Aggregation kinetics of humic acids in the presence of calcium ions
The aggregation kinetics of a humic acid (HA) sample as a function of Ca2+ concentration at pH 5, 7 and 9 was investigated. UV–VIS spectroscopy was employed to quantify the progress of the aggregation reaction, and electrophoresis was used to evaluate the zeta potential of the HA molecules. The aggr...
| Main Authors: | , , , |
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| Format: | Artículo |
| Language: | Inglés |
| Published: |
2017
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| Online Access: | http://hdl.handle.net/20.500.12123/1281 http://www.sciencedirect.com/science/article/pii/S0927775713002197 https://doi.org/10.1016/j.colsurfa.2013.03.030 |
| _version_ | 1855482860494913536 |
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| author | Kloster, Nanci Soledad Brigante, Maximiliano Eduardo Zanini, Graciela Pilar Avena, Marcelo Javier |
| author_browse | Avena, Marcelo Javier Brigante, Maximiliano Eduardo Kloster, Nanci Soledad Zanini, Graciela Pilar |
| author_facet | Kloster, Nanci Soledad Brigante, Maximiliano Eduardo Zanini, Graciela Pilar Avena, Marcelo Javier |
| author_sort | Kloster, Nanci Soledad |
| collection | INTA Digital |
| description | The aggregation kinetics of a humic acid (HA) sample as a function of Ca2+ concentration at pH 5, 7 and 9 was investigated. UV–VIS spectroscopy was employed to quantify the progress of the aggregation reaction, and electrophoresis was used to evaluate the zeta potential of the HA molecules. The aggregation rate increases significantly by increasing Ca2+ concentration at all investigated pH, being higher at pH 9 than at pH 5 and 7. An aggregation mechanism is proposed, which consists of at least two steps: a rapid binding of Ca2+ to humic molecules, followed by a slower process where HA molecules approach each other and become aggregated. This aggregation is possible because Ca2+ binding decreases the zeta potential of HA from −37 mV to −15 mV and because it is able to form bridges between HA molecules. There is no molecular fractionation up to 60% of aggregation. Above this value, HA aggregates become enriched with more aromatic HA molecules. The fast aggregation of HA in the presence of calcium ions implies that aggregates may temporarily trap, protect and transport pollutants in the environment. |
| format | Artículo |
| id | INTA1281 |
| institution | Instituto Nacional de Tecnología Agropecuaria (INTA -Argentina) |
| language | Inglés |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| record_format | dspace |
| spelling | INTA12812018-06-26T17:25:22Z Aggregation kinetics of humic acids in the presence of calcium ions Kloster, Nanci Soledad Brigante, Maximiliano Eduardo Zanini, Graciela Pilar Avena, Marcelo Javier Suelo Soil Calcium Ions Humic Acids Flocculation Calcio Iones Acido Húmico Floculación Cinética Agregación Iones de Calcio Coagulation Kinetics Aggregation Mechanism Calcium Ions The aggregation kinetics of a humic acid (HA) sample as a function of Ca2+ concentration at pH 5, 7 and 9 was investigated. UV–VIS spectroscopy was employed to quantify the progress of the aggregation reaction, and electrophoresis was used to evaluate the zeta potential of the HA molecules. The aggregation rate increases significantly by increasing Ca2+ concentration at all investigated pH, being higher at pH 9 than at pH 5 and 7. An aggregation mechanism is proposed, which consists of at least two steps: a rapid binding of Ca2+ to humic molecules, followed by a slower process where HA molecules approach each other and become aggregated. This aggregation is possible because Ca2+ binding decreases the zeta potential of HA from −37 mV to −15 mV and because it is able to form bridges between HA molecules. There is no molecular fractionation up to 60% of aggregation. Above this value, HA aggregates become enriched with more aromatic HA molecules. The fast aggregation of HA in the presence of calcium ions implies that aggregates may temporarily trap, protect and transport pollutants in the environment. Fil: Kloster, Nanci Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina Fil: Brigante, Maximiliano Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina Fil: Zanini, Graciela Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina Fil: Avena, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina 2017-09-21T13:18:30Z 2017-09-21T13:18:30Z 2013 info:ar-repo/semantics/artículo info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://hdl.handle.net/20.500.12123/1281 http://www.sciencedirect.com/science/article/pii/S0927775713002197 0927-7757 https://doi.org/10.1016/j.colsurfa.2013.03.030 eng info:eu-repo/semantics/restrictedAccess application/pdf Colloids and surfaces. A: Physicochemical and engineering aspects 427 : 76-82. (2015). |
| spellingShingle | Suelo Soil Calcium Ions Humic Acids Flocculation Calcio Iones Acido Húmico Floculación Cinética Agregación Iones de Calcio Coagulation Kinetics Aggregation Mechanism Calcium Ions Kloster, Nanci Soledad Brigante, Maximiliano Eduardo Zanini, Graciela Pilar Avena, Marcelo Javier Aggregation kinetics of humic acids in the presence of calcium ions |
| title | Aggregation kinetics of humic acids in the presence of calcium ions |
| title_full | Aggregation kinetics of humic acids in the presence of calcium ions |
| title_fullStr | Aggregation kinetics of humic acids in the presence of calcium ions |
| title_full_unstemmed | Aggregation kinetics of humic acids in the presence of calcium ions |
| title_short | Aggregation kinetics of humic acids in the presence of calcium ions |
| title_sort | aggregation kinetics of humic acids in the presence of calcium ions |
| topic | Suelo Soil Calcium Ions Humic Acids Flocculation Calcio Iones Acido Húmico Floculación Cinética Agregación Iones de Calcio Coagulation Kinetics Aggregation Mechanism Calcium Ions |
| url | http://hdl.handle.net/20.500.12123/1281 http://www.sciencedirect.com/science/article/pii/S0927775713002197 https://doi.org/10.1016/j.colsurfa.2013.03.030 |
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