Influence of synthesis approach and formulation on the physicochemical properties of chitin and chitosan from Black Soldier Fly

Abstract

In recent years, numerous studies have emerged on the application of biosorbents for dyes removal from wastewater. Chitosan, a derivative of chitin, is particularly effective as a flocculant for this purpose. In this study, purified chitin was subjected to a physicochemical evaluation based on FESEM, FTIR, XRD, and TGA as well as the deacetylation step. The unique characteristics of chitin isolated using NADES enhance its suitability for efficient deacetylation and higher conversion to chitosan compared to chitin isolated with organic solvents. The chitin 1D, isolated using organic solvent, displayed a complex, convex structure, like a honeycomb, whereas chitin isolated using NADES exhibited a more fibrous and irregular structure. The data indicated that chitin extracted from BSF pupae was α-chitin with FTIR spectra matching closely to commercial chitin. Chitin isolated using organic solvent demonstrated higher crystallinity and higher thermal stability than chitin isolated using NADES. The trends of decreasing acetylation and increasing deacetylation obtained in all studied samples were indicators for the successfulness of the deacetylation reaction. The X-ray diffraction profiles verified the presence of α-chitin and the relative crystalline indexes ranged from 80 to 86 %. This study provides a green and facile approach for chitin extraction from BSF pupae using a more sustainable approach as the physicochemical properties obtained for chitin isolated using NADES are comparable with chitin isolated with the organic solvent. Multiple analytical methods employed in this study successfully demonstrated that chitin can be effectively extracted from BSF pupae, with data comparable to those published in the literature and to commercial samples.

Keywords

• Biosorbents
• Chitin
• Chitosan
• Deep Eutectic Solvents (DES)
• Organic solvent