Adsorption of Methylene Blue Dye from Aqueous Solutions onto Modified Nano-TiO2

In this research, initially modified nano-TiO2 was prepared from salicylic acid. Then, adsorption capacity of Methylene Blue (MB) onto modified nanoparticles was investigated in a batch system by considering the effects of various parameters like contact time, adsorbent dosage, pH, initial dye concentration and temperature. Optimum conditions for MB adsorption were found to be neutral and alkaline pHs, 0.4 g of adsorbent and equilibrium time≈ 50 min. The results showed that the increase of temperature and initial MB concentration leads to gradual decrease of adsorption rate. Evaluation of non-linear adsorption isotherm and kinetic models by Polymath software suggested that data can be well described by the pseudo-second-order kinetic and Freundlich isotherm models. Thermodynamic studies showed that the adsorption process was spontaneous and exothermic.