<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Araújo, Geórgia C L</style></author><author><style face="normal" font="default" size="100%">Lemos, Sherlan G</style></author><author><style face="normal" font="default" size="100%">Nabais, Cristina</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nickel sorption capacity of ground xylem of Quercus ilex trees and effects of selected ligands present in the xylem sap.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of plant physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adsorption isotherms</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Organic ligands</style></keyword><keyword><style  face="normal" font="default" size="100%">Xylem</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><volume><style face="normal" font="default" size="100%">166</style></volume><pages><style face="normal" font="default" size="100%">270-277</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this work the influence of four different ligands present in the xylem sap of Quercus ilex (histidine, citric, oxalic and aspartic acids) on Ni(II) adsorption by xylem was investigated. Grinded xylem was trapped in acrylic columns and solutions of Ni(II), in the absence and presence of the four ligands prepared in KNO(3) 0.1molL(-1) at pH 5.5, were percolated through the column. Aliquots of solutions were recovered in the column end for Ni determination by graphite furnace atomic absorption spectrometry (GFAAS). The experimental data to describe Ni sorption by xylem in both the presence and absence of ligands was better explained by the Freundlich isotherm model. The decreasing affinity order of ligands for Ni was: oxalic acid&gt;citric acid&gt;histidine&gt;aspartic acid. On the other hand, the Ni(II) adsorption by xylem increased following the inverse sequence of ligands. Potentiometric titrations of acidic groups were carried out to elucidate the sorption site groups available in Q. ilex xylem. The potentiometric titration has shown three sorption sites: pK(a) 2.6 (57.7% of the sorption sites), related to monobasic aliphatic carboxylic acids or nitrogen aromatic bases, pK(a) 8.1 (9.6%) and pK(a) 9.9 (32.7%), related to phenolic groups.</style></abstract><accession-num><style face="normal" font="default" size="100%">18707798</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Araújo, Geórgia C. L.</style></author><author><style face="normal" font="default" size="100%">Lemos, Sherlan G.</style></author><author><style face="normal" font="default" size="100%">Nabais, Cristina</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nickel sorption capacity of ground xylem of Quercus ilex trees and effects of selected ligands present in the xylem sap.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of plant physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adsorption isotherms</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Organic ligands</style></keyword><keyword><style  face="normal" font="default" size="100%">Xylem</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/18707798</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">166</style></volume><pages><style face="normal" font="default" size="100%">270 - 277</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this work the influence of four different ligands present in the xylem sap of Quercus ilex (histidine, citric, oxalic and aspartic acids) on Ni(II) adsorption by xylem was investigated. Grinded xylem was trapped in acrylic columns and solutions of Ni(II), in the absence and presence of the four ligands prepared in KNO(3) 0.1molL(-1) at pH 5.5, were percolated through the column. Aliquots of solutions were recovered in the column end for Ni determination by graphite furnace atomic absorption spectrometry (GFAAS). The experimental data to describe Ni sorption by xylem in both the presence and absence of ligands was better explained by the Freundlich isotherm model. The decreasing affinity order of ligands for Ni was: oxalic acid&gt;citric acid&gt;histidine&gt;aspartic acid. On the other hand, the Ni(II) adsorption by xylem increased following the inverse sequence of ligands. Potentiometric titrations of acidic groups were carried out to elucidate the sorption site groups available in Q. ilex xylem. The potentiometric titration has shown three sorption sites: pK(a) 2.6 (57.7% of the sorption sites), related to monobasic aliphatic carboxylic acids or nitrogen aromatic bases, pK(a) 8.1 (9.6%) and pK(a) 9.9 (32.7%), related to phenolic groups.</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 18707798</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Abreu, M. M.</style></author><author><style face="normal" font="default" size="100%">Matias, M. J.</style></author><author><style face="normal" font="default" size="100%">Magalhães, M. Clara F.