1

Hydroxyapatite/ Chitosan Biocomposite for Remazol Blue Dyes

Removal

S. Hamzah1*

, M. F. M. Salleh1

1School of Ocean Engineering University Malaysia Terengganu, 21030 Kuala Terengganu,

Terengganu, Malaysia.

sofiah@umt.edu.my, 22788@student.umt.edu.my

Keywords; Membrane,Ultrafiltration, Affinity, Trypsin, Trypsin purification

Abstract: This study aimed to synthesis and characterized hydroxyapatite/ chitosan biocomposite

for Remazol Blue Dyes Removal. Hydroxyapatite was extracted from egg shell and incooporated

with commercial chitosan to improve its mechanical strength and adsorption capacity. The prepared

adsorbent was characterized in term of morphology using scanning electron microscope and the

presence of funtional group in this biocomposite were confirmed by ATR-FTIR. Performance of

hydroxyapatite/ chitosan was evaluted by its efficiency for remazol blue dyes removal. The

observed results show that the developed adsorbent achieved the highest adsorption capacity at

Introduction

Discharged of colored wastewater from the textile industries into near water streams and

river poses severe environmental problems. These chemicals also present a potential human health

risk as some of them have been shown to be carcinogenic. A variety of methods have been

employed for removing dyes such as chemical precipitation, adsorption, cations-exchange, reverse

osmosis, electrodialysis, electrochemical reduction, etc. [1]. Among these techniques,

adsorption can be one of the most effective methods due to its simple operation and flexibility,

lower cost and hence has industrially been preferred [2].

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) is a ceramic calcium phosphate, or bioceramic

that can be functioned as adsorbent for dyes wastewater treatment. Its properties include high

removal capacity, low water solubility, availability, low cost and high stability under oxidizing and

reducing conditions, excellent biocompatibility, bioactivity and chemical stability [3 ][4]. A

number of methods have been used for Hap powder synthesis such as solid state reaction,

hydrothermal reaction, co-precipitation reaction, sol–gel synthesis, mechano chemical synthesis, etc

from different bio-waste like corals, fish scales, eggs, potato peel, banana peel and many more [5].

Natural structural HAp material from these bio-wastes not only provides an abundant source for

novel also inspires investigations to develop biomimetic composites [6].

However, the brittleness and poor performance of mechanical stability of pure HAp limit its

use for various applications. Thus, integration of this compound with polymeric biomaterial is

believed to compensate for the weak mechanical properties of HA and exhibit improved properties,

such as modulus, strength, and stiffness [7]. Chitosan is apotential biopolymerwhich can be

incorporated with hydroxyapatite to improve its efficiency for contaminant removal in wastewater

treatment

The main goal of this research is to perform green preparation of hydroxyapatite/chitosan

adsorbent for remazol blue dyes removal. Nano-structure of hydroxyapatite will be extracted from

egg shell using biomimetic techniques. The best structure of Hap was integrated with chitosan to

build-up a biocomposite. The prepared material has been characterized using scanning electron

microscope, Fourier Transform Infrared Spectroscopy, X-ray diffraction (XRD) and etc. The

2

performance of the prepared adsorbent will be evaluated for remazol blue dyes removal in batch

experiement.

Materials and Methods

All materials used are of analytical grades. Chitosan particle (Sigma Aldrich) was used for

hydrophilic modification of natural hydroxyapatite. Remazol blue dyes G133 was purchased from

Noor Arfa Batik Craft . Di-potassium hydrogen phosphate was purchased from sigma aldrich.

For hydroxyapatite preparation, egg shells were collected from food stall and ‘roti canai’

restaurant and washed using tap water, followed by distilled water to remove any spoil dough,

cooking oil and any organic materials. The shell was then dried in oven at temperature (40°c ±).

before crushed to small size and blended to become a powder. The obtained power was sieved using

250 micron siever and then diluted in HCl to remove any any organic material and to extract the

calcium. About 400ml 0.125M dipotassium hydrogen sulphate solution (pH 10) added to the

mixture and left it for one week in ambient temperature (30°C).

After one week, the white precipitate was filtered by filter paper and rinsed a few times

using distilled water to remove any excess chemicals. This precipitate was drying for 2 hours at

80°C. The result from drying process produced hydroxyapatite in a white solid crust. To perform

modification, hydroxyapatite was integrated with chitosan in acetic acid solution and stirred for

another 8 hours. The white precipitate obtained was filtered using filter and dried at temperature

30°C±. The white crust was produced which called HAp-Chitosan adsorbent. The prepared

adsorbent was the utilized for remazol blue dyes removal at different adsorbent dosage and pH.

Characterization study was also performed in term of morphology and structure (using SEM),

elemental content (using ATR-FTIR) and crystalline structure (using XRD).

Results and Discussions

The characteristics of HAp/Ch adsorbent.

Figure 1 shows the morphology of Hap/Chitosan composite which has spikey structure that

helping in adsorption of Remazol blue removal. The micrograph also shows that composite surface

is rough and has porous structure with holes and small openings on the surface, resulting in this

prepared material which has a good adsorption capacity. The homogeneously distributed pore

structure also supported by the high porosity and high open pore content [8].

Figure 1 Surface morphology of Hap/Chitosan adsorbent

To verify the integrity of the adsorbent, natural Hap and HAp/Ch were characterised by ATR-FTIR,

and the results are shown in Fig. 2. The band The adsorption band at 3444 cm−1

in natural Hap

corresponding to the stretching vibration of hydroxyl group (–OH) which shift to 3386 cm−1

after

coordination with chitosan, indicated that -OH group involved in the HAp-chitosan complexation.

