Laboratoire Réactions et Génie des Procédés

A wide-range experimental and theoretical investigation of ammonia gas-phase oxidation is performed, and a predictive, detailed kinetic model is developed.

Hydrogels are everyday materials characterized by their remarkable properties, of bridging the gap between liquid and solid states. While most hydrogels are traditionally formed from polymers, biomolecules can also undergo gelation, as seen with proteins (e.g., collagen), enabling numerous applications. Peptide-based low-molecular-weight hydrogels (LMWHs), composed of amino acids, have emerged as innovative materials with a broad range of biomedical and biotechnological applications, gaining commercial interest in the 2010s. However, natural peptides composed solely of proteinogenic amino acids present several drawbacks, requiring structural or chemical modifications to enhance their performance. Additionally, multicomponent approaches, which involve combining multiple compounds to form hydrogels, have recently gained prominence as a promising strategy for developing more versatile and efficient systems. In this context, we explore emerging hybrid molecules, i.e., peptides functionalized with DNA bases (i.e., adenine, thymine, guanine, and cytosine), known as nucleopeptides. These compounds have shown encouraging results, yet much remains to be explored to unlock their full potential. In this study, we present a novel series of six (nucleo)-peptides derived from two distinct peptide sequences, Phe-Glu-Phe-Glu and Phe-Lys-Phe-Lys, negatively and positively charged at physiological pH, respectively, making them complementary in terms of electrostatic interactions. These peptides are functionalized with one of the four DNA nucleobases, introduced via a peptide nucleic acid (PNA) moiety. Thus, through a comprehensive multiscale systematic study, we report herein on the impact of charge complementarity and/or nucleobase-pair complementarity on the mechanical and physicochemical properties of the resulting multicomponent hydrogels (including gelation time, sol-gel transition temperature, stiffness, resistance to external stress, fibrillar network morphology, etc.). Then, the results highlight the undeniable potential of this approach, demonstrating that careful selection of components allows the fine-tuning of hydrogel properties. Interestingly, our findings reveal unexpected behaviors, underscoring the complexity of these bioinspired hybrid multicomponent systems while reinforcing their potential for the development of high-performance and innovative supramolecular hydrogels.

The reactivity of the zinc(+2) salt allows tuning of the size and catalytic activity of ZIF-8 crystals.

This review focuses on the radiosensitization strategies that use high-Z nanoparticles. It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy. Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist. In particular, we described and evaluated the influence of X-rays energy spectra using a numerical analysis. We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy. Pointing out the critical parameters of high-Z nanoparticles radiosensitization, this review is expected to contribute to a larger preclinical and clinical development.

There is increasing public concern regarding the fate of antibiotic resistance genes (ARGs) during wastewater treatment, their persistence during the treatment process and their potential impacts on the receiving water bodies. In this study, we used quantitative PCR (qPCR) to determine the abundance of nine ARGs and a class 1 integron associated integrase gene in 16 wastewater treatment plant (WWTP) effluents from ten different European countries. In order to assess the impact on the receiving water bodies, gene abundances in the latter were also analysed. Six out of the nine ARGs analysed were detected in all effluent and river water samples. Among the quantified genes, intI1 and sul1 were the most abundant. Our results demonstrate that European WWTP contribute to the enrichment of the resistome in the receiving water bodies with the particular impact being dependent on the effluent load and local hydrological conditions. The ARGs concentrations in WWTP effluents were found to be inversely correlated to the number of implemented biological treatment steps, indicating a possible option for WWTP management. Furthermore, this study has identified blaOXA-58 as a possible resistance gene for future studies investigating the impact of WWTPs on their receiving water.

Phytomining technology employs hyperaccumulator plants to take up metal in harvestable plant biomass. Harvesting, drying and incineration of the biomass generates a high-grade bio-ore. We propose that "agromining" (a variant of phytomining) could provide local communities with an alternative type of agriculture on degraded lands; farming not for food crops, but for metals such as nickel (Ni). However, two decades after its inception and numerous successful experiments, commercial phytomining has not yet become a reality. To build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide "real-life" evidence for profitability.

