Synthesis of Multivariate Indolo[3,2-b]carbazole-Based Zr-MOFs via In Situ Synthetic Modification for Propane Recovery from Simulated Natural Gas.

Adsorptive separation using metal-organic frameworks (MOFs) displays significant potential for propane (C3H8) recovery from natural gas, and the key lies in the synthesis of high-performance MOFs of proper pore environments. In this study, we employed an in situ synthetic modification strategy to successfully integrate chlorine (Cl) from metal salts into indole[3,2-b]carbazole-based organic ligands, thereby synthesizing a multivariate zirconium-based MOF (NUT-162) for C3H8 recovery from simulated natural gas. This material shows exceptional chemical stability across a broad pH spectrum (1.0-12.0) in aqueous environments. Featuring a high surface area and an ordered pore structure, NUT-162 demonstrates significantly higher adsorption capacities for C3H8 compared to ethane (C2H6) and methane (CH4) at 298 K. Grand Canonical Monte Carlo simulation suggests the zirconium clusters, aromatic benzene rings, and the ICZ motifs perform synergistically to achieve good selectivity. Dynamic breakthrough experiments further validate its outstanding separation performance in mixed-gas streams, and the performance can be well-maintained over multiple cycles. The material combines good durability and separation efficiency, offering a robust and practical solution for advancing the C3H8 recovery technologies.