ZIF-8 materials as heterogeneous Fenton-like catalysts for degradation of pollutants in water

Zeolitic imidazolate frameworks (ZIFs) is a subclass of metalorganic frameworks (MOFs) formed by inorganic connectors and imidazolate organic linkers, topologically isomorphic with zeolites. Compared with other conventional inorganic porous materials, they have potential application in gas storage, adsorption separation and catalysis. Water pollution has become a worldwide issue, and sustainable processes are need. Fenton-type reaction is considered a promising, economical, sustainable method and that can be used to eliminate toxic and harmful substances in water, such as Tartrazine. Zeolite imidazole framework- 8-modified with different metal ratios was successfully synthesized to activate the hydrogen peroxide for the degradation of Tartrazine in open air by the Fenton-type reaction. Furthermore, the catalysts were characterized in order to understanding the catalytic activity's behavior of the materials. ZIF-8 could be regenerated easily and the reusability could be well maintained for at least three runs.We thank the Fundação para a Ciência e Tecnologia for financial support through Centre of Chemistry (UID/QUI/0686/2020) and BioTecNorte (operation NORTE-01-0145-FEDER-000004).info:eu-repo/semantics/publishedVersio

Copper-impregnated on natural material as promising catalysts for the wet hydrogen peroxide catalytic oxidation of Methyl Green

Promising catalyst of cooper impregnated on natural material (CT) synthesized via wet impregnation method, in order to enhance the catalytic wet peroxide oxidation during the degradation of organic matter in a batch reactor under mild conditions. Three different percentages of copper metal (2.5, 5 and 7.5 %) incorporated into CT material which are referred as follows 2.5% Cu-CT, 5% Cu-CT and 7.5% Cu-CT were investigated in the oxidation catalytic of methyl green (MG) dye. The chemical composition, the morphology and the structure of raw CT and all prepared samples, were investigated by X-ray fluorescence, Fourier transform infrared spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) to get a better understand concerning the catalytic activity behavior of Cu-CT catalyst. Different variable examined the catalytic activity of the samples obtained such as initial concentrations of dye, copper (Cu) loading, temperature and H2O2 effect was investigated to enhance the MG conversion. CWPO experiments showed that 2.5% Cu-CT catalysts have the maximum catalytic activity during the degradation of MG dye. The presence of copper on CT support ameliorates the hydroxyl radicals in the reaction medium after the contact with H2O2 thus enhanced the catalytic conversion of the CT pristine. The optimum conditions showing an important catalytic conversion of MG dye (95 %) at 2.5% of copper loading, 139.10-3 mol.L-1 H2O2, temperature of 40 °C and at pH 6.0 during  30 min as a reaction time. 

Optimization of CWPO for the Crystal violet and Methyl orange dyes degradation in the presence of copper-impregnated Moroccan clay catalysts

: Effectively removing textile dyes from wastewater is a challenging task that requires attention. This study explored the potential of copper-impregnated Moroccan clay (Cu@MC) as a catalyst to degrade the synthetic dyes Crystal Violet (CV) and Methyl Orange (MeO) from simulated wastewater using the catalytic wet peroxide oxidation (CWPO) technique. The study aimed to evaluate the effectiveness of Moroccan natural resources impregnated with a noble metal to facilitate the degradation process. To characterize the main surface functions of Cu@MC, several techniques were used, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled to energy-dispersive X-rays (EDX), X-ray diffraction (XRD), and BET. Box Behnken's response surface methodology was used to optimize CWPO conditions, including catalyst dose, dye concentration, and hydrogen peroxide. The proposed models were significant, according to statistical analysis of variance (ANOVA). The results of the Box Behnken design showed the highest removal efficiencies of 99.72% and 29.80% of CV and MeO, respectively. This result was achieved under optimum conditions of 0.75 g L⁻¹ catalyst dose, 20 mg L⁻¹ dye concentration, at a hydrogen peroxide concentration of 6 mmol L⁻¹. Overall, the study revealed that the Cu@MC catalyst has a high potential for effectively removing textile dyes from wastewater using the CWPO technique. The study highlights a promising strategy for developing effective and efficient wastewater treatment methods

The Co-Existence of Rheumatoid Arthritis and Systemic Lupus Erythematosus Biomarkers: Is It Rhupus?

Background: Rhupus is a rare clinical condition where rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) overlap and is characterized by the presence of erosive arthritis with symptoms and signs of SLE. This study aims to investigate the prevalence of anti-CCP antibodies in SLE patients from CHU BLIDA (Immunology unit) and its association with anti-DNA and Anti Sm, in order to make a diagnosis of rhupus among our patients. Methods: Our retrospective study included 96 patients fulfilling the American College of Rheumatology (ACR) classification criteria for lupus. anti-CCP antibodies, anti-Sm were analyzed by  ELISA, anti-DNA antibodies were determined by both IFI on Crithidia luciliae substrate and  ELISA. The FR by Laser Nephelemetry. Inclusion criteria are the presence of at least one immunological marker of LES with anti-CCP. The sex ratio F / H is equal to 13/1, where the average age is 37 years. Results: Anti-CCP was found in 14 patients  (14.6% ), 56.25% and 39.59%  had positive anti-DNA and antiSm respectively; rheumatoid factors (RF) were positive in 27.08% of cases; anti-CCP / FR combination was found in 7.3% of cases. Besides, the combination of anti-CCP and anti-DNA was found in 12.5%. These two autoantibodies were simultaneously absent in 49.92% of cases. Arthritis was found in 80 patients. Our results concerning the prevalence of immunological and clinical markers of RA such as anti-CCP, RF and arthritis in our lupus patients corroborate with those of the literature. Conclusion: Based on the presence of shared clinical features of RA and SLE along with the presence of anti-DNA and anti-CCP antibodies in our patients, our findings strongly support the contention that rhupus is a true overlap between RA and SLE. Despite being a rare entity, it is important to know the clinical and humoral elements that allow its early diagnosis, making it easier to start treatment in a timely manner and reduce its possible complications

