{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:45:09Z","timestamp":1787028309195,"version":"build-2736575974"},"reference-count":36,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2020,3,19]],"date-time":"2020-03-19T00:00:00Z","timestamp":1584576000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51708381"],"award-info":[{"award-number":["51708381"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004608","name":"Natural Science Foundation of Jiangsu Province","doi-asserted-by":"publisher","award":["BK20181466"],"award-info":[{"award-number":["BK20181466"]}],"id":[{"id":"10.13039\/501100004608","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Open Research Fund Program of Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry","award":["CP-2018-YB1"],"award-info":[{"award-number":["CP-2018-YB1"]}]},{"name":"People's Livelihood Projects of Suzhou Science and Technology Bureau","award":["SS2019028"],"award-info":[{"award-number":["SS2019028"]}]},{"name":"Environmental Protection Project from Suzhou Ecological and Environmental Protection Bureau","award":["B201903"],"award-info":[{"award-number":["B201903"]}]},{"name":"Entrepreneurship and Innovation Project from Jiangsu Province","award":["491911202"],"award-info":[{"award-number":["491911202"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Microelectrodes can be used to obtain chemical profiles within biofilm microenvironments. For example, sulfate (SO42\u2212) and hydrogen sulfide (H2S) microelectrodes can be used to study sulfate reduction activity in this context. However, there is no SO42\u2212 microelectrode available for studying sulfate reduction in biofilms. In this study, SO42\u2212 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\u2212 and H2S microelectrodes with a tip diameter of around 20 micrometers were successfully developed and displayed satisfying selectivity to SO42\u2212 and H2S, respectively. The Nernstian slopes of calibration curves of the fabricated SO42\u2212 electrodes were close to \u221228.1 mV\/decade, and the R2 values were greater than 98%. Within the selected concentration range from 10\u22125 M (0.96 mg\/L) to 10\u22122 M (960 mg\/L), the response of the SO42\u2212 microelectrode was log-linearly related to its concentration. The successfully fabricated SO42\u2212 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\u2212 microelectrodes showed stable responses and good performance, and the decrease of SO42\u2212 with an accompanying increased of H2S within the biofilm indicated the in situ sulfate reduction activity. The application of combined SO42\u2212 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.<\/jats:p>","DOI":"10.3390\/ijerph17062023","type":"journal-article","created":{"date-parts":[[2020,3,19]],"date-time":"2020-03-19T10:01:35Z","timestamp":1584612095000},"page":"2023","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["An Innovative in Situ Monitoring of Sulfate Reduction within a Wastewater Biofilm by H2S and SO42\u2212 Microsensors"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7674-6613","authenticated-orcid":false,"given":"Hong","family":"Liu","sequence":"first","affiliation":[{"name":"School of Environmental Science and Engineering, Jiangsu Key Laboratory of Environmental Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xun","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ning","family":"Ding","sequence":"additional","affiliation":[{"name":"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"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"16220","DOI":"10.1080\/19443994.2015.1077739","article-title":"Characterization, structure, and function of extracellular polymeric substances (EPS) of microbial biofilm in biological wastewater treatment systems: A review","volume":"57","author":"Salama","year":"2016","journal-title":"Desalin. 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