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Yu C, Peng M, Wang X, Pan X. Photochemical demethylation of methylmercury (MeHg) in aquatic systems: A review of MeHg species, mechanisms, and influencing factors. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123297. [PMID: 38195023 DOI: 10.1016/j.envpol.2024.123297] [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: 09/12/2023] [Revised: 12/01/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024]
Abstract
Photodemethylation is the major pathway of methylmercury (MeHg) demethylation in surface water before uptake by the food chain, whose mechanisms and influence factors are still not completely understood. Here, we review the current knowledge on photodemethylation of MeHg and divide MeHg photolysis into three pathways: (1) direct photodemethylation, (2) free radical attack, and (3) intramolecular electron or energy transfer. In aquatic environments, dissolved organic matter is involved into all above pathways, and due to its complex compositions, properties and concentrations, DOM poses multiple functions during the PD of MeHg. DOM-MeHg complex (mainly by sulfur-containing molecules) might weaken the C-Hg bond and enhance PD through both direct and indirect pathways. In special, synergistic effects of both strong binding sites and chromophoric moieties in DOM might lead to intramolecular electron or energy transfer. Moreover, DOM might play a role of radical scavenger; while triplet state DOM, which is generated by chromophoric DOM under light, might become a source of free radicals. Apart from DOMs, transition metals, halides, NO3-, NO2-, and carbonates also act as radical initialaters or scavengers, and significantly pose effects on radical demethylation, which is generally mediated by hydroxyl radicals and singlet oxygen. Environmental factors such as pH, light wavelength, light intensity, dissolved oxygen, salinity, and suspended particles also affect the PD of MeHg. This study assessed previously published works on three major mechanisms, with the goal of providing general estimates for photodemethylation under various environment factors according to know effects, and highlighting the current uncertainties for future research directions.
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Affiliation(s)
- Chenghao Yu
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Mao Peng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xiaonan Wang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
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Lotfi-Kalahroodi E, Le Bechec M, Tessier E, Pigot T, Amouroux D. Influence of oxygen, UV light and reactive dissolved organic matter on the photodemethylation and photoreduction of monomethylmercury in model freshwater. CHEMOSPHERE 2023; 330:138675. [PMID: 37076088 DOI: 10.1016/j.chemosphere.2023.138675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/06/2023] [Accepted: 04/10/2023] [Indexed: 05/03/2023]
Abstract
The key factors which affect the abiotic photodemethylation process of monomethylmercury (MMHg) in the freshwaters has remained unclear. Hence, this work aimed to better elucidate the abiotic photodemethylation pathway in a model freshwater. Anoxic and oxic conditions were implemented to investigate the simultaneous photodemethylation to Hg(II) and photoreduction to Hg(0). MMHg freshwater solution was irradiated through exposure to three wavelength ranges of full light (280-800 nm), without short UVB (305-800 nm), and visible light (400-800 nm). The kinetic experiments were performed following dissolved and gaseous Hg species concentrations (i.e., MMHg, iHg(II), Hg(0)). A comparison between two methods of post-irradiation purging and continuous-irradiation purging confirmed MMHg photodecomposition to Hg(0) is mainly induced by a first photodemethylation step to iHg(II) followed by a photoreduction step to Hg(0). Photodemethylation under full light extent normalized to absorbed radiation energy showed a higher rate constant in anoxic conditions at 18.0 ± 2.2 kJ-1 compared to oxic conditions at 4.5 ± 0.4 kJ-1. Moreover, photoreduction also increased up to four-fold under anoxic conditions. Normalized and wavelength-specific photodemethylation (Kpd) and photoreduction (Kpr) rate constants were also calculated for natural sunlight conditions to evaluate the role of each wavelength range. The relative ratio in wavelength-specific KPAR: Klong UVB+ UVA: K short UVB showed higher dependence on UV light for photoreduction at least ten-fold compared to photodemethylation, regardless of redox conditions. Both results using Reactive Oxygen Species (ROS) scavenging methods and Volatile Organic Compounds (VOC) measurements revealed the occurrence and production of low molecular weight (LMW) organic compounds that are as photoreactive intermediates responsible for MMHg photodemethylation and iHg(II) photoreduction in the dominant pathway. This study also supports the role of dissolved oxygen as an inhibitor for the photodemethylation pathways driven by LMW photosensitizers.
