金属离子对长期污染土壤中多环芳烃解吸的影响

研究了离子强度、不同金属离子对土壤中PAHs表观解吸水平的影响.根据Pearson原理计算了菲、荧蒽、芘和苯并k]荧蒽等几种PAHs的碱性特征参数并据此分析了其酸碱性类型.结果表明:实验条件下,解吸液中离子强度并非影响土壤中PAHs解吸的控制要素;不同硬度酸性金属离子与PAHs之间的酸碱作用是影响土壤中PAHs解吸水平变化的关键.硬酸性金属离子Ba2+、Al3+、Ca2+对土壤中PAHs的解吸具有促进作用,软酸性离子Hg2+、Ag+则具有抑制作用,比较而言交界酸性金属离子Cu2+、Fe2+、Zn2+在提高土壤中PAHs解吸上作用更加明显.

Effects of metallic cations on desorption of polycyclic aromatic hydrocarbons from long-term contaminated soil

Effects of ion strength and ion types on desorption of polycyclic aromatic hydrocarbons (PAHs) were examined. Based on Pearson principle, the basic characteristics of phenanthrene (PHE), fluoranthene (FLU), pyrene (PYR) and benzo fluoranthene (B Fl) were calculated to determine their acidic-basic types. The experimental results indicated that ion strength was not the key controlling factor on PAHs desorption. The acidic-basic interaction between metallic ions with different hardness and PAHs was the key influencing point on the PAHs desorption level variation from the contaminated soil. Hard acidic metallic cations, such as Ba²⁺, Al³⁺ and Ca²⁺, can expedite PAHs desorption. In contrast, acidic cations, such as Hg²⁺ and Ag⁺, played an inhibition role. The borderline acidic cations, such as Cu²⁺, Fe²⁺ and Zn²⁺, can enhance PAHs desorption more significantly.