Synthesis Of Mesoporous TiO₂ And Its Application In Photocatalytic Degradation Of Organic Pollutants

Coal chemical wastewater contains a large amounts of organic pollutants,among which the content of phenolic pollutants is high,which is carcinogenic,teratogenic and mutagenic,and has a large impact on the environment and organisms if not treated properly.Therefore,effective treatment of organic pollutants in wastewater is the key to achieve reasonable treatment and green and sustainable development of coal chemical wastewater.Seeking efficient and low-cost wastewater treatment technology is an urgent problem in the field of water treatment today.The large forbidden band width of titanium dioxide(about 3.2 e V)and the fact that it can only utilize ultraviolet light but not fully utilize visible light greatly limit the industrial application of Ti O₂.The iodine-and potassium-co-doped mesoporous Ti O₂and the Bi₂O₃-Ti O₂ co-exposed with{001}crystal plane and{101}crystal plane prepared in this project have greatly improved the utilization of sunlight and significantly enhanced the photocatalytic activity.A combination of improved sol-gel method and surfactant evaporation self-assembly was used to prepare potassium and iodine co-doped mesoporous Ti O₂.compared with undoped pure Ti O₂,K-I-Ti O₂ has excellent photocatalytic activity and stability under simulated sunlight and good acid and base resistance.KI doping facilitates the formation of rutile phase,while the mixed system of anatase and rutile can improve the performance of photocatalytic degradation of 2,6-dimethylphenol.In addition,KI doping increased the specific surface area,pore volume and pore size of Ti O₂,which provided more active centers for the photocatalytic degradation reaction.This synthesis of mesoporous K-I-Ti O₂ catalysts provides a new idea for further design and development of more effective photocatalytic systems.Ti O₂ with co-exposed crystalline surfaces of{001}and{101}was prepared by an environmentally friendly hydrothermal method without hydrogen fluoride,and Bi₂O₃-Ti O₂ composite nanocatalysts were further prepared.The synthesized Bi₂O₃-Ti O₂nanocatalysts have high photocatalytic activity in visible light,and the degradation rate of 2,6-dimethylphenol can reach 98.3%in 180 min under visible light,and the catalysts also have good stability and acid-base resistance.visible region,reduced the band gap of the composites from 3.15 e V to 2.77 e V,and reduced the complexation rate of electron-hole pairs of Ti O₂ composites,thus effectively improving the photocatalytic performance of titanium dioxide.