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Abstract(s)
A crescente necessidade de soluções sustentáveis, impulsiona a economia circular através da reutilização de resíduos agrícolas, para fabricar materiais utilizáveis no setor agrícola, especificamente vasos biodegradáveis. Estes vasos têm o potencial de substituir os tradicionais vasos de plástico, que apresentam problemas ambientais significativos. Este trabalho teve como objetivos caracterizar vasos biodegradáveis comercializados (vasos de coco, pasta de papel, TNT e turfa); avaliar as suas propriedades físicas, químicas e mecânicas; estudar a biodegradação dos vasos em diferentes condições de solo; analisar o impacto dos vasos biodegradáveis no crescimento de tomateiros; e explorar o uso de resíduos agrícolas (casca de bolota, noz, cortiça, madeira e serrim) e resinas (goma arábica e colofónia) para a potencial produção de vasos
biodegradáveis. Os parâmetros avaliados incluíram a capacidade de retenção de água, análise estrutural por FTIR, propriedades mecânicas, teor de cinzas, concentração de nutrientes, biodegradabilidade e impacto no crescimento de tomateiros. Verificou-se que o vaso de pasta de papel pode reter quatro vezes a sua massa em água, levando cinco semanas para atingir essa saturação e cerca de 24 horas para secar completamente em condições ambientais. O FTIR identificou os principais grupos funcionais dos componentes lenhocelulósicos, como celulose, hemicelulose e lignina. Os ensaios mostraram que os vasos de coco possuem melhores propriedades mecânicas, com um módulo de Young de 3 305 MPa e uma tensão de cedência de 392 MPa. O teor de cinzas foi geralmente inferior a 5 % da massa seca nos vasos biodegradáveis. Quanto à concentração de nutrientes, foi determinada uma concentração máxima de macro e
micronutrientes de aproximadamente 58 128 mg/kg de peso seco nos vasos de pasta de papel, 30% superior aos outros vasos. Após seis meses enterrados no solo, os vasos de coco, pasta de papel e turfa degradaram-se em 30 %, 40 % e 60 % da massa, respetivamente, sem produzir micropartículas inertes e facilitando a penetração rápida das raízes no solo. Os ensaios em solos de turfa mostraram um bom crescimento dos tomateiros, especialmente nos vasos de coco, com um peso médio total de 55 g num período de três meses (abril a junho). Além disso, foram analisados resíduos de casca de bolota, noz, cortiça, madeira e serrim, e resinas de goma arábica e colofónia (resina de pinheiro) para a potencial produção de vasos biodegradáveis. Determinouse teores de humidade e cinzas inferiores a 5 % e 15 %, respetivamente, com maior concentração
de minerais na cortiça (51 232 mg/kg seco) e goma arábica (43 235 mg/kg seco), ideais para serem
incorporados nos vasos. Foram extraídos taninos das cascas de bolota e utilizados num ensaio preliminar para a produção de polímeros com potencial aplicação na fabricação de vasos biodegradáveis. Os taninos são compostos fenólicos naturais que podem formar polímeros rígidos quando combinados com agentes de ligação apropriados. Neste estudo, as condições ótimas para a polimerização dos taninos foram estabelecidas utilizando 6 g de taninos, 12 mL de glioxal [40% (m/m)], um pH de 9,6, temperatura de 80 °C e um tempo de polimerização de 60 minutos. Esta formulação mostrou-se eficaz na criação de uma matriz polimérica robusta adequada para a produção de vasos biodegradáveis. Conclui-se que os vasos de TNT não são biodegradáveis, enquanto os outros vasos são bons substitutos para os vasos agrícolas convencionais de plástico, devido às suas propriedades adequadas para a plantação e promoção da economia circular. Os
vasos de coco foram considerados os mais indicados para essa substituição. A utilização de resíduos agrícolas e resinas naturais mostrou-se promissora para a produção de vasos biodegradáveis com características adequadas, contribuindo para a sustentabilidade e a economia circular.
