No abstract

Ethanol can serve as an organic additive in zeolite synthesis due to the ease of availability and simple removal. It can influence the crystallization leading to zeolites with different phases and morphology. This study explores the effect of partial displacement of water in the synthesis gel of zeolite NaX by various amounts of ethanol. With one-pot synthesis, the gels with different ethanol/water molar ratios are crystallized 90 °C for 18 h under a static condition. The products are characterized by several techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy (SEM and TEM), nitrogen sorption analysis, inductively coupled plasma-optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA). The ethanol/water molar ratio of 0.045 produces EMT/FAU intergrowth with a hollow structure and undefined shapes. The ratios of 0.412 and 0.628 give the aggregates of nanocrystalline SOD zeolite. Moreover, the molar ratios of 0.101, 0.174 and 0.273 provide a mixture of the three phases. All zeolite products contain both intrinsic micropores and interparticle mesopores. The higher ethanol/water molar ratio in the gel produces the zeolites with the lower Si/Al ratio due to the higher Al incorporation in the zeolite structure. In summary, we demonstrate alternative template-free approaches to synthesize EMT/FAU intergrowth and nanosized SOD zeolite with short crystallization time and low crystallization temperature. The finding is an example of ethanol influence on the crystallization to control the phase and morphology of zeolite.

The goal of this work is to synthesize zeolite NaY inside Lead tree wood. The wood is mixed with zeolite seed gel before mixing with feed gel and subsequent hydrothermal treatment. In the first trial, the dried and untreated Lead tree wood is mixed with the gel of zeolite NaY before the hydrothermal process. Only zeolite NaP is produced. Then, sonication is applied to the wood and zeolite gel mixture before the hydrothermal process. The product is mixed with the phase of NaP and NaY. In the next attempt, the wood is treated with acid reflux before mixing with the zeolite seed gel. NaY is successfully produced inside the wood. When sonication is also applied, the amount of NaY is increased. The presence of zeolites in the wood are confirmed by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, and thermogravimetric analysis. Moreover, the composites are tested for the adsorption of nickel (II) ions from aqueous solutions. The novel Lead tree wood-zeolite NaY composite has the potential as an adsorbent which could be separated easily from the liquid media.

The gel of zeolite NaY has potential as a precursor of other zeolites. The particular interest in this work is to convert the gel of NaY to NaP2. We found that the pure phase NaP2 can be produced simply by the conventional hydrothermal (CH) method at 150 °C for 24 h. This NaP2 sample, named CH150, has an average particle size of 10.3 µm and an Si/Al ratio of 1.82. In the case of single crystallization via microwave-assisted hydrothermal (MH) method, various parameters were studied, including the crystallization temperature (90, 150, 175 °C) and time (15, 30, 45, 60 min). The samples were analyzed by X-ray diffraction and scanning electron microscopy. However, mixed phases of P1 and P2 or ANA were obtained from all samples. Another attempt was made by a double crystallization via MH method as followed: at 90 °C for 1 h, quickly cooled down to room temperature in the microwave chamber and aged for 23 h, and finally at 150 °C for 1 h. The sample, named MH90A150, has an average crystal size of 16.45 µm and an Si/Al ratio of 1.85. The high Al content of NaP2 in both samples (CH150 and MH90A150) could lead to interesting applications.