1
|
Xiao Y, Feng J, Zhang L, Yang Y, Zhou X, Xu D, Gong M, Yin H, Yuan S. Purification of dredged water by magnetic coagulation: Response surface optimization and dissolved organic matter removal characteristics. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2024; 96:e10996. [PMID: 38369707 DOI: 10.1002/wer.10996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/07/2024] [Accepted: 01/25/2024] [Indexed: 02/20/2024]
Abstract
In the present study, magnetic coagulation was used to treat dredged water and the response surface method was used to optimize process parameters. The dissolved organic matter (DOM) removal characteristics were characterized by three-dimensional fluorescence spectrometry and ultra-high resolution mass spectrometry. During the magnetic coagulation process, the suspended solids (SS) removal rate increased initially and then decreased under conditions of increasing magnetic powder dosage and stirring rate. After magnetic coagulation and precipitation for 20 min, the contents of SS, ammonia nitrogen, chemical oxygen demand, and total phosphorus in the treated dredged water met the requirements of the discharge standard (GB8978-1996, China). Three-dimensional fluorescence results showed that magnetic coagulation selectively removed fulvic acids and humic acid substances. After magnetic coagulation with precipitation for 10 min and 20 min, the total relative content of lignins, tannins, proteins, lipids, aminosugars, unsaturated hydrocarbons, condensed aromatic structures, and carbohydrates decreased by 26.3% and 39.4%, respectively. After magnetic coagulation, the distribution range of small molecule DOM shifted to the low H/C and high O/C regions. This study provides a novel perspective for studies on the removal of DOM in dredged water by magnetic coagulation. PRACTITIONER POINTS: SS and DOM removal were significantly enhanced by the use of magnetic coagulation. SS removal efficiency was affected by stirring rate and magnetic powder dosage. Magnetic coagulation selectively removed fulvic acids and humic acid substances. DOM molecule shifted to low H/C and high O/C regions after magnetic coagulation.
Collapse
Affiliation(s)
- Yuanting Xiao
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| | - Jingwei Feng
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| | - Liu Zhang
- Anhui Provincial Academy of Eco-Environmental Science Research, Hefei, China
| | - Yulin Yang
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| | - Xuyang Zhou
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| | - Deqian Xu
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| | - Miao Gong
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| | - Hao Yin
- CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China
- Mass Spectrometry Lab, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, China
| | - Shoujun Yuan
- Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, China
| |
Collapse
|
2
|
Li J, Wang T, Liang E. Carbon and hydrogen isotopic evidence for atrazine degradation by electro-activated persulfate: Radical contributions and comparisons with heat-activated persulfate. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122892. [PMID: 37952922 DOI: 10.1016/j.envpol.2023.122892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/01/2023] [Accepted: 11/05/2023] [Indexed: 11/14/2023]
Abstract
The activation ways of persulfate (PS) were dominate for pollutant degradation and energy consumption. For the first time, this research compared electro-activated PS and heat-activated PS from the perspective of isotope fractionation, in order to "fingerprinted" and precisely interpretate reaction contributions and degradation pathways. As results, PS can be electrochemically activated with atrazine (ATZ) removal rates of 84.8% and 88.8% at pH 4 and 7. The two-dimensional isotope plots (ɅC/H) values were 6.20 at pH 4 and 7.46 at pH 7, rather different from that of SO4·- -dominated process with ɅC/H value of -4.80 at pH 4 and -23.0 at pH 7, suggesting the weak contribution of SO4·-. ATZ degradation by electro-activated PS was controlled by direct electron transfer (DET) and ·OH radical, and ·OHPS (derived from PS activation) played the crucial role with contributing rate of 63.2%-69.1%, while DET and ·OHBDD (derived from electrolysis of H2O) contributed to 4.5-7.9% and 23.0%-30.8%, respectively. This was different from heat activation of PS, of which the latter was dominated by SO4·- with contributions of 83.9%-100%. The discrepant dominating reactive oxygen species should be responsible for their different degradation capabilities and pathways. This research provided isotopic interpretations for differences of PS activation mode, and further efforts can be made to realize the selective degradation by enhancing the specific reaction process.
Collapse
Affiliation(s)
- Jie Li
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China; Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Ting Wang
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China.
| | - Enhang Liang
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| |
Collapse
|