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The removal of the hazardous Hg2+ from aqueous solutions was studied by ion exchange using titanosilicate in sodium form (Na-ETS-4). Isothermal batch experiments at fixed pH were performed to measure equilibrium and kinetic data, considering two very distinct situations to assess the influence of competition effects: (i) the counter ions initially in solution are Na+ and Hg2+ (both are exchangeable); (ii) the initial counter ions in solution are tetrapropylammonium (TPA+) and Hg2+ (only Hg2+ is exchangeable, since TPA+ is larger than the ETS-4 micropores). The results confirmed that ETS-4 is highly selective for Hg2+, with more than 90% of the mercury being exchanged from the fluid phase. The final equilibrium attained under the presence of TPA+ or Na+ in solution was very similar, however, the Hg2+/Na+/ETS-4 system in the presence of Na+ required more 100 h to reach equilibrium than in the presence of TPA+. The Hg2+/Na+/ETS-4 system was modelled and analyzed in terms of equilibrium (mass action law) and mass transfer (Maxwell–Stefan (MS) formalism). Concerning equilibrium, no major deviations from ideality were found in the range of studied concentrations. On the other hand, the MS based model described successfully (average deviation of 5.81%) all kinetic curves of mercury removal.
Simão P. Cardoso; Tiago L. Faria; Eduarda Pereira; Inês Portugal; Cláudia B. Lopes; Carlos M. Silva. Mercury Removal from Aqueous Solution Using ETS-4 in the Presence of Cations of Distinct Sizes. Materials 2020, 14, 11 .
AMA StyleSimão P. Cardoso, Tiago L. Faria, Eduarda Pereira, Inês Portugal, Cláudia B. Lopes, Carlos M. Silva. Mercury Removal from Aqueous Solution Using ETS-4 in the Presence of Cations of Distinct Sizes. Materials. 2020; 14 (1):11.
Chicago/Turabian StyleSimão P. Cardoso; Tiago L. Faria; Eduarda Pereira; Inês Portugal; Cláudia B. Lopes; Carlos M. Silva. 2020. "Mercury Removal from Aqueous Solution Using ETS-4 in the Presence of Cations of Distinct Sizes." Materials 14, no. 1: 11.
Humans are typically exposed to environmental contaminants’ mixtures that result in different toxicity than exposure to the individual counterparts. Yet, the toxicology of chemical mixtures has been overlooked. This work aims at assessing and comparing viability and cell cycle of A549 cells after exposure to single and binary mixtures of: titanium dioxide nanoparticles (TiO2NP) 0.75–75 mg/L; cerium oxide nanoparticles (CeO2NP) 0.75–10 μg/L; arsenic (As) 0.75–2.5 mg/L; and mercury (Hg) 5–100 mg/L. Viability was assessed through water-soluble tetrazolium (WST-1) and thiazolyl blue tetrazolium bromide (MTT) (24 h exposure) and clonogenic (seven-day exposure) assays. Cell cycle alterations were explored by flow cytometry. Viability was affected in a dose- and time-dependent manner. Prolonged exposure caused inhibition of cell proliferation even at low concentrations. Cell-cycle progression was affected by TiO2NP 75 mg/L, and As 0.75 and 2.5 μg/L, increasing the cell proportion at G0/G1 phase. Combined exposure of TiO2NP or CeO2NP mitigated As adverse effects, increasing the cell surviving factor, but cell cycle alterations were still observed. Only CeO2NP co-exposure reduced Hg toxicity, translated in a decrease of cells in Sub-G1. Toxicity was diminished for both NPs co-exposure compared to its toxicity alone, but a marked toxicity for the highest concentrations was observed for longer exposures. These findings prove that joint toxicity of contaminants must not be disregarded.
Fernanda Rosário; Maria João Bessa; Fátima Brandão; Carla Costa; Cláudia B. Lopes; Ana C. Estrada; Daniela S. Tavares; João Paulo Teixeira; Ana Teresa Reis. Unravelling the Potential Cytotoxic Effects of Metal Oxide Nanoparticles and Metal(Loid) Mixtures on A549 Human Cell Line. Nanomaterials 2020, 10, 447 .
AMA StyleFernanda Rosário, Maria João Bessa, Fátima Brandão, Carla Costa, Cláudia B. Lopes, Ana C. Estrada, Daniela S. Tavares, João Paulo Teixeira, Ana Teresa Reis. Unravelling the Potential Cytotoxic Effects of Metal Oxide Nanoparticles and Metal(Loid) Mixtures on A549 Human Cell Line. Nanomaterials. 2020; 10 (3):447.
Chicago/Turabian StyleFernanda Rosário; Maria João Bessa; Fátima Brandão; Carla Costa; Cláudia B. Lopes; Ana C. Estrada; Daniela S. Tavares; João Paulo Teixeira; Ana Teresa Reis. 2020. "Unravelling the Potential Cytotoxic Effects of Metal Oxide Nanoparticles and Metal(Loid) Mixtures on A549 Human Cell Line." Nanomaterials 10, no. 3: 447.
