Hydrothermal synthesis of high surface area mesoporous silica as an efficient adsorbent for removal of crystal violet dye from aqueous solution

In this work, a sample of mesoporous silica (MPS) with a high surface area was prepared by hydrothermal synthesis procedure. To investigate the properties of the prepared sample, it was characterized using different techniques like N2 Adsorption-desorption, Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Atomic Force microscopy (AFM). In order to evaluate the efficiency of the prepared MPS, adsorption study was carried to examine the ability of MPS to remove crystal violet dye (CV) from aqueous solution. The study was done in different conditions of initial concentration (25-60 mg/L) of dye, dosage of MPS (0.01-0.05 g) and temperature range (293-323K). The results were applied to three adsorption isotherms which are, Langmuir, Freundlich and Temkin models and gave a very high match with Freundlich equation (R2 = 0.9678). The kinetics of adsorption study was also applied using first order and second order kinetics model in addition to intra particle diffusion model. It reveals that removals of CV dye by MPS is a second order reaction and diffusion step is not the only limiting steps as the linear equation of intraparticle diffusion did not pass through origin. Thermodynamic investigation reveals spontaneous behavior and endothermic nature of adsorption process.