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quantum yield of contaminant

Li Wang, Gang Wang, Congdi Shang, Rui Kang, Yu Fang
A naphthalimide-based low-molecular mass fluorophore (NA) was designed and synthesized by introducing an azetidine unit onto the aromatic ring of the compound as an electron-donating structure, and a hydrophilic (2-(2-aminoethylamino)ethanol) moiety into the 'N-imide site' of the core structure. UV-vis absorption and fluorescence measurements revealed that the fluorophore is soluble in water, and shows a fluorescent quantum yield of ~20% and lifetime of ~3.7 ns in the solvent within a wide pH range. Moreover, the fluorescence emission and anisotropy of the fluorophore as produced are both dependent upon the viscosity and polarity of the medium...
September 19, 2017: ACS Applied Materials & Interfaces
Dorota Jarmużek, Tomasz Pedzinski, Marcin Hoffmann, Tomasz Siodła, Kinga Salus, Donata Pluskota-Karwatka
Fluvastatin (FLV) belongs to the group of compounds referred to as statins, also known as 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors. Statins act as cholesterol-lowering agents and are among the most frequently prescribed drugs. They upregulate low-density lipoprotein receptors in the liver by binding to the active site of HMG-CoA reductase, which is the key enzyme in cholesterol biosynthesis. Statins have been detected as contaminants in natural waters and are susceptible to degradation upon exposure to light...
August 23, 2017: Physical Chemistry Chemical Physics: PCCP
Marcela Prado Silva, Arlen Mabel Lastre-Acosta, Simón Mostafa, Garrett McKay, Karl G Linden, Fernando L Rosario-Ortiz, Antonio Carlos Silva Costa Teixeira
Singlet oxygen ((1)O2), hydroxyl radicals ((•)OH), and excited triplet states of organic matter ((3)OM(*)) play a key role in the degradation of pollutants in aquatic environments. The formation rates and quantum yields (Φ) of these reactive intermediates (RI) through photosensitized reactions of dissolved organic matter (DOM) have been reported in the literature for decades. Urban biowaste-derived substances (UW-BOS), a form of organic matter derived from vegetative and urban waste, have recently been shown to be efficient sensitizers in the photo-degradation of different contaminants...
June 23, 2017: Environmental Science and Pollution Research International
Jason L J Dearling, Alan B Packard
BACKGROUND: Measurement of trace metal contamination is critical in the production of radiometals, such as 64Cu, for protein labeling. ICP-MS provides these data with high sensitivity and high specificity, but at high (instrument) cost. TETA (1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid) titration provides high sensitivity at low cost but with low specificity. A method that allowed the measurement of trace metals with high sensitivity but also at relatively low cost would, therefore, be very useful in the development of new radiometal production methods...
January 25, 2017: Current Radiopharmaceuticals
Andrew C Maizel, Christina K Remucal
The photochemical production of reactive species, such as triplet dissolved organic matter ((3)DOM) and singlet oxygen ((1)O2), contributes to the degradation of aquatic contaminants and is related to an array of DOM structural characteristics, notably molecular weight. In order to relate DOM molecular weight, optical properties, and reactive species production, Suwannee River (SRFA) and Pony Lake fulvic acid (PLFA) isolates are fractionated by sequential ultrafiltration, and the resultant fractions are evaluated in terms of molecular composition and photochemical reactivity...
February 21, 2017: Environmental Science & Technology
Noël J Diepens, Evelyne Buffan-Dubau, Hélène Budzinski, Jean Kallerhoff, Georges Merlina, Jérome Silvestre, Isabelle Auby, Nathalie Tapie, Arnaud Elger
Worldwide seagrass declines have been observed due to multiple stressors. One of them is the mixture of pesticides used in intensive agriculture and boat antifouling paints in coastal areas. Effects of mixture toxicity are complex and poorly understood. However, consideration of mixture toxicity is more realistic and ecologically relevant for environmental risk assessment (ERA). The first aim of this study was to determine short-term effects of realistic herbicide mixture exposure on physiological endpoints of Zostera noltei...
March 2017: Environmental Pollution
Sadegh Askari, Atta Ul Haq, Manuel Macias-Montero, Igor Levchenko, Fengjiao Yu, Wuzong Zhou, Kostya Ken Ostrikov, Paul Maguire, Vladimir Svrcek, Davide Mariotti
Highly size-controllable synthesis of free-standing perfectly crystalline silicon carbide nanocrystals has been achieved for the first time through a plasma-based bottom-up process. This low-cost, scalable, ligand-free atmospheric pressure technique allows fabrication of ultra-small (down to 1.5 nm) nanocrystals with very low level of surface contamination, leading to fundamental insights into optical properties of the nanocrystals. This is also confirmed by their exceptional photoluminescence emission yield enhanced by more than 5 times by reducing the nanocrystals sizes in the range of 1-5 nm, which is attributed to quantum confinement in ultra-small nanocrystals...
