Abstract:The search for an efficient and low cost adsorbent for the treatment of wastewaters containing dyes motivated this work. The efficiency of the adsorbent from agro-waste, potato peel (Solanum tuberosum L.), was tested using the cationic dye methylene blue as adsorbate. Adsorption studies were conducted in batch and fixed-bed column systems. The parameters evaluated in batch system were: point of zero charge (PZC), kinetics and adsorption isotherm, applying the theoretical models of Langmuir and Freundlich. With fixed-bed column it was possible to obtain saturation and reuse curves of the adsorbent and recovery of the dye. The Langmuir isotherm model was the best fit to the experimental data, with a maximum amount adsorbed (q max ) of 48.7 mg g -¹.The maximum adsorption capacity of the column was 35.83 mg g -¹. It was also verified the possibility of recovery the dye using HCl solution and reusing the adsorbent after this process.Keywords: Adsorption; dye; agro-waste.
ResumoA busca de um adsorvente eficiente e de baixo custo para o tratamento de resíduos contendo corantes motivou a realização deste trabalho. A eficiência do adsorvente proveniente do agro resíduo de casca de batatas (Solanum tuberosum L.) foi testada utilizando o corante catiônico azul de metileno como adsorvato. Os estudos de adsorção foram conduzidos em sistema em batelada e coluna de leito fixo. Os parâmetros avaliados em sistema em batelada foram: ponto de carga zero (PCZ), cinética e isoterma de adsorção, aplicando os modelos teóricos de Langmuir e Freundlich. Os estudos com coluna de leito fixo possibilitaram a obtenção de curvas de saturação e reutilização do adsorvente e recuperação do corante. O modelo de isoterma de Langmuir foi o que melhor se ajustou aos dados experimentais, apresentando um valor de quantidade máxima adsorvida (q máx ) de 48,7 mg g -¹. A capacidade máxima de adsorção na coluna foi de 35,83 mg g -¹. Foi verificado ainda a possibilidade de recuperação do corante utilizando solução de HCl e a reutilização do adsorvente após este processo.Palavras-chave: Adsorção; corante; agro resíduo.
This study, was to evaluate the acaricidal effect of the essential oil (EO) and fractions (FR) obtained from Laurus nobilis leaves on Rhipicephalus (Boophilus) microplus. Eight fractions were obtained, however FR1: sabinene (37.83%), β-pinene (13.50%), 1,8-cineole (12.66%), α-pinene (12.56%) and FR8: α-terpineol (79.19%) were highlighted as to the larvicidal potential when submitted by Larval Packet Test. The EO was tested by the Adult Immersion Test, at concentrations of 200.00; 100.00 and 50.00 µL/mL caused mortality of engorged females, egg mass reduction and hatching inhibition. Two fractions are shown to be efficient in controlling larvae FR8 (LC 50 =0.13 µL/mL, LC 99 =0.51 µL/mL) and FR1 (LC 50 =0.20 µL/mL, LC 99 =0.56 µL/mL). The fractionation of EO was determinant to elucidate which compounds were responsible for the larvicidal potential. This study opens new perspectives to direct new bioassays with the compounds obtained in the fractionation, since they present high potential on the cattle tick larvae.
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