title: Interactions of 14C-labeled multi-walled carbon nanotubes with soil minerals in water.
abstract: Carbon nanotubes are often modified to be stable in the aqueous phase by adding extensive hydrophilic surface functional groups. The stability of such CNTs in water with soil or sediment is one critical factor controlling their environmental fate. We conducted a series of experiments to quantitatively assess the association between water dispersed multi-walled carbon nanotubes (MWCNTs) and three soil minerals (kaolinite, smectite, or shale) in aqueous solution under different sodium concentrations. (14)C-labeling was used in these experiments to unambiguously quantify MWCNTs. The results showed that increasing ionic strength strongly promoted the removal of MWCNTs from aqueous phase. The removal tendency is inversely correlated with the soil minerals' surface potential and directly correlated with their hydrophobicity. This removal can be interpreted by the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory especially for kaolinite and smectite. Shale, which contains large and insoluble organic materials, sorbed MWCNTs the most strongly.
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA.
authors.forename: Liwen
authors.initials: L
authors.lastname: Zhang
authors.forename: Elijah J
authors.initials: EJ
authors.lastname: Petersen
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Chen
authors.forename: Miguel
authors.initials: M
authors.lastname: Cabrera
authors.forename: Qingguo
authors.initials: Q
authors.lastname: Huang
mesh_terms: D000327:Adsorption; D002250:Carbon Radioisotopes; D057927:Hydrophobic and Hydrophilic Interactions; D008903:Minerals / Q000737:chemistry*; D008956:Models, Chemical; D037742:Nanotubes, Carbon / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D002250:Carbon Radioisotopes; D008903:Minerals; D037742:Nanotubes, Carbon; D012987:Soil; D014874:Water Pollutants, Chemical; D014867:Water