scholarly journals Odstraňování rtuti z kyselých roztoků chloridu rtuťnatého sorbenty připravenými katalyzovanou vulkanizací rostlinných olejů

2022 ◽  
Vol 116 (1) ◽  
pp. 48-55
Author(s):  
Karel Svoboda ◽  
Tomáš Ružovič ◽  
Michael Pohořelý ◽  
Miloslav Hartman ◽  
Michal Šyc
Keyword(s):  
Flue Gas ◽  
Hot Water ◽  
Metallic Elements ◽  
Mercury Ions ◽  
Metallic Mercury ◽  
Acidic Solutions ◽  
Mercury Compounds ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Neutral Conditions

Mercury is a metallic element, dangerous and toxic for the environment. Presently, the incineration of municipal solid waste (MSW) belongs to important sources of Hg emissions. Methods of conversion of metallic mercury and mercury compounds from soluble and toxic forms into water insoluble/non-toxic form (HgS) are sought after. Gaseous HCl and a significant part of HgCl2 vapors present in flue gas from incineration of MSW can be removed there by absorption in hot water. Efficiencies of Hg2+ removal from acidic water solutions by means of sorbents prepared by catalyzed reaction of sulfur with vegetable oils (inverse vulcanization) were studied. These kinds of sorbents were tested and found to be exploitable for selective removal of mercury ions from aqueous solutions, particularly from acidic solutions containing HCl at higher temperatures (50–75 °C). Presence of relatively high concentrations of salts of some other metallic elements (Fe, Zn, Ca) had only very small effects on Hg-sorption. Mercury adsorbed on such sorbents converts relatively quickly into a non-toxic form (HgS). Reactive sulfides and SH‑groups present on the surface of the sorbent particles contribute to a faster sorption of mercury and its conversion to HgS. Leaching of zinc from the catalyst (Zn‑diethyldithiocarbamate) present in the vulcanized sorbents is negligible at neutral conditions and small (about 10 %) at acidic conditions (pH = 1.5).

ON THE MECHANISM OF THE DISSOLUTION OF MAGNESIUM IN ACIDIC SALT SOLUTIONS: I. PHYSICAL CONTROL BY SURFACE FILMS

1953 ◽  
Vol 31 (9) ◽  
pp. 849-867 ◽  
Author(s):  
E. J. Casey ◽  
R. E. Bergeron
Keyword(s):  
Ionic Strength ◽  
Chemical Control ◽  
Corrosion Potential ◽  
Surface Film ◽  
Surface Films ◽  
Salt Solutions ◽  
Acidic Solutions ◽  
Activity Temperature ◽  
Acidic Salt ◽  
High Concentrations

A kinetic study and analysis has been made of the effects of ionic strength, acid activity, temperature, and salt type on the dissolution of magnesium in acidic salt solutions. This is an example of the simplest type of corrosion involving hydrogen evolution. The results are interpreted in terms of the effects of the various factors on the structure of a surface film which must be magnesium oxide and/or hydroxide even in acidic solutions. The importance of internal dissolutions in the film at high concentrations of attacking reagent, for this and other cases, is shown. Owing to complex formation, under certain conditions an odd case of "chemical control" of the dissolution rate in this simplest case becomes evident. Corrosion potential measurements aid in the interpretation.

Hydrogen generation by both acidic and catalytic hydrolysis of sodium borohydride

2018 ◽  
Vol 5 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Olga V. Netskina ◽  
Tihon N. Filippov ◽  
Oksana V. Komova ◽  
Valentina I. Simagina
Keyword(s):  
Hydrogen Evolution ◽  
Sodium Borohydride ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
Catalytic Hydrolysis ◽  
Hydrogen Storage Materials ◽  
Acidic Solutions ◽  
High Concentrations ◽  
Sulfuric And Hydrochloric Acids ◽  
Hydrolysis Of

Abstract Sodium borohydride tablets have been employed as hydrogen-storage materials. Hydrogen release was performed by acidic hydrolysis where solutions of sulfuric and hydrochloric acids were added to the tablets, and by catalytic hydrolysis where water was added tablets of solid-state NaBH4/Co composite. In acidic solutions hydrogen evolution occurred instantaneously, and at high concentrations of acids the releasing hydrogen contained an admixture of diborane. Hydrogen evolution from the solidstate NaBH4/Co composite proceeded at a uniform rate of 13.8±0.1 cm3·min-1, water vapor being the only impurity in the evolving gas.

