Grafting luminescent metal-organic species into mesoporous MCM-41 silica from europium(III)tetramethylheptanedionate, Eu(thd)3

Mixed systems with Eu(III) β-diketonates as optically active guest species, and mesoporous silicas MCM-41 as a host matrix have been investigated. The grafting of europium(III) onto the inner walls of unmodified MCM-41 has been achieved starting from Eu(thd)3 (thd = 2,2,6,6- tetramethyl-3,5-heptanedionate), using two routes: wet impregnation (WI) at room temperature,and chemical vapour infiltration (CVI) at 185 °C. In received hybrids, denoted Eu(thd)x@MCM- 41, the same maximum yield [Eu]/[Si] = 8.2 at% on average has been achieved with either methods. The molar ratio x = [thd]/[Eu] is 0.6 on average for WI samples, and 1.5 for CVI samples. In the latter, higher contents in thd compensate lower contents in silanols with respect to the former. Rationalizing the possible bonds exchanged at the silica surface leads to a great diversity of possible co-ordination schemes according to the expression Σ[Si(OH)nx (O)xEu(thd)3-x] (where Σ means that surface species are considered). Chromophore neutral ligands phenanthroline (phen) or bipyridine (bipy) have been added to induce efficient Eu3+ luminescence under 270–280 nm excitation, via the antenna effect. For the most favourable case, (phen)yEu(thd)x@MCM-41, the emission intensity at 612 nm under excitation at 270 nm is 2/3 that for the genuine heteroleptic complex Eu(thd)3(phen). Moreover the hybrid material is stable up to 440 °C

Activated drying in hydrophobic nanopores and the line tension of water

International audienceWe study the slow dynamics of water evaporation out of hydro-phobic cavities by using model porous silica materials grafted with octylsilanes. The cylindrical pores are monodisperse, with a radius in the range of 1–2 nm. Liquid water penetrates in the nanopores at high pressure and empties the pores when the pressure is lowered. The drying pressure exhibits a logarithmic growth as a function of the driving rate over more than three decades, showing the ther-mally activated nucleation of vapor bubbles. We find that the slow dynamics and the critical volume of the vapor nucleus are quantita-tively described by the classical theory of capillarity without adjust-able parameter. However, classical capillarity utterly overestimates the critical bubble energy. We discuss the possible influence of surface heterogeneities, long-range interactions, and high-curvature effects, and we show that a classical theory can describe vapor nucleation provided that a negative line tension is taken into account. The drying pressure then provides a determination of this line tension with much higher precision than currently available methods. We find consistent values of the order of −30 pN in a variety of hydrophobic materials. drying transition | hydrophobicity | kinetics | nanobubbles

Hydrodynamic modelling and the dispersion of water fecal contaminants in current and future climates

10 p.International audienceDuring precipitation events in regions with combined sewers, overflows can occur upstream of drinking water treatment plants. The purpose of the research was to model the transport and propagation of pathogens and pharmaceuticals in the Rivière Des Prairies during flood and low flow events. The water quality is quantified in terms of the behaviour of the river, the interactions of contaminants with the environment and the impacts of climate change. Hydrosim was used for hydrodynamic modeling; Dispersim was used to model the dispersion of contaminants. The impact of climate change was represented by the change of flow in the river. To do so, simulations were performed using Hydrotel, a hydrologic model applied to the Ottawa River. Thus, the impact of dispersion and diffusion of contaminants on the water quality were analyzed to determine the potential impact on raw water quality. Water quality will be affected by lower flows and heavy rains, which will change the frequency distributions of fecal contaminants upon which microbial risk models are based

Amino-Modified Hydrogen-Bonding Resin and its Adsorption on Berberine

A hydrogen-bond donor resin HX was obtained by modifying resin H103 . The adsorption effect of resin HX on berberine was determined. The adsorbing kinetic and dynamic mechanisms of resin HX and resin H103 was compared. The results showed that, after modification, resin HX could form hydrogen-bond with berberine molecules. In the adsorption process, two C-O groups on berberine molecules became the electron acceptor of hydrogen-bond and the N-H group on resin molecules became the electron donor of hydrogen-bond. The existence of hydrogen-bond enhanced the adsorption force, and led to bigger amount of adsorption

Hierarchical porous silica monoliths: A novel class of microreactors for process intensification in catalysis and adsorption

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Catalytic ozonation with γ-Al2O3 to enhance the degradation of refractory organics in water

