Functional Modification Of Filter Media

As a high-efficiency dust collector,bag filter can collect dust with high specific resistance and difficult to collect by electrostatic precipitator,especially for fine dust with high removal efficiency,and can cooperate to remove various pollutants such as heavy metal mercury,etc.It is widely used in flue gas dust removal of anthracite coal power plant boilers,circulating fluidized bed boilers and dry desulfurization devices,and is suitable for areas with strict emission requirements.Polyphenylene sulfide(PPS)filter materials have become the material of choice for industrial coal-fired boiler bag dust collectors because of their excellent high temperature resistance,acid and alkali resistance,and flame retardancy.If the PPS filter dust removal technology and exhaust gas denitration technology are combined,the PPS filter material has a denitrification function,which not only simplifies the purification process of industrial exhaust gas,but also saves the floor space.Commercial denitrification catalysts are usually applied in the high temperature range of 300?400?.The use temperature of PPS filter materials is generally lower than 180?.To match the use temperature of PPS filter materials,it is necessary to use catalysts with excellent deNOx performance below 180?.The focus of this article is to find new ways to combine the PPS filter with the catalyst.Manganese-based catalysts exhibit excellent denitrification activity at<200 ? and are widely used in low-temperature NH3-SCR technology.In this paper,three different treatment methods were used to load the manganese-based catalyst on the PPS filter media so as to achieve the purpose of combining the manganese-based catalyst and the PPS filter media.The surface of the PPS filter material was treated with nitric acid,and a series of MnO2/PPS composite denitrification filter materials were prepared by dropping red potassium permanganate and performing an oxidation-reduction reaction.The denitrification activity test results show that the denitrification performance of the composite filter material obtained is better,and when the mass ratio of KMnO4/PPS is 1.0,the composite denitrification filter material exhibits the best denitrification activity,and the denitration rate can reach 100%at 140?.Further characterization shows that manganese dioxide is mainly dispersed on the surface of PPS fibers in a nanostructure.A series of manganese dioxide/poly-o-phenylenediamine coated PPS composite denitration filter materials were prepared by in-situ polymerization.The o-phenylenediamine monomer was evenly dispersed on the surface of the PPS filter material.Potassium permanganate was added dropwise to oxidize and polymerize o-phenylenediamine in an acidic environment,and a polymer coating layer was formed on the surface of the PPS filter material to generate the dioxide.The results show that the denitrification activity is best when the mass ratio of KMnO4/PPS is 1.0,and the denitration rate can reach 94.2%at 180?.FESEM shows that manganese dioxide/poly-o-phenylenediamine is evenly coated on the surface of the PPS filter fibers.A series of MnO2-Fe2O3/PPS composite denitration filter materials were prepared by redox method.The surface of the PPS filter material was treated with sodium dodecylbenzene sulphonate,so that the PPS filter material uniformly adsorbed iron ions in the ferric nitrate solution,and then dropleted potassium permanganate undergoes redox reactions,a PPS filter loaded with MnO2-Fe2O3 catalyst was formed.The test results show that the denitrification activity is best when the mass ratio of KMnO4/PPS is 1.0,and the denitration rate can reach 99.2%at 180?.