Oxalic Acid Solution Research Articles

Preparation of Magnesium Titanate by Using Magnesium Chloride a Byproduct of Titanium Plant

This study explores the preparation of magnesium titanate using magnesium chloride, a byproduct of the titanium production plant as a precursor. The synthesis involves the reaction of MgCl2 with titanium tetrachloride under controlled thermal conditions. Initially, MgCl2 and TiCl4 are thoroughly mixed in stoichiometric proportions with an excess of oxalic acid solution to produce magnesium titanyl oxalate. The mixture is then subjected to a calcination process at temperatures ranging from 300 °C to 1000 °C in an oxygen-rich environment. The physicochemical properties of the synthesized MgTiO3 were analyzed using EDS, XRD, TG/DTA, SEM, and particle size analysis. This comprehensive set of analytical techniques provides a thorough understanding of the elemental, structural, thermal, morphological and physical characteristics of magnesium titanate. The formation of pure magnesium titanate is confirmed at temperatures above 800 °C, with lower temperatures leading to the presence of intermediate phases such as MgTi2O5. The synthesized MgTiO3 exhibits a homogeneous microstructure with well-defined grain boundaries, indicating successful preparation of the desired ceramic material.

High temperature long-lasting corrosion inhibition mechanism of sodium dodecyldiphenyl ether disulfonate on ADC12 aluminum alloy in oxalic acid solution

The high temperature corrosion inhibition mechanism of sodium dodecyl diphenyl ether disulfonate (MADS) on ADC12 aluminum alloy in oxalic acid solution at 80 °C was investigated using electrochemical measurements, surface characterization and theoretical computations. The results manifested that MADS still had excellent performance in high-temperature oxalic acid solution, and was a highly efficient and long-lasting corrosion inhibitor with an optimal corrosion inhibition efficiency (ƞ) of 90.90 %. With increasing soaking time, the ƞ increased to 98.70 %. MADS molecule adsorbed on the aluminum alloy surface in an L-shaped walking scooter configuration through physicochemical adsorption to form a dense, thin and stable hydrophobic film, inhibiting the formation of aluminum oxalate and Al2O3, and protecting it from corrosion.

Dissolution process and mechanism of montmorillonite in oxalic acid and sulfuric acid media at various pH levels

The dissolution of silicate minerals plays a crucial role in many natural geological processes. In order to better comprehend the reaction mechanisms and dissolution characteristics of montmorillonite in different acidic systems, the effects of interfacial reactions of montmorillonite with oxalic and sulfuric acid solutions at various pH levels on the ionic dissolution, crystal structure, and micro-morphology were studied, and the morphology of aluminum and saturation index of secondary mineral were simulated. It was shown that the dissolution amounts of Mg2+, Al3+ and Si4+ in montmorillonite structure decreased with the increase of pH value, which reflected the dependence of montmorillonite dissolution on the pH value of solution. The dissolution percentages of Mg2+, Al3+ and Si4+ after the reaction of montmorillonite with oxalic acid solution were greater than those in sulfuric acid solution, and the highest dissolution rate of Al3+, indicated that both ligands and protons attacked the surface sites of montmorillonite and accelerated the dissolution of ions. Moreover, oxalate ligands exerted specific binding effects on Al3+ ions. While reacting with oxalate and sulfate, the tetrahedral, octahedral and interlayer cations of montmorillonite exhibited the non-stoichiometric and inconsistent dissolution. The oxalate ligands have a strong complexation effect on Al3+, so that Al3+ in oxalate solution exists in the form of aluminum oxalate complex, which reduces the effective concentration of Al3+ in solution and promotes the dissolution of Al3+ in montmorillonite structure. The Mg2+ ions settled at octahedral substitution sites possessed weak stability, while those from the interlayer featured strong interlayer interchangeability, demonstrating the dissolution percentage up to 10.85 % and 8.62 % even in oxalic and sulfuric acid solutions at pH of 6.5. All secondary mineral phases in the solution were undersaturated, making the montmorillonite dissolution difficult to balance. Montmorillonite has a high cation exchange capacity, which makes it have a strong buffer capacity to exogenous acids. This study helps to explain the dissolution process of montmorillonite in inorganic and organic acid solutions at different pH value.

Adsorptive-Photocatalytic Composites of α-Ferrous Oxalate Supported on Activated Carbon for the Removal of Phenol under Visible Irradiation.

