Impact of organic interlayer anions on the CO2 adsorption performance of Mg-Al layered double hydroxides derived mixed oxides

摘要

cqvip:Herein we report a systematical investigation on the promoting effect of the carbon chain length of the intercalated carboxylic anions on the CO_2 capture performance of Mg-Al layer double hydroxides(LDHs).A series of organo-LDHs were successfully synthesized via co-precipitation and calcination-rehydration methods. All as-prepared samples were characterized by many techniques including XRD, ATR-FTIR, BET,and TGA. The XRD and ATR-FTIR studies indicated that organic anions were successfully intercalated into LDHs. The influence of some important parameters such as calcination temperature, adsorption temperature, and coating with(Li-Na-K)NO_3 molten salt was investigated. The results exhibited that when the number of carbon is greater than 10, the CO_2 capture capacity steadily increased with the increase in carbon number. After coating with 55 mol%(Li-Na-K)NO_3 molten salt, the CO_2 uptake of LDH-C16 sample with high Mg/Al ratios can be increased up to 3.25 mmol/g. The CO_2 adsorption/desorption cycling stability was also studied using temperature swing adsorption, which showed a stable CO_2 capture performance even after 22 cycles. Considering its high CO_2 capture capacity and good cycling stability, this novel CO_2 adsorbent is very promising in the sorption-enhanced water gas shift(SEWGS) processes.