3种多环芳烃在木炭上的吸附/解吸行为  

Sorption and Desorption Behaviors of Three PAHs by Charcoals

作　　者：周尊隆[1] 吴文玲[1] 李阳[1] 孙红文[1] 

机构地区：[1]南开大学环境科学与工程学院,天津市城市生态环境修复与污染防治重点实验室,天津300071

出　　处：《农业环境科学学报》2008年第2期813-819,共7页Journal of Agro-Environment Science

基　　金：国家自然科学基金重点项目(20737002)

摘　　要：通过控制氧化时间自制了3种结构不同的木炭(charcoal),对其性质进行了表征,并研究了3种典型多环芳烃菲、蒽、芘在木炭上的吸附/解吸行为。结果表明,通过控制加热处理时间,可以制得结构和性质不同的木炭。多环芳烃在木炭上的吸附/解吸均呈现明显的非线性,可用Freundlich模型描述。吸附系数(Koc)在105.7-106.6之间,而吸附的线性因子(n)在0.4-0.7之间。分配作用和表面吸附共同控制着多环芳烃在木炭样品中的吸附,因此,Koc及n与木炭的结构、多环芳烃的疏水性及分子大小有关。多环芳烃在木炭上的解吸出现不同程度的滞后现象,解吸滞后程度与多环芳烃分子大小有关,表现为芘的解吸滞后程度大于其余两种三环芳烃;芳香碳及极性都会影响解吸滞后程度,而吸附剂的比表面积和致密脂肪碳是关键的结构因素。Three structurally different charcoals were developed by controlling oxidation time, whose structures were characterized. Sorption and desorption of three representative polycyclic aromatic hydrocarbons （PAHs）, phenanthrene （PHE）, anthracene （ANT） and pyrene （PYR）, on these charcoals were studied. The results showed that the three charcoals were quite different in chemical composition and structure through changing the oxidation time, though they were generated from the same material. All the sorption and desorption isotherms of PAHs on the charcoals were nonlinear, which can be well fitted by Freundlich model, and the nonlinearity had a positive correlation with O/C ratio of the charcoals. Koc and n values ranged 10^5.7～10^6.6 and 0,4～0.7, respectively, mainly dependent on charcoal structure, the hydrophobicity and molecular volume of PAHs, Adsorption was the main mechanism for the sorption of PAHs on these charcoals, whereas partition can not be neglected on charcoal samples with short oxidation time, Desorption hysteresis of the PAHs on charcoals was evident, The larger the PAHs molecule, the more hysteretic their desorption, and hence, desorption hysteresis of pyrene was more evident than the other two PAHs. Besides, desorption hysteresis also related to the aromaticity and polarity of charcoals, and among which the existence of rigid aliphatic carbon and surface area were the two key factors.

关 键 词：木炭 多环芳烃 吸附 非线性 解吸滞后 

分 类 号：X592[环境科学与工程—环境工程]