Effects of humic acid and electrolytes on photocatalytic reactivity and transport of carbon nanoparticle aggregates in water

The effects of naturally occurring macromolecules such as humic acid (HA) and electrolytes on four fullerene nanoparticle suspensions (i.e., C60, C60(OH)24, single- and multiwall carbon nanotubes) were explored with respect to: (1) characteristics of nanoparticle aggregates, (2) transport of the aggregates through a silica porous media, and (3) production of reactive oxygen species (ROS) from the photosensitized fullerene aggregates. The presence of HA and salts increased the size of aggregates and relative hydrophobicity associated with transport through silica beads, while decreasing ROS production. These data illustrate the importance that transformation of engineered nanomaterials (ENMs) through interactions with aquatic solutes may have in altering the environmental behavior of nanomaterials.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (145 K)Download as PowerPoint slideHighlights► We explore the effects of humic acid and cations on fullerene nanoparticle aggregates. ► Humic acid increases the stability of the fullerene aggregates. ► Humic acid retards the ROS production of fullerene aggregates. ► Cations decrease ROS production and mobility of the aggregates by increasing size.