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Kim DS, Lee DK. Low-temperature catalytic aqueous phase oxidation of microcystin-LR with iron-doped TiO 2 pillared clay catalysts. ENVIRONMENTAL TECHNOLOGY 2021; 42:3546-3553. [PMID: 32100642 DOI: 10.1080/09593330.2020.1734097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/19/2020] [Indexed: 06/10/2023]
Abstract
TiO2-PILCs and iron-doped TiO2-PILCs were employed in order to destroy toxic microcystin-LR in the presence of H2O2 under the UV light. While less than 5% of the initial microcystin-LR and TOC disappeared in 240 min with the TiO2-PILCs, almost complete conversion of microcystin-LR could be achieved in 180 min on the 10 wt% iron-doped TiO2-PILC-A. On the exterior surface of the iron-doped TiO2-PILCs were mainly located iron particles which had nano-sized diameter and Fe2+/Fe3+ cations together. Through Fenton-type oxidation on iron particles with H2O2, the big microcystin-LR molecules were converted primarily into smaller intermediate organic molecules of hydrocarbons, carboxylic acids and organic amines. The smaller intermediate molecules were believed to be diffused into the pores of the iron-doped TiO2-PILCs and to be further mineralized into CO2 and H2O through the action of photocatalysis on the TiO2 pillars. However, complete conversion of TOC could not be obtained due to the iron particle deactivation. XPS, TPO and TEM studies showed the continuous accumulation of carbonaceous materials onto the surface of iron particles.
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Affiliation(s)
- Dul-Sun Kim
- Department of Chemical Engineering, Gyeongsang National University, Jinju-si, Korea
| | - Dong-Keun Lee
- Department of Chemical Engineering, Gyeongsang National University, Jinju-si, Korea
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He X, Wang A, Wu P, Tang S, Zhang Y, Li L, Ding P. Photocatalytic degradation of microcystin-LR by modified TiO 2 photocatalysis: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140694. [PMID: 32673915 DOI: 10.1016/j.scitotenv.2020.140694] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 05/23/2023]
Abstract
Microcystin-LR (MC-LR), the most toxic and commonly encountered cyanotoxin, is produced by harmful cyanobacterial blooms and potentially threatens human and ecosystems health. Titanium dioxide (TiO2) photocatalysis is attracting growing attention and has been considered as an efficient, environmentally friendly and promising solution to eliminate MC-LR in the aquatic ecosystems. Over recent decades, scientific efforts have been directed towards the understanding of fundamentals, modification strategies, and application potentials of TiO2 photocatalysis in degrading MC-LR. In this article, recent reports have been reviewed and progress has been summarized in the development of heterogeneous TiO2-based photocatalysts for MC-LR photodegradation under visible, UV, or solar light. The proposed photocatalytic principles of TiO2 and destruction of MC-LR have been thoroughly discussed. Specifically, some main modification methods for improving the drawbacks and performance of TiO2 nanoparticle were highlighted, including element doping, semiconductor coupling, immobilization, floatability amelioration and magnetic separation. Moreover, the performance evaluation metrics quantum yield (QY) and figure of merit (FOM) were used to compare different photocatalysts in MC-LR degradation. The best performance was seen in N-TiO2 with QY and FOM values of 2.20E-07 molecules/photon and 1.00E-11 mol·L/(g·J·h). N-TiO2 or N-TiO2-based materials may be excellent options for photocatalyst design in terms of MC-LR degradation. Finally, a summary of the remaining challenges and perspectives on new tendencies in this exciting frontier and still an emerging area of research were addressed accordingly. Overall, the present review will offer a deep insight for understanding the photodegradation of MC-LR with modified TiO2 to further inspire researchers that work in associated fields.
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Affiliation(s)
- Xinghou He
- Central South University Xiangya School of Public Health, Changsha, Hunan 410078, China
| | - Anzhi Wang
- University School of South China Hengyang Medical School, Hengyang, Hunan 421001, China
| | - Pian Wu
- Central South University Xiangya School of Public Health, Changsha, Hunan 410078, China
| | - Shibiao Tang
- Central South University School of Minerals Processing and Bioengineering, Changsha, Hunan 410083, China
| | - Yong Zhang
- Central South University Xiangya School of Public Health, Changsha, Hunan 410078, China
| | - Lei Li
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Ping Ding
- Central South University Xiangya School of Public Health, Changsha, Hunan 410078, China.
