Aqueous Nitrate Solutions Research Articles

Investigation of the deposition of calcium fluoride nanoparticles on the chips of CaF2 single crystals

The deposition of calcium fluoride nanoparticles on single crystal chips of calcium fluoride was studied. CaF2 nanoparticles were synthesized by co-precipitation from aqueous nitrate solutions using hydrofluoric acid as a fluorinating agent at a batch system. The prepared samples were examined by atomic force microscopy, scanning electron microscopy, transmission electron microscopy and optical transmission. There is an inhomogeneous coating of the substrate surface with submicron particles of about 100–150 nm in size, which are clusters of nanoparticles of 15-20 nm in size. The initial nanoparticles coherently grow on the surface of the crystal substrate. Heat treatment of the substrate-deposited layer composite at 600 °C leads to the coalescence of submicron particles and the formation of a porous layer of a complex structure.

Decoration of Ag Nanoparticle on ZnO Nanowire by Intense Pulsed Light and Enhanced UV Photodetector

Zinc oxide (ZnO) nanowires (NWs) are wide-bandgap semiconductors that absorb ultraviolet (UV) radiation. Various post-treatment processes have been studied to improve the optical properties of the as-grown ZnO NWs. Among them, Ag nanoparticles (NPs) effectively improved the optical properties on the surface of the ZnO NWs. In this study, ZnO NWs were synthesized via the hydrothermal synthesis method. ZnO NWs were decorated with Ag NPs on the surface of the ZnO NWs in a silver nitrate (AgNO3) aqueous solution by intense pulsed light (IPL) irradiation. Ag NPs were successfully decorated under the following conditions: aqueous AgNO3 solution of 100 nM, an energy of 1 J/cm2, and an exposure time of 8 ms. The responsivity and sensitivity of the ZnO NW UV photodetectors increased by 7.43 and 3.37 times, respectively. The IPL process makes it possible to decorate Ag NPs in a simple manner within an extremely short time.

Fertilization and soil pH affect seed and biomass yield, plant morphology, and cadmium uptake in hemp (Cannabis sativa L.)

The phytoremediation potential of industrial hemp (Cannabis sativa L.) becomes a new target of hemp cultivation. The ability to accumulate cadmium depends on genetic, anatomical and physiological characteristics of the varieties. The published data show that the level of fertilization affects many metabolic pathways, the development of plants and cannabinoid concentration. In addition, there are inconsistent data on the cadmium accumulation capacity depending on the mineral nutrition and pH. A study was carried out to assess the potential of two hemp varieties (‘Henola’ and ‘Białobrzeskie’) as a decontaminator of cadmium, depending on soil pH and phosphorous fertilizer level. The influence of pH, fertilization and cadmium concentration in the soil on plant morphology and on the yield of seeds and biomass were also assessed. The soil with two different pH was used in the experiment: acidic (pH 4) and alkaline (pH 7.5). Two concentrations of aqueous solution of cadmium nitrate (Cd(NO3)2) were added to the soil to obtain final concentration of Cd: 4 mg/kg and 8 mg/kg of soil, respectively. The phosphorous fertilizer was supplied in the amounts of: 50 kg/ha, 100 kg/ha, 150 kg/ha. The cadmium content in soil and in hemp plants was determined with a flame atomic absorption spectrophotometry and a plasma optical emission spectrometry (ICP-OES), respectively. Based on two years of experiments, the highest cadmium concentration in seeds and biomass, were revealed for Henola variety, when fertilizer was applied in the amount of 150 kg/ha. The results revealed that the fertilization ant pH level are important factors in the cultivation of hemp. They affect the intensity of cadmium uptake from the soil. Higher soil pH was correlated with the highest concentration of Cd in seeds and straw of Białobrzeskie variety. Such a relationship has not been demonstrated in the case of the Henola variety. The highest BCF (bioconcentration factor) value was calculated for Cd uptake in ‘Henola’ biomass. Increased cadmium concentration in the soil did not adversely affect development and growth of two hemp varieties studied. The phytoremediation potential of individual hemp varieties is different. Higher pH increases the cadmium uptake by some hemp varieties, but in the case of other varieties this relationship is reversed. It is necessary to assess the phytoremediation potential of each hemp cultivar in different agrotechnical conditions.

