The Research Of Fungi On Flue Gas Purification And NO_x Removal In Packed Towers By Bio-film Method

SO2 and NOx emitted by industry are seriously polluting gas.In the process of using the biological method to purify flue gas,the denitrification efficiency that can't meet technical requirements is not high.At home and abroad,there was much study of bacterial purifying NO and NOx,however the function of fungi was poorly studied.In order to improve the removal efficiency of NO and NOx,the fungi from Denitrification tower biofilm were separated,purified and identified.The nitrification and denitrification characteristics of three fungi were studied by shaking flasks experiment.We put the expanding culture of three pure strains into Denitrifying tower to study the efficiency of removing NOx.And the community structure of the fungi in Denitrification tower was analyzed by high-throughput sequencing.The results showed that the 1LNL strain isolated and purified from Denitrification biofilm was identified as Trichodema asperellum,the 3LNB strain was identified as Fusarium solani,and the 5LNS strain was identified as Neurospora sitophila.The results of high-throughput sequencing analysis showed that three fungi isolated and identified are from Denitrification tower.On the other hand,it was found that there are abundant diversity of fungal communities in the flue gas Denitrification tower.Up to 10.01 g/L of NO3--N,the denitrifying rate of bacteria control group was 5.6%with nitrogen removal 0.56 g/L.But the denitrification rate of Fusarium solani was 15.1%with nitrogen removal 1.51 g/L for 10 days,whose nitrification capacity is 2.7 times of the bacteria,that proved Fusarium solani having strong denitrification function.The high-throughput analysis results are on the genus level reading 317 with relative abundance 0.73%.Trichoderma asperellum can directly oxidize NO2-into NO3-.10 days later,the nitration rate of bacteria control group was 31.5%and the nitrification rate of the blank control group was 8.4%,the rate of nitrification of Trichoderma asperellum was 25.0%,which proved Trichoderma asperellum having nitrification function.The high-throughput analysis results are on the genus level reading 24 with relative abundance 0.05%.Neither the nitrification efficiency nor the denitrification efficiency of Neurospora sitophila were not strong,but the high-throughput analysis results on the genus level were high reading 1117 wirh relative abundance 2.56%.Its role and mechanism in Denitrification tower need further study.We put the expanding culture of the three pure strains each 400mL into the denitrification column,the removal rate of NO and NOx was increased by 5.41%and 5.32%respectively on average.The results showed that the removal efficiency of NO and NOx could be improved by the addition of three strains of fungi.This paper discovered and systematically studied the important role of fungi in Denitrification tower,discussed its part mechanism,and laid the experimental and theoretical basis for promoting the biological process of purifying flue gas.The role of fungi should be paid more attention to and the research should be carried out continuously.