Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia
Autor(a) principal: | |
---|---|
Data de Publicação: | 2014 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/6306 |
Resumo: | The efficient use of fertilizers, especially nitrogen ones, is essential and strategic for the obtention of maximum economic crop yields and to minimize the loss of nutrients into the environment. Among the technologies that can possibly contribute to the effective use of fertilizers and, consequently, with solutions to the environmental problems caused, are the systems of slow or controlled release; among these systems, are the ones based on the association of lamellar materials and/or polymers to fertilizers. Thus, the objective of this study was to analize the diffusion behavior of urea, when associated with an exfoliated clay mineral (montmorillonite MMT) in its structure, with or without the presence of interface-modifying polymers thus obtaining a nanocomposite. Manufacturing process used- the extrusion of a plastic mixture - is simple and can be scaled up, allowing granule production without high costs. In the first part, nanocomposites were obtained by an extrusion process, from only MMT and the fertilizer urea (nitrogen source) at different mass ratios (1:1; 1:2 and 1:4). From the results of the characterization of these materials, it is possible to observe that urea served as a dispersant for MMT, requiring lower levels of water for processing, allowing the obtention of granular materials, by extrusion, with a mechanical strength superior to the pure urea granule. Furthermore, the presence of MMT generates a retaining means for urea (Ur), through which it has to spread, acting as a physical barrier, observed by the slow release of urea in water. In the second part of the study, two other groups of nanocomposites were prepared, using the ratio 1:4 MMT/urea, adding different percentages (1, 2 and 4% in relation to the total weight) of two different polymers: polyacrylamide hydrogel (HG) and polycaprolactone (PCL). The addition of HG (hydrophilic) to the abovementioned composite generated a new interface between these materials, with stronger interactions, resulting in a significant improvement in the mechanical strength of the mixture, besides presenting a slower kinetic release behavior of urea, when compared to the composite 1:4 MMT/Ur. On the other hand, the presence of PCL produced composites with a more segregated porous structure, irregular surface morphology, interfered with the diffusion process of urea, but did not improve significantly the resistance of the mixture. Composites were also able to reduce the emission of N2O, when applied to a soil planted with wheat, showing, indirectly, an effect on the diffusion of urea to the soil. In the end, a test was conducted for the determination of mineralizable nitrogen in an incubated soil, which showed a mineralization comparable with the pure urea for all nanocomposites, but a representative difference between the tested materials was not observed. This indicates that further studies are needed to better the comprehension of these results. |
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Pereira, Elaine InácioOliveira, Cauê Ribeiro dehttp://lattes.cnpq.br/5321313558714462http://lattes.cnpq.br/8672166906928439eb1248df-684c-4ff1-9003-717c4bb550c12016-06-02T20:34:53Z2014-08-052016-06-02T20:34:53Z2014-04-04PEREIRA, Elaine Inácio. Study of the slow release fertilizer process from nanocomposite of urea matrix. 2014. 110 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2014.https://repositorio.ufscar.br/handle/ufscar/6306The efficient use of fertilizers, especially nitrogen ones, is essential and strategic for the obtention of maximum economic crop yields and to minimize the loss of nutrients into the environment. Among the technologies that can possibly contribute to the effective use of fertilizers and, consequently, with solutions to the environmental problems caused, are the systems of slow or controlled release; among these systems, are the ones based on the association of lamellar materials and/or polymers to fertilizers. Thus, the objective of this study was to analize the diffusion behavior of urea, when associated with an exfoliated clay mineral (montmorillonite MMT) in its structure, with or without the presence of interface-modifying polymers thus obtaining a nanocomposite. Manufacturing process used- the extrusion of a plastic mixture - is simple and can be scaled up, allowing granule production without high costs. In the first part, nanocomposites were obtained by an extrusion process, from only MMT and the fertilizer urea (nitrogen source) at different mass ratios (1:1; 1:2 and 1:4). From the results of the characterization of these materials, it is possible to observe that urea served as a dispersant for MMT, requiring lower levels of water for processing, allowing the obtention of granular materials, by extrusion, with a mechanical strength superior to the pure urea granule. Furthermore, the presence of MMT generates a retaining means for urea (Ur), through which it has to spread, acting as a physical barrier, observed by the slow release of urea in water. In the second part of the study, two other groups of nanocomposites were