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Apparatus for Sampling and Controlling Gas Composition in Redox‐Controlled Soil Slurry
Author(s) -
Guenzi W. D.,
Hutchinson G. L.,
Beard W. E.
Publication year - 1989
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1989.03615995005300050053x
Subject(s) - slurry , inert gas , gas composition , volume (thermodynamics) , environmental science , inlet , chemistry , sampling (signal processing) , volumetric flow rate , soil gas , trace gas , mixing (physics) , inert , airflow , soil vapor extraction , soil water , solenoid , contamination , environmental engineering , soil science , filter (signal processing) , environmental remediation , mechanical engineering , physics , organic chemistry , quantum mechanics , computer science , engineering , computer vision , thermodynamics , ecology , biology
Study of the production or consumption in soil of gaseous N compounds at near ambient concentrations requires unique apparatus and procedures. We used a soil slurry that is continuously flushed by a gas stream with controlled composition. Basic components of the system include a reaction chamber equipped to monitor and control slurry pH, E h , and temperature, flow controllers for precise control of gas flow rates, a mixing chamber for blending inlet gases from different sources, a low‐volume manifold for collecting contamination‐free samples of inlet and exit gases, a dryer to selectively remove water vapor from the exit gases, and a large‐volume sample loop for collecting enough sample gas for NO analysis. The E h control was accomplished using automated three‐way solenoid valves to select either O 2 or an equal flow of inert gas to mix with the gas stream flushing the reaction chamber. Although the gas sampling and gas handling apparatus and procedures described here were designed for an E h ‐controlled soil slurry, we believe they could be easily adapted to other experimental systems that require trace gas sampling and control without contamination from ambient air.