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Removal of Ni(II) from aqueous solutions by an Arthrobacter viscosus biofilm su...
Quintelas, C.; Pereira, Ricardo; Kaplan, Ecem; Tavares, M. T.This study discusses the retention of Ni(II) by Arthrobacter viscosus supported on zeolite 13 X in batch mode and in continuous mode, at laboratory scale and at pilot scale. The maximum adsorption capacities of 28.37, 20.21 and 11.13 mg/g were recorded for lab scale batch, for continuous lab scale minicolumns and for pilot scale bioreactors, respectively. The Sips isotherm and pseudo second order kinetics descr...
Application of zeolite-Arthrobacter viscosus system for the removal of heavy me...
Rosales, E.; Pazos, M.; Sanromán, M. A.; Tavares, M. T.A hybrid system combining the ion-exchange properties of a NaY zeolite and the characteristics of the bacterium Arthrobacter viscosus was investigated to treat polluted effluents with dye and toxic metals. In this study, the dye and the metal ion employed were a thiazine dye, Azure B, and chromium (VI), respectively. Initially, the removal of dye by the zeolite was tested. The analysis of dye equilibrium isothe...
Kinetics of biodegradation of diethylketone by Arthrobacter viscosus
Costa, Filomena; Quintelas, C.; Tavares, M. T.The performance of an Arthrobacter viscosus culture to remove diethylketone from aqueous solutions was evaluated. The effect of initial concentration of diethylketone on the growth of the bacteria was evaluated for the range of concentration between 0 and 4.8 g/l, aiming to evaluate a possible toxicological effect. The maximum specific growth rate achieved is 0.221 h-1 at 1.6 g/l of initial diethylketone concen...
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...
Biosorption of heavy metal and dyes : a promising technology leather wastewater...
Rosales, E.; Pazos, M.; Sanromán, M. A.; Tavares, M. T.The presence of dyes and heavy metals is usual in industrial processes like chrome tanning in tannery industry and their removal may be an environmental problem. Different techniques were developed and applied for the treatment of dyes and heavy metals in effluents. Among them, adsorption showed to be an economic, simple operation and an effective technique. Zeolites have a strong affinity for cations of transi...
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...
Chromium (VI) ion adsorption features of chitosan film and its chitosan/zeolite...
Batista, Anabelle C. L.; Villanueva, Emílio R.; Amorim, Rosa Valéria S.; Tavares, M. T.; Takaki, G. M. CamposThis research evaluated the importance of the adsorption properties of chitosan a chitosan/zeolite conjugate film for the removal of Cr(VI) ions from solutions in the 5–260 mg/L concentration range, when the pH was adjusted to 4.0 and 6.0. The uptake capacities of the films formed by chitosan and by the chitosan/zeolite conjugate were calculated by mass balance. The equilibrium isotherms were fitted to the Lang...
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