C_i (mg/L)

0.5

1.0

2.5

5

10

25

50

100

q_e (Pb(II))

0.047

0.094

0.235

0.472

0.948

2.372

4.722

9.145

q_e (Cu(II))

0.038

0.076

0.187

0.374

0.738

1.677

3.37

6.629