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Bioremoval of diethylketone by the synergistic combination of microorganisms an...
Quintelas, C.; Costa, Filomena; Tavares, T.The performance of two bacteria, Arthrobacter viscosus and Streptococcus equisimilis, and the effect of the interaction of these bacteria with four different clays on the retention of diethylketone were investigated in batch experiments. The uptake, the removal percentages and the kinetics of the processes were determined. S. equisimilis,by itself, had the best performance in terms of removal percentage, for al...
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...
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...
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...
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...
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...
Removal of organic compounds by a biofilm supported on GAC : modelling of batch...
Quintelas, C.; Silva, Bruna; Figueiredo, Hugo; Tavares, M. T.The performance of a biofilm of Arthrobacter viscosus supported on granular activated carbon on the retention of organic compounds was evaluated. The presence of functional groups on the cell wall surface of the biomass that may interact with the organic compounds was confirmed by Fourier transform infrared spectroscopy, to assess the applicability of this system to the removal of those compounds. The batch ass...
Immobilization of chromium complexes in zeolite Y obtained from biosorbents : s...
Figueiredo, Hugo; Silva, Bruna; Quintelas, C.; Raposo, M. Manuela M.; Parpot, Pier; Fonseca, A. Maurício C.; Lewandowska, A. E.; Bañares, M. A.The goal of this study is the preparation of new heterogeneous catalytic materials to be used in oxidation reactions under mild conditions through the valuation of heavy metals in wastewater. The samples used in the immobilization of chromium complexes were prepared from a dichromate solution of 100 mgCr L−1. The zeolite CrNaY was prepared from a robust biosorption system consisting of a bacterial biofilm, Arth...
Biosorption of hexavalent chromium based on modified Y zeolites obtained by alk...
Figueiredo, Hugo; Silva, Bruna; Quintelas, C.; Pereira, M. F. R.; Neves, Isabel C.; Tavares, M. T.The structural modification of external surface of NaY was investigated in order to enhance efficient biosorption systems consisting of a bacterial biofilm, Arthrobacter viscosus, supported on that zeolite, for removing hexavalent chromium from aqueous solutions. The supported bacterial biofilm reduces Cr(VI) to Cr(III) and this cation is then retained in the zeolite by ion exchange. NaY zeolite was modified by...
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