</style></author><author><style face="normal" font="default" size="100%">Basto, M. J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Impacts on water, soil and plants from the abandoned Miguel Vacas copper mine, Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geochemical Exploration</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">carbonates copper mine</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">phosphates</style></keyword><keyword><style  face="normal" font="default" size="100%">prunus domestica</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">soil copper contamination</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0375674207000490</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">96</style></volume><pages><style face="normal" font="default" size="100%">161 - 170</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Soil, water and plant geochemistry was studied around the Miguel Vacas copper mine (Alentejo, SE Portugal), which stopped its exploitation and processing activities in 1991. After closure waste-rock piles remained exposed to weathering. The copper ore was mainly composed of copper phosphates and carbonates. Remediation actions were insufficient to prevent the spreading of waste-rock materials to surrounding farmed fields. The latter caused contamination of soils and water. Based on overall characteristics water from wells and surface stream water mostly can be classified as of the sulphate magnesium type. The application of a chemical equilibrium model to the sampled water showed that copper, phosphate and sulphate concentrations are controlled by copper(II) secondary minerals (pseudomalachite, libethenite and malachite) and gypsum. Nevertheless, groundwater can be used for irrigation and cattle based on quality parameters. Soils and plants (Prunus domestica L., Olea europaea L. spp. europaea and Quercus ilex L.) were collected southeast of the open pit and the exploitation substructures. The soils located in the influence of drainage water that percolated through waste material or exploitation substructures were contaminated with Cu, and Ni was close to the maximum value allowed by Portuguese legislation. These soils, however, did not show elevated Zn and Mn concentrations. The trace element content in plants was within the normal range, with Q. ilex being able to accumulate Mn and to some extent also Ni. Dispersion of trace elements seemed to be limited to a distance 1500 m down from the waste dumps in southeastern direction.</style></abstract><issue><style face="normal" font="default" size="100%">2-3</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Abreu, M M</style></author><author><style face="normal" font="default" size="100%">Matias, M J</style></author><author><style face="normal" font="default" size="100%">Magalhães, M Clara F</style></author><author><style face="normal" font="default" size="100%">Basto, M J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Impacts on water, soil and plants from the abandoned Miguel Vacas copper mine, Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geochemical Exploration</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">carbonates copper mine</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">phosphates</style></keyword><keyword><style  face="normal" font="default" size="100%">prunus domestica</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">soil copper contamination</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><volume><style face="normal" font="default" size="100%">96</style></volume><pages><style face="normal" font="default" size="100%">161-170</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Soil, water and plant geochemistry was studied around the Miguel Vacas copper mine (Alentejo, SE Portugal), which stopped its exploitation and processing activities in 1991. After closure waste-rock piles remained exposed to weathering. The copper ore was mainly composed of copper phosphates and carbonates. Remediation actions were insufficient to prevent the spreading of waste-rock materials to surrounding farmed fields. The latter caused contamination of soils and water. Based on overall characteristics water from wells and surface stream water mostly can be classified as of the sulphate magnesium type. The application of a chemical equilibrium model to the sampled water showed that copper, phosphate and sulphate concentrations are controlled by copper(II) secondary minerals (pseudomalachite, libethenite and malachite) and gypsum. Nevertheless, groundwater can be used for irrigation and cattle based on quality parameters. Soils and plants (Prunus domestica L., Olea europaea L. spp. europaea and Quercus ilex L.) were collected southeast of the open pit and the exploitation substructures. The soils located in the influence of drainage water that percolated through waste material or exploitation substructures were contaminated with Cu, and Ni was close to the maximum value allowed by Portuguese legislation. These soils, however, did not show elevated Zn and Mn concentrations. The trace element content in plants was within the normal range, with Q. ilex being able to accumulate Mn and to some extent also Ni. Dispersion of trace elements seemed to be limited to a distance 1500 m down from the waste dumps in southeastern direction.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Correia dos Santos, Margarida Maria</style></author><author><style face="normal" font="default" size="100%">Alves, Sheila</style></author><author><style face="normal" font="default" size="100%">de Lurdes Simões Gonçalves, Maria</style></author><author><style face="normal" font="default" size="100%">Correia dos Santos, Margarida Maria</style></author><author><style face="normal" font="default" size="100%">Alves, Sheila</style></author><author><style face="normal" font="default" size="100%">de Lurdes Simões Gonçalves, Maria</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Kinetics and Mechanism of Ni(II) Chelation in Model and Real Solutions of Xylem Sap of Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Electroanalysis</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">10</style></keyword><keyword><style  