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

Benzene, toluene, and m-xylenes are among the pollutants in the environment that may harm human health. These fugitive volatile organic compound (VOC) emissions from refineries and petrochemical industries are perennial, although at low concentrations in ppm levels. On similar grounds, the separation of benzene, toluene, and m-xylene compounds (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. In this connection, a new hybrid material was synthesized using a precursor (metal-organic framework (MOF)) and silica aerogels (SA). The precursor (ZIF-8) proportion was varied to understand its effect on the structural and adsorption characteristics. Various advanced analytical characterizations were performed to understand the physicochemical characteristics of the synthesized material. Additionally, 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% were found to have better adsorption capacity than the virgin ZIF-8 and silica aerogel adsorbents. The maximum adsorption capacity near the 90% saturation vapor pressure corresponds to 337 mg/g, 227 mg/g, and 263 mg/g at 25 °C for BTX, respectively.