Response Surface Modeling and Optimization of Ni(II) and Cu(II) Ions Competitive Adsorption Capacity by Sewage Sludge Activated Carbon

Abstract

In this study, response surface methodology (RSM) was used to evaluate the experimental parameter’s effect in the competitive adsorption capacity of Ni(II) and Cu(II) ions using activated carbon prepared from sewage sludge. The metal removal efficiency was optimized toward various parameters using central composite design (CCD) under RSM. The model’s predictions are in good agreement with experimental results (R2 = 0.986, 0.974 and Adj-R2 = 0.960, 0.950 for Ni(II) and Cu(II) ions, respectively). ANOVA results showed that the process was mainly influenced by the Ni(II) concentration and adsorbent dose, whereas the other factors showed lower effects. The optimum Ni(II) concentration, Cu(II) concentration, adsorbent dose, contact time and temperature were found to be 40 mg/L, 40 mg/L, 4 g/L, 100 min and 30 °C. Under optimal conditions, maximum adsorption capacity of both metals (7.48 and 4.04 mg/g, respectively for Ni(II) and Cu(II) ions) was obtained.