Adsorption of Reactive Red 198 on Silicate Magnetic Nano Structure: Adsorption Studies and Modeling

In this study, a mesoporous silica nanostructure was synthesized and magnetized (Magnetic-SBA-15) and then its ability to remove reactive red 198 dye (RR198) from aqueous solution was investigated. The structure of produced adsorbent were evaluated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). the effect of effective parameters on the adsorption process such as pH, adsorbent dose, contact time, temperature and dye concentration were investigated and optimized. The optimum conditions for removal of reactive red 198 dye was pH =2, adsorbent dosage of 0. 4 g/l ,contact time of 60 minutes and temperature 25 ⁰C in 60 ppm of dye concentration. UV-vis spectrophotometer was used to determine the amount of residual dye in the solution. To determine the type of adsorption isotherm, the Langmuir, Freundlich and dubinin-radushkevich equations of adsorption isotherms were used. The results showed a good fit for the Langmuir adsorption isotherm (R2 = 0.997 and RL = 0.275). According to the values obtained from thermodynamic parameters such as enthalpy (-15.346 kJ/mol) and Gibbs free energy, the removal of reactive red 198 dye by Magnetic-SBA-15 was exothermic and spontaneous.