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Coordination-reduction leaching process of ion-adsorption type rare earth ore with ascorbic acid

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Journal of Rare Earths 2023年第8期41卷 1225-1233,I0004页

作者： Jinfa Chen Jiang Qiu Li Huang Xin Chen Ying Yang Yanfei Xiao Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Ganzhou Engineering Technology Research Center of Green Metallurgy and Process Intensification Ganzhou 341000China Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural ResourcesGanzhou 341000China Key Laboratory of Testing and Tracing of Rare Earth Products for State Market Regulation Ganzhou 341000China

The magnesium sulfate(MgSO_(4))-ascorbic acid(Vc)compound leaching technique can extract rare earth elements(REEs)existing in ion-exchangeable phase and colloidal phase from ion-adso rption type rare earth ore through the synergy effect of coordination and reduction,but its reaction process and mechanism remain *** this paper,the coordination-reduction leaching mechanism was analyzed from the perspectives of leaching thermodynamics and kinetics,which provide theoretical guidance for the compound leaching *** the case of neodymium,about 45%of dissolved neodymium will exist as the complex species of NdVc_(()3(aq))in Nd-Vc-sulfate *** on this,it is deduced that the Gibbs free energy of the leaching reaction of ion-exchangeable phase REEs will change to a more negative value through the coordination of REEs cations and Vc anions in the MgSO_(4)leaching *** addition,the E_(h)-pH diagrams of Ce-SO_(4)^(2-)-H_(2)O and Fe-SO_(4)^(2-)-H_(2)O together with the dissolution experiments confirm that the added Vc initiates the leaching process of colloidal phase REEs through reduction-dissolution *** the study of leaching kinetics,the leaching of REEs is controlled by diffusion and chemical reaction in the co mpound leaching system since colloidal phase REEs are ***,the addition of Vc can shift the leaching equilibrium to a more favorable state and accelerate leaching *** rare earth leaching efficiency of ion-exchangeable phase and colloidal phase can be effectively improved by increasing the reaction temperature,the conce ntrations of leaching agent and Vc,and the leaching agent acidity.

关键词： Ion-adsorption type rare earth ore ascorbic acid Coordination Reduction Leaching Mechanism

Multifunctional N,S-doped and methionine functionalized carbon dots for on−off−on Fe^(3+)and ascorbic acid sensing,cell imaging,and fluorescent ink applying

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Nano Research 2023年第4期16卷 5401-5411页

作者： Zheng Yang Tiantian Xu Shaobing Zhang Hui Li Yali Ji Xiaodan Jia Jianli Li Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education College of Chemistry&Materials ScienceNorthwest UniversityXi’an 710127China College of Chemistry and Chemical Engineering Xi’an University of Science and TechnologyXi’an 710054China Key Laboratory of Coal Resources Exploration and Comprehensive Utilization Ministry of Land and ResourcesXi’an 710012China

Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in considering of the attractive optical *** this work,we present a CDs based fluorescent sensor from polyvinylpyrrolidone,citric acid,and methionine as precursors by hydrothermal *** selective quantifying of Fe^(3+)and ascorbic acid(AA)are based on the fluorescent on-off-on process,in which the fluorescent quenching is induced by the coordination of the Fe^(3+)on the surface of the CDs,while the fluorescence recovery is mainly attributed to redox reaction between Fe^(3+)and AA,breaking the coordination and bringing the fluorescence *** by the good water solubility and biocompatibility,significant photostability,superior photobleaching resistance as well as high selectivity,sensitivity,and interference immunity,which are constructed mainly from the N,S-doping and methionine surface functionalization,the CDs have not only been employed as fluorescence ink in multiple anticounterfeiting printing and confidential document writing or transmitting,but also been developed as promising fluorescence sensors in solution and solid by CDs doped test strips and hydrogels for effectively monitoring and removing of Fe^(3+)and AA in environmental aqueous *** CDs have been also implemented as effective diagnostic candidates for imaging and tracking of Fe^(3+)and AA in living cells,accelerating the understanding of their function and importance in related biological processes for the prevention and treatment specific diseases.

