Avaliação da adsorção do cromo em efluente a partir de carvão ativado produzido com palito de erva-mate
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Data
2023-12
Autores
Orientador
Borsoi, Cleide
Banca
Hoehne, Lucélia
Reisdorfer, Gustavo
Título do periódico
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Resumo
A qualidade dos cursos de água vem sendo afetada de diversas maneiras sendo que a principal forma de poluição é através das indústrias, sobretudo pelo descarte incorreto dos resíduos tanto sólidos quanto líquidos. Estes efluentes líquidos podem concentrar metais pesados, com elevado potencial tóxico, como o cromo (Cr). Entre as diversas formas de tratamento destes efluentes está a adsorção com carvão ativado, porém o custo desse material é elevado e, por isso, estão surgindo diversas formas de desenvolvimento de carvão ativado, a partir da utilização de resíduos agroindustriais. Como no Rio Grande do Sul há predomínio do cultivo e do consumo de erva-mate, há elevada geração de resíduos e, portanto, buscando aproveitar os resíduos destas indústrias, aliando isto ao tratamento de efluentes, o objetivo deste estudo é caracterizar e obter resultados satisfatórios a partir de um carvão ativado produzido com os palitos de erva-mate, para a remoção do cromo de efluentes. Para isso, a metodologia utilizada consistiu em ativar o carvão fisicamente (CAF) com pirólise em mufla, a 700 ºC, por 45 min e quimicamente com cloreto de zinco (ZnCl2 ), hidróxido de sódio (NaOH) e ácido fosfórico (H3PO4 ), em proporção 1:1, sendo as amostras sintetizadas denominadas CAZnCl2 , CAH3PO4 e CANaOH e os resultados das análises de adsorção foram comparados ao carvão ativado comercial (CAC). Foram analisados diferentes pH, cujos resultados indicam que o melhor pH de adsorção é o 6, considerando-se a capacidade de adsorção, utilizando-se 0,2 g/L de carvão ativado no tempo de equilíbrio de 3 min, com maior capacidade de adsorção para CAH3PO4 e para CAZnCl2 . Já para as análises envolvendo a variação de concentração de cromo hexavalente (Cr (VI)), a partir de solução de efluente sintético, verificou-se que a maior eficiência foi obtida com CAH3PO4 na concentração de 1,77 mg/L Cr (VI), e durante a análise da variação do tempo de equilíbrio de adsorção, a amostra CAH3PO4 alcançou 90% de remoção de Cr (VI) com 5 min. Para a avaliação da eficiência do carvão ativado, foram elaboradas as isotermas de adsorção a partir dos modelos de Langmuir, Freundlich e de Brunauer, Emmett e Teller (BET), que constataram que o modelo de Freundlich foi o mais satisfatório para todas amostras analisadas. Através dos resultados obtidos, verifica-se que é possível desenvolver carvão ativado utilizando palitos de erva-mate, e que podem ser obtidos resultados satisfatórios na adsorção do Cr.