Pitfalls in Electrochemical Liquid Cell Transmission Electron Microscopy for Dendrite Observation

The growth of dendrites on the electrodes during charge–discharge cycles can lead to short‐circuit and potential ignition, which limit the capacity and application of the rechargeable batteries. With the development of in situ electrochemical liquid cell transmission electron microscopy, the growth process of metallic dendrites can be observed in real‐time. However, there remains a great challenge to operate the electrochemical liquid cell experiments successfully and repetitively. Herein, the lithium‐ion battery electrolyte system and the other electrolyte system of silver nitrate with sodium nitrate aqueous solution are adopted in our experiments to demonstrate the problems in conducting electrochemical liquid cell experiments. Influence factors are summarized, including the tube residual, cleanliness of electrodes, bubbles in the liquid cell, and the stability of the electrochemical system. All these aspects affect the electrochemical liquid cell experiments, and understanding these influencing factors is beneficial to improve the success rate of experiments. This work may offer guidance for the wide application of in situ electrochemical liquid cell transmission electron microscopy in observing the growth of dendrites in batteries.

Biogenic Synthesis of Silver Nanoparticles using Aspergillus Aureoles (Endophyte) and Demonstration of their Anti- microbial Activity

The nanoparticles have been recognized to play vital coating roles in electronics, energy contact actions, biology, and medicine due to their unique properties for two decades. In the present study, silver nanoparticles were synthesized using an endophytic fungus, Aspergillus aureoles, and subjected to antimicrobial activity. The treatment of an aqueous solution of silver nitrate (3 mM) with cell-free filtrate of Aspergillus aureoles resulted in the production of stable and crystalline silver nanoparticles. Silver nanoparticles were characterized using different studies, such as Ultraviolet-Visible Spectroscopy, High-Resolution Transmission Electron Microscopy, X-ray Diffraction Spectroscopy, Fourier Transform Infrared Spectroscopy, and Dynamic Light Scattering. The antimicrobial activity was carried out by the well diffusion method. The nanoparticles were in a spherical shape with an average particle size of 12-15 nm as observed in a High-Resolution Transmission Electron Microscope. The crystalline nature and size of nanoparticles were confirmed by the X-ray Diffraction Spectroscopy and Selected Area Electron Diffraction, respectively. The Fourier Transform Infrared Spectroscopic study revealed the involvement of various functional groups of Aspergillus aureoles extract in stabilizing the nanoparticles. These nanoparticles exhibited potent antimicrobial activity against both gram-positive and negative bacteria, which was comparable to the standard antibiotic. Thus, the study established the possible use of green silver nanoparticles in controlling microbial infections and developing a novel broad-spectrum antimicrobial agent/s.

Nitrous Acid (HONO) Formation from the Irradiation of Aqueous Nitrate Solutions in the Presence of Marine Chromophoric Dissolved Organic Matter: Comparison to Other Organic Photosensitizers

Nitrous Acid (HONO) Formation from the Irradiation of Aqueous Nitrate Solutions in the Presence of Marine Chromophoric Dissolved Organic Matter: Comparison to Other Organic Photosensitizers

Plasma-solution synthesis of particles containing transition metals

The paper proposes a new method for the synthesis of powders containing transition metals using a plasma-solution system. The reactor was an H-shaped glass cell, the two parts of which were separated by a cellophane membrane. A discharge consisting of two discharges - with a liquid cathode and a liquid anode - a high voltage is applied to titanium electrodes located above the surface of the solution. Aqueous solutions of zinc, iron, cadmium, cobalt, nickel, and copper nitrates were used as the liquid phase. Under the action of the discharge on the liquid anode, in the region of contact of the discharge with the solution the formation of a colloidal suspension was observed. The kinetics of the process of synthesis of solid-phase particles in solution under the action of a discharge have been studied. The chemical composition and morphology of the formed solid phase have been established. The mechanisms of chemical reactions occurring in the solution under the action of plasma, and the mechanisms of formation of transition metal oxides in the process of calcining the synthesized powders have been proposed.

Photodegradation of an Anilide Fungicide Inpyrfluxam in Water and Nitrate Aqueous Solution.

