高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (1): 84.doi: 10.7503/cjcu20120288

• 分析化学 • 上一篇    下一篇

海水体系中黑碳吸附三丁基锡的行为与机理

肖小雨1, 盛光遥2, 邱宇平2   

  1. 1. 浙江工业大学生物与环境工程学院, 杭州 310032;
    2. 同济大学环境科学与工程学院, 污染控制与资源化研究国家重点实验室, 上海 200092
  • 收稿日期:2012-03-29 发布日期:2012-12-31
  • 通讯作者: 邱宇平,男,博士,教授,主要从事环境污染化学方向研究.E-mail:qiu_yuping@yahoo.com.cn E-mail:qiu_yuping@yahoo.com.cn
  • 基金资助:

    国家"九七三"计划项目(批准号: 2009CB421603)和国家自然科学基金(批准号: 40771183)资助.

Sorption Mechanism of Tributyltin to Black Carbon in Seawater System

XIAO Xiao-Yu1, QIU Yu-Ping2   

  1. 1. College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China;
    2. State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
  • Received:2012-03-29 Published:2012-12-31

摘要:

在700, 400℃条件下热解碳化杉木制得2种黑碳(BC700和BC400). 研究了海水体系中, pH和盐度影响下2种黑碳(BC)对三丁基锡(TBT)的吸附行为与机理. 实验结果表明, BC700的比表面积较大, BC400的有机质含量较高. 盐度的增加(5~35 g/kg)使BC表面净电荷降低, 静电作用减弱; 但同时导致盐析效应增强, 使TBT的有效浓度增大, 综合结果导致2种BC对TBT的吸附增加了1.03~2.12倍. 当溶液pH为 4.00和 6.25时, TBT以离子(TBT+)和中性(TBT)形态共同存在, 而在pH 为8.00时几乎全为中性态, 分子形态的不同导致TBT与BC间的作用机理发生变化. TBT的最大吸附发生在pH=6.25时, 这是静电作用、 物理吸附和疏水分配等多种机制共同作用的结果. X射线光电子能谱(XPS)分析结果表明, Sn3d5/2峰结合能随着pH的降低而增加, 证明TBT与BC之间存在静电作用. 因此可以认为, TBT在BC700上的吸附主要为物理吸附和静电作用, 而在BC400上的吸附则由疏水分配、 物理吸附和静电吸引共同主导.

关键词: 黑碳, 三丁基锡, 吸附机理, 盐度, pH

Abstract:

Two BC(black carbon) samples, BC700 and BC400, were prepared from China fir wood by pyrolytic charring at 700 and 400℃, respectively. The sorption behavior and mechanisms of tributyltin(TBT) on the two BC samples were evaluated as a function of seawater pH and salinity. The results indicated that BC700 had a higher specific surface area but lower content of organic matter than BC400. TBT sorption on BC700 was primarily a physical adsorption process while hydrophobic partitioning also significantly contributed to TBT sorption on BC400. Increasing salinity from 5 to 35 g/kg facilitated TBT sorption by 1.03-2.12 times as an overall result of the enhancing effective concentration of TBT because of 'salting-out’ and the reducing role of electrostatic interaction because of BC surface charge neutralization. Environmental pH had a significant influence to TBT forms in the solution. It was found that TBT existed in both cationic(TBT+) and uncharged species at pH=4.00 and 6.25 but mostly in uncharged species(TBT) at pH=8.00. TBT sorption reached maximum at pH=6.25, as compared to pH=4.00 and 8.00, due presumably to multiple mechanisms involving electrostatic interaction, physical adsorption and hydrophobic partitioning between TBT and BC. In addition, XPS spectra showed that the binding energy of Sn3d5/2 peak shifted higher with decreasing pH, confirming the TBT-BC electrostatic interaction. Therefore, sorption of TBT on the BC700 was mainly physical adsorption and electrostatic interaction while hydrophobic partitioning also significantly contributed to TBT sorption on BC400.

Key words: Black carbon, Tributyltin, Sorption mechanism, Salinity, pH

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