Estudo de biochar de capim Napier e avaliação de sua capacidade de adsorção de metais
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Data
2023-05-25
Autores
Toqueti, Flávia
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Universidade Estadual Paulista (Unesp)
Resumo
Na atualidade, existem fortes evidências que as atividades humanas vêm causando intensos impactos nos sistemas terrestres e sua resiliência, diante do aumento populacional e suas pressões sobre o meio, fazendo-se urgente ações que integrem o desenvolvimento contínuo das sociedades à manutenção dos sistemas terrestres, garantindo sua resiliência. De acordo ao conceito das fronteiras planetárias, a Terra contém limites ambientais, os quais sofrem perturbações a partir das ações humanas sendo que a violação de qualquer dessas fronteiras coloca o planeta em risco, podendo derivar em alterações irreversíveis. Muitas dessas fronteiras já tiveram seus valores-limite extrapolados, como o da água e o da poluição ambiental. Diante deste quadro, a busca por soluções mitigadoras torna-se imprescindível para a garantia da resiliência planetária e seus recursos a médio e longo prazo, o que é de fundamental importância para a qualidade e existência dos sistemas vivos. Como potencial mitigador, o biochar, obtido pela queima de biomassa de diferentes resíduos agrícolas com pouco ou nenhum oxigênio, vem sendo estudado para diversas aplicações, como a melhoria da qualidade das águas, por ser um adsorvente de baixo custo e rico em carbono, além de gerar energia em sua produção através do processo de pirólise tornando-se ainda um potencial substituto para combustíveis fósseis. Em função de suas qualidades, este trabalho se propôs a estudar e produzir biochar a partir de capim Napier (Pennisetum purpureum) em propriedade agrícola, utilizando um fogão Anila, capaz de gerar energia com baixa emissão de gases. O biochar produzido neste fogão foi comparado ao biochar produzido em laboratório e posteriormente testado na adsorção de chumbo em solução aquosa. O capim escolhido primeiramente foi submetido à análise termogravimétrica - análise térmica diferencial simultânea (TG-DTA) e à Termogravimetria derivada (DTG) para determinar sua resistência térmica e seu comportamento pirolítico. A caracterização do biochar foi feita por Microscopia Eletrônica de Varredura (MEV), Espectrometria por Energia Dispersiva de Raios X (EDS-MEV) e Espectroscopia na região do Infravermelho com método de refletância total atenuada (FTIR ATR) e a capacidade adsortiva do biochar para o chumbo teve sua quantificação feita por Espectrometria de Emissão Óptica com Plasma Acoplado Indutivamente (ICP-OES). Os resultados obtidos demonstraram que o biochar produzido no fogão Anila a uma temperatura média de 257 ºC apresenta os mesmos grupos funcionais que o produzido em laboratório na mesma temperatura. Além disso, o biochar produzido a partir de capim colhido fresco e seco ao sol por 4 dias apresentou um melhor resultado para a adsorção de chumbo (67,68% de remoção). Os resultados deste trabalho mostram que o biochar produzido a partir de capim napiê pode ser obtido em fogão convencional, mostrando-se uma excelente tecnologia social para a mitigação de contaminação local por metais, contribuindo para a melhoria global avanço sobre as fronteiras planetárias.
Currently, there is strong evidence that human activities have been causing intense impacts on Earth systems and their resilience, in the face of population growth and its pressures on the environment, making urgent actions that integrate the continuous development of societies to the maintenance of Earth systems, ensuring its resilience. According to the concept of planetary borders, the Earth contains environmental limits, which are disturbed by human actions, and the violation of any of these borders puts the planet at risk, which may lead to irreversible changes. Many of these borders have already had their limit values extrapolated, such as water and environmental pollution. Given this situation, the search for mitigating solutions becomes essential to guarantee planetary resilience and its resources in the medium and long term, which is of fundamental importance for the quality and existence of living systems. As a mitigating potential, biochar, obtained by burning biomass from different agricultural residues with little or no oxygen, has been studied for several applications, such as improving water quality, as it is a low-cost adsorbent and rich in carbon, in addition to to generate energy in its production through the pyrolysis process, making it a potential substitute for fossil fuels. Due to its qualities, this work proposed to study and produce biochar from Napier grass (Pennisetum purpureum) in agricultural property, using an Anila stove, capable of generating energy with low gas emissions. The biochar produced in this stove was compared to the biochar produced in the laboratory and later tested in the adsorption of lead in aqueous solution. The chosen grass was first submitted to thermogravimetric analysis - simultaneous differential thermal analysis (TG-DTA) and derived thermogravimetry (DTG) to determine its thermal resistance and its pyrolytic behavior. The characterization of the biochar was performed by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS-SEM) and Infrared Spectroscopy with attenuated total reflectance method (FTIR ATR) and the adsorptive capacity of biochar to lead was quantified by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results obtained showed that the biochar produced in the Anila stove at an average temperature of 257ºC has the same functional groups as the one produced in the laboratory at the same temperature. In addition, the biochar produced from freshly harvested grass and dried in the sun for 4 days showed a better result for lead adsorption (67.68% removal). The results of this work show that the biochar produced from napiê grass can be obtained in a conventional stove, proving to be an excellent social technology for the mitigation of local contamination by metals, contributing to the global progress on planetary boundaries.
Currently, there is strong evidence that human activities have been causing intense impacts on Earth systems and their resilience, in the face of population growth and its pressures on the environment, making urgent actions that integrate the continuous development of societies to the maintenance of Earth systems, ensuring its resilience. According to the concept of planetary borders, the Earth contains environmental limits, which are disturbed by human actions, and the violation of any of these borders puts the planet at risk, which may lead to irreversible changes. Many of these borders have already had their limit values extrapolated, such as water and environmental pollution. Given this situation, the search for mitigating solutions becomes essential to guarantee planetary resilience and its resources in the medium and long term, which is of fundamental importance for the quality and existence of living systems. As a mitigating potential, biochar, obtained by burning biomass from different agricultural residues with little or no oxygen, has been studied for several applications, such as improving water quality, as it is a low-cost adsorbent and rich in carbon, in addition to to generate energy in its production through the pyrolysis process, making it a potential substitute for fossil fuels. Due to its qualities, this work proposed to study and produce biochar from Napier grass (Pennisetum purpureum) in agricultural property, using an Anila stove, capable of generating energy with low gas emissions. The biochar produced in this stove was compared to the biochar produced in the laboratory and later tested in the adsorption of lead in aqueous solution. The chosen grass was first submitted to thermogravimetric analysis - simultaneous differential thermal analysis (TG-DTA) and derived thermogravimetry (DTG) to determine its thermal resistance and its pyrolytic behavior. The characterization of the biochar was performed by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS-SEM) and Infrared Spectroscopy with attenuated total reflectance method (FTIR ATR) and the adsorptive capacity of biochar to lead was quantified by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results obtained showed that the biochar produced in the Anila stove at an average temperature of 257ºC has the same functional groups as the one produced in the laboratory at the same temperature. In addition, the biochar produced from freshly harvested grass and dried in the sun for 4 days showed a better result for lead adsorption (67.68% removal). The results of this work show that the biochar produced from napiê grass can be obtained in a conventional stove, proving to be an excellent social technology for the mitigation of local contamination by metals, contributing to the global progress on planetary boundaries.
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Palavras-chave
Biochar, Capim Napier, Pennisetum purpureum, Fogão Anila, Adsorção, Napier grass, Anila stove, Adsorption