Isothermal adsorption experiment of nitrate nitrogen in bioretention media

Abstract

Bioretentions can remarkably improve the rainwater quality. Though iron and aluminum as fillers in bioretentions can remove nitrate nitrogen, its adsorption mechanism is not clear yet and was rarely studied. This paper takes sand, iron powder and aluminum powder as the research objects to study the adsorption characteristics of nitrate nitrogen in the bioretention with different pH values and different ionic strength. The results show that aluminum powder has the highest the adsorption capacity. Langmuir adsorption isotherm equation and the quasi-secondary kinetic model are adopted to analyze the experimental data.