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Generation Of Test Atmospheres And Evaluation Of Sampling Methods For Environmental Metal Aerosol Trace Analyses

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Description: The purpose of this study was twofold: to generate a reproducible lead aerosol laboratory test atmosphere that could simulate lead fumes, and to investigate the use of packed bed solid sorbent tubes for the collection and concentration of lead aerosols utilizing the test atmosphere and a sample atmosphere. An evaporation-condensation generator was designed and employed to produce the lead aerosol test atmosphere, while automobile exhaust was used as a sample atmosphere. Aerosol production was characterized using electron microscopy, X-ray fluorescence, X-ray diffraction, and atomic absorption spectroscopy. Experimental characterization included particle size, shape, chemical composition and chemical structure determination. Optimum flow rates and temperatures were determined for the dynamic lead aerosol generator in order to produce reproducible concentrations and particle size ranges. Within-day average deviation in concentration was 3% and day-to-day with dismantling and shutdown was 20%. For the second part of the study, pyrex tubes were packed with portions of four different sorbents (one sorbent type per tube) separated by glass wool. The sorbents tested were alumina (100-150 mesh), silica gel (80-200 mesh), Chromosorb 102 (60-80 mesh), and Tenax-GC (80-100 mesh). The following average efficiencies were observed for the first portion of each tube (200 mg of sorbent) when sampling automobile exhaust: 95.8 (+OR-) 5.7% for alumina, 98.5 (+OR-) 3.2% for silica gel, 98.0 (+OR-) 3.7% for Chromosorb 102, and 99.2 (+OR-) 2.6% for Tenax-GC. Using the lead metal test aerosol, the average efficiencies were 99.2, 99.2, 99.9, and 100.0% for the alumina, silica gel, Chromosorb 102, and Tenax-GC, respectively. Consideration of percent efficiency of collection, blank values, and elution efficiency of lead from the sorbent indicates that Tenax-GC provided the best results.
Language: English
Format: Degree Work