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Belaidi S, Sangare S, Remache W, Belattar S, Seraghni N, Sehili T. Enhanced degradation of 2,6-dimethylphenol by photocatalytic systems using TiO 2 assisted with H 2O 2 and Fe(III). ENVIRONMENTAL TECHNOLOGY 2023; 44:1464-1477. [PMID: 34779714 DOI: 10.1080/09593330.2021.2005686] [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: 04/16/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
In this study, several photocatalytic degradation systems were investigated using 2,6-dimethylphenol (2,6-DMP) as a model compound. Highly reactive species are formed in four systems, Fe(III), TiO2, TiO2/H2O2 and TiO2/Fe(III) where complete degradation of 2,6-DMP was achieved under UV radiation. Photodegradation of the 2,6-DMP has been described by pseudo-first order kinetic model in the presence of TiO2. In UV/TiO2-H2O2 system, the addition of H2O2 in the TiO2 suspension improves the degradation rate of 2,6-DMP from 70% to 100% for a H2O2 concentration of 10-2 M in 3 h. In homogeneous system, HO• and Fe2+ can be generated by the irradiation of Fe(III) solution. The speciation of Fe(III) obtained from Visual MINTEQ soft showed the formation of several species and Fe(OH)2+ were the most predominant and active species in a pH range of 2.5-3.5. At a low concentration of TiO2 (30 mg L-1), an important positive effect due to the iron addition has been shown in TiO2/Fe(III) system, the entrance of metallic ions at different concentrations enhanced the photocatalytic activity of TiO2. A degradation percentage of 90% was achieved in the UV/TiO2-Fe(III) system under optimal conditions against 57% in UV/TiO2 system. Strong synergistic effect was observed in the UV/TiO2-H2O2 binary system. On the basis of literature, a pathway for 2,6-DMP degradation was proposed. The mechanism of degradation of the 2,6-DMP did not involve only HO• radicals, an interaction of Fe(III) in the excited state with 2,6-DMP occurred giving rise to the formation of 2,6-dimethylphenoxyl radical.
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Affiliation(s)
- S Belaidi
- Faculty of Exact Sciences, Laboratory of Sciences and Technology of Environment, University of Constantine 1, Constantine, Algeria
| | - S Sangare
- Faculty of Exact Sciences, Laboratory of Sciences and Technology of Environment, University of Constantine 1, Constantine, Algeria
| | - W Remache
- Faculty of Exact Sciences, Laboratory of Sciences and Technology of Environment, University of Constantine 1, Constantine, Algeria
| | - S Belattar
- Faculty of Exact Sciences, Laboratory of Sciences and Technology of Environment, University of Constantine 1, Constantine, Algeria
| | - N Seraghni
- Faculty of Exact Sciences, Laboratory of Sciences and Technology of Environment, University of Constantine 1, Constantine, Algeria
| | - T Sehili
- Faculty of Exact Sciences, Laboratory of Sciences and Technology of Environment, University of Constantine 1, Constantine, Algeria
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Simultaneous Quantification of Bisphenol-A and 4-Tert-Octylphenol in the Live Aquaculture Feed Artemia franciscana and in Its Culture Medium Using HPLC-DAD. Methods Protoc 2022; 5:mps5030038. [PMID: 35645346 PMCID: PMC9149995 DOI: 10.3390/mps5030038] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 11/30/2022] Open
Abstract
Aquaculture, a mass supplier of seafood, relies on plastic materials that may contain the endocrine disruptors bisphenol-A (BPA) and tert-octylphenol (t-OCT). These pollutants present toxicity to Artemia, the live aquaculture feed, and are transferred through it to the larval stages of the cultured organisms. The purpose of this work is the development and validation of an analytical method to determine BPA and t-OCT in Artemia and their culture medium, using n-octylphenol as the internal standard. Extraction of the samples was performed with H2O/TFA (0.08%)–methanol (3:1), followed by SPE. Analysis was performed in a Nucleosil column with mobile phases A (95:5, v/v, 0.1% TFA in H2O:CH3CN) and B (5:95, v/v, 0.08% TFA in H2O:CH3CN). Calibration curves were constructed in the range of concentrations expected following a 24 h administration of BPA (10 μg/mL) or t-OCT (0.5 μg/mL), below their respective LC50. At the end of exposure to the pollutants, their total levels appeared reduced by about 32% for BPA and 35% for t-OCT, and this reduction could not be accounted for by photodegradation (9–19%). The developed method was validated in terms of linearity, accuracy, and precision, demonstrating the uptake of BPA and t-OCT in Artemia.
