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Soot samples from different fuels were produced in small and pilot combustion test benches at various O 2 concentrations, and were then characterized in terms of primary particle diameter, specific surface area and oxygen content/speciation. Water sorption measurements were then carried out for soot compacted into pellet form and in powder form, using both a gravimetric microbalance and a manometric analyser. Water adsorption isotherms are all found to be Type V, and reveal the central role of the specific surface area and the oxygen content of soot. A single parametrization of the second Dubinin-Serpinsky model gives a proper fit for all isotherms. To the best of our knowledge, this is the first study to provide physico-chemical parameters and water sorption results for fire soot. This enables a better description of the soot cake formed on filters during a fire, in particular in industrial confined facilities as simulated in this study. Humidity can be then explicitly considered in the same way as other parameters influencing the aeraulic resistance of soot cakes. These results can be used to improve predictions of the consequences of fires on the containment of toxic materials within industrial facilities., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This paper deals with the ability of electrocoagulation (EC) to remove simultaneously COD and chromium from a real chrome tanning wastewater in a batch stirred electro-coagulation cell provided with two aluminium-based electrodes (aluminium/copper/magnesium alloy and pure aluminium). Effects of operating time, current density and initial concentration of Cr(III) and COD have been investigated. The concentrations of pollutants have been successfully reduced to environmentally acceptable levels even if the concentrated effluent requires a long time of treatment of around 6h with a 400A/m(2) current density. The aluminium alloy was found to be more efficient than pure aluminium for removal of COD and chromium. Dilution of the waste has been tested for treatment: high abatement levels could be obtained with shorter time of treatment and lower current densities. Energy consumption of the electrocoagulation process was also discussed. The dilution by half of the concentrated waste leads to a higher abatement performance of both COD and chromium with the best energy efficiency., (Copyright © 2016 Elsevier B.V. All rights reserved.)

3-Aminopropyltrimethoxysilane (APTMS) was used as ligand to prepare ZnO@APTMS, Cu(2+)-doped ZnO (ZnO:Cu@APTMS) and ZnO quantum dots (QDs) with chemisorbed Cu(2+) ions at their surface (ZnO@APTMS/Cu). The dots have a diameter of ca. 5 nm and their crystalline and phase purities and composition were established by X-ray diffraction, transmission electron microscopy, UV-visible and fluorescence spectroscopies and by X-ray photoelectron spectroscopy. The effect of Cu(2+) location on the ability of the QDs to generate reactive oxygen species (ROS) under light irradiation was investigated. Results obtained demonstrate that all dots are able to produce ROS (OH, O2(-), H2O2 and (1)O2) and that ZnO@APTMS/Cu QDs generate more OH and O2(-) radicals and H2O2 than ZnO@APTMS and ZnO:Cu@APTMS QDs probably via mechanisms associating photo-induced charge carriers and Fenton reactions. In cytotoxicity experiments conducted in the dark or under light exposure, ZnO@APTMS/Cu QDs appeared slightly more deleterious to Escherichia coli cells than the two other QDs, therefore pointing out the importance of the presence of Cu(2+) ions at the periphery of the nanocrystals. On the other hand, with the lack of photo-induced toxicity, it can be inferred that ROS production cannot explain the cytotoxicity associated to the QDs. Our study demonstrates that both the production of ROS from ZnO QDs and their toxicity may be enhanced by chemisorbed Cu(2+) ions, which could be useful for medical or photocatalytic applications., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The toxicity of quantum dots (QDs) has been commonly attributed to the release of metal ions from the core as well as to the production of reactive oxygen species. However, the information related to the stability of the nanoparticles are relatively scarce although this parameter may strongly influence their toxicity. The stability of aminosilane-capped ZnO QDs, here used as model nanoparticles, was investigated by inductively coupled plasma-optical emission spectrometer (ICP-OES) and whole cell biosensors using a dialysis setup to separate the QDs from the leaked Zn(2+) ions. The integrity of the ZnO QDs appeared strongly affected by their dilution in aqueous medium, whereas the nanoparticles were slightly stabilized by bacteria. Our results demonstrate some inadequacy between the implementation and use of whole cell biosensors, and the monitoring of metal release from QDs., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Mercaptosuccinic acid-capped CdSe and alloyed CdSe(S) QDs were prepared in aqueous solution at 100 and 170°C, respectively. These dots were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-vis and photoluminescence spectroscopies. The dots were found to be of similar size (ca. 2nm) but differ in their composition and surface chemistry. The photostability of the QDs was found to correlate with their ability to produce reactive oxygen species (ROS) upon light activation. CdSe QDs produce hydroxyl radicals immediately after irradiation due to their modest photostability, while CdSe(S) QDs start to generate the hydroxyl radicals only once they start to be bleached (ca. 30min). Cytotoxicity experiments conducted on Escherichia coli cells revealed that CdSe QDs were the more toxic despite being the least loaded in cadmium. In addition, consistent with ROS assays, the cytotoxicity of the CdSe QDs appeared light-dependent and is in accordance with a light-dependent oxidative stress observed with an oxyR-based whole cell biosensor. Our results demonstrate the crucial role played by nanoparticles synthesis process on their PL properties, their stability and their toxicity., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The most effective and widely used dedusting techniques to separate nanoparticles of a carrier fluid are fibrous media. The main problem is the clogging of the filter that induces a pressure drop increase over time and thus requires a regular cleaning of the media (or its replacement). Following these observations, this study proposes to investigate the potential of bubble columns for nanoparticles collection. Despite collection efficiencies lower than those of fibrous filters, experimental results show that bubble columns present likely performances for the collection of nanoparticles and have collection efficiency even more important when the liquid height is high and bubbling orifices have low diameters. Experiments have also revealed the presence of a most penetrating particle size for a particle diameter range between 10 and 30 nm. The model developed in this article highlights a good agreement between the theoretical collection efficiency by Brownian diffusion and experimental collection efficiencies for particles lower than 20 nm. Nevertheless, the modelling may be extended to other collection mechanisms in order to explain the collection efficiency increase for particles higher than 20 nm and to confirm or infirm that electrostatic effects can be the cause of this efficiency increase., (Copyright © 2011 Elsevier B.V. All rights reserved.)