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Yang X, Qin X, Xie J, Li X, Xu H, Zhao Y. Study on the effect of Cr(VI) removal by stimulating indigenous microorganisms using molasses. CHEMOSPHERE 2022; 308:136229. [PMID: 36041530 DOI: 10.1016/j.chemosphere.2022.136229] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/05/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Molasses have a prominent effect on the bioremediation of Cr(VI) contaminated groundwater. However, its reaction mechanism is not detailed. In this paper, the removal of Cr(VI) with different carbon sources was compared to explore the effect and mechanism of the molasses. The addition of molasses can completely remove 25 mg/L Cr(VI), while the removal efficiency by glucose or emulsified vegetable oil was only 20%. Molasses could rapidly stimulate the reduction of Cr(VI) by indigenous microorganisms and weakened the toxicity on bacteria. The average removal rate of Cr(VI) was 0.42 mg/L·h, 10 times that of glucose system. Compared with glucose, molasses can remediate Cr(VI) at a higher concentration (50 mg/L), and the carbohydrate acted as microbial nutrients. Direct and indirect reduction acted together, the Fe(II) content in the aquifer medium increased from 1.7% to 4.7%. The addition of molasses extract into glucose system could increased the removal rate of Cr(VI) by 2-3 times, and the ions of molasses had no significant effect on the reduction. Excitation emission matrix fluorescence spectra and electrochemical analysis proved that the molasses contained humic acid-like substances, which had the ability of electron shuttle and improved the reduction rate of Cr(VI). In the process of bioreduction, the composition of molasses changed and the electron transport capacity increased from 104.2 to 446.5 μmol/(g C), but these substances could not be used as electron transport media to continuously enhance the reduction effect. This study is of great significance to fully understand the role and application of molasses.
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Affiliation(s)
- Xinru Yang
- Key Laboratory of Groundwater Resources and Environment of Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun, 130021, China
| | - Xueming Qin
- Key Laboratory of Groundwater Resources and Environment of Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun, 130021, China
| | - Jiayin Xie
- Key Laboratory of Groundwater Resources and Environment of Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun, 130021, China
| | - Xiaoyu Li
- Key Laboratory of Groundwater Resources and Environment of Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun, 130021, China
| | - Huichao Xu
- Key Laboratory of Groundwater Resources and Environment of Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun, 130021, China
| | - Yongsheng Zhao
- Key Laboratory of Groundwater Resources and Environment of Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun, 130021, China.
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