Search results for "aqueous solution"
showing 10 items of 1610 documents
Modulation of retention and selectivity in oil-in-water microemulsion liquid chromatography: A review
2019
Microemulsions (MEs) are stable, isotropically clear solutions consisting of an oil and water stabilized by a surfactant and a co-surfactant. Oil-in-water microemuslion liquid chromatography (MELC) is a relatively new chromatographic mode, which uses an O/W ME as mobile phase. Retention, selectivity and efficiency can be modified by changing the concentration of the ME components and the ratio between the aqueous and oil phases. This work makes a critical survey on the information found in the literature about the mobile phase compositions that lead to the creation of successful O/W ME mobile phases, as well as the effect of pH for ionizable compounds and temperature. The viability of perfo…
Study of the structural phase transformation of iron oxide nanoparticles from an Fe2+ ion source by precipitation under various synthesis parameters …
2015
Abstract Magnetite nanoparticles were precipitated from a pure aqueous ferrous salt solution in an air atmosphere. The influence of the solution molarity, the rate of precipitator agent addition, stirring time and annealing temperature was studied. The morphology, crystalline phase purity and magnetic properties of the obtained powders were studied by X-Ray powder diffraction (XRD), Scanning electron microscopy (SEM), Differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and Vibrating sample magnetometer (VSM). The synthesis conditions were seen to have an effect on phase composition. It was possible to obtain near stoichiometric Fe…
Synthesis, stability and spectral behavior of fluorogenic sulfone-pyronin and sulfone-rosamine dyes
2018
International audience; The first synthesis of sulfone-pyronin and sulfone-rosamine dyes bearing optically tunable primary amino groups (acting as fluorogenic centers) is presented. Sulfone analogs of xanthene-based fluorophores have recently been highlighted as a new class of near-infrared (NIR) fluorescent dyes (Liu et al. ACS Appl Mater Interfaces 2016; 8(35):22953-62), and the availability of fluorogenic derivatives is essential for the rapid construction of “turn-on” reactive probes for chemoselective bioimaging. However, these fluorescent anilines have been found to be unstable in aqueous physiological conditions due to the marked electrophilicity of their meso-position and hence its …
Biosorption of nickel (II) and zinc (II) from aqueous solutions by the biomass of yeast Yarrowia lipolytica
2017
Abstract This study examined the biosorption process of Ni(II) and Zn(II) from an aqueous solution by dead biomass of Yarrowia lipolytica. Optimum biosorption conditions were determined as a function of pH, biomass dosage, contact time, and temperature. The biosorbent was characterized by FTIR, which indicated the participation of hydroxyl, carboxyl, amide and amine groups in the process of binding the metal ions. The results showed that the biosorption processes of both metal ions closely followed pseudo-second order kinetics. The equilibrium data of Ni(II) and Zn(II) ions at 20, 30 and 40°C fitted the Langmuir and Freundlich isotherm models. Langmuir isotherm provided a better fit to the …
Improvement of photo-stability of LLDPE-based nanocomposites
2006
LLDPE-based nanocomposites undergo faster photo-oxidation than the unfilled matrix and the extent of their physical properties deterioration, namely elongation at break and tensile strength, is dependent on the organo-nanoclay loading. The observed acceleration is not due to faster photo-oxidation but rather due to a reduction of the oxidation induction time. The presence in the organoclays of trace amounts of metal ions may be promoting catalytic photodegradation. While UV absorbers provide useful protection, use of a metal deactivator has been found to greatly enhance the photo-stability of the LLDPE-based nanocomposites. Combinations of a metal deactivator and UV absorber yield synergist…
The formal redox potential of the Yb(III,II) Couple at 0°C in 3.22 molal NaCl medium
2004
Following our previous investigations on aqueous solutions of hypooxidized and iperoxidized species, we managed, by lowering the temperature of the solutions to 0 degrees C, to obtain, by electrochemical methods, Yb(II) and Yb(III) mixtures, enough stable to determine by a potentiometric method the formal redox potential of the Yb(IlI, II) couple. Its value, in a large range of total Ytterbium concentration, is -1233 +/- 3 mV against the molal hydrogen electrode in the 3.22 m NaCl medium.
Straightforward access to water-soluble unsymmetrical sulfoxanthene dyes: application to the preparation of far-red fluorescent dyes with large stoke…
2014
An efficient synthesis of water-soluble unsymmetrical sulforhodamine/sulforhodol fluorophores containing a single julolidine fragment is presented. Owing to their valuable spectral properties in aqueous buffers, these dyes, especially those bearing a free aniline or phenol moiety, are valuable components of fluorogenic probes for a variety of biosensing applications. A further extension of this synthetic methodology to unusual phenols, namely 7-N,N-dialkylamino-4-hydroxy coumarins has enabled us to provide a new family water-soluble dyes of large Stokes’ shift with far-red spectral features.
Towards enhanced durability of electrochromic WO3 interfaced with liquid or ceramic sodium-based electrolytes
2020
Abstract The reversible intercalation of sodium ion into tungsten oxide WO3 appears as an interesting alternative to hydrogen or lithium ion reduction in order to get the characteristic transition from clear transparent to bluish coloration in electrochromic devices, but it has been comparatively less considered. In order to address further viable all-ceramic devices based on sodium ion intercalation and overcome the issue of WO3 degradation in aqueous media, three configurations of WO3 thin film-based electrochromic half-cells were tested, namely in (i) aqueous acidified Na2SO4 electrolyte, (ii) room temperature ionic liquid BEPipTFSI electrolyte and (iii) aqueous acidified Na2SO4 electrol…
Response of Chlamydomonas reinhardtii to Herbicides: Negative Relationship Between Toxicity and Water Solubility Across Several Herbicide Families
2002
International audience
Task-specific ionic liquid for the depolymerisation of starch-based industrial waste into high reducing sugars
2014
Development of a simple route for the catalytic conversion of starch-based industrial waste (potato peels) and potato starch into reducing sugars was investigated in two ionic liquids for comparison – 1-allyl-3-methylimidazolium chloride [AMIM]Cl and 1-(4-sulfobutyl)-3-methylimidazolium chloride [SBMIM]Cl. Over a two hour period, a 20 wt% solution containing up to 43% and 98% of reducing sugars at low temperature in aqueous [SBMIM]Cl was achieved for the starch-based waste and the potato starch, respectively. In addition, the use of microwave and low frequency ultrasound to perform the depolymerisation of the raw starch-based material was explored and compared with conventional heating proc…