The Effect Of Natural Organic Matter From Different Sources On Photodegradation Of Phenanthrene And Norfloxacin

In recent years,drug and personal care products(PPCPS)have become an emerging pollutant because of their widespread use.Polycyclic aromatic hydrocarbons(PAHs)are a persistent organic pollutant which is widely found in the environment.Natural organic matter(NOM)is widely used in the environment of surface(soil,water)and is a kind of natural sensitizing agents the main ingredient is humic acid.At present,there are many articles on the effect of natural organic matter on photochemical transformation of organic pollutants,the results show that different natural organic compounds have different effects on the photodegradation of organic pollutants,and the effects of natural organic matter on the photolysis of organic pollutants are discussed in detail,such as the types,concentrations,free radicals and pH values of humic acids.However,there is no definite conclusion on the relationship between humic acid structure,fuirictional group and photolysis of organic pollutant.Therefore,this study extracted humic acid from black soil,white soil type paddy soil,organie manure and corn stalk with different structure,and represented natural organic matter from various sources,and studied their effects on the degradation of Phenanthrene and norfloxacin by Starlight respectively.The results of the study are as follows:(1)Seven kinds of natural organic matter from different sources were extracted,which were black soil humic acid(N1),black soil fixlvic acid(N2),white soil type Paddy soil humic acid(N3),white soil type paddy soil fulvic acid(N4),organic fertilizer humic acid(N5),organic fertilizer fulvic acid(N6),straw soluble organic matter(N7),and seven kinds of natural organic matter were characterized.Analysis of UV-vis spectra found that in the range of wavelength 290nm-800nm,the absorbance value is decreased in the form of humic acid of black soil,humic acid of white soil type paddy soil,organic fertilizer humic acid,organic fertilizer rich acid,white soil type paddy soil rich acid,black soil rich acid and straw dissolved organic matter.It was found that the proportion of carboxyl component in natural organic matter was decreased in the order of humic acid,white paddy soil humic acid,organic fertilizer humic acid,organic fertilizer rich acid,white soil type paddy soil rich acid,black soil rich acid and straw dissolved organic matter.(2)The photodegradation of phenanthrene and norfloxacin met the pseudo first-order reaction kinetics.The degradation rate of phenanthrene in natural organic matter solution ranges from black soil humic acid,white soil type Paddy soil humic acid,organic fertilizer humic acid,organic fertilizer fulvic acid,white soil type Paddy soil fulvic acid,black soil fulvic acid,straw soluble organic matter reduce.The degradation rate of norfloxacin in natural organic solution is from black soil humic acid,white soil type Paddy soil humic acid,organic fertilizer humic acid,organic fertilizer fulvic acid,white soil type Paddy soil fulvic acid,straw soluble organic matter,black soil fulvic acid decreased in turn.The degradation rate of phenanthrene and norfloxacin was determined by the UV absorption of natural organic matter at 254 nm,the UV absorption of natural organic matter at 280 nm,and the absorbance of natural organic matter.The correlation was extremely significant,and there was a significant negative correlation between the ratio of infrared absorption of natural organic matter at wavenumbers 2926cm-1 and 1717cm-1.From this,it can be concluded that the higher the degree of humification and the stronger the light absorption ability of natural organic matter,the faster the degradation rate of phenanthrene and norfloxacin;the greater the proportion of carboxyl groups in natural organic matter components,the faster the degradation rate of phenanthrene and norfloxacin.(3)The concentration of natural organic matter has a significant effect on the photodegradation rate of phenanthrene and norfloxacin.With the concentration of natural organic solution ranging from 0.5 mg·L-1 to 2mg·L-1,the degradation rates of phenanthrene in blace soil humic acid,white soil type Paddy soil humic acid,organic fertilizer humic acid solution were decreased by 16.9%,18.1%,and 22.7%;The degradation rates of blace soil fulvic acid,white soil type Paddy soil fulvic acid,and organic fertilizer fulvic acid solution were decreased by 16.2%,19.3%,and 16.4%;the degradation rate of phenanthrene in straw soluble organic matter solution was decreased by 13.2%.With the concentration of natural organic solution ranging from 0.5mg·L-1 to 2mg·L-1,the degradation rates of norfloxacin in black soil humic acid,white soil type Paddy soil humic acid,organic fertilizer humic acid solution were decreased by 30.9%,28.6%,and 25.6%.The degradation rates of norfloxacin in black soil fulvic acid,white soil type Paddy soil fulvic acid,and organic fertilizer fulvic acid solution were decreased by 24.4%,17.7%,and 24.4%;the degradation rate of norfloxacin in straw dissolved organic matter solution was decreased by 22.6%.(4)The difference in pH of the natural organic solution has an effect on the photodegradation of phenanthrene and norfloxacin.The degradation rate of phenanthrene in natural organic solution increases with the pH value of the solution.Norfloxacin degrades most rapidly when the natural organic solution is neutral,and the photodegradation of norfloxacin is inhibited under pH-saturated and partially-alkaline conditions.