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Updated: Aug 14, 2025

Synthesis of Zeolites Using the ADOR Assembly-Disassembly-Organization-Reassembly Route
Published on: April 3, 2016
Synthesis of zeolite A from fly ash and its application in the slow release of urea
Yifei Fan1, Renhe Huang1, Qingyun Liu1
1College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
Abstract:
The study focused on the transformation of coal fly ash to zeolite A (ZA) as a potential carrier for the slow release of urea. After being treated with HCl aqueous solution and NaOH successively, SiO2 and Al2O3 were converted into sodium silicoaluminate. The obtained silicoaluminate was then heated with NaAlO2 in an aqueous NaOH solution at 70-110 °C for 3-18 h and zeolite A was successfully prepared according to the X-ray diffraction measurements. By changing the hydrothermal temperature and time, ZA could reach 237.3 mmol/100 g in maximum cation exchange capacity. ZA impregnated with urea (ZA-U) at a mass ratio of more than 5:1 exhibited slow release of urea and the kinetics release mechanism of ZA-U was proposed. The plant growth test proved that the slow release of urea from ZA-U can promote the growth of maize seedling.
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