Surface modification of α-chitin using an acidic treatment followed by ultrasonication: Measurements of their sorption properties

The biopolymer α-chitin is a promising raw source that can be used as a low-cost material for environmental applications. Nevertheless, its low surface properties and high crystallinity limit its use. Recent developments include surface modification as one of the most promising strategies for the application of α-chitin. To this end, we used an acidic treatment, followed by ultrasonication, to modify the α-chitin surface and improve its sorption characteristics to achieve the above goal. Structural analysis and measurement of the physicochemical properties (chemical structure and thermal degradation) of α-chitin, before and after surface modification, indicated no significant changes. However, specific surface area, morphology, surface charge, crystallinity and study of the sorption of methylene blue (MB) from aqueous solution demonstrated surface modification. It was established that the S_BET of modified α-chitin increased to 110.7 m²/g and the crystallinity index decreased to 48%. Interestingly, the modified α-chitin could easily adsorb organic dye from an aqueous solution. The experimental adsorption capacity of the resulting α-chitin after surface modification reached the value of about 95 mg/g.