The Experimental Study Of Vapor Mercury Removal By Modified Activated Carbon Fibers (ACF)

Mercury pollution caused by coal combustion has brought great harm to environment.With strengthening of people's concept in environment protection, mercury pollution is becoming more of a concern. Currently, adsorbent injection has been a focal point of researches on mercury control in flue gases. And besides the activated carbon (AC), there have no adsorbents with high efficiency, low price and wide adaptability. Therefore, it is significant to find high efficient and broad prospect adsorbents.In this paper, 9 kinds of modified ACF samples were obtained by impregnation and their adsoption capacities were determined with vapor mercury adsorption expriments. The interaction between sample modification and adsorption performance was revealed via futher study of surface structure properties and chemical characteries using scanning electron microscopy (SEM) and X-ray photoelectron spectronscopy (XPS). The main works and achievements were as follows:1. Acorrding to SEM micrographs, silver particles were mainly distributed in the edge and at the junction of microporous of ACF surfaces, particle size and amount of active points on ACF increased with higher AgNO3 solution. XPS spectra results suggested that Ag-O-C formed on surface of ACFs during the modification, Ag of coordination bond took a lead to combine with mercury and then improved adsorption performance.2. There were no particle deposits investigated on SEM image of ACF-MnO2, but the results of EDS indicated that a spot of Mn existed; while several particles adhered to ACF-MoO₃. And XPS spectra results indicated that MoO₃ was on surface of ACF-MoO₃.3. It was clear from S2p of XPS, there were three chemical states of S, namely S2-, S and SO42-, on the surface of ACF-MoS2. Based on the information of Mo3d, sulphur treatment was not completely carried out and ACF-MoS2 contained both MoO₃ and MoS2.4. The vapor mercury adsorption experiments indicated ACF-MoS2 was the best adsorbent among the 9 modified samples. After modification, MoS2 and a little S were impregnated into ACF-MoS2, which enhanced the adorsption. Because of favorable thermal desorption, silver supported ACF could be regenerated and was a promising and effective adsorbent with suitable modification.