SYNTHESIS AND CHARACTERIZATION OF ION EXCHANGE PROPERTIES OF SPHERICALLY GRANULATED TITANIUM PHOSPHATE

Abstract

Spherically granulated titanium phosphate of formula TiO_1.25(OH)(_0.47(H₂PO₄) _0.77(HPO₄) _0.13-2.3H₂O (THP) was synthesized by a gel method. The material was characterized by chemical analysis, X-ray diffraction, TGA and ₃₁P MAS NMR spectroscopy methods. Ion exchange of alkali, alkaline earth and some other di- and trivalent metal cations by THP was studied in both batch and column conditions. It was found that THP is a weak acid cation exchanger with a maximum ion exchange capacity of 4.7 meq/g. It exhibits a high affinity for heavy metal cations (Pb²⁺ Cr³⁺, Ba²⁺, Cs⁺ ). Exchange of micro amounts of some polyvalent cations was studied on salt forms (Na, K) of THP. It was shown that the conversion of the exchanger into the salt form enhances significantly its ion exchange performance for transition and heavy metal cations. THP converted into Na⁺ or K⁻ ion