Coffee grounds as low-cost adsorbent for the removal of copper (II) and lead (II) from aqueous solutions

This work aims to study the removal of Cu (II) and Pb (II) from aqueous solutions with commercial coffee wastes (coffee grounds). Materials with no further treatment such as coffee residues from cafe may act as adsorbents for the removal of Cu (II) and Pb (II). Coffee ground fraction <200 mu m was used in the experimental research. The effect of pH (2.0, 3.0, 4.0 and 5.0), contact time (15, 30, 60, 90, 120, 150, 180, 300, 480 and 720 min) and initial concentration of Cu(II) and Pb(II) (10 mg/L, 20 mg/L, 30 mg/L, 40 mg/L, 50 mg/L) on the adsorption was studied. The optimum values of the process variables were: contact time, 120-720 minutes; pH, 5.0; initial Cu(II) and Pb(II) concentration 20 mg/L. Equilibrium data fitted well to Langmuir and Freundlich models for Pb (II) and Cu (II) with high R-2 values. Studies have shown that coffee grounds are a suitable adsorbent for heavy metals removal from water.