Fabrication and characterization of chitosan / hydroxyapetite nano composites for tissue engineering applications using locally derived chitosan

In this research work (70/30) nanocomposites of Chitosan (CS) biopolymer and Hydroxyapatite (HA) ceramic powder were synthesized by insitu co-precipitation technique at different reflux temperatures, combined with double step stirring. Initially medical grade chitosan was extracted in the laboratory using locally available shrimp species known as Penaeus Monodon. Extraction of chitosan involved four main stages as preconditioning, demineralization, deprotenisation and deacetylation. Further purifications and modifications were done on extracted chitosan to obtain medical grade chitosan. To synthesize the nanocomposite, analytical grade acetic acid, H3PO4 and Ca(OH)2 used as starting materials. At first, chitosan was dissolved in acetic acid and mixed with required amount of H3PO4 acid. Then the chitosan / H3PO4 solution was added drop wise into the highly alkaline Ca(OH)2 suspension. During the addition chitosan precipitated with hydroxyapatite by forming the chitosan/ hydroxyapatite composite. The precipitate was filtered and washed with distilled water. Then the precipitate was subsequently compressed into a cylindrical form under a uniaxial pressure. Synthesized composite was characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The XRD spectrum demonstrated relevance peaks of chitosan and HA in composite. FTIR spectrum of composite showed the characteristics bond energies of chitosan sample and hydroxyapatite sample. SEM images demonstrated a uniform hydroxyapatite particle distribution in the Chitosan matrix. Each characterization techniques confirm the existence of chitosan and HA in the composite. The size of the HA crystals embedded in composite was calculated using Scherrer formula and it was found to be ~80nm to 100 nm. The basic materials properties of the composite are compatible with the properties of biomaterials that are intended to be used in tissue engineering applications. Therefore, it can be concluded that (70/30) nanocomposites of Chitosan biopolymer and Hydroxyapatite ceramic powder of nano size particles have been successfully synthesized with required material propertie

Synthesis and characterization of Chitosan/Hydroxyapatite (70/30) Nano-Composites

In this research work, (70/30) nanocomposites of Chitosan biopolymer and Hydroxyapatite (HA) ceramic powder were synthesized by insitu co-precipitation technique combined with double step stirring. Initially medical grade chitosan was extracted in the laboratory using locally available shrimp specices Penaeus Monodon. Analytic grade acetic acid, H3PO4 and Ca(OH)2 were used as starting materials. At first, chitosan was dissolved in acetic acid and mixed with required amount of H3PO4 acid. Then the chitosan / H3PO4 solution was added drop wise into the highly alkaline Ca(OH)2 suspension. During the addition chitosan precipitated with hydroxyapatite by forming the chitosan/ hydroxyapatite composite. Finally, the suspension pH reached 6.0-6.5 range, after the complete addition of the solution. Synthesized composite was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Xray diffraction (XRD), thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA). The XRD spectrum demonstrated relevance peaks of chitosan and HA in composite. FTIR spectrum of composite showed the characteristics bond energies of chitosan sample and hydroxyapatite sample. Each characterization techniques confirm the existence of chitosan and FLA in the composite. The size of the HA crystals embedded in composite was calculated using Scherrer formula and it was found to be ~55 nm

Study of Adsorption Characteristics of Cadmium into Chitosan biopolymer to be used for waste water treatments

Pollution by heavy metals is a serious threat to aquatic ecosystems because some of these metals are potentially toxic even at very low concentrations. Chitosan, a biopolymer produced from crustacean shells, has applications in various areas, particularly in drinking water and wastewater treatment due to its ability to remove metallic ions from solutions. The purpose of this research work was to study the adsorption of cadmium on chitosan produced from shrimp shells at a laboratory level. Chitosan, with a degree of deacetylation of approximately 70%, was used in the experimental part and the flake sizes were smaller than 0.25mm. Experimental work involved the determination of the adsorption isotherms for each metallic ion in a batch system. The resulting isotherms were fitted using Langmuir model and the parameters of the equation were determined. Kinetic studies of adsorption for metallic ions at different concentrations and with different particle sizes were performed in batch system. Simplified models such as pseudo-first-order, pseudo-secondorder, and intra-particle diffusion equations were used to determine the rate controlling step. The results showed that the adsorption capacity depends strongly on pH and on the species of metallic ions in the solution. Batch adsorption experiments were performed at two differentdegrees of deacetylation (DD) values, time period ranging from 15 minutes to 3 hours and pH of solutions ranging from 3 to 7. The study showed that the solution pH strongly affects the adsorption capacity of chitosan

Thermal compatibility studies of variable body and glaze compositions for glazed clay based cookware applications

This study was focused on the development of a glazed red clay cookware with adequate thermal shock resistance for open flame cooking applications. Thermal compatibility of different red clay and fritted glaze compositions were investigated using thermal expansion and thermal shock resistance. Coefficients of thermal expansion and thermal shock resistance values of red clay bodies with different proportions of quartz were investigated. Commercially available lead free glazes were selected to satisfy the coefficient of thermal expansion and thermal shock resistance requirements. Thermal conductivity, modulus of rupture, and modulus of elasticity of each body and glaze were measured.Based on the test results, suitable red clay body and glaze compositions were selected and actual size cookware samples were fabricated.The red clay body with 25% quartz having a coefficient of thermal expansion of 60.31×10-7 K-1 and a thermal shock resistance of 0.97 kJm-1s-1, and the glazes having a coefficient of thermal expansion in the range of (49-51)×10-7 K-1 and thermal shock resistance in the range of (1.10-1.20) kJm-1s-1 could be effectively used to manufacture a glazed red clay cookware product. Hence it could be concluded that a suitable body composition for glazed cookware could be formulated by incorporating quartz in a certain proportion to kaolinitic type red cla

