Nitrate Removal from Drinking Water using Organo-Silane Modified Natural Nano-Zeolite

Nitrate-containing compounds are considered as groundwater contaminants, the concentration of which has been growing in these resources during recent years. As a result, it seems necessary to use effective methods to remove nitrate from water and wastewater. Adsorption is generally considered more economical in water treatment compared to other feasible alternative techniques. Natural Clinoptilolite zeolite is one of the best absorbents because of its high capacity and low cost. Surfactants such as hexadecyl trimethyl ammonium (HDTMA) are usually used for modification but they are not stable and removed as a result of subtle temperature variations. In this research, zeolite nanoparticles are chemically modified by 3-aminopropyl triethoxysilane. The advantage of this modification method is its stability at different environmental conditions. Adsorbent properties have been analyzed by PSA, FTIR, XRD, FESEM and CHN elemental analysis. Also, nitrate adsorption capacity of modified zeolite was examined by UV-Vis spectroscopy. NH2 groups are developed on the zeolite surface as a result of organo-silane modification, which must be converted to NH4 so that nitrate adsorption becomes possible in acidic conditions. Based on the results, the best nitrate removal capacity is achieved at the lowest concentration and pH values. 80.12 % nitrate removal was obtained at pH=3, nitrate concentration = 50 mg/l and adsorbent concentration = 4 g/l.