(661e) Copper Ion Adsorption By Chitosan and Alginate Gel Nanoparticles and Microparticles for Water Purification Applications

Chitosan and alginate are both low-cost natural carbohydrate materials used for the removal of metal ions from aqueous solutions. This study compared the equilibrium adsorption capacity and adsorption kinetics of chitosan gel nanoparticles, calcium-alginate gel microparticles, chitosan/alginate combination particles and large alginate gel beads for copper (Cu (II)) ions in a batch system at fixed pH. Moreover, the performance of large alginate beads in a batch system compared to that in a continuous flow system was examined.

Results show that the equilibrium adsorption behavior of chitosan and alginate in the low concentration region follows the Langmuir isotherm. Alginate has significantly higher capacity than chitosan, which can be attributed to a comparatively higher density of adsorption sites. Combination particles consisting of alginate microbeads coated with chitosan nanoparticles possess an intermediate maximum adsorption capacity, corresponding to the weight ratio of the alginate and chitosan. Meanwhile, it was observed that the adsorption kinetics of large alginate gel beads were much faster than that of alginate microbeads and combination particles.

For comparison with batch studies, the adsorption behavior of fixed-bed columns packed with large alginate gel beads was studied by varying the column size and volumetric flow rate. The column had shorter active life at a higher flow rate, or at a smaller size. Conventional fixed bed models successfully fit experimental data, allowing prediction of the breakthrough time and estimation of treatment capacity relative to typical commercial ion exchange resins.