Modificação da celulose para liberação aprimorada de nutrientes agrícolas
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Data
2024-02-21
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Universidade Estadual Paulista (Unesp)
Resumo
Uma das fases mais cruciais da produção agrícola é a fertilização do solo, que exige fornecimento adequado e equilibrado de nutrientes para cultivares, buscando melhoria na produtividade. No entanto, muitos destes nutrientes são perdidos devido à lixiviação e volatilização, entre outros. Como resultado, apenas uma parcela desses componentes é efetivamente utilizada pelo cultivar e soma-se a isso, aplicações inadequadas de fertilizantes causando eutrofização de cursos d'água, impondo a necessidade de adoção de tecnologias que permitam liberação adequada de fertilizantes. Ao reduzir o desperdício, os fertilizantes de libertação aprimorada podem adequar a disponibilidade do conteúdo de nutrientes no solo às plantas, reduzindo a contaminação ambiental. Estudos recentes têm enfatizado o uso de diversas fontes naturais e biodegradáveis, especialmente, biomassa no desenvolvimento de fertilizante de liberação aprimorada em razão de sua biodegradabilidade, propriedades não tóxicas e sendo fonte renovável a um custo consideravelmente baixo. Entretanto, o uso de biopolímeros no desenvolvimento de fertilizantes de libertação melhorada necessita, frequentemente, da introdução de produtos químicos como agentes deslignizantes, reticulantes, precursores de polimerização, solventes orgânicos, líquidos iónicos, entre outros, além de processos de alta complexidade de produção e onerosos. Diante disso, o presente trabalho buscou criar novos fertilizantes de liberação aprimorada, fazendo-se uso de biopolímeros e do menor número possível de componentes químicos. A sequência de ações segue na extração celulose do bagaço de cana-de-açúcar, síntese de fertilizante de liberação aprimorada à base de celulose, caracterização de propriedades e discussão dos mecanismos de liberação de nutrientes. Os resultados mostraram que a celulose I foi convertida em celulose II, além da eliminação de lignina, hemicelulose e outros carboidratos, o que gerou perda de massa em torno de 61%. A esterificação da celulose com anidrido do ácido etilenodiaminotetracético foi comprovada pelas mesmas técnicas de caracterização, assim como a incorporação dos macronutrientes nitrogênio, fósforo e potássio. Na análise química dos macronutrientes NPK obteve-se resultado médio de 73% de liberação no solo em 30 dias e em torno de 15% de liberação em 24 h. Os experimentos comprovaram a eficiência do substrato produzido, quanto a sua capacidade de liberação aprimorada de NPK. Além disso, o uso da celulose como base para o substrato, mostrou-se vantajoso por ser biodegradável e de fonte renovável. Os resultados obtidos são de grande relevância por indicarem, claramente, que os materiais biopoliméricos podem contribuir para o bom desempenho agrícola, na produção de alimentos e, consequente, preservação ambiental.
