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