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

Abstract

High CO2 content exists in the raw syngas produced from supercritical water gasification of food waste, CO2 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 CO2 adsorbents. The adsorption experiments were conducted to investigate the optimal adsorbent and adsorption conditions. The results indicated that Mg2+ 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 CO2 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 CO2 adsorption capacity of Mg/Cu-BTC@MWCNT. The influences of different operating parameters on CO2 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: CO2 > CO > CH4 > H2. In additional, the regeneration experiment with 5 times was conducted and the result showed that Mg/Cu-BTC@MWCNT has high stability.