Environmental Sustainability Research Of Nano-TiO₂ Film Prepared By LPCVD

With researches about nanomaterials going deeper, application area of nanomaterials has been extended to all walks of life. However, there are always high energy consumption, low efficiency and pollution problems in nanomaterial production stage, which is contrary to the shortage of natural resources and human’s enhanced environmental awareness. Therefore, the demand for sustainability assessment of nanomaterials becomes increasingly urgent.LPCVD (Low Pressure Chemical Vapor Deposition) process for nano-TiO2 film is chosen as research object in this paper. Sustainability research of nano-TiO2 film has been present in three aspects:material and energy efficiency analysis, life cycle environment impact assessment, prediction for energy consumption and carbon emission during production.Firstly, fluid flow state in the LPCVD process for nano-TiO2 film was analysed based on fluid basic theory, and the motion equations in three temperature zones were established based on N-S Equations. Then the deposition rate function of nano-TiO2 film was obtained on the basis of Fick’s diffusion model. The precursor utilization efficiency and energy efficiency can be calculated by using laws of the conservation of mass and energy. The energy analysis result shows that the energy efficiency is extremely low (less than 0.1‰ in each condition) and the energy utilization efficiency is less than 0.1‰. The precursor utilization efficiency is highest on the condition (723K,500Pa) and the reaction condition (623K,500Pa) is regarded as a satisfactory condition with the highest energy efficiency.Secondly, based on the results of material and energy efficiency analysis, LCA method was chosen to study the life cycle environment impacts of nano-TiO2 film. This research was divided into two parts:on the one hand,0.1 mol nano-TiO2 film was chosen as the function unit, and the five environmental impact potential values (GWP, AP, EP, POCP, ET) were obtained by characterization, normalization and weighing of the life cycle inventory, the total environmental impact load is 0.024596 equivalent per person and the impact on global warming potential is most evident; On the other hand, by setting different LPCVD parameters, the impact of temperature and pressure on the evaluation result was studied. This study shows the environmental performances of nano-TiO2 film production stage are influenced by LPCVD process parameters, and the divergence indicator is 16.3%. Life cycle environment impact value is the lowest when the LPCVD parameter is (673K,500Pa).Finally, Scenario Analysis method was used to predict the future’s LPCVD process for nano-TiO2 film in baseline scenario, ideal scenario and conservative scenario. In this research, the energy consumption and carbon emission of China’s future nano-TiO2 film glasses production. The prediction of nano-TiO2 film glasses outputs is set up based on the outputs of plane glasses recently. The process energy efficiency optimization and China’s power structure evolution were considered to forecast the LPCVD carbon emissions. It can be concluded that even the volume of production and energy consumption are all increasing the trend of carbon emissions would have been falling because of the continuous optimization of grid’s structure.