Degradation kinetics and mechanism of oxytetracycline by hydroxyl radical-based advanced oxidation processes

2016 ◽  
Vol 284 ◽  
pp. 1317-1327 ◽  
Author(s):  
Yiqing Liu ◽  
Xuexiang He ◽  
Yongsheng Fu ◽  
Dionysios D. Dionysiou
2010 ◽  
Vol 94 (3-4) ◽  
pp. 288-294 ◽  
Author(s):  
Taicheng An ◽  
Hai Yang ◽  
Guiying Li ◽  
Weihua Song ◽  
William J. Cooper ◽  
...  

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3398 ◽  
Author(s):  
John F. Guateque-Londoño ◽  
Efraím A. Serna-Galvis ◽  
Yenny Ávila-Torres ◽  
Ricardo A. Torres-Palma

In this work, the degradation of the pharmaceutical losartan, in simulated fresh urine (which was considered because urine is the main excretion route for this compound) by sonochemistry and UVC/H2O2 individually, was studied. Initially, special attention was paid to the degrading action of the processes. Then, theoretical analyses on Fukui function indices, to determine electron-rich regions on the pharmaceutical susceptible to attacks by the hydroxyl radical, were performed. Afterward, the ability of the processes to mineralize losartan and remove the phyto-toxicity was tested. It was found that in the sonochemical treatment, hydroxyl radicals played the main degrading role. In turn, in UVC/H2O2, both the light and hydroxyl radical eliminated the target contaminant. The sonochemical system showed the lowest interference for the elimination of losartan in the fresh urine. It was established that atoms in the imidazole of the contaminant were the moieties most prone to primary transformations by radicals. This was coincident with the initial degradation products coming from the processes action. Although both processes exhibited low mineralizing ability toward losartan, the sonochemical treatment converted losartan into nonphytotoxic products. This research presents relevant results on the elimination of a representative pharmaceutical in fresh urine by two advanced oxidation processes.


2018 ◽  
Vol 7 (1) ◽  
pp. 61-67
Author(s):  
Do Ngoc Khue ◽  
Tran Dai Lam ◽  
Dao Duy Hung ◽  
Vu Quang Bach ◽  
Nguyen Van Anh ◽  
...  

AbstractSeveral advanced oxidation processes have been performed for the decomposition of ester nitrates (ENs), such as nitroglycerine (NG) and pentaerythritol tetranitrate (PETN). The reaction kinetics for removing NG and PETN by some of the advanced oxidation processes (e.g. UV-H2O2, Fenton, UV-Fenton) followed the pseudo-first-order model. The reaction rates in different systems followed the sequence ENs/UV<ENs/H2O2<ENs/UV-H2O2<ENs/Fenton<ENs/UV-Fenton. The effect of various parameters, such as pH, concentration of hydrogen peroxide, and temperature, on the degradation of NG and PETN were studied.


2021 ◽  
Author(s):  
Donghai Yuan ◽  
Guangyu Liu ◽  
Fei Qi ◽  
Jinggang Wang ◽  
Yingying Kou ◽  
...  

Abstract Effluent Organic Matter (EfOM) contains a large number of substances that are harmful to both the environment and human health. To avoid the negative effects of organic matter in EfOM, advanced treatment of organic matter is an urgent task. Four typical oxidants (H2O2, PS, PMS, NaClO) and UV-combined treatments were used to treat micro-contaminants in the presence or absence of effluent organic matter (EfOM), because the active radical species produced in these UV-AOPs are highly reactive with organic contaminants. However, the removal efficiency of trace contaminants was greatly affected by the presence of EfOM. The degradation kinetics of two representative micro-contaminants (benzoic acid (BA) and para-chlorobenzoic acid(p-CBA)) was significantly reduced in the presence of EfOM, compared to the degradation kinetics in its absence. Using the method of competitive kinetics, with BA, p-CBA and 1,4-dimethoxybenzene (DMOB) as probes, the radicals (HO·, SO4-·, ClO·) proved to be the key to reaction species in advanced oxidation processes. UV irradiation on EfOM was not primarily responsible for the degradation of micro-contaminants. The second-order rate constants of the EfOM with radicals were determined to be (5.027±0.643)×102(SO4-·), (3.192±0.153)×104 (HO·) and 1.35×106 (ClO·) (mg-C/L)-1·s-1. In addition, this study evaluated the production of three radicals based on the concept of Rct, which can better analyze its reaction mechanism.


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