Environmental Engineering Reference
In-Depth Information
copolymers of acrylic acid (AA) and crotonic acid (CA). h e authors
explored the ability of the MNPs for removing heavy metal ions (Cd
2+
,
Zn
2+
, Pb
2+
and Cu
2+
) from aqueous solution [127]. Furthermore, they
explored desorption and reuse of MNPs. h e Fe
3
O
4
@APS@AA-co-CA
MNPs were excellent for removal of heavy metal ions such as Cd
2+
, Zn
2+
,
Pb
2+
and Cu
2+
from aqueous solution. h e Fe
3
O
4
@APS@AA-co-CA MNPs
did not signii cantly adsorb metal ions at pH < 2, which suggested that the
adsorbed metal ions could possibly be desorbed in a solution with such pH
values. h e authors investigated dif erent concentrations of H
+
to deter-
mine the best conditions for reusing MNPs. h e concentration of metal
ions increased with increasing H
+
in water but there was little change with
0.1 mol L
−1
H
+
. Meanwhile, the adsorbent was corroded by the H
+
, which
could be seen from the content of the Fe
3+
. h e adsorbent completely dis-
appeared at 2 mol L
−1
H
+
at er 3 h. Considering the desorption ei ciency,
and the reusability cycles of the adsorbents, the initial concentration of 0.1
M H
+
was better than others. h e metal ion adsorption capacity of Fe
3
O
4
@
APS@AA-co-CA MNPs remained almost constant for the 4 cycles, which
indicates no irreversible sites on the surface of Fe
3
O
4
@APS@AA-co-CA
MNPs for desorption with 0.1 mol L
−1
H
+
, and the reusability of the adsor-
bents was satisfactory.
11.10 Conclusions
Magnetic nanoparticles of er a tremendous opportunity to treat waste-
water containing toxic metal ions because of their high surface area, high
physicochemical stability, multifunctionality, ease in coating, and low-cost
of synthesis. Several routes for the synthesis of magnetic nanoparticles
have been developed and practiced
viz.
, co-precipitation, microemulsion,
hydrothermal and thermal decomposition for rapid and highly ei cient
removal of guest molecules from aqueous solutions. However, the co-pre-
cipitation method is one of the most celebrated synthesis routes for mag-
netic nanoparticles due to its low-cost, easy operation, ease in design and
high yield.
Magnetic nanoparticles of er a new vista of separation and purii cation
technology for heavy metals. h ese multifunctional magnetic nanopar-
ticles have been successfully applied for the reduction of toxic metal ions
up to ppb level in treated wastewater. Magnetic nanoparticle loaded with
toxic metal ions in water can be ef ectively recovered and regenerated with
the help of an external magnetic i eld. h e regenerated nanoadsorbent can
be successfully and ef ectively applied for the recycling and treatment of
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