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Utilizing of ash extracted from Iraqi common water reeds as an inexpensive effective silica source in the preparation of ZSM-5 zeolite was investigated for the first time in the present work. This study was conducted using a hydrothermal treatment at autogenous pressure. The molar content of silica (17.84–26.76), sodium oxide (1.71–2.4), water (76.92–304.6), organic template (0.55–2.73), organic solvent (23.46–140.76), and synthesis conditions (crystallization time (24–72 h) and temperature (130–180 °C)) were investigated to obtain high purity ZSM-5 zeolite microspheres. The zeolite samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis by X-Ray (EDAX), N 2 adsorption/desorption isotherms, Thermogravimetric Analyzer (TGA), and Fourier transform infrared spectroscopy (FTIR). XRD pattern of all synthesized samples was compared to XRD pattern of the commercial ZSM-5 zeolite. This work allows using locally available solid waste resulted from a dry natural plant as an inexpensive silica source without using an external source of silica. Also, this is the first report of the direct synthesis of a high purity ZSM-5 zeolite microspheres from common water reeds ash containing highly reactive silica. A gel composition of 2Na 2 O: 26.76SiO 2 : Al 2 O 3 : 2.73TPAOH: 23.46EtOH: 304.6H 2 O gave an outstanding final product of ZSM-5 zeolite microspheres at 180 °C and 27 h. This high crystallinity ZSM-5 zeolite porous microspheres possess Si/Al ratio of 17, a crystal size of 61.419 nm, BET surface area of 277.482 m2/g, a total pore volume of 0.1659 cm3/g, micropore volume of 0.1131 cm3/g, pore width of 5.28 nm, and hierarchical factor of 0.14. Image 1 • High purity ZSM-5 zeolite microspheres can be prepared using the ash extracted from common water reeds (CWRA). • Replacing the toxic chemicals with environmentally friendly silica source. • CWRA allows obtaining high purity ZSM-5 zeolite microspheres using low content of methanol and without the ageing step. • CWRA allows obtaining high purity ZSM-5 zeolite at lower crystallization temperature or shorter crystallization time. [ABSTRACT FROM AUTHOR]

Recent research has demonstrated a new synthesis route for hierarchically porous zeolite composites by mechanical modification of the support surface using ultrasonication in a nanoparticle suspension. It was believed that target zeolites should be added as seeds for the sonication. In this study, the effect of nanoparticles was investigated with ultrasonication to understand the crystallization mechanism of zeolites obtained by the nanoparticles–assisted synthesis. It has been found that the nanoparticles under the influence of ultrasonication generate fissures or cracks as nucleation sites on the carbon surface. These nanoparticles such as zeolite A, γ-Al 2 O 3 , quartz and sand are different from the target zeolite X. Therefore, an amorphous aluminosilicate gel nucleates at those cracks during the hydrothermal treatment. Thus, the mechanical activation of the support surface is the process to induce the formation of strongly attached zeolite X over the template, not a seeding step. This is confirmed as an attachment due to the weak bond between the support and the zeolite for ‘non-seeded’ composites whereas the ‘seeded’ composites have a robust structure which maintains a zeolite coating upon mechanical agitation. [ABSTRACT FROM AUTHOR]

Microwave-assisted synthesis of zirconium (Zr) based metal organic frameworks (MOFs) were performed and the yield and porous property of UiO-67 was optimized by varying the quantity of the modulator (benzoic acid, BenAc and hydrochloric acid, HCl), reaction time and temperature. It was found that ( i ) an increase in the amount of modulator enhanced the specific surface area and pore volume of UiO-67 due to the promotion of linker deficiency; and ( ii ) the presence of modulators influenced the number of nuclei (and hence the crystal size) and nucleation time (and hence the yield). Optimum amounts of BenAc and HCl for synthesizing UiO-67 under microwave irradiation were determined as 40 mol equivalent and 185 mol equivalent (to Zr salt), respectively. In comparison to conventional solvothermal synthesis, which normally takes 24 h, microwave methods promoted faster syntheses with a reaction time of 2–2.5 h (at similar temperatures of 120 °C and 80 °C for BenAc and HCl, respectively). The thermal effect of microwave is believed to contribute to the fast synthesis of UiO-67 in the microwave-assisted synthesis. The reaction mass efficiency and space-time yield show that microwave heating promoted the simple yet highly efficient preparation of Zr-based MOFs. In addition, UiO-67 MOFs from different synthesis methods ( i.e. the microwave-assisted and solvothermal method) were evaluated using single-component (CO 2 and CH 4 ) adsorption, showing comparable gas uptakes. [ABSTRACT FROM AUTHOR]

