Development of Carbon-Based “Molecular Basket” Sorbent for CO₂ Capture

Abstract

The objective of the present study is to develop a new type of “molecular basket” sorbent (MBS) by using inexpensive and commercially available carbon materials instead of mesoporous silica molecular sieves as supports for CO2 capture from flue gas. Several commercial carbon materials, including activated carbons and carbon blacks, with different pore sizes and pore volumes have been used to prepare the carbon-based MBS (CB-MBS) by loading the CO2-philic polyethylenimine (PEI) on them. The CO2 sorption performance of the prepared CB-MBS was evaluated by using a thermogravimetric analyzer and a fixed-bed flow sorption system. Effects of the pore properties of the carbon supports, PEI loading amount, sorption temperature, and moisture on the sorption capacity were examined. A sorption capacity of 135 mg-CO2/g-sorb was obtained by loading 50 wt % PEI on a carbon black, which is almost the same as that of PEI(50)/SBA-15 prepared by loading 50 wt % PEI on SBA-15. The higher CO2 sorption capacity of 154 mg-CO2/g-sorb was achieved when increasing the PEI loading on the carbon black to 65 wt %. Characterization of the porous structure of the carbon materials indicates that the high sorption capacity of the carbon-black-supported PEI sorbents can be ascribed to their high pore volume and large pore size. It was further found that the volume-based capacity of PEI(50)/C4 was even higher than that of PEI(50)/SBA-15 by 57% due to the higher packing density (0.35 g/mL) of the former than that (0.22 g/mL) of the latter. Because of its high CO2 sorption performance and low preparation cost, the carbon-based MBS could be a promising sorbent for cost-efficient CO2 capture from flue gas.

Vapor-enhanced CO2 adsorption mechanism of composite PEI@ZIF-8 modified by polyethyleneimine for CO2/N2 separation

“…The application of some alkaline chemicals to modify the surfaces of conventional adsorbents was an effective approach since CO 2 is acidic molecule [6]. For example, polyethylenimine (PEI) was reported to be grafted or impregnated on conventional porous materials such as activated carbon [7], mesoporous silicas [8], MCM-41 [9], mesoporous alumina [10], clays [11] and chitosan [12]. As a result, CO 2 adsorption capacities of these modified adsorbents had obviously been improved.…”

Amine Functionalization of Microsized and Nanosized Mesoporous Carbons for Carbon Dioxide Capture

“…[13][14][19][20] We thus selected the impregnation method for amino-functionalization of mesoporous carbons in the present work. Ethylenediamine was selected for the chemical grafting via an amide route (-CONH-CH 2 NH 2 ) because (a) it is a well-established animo-functionalization method for carbon materials such as carbon nanotubes 21 and (b) ethylenediamine, similar to PEI, can provide a high content of amino groups that are active CO 2 -adsorption sites.…”

CO2 adsorption and desorption performance of waste ion‐exchange resin‐based activated carbon

“…The common adsorbents used to separate CO 2 from flue gas are porous carbonaceous materials , metal oxides , zeolites , mesoporous silicas , and metal organic frameworks (MOFs) at present. Activated carbon (AC), which is one type of carbonaceous material, is used for CO 2 capture because of its alternative precursors, high surface area, environmental friendliness, low cost, excellent thermal stability, special surface properties, and ability to operate in a wide temperature and pressure range .…”