Abstract
Chitosan (Ch), vermiculite (V) and lignin (L) were used as the components of a natural composite adsorbent (Ch-VL) for the removal of the UO
ions in aqueous solutions. During the study, we recorded and analyzed the initial UO
ion concentration, initial pH, contact time, temperature, and recovery. The recycling performance of the Ch-VL composite was assessed by three sequential adsorption/desorption experiments. Adsorption performance of the Ch-VL composite for UO
ions was 600 mg L
at pH 4.5 and temperature of 25 °C. Thermodynamic findings, ΔH
:28.1 kJ mol
, and ΔG
:-14.1 kJ mol
showed that adsorption behavior was endothermic and spontaneous. Its maximum adsorption capacity was 0.322 mol kg
, obtained from the Langmuir isotherm model. The adsorption kinetics indicated that it followed the pseudo-second-order and intraparticle diffusion rate kinetics. The adsorption thermodynamic shown indicated that the UO
ion adsorption was both spontaneous and endothermic. The adsorption process was enlightened by FT-IR and SEM-EDX analyses. The study suggested a simple and cost-effective approach for the removal of toxic UO
ions from wastewater. To highlight the adsorption mechanism, DFT calculations were performed. Theoretical results are in good agreement with experimental observations.