scholarly journals Electrochemical Studies of Lead Telluride Behavior in Acidic Nitrate Solutions

2015 ◽  
Vol 60 (1) ◽  
pp. 95-100
Author(s):  
E. Rudnik ◽  
P. Biskup
Keyword(s):  
Cyclic Voltammetry ◽  
Nitric Acid ◽  
Anodic Dissolution ◽  
Lead Telluride ◽  
Electrochemical Studies ◽  
Acid Solutions ◽  
Nitric Acid Solutions ◽  
Stationary Electrode ◽  
Acidic Electrolyte ◽  
Nitrate Solutions

Abstract Electrochemistry of lead telluride stationary electrode was studied in nitric acid solutions of pH 1.5-3.0. E-pH diagram for Pb-Te-H2O system was calculated. Results of cyclic voltammetry of Pb, Te and PbTe were discussed in correlation with thermodynamic predictions. Anodic dissolution of PbTe electrode at potential approx. -100÷50 mV (SCE) resulted in tellurium formation, while above 300 mV TeO2 was mainly produced. The latter could dissolve to HTeO+2 under acidic electrolyte, but it was inhibited by increased pH of the bath.

Cyclic Voltammetric Studies of Tellurium in Diluted HNO3 Solutions

2011 ◽  
Vol 56 (2) ◽  
pp. 270-277 ◽  
Author(s):  
E. Rudnik ◽  
J. Sobesto
Keyword(s):  
Nitric Acid ◽  
Cathodic Polarization ◽  
Acid Solutions ◽  
Cyclic Voltammetric ◽  
Nitric Acid Solutions ◽  
Stationary Electrode ◽  
Voltammetric Studies ◽  
Acidic Electrolyte ◽  
Cyclic Voltammetric Studies

Cyclic Voltammetric Studies of Tellurium in Diluted HNO3SolutionsElectrochemistry of tellurium stationary electrode was studied in nitric acid solutions of pH 2.0 and 2.5. Two sparingly soluble products were formed at potentials above 200 mV (SCE): TeO2and H2TeO3. H2TeO3and TeO2could dissolve to HTeO+2under acidic electrolyte, but this process was hindered at pH 2.5. Cathodic polarization of tellurium electrode below -800 mV was accompanied by evolution of H2Te, which was then oxidized at the potentials approx. -700 mV.

scholarly journals BISMUTH (III) OXALATES OBTANING BY PRECIPITATION FROM NITRIC ACID SOLUTIONS

2017 ◽  
Vol 60 (3) ◽  
pp. 55
Author(s):  
Evgeniya V. Timakova ◽  
Lubov I. Afonina ◽  
Natalya V. Bulina ◽  
Svetlana St. Shatskaya ◽  
Yuri M. Yukhin
Keyword(s):  
Nitric Acid ◽  
Mixing Time ◽  
Molar Ratio ◽  
Acid Solutions ◽  
X Ray Diffraction ◽  
Fine Grained ◽  
Nitric Acid Solutions ◽  
Wide Range ◽  
Degree Of Purification ◽  
Nitrate Solutions

This paper describes the precipitation of bismuth (III) oxalates from industrial nitric acid solutions. The process was carried out by adding of oxalic acid depending on the molar ratio of oxalate ions to bismuth (n), reaction temperature and the acidity of solution. The existence of four different crystal structures in the precipitation products was confirmed by the methods of X-ray diffraction, IR spectroscopy in combination with chemical analysis of solid phases. The compound with composition Bi(C2O4)OH is precipitated from nitric acid solutions in a wide range of temperatures at n = 1. Increasing n to 1.5 at room temperature leads to the formation of compound Bi2(C2O4)3∙7H2O. The precipitation of octahydrate bismuth oxalate Bi2(C2O4)3∙8H2O occurs when n = 2, process temperature of 80 °C and mixing time of 1 h. Further increasing in mixing time leads to recrystallization with formation of hexahydrate having the composition Bi2(C2O4)3∙6H2O. Latter compound can also be obtained by increasing n to 4. The degree of purification from impurity of metals such as Pb, Ag, Zn, Cu, Fe and the morphology of the bismuth (III) oxalates were also determined. The maximum degree of the removal of the impurities is shown to achieved by the precipitation of Bi2(C2O4)3∙8H2O as the desired product from industrial bismuth nitrate solutions. Bismuth oxalates with compositions Bi(C2O4)OH and Bi2(C2O4)3∙7H2O are the fine-grained powders, which could be used as precursors for the synthesis of the bismuth oxide materials.Forcitation:Timakova E.V., Afonina L.I., Bulina N.V., Shatskaya S.S., Yukhin Yu.M. Bismuth (III) oxalates obtaning by precipitation from nitric acid solutions. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 55-60.

