Study On The Efficiency Of Bioelectrochemical System To Reduce And Degrade 2,4,6-trichlorophenol

As a typical persistent organic substance,chlorophenol is toxic and bioaccumulative,which poses a great threat to human health and ecological safety.Traditional anaerobic microorganisms can use hydrogen as an electron donor to reduce and dechlorinate chlorophenol,but there are problems such as long cycle and low efficiency.In recent years,the research of bioelectrochemical system to strengthen the decomposition of persistent organic matter has achieved rapid development.In this study,with 2,4,6-trichlorophenol as target pollutant,by building a sleeve type up-flow bioelectrochemical reaction system(SU-BES),the SU-BES The enhanced reduction and decomposition efficiency of 2,4,6-trichlorophenol optimizes the operating conditions of the system(voltage and hydraulic residence time),which is the enhanced decomposition of halogens represented by 2,4,6-trichlorophenol for bioelectrochemical systems Generation of organic pollutants provides a theoretical basis.First,this study first investigated the reductive decomposition efficiency of SU-BES to 2,4,6-trichlorophenol under the conditions of the continuous batch reaction.When the system is started,sodium lactate is added as a carbon source and a liquid electron donor,and the biological cathode is used as a solid electron donor.Studies have shown that SUBES can reduce 2,4,6-trichlorophenol to 4-chlorophenol as the final product.Moreover,when the applied voltage increased from 0 V to 0.8 V,the reductive decomposition rate of 2,4,6-trichlorophenol increased from 0.017 ?mol/L·d to 0.05 ?mol/L·d,indicating that 2,4,6-trichlorophenol There is a positive correlation between the decomposition rate of chlorophenol and the applied voltage.At the same time,the speed of sodium lactate fermentation also increases with increasing voltage.When the applied voltage rises from 0 V to 0.8 V,the amount of H2 generated gradually increases from 0.3 ?mol/L to 2.1 ?mol/L.The generation of excess H2 is caused by the hydrogen evolution caused by the increase of the applied voltage.Under different applied voltages,there is no significant difference in the amount of CH4 produced,which is around 2.3 mmol/L.Next,this study investigated the long-term operation effect and optimized conditions of SU-BES on the reductive decomposition of 2,4,6-trichlorophenol.When the hydraulic retention time(HRT)is 4 d and 2 d,the reduction dechlorination rate of 2,4,6-trichlorophenol at different voltages does not show a significant difference,because the HRT is too long,2,4,6-tri Chlorophenol is completely decomposed inside the reactor.When the HRT is shortened to 1 d,the voltage increases from 0.2 V to 0.8 V,and the decomposition rate of 2,4,6-trichlorophenol can be increased from 0.003 ?mol/L·d to 0.005 ?mol/L·d,indicating continuous operation In this case,the decomposition rate of 2,4,6-trichlorophenol is still positively correlated with the applied voltage.A higher voltage is accompanied by a higher amount of H2(2.63 ?mol/L,0.8 V).It is speculated that at higher voltages,hydrogen evolution at the cathode produces sufficient H2(electron donor),which activates the activity of dehalogenated respiratory bacteria,which ultimately leads to the enhanced reduction decomposition of 2,4,6-trichlorophenol.Subsequently,the performance of different types of reactors with 2,4,6-trichlorophenol decomposition performance was compared,and the advantages of this reactor for the reduction and decomposition efficiency of 2,4,6-trichlorophenol were found.The potential application potential of the reactor was briefly analyzed,discussed and prospected,revealing the potential and feasibility of this type of reactor for wastewater containing high concentration of chlorophenol.