Work

Mobilization of Manufactured Gas Plant Tar with Alkaline Flushing Solutions

Year: 2011

Type: article

Abstract: This experimental study investigates the use of alkaline and alkaline-polymer solutions for the mobilization of former manufactured gas plant (FMGP) tars. Tar-aqueous interfacial tensions (IFTs) and contact angles were measured, and column flushing experiments were conducted. NaOH solutions (0.01-1 wt.%) were found to significantly reduce tar-aqueous IFT. Contact angles indicated a shift to strongly water-wet, then to tar-wet conditions as NaOH concentration increased. Column experiments were conducted with flushing solutions containing 0.2, 0.35, and 0.5% NaOH, both with and without xanthan gum (XG). Between 10 and 44% of the residual tar was removed by solutions containing only NaOH, while solutions containing both NaOH and XG removed 81-93% of the tar with final tar saturations as low as 0.018. The mechanism responsible for the tar removal is likely a combination of reduced IFT, a favorable viscosity ratio, and tar bank formation. Such an approach may have practical applications and would be significantly less expensive than surfactant-based methods.

Source: Environmental Science & Technology

DOI: 10.1021/es202278s

Authors: Scott C. Hauswirth, Pamela Schultz Birak, Seth C. Rylander, Cass T. Miller

Institution: University of North Carolina at Chapel Hill

Language: English

Topic: Microbial bioremediation and biosurfactants

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: green

Funder: National Institute of Environmental Health Sciences