face="normal" font="default" size="100%">1002</style></keyword><keyword><style  face="normal" font="default" size="100%">200703972</style></keyword><keyword><style  face="normal" font="default" size="100%">Complexation</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclic voltammetry</style></keyword><keyword><style  face="normal" font="default" size="100%">doi</style></keyword><keyword><style  face="normal" font="default" size="100%">elan</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Xylem sap</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year></dates><publisher><style face="normal" font="default" size="100%">WILEY-VCH Verlag</style></publisher><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">2351-2361</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The kinetics of formation and dissociation of Ni(II) complexes with oxalic and citric acids was studied by cyclic voltammetry in model solutions of xylem sap of Q. ilex (the dominant tree growing on serpentine soils of Northeast Portugal) using representative concentrations, pH and ionic strength. The role of magnesium on complex formation was analyzed from solutions where Mg is present at concentration levels found in the xylem sap of Q. ilex growing on both nonserpentine and serpentine soils. Kinetics studies were also done in diluted solutions of real xylem sap samples, spiked with increasing amounts of magnesium. The values obtained for the apparent rate constants were those anticipated by the proposed model. To test the validity of the methodology and mechanisms, formation rate constants, kf (M−1 s−1) of Ni(II) complexes with citrate and oxalate were evaluated that compare with the values from Eigen mechanism.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Correia dos Santos, Margarida Maria</style></author><author><style face="normal" font="default" size="100%">Alves, Sheila</style></author><author><style face="normal" font="default" size="100%">de Lurdes Simões Gonçalves, Maria</style></author><author><style face="normal" font="default" size="100%">Correia dos Santos, Margarida Maria</style></author><author><style face="normal" font="default" size="100%">Alves, Sheila</style></author><author><style face="normal" font="default" size="100%">de Lurdes Simões Gonçalves, Maria</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Kinetics and Mechanism of Ni(II) Chelation in Model and Real Solutions of Xylem Sap of Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Electroanalysis</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">10</style></keyword><keyword><style  face="normal" font="default" size="100%">1002</style></keyword><keyword><style  face="normal" font="default" size="100%">200703972</style></keyword><keyword><style  face="normal" font="default" size="100%">Complexation</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclic voltammetry</style></keyword><keyword><style  face="normal" font="default" size="100%">doi</style></keyword><keyword><style  face="normal" font="default" size="100%">elan</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Xylem sap</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1002/elan.200703972http://doi.wiley.com/10.1002/elan.200703972</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">2351 - 2361</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The kinetics of formation and dissociation of Ni(II) complexes with oxalic and citric acids was studied by cyclic voltammetry in model solutions of xylem sap of Q. ilex (the dominant tree growing on serpentine soils of Northeast Portugal) using representative concentrations, pH and ionic strength. The role of magnesium on complex formation was analyzed from solutions where Mg is present at concentration levels found in the xylem sap of Q. ilex growing on both nonserpentine and serpentine soils. Kinetics studies were also done in diluted solutions of real xylem sap samples, spiked with increasing amounts of magnesium. The values obtained for the apparent rate constants were those anticipated by the proposed model. To test the validity of the methodology and mechanisms, formation rate constants, kf (M−1 s−1) of Ni(II) complexes with citrate and oxalate were evaluated that compare with the values from Eigen mechanism.</style></abstract><issue><style face="normal" font="default" size="100%">22</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: WILEY-VCH Verlag</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">dos Santos, Margarida Maria Correia</style></author><author><style face="normal" font="default" size="100%">Alves, Sheila</style></author><author><style face="normal" font="default" size="100%">de Lurdes SimõesGonçalves, Maria</style></author><author><style face="normal" font="default" size="100%">Nabais, Cristina</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Dynamic Modelling of Nickel Complexation in Xylem Sap of Quercus ilex: A Voltammetric Study</style></title><secondary-title><style face="normal" font="default" size="100%">Electroanalysis</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Inert complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Mixed complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Semidynamic complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Voltammetry</style></keyword><keyword><style  face="normal" font="default" size="100%">Xylem sap</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1002/elan.200503446</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">18</style></volume><pages><style