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Yao Y, Hu X, Zhang Y, He H, Li S. Visible light promoted the removal of tetrabromobisphenol A from water by humic acid-FeS colloid. CHEMOSPHERE 2022; 289:133192. [PMID: 34890606 DOI: 10.1016/j.chemosphere.2021.133192] [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: 08/17/2021] [Revised: 11/18/2021] [Accepted: 12/04/2021] [Indexed: 06/13/2023]
Abstract
Ferrous sulfide (FeS) and humic acid (HA) are typical black substances in black bloom water. Based on the strong reduction ability of FeS and the photosensitivity of HA, the transformation of toxic organic pollutants by the combination of FeS and HA (HA-FeS) is not clear. In order to explore this issue, the stability of HA-FeS was analyzed by measuring the hydrodynamic diameter and zeta potential of HA-FeS, and then the removal mechanism and possible degradation pathway of tetrabromobisphenol A (TBBPA) by HA-FeS under continuous illumination were discussed. The results showed that the hydrodynamic diameter of FeS was reduced and the stability of FeS was improved, and it was easily suspended after FeS combined with the HA in the water. The combination of HA and FeS promoted the removal of TBBPA in water, no matter it was in the presence or absence of light. Besides, compared with the absence of light, the removal efficiency of TBBPA was improved by HA-FeS with continuous light. There were two reasons for the increase in the removal efficiency of TBBPA by HA-FeS. On the one hand, Fe2+ and S2- of HA-FeS had more stable chemical valence and obtained better reducibility under continuous light than that in the dark. On the other hand, light induced the release of active species (O2-, 1O2, and OH) in the HA-FeS composite colloid and further promoted the degradation of organic pollutants. Therefore, the black substances (FeS) of black blooms may play a beneficial role in the removal of pollutants under sunlight.
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Affiliation(s)
- Youru Yao
- School of Environment, Nanjing Normal University, Nanjing, 210023, China; Key Laboratory of Earth Surface Processes and Regional Response in the Yangtze-Huaihe River Basin, Anhui Province, School of Geography and Tourism, Anhui Normal University, Wuhu, 241002, China
| | - Xin Hu
- School of Environment, Nanjing Normal University, Nanjing, 210023, China
| | - Yong Zhang
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing, 210023, China.
| | - Shiyin Li
- School of Environment, Nanjing Normal University, Nanjing, 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, 210023, China.
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Sadhu SP, Ruparelia JP, Patel UD. Homogeneous photocatalytic degradation of azo dye Reactive Black 5 using Fe(III) ions under visible light. ENVIRONMENTAL TECHNOLOGY 2022; 43:199-206. [PMID: 32538321 DOI: 10.1080/09593330.2020.1782995] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
Efficient and cost-effective method to destroy complex dyes is warranted to combat increasing water pollution. In the present study, homogeneous photocatalytic oxidation (PCO) of Reactive Black 5 (RB5) dye was studied using ferric ions (Fe(III)) under visible light (VL) irradiation and sunlight (SL). In the presence of 5 mM ferric ions and at pH 2.6, more than 80% of initial 20 mg/L RB5 was decolourized in 60 min under artificial VL. Decolourization followed pseudo first-order kinetics with the reaction rate constant 0.0356 min-1. 79% of initial COD was removed at the end of 60 min, suggesting mineralization of RB5 as the main cause of decolourization. Using similar experimental conditions under SL, more than 90% RB5 was decolourized in 15 min with an almost 10-fold increase in the reaction rate constant (0.34 min-1). Rate and extent of RB5 destruction significantly decreased in the presence of •OH scavenger indicating photoreduction of Fe-hydroxo species and generation of •OH as the main mechanism of RB5 degradation. RB5 removal increased from ca. 30% to 84% with the increase in Fe(III) concentration from 0.5 to 5 mM. The corresponding 1st-order rate constants increased linearly from 0.006 to 0.036 min-1. RB5 degradation decreased linearly (R2 = 0.98) from 91.7% to 63.3% with the increase in initial RB5 concentration from 10 to 40 mg/L. Fe(III) induced homogenous PCO appears to be a reliable and low-cost method of advanced oxidation without the need for costly reagent such as H2O2.
