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Hu S, Ye L, Tian BJ, Li JY, Zhang AY, Zhao L, Zhang C, Jiang C, Lin ZX, Da W, Wei QX. Humic substances mediated superior photochemical pollutant conversion on defective TiO 2 in environmentally relevant matrices: The key roles of oxygen vacancy in surface interactions, oxidant activation and radical generation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171145. [PMID: 38395167 DOI: 10.1016/j.scitotenv.2024.171145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
Ubiquitous humic substances usually exhibit strong interfering effects on target pollutant removal in advanced water purification. This work aims to develop a photochemical conversion system on the nonstoichiometric TiO2 for pollutant removal in environmentally relevant matrices. In this synergistic reaction system, the redox-reactive humic substances and defective oxygen vacancies can serve as the organic electron transfer mediator and the key surface reactive sites, respectively. This system achieves a superior pollutant degradation in real surface water at low oxidant concentrations. Reactive oxygen vacancies on the TiO2 surface and sub-surface are of considerable interest for this photochemical reaction system. By engineering defective oxygen vacancies on high-energy {001} polar facet, the surface and electronic interactions between tailored TiO2 and humic substances are greatly strengthened for the promoted electron transfer and oxidant activation. Rendered by the strong surface affinity and molecular activation, defective oxygen vacancies thermodynamically and dynamically promote reactive chain reactions for free radical formation, including the selective O2 reduction to ·O2- and the H2O2 activation to ·OH. Our findings take new insights into environmental geochemistry, and provide an effective strategy to in-situ boost the humic substances-mediated water purification without secondary pollution. ENVIRONMENTAL IMPLICATION: Humic substances are widely distributed in aquatic environment, thus playing important roles in environmental geochemistry. For example, humic substances can achieve good surface adsorption through electrostatic adsorption, ligand exchange and electronic interactions with typical TiO2 to form reactive ligand-metal charge transfer complexes for pollutant degradation. Inspired by the unique properties of surface and sub-surface oxygen vacancies, the defective TiO2 was designed to refine the humic substances-mediated photochemical reactions. A superior reactivity was measured for pollutant degradation. Our findings provide an effective strategy to boost naturally photochemical decontamination in environmentally relevant matrices.
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Affiliation(s)
- Song Hu
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Lyumeng Ye
- Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, the Ministry of Ecology and Environment of PRC, Guangzhou 510655, China
| | - Bing-Jie Tian
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jia-Ying Li
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Ai-Yong Zhang
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China; Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, the Ministry of Ecology and Environment of PRC, Guangzhou 510655, China.
| | - Lu Zhao
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Chi Zhang
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Chu Jiang
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Zhi-Xian Lin
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Wei Da
- Anhui Engineering Laboratory for Rural Water Environment and Resources, School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Qi-Xin Wei
- Key Laboratory of Aqueous Environment Protection and Pollution Control of Yangtze River in Anhui, Anqing Normal University, Anqing 246011, China.
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Li X, Wei H, Song T, Lu H, Wang X. A review of the photocatalytic degradation of organic pollutants in water by modified TiO 2. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2023; 88:1495-1507. [PMID: 37768751 PMCID: wst_2023_288 DOI: 10.2166/wst.2023.288] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Organic pollutants in water bodies pose a serious environmental problem, and photocatalytic technology is an efficient and environmentally friendly water treatment method. Titanium dioxide (TiO2) is a widely used photocatalyst, but it suffers from some drawbacks such as a narrow light response range, fast charge recombination, and low photocatalytic activity. To improve the photocatalytic performance of TiO2, this article reviews the preparation methods, performance evaluation, and applications of modified TiO2 photocatalysts. Firstly, the article introduces the effects of doping modification, semiconductor composite modification, and other modification methods on the structure and properties of TiO2 photocatalysts, as well as the common characterization techniques and activity test methods of photocatalysts. Secondly, the article discusses the effects and mechanisms of modified TiO2 photocatalysts on degrading dye, pesticide, and other organic pollutants in water bodies, as well as the influencing factors. Finally, the article summarizes the main achievements and advantages of modified TiO2 photocatalysts in degrading organic pollutants in water bodies, points out the existing problems and challenges, and prospects for the development direction and future of this field.
