Zirconium phosphate properties

The main interest in zirconium phosphates relates to their ion-exchange properties. If amorphous zirconium phosphate is equiUbrated with sodium hydroxide to pH 7, one hydrogen is displaced and ZrNaH(P0 2 3H20 [13933-56-7] is obtained. The spacing between the zirconium layers is increased from 0.76 to 1.18 nm, which allows this phosphate to exchange larger ions. 

The properties and behavior of double phosphates such as — Y)3 (216), sodium—zirconium phosphate—siUcates (217), and... 

Layered phosphate/phosphonate and phosphonate materials, obtained by substitution of the phosphate moiety by phosphonate groups, display interesting tunable hydrophilic/organophilic properties for adsorption processes. When Candida rugosa lipase (CRL) is simply equilibrated with zirconium phosphate and phosphonate [135,136], immobilization was demonstrated to take place at the surface of the microcrystals. However, because lipase exhibits a strong hydrophobic character, its uptake by zirconium phosphate and phosphonate was much more related to the hydrophobic/hydrophilic character of the supports than to the surface area properties. A higher uptake is observed for zirconium-phenylphosphonate (78 %)... 

A limited amount of work has been carried out using zirconium phosphates, compounds with well-defined coagulation and adsorption properties. The efficiency of coprecipitation was about 70% for free amino acids and albumin. 

Yang, C., Srinivasan, S., Bocarsly, A. B., Tulyani, S. and Benziger, J. B. 2004. A comparison of physical properties and fuel cell performance of Nafion and zirconium phosphate/Nafion composite membranes. Journal of Membrane Science 237 145-161. 

About 40 years ago, Clearfield and coworkers started a fertile activity in the synthesis and characterization of crystalline zirconium phosphates [136,140,148], After the initial findings, an enormous research effort directed toward the syntheses and characterization and investigation of the properties of the many phases of crystalline zirconium phosphate have been carried out [140], In this regard, it has been shown that, in general, all of the zirconium phosphate phases have excellent ion-exchange properties. 

Advancements in the preparation of new PLS s nearly parallels that of the zeolite and zeolite-like phases. Initially the pillared smectite clays were investigated but the quest for new materials with new properties led to e qiloring the pillaring of other layered phases. These include, most notably, the layered zirconium phosphates, double hydroxides (hydrotalcites), sihcas and metal oxides. The parallel paths of discovery in new material compositions for the layered phases and the microporous (zeoUte) phases are summarized in Table 1. A conq>arison between the pore architectures of the zeohtes and the two dimensional PLS is shown in Table 2. 

Several inorganic ion exchangers like the zirconium salts of phosphates, silicate phosphates, molybdate phosphates, and tungstate phosphates showed selective sorption properties for potassium dissolved in sea water and brines. The potassium capacity of zirconium phosphate was found to be 25 mg K+/g. The selectivity for potassium increased with higher drying temperatures of the exchangers. The potassium ion sorption rate exceeded that of other cations40). 

Ikeda, S., Kondo, T. Kato, S., Ito, K., Nomura, K. and Fujita, Y. (1995) Carbon dioxide sensor using solid electrolytes with zirconium phosphate framework (2). Properties of the CO, gas sensor using Mgi.i5Zr4P5 7810.30,4 as electrolyte. Solid-State Ionics, 79, 354—7. 

An epoxy infiltration process has been used to fabricate zirconium phosphate with much improved physical and mechanical properties for robust applications in various electrochemical devices. Results show that phase composition, microstructure and properties vary gradually along the depth profile, confirming the functionally-graded character of these materials. 

Zirconium phosphates have been extensively investigated as intercalation hosts (531. and the catalytic properties of some pillared zirconium phosphates has been reviewed by Clearfield (541. 

Early work on the exchange properties of amorphous zirconium phosphate has been summarized by Amphlett (29). In addition, Ahrland et al. (13,15) have studied the exchange behavior of representative fission product ions, for which they found an affinity order of UO, Ce, Y " ", Sr +, Cs+, Rb+, Na+, when amorphous gels of high P04/Zr ratios were used. The separation of certain transplutonium ions (250) on amorphous... 

The catalytic properties of metal-zirconium phosphate solid has also been investigated (21, 349). The catalysts were prepared by the ion exchange of zirconium phosphate with copper, nickel, and chromium ions. Cataljdic dehydration of 2-propanol was studied at 160°-350°C, with zirconium phosphate itself giving the highest activity, yielding 97% propylene at 230°-240°C. Introduction of Cu +, Ni +, and Cr " decreased the dehydrating properties, and also decreased the catalytic isomerizing properties when tested with the cyclohexane-methylcyclopentane isomerization. The introduction of copper and nickel improved the dehydration properties of zirconium phosphate when tested on ethylbenzene. 

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