焦化厂土壤中多环芳烃分布特征及淋洗粒级分割点确定  

Distribution Patterns of PAHs in Soils from Coking Plant and the Particle-Size Cut Points of Soil Washing

作　　者：李合莲[1,2] 陈家军[1] 吴威[1] 朴雪松[1] 姜琳[3] 史震天[1] 孙添伟[1] 

机构地区：[1]北京师范大学环境学院,水环境模拟国家重点实验室,北京100875 [2]济南大学资源与环境学院,济南250022 [3]北京市环境保护科学研究院,北京100037

出　　处：《环境科学》2011年第4期1154-1158,共5页Environmental Science

基　　金：北京市科委项目(SF2008-02);中央高校基本科研业务费专项(2009SD-19);济南大学科研基金项目(XKY0931)

摘　　要：土壤粒径分布和污染物在不同粒级土壤中的分布特征是污染土壤淋洗可处理性的重要依据,淋洗粒级分割点则是淋洗工艺的重要参数.根据土壤异位淋洗的技术要求,在焦化厂污染场地进行了采样,测定了土样的粒径分布曲线及不同粒级土壤中美国EPA优控的16种多环芳烃(PAHs)的初始浓度,并采用Tween 80和Triton X-100溶液对不同粒级污染土样进行了振荡清洗实验.结果表明,16种PAHs在6个粒级中的总浓度在6.27～40.18 mg/kg范围,呈双峰分布模式,单个PAH污染物的最高浓度大多出现在250～500μm的颗粒中,50～75μm的颗粒中污染物浓度最低;PAHs去除率与其初始浓度及土壤特性有关,初始浓度越低,去除率越高,粗颗粒中由于有机碳含量较高,PAHs去除效率反而低于细颗粒.根据清洗效果并从废物减量化角度出发,确定以50μm作为土壤淋洗的粒级分割点,这样减容率可以达到82.95%.Soil particle size distribution and contaminants distribution patterns in different soil size fractions are the basis of soil treatability using soil washing method.Soil particle-size cut points are important parameters of soil washing process.According to ex situ soil washing technology,soil samples were collected in a former coking plant.The soil particle size distribution and the concentrations of 16 polycyclic aromatic hydrocarbons（PAHs） in USEPA priority list were analyzed.Tween 80 and Triton X-100 solutions were used to clean the polluted soil with different particle size.Results showed that the total concentrations of 16 PAHs ranged from 6.27 to 40.18 mg /kg dry weight in the six soil size fractions and present a bimodal distribution.The maximum individual PAH concentration mostly occurred in the 250-500 μm size fraction.The lowest individual PAH concentration was in the 50-75 μm size fraction.The removal efficiencies of PAHs in different soil size fractions depended on their initial concentrations and the characteristics of soil.The PAHs removal efficiencies in coarser size fractions were lower than that in the finer size fractions owing to their higher organic carbon content.Based on the removal efficiency of PAHs in each soil size fractions by surfactant solution and the requirements of waste volume reduction,50 μm was determined as the particle-size cut point.Then,82.95% volume reduction can be achieved.

关 键 词：焦化厂 多环芳烃 分布特征 土壤淋洗 粒级分割点 

分 类 号：X131[环境科学与工程—环境科学] X53