Nitric Acid Solution Research Articles

Nutrient Content of Lettuce Plants in a Hydroponic System with the Addition of Acid Solution

Hydroponics is a plant cultivation technique that uses water as a growing medium. The acidity level (pH) of water is an important factor in the success of hydroponic plant cultivation. High water acidity (pH>8) can be controlled by adding acid solution to a pH level of 5.8-7.0. This research was conducted to examine the nutrient content of lettuce. The research used a Randomized Block Design with 9 treatments (3 types of water and 3 types of acid solution). The types of water used include Kebonsari well water, Bugul Kidul well water and Pasuruan city PDAM water. The acid solutions used include nitric acid, phosphoric acid and sulfuric acid. The results of the research show that adding acid solutions to all types of water produces different plant nutrient contents. The addition of nitric acid and phosphoric acid solutions respectively had a significant effect on the N and P nutrient content of lettuce plants. The addition of phosphate solution can be recommended as a pH lowering solution in hydroponic cultivation.

Extraction of Actinides and Lanthanides from Nitric Acid Solutions with Phosphorylated Pyrazines

Extraction of Actinides and Lanthanides from Nitric Acid Solutions with Phosphorylated Pyrazines

Extraction of Platinum from Low-Concentration Refining Nitric Acid Solutions Using Electrolytic and Sulfide Precipitation

Extraction of Platinum from Low-Concentration Refining Nitric Acid Solutions Using Electrolytic and Sulfide Precipitation

TRAITEMENT DU PHOSPHATE NATUREL DE LA TAPOA (NIGER) PAR DES ACIDESMINERAUX ET ORGANIQUES

This study propose away for the development of hardly soluble natural phosphate. Thusitwascarried out, the dissolution of natural phosphate from Tapoa (Niger) in solutions of mineralacids (nitricacid and sulfuricacid) and in solutions of organicacids (citricacid and ethylene diamine tetraacetic EDTA) in function of pH and attack time. The resultsobtainedshowedthat the maximum rate of dissolvedphosphorus as a percentage of phosphoric anhydride (P2O5) is 14.08% and 15.99% respectively in solutions of nitricacid and sulfuricacid at the concentration of after 7 hours of attack. In organicacid solutions, the dissolution rate is 4.67% and 5.17% respectively in citricacid and EDTA solutions at the same concentration. In addition, the dissolution rate decreaseswhen the acid concentration decreaseswhileit tends to increasewith the attack duration regardless of the acid solution used (mineral or organic). Also, this dissolution rate isalmostzero in solutions of organicacidswhen the concentrationis.

Evaluation of performance of advanced refractory materials intended for the arch of the electric furnace for HLW vitrification

The paper presents the results of the studies of refractory materials produced by the company Keralit, JSC Borovichi Refractories Plant and STC Bakor and intended for the arch of the electric furnace EP-6 for HLW vitrification. The studies have determined strength properties and acid resistance of the materials when exposed to vapors of nitric acid and nitric acid solution. It has been concluded as a result of the studies that optimum materials for construction of the furnace arch are MKRTU-50 and MKV-65 materials produced by JSC Borovichi Refractories Plant and STC Bakor, respectively.

A comparison of various XAD-Amberlite resins impregnated with dicyclohexyl-18-crown-6 for strontium removal

In the present study, four different varieties of Amberlite resin impregnated with dicyclohexyl-18-crown-6 were employed as an adsorbent for the selective extraction of strontium ions (Sr2+) from nitric acid solutions and dicyclohexyl-18-crown-6 impregnated in XAD-4 resin shows highest adsorption of Sr2+ from nitric acid solution. The effect of important parameters such as concentration of nitric acidic in the medium, adsorbent dosage, contact time, initial Sr (II) concentration and temperature were investigated in a batch system. The results demonstrated that the adsorption rate is high in the first 30 min and equilibrium was achieved after 300 min at 3 mol/L nitric acid medium. The results of the kinetic evaluations fit excellently with the pseudo-second-order model with a correlation coefficient R2 = 0.998. The prepared adsorbent extracts Sr (II) by following the Langmuir isotherm with a maximum adsorption capacity of 9.17 mg/g. Thermodynamic investigations indicated that the Sr (II) adsorption is an exothermic and spontaneous process. Strontium ions desorbed from resin in an acceptable percentage (98.9%) with double distilled water. In addition, the adsorption capability of the adsorbent in real water samples and also the effect of the existence of coexisting ions on the extraction of Sr (II) were assessed.

