NaA ZEOLITE SYNTHESIZED OVER FIBERGLASS AS A STRATEGY FOR OPTIMIZING HARD WATER SOFTENING. Zeolite NaA has been successfully synthesized over glass fiber surface previously activated by alkaline treatment. By varying the time of the treatment and the amount of silica and alumina precursors used in the reaction mixture, a sample with higher zeolite concentration could be obtained. This material was evaluated for water softening process as an alternative substitute for the use of the zeolite in its powder form, in which several drawbacks related to recovery and reuse limit its application. Water softening experiments, carried out in a continuous flow system, with a column containing the glass fiber-zeolite NaA, showed high performance in decreasing the Ca2+ ions, with complete removal achieved for 20 mL of simulated hard water (Ca2+ 100.0 mg L-1) by using 200 mg of the sample in form of column (10 mm diameter × 300 mm high). The sample maintained this performance in a wide range of pH (3.0-9.0), and also presented a feasible regenerability, with no decrease in its performance during the first four cycles of use, reaching 87.3% of efficiency over the tenth cycle.

Coprecipitation is one of the most practical methods used to synthesize ferrite nanoparticles. Fine characteristics of these materials can be improved by means of a series of modifications in the synthesis method. In this paper we present a study of influence of glycerol as structure directing and stabilizing agent in the synthesis of zinc ferrite nanoparticle, exploring its chelating capacity and oxidation. The studied materials include two series of zinc ferrite samples and its precursors obtained with or without glycerol throughout different stages during the synthesis process. The structural and morphological characteristics were evaluated by means of different techniques such as X-ray diffraction, Fourier transformed infrared spectroscopy, scanning and transmission electron microscopy and thermal analysis. The oxidation of glycerol was determined by high-performance liquid chromatograph. The obtained results demonstrate that zinc ferrite crystals synthesized in the presence of glycerol are initially bigger than those synthesized in absence of it, but according to the oxidation process they tend to decrease giving rise to intermediate phases. Interestingly, these samples grow back during more advanced stages and become structurally better organized, compared to the series of samples produced in absence of glycerol. These results indicate that glycerol is capable to modify the synthesis route of zinc ferrite nanoparticles via coprecipitation, acting directly over the size and morphology of the crystals.