Insights into the physicochemical characteristics from vermiculite to silica nanosheets

• Published in: Applied clay science 2016-11, Vol.132-133, p.17-23
• Main Authors: Wang, Lan, Wang, Xu, Yin, Jiao, Wang, Chuanyi
• Format: Article
• Language: English
• Subjects: Acid-treatment; Hydrochloric acid; Silica nanosheets; Vermiculite
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2016.05.006

Mesoporous silica nanosheets (SiNSs) were prepared from acid-treated vermiculite (Verm). The influences of acid concentration and reaction time on the structural and textural properties of acid-treated samples were investigated. The physicochemical characteristics of SiNSs were studied by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR), N2 adsorption-desorption techniques, zeta potential, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and 29Si and 27Al nuclear magnetic resonance (NMR). XRF study indicated that acid-treatment leads to the removal of the aluminum and magnesium from the octahedral sheets along with other impurities. XRD, SEM and HRTEM measurements supported that treatment with moderate concentrated acid and reaction time favor the formation of translucent and monodispersed SiNSs, which have been reported rarely. Acid-activation with 2M HCl for 12h gave a maximum value of specific surface area (764m2 g−1) with zeta potential of −38.9mV. FTIR and NMR spectroscopic analyses demonstrated the formation of active groups (Si-OH groups) on the surface of SiNSs. The SiNSs thus obtained by acid-treatment can be used as promising catalyst supports, adsorbents, and morphology-controlling reagents of nanomaterials. [Display omitted] •We prepare mesoporous silica nanosheets (SiNSs) from acid-treated vermiculite.•SiNSs show the large SBET of 764 m2 g−1 and low zeta potential of −38.9mV.•Acid-treatment removed the octahedral layer of silicates and endowed more active groups for SiNSs.•SiNSs have translucent and monodispersed morphology.