Aqueous Solution Of Oxalic Acid Research Articles

High-Selectivity Recycling of Valuable Metals from Spent Lithium-Ion Batteries Using Recyclable Deep Eutectic Solvents.

The recovery of valuable metals from spent lithium-ion batteries using deep eutectic solvents (DESs) is an environmentally and economically beneficial process. In this study, a method has been developed for recovering LiNi0.33Co0.33Mn0.33O2. Our process operates under mild conditions and with a little oxalic acid as a reducing agent, dissolving lithium, cobalt, manganese, and nickel completely utilizing a DES that is composed of tetrabutylammonium chloride and of monochloroacetic acid. Lithium and nickel were selectively precipitated using oxalic acid. Cobalt and manganese were precipitated as oxalates by adding an oxalic acid aqueous solution. Finally, the DES can be regenerated by evaporating the water. Importantly, valuable metals can be recovered with a 100 % yield through the process of DES recycling. This environmentally friendly and recyclable process is suitable for the recycling of spent lithium-ion batteries industry.

Determination of the Maillard reaction products in complementary rice, flour, and noodles by high performance liquid chromatography with a diode array detector

AbstractA method was established for the simultaneous determination of furosine, furanone, and four furfural compounds (5‐hydroxymethylfurfural, furfural, furyl methyl ketone, and methyl furfural) in complementary rice, flour, and noodles for infants and young children by high performance liquid chromatography with a diode array detector. The sample was extracted using oxalic acid aqueous solution as a solvent, and the protein was removed using trichloroacetic acid. Then the six Maillard reaction products were separated by an Eclipse XDB‐C18 column with a gradient elution at a flow rate of 0.6 mL/min using acetonitrile‐0.1% trifluoroacetic acid solution as the mobile phase, detected by a diode array detector and quantified by external standard method. The linear ranges of the six Maillard reaction products were 250–20000 μg/100 g with the correlation coefficients greater than 0.999, and the limits of quantification ranged from 250 to 1000 μg/100 g (S/N ≥ 10). The recoveries of the six Maillard reaction products ranged from 71.2% to 100% with a relative standard deviation of 0.9%–4.9%. The real sample analysis results showed that 5‐hydroxymethylfurfural was detected in two cookie samples, the contents of which were 335 μg/100 g and 436 μg/100 g, respectively. There are no studies on the detection of the six Maillard reaction products in rice, flour, and noodles in the previous reports. The established method provided reference for the quantification of expiration date in complementary rice, flour, and noodles for infants and young children.

Dual functional behaviour of dicationic ionic liquid as extractant and hydrophobic biphasic solvent for extraction of Pb(II) in water

Herein, it was aimed to investigate the extraction ability of hydrophobic di-cationic imidazolium-based ionic liquid with inbuilt carboxylic acid functionalities for one of the heavy metals, Pb(II) from aqueous solution. Two dicationic ionic liquids, IL-1 named 1,1′(butane-1,4-diyl)bis(3-(4carboxyphenyl)-2-methyl-1H-imidazol-3-ium) chloride and IL-2 named 1,1′(dodecane-1,12-diyl)bis(3-(4carboxyphenyl)-2-methyl-1H-imidazol-3-ium)chloride tailored with (CH2)n bridging spacer chains, n = 4 and n = 12 respectively were synthesized. The Pb(II) displayed extraction percentages greater than 90% with both the aqueous biphasic system of IL-1 and IL-2. An efficient back-stripping of the Pb(II) metal ion was done using with aqueous solution of oxalic acid. Calcination of lead oxalate salt obtained showed highest purity of PbO confirmed by PXRD and EDX data. The established experimental condition with the synthesized ionic liquids is a distinguished one as no salting out agent, no extra extracting agents other than the synthesized ionic liquids were used. Moreover, the regeneration of the ionic liquid (IL-2), and back stripping of Pb(II) as oxalate salt makes this system an efficient one with negligible loss of the ionic liquid (IL-2) into the aqueous medium thus obliging the standards of environment-friendly sustainable development.

