Abstract: Li⁺-doped nano-CNTS-TiO₂ composite photocatalyst (Li⁺/CNTS-TiO₂ composite photocatalyst) was prepared by sol-gel method using CNTS-TiO₂ as precursor. The sample was characterized by X-ray diffraction and Scanning electron microscope methods. The photocatalytic degradation of marine diesel was carried out using the 3% Li⁺/CNTS-TiO₂ composite photocatalyst. The effects of different factors, such as the amount of Li⁺ doping, calcination temperature, dosage of 3% Li⁺/CNTS-TiO₂ composite photocatalyst, initial diesel concentration, photocatalytic reaction time and H₂O₂ concentration were investigated under visible light conditions. According to the analysis of orthogonal test results, the optimum process conditions for degradation of marine diesel pollution with 3% Li⁺/CNTS-TiO₂ composite nano-photocatalyst were as follows: calcination temperature of 3% Li⁺/CNTS-TiO₂ composite nano-photocatalyst at 600 ℃, photocatalytic reaction time at 3 h, dosage of 3% Li⁺/CNTS-TiO₂ at 0.1 g/L, initial concentration of degraded diesel at 0.4 g/L, concentration of H₂O₂ at 0.6 g/L. Using these conditions, the degradation rate could reach more than 95%. At the same time, the photocatalyst was applied and tested. The test results showed that the photocatalyst degradation effect was excellent, and the degradation rate was up to 91.87%.

Key words: 3% Li⁺/CNTS-TiO₂ composite photocatalyst, nanometer, photocatalytic degradation, marine diesel pollution