| Explosive compound refers to the compound composed of a single molecular structure,which can produce explosive reaction and do work to the surrounding medium under appropriate external energy stimulation.The commonly used explosives are mainly 2,4,6-trinitrotoluene and RDX and other conventional explosives,but with the needs of the military battlefield,a batch of high energy explosives have been synthesized and put into use,such as Tetryl,nitroguanidine and CL-20.Explosives in military and civilian activities to people’s behavior and production bring a lot of convenience,instead of manpower.However,with the widespread use of explosives,the environmental harm is more and more serious,and the remediation of explosive contaminated sites is more and more urgent.The main research contents and conclusions are as follows:(1)Investigation of soil explosive contamination and its occurrence in ammunition destruction plantThe soil explosive pollution degree and the occurrence state of explosives in the soil of a military ammunition destruction site in Jilin Province were studied to provide targeted strategies for the remediation of explosives and heavy metal contaminated soil.The physical and chemical properties and the content of common heavy metals in the contaminated soil in the ammunition destruction area were analyzed.The thermodynamic behavior of contaminated soil samples was characterized,and the occurrence state of explosive pollutants and the combined pollution characteristics of explosives and heavy metals were discussed.The total content of TNT in the whole soil sample reached 1.66×10~4 mg/kg,which was much higher than the EPA-recommended soil TNT guideline limit(80mg/kg),and the RDX exceeded the guideline limit for soil environment(BRIENW,4.7 mg/kg),the degree of explosive pollution was more serious,and the soil fine particle enrichment trend was shown;the destruction activity also caused the increase of heavy metal contents such as Pb,Cu,and Zn in the soil.Affected by factors such as heavy metals and organic matter in the soil,the pyrolysis behavior of the long-term aged explosive pollutants in the soil is obviously different from that of the free explosive molecules,and the pyrolysis temperature increases and the process is prolonged.(2)Advanced oxidation remediation of TNT contaminated soil in the destruction areaTNT in explosive-contaminated soil has limited hydrolysis capacity under alkaline conditions.By adjusting the pH of the hydrogen peroxide solution,and using sodium bicarbonate,sodium molybdate,and boric acid to activate the hydrogen peroxide solution under alkaline conditions,it can effectively The degradation rate of TNT in soil was improved.Under the condition of ultrasonic oscillation,the degradation rates of TNT were40.05%,24.99%and 40.04%,respectively.Under alkaline conditions,sodium percarbonate and sodium persulfate undergo a decomposition reaction to generate effective active oxygen and act on TNT in the soil,which can effectively reduce the content of TNT.The sodium percarbonate system had the best degradation effect on TNT in this study,and the degradation efficiency was 53.53%.Using the ultrasonic oscillation method,the degradation efficiency of TNT can be effectively improved by the activated system.The main reason for limiting the degradation efficiency of TNT in soil is due to the limited desorption ability of TNT from the soil particle surface,thus limiting the amount of TNT involved in the reaction.The addition of surfactant can effectively desorb TNT from the surface of soil particles and improve the degradation efficiency of TNT,and the degradation efficiency is as high as 82.28%.BNT colorimetry and electron paramagnetic resonance were used to identify the reactive oxygen species produced by each activation system.The main reactive oxygen species were singlet oxygen,superoxide anion,and hydroxyl radicals.This is the basis for the subsequent exploration of TNT in the peroxide-degraded explosive-contaminated soil.The reaction mechanism provides the basis. |
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