Quantum efficiencies of the photo-Fenton degradation of atrazine in water

2012 ◽  
Vol 66 (10) ◽  
pp. 2209-2216 ◽  
Author(s):  
T. B. Benzaquén ◽  
M. A. Isla ◽  
O. M. Alfano

An experimental work in a well-stirred batch recycling reactor for the photo-Fenton degradation of atrazine in water is presented. A study of the quantum efficiency is performed to assess the effectiveness of the photo-Fenton process on the atrazine degradation and total organic carbon (TOC) mineralization. Apparent and absolute quantum efficiencies of degradation and mineralization of an atrazine-based commercial herbicide are determined under different experimental conditions. Higher apparent efficiencies were found for both atrazine degradation and TOC mineralization when the ferric ion and hydrogen peroxide concentrations are increased. Because of the well known stability of the triazine ring, atrazine was not completely mineralized by the photo-Fenton process. However, a TOC reduction of 40% was achieved, being 62.5% of the maximum value that can be reached.

2017 ◽  
Vol 23 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Gamze Dalgic ◽  
Ilter Turkdogan ◽  
Kaan Yetilmezsoy ◽  
Emel Kocak

The study investigated the pretreatment of real paracetamol (PCT) wastewater of a pharmaceutical industry by Fenton process. At the best experimental conditions (COD/H2O2 = 1/1, Fe+2/H2O2 = 1/70, settling method:centrifuging, pH 6 at settling step), 92.7, 92.7, 95.5, 99.1, 99.9 and 99.4% of chemical oxygen demand (COD), total organic carbon (TOC), 5-day biological oxygen demand (BOD5), PCT, para-amino phenol (PAP) and aniline were removed, respectively. Changes in the concentrations of these parameters were also investigated for both oxidation and settling steps of Fenton process. It was found that COD and TOC were removed at the settling step (precipitation) whereas PCT, PAP and aniline were removed at the oxidation step. Mass balance calculations were also studied to show the mass distributions of COD in different phases (gas + foam, effluent and sludge). Fenton process was found as an effective method for the pretreatment of real PCT wastewater for discharging in a determined collective treatment plant.


2018 ◽  
Vol 35 (1) ◽  
pp. 25
Author(s):  
Janaina Conrado Lyra Da Fonseca ◽  
Raquel Fernandes Pupo Nogueira ◽  
Mary Rosa Rodrigues De Marchi

Laboratories consume great amounts of hazardous chemicals substances and consequently generate wastewater containing them, for example formaldehyde. This substance is widely utilized to preserve biological samples generating many liters of this residue every year. The present work proposes the use of the photo-Fenton process to treat formaldehyde wastewater using sunlight irradiation. Some aspects were investigated such as the iron source, sample and hydrogen peroxide concentration and also the use of stirred systems. The use of ferrioxalate (0.5 mmol L-1) improved the efficiency of the process in relation to the use of iron nitrate, while at least 1.0 mol L-1 H2O2 is necessary to treat the sample of the 500 mg C L-1. Under these conditions, every formaldehyde detectable was degradeted and 89% of the dissolved organic carbon was removed in two hours of exposure to sunlight. These results are satisfaction considerate for São Paulo State Environmental Agency.


2010 ◽  
Vol 35 (1) ◽  
pp. 25-33
Author(s):  
Janaína Conrado L. Fonseca ◽  
Raquel F. Pupo Nogueira ◽  
Mary Rosa Rodrigues Marchi

Laboratories consume great amounts of hazardous chemicals substances and consequently generate wastewater containing them, for example formaldehyde. This substance is widely utilized to preserve biological samples generating many liters of this residue every year. The present work proposes the use of the photo-Fenton process to treat formaldehyde wastewater using sunlight irradiation. Some aspects were investigated such as the iron source, sample and hydrogen peroxide concentration and also the use of stirred systems. The use of ferrioxalate (0.5 mmol L-1) improved the efficiency of the process in relation to the use of iron nitrate, while at least 1.0 mol L-1 H2O2 is necessary to treat the sample of the 500 mg C L-1. Under these conditions, every formaldehyde detectable was degradeted and 89% of the dissolved organic carbon was removed in two hours of exposure to sunlight. These results are satisfaction considerate for São Paulo State Environmental Agency.


