腐植酸和黑炭的提取及其对菲和芘的吸附行为

从河水沉积物中提取腐植酸和黑炭，通过元素分析仪、总有机碳仪、扫描电子显微镜和Zeta电位仪对其进行表征分析。研究了多环芳烃（PAHs）的代表物质菲和芘分别在腐植酸和黑炭上的分配行为并测定其分配系数，以及Ca2+浓度对菲、芘吸附的影响。结果表明:河水沉积物中提取的腐植酸和黑炭的主要元素组成是碳和氧，两者含有较多的芳香烃组分；水生植物是腐植酸和黑炭来源的主要贡献者；腐植酸呈发泡絮状结构，黑炭具有微孔结构；黑炭颗粒表面带有的负电荷明显少于腐植酸，其分子间的斥力作用较小。基于以上结果，认为黑炭的吸附能力高于腐植酸。菲和芘在腐植酸上分配系数的对数值（lg K_d）分别为3.55和4.55，在黑炭上分配系数的对数值（lg K_d）分别为4.57和5.35，这说明单位质量腐植酸和黑炭上芘的吸取量高于菲；菲和芘在腐植酸和黑炭上的吸附量随着Ca2+浓度的增加而呈先增加后减少的趋势。

EXTRACTION OF HUMIC ACID AND BLACK CARBON AND THEIR ADSORPTION BEHAVIORS FOR PHENANTHRENE AND PYRENE

In this study, humic acid and black carbon were firstly extracted from river sediments, then characterized and analyzed by element analyzer, total organic carbon meter, scanning electron microscope and Zeta potential meter. The distribution behaviors of phenanthrene and pyrene, representative substances of polycyclic aromatic hydrocarbons (PAHs) on humic acid and black carbon were studied, and their distribution coefficients were determined, as well as the influence of Ca2+ concentration on the adsorption of phenanthrene and pyrene were investigated. The results showed that the main elemental composition of humic acid and black carbon extracted from river sediments were carbon and oxygen, both of which contained relatively rich aromatic hydrocarbon components; aquatic plants were the main contributors of the source of humic acid and black carbon; humic acid had a foamed floc structure, and black carbon had a microporous structure; the negative charge on the surface of black carbon particles was relatively less than that of humic acid, so the repulsive force between the black carbon and pollutants was weaker. The above characterization results correspondingly provided theoretical basis for the adsorption capacity of black carbon higher than that of humic acid. The logarithmic value (lg K_d) of the partition coefficient of phenanthrene and pyrene on humic acid were 3.55 and 4.55, respectively, and that on black carbon were 4.57 and 5.35, respectively, which showed that the absorption amount of pyrene on unit mass of humic acid or black carbon was higher than that of phenanthrene; the adsorption amount of phenanthrene and pyrene on the humic acid and black carbon also showed a trend of increasing and then decreasing with the increase of Ca2+ concentration.