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Manuel Ariasestevez - One of the best experts on this subject based on the ideXlab platform.
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competitive adsorption desorption of tetracycline oxytetracycline and chlortetracycline on two acid soils stirred Flow Chamber experiments
Chemosphere, 2015Co-Authors: David Fernandezcalvino, Alipio Bermudezcouso, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, Avelino NunezdelgadoAbstract:The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred Flow Chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments.
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pine bark as bio adsorbent for cd cu ni pb and zn batch type and stirred Flow Chamber experiments
Journal of Environmental Management, 2014Co-Authors: Laura Cutillasbarreiro, David Fernandezcalvino, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, L Ansiasmanso, Avelino NunezdelgadoAbstract:The objective of this work was to determine the retention of five metals on pine bark using stirred Flow and batch-type experiments. Resulting from batch-type kinetic experiments, adsorption was rapid, with no significant differences for the various contact times. Adsorption was between 98 and 99% for Pb(2+), 83-84% for Cu(2+), 78-84% for Cd(2+), 77-83% for Zn(2+), and 70-75% for Ni(2+), and it was faster for low concentrations, with Pb suffering the highest retention, followed by Cu, Cd, Ni and Zn. The fitting to the Freundlich and Langmuir models was satisfactory. Desorption increased in parallel to the added concentrations, with Pb always showing the lowest levels. Stirred Flow Chamber experiments showed strong hysteresis for Pb and Cu, sorption being mostly irreversible. The differences affecting the studied heavy metals are mainly due to different affinity for the adsorption sites. Pine bark can be used to effectively remove Pb and Cu from polluted environments.
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comparison of batch stirred Flow Chamber and column experiments to study adsorption desorption and transport of carbofuran within two acidic soils
Chemosphere, 2012Co-Authors: Alipio Bermudezcouso, David Fernandezcalvino, Isabel Rodriguezsalgado, Juan Carlos Novoamunoz, Manuel AriasestevezAbstract:Different methods (batch, column and stirred Flow Chamber experiments) used for adsorption and desorption of carbofuran studies were compared. All tested methods showed that the carbofuran adsorption was higher in the soil with the higher organic matter content, whereas the opposite behaviour was observed for the percentage of carbofuran desorbed. However, different methods have revealed some discrepancies in carbofuran adsorption/desorption kinetics. Although batch method showed interesting data on equilibrium experiments, such as a low heterogeneity for the carbofuran adsorption sites independent of soil organic matter content, it had some disadvantages for carbofuran adsorption/desorption kinetic studies. The disadvantages were related with the excessive limitations of this method on kinetics, i.e., no difference could be detected between different soils. However, with column and stirred Flow Chamber methods the carbofuran adsorption/desorption kinetics of different soils could be compared. Moreover, the absolute values of carbofuran adsorption/desorption and its rate were higher in the stirred Flow Chamber than in the batch and column experiments. Using stirred Flow Chamber experiments the carbofuran desorption was significantly faster than its adsorption, whereas carbofuran using column experiments they were similar. These discrepancies should be considered when the results obtained only with one method is discussed.
Avelino Nunezdelgado - One of the best experts on this subject based on the ideXlab platform.
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competitive adsorption desorption of tetracycline oxytetracycline and chlortetracycline on two acid soils stirred Flow Chamber experiments
Chemosphere, 2015Co-Authors: David Fernandezcalvino, Alipio Bermudezcouso, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, Avelino NunezdelgadoAbstract:The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred Flow Chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments.
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pine bark as bio adsorbent for cd cu ni pb and zn batch type and stirred Flow Chamber experiments
Journal of Environmental Management, 2014Co-Authors: Laura Cutillasbarreiro, David Fernandezcalvino, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, L Ansiasmanso, Avelino NunezdelgadoAbstract:The objective of this work was to determine the retention of five metals on pine bark using stirred Flow and batch-type experiments. Resulting from batch-type kinetic experiments, adsorption was rapid, with no significant differences for the various contact times. Adsorption was between 98 and 99% for Pb(2+), 83-84% for Cu(2+), 78-84% for Cd(2+), 77-83% for Zn(2+), and 70-75% for Ni(2+), and it was faster for low concentrations, with Pb suffering the highest retention, followed by Cu, Cd, Ni and Zn. The fitting to the Freundlich and Langmuir models was satisfactory. Desorption increased in parallel to the added concentrations, with Pb always showing the lowest levels. Stirred Flow Chamber experiments showed strong hysteresis for Pb and Cu, sorption being mostly irreversible. The differences affecting the studied heavy metals are mainly due to different affinity for the adsorption sites. Pine bark can be used to effectively remove Pb and Cu from polluted environments.