2010 ◽  
Vol 9 (3) ◽  
pp. 351-360 ◽  
Author(s):  
Abdelnaser Omran ◽  
Hamidi Abdul Aziz ◽  
Marniyanti Mamat Noor

Author(s):  
Vanessa Ribeiro Urbano ◽  
Milena Guedes Maniero ◽  
José Roberto Guimarães ◽  
Luis J. del Valle ◽  
Montserrat Pérez-Moya

Sulfaquinoxaline (SQX) has been detected in environmental water samples, where its side effects are still unknown. To the best of our knowledge, its oxidation by Fenton and photo-Fenton processes has not been previously reported. In this study, SQX oxidation, mineralization, and toxicity (Escherichia coli and Staphylococcus aureus bacteria) were evaluated at two different setups: laboratory bench (2 L) and pilot plant (15 L). The experimental design was used to assess the influence of the presence or absence of radiation source, as well as different H2O2 concentrations (94.1 to 261.9 mg L−1). The experimental conditions of both setups were: SQX = 25 mg L−1, Fe(II) = 10 mg L−1, pH 2.8 ± 0.1. Fenton and photo-Fenton were suitable for SQX oxidation and experiments resulted in higher SQX mineralization than reported in the literature. For both setups, the best process was the photo-Fenton (178.0 mg L−1 H2O2), for which over 90% of SQX was removed, over 50% mineralization, and bacterial growth inhibition less than 13%. In both set-ups, the presence or absence of radiation was equally important for sulfaquinoxaline oxidation; however, the degradation rates at the pilot plant were between two to four times higher than the obtained at the laboratory bench.


Author(s):  
Luciana Igarashi-Mafra ◽  
Edmilson César Bortoletto ◽  
Maria Angelica Simões Dornella Barros ◽  
Amanda Cristina Alfredo Contrucci Sorbo ◽  
Naiara Aguiar Galliani ◽  
...  

Effluents from radiographic X-ray film developing processes feature a high contaminant load (COD about 70000 mg/L and total phenols concentration about 16956 mg/L). Photo-Fenton's are potentially useful oxidation processes for destroying toxic organic compounds in water. In these reactions, hydrogen peroxide is combined with ferrous or ferric iron in the presence of light to generate hydroxyl radicals (·OH). The photo-Fenton process was explored as a photochemical treatment to degrade wastewater from radiographic X-ray film developing processes coming from odontologic clinics. A response surface methodology was applied to optimize the photo-Fenton oxidation process conditions using total phenol removal as the target parameter to be optimized, and the reagent concentrations, as related to the initial concentration of organic matter in the effluent, and time and pH as the control factors to be optimized. The best results in terms of maximal total phenol removal and economic process were achieved when wastewater samples were treated at pH 5 in the presence of hydrogen peroxide and iron in the ratios [total phenols]:[H2O2] 1:3 w/w and [Fe2+]:[H2O2] 1:18 w/w and time 1 h.


2015 ◽  
Vol 73 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Eric da Cruz Severo ◽  
Chayene Gonçalves Anchieta ◽  
Vitória Segabinazzi Foletto ◽  
Raquel Cristine Kuhn ◽  
Gabriela Carvalho Collazzo ◽  
...  

FeWO4 particles were synthesized by a simple, rapid and facile microwave technique and their catalytic properties in heterogeneous photo-Fenton reaction were evaluated. This material was employed in the degradation of Amaranth azo dye. Individual and interactive effects of operational parameters such as pH, dye concentration and H2O2 dosage on the decolorization efficiency of Amaranth dye were evaluated by 23 central composite design. According to characterization techniques, a porous material and a well-crystallized phase of FeWO4 oxide were obtained. Regarding the photo-Fenton reaction assays, up to 97% color and 58% organic carbon removal were achieved in the best experimental conditions. In addition, the photo-Fenton process maintained treatment efficiency over five catalyst reuse cycles to indicate the durability of the FeWO4 catalyst. In summary, the results reveal that the synthesized FeWO4 material is a promising catalyst for wastewater treatment by heterogeneous photo-Fenton process.


1999 ◽  
Vol 40 (1) ◽  
pp. 183-190 ◽  
Author(s):  
N. H. Ince ◽  
G. Tezcanlı

Treatability of textile dye-bath effluents by advanced oxidation with Fenton and Fenton-like reagents (FeII/H2O2 and FeIII/H2O2), in the presence and absence of UV light was investigated, using a reactive azo-dye (Procion Red HE7B), and typical dye bath constituents. Under the experimental conditions employed, it was found that with 20 min UV irradiation, complete color removal and 79% total organic carbon degradation is possible, when the system is operated at pH=3, and with a H2O2/Fe(II) molar ratio of 20:1. The increased dissolved solids content of the treated solution implies the necessity of an appropriate membrane system to make the effluent reusable in the dye/wash processes.


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