Separation of CO2/CH4 Using Covalent Organic Polymer Adsorbent

Nowadays, natural gas is considered as one of the cleanest, safest gas and the most useful form of energy in our daily lives, its demand is increasing worldwide. One of the reasons the demand is still increasing is the presence of high amount of CO2 in natural gas. Removing bulk amount of CO2 from natural gas at high temperature, and low cost, it is still remaining as a major challenge for human beings. Different methods had been used such as membranes and others adsorbent such as zeolites but some of them are very expensive and limited. In 2012, Patel discovered an adsorbent called COP-1 which can capture CO2 better than others material. Patel’s COP-1 selectivity is 5616mg/g and it is stable at higher temperatures and higher pressures (200bars). Although COP-1 presents better characteristics patterns for CO2 capture, the material is still under studies and it is limited because Patel concentrated only in CO2/N2 separation. The main objective of this paper was to synthesize and characterize COP-1 under ambient conditions for CO2/CH4 separation. In order to achieve that objective, different techniques (FT-IR, TGA, BET surface area, pore size, and SEM) were used to verify that the synthesized material is COP-1. In overall, the characterization results show similarities to Patel Results (2012) in terms of functional group, linkage and absence of crystallinity with some differences such as the surface area. The surface area of this paper (11.944m2g-1) was lower compared to Patel area(168m2g-1). Using BELSORP pure gas adsorption of CH4 (0.1176mmol/g) and CO2 (0.6 mmol/g) were obtained. The selectivity obtained in this paper was 5.1g/g (CO2/CH4). Patel’s COP-1 is stable at 3600C in N2 environment and 2850C in air while the synthesized COP-1 was stable at 220 0C in both environments. Based on the results obtained, the synthesized COP-1 is useful for liquefied natural gas (LNG) industries because LNG stack temperature(1800C) is lower than 2200C. The objective was achieved.