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International audience; Titanium-vanadium oxo-alkoxy (VTOA) nanoparticles with vanadium addition (V:Ti) between 0 and 20 mol% were prepared via sol-gel method in a chemical reactor with ultra-rapid micromixing. A control of the nucleation and growth process in the reactor permitted synthesis of size-selective V-TiO 2 nanoparticles, which were used for the nanocoatings deposition on glass beads. The activity of the prepared photocatalysts (after calcination at 450 °C) was studied by the degradation of methylene blue in aqueous solutions under UVA illumination. A steady decrease of the reaction rate was observed with an increase of the vanadium content. This effect was explained by the residual presence of non-crystallized oxide, which elimination requires further studies.

International audience; Over the past few decades, biotransformations of compounds with complicated and reinforced structures, especially some poorly biodegradable organic pollutants, have attracted extensive research attention. Benefiting from recently developed techniques of protein engineering, oxidoreductase industrial applications such as laccases, tyrosinases, and various oxygenases have been recognized as a promising alternative technique as compared with the conventional treatment processes of industrial textile effluents. However, the lack of long-term operational stability and reusability of the above-mentioned enzymes may limit their further large-scale industrialization. To overcome this, a novel biocatalyst was developed by immobilizing laccase from Trametes versicolor onto ultraporous gamma-alumina powders (laccase@UPA(γ)), followed by transferring it into a portable and easy-to-carry bioreactor for Remazol Brilliant Blue R (RBBR) dye biodegradation. The obtained results showed that the treatment capacity of laccase@UPA(γ) towards RBBR reached about 60 mg/g after 24 h of contact time at pH 5. These preliminary results highlight the potentials of bio-based inorganic materials in industrial wastewater treatment, which can broaden our understanding of their practical applications in the environmental field.

International audience; In a previous work in our team (Oualha et al., Chem Eng Trans, vol 73, 67-72 (2019)) it was shown that at large Reynold numbers (Re > 8000) a vapor phase appears by cavitation in T-mixer reactors used for chemical precipitation of nanoparticles. This phenomenon can affect dramatically the properties of the obtained nanoparticles. In the work of Oualha et al (2019), the apparent size (more precisely the hydrodynamic diameters) of vapor bubbles due to the cavitation, was in situ monitored in the reactor by using SLS (Static Light Scattering) and DLS (Dynamic Light Scattering) methods. A modeling was also given using Fluent software: calculated size population of bubble was provided. Unfortunately this population could not be directly compared to experimental data since the relationship between apparent and real size was unknown. In the present work, new DLS measurements using particles of calibrated sizes are presented to help us to interpret and comment our previous results on bubbles size distribution. They were obtained using a new apparatus designed and realized for the purpose of defining a method of true diameters measurement.

International audience; The development of thins layers with antimicrobial priorities has been a key factor for inhibiting the growth of microorganisms and preventing nosocomial infections. This research work focuses on the synthesis and characterization of thin layers of functional metal oxides based on ZnO nanoparticles for applications to surfaces and coatings on various supports (paints, coatings …). In our work we developped as antibacterial agents, nanoparticles of zinc oxide. The synthesis of nanoparticles is performed with sol-gel method, we obtained nanoparticles around 3 nm of diameter. The antibacterial activity has been studied on strains from the European pharmacopoeia; Staphylococcus aureus (ATCC 6538) and Escherichia Coli (ATCC 8739). The test consists in artificial contamination by inoculum of microorganisms. We developed specific methodology for thin layer antibacterial tests. Results show an inhibition of bacterial growth by reduction greater than 5 log 10 of the initial bacterial population.

International audience; Due to its unique supramolecular structure, cellulose is widely used as a template agent, ensuring an easy structuring of anatase TiO2 particles with subsequent release after the organics burning. This work is devoted to the synthesis of microcrystalline cellulose-TiO2 (MCC-TiO2) composite photocatalyst by preserving the intermediate organic-inorganic structures. A series of the MCC-TiO2 materials were prepared via solvothermal sol-gel method in n-decane and caproic acid solvents and characterized by X-ray diffraction, transmission electron microscopy, IR spectroscopy, 1 Н NMR and TG/DSC methods. The photocatalytic activity of the prepared materials was evaluated by the decomposition of formic acid in aqueous solutions. The composites failed to be formed in n-decane, while in caproic acid, acting as solvent and reagent, anatase TiO2 nanoparticles were formed onto the crystalline domains of cellulose, tightly fixed due to covalent Ti-O-C bonds. The materials formed in caproic acid showed a higher photocatalytic activity, explained by a complementarity of the organic and inorganic components. The specific activity (normalized on TiO2 mass) of best synthetized composite materials was almost twice higher than that of Aeroxide P25 TiO2 reference photocatalyst.