Dissolution of nano-size Mg-Al-Cl hydrotalcite in aqueous media
Aqueous dissolution of a synthetic chloride-containing Mg2+-Al3+ layered double hydroxide was studied at 298K as a function of pH. Mild acidification (final pH 9 -5) results in incongruent dissolution of Mg2+, exclusively. Formation of an amorphous Al(OH)3 passive layer prevents further Mg2+ leachin...
| Authors: | , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2011 |
| Country: | Argentina |
| Institution: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repository: | CONICET Digital (CONICET) |
| Language: | English |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/68954 |
| Online Access: | http://hdl.handle.net/11336/68954 |
| Access Level: | Open access |
| Keyword: | Dissolution Kinetics Hydrotalcite Layered Double Hydroxide https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Summary: | Aqueous dissolution of a synthetic chloride-containing Mg2+-Al3+ layered double hydroxide was studied at 298K as a function of pH. Mild acidification (final pH 9 -5) results in incongruent dissolution of Mg2+, exclusively. Formation of an amorphous Al(OH)3 passive layer prevents further Mg2+ leaching, thus dissolved Mg2+ amounts for only 20% of the solid. At lower pH values, massive dissolution readily takes place in a congruent fashion. Congruent dissolution profiles are accounted for by a contracting volume kinetic law. The pH dependence of the observed rate constant shows that the kinetic order on proton concentration is 0.41, indicating that dissolution is surface controlled. The implications of these findings are discussed. |
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