Study On The Pollution Control Of Nigrosine And Phenanthrene By Strains Under The Control Of Mineral Particles

Nigrosine and phenanthrene are common beneficiation reagents and polycyclic aromatic hydrocarbon pollutants.Because the harm to human health and the environment cannot be ignored,their treatment cannot be delayed.At present,the microbial treatment of nigrosine and phenanthrene has become a research hotspot at home and abroad because of its green,cheap,and low-prone to secondary pollution.In this paper,we screened strains to treat nigrosine,using non-metallic minerals as carriers,and using immobilized microorganisms to treat nigrosine and phenanthrene pollution.Burkholderia,Enterobacter and the purchased Pseudomonas aeruginosa were screened out from the activated sludge of the sewage treatment plant of Southwest University of Science and Technology as the experimental strains in this paper.Through the growth characteristics of the strain,the changes in the concentration of nigrosine and phenanthrene in solution,and the determination of the products in the solution,the influencing factors and metabolic pathways of the strain's treatment of nigrosine and phenanthrene were explored.The results show that the amount of microorganisms added can promote the degradation rate.Pseudomonas aeruginosa is more suitable for growth in neutral conditions(p H 6.5-7.5),and B-1 and B-4 bacteria are in a weak acid environment(p H 5.5-6.5)The degradation rate of p-Nigrosine is obviously faster than in an alkaline environment.Through the determination of gas mass spectrometer,it was determined that the B-4 strain produced aniline during the treatment of nigrosine.For the selection of carrier materials,the results show that: CTMAB modified zeolite adsorption of phenanthrene and Langmuir adsorption isotherms have a good fit(RL=0.994).In this experiment,the value of 1/n of the adsorbent is equal to 0.45.Monomolecular layer adsorption is more likely to occur on zeolite;the results of adsorption of nigrosine by 1#particles have a better fit in the Freundlich model(RF=0.946>RL=0.926),and the 1/n value of the adsorbent in this experiment is equal to 0.851,the theoretical maximum adsorption capacity qm=50mg/g,the adsorption reaction of nigrosine on the 1# particles is easier.Through Fourier infrared measurement of modified zeolite before and after adsorption,it is found that after adsorption,the modified zeolite produces a series of new peaks at3838.74cm-1 and 3736.38cm-1,which are due to the C—H groups on phenanthrene.The peak intensity at 3445 cm-1 increases significantly,which may be related to functional groups such as-OH and N-H.After the strain and carrier are optimized and determined,an immobilized microorganism is made.The results showed that the initial p H value was above 9 and the concentration of nigrosine was 300 mg/L.After 16 days of treatment with immobilized microorganisms,the removal rate of nigrosine could reach 67.44%.After immobilized Pseudomonas aeruginosa treated phenanthrene in the solution for 160 h,the removal rate reached 86.92%.When the initial concentration of phenanthrene in the soil was 20 mg/kg,the removal rate was 18.13%after adding Pseudomonas aeruginosa for 50 days,and the removal rate was 27.85% after adding zeolite-Pseudomonas aeruginosa for 50 days.