Fig. 7

The relationship between adsorbent dosage and removal percentage of Pb2+ (a), Cu2+ (b), and Cd2+ (c, d) for limestone (CO3) and calcined limestone (CaO). Experiment conditions for CaCO3: t: 30 min., Ci: pb2+ = 500 ppm, Cu2+ = 100 ppm, and Cd2+ = 50 ppm, pH: 5. Experiment conditions for CaO: t: 30 min., Ci: pb2+ = 1000 ppm, Cu2+ = 500 ppm, and Cd2+ = 150 ppm, pH: 5.