**Acknowledgements**

Results of the study with Octolig®, summarized in Table 7 indicate that there was no statisti‐ cally significant difference [59] between the two methods. Similar results were obtained for a capacity for arsenate [59]. The results (Table 7) were also used to see if there was a major difference between different preparations of Octolig® by comparing capacity for phosphate

Phosphate 0.304±0.02 0.299±0.004

Phosphate 0.341±0.06 0.327±0.001

**Table 7.** Selected removal capacities (moles/kg) calculated for phosphate comparing the chromatography method

A *fourth application* is a convenient assessment of the removal of a transition metal by a supported chelator vs sorption on the substrate. It appears that the supported chelators were able to remove copper ion in a quantitative manner, but a goodly proportion (83%) was removed by sorption on silica gel. In contrast, a Linde molecular sieve (alone) with fairly

**Table 8.** Extraction of 5 ppm copper from ammoniacal solution using supported chelating agents and supported

Supported chelating agents can effectively satisfy three needs: concentration for analysis, removal from solution, and removal coupled with regeneration. Their use on a commercial scale has been demonstrated for many years with Chelex as well as Octolig® for removal of transition metals ions and other uses. It seems likely that Octolig® could be competitive with a highly selective ion- exchange resin and, perhaps, commercially competitive, but this remains to be demonstrated. The examples demonstrated indicate a number of chelating agents can be attached using one of three different methods, though covalent attachment seems the easiest

defined pores removed about half of the copper ion through sorption.

**Chelator Support % Removed** LIX® 54 silica gel 97.7±3.3 Oleoylacetone silica gel 100±1.1 ----- silica gel 83.2±2.2 LIX® 54 Linde 3A 89.4±2.2 ------ Linde 3A 42.4±5.5

chelators prepared by the corkscrew method as noted above. Modified from [26] Summary

**Substrate Anion Chromatography\* Batch method\*** Cuprilig Phosphate 0.178±0.003 0.185±0.003

(Sample 1 vs. Sample 2),

142 Column Chromatography

\*Standard method (see text) was used

versus a batch method (= 3) [59]

Octolig® (Sample 1)

Octolig® (Sample 2) I am grateful to the collaborators/co-authors who worked with me over the past two decades. I have valued the association with Mr. Robert L. Alldredge (dec) and Mr. Mark H. Alldredge. I thank Mrs. Barbara B. Martin for helpful comments and encouragement. I am grateful for the encouragement of Ms. Viktorija Zgela.
