菲在四种碳纳米管上的解吸行为研究

Desorption of phenanthrene sorbed on multi-walled carbon nanotubes

碳纳米材料是当前环境领域关注的热点之一.本研究以菲为模型污染物,以Tenax TA树脂为助解吸剂,研究了菲在4种碳纳米管上的非生物解吸动力学以及碳纳米管理化性质对菲解吸的影响机理.结果表明,当老化60d,碳纳米管上菲初始吸附量为578mg·kg-1时,解吸30d后菲累积解吸量随时间变化不明显,解吸35d后碳纳米管上菲的解吸率为14.28%～50.71%,因此菲在碳纳米管上存在不可逆迟滞解吸效应.菲在碳纳米管上的解吸符合三相一级解吸动力模型,包括快解吸、慢解吸以及极慢解吸三部分,其中快解吸部分所占比例较小(1%～3%),慢解吸部分(16%～54%)和极慢解吸部分(43%～83%)所占比例相对较大,4种碳纳米管上菲累积解吸量与慢解吸部分呈显著正相关(p<0.01);菲累积解吸量与碳纳米管比表面积和中孔孔容呈显著负相关(p<0.05),与碳纳米管粒径呈显著正相关(p<0.05).本研究表明比表面积较大的碳纳米管能显著降低环境中有机污染物的生物有效性.

Carbonaceous materials have attracted more and more attention around the world.In this study,the Tenax TA-aided desorption of phenanthrene from four multi-walled carbon nanotubes （MWCNTs） was studied.Phenanthrene was spiked onto four pure MWCNTs with the initial concentration of 578 mg·kg-1,and subsequently aged for 60 d.After desorption for 30 d,desorption amounts of phenanthrene from pure MWCNTs did not change remarkably.After desorption for 35 d,the desorption ratios were 14.28%～50.71%,indicating that there existed an irreversible hysteresis for desorption of phenanthrene from MWCNTs.The desorption of phenanthrene was in line with the three-phase first-order kinetic model,which consisted of rapid,slow,and very slow desorption fractions.The rapid fraction （1%～3%） was much less than the slow （16%～54%） and very slow （43%～83%） desorption fractions.The desorption amounts were positively correlated with the slow desorption fractions （p0.01） for the four MWCNTs.The properties of MWCNTs,such as specific surface area,mesopore volume and pore size,had great influences on the desorption of phenanthrene （p0.05）.This study indicated that carbon nanotubes with large specific surface area can decrease the bioavailability of hydrophobic organic pollutants in environment.