Amount Of Na Research Articles

Synthesis of an Ni2P catalyst supported on Na-MCM-41 with highly activity for dibenzothiophene HDS under mild conditions

A novel and simple method to synthesize supported Ni2P/Na(x)-MCM-41 catalysts (where x is the mass fraction of Na-to-MCM-41 in terms of percentage) at a lower reduction temperature by incorporation of Na was described. The catalysts were characterized by H2 temperature-programmed reduction (H2-TPR), X-ray diffraction (XRD), N2 adsorption–desorption, CO uptake, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The effect of Na on the structure of catalysts and catalytic properties for the dibenzothiophene (DBT) hydrodesulfurization (HDS) was investigated, which confirmed that a suitable amount of Na can promote highly dispersed Ni2P particles. The Na preferentially interacts with phosphate to generate the sodium phosphate and therefore suppresses the formation of stronger P–O–P bonds, which enables the phosphide catalyst to be easily formed at a lower reduction temperature. Compared with conventional phosphate (973–1273 K), the reduction temperature of Ni2P/Na(x)-MCM-41 catalyst was relatively low (773 K). The Ni2P/Na(x)-MCM-41 catalyst with x = 1.0 showed the maximum DBT conversion of 91.6%, which is higher than that of Ni2P/M41 without Na (80.3%).

Cu(In,Ga)Se2 surface treatment with Na and NaF: A combined photoelectron spectroscopy and surface photovoltage study in ultra-high vacuum

Either metallic Na or NaF were deposited onto Cu(In,Ga)Se2 surfaces and studied by photoelectron spectroscopy and surface photovoltage spectroscopy without breaking the ultra-high vacuum. The deposition of elemental Na at room temperature led to the formation of an intermediate Cu and Ga rich layer at the CIGSe surface, whereas for NaF the composition of the CIGSe surface remained unchanged. A metal like surface induced by an inverted near surface region with a reduced number of defect states was formed after the deposition of Na. Under the chosen experimental conditions, the near surface layer was independent on the amount of Na and stable in time. In contrast, the usage of NaF weakened the inversion and led to an increased band bending compared to the untreated CIGSe sample. The SPV signals decreased with proceeding time after the deposition of NaF.

Novel Cathode Materials for Sodium Ion Batteries Derived from Layer Structured Titanate Cs<sub>2</sub>Ti<sub>5</sub>O<sub>11</sub>·(1 + x)H<sub>2</sub>O

A layer structured titanate Cs2Ti5O11·(1 + x)H2O (x = 0.70) has been prepared in a solid state reaction using Cs2CO3 and anatase type TiO2 at 900°C. Ion exchange reactions of Cs+ in the interlayer space were studied in aqueous solutions. The single phases of Li+, Na+ and H+ exchange products were obtained. The three kinds of resulting titanates were evaluated for use as the cathodes in rechargeable sodium batteries after dehydrations by heating at 200°C in a vacuum. The electrochemical measurements showed that they exhibited the reversible Na+ intercalation-deintercalation in a voltage range of 0.5 - 3.5 V or 0.7 - 4.0 V. The Li+ exchange product showed the best performance of the discharge-charge capacities in this study. The initial Na+ intercalation-deintercalation capacities of the Li2Ti5O11 were 120 mAh/g and 100 mAh/g; the amounts of Na+ correspond to 1.9 and 1.6 of the formula unit, respectively. The titanates are nontoxic, inexpensive and environmentally benign.

English

The study aimed to determine the effects of humic acid (HA) on seedlings of a salt-sensitive plant, mung bean (Vigna radiata (L.) Wilczek), grown on 50 mM (S1) and 100 mM (S2) NaCl concentrations. In controlled room conditions, mung bean seedlings were planted in pots containing torf and perlite mixture and salt effects were observed. The growth parameters were plant height, number of leaves, leaf area, leaf and stem fresh and dry weights in which all parameters significantly decreased at both salt levels. Nutrient analyses of Na, K and Ca were conducted by flame photometry (FP), and Mg, Mn, Zn were tested by inductively coupled plasma atomic emission spectrometry (ICP-AES), for the above and below ground parts of mung bean seedlings. Both salt treatments increased Na content significantly, however 10 ml addition of HA to those samples (S1HA and S2HA; 50 mM NaCl and 100 mM NaCl, respectively) caused reductions in Na contents of the above-ground parts of mung bean compared to plants watered with only Hoagland-Arnon solutions (HO). On the other hand, in the roots of mung bean seedlings, Na content rose significantly in S2 compared with control, but the amount of Na in S2HA significantly increased compared with S2 treated plants. K content was significantly decreased in both salt concentrations, while SHA1 and SHA2 caused slight increases in both above and underground parts of seedlings. In the experiment, SHA2 increased the content of K, Mg, Ca, Mn and Zn in the root of mung bean seedlings compared with both S1 and S2 treatments. Key words: NaCl, mung bean, growth, nutrient Vigna radiata, humic acid.

