• Korean Journal of Food Science and Technology
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• v.17 no.2
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• pp.128-130
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• 1985

Solutions of 4.8 and 12% oxalic and 85% phosphoric acid were used for degumming of crude rice bran oil. 96.6% of total phosphatides was removed by degumming with either 2ml of 85% phosphoric acid or 20ml of 4% oxalic acid when added to 1kg of crude rice bran oil. Yields after degumming with oxalic and phosphoric acids were 63.6% and 61.0%, respectively.

• Applied Science and Convergence Technology
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• v.25 no.1
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• pp.15-18
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• 2016

Study investigated the optimal anodizing conditions for fabricating an oxide film that produces less contamination in a corrosive plasma environment, using oxalic acid and tartaric acid. Oxide films were produced using sulfuric acid, oxalic acid, and tartaric acid electrolyte mixtures with various mole ratios. The oxide film made by adding 0.05M tartaric acid to 0.3M oxalic acid showed higher breakdown voltage and lower leakage current. Additionally, contamination particles were reduced during plasma etching, thus demonstrates that this mixture presented optimal conditions. However, higher tartaric acid content (0.1 M, 0.15 M) led to lower breakdown voltages and higher leakage currents. Also, it resulted in more cracking during thermal shock tests as well as the generation of more contamination particles during plasma processing.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.401-401
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• 2011

In this work, we deposited Al2O3doped ZnO (AZO) thin films by direct current (DC) magnetron sputtering method with a $40^{\circ}$ tilted target, for application in the front layer of thin film solar cell. Wet chemical etching behavior of AZO films was also investigated. In order to optimize textured AZO films, oxalic acid ($C_2H_2O_4$)has been used as wet etchant of AZO film. In this experiment we used 0.001% concentration of oxalic acid various etching time, that showed an anisotropy in etching texture of AZO films. Electrical resistivity, Hall mobility and carrier concentration measurements are performed by using the Hall measurement, that are $6{\times}10^{-4}{\Omega}cm$, $20{\sim}25cm^2/V-s$ and $4{\sim}6{\times}10^{20}$, respectively.

• The Microorganisms and Industry
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• v.26 no.1
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• pp.18-30
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• 2000

Three kinds of organic matter such as glucose, oxalic acid, and ethanol were added to the media(N-free or NO$\_$3/-riched) and their effects on the nitrogen fixation of Nostoc pruniforme were measured by manometric technique through the experiments in vivo. 1) The organic matters used in this experiments showed effective results as a role of substrate for the fixation of atmospheric nitrogen. 2) In the nitrogen-free medium treated with the both of flucose nad ethanol, the highest nitrogen uptakes were detected in the treated of low concentrations (glucose ; 0.1%, 0.5%, ethanol : 0.1%, 0.5%). On the contrary, the highest nitrogen uptakes in NO$\_$3/-riched medium were measured at the treated of high concentrations (glucose ; 2%, 1%, ethanol ; 1.5%, 1.0%). 3) The highest nitrogen uptakes in N-free medium treated with oxalic acid were measured at the concentration of 2% and 1%, respectively. In the medium of NO$\_$3/-riched, the nitrogen uptakes were in the opposite directions.

• Mycobiology
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• v.44 no.4
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• pp.338-342
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• 2016

The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion HP-20 column chromatography, and the insoluble active compound was not adsorbed on the resin. Further fractionation by high-performance liquid chromatography (HPLC) suggested that the active compounds were organic acids. Nine organic acids were detected in the culture filtrate of L. edodes; oxalic acid was the major component and exhibited antibacterial activity against nine different phytopathogenic bacteria. Quantitative analysis by HPLC revealed that the content of oxalic acid was higher in the water extract from spent mushroom substrate than in liquid culture. This suggests that the water extract of spent L. edodes substrate is an eco-friendly control agent for plant diseases.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.87-98
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• 2018

The production of IPA from the oxidation of MX is completed under the catalysis of $H_3PW_{12}O_{40}$ (HPW) loaded on carbon and cobalt. Oxalic acid is tried to modify the carbon to upgrade the catalytic activity of HPW@C catalyst. The experiments show that the best carbon is acquired by carbonizing the carbon at $450^{\circ}C$ for 2 h in $N_2$ after being soaked in a $0.20mol\;l^{-1}$ oxalic acid solution for 16 h. The IPA produced by the HPW@C catalysts prepared with the carbon modified is 58.9% over that obtained by the catalysts prepared with the original carbon.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.446-452
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• 2019

