PB(II) REMOVAL FROM KAOLINITE BY ELECTROKINETICS

Electro-osmosis tests are conducted on saturated kaolinite specimens loaded with Pb(II) to investigate the efficiency and energy requirements of the process in removing this heavy metal. Kaolinite specimens were loaded with 118-mu-g to 145-mu-g of Pb(II) per gram of dry soil, below the cation-exchange capacity of the mineral. The test results pertaining to the flow and the associated electrochemistry (voltage, current, resistance, pH gradients, and conductivity) are presented. The flow in electro-osmosis with open electrodes is time-dependent, and it is strongly influenced by electrochemistry resulting from the pH gradients. The absorbed Pb(II) was removed 75-95% by the process. The extent of removal is directly related to the pH gradients developed in the process. The total charge passed to remove Pb(II) varied between 1,400 and 2,000 amp-hr per cubic meter of soil. The energy requirement for the removal of Pb(II) in these tests was less than 29 kWh-60 kWh per cubic meter of soil processed.