Desorption and mobility mechanisms of co-existing polycyclic aromatic hydrocarbons and heavy metals in clays and clay minerals. (15th May 2018)

• Record Type: Journal Article
• Authors: Saeedi, Mohsen; Li, Loretta Y.; Grace, John R.
• Is Part Of: Journal of environmental management. Volume 214(2018)
• Page Start: 204
• Page End: 214
• Publication Date: 2018-05-15
• Subjects: Heavy metals -- PAHs -- Desorption and mobility -- Clayey minerals -- Kaolinite -- Bentonite; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2018.02.065
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The effects of soil components such as clay minerals and as humic acids, as well as co-existing metals and polycyclic aromatic hydrocarbons, on desorption and mobility are examined. Three types of artificially blended clay and clay mineral mixtures (pure kaolinite, kaolinite + sand and kaolinite + sand + bentonite), each with different humic acid content, were tested for desorption and mobility of acenaphthene, fluorene and fluoranthene by three extracting solutions CaCl2 (0.01 M) and EDTA (0.01M) with non-ionic surfactants (Tween 80 and Triton X100). Heavy metals (Ni, Pb and Zn) were also studied for desorption and mobility. The influence of co-present metals on simultaneous desorption and mobility of PAHs was investigated as well. The results showed that <10% of metals in the clay mineral mixtures were mobile. Combined EDTA and non-ionic solutions can enhance the desorption and mobility of PAHs to >80% in clay mineral mixtures containing no sand, while in the same soils containing ∼40% sand, the desorption exceeded 90%. Heavy metals, as well as increasing humic acids content in the clay mineral mixtures, decreased the desorption and mobility of PAHs, especially for soils containing no sand, and for fluoranthene compared with fluorene and acenaphthene. Highlights: Organic matter in clay mineral mixtures reduces the mobility and removal of PAHs and heavy metals. Presence of heavy metals in clay mineral mixtures decreases PAHs mobility and removal. Clay content of the soils intensifies OM/metal effects on decreasing PAHs removal. Non-ionic enhancing solutions increase simultaneous PAHs and metals removal.