In the capture of CO2 gas, in relation to CCS, one finds many specific studies where different methods have been reported. It is useful to provide a short review of system studies that specifically apply to CO2 adsorption/absorption capture in the current literature. The aim of this chapter is to provide the reader a more state-of-the-art information. There are two important procedures as reported in the literature that are of main interest (as described in Chapter 2.2 and 2.3):

adsorption of CO2 on solids,

absorption of CO2 in fluids.

Carbon capture technology is based on many different parameters. This means that one needs to apply the most optimum process at each 114individual site. It is useful to describe some typical adsorption and absorption principles (surface chemistry based) from current literature (Figure 5.1). CO2 is soluble in water. However, in aqueous solutions with different solutes (such as aqueous solutions of NaOH or amines), the solubility of CO2 is considerably enhanced. The latter characteristic thus makes the process specific for separation of CO2 from flue gases, with high purity.