3.1 Introduction
49
a reduced adsorption potential because the amine group of chitosan is involved in
the cross-linking process, making it necessary to graft other chemical functionalities
onto the backbone of the cross-linking chitosan beads (Fig. 3.2). In this analysis,
chitosan solution (XB) was cross-linked to glutaraldehyde and then the mixture was
used to create cross-linked beads of chitosan. The cross-linked beads (XXB) were
then grafted with ethylene acrylic acid. FTIR, TGA, XRD and SEM were used in
characterizing the three sets of beads. The impact of adsorption variables on binding
metal ions to GXXB was also investigated upon.
GRAFTING
C
H
C
C
OH
H
H
O
HO
HO
O
N
O
HO
OH
O
NH 2
O
OH
O
HO
OH
O
ETHYLENE ACRYLIC ACID
H
(CH 2 ) 3
CH
CH
HO
HO
OH
O
HO
OH
O
NH 2
OH
O
N
O
HO
OH
O
N
N
CH
(CH 2 ) 3
CH
HO
HO
O
N
CH 3 CH 2 COO
O
HO
OH
O
NH2
O
OH
O
HO
OH
O
(CH 2 ) 3
CH
CH
HO
HO
OH
O
HO
OH
O
NH2
OH
O
N
O
HO
OH
O
N
N
CH
(CH 2 ) 3
CH
n
Fig. 3.2 Structure suggested for glutaraldehyde cross-linking chitosan beads grafted with acrylic
acid ethylene