Photocatalytic Degradation Of Nitrogen-containing Wastewater And Performance Optimization Of Perovskite Oxides

With the improvement of people’s living standards,the environmental problems that come with it have become more prominent.The state and industry have set higher requirements for the emission standards of ammonia nitrogen,nitrate nitrogen,and nitrite nitrogen in the wastewater.This research explores the treatment process of nitrogen-containing wastewater by preparing and modifying perovskite-type oxides,using photocatalytic technology,and using hydrogen peroxide or formic acid as oxidants or reducing agents.In the experiment,a sol-gel method and citric acid as a complexing agent were used to prepare perovskite oxides with Mn,Fe,and Co as B potential ion.It was found that La Mn_0.8Fe_0.2was prepared by doping with Fe has the best Catalytic performance.The SEM,EDS,XRD,FT-IR,and BET analysis of the prepared catalyst is performed to infer the relationship between the structure and properties of the catalyst;the combined process treatment effects such as UV,H₂O₂,and catalyst exist by comparison,it was found that the UV+catalyst+H₂O₂process has the best effect in removing nitrite nitrogen.And we get the best process conditions for obtaining 100 mg/L nitrite nitrogen simulated wastewater:250 mg/L catalyst,3 m L H₂O₂,reaction time in 60 min,the nitrite nitrogen degradation rate can reach 100%.The orthogonal test method was used to explore the optimal process conditions for degrading ammonia nitrogen simulated wastewater,and the p H value of the solution was determined by a range analysis.The optimal process conditions for the test were determined based on the analysis:when the initial concentration of wastewater was 100 mg/L,the initial p H was 12,the amount of catalyst was 500 mg/L,the amount of H₂O₂was 8 m L,and the reaction time was 80 min.Under these conditions,the ammonia nitrogen was converted by 100%,and the selectivity of N₂was95.35%.The single-factor test method was used to investigate the degradation process of simulated nitrate nitrogen wastewater,and the optimal process conditions were:when the nitrate nitrogen concentration was 100 mg/L,the solution p H was 4,the catalyst dosage was 500 mg/L,and the formic acid dosage was 50 mmol/L,after 6 h of reaction time,the degradation rate of nitrate nitrogen was 46.65%,and the selectivity of N₂was 36.23%.In the investigation of the actual degradation of nitrogen-containing wastewater,it was found that this method has a better effect on the treatment of ammonia nitrogen and nitrite nitrogen,and it is still necessary to improve the process and modify the catalyst for nitrate nitrogen.