Application of a flexible memristor in self-color electronics and its depth mechanism analysis

Memristor has a high-density information storage capability and can manipulate a large amount of data computing in parallel, so it can be applied in neuromorphic computing. The advanced intelligent applications are one of the major breakthroughs made in the past decade based on the memristor's research. In this work, amorphous Nb2O5 film as functional layers on flexible niobium (Nb) foil were fabricated by anodic oxidation in oxalic acid aqueous solution. A broad spectrum of well-defined color was acquired by varying the anodic voltage during oxidation of the Nb foil. The results of spectroscopic ellipsometry (SE) tests show that the Nb2O5 layers with various colors have different thickness. The willow yellow Nb2O5 film with a thickness of ∼85 nm based memristor show an excellent memristive memory behavior. Finally, it was proposed that the potential well of the ionization center tilts under the external electric field, which causes the probability of charge to escape along and against the direction of the external electric field to explain the memristive effect of the device. This work opens up a new method for fabricating the flexible memristor, which provides the potential applications for next generation self-color electronics.

Precipitation of Ferrous Oxalate from Ferrous Ammonium Sulfate in Oxalic Acid Solution

A kinetic study was conducted experimentally for the precipitation of ferrous oxalate. The ferrous oxalate, in the form of dihydrate (FeC2O4·2H2O), was produced by the acidic dissolution of ferrous ammonium sulfate (Fe(NH4)2(SO4)2) in an aqueous solution of oxalic acid, and then precipitated by nucleation and particle growth from supersaturated solution. The effect of the concentration of ferrous ammonium sulfate and oxalic acid as raw materials was investigated on the kinetics of the ferrous oxalate precipitation. Temperature was kept constant at 25 °C. The surface morphology, atomic compositions, and crystal phase were characterized for the ferrous oxalate precipitate collected. As the initial concentration of ferrous ammonium sulfate increased, the initial precipitation of ferrous oxalate occurred faster. The concentration of oxalic acid did not significantly affect the rate of precipitation of ferrous oxalate. The experimental behavior of ferrous oxalate precipitation was modeled with first-order models of reaction kinetics.

Synthesis and application of chloroacetamides in pyridinium based ionic liquid for high temperature extraction of uranyl ion: A novel and 'green' approach for extractive mass transfer at elevated temperature

Two different chloroacetamides viz 2-chloro-N-methyl-N-phenylacetamide (MACA) and 2-chloro-N-(3-methylpyridin-2-yl)acetamide (AMPCA) have been synthesized and applied for the extraction of uranyl ions from acidic feed. 1-Ethyl-2-methylpyridinium bis(trifluoromethylsulfonyl)imide ionic liquid (IL) has been used at elevated temperature for liquid–liquid biphasic mass transfer. An effort has also been made to study the mechanism of extraction, kinetics, thermodynamics, speciation, radiolytic stability and elution behavior of UO22+. The investigation revealed the predominance of ‘cation exchange’ mechanism. The D values in 2-chloro-N-methyl-N-phenylacetamide (MACA) were found to be more than that of 2-chloro-N-(3-methylpyridin-2-yl)acetamide (AMPCA). The species were found to be[(UO2(NO3)(MACA)2]+ and [(UO2(NO3)(AMPCA)2]+. Back extraction studies using aqueous solution of oxalic acid and sodium carbonate revealed that, the stripping of uranyl ion from AMPCA in ionic liquid was better than that of MACA. However, MACA exhibited better radiolytic stability as compared to AMPCA in ionic liquid. To understand the complexation of UO22+ with MACA and AMPCA, theoretical calculations were carried out.

Crystallization of Form II Paracetamol with the Assistance of Carboxylic Acids toward Batch and Continuous Processes.