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Affiliation(s)
- Elaheh Lotfi-Kalahroodi
- Universite de Pau et des Pays de L'Adour, E2S/UPPA, CNRS, Institut des Sciences Analytiques et de Physico-chimie pour L'environnement et Les Matériaux (IPREM), 64000, Pau, France.
| | - Mickael Le Bechec
- Universite de Pau et des Pays de L'Adour, E2S/UPPA, CNRS, Institut des Sciences Analytiques et de Physico-chimie pour L'environnement et Les Matériaux (IPREM), 64000, Pau, France
| | - Emmanuel Tessier
- Universite de Pau et des Pays de L'Adour, E2S/UPPA, CNRS, Institut des Sciences Analytiques et de Physico-chimie pour L'environnement et Les Matériaux (IPREM), 64000, Pau, France
| | - Thierry Pigot
- Universite de Pau et des Pays de L'Adour, E2S/UPPA, CNRS, Institut des Sciences Analytiques et de Physico-chimie pour L'environnement et Les Matériaux (IPREM), 64000, Pau, France
| | - David Amouroux
- Universite de Pau et des Pays de L'Adour, E2S/UPPA, CNRS, Institut des Sciences Analytiques et de Physico-chimie pour L'environnement et Les Matériaux (IPREM), 64000, Pau, France
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Thara C, Korah BK, John BK, Mathew B. One-Pot Synthesized Multifunctional Carbon Nitride Dots for Fluorescent Sensing, Bioimaging, and Selective Cytotoxic Effect on Cancer Cells. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Jiao X, Li Z, He J, Wang C. Enhanced photodegradation of applied dithianon fungicides on plant leaves by dissolved substances in atmosphere under simulated sunlight. CHEMOSPHERE 2020; 254:126807. [PMID: 32334257 DOI: 10.1016/j.chemosphere.2020.126807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/06/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Photolysis of pesticides has been widely investigated for evaluating their environmental behavior and agricultural effectiveness after crop spraying. However, little information about the effects of the water-soluble substances in atmosphere on photodegradation of pesticides is available. In current study, we found that photolysis of applied dithianon fungicides on real plant leaves was much faster than that in sealed stock aqueous suspensions under simulated sunlight. To simulate the natural conditions, for the first time, photodegradation of dithianon in air-saturated solutions containing typical dissolved atmospheric substances (DAS) including CO2 (HCO3-/CO32-), NO2 (NO3-), Fe3+ (Fe3+-complexes), and humic-like substances (HULIS) exposed to simulated solar irradiations were carried out in lab-scale. Fulvic acid (FA) was used as a surrogate for atmospheric HULIS in this study. The dithianon photodegradation was significantly enhanced in the presence of DAS and the photo-generated reactive species such as ·OH, 1O2, CO3·- and 3FA∗ play important roles according to the results of reactive species quenching, electron spin resonance spectroscopy, and laser flash photolysis experiments. Moreover, the photodegraded intermediates and final products of dithianon on plant leaves have been identified by HPLC-MS analysis, and its possible photodegradation pathways were proposed. This work indicated that, except for direct photolysis, indirect photosensitive degradation induced by the dissolved photo-active substances in atmosphere should be considered for evaluating the degradation of the applied pesticides on crops.
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Affiliation(s)
- Xiaoyu Jiao
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, China
| | - Zhiling Li
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, 325035, China
| | - Jun He
- Department of Chemical and Environmental Engineering, University of Nottingham-Ningbo China, Ningbo, 315100, China
| | - Chengjun Wang
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, China.
