Spelling suggestions: "subject:"freundlich isothermal"" "subject:"ereundlich isothermal""
1 |
Desenvolvimento de métodos visando a quantificação de sulfonamidas em medicamentos de uso veterinario e estudos de sorção/dessorção em solos / Development of methods aiming the quantification of sulfonamides in veterinary drugs and studies of adsorption/desorption in soilsDoretto, Keity Margareth, 19-- 08 August 2012 (has links)
Orientador: Susanne Rath / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-21T08:01:07Z (GMT). No. of bitstreams: 1
Doretto_KeityMargareth_D.pdf: 2722057 bytes, checksum: d4c5a2090af2c524cc8d28125e30eaa2 (MD5)
Previous issue date: 2012 / Resumo: Antimicrobianos, entre eles as sulfonamidas, têm sido amplamente utilizados em medicina veterinária para fins terapêuticos e profiláticos. Uma vez excretados os fármacos e/ou metabólitos podem levar a contaminação do meio ambiente e estudos sobre o impacto ambiental ainda são escassos. Em adição, no Brasil, ainda não existe uma fiscalização de medicamentos veterinários. A não conformidade dos medicamentos reflete diretamente na saúde animal, como também é um tópico relevante quanto à segurança alimentar. Assim sendo, métodos foram desenvolvidos e validados para a determinação de sulfadiazina (SDZ), sulfadimetoxina (SDM) e sulfaquinoxalina (SQX) em medicamentos de uso veterinário por cromatografia líquida de alta eficiência associada a um detector de arranjo de fotodiodos (HPLC-DAD). Os resultados obtidos indicam a necessidade de controle de qualidade dos fármacos de uso veterinário comercializados no Brasil. Ainda, o trabalho estudou a sorção da SDZ, SDM e SQX em quatro solos característicos do Estado de São Paulo. Os estudos foram conduzidos conforme recomendação do Guia OECD 106. As sulfonamidas foram quantificadas nas soluções de solo por um método HPLC-DAD previamente validado. Os dados de adsorção/dessorção das sulfonamidas nos quatro solos foram ajustados com isotermas de Freundlich na forma linear ou logarítmica. Um fenômeno de histerese de adsorção/dessorção foi evidente em todos os solos. Os baixos valores do coeficiente de Freundlich (KF) obtidos sugerem fraca adsorção das sulfonamidas nos solos avaliados e, portanto, estas tendem a ser lixiviados e, por sua vez apresentam potencial para contaminar águas superficiais e subterrâneas / Abstract: Antimicrobials, including sulfonamides, have been widely used in veterinary medicine for therapeutic and prophylactic purposes. Once excreted, drugs and/or metabolites can contaminate the environment. Environmental impact studies are still scarce. In addition, in Brazil, there is no surveillance of veterinary medicines. The poor quality of drugs may reflect directly on animal health and is also a topic relevant to food safety. Therefore, methods were developed and validated for the determination of sulfadiazine (SDZ), sulfadimethoxine (SDM) and sulfaquinoxaline (SQX) in veterinary drugs, using high performance liquid chromatography coupled to a photodiode array detector (HPLC-DAD). The obtained results indicate the need for a quality control program of veterinary drugs comercialized in Brazil. Moreover, the present work aim studied the sorption of sulfonamides (SDZ, SDM and SQX) in four characteristic soils of the State of São Paulo. The studies were conducted as recommended by the OECD Guidelines 106. The sulfonamides were quantified in the soil solutions by a previously validated HPLC-DAD method. Adsorption/desorption data of sulfonamides in soils were fitted to Freundlich isotherms in the linear or logarithmic forms. A hysteresis of adsorption/desorption was evident in all four soils evaluated. The low values of the Freundlich coefficient (KF) obtained suggest weak adsorption of sulfonamides in soils, and therefore they tend to be leached and present high potential to contaminate surface and groundwater / Doutorado / Quimica Analitica / Doutora em Ciências
|
2 |
Matéria orgânica proveniente de água residuária de suinocultura na interação e transporte de alaclor no soloBosco, Tatiane Cristina Dal 08 August 2011 (has links)
Made available in DSpace on 2017-07-10T19:25:01Z (GMT). No. of bitstreams: 1
tatiane_texto.pdf: 2558616 bytes, checksum: c23ff4ce31df2fb07ce669109433709c (MD5)
