Dariush Naghipour - Research Center of Health and Environment, Guilan University of Medical Sciences, Rasht, Iran
Abdoliman Amouei - Social Determinants of Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
Kamran Taher Ghasemi - Department of Environmental Health, Guilan University of Medical Sciences, Rasht, Iran
Kamran Taghavi - Department of Environmental Health, Guilan University of Medical Sciences, Rasht, Iran

Background: Metoprolol (MTP) with its low biodegradability is one of the most dominant micropollutant in the effluent of wastewater treatment plants. The aim of this study was to investigate the removal of metoprolol from aqueous solutions by the activated carbon prepared from pine cones. Methods: The pine cones were activated using thermal activation method. Characteristics of theadsorbent were determined using Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). In this study, the influent of different parameters such as pH, contact time, initial concentrations of metoprolol, adsorbent dose, temperature, adsorption isotherms, and kinetics were investigated. Results: The maximum removal efficiency of MTP (89.2%) was obtained at pH=8.5, adsorbentdose=1.5 g, contact time=60 min, and initial concentration=50 mg/L. By increasing the adsorbent dose, the removal efficiency also increased, but the adsorption capacity decreased, however, by increasing the initial concentration, the removal efficiency decreased, but the adsorption capacity increased. The isotherm experimental data for metoprolol was best fitted using the Langmuir model, and kinetic datawere better described by pseudo-second-order kinetic model. The thermodynamic study indicated that the adsorption of MTP by the adsorbent was feasible, spontaneous, and endothermic. Conclusion: MTP removal by the activated carbon prepared from pine cones showed that this natural adsorbent is appropriate for removal of metoprolol from aqueous solutions regarding cost, efficiency, and production method.

Metoprolol, Adsorption, Pine cones, Isotherm, Kinetics, Thermodynamics