The comparison of natural and magnetically modified zeolites as an adsorbent in methyl violet removal from aqueous solutions

Abstract

In this study, the use of clinoptilolite (natural zeolite) and Fe3O4 loaded clinoptilolite as adsorbents in the removal Methyl Violet from aqueous solutions were investigated and their adsorption capacities were compared. Primarily, the surface properties of the adsorbents were characterized by using spectroscopic techniques such as X-Ray Diffraction, Brunauer-Emmett-Teller, Scanning Electron Microscopy, and Fourier Transform Infrared Spectroscopy. Then, the effect of adsorption parameters such as initial pH value, adsorbent dosage, temperature, contact time, and initial concentration were investigated in order to optimize the adsorption parameters of these adsorbents. The experimental data indicated that the adsorption isotherms were well described by the Langmuir equilibrium isotherm model equation. The adsorption capacities of the clinoptilolite and the Fe3O4 loaded clinoptilolite were calculated as 135.13 and 153.85 mg g(-1), respectively. The adsorption of methyl violet was determined as compliance with the pseudo-second-order kinetic model. Thermodynamic calculations were made for both adsorbents. The calculated Delta H degrees values are 11.65 and 11.96 kJ mol(-1) for clinoptilolite and Fe3O4 loaded clinoptilolite, respectively, indicating that the adsorption process was spontaneous and endothermic. In addition, the adsorbent was reused seven times with the regenerated adsorbent technique and Fe3O4 loaded clinoptilolite was recovered by desorption. All experimental results show that the Fe3O4 loaded clinoptilolite was a natural, low cost and easily applicable adsorbent in the removal of methyl violet from an aqueous solution.