Synthesis of MnFe2O4/activated Carbon Derived from Durian Shell Waste for Removal of Indole in Water: Optimization, Modelling, and Mechanism

While durian shell is often discharged into landfills, this waste can be a potential and zero-cost raw material to synthesize carbon-based adsorbents with purposes of saving costs and minimizing environmental contamination. Indole (IDO) is one of serious organic pollutants that influence aquatic species and human health; hence, the necessity for IDO removal is worth considering. Here, we synthesized a magnetic composite, denoted as MFOAC, based on activated carbon (AC) derived from durian shell waste incorporated with MnFe 2 O 4 (MFO) to adsorb IDO in water. MFOAC showed a microporous structure, along with a high surface area and pore volume, at 518.9 m 2 /g, and 0.106 cm 3 /g, respectively. Optimization of factors affecting the IDO removal of MFOAC were implemented by Box - Behnken design and response surface methodology. Adsorption kinetics and isotherms suggested a suitable model for MFOAC to remove IDO. MFOAC was recyclable with 3 cycles. Main interactions involving in the IDO adsorption mechanism onto MFOAC were clarified, including pore filling, n- pi interaction, pi- pi interaction, Yoshida H-bonding, H-bonding.