This document presents a study on using xanthogenated-modified chitosan microbeads (XMCM) to remove methylene blue dye from wastewater. The study characterized XMCM using FTIR, pH, and pHzpc analysis. Batch experiments examined the effect of adsorbent dosage and initial pH on dye removal efficiency. Equilibrium isotherm data fitted well to the Langmuir model, indicating monolayer adsorption. The maximum adsorption capacity of XMCM for methylene blue was determined to be 21.62 mg/g. The study demonstrated the potential of XMCM for wastewater treatment applications.

1. PRESENTED BY
SITI NADZIFAH BINTI GHAZALI
Degree of Bachelor of Science (Hons.) Chemistry
Faculty of Applied Sciences
Universiti Teknologi MARA
SUPERVISOR
MDM. ZURHANA BINTI MAT HUSSIN

2. INTRODUCTION

3. BACKGROUND OF STUDY
• Colored (dye) pollution is one of the contributors to the global problem
which is water pollution (Wang et al., 2011).
• Methylene Blue (MB) is widely use in industry and daily life (Rafatullah
et al., 2010).
• The presence of MB in wastewater gives harm to living organism
including human beings and gives a toxic effect to microorganisms
disease (Cazetta et al., 2011; Hameed and Ahmad, 2009).
Figure 1 : Chemical structure of MB
N
H3C
CH3
S
N
N
CH3
CH3
+

4. BACKGROUND OF STUDY
• Adsorption has been found to be the most favorable technique due to
its potential technique to remove dye (Wang et al., 2011).
• Chitosan is a natural amino polymer which was reported as one of the
more preferable and common adsorbent in removing dye pollutants
from the water body (Crini and Badot, 2008).
• The presence of amine and hydroxyl groups in chitosan makes
chitosan to have strong adsorption ability towards heavy metal and
dyes ( Kannamba et al., 2010)
Figure 2 : Chemical structure of chitosan
O O
OH
O
NH2

5. PROBLEMS STATEMENT
• A few studies were done to treat Methylene Blue (MB) dyes in wastewater but
some of the treatment are not effective, not practical, and expensive and
sometimes produces toxic sludge which required another disposal technique
(Zhu et al., 2012).
• Adsorption of dyes was found to be effective and economical compared to the
use of other conversational techniques (Wang et al., 2011).
• Activated carbon was introduced in the past as the most effective adsorbent to
remove coloring materials (Vargas et al., 2011). However, activated carbon
requires high operating cost (Weng et al., 2009).
• Modified chitosan was proven in removing large amount of MB from waste
water (Wang et al., 2011; Liu et al., 2010; Huang et al., 2011).
• Alternatively, Xanthogentated-Modified Chitosan Microbeads was proposed
as the new alternative adsorbents used to improve the discharged water
conditions.

6. SIGNIFICANCE OF STUDY
• Through this study :
The feasibility of XMCM to remove MB in wastewater would
be revealed.
The chemical process and uptake rate of XMCM against MB
will be assessed and compared to other adsorbents. This will
provide knowledge of the best chitosan-based adsorbent
available in treating polluted wastewater.

7. OBJECTIVES
The intention of this research is to investigate the adsorption capacity
of MB onto XMCM.
The specific objectives of this project include to :
i) To characterize XMCM by FTIR, pHslurry and pHzpc.
ii) To determine the effect of important physicochemical parameters
such as adsorbent dosage and initial pH of MB solution that can
affect adsorption efficiency of methylene blue.
iii) To determine the isotherm study based on isotherm model
(Langmuir and Freundlich model).

8. LITERATURE
REVIEW

9. METHYLENE BLUE
Adsorbent
Maximum
adsorption
capacity
(mg/g)
References
Garlic peel 82.64 (Hameed & Ahmad ., 2009)
Activated carbon-flamboyant pods 874.68 (Vargas et al., 2008)
Sugar beet pulp 714.29 (Vučurović et al., 2012)
Activated carbons of coconut shell
produced by NaOH activation
916.26 (Cazetta et al., 2011)
NaOH-modified rejected tea (N-RT) 242.11 (Nasuha & Hameed, 2010)
Table 1 : Removal of MB by using various type of adsorbent
 MB appears as a dark green powder and yields a blue solution when dissolved
in water (Hameed and El-Khaiary, 2008).
 MB has strong adsorption characteristic onto solid with 668 nm maximum
absorption wavelength (Hameed and El-Khaiary, 2008).