scholarly journals Amphiphilic Block Copolymers Bearing Hydrophobic γ-Tocopherol Groups with Labile Acetal Bond

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Shotaro Yukioka ◽  
Takuya Kitadume ◽  
Suchismita Chatterjee ◽  
Gan Ning ◽  
Tooru Ooya ◽  
...  
Keyword(s):  
Diblock Copolymer ◽  
Main Chain ◽  
Polymer Micelles ◽  
Poly Ethylene Glycol ◽  
The Core ◽  
Anticancer Effects ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Poly Ethylene ◽  
Hydrophobic Cores

High concentrations of γ-tocopherol (γTCP) tend to show antioxidant, anti-inflammatory, and anticancer effects. In this study, we prepared polymer micelles under acidic conditions with a controlled release of γTCP due to the decomposition of pendant acetal bonds. First, a precursor diblock copolymer composed of poly(ethylene glycol) (PEG) and acrylic acid (AA) was prepared. This was followed by the synthesis of an amphiphilic diblock copolymer (PEG54-P(AA/VE6/γTCP29)140), incorporated into hydrophobic γTCP pendant groups attached to the main chain through an acetal bond. The prepared PEG54-P(AA/VE6/γTCP29)140 was further dispersed in water to form polymer micelles composed of hydrophobic cores that were generated from a hydrophobic block containing γTCPs and hydrophilic shells on the surface. Under acidic conditions, γTCP was then released from the core of the polymer micelles due to the decomposition of the pendant acetal bonds. In addition, polymer micelles swelled under acidic conditions due to hydration of the core.

scholarly journals Probing the Molecular Interactions of Chitosan Films in Acidic Solutions with Different Salt Ions

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1052
Author(s):  
Qiyan Tan ◽  
Yajing Kan ◽  
Huixiang Huang ◽  
Weiping Wu ◽  
Xinjian Lu
Keyword(s):  
Molecular Interactions ◽  
Contact Time ◽  
Surface Forces Apparatus ◽  
Acidic Solutions ◽  
Interaction Mechanisms ◽  
Salt Ions ◽  
Bridge Model ◽  
Wide Range ◽  
Acidic Conditions ◽  
Chitosan Films

Understanding the interaction mechanisms of chitosan films plays a central role in a wide range of its applications, such as bioadhesive, drug delivery, wound healing, tissue engineering, and wastewater treatment for heavy metal ions. Here, we investigated the molecular interactions between chitosan films in acidic solutions with different salt ions using a surface forces apparatus (SFA). The results showed that chitosan can be adsorbed to mica surfaces by electrostatic interaction under acidic conditions. The force measurements demonstrated that the interactions depend on the salt types, concentrations, and contact time. With the addition of 1 mM LaCl3 and NaCl into the acetic acid (HAc) buffer solution, the cohesion between chitosan films enhanced by about 45% and 20%, respectively, after a contact time of 60 min. The enhanced cohesion induced by the combination of partly intermolecular complexation formation in a bridge model and conformation adjustment of chitosan under contact time in 1 mM LaCl3 solution. However, the cohesion reduced rapidly and even disappeared when the salt concentration increased to 10 mM and 100 mM. We proposed that the cross-linked structures of chitosan mainly contribute to the significant reduction of chitosan cohesion in LaCl3 solution. In comparison, the decrease in cohesion capacity in NaCl solution mainly results from the enhanced hydration effect. Our findings may provide insights into the interaction mechanisms of chitosan films under nanoconfinement in acidic conditions and suggestions for the development of chitosan-based materials.

scholarly journals Preparation of Isotopically Labelled Standards of Creatinine Via H/D Exchange and Their Application in Quantitative Analysis by LC-MS

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1514
Author(s):  
Remigiusz Bąchor ◽  
Andrzej Konieczny ◽  
Zbigniew Szewczuk
Keyword(s):  
Internal Standard ◽  
Test Method ◽  
Simple Test ◽  
Liquid Chromatography Mass Spectrometry ◽  
Creatinine Concentration ◽  
Back Exchange ◽  
Acidic Conditions ◽  
Facile Preparation ◽  
The Stability ◽  
Neutral Conditions

