CO₂ Capture Performance on Wall Paint Modified by K₂CO₃ and CA(OH)₂ for Added-Value CO₂ Capture Paint Development

Abstract

“Smart paint” is an application that can adsorb CO₂ contributed by transportation in urban areas. This research investigated the adsorbent and their effect which can enhance the CO₂ adsorption in paint. CO₂ capture was tested after drying coated paint. The apparatus was designed as a layered box under open indoor system for investigating the effect of modified paints. The paints were modified by adding K₂CO₃ or Ca(OH)₂. In order to carry out the experiment, 100 g of modified paint were applied to the board inside the CO₂ adsorption unit while the gas flow rate and moisture were controlled at the ambient temperature.  The results showed that the increase in solid adsorbent loading in the modified paint with K₂CO₃ could raise the adsorption capacity of the paint. However, the adsorption capacity was limited by some properties in the paint, such as glossy. The adsorbent loading influenced the long-term stability of the paint. On the other hand, the modified paint with Ca(OH)₂ could adsorb CO₂ with higher capacity and maintain better long-term stability than that with K₂CO₃. Also, the effect of gas flow rate and humidity showed that the increase in either flow rate or humidity could also enhance CO₂ adsorption capacity. The best case of modified paint with Ca(OH)₂ in this study could adsorb CO₂ at 9.61 mg-CO₂/g-paint, which is equivalent to 4.58 g-CO₂/m^2, while the conventional paint (non-modified paint) could adsorb CO₂ of approximately 0.06 g-CO₂/m². Finally, this study demonstrates that modified paint with K₂CO₃ and Ca(OH)₂ can be a new feature to add value to the paint industry.