Use of faujasite-type zeolite for ion adsorption in municipal wastewater

In this work, a faujasite-type zeolite was synthesized from aluminum and silica gel using the sol-gel method. The zeolite was characterized using infrared spectroscopy (FTIR), x-ray diffraction (XRD), thernnogravinnetric analysis (TGA) and scanning electron microscopy (SEM). The synthesized material was identified as faujasite-type X. The capacity of the zeolite to remove organic matter, ammoniacal nitrogen, water hardness and heavy metals (Fe, Cu, Zn, and Pb) was evaluated. The removal capacity was studied in municipal wastewater and synthetic water. The sequence of effectiveness for the heavy metal removal by the faujasite-type X zeolite was Zn2+ > Cu2+ > Pb2+ > Fe3+ in municipal wastewater containing a high concentration of organic matter. Several factors affected ion removal, such as the concentration and type of the cationic species and the size of the hydrated cations in the adsorption process. The removal percentage obtained for heavy metal ions, water hardness and ammoniacal nitrogen was higher than 70%. A greater removal capacity for Ca2+ and Mg2+ (water hardness) and ammoniacal nitrogen was found. Therefore, the simplicity and the effectiveness of the synthesized zeolite made this a suitable alternative for treating municipal wastewater for ions, water hardness, and ammoniacal nitrogen removal. The results open the possibility for evaluating the implementation of adsorption columns on a large scale for municipal wastewater treatment.