Phosphate Removal from Aqueous Solution by Hydrous Iron Oxide Freshly Prepared Effects of pH, Iron Concentration and Competitive Ions

In the present work, the phosphate removal by hydrous iron oxide freshly prepared is studied. Experiments were conducted to study the effects of pH, iron concentration and the presence of sulphate, chromate, oxalate and certain metallic ions. Infrared spectroscopic analyses were performed to characterize the mechanism of phosphate interaction with the hydrous oxide in the absence and in the presence of the competitive ions. The results of macroscopic analyses show that the phosphate uptake is related to pH. The effect of iron concentration, suggests a certain saturation of adsorption sites. The effect of oxalate ions is more significant than those of chromate and sulphate ions. The presence of zinc and copper decreases the phosphate removal at pH > 7. In the absence of the other ions, the IR spectra of the solid samples show a broad band in the surrounding of 1030cm-1, characterizing the tetrahedral symmetry of phosphate. Among the studied anions, only chromate has an effect on the mechanism of phosphate ion retention by hydrous iron oxide freshly prepared.