We propose a novel sulfide-driven process to recover N_(2)O during the traditional denitrification process.The optimum initial sulfide concentration was 120 mg/L,and the N_(2)O percentage in the gaseous products (N_(2...We propose a novel sulfide-driven process to recover N_(2)O during the traditional denitrification process.The optimum initial sulfide concentration was 120 mg/L,and the N_(2)O percentage in the gaseous products (N_(2)O+N_(2)) was up to 82.9%.Moreover,sulfide involved in denitrification processes could substitute for organic carbon as an electron donor,e.g.,1g sulfide was equivalent to 0.5-2 g COD when sulfide was oxidized to sulfur and sulfate.The accumulation of N_(2)O was mainly due to the inhibiting effect of sulfide on nitrous oxide reductase (N_(2)OR),which was induced by the supply insufficiency of electrons from cytochrome c (cyt c) to N_(2)OR.When the initial sulfide concentration was 120 mg/L,the N_(2)OR activity was only 36.8%of its original level.According to the results of cyclic voltammetry,circular dichroism spectra and fluorescence spectra,significant changes in the conformations and protein structures of cyt c were caused by sulfide,and cyt c completely lost its electron transport capacity.This study provides a new concept for N_(2)O recovery driven by sulfide in the denitrification process.In addition,the findings regarding the mechanism of the inhibition of N_(2)OR activity have important implications both for reducing emissions of N_(2)O and recovering N_(2)O in the sulfide-driven denitrification process.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51878111)the National Key Research and Development Project (No. 2019YFA0705804)+1 种基金the Natural Science Foundation of Jiangsu Province (No. BK20181224)the Liaoning Revitalization Talents Program (No. XLYC1807067)。
文摘We propose a novel sulfide-driven process to recover N_(2)O during the traditional denitrification process.The optimum initial sulfide concentration was 120 mg/L,and the N_(2)O percentage in the gaseous products (N_(2)O+N_(2)) was up to 82.9%.Moreover,sulfide involved in denitrification processes could substitute for organic carbon as an electron donor,e.g.,1g sulfide was equivalent to 0.5-2 g COD when sulfide was oxidized to sulfur and sulfate.The accumulation of N_(2)O was mainly due to the inhibiting effect of sulfide on nitrous oxide reductase (N_(2)OR),which was induced by the supply insufficiency of electrons from cytochrome c (cyt c) to N_(2)OR.When the initial sulfide concentration was 120 mg/L,the N_(2)OR activity was only 36.8%of its original level.According to the results of cyclic voltammetry,circular dichroism spectra and fluorescence spectra,significant changes in the conformations and protein structures of cyt c were caused by sulfide,and cyt c completely lost its electron transport capacity.This study provides a new concept for N_(2)O recovery driven by sulfide in the denitrification process.In addition,the findings regarding the mechanism of the inhibition of N_(2)OR activity have important implications both for reducing emissions of N_(2)O and recovering N_(2)O in the sulfide-driven denitrification process.
