Removal of Aqueous Thiocyanate Anions by Titanium Dioxide Nanoparticles

Dissolved Thiocyanate in drinking water is a source of global health concern. The purpose of the present study was to remove aqueous Thiocyanate anions by using the titanium dioxide nanoparticles (TiO2 NPs). Titanium dioxide is inexpensive and non-toxic, making it an attractive choice for drinking water purification. Thiocyanate was adsorbed by the surface of nanoparticles into Fe-SCN complex and a filter was used for removing the nanoparticles. The effect of different parameters such as pH, buffer, time of stirring, the number of nanoparticles, concentration of the aqueous iron, and concentration of the electrolyte and its optimal amounts were investigated. Removal of the aqueous SCN- showed the best performance at the pH of 9, 0.5 mL of buffer, stirring for 15 min, and 0.5 g of TiO2. It was analyzed by means of spectrophotometry at ƛ=456.8 nm. Langmuir adsorption isotherm and Freundlich adsorption isotherm explained the best correlation between the Thiocyanate adsorption and equilibrium data. Langmuir adsorption isotherm showed more adaptability and the its sorption capacity was 11.6 mg/g-1 for nanoparticles. This method was tested for removing Thiocyanate from some real samples including tape water, Karoon River water, and water from petrochemical wastewater. Majority of the TiO2 NPs revealed an acceptable sorption capacity and reuse-ability in Thiocyanate anions removal in water solution.