Nitrate Reduction

Abstract
Nitrates reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce carbon dioxide and nitrogen which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

Application(s)

It has been discovered that nitrates, including both those occurring in industrial, mining or agricultural waste streams and those in solid nitrate-containing materials, can be reduced to more environmentally benign substances by reacting the nitrates with certain metals in an aqueous solution, then reacting the resulting solution with an amide. A catalyst can be used. The metal salts which form in the reaction can be recovered using an electrochemical process.The method of this invention can be used for denitrification of waste streams having a great variety of components and for treatment of waste streams having a wide range of concentrations of nitrates. For example, the method of this invention can be used for treatment of radioactive waste water effluents which are high in nitrate concentration or for remediation of contaminated natural waters with low levels of nitrates. * processing nitrate streams from nuclear, industrial (e.g., fertilizer manufacturing), mining and farming operations and in environmental restoration projects. * upgrading the capabilities of existing wastewater treatment plants.

Advantages

The electrochemical treatment of the aqueous solution can be done in the same vessel as the nitrogen release reaction or can be done in a separate vessel to which the aqueous solution has been pumped.
The metal recovery may be carried out simultaneously with the nitrite to nitrogen reduction reaction, or simultaneously with the nitrate to nitrite reduction reaction after a reduction step is completed, or the metal recovery may be performed sequentially as a final step of the process.
The recovered metal can be reused in the same on-going process or collected and transported to other uses. Preferably the metal would be reused in the same process.
The process can be carried out in two or three sequential steps or in a one step batch process or in a continuous one step process.

IP Status: Available for Non-Exclusive Licensing

Commercialization Strategy: Foreign rights available

Reference Number: 253

S Number: DOE reference no.(s): 87,257

Patents & Applications:
Belgium Patent Cooperation Treaty Patent Number 0989958 Issued on 07/17/2003 European Patent Convention Patent Cooperation Treaty Patent Number 0989958 Issued on 07/16/2003 Germany Patent Cooperation Treaty Patent Number 69816450.4-08 Issued on 07/16/2003 United States National Patent Number 6030520 Issued on 02/29/2000

Posted: 12-20-2004

Contact
John Mott
Technology Transfer Division
Los Alamos National Laboratory
P.O. Box 1663, MailStop C334
(505) 665-0883
jmott@lanl.gov

Licensing, TT

CONTACTS

Nitrate Reduction