Kidneys play a crucial role in maintaining metabolic homeostasis in a body. Serum creatinine concentration is a simple test used as an indicator of renal function. One of the known ways of quantifying creatinine concentration is the liquid chromatography-mass spectrometry (LC-MS) method, using an isotopically labeled analog of creatinine as an internal standard. Unfortunately, such isotope-labeled analogs are expensive and their synthesis is complex. Here we demonstrate a facile preparation of deuterated analogues of creatinine, via the H/D exchange of hydrogens located at the α-carbon (α-C) of the N-methylated amino acid part, under basic conditions. The stability of retrieved isotopologues was analyzed under both neutral or acidic conditions, and the results revealed that the introduced deuterons do not undergo back-exchange. In addition, the coelution of deuterated and non-deuterated forms under acidic and neutral conditions was observed. The prepared isotopologues were successfully applied in the quantitative LC-MS analysis of urine samples, and the results demonstrated that the presented strategy is novel and inexpensive, and that the quantification correlates with the commonly used Jaffe test method.

scholarly journals A New Fungal Isolate, Penidiella sp. Strain T9, Accumulates the Rare Earth Element Dysprosium

2015 ◽  
Vol 81 (9) ◽  
pp. 3062-3068 ◽  
Author(s):  
Takumi Horiike ◽  
Mitsuo Yamashita
Keyword(s):  
Rare Earth ◽  
Mine Drainage ◽  
Liquid Waste ◽  
Morphological Characterization ◽  
Rrna Gene ◽  
Content Type ◽  
Cell Pellet ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Rrna Gene Sequencing

ABSTRACTWith an aim to develop a highly efficient method for the recovery of rare earth elements (REEs) by using microorganisms, we attempted to isolate dysprosium (Dy)-accumulating microorganisms that grow under acidic conditions from environmental samples containing high concentrations of heavy metals. One acidophilic strain, T9, which was isolated from an abandoned mine, decreased the concentration of Dy in medium that contained 100 mg/liter Dy to 53 mg/liter Dy after 3 days of cultivation at pH 2.5. The Dy content in the cell pellet of the T9 strain was 910 μg/mg of dry cells. The T9 strain also accumulated other REEs. Based on the results of 28S-D1/D2 rRNA gene sequencing and morphological characterization, we designated this fungal strainPenidiellasp. T9. Bioaccumulation of Dy was observed on the cell surface of the T9 strain by elemental mapping using scanning electron microscopy-energy dispersive X-ray spectroscopy. Our results indicate thatPenidiellasp. T9 has the potential to recover REEs such as Dy from mine drainage and industrial liquid waste under acidic conditions.

RESISTIVITY, SELF‐POTENTIAL, AND INDUCED‐POLARIZATION SURVEYS OF A VAPOR‐DOMINATED GEOTHERMAL SYSTEM

Geophysics ◽  
1973 ◽  
Vol 38 (6) ◽  
pp. 1130-1144 ◽  
Author(s):  
A. A. R. Zohdy ◽  
L. A. Anderson ◽  
L. J. P. Muffler
Keyword(s):  
Geothermal Field ◽  
Induced Polarization ◽  
Hot Water ◽  
Thermal Waters ◽  
Geothermal System ◽  
Electrical Soundings ◽  
Lateral Extent ◽  
High Concentrations ◽  
Lake Deposits ◽  
Self Potential

The Mud Volcano area in Yellowstone National Park provides an example of a vapor‐dominated geothermal system. A test well drilled to a depth of about 347 ft penetrated the vapor‐dominated reservoir at a depth of less than 300 ft. Subsequently, 16 vertical electrical soundings (VES) of the Schlumberger type were made along a 3.7‐mile traverse to evaluate the electrical resistivity distribution within this geothermal field. Interpretation of the VES curves by computer modeling indicates that the vapor‐dominated layer has a resistivity of about 75–130 ohm‐m and that its lateral extent is about 1 mile. It is characteristically overlain by a low‐resistivity layer of about 2–6.5 ohm‐m, and it is laterally confined by a layer of about 30 ohm‐m. This 30‐ohm‐m layer, which probably represents hot water circulating in low‐porosity rocks, also underlies most of the survey at an average depth of about 1000 ft. Horizontal resistivity profiles, measured with two electrode spacings of an AMN array, qualitatively corroborate the sounding interpretation. The profiling data delineate the southeast boundary of the geothermal field as a distinct transition from low to high apparent resistivities. The northwest boundary is less distinctly defined because of the presence of thick lake deposits of low resistivities. A broad positive self‐potential anomaly is observed over the geothermal field, and it is interpretable in terms of the circulation of the thermal waters. Induced‐polarization anomalies were obtained at the northwest boundary and near the southeast boundary of the vapor‐dominated field. These anomalies probably are caused by relatively high concentrations of pyrite.

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