First-order kinetic model

Second-order kinetic model

Measured qeq,exp

[mg/g]

k1 × 102

[min−1]

qeq,cal

[mg/g]

R2

k2 × 104

[g/mg min]

qeq,cal

[mg/g]

R2

Initial pH

3.2

4.88

101.62

0.99

6.27

111.84

0.99

102.09

7

2.44

97.05

0.97

3.86

109.63

0.99

99.96

10

2.31

93.33

0.96

3.67

100.83

0.99

95.95