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Wang Y, Qian L, Yang D, Gong Y, Yuan C, Hu Y, Gu H, Sun P, Wang S. Integration of hydrothermal liquefaction of Cyanophyta and supercritical water oxidation of its aqueous phase products: Biocrude production and nutrient removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169835. [PMID: 38190896 DOI: 10.1016/j.scitotenv.2023.169835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/23/2023] [Accepted: 12/30/2023] [Indexed: 01/10/2024]
Abstract
Cyanophyta has the potential to produce biocrude via hydrothermal liquefaction (HTL). However, aqueous phase products (APs), as by-products of HTL, pose a risk of eutrophication for the high levels of carbon, nitrogen, and phosphorus. Supercritical water oxidation (SCWO) can efficiently convert organics into small molecules, offering a technique for the harmless treatment of APs. Effects of holding time, pressure, and moisture content on the biocrude yields from isothermal HTL (300 °C) and fast HTL (salt bath temperature of 500 °C) were comprehensively investigated. Biocrude properties were characterized by elemental analysis, FT-IR and GC-MS. Subsequently, the APs obtained under the conditions producing the highest biocrude yield were subjected to SCWO at 550 °C with different oxidation coefficients (n) from 0 to 2. Removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP) were further explored. The results show that the highest biocrude yields from isothermal HTL and fast HTL were 24.2 wt% (300 °C, 1800 s, 25 MPa, and 80 wt% moisture content) and 21.9 wt% (500 °C, 40 s, 25 MPa, and 80 wt% moisture content), respectively. The biocrude primarily consisted of N-containing heterocyclic compounds, amides, and acids. SCWO effectively degraded the COD and TP in APs, while the NH3-N required further degradation. At n = 2, the highest removal rates of COD, NH3-N and TP were 98.5 %, 22.6 % and 89.1 %, respectively.
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Affiliation(s)
- Yanxin Wang
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Lili Qian
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
| | - Derui Yang
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yanmeng Gong
- Jiangsu Provincial Academy of Environmental Science, Jiangsu Province Key Laboratory of Environmental Engineering, Nanjing, Jiangsu 210036, China
| | - Chuan Yuan
- School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yamin Hu
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Heng Gu
- School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Panpan Sun
- College of Mechanical & Electrical Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China
| | - Shuang Wang
- School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
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Li J, Pinkard BR, Wang S, Novosselov IV. Review: Hydrothermal treatment of per- and polyfluoroalkyl substances (PFAS). CHEMOSPHERE 2022; 307:135888. [PMID: 35931254 DOI: 10.1016/j.chemosphere.2022.135888] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/14/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
PER: and polyfluoroalkyl substances (PFAS) are a concerning and unique class of environmentally persistent contaminants with biotoxic effects. Decades of PFAS discharge into water and soil resulted in PFAS bioaccumulation in plants, animals, and humans. PFAS are very stable, and their treatment has become a global environmental challenge. Significant efforts have been made to achieve efficient and complete PFAS mineralization using existing and emerging technologies. Hydrothermal treatments in subcritical and supercritical water have emerged as promising end-of-life PFAS destruction technologies, attracting the attention of scholars, industry, and key stakeholders. This paper reviews the state-of-the-art research on the behavior of PFAS, PFAS precursors, PFAS alternatives, and PFAS-containing waste in hydrothermal processes, including the destruction and defluorination efficiency, the proposed reaction mechanisms, and the environmental impact of these treatments. Scientific literature shows that >99% degradation and >60% defluorination of PFAS can be achieved through subcritical and supercritical water processing. The limitations of current research are evaluated, special considerations are given to the challenges of technology maturation and scale-up from laboratory studies to large-scale industrial application, and potential future technological developments are proposed.
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Affiliation(s)
- Jianna Li
- University of Washington, Mechanical Engineering Department, Seattle, WA 98195, USA; Key Laboratory of Thermo-Fluid Science and Engineering of MOE, School of Energy and Power Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049, China
| | - Brian R Pinkard
- University of Washington, Mechanical Engineering Department, Seattle, WA 98195, USA; Aquagga, Inc., Tacoma, WA 98421, USA
| | - Shuzhong Wang
- Key Laboratory of Thermo-Fluid Science and Engineering of MOE, School of Energy and Power Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049, China
| | - Igor V Novosselov
- University of Washington, Mechanical Engineering Department, Seattle, WA 98195, USA.
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A Review of Hybrid Process Development Based on Electrochemical and Advanced Oxidation Processes for the Treatment of Industrial Wastewater. INTERNATIONAL JOURNAL OF CHEMICAL ENGINEERING 2022. [DOI: 10.1155/2022/1105376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Nowadays, increased human activity, industrialization, and urbanization result in the production of enormous quantities of wastewater. Generally, physicochemical and biological methods are employed to treat industrial effluent and wastewater and have demonstrated high efficacy in removing pollutants. However, some industrial effluent and wastewater contain contaminants that are extremely difficult to remove using standard physicochemical and biological processes. Previously, electrochemical and hybrid advanced oxidation processes (AOP) were considered a viable and promising alternative for achieving an adequate effluent treatment strategy in such instances. These processes rely on the production of hydroxyl radicals, which are highly reactive oxidants that efficiently break down contaminants found in wastewater and industrial effluent. This review focuses on the removal of contaminants from industrial effluents and wastewater through the integration of electrochemical and advanced oxidation techniques. These processes include electrooxidation, electrocoagulation/electroflocculation, electroflotation, photo-Fenton, ozone-photo-Fenton, sono-photo-Fenton, photo-electro-Fenton, ozone/electrocoagulation, sono-electrocoagulation, and peroxi/photo/electrocoagulation. The data acquired from over 150 published articles, most of which were laboratory experiments, demonstrated that the hybrid process is more effective in removing contaminants from industrial effluent and wastewater than standalone processes.
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