Characterization of chitin synthesized from snail shell

Abstract

Thermogravimetric analysis was used to analyze chitin thermal stability present in unprocessed and processed snail shell samples using different concentrations of HCl and NaOH. The result shows that 42% of CaCO3 in the snail shell decomposes between 699–779 °C while decomposition of chitin (2.11%) starts at 275 °C and ends at 335 °C. De-mineralization and de-proteinization of the snail shell using 1.5 M HCl and 0.4 M NaOH eliminates CaCO3 formation and sample shows existence of 60% chitin decomposing between 346 and 412 °C. The XRD of virgin snail shell showing the main diffraction face intensity for CaCO3 occurring at 2θ = 29.5o with other CaCO3 peaks occur at 2θ = 30.2o, 39.3o, 41.0o, 44.2o, 45.9o, 48.9o, 51.5o, 53.1o and 55.6o. Chitin present occurs at reflection 2θ = 36.3o with weak intensity and the XRD shows no evidence of CaCO3 but two chitin crystalline peaks at 20.6o and 26.3o with 78% lowest crystallinity index.