Simultaneous removal of cadmium and turbidity in contaminated soil-washing water by DAF and electroflotation.
The removal of cadmium and turbidity from contaminated soil-washing water was studied by dissolved air flotation (DAF) and electroflotation at laboratory scale by using sodium lauryl sulfate (SLS) as an anionic surfactant, and calcium hydroxide (Ca(OH)2) as a coagulant. Using DAF, and in the presence of SLS or Ca(OH)2, the maximum recovery rate of cadmium obtained at a stoichiometric cadmium to collector and coagulant ratio of 1:4.5 was 51.1% and 80.8%, while the removal rate of turbidity was 18.4% and 19.2%. However, satisfactory cadmium and turbidity removal was not obtained by DAF. Much more significant removal of cadmium (100%, not detected in the residual) and turbidity (95.7%) was obtained by electroflotation using an aluminium metal plate as electrode, which generated hydroxide and aluminum ion. As a consequence, electroflotation is considered an effective method to separate cadmium and turbidity from contaminated soil-washing water. The electroflotation process may have practical applications for the removal of other hazardous metals from contaminated soil-washing water.
Park
J
J
School of Civil, Urban and Geosystem Engineering, Seoul National University, Seoul, 151-742, Korea.
Jung
Y
Y
Han
M
M
Lee
S
S
D000388:Air; D002104:Cadmium / Q000302:isolation & purification*; D004560:Electricity; D009391:Nephelometry and Turbidimetry; D010316:Particle Size; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry; D014873:Water Pollutants / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
D013501:Surface-Active Agents; D014873:Water Pollutants; D002104:Cadmium