Partially reduced graphene oxide as an efficient adsorbent towards ionic dyes and interaction mechanism

Abstract

Graphene based adsorbent has fascinating perspective in environmental application. Herein, partially reduced graphene oxide (PRGO) was facilely prepared with hydrothermal method. The as prepared PRGO was characterized and utilized as adsorbent to remove Congo red (CR) and malachite green (MG). Moreover, adsorption mechanism was elaborately surveyed via adsorption fitting (isotherm, kinetic and thermodynamic) and spectroscopic analysis (FTIR, UV-Vis). Results show, CR, MG adsorption by PRGO swiftly reaches equilibrium in 8 min and 10 min, with adsorption quantity 121.29 mg g−1 and 198.10 mg g−1 respectively. Both adsorptions are chemically favorable as satisfactorily described by the Freundlich model and pseudo second order model in equilibrium level and non equilibrium level, respectively. With regard to adsorption mechanism, adsorption is associated with both polar and non polar interactions. For CR adsorption, the specific form of polar and non polar interaction is hydrogen bond and π-π interaction, respectively. While for MG adsorption, the specific form of polar and non polar interaction is electrostatic attraction and π-π interaction, respectively. This work may provide insight for exploiting graphene related adsorbent for environmental treatment.