Aerobic Biodegradability Of Fluoroanilines

The aerobic biodegradability of 2-fluoroaniline, 4-fluoroaniline and 2,4-difluoroaniline as the sole substrate was studied in this paper, and their biodegradability was compared and evaluated. The effect of environmental factors on aerobic biodegradability of fluoroanilines was studied. Cometabolism of fluoroanilines and interaction of the fluoroanilines were also investigated. Quantitative structure-activity relationship was studied. Experimental results showed that: (1) The aerobic biodegradability of 4-fluoroaniline is the best, and that of 2,4-fluoroaniline is worst. (2) The dynamic analysis showed that, the biodegradation of fluoroanilines was in accordance with zero order law except the 2,4-difluoroaniline on 8.56mg/L, and their degradation all fit the Monod model. (3) The optimal condition for degradation was pH=6-8, 30℃, 140r/min. (4) The biodegradability of fluoroanilines is increased when the glucose is added as co-substance, and the increase of 2,4-difluoroaniline was the most evident. (5) As co-substance, aniline showed a contradictory effect mixed with 2-fluoroaniline or 4-fluoroaniline, while showed a cooperative effect mixed with 2,4-difluoroaniline, and the optimal concentration of added-aniline is 20mg/L. (6) Activated sludge acclimated by any of these three kinds of fluoroanilines could biodegrade all of them. There is competition between the fluoroanilines, except that 2-fluoroaniline showed lightly cooperative effect on mixing with 2,4-difluoroaniline. ( 7 ) The biodegradation rate of fluoroanilines is markedly correlated with electronic parameter, so the aerobic biodegradation of fluoroanilines is limited by the reaction of organics and enzyme.