Study on CO₂ Desorption Behavior of a PDMS-SiO₂ Hybrid Membrane Applied in a Novel CO₂ Capture Process

In this present work, a novel approach has been proposed by which a solvent absorption and membrane desorption methods can significantly reduce the carbon dioxide (CO₂) emission and energy consumption. In this method, the CO₂ capture processing is based on the combination of membrane and physical solvent. Here, dimethyl carbonate and polydimethylsiloxane (PDMS)-SiO₂ nanocomposite were used as the physical solvent and desorption membrane, respectively. However, the main focus of this research was on the CO₂ desorption behavior of PDMS-SiO₂ hybrid membrane. To do so, the influence of the operating conditions and membrane properties on the pervaporation process to capture CO₂ have been investigated. The PDMS-SiO₂ hybrid membrane containing 10 wt % SiO₂ was the most effective membrane. Results revealed that increase in CO₂ concentration from 1.5 to 3 wt % led to decrease in the selectivity from 94 to 47 and increase in flux from 1.7 to 5.38 (kg/m²·h). In addition, an increase in temperature increased the flux and reached the highest level (8.17 kg/m²·h) at 40 °C. However, the selectivity decreased to 36.13. It was found that the addition of SiO₂ nanoparticles to the PDMS membrane not only enhanced the membrane performance but also decreased the energy consumption about 75% compared with gas stripping method and mass transfer about 49% compared with pure PDMS membrane. Finally, these results illustrated that such a novel technique used for pervaporation separation process is a green and promising alternative to separate CO₂ from the physical solvent.