Design Of Equipment For Advanced Oxidation Assisted By Ultrasound And Technical Study On Treatment Of Dye Intermediate Wastewater

This project designed the dual-low frequency ultrasonic synergistic ozone device,and used the dual-low frequency ultrasonic synergistic ozone system to treat the H acid simulated wastewater and the actual wastewater and optimize the operating parameters.The removal effect of COD under optimal operating conditions was investigated,and the degradation mechanism and path were explored.The changes in the types and contents of organic matter before and after treatment by GC-MS test and comprehensive analysis were carried out.Firstly,according to the knowledge of acoustics,the dual-low frequency ultrasonic synergistic ozone reaction device was designed.The two frequencies of 40 kHz and 28 kHz were selected(the maximum working power was 300 W at each frequency),and the transducers were installed on opposite sides and arranged at intervals.The iodine release method was used to study the acoustic cavitation yield,and it was concluded that the dual-low frequency ultrasound has a cavitation enhancement effect and can improve the COD removal rate.Comparing different treatment methods,it shows that under the same ozone dosage,the COD removal rate after double-low frequency synergistic ozone can be increased by 10%compared with ozone alone,but the increase is not large but the ozone utilization rate can be improved.The double-low frequency ultrasonic irradiation is used for ozone oxidation.Have a synergistic effect.Then,the napHthalene dye intermediate H acid monosodium salt was selected to prepare simulated wastewater.The degradation effect of the double-low frequency ultrasonic synergistic ozone system on H acid was studied.The optimum operating conditions were obtained to obtain the optimal ozone concentration of 25 mg/L.The gas flow rate was 0.4 L/min,the best initial pH is 9,low-concentration ozone and alkaline environment degradation effect is better.Under the optimal operating conditions,the average removal rate of COD is 73.4%,while the removal rate of chroma is 90%,and the biodegradability is improved.The degradation mechanism of H acid in this system is direct oxidation.Combining with the results of UV-Vis and FTIR,it can be inferred that the degradation process of H acid is unstable-SO3H and-NH2.The naphthalene ring is activated and further oxidized into small molecular organic acids,and then continues to oxidize into CO2 and H2O.Finally,the synergistic system was applied to the actual wastewater,and the operation conditions were re-optimized.The optimum ozone dosage was 45 mg/L,and the optimum initial pH was 7.Under the optimum operating parameters,COD removal rate is about 60%and chroma removal rate is over 90%.GC-MS results show that aniline and phenol in wastewater can be degraded.