Synthesis, Structure, and Energetic Characteristics of Perovskite Photocatalyst SrTiO3: an Experimental and DFT Study

SrTiO3-based photocatalysts have become widely used due to their excellent properties such as high thermal stability, photocorrosion resistance, and stable structure that can be modified by doping and making composites. In this work, SrTiO3 powder was prepared from Sr(NO3)2 and TiO2 precursors by a simple chemical precipitation method followed by calcination. It was determined that calcination at 900 °C followed by treatment in nitric acid solution produced cubic SrTiO3 particles without the presence of any impurities. In addition, structural, morphology, and energetic characterization using experimental and theoretical aspects are presented. Within the framework of density functional theory, the electronic properties of SrTiO3 have been investigated in the Quantum ESPRESSO software package using the PBE functional under the generalized gradient approximation (GGA). The band structure and density of states were obtained, and the width of the bandgap was determined.

An isotope generator of Po-210 based on SR resin

The work describes an isotope generator of polonium-210 based on an extraction chromatographic resin SR Resin. It was shown that a high selectivity of 4,4’(5’)-di-t-butylcyclohexano-18-crown-6, an active component of SR Resin, for lead allows a clear separation of Pb-210 from impurities, easy elution of Po-210 with 5–7 mL of 0.05 M nitric acid solution as well as good retention of Pb-210 in the generator. The content of alpha emitting impurities in the Po-210 eluate did not exceed 0.65%. The experience of 3-years exploitation of the generator is described. It was shown that the SR Resin was stable against irradiation and complete drying, and Pb-210 loss from the SR Resin column for 3 years (seven elutions) was near to loss due to its radioactive decay within the error limits (less than 7%).

Recovery of Rhodium, Ruthenium, and Palladium from Nitric and Hydrochloric Acid Solutions with Iron(III) Hexacyanoferrate(II)

Recovery of Rhodium, Ruthenium, and Palladium from Nitric and Hydrochloric Acid Solutions with Iron(III) Hexacyanoferrate(II)

The electrochemical study of the garlic extract as a corrosion inhibitor for brass in the nitric acid solution

The aim of this study was to investigate the corrosion behavior of the brass alloy in the 1 M HNO3 solution with the different concentrations of the green inhibitor (Garlic extract). In the first step, the fourier transform infrared spectroscopy was used to identify the chemical composition of the inhibitor. The inhibition effect of the garlic extract on the corrosion behavior of the brass alloy was investigated by the polarization and electrochemical impedance spectroscopy test. The results of the polarization test showed that the garlic extract in the acidic environment acted as a mixed-type inhibitor, and with increasing the inhibitor concentration, the inhibitor efficiency increased from 60 % to 93.74 %. In addition, the results of the electrochemical impedance test revealed that by increasing the inhibitor concentration, the capacitance of the capacitor of electric double layer decreased, while the solution resistance increased. In follow, the effect of temperature on the corrosion behavior of the brass alloy with the presence of the garlic extract in the acidic solution was investigated using the electrochemical techniques as well. The results showed that by increasing the temperature, the inhibitor efficiency decreased from 93.74 % to 83.47 % at 3 g/L of inhibitor. Furthermore, the surface of the sample after dipping in the nitric acid solution containing garlic extract was examined using a scanning electron microscopy and an atomic force microscopy. The adsorption of the inhibitor molecules on the surface of the brass alloy at all temperatures was studied using the Langmuir adsorption isotherm and then both chemical and physical mechanisms were observed due to the adsorption of the garlic extract on the surface of the brass alloy in the 1 M HNO3 solution.

