Abstract:
In this study, different molecular weights of chitosan were prepared by hydrolysis reaction with hydrogenperoxide 4% and 15 %(v/v) for 6 and 24 hours. Hydrolyzed chitosan with different molecular weights obtained from the hydrolysis reaction were 480000, 130000, 69000 and 140000 respectively. Hydrolyzed chitosan with different molecular weights were used to modify Montmorillonite (MMT). The results found that interlayer of modified MMT slightly increased. In addition, octadecylamine was used to enhance the interlayer separation of MMT. The results found that using octadecylamine and hydrolyzed chitosan at molecular weight 69000 imparted highest interlayer separation. As a result, modified MMT using octadecylamine and hydrolyzed chitosan at molecular weight 69000 was used to prepare chitosan/modified MMT composites with various ratios of chitosan and modified MMT. The composites were used as reactive dye adsorbents. The results showed that at pH of dye solution in range 4-6, increasing modified MMT ratio and amount of adsorbent improved the reactive dye adsorption efficiency. Moreover, the adsorption isotherm of dye adsorption followed both the Langmuir and Freundlich models.