Synthesis and characterization of organoamine-functionalized amorphous silica materials for CO₂-selective membranes

Abstract

Amorphous silica-based organoamine-functionalized hybrid materials were designed through polymer-derived ceramics (PDCs) route, in order to selectively transport CO 2 . Silicon-based perhydropolysilazane (PHPS) polymer was chemically modified with an alkylamino silane derivative, and subsequently oxidized in air at room temperature to afford organoamine-functionalized silica. The effect of the organoamine functionalization in the powdered sample as well as for the membrane is discussed with regard to the pure PHPS-derived amorphous silica.

Polymer-derived organoamine-functionalized amorphous silica materials for CO₂ capture

“…As one of promising synthetic routes in order to overcome these limitations, we have recently reported synthesis of amorphous silica-based hybrid membranes 8) through the polymerderived ceramics (PDCs) route. 14) Alkylamine-functionalized amorphous silica hybrid materials were successfully synthesized by chemical modification of a commercially available perhydropoysilazane (PHPS) with (3-trimethoxysilyl propyl) diethylenetriamine followed by room temperature oxidation.…”

“…CO 2 -permselectivities to other gas molecules such as nitrogen and helium were also achieved for the PHPS-derived alkylamine-functionalized silica membrane fabricated on a mesoporous £-aluminamodified macroporous ¡-alumina, which showing this PDCs route has the potential to open a new field of study for the development of CO 2 -selective ceramic-based facilitated transport membranes. 8) To enhance the CO 2 -selective membrane performance, it is essential to recognize the relationships between the nature of functionalized amino group, CO 2 uptake properties, permeation condition such as temperature and humidity, and the resulting facilitated transport CO 2 perm-selectivity. However, the alikylamine functionalized in our previous study was complicated, consisting of one primary amino group and two secondary amino groups [(CH 2 ) 3 NHCH 2 CH 2 NHCH 2 CH 2 NH 2 ].…”

“…8) After cooling down to room temperature, the mixture was poured into a Teflon plate to evaporate the reaction solvents. After subsequent room temperature oxidation in air for 5 h, the amorphous silica-based white powder was ground using a mortar and a pestle, then dried at 120°C in air.…”

“…Dry CO 2 was used for the runs and high purity Ar was used as the purging gas for sorbent regeneration. According to the published procedure, 8) CO 2 adsorptiondesorption measurements were conducted under continuous run at 40°C Ar (40 min), CO 2 (40 min) then Ar (40 min), respectively. In a typical experimental procedure, a sample weight of ca.…”

“…The corresponding CO 2 capture capacities were normalized by the SSA of the samples. 8) Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analyses were carried out using a diffuse reflectance sample holder coupled with an environmental temperature chamber (Model HC900, S. T. Japan Inc., Tokyo, Japan) mounted on a FT-IR spectrometer (Model spectrumTM100, Perkin Elmer Japan Co., Ltd., Tokyo, Japan). Within the chamber, the sample was kept under Ar atmosphere at 40°C for 40 min, and FT-IR spectrum was recorded to characterize the initial state of the sample surface.…”