Phosphorus removal from water using fly ash and modificated fly ash - comparison of X-Ray fluorescence spectrometry and standard spectrophotometric methods

Abstract

This study investigates sorptive properties of three different types of fly ash and one fly ash type treated with a 1M, 3M, and 6M solution of NaOH to remove phosphates from water. In addition, this work examines possibilities of using the Wavelength Dispersive X-ray Fluorescence (WD XRF) spectrometry method for the analysis of phosphorus in liquid samples. The WD XRF method was compared with the standard spectrophotometric method (molybdate method). The results showed that the fly ash containing the highest initial CaO concentration sorbed the greatest amount of phosphorus. The treatment of fly ash with NaOH solutions did not significantly enhanced the sorption capacity of fly ash. The determination of P in fly ash indicated a good correlation between both methods, thus validated the application of XRF for the analysis of P in water.