Mixture Of HNO3 Research Articles

Yield and mineral composition of seeds of leguminous plants and grain of spring wheat as well as their residual effect on the yield and chemical composition of winter oilseed rape seeds

A controlled field experiment was carried out in 2011-2014 in order to determine yields and chemical composition of selected genotypes of leguminous plants and spring wheat, as well as their value as a preceding crop (crop volume, mineral composition of seeds) for winter oilseed rape grown in Northern Poland. Chemical analysis of the content of macronutrients and micronutrients in seeds and grain was conducted using standard methods after mineralisation in H2SO4 with H2O2 as an oxidant (macronutrients), or in a mixture of the acids HNO3+HCl+HClO4 (micronutrients). It was proven that among the examined species and seasonal types of legumes, the highest total seed and protein yield volume was obtained from both field bean forms, traditional and determinate one. The lowest yield was achieved from blue lupine. The yield of winter wheat grain oscillated around 5.6 t ha-1. Blue lupine seeds were characterised by the highest total protein content. Seeds of both field bean forms were distinguished by the highest content of potassium, phosphorus, copper and zinc, while blue lupine seeds had the highest content of calcium, magnesium and manganese. The research showed a clear tendency towards a higher winter oilseed rape yield in a field after determinate field bean and seed pea. Spring wheat proved to be the worst previous crop for winter oilseed rape. The tendency for greater accumulation of nitrogen, phosphorus, calcium, copper, iron and zinc in winter oilseed rape seeds was observed in a field after determinate field bean. The lowest content of macronutrients and micronutrients was characteristic for seeds of winter oilseed rape grown after spring wheat. Winter oilseed rape seeds in a field after determinate field bean and blue lupine were rich in prof. dr hab. Gabriel Fordonski, Chair of Entomology, Phytopathology and Molecular Diagnostics, University of Warmia and Mazury in Olsztyn, Pl. Łodzki 5,10-727 Olsztyn, Poland, e-mail: gabriel.fordonski@uwm.edu.pl * This study was supported with funds of the Polish Ministry of Agriculture and Rural Development under the project No.HOR. 3.3.3.

Use of Hydrofluoric Acid Desilicification in the Determination of Highly Siderophile Element Abundances and Re‐Pt‐Os Isotope Systematics in Mafic‐Ultramafic Rocks

Properly combining highly siderophile element (HSE: Re, Pd, Pt, Ru, Ir, Os) abundance data, obtained by isotope dilution, with corresponding 187Os/188Os and 186Os/188Os measurements of rocks requires efficient digestion of finely‐ground powders and complete spike‐sample equilibration. Yet, because of the nature of commonly used methods for separating Os from a rock matrix, hydrofluoric acid (HF) is typically not used in such digestions. Consequently, some silicates are not completely dissolved, and HSE residing within these silicates may not be fully accessed. Consistent with this, some recent studies of basaltic reference materials (RMs) have concluded that an HF‐desilicification procedure is required to fully access the HSE (Ishikawa et al. (2014) Chemical Geology, 384, 27–46; Li et al. (2015) Geostandards and Geoanalytical Research, 39, 17–30). Highly siderophile element abundance and Os isotope studies of intraplate basalts typically target samples with a range of MgO contents (< 8 to > 18% m/m, or as mass fractions, < 8 to > 18 g per 100 g), in contrast to the lower MgO mass fractions (< 10 g per 100 g) of basalt and diabase RMs (i.e., BIR‐1, BHVO‐2, TDB‐1). To investigate the effect of HF‐desilicification on intraplate basalts, experiments were performed on finely ground Azores basalts (8.1–17 g per 100 g MgO) using a ‘standard acid digestion’ (2:1 mixture of concentrated HNO3 and HCl), and a standard acid digestion, followed by HF‐desilicification. No systematic trends in HSE abundances were observed between data obtained by standard acid digestion and HF‐desilicification. Desilicification procedures using HF do not improve liberation of the HSE from Azores basalts, or some RMs (e.g., WPR‐1). We conclude that HF‐desilicification procedures are useful for obtaining total HSE contents of some young lavas, but this type of procedure is not recommended for studies where Re‐Pt‐Os chronological information is desired. The collateral effect of a standard acid digestion to liberate Os, followed by HF‐desilicification to obtain Re and Pt abundances in samples, is that the measured Re/Os and Pt/Os may not correspond with measured 187Os/188Os or 186Os/188Os.