Water is an essential resource on Earth and the maintenance of its quality led to the incentive of water reuse programmes. Among the most relevant contaminants, mercury is recognized for its toxicity and biomagnifications along the food chain, reason why its removal from aqueous solutions was studied in this essay using two microporous materials for the first time. The ability of a niobium silicate, called AM-11 (Aveiro-Manchester No 11), and of a vanadium silicate, AM-14 (Aveiro-Manchester No 14), were assessed under batch conditions, at fixed temperature and pH. These microporous materials were synthesized and characterized by SEM, PXRD, ICP-OES, TGA and elemental analysis. Because of their excellent ion exchange properties, equilibrium and kinetics assays were performed using only a few mg dm−3 of material. The most relevant two- and three-parameter isotherms were used to fit the experimental data. Langmuir isotherm adjusted better the AM-11 data (deviation of 3.58 %, Radj2=0.980, AIC=52.8), predicting a maximum uptake of 161 mg g−1, while the AM-14 data were better fitted by the Temkin model (deviation of 3.92 %, Radj2=0.985, AIC=54.2). The kinetic study was performed using Elovich, pseudo-first order and pseudo-second order models. The pseudo–second order and Elovich equations provided the best fits for both materials. The Elovich equation achieved a better correlation in the initial branch while the pseudo-second order expression was more efficient for the horizontal branch. The intraparticle diffusivities of counter ions were also assessed using a kinetic model based on the Nernst-Plank equations. Performance of these two microporous materials to remove mercury has been compared with other sorbents, highlighting their potential as ion exchangers.
Elaine Fabre; Arany Rocha; Simão P. Cardoso; Paula Brandão; Carlos Vale; Cláudia B. Lopes; Eduarda Pereira; Carlos M. Silva. Purification of mercury-contaminated water using new AM-11 and AM-14 microporous silicates. Separation and Purification Technology 2019, 239, 116438 .
AMA StyleElaine Fabre, Arany Rocha, Simão P. Cardoso, Paula Brandão, Carlos Vale, Cláudia B. Lopes, Eduarda Pereira, Carlos M. Silva. Purification of mercury-contaminated water using new AM-11 and AM-14 microporous silicates. Separation and Purification Technology. 2019; 239 ():116438.
Chicago/Turabian StyleElaine Fabre; Arany Rocha; Simão P. Cardoso; Paula Brandão; Carlos Vale; Cláudia B. Lopes; Eduarda Pereira; Carlos M. Silva. 2019. "Purification of mercury-contaminated water using new AM-11 and AM-14 microporous silicates." Separation and Purification Technology 239, no. : 116438.
The use of banana peels as biosorbent for mercury sorption from different aqueous solutions was investigated in this work. The impact of the operating conditions, such as biosorbent dosage, contact time and ionic strength was evaluated for realistic initial Hg(II) concentrations of 50 μg dm−3. Biosorbent dosage and contact time showed more influence on Hg(II) removal than ionic strength, and their increase led to improve Hg(II) uptake achieving final concentrations with drinking water quality. The kinetic behaviour of the sorption process was assessed through the reaction-based models of pseudo-first order, pseudo-second order and Elovich, being the last two more appropriated to describe the process. The equilibrium study showed that Freundlich isotherm provided the best fit to the experimental results (R2 = 0.991), which may suggest a multilayer mechanism at biosorbent surface, and the sorption capacity of banana peels obtained from Langmuir isotherm was 0.75 mg g−1. The ability of banana peels to sorb Hg(II) was also examined under real waters, like seawater and a wastewater, which confirmed the feasibility of the biosorbent. Additionally, a counter-current two-stages unit has been proposed for the application of banana peels as biosorbent in water treatments for mercury removal.
Elaine Fabre; Cláudia B. Lopes; Carlos Vale; Eduarda Pereira; Carlos M. Silva. Valuation of banana peels as an effective biosorbent for mercury removal under low environmental concentrations. Science of The Total Environment 2019, 709, 135883 .
AMA StyleElaine Fabre, Cláudia B. Lopes, Carlos Vale, Eduarda Pereira, Carlos M. Silva. Valuation of banana peels as an effective biosorbent for mercury removal under low environmental concentrations. Science of The Total Environment. 2019; 709 ():135883.
Chicago/Turabian StyleElaine Fabre; Cláudia B. Lopes; Carlos Vale; Eduarda Pereira; Carlos M. Silva. 2019. "Valuation of banana peels as an effective biosorbent for mercury removal under low environmental concentrations." Science of The Total Environment 709, no. : 135883.
The need to overcome logistic and ethical limitations of in vivo nanotoxicity evaluation in marine organisms is essential, mostly when dealing with fish. It is well established that medium/solvent conditions affect dispersion and agglomeration of nanoparticles (NPs), which represents a constraint towards a solid and realistic toxicity appraisal. In this way the pros and cons of an ex vivo approach, using a simplified exposure medium (seawater) and addressing gills histopathology, were explored. The nanotoxic potential of environmentally realistic concentrations of titanium dioxide NPs (TiO2 NPs) was also assessed, disclosing the morpho-functional effects on the gills and the possible uptake/elimination processes. Excised gills of the Senegalese sole (Solea senegalensis) were directly exposed in artificial seawater to 20 and 200 μg L−1 TiO2 NPs, for 2 h and 4 h. Semi-quantitative and quantitative histological analyses were applied. The normal morphology of the gill’s epithelia was only slightly altered in the control, reflecting protective mechanisms against the artificiality of the experimental conditions, which, together with the absence of differences in the global histopathological index (Ih), corroborated that the gill’s morpho-functional features were not compromised, thereby validating the proposed ex vivo approach. TiO2 NPs induced moderate severity and dissemination of histopathological lesions. After 2 h, a series of compensatory mechanisms occurred in NP treatments, implying an efficient response of the innate defense system (increasing number of goblet cells) and effective osmoregulatory ability (chloride cells proliferation). After 4 h, gills revealed signs of recovery (normalization of the number of chloride and goblet cells; similar Ih), highlighting the tissue viability and effective elimination and/or neutralization of NPs. The uptake of the TiO2 NPs seemed to be favored by the higher particle sizes. Overall, the proposed approach emerged as a high-throughput, reliable, accurate and ethically commendable methodology for nanotoxicity assessment in marine fish.
