The fluidized-bed crystallization (FBC) removes heavy metals onto the fluidized pellets, which is an outstanding alternative to the precipitation method. This study simultaneously recovers iron and copper as binary metal-oxide pellets (FeIII0.66CuI0.33 @SiO2) in a synthetic wastewater using FBC and silica as a seed material. The operating parameters for FBC include the Fe/Cu ratio, pH, cross-sectional loading (L, kg/m2.h) and bed height (H, cm) and these are optimized to maximize the crystallization efficiency of iron and copper. At pH = 8, an input Fe/Cu ratio = 2 at a total metal concentration of 3 mM, the crystallization ratio (CR) and the total respective metal removal (TR) for Fe and Cu is 90% and 99%. Precipitation rates of 0.88 and 0.38 mg-metal/gr-seed•h were obtained at respective cross-sectional loadings of 0.25 kg m-2•h and 0.15 kg m-2•h for Fe and Cu. The crystal phases of FBC product are respectively characterized as FeOOH and Cu2O by XRD analysis. The high crystallization ratio and the recovery of crystal pellet product indicated that the quantity of the sludge has been reduced significantly in comparison to the traditional chemical precipitation.
All Science Journal Classification (ASJC) codes
- Chemical Engineering (miscellaneous)
- Waste Management and Disposal
- Process Chemistry and Technology