| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an aqueous urea solution capable of suppressing propagation and decomposition of microorganisms such as mold and fungi during storage and usage fitted as an aqueous urea solution used for SCR denitration for an on-vehicle or installation type apparatus and preventing generation of a harmful ammonia gas and odor, and its production method. <P>SOLUTION: In the production method for the sterilized aqueous urea solution, after carbon dioxide is dissolved in the aqueous urea solution having a urea concentration of 30-50 mass% to adjust a pH value to 7.5 or lower, hydrogen peroxide is added to the aqueous solution. In the obtained aqueous urea solution, pH is maintained to 8.0 or lower under airtight storage at 40°C or lower for one year. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
