How Electropositive Filtration Works
This cartridge is the Argonide NanoCeram® P2.5-5 (2.5" x 5"), a pleated cartridge made by Argonide Corporation (Sanford, Florida). It is the standard non-AG version, with no silver. NanoCeram® media is a non-woven blend of microglass and cellulose fibers with nano-alumina fibers that carry a positive surface charge. Many fine particles in water carry a slight negative charge. As water passes through, the positively charged fibers attract and hold fine particles, while larger particles are captured mechanically.
- Rating: 0.2 micron (supplier rating), with an average pore size of about 2–3 microns
- Rated flow: up to 2.5 GPM (per supplier)
- Mechanism: charge attraction (electro-adhesion) plus mechanical capture
- Low pressure drop: the supplier reports flow comparable to conventional 1–2 micron pleated filters
- Sediment handling: high dirt-holding capacity (supplier figure: 82 g per square foot of media), so the cartridge copes well with cloudy water
- No power needed for the filter itself
- Best after prefiltration: upstream sediment and carbon stages reduce the load on the media and extend cartridge life
The NanoCeram media is certified by IAPMO R&T to NSF/ANSI 53 for material safety. This is a materials certification of the media, not a performance certification, and it does not certify the Purinade system. Independent lab testing of our system is planned.
Replacement: cartridge life depends on how much sediment is in your water. Replace when flow drops noticeably. Per the supplier, the terminal pressure drop is 35 psi.
Overview Electropositive Media
- Electropositive fibrous filter media with high particle removal efficiency and dirt holding capacity.
- In pleated form, flow rate matches or exceeds 1-2 micron rated filters, despite 0.2 micron nominal rating.
- Acts as a "broad spectrum" particle magnet, removing both coarse and fine particulates.
Comparison to Other Filters
- Most filters (membranes, fibrous depth filters) use sieving, inertial impaction, interception, and diffusion.
- Electropositive filters rely on adsorption (electro-adhesion).
- Unlike electropositive membranes, this filter avoids low dirt holding, quick fouling, low reliability, and high costs for materials, maintenance, and operation.
Benefits
- Enhanced Operations: Removes fines and coarse particulates, improving performance in various industries.
- Dirt Holding Capacity (DHC): High (supplier figure: 82 g per square foot of media).
- Fewer replacement elements.
- Lower maintenance costs.
- Less system downtime.
- Pressure Drop (ΔP): Lower than tight filters.
- Reduced energy use for fluid flow.
- Less wear on system components.
- Reduced Operational Costs: Avoids membrane-related expenses.
- No capital-intensive backflush systems or chemicals.
- No energy for backflush cycles.
- Minimal water waste.
- Lower labor for cleaning.
- No hazardous waste disposal from backflushing.
Technical Explanation
- Electroadhesion exploits charge differences via the double-layer effect in aqueous solutions.
- Most particles (especially smaller ones) are electronegative in water.
- Electropositive surfaces attract and retain particles more effectively than electronegative ones.
Advantages
- Uses nano alumina fibers with 350-500 m²/g surface area, mostly external and exposed to particulates.
- Surface area unattainable in membranes or standard fibrous filters (even with nanofibers, which are hard to produce below 100nm vs. 2nm for nano alumina).
- Prevents agglomeration (which reduces surface area) by grafting submicron alumina fibers to a scaffold, keeping them separate for optimal particle capture.
Applications and Material Certification
- Fine particulate filtration media for drinking-water pre-treatment and industrial process water.
- Material certification: The NanoCeram media is certified by IAPMO R&T to NSF/ANSI 53 for material safety. This is a materials certification of the media, not a performance certification, and it does not certify the Purinade system.
- Independent lab testing of Purinade® configurations is planned.