A New Functionalized MCM-41 Mesoporous Material for Use in Environmental Applications

This work describes the synthesis and characterization of a new mesoporous adsorbent consisting of MCM-41 functionalized with modified p-aminobenzoic acid (PABA-Si). The synthesis was performed by a hydrothermal/co-condensation method. The PABA-MCM-41 was characterized using FTIR, SAXS, N2 adsorption/desorption, SEM, and TG. Batch experiments were employed to determine the effects of initial adsorbate concentration, contact time, and temperature. The adsorption of benzo[a]pyrene (B[a]P) reached equilibrium after ca. 90 min (q e = 27.2 µg g-1), and higher adsorbate concentrations were associated with increases in both the percentage removal (71.0-95.7%) and the value of q e (20.1-27.1 µg g-1). The adsorption followed pseudo-second order kinetics, and was fitted using the Langmuir isotherm model. At higher temperatures, there were increases in the initial rate of adsorption and the kinetic constant. The thermodynamic parameters indicated that the process was spontaneous, endothermic, and with a tendency to disorder.