3.2 Experimental
55
The model of intraparticle diffusion is very important as it is the rate determining
step in any liquid adsorption system [3]. This model describes three stages of adsorbate binding process by adsorbent. In step one, binding takes place on the adsorbent
external surface until the external surface is saturated with metal ions. In step two,
the metal ions at the adsorbent surface enter the pores making intense opposition to
dispersion due to crowding. The third step is very slow owning to decreased metal
ions concentration in the solution, and at this stage, equilibrium is reached between
the ions in solution and the adsorbed ions [3]. Intraparticle diffusion model varies
directly with the rate constant and also the square root of time.
q t = k idm
√
t
(3.17)
t is the time (min), k idm (mmol/gmin
1/2 ) is the intraparticle diffusion rate constant.
The slope of the straight-line plot of q t against t
1/2 provides the value of k idm .
3.3 Result
3.3.1 Outcome of XRD
An X-ray diffraction analyser was used to test the crystallinity of the formed GXXB
relative to XB and XXB. Chitosan is said to be crystalline in nature in its original
state and this crystalline characteristic of native chitosan interferes with the effective
adsorption of metal ions. Figure 3.3a–c displays XB, XXB and GXXB diffraction
patterns, correspondingly [3]. A specific feature of 2θ = 20
◦ was noticed in Fig. 3.3a,
b, which agrees to 110 planes of chitosan, since it is feasible to change chitosan and
preserve some of its qualities. However, due to copolymer formation, which proves
indication of positive grafting, there was a small change in the peak in Fig. 3.3c
[2]. In Fig. 3.3c, however, there was a note of a decrease in intensity in that several
crystalline chains have been eliminated during grafting procedure.
3.3.2 SEM Outcome
Following cross-linking and grafting, SEM was used to examine the morphology and
changes of chitosan. SEM images of various set of beads are shown in Fig. 3.4a–c.
Since of the reaction between chitosan and glutaraldehyde, the XXB surface tends
to be more noticeable and smoother relative to XB, and as such glutaraldehyde has
been chemically bonded with chitosan. The grafting of ethylene acrylic acid onto
XXB’s backbone contributes to surface evenness.
55
The model of intraparticle diffusion is very important as it is the rate determining
step in any liquid adsorption system [3]. This model describes three stages of adsorbate binding process by adsorbent. In step one, binding takes place on the adsorbent
external surface until the external surface is saturated with metal ions. In step two,
the metal ions at the adsorbent surface enter the pores making intense opposition to
dispersion due to crowding. The third step is very slow owning to decreased metal
ions concentration in the solution, and at this stage, equilibrium is reached between
the ions in solution and the adsorbed ions [3]. Intraparticle diffusion model varies
directly with the rate constant and also the square root of time.
q t = k idm
√
t
(3.17)
t is the time (min), k idm (mmol/gmin
1/2 ) is the intraparticle diffusion rate constant.
The slope of the straight-line plot of q t against t
1/2 provides the value of k idm .
3.3 Result
3.3.1 Outcome of XRD
An X-ray diffraction analyser was used to test the crystallinity of the formed GXXB
relative to XB and XXB. Chitosan is said to be crystalline in nature in its original
state and this crystalline characteristic of native chitosan interferes with the effective
adsorption of metal ions. Figure 3.3a–c displays XB, XXB and GXXB diffraction
patterns, correspondingly [3]. A specific feature of 2θ = 20
◦ was noticed in Fig. 3.3a,
b, which agrees to 110 planes of chitosan, since it is feasible to change chitosan and
preserve some of its qualities. However, due to copolymer formation, which proves
indication of positive grafting, there was a small change in the peak in Fig. 3.3c
[2]. In Fig. 3.3c, however, there was a note of a decrease in intensity in that several
crystalline chains have been eliminated during grafting procedure.
3.3.2 SEM Outcome
Following cross-linking and grafting, SEM was used to examine the morphology and
changes of chitosan. SEM images of various set of beads are shown in Fig. 3.4a–c.
Since of the reaction between chitosan and glutaraldehyde, the XXB surface tends
to be more noticeable and smoother relative to XB, and as such glutaraldehyde has
been chemically bonded with chitosan. The grafting of ethylene acrylic acid onto
XXB’s backbone contributes to surface evenness.