The photodegradation behavior of a new anilide fungicide, inpyrfluxam [3-difluoromethyl-N-[(R)-2,3-dihydro-1,1,3-trimethyl-1H-inden-4-yl]-1-methylpyrazole-4-carboxamide] (1), was investigated in aqueous buffer and nitrate solutions under irradiation with artificial sunlight (λ > 290 nm). In both media, 1 mainly photodegraded via oxidation at the 3'-position of the Indane ring, cleavage of the C-N bond of the amide linkage and N-phenyl ring bond, and finally mineralization to carbon dioxide. No isomerization of 1 occurred at the 3'-position of the Indane ring. In the presence of nitrate ion, which originates from fertilizer in agricultural fields, the degradation of 1 was significantly accelerated as compared with buffer solution, and the reaction rate was strongly correlated with the concentration of hydroxyl radicals derived from the photolysis of nitrate ions. The reaction rate constant of hydroxyl radicals with 1 was determined to be 3.0 × 1010 /M/s, which was higher than that of hydroxyl radicals with other pesticides possessing aromatic rings.

Total oxidation of carbon monoxide, VOC and reduction of NO2 with catalytic ceramic filter media

This paper deals with the effect of catalyst loading on the activity and selectivity of CuOx−MnOy catalysts on alumina-silicate supports (fiber material-Al2O3(44)/SiO2(56)). A special focus lies on the oxidation of CO, on mixtures of VOC from 1-butene, isobutane, n-butane, propane, ethene, and ethane, as well as on CO oxidation in the presence of NO2. The catalysts are prepared through wet impregnation of the filter section with an aqueous solution of copper and manganese nitrate. The rate of CO oxidation for small carbon monoxide concentrations of up to 1 vol.% is independent of catalyst loading in the filter material. In contrast, at a carbon monoxide concentration of around 3 vol.%, it is found that the rate of CO oxidation increased rapidly with increasing catalyst loading of the filter material. The highest catalytic activity of over 93% CO elimination is achieved at 290 °C for 1 vol.% CO and smaller catalyst loading and for 3 vol.% CO with higher catalyst loading. In long-term stability tests, complete CO conversion is measured without deactivating the catalyst at 390 °C for at least 100 h. The highest catalytic activity for VOC elimination of 90% is achieved in the temperature range of 350–420 °C. During the CONO2 reaction with and without O2, a constant decrease in the CO oxidation rate is observed, while the NO2 reduction rate remained constant at a temperature below 300 °C.

Study of the Effect of Nitrate and Sulfate Solutions on the Properties of Copper Nanopowder Synthesized by Electrochemical Method

The electrochemical method is efficient, cost effective, and environmentally friendly process. Copper nanopowder has been known, as a nontoxic, inexpensive, highly conductive, excellent microbial agent, catalytic, and sensors applicable. Copper nanopowder was prepared by an electrochemical method under various conditions. The effect of type and concentration of electrolyte solution, and the sample treated with thiourea and ascorbic acid on the size and purity of copper nanopowder was investigated. Two different salts copper: sulfate and nitrate aqueous solutions (CuSO4.5H2O), Cu(NO3)2.5H2O were used to produce copper nanopowder. The synthesized copper nanopowder was identified using X-ray diffraction (XRD), the scanning electron microscope (SEM), and Energy Dispersive Spectrum (EDS). The results of XRD patterns revealed a high degree of crystallinity, monophasic nature, and pure copper powder with no impurities or oxides observed for both electrolyte solutions after treated with 2 percent of ascorbic acid. It was confirmed that particle size at room temperature was as small as 25nm when the copper nitrate is used as an electrolyte solution compared to copper sulfate (41nm).

