A new application of ion exchange films is presented. The films are used in a simple analytical method of directly determining low concentrations of Cu 2, in aqueous solutions, in particular, drinking water.The basis for this new test method is the color and absorption intensity of the ion when adsorbed onto the film. The film takes on the characteristic color of the adsorbed cation, which is concentrated on the film by many orders of magnitude. The linear relationship between absorbance (corrected for variations in film thickness) and solution concentration makes the determinations possible. These determinations agree well with flame atomic absorption determinations.

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A new ion-exchange material [based on poly(acrylic acid)] and some of its analytical applications have been reported. This paper contains data on the ion-exchange properties of the film form of the material and its potential application to the decontamination of wastewater and drinking water. The film has a high exchange capacity of 5−6 mequiv/g and a pK a of 5.7. The calcium form is the most effective for removing metal ions from solution, and the optimum pH range is between 5 and 7. The exchange rates are slower for the film form than for the bead and powder forms of the ion-exchange material; otherwise, the properties are similar. The film is effective when hard water solutions are employed and also when metal ions are in the complex matrix of wastewater from electroplating. The film can be used in flow systems having a flow channel large enough to allow passage of turbid solutions.

The results of Bednorz and Muller [1] and Wu and Chu [2] have stimulated a tremendous volume of research on ceramic superconductors [3–7]. Despite a number of other synthetic techniques, the solid state reaction remains the choice of most workers due to its simplicity [4,5,7]: CuO, Y2O3 and BaCO3 are often used in the powder synthesis of Ba2YCu3O7−x. BaO2 is known to be a useful reagent in the synthesis of compounds containing higher oxidation states of metals [8]. Therefore, in our study of the possible role of Cu3+ in superconducting perovskites, we also use BaO2 in the solid state reaction. This paper compares reaction chemistry, material processing and material characterization using BaCO3or BaO2 in the solid state reaction. We obtain greater mass density, increased sample homogeneity, lower resistance, and improved reproducibility for material prepared using BaO2. We would like to point out that other groups have produced Ba2YCu3O7−x using BaO2 [4,7]; Calestani and Rizzoli have reported a one-step process for producing single crystals of Ba2YCu3O7−x using BaO2 [9].