title: Mechanisms and modeling of halogenated aliphatic contaminant adsorption by carbon nanotubes.
abstract: This paper examines the adsorption of environmentally relevant halogenated aliphatic compounds using single-walled (SWCNT) and multi-walled carbon nanotubes (MWCNT), and the development of linear solvation-energy relationships (LSER) to examine those adsorption mechanisms. The poly-parameter LSER model was also compared to those previously generated for the adsorption of aromatic compounds by CNTs. The adsorption affinity of aliphatic compounds was greater on the SWCNT than MWCNT with similar oxygen contents. This was attributed to the pore-filling mechanism that was enhanced by higher micropore volume of the SWCNT bundles over the MWCNT bundles. LSER models showed that, at higher concentrations, B (the hydrogen bond accepting ability) was the most influential descriptor for both SWCNT and MWCNT. Other important descriptors were V followed by P, both of which exhibited a positive correlation with adsorption, indicating that their size and polarizability favors adsorption. The contribution of these descriptors to overall adsorption was 2-3 times less than the B. In comparison, V was the most important descriptor in the aromatic compound LSER models. This difference indicates that adsorbate hydrophobicity greatly affects the adsorption of aromatic compounds by CNTs, whereas, aliphatic compounds are affected by both the hydrophobic driving force and other interactions.
authors.affiliation: Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Court, Anderson, SC 29625, USA.
authors.forename: Onur Guven
authors.initials: OG
authors.lastname: Apul
authors.affiliation: Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Court, Anderson, SC 29625, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Court, Anderson, SC 29625, USA. Electronic address: tkaranf@clemson.edu.
authors.forename: Tanju
authors.initials: T
authors.lastname: Karanfil
mesh_terms: D000327:Adsorption; D004785:Environmental Pollutants / Q000302:isolation & purification; D006846:Hydrocarbons, Halogenated / Q000302:isolation & purification*; D008956:Models, Chemical; D037742:Nanotubes, Carbon / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D006846:Hydrocarbons, Halogenated; D037742:Nanotubes, Carbon
keywords: Adsorption; Aliphatic; Carbon nanotube; LSER; QSAR