Adsorptive-photocatalytic composites based on activated carbon (AC) and α-ferrous oxalate dihydrate (α-FOD) were synthesized by an original two-step method and subsequently used for the removal of phenol from aqueous solutions. To obtain the composites, ferrotitaniferous black mineral sands (0.6FeTiO3·0.4Fe2O3) were first dissolved in an oxalic acid solution at ambient pressure, and further treated under hydrothermal conditions to precipitate α-FOD on the AC surface. The ratio of oxalic acid to the mineral sand precursor was tuned to obtain composites with 8.3 and 42.7 wt.% of α-FOD on the AC surface. These materials were characterized by X-ray powder diffraction, scanning electron microscopy, and the nitrogen adsorption-desorption method. The phenol removal efficiency of the composites was determined during 24 h of adsorption under dark conditions, followed by 24 h of adsorption-photocatalysis under visible light irradiation. AC/α-FOD composites with 8.3 and 42.7 wt.% of α-FOD adsorbed 60% and 51% of phenol in 24 h and reached a 90% and 96% removal efficiency after 12 h of irradiation, respectively. Given its higher photocatalytic response, the 42.7 wt.% α-FOD composite was also tested during successive cycles of adsorption and adsorption-photocatalysis. This composite exhibited a reasonable level of cyclability (~99% removal after four alternated dark/irradiated cycles of 24 h and ~68% removal after three simultaneous adsorption-photocatalysis cycles of 24 h). The promising performance of the as-prepared composites opens several opportunities for their application in the effective removal of organic micropollutants from water.

Physiological and sanitary quality of sorghum seeds under the effect of oxalic and salicylic acid

Sorghum is one of the world's most important cereal crops, but it is susceptible to several diseases, particularly fungal diseases, with seeds being the main vehicle for dissemination. The objective of this study was to evaluate the effects of salicylic acid (SA) and oxalic acid (OA) on the physiological and sanitary quality of sorghum seeds. The seeds of Sorghum bicolor (L.) were immersed for 1 hour in solutions of OA (0.5, 1.0, 1.5, and 2.0 mM) and SA (0.5, 1.0, 1.5, and 2.0 mM). A treatment with Captan® fungicide was also used, and the control group was immersed in distilled H2O for 1 hour. Variables from seed vigor tests and fungal incidence tests were evaluated. The control group showed the highest germination rate. However, among the treatments, the doses of 1 mM OA and 0.5 mM SA resulted in higher germination in the first germination count. The application of 1 mM OA and both doses of SA (0.5 mM and 1 mM) promoted a greater seedling vigor index (GVI). Seeds treated with 1 mM OA and doses of 0.5, 1, 1.5, and 2.0 mM SA, as well as those treated with fungicide, had the highest emergence rates, and with 1.5 mM SA, the highest length of the longest root (LVEI). Seedlings from seeds treated with 0.5, 1, and 1.5 mM SA and with 0.5 and 1.5 mM had the highest coleoptile length (CPA). The 0.5 mM dose of SA reduced the incidence of Aspergillus flavus, and the doses of 2 mM OA and 1, 1.5, and 2 mM SA reduced the incidence of Rhizopus stolonifer to 0%. SA provided the best physiological and health effects for sorghum seeds, making it the best treatment.

CTAB-induced synthesis of two-dimensional copper oxalate particles: using l-ascorbic acid as the source of oxalate ligand.

Copper oxalate is typically synthesized through a precipitation reaction involving copper salts mixed with oxalic acid or oxalate solutions. However, in this study, we were successful in synthesizing well-formed square-like copper oxalate particles under liquid-phase conditions at ambient temperature and pressure using ascorbic acid as the source of the oxalic acid ligand. The addition of cationic surfactant cetyltrimethylammonium bromide (CTAB) caused the morphology of copper oxalate particles to undergo a transition from three-dimensional to two-dimensional. And the inhibition of the assembly of primary copper oxalate nanocrystals along the [001] direction became stronger with the increase of CTAB concentration. The impact of CTAB on the crystallization, growth, and self-assembly processes of primary copper oxalate nanocrystals was analysed using various testing methods. Based on these analyses, the possible mechanism of CTAB-induced synthesis of two-dimensional copper oxalate particles was finally proposed.

