High Carbon Fly Ash as a Sorbent for the Treatment of Petroleum Contaminated Residues

The potential of using a high carbon fly ash (HCFA), an industrial byproduct, as a sorbent for hydrocarbons, in the treatment of petroleum-related liquid wastes, or as a pretreatment or addition in cement-based stabilization/solidification of petroleum-related solid wastes was assessed. An HCFA sample, whose physicochemical and leaching properties were studied in detail, was used as a test case. Batch sorption experiments were then conducted to determine the sorption capacity of HCFA using deionized water spiked with two groups of hydrocarbons typical of petroleum wastes: aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). Fourier transform infrared (FTIR) microspectroscopy was conducted to study the spatial distribution and association of hydrocarbons on the sorbent. Results indicate that HCFA has a high sorption capacity for the two groups of hydrocarbons. Data obtained fit the linear and Freundlich sorption isotherm models. FTIR microspectroscopy results showed that the hydrocarbons were preferentially sorbed onto the carbon component of HCFA rather than the siliceous components. This work shows that HCFA is potentially an inexpensive sorbent for treatment of petroleum contaminated liquid or solid wastes and contaminated soils.