摘要
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.
基金
financially supported by the National Natural Science Foundation of China (No. 51878111)
the National Key Research and Development Project (No. 2019YFA0705804)
the Natural Science Foundation of Jiangsu Province (No. BK20181224)
the Liaoning Revitalization Talents Program (No. XLYC1807067)。
作者简介
Corresponding author:Sen Qiao.E-mail:qscyj@mail.dlut.edu.cn。
