An Ultrafast and Green Synthesis of Mesoporous Zeolite X for Great Enhancement in Methylene Blue Adsorption

Abstract

Following the global trend of green material synthesis, the microwave-assisted acid leaching process has significantly reduced the treated time to introduce mesoporosity into zeolite FAU (type X). Instead of hours, mesoporous zeolite has appeared for 5 minutes only. The material's success was demonstrated by various characterizations like the hysteresis loops of the Nitrogen adsorption-desorption curves, the X zeolitic structure through X-ray diffraction (XRD) patterns, and the morphology by scanning electron microscopy (SEM) – energy dispersive X-ray (EDX) spectroscopy analysis. Less than 10 wt% of acetic acid concentration is enough to increase the zeolite's external surface area from 34.4 m2/g to 234.4 m2/g which indicates the formation of mesopores. Intending to enhance mesoporosity while minimizing microporous loss, 0.9 wt% acetic concentration corresponding to 172.6 m2/g external area value and 630 m2/g BET surface area value is prominent in the samples. In addition, mesopore enhancement has played an extreme role in significantly improving the methylene blue adsorption with molecular transport facilitation. Methylene blue adsorption results of all mesoporous zeolites were many times higher (2-6 times) than the original microporous sample under the same adsorption conditions.