Gelatin/montmorillonite biohybrid films prepared via a novel photocrosslinking method: structure–properties investigations

Gelatin/sodium montmorillonite (Na+MMT) hybrid nanocomposite films were prepared by a new photocrosslinking method using 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone (Irgacure 2959) as a photoactive radical initiator and N,N′-Methylenebisacrylamide (MBA) as a crosslinking agent. The prepared samples were characterized by X-ray diffraction (XRD), differential scanning calorimetry, stress–strain measurements and UV–Vis spectrophotometry. XRD patterns showed the formation of exfoliation structure resulting in considerable improves in mechanical properties of the nanocomposite. Retaining of transparency also suggested that Na+MMT nanosheets were uniformly distributed in the gelatin matrix. The tensile strength and Elastic’s modulus of nanocomposites were also improved notably by enhancing amount of Na+MMT. Furthermore, gelatin/Na+MMT nanocomposites showed a second T g at a higher temperature in presence of Na+MMT.

Effects of feeding nucleotides in diets containing corn germ meal or dried corn distillers grains and solubles on the performance and health of receiving and growing calves

To improve profitability of newly arrived stressed feeder cattle, it is essential to minimize feed costs and health issues while optimizing growth performance. Effects of nucleotides (NA; PSB Complex; DSS Global LLC, McCormick, SC) in diets containing corn germ meal (CGM) or dried corn distillers grains with solubles (DDGS) on the health and performance of receiving and growing cattle were analyzed in 3 experiments. In Exp. 1, 213 crossbred heifers (BW 262 ± 67 kg) were used to compare CGM- and DDGS-containing diets and to determine the effects of NA in an 84-d trial. Treatments were a 2 × 3 factorial arrangement: 2 by-product–containing diets (CGM and DDGS) and 3 amounts of NA (0, 2, and 4 g/d). There were no effects of NA, corn by-product, or their interaction on growth performance (P ≥ 0.15). Experiment 2 evaluated performance and immunity effects of NA using 240 crossbred heifers (BW 268 ± 34 kg) in a 56-d trial. The diet contained DDGS, and treatments were 0, 2, and 4 g/d of NA. There were no effects of NA on growth performance (P ≥ 0.18) or fecal IgA concentration (P = 0.15). Experiment 3 used 4 ruminally cannulated Holstein heifers in a 4 × 4 Latin square design. Treatments were arranged as a 2 × 2 factorial: 2 by-product–containing diets (GCM and DDGS) and 2 amounts of NA (0 and 3 g/d). No treatment effects were observed for digestion. Ruminal pH was greater when NA was included (P < 0.05). Based on our results, diets can be formulated to contain 24.5% CGM (DM basis) in place of DDGS and maintain animal performance and digestibility. In our experiments, there was no benefit of supplementing NA in growing diets.

Drivers of Water Transport in Glass: Chemical or Topological Effect of the Glass Network?

The relation existing between water transport in glass, topology, chemical elements (network former and charge compensator), and their structural role in glass were investigated through glass topology modeling, glass and water structure analyses, and water diffusion characterization. Two series of aluminosilicate glasses with and without boron and having various ratios of charge compensators CaO/Na2O were used. The glass structure was characterized using Raman spectroscopy and nuclear magnetic resonance. Their topologies, i.e., the density of bottlenecks and the interstitial sites, were obtained by molecular dynamics. For glasses without boron, the substitution of Na by Ca leads to the strengthening of the glass network. The results are similar for glasses with boron except if the amount of Na is not sufficient. In this case, a part of Ca is required as a charge compensator for AlO4 and BO4 units. This last result is important since it highlights that the presence of boron and the CaO/Na2O ratio drives th...