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Wang L, Yu X, Liao J, Xue B, Tian S, Zhu W. Application of Fe 2O 3/ZrO 2 loaded polyhedron ball on photocatalytic degradation of diesel pollutants in seawater under visible light. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:1983-1993. [PMID: 32666951 DOI: 10.2166/wst.2020.252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Fe2O3/ZrO2 nanocomposite photocatalyst was successfully prepared by coprecipitation method for the degradation of diesel pollutants in seawater under visible light. The effects of doping ratio, calcination temperature, photocatalyst dosage, initial diesel concentration, H2O2 concentration, and reaction time on the photocatalytic removal efficiency were investigated. Moreover, the optimal conditions for Fe2O3/ZrO2 nanocomposite photocatalyst to degrade marine diesel pollution were determined. The removal efficiency of diesel by nanocomposite photocatalyst could reach 97.03%. A photocatalyst-loaded polypropylene polyhedral ball was prepared, and the removal efficiency of diesel by photocatalyst-loaded polypropylene polyhedral ball decreased from 99.35 to 68.84% after four recycling cycles.
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Affiliation(s)
- Liping Wang
- College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, China E-mail:
| | - Xiaocai Yu
- College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, China E-mail:
| | - Jiaqi Liao
- College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, China E-mail:
| | - Bining Xue
- College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, China E-mail:
| | - Siyao Tian
- College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, China E-mail:
| | - Wanting Zhu
- College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, China E-mail:
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Wang S, Zhang H, Ge H, Shi Y, Li Z. Photodegradation of microcystin-LR by pyridyl iron porphyrin immobilized on NaY zeolite. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:121-130. [PMID: 32293595 DOI: 10.2166/wst.2020.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A novel photocatalyst, FeTPyPY, was prepared by immobilizing water-soluble tetra(4-pyridyl)phenyl iron-porphyrin (FeTPyP) on NaY zeolite to degrade microcystin-LR (MC-LR), one of the most toxic microcystins (MCs). UV-Vis analysis, UV-Vis diffuse reflectance spectroscopy, infrared spectroscopy, cyclic voltammetry and transmission electron microscopy were employed to characterize immobilized FeTPyPY. Under visible light (λ ≥ 420 nm), MC-LR was degraded utilizing immobilized FeTPyPY by activating molecular oxygen. The results showed that 85% of MC-LR was efficiently degraded by FeTPyPY with loading amount 100:1 (mNaY:mFeTPyP) after 300 min of visible light illumination. Moreover, FeTPyPY was stable in the degradation system with pH 7.0. The degradation mechanism was evaluated using electron spin resonance, and the results demonstrated that highly reactive oxygen species (•OH radical) were generated in the system to degrade MC-LR. Therefore, immobilized FeTPyPY was available to break down the toxic groups within MC-LR by utilizing environmental •OH radical under circumneutral condition.
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Affiliation(s)
- Shulian Wang
- Hubei Key Laboratory of Ecological Remediation for Rivers-Lakes and Algal Utilization, School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China E-mail: ; Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Huiqin Zhang
- Hubei Key Laboratory of Ecological Remediation for Rivers-Lakes and Algal Utilization, School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China E-mail:
| | - Hongmei Ge
- Hubei Key Laboratory of Ecological Remediation for Rivers-Lakes and Algal Utilization, School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China E-mail:
| | - Yafei Shi
- Hubei Key Laboratory of Ecological Remediation for Rivers-Lakes and Algal Utilization, School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China E-mail:
| | - Zhu Li
- Hubei Key Laboratory of Ecological Remediation for Rivers-Lakes and Algal Utilization, School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China E-mail:
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Khedr TM, El-Sheikh SM, Ismail AA, Kowalska E, Bahnemann DW. Photodegradation of Microcystin-LR Using Visible Light-Activated C/N-co-Modified Mesoporous TiO₂ Photocatalyst. MATERIALS 2019; 12:ma12071027. [PMID: 30925688 PMCID: PMC6480059 DOI: 10.3390/ma12071027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 11/16/2022]
Abstract
Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing concern worldwide because of severe and persistent impacts on humans and animals by inhalation and consumption of contaminated waters and food. In this work, MC-LR was removed completely from aqueous solution using visible-light-active C/N-co-modified mesoporous anatase/brookite TiO₂ photocatalyst. The co-modified TiO₂ nanoparticles were synthesized by a one-pot hydrothermal process, and then calcined at different temperatures (300, 400, and 500 °C). All the obtained TiO₂ powders were analyzed by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), specific surface area (SSA) measurements, ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) analysis. It was found that all samples contained mixed-phase TiO₂ (anatase and brookite), and the content of brookite decreased with an increase in calcination temperature, as well as the specific surface area and the content of non-metal elements. The effects of initial pH value, the TiO₂ content, and MC-LR concentration on the photocatalytic activity were also studied. It was found that the photocatalytic activity of the obtained TiO₂ photocatalysts declined with increasing temperature. The complete degradation (100%) of MC-LR (10 mg L-1) was observed within 3 h, using as-synthesized co-modified TiO₂ (0.4 g L-1) at pH 4 under visible light. Based on the obtained results, the mechanism of MC-LR degradation has been proposed.
