Microplastic water filter

This invention

This invention is a drinking-water filter membrane with a sub-micron, asymmetric pore structure and an electrostatically functionalized surface. It captures nanoscale microplastic particles while keeping water flowing at the pressures and rates found in a typical home. The design pairs physical sieving with a surface-charge mechanism, so even particles smaller than the pores get caught. It belongs to the field of membrane separation and water-treatment technology.

Where it fits

Your idea sits squarely in Separation & Filtration (B01D), the dominant area in this result set (46 of 50 patents) and a tightly clustered corner — roughly 75× the corpus average. It overlaps strongly with Water Treatment (C02F), about 47× the baseline. That concentration is a healthy sign. It means membrane filtration for water is a real, actively pursued direction with decades of development behind it. Filings here run steadily from 2000 onward, including recent activity — an Entegris asymmetric-membrane patent published in 2025. Groups active in this area include Zenon Environmental, USF Filtration & Separations, Koslow Technologies, 3M Innovative Properties, Nitto Denko, and McMaster University. The field also connects to Nanotechnology (B82Y) and Magnetic & Electrostatic Separation (B03C), which these results touch more lightly.

Closest related work

US-12409423-B2 — Porous polyethylene filter membrane with asymmetric pore structure, and related filters and methods (Entegris Inc · 0 citations · 13-member family)

Filed in 2025, this very recent patent describes liquid-flowable porous polyethylene membranes with an asymmetric pore structure, plus filter components and methods of making and using them. It shows how Entegris approached the exact structural backbone you're working with — graded pore sizes through the membrane thickness to balance particle capture against flow. That makes it an excellent window into current thinking on asymmetric liquid-filtration membranes.

US-6045899-A — Highly asymmetric, hydrophilic, microfiltration membranes having large pore diameters (USF Filtration & Separations Group Inc · 232 citations · 14-member family)

This heavily cited, foundational patent covers highly asymmetric, hydrophilic microfiltration membranes, made hydrophilic by co-casting a sulfone polymer with a hydrophilic polymer. It shares your core goal: high surface porosity and good flow while maintaining separation. It shows how this group tackled the flow-versus-rejection trade-off through membrane chemistry and casting technique — a useful complement to your electrostatic-functionalization approach.

US-7462283-B2 — System and method for liquid filtration based on a neutral filter material (Entegris Inc · 7 citations · 15-member family)

This patent captures particles much smaller than the filter's pore size using surface-charge effects rather than pure sieving, with good flow and low pressure drop. That mechanism maps directly onto your electrostatic functionalization for catching nanoscale particles. It shows how surface-charge-driven capture has been framed and engineered, including the role of pH windows in tuning performance.

US-8696882-B2 — Nanoengineered field induced charge separation membranes and methods of manufacture thereof (Lawrence Livermore National Security LLC · 1 citation · 4-member family)

This describes porous membranes whose pore surface charge and configuration produce "double-layer overlap" effects, giving selectivity within the pores themselves. It's a close cousin to your electrostatic-functionalization concept, explored at the nanoscale. It shows how a research lab combined pore geometry with surface charge to achieve selective transport — useful background for the charge-based half of your design.

What you can do next

• Explore & build on it. Browse the related work above — new, differentiated ideas often come from combining or improving on existing approaches (a specific pore-gradient profile, surface-charge chemistry, microplastic-size selectivity, or residential flow-rate target others haven't pinned down).
• If you'd like to protect it. Filing a provisional application (usually with a patent attorney) is a common first step. Most inventions can be protected in some form — what matters is how broad and defensible that protection is, which is where a patent attorney adds value (a very narrow claim may be granted but protect very little).
• If you'd like to make or sell it. The patents above point to who