Chemically-stable flexible transparent electrode: gold-electrodeposited on embedded silver nanowires

Silver nanowires (AgNWs) with a low diameter, high aspect ratio, stable suspension, and easy synthesis have recently attracted the optoelectronic industry as a low-cost alternative to indium tin oxide transparent conductive films. However, silver nanowires are not chemically stable, and their conductivity diminishes over time due to reactions with atmospheric components. This is a bottleneck for their wide industrial applications. In this study, we aim to address this issue by synthesizing silver nanowires with an average diameter of approximately 65 nm and a length of approximately 13 µm. The prepared Ag nanowires are then applied to fabricate transparent, flexible, and chemically stable conductive films. The fabrication includes spraying of silver nanowires suspension on a glass substrate followed by Dr. blade coating of polystyrene (PS) solution and delamination of the PS-AgNWs film. The resulting film exhibits an optimum sheet resistance of 24 Ω/□ and transmittance of 84%. To further enhance the stability of the transparent conductive film, the facial and scalable double pulse electrodeposition method is used for coating of gold on the exposed surface of the AgNWs embedded in PS. The final transparent film with gold coating demonstrates a remarkable stability under harsh conditions including long exposure to UV light and nitric acid solution. After 100 min of UV/Ozone treatment, the increase in sheet resistance of the optimal PS-AgNW@Au sample is 15.6 times lower than the samples without gold coating. In addition, the change in sheet resistance after 2000 bending cycles in the optimal PS-AgNW@Au electrode is measured and it showed an increase of only 22% of its initial sheet resistance indicating its good flexibility. The proposed electrode performs an excellent chemical stability, good conductivity, transparency, and flexibility that makes it a potential candidate for various optoelectronic devices.

TECHNOLOGICAL BASIS OF THE PROCESS OF ZIRCONIUM AND HAFNIUM SEPARATION

The paper presents the results of industrial testing of the process and equipment for the extraction separation of zirconium and hafnium in a single technological cycle with the production of high-purity nitrate compounds and pure nitric acid solutions as raw materials for the production of sodium nitrate. It is shown that the efficiency of the extraction process is determined primarily by the purity of the nitric acid solution by the content of a critical impurity – silicic acid, which causes an undesirable emulsification process and disrupts the stability of the process. Optimal conditions have been determined under which the formation of non-extractable forms of zirconium and hafnium is excluded. The replacement of pulsating columns with centrifugal extractors reduced operating costs by reducing the volume of a one-time load of a flammable extractant and its losses as a result of hydrolysis. This increased the degree of separation of zirconium and hafnium. Centrifugal extractors provided high process kinetics, reduced production areas, and increased labor productivity and product quality.

Extraction of Actinides and Lanthanides from Nitric Acid Solutions with Diphosphine Dioxides in the Presence of an Ionic Liquid

Extraction of Actinides and Lanthanides from Nitric Acid Solutions with Diphosphine Dioxides in the Presence of an Ionic Liquid

ENHANCEMENT OF BIOGAS GENERATION BY UTILIZING RAW AND MODIFIED WITH HNO3 BIOCHAR OBTAINED FROM PYROLYSIS OF BIOMASS AND DIGESTATE

