Development of an Apparatus for pH-Isolated Electrokinetic In Situ Chemical Oxidation

An apparatus was designed, manufactured, and implemented to isolate pH during electrokinetic in situ chemical oxidation (EK-ISCO). H+ and OH- electromigration were used to determine the adequacy of the designed apparatus for pH isolation. A series of pH-isolation and normal-mode (no pH-isolation) experiments were undertaken and compared. It was found that pH isolation was achieved when the electrode reservoirs were separated by porous media combined with the purging of the electrode reservoir fluid. The electromigration retardation factor of H+ and OH- was calculated for the porous media using the observed pH breakthrough times. The retardation factor for H+ was also calculated by considering mass flux data. The retardation factors for H+ and OH- were found to be 28.3 and 95, respectively, when using the breakthrough time. The retardation factor for H+ was calculated to be 36.7 using the mass flux data.