Adsorption Separation of CO 2 /CH 4 from Landfill Gas by Ethanolamine-Modified Silica Gel

The utilization of landfill gas from municipal waste landfills has become a hot research topic. The separation and purification of carbon dioxide (CO 2 ) and methane (CH 4 ) from landfill gas has attracted widespread attention. In this study, ethanolamine (MEA), diethanolamine (DEA), and diethylenetriamine (DETA) were used to modify silica gel to improve the adsorption separation performance of silica gel for CO 2 /CH 4 . The results showed that the improvement in CO 2 /CH 4 separation performance by different organic amines followed the order of MEA > DEA > DETA. That is, the most effective modification was achieved by MEA. The adsorption of CO 2 onto MEA-modified silica gel was 84.83% higher than that on unmodified silica gel. The effect of MEA concentration on the adsorption separation of CO 2 /CH 4 was also studied. When the ratio of MEA to methanol was 1:6, the saturated CO 2 adsorption capacity of the modified silica gel reached 3.90 mmol/g, which was 84.83% higher than that of the unmodified silica gel. These conditions yielded the best CO 2 /CH 4 separation performance. The corresponding separation ratio was 8.51, which was 6.25% higher than that of the unmodified silica gel under the same conditions.