Supported Geopolymer Adsorbents for Nutrient Removal from Urban Run-off Waters: Pilot Case Study

The new adsorbents consist of two layers and constitute a “core-shell” structure were developed and piloted in lab- and field scale. As a core layer, abundant and low-cost LECA was used, while the cover “shell” layer of geopolymers coating inert granules served as functional layer adsorbing pollutants. Two-layer structure allowed obtaining highly porous but light adsorbent granules, which may float in the near surface water layer. The approach substantially decreased a price of treatment technology due to less expenditure on functional materials on the one hand, and possible recycling potential on the other. Composite materials bind contaminants, preventing them from entering to the food chains or carrying them with hydrological flows, and repair of the natural circulation loops of elements. Since the adsorption materials were based on inorganic polymers constituting of a non-toxic aluminosilicate base, further potential applications of the material saturated with nutrients as promising slow-release fertilizers for forestry and agriculture were tested. Piloting of proposed materials in lab- and demo-scale on real matrices was carried out. The cost of adsorbents for water treatment was calculated, and cost-effective water treatment solutions based on supported adsorbents proposed.