This study illustrates, and compares the results of the removal of phosphate
ions from aqueous solutions by using substances that have affinity to these ions,
i.e., these ions have relatively a high adsorbing tendency toward these
substances. Thre
e different adsorbing substances were used, they are alumina,
synthesized gatite, and hydrotalcite (abbreviation: HT). The results showed
that chemical equilibrium was achieved quickly in the case of HT. Regarding
the relative adsorbing ability of these three substances toward phosphate, and
its removal from aqueous solutions, it was found that both synthesized gatite,
and ignited HT at 500°C were both effective. The removal of phosphate ions
was maximum at pH=5. Ionic strength showed a positive effect on the
adsorption efficiency. The maximum adsorbing ability of these two adsorbing
materials was about 150 mg PO3
-4-P per gram of the adsorbing HT; whereas
the minimum efficiency was for aluminum oxide.