Immobilization of Silver Nanoparticles on the Surface of Cellulose Nanofibers Using High-Pressure Wet-Type Jet Mill

Composite material immobilized silver nanoparticles (NPs) on the surface of cellulose nanofibers (CNF) was prepared using a high-pressure wet-type jet mill. A mixture both containing an aqueous silver nitrate solution and a CNF suspension was prepared as a raw starting material. The mixture was pulverized with the high-pressure wet-type jet mill at a pressure of 100 or 200 MPa. An X-ray diffraction pattern of the obtained sample revealed the presence of not only cellulose type I crystallites but also silver metal crystallites. According to observation by field-emission scanning electron microscopy, it was found that many silver NPs were immobilized on the surface of CNF. Note that almost all the silver NPs were well dispersed on the surface of CNF. It was cleared that the silver NPs had a spherical in shape with an average particle size of about 3 nm by the transmission electron microscope observation. The average size of the silver NPs slightly increased with the number of jet milling cycles, however, the change in the discharge pressure of the high-pressure wet-type jet mill did not affect the NPs size. The silver content in the composite materials increased with increasing both the number of jet milling cycles and the discharge pressure. The silver NPs were deposited by using the thermal energy released in the jet milling process, and their grain growth was then inhibited because the suspension was cooled immediately through the cooling tube. Therefore, it was assumed that silver NPs with a narrow size distribution could be immobilized on the surface of CNF.

Crystal structures with infinite chains based on antimony tartrate dimers

Abstract Seven complex metal antimony tartrates have been synthesized in single crystal form by slowly evaporating aqueous solutions of potassium antimony tartrate (tartar emetic) and divalent metal nitrates or perchlorates. Crystal structures of these compounds all contain infinite chains formed by linking antimony tartrate dimers with divalent metal ions. While infinite chains of antimony tartrate dimers bridged by single Zn2+ ions or by double Mg2+ ions were reported previously, new types of chains with alternating single and double bridging cations are observed in this work.

Direct Observation of Induced Graphene and SiC Strengthening in Al–Ni Alloy via the Hot Pressing Technique

In this study, Al/5 Ni/0.2 GNPs/x SiC (x = 5, 10, 15, and 20 wt%) nanocomposites were constituted using the powder metallurgy–hot pressing technique. The SiC particles and GNPs were coated with 3 wt% Ag using the electroless deposition technique then mixed with an Al matrix and 5% Ni using ball milling. The investigated powders were hot-pressed at 550 °C and 600 °C and 800 Mpa. The produced samples were evaluated by studying their densification, microstructure, phase, chemical composition, hardness, compressive strength, wear resistance, and thermal expansion. A new intermetallic compound formed between Al and Ni, which is aluminum nickel (Al3Ni). Graphene reacted with the Ni and formed the nickel carbide Ni3C. Additionally, it reacted with the SiC and formed the nickel–silicon composite Ni31Si12 at different percentages. A proper distribution for Ni, GNs, and SiC particles and excellent adhesion were observed. No grain boundaries between the Al matrix particles were discovered. Slight increases in the density values and quite high convergence were revealed. The addition of 0.2 wt% GNs to Al-5Ni increased the hardness value by 47.38% and, by adding SiC-Ag to the Al-5Ni-0.2GNs, the hardness increased gradually. The 20 wt% sample recorded 121.6 HV with a 56.29% increment. The 15 wt% SiC sample recorded the highest compressive strength, and the 20 wt% SiC sample recorded the lowest thermal expansion at the different temperatures. The five Al-Ni-Gr-SiC samples were tested as an electrode for electro-analysis processes. A zinc oxide thin film was successfully prepared by electrodeposition onto samples using a zinc nitrate aqueous solution at 25 °C. The electrodeposition was performed using the linear sweep voltammetric and potentiostatic technique. The effect of the substrate type on the deposition current was fully studied. Additionally, the ohmic resistance polarization values were recorded for the tested samples in a zinc nitrate medium. The results show that the sample containing the Al-5 Ni-0.2 GNs-10% SiC composite is the most acceptable sample for these purposes.

A Novel Tetranuclear Silver Compound with bis(3,5-dimethylpyrazol-1-yl)acetate: a Simple Synthesis Yielding Complex Crystal Structure

A novel tetranuclear silver coordination compound with the formula [Ag4(bdmpza)4]×10H2O (bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate) was synthesized by a reaction between an aqueous solution of silver nitrate and an aqueous solution prepared by bis(3,5-dimethylpyrazol-1-yl)acetic acid and potassium hydroxide (1:1 molar ratio). The obtained compound was characterized by elemental analysis, coupled thermogravimetric-mass spectrometry analysis, vibrational IR spectroscopy, and its crystal structure was determined by single-crystal X-ray diffraction method. Furthermore, the obtained crystal structure was additionally evaluated by Hirshfeld surface analysis.

