Polysaccharide-based materials and their adsorption properties in aqueous solution

Polysaccharides (PS) of cellulose, soluble, corn- and maize-derived starches with variable amylose/amylopectin content were cross-linked with epichlorohydrin (EPI) to form polymeric adsorbents. The properties of the cross-linked PS-EPI materials were prepared by varying the synthesis conditions (nature of polysaccharide, temperature, and reagent ratios) to afford network polymer materials with tunable properties. The optimized polymers were obtained at a reaction temperature (50-54 °C) according their yield were characterized using spectroscopic (IR and NMR) methods, and thermal gravimetric analysis (TGA). The textural and adsorptive properties of the polymers were evaluated using nitrogen gas and dye-based methods using p-nitrophenol. Solvent uptake, nitrogen adsorption, and aqueous dye sorption show that the amylose and amylopectin content in the PS-EPI copolymers display a complex relationship with their physicochemical properties. Polymers with greater cross-linking did not show incremental changes in water or dye uptake. Structural variation of the polysaccharide (i.e. branching, molecular weight, and relative amylopectin/amylose content) contributed to the sorption properties by modifying their textural properties and surface chemistry.