The efficiency of generating electrical current in microbial fuel cells (MFC) may decrease due to overvoltage losses at the cathode electrode. To eliminate this problem, cathodes based on materials containing catalysts in their composition are used in the MFC technology, which provide for the intense removal of excess electrons by oxygen. The most effective catalyst in this regard is platinum. However, the use of this metal at times increases the cost of technology. In this regard, the actual aspect is the search for new, cheaper, promising catalysts for cathodic processes. There is a number of data indicating the possibility of using microorganisms as biological catalysts for cathodic processes in MFC . The purpose of this work is to evaluate the performance of MFC with biocathodes based on nitrate-reducing strains of Pseudomonas aeruginosa 3-SV and 20-SV, isolated from wastewater of the Angarsk Petrochemical Plant (APP).
The study of the processes of generation of electric current was carried out using models of MFC, designed in the Institute of Biology of ISU. The design of such an MFC, methods for its processing and removal of electrical parameters are described in . The culture of Micrococcus luteus strain 1-I was used as an anode bioagent. This strain was isolated from activated sludge from APP treatment facilities (Russia, Angarsk) E. Yu. Konovalova. The cathode bioagents were denitrifying bacteria Pseudomonas aeruginosa strain 3-SV and Pseudomonas aeruginosa strain 20-SV. These cultures were isolated from wastewater APP (Russia, Angarsk) O. F. Vyatchina. The main working medium in MFC was model wastewater. Substrate for microorganisms in the anode was peptone (0.5 g / l). NO32- ions (in the form of KNO3) were introduced into the catholyte. Their concentration in the catholyte of MFC was 150 mg / l. The concentration of nitrate ions was determined by the photometric method with salicylic acid .
The electrical indices of MFC with biocathodes based on the strains of P. aeruginosa 20-SV and P. aeruginosa 3-SV were significantly higher than those of MFC with nitrate cathodes without adding microorganisms to them. At the same time, MFC with a biocathode with a strain of P. aeruginosa 20-SV turned out to be more effective than MFC with a biocathode based on P. aeruginosa 3-SV, as by the value of generated electricity (voltage and current strength of MFC with P. aeruginosa 20-SV – 478 ± 12 mV and 1361 ± 133 μA, with P. aeruginosa 3-SV – 380 ± 10 mV and 1011 ± 10 μA, respectively), and according to the degree of elimination of nitrate (from 147.96 ± 9.77 to 0.00 mg / dm3 in the MFC biocathode with P. aeruginosa 20-SV) and from 141.59 ± 11.82 to 54.66 ± 2.39 mg / l in the biocathode with P. aeruginosa 3-SV for 96 hours of the experiment). Thus, the conducted studies allow us to recommend the culture of P. aeruginosa 20-SV, isolated from wastewater of the APP, for the production of the MFC biocathode with its simultaneous use for the purification of wastewater from nitrates.
The work was carried out with the financial support of RFBR grant 18-48-030019 "Study of the interaction of individual strains and microbial associations possessing electrogenic activity in MFC, with pollutants of domestic wastewater and development of recommendations on intensification of their treatment". The authors are grateful for participating in the experimental part of the works of E. V. Azarenko.
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|Position of speaker||доцент|
|Affiliation of speaker||Иркутский государственный университет|
|Publication||Journal of Cleaner Production|