关键词： carbon dots fluorescent sensors Fe^(3+) ascorbic acid fluorescent ink message encryption

Enhanced debromination of 2,2’,4,4’-tetrabromodiphenyl ether(BDE-47)by zero-valent zinc with ascorbic acid

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Frontiers of Environmental Science & Engineering 2020年第3期14卷 127-139页

作者： Chaojin Jiang Xiaoqian Jiang Lixun Zhang Yuntao Guan Guangdong Provincial Engineering Technology Research Center for Urban Water Cycle and Water Environment Safety Tsinghua Shenzhen International Graduate SchoolShenzhen 518055China State Environmental Protection Key Laboratory of Microorganism Application and Risk Control School of EnvironmentTsinghua UniversityBeijing 100084China

A new technique of zero-valent zinc coupled with ascorbic acid(ZVZ/AA)was developed and applied to debrominate the 2,2,,4,4,-Tetrabromodiphenyl ether(BDE-47),which achieved high conversion and rapid debromination of BDE-47 to less-or non-toxic *** reaction conditions were optimized by the addition of 100 mg/L Z V Z particles and 3 mmol/L A A at original solution p H=4.00 using the solvent of methanol/H2O(v:v=4:6),which could convert approximately 94%of 5 mg/L BDE-47 into lower-brominated diphenyl ethers within a 90 min at the ZVZ/AA *** high debromination of BDE-47 was mainly attributed to the effect of A A that inhibits the formation of Zn(Ⅱ)(hydr)oxide passivation layers and promotes the corrosion of ZVZ,which leads to increase the reactivity of ***,ion chromatography and gas chromatography mass spectrometry analyses revealed that bromine ion and lower-debromination diphenyl ethers formed during the reduction of ***,based on the generation of the intermediates products,and its concentration changes over time,it was proposed that the dominant pathway for conversion of BDE-47 was sequential debromination and the final products were diphenyl *** results suggested that the ZVZ/AA system has the potential for highly efficient debromination of BDE-47 from wastewater.

关键词： 2,2,,4,4,-tetrabromodiphenyl ether(BDE-47) ascorbic acid Reductive debromination Zero-valent zinc

2D-titanium carbide(MXene)based selective electrochemical sensor for simultaneous detection of ascorbic acid,dopamine and uric acid

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Journal of Materials Science & Technology 2021年第13期72卷 122-131页

作者： Nagaraj Murugan Rajendran Jerome Murugan Preethika Anandhakumar Sundaramurthy Ashok K.Sundramoorthy Department of Chemistry SRM Institute of Science and TechnologyKattankulathur603203Tamil NaduIndia SRM Research Institute SRM Institute of Science and TechnologyKattankulathur603203Tamil NaduIndia

Two-dimensional(2 D)titanium carbide(MXene)nanosheets exhibited excellent conductivity,flexibility,high volumetric capacity,hydrophilic surface,thermal stability,***,it has been exploited in various ***,we report synthesis of mixed phase 2 D MXene as a catalytic material for simultaneous detection of important biomolecules such as ascorbic acid(AA),dopamine(DA)and uric acid(UA).Crystalline structure,surface morphology and elemental composition of mixed phase titanium carbide(Ti-C-T_(x))MXene(T_(x)=-F,-OH,or-O)nanosheets were confirmed by X-ray diffraction(XRD),Raman spectroscopy,high-resolution transmission electron microscopy(HR-TEM),high-re solution scanning electron microscopy(HR-SEM)and Energy-dispersive X-ray spectroscopy(EDS)mapping ***,Ti-C-T_(x) modified glassy carbon electrode(GCE)was prepared and its electrochemical properties are studied by cyclic voltammetry(CV)and diffe rential pulse voltammetry(DPV).It was found that Ti-C-T_(x) modified GCE(Ti-C-T_(x)/GCE)showed excellent electrocatalytic activity and separated oxidation peaks of important biomolecules such as AA(at 0.01 V),DA(at 0.21 V)and UA(at 0.33 V).Also,Ti-C-T_(x)/GCE sensor is enabled their simultaneous detection in physiological pH from 100 to 1000μM for AA,0.5-50μM for DA and 0.5-4μM&100-1500μM for *** limit of detection’s(LOD)was estimated as 4.6μM,0.06μM and 0.075μM for AA,DA and UA,***,real sample analysis indicated that spiked AA,DA and UA can be determined accurately by Ti-C-T_(x)/GCE with the recovery ratio in the range between 100.5%-103%in human urine *** proposed Ti-C-T_(x) modified electrode exhibited good stability,selectivity and reproducibility as an electrochemical sensor for the detection of AA,DA and UA molecules.

