Nitrogen-containing organic compounds: Origins, toxicity and conditions of their photocatalytic mineralization over TiO2

Bamba, Drissa; Coulibaly, Mariame; Robert, Didier

doi:10.1016/j.scitotenv.2016.12.130

Cited by 48 publications

(20 citation statements)

References 198 publications

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“…The oxygen content in the brine also had a pronounced seasonal pattern, when it decreased in May -June due to eutrophication processes that were also the characteristic of other lakes (Bamba et al, 2017). By August, the oxygen content increased up to the maximum values; however, the range of variability was much pronounced in 2018 comparing to that in 2017.…”

Section: Discussionmentioning

confidence: 91%

“…Their ecosystems are very vulnerable to the changes in abiotic factors, which may lead to irreversible changes in the conditions historically prevailing in these reservoirs. Biota itself is an important factor in the stable functioning of the lacustrine-mud ecosystem, since the interactions of its key components determine the most important processes for the production and destruction of organic matter, the pharmacological properties of hydromineral resources, the toxicity of soils and brine at the events of eutrophication and accumulation of pollutants, including those of anthropogenic origin (Bamba et al, 2017;Berman and Chava, 1999). The resources of hypersaline lakes are intensively used in human economic activity, since the brine minerals serve as raw materials for chemical industry enterprises, the sediments are used for medicinal purposes in balneology, in the cosmetic and pharmaceutical industries, and the dominant species of brine shrimp (Artemia sp.)…”

Section: Translated By Dm Martynovamentioning

confidence: 99%

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Influence of hydrometeorological factors on the ecological state of the hypersaline lake Saki (Crimea) in 2017–2018

Rudneva¹,

Chaban²,

Golub³

et al. 2020

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In order to identify the influence of hydrometeorological conditions on the seasonal changes in the ecological state of the salt Lake Saki (Crimea), the dynamics of hydrochemical parameters of wa-ter (salinity, oxygen content, temperature, pH, Eh) and changes in the population of the brine shrimp Artemia salina L., as well as the proportion of hatching nauplii from cysts were studied in 2017 and 2018. A decrease in oxygen content and an increase in brine salinity in the summer were accompanied by an increase in air temperature and water temperature; the interannual differ-ences of these parameters were preconditioned by the hydrome-teorological peculiarities. Artemia cysts were found in the water column throughout the year; the nauplii appeared in February – March; the maximum abundance of all life stages of brine shrimp was noted in May. The proportion of hatching nauplii from cysts collected in the cold season was significantly higher than that in the warm season. The observed patterns are discussed as a pos-sible source for analyzing the transformation of hyperhaline eco-systems within the ongoing climate change and for developing the guidelines for the optimal commercial use of the mineral and biological resources of such ecosystems.

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Section: Discussionmentioning

confidence: 91%

Section: Translated By Dm Martynovamentioning

confidence: 99%

Influence of hydrometeorological factors on the ecological state of the hypersaline lake Saki (Crimea) in 2017–2018

Rudneva¹,

Chaban²,

Golub³

et al. 2020

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“…In this regard, from the application of a photocatalytic processes, it was recently suggested that the attack of HO • on the α-carbon atom of the nitrogen group in organic compounds leads to the formation of NH4+ through an amide intermediate followed by an additional hydrolysis (Bamba et al, 2017). It was reported that the direct attack of HO • on the nitrogen atom can produce NO3-, whereas the N 2 is generally produced through the photodegradation of the -N = N- bond; apparently, the mineralization of nitrogen strongly depends on the degree of initial oxidation of this element contained in the pollutant to be degraded (Bamba et al, 2017). In Figures S4C,D, it was observed that the interaction of main factors AB had a positive standardized effect on the reacted H 2 O 2 and MO decolourization, as the combined increase of the mentioned factors also increased the production of highly oxidizing species and favored the speed of the CWPO reaction.…”

