SOLID-STATE C-13 NMR-STUDIES OF THE INTERACTION OF ACETONE, CARBON-TETRACHLORIDE AND TRICHLOROETHYLENE WITH SOIL COMPONENTS

Solid-state C-13 NMR has been applied to investigate the interaction o f soil components with isotopically-enriched (C-13) organic pollutants - acetone, trichloroethylene and carbon tetrachloride. Acetone was st udied when adsorbed onto bentonite, kaolinite and humic acid. Trichlor oethylene was adsorbed onto kaolinite and bentonite. Carbon tetrachlor ide was adsorbed onto kaolinite, bentonite, humic acid and a whole soi l. The C-13 NMR results show no evidence of covalent bond formation be tween these compounds and soil components under the conditions studied . Substantial chemical shift differences of acetone adsorbed onto thes e various soil materials are related to the strengths of hydrogen bond s between the carbonyl group of acetone and hydroxyl protons presents in the clay or humic structures. For acetone adsorbed onto humic acid, the wide carbonyl peak shows evidence of a broad distribution of chem ical and magnetic environments, e.g. with a distribution of proton-don or hydrogen-bonding sites of the humic structure. The C-13 NMR signal observed for the carbonyl group of acetone adsorbed onto bentonite con sists of narrow and broad components, which might be related to the pr eviously reported multiphase nature of bentonite.