Norfloxacin removal from aqueous solution using biochar derived from luffa sponge

This study addresses the absorbance of norfloxacin (NOR) in wastewater by biochar derived from luffa sponge. Observations using scanning electron microscopy (SEM) show that the adsorbent surface is coarse with a heterogeneous, irregular, and highly porous structure. The calculated Brunauer-Emmett-Teller (BET) surface area of the adsorbent is 822.35 m²/g with an average pore size of 5.35 nm. In the experiments, the biochar (BC) adsorbed 99.86% of the NOR with a maximum absorption of approximately 250 mg/g. The correlation coefficient (R² > 0.99) for the Freundlich simulation indicates multimolecular layer adsorption. The pseudo-second-order model (R² = 0.9998) indicates that chemisorption involving valence forces through the exchange or sharing of electrons controls the adsorption rate. A negative enthalpy change confirms endothermic adsorption. Fourier-transform infrared (FTIR) spectroscopy analysis indicates that the BC surface contains more acidic oxygen-containing groups, such as carboxyl, phenol hydroxyl, lactone, and carbonyl. These findings demonstrate that luffa sponge biochar can efficiently remove NOR from aqueous solutions. Additionally, the use of luffa, which is a natural biological material, can help to reduce waste and provide a new source of BC for wastewater treatment of antibiotic residues.