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Affiliation(s)
- Shailaja P Sadhu
- Civil Engineering Department, Faculty of Technology & Engineering, The M. S. University of Baroda, Vadodara, India
| | - J P Ruparelia
- Chemical Engineering Department, Institute of Technology, Nirma University, Ahmedabad, India
| | - Upendra D Patel
- Civil Engineering Department, Faculty of Technology & Engineering, The M. S. University of Baroda, Vadodara, India
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Chen N, Wang X, Wan Y, Luo Y, Huang Y, Zhang L. Simulated solar light driven Fe(III)/Fe(II) redox cycle for roxarsone degradation and simultaneous arsenate immobilization. JOURNAL OF HAZARDOUS MATERIALS 2020; 394:121635. [PMID: 32289620 DOI: 10.1016/j.jhazmat.2019.121635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 10/28/2019] [Accepted: 11/07/2019] [Indexed: 06/11/2023]
Abstract
Organoarsenicals remediation requires degrading organoarsenicals and simultaneously immobilizing the resulted inorganic arsenic, and is thus a great challenge. In this study, a simulated solar light driven Fe(III)/Fe(II) cycle strategy was developed to degrade roxarsone and immobilize the generated inorganic arsenic via tuning the degree of Fe(III) hydrolysis. At pH values of 2.0 and 3.0, the hydrolysis of Fe(III) in the solution was suppressed to produce photoreactive Fe(III)-hydroxyl complexes, which could be excited by simulated solar light to generate OH for 85.3 % of roxarsone degradation into arsenate within 60 min. Density functional theory calculations suggested that Fe(OH)(H2O)52+ with lower energy separation gap was the most photoactive Fe(III)-hydroxyl complex for OH generation. With further increasing pH value to 6.0, the hydrolysis of Fe(III) was promoted to precipitate the arsenate for its immobilization, accompanying with the decrease of final iron ions and arsenate concentrations to 0.012 mmol L-1 and 58 μg L-1, respectively. Meanwhile, the undegraded roxarsone was also adsorbed by the precipitate, increasing the overall roxarsone removal efficiency to 99.0 %. This study offers a promising strategy for the efficient organoarsenicals treatment, and also sheds light on the dual effects of iron based materials in organic pollutants degradation and heavy metal ions immobilization.
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Affiliation(s)
- Na Chen
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Xiaobing Wang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Yichao Wan
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Yani Luo
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Yunhua Huang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.
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Olaniyan LWB, Okoh OO, Mkwetshana NT, Okoh AI. Environmental Water Pollution, Endocrine Interference and Ecotoxicity of 4-tert-Octylphenol: A Review. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 248:81-109. [PMID: 30460491 DOI: 10.1007/398_2018_20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
4-tert-Octylphenol is a degradation product of non-ionic surfactants alkylphenol polyethoxylates as well as raw material for a number of industrial applications. It is a multimedia compound having been detected in all environmental compartments such as indoor air and surface waters. The pollutant is biodegradable, but certain degradation products are more toxic than the parent compound. Newer removal techniques from environmental waters have been presented, but they still require development for large-scale applications. Wastewater treatment by plant enzymes such as peroxidases offers promise in total removal of 4-tert-octylphenol leaving less toxic degradation products. The pollutant's endocrine interference has been well reported but more in oestrogens than in any other signalling pathways through which it is believed to exert toxicity on human and wildlife. In this paper we carried out a review of the activities of this pollutant in environmental waters, endocrine interference and relevance to its toxicities and concluded that inadequate knowledge of its endocrine activities impedes understanding of its toxicity which may frustrate current efforts at ridding the compound from the environment.
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Affiliation(s)
- Lamidi W B Olaniyan
- South Africa Medical Research Council, Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa.
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa.
| | - Omobola O Okoh
- South Africa Medical Research Council, Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa
- Department of Pure and Applied Chemistry, University of Fort Hare, Alice, South Africa
| | - Noxolo T Mkwetshana
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
| | - Anthony I Okoh
- South Africa Medical Research Council, Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa
- Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
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Qiao Y, Chen G, Ma C, Tao B, Ma H, Zhang X, Liu F. Identification of photoproducts of florasulam in water using UPLC-QTOF-MS. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:7132-7142. [PMID: 30649695 DOI: 10.1007/s11356-019-04169-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 01/04/2019] [Indexed: 06/09/2023]
Abstract
Here, we aimed to investigate florasulam photodegradation in aquatic environments under UV-visible irradiation. LC-MS/MS was used to explore the photolysis kinetics of florasulam degradation with respect to different light source types, florasulam concentrations, water sources, and pH. We also tested whether the addition of the nitrate ions, Fe3+, or I- to the reaction solution influences florasulam photolysis kinetics. NO3- accelerates florasulam degradation at low concentrations (0.01-1 mg L-1), but decreases the process at higher concentrations. At low concentrations (≤ 0.1 mg L-1), Fe3+ enhanced florasulam photodegradation obviously. However, the addition of 0.01-10 mg L-1 I- decreased the degradation rate linearly. The florasulam photolysis rates in alkaline and neutral solutions were higher than that in acidic solutions. The florasulam degradation rate under mercury light irradiation was greater than that under xenon light. The rate of florasulam degradation in distilled water was greater than in tap water, lake water, and rice paddy water. As the concentration of florasulam increased, the photodegradation rate decreased. Six kinds of transformation products (TPs) were isolated and identified using UPLC/Q-TOF-MS. Based on these TPs and their evolutionary processes, we inferred the florasulam degradation mechanisms, identifying four possible florasulam degradation pathways. Cleavage of the florasulam sulfonamide bond yielded TPs2. TPs2 was intermolecularly rearranged to form a SO2 extrusion compound, TPs3. Cleavage of the [C-F] bonds led to the formation of TPsl, TPs4, and TPs5, while hydroxylation led to the formation of TPs6. We then predicted the stability of each of the florasulam TPs in water. TPs2 and TPs3 rapidly degraded after reaching maximum concentration due to poor light stability. TPs4 and TPs6 were more photostable than florasulam (the parent compound) and may be important contributors to water pollution.