Determination of uranium in seawater, biological samples and sediments using laser induced fluorescence spectrometry

Uranium has been determined in seawater, biological samples and sediments using laser induced fluorescence spectrometry (LIFS). The biological samples and sediments are digested with a mixture of HNO3, HClO4 and HF. The conductivity of the seawater should be below 5.0 mS and the pH of the sample should be in the range 6.5–9.0. The volume of the reagent used to enhance the fluorescence intensity was 0.5 ml. Comparison with other methods was favorable, LIFS being rapid, simple and sensitive, and well suited to environmental monitoring.

High precision zinc isotopic measurements applied to mouse organs.

We present a procedure to measure with high precision zinc isotope ratios in mouse organs. Zinc is composed of 5 stable isotopes ((64)Zn, (66)Zn, (67)Zn, (68)Zn and (70)Zn) which are naturally fractionated between mouse organs. We first show how to dissolve the different organs in order to free the Zn atoms; this step is realized by a mixture of HNO3 and H2O2. We then purify the zinc atoms from all the other elements, in particular from isobaric interferences (e.g., Ni), by anion-exchange chromatography in a dilute HBr/HNO3 medium. These first two steps are performed in a clean laboratory using high purity chemicals. Finally, the isotope ratios are measured by using a multi-collector inductively-coupled-plasma mass-spectrometer, in low resolution. The samples are injected using a spray chamber and the isotopic fractionation induced by the mass-spectrometer is corrected by comparing the ratio of the samples to the ratio of a standard (standard bracketing technique).This full typicalprocedure produces an isotope ratio with a 50 ppm (2 s.d.) reproducibility.

Microstructural evolution of ultrafine-grained NiCrCoAl foil after heat treatment at 1000°C

This research investigated the microstructural evolution of Ni–23·5Cr–2·66Co–1·44Al superalloy foil fabricated by electron-beam physical vapour deposition and annealed at 1000°C. The results showed that the deposited alloy mainly consisted of the γ-phase. After annealing at 1000°C, the peak moved to a lower 2θ degree on the deposited side and to a higher 2θ degree on the substrate side, which indicated that uniform strain existed at the deposited state and recovery occurred during annealing. With an increase in the annealing time, the (220) diffraction peak increased significantly. The average size of the grains increased and showed zigzag structures after being etched by a mixture of HNO3, HCl and HF etchant. After being annealed at 1000°C for 4 hours, the ultimate tensile strength of the Ni–23·5Cr–2·66Co–1·44Al superalloy foil was improved from 641 to 800 MPa.

The role of oxygen functional groups in the adsorption of heteroaromatic nitrogen compounds

A wood-based activated carbon (AC) was oxidized using different oxidants. The resultant adsorbents were applied to adsorb nitrogen (N) containing compounds that appeared in light cycled oil. Appropriate oxidation treatment can increase oxygen functional groups on the surface of AC without much damage to its pore structure. Oxygen functional groups play a key role in enhancing adsorptive selectivity of carbons. Lactone groups can facilitate the selective removal of 1-ring N compounds. Phenolic groups, total CO2-releasing groups and total O groups show an improvement in the adsorption of 2-ring N compounds. Aldehyde groups favor the adsorption of 3-ring and 4-ring N compounds. However, excessive oxidation can result in the collapse of pore structure and closure of pore channels. For instance, the carbon oxidized by a mixture of concentrated H2SO4 and HNO3 has an extremely low adsorption performance.

Syntheses and Crystal Structures of New ReO3‐Type‐Derived Transition Metal Oxide Fluorides

AbstractMixed‐metal oxide fluorides MNb2O3F6 (M = Mg, Zn), MgM2OF8 (M = Ti, Zr), Fe2TiO8F, and TiNb2O5F4 were prepared by treatment of their corresponding oxides with a 1:1 mixture of hydrofluoric acid and HNO3. Crystal structures were investigated by means of X‐ray powder diffraction. The anion distribution of MgZr2OF8 was studied theoretically. MNb2O3F6‐type compounds can be structurally refined in the cubic ReO3 type, MgTi2OF8,and MgZr2OF8 in the cubic NaSbF6 type, Fe2TiOF8 in the rhombohedral VF3 type. All presented oxide fluorides are colorless powders and the metal ions are in the highest formal valence state.

