The relative effectiveness of seven inorganic sorbents for the capture of gaseous lead chloride was investigated by using a high-temperature packed bed sorption reactor. The investigated sorbents were alumina, bauxite, andalusite, chamotte, kaolin, pyrophyllite and silica. Except for alumina, all other tested sorbents showed good potential for the capture of lead chloride, since they were good for limiting leachability of captured lead species. Combining the two sorbent criteria of increased metal uptake on sorption and reduced leachability by the toxicity characteristic leaching procedure (TCLP), kaolin and pyrophyllite appeared to be the most-promising sorbents for lead capture. From the analysis of post-sorption sorbent samples, three different capturing mechanisms for lead capture by high-temperature inorganic sorbents were suggested: 1) chemical reaction to form water-insoluble lead-mineral complexes such as PbOㆍAl2O3ㆍ2SiO2, 2) physical adsorption of gaseous chloride to form water-soluble lead chloride (PbCl2), and 3) formation of water-insoluble lead oxide (PbO) on sorbent surface.
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