Radical-Doped Crystalline Lanthanide-Based Photochromic Complexes: Self-Assembly Driven by Multiple Interactions and Photoswitchable Luminescence.

Stimuli-responsive functional materials, especially the light stimulation color change and tunable fluorescent materials, have received considerable attention because of their broad applications in smart materials. Herein, a series of lanthanide-based [Ln = Nd(III) (1), Sm(III) (2), Eu(III) (3), Gd(III) (4), Tb(III) (5), Yb(III) (6), and Lu(III) (7)] crystalline complexes were attained by simply adding the aqueous lanthanide nitrate solution to the water-soluble naphthalenediimide derivative. The obtained lanthanide-based crystalline materials not only show significant photochromism but also possess reactive organic radicals under ambient conditions. Intriguingly, photoswitchable near-infrared (NIR) fluorescence was realized in the crystalline complex 1. The structures of these crystalline materials were systematically studied to clarify the weak interaction-assisted charge-transfer process. The underlying multiple-interaction-assisted supramolecular self-assembly, the radical-doped nature, and the corresponding photochromic mechanism were thoroughly unearthed by single-crystal X-ray diffraction, in situ solid-state UV-vis diffuse reflectance, and electron paramagnetic resonance spectrometric analysis.

Synthesis of CuAl2O4 Nanoparticle and Its Conversion to CuO Nanorods

The molten salt approach was used to convert CuAl2O4 nanoparticles to CuO nanorods in this study. Molten hydroxide (NaOH) synthesis was chosen over molten salts (NaCl/KCl) for removing aluminium oxide from copper aluminate at low temperatures. The molten salt process is environmentally beneficial. Polymeric precursors were used to make nanosized copper aluminates. Alginic acid polymer is used to gel aqueous solutions of copper acetate and aluminium nitrate, yielding precursor after further heating. The precursor provides 14 nm nanosized copper aluminates after being heated at 900°C for 5 hours. XRD, FTIR, SEM, and TEM were used to characterize the nanosized copper aluminate powder. Solid state mixing and solution technique were used to investigate molten hydroxide treatment of spinel CuAl2O4. The products of the reaction were identified using XRD. FTIR and SEM are also used to analyze the sample. Using UV-DRS absorbance spectrum analysis, the optical characteristics of CuAl2O4 and CuO nanorods were examined. Using the Tauc plot method, the band gaps of CuAl2O4 and CuO were calculated to be 4.3 and 3.93 eV.

Acid-basic properties of chromium(III) oxide surface

The article is devoted to the study of the nature and number of acid-base centers on the surface of chromium(III) oxide obtained by precipitation from an aqueous nitrate solution. The curve of the distribution of the number of acidbase centers of the samples is plotted depending on the indicator of the ionization constant of indicators. It was determined that the main Lewis centers make the main contribution to the acidity of the samples; there are also Bronsted centers of different acidity. A comparative analysis of the structural features of the surface of oxides of chromium, zinc and binary systems Cr (III)–Zn (II) was carried out according to the results of X-ray phase analysis of oxides and thermolysis of the corresponding hydroxides. Based on this, the possibility of obtaining nanosized catalysts based on oxide-hydroxide systems of chromium with a number of 3d-metals obtained in the process of polynuclear hydroxocomplexation is predicted.

Green Synthesis, Antioxidant and Antimicrobial Activity of Silver Nanoparticles Using Gnetum africanum Extracts

