Preparation And Properties Of Nitrogen Oxide Catalyst Derived From Sewage Sludge

The residual sewage sludge produced through biologic method treatment domestic sewage is taken as raw material, based on the disadvantages of all kinds of traditional sewage sludge treatment. The chemical activation method is applied to paralysis sewage sludge to obtain porous carbonaceous catalysts. At first, the production method of the catalysts has two choices. The first method included impregnation, pyrolysis, and the second included pyrolysis, impregnation and calcinations. The active matter laden also has two choices. One is ferric nitrate, the other is copper nitrate. The production method and active matter laden were selected by catalytic activity evaluation and character analysis, and the concerned conditions are worked out during the production. The carbonaceous catalysts laden ferric nitrate produced in the first method were applied to the nitrogen oxide treatment process. The catalytic capability of the catalysts varied according to many factors. This experiment examined some factors included Zn:Fe molar ratio, pyrolysis temperature, reaction temperature and oxygen concentration by orthogonal experiments and single factor experiments. The experiment result showed that the maximal NO_X conversion of 98.3% was obtained under the following condition: Zn:Fe molar ratio of 1:0.5, pyrolysis temperature was 750℃, reaction temperature was 400℃, and oxygen concentration of 15%. After selecting the best production conditions and the best reaction conditions, the experiment further examined the catalytic activity, self-reduction and catalytic life of the catalyst under the optimal conditions. The results exhibited the catalyst still keep favorable catalytic capability, and it had definite reductive capability, the catalytic life can be accepted. Then the characteristic analysis on the catalyst are carried out, include granularity analysis, BET analysis, SEM analysis, FT-IR analysis, X-ray analysis. These analyses indicates the catalyst have predominant conditions. The granularity analysis indicates the catalysts' granules are thin and well-proportioned, and propitious to touch with reaction gas. The BET analysis indicates the catalysts have biggish BET area and maximal area is 307.0 m²Â·g^-1. This characteristic indicates the catalysts have well adsorption capability. The SEM analysis indicates the catalysts have well microcosmic structure, in other words, the hole structure of catalysts is well. In addition, lots of active particles are scattered on the catalysts' surface. The FT-IR analysis indicates lots of oxygenous functions are distributed on the catalysts' surface; these are propitious to improve activation of catalysts. The X-ray analysis indicates catalysts have well crystal structure and abundant oxides. At last, the catalyst's application and foreground are analysised.