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Affiliation(s)
- Tamer M Khedr
- Nanomaterials and Nanotechnology Department, Central Metallurgical Research and Development Institute (CMRDI) P.O. Box: 87 Helwan, Cairo 11421, Egypt.
- Institute of Technical Chemistry, Photocatalysis and Nanotechnology Research Unit, Leibniz Universität Hannover, Callinstr. 3, D-30167 Hannover, Germany.
- Institute for Catalysis, Hokkaido University, N21, W10, Sapporo 001-0021, Japan.
| | - Said M El-Sheikh
- Nanomaterials and Nanotechnology Department, Central Metallurgical Research and Development Institute (CMRDI) P.O. Box: 87 Helwan, Cairo 11421, Egypt.
| | - Adel A Ismail
- Nanomaterials and Nanotechnology Department, Central Metallurgical Research and Development Institute (CMRDI) P.O. Box: 87 Helwan, Cairo 11421, Egypt.
- Nanotechnology and Advanced Materials Program, Energy & Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR), P.O. Box 24885, Safat 13109, Kuwait.
| | - Ewa Kowalska
- Institute for Catalysis, Hokkaido University, N21, W10, Sapporo 001-0021, Japan.
| | - Detlef W Bahnemann
- Institute of Technical Chemistry, Photocatalysis and Nanotechnology Research Unit, Leibniz Universität Hannover, Callinstr. 3, D-30167 Hannover, Germany.
- Laboratory "Photoactive Nanocomposite Materials" (Director), Saint-Petersburg State University, Ulyanovskaya str. 1, Peterhof, Saint-Petersburg 198504, Russia.
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Peng G, Lin S, Fan Z, Wang X. Transcriptional and Physiological Responses to Nutrient Loading on Toxin Formation and Photosynthesis in Microcystis Aeruginosa FACHB-905. Toxins (Basel) 2017; 9:toxins9050168. [PMID: 28513574 PMCID: PMC5450716 DOI: 10.3390/toxins9050168] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/08/2017] [Accepted: 05/11/2017] [Indexed: 01/15/2023] Open
Abstract
An important goal of understanding harmful algae blooms is to determine how environmental factors affect the growth and toxin formation of toxin-producing species. In this study, we investigated the transcriptional responses of toxin formation gene (mcyB) and key photosynthesis genes (psaB, psbD and rbcL) of Microcystis aeruginosa FACHB-905 in different nutrient loading conditions using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR). Three physio-biochemical parameters (malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH)) were also evaluated to provide insight into the physiological responses of Microcystis cells. We observed an upregulation of mcyB gene in nutrient-deficient conditions, especially in nitrogen (N) limitation condition, and the transcript abundance declined after the nutrient were resupplied. Differently, high transcription levels were seen in phosphorus (P) deficient treatments for key photosynthesis genes throughout the culture period, while those in N-deficient cells varied with time, suggesting an adaptive regulation of Microsystis cells to nutrient stress. Increased contents of antioxidant enzymes (SOD and GSH) were seen in both N and P-deficient conditions, suggesting the presence of excess amount of free radical generation caused by nutrient stress. The amount of SOD and GSH continued to increase even after the nutrient was reintroduced and a strong correlation was seen between the MDA and enzyme activities, indicating the robust effort of rebalancing the redox system in Microcystis cells. Based on these transcriptional and physiological responses of M. aeruginosa to nutrient loading, these results could provide more insight into Microcystis blooms management and toxin formation regulation.
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Affiliation(s)
- Guotao Peng
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
| | - Sijie Lin
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
| | - Zhengqiu Fan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Xiangrong Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
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