Study on the effect of lanthanum-modified bentonite and vallisneria spiralis combination on cobalt at the sediment-water interface
In order to explore the removal effects and mechanisms of dissolved cobalt(Co)in shallow lake sediments by the combination of vallisneria spiralis(V.spirals)and lanthanum-modified bentonite(LMB).The eutrophic sediment of Meiliang Bay in the Taihu Lake is the research object.Indoor simulation experiments(control group,LMB group,V spiralis group,and LMB & V.spiralis group)were conducted based on High-resolution Peeper(HR-Peeper)to analyze the in-situ and vertical distribution characteristics of dissolved Co,Fe(Ⅱ)and Mn in the interstitial water from 10 to-100mm of the sediment profile on days 15,35 and 66after the addition of remediation materials.The results indicated that LMB and V spiralis can significantly improve the redox environment of sediment profiles(P＜0.05).Compared with the control group,the average concentration of dissolved Co decreased by 0.59％～38.18％in experimental groups.The release and migration of Co during combined use were mainly affected through adsorption of iron/manganese plaque on the root surface and complexed adsorption by LMB.In addition,LMB can promote the growth of V spiralis.At 0～2cm sediment,the proportion of mobile Co(F1+F2+F3)was 54.91％～80.49％.The combination promoted the transformation of acid extractable state to reducible and oxidizable state.The release of Co at the SWI is mainly controlled by the oxidation-reduction of manganese.
vallisneria spiralislanthanum-modified bentonitesedimentdissolved Co
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