The adsorption properties of the corm tunic structure of Crocus (Iridaceae) and its use as a biomarker for the environmental concentration of uranium

Abstract

In this study, we investigated whether the corm tunic structure, which is the underground part of the Crocus (Iridaceae) plant, can be used for adsorption and recovery/removal of uranium from an aqueous solution. The characterization of this structure, which has not been studied for its interaction with metals before, has been elucidated by point zero charge (PZC), FTIR, and SEM analyses. Extensive investigations were conducted on the adsorption properties of the biomass used and the pH, temperature, time, adsorbent dosage, and uranyl ion concentration variables were optimized. The experimental data were interpreted using theoretical adsorption models. The Langmuir model revealed a maximum adsorption capacity of the material to be 0.286 mol kg−1. Adsorption kinetics were also described using pseudo-first order, pseudo-second order, Elovich, and intra-particular diffusion models. It is shown that the adsorption pH reaches the highest adsorption at the natural pH of the uranium solution. Experimental studies showed that the adsorption was endothermic and spontaneous. It has been shown that this biomaterial can be used as an adsorbent for the removal of uranium as well as a biomarker for determining the environmental uranium concentration.