Zeolite A was synthesized using the coal ash from Siderópolis/RS -Brazil. The synthesis was based on a standard IZA synthesis using coal ash as the Si and Al source. XRF analysis showed that the coal ash has a Si/Al ratio of 1.52, which is close to the Si/Al ratio required to produce zeolite A (1.0). The synthesized materials were analyzed by XRD, SEM and N 2 adsorption. More crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 K at the dissolution of NaOH step. The product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours IZA synthesis. The zeolites synthesized by this method had an adsorption capacity of 120 mg.g -1 for Ca 2+ , half the capacity of commercial zeolite A (300 mg.g -1 ). It was not possible to obtain blue or green pigments using the synthesized zeolite A.
Montmorillonite clays are of great interest for industrial processes such as catalysis and adsorption. The textural properties of clays can be modified in an attempt to increase their uses. This paper describes the acid treatment of natural montmorillonite clay. The materials were characterized using X-ray diffraction (XRD), atomic absorption spectroscopy (AA) and BET surface area measurements. Three different acids (HCl, HNO 3 and H 2 SO 4 ) were tested, and HCl and H 2 SO 4 were more efficient for removing Fe from the clay. The results indicate that HCl better preserves the material structure because less Al is removed. A central composite design (CCD) 2 2 was applied to evaluate the treatment using /75 °C, assured that Fe was removed with less damage to the structure.
Here, we present the synthesis and structure determination of the new zeolite ITQ-62. Its structure was determined via ultra-fast electron diffraction tomography and refined using powder XRD data of the calcined material. This new zeolite contains a tridirectional channel system of highly distorted 8-rings, as well as a monodirectional 12-ring channel system.
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