Chemical immobilization of amino acids into robust metal-organic framework for efficient SO2 removal

Adsorptive removal of trace SO2 emissions from flue-gases can significantly reduce energy and water consumption and minimize the amount of unmanageable waste, however, this remains a great challenge. Herein, we report a universal strategy of chemical immobilization of amino acids into a robust metal-organic framework to enhance deep desulfurization. The grafted amino acid resulted in the formation of pores with compatible pore sizes and created abundant N-containing moieties for selective SO2 adsorption. MOF-808-His (His = l-histidine) exhibited a top-ranking SO2 uptake (10.4 mmol g(-1)) with an excellent SO2/CO2 selectivity (90.5) under ambient conditions; furthermore, MOF-808-His could be easily regenerated. Breakthrough curves verified its excellent separation performances with water vapor and real flue-gas compositions. Computational simulations confirmed the vital role of immobilized amino acids in improving the SO2 capture ability and selectivity. As a proof-of-concept, five natural amino acids were immobilized into MOF-808; all samples displayed improved adsorptive desulfurization performances.

Automated summary

The study presents a universal strategy for enhancing deep desulfurization by chemically immobilizing amino acids into a robust metal-organic framework. The modified MOF-808-His material exhibited excellent adsorption performance with high SO2 uptake and superior SO2/CO2 selectivity. The findings highlight the crucial role of immobilized amino acids in improving SO2 capture ability and selectivity.