Influence of surface oxides on the adsorption of naphthalene onto multiwalled carbon nanotubes.

As greater quantities of carbon nanotubes (CNTs) enter the environment, they will have an increasingly important effect on the availability and transport of aqueous contaminants. As a consequence of purification, deliberate surface functionalization, and/or exposure to oxidizing agents after release to the environment, CNTs often contain surface oxides (i.e.

Adsorption of natural organic matter onto carbonaceous surfaces: atomic force microscopy study.

The microscopic structure of carbonaceous surfaces exposed to natural organic matter (NOM) under aqueous conditions has been explored using atomic force microscopy (AFM). Dismal Swamp Water was used as the NOM source, while highly ordered pyrolytic graphite (HOPG) served as a surrogate for the graphene sheets that characterize the surface of many carbonaceous materials in aquatic environments. Under acidic conditions, the HOPG surface was covered with a densely packed monolayer of NOM molecules.

Multielectron transfer at heme-functionalized nanocrystalline TiO2: reductive dechlorination of DDT and CCl4 forms stable carbene compounds.

Hemin (chloro(protoporhyrinato)iron(III)) was found to bind to mesoporous nanocrystalline (anatase) TiO2 thin films from dimethyl sulfoxide solution, Keq=10(5) M-1 at 298 K. Band gap illumination in methanol reduced hemin to heme and led to the appearance of TiO2 electrons, heme/TiO2(e-). Reactions of heme/TiO2(e-) with CCl4 or 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT) led to the formation of stable carbene products in greater than 60% yield.

A comparison of two techniques for studying sediment desorption kinetics of hydrophobic pollutants.

A comparison of two techniques (gaseous purge and vial desorption) for studying the kinetics of desorption of hydrophobic pollutants from natural sediments was conducted using identical, pre-equilibrated pollutant-sediment suspensions. Desorption profiles for the two techniques [for Lindane, Aldrin, 2,2'-dichlorobiphenyl (2,2'-DCB), 4,4'-dichlorobiphenyl (4,4'-DCB), and 2,2',6,6'-tetrachlorobiphenyl (TCB)] were then compared, based on the distribution of pollutant mass between the labile (fast) and non-labile (slow) desorption phases and the release rate constants for each phase of release. The vial desorption technique shows many practical advantages over the gaseous purge technique, including its more realistic mixing conditions, the use of an independent sample for each data point (as opposed to a calculation of a cumulative mass purged at each time point), the fact that the vials constitute a closed system and are therefore less subject to ambient contamination, and the relatively low demands of time and money for the vial technique.