prepared, using the ratio 1:4 MMT/urea, adding different percentages (1, 2 and 4% in relation to the total weight) of two different polymers: polyacrylamide hydrogel (HG) and polycaprolactone (PCL). The addition of HG (hydrophilic) to the abovementioned composite generated a new interface between these materials, with stronger interactions, resulting in a significant improvement in the mechanical strength of the mixture, besides presenting a slower kinetic release behavior of urea, when compared to the composite 1:4 MMT/Ur. On the other hand, the presence of PCL produced composites with a more segregated porous structure, irregular surface morphology, interfered with the diffusion process of urea, but did not improve significantly the resistance of the mixture. Composites were also able to reduce the emission of N2O, when applied to a soil planted with wheat, showing, indirectly, an effect on the diffusion of urea to the soil. In the end, a test was conducted for the determination of mineralizable nitrogen in an incubated soil, which showed a mineralization comparable with the pure urea for all nanocomposites, but a representative difference between the tested materials was not observed. This indicates that further studies are needed to better the comprehension of these results.O uso eficiente de fertilizantes, principalmente os nitrogenados, é essencial e estratégico para a obtenção de produtividade máxima das culturas e para minimizar as perdas de nutrientes para o meio ambiente. Entre as possíveis tecnologias que podem contribuir para o uso eficaz de fertilizantes e, consequentemente, com soluções para os problemas ambientais acarretados estão os sistemas de liberação lenta ou controlada. Dentre esses estão os sistemas baseados na associação de materiais lamelares e/ou polímeros a fertilizantes. Dessa forma, este trabalho teve como objetivo estudar o comportamento difusional da ureia (Ur) quando associada a um argilomineral esfoliado (montmorilonita - MMT), com ou sem a presença de polímeros modificantes da interface obtendo-se assim um nanocompósito. Os nanocompósitos, com altas cargas de nutriente (matriz compósita), foram produzidos por extrusão, um método simples e bem estabelecido que permite produção em grande escala a menores custos. Na primeira parte do trabalho, foram obtidos nanocompósitos a partir somente de MMT e ureia (fonte de nitrogênio) em diferentes relações mássicas (1:1; 1:2 e 1:4). Dos resultados de caracterização pode-se observar que a ureia atuou como um agente dispersante para a MMT, exigindo baixos teores de água para ser processada, permitindo a obtenção de materiais granulares com resistência mecânica superior ao grânulo de ureia pura. Além disso, foi observado pela cinética de liberação da ureia em água que a presença da MMT atua como uma barreira física, gerando um meio de retenção para a ureia. Na segunda parte do trabalho, foram preparados nanocompósitos com a proporção 1:4 de MMT e ureia e diferentes porcentagens (1, 2 e 4% com relação à massa total) dos polímeros hidrogel de poliacrilamida (HG) e policaprolactona (PCL). A adição de HG (hidrofílico) ao compósito gerou uma nova interface entre os seus componentes com interações mais fortes, ocasionando melhora expressiva na resistência mecânica da mistura e um comportamento cinético de liberação da ureia mais lento, quando comparado ao compósito MMT/Ur 1:4. Por outro lado, a presença do PCL proporcionou aos compósitos uma estrutura porosa mais segregada, responsável pela interferência positiva no processo de difusão da ureia. Entretanto a adição desse polímero não promoveu melhora significativa na resistência mecânica da mistura. Os compósitos também foram capazes de diminuir a emissão de N2O quando aplicados em solo semeado com trigo, mostrando, indiretamente, efeito sobre a difusão da ureia para o solo. Por fim, foi conduzido um teste para determinação de nitrogênio mineralizado em solo incubado, o qual mostrou mineralização comparável à ureia pura para todos os nanocompósitos, porém não foi observada diferença representativa entre os materiais. Isso indica que novos estudos são necessários para uma melhor a compreensão desses resultados.Universidade Federal de Sao Carlosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Química - PPGQUFSCarBRFertilizantes nitrogenadosUreiaMontmorilonitaProcesso de extrusãoLiberação lentaCIENCIAS EXATAS E DA TERRA::QUIMICAEstudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureiaStudy of the slow release fertilizer process from nanocomposite of urea matrixinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis-1-119447b82-be97-4aec-a6e8-de69229cbfdeinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL6025.pdfapplication/pdf3278409https://repositorio.ufscar.br/bitstream/ufscar/6306/1/6025.pdf4c9e69ff7393af2a693fc2951e1275edMD51TEXT6025.pdf.txt6025.pdf.txtExtracted texttext/plain0https://repositorio.ufscar.br/bitstream/ufscar/6306/4/6025.pdf.txtd41d8cd98f00b204e9800998ecf8427eMD54THUMBNAIL6025.pdf.jpg6025.pdf.jpgIM Thumbnailimage/jpeg8838https://repositorio.ufscar.br/bitstream/ufscar/6306/5/6025.pdf.jpg541d016604b6b887f89db0a1530027c6MD55ufscar/63062023-09-18 18:31:52.307oai:repositorio.ufscar.br:ufscar/6306Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:52Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
