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Sample records for biological uv oxidation

  1. Treatment of Phenolic Wastewater by Combining UV-Fenton Oxidation with Biological Oxidation%UV-Fenton氧化-生化法联合处理含酚废水

    Institute of Scientific and Technical Information of China (English)

    刘琼玉; 刘君侠; 刘延湘

    2011-01-01

    Phenolic wastewater was treated by combined process of UV-Fenton oxidation-biological oxidation. Treatment efficiency of phenolic wastewater by single UV-Fenton oxidation,single biological oxidation and combined process were compared. Results indicated that effective degradation of coal-gas phenolic wastewater was observed by UV-Fenton process,but complete degradation of phenolic wastewater need to consume large numbers of H2O2 with high cost,which is uneconomical. Direct biological oxidation cannot efficient treat coal-gas phenolic wastewater due to low ratio of BODs/COD.UV-Fenton preoxidation is effective at enhancing biodegradability of coal-gas phenolic wastewater,and the biodegradability of wastewater enhanced obviously with increasing dosage of H2O2 in UV-Fenton preoxidation. When H2O2 was added only 21.6% of stoichiometric calculated quantities,COD would reduce from 1,306 mg/L to 121 mg/L and phenol reduced from 193.5 mg/L to 0.43 mg/L,both COD and phenol of coal-gas phenolic wastewater can satisfy national control standard by combined process of UV-Fenton oxidation-biological oxidation. Experimental results showed that 75% H2O2 were saved by combined process of UV-Fenton oxidation-biological oxidation, comparing with single UV-Fenton process.%采用UV-Fenton氧化-生化法联合处理煤气含酚废水,比较了单独UV-Fenton氧化法、单独生化法和UV-Fenton氧化-生化法联合工艺对煤气含酚废水的处理效果.结果表明,UV-Fenton氧化体系可有效降解含酚废水,但废水完全降解所需的H2O2用量大,处理成本高.煤气含酚废水的BOD5/COD比值较低,直接采用生化处理的效果不理想,通过UV-Fenton氧化预处理可明显提高煤气含酚废水的生物降解性,随着H2O2投加量的增加,废水的BOD5/COD比值逐渐增大,生物降解性明显增强.当UV/Fenton氧化过程H2O2用量为21.6%理论投加量时,采用UV-Fenton氧化-生化法联合工艺可使煤气含酚废水的COD由1306mg

  2. Biological assessment of bisphenol A degradation in water following direct photolysis and UV advanced oxidation.

    Science.gov (United States)

    Chen, Pei-Jen; Linden, Karl G; Hinton, David E; Kashiwada, Shosaku; Rosenfeldt, Erik J; Kullman, Seth W

    2006-11-01

    Endocrine disrupting compounds (EDCs) are exogenous environmental chemicals that can interfere with normal hormone function and present a potential threat to both environmental and human health. The fate, distribution and degradation of EDCs is a subject of considerable investigation. To date, several studies have demonstrated that conventional water treatment processes are ineffective for removal of most EDCs and in some instances produce multiple unknown transformation products. In this study we have investigated the use of direct photolysis with low-pressure (LP) Hg UV lamps and UV+hydrogen peroxide (H(2)O(2)) advanced oxidation process (AOP) for the degradation of a prototypic endocrine disrupter, bisphenol A (BPA), in laboratory water. Removal rates of BPA and formation of degradation products were determined by high performance liquid chromatography (HPLC) analysis. Changes in estrogenic activity were evaluated using both in vitro yeast estrogen screen (YES) and in vivo vitellogenin (VTG) assays with Japanese medaka fish (Oryzias latipes). Our results demonstrate that UV alone did not effectively degrade BPA. However, UV in combination with H(2)O(2) significantly removed BPA parent compound and aqueous estrogenic activity in vitro and in vivo. Removal rates of in vivo estrogenic activity were significantly lower than those observed in vitro, demonstrating differential sensitivities of these bioassays and that certain UV/AOP metabolites may retain estrogenic activity. Furthermore, the UV/H(2)O(2) AOP was effective for reducing larval lethality in treated BPA solutions, suggesting BPA degradation occurred and that the degradation process did not result in the production of acutely toxic intermediates.

  3. UV/Fenton联合生物接触氧化工艺去除废水中LAS应用研究%Application Research of LAS in Wastewater Removal of UV/Fenton Combined with Biological Contact Oxidation Process

    Institute of Scientific and Technical Information of China (English)

    徐晓毅

    2015-01-01

    针对直链烷基苯磺酸钠(LAS)的降解机理,选择UV/Fenton法联合接触生物氧化法处理LAS高盐废水,结果显示:UV/Fenton工艺降解效果明显优于Fenton工艺,对于含LAS污染物存在一个H2O2和FeSO4最佳投加量,采取H2O2分批投加的方式确实能够提高处理效果.%In view of linear alkylbenzene sulfonate (LAS)degradation mechanism,the UV/Fenton method combined with biological contact oxidation process were selected to treat LAS wastewater with high salinity.The results showed that the UV/Fenton process degradation effect was obviously better than that of the Fenton process. LAS pollutants had the best dosage of H2O2 and FeSO4.The UV/Fenton process with H2O2 batch addition way could improve treatment effects.

