“Molecular Basket” Sorbents for Separation of CO₂ and H₂S from Various Gas Streams

TLDR

The study identifies a strong temperature dependence of MBS sorption for CO₂ and H₂S and proposes a novel approach that could significantly advance CO₂/H₂S capture from diverse gases. The authors aim to develop a laboratory‑scale sorption process to remove and recover CO₂ and H₂S from a model gas. The process employs MBS sorbents that combine nanoporous material with CO₂/H₂S‑philic polymer to increase accessible sorption sites. The new MBS sorbents achieve a CO₂ sorption capacity of 140 mg g⁻¹ at 15 kPa, outperforming existing sorbents, and enable CO₂ and H₂S separation from various gas streams.

Abstract

A new generation of "molecular basket" sorbents (MBS) has been developed by the optimum combination of the nanoporous material and CO2/H2S-philic polymer sorbent to increase the accessible sorption sites for CO2 capture from flue gas (Postdecarbonization), and for CO2 and H2S separation from the reduced gases, such as synthesis gas, reformate (Predecarbonization), natural gas, coal/biomass gasification gas, and biogas. The sorption capacity of 140 mg of CO2/g of sorb was achieved at 15 kPa CO2 partial pressure, which shows superior performance in comparison with other known sorbents. In addition, an exceptional dependence of MBS sorption performance on temperature for CO2 and H2S was found and discussed at a molecular level via the computational chemistry approach. On the basis of the fundamental understanding of MBS sorption characteristics, an innovative sorption process was proposed and demonstrated at the laboratory scale for removing and recovering CO2 and H2S, respectively, from a model gas. The present study provides a new approach for development of the novel CO2/H2S sorbents and may have a major impact on the advance of science and technology for CO2/H2S capture and separation from various gases.