| The studies about the high removal efficiency of persistent organic pollutants?POPs?in wastewater has already aroused wide attention.The immobilized-microorganism technique?IMT?,which combines the advantages of biological and adsorption technologies,is a promising approach for organic wastewater treatment.However,some limitation of IMT still existed:such as slow mass transfer,low degradation efficiency and incomplete treatment.Therefore,in this paper,a new marerial of surfactant enhanced biochar immobilized microorganism was studied based on the review of the relevant properties of IMT.And the application of this marerial in treatment of acenaphthene was also investigated,which provides knowledge of the treatment of POPs in wastewater.The main results were concluded as below:?1?To prepare the material of surfactant enhanced biochar-immobilized Pseudomonas aeruginosa,adsorption as one of the commonly immobilization methods was used.The results suggested that the addition of Triton X-100 not only could promote the adsorption of biochar on organic pollutants but also was beneficial to the growth of microorganisms.Moreover,the optimal immobilization time for preparing such material was 24 hours,the loading bacterial liquid and Triton X-100 concentration were 0.2 of OD600 and 5?10 mg·L-1.After 24 hours treatment,the removal rate of acenaphthene by Triton X-100 enhanced biochar immobilized P.aeruginosa material was about 76%?78%,comparing to immobilized material without Triton X-100,which was increasing 20?24%.Furthermore,the changes of ambient temperture?10?50 ??and pH?4.5?10.5?almost had no influence on the removal of acenaphthene.Conversely,it was reduced significantly with the increase of NaCl concetration(0.002?1.5 mg·L-1).?2?Gel embedding,as another commonly immobilization method,was also used to prepare the material of surfacant enhanced biochar-immobilized Pseudomonas aeruginosa beads.In this experiment,there were different promotion effects of Triton X-100 with relatively lower levels on the biochar or bacteria embedded pellets to remove acenaphthene.The removal rate of acenaphthene was highest at a Triton X-100 concentration of 200 mg·L-1,which was about 34%improved compared to no Triton X-100 addition.And the optimum preparation conditions were:biochar addition of 1%,Triton X-100 of 200 mg·L-1,the concentration of bacterial solution and sodium alginate were OD600=1 and 3.5%.In addtion,the changes of pH?2.5?10.5?and NaCl concentration(0?0.2 mg·L-1)had little influence on the removal of acenaphthene,however,it would be conducive to remove the acenaphthene in wastewater with the increase of temperature?10?50 ??.?3?The application effect of surfactant enhanced biochar immobilized Pseudomonas aeruginosa material in a continuous flow system was tested by packed column experiments.Filling height,solution flow rate and particle size all affected the removal of acenaphthene.The removal rate was about 80%and the breakthrough time was 150 minutes when the column height was 5 cm and the flow rate was 5 mL·min-1.Besides,the removal percentage of acenaphthene was about 70%by Triton X-100 enhanced biochar immobilized bacteria materials with a smaller particle size,which was higher than the larger diameter.Moreover,the mechanical strength and stability of the former were also better.As well,Triton X-100 enhanced biochar immobilized bacteria beads could be reused in continuous flow system. |
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