The band at 1644 cm−1

is attributed to asymmetrical stretching vibration of carboxyl (C=O) [9] and

after coordination, the stretching vibration shift to 1650 cm−1

demonstrating that carboxyl group

also involve in the integration process.

3

(a) (b)

Figure 2 ATR-FTIR spectra of (a) Natural Hap and (b) Hap/Chitosn biocomposite

The absorption bands observed around at 1035, 1063, 961, 890, 569 and 562 cm-1 in both native

and Hap composite correspond to a phosphate group in HAp while the stretching band around 1456

and 1407 cm-1 indicated the presence of carbonate group in this adsorbent.

The effect of adsorbent dosage on blue dyes removal

The effect of adsorbent dosage on the Remazol blue dye removal was carried out by using

different dosages from 20 mg up to 70 mg and the result of removal efficiency displays in Figure 3.

According to the Figure 3, the prepared Hap/Chitosan composite has high potential for dyes

removal when most dosage used can remove the blue dyes more than 80% efficiency except for

adsorbent dose at 70 mg, where the removal efficiency only around 58%.

Figure 3: Removal efficiency of blue dyes at different dosage

The most optimum adsorbent dose for dye removal in the aqueous solution is at 60 mg when the

removal efficiency achieved 95 %. At this point, the adsorption capacity achieved maximum

removal due to the high external surface area of the adsorbent and available site for dyes binding,

consequently a better adsorption could be performed. However, the excess of Hap/Chitosan (at

dosage of 70 mg) used was reduced due to the more densely packed interlayer could make it

difficult to adsorbed dyes.

The effect of pH on blue dyes removal

The effect of pH on remazol blue dyes removal displayed in Figure 4. The removal

efficiency for pH 4 was at 59% where this solution is slightly strong acid.

Figure 4: Removal efficiency of blue dyes at different pH

The removal efficiency of the dye increased at pH5 with comparative difference about 12% and this

result might be explained due to high acidic solution (pH 4) of dyes make it difficult to be adsorbed.

At the pH 6, the removal efficiency was sharply increased up to 95% removal efficiency (optimum

4

) due to protonation of –NH2 groups of chitosan by H3O+ ions in slightly acidic solution which

yields positively charged –NH3+ groups [8]. Further increased of pH tend to reduction of removal

efficiency of blue dyes.

The result might be explained due to high OH ions accumulated on the adsorbent surface. Thus,

electrostatic interaction between negatively charged adsorbent surface and anionic dye molecules

was reduced, thus decreased the adsorption of dye molecule on the surface of Hap/Chitosan.

Conclusions

This study was successfully utilized the eggshell for hydroxyapatite synthesis and integration

of chitosan was proved the improvement of this biocomposite for blue dye removal. Optimum

removal efficiency obtained at pH 6 dyes solution with 60g dosage of adsorbent.

References

[1] Mohan, D and Singh, K P (2002) Single- and multi-component adsorption of cadmium and

zinc using activated carbon derived from bagasse—an agricultural waste. Water Research

36(9) 2304-2318.

[2] Rengaraj, S, Yean, K H, Kang, S Y, Lee, J U, Kim, K W, Moon S H (2002) Studies on

adsorptive removal of Co(II) Cr(III) and Ni(II) by IRN77 cation-exchange resin. J. Hazard.

Mater. Vol. 92, 2, 185–198.

[3] Huang, Y-C, Hasiao, P-C, Chai, H-J (2011) Hydroxyapatite extracted from fish scale:

Effects on MG63 osteoblast-like cells. Ceramics International 37, 1825–1831.

[4] Mondal, S, Bardhan, R, Mondal, B, Dey, A, Mukhopadhyay, S S, Roy, S, Guha, R, Roy, K

(2012) Synthesis, characterization and in vitro cytotoxicity assessment of hydroxyapatite

from different bioresources for tissue engineering application, Bull. Mater. Sci., Vol. 35, No.

4, 683–691.

[5] Mondal, S and Mondal, B (2012) Studies on processing and characterization of

hydroxyapatite biomaterials from different bio wastes, Journal of Minerals & Materials

Characterization & Engineering, Vol. 11, No.1, 55-67.

[6] Gumisiriza, R, Mshandete, A M, Rubindamayugi, M S T, Kansiime, F, Kivaisi, A K (2009)

Nile perch fish processing waste along Lake Victoria in East Africa: auditing and

characterization, Afr. J. Environ. Sci. Technol. 3, 13–20.

[7] Khanna, R, Katti, K S, Katti, D R (2010) In situ swelling behavior of chitosan a

polygalacturonic acid/hydroxyapatite nanocomposites in cell culture media. Int. J. Polym.

Sci. 1-12.

[8] Nguyen, V C and Po, Q H (2014) Preparation of chitosan coated magnetic hydroxyapatite

nanoparticles and application for adsorption of reactive Blue 19 and Ni2+

ions. The Scientific

World Journal, 1-9.

[9] Hamzah, S, Ali, N, Mohammad, A W, Ariffin, M M, Ali, A (2012) Design of chitosan/PSf

self-assembly membrane to mitigate fouling and enhance performance in trypsin separation.

Journal of Chemical Technology and Biotechnology 87(8), 1157-1166.

Acknowledgement

The authors wish to express their sincere gratitude to the School of Ocean, Universiti Malaysia

Terengganu for their cooperation and support.