Shu Chien - One of the best experts on this subject based on the ideXlab platform.
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Low viscosity Ektacytometry and its validation tested by Flow Chamber
Journal of biomechanics, 2001Co-Authors: Weijuan Yao, Zongyao Wen, Zongyi Yan, Dagong Sun, Lide Xie, Shu ChienAbstract:Abstract The Flow Chamber was used to observe the orientation and small deformation of red blood cells (RBCs) in a shear Flow of low viscosity. With the aid of computer software, the percentage of RBCs oriented to the C =0 orbit (OI) F and the degree of deformation (DI) F of such RBCs were calculated by processing the photographs. It was found that these parameters were highly correlated, respectively, to the orientation index (OI) E and the small deformation index (DI) E obtained by our low viscosity Ektacytometry (LVE). Thus, our Flow Chamber research has provided direct evidence to validate the use of this low viscosity Ektacytometry. Although there are relative merits for the Flow Chamber method using low viscosity medium, the LVE is more likely to be applied in clinic for its simpleness and convenience.
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Technical note Low viscosity Ektacytometry and its validation tested by Flow Chamber
2001Co-Authors: Weijuan Yao, Zongyao Wen, Zongyi Yan, Dagong Sun, Lide Xie, Shu ChienAbstract:The Flow Chamber was used to observe the orientation and small deformation of red blood cells (RBCs) in a shear Flow of low viscosity. With the aid of computer software, the percentage of RBCs oriented to the C ¼ 0 orbit ðOIÞF and the degree of deformation ðDIÞF of such RBCs were calculated by processing the photographs. It was found that these parameters were highly correlated, respectively, to the orientation index ðOIÞE and the small deformation index ðDIÞE obtained by our low viscosity Ektacytometry (LVE). Thus, our Flow Chamber research has provided direct evidence to validate the use of this low viscosity Ektacytometry. Although there are relative merits for the Flow Chamber method using low viscosity medium, the LVE is more likely to be applied in clinic for its simpleness and convenience. r 2001 Elsevier Science Ltd. All rights reserved.
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Design and construction of a linear shear stress Flow Chamber
Annals of biomedical engineering, 1993Co-Authors: S. Usami, Shu Chien, Hsuan-hsu Chen, Yihua Zhao, Richard SkalakAbstract:A new paralle plate Flow Chamber that has a linear variation of shear stress, starting from a predetermined maximum value at the entrance and falling to zero at the exit, has been designed and tested. This is in contrast to the usual rect-angular channel plan which produces a constant shear stress over the entire length. The new design is based on the theory of Hele-Shaw Flow between parallel plates. To verify the efficacy of the Flow channel, the effect of fluid shear stress on platelet adhesion to a fibrinogen-coated glass surface was tested. The percentage of attached platelets after 5 min of shear stress is shown to be a function of shear stress. With this new Flow Chamber, cell-cell interactions can be studied efficiently over a wide range of shear stress using a single run at constant discharge.
David Fernandezcalvino - One of the best experts on this subject based on the ideXlab platform.
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competitive adsorption desorption of tetracycline oxytetracycline and chlortetracycline on two acid soils stirred Flow Chamber experiments
Chemosphere, 2015Co-Authors: David Fernandezcalvino, Alipio Bermudezcouso, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, Avelino NunezdelgadoAbstract:The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred Flow Chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments.
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pine bark as bio adsorbent for cd cu ni pb and zn batch type and stirred Flow Chamber experiments
Journal of Environmental Management, 2014Co-Authors: Laura Cutillasbarreiro, David Fernandezcalvino, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, L Ansiasmanso, Avelino NunezdelgadoAbstract:The objective of this work was to determine the retention of five metals on pine bark using stirred Flow and batch-type experiments. Resulting from batch-type kinetic experiments, adsorption was rapid, with no significant differences for the various contact times. Adsorption was between 98 and 99% for Pb(2+), 83-84% for Cu(2+), 78-84% for Cd(2+), 77-83% for Zn(2+), and 70-75% for Ni(2+), and it was faster for low concentrations, with Pb suffering the highest retention, followed by Cu, Cd, Ni and Zn. The fitting to the Freundlich and Langmuir models was satisfactory. Desorption increased in parallel to the added concentrations, with Pb always showing the lowest levels. Stirred Flow Chamber experiments showed strong hysteresis for Pb and Cu, sorption being mostly irreversible. The differences affecting the studied heavy metals are mainly due to different affinity for the adsorption sites. Pine bark can be used to effectively remove Pb and Cu from polluted environments.
