Hierarchical zeolites are materials with a special morphology integrating ordered micropores and mesopores and/or macropores, which have demonstrated their advantages for certain applications in adsorption and catalysis because of the much shorter diffusion length. However, applications of hierarchical zeolites related to ion exchange properties remain unexplored. Herein, we report preparation and characterization of silver-ion exchanged hierarchical zeolite X (Ag-hZX) and also superior silver ion release kinetics of the new material in comparison to conventional microsized counterpart (Ag-mZX). Ag-hZX exhibit 3 times faster release kinetics, and release 2 times amount of silver than Ag-mZX (0.99 and 0.44 mmol/g, respectively). Specifically, Ag-hZX releases 0.90 mmol/g of silver ions within 10 minutes, while Ag-mZX only achieves 0.32 mmol/g in the same period at 5.5 ml/min flow rate. Furthermore, Ag-hZX showed a superior antimicrobial efficacy to Ag-mZX against Methicillin-resistant Staphylococcus aureus (MRSA), an increasingly dangerous and antibiotics-resistant bacterial pathogen. Ag-mZX achieved a viability reduction up to 4 log cells, while only one log cell reduction was observed for Ag-mZX after 3 mins with 100 µg/ml of silver zeolites. Ag-hZX exhibited the same antibacterial activity with 8 to 150 times less products and 12 to 43 times less Ag+ ions. The improved ion exchange property and antibacterial efficacy demonstrate advantages of the hierarchical zeolites as an efficient ion exchanger. More benefits can be anticipated with the addition of mesoporosity for the low silica zeolites as the ion exchangers, molecular sieves and adsorbents which are beyond the catalysis.

Enhanced ion exchange property of hierarchical zeolite X and superior antibacterial performance of silver ion zeolites

254th National Meeting (2017)

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