Sulfide-driven nitrous oxide recovery during the mixotrophic denitrification process

作     者：Cong Yu Sen Qiao Jiti Zhou Cong Yu;Sen Qiao;Jiti Zhou

作者机构：Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of EducationChina)School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2023年第125卷第3期

页      面：443-452页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 0703[理学-化学] 

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)。 

主　　题：N_(2)O recovery N_(2)OR inhibition Cytochrome c Electron transfer capacity 

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.