Removal of azo dye in water using novel adsorbent based on rice husk biochar with surface modification by protein

https://doi.org/10.62239/jca.2025.069

Abstract

In the present study, rice husk biochar was modified with protein lysozyme to enhance the removal of toxic organic dye, Acid Orange 7 (AO7) in water. Surface modification of rice husk biochar with lysozyme increased the removal efficiency of AO7 significantly compared with bare biochar. The maximum removal of AO7 using lysozyme modified biochar exceeded 97.9% at pH 3. Adsorption isotherms of AO7 were in good agreement with Langmuir model while adsorption kinetics were well fitted by pseudo-second- order model. Under selected conditions, adsorption capacity of AO7 on lysozyme modified biochar reached 24.63 mg/g.  The adsorbent was applicable for regeneration with high efficiency of greater than 80%. The removal efficiencies of AO7 in actual water samples were higher than 75%. Our study highlights the potential of bio-adsorbent based on protein modified for removal of organic dye from water environment.