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°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., ΔH°, ΔS° & ΔG°, Pb²⁺ adsorption on activated cedar wood can be considered as an exothermic and spontaneous process. [ABSTRACT FROM AUTHOR]