Alkali activated cedar wood as an efficient adsorbent for Pb2+ removal from aqueous solutions: Optimization, kinetic, and thermodynamic study

In the present study, the activated carbon prepared from cedar wood was synthesized via NaOH activation and optimized to be used as the adsorbent for Pb2+ removal from aqueous solutions in a batch process mode. The physicochemical properties of the synthesized adsorbent were examined by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analysis. In order to determine the optimum operational conditions, the effects of different parameters including pH, adsorbent dosage, contact time, temperature, and initial Pb2+ concentration on the adsorptive performance of synthesized samples were also investigated. According to the obtained results, the highest Pb2+ ion adsorption capacity (971.9 mg/g) took place in the optimum operational condition of pH = 4, adsorbent dosage of 0.025 g/L, contact time of 60 minutes, 300 ppm of Pb2+, and 30 degrees C. The results showed that among Langmuir, Freundlich, and Temkin isotherms, the obtained data fitted the best with the Freundlich model. Additionally, the process of Pb2+ adsorption was consistent with the pseudo-second order kinetics model, indicating that the rate-determining step is the surface adsorption that involves chemisorption. Finally, according to the calculated thermodynamic parameters, i.e., Delta H degrees, Delta S degrees & Delta G degrees, Pb2+ adsorption on activated cedar wood can be considered as an exothermic and spontaneous process. (C) 2022 Sharif University of Technology. All rights reserved.

Automated summary

In this study, activated carbon derived from cedar wood was synthesized and optimized for the removal of Pb2+ ions from aqueous solutions. The adsorbent exhibited high adsorption capacity under the optimum conditions. The kinetics and thermodynamics of Pb2+ adsorption indicated that it was a spontaneous and exothermic process.