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Journal of Energy Chemistry 2019年第6期28卷 1-8页

作者： Fengli Yang Jia Ren Qianqian Liu Lu Zhang Yuanyuan Chai Wei-Lin Dai Department of Chemistry & Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan University

The laminated porous N-deficient g-C3N4(CN–H)is successfully synthesized by a facile two-step hydrothermal calcination method using oxalic acid-assisted melamine as the *** with pristine g-C3N4(224μmol g-1h-1),the CN–H shows superior photocatalytic hydrogen production activity(up to 728μmol g-1h-1),which is three times higher than the unmodified *** draw out the multifaceted influences of oxalic acid modification on the visible-light-induced photocatalytic activity,various techniques are utilized to investigate the formation mechanism,structural characteristics and photoelectrical properties of CN–*** results indicate that the addition of a trace amount of oxalic acid to the precursor melamine results in a g-C3N4 structure possessing the advantage of both nitrogen defects and laminated *** properties can enlarge specific surface areas of g-C3N4,enhance an efficient separating of photogenerated electron-hole pairs and extend the range of spectral response,all contributing to the enhancement of the visible-light-induced photocatalytic activity.

关键词： oxalic acid Melamine Laminated porous N-deficient g-C3N4 Visible-light-induced photocatalytic activity for H2 generation

Explaining surface interactions for common associated gangues of rare earth minerals in response to the oxalic acid

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International Journal of Mining Science and Technology 2018年第2期28卷 343-346页

作者： Saeed Chehreh Chelgani Brian Hart Department of Electrical Engineering and Computer Science University of Michigan Surface Science Western University of Western Ontario

In the flotation of rare earth minerals(REMs), oxalic acid is reportedly acting both as a depressant and p H modifier. Although results of testing have established the significance of oxalic acid in the flotation process, its specific role in either the recovery or selectivity of REMs over their common gangue minerals is not well understood. Pulp p H reduction trials with alternative acids have not shown the same effect on the REMs recovery or the depression of gangue phases. This work studies the effect of oxalic acid on the surface of common REMs gangue minerals(quartz and carbonates(dolomite and calcite)) in a series of conditioning tests. Gangue surface analyses by time of flight secondary ion mass spectroscopy(TOFSIMS) indicate that oxalic acid inhibits the transfer of secondary ions generated during the conditioning process from one mineral to another. In this regard, the oxalate anion acts to fix ions in solution through chelation, limiting their participation in surface adsorption.

关键词： oxalic acid Rare earth Silicate Carbonate TOF-SIMS

Band gap tuning of g-C3N4via decoration with AgCl to expedite the photocatalytic degradation and mineralization of oxalic acid

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Journal of Environmental Sciences 2019年第10期31卷 1-12页

作者： Hanlu Shi Rui He Lei Sun Gang Cao Xiangjuan Yuan Dongsheng Xia School of Environmental Engineering Wuhan Textile University Wuhan 430073 China Engineering Research Center for Clean Production of Textile Dyeing and Printing Ministry of Education Wuhan 430073 China

A series of functional organic-metal AgCl-decorated graphitic carbon nitride(AgCl-CNx)composites were synthesized and applied for the degradation of oxalic acid(OA)under visible *** highest photocatalytic activity was achieved with AgCl decoration ratio of1.0(denoted as AgCl-CN1.0).The pseudo-first-order constant for OA degradation was 0.0722min-1 with the mineralization efficiency of 90.80%after 60 min reaction in the photocatalytic process with AgCl-CN1.0.A variety of characterization techniques including BrunauerEmmett-Teller,X-ray diffraction,scanning electron microscope,transmission electron microscopy,X-ray photoelectron spectroscopy,Fourier transform infrared spectra,ultraviolet-visible diffuse reflectance spectra,photoluminescence,and Mott-Schottky were utilized to elucidate the physicochemical,microstructure,and optical properties contributing to the improvement of the photocatalytic *** results showed that AgClCN1.0had an oblate flaky erythrocyte-like structure with a moderate band gap energy of^3.00 *** addition,the effects of the key parameters(i.e.,AgCl-CN1.0 dosage,initial OA concentration,solution pH,and presence of natural organic matter)on OA degradation were systematically *** scavenger experiments indicated that photogenerated holes,electrons,superoxide anion radicals,and hydroxyl radicals were the dominant reactive ***,AgCl-CN1.0 exhibited excellent stability and reusability for OA degradation without detectable Ag+release in the solution over multiple reaction *** efficient OA mineralization could be mainly ascribed to the moderate specific surface area,increased numbers of active sites,and effective interfacial charge transfer of ***,the AgCl-CN1.0 composite was demonstrated to be a highly efficient,stable,and recoverable photocatalyst.

