Adsorption of Lead from Aqueous Solution Using Nanostructured Silica Aerogel / Zeolite ZSM-5 Composite

In this study, three composite adsorbents with different percentages zeolite ZSM-5 and silica aerogel, were synthesized. The adsorbents were characterized by FESEM, XRD, FTIR, BET-BJH, and zeta potential. By comparing the performance of the zeolite ZSM-5 (25)/silica aerogel (75) adsorbent as an optimal adsorbent and other inexpensive adsorbents, it was observed that the adsorbent studied in this experiment has good adsorption efficiency. The saturated adsorption capacity reached 476.2 mg/g for Pb+2. To obtain the best isotherm and kinetic model, error functions and regression coefficients, especially the Chi-square test (χ2) and sum square error (SSE), were used. The findings fit well with Temkin isotherm models, according to the adsorption isotherm investigations. The kinetic data for the pseudo-second-order kinetic model exhibited a high correlation coefficient and a low error function. The activation energies for lead were and 11.31 kJ/mol, respectively. These values indicate that physical adsorption has occurred. The Com3 absorbent was separated from the wastewater and reused after recovery. This feature caused the adsorbent to have a strong adsorption ability, so the adsorption process was performed in five cycles. FTIR and EDX analyses were performed to confirm the adsorption of heavy metals by the adsorbent. The results show that the zeolite ZSM-5/silica aerogel composite is a suitable adsorbent for the removal of various toxins(such as heavy metals) in aqueous systems that contain an adsorbate. As a result, the new zeolite ZSM-5/silica aerogel composite may be used on a larger scale as a material to absorb a variety of contaminants.