DFT Calculation of Nonperiodic Small Molecular Systems to Predict the Reaction Mechanism of Advanced Oxidation Processes: Challenges and Perspectives

Abstract

Advanced oxidation processes (AOPs) have a broad range of potential applications in the treatment of emerging refractory emerging pollutants. However, due to the presence of highly reactive substances such as free radicals that are difficult to capture, it is challenging to investigate the mechanism of AOPs at the elementary reaction level. The conventional methods, such as electron spin resonance (ESR), free radical quantification, and free radical quenching, are plagued by systematic issues that have led to bottlenecks in the field of AOP studies. The development of computational chemistry theory and computer performance provides a new method to study the mechanism of AOPs through density functional theory (DFT) calculation. Due to its excellent cost–performance benefit, DFT calculations for aperiodic small molecules have become popular in the field of AOPs. In this paper, a comprehensive review is presented on the applications of DFT calculations for predicting active sites and exploring reaction selectivity and oxidant activation mechanisms. A systematic classification of methods related to molecular descriptors and transition states is provided. Furthermore, some current research issues are identified, and future development prospects and challenges are discussed.

Peroxydisulfate-Driven Reductive Dechlorination as Affected by Soil Constituents: Free Radical Formation and Conversion

“…Gibbs free energy (G) was obtained by summing the single point energy of each compound with the previously calculated free energy correction terms, and the resulting Gibbs free energy change (Δ G ) could provide a description of the chemical reaction that is either spontaneous (Δ G < 0) or endergonic (Δ G > 0) . From eq , one obtains the Δ G values of oxidation processes as normalΔ G = G normalp normalr normalo normald normalu normalc normalt − G normalr normale normala normalc normalt normala normaln normalt …”