Oxidative Degradation of Aminosilica Adsorbents Relevant to Postcombustion CO₂ Capture

Abstract

Coal-fired power plant flue gas exhaust typically contains 3À10% oxygen. While it is known that the monoethanolamine (MEA) oxidative degradation rate is a critical parameter affecting liquid amine absorption processes, the effect of oxygen on the stability of solid amine adsorbents remains unexplored. Here, oxidative degradation of aminosilica materials is studied under accelerated oxidizing conditions to assess the stability of different supported amine structures to oxidizing conditions. Adsorbents constructed using four different silane coupling agents are evaluated, three with a single primary, secondary, or tertiary amine at the end of a propyl surface linker, with the fourth having one secondary propylamine separated from a primary amine by an ethyl linker. Under the experimental conditions used in this study, it was found that both amine type and proximity had a significant effect on oxidative degradation rates. In particular, the supported primary and tertiary amines proved to be stable to the oxidizing conditions used, whereas the secondary amines degraded at elevated treatment temperatures. Because secondary amines are important components of many supported amine adsorbents, it is suggested that the oxidative stability of such species needs to be carefully considered in assessments of postcombustion CO 2 capture processes based on supported amines.

Direct synthesis of single-walled aminoaluminosilicate nanotubes with enhanced molecular adsorption selectivity

“…Single-component gas adsorption measurements via quartz crystal microbalance-based techniques 36 were performed to evaluate the functionality of the ANT material. The CO 2 /N 2 and CO 2 /CH 4 molecular pairs were chosen to assess the effect of the aminomethyl groups on adsorptive selectivity for CO 2 , which is relevant to carbon capture from flue gas and natural gas purification 37,38 . The full adsorption isotherms are shown in Fig.…”

Low concentration CO2 capture using physical adsorbents: Are metal–organic frameworks becoming the new benchmark materials?

“…Only a few works have considered the recyclability and degradation in terms of the stability of CO 2 adsorbents. 6,[13][14][15][16] (vi) Tolerance to impurities: The degree of tolerance and the affinity of the adsorbent to impurities such as moisture and acid gases may significantly affect their use. When materials are affected by such impurities, additional purification steps are required.…”

Sponges with covalently tethered amines for high-efficiency carbon capture

“…11), still well above the reported capacity records of other types of supported amine sorbents 3 . The performance loss of the sorbent under these harsh accelerated aging conditions may be attributed to the oxidative degradation of the amines, and structural changes of the support [37][38][39] , as suggested by the slightly lower BET surface area of the sorbent after the treatment ( Supplementary Fig. 11).…”