scholarly journals Hydrogen Peroxide Ammonium Citrate Extraction: Mineral Decomposition and Preliminary Waste Rock Characterization

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 706
Author(s):  
Teemu Karlsson ◽  
Marja Liisa Räisänen ◽  
Timo Myöhänen ◽  
Lena Alakangas ◽  
Marja Lehtonen ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Waste Rock ◽  
Ammonium Citrate ◽  
Specific Method ◽  
Element Mobility ◽  
X Ray ◽  
Increased Risk ◽  
High Metal ◽  
Rock Characterization ◽  
Ore Exploration

A commonly-used method in ore exploration is hydrogen peroxide ammonium citrate (HA) extraction, which has not typically been used in waste rock characterization. In this study, the sulfide specificity and leaching of other minerals in HA extraction was evaluated and its performance was compared with the aqua regia (AR) extraction for preliminary assessment of harmful element mobility. Samples collected from several different mine sites in Finland were utilized. The waste rock sample S contents ranged from 0.3% to 5.3%, and sums of the AR extractable elements As, Cd, Co, Cu, Ni and Zn range from 120 to 8040 mg/kg. The drainage types ranged from acid high-metal to neutral low-metal, with pH’s of 3.3–7.7. Mineralogical changes that took place in the HA solution were investigated by the field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive X-ray spectroscopy analyzer (EDS) and X-ray diffraction (XRD) methods. Results of the study showed that the HA extraction appears to be a more specific method for sulfide decomposition compared with AR extraction. Sulfide minerals, especially base metal sulfides pentlandite, chalcopyrite and sphalerite, decomposed efficiently in HA extraction. However, the Fe-sulfides pyrrhotite and pyrite only decomposed incompletely. The study showed that the HA extraction results can be used in the preliminary prediction of element mobility. Based on the results, the elevated As, Cd, Co, Cu, Ni, S and Zn leachability in the HA extraction appears to predict elevated drainage concentrations. If the HA-extractable sum of As, Cd, Co, Cu, Ni and Zn is >750 mg/kg, there is an increased risk of high-metal (>1000 µg/L) drainage. Therefore, the HA extraction data, e.g., produced during ore exploration, can be utilized to preliminary screen the risks of sulfide related element mobilities from waste rock material.

Heterogeneous Fenton Catalytic Removal of Organic Pollutant in Aqueous Solution by using Coal Gangue as a Catalyst

2019 ◽  
Vol 12 (4) ◽  
pp. 312-325
Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Removal Rate ◽  
Organic Pollutant ◽  
Coal Gangue ◽  
Ion Leakage ◽  
Heterogeneous Fenton ◽  
Solution Ph ◽  
X Ray

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.

Crystal and solution structure of (E)-1,2-bis(ethylsulphonyl)cyclobutane-1,2-dicarbonitrile

1989 ◽  
Vol 54 (12) ◽  
pp. 3253-3259
Author(s):  
Jaroslav Podlaha ◽  
Miloš Buděšínský ◽  
Jana Podlahová ◽  
Jindřich Hašek
Keyword(s):  
Hydrogen Peroxide ◽  
Solution Structure ◽  
Peroxide Oxidation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Study ◽  
Hydrogen Peroxide Oxidation ◽  
Unusual Product ◽  
C Nmr

The unusual product of the reaction of 2-chloroacrylonitrile with ethane thiol and following hydrogen peroxide oxidation was found to be (E)-1,2-bis(ethylsulphonyl)cyclobutane-1,2-dicarbonitrile by means of X-ray crystallography. 1H and 13C NMR study of this compound has proven the same conformation of the molecule in solution.

scholarly journals Multi-Energy X-Ray Computed Tomography for Source Rock Characterization

2021 ◽  
Vol 27 (S1) ◽  
pp. 1030-1031
Author(s):  
Airdias Korolkovas ◽  
Seongjin Yoon ◽  
Alexander Katsevich ◽  
Shannon Eichmann ◽  
Qiushi Sun ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Source Rock ◽  
X Ray ◽  
X Ray Computed ◽  
Rock Characterization

Degradation of Odontologic X-Ray Film Developing Wastewaters by Photo-Fenton Process

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Luciana Igarashi-Mafra ◽  
Edmilson César Bortoletto ◽  
Maria Angelica Simões Dornella Barros ◽  
Amanda Cristina Alfredo Contrucci Sorbo ◽  
Naiara Aguiar Galliani ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Total Phenol ◽  
Process Conditions ◽  
Phenol Removal ◽  
Total Phenols ◽  
Fenton Process ◽  
X Ray ◽  
Control Factors ◽  
Fenton Oxidation Process ◽  
Wastewater Samples

Effluents from radiographic X-ray film developing processes feature a high contaminant load (COD about 70000 mg/L and total phenols concentration about 16956 mg/L). Photo-Fenton's are potentially useful oxidation processes for destroying toxic organic compounds in water. In these reactions, hydrogen peroxide is combined with ferrous or ferric iron in the presence of light to generate hydroxyl radicals (·OH). The photo-Fenton process was explored as a photochemical treatment to degrade wastewater from radiographic X-ray film developing processes coming from odontologic clinics. A response surface methodology was applied to optimize the photo-Fenton oxidation process conditions using total phenol removal as the target parameter to be optimized, and the reagent concentrations, as related to the initial concentration of organic matter in the effluent, and time and pH as the control factors to be optimized. The best results in terms of maximal total phenol removal and economic process were achieved when wastewater samples were treated at pH 5 in the presence of hydrogen peroxide and iron in the ratios [total phenols]:[H2O2] 1:3 w/w and [Fe2+]:[H2O2] 1:18 w/w and time 1 h.

