Adsorption of tetracycline fom wastewater by using Pistachio shell coated with ZnO nanoparticles: Equilibrium, kinetic and isotherm studies

This study investigated the efficiency of the Pistachio shell coated with ZnO nanoparticles (CPS) for Tetracycline (TEC) sequestration from wastewater. Characterization of CPS were investigated using SEM, XRD and FTIR. The removal efficiency conducted and optimized, depended on various parameters such as: (pH, CPS dosage, particle size, shaking speed and initial TEC concentration). An isotherm model reading revealed that the results of the experimental work were a good fit with the Freundlich model. A maximum adsorption capacity (95.06 mg g−1) was achieved at the best conditions (pH = 4, dose = 0.08 g mL−1, particle size = 87 µm, shaking speed = 150 rpm, 25 °C) at 70 ppm initial concentration. Pseudo second order model best fit the kinetics of TEC adsorption onto CPS with high coefficient of determination and more closely experimental uptake and the intraparticle diffusion is not the dominant mechanism. Thermodynamic parameters (ΔH°, ΔS° and ΔG°) showed that TEC adsorption onto CPS was exothermic and spontaneous in nature. The results proved that CPS exhibits an excellent adsorbent for TEC removal from aqueous solution.