Reactive Molecular Dynamics Simulation on Degradation of Tetracycline Antibiotics Treated by Cold Atmospheric Plasmas

Abstract

The abuse of tetracycline antibiotics (TCs) has caused serious environmental pollution and risks to public health. Degradation of TCs by cold atmospheric plasmas (CAPs) is a high efficiency, low energy consumption and environmentally friendly method. In this study, a reactive molecular dynamics (MD) simulation is applied to study the interactions of reactive oxygen species (ROS) produced in CAPs and TCs (including tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC) and demeclocycline (DMC)). As revealed by the simulation data at the atomic level, the main reaction sites on TCs are the C2 acylamino, the C4 dimethylamine, the C6 methyl group, the C8 site on the benzene ring and the C12a tertiary alcohol. The interaction between ROS and TCs is usually initiated by H-abstraction, followed by the breaking and formation of the crucial chemical bonds, such as the breaking of C-C bonds, C-N bonds and C-O bonds and the formation of C=C bonds and C=O bonds. Due to the different structures of TCs, when the ROS impact OTC, CTC and DMC, some specific reactions are observed, including carbonylation at the C5 site, dechlorination at the C7 site and carbonylation at the C6 site, respectively. Some degradation products obtained from the simulation data have been observed in the experimental measurements. In addition, the dose effects of CAP on TCs by adjusting the number of ROS in the simulation box are also investigated and are consistent with experimental observation. This study explains in detail the interaction mechanisms of degradation of TCs treated by CAPs with the final products after degradation, provides theoretical support for the experimental observation, then suggests optimization to further improve the efficiency of degradation of TCs by CAPs in applications.

Impact of Polythiophene ((C4H4S)n; n = 3, 5, 7, 9) Units on the Adsorption, Reactivity, and Photodegradation Mechanism of Tetracycline by Ti-Doped Graphene/Boron Nitride (Ti@GP_BN) Nanocomposite Materials: Insights from Computational Study

“…111 According to the literature review, investigating MD simulations for adsorption and degradation is important because it gives basic insights, predicts material characteristics, and enables the rational design of effective sensing and detection of the researched TC. 112 The total energy of the system is a critical number in MD simulations that gives insights into the system's stability, bonding, and general behavior. 113 These simulations can highlight the energetics and dynamics of molecules interacting with nanocomposites, revealing binding strengths, optimal adsorption locations, and potential reaction routes.…”

“…MD simulations are a powerful computational method that uses quantum mechanical calculations in conjunction with classical molecular theory to model the behavior and characteristics of materials at the atomic scale . According to the literature review, investigating MD simulations for adsorption and degradation is important because it gives basic insights, predicts material characteristics, and enables the rational design of effective sensing and detection of the researched TC . The total energy of the system is a critical number in MD simulations that gives insights into the system’s stability, bonding, and general behavior .…”

Review on Characterization of Biochar Derived from Biomass Pyrolysis via Reactive Molecular Dynamics Simulations

“…By adopting the bond-order formalism in a classical approach, ReaxFF implicitly describes the chemical bonds without costly QM calculations, giving insight into the biomass pyrolysis process and its carbonization. It can describe the bond breaking and formation during the chemical reactions, thereby exploring the complex carbonization reaction mechanisms at a nano/microscale, including different pyrolysis processes of various feedstocks as well as other chemical process mechanisms for producing biochar or other carbonaceous materials [29,30,52,55,59,64,[76][77][78][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100], such as thermochemical reactions in combustion and energy systems [50,53,57,101], energetic and dissociative water properties under various conditions [56], properties of carbon nano-rings, carbon nanotube bundles, and crosslinked epoxy resins [66,67,102], inclusion of geometry-dependent charge calculations [75], to name a few. Biomass can produce biochar through thermochemical processes such as pyrolysis, gasification, and combustion [77].…”