abstract
- © 2020 Elsevier LtdIn this research surface modified zeolites, Linde Type A and clinoptilolite, were used for the chromate ions uptake from aqueous solutions as well as its encapsulation through a vitrification process. The surface chemistry of zeolites was modified using a cationic surfactant hexadecyltrimethylammonium (HDTMA) to promote the capability of anions uptake. The results of characterization by X-ray diffraction showed unique crystalline phases for each zeolite which remain unchanged after the incorporation of the surfactant. Evidence from Fourier-transform infrared spectroscopy studies revealed the effective bond of the HDTMA on the clinoptilolite surface. Results suggested that the presence of CH2¿ groups after the modification play a key role for the anion attraction. Kinetic studies revealed that surfactant-modified clinoptilolite was able to adsorb 9.83 mg/g of chromate and better fitted pseudo-second order model (R2 = 0.957). The equilibrium was better represented by Freundlich model (R2 = 0.993). Finally, the proposed vitrification process the spent zeolitic adsorbent was successful, avoiding leaching of chromate ions after two months at different pH values.