Reduction of Chromium in Water and Soil Using a Rhamnolipid Biosurfactant

Abstract

Hexavalent chromium is of great concern as it is highly toxic and carcinogenic. The objective of this study is the reduction of hexavalent chromium to trivalent chromium using the biosurfactant rhamnolipid in both water and soil media. Rhamnolipid is readily biodegradable with a very low environmental impact. Batch experiments were performed to evaluate the feasibility of using rhamnolipid for the removal and reduction of hexavalent chromium from contaminated soil and water. Rhamnolipid concentration, pH and temperature were evaluated and found to affect the reduction efficiency. At a low concentration of Cr (10 ppm), 100% of initial Cr (VI) in water at optimum conditions was reduced., whereas at a higher concentration (400 mg/L) the reduction was lower (24.4%). In the case of soil, rhamnolipid, the reduction trend of the extracted chromium is the same as in water media.