A Facile Synthesis of Highly Porous Silica Aerogel Hybrid Materials for BTX Adsorption

Benzene, toluene, and m-xylenes (BTX) are among the pollutants in the environment that may harm human health. These fugitive VOC emissions from refineries and petrochemical industries are perennial, although at low concentrations in ppm levels. The separation of BTX from the feed gas of the sulfur recovery unit in natural gas processing industries is critical, as it is known to severely poison the catalyst in the Claus process. To address this, a new hybrid material was synthesized using a precursor (metalorganic framework (MOF)) and silica aerogels (SA). The precursor (ZIF-8) proportion was varied to evaluate its effect on the structural and adsorption characteristics. Various advanced analytical characterizations were conducted to understand the physicochemical characteristics of the synthesized material. The synthesized materials were subjected to gas-phase adsorption of BTX to generate the adsorption isotherm at 25°C. The hybrid material SA-ZIF-8 (20%) having a ZIF-8 proportion of 20% displayed better adsorption capacity than the virgin ZIF-8 and silica aerogel adsorbents. The maximum adsorption capacity near the 90% saturation vapor pressure corresponded to 337 mg/g, 227 mg/g, and 263 mg/g at 25°C for BTX, respectively.