The present work is published as "Surfactant modified chitosan beads for cadmium removal" in Internatinal Journal of Biological Macromolecules.

1. Preeti Pal
Indian Institute of Technology,
Kharagpur, India, 721302.
SURFACTANT-MODIFIED CHITOSAN
BEADS FOR CADMIUM
ADSORPTION
1
IIT Kharagpur
11th Asia Pacific Chitin and Chitosan Symposium &
5th Indian Chitin and Chitosan Society Symposium
28-30th September, 2016

2. 2
Chitosan beads (CS beads) preparation
Preparation of surfactant modified beads
(SMCS beads)
Cadmium removal by the CS and SMCS beads
Kinetic study
Characterization of beads
Equilibrium study
pH study
Effect of dose
SEM (Scanning electron microscopy)
FTIR (Fourier transform infrared
spectroscopy)
XRD (X-ray powder diffraction)

3. 3
•Highly toxic and carcinogenic
•Non degradable
•Persistent metal
•Specific density> 5gm/cm3
•PVC products
•Color pigments
•Alloys
•Ni-Cd batteries
•Anticorrosion
agent
•Liver
•Kidney
•Respiratory
system
•Skeletal system
4000-13000
tons/year
agricultural field
and natural water
bodies
Cadmium
Health
effectsUses
Properties
•Half-life:38 years
•Limit :0.003 mg/L (WHO)
•LOD :0.01 mg/L by
ICP/MS;2 mg/L by AAS
(Ades and Kazantzis
1988; Elinder et al. 1985;
Pesch et al. 2000;
WHO, 2008; USEPA, 1999)
Guidelines

4. 4
Reduction
Precipitation
Cementation
Ion exchange
Solvent extraction
 Filtration
Electrochemical
treatment
Membrane technology
Evaporation
Adsorption
•Biosorbents
-Micro-org Based
-Agricutlural Based
•Fly Ash
•Sawdust
•Clay
•Zeolite
•Waste Tea
•Chitosan
Activated Carbon
Synthetic and
naturally
occurring waste
oxides
•Oxide Minerals
•Sludge
•Waste Residue
(Kumar Ravi, 2000; Rathi 2002)

5. •Chitosan was discovered in 1859
by Prof C. Rouget.
• In 1930s and 1940s, 50 patents
filed on application of chitosan.
•Today there are more than 2000
applications.
Special characteristics
•Hydrophilicity
•Biocompatibility
•Biodegradability
•Nontoxicity
•Adsorption properties
•Poly-functionality
Structural properties
• A linear polysaccharide
composed of randomly
distributed β-linked D-
glucosamine and N-acetyl-
D-glucosamine
•Presence of –OH and
–NH2 groups make it
feasible modifications.
• Chitosan is second abundant
biopolymer after cellulose.
• Prepared from chitin
deacetylation
•Obtained by treating outer
skeleton of marine waste with
the sodium hydroxide.
Chitosan
5

6. 6
Chitosan;
different forms
Nano-Fibres
Flakes
Gel Beads
Fibers
Membranes
Nano-particles
Powder

7. 7
3 g CS powder in 250
ml (7 % AA)
CS Solution (stirred for
4 to 5 hours)
Surfactant modified chitosan
beads (SMCS beads)
Cadmium loaded
SMCS beads (CdL-
SMCS Beads)
CS solution was added drop wise
into 150 mL of alkaline
coagulating mixture of
H2O:methanol:NaOH (4:5:1 w/w)
Cd2+ (10 – 100 mg/L)
SDS Solution
Beads taken for weighing 50
Wet weight per bead 2.43× 10-2 gm
Dry weight per bead 4.5 × 10-4 gm
Moisture content (%) 97.71%
% weight (100- moisture
content)
2.09%
Table 1: Properties of prepared beads.

