Experimental study on the effect of Ni(II) additive on ammonia escape in CO2 capture using ammonia solution

Based on complex between Ni(II) and free ammonia, the effect of Ni(II) on reducing ammonia escape in CO2 capture was studied in the paper. In the experiments, the ammonia escape in absorption and desorption were measured respectively under different Ni(II) concentrations and temperature. The ammonia escape reduces strongly with increasing concentration of Ni(II) and reduces less strongly after 0.06 mol/L. The additive Ni(II) with 0.06 mol/L could reduce ammonia escape by more than 30%. The ammonia inhibition of Ni(II) increases strongly with rising temperature, however, this also results in significant ammonia loss. CO2 absorption efficiency and CO2 desorption efficiency were measured under different concentrations of Ni(II) and (NH4)(2)SO4/NH4NO3. Adding Ni(II) and (NH4)(2)SO4/NH4NO3 have little impacts on CO2 absorption efficiency and CO2 desorption efficiency. In addition, there was no sediment found in the experiments, therefore additive Ni(II) is not lost so that it can be recirculated and is hopeful to be a choice for inhibition of ammonia escape in CO2 capture using ammonia solution, but the reduction efficiency should be enhanced in further research. (C) 2015 Elsevier Ltd. All rights reserved.