Chemistry Reference
In-Depth Information
Fig. 5.22
Model for interaction between the Pb(II) and graft copolymer: (A) at normal pH, (B) at
highly acidic pH [
219
]
grafting. Srivastava and Behari [
116
] synthesized GG-g-PNVP and evaluated its
adsorption on heavy metal ions Cu
2+
,Ni
2+
,Zn
2+
,Pb
2+
, and Hg
2+
; it was concluded
that the graft copolymers enhanced the adsorption amount by 279.4 % (Cu
2+
),
240.7 % (Ni
2+
), 207.1 % (Zn
2+
), 367.2 % (Pb
2+
), and 433.3 % (Hg
2+
) in contrast to
GG. Behari and coworkers [
59
] prepared XG-g-PAMPS graft copolymer, and its
adsorption capacity on Cu
2+
,Pb
2+
,Ni
2+
,Zn
2+
, and Hg
2+
ions was enhanced by
382.2 %, 353.9 %, 356.8 %, 292.0 %, and 262.3 %, respectively, and the retention
capability was improved. The adsorption capacity is proportional to the graft ratio.
The grafting ratio may be controlled by altering the graft reaction condition and the
dosage of monomers, and the type of gum has obvious effect on it. For a gum with
low reaction activity such as cashew gum or higher viscosity, the grafting ratio
usually is low. By controlling the graft parameter, the solubility of the graft
copolymer was decreased, and this is favorable to its application for wastewater
treatment [
138
]. The GG-g-PEA graft copolymers shows ideal adsorption
properties to Cd
2+
ions than guar gum [
165
], and the adsorption capability can be
adjusted by the grafting ratio. Singh et al. also proved the
Cassia grandis
seed
gum-graft-poly(methylmethacrylate) has stronger combination action with the
Pb(II) ions than the gum (Fig.
5.22
)[
219
].
