Among numerous carbon capture technologies, adsorption is considered one of the most effective approaches to reduce carbon dioxide (CO2) emissions in the atmosphere. Various modification approaches of adsorbents have been introduced to enhance the CO2 adsorption ability. Recently, an amine such as tetraethylenepentamine (TEPA) has been extensively used as an adsorbent’s promoter because of its high amine density, low viscosity, low cost, and low toxicity properties. This has added an advantage to the adsorbent in terms of economical and environmentally benign. Therefore, it is important to provide the latest review on TEPA-functionalized adsorbents, specifically on the effects of TEPA functionalization, different TEPA loading, diverse adsorption conditions, as well as the structure of adsorbents towards the CO2 adsorption capacity. Different adsorption conditions over a wide range of adsorption temperatures were thoroughly discussed and several recommendations for future studies were also been proposed.

The increase in the concentration of carbon dioxide (CO2) gas in the atmosphere has led to various severe negative consequences. There are numerous methods for the reduction of CO2 that have been introduced such as chemical and physical absorption, organic liquid scrubbing, amine-based absorption, etc. Adsorption by using solid adsorbents is one of the promising methods that has been widely studied by researchers. The performance of the adsorbents can be enhanced by functionalized with diverse types of promoters. This review is discussing the performance of polyethyleneimine (PEI) as a promoter towards the adsorption of CO2. To achieve high effective PEI-adsorbents, the percentage of PEI amine loading, type of porous support, temperature, and different flow conditions are among the important parameters that need to be considered. The chemical stability of PEI can be improved through modification crosslinking of PEI. Hence in this review, the effect of amine loading, porous support, temperature, slow condition and crosslinking of PEI to its CO2 adsorption performance is observed.