Mesoporous silicalite-1 nanospheres and their properties of adsorption and hydrophobicity

Abstract

The mesoporous silicalite-1 nanospheres (MSNs) had been successfully synthesized by using silicalite-1 seeds as silica source, cetyltrimethylammonium bromide (CTAB) as the surfactant and diethyl ether as the cosolvent via a novel and facile approach, which had a structure analogous to HMS materials, but contained sillicalite-1 zeolite as the mesoporous wall. A variety of experimental techniques of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and N 2 adsorption/desorption isotherms had been used to characterize the framework structure, porosity and morphology of this novel mesoporous silicalite-1 nanospheres. The obtained nanospheres had the diameters of 300-500 nm and possessed worm-like porous walls. The MSNs materials exhibited high surface areas and large total pore volumes, and the order of the mesoporous structures increased with the amount of the added cosolvent. Due to the complementary types of porous structures, MSNs materials were used to conduct the adsorption experiments under static and dynamic conditions. The equilibrium adsorptive experiments of toluene for MSNs samples presented a high adsorption capacity compared to the results reported by the other literatures. And the hydrophobicity index (HI) estimated by the dynamic adsorption process under wet conditions indicated that the MSNs materials possessed high dynamic adsorptive capacities and super-hydrophobic properties.

Facile preparation of hierarchically porous diatomite/MFI-type zeolite composites and their performance of benzene adsorption: The effects of NaOH etching pretreatment

“…However, several drawbacks, such as hygroscopicity, pore clogging, and low thermal stability are associated with its use A C C E P T E D M A N U S C R I P T in adsorption processes [10]. Hence, extensive efforts have been focused on finding alternative adsorbents [11][12][13][14][15]. MFI-type zeolites with low Al content or purely siliceous form (silicalite-1) have been proposed as potential adsorbents due to their high hydrophobicity/organophilicity, large surface area, and superior thermal stability [16,17].…”

Dynamic adsorption of toluene on pore-size tuned supermicroporous silicas

“…Since the range of supermicropores [11,12] (d ¼ 0.7e2.0 nm) corresponds to the size of various organic molecules, the confined molecules are strongly trapped due to the overlap of the attractive force from opposing pore walls (micropore filling). Thus, supermicroporous materials are beneficial for dynamic adsorption.…”

A hierarchically porous diatomite/silicalite-1 composite for benzene adsorption/desorption fabricated via a facile pre-modification in situ synthesis route

“…Adsorption capacity [37,38] has been recognized as the most common metric for testing the adsorption performance because of its ease of measurement, whereas the diffusion efficiency and reusability of adsorbents are rarely studied. Fletcher et al [39,40] investigated the adsorption-desorption kinetics for vapors on activated carbon.…”