Biomass- and digestate-derived biochars were modified with nitric acid solution and examined in biochemical methane potential (BMP) tests to determine the effect of pretreatment on each of the different materials capability to improve the biogas production from the anaerobic digestion of conventional substrates such as corn silage. Methane yields from corn silage (0.308 m3kgVS-1) were over the average value for the specific type of lignocellulosic material. Addition of digestate-derived biochar (BCD) in AD process improved the methane production 1.13-fold. However, the sawdust-derived biochar (BCS) resulted in an even greater methane release of 0.374 m3kgVS-1. Chemical treatment reduced the pH of BCs from 10.29 and 11.54 to 3.10 and 2.81 for BCS and BCD, respectively while had a significant impact on materials composition almost removing the ash and metal elements from BCS and markedly decreasing 1.43-fold the ash fraction and by 70-75 % the minerals proportion in BCD. The presence of modified digestate-derived biochar (M-BCD) in a culture led to an enhanced methane production (0.402 m3kgVS-1) indicating that the specific additive exhibited a higher potential than all BCs to promote the efficiency of AD of a biomass feedstock. M-BCD also possessed the greatest capability to lessen an inhibition caused by H2S retaining the concentration of the toxic gas at levels lower than 100 ppm. On the other hand, modified BCS provoked a 9% abatement in methane yields providing evidence that nitric acid could have a neutral or slightly negative effect on the capability of a BC to improve the AD process.

Optimization and evaluation of ultra-trace amounts of lead in real samples using sol–gel based optical sensor coupled with colorimetry

The entrapment of the sensitive reagent 5-(2′-bromophenylazo)-6‑hydroxy-pyrimidine-2,4‑dione (BPAHPD) in a silica sol-gel thin film coated on a glass substrate has been investigated for the development of a highly sensitive and selective optode for the determination of lead ions. The fabrication of thin films requires tetraethoxysilane as a precursor, a sol-gel pH of 2.75, a water: alkoxide ratio of 5:1, and a BPAHPD concentration of 4.0 × 10–4 M. The effect of sol-gel parameters on the optode's sensing performance was investigated. The fabricated optode is utilized for lead ion detection over a dynamic range of 4.00–144 ng mL–1 with detection and quantification limits of 1.20 and 3.95 ng mL–1, respectively. It gave repeatable results with relative standard deviation (RSD) values of 1.90% and 1.15% for lead concentrations of 40.0 and 80.0 ng mL–1, respectively, and a response time of two minutes. Through capturing BPAHPD in a sol-gel matrix and appropriately modifying the structure of doped sol-gel, interference studies have determined that lead exhibits a high degree of selectivity. To ascertain total lead, Pb4+ was reduced to Pb2+ using a few drops of 6.00 M hydrochloric acid and a freshly prepared sodium azide solution of 2.50 % (w/v). The optode can be easily regenerated with 0.15 M of nitric acid solution. The optode has complete reversibility. Optode detection of lead in diverse vegetable, food, biological, water, and soil samples yielded favorable results when compared to other techniques.

Rice Husk Cellulose-Based Adsorbent to Extract Rare Metals: Preparing and Properties.

Adsorption is one of the common stages in the hydrometallurgy of rare metals. Its efficiency is largely determined by the quality of the sorbent used. The purpose of this work was to create an activated sorbent based on rice husk cellulose for the extraction of rhenium from aqueous solutions. Two types of cellulose were obtained by treating rice husk with a 1.5% NaOH solution (alkaline cellulose) and a nitric acid solution in ethyl alcohol (Kürschner and Hoffer cellulose). They were tested by IR, SEM, TA, TPD-MS, and XRD methods. It was found that Kürschner and Hoffer cellulose does not contain lignin and retains structural order to a greater extent. By means of this cellulose carbonization at 600 °C and activation by physical, chemical, and combined methods, a series of sorbents were prepared and studied by different methods. It was determined that the sorbent KHC4-600VA obtained by combined activation of cellulose carbonizate by water vapor at 850 °C, followed by an alkaline treatment, has the best textural characteristics: S-~1200 m2·g-1, V-1.22 cm3·g-1, and R-2.05 nm. KHC4-600VA provides 90% recovery of Re (VII) ions from aqueous solutions. According to the Freundlich model, sorption proceeds favorably on the sorbent's heterogeneous surface.

