The effect of temperature and pressure on nitrogen adsorption in amorphous silica

Nitrogen is an element that is widely found in nature can be used as a gas that is absorbed to help characterize materials, especially on the surface of the material. According to Brunauer - Emmet - Teller (BET) is a theory where nitrogen is used as a gas characterizing material because of its ability to high purity and can interact with solid elements and inert. BET can only produce quantitative data and does not show adsorption phenomena. Molecular dynamics simulation is conducted to observe the phenomena during nitrogen adsorption in amorphous silica, a porous material with a large surface area. In this study, the molecular dynamics simulations are arranged in a state of isotherm, where the temperature used is three variables: 77 K, 100 K, and 150 K in the variation of pressure used 1, 3, 5, 7, and 10 atm for each equilibrium. In molecular dynamics simulation to simulate the interaction between atoms based on Coulomb force is using Lennard-Jones Potential. Based on the simulation results obtain, it was found that at 77 K temperature had the optimal ability to adsorb nitrogen compared to 100 K and 150 K. The higher the pressure given in the system, it will increase the amount of nitrogen adsorbed.