Removal of Phosphate Ions from Aqueous Solutions by Using Modified Diatomaceous Earth.

Diatomite (DE), Ferrihidrite- modified diatomite (DFe) and microemulsion modified diatomite (DEM) were used for removal of phosphate ions from their aqueous solutions. The diatomite (DE) and the modified diatomite [DFe and DEM] were characterized by X-ray, IR and SEM also surface area was estimated. The results of characterization indicated that, the phosphate ions sorption capacities of diatomite were improved after modifying by ferrihydrite or microemulsion. The surface area of the modified diatomite increased according to DEM > DFe > DE, so the efficiency of removing phosphate ions with DEM was higher than that of DFe and DE. This behavior may due to the difference in the electrostatic force between phosphate ions and the surface of DE, DFe and DEM. Also, it is found that the removal of phosphate ions by the three samples improved by increase the phosphate concentration in the initial solutions.