A review on metal-organic frameworks as filler in mixed matrix membrane: Recent strategies to surpass upper bound for CO2 separation

[Display omitted] •Incorporation of MOF in polymer matrix enhanced the performance of MMM.•Modify MOF to surpass the upper bound limit.•Filler functionalization reduced the trade-off effect.•Geometry tuning and dual filler are other good strategies. Global CO2 emission continues to rise yearly and showing no sign of stopping, or at least, reducing. This worrying situation calls for a more environmentally friendly and cost-effective solution, on top of highly efficient technology. The polymeric membrane is a known method to separate CO2, but permeability and selectivity endure trade-off effects. Over the years, many works focus on suppressing this effect by dispersing fillers in the polymer matrix hence, producing a mixed matrix membrane (MMM). Despite the effort, the membrane trade-off effect is inevitable; thus, limits its application on a massive scale. Metal-organic frameworks (MOFs) is a contemporary brand of nanoporous material that has beneficial traits to be used as filler in MMM. This article will review a variety of MOFs types and their characteristics. Also, the MMM separation mechanism, together with its efficiency and the effects of operational conditions, will be the scope of this manuscript. Filler functionalization, geometry tuning, and dual filler are the strategies used to produce MMM that can surpass the upper bound. The performance of the filler-modified MMM was predicted using Maxwell and Bruggeman models. From this analysis, it was found that permeability and selectivity can be concurrently enhanced via the strategies mentioned; hence, avoiding the trade-off effect.