Avaliação do desempenho da cinza do bagaço de cana-de-açúcar na adsorção de fipronil
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Data
2020-08-24
Autores
Barbosa, Larissa Maria de Souza
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Universidade Estadual Paulista (Unesp)
Resumo
Em estações de tratamento de água a eficiência de remoção de determinados pesticidas não ultrapassa 40% sendo necessária a associação de processos mais eficazes para a remoção total destes microcontaminantes. A adsorção está entre os processos aplicados no tratamento das águas naturais para diminuir as concentrações de pesticidas e, dentro desse cenário, a biomassa residual vem ganhando destaque por ser um material renovável, de baixo custo, abundante na natureza, por requerer pouco processamento e ter grande potencial de adsorção. Este trabalho teve como objetivo estudar a adsorção do fipronil utilizando a cinza do bagaço de cana-de-açúcar como material adsorvente. Para isso, foram realizados ensaios de adsorção em batelada e ensaios de Jar Test. A análise do fipronil foi realizada por HPLC-MS/MS. Aos resultados obtidos nos ensaios foram aplicadas isotermas: Langmuir, Freundlich e Tempkin, tendo-se verificado que a que melhor descreve os resultados é a de Freundlich. Verificou-se ainda que as porcentagens de remoção alcançadas com a cinza (da ordem de 75 – 80 %) são inferiores às porcentagens de remoção alcançadas com o carvão ativado (da ordem de 79 – 97 %), o que se justifica pelo tratamento térmico e químico realizado na ativação dos carvões ativados. A aplicação dos adsorventes em Jar test, com água bruta de elevada turbidez provocou aumento na turbidez remanescente da água e resultou em porcentagens inferiores de remoção do pesticida. Ainda assim, em função das cinzas do bagaço de cana-de-açúcar serem um resíduo gerado em atividade industrial de grande magnitude nacional e considerando os preceitos de sustentabilidade e da economia circular a utilização deste tipo de material para remoção de pesticidas demonstra ser uma alternativa ambientalmente sustentável.
In water treatment plants, the efficiency of removal of certain pesticides does not exceed 40%, being necessary association with more effective processes for completely microcontaminants removal. Adsorption is among the processes applied in the treatment of natural waters to reduce pesticide concentrations and, within this scenario, the residual biomass has been gaining prominence for being a renewable, low-cost material, abundant in nature, requiring little processing and having great potential for adsorption. This work aimed to study the adsorption of fipronil using sugarcane bagasse fly ash as an adsorbent material. For this, batch adsorption tests and Jar Test were performed. The analysis of fipronil was performed by HPLC-MS/MS. Isotherms were applied to the results obtained in the tests: Langmuir, Freundlich and Tempkin, and it was found that the one that best describes the results is that of Freundlich. It was also found that the removal percentages achieved with ash (on the order of 75 - 80%) are lower than the removal percentages achieved with activated carbon (on the order of 79 - 97%), which is justified by the heat treatment and chemical carried out in the activation of activated carbon. The application of the adsorbents in Jar test, with raw water of high turbidity caused an increase in the remaining turbidity of the water and resulted in lower percentages of pesticide removal. Even so, due to the sugarcane bagasse ashes being a residue generated in industrial activity of great national magnitude and considering the precepts of sustainability and the circular economy, the use of this type of material for pesticide removal proves to be an alternative environmentally sustainable.
In water treatment plants, the efficiency of removal of certain pesticides does not exceed 40%, being necessary association with more effective processes for completely microcontaminants removal. Adsorption is among the processes applied in the treatment of natural waters to reduce pesticide concentrations and, within this scenario, the residual biomass has been gaining prominence for being a renewable, low-cost material, abundant in nature, requiring little processing and having great potential for adsorption. This work aimed to study the adsorption of fipronil using sugarcane bagasse fly ash as an adsorbent material. For this, batch adsorption tests and Jar Test were performed. The analysis of fipronil was performed by HPLC-MS/MS. Isotherms were applied to the results obtained in the tests: Langmuir, Freundlich and Tempkin, and it was found that the one that best describes the results is that of Freundlich. It was also found that the removal percentages achieved with ash (on the order of 75 - 80%) are lower than the removal percentages achieved with activated carbon (on the order of 79 - 97%), which is justified by the heat treatment and chemical carried out in the activation of activated carbon. The application of the adsorbents in Jar test, with raw water of high turbidity caused an increase in the remaining turbidity of the water and resulted in lower percentages of pesticide removal. Even so, due to the sugarcane bagasse ashes being a residue generated in industrial activity of great national magnitude and considering the precepts of sustainability and the circular economy, the use of this type of material for pesticide removal proves to be an alternative environmentally sustainable.
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Palavras-chave
Pesticidas, Abastecimento de água, Biomassa, Pesticides, Water treatment, Biomass