Removal of eutrophication agents from wastewater using glauconite-based sorbents

Abstract

Excessive phosphorus and nitrogen in water and sediment may cause eutrophication, which poses a potential risk to drinking water safety and the sustainability of aquatic ecosystems. The research focuses on the removal of phosphates and ammonium ions from aqueous solutions using a new thermally and microwave-treated glauconite. The surface morphology of the samples was studied by SEM. BET surface area, pore volume, and pore size distribution were measured. Adsorption studies were carried out in static and dynamic conditions. The best fit for adsorption of both pollutants is given by the Langmuir-Freundlich and BET models. The calcined sample showed the lowest adsorption capacity for phosphate (1.78 mg/g) but the highest capacity for ammonium (20.67 mg/g). For the microwave-irradiated sample, the adsorption capacity for ammonium increases from 0.723 to 4.37 mg/g, while that for phosphate remains almost at the same level (101.21 mg/g). In dynamic conditions, phosphorus was most efficiently retained by natural glauconite (more than 60% retention rate), and ammonium nitrogen by glauconite that was thermally treated in a muffle furnace (more than 80% retention rate after 3 h).