October 6, 2016: Nanoscale
Jinhua Zhang, Jie Wang, Jia Feng, Junping Lv, Jin Cai, Qi Liu, Shulian Xie
1,4-Dichlorobenzene (1,4-DCB) is a common organic contaminant in water. To determine the effects of this contaminant on photosynthesis in the freshwater alga Chlorella pyrenoidosa, algal cells were treated with 1,4-DCB at different concentrations for various times, and their photosynthetic pigment contents and chlorophyll fluorescence traits were analyzed. The results showed that 1,4-DCB exerted toxic effects on photosynthesis in C. pyrenoidosa, especially at concentrations exceeding 10 mg/L. The inhibitory effects of 1,4-DCB were time- and concentration-dependent...
September 2016: Environmental Monitoring and Assessment
R K Dutta, Ambika Kumar
Detection of ultratrace levels of aqueous uranyl ions without using sophisticated analytical instrumentation and a tedious sample preparation method is a challenge for environmental monitoring and mitigation. Here we present a novel yet simple analytical method for highly sensitive and specific detection of uranyl ions via photoluminescence quenching of CdS quantum dots. We have demonstrated a new approach for synthesizing highly water-soluble and strong photoluminescence-emitting CdS quantum dots (i.e., CdS-MAA and CdS-MAA-TU) of sizes less than 3 nm...
September 20, 2016: Analytical Chemistry
C Escapa, R N Coimbra, S Paniagua, A I García, M Otero
The biomass growth, pharmaceutical removal and light conversion efficiency of Chlorella sorokiniana under the presence of paracetamol (PC) and salicylic acid (SaC) were assessed and compared at two different concentrations of these pharmaceuticals (I: 25 mg l(-1), II: 250 mg l(-1)). Microalgae were resistant to these concentrations and, moreover, their growth was significantly stimulated (p ≤ 0.05) under these drugs (biomass concentration increased above 33% PCI, 35% SaCI, 13% PCII and 45% SaCII, as compared with the respective positive controls)...
July 12, 2016: Journal of Environmental Management
Izaskun Llagostera, Daniel Cervantes, Neus Sanmartí, Javier Romero, Marta Pérez
Seagrasses form some of the most important coastal habitats. They may be negatively affected by trace metal contamination in certain coastal areas. In this study we experimentally assessed selected morphological and physiological traits of the seagrass Cymodocea nodosa, with increasing concentrations of copper (Cu) under controlled laboratory conditions. Short term (21 days) sub-lethal effects such as decreased maximum quantum yield, increased leaf necrosis and decreased shoot growth and shoot recruitment were clearly observed at the highest Cu exposure (5 mg L(-1)), while the effects were weaker at the intermediate concentration (2...
September 2016: Bulletin of Environmental Contamination and Toxicology
Habib-Ur-Rehman Athar, Sarah Ambreen, Muhammad Javed, Mehwish Hina, Sumaira Rasul, Zafar Ullah Zafar, Hamid Manzoor, Chukwuma C Ogbaga, Muhammad Afzal, Fahad Al-Qurainy, Muhammad Ashraf
Maize tolerance potential to oil pollution was assessed by growing Zea mays in soil contaminated with varying levels of crude oil (0, 2.5 and 5.0 % v/w basis). Crude oil contamination reduced soil microflora which may be beneficial to plant growth. It was observed that oil pollution caused a remarkable decrease in biomass, leaf water potential, turgor potential, photosynthetic pigments, quantum yield of photosystem II (PSII) (Fv/Fm), net CO2 assimilation rate, leaf nitrogen and total free amino acids. Gas exchange characteristics suggested that reduction in photosynthetic rate was mainly due to metabolic limitations...
September 2016: Environmental Science and Pollution Research International
Miriam Ahuactzin-Pérez, Saúl Tlecuitl-Beristain, Jorge García-Dávila, Manuel González-Pérez, María Concepción Gutiérrez-Ruíz, Carmen Sánchez
Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the manufacture of plastics, and it is an environmental contaminant. The specific growth rate (μ), maximum biomass (Xmax), biodegradation constant of DEHP (k), half-life (t1/2) of DEHP biodegradation and removal efficiency of DEHP, esterase and laccase specific activities, and enzymatic yield parameters were evaluated for Fusarium culmorum grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000mg/L). The greatest μ and the largest Xmax occurred in media supplemented with 1000mg of DEHP/L...