Hydrogen bonding-based deep eutectic solvents for choline chloride/sulfamide and its application in the recycling of precious metals

The depletion of natural resources for precious metals is occurring as the economy expands, and conventional recovery techniques often involve the use of hazardous reagents. We have successfully developed a novel deep eutectic solvent, choline chloride/sulfamide, which exhibits exceptional efficiency in forming a highly effective deep eutectic dissolution reagent with dibromohydantoin for the efficient recovery of precious metals. The acidity provided by sulfamide and the oxygen negative ions generated by choline chloride jointly initiate an attack on the N-Br bond in dibromohydantoin. Bromine radicals and Br2 together promote the oxidation of precious metals. The Cl- and Br- ions form complexes to generate AuCl2Br2-, which effectively stabilizes the Au3+ species in solution. Under optimal reaction conditions, Au0 can be completely dissolved within 25 minutes. The average rate of gold dissolution in this DES dissolution reagent was 10,235.9 mg Au/(h·mol DBD), which is more than 200 times the average rate of gold dissolution in conventional cyanide. Moreover, DES dissolution reagent allows for recycling of the precious metal up to 6 times with dissolution rates consistently above 95 %. By adding it into an oxalic acid solution, the gold complex can be reduced to Au0 to achieve recycling of precious metals.

Corrosion inhibition, long-term and adsorption mechanisms of humic acid on ADC12 aluminum alloy in oxalic acid solution

Corrosion inhibition, long-term and adsorption mechanisms of humic acid on ADC12 aluminum alloy in oxalic acid solution

Optimization of rare earth magnet recovery processes using oxalic acid in precipitation stripping: Insights from experimental investigation and statistical analysis

Recycling the valuable metals found in spent permanent magnets (REPMs) poses a significant global challenge for the future. This study examines the efficiency of back extraction of rare earth elements (REEs) by oxalic acid solution from di-(2-ethylhexyl) phosphoric acid (D2EHPA) in recycling REPMs. To evaluate the efficiency of this process, several experiments were carried out using designed BOX-Behnken methodology to investigate the effects of various operational and chemical parameters, including stripping solution to loaded organic phase volume ratio (in the range of 1.0–2.0), oxalic acid concentration (ranging from 0.25 to 0.75 M), the stirring rate (ranged between 150 and 350 rpm), and stripping time (ranging from 15 to 45 min) on the REEs recovery and the purity of final production. Analysis of variance was applied to rigorously examine the results statistically. The results showed that more than 85 % of light and 80 % of heavy REEs can be recovered under optimal conditions. Moreover, the final product contained 43.5 % REEs and approximately 0.1 % iron. The stripping experiment using phosphoric acid as the reagent demonstrated ∼57 % light and ∼4 % heavy REEs recovery. Additionally, the recyclability of the organic phase showed its effective reuse for up to four cycles. This study underscores significant progress in the selective recovery of rare earth elements through a relatively straightforward process consuming mild reagents.

The Effect of Modified Material in Screen-Printed Carbon Electrode for Oxalic Acid Detection

In this study, we investigated the effect of modified material on screen-printed carbon electrode (SPCE) for detection of oxalic acid. The SPCE was modified with (1) carbon conductive ink and (2) combination of carbon conductive ink and nickel nanoparticles (Ni-NPs). Modification process of (1) was conducted using drop-cast method by adding a mix of carbon conductive ink and nickel nanoparticles (1:1) on the surface of SPCE. Modified SPCE was then dried and stored in desiccator. Performance test of SPCE with and without modification was carried out using cyclic voltammetry (CV) method. The CV scan was done at the range of-0.5 to 1.5 V with scan rate of 100 mV/s in 20 mM oxalic acid solution. The result showed that carbon conductive ink and nickel nanoparticles mix (1:1) modified SPCE could be used to detect oxalic acid on potential 1.2 V.

Extraction of phosphorus from sewage sludge ash by electrodialysis combined with wet-chemical extraction

ABSTRACT Phosphorus (P) recovery from sewage sludge ash (SSA) is considered to be an effective method for P recovery. In this work, P extraction and the removal of heavy metals were realized by electrodialysis. Low-cost, easily available, and environmentally friendly plant extracts were applied as suspension to reduce the inevitable secondary pollution. And the feasibility of using plant extracts was analysed by comparing with using deionized water (DI) and oxalic acid (OA) solution. When SSA was suspended in different solutions (DI, OA, and three plant extracts – Hovenia acerba (HA), Saponin (SA) and Portulaca oleracea (PO)), the effects of reaction time and plant extract concentration on P extraction and heavy metal separation of SSA under ED treatment were compared. After the process of electrodialysis, compared to other experimental groups, electrodialysis with plant extracts obtained more P released from SSA, but less P migrated to the anode chamber. However, when SSA was suspended in PO at a concentration of 80 g/L, the proportion of P transferred from SSA to the anode chamber can still reached 37.86%. In addition, the use of plant extracts as suspension had a positive effect on the removal of heavy metals, but its effect was lower than that of the oxalic acid-treated experimental group. The results indicated that the use of plant extracts for wet-chemical extraction combined with electrodialysis promoted the removal of heavy metals and the extraction of P from SSA, which is a feasible option.

