Comparison of anion removal capacities of Octolig® and Cuprilig

Abstract

Mixtures of sodium salts of phosphate, arsenate, and fluoride were used in chromatography and batch experiments to compare the capacity of two immobilized ligands (IMLIGs) to remove these anions: Octolig® and its copper (II)-based metallolig, Cuprilig. The focus of this study was twofold. First, to find out which material, Octolig® or Cuprilig, would remove these anions most effectively; and secondly to determine the optimal capacity for removal of representative anions. Removal capacity was evaluated by two methods: by chromatography and by a batch method. The methods gave identical results, but the batch method was more convenient. Cuprilig had a lower capacity for removal of phosphate than Octolig®. The capability of Octolig® for removing anions was: phosphate > arsenate > fluoride >>>chloride >>>>bromide. Replication of phosphate removal was good for a given batch of Octolig®. Of three different samples of Octolig®, two seemed to be alike based on the phosphate- removal capacity; the third was different on the basis of a Student's t-test. This distinction indicates the batch procedure could serve as a quality control/assurance technique.

Keywords:

• Octolig®
• Cuprilig
• fluoride
• phosphate
• arsenate
• removal
• capacity
• Quality control/assurance

Acknowledgments

We appreciate technical assistance by Christopher Lizardi at early stages of this work. We thank an anonymous reviewer for helpful comments and suggestions. We also appreciate financial assistance of the USF Honors College, Dr. Naomi Yavneh, Associate Dean and Director, Undergraduate Research.

Notes

*Chromatography: 100 ppm aqueous samples through column (1.9 cm, i.d.) packed with Cuprilig (14, 21, 28 mL) at a rate of 10 mL/min (50-mL aliquots were collected. With the phosphate runs, 28 mL of Octolig® was used.

**Volumes of Cuprilig used were 40, 60, and 80 mL, respectively for the three assays.