10. MODIFIED CHITOSAN
• Chitosan are not effective to remove MB (cationic dyes) unless
undergo some modification (Liu et al., 2010).
Adsorbent
Optimum
pH
Optimum
dosage (g)
qmax
(mg g-1)
Isotherm
model
references
chitosan-g-poly (acrylic
acid) vermiculite
hydrogel
7 0.025 1685.56 Langmuir
( Liu et al.,
2010)
chitosan-g-poly acrylic
acid
5 0.05 1873 Langmuir
(Wang et
al., 2011)chitosan-g-poly (acrylic
acid) attapulgite
composite
5 0.05 1848 Langmuir
cross-linked succinyl
chitosan
8 0.02 298.02 Langmuir
(Huang et
al., 2011)
magnetic
chitosan/graphene
oxide
10.0 0.05 180.83 Langmuir
(Fan et al.,
2012)
Table 2 : Removal of MB by using various type of modified chitosan

11. XANTHOGENATED
• The principle of preparing cellulose xanthogenate has been clarified by Tan et
al. (2008) is shown in the following reaction:
• Cell-OH + NaOH → Cell-ONa + H2O
• CS2 + Cell-ONa → Cell-OCS2Na
• 2Cell-OCS2Na + Mg2+ → (Cell-OCS2)2Mg + 2Na+
• The purpose of adsorbent modification with xanthate (NaOH + CS2) is to
improve the potential of adsorption capacity of adsorbent onto
adsorbate(Chauhan and Sankararamakrishnan, 2008)
• Xanthate group have been chosen due to the presence of sulfur atoms
(Chauhan and Sankararamakrishnan, 2008)
• sulphur and magnesium content in xanthogenates increase the adsorption
capacities of xanthogenates on heavy metal (Cu2+) (Zhou et al., 2011), .
• The exchange of copper with magnesium also increases the adsorption of
copper (Zhou et al., 2011),

12. METHODOLOGY

13. Sample Treatment
Characterization
FTIR pHslurry
pHzpc
Batch Mode Study
pH Dosage
Isotherm
Study
Figure 3 : Flow chart of research methodology
 Modifications of chitosan were performed by modifying the methods
used by (Kannamba et al., 2010; Wan Ngah et al., 2013; Zhou et al.,
2011).

14. RESULTS
AND
DISCUSSION

15. ADSOBENT CHARACTERIZATION
pHslurry = 9.91
pHzpc = 9.80
When the pH of adsorbate is greater than pHzpc, the surface of
adsorbent will carry negative charge and vice versa (Kamal et al.,
2010).

16. ADSORBENT CHARACTERIZATION
4000 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 650
cm-1
%T
CHITOSAN
XMCM
3273 2875 1744
1637
1560
1453
1375
1229
1147
1033
896
739
707
3187
1730
1654
1429
1225
1145
1035
865
848
739
706
Figure 4 : FTIR spectra of Chitosan before and after treatment

17. ADSORBENT CHARACTERIZATION
Functional group
Wavenumber cm-1
Before treatment
(Chitosan)
After
treatment
(XMCM)
overlapping of O-H and N-H stretching 3273 3187
C-H stretching 2875 2934
NH2 groups 1453 1445
C=S stretching 1429
C-O-C 1033 1034
Table 3 : Characterization of Chitosan before and after treatment

18. ADSORBENT CHARACTERIZATION
4000 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 650
cm-1
%T
T
XMCM
XMCM- MB
3190
1746
1546 1370
1228
1144
706
2934
3566
1638 1464
1038
891
739
3187
1730
1654
1445
1429
1225
1145
1034 865
848
739
706
3451
2941
Figure 5 : FTIR spectra of XMCM before and after MB loaded.

