title: Release of surfactant cargo from interfacially-active halloysite clay nanotubes for oil spill remediation.
abstract: Naturally occurring halloysite clay nanotubes are effective in stabilizing oil-in-water emulsions and can serve as interfacially-active vehicles for delivering oil spill treating agents. Halloysite nanotubes adsorb at the oil-water interface and stabilize oil-in-water emulsions that are stable for months. Cryo-scanning electron microscopy (Cryo-SEM) imaging of the oil-in-water emulsions shows that these nanotubes assemble in a side-on orientation at the oil-water interface and form networks on the interface through end-to-end linkages. For application in the treatment of marine oil spills, halloysite nanotubes were successfully loaded with surfactants and utilized as an interfacially-active vehicle for the delivery of surfactant cargo. The adsorption of surfactant molecules at the interface serves to lower the interfacial tension while the adsorption of particles provides a steric barrier to drop coalescence. Pendant drop tensiometry was used to characterize the dynamic reduction in interfacial tension resulting from the release of dioctyl sulfosuccinate sodium salt (DOSS) from halloysite nanotubes. At appropriate surfactant compositions and loadings in halloysite nanotubes, the crude oil-saline water interfacial tension is effectively lowered to levels appropriate for the dispersion of oil. This work indicates a novel concept of integrating particle stabilization of emulsions together with the release of chemical surfactants from the particles for the development of an alternative, cheaper, and environmentally-benign technology for oil spill remediation.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University , New Orleans, Louisiana 70118, United States.
authors.forename: Olasehinde
authors.initials: O
authors.lastname: Owoseni
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Nyankson
authors.forename: Yueheng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Adams
authors.forename: Jibao
authors.initials: J
authors.lastname: He
authors.forename: Gary L
authors.initials: GL
authors.lastname: McPherson
authors.forename: Arijit
authors.initials: A
authors.lastname: Bose
authors.forename: Ram B
authors.initials: RB
authors.lastname: Gupta
authors.forename: Vijay T
authors.initials: VT
authors.lastname: John