Partial carbonized nanoporous resin for uptake of lead from aqueous solution Available to Purchase

Four partial carbonized nanoporous resins (PCNRs), based on organic xerogel compounds, were synthesised by the sol–gel method from pyrogallol and formaldehyde mixtures in water using picric acid as catalyst. The PCNRs were prepared at different pyrolysis temperatures: T₁ = 200 °C (PF-200), T₂ = 300 °C (PF-300), T₃ = 400 °C (PF-400), or T₄ = 500 °C (PF-500). The PCNRs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy, and nitrogen porosimetry. The obtained results show that PF-200 is more efficient for the removal of Pb²⁺ from aqueous solution than the other adsorbent prepared in this study. The characteristics of lead uptake by PF-200 were explored using well-established and effective parameters including pH, contact time, initial metal ion concentration and temperature. Optimum adsorption of Pb²⁺, using PF-200, was observed at pH 4.5. The Langmuir model gave a better fit than the other models, and kinetic studies revealed that the adsorption was well fitted by the pseudo second-order kinetic model and thermodynamic properties, i.e., Gibbs free energy change, enthalpy change and entropy change, showed that adsorption of Pb²⁺ onto PF-200 was endothermic, spontaneous and feasible in the temperature range of 298–328 K.