Experimental Study On Degradation Of Organic Wastewater Containing Formaldehyde And Benzoic Acid By Non-thermal Plasma Combined With Adsorption

In this paper,formaldehyde as small molecular material and benzoic acid as benzene ring refractory material were used to simulate alkyd resin paint wastewater.Degradation of simulated alkyd resin paint wastewater by using dielectric barrier discharge non-thermal plasma?NTP?technology combined with adsorption method.Using activated carbon?AC?and?-Al₂O₃ as the main adsorbent,the degradation purification law and reaction kinetics of wastewater from formaldehyde,single component wastewater of benzoic acid and two mixed components of wastewater in single adsorption,single NTP oxidation and NTP combined with adsorption under three different process conditions were investigated.The study of single component wastewater of formaldehyde and benzoic acid in individual NTP degradation showed that the degradation rate of COD in wastewater decreased with the increase of initial concentration in the applicable range,and with the increase of discharge voltage and aeration,the trend of increasing growth rate slowed first.With the increase of discharge voltage and power,the effective energy utilization rate of the system increases and decreases.From the response surface analysis,it is shown that the purification effect of wastewater is positively correlated with discharge time,voltage and aeration,and negatively correlated with the initial concentration,and the discharge voltage is the most significant factor,followed by voltage,aeration and concentration.In addition,in the process of degradation of benzaldehyde wastewater,the color of wastewater will change significantly,from the initial colorless to brown and then to colorless.The results show that the intermediate products such as hexadiene diacid,butene diacid,hydroquinone and benzene quinone will be produced during the degradation process.Compared with the degradation of wastewater,it was found that benzoic acid was more difficult to oxidize than formaldehyde.NTP oxidation combined with AC adsorption degradation of two-component mixed wastewater showed that the purification effect under the combintion is better than the effect of individual AC adsorption and NTP oxidation.The initial discharge of the reaction was not stable with the adsorption of AC,the two of them played a role of degradation in the medium term,and NTP oxidation was the main stage.The kinetic analysis of the oxidation degradation process shows that the reaction does not always follow a certain kinetic model,and the reaction series changes with the change of the concentration ratio,time and other conditions of the component.The higher the concentration of benzoic acid and the shorter the time,the more in line with level two dynamics,whereas it is closer to the first level kinetics.At the same time,it is found that the higher the content of benzoic acid,the worse the biochemical nature of wastewater,the longer it takes to reach the same degradation rate.Wastewater degradation is a complex mass transfer-reaction process,and the purification rate and effect are determined by factors such as gas-borne mass,liquid mass transfer,gas-liquid interfacial mass transmission,adsorption properties and chemical reaction rate.Adding the right amount of adsorbent,access to the right amount of air and other ways are helpful to improve the purification effect and shorten the treatment cycle.In this study,NTP technology combined with adsorption method was used to purify mixed organic wastewater,with the aim of bringing it closer to industrial practice.At the same time,on the basis of experiments,the dynamics are investigated,and the experimental data and theoretical basis are provided for the industrial application of collaborative technology.Figure[36]Table[12]Reference[81]...