Green chitosan extraction from Hermetia illucens breeding waste (prepupal cases): Characterization and bioadsorption activity.

Heavy metal contamination has harmful consequences for the ecosystem. They are naturally non-biodegradable, and can cause severe ecotoxicity and numerous pathologies. Several bioadsorbents have been used for metal pollution control, and chitosan is one of the biomaterials that has proven to be an efficient adsorbent. The aim of the present work is to exploit the rearing waste of Hermetia illucens (prepupal cases), commonly known as the Black Soldier Fly (BSF), to produce chitin and its derivative chitosan by microwave-assisted process, and to study the interaction of this biopolymer with zinc and cadmium. All the samples obtained were characterized by several methods, including FTIR, XRD, TGA/DSC, H NMR, SEM, and viscosimetric studies. The chitosan obtained has interesting physicochemical properties with an acetylation degree (DA) equal to 2.3 %, Molecular weight (M) equal to 155 kDa, and a crystallinity index (I) around 51.26 %. Chitosan was also found to have an adsorption capacity of Cd and Zn around 141.05 mg·g and 45 mg·g respectively by absorption atomic spectroscopy (AAS). Results confirm the effectiveness of chitosan derived from BSF, obtained through an eco-friendly method, as a sustainable and efficient bioadsorbent for addressing heavy metal contamination.