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.
Two BC（black carbon） samples, BC700 and BC400, were prepared from China fir wood by pyro- lytic 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 BCT00 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 influ- ence to TBT forms in the solution. It was found that TBT existed in both cationic （TBT＋ ） and uncharged spe- cies at pH=4. 00 and 6.25 but mostly in uncharged species（TBT） at pH=8.00. TBT sorption reached maxi- mum 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 BCT00 was mainly physical adsorption and electrostatic interaction while hydrophobic partitioning also significantly contributed to TBT sorption on BC400.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第1期84-90,共7页
Chemical Journal of Chinese Universities
基金
国家“九七三”计划项目(批准号:2009CB421603)
国家自然科学基金(批准号:40771183)资助
关键词
黑碳
三丁基锡
吸附机理
盐度
PH
Black carbon
Tributyltin
Sorption mechanism
Salinity
pH
