New evidence for the importance of Mn oxides contributed to nitrobenzene adsorption onto the surficial sediments in Songhua River, China

Abstract

Nitrobenzene at a relatively high concentration was reported to cause an environmental pollution event in Songhua River, China in 2005. The adsorption characteristics of nitrobenzene on the surficial sediments (natural surface coatings) were investigated via a selective extraction – adsorption – statistical analysis method. The experimental results show that the changes in the adsorption potential are not always consistent with the variation of particle structure, suggesting that the effect of removal of some components by extraction or separation procedures on the adsorption potential is much greater than that of variation of particle structure. An additional model analysis indicates that not only organic materials but also Fe oxides, Mn oxides and clay minerals contribute much to the adsorption of nitrobenzene. But the adsorption capacity of Mn oxides on a unit mass basis is the highest, and the lowest for clay minerals except for silicate minerals, implying that the role of organic materials and clay minerals in the solid particles contributed to binding of nitrobenzene is less than that of Fe and Mn oxides, especially the later. The new evidence for the higher adsorption potential of nitrobenzene on the surficial sediments (natural surface coatings) and the more importance of Mn oxides contributed to nitrobenzene adsorption is showed in the present study supposing that the adsorption capacity of solid particles can be divided into several fractions.