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Greece is considered a diversity center for the genus Trifolium L. (Fabaceae), which is represented in the country by 95 taxa. However, the classification of the genus may vary according to different taxonomic approaches. The current study aims to contribute to the study of the genus by describing the seed coat surface of 23 Trifolium taxa that were collected in various localities of southern Greece. The seeds were obtained from herbarium specimens and observed with Scanning Electron Microscope. [ABSTRACT FROM AUTHOR]

Abstract: The adsorption of humic acid on bentonite from Milos Island (Greece) acid-treated with dilute H2SO4 solutions over a concentration range between 0.25 and 13M has been studied. Bentonite activated with 3M sulfuric acid (AAS) showed a higher efficiency in removing humic acid from aqueous solutions and was selected for further investigation. The specific surface area of acid-activated bentonite was estimated using the methylene blue adsorption method. The morphology of untreated, activated, and HA-sorbed bentonite was studied under scanning electron microscope (SEM). The effects of contact time, adsorbate concentration, adsorbent dose, and temperature on the adsorption of humic acid onto bentonite activated with 3M H2SO4 were studied using a batch adsorption technique. Acidic pH and high ionic strength proved to be favorable for the adsorption efficiency. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to describe the kinetic data and the rate constants were evaluated. The experimental isotherm data were analyzed using Langmuir, Freundlich, and Temkin equations and the isotherm constants were determined. Thermodynamic parameters (ΔH o, ΔS o, and ΔG o) of adsorption of humic acid onto acid-activated bentonite with 3M sulfuric acid were also evaluated. [Copyright &y& Elsevier]