Marziyeh Ranjbar-Mohammadi

The aim of this study was to statistically evaluate the capability of a prepared TiO2/gum tragacanth hydrogel as a photocatalystfor the removal of methylene blue dye molecules from contaminated solutions. In this regard, TiO2nanoparticles were sonicatedin gum tragacanth and the final hydrogel was prepared by the addition of glutaraldehyde as a crosslinking agent. Responsesurface methodology was employed as a mathematical and statistical tool to describe the system by a polynomial equationthat relates the removal efficiency to selected variables (time, pH, initial dye concentration and photocatalyst dosage). Thesignificance and adequacy of the model were confirmed by high coefficient of determination (R2) and adjustedR2values (>93%).Thesystemwasoptimizedataninitialdyeconcentrationof9.37 mg L−1,pHof9.02,timeof124.34 minandphotocatalystdosageof 0.13 g L−1using the response optimizer with an efficiency of 88.86%. A kinetic study of photocatalytic decoloration indicatedthat the pseudo-second-order model was well fitted to the experimental data.