Formation of polychlorinated dibenzo-p-dioxins/dibenzofurans from residual carbon on municipal solid waste incinerator fly ash using Na37Cl.
Na37Cl was used to study the role of chlorine in the formation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) from carbon. Adding Na37Cl to fly ash showed that this compound was a (relatively) poor chloride source; chlorine naturally present on the ash - which could include both chlorine in residual carbon and (metal) chlorides - was found to be ca. 17x more reactive. When both Na37Cl and CuCl2 were added to aqueous extracted fly ash, the percentage of 37Cl from Na37Cl included in PCDD/F increased, compared to the combination of Na37Cl/fly ash. When Na37Cl and CuCl2 were exchanged in water, followed by evaporation of the solvent, and mixed with aqueous extracted fly ash, the percentage of 37Cl included in PCDD/F was much higher. Apparently, direct transfer of 37Cl from CuCl2 to carbon and PCDD/F was much faster than transfer of 37Cl- from Na37Cl via a metal chloride (such as CuCl2) to carbon and PCDD/F. In addition to chlorine in PCDD/F originating from exchanged NaCl/CuCl2, chloride left on the fly ash after aqueous extraction and chlorine present in residual carbon could also have been incorporated in PCDD/F.
Addink
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Department of Chemical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. addinr@rpi.edu
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D001572:Benzofurans / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D017745:Incineration; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry*; D012037:Refuse Disposal; D012965:Sodium Chloride / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D012997:Solvents
D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; D012997:Solvents; D012965:Sodium Chloride; D002713:Chlorine; D002244:Carbon; D003300:Copper; C029892:cupric chloride