52 research outputs found
The influence of electrodialytic remediation on dioxin (PCDD/PCDF) levels in fly ash and air pollution control residues
Fly ash and Air Pollution Control (APC) residues collected from three municipal solid waste incinerators
in Denmark and Greenland were treated by electrodialytic remediation at pilot scale for 8e10 h. This
work presents for the first time the effect of electrodialytic treatment on polychlorinated dibenzo-pdioxins (PCDD) and polychlorinated dibenzofurans (PCDF), and how these levels impact on the valorization options for fly ash and APC residue.
PCDD/PCDF levels in the original residues ranged between 4.85 and 197 ng g1
, being higher for the
electrostatic precipitator fly ash. The toxic equivalent (TEQ) varied ten fold, ranging 0.18e2.0 ng g1 ITEQ, with penta and hexa-homologs being most significant for toxicity.
After the electrodialytic treatment PCDD/PCDF levels increased in the residues (between 1.4 and 2.0
times). This does not mean PCDD/PCDF were synthesized, but else that soluble materials dissolve, leaving
behind the non-water soluble compounds, such as PCDD/PCDF. According to the Basel Convention, PCDD/
PCDF levels in these materials is low (<15 mg WHO-TEQ kg1
) and the fly ash and APC residue could
eventually be valorized, for instance as construction material, provided end-of-waste criteria are set and
that a risk assessment of individual options is carried out, including the end-of-life stage when the
materials become waste again.info:eu-repo/semantics/publishedVersio
Electrochemical desalination of historic Portuguese tiles:Removal of chlorides, nitrates and sulfates
Soluble salts cause severe decay of historic Portuguese tiles. Treatment options for removal of the salts
to stop the decay are few. The present paper deals with development of a method for electrochemical
desalination, where an electric DC field is applied to the tiles. Laboratory experiments were conducted
with single 18th century tiles from Palácio Centeno, Lisbon, Portugal. Large parts of the glaze and parts
of the biscuit were lost from salt decay. The major aim of the investigation was to see if the method
could offer sufficient salt removal in the biscuit and in the interface between biscuit and glaze, where salt
crystals were clearly identified by SEM-EDX before desalination. The concentrations of chloride and especially nitrate were very high in the tiles (around 280 mmol Cl−/kg and 450 mmol NO3
−/kg respectively).
Both anions were successfully removed to below 6 mmol/kg during the electrochemical treatment. The
removal rate was similar for the two anions so the chloride concentration reached the lowest concentration level first. At this point the electric resistance increased, but the removal of nitrate continued
unaffected till similar low concentration. The sulfate concentration was initially very low, but nevertheless, sulfate removal started at the point where chloride and nitrate concentrations were very low in
the tiles. Investigating the interface between biscuit and glaze after the treatment showed no signs of
crystallized salts, so also in this important point, the desalination was successful. Based on the obtained
results an important step is taken towards development of an electrochemical technique for desalination
of tile panels.info:eu-repo/semantics/publishedVersio
Electrodialytic upgrading of three different municipal solid waste incineration residue types with focus on Cr, Pb, Zn, Mn, Mo, Sb, Se, V, Cl and SO<sub>4</sub>
Handling of air pollution control (APC) residues from municipal solid waste incineration (MSWI) is a
challenge due to its toxicity and high leaching of toxic elements and salts. Electrodialysis (ED) of the
material has shown potential for reduction of leaching of toxic elements and salts to produce a material
feasible for substitution of cement in mortar. In this work results of 23 pilot-scale experiments (5–8 kg
APC residue each) in electrodialysis stack designed to investigate the leaching properties as a function of
time and current density for APC residue from semi-dry and wet flue-gas cleaning systems, as well as
MSWI fly ash without flue-gas cleaning products are reported. Significant leaching reduction of the
critical elements Pb, Zn and Cl was obtained. The final leaching, however, depended mostly on the initial
leaching, thus as leaching from fly ash and residue of wet flue-gas cleaning was lower before treatment
compared to residues from semidry flue-gas cleaning, both Pb and Zn leaching could be reduced to lower
levels in those materials, and they therefore appear more suitable for use in construction materials. The
leaching reduction of Zn and to some degree Pb decreased with longer retention times and higher current
densities. Cr and SO4 leaching increased during ED treatment, with lower increase at higher current.
