Removal of Heavy Metals Cd2+, Pb2+, and Ni2+ From Aqueous Solutions Using Synthesized Azide Cancrinite, Na8[AlSiO4]6(N3)2.4(H2O)4.6.

Aluminosilicate azide cancrinite, Na8[AlSiO4]6(N3)2.4(H2O)4.6, has been prepared for the first time from zeolite-A, followed by hydrothermal processing at low temperature. After crystallization, the sample was characterized by appropriate physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), thermal gravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) surface area. In the present study, attention was focused on investigating the removal performance of heavy metal ions (Cd2+, Pb2+, and Ni2+) in aqueous solution on pure aluminosilicate azide cancrinite. The kinetics of the process and sorption capacity of the adsorbent was determined in relation to the effect of various factors affecting on the adsorption process. The parameters in this study included contact time, metal ion concentration, temperature, and adsorbent dosage. The removal mechanism of metal ions followed adsorption and ion exchange process. Adsorption data has been interpreted in terms of Langmuir and Freundlich equations. The selectivity of the studied metal ions was determined as Pb2+ > Cd2+ > Ni2+. Thermodynamic parameters, i.e., equilibrium constant (Kc), free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) for adsorption, were computed from the experimental data. [ABSTRACT FROM AUTHOR]