Oxidation of disinfectants with Cl-substituted structure by a Fenton-like system Cu2+/H2O2 and analysis on their structure-reactivity relationship

Abstract

As widely used chemicals intended to protect human being from infection of microorganisms, disinfectants are ubiquitous in the environment. Among them chlorine-substituted phenol is a basic structure in many disinfectant molecules. Removal of these pollutants from wastewater is of great concern. The oxidative degradation of antimicrobial agents such as triclosan, chlorofene, and dichlorofene by a Fenton-like system Cu(2+)/H2O2 was examined. Reaction conditions such as temperature, initial concentrations of H2O2 and Cu(2+), and pH were optimized using triclosan as a representative. The degradation kinetics of the above disinfectants followed pseudo-first-order kinetics under the investigated conditions. Fourteen chlorophenols (CPs) with different chlorine substitution were also studied to evaluate the influence of molecular structure on the degradation process in the Cu(2+)/H2O2 system. Fourteen structure-related parameters were calculated using Gaussian 09 program. A quantitative structure-activity relationship (QSAR) model was established using SPSS software with measured rate constant (k) as dependent variable and calculated molecular descriptors as independent variables. A three-parameter model including energy of HOMO (E homo), molar heat capacity at constant volume (Cv(θ)), and the most positive net charge of hydrogen atoms (qH(+)) was selected for k prediction, with correlation coefficient R(2) = 0.878. Analyses of the model demonstrated that the Cv(θ) was the most significant factor affecting the k of chlorophenols. Variance analysis and standard t-value test were used to validate the model.

Laser Ablation for the Synthesis of Cu/Cu2O/CuO and Its Development as Photocatalytic Material for Escherichia coli Detoxification

“…With and without light, Cu species are present, and in the presence of H 2 O 2 and light, it rapidly oxidizes to Cu(II). Conditions that could favor the release of hydroxyl radicals in the presence of intracellular H 2 O 2 are shown in Figure 3E [32][33][34][35].…”

El empleo de las radiaciones ionizantes y no ionizantes en el tratamiento de aguas residuales contaminadas con benzodiacepinas

“…La integración de estos dos procesos es conceptualmente ventajosa en el tratamiento de aguas residuales partiendo de que puede eliminar las desventajas asociadas a cada proceso individual. Las investigaciones realizadas hasta el momento muestran resultados prometedores en la degradación de contaminantes como pesticidas, tintes, fármacos y compuestos orgánicos complejos, como son la diazina, el dimetoato, el carbofurano, la antraquinona (Azul ácido 25, BA25), el fenitrotion, los azo-colorantes, como la rodamina B, el azul de metileno y la metilnaranja, el diclofenaco, el naproxeno y el paracetamol (Jyothi, Yesodharan, & Yesodharan, 2018;Mackuľak et al, 2015;Peng, Li, Shi, Wang, & Gao, 2016;Saharan, Chaudhary, Lata, Mehta, & Mor, 2015;Soltani & Entezari, 2013;Torrades & García-Montaño, 2014).…”

A review of quantitative structure–property relationships for the fate of ionizable organic chemicals in water matrices and identification of knowledge gaps

“…94,95 For example, Bronner and Goss (2011) 82 108 for benzene structures with different substitute groups and other heterocycles containing nitrogen or sulfur (N ¼ 60; r 2 ¼ 0.803) using Dragon and QC descriptors (semi-empirical and using DFT at the B3LYP theory level and 6-31G(d,p) basis set). Peng et al 106 used physicochemical and quantum chemical (Gaussian) descriptors to predict rst-order degradation rate constants for antimicrobial agents (r 2 ¼ 0.878) in a Fenton system using Cu 2+ / H 2 O 2 . Though the descriptors used were heterogeneous, the energy of the highest occupied molecular orbital (E HOMO ) recurred in two QSPRs as well as QSPRs for other abiotic reactions.…”

“…Though the descriptors used were heterogeneous, the energy of the highest occupied molecular orbital (E HOMO ) recurred in two QSPRs as well as QSPRs for other abiotic reactions. [104][105][106]108 All used descriptors relate to the relative importance of rate limiting steps of the reactions with hydroxyl radicals (*OH), e.g. bond breaking, H-abstraction, transition state formation, steric interactions and diffusion.…”