Form II paracetamol has captured the interest of researchers due to its improved compressibility. However, its low stability has made it difficult to be produced on a large scale with good reproducibility. In the present study, the selective polymorphic formation of paracetamol was carried out by cooling crystallization with four types of additives: adipic acid, fumaric acid, oxalic acid, and succinic acid. It was found that: (1) the more additives that were added, the higher the probability of forming Form II paracetamol; (2) Form II paracetamol could be induced by seeding the paracetamol aqueous solution with Form II paracetamol and fumaric acid crystals, and not the other three carboxylic acids; (3) a new solution complex of paracetamol–oxalic acid, evidenced by the solubility diagram, was responsible for the selective nucleation of Form II paracetamol in the oxalic acid aqueous solution; and (4) the range of the degree of supersaturation for nucleating Form II paracetamol was extended with the assistance of oxalic acid or fumaric acid. In large-scale crystallization, Form II paracetamol was produced by the continuous crystallization of 44 mg of paracetamol/mL in 50 wt% of fumaric acid aqueous solution with a flow rate of 150 mL/min.

Kinetics of Reductive Dissolution of a Magnetite Specimen Using Oxalic Acid

The removal of radionuclides from the primary coolant system of nuclear power plants occurs with the dissolution of corrosion metal oxide layers deposited with the radionuclides. Kinetic dissolution experiments were conducted with a synthetic magnetite specimen in the form of a thin plate using an aqueous solution of oxalic acid as a reducing agent. The effects of acid concentration and temperature were investigated on the kinetics of the reductive dissolution of a magnetite specimen. In particular, the kinetic experiments were performed in a wide temperature range from low (57 °C) to high (120 °C), above the normal boiling point of water. The dissolution of magnetite increased with increasing acid concentration and temperature. The acid concentration dependence of the dissolution reaction rate of Fe at a given temperature was correlated with the nth power of the oxalic acid concentration. Additionally, the temperature dependence of the dissolution reaction rate of Fe at a fixed oxalic acid concentration was studied with an Arrhenius-type equation.

Catalytic Ozonation of Oxalic Acid in Aqueous Solution in the Presence of Manganese Ions

Catalytic Ozonation of Oxalic Acid in Aqueous Solution in the Presence of Manganese Ions

Leaching of Ibute-Nze kaolin iron-oxide impurity with oxalic acid process optimization of dissolution conditions using response surface methodology

The goal of this research was to remove iron oxide from Ibute-Nze kaolin by dissolving the clay mineral in an aqueous oxalic acid solution and optimizing the process. The chemical composition of the raw and modified clay was determined using x-ray fluorescence, and the morphology of the solid sample was determined using a scanning electron microscope. The best conditions for the oxalic acid leaching of iron-oxides impurity from Ibute-Nze kaolin were determined using response surface methodology based on Box-Behnken design. The studies were carried out within the following process parameter ranges: 40–90 leaching temperature; 0.075-0.355mm particle size; 1–6 mol/dm3 acid concentration; 0.02–0.12 g/cm3 kaolin sample to acid ratio and 30-240 min contact time. The characterization revealed that Ibute-Nze clay is kaolinitic in nature and calcination at 750 opens more pores for its leaching. According to the analysis of variance, a second-order polynomial regression equation provided the best fitting for the experimental data. The predicted and experimental response values were shown to be correlated (R2 = 0.9276) in the experimental runs. The following were found to be the best conditions for the leaching process variables: 83.2051 leaching temperature, 0.0827mm particle size, 3.6179mol/dm3 acid concentration; 0.0287g/cm3 kaolin to acid ratio and 217.932min reaction time. The chemical leaching process was 92.6035 per cent under these conditions, which made the clay good for industrial applications.

One-Step Synthesis of Iron and Titanium-Based Compounds Using Black Mineral Sands and Oxalic Acid under Subcritical Water Conditions