关键词： AgCl Graphitic carbon nitride Photocatalytic degradation oxalic acid Mechanism

Synthesis and photochromic properties of WO_3 powder induced by oxalic acid

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Science China Chemistry 2009年第5期52卷 609-614页

作者： SHEN Yi1, ZHU Hua1, HUANG Rong1, ZHAO Li2 & YAN ShaNing1 1 Faculty of Material Science and Chemical Engineering, China University of Geosciences, Wuhan 430074, China 2 Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062, China 1. Faculty of Material Science and Chemical Engineering China University of Geosciences Wuhan 430074 China 2. Faculty of Materials Science and Engineering Hubei University Wuhan 430062 China

Tungsten trioxide powder with the novel morphology was prepared via the hydrothermal method with oxalic acid as the organic inducer, the structure and shape of which were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET. Furthermore, photochromic properties of the as-prepared powder samples were tested by an ultraviolet-visible spectrophotometer combined with a color difference meter. The corresponding results indicated that the induced product was still hexagonal WO3, made up of regularly spindle particles with 200-300 nm in length and 30-50 nm in width. The ratio of the length and width was from 4 to 10. Moreover, the special morphology improved its absorptive capacity to the excitation light source, resulting in its high photochromic properties.

关键词： WO3 powder photochromism oxalic acid organic inducer

Pre-harvest spraying of oxalic acid improves postharvest quality associated with increase in ascorbic acid and regulation of ethanol fermentation in kiwifruit cv. Bruno during storage

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Journal of Integrative Agriculture 2019年第11期18卷 2514-2520页

作者： Maratab Ali LIU Meng-meng WANG Zhen-e LI Sheng-e JIANG Tian-jia ZHENG Xiao-lin College of Food Science and Biotechnology Zhejiang Gongshang University

The kiwifruit trees(Actinidia deliciosa ***)were sprayed with 5 mmol L-1 oxalic acid(OA)or water(as control)at 130,137 or 144 d after full-blossom,and then the fruit were harvested at commercial maturity and stored at room temperature(20±1)℃ for 13 *** effect of pre-harvest spraying of OA on postharvest quality of kiwifruit was evaluated during *** OA spraying slowed the increase in soluble solids content(SSC)and decrease in titratable acid(TA),as well as increased contents of ascorbic acid(AsA)and total-AsA accompanied with higher AsA/DHA ratio in kiwifruit during ***,the OA spraying significantly reduced the contents of acetaldehyde and ethanol in kiwifruit,along with significant decrease in activities of enzymes involved in ethanol fermentation metabolism during the later period of storage,which was beneficial to control off-flavor associated with over accumulation of ethanol during *** was suggested that pre-harvest spraying of OA might maintain the postharvest quality of kiwifruit in relation to delay in fruit ripening,AsA maintenance and regulation of ethanol fermentation.

关键词： ethanol metabolism kiwifruit oxalic acid pre-harvest spraying postharvest quality

Quasi-Spherical Brookite TiO_2 Nanostructures Synthesized Using Solvothermal Method in the Presence of oxalic Acid

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Transactions of Tianjin University 2018年第4期24卷 326-339页

作者： Yifei Wang Yunling Zou Qianqian Shang Xin Tan Tao Yu Xianshou Huang Wenxin Shi Yao Xie Gao Yan Xiaoyi Wang School of Environmental Science and Engineering Tianjin University Tianjin Metro Group Co. Ltd. College of Science Civil Aviation University of China School of Chemical Engineering and Technology Tianjin University School of Science Tibet University

Brookite TiO_2,the latest TiO_2 photocatalyst,promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study,pure-phase brookite TiO_2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate(Ti(OC_4H_9)_4,TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods,such as X-ray diff raction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),transmission electron microscopy(TEM),Brunauer–Emmett–Teller(BET) measurements and ultraviolet–visible diff use spectroscopy(UV–Vis). Photocatalytic activities of the as-synthesized brookite TiO_2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO_2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity,and the corresponding degradation rate of methylene blue(10 mg/L) reached 96.7% after 90 min of illumination. In addition,the formation mechanism of pure-phase brookite TiO_2 was investigated. It was found that the formation of pure-phase brookite TiO_2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.

关键词： TiO 2 Brookite oxalic acid Photocatalytic properties

Optimization of Ilmenite Dissolution by Synergistic Effect of oxalic Acid and Hydrochloric Acid for Preparing Synthetic Rutile

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International Journal of Nonferrous Metallurgy 2018年第3期7卷 25-38页

作者： Mohammad Hasan Omidi Omid Salmani Nuri Hassan Tavakoli Department of Chemistry Faculty of Science University of Guilan Guilan Iran Department of Mining and Metallurgical Engineering Amirkabir University of Technology Tehran Iran Department of Physics and Chemistry Faculty of Basic Sciences Imam Ali University Tehran Iran

This study was carried out to investigate the interaction of oxalic acid with hydrochloric acid to attain the better performance for iron dissolution in comparison to absence of oxalic acid. The effects of oxalic acid on ratio of hydrochloric acid, acid concentration, ratio of liquid to solid, temperature and dissolution time are investigated for the dissolution of Fe and Ti from ilmenite to produce synthetic rutile. The DX7 software basing on an experimental design method with the central composite of response surface design is applied to specify the effects of the parameters and to optimize the leaching process. The optimum condition was determined by analysis of variance (ANOVA), indicating that the ratio of oxalic acid to hydrochloric acid for Fe dissolution and acid concentration for Ti dissolution were the most effective parameters. The results showed that the dissolution of Fe and Ti in 30% (w/w) hydrochloric acid solution was only 48.65% and 5.14%, respectively, while at the same condition and in the presence of oxalic acid with twice the ratio, these values are increased to 78.65% and 12.06%, respectively. The optimum values of parameters were as follows: oxalic acid to hydrochloric acid ratio (2:1), acid concentration (30%), ratio of liquid to solid (10), temperature (160 °C), and dissolution time (3 h). By applying the optimized parameters, Fe and Ti dissolution of 97.15% and 2.8% were predicted by the software with a desirability of 0.745. The results of leaching tests indicated that the Fe and Ti dissolution of 97.58% and 2.43%, were achieved, respectively, which are very close to the predicted value.