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comparison of batch stirred Flow Chamber and column experiments to study adsorption desorption and transport of carbofuran within two acidic soils
Chemosphere, 2012Co-Authors: Alipio Bermudezcouso, David Fernandezcalvino, Isabel Rodriguezsalgado, Juan Carlos Novoamunoz, Manuel AriasestevezAbstract:Different methods (batch, column and stirred Flow Chamber experiments) used for adsorption and desorption of carbofuran studies were compared. All tested methods showed that the carbofuran adsorption was higher in the soil with the higher organic matter content, whereas the opposite behaviour was observed for the percentage of carbofuran desorbed. However, different methods have revealed some discrepancies in carbofuran adsorption/desorption kinetics. Although batch method showed interesting data on equilibrium experiments, such as a low heterogeneity for the carbofuran adsorption sites independent of soil organic matter content, it had some disadvantages for carbofuran adsorption/desorption kinetic studies. The disadvantages were related with the excessive limitations of this method on kinetics, i.e., no difference could be detected between different soils. However, with column and stirred Flow Chamber methods the carbofuran adsorption/desorption kinetics of different soils could be compared. Moreover, the absolute values of carbofuran adsorption/desorption and its rate were higher in the stirred Flow Chamber than in the batch and column experiments. Using stirred Flow Chamber experiments the carbofuran desorption was significantly faster than its adsorption, whereas carbofuran using column experiments they were similar. These discrepancies should be considered when the results obtained only with one method is discussed.
Juan Carlos Novoamunoz - One of the best experts on this subject based on the ideXlab platform.
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competitive adsorption desorption of tetracycline oxytetracycline and chlortetracycline on two acid soils stirred Flow Chamber experiments
Chemosphere, 2015Co-Authors: David Fernandezcalvino, Alipio Bermudezcouso, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, Avelino NunezdelgadoAbstract:The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred Flow Chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments.
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pine bark as bio adsorbent for cd cu ni pb and zn batch type and stirred Flow Chamber experiments
Journal of Environmental Management, 2014Co-Authors: Laura Cutillasbarreiro, David Fernandezcalvino, Juan Carlos Novoamunoz, Manuel Ariasestevez, Maria J Fernandezsanjurjo, Esperanza Alvarezrodriguez, L Ansiasmanso, Avelino NunezdelgadoAbstract:The objective of this work was to determine the retention of five metals on pine bark using stirred Flow and batch-type experiments. Resulting from batch-type kinetic experiments, adsorption was rapid, with no significant differences for the various contact times. Adsorption was between 98 and 99% for Pb(2+), 83-84% for Cu(2+), 78-84% for Cd(2+), 77-83% for Zn(2+), and 70-75% for Ni(2+), and it was faster for low concentrations, with Pb suffering the highest retention, followed by Cu, Cd, Ni and Zn. The fitting to the Freundlich and Langmuir models was satisfactory. Desorption increased in parallel to the added concentrations, with Pb always showing the lowest levels. Stirred Flow Chamber experiments showed strong hysteresis for Pb and Cu, sorption being mostly irreversible. The differences affecting the studied heavy metals are mainly due to different affinity for the adsorption sites. Pine bark can be used to effectively remove Pb and Cu from polluted environments.
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comparison of batch stirred Flow Chamber and column experiments to study adsorption desorption and transport of carbofuran within two acidic soils
Chemosphere, 2012Co-Authors: Alipio Bermudezcouso, David Fernandezcalvino, Isabel Rodriguezsalgado, Juan Carlos Novoamunoz, Manuel AriasestevezAbstract:Different methods (batch, column and stirred Flow Chamber experiments) used for adsorption and desorption of carbofuran studies were compared. All tested methods showed that the carbofuran adsorption was higher in the soil with the higher organic matter content, whereas the opposite behaviour was observed for the percentage of carbofuran desorbed. However, different methods have revealed some discrepancies in carbofuran adsorption/desorption kinetics. Although batch method showed interesting data on equilibrium experiments, such as a low heterogeneity for the carbofuran adsorption sites independent of soil organic matter content, it had some disadvantages for carbofuran adsorption/desorption kinetic studies. The disadvantages were related with the excessive limitations of this method on kinetics, i.e., no difference could be detected between different soils. However, with column and stirred Flow Chamber methods the carbofuran adsorption/desorption kinetics of different soils could be compared. Moreover, the absolute values of carbofuran adsorption/desorption and its rate were higher in the stirred Flow Chamber than in the batch and column experiments. Using stirred Flow Chamber experiments the carbofuran desorption was significantly faster than its adsorption, whereas carbofuran using column experiments they were similar. These discrepancies should be considered when the results obtained only with one method is discussed.