Selective chemical extraction and separation of Mn, Fe oxides and organic material in natural surface coatings: application to the study of trace metal adsorption mechanism in aquatic environments

To reveal the relative contribution to adsorption of trace metal on mangane se and iron oxides and organic material in natural surface coatings (biofil ms and associated minerals) in aquatic environments, a selective chemical e xtraction technique was employed to separate the metal oxides and organic m aterial prior to the adsorption of trace metals. Surface coatings were coll ected on glass slides in the surface waters of Nanhu Lake (Changchun, Jilin Province, PR China) as an example. After screening different kinds of conv entional extractants of manganese and iron oxides and organic materials use d for separation of heavy metals in soil and sediment, hydroxyl-amine hydro chloride (NH2OH . HCl) was used to extract manganese brides, sodium dithion ite (Na2S2O4) was used to extract both manganese and iron oxides and nitric acid (HNO3) was used to remove all of the materials. Under the experimenta l conditions, the target components were extracted with efficiencies above 91%. This peparation was important for further research of adsorption mecha nism of trace metal on them. (C) 2001 Elsevier Science B.V. All rights rese rved.