Synthesis and Application of Titanium Dioxide Nanoparticles for Removal of Cadmium from Wastewater: Kinetic and Equilibrium Study

Cadmium (Cd) contamination in water resources has become a potentially serious threat to public health and environment across the globe. In this experiment, we investigated the capacity of titanium dioxide nanoparticles (TiO 2 NPs) for selective removal of Cd from wastewater. The TiO 2 NPs were prepared using newly developed sol-gel method and sorption attributes were investigated as a function of contact time, sorbent dosage, pH, and initial Cd concentration. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were successfully employed to delineate the Cd sorption equilibrium results. The Langmuir isotherm and pseudo-second-order kinetic models well fitted the experimental data compared to all other models showing that the Cd sorption was attributed to monolayer sorption and chemisorption process, respectively. The maximum Cd sorption was observed as 89.45% at pH 4.3 with 0.7 g L −1 , 30 mg L −1 initial Cd concentration, and 2-h shaking time duration. The SEM analyses revealed that the surface of TiO 2 NPs was extremely loaded with the cluster of rough and smooth sites in round form which favored the Cd sorption from solution. Thus, TiO 2 NPs could be promising, low cost, and eco-friendly sorbents for Cd adsorption from wastewater.