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Degradation and Mineralization Study of Promecarb by Electro Fenton Process
Hayet Bakhti,
Najib Ben Hamida,
Didier Hauchard
Issue:
Volume 10, Issue 2, June 2022
Pages:
15-22
Received:
29 March 2022
Accepted:
14 April 2022
Published:
12 May 2022
Abstract: Organic substances as pesticides, especially aromatic compounds are a major environmental concern. In the present work, solutions of Promecarb or 3-isopropyl-5-methylphenyl-N-methylcarbamate of pH = 3 have been degraded by electro Fenton process, using a volumic electrochemical reactor filled with carbon graphite. Effects of nature of material of cathode, initial concentration of insecticide and applied current on the kinetics of oxidative degradation and mineralization efficiency have been investigated. Kinetic analysis showed that the oxidation of Promecarb by hydroxyl radicals follows a reaction kinetic of pseudo first order. The absolute rate constant for Promecarb oxidation by hydroxyl radicals was determined as 10.88 × 109 L mol-1 s-1 by competitive kinetics method and benzoic acid was used as reference compound. Mineralization of this pesticide by hydroxyl radicals consists in its transformation to mineral products. The evolution of the mineralization during Promecarb treatment by electro Fenton process was followed by analysis of Total Organic Carbon TOC. Thus, after 3 hours of electrolysis and at I = 800 mA, more than 50% of the organic carbon present in the solution is mineralized. Several degradation products were formed during its electro Fenton treatment. These intermediates were identified using High Performance Liquid Chromatography HPLC, Ionic Chromatography IC and Liquid Chromatography - Mass Spectrometry LC-MS. Based on identification of aromatic intermediates and carboxylic acids, a plausible Promecarb mineralization pathway is proposed. Also, we realized the measurement of the Biochemical Oxygen Demand BOD5 of insecticide solution after treatment by electro Fenton process, to evaluate its biodegradability.
Abstract: Organic substances as pesticides, especially aromatic compounds are a major environmental concern. In the present work, solutions of Promecarb or 3-isopropyl-5-methylphenyl-N-methylcarbamate of pH = 3 have been degraded by electro Fenton process, using a volumic electrochemical reactor filled with carbon graphite. Effects of nature of material of c...
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Comparison of Polycyclic Aromatic Hydrocarbons, Pahs Concentration Levels in Types of Beans and Maize from Markets in South East Nigeria
Ifeoma Maryrose Odika,
Chuma Okoye,
Njideka Veronica Nwankwo,
Uche Virginia Okpala,
Cecilia Aduaka,
Nneka Onyirioha
Issue:
Volume 10, Issue 2, June 2022
Pages:
23-28
Received:
14 March 2022
Accepted:
14 April 2022
Published:
12 May 2022
Abstract: Polycyclic aromatic hydrocarbons, PAHs are carcinogenic, mutagenic and persistent organic compounds commonly generated from incomplete combustion of organic matters. Beans, Phaseolus vulgaris and maize, Zea mays form part of staple foods commonly consumed and are highly rich in protein and carbohydrate respectively. This study compared the concentration levels of the sixteen priority PAHs in different types of beans (Potasikum, white iron, brown iron, Gausau and Nija red) and maize (white, yellow and pop corn) obtained from various markets in south east Nigeria. The purchased beans and maize samples were picked, ground and extraction was by sonication with a solvent mixture of dichloromethane and hexane in the ratio of 3:1. The determination of PAHs was by gas chromatography coupled with flame ionization detector, GC-FID. The result showed that the PAHs concentration levels (× 10-2 µg/kg) of lower molecular weight PAHs, LMW detected in the analyzed beans samples ranged from 8.842±4.743 to 12.590±8.068 in white iron beans and brown iron beans respectively with percentages of 41.09% and 44.90% and 5.998±4.725 to 9.385±11.339 in pop and white corn respectively at 25.58% and 34.46%. While the high molecular weight, HMW PAHs concentration levels (× 10-2 µg/kg) varied from 12.673±5.554 in white iron beans to 16.998±3.129 in Nija red beans at 58.88% and 63.95% and from 17.84±11.768 in pop maize to 18.153±10.421 in yellow maize at 74.83% and 67.43% respectively. The probable carcinogenic PAH8 concentrations detected varied from (8.875±2.725 to 11.796±3.018) × 10-2 µg/kg in white iron beans and brown iron beans respectively and from (10.82±6.183 to 13.573±8.789) × 10-2 µg/kg in pop and yellow maize respectively.. Diagnostic ratio calculated showed fuel combustion to be the main source of emission. The sixteen priority PAHs were detected in all the analyzed samples at a very low concentration levels, lower than the permissible limit of 1.0 µg/kg established by EFSA for cereals and cereal based products. Hence these (PAHs) can at a long time accumulation in the body be very harmful. There is need to establish a permissible limit of PAHs in beans and other legume grains by either European Food Safety Authority, EFSA or other regulatory bodies.
Abstract: Polycyclic aromatic hydrocarbons, PAHs are carcinogenic, mutagenic and persistent organic compounds commonly generated from incomplete combustion of organic matters. Beans, Phaseolus vulgaris and maize, Zea mays form part of staple foods commonly consumed and are highly rich in protein and carbohydrate respectively. This study compared the concentr...
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Study on Mechanism and Application of High Concentrations of Nitrite-Induced Specific Color Fading
Issue:
Volume 10, Issue 2, June 2022
Pages:
29-39
Received:
16 May 2022
Accepted:
6 June 2022
Published:
14 June 2022
Abstract: Nitrite and edible salt are easy to confuse for their similar appearance and taste, thus possibly causing nitrite poisoning. Therefore, it is particularly crucial to figure out how to screen high concentrations of nitrite, how to discriminate NaNO2 and NaCl, and how to accurately quantify high concentrations of nitrite. In this study, the phenomenon of high concentrations of nitrite fading to orange-yellow color in colorimetric solution of naphthalene ethylenediamine hydrochloride was studied and accurately quantified by dilution colorimetry. It is to prevent false negative detection while NaCl presented no such phenomenon. Through spectrophotometry, high-performance liquid chromatography, and liquid mass spectrometry, we discovered that the principle of high concentrations of nitrite fading to orange-yellow after colorimetry was that high concentrations of nitrite nitrosated azo compounds and naphthalene ethylenediamine hydrochloride in hydrochloric acid medium. This principle can make the solution appear orange-yellow while had almost no matrix interference and this demonstrates no difference in food and water. We thus argue that this principle can be used for the screening of high concentrations of nitrite, and discriminating NaNO2 and NaCl to prevent poisoning events caused by misuses. In this sense, we believe the principle in question has a high applying value and is worth promoting. It can be made into a commercial hydrochloric acid acidified naphthylethylenediamine hydrochloride solution for further commercialized applications.
Abstract: Nitrite and edible salt are easy to confuse for their similar appearance and taste, thus possibly causing nitrite poisoning. Therefore, it is particularly crucial to figure out how to screen high concentrations of nitrite, how to discriminate NaNO2 and NaCl, and how to accurately quantify high concentrations of nitrite. In this study, the phenomeno...
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