The objective of this paper is on the one hand to study the effect of heat processing (30 to 130°C for 2 h) on the stability and antioxidant activity of six flavonoids (rutin, naringin, eriodictyol, mesquitol, luteolin, and luteolin 7-O glucoside), and on the other hand to establish the relation structure–activity–stability of these compounds. The dependency on temperature of the six kinetics was well described by the Arrhenius law and the main parameters provided by this model are determined and compared in this paper. Activation energies found were 107.3 kJ/mol for rutin, 100.6 for naringin, 33.3 for mesquitol, 68.2 for eriodictyol, 51.4 for luteolin, and 120 for luteolin 7-O-glucoside. The data collected showed that glycosylated flavonoids are more resistant than aglycon flavonoids to heat treatment. Moreover, it was also observed that despite the total degradation of some flavonoids, the treated solutions still have an antioxidant activity. Practical application Flavonoids are mainly consumed in processed foods. Thus, flavonoids often undergo heat processing. Knowing the thermal stability and the evolution of their antioxidant activity are particularly relevant in the field of food processing. The results of this study allow information to be collected on the relationship between heat stability-flavonoid structure and antioxidant activity. This information will be useful for the formulation of new food products or for the design of new food processes.

Ingenious cellulose-based materials were applied in smart piezoelectric and triboelectric nanogenerators for highly efficient energy harvesting.

Summary Biochar, the solid product of biomass pyrolysis, can be used as a soil amendment to stabilize metals in contaminated soils. The effects of biochar on the mobility of metals in soils are, however, poorly understood. To identify the predominant processes, we focused on (i) a possible kinetic limitation by transport in biochar particles, (ii) the evolution of biochar mineral phases and (iii) the effect of biochar on soil pH . Batch experiments were conducted to measure the sorption kinetics of copper ( Cu ), cadmium ( Cd ) and nickel ( Ni ) and the sorption‐desorption isotherms for lead ( Pb ), Cu , Cd , zinc ( Zn ) and Ni in a wood‐derived biochar. Sorption data were then compared with extraction test results using biochar with one acidic and one basic soil contaminated by Zn , Cd and Pb . Kinetic results showed that biochar particle sizes controlled metal sorption rate despite a similar specific surface area, which indicated a limitation by intra‐particle diffusion. Isotherms showed a partially reversible sorption to biochar following the order Pb > Cu > Cd ≥ Zn > Ni , which we explained primarily by the (co)precipitation of metals or their adsorption on specific biochar mineral phases. Effective metal immobilization was observed with biochar in both contaminated soils but could not be predicted from the sorption isotherms. This immobilization appeared to be governed by the soil pH increase, which induced a greater retention of metals on soil particles. Short‐term effects of biochar on contaminated soils may therefore be controlled by diffusion in biochar particles and by soil alkalinization processes.

In this work, two series of nanocomposites of poly(vinylidene fluoride) (PVDF) incorporated with reduced graphene oxide (rGO) and poly(vinyl alcohol)-modified rGO (rGO-PVA) were fabricated using solution-cast method and their dielectric properties were carefully characterized. Infrared spectroscopy and atom force microscope analysis indicated that PVA chains were successfully grafted onto graphene through ester linkage. The PVA functionalization of graphene surface can not only prevent the agglomeration of original rGO but also enhance the interaction between PVDF and rGO-PVA. Strong hydrogen bonds and charge transfer effect between rGO-PVA and PVDF were determined by infrared and Raman spectroscopies. The dielectric properties of rGO-PVA/PVDF and rGO/PVDF nanocomposites were investigated in a frequency range from 10² Hz to 10⁷ Hz. Both composite systems exhibited an insulator-to-conductor percolating transition as the increase of the filler content. The percolation thresholds were estimated to be 2.24 vol % for rGO-PVA/PVDF composites and 0.61 vol % for rGO/PVDF composites, respectively. Near the percolation threshold, the dielectric permittivity of the nanocomposites was significantly promoted, which can be well explained by interfacial polarization effect and microcapacitor model. Compared to rGO/PVDF composites, higher dielectric constant and lower loss factor were simultaneously achieved in rGO-PVA/PVDF nanocomposites at a frequency range lower than 1 × 10³ Hz. This work provides a potential design strategy based on graphene interface engineering, which would lead to higher-performance flexible dielectric materials.

