锁磷剂和增氧剂对沉积物内源污染物钴的吸附

Adsorption of endogenous pollutant Co in sediments,by phosphorus-locking agent and oxygen-enhancing agent

为探究不同吸附材料(锁磷剂和增氧剂)对沉积物内源污染物Co的影响机制,以太湖梅梁湾为研究区域,设计3组室内模拟试验(对照组、增氧剂组及锁磷剂组),基于高分辨率平衡式间隙水采样(HR-Peeper)装置采集4个阶段(加入吸附材料后的第4天、30天、90天、150天)水样,解析原位覆盖条件下沉积物剖面溶解态Co、Fe(Ⅱ)、Mn的垂向分布特征及相互作用机制。结果表明:锁磷剂和增氧剂未造成水体中的pH值和Eh值的剧烈变化;沉积物剖面中溶解态Co质量浓度降低了1.29%~45.87%,且30 d时的吸附效果最好;增氧剂组及锁磷剂组沉积物-水界面Co释放通量较对照组分别降低了1.00μg/(m^(2)·d)和1.19μg/(m^(2)·d);沉积物剖面Co的释放受铁、锰的氧化还原控制,且主要受锰的氧化还原控制;增氧剂对钴的吸附效果优于锁磷剂,且有效吸附时间更久。

In order to explore the influence mechanism of different adsorbents(phosphorus-locking agent and oxygen-enhancing agent)on the endogenous pollutant Co in sediments,the Meiliang Bay of Taihu Lake was selected as the study area.Three groups of indoor simulation experiments,including the control group,oxygen-enhancing group and phosphorus-locking group,were designed in this study.Water samples were collected in four stages(the 4th,30th,90th and 150th day after the addition of adsorbents)based on the high-resolution pore water sampling device(HR peeper).The vertical distribution characteristics and interaction mechanism of dissolved Co,Fe(Ⅱ)and Mn in sediment profile under the in-situ coverage were explored.The results show that phosphorus-locking agent and oxygen-enhancing agent did not cause drastic changes in Eh and pH in the water body.The dissolved Co concentration in the sediment profile decreased by 1.29%-45.87%while the adsorption effect was the best at 30th day.Comparing with the control group,the release flux of Co at the sediment-water interface of oxygen-enhancing group and phosphorus-locking group decreased by 1.00μg/(m^(2)·d)and 1.19μg/(m^(2)·d),respectively.The release of Co in the sediment profile was controlled by the redox of Fe and Mn,and mainly by the redox of Mn.In addition,the adsorption effect of oxygen-enhancing agent on Co was better than that of phosphorus-locking agent,and the reaction time was also longer.