Table 3.

Comparison of various nano-adsorbents for alizarin dyes removal.

Adsorbent Type	Maximum Adsorption Capacity, mg/g	Contact Time	Optimum pH	Best Fit Isotherm	Adsorbent Dosage, gm	Removal, %	Ref.
ZnO/TiO2	12.5	120 min	8	Langmuir	5.0	84.4–92.9	[7]
Zinc doped WO3 catalyst	NR	10 min	NR	NR	0.4	80	[8]
α-Fe2O3/NiS	NR	NR	5	NR	1.0	88.3	[10]
Activated carbon/γ-Fe2O3 nano-composite	108.6	60 min	2	Langmuir	0.01	99.4	[13]
Poly METAC/Fe3O4 magnetic nanoparticles	NR	2 days	NR	NR	NR	80–96	[14]
Nanocrystalline Cu0.5Zn0.5Ce3O5	NR	5 min	NR	Freundlich	0.2	83%	[15]
PPy-coated Fe3O4 nanoparticles	116.3	60 min	4–5.4	Langmuir	0.1–0.12	78.7	[18]
Chitosan-coated Fe3O4 nanoparticles	40.12	50 min	3	Langmuir	0.1	NR	[19]
2,4-dinitrophenyl hydrazine/Nano 𝛾-Alumina	47.8	60 min	4	Langmuir	0.05	95.6	[36]
MWCNTs/PANI	884.8	50 min	8.5	Langmuir	0.02	N.R	[37]
Fe3O4 nanoparticles	45.8	5 min	5	Langmuir	0.02	99	[42]
CuFe2O4@graphene nanocomposite	145	40 min	3	Langmuir	0.5	95	[38]
Chitosan/ZnO nanorod composite	36.4	27 h	2	Freundlich	0.1	85	[39]
Fe3O4@MCM@Cu–Fe–LDH	121.9	10 min	9	Langmuir	0.03	N.R	[43]
Biosorbent from Mikaniamicrantha	46.5	N.R	2	Freundlich	0.1	N.R	[40]
Green carbon composite-derived polymer resin and waste cotton fibers	104	1day	3	Freundlich	NR	N.R	[44]
NiFe2O4/Polyaniline Magnetic Composite	186	90 min	4-8.6	Langmuir	0.03	96	[41]
SnO2/CeO2 nano-composite	18.5	30 min	3	Freundlich and Langmuir	0.15	96.4	This work

* NR (not reported), (METAC) (methacryloyloxy)ethyl trimethyl-ammonium chloride, DNPH (2,4-dinitrophenyl hydrazine), MCM (Mobil composition of matter), LDH (layered double hydroxides), multi-walled carbon nanotubes (MWCNTs), polyaniline (PANI), poly pyrrol (PPy).