Study On Oxygen Consumption And Degradation Of Substituted Phenols In Simulated Seawater And Its Quantitative Structure-Activity Relationship

Substituted phenols are a series of potential organic pollutants which can always be detected in seawater. The oxygen consumption and degradation of substituted phenols had been studied in opening and close simulated seawater in this paper. The results were showed as follows:In opening simulated seawater, dissolved oxygen first decreased and then increased. The biodegradation of substituted phenols was the major reason which makes the low dissolved oxygen of this system. The oxygen consumption was correlative with biodegradation rate constants. The degradation process satisfied the first-order kinetic equation in this opening system.5-days biochemical oxygen demand (BOD₅) of substituted phenols was detected in close simulated seawater. The relationship between BOD₅ and substituents was showed as follows: As to methyl substituted phenols: o-cresol< m-cresol m-aminophenol>p-aminophenol; as to the same substituted place: cresol>aminophenol. The biochemical oxygen demand process satisfied the first-order kinetic equation in this close system.Lg Kow,¹X^V, ²X^V,MW,H_f,E_HOMO,E_LUMO and μ has been used as structure parameters to develop the quantitative structure-biodegradability relationship model and quantitative structure-BOD₅ relationship model. Stepwise regression analysis showed that combination of ¹X^V and lg Kow fit biodegradation rate constants of substituted phenols well. The model was developed as follows:Lgk=0.1521g Kow -0. 299²X^V-0. 208n=8, R=0. 944, F=20. 412, Sig. =0.004The combination of MW and lg Kow can be used to describe BOD5 of substituted phenols well. The model was developed as follows:BOD₅=-0.034MW+0.4471g Kow +5.57n=10, R=0.878, F=11.741, Sig.=0.006...