The search began with nearly 97,000 Scopus records matching terms associated with membranes and gas separation. Adding terms for permeability, permeance, and transport reduced the pool to approximately 38,500 documents. Excluding adjacent subjects such as membrane distillation, desalination, pervaporation, reverse osmosis, water purification, and filtration removed about 6,000 records.

Requiring terms such as biopolymer, biodegradable, or biobased then produced 914 documents, comparable to the 751 records retrieved for polymers of intrinsic microporosity, or PIMs. The query was not exhaustive: a 2001 paper on gas permeation in poly(lactic acid), for example, did not use “biopolymer” terminology. Adding terms for renewable resources and feedstocks captured that paper and 57 others.

Biopolymers are also studied as gas-barrier materials for food packaging, where the same transport measurements may be reported without being framed as membrane-separation research. Expanding the search to include packaging and “gas barrier,” and adding barrier to the transport terms, increased the final corpus to 2,909 documents, more than three times the original biopolymer-specific result. The author also notes that the database search is only an approximation of the field, so the figures describe the literature captured by the structured search rather than a complete census of every investigation involving a biopolymer membrane.

The volume of identified work has grown sharply since 1990. The cumulative count reached 1,193 documents by 2020, compared with 193 in 2010, and the corpus continued to expand through 2025. At that point, 70% of the documents were articles, 16% were reviews, and the remainder were book chapters and conference papers.

Only 34% of the full collection was open access, although the proportion was 45% for 2023, 36% for 2024, and 42% for 2025. The perspective argues that greater open access could reduce data gatekeeping and make transport measurements more available for comparison and synthesis. Polysaccharides were the most frequently mentioned material class, with 1,054 mentions among the articles classified for the analysis.

These included cellulose, chitosan, and starch, as well as lignin, lignocellulose, and algae-based materials. Cellulose, including nano- and microfibrillated cellulose, nanofibers, and nanocrystals, occupied the leading position within the class. Their biobased origin and general biodegradability are major attractions, but chemical modifications made to improve processability can substantially reduce biodegradability.

Cellulose acetate, a material commonly used in gas separations, illustrates that compromise. The figures are counts of article mentions rather than counts of distinct materials, because some articles were assigned to more than one category. Aliphatic polyesters generated 768 mentions and included poly(lactic acid), poly(butylene succinate), polyhydroxyalkanoates, and polycaprolactone.

All four are biodegradable, although poly(butylene succinate) and polycaprolactone) are generally not biobased. PLA is usually produced by biomass fermentation followed by chemical conversion from lactic acid to lactide and then polylactide, a route that limits its use as a single-use material in the European Union. Naturally occurring polyhydroxyalkanoates are generally produced by microbial fermentation, with their final chemical structure largely determined by the feedstock.

Other polymers fell into a group that could not be classified as polysaccharides or aliphatic polyesters. These included poly(vinyl alcohol), terephthalate- and furan-based aliphatic-aromatic copolyesters such as PBAT and PEF, polyethylene glycol, polynorbornenes, and polyurethane. Many have limited biodegradability but are biobased and are being investigated as potentially more sustainable alternatives to synthetic commodity polymers.

Biobased PEF, for example, is under investigation as an alternative to PET, while biodegradable PBAT is being studied as an alternative to LDPE. A final category comprised natural biomolecules such as gelatine, beeswax, silk, acacia gum, citrus pectin, and spirulina. These are generally used as additives with antioxidant, antibacterial, or other functions, and their effects on transport are often secondary to the original purpose of the investigation.

The distribution of measured penetrants reveals a pronounced mismatch with many separation applications. Water and oxygen dominate the literature because they are central to food packaging; both may also occur in flue gas, where water can act as a contaminant. Among the 2,031 articles examined, only 14% reported carbon dioxide permeability, 3% reported nitrogen permeability, and 2% reported methane permeability.

Helium, hydrogen, and hydrogen sulfide were also reported only in small numbers of papers. In the material-specific analysis, 71 articles reported nitrogen transport properties and 42 reported methane transport properties, making it difficult to evaluate many biopolymers for separations involving those gases. Some studies also addressed air, ethylene, ammonia, aroma barriers using limonene, organic vapors, and one propene–propane separation based on cellulose acetate.

Composite structures were prominent in the research record. More than 62% of the articles examined reported structural modification through the inclusion of particles or nanofibers, layering, or blending. Graphene was the most common filler, appearing in 97 articles, followed by ionic liquids in 35, metal-organic frameworks in 21, and zeolites in 17.

Combining materials can substantially change transport properties, but the perspective emphasizes that measurements for the pristine polymer should accompany results for each modification, including results that do not improve performance. The evidence base also contains limited modelling. Only 206 articles included modelling or simulation; 45 used molecular dynamics or density functional theory, and 20 examined process-level applicability.

More complete datasets would support structure–property relationships, material screening, and assessment under process conditions, although comparable operational data can be limited even for established membrane materials. Metadata analysis showed a global but fragmented research network. The 2,909 documents contained affiliations from 88 countries.

China led with 750 publications, followed by India with 400 and the United States with 279. Publications ranged from single-author papers to collaborations with as many as 19 authors from 10 countries, while almost half had three, four, or five authors. Only 221 documents, less than 8%, included at least one commercial industrial partner, with such partnerships recorded across 40 countries.

China accounted for 98 of the identified industrial collaborations. The count excluded engagement through public or private research and technology organizations, so it does not represent the full extent of participation by organizations that support translation and scale-up. The findings point to a possible research focus without establishing industrial readiness.

Many biopolymers are semicrystalline, which can restrict transport, and disrupting crystallinity or using reliable simulations may be necessary to characterize the behaviour of their amorphous phases. The author proposes that crystallinity could eventually be treated as a parameter adjusted for a particular application. Many biopolymers are also rubbery at or close to room temperature, and gas and vapor transport in rubbery polymers is driven mainly by solubility.

This creates a proposed opportunity for selective transport of highly condensable molecules, including volatile organic compounds, but the perspective stresses that the relevant transport properties still need to be measured. Consistent reporting of permeability, selectivity, unmodified controls, operating conditions, modelling, and process-level evaluation would help researchers identify which material–gas combinations are worth advancing and clarify where further work is required.

Subject of Research: Bibliometric analysis of biopolymer membranes for gas and vapor separation

Article Title: Biopolymers as membranes for gas separation: it is all about data

Article References: Papchenko, K. (2026). Biopolymers as membranes for gas separation: it is all about data. Frontiers in Membrane Science and Technology, 5, Article 2009069. https://doi.org/10.3389/frmst.2026.2009069

Image Credits: AI Generated

DOI: 10.3389/frmst.2026.2009069

Keywords: biopolymers, gas separation, membranes, gas permeability, literature analysis, industrial collaboration, composite membranes, modelling, research networks, sustainable materials, separation, data