Combination Of Fenton Process And Phanerochaete Chrysosporium For The Removal Of Bisphenol A In River Sediments

In recent years,with the development of industry and agriculture,more and more attention has been paid to sediment pollution in river channels and secondary pollution of water bodies caused by sediments.Bisphenol A is a common endocrine disruptor that is toxic and harmful to the reproductive system,nervous system and embryonic development of humans and other organisms.Because of its wide application in industry and life,with the recycling of materials,many studies have reported that bisphenol A has appeared in the waters of many places in China.Although traditional methods can also remove bisphenol A in water,e ach has its drawbacks.This experiment uses a novel method to treat the river sediment.This method is a combination of Fenton technology and the addition of Phanerochaete chrysosporium.The main contents of this study are as follows:?1?The suitable pH condition of traditional Fenton reaction was about 3.In order to break this limitation,the beta cyclodextrin??-CD?was added to improve the efficiency of Fenton reaction.Firstly,the condition of single Fenton reaction was optimized in liquid matrix.The amount of FeSO₄,ratio of Fe²⁺to H₂O₂ and amount of?-CD were carried out in optimization experiments.The sequence of optimization is FeSO₄,Fe²⁺/H₂O₂ and?-CD.The best values of the three variables were FeSO₄?270mmol/L?0.5mL,Fe²⁺/H₂O₂ 1:4?v/v?,?-CD?13 mmol/L?,1 mL.?2?Fenton process?the best value of three conditions obtained by optimization experiment?was used to combined with Phanerochaete Chrysosporium techmology to remove bisphenol A from river sediments.The results showed that the remove rate of bisphenol A was 58.23%after the combination treatment,which was significantly higher than that the control group treated with Fenton process alone and the control group treated with Phanerochaete Chrysosporium alone.Their remove rate of bisphenol A was 14.48%and 21.59%,respectively.Small organic acids have a direct effect on pH in the system.The concentration of oxalic acid reached the maximum in5⁸ days,which was related to the growth of white rot fungi.At the end,the concentration of oxalic acid,malic acid and fumaric acid decreased to the lowest level,which was related to the gradual decline of fungus'growth.The presence of beta cyclodextrin has a great influence on the removal rate of bisphenol A.The possible reasons:?-CD was a chelating agent to promote Fenton reaction,and as a bioactive substance,can promote the growth of white rot fungi.Therefore,the removal rate of bisphenol A was improved.?3?In order to study the mechanisms that the remove rate of bisphenol A of combination treatment is higher than that of two single treatment methods.During the28 day treatment process,the pH,ferrous ion(Fe²⁺)concentration,H₂O₂ concentration,concentration of three organic acids,enzyme activity of lignin peroxidase?LiP?and manganese peroxidase?MnP?were monitored.The results show ed that in this study,Fenton technology is not as a pretreatment or aftertreatmetn,but an organic involved in the process of combined degradation of bisphenol A.The combined method is better than the single method.The change of enzyme activity and the change of Fe²⁺and small organic acids showed that there were likely synergistic effects between Fenton technology and Phanerochaete Chrysosporium treatment.On the one hand,the presence of Fenton reagents stimulates the growth or development of white rot fungi.On the other hand,the organic acids and H₂O₂ generated by Phanerochaete Chrysosporium can promote chemical Fenton reaction.At the beginning of degradation,Fenton reagent played a major role in combined treatment.At the end,fungi played a major role in removing bisphenol A.In addition,under the presence of?-CD,the removal rate of pollutants is higher than that of the absence of?-CD,which might be attributed to that cyclodextrins can form ternary complex with ferrous ions and pollutants,thus promoting the release of pollutants from sediment,and thus increase the removal rate of pollutants.The combined treatment method used in this study with more mild reaction conditions than the traditional Fenton technology,and the reaction time is less than the general microbial degradation pollutants.Importantly,the removal rate is improved obviously.It is provide a new way for the treatment of organic pollutants from sediment.