NMR MICROSCOPY OF HEAVY-METAL ABSORPTION IN CALCIUM ALGINATE BEADS

In recent years, heavy metal uptake by biopolymer gels, such as Cal-al ginate or chitosan, has been studied by various methods. This is of in terest because such materials might be an alternative to synthetical i on-exchange resins in the treatment of industrial waste waters. Most o f the work done in this field consisted of studies of equilibirum abso rption of different heavy metal ions with dependence on various experi mental parameters. In some publications, the kinetics of absorption we re studied, too. However, no experiments on the spatial distribution o f heavy metals during the absorption process are known to us. Using Cu as an example, it is demonstrated in this article that NMR microscopy is an appropriate tool for such studies. By the method presented here , it is possible to monitor the spatial distribution of heavy metal io ns with a time resolution of about 5 min and a spatial resolution of 1 00 mu m or even better.