Thallium Removal from Aqueous Solutions Using L Zeolite: Structural Modifications, Cation Distribution and Water Network Reorganisation

first_pagesettingsOrder Article Reprints Open AccessArticle Thallium Removal from Aqueous Solutions Using L Zeolite: Structural Modifications, Cation Distribution and Water Network Reorganisation by Luca Adami 1,*ORCID,Maura Mancinelli 1ORCID,Francesco Di Benedetto 1ORCID,Renzo Tassinari 1ORCID,Matteo Alberghini 2ORCID,Giacomo Ferretti 3ORCID andAnnalisa Martucci 1,*ORCID 1 Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1, 44122 Ferrara, Italy 2 Department of Environmental and Prevention Sciences, University of Ferrara, Via Borsari 46, 44121 Ferrara, Italy 3 Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Borsari 46, 44121 Ferrara, Italy * Authors to whom correspondence should be addressed. Molecules 2026, 31(12), 2130; https://doi.org/10.3390/molecules31122130 (registering DOI) Submission received: 17 May 2026 / Revised: 15 June 2026 / Accepted: 15 June 2026 / Published: 17 June 2026 (This article belongs to the Special Issue Green Chemistry Approaches to Analysis and Environmental Remediation—2nd Edition) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract This study investigates potassium-L zeolite (K-L) as an adsorbent for the removal of thallium (Tl+) from aqueous solutions, focusing on the relationship between cation exchange and framework structural response. X-ray powder diffraction (XRPD), thermal analysis, and Rietveld refinements were employed to monitor structural modifications upon Tl+ uptake, combined with batch adsorption experiments to evaluate the removal performance. At low Tl+ uptake, only minor structural perturbations occur, mainly involving slight shifts in extra-framework cation positions and limited rearrangement of channel water molecules. At higher Tl+ concentrations, a measurable anisotropic expansion of the zeolite framework is observed, consistent with partial substitution of K+ by Tl+ and progressive modification of the hydration environment within the pores. Moreover, the crystallographic distribution of Tl+ differs from that of the original K+ cations, suggesting a specific site preference during the uptake process. Batch experiments reveal rapid uptake kinetics, with equilibrium reached within minutes, and high removal efficiency up to 99.5%. The adsorption behaviour is well described by the Langmuir model, with a maximum adsorption capacity of 631 mg g−1. These findings highlight the coupling between ion exchange and structural flexibility in K-L zeolite and support its potential application for efficient thallium removal from contaminated water.