face="normal" font="default" size="100%">814 - 822</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Holm oak (Quercus ilex) is the dominant tree growing on serpentine soils of northeast Portugal, characterized by elevated soil concentrations of Ni and Mg, combined with low Ca concentrations. Apparently Q. ilex does not suffer from excessive concentrations of Ni in the soil. In this work we report a complexation study of nickel by the relevant ligands present in xylem sap: histidine, aspartic acid, oxalic and citric acids, at 0.10 M ionic strength and pH 5.5. Single and mixed complexes were characterized. To validate the proposed complexation model, diluted solutions of Q. ilex xylem sap were titrated with nickel. All studies were done using square-wave voltammetry (SWV) at a hanging mercury drop electrode. Due to the dynamic nature of SWV, it is possible to obtain the conditional stability constants of the complexes formed but also to have knowledge on the kinetics of the interconversion of the species present.</style></abstract><issue><style face="normal" font="default" size="100%">8</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: WILEY-VCH Verlag</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">dos Santos, Margarida Maria Correia</style></author><author><style face="normal" font="default" size="100%">Alves, Sheila</style></author><author><style face="normal" font="default" size="100%">de Lurdes SimõesGonçalves, Maria</style></author><author><style face="normal" font="default" size="100%">Nabais, Cristina</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Dynamic Modelling of Nickel Complexation in Xylem Sap of Quercus ilex: A Voltammetric Study</style></title><secondary-title><style face="normal" font="default" size="100%">Electroanalysis</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Inert complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Mixed complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Semidynamic complexes</style></keyword><keyword><style  face="normal" font="default" size="100%">Voltammetry</style></keyword><keyword><style  face="normal" font="default" size="100%">Xylem sap</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><publisher><style face="normal" font="default" size="100%">WILEY-VCH Verlag</style></publisher><volume><style face="normal" font="default" size="100%">18</style></volume><pages><style face="normal" font="default" size="100%">814-822</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Holm oak (Quercus ilex) is the dominant tree growing on serpentine soils of northeast Portugal, characterized by elevated soil concentrations of Ni and Mg, combined with low Ca concentrations. Apparently Q. ilex does not suffer from excessive concentrations of Ni in the soil. In this work we report a complexation study of nickel by the relevant ligands present in xylem sap: histidine, aspartic acid, oxalic and citric acids, at 0.10 M ionic strength and pH 5.5. Single and mixed complexes were characterized. To validate the proposed complexation model, diluted solutions of Q. ilex xylem sap were titrated with nickel. All studies were done using square-wave voltammetry (SWV) at a hanging mercury drop electrode. Due to the dynamic nature of SWV, it is possible to obtain the conditional stability constants of the complexes formed but also to have knowledge on the kinetics of the interconversion of the species present.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Villaescusa, Isabel</style></author><author><style face="normal" font="default" size="100%">Fiol, Núria</style></author><author><style face="normal" font="default" size="100%">Cristiani, Franco</style></author><author><style face="normal" font="default" size="100%">Floris, Costantino</style></author><author><style face="normal" font="default" size="100%">Lai, Simona</style></author><author><style face="normal" font="default" size="100%">Nurchi, Valeria Marina</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Copper(II) and nickel(II) uptake from aqueous solutions by cork wastes: a NMR and potentiometric study</style></title><secondary-title><style face="normal" font="default" size="100%">Polyhedron</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">copper</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Metal uptake</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Potentiometric titration</style></keyword><keyword><style  face="normal" font="default" size="100%">Solid state 13C MAS and CP-MAS NMR</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0277538702009579</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">21</style></volume><pages><style face="normal" font="default" size="100%">1363 - 1367</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Due to the increasing interest in the use of biomasses from agriculture as removing agents for heavy metals in waste effluents, we present here a joint potentiometric and 13C MAS and cross polarization-magic angle spinning NMR (CP-MAS NMR) study on cork interaction with Cu(II) and Ni(II). Through potentiometry we were able to distinguish two kind of interactions, a stronger one which involves protonated sites on cork and a second that allows hydroxide precipitation of the bound metal ion into the cork structure. NMR signal analysis suggests a specific metal complexation on the carbohydrate moieties of polymeric cork matrix. The 13C MAS NMR suggests that the dynamics in the MHz range and the overall arrangement of polymeric matrix is not affected by metal binding; and the spin relaxation times T1ρ(1H) and T1ρ(13C) show that no significant difference of relaxation processes in the KHz range is introduced by metal coordination.