Simultaneous dispersion-dissolution behavior of concentrated silver nanoparticle suspensions in the presence of model organic solutes.

The premise of the nanotechnology revolution is based on the increased surface reactivity of nanometer-sized particles. Thus, these newly realized applications of noble metal nanoparticles introduce new concerns about the environmental fate of these materials if released during use or product disposal. In this paper, the focus is on silver nanoparticles, a known biocidal agent.

Surfactive stabilization of multi-walled carbon nanotube dispersions with dissolved humic substances.

Soil humic substances (HS) stabilize carbon nanotube (CNT) dispersions, a mechanism we hypothesized arose from the surfactive nature of HS. Experiments dispersing multi-walled CNT in solutions of dissolved Aldrich humic acid (HA) or water-extractable Catlin soil HS demonstrated enhanced stability at 150 and 300 mg L(-1) added Aldrich HA and Catlin HS, respectively, corresponding with decreased CNT mean particle diameter (MPD) and polydispersivity (PD) of 250 nm and 0.3 for Aldrich HA and 450 nm and 0.