The synthesis and application of nanoparticles is an important area of research that is gaining attention recently. In this recent project, we report the synthesis of silver nanoparticles, AgNP using aqueous solution of silver nitrate and Gnetum africanum leaf extract (reducing agent). The synthesis of AgNP was achieved by mixing aqueous solution of silver nitrate (70ml, 15.75mM) with a solution of Gnetum africanum leaf extract 100 ml) in a reaction flask and allowed to stand for 24 hours in a dark cupboard. A color change from light brown to yellowish brown was observed which indicated that synthesis of silver nanoparticles took place. The presence of AgNP was ascertained using UV-vis spectra analysis and absorption at 442 nm showed the presence of AgNP. The antioxidant assay of both the synthesized AgNP and the leaf extract was determined using DPPH. Antimicrobial activity was conducted using three different organisms which were Staphylococcus aureus, Escherichia coli and Pseudomonas respectively. The antioxidant results using DPPH scavenging ability of AgNp showed that at concentrations of 2mg/ml,1mg/ml and 0.1mg/ml, the percentage inhibition of DPPH by AgNp was 61.69, 53.06 and 38.31 respectively and that of Gnetum africanum leaf extract was 81.32, 78.49, and 58.29 respectively at the same concentrations using Ascorbic acid as a standard. The antimicrobial activity of both the synthesized AgNps and Gnetum Africanum Leaf extract using one gram positive bacteria (Staphylococcus aureus) and two gram negative bacteria (Escherichia coli and Pseudomonas) revealed that the synthesized AgNps showed lesser activity than Gnetumafricanum leaf extract for both the gram positive bacteria (Staphylococcus aureus) and gram negative bacteria (Pseudomonas) and (Escherichia coli). From the above findings, it can be observed that Gnetum Africanum Leaf extract reduced Ag+ to Ag0 and also both the synthesized AgNps and the Gnetum Africanum Leaf extract showed reasonable antioxidant activity against DPPH and antimicrobial activity against the tested microorganisms. This implied that both samples have medicinal values.

On altering the wetting behaviour and corrosion resistance of a large metallic surface area by wire electrochemical texturing

This paper presents a novel and practically applicable method for a quick fabrication of uniform surface patterns (periodic micro-pillars with rectangular and square cross-section) on a large surface area of any conducting or semi-conducting material using Wire Electrochemical Micromachining (Wire-ECMM). Micro pillars with a rectangular cross-section are generated by machining mutually perpendicular micro channels. The depth, spacing, and cross-sectional area of pillars are controlled by varying the process parameters and tool travel distance. Primary pillars (level-1 texture) are machined with a constant Direct Current (DC) voltage and secondary pillars (level-2 texture) are machined with a pulsed DC voltage using a tungsten wire of diameter 100 μm. An aqueous solution of sodium nitrate (NaNO 3 ) is selected as an electrolyte having a pH of about 7.01. A good repeatability in the geometrical parameters of a pillar profile is observed on analysing 3D profilometer micrographs of the textured surfaces. Wetting behaviour of textured surfaces with different geometrical parameters is observed using drop shape analyser. A surface with two levels of textures offers highest contact angle of 147.3° with deionized water. Corrosion current and resistance of the textured surfaces are obtained using Linear Sweep Voltammetry (LSV) and Electrochemical Impedance Spectroscopy (EIS), respectively. Results suggest that corrosion resistance depends upon the area of texture and is highest for the sample with the largest textured area. Also, a sample with the smallest value of area factor (ratio of total area of the top surface of all the pillars in a region to the total projected area of a region) offers highest resistance to corrosion. • A novel approach for large area texturing on any conducting and semi-conducting surface using Wire Electrochemical Micromachining (Wire-ECMM). • A study of the influence of different process parameters on various geometrical features of a textured surface. • A detailed characterization of different textured surfaces using SEM imaging and surface topography. • In depth analysis of the wetting and corrosion behaviour of the textured surfaces using drop shape analyser and Electrochemical Impedance Spectroscopy (EIS).

Synthesis and Characterization of Lead Dibutyl Dithiophosphate Nanoparticles

We examined the interaction of aqueous solutions of lead nitrate and sodium dibutyl dithiophosphate and showed the formation nanoparticles of lead dibutyl dithiophosphate. The effect of reaction parameters on the synthesis of nanoparticles was studied and the optimal conditions for the formation of their stable hydrosols were determined. The obtained products were investigated by methods of optical spectroscopy, dynamic light scattering. The average size of 15–20 nm, but due to the low surface charge, they are combined into larger aggregates. The UV‑vis spectra has absorption maximum at about 320 nm. TEM micrographs and Pb 2p, S2p XAS spectra revealed a composition and structure of the particles. These nanoparticles can play an important role in the flotation of sulfide minerals of nonferrous metals