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Luo H, Cheng Q, Pan X. Photochemical behaviors of mercury (Hg) species in aquatic systems: A systematic review on reaction process, mechanism, and influencing factor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 720:137540. [PMID: 32143045 DOI: 10.1016/j.scitotenv.2020.137540] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/23/2020] [Accepted: 02/23/2020] [Indexed: 06/10/2023]
Abstract
The fate and transport of Hg species in natural aquatic environment are strongly affected by photochemical transformation of Hg0, Hg2+, and MeHg. Migration of Hg is determined by its complexation with organic and inorganic ligands that are widely present in the water. The presence of dissolved organic matter (DOM) is closely related to photochemical reactions of Hg. DOM can strongly bind to mercury (e.g., Hg2+ and MeHg), thus affecting its speciation, mobility and toxicity, eventually dominating its bioavailability. This review summarizes extensive studies on photochemical behaviors of Hg including: (1) photo-oxidation; (2) photo-reduction; (3) photochemical methylation; and (4) MeHg photo-degradation. Photo-oxidation of Hg0 is mostly caused by oxidative free radicals (e.g., •OH, CO3•-, O3, and 1O2), while photo-reduction of Hg2+ is more complicated and it involves two pathways: (1) primary processes (direct photolysis of Hg2+ or ligand-metal charge transfer of Hg2+-DOM complex); and (2) secondary processes (reduction of Hg2+-DOM complex induced by free radicals derived from DOM photolysis). Photochemical methylation of inorganic Hg occurs as follows: (1) Hg2+ complexes with methyl donors (e.g., acetic acid, tert-butyl, alcohols, etc.) to form intermediates, followed by (2) an intramolecular methyl transfer. MeHg photo-degradation is the leading pathway for MeHg demethylation and it primarily proceeds via four different pathways. The information on DOM was also mentioned, but DOM is not the only factor that affects the photochemical behaviors of Hg. Other influencing factors such as: (1) pH value; (2) dissolved oxygen; (3) cations (Fe3+, K+) and anions (NO3-, HCO3-, CO32-, Cl-); and (4) suspended substance cannot be ignored.
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Affiliation(s)
- Hongwei Luo
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Qianqian Cheng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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Yu Q, Xiong X, He J, Zuo Y, Chen Y, Wang C. Photolysis of bis(2-ethylhexyl) phthalate in aqueous solutions at the presence of natural water photoreactive constituents under simulated sunlight irradiation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:26797-26806. [PMID: 31300990 DOI: 10.1007/s11356-019-05913-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
The photolysis of bis(2-ethylhexyl) phthalate (DEHP) under simulated sunlight in the presence of the natural water photoreactive constituents was investigated. The presence of nitrate or ferric ions facilitated the photodegradation of DEHP via oxidation by generation of •OH. The fulvic acids (FAs), at low concentrations, promoted the photolysis of DEHP via energy transfer from the photoreaction-generated 3FA*. However, the DEHP photolysis was inhibited with high concentrations of FAs since the excess FAs at the surface of solution could act as light screening agents to keep FAs in bulk solution from the light irradiation, further reducing the 3FA* generation. When low concentrations of FAs and chloride ions coexist, the reactive chloride species Cl• and Cl2•- could generate via energy transfer from 3FA* to chloride ions and react with DEHP to enhance its degradation. Furthermore, the direct and •OH-initiated DEHP photodegraded intermediates and end products were identified by HPLC-MS2 and its corresponding photolysis pathways were proposed.
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Affiliation(s)
- Qian Yu
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, China
| | - Xiyao Xiong
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, China
| | - Jun He
- Department of Chemical and Environmental Engineering, The University of Nottingham Ningbo China, Ningbo, 315100, China
| | - Yuegang Zuo
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA, 02747, USA
| | - Yong Chen
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chengjun Wang
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, China.