8. 8
CS
Na+
Na+
SDS > CMC Cd2+ Solution
SDS Cd2+Chitosan Beads
CS beads
SMCS beads
CdL-SMCS beads
Na+
Na+
Na+
Na+
Na+
Na+ Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
= ==
CS
Fig. 1. Pictorial presentation of formation of SMCS beads and CdL-SMCS beads from CS beads.
(Das and Pal, 2016)
PICTORIAL PRESENTATION OF FORMATION OF CS BEADS TO
CdL-SMCS BEADS

9. 9
Fig. 2. SEM images of chitosan (CS) beads (a, b), surfactant modified chitosan (SMCS) beads
(c, d), cadmium loaded SMCS beads (CdL-SMCS beads) (e, f).
SEM analysis

10. 10
Fig. 3. FTIR spectra of (a) SDS
powder, (b) Pure Chitosan
powder, (c) SMCS beads, (d)
CdL-SMCS beads.
FTIR
1248, 1468, 1212 asymmetric
stretching of SO4
2-
1085, 1063 symmetric stretching of
SO4
2- C-O
1248, S=O
3439- N-H stretching
1650- C=O from CONH
1425 NH deformation vibrations
1154 CN stretching
1093 –CO vibration in COH
4000 3500 3000 2500 2000 1500 1000 500
1468
815
890
890
1063
1272
1425
580
809
890
1085
1653
3451
%Transmittance
Wavenumber
CdL-SMCS beads
1154
1468
1248
1425
667895
1093
1637
2853
2845
2921
2921
3439
SMCS beads
1154
13761428
1652
2862
2917
3439
CS
1212
630
846
980
10821253
14682845
3461
SDS
2917
(a)
(b)
(c)
(d)
(Wang et al., 2014; Viana et al., 2012)

11. 11
10 20 30 40 50 60 70
Iobs(Counts)
2 Theta (Degree)
CdL-SMCS beads
SMCS beads
SDS
CS
Fig. 4. XRD images of (a) CS powder,
(b) SDS powder, (c) SMCS beads, (d)
CdL-SMCS beads.
XRD
At 2Ɵ18.36o and 22o SDS
and at 20o chitosan showed
high intensity peak due to the
crystalline structure
The intensity of the MMCS
composite has been decreased
due to the disruption of
hydrogen bonds
Decrease in crystallinity
results in improvement of
metal adsorption capacity
(a)
(b)
(c)
(d)
(Wang et al., 2014)

12. 12
0
20
40
60
80
100
120
0
10
20
30
40
50
60
70
80
90
100
10 20 30 40 50 100
%Removal
Cadmium Conc. (mg/L)
CS beads (% R)
SMCS beads (% R)
CS beads (mg/g)
SMCS beads (mg/g)
Capacity(mg/g)
Fig.5. Comparison
of Cd2+ removal by
CS and SMCS
beads.
Cd conc. (mg/L) 10 20 30 40 50 100
CS (% R) 40.08 35.9 22.89 17.35 15.84 14.66
SMCS (% R) 95.01 93.79 90.04 79.45 72.78 59.79
CS (mg/g) 7.41 13.05 12.48 12.62 14.40 29.98
SMCS (mg/g) 17.27 34.10 49.60 54.87 71.67 108.72
(For standard deviation
calculation;n= 3)
Table 2. Comparison of Cd2+ removal performance by CS and SMCS beads.

13. 13
0
10
20
30
40
50
60
70
80
90
100
5 30 60 120 240 480 720 1440 2160 2880
%Removal
Time (min)
0
20
40
60
80
100
120
140
5 30 60 120 240 480 720 1440 2160 2880
Capacity(mg/g)
Time (min)
10 mg/L 20 mg/L 30 mg/L 40 mg/L 50 mg/L 100 mg/L
Fig. 6. Effect of contact
time on the % removal and
capacity of Cd by SMCS
beads. Dose (0.45 g/L).
Optimum time: 10 hrs.
[Cd] % R
10
>90
20
30
~80
40
50
>50
100

14. 14
Cd
Concentration
(mg/L)
Pseudo First Order Pseudo Second Order
qt (mg g−1) k1 (min−1) R2 qt(mg g−1) k2 (g mg−1
min−1)
R2
10 14.01 0.0023 0.948 22.73 4 x10-4 0.997
20 27.183 0.0019 0.966 45.45 2.12 x10-3 0.995
30 44.625 0.0017 0.982 66.66 1.2 x10-4 0.993
40 46.279 0.0021 0.928 83.33 1.34 x10-4 0.997
50 56.042 0.0016 0.982 100.00 8.07x10-5 0.991
100 52.56 0.0069 0.865 125.00 2.82 x10-4 0.997
Table 3. Parameters of the kinetics study of Cd adsorption onto the SMCS beads.
0
20
40
60
80
100
120
0 500 1000 1500 2000 2500
t/qt(ming/mg)
Time (min)
10 mg/L 20 mg/L 30 mg/L
40 mg/L 50 mg/L 100 mg/L
Fig. 9. Pseudo-second order
model for Cd adsorption
onto SMCS beads.
•Adsorption follows pseudo
second order model
•Physiosorption