The quality of watercourses has been affected in several ways, with the main form of pollution being through industries, especially due to the incorrect disposal of both solid and liquid waste. These liquid effluents can concentrate heavy metals, with high toxic potential, such as chromium (Cr). Among the different ways of treating these effluents is adsorption with activated carbon, however the cost of this material is high and, therefore, different ways of developing activated carbon are emerging, using agro-industrial waste.As in Rio Grande do Sul there is a predominance of cultivation and consumption of yerba mate, there is a high generation of waste and, therefore, seeking to take advantage of waste from these industries, combining this with effluent treatment, the objective of this study is to characterize and obtain results satisfactory results from activated carbon produced with yerba mate sticks, for removing chromium from effluents. For this, the methodology used consisted of activating the coal physically (CAF) with pyrolysis in a muffle furnace, at 700 ºC, for 45 min and chemically with zinc chloride (ZnCl2 ), sodium hydroxide (NaOH) and phosphoric acid (H3PO4 ), in a 1:1 ratio, with the synthesized samples being called CAZnCl2 , CAH3PO4 and CANaOH, and the results of the adsorption analyzes were compared to commercial activated carbon (CAC). Different pHs were analyzed, the results of which indicate that the best adsorption pH is 6, considering the adsorption capacity, using 0.2 g/L of activated carbon in the equilibrium time of 3 min, with a greater adsorption capacity. adsorption for CAH3PO4 and for CAZnCl2 . As for the analyzes involving the variation in the concentration of hexavalent chromium (Cr (VI)), from a synthetic effluent solution, it was found that the highest efficiency was obtained with CAH3PO4 at a concentration of 1.77 mg/L Cr (VI ), and during the analysis of the adsorption equilibrium time variation, the CAH3PO4 sample achieved 90% Cr(VI) removal within 5 min. To evaluate the efficiency of activated carbon, adsorption isotherms were created based on the Langmuir, Freundlich and Brunauer, Emmett and Teller (BET) models, which found that the Freundlich model was the most satisfactory for all samples analyzed. Through the results obtained, it can be seen that it is possible to develop activated carbon using yerba mate sticks, and that satisfactory results can be obtained in the adsorption of Cr.
The quality of watercourses has been affected in several ways, with the main form of pollution being through industries, especially due to the incorrect disposal of both solid and liquid waste. These liquid effluents can concentrate heavy metals, with high toxic potential, such as chromium (Cr). Among the different ways of treating these effluents is adsorption with activated carbon, however the cost of this material is high and, therefore, different ways of developing activated carbon are emerging, using agro-industrial waste.As in Rio Grande do Sul there is a predominance of cultivation and consumption of yerba mate, there is a high generation of waste and, therefore, seeking to take advantage of waste from these industries, combining this with effluent treatment, the objective of this study is to characterize and obtain results satisfactory results from activated carbon produced with yerba mate sticks, for removing chromium from effluents. For this, the methodology used consisted of activating the coal physically (CAF) with pyrolysis in a muffle furnace, at 700 ºC, for 45 min and chemically with zinc chloride (ZnCl2 ), sodium hydroxide (NaOH) and phosphoric acid (H3PO4 ), in a 1:1 ratio, with the synthesized samples being called CAZnCl2 , CAH3PO4 and CANaOH, and the results of the adsorption analyzes were compared to commercial activated carbon (CAC). Different pHs were analyzed, the results of which indicate that the best adsorption pH is 6, considering the adsorption capacity, using 0.2 g/L of activated carbon in the equilibrium time of 3 min, with a greater adsorption capacity. adsorption for CAH3PO4 and for CAZnCl2 . As for the analyzes involving the variation in the concentration of hexavalent chromium (Cr (VI)), from a synthetic effluent solution, it was found that the highest efficiency was obtained with CAH3PO4 at a concentration of 1.77 mg/L Cr (VI ), and during the analysis of the adsorption equilibrium time variation, the CAH3PO4 sample achieved 90% Cr(VI) removal within 5 min. To evaluate the efficiency of activated carbon, adsorption isotherms were created based on the Langmuir, Freundlich and Brunauer, Emmett and Teller (BET) models, which found that the Freundlich model was the most satisfactory for all samples analyzed. Through the results obtained, it can be seen that it is possible to develop activated carbon using yerba mate sticks, and that satisfactory results can be obtained in the adsorption of Cr.
Descrição
Palavras-chave
Carvão ativado; Cromo; Palitos de erva-mate; Adsorção; Activated carbon; Chrome; Yerba mate sticks; Adsorption
Citação
PAES, Rafaela Klein. Avaliação da adsorção do cromo em efluente a partir de carvão ativado produzido com palito de erva-mate. 2023. Monografia (Graduação) – Curso de Engenharia Química, Universidade do Vale do Taquari - Univates, Lajeado, 12 dez. 2023. Disponível em: http://hdl.handle.net/10737/4227.