Section: Resultsmentioning

confidence: 99%

CWPO Degradation of Methyl Orange at Circumneutral pH: Multi-Response Statistical Optimization, Main Intermediates and by-Products

et al. 2019

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The catalytic wet peroxide oxidation (CWPO) of the industrial azo-dye methyl orange (MO) activated by an Al/Fe-pillared clay catalyst was optimized by the Response-Surface Methodology (RSM). Three sequential sets of factorial 2k central composite experiments were required for the full optimization of the process; catalyst loading and stoichiometric dose of hydrogen peroxide were the experimental factors studied through different times of reaction by means of all, Dissolved Organic Carbon (DOC) removal, Total Nitrogen (TN) removal, reacted fraction of hydrogen peroxide, and decolorization as experimental responses to be maximized. The resulting single-response RSM optimums were combined in a multi-response Desirability function ruling out the differential effect of adsorption on the catalyst's surface by defining all responses per gram of clay catalyst. Former two statistical sets of experiments (DOE-1 and DOE-2) showed the CWPO degradation of MO to get favored at increasing both catalyst loading and time of reaction (up to 180 min). Afterwards, third final design of experiments (DOE-3) displayed 75% of DOC removal, 78% of TN removal, 97% of reacted H2O2, and 95% of decolorization by using a catalyst loading of 5.0 g/L of Al/Fe-PILC together with just 50% of the stoichiometric amount of H2O2. The multi-response optimum conditions based on the Desirability function showed excellent fitting explaining at least 99.3% of the optimal overall responses at 95% of confidence. A further analysis revealed that no one of the non-controllable variables under real conditions of industrial wastewater treatment (covariates): starting total organic carbon (TOC) (2.0–20 mg/L), temperature (5.0–25°C) or circumneutral pH (6.0–9.0), exhibited statistically significant effect (P > 0.05), suggesting the system to be almost insensitive against them within studied range of close to ambient conditions in the tropic. Finally, HPLC/PDA and GC/FID measurements identified phenol, cyclohexa-2,5-diene-1,4-dione, phenylamine, N-methylaniline and N,N-dimethylaniline in very low concentrations as main intermediates in the CWPO degradation of MO, which nevertheless disappeared over 90 min of treatment. Meanwhile, 4-aminobenzenesulfonic and oxalic acids were recorded as unique by-products at final time of reaction, but both of them fairly less toxic than the starting azo-dye.

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“…Therefore, it is necessary to examine the mineralization of metalaxyl. The photocatalytic mineralization of nitrogen containing organic compounds predominantly depends on the chemical nature of the organic pollutant, that is, the oxidation state and the position of nitrogen atoms in molecular chain [46,47]. It has been reported that a complete oxidation of nitrate ions does not occur during the mineralization of organic compounds containing N. In the mineralization, ammonium ion can also be generated [48,49].…”

Section: Mineralizationmentioning

confidence: 99%

Photocatalytic degradation of a typical agricultural chemical: metalaxyl in water using TiO2 under solar irradiation

et al. 2020

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The photodegradation and mineralization of the metalaxyl [methyl N-(2,6-dimethyl-phenyl)-N-(methoxyacetyl)-alaninate], which is a popular benzenoid fungicide, was conducted in the presence of TiO 2 photocatalyst under solar irradiation. An initial metalaxyl concentration of 50 ppm was completely degraded in presence of TiO 2 after 30 min irradiation, while no degradation was observed in absence of TiO 2 under solar irradiation. The effect of different parameters, such as amount of TiO 2 , initial pH, light intensity, reaction temperature and irradiation time, on the photocatalytic degradation of metalaxyl was evaluated. The drop of total organic carbon as a consequence of mineralization of metalaxyl was detected during the photocatalytic process. The kinetics of photocatalytic degradation followed a pseudo-first order law according to Langmuir-Hinshelwood model, and the rate constant was 0.105 min −1. Ammonium ion and CO 2 were speculated as the end-products after completing degradation of metalaxyl. The five types of intermediate products were identified by GC-MS during the decomposition of metalaxyl. In order to investigate the degradation pathway of metalaxyl, the point charge and frontier electron density at each atom on the molecule were determined by using MOPAC stimulation. The degradation mechanism was proposed from the identified intermediates. The solar photocatalytic degradation method can become an effective technique for the treatment of metalaxyl-polluted water. Keywords Metalaxyl • Photodegradation • TiO 2 photocatalyst • Point charge • Frontier electron density • GC-MS All experiments were conducted at Mie University. Any opinions, findings, conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the view of the supporting organizations.

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Nitrogen-containing organic compounds: Origins, toxicity and conditions of their photocatalytic mineralization over TiO2

Cited by 48 publications

References 198 publications

Influence of hydrometeorological factors on the ecological state of the hypersaline lake Saki (Crimea) in 2017–2018

Influence of hydrometeorological factors on the ecological state of the hypersaline lake Saki (Crimea) in 2017–2018

CWPO Degradation of Methyl Orange at Circumneutral pH: Multi-Response Statistical Optimization, Main Intermediates and by-Products

Photocatalytic degradation of a typical agricultural chemical: metalaxyl in water using TiO2 under solar irradiation

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