scholarly journals Neptunium extraction by N,N-dialkylamides

2020 ◽  
Vol 108 (9) ◽  
pp. 707-716
Author(s):  
Jarrod M. Gogolski ◽  
Peter R. Zalupski ◽  
Travis S. Grimes ◽  
Mark P. Jensen
Keyword(s):  
Nitric Acid ◽  
Solvent Extraction ◽  
Radioactive Waste ◽  
Partial Oxidation ◽  
Acid Solutions ◽  
Nitric Acid Solutions ◽  
Organic Solutions

AbstractSeparation of neptunium by solvent extraction has been based on tributylphosphate (TBP) for decades, but TBP is not fully incinerable, which adds to the burden of long-lived radioactive waste. Alternatives to TBP for uranium and plutonium extraction, such as the N,N-diakylamides, previously have been explored in the hopes of transitioning to an extractant that is incinerable. Four N,N-diakylamides, N,N-dihexylhexanamide (DHHA), N,N-dihexyloctanamide (DHOA), N,N-di(2-ethylhexyl)butanamide (DEHBA), and N,N-di(2-ethylhexyl)-iso-butanamide (DEHiBA) were considered in this work for their potential to extract millimolar concentrations of Np(IV), Np(V), and Np(VI) from nitric acid solutions into organic solutions containing 1 M extractant in Exxsol D60. Under these conditions the branching of the alkyl substituents affects the extractability of Np(VI) and Np(IV), causing three of the dialkylamides, DHHA, DHOA and DEHBA, to extract neptunium in the expected order Np(VI) > Np(IV) > > Np(V). In contrast, branched DEHiBA is so poor an extractant for Np(IV) that the extraction order becomes Np(VI) > > Np(V) > Np(IV) between 0.1 and 5.6 M HNO3 due to partial oxidation of the Np(V) in nitric acid.

Extraction of tetra- and hexavalent actinide ions from nitric acid solutions using some diglycolamide functionalized calix[4]arenes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajesh B. Gujar ◽  
Parveen K. Verma ◽  
Prasanta K. Mohapatra ◽  
Mudassir Iqbal ◽  
Jurriaan Huskens ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Solvent Extraction ◽  
Extraction Efficiency ◽  
Minor Actinide ◽  
Acid Solutions ◽  
Extraction Mechanism ◽  
Nitrate Ion ◽  
Nitric Acid Solutions ◽  
Actinide Ions ◽  
Acid Extractant

Abstract Neptunium is one of the most important minor actinide elements with some of its isotopes having very long half-lives, therefore necessitating its separation from acidic radioactive wastes. Solvent extraction of Np4+ and NpO2 2+ was studied using three multiple diglycolamide (DGA) extractants with n-propyl, n-octyl and 3-pentyl substituents termed as L I , L II and L III , respectively, in a mixed diluent of 5% isodecanol and 95% n-dodecane. For comparison purpose, the extraction of Pu4+ and UO2 2+ was carried out under identical conditions. The extraction efficiency of the ligands for the tetravalent ions followed the trend: L II  > L I  > L III , which changed to L III  > L II  > L I for the hexavalent ions. While the extraction of the tetravalent ions was reasonably good (ca. 90–98%) with an extremely low (5.0 × 10−5 M) ligand concentration, poor extraction (ca. 5–16%) of the hexavalent ions was seen even with a 20 times higher concentration of the ligand. In general, Pu4+ was better extracted than Np4+, while NpO2 2+ was marginally better extracted then UO2 2+. A ‘solvation’ type extraction mechanism was proposed based on the extraction profiles obtained as a function of the concentrations of the feed nitric acid, extractant as well as nitrate ion. The extracted species were found out to be M(NO3)4·mL and MO2(NO3)2·nL (M = Np or Pu, 1 < m < 2, n ≃ 1).

Separation of Americium and Curium in Nitric Acid Solutions via Oxidation of Am(III) by Bismuthate and Perxenate Ions

2020 ◽  
Vol 62 (5) ◽  
pp. 581-586
Author(s):  
Yu. M. Kulyako ◽  
D. A. Malikov ◽  
T. I. Trofimov ◽  
S. A. Perevalov ◽  
K. S. Pilyushenko ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Acid Solutions ◽  
Nitric Acid Solutions
Sign in / Sign up

Export Citation Format

Share Document