Key facts
- The bare PAN membrane needs no selective surface coating, which the researchers said makes it cheaper and less prone to defects at scale.
- Heavy hydrocarbons stuck to the pore walls and narrowed the pores to separation channels smaller than 2 nanometers, per the study.
- Process simulations in the study estimated a 31.6% cut in energy use and a 37.6% cut in carbon dioxide emissions as a pretreatment step.
- The researchers said refineries could adopt the technology through simple retrofits with a modular filtration unit and no large investment.
- The membrane cannot replace distillation proper but can separate fractions before crude oil is heated above 350 °C (662 F), the researchers said.
- The scientists said the membrane could also be applied to petrochemicals and waste plastics recycling separation processes.
Researchers from the Korea Advanced Institute of Science and Technology and the Georgia Institute of Technology reported a method for separating crude oil fractions with a bare porous polyacrylonitrile membrane, a chemically stable and inexpensive polymer commonly used as a support material in industrial membranes. The study was published in Nature this year, according to the report dated November 9, 2026.
Earlier membrane work assumed a selective layer had to be coated onto the surface to separate molecules, but such additional-layer membranes are expensive to make and potentially defective when produced at scale. The researchers instead passed crude oil directly through the uncoated membrane at room temperature. Heavy hydrocarbons selectively stuck to the pore walls, gradually narrowing the pores and creating separation channels smaller than 2 nanometers, according to the study.
The study reported that the bare membrane delivered crude oil permeation rates approximately 23 times higher than those of previously reported state-of-the-art crude oil membranes while maintaining stable performance for 28 consecutive days. Ryan Lively, a professor at Georgia Tech, said the separation mechanism "dramatically increase the productivity of the membrane unit, to the point where industry should seriously consider adopting the technology."
The researchers said refineries could adopt the technology through simple retrofits by adding a modular filtration unit that would not require large investments. The membranes cannot replace distillation proper, but can be used at an early stage to separate fractions without heating crude oil above 350 °C (662 F) from the start, avoiding part of the energy use and emissions of refining.
Process simulations in the study showed that using the membrane as a pretreatment step before conventional distillation could reduce energy consumption by 31.6%, carbon dioxide emissions by 37.6%, cooling water usage by 20.7% and operating costs by 36%. The scientists said the membrane could also be applied to other chemical separation processes in the petrochemicals and waste plastics recycling industries.
Jihoon Choi and Hyeokjun Seo of KAIST, the study's co-first authors, said their goal is to control the pore-constriction effect and develop it into a membrane platform for the entire refining process, and to expand the technology to plastic recycling, biofuel purification and other chemical processes.
The report noted that MIT engineers said last year they had developed a crude oil fractionation membrane, described in the journal Science, that could cut the energy needed to process crude into fuels by as much as 90%. Zachary P. Smith, an associate professor of chemical engineering at MIT and senior author of that study, said the filters can separate very small molecules at an atomistic length scale.