Abstrait

Kinetics adsorption process of mercury on sediment affected by aquatic dissolved organic matters

Lei Zhang, Lei Zhang

In this experiment, Ruditapes philippinarum and Phragmites communis, the common species in aquatic ecosystems, were used to get two kinds of dissolved organic matter (DOMc and DOMr). These DOM were applied in this study to confirm the influence of DOM prepared from aquatic organisms in kinetics of adsorption of mercury on sediment collected from Jiaozhou bay. The results indicated that the adsorption amount of sample 1# was higher than that in sample 2# in all treatments, due to the higher content of organic matter in sample 1#. The employ of DOM had increased the amount of mercury adsorption into sediment in comparison with that in the groups dealt with de-ionized water, obviously. In the condition of lower mercury concentrations (Hg2+=10 mg/L) and higher mercury concentrations (Hg2+=40 mg/L), the maximum amounts of mercury adsorption of sample controlled with DOMc were137% to 113% higher than these in the same samples dealt with de-ionized water, respectively. And for the treatment of DOMr, the data was 120% to 107%, respectively. The fitting results indicated that the mercury kinetics adsorption process onto sediment better fitted to the equation of y = a-b*c^x in all treatments. Generally, DOM originated from the organism living in the aquatic ecosystem could increase the adsorption amount of mercury onto sediment, which may result in the re-emit of mercury in the sediment up to the overly water body, accordingly increasing the mercury risk in aquatic ecosystem