Citation:

Adeleye, A., K. Ho, AND R. Burgess. Fate and transformation of graphene oxide in marine waters. American Chemical Society (ACS) 255th National Meeting, New Orleans, Louisiana, March 18 - 22, 2018.

Impact/Purpose:

Nanotechnology has continued to develop rapidly into a major industry in the United States and around the world. Nanomaterials are extremely small particles that show great potential for a variety of industrial and consumer applications but our understanding about their fate and effects in the environment is limited. Graphene oxide is a member of the graphene family nanomaterials (GFNs), which are being developed for use in functional coatings, anticorrosion applications, antifouling applications, water treatment filtration membranes, conductive inks, etc. These applications may lead to release of these nanomaterials into the environment, and there is need to understand the fate of graphene oxide (and the other GFNs) in the environment. This study focused on the fate and transformation of graphene oxide in seawater, which is predicted to be a major sink for many engineered nanomaterials. The influences of important environmental parameters—such as salinity, solar irradiation, and natural organic matter—on the fate of GO in seawater were investigated.

Description:

One common use of graphene family nanomaterials (GFNs) is as functional and/or antifouling coatings, which may ultimately lead to their release into the natural environment. The fate of graphene oxide (GO), a common type of GFN, in natural waters is currently not well understood. In particular, there is currently no study on the fate and transformation of GO in seawater, which is predicted to be a major sink for many engineered nanomaterials. In this study, the influences of salinity (0-50 ‰), aging (0 and 28 d), solar irradiation (12 and 24 h), and natural organic matter or NOM (algal exudates and humic acid) on the fate of GO in marine systems were investigated. The critical coagulation salinity of GO was determined as 1.5 ‰ but the settling velocity of GO increased with salinity up to 10 ‰. Settling velocity of GO decreased thereafter from 0.145 m/d at 10 ‰ to 0.108 m/d at 50 ‰. Stability of GO increased with increasing NOM concentrations and its transformation (reduction) decreased with elevated salinity. Carbon to oxygen ratio increased under ambient light from 1.61 in pristine GO to 2.18, 1.98, and 1.71 after 28 d in 0, 1, and 30 ‰ media, respectively. Solar irradiation caused more rapid reduction of GO but the stability of irradiated GO did not change significantly in seawater. This study showed the role of environmental parameters in the fate and transformation of GO.

Record Details: