[Degradation of 2, 4-D by combined catalytic dechlorination and biological oxidation]

In this paper, Pd/Fe nanoparticles were used to degrade 2,4-D. Then the resulted solution of 2,4-D dechlorination was biological oxidized by activated sludge. And the effects of initial pH, activated sludge volume, initial contaminant concentration and temperature on the removal of PA were studied. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) was used to study microbial community structure. And High Performance Liquid Chromatography (HPLC) was employed to determine and analyze the degradation process of target pollutant. The conclusions can be summarized as follows: (1) Pd/Fe can degrade 2,4-D efficiently, 2-CPA was the intermediate product, and the end product was PA. (2) Compared with 2,4-D, the dechlorination product PA has lower biological toxicity, and can be more easily degraded by activated sludges. (3) pH = 7, 50 mL activated sludge/200 mL solution, PA initial concentration of 14. 6 mg L-1 and 30°C favored the PA removal. Under suitable conditions, the removal rate of PA can reach to 84. 3% after 96 hours.