In-situ desorption of acetaminophen from the surface of graphene oxide driven by an electric field: A study by molecular dynamics simulation

Abstract

• Electric field weakens interaction energy between GO and ACT in alkaline conditions. • Electric field destroys the hydrogen bond between GO and ACT. • Electric field reduces hydration energy barrier during the escape of ACT from GO. • Electric field makes ACT can desorb from GO surface more easily. • Electric field can change the hydrophobicity on both sides of GO. In the present study, molecular dynamics (MD) simulation was performed to study the effect of electric field on the adsorption characteristics of acetaminophen (APAP) on graphene oxide (GO) under alkaline conditions by calculating and analyzing the structural and energy parameters of a ternary system containing GO, APAP and water molecules. Our simulations result shows that when there is no electric field, the adsorption of APAP on the GO surface is mainly due to the Van de Waals interaction. When the external electric field exists, it can significantly weaken the interaction energy between GO and APAP, destroy the hydrogen bond, and reduce the hydration energy barrier during the escape of APAP from the GO surface, thereby making APAP can desorb from the GO surface more easily. In addition, the applied electric field can change the hydrophobicity on both sides of GO, which means the hydrophobicity and hydrophilicity of both sides of the GO can be switched by changing the direction and strength of the electric field. Our research results are expected to propose a novel GO regeneration method and provide a new perspective to explore the mechanism.