Direct synthesis of alkaline earth metal Ca incorporated KHSi2O5 layered silicate

摘要

Layer-structured potassium hydrogen disilicate (KHSi2O5) containing alkaline earth metal Ca is directly synthesized in an aqueous system. The effects of sal composition and crystallization temperature on final products are investigated in details. Highly crystallized Ca-KHSi2O5 is prepared from the sol with initial composition of 0.15CaO:SiO2:0.4K(2)O:0.1TEAOH:30H(2)O at 493 K for 5 days in a high yield. Ca-KHSi2O5 samples with a wide range of Ca/Si molar ratio from 0 to 0.15 are prepared in the system containing KOH above 423 K. Both altered peak intensity and shifted peak position in XRD pattern as well as the presence of band indexed to Si-O-Ca in Fourier transform infrared spectrum for resultant sample confirm the Ca incorporation. SEM-EDS mappings of the selected sample also disclose that Ca atoms are highly dispersed on the Si matrix. (C) 2015 Elsevier B.V. All rights reserved.