Cu-exchanged Al-rich SSZ-13 zeolite from organotemplate-free synthesis as NH3-SCR catalyst: Effects of Na+ ions on the activity and hydrothermal stability

The relatively low activity at lower temperatures and high cost of SSZ-13 zeolite from organotemplate synthesis are two of major problems of presently commercialized Cu-SSZ-13 catalysts for NH3-SCR reaction. Cu-exchanged Al-rich SSZ-13 catalysts with Si/Al=4 from organotemplate-free synthesis have been prepared, and show superior NH3-SCR performance with NO conversions above 85% at wide-temperature window ranging from 150 to 650°C. Cu-Na-SSZ-13 catalysts with varied amount of residual Na+ were prepared by partial ion-exchange of as-prepared Al-rich Na-SSZ-13, and it’s found that Cu-Na-SSZ-13 catalyst with moderate Na+ content can improve both the low-temperature activity and its hydrothermal stability. 27Al and 1H MAS NMR spectra indicate that residual Na+ can stabilize the framework Al in Al-rich SSZ-13 zeolite. UV-Vis-NIR and H2-TPR spectra demonstrate that Na+ co-cations enhance the reducibility of Cu2+, whereas too much amount of Na+ may result in the formation of CuOx during the hydrothermal treatment, and further decrease the hydrothermal stability of Cu-Na-SSZ-13 catalyst. The optimized organotemplate-free Cu-Na-SSZ-13 with 2.7wt% Cu and 1.7wt% Na exhibits almost the same NO conversions as the commercial high-silica Cu-SSZ-13 catalyst at 150–550°C after 750 and 800°C hydrothermal aging, and shows promising practical applications.

Abstract MP042: Higher Levels of Sodium Density (mg/kcal) are Associated With Increased Blood Pressure Independent of Absolute Sodium (mg): the DASH Sodium Trial

Introduction: Dietary recommendations for Na are expressed as absolute amounts, that is, mg of Na/d rather than as Na density (mg/kcal). The DASH-Na dose-response trial tested the impact of varying Na density on BP, that is, the absolute dose of Na received at the low, medium, and high levels depended on energy intake. For example, a dose of 3,600 mg was high density in individuals with average energy intake but was medium density in individuals with higher energy intake. Objective: Evaluate whether the effect of Na density on BP was independent of absolute Na. Methods: In the DASH-Na trial, participants with pre-or stage 1 hypertension were randomly assigned to a control or DASH diet; on both diets, participants were fed each of three Na levels in random order. We analyzed data from 378 Non-Hispanic Black and White participants (ages 23-76 yr, baseline BP 135/86). Using a mixed effects model, level of Na density (low, medium, or high) was added to a model of absolute Na on BP to determine if the effect of Na density on BP was independent of absolute Na, with adjustment for randomized diet, cohort, carryover, clinical center, age, sex, race, and interactions of diet with absolute Na and Na density. Results: At the same absolute amount of Na, higher Na density was associated with higher SBP and DBP (both p&lt;0.0001) in the control diet arm (Figure 1). At the recommended upper limit of Na (2300 mg), the average SBP and DBP of those on a medium-Na-density diet was 7.2 mmHg (95% CI: 4.8, 9.7) and 3.9 mmHg higher (95% CI: 2.3, 5.5), respectively, than those on a low-Na-density diet. At 3600 mg, the average SBP and DBP of those on a high-Na-density diet was 6.0 mmHg (95% CI: 3.6, 8.5) and 3.1 mmHg (95% CI: 1.5, 4.7) higher, respectively, than those on a medium-Na-density diet. These differences were somewhat smaller, but still significant, in the DASH diet arm. Conclusions: The effects of Na on BP vary with energy needs. This suggests that Na density should be considered when designing and interpreting studies of Na and BP and when providing dietary guidance.

High-Salt Diet Causes Osmotic Gradients and Hyperosmolality in Skin Without Affecting Interstitial Fluid and Lymph.

