Characterization of non-ionic detergents of the polyethoxylated type from water systems : II. Isolation and examination of polyethoxylated material before and after passage the through a sewage plant

Abstract

The XAD-4 extraction system evaluated in Part I of this series was used to pre-concentrate polyethoxylated material from waste water produced by a small relatively unindustrialized city. Samples were taken from the inlet and outlet of the main sewage plant and the river into which the effluent discharged. A three-stage isolation procedure was developed and the final extract of each sample separated into a non-ionic detergent component and a polyethylene glycol (PEG) component. The concentrations of non-ionic detergent found in the water system were low (less than 1μg ml −1) in the sewage influent and about 100 times lower (approximately 8 ng ml −1) in the river water. Comparing the same samples, the PEG concentration as a percentage of the non-ionic detergent increased from 3% to about 30%. Further characterization of the extracts was attempted using thin-layer chromatography and spectroscopic methods, and two main types were identified in the non-ionic detergent component. These were alkylphenol ethoxylates (APE) and linear aliphatic alcohol ethoxylates, which can be further subdivided into secondary alcohol ethoxylate (SAE) and primay alcohol ethoxylate (PAE). APE was found to be the most persistent, while the aliphatic alcohol ethoxylates broke down much more rapidly in the sewage plant.