The growing need for sustainable solutions drives the circular economy through the reuse of agricultural waste to manufacture materials usable in the agricultural sector, specifically biodegradable pots. These pots have the potential to replace traditional plastic pots, which present significant environmental problems. This study aimed to characterize commercially available biodegradable pots (coconut, paper pulp, non-woven fabric (TNT), and peat pots); evaluate their physical, chemical, and mechanical properties; study the biodegradation of the pots in different soil conditions; analyze the impact of biodegradable pots on the growth of tomato plants; and explore the use of agricultural waste (acorn shell, walnut shell, cork, wood, and sawdust) and resins (gum arabic and colophony) for the potential production of biodegradable pots. The parameters evaluated included water retention capacity, FTIR structural analysis, mechanical properties, ash content, nutrient concentration, biodegradability, and impact on tomato plant growth. It was found that the paper pulp pot can retain four times its mass in water, taking five weeks to reach this saturation and about 24 hours to dry completely under environmental conditions. FTIR identified the main functional groups of lignocellulosic components, such as cellulose, hemicellulose, and lignin. Tests showed coconut pots have better mechanical properties, with a Young's modulus of 3 of 3 305 MPa and a yield stress of 392 MPa. The ash content was generally below 5 % of the dry mass in the biodegradable pots. Regarding nutrient concentration, a maximum concentration of macro and micronutrients of approximately 58 128 mg/kg of dry weight was determined in the paper pulp pots, 30 % higher than the others. After six months buried in the soil, the coconut, paper pulp, and peat pots degraded by 30 %, 40 %, and 60 % of the mass, respectively, without producing inert microparticles and facilitating the rapid penetration of roots into the soil. Tests in peat soils showed good growth of tomato plants, especially in the coconut pots, with an average total weight of 55 g over three months (April to June). Additionally, agricultural residues from acorn shell, walnut shell, cork, wood, sawdust, and resins from gum gum rom gum arabic and colophony (pine resin) were analyzed for the potential production of biodegradable pots. Moisture and ash content were determined to be below 5% and 15%, respectively, with a higher mineral concentration in cork (51 232 mg/kg dry) and gum arabic (43 235 mg/kg dry), ideal for incorporation into the pots. Extraction and Polymerization of Tannins: Tannins were extracted from acorn shells and used in a preliminary trial to producefor the production ofwith potential application in the manufacture of biodegradable pots. Tannins are natural phenolic compounds that can form rigid polymers when combined with appropriate binding agents. In this study, the optimal conditions for tannin polymerization were established using 6 g of tannins, 12 mL of glyoxal [40 % (w/w)], a pH of 9.6, a temperature of 80 °C, and a polymerization time of 60 minutes. This formulation proved effective in creating a robust polymeric matrix suitable for producing biodegradable pots. It was concluded that TNT pots are not biodegradable, while the other pots are good substitutes for conventional plastic agricultural pots, due to their suitable properties for planting and promoting the circular economy. Coconut pots were considered the most suitable for this replacement. The use of agricultural residues and natural resins proved promising to produce biodegradable pots with adequate characteristics, contributing to sustainability and the circular economy.
The growing need for sustainable solutions drives the circular economy through the reuse of agricultural waste to manufacture materials usable in the agricultural sector, specifically biodegradable pots. These pots have the potential to replace traditional plastic pots, which present significant environmental problems. This study aimed to characterize commercially available biodegradable pots (coconut, paper pulp, non-woven fabric (TNT), and peat pots); evaluate their physical, chemical, and mechanical properties; study the biodegradation of the pots in different soil conditions; analyze the impact of biodegradable pots on the growth of tomato plants; and explore the use of agricultural waste (acorn shell, walnut shell, cork, wood, and sawdust) and resins (gum arabic and colophony) for the potential production of biodegradable pots. The parameters evaluated included water retention capacity, FTIR structural analysis, mechanical properties, ash content, nutrient concentration, biodegradability, and impact on tomato plant growth. It was found that the paper pulp pot can retain four times its mass in water, taking five weeks to reach this saturation and about 24 hours to dry completely under environmental conditions. FTIR identified the main functional groups of lignocellulosic components, such as cellulose, hemicellulose, and lignin. Tests showed coconut pots have better mechanical properties, with a Young's modulus of 3 of 3 305 MPa and a yield stress of 392 MPa. The ash content was generally below 5 % of the dry mass in the biodegradable pots. Regarding nutrient concentration, a maximum concentration of macro and micronutrients of approximately 58 128 mg/kg of dry weight was determined in the paper pulp pots, 30 % higher than the others. After six months buried in the soil, the coconut, paper pulp, and peat pots degraded by 30 %, 40 %, and 60 % of the mass, respectively, without producing inert microparticles and facilitating the rapid penetration of roots into the soil. Tests in peat soils showed good growth of tomato plants, especially in the coconut pots, with an average total weight of 55 g over three months (April to June). Additionally, agricultural residues from acorn shell, walnut shell, cork, wood, sawdust, and resins from gum gum rom gum arabic and colophony (pine resin) were analyzed for the potential production of biodegradable pots. Moisture and ash content were determined to be below 5% and 15%, respectively, with a higher mineral concentration in cork (51 232 mg/kg dry) and gum arabic (43 235 mg/kg dry), ideal for incorporation into the pots. Extraction and Polymerization of Tannins: Tannins were extracted from acorn shells and used in a preliminary trial to producefor the production ofwith potential application in the manufacture of biodegradable pots. Tannins are natural phenolic compounds that can form rigid polymers when combined with appropriate binding agents. In this study, the optimal conditions for tannin polymerization were established using 6 g of tannins, 12 mL of glyoxal [40 % (w/w)], a pH of 9.6, a temperature of 80 °C, and a polymerization time of 60 minutes. This formulation proved effective in creating a robust polymeric matrix suitable for producing biodegradable pots. It was concluded that TNT pots are not biodegradable, while the other pots are good substitutes for conventional plastic agricultural pots, due to their suitable properties for planting and promoting the circular economy. Coconut pots were considered the most suitable for this replacement. The use of agricultural residues and natural resins proved promising to produce biodegradable pots with adequate characteristics, contributing to sustainability and the circular economy.
Description
Keywords
Biodegradable pots Characterization Biomass Resins Soils Minerals Vasos biodegradáveis Caracterização Biomassa Resinas Solos Minerais