Study On Removal Pathways And Influencing Factors Of Multiple Phenol Edcs Coexisting Systems

Phenolic endocrine disrupting chemicals are a class of highly toxic organic pollutants that are widely used in the chemical industry.A variety of phenols usually coexist in natural waters,and they are migration and transformation pathways include adsorption,photodegradation and biodegradation,and the interaction between phenolic substances may affect the migration and transformation.Therefore,it is of great practical significance to study the degradation process under the coexistence of various phenolic pollutants.In this paper,phenol,bisphenol A?BPA?and 2,4-dichlorophenol?2,4-DCP?were studied to discuss the adsorption,photodegradation and biodegradation of mixed endocrine disrupting chemicals in water.This paper explored the effects of different factors on the degradation process,and then analyzed the migration and transformation of phenolic endocrine disruptors,and studied the proportion of different degradation pathways.The results were as follows??1?Adsorption behavior of phenols in water by Zaohe river sediment:There was competitive adsorption between the three phenols.The adsorption capacity of Zaohe river sediments on the three phenolic substances was BPA>2,4-DCP>Phonel.The adsorption process of phenolic pollutants accorded with the Quasi-secondary kinetic model,R²>0.9.The adsorption isothermal experiments showed that the isothermal adsorption process of phenol,BPA and 2,4-DCP conformed to the Freundlich model,indicating that the voids and functional groups on the surface of the sediment are non-uniform,and the adsorption process includes both physical and chemical adsorption.The influencing factors showed that the adsorption capacity of phenolic pollutants increased with the initial concentration in a certain concentration range.The pH directly affected the degree of ionization of phenolic substances,and the acidic conditions facilitate the adsorption of phenols in the coexisting system.Temperature had less effect on the three phenols.?2?Through photodegradation experiments of phenolic substances,it was found that wavelength was the primary factor affecting photodegradation,and photodegradation of phenolic substances interacted each other in coexisting systems.In the experiment,the 18W UV lamp gave the best results.After 150min illumination,the degradation rates of phenol,BPA and 2,4-DCP were 34.43%?49.72%?86.81%,respectively.The degradation rate improved with the increase of light intensity.The effects of various influencing factors on photodegradation were related to The factors intensity,phenol structure and its groups,when the wavelength and light intensity are constant.The increase of initial concentration reduced the degradation rate and degradation speed of phenol pollutants.Acid conditions were favorable for phenol photodegradation,while BPA and 2,4-DCP had higher degradation efficiency and degradation speed in alkaline conditions.Fe³⁺and Cl^-exhibited a promoting effect on BPA and an inhibitory effect on 2,4-DCP.The effect of humic acid on the photodegradation of phenolic substances was complex and has dual effects.?3?Through the study of biodegradation of phenols,the biodegradation rate of phenols was low,generally between 1%to 4%.The optimum temperature for the growth and reproduction of microorganisms was about 30?which can degrad phenolic pollutants,and the microorganisms were suitable to neutral conditions.When the temperature or pH was too low or too high,it could cause microbial inactivation or cell rupture.Volatilization and auto-oxidation of phenolic substances were relatively weak.?4?The total removal rates of phenol,BPA and 2,4-DCP respectively were 13.93%,97.77%and 76.12%by static simulation of phenolic contaminants.The adsorption was the main way of migration and transformation process,and its contribution of the three phenols exceeded 75%.