(415a) Fixed-Bed Study of MG Adsorption on Chitosan Hydrogels

Dyes are popularly used in textile and printing industries.  Most dyes are toxic and even carcinogenic to aquatic life and are harmful to aquatic systems. Industrial waste water containing dyes is difficult to treat as dyes are very stable under such conditions of aerobic digestion,  light, heat and oxidizing agents.

Adsorption technology has been popularly used in the treatment of dye containing waste water. Low cost adsorbents like chitosan are particularly attractive in this application.  However, most of the literature studies used the batch experiments only. In this research, chitosan hydrogels were prepared and examined for the MGO (Malachite Green oxalate or MGO, a basic dye) removal in the batch (equilibrium) adsorption as well as the fixed bed breakthrough (kinetic) experiments. The effect of pH value, dye concentration,  and flow rate were investigated. It was found that the hydrogels present a good adsorption capacity while the fixed bed breakthrough curves are s-shaped in general. Analysis showed that the mass transfer mechanisms are complicated for the kinetic experiments, although it can be roughly fitted to some simple equation like Bohart and Adam model.