Synthesis, characterization and uptake studies of diglycolamic acid and diglycolamide analogs adsorbents for extraction of rare earth elements

Tetraalkyldiglycolamides are known for their high extracting efficiency of rare earth elements (REEs) from nitric acid solutions (1–6 mol/L). Nevertheless, solid-phase extractants based on diglycolamides (DGA) are poorly studied for REEs extraction. This paper explores the design and synthesis of novel REEs adsorbents by grafting silica with diglycolic acid-based ligands. The newly developed solid-phase materials were investigated for their potential to effectively separate REEs from various media. The functionalization of the silica with different ligands was quantified, and the adsorbents' extraction capacities and selectivity for REEs over Calcium (Ca2+), Aluminium (Al3+) and Iron (Fe3+) were evaluated. Si-NH-DGA emerged as the most efficient adsorbent for Gd3+ extraction, exhibiting a remarkable capacity of 44 mg/g at pH 4–6. However, modifications involving ether oxygen substitution with a methylamino group or sulfur led to reduced extraction efficiencies. Si-NH-DGA-NMe2 demonstrated strong binding of REEs in nitric acid solutions (1–3 mol/L HNO3) with corresponding adsorption capacities for Y3+, La3+, Gd3+ and Yb3+ being 16.3, 14.2, 22.8, and 30.2 mg/g, respectively. Furthermore, it displayed remarkable selectivity for REEs over Ca2+. The equilibrium extraction for Gd occurred within 60 min for Si-NH-DGA and Si-NH-DGA-NMe2 under their respective optimal conditions. Disodium EDTA solution demonstrated a high stripping efficiency for Gd3+ in the Si-NH-DGA-NMe2 column extraction, yielding a significant concentration factor (CF = 85). In the same column, following five cycles of loading/stripping of Gd3+, there was an average capacity loss of 6%. Si-NH-DGA-NMe2 emerged as a promising material for solid-phase extraction from concentrated nitric acid solutions, characterized by high capacity and good selectivity towards middle and heavy REEs. This structure has the potential to be further optimized for the development of a solid-phase extraction column for REEs separation and purification. The findings also highlight the potential of Si-NH-DGA-NMe2 as a candidate for REEs adsorption for potential industrial applications and the purification of acidic waste solutions.

Utilization of a novel PVC- optical sensor for high sensitive and selective determination of zinc ion in real samples

A novel and highly specific bulk membrane optode was developed for the ultra-sensitive detection of zinc(II) in biological, pharmaceutical, and water samples. The polymer inclusion membrane (PIM) utilized in this study consists of 50% polyvinyl chloride (PVC) as a base polymer, 9.00% DOP (dioctylphthalate) as the plasticizer, and 40.0% D2EHPA (di(2-ethlyhexyl)phosphoric acid) as the carrier. To facilitate the spectrophotometric determination of zinc(II), a colorimetric reagent, namely 4-(2-arsonophenylazo) salicylic acid (APASA) {1.00%, m/v}, was employed. When Zn(II) was extracted into the PIM, it led to the creation of the zinc-D2EHPA complex. This complex then underwent a reaction with APASA, resulting in the formation of a red Zn − APASA complex with a maximum absorption wavelength (λmax) of 558 nm. To optimize the response of the optode, a central composite design was employed, considering variables such as the amount of additive and reagent, response time, and pH. When operated under the specific optimal conditions, the sensor demonstrated a limit of quantification (LOQ) of 0.74 ng/mL (equivalent to 1.17 × 10−8 M) and a limit of detection (LOD) of 0.22 ng/mL (equivalent to 3.44 × 10−9 M). The optode membrane demonstrated excellent reproducibility, stability, and a relatively long lifespan, making it suitable for precise and accurate monitoring of Zn(II) ion content. Regeneration of the optode was achieved effectively using 0.25 nitric acid solution, and its response exhibited reversibility and reproducibility, showed a relative standard deviation of less than 1.33%. Moreover, the PIM-APASA optode exhibited a high level of effectiveness in accurately determining the presence of Zn(II) ions in real environmental samples.

