POWDERED ACTIVATED CARBON SEPARATION FROM WATER BY FOAM FLOTATION

Powdered activated carbon was separated from dilute aqueous suspension s (200-1000 mg/L) by foam flotation using surfactants (anionic or cati onic). The effects of surfactant type, pH value of the suspension, ini tial carbon and surfactant concentrations, flotation time, and air flo w rate on the dispersed-air flotation of powdered activation carbon we re investigated. In optimum conditions the powdered activated carbon s eparation was almost complete. The zeta-potential of powdered activate d carbon was also measured in the presence and absence of surfactants. Finally, carbon flotation was examined after the carbon had adsorbed chromate ions from an acidic solution (pH 2). Almost complete separati on of Cr(VI)-loaded carbon was obtained by using an anionic surfactant .