Synthesis and characterization of zeolite X from granite stone sludge

Zeolites are one of the most widely used materials for environmental pollution control and remediation. In the present study, the granite stone sludge (GSS) was used as a precursor for the synthesis of X-type zeolite through alkali fusion followed by hydrothermal treatment. Samples were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Scanning electron microscopy analysis/ energy-dispersive X-ray spectroscopy (SEM/EDX), Fourier transform infrared reflection (FT-IR) and surface area (BET). The pre-acid treatment of the GSS reduced the Fe content and, consequently improved the yield and quality of the produced zeolite. The effect of various parameters including the aging time, fusion temperature, residence time, GSS to NaOH ratio, and crystallization time on the zeolite synthesis were investigated. The surface area of GSS and synthetic zeolite X were 4 and 75 m 2 g −1 , respectively. The low silica zeolite X with about 100 % purity and Si/Al ratio of 1.3, was obtained under conditions of aging time of 24 h, calcination temperature of 400 °C, GSS/NaOH 1:1.2, residence time of 1 h, and crystallization time of 6 h. The efficiency of the synthesized zeolite for the removal of cadmium from aqueous solution was approved.