Progression in Photocatalytic Materials for Efficient Performance

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Effective heterogeneous electro-Fenton process for the degradation of a malodorous compound, indole using iron loaded alginate beads as a reusable catalyst

International audienceIn this work the characterization and the performance of iron immobilized in alginate beads (Fe-ABs) as catalyst for heterogeneous electro-Fenton (EF) treatment of a malodorous compound, indole, was investigated. Experimental results demonstrated that indole was effectively removed through the electro-Fenton process; while in the considered experimental conditions, the performances of EF were only slightly improved by the addition of UVA radiation. The most efficient operating conditions were achieved at pH 3.0 in the presence of 200 mg L−1 Fe-ABs catalyst (corresponding to an average iron concentration of 64 mg L−1) with a current density of 0.53 mA cm−2. Under these conditions, 60 min were sufficient to completely degrade 20 mg L−1 of indole, whose removal was found to obey the pseudo-first order model. In terms of organic carbon removal, about 90% mineralization yield was reached in the optimal conditions for 7 h heterogeneous electro-Fenton treatment time. UPLC–MS/MS analysis was applied to identify and follow the evolution of indole oxidation products. Five stable organics intermediates were observed and four of them were identified as dioxindole, isatin, oxindole and anthranilic acid. A reaction sequence was therefore proposed for indole degradation according to the detected products. Subsequent attack of these intermediates by OH radicals led to the formation of short chain acids such as succinic, acetic, oxamic and oxalic identified by ion-exclusion chromatograph

Incidence of Fusarium foot and root rot of cereals under conservation agriculture in north west Tunisia

Conservation agriculture, based on direct drilling for crop establishment, has emerged in Tunisia since 1999/2000 as an alternative to conventional agriculture based on conventional drilling. The main objective of this approach is to ensure yield stability from crops and replenishment of soil organic matter. Previous research has demonstrated increased risks from pathogens favoured by mulching. The impacts of direct drilling on yields, and Fusarium foot and root rot of durum wheat, oat and barley, were studied over three successive growing seasons (2009/10, 2010/11, 2011/12) in northwest Tunisia. Disease incidence was estimated by the recovery frequency of Fusarium spp. isolates from stem bases and roots of plants of the three cereals. In addition, disease severity was assessed by occurrence of whiteheads that senesced prematurely, and the browning intensity on durum wheat stem bases. Grain yields were recorded at the ripening stages. Fusarium culmorum and F. pseudograminearum were isolated from the three cereals, with F. culmorum being the dominant pathogen. Direct drilling increased the incidence (60%) of these pathogens on stem bases and roots during the warmer seasons of 2009/10 and 2010/11, but less infection (37%) compared to conventional drilling was observed in the wetter season of 2011/12. Direct drilling increased the percentage of whiteheads of durum wheat (73%), but did not affect disease severity, which was estimated by the discolouration on stem bases and grain yield

An Emerging Visible-Light Organic–Inorganic Hybrid Perovskite for Photocatalytic Applications

The development of visible-light active photocatalysts is a current challenge especially energy and environmental-related fields. Herein, methylammonium lead iodide perovskite (MAIPb) was chosen as the novel semiconductor material for its ability of absorbing visible-light. An easily reproducible and efficient method was employed to synthesize the as-mentioned material. The sample was characterized by various techniques and has been used as visible-light photocatalyst for degradation of two model pollutants: rhodamine B (RhB) and methylene-blue (MB). The photo-degradation of RhB was found to achieve about 65% after 180 min of treatment. Moreover, the efficiency was enhanced to 100% by assisting the process with a small amount of H2O2. The visible-light activity of the photocatalyst was attributed to its ability to absorb light as well as to enhance separation of photogenerated carriers. The main outcome of the present work is the investigation of a hybrid perovskite as photocatalyst for wastewater treatment

Valeur alimentaire des marcs de raisin. V. Comportement alimentaire et vitesse de transit chez le mouton

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Valeur alimentaire des marcs de raisin. IV. Effet de différents niveaux de concentré de complémentation sur la digestibilité chez le mouton de rations de marc traité ou non à la soude

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Valeur alimentaire des marcs de raisin. III. - Rôle des tanins condensés dans la faible valeur nutritive des marcs de raisin chez le mouton : effet d'une addition de polyéthylène glycol 4 000

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Crystal structure, Hirshfeld surface analysis and energy framework calculation of the first oxoanion salt containing 1,3-cyclohexanebis(methylammonium): [3-(azaniumylmethyl)cyclohexyl]methanaminium dinitrate

The title salt, C8H20N22+·2NO3−, was obtained by a reaction between 1,3-cyclohexanebis(methylamine) and nitric acid. The cyclohexane ring of the organic cation is in a chair conformation with the methylammonium substituents in the equatorial positions and the two terminal ammonium groups in a trans conformation. In the crystal, mixed cation–anion layers lying parallel to the (010) plane are formed through N—H...O hydrogen-bonding interactions; these layers are formed by infinite undulating chains running parallel to the [001] direction. The overall intermolecular interactions involved in the structure were quantified and fully described by Hirshfeld surface analysis. In addition, energy-framework calculations were used to analyse and visualize the three-dimensional topology of the crystal packing. The electrostatic energy framework is dominant over the dispersion energy framework