Extraction and characterisation of montmorillonite Nano Clay from Sri Lankan Clay Deposits

Clay has been a predominant industrial raw material from ancient periods in Sri Lanka. Abundant availability and quality of available clay has been few of the many reasons why clay products have been very popular in the country. Not much has been changed in the technology used in the fabrication of clay products mined from various sources, since ancient time. But with the development of the technology more research has been focused on using the existing minerals of the country for advanced applications. In many recent developments in polymer-clay nano composites, it has been discovered that usage of Montmorillonite clay in a polymer composite can greatly enhance many of its properties. Hence more focus has been given on the isolating of Montmorillonite nano particles which are suited for these composites applications. This research has been focused on extracting Montmorillonite nano particles from already existing clay deposits of the country, which in turn can be used in the synthetization of polymer-clay nano composite. Preliminary analyses were conducted on selected clay deposits to confirm the presence of Montmorillonite and then they were subjected to various processed to increase the clay constituents while removing the impurity contents. Afterward selected specimens were subjected to the Montmorillonite extraction which involved mainly the isolation of this clay mineral from other types. Resultants were then analyzed by using various techniques to confirm the presence of required properties

Characterization of locally available Montmorillonite clay using FTIR technique

Montmorillonite (MMT) is a layered silicate clay which belongs to the smectite clay group with a wide range of applications in medicine, polymer industry, ceramic industry and nano materials. This research is focused on the use of Fourier Transform Infrared Spectroscopy (FTIR) technique to identify and characterize Montmorillonite clay deposits available in the dry zone of Sri Lanka. Apart from identification, FTIR can be used to discover the family of minerals to which the specimen belongs, the nature of isomorphic substituent and the distinction of molecular water from constitutional hydroxyl. Clay samples obtained from several locations within the dry zone of Sri Lanka were purified, treated and subjected to FTIR, X-ray Diffraction (XRD) and Differential Thermal Analysis (DTA). To further strengthen the findings, specimens of commercially available MMT and Bentonite were subjected to the same tests. Peaks of the resultant spectrum were analyzed and compared with published literature. Results revealed that the specimens subjected to the tests contained MMT with kaolinite. In-depth study of absorbance level of each specimen was useful in identifying the exchangeable cations present in MMT. Further study of the spectrum could pave the way for quantitative analysis of these clay minerals

Adsorption of cadmium and lead heavy metals by Chitosan Biopolymer : a study on equilibrium Isotherms and kinetics

Since heavy metal pollution is a significant aspect to aquatic ecosystems, the objective of this research work was to investigate adsorption characteristics of chitosan as an alternative adsorbent material. In this study, chitosan, synthesized from locally available shrimp type “penaeus monodon” was used to observe adsorption characteristics of cadmium (Cd) and lead (Pb) heavy metals from aqueous solution. Batch kinetic experiment studies were conducted for changing initial pH, initial concentration of metal ions, particle size and degree of deacetylation (DD) of chitosan. Simplified models such as, pseudo first order, pseudo second order and intra-particle diffusion models were used to analyze the experimental data. The result showed that the adsorption capacity strongly depends on pH and DD. It was clearly seen that higher adsorption of heavy metals occur at comparatively high pH and high DD. Equilibrium experimental data were analyzed by using two different isotherm models namely, Langmuir and Freundlich. The characteristic parameters for each isotherm and related correlation coefficients were determined by using mathematical modeling software. Isotherms show that adsorption process of Cd and Pb is a heterogeneous process

Removal of heavy metals from wastewater using chitosan

In this research work natural bio polymer “chitosan” was synthesized using locally available shrimp shells and adsorption of chromium by chitosan was studied. Synthesize of chitosan involved four main stages as preconditioning, demineralization, deprotenisation and deacetylation. Chitosan was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). Both characterization techniques confirm the existence of chitosan. The affinity of chitosan for chromium was studied using K2Cr2O7 solution as the heavy metal solution containing Cr (VI) ions. Adsorption of chromium ions by chitosan was investigated under different conditions. The effect of reaction temperature, particle size of chitosan and pH of solution were studied. Amount of chromium absorbed under different conditions was evaluated using atomic adsorption spectroscopy

Characterization of clay deposits in Nachchaduwa area for ceramic fabrication

In this research clay deposits located in the Nachchaduwa area were investigated to identify suitable ceramic fabrication techniques and products. Deposits located in this area are known to be rich in Kaolinite and Montmorillonite (MMT) and other type of phyrophyllite clays. These are known as "Red Clav" and mined to fabricate traditional ceramic ware by traditional techniques. The specimens were collected fr~m tanks located in this area and subjected to Fourier Transform Infrared Spectroscopy (FTlR). X-ray Diffraction (XRD). Differential Thermal Analysis (DTA) and Thermo Gravimetric Analysis (TGA). after purifying them and removing organic compounds. Combination of these techniques with the chemical analysis on selected specimens was employed to accurate identification of the clay specimens. The results were then compared with each other and published literature for the identification. Results showed the presence of MMT, kaolinite. quartz and other type of clay minerals in small quantities; furthermore specimens subjected to chemical analysis revealed that they contain more than 50% quartz by weight. The purified clay specimens were subjected to a Deflocculant Demand Test. which determines the optimum amount of deflocculant needed to prepare a casting slip. but the test showed that these claysare not suitable to prepare a casting slip in fabricating ceramic ware