Mixed micelles-mediated dephenolisation of table olive processing's wastewaters

Abstract

Olive processing wastewaters account for highly pollutant agro-industrial effluents. Their phenolic compounds are responsible for their toxicity. Those natural compounds have to be degraded or recovered before any discharge into the environment. This investigation deals with the extraction and concentration of the phenolic compounds into an aqueous phase using a mixture of nonionic/anionic surfactants. A synergistic effect for the extraction of the natural phenolic compounds was observed when Genapol X-80 was combined with sodium dodecyl sulphate (SDS). For the tested Genapol X-80 concentration (1–5%), a minimum concentration of 2.5 mM SDS was demonstrated to be necessary to reach maximum extraction rates. The extraction efficiencies were only slightly affected by temperatures between 20 and 50 °C. However, the recovery rate of the phenolic compounds increased with the augmentation of the contact time. The pH has also been found to greatly influence the extraction of the phenolic compounds and the coacervate volume fraction. At optimal conditions, the coacervate phase was enriched up to four times whereas the maximum reduction of the phenolic content in the diluted phase reached more than 40% in one step extraction.