Synthesis and characterization of Benzyl chloride-based hypercrosslinked polymers and its amine-modification as an adsorbent for CO2 capture

As one of the microporous polymers with nano-sized holes, HCPs have attracted much attention in CO2 capture for a variety of reasons such as their low density, high chemical and physical stability and high specific surface area. On the other hand, amine-modification of the adsorbent is known to improve it. Therefore, research on amine-functionalization of adsorbent HCPs is on the rise. The aim of this study was to synthesize benzyl chloride-based hypercrosslinked adsorbent (B-Cl) using the Friedel- Crafts reaction for CO2 adsorption. In addition, it was modified by post-synthesis modification using low-cost wet impregnation process with an amine to improve its adsorption capacity. Post-synthetically functionalized amination was performed using ethylenediamine (EDA) in the presence of water (B-Cl-1) and methanol (B-Cl-2). Structural properties of the adsorbent were depicted by various spectroscopic techniques. A higher specific surface area was reported for B-Cl (1248.87 m(2).g(-1)) compared to the amine-modified samples (B-Cl-1 (1115.08 m(2).g(-1)) and B-Cl-2 (409.49 m(2).g(-1))). The CO2 adsorption capacity of benzyl chloride-based hypercrosslinked (B-Cl) and amine modified samples (B-Cl-1 and B-Cl-2) was evaluated in the different conditions. B-Cl adsorption capacity at (1 bar, 273 K) is 75.14 mg.g(-1), which is higher than the amine modified samples B-Cl-1 (39.15 mg.g(-1)) and B-Cl-2 (19.10 mg.g(-1)). On the other hand, the adsorption capacity of amine-modified adsorbent in the presence of accessible and low-cost water solvent (B-Cl-1) at temperatures above 45 degrees C increased compared to the unmodified adsorbent. In order to better understand the absorption process, experiments were conducted to investigate isotherm, kinetic, and thermodynamic of the process. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study synthesized benzyl chloride-based hypercrosslinked adsorbent using Friedel-Crafts reaction and modified it with amine post-synthesis to improve CO2 adsorption capacity. Results showed higher surface area and CO2 adsorption capacity for benzyl chloride-based adsorbent compared to amine-modified samples. Amination of the adsorbent enhanced adsorption capacity, especially at higher temperatures.