Choi Hyeok, Al-Abed Souhail R
National Risk Management Research Laboratory, US Environmental Protection Agency, Cincinnati, OH 45268, USA.
J Hazard Mater. 2009 Jun 15;165(1-3):860-6. doi: 10.1016/j.jhazmat.2008.10.100. Epub 2008 Nov 5.
Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K(F) (Lkg(-1)) spanned several orders of magnitude, ranging from logK(F) of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.
多氯联苯（PCBs）在沉积物上的吸附是决定其在水生环境中迁移性、生物可利用性和化学分解的关键过程。为了检验目前用于解释PCBs吸附的方法的有效性，将2-氯联苯在沉积物中对碳质成分（活性炭、炭黑、煤、烟灰、石墨、粉煤灰、木材）的吸附的比较结果，与碳质成分的结构、形态、晶体学和组成特性进行了宏观关联。由于弗伦德利希吸附常数K(F)（Lkg(-1)）跨越了几个数量级，从活性炭的logK(F)为6.13 - 5.27、炭黑为5.04、煤为3.83到木材为3.08，考虑到沉积物中有机碳的各种形式、性质和来源，有机碳分配方法应更具体地分类。从具有快速和慢速吸附分数的经验动力学模型中数值定义的吸附速率常数和分数参数，与碳质成分的物理化学性质密切相关。具有特定性质和观点的吸附解释方法，如有机碳分配、烟灰碳分布或表面积相关性，不能很好地解释吸附容量、快速和慢速吸附动力学以及分配系数的总体结果。强调沉积物的非均质性以及涵盖其碳质成分之间分配的困难也很重要。
