Table 3 Heavy metal removal by using other adsorbents

Fly ash/iron ore tailing-based geopolymers

Cu²⁺

–

–

–

113.41

[85]

Metakaolin geopolymer

Co²⁺

39.24

–

–

69.23

[113]

Mn²⁺

72.34

Metakaolin-based geopolymer modified with CTAB

Cu²⁺

216

6

0.22

40

[115]

Fly ash/slag-based geopolymers

Cs⁺

114.16

8.98

0.267

15.24

[117]

Metakaolin geopolymer (MKG)

Zn²⁺

–

–

–

74.53

[117]

Metakaolin-based geopolymer

Zn²⁺

39.24

–

–

74.53

[118]

Ni²⁺

42.61

Geopolymer/Alginate hybrid

Cu²⁺

–

–

–

60.8

[120]

Metakaolin-clinoptilolite zeolite-based geopolymer (MK75)

Pb²⁺

–

–

–

261.2

[122]

Geopolymer microspheres

Pb²⁺

100.99

7

–

629.21

[123]

Rice husk/metakaolin-based geopolymer

Cs⁺

–

–

–

50.8

[126]

Metakaolin geopolymer spheres

Cu²⁺

53.95

5.38

0.061

52.63

[129]

Metakaolin geopolymers

NH₄⁺

22.4

30.97

0.173

21.07

[130]

Metakaolin geopolymer

NH₄⁺

19.3

30.3

0.147

19.7

[131]

Acid-treated fly ash

Cu²⁺

–

–

–

207.3

[132]

Multiwalled carbon nanotubes

Cu²⁺

–

–

–

50.3

[133]

Activated carbon

Cu²⁺

–

–

–

43.47

[134]

Composite Chitosan

Ni²⁺

–

–

–

78.10

[135]

Orange peel

Ni²⁺

–

–

–

62.89

[136]

Natural Bentonite

Ni²⁺

–

–

–

50.00

[137]

Na–P Zeolite

NH₄⁺

–

–

–

73.8

[138]

Zeolite X

NH₄⁺

–

–

–

24.30

[139]

Natural Bentonite

Zn²⁺

–

–

–

52.91

[140]

Acid-treated coconut shell activated carbon

Zn²⁺

–

–

–

45.14

[141]

Geopolymer microspheres

Pb²⁺

–

–

–

629.21

[142]

Sepiolite

Pb²⁺

–

–

–

185.2

[143]

Algae marine, non-living biomass

Pb²⁺

–

–

–

126.5

[144]

Montmorillonite-prussian blue hybrid

Cs⁺

–

–

–

57.47

[145]

Surface-modified sewage sludge molten slag

Cs⁺

–

–

–

52.36

[146]

Concn. nitric acid-modified bamboo charcoal

Cs⁺

–

–

–

45.87

[147]