Ultrasound Assisted Removal of Unstable Form of Cu and Ni from Contaminated Soil
Heavy metals exist in different forms in polluted soils however only the unstable form is bioavailable and potentially threatening to the environment. This study adopted the ultrasound technique as a tool to transform the unstable heavy metal forms into soluble forms and remove them. Acoustic cavitation coupled with mechanical stirring was used to facilitate the removal of Cu and Ni from a polluted soil. Effect of sonication treating time, sonication power and slurry concentration factors on the removal efficiency (RE) were studied. Test results show that the RE increase with sonication treating time, the best RE for Cu and Ni are 40-50 minutes and 30-40 minutes respectively. Increasing the sonication power can improve the removal of Cu but particularly for Ni, the optimal sonication power is 400W. High concentration slurry is better for Cu removal but for Ni, a more dilute slurry is more effective.