pH

Zn2+

Cd2+

kobs (h−1)

R2

kobs (h−1)

R2

5

0.0153

0.8433

0.0125

0.9626

7

0.0178

0.8276

0.0209

0.9516

9

0.0206

0.9681

0.0062

0.8075