Not all activated carbon is created equal
The retention of PFAS and pharmaceuticals highly depends on the pore structure, surface area, and contact time of the activated carbon used. Many commercially available filters use activated carbon that is too coarse-pored or in insufficient quantities, which means persistent molecules are hardly adsorbed. Studies show that only fine-grained activated carbon with a high microporous surface area (PAC or high-quality GAC) effectively binds PFAS and polar pharmaceuticals [US EPA, “Drinking Water Treatability Database – PFAS,”].
Why some filters achieve almost nothing
Many cheap filters only have a thin activated carbon film without sufficient mass or contact time. However, PFAS require long surface interaction to be adsorbed. Particularly short-chain PFAS like PFBA or PFBS pass through almost completely due to low bulk densities [Water Research Foundation, “Adsorption of PFAS by GAC,”]. Active pharmaceutical ingredients such as carbamazepine or diclofenac also require fine-pored structures, which are not present in simple pitcher filters.
Contact time is the decisive factor
Adsorption does not follow a "one-pass-and-done" logic. The so-called EBCT (Empty Bed Contact Time) is crucial. Professional systems achieve 2–4 minutes of contact time, while household pitchers sometimes only offer 2–5 seconds. Result: hardly any measurable reduction. Studies show that insufficient EBCT is the most common reason for poor PFAS retention values [NSF International, “PFAS Reduction Requirements,” ].
GAC vs. CTO vs. PAC – detailed performance differences
• GAC (granular activated carbon): high capacity, good for hydrophobic PFAS
• CTO blocks: dense structure, stronger for chlorine byproducts
• PAC (powdered activated carbon): highest surface area, ideal for micropollutants and pharmaceuticals
Filters without a combination of these structures can only insufficiently capture PFAS and medications.
Why SYDROS achieves significantly higher retention rates
SYDROS relies on highly porous activated carbon with a large specific surface area and optimized contact time, combined with additional adsorber stages for polar molecules. This enables the reduction of hydrophobic and hydrophilic PFAS as well as a wide range of pharmaceutical residues – areas where conventional pitcher filters or small cartridges clearly fail.
For real pollutant reduction, it's not about "just any activated carbon," but the right activated carbon – in the right amount and with the right contact time.
More information at sydros.de.
