Adsorption kinetics and thermodynamics of Fe3O4-nanoparticle-based detoxification of process inhibitors in pretreated waste potato peel hydrolysate

Abstract

This study evaluates the efficiency of Fe₃O₄ nanoparticle adsorbent based on contact time, pH, temperature, inhibitors' initial concentration and nanoadsorbent dosage in the removal of inhibitory compounds (ICs) in pretreated waste potato peel hydrolysate using batch adsorption studies. The results revealed chemisorptive interaction between the nanoadsorbent and the ICs. The adsorption of phenol and HMF closely followed the Langmuir model (R² = 0.997 and 0.966, respectively). Meanwhile, acetic acid and formaldehyde adsorption followed the Freundlich model (R² = 0.985 and 0.980, respectively), whereas furfural followed the Temkin model (R² = 0.970). Moreover, the ΔG⁰ (the thermodynamics) decreased with increasing temperature, implying that the nature of the adsorption process is spontaneous (shown by ΔS⁰) and endothermic (indicated by ΔH⁰), except for furfural inhibitor. Fe₃O₄-nano-based adsorbent demonstrates a multi-adsorption mechanism capable of both uniform and variable binding, primarily relying on strong interactions with adsorbate molecules, which is consistent with chemisorptive mechanisms.