The common notion is that the body Na+ is maintained within narrow limits for fluid and blood pressure homeostasis. Several studies have, however, shown that considerable amounts of Na+ can be retained or removed from the body without commensurate water loss and that the skin can serve as a major salt reservoir. Our own data from rats have suggested that the skin is hypertonic compared with plasma on salt storage and that this also applies to skin interstitial fluid. Even small electrolyte gradients between plasma and interstitial fluid would represent strong edema-generating forces. Because the water accumulation has been shown to be modest, we decided to reexamine with alternative methods in rats whether interstitial fluid is hypertonic during salt accumulation induced by high-salt diet (8% NaCl and 1% saline to drink) or deoxycorticosterone pellet implantation. These treatments resulted both in increased systemic blood pressure, skin salt, and water accumulation and in skin hyperosmolality. Interstitial fluid isolated from implanted wicks and lymph draining the skin was, however, isosmotic, and Na+ concentration in fluid isolated by centrifugation and in lymph was not different from plasma. Interestingly, by eluting layers of the skin, we could show that there was an osmolality and urea gradient from epidermis to dermis. Collectively, our data suggest that fluid leaving the skin as lymph is isosmotic to plasma but also that the skin can differentially control its own electrolyte microenvironment by creating local gradients that may be functionally important.

Swelling pressure and leaching behaviors of synthetic bituminized waste products with various salt contents under a constant-volume condition

ABSTRACTWe investigated the swelling pressure of synthetic bituminized waste products (BWPs) and the amount of Na+ in the leachate from them under a constant-volume condition when the BWPs were in contact with water to understand influences of salt content on the surrounding environments after disposal of radioactive BWPs in a geological repository. The observation of the cross section of the synthetic BWP specimens revealed that micropores, which were formed after soluble salts leached out from the specimens, shrank and deformed near the surface of the specimens. The salt content in the synthetic BWP specimens depended on the amount of water taken up, indicating that an increase in the amount of water led to increases in the swelling pressure and the cumulative amount of Na+ in the leachate. It was found that the shrinkage and deformation of the micropores near the surface of the synthetic BWP specimens that arose under the constant-volume condition significantly influenced increases in the swelling pressure and cumulative amount of Na+ in the leachate.

Plant ionic relation and whole-plant physiological responses to waterlogging, salinity and their combination in barley.

Waterlogging and salinity stresses significantly affect crop growth and global food production, and these stresses are often interrelated because waterlogging can lead to land salinisation by transporting salts to the surface. Although the physiological and molecular mechanisms of plant responses to each of these environmental constraints have been studied in detail, fewer studies have dealt with potential mechanisms underlying plant tolerance to the combined stress. This gap in knowledge is jeopardising the success of breeding programs. In the present work we studied the physiological and agronomical responses of 12 barley varieties contrasting in salinity stress tolerance to waterlogging (WL), salinity (NaCl) and combined (WL/NaCl) stresses. Stress damage symptoms were much greater in plants under combined WL/NaCl stress than those under separate stresses. The shoot biomass, chlorophyll content, maximum photochemical efficiency of PSII and shoot K+ concentration were significantly reduced under WL/NaCl conditions, whereas shoot Na+ concentration increased. Plants exposed to salinity stress showed lower damage indexes compared with WL. Chlorophyll fluorescence Fv/Fm value showed the highest correlation with the stress damage index under WL/NaCl conditions (r=-0.751) compared with other measured physiological traits, so was nominated as a good parameter to rank the tolerance of varieties. Average FW was reduced to 73±2, 52±1 and 23±2 percent of the control under NaCl, WL and combined WL/NaCl treatments respectively. Generally, the adverse effect of WL/NaCl stress was much greater in salt-sensitive varieties than in more tolerant varieties. Na+ concentrations of the shoot under control conditions were 97±10µmolg-1 DW, and increased to 1519±123, 179±11 and 2733±248µmolg-1 under NaCl, WL and combined WL/NaCl stresses respectively. K+ concentrations were 1378±66, 1260±74, 1270±79 and 411±92µmolg-1 DW under control, NaCl, WL and combined WL/NaCl stresses respectively. No significant correlation was found between the overall salinity stress tolerance and amount of Na+ accumulated in plant shoots after 15 days of exposure to 250mM NaCl stress. However, plants exposed to combined salinity and WL stress showed a negative correlation between shoot Na+ accumulation and extent of salinity damage. Overall, the reported results indicate that K+ reduction in the plants under combined WL/NaCl stress, but not stress-induced Na+ accumulation in the shoot, was the most critical feature in determining the overall plant performance under combined stress conditions.

