Table 4.

Maximum adsorption capacity of some adsorbents for HA removal from aqueous media

Adsorbent	pH	Thermodynamic	Isotherm	Kinetic	qm (mg/g)	Ref.
Magnetic chitosan nanoparticle (MCNP)	4.0	endothermic	Langmuir	Pseudo-second order	32.6	[13]
Chitosan/zeolite composites	4	endothermic	Langmuir	Pseudo-second order	74.1	[15]
Fe3O4@SiO2–PANI	2.0	endothermic	Langmuir	Pseudo-second order	36.36	[30]
MWCNTs	3.0	endothermic	Freundlich	Pseudo-second order	83.66	[32]
MWCNTs-COOH	3.0	endothermic	Freundlich	Pseudo-second order	50.26	[32]
Unburned carbon	3.0	endothermic	Freundlich	-	71.8	[43]
Fly ash	3.0	endothermic	Freundlich		10.7	[43]
Chitosan–ECH bea	6	-	Freundlich	Pseudo-first-order	44.84	[44]
Chitin	2.4	-	Langmuir	-	27.3	[48]
Chitosan	3.07		Langmuir	-	28.8	[48]
Montmorillonite-Cu(II)/Fe(III) oxides	3.1–6.1	-	Langmuir	-	98	[49]
Activated carbon (rice husk)	3.0	endothermic	Langmuir	-	45.4	[50]
Polyethylenimine functionalized magnetic mesoporous silica composite microspheres (MS-PEI)	5.5	-	Freundlich	Pseudo-second order	128.64	[51]
Alumina-pillared clays (Al-PILCs)	3.0	-	Langmuir	-	23.4	[52]
MNPs (Fe3O4)	3.0	endothermic	Freundlich	Pseudo-second order	96.15	This work
SMNPs (silica coated with Fe3O4)	3.0	endothermic	Freundlich	Pseudo-second order	196.07	This work