Seawater Reverse Osmosis Membrane Patents: Leaders & Trends 2026
- 47.4% of all 135 records sit with just five assignees, and 69.6% with ten — this is a concentrated field, not a fragmented one.
- Filing growth has cooled -18% from 2021 to 2024, the last year with complete published data, after a 2019 peak of 15 records.
- B01D separation-process claims cover 74.8% of records, while flotation and electrolytic routes barely register — a sign of where claim space is still thin.
Filing growth compares 2021 (11 records) with 2024 (9) — 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 135 records in scope (CR5), not by the ranked leaders only.
What the seawater RO membrane patent record shows
Seawater reverse osmosis membrane filings sit at the intersection of separation science and water treatment engineering: B01D (separation processes) and C02F (water and wastewater treatment) together dominate the classification profile, while smaller pockets of activity in polymer condensation chemistry, drilling-adjacent water handling, and electrolytic and flotation processes point to where the technology touches other industries. The corpus covers 135 records published between 2015 and the 2026-07-31 cut-off, drawn from filings that reference salt rejection, boron removal, chlorine tolerance, fouling propensity or membrane ageing alongside seawater RO or polyamide desalination membrane language.
Filing activity peaked in 2019 and has since eased, with the most recent complete year (2024) down 18% from 2021. Because publication typically lags filing by roughly 18 months, the 2025-2026 figures in the trend chart are still filling in and should not be read as a decline in actual filing behaviour.
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Filing trend and classification mix
Two views of the same 135-record corpus: filing activity over time, and where those records sit across the International Patent Classification system.
Filings rose to a 2019 peak, then eased
From a single record in 2017, filings built to a peak of 15 in 2019 before settling into a lower, steadier band. The 2021-to-2024 span shows an 18% pullback, the last comparison the data can support cleanly given publication lag on the most recent years.
Separation and water treatment classes dominate
B01D (separation processes) appears on 74.8% of the 135 records and C02F (water and wastewater treatment) on 51.9%, confirming that most filings are membrane- or process-centric rather than chemistry-centric. Smaller classes — C08G condensation polymers at 8.1%, C01D alkali-metal compounds at 3.7%, C07C and C25B each at 2.2%, and B03D flotation at 1.5% — mark adjacent, lightly claimed territory.
Shares are the percentage of the 135 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Seawater Reverse Osmosis Membranes with Eureka
This page is one run against one query. Ask Eureka your own question about seawater reverse osmosis membranes and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a recent filing
Nanostructured high-performance thin film composite reverse osmosis membranes and methods of manufacture (US20250360465A1)
The application describes a thin-film composite polyamide RO membrane with a 100-200 nanometre rejection layer over a 40-50 micron polysulfone substrate, cast on a nonwoven polyester backing. The distinguishing feature is incorporation of lignin and nanostructured silver-based metal-organic frameworks into the polyamide selective layer for hydrophilicity and antibacterial performance, built through interfacial polymerization of MPD-based aqueous monomer against the porous substrate.Filed by GREENVI CORP., published 2025-11-27 — one of the most recent records in scope.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | JP1980147106A | Osmotic membrane synthesized on interface | 147 |
| 2 | US20130213892A1 | Method and control devices for production of consistent water quality from membrane-based water treatment for… | 84 |
| 3 | US20070163951A1 | Chlorine resistant desalination membranes based on directly sulfonated poly(Arylene Ether Sulfone) copolymers | 74 |
| 4 | WO2011088505A1 | Low-fouling filtration membranes | 46 |
| 5 | US20060065598A1 | Method of treating reverse osmosis membranes for boron rejection enhancement | 43 |
| 6 | US20140151300A1 | Water treatment process for high salinity produced water | 41 |
| 7 | US7491334B2 | Method of treating reverse osmosis membranes for boron rejection enhancement | 39 |
| 8 | US7442309B2 | Methods for reducing boron concentration in high salinity liquid | 33 |
| 9 | US20150290595A1 | Modified thin film composite reverse osmosis membrane and a process for preparation thereof | 31 |
| 10 | US7806275B2 | Chlorine resistant polyamides and membranes made from the same | 26 |
Citation counts favour older records that have had more time to accumulate citations within the searched corpus; treat them as a signal of influence rather than current relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Concentration, classification mix and citation patterns each point to a different practical conclusion for someone deciding where to file or partner next.
The field is led by a small group, not fragmented
Five assignees hold 64 of the 135 records in scope and ten hold 94. That is a genuinely concentrated landscape: new entrants are filing into claim space that a handful of players have already staked out around core polyamide and thin-film composite chemistry.
Growth has cooled from its 2019 peak
Filings peaked at 15 in 2019 and the 2021-2024 comparison shows an 18% pullback. Read this as a maturing core rather than an active decline — recent-year momentum among named leaders shows zero new filings in the latest year across several previously active assignees, but 2025-2026 data is still incomplete.
