ENHANCEMENT OF ELECTROKINETIC REMOVAL OF SIMAZINE AND CADMIUM FROM CO-CONTAMINATED SOILS BY GLYCINE-β-CYCLODEXTRIN

In this work, enhanced solubilization and desorption behavior of simazine and cadmium by glycine-beta-cyclodextrin (GCD) were investigated, and the feasibility of using GCD in the electrokinetic removal of simazine and cadmium from co-contaminated soil was evaluated. Bench-scale electrokinetic tests were conducted under a voltage gradient of 2.0 V cm(-1) for 10 d, and deionized water, 2g/L GCD and 10 g/L GCD were used as anodic flushing solutions, respectively. The results from solubilization experiments showed that the solubility of simazine in 10 g/L of GCD was enhanced about 23.5-fold, and the apparent aqueous solubilities of cadmium carbonate also increased with increasing GCD concentration. The desorption efficiency of simazine and cadmium in soil increased with increasing GCD concentration. The experimental results from electrokinetic (EK) remediation tests showed that simazine and cadmium migration from soils were significantly affected by GCD concentration and cumulative electroosmoic flow (EOF). The deionized water test without pH control exhibited minimal simaznie migration, however, the maximum simaznie migration was obtained when 2g/L GCD was used as anodic flushing solution. During the test with deionized water, only about 6.5% of simazine was removed from the soil near the anode, when GCD was added to anodic flushing solution, the 2 g/L and 10 g/L GCD flushing solution showed approximately 38% and 52% removal, respectively. In all tests, cadmium migrated from anode to cathode, and accumulated near the cathode due to the high pH, GCD added in anodic purging solution may improve the desorption efficiency of cadmium in soils near the anode and mobilization of cadmium in soils from anode to cathode. This study indicated that the electrokinetic process combined with GCD flushing and pH control may be a good remediation alternative for co-contaminated soil with organic pollutants and heavy metals.