  4. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E.; Thomalla, E.; Koepke, P. [Munich Univ. (Germany). Meteorological Inst.

    1995-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  5. Pilot-scale UV/H2O2 advanced oxidation process for surface water treatment and downstream biological treatment: effects on natural organic matter characteristics and DBP formation potential.

    Science.gov (United States)

    Sarathya, Siva R; Stefan, Mihaela I; Royce, Alan; Mohseni, M

    2011-12-01

    The effects of the advanced oxidation process (AOP) of ultraviolet radiation in combination with hydrogen peroxide (UV/H2O2) on the structure and biodegradability of dissolved natural organic matter (NOM) and on the formation of disinfection by-products (DBPs) through the post-UV/H2O2 chlorination were investigated using UV reactors equipped with either low-pressure amalgam lamps or medium-pressure mercury vapour lamps. With electrical energy doses and H2O2 concentrations typically applied in full-scale UV systems for water remediation, the UV/H2O2 AOP partially oxidized NOM, reducing its degree of aromaticity and leading to an increase in the level of biodegradable species. Also, when combined with a downstream biological activated carbon (BAC) filter, UV/H2O2 AOP reduced the formation of DBPs by up to 60% for trihalomethanes and 75% for haloacetic acids. Biological activated carbon was also shown to effectively remove biodegradable by-products and residual H2O2.

  6. Removal of gaseous toluene by the combination of photocatalytic oxidation under complex light irradiation of UV and visible light and biological process.

    Science.gov (United States)

    Wei, Zaishan; Sun, Jianliang; Xie, Zhirong; Liang, Mingyan; Chen, Shangzhi

    2010-05-15

    Photocatalysis is a promising technology for treatment of gaseous waste; its disadvantages, however, include causing secondary pollution. Biofiltration has been known as an efficient technology for treatment volatile organic compounds (VOCs) at low cost of maintenance, and produces harmless by-products; its disadvantages, include large volume of bioreactor and slow adaptation to fluctuating concentrations in waste gas. A bench scale system integrated with a photocatalytic oxidation and a biofilter unit for the treatment of gases containing toluene was investigated. The integrated system can effectively oxidize toluene with high removal efficiency. The photocatalytic activity of N-TiO(2)/zeolite was evaluated by the decomposition of toluene in air under UV and visible light (VL) illumination. The N-TiO(2)/zeolite has more photocatalytic activity under complex light irradiation of UV and visible light for toluene removal than that of pure TiO(2)/zeolite under UV or visible light irradiation. N-TiO(2)/zeolite was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectrum analysis (XPS), Fourier transform infrared spectroscopy (FT-IR), and as-obtained products were identified by means of gas chromatography/mass spectrometry (GC/MS). Results revealed that the photocatalyst was porous and was high photoactive for mineralizing toluene. The high activity can be attributed to the results of the synergetic effects of strong UV and visible light absorption, surface hydroxyl groups. The photocatalytic degradation reaction of toluene with the N-TiO(2)/zeolite follows Langmuir-Hinshelwood kinetics. Toluene biodegradation rate matches enzymatic oxidation kinetics model.

  7. Biological assessments of a mixture of endocrine disruptors at environmentally relevant concentrations in water following UV/H{sub 2}O{sub 2} oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P.-J. [Department of Civil and Environmental Engineering, Duke University (United States); Integrated Toxicology Program, Nicolas School of Environment and Earth Science, Duke University (United States); Rosenfeldt, Erik J. [Department of Civil and Environmental Engineering, Duke University (United States); Kullman, Seth W. [Integrated Toxicology Program, Nicolas School of Environment and Earth Science, Duke University (United States); Hinton, David E. [Integrated Toxicology Program, Nicolas School of Environment and Earth Science, Duke University (United States); Linden, Karl G. [Department of Civil and Environmental Engineering, Duke University (United States)]. E-mail: kglinden@duke.edu