Separation-process claims crowd the core
Three in four records touch B01D and over half touch C02F, meaning most competitive activity is happening in the same two classification buckets. The smaller classes — condensation polymers, alkali-metal compounds, flotation — carry far fewer records and represent comparatively open ground.
The most-cited prior art predates the current wave
The most-cited record in this corpus dates to 1980, with subsequent highly-cited work spanning chlorine-resistant sulfonated copolymer chemistry and boron-rejection treatment methods. These older records anchor freedom-to-operate analysis even where they are not the newest science.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to seawater reverse osmosis membranes, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders account for a large share of total volume, but the classification data shows several branches with only a handful of records — territory a new entrant could still claim cleanly.
A clear leader, then a steep drop
The top assignee holds 15 of the 135 records, with the fifth-ranked holder at 11 and the tenth-ranked at just 4. The gap between first and fifth place is narrow relative to the long tail below tenth, where single- and double-digit filers make up the bulk of the 64-company ranking.
Co-filing is limited and concentrated
Only ten co-assignee pairs appear in the corpus, and the strongest pairing recurs across a cluster of related filings while two other pairs share individual inventors rather than corporate partners. Collaboration is the exception here, not the norm.
Recent-year activity has gone quiet across leaders
Several of the most active historical filers show zero records in the latest year, including one with a -100% year-on-year change. Given the roughly 18-month publication lag, this likely reflects incomplete recent data rather than an actual stop in R&D activity.
| Assignee | Recent year | YoY |
|---|---|---|
| Hydranautics | 0 | — |
| Nitto Denko Corp | 0 | — |
| Water Standard Company MI | 0 | — |
| Council of Scientific & Industrial Research | 0 | — |
| S P TEXTILE PROCESSORS PVT LTD | 0 | — |
| BL Technology Inc | 0 | -100% |
| NLB WATER LLC | 0 | — |
| Yale University | 0 | -100% |
Turning this landscape into a filing or sourcing decision
A patent count is a starting point. The next steps depend on whether the goal is freedom-to-operate, partner scouting, or identifying where a new claim could actually stand.
Check freedom-to-operate against the concentrated core
With 69.6% of records held by ten assignees, any new filing in core polyamide TFC chemistry needs a claim chart against that group before development spend goes further.
Run a freedom-to-operate check in EurekaMap the under-claimed branches to a first claim
The smaller IPC classes — flotation, electrolytic integration, alkali-metal chemistry — carry few records each. Drafting a first claim there starts with reading what little prior art exists closely.
Explore white space in EurekaTrack the leaders whose filing has gone quiet
Several top assignees show zero filings in the latest year. Distinguishing a real pull-back from publication lag matters for competitive monitoring.
Set up assignee monitoring in EurekaCommon questions about seawater RO membrane patents
The ranking in this dataset covers 64 companies, with the top-ranked assignee holding 15 of the 135 records in scope. The top five assignees together account for 47.4% of all records and the top ten for 69.6%, which makes this a concentrated field rather than one spread evenly across many small filers. Anyone evaluating freedom-to-operate should start with that leading group before looking at the long tail below tenth place.
Filings peaked in 2019 at 15 records and the most recent complete comparison, 2021 to 2024, shows an 18% decline. That said, publication typically lags actual filing by around 18 months, so the 2025 and 2026 figures in any trend chart are still incomplete and should not be read as evidence of a continuing slowdown. The honest read is that the field has matured off its 2019 peak, not that innovation has stopped.
Most records classify under B01D, separation processes including filtration, which covers 74.8% of the 135 records, and C02F, water and wastewater treatment, at 51.9%. Smaller but present areas include condensation polymer chemistry (C08G), drilling-related water handling (E21B), alkali-metal compounds (C01D), and small pockets of electrolytic and flotation process claims. Because a single record can carry multiple IPC classes, these shares add up to more than 100%.
This 2025-published application from GREENVI CORP. describes a thin-film composite polyamide RO membrane with a nanoscale rejection layer incorporating lignin and silver-based metal-organic frameworks for hydrophilicity and antibacterial performance, built on a polysulfone substrate. It sits within the dominant B01D/C02F classification core rather than an open branch, so anyone developing MOF-modified or antibacterial polyamide selective layers should review its claim scope directly. As a 2025 filing it is too recent to have accumulated citation history, so its practical influence is not yet measurable from this corpus.
The classification data points to flotation-assisted fouling control, electrolytic pre-treatment integration, and alkali-metal scale-inhibition chemistry as the lightest-claimed branches, each represented in only a handful of the 135 records. These are not guaranteed to be commercially viable directions, but they carry noticeably less prior art density than the core polyamide TFC membrane claims that dominate B01D and C02F. A claim search focused specifically on those smaller IPC subclasses is the fastest way to confirm how open they really are.
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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.