aqueous solutions using 110 resins was carried out in a batch system. The effects of various operating parameters such as temperature, pH, and initial concentration were analyzed using response surface methodology (RSM). The results showed that the optimal adsorption condition of 110 resin for Cu(II) were 35°C, pH = 5.28, and initial Cu(II) concentration of 0.34 mg/mL. At optimum adsorption conditions, the adsorption capacity of Cu(II) was 336 mg/g, well in close agreement with the predicted value by the model. The apparent activation energy Ea and adsorption rate constant k298K values were 11.80 kJ/mol and 3.92 × 10-5 s-1, respectively. The adsorption isotherms data fitted well with the Langmuir model. Thermodynamic parameters (ΔG, ΔS, ΔH) suggested that the adsorption process was endothermic and spontaneous in nature. Desorption study revealed that Cu(II) can be eluted using 1.0 mol/L HCl solution, which indicated that Cu(II) in aqueous solution can be removed and recovered by 110 resin efficiently. Moreover, the characterization of the resin both before and after adsorption was undertaken using IR spectroscopic technique, scanning electron microscopy, and energy dispersive X-ray spectroscopy.