| 摘要 |
<p>PURPOSE:To reactivate poisoned catalyst simply in a short time as well as enhance catalytic activity of unused catalyst by exposure of metal oxide catalysts-carrying porous support to supersonic wave in water or a diluted inorganic acid aequeous solution. CONSTITUTION:A catalyst consisting of a metal oxide supported by a porous support, e.g., silica, alumina, titania, etc., particularly the catalyst for the catalytic reduction of NOx present in gases, is exposed, prior to use or after being deactivated by use, to supersonic wave for a short time in water or a 0.03 to 1.3 wt% inorganic acid aqueous solution, washed with water, and then dried in order to increase or reactivate the catalytic activity of the catalyst. The preferred frequency of the supersonic wave irradiated is approx. 15 to 40 kHz, and also the preferred output of the oscillator is more than 0.35 W/cm<2>. And, the application of a greater amplitude of supersonic wave is more effective. When the catalyst exposed to supersonic wave is washed with water sufficiently, dried at 100 to 150 deg.C, for example, for approx. 1 hour, treated by heating at approx. 400 to 650 deg.C, and lastly baked for 30-180 min. much higher reactivation effect can be attained.</p> |
