Synthesis and characterization of chitosan-vermiculite-lignin ternary composite as an adsorbent for effective removal of uranyl ions from aqueous solution: Experimental and theoretical analyses

• Published in: International journal of biological macromolecules Vol. 209; no. Pt A; pp. 1234 - 1247
• Main Authors: Şenol, Zeynep Mine, Kaya, Savaş, Şimşek, Selçuk, Katin, K.P., Özer, Ali, Marzouki, Riadh
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2022
• Subjects: Adsorption; Chitosan; DFT calculations; Lignin; Ternary composite; Uranyl; Vermiculite; Lignin; Adsorption; Ternary composite; Vermiculite; Chitosan; Uranyl; DFT calculations
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2022.04.128

Chitosan (Ch), vermiculite (V) and lignin (L) were used as the components of a natural composite adsorbent (Ch-VL) for the removal of the UO22+ ions in aqueous solutions. During the study, we recorded and analyzed the initial UO22+ 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 UO22+ ions was 600 mg L−1 at pH 4.5 and temperature of 25 °C. Thermodynamic findings, ΔH0:28.1 kJ mol−1, and ΔG0:−14.1 kJ mol−1 showed that adsorption behavior was endothermic and spontaneous. Its maximum adsorption capacity was 0.322 mol kg−1, 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 UO22+ 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 UO22+ ions from wastewater. To highlight the adsorption mechanism, DFT calculations were performed. Theoretical results are in good agreement with experimental observations.