Removal of water nitrate using modified Purolite A520E resin, synthesis and experimental design

Abstract

Today, the amount of nitrate (NO3−) and nitrite(NO2−) anions as the last step in the oxidation of the nitrogen compounds are important chemical indicators of water pollution. The presence of nitrates in water causes illness. Removing these anions is costly due to the high solubility in the water. Numerous methods have been used to remove nitrates. Some problems with these methods include cost, low efficiency, interference of other ions, high power consumption, destroying electrodes, membrane obstruction and the need for an operator. However, using adsorbents is a convenient method to remove nitrate. In this study, the adsorption with the aid of the Purolite A520E resin, which is functionalized using magnetic iron oxide nanoparticles, is used to remove nitrate. In order to activate the resin, it was rinsed with acid and base and used as a powder with dimensions of less than 120 μm. Using experiment design, the optimum condition was obtained which was pH 6 and 60 min in the ambient temperature. To study the adsorption thermodynamics, the Langmuir and Freundlich adsorption isotherm was investigated. It was observed that the nitrate adsorption model of the resin had better agreement with the Langmuir model. The resin affinity for nitrate ion was compared with that of the other ions, It follows the pattern NO3− > SO4−2> cL−. Reuse of the recovered resin after 7 periods showed satisfactory results. FTIR, VSM, XRD, EDAX and SEM have been used to characterize the magnetic resin.