关键词： Titanium carbide Dopamine Uric acid ascorbic acid Electrochemical sensor

Recovery of rare earths from ion-absorbed rare earths ore with MgSO_4-ascorbic acid compound leaching agent

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Journal of Rare Earths 2018年第5期36卷 521-527页

作者： Fuguo Lai Li Huang Guohua Gao Run Yang Yanfei Xiao School of Metallurgical and Chemical Engineering Jiangxi University of science and Technology Ganzhou 341000 China Institute of Engineering ＆ Research Jiangxi University of Science and Technology Ganzhou 341000 China

The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable ***, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO4 and environmentally friendly leaching.

关键词： Rare earth Leaching MgSO4 ascorbic acid Ion-absorbed rare earths ore

Boosting SN38-based oral chemotherapy to combine reductionbioactivated structured lipid-mimetic prodrug with ascorbic acid

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Nano Research 2022年第10期15卷 9092-9104页

作者： Helin Wang Qi Lu Yifan Miao Jiaxuan Song Mingyang Zhang Zixuan Wang Haotian Zhang Zhonggui He Chutong Tian Jin Sun Department of Pharmaceutics Wuya College of InnovationShenyang Pharmaceutical UniversityShenyang 110016China School of Life Science and Biopharmaceutics Shenyang Pharmaceutical UniversityShenyang 110016China

The reduction-responsive disulfide bonds have been widely used as bioactive linkages to facilitate a rapid release of anticancer drugs into tumor ***,the activation can be hindered by the kinetics of the thiol-disulfide exchange *** with an additional reductant is a promising strategy to further boost drug ***,inspired by the specific absorption mechanism of triglyceride fat,structured lipid-mimetic oral prodrugs of 7-ethyl-10-hydroxycamptothecin(SN38)were designed to improve intestinal permeability and bypass the first-pass ***38 prodrugs were prepared into lipid formulations that could self-emulsify into nano-sized particles after entering the gastrointestinal ***,we found that the oral bioavailability of the prodrug lipid formulation could be up to 2.69-fold higher than that of the parent SN38,indicating an effective oral *** addition,the reduction-responsive disulfide bond was used as a linker,and ascorbic acid(ASC)was coadministrated to further promote the efficient release of SN38 from the *** enhanced the oral antitumor effect of the reduction-responsive oral prodrug and exhibited good *** summary,the combination of a structured lipid-mimetic prodrug and ASC was firstly demonstrated to boost the oral chemotherapy effect of the difficult-for-oral chemotherapeutics.

关键词： oral chemotherapy structured lipid-mimetic prodrug 7-ethyl-10-hydroxycamptothecin(SN38) ascorbic acid

Chromium-induced membrane damage: protective role of ascorbic acid

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Journal of Environmental Sciences 2001年第3期13卷 272-275页

作者： Sankar Kumar Dey Prasunpriya Nayak Somenath Roy Department of Human Physiology with Community Health Vidyasagar UniversityMidnapore 721102West BengalIndia

Importance of chromium as environmental toxicant is largely due to impact on the body to produce cellular toxicity. The impact of chromium and their supplementation with ascorbic acid was studied on plasma membrane of liver and kidney in male Wistar rats (80-100g body weight). It has been observed that the intoxication with chromium (i.p.) at the dose of 0.8 mg/100g body weight per day for a period of 28 days causes significant increase in the level of cholesterol and decrease in the level of phospholipid of both liver and kidney. The alkaline phosphatase, total ATPase and Na\++\|K\++\|ATPase activities were significantly decreased in both liver and kidney after chromium treatment, except total ATPase activity of kidney. It is suggested that chromium exposure at the present dose and duration induce for the alterations of structure and function of both liver and kidney plasma membrane. ascorbic acid (i.p. at the dose of 0.5 mg/100g body weight per day for period of 28 days) supplementation can reduce these structural changes in the plasma membrane of liver and kidney. But the functional changes can not be completely replenished by the ascorbic acid supplementation in response to chromium exposure. So it is also suggested that ascorbic acid (nutritional antioxidant) is useful free radical scavenger to restrain the chromium induced membrane damage.

