ABSTRACT
In this study, phenol formaldehyde-montmorillonite (PF-MMT) was prepared and used for lead ion (Pb2+) adsorption. Batch adsorption experiments were conducted to determine the optimal conditions. The calculated adsorption equilibrium (q) revealed that pseudo-second-order (PSO) and Langmuir isotherm models best fit the experimental data, suggesting chemisorption as the main mechanism. An adsorption capacity (qmax) of 243.9 mg/g was achieved. Fourier transform infrared (FTIR) analysis showed new peaks in PF-MMT-Pb, indicating metal complexation. Scanning electron microscopy (SEM) imaging displayed distinct Pb2+ clusters on the adsorbent surface. Adsorption was rapid, attaining equilibrium within 90 min. Effects of time, dose, concentration, and pH were systematically investigated to optimize the process. Lead ion removal efficiency reached 98.33% under optimum conditions after 90 min. The adsorption process was chemisorption based on the Dubinin-Kaganer-Radushkevich model with a free energy of 14,850 J/mol. The substantial adsorption capacity, rapid kinetics, and high removal efficiency highlight PF-MMT's potential for effective Pb2+ removal from aqueous solution.
ABSTRACT
In this study, we report the successful synthesis of a phenol-formaldehyde-pyrazole (PF-PYZ) compound through the surface functionalization of phenol-formaldehyde (PF) with pyrazole (PYZ). The resulting mixture was subjected to comprehensive characterization using a range of analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The newly synthesized PF-PYZ material effectively removes Cr(VI) ions. Notably, a substantial elimination efficiency of 96% was achieved after just 60 min of contact time. The strategic incorporation of pyrazole (PYZ) as the principal functionalizing agent contributed to this exceptional performance. Notably, the functionalized PYZ sites were strategically positioned on the surface of PF, rendering them readily accessible to metal ions. Through rigorous testing, the optimal sorption capacity of PF-PYZ for Cr(VI) ions was quantified at 0.872 mmol Cr(VI)/g, highlighting the material's superior adsorption capabilities. The practical utility of PF-PYZ was further established through a reusability test, which demonstrated that the chromate capacity remained remarkably stable at 0.724 mequiv Cr(VI)/g over 20 consecutive cycles. This resilience underscores the robustness of the resin, indicating its potential for repeated regeneration and reuse without a significant capacity loss. Our work presents a novel approach to functionalizing phenol-formaldehyde with pyrazole, creating PF-PYZ, a highly efficient material for removing Cr(VI) ions. The compound's facile synthesis, exceptional removal performance, and excellent reusability collectively underscore its promising potential for various water treatments, especially oil field and environmental remediation applications.