Evaluation of hydrophilic-hydrophobic character of zeolites by measurements of their immersional heats in water

A Study on the Surface Silanol Groups Developed by Hydrothermal and Acid Treatment of Faujasite Type Zeolites

“…For immersional heat measurement approximately 200 mg of the sample taken in a Pyrex glass ampoule was pretreated at 373 to 773 K and 1 mPa for 5 h. Immersional heats were measured at 298 K with a twin conduction type calorimeter (Tokyo Riko Co.) according to a procedure similar to the one reported elsewhere (26,27). Figure 3 presents the IR spectra at room temperature in the OH region of various samples pretreated at 673 K and 1 mPa for 5 h. In any spectrum after the pretreatment under these conditions, no absorption band due to bending vibration of water molecules was detected in the vicinity of 1630 cm Ϫ1 , which confirmed that no adsorbed water did exist.…”

Synthesis and characterization of novel SiO2 and TiO2 co-pillared montmorillonite composite for adsorption and photocatalytic degradation of hydrophobic organic pollutants in water

“…It is also reported that the hydrophilicity of zeolites decreased significantly after Si 4+ treatment [21] and the zeolites with a high Si/Al ratio became more hydrophobic [22]. Thus, with the increase of the SiO 2 content in the pillared montmorillonites, the hydrophobicity of the pillared montmorillonites will be enhanced, which results in the increase of adsorption capacity for hydrophobic TCP with the order of TiPM < SiTiPM 12 < SiTiPM 11 < SiTiPM 21 ity because SiO 2 is a dominant chemical composite [9] and polar structure [23]. In other words, the higher content of SiO 2 can lead to the stronger polarity of pillared montmorillonite.…”

“…46-1045), are weakened remarkably for the pillared montmorillonites, implying that the layer structures of these pillared montmorillonites are almost destroyed and SiO 2 pillars existed in amorphous phase. No obvious diffraction peaks of TiO 2 anatase (2Â = 25.3 • ) can be found in XRD patterns of both SiTiPM 21 and SiTiPM 11 samples possibly because the contents of TiO 2 in these two pillared montmorillonites are too low to be detected by the XRD [9]. With the increase of the TiO 2 content, an obvious anatase characteristic peak at 2Â = 25.3 • can be observed for SiTiPM 12 .…”

“…As for SiTiPM, it was prepared by mixing 1 wt% NaPM suspension with TiO 2 sol and SiO 2 sol with the molar ratios of 2:1, 1:1 and 1:2. The wet solid was obtained after centrifugation and triplet washing with deionized water, and then was dried at 100 • C and finally calcinated at 450 • C for 4 h. These three prepared SiTiPM were labeled as SiTiPM 21 , SiTiPM 11 and SiTiPM 12 , respectively.…”

Adsorption of Cationic Surfactants on Hydrophobic Mordenites of Different Si/Al Ratio

“…On the other hand, zeolites with a 350 m 2 g 01 for HSZ-2, and 340 m 2 g 01 for HSZ-3 by BET high Si/Al ratio increased the hydrophobic property, weak-analysis of their nitrogen adsorption curves. Pyrene was ened the interaction with water, and adsorbed surfactant of twice recrystallized from ethanol and used for probing the even anionic charge (6)(7)(8).…”