الفهرس 
Introduction and literature Review:Only 14 pages are availabe for public view
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Abstract
Chitosan/montmorillonite nanocomposite was prepared using ionic crosslinking method. The method depended on insertion of montmorillonite particles during the crosslinking process of chitosan long chain. Different composites were prepared by changing the molar ratio between the montmorillonite and chitosan. The spectroscopic methods such as FT-IR, XRD, Transmission electron microscope (TEM) and scanning electron microscope (SEM) and Thermogravimetric analysis (TGA) were used in the study of structural properties of the composites. Infra red spectra showed that crosslinking of chitosan with Na-tripolyphosphate (TPP) resulted in the appearance of a new peak at 1253 cm-1 which corresponds to the attachment of TPP molecule to the nitrogen atom in chitosan. In addition FT-IR spectra of chitosan/ montmorillonite composites with different molar ratios showed that the resultant composite exhibited characteristic peaks of both crosslinked chitosan and montmorillonite which means that the resultant materials are composites. XRD also supported these results. TEM micrographs indicated the presence of montomorillonite molecules in the crosslinked chitosan matrix and the prepared composite is in the nano-scale. SEM micrographs gave strong evidence that by increasing the montmorillonite content the porosity and roughness of the nanocomposite were increased.
TGA analysis showed that the thermal stability of the composite increases with increasing montmorillonite ratio in the composite.
The factors affecting the adsorption capacity of the prepared composites such as pH value, initial adsorbent dose and contact time were investigated. The experimentally obtained results showed that the optimum pH value is 5 at which the materials gave maximum adsorption capacity. While the optimum initial dose of adsorbent material is 0.2 gram. The sorption experiment study the effect of contact time showed that montmorillonite reach to maximum adsorption capacity within the first 15 min from the beginning of experiment while the adsorption capacity of crosslinked chitosan beads suggested gradual increase with increasing the contact time until reach to the equilibrium at 120 minutes.
Kinetic studies show a poor pseudo-first order kinetic model fit. Moreover, this kinetic model does not fit well to the whole range of contact time. The pseudo-second order kinetic model considers more likely to predict the behavior over whole range of contact time.