Preparation and ion exchange properties of egg-shell glass beads with different surface morphologies

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• 作者：Chun Shen ; Yujun Wang ^{wangyujun@mail.tsinghua.edu.cn} ; Jianhong Xu ; Yangcheng Lu ; Guangsheng Luo ; ^{gsluo@mail.tsinghua.edu.cn}
• 关键词：Porous glass ; Subcritical water treatment ; Heavy metal adsorption ; Egg-shell structure
• 刊名：Particuology
• 出版年：2012
• 期刊代码：P32_16742001
• 类别：ce
• 出版时间：June, 2012
• 卷：10
• 期：3
• 页码：317-326
• 文件大小：1598 K

摘要

A subcritical water treatment method was developed for preparing porous-surfaced glass beads with an egg-shell structure in a batch reactor. Based on the 鈥渃orrosion-ion-migration-recondensation鈥?strategy, ordinary soda-lime glass beads with a diameter of about 100 渭m were made first to react with subcritical water to effect controlled quantity of silicate dissolution of glass by adjusting treatment time and temperature. The dissolved silicate was then made to recondense on the glass core to form different porous shell morphologies: pores, flakes and fibers. Among these, glass beads coated with fibers with surface area of 154.5 m²/g, pore volume of 0.27 cm³/g and pore size of 7.1 nm were obtained at 573 K after 2 h of treatment. The prepared porous-surfaced glass beads were then used as adsorbent for heavy metal ions, showing various ion exchange properties. Glass beads covered with fibers displayed fast kinetics and high sorption capacity because of their egg-shell structure and high surface area. More than 90%of copper ions were adsorbed within 100 min from a solution with an initial concentration of 110 mg/L at 313 K. Ion sorption capacities were 149.33, 81.33 and 42.96 mg/g respectively for Ag⁺, Cu²⁺ and Ni²⁺ at 313 K. A green and low-cost method was thus developed to produce egg-shell-structured porous glass with high sorption capacity.