We have developed a method that can leach Co, Mn, and Ni in the cathode active material safely using lactic acid. When cathode active material was leached by lactic acid, lactic acid showed the highest efficiency at 2 N than 1 N and above 4 N concentration. When the cathode active material was added incrementally into the solution of lactic acid, the maximum solubility was 30 g/L at 2 N concentration. Oxalic acid was added in the solution of lactic acid and it showed that rare metals represent the most economical recovery efficiency at 4 g/L. Based on this study, it was found that the optimal condition for recovery of rare metals from cathode active material is oxalic acid : cathode active material = 7 : 1 as a ratio of weight. In addition, it was observed that the precipitate produced by oxalic acid is a polynuclear crystalline material bonded with 3 components of Co, Ni, and Mn.

• Resources Recycling
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• v.28 no.6
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• pp.36-45
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• 2019

The spent petroleum catalysts contain rare metals such as vanadium, nickel, molybdenum, and cobalt. Therefore, the leaching of these rare metals from spent petroleum catalysts by organic acid was investigated in the present study. The leaching efficiency of metals by organic acid was in the following order: oxalic acid > tartaric acid > citric acid > maleic acid > ascorbic acid. Among the organic acids employed in this work, oxalic acid can be considered to be superior to the other acids in terms of metals leaching efficiency. The effect of several leaching conditions such as temperature, acid concentration, pulp density, stirring speed, and reaction time on the leaching of metals was investigated. Vanadium and molybdenum were selectively dissolved by oxalic acid from the spent catalysts. The leaching kinetics of vanadium by oxalic acid was also investigated. An activation energy of 8.76 kJ/mol indicated that the leaching kinetics of vanadium by oxalic acid solution was controlled by mass transfer.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.76-85
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• 2015

In this study, we investigated optimal reaction conditions for furfural production from lignocellulosic biomass by two-stage acid treatment. Furfural produced by this method was recovered using XAD-4 resin. Oxalic and sulfuric acid were used as catalysts for the first stage of treatment. The concentration of xylose in the hydrolysate obtained from the first stage was $18.86g/{\ell}$ with oxalic acid and $19.35g/{\ell}$ with sulfuric acid. The concentration of oligosaccharide was relatively high when sulfuric acid was used. Maximum yield of furfural, that is, 55.10% ($6.71g/{\ell}$), was obtained when oxalic acid was used for the first stage and $0.1m{\ell}$ of sulfuric acid was used for the second stage of treatment for 90 min. Furfural production yield increased with increasing the reaction time. Most of the furfural produced by this two-stage treatment method was recovered using XAD-4 resin.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.27-40
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• 1998

The solubility characteristics of organic compounds were studied in terms of the extraction efficiency as a function of the polarity of the organic solvent, and the acidity of water in urban aerosol samples collected in University of East Anglia (UEA), Norwich, England. The extraction efficiency of organic compounds were evaluated with respect to the organic carbon, -nitrogen and -hydrogen by means of a wide range of solvent which include polar and nonpolar organic solvents as well as acids and alkaline water. In addition, after being dissolved in aqueous solution, the aqueous chemistry of organic compounds were studied in terms of the organic metal complexes in aerosol, which were studied with oxalic acid, copper, and zinc. The results of this study indicate that solubility characteristics of organic compounds depend on the polarity of the solvents and the acidity of the solvents. In particular, some organic compounds are water soluble, even though they are much smaller than acetone soluble fractions. In the comparison between polar organic solvent extraction and non- polar organic solvent extraction, it can be thought that significant fraction of organic compounds analysed in the aerosol samples, are polar organic compounds because of the higher extraction efficiencies of organic compounds in polar organic solvent extraction than in nonpolar organic solvent extraction. Regarding the study of the oxalic -metal complexes, it can be thought that most oxalic acids are present in the form of oxalic -copper complexes in the aerosols collected at UEA.