Adsorption of As (V) by poly (N-octyl-4-vinylpyridinium) bromide: Determination of As (V) by direct measurement of fluorescence on the solid phase

Abstract

Adsorption of As (V) by poly (N-octyl-4-vinylpyridinium) bromide (P4VPyC8), used as solid phase, was studied. Determination of As (V) was carried out by direct measurement of the fluorescence intensity on the solid phase. Adsorption variables were optimized for obtaining optimum values of pH and agitation time, where pH 9.0 and 60 min were established as optimum values. The adsorption of arsenic (V) was characterized by infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. It was found that the fluorescence of the solid phase increases as the concentration of arsenic increases. Linearity was observed in the concentration range 6.80 to 90.0 mu g L-1. The detection limit for determination of As (V) by this method was 2.24 mu g L-1 and the relative standard deviation (RSD) was 1.72%. The amount of retained As (V) was 0.154 mg/g of solid phase. The determination of As (V) in a sample of tap water by this method was well compared with the value reported by an external certified laboratory. Therefore, the method of analysis proposed here could be used as a screening methodology for monitoring the fulfillment of the norm for arsenic concentration in tap water.