scholarly journals Crystallization and preliminary X-ray analysis of formate oxidase, an enzyme of the glucose–methanol–choline oxidoreductase family

2010 ◽  
Vol 66 (9) ◽  
pp. 1064-1066 ◽  
Author(s):  
Yoshifumi Maeda ◽  
Daiju Doubayashi ◽  
Takumi Ootake ◽  
Masaya Oki ◽  
Bunzo Mikami ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Single Crystal ◽  
Aspergillus Oryzae ◽  
Diffraction Data ◽  
Diffusion Method ◽  
Hanging Drop ◽  
Space Group ◽  
X Ray ◽  
Vapour Diffusion

Formate oxidase (FOD), which catalyzes the oxidation of formate to yield carbon dioxide and hydrogen peroxide, belongs to the glucose–methanol–choline oxidoreductase (GMCO) family. FOD fromAspergillus oryzaeRIB40, which has a modified FAD as a cofactor, was crystallized at 293 K by the hanging-drop vapour-diffusion method. The crystal was orthorhombic and belonged to space groupC2221. Diffraction data were collected from a single crystal to 2.4 Å resolution.

Discriminatory Aspects of Pre-employment Screening: Low-Back X-ray Examinations in the Railroad Industry

1979 ◽  
Vol 5 (3) ◽  
pp. 197-214
Author(s):  
Paul H. Rockey ◽  
Jane Fantel ◽  
Gilbert S. Omenn
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Screening Program ◽  
Job Applicants ◽  
Radiation Hazard ◽  
Low Back ◽  
Negative Consequences ◽  
X Ray ◽  
Work Related ◽  
Increased Risk

AbstractIn screening the majority of job applicants, most of this nation's railroads administer a low-back X-ray examination in an attempt to ascertain the likelihood that the applicant will sustain future work-related low-back pain or injury. Many applicants are rejected for employment on the basis of the X-ray findings. The railroads apparently perceive this screening program as a cost-effective means (1) of decreasing the incidence of compensation claims for work-related injuries, brought against the rail-roads under the Federal Employers' Liability Act (FELA), (2) of reducing the number of lost workdays resulting from low-back pain or injury, and (3) of protecting particularly susceptible workers from job-related hazards.The authors of this Article submit that low-back X-ray examinations are poor predictors of future low-back pain or injury. They assert that the railroads' use of such examinations misclassifies a substantial number of job applicants as being at increased risk for such pain or injury, and, in consequence, unfairly denies them employment. Furthermore, the authors claim, the screening program has other negative consequences. For example, applicants rejected for railroad employment on the basis of X-ray findings may as a result have difficulty finding jobs in other industries. In addition, they state, there is a potential radiation hazard to examinees. Moreover, both the railroads and those applicants accepted for employment may inappropriately be reassured by normal findings.On balance, the authors conclude, the screening program has a negative social value. The authors suggest that the program, in effect, erroneously labels many applicants as handicapped, and then denies them employment. Such persons might have legal recourse under federal and state statutes prohibiting employment discrimination against the handicapped.

Novel peroxosolvates of tetraalkylammonium halides: the first case of layers containing hydrogen-bonded peroxide molecules

CrystEngComm ◽  
2021 ◽  
Author(s):  
Mger A. Navasardyan ◽  
Stanislav Bezzubov ◽  
Alexander G. Medvedev ◽  
Petr V Prikhodchenko ◽  
Churakov Andrei
Keyword(s):  
Hydrogen Peroxide ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Case ◽  
Tetraalkylammonium Halides ◽  
Hydrogen Bonded

Novel peroxosolvates of tetraalkylammonium halides Et4N+Cl–•2(H2O2) (1), Et4N+Br–•2(H2O2) (2), Me3(ClCH2CH2)N+Cl–•H2O2 (3) and Me3PhN+Cl–•H2O2 (4) were prepared from concentrated hydrogen peroxide and the corresponding structures were determined by X-ray crystallography. Structures...

A Two-step Electrodeposition of Pd-Cu/Cu2O Nanocomposite on FTO Substrate for Non-enzymatic Hydrogen Peroxide Sensor

2021 ◽  
Vol 17 ◽  
Author(s):  
Ke Huan ◽  
Li Tang ◽  
Dongmei Deng ◽  
Huan Wang ◽  
Xiaojing Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Pd Nanoparticles ◽  
Optimal Conditions ◽  
Potential Oscillation ◽  
X Ray Diffraction ◽  
X Ray

Background: Hydrogen peroxide (H2O2) is a common reagent in the production and living, but excessive H2O2 may enhance the danger to the human body. Consequently, it is very important to develop economical, fast and accurate techniques for detecting H2O2. Methods: A simple two-step electrodeposition process was applied to synthesize Pd-Cu/Cu2O nanocomposite for non-enzymatic H2O2 sensor. Cu/Cu2O nanomaterial was firstly electrodeposited on FTO by potential oscillation technique, and then Pd nanoparticles were electrodeposited on Cu/Cu2O nanomaterial by cyclic voltammetry. The chemical structure, component, and morphology of the synthesized Pd-Cu/Cu2O nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties of Pd-Cu/Cu2O nanocomposite were studied by cyclic voltammetry and amperometry. Results: Under optimal conditions, the as-fabricated sensor displayed a broad linear range (5-4000 µM) and low detection limit (1.8 µM) for the determination of H2O2. The proposed sensor showed good selectivity and reproducibility. Meanwhile, the proposed sensor has been successfully applied to detect H2O2 in milk. Conclusion: The Pd-Cu/Cu2O/FTO biosensor exhibits excellent electrochemical activity for H2O2 reduction, which has great potential application in the field of food safety.

Sign in / Sign up

Export Citation Format

Share Document