| In recent years,with the development of society,energy materials such as petroleum and biomass have been widely used,and the leakage of petroleum in the soil and the improper treatment of waste biomass have caused more and more serious organic pollution to the environment.As an efficient,fast and mature technology,the heat treatment process has been widely studied and applied in the process of thermal remediation of petroleum-contaminated soil and biomass waste recycling.However,the thermochemical treatment of organic pollutants will produce Dissolved Organic Matter(DOM),which may have a certain impact on the water color,odor,COD,BOD and other water properties of the aquatic ecosystem.At the same time,DOM will participate in a series of biogeochemical processes such as numerous microbial activities,plant growth,and the migration and conversion of pollutants in the environment.Therefore,the understanding of its composition and function has extremely important environmental significance.In this paper,the organic pollutants(oil-contaminated soil and biomass waste)are subjected to heat treatment,and the characteristics of the DOM produced are analyzed in detail,and its phytotoxicity and the function of degrading carbamazepine antibiotics are studied.The specific research content and the results are as follows:1.Research on the dissolved organic matter produced by the pyrolysis and remediation process of organic pollutants in petroleum-contaminated soil.Pyrolysis,as a convenient and fast technology,has been proved to be promising in the remediation of oil-contaminated soil.However,little is known about the dissolved organic matter(DOM)associated with pyrolyzed oil-contaminated soil and its environmental impact.Herein,optical spectroscopic techniques(i.e.,absorbance and fluorescence)were adopted to reveal the relationship between the pyrolysis temperature and the characteristics of the DOM and the associated phytotoxicity.Results show that one of the main factors determining the properties and phytotoxicity of DOM leached from the pyrolyzed soil is the critical temperature(approximately 325℃)during pyrolysis.When the temperature was lower than 325℃,more types and quantities of DOM,mainly fulvic acid-like substances,were desorbed from the soil with the temperature,which have little effect on wheat growth.However,when the temperature was in the range of 325-550℃,the type and quantity of DOM increased first and then decreased as the temperature increased,during which the organic matter in the soil decomposed.The wheat growth was first inhibited and then promoted.Finally,the correlation between the spectral indices of DOM with the phytotoxicity suggested that fluorescent components identified by parallel factor analysis were positively correlated with phytotoxicity.This study indicates the pyrolytic remediation of oil-contaminated soil should avoid some critical temperature ranges.2.Research on the dissolved organic matter produced by the hydrothermal carbonization process of waste biomass organic pollutants.Hydrothermal carbonization(HTC)is an extremely attractive alternative waste management method.Dissolved organic matter(DOM)in the process water is basically an unwanted by-product,with high chemical oxygen demand and high dissolved organic carbon content,in addition to In addition to certain toxicity,the active species may also be used to degrade other pollutants.This study analyzed in detail the characteristics of dissolved organic matter produced by the hydrothermal carbonization process of waste biomass and its degradation of carbamazepine organic pollutants.The results show that the DOM obtained by hydrothermal of different biomass mainly contains a fluorescent component,and the concentration of DOM obtained after hydrothermal of sawdust is the lowest,and the photolysis efficiency is the highest.At the same time,with the change of hydrothermal time and hydrothermal temperature,It is determined that the photodegradation efficiency of DOM obtained by hydrothermal 3 h at 200℃ is the best,and it has a significant enhancement effect on the photodegradation of carbamazepine. |