Comparative study on ionic dissolution and structural changes of montmorillonite, kaolinite, and muscovite during interfacial reactions with oxalic acid solution

Comparative study on ionic dissolution and structural changes of montmorillonite, kaolinite, and muscovite during interfacial reactions with oxalic acid solution

Demineralization of Oxalic Acid Solutions by Anodic Oxidation in a Stirred Tank Electrochemical Reactor: Experimental and Modeling Study

Demineralization of Oxalic Acid Solutions by Anodic Oxidation in a Stirred Tank Electrochemical Reactor: Experimental and Modeling Study

Study on the Characteristics and Mechanism of Shield Tunnel Mud Cake Disintegration in Complex Red-Bed Geology

The complex red-bed geology is primarily composed of iron-rich sedimentary rock layers with clay minerals as a major component. The soil water content exceeds 30%, and its high viscosity and water content lead to the easy formation of mud cake on the cutterhead, endangering the safety and progress of construction, which poses a significant challenge for tunnel boring machines (TBMs). The use of dispersants to eliminate mud cake is a common method in engineering projects. This paper presents an improved disintegration experiment instrument to study the disintegration characteristics of mud cake from the red-bed geology under different dispersant solutions, proposing a dispersant formulation suitable for the red-bed geology of the Haizhu Bay Tunnel project. The results indicate that mud cake samples exhibit a moderate disintegration effect in pure water. Furthermore, it has been observed that the disintegration effect decreases as the thickness of mud cake increases. Sodium silicate solution was not suitable for treating the red-bed geological mud cake, while sodium hexametaphosphate and oxalic acid solutions had a good promoting effect on the disintegration of red-bed geological mud cake. However, there was a threshold for the dispersant concentration; exceeding this threshold actually worsened the disintegration effect. Ultimately, the engineering application of a 10% oxalic acid solution, which proved effective in disintegrating the mud cake, significantly enhanced the excavation efficiency in the Haizhu Bay Tunnel project.

High-Speed Thermo-Compression Sinter-Bonding Properties in Air of a Paste Containing Dendritic Cu Particles Having Oxalate Skins

To enhance the sinter-bonding speed of Cu dendrite particle-based paste, the particles were surface-treated with oxalic acid solution. This treatment transitioned the particle surface from an oxide layer to a CuC 2 O 4 phase, which suppressed the oxidation of Cu until thermal decomposition between 284-315 °C generating Cu nanoparticles. Using the surface-treated Cu dendrite particle-based paste, sinter bonding at 320 °C under 5 MPa pressure in air provided a sufficient shear strength of 23.4 MPa in just 60 s, reaching the maximum of 28.7 MPa after 180 s. The in situ generated Cu nanoparticles from the thermal decomposition of CuC<sub>2</sub>O<sub>4</sub> directly contributed to the very rapid sintering-bonding behavior at 320 °C. However, the bondings at 300 °C and 350 °C showed poorer bonding characteristics than that of before treatment, indicating that the surface treatment strategy for forming CuC<sub>2</sub>O4 skins is effectively implemented by appropriately setting the following sinter-bonding temperature.

STUDY ON THE PERFORMANCE OF ANODIZED COATING PREPARED ON 2024 ALUMINUM ALLOY VIA PULSE ANODIZING

Different anodized coatings are prepared on the surface of 2024 aluminum alloy from different solutions by pulse anodizing to improve corrosion resistance and hardness. The thickness, roughness, structure, hardness, surface morphology, and corrosion resistance of different anodized coatings are studied. It is found that the anodized coating is composed of a porous layer on the surface and a nonporous barrier layer inside, showing the structure of [Formula: see text]-Al2O3 and [Formula: see text]-Al2O3. The anodized coating prepared from sulfuric acid solution mixed with oxalic acid and glycerol has a larger thickness and higher hardness. The surface morphology of the anodized coatings is porous. The thickness of the anodized coating prepared from oxalic acid solution is small and the pore distribution is not uniform. However, the anodized coating obtained from sulfuric acid solution mixed with oxalic acid and glycerol has the smallest average pore size of 6.38[Formula: see text]nm and ordered pore distribution, resulting in the best corrosion resistance.

