Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6581299 | Chemical Engineering Journal | 2016 | 8 Pages |
Abstract
Strontium ion (Sr2+) separation from seawater has attracted attention for radioactive pollutants removal and for Sr2+ recovery. Herein, we synthesized titanate nanotubes (TiNTs) via a simple hydrothermal reaction, characterized their physicochemical properties, and systematically evaluated Sr2+ sorption behavior under various reaction conditions corresponding to seawater environments. The synthesized TiNTs exhibited a fibril-type nanotube structure with a high specific surface area (260Â m2/g). Sr2+ adsorption on TiNTs rapidly occurred following a pseudo-second-order kinetic model and was in good agreement with the Langmuir isotherm model, indicating a maximum adsorption capacity of 97Â mg/g. Based on the Sr2+ uptake and Na+ release with a stoichiometric balance, the Sr2+ sorption mechanism on TiNTs was ion exchange between Na+ in the TiNT lattice and Sr2+ in the solution phase, as confirmed by XRD and Raman analysis. Among the competitive ions, Ca2+ significantly hindered Sr2+ sorption on TiNTs, whereas Na+ only slightly affected Sr2+ sorption, despite the Na+ exchange sorption mechanism. The effect of Ca2+ on Sr2+ sorption was evaluated by introducing a distribution coefficient (Kd) as a critical factor in determining the selectivity, which revealed a slightly higher selectivity for Sr2+. The Sr2+ adsorption-desorption test in a real seawater medium enabled the determination of Kd and the concentration factor (CF) for co-existing matrix ions in seawater; these values were evaluated for Sr2+ removal and recovery from seawater. TiNTs were regenerated by acid treatment and reused through consecutive adsorption-desorption experiments. While most studies addressing Sr2+ sorption using TiNTs aimed for extraction from wastewater and radioactive wastewater, this study elucidated Sr2+ sorption behavior under seawater conditions and provided insights into developing the removal and recovery processes from seawater.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Jungho Ryu, Soonhyun Kim, Hye-Jin Hong, Jeongsik Hong, Minsun Kim, Taegong Ryu, In-Su Park, Kang-Sup Chung, Jum Suk Jang, Byoung-Gyu Kim,