Environmental Engineering Reference
In-Depth Information
investigators ruled out that the adsorption capacity of the porous particles
was still significantly higher than that of many other carbon-based adsor-
bents and should therefore be considered for treatment of textile effluents.
The adsorption of Rhodamine B by core-shell structured polystyrene-
Fe
3
O
4
-GO nanocomposites was studied by Wang
et al.
[137]. The maxi-
mum adsorption capacity was found to be 13.8 mg g
-1
. he same research
group also investigated the removal of Rhodamine B onto RGO/ZnO com-
posite [145]. The composite showed an excellent recycling performance for
dye adsorption with up to 99% recovery over four cycles. In another study
conducted by Yao
et al.
[138], Fe
3
O
4
/SiO
2
-GO nanocomposite was synthe-
sized by a covalent bonding technique to remove Methylene Blue. Isotherm
data best fitted the Langmuir model with maximum adsorption capacities
of 97.0, 102.6, and 111.1 mg g
-1
at 298, 318, and 333 K, respectively.
Cheng
et al.
[147] developed a three-dimensional chitosan-graphene
nanocomposite with large specific surface area and unique mesoporosity
and used it as an adsorbent to remove Reactive Black 5 from its aqueous
solution. A removal efficiency of 97.5% was obtained with an initial dye
concentration of 1 mg L
-1
. It is worth mentioning that graphene used in that
study was prepared from graphite derived from waste sugarcane bagasse.
The potential of GO-chitosan (GO-CS) composite hydrogel to remove
acidic (Eosin Y) and basic (Methylene Blue) dyes from water was explored
by Chen
et al.
[139]. The equilibrium adsorption capacities were reported
to be 390 and 326 mg g
-1
for Methylene Blue and Eosin Y, respectively. The
investigators also reported that GO-CS hydrogel could be used as a column
packing material to fabricate a continuous water purification process.
A novel magnetic chitosan-GO (MCGO) nanocomposite has been devel-
oped by covalently binding chitosan on the surface of Fe
3
O
4
nanoparticles,
followed by covalent functionalization of GO with magnetic chitosan, by
Fan
et al.
[140]. Simple batch adsorption experiments were conducted to
estimate the adsorption properties of MCGO for Methyl Blue. The linear-
ized Langmuir isotherm model best represented the experimental equi-
librium data. A maximum monolayer adsorption capacity of 95.31 mg g
-1
was recorded. The dye uptake kinetics followed a pseudo-second-order
mechanism. The values of thermodynamic parameters indicated the spon-
taneous and exothermic nature of the adsorption process. The MCGO
could be easily regenerated using 0.5 mol L
-1
NaOH and the adsorption
capacity was about 90% of the initial saturation adsorption capacity after
four adsorption-desorption cycles. In a separate study, Fan
et al.
[141]
have found that MCGO also has extraordinary adsorption capacity and
fast removal rate for Methylene Blue. The maximum monolayer adsorp-
tion capacity was found to be 180.83 mg g
-1
. The adsorption of Methylene
Blue by magnetic β-cyclodextrin-chitosan/GO nanocomposites has also
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