High temperature corrosion behavior of ADC12 aluminum alloy in oxalic acid solution

High temperature corrosion of ADC12 aluminum alloy in oxalic acid solution was investigated using weight loss, electrochemical measurements, surface technologies. The results showed that at room temperature, the aluminum alloy exhibited localized corrosion, while at high temperatures, it exhibited uniform corrosion. As the temperature rose from 30 °C to 90 °C, the rapid dissolution of its passivation film led to a 70.19% increase in the corrosion rate. After soaking for 72 h, its corrosion rate decreased by 74.35% because of the depletion of hydrogen ions and the accumulation of corrosion products. The corrosion products were mainly Al2O3 and aluminum oxalate.

In situ detection of spatial distribution information of temperature-pH-strain of sandstone cultural relics

To monitor in situ the temperature, pH, and micro-strain change information of sandstone artifacts in the process of oxalic acid corrosion, the temperature, pH, and micro-strain fiber Bragg grating (FBG) sensors are developed. A theoretical model of the sensors is established. The surface morphology, material composition, pore structure, temperature, pH, and micro-strain of sandstone corroded by oxalic acid solutions of different concentrations are investigated. The experimental results show that the higher the concentration of oxalic acid, the stronger the corrosiveness of the sandstone. Ferrous oxalate and calcium oxalate produced by corrosion continuously precipitate from the inside of the rock, and the dual reaction of crystallization and dissolution occurs, reducing the proportion of fine pores in the rock pore suction and gravity. The oxalic acid solution is transported to the middle of the sandstone (3 cm) and undergoes the strongest chemical reaction with ore particles and debris, resulting in the maximum wavelength drift of the temperature, pH, and micro-strain sensors. The results of this study provide important support for analyzing the acid dissolution mechanism of stone cultural relics and the preventive protection of cultural relics.

Antibacterial Synergy Detection of Lignin Extract from Oil Palm Empty Fruit Bunches (Opefb) Combined with Amoxicillin Against Staphylococcus Aureus Using The Azdast Method

Oil palm empty fruit bunches (OPEFB) are waste generated by the palm oil industry and are generally considered an environmental problem due to their large quantity and difficult recyclability. This study's objective was to examine the potential of OPEFB lignin extract combined with amoxicillin in inhibiting the growth of Staphylococcus aureus bacteria. The Synergism Test of the OPEFB lignin extract-antibiotic combination was conducted using the AZDAST method (Ameri Ziaei Double Antibiotic Synergism Test). The lignin extraction process was a steam process using a 4% oxalic acid solution under optimal conditions. Then, Calcium ions precipitate 4% oxalate by adding Ca(OH)2 to the extract. The Lignin content was determined by UV-Vis spectrophotometry at 280 nm, and then the lignin extract was combined with antibiotics for antibacterial assay. The results showed a lignin content of 1.06 %. The AZDAST test results revealed clear zones from the combination of OPEFB lignin extract and amoxicillin with a diameter of 20.23 mm for the extract containing oxalate and 15.83 mm for the oxalate-free extract. Meanwhile, on average, the clear zone of single amoxicillin was only 14.13 mm. Based on these results, the combination of OPEFB lignin extract with amoxicillin was stronger than amoxicillin alone in inhibiting the growth of S. aureus, but it was not significantly different (p-value> 0.05). In conclusion, the potential of OPEFB lignin extract synergistically worked with the antibiotic amoxicillin in inhibiting the growth of S. aureus.

Bifunctional phosphorus-doped NiMo oxide/Ni–Fe hydroxide composite for overall water electrolysis: optimized performance with exceptional stability

The achievement of outstanding catalytic activity in water electrolysis is contingent upon the presence of abundant active sites with enhanced kinetics in electrocatalysts. This study focuses on enhancing the catalytic activity of water electrolysis under alkaline conditions by designing P-doped NiMo oxide/Ni–Fe hydroxide composite on Ni foam through a straightforward hydrothermal process. The composite is further annealed with NaH2PO4 and subjected to induced growth via in situ precipitation in an oxalic acid solution containing Fe precursors. The resulting bifunctional catalysts exhibit notable catalytic performance, manifesting overpotentials of 20.5 mV and 69.4 mV for the hydrogen evolution reaction (HER) and 225.9 mV and 271.8 mV for the oxygen evolution reaction (OER) to drive 10 and 100 mA/cm2, respectively. The improved kinetics, attributed to P doping, play a pivotal role in reducing the overpotential of HER. Meanwhile, the homogeneous mixing of Ni and Fe, coupled with the large active surface area, enhances the catalytic performance of OER. The investigation of Mo precursors reveals their significant contribution to structurally shaping the catalysts, thereby influencing excellent OER performance. Collectively, these factors enable overall water electrolysis with low potentials of 1.82 V at 100 mA/cm2, underscoring the efficacy of the developed bifunctional catalysts.