Characterization of Bubble Shapes in Non‐Newtonian Fluids by Parametric Equations

Based on experiments with single air bubbles rising in stagnant non-Newtonian fluids, an innovative model containing the aspect ratio (E) and two parameters (alpha, beta) was proposed and proved to be capable of characterizing the bubble shape from spherical/ellipsoidal to prolate/oblate-tear with good accuracy. Several impacts on bubble deformation were investigated, involving the rheological properties of the fluids and different forces exerted on the bubble, which were quantified by multiple dimensionless numbers (e.g., Reynolds, Eotvos, and Deborah number). Within a wide range, the empirical correlations were obtained for parameter beta, and between alpha and beta. Together with the shape model, a complete system was set up for bubble shape characterization and prediction that will provide new ideas for future studies on bubble hydrodynamics

The metal elements traces dregs with the unstable fraction of the sediment of Sebou which risk?

In forms dissolved and/or fixed at the particles the metal elements traces can accumulate in the sedimentary zones and constitute important stocks of pollutants. These contaminants can be remaining in the dissolved phase and become biodisponible under the effect of the physicochemical conditions and could act as a long-term source of pollution. To understand the mobility and the reactivity of these stocks is an important issue for the management of the quality of the hydrosystèmes. The exchangeable or unstable fraction of the sediment corresponds to the metal ions being adsorbed on the surface of the particles constituting the sediment (clays, oxide iron…), or mobility and the biodisponibility are high in this fraction because of the weak electrostatic interactions. The goal of this study and to characterize the sediments of Sebou and Fès Rivers and to evaluate the risk of toxicity of the elements metal traces related to the particulate phase by the method of spared digestion. Metals in these fractions are assumed to be more available than metals associated with residual fractions. The results obtained show a strong mobilization of the elements related to the unstable fraction which reaches 100% for Pb and 70% for Cr. The sediments are composed of two mineralogical phases and they are also very rich in organic matter

L'effluent des huileries d'olive, traitement par adsorption et par oxydation catalytique

L'essor de l'industrie agro-alimentaire au Maroc entraîne des problèmes liés aux rejets gazeux, solides et liquides. La quantité moyenne annuelle des eaux de rejet des huileries, s'élève pour le Maroc à 150 000 à 200 000 m3/an. Ces rejets sont très chargés en matières organiques et en polyphenols, la DCO atteint parfois 600 g/l. Ils sont acides et contiennent beaucoup de sel, d'où leur grande agressivité vis à vis des égouts, des eaux et des sols. Il faut donc traiter ces eaux usées avant évacuation. Des méthodes de traitement existent, l'évaporation libre par la seule énergie solaire étant la plus utilisée dans la région de Fès. Nous en proposons deux : • L'adsorption sur différents matériaux solides, en l'occurrence deux argiles locales et le charbon actif pour comparaison. • L'oxydation catalytique par le peroxyde d'hydrogène, en milieu aqueux dilué. La 1re méthode conduit à des abattements de DCO proches de 60 % et de teneur en polyphenols avoisinant les 100 %, avec le charbon actif et l'argile jaune. La 2e méthodes ne s'applique que dans le domaine des concentrations faibles. Elle conduit également à une disparition presque totale des polyphenols et un abattement moyen de la DCO, probablement à cause des conditions douces de l'oxydation. L'élimination des polyphenols offre diverses possibilités. Les deux méthodes, chacune dans son domaine d'application, pourraient être complétées par l'evaporation, les traitements biologiques ou autres

Surface reconstruction of Pt-Sn nanoparticles supported on Al2O3 in the presence of carbon monoxide

SSCI-VIDE+ING+DBIInternational audiencePt-Sn particle

Heats of adsorption of linear CO species on the Pt sites of a 1.2% Pt-2.7% Sn/Al2O3 catalyst before and after reconstruction and ageing processes

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Adsorption Study for the Removal of Nitrate from Water Using Local Clay

Our research aimed at the removal of nitrate ions through adsorption by local clay. A series of batch experiments were conducted to examine the effects of contact time, adsorbent characteristics, initial concentration of nitrate, pH of the solution, concentration, and granulometry of adsorbent. Adsorption isotherms studies indicated that local clay satisfies Freundlich’s model. The rate of reaction follows pseudo-second-order kinetics. Local clay successfully adsorbs nitrates at pH acid. The adsorption capacity under optimal conditions was found to be 5.1 mg/g. The adsorption yield increases with adsorbent dose and decrease with initial concentration of nitrate. The local clay was characterized by the X-ray fluorescence method (XRF), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), scanning electronics microscopy (SEM), and measurement of specific surface area (BET). The results of the study indicated that local clay is useful materials for the removal of nitrates from aqueous solutions which can be used in water treatment without any chemical modification