Heteroaggregation Between Graphene Oxide and Soil Mineral Particles.

Graphene oxide (GO) has high dispersibility and likely will interact with fine mineral particles. The objective of this work was to determine how GO will interact with different types of mineral particles. The data showed GO significantly enhanced the dispersion of positively charged goethite via heteroaggregation, but no interaction between GO and negatively charged montmorillonite or kaolinite. Electrostatic attraction was a dominant force in the GO-goethite heteroaggregation, and Fe ions released from goethite did not destabilize GO suspension. Heteroaggregation between GO and goethite seems not reversible. GO sheets covered goethite particles, and a sandwich-like structure was formed as revealed from scanning and transmission electron microscopy. This work provides new insight into the controlling mechanisms of GO-mineral heteroaggregation in water and soil, and useful data for assessing the environmental fate, exposure and risk of GO.