Study On Electrochemical Advanced Treatment Technology Of Low Pollution Oily Wastewater

The rapid development of modern society and the significant improvement of industrial technology have led to an increase in water consumption.At the same time,the amount of wastewater discharged has also increased.The composition of oil-containing wastewater is complex,and the content of COD and ammonia nitrogen is high,and it is discharged into the water body has caused serious pollution.Not only affects the environment,but also causes harm to the human body.Electrocatalytic oxidation technology has a good ability to degrade organic matter and has attracted extensive attention from scholars.The paper takes the biochemical effluent of oily wastewater from a refinery in Tianjin as the research object.Because of its original effluent,it needs to reach the standard further.The experiment uses electrocatalytic oxidation technology to carry out advanced treatment of such sewage.In the paper,the effect of particle electrode prepared by different electrode materials,electrode structure and different impregnation methods on the biochemical effluent of Tianjin refinery was investigated and orthogonal experiment to explore optimal experimental conditions for three-dimensional electrodes.The COD and ammonia nitrogen removal rate were used as indicators to screen out suitable particle electrodes.urface structure of the particle electrode was characterized by scanning electron microscopy（SEM）.The composition information of the particle electrode material was obtained by X-ray diffraction（XRD）,and the stability experiment of the particle electrode was carried out.The results show that when the two-dimensional electrode experiment is carried out,the anode is selected as the DSA plate electrode,and when the cathode is used as the graphite plate,the treatment effect on the biochemical effluent is the best,and the removal rates of COD and ammonia nitrogen are the highest,which are 67.7%and65.7%,respectively.Under the same conditions,the three-dimensional electrode with activated alumina（γ-Al₂O₃）as the particle electrode had better treatment effect on biochemical effluent.The COD and ammonia nitrogen removal rates were 72.6%and89.5%,respectively,which increased by 7.3%and 36.4%,respectively.In the electrode for preparing particles,the particle electrode prepared by the stepwise dipping method and ultrasonic assisted has better treatment effect on biochemical water,and the removal rates of COD and ammonia nitrogen are 89.9%and 100%,respectively.Orthogonal experiments showed the optimal reaction conditions for three-dimensional electrodes were reaction conditions at 0.4 A,particle electrode at about 15 g/L,plate spacing at 2 cm,and reaction time at 60 min.Finally,the particle electrode was characterized by surface structure and electrode material.The SEM image indicated that both Sn and Ce were successfully loaded ontoγ-Al₂O₃,and Ce acted as a dispersant successfully.Ultrasonic impregnation allows the active component to be more evenly distributed over the particles.The results of XRD show that both Sn and Ce are successfully loaded on the particle electrode in the form of oxides,namely Sn O₂and Ce O₂,respectively.The peak value of Ce O₂is weak,indicating that Ce O₂only acts as a dispersant,making the distribution of Sn O₂onγ-Al₂O₃more uniform.And the experiment of particle period stability shows that 65 min is a cycle.After 5 cycles,the COD removal rate of the particle electrode for wastewater is reduced from the initial89.9%to 83.2%,and the removal rate is reduced by about 7.4%,but all are in More than 80%,with a certain stability.