C.L. Mieiro; Marta Martins; M. da Silva; João Pedro Coelho; Cláudia Lopes; A. Alves da Silva; Joana Alves; E. Pereira; M. Pardal; Maria Helena Costa; Mário Pacheco. Advances on assessing nanotoxicity in marine fish – the pros and cons of combining an ex vivo approach and histopathological analysis in gills. Aquatic Toxicology 2019, 217, 105322 .
AMA StyleC.L. Mieiro, Marta Martins, M. da Silva, João Pedro Coelho, Cláudia Lopes, A. Alves da Silva, Joana Alves, E. Pereira, M. Pardal, Maria Helena Costa, Mário Pacheco. Advances on assessing nanotoxicity in marine fish – the pros and cons of combining an ex vivo approach and histopathological analysis in gills. Aquatic Toxicology. 2019; 217 ():105322.
Chicago/Turabian StyleC.L. Mieiro; Marta Martins; M. da Silva; João Pedro Coelho; Cláudia Lopes; A. Alves da Silva; Joana Alves; E. Pereira; M. Pardal; Maria Helena Costa; Mário Pacheco. 2019. "Advances on assessing nanotoxicity in marine fish – the pros and cons of combining an ex vivo approach and histopathological analysis in gills." Aquatic Toxicology 217, no. : 105322.
Technology critical elements (TCE) are considered the vitamins of nowadays technology. Factors such as high demand, limited sources and geopolitical pressures, mining exploitation and its negative impact, point these elements as new emerging contaminants and highlight the importance for removal and recycling TCE from contaminated waters. This paper reports the synthesis, characterization and application of hybrid nanostructures to remove and recover lanthanides from water, promoting the recycling of these high value elements. The nanocomposite combines the interesting properties of graphite nanoplatelets, with the magnetic properties of magnetite, and exhibits good sorption properties towards La(III), Eu(III) and Tb(III). The sorption process was very sensitive to solution pH, evidencing that electrostatic interactions are the main binding mechanism involved. Removal efficiencies up to 80% were achieved at pH 8, using only 50 mg/L of nanocomposite. In ternary solution, occurred a preferential removal of Eu(III) and Tb(III). The equilibrium evidenced a rare but interesting behaviour, and as a proof-of-concept the recoveries and reutilization rates, at consecutive cycles, highlight the recyclability of the composite without loss of efficiency. This study evidences that surface charge and the number of active sites of the composite controls the removal process, providing new insights on the interactions between lanthanoids and magnetic-graphite-nanoplatelets.
Elisabete Luís Afonso; Lina Carvalho; Sara Fateixa; Carlos De Oliveira Amorim; Vitor Amaral; Carlos Vale; Eduarda Pereira; Carlos Manuel Silva; Tito Trindade; Cláudia Batista Lopes. Can contaminated waters or wastewater be alternative sources for technology-critical elements? The case of removal and recovery of lanthanides. Journal of Hazardous Materials 2019, 380, 120845 .
AMA StyleElisabete Luís Afonso, Lina Carvalho, Sara Fateixa, Carlos De Oliveira Amorim, Vitor Amaral, Carlos Vale, Eduarda Pereira, Carlos Manuel Silva, Tito Trindade, Cláudia Batista Lopes. Can contaminated waters or wastewater be alternative sources for technology-critical elements? The case of removal and recovery of lanthanides. Journal of Hazardous Materials. 2019; 380 ():120845.
Chicago/Turabian StyleElisabete Luís Afonso; Lina Carvalho; Sara Fateixa; Carlos De Oliveira Amorim; Vitor Amaral; Carlos Vale; Eduarda Pereira; Carlos Manuel Silva; Tito Trindade; Cláudia Batista Lopes. 2019. "Can contaminated waters or wastewater be alternative sources for technology-critical elements? The case of removal and recovery of lanthanides." Journal of Hazardous Materials 380, no. : 120845.
Modern societies depend strongly on electronic and electric equipment (EEE) which has a side effect result on the large production of electronic wastes (e-waste). This has been regarded as a worldwide issue, because of its environmental impact—namely due to non-adequate treatment and storage limitations. In particular, EEE is dependent on the availability of rare earth elements (REEs), considered as the “vitamins” of modern industry, due to their crucial role in the development of new cutting-edge technologies. High demand and limited resources of REEs in Europe, combined with potential environmental problems, enforce the development of innovative low-cost techniques and materials to recover these elements from e-waste and wastewaters. In this context, sorption methods have shown advantages to pre-concentrate REEs from wastewaters and several studies have reported the use of diverse nanomaterials for these purposes, although mostly describing the sorption of REEs from synthetic and mono-elemental solutions at unrealistic metal concentrations. This review is a one-stop-reference by bringing together recent research works in the scope of the application of carbon nanomaterials for the recovery of REEs from water.
Celso E. D. Cardoso; Joana C. Almeida; Cláudia B. Lopes; Tito Trindade; Carlos Vale; Eduarda Pereira. Recovery of Rare Earth Elements by Carbon-Based Nanomaterials—A Review. Nanomaterials 2019, 9, 814 .
AMA StyleCelso E. D. Cardoso, Joana C. Almeida, Cláudia B. Lopes, Tito Trindade, Carlos Vale, Eduarda Pereira. Recovery of Rare Earth Elements by Carbon-Based Nanomaterials—A Review. Nanomaterials. 2019; 9 (6):814.
Chicago/Turabian StyleCelso E. D. Cardoso; Joana C. Almeida; Cláudia B. Lopes; Tito Trindade; Carlos Vale; Eduarda Pereira. 2019. "Recovery of Rare Earth Elements by Carbon-Based Nanomaterials—A Review." Nanomaterials 9, no. 6: 814.
