115 documents found, page 1 of 12
Comportamento geoquímico de alguns elementos vestigiais na envolvente das Minas...
Tavares, M. T.; Abreu, M. M.; Vairinho, M. M.; Sousa, A. J.; Quental, L.A actividade mineira em S. Domingos cessou há mais de quarenta anos, porém, ainda hoje, o antigo parque mineiro é fonte de dispersão de elementos vestigiais potencialmente contaminantes que se acumulam nos sedimentos e nos solos a juzante da zona de exploração. O presente trabalho teve como objectivo a avaliação da contaminação dos solos e sedimentos na área de confluência das ribeiras de S. Domingos e do Moste...
Enhanced selective metal adsorption on optimised agroforestry waste mixtures
Rosales, E.; Ferreira, Laura; Sanromán, M. A.; Tavares, M. T.; Pazos, M.The aim of this work is to ascertain the potentials of different agroforestry wastes to be used as biosorbents in the removal of a mixture of heavy metals. Fern (FE), rice husk (RI) and oak leaves (OA) presented the best removal percentages for Cu(II) and Ni(II), Mn(II) and Zn(II) and Cr(VI), respectively. The performance of a mixture of these three biosorbents was evaluated, and an improvement of 10% in the ov...
Biodegradation of diethylketone by Penicillium sp. and Alternaria sp.: a compar...
Costa, Filomena Natália Araújo; Neto, Marta Martins; Nicolau, Ana; Tavares, M. T.Two contaminating fungi were isolated from a bioreactor containing diethylketone and Streptococcus equisimilis, subsequently characterized at molecular level and identified as belonging to the Alternaria and Penicillium genera. The ability of these fungi to biodegrade DEK is evaluated. The kinetic parameters are estimated using four growth kinetic models for biodegradation of organic compounds available in lite...
Experimental analysis and mathematical prediction of Cd(II) removal by biosorpt...
Hlihor, R. M.; Diaconu, M.; Leon, Florin; Curteanu, Silvia; Tavares, M. T.; Gavrilescu, M.We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R2 > 0.99. The value of the mean free energy of adsorption, E, is less ...
Biosorption of metals – from the basics to high value catalysts production
Tavares, M. T.; Quintelas, C.Increasing awareness of environmental pollution with heavy metals and its long-term and xenobiotic effects has instigated growing research and development efforts towards pollution abatement. The application of different biological materials in the removal and recovery of metals from wastewater has been reported in numerous studies.1–5 Usually, the mechanisms of biosorption are defined as being metabolic indepe...
Heterogeneous electro-Fenton treatment: preparation, characterization and perfo...
Iglesias, O.; Fernández de Dios, M. A.; Tavares, M. T.; Sanromán, M. A.In this work the preparation, characterization and performance of Y-zeolite as catalyst for electro-Fenton treatment of pesticides was carried out. Initially iron supported Y-zeolite (Fe-Y) was prepared and evaluated for the degradation of imidacloprid and chlorpyrifos. Kinetics studies determined that the pesticides removal followed a pseudo-first-order kinetic model. However, the reusability of this catalyst ...
Mechanisms of Cr(III) biosorption onto residual brewer's yeast
Ferraz, A. I.; Costa, Filomena; Tavares, M. T.; Teixeira, J. A.The knowledge and understanding of metal-biomass interactions is crucial to develop and maximize biosorption processes potential to the concentration, removal and recovery of heavy metals from dilute solutions, as well as to define strategies to regenerate and reuse biosorbent in multiple cycles (Ahluwalia and Goyal, 2007; Volesky, 2001). It also turns possible biosorption optimization at a molecular level, inc...
Removal of Di-(2-ethylhexyl)phthalate (DEHP) from water using a LECA-Pseudomona...
Rosales, E.; Cobas, M.; Tavares, M. T.; Sanromán, M. A.; Pazos, M.The removal and biodegradation of an organic toxic pollutant, di-(2-ethylhexyl) phthalate (DEHP), has been investigated. Initially, a screening of different degrading bacteria has been developed and Pseudomonas putida showed the highest degradation ability. This bacterium was immobilised in an inert support, light expanded clay aggregate (LECA). After the biofilm formation on the LECA, the degradation of DEHP w...
An approach to the metabolic degradation of diethylketone (DEK) by Streptococcu...
Costa, Filomena; Quintelas, C.; Tavares, M. T.Abstract The degradation of diethylketone by Streptococcus equisimilis was evaluated. The toxicity of diethylketone was assessed evaluating the growth of the bacteria for the range of diethylketone concentration between 0 and 6.4 g L−1. The maximum specific growth rate achieved is 0.555 h−1 at 3.2 g L−1 of initial diethylketone concentration, followed by a slight decrease, suggesting that higher concentrations ...
Biodegradation of diethylketone by two fungi
Costa, Filomena; Neto, Marta Martins; Nicolau, Ana; Tavares, M. T.Two morphologically different fungi (one green and one white) from contaminated bioreactors with an aqueous solution of diethylketone and Streptococcus equisimilis were isolated and characterized at molecular level by sequencing the amplified ITS region. The ITS region sequence showed 99% match with Alternaria genera for the green fungi and 99% match with the Penicillium genera for the white fungi. The performa...