[n]‐Oligourea‐Based Green Sorbents with Enhanced CO₂ Sorption Capacity

Abstract

A new series of [n]-oligoureas ([n]-OUs, n=4, 7, 10, and 12) green solid sorbents was prepared following a base-catalyzed, microwave-assisted oligomerization reaction. The materials were characterized by NMR and IR spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and XRD. Decomposition temperatures at 50 % weight loss (Td50 ) were ca. 350 °C for all oligomers. Urea and urethane functional groups indicated by IR spectroscopy confirmed the formation of the sorbent. The CO2 capturing capacities were determined at 35 °C and 1.0 bar (gravimetric method). Accordingly, [10]-OU had the highest CO2 sorption capacity among the others (18.90 and 22.70 mg CO 2 gsorbent (-1) ) at two different activation temperatures (60 or 100 °C, respectively). Chemisorption was the principal mechanism for CO2 capture. Cyclic CO2 sorption/desorption measurements were carried out to test the recyclability of [10]-OU. Activating the sample at 60 °C, three stable CO2 sorption cycles were achieved after running the first cycle.

An investigation of carbon dioxide capture by chitin acetate/DMSO binary system

“…To our knowledge, our report is a second of its kind that shows the importance of oligomeric-based materials rather than a polymeric one for the capturing of CO2. The first report is an augmentation of our work on the sorption of CO2 by [n]-oligourea based sorbent (Qaroush et al, 2015).…”

Inedible saccharides: a platform for CO2 capturing

“…In addition, another good advantage of such materials is their naturally benign-by-design architecture that provides a wide platform to capture CO 2 , ranging from physisorption to chemisorption based mechanisms, dry to wet scrubbing or even the introduction of hybrid materials that can work in parallel with the biopolymers to enhance the CO 2 storage. In our opinion, a strong recommendation for future work is maintained throughout the introduction of oligomers, 29 reported elsewhere as a first generation green sorbent, rather than polymers that can mimic the parent polysaccharides for wet scrubbing applications. “Supramolecular Chemisorption” is further facilitated by other hydrogen-bonding, future candidates of different functionalities.…”

“…A further recommendation is to find universal protocols to capture CO 2 in terms of gas uptake measuring conditions (volumetric vs. gravimetric), as this may hinder a fair comparison among sorbents. 29 Also, modification/functionalisation of the naturally-occurring polymers might provide better reactivities and performance characteristics.…”

“…In the presence of water, a 1 : 1 reaction pathway takes place resulting in the formation of a bicarbonate (RR′NH 2 + – O 2 COH) zwitterionic adduct. 29 – 31 It is noteworthy that this pathway is followed when a benzylic amine ( o , m , p -xylylenediamines) is used. 32 The proposed chemical reaction between amines and CO 2 is summarized in Scheme 3A .…”

A green sorbent for CO2 capture: α-cyclodextrin-based carbonate in DMSO solution

“…The sorption capacities of affiliated systems in the literature were measured using different techniques and sorption conditions, which may hinder a fair comparison among the sorbents investigated by our research group. 17,18 However, it is useful to compare systems that have been measured in the same temperature range with a similar mechanism of action (i.e. chemisorption) to ultimately rank the investigated materials in terms of their potential to capture CO 2 for real-life applications.…”