Single-Step Synthesis of Hydrophobic Silica Aerogel Membranes for Membrane Contactors Used for Carbon Dioxide Capture

Single-step synthesis of hydrophobic silica aerogel membranes for membrane contactors used for carbon dioxide capture.

Chia-Chieh Ko,^{[a, b]} Yi-Feng Lin,^[a] Kuo-Lun Tung^*[b]

 ^[a]Department of Chemical Engineering and R&D Center for Membrane Technology,

Chung Yuan Christian University, Chungli 320, Taiwan (R.O.C.).

^[b]Department of Chemical Engineering, National Taiwan University,

Taipei 106, Taiwan (R.O.C.).

^*kuolun@ntu.edu.tw (Kuo-Lun Tung)

Abstract

The application of membrane contactor for CO₂ capture which combined with hydrophobic porous membrane and chemical absorption has attracted considerable attention due to its low operational costs and low energy consumption^{1, 2}. However, the cost of membrane preparation was relatively high³. Therefore, this study attempted to prepare a suitable hydrophobic membrane via a single-step low-cost procedure previously proposed by our group. Herein, methyltrimethoxysilane (MTMS) derivative silica aerogels were choose due to their hydrophobicity and successfully coated on a macroporous Al₂O₃ membrane support as illustrated in Figure 1. Furthermore, the effect of base-catalyst concentration and solvent amount on their performances in a membrane contactor for CO₂ absorption were discussed. Finally, under the optimum synthesis conditions, the MTMS derivative silica aerogel membrane exhibited high and quite stable CO₂ absorption flux under continuous operation for four days. Also, the resulting MTMS derivative silica aerogel membrane could potentially be used during the post-combustion process in power plants since its excellent reusability as shown in Figure 2.

Fig. 1 Diagram for CO2 gas absorption in a membrane contactor using MTMS silica aerogel membranes.	Fig. 2 Three cycles of CO2 absorption flux versus time for the MTMS aerogel membrane.

References

1. S. H. Lin, K. L. Tung, W. J. Chen, H. W. Chang, J. Membr. Sci., 2009, 30, 333.

2. S. H. Lin, K. L. Tung, H. W. Chang, K. R. Lee, Chemosphere, 2009, 75, 1410.

3. Y. F. Lin, C. H. Chen, K. L Tung, T. Y. Wei, S. Y. Lu, and K. S. Chang, ChemSusChem, 2013, 6, 437.