Sorption characteristics of polycyclic aromatic hydrocarbons in aluminum smelter residues

Journal Article · Sun Apr 01 00:00:00 EDT 2007 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es062340b· OSTI ID:20885851

Breedveld, Gijs D; Pelletier, Emilien; Louis, Richard St; Cornelissen, Gerard ^[1]

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1. Norwegian Geotechnical Institute, Oslo (Norway)

High temperature carbon oxidation in primary aluminum smelters results in the release of polycyclic aromatic hydrocarbons (PAH) into the environment. The main source of PAH are the anodes, which are composed of petroleum coke (black carbon, BC) and coal tar pitch. To elucidate the dominant carbonaceous phase controlling the environmental fate of PAH in aluminum smelter residues (coke BC and/or coal tar), the sorptive behavior of PAHs has been determined, using passive samplers and infinite-sink desorption methods. Samples directly from the wet scrubber were studied as well as ones from an adjacent 20-year old storage lagoon and roof dust from the smelter. Carbon-normalized distribution coefficients of native PAHs were 2 orders of magnitude higher than expected based on amorphous organic carbon (AOC)/water partitioning, which is in the same order of magnitude as reported literature values for soots and charcoals. Sorption isotherms of laboratory-spiked deuterated phenanthrene showed strong (about 100 times stronger than AOC) but nonetheless linear sorption in both fresh and aged aluminum smelter residues. The absence of nonlinear behavior typical for adsorption to BC indicates that PAH sorption in aluminum smelter residues is dominated by absorption into the semi-solid coal tar pitch matrix. Desorption experiments using Tenax showed that fresh smelter residues had a relatively large rapidly desorbing fraction of PAH (35-50%), whereas this fraction was strongly reduced (11-16%) in the lagoon and roof dust material. Weathering of the coal tar residue and/or redistribution of PAH between coal tar and BC phases could explain the reduced availability in aged samples. 38 refs., 5 figs., 1 tab.

• OSTI ID: 20885851
• Journal Information: Environmental Science and Technology, Vol. 41, Issue 7; Other Information: [e-mail]; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
POLYCYCLIC AROMATIC HYDROCARBONS
SORPTIVE PROPERTIES
SMELTERS
RESIDUES
ALUMINIUM
COAL TAR
PITCHES
ANODES
PETROLEUM PRODUCTS
COKE
PHENANTHRENE
DESORPTION
ADSORPTION ISOTHERMS
KINETICS
CARBON
ROOFS
DUSTS
QUANTITATIVE CHEMICAL ANALYSIS
SLUDGES
SEDIMENTS
SCRUBBERS
ORGANIC COMPOUNDS