2.4 Result and Discussion
33
2.4.2 SEM Outcome
The surface morphology of the three set of chitosan was inspected and presented in
Fig. 2.5. The SEM image of pure chitosan demonstrates a rough, uneven and porous
structure. After cross-linking pure chitosan with epichlorohydrin the surface of the
CR-CS became visible, smooth and non-porous as depicted in Fig. 2.5b. On another
hand, the grafting of the cross-linked leads to a homogeneous surface indicating that
4-aminobenzoic acid was chemically bonded onto the surface of the beads. Hence, the
surface of chitosan was sufficiently enhanced after grafting the cross-linked chitosan.
2.4.2.1 BET Outcome
The BET analysis demonstrates the surface area, pore volume and pore size values
of the various set of beads. As can be seen in Table 2.1, pure chitosan (CS) has a
surface area of 190 m
2 /g, pore volume of 0.406 cm
3 /g and pore size of 41.102 nm.
Also observed is that modified G/CR-CS has the greatest surface area of 237 m
2 /g
and this could provide more available reaction sites for adsorption [1].
Fig. 2.5 SEM of a CS, b CR-CS and c G/CR-CS