Aerosol Hygroscopic Growth as a New Factor for Trace and Ultra-Trace Determination of Phosphorous in Flame Containing Optical Trapping-Cavity Ring-Down Spectroscopy

A new method has been introduced based on aerosol hygroscopic growth as a new factor for trace and ultra-trace determination of phosphorous in flame containing optical trapping-cavity ring down aerosol extinction (emission) spectrometer (OT-CRD-AES). In this study, a cavity ring down has been designed using hydrogen and air as fuel and oxidant during introduction of the aerosols containing phosphorous species using an ultrasonic generator (humidifier) from an acidic solution by a flow rate of N2 , followed by detection of the Mie scattering using a charged coupling device (CCD) system. Parameters having strong influence during following scattering of the aerosols during their hygroscopic growth inside the humidified flame (H2 /air), include: influence and amount of Na+ as radiation buffer (as light source), flow rates of H2 , air and N2 , kind and concentrations of acid, evaluation of the aerosols inside flame, etc. These parameters were optimized using simplex and one at a time methods. Based on the figures of merit under optimized condition, two linear calibration curves with reverse slopes were evaluated between 10.0 - 250.0 ng mL-1 and 1.0 - 20.0 µg mL-1 with correlation coefficients (R2 ) the same as 0.999 and 0.998, respectively. The calibration sensitivities were also estimated to 57.46 and 0.348 (a.u), respectively, with detection limit of 5.0 ng mL-1. The mechanism of the radiation (Mie scattering) was also evidenced based on i) dependency of the scattered radiations to the quantity of an alkali ions such as Na+ as well as the humidity, ii) presence of acceptable correlation between the response of the cavity with turbidometry, iii) observation of blue shift from green (color related to the luminescence of HPO* in H2 /air flame) to blue (scattered radiation) and finally iv) effect of hydration number during stability and growth of the aerosols inside the flames. No serious interference was evaluated during analysis of at least 500-fold excess of various foreign species. However, the only observed interference was evaluated during introduction of 200-fold excess of SO4 2-. Good correlation was also evaluated between the results obtained from this technique and ion exchange chromatography during analysis of wastewater samples that clearly revealed the reliability of this method for phosphorous detection and determination at µg mL-1 and ng mL-1 levels.

Empirical Study of Treatment of Sour Gas by New Technology

The use of multistage, fluidized beds of continuous recycles reveals economically and technically attractive for both adsorption of stack gas SO2 and sequential conversion to elemental sulfur. This paper studies the adsorption process behavior of SO2 removal in one bed reactor which is filled with zinc oxide nano catalysts. The performance of catalytic bed is analyzed experimentally and theoretically by measuring the rate of mass transfer, NA, in this work. Sulfur elimination from gas is the major purpose of the handled experiments. The specific surface area (15, 20 and 25 m2/m3) as a effective parameter on mass transfer area and the particle diameter (40, 60 and 80 nm) as feed driving force on the amount of NA are evaluated.

P2-Type NaxCu0.15Ni0.20Mn0.65O2 Cathodes with High Voltage for High-Power and Long-Life Sodium-Ion Batteries.

Cu-Ni-Mn-based ternary P2-type NaxCu0.15Ni0.20Mn0.65O2 (x = 0.50, 0.67, and 0.75) cathodes for sodium-ion batteries (SIBs) are synthesized by a co-precipitation method. We find that Na content plays a key role on the structure, morphology, and the charge-discharge performances of these materials. For x = 0.67 and 0.75, superstructure from Na+-vacancy ordering is observed, while it is absent in the x = 0.50 sample. Despite the same synthesis conditions, materials with x = 0.67 and 0.75 show smaller particle sizes compared to that of the x = 0.50 sample. In addition, redox potentials of the materials differ significantly even though they have the same transition metal ratios. These differences are attributed to the changes in local structures of the as-prepared materials arising from the different amount of Na and possibly oxygen in the lattice. Materials with x = 0.67 and 0.75 show excellent rate performance and cycle stability when tested as cathode material of SIBs. Average discharge potential is as high as 3.41 V versus Na-Na+ with capacity of 87 mAh g-1 at 20 mA g-1. Excellent capacity and cycle stability are maintained even when they are tested with higher current rates. For instance, a capacity of 62.3 mAh g-1 is obtained from the x = 0.67 sample at 1000 mA g-1 after 1000 cycles between 3.0 and 4.2 V without any decrease in capacity.

