Do We Still Need a Laboratory to Study Advanced Oxidation Processes? A Review of the Modelling of Radical Reactions used for Water Treatment

Abstract

Environmental pollution due to humankind’s often irresponsible actions has become a serious concern in the last few decades. Numerous contaminants are anthropogenically produced and are being transformed in ecological systems, which creates pollutants with unknown chemical properties and toxicity. Such chemical pathways are usually examined in the laboratory, where hours are often needed to perform proper kinetic experiments and analytical procedures. Due to increased computing power, it becomes easier to use quantum chemistry computation approaches (QCC) for predicting reaction pathways, kinetics, and regioselectivity. This review paper presents QCC for describing the oxidative degradation of contaminants by advanced oxidation processes (AOP, i.e., techniques utilizing •OH for degradation of pollutants). Regioselectivity was discussed based on the Acid Blue 129 compound. Moreover, the forecasting of the mechanism of hydroxyl radical reaction with organic pollutants and the techniques of prediction of degradation kinetics was discussed. The reactions of •OH in various aqueous systems (explicit and implicit solvation) with water matrix constituents were reviewed. For example, possible singlet oxygen formation routes in the AOP systems were proposed. Furthermore, quantum chemical computation was shown to be an excellent tool for solving the controversies present in the field of environmental chemistry, such as the Fenton reaction debate [main species were determined to be: •OH < pH = 2.2 < oxoiron(IV)]. An ongoing discussion on such processes concerning similar reactions, e.g., associated with sulphate radical-based advanced oxidation processes (SR-AOP), could, in the future, be enriched by similar means. It can be concluded that, with the rapid growth of computational power, QCC can replace most of the experimental investigations related to the pollutant’s remediation in the future; at the same time, experiments could be pushed aside for quality assessment only.

Eco-Technology and Eco-Innovation for Green Sustainable Growth

“…In order to understand the impact of human activity on nature, scholars have contributed 10 research articles, presented in this special issue of the Ecological Chemistry and Engineering S (ECES). Specifically, Wacławek [2] provided an overview of the existing computational methods for describing the oxidative degradation of pollutants in terms of advanced oxidation processes (AOP, i.e., techniques utilizing OH radical for degradation of pollutants). The regioselectivity of the Acid Blue 129 compound is discussed as an example, and it was concluded that with the development of the information technology age, quantum chemical calculations (QCC) will not only become more accurate and accessible, but will also replace most of the experimental studies related to pollutant remediation in the future.…”

Fabrication of hybrid polystyrene–titanium dioxide with enhanced dye degradation and antimicrobial properties: investigation of the effect of triethylene glycol dimethacrylate on photocatalytic activity

“…Then, the hydroxyl radicals () and the superoxide radicals () were generated by UV light. The electron transfer between dye and the radicals on the surface accelerated the photodegradation rate of the reaction 48,49 . The photocatalysis of PS/TiO 2 in the presence of TEGDMA was increased due to the TEGDMA association with the self‐organization structure of the hybrid system, as seen in the SEM image in Fig.…”

Novel Biogenic Synthesis of a Ag@Biochar Nanocomposite as an Antimicrobial Agent and Photocatalyst for Methylene Blue Degradation

“…As a result of visible-light irradiation of the Ag@biochar nanocomposite, electron–hole pairs were formed due to the SPR phenomenon of AgNPs generating ROS such as superoxide anions ( • O 2 – ) and hydroxyl radicals ( • OH) via the reaction of free electrons (e – ) with oxygen and the reaction of h + with H 2 O molecules adsorbed onto the Ag@biochar nanocomposite, respectively, which in turn initiate the photocatalytic degradation of the adsorbed MB molecules. Moreover, the reaction of visible light with oxygen (O 2 ) could result in the formation of other ROS such as the singlet oxygen ( 1 O 2 ) that further improves the photodegradation of MB. , A schematic representation of the possible mechanism for the photocatalytic degradation of MB on Ag@biochar is shown in Figure S4 …”