An Innovative in Situ Monitoring of Sulfate Reduction within a Wastewater Biofilm by H2S and SO42− Microsensors

International Journal of Environmental Research and Public Health

Ning Ding¹  Xun Liu²  Hong Liu³ 

[1] Key Laboratory of Cleaner Production and Comprehensive Utilization of Resources, China National Light Industry, Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing 100048, China;School of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215000, China;School of Environmental Science and Engineering, Jiangsu Key Laboratory of Environmental Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China;

关键词: microelectrode;    wastewater;    biofilm;    sulfate reduction;    activity;   

DOI  :  10.3390/ijerph17062023

来源: DOAJ

【 摘 要 】

Microelectrodes can be used to obtain chemical profiles within biofilm microenvironments. For example, sulfate (SO₄²⁻) and hydrogen sulfide (H₂S) microelectrodes can be used to study sulfate reduction activity in this context. However, there is no SO₄²⁻ microelectrode available for studying sulfate reduction in biofilms. In this study, SO₄²⁻ and H₂S microelectrodes were fabricated and applied in the measurement of a wastewater membrane-aerated biofilm (MAB) to investigate the in situ sulfate reduction activity. Both the SO₄²⁻ and H₂S microelectrodes with a tip diameter of around 20 micrometers were successfully developed and displayed satisfying selectivity to SO₄²⁻ and H₂S, respectively. The Nernstian slopes of calibration curves of the fabricated SO₄²⁻ electrodes were close to −28.1 mV/decade, and the R² values were greater than 98%. Within the selected concentration range from 10⁻⁵ M (0.96 mg/L) to 10⁻² M (960 mg/L), the response of the SO₄²⁻ microelectrode was log-linearly related to its concentration. The successfully fabricated SO₄²⁻ microelectrode was combined with the existing H₂S microelectrode and applied on an environmental wastewater biofilm sample to investigate the sulfate reduction activity within it. The H₂S and SO₄²⁻ microelectrodes showed stable responses and good performance, and the decrease of SO₄²⁻ with an accompanying increased of H₂S within the biofilm indicated the in situ sulfate reduction activity. The application of combined SO₄²⁻ and H₂S microelectrodes in wastewater biofilms could amend the current understanding of sulfate reduction and sulfur oxidation within environmental biofilms based on only H₂S microelectrodes.

【 授权许可】

Unknown