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Preparation of catalysts from biosorbents supported on zeolites
Figueiredo, Hugo Sérgio PitãesTese de doutoramento em Engenharia Química e Biológica ; Heavy metal contamination of aquifers by industrial effluents is a known environmental concern for which a recent effort for the development of treatment/remediation technologies has been conducted. Nevertheless, technologies that allow recuperation/reutilization of the metals are still of limited application. This work presents the development of a clea...
Evaluation of ion exchange-modified Y and ZSM5 zeolites in Cr(VI) biosorption a...
Silva, Bruna; Figueiredo, Hugo; Soares, O. S. G. P.; Pereira, M. F. R.; Figueiredo, J. L.; Lewandowska, A. E.; Bañares, M. A.; Bañares, M. A.The aim of this work was the evaluation of the performance of two zeolites with different structures (FAU and MFI) and acidity properties in the biosorption of Cr(VI) and catalytic oxidation of ethyl acetate. The starting zeolites, Y (FAU) and ZSM5 (MFI), were modified by ion exchange treatments with NaNO3 in order to obtain zeolites with different acidity and sodium content. A biosorption system consisting of ...
Improved biosorption for Cr(VI) reduction and removal by Arthrobacter viscosus ...
Silva, Bruna; Figueiredo, Hugo; Quintelas, C.; Neves, Isabel C.; Tavares, T.The aim of the present work was to optimize the reduction and removal of chromium from aqueous solutions by a biosorption system consisting of a bacteria supported on a zeolite. The system proposed combines the biosorption properties of Arthrobacter viscosus, with the ion exchange capacity of NaY zeolite. Experiments were also performed without the zeolite for comparison purposes. Experimental parameters such a...
Evaluation of ion exchange-modified Y and ZSM5 zeolites in Cr(VI) biosorption a...
Silva, Bruna; Figueiredo, Hugo; Soares, O. S. G. P.; Pereira, M. F. R.; Figueiredo, J. L.; Lewandowska, A. E.; Bañares, M. A.; Neves, Isabel C.The aim of this work is the evaluation of the performance of two zeolites with different structures (FAU and MFI) and acidity properties in the biosorption of Cr(VI) and catalytic oxidation of ethyl acetate. The starting zeolites, Y (FAU) and ZSM5 (MFI), were modified by ion exchange treatments with NaNO3 in order to obtain zeolites with different acidity and sodium content. A biosorption system consisting of a...
Mobility of Cr, Pb, Cd, Cu and Zn in a loamy sand soil : a comparative study
Fonseca, Bruna; Figueiredo, Hugo; Rodrigues, J.; Queiroz, A.; Tavares, M. T.Interest in soil contamination has been growing in recent years due to the ongoing degradation of soil environments. Therefore, the development of remediation techniques and the study of contaminant sorption and migration are areas of intense research. In this study, the authors sought to evaluate the scenario of co-contamination of a loamy sand soil by multiple heavy metals. To that end, the sorption and trans...
The effect of clay treatment on remediation of diethylketone contaminated waste...
Quintelas, C.; Figueiredo, Hugo; Tavares, M. T.The ability of four different clays to adsorb diethylketone was investigated in batch experiments aiming to treat wastewater with low solvent concentrations. The adsorption performance in terms of uptake followed the sequence: vermiculite > sepiolite = kaolinite = bentonite, for all the adsorbent doses tested (from 0.1 to 1.5 g) in 150 mL of ketone solution (800 mg/L). The equilibrium data in the batch systems ...
Optimization of production of extracellular polymeric substances by Arthrobacte...
Quintelas, C.; Silva, Vitor B. da; Silva, Bruna; Figueiredo, Hugo; Tavares, M. T.In this work we aimed to optimize the production of extracellular polymeric substances (EPS) by an Arthrobacter viscosus biofilm supported on 13X zeolite to be used in the biosorption of Cr(VI). The optimization parameters were agitation rate, work volume, pH and glucose concentration. Following the optimization of EPS production, the biofilm was used in the biosorption of hexavalent Cr from liquid solutions. D...
Reutilization of Cr-Y zeolite obtained by biosorption in the catalytic oxidatio...
Silva, Bruna; Figueiredo, Hugo; Santos, V. P.; Pereira, M. F. R.; Figueiredo, J. L.; Lewandowska, A. E.; Bañares, M. A.; Neves, Isabel C.This work aims at the reutilization of a Cr-loaded NaY zeolite obtained by biorecovery of chromium from water as catalyst in the oxidation of volatile organic compounds (VOC). Cr-NaY catalysts were obtained after biosorption of Cr(VI) using a bacterium, Arthrobacter viscosus, supported on the zeolite. The biosorption experiments were conducted at different pH values in the range 1–4. The catalysts were characte...
Mobility of Cr, Pb, Cd, Cu and Zn in a loamy sand soil: a comparative study
Fonseca, Bruna; Figueiredo, Hugo; Rodrigues, Joana; Queiroz, A.M.; Tavares, TeresaInterest in soil contamination has been growing in recent years due to the ongoing degradation of soil environments. Therefore, the development of remediation techniques and the study of contaminant sorption and migration are areas of intense research. In this study, the authors sought to evaluate the scenario of co-contamination of a loamy sand soil by multiple heavy metals. To that end, the sorption and trans...
Effect of the supporting zeolite structure on Cr biosorption : performance of a...
Figueiredo, Hugo; Silva, Bruna; Quintelas, C.; Neves, Isabel C.; Tavares, M. T.This work presents a study on the applicability of a zeolite-biomass system to the entrapment of metallic ions, starting from Cr(VI) solutions up to 100 mgCr/L, in batch processes. The effect of the zeolitic support on the overall system performance was evaluated comparing two large pore zeolitic structures which differ in chemical composition and ion-exchange capacity: Faujasite (HY and NaY) and Mordenite (HMO...
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