关键词： Ilmenite oxalic Acid Hydrochloric Acid Synthetic Rutile Leaching

Dahua Starts up oxalic Acid Unit

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China Chemical Reporter 2010年第10期21卷 22-22页

Danhua Chemical Technology Co Ltd (Danhua,SH:600844) announced its 100 000 t/a oxalic acid productionline came on stream on May 3rd at the site inTongliao,Inner Mongolia of northern *** line isaffiliated to the 200 000 t/a coal to monoethylene glycolunit that started up in December *** combined production of oxalic acid andmonoethylene glycol is aimed to improve the company’sproduct layout and enhance ability to earn *** is mainly used in processing rare earth *** claimed its coal to monoethylene glycol unitis China’s *** company is also a leading producerof acetic anhydride.

关键词： claimed glycol anhydride profit acetic oxalic layo

Humic and oxalic Acid Stimulates Grain Yield and Induces Accumulation of Plastidial Carbohydrate Metabolism Enzymes in Wheat Grown under Sandy Soil Conditions

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Agricultural Sciences 2015年第1期6卷 175-185页

作者： Hattem M. El-Shabrawi Bakry Ahmed Bakry Mohamed A. Ahmed Mohamed Abou-El-Lail Field Crops Research Department National Research Centre Cairo Egypt Plant Biotechnology Department National Research Centre Cairo Egypt Genetics Department Faculty of Agriculture and Natural Resources Aswan University Aswan Egypt

Humic and oxalic acids have the effects of promoting plant growth. We test whether they are able to positively impact wheat yield under newly reclaimed sandy soil, where water deficiency negatively influences yield. Foliar application of humic acid and oxalic acid on two wheat cultivars, Gemiza-9 and Sakha-93, leads to overall better performance of the plants and increases the yield significantly, irrespective of the cultivar genetic background. However, Gemiza-9 surpassed Sak- ha-93 in grain yield parameters. The highest values of grain and protein yields/ha were obtained in both cultivars, when the plants were sprayed with a combination of 17 mg/L humic acid and (300 mg/L) oxalic acid. Humic and oxalic acid showed accumulative yield-promoting effect. To understand the mechanism by which humic and oxalic acids promoted grain yield, we performed SDS-PAGE followed by MS-MS-LC analyses. We identified a unique humic acid-induced 52 KDa band in Gemiza-9. The band contained three major proteins, Ribulose bisphosphate carboxylase large chain, ADP-glucose synthase and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN). Thus humic acid increased the activity of plastid enzymes involved in photosynthesis, sucrose biosynthesis and starched accumulation to improve the overall performance of the plant.

关键词： Wheat Humic and oxalic Acids Carbohydrate Metabolism Calvin Cycle SDS-PAGE Mass Spectrum Analysis

Spectral Evidence for the One-Step Three-Electron Oxidation of Phenylsufinylacetic Acid and oxalic Acid by Cr(VI)

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American Journal of Analytical Chemistry 2013年第10期4卷 20-29页

作者： Perumal Subramaniam Natesan Thamil Selvi Department of Chemistry Govindammal Aditanar College for Women Tiruchendur India Research Department of Chemistry Aditanar College of Arts and Science Tiruchendur India

The co-oxidation of a mixture of phenylsulfinylacetic acid (PSAA) and oxalic acid (OxH2) by Cr(VI) in 20% acetonitrile-80% water (v/v) medium follows third order kinetics, first order, each with respect to PSAA, OxH2 and Cr(VI). The reaction involves nucleophilic attack of sulfur atom of PSAA on chromium of the oxidizing species, Cr(VI)-OxH2 to form a ternary complex, Cr(VI)-OxH2-PSAA followed by a one-step three-electron reduction of Cr(VI) to Cr(III) and simultaneous oxidation of both the substrates. The reaction is catalysed by Mn2+ ion while retarded by Al3+ ion. Electron releasing substituents in the meta- and para-positions of the phenyl ring of PSAA enhance the rate of co-oxidation while electron withdrawing substituents retards the reaction. The Hammett plots at different temperatures exhibit excellent correlation with negative ρ values. The reaction series obey isokinetic relationship and the observed isokinetic temperature is lying below the experimental range of temperature.

关键词： Phenylsulfinylacetic Acid oxalic Acid Co-Oxidation Nucleophilic Attack of Sulfur Three-Electron Transfer Substituent Effect