关键词： chromium liver kidney membrane ascorbic acid

Ferric ion-ascorbic acid complex catalyzed calcium peroxide for organic wastewater treatment:Optimized by response surface method

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Chinese Chemical Letters 2021年第11期32卷 3387-3392页

作者： Deling Yuan Chen Zhang Shoufeng Tang Zetao Wang Qina Sun Xiaoyu Zhang Tifeng Jiao Qingrui Zhang Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse Hebei Key Laboratory of Applied ChemistrySchool of Environmental and Chemical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

Hydrogen peroxide(H_(2)O_(2))disproportionation,iron precipitation,and narrow pH range are the drawbacks of traditional Fenton *** surmount these barriers,we proposed a ferric ion(Fe^(3+))-ascorbic acid(AA)complex catalyzed calcium peroxide(CaO_(2))Fenton-like system to remove organic dyes in *** collaborative Fe^(3+)/AA/CaO_(2)system presented an obvious improvement in the methyl orange(MO)decolorization,and also effectively eliminated other *** surface method was employed to optimize the running parameters for this coupling *** the optimized arguments(2.76 mmol/L Fe^(3+),0.68 mmol/L AA,and 4 mmol/L CaO_(2)),the MO removal achieved 98.90%after 15 min at pH 6.50,which was close to the computed outcome of 99.30%.Furthermore,this Fenton-like system could perform well in a wide range of pH(3-11),and enhance the H_(2)O_(2)decomposition and Fe ions *** scavenger experiment result indicated that hydroxyl radical,superoxide anion free radical,and singlet oxygen were acted on the dye ***,electron spin resonance analysis corroborated that the existences of these active species in the Fe^(3+)/AA/CaO_(2)*** study could advance the development of Fenton-like technique in organic effluent disposal.

关键词： Ferric ion ascorbic acid Calcium peroxide Response surface method Dye removal

Overoxidized poly(3,4-ethylenedioxythiophene)-gold nanoparticles-graphene-modified electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid

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Journal of Pharmaceutical Analysis 2021年第6期11卷 699-708页

作者： Junqiang Pan Mei Liu Dandan Li Haonan Zheng Dongdong Zhang Department of Cardiovascular Medicine Xi'an Central HospitalXi'an710061China School of Pharmacy Xi'an Jiaotong University Health Science CenterXi'an710003China

An innovative,ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene)(OPEDOT),gold nanoparticles(Au NPs),and electrochemically reduced graphene oxide(ERGO)was prepared on a glassy carbon electrode(GCE)(OPEDOT-Au NPs-ERGO/GCE)through homogeneous chemical reactions and heterogeneous electrochemical *** morphology,composition,and structure of this nanocomposite were characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,and X-ray photoelectron *** electrochemical properties of the OPEDOT-Au NPs-ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(III)chloride redox probe *** modified electrode shows excellent electro-catalytic activity for dopamine(DA)and uric acid(UA)under physiological p H conditions,but inhibits the oxidation of ascorbic acid(AA).Linear voltammetric responses were obtained when DA concentrations of approximately 4.0-100μM and UA concentrations of approximately 20-100μM were *** detection limits(S/N=3)for DA and UA were 1.0 and 5.0μM,respectively,under physiological conditions and in the presence of 1.0 m M of *** developed method was applied to the simultaneous detection of DA and UA in human urine,where satisfactory recoveries from 96.7%to 105.0%were *** work demonstrates that the developed OPEDOT-Au NPs-ERGO ternary nanocomposite,with its excellent ion-selectivity and electro-catalytic activity,is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.

关键词： Graphene Poly(3,4-ethylenedioxythiophene) Overoxidation Dopamine Uric acid ascorbic acid