121st General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code PHYS.P-86
Subject Cesium Adsorption on Illite Surface: Molecular Dynamic Simulation
Authors Woohyeon Baek
Department of Chemistry, Kyungpook National University, Korea
Abstract The after treatment of contaminated water with radiogenic isotope is one of environmentally important problems in worldwide. The micaceous aluminosilicate minerals is one of effective materials that manipulates the mobility of radiogenic cations in hydrosphere system because of distinctive structure. The general structure consists of one layer of octahedron alumina between two layers of 6-membered tetrahedron silica ring which act as framework and cations inserted in center of 6-membered ring for charge balance. Among these minerals, illite has a high preference of cesium uptake despite low cation exchange capacity (CEC). This characteristic induces selective adsorption of cesium against competitive cations. From previous spectroscopic investigations including 133Cs Magic Angle Spin Nuclear Magnetic Resonance (MAS-NMR), broad and narrow peaks which indicates outer-sphere and inner-sphere complex each. From width of two split peaks, however, uptake ratio of cesium becomes lower when competitive alkali cations coexist in certain ratio. These results show that population and physicochemical properties of competitive cations would affect the preference of adsorption in water solution. In this study, Molecular Dynamic (MD) simulation were performed to study features and preference of cesium adsorption against the other alkali cation (Li, Na, K, Rb) on illite surface using LAMMPS package and CLAYFF. The simulation shows that the cesium uptake becomes more selective if the ratio of cesium is more than 0.8 and splits in series of Li, Rb, Na, K under 0.5. Features of cation population also presents that potassium ion disturbs adsorption of cesium. From these results, hydration state of cation, structure and charge balance would be key effects in adsorption system.
E-mail wh8426@knu.ac.kr