scholarly journals Degradation of Chloramphenicol Using UV-LED Based Advanced Oxidation Processes: Kinetics, Mechanisms, and Enhanced Formation of Disinfection By-Products

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3035
Author(s):  
Xinlu Qu ◽  
Haowei Wu ◽  
Tianyang Zhang ◽  
Qianhong Liu ◽  
Mu Wang ◽  
...  

As an emerging light source, ultraviolet light emitting diodes (UV-LEDs) are adopted to overcome the shortcomings of the conventional mercury lamp, such as mercury pollution. The degradation of chloramphenicol (CAP) using three UV-LED-based advanced oxidation processes (AOPs)—UV-LED/persulfate (UV-LED/PS), UV-LED/peroxymonosulfate (UV-LED/PMS) and UV-LED/chlorine—was investigated. Results indicate that CAP can be more effectively degraded by the hybrid processes when compared to UV irradiation and oxidants alone. Degradation of CAP using the three UV-LED-based AOPs followed pseudo-first-order kinetics. The degradation rate constants (kobs) for UV-LED/PS, UV-LED/PMS, and UV-LED/chlorine were 0.0522, 0.0437 and 0.0523 min−1, and the CAP removal rates 99%, 98.1% and 96.3%, respectively. The degradation rate constant (kobs) increased with increasing oxidant dosage for UV-LED/chlorine, whereas overdosing reduced CAP degradation using UV-LED/PS and UV-LED/PMS. Ultraviolet wavelength influenced degradation efficiency of the UV-LED based AOPs with maximum CAP degradation observed at a wavelength of 280 nm. The application of UV-LED enhanced the formation DBPs during subsequent chlorination. uUV-LED/PMS produced more disinfection by-products than UV-LED/PS. Compared to UV-LED, UV-LED/PS reduced the formation of dichloroacetonitrile and trichloronitromethane during chlorination owing to its capacity to degrade the nitro group in CAP. The intermediates dichloroacetamide, 4-nitrobenzoic acid, 4-nitrophenol were produced during the degradation of CAP using each of UV-LED, UV-LED/PS and UV-LED/chlorine. The present study provides further evidence supporting the application of UV-LED in AOPs.

Author(s):  
Zahia Benredjem ◽  
Karima Barbari ◽  
Imene Chaabna ◽  
Samia Saaidia ◽  
Abdelhak Djemel ◽  
...  

Abstract The Advanced Oxidation Processes (AOPs) are promising environmentally friendly technologies for the treatment of wastewater containing organic pollutants in general and particularly dyes. The aim of this work is to determine which of the AOP processes based on the Fenton reaction is more effective in degrading the methyl orange (MO) dye. The comparative study of the Fenton, photo-Fenton (PF) and electro-Fenton (EF) processes has shown that electro-Fenton is the most efficient method for oxidizing Methyl Orange. The evolution of organic matter degradation was followed by absorbance (discoloration) and COD (mineralization) measurements. The kinetics of the MO degradation by the electro-Fenton process is very rapid and the OM degradation rate reached 90.87% after 5 min. The influence of some parameters such as the concentration of the catalyst (Fe (II)), the concentration of MO, the current density, the nature and the concentration of supporting electrolyte was investigated. The results showed that the degradation rate increases with the increase in the applied current density and the concentration of the supporting electrolyte. The study of the concentration effect on the rate degradation revealed optimal values for the concentrations 2.10−5 M and 75 mg L−1 of Fe (II) and MO respectively.


Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 612 ◽  
Author(s):  
Juan José Rueda-Márquez ◽  
Irina Levchuk ◽  
Manuel Manzano ◽  
Mika Sillanpää

The application of Fenton-based advanced oxidation processes (AOPs), such as photo-Fenton or electro-Fenton for wastewater treatment have been extensively studied in recent decades due to its high efficiency for the decomposition of persistent organic pollutants. Usually Fenton-based AOPs are used for the degradation of targeted pollutant or group of pollutants, which often leads to the formation of toxic by-products possessing a potential environmental risk. In this work, we have collected and reviewed recent findings regarding the feasibility of Fenton-based AOPs (photo-Fenton, UVC/H2O2, electro-Fenton and galvanic Fenton) for the detoxification of real municipal and industrial wastewaters. More specifically, operational conditions, relevance and suitability of different bioassays for the toxicity assessment of various wastewater types, cost estimation, all of which compose current challenges for the application of these AOPs for real wastewater detoxification are discussed.


2019 ◽  
Vol 361 ◽  
pp. 439-449 ◽  
Author(s):  
Robert Liang ◽  
Jocelyn C. Van Leuwen ◽  
Leslie M. Bragg ◽  
Maricor J. Arlos ◽  
Lena C.M. Li Chun Fong ◽  
...  

2010 ◽  
Vol 10 (1) ◽  
pp. 51-57 ◽  
Author(s):  
R. Mosteo ◽  
N. Miguel ◽  
P. Ormad Maria ◽  
J. L. Ovelleiro

Any nonylphenol compounds found in water have to be removed since they are endocrine disruptors. In this study, natural water from the river Ebro fortified with nonylphenol compounds (4n-nonylphenol and technical nonylphenol) is used as a sample in order to simulate a real situation in drinking water treatment plants. The aim is to compare conventional disinfection with advanced oxidation processes (O3, O3/H2O2, O3/TiO2 and O3/H2O2/TiO2) used for the removal of nonylphenol compounds present in natural water. Furthermore, a study is carried out of the by-products (THMs) generated as a consequence of the presence of natural organic matter. Preoxidation by chlorine completely oxidizes 4n-nonylphenol and technical nonylphenol. It can be seen that the best of the advanced oxidation processes is the O3/H2O2, achieving an average oxidation of 55%, although the differences among the processes were not very significant. Furthermore, the use of post-chlorination guarantees the total removal of nonylphenol compounds.


2018 ◽  
Vol 54 (82) ◽  
pp. 11622-11625 ◽  
Author(s):  
Xiaomei Cheng ◽  
Lianhai Zu ◽  
Yue Jiang ◽  
Donglu Shi ◽  
Xiaoming Cai ◽  
...  

A pseudo-Fenton reaction works synergistically with photocatalysis to greatly accelerate the oxidative degradation rate.


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