Black mineral sands are widely used to obtain titanium dioxide, titanium, and, more recently, a variety of iron–titanium oxide nanostructures. Highly corrosive mineral acids or alkalis are commonly employed for this purpose. Hence, it is desirable to find eco-friendly ways to process these minerals, deriving high-added value materials. In this study, an Ecuadorian mineral sand precursor (0.6FeTiO3∙0.4Fe2O3 solid solution) was treated with oxalic acid aqueous solutions under subcritical water conditions. The synthesis was conducted in a batch reactor operating at 155 °C, 50 bar, and 700 rpm for 12 h, varying the oxalic acid concentration (0.1, 0.5 to 1.0 M). The as-obtained compounds were physically separated, dried, and analyzed by X-ray powder diffraction, scanning electron microscopy, and Raman spectroscopy. The characterization showed that the precursor was completely converted into two main products, ferrous oxalate, and titanium dioxide polymorphs. Rutile was always found in the as-synthesized products, while anatase only crystallized with high oxalic acid concentrations (0.5 and 1.0 M). These results open the possibility to develop more sustainable routes to synthesize iron and titanium-based materials with promising applications.

Identification of a Two-Coordinate Iron(I)-Oxalate Complex.

Exotic oxidation states of the first‐row transition metals have recently attracted much interest. In order to investigate the oxidation states of a series of iron–oxalate complexes, an aqueous solution of iron(III) nitrate and oxalic acid was studied by infrared free liquid matrix‐assisted laser desorption/ionization as well as ionspray mass spectrometry. Here, we show that iron is not only detected in its common oxidation states +II and +III, but also in its unusual oxidation state +I, detectable in both positive‐ion and in negative‐ion modes, respectively. Vibrational spectra of the gas phase anionic iron oxalate complexes [FeIII(C2O4)2]−, [FeII(C2O4)CO2]−, and [FeI(C2O4)]− were measured by means of infrared photodissociation spectroscopy and their structures were assigned by comparison to anharmonic vibrational spectra based on second‐order perturbation theory.

Anodizing of Hydrogenated Titanium and Zirconium Films.

Magnetron-sputtered thin films of titanium and zirconium, with a thickness of 150 nm, were hydrogenated at atmospheric pressure and a temperature of 703 K, then anodized in boric, oxalic, and tartaric acid aqueous solutions, in potentiostatic, galvanostatic, potentiodynamic, and combined modes. A study of the thickness distribution of the elements in fully anodized hydrogenated zirconium samples, using Auger electron spectroscopy, indicates the formation of zirconia. The voltage- and current-time responses of hydrogenated titanium anodizing were investigated. In this work, fundamental possibility and some process features of anodizing hydrogenated metals were demonstrated. In the case of potentiodynamic anodizing at 0.6 M tartaric acid, the increase in titanium hydrogenation time, from 30 to 90 min, leads to a decrease in the charge of the oxidizing hydrogenated metal at an anodic voltage sweep rate of 0.2 V·s−1. An anodic voltage sweep rate in the range of 0.05–0.5 V·s−1, with a hydrogenation time of 60 min, increases the anodizing efficiency (charge reduction for the complete oxidation of the hydrogenated metal). The detected radical differences in the time responses and decreased efficiency of the anodic process during the anodizing of the hydrogenated thin films, compared to pure metals, are explained by the presence of hydrogen in the composition of the samples and the increased contribution of side processes, due to the possible features of the formed oxide morphologies.

Dipicolinamide functionalized titania for highly efficient sorption of tetra and hexavalent actinide

Dipicolinamide functionalized titania particles have been synthesized for efficient decontamination of uranyl and thorium ions from aqueous acidic waste solution. Langmuir isotherm was found to be predominating with maximum sorption capacity of 125 mg/g for Th and 111 mg/g for U, respectively. The sorption was found to follow pseudo 2nd order kinetics predominately, with rate constant 8.6E−04 mg g−1 min−1 for Th and 6.1E−04 mg g−1 min−1 for U, respectively. Up to 200 kGy of gamma irradiation, not much deterioration in extraction performance of sorbent material was observed. Three contacts of 0.1 M aqueous solutions of oxalic acid and sodium carbonate were found to be effective in quantitative elution of Th4+ and UO22+ from the loaded sorbent, respectively. The sorption of U and Th on dipicolinamide functionalized titania was evidenced by SEM images, elemental mapping and the EDX. Theoretical investigation revealed that, the solution phase free energy of sorption (ΔGsol) was higher for Th4+ (−114.1 kcal mol−1) compared to UO22+ (−80.41 kcal mol−1).