One of the most crucial phases of agricultural production is soil fertilization, which requires a balanced supply of components for the good development of cultivars and improved productivity. However, many of these components are lost due to leaching and volatilization, among other things. As a result, only a portion of these components is effectively used by the cultivar, and inadequate fertilizer applications have become a source of environmental risks such as the eutrophication of water courses, which brings other undesirable consequences, imposing the need to adopt technologies that allow adequate release of fertilizers. By reducing waste, enhanced release fertilizers can match the availability of soil nutrient content to plants, reducing environmental contamination. Recent studies have emphasized the use of various natural and biodegradable sources, especially biomass, in the development of these enhanced release fertilizers due to their biodegradability, non-toxic properties and renewable source at a considerably low cost. However, the use of biopolymers in the development of improved release fertilizers often requires the introduction of additional chemical products, such as delignizing agents, crosslinkers, polymerization precursors, organic solvents, ionic liquids, etc., or highly complex and costly production processes in agricultural applications. Given this, the present work sought to create new enhanced release fertilizers based on biopolymers using the smallest possible number of chemical components, carrying out several experiments with the following objectives: a) extract cellulose from sugarcane bagasse; b) create cellulose-based improved release fertilizers; c) characterize the properties in search of the best conditions for the synthesis of improved release fertilizers; d) elucidate the link between the chemical structure and nutrient release mechanisms. Studies that produced partial results such as the successful extraction of cellulose from sugarcane bagasse, such as X-ray diffraction analyzes and Fourier transform infrared spectroscopy showed that cellulose was converted from cellulose I to cellulose II, in addition to the elimination of lignin, hemicellulose and other carbohydrates (polioses), which generated a mass loss of around 61.1%. The esterification of cellulose with ethylenediaminetetraacetic acid anhydride was proven using the same techniques, as well as the incorporation of the macronutrients nitrogen, phosphorus and potassium. In the chemical analysis of NPK macronutrients, an average result of 73.4% release into the soil in 30 days and around 15% release in 24 hours was obtained. In short, the tests proved the efficiency of the substrate produced in terms of improved NPK release capacity. Furthermore, the use of cellulose as a substrate base is advantageous because it is biodegradable and a renewable source. The results obtained are of great relevance as they clearly indicate that biopolymeric materials contribute to good agricultural performance in food production and consequent environmental preservation.
One of the most crucial phases of agricultural production is soil fertilization, which requires a balanced supply of components for the good development of cultivars and improved productivity. However, many of these components are lost due to leaching and volatilization, among other things. As a result, only a portion of these components is effectively used by the cultivar, and inadequate fertilizer applications have become a source of environmental risks such as the eutrophication of water courses, which brings other undesirable consequences, imposing the need to adopt technologies that allow adequate release of fertilizers. By reducing waste, enhanced release fertilizers can match the availability of soil nutrient content to plants, reducing environmental contamination. Recent studies have emphasized the use of various natural and biodegradable sources, especially biomass, in the development of these enhanced release fertilizers due to their biodegradability, non-toxic properties and renewable source at a considerably low cost. However, the use of biopolymers in the development of improved release fertilizers often requires the introduction of additional chemical products, such as delignizing agents, crosslinkers, polymerization precursors, organic solvents, ionic liquids, etc., or highly complex and costly production processes in agricultural applications. Given this, the present work sought to create new enhanced release fertilizers based on biopolymers using the smallest possible number of chemical components, carrying out several experiments with the following objectives: a) extract cellulose from sugarcane bagasse; b) create cellulose-based improved release fertilizers; c) characterize the properties in search of the best conditions for the synthesis of improved release fertilizers; d) elucidate the link between the chemical structure and nutrient release mechanisms. Studies that produced partial results such as the successful extraction of cellulose from sugarcane bagasse, such as X-ray diffraction analyzes and Fourier transform infrared spectroscopy showed that cellulose was converted from cellulose I to cellulose II, in addition to the elimination of lignin, hemicellulose and other carbohydrates (polioses), which generated a mass loss of around 61.1%. The esterification of cellulose with ethylenediaminetetraacetic acid anhydride was proven using the same techniques, as well as the incorporation of the macronutrients nitrogen, phosphorus and potassium. In the chemical analysis of NPK macronutrients, an average result of 73.4% release into the soil in 30 days and around 15% release in 24 hours was obtained. In short, the tests proved the efficiency of the substrate produced in terms of improved NPK release capacity. Furthermore, the use of cellulose as a substrate base is advantageous because it is biodegradable and a renewable source. The results obtained are of great relevance as they clearly indicate that biopolymeric materials contribute to good agricultural performance in food production and consequent environmental preservation.
Descrição
Palavras-chave
Biopolímero, Celulose, Substrato, Fertilizante, Liberação aprimorada, Biopolymer, Cellulose, Fertilizer, Enhanced release, Substrate
Como citar
RASZL, Armando José. Modificação da celulose para liberação aprimorada de nutrientes agrícolas. Orientadora: Valquíria de Campos. 2024. 89 p. Dissertação (Mestrado em Ciências Ambientais) - Instituto de Ciência e Tecnologia, Universidade Estadual Paulista "Júlio de Mesquita Filho", Sorocaba, 2024.