Effects Of Humic Substances On Adsorption And Fraction Distribution Of Heavy Metals In Sediments From Lake Wuliangsuhai

Organic matter is an important carrier of the environment, it has important implications to transformation and phase distribution of elements. As different components of humus, fulvic acid, humic acid and humin have different composition and structure, which lead to different adsorption behavior and fraction distribution of heavy metals in sediment. This paper based on the separation extraction and purification of humus different components from natural lake sediment, and take Wuliangsuhai lake original sediment and removal of organic matter sediment as adsorbents to research the reaction mechanism of heavy metals adsorption behavior and fraction distribution in sediment, which is better to illustrate differences of interaction mechanism between heavy metals and humus components in lake ecological environment, it is also important to understand the environmental effect of humus. This paper achieved the following main conclusions.(1) The results shows that with the increasing of the additive amount, inhibitory effect of humus (FA, HA and HM) on heavy metals (Cu, Pb, Zn and Cd) in original sediments gradually increased; Effect of FA and HA on Cu, Pb, Zn and Cd in the removal of organic matter sediments is similar to the original sediments, and effect of HM on Cu, Pb, Zn and Cd in the removal of organic matter sediments is also similar to the original sediments, but HM has an promote effect on Cu in the removal of organic matter sediments. Experiment derives the inhibitory sequence is HA> FA> HM.(2) The inhibition effect of FA-Myri. Area on Cu and Cd is the weakest, and the inhibition effect of FA-Phra. Area on Pb and Zn is the weakest. The inhibition effect of HA-Phra. Area on Cu, Zn and Cd is the weakest, and the inhibition effect of HA-Pota. Area on Pb is the weakest; The inhibition effect of HM-Myri. Area on Cu and Cd is the weakest, and the inhibition effect of HM-Phra. Area on Pb and Zn is the weakest.(3) whether remove the organic matter or not, with the amount of FA, HA and HM increasing, in each ecological function areas, the content of the carbonated fractions are decreasing, organic matter fractions are increasing.(4) Studies shows that FA, HA and HM have significant different influence on the fraction redistribution of heavy metals. In contrast, the effect of FA on exchangeable Cu is stronger than HA and HM, the effect of HM on exchangeable Pb, Zn and Cd is stronger than FA and HA. HA has strongest inhibition effect on carbonate Cu and Pb, and HM has strongest inhibition effect on carbonate Cd. FA, HA and HM hve a greater impact on organic matter fraction of Cu and Pb, and the degree of influence expresses as HA> FA> HM.(5) Under the condition of added amount is 10%, in different plant type areas, the effect of FA on Cu shows FA-Phra. Area>FA-Pota. Area>FA-Myri. Area; the effect of HA on the carbonate Cu decrease range shows HA-Pota. Area> HA-Myri. Area> HA-Phra. Area, the effect of HA on Fe/Mn oxide fraction increase range shows HA-Myri. Area> HA-Phra. Area> HA-Pota. Area, the effect of HA on the organic matter bound Cu increase range shows HA-Myri. A> HA-Phra. A> HA-Pota. A; HM-Myri.has pomote effect on exchangeable Cu; HM-Pota. Area has greater reduce on carbonate Cu, and the increase range of organic matter Cu performance the HM-Phra. Area> HM-Pota. Area> HM-Myri. Area.(6) The fractions of redistribution shows, Cd mainly transforms to the exchangeable and carbonate fraction (the sum of exchangeable and carbonate fraction> 90%), Pb mainly transforms to carbonate fraction, it reveals that the potential ecological risk of Cd and Pb is higher than Cu and Zn.