A POTENTIOMETRIC AND ~(113)Cd NMR STUDY OF CADMIUM COMPLEXATION BY NATURAL ORGANIC MATTER AT TWO DIFFERENT MAGNETIC FIELD STRENGTHS

摘要

When a metal cation is complexed by humic acids,fulvic acids,or natural organic matter(NOM),the metal cation may be coordinated by O-,N-,and/or S-donor atoms.The extent to which two or more metal cations compete for binding sites depends on their respective affinities for the variety of available binding sites within the organic matter.This study investigates the binding of Cd(ll)by NOM,using ~(113)Cd nuclear magnetic resonance(NMR)spectrometry to elucidate the effects of pH and Cd/C ratio on the coordination chemistry of Cd(ll)within this complex mixture of binding sites.