A computer program, THERGAS, for thé automatic computation of ΔfH°, S° and [Math] of molecules and free radicals in the gas phase has been developed. The calculations use the methods of S.W. Benson: bond and group additivity with ring, cis, ortho, gauche, symmetry and optical isomer corrections - analysis of differences (symmetries, optical isomers, spin, translation, external rotation, vibrations, moments of inertia, potential barriers and BDE) between a free radical R• and its parent molecule RH.

Condensations and cycloadditions can be catalyzed by newly synthesized Cu-doped zeolitic imidazolate frameworks (ZIFs). The catalysts were well characterized and reusable.

Silica-based nanoparticles for applications in photodynamic therapy (PDT) have emerged as a promising field for the treatment of cancer. In this review, based on the pathway the photosensitizer is entrapped inside the silica matrix, the different methods for the synthesis of silica-based nanoparticles are described from the pioneering works to the latest achievements which concern multifunctional nanoplatforms, up-converting nanoparticles, two-photon PDT, vectorization and in vivo applications.

Context. The atmosphere of hot Jupiters can be probed by primary transit and secondary eclipse spectroscopy. Owing to the intense UV irradiation, mixing, and circulation, their chemical composition is maintained out of equilibrium and must be modeled with kinetic models.

Measurements of the Nusselt number Nu and of a Reynolds number ${\mathrm{Re}}_{\mathrm{eff}}$ for Rayleigh-B\'enard convection (RBC) over the Rayleigh-number range ${10}^{12}\ensuremath{\lesssim}\mathrm{Ra}\ensuremath{\lesssim}{10}^{15}$ and for Prandtl numbers Pr near 0.8 are presented. The aspect ratio $\ensuremath{\Gamma}\ensuremath{\equiv}D/L$ of a cylindrical sample was 0.50. For $\mathrm{Ra}\ensuremath{\lesssim}{10}^{13}$ the data yielded $\mathrm{Nu}\ensuremath{\propto}{\mathrm{Ra}}^{{\ensuremath{\gamma}}_{\mathrm{eff}}}$ with ${\ensuremath{\gamma}}_{\mathrm{eff}}\ensuremath{\simeq}0.31$ and ${\mathrm{Re}}_{\mathrm{eff}}\ensuremath{\propto}{\mathrm{Ra}}^{{\ensuremath{\zeta}}_{\mathrm{eff}}}$ with ${\ensuremath{\zeta}}_{\mathrm{eff}}\ensuremath{\simeq}0.43$, consistent with classical turbulent RBC. After a transition region for ${10}^{13}\ensuremath{\lesssim}\mathrm{Ra}\ensuremath{\lesssim}5\ifmmode\times\else\texttimes\fi{}{10}^{14}$, where multistability occurred, we found ${\ensuremath{\gamma}}_{\mathrm{eff}}\ensuremath{\simeq}0.38$ and ${\ensuremath{\zeta}}_{\mathrm{eff}}=\ensuremath{\zeta}\ensuremath{\simeq}0.50$, in agreement with the results of Grossmann and Lohse for the large-Ra asymptotic state with turbulent boundary layers which was first predicted by Kraichnan.

The modeling of biomass gasification processes by simulators such as Aspen Plus is a powerful tool to assess mass and energy balances and to optimize process designs. A detailed model of the gasification reactor is one of the key points to achieve an accurate process description. A model for biomass gasification in dual fluidized bed (DFB) reactors by coupling Aspen Plus and dedicated Fortran files is presented. The DFB is divided into three modules according to the main chemical phenomena: biomass pyrolysis, secondary reactions, and char combustion. Mass yields of permanent gases, water, 10 tar species, and char are modeled with respect to the reactor temperature by a pyrolysis correlation. The secondary reactions are modeled by a semidetailed kinetic mechanism that handles gas-phase and catalytic conversions over char of CH 4 and lumped tar species (phenol, naphthalene, benzene, and toluene), gas-phase water–gas shift reaction (WGSR), char, and soot–steam gasification. The calculated compositions of permanent gases and tars, flow rates, and lower heating values are compared with experimental data for two DFB technologies (Tunzini Nessi Equipment Companies (TNEE) and Battelle High Throughput Gasification Process (FERCO)). The syngas composition and flow rate are very sensitive to the WGSR kinetic. The rate laws for WGSR are reviewed. An optimized kinetic law for WGSR is given.

