| Ion exchanged capacity (mmol/g) | Cu2+ | R2 Freundlisch isotherm | R2 Langmuir isotherm | Ni2+ | R2 Freundlisch isotherm | R2 Langmuir isotherm | Pb2+ | R2 Freundlisch isotherm | R2 Langmuir isotherm |
Duration of ultrasonic irradiation, min | 60 | 2.4 | 0.82 | 0.81 | 0.80 | 0.93 | 0.88 | 2.20 | 0.98 | 0.95 |
45 | 2.19 | 0.84 | 0.82 | 0.77 | 0.94 | 0.90 | 2.1 | 0.97 | 0.96 | |
30 | 1.92 | 0.83 | 0.9 | 0.75 | 0.92 | 0.88 | 2.05 | 0.97 | 0.94 | |
10 | 1.74 | 0.81 | 0.86 | 0.73 | 0.99 | 0.98 | 2.00 | 0.89 | 0.93 | |
0 | 1.66 | 0.80 | 0.88 | 0.71 | 0.99 | 0.99 | 1.92 | 0.89 | 0.98 |