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synthesized magnetic polymer MWCNT (MPMWCNT) nanocomposites
composed of MWCNTs, poly (1-glycidyl-3-methylimidazoliumchloride)
(an ionic liquid-based polyether) and Fe
3
O
4
nanoparticles. The adsorp-
tion capacity of MPMWCNT for anionic azo dyes, Orange II, Sunset
Yellow FCF and Amaranth, were examined. The effect of solution pH was
investigated and the adsorption kinetics and isotherms were also studied.
It was found that a low pH value favored the adsorption of anionic azo
dyes and the adsorption kinetic and equilibrium data fitted well to the
pseudo-second-order model and Langmuir isotherm, respectively. It was
inferred that the introduction of ionic liquid-based polyether and Fe
3
O
4
moieties significantly improved the adsorption and separation perfor-
mance of MWCNTs.
Ya n
et al.
[112] prepared guar gum grated MWCNTs/Fe
3
O
4
(GG/
MWCNT/Fe
3
O
4
) ternary composite for the removal of Neutral Red and
Methylene Blue. The pseudo-second-order kinetic model provided a
better correlation for the experimental kinetic data in comparison to
the pseudo-first-order kinetic model. The adsorption equilibrium could
be best represented by the Langmuir isotherm model, with maximum
monolayer adsorption capacity of 89.85 and 61.92 mg g
-1
for Neutral Red
and Methylene Blue, respectively. The high adsorption capacity of GG/
MWCNT/Fe
3
O
4
was ascribed to the hydrophilic property of guar gum,
which improved the dispersion of GG/MWCNT/Fe
3
O
4
in the solution,
and also facilitated the diffusion of dye molecules to the surface of CNTs.
GG/MWCNT/Fe
3
O
4
also exhibited a high saturation magnetization of
13.3 emu g
-1
, and could thus be easily separated from the aqueous solution
by applying a suitable magnetic field.
Chang
et al.
[109] developed starch-functionalized MWCTs/iron oxide
composites to improve the hydrophilicity and biocompatibility of MWCNTs.
The as-synthesized MWCNT-starch-iron oxide was used as an adsorbent
for removing Methyl Orange and Methylene Blue from aqueous solutions.
The nanocomposite exhibited superparamagnetic properties with a satura-
tion magnetization of 23.15 emug
-1
and a high removal capacity of 93.7 and
135.6 mg g
-1
for Methyl Orange and Methylene Blue, respectively.
A novel ternary magnetic composite composed of chitosan wrapped
magnetic nanosized γ-Fe
2
O
3
and multi-walled carbon nanotubes (m-CS/
γ-Fe
2
O
3
/MWCNTs) was prepared for the removal of Methyl Orange by
Zhu
et al.
[108]. The adsorption capacity of Methyl Orange onto m-CS/
γ-Fe
2
O
3
/MWCNTs was 2.2 times higher than m-CS/γ-Fe
2
O
3
. he adsorp-
tion reaction followed the pseudo-second-order kinetics, while the adsorp-
tion isotherm was well described by the Langmuir model with a maximum
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