October 1, 2016: Science of the Total Environment
Andrew J McCabe, William A Arnold
The hydrology and water chemistry of prairie pothole wetlands vary spatially and temporally, on annual and decadal timescales. Pesticide contamination of wetlands arising from agricultural activities is a foremost concern. Photochemical reactions are important in the natural attenuation of pesticides and may be important in limiting ecological and human exposure. Little is known, however, about the variable influence of wetland water chemistry on indirect photochemistry. In this study, seasonal water samples were collected from seven sites throughout the prairie pothole region over three years to understand the spatiotemporal dynamics of reactive intermediate photoproduction...
July 2016: Chemosphere
Xin Jin, Shanshan Qiu, Ke Wu, Mingyun Jia, Fang Wang, Chenggang Gu, Aiqian Zhang, Xin Jiang
The extensive usage of OTC and Cu(2+) in livestock and poultry industry caused high residues in natural environment. Co-contamination of OTC and Cu(2+) was a considerable environmental problem in surface waters. In this study, Cu(2+) mediated direct photolysis of OTC was studied. Cu(2+) chelating with OTC was found to greatly inhibit OTC photodegradation. To reveal the chelation mechanism of OTC-Cu complexes, multiple methods including UV-Vis absorption spectra, Infrared (IR) spectra, mass spectroscopy, and density functional theoretical (DFT) modeling were performed...
July 2016: Environmental Pollution
Linke Ge, Jun Li, Guangshui Na, Chang-Er Chen, Cheng Huo, Peng Zhang, Ziwei Yao
Hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) are derived from hydroxylated PAHs as contaminants of emerging concern. They are ubiquitous in the aqueous and atmospheric environments and may exist in the polar snow and ice, which urges new insights into their environmental transformation, especially in ice. In present study the simulated-solar (λ > 290 nm) photodegradation kinetics, products and pathways of four OH-PAHs (9-Hydroxyfluorene, 2-Hydroxyfluorene, 1-Hydroxypyrene and 9-Hydroxyphenanthrene) in ice were investigated, and the corresponding implications for the polar areas were explored...
July 2016: Chemosphere
Maria Celeste Dias, José Moutinho-Pereira, Carlos Correia, Cristina Monteiro, Márcia Araújo, Wolfgang Brüggemann, Conceição Santos
This research aims at identifying the main deleterious effects of Cr(VI) on the photosynthetic apparatus and at selecting the most sensitive endpoints related to photosynthesis. To achieve this goal, we used lettuce (Lactuca sativa), a sensible ecotoxicological crop model. Three-week-old plants were exposed to 0, 50, 150 and 200 mg L(-1) of Cr(VI). These concentrations ranged from levels admitted in irrigation waters to values found in several Cr industry effluents and heavily contaminated environments. After 30 days of exposure, plants accumulated Cr preferably in roots and showed nutritional impairment, with decreases of K, Mg, Fe and Zn in both roots and leaves...
August 2016: Environmental Science and Pollution Research International
Wen-Long Wang, Qian-Yuan Wu, Nan Huang, Ting Wang, Hong-Ying Hu
For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic...
July 1, 2016: Water Research
Muhammad Iqbal, Tapas K Purkait, Greg G Goss, James R Bolton, Mohamed Gamal El-Din, Jonathan G C Veinot
Surface-engineered amphiphilic polymer-coated silicon nanoparticles (SiNPs) were employed as photocatalysts to capture and degrade a model organic contaminant (methanol) in water. This study represents the first time SiNPs have been employed in the initiation of advanced oxidation processes that are commonly used to degrade organic constituents in industrial wastewaters. The quantum yield of photocatalytic methanol oxidation and the corresponding yield factor for the generation of active OH radicals are reported...
May 24, 2016: ACS Nano
Juri Bolobajev, Marina Trapido, Anna Goi
Doxycycline plays a key role in Fe(III)-to-Fe(II) redox cycling and therefore in controlling the overall reaction rate of the Fenton-based process (H2O2/Fe(III)). This highlights the autocatalytic profile of doxycycline degradation. Ferric iron reduction in the presence of doxycycline relied on doxycycline-to-Fe(III) complex formation with an ensuing reductive release of Fe(II). The lower ratio of OH-to-contaminant in an initial H2O2/Fe(III) oxidation step than in that of classical Fenton (H2O2/Fe(II)) decreased the doxycycline degradation rate...
June 2016: Chemosphere
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