"2-4" Binary Skeleton Zeolite Synthesis And Characterization

In this paper, the crystallization conditions of zincosilicate molecular sieve VPI-7 and VPI-8 were systematically investigated by vapor phase transport (VPT) method and hydrothermal method. And a novel molecular-sieve-like microporous silicate material with reversibly cation-exchangeable and selectively adsorptive properties, named as Calcosilicate CAS-1, was first reported and the crystallization conditions were also investigated. The samples were characterized by the XRD, NMR, AAS, SEM, TEM, FT-IR, DT-TGA, BET and chemical analysis.Firstly, the influences of the compositions of reaction mixture, the aging, the liquid phase, temperature and time on the zincosilicate molecular sieve VPI-7 in the reaction system of Na2O-ZnO-SiO2-H2O were systematically studied using VPT and hydrothermal method, respectively. And the crystalline dynamic curves obtained from different conditions were also compared. The experimental results showed that the chemical compositions of gels for synthesizing VPI-7 molecular sieve using VPT method were: (0.35-0.85)Na2O:(0.2-0.4)ZnO:SiO2:(0-6.9)H2O, the H2O, EDA and Et3N etc. may be selected as the liquid phase; those of sols for hydrothermal method were: (0.35-0.65)Na2O:(0.02-0.5)ZnO:SiO2:(5-264)H2O. The room temperature aging speeded up the crystalline reaction rate of both synthesis method and had performed more distinct influences on VPT method than hydrothermal one.Secondly, the influences of alkali, organics, the liquid phase, compositions of reaction mixture, temperature and time on the synthesis of zincosilicate molecular sieve VPI-8 were systematically investigated using both VPT and hydrothermal method in the reaction system of Li2O-ZnO-SiO2-H2O including different organic. The experimental results showed that the compositions of reaction gels for synthesizing VPI-8 molecular sieve using VPT method were:(0.1-0.25)Li2O:(0.02-0.1)ZnO:SiO2: 24.5H2O:(0.2-0.6)TEAOH, the H2O, EDA and EtsN etc. may be selected as the liquid phase; those for hydrothermal method were: (0.1-0.3)Li2O:(0.02-0.1)ZnO:SiO2 : (24.5-120)H2O:(0.1-1.0) TEABr. The characterization results showed that the presence of zinc and organic play an important role in the synthesis of molecular sieve VPI-8 and the ion of organics have different influence on the synthesis of VPI-8 using two synthetic method. With the decreasing of ZnO/SiO2, the shape and dimension of molecular sieve VPI-8 crystals became obviously smaller.Finally, a novel crystal silicate material with properties of molecular sieve, named as calcosilicate CAS-1 (Calcium Silicate No.l) was hydrothermally synthesized in the reaction system of CaO-SiO2-K2O-H2O. The influences of the different alkali, organic, the compositions of raw materials, temperature and time on the synthesis of molecular-sieve-like calcosilicate CAS-1 were also investigated. The experimental results showed that compositions of reaction sols for synthesis of molecular-sieve-like calcosilicate CAS-1 were: (0.2-0.5)K2O:(0.1-0.15)CaO:SiO2: (10-270)H2O. The characterization results showed that calcosilicate CAS-1 was a crystalline material with novel topology structure and a dimensional parallel microporous channel system. The Ca element incorporated in CAS-1 framework was confirmed by chemical analysis and NMR spectra. Just like other zeolite molecular sieves, molecular-sieve-like CAS-1 has reversibly cation-exchangeable and selectively adsorptive properly. As a summary, CAS-1 was the first calcosilicate molecular-sieve-like microporous silicate material with the elementary properties of molecular sieve.