Recyclable carbon nanotube/silicone oil emulsion with NaOH aqueous solution for indoor CO2 capture

초록

Emulsion solvents (ES), which are liquid absorbent-based CO<INF>2</INF> capture materials, are developed as simple and expandable droplets to control CO<INF>2</INF> capture performance. An aqueous NaOH solution, which is a chemical absorbent, is encapsulated by functionalized carbon nanotubes (CNTs) to form a solid adsorbent by enhancing the high lipophilicity and high-viscosity silicone oil. The ratio of each component controls the CO<INF>2</INF> capture performance of the solvent. It is shown that droplets of NaOH aqueous solution formed in fine sizes improve the efficiency of the chemical reaction capacity of NaOH and CO<INF>2</INF>, and thus, even when crystallization occurs, they can be used in a stationary environment, and NaOH can be used at a high concentration. It is found that the optimum concentration of CNTs required to minimize the size of the emulsion is 0.075 wt%, while the CO<INF>2</INF> capture capacity is 2.23 mmol<INF>CO<INF>2</INF></INF> g<SUP>-1</SUP><INF>ES-NaOH</INF> at a pure CO<INF>2</INF> concentration and 1.31 mmol<INF>CO<INF>2</INF></INF> g<SUP>-1</SUP><INF>ES-NaOH</INF> at a low CO<INF>2</INF> concentration (2000 ppm, 50% relative humidity). The oil phase can be recycled continuously by separating the crystallized aqueous phase after the CO<INF>2</INF> capture. These results demonstrate that chemical absorbents with excellent CO<INF>2</INF> capture performance can be used safely and for a long time in order to reduce indoor CO<INF>2</INF>, and the CO<INF>2</INF> capture performance can be flexibly controlled.

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