An experimental study about the effects of phosphorus loading in river sediment on the transport of lead and cadmium at sediment-water interface
An experimental study about the effects of phosphorus loading in river sediment on the transport of lead and cadmium at sediment-water interface
复制标题
河流沉积物磷负荷对沉积物-水界面铅、镉迁移影响的实验研究
DOI：
10.1016/j.scitotenv.2020.137535
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发表时间：
2020
影响因子：
9.8
通讯作者：
Hu Hongwei
中科院分区：
文献类型：
--
作者：
Shen Tingting;Tang Yuanyuan;Li Yong Jie;Liu Yunsong;Hu Hongwei
河流沉积物中的磷对水体富营养化环境中重金属在沉积物-水界面的迁移转化起着重要作用。为阐明磷负荷的影响，以不同磷含量的沉积物为研究对象，研究了沉积物对Pb 2+和Cd 2+的吸附/解吸以及吸附/解吸过程中磷的释放行为。结果表明，Pb ~（2+）离子与沉积物中的磷离子之间具有较强的亲合力，Pb ~（2+）离子与沉积物中的磷离子之间具有较强的亲合力。在单金属体系中，所有类型沉积物对Pb 2+的吸附容量（15.04-19.44 mg g−1）均高于对Cd 2+的吸附容量（4.68-5.56 mg g−1）。而在二元金属体系中，共存的Cd ~（2+）对Pb ~（2+）的吸附影响不大，但使Cd ~（2+）的吸附量降低5倍以上。沉积物中磷含量的增加，可提高沉积物对Pb 2+的吸附量和截留能力。同时，沉积物中的Pb ~（2+）对磷的释放也有明显的抑制作用。Pb和Pb + Cd负载的沉积物在解吸过程中的磷释放量比未吸附重金属的沉积物低50倍以上，而单一Cd负载的沉积物的磷释放量降低了2倍。此外，X射线光电子能谱的结果表明，在沉积物和上覆水的铅迁移的P负载的关键作用。研究结果对重金属和磷在沉积物-水界面的迁移具有重要意义，为进一步阐明水体富营养化环境中重金属和磷的二次污染机理提供了新的思路。
Phosphorus (P) in the river sediment plays an important role in the fate and transport of heavy metals at sediment-water interface of the aquatic eutrophication environment. To explicate the effect of P loading, the sediments with different P contents were employed in this study to experimentally investigate the adsorption/desorption of Pb2+and Cd2+and the releasing behavior of P during the adsorption/desorption processes. Results illustrated a strong affinity between Pb2+ions and the P-containing sediments in both single Pb and binary Pb + Cd systems. In single-metal systems, the Pb2+adsorption capacities of all types of sediments (15.04–19.44 mg g−1) were higher than those for Cd2+(4.68–5.56 mg g−1). While in binary-metal systems, the Pb2+adsorption was slightly influenced by the coexisting Cd2+, but the Cd2+adsorption capacities were decreased by over 5 times. Moreover, the adsorption amount and retention ability of Pb2+on sediment were enhanced by increasing content of P in the sediment. Meanwhile, the releasing of P was also closely depended and significantly inhibited by the Pb2+attached on the sediment. The P release amounts during the desorption processes of Pb- and Pb + Cd-loaded sediments were over 50 times lower than those from the raw sediments (sediments without heavy metals adsorbed), but the values decreased by a factor of two for the single Cd-loaded sediments. Furthermore, the results of X-ray photoelectron spectroscopy indicated the crucial role of P loading in Pb transport in the sediment and overlaying water. The findings in this study showed important implications for the transport of heavy metals and P at the sediment-water interface and offered new insights for further explicating the mechanisms of secondary pollution caused by heavy metals and P in aquatic eutrophication environment.