nZVI materials loaded on biochar enhance the nitrate removal by denitrifying bacteria and the microbial metabolic characteristics
The coupling of nano-sized zero valent iron(nZVI)with microbes such as denitrifying bacteria has application potential in the field of nitrate remediation.However,several problems still remained during the applications,including the biological toxicity to microbes and easy aggregation of nZVI particles.Loading nZVI onto carrier materials can effectively alleviate these problems.Among various loading materials,nZVI materials loaded on biochar exhibit superior performance in promoting denitrification efficiency.However,the mechanism by which biochar loaded nZVI enhances denitrification by denitrifying bacteria is still unclear.This study synthesized representative nZVI materials loaded on biochar(BC/ZVI).Paracoccus denitrifican BNCC336866 was used as a model denitrification mode strain and a series of batch experiments was conducted to investigate the nitrate removal process in the presence of BC/ZVI.The results indicated that the reduction effect of ZVI can contribute 5.3％to 15.6％of the total nitrate removal.Compared to the control group that only dosed with denitrifying bacteria,the addition of BC,ZVI and BC/ZVI could enhance the denitrification efficiency to varying degrees.The untargeted metabolomics analysis confirmed that BC/ZVI predominantly enhanced the growth and proliferation of denitrifying bacteria cells by promoting transmembrane transport,substance metabolism and energy supply,protein and cell wall synthesis,etc.,thereby strengthening the overall denitrification capacity.
nZVI materials loaded on biochardenitrificationParacoccus denitrificanuntargeted metabolomics
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