TY - JOUR
T1 - The Gas-Absorption/Chemical-Reaction Method for Measuring Air-Water Interfacial Area in Natural Porous Media
AU - Lyu, Ying
AU - Brusseau, Mark L.
AU - El Ouni, Asma
AU - Araujo, Juliana B.
AU - Su, Xiaosi
N1 - Funding Information:
This research was supported by the NIEHS Superfund Research Program (P42 ES04940). The first author was supported by a scholarship from the China Scholarship Council during their stay at the University of Arizona. We thank Matt Narter for his assistance. The authors state no conflicts of interest related to this work. All data used to support this work are reported in the manuscript in the respective tables and figures. The authors thank the editor and reviewers for their constructive comments.
Publisher Copyright:
© 2017. American Geophysical Union. All Rights Reserved.
PY - 2017/11
Y1 - 2017/11
N2 - The gas-absorption/chemical-reaction (GACR) method used in chemical engineering to quantify gas-liquid interfacial area in reactor systems is adapted for the first time to measure the effective air-water interfacial area of natural porous media. Experiments were conducted with the GACR method, and two standard methods (X-ray microtomographic imaging and interfacial partitioning tracer tests) for comparison, using model glass beads and a natural sand. The results of a series of experiments conducted under identical conditions demonstrated that the GACR method exhibited excellent repeatability for measurement of interfacial area (Aia). Coefficients of variation for Aia were 3.5% for the glass beads and 11% for the sand. Extrapolated maximum interfacial areas (Am) obtained with the GACR method were statistically identical to independent measures of the specific solid surface areas of the media. For example, the Am for the glass beads is 29 (±1) cm−1, compared to 32 (±3), 30 (±2), and 31 (±2) cm−1 determined from geometric calculation, N2/BET measurement, and microtomographic measurement, respectively. This indicates that the method produced accurate measures of interfacial area. Interfacial areas determined with the GACR method were similar to those obtained with the standard methods. For example, Aias of 47 and 44 cm−1 were measured with the GACR and XMT methods, respectively, for the sand at a water saturation of 0.57. The results of the study indicate that the GACR method is a viable alternative for measuring air-water interfacial areas. The method is relatively quick, inexpensive, and requires no specialized instrumentation compared to the standard methods.
AB - The gas-absorption/chemical-reaction (GACR) method used in chemical engineering to quantify gas-liquid interfacial area in reactor systems is adapted for the first time to measure the effective air-water interfacial area of natural porous media. Experiments were conducted with the GACR method, and two standard methods (X-ray microtomographic imaging and interfacial partitioning tracer tests) for comparison, using model glass beads and a natural sand. The results of a series of experiments conducted under identical conditions demonstrated that the GACR method exhibited excellent repeatability for measurement of interfacial area (Aia). Coefficients of variation for Aia were 3.5% for the glass beads and 11% for the sand. Extrapolated maximum interfacial areas (Am) obtained with the GACR method were statistically identical to independent measures of the specific solid surface areas of the media. For example, the Am for the glass beads is 29 (±1) cm−1, compared to 32 (±3), 30 (±2), and 31 (±2) cm−1 determined from geometric calculation, N2/BET measurement, and microtomographic measurement, respectively. This indicates that the method produced accurate measures of interfacial area. Interfacial areas determined with the GACR method were similar to those obtained with the standard methods. For example, Aias of 47 and 44 cm−1 were measured with the GACR and XMT methods, respectively, for the sand at a water saturation of 0.57. The results of the study indicate that the GACR method is a viable alternative for measuring air-water interfacial areas. The method is relatively quick, inexpensive, and requires no specialized instrumentation compared to the standard methods.
KW - fluid-fluid interface
KW - gas absorption
KW - interfacial area
UR - http://www.scopus.com/inward/record.url?scp=85034786028&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85034786028&partnerID=8YFLogxK
U2 - 10.1002/2017WR021717
DO - 10.1002/2017WR021717
M3 - Article
AN - SCOPUS:85034786028
SN - 0043-1397
VL - 53
SP - 9519
EP - 9527
JO - Water Resources Research
JF - Water Resources Research
IS - 11
ER -