Al-Mn-silicate nanobubbles phase as an intermediate in zeolite formation

作者：Bejar Aural; Ben Chaabene Semy; Jaber Maguy; Lambert Jean Francois; Bergaoui Latifa^*

来源：Applied Clay Science, 2016, 123: 202-209.

DOI：10.1016/j.clay.2016.01.025

• Nanobubble
• Analcime
• Manganese silicate
• Kaolinite
• Clay minerals

Manganese (II) carbonate, silicic acid and aluminum nitrate were treated hydrothermally at different temperatures (120-210 degrees C) and for different durations (6-72 h) in an aqueous basic medium. Different compositions of starting mixtures were used. The synthetized materials were characterized by powder X-ray diffraction, FTIR-spectroscopy, N-2 adsorption analysis, Transmission Electron Microscopy (TEM), energy dispersive X-ray analysis (EDX), thermal analysis (TG-DTG), Temperature-programmed reduction (TPR), X-fluorescence, X-ray photoelectron spectroscopy (XPS), electronic paramagnetic resonance (EPR) and Si-29 and (27) Al MAS-NMR spectroscopy. The formation of kaolinite, smectite-like and Mn-containing lamellar phases was observed, but only in minor amounts contrary to previous studies. The majority phase was an original Al-Mn silicate with nanobubble-like morphology, a high surface area and mesoporosity, containing both Mn(IV) in lattice positions and Mn2+ as exchangeable cations. This amorphous Al-Mn-silicate nanobubbles phase seems to be an intermediate in a zeolite formation. Indeed, the increase of the reaction temperature, the reaction time or the reagent concentrations promoted the crystallization of a zeolite of the analcime type by transformation of the Al-Mn-silicate nanobubbles.

• 出版日期2016-4