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Affiliation(s)
- Yuxin Qiao
- College of Agriculture, Northeast Agricultural University, Harbin, 150030, China
| | - Guofeng Chen
- College of Agriculture, Northeast Agricultural University, Harbin, 150030, China
- Safety and Quality Institute of Agricultural Products, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
| | - Chengyi Ma
- College of Agriculture, Northeast Agricultural University, Harbin, 150030, China
| | - Bo Tao
- College of Agriculture, Northeast Agricultural University, Harbin, 150030, China.
| | - Hong Ma
- College of Agriculture, Northeast Agricultural University, Harbin, 150030, China
| | - Xiaobo Zhang
- Safety and Quality Institute of Agricultural Products, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
| | - Feng Liu
- Safety and Quality Institute of Agricultural Products, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
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Rajendran RK, Huang SL, Lin CC, Kirschner R. Biodegradation of the endocrine disrupter 4-tert-octylphenol by the yeast strain Candida rugopelliculosa RRKY5 via phenolic ring hydroxylation and alkyl chain oxidation pathways. BIORESOURCE TECHNOLOGY 2017; 226:55-64. [PMID: 27987401 DOI: 10.1016/j.biortech.2016.11.129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 06/06/2023]
Abstract
4-(1,1,3,3-tetramethylbutane)-phenol (4-tert-OP) is one of the most prevalent endocrine disrupting pollutants. Information about bioremediation of 4-tert-OP remains limited, and no study has been reported on the mechanism of 4-tert-OP degradation by yeasts. The yeast Candida rugopelliculosa RRKY5 was proved to be able to utilize 4-methylphenol, bisphenol A, 4-ethylphenol, 4-tert-butylphenol, 4-tert-OP, 4-tert-nonylphenol, isooctane, and phenol under aerobic conditions. The optimum conditions for 4-tert-OP degradation were 30°C, pH 5.0, and an initial 4-tert-OP concentration of 30mgL-1; the maximum biodegradation rate constant was 0.107d-1, equivalent to a minimum half-life of 9.6d. Scanning electron microscopy revealed formation of arthroconidia when cells were grown in the presence of 4-tert-OP, whereas the cells remained in the budding form without 4-tert-OP. Identification of the 4-tert-OP degradation metabolites using liquid chromatography-hybrid mass spectrometry revealed three different mechanisms via both branched alkyl side chain and aromatic ring cleavage pathways.
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Affiliation(s)
- Ranjith Kumar Rajendran
- Department of Life Sciences, National Central University, No. 300, Zhongda Rd., Zhongli District, Taoyuan City 32001, Taiwan
| | - Shir-Ly Huang
- Department of Life Sciences, National Central University, No. 300, Zhongda Rd., Zhongli District, Taoyuan City 32001, Taiwan
| | - Chu-Ching Lin
- Graduate Institute of Environmental Engineering, National Central University, No. 300, Zhongda Rd., Zhongli District, Taoyuan City 32001, Taiwan
| | - Roland Kirschner
- Department of Life Sciences, National Central University, No. 300, Zhongda Rd., Zhongli District, Taoyuan City 32001, Taiwan.
