Interaction of copper and zinc with allophane and organic matter in the B horizon of an Andosol

摘要: Summary Andosols developed on basaltic material are naturally rich in metals. Organic matter and allophane, the key colloids of these soils, have a strong affinity for trace metals, but intimately mixed so that speciation metal is difficult to determine. We used three complementary approaches, namely physical fractionation, chemical extraction potentiometric measurement, distinguish them. Physical particle-size separations selective dissolution allophanes organic were combined demonstrate relations between occurrence contents Cu Zn an andic B horizon. About 22% total soil 7% present < 5-μm fraction, associated with or amorphous mineral constituents. To support this association further, mimicked system was demonstrated. An Al-rich allophane synthesized, portion extracted from clay their reactivities towards Cu2+ Zn2+ studied by potentiometry. The two metallic cations displayed specific soluble matter. Furthermore, behaviour copper zinc ternary system, allophane + soluble matter + trace element, revealed synergy surface complexation. use approaches highlighted linkage metals constituents, showed how important colloidal constituents Andosols.