Research On The Removal Of BDE209,Cd²⁺/Pb²⁺ Combined Pollution In Water/Sediment System By Pseudomonas Aeruginosa

Polybrominated diphenyl ethers?PBDEs?-heavy metal combined pollutant is ubiquitous in e-waste dismantling area.These two types of pollutants have caused a global environmental pollution and serious threat to the ecosystem and human health,due to its properties of long-existence and the accumulation in environment.Decabromodiphenyl ether?BDE209?is the most abundant PBDEs homologue in environment,Cd²⁺ and Pb²⁺ are typical heavy metals in e-waste dismantling area.This research focused on BDE209-Cd²⁺/Pb²⁺ combined pollutant in water/sediment system,and investigated the distribution behavior of BDE209,Cd²⁺,Pb²⁺ in water/sediment system systematically.We degraded BDE209 by P.aeruginosa,which was isolated from the sediment of the e-waste dismantling area,and analyzed the action mechanism of various factors on the degradation process from the angle of the contaminants interact with bacteria and sediment.The results of the study had the vital significance in the ecological risk control of PBDEs-heavy metal combined pollutant in water system.A series of adsorption experiments were carried out With sediment as adsorbent and BDE209,Cd²⁺,Pb²⁺ as adsorbates.Adsorption results showed Quasi secondary dynamic equation could well fit the process of BDE209 adsorption in the water/sediment system;Quasi first-order kinetics equation and quasi secondary dynamics equation could well simulate the adsorption process of Cd²⁺ and Pb²⁺.The maximum adsorption capacity of BDE209?1 mg/L?in sediment was 16.15 ?g/g and the maximum adsorption rate of Cd²⁺,Pb²⁺?20 ?M?were 85%,73% respectively.Humus played a vital role in the distribution process of BDE209,Cd²⁺ and Pb²⁺ in water/sediment system.The study found that BDE209,Cd²⁺,Pb²⁺ tend to transferring from sediment to aqueous phase when humus existed,and the trend of Cd²⁺ was more significant than Pb²⁺,the distribution of BDE209 in water/sediment system was mainly affected by water-soluble humus.By conducting the degradation experiments of BDE209 in combined pollution water/sediment system,the results showed that the maximum degradation rate of BDE209?1 mg/L?was 38.8% within 6⁸ d;Glucose,humus,phenol,surfactant has a certain influence on the degradation process.Glucose could provide carbon source for bacteria,and the process of degradation was improved when Glucose input quantity was 200 mg/L;humus showed inhibitory effect on the degradation of BDE209,due to the interaction with BDE209;Phenol could promote the degradation of BDE209 by Co-metabolism;the effect of surfactant on BDE209 degradation was Caused by changing bacteria growth mass,BDE209 solubility,and the bacteria surface hydrophobicity.Through the microstructure of bacteria and biodiversity experiments,we found BDE209,Cd²⁺,Pb²⁺ showed different degrees of toxic effects to bacteria,and The order of pollutants biotoxicity was as follows: 20 ?M Cd²⁺>20 ?M Pb²⁺>1 mg/L BDE209.