The Research On The Biodegradation Of 1-chloronaphthalene And 2-chloronaphthalene

1-chloronaphthalene(1-CN) and 2-chloronaphthalene(2-CN) have received extensive atention in recent years due to their wide spread use and ubiquity in the environment.They are widely distributed in the air, water, sediment, soil, and organisms. Research suggests that metabolic breakdown of phthalate esters by microorganismsis considered to be one of the major routes of environmental degradation for these widespread pollutants due to their unpractical and the environment secondary pollution of the ultrasound and the photolysis. Therefore, taking one naphthalene and 1,4-dichloronaphthalene degradation strain as the subjects investigated, on the only carbon and energy metabolism, and a matrix of naphthalene circumstances, has studied different concentrations of 1-chloronaphthalene and 2-chloronaphthalene biodegradation and the kinetics model. At the same time metabolites also were studied.The results show that, the strain could completely degrade low concentrations of 1-chloronaphthalene and 2-chloronaphthalene under the single matrix condition, and degradation rate was fast. 10mg/L, 20mg/L 1-chloronaphthalene and 2-chlorona- phthalene have been thoroughly degraded in a few hours. With the concentration increasing, the 1-chloronaphthalene and 2-chloronaphthalene degradation rate decreases. The removal rates of 1-chloronaphthalene and 2-chloronaphthalene were respectively 52.8% and 56.74% after six days. It also found that in the same concentration and the same degrading conditions, 2-CN degradation rate were greater than 1-chloronaphthalene.10 mg/L of 2-CN in 2 h, has been thoroughly degradation. And 10 mg/L of 1-CN need 1 h. The same 20 mg/L of 2-CN in 3 h, has been thoroughly degradation. And 20 mg/L of 1-CN need to 7 h.The presence of naphthalene matrix promoted degradation of 1-CN and 2-CN, 50 mg/L 1-CN and 2-CN can be completely degradated. The results of non-line curve fitting by using the 1stOpt named Origin indicated the kinetics model of 1-CN and 2-CN degradation could be expressed by metabolic degradation mode l and Model 3 in the absence of growth and energy.1-CN, 2-CN and its derivatives were detected by gas chromatography/mass spectrometry. After hydroxylation reactions a ring-cleavage step occurs which leads to chlorinated naphthol derivative and CN-diols derivative. Their respective ring were cleavaged. Because of the different positions of the hydroxyl, it may be the formation of several isomers. Additionally, their respective ring-cleavage products C10H5ClO4. C10H5ClO4 can be transformed into their respective C9H5ClO2. Oxidation of either of derivatives catalyzed would produce chlorosalicylic acid. The pathway of 2-CN was the same as 1-CN.