In situ casting of rice husk ash in metal organic frameworks induces enhanced CO₂ capture performance

Incorporation of rice-husk-ash (RHA), an agricultural waste, in situ during the synthesis of MIL-101(Cr) resulted in a significant improvement in the CO₂ adsorption properties over the synthesized RHA-MIL-101(Cr). The newly synthesized RHA-MIL-101(Cr) composite exhibited an enhancement of 14-27% in CO₂ adsorption capacity as compared to MIL-101(Cr) at 25 °C and 1 bar. The content of RHA incorporated in RHA-MIL-101(Cr) fine tuned the CO₂ capture performance to achieve high working capacity (0.54 mmol g^-1), high purity (78%), superior CO₂/N₂ selectivity (18) and low isosteric heat of adsorption (20-30 kJ mol^-1). The observed superior CO₂ adsorption performance of RHA-MIL-101(Cr) is attributed to the fine tuning of textural characteristics-enhancement of 12-27% in BET surface area, 12-33% in total pore volume and 18-30% in micropore volume-upon incorporation of RHA in MIL-101(Cr).