Chapter 10 - CO2 adsorption by functionalized sorbents

Abstract

The constant increase in greenhouse gases, namely CH4, N2O, and CO2, in the atmosphere is the major cause of the global warming phenomenon. An economical and sustainable CO2 capture technology will enable the industries to use fossil-based fuel while restraining the CO2 emissions into the atmosphere. Among different methods reported for the removal of CO2 from point resources, the CO2 capture by using solid sorbents is considered a promising technology as they are less corrosive, less toxic, and exhibit high CO2 capture efficiency compared to conventional liquid solvents. Further, solid adsorbents demonstrated the ability to substantially reduce the capital and operating costs for CO2 capture process. However, the lack of mechanical and thermal stabilities of a wide range of solid adsorbents reported for CO2 capture till today is a major impediment in order to scale up the materials and demonstrate operating conditions at the plant. Carbonaceous and silica-based materials are some of the suitable alternative sorbents owing to their abundance, low cost, and stability at high temperatures. However, low working capacity of these materials is a major drawback for large-scale production. In order to obtain improved performances of these materials toward CO2 capture, one of the strategies adopted is to functionalize solid adsorbents with different structural moieties that selectively bind to CO2 with optimal adsorption energies. This chapter presents a review of different functionalized sorbents that have shown improved performance than the parent materials. The main focus of this chapter is to summarize the performances of reported functionalized solid adsorbents and to find the challenges and solutions for the future directions.