Recovery of Polluted Urban Stormwater Containing Heavy Metals: Laboratory-Based Experiments with Arlita and Filtralite

Heavy-metal sources in urban environments include automobile exhaust, fuel combustion, tires, road asphalt, weathering of building materials, and/or industrial activities. The presence heavy metals stormwaters constitutes a potential risk for water resources and aquatic life. Results from the present study demonstrated effectiveness two different lightweight aggregates (LWAs), Arlita Filtralite, to remove (Ni, Cu, Zn, Cd, Pb) aqueous solutions. These materials were selected because they previously showed great results treatment their physicochemical properties. removal efficiency studied was evaluated with batch tests containing solutions contaminated (with individual multiple contaminants) at concentrations mixed LWA particles. Filtralite better performance metal than Arlita: higher adsorption capacity all metals, lower release particles into washing water. average capacities developed contaminants 76% 90%, respectively, although values varied across contaminants. Metal elimination by LWAs more effective multielemental ones. analysis curves, mineral precipitation on surface, geochemical modeling confirmed that mechanisms are responsible heavy-metal removal. First, rough surface presents sorbing sites forming minerals, resulting ion-exchange reactions ions. Second, LWA–water interaction causes an increase solution pH, which triggers coprecipitation form oxide hydroxides. confirms use especially promising stormwaters.