Ultrasound-assisted treatment of chitin: evaluation of physicochemical characteristics and dye removal potential

Abstract

AbstractChitin was ultrasonically treated to improve its dye adsorption characteristics. The effects of ultrasound cycle and amplitude on the chitin Sauter diameter (DSauter), deacetylation degree (DD), crystallinity index (CI) and specific surface area (SBET) were evaluated. The untreated and treated chitin samples were applied to remove Methylene Blue (MB) and Ponceau 4R (P4R) dyes from aqueous solutions. Chitin DSauter decreased from 625 to 250 μm after the ultrasonic treatment. Chitin DD was not influenced by the ultrasound treatment, remaining in the range of 42.3–45.8%. For all ultrasonic conditions, the chitin CI values decreased from 86.3% (untreated chitin) to 70.0%. The specific surface area (SBET) increased from 2.2 to 38.5 m2 g-1. After ultrasonic treatment, the dye removal percentage increased from 53.2 to 74.3% for MB and from 3.3 to 20.2% for P4R, at initial dye concentration of 50 mg l-1. Treated chitin can be used seven times maintaining the same performance. The ultrasound-assisted treatment is an alternative to improve the chitin dye adsorption characteristics.