Dependency of acidic and surficial characteristics of steamed Y zeolite on potentially effective synthesis parameters: Screening, prioritizing and model development

Abstract

There is still no known extensive study prioritizing potentially effective parameters governing NaY zeolite thermochemical treatment process. To fill this knowledge gap, comprehensive investigation of potentially effective parameters of this process affecting the resulting USY zeolite acidic and surficial properties was performed. In this regard, Plackett Burman screening method was used to set up an experimental design. Synthesized NH4+Y zeolite were thermo chemically treated and characterized using XRD, FESEM, nitrogen adsorption-desorption analysis, FTIR spectroscopy and NH3–TPD techniques. The effects of steaming temperature and duration, steam flow rate and partial pressure, steaming repetition and washing EDTA molarity were studied; accordingly, most of them are of great importance. The effective parameters of thermochemical treatment process were prioritized regarding their impact on acidic properties and surficial characteristics of the synthesized USY zeolite as steaming repetition, temperature, washing EDTA molarity, steam partial pressure, duration and steam flow, respectively. Five models were developed, all including six synthesized parameters and the interactions between them. Using the developed prediction expressions, the maximum values for Si to Al molar ratio, acidity, BET surface area, average pore size and pore volume were found to be 11.75 ± 1.19, 4.17 ± 0.47 mmol NH3/g, 739 ± 17 m2/g, 20.7 ± 0.9 Å and 0.351 ± 0.008 cm3/g, respectively.