</style></abstract><issue><style face="normal" font="default" size="100%">14–15</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Villaescusa, Isabel</style></author><author><style face="normal" font="default" size="100%">Fiol, Núria</style></author><author><style face="normal" font="default" size="100%">Cristiani, Franco</style></author><author><style face="normal" font="default" size="100%">Floris, Costantino</style></author><author><style face="normal" font="default" size="100%">Lai, Simona</style></author><author><style face="normal" font="default" size="100%">Nurchi, Valeria Marina</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Copper(II) and nickel(II) uptake from aqueous solutions by cork wastes: a NMR and potentiometric study</style></title><secondary-title><style face="normal" font="default" size="100%">Polyhedron</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">copper</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Metal uptake</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Potentiometric titration</style></keyword><keyword><style  face="normal" font="default" size="100%">Solid state 13C MAS and CP-MAS NMR</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><volume><style face="normal" font="default" size="100%">21</style></volume><pages><style face="normal" font="default" size="100%">1363-1367</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Due to the increasing interest in the use of biomasses from agriculture as removing agents for heavy metals in waste effluents, we present here a joint potentiometric and 13C MAS and cross polarization-magic angle spinning NMR (CP-MAS NMR) study on cork interaction with Cu(II) and Ni(II). Through potentiometry we were able to distinguish two kind of interactions, a stronger one which involves protonated sites on cork and a second that allows hydroxide precipitation of the bound metal ion into the cork structure. NMR signal analysis suggests a specific metal complexation on the carbohydrate moieties of polymeric cork matrix. The 13C MAS NMR suggests that the dynamics in the MHz range and the overall arrangement of polymeric matrix is not affected by metal binding; and the spin relaxation times T1ρ(1H) and T1ρ(13C) show that no significant difference of relaxation processes in the KHz range is introduced by metal coordination.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Prasad, M N</style></author><author><style face="normal" font="default" size="100%">Freitas, H</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Removal of toxic metals from solution by leaf, stem and root phytomass of Quercus ilex L. (holly oak).</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental pollution (Barking, Essex : 1987)</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biosorption</style></keyword><keyword><style  face="normal" font="default" size="100%">cadmium</style></keyword><keyword><style  face="normal" font="default" size="100%">chromium</style></keyword><keyword><style  face="normal" font="default" size="100%">copper</style></keyword><keyword><style  face="normal" font="default" size="100%">desorption</style></keyword><keyword><style  face="normal" font="default" size="100%">lead</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">phytomass</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">root</style></keyword><keyword><style  face="normal" font="default" size="100%">stem</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year></dates><volume><style face="normal" font="default" size="100%">110</style></volume><pages><style face="normal" font="default" size="100%">277-283</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Increased consciousness for safeguarding the aqueous environment has prompted a search for alternative technologies for the removal of toxic metal ions from aqueous solutions. In this regard, a wide variety of biomass is being considered as adsorbents of heavy metals for treatment of industrial and domestic wastewaters as well as natural waters, including drinking water. In the present investigation, the potential of Quercus ilex phytomass from stem, leaf and root as an adsorbent of chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd) and lead (Pb) at ambient temperature was investigated. The metal uptake capacity of the root for different metals was found to be in the order: Ni&gt;Cd&gt;Pb&gt;Cu&gt;Cr; stem Ni&gt;Pb&gt;Cu&gt;Cd&gt;Cr; and leaf Ni&gt;Cd&gt;Cu&gt;Pb&gt;Cr. The highest amount adsorbed was Ni (root&gt;leaf&gt;stem). Data from this laboratory demonstrated that Ni is sequestered mostly in the roots, where concentrations can be as high as 428.4 ng/g dry wt., when 1-year-old seedlings were treated with Ni (2000 mg/l) in pot culture experiments, compared to 7.63 ng/g dry wt., control (garden and greenhouse soil) topsoil where Ni was present in trace amounts. This proves that the root biomass of Q. ilex has the capacity for complexing Ni. Cr exhibited the least adsorption values for all the three types of phytomass compared to other metals. The trend of adsorption of the phytomass was similar for Ni and Cd, i.e. root&gt;leaf&gt;stem. Desorption with 10 mM Na(4) EDTA was effective (55-90%) and, hence, there exists the possibility of recycling the phytomass. The biosorption results of recycled phytomass suggest that the selected adsorbents are re-usable. The advantages and potential of the Q. ilex phytomass as a biofilter of toxic trace metals, the scope and need for enhancing the efficiency of the Q. ilex phytomass as an adsorbent of metals are presented.