Solid amine sorbents for CO_(2) capture by chemical adsorption: A review

Amines are well-known for their reversible reactions with CO_(2),which make them ideal for CO_(2) capture from several gas streams,including flue gas.In this respect,selective CO_(2) absorption by aqueous alkanolamines is the most mature technology but the process is energy intensive and has also corrosion problems.Both disadvantages can be diminished to a certain extent by chemical adsorption of CO_(2) selectively.The most important element of the chemical adsorption of CO_(2) involves the design and development of a suitable adsorbent which consist of a porous support onto which an amine is attached or immobilized.Such an adsorbent is often called as solid amine sorbent.This review covers solid amine-based studies which are developed and published in recent years.First,the review examines several different types of porous support materials,namely,three mesoporous silica(MCM-41,SBA-15 and KIT-6)and two polymeric supports(PMMA and PS)for CO_(2) adsorption.Emphasis is given to the synthesis,modifications and characterizations-such as BET and PXRD data-of them.Amination of these supports to obtain a solid amine sorbent through impregnation or grafting is reviewed comparatively.Focus is given to the adsorption mechanisms,material characteristics,and synthesis methods which are discussed in detail.Significant amount of original data are also presented which makes this review unique.Finally,relevant CO_(2) adsorption(or equilibrium)capacity data,and cyclic adsorption/desorption performance and stability of important classes of solid amine sorbents are critically reviewed.These include severa PEI or TEPA impregnated adsorbents and APTES-grafted systems.

Activated carbons and amine-modified materials for carbon dioxide capture- a review

Rapidly increasing concentration of CO2 in the atmosphere has drawn more and more attention in recent years, and adsorption has been considered as an effective technology for CO2 capture from the anthropogenic sources. In this paper, the attractive adsorbents including activated carbons and amine-modified materials were mainly reviewed and discussed with particular attention on progress in the adsorbent preparation and C02 adsorption capacity. Carbon materials can be prepared from different precursors including fossil fuels, biomass and resins using the carbonization-activation or only activation process, and activated carbons prepared by KOH activation with high CO2 adsorbed amount were reviewed in the preparation, adsorption capacity as well as the relationship between the pore characteristics and CO2 adsorption. For the amine-modified materials, the physical impregnation and chemical graft of polyethylenimine （PEI） on the different porous materials were introduced in terms of preparation method and adsorption perfor- mance as well as their advantages and disadvantages for CO2 adsorption. In the last section, the issues and prospect of solid adsorbents for CO2 adsorption were summarized, and it is expected that this review will be helpful for the fundamental studies and industrial applications of acti- vated carbons and amine-modified adsorbents for CO2 capture.

Carbon dioxide adsorption/desorption performance of single-and blended-amines-impregnated MCM-41 mesoporous silica in post-combustion carbon capture

High-surface-area,hexagonal-structured mesoporous silica,MCM-41,was synthesized and wet impregnated with three different amines of 2-(ethylamino)ethanol(EAE),ethylenediamine(EDA),and tetraethylenepentamine(TEPA)for use as solid adsorbents in post-combustion CO_(2) capture application.The CO_(2) adsorption test was performed at 25℃and atmospheric pressure using 15/85 vol%of CO_(2)/N2 at a 20-mL/minute flow rate.Desorption was carried out at 100℃under 20 mL/minute of N2 flow.The results show that the capacity and rate of CO_(2) adsorption obtained from all the amine-modified adsorbents were significantly increased with increasing amine loading due to carbamate formation.Desorption efficiency and heat duty for regeneration were also affected by the amount of amine loading.The more stable the carbamate produced,the higher the energy was required.They exhibited the highest adsorption-desorption performance at 60 wt%amines used for impregnation.Blended EAE/TEPA at different weight ratios at a total concentration at 60 wt%amines was impregnated on MCM-41 adsorbent.Sorbent impregnated with 50%/10%of EAE/TEPA showed the best performance of 4.25 mmolCO_(2)/g at a high adsorption rate,a low heat duty of 12 kJ/mmolCO_(2) and with 9.4%reduction of regeneration efficiency after five repeated adsorption-desorption cycles.