Iron Influence in the Aluminosilicate Zeolites Synthesis

Abstract

Abstract--The level of Fe impurities in 2 well-crystallized kaolinites was modified (by addition or chemical removal treatment) to analyze the Fe influence in the aluminosilicate zeolite synthesis.The original and modified clays were heat-treated in order to change their reactivity for zeolite A synthesis, and their thermal transformations were studied by X-ray diffraction (XRD), determination of point of zero charge (PZC) and infrared (IR) techniques. It was established that many structural changes took place, regardless of the Fe clay content. Furthermore, the presence of Fe species in alkaline solution or in the solid phase did not seem to greatly influence the zeolite crystallization, because only small differences in the conversion values among samples with different Fe contents were registered. The crystallization process seemed to be related mainly to A1 coordination changes produced by the thermal and Fe removal treatments used.

Doping and calcination effect on nanostructured aluminosilicates processed by sol-gel route

“…4) [31]. The weak absorption band recoded at 800 cm −1 can be assigned to amorphous silica [32,33] and tetracoordinated aluminium [34].…”

Synthesis of Zeolite A from Metakaolin and Its Application in the Adsorption of Cationic Dyes

“…The zeolites were synthesized through the hydrothermal route, which is a multiphase reaction-crystallization process, as emphasized by several authors [12][13][14][15]20]. This process usually encompasses at least one liquid phase as well as both amorphous and crystalline solid phases.…”

“…For instance, Fe(III) cations, which very often exist as impurities in many zeolites, have been introduced into synthetic zeolites structurally or via cation exchange [14]. The presence of transition metal cations within the structure of a solid matrix can alter the crystallinity of the solid and even hinder clay conversion to zeolites in some cases [15].…”

Synthesis of NaY Zeolite Using Mixed Calcined Kaolins

“…With a SiO 2 /Al 2 O 3 %-mass ratio of 1.64, additional silica is needed for the NaY zeolite synthesis. Furthermore, the low Fe content is beneficial for the NaY zeolite synthesis, as Basaldella has reported [7]. …”