Activity of highly dispersed Co/SBA-15 catalysts (low content) in carbon black oxidation

Peer reviewedPublisher PD

COMBINING MODERATE PULSED ELECTRIC FIELDS WITH TEMPERATURE AND WITH ORGANIC ACIDS TO INACTIVATE ESCHERICHIA COLI SUSPENSIONS

The aim of this work was to study the efficiency of inactivation of Escherichia coli cells in aqueous suspensions using combined moderate pulsed electric field (PEF) and thermal treatments. The inactivation kinetics of E. coli cells in aqueous suspensions (1 wt%) was monitored using conductometric technique. The electric field strength E was within 5-7.5 kV/cm, the effective PEF treatment time was within 0-0.75 s, the pulse duration ti was within 0.3-1 ms, the medium temperature was 30-50°C, and the time of thermal treatment tT was within 0-7000 s. The organic acid concentration was within 0-0.5 g/L.The damage of E. coli was accompanied by release of intracellular components. The synergy between the PEF and thermal treatments in E. coli inactivation was clearly demonstrated. The damage efficiency was noticeably improved by addition of organic acids, especially lactic acid

Inactivation des suspensions microbiennes de Saccharomyces cerevisiae et d Escherichia coli par champs électriques pulsés modérés

Les objectifs de ce travail sont d'étudier les effets de l'application des champs électriques pulsés modérés variant de 2 à 15 kV/cm sur les suspensions colloïdales d'E. coli et de S. cerevisiae. Le Tween 80 ainsi que les acides organiques sont ajoutés aux suspensions d'E. coli pour étudier l'effet de leurs combinaisons au traitement CEP et un degré de destruction de 8 log est atteint. Le suivi de l'évolution de la conductivité durant le traitement des suspensions de S. cerevisiae est utilisé pour suivre le degré de détérioration des cellules. Les données obtenues par le calcul de la conductivité sont en corrélation avec le comptage sur boîtes de Pétri. L'effet du CEP augmente avec le mélange des suspensions, l'augmentation de la température, l'ajout du surfactant et l'utilisation du traitement en continu. L'effet de la charge initiale en S. cerevisiae est étudié et le phénomène de percolation est mis en évidence. La nature de l'agrégation est expliquée par les mesures du potentiel S.The objectives of this study were to investigate the effects of moderate pulsed electric fields (2 to 7.5 kV/cm) on colloidal suspensions of E. coli and S. cerevisiae. Tween 80 as well as organic acids were added to the E. coli suspensions to study the effects of their combinations to the PEF, and a destruction degree of 8 log was reached. The electrical conductivity measurements during the PEF-treatment of S. cerevisiae suspensions were used to monitor the extent of cell damages. Data obtained for the disintegration in conductivity experiments are found in good correlation with Petri dishes cultures counting. The PEF-induced lethality of the yeast cells increases with the mixing of suspensions, the increase of temperature, the adding of surfactant and the use of continuous treatment chamber. The effect of the yeast cells concentrations is studied and the percolation phenomenon is underlined. The nature of the enhanced aggregation was revealed by the S-potential measurements.COMPIEGNE-BU (601592101) / SudocSudocFranceF

Real-time temperature monitoring for Traditional gravel ballasted and Extensive green roofs: A Lebanese case study

International audienc

Effect of Electrofiltration on the Dewatering Kinetics of <i>Arthrospira platensis</i> and Biocompound Recovery

Arthrospira platensis (A. platensis) is a microalga with a wide range of commercial uses. One of the main concerns that needs to be addressed in microalgae biorefineries is the costs associated with the harvesting and concentration steps. Filtration has been shown to be an effective technique for concentrating microalgae and recent studies have attempted to enhance membrane filtration by applying an external electric field to the filtration cell. This study consisted of assessing the use of electrically assisted filtration (electrofiltration) at 60 A/m2 and 1 bar for the dewatering of A. platensis, as well as the effect of pretreating the microalgae with ultrasounds (US) on the filtration process. Untreated A. platensis exhibited better filtration kinetics than US-treated A. platensis, and electrofiltration was found to increase the cake dryness. More protein and pigments were present in the US-treated microalgae solution compared to the untreated microalgae, which led to the presence of higher concentrations of protein and pigments in the filtrate streams after pressure filtration at 1 bar without the application of an external electric field. Electrofiltration was found to consume less energy compared to traditional drying techniques used for A. platensis. However, electrofiltration degrades the biocompounds present in the filtrate and cake due to pH changes and other electrophoresis phenomena, which shows the need to optimize the process in future work

Effect of Electrofiltration on the Dewatering Kinetics of Arthrospira platensis and Biocompound Recovery

Arthrospira platensis (A. platensis) is a microalga with a wide range of commercial uses. One of the main concerns that needs to be addressed in microalgae biorefineries is the costs associated with the harvesting and concentration steps. Filtration has been shown to be an effective technique for concentrating microalgae and recent studies have attempted to enhance membrane filtration by applying an external electric field to the filtration cell. This study consisted of assessing the use of electrically assisted filtration (electrofiltration) at 60 A/m2 and 1 bar for the dewatering of A. platensis, as well as the effect of pretreating the microalgae with ultrasounds (US) on the filtration process. Untreated A. platensis exhibited better filtration kinetics than US-treated A. platensis, and electrofiltration was found to increase the cake dryness. More protein and pigments were present in the US-treated microalgae solution compared to the untreated microalgae, which led to the presence of higher concentrations of protein and pigments in the filtrate streams after pressure filtration at 1 bar without the application of an external electric field. Electrofiltration was found to consume less energy compared to traditional drying techniques used for A. platensis. However, electrofiltration degrades the biocompounds present in the filtrate and cake due to pH changes and other electrophoresis phenomena, which shows the need to optimize the process in future work

Cradle-to-gate Life Cycle Assessment of traditional gravel ballasted, white reflective, and vegetative roofs: A Lebanese case study

International audienc