Synthesis and Characterization of Mesoporous Silica from Anorthite-Clay Mineral: Role of Mechanical Activation

Abstract

Mesoporous silica was prepared from anorthite-clay via mechanical activation (i.e., grinding) and selective acid leaching method. The pore characteristics of the mesoporous silica with different grinding time and acid treatment time were systematically characterized and compared with those prepared via heat treatment followed by acid treatment. Particle size, X-ray diffraction (XRD), BET surface area, thermal gravity (TG), and solubility analyses were carried out to characterize the samples. The XRD results showed that grinding and heat treatment dramatically altered the crystal structure of the samples, resulting in the change in weight loss curves of the corresponding samples from TG analysis. The results for pore size distribution of the prepared samples revealed that acid-treatment led to significant changes in the pore structure of the samples while grinding and heat-treatment without acid-treatment showed negligible influence on the pore structure. More specifically, acidtreatment increased the specific surface area of the ground and heat-treated samples regardless of acid-treatment. Furthermore, solubility tests for anorthite-clay samples showed that there is a positive relationship between the solubility of anorthite-clay and the specific surface area of mesoporous silica, indicating that the increase in the specific surface area of mesoporous silica was attributed to the increase in the solubility of anorthite-clay.

Study of structural properties of acid-treated natural sediment and its application as a sustainable catalyst

“…7. In all DTA curves, a predominantly endothermic peak in the range of approximately 300-400 K can be observed, which is associated with the physisorbed water dehydration and water molecules bonded to exchangeable cations (Panda et al 2010;Choi et al 2014;Temuujin et al 2004;Alver et al 2016). Two endothermic peaks around 800 and 1000 K can also be seen, attributable to dehydroxylation of the coordinated and structural water molecules.…”

Mesoporous Silica Derived from Municipal Solid Waste Incinerator (MSWI) Ash Slag: Synthesis, Characterization and Use as Supports for Au(III) Recovery

“…In general, mechanical activation through grinding changes the surface energy of a target solid material through chemical conversion, such as fracture, amorphization and chemical reactions [35,36]. The energy generated during grinding accumulates on the surface and inside the particle, causing lattice strain and various chemical-phase transformations [35,36]. Therefore, in this study, the XRD patterns of MSWI ash slag activated by grinding at varying times were obtained, as shown in Figure 3b.…”

“…For the non-acid-treated MSWI ash slag, at a grinding time of 64 h, the extracted Si concentrations at 1-4 M NaOH were 1472, 2860, 4780 and 4174 ppm, respectively, being significantly lower than that extracted from the acid-treated MSWI ash slag. In general, mechanical activation through grinding changes the surface energy of a target solid material through chemical conversion, such as fracture, amorphization and chemical reactions [35,36]. The energy generated during grinding accumulates on the surface and inside the particle, causing lattice strain and various chemical-phase transformations [35,36].…”

Improve the Catalytic Activity of Feooh/Bentonite Material by Mechanical Activation

“…Mechanical activation, a green technique used for synthesizing or modifying materials in high-energy ball mill, in essence is a method to change the physical and/or chemical property of materials via mechanical energy [14][15][16] . When the materials was activated in the high-energy ball mill, through the repeated welding and fracturing which happened in the powder particles of material, mechanical activation could increase the specific surface and form the fresh surface areas of the materials, and even destroy the materials' stable crystalline structure [17][18][19][20][21] . The aim of this study is to explore the mechanical activation of FeOOH/ bentonite material.…”