Evaluation of Thiol-Functionalized Mesoporous Silica for Lead Removal from Contaminated Water

Lead contamination poses a significant environmental and health risk. To address this challenge, we synthesized a composite material comprising functionalized magnetite KCC-۱ mesoporous silica. This material incorporates iron oxide nanoparticles and thiol groups (-SH) within its porous structure. The synthesized materials were characterized using various techniques, including FTIR, FE-SEM, XRD, BET-BJH, and VSM spectroscopy. Lead adsorption was measured using Flame Atomic Absorption Spectroscopy. The adsorption isotherm data indicated that lead adsorption follows the Freundlich isotherm model, suggesting the presence of heterogeneous adsorption sites on the adsorbent surface. One type likely involves interactions with the thiol groups, while the other involves unmodified silanol groups present on the silica surface. Based on the Langmuir isotherm, the maximum adsorption capacity was determined to be ۲۸۷.۱۴ mg/g. The correlation coefficients (R²) of the Langmuir, Freundlich, and Temkin plots were ۰.۹۹۱, ۰.۹۹۴, and ۰.۹۸۸, respectively. Kinetic studies further revealed that the adsorption process follows a pseudo-second-order rate law. The correlation coefficients (R²) of the pseudo-first-order and pseudo-second-order plots were ۰.۸۲۴ and ۰.۹۷۸, respectively. Thermodynamic studies showed that the Gibbs free energy decreased from -۸۰۲ kJ/mol at ۲۹۳ K to -۱۹۰.۶۳ kJ/mol at ۳۰۸ K, suggesting that increasing the temperature favors lead adsorption.

کلیدواژه ها:

Lead removal ، Functionalized mesoporous silica ، Magnetite nanoparticles ، Thiol groups ، Freundlich Isotherm