The use of carbon based materials on the removal of antibiotics with high concentrations has been well studied, however the effect of this removal method is not clear on the actual concentration of environments, such as the hospital wastewater, sewage treatment plants and aquaculture wastewater. In this study, experimental studies on the adsorption of 7 antibiotics in environmental concentration of aqueous solutions by carbon based materials have been observed. Three kinds of carbon materials have shown very fast adsorption to antibiotics by liquid chromatography–tandem mass spectrometry (LC-MS-MS) detection and the highest removal efficiency of antibiotics could reach to 100% within the range of detection limit. Surprisedly, the adsorption rate of graphene with small specific surface area was stronger than other two biochar and adsorption rate of the two biochar which have approximate specific surface and different carbonization degree, was significantly different. The key point to the present observation were the π-π interactions between aromatic rings on adsorbed substance and carbon based materials by confocal laser scanning microscope observation. Moreover, adsorption energy markedly increased with increasing number of the π rings by using the density functional theory (DFT), showing the particular importance of π-π interactions in the adsorption process.

Several studies have shown that the fundamental principle of biosensors for DNA detection based on graphene oxide (GO) is the preferential adsorption of single-stranded DNA (ssDNA) over double-stranded DNA (dsDNA) on GO. However, the interactions between DNA and GO at the atomic level are poorly understood, and molecular dynamics (MD) simulation can be used to further explore these interactions. In the current study, we performed MD simulations to investigate the dynamic process of both ssDNA and dsDNA adsorption onto GO and pristine graphene (PG). We found that ssDNA was firmly adsorbed and lay flat on the surface of PG and GO, whereas dsDNA was preferentially oriented upright on both surfaces, resulting in weaker adsorption energies. Exploration of the mechanism of DNA segments binding to PG and GO indicated that π – π stacking interaction was the dominant force in the adsorption of DNA segments on PG, while both π – π stacking and hydrogen bonding contributed to the binding affinity between DNA segments and GO. These findings are of significant importance to the understanding of the interactions between DNA and GO, and the optimization of DNA and GO-based biosensors.