Two recent studies report alternative strategies to the energy-intensive distillation process of petroleum refining. Instead of selectively boiling off crude oil components, the studies suggest membrane-based separation, but they differ in terms of the techniques used for separating the components with differing chemistries.
In one study, researchers use covalent organic framework (COF) membranes—crystalline porous polymers with pores whose size and chemistry can be tuned for selective filtration. These membranes separate aliphatic compounds (organic molecules with linear or branched chains) from aromatic ones (those with a ring-like structure) (Science 2026, DOI: 10.1126/science.aea0869).
“A simple way to think about it is as an ultra-thin molecular sorting layer [with] tiny, well-defined channels,” says Zhiping Lai, a chemistry professor at King Abdullah University of Science and Technology and one of the study’s authors. The membrane is treated with alkyl linkers to make aliphatic compounds interact more favorably with it and pass through the pores. Meanwhile, aromatic molecules are hindered because of their shape and the way they interact with the pores. The liquid passing through the membranes is rich in aliphatics—more than 95%—and the retained fraction is rich in aromatics.
The other study works with a type of material called polymers of intrinsic microporosity. Normally, these materials have subnanometer pores because of their rigid, contorted backbones. Study author Andrew Livingston, a chemical engineer at Queen Mary University of London, likens the material to packaged fusilli—with the twisted pasta-like shapes leaving a lot of gaps (Science 2026, DOI: 10.1126/science.aed1111).
But, Livingston explains, the pores can dilate and loosen in the presence of solvents. “To have control over the microporosity in the film, you need to somehow lock [the pores] in place,” he says. To do this, the researchers added a cross-linker that fixed the pore size. They call the product material polymers of locked intrinsic microporosity, or PLIM.
The PLIM membrane separates 99.8% of heavy hydrocarbons (with more than 15 carbon atoms), and 93% of sulfur-containing compounds. “In an ideal world, you could separate crude oil completely using membranes, [but] I think we’re a long way from achieving that,” Livingston says. His team is about to start working on using a cascade of membranes to get more than one fraction of material.
Lai and colleagues also see this work as a first step. “Just as conventional refining uses multiple separation steps, a membrane-based refinery would also likely use multiple tailored membranes to produce different product cuts with higher precision.” He continues, “Crude oil is an extremely complex feed, so long-term fouling resistance and membrane durability need to be studied further.”
Optimization in terms of crystallinity, pore orientation, and chemistry is needed to improve selectivity. “This work shows strong potential, [but] the next step is to translate that into pilot-scale demonstrations and eventually industrial integration,” he says.
Neetu Jha, a materials scientist at the Institute for Chemical Technology Mumbai who was not involved with either study, feels that the PLIM membranes will be more efficient than the ones based on COFs because the former are easier to scale up: “[PLIM fabrication] is completely based on chemical synthesis, whereas COF membrane fabrication [also] requires electric field application.”
She also feels that the membranes will be expensive to produce. Livingston agrees that it’s hard to estimate costs, but he also adds: “It will be dependent upon the ability to scale up and to optimize.”
