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Zirconium chemicals are used in a wide range of industries, and with advances in modern technology, the diversity of their applications has increased. 1 In particular, tetragonal zirconia is one of the most important zirconium compounds for ceramic use, with excellent mechanical properties, such as high structure toughness, strength, and hardness. 2 We have studied the effective use of some zirconium oxy-salts as a depressive and fluidizing material of ceramic slurries, 3,4 and have developed a new direct-casting method based on aqueous-acidic high solids loading alumina slurries stabilized with zirconium acetate. 5When the slurries were prepared, the concentration of zirconium oxy-salt was an important factor, and a simple and convenient determination of aqueous zirconium was required. However, the determination of zirconium is not very easy because zirconium(IV) has a marked tendency to form polynuclear hydroxy group-bridged zirconium species (polymerization) in aqueous solutions.6 Pilkington et al. mentioned that accurate results in EDTA titration of zirconium could only be obtained after zirconium ions were converted to a depolymerized form. Therefore, we studied a colloidal titration method as a means to measure the concentration of zirconium conveniently as it exists in the aqueous solution in a polynuclear configuration.Colloidal titration is an excellent measurement method for determining the concentration of natural and synthetic polyelectrolytes. [8][9][10][11][12] Titration is based on the reaction between a positively charged polyelectrolyte (polycation) and a negatively charged one (polyanion).When the charges of the polyelectrolytes are neutralized by the addition of oppositely charged polyelectrolytes, the two ployelectrolytes tend to associate and eventually precipitate. According to Terayama, who was the first proposer of colloidal titration, the colloidal titration method has been applied to several poly-charged species, such as proteins and cells. 8 However, their stoichiometries are still not clear. Regarding the reaction between oppositely charged polyelectrolytes, most of the reaction is accurately stoichiometric. As a typical case, an aqueous solution of poly(diallyldimethyl ammonium) chloride (PDADMAC) can be titrated with an aqueous solution of potassium poly(vinyl sulfate) (KPVS) of known concentration. The reaction between oppositely charged polyelectrolytes has been studied on stoichiometry, 9,13-16 the stability constant, 17,18 and the effect of the polymerization degree. 19 A few colloidal titrations were applied to measure metal ions in hydrolyzed, polymeric forms. Kikuchi and Kubota have investigated a chemical reaction of KPVS with a mixture of poly(aluminum chloride), PAC, ([Al2(OH)nCl6-n]m, n = 3, m = 2.5) as an inorganic macromolecule and [2-(diethylamino)ethyl]dextran hydrochloride.The general characteristics of the resultant polyelectrolyte complexes were also studied. 20 Tajima has reported that undeca(11-)tungstocobalt(II)phosphate, [PW11O39Co(H2O)] 5-, was a useful standa...

Zinc Oxide. -Four kinds of fluoresceins are prepared by reacting resorcinol derivatives with phthalic/sulfophthalic anhydrides and applied to the dye-sensitized solar cell with porous ZnO. The relationship between the efficiency and the position of the fluorine atoms is estimated. Among dyes (I) and (II), (I) shows the highest solar-light-to-electricity conversion efficiency. The acidity of the anchoring group, which is originated from the number of the fluorine atoms as well as the difference of the functional group, has an important effect on the amount of dye on ZnO. -(FUNABIKI*, K.; SUGIYAMA, N.; IIDA, H.; JIN, J.-Y.; YOSHIDA, T.; KATO, Y.; MINOURA, H.; MATSUI, M.; J. Fluorine Chem. 127 (2006) 2, 257-262; Dep. Mater. Sci. Technol., Fac. Eng., Gifu Univ., Yanagido, Gifu 501-11, Japan; Eng.) -H. Hoennerscheid 26-156