Nowadays, heterogeneous catalytic ozonation appears as a promising way to treat industrial wastewaters containing refractory pollutants, which resist to biological treatments. Several oxides and minerals have been used and their behavior is subject to controversy with particularly the role of Lewis acid sites and/or basic sites and the effect of salts. In this study, millimetric mesoporous γ-Al2O3 particles suitable for industrial processes were used for enhancing the ozonation efficiency of petrochemical effluents without pH adjustment. A phenol (2,4-dimethylphenol (2,4-DMP)) was first chosen as petrochemical refractory molecule to evaluate the influence of alumina in ozonation. Single ozonation and ozonation in presence of γ-Al2O3 led to the disappearance of 2,4-DMP in 25 min and a decrease in pH from 4.5 to 2.5. No adsorption of 2,4-DMP occurred on γ-Al2O3. Adding γ-Al2O3 in the process resulted in an increase of the 2,4–DMP oxidation level. Indeed, the total organic carbon (TOC) removal was 14% for a single ozonation and 46% for ozonation with γ-Al2O3. Similarly, chemical oxygen demand (COD) removal increases from 35 to 75%, respectively. Various oxidized by-products were produced during the degradation of 2,4-DMP, but after 5 h ozonation 90% of organic by-products were acetic acid > formic acid ≫ oxalic acid. Some of the carboxylic acids were adsorbed on γ-Al2O3. The use of radical scavengers (tert-butanol) highlighted the involvement of hydroxyl radicals during catalytic ozonation with γ-Al2O3 in contrary to single ozonation, which mainly involved direct ozone reaction. γ-Al2O3 is an amphoteric solid with Lewis acid AlOH(H+) sites and basicAl-OH sites. After ozonation the amount of basic sites decreased due to carboxylates adsorption, while the Lewis acid sites remained constant as evidenced by FTIR. Several ozonation runs with γ-Al2O3 reported a progressive decrease of its catalytic activity due to the cumulative sorption of carboxylates on the basic sites. After 80 h of ozonation, a calcination at 550 °C allowed to recover allAl-OH basic sites and the initial activity of γ-Al2O3. A synthetic petrochemical effluent containing various petrochemicals (phenol, acetic acid, naphtenic acid, pyrene, naphtalene) was then treated with γ-Al2O3 with and without NaCl. Sodium ions prevented carboxylates adsorption on γ-Al2O3 leading to a higher efficiency of γ-Al2O3 in presence of NaCl and allowed to decrease the toxicity of the petrochemical effluent

The bioinspired construction of an ordered carbon nitride array for photocatalytic mediated enzymatic reduction

A carbon nitride array (CNA) material has been constructed using a sacrificial diatom template. A regular carbon nitride nanorod array could be replicated from the periodic and regular nanochannel array of the template. The directional charge transport properties and high light harvesting capability of the CNA gives much better performance in splitting water to give hydrogen than its bulk counterpart. Furthermore, by combining with a rhodium complex as a mediator, the nicotinamide adenine dinucleotide (NADH) cofactor of many enzymes could be photocatalytically regenerated by the CNA. The rate of the in situ NADH regeneration is high enough to reverse the biological pathway of the three dehydrogenase enzymes, which then leads to the sustainable conversion of formaldehyde to methanol and also the reduction of carbon dioxide into methanol

The genetic basis of endometriosis and comorbidity with other pain and inflammatory conditions

Endometriosis is a common condition associated with debilitating pelvic pain and infertility. A genome-wide association study meta-analysis, including 60,674 cases and 701,926 controls of European and East Asian descent, identified 42 genome-wide significant loci comprising 49 distinct association signals. Effect sizes were largest for stage 3/4 disease, driven by ovarian endometriosis. Identified signals explained up to 5.01% of disease variance and regulated expression or methylation of genes in endometrium and blood, many of which were associated with pain perception/maintenance (SRP14/BMF, GDAP1, MLLT10, BSN and NGF). We observed significant genetic correlations between endometriosis and 11 pain conditions, including migraine, back and multisite chronic pain (MCP), as well as inflammatory conditions, including asthma and osteoarthritis. Multitrait genetic analyses identified substantial sharing of variants associated with endometriosis and MCP/migraine. Targeted investigations of genetically regulated mechanisms shared between endometriosis and other pain conditions are needed to aid the development of new treatments and facilitate early symptomatic intervention

The genetic basis of endometriosis and comorbidity with other pain and inflammatory conditions

Endometriosis is a common condition associated with debilitating pelvic pain and infertility. A genome-wide association study meta-analysis, including 60,674 cases and 701,926 controls of European and East Asian descent, identified 42 genome-wide significant loci comprising 49 distinct association signals. Effect sizes were largest for stage 3/4 disease, driven by ovarian endometriosis. Identified signals explained up to 5.01% of disease variance and regulated expression or methylation of genes in endometrium and blood, many of which were associated with pain perception/maintenance (SRP14/BMF, GDAP1, MLLT10, BSN and NGF). We observed significant genetic correlations between endometriosis and 11 pain conditions, including migraine, back and multisite chronic pain (MCP), as well as inflammatory conditions, including asthma and osteoarthritis. Multitrait genetic analyses identified substantial sharing of variants associated with endometriosis and MCP/migraine. Targeted investigations of genetically regulated mechanisms shared between endometriosis and other pain conditions are needed to aid the development of new treatments and facilitate early symptomatic intervention

The use of H2O2 over titanium-grafted mesoporous silica catalysts : a step further towards sustainable epoxidation

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