Chemical Oxidation Remediation And Microbial Community Diversity Research Of Pahs Contaminated Soil

Polycyclic Aromatic Hydrocarbons(PAHs)are a class of carcinogenic,teratogenic and mutagenic and ubiquitous persistent organic pollutants in the environment.They are difficult to be degraded.The major sources of PAHs include industrial production,oil leakage,incomplete combustion of fossil fuels,and residents' lives.PAHs pollution in the environment is eventually concentrated in the soil environment through natural sedimentation,migration,and other processes.The penetration and diffusion of passive plants were into the food chain and human health were threatened.Chemical oxidation remediation technology is one of the common methods to remedy polycyclic aromatic hydrocarbon-contaminated soils.In this paper,Anthracene was used as a representative of tricyclic polycyclic aromatic hydrocarbons to carry out a small laboratory test on the chemical oxidation remediation method for polluted soil.Qxidants were used such as sodium persulfate,potassium permanganate,Fenton reagent and sodium percarbonate to treat contaminated soil.By changing the oxidant addition amount,reaction time and soil pH,The optimum oxidizing conditions were obtained.Then the optimal oxidant were obtained according to the degradation rate.The degradation products of Anthracene and soil physicochemical properties in oxidized soil under optimal conditions were analyzed.The effect of Anthracene pollution and chemical oxidation on soil microbial community diversity were analyzed by high-throughput sequencing technology.After chemical oxidation treatment,microbial community recovery of the soil was explored under the nature environment.And the following results were obtained:(1)The optimum oxidation conditions and degradation rates for the four oxidants are as follows: the amount of activated sodium persulfate was 2.5 mmol/g,reaction time was 24 h,and soil pH value was 8.38,and the degradation rate was 99.4%;potassium permanganate was added at 2.5 mmol/g,reaction time was 24 h,soil pH was 6.89,and the degradation rate was 97.5%;Fenton reagent was added at 3.0 mmol/g,reaction time was 12 h,soil pH value was 5.24,then the degradation rate was 92.8%;sodium percarbonate was added at 3.0 mmol/g,reaction time was 12 h,and soil pH was 6.89,and the degradation rate was 39.9%.Comparing the degradation effect,activated sodium persulfate is the optimal oxidant.(2)Through activated sodium persulfate remediation and qualitative analysis by GC-MS,the degradation product of anthracene included 9,10-anthraquinone.The soil pH value decreased from 8.38±0.04 to 6.87±0.05,and the organic matter content decreased from 6.38%±0.51% to 5.46%±0.26%.Soil pH value decreased by approximately 1.5,and the organic matter content decreased by 14%.The activated sodium persulfate chemical oxidation treatment didn't convert the low-valent chromium with low-toxicity to hexavalent chromium with highly toxic in the soil.(3)PAH pollution and oxidants all reduced the abundance and diversity of soil microbial communities.After the chemical oxidation,the relative proportion of Bacillus increased and it became the dominant genus in oxidized soil.(4)Under the natural environment,the microbial community abundance and diversity of the soil with chemical oxidation(HFT)increased,but it hasn't returned to the original microbial community structure.The abundance and diversity of the microbial community in the soil without chemical oxidation(DZT)decreased significantly,which was much lower than that of HFT.Bacillus was the dominant genus of HFT,and Paenisporosarcina was the dominant genus of DZT.