    2007-04-15

    Numerous studies have investigated degradation of individual endocrine disrupting compounds (EDCs) in lab or natural waters. However, natural variations in water matrices and mixtures of EDCs in the environment may confound analysis of the treatment efficiency. Because chemical based analytical methods cannot represent the combined or synergistic activities between water quality parameters and/or the EDC mixtures at environmentally relevant concentrations ({mu}g L{sup -1}-ng L{sup -1}), bioanalytical assessments of residual estrogenic activity in treated water were used to evaluate the performance of the UV based advanced oxidation process for estrogenic contaminants in water. Four EDCs including estradiol (E{sub 2}), ethinyl estradiol (EE{sub 2}), bisphenol-A (BPA) and nonylphenol (NP) were spiked individually or as a mixture at {mu}g L{sup -1}-ng L{sup -1} in laboratory or natural river water. The removal rates of estrogenic activity were quantitatively evaluated by in vitro yeast estrogen screen (YES) and in vivo Vitellogenin (VTG) assays with Japanese medaka fish (Oryzias latipes). UV in combination with 10 ppm H{sub 2}O{sub 2} as an oxidation process was capable of decreasing in vitro and in vivo estrogenic activity, however, in vivo estrogenic activity of the EDC mixture in natural water was not completely removed at UV fluence up to 2000 mJ cm{sup -2}. The removal rates of in vitro estrogenic activity of the EDC mixtures were lower than those observed for single compounds, and slower in natural waters, likely due to lower steady-state concentrations of hydroxyl radicals ({center_dot}OH) in the presence of {center_dot}OH scavengers from the water matrix and EDC mixture.

  8. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    KAUST Repository

    Caputo, Fanny

    2015-08-20

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields. © The Royal Society of Chemistry 2015.

  9. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    Science.gov (United States)

    Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

    2015-09-01

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

  10. Advanced UV Source for Biological Agent Destruction

    Science.gov (United States)

    2006-01-01

    G., “ Photocatalysis Under Periodic Illumination, Ph.D. Thesis, California Institute of Technology, September 24, 2001.) 6 Wavelength (nm) 175...phosphate MDCP Methyl salicylate Figure 2.4-1. UV absorption cross sections for various chemical agents and simulants. Titanium dioxide ( TiO2 ) is one

  11. Response of biological uv dosimeters to the simulated extraterrestrial uv radiation

    Science.gov (United States)

    Bérces, A.; Rontó, G.; Kerékgyártó, T.; Kovács, G.; Lammer, H.

    In the Laboratory polycrystalline uracil thin layer and bacteriophage T7 detectors have been developed for UV dosimetry on the EarthSs surface. Exponential response of the uracil polycrystal has been detected both by absorption spectroscopy and measurements of the refractive index under the influence of terrestrial solar radiation or using UV-C sources. In UV biological dosimetry the UV dose scale is additive starting at a value of zero according to the definition of CIE (Technical Report TC-6-18). The biological dose can be defined by a measured end-effect. In our dosimeters (phage T7 and uracil dosimeter) exposed to natural (terrestrial) UV radiation the proportion of pyrimidin photoproducts among the total photoproducts is smaller than 0.1 and the linear correlation between the biological and physical dose is higher than 0.9. According to the experimental data this linear relationship is often not valid. We observed that UV radiation did not only induce dimerisation but shorter wavelengths caused monomerisation of pyrimidin dimers. Performing the irradiation in oxygen free environment and using a Deuterium lamp as UV source, we could increase monomerisation against dimerisation thus the DNA-based dosimetrySs additivity rule is not fulfilled in these conditions. In this study we will demonstrate those non-linear experiments which constitute the basis of our biological experiments on the International Space Station.

  12. Combined Application of UV Photolysis and Ozonation with Biological Aerating Filter in Tertiary Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Zhaoqian Jing

    2012-01-01

    Full Text Available To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF. The results indicated that UV photolysis could not remove much COD (chemical oxygen demand, and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3, COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD and biodegradability greatly. Proportion of organic compounds with molecular weight (MW <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3 oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3 oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.

  13. Ciprofloxacin oxidation by UV-C activated peroxymonosulfate in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Mahdi-Ahmed, Moussa; Chiron, Serge, E-mail: Serge.Chiron@msem.univ-montp2.fr

    2014-01-30

    Highlights: • UV/PMS more efficient than UV/H{sub 2}O{sub 2} for ciprofloxacin removal in wastewater. • PMS decomposition into sulfate radical was activated by bicarbonate ions. • CIP degradation pathways elucidation support sulfate radical attacks as a main route. • Sulfate radical generation allows for CIP antibacterial activity elimination. -- Abstract: This work aimed at demonstrating the advantages to use sulfate radical anion for eliminating ciprofloxacin residues from treated domestic wastewater by comparing three UV-254 nm based advanced oxidation processes: UV/persulfate (PDS), UV/peroxymonosulfate (PMS) and UV/H{sub 2}O{sub 2}. In distilled water, the order of efficiency was UV/PDS > UV/PMS > UV/H{sub 2}O{sub 2} while in wastewater, the most efficient process was UV/PMS followed by UV/PDS and UV/