https://doi.org/10.1016/j.cej.2013.08.116
Different concentrations of Co(II) were studied in the above reference for ammonia escape. The results (Figure 4) showed that it was clear the addition of Co(II) effectively reduced the escape of ammonia. However an optimal concentration of Co(II) should be selected (0.005 mol/L). Too high concentration of Co(II) reduced the effectiveness of ammonia escape.
It is noted that the addition of ions can reduce the availability of ammonia in the solution and thus reduce the capacity of CO2 absorption. In this work, the presence of Co(II) showed little influence on CO2 removal efficiency (Figure 6). It was suggested that the equilibrium of complex formation was reversable, and the complex could be decomposed to facilitate CO2 absorption when the amount of ammonia in the liquid phase was reduced to a certain extent. In addition, the addition of Co(II) showed little influence on the desorption of CO2 (Figure 8).