Previous issue date: 2011-08-08 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Swine wastewater application into soil to reuse water on cropping provides the addition of
total and dissolved organic matter to soil, which interferes in the dynamics of pesticides in
soil. This study aims at evaluating the effects of total and dissolved organic matter
application from two systems of swine wastewater, biodigestor and lagoon treatments, in
alachlor sorption, desorption, leaching and formation of bound residues into soil. The batch
method was used to test sorption and desorption and the results were presented in
Freundlich isotherms. The evaluation of miscible displacement of alachlor, in soil treated with
total and dissolved organic matter, was performed by disturbed soil columns, by monitoring
the concentration of alachlor in leachate, total organic carbon and pH. Extraction and
quantification of desorption, extractable and bound residues were carried out. After that, it
was registered the chemical fractionation of humic substances in extracts containing organic
matter of low molecular weight, humic acids and fulvic acids, which were characterized by
infrared spectroscopy and total organic carbon concentration. The swine wastewater addition
promoted greater sorption and desorption of alachlor compared to Control. The dissolved
organic matter promoted less sorption of alachlor in soil when compared to total organic
matter, resulting in an increased leaching of alachlor. The dissolved organic matter did not
show desorption residues, only extractable ones. The highest amount of total organic carbon
was in organic matter of low molecular weight, spectroscope characterized, by the presence
of carboxylate anions, which are important in sorption process. The total organic matter has
contributed to the emergence of new sorption sites in soil column and the solids present in its
composition blocked the movement of pesticide, resulting in lower leaching of alachlor. The
dissolved organic matter interacted with alachlor and / or competed with the sorption sites of
soil, promoting greater losses by leaching of this herbicide. / A aplicação de água residuária de suinocultura ao solo como reúso de água na agricultura
resulta na adição de matéria orgânica total e dissolvida, que interferem na dinâmica dos
pesticidas no solo. Objetivou-se avaliar o efeito da aplicação de matéria orgânica total e
dissolvida proveniente de dois sistemas de tratamento de água residuária de suinocultura,
biodigestor e esterqueira, na adsorção, dessorção, lixiviação e formação de resíduos ligados
de alaclor no solo. O método do equilíbrio foi utilizado para o teste de adsorção e dessorção
e os resultados foram apresentados em isotermas de Freundlich. A avaliação do
deslocamento miscível do alaclor no solo tratado com matéria orgânica total e dissolvida foi
realizada por ensaios em colunas de solo deformado, monitorando-se a concentração de
alaclor no lixiviado, teor de carbono orgânico total e pH. Realizou-se a extração e
quantificação dos resíduos dessorvíveis, extraíves e ligados do solo. Na sequência, fez-se o
fracionamento químico das substâncias húmicas em extratos contendo matéria orgânica de
baixo peso molecular, ácidos húmicos e ácidos fúlvicos, que foram caracterizados por
espectroscopia infravermelha e pela concentração de carbono orgânico total. A adição de
água residuária de suinocultura promoveu maior adsorção e dessorção do alaclor
comparado ao Controle. A matéria orgânica dissolvida promoveu menor adsorção de alaclor
ao solo comparada à total, resultando em maior lixiviação. A matéria orgânica dissolvida não
apresentou resíduos dessorvíveis, apenas extraíveis. A maior quantidade de carbono
orgânico total esteve presente na matéria orgânica de baixo peso molecular, caracterizada
espectroscopicamente, pela presença de ânions carboxilatos, importantes no processo de
adsorção. A matéria orgânica total contribuiu com o surgimento de novos sítios de sorção na
coluna de solo e os sólidos presentes em sua composição bloquearam a passagem do
pesticida, resultando em menores perdas de alaclor por lixiviação. A matéria orgânica
dissolvida interagiu com o alaclor e/ou competiu com os sítios sortivos do solo, promovendo
maiores perdas deste herbicida por lixiviação.