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Singh RP, Wu J, Fu D. Purification of water contaminated with Hg using horizontal subsurface constructed wetlands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:9697-9706. [PMID: 30734251 DOI: 10.1007/s11356-019-04260-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
As a global pollutant, Hg (Hg) since the turn of the last century has received increased attention. Decreasing the emission of Hg into the food chain and the atmosphere is an effective way to reduce the Hg damage. The current study provided information about pilot-scale horizontal subsurface flow (HSSF) constructed wetlands (CWs) to remove different Hg species in polluted water. Synthetic wastewater was fed to two HSSF CWs, one was planted with Acorus calamus L and the other was unplanted as a control. The total Hg (THg), dissolved Hg (DHg), and particulate Hg (PHg) from five sites along the HSSF CWs were analyzed to describe the process of Hg removal. Results show that the CWs have high removal efficiency of Hg which is more than 90%. The removal efficiencies of THg and DHg from the unplanted CW were 92.1 ± 3.6% and 72.4 ± 13.1%, respectively. While, the removal efficiencies of THg and DHg in planted CW were 95.9 ± 7.5% and 94.9 ± 4.9%, which were higher than that in blank CW. The PHg was mainly removed in the first quarter of the CWs, which was also revealed by the partition coefficient Kd. To a certain extent, the effect of plants depends on the hydraulic retention time (HRT). The results in the current study show the potential of the HSSF-CWs for restoration from Hg-contaminated water.
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Affiliation(s)
- Rajendra Prasad Singh
- Department of Municipal Engineering, School of Civil Engineering, Southeast University (SEU), Nanjing, 210096, China
- SEU-Monash Joint Research Centre for Future Cities, Nanjing, 210000, China
| | - Jiaguo Wu
- Department of Municipal Engineering, School of Civil Engineering, Southeast University (SEU), Nanjing, 210096, China
- SEU-Monash Joint Research Centre for Future Cities, Nanjing, 210000, China
| | - Dafang Fu
- Department of Municipal Engineering, School of Civil Engineering, Southeast University (SEU), Nanjing, 210096, China.
- SEU-Monash Joint Research Centre for Future Cities, Nanjing, 210000, China.
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Luo L, Mei K, Qu L, Zhang C, Chen H, Wang S, Di D, Huang H, Wang Z, Xia F, Dahlgren RA, Zhang M. Assessment of the Geographical Detector Method for investigating heavy metal source apportionment in an urban watershed of Eastern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 653:714-722. [PMID: 30759597 DOI: 10.1016/j.scitotenv.2018.10.424] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
Assessing heavy metal pollution in river sediments and identifying the key factors contributing to metal pollution are critical components for devising river environmental protection and remediation strategies to protect human and ecological health. This is especially important in urban areas where metals from a wide range of sources contribute to sediment pollution. In this study, the metal enrichment factor (EF) was used to measure the watershed distribution of Cu, Zn, Pb and Cd in sediments in the Wen-Rui Tang urban river system in Wenzhou, Eastern China. The Geographical Detector Method (GDM) was specifically evaluated for its ability to analyze spatial relationships between metal EFs and their anthropogenic and natural control factors, including densities of industry (DI), livestock (DL), service industries (DS), population (DP), and roads (DR), along with agricultural area (AG), sediment total organic carbon (TOC), and soil types (ST). Results showed that the watershed was highly contaminated by all metals with an EF trend of Cd ≫ Zn > Cu > Pb. The spatial distribution of EFs demonstrated high contamination of all metals in the southwestern region of the watershed where industrial activities were concentrated, and higher Cu and Zn concentrations in the northeastern region having a high density of livestock production. GDM results identified DI as the dominant determinant for all metals, while TOC and ST were determined to have a moderate secondary influence for Zn, Pb and Cd. Additionally, GDM revealed several additive and nonlinear interactions between anthropogenic and natural factors influencing metal concentrations. Compared to other correlation, multiple linear regression and geographically weighted regression, GDM demonstrated distinct advantages of being able to assess both categorical and continuous variables and determine both single and multiple factor interactions. These attributes provide a more comprehensive understanding of metal spatial distributions while avoiding multicollinearity issues when identifying significant contributing factors at the watershed scale.
