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Interfacial and rheological properties of humic acid/hematite suspensions.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ramos-Tejada, María Del Mar Ontiveros, Alfonso Viota, Julián López Duran, J. D. Garcia |
| Copyright Year | 2003 |
| Abstract | This work deals with the effect of humic acid (HA) adsorption on the interfacial properties, the stability, and the rheology of aqueous iron oxide (hematite) suspensions. It is first of all demonstrated that HA effectively adsorbs onto hematite, mainly at acid pH. Since the charge of the HA chains is negative, it will be electrostatically attracted to the hematite surface below the point of zero charge of the particles, when they are positively charged. Electrophoresis measurements of hematite suspensions as a function of pH in the presence and absence of HA clearly demonstrate the adsorption of negatively charged entities on the oxide. Since the HA-covered particles can be thought of as "soft" colloids, Ohshima's theory was used to gain information on the surface potential and the charge density of the HA layer (H. Ohshima, in: A.V. Delgado (Ed.), Interfacial Electrokinetics and Electrophoresis, Dekker, New York, 2002, p. 123). A different procedure was also used to ascertain the degree of modification experienced by the hematite surface when placed in contact with HA solutions. The contact angles of selected liquids on pretreated hematite layers lead to the conclusion that the humic acid molecules impart to the particles a significant electron-donor character, in turn increasing their hydrophilicity. All this amount of information is used in the work for the interpretation of the rheological properties of hematite suspensions; the results are consistent with a stabilizing effect of HA adsorption on the suspensions, mainly as a consequence of the increased electrostatic repulsion between particles. |
| Starting Page | 85 |
| Ending Page | 95 |
| Page Count | 11 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://hera.ugr.es/doi/15075217.pdf |
| PubMed reference number | 14611777v1 |
| Volume Number | 268 |
| Issue Number | 1 |
| Journal | Journal of colloid and interface science |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Arabic numeral 0 Charge (electrical) Colloids Cryonic Suspension Electrophoresis Humic Acids Isoelectric Point Liquid substance Particle Solutions Suspensions Unstable Medical Device Problem anatomical layer ferric oxide hematite |
| Content Type | Text |
| Resource Type | Article |
