Adsorption activity of cerium-magnesium ferrite nanoparticles on woodchip-derived biochar for enhanced organic pollutants removal

Abstract

Herein, ternary Ce-in-MgFe 2 O 4 was incorporated onto woodchip-derived biochar to design a recyclable nanocomposite (Ce-in-MgFe 2 O 4 -WCBC) for TC and MB adsorption from aqueous environments in single and binary systems. The physicochemical characteristics of Ce-in-MgFe 2 O 4 -WCBC were examined. The introduction of ternary oxides enhanced the structural stability and surface potential of Ce-in-MgFe 2 O 4 -WCBC, providing more adsorption sites for TC and MB adsorption, with an increased BET surface area (67 m 2 /g) and pore volume (0.085 cm 3 /g). The Ce-in-MgFe 2 O 4 -WCBC exhibited maximum TC and MB adsorption capacities of 100.9 mg/g for TC and 135.7 mg/g for MB in a single system. The adsorption kinetics and isotherm data of TC and MB were best described by pseudo-second-order and Langmuir models, suggesting that TC and MB were chemically adsorbed. In the presence of co-existing ions, Ce-in-MgFe 2 O 4 -WCBC retained strong selectivity for TC and MB, having adsorption performance of over 68% and 78% of the initial capacities for TC and MB, respectively, after four cycles. The binding mechanism for TC and MB adsorption was pore-filling, electrostatic attraction, hydrogen bonding, metal–ligand complexation, and π–π EDA interactions. The molecular mechanics calculation showed TC and MB adsorption over Ce-in-MgFe 2 O 4 -WCBC was favoured at the edge sites (negative binding energies), indicating synergistic interactions between metal oxides and oxygen-containing functional groups. Hence, a Ce-in-MgFe 2 O 4 -WCBC could be an effective, alternative, reusable, and sustainable adsorbent for the industrial wastewater treatment process. • Woodchips-derived biochar incorporated Ce-in-MgFe 2 O 4 was successfully designed. • Adsorption capacities were 100.9 and 135.7 mg/g for TC and MB, respectively. • π–π electron donor–acceptor interactions contribute to the TC and MB adsorption. • Ce-in-MgFe 2 O 4 -WCBC exhibited excellent reusability even after four reuse cycles. • TC and MB adsorption is favoured at the edge sites through synergistic interactions.