Chemical and toxicological properties of coal fly ash - University of ...

y passing the extract through a column of activated copper according to amethod described by Blumer (1957). After removal of the sulfur, the finaltraces of solvent were removed with gentle heat (50°C) under a stream ofdry nitrogen. The benzene-extractable material s, determinedgravimetrically, were denoted as "total extractable organics."The extracts were separated into seven fractions according to the U.S. EPALevel 1 (Revised) Procedure for Organic Analysis (U.S. €PA, 1978). Thisseparation was done by liquid chromatography (LC) on a silica gel coluinnusing a gradual gradient of solvents from nonpolar to polar. An infraredspectrum was run on each extract and on each LC fraction. Gaschromatography (GC) , high pressure 1 i quid chromatography (YPLC) , and gaschromatography-mass spectroscopy (GC-MS) were used to further characterizethe organic fractions.PyroZysis study. A 5- to 10-gram sample of fly ash was placed in thebottom of a 300-mm x 13-mm-ID Pyrex tube, and a wad of organic-free quartzwool was positioned just above the fly ash to act as a retainer. Thediameter of the tube was then constricted by heating with an oxygen-naturalgas torch just above the quartz wool retainer. The top of the tube wasthen sealed with a skirted-septum stopper and the tube was evacuated forseveral minutes, using a vacuum pump linked to the tube via a hypodermicneedle through the septum.Following the evacuation, the sample end of the tube was heated in ahorizontal position at 450°C in a tube furnace while the upper end of thetube was cooled with powdered dry ice. After a 5minute heating period thetube was immediately sealed and separated at the point of the constrictionby melting the glass with an oxygen-natural gas torch. Thus, the volatileorganics were condensed and trapped in the upper, cooled portion of thetube.The headspace gas (noncondensable at room temperature) was analyzed by GC,and the components were identified by comparison of retention times withknown standards. The condensable portion was taken up in isooctane andanalyzed by GC; one sample (derived from fly ash W1) was also analyzed byGC-MS. The major components in the samples were deterained by comparisonwith the GC-MS analysis and with the retention times of referencestandards.The infrared spectra were obtained with a Perkin-Elmer Model 283B InfraredSpectrophotometer. The samples were mounted as neat smears or thin filmsbetween sodium chloride prisms. Normally the spectra were obtained byusing a 12-minute scan time with response setting 1 and slit program 6.Interpretation of the spectra was made with the help of the followingreferences: Barnes et ale (l944), Be1 lamy (l958), Nakanishi (l962),Si lverstein and Bassler (l963), and Szymanski (1967).A rough indication of the absorption intensities in the IR spectra obtainedfrom the fly ash samples is reported in the Results Section; the absorptionintensities are given as "strong," "medi um," and "weak". "Strong" isdefined as the strongest absorption in a given spectrum. "Medium" and"weak" designations relative to the strongest absorption within the samespectrum are then determined.