68
3 Adsorption of Pb(II), Cu(II), Ni(II), Zn(II), Cr(VI) …
pseudo-second-order and intraparticle model is higher and closer to one. The order
for the constant rate to decrease (k 2 ) is as follows: Cu(II)(8.22) > Pb(II)(6.78) >
Ni(II)(6.16) > Cr(VI)(5.94) > Zn(II)(4.59) > Cd(II)(4.32) in g/mmol min. K 2 values
indicate that the adsorption process occurred in the sequence from fast to slow,
and that copper has great affinity for the multifunctional group. This means that
the binding of metal ions to GXXB is a pseudo-second-order reaction model, and
the model postulates that the rate limiting stage may be chemical adsorption or
chemisorption involving valence forces by exchange of electrons between metal
ions and GXXB delivers best agreement of data [3].
3.9 Regeneration Studies
Adsorbent regeneration provides (i) metal ions recovery for effective disposal to
prevent secondary pollution (ii) adsorbent reusability (iii) process cost reduction (iv)
recognition of the adsorption mechanism. The spent adsorbent for the metal ions was
washed separately with distilled water after adsorption trial and treated for 180 min
with 0.5 M HCl. Capacity in desorption was calculated by 3.19.
%Desorption =
C e
C o
× 100
(3.19)
The recovered percentage of Cu(II), Pb(II), Ni(II), Cr(VI), Zn(II) and Cd(II) is
99.3%, 99.1%, 98.5%, 99%, 97.6% and 98.3%, correspondingly. With the metal ions,
the reusability of the regenerated GXXB was observed, and the Q m obtained from
the Langmuir model was not affected.
3.10 Conclusion
It explored the possibility of using GXXB as a binding agent for extracting heavy
metal ions from wastewater. The multifunctional groups present in GXXB have
been beneficial in the binding of metal ions even at low pH values, and the binding of
metal ions has been observed as a complex process consisting mainly of chelation,
chemisorption, electrostatic attraction and ion pair formation. GXXB’s water content
was found to be 76.70%, which helps to move metal ions to binding sites. GXXB
could be a good candidate for binding heavy metal ions at industrial level.
3 Adsorption of Pb(II), Cu(II), Ni(II), Zn(II), Cr(VI) …
pseudo-second-order and intraparticle model is higher and closer to one. The order
for the constant rate to decrease (k 2 ) is as follows: Cu(II)(8.22) > Pb(II)(6.78) >
Ni(II)(6.16) > Cr(VI)(5.94) > Zn(II)(4.59) > Cd(II)(4.32) in g/mmol min. K 2 values
indicate that the adsorption process occurred in the sequence from fast to slow,
and that copper has great affinity for the multifunctional group. This means that
the binding of metal ions to GXXB is a pseudo-second-order reaction model, and
the model postulates that the rate limiting stage may be chemical adsorption or
chemisorption involving valence forces by exchange of electrons between metal
ions and GXXB delivers best agreement of data [3].
3.9 Regeneration Studies
Adsorbent regeneration provides (i) metal ions recovery for effective disposal to
prevent secondary pollution (ii) adsorbent reusability (iii) process cost reduction (iv)
recognition of the adsorption mechanism. The spent adsorbent for the metal ions was
washed separately with distilled water after adsorption trial and treated for 180 min
with 0.5 M HCl. Capacity in desorption was calculated by 3.19.
%Desorption =
C e
C o
× 100
(3.19)
The recovered percentage of Cu(II), Pb(II), Ni(II), Cr(VI), Zn(II) and Cd(II) is
99.3%, 99.1%, 98.5%, 99%, 97.6% and 98.3%, correspondingly. With the metal ions,
the reusability of the regenerated GXXB was observed, and the Q m obtained from
the Langmuir model was not affected.
3.10 Conclusion
It explored the possibility of using GXXB as a binding agent for extracting heavy
metal ions from wastewater. The multifunctional groups present in GXXB have
been beneficial in the binding of metal ions even at low pH values, and the binding of
metal ions has been observed as a complex process consisting mainly of chelation,
chemisorption, electrostatic attraction and ion pair formation. GXXB’s water content
was found to be 76.70%, which helps to move metal ions to binding sites. GXXB
could be a good candidate for binding heavy metal ions at industrial level.