GLYCINE-β-CYCLODEXTRIN ENHANCED ELECTROKINETIC REMEDIATION OF SOILS CONTAMINATED WITH PHENANTHRENE

Enhanced solubilization and desorption behavior of phenanthrene by glycine-beta-cyclodextrin (G-beta-CD) was investigated, and the feasibility of using G-beta-CD in electrokinetic removal of phenanthrene from 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, 0.05 M Na2CO3/NaHCO3 buffer solution, 0.05 M Na2CO3/NaHCO3 buffer solution containing 2 g/L G-beta-CD and 0.05 M Na2CO3/NaHCO3 buffer solution containing 10 g/L G-beta-CD were used as anodic flushing solutions, respectively. The results from solubilization experiments showed that the solubility of phenanthrene in 30 g/L of G-beta-CD was enhanced about 30-fold. The desorption efficiency of phenanthrene in soil increased with increasing G-beta-CD concentration. The experimental results from electrokinetic (EK) remediation tests showed that phenanthrene migration and removal from soils were significantly affected by G-beta-CD concentration and cumulative electroosmoic flow (EOF). The deionized water test without pH control exhibited minimal phenanthrene migration, however, the maximum phenanthrene migration was obtained when 0.05M Na2CO3/NaHCO3 buffer solution containing 2g/L G-beta-CD was used as anodic flushing solution. In a test with deionized water, only about 2.1% of phenanthrene was removed from the soil near the anode, whereas 13% of phenanthrene was removed using the deionized water test with pH control. When G-beta-CD was added to anodic flushing solution, the 2 g/L and 10 g/L G-beta-CD flushing solution showed approximately 24.8% and 34.3% removal, respectively. Electrokinetic process combined with G-beta-CD flushing and pH buffering may be a good remediation alternative for PAHs contaminant removal from contaminated soil.