Filing activity in this space is concentrated: the top five assignees combined hold 133 of the 259 records in scope, or 51.4% of the field, and the single leading assignee alone accounts for 41 records. Beyond the top ten filers, who together hold 66.8% of records, ownership fragments quickly into a long tail of companies and individual inventors each contributing only a handful of filings. This means competitive monitoring should focus tightly on the leading names rather than trying to track the full 100-assignee ranking equally.

The trend is flat to declining rather than growing. Annual filings started at 12 in 2017, sat at a midpoint of 10 in 2022, then rose to a peak of 17 in 2024 before dropping in the most recent, still-incomplete year. Notably, none of the historically leading assignees show any filings in the latest tracked year, which — combined with the modest 2024 peak — suggests the core claim space around adsorbent composition and PSA process design may be reaching saturation, though the roughly 18-month publication lag means the newest year's data is always an undercount.

China is by far the dominant receiving office, with 127 of the tracked filings, more than three times the 37 filed in the United States. India (21), the European Patent Office (17), the WIPO/PCT route (15) and Canada (13) make up most of the remainder. Anyone doing freedom-to-operate analysis in this field needs to include Chinese filings directly, since a US- or EPO-only search would miss the majority of documented activity.

US20030171205A1, assigned to Zeochem, LLC and published in 2003, covers a process for producing molecular sieve adsorbent blends using a highly dispersed attapulgite fibre binder, with a specific tapped bulk density threshold (above roughly 550 g/ml measured to DIN/ISO 787) as a claimed process parameter. It is a process-and-material claim tied to that specific binder type and density specification, not a blanket claim over molecular sieve blending generally. Filings using different binder chemistries, or attapulgite fibre outside the claimed density range, would sit outside its direct scope, though a full claim-chart comparison is needed before relying on that distinction.

The IPC composition data shows the field is heavily concentrated in B01J (86.1% of records) and B01D (54.1%), meaning core adsorbent composition and separation-process claims are densely filed. Thinner coverage shows up where molecular sieve claims overlap adjacent applications — water and wastewater treatment (C02F, 3.9% of records), fuel purification (C10L, 3.9%) and condensation-polymer binder systems (C08G, 1.2%). These lower-density overlaps, along with specific process parameters like regeneration cycle control and attrition-resistant binder formulations, are the more promising areas to search before assuming the space is closed.