Computer Simulation Study On Adsorption Of Flue Gas Containing SO₂,H₂S And CO₂ By Charged Carbon Nanotubes

The increasing population of the world has led to an increase in the energy consumption,and the environmental pollution caused by the large amount of flue gas emitted by factories has become increasingly prominent.Since fossil fuels will continue to be the main energy resource long in the future,the capture and separation of harmful components from flue gas has become a very realistic and urgent research topic.In this paper,the adsorption of pure gases SO₂ and H₂S in densely packed single-walled carbon nanotube arrays（SWCNTs）with different extra charges and different nanotube distances,and the adsorption separation of binary mixed gases SO₂/CO₂,H₂S/CO₂,H₂S/SO₂were studied by using grand-canonical Monte Carlo method to simulation:1.The adsorption of pure gases SO₂ and H₂S in SWCNTs with different extra charges and different intertube distances were analyzed and compared to the cases of neutral SWCNTs.It was found that for the inner adsorption of SO₂,charging SWCNTs,especially positively charging,can enhance the adsorption of gas under low pressures.While under high pressures,positively charging can enhance the SO₂adsorption and negatively charging can decrease it when compared to the cases of neutral SWCNTs.After analyzing the adsorption heat,atom density and molecular orientation,it is found that the interaction between SO₂ and SWCNTs and the way of molecular packing both can dominate the change of adsorption.The adsorption is actually the result of the collective effect of these two factors.As for the outer adsorption,it follows the same adsorption mechanism as the inner adsorption.Furthermore,above conclusions are also true for another polar molecule,H₂S,except that the difference of atom charge between H₂S and SO₂ makes the role of SWCNT different.2.Based on the conclusions from the adsorption of pure gases in SWCNTs,the adsorption of binary mixed gases SO₂/CO₂,H₂S/CO₂ and H₂S/SO₂ were simulated and analyzed.It is found that for the binary mixed gases,the adsorption selectivity of SO₂ is larger than that of H₂S and CO₂,and H₂S larger than CO₂.In order to explain and understand these results,the Van der Waals diameter for the atoms in the component molecules should also be considered besides the strength of interaction between SWCNTs and gases and the way of molecular packing as analyzed for the adsorption of pure gases.