Heterogeneous catalysts were synthesized with a glass foam support mainly composed of recycled glass and impregnated with zerovalent ruthenium nanoparticles (aiming to 0.1 wt.% ruthenium). Different glass foams were developed, playing on the nature and quantity of foaming/doping agents as well as the operating conditions (heat temperature and time of heating). They were characterized in terms of open porosity, pore diameter, wettability and pressure drops. High open porosity can be achieved (between 73% and 92%) with mean pore diameter up to 0.55 mm, resulting in the lowest pressure drops measured among all glass foams. The deposit of zerovalent ruthenium nanoparticles was confirmed by TEM images and changes in surface charge showed by zeta potential determination. Finally, the removal of ozone from air at room temperature and inlet concentration of 9 g.Nm-3 was performed to prove the catalyst activity. Up to 52% of ozone decomposition was achieved in less than 13 seconds of residence time. The activity did not seem to be linked with the characteristics (open porosity and mean pore size) of the glass foams but it was shown that the external mass transfer was still limiting the process performances in the range of superficial gas velocity tested (4 mm.s-1 to 11 mm.s-1).

et al.. Air-gap membrane distillation for the separation of bioethanol from algal-based fermentation broth. Separation and Purification Technology, Elsevier, 2019, 213, pp. Abstract :More than 80 % of the energy consumed in the world comes from fossil fuels alone. However, fermentative production of bioethanol has recently gained a considerable interest as an alternative and renewable fuel. Among the different biomasses, the use of macro-algae hydrolysate as the fermentation substrate has been shown to be interesting. However, after fermentation, ethanol has to be separated from the complex broth containing numerous compounds such as microorganisms, fermentation co-products, non-fermentable organic matter, salts, etc. In this study, Air-Gap Membrane Distillation (AGMD) was evaluated to extract ethanol from these complex mixtures.Experiments were conducted using synthetic mixtures and real algal-based fermentation broths.AGMD was able to obtain an ethanol-enriched permeate while other compounds were retained by the membrane. Furthermore, by adjusting the operating parameters, it was possible to maximize the process productivity and selectivity at the same time. Finally, working with the real biofluids revealed that AGMD operation was robust toward membrane wetting, even in presence of membrane fouling.AGMD was thus demonstrated to be a suitable technique for bioethanol extraction from algal-based fermentation broths.

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Yeast strains were isolated from sugar cane molasses (S1), dates (S2) and figs (S3) and the ethanol production was evaluated in batch condition. A comparison was made with the yeast Saccharomyces cerevisiae. The strains showed tolerant characteristics to stressful conditions like salinity and ethanol. The isolated strains produced ethanol; at 20 h of fermentation ethanol yields were 0.38-0.39 g.g-1 , and the productivities were almost 0.58 g.L-1. S. cerevisiae and S1 tolerated up to 14% (v/v) of ethanol; while interestingly the isolates S2 and S3 were highly tolerant, up to 20% (v/v) ethanol. Thus, S2 and S3 could serve as potential strains for ethanol fermentation, with 0.27 and 0.29 g.g-1 yield of ethanol in the presence of 1.37 mol.L-1 NaCl. These values were higher than the value obtained using the yeast of reference and S1 (0.16 g.g-1). Co-cultures of S2 and S3 enhanced the ethanol production, increasing the yield of ethanol by 12.5% compared with the single culture. The strains were identified as species S.cerevisiae, and S2 and S3 were very similar. For an application in the valorization of biomass such as green macro-algae, some assays were done on a synthetic model medium of hydrolysate of macro-algae and the strains S2 and S3 demonstrated excellent fermentative performances.

An open cell foam catalyst consisting of a glass foam support impregnated with zerovalent ruthenium nanoparticles (aiming to 0.1 wt %) without washcoating was used for the first time to remove several volatile organic compounds (VOCs) by thermocatalytic oxidation. At initial concentrations between and 2 g·m–3 and temperatures ranging from 100 to 350 °C, up to 100% of removal was achieved for the four VOCs tested. The ease of abatement of the VOCs with temperature had the following order: ethanol > acetone > toluene > heptane. The removal of ethanol was then modeled considering mass-transfer limitation, temperature dependency, and by-product formation. Full mineralization of ethanol can be achieved with a 30 cm length reactor at 150 °C and 0.010 m·s–1. While the tortuous foam achieved efficient mass transfer, the process was still limited by this phenomenon highlighting that the efficiency of the catalyst could be improved at higher gas velocities.

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A heterogeneous catalyst, composed of an open-cell glass foam support impregnated with zerovalent ruthenium nanoparticles (loading around 0.1 wt.%), was used to remove toluene in air by catalytic ozonation. Experiments with lab-designed 2-6 cm length and 1.6 cm diameter catalysts were performed. A model based on the Langmuir-Hinshelwood mechanism, coupled with mass transfer limitations and including competitive effects between toluene and ozone, was designed. It accurately fits experimental data gathered at various temperatures (30-90°C), gas velocities (0.0025-0.017 m.s -1 ) and inlet ozone concentrations (6.4-11.2 g.m -3 ). The removal of ozone and toluene was mainly ruled by the ozone concentration at low concentrations while the adsorption competition becomes significant at high ozone concentrations.Predictive simulations, at 1.0 g.m -3 inlet toluene concentration, were compared in terms of investment cost, operating cost and process performances. The results highlighted the complexity of the process, which involves antagonist aims between toluene removal and the design of a compact and energy-efficient reactor. With the best operating conditions (90°C and 46 g.m -3 ozone inlet concentration), the removal of toluene reached 88% (removal rate of J o u r n a l P r e -p r o o f 0.25 g.m -3 .s -1 ) with a high ozone degradation (97%) in a moderate reactor length of 0.11 m. These good performances associated to the low cost of the catalyst's synthesis make it an efficient alternative for the removal of pollutants from air.