# Single-layer graphene oxide film grown on α-Al2O3(0001) for use as an adsorbent

## TL;DR

Single-layer graphene oxide on α-Al2O3(0001) is shown to be an effective adsorbent for cesium in water.

## Contribution

Demonstration of single-layer graphene oxide's high cesium adsorption capacity in aqueous solutions.

## Key findings

- Cesium adsorbs on oxygen functional groups of single-layer graphene oxide by substituting hydrogen atoms.
- The weight adsorption capacity of single-layer graphene oxide for cesium is approximately 70 wt% in 1.0 mol/L solution.

## Abstract

Graphene oxide (GO) is expected to be one of the most promising adsorbents for metal ions, including radioactive nuclides in aqueous solutions. Large-area and single-layer graphene oxide (SLGO) grown on α-Al2O3(0001) was used as a model structure of GO since the aggregation and re-stacking of the GO sheets prevent the adequate analysis of the adsorption state. The SLGO film was obtained by oxidizing monolayer graphene grown by metal-free chemical vapor deposition on the α-Al2O3(0001) surface, and the adsorption state was determined by surface analytical techniques. It was clarified that Cs adsorbs on oxygen functional groups by substituting with H atoms from carboxyl and hydroxy groups. It is also estimated that the weight adsorption capacity of SLGO in the 1.0 mol/L-Cs aqueous solution is as much as approximately 70 wt %. It has been demonstrated that GO has great potential to be a promising adsorbent for Cs in aqueous solutions.