Functionalized polymer adsorbent for nitrogen and phosphorus removal in stormwater runoff

Overview

Stormwater runoff passing through bioretention systems often carries elevated levels of nitrogen species, particularly nitrate (NO3-) and dissolved organic nitrogen (DON), which can degrade downstream water quality. This solution introduces functionalized polymers with ultrahigh surface area as advanced adsorbents specifically engineered to capture these nitrogen species while also capturing phosphorus. By tailoring the internal pore environment through carefully selected functional groups, the polymers can be tuned for hydrophilicity, charge, and pore size to maximize binding affinity for targeted contaminants.

The technology addresses a critical need in urban stormwater management, where conventional bioretention cells frequently discharge nitrogen-enriched effluent. The dual capability to remove both nitrogen and phosphorus makes this approach attractive for municipalities, water utilities, and environmental engineering firms seeking cost-effective treatment upgrades.

Technical specifications

Key features:

• Ultrahigh surface area architecture reaching up to 4000 m2/g, enabling high-density incorporation of adsorption sites
• Customizable functional groups that tailor internal pore environment for hydrophilicity, surface charge, and pore size
• Selective targeting of nitrate (NO3-) and dissolved organic nitrogen (DON), the dominant nitrogen species in bioretention discharge
• Simultaneous phosphorus capture as a secondary benefit
• Structure-property relationships refined through iterative testing to guide upgraded polymer designs
• Compatibility with existing bioretention infrastructure for straightforward integration

How it works:

The polymer's exceptionally high surface area provides extensive contact zones for contaminant binding. Functional groups introduced during synthesis modify the internal pore characteristics, creating chemical environments that preferentially attract and retain the targeted nitrogen species. Phosphorus ions are captured through the same adsorption mechanism during the treatment process.

Technology readiness level

The technology is currently at an early-to-mid development stage. Synthesis and characterization of an initial series of functionalized polymers are planned within the first two months, followed by performance assays for nitrogen removal and phosphorus capture in month three. Structure-property relationships will be refined in months four and five to guide an upgraded polymer version. A pilot-scale prototype will then be developed and field-tested in collaboration with Oldcastle during months six through nine, representing a critical step toward real-world validation and commercial readiness.