Study On The Treatment Of Dye Wastewater By AC Corona Discharge Plasma

The rapid development of industry not only brings us unprecedented convenience but also brings great pollution to the environment,especially water pollution has become a serious environmental problem.And dye wastewater is one of the typical refractory source of water pollutants.Under the rapid development trend of advanced oxidation technology deals with dye wastewater,and dye wastewater has the characteristics of high inorganic salt content,deep color,complex composition,high concentration and strong toxicity,etc.In this paper,the acid light yellow 2G solution was used to simulate the dye wastewater,and the AC corona discharge plasma technology was used to treat it.Discharge voltage,plate spacing,power frequency and processing time,air flow rate,initial pH value,initial concentration of dye and the adding amount of Fe²⁺parameters on the influence of the degradation rate of acid yellow 2G,and the dynamic analysis of the degradation process is carried out.Combining with high performance liquid chromatography-mass spectrometry?LC-MS?and ultraviolet spectrum to analysis of the main degradation products of acid yellow 2G,preliminary deduction degradation pathways and mechanisms of acid yellow 2G,organic dye wastewater treatment for corona discharge technology provides the theory basis for practical application.The experiment results are as follows:?1?The study on the characteristics of corona discharge in the liquid found that the power frequency,solution conductivity and the bare length of the needle had a great influence on the pole-plate voltage.When the conductivity and bare length of the needle are constant,the pole-plate voltage decreases with the increase of the power frequency.And within the scope of the experimental conditions,the pole-the largest plate voltage of power frequency to 5 kHz;When the discharge frequency and the bare length of the needle are constant,the epole-plate voltage decreases with the increase of the conductivity of the solution.When the discharge frequency and conductivity are constant,the pole-plate voltage decreases with the increase of the bare length of the needle.?2?In the experiment,it was found that corona discharge plasma technology has a good effect on the degradation of acidic light yellow 2G.The addition of Fe²⁺can effectively improve the degradation efficiency.Under the condition that the discharge voltage is 150V,the frequency is 5kHz,the initial concentration is 100mg/L,the initial PH is 7.55,the air flow is 1.6l/min,and the electrode spacing is 5mm,the degradation rate is only 79.32%after 30min.The removal rate reached 98.38%when the other conditions were unchanged and only added with 2ml FeSO₄ in the acid light yellow 2G solution.The degradation process was basically consistent with the 1-level kinetic reaction.?3?According to the detection of changes in COD,pH,conductivity and absorbance in the process of degradation,found that,In the process of degradation,the COD value of the acidic yellow 2G solution appears as a decreasing trend,and in the late stage of the reaction,the fluctuation decreases.The pH value of acidic light yellow 2G solution appears as a rapid decline in the early stage.The conductivity value of acid light yellow 2G solution is in the process of degradation,and the whole is on the rise.Through the analysis of ultraviolet-visible spectrogram,it can be inferred that the acidic yellow 2G molecules have been destroyed,mainly producing small molecular substances such as organic acids and aldehydes.?4?The molecular formula of the main intermediate products was determined by high performance liquid chromatography-mass spectrometry.The degradation process of acidic yellow 2G molecules was further deduced by combining the fracture priority of chemical bonds.The main intermediate products are benzene and derivatives of benzene containing substituents.?5?We found that there may be many forms of degradation process of acid yellow 2G by analyzed the degradation mechanism.However,the high-energy electrons,·OH,O₃ and other active particles produced in corona discharge can attack the acidic yellow 2G molecules,because the C-N chemical bonds energy is smaller so it is more likely to be break.And regardless of the degradation pathway,eventually the macromolecular group is decomposed into small molecules and then decomposed into H₂O and CO₂.