Search results for "Ion-Exchange"
showing 10 items of 64 documents
Thermal potential of ion-exchange membranes and its application to thermoelectric power generation
2016
The low efficiency and high price of thermoelectric semiconductors has generated interest in unconventional forms of thermoelectric materials. In this article, ionic thermoelectricity has been studied with commercial ion-exchange membranes for different aqueous 1:1 electrolytes. The theory of thermal membrane potential has been derived taking into account the ionic heats of transport, the non-isothermal Donnan potentials, the temperature polarization, and the thermally-induced concentration polarization of the electrolyte. Also the generated thermoelectric power has been experimentally studied. The experiments show good agreement with the theory, and suggest ways for systematic improvement …
Response of Vertisols, Andosols, and Alisols to paddy management
2016
Abstract Interchanging submergence and drainage in paddy soils induce alternating redox conditions. It is known that this causes changes in organic carbon stocks, in amounts and crystallinity of Fe oxides as well as transformation of clay minerals and subsequent changes in cation exchange capacity (CEC). However, the influence of the initial soil type on the extent of these changes is not yet well understood. Therefore, we studied paddy soils that derived from three different soil types (Vertisols, Andosols, Alisols) on volcanic parent material in Java (Indonesia). To account for the variability in parent materials, we additionally sampled sandstone-derived Alisols in China. Adjacent non-pa…
HPLC determination of volatile phenols in wines
1993
An alternative to the traditional solvent extraction method used to extract and rapidly quantify ethyl-and vinylphenol and ethyl-and vinylgaiacol from wine is presented. The method is based on retention of volatile phenols on adsorbants. Among the tested resins, the most efficient, AG 2-X8 (anion exchange resin), worked as well with a synthetic solution as with wines. The percolation of clarified wine adjusted to pH 9 on this resin permits, in particular, the elimination of organic acids. Phenols are not eluted after rinsing the column with 1N HCl, but are eluted with methanol after this treatment. Good recovery (91 %) and good repeatability are observed. The eluate is directly analysed by …
Hochleistungsfl�ssigchromatographische Bestimmung von organischen S�uren, Zuckern, Glycerin und Alkohol im Wein an einer Kationenaustauschers�ule
1985
Mit der HPLC ist es moglich, die wichtigsten Bestandteile von Wein (Ethanol, Glycerin, Glucose, Fructose, Tartrat, Malat, Lactat, Succinat, Acetat und Citrat) in einem Lauf innerhalb von 25 min zu trennen und quantitativ zu bestimmen. Als stationare Phase dient der Kationenaustauscher HPX 87 H und als mobile Phase verdunnte Schwefelsaure. Die Untersuchungsergebnisse an einigen Weinen werden dargestellt. Es besteht eine gute Ubereinstimmung zwischen den Analysenergebnissen der HPLC und herkommlichen Methoden.[/p]
Energy harvesting by waste acid/base neutralization via bipolar membrane reverse electrodialysis
2020
Bipolar Membrane Reverse Electrodialysis (BMRED) can be used to produce electricity exploiting acid-base neutralization, thus representing a valuable route in reusing waste streams. The present work investigates the performance of a lab-scale BMRED module under several operating conditions. By feeding the stack with 1 M HCl and NaOH streams, a maximum power density of ~17 W m−2 was obtained at 100 A m−2 with a 10-triplet stack with a flow velocity of 1 cm s−1, while an energy density of ~10 kWh m−3 acid could be extracted by a complete neutralization. Parasitic currents along feed and drain manifolds significantly affected the performance of the stack when equipped with a higher number of t…
Pd-Cu catalysts supported on anion exchange resin for the simultaneous catalytic reduction of nitrate ions and reductive dehalogenation of organochlo…
2019
International audience; The present work proposes the simultaneous removal of these classes of pollutants by a catalytic hydrotreatment processes. For this purpose, bimetallic Pd-Cu catalysts (with mass ratio Pd:Cu of 4:1) supported on macroporous strong base anion resin were prepared by different methods. The catalysts were characterized (by XRD, SEMEDX, XPS, AAS and H-2 chemisorption) and tested in a continuous flow system. The selected catalyst preparation protocol consists in a two-step method, which implies the deposition of palladium by ion exchange and the subsequent deposition of copper by controlled reaction on the surface of the pre-reduced palladium. The effectiveness of the cata…
Comparative study for separation of aquatic humic-type organic constituents by DAX-8, PVP and DEAE sorbing solids and tangential ultrafiltration: ele…
2005
Aquatic humic-type solutes were separated in parallel from the same fresh water source by four different procedures: non-ionic polymethyl methacrylate (DAX-8) and functional cross-linked polyvinylpyrrolidone (PVP) resins, functional diethylaminoethyl cellulose (DEAE) and tangential ultrafiltration completed with a weakly basic anion exchange resin (IRA-67). The similarity-dissimilarity between the quantities and qualities of the different humic samples is discussed, especially in the light of the original dissolved organic matter (DOM). During the past two decades, a significant progress has occurred in the aquatic humic research due to the so-called hydrophobic-hydrophilic properties posse…
Influence of inheritance and pedogenesis on heavy metal distribution in soils of Sicily, Italy
2000
Abstract The recognition of the potential health hazards associated with heavy metals has focused attention on the levels and behaviours of these elements both in natural and contaminated environments. Various soil types developed from different parent materials in Sicily, Italy, have been analysed in order to compare heavy metal distribution under different geopedological conditions. Total metal concentrations, metal partitioning and distribution profiles are discussed in relation to the inheritance factor and pedogenic processes. Parent material composition largely influences the contents of heavy metals in most of the analysed soils, mainly differentiating pedons for their metal concentr…
Post-Processing via Cation Exchange Cartridges: Versatile Options
2012
New 68Ge/68Ga radionuclide generators provide the positron emitter 68Ga (T½ = 67.7 min) as an easily available and relatively inexpensive source of a PET nuclide for labeling of interesting targeting vectors. However, currently available “ionic” 68Ge/68Ga radionuclide generators are not necessarily optimized for the routine synthesis of 68Ga-labeled radiopharmaceuticals in a clinical environment. Post-processing of 68Ge/68Ga generators using cation exchange resins provides chemically and radiochemically pure 68Ga with 97±2% within less than 4 min, with 68Ge almost completely removed, and ready for online labeling. This simple, fast, and efficient technology can be extended for new applicati…
1992
Phosphonomethyl-substituted phenols are readily obtained from o-hydroxymethylated phenols and trialkyl phosphites. The free acids, incorporated into phenol-formaldehyde resins, act as cation exchangers with remarkable selectivity for different metal ions.