Methyl Methacrylate and Alpha-Methyl Styrene: New Strategy for Synthesis of Bloc Copolymers for Use in Potential Biomedical Applications Generated by an Ecologic Catalyst Called Maghnite (Algerian MMT)

A new model for synthesis of the plastics, block copolymers were prepared from methyl methacrylate (MMA) and alpha-methyl styrene (α-MS) by cationic copolymerization in the presence of a new and efficient catalyst of “Maghnite-Na” at 0 °C in bulk. In this paper, the copolymerization of α-MS and MMA was induced in heterogeneous phase catalyzed by Maghnite-Na was investigated under suitable conditions. The “Maghnite-Na” is a montmorillonite sheet silicate clay, with exchanged sodium cations to produce Na-Montmorillonite (Na+-MMT) obtained from Tlemcen, Algeria, was investigated to remove heavy metal ion from wastewater as an efficient catalyst for cationic polymerization of many vinylic and heterocyclic monomers. The synthesized copolymer were characterized by Nuclear Magnetic Resonance (NMR-1H, NMR-13C), FT-IR spectroscopy, Differential Scanning Calorimetry (DSC), and Gel Permeation Chromatography (GPC) to elucidate structural characteristics and thermal properties of the resulting copolymers. The structure compositions of “MMT”, “H+-MMT” and “Na+-MMT” have been developed. The effect of the MMA/α-MS molar ratio on the rate of copolymerization, the amount of catalyst, temperature and time of copolymerization on yield of copolymers was studied. The yield of copolymerization depends on the amount of Na+-MMT used and the reaction time. The kinetic studies indicated that the polymerization rate is first order with respect to monomer concentration. A possible mechanism of this cationic polymerization is discussed based on the results of the 1H-NMR Spectroscopic analysis of these model reactions. A cationic mechanism for the reaction studies showed that monomer was inserted into the growing chains.

Investigation into the origin of high stability of δ-MnO2 pseudo-capacitive electrode using operando Raman spectroscopy

Abstract Manganese oxides of different structures, especially α-MnO2, have been extensively studied as electrodes for pseudocapacitors. However, the poor stability associated with intercalation of proton has been the main obstacle to their commercial applications. To effectively mitigate this problem, it is necessary to fully understand the energy storage mechanism of the MnO2 phases. In this study, δ phase MnO2 has been synthesized through controllable electroplating on architectural Ga-doped ZnO (GZO) bones, demonstrating a high specific capacitance of 1068 F g−1 and high stability (slight performance drop focus on the first 2000 cycles and then remained relatively constant in the subsequent 13,000 cycles). The charge storage mechanism of the δ-MnO2 coated GZO has been carefully investigated under this extreme reaction condition. Results suggest that the amount of charge stored in the electrode material correlates well with the amount of Na+ inserted into the electrode material from the electrolyte. It is also noted that no spectral features corresponding to H+ insertion were detected during cycling when the sample was probed using in operando Raman spectroscopy. Therefore, for layered δ-MnO2, a charge storage mechanism of Na+ intercalation/deintercalation dominated, accompanied by interlayer spacing expansion/contraction, was proposed. Moreover, theoretical calculations also confirmed that the insertion of Na+ is more energetically favorable than H+ at all sites of the interlayer in δ-MnO2, offering a rational explanation of the proposed mechanism and the observed excellent stability.

