Gas-tight pH measurements to assess an effect of CO2 on groundwater

Saeko Mito, Ziqiu Xue, Bracken T. Wimmer, Abbas Iranmanesh, Hongbo Shao, Randall A. Locke, Sallie E. Greenberg

Research output: Contribution to conferencePaperpeer-review

Abstract

Acidification of water by dissolving CO2 may trigger the release of trace metals from rocks. Thus, pH monitoring is considered to be a key to assess effects of CO2 on groundwater. In this study, we examined a methodology to measure pH of deep-fluid samples using a gas-tight technique. We used a Kuster Flow Through Sampler connected to a custom spectrophotometric pH measurement system at the Illinois Basin – Decatur Project (IBDP) site. The fluid pressure was up to 19 MPa. The Kuster sampler is gas-tight, but cannot maintain pressure at the sampling depth when it is retrieved. In addition, the mechanisms used to transfer fluid from the sampler, called transfer heads, add up to 60 mL of dead space to the 1L sample chamber. To minimize effects of the sampler design on pH measurements, inert gasses (N2 and Ar) were used to purge the transfer heads and maintain pressure in the sampler during sample handling at the surface. Our results suggest that gas-tight pH measurement is especially important when the partial pressure of gas is more than the atmospheric condition.

Original languageEnglish (US)
StatePublished - 2018
Event14th International Conference on Greenhouse Gas Control Technologies, GHGT 2018 - Melbourne, Australia
Duration: Oct 21 2018Oct 25 2018

Conference

Conference14th International Conference on Greenhouse Gas Control Technologies, GHGT 2018
Country/TerritoryAustralia
CityMelbourne
Period10/21/1810/25/18

Keywords

  • colorimetric pH
  • gas-tight technique
  • geochemical monitoring
  • leakage

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Management, Monitoring, Policy and Law
  • Pollution
  • General Energy

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