scholarly journals Oxidación electroquímica para la degradación de ciprofloxacíno asistida con radiación ultravioleta utilizando ánodos dimensionalmente estables

2020 ◽  
Author(s):  
◽  
Angel Eduardo Yañez Rios
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
High Performance ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Visible Spectroscopy ◽  
Oxidation Processes ◽  
Dimensionally Stable Anode

Numerosos reportes han descrito un aumento de los productos farmacéuticos y de cuidado personal, detectados en diversos cuerpos de agua durante los últimos años. Su continua detección es un riesgo, ya que puede significar una afectación directa hacia el ecosistema. La presencia de este tipo de contaminantes en efluentes de plantas de tratamiento de aguas residuales, demuestran las bajas eficiencias de degradación por los métodos convencionales. Debido a lo anterior, alternativas como los procesos de oxidación avanzada (AOPs, Advanced Oxidation Processes) han ganado interés, por la producción de especies oxidantes capaces de degradar compuestos altamente recalcitrantes. El acoplar dos o más AOPs, puede favorecer el aumento en la producción de agentes oxidantes (HOCl, .OH), así como incrementar la eficiencia de degradación y mineralización de contaminantes. Con este último propósito, se realizó la degradación de ciprofloxacino (20 ppm) al implementar un sistema electroquímico foto-asistido, donde se utilizó un electrodo de RuO2 como ánodo dimensionalmente estable (DSA, Dimensionally Stable Anode), sintetizado mediante el método de Pechini, en conjunto con una fuente de radiación de 254 nm y soluciones de 0.05M de NaCl como fuente de cloruros. Además, se estudió el comportamiento del sistema foto-electrocatalítico en condiciones de pH 3, 6 y 9, con ayuda de la imposición de densidades de corriente de 5 y 10 mA cm−2, ocurriendo entonces, la electrogeneración de especies de cloro activo, así como reacciones de homólisis de las mismas para la degradación del ciprofloxacino. Los productos de los sistemas se evaluaron por medio de espectroscopía UV (UV-Vis, Ultraviolet-Visible Spectroscopy), cromatografía de líquidos de alta resolución (HPLC, High Performance Liquid Chromatography) y carbono orgánico total (TOC, Total Organic Carbon). Los resultados indicaron mayor eficiencia durante el proceso a condiciones de pH 6 e imposición de 10 mA cm-2, obteniendo una mineralización promedio del 69.4±5.6%, del contaminante a 60 minutos, mientras que la degradación del contaminante ocurrió durante los primeros 5 minutos del proceso.

Advanced oxidation processes: flowsheet options for bulk natural organic matter removal

2004 ◽  
Vol 4 (4) ◽  
pp. 113-119 ◽  
Author(s):  
C.A. Murray ◽  
S.A. Parsons
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Natural Organic Matter ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Oxidation Processes

Advanced oxidation processes have been reported to have the potential to remove natural organic matter from source waters. Of these Fenton's reagent, photo-Fenton's reagent and titanium dioxide photocatalysis are the three most promising processes. Compared to conventional coagulation/flocculation processes they have higher removal efficiencies in terms of both dissolved organic carbon and UV254 absorbance. Under optimum reaction conditions all three remove over 80% dissolved organic carbon and 0% UV254 absorbance. In addition the enhanced removal of natural organic matter leads to a corresponding reduction in the formation of disinfection by-products following chlorination of the treated water. Advanced oxidation processes give enhanced removal of organic species ranging from low to high molecular weight while coagulation/flocculation is inefficient at removing low molecular weight species. One additional benefit is all three processes produce less residuals compared to conventional coagulation, which is advantageous as the disposal of such residuals normally contributes a large proportion of the costs at water treatment works.

scholarly journals Electrochemical Hydrogen Peroxide Production in Acidic Medium Using a Tubular Photo-reactor: Application in Advanced Oxidation Processes

2017 ◽  
Vol 58 (3) ◽  
Author(s):  
Juan M. Peralta-Hernández ◽  
Luis A. Godínez
Keyword(s):  
Hydrogen Peroxide ◽  
Acidic Medium ◽  
High Performance ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Electrochemical Reactor ◽  
Coliform Bacteria ◽  
Carbon Cloth ◽  
Oxidation Processes ◽  
Electrochemical Advanced Oxidation Processes

<p>This paper describes the results obtained in the design and characterization of a tubular electrochemical reactor. The set-up was employed for on-site hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production in an acidic medium (pH 3) to promote three electrochemical advanced oxidation processes (EAOP): electro-Fenton (EF), photoelectro-Fenton (PEF) and photocatalysis treatment (PT). These processes were evaluated by their abilities to degrade a commercial dye, Orange-II (OGII), in solution using total organic carbon (TOC) removal and high performance liquid chromatography (HPLC). To have free solutions of iron in the EF and PEF systems, a Nafion<sup>TM</sup> membrane with dispersed iron was prepared. For use in photocatalysis, electrodes with a large superficial area were prepared by coating carbon cloth fiber supports with titanium dioxide (TiO<sub>2</sub>) using the electrophoretic (EP) method. In this work, wastewater samples with a large number of microorganisms (coliform bacteria) were treated with this new reactor design.</p>

scholarly journals Kinetics of photocatalytic removal of imidacloprid from water by advanced oxidation processes with respect to nanotechnology

