The Efficiency of Bimodal Silica as a Carbon Dioxide Adsorbent for Natural Gas Treatment

Natural gas (NG) production in Brazil has shown a significant increase in recent years. Oil and natural gas exploration and refining activities indicate circa 86% carbon dioxide content in NG, representing a serious problem for environmental issues related to greenhouse gas emissions and increases in global warming. New technologies using CO2 capture materials have been shown to be more efficient than conventional processes. In this work, a bimodal meso–macroporous silica adsorbent for CO2 adsorption in NG was synthesized and evaluated as a promising material for use in natural gas treatment systems, as silica has specific textural properties that facilitate the capture and storage of this gas. The adsorbent was obtained from silica via the hydrothermal method with n-dodecane emulsion and characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and the BET specific surface area. Adsorption capacity tests were performed for CO2, methane, and their mixtures by the gravimetric method, demonstrating that the adsorbent was selective for CO2 and obtained a good adsorption capacity. The experimental values obtained were compared and adjusted to the models of Langmuir and Freundlich. Thus, the bimodal silica adsorbent developed in this research proved to be excellent for CO2 adsorption and is a promising material for the treatment of NG.