Thermochemical nitrate reduction
A series of preliminary experiments was conducted directed at thermochemically converting nitrate to nitrogen and water. Nitrates are a major constituent of the waste stored in the underground tanks on the Hanford Site, and the characteristics and effects of nitrate compounds on stabilization techniques must be considered before permanent disposal operations begin. For the thermochemical reduction experiments, six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with {approximately}3 wt% NO{sub 3}{sup {minus}} solutions in a buffered aqueous solution at high pH (13); ammonia and formate were also mixed at low pH (4). Reactions were conducted in an aqueous solution in a batch reactor at temperatures of 200{degrees}C to 350{degrees}C and pressures of 600 to 2800 psig. Both gas and liquid samples were analyzed. The specific components analyzed were nitrate, nitrite, nitrous oxide, nitrogen, and ammonia. Results of experimental runs showed the following order of nitrate reduction of the six reducing agents in basic solution: formate > glucose > urea > hydrogen > ammonia {approx} methane. Airnmonia was more effective under acidic conditions than basic conditions. Formate was also effective under acidic conditions. A more thorough, fundamental study appears warranted to provide additional data on the mechanism of nitrate reduction. Furthermore, an expanded data base and engineering feasibility study could be used to evaluate conversion conditions for promising reducing agents in more detail and identify new reducing agents with improved performance characteristics.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 7077253
- Report Number(s):
- PNL-8226; ON: DE92041356
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NITRATES
REDUCTION
RADIOACTIVE WASTE PROCESSING
DENITRATION
AMMONIA
CHEMICAL REACTION KINETICS
CHEMICAL REACTORS
EXPERIMENTAL DATA
FORMATES
GAS CHROMATOGRAPHY
GLUCOSE
HYDROGEN
METHANE
REDUCING AGENTS
TEMPERATURE RANGE 0400-1000 K
THERMOCHEMICAL PROCESSES
UREA
ALDEHYDES
ALKANES
AMIDES
CARBOHYDRATES
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DATA
ELEMENTS
HEXOSES
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
MANAGEMENT
MONOSACCHARIDES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PROCESSING
RADIOACTIVE WASTE MANAGEMENT
REACTION KINETICS
SACCHARIDES
SEPARATION PROCESSES
TEMPERATURE RANGE
WASTE MANAGEMENT
WASTE PROCESSING
052001* - Nuclear Fuels- Waste Processing