Effective degradation of Di-n-butyl phthalate by reusable, magnetic Fe3O4 nanoparticle-immobilized Pseudomonas sp. W1 and its application in simulation

Abstract

Di-n-butyl phthalate (DBP), one of the most widely used plasticizers, has been listed as a priority pollutant because of its toxicity to both humans and animals. In this study, Pseudomonas sp. W1, isolated from activated sludge, was capable of degrading 99.88% of DBP (1000 mg L−1) within 8 days. We immobilized the W1 strain using Fe3O4 iron nanoparticles (IONPs) coated with poly-dopamine (PDA), and further evaluated its DBP degradation efficiency. The DBP degradation performance of W1 was improved by immobilization, exhibiting 99.69% of DBP degradation efficiency on the 6th day, which was 25.68% higher than un-immobilized W1. After three cycles of magnetic recycling and utilization, W1-PDA-IONPs retained 99.6% of their original efficiency. W1-PDA-IONPs were then used to degrade DBP in landfill leachate. When the proportion of raw leachate was ≤50%, DBP could be all degraded by W1-PDA-IONPs within 6 days. In 100% landfill leachate, DBP degradation efficiency after 10 days of incubation reached 66.40%. Furthermore, W1-PDA-IONPs cells in a simulated aeration system could be effectively magnetically separated at aeration rates from 60 to 600 mL min−1. These results highlight the potential of W1-PDA-IONPs in the bioremediation of DBP-contaminated waste water.