Comparative Analysis of Cellulosic Ethanol Production from Lignocellulosic Substrate Moringa oleifera Using Kluyveromyces marxianus and Zymomonas mobilis

In the current investigation, the woody stem of Moringa oleifera was processed by chipping and milling and was subsequently exposed to a combination of pretreatments involving a 3% v/v solution of nitric acid and autohydrolysis. The simultaneous saccharification and fermentation (SSF) of the pretreated hydrolysate of M. oleifera was conducted using Zymomonas mobilis and Kluyveromyces marxianus in occurrence of commercial cellulase enzyme, Tween 80, and sodium azide. The fermentation process parameters for Z. mobilis were optimized individually, including a substrate concentration of 5% (w/v), concentration of inoculum 5% (v/v), pH 5.4, and temperature 34 °C. Similarly, for K. marxianus, the process parameters were optimized individually, with a substrate concentration of 5% (w/v), an inoculum concentration of 3% (v/v), a pH of 5.1, and a temperature of 41 °C. The highest cellulosic ethanol concentration was achieved by the micro-organism K. marxianus after a fermentation period of 96 h.

ISOTHERMAL SECTION OF THE ZrO2–HfO2–Eu2O3 SYSTEM PHASE DIAGRAM AT 1100 °C

Phase equilibria and structural transformations in the ternary ZrO2–HfO2–Eu2O3 system at 1100 °C were studied by X-ray diffraction over the entire composition range. The samples of different compositions have been prepared from nitrate acid solutions by evaporation, drying, and calcinations at 1100 °C. Fields of solid solutions based on the cubic (F) modification with fluorite-type structure and tetragonal (T) and monoclinic (M) modifications of ZrO2 (HfO2), cubic (C) modification of Eu2O3, and an ordered intermediate phase with pyrochlore-type structure, Ln2Zr2O7 (Ln2Hf2O7)(Py), were established to exist in the system. The solubility of Eu2O3 in M-HfO2(ZrO2) is pretty low and approximately less than 1 mol%, which is confirmed by XRD. The boundaries of phase fields and lattice parameters of the phases were determined. The lattice parameters for F phase vary from а = 0.5305 nm in two-phase sample (C+F) containing 6.75 mol% ZrO2–8.25 mol% HfO2–85 mol% Eu2O3 to а = 0.5283 nm for sample containing 27 mol% ZrO2–33 mol% HfO2–40 mol% Eu2O3 and to а = 0.5275 nm in two-phase sample (Py+F) containing 29.25 mol% ZrO2–35.75 mol% HfO2–35 mol% Eu2O3, and from а = 0.5232 nm in two-phase sample (Py+F), containing 32.625 mol% ZrO2–39.875 mol% HfO2–27.5 mol% Eu2O3 to а = 0.5218 nm sample containing 33.75 mol% ZrO2–41.25 mol% HfO2–25 mol% Eu2O3 and to а = 0.5176 nm in two-phase sample (F+M) containing 40.5 mol% ZrO2–49.5 mol% HfO2–10 mol% Eu2O3 along the section Eu2O3–(55 mol% HfO2–45 mol% ZrO2). The fluorite-type structure (F) is in equilibrium with all phases that exist in the ternary ZrO2–HfO3–Eu2O3 system at 1100 °C and forms substitutional solid solutions with phases of the binary systems. In the ZrO2–HfO2–Eu2O3 system, an infinite series of solid solutions form from the Ln2Zr2O7 (Ln2Hf2O7) (Py) phase. The isothermal section of the ZrO2–HfO2–Eu2O3 phase diagram at 1100 °C contains one three-phase regions (T + M + F) and six two-phase regions (F + C, two-F + Py, F + M, F + T, T + M). No new phases were found in the ZrO2–HfO2–Eu2O3 system at 1100 °C and the nature of phase equilibria was determined by the constitution of the boundary binary systems.