PI E X M E I C O 2 0 0 7 Removal of Ammonium from Wastewater with the Mineral Vermiculite -Using PIGE for Nitrogen Monitoring

Abstract. Solid samples were irradiated with a 4.2 MeV proton beam in a specially built chamber. The ion beam was extracted out of the cyclotron vacuum system through a 4 ;m thick nickel foil. A helium gas flow of 10 cm 3 /min was used to avoid interference from atmospheric nitrogen and oxygen. The emitted gamma radiation was measured with an HPGe coaxial detector located behind the chamber. The reaction 14 N(p,p'@) 14 N was employed for the determination of nitrogen. The peak at 1454 keV from the nickel foil was used for the normalisation. A pressed pellet of KNO 3 was used for nitrogen calibration. The method was evaluated using six different biological certified reference materials. A synthetic tobelite mineral was also used in the evaluation. The limit of detection for nitrogen in the mineral samples was about 1 mg/g. The set-up was applied for the determination of the total amount of nitrogen in vermiculite. The mineral vermiculite was treated in different ways to optimize for the ammonium uptake. The experiments were performed by doping samples in ammonium solutions and by analysing the samples with PIGE. The aim of the study was to find a product that could be used for the removal of ammonium from wastewater