</style></abstract><accession-num><style face="normal" font="default" size="100%">15092842</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Prasad, M. N.</style></author><author><style face="normal" font="default" size="100%">Freitas, H.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Removal of toxic metals from solution by leaf, stem and root phytomass of Quercus ilex L. (holly oak).</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental pollution (Barking, Essex : 1987)</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biosorption</style></keyword><keyword><style  face="normal" font="default" size="100%">cadmium</style></keyword><keyword><style  face="normal" font="default" size="100%">chromium</style></keyword><keyword><style  face="normal" font="default" size="100%">copper</style></keyword><keyword><style  face="normal" font="default" size="100%">desorption</style></keyword><keyword><style  face="normal" font="default" size="100%">lead</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">phytomass</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">root</style></keyword><keyword><style  face="normal" font="default" size="100%">stem</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/15092842</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">110</style></volume><pages><style face="normal" font="default" size="100%">277 - 283</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Increased consciousness for safeguarding the aqueous environment has prompted a search for alternative technologies for the removal of toxic metal ions from aqueous solutions. In this regard, a wide variety of biomass is being considered as adsorbents of heavy metals for treatment of industrial and domestic wastewaters as well as natural waters, including drinking water. In the present investigation, the potential of Quercus ilex phytomass from stem, leaf and root as an adsorbent of chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd) and lead (Pb) at ambient temperature was investigated. The metal uptake capacity of the root for different metals was found to be in the order: Ni&gt;Cd&gt;Pb&gt;Cu&gt;Cr; stem Ni&gt;Pb&gt;Cu&gt;Cd&gt;Cr; and leaf Ni&gt;Cd&gt;Cu&gt;Pb&gt;Cr. The highest amount adsorbed was Ni (root&gt;leaf&gt;stem). Data from this laboratory demonstrated that Ni is sequestered mostly in the roots, where concentrations can be as high as 428.4 ng/g dry wt., when 1-year-old seedlings were treated with Ni (2000 mg/l) in pot culture experiments, compared to 7.63 ng/g dry wt., control (garden and greenhouse soil) topsoil where Ni was present in trace amounts. This proves that the root biomass of Q. ilex has the capacity for complexing Ni. Cr exhibited the least adsorption values for all the three types of phytomass compared to other metals. The trend of adsorption of the phytomass was similar for Ni and Cd, i.e. root&gt;leaf&gt;stem. Desorption with 10 mM Na(4) EDTA was effective (55-90%) and, hence, there exists the possibility of recycling the phytomass. The biosorption results of recycled phytomass suggest that the selected adsorbents are re-usable. The advantages and potential of the Q. ilex phytomass as a biofilter of toxic trace metals, the scope and need for enhancing the efficiency of the Q. ilex phytomass as an adsorbent of metals are presented.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 15092842</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Nabais, C</style></author><author><style face="normal" font="default" size="100%">Freitas, H</style></author><author><style face="normal" font="default" size="100%">Hagemeyer, J</style></author><author><style face="normal" font="default" size="100%">Breckle, S W</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Radial distribution of Ni in stemwood of Quercus ilex L. trees grown on serpentine and sandy loam (umbric leptosol) soils of NE-Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Plant and soil</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">dendrochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Nickel</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">serpentine</style></keyword><keyword><style  face="normal" font="default" size="100%">tree rings</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><volume><style face="normal" font="default" size="100%">183</style></volume><pages><style face="normal" font="default" size="100%">181-185</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Concentrations of Ni were determined in xylem and phloem of Quercus ilex trees growing on serpentine and sandy loam soils of northeast Portugal. Radial distribution patterns of Ni in stemwood were compared to variations in annual growth increments of the trees. Concentrations of Ni in xylem and phloem were higher in Q. ilex from serpentine soil, when compared with Q. ilex of a sandy loam soil. The radial distributions of Ni showed large variations among the trees, although they all grew in the same area within a short distance from each other. These differences can be caused by small-scale spatial variations in the soil. Therefore, the use of such radial Ni distributions for a retrospective biomonitoring of the Ni pollution of larger areas appears questionable.</style></abstract></record></records></xml>