Functionalisation of MSN with mannose for PDT applications dramatically improved the efficiency of PDT on breast cancer cells.

Mimicking natural structures has been highly pursued in the fabrication of synthetic polymeric materials due to its potential in breaking the bottlenecks in mechanical properties and extending the applications of polymeric materials. Recently, it has been revealed that the energy dissipating mechanisms via sacrificial bonds are among the important factors which account for strong and tough attributes of natural materials. Great progress in synthesis of polymeric materials consisting of sacrificial bonds has been achieved. The present review aims at (1) summarizing progress in the mechanics and chemistry of sacrificial bond bearing polymers, (2) describing the mechanisms of sacrificial bonds in strengthening/toughening polymers based on studies by single-molecule force spectroscopy, chromophore incorporation and constitutive laws, (3) presenting synthesis methods for sacrificial bonding including dual-crosslink, dual/multiple-network, and sacrificial interfaces, (4) discussing the important advances in engineering sacrificial bonding into hydrogels, biomimetic structures and elastomers, and (5) suggesting future works on molecular simulation, viscoelasticity, construction of sacrificial interfaces and sacrificial bonds with high dissociative temperature. It is hoped that this review will provide guidance for further development of sacrificial bonding strategies in polymeric materials.

This paper presents new experimental measurements of the laminar flame velocity of components of natural gas, methane, ethane, propane, and n -butane as well as of binary and tertiary mixtures of these compounds proposed as surrogates for natural gas. These measurements have been performed by the heat flux method using a newly built flat flame adiabatic burner at atmospheric pressure. The composition of the investigated air/hydrocarbon mixtures covers a wide range of equivalence ratios, from 0.6 to 2.1, for which it is possible to sufficiently stabilize the flame. Other measurements involving the enrichment of methane by hydrogen (up to 68%) and the enrichment of air by oxygen (oxycombustion techniques) were also performed. Both empirical correlations and a detailed chemical mechanism have been proposed, the predictions being satisfactorily compared with the newly obtained experimental data under a wide range of conditions.

The oxidation of neat methane (CH4) and CH4 doped with NO2 or NO in argon has been investigated in a jet-stirred reactor at 107 kPa, temperatures between 650 and 1200 K, with a fixed residence time of 1.5 s, and for different equivalence ratios (Φ), ranging from fuel-lean to fuel-rich conditions. Four different diagnostics have been used: gas chromatography (GC), chemiluminescence NOx analyzer, continuous wave cavity ring-down spectroscopy (cw-CRDS) and Fourier transform infrared spectroscopy (FTIR). In the case of the oxidation of neat methane, the onset temperature for CH4 oxidation was above 1025 K, while it is shifted to 825 K with the addition of NO2 or NO, independently of equivalence ratio, indicating that the addition of NO2 or NO highly promotes CH4 oxidation. The consumption rate of CH4 exhibits a similar trend with the presence of both NO2 and NO. The amount of produced HCN has been quantified and a search for HONO and CH3NO2 species has been attempted. A detailed kinetic mechanism, derived from POLIMI kinetic framework, has been used to interpret the experimental data with a good agreement between experimental data and model predictions. Reaction rate and sensitivity analysis have been conducted to illustrate the kinetic regimes. The fact that the addition of NO or NO2 seems to have similar effects on promoting CH4 oxidation can be explained by the fact that both species are involved in a reaction cycle interchanging them and whose result is 2CH3+ O2= 2CH2O + 2H. Additionally, the direct participation of NO2 in the NO2+ CH2O = HONO + HCO reaction has a notable accelerating effect on methane oxidation.