Effect of particle sizes on the kinetics of demineralization of snail shell for chitin synthesis using acetic acid.

This study considers the kinetics of snail shells demineralization process using acetic acid. It was washed, sundried then ground into four different particle sizes. The ranges of particle sizes are 6.3-4.75 mm, 4.75-2 mm, 2 - 1 mm, and 600 -300 μm. The shells were first deproteinized with sodium hydroxide solution thereafter they were demineralized using 1.2 M acetic acid solution. Kinetics of demineralization of the snail shells was performed by XRF analysis of the chitin produced at 5, 10, 15, 20, 25, 30, and 35 min. The kinetic results show that mechanism of chitin formation from snail shell occurs through the chemical reaction controlled (CRC) model of the shrinking core model for particle sizes between 6.3 - 4.75 mm, 4.75-2 mm, and 2-1 mm particle sizes while Fluid Film Diffusion (FFD) model was observed for the smaller range of 600-300 μm particle sizes. The surface morphology and the FTIR analysis of the synthesized chitin were typical of those obtained for earlier studies.