|
3 |
Matéria orgânica proveniente de água residuária de suinocultura na interação e transporte de alaclor no soloBosco, Tatiane Cristina Dal 08 August 2011 (has links)
Made available in DSpace on 2017-05-12T14:48:22Z (GMT). No. of bitstreams: 1
tatiane_texto.pdf: 2558616 bytes, checksum: c23ff4ce31df2fb07ce669109433709c (MD5)
Previous issue date: 2011-08-08 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Swine wastewater application into soil to reuse water on cropping provides the addition of
total and dissolved organic matter to soil, which interferes in the dynamics of pesticides in
soil. This study aims at evaluating the effects of total and dissolved organic matter
application from two systems of swine wastewater, biodigestor and lagoon treatments, in
alachlor sorption, desorption, leaching and formation of bound residues into soil. The batch
method was used to test sorption and desorption and the results were presented in
Freundlich isotherms. The evaluation of miscible displacement of alachlor, in soil treated with
total and dissolved organic matter, was performed by disturbed soil columns, by monitoring
the concentration of alachlor in leachate, total organic carbon and pH. Extraction and
quantification of desorption, extractable and bound residues were carried out. After that, it
was registered the chemical fractionation of humic substances in extracts containing organic
matter of low molecular weight, humic acids and fulvic acids, which were characterized by
infrared spectroscopy and total organic carbon concentration. The swine wastewater addition
promoted greater sorption and desorption of alachlor compared to Control. The dissolved
organic matter promoted less sorption of alachlor in soil when compared to total organic
matter, resulting in an increased leaching of alachlor. The dissolved organic matter did not
show desorption residues, only extractable ones. The highest amount of total organic carbon
was in organic matter of low molecular weight, spectroscope characterized, by the presence
of carboxylate anions, which are important in sorption process. The total organic matter has
contributed to the emergence of new sorption sites in soil column and the solids present in its
composition blocked the movement of pesticide, resulting in lower leaching of alachlor. The
dissolved organic matter interacted with alachlor and / or competed with the sorption sites of
soil, promoting greater losses by leaching of this herbicide. / A aplicação de água residuária de suinocultura ao solo como reúso de água na agricultura
resulta na adição de matéria orgânica total e dissolvida, que interferem na dinâmica dos
pesticidas no solo. Objetivou-se avaliar o efeito da aplicação de matéria orgânica total e
dissolvida proveniente de dois sistemas de tratamento de água residuária de suinocultura,
biodigestor e esterqueira, na adsorção, dessorção, lixiviação e formação de resíduos ligados
de alaclor no solo. O método do equilíbrio foi utilizado para o teste de adsorção e dessorção
e os resultados foram apresentados em isotermas de Freundlich. A avaliação do
deslocamento miscível do alaclor no solo tratado com matéria orgânica total e dissolvida foi
realizada por ensaios em colunas de solo deformado, monitorando-se a concentração de
alaclor no lixiviado, teor de carbono orgânico total e pH. Realizou-se a extração e
quantificação dos resíduos dessorvíveis, extraíves e ligados do solo. Na sequência, fez-se o
fracionamento químico das substâncias húmicas em extratos contendo matéria orgânica de
baixo peso molecular, ácidos húmicos e ácidos fúlvicos, que foram caracterizados por
espectroscopia infravermelha e pela concentração de carbono orgânico total. A adição de
água residuária de suinocultura promoveu maior adsorção e dessorção do alaclor
comparado ao Controle. A matéria orgânica dissolvida promoveu menor adsorção de alaclor
ao solo comparada à total, resultando em maior lixiviação. A matéria orgânica dissolvida não
apresentou resíduos dessorvíveis, apenas extraíveis. A maior quantidade de carbono
orgânico total esteve presente na matéria orgânica de baixo peso molecular, caracterizada
espectroscopicamente, pela presença de ânions carboxilatos, importantes no processo de
adsorção. A matéria orgânica total contribuiu com o surgimento de novos sítios de sorção na
coluna de solo e os sólidos presentes em sua composição bloquearam a passagem do
pesticida, resultando em menores perdas de alaclor por lixiviação. A matéria orgânica
dissolvida interagiu com o alaclor e/ou competiu com os sítios sortivos do solo, promovendo
maiores perdas deste herbicida por lixiviação.