Optimized Organosolv Pretreatment of Biomass Residues Using 2-Methyltetrahydrofuran and n-Butanol

Wheat straw and eucalyptus residues were pretreated in a biphasic system, constituted of butanol (n-butanol) or 2-methyltetrahydrofuran (2M-THF) and aqueous oxalic acid solutions. The pretreatments were carried out in a 300 mL Parr reactor (Autoclave Buchi Limbo-li®) with a solid load of 5 wt.%, the temperature in the range 140–180 °C, oxalic acid load from 0 to 10 wt.% and a duration of 30–90 min. The obtained slurry was then fractionated in three streams: the aqueous phase which contained solubilized hemicellulose, the organic phase which contained the solvated lignin, and the solid residue which contained cellulose. The solid was hydrolyzed using a commercial mix of enzymes to assess cellulose digestibility and glucose production. The pretreatment was optimized to maximize the purity of the cellulose and hemicellulose fractions and the glucose recovery as free sugar. The optimization was done by using an experimental design and response surface methodology. The mass flow details of the four optimized processes were obtained. In terms of biomass fractionation, butanol demonstrated significant advantages over 2M-THF in the same range of process conditions as shown by the recovery yield of free glucose which reached 98% of the theoretical value with butanol but was 67% with 2M-THF. Tests at low temperature and low enzyme loading highlighted the importance of the solvent choice over the operating conditions. 2M-THF showed interesting performances only in the delignification step, with 90% efficiency for the straw. Regarding the use of different feedstock, fractionation and recovery were generally higher for wheat straw than for eucalyptus wood residues.

Mechanism of catalytic ozonation in expanded graphite aqueous suspension for the degradation of organic acids

ABSTRACT In this study, expanded graphite (EG) was prepared by the oxidation and intercalation of the natural flake graphite using perchloric acid and potassium permanganate at different expansion temperatures (300, 400, 500, and 600°C), and were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). EG prepared at 500°C was found to be highly effective for the mineralization of oxalic acid aqueous solution during ozonation at pH 3, which was ascribed to the formation of hydroxyl radicals from the surface reaction of surface hydroxyl groups on EG with ozone. The performance of expanded graphite in this catalytic system was basically unchanged after three repeated use. The presence of Cl−, , and could inhibit the degradation of oxalic acid in catalytic ozonation with EG. Degradations of oxamic acid and pyruvic acid in catalytic ozonation with EG were pH-dependent, which were lower than that of oxalic acid. The degradations of oxalic acid and oxamic acid were identified as mineralization process by the determination of TOC, while pyruvic acid may transform into organic products such as acetic acid by O3/EG. Manganese ion (Mn2+) could promote the degradation of oxalic acid by O3/EG at pH 3 because permanganate was produced by O3/EG in oxalic acid solution and then reacted with oxalic acid readily at acidic pH. Catalytic ozonation by EG exhibited great application potential for the destruction of refractory organic compounds.

Finishing Properties of Poly Urethane Coating on Bleached and Ammonia Fumigated Mango Wood Surface