Preparation and characterization of functionalized graphite/poly(butylene terephthalate) composites

Poly(butylene terephthalate)/graphite (PBT/GP) composites were prepared using a melt-mixing method. To enhance the compatibility between PBT and GP, acrylic acid-grafted PBT (PBT-g-AA) and multi-hydroxyl-functionalized graphene oxide (GO-OH) were used to replace PBT and GP, respectively. Composites of PBT/GP or PBT-g-AA/GO-OH were prepared with 0, 1, 3, and 5 wt% inorganic filler (GP or GO-OH) contents. Crude graphene oxide (GO) was oxidized chemically using a mixture of H2SO4 and HNO3 and then reacted with thionyl chloride to functionalize it with chlorocarbonyl groups (GO-COCl). GO-OH was obtained from the reaction of graphene oxide (GO)-COCl with ethylene glycol. The composites were characterized morphologically by transmission electron microscopy. The PBT-g-AA/GO-OH was also characterized by FTIR spectra, 13C solid-state NMR spectra, UV–Vis spectra, TEM micrographs, DSC analysis, TGA analysis and Electrical conductivity. The PBT-g-AA/GO-OH (3 wt%) composites had significantly improved thermal properties. The functionalized PBT-g-AA/GO-OH composite showed markedly enhanced anti-static properties. The optimal proportion of GO-OH in the composites was 3 wt%. In excess of this amount, the compatibility between the organic and inorganic phases was compromised.

Nanoporous carbons from oxidized green needle coke for use in high performance supercapacitors

Green needle coke was oxidized by a mixture of HNO3 and H2SO4 (3:7 vol/vol) acids. The resultant oxidized coke was separated into water dispersible and non-dispersible fractions, which were then activated by KOH using the same KOH/coke weight ratio to obtain two kinds of nanoporous carbons with different pore structures. The oxidized coke and the nanoporous carbons were characterized by XPS, XRD, TEM, N2 adsorption and electrochemical tests. Results indicate that, at the same KOH/coke ratios, the nanoporous carbons derived from the water-dispersible oxidized coke have higher mass specific capacitances and capacitance retention ratios, and lower resistances than those from the non-dispersible ones when used as an electric double layer capacitor electrode in 6 mol/L KOH, but the former have a lower volumetric specific capacitance than the latter.

Synthesis and characterization of Pt supported on multiwalled carbon nanotubes for improved catalytic performance in fuel cell applications

Commercially available multiwalled carbon nanotubes (MWCNTs) were functionalized using a mixture of HNO3 and H2SO4 in refluxing condition under three different reaction times (1, 3, and 5 h). The Pt loaded on functionalized MWCNTs (f-MWCNTs) (Pt/1f, 3f & 5f-MWCNTs) were prepared by reducing chloroplatinic acid and for comparison Pt loaded on pristine MWCNTs (Pt/MWCNTs) was also prepared. The size of Pt nanoparticles was determined using X-ray diffraction method. The uniform dispersion of the Pt catalyst on CNTs was confirmed by HRSEM and HRTEM. Surface area and pore size were calculated by Brunauer Emmett Teller analysis method. Five membrane electrode assembly sets were prepared (Pt/MWCNTs, Pt/1f, 3f, 5f-MWCNTs and commercial Pt/C) and tested in the fuel cell assembly. The first four were prepared using SPEEK membrane as electrolyte with the synthesized Pt/f-MWCNTs catalysts and the fifth one was prepared using commercial Nafion-117 electrolyte and Pt/C electrode for comparison.

A facile enzymatic synthesis of geranyl propionate by physically adsorbed Candida rugosa lipase onto multi-walled carbon nanotubes

In view of several disadvantages as well as adverse effects associated with the use of chemical processes for producing esters, alternative techniques such as the utilization of enzymes on multi-walled carbon nanotubes (MWCNTs), have been suggested. In this study, the oxidative MWCNTs prepared using a mixture of HNO3 and H2SO4 (1:3 v/v) were used as a supportive material for the immobilization of Candida rugosa lipase (CRL) through physical adsorption process. The resulting CRL-MWCNTs biocatalysts were utilized for synthesizing geranyl propionate, an important ester for flavoring agent as well as in fragrances. Enzymatic esterification of geraniol with propionic acid was carried out using heptane as a solvent and the efficiency of CRL-MWCNTs as a biocatalyst was compared with the free CRL, considering the incubation time, temperature, molar ratio of acid:alcohol, presence of desiccant as well as its reusability. It was found that the CRL-MWCNTs resulted in a 2-fold improvement in the percentage of conversion of geranyl propionate when compared with the free CRL, demonstrating the highest yield of geranyl propionate at 6h at 55°C, molar ratio acid: alcohol of 1:5 and with the presence of 1.0g desiccant. It was evident that the CRL-MWCNTs biocatalyst could be reused for up to 6 times before a 50% reduction in catalytic efficiency was observed. Hence, it appears that the facile physical adsorption of CRL onto F-MWCNTs has improved the activity and stability of CRL as well as served as an alternative method for the synthesis of geranyl propionate.

