THE USE OF CHITIN IN THE MOULTS AND EXOSKELETONS OF MEALWORMS (TENEBRIO MOLITOR) TO REMOVE CATIONIC DYES FROM AQUEOUS SOLUTIONS

Abstract

We analysed the feasibility of using unmodified chitin exoskeletons and moults of mealworms (Tenebrio molitor) as adsorbents to remove cationic dyes – Basic Violet 10 (BV10) and Basic Red 46 (BR46) – from aqueous solutions. We evaluated the characteristics of the adsorption materials using Fourier-transform infrared spectroscopy and determining the pH of the point of zero charge (pHPZC); the pH effect on dye adsorption effectiveness; dye adsorption kinetics (pseudo–first order, pseudo–second order, and intramolecular diffus ion models); and the maximum adsorption capacity of the adsorbents (Langmuir 1 and 2 and Freundlich isotherms). BV10 adsorption on the tested adsorbents was the highest at pH 3, while adsorption of BR46 was highest at pH 6. The adsorption equilibrium time depended mainly on the dye type and its initial concentration; it was 150–210 min for BV10 and 120–150 min for BR46. The maximum adsorption capacity of mealworm exoskeletons reached 5.56 mg/g for BV10 and 31.53 mg/g for BR46, whereas mealworm moults exhibited a higher maximum adsorption capacity, reaching 6.44 mg/g for BV10 and 5.56 mg/g for BR46.