RECOVERY OF GERMANIUM BY PRECIPITATION FROM STRONGLY ALKALINE SOLUTION

2020 ◽  
Author(s):  
Andrzej Piotrowicz ◽  
Stanisław Pietrzyk ◽  
Artur Puchała
Keyword(s):  
Alkaline Solution ◽  
Precipitation Process ◽  
Research Material ◽  
Low Concentrations ◽  
Industrial Material ◽  
Industrial Solution ◽  
Wide Ph Range ◽  
Synthetic Solution ◽  
Ph Range

The research material was a strongly alkaline solution containing germanium, lead, arsenic, zinc and trace amounts of other metals, obtained by leaching of industrial material. The aim of the study was to determine the behavior of the above metals in the precipitation process using various acidic agents: HCl, H2SO4, C2H2O4, C6H8O7. The tests were carried out in a wide pH range. The behavior and role of individual ions during the acidification of germanate solution is poorly understood, hence the study of this subject was undertaken. The resulting precipitates and solutions were examined by XRF, XRD and ICP techniques. The recovery yields of individual elements was determined. Attempts were also made to precipitate Ge from a synthetic solution in order to compare the results obtained for the solution of an industrial solution. This research shows that the presence of other ions interferes with the selective recovery of Ge from research solutions. Generally, it can be said that the method of recovery by acidification is effective at low concentrations of the solution's components.

Role of Persistent Vascular Renin after Bilateral Nephrectomy in Goldblatt-Two Kidney Hypertension

1978 ◽  
Vol 55 (s4) ◽  
pp. 23s-26s ◽  
Author(s):  
H. Thurston ◽  
B. C. Hurst ◽  
R. F. Bing ◽  
J. D. Swales
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Bilateral Nephrectomy ◽  
Salt Loading ◽  
Angiotensin System ◽  
Wide Ph Range ◽  
Salt Depletion ◽  
Ph Range ◽  
Aortic Homogenate

1. Aortic homogenate contains renin-like activity which on incubation generates angiotensin I over a wide pH range. 2. Rat aortic renin measured at an incubation pH of 6·5 rose and fell in parallel to plasma renin with salt depletion and salt-loading respectively. Renin measured at an incubation pH of 5·3 showed little relationship with plasma renin. 3. Aortic renin (pH 6·5) was elevated in Goldblatt-two kidney hypertension and slowly fell for 24 h after bilateral nephrectomy whereas the fall in plasma renin was complete by the first hour. Aortic renin (pH 5·3) was also high, but did not fall after bilateral nephrectomy. 4. Aortic renin (pH 6·5) is probably derived from plasma renin whereas renin measured at pH 5·3 is probably a tissue renin. 5. The prolonged half-life of aortic renin (pH 6·5) explains the observation that the renin—angiotensin system appears to be active in maintaining blood pressure for several hours after bilateral nephrectomy whereas the decline in plasma renin is rapid and does not continue significantly beyond 1 h.

A structural perspective on lactoferrin function1This article is part of a Special Issue entitled Lactoferrin and has undergone the Journal's usual peer review process.

2012 ◽  
Vol 90 (3) ◽  
pp. 320-328 ◽  
Author(s):  
Heather M. Baker ◽  
Edward N. Baker
Keyword(s):  
Peer Review Process ◽  
Iron Binding ◽  
Multifunctional Protein ◽  
Wide Ph Range ◽  
Iron Binding Protein ◽  
Productive Research ◽  
Ph Range ◽  
The Many ◽  
And Function

The 3-D structure of human lactoferrin was first solved in atomic detail in 1987. Since that time, a variety of proven and postulated activities have been added to the original annotation of lactoferrin as an iron-binding protein. Structural studies have also expanded to include iron-bound and iron-free (apo) forms, mutants, and the lactoferrins of different species. In this review, we take the current information on both structure and function and show that the 3-D structure provides a useful framework for understanding some activities and also points to productive research directions that could help elucidate other reported functions. Some functions relate to iron binding where the role of lactoferrin is to scavenge and retain iron across a wide pH range. We specifically focus on functions that depend on the surface structure of the molecule, identifying features that may determine the many other protective properties of this multifunctional protein.

Synthesis of supported vertical NiS2 nanosheets for hydrogen evolution reaction in acidic and alkaline solution

RSC Advances ◽  
2015 ◽  
Vol 5 (42) ◽  
pp. 32976-32982 ◽  
Author(s):  
Xiaolin Wu ◽  
Bin Yang ◽  
Zhongjian Li ◽  
Lecheng Lei ◽  
Xingwang Zhang
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Alkaline Solution ◽  
Graphite Substrate ◽  
Excellent Activity ◽  
Wide Ph Range ◽  
Ph Range

We report a two-step synthesis to grow vertical NiS2 nanosheets on a graphite substrate, the NiS2 electrocatalyst showed excellent activity toward hydrogen evolution reaction in a wide pH range.

scholarly journals Molecular Dynamics Simulation of Cetyl Phosphate Adsorption in Flotation of Magnesite and Pertinent Chemical Aspects

