Elements

Adsorbents

Characteristics

Efficiency

References

Fe

Magnetite (Fe₃O₄), Maghemite (γ-Fe₂O₃), α-Fe₂O₃, etc.

Have magnetic characteristic, high surface area, easy separation easy, recovery, inexpensive, eco-friendly

Excellent adsorption capacity

[61] [67] [68] [69]

Mn

manganese (II) chloride (MnCl₂·4H₂O)

High surface area (even up to 7000 m2 g1), high/tunable porosity, and a variety of pore shapes and functions

Good adsorption efficiency in cheap rate

[70] [71]

Zn

Magnesium zinc ferrite Mg_1−xZn_xFe₂O₄

High adsorption capacity in definite pH magnetic characteristics

Good adsorbent

[71]

Ni

Ni (NO₃)₂·6H₂O, N, N-dimethylformamide (DMF)

Limited adsorption capacity, environment friend I and low-cost adsorbent

Increases the rate and amount of adsorption

[72] [73]

Ti

Titanium Oxides (TiO₂), Metatitanic acid (TiO (OH)2, layered titanium oxide (LTO)

Possess photo-catalytic activity, more surface area, are nontoxic, are corrosion-resistant, and are stable

Spontaneous adsorption by nano particles dependent when form oxides

[74] [75] [76]