Water Purification Oxidation
Mostrando 1-12 de 16 artigos, teses e dissertações.
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1. Purificação e caracterização de nanotubos de carbono produzidos pelo método de descarga em arco elétrico
The objective of this work was to study the purification of a sample of commercial carbon nanotubes (CNTs) produced by the Carbolex arc-discharge method using the catalyst mixture Ni/Y (4/1 at. %). Another objective of this work was to investigate an alternative functionalization route for the introduction of hydroxyl groups (-OH) onto CNT sidewalls and to e
Publicado em: 2008
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2. Estudos de formação e remoção de subprodutos de desinfecção (SPDS) em aguas contendo acidos humicols quando sumetidas a dioxido de cloro / Studies of formation and remotion of disinfection by products (DBP), generated by the oxidation of solutions containing humic substances throught the use of chlorine dioxide
The objective of the present research was to analyze the formation of disinfection by products (DPB), generated by the oxidation of solutions containing humic substances with the addition of bromide ions through the use of chlorine dioxide, isolated or associated with free chlorine in different concentrations and reaction times. The technique of gaseous chro
Publicado em: 2007
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3. Trihalomethane formation and remotion in pre-oxidation water treatment processes using chlorine / Formação e remoção de trihalometanos em aguas de abastecimento tratadas, na pre-oxidação, com cloro livre
The present research evaluated, in laboratory scale, the formation of trihalomethanes (THM) produced in oxidation reactions, with free chlorine, of water samples with humic acids, in different concentrations and reaction time. This research also studied the presence of the bromide ion, to evaluate, qualitatively and quantitatively, the different species of T
Publicado em: 2005
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4. Formação e remoção de trihalometanos em aguas de abastecimento utilizando permanganato de potassio e carvão ativado em po / Trihalomethane formation and remotion in drinking water using potassium permanganate and powdered activated carbon
The present research had for objective to analyze the formation of THM through the use of potassium permanganate, isolated or associate with free chlorine, in the process of pre-oxidation, and, in a second stage, to evaluate the removal efficiency of these by-products through the adsorption in powdered activated carbon followed by conventional treatment. The
Publicado em: 2005
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5. Sintese formal do adoçante natural (-)-monatina
In this work we describe the asymmetric formal synthesis of (-)-monatin [(3-indolyl)-2-amino-4-carboxy-4-hydroxypentanoic acid), a powerful natural sweetener, isolated from roots of the african plant Schlerochiton ilicifolius. Monatin exhibit a sweet taste 1400 times more powerful than that of sucrose. (-)-Monatin bears two stereogenic centers, namely, 2S an
Publicado em: 2003
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6. An improved synthesis of oligodeoxynucleotide N3'-->P5' phosphoramidates and their chimera using hindered phosphoramidite monomers and a novel handle for reverse phase purification.
Oligodeoxynucleotide N3'-->P5' phosphoramidates are promising candidates for antisense therapeutics, as well as for diagnostic applications. We recently reported a new method for the synthesis of these oligonucleotide analogs which makes use of a phosphoramidite amine-exchange reaction in the key coupling step. We report herein an improved set of monomers th
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7. A new activity for an old enzyme: Escherichia coli bacterial alkaline phosphatase is a phosphite-dependent hydrogenase
Genetic analysis indicates that Escherichia coli possesses two independent pathways for oxidation of phosphite (Pt) to phosphate. One pathway depends on the 14-gene phn operon, which encodes the enzyme C-P lyase. The other pathway depends on the phoA locus, which encodes bacterial alkaline phosphatase (BAP). Transposon mutagenesis studies strongly suggest th
National Academy of Sciences.
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8. Purification of a manganese-containing protein involved in photosynthetic oxygen evolution and its use in reconstituting an active membrane
Extraction of thylakoid membranes with cholate in the presence of ammonium sulfate inactivated oxygen evolution and liberated a managanese-containing protein. This protein could be combined with preformed liposomes containing the depleted thylakoid membranes to restore 85% of the original oxygen-evolution activity. The protein did not affect the primary phot
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9. Purification of Extracellular Cholesterol Oxidase with High Activity in the Presence of Organic Solvents from Pseudomonas sp. Strain ST-200
Extracellular cholesterol oxidase of Pseudomonas sp. strain ST-200 was purified from the culture supernatant. This oxidase contained bound flavin and was categorized as a 3β-hydroxysteroid oxidase, converting 3β-hydroxyl groups to keto groups. The molecular mass was 60 kDa. The enzyme was stable at pH 4 to 11 and active at pH 5.0 to 8.5, showing optimal ac
American Society for Microbiology.
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10. Metabolism of Cyclohexane Carboxylic Acid by Alcaligenes Strain W1
Thirty-three microorganisms capable of growth with cyclohexane carboxylate as the sole source of carbon were isolated from mud, water, and soil samples from the Aberystwyth area. Preliminary screening and whole-cell oxidation studies suggested that, with one exception, all of the strains metabolized the growth substrate by beta-oxidation of the coenzyme A es
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11. Solid phase synthesis of oligodeoxyribonucleoside phosphorodithioates from thiophosphoramidites.
Oligonucleoside phosphorodithioates 1 are modified DNA sequences with potential use as antisense oligonucleotides. The preparation of up to 20-mers containing all four bases by solid phase synthesis is described, with details on the preparation of the four monomer units (protected nucleoside thiophosphoramidites 2), the conditions used for the assembly of th
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12. Characterization of the pyrogallol-phloroglucinol isomerase of Eubacterium oxidoreducens.
Cell extracts of Eubacterium oxidoreducens, in the presence of dimethyl sulfoxide, catalyzed the conversion of pyrogallol to phloroglucinol with methyl sulfide as a product. The isomerization reaction also proceeded when 1,2,3,5-benzenetetrol was present rather than dimethyl sulfoxide. An assay to quantitate this activity was developed. The assay followed th