Research on Surface Roughness of Acid Etched Silicon Wafers

With the development of power electronic devices, the market demand for acid etched wafers of monocrystalline silicon, which has good surface properties and minimum surface roughness, increases rapidly. But there has been rarely report about the impact of acid etching process on the wafer surface roughness. This paper studied the surface roughness of the wafer, which was etched by mixture of HNO3, HF and HAC. The results showed that the surface roughness became smaller with the increase of wafer remove amount, while the roughness became worse with the service life extension of the acid; however, fluid infusion discharge method could be adopted in the etching process so that the etching acid system could achieve a relatively balanced state and wafer roughness became stabilized. The process mechanism was studied and analyzed in this investigation.

Supercritical Fluid Dissolution and Extraction of Trivalent Metal Cations from Different Matrices

Studies on the recovery of trivalent metal ions such as Nd3+Eu3+ (taken as homologs of Am(III)) from solid oxide (Nd2O3), Thorium concentrate (obtained from Monazite ore processing), tissue paper/surgical gloves (rubber), and plant samples have been carried out by supercritical fluid extraction (SFE) using supercritical CO2 and ethanol/nitric acid. N,N,N’,N’-tetraoctyl diglycolamide (TODGA) was used as the extractant in these studies. The results showed that the recovery of Nd increased with TODGA concentration from 50% (no TODGA) to 70% (10% TODGA) at 3 M HNO3 in ethanol. However, the extraction of Nd at 1 M HNO3 was invariant with 1-3% (v/v) TODGA concentration (73 ± 4%). Interestingly, REEs recovery from Th concentrate was ˜ 60% even without TODGA using ethanol/3 M HNO3 mixture. On the other hand, quantitative recovery of 152,154Eu from tissue paper and surgical gloves sample could be achieved using 3 M HNO3/ethanol mixture. This suggested that it would be possible to decontaminate the contaminated laboratory waste papers using SFE technique.

Modified disordered carbon prepared from 3,4,9,10-perylenetetracarboxylic dianhydride as an anode material for Li-ion batteries

To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon (DC) formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified via an acid treatment using a mixture of HNO3 and H2SO4. The modified disordered carbon (MDC) was characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) analysis, and scanning electron microscopy (SEM). FTIR spectra confirm the successful introduction of carbonyl groups onto the DC surface. Some pores appear in the columnar structure of MDC, as observed in SEM micrographs. Li+ ions intercalation/deintercalation is facilitated by the modified morphology. Electrochemical tests show that the MDC exhibits a significant improvement in discharge capacity and cycling stability. These results indicate that the MDC has strong potential for use as an anode material in Li-ion batteries.

Acid Decomposition of Yerba Mate (Ilex paraguariensis) Using a Reflux System for the Evaluation of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn Contents by Atomic Spectrometric Techniques

In the first part of this paper, two acid decomposition procedures for the determination of Al, Ca, Fe, Mg, Mn and Zn contents in yerba mate samples by inductively coupled plasma optical emission spectrometry (ICP OES) were compared. Using a reflux system, the samples were treated with a mixture of HNO3 and H2O2 for 3 hours at 220 °C in the digester block. The results from five commercial yerba mate samples were compared with the results obtained from microwave digestion. Good agreement between the procedures at a 95% confidence level was obtained with relative standard deviation (RSD) values lower than 10.0%. The accuracy was evaluated using addition and recovery experiments (80.5 to 112.8%). In the second part, Ca, Cd, Cr, Cu, Fe, K, Mg, Na, Pb and Zn concentrations were evaluated in the yerba mate infusion. The results showed that elements such as Na, K, Mg and Zn are easily transferred to the hot water used for the infusion. For Pb and Cd, the concentrations found in the analyzed samples were lower than the values established by Brazilian legislation.

Trace Metals Concentrations at the Atmosphere Particulate Matters in the Southeast Asian Mega City (Dhaka, Bangladesh)

