Study On The Waste Gasification Scrub Wastewater By Persulphate Oxidation

With the ever-increasing awareness of environmental protection in every countries,making use of gasification-reforming technology to effectively use municipal solid waste not only alleviate the problem of urban garbage pollution,but also solve the problem of energy shortage in China,The development of a method that can effectively solve the secondary pollution of gasification-reforming technology will contribute to the promotion of gasification-modification technology.In this study,the scrubbing wastewater obtained after the municipal solid waste gasification-reforming technology was the target treatment and the polycyclic aromatic hydrocarbons(phenanthrene and pyrene)are the target poisons.By adjusting the variables in the reaction,discovering methods for effectively handling environmental loads,setting up environmental load purification system,and optimizing operating conditions.As known,the main pollutants in scrubbing wastewater are phenanthrene and pyrene,which are the main representative substances of polycyclic aromatic hydrocarbons.The degradation is difficult and the degradation mechanism is complex.In this paper,a series of quantitative analysis of activated persulfate degradation of polycyclic aromatic hydrocarbons was carried out.The influencing factors affecting the degradation of phenanthrene and pyrene and the variation of degradation efficiency were discussed.Results show that:(1)The components of the filtration system scrubbing wastewater in the collected waste gasification process were analyzed.The main components of polycyclic aromatic hydrocarbons(PAHs)were higher than 75%,and the content of phenanthrene and pyrene in polycyclic aromatic hydrocarbons was the highest,accounting for about 60%.Pre-experiment was carried out by preparing simulated wastewater with a concentration of 100 mg·L-1.No valid target was found by GC-MS.By increasing the standard solution to simulate the wastewater concentration,discussing PAHs sulfate oxidative degradation through the main intermediates dibenzothiophene,diphenyl-2,2’-diformaldehye,1-hydroxy-9-fluorenone and phenanthrenequinone..(2)Real scrubbing wastewater was used to discuss the effect of single factor variables on transition metal activated persulfate.The concentration of phenanthrene and pyrene was about 100 mg·L-1.The best conditions of persulfate activated cobalt catalyst degradation phenanthrene and pyrene is 15 wt%loading of catalyst,with an amount of 3.0 g,and used in an amount of 0.75 g persulfate,at pH 3,the temperature 30℃ after 4 hours of reaction,the degradation rate of phenanthrene and pyrene can reach 95%or more.The best conditions of persulfate activating iron catalyst degradation phenanthrene and pyrene is 15 wt%loading of catalyst,with an amount of 2.0 g,and used in an amount of 1.0 g persulfate,at pH 3,the temperature 50℃ after 3 hours of reaction,the degradation rate of phenanthrene and pyrene can reach 98%or more.The activation effect of iron catalyst is better than that of cobalt catalyst.(3)The catalyst was prepared by impregnation method,and the best catalyst was characterized by means of specific surface area analysis,scanning electron microscopy and X-ray diffraction analysis.It can be seen from the BET analysis that the specific surface area and pore volume of the catalyst are decreased.The SEM and XRD characterization showed that the active component was well loaded on the activated carbon and effectively played a catalytic role,and the organic matter had a good degradation effect.(4)Discussing on the effect of single factor variable on Fenton oxidative degradation using real scrubbing wastewater.The concentration of phenanthrene and pyrene was about 100 mg·L-1.In the single factor experiment,the Fenton method has the highest degradation rate at pH 3-4,which can reach more than 95%.Over 1 hour to degrade PAHs.The optimum concentration value of H2O2400 mmol·L-1,Fe2+concentration of 80 mmol·L-1 is preferred.As the temperature increased,the degradation rate decreased,at a temperature of 20-30℃,and the highest removal rate of phenanthrene and pyrene.