Preparation and characterization of bentonite nanocomposites via sol–gel process

Abstract

Different nanocomposites silica-resin based were prepared and characterized in order to achieve a porous monolith that contains bentonite and allows the flow of aqueous systems. The bentonite used to prepare the nanocomposites was a good adsorbent for various molecules in aqueous media in stirred tank reactor. But the challenge was the obtention of porous bentonite composite columns for industrial applications. The primary composite, silica-resin, was prepared by the sol-gel precursor mixture of the tetraethylorthosilicate (TEOS) and a phenolic resin, made up the gel which is then dried and cured at 180 °C. Bentonite was added to the precursor mixture obtaining the, silica-resin-bentonite composite, and also other potencial adsorbent, carbon, was added obtaining the silica-resin-bentonite-carbon composite. The different composites were mineralogical and structurally evaluated by X-ray diffraction, Infrared spectroscopy with Fourier transform, Differential thermal analyses and thermogravimetric analyses. The textural characterization was performed by Adsorption of nitrogen (Sg-BET), Mercury intrusion porosimetry and Scanning electron microscopy. The comparison of the characteristics and properties between the composites evidenced that the addition of bentonite modify the solgel process and interferes in the composite cured process, so that, modify the mesoporosity and macroporosity of the composite. But, there is a maximum clay limit to obtain an homogeneous monolith. The addition of carbon decreases the porosity of the composite to a greater extent when the granulometry is greater.

Activated Bentonite Nanocomposite for the Synthesis of Solketal from Glycerol in the Liquid Phase

“…As can be observed, natural bentonite B (Figure 1a) consists of particles that seem to be formed by several flaky particles stacked together in the form of agglomerates [31]. On the other hand, solid CB (Figure 1b) has smaller particles than B, and they seem to have a sponge-type structure, indicating that the condensation process took place [32]. Finally, the acid treatment generated the disaggregation and decrease in size of the particles, as can be observed in Figure 1c (solid CBA).…”

Optimization of Palm Oil Boiler Ash Biomass Waste as a Source of Silica with Various Preparation Methods

“…The characteristic peaks around 993.0, 977.84, and 722.15 cm -1 are associated with asymmetric strain vibrations (Si-O-Si), in-plane strain vibration (Si-OH) and symmetrical strain vibration of (Si-O-Si), respectively (Rezaei et al, 2014). The signal at 1397.15-1668.18 cm −1 corresponds to the deformation of H 2 O adsorbed between -silicate layers (Legarto et al, 2019). The absorption peak 3381.25-3590.90 cm −1 could be attributed to the hydroxyl vibration due to the hydroxyl ion (Melucci et al, 2019).…”

Preparation and characterization of Bentonite-OPBA nanocomposite as filler

“…The signal at 1637.33 cm −1 corresponds to the deformation of H 2 O (adsorbed between the aluminum-silicate layers). The band at 3630 cm −1 is associated with Al-OH stretching [20].…”