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

Document Type: Research Paper

Authors

1 Shiraz University, Faculty of advanced technologies, nanochemical engineering department, shiraz, Iran

2 Faculty of Advanced Technologies, Nano Chemical Engineering Department, Shiraz University, Shiraz, Iran

Abstract

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. NH
2 groups are developed on the zeolite surface as a result of
organo-silane modification, which must be converted to NH
4+ 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.

Keywords