Mercury removal with impregnated

Sulfur Compound Removal with Impregnated Carton, 1126 Mercury Removal with Impregnated Carbon, 1127... 

MEDISORBON An adsorptive process for removing mercury and dioxins from flue-gas. The adsorbent is a dealuminated zeolite Y manufactured by Degussa. For mercury removal, the zeolite is impregnated with sulfur. Developed in 1994 by Lurgi Energie und Umwelt and piloted in Germany and The Netherlands. 

Choi J-W, Yang K-S, Kim D-J, Lee CE (2009) Adsorption of zinc and toluene by alginate complex impregnated with zeolite and activated carbon. Curr Appl Phys 9(3) 694-697 Chojnacki A, Chojnacka K, Hoffmann J, Gorecki H (2004) The application of natural zeolites for mercury removal from laboratory tests to industrial scale. Min Eng 17(7-8) 933-937 Clancy JL, Hargy TM, Marshall MM, Dyksen JE (1998) UV light inactivation of Cryptosporidium oocysts. J Am Water Works Assoc 90(9) 92-102... 

Some natural gases have also been found to contain mercury, which is a reformer catalyst poison when present in sufftciendy large amounts. Activated carbon beds impregnated with sulfur have been found to be effective in removing this metal. 

BMS A process for removing mercury from the effluent from the Castner-Kellner process. Chlorine is used to oxidize metallic mercury to the mercuric ion, and this is then adsorbed on activated carbon impregnated with proprietary sulfur compounds. Developed by Billingsfors Bruks, Sweden. 

Zeolites have also proven applicable for removal of nitrogen oxides (NO ) from wet nitric acid plant tail gas (59) by the UOP PURASIV N process (54). The removal of NO from flue gases can also be accomplished by adsorption. The Unitaka process utilizes activated carbon with a catalyst for reaction of NO, with ammonia, and activated carbon has been used to convert NO to N02, which is removed by scrubbing (58). Mercury is another pollutant that can be removed and recovered by TSA. Activated carbon impregnated with elemental sulfur is effective for removing Hg vapor from air and other gas streams the Hg can be recovered by ex situ thermal oxidation in a retort (60). The UOP PURASIV Hg process recovers Hg from clilor-alkali plant vent streams using more conventional TSA regeneration (54). Mordenite and clinoptilolite zeolites are used to remove HQ from Q2, clilorinated hydrocarbons, and reformer catalyst gas streams (61). Activated aluminas are also used for such applications, and for the adsorption of fluorine and boron—fluorine compounds from alkylation (qv) processes (50). 

Mercury is one of a number of toxic heavy metals that occur in trace amounts in fossil fuels, particularly coal, and are also present in waste materials. During the combustion of fuels or wastes in power plants and utility boilers, these metals can be released to the atmosphere unless remedial action is taken. Emissions from municipal waste incinerators can substantially add to the environmental audit of heavy metals, since domestic and industrial waste often contains many sources of heavy metals. Mercury vapor is particularly difficult to capture from combustion gas streams due to its volatility. Some processes under study for the removal of mercury from flue gas streams are based upon the injection of finely ground activated carbon. The efficiency of mercury sorption depends upon the mercury speciation and the gas temperature. The capture of elemental mercury can be enhanced by impregnating the activated carbon with sulfur, with the formation of less volatile mercuric sulfide [37] this technique has been applied to the removal of mercury from natural gas streams. One of the principal difficulties in removing Hg from flue gas streams is that the extent of adsorption is very low at the temperatures typically encountered, and it is often impractical to consider cooling these large volumes of gas. 

As the water formed is removed axeotropically, the mercury impregnated Nafion-H catalyst can be recovered by filtration without any loss of activity and can be recycled. Comparison of data with nitration in the absence of mercury catalyst shows that formation of less hindered isomeric nitroarenes are favored. It is interesting to note that attempted azeotropic nitration of ethylbenzene with nitric acid/Nafion-H yielded only acetophenone via side-chain oxidation, whereas in the presence of mercury salt under similar reaction conditions, niiroethylbenzenes were obtained in good yield with only 13% of product of side chain oxidation. 

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