Table 1 A comparative table to include operation conditions, and removal efficiency

1

{[Cd_1.5(btc)(bibp)·2H₂O] H₂ O}_n

120 min

1000 ppm

10 mg

Pb(II) (53.9%) and Cr(VI) (73.8%)

[57]

2

α-cellulose/chitosan

60 min

60 ppm

1.0 g

Cr(II) (56%), Pb(II) (85%) and Cd (94%)

[58]

3

Non-cytotoxic and magnetic cobalt ferrite nanoparticles

30 min

450 ppm

0.1 g

Pb(II) (82%)

[59]

4

Magnetic activated carbon–cobalt nanoparticles

30 min

500 ppm

0.1 g

Pb(II) (90.6%)

[60]

5

Faujasite zeolite decorated with cobalt ferrite nanoparticles

12 h

140 ppm

1 g

Pb(II) (98.4%)

[61]

6

Multifunctional cobalt oxide nanocomposites

140 min

350 ppm

2.8 g

Pb(II) (86.89%) and Cd(II) (82.06%)

[62]

7

Polypyrrole functionalized, Cobalt oxide Graphene

120 min

400 ppm

0.01 g

Pb(II) (93.08%) and Cd(II) (95.28%)

[63]

8

Cobalt ferrite nanoparticles

60 min

400 ppm

0.1 g

Pb (96%)

[64]

9

Organosulphur-modified biochar

300 min

50 ppm

100 mg

Cd(II) (88%)

[65]

10

Activated carbon cobalt composite

20 min

450 ppm

0.1 g

Pb(II) (85%)

[60]

11

Cobalt ferrite nanoparticles

30 min

150 ppm

10 g

Cr(IV) (50.9%)

[66]

12

Co-DPA

80 min

60 ppm

3 g

Cr(II) (99.5%), Pb(II) (99.5%) and Cd (95.6%)

This study