The Nano Tio <sub> 2 </ Sub> Photocatalytic Oxidation Treatment Ammonia Wastewater Study

It is treated the wastewater of NH₃-N by TiO₂ photocatalytic oxidation. The purpose lies in researching the result and the effective factors on the treatment. The TiO₂ photocatalytic oxidation is a method of the advanced oxidation process which has been adopted more and more in wastewater treatment. TiO₂ nanoparticles is a new material ,a better photo-catalyst than normal particle TiO₂. The paper combines them and studies the impossible of the treatment of the wastewater of NH₃-N by using them and researches the effective factors in the process.The TiO₂ film is deposited on the surface of glass with Na₂SiO₃ as binder by the particle-roasted. The influence of conditions in immobilization on the catalyst is studied by its photo degradation of the wastewater of NH₃-N . In the experiment the Ag⁺ was added in the wastewater and the Ag is deposited on the surface of catalyst. The result of the experiment shows: (1)When the proportion of TiO₂ to Na₂SiO₃ reaches 1.5 and the roasted temperature reaches 290 ℃ , the catalyst has the highest activity ,and the degradation percent of NH₃-N is 74.1% and 77.5%. (2)When adds Ag⁺ to the wastewater, the degradation rate of NH₃-N will increase with the volume of the Ag⁺ increasing. However the degradation rate will keep fixture. when the added Ag⁺ reaches 1.0g/L, in this time, the degradation percent of NH₃-N is 82.6% But the removal percentage of NH₃-N doesn't increase simply with the increase of Ag when we add Ag to the surface of TiO₂. There is a best proportion: the photocatalytic activity increases first and decreases last with Ag increasing. When Ag is 10%, the photocatalytic activity is the best, and the degradation percent of NH₃-N is 81.4%.The paper studies four influent factors, the treatmenttemperature, pH, the air. rate and the quantity of catalyst, by its photo degradation of the wastewater of NH₃-N. The result of the experiment shows: (1)The photocatalytic oxidation is a good method for degradation of the wastewater of NH₃-N. The adequate reaction conditions are found as following: the temperature is 30°C, the air rat is 0.26m³/h, the pH is 8.2, the quantity of catalyst reaches 2.0g/L. (2) The orthogonal test is carried out with four greater factors effected on the treatment. The four factors are the treatment temperature, pH, the air rat and the quantity of catalyst. The experiment defines the influence turn of each factor is : the quantity of catalyst > the air rate > pH > the treatment temperature.The paper involves the contrasted degradation of NH₃-N by using TiO₂ nanoparticles and normal particle TiO₂ as catalyst. The result shows that the degradation ratio by using TiO₂ nanoparticles is better than normal particle TiO₂. The treatment temperature, the air rate ,pH and the quantity of catalyst affect them similarly.The dynamics of photocatalytic oxidation with the supported film TiO₂ fitted the model of L-H, it's dynamic character shows that it appeared zero-grade reaction under high concentrations and one-grade reaction under low concentrations.