THE ISOLATION AND CHARACTERIZATION OF STABLE METAL-ORGANIC COMPLEXES FROM TROPICAL VOLCANIC SOILS

Abstract

Metal-organic complexes were extracted from six soil samples collected on the Caribbean island of Dominica and from a Canadian Podzol Bh horizon soil sample. Following extraction with dilute base, the metal-organic complexes were purified by dissolution in methanol and prolonged dialysis against distilled water. The complexes were characterized by chemical, IR-spectrophotometric, thermal, and X-ray methods. Between 22.8 and 70.4 percent of the soil C was found to occur in the purified complexes. The most prominent metal in all complexes was Al which constituted between 3.45 and 7.17 percent of the air-dry weights. Other major inorganic constituents were Fe and Si. The Al and Fe in the metal-organic complexes appeared to be present as Al(OH)2+ and Fe (OH)2+, bonded to negatively charged carboxyl and phenolic hydroxyl groups on the ligands. X-ray analysis failed to show any crystallinity in the complexes. The ligands were identified after removal of most of the metals as fulvic acids. © Williams & Wilkins 1975. All Rights Reserved.