Produção e caracterização de material adsorvente a partir de lodo de estação de tratamento de água para a remoção de disruptores endócrinos
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Data
2021-01-15
Autores
Martins, Danubia Santiago
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Universidade Estadual Paulista (Unesp)
Resumo
O saneamento básico enfrenta dificuldades para tratar a água de abastecimento e o esgoto urbano. Parte desses problemas está relacionado aos compostos orgânicos sintéticos e naturais, gerados pela indústria, agricultura e pecuária. Dentre esses compostos, se destacam os disruptores endócrinos. Como agravante, os processos existentes em planta não são suficientes para sua separação/remoção destes poluentes. Além destas causas, o lodo de ETA que é o resíduo gerado do processo de purificação da água é corriqueiramente descartado em corpos de águas sem nenhum tratamento, violando leis federais e promovendo malefícios para a biota aquática e para a saúde humana. Com isso, o objetivo deste trabalho foi produzir materiais adsorventes a partir do lodo de ETA, utilizando ativação por processo físico (térmico) e químico (hidróxido de potássio – KOH e o ácido fosfórico – H3PO4) e verificar o seu potencial na remoção dos disruptores endócrinos 17β estradiol (E2) e 17α etinilestradiol (EE2) em soluções aquosas sintéticas. Foram produzidos três produtos: MAK, MAP e MAH. Os materiais produzidos foram analisados quanto às características de superfície, grupos funcionais, quanto à composição química e ponto de carga zero. Pelo ensaio de efeito da massa, foi definido a massa de 0,5g de adsorvente para realizar os ensaios subsequentes, a eficiência de remoção foi avaliada em experimento realizado com 0,5g de adsorvente sob agitação constante por 120 min, onde foi possível obter para o EE2 com o MAH (69,89%), MAP (73,02%) e MAK (71,47%), para o E2 obteve-se com MAH (13,75%), MAP (33,55%) e MAK (61,42%). O estudo cinético foi conduzido com tempo de contato máximo de 8 horas e os dados foram ajustados aos modelos de pseudo-primeira e segunda ordem, o tempo de equilíbrio foi definido em 120 min e os dados experimentais se ajustaram ao modelo de pseudo-segunda ordem indicando que a adsorção ocorre por meio da quimissorção. No que se refere as isotermas, os dados experimentais para o EE2 (MAK e MAH) e E2 (MAK, MAP, MAH) obtiveram melhor ajuste ao modelo de Freundlich, entretanto, para o efluente EE2 com adsorvente MAP, os dados obtiveram melhor ajuste ao modelo de Langmuir. Com estes resultados foi possível comprovar a eficácia dos adsorventes produzidos na remoção dos hormônios EE2 e E2 atingindo os objetivos propostos por este trabalho.
Treatment systems face difficulties in purifying water supply and treating urban sewage. Part of these problems is related to synthetic and natural organic compounds generated by industry, agriculture and livestock. Among these compounds, endocrine disruptors stand out. As an aggravating factor, the existing processes in plants are not enough for its separation/removal of these pollutants. In addition to these causes, water treatment plant sludge (WTP) which is the waste generated from the water purification process is routinely discarded in bodies of water without any treatment, violating federal laws and promoting harms for aquatic biota and human health. Thus, the objective of this study was to produce adsorbent materials from ETA sludge, using activation by physical (thermal) and chemical (potassium hydroxide - KOH = MAK and phosphoric acid - H3PO4 = MAP) process, in addition to the MAH that was produced without chemical activation and verify its potential in removing the endocrine disruptors. The materials produced were analyzed for surface characteristics, functional groups, chemical composition, and zero load point. To define the adsorbent mass, a preliminary assay was conducted in which it was proven that the mass of 0.5g of adsorbent was sufficient to perform the subsequent tests, the removal efficiency was evaluated in an experiment carried out under constant agitation for 120 min with the concentration of each adsorbate separately in 100ug/L, in which it was possible to obtain for EE2 with The kinetic study was conducted with a maximum contact time of 8 hours and the data were adjusted to the pseudo-first and second order models, the equilibrium time was set at 120 min, the experimental data adjusted to the pseudo-second order model indicating that adsorption occurred through chemisorption. With regard to isotherms, the experimental data for EE2 (MAK and MAH) and E2 (MAK, MAP, MAH) obtained better fit to Freundlich's model, however, for the EE2 effluent with MAP adsorbent, the data obtained better fit for the Langmuir model. The maximum amount retained in balance for EE2 was: MAH = 4.65ug.g-1 , MAP = 1.81 ug.g.g-1, MAK = 1.78ug.g-1; and for E2 it was: MAH = 2.89ug.g-1 , MAP = 3.98 ug.g-1, MAK = 1.81ug.g-1 . With these results it was possible to prove the effectiveness of the adsorbents produced in the removal of the hormones EE2 and E2 achieving the objectives proposed by this study.
Treatment systems face difficulties in purifying water supply and treating urban sewage. Part of these problems is related to synthetic and natural organic compounds generated by industry, agriculture and livestock. Among these compounds, endocrine disruptors stand out. As an aggravating factor, the existing processes in plants are not enough for its separation/removal of these pollutants. In addition to these causes, water treatment plant sludge (WTP) which is the waste generated from the water purification process is routinely discarded in bodies of water without any treatment, violating federal laws and promoting harms for aquatic biota and human health. Thus, the objective of this study was to produce adsorbent materials from ETA sludge, using activation by physical (thermal) and chemical (potassium hydroxide - KOH = MAK and phosphoric acid - H3PO4 = MAP) process, in addition to the MAH that was produced without chemical activation and verify its potential in removing the endocrine disruptors. The materials produced were analyzed for surface characteristics, functional groups, chemical composition, and zero load point. To define the adsorbent mass, a preliminary assay was conducted in which it was proven that the mass of 0.5g of adsorbent was sufficient to perform the subsequent tests, the removal efficiency was evaluated in an experiment carried out under constant agitation for 120 min with the concentration of each adsorbate separately in 100ug/L, in which it was possible to obtain for EE2 with The kinetic study was conducted with a maximum contact time of 8 hours and the data were adjusted to the pseudo-first and second order models, the equilibrium time was set at 120 min, the experimental data adjusted to the pseudo-second order model indicating that adsorption occurred through chemisorption. With regard to isotherms, the experimental data for EE2 (MAK and MAH) and E2 (MAK, MAP, MAH) obtained better fit to Freundlich's model, however, for the EE2 effluent with MAP adsorbent, the data obtained better fit for the Langmuir model. The maximum amount retained in balance for EE2 was: MAH = 4.65ug.g-1 , MAP = 1.81 ug.g.g-1, MAK = 1.78ug.g-1; and for E2 it was: MAH = 2.89ug.g-1 , MAP = 3.98 ug.g-1, MAK = 1.81ug.g-1 . With these results it was possible to prove the effectiveness of the adsorbents produced in the removal of the hormones EE2 and E2 achieving the objectives proposed by this study.
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Palavras-chave
Adsorbent material, Material Adsorvente, Adsorção, Lodo, 17β Estradiol e 17α Etinilestradio, Adsorption, Sludge