Heavy metal removal from aqueous solution in sequential fluidized-bed reactors.
In this study, the sequential fluidized bed reactors (FBRs), were used to remove heavy metals including, Cu, Pb, and Ni, from synthetic wastewater. Heavy metals were removed through crystallization of metal carbonate and hydroxide precipitates on the surface of sand grains. The results showed that the influent metal concentration limits in the sequential FBRs were higher than those in the vertical FBRs. The removal efficiency for Cu, Pb, and Ni reached 96%, 93%, and 98% when the influent concentrations were 250 mg l(-1), 130 mg l(-1) and 130 mg l(-1), respectively. The pH value in the effluent of the FBR ranged from 8.7 to 9.1. The amount of metal coated onto the sand surface was determined and it was found that most of the metal ions were collected in the first reactor. The mechanism of heavy metal removal in the sequential FBRs concluded crystallization and filtration.