Efficiency of alginate-encapsulated biochar/maghemite composite for the adsorptive removal of 3-monochloropropane-1,2-diol from palm oil

The contamination of refined palm oil with 3-monochloropropane-1,2-diol (3-MCPD) has emerged as a critical concern due to its potential carcinogenic effects. In this study, a novel alginate-encapsulated biochar/maghemite composite (Alg-BC/γ-Fe₂O₃) was synthesized as an adsorbent for the efficient removal of 3-MCPD from palm oil. The adsorption study was conducted using a batch method, and the results showed that Alg-BC/γ-Fe₂O₃ exhibited fast adsorption kinetics and high removal efficiency. Under the optimal condition, the developed adsorbent achieved a maximum removal efficiency of 97.4%, significantly outperforming conventional carbon-based adsorbents. Kinetic studies of the adsorption process adhered to a pseudo-second-order model (R² = 0.9989) with the k value at 5.95 × 10⁻¹ g mg⁻¹. min⁻¹. The removal mechanism is driven by hybrid mechanism dominated by physisorption, including hydrogen bonding, electrostatic interactions, and pore-filling, with a minor contribution from metal ligand interaction associated with γ-Fe₂O₃. The findings of this study affirm the potential of the Alg-BC/γ-Fe₂O₃ composite as a highly efficient magnetic adsorbent for the removal of 3-MCPD from refined palm oil.