Treatment Of Methyl Orange Dye Wastewater By DBD Plasma Combined With Modified Activated Carbon

With the rapid development of industry,the pollution of water resources is becoming more and more serious,and the discharge of dye wastewater is one of the major causes of water pollution.In order to meet the ever-changing market demand,dyestuffs are frequently produced and used with new processes,technologies and additives,making them increasingly difficult to degrade.Traditional treatment methods are difficult to achieve the desired results,and if untreated or substandard dye wastewater is discharged into natural waters,it can harm aquatic life and furthermore pose a threat to human health.Dielectric barrier discharge(DBD)plasma technology is a kind of advanced oxidation technology,which is ideal for treating wastewater,but there are disadvantages such as low energy utilization rate and complicated equipment,which make it difficult to apply in practice.Activated carbon adsorption method is more widely used,but it only enriches pollutants,is transferring pollutants,and does not remove them completely,and more importantly,there is also the problem of regeneration reusability.In response to the above,this paper adopts DBD plasma combined with modified activated carbon(CTAB-AC)to treat methyl orange(MO)simulated dye wastewater.The modified activated carbon not only has enhanced adsorption capacity,enriches the pollutants more effectively,increases the contact time between the active substance and the pollutants,and improves the degradation rate,but also the activated carbon can be reused in the combined system.The main results are as follows.Firstly,the separate DBD plasma was used to treat MO dye wastewater,and the experimental results showed that: when the input electric power increased,the degradation rate of MO also increased continuously;when the discharge spacing slowly increased,the degradation rate of MO gradually decreased;when the initial concentration and initial conductivity of MO solution were higher,the degradation of MO was more difficult and the degradation rate was lower;under acidic conditions,the degradation effect of MO was better than under neutral and alkaline The degradation effect of MO was better under acidic conditions than under neutral and alkaline conditions.The multi-factor orthogonal experiments showed that several factors influenced the degradation rate of MO in descending order: input electric power,initial concentration of solution,initial p H,and discharge spacing.The optimal experimental conditions were 115 w input power,6mm discharge spacing,100mg/L initial concentration of MO solution and 3.45 initial p H.After 20 min treatment under the optimal conditions,the degradation rate of MO was 83.8%,and the degradation process of MO was in accordance with the primary reaction kinetics under the optimal treatment conditions.Cetyltrimethylammonium bromide(CTAB),a cationic surfactant,was used to modify the activated carbon,and the optimal modification conditions were: CTAB concentration of 0.7mmol/L,modification temperature of 30℃,and modification time of 8h.In the DBD plasma combined with CTAB-AC treatment MO system,when the input electric power was 115 w,the discharge spacing was 6mm,the initial concentration of MO solution was 100 mg/L,the initial p H was 6.53(original p H),the initial conductivity was 8.94μs/cm,and the dosage of CTAB-AC was 0.5g,the degradation rate of MO was 84.92%,which was higher than that without The degradation rate of MO was 84.92%,which was 8.32% higher than that without CTABAC.In the reusability experiment of CTAB-AC,the degradation rate of MO could reach more than 78% after 5 times of reuse,which indicated that it has good stability and high potential for practical application.The comparison of different systems for MO degradation revealed that the combined system of DBD plasma and CTAB-AC had the best effect in treating MO,DBD plasma alone had the second best effect,and activated carbon alone had the worst effect.Finally,the mechanism of MO treatment by the combined system was initially explored,and the experimental results showed that the COD was well removed during the treatment process,with a removal rate of 53.68%,and the p H value was continuously reduced during the degradation process,which would eventually be maintained at about 3.