Preparation and characterization of activated carbons from Lemon Pulp for oxytetracycline removal

This study aims to remove oxytetracycline (OTC) that harms the ecosystem, with activated carbon (LPAC) obtained from Lemon Pulp (LP). Characterization and properties of LPAC were analyzed by Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD) and point of zero charge (pH_PZC) analyses. BET surface area, pore volume and pH_PZC of LPAC produced by carbonization at 400 °C and activation with KOH at 800 °C were obtained as 1333.01 m²/g, 0.391 cm³/g, and 6.81, respectively. pH, reaction time, initial OTC concentration, and adsorbent amounts were optimized in the adsorption study performed with LPAC with high porosity and micropores. Kinetic evaluation was made with pseudo-first-order, pseudo-second-order, and intra-particle diffusion models and Freundlich, Langmuir, and Temkin equations are used to investigate their isotherms under reaction equilibrium conditions, and also the results were analyzed by statistical method (ANOVA). In pseudo-second-order kinetic and Freundlich isotherm models, where the best results were obtained, R² values were calculated as 0.999 and 0.995, respectively. Maximum OTC removal efficiency was found as 104.22 mg/g. Overall, this research indicates that LPAC for the treatment of water contaminated with antibiotics is environmentally friendly green material.