Atmospheric particulate matters were collected on quartz fibre filters for 24 hours with a low volume sampler from January 2014 to March 2014 at the Southeast Asian mega city (Dhaka, Bang- ladesh). Particulate matters samples were analysed for eleven trace metals with inductively cou- pled plasma mass spectrometer (ICP-MS) at Ca Foscari University of Venice, Italy. Trace metals were extracted from filters with digestion method using a mixture of HNO3 and H2O2. The average concentration of the determined trace metals of As, Cd, Ni, Cu, Pb, Cr, Fe, Mn, Zn, Sband Se were 3.06, 6.28, 3.77, 11.98, 305.6, 9.2, 2057.0, 42.2, 303.3, 5.47 and 2.43 ng∙m −3 , respectively. Arsenic concentration is much lower in the atmosphere of Dhaka, though Bangladesh has severe arsenic problem in the ground water. Lead and cadmium concentrations showed decreasing trend in Dhaka compared than previous measurements—but still they have very high levels compared than Europe and USA. There is very limited information for Mn, Sb and Se concentrations in Dhaka air. Correlation studies showed that several trace metals had potential joint sources of origin, e.g., manganese is highly correlated with iron (r 2 = 0.97) and nickel (r 2 = 0.84), copper (r 2 = 0.86); lead with arsenic (r 2 = 0.79) and antimony (r 2 = 0.78). Enrichment factors analysis was also done with the data base for the respective metals in earth crust and coal fly ash. As and Cu both have com- bined sources, whereas Cd, Pb and Zn were from coal fly ash.Trace metals concentrations in Dhaka city air were much higher than Europe and USA but comparable or slightly lower than other south Asian countries. This is the first extensive study for the eleven trace metals with ICP-MS in Dhaka, * Corresponding author.

Determination of Some Selected Heavy Metals in Fish and Water Samples from Hawassa and Ziway Lakes

Samples of Tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) were collected from Hawassa and Ziway Lakes during March 1-20 of 2003 E.C. The moisture content of freeze-dried body of the fish collected from six sites ranged between 62.6% and 86.6% (m/m). An optimal procedure required 12 mL mixture of HNO3, HClO4, and H2O2 (3:2:1, respectively) to mineralize powdered samples in open refluxed digestion vessels: 0.5 g of the fish body. The concentrations of 3 toxic elements in the body of the fish determined by flame atomic absorption spectrophotometer varied, respectively, (mg of element/kg of fish); Cd = 0.4 - 1.85, Pb = 0.05 - 0.5 and Hg = 0.07 - 0.096. The concentration of those three heavy metals in water samples was also determined similarly by FAAS varied, respectively, as (mg of element/L of water sample); Cd = 0.06 - 0.66, Pb = 0.28 - 0.36 and Hg = 0.5 - 0.74. Application of the statistical t-test on heavy metal elements data has shown that there was a significant difference between the mean concentrations of Hg in water samples from the two Lakes. There is no significant difference between fish as well as water sample of the two lakes for the other metals.

Poly(4-vinylpyridine)-nitrating mixture complex (PVP-NM): solid nitrating mixture equivalent for safe and efficient aromatic nitration

PVP-NM prepared from poly(4-vinylpyridine) and nitrating mixture (1 : 1 mixture of HNO3 and H2SO4) is a safe and effective nitrating agent for both activated and deactivated arenes under mild conditions. The polymer can be retrieved and reused without losing the efficacy.

Sequential separation of ultra-trace U, Th, Pb, and lanthanides using a simple automatic system.

Uranium, thorium, lead, and the lanthanides were automatically and sequentially separated with a single anion-exchange column. This separation was achieved using eluents consisting of a simple and highly pure acid mixture of HCl, HNO3, acetic acid, and HF. The elements of interest were separated from the major constituents, which included alkaline metal elements, alkaline earth metal elements, and iron. This simple and automatic system is driven with pressurized nitrogen gas and controlled using a computer program. An optimized separation was accomplished under the following conditions: a 50 mm long and 2 mm diameter column, 11 μm diameter anion-exchange resin, and a 35 μL min(-1) flow rate. Using this system, 50 ng of varied elements in a 100 μL feed solution were perfectly separated within 5 h with >400 decontamination factors and >95% yield. In order to evaluate the performance of this system, a reference powdered rock sample was separated using this system. Abundances of objective elements, including 0.23 ng of lutetium, were accurately determined without corrections of chemical recovery yield or subtraction of the process blank. This separation technique saves time and effort for chemical processing, and is useful for ultra-trace quantitative and isotopic analyses of elements in small environmental samples.

Effect of acid treatment on the multiwalled carbon nanotubes

Carbon nanotubes (CNT) have gained great interest for research in many applications because of their unique characteristics, such as having high porosity, high surface area and the ability to be functionalised by a wide spectrum of surface functional groups. However, owing to the hydrophobic nature, CNT could not be dispersed uniformly in the solution, thus restricting the applications of CNT in industry. In order to resolve this problem, multiwalled carbon nanotubes (MWCNT) were treated with nitric acid (HNO3), and the mixture of HNO3 and sulphuric acid (H2SO4). Different reagents for acid treatment seem to affect the bundling arrangement of nanotubes, the attachment of functional groups and the degree of functionalisation. The treated MWCNT resulted in lesser agglomeration of nanotubes, reduced the impurities, and give more attachment of functional groups. The treated MWCNT samples that have more functional groups can be considered as a potential material for applications.