220 research outputs found

    Polyphenol, polysaccharide and lactate extraction from pulping factory black liquor by ionic liquids

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    International audienceExtraction of polyphenols, polysaccharides and organic acids present in a liquor issued from a pulping factory, so-called black liquor, was studied using two ionic liquids trihexyltetradecylphosphonium chloride ([P 66614 ]Cl) and trihexyltetradecylphosphonium bromide ([P 66614 ]Br). The extraction of each of the three compounds mentioned above was reported as a function of the dilution of the initial black liquor, the volume ratio of liquor vs. ionic liquid, and the initial pH of the black liquor. Polyphenols and polysaccharides were quantitatively extracted at room temperature with both ionic liquids. Extraction of lactate anions was found to be low, exhibiting distribution coefficients below 8 in all cases

    Evidence of connections between cerebrospinal fluid and nasal lymphatic vessels in humans, non-human primates and other mammalian species

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    BACKGROUND: The parenchyma of the brain does not contain lymphatics. Consequently, it has been assumed that arachnoid projections into the cranial venous system are responsible for cerebrospinal fluid (CSF) absorption. However, recent quantitative and qualitative evidence in sheep suggest that nasal lymphatics have the major role in CSF transport. Nonetheless, the applicability of this concept to other species, especially to humans has never been clarified. The purpose of this study was to compare the CSF and nasal lymph associations in human and non-human primates with those observed in other mammalian species. METHODS: Studies were performed in sheep, pigs, rabbits, rats, mice, monkeys and humans. Immediately after sacrifice (or up to 7 hours after death in humans), yellow Microfil was injected into the CSF compartment. The heads were cut in a sagittal plane. RESULTS: In the seven species examined, Microfil was observed primarily in the subarachnoid space around the olfactory bulbs and cribriform plate. The contrast agent followed the olfactory nerves and entered extensive lymphatic networks in the submucosa associated with the olfactory and respiratory epithelium. This is the first direct evidence of the association between the CSF and nasal lymph compartments in humans. CONCLUSIONS: The fact that the pattern of Microfil distribution was similar in all species tested, suggested that CSF absorption into nasal lymphatics is a characteristic feature of all mammals including humans. It is tempting to speculate that some disorders of the CSF system (hydrocephalus and idiopathic intracranial hypertension for example) may relate either directly or indirectly to a lymphatic CSF absorption deficit

    Selective separation of manganese, cobalt, and nickel in a fully aqueous system

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    The continued electrification of society and the related growing demand for rechargeable batteries require in turn the elaboration of efficient and sustainable recycling strategies for their recovery and valorization. An important separation relevant to nickel metal hydride (NiMH) and lithium-ion battery recycling is the intertransition element separation between Ni(II), Co(II), and Mn(II). In this work, a fully aqueous process for the recovery of Mn(II) and Co(II) from concentrated Ni(II) effluents typical of NiMH battery leachate is disclosed consuming only Na2CO3. In the first instance, Mn is selectively precipitated as Mn(IV) by oxidation using ozone as an oxidant, resulting in a significant enrichment of Mn in the precipitate relative to its original solution concentration. Second, a thermo- and acid-responsive aqueous biphasic system (ABS) based on the ionic liquid (IL) tributyltetradecylphosphonium chloride ([P44414]Cl) and NiCl2 was used to recover Co(II). By using the high NiCl2 content found in NiMH leachates both as the ABS phase former and salting-out agent, no additional salt is required. Through careful manipulation of the Co(II) to Ni(II) and the IL to Co(II) molar ratios, an effective and selective separation of Co(II) from Ni(II) was achieved. Finally, Co(II) is precipitated from the IL-rich phase and the IL is regenerated in one step by the addition of Na2CO3 to induce a new phase separation.publishe

    Explaining Ionic Liquid Water Solubility in Terms of Cation and Anion Hydrophobicity