Washing or carbonation in combination with ED significantly reduced leaching of Pb and Zn from semidry
residue. An indication of a similar effect to carbonation by simultaneous aeration with ED was observed
and should be investigated further. While Mn and Mo leaching did not, Se, V and Sb leaching exceeded
threshold values in semidry residue. The leaching of V seemed to increase while Se and Sb remained more
or less constant during ED treatment.info:eu-repo/semantics/publishedVersio
Numerical prediction of diffusion and electric field-induced iron nanoparticle transport
Zero valent iron nanoparticles (nZVI) are considered very promising for the remediation of contaminated soils and groundwaters. However, an important issue related to their limited mobility remains unsolved. Direct current can be used to enhance the nanoparticles transport, based on the same principles of electrokinetic remediation. In this work, a generalized physicochemical model was developed and solved numerically to describe the nZVI transport through porous media under electric field, and with different electrolytes (with different ionic strengths). The model consists of the Nernst–Planck coupled system of equations, which accounts for the mass balance of ionic species in a fluid medium, when both the diffusion and electromigration of the ions are considered. The diffusion and electrophoretic transport of the negatively charged nZVI particles were also considered in the system. The contribution of electroosmotic flow to the overall mass transport was included in the model for all cases. The nZVI effective mobility values in the porous medium are very low (10−7–10−4 cm2 V−1 s−1), due to the counterbalance between the positive electroosmotic flow and the electrophoretic transport of the negatively charged nanoparticles. The higher the nZVI concentration is in the matrix, the higher the aggregation; therefore, low concentration of nZVI suspensions must be used for successful field application.This work has been funded by the research grant SFRH/BD/76070/2011, by project PTDC/AGR-AAM/101643/2008 NanoDC under Portuguese National funds through “Fundação para a Ciência e a Tecnologia” and by FP7-PEOPLE-IRSES-2010-269289-ELECTROACROSS. The Department of Civil and Environmental Engineering at Lehigh University is acknowledged for the funding of equipment development, testing and analysis of the nZVI transport experiments
Mercury levels in fly ash and APC residue from municipal solid waste incineration before and after electrodialytic remediation
Fly ash (FA) and Air Pollution Control (APC) residues collected from three municipal solid waste incinerators (MSWI) in Denmark and Greenland were treated by electrodialytic remediation at pilot scale for 8 to 10 h. The original residues and the treated material were analysed for mercury (Hg) in order to assess the influence of the electrodialytic treatment on the concentrations of this element. Mercury levels varied with the MSWI residue, ranging from 0.41 mg kg1 in FA sample from electrostatic precipitator (ESP) to 8.38 mg kg1 in MSWI residues from a semi-dry system with lime and activated carbon. Two distinct behaviours were observed for mercury as a result of the electrodialytic treatment. This element became enriched in the MSWI residues from the semi-dry system with activated carbon, whereas it decreased in ESP's and cyclone's FA. This work presents for the first time information about the effect of electrodialytic treatment on mercury levels and discusses the valorisation options for these MSWI residues. © 2016 WIT Press
Assessment of combined electro–nanoremediation of molinate contaminated soil
Molinate is a pesticide widely used, both in space and time, for weed control in rice paddies. Due to its water
solubility and affinity to organic matter, it is a contaminant of concern in ground and surface waters, soils and
sediments. Previous works have showed that molinate can be removed from soils through electrokinetic (EK)
remediation.
In this work, molinate degradation by zero valent iron nanoparticles (nZVI) was tested in soils for the first time.
Soil is a highly complex matrix, and pollutant partitioning between soil and water and its degradation rates in
different matrices is quite challenging. A system combining nZVI and EK was also set up in order to study the
nanoparticles and molinate transport, as well as molinate degradation.
Results showed that molinate could be degraded by nZVI in soils, even though the process is more time
demanding and degradation percentages are lower than in an aqueous solution. This shows the importance
of testing contaminant degradation, not only in aqueous solutions, but also in the soil-sorbed fraction. It was
also found that soil type was the most significant factor influencing iron and molinate transport. The main
advantage of the simultaneous use of both methods is the molinate degradation instead of its accumulation
in the catholyte.info:eu-repo/semantics/publishedVersio
Portal de Busca Integrada do SIBiUSP: metodologia de implantação
Relata o estudo, a instalação e implantação de ferramenta de descoberta e entrega do Portal de Busca Integrada, para o Sistema Integrado de Bibliotecas da Universidade de São Paulo (SIBiUSP). Esta nova interface denominada Portal de Busca Integrada possibilita uma nova experiência de pesquisa científica ao usuário final pela recuperação de literatura em diferentes fontes de informação
Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study
Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazili an centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome83289298CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSSem informaçãoSem informação2006/60402-1; 2010/51547-1; 2013/01476-9; 2014/06570-6; 2009/50575-4; 2010/51546-5; 2012/21942-116/2551-0000482-
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A social and ecological assessment of tropical land uses at multiple scales: the Sustainable Amazon Network
Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazonia Sustentavel, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far.Keywords: Social–ecological systems, Tropical forests, Land use, Interdisciplinary research, Sustainability, Trade-off
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