Preparation of hemin-bound chitosan flakes and their dye decolorizing ability

Hemin was immobilized on chitosan flakes using the conventional ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide system to produce hemin-bound chitosan (HC) flakes. The HC flakes demonstrated oxidation ability in the presence of H₂O₂, similar to hemin, but with improved photostability and reusability caused by immobilization on chitosan flakes. While the HC flakes did not adsorb cationic dyes such as Methylene blue and Rhodamine B, they effectively adsorbed anionic dyes such as Eosin Y and Congo red, while hemin did not adsorb either of these two dyes. The HC flakes exhibited good decolorization ability of anionic dyes in a system using H₂O₂, proving to be a simple -and economical agent for removing anionic dyes by adsorption and oxidation.