Reliable determination of mercury (Hg) in natural waters is a major analytical challenge due to its low concentration and to the risk of Hg losses or contamination during sampling, storage and pre-treatment of samples. The present work proposes a simple, efficient, sensitive and easy-handling methodology for extraction, pre-concentration and quantification of total dissolved mercury in natural waters, using iron oxide nanoparticles (NPs) coated with silica shells functionalized with dithiocarbamate groups ([email protected]). Ten mg L-1 of these NPs were sufficient to remove 83 to 97% of 500 to 10 ng L-1 of Hg in ultra-pure water and artificial seawater, used as model Hg solutions, within 24 hours. Mercury sorbed to the NPs was then measured directly by thermal decomposition atomic absorption spectrometry with gold amalgamation. The detection limit of approximately 1.8 ng L-1 is lower than the values reported in dispersive solid phase extraction for other magnetic sorbents. As a proof-of-concept, the proposed methodology was successfully tested in real samples of fresh and saline waters and more than 91% of Hg was recovered. With this methodology the extraction and pre-concentration steps may be carried out in situ decreasing the risk of Hg losses or contamination during sampling, storage and pre-treatment of water samples.
Daniela Tavares; Carlos Vale; Cláudia Lopes; Tito Trindade; Eduarda Pereira. Reliable quantification of mercury in natural waters using surface modified magnetite nanoparticles. Chemosphere 2018, 220, 565 -573.
AMA StyleDaniela Tavares, Carlos Vale, Cláudia Lopes, Tito Trindade, Eduarda Pereira. Reliable quantification of mercury in natural waters using surface modified magnetite nanoparticles. Chemosphere. 2018; 220 ():565-573.
Chicago/Turabian StyleDaniela Tavares; Carlos Vale; Cláudia Lopes; Tito Trindade; Eduarda Pereira. 2018. "Reliable quantification of mercury in natural waters using surface modified magnetite nanoparticles." Chemosphere 220, no. : 565-573.
Carlos De Oliveira Amorim; João Nuno Santos Gonçalves; Daniela Tavares; Abel S. Fenta; Cláudia B. Lopes; Eduarda Pereira; Tito Trindade; João G. Correia; Vitor Amaral. Ultra sensitive quantification of Hg 2+ sorption by functionalized nanoparticles using radioactive tracker spectroscopy. Microchemical Journal 2018, 138, 418 -423.
AMA StyleCarlos De Oliveira Amorim, João Nuno Santos Gonçalves, Daniela Tavares, Abel S. Fenta, Cláudia B. Lopes, Eduarda Pereira, Tito Trindade, João G. Correia, Vitor Amaral. Ultra sensitive quantification of Hg 2+ sorption by functionalized nanoparticles using radioactive tracker spectroscopy. Microchemical Journal. 2018; 138 ():418-423.
Chicago/Turabian StyleCarlos De Oliveira Amorim; João Nuno Santos Gonçalves; Daniela Tavares; Abel S. Fenta; Cláudia B. Lopes; Eduarda Pereira; Tito Trindade; João G. Correia; Vitor Amaral. 2018. "Ultra sensitive quantification of Hg 2+ sorption by functionalized nanoparticles using radioactive tracker spectroscopy." Microchemical Journal 138, no. : 418-423.
This research describes the synthesis and characterization of a periodic mesoporous organosilica (PMO) with low thiol density, and its efficiency to trap Hg(II) from waters under realistic environmental conditions. Despite the low density of SH groups grafted to the silanol groups of the pristine PMO, the functionalized material displays effective (92%) and rapid (5 min) extraction of Hg(II) from ultra-pure water. The complete extraction (98%) was achieved in 15 min. The kinetic sorption is well fitted by the pseudo second-order kinetic model (R2 ranged from 0.994 to 1.000), suggesting a chemisorption mechanism, under the experimental conditions tested. The maximum sorption capacity is not limited to the number of the sulfur coordination sites, and multi-layer and physical adsorption may occur for high Hg(II) concentrations. In the range of experimental conditions used, the mathematical function that better describes the equilibrium data is given by the Freundlich model (R2 = 0.969). It is also demonstrated that the PMO with low sulfur density keeps its high efficiency for Hg(II) in spiked natural waters, of different chemical composition and salinity, as a proof-of-concept for its potential application in water treatment systems to remove Hg(II). In comparison with other PMO materials reported in literature, the low sulfur density PMO is a cheap, effective and safe alternative PMO material for application to low Hg(II) contaminated waters, minimizing the hazardous effects that the organic functionalization may cause to the environment and biota, and consequently, to human health.
Paula Figueira; Mirtha Lourenço; E. Pereira; José Gomes; P. Ferreira; C.B. Lopes. Periodic mesoporous organosilica with low thiol density – a safer material to trap Hg(II) from water. Journal of Environmental Chemical Engineering 2017, 5, 5043 -5053.
AMA StylePaula Figueira, Mirtha Lourenço, E. Pereira, José Gomes, P. Ferreira, C.B. Lopes. Periodic mesoporous organosilica with low thiol density – a safer material to trap Hg(II) from water. Journal of Environmental Chemical Engineering. 2017; 5 (5):5043-5053.
Chicago/Turabian StylePaula Figueira; Mirtha Lourenço; E. Pereira; José Gomes; P. Ferreira; C.B. Lopes. 2017. "Periodic mesoporous organosilica with low thiol density – a safer material to trap Hg(II) from water." Journal of Environmental Chemical Engineering 5, no. 5: 5043-5053.
