Introduction of nanofiltration in a production process of fermented organic acids

Nanofiltration in a production process of fermented organic acid

Investigation of nanofiltration as a purification step for lactic acid production processes based on conventional and bipolar electrodialysis operations

Nanofiltration was investigated for usability in a specific lactic acid production process based on conventional and bipolar electrodialysis operations. Industrial fluids, corresponding to two potential integration levels and coming from an existing installation, were investigated. The commercially available DK nanofiltration membrane was used and performances in terms of lactate/lactic acid recovery rate and purification efficiency are reported. Nanofiltration was able to efficiently remove magnesium and calcium ions from a sodium lactate fermentation broth before its concentration and conversion by electrodialysis (first potential integration level). Maximum impurities rejections and lactate recovery were obtained at maximum transmembrane pressures. Mg2+ and Ca2+ rejections were 64±7 and 72±7%, respectively and lactate recovery rate reached 25±2 molm−2 h−1 for P = 20 bar. Sulfate and phosphate ions were also partially removed from the broth (40% rejection). At the invert, chloride ions were negatively retained by the membrane and were consequently more concentrated in the permeate. Nanofiltration also led to a nearly total decolouration of the fermentation broth. On the other hand, sulfate and phosphate rejections obtained from the filtration of a converted broth containing the lactic acid under its neutral form (second potential integration level) were also satisfactory, i.e. 47±5 and 51±5%, respectively. High recovery rates were observed in that case, i.e. 48±2 molm−2 h−1 at 20 bar. It indicated that NF could also be used as final purification step in the process

Production processes of fermented organic acids targeted around membrane operations: design of the concentration step by conventional electrodialysis

Organic acids are increasingly used for various industrial applications. Their production is mainly achieved by fermentation. Precipitation or extraction stages, which generate big amount of effluents, are then traditionally used to get the acid in a suitable form. To lower the impact on the environment, the implementation of cleaner operations are investigated. In this context, a complete process targeted around membrane operations for clarification, concentration and conversionwas studied. The present paper is devoted to the study of the concentration step, carried out by conventional electrodialysis (EDC). A model, based on the description of the solute and solution fluxes through the membranes is developed. Dedicated procedures are proposed to determine the different contributions, i.e. electromigration and diffusion, to these fluxes so as to feed the model. This approach is then applied to the concentration of sodium lactate solutions. The preponderance of electromigration is thus demonstrated as well as the existence of a maximum achievable concentration, the predicted value of which is confirmed experimentally. Comparison between EDC of sodium and ammonium lactate solutions shows that the counter ion has negligible influence on the transport of lactate. The influence of the membrane characteristics is also drawn from comparison with previously published results. Finally, the predictions of the model are compared with the experimental results concerning the concentration of a fermentation broth and a good agreement is stated. The approach proposed in this paper can be used as well to design EDC concentration of any other organic acid salt than lactate

Chronic cluster headache and the pituitary gland

Background: Cluster headache is classified as a primary headache by definition not caused by an underlying pathology. However, symptomatic cases of otherwise typical cluster headache have been reported. Case presentation: A 47-year-old male suffered from primary chronic cluster headache (CCH, ICHD-3 beta criteria fulfilled) since the age of 35 years. A magnetic resonance imaging (MRI) study of the brain in 2006 came back normal. He tried several prophylactic treatments but was never longer than 1 month without attacks. He was under chronic treatment with verapamil with only a limited effect on the attack frequency. Subcutaneous sumatriptan 6 mg injections were very effective in aborting attacks. By February 2014 the patient developed a continuous interictal pain ipsilateral to the right-sided cluster headache attacks. An indomethacin test (up to 225 mg/day orally) was negative. Because of the change in headache pattern we performed a new brain MRI, which showed a cystic structure in the pituitary gland. The differential diagnosis was between a Rathke cleft cyst and a cystic adenoma. Pituitary function tests showed an elevated serum prolactin level. A dopamine agonist (cabergoline) was started and the headache subsided completely. Potential pathophysiological mechanisms of pituitary tumor-associated headache are discussed. Conclusion: Neuroimaging should be considered in all patients with CCH, especially those with an atypical presentation or evolution. Response to acute treatment does not exclude a secondary form of cluster headache. There may be shared pathophysiological mechanisms of primary and secondary cluster headache

Nanofiltratio of glucose and sodium lactate solutions Variations of retention between single- and mixed-solute solutions

