An Innovative in Situ Monitoring of Sulfate Reduction within a Wastewater Biofilm by H 2 S and SO 4 2? Microsensors

Hong Liu, Xun Liu and Ning Ding
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Hong Liu: School of Environmental Science and Engineering, Jiangsu Key Laboratory of Environmental Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China
Xun Liu: School of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215000, China
Ning Ding: 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

IJERPH, 2020, vol. 17, issue 6, 1-11

Abstract: Microelectrodes can be used to obtain chemical profiles within biofilm microenvironments. For example, sulfate (SO 4 2− ) and hydrogen sulfide (H 2 S) microelectrodes can be used to study sulfate reduction activity in this context. However, there is no SO 4 2− microelectrode available for studying sulfate reduction in biofilms. In this study, SO 4 2− and H 2 S 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 SO 4 2− and H 2 S microelectrodes with a tip diameter of around 20 micrometers were successfully developed and displayed satisfying selectivity to SO 4 2 − and H 2 S, respectively. The Nernstian slopes of calibration curves of the fabricated SO 4 2− electrodes were close to −28.1 mV/decade, and the R 2 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 SO 4 2− microelectrode was log-linearly related to its concentration. The successfully fabricated SO 4 2− microelectrode was combined with the existing H 2 S microelectrode and applied on an environmental wastewater biofilm sample to investigate the sulfate reduction activity within it. The H 2 S and SO 4 2− microelectrodes showed stable responses and good performance, and the decrease of SO 4 2− with an accompanying increased of H 2 S within the biofilm indicated the in situ sulfate reduction activity. The application of combined SO 4 2− and H 2 S microelectrodes in wastewater biofilms could amend the current understanding of sulfate reduction and sulfur oxidation within environmental biofilms based on only H 2 S microelectrodes.

Keywords: microelectrode; wastewater; biofilm; sulfate reduction; activity (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
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