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Affiliation(s)
- Lili Luo
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Kun Mei
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Liyin Qu
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Chi Zhang
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Han Chen
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Siyu Wang
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Di Di
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Hong Huang
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Zhenfeng Wang
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Fang Xia
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China
| | - Randy A Dahlgren
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China; Department of Land, Air and Water Resources, University of California, Davis, USA
| | - Minghua Zhang
- Zhejiang Provincial Key Laboratory of Watershed Sciences and Health, School of Public health and Management, Wenzhou Medical University, China; Southern Zhejiang Water Research Institute (iWATER), China; Department of Land, Air and Water Resources, University of California, Davis, USA.
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Wang G, Fan W, Li Q, Deng N. Enhanced photocatalytic New Coccine degradation and Pb(II) reduction over graphene oxide-TiO 2 composite in the presence of aspartic acid-β-cyclodextrin. CHEMOSPHERE 2019; 216:707-714. [PMID: 30391892 DOI: 10.1016/j.chemosphere.2018.10.199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/17/2018] [Accepted: 10/29/2018] [Indexed: 05/21/2023]
Abstract
In this work, aspartic acid-β-cyclodextrin (ACD) was synthesized by the reaction of β-cyclodextrin with aspartic acid and epichlorohydrin, and graphene oxide-TiO2 (GO-TiO2) composite catalyst was prepared by a hydrothermal method. The complexation of ACD with New Coccine (NC) and Pb2+ was characterized with FT-IR and XPS, respectively, the results show that ACD can simultaneously complex NC and Pb2+. XRD analysis and SEM images of GO-TiO2 show that TiO2 platelets are well distributed on both sides of the graphene oxide sheets, and display a similar XRD pattern to the pure TiO2 nanoparticles with the typical diffraction peak of anatase phase. The effects of ACD on the photocatalytic degradation of NC and photocatalytic reduction of Pb2+ were investigated in the single pollution system, and the synergistic effects on the simultaneous photocatalytic NC degradation and Pb2+ reduction in the presence of ACD were also evaluated. The results showed that the presence of ACD was favorable to the acceleration of photocatalytic oxidation of NC and photocatalytic reduction of Pb2+ in the single pollution system, and the photocatalytic reaction rate constants of NC and Pb2+ in the presence of ACD increased 58% and 42%, respectively. For the combined pollution system, the synergistic effects on the simultaneous conversion of NC and Pb2+ in aqueous solutions were also further enhanced. ACD enhanced photocatalytic activity was attributed to the improvement of the electron transfer and mass transfer at the GO-TiO2 interface.
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Affiliation(s)
- Guanghui Wang
- State Key Laboratory Breeding Base of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, PR China; School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang 330013, PR China.
| | - Wenzhe Fan
- State Key Laboratory Breeding Base of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, PR China
| | - Qin Li
- State Key Laboratory Breeding Base of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, PR China
| | - Nansheng Deng
- School of Resources and Environmental Science, Wuhan University, Wuhan 430079, PR China
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Wang X, Yang X, Wang N, Lv J, Wang H, Choi MMF, Bian W. Graphitic carbon nitride quantum dots as an "off-on" fluorescent switch for determination of mercury(II) and sulfide. Mikrochim Acta 2018; 185:471. [PMID: 30238322 DOI: 10.1007/s00604-018-2994-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 09/08/2018] [Indexed: 11/24/2022]
Abstract
A rapid method has been developed for the determination of Hg(II) and sulfide by using graphitic carbon nitride quantum dots (g-CNQDs) as a fluorescent probe. The interaction between Hg(II) and g-CNQDs leads to the quenching of the blue g-CNQD fluorescence (with excitation/emission peaks at 390/450 nm). However, the fluorescence can be recovered after addition of sulfide such that the "turn-off" state is switched back to the "turn-on" state. The g-CNQDs were fully characterized by transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-vis absorption and fluorescence spectroscopy. Under the optimal experimental conditions, this probe is highly selective and sensitive to Hg(II). The linear response to Hg(II) extends from 0.20 to 21 μM with a detection limit of 3.3 nM. In addition, sulfide can be detected via the recovery of fluorescence. The linear response range for sulfide species is from 8.0 to 45 μM with a detection limit of 22 nM. The mechanism of the "turn-off-on" scheme is discussed. The methods have been applied to the analysis of spiked tap water, lake water and wastewater samples. Graphical abstract Schematic of an off-on fluorescent probe for mercury(II). The fluorescence of graphitic carbon nitride quantum dots (g-CNQDs) is quenched by Hg2+ but is recovered after reacting with S2- as it can combine with Hg2+ on the surface of g-CNQDs.