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 761 ◽  
Author(s):  
Yuan Tang ◽  
Jin Yao ◽  
Wanzhong Yin ◽  
Sadan Kelebek
Keyword(s):  
Molecular Dynamics ◽  
Value Added ◽  
Md Simulations ◽  
Ion Concentration ◽  
Dynamics Simulation ◽  
Phosphate Adsorption ◽  
Chemical Equilibria ◽  
Low Concentrations ◽  
Ph Range

Magnesite ores are important resources in the production of value-added magnesium materials. Generally, low selectivity of conventional collectors and the requirement of a large amount of depressant has been a motivation for researchers to identify alternate collectors. In this work, the role of potassium cetyl phosphate (PCP) as a new collector in magnesite flotation is investigated using molecular dynamics (MD) simulations and chemical equilibria, electrokinetics and wettability. The results indicate that PCP exhibits a strong collecting ability for magnesite particles even with low concentrations. The presence of PCP leads to significant alterations in the electric double layer and contact angle behavior of magnesite, which results in rapid adsorption of PCP on magnesite surface. The results from chemical computations show that the monoanionic forms of PCP are the dominant species in the weakly acidic pH range, where monohydroxy magnesium species and the ion concentration of magnesite in suspension can be controlled by adjusting pH. The adsorption models indicate that the stable adsorption of PCP on magnesite surfaces occurs spontaneously, supporting the potentiality for selective magnesite flotation in its separation from other carbonate minerals.

Some Observations on the Saponin Accumulation in Oat Seedlings and on the Transformation of the Avenacosides to the Antibiotic 26-Desgluco-avenacosides

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1095-1099 ◽  
Author(s):  
Ute Laudenbach ◽  
Jürgen Kesselmeier
Keyword(s):  
Protective Device ◽  
Steroidal Saponins ◽  
Temperature Optimum ◽  
Plastid Development ◽  
Drastic Decrease ◽  
Etiolated Seedlings ◽  
Wide Ph Range ◽  
Ph Range ◽  
Distinct Temperature

Abstract The accumulation of the steroidal saponins avenacoside A and B in oat was investigated in green and etiolated seedlings and was found to be strictly bound to the growth of the seedlings. No significant differences were detected between green and etiolated seedlings, showing that there is no relation between saponin accumulation and plastid development. As the role of the oat saponins has to be seen as a protective device against fungi and bacteria, the transformation of the inactive avenacosides to their corresponding antibiotic 26-desgluco-avenacosides was tested in dependence of pH and temperature. During disruption of leaves, transformation occurs almost completely over a wide pH-range (pH 4 -pH 10); the degree of transformation exhibits no distinct temperature optimum but a drastic decrease at 70 °C.

Testosterone Potentiation of Ionophore and ADP Induced Platelet Aggregation : Relationship to Arachidonic Acid Metabolism

1981 ◽  
Vol 46 (02) ◽  
pp. 538-542 ◽  
Author(s):  
R Pilo ◽  
D Aharony ◽  
A Raz
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Unsaturated Fatty Acids ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Arachidonic Acid Metabolism ◽  
Ionophore A23187 ◽  
Low Concentrations ◽  
Induced Aggregation

SummaryThe role of arachidonic acid oxygenated products in human platelet aggregation induced by the ionophore A23187 was investigated. The ionophore produced an increased release of both saturated and unsaturated fatty acids and a concomitant increased formation of TxA2 and other arachidonate products. TxA2 (and possibly other cyclo oxygenase products) appears to have a significant role in ionophore-induced aggregation only when low concentrations (<1 μM) of the ionophore are employed.Testosterone added to rat or human platelet-rich plasma (PRP) was shown previously to potentiate platelet aggregation induced by ADP, adrenaline, collagen and arachidonic acid (1, 2). We show that testosterone also potentiates ionophore induced aggregation in washed platelets and in PRP. This potentiation was dose and time dependent and resulted from increased lipolysis and concomitant generation of TxA2 and other prostaglandin products. The testosterone potentiating effect was abolished by preincubation of the platelets with indomethacin.

The Role of Evaluative Tools in the Creation of the Memorial Media Portrait of Jacques Chirac (1932—2019)

2020 ◽  
pp. 97-110
Author(s):  
E. N. Mikhailova ◽  
V. A. Telegina
Keyword(s):  
Print Media ◽  
Political Elite ◽  
Systematic Analysis ◽  
Research Material ◽  
Political Orientations ◽  
Different Types ◽  
The Media ◽  
The Creation ◽  
Entire Text

The article is devoted to the study of evaluative tools used in modern French media in order to form the media image of a representative of the political elite. The techniques used in the creation of a memorial media portrait of Jacques Chirac (1932—2019), President of France from 1995 to 2007 are considered. The research material was the most prestigious French print media of various political orientations, published in late September — early October 2019 in connection with the death of the ex-President of the French Republic. The relevance of the research topic is dictated by the close attention of modern linguistics to axiological phenomena, differently presented in different types of discursive practices. The novelty of the study is due to the appeal to the analysis of the complex of evaluation tools used in the French print media when characterizing the former leader of the state during the nation’s farewell period. The estimated potential of the title of the article and its influence on the formation of the estimated vector of the entire text of the publication are shown. A systematic analysis of the assessment expression means, reflected in the memorial media portrait of the politician, is given. The factors that influenced the peculiarities of their use in this type of media portrait are revealed.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

Sign in / Sign up

Export Citation Format

Share Document