Treatment given

Cd

Pb

Fe

Cu

Ni

Cr6+

Reference

None

65

48

[47]

None

43a

[48]

Na2S

81

[49]

None

10a

[50]

None

55b

[51]

None

18b

[52]

None

11

9

[53]

Acid washed

79

27

[54]

None

14

26

12

This work