Thermodynamic Characterization of Humic Acid-surfactant Interaction: New Insights into the Characteristics and Structure of Humic Acids
| Title: | Thermodynamic Characterization of Humic Acid-surfactant Interaction: New Insights into the Characteristics and Structure of Humic Acids |
|---|---|
| Authors: | Leonardus Vergütz, Luis Henrique Mendes da Silva, Roberto Ferreira Novais, Maria do Carmo Hespanhol da Silva, Aparecida Barbosa Mageste, Ivo Ribeiro Silva |
| Source: | Revista Brasileira de Ciência do Solo, Vol 39, Iss 6, Pp 1633-1642 (2015) |
| Publisher Information: | Sociedade Brasileira de Ciência do Solo, 2015. |
| Publication Year: | 2015 |
| Collection: | LCC:Agriculture (General) |
| Subject Terms: | entalpia, substâncias húmicas, titulação calorimétrica isotérmica, estrutura macromolecular, microcalorimetria, estrutura supramolecular, Agriculture (General), S1-972 |
| More Details: | ABSTRACT Humic acids (HA) are a component of humic substances (HS), which are found in nearly all soils, sediments, and waters. They play a key role in many, if not most, chemical and physical properties in their environment. Despite the importance of HA, their high complexity makes them a poorly understood system. Therefore, understanding the physicochemical properties and interactions of HA is crucial for determining their fundamental role and obtaining structural details. Cationic surfactants are known to interact electrostatically and hydrophobically with HA. Because they are a very well-known and characterized system, they offer a good choice as molecular probes for studying HA. The objective of this study was to evaluate the interaction between cationic surfactants and HA through isothermal titration calorimetry in a thermodynamic manner, aiming to obtain information about the basic structure of HA, the nature of this interaction, and if HA from different origins show different basic structures. Contrary to what the supramolecular model asserts, HA structure is not loosely held, though it may separate depending on the conditions the HA are subjected to in their milieu. It did not show any division or conformational change when interacting with surfactants. The basic structure of the HA remains virtually the same regardless of the different sources and compositions of these HA. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 1806-9657 01000683 |
| Relation: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000601633&lng=en&tlng=en; https://doaj.org/toc/1806-9657 |
| DOI: | 10.1590/01000683rbcs20140258 |
| Access URL: | https://doaj.org/article/88172e78636c466a836f51426fce8cb3 |
| Accession Number: | edsdoj.88172e78636c466a836f51426fce8cb3 |
| Database: | Directory of Open Access Journals |
| ISSN: | 18069657 01000683 |
|---|---|
| DOI: | 10.1590/01000683rbcs20140258 |
| Published in: | Revista Brasileira de Ciência do Solo |
| Language: | English |