Shaping and silane coating of a diamine-grafted metal-organic framework for improved CO2 capture

Although metal-organic framework (MOF) powders can be successfully shaped by conventional methods, postsynthetic functionalization of the shaped MOFs remains almost unexplored, yet is required to overcome intrinsic limitations, such as CO2 adsorption capacity and stability. Here, we present a scalable synthesis method for Mg2(dobpdc) MOF and its shaped beads, which are obtained by using a spray dry method after mixing Mg2(dobpdc) powders with alumina sol. The synthesized MOF/Al beads have micron-sized diameters with a moderate particle size distribution of 30–70 μm. They also maintain a high mechanical strength. N-ethylethylenediamine (een) functionalization and coating with long alkyl chain silanes results in een-MOF/Al-Si, which exhibits a significant working capacity of >11 wt% CO2 capture and high hydrophobicity. The een-MOF/Al-Si microbeads retain their crystallinity and improved CO2 uptake upon exposure to humid conditions for three days at a desorption temperature of 140 °C.

Characteristics of poly-silicate aluminum sulfate prepared by sol method and its application in Congo red dye wastewater treatment

A novel method for synthesizing poly-silicate aluminum sulfate coagulant (PSAS) using a silica-alumina sol was reported.

Fabrication of α-alumina by a combination of a hydrothermal process and a seeding technique

This paper describes a method for producing [Formula: see text]-Al2O3 at low temperatures by a combination of a hydrothermal process and a seeding technique. White aluminum hydroxide precipitate was prepared by a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. Peptization of the precipitate by acetic acid at room temperature transformed it into a transparent alumina sol. The alumina sol was treated with a hydrothermal process. [Formula: see text]-Al2O3 particles serving as seeds were added to the hydrothermally treated alumina sol. The sol containing the [Formula: see text]-Al2O3 particles was transformed into an [Formula: see text]-Al2O3-seeded alumina gel by drying at room temperature. The non-seeded alumina gel was amorphous or showed fine crystallites and began to crystallize into [Formula: see text]-Al2O3 at 900[Formula: see text]C. The [Formula: see text]-Al2O3-seeding promoted the crystallization of the alumina gel to [Formula: see text]-Al2O3. A remarkable [Formula: see text]-Al2O3 crystallinity was achieved with an increase in [Formula: see text]-Al2O3 particle content by weight in the final seeded alumina gel. For an [Formula: see text]-Al2O3 particle content of 5%, the seeded alumina gel was partially crystallized to [Formula: see text]-Al2O3 by annealing at temperatures as low as 600[Formula: see text]C.