Recyclable synthesis of Cs-ABW zeolite nanocrystals from non-reacted mother liquors with excellent catalytic henry reaction performance

Abstract

Nanoscale zeolites are very attractive for advanced applications such as in catalysis, adsorption, supports, sensors and carriers. Green synthesis of these materials is highly appreciated aiming to increase product yield while chemical waste and production cost can be reduced. Here we report high-yield, low-cost and green synthesis of nanosized Cs-ABW zeolite by recycling and using the non-reacted mother liquors waste solutions produced from the hydrothermal Cs-ABW zeolite synthesis. The nanocrystalline Cs-ABW solid product of each successive batch was collected and characterized while the non-reacted mother liquors were recovered and reused for subsequent synthesis of nanozeolites. The synthesized Cs-ABW zeolite nanocrystals from three subsequent cycles possessed fairly similar properties and they exhibited excellent catalytic performance in Henry (nitroaldol) reaction of benzaldehyde and nitroethane thanks to their basic sites, (Si-O-Al)-Cs + , located at the external surface of the zeolite. This approach hence suggests a low-cost and eco-friendly preparation of Cs-ABW zeolite nanocrystals since less chemical waste is disposed while the product yield can be significantly improved which are ideal for industrial scale-up process.

Green Synthesis for MCM-41 and SBA-15 Silica Using the Waste Mother Liquor

“…The direct disposal of the mother liquor will not only lead to the waste of raw materials, but can also cause environmental pollution [12]. Some authors address the reuse and recycling of mother liquor as a raw material for the syntheses of porous materials [13][14][15][16][17][18]. To make synthesis processes more attractive, the principles of green chemistry have been implemented as concepts and actions related to economy, sustainability of resources, and environmental protection [19].…”

Hierarchical Cs–Pollucite Nanozeolite Modified with Novel Organosilane as an Excellent Solid Base Catalyst for Claisen–Schmidt Condensation of Benzaldehyde and Acetophenone

“…The basicity increased to 64.7 (CP-0.3), 69.4 (CP-1.0), and 77.9 μmol g −1 (CP-2.0) when the SBET of the solids increased. Thus, the results show that an addition of TPOAC in the synthesis of hierarchical Cs-pollucite is essential as it enhances the accessible surface area and surface basicity, where the basicity (number of basic sites) of Cs-pollucite, namely (Si-O-Al) − Cs + , is strongly associated with the total accessible surface area of the solids [39]. An attempt to correlate the surface basicity with the amount of TPOAC added and S BET was also made.…”

Clean Synthesis of Ti-MWW by Utilizing the Recycled Mother Liquor

“…Vinaches et al studied the effect of the amount of the mother liquor on the synthesis of MCM-22 and found that the spherical amorphous nanoparticles in the mother liquor accelerated the reaction . Nanocrystalline Cs-ABW zeolite with good catalytic performance for the Henry reaction of benzaldehyde and nitroethane was synthesized by utilizing the mother liquor . Yang et al synthesized pure S-1 from the recycled mother liquor, which not only effectively reduced the cost of S-1 synthesis but also minimized its environmental impact .…”