MnO2 for Supercapacitors

MnO2 have attracted large attention as a supercapacitor material due to its high theoretical specific capacitance, low cost, natural abundance, easy preparation and environmental friendliness. Among the various polymorphs of MnO2, the 2D layered birnessite has shown promising charge storage capability1–3. In this work, Na-doped birnessite and hausmannite were synthesized by a redox reaction between Mn2+ and MnO4 - in a NaOH solution. The resulting precipitate was aged for one or seven days. The powders were characterized by XRD, BET and SEM. Electrodes were composed of MnO2, activated carbon (AB) and PTFE with the weight ratio 75:15:10. The MnO4 -/Mn2+-ratio and the synthesis temperature were found to determine the composition (i.e. the relative amounts of birnessite and hausmannite) and the ageing time determined the crystallinity. The XRD (see Fig. 1a) shows that the material denoted Mn3O4 is very well crystallized hausmannite. MnO2-A is a birnessite with low crystallinity, while MnO2-B consists of crystalline birnessite with some hausmannite. MnO2-C is more crystalline than MnO2-B. Both MnO2-A and MnO2-B have a surface area of 42.5 m2/g. Cyclic voltammograms measured at 5 mV/s between -0.05 and 0.85 V vs. Ag/AgCl in 1M Na2SO4 are shown in Fig. 1b. The specific capacitance of MnO2-A was 169 F/g at 5 mV/s with a capacitance retention of 92.5 % at 5 mV/s after 2000 cycles at 100 mV/s. The specific capacitance of MnO2-B was found to be 118 F/g at 5 mV/s with an increase to 129 F/g at 5 mV/s (109 % of the original capacitance) after 2000 cycles at 100 mV/s. The capacitance increase could be due to dissolution and redeposition of MnO2 4. The capacitance of MnO2-A is higher than the capacitance of MnO2-B despite equal surface areas. The CV curves show interesting redox waves and peaks. The shape of the CV curve for MnO2-A resembles CV curves reported for poorly crystallized birnessite1. The redox waves were assigned to cation and proton deintercalation upon oxidation and intercalation upon reduction. The CV curve for MnO2-B exhibit pronounced redox peaks, which are previously observed for well crystallized birnessites5, 6. Two anodic peaks and two cathodic peaks were reported. These peaks were related to proton and cation intercalation and deintercalation at two different sites in the interlayer space of the birnessite5– 7. The peaks have also been attributed to redox transitions between different valence states of Mn8. The reaction mechanisms and the degradation mechanisms will be further investigated by EQCM and EIS. The amount of Na+ in the materials will be determined by ICP. The most crystalline material (MnO2-C) and Mn3O4 will be tested. In addition, the electrochemical performance of the materials in different electrolytes (Li2SO4, K2SO4, MgSO4, LiOH) will be studied.

Abstract P636: Insulin Resistance in Obesity Results in Postprandial Salt and Water Loss

Obesity and insulin resistance contribute to the development of metabolic syndrome, a growing epidemic in our country. The obese Zucker rat is an experimental model of this disease. Previously, using Sprague Dawley rats, we have shown that the normal postprandial rise in insulin acts physiologically to prevent renal salt and water wasting after meals. This study tested whether the effects of postprandial insulin would be attenuated in insulin resistant rats and result in excess salt and water loss. Chronic artery and vein catheters were implanted in male lean and obese Zucker rats for infusion and blood sampling. Rats were housed in metabolic cages and their catheters were connected to dual-channel Instech swivels for access. Over a 24-hr period of ad libitum eating, blood glucose was not different between obese and lean rats (127±7 vs. 120±3 mg/dl) but obese rats were hyperinsulinemic (14.86 vs. 0.98 ng/ml). Obese rats had significantly greater urine volume than lean controls (22.5±1.2 vs. 14.7±0.9 ml) despite similar water intakes. Obese rats tended to excrete more Na+ than lean controls (3.46±0.15 vs. 2.97±0.35 mEq) with equal amounts of Na+ intake. To evaluate the response to a single meal while controlling for blood glucose, fasted rats were administered a glucose bolus (as 50% dextrose) that yielded peak levels of blood glucose that were not different in the two groups (589±11 vs. 596 ±3 mg/dl at t=5 min.). Plasma insulin increased from fasting in both groups to 26.35 and 9.34 ng/ml in obese and lean controls, respectively. Over the 4-hour period following the glucose administration, obese rats had significantly greater urine volume (8.6±1.3 vs. 2.2 ±0.6 ml) and Na+ excretion (0.53±0.11 vs. 0.25±0.09 mEq) than lean controls. This suggests that insulin resistance of obesity may impair the ability of postprandial insulin to participate in maintenance of Na+ and water homeostasis, but the potential role of insulin resistance specifically within the kidney requires further study.

Applicability of polyvinylpolypyrrolidone adsorbent to treatment process of wastes containing uranium

In order to assess the feasibility of method for recovering U from wastes containing uranium (scrap uranium) using polyvinylpolypyrrolidone (PVPP) adsorbent, we have examined the adsorption and desorption behavior of metal species in HCl aqueous solutions dissolving scrap uranium. It was found that the U(VI) species are selectively adsorbed onto PVPP regardless of the presence of a large amount of Na(I) and Al(III), that the adsorbed U(VI) species are desorbed from PVPP column selectively by water. From these results, the PVPP resin is expected to be used as the adsorbent in the treatment process of scrap uranium.