Polysaccharide-based cationic hydrogels for dye adsorption

With advances in soft material design and engineering, naturally resourced polysaccharides have frequently been used to construct hydrogels because of their unique properties such as renewability, biodegradability and biocompatibility. In this work, we use a water-soluble microbial polysaccharide, salecan as a trapped natural polymer, poly(acrylamide-co-diallyldimethylammonium chloride) (PAD) as a functional matrix to prepare salecan/PAD hydrogels through a facile one-pot method. We employed a variety of spectroscopic techniques to probe the physicochemical properties of the designed hydrogels. The results demonstrated that salecan not only tuned the polarity of the PAD hydrogels, but also endowed them with adjustable water content. Subsequently, the adsorption performance of these hydrogels to methyl orange (MO) dye was investigated in detail. It was found that the salecan/PAD had the ability to remove MO from the surrounding aqueous solutions. In addition, adsorption kinetic data were nicely described by pseudo-second-order model and the adsorption isotherm data fitted well with the Freundlich equation. Having tailorable physicochemical properties coupled with the ability to uptake dye, these salecan-incorporated hydrogels could be promising platform for wastewater treatment and removal of heavy metal ions.