The aim of this work was to investigate NF as a purificatio step, i.e. sugar removal, in the production process of lactic acid from sodium lactate fermentation broth. Experiments were carried out with the Desal 5 DK membrane and solutions of increasing complexity, i.e. single-solute solutions of sodium lactate and glucose and mixed-solute solutions containing both solutes. Concentrations close to those of a fermentation broth were chosen. Experimental results were used to get the variations of the intrinsic retention versus the permeation flu in order to achieve comparisons without the interference of concentration polarization. Quite distinct retentions were obtained for glucose and sodium lactate in single-solute solutions so that the purificatio was expected to be feasible. However, it is pointed out that glucose retention is significantl lower in mixed-solute solutions, i.e. when sodium lactate is present. This decrease is such that the retentions of both solutes become comparable so that any purificatio is unachievable. Experiments were also performed with a salt of a different nature (mineral salt, NaCl). Again, it was found that the presence of NaCl tends to decrease glucose retention. Moreover, the phenomenon is shown to be related to the salt concentration in both cases, i.e. with sodium lactate and NaCl. Some possible explanations of this effect are provided in this paper. Further investigations are still in progress to improve the knowledge of the mechanisms involved

Modelling of the conversion of weak organic acids by bipolar membrane electrodialysis

Organic acids are increasingly used for various industrial applications. Their production is mainly achieved by fermentation. Precipitation or extraction stages, which generates big amount of effluents, are then traditionally usedto get the acid in a suitable form. Bipolar membrane electrodia lysis (EDBM) can be used to achieve the conversion of the acid salt into its acidic form. Its introduction in replacement of precipitation can significantly lower the environmental impact of the process. This paper is focused on the modelling of the conversion of weak organic acid salts by EDBM The different mass transfer phenomena involved in the system are first identified. A model is then established to get expressions providing the evolution of the product and effluent lines with respect to the operating conditions. The physical meaning of the characteristic parameters involved in the model is also discussed

Seniors et tablettes interactives - Livre blanc

L’apparition des terminaux mobiles dotés d’écrans tactiles a constitué une véritable rupture dans les usages de l’Internet. Ces nouvelles interfaces simplifiées ont permis d’introduire une nouvelle « grammaire gestuelle » auprès de l’ensemble des utilisateurs. En introduisant une nouvelle forme de « mobilité domestique », ces terminaux ont aussi permis d’intégrer plus étroitement ces services à la vie quotidienne des citoyens. Plutôt que de créer des technologies spécifiquement dédiées aux seniors, il est désormais possible de faire évoluer les outils et les services « grand public » afin que les seniors puissent en bénéficier. En effet, l’ergonomie constitue désormais un facteur crucial pour la démocratisation des services de l’Internet. L’objectif de la Délégation aux Usages de l’Internet en publiant ce livre blanc est de permettre à l’ensemble des acteurs de l’Internet (constructeurs de terminaux et concepteurs de services mobiles) de mieux prendre en compte les besoins des seniors. Ce livre blanc a été élaboré à l’issue d’une étude menée par le laboratoire du CNRS Le Lutin avec l’association d’entreprises Silicon Sentier

CHARACTERISTICS OF DETECTION LINEAR POLARIZED RADARS SIGNALS

The article considers the characteristics of detection of linear polarized radars performance of angle orientation plane polarization radiowave

Environmental Impacts of Tartaric Stabilisation Processes for Wines using Electrodialysis and Cold Treatment

The environmental impacts of the two tartaric stabilisation methods used for wines, electrodialysis andcold treatment, were studied by determining water consumption (for the process and cleaning), wasteproduced (organic load and the composition of wastewater and residues) and energy consumption, atthe pilot stage and in wineries. Thanks to an online treatment of electrodialysis brines by reverse osmosis(industrial facility that treats 30 hL wine/h), the recycling of permeates led to a 65% reduction in waterconsumption, the volume of which represented only 3.9% of the wine treated. When washing and cleaningwater from the ED-RO system was taken into account, overall water consumption was 5.5 L/hL wine. Thepresence of ethanol, due to an osmotic phenomenon with no loss of wine volume, and tartaric acid in thebrines contributes to the organic load of the brine, with a COD of close to 8.4 g O2/L. Overall electricalenergy consumption for stabilisation by electrodialysis (0.21 kWh/hL) turned out to be eight times lowerthan that of cold stabilisation. An evaluation of cold stabilisation effluents revealed that 66.6% of the CODdischarged came from the diatomaceous earth (DE), 21.8% from the washing of the filter and 11.4% fromthe washing of the cold treatment tank. The production of used DE was 2.64 g (wet weight)/L of wine, andthe ethanol present in the DE waste represented a loss in wine volume of 0.14 L/hL