腐殖质对BDE209、Pb和Cd在水/沉积物界面吸附行为的影响

水/沉积物界面是有机和无机污染物的物理、化学等过程的重要载体和场所。为了探究溴代阻燃剂与重金属在水/沉积物体系的分布规律,以电子垃圾拆解地水体中常见的溴代阻燃剂十溴联苯醚(BDE209)和重金属Pb、Cd为目标污染物,考察了腐殖质对BDE209、Pb和Cd在水/沉积物界面吸附行为的影响。红外光谱分析表明沉积物腐殖质活性基团包括醇、酚和羧基类等官能团;1H核磁共振分析显示沉积物腐殖质主要由碳水化合物与脂肪族类化合物组成。吸附试验结果表明,水体中腐殖质能够促进沉积物表面BDE209、Pb和Cd的释放,BDE209在水/沉积物体系的吸附行为主要受水溶性腐殖质的影响,而对Pb、Cd而言,负载于沉积物表面的碱溶性腐殖质比水溶性腐殖质对其分配行为的作用更显著。此外,沉积物组分对BDE209在水/沉积物体系的分配行为无显著影响;粘土组分对Pb、Cd的富集能力高于砂粒,并且对Pb的富集能力比Cd更为突出。

Effect of Humus on the Adsorption Behavior of Decabromodiphenyl Ether (BDE209), Pb and Cd at the Water/Sediment Interface

Water/sediment interface is an important environmental boundary for organic and inorganic pollutants to conduct physical and chemical reactions. In order to explore the distribution of brominated flame retardants and heavy metals at water/sediment interface, decabromodiphenyl ether (BDE209), Pb and Cd, which are ubiquitous contaminants in e-waste dismantling area, were chosen as the representative pollutants and the effect of humus on the adsorption behavior of BDE209, Pb and Cd at water/sediment interface has been investigated. The result of infrared spectral analysis showed that the active groups of humus in sediment included functional groups such as alcohol, phenol and carboxyl. 1H NMR analysis demonstrated that humus mainly consisted of carbohydrate and aliphatic compounds. The adsorption results revealed that humus could promote the release of BDE209, Pb and Cd from sediment to aqueous phase. Moreover, the effect of water-soluble humus on the adsorption behavior of BDE209 in water/sediment system was more significant compared with that of alkali-soluble humus. However, alkali-soluble humus adhered on the surface of sediment had a greater influence on the distribution of Pb and Cd at water/sediment interface than water-soluble one. Furthermore, the components of sediment had no significant influence on the distribution of BDE209 in water/sediment system. Clay had stronger adsorption capacity than sand for Pb and Cd, and the action was more significant for Pb.