Electrodialysis Membrane Patents: Leaders & White Space 2026
- Filing has plateaued, not grown. Activity peaked at 126 families in 2024 after climbing from 39 in 2017, but the 2022 midpoint of 76 shows the growth curve has already flattened.
- Claim density sits far outside water treatment. B01D separation processes cover 1,963 of 2,020 records, while C02F water/wastewater treatment trails at 713 — most of this art is filed as membrane or separation technology first.
- The US receives more filings than any single jurisdiction. 413 records route through the USPTO versus 295 in China and 279 at the EPO, with WIPO PCT filings (157) signalling deliberate multi-market strategies.
Filing growth compares 2021 (46 records) with 2024 (126) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 2,020 records in scope (CR5), not by the ranked leaders only.
What the electrodialysis membrane patent record shows
Electrodialysis membrane filtration patenting spans 2,020 families filed between 2017 and the 2026 data cut-off, concentrated overwhelmingly under separation-process classifications rather than water-treatment codes. The search string anchors on ion-exchange, bipolar and selective membrane language paired with electrodialysis or ED-stack terminology, so the corpus captures both classic desalination hardware and adjacent uses in electrolytic synthesis and fermentation recovery.
Filing activity rose steadily through the late 2010s, peaked in 2024, and has since eased — a pattern consistent with a technology that has moved from active claim-staking toward consolidation around established players. Because publication typically lags filing by around 18 months, the 2025 and 2026 counts in any trend chart understate real filing activity; treat the most recent one to two years as a floor, not a ceiling.
Filing trends and technology composition
Two views of the same 2,020-family corpus: how filing volume has moved year over year, and which IPC subclasses carry the claim weight.
A flattening curve after a 2024 peak
Filings grew from 39 in 2017 to a peak of 126 in 2024, but the 2022 midpoint of 76 sits closer to the peak than to the 2017 start, indicating the steepest growth is behind this field rather than ahead of it. Read the final one to two years as undercounted given publication lag, not as a genuine drop-off.
Separation process claims dominate the composition
B01D (separation processes) appears in 1,963 of 2,020 records — nearly the entire corpus — with C02F (water/wastewater treatment) a distant second at 713. C25B (electrolytic production), C07C (carbocyclic compounds), C08J (polymer processing) and C01D (alkali-metal compounds) each register in the low hundreds, showing electrodialysis membrane art is claimed primarily as separation hardware and only secondarily tied to a specific end-use industry.
Shares are the percentage of the 2,020 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Electrodialysis Membrane Filtration with Eureka
This page is one run against one query. Ask Eureka your own question about electrodialysis membrane filtration and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
Methods for producing or purifying onium hydroxides by means of electrodialysis
Methods of preparing or purifying onium hydroxides of the elements N, S or P by electrodialysis involve an electrodialysis apparatus comprising one or more cell units, each cell unit comprising a bipolar membrane and an anion-selective membrane, and a bipolar membrane or a cation-selective membrane being located on the anode side between the last anion-selective membrane and the anode.Filed by BASF Aktiengesellschaft; granted 2003-03-04.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6248469B1 | Composite solid polymer electrolyte membranes | 408 |
| 2 | US7550216B2 | Composite solid polymer electrolyte membranes | 366 |
| 3 | US6221225B1 | Apparatus and process for electrodialysis of salts | 196 |
| 4 | US4024043A | Single film, high performance bipolar membrane | 173 |
| 5 | US20020045085A1 | Composite solid polymer elecrolyte membranes | 162 |
| 6 | US5891328A | Membrane-frame for processes including electrodialysis | 133 |
| 7 | US20040055955A1 | Production of purified water and high value chemicals from salt water | 132 |
| 8 | US20110203929A1 | Recovery of lithium from aqueous solutions | 127 |
| 9 | JP2009269810A | Method for producing high-purity lithium hydroxide | 127 |
| 10 | US7083730B2 | Production of purified water and high value chemicals from salt water | 127 |
Citation counts favour older filings in any searched corpus — treat them as a measure of foundational influence, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for filing strategy
Three patterns stand out once the trend, geography and citation data are read together.
Growth has already crested
The rise from 39 filings in 2017 to a 2024 peak of 126, followed by a step down to 14 in the partial 2026 year, points to a field that expanded aggressively through the early 2020s and is now consolidating. New entrants filing broad, foundational claims face denser prior art than they would have five years ago.
Separation-process claims crowd out water-treatment framing
Nearly the entire corpus sits under B01D separation processes, while C02F water/wastewater treatment covers just over a third of records. Filers positioning membrane innovations as water-treatment solutions alone are competing in a smaller, more specific slice of the art than the separation-process framing implies.
