| The combustion of fossil fuels generates NOx pollutants which cause air pollution and acid rain. It is reported that the NOx pollutants in our country is seriously. The development of the technologies for NOx removal from flue gas is a problem we must to resolve. So it stares us. in the face to develop a new technology for NOx removal with the characteristics of low cost, completely reduction of NO and high removal efficiency.The newly proposed and adopted method in our work for NOx removal from flue gas, i.e. chemical absorption-bioelectric reduction integrated process, is deemed as a promising method. As part of this work, in this paper, the character and reduction ability of strain FR-2 and DN-2 in a bio-electrochemical reactor was studied, which was carried out under three different operations including electrochemical, biological and bio-electrochemical. The effect of initial Fe(Ⅲ)EDTA and NO2- concentration on the reduction was also investigated while the bacteria was in the section of being immobilized. As the section had been finished, the electrode with immobilized bacteria was detected, in order to prove the well-efficiency of the biological electrode as well as the current density control theory. The main experimental results were as follows:The effect of bio-electrochemistry was definitely better than single electrochemical or biological. It can raise up the efficiency by 30% while the react rate could be accumulated by 4 times compared with biology. During the section of immobilization, the reduction efficiency of Fe(Ⅲ)EDTA fell while the initial Fe(Ⅲ)EDTA concentration increased. And 40～160mg·L-1microbial inoculation seem to have the same effect on Fe(Ⅲ)EDTA reduction, while 320 mg·L-1 microbial inoculation was an inhibition concentration.As the immobilization has been finished, the reduction characteristic of the biological electrode was almost the same with or without microbial inoculation, which was an evident for the immobilization of bacteria. The SEM and the electrochemical characteristic of the electrode also supported the success of the immobilization of bacteria.DN-2 exhibited the same trend as FR-2. while the exist of the two bacteria, the reduction of Fe(Ⅲ)EDTA and NO2- would completed with each other. As a result, the reduction of NO2- was prior to Fe(Ⅲ)EDTA. The exist of NO2- would inhibit the reduction of Fe(Ⅲ)EDTA, just as some paper mentioned. |
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