Pristine, amino monofunctionalized and amino and thiol bifunctionalized phenylene-bridged periodic mesoporous organosilicas (Ph-PMO) were synthetized by a simple methodology without any protection/deprotection steps. The Ph-PMO materials were characterized and their potential as new sorbents for Hg(II) was investigated for low-contamination scenarios. The materials have well-ordered mesostructures as confirmed by powder X-ray diffraction and transmission electron microscopy analyses. 13C and 29Si solid-state NMR confirm the amination of the phenylene bridge of the simple Ph-PMO to form the amine-functionalized PMO (NH2-Ph-PMO) and the grafting of the thiol silylated ligand to the free silanols of the NH2-Ph-PMO to obtain the bifunctional (NH2-Ph-PMO-SH). For the initial conditions tested, the bifunctional material showed excellent Hg(II) removal efficiency (98%) and Hg(II) uptake time (30 min). The sorption kinetics were also investigated by three of the most studied kinetic models, and the pseudo-second-order kinetic model was the one that better described the kinetic sorption process of Hg(II) ions onto all PMO.
Mirtha Lourenço; Paula Figueira; E. Pereira; José Gomes; C.B. Lopes; P. Ferreira. Simple, mono and bifunctional periodic mesoporous organosilicas for removal of priority hazardous substances from water: The case of mercury(II). Chemical Engineering Journal 2017, 322, 263 -274.
AMA StyleMirtha Lourenço, Paula Figueira, E. Pereira, José Gomes, C.B. Lopes, P. Ferreira. Simple, mono and bifunctional periodic mesoporous organosilicas for removal of priority hazardous substances from water: The case of mercury(II). Chemical Engineering Journal. 2017; 322 ():263-274.
Chicago/Turabian StyleMirtha Lourenço; Paula Figueira; E. Pereira; José Gomes; C.B. Lopes; P. Ferreira. 2017. "Simple, mono and bifunctional periodic mesoporous organosilicas for removal of priority hazardous substances from water: The case of mercury(II)." Chemical Engineering Journal 322, no. : 263-274.
Metal uptake from contaminated waters by living Ulva lactuca was studied during 6 days, under different relevant contamination scenarios. In mono-metallic solutions, with concentrations ranging from 10 to 100 μg L for Hg, 10-200 μg L for Cd, and 50-1000 μg L for Pb, macroalgae (500 mg L, d.w.) were able to remove, in most cases 93-99% of metal, allowing to achieve water quality criteria regarding both surface and drinking waters. In multi-metallic solutions, comprising simultaneously the three metals, living macroalgae still performed well, with Hg removal (c.a. 99%) not being significantly affected by the presence of Cd and Pb, even when those metals were in higher concentrations. Removal efficiencies for Cd and Pb varied between 57 and 96%, and 34-97%, respectively, revealing an affinity of U. lactuca toward metals: Hg > Cd > Pb. Chemical quantification in macroalgae, after bioaccumulation assays demonstrated that all Cd and Hg removed from solution was really bound in macroalgae biomass, while only half of Pb showed to be sorbed on the biomass. Overall, U. lactuca accumulated up to 209 μg g of Hg, up to 347 μg g of Cd and up to 1641 μg g of Pb, which correspond to bioconcentration factors ranging from 500 to 2200, in a dose-dependent accumulation. Pseudo-first order, pseudo-second order and Elovich models showed a good performance in describing the kinetics of bioaccumulation, in the whole period of time. In the range of experimental conditions used, no mortality was observed and U. lactuca relative growth rate was not significantly affected by the presence of metals. Results represent an important contribution for developing a macroalgae-based biotechnology, applied for contaminated saline water remediation, more "green" and cost-effective than conventional treatment methods.
Bruno Henriques; Luciana Rocha; Cláudia Lopes; Paula Figueira; Armando Duarte; Carlos Vale; M.A. Pardal; Eduarda Pereira. A macroalgae-based biotechnology for water remediation: Simultaneous removal of Cd, Pb and Hg by living Ulva lactuca. Journal of Environmental Management 2017, 191, 275 -289.
AMA StyleBruno Henriques, Luciana Rocha, Cláudia Lopes, Paula Figueira, Armando Duarte, Carlos Vale, M.A. Pardal, Eduarda Pereira. A macroalgae-based biotechnology for water remediation: Simultaneous removal of Cd, Pb and Hg by living Ulva lactuca. Journal of Environmental Management. 2017; 191 ():275-289.
Chicago/Turabian StyleBruno Henriques; Luciana Rocha; Cláudia Lopes; Paula Figueira; Armando Duarte; Carlos Vale; M.A. Pardal; Eduarda Pereira. 2017. "A macroalgae-based biotechnology for water remediation: Simultaneous removal of Cd, Pb and Hg by living Ulva lactuca." Journal of Environmental Management 191, no. : 275-289.
Results of 7-days exposure to metals, using environmentally realistic conditions, evidenced the high potential of living Fucus vesiculosus to remove Pb, Hg and Cd from contaminated salt waters. For different contamination scenarios (single- and multi-contamination), ca 450 mg L (dry weight), enable to reduce the concentrations of Pb in 65%, of Hg in 95% and of Cd between 25 and 76%. Overall, bioconcentration factors ranged from 600 to 2300. Elovich kinetic model described very well the bioaccumulation of Pb and Cd over time, while pseudo-second-order model adjusted better to experimental data regarding Hg. F. vesiculosus showed different affinity toward studied metals, following the sequence order: Hg > Pb > Cd. Analysis of metal content in the macroalgae after bioaccumulation, proved that all metal removed from solution was bound to the biomass. Depuration experiments reveled no significant loss of metal back to solution. Exposure to contaminants only adversely affected the organism's growth for the highest concentrations of Cd and Pb. Findings are an important contribute for the development of remediation biotechnologies for confined saline waters contaminated with trace metal contaminants, more efficient and with lower costs than the traditional treatment methods.
Bruno Henriques; Cláudia Lopes; Paula Figueira; Luciana Rocha; Armando Duarte; Carlos Vale; Miguel A. Pardal; Eduarda Pereira. Bioaccumulation of Hg, Cd and Pb by Fucus vesiculosus in single and multi-metal contamination scenarios and its effect on growth rate. Chemosphere 2017, 171, 208 -222.