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Affiliation(s)
- Xueqi Li
- Changchun University of Architecture and Civil Engineering, Changchun 130000, China E-mail:
| | - Hongyan Wei
- Changchun University of Architecture and Civil Engineering, Changchun 130000, China
| | - Tiehong Song
- Changchun University of Architecture and Civil Engineering, Changchun 130000, China
| | - Hai Lu
- Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun City, Jilin Province, China
| | - Xiaoyan Wang
- Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun City, Jilin Province, China
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Liu B, Han Z, Pan Y, Liu X, Zhang M, Wan A, Wang Z. Synergistic Effects of Organic Ligands and Visible Light on the Reductive Dissolution of CeO 2 Nanoparticles: Mechanisms and Implications for the Transformation in Plant Surroundings. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11999-12009. [PMID: 37535498 DOI: 10.1021/acs.est.3c03216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Cerium oxide (CeO2) nanoparticles are one of the most important engineered nanomaterials with demonstrated applications in industry. Although numerous studies have reported the plant uptake of CeO2, its fate and transformation pathways and mechanisms in plant-related conditions are still not well understood. This study investigated the stability of CeO2 in the presence of organic ligands (maleic and citric acid) and light irradiation. For the first time, we found that organic ligands and visible light had a synergistic effect on the reductive dissolution of CeO2 with up to 30% Ce releases after 3 days, which is the highest release reported so far under environmental conditions. Moreover, the photoinduced dissolution of CeO2 in the presence of citrate was much higher than that in maleate, which are adsorbed on the surface of CeO2 through inner-sphere and outer-sphere complexation, respectively. A novel ligand-dependent photodissolution mechanism was proposed and highlighted: upon electron-hole separation under light irradiation, the inner-sphere complexed citrate is more capable of consuming the hole, prolonging the life of electrons for the reduction of Ce(IV) to Ce(III). Finally, reoxidation of Ce(III) by oxygen was observed and discussed. This comprehensive work advances our knowledge of the fate and transformation of CeO2 in plant surroundings.
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Affiliation(s)
- Bei Liu
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zixin Han
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yu Pan
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xun Liu
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Meng Zhang
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Aling Wan
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhongying Wang
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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Zhong H, Lu C, Sun XL, Luo Y, Qian Q, Xue H, Yang MQ. Visible-Light-Driven Photocatalytic Dehydrogenation of Alcohols on TiO 2 via Ligand-to-Metal Charge Transfer for Coproduction of H 2 and Aldehydes. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37486250 DOI: 10.1021/acsami.3c06701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Developing visible-light-driven photocatalysts for the catalytic dehydrogenation of organics is of great significance for sustainable solar energy utilization. Here, we first report that aromatic alcohols could be efficiently split into H2 and aldehydes over TiO2 under visible-light irradiation through a ligand-to-metal charge transfer (LMCT) mechanism. A series of TiO2 catalysts with different surface contents of the hydroxyl group (-OH) have been synthesized by controlling the hydrothermal and calcination synthesis methods. An optimal H2 production rate of 18.6 μmol h-1 is obtained on TiO2 synthesized from the hydrothermal method with a high content of surface -OH. Experimental characterizations and comparison studies reveal that the surface -OH markedly influences the formation of LMCT complexes and thus changes the visible-light-driven photocatalytic performance. This work is anticipated to inspire further research endeavors in the design and fabrication of visible-light-driven photocatalyst systems based on the LMCT mechanism to realize the simultaneous synthesis of clean fuel and fine chemicals.
