A new type of chitosan hydrogel sorbent generated by anionic surfactant gelation

A new type of chitosan hydrogel beads (CSB) with a core–shell membrane structure was generated by sodium dodecyl sulfate (SDS) gelation process. CSB exhibited higher mechanical strength and acid stability than chitosan hydrogel beads (CB) formed by alkali gelation. The effect of SDS concentration variation during gelation on the adsorption capacity of CSB for congo red (CR) as a model anionic dye showed that CSB formed by 4 g l−1 SDS gelation had the highest adsorption capacity. The maximum adsorption capacity of CSB (208.3 mg g−1) obtained from the Sips model was found slightly higher than that of CB (200.0 mg g−1). Membrane materials of CSB obtained after squeezing core water from the beads showed approximately 25 times higher volumetric adsorption capacity than CB.