*Storage of Natural Gas by CNTs DOI: http://dx.doi.org/10.5772/intechopen.103814*

increased both CO2 uptake and N2-CO2 uptake. Negative charges in a neutral CNT lead to weaker CO2-N2 uptake. Undoubtedly, charge distribution, both on CNTs and on adsorbent molecules, plays an important role in the uptake of gases into pregnant CNTs. In this work, they performed a large Monte Carlo simulation to evaluate the absorption and separation of dual gas mixtures of CO2, SO2, and H2S in neutralized and charged. Carbon nanotubes at low pressure and 303 K at SWCNT with a diameter of 2.17, 2.71, and 3.26 nm and inter-tube distance of 1.0 nm were modeled. Certain loads from -0.04 q to +0.04 q were placed on each nanotube to investigate the effect of the load. It has been shown that the behavior of mixed gases in pregnant SWCNTs follows the same rules as pure gases. Due to the additional strong coulomb force between the adsorbent and the charged SWCNTs, the amount of polar molecule adsorption increases significantly when mixed with CO2, while CO2 adsorption is usually suppressed as a result of adsorption competition [3]. In addition to the general change in local charge distribution by doping or cavitation, electric oscillation absorption (ESA) provides another way to increase gas absorption by carbon-based adsorbents. Therefore, non-fading electric charges on the absorber can be generated and removed by charging and discharging and enable the rapid absorption and disposal of gases. For example, using GCMC simulations, some scientists have studied H2 uptake on charged SWCNTs. At temperatures 77 K and 298 K, they observed that charging of SWCNTs leads to a significantly better hydrogen storage than accessible in uncharged SWCNT systems. For positively charged CNTs, they observed a larger CO2 adsorption than in neutral samples, while the opposite has been detected for CNT systems with a negative charge. Negative charges lead to a weaker adsorption and to a reduced CO2/N2 selectivity than a neutral CNT bundle [7]. With the criterion of unloaded CNT samples, it is easy to understand that the absorption in a positively charged pregnant CNT is always greater than that in a negatively charged pregnant CNT. Compared with the neutral CNT mode, negative overloads increase adsorption in areas with low pressure and suppress adsorption in areas with high pressure, while positive overloads always increase adsorption [7].
