Cu-BTC-based composite adsorbents for selective adsorption of CO2 from syngas

Abstract

• Successful modification of Cu-BTC with Mg 2+ and MWCNT . • CO 2 adsorption performances of Mg/Cu-BTC@MWCNT were evaluated. • High selectivity of CO 2 from syngas was achieved. High CO 2 content exists in the raw syngas produced from supercritical water gasification of food waste, CO 2 removal to improve quality of the syngas is necessary before further utilization. In this study, Cu-BTC, Mg/Cu-BTC, Cu-BTC@MWCNT, and Mg/Cu-BTC@MWCNT were synthesized and characterized as CO 2 adsorbents. The adsorption experiments were conducted to investigate the optimal adsorbent and adsorption conditions. The results indicated that Mg 2+ and multi-walled carbon nanotubes (MWCNT) doped into Cu-BTC influenced the physical properties of adsorbents. Among of all studied adsorbents, Mg/Cu-BTC@MWCNT had the maximum CO 2 adsorption capacity (3.63 mmol/g) and selectivity (14.28) at 25 °C and 100 kPa. Analysis of variance (ANOVA) exhibited that adsorption pressure had significant effects on CO 2 adsorption capacity of Mg/Cu-BTC@MWCNT. The influences of different operating parameters on CO 2 adsorption capacity and selectivity were discussed in Mg/Cu-BTC@MWCNT. The adsorption isotherms of gas components on Mg/Cu-BTC@MWCNT can be sorted as follows: CO 2 > CO > CH 4 > H 2 . In additional, the regeneration experiment with 5 times was conducted and the result showed that Mg/Cu-BTC@MWCNT has high stability.