We report a low-cost, highly energy efficient microwave-assisted chelation (MWAC) method, which enabled the post-synthetic modification of synthetic zeolites for adopting hierarchical structures within minutes. Exemplified by Zeolite Y, hierarchical Y zeolites prepared in this way showed exceptional specific external surface areas of >300 m2 g−1 and mesopore volumes of >0.46 cm3 g−1. Comparative assessments revealed that developed zeolites have shown significantly improved catalytic activities for catalysis involving large substrates, such as catalytic cracking and hydrocracking of plastics. Image 1 • Efficient post-synthetic modification method under microwave irradiation for making hierarchical Y zeolites. • Combination of microwave and chelation to make intracrystalline mesopores in Y zeolites. • The developed method shows significantly reduced energy consumption and improved mesoporosity. • The resulting hierarchical Y zeolites show the improved catalytic activities in catalytic cracking and hydrocracking. [ABSTRACT FROM AUTHOR]

A multiporous zeolite A (A b) was obtained by the addition of the organosilane molecule dimethyl octadecyl [3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC) in the synthesis gel and successfully dispersed in bacterial cellulose forming aerogels for Pb2+ adsorption. Several characterization techniques such as powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N 2 adsorption-desorption were employed to investigate physical, chemical, and textural properties of the samples. The resulting material is also compared to the conventional microporous zeolite A and shows a positive interaction between zeolite crystals and cellulose nanofibrils, specially when the mesopores are present in the crystal. Improvements are observed for the multiporous samples in both adsorption and ionic exchange processes. The selectivity for Pb2+ in the presence of Cd2+ is enhanced as a result of improved intraparticle diffusion where there is the insertion of mesopores to the structures. From the kinetic models, the pseudo-second order model fits better to the experimental data suggesting chemisorption as the governing process in adsorption and the mesopores seem to have a remarkable role on it. These multiporous materials facilitate the access of Pb2+ to the zeolite inner pores and therefore present high potential to be used for both Pb2+ adsorptive and analytical devices. Image 1 • Multiporous zeolite A is successfully obtained by using a bifunctional surfactant. • Hierarchical materials are obtained with Bacterial cellulose nanofibres. • Better selectivity for Pb2+ in binary system with Cd2+ is achieved for the material. • Materials with potential use for both adsorptive and analytical devices. [ABSTRACT FROM AUTHOR]

The application of three-dimensional (3D) pillared-layer metal-organic frameworks (MOFs) M(bdc)(ted) 0.5 (M = Co, Cu, Ni, Zn) in the adsorptive separation of ethane/ethylene (C 2 H 6 /C 2 H 4) mixtures was studied. The effect of the type of metals in M(bdc)(ted) 0.5 on the framework structure regarding the moisture stability and adsorption performance was investigated. M(bdc)(ted) 0.5 MOFs show excellent porous structures with high surface areas of up to 1905 m2/g (M = Ni), as well as being stable under humid conditions (assessed by the dynamic water vapour adsorption tests with maximum 20% relative humidity at 25 °C). M(bdc)(ted) 0.5 exhibits the preferential adsorption of C 2 H 6 over C 2 H 4 under all conditions (i.e. 25–50 °C and 0–10 bar), although a reversal in adsorption uptake (i.e. C 2 H 4 adsorption uptake exceeds the amount adsorbed of C 2 H 6) occurs at pressures of >6 bar. The adsorption capacities of C 2 H 6 and C 2 H 4 on M(bdc)(ted) 0.5 adsorbents are up to 8.63 and 8.79 mmol/g at 25 °C and 10 bar, respectively. The calculated C 2 H 6 /C 2 H 4 selectivity for an equimolar mixture is insensitive to the metal ions in M(bdc)(ted) 0.5 , which varies between 1.4 and 1.9. Dynamic breakthrough experiments show that C 2 H 6 /C 2 H 4 mixture can be separated in a fixed bed packed with Ni(bdc)(ted) 0.5. The good adsorption capacity and selectivity, as well as the low isosteric heat of adsorption, make M(bdc)(ted) 0.5 MOFs, especially Ni(bdc)(ted) 0.5 , good candidates to be further developed for the effective separation of C 2 H 6 /C 2 H 4 mixtures in the presence of water vapour with a relative humidity lower than 30%. Image 1 • Pillared-layer M(bdc)(ted) 0.5 MOFs show selective adsorption of C 2 H 6. • Adsorption capacity of M(bdc)(ted) 0.5 for C 2 H 6 is up to 8.63 mmol/g at 25 °C and 10 bar. • Adsorption capacity, rather than selectivity, of M(bdc)(ted) 0.5 depends on metal ions. • M(bdc)(ted) 0.5 MOFs are moisture-stable at 20% relative humidity at 25 °C. [ABSTRACT FROM AUTHOR]