Highly efficient colorimetric CO 2 sensors for monitoring CO 2 leakage from carbon capture and storage sites

• Published in: The Science of the total environment 2020-04, Vol.729, p.138786
• Main Authors: Ko, Kwanyoung, Lee, Ji-Yeon, Chung, Haegeun
• Format: Article
• Language: English
• ISSN: 1879-1026

Carbon capture and storage (CCS) technology used for reducing anthropogenic CO emissions involves the capture of CO from industrial sources and its injection into geological sinks, such as oil reservoirs and abandoned gas fields. To ensure environmental and public safety in implementing CCS technology, efficient CO -monitoring technology must be developed to detect potential CO leakage from CCS sites. Conventional CO sensors used for monitoring CCS sites are typically high in cost and require professional staff for maintenance. In this study, we developed a portable and low-cost colorimetric CO sensor with high soil CO detection efficiency for CCS sites. The sensor consists of a detection solution that contains the pH indicator cresol red encapsulated with a gas-permeable membrane. When CO enters the sensor through the membrane, the color of the pH indicator changes and this was quantified using an RGB (red, green, blue) application (app), an app that measures the RGB values of a given color. The change in G and B values of the detection solution showed a significant linear relationship with soil CO concentration determined via non-dispersive infra-red (NDIR) CO sensor (r  = 0.98, p = 0.001), and thus these values were used for quantification of CO concentration. Tests using CO -injection chamber showed that the optical CO sensors can detect soil CO concentration of 0.1 to 30% within a few minutes. Field studies conducted at a natural CO vent and an artificial CO leakage site showed that the optical CO sensors can be applied in analyzing surficial CO leakage patterns. The advantage of this optical CO sensor when applied to field monitoring is that it is inexpensive and has few installation restrictions. Therefore, this optical CO sensor has a strong potential for use in monitoring CO leakages from CCS sites.