Adsorption characteristics of ammonium nitrogen in a bioretention system

Abstract

Ammonia nitrogen is one of the important pollutants in urban rainfall. Though iron ions and aluminum ions as a filler for plant retention system have a good effect on the removal of ammonia nitrogen, their adsorption characteristics was rarely studied. This paper uses different media (sand, iron powder, aluminum powder) with different pH values and ionic strengths in the Bioretention system to study the adsorption mechanism of ammonia nitrogen in an artificial rainwater. The result shows that Langmuir isothermal adsorption model is more in line with the ammonia nitrogen adsorption process, and the sand has the best adsorption capacity among three samples. Effect of pH values on adsorption kinetics is also studied.