Preparation of a Complex between Zirconium(1V) Oxide Hydrate and Active Carbon and Its Adsorptive Power to Phosphate lonst

Abstract

A complex was prepared from zirconium(W) oxide hydrate (ZrO₂⋅x H₂O) and active carbon, and the adsorptive power of the complex to phosphate ion and organophosphorus compounds was investigeted. A mixture of an aqueous solution of ZrOCl₂⋅8H₂O (3-7 g) and granular active carbon (10 g) was heated at 160°C with the evolution of hydrogen chloride. The solid thus obtained was washed with water in order to hydrolyze the deposited substance on the active carbon to ZrO₂⋅x H₂O, and then dried. The complex obtained had a much greater adsorptive power to orthophosphate ions than that of commercially avilable zirconium oxide hydrate; for example, the amount of phosphate ion adsorbed by ZrO₂⋅x H₂O present in the complex was about 5 times as much as that by the same amount of commercially avilable one. Though surface area and pore volume of the adsorbent thus obtained became smaller than the active carbon itself, the complex was able to adsorb organophosphorus compounds such as tributyl, triethyl phosphates, dibutyl hydrogen phosphate and sodium glycerophosphate. It was believed that tributyl and triethyl phosphates are chiefly adsorbed by active carbon, dibutyl hydrogen phosphate by both ZrO₂⋅x H₂O and active carbon, while water-soluble compounds such as sodium glycerophosphate by ZrO₂⋅x H₂O deposited on active carbon. Effective removal of phosphate ions was also carried out through a column charged with the complex. It was found that the adsorbent could be regenerated by an aqueous solution of sodium hydroxide and hydrochloric acid, and no reduction in adsorptive capacity was observed in repeated 10 runs.