A New Method for Treating Waste Gases Containing NO_x with Low Concentration Based on Rare Earth Metal Complex

摘要

A novel method for removing exhaust gas of NO_x with low concentration based on rare earth metal complex was proposed in this paper. The absorptivities of NO, by different solvents and complexes between yttrium and substituted salicylate under different conditions were investigated. The results showed that the esters e.g., ethyl acetate and butyl acetate have higher absorptivity than that of ketone, water or alcohol and the better volume ratio of solvents to NO, is 1 to 0.9. When added yttrium perchlorate and methyl salicylate to butyl acetate. the absorptivity increases because of coordinated catalytic absorption. The better molar ratio of yttrium perchlorate to methyl salicylate is 1 to 1 and the better amount ratio of yttrium perchlorate to NO, is over 3 to 1. When the absorption liquid of NO, with butyl acetate added yttrium perchlorate and methyl salicylate extracted by water, methyl salicylate is in organic phase can be used to absorb NO, again and yttrium perchlorate with NO_x is in aqueous phase can be used as nitrating agent. The method is economic and effective because not only almost 100 % NO, are removed, but also nitration products are formed. A technological process for the absorption recovery of NO, with low concentration from waste gas is proposed.