Electronic-property dependent interactions between tetracycline and graphene nanomaterials in aqueous solution
Lin He , Fei-fei Liu , Mengyao Zhao , Zhen Qi , Xuefei Sun , Muhammad Zaheer Afzal , Xiaomin Sun , Yanhui Li , Jingcheng Hao , Shuguang Wang
DOI:10.1016/j.jes.2017.04.030
Received December 23, 2016,Revised April 27, 2017, Accepted April 27, 2017, Available online May 09, 2017
Volume 30,2018,Pages 286-294
Understanding the interactions between graphene nanomaterials (GNMs) and antibiotics in aqueous solution is critical to both the engineering applications of GNMs and the assessment of their potential impact on the fate and transport of antibiotics in the aquatic environment. In this study, adsorption of one common antibiotic, tetracycline, by graphene oxide (GO) and reduced graphene oxide (RGO) was examined with multi-walled carbon nanotubes (MWCNTs) and graphite as comparison. The results showed that the tetracycline adsorption capacity by the four selected carbonaceous materials on the unit mass basis followed an order of GO > RGO > MWCNTs > graphite. Upon normalization by surface area, graphite, RGO and MWCNTs had almost the same high tetracycline adsorption affinity while GO exhibited the lowest. We proposed π-electron-property dependent interaction mechanisms to explain the observed different adsorption behaviors. Density functional theory (DFT) calculations suggested that the oxygen-containing functional groups on GO surface reduced its π-electron-donating ability, and thus decreased the π-based interactions between tetracycline and GO surface. Comparison of adsorption efficiency at different pH indicated that electrostatic interaction also played an important role in tetracycline-GO interactions. Site energy analysis confirmed a highly heterogeneous distribution of the binding sites and strong tetracycline binding affinity of GO surface.