AMA StyleBruno Henriques, Cláudia Lopes, Paula Figueira, Luciana Rocha, Armando Duarte, Carlos Vale, Miguel A. Pardal, Eduarda Pereira. Bioaccumulation of Hg, Cd and Pb by Fucus vesiculosus in single and multi-metal contamination scenarios and its effect on growth rate. Chemosphere. 2017; 171 ():208-222.
Chicago/Turabian StyleBruno Henriques; Cláudia Lopes; Paula Figueira; Luciana Rocha; Armando Duarte; Carlos Vale; Miguel A. Pardal; Eduarda Pereira. 2017. "Bioaccumulation of Hg, Cd and Pb by Fucus vesiculosus in single and multi-metal contamination scenarios and its effect on growth rate." Chemosphere 171, no. : 208-222.
Dithiocarbamate-functionalized magnetite nanoparticles ([email protected]/SiDTC) have been investigated as a convenient and effective sorbent for mercury removal from river, estuarine and sea waters, and their capability to decrease realistic environmental concentrations to the new environmental quality standards was evaluated. The sorption kinetics was well described by the Elovich model and the initial sorption rate was dependent of the sorbent dose. Except for river water sample, the [email protected]/SiDTC particles uptake 99.9% or more of the Hg(II) in the waters (initially at the concentration of 50 μg/L), allowing to reach residual concentrations lower than the new environmental quality standards (70 ng/L) with only 10 mg/L of sorbent material. The distribution coefficients of mercuric ions between the magnetic particles and the different natural water types were above 10 mL/g for the river water and above 10 mL/g for the estuarine and sea waters. The differences observed between the water types can be attributed to different water composition (effect of the matrix), which plays an important role in the efficiency of the water treatment.
Daniela S. Tavares; Cláudia B. Lopes; Ana Luísa Daniel-Da-Silva; Carlos Vale; Tito Trindade; Maria E. Pereira. Mercury in river, estuarine and seawaters – Is it possible to decrease realist environmental concentrations in order to achieve environmental quality standards? Water Research 2016, 106, 439 -449.
AMA StyleDaniela S. Tavares, Cláudia B. Lopes, Ana Luísa Daniel-Da-Silva, Carlos Vale, Tito Trindade, Maria E. Pereira. Mercury in river, estuarine and seawaters – Is it possible to decrease realist environmental concentrations in order to achieve environmental quality standards? Water Research. 2016; 106 ():439-449.
Chicago/Turabian StyleDaniela S. Tavares; Cláudia B. Lopes; Ana Luísa Daniel-Da-Silva; Carlos Vale; Tito Trindade; Maria E. Pereira. 2016. "Mercury in river, estuarine and seawaters – Is it possible to decrease realist environmental concentrations in order to achieve environmental quality standards?" Water Research 106, no. : 439-449.
The efficiency of chitosan cross-linked with genipin (Chg) and cross-linked with genipin and grafted with caffeic acid (Chg+caf) to remove Hg(II) from waters was investigated. An optimal dose of 50 mg L-1 for both chitosan films was selected based on the equilibrium removal percentage and on the contact time required to attain the equilibrium. The sorption extent was dependent on the initial Hg(II) concentration (CHg,0CHg,0), with removal efficiencies varying between 79% and 82% for CHg,0=0.05CHg,0=0.05 mg L-1 and between 89% and 94% for CHg,0=0.50CHg,0=0.50 mg L-1. Under ion competition, the Chg and Chg+caf films showed to be effective and selective for mercury in multimetallic solutions containing also cadmium and lead. In the case of natural river and seawaters, the mercury speciation played an important role in the overall sorption process, reducing the percentage removal of Hg. In terms of modeling, the kinetic data were well described by pseudo-first and pseudo-second order models, depending on the experimental conditions. The diffusion models suggested that the entire sorption process of Hg(II) by both Cg and Cg+caf films was essentially controlled by pore diffusion. The equilibrium data were well described by the Sips isotherm, and the estimated capacity was 2.2 and 4.0 mg g-1 for Chg and Chg+caf films, respectively. In the whole, the results showed that the sorption efficiency was improved by grafting caffeic acid to the polymeric chains of chitosan cross-linked with genipin.
Luciana S. Rocha; Ângela Almeida; Cláudia Nunes; Bruno Henriques; Manuel A. Coimbra; Cláudia B. Lopes; Carlos M. Silva; Armando C. Duarte; Eduarda Pereira. Simple and effective chitosan based films for the removal of Hg from waters: Equilibrium, kinetic and ionic competition. Chemical Engineering Journal 2016, 300, 217 -229.
AMA StyleLuciana S. Rocha, Ângela Almeida, Cláudia Nunes, Bruno Henriques, Manuel A. Coimbra, Cláudia B. Lopes, Carlos M. Silva, Armando C. Duarte, Eduarda Pereira. Simple and effective chitosan based films for the removal of Hg from waters: Equilibrium, kinetic and ionic competition. Chemical Engineering Journal. 2016; 300 ():217-229.
Chicago/Turabian StyleLuciana S. Rocha; Ângela Almeida; Cláudia Nunes; Bruno Henriques; Manuel A. Coimbra; Cláudia B. Lopes; Carlos M. Silva; Armando C. Duarte; Eduarda Pereira. 2016. "Simple and effective chitosan based films for the removal of Hg from waters: Equilibrium, kinetic and ionic competition." Chemical Engineering Journal 300, no. : 217-229.