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Affiliation(s)
- Xuan Wang
- Shanxi Medical University, Taiyuan, 030001, China
| | - Xuefang Yang
- Shanxi Medical University, Taiyuan, 030001, China
| | - Ning Wang
- Shanxi Medical University, Taiyuan, 030001, China
| | - Junjie Lv
- Shanxi Medical University, Taiyuan, 030001, China
| | | | - Martin M F Choi
- Bristol Chinese Christian Church, c/o Tyndale Baptist Church, 137-139 Whiteladies Road, Bristol, BS8 2QG, UK
| | - Wei Bian
- Shanxi Medical University, Taiyuan, 030001, China.
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Huang XG, Li SX, Liu FJ, Lan WR. Regulated effects of Prorocentrum donghaiense Lu exudate on nickel bioavailability when cultured with different nitrogen sources. CHEMOSPHERE 2018; 197:57-64. [PMID: 29331719 DOI: 10.1016/j.chemosphere.2018.01.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 01/03/2018] [Accepted: 01/05/2018] [Indexed: 05/25/2023]
Abstract
Exudates by marine phytoplankton and metals coexist in the seawater, but little is known about their interaction. In this study, cultures of Prorocentrum donghaiense Lu were grown in urea and ammonium, and then exposed to different Ni ion levels in order to study the effects of Ni ions on algal growth. The regulatory mechanisms of P. donghaiense Lu for coping with different Ni ion levels was investigating by characterizing dissolved organic carbon (DOC), carbohydrate and protein content released per cell, hydropathy properties (hydrophilic and hydrophobic fractions) and thiol compounds (cysteine-like or glutathione-like). Lower levels of Ni ions (pNi>10.0) significantly promoted the growth of P. donghaiense Lu when incubated in urea; however, the same was not true for P. donghaiense Lu cultivated in ammonium. An increased presence of hydrophobic fractions and thiol compounds (cysteine-like or glutathione-like compounds) induced by low Ni ions (pNi>10.0) in urea cultures suggest that the activation of cellular mechanisms in response to insufficient Ni ion stress enhances Ni bioavailability. Furthermore, the abundance of carbohydrates and proteins released by cells when exposed to higher Ni ions levels (from pNi = 10.0 to pNi = 8.0) both in urea and ammonium cultures suggests that algal cells may utilize exudate to complex Ni cations and reduce their toxicity. Therefore, it can be speculated that phytoplankton can produce large amounts of specific exudate, which may accelerate the metal bioavailability (insufficient levels) and reduce metal toxicity (excess levels) to maintain an equilibrium with metals in the environment.
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Affiliation(s)
- Xu-Guang Huang
- College of Chemistry and Environmental Science, Minnan Normal University, Zhangzhou, 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000, China.
| | - Shun-Xing Li
- College of Chemistry and Environmental Science, Minnan Normal University, Zhangzhou, 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000, China; Key Laboratory of Coastal and Wetland Ecosystems, Ministry of Education, Xiamen University, Xiamen, 361005, China
| | - Feng-Jiao Liu
- Key Laboratory of Coastal and Wetland Ecosystems, Ministry of Education, Xiamen University, Xiamen, 361005, China
| | - Wang-Rong Lan
- College of Chemistry and Environmental Science, Minnan Normal University, Zhangzhou, 363000, China
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