| Title: | Comparison of Surface Properties of Sepiolite and Palygorskite: Surface Energy and Nanoroughness |
| Author(s): | Almeida R; Ferraz E; Santaren J; Gamelas JAF; |
| Address: | "CIEPQPF-Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Rua Silvio Lima, Polo II, PT-3030-790 Coimbra, Portugal. Techn&Art, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, PT-2300-313 Tomar, Portugal. Geobiotec, Geosciences Department, Campus Universitario de Santiago, University of Aveiro, PT-3810-193 Aveiro, Portugal. Tolsa, SA, Research & Technology for New Businesses, Ctra. de Madrid a Rivas Jarama, 35, ES-28031 Madrid, Spain" |
| ISSN/ISBN: | 2079-4991 (Print) 2079-4991 (Electronic) 2079-4991 (Linking) |
| Abstract: | "The surface properties of two sepiolite samples and one palygorskite sample were compared using inverse gas chromatography (IGC). Samples were previously conditioned at appropriate temperatures for the removal of all zeolitic water. Dispersive (or Lifshitz-van der Waals) component of the surface energy (gamma(s)(d)), specific interactions (-DeltaG(a)(s)) with pi electron donor bases (1-alkenes), and nanomorphology indices (IMchiT) based on the injections of cycloalkanes and a branched alkane were measured. From IGC data, at 240 degrees C, it was found that the palygorskite was clearly distinguished from the sepiolites. The palygorskite possessed a lower gamma(s)(d), larger -DeltaG(a)(s) with 1-alkenes, and remarkably higher IMchiT. Slight differences could also be observed between the two sepiolite samples with the same origin. The results were rationalized in terms of the structural features of the two studied minerals. The larger channels of the sepiolite allow for a better insertion of the n-alkanes (longer retention times) while excluding the bulkier probes, such as cyclooctane or 2,2,4-trimethylpentane. Accordingly, the corresponding gamma(s)(d) values were larger and the IMchiT values were lower (higher surface nanoroughness) for the sepiolites. Regarding Lewis acid-base properties, all the sample's surfaces evidenced a very strong amphoteric character. The present results highlight the potential of the evaluated samples for, e.g., adsorption processes with volatile organic compounds or matrix-filler interactions regarding the production of composite structures with Lewis acid-base matrices" |
| Keywords: | adsorption aluminosilicate attapulgite clay minerals fibrous minerals inverse gas chromatography; |
| Notes: | "PubMed-not-MEDLINEAlmeida, Ricardo Ferraz, Eduardo Santaren, Julio Gamelas, Jose A F eng CENTRO 01-0145-FEDER-031884/Fundacao para a Ciencia e a Tecnologia/ CENTRO 01-0145-FEDER-031884/Programa Operacional Regional do Centro/ Switzerland 2021/07/03 Nanomaterials (Basel). 2021 Jun 16; 11(6):1579. doi: 10.3390/nano11061579" |
