Adsorption of Compounds that Mimic Urban Stormwater Dissolved Organic Nitrogen

Abstract

Stormwater runoff carrying nitrogen can accelerate eutrophication. Bioretention facilities are among low impact development systems which are commonly used to manage urban stormwater quality and quantity. They are, however, not designed to remove dissolved organic nitrogen (DON) and may become a net DON exporter. Adsorption of seven organic nitrogenous compounds onto several adsorbents was examined. Batch adsorption study revealed that coal activated carbon (AC) exhibited the best performance in adsorption of the selected organic nitrogenous compounds. The highest adsorption capacity of coal AC was 0.4 mg N/g for pyrrole at an equilibrium concentration of 0.02 mg N/L, while adsorption was not detectable for urea at the same equilibrium concentration. The fastest compound to reach equilibrium adsorption capacity onto the coal AC was pyrrole (1 hour). The adsorption capacity of the coal AC for pyrrole and N-acetyl-d-glucosamine and 1-hour contact time is recommended for designing bioretention systems targeting organic nitrogenous compounds.

Activated carbon column adsorption of compounds that mimic urban stormwater dissolved organic nitrogen

“…Pyrrole was selected as a more hydrophobic, less labile, heterocyclic organic compound to provide a contrast to the other compounds. All of these compounds were also examined by the authors in their previous study on DON batch adsorption; more detailed information on the DON selection procedure, sources, and properties of these compounds can be found in Mohtadi et al (2017).…”

“…Glass columns were packed with a mixture of coal activated carbon (Calgon Carbon, Pittsburgh, Pennsylvania) and quartz sand (US Silica, Frederick, Maryland). According to the batch adsorption study by Mohtadi et al (2017), coal activated carbon (AC) and coconut‐shell AC demonstrated the best performance in DON adsorption among the tested adsorbents. Coal AC, however, possesses larger specific surface area and average pore size (798 m 2 /g and 53.3 Å) compared to coconut‐shell AC (547 m 2 /g and 30.6 Å, Mohtadi et al, 2017), indicating that coal AC would be a better choice for adsorption of large DON molecules.…”

“…According to the batch adsorption study by Mohtadi et al (2017), coal activated carbon (AC) and coconut‐shell AC demonstrated the best performance in DON adsorption among the tested adsorbents. Coal AC, however, possesses larger specific surface area and average pore size (798 m 2 /g and 53.3 Å) compared to coconut‐shell AC (547 m 2 /g and 30.6 Å, Mohtadi et al, 2017), indicating that coal AC would be a better choice for adsorption of large DON molecules. Higher particle density of coal AC (1,503 ± 19 g/L), compared to coconut‐shell AC (1,314 ± 65 g/L, Mohtadi et al, 2017), can also be a sign of stronger structure.…”

“…The batch adsorption of eight different organic nitrogenous compounds onto several adsorbents (coal activated carbon, coconut‐shell activated carbon, charcoal, peat, chitosan, water treatment residual (WTR), calcite, montmorillonite, zeolite and quartz sand) was studied by Mohtadi, James, and Davis (2017). For most of the examined adsorbates and adsorbents, either the adsorption capacity was negligible, or nitrogen leached from the adsorbents.…”

Synthesis of a novel Fe–Mn binary oxide‐modified lava adsorbent and its effect on ammonium removal from aqueous solutions

“…Nitrogen compounds are key components of animal and plant proteins, and essential element for all living organisms (Mohtadi, James, & Davis, ; Peierls, Caraco, Pace, & Cole, ). However, nitrogen pollution in hydrosphere has been pushed to unprecedented height for eutrophication of lakes and rivers all over the world (Ebeling, Timmons, & Bisogni, ; Kim & Novak, ).…”