Enhancement Of Emulsifying Solubilization On Photocatalytic Degradation Of F113

In recent years,with the development of the fluorine industry,organic fluorine compounds have been increasingly used in various fields.However,many organic fluorides are biologically toxic and pose a serious threat to human health.Nevertheless,the organic fluorine compound has a large C-F bond energy,so the organic fluoride is extremely stable in nature.Therefore,it is of practical significance and application value for environmental protection and human health to study the treatment methods of organic fluorine compounds.In this study,trifluorotrifluoroethane（F113）is used to simulate the wastewater containing organic fluorine.The emulsifiers are sodium citrate and sodium pyrophosphate,irradiated with ultraviolet light with a wavelength of 185 nm,and photocatalyzed by UV and UV-TiO₂.The effects of emulsification of sodium citrate and sodium pyrophosphate in aqueous phase on photocatalytic dechlorination and defluorination of F113 are studied.Then the process parameters such as pH,temperature,amount of emulsifying salt and amount of catalyst are analyzed by orthogonal experiment.The optimal degradation conditions of F113are determined and the effects of different methods are compared.The main conclusions are as follows:（1）Sodium citrate emulsified UV method is used to degrade F113.The optimal reaction conditions obtained by orthogonal reaction are pH=7,temperature 40°C,and sodium citrate0.2g/200 mL.The degradation reaches equilibrium after 15h,the dechlorination rate reaches37.52%,and the defluorination rate reaches 9.19%.Sodium citrate emulsified UV-TiO₂ method is used to degrade F113,the optimal reaction conditions are pH=7,temperature 45°C,sodium citrate 0.4g/200mL,TiO₂ amount0.02g/200mL.The kinetic experiments show that the reaction equilibrium is reached after10h,the dechlorination rate reaches 41.86%,and the defluorination rate reaches 16.96%.（2）Sodium pyrophosphate emulsified UV method is used to degrade F113.The optimal reaction conditions for orthogonal reaction are pH=12,temperature 45°C,and sodium pyrophosphate dosage 0.35g/200 mL.Degradation reaches the reaction equilibrium after 9h,and the dechlorination rate can reach 20.04%,and the defluorination rate can reach 10.78%.The other conditions are unchanged.When the pH is adjusted to 12.5,the kinetic experiments show that the reaction equilibrium is reached after 9h,the dechlorination rate is71.06%,and the defluorination rate is 10.04%.Sodium pyrophosphate emulsified UV-TiO₂ method is used to degrade F113.The optimal reaction conditions for orthogonal reaction are pH=12.5,temperature 45°C,sodium pyrophosphate dosage 0.45g/200mL,and TiO₂ content is 0.03g/200mL.The kinetic experiments show that the reaction equilibrium is reached after 18h,the dechlorination rate reaches 95.50%,and the defluorination rate reaches 25.80%.The results show that the emulsifier sodium citrate and sodium pyrophosphate can promote the UV degradation of F113.Compared with the conventional UV-TiO₂ method,the defluorination rate of the degradation F113 reaction is increased from 3.86%to 11.94%.After the degradation reaction,the total defluorination rate is increased from 9.97%to16.96%,and the degradation time decreases from 24h to 10h.After adding sodium pyrophosphate,the defluorination rate of sodium pyrophosphate to UV-TiO2 system is increased from 3.86%to 13.78%,the total defluoridation rate is increased from 9.97%to25.79%,and the equilibrium time is shortened from the original 24h to 18h.It is significantly effective.The comparison results show that when the sodium citrate and sodium pyrophosphate are used alone,in the UV-catalyzed F113 defluorination and dechlorination degradation,sodium pyrophosphate is better than sodium citrate.Therefore,sodium pyrophosphate is the best emulsifier for photocatalytic degradation of F113,and sodium pyrophosphate emulsified UV-TiO₂ method is the best photocatalytic degradation method for F113.The optimal reaction conditions for orthogonal reaction are pH=12.5,temperature 45°C,sodium pyrophosphate dosage 0.45g/200mL,and TiO₂ content 0.03g/200mL.The kinetic experiments show that the reaction equilibrium is reached after 18h,the dechlorination rate reaches 95.50%,and the defluorination rate reaches 25.80%.