The influence of l-lysine and PDADMA on the crystal size and porosity of zeolite Y material

The influence of l-lysine, one of the most basic amino acids, and poly(diallyldimethylammonium) (PDADMA) poly(cations) with different molecular weights on the zeolite Y crystal size and porosity was evaluated by using a high-throughput experiment (HTE) approach, allowing the exploration of a wide range of organic compound concentrations under the same experimental conditions. Depending on their nature and molecular weight, the increased concentration of these organic compounds into the synthesis gel gradually delays the crystallization of the zeolite Y. An intermediate molar content of the amino acid (1 l-lysine:9 SiO2) led to slight decrease of the crystallization rate and a significant reduction of the crystal size down to 300 nm. Thus, the l-lysine is assumed to act as a growth inhibitor. The addition of poly(cations) to the synthesis gel results in the creation of silica-rich mesoporous particles forming aggregates. The PDADMA is mainly located in the silica-rich particles and favor their formation along with their mesoporosity. The larger crystal size is attributed to the inhibition of the nucleation process by the poly(cations).

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► HTE approach was used to evaluate the influence of organic compounds on zeolite Y crystals.
► l-lysine acts as a growth inhibitor on zeolite Y with a 30% crystal size reduction.
► PDADMA favors the formation of silica-rich mesoporous aggregates.
► PDADMA is mainly located in the aggregates.