Exploration of the Binding Properties of the Azo Dye Pollutants with Nitrogen‐Doped Graphene Oxide by Computational Modeling for Wastewater Treatment Improvement

Abstract

AbstractSystematic studies were carried out to investigate the binding properties of ten selected azo dye pollutants with nitrogen‐doped graphene oxide. Acid Blue 29, Acid Orange 5, Acid Orange 7, Acid Orange 8, Acid Orange 52, Blue 113, Direct Blue 71, hydrolyzed Reactive Black 5H, hydrolyzed Reactive Orange 16H, and hydrolyzed Reactive Orange 107H were selected to be studied. At the first step, docking studies were done to provide the best binding modes between azo dye and nitrogen–doped graphene oxide. In continue, molecular dynamics simulation method, molecular mechanics/generalized Born and surface area (MM/GBSA) analysis, and energy decomposition analysis were carried out to examine the strength and nature of interactions between azo dye pollutants and nitrogen–doped graphene oxide. Analyzing of interaction during molecular dynamics simulation showed that van der Waals interaction has the most important role on the binding of the azo dyes to the surface of the nitrogen‐doped graphene oxide. Also, the contribution of electrostatic and hydrogen bonding interactions are not ignorable. The –SO3H, –OH, and –NH2 moieties on the azo dyes have a contribution in hydrogen bonding with the epoxide and –OH functional groups and pyridinium–like and pyrrole–like nitrogen‐containing functional groups on the nitrogen‐doped graphene oxide. No contributions from the carboxylic acid moieties and graphite‐like nitrogen‐containing functional groups in the hydrogen bonding were observed. The binding energies related to ADs/NGO systems during the MD simulation process, calculated by MM/GBSA approach. Entry Azo dye Binding energy (kcal mol–1) 1 Acid Blue 29 –42.7 2 Acid Orange 5 –32.6 3 Acid Orange 7 –30.1 4 Acid Orange 8 –32.2 5 Acid Orange 52 –28.3 6 Blue 113 –55.2 7 Direct Blue 71 –67.3 8 Hydrolyzed Reactive Black 5H –30.2 9 Hydrolyzed Reactive Orange 16H –32.6 10 Hydrolyzed Reactive Orange 107H –27.0