19. ADSORBENT CHARACTERIZATION
Functional group
Wavenumber cm-1
Before MB loaded
(XMCM)
After MB
loaded
(XMCM-MB)
overlapping of O-H and N-H stretching 3187 3189
C-H stretching 2934 2941
NH2 groups 1445 1463
C=S stretching 1429 1370
C-O-C 1034
1037
1017
Table 4 : Characterization of XMCM before and after MB loaded.
Therefore, the main functional groups that participate in
adsorption process onto XMCM were amino and sulfur

20. EQUATION OF ION EXCHANGE
• CTS-OH + NaOH → CTS-ONa+ + H2O
• CS2 + Cell-ONa+ → CTS-OCS2Na+
• CTS-OCS2Na+ + Mg2+ → (CTS-OCS2)2Mg2+ + 2Na+
• (CTS-OCS2)2Mg2+ + 2MB+→ 2(CTS-OCS2MB+) + Mg2+
• CTS-NH2 + MB+ → CTS-NH2MB+
Equation was modified by referring equation given by Tan et al. (2008) and
Chauhan et al. (2008).

21. ADSORBANCE DOSAGE
Figure 6 : Effect of adsorbent dosage on adsorption of MB onto XMCM
 The increase in the adsorption of MB with the adsorbent dosage can be
associated with the increase of surface area and the sorption sites. (Özer et al..,
2007),
 The decreases of the effective surface area explained the reduction in
adsorption capacity. (Özer et al.., 2007),

22. OPTIMUM PH OF ADSORBATE
Figure 7 : Effect of initial pH of MB aqueous
 Chemical reaction between the dye molecules and adsorbent also affects the
adsorption capacity (Han et al., (2011).
 Therefore, the experiment was carried out at pH 4 because the adsorption
capacity of XMCM decreased at the pH higher than pH 4.

23. ISOTHERM MODELS
Figure 8 : General adsorption isotherm plot of MB onto XMCM (adsorbent
weight: 0.01 g, pH: 4, volume: 50 mL, shaking speed: 120 rpm,
temperature: 30 ± 2 "℃" , initial MB concentration: 10 -70 mg L-1,
equilibrium time: 6 hours)
 The isotherm plot shape provides information regarding the interaction
between adsorbate with adsorbent ( Kamal et al., 2010)

24. ISOTHERM MODELS
Figure 10 : Freundlich isothermFigure 9 : Langmuir isotherm

25. SUMMARY OF ISOTHERM
MODEL DATA
Langmuir Freundlich
qmax
(mg g-1)
b
(L mg-1)
R2 KF n R2
21.62 0.13 0.9885 1.15 1.29 0.9351
Table 5 : Summary of Isotherm model data

26. CONCLUSION
AND
RECOMENDATION

27. CONCLUSSION
Adsorbent
Optimum
pH
Optimum
dosage (g)
qmax
(mg g-1)
Isotherm
model
references
N-benzyl mono-
and disulfonate
derivatives of chitosan
3 N/A 219.1 Langmuir
(Crini et al.,
2008)
chitosan-g-poly (acrylic
acid) vermiculite
hydrogel
7 0.025 1685.56 Langmuir
(Liu et al.,
2010)
cross-linked succinyl
chitosan
8 0.02 298.02 Langmuir
(Huang et
al., 2011)
magnetic
chitosan/graphene
oxide
10 0.05 180.83 Langmuir
(Fan et al.,
2012)
Xanthogenated-
Modified Chitosan
Microbeads
4 0.01 21.62 Langmuir This study
Table 6: Removal of MB by using various type of modofied chitosan
 the main functional groups that participate in adsorption process onto
XMCM were amino and sulfur

28. RECOMMENDATIONS
 There are two probabilities that could be tested in the future :
 whether there is a method to be utilized in preserving the OH group
while chitosan modification takes place, or
 use of other chemical during the process of chitosan modification.
 XMCM be used as an adsorbent to anionic dyes
 Removal MB with modified chitosan with xanthate and hydrogel in order
to introduce
 sulfur atoms (xanthation)
 some ionic functional group (in hydrogel) inter alia; sulfonic acid,
hydroxyl, amine and carboxylic acid groups (Liu et al., 2010)
 hydrogel able to adsorb and retain water and solute molecule
because it is has high porous structures and water content which
allow solute to diffuse through hydrogel structure (Liu et al., 2010).

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