The US remains the primary filing venue
United States filings (413) lead China (295) and the EPO (279), with 157 PCT filings suggesting a meaningful share of applicants are pursuing multi-jurisdiction protection rather than a single home-market strategy.
Co-filing is rare and concentrated
Only 10 co-assignee pairs appear across the corpus, with the strongest pairings clustering around a small number of corporate-group relationships rather than broad cross-industry partnerships. Most activity in this field is filed by single entities working independently.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to electrodialysis membrane filtration, with the prior art for and against each one.
Who is filing, and where activity has slowed
Assignee-level momentum reads differently from the aggregate trend: several historically active filers show no filings in the latest year, consistent with the broader plateau after 2024.
Several established filers have gone quiet
Assignees including Tokuyama Corporation, Solvay SA and Ionics, Incorporated show zero filings in the most recent year, and Evoqua Water Technologies LLC registers a full -100% year-over-year swing. Given publication lag, some of this reflects filings not yet published rather than a genuine stop.
Corporate-group co-filing outweighs cross-industry deals
The strongest co-assignee relationship in the dataset pairs two entities from the same corporate group, as does the second-strongest pairing between a chemicals firm and a national utility. Cross-industry joint filings exist but are the exception, not the norm.
Filing venue splits along familiar lines
The US leads on raw filing count, China and the EPO follow closely, and Japan (252) and Canada (104) round out a geographically dispersed field. No single office accounts for a majority of filings, which limits the value of a single-jurisdiction freedom-to-operate check.
| Assignee | Recent year | YoY |
|---|---|---|
| Tokuyama Corporation | 0 | — |
| Solvay SA | 0 | — |
| Ionics, Incorporated | 0 | — |
| Evoqua Water Technologies LLC | 0 | -100% |
| Archer-Daniels-Midland Company | 0 | — |
| AGC Chemicals | 0 | — |
| BASF Aktiengesellschaft | 0 | — |
| Research Institute of Industrial Science & Technology (RIST) | 0 | -100% |
Where to take this analysis
The aggregate picture points to a plateauing field with dense core claims and a few underexplored adjacencies. The next step is usually narrower than a full landscape.
Check freedom-to-operate on a specific membrane chemistry
The most-cited records concentrate around composite solid polymer electrolyte membranes and bipolar membrane construction — a targeted search against those claim families is a faster first check than re-running the full landscape.
Run a freedom-to-operate check in Eureka →Track assignees with zero recent filings
Several previously active filers show no activity in the latest year. Confirming whether that reflects publication lag, strategic exit, or a shift to trade-secret protection changes how much weight to put on their historical portfolio.
Monitor assignee activity in Eureka →Common questions about electrodialysis membrane patents
This dataset identifies 2,020 patent families published between 2017 and the 2026 data cut-off that combine electrodialysis or ED-stack terminology with ion-exchange, bipolar or selective membrane claim language. That figure covers a specific IPC-anchored search rather than every patent that mentions electrodialysis in passing, so broader keyword searches will return higher totals. Because publication lags filing by roughly 18 months, the true count for the most recent one to two years is understated in any trend view.
The assignee ranking is dominated by a mix of chemicals, water-treatment and industrial-materials companies, several of which — including Solvay SA and Evoqua Water Technologies LLC — show reduced or zero filing activity in the latest year. Co-filing is uncommon: only 10 co-assignee pairs appear across the corpus, and the strongest relationships sit within single corporate groups rather than across competitors. This suggests most innovation is still being protected independently rather than through joint ventures.
Filings rose from 39 in 2017 to a peak of 126 in 2024, then dropped to 14 in the partial 2026 year. The 2022 midpoint of 76 sits much closer to the peak than to the 2017 starting point, which means the steepest growth phase has already passed. Some of the apparent recent decline is a publication-lag artefact rather than a real slowdown, but the plateau after 2024 is a genuine signal that the field is consolidating rather than expanding.
The United States leads with 413 filings, followed by China at 295 and the European Patent Office at 279. Japan (252), WIPO PCT filings (157) and Canada (104) make up the remainder of the tracked receiving offices. The relatively even spread across major offices, combined with a meaningful PCT share, indicates that applicants in this space commonly pursue multi-jurisdiction protection rather than filing in a single home market.
The composition data shows claim density concentrated almost entirely in B01D separation-process classifications, with adjacent applications in fermentation recovery (C12P), alkali-metal compound purification (C01D) and polymer-solution processing (C08J) covered far more thinly. These lower-density subclasses represent areas where electrodialysis membrane techniques are being applied to a specific end-use but have not yet accumulated the dense prior art seen in the core separation-process filings. That makes them a more promising starting point for new claims than the crowded core.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.