15. 15
0
20
40
60
80
100
120
140
0 300 600 900 1200 1500 1800 2100 2400 2700
qt(mg/g)
Time (min.)
Cal (10 mg/L) Expl (10 mg/L) Cal (20 mg/L) Exp(20 mg/L) Cal (30 mg/L) Exp(30 mg/L)
Cal (40 mg/L) Exp (40 mg/L) Cal (50 mg/L) Exp (50 mg/L) Cal (100 mg/L) Exp (100 mg/L)
Fig. 10. Plot of qt vs. t for experimental data and theoretical data based on the pseudo-second order model.
Theoretical and experimental curve fitting

16. 16
0
20
40
60
80
100
120
0.09 0.225 0.36 0.45 0.675 0.9 1.125 1.35
%Removal
Dose (g/L)
10 mg/L
40 mg/L
100 mg/L
0
10
20
30
40
50
60
70
80
90
100
4 5 6 7 8
%Removal
pH
% R
Fig.7. Effect of dose on the %
removal of Cd by SMCS beads
(contact time: 10 hours).
Fig.8. Effect of pH on Cd removal
with 30 mg/L Cd conc., dose:0.45
g/L, time: 10 h.
Optimum dose- 0.45 g/L
Optimum pH- 7
(For standard deviation calculation ;n= 3)
100 mg/L>50 % removal
10-40 mg/L >80 % removal
30 mg/L ~90 % removal
ADSORBENT DOSE AND pH STUDY

17. 17
Isotherm Models R2 Linear Equation Equation
Langmuir qm (mg/g) 125 0.996 Ce/qe = 1/(qm.KL) + (1/qm).Ce y = 0.008x + 0.013
KL (L/mg) 0.615
Freundlich KF(mg/g)(L/mg)1/n 46.94 0.855 ln qe = ln KF + (1/n) ln Ce y = 0.2829x + 3.8496
1/n 0.282
0
1
2
3
4
5
6
-2 0 2 4 6
ln(qe)
ln (Ce)
(b)
Fig. 11. (a) Langmuir, (b) Freundlich adsorption isotherm on removal of Cd2+ using SMCS
beads.
Table 4. Values of isotherm constants for Langmuir and Freundlich isotherms and their corresponding R2
values.
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0 20 40 60
Ce/qe
Ce
(a)

18. 18
Adsorbent Capacity
(mg/g)
Dose
(g/L)
Isotherm Reference
Cross-linked chitosan–zeolite
composite
102.15 1.0 L (Zhang et al., 2014)
Raw chitosan >100 4.0 F (Bamgbose et al., 2010)
Chitosan pyruvic acid derivative 98.04 2 L (Boamah et al., 2015)
Chitin 14 6 L (Benguella and Benaissa, 2002)
Banana peels 0.25 10 L (Mohd Said et al., 2015)
Agbani Clay 1.427 100 F (Dawodu et al., 2012)
TiO2 Nanoparticles 29.28 2.5 L (Sharaf El-Deen and Zhang, 2016)
Surface oxidized CNT 11.0 0.5 L (Li et al., 2003)
SMCS beads 125 0.45 L Present work
Table 5. Comparison of the maximum adsorption capacities (qmax) of SMCS beads with other reported
adsorbents for Cd2+ removal.

19. 19
 Chitosan beads successfully modified with the anionic surfactant
SDS.
 The kinetics of the Cd2+ removal on SMCS beads indicates that the
adsorption is physiosorption.
 Equilibrium data fitted well with Langmuir isotherm.
 Maximum adsorption capacity obtained was 125 mg/g .
 Time taken to attain equilibrium was 10 h with optimum dose of
0.45 g/L.
 SMCS beads are economically cheap and environmental friendly
adsorbent.

20. 20
The authors are thankful to IIT Kharagpur for providing the instrumental
facility and financial support.

21. 21
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