Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 55 11 2024 01 21 Sulfate removal from water using TiO2 nanoparticles Sulfate removal from water using TiO2 nanoparticles 2311 2326 5260 10.22060/ceej.2023.22046.7888 FA Shahriar Mahdavi Malayer University Behnaz Taherinia Malayer University Amir Hossein Sayyahzadeh Malayer University Journal Article 2022 12 24 In this study, titanium dioxide nanoparticles were used for the removal of sulfate ions. The initial properties of the nanoparticles before and after sulfate adsorption were examined using instrumental techniques. The effects of parameters such as concentration, pH, time, and temperature on sulfate removal were measured, and the optimal conditions for each parameter were applied in the adsorption isotherm. The calculation of thermodynamic constants revealed a negative ΔG° (free energy of gypsum), indicating a spontaneous reaction that does not require energy input. The ΔH° (enthalpy) of the reaction was positive, suggesting an endothermic nature of the removal process, while the positive ΔS° (entropy) indicated an increase in disorder during the reaction. The Freundlich and Langmuir isotherm models were fitted to the experimental data under optimal conditions, with the Langmuir isotherm equation providing a better fit with an R² value of 0.994. EDX analysis confirmed that the titanium dioxide nanoparticles primarily consisted of titanium and oxygen before sulfate adsorption, while sulfur was observed after adsorption, indicating surface adsorption of sulfate. Furthermore, the maximum adsorption capacity of titanium dioxide nanoparticles for sulfate was calculated as 10.24 mg/g based on the Langmuir equation. By comparing this adsorbent with others, it can be concluded that these nanoparticles are effective in sulfate removal from water. In this study, titanium dioxide nanoparticles were used for the removal of sulfate ions. The initial properties of the nanoparticles before and after sulfate adsorption were examined using instrumental techniques. The effects of parameters such as concentration, pH, time, and temperature on sulfate removal were measured, and the optimal conditions for each parameter were applied in the adsorption isotherm. The calculation of thermodynamic constants revealed a negative ΔG° (free energy of gypsum), indicating a spontaneous reaction that does not require energy input. The ΔH° (enthalpy) of the reaction was positive, suggesting an endothermic nature of the removal process, while the positive ΔS° (entropy) indicated an increase in disorder during the reaction. The Freundlich and Langmuir isotherm models were fitted to the experimental data under optimal conditions, with the Langmuir isotherm equation providing a better fit with an R² value of 0.994. EDX analysis confirmed that the titanium dioxide nanoparticles primarily consisted of titanium and oxygen before sulfate adsorption, while sulfur was observed after adsorption, indicating surface adsorption of sulfate. Furthermore, the maximum adsorption capacity of titanium dioxide nanoparticles for sulfate was calculated as 10.24 mg/g based on the Langmuir equation. By comparing this adsorbent with others, it can be concluded that these nanoparticles are effective in sulfate removal from water. https://ceej.aut.ac.ir/article_5260_6018df1842f7130f1b85a6f8e911b96b.pdf