Removal of Selected Pharmaceuticals Using Octolig, a Supported Chelating Agent

The possibility of removing certain pharmaceuticals from wastewater was tested using Octolig, a commercially available material with polyethyldiamine moieties covalently attached to high-surface area silica gel. Selected drugs and drug models were subjected to column chromatography for removal by means of ion encapsulation, the effectiveness of which would depend upon having appropriate anionic functional groups. Removal of methylene blue with quaternary ammonium groups was (statistically) unsuccessful. In contrast, complete success was attained for removal of each of three xanthenylbenzenes (rose bengal, eosin Y, erythrosine) that have both phenolic and carboxylic acid groups, as is the case with two of the top five prescribed drugs in the US. Moreover, quantitative removal was obtained for zinc phthalocyaninetetrasulfonate (ZPS) and lissamine green B, which have sulfonate groups. Finally, quantitative removal was obtained for amoxicillin, one of the top five most prescribed drugs in the US (in 2008).