Synthesis of Meso/Macroporous γ‐Alumina via Aluminum Pellet with Controllable Porosity: Ammonium Bicarbonate Influences through Drying and Calcination Steps

Abstract

Mesoporous and macroporous γ‐alumina have been synthesized using the economic source of aluminum pellets. To manipulate the porosity and overall porous characteristics, ammonium bicarbonate was incorporated into the gel and studied to determine its influence on the porous structure of the obtained γ‐alumina. The nanostructure of the synthesized γ‐alumina, characterized by the N2 sorption isotherms and FESEM analysis, indicated that the γ‐alumina of desired pore size distribution could be achieved using such economical source of aluminum when ammonium bicarbonate was considered to tailor its porous structure. The formation of macropores in synthesized γ‐alumina was confirmed by the FESEM images and the crystalline structure of the γ‐alumina of optimal porous structure was revealed via X‐ray diffraction pattern. Before and after being calcinated at 500 °C, TG‐DTA and FT‐IR analyses were also conducted to better assess the impact that thermal processes could have on ultimate γ‐alumina porous characteristics. Considering the embedded ammonium bicarbonate expander, a two‐step mechanism was finally proposed to explain the observed porosity developed through heating stages. Different porosity patterns developed through drying and calcination steps were then contributed to the reactions taking place at each, and N2 sorption isotherms, as well as the FESEM images, were used to evaluate the introduced pore forming mechanisms.

Development of a New Ternary Al2O3–HAP–Pd Catalyst for Diethyl Ether and Ethylene Production Using the Preferential Dehydration of Ethanol

“…00-010-0425 (face-centered cubic structure) in the International Centre for Diffraction Data (ICDD) database. 26 The bare HAP catalyst flourished sharp peaks at 26, 30, 32, 33, and 49°, which is confirmed by the existence of the main diffraction peaks of hydroxyapatite identified based on JCPDS file no. 09-0432.…”

“…The characteristic sharp peaks of the bare Al 2 O 3 catalyst are located at 2θ values of 37° (311 reflection), 46° (400 reflection), and 67° (440 reflection) which is in agreement with the database standard for gamma-alumina structure JCPDS file no. 00-010-0425 (face-centered cubic structure) in the International Centre for Diffraction Data (ICDD) database . The bare HAP catalyst flourished sharp peaks at 26, 30, 32, 33, and 49°, which is confirmed by the existence of the main diffraction peaks of hydroxyapatite identified based on JCPDS file no.…”

The Fabrication, Drug Loading, and Release Behavior of Porous Mannitol

“…During particle preparation, pores are formed when poreforming agents are removed from the solid matrix using high-temperature gas generation or sublimation [12]. Common pore-forming agents include ammonium bicarbonate (NH 4 HCO 3 ), sodium bicarbonate (NaHCO 3 ), camphor, menthol, and thymol [13][14][15][16], of which camphor, menthol, and thymol are insoluble in water, and their pore-forming principle is that they sublimate slowly to produce pores [17]; it is difficult for them to be completely removed. Furthermore, these three pore-forming agents are pharmacologically active, which will further cause problems related to drug safety and effectiveness.…”