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Affiliation(s)
- Huiling Zhong
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
| | - Chengjing Lu
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
| | - Xiao-Li Sun
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
| | - Yongjin Luo
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
| | - Qingrong Qian
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
| | - Hun Xue
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
| | - Min-Quan Yang
- College of Environmental and Resource Sciences, College of Carbon Neutral Modern Industry, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, P. R. China
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In situ generation of hydroxyl radicals by B-doped TiO 2 for efficient photocatalytic degradation of acetaminophen in wastewater. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:46997-47011. [PMID: 36735135 DOI: 10.1007/s11356-023-25390-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 01/14/2023] [Indexed: 02/04/2023]
Abstract
Acetaminophen (AP) is a widely used antipyretic analgesic belonging to the class of PPCPs, which is difficult to be effectively degraded by traditional water treatment processes. However, photocatalytic technology may be an effective approach. Herein, B-doped TiO2 photocatalytic materials were synthesized by sol-gel method, calcinated at 600℃ for 2 h, investigated by XRD, TEM, XPS, and other characterization methods. The photocatalytic efficiency and factors affecting the photocatalytic activity were assessed by degradation of AP under 365 nm UV light. Compared with undoped TiO2, 4%B-TiO2 nanopowder has smaller grain size, higher porosity, and lower bandgap energy of 3.11 eV. Scavenging experiments and ESR results show that •OH is the principal active species. Hence, the degradation efficiency of AP is as high as 98.8% in 30 min when adopting 10-mg/L AP initial concentration and 1-g/L 4%B-TiO2 loading, owing to efficient •OH generated by B-TiO2.
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Titanium dioxide nanoparticle-based hydroxyl and superoxide radical production for oxidative stress biological simulations. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yu SY, Liu Y, Ren HT, Liu ZY, Han X. Importance of the ligand-to-metal charge transfer (LMCT) pathway in the photocatalytic oxidation of arsenite by TiO 2. Phys Chem Chem Phys 2022; 24:13661-13670. [PMID: 35611917 DOI: 10.1039/d1cp04752c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photooxidation of As(III) by TiO2 is a complicated process in which the oxidation mechanisms are always controversial. In this study, the enhanced photooxidation rates of As(III) with increasing pH values from 8.0 to 11.0 indicate the high photocatalytic reactivity of TiO2 under alkaline conditions. Moreover, As(III) improves the production of H2O2, indicating H-abstraction from As(III) (soluble or adsorbed) for H2O2 production. Although O2˙-, h+, ˙OH and -OOH are always regarded as the reactive oxygen species in the UV-TiO2 system, the superoxo and peroxo species formed on the surface of TiO2 also contribute to As(III) oxidation. The As(III)-O-Ti(IV) surface complexes formed on TiO2, as well as the decreased bandgaps of TiO2 with increasing concentrations of As(III) indicate that the ligand-to-metal charge transfer (LMCT) pathway also contributes to the oxidation of As(III) under alkaline conditions. Electrochemical analyses further reveal that As(III) enhances the electron density on the surface of TiO2, thereby improving the catalytic reactivity of TiO2. We therefore suggest that H-abstraction from As(III) or H2O to the formed superoxo and peroxo species results in the formation of H2O2, accompanied by the oxidation of As(III). This enriches our knowledge on the oxidation of As(III), as well as other contaminants rich in -OH groups during the photocatalytic oxidation processes.
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Affiliation(s)
- Si-Yuan Yu
- School of Environmental Science and Engineering, Tiangong University, Tianjin, P. R. China
| | - Ying Liu
- School of Environmental Science and Engineering, Tiangong University, Tianjin, P. R. China
| | - Hai-Tao Ren
- School of Textile Science and Engineering, Tiangong University, Tianjin, P. R. China.
| | - Zhao-Yu Liu
- School of Environmental Science and Engineering, Tiangong University, Tianjin, P. R. China
| | - Xu Han
- Key Lab of Indoor Air Environment Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, P. R. China.
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Moumen E, Bazzi L, El Hankari S. Metal-organic frameworks and their composites for the adsorption and sensing of phosphate. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214376] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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