Photocatalytic Degradation of COD and NH<sub>4</sub><sup>+</sup>-N Using TiO<sub>2</sub>/Sn<sup>4+</sup> Nanomaterials: Optimization of Physicochemical Parameters and Kinetics Studies

The photoactive nanocomposites TiO 2 /Sn 4+ with various ratios of Sn 4+ were prepared by a sol-gel method. Their morphology and crystal structure were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The effect of various parameters such as amount of doped Sn 4+ ions, catalyst loading, initial pollutant concentration, pH value, H 2 O 2 concentration on photocatalytic degradation performance were analyzed and optimized. The optimal experimental conditions obtained through orthogonal experiments that highest value was obtained at 3%-Sn 4+ doping amount, catalyst dosage 1.5 g/L, initial chemical oxygen demand(COD) concentration 600 mg/L, initial ammonia nitrogen(NH 4 + -N) concentration 50 mg/L, H 2 O 2 3%, and pH = 8. The photocatalytic degradation rates of NH 4 + -N and COD reached 87.54% and 75.32%, respectively.