One Shot of the Hydrothermal Route for the Synthesis of Zeolite LTA Using Kaolin

The zeolite LTA (Z-LTA) was successfully produced from the synthesis of kaolin and well-crystallized using a hydrothermal method. The main purpose of the synthesis Z-LTA from kaolin was to illustrate the transformation Z-LTA with different molarity of alkaline solution and crystallization time. The kaolin was heated in the furnace for 4 h at 500, 600, 700, and 800 degrees C, resulting in a metakaolinization process that transformed it into an amorphous state. The Z-LTA mixture was obtained by dissolving metakaolin in a sodium hydroxide (NaOH) solution without adding other silica or alumina sources. Before going through the hydrothermal synthesis process, the solution mixture was aged for 24 h. The crystal morphology and degree crystallinity (%) of Z-LTA were evaluated using the various molarity (M) of sodium hydroxide (NaOH) and crystallization time (h). The degree crystallinity of the Z-LTA increases from 62.83 to 86.8% when the molarity of NaOH is increased from 0.5 to 1 M but does not increase when the molarity of NaOH is increased to 1 M and 2 M (80.77% and 67.78%), respectively. The degree crystallinity (%) Z-LTA based on molarity proceeded with the various crystallization time (h) factors. 1 M NaOH with 9 h give highest degree crystallinity (88.45%) compared to other time, 12 h (86.16%), 16 h (87.11%), 24 h (86.80%) and 30 h (86.59%) respectively. The crystal morphology structure with Na, Al, O, and Si was seen in SEM images of the Z-LTA at a 1 M NaOH, 9 h crystallization time (Z-LTA, 1 M 9 h). The particle size of (Z-LTA, 1 M 9 h) is smaller, 0.329 mu m, than kaolin, 0.497 mu m. Under low alkali conditions and crystallization time, the hydrothermal process successfully generates high crystallinity from natural kaolin. As a result, low-grade Malaysian kaolin can be successfully transformed into Z-LTA using the traditional hydrothermal process when the composition parameters are carefully controlled. The hydrothermal synthesis from natural kaolin was the most cost-effective and efficient method, with comparable product quality to zeolite synthesized with conventional raw materials.

Automated summary

This study successfully synthesized zeolite LTA (Z-LTA) from kaolin using a hydrothermal method, demonstrating the impact of different alkaline solution concentrations and crystallization times on the transformation of Z-LTA. Under suitable conditions, low-grade kaolin can be transformed into high crystallinity Z-LTA.