|
4 |
Ion exchange resins an functional fibres :a comparative study for the treatment of brine waste waterBongani Ndhlovu Yalala January 2009 (has links)
<p>To improve the adsorption capacity of polyacrylonitrile (PAN) fibres, hydrophilic amidoxime fibres were prepared by subsequent conversion of the cyano groups to an amidoxime group by reacting with hydroxylamine at 80° / C at an optimum amidoximation time of 2 hrs. The amidoxime fibre was hydrolyzed/alkali treated in a solution of sodium hydroxide to enhance or improve the adsorption properties. This was followed by characterization of the amidoxime and hydrolyzed fibres using Scanning electron microscopy (SEM) / Fourier transform Infrared Spectroscopy (FTIR) and exchange capacity (cationic and anionic). SEM showed that the hydrolysis process made the surface of Amidoxime fibre rougher than that of Polyacrylonitrile fibre. FTIR revealed that the hydrolyzed Amidoxime fibres contained conjugated imine (-C=N-) sequences. Functionalization enhanced the sorption of amidoxime fibres by an increase of 20 % in the cationic exchange capacity. This was achieved by the part conversion of the cyano groups into the carboxylic acid groups. The fibres showed faster kinetics largely due the available exchange sites on the surface of the fibres hence the equilibration was achieved much quicker.</p>
|
5 |
Ion exchange resins an functional fibres :a comparative study for the treatment of brine waste waterBongani Ndhlovu Yalala January 2009 (has links)
<p>To improve the adsorption capacity of polyacrylonitrile (PAN) fibres, hydrophilic amidoxime fibres were prepared by subsequent conversion of the cyano groups to an amidoxime group by reacting with hydroxylamine at 80° / C at an optimum amidoximation time of 2 hrs. The amidoxime fibre was hydrolyzed/alkali treated in a solution of sodium hydroxide to enhance or improve the adsorption properties. This was followed by characterization of the amidoxime and hydrolyzed fibres using Scanning electron microscopy (SEM) / Fourier transform Infrared Spectroscopy (FTIR) and exchange capacity (cationic and anionic). SEM showed that the hydrolysis process made the surface of Amidoxime fibre rougher than that of Polyacrylonitrile fibre. FTIR revealed that the hydrolyzed Amidoxime fibres contained conjugated imine (-C=N-) sequences. Functionalization enhanced the sorption of amidoxime fibres by an increase of 20 % in the cationic exchange capacity. This was achieved by the part conversion of the cyano groups into the carboxylic acid groups. The fibres showed faster kinetics largely due the available exchange sites on the surface of the fibres hence the equilibration was achieved much quicker.</p>
|
6 |
Ion exchange resins an functional fibres: a comparative study for the treatment of brine waste waterYalala, Bongani Ndhlovu January 2009 (has links)
Magister Scientiae - MSc / To improve the adsorption capacity of polyacrylonitrile (PAN) fibres, hydrophilic amidoxime fibres were prepared by subsequent conversion of the cyano groups to an amidoxime group by reacting with hydroxylamine at 80°C at an optimum amidoximation time of 2 hrs. The amidoxime fibre was hydrolyzed/alkali treated in a solution of sodium hydroxide to enhance or improve the adsorption properties. This was followed by characterization of the amidoxime and hydrolyzed fibres using Scanning electron microscopy (SEM); Fourier transform Infrared Spectroscopy (FTIR) and exchange capacity (cationic and anionic). SEM showed that the hydrolysis process made the surface of Amidoxime fibre rougher than that of Polyacrylonitrile fibre. FTIR revealed that the hydrolyzed Amidoxime fibres contained conjugated imine (-C=N-) sequences. Functionalization enhanced the sorption of amidoxime fibres by an increase of 20 % in the cationic exchange capacity. This was achieved by the part conversion of the cyano groups into the carboxylic acid groups. The fibres showed faster kinetics largely due the available exchange sites on the surface of the fibres hence the equilibration was achieved much quicker. / South Africa
|
Page generated in 0.0667 seconds