摘要
选用石英砂填充柱模拟土壤体系,通过对比在有无膨润土颗粒(Bentonite particles)存在时得到的多壁碳纳米管(MWCNTs)的穿透曲线和滞留曲线,考察膨润土颗粒对MWCNTs在多孔介质中迁移沉积行为的影响.实验选取的Na Cl溶液离子强度为1 mmol·L-1和30 mmol·L-1,Ca Cl2溶液离子强度为0.3 mmol·L-1和1.2 mmol·L-1.溶液p H不进行调节,p H值大约为5.6.研究结果表明,在低离子强度Na Cl(1 mmol·L-1)溶液中,有膨润土颗粒共存时MWCNTs的穿透曲线和滞留曲线与没有膨润土颗粒共存时相近,表明该条件下MWCNTs的迁移和沉积行为不受膨润土颗粒影响,而在高离子强度Na Cl(30 mmol·L-1)溶液中,有膨润土颗粒共存时MWCNTs的穿透曲线低于没有膨润土颗粒共存时MWCNTs的穿透曲线,表明该条件下膨润土颗粒会抑制MWCNTs的迁移,且增加的滞留主要发生在柱子入口端;在Ca Cl2溶液中,无论离子强度的高低(0.3 mmol·L-1和1.2 mmol·L-1),有膨润土颗粒共存时,MWCNTs的穿透曲线和滞留曲线都不发生变化,说明在二价溶液中膨润土颗粒对MWCNTs的迁移和沉积行为影响不大.
The influences and mechanisms of bentonite particles on the transport and deposition kinetics of multi-walled carbon nanotubes （ MWCNTs ） in irregular quartz sand were examined by direct comparison of both breakthrough curves and retained profiles with bentonite particles （10 mg·L^-1 ） in MWCNTs suspension versus those without bentonite particles. Packed column experiments were conducted in both NaCl （1 mmol·L^-1 and 30 mmol·L^-1 ionic strengths） and CaCl2 （0.3 mmol·L^-1 and 1. 2 mmol·L^-1 ionic strengths） solutions at unadjusted pH （-5. 6）. The breakthrough curves and retained profiles of MWCNTs with and without bentonite particles were almost the same in 1 mmol·L^-1 NaCl solutions, indicating that bentonite particles in solutions had no obvious influence on MWCNTs transport and deposition at low ionic strength NaCl solutions. However, the breakthrough curve of MWCNTs with bentonite particles in solutions was lower than that without bentonite particles in 30 mmol·L^-1 NaCl solutions, demonstrating that bentonite particles decreased MWCNTs transport at high ionic strength in NaCl solutions, and the increased MWCNTs deposition with bentonite particles was mainly observed at segments near to column inlet. In contrast to the opposite observation for MWCNTs transport with bentonite particles at low and high ionic strengths NaCl solutions, breakthrough curves and retained profiles of MWCNTs with bentonite particles and without bentonite particles were similar at both low and high ionic strengths CaCl2 solutions, demonstrating that bentonite particles had no influence on the transport and deposition of MWCNTs in CaCl2 solutions.
出处
《环境化学》
CAS
CSCD
北大核心
2015年第4期671-677,共7页
Environmental Chemistry
基金
国家自然科学基金项目(21377006
40971181)资助
