Micro gas preconcentrator using metal organic framework embedded metal foam for detection of low-concentration volatile organic compounds

Abstract

Analysis of volatile organic compounds (VOCs) is essential for on-site environmental monitoring and toxic chemicals detection. However, quantitatively detecting VOC gases is difficult because of their low gas concentration (<100 ppb), and preconcentration is necessary to overcome the detection limitations of various gas sensors. Many studies on micro preconcentrators (μ-PC) have been reported, however, these devices suffer from high desorption temperatures and significant pressure drops, which degrade sensing ability and increase operating costs, respectively. Due to these disadvantages, such devices are not yet commercially available. In this study, a μ-PC was developed using metal organic framework embedded metal foam (MOFM) as an adsorbent. The preconcentration performance of the μ-PC was evaluated based on several key parameters, such as desorption temperature, adsorption time, and initial sample concentration. In addition, the MOFM and commercial adsorbents were each packed in the same μ-PC chip, respectively, to compare their preconcentration and pressure drop performances. The MOFM-adsorbent-packed μ-PC demonstrated the preconcentration factors were 2.6 and 4 times higher, and the pressure drops were 4 and 3 times lower than those of the commercial adsorbents under the same conditions owing to the high specific surface area and the efficient flow distribution of the MOFM adsorbent.