The study aimed to evaluate the efficiency of dithiocarbamate functionalized silica coated magnetite nanoparticles (NPs) for Hg decontamination of saltwater either contaminated with Hg alone or with As and Cd. For this, the residual levels of Hg in seawater were assessed and Hg-contaminated or Hg + As + Cd-contaminated seawater toxicity to aquatic biota, before and after the sorption process, was compared. The results showed that under highly competitive conditions (water salts, Cd and As), the removal of Hg from seawater, by using these magnetic NPs, for the lowest concentration (50 μg/L) was superior to 98% and for the highest concentration (500 μg/L) ranged between 61% to 67%. Despite the great affinity of the magnetic NPs for Hg, they were not effective at removing As and Cd from seawater. In relation to the ecotoxicity endpoints after remediation, the mixture with lower Hg concentration exhibited no toxicity to rotifer Brachionus plicatilis and bacteria Vibrio fischeri ; however, the mixture with higher concentration revealed toxicity. In addition, the toxicity of bacteria V. fischeri, rotifer B. plicatilis and algae Phaeodactylum tricornutum, whose responses where inhibited during its exposure to the non-remediate sample was considerably reduced after treatment with NPs. Furthermore, microalgae P. tricornutum appears to be most sensitive species while Artemia franciscana showed no toxic effects to the tested solutions. Both chemical and ecotoxicological approaches revealed a high efficiency for the remediation of Hg-contaminated saltwater.
Iram Mohmood; Cláudia Lopes; Isabel Lopes; Daniela Tavares; Amadeu Soares; Armando Duarte; Tito Trindade; Iqbal Ahmad; Eduarda Pereira. Remediation of mercury contaminated saltwater with functionalized silica coated magnetite nanoparticles. Science of The Total Environment 2016, 557-558, 712 -721.
AMA StyleIram Mohmood, Cláudia Lopes, Isabel Lopes, Daniela Tavares, Amadeu Soares, Armando Duarte, Tito Trindade, Iqbal Ahmad, Eduarda Pereira. Remediation of mercury contaminated saltwater with functionalized silica coated magnetite nanoparticles. Science of The Total Environment. 2016; 557-558 ():712-721.
Chicago/Turabian StyleIram Mohmood; Cláudia Lopes; Isabel Lopes; Daniela Tavares; Amadeu Soares; Armando Duarte; Tito Trindade; Iqbal Ahmad; Eduarda Pereira. 2016. "Remediation of mercury contaminated saltwater with functionalized silica coated magnetite nanoparticles." Science of The Total Environment 557-558, no. : 712-721.
The biosorption capability of two marine macroalgae (green Ulva lactuca and brown Fucus vesiculosus) was evaluated in the removal of toxic metals (Hg, Cd and Pb) from saline waters, under realistic conditions. Results showed that, independently of the contamination scenario tested, both macroalgae have a remarkable capacity to biosorb Hg and Pb. In single-contaminant systems, by using only c.a. 500 mg of non-pre-treated algae biomass (size Pb> > Cd, although Pb removal by U. lactuca was more inhibited than that achieved by F. vesiculosus. Under the experimental conditions used, none of the macroalgae was effective to remove Cd (maximum removal of 20 %). In all cases, the kinetics of biosorption was mathematically described with success. Globally, it became clear that the studied macroalgae may be part of simple, efficient, and cost-effective water treatment technologies. Nevertheless, Fucus vesiculosus has greater potential, since it always presented higher initial sorption rates and higher removal efficiencies.
Paula Figueira; Bruno Henriques; Ana Teixeira; Cláudia Lopes; Ana Teresa Reis; Rui Monteiro; Armando Duarte; M. A. Pardal; Eduarda Pereira. Comparative study on metal biosorption by two macroalgae in saline waters: single and ternary systems. Environmental Science and Pollution Research 2016, 23, 11985 -11997.
AMA StylePaula Figueira, Bruno Henriques, Ana Teixeira, Cláudia Lopes, Ana Teresa Reis, Rui Monteiro, Armando Duarte, M. A. Pardal, Eduarda Pereira. Comparative study on metal biosorption by two macroalgae in saline waters: single and ternary systems. Environmental Science and Pollution Research. 2016; 23 (12):11985-11997.
Chicago/Turabian StylePaula Figueira; Bruno Henriques; Ana Teixeira; Cláudia Lopes; Ana Teresa Reis; Rui Monteiro; Armando Duarte; M. A. Pardal; Eduarda Pereira. 2016. "Comparative study on metal biosorption by two macroalgae in saline waters: single and ternary systems." Environmental Science and Pollution Research 23, no. 12: 11985-11997.
Mercury and cadmium are considered by the water framework directive priority hazardous substances. In this work, the capacity of crab carapace and clam shell wastes to remove mercury and cadmium from water was evaluated under batch conditions, for realistic contamination scenarios in monometallic and binary solutions. The results evidenced that in monometallic solutions and under studied operational conditions, both biosorbents can achieve Hg2+ removal efficiencies higher than 80% and the kinetic process is well described by two of the most widely used equations, the pseudo-second order and the Elovich model. In terms of biosorption equilibrium, crab carapace and clam shell wastes displayed very distinct behaviours. While clam shells achieve the complete monolayer coverage and the isotherm is well described by the Langmuir model, crab carapace powder display a more unusual behaviour, that is well described by the BET isotherm, and is characterized by an almost convex shape to the concentration axis, with an infinite slope for an Hg2+ concentration in solution around 25 μg/L. In binary solutions, both wastes are able to uptake simultaneously Hg2+ and Cd2+, however the uptake of Hg2+ was inhibited in some extent, attributed to the high kinetic and equilibrium selectivities of the bio-wastes for cadmium.
