BIO-SURFACTANT ENHANCED ELECTROKINETIC DECONTAMINATION OF LOW PERMEABILITY MATRICES CONTAMINATED WITH MERCURY

Abstract

The main objective of the present work was to evaluate the efficiency of removal of mercury (Hg) using a novel biosurfactants in order to select the most effective extracting solution for using in electrokinetic (EK) decontamination treatments of polluted marine sediments. In particular, comparative batch tests were performed jointly with technical test in order to optimize the operating conditions of a bench-scale setup designed and carried out for simulating the full-scale decontamination processes. Batch tests were conducted using two esters of glucose as biosurfactants, salt of EDTA and deionized water, at different concentrations. At the same time, it was verified the operation of the setup by conducting a preliminary test EK applying a voltage of 30 V for a treatment time of 30 h.

The main results showed that the maximum Hg removal was achieved with the use of the Olimpicon GC solution. In this case, the Hg extraction was 0,18% (3.6 times higher than that obtained with the 0.2 M EDTA extracting solution of 0,05%). This suggests its application in decontamination treatments aimed at the electrokinetic remediation of Hg-contaminated sediments. The reduction of intensity of current and electroosmotic flow observed with time during the preliminary test EK, highlights the need of using specific conditioning agents. Overall, the data demonstrate the correct working of the experimental apparatus.