dc.title.alternative.eng.fl_str_mv |
Study of the slow release fertilizer process from nanocomposite of urea matrix |
title |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
spellingShingle |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia Pereira, Elaine Inácio Fertilizantes nitrogenados Ureia Montmorilonita Processo de extrusão Liberação lenta CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
title_full |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
title_fullStr |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
title_full_unstemmed |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
title_sort |
Estudo do processo de liberação lenta de fertilizantes a partir de nanocompósitos de matriz ureia |
author |
Pereira, Elaine Inácio |
author_facet |
Pereira, Elaine Inácio |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/8672166906928439 |
dc.contributor.author.fl_str_mv |
Pereira, Elaine Inácio |
dc.contributor.advisor1.fl_str_mv |
Oliveira, Cauê Ribeiro de |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/5321313558714462 |
dc.contributor.authorID.fl_str_mv |
eb1248df-684c-4ff1-9003-717c4bb550c1 |
contributor_str_mv |
Oliveira, Cauê Ribeiro de |
dc.subject.por.fl_str_mv |
Fertilizantes nitrogenados Ureia Montmorilonita Processo de extrusão Liberação lenta |
topic |
Fertilizantes nitrogenados Ureia Montmorilonita Processo de extrusão Liberação lenta CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
The efficient use of fertilizers, especially nitrogen ones, is essential and strategic for the obtention of maximum economic crop yields and to minimize the loss of nutrients into the environment. Among the technologies that can possibly contribute to the effective use of fertilizers and, consequently, with solutions to the environmental problems caused, are the systems of slow or controlled release; among these systems, are the ones based on the association of lamellar materials and/or polymers to fertilizers. Thus, the objective of this study was to analize the diffusion behavior of urea, when associated with an exfoliated clay mineral (montmorillonite MMT) in its structure, with or without the presence of interface-modifying polymers thus obtaining a nanocomposite. Manufacturing process used- the extrusion of a plastic mixture - is simple and can be scaled up, allowing granule production without high costs. In the first part, nanocomposites were obtained by an extrusion process, from only MMT and the fertilizer urea (nitrogen source) at different mass ratios (1:1; 1:2 and 1:4). From the results of the characterization of these materials, it is possible to observe that urea served as a dispersant for MMT, requiring lower levels of water for processing, allowing the obtention of granular materials, by extrusion, with a mechanical strength superior to the pure urea granule. Furthermore, the presence of MMT generates a retaining means for urea (Ur), through which it has to spread, acting as a physical barrier, observed by the slow release of urea in water. In the second part of the study, two other groups of nanocomposites were prepared, using the ratio 1:4 MMT/urea, adding different percentages (1, 2 and 4% in relation to the total weight) of two different polymers: polyacrylamide hydrogel (HG) and polycaprolactone (PCL). The addition of HG (hydrophilic) to the abovementioned composite generated a new interface between these materials, with stronger interactions, resulting in a significant improvement in the mechanical strength of the mixture, besides presenting a slower kinetic release behavior of urea, when compared to the composite 1:4 MMT/Ur. On the other hand, the presence of PCL produced composites with a more segregated porous structure, irregular surface morphology, interfered with the diffusion process of urea, but did not improve significantly the resistance of the mixture. Composites were also able to reduce the emission of N2O, when applied to a soil planted with wheat, showing, indirectly, an effect on the diffusion of urea to the soil. In the end, a test was conducted for the determination of mineralizable nitrogen in an incubated soil, which showed a mineralization comparable with the pure urea for all nanocomposites, but a representative difference between the tested materials was not observed. This indicates that further studies are needed to better the comprehension of these results. |
publishDate |
2014 |
dc.date.available.fl_str_mv |
2014-08-05 2016-06-02T20:34:53Z |
dc.date.issued.fl_str_mv |
2014-04-04 |
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2016-06-02T20:34:53Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
PEREIRA, Elaine Inácio. Study of the slow release fertilizer process from nanocomposite of urea matrix. 2014. 110 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2014. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/6306 |
identifier_str_mv |
PEREIRA, Elaine Inácio. Study of the slow release fertilizer process from nanocomposite of urea matrix. 2014. 110 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2014. |
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https://repositorio.ufscar.br/handle/ufscar/6306 |
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