Rui J.R. Monteiro; Cláudia B. Lopes; Luciana S. Rocha; João P. Coelho; Armando C. Duarte; E. Pereira. Sustainable approach for recycling seafood wastes for the removal of priority hazardous substances (Hg and Cd) from water. Journal of Environmental Chemical Engineering 2016, 4, 1199 -1208.
AMA StyleRui J.R. Monteiro, Cláudia B. Lopes, Luciana S. Rocha, João P. Coelho, Armando C. Duarte, E. Pereira. Sustainable approach for recycling seafood wastes for the removal of priority hazardous substances (Hg and Cd) from water. Journal of Environmental Chemical Engineering. 2016; 4 (1):1199-1208.
Chicago/Turabian StyleRui J.R. Monteiro; Cláudia B. Lopes; Luciana S. Rocha; João P. Coelho; Armando C. Duarte; E. Pereira. 2016. "Sustainable approach for recycling seafood wastes for the removal of priority hazardous substances (Hg and Cd) from water." Journal of Environmental Chemical Engineering 4, no. 1: 1199-1208.
This study aimed to assess and explore the bioaccumulation capabilities of three different macroalgae species, Ulva lactuca (green), Gracilaria gracilis (red) and Fucus vesiculosus (brown), very common on temperate coasts and estuaries, for the removal of mercury (Hg) from contaminated waters (with high salinity), using environmentally realistic concentrations of metal (10–100 lg L 1). Levels of Hg accumulated by all seaweeds ranged between 20.8 and 208 lg g 1, corresponding to bioconcentration factors of c.a. 2000. A comparative evaluation of bioaccumulation (living biomass) and biosorption (dried biomass) was performed for U. lactuca, which had displayed the best performance in accumulating Hg. The removal conducted by the living seaweed (mmacroalgae/Vsolution 500 mg L 1), although slower, was more promising since all Hg levels were reduced by about 99%, fulfilling the European criteria for drinking water quality. Pseudo-second-order and Elovich models described quite well the experimental data, assuming a process essentially of chemical nature. Determination of total Hg content in algal biomass over time, allowed to confirm and to follow the uptake of this metal by the living organism. Volatilization of Hg or its conversion to organo-metallic forms (0.02–0.05%) was negligible during the decontamination process. Overall, the results are a contribution for the development of an efficient and cost-effective water remediation biotechnology, based on the use of living macroalgae to promote the removal of Hg
Bruno Henriques; Luciana Rocha; Cláudia Lopes; Paula Figueira; Rui Monteiro; Armando Duarte; M.A. Pardal; Eduarda Pereira. Study on bioaccumulation and biosorption of mercury by living marine macroalgae: Prospecting for a new remediation biotechnology applied to saline waters. Chemical Engineering Journal 2015, 281, 759 -770.
AMA StyleBruno Henriques, Luciana Rocha, Cláudia Lopes, Paula Figueira, Rui Monteiro, Armando Duarte, M.A. Pardal, Eduarda Pereira. Study on bioaccumulation and biosorption of mercury by living marine macroalgae: Prospecting for a new remediation biotechnology applied to saline waters. Chemical Engineering Journal. 2015; 281 ():759-770.
Chicago/Turabian StyleBruno Henriques; Luciana Rocha; Cláudia Lopes; Paula Figueira; Rui Monteiro; Armando Duarte; M.A. Pardal; Eduarda Pereira. 2015. "Study on bioaccumulation and biosorption of mercury by living marine macroalgae: Prospecting for a new remediation biotechnology applied to saline waters." Chemical Engineering Journal 281, no. : 759-770.
One of the recognized challenges in chemical extraction of mercury from soil is the diversity of procedures that are currently available in literature and that differ in terms of the extractant solution used, soil:extractant ratio and duration of extraction. Therefore, this study focused on establishing the role of operational parameters for extraction of the available and labile fractions of mercury from soils, considering different soil:extractant ratios and the kinetics of extraction. The suitability of 1.0 mol L− 1 ammonium acetate at pH 7 and 0.1 mol L− 1 HCl as extractants for the available fraction and the extraction of the labile fraction using 0.5 mol L− 1 hydrochloric acid was investigated. No statistical differences were found between ammonium acetate and 0.1 mol L− 1 HCl; therefore both extractants can be used for estimating the available fraction. It was also observed that a soil:extractant ratio of 1.5 g of soil to 100 mL of extractant favors mercury extraction. For the available fraction an extraction of 30 min seems enough, as no further significant change was observed in the quantity of mercury extracted thereafter. For the labile fraction increase the extraction duration to at least 24 h is recommended. The data was fitted into kinetic models, and it was observed that the two first-order reactions and the diffusion models help to understand the behavior of mercury extraction from soil, clearly showing that in all cases the rate of mercury extraction was faster in the first 10 h and declined after that period. The characteristics of the soil influenced the extraction of mercury, and it was verified that pH and particle size of the soil influenced the mercury extraction process, as results suggested that an acidic soil might have a reduced ability to strongly retain metals and soils with higher porosity showed lower rates of mercury extraction.
Ana Teresa Reis; Cláudia B. Lopes; Christine M. Davidson; Armando C. Duarte; Eduarda Pereira. Extraction of available and labile fractions of mercury from contaminated soils: The role of operational parameters. Geoderma 2015, 259-260, 213 -223.
AMA StyleAna Teresa Reis, Cláudia B. Lopes, Christine M. Davidson, Armando C. Duarte, Eduarda Pereira. Extraction of available and labile fractions of mercury from contaminated soils: The role of operational parameters. Geoderma. 2015; 259-260 ():213-223.
Chicago/Turabian StyleAna Teresa Reis; Cláudia B. Lopes; Christine M. Davidson; Armando C. Duarte; Eduarda Pereira. 2015. "Extraction of available and labile fractions of mercury from contaminated soils: The role of operational parameters." Geoderma 259-260, no. : 213-223.