2019 ◽  
Vol 17 (2) ◽  
pp. 254-265 ◽  
Author(s):  
A. Derbalah ◽  
M. Sunday ◽  
R. Chidya ◽  
W. Jadoon ◽  
H. Sakugawa
Keyword(s):  
Organic Carbon ◽  
Advanced Oxidation Processes ◽  
Catalyst Concentration ◽  
Irradiation Time ◽  
Formation Rate ◽  
Advanced Oxidation ◽  
Water Type ◽  
Oxidation Processes ◽  
Photocatalytic Removal ◽  
Kinetics Of

Abstract In this study, the kinetics of photocatalytic removal of imidacloprid, a systemic chloronicotinoid insecticide, from water using two advanced oxidation systems (ZnO(normal)/H2O2/artificial sunlight and ZnO(nano)/H2O2/artificial sunlight) were investigated. Moreover, the effects of pH, insecticide concentration, catalyst concentration, catalyst particle size, and water type on the photocatalytic removal of imidacloprid were evaluated. Furthermore, total mineralization of imidacloprid under these advanced oxidation systems was evaluated by monitoring the decreases in dissolved organic carbon (DOC) concentrations and formation rate of inorganic ions (Cl− and NO2−) with irradiation time using total organic carbon (TOC) analysis and ion chromatography to confirm the complete detoxification of imidacloprid in water. The degradation rate of imidacloprid was faster under the ZnO(nano)/H2O2/artificial sunlight system than the ZnO(normal)/artificial sunlight system in both pure and river water. The photocatalytic degradation of imidacloprid under both advanced oxidation systems was affected by pH, catalyst concentration, imidacloprid concentration, and water type. Almost complete mineralization of imidacloprid was only achieved in the ZnO(nano)/H2O2/artificial sunlight oxidation system. The photogeneration rate of hydroxyl radicals was higher under the ZnO(nano)/H2O2/artificial sunlight system than the ZnO(normal)/H2O2/artificial sunlight system. Advanced oxidation processes, particularly those using nanosized zinc oxide, can be regarded as an effective photocatalytic method for imidacloprid removal from water.

UV-induced photodegradation of oseltamivir (Tamiflu) in water

2011 ◽  
Vol 8 (2) ◽  
pp. 182 ◽  
Author(s):  
Alfred Y. C. Tong ◽  
Rhiannon Braund ◽  
Eng W. Tan ◽  
Louis A. Tremblay ◽  
Tristan Stringer ◽  
...  
Keyword(s):  
High Performance ◽  
Advanced Oxidation Processes ◽  
Treatment Options ◽  
Antiviral Drug ◽  
Advanced Oxidation ◽  
Degradation Process ◽  
Order Rate Constant ◽  
Sewage Water ◽  
Oxidation Processes ◽  
First Order

Environmental contextOseltamivir (Tamiflu) is widely used to prevent and treat influenza but conventional wastewater processes involving sedimentation and biotic oxidation do not appear to significantly remove it from sewage, leading to its discharge into the environment. A range of advanced oxidation processes (AOPs) involving photolysis of aqueous solutions of oseltamivir with UV alone, UV/H2O2 and UV/H2O2/FeII is demonstrated to lead to photodegradation of oseltamivir to products with no ecotoxicity observed. These AOPs may therefore offer potentially environmentally friendly sewage water treatment options. AbstractAqueous solutions of the antiviral drug oseltamivir phosphate (OSP, Tamiflu, (3R,4R,5S)-ethyl 4-acetamido-5-amino-3-(pentan-3-yloxy)cyclohex-1-enecarboxylate) were degraded using advanced oxidation processes (AOPs) involving photodegradation with UV alone, UV/H2O2 and UV/H2O2/FeII (photo-Fenton reaction). The photodecay of the parent OSP in all three cases followed first-order kinetics with respective rate constants of 0.21, 1.56 and 1.75 min–1 at 20°C in pH 7 phosphate-buffered Milli-Q water. The rate of UV/H2O2 photolysis in the presence of 2-methylpropan-2-ol was significantly slower with an approximate first-order rate constant of 0.13 min–1 suggesting the involvement of •OH in the degradation process. NMR spectroscopy, mass spectrometry and high-performance liquid chromatography (HPLC) with UV diode array detection were used to identify the crude photoproduct as the hydroxylated OSP derivative (3S,4R,5S)-ethyl 4-acetamido-5-amino-2-hydroxy-3-(pentan-3-yloxy)cyclohexanecarboxylate that occurs by an unknown mechanism. OSP and this crude photoproduct demonstrated no effect on the survival of Quinquelaophonte sp. over 96 h.

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