TITLE:
Correlation between Surface OH− Groups and Fractal Dimensions of Synthetic Boehmite, Goethite, and Manganite: Insights into Their Physical-Adsorbent Properties
AUTHORS:
Francisco Granados-Correa, Melania Jiménez-Reyes
KEYWORDS:
Oxyhydroxides, Synthesis, Characterization, Surface Fractal Dimensions, Surface Hydroxyl Groups
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.13 No.4,
July
4,
2025
ABSTRACT: The oxyhydroxides boehmite, goethite, and manganite were synthesized, and their structure, texture, and morphology features were determined by different analytical techniques. Content of surface hydroxyl groups and zero point of charge (pHzpc) were measured by potentiometry, and the surface fractal dimension (Df) values were obtained through adsorption-desorption N2 isotherms and the Pfeifer and Cole method. The synthesized materials resulted crystalline, mesoporous, pure, and thermally stable, exhibiting high surface areas, between 188 and 413 m2/g. The pHzpc values were 9.2, 12.4, and 2.2 and surface hydroxyl group contents were for 1.16, 1.7, and 0.855 meq OH−/g, for boehmite, goethite, and manganite, respectively. Surface fractal dimensions were 1.5, 1.7, and 1.4 for boehmite, goethite and manganite, respectively, denoting relatively smooth surfaces. Surface hydroxyl group content linearly correlated with Df values. Characterization of these oxyhydroxides is valuable for several physicochemical adsorption processes of contaminants present in aqueous media.