Potential of hypercrosslinked microporous polymer based on carbazole networks for Pb(II) ions removal from aqueous solutions

In this research, porous adsorbents of hypercrosslinked microporous polymer based on carbazole networks (HCP-CN) were synthesized for Pb(II) elimination from wastewaters. The results demonstrated that the extreme HCP-CN adsorbents utilization in wastewater treatment could remove more than 99.88% of Pb (II) ions. Furthermore, the two consumed adsorbents similarly indicated rapid adsorption kinetics, and it merely took a while to achieve adsorption equilibrium. These characteristics showed that HCP-CN adsorbent was an outstanding candidate for Pb(II) elimination from wastewater. Besides, the thermodynamic characteristics involving Gibbs free energy change ( increment G(0)), entropy change ( increment S-0), and enthalpy change ( increment H-0) of the adsorption procedure were evaluated, and the results affirmed that the adsorption process was exothermic and spontaneous. In addition, response surface methodology (RSM) as a statistical investigation was used to optimize adsorption factors to obtain maximum adsorption capacity and investigate the interactive effect of parameters using central composite design (CCD). Optimum conditions obtained by RSM for maximum adsorption capacity of 26.02 mg/g are 35 degrees C, 40 mg/L, 11, 60 min, and 99.88 for temperature, initial concentration, pH, time, and removal percent, respectively. In the kinetic modeling study, the second-order model was selected as the best model. The values R-2 at temperatures 35 degrees C, 40 degrees C, and 55 degrees C are 0.997, 0.9997, and 0.998, respectively. In the isotherm modeling, Hill model with a value R-2 of 0.9766 has a superior precision compared to the other isotherm models. Also, the values of Delta H and Delta S at Pb(II) concentration of 60 mg/L are 122.622 kJ/mol and 0.463 kJ/mole K, respectively.

Automated summary

The HCP-CN adsorbent showed excellent efficiency and speed in removing lead ions from wastewater, with characteristics of exothermic and spontaneous adsorption process.