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    The water solubility of salts is ordinarily dictated by lattice energy and ion solvation. However, in the case of low melting salts also known as ionic liquids, lattice energy is immaterial and differences in hydrophobicity largely account for differences in their water solubility. In this contribution, the activity coefficients of ionic liquids in water are split into cation and anion contributions by regression against cation hydrophobicity parameters that are experimentally determined by reversed phase liquid chromatography. In this way, anion hydrophobicity parameters are derived, as well as an equation to estimate water solubilities for cation-anion combinations for which the water solubility has not been measured. Thus, a new pathway to the quantification of aqueous ion solvation is shown, making use of the relative weakness of interactions between ionic liquid ions as compared to their hydrophobicities

    Ionic liquids for rechargeable lithium batteries (Preliminary report, Sept. 21, 2005)

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    Abstract We have investigated possible anticipated advantages of ionic-liquid electrolytes for use in lithium- Introduction A general trend in modern chemical engineering is to move to environmentally friendly processes. New chemical processes should be designed to reduce or eliminate generation of hazardous wastes. Ionic liquids are expected to provide alternatives for a variety of industrial-scale applications and for electrochemical devices. Numerous ionic liquids are known but only a small number has been investigated; for most of them, only a few properties have been studied. Because ionic liquids are nonvolatile at ordinary temperatures, and because they are non-flammable, they provide potential environmental advantages relative to conventional solvents. Properties and applicability of ionic liquids are not easily predicted. Solutes, impurities, undesired or desired reaction products alter the physical, chemical, and electrochemical behavior of a particular system. Interactions of ionic liquids with materials, or unwanted chemical reactions can eliminate the anticipated advantages in industrial applications. Knowledge of pure-component properties of ionic liquids is essential but not sufficient

    Multiplicity of cerebrospinal fluid functions: New challenges in health and disease

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    This review integrates eight aspects of cerebrospinal fluid (CSF) circulatory dynamics: formation rate, pressure, flow, volume, turnover rate, composition, recycling and reabsorption. Novel ways to modulate CSF formation emanate from recent analyses of choroid plexus transcription factors (E2F5), ion transporters (NaHCO3 cotransport), transport enzymes (isoforms of carbonic anhydrase), aquaporin 1 regulation, and plasticity of receptors for fluid-regulating neuropeptides. A greater appreciation of CSF pressure (CSFP) is being generated by fresh insights on peptidergic regulatory servomechanisms, the role of dysfunctional ependyma and circumventricular organs in causing congenital hydrocephalus, and the clinical use of algorithms to delineate CSFP waveforms for diagnostic and prognostic utility. Increasing attention focuses on CSF flow: how it impacts cerebral metabolism and hemodynamics, neural stem cell progression in the subventricular zone, and catabolite/peptide clearance from the CNS. The pathophysiological significance of changes in CSF volume is assessed from the respective viewpoints of hemodynamics (choroid plexus blood flow and pulsatility), hydrodynamics (choroidal hypo- and hypersecretion) and neuroendocrine factors (i.e., coordinated regulation by atrial natriuretic peptide, arginine vasopressin and basic fibroblast growth factor). In aging, normal pressure hydrocephalus and Alzheimer's disease, the expanding CSF space reduces the CSF turnover rate, thus compromising the CSF sink action to clear harmful metabolites (e.g., amyloid) from the CNS. Dwindling CSF dynamics greatly harms the interstitial environment of neurons. Accordingly the altered CSF composition in neurodegenerative diseases and senescence, because of adverse effects on neural processes and cognition, needs more effective clinical management. CSF recycling between subarachnoid space, brain and ventricles promotes interstitial fluid (ISF) convection with both trophic and excretory benefits. Finally, CSF reabsorption via multiple pathways (olfactory and spinal arachnoidal bulk flow) is likely complemented by fluid clearance across capillary walls (aquaporin 4) and arachnoid villi when CSFP and fluid retention are markedly elevated. A model is presented that links CSF and ISF homeostasis to coordinated fluxes of water and solutes at both the blood-CSF and blood-brain transport interfaces
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