Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 27 for “"Chromium(VI)"”.
-
Studies of Chromium(vi) Reactions With Sulfur-Containing Compounds
… 6d0f6098cfce9c78f01f0b9ee9ef9b6e (MD5) Previous issue date: 1971
-
Studies on the biotransformation of chromium (VI) by methane oxidising bacteria.
… containing organic or inorganic contaminants. Cr(VI), the highest oxidation state of the metal chromium, is widely used in various industries, and is extremely toxic to animals and humans. Utilisation of chromium (Cr) reducing microbes and their products can enhance the efficiency of the process …
-
Electrochemical Reduction Products of Chromium(vi) in Molten Lithium-Chloride - Potassium-Chloride Eutectic
… e197f6bff1acb828c65aa7928bccef6f (MD5) Previous issue date: 1968
-
The kinetics of the Arsenic(III)-Chromium(VI) reaction in various buffer solutions
The oxidation of arsenic(III) by chromium(VI) requires the postulation of uncommon oxidation states as reactive intermediates. The possible intermediates of chromium are the divalent, tetravalent, and pentavalent states. Recently arsenic(IV) has been postulated as a reactive intermediate in certain …
-
The kinetics of the arsenic(III) - chromium(VI) reaction on acetic acid-acetate buffers
… study of the oxidation of arsenic(III) by chromium(VI) was made in acetic acid-acetate buffers at ionic strengths 1.5M and 3.0M. The reaction rate showed a first order dependence on the arsenic(III), total chromium(VI), and acetic acid concentrations. Two possible mechanisms for the …
-
Molecular mechanisms of the carcinogen chromium(VI)-induced DNA-protein crosslinking in cultured intact human cells
Chromium(VI)-induced DNA-protein crosslinking is implicated in chromium Carcinogenicity. However, the mechanism of chromate-induced DNA-protein crosslinking has not been established. Based on the current literature and our preliminary data, we hypothesized that Cr(VI)-induced DNA-protein crosslinks …
-
A kinetic study of the chromium (VI) - arsenic (III) reaction in pyridine-pyridinium buffer solutions containing oxalate
The oxidation of arsenic (III) by chromium (VI) has been studied in pyridine - pyridinium buffers with and without added oxalate ion. The rate law at pH 4.6 for the reactions without oxalate is best described as - d[Cr(VI)]/dt = (0.535 [As(III)]² [Cr(VI)])/(1+187 [As(III)]) This is in accord with …
-
Preparation and characterisation of poly (vinyl alcohol)/chitosan/silicon dioxide (PVA/CS/SiO2) beads for the chromium (VI) (Cr(VI) removal
Chromium pollution has become a global issue and many techniques have been developed for the removal of Chromium (VI) (Cr(VI)) from wastewater. In this study, blend polymer absorbent beads which was poly (vinyl alcohol)/chitosan/silicon dioxide (PVA/CS/SiO2) beads were prepared by dropwise method …
-
Environmental fate and effects of chromium(III) and (IV) investigated using electroanalytical chemistry.
… , during the electrochemical determination of chromium(III) or (VI) was developed. This media exchange system was used to investigate the effect of pH on the complexation and pre-concentration of chromium separately from the production of the electrochemical signal. While the complexation and …
-
Differences of DNA-Transcription Factor Interactions Following Chromium Exposure
… active proteins. It is known that reduction of chromium(VI) to chromium(III) creates species such as chromium(V) and chromium(IV) which interact with and damage DNA. An oxidative event, such a chromium(VI) reduction to chromium(III) could allow a crosslinking of protein-bound DNA. Redox values …
-
Differences of DNA-Transcription Factor Interactions Following Chromium Exposure
… active proteins. It is known that reduction of chromium(VI) to chromium(III) creates species such as chromium(V) and chromium(IV) which interact with and damage DNA. An oxidative event, such a chromium(VI) reduction to chromium(III) could allow a crosslinking of protein-bound DNA. Redox values …
-
Modeling of Parallel Plate Electrochemical Reactors and Liquid Tin Anode Solid Oxide Fuel Cells
… is presented for the reduction of hexavalent chromium in a parallel plate electrochemical reactor via a homogenous reaction between chromium (VI) and iron (II) generated at the iron anode. The effects of the space velocity of the feed solution, the concentration of supporting electrolyte, the …
-
Bioremediation of hexavalent chromium using gram-negative bacteria.
Hexavalent chromium (Cr (VI)), the most toxic form of chromium, is widely used in industrial processes. As a result substantial amounts of Cr (VI) contaminated wastes are produced. The use of microbial cells as bioremediation of heavy metals is a potential alternative to conventional chemical …
-
Determination of chromium in natural waters by flow injection inductively coupled plasma emission spectrometry.
… approach for the accurate determination of chromium species in river waters is developed in this thesis. This is based on the use of alumina micro columns for in situ sampling and storage, followed by a simple introduction of the in situ samples to an inductively coupled plasma emission …
-
Immobilisation of copper, chromium and arsenic on stabilised domestic refuse
The disposal of copper-chromium-arsenic, whether in solution or in combination with wood, has the potential to become a global problem. This chemical is commonly called CCA or Tanalith, and is classed as a waterborne wood preservative. Current global production of this class of chemicals is …
-
Vanadium uptake and transport in higher plants
… by a post uptake treatment in a solution of chromium(VI). This removal of extracellular vanadium by chromium was considered to be a genuine exchange process although the mechanism involved is unclear. The effect of temperature, pH, metabolic inhibitors and complexing agents were also examined …
-
Synthesis and characterisation of silica adsorption platforms for use in environmental remediation
… removal times (15 min) compared to the previously published methods that take approximately 10 h. This material was functionalised with an amine-based functional group to study the feasibility of separation of chromium (III) and chromium (VI) from aqueous solution. A maximum adsorption …
-
The application of iron oxide based photocatalysts in chromium photoredox chemistry
Chromium(VI) is a reactive and highly toxic pollutant species which is present in certain industrial effluent streams as well as sea water and polluted ground water. Chromium(III), however, is relatively inert and less toxic. Conventional methods used to eliminate Cr(VI) from aqueous phase include …
-
Nanoscale Enhancement of Photosensitized Radionuclide Stimulated Therapy
<p>Photodynamic therapy (PDT) provides efficient tumor killing through the generation of reactive oxygen species (ROS) from the optical excitation of a photosensitizer (PS). Furthermore, this mechanism is highly immune stimulating, providing systemic tumor immunity with a reduction in metastasis. …
-
Microbial CR(VI) reduction in indigenous culture of bacteria: characterization and modelling
South Africa currently faces multiple Cr(VI) contamination problems which are unsuccessfully remediated using available technologies. Cr(VI) is highly toxic, carcinogenic and mutagenic in nature and it is exclusively released through anthropogenic activities. A new treatment approach is proposed …
Page 1 of 2