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Wang R, Cao J, Zhu W, Lv Y. Integration of pre-precipitation optimizing performance of culture medium prepared from salvaged cyanobacterial slurry. Chemosphere 2023; 316:137805. [PMID: 36632957 DOI: 10.1016/j.chemosphere.2023.137805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/06/2022] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Cyanobacterial slurry is a waste biomass produced in the remediation of eutrophic lakes; it is obtained in large volume and is difficult to treat, but it has the potential to be used as raw material for culture medium for oil-producing microalgae. In this study, three kinds of oil-producing microalgae were tested, including Chlorella vulgaris, Scenedesmus obliquus, and Nannochloropsis oculate. On the basis of the medium preparation method "hydrothermal oxidation + ultrafiltration," the pre-precipitation phenomenon induced by pH adjustment was implemented to modify the culture medium and improve its performance. Ammonia nitrogen and macromolecules (mainly humic substances) were found to possibly have a joint-influence mechanism upon microalgae. Pre-precipitation changed the nitrogen species distribution in the medium and lowered the concentration of macromolecules, which improved the ability of microalgae to use different forms of nitrogen. This promoted the growth of, and oil production by, the microalgae.
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Affiliation(s)
- Ruochen Wang
- College of Environment, Hohai University, Nanjing, 210098, China; Center for Taihu Basin, Institute of Water Science and Technology, Hohai University, Nanjing, 211111, China
| | - Jun Cao
- College of Environment, Hohai University, Nanjing, 210098, China; Center for Taihu Basin, Institute of Water Science and Technology, Hohai University, Nanjing, 211111, China; National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Hohai University, Nanjing, 211111, China
| | - Wei Zhu
- College of Environment, Hohai University, Nanjing, 210098, China; Center for Taihu Basin, Institute of Water Science and Technology, Hohai University, Nanjing, 211111, China.
| | - Yi Lv
- College of Environment, Hohai University, Nanjing, 210098, China; Center for Taihu Basin, Institute of Water Science and Technology, Hohai University, Nanjing, 211111, China
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Liu G, Geng J, Li Y, Li H, Wang M, Chen D, Ma N, Wang H. Improved stress corrosion cracking resistance of in-situ TiB 2/7050Al composite by pre-precipitation treatment. Micron 2021; 145:103056. [PMID: 33740567 DOI: 10.1016/j.micron.2021.103056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 11/27/2022]
Abstract
A two-step aging treatment (50 L P, a peak aging following 50 ℃ pre-precipitation) has been investigated for the in-situ TiB2/7050Al composite. The 50 L P composite has the comparable mechanical properties to the composite at peak-aged (T6) state, and even better stress corrosion cracking resistance over the composite with the retrogression and re-aging (RRA) treatment. In detail, the different aging conditions lead to different precipitate morphologies and grain boundary microchemistries. According to the microstructure characteristics in the Al matrix, the 50 L P composite has considerably increased grain boundary precipitate interspace in comparison with the T6 composite, since the lower aging temperature should result in the reduced grain boundary precipitate number. Furthermore, the 50 L P composite has more Cu content in the grain boundary precipitate and reduced precipitate free zone width over the RRA composite, indicating the improved stress corrosion cracking resistance. For the reinforcement, the TiB2 particles should slightly aggravate the stress corrosion cracking susceptibility, since the grain boundary precipitates are still the preferential corrosion sites due to their lower corrosion potentials.
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Affiliation(s)
- Gen Liu
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiwei Geng
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yugang Li
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hongping Li
- Shanghai Aircraft Design and Research Institute, Shanghai, 201203, China
| | - Mingliang Wang
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Dong Chen
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China; Anhui Provincial Engineering Research Center of Aluminum Matrix, Huaibei, 235000, China.
| | - Naiheng Ma
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Anhui Provincial Engineering Research Center of Aluminum Matrix, Huaibei, 235000, China
| | - Haowei Wang
- State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
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