Dynamic adsorption of toluene on amino-functionalized SBA-15 type spherical mesoporous silica

Amino-functionalized spherical mesoporous silica (ASMS) materials were successfully prepared via a convenient treatment method by using 3-aminopropyltrimethoxysilane (APTES), which was used in different concentrations in the process of spherical mesoporous silica (SMS) synthesis. The adsorption performances of ASMS were evaluated by taking toluene as a simulated pollutant and the adsorption mechanism was also studied. A variety of characterization methods were adopted, including scanning electron microscopy, small-angle X-ray diffraction and Fourier-transform infrared spectroscopy techniques and nitrogen adsorption-desorption analyses, which led to a better understanding of the performance of the materials. It was found that the SMS has a good adaptability due to the amino functionality, the pore structure still remains in the modified samples even when the mass ratio of APTES/TEOS is up to 3, and the chemical properties of the material surface are significantly improved by the amino functionality. The results show that the capacities of the toluene adsorption follow the order of SMS < ASMS-1 < ASMS-3 < ASMS-2. ASMS-2 has the highest toluene adsorption capacity (98.1 mg g^-1) and the saturated adsorbent can be easily regenerated by thermal desorption, which has a stable adsorption capacity after 4 adsorption cycles. These experimental data indicated that amino functionalization could affect both the pore structure and surface chemical properties of SMS, making ASMS a promising material for the reduction of industrial volatile organic compound emissions in air treatment.