Aims: The impact of bleaching chemicals on the gloss and film thicknesses of poly urethane (PU) coated surface of mango wood (Mangifera indica) with ammonia fumigation and an exposure towards sunlight was investigated
 Study Design: Thirty six wood samples of size 10.6 cm (length) C 7.62 cm (width) were prepared from 2.5 cm thick kiln dried mango wood (Mangifera indica). Specimens were divided into six groups, each group having 6 samples for the study.
 Place and Duration of Study: The experiment was carried out in year 2016 at the Laboratory of Forest Product Division, Forest Research Institute, Dehradun, Uttarakhand, India.
 Methodology: All the samples were sanded with 80 grit size sand paper and coated with poly urethane. Two chemicals were used for bleaching purpose like an aqueous solution of oxalic acid (H2C2O4) was prepared with 30% concentration (by mixing 42.9 g of the solute in 100 ml of hot water) and a commercially available Hydrogen peroxide (H2O2) was used as such (30%). For the purpose of bleaching, these chemicals were applied on to the sanded surfaces using brush at room temperature. The bleached sample surfaces were allowed to dry before proceeding to the next step. The PU (Poly Urethane) coated samples were treated with ammonia fumigation before and after bleached with the two chemicals. Ammonia fumigation was carried out in a fumigation chamber for 24 hours for all the samples (except T1).
 Results: On exposure to natural sunlight for 60 hours, all the samples showed reduction in film thickness in PU coating but in a wide range of 2.8 % to 11.4%. The highest loss of coating thickness was shown by samples which were neither fumigated nor bleached. Among the fumigated samples, those bleached with oxalic acid resulted in high film thickness loss. Samples bleached with hydrogen peroxide after ammonia fumigation resulted in least film thickness reduction. Both ammonia fumigation and bleaching in general brought down the original gloss of poly urethane coating. The gloss value reduced as expected on exposure to sunlight. Bleaching by hydrogen peroxide prior to ammonia fumigation resulted in highest loss in gloss
 Conclusion: The un-fumigated and unbleached surface resulted in minimum gloss reduction due to long exposure to sunlight.

Effect of oxalic acid on vase life and antioxidative activities of ‘Mero Star’ cut lily flowers

Lily (Lilium L. hybrids) is sub-tropical cut flower that can be grown in open place or in green house and has consumer demand in local as well as in offshore markets. Short vase life, postharvest decay of flowering petals, activities of oxidative enzymes, malondialdehyde contents, electrolyte leakage and low water ratio are the main problems in marketing of cut lilies. This study was carried out to investigate the effect of oxalic acid (OA) treatments on vase life (12 days) and postharvest quality of ‘Mero Star’ cut lily flowers. The flowering stems were placed in 2, 4 and 6% aqueous solution of OA for 12 days at 20±2 °C with 70±5% relative humidity. Flowers placed in 6% OA solution exhibited longest vase life and flower diameter with higher relative water content and increased fresh weight and reduced flower decay. Reduced malondialdehyde contents and electrolyte leakage with higher activities of catalase, superoxide dismutase and peroxidase enzymes were also noted in 6% OA-treated flowers. In conclusion, exogenous postharvest application of 6% OA extended vase life and maintained postharvest quality of cut flowers by reducing electrolyte leakage and malondialdehyde contents with higher antioxidative enzymes activities.

Optical Properties of Porous Alumina Assisted Niobia Nanostructured Films-Designing 2-D Photonic Crystals Based on Hexagonally Arranged Nanocolumns.

Three types of niobia nanostructured films (so-called native, planarized, and column-like) were formed on glass substrates by porous alumina assisted anodizing in a 0.2 M aqueous solution of oxalic acid in a potentiostatic mode at a 53 V and then reanodizing in an electrolyte containing 0.5 M boric acid and 0.05 M sodium tetraborate in a potentiodynamic mode by raising the voltage to 230 V, and chemical post-processing. Anodic behaviors, morphology, and optical properties of the films have been investigated. The interference pattern of native film served as the basis for calculating the effective refractive index which varies within 1.75–1.54 in the wavelength range 190–1100 nm. Refractive index spectral characteristics made it possible to distinguish a number of absorbance bands of the native film. Based on the analysis of literature data, the identified oxide absorbance bands were assigned. The effective refractive index of native film was also calculated using the effective-medium models, and was in the range of 1.63–1.68. The reflectance spectra of all films show peaks in short- and long-wave regions. The presence of these peaks is due to the periodically varying refractive index in the layers of films in two dimensions. FDTD simulation was carried out and the morphology of a potential 2-D photonic crystal with 92% (wavelength 462 nm) reflectance, based on the third type of films, was proposed.

Dissolution of Iron Oxides Highly Loaded in Oxalic Acid Aqueous Solution for a Potential Application in Iron-Making

Dissolution of Iron Oxides Highly Loaded in Oxalic Acid Aqueous Solution for a Potential Application in Iron-Making