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Ribeiro AR, Nunes OC, Pereira MFR, Silva AMT. An overview on the advanced oxidation processes applied for the treatment of water pollutants defined in the recently launched Directive 2013/39/EU. ENVIRONMENT INTERNATIONAL 2015; 75:33-51. [PMID: 25461413 DOI: 10.1016/j.envint.2014.10.027] [Citation(s) in RCA: 413] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/26/2014] [Accepted: 10/28/2014] [Indexed: 05/25/2023]
Abstract
Environmental pollution is a recognized issue of major concern since a wide range of contaminants has been found in aquatic environment at ngL(-1) to μgL(-1) levels. In the year 2000, a strategy was defined to identify the priority substances concerning aquatic ecosystems, followed by the definition of environmental quality standards (EQS) in 2008. Recently it was launched the Directive 2013/39/EU that updates the water framework policy highlighting the need to develop new water treatment technologies to deal with such problem. This review summarizes the data published in the last decade regarding the application of advanced oxidation processes (AOPs) to treat priority compounds and certain other pollutants defined in this Directive, excluding the inorganic species (cadmium, lead, mercury, nickel and their derivatives). The Directive 2013/39/EU includes several pesticides (aldrin, dichlorodiphenyltrichloroethane, dicofol, dieldrin, endrin, endosulfan, isodrin, heptachlor, lindane, pentachlorophenol, chlorpyrifos, chlorfenvinphos, dichlorvos, atrazine, simazine, terbutryn, diuron, isoproturon, trifluralin, cypermethrin, alachlor), solvents (dichloromethane, dichloroethane, trichloromethane and carbon tetrachloride), perfluorooctane sulfonic acid and its derivatives (PFOS), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), nonylphenol and octylphenol, as well as the three compounds included in the recommendation for the first watch list of substances (diclofenac, 17-alpha-ethinylestradiol (EE2) and 17-beta-estradiol (E2)). Some particular pesticides (aclonifen, bifenox, cybutryne, quinoxyfen), organotin compounds (tributyltin), dioxins and dioxin-like compounds, brominated diphenylethers, hexabromocyclododecanes and di(2-ethylhexyl)phthalate are also defined in this Directive, but studies dealing with AOPs are missing. AOPs are recognized tools to destroy recalcitrant compounds or, at least, to transform them into biodegradable species. Diuron (a phenylurea herbicide) and atrazine (from the triazine chemical class) are the most studied pesticides from Directive 2013/39/EU. Fenton-based processes are the most frequently applied to treat priority compounds in water and their efficiency typically increases with the operating temperature as well as under UV or solar light. Heterogeneous photocatalysis is the second most used treatment to destroy pollutants defined in the Directive. Ozone alone promotes the partial oxidation of pollutants, and an increase in the effluent biodegradability, but complete mineralization of pollutants is difficult. To overcome this drawback, ozonation has been combined with heterogeneous catalysts, addition of H2O2, other AOPs (such as photocatalysis) or membrane technologies.
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Affiliation(s)
- Ana R Ribeiro
- LCM - Laboratory of Catalysis and Materials - Associate Laboratory LSRE-LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - Olga C Nunes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Manuel F R Pereira
- LCM - Laboratory of Catalysis and Materials - Associate Laboratory LSRE-LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Adrián M T Silva
- LCM - Laboratory of Catalysis and Materials - Associate Laboratory LSRE-LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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10
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Oseghe EO, Ndungu PG, Jonnalagadda SB. Synthesis of mesoporous Mn/TiO2 nanocomposites and investigating the photocatalytic properties in aqueous systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:211-22. [PMID: 25060314 DOI: 10.1007/s11356-014-3356-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 07/17/2014] [Indexed: 05/24/2023]
Abstract
Mesoporous 20 wt% Mn/TiO2 nanocomposites were synthesized adopting modified sol-gel method at different pH (pH = 2, 7 and 11) conditions and calcined at 400 °C. Based on the characteristics of the 20 wt% Mn/TiO2 nanocomposites synthesized at pH 11, same procedure was adopted for the synthesis of different wt% Mn/TiO2. The nanocomposite samples and their surface properties were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), mapping, inductively coupled plasma optical emission spectrometry (ICP-OES), Fourier transform infrared (FTIR), and fluorescence spectrometry. The nanocomposites existed in the anatase phase of TiO2 with no peak assigned to Mn on the diffractogram. The photocatalytic activities of the materials were evaluated by monitoring degradation of a model dye (methylene blue (MB)) in presence of visible light and ozone. The nanocomposite synthesized under neutral condition (pH = 7) exhibited the best photocatalytic activity resulting from its relatively smaller crystal size (5.98 nm) and larger pore volume (0.30 cm(3)/g). One percentage of weight Mn/TiO2 showed 100% decolouration of MB in the presence of O3 after 100 min.
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Affiliation(s)
- Ekemena Oghenovoh Oseghe
- School of Chemistry and Physics, University of Kwa-Zulu Natal, Westville Campus, Private Bag X 54001, Durban, 4000, South Africa
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