RESUMO

The effectiveness of Crambe abyssinica Hochst seeds by-product as a biosorbent for the removal of cadmium ions from wastewater was analyzed. The biomass of crambe was characterized by scanning electron microscopy, infrared spectroscopy and determining the point of zero charge. The optimum adsorption conditions obtained were 400 mg of biomass in a solution of pH 6.0 and contact time of 60 min to remove 19.342 mg g(-1) cadmium ions. The isotherms of adsorption were constructed and, according to the mathematical linearization, the best fitting followed the Freundlich and Dubinin-Radushkevich models, describing a multilayer adsorption and chemical interaction, also confirmed by the pseudo-second order model and enthalpy value. In the desorption process, about 79% of cadmium ions that had been adsorbed were recovered. The same conditions applied for studying the isotherms of adsorption and desorption were used for comparative study with activated carbon. It was concluded that the use of crambe by-product as biosorbent for cadmium removal in wastewaters was not only a viable alternative to activated carbon, but also required no previous treatment, so it represents a sustainable material with high applicability and low environmental impact.

Assuntos

RESUMO

Jatropha curcas Linn. conhecido como pinhão manso apresenta teor de óleo entre 35 e 38% em suas sementes, sendo utilizado como alternativa na produção de biodiesel. Porém, essa cultura apresenta frutificação desuniforme, o que desfavorece a determinação do período ideal de colheita. Desta forma, esse trabalho objetivou relacionar a coloração das sementes de Jatropha curcas Linn. durante o processo de maturação dos frutos com as características germinativas e concentração de óleo, verificando assim a melhor época para a colheita. Utilizando a carta de cores de Munsell, as sementes foram classificadas em 4 estádios: VC (sementes claras de frutos verdes), VE (sementes escuras de frutos verdes), A (sementes de frutos maduros presos à árvore) e C (sementes ao chão). Foi realizado o teste de germinação, umidade, matéria seca e teor de óleo das sementes. As sementes dos frutos secos presos à árvore (estádio A) resultaram em maior germinação, cerca de 25%, pois possuíam maior massa seca (90.51%) e menor teor de água (9.49%). No estádio A as sementes apresentaram também a maior concentração de óleo, que foi de 47.36% (amêndoa), sendo, portanto, o estádio mais indicado para a colheita dos frutos. As sementes claras de frutos verdes (VC), não apresentaram germinação satisfatória (1.25%). A cor do fruto é um parâmetro para indicação de maturidade fisiológica de sementes de Jatropha curcas Linn.

Jatropha curcas Linn., known as physic nut, is a plant that has oil content between 35 and 38%, being used as an alternative for producing biodiesel. However, this culture has uneven fruiting, which discourages the harvest period. This study aimed to relate the color of the seeds during fruit maturation and germination characteristics with the oil concentration, confirming the best time for harvest. Using the Munsell color chart the seeds were classified into four stages: VC (light seeds of unripe fruits), VE (dark seeds of unripe fruits), A (seeds of fruits attached to the tree) and C (seeds to the ground). It was conducted the germination test, moisture, dry matter and oil content. The seeds of fruits that were attached to the tree (level A) obtained better results in test of germination, about 25% because they had higher dry matter (90.51%) and lower water content (9.49%). They also had the largest concentration of oil, which was 47.36% (almond), and therefore, the best stage for harvesting. The light seeds of unripe fruits (VC), did not obtain satisfactory germination (1.25%), indicating that the color of the fruits can be a parameter for physiological maturity of Jatropha curcas Linn.

Assuntos

RESUMO

Jatropha curcas Linn. conhecido como pinhão manso apresenta teor de óleo entre 35 e 38% em suas sementes, sendo utilizado como alternativa na produção de biodiesel. Porém, essa cultura apresenta frutificação desuniforme, o que desfavorece a determinação do período ideal de colheita. Desta forma, esse trabalho objetivou relacionar a coloração das sementes de Jatropha curcas Linn. durante o processo de maturação dos frutos com as características germinativas e concentração de óleo, verificando assim a melhor época para a colheita. Utilizando a carta de cores de Munsell, as sementes foram classificadas em 4 estádios: VC (sementes claras de frutos verdes), VE (sementes escuras de frutos verdes), A (sementes de frutos maduros presos à árvore) e C (sementes ao chão). Foi realizado o teste de germinação, umidade, matéria seca e teor de óleo das sementes. As sementes dos frutos secos presos à árvore (estádio A) resultaram em maior germinação, cerca de 25%, pois possuíam maior massa seca (90.51%) e menor teor de água (9.49%). No estádio A as sementes apresentaram também a maior concentração de óleo, que foi de 47.36% (amêndoa), sendo, portanto, o estádio mais indicado para a colheita dos frutos. As sementes claras de frutos verdes (VC), não apresentaram germinação satisfatória (1.25%). A cor do fruto é um parâmetro para indicação de maturidade fisiológica de sementes de Jatropha curcas Linn.(AU)

Jatropha curcas Linn., known as physic nut, is a plant that has oil content between 35 and 38%, being used as an alternative for producing biodiesel. However, this culture has uneven fruiting, which discourages the harvest period. This study aimed to relate the color of the seeds during fruit maturation and germination characteristics with the oil concentration, confirming the best time for harvest. Using the Munsell color chart the seeds were classified into four stages: VC (light seeds of unripe fruits), VE (dark seeds of unripe fruits), A (seeds of fruits attached to the tree) and C (seeds to the ground). It was conducted the germination test, moisture, dry matter and oil content. The seeds of fruits that were attached to the tree (level A) obtained better results in test of germination, about 25% because they had higher dry matter (90.51%) and lower water content (9.49%). They also had the largest concentration of oil, which was 47.36% (almond), and therefore, the best stage for harvesting. The light seeds of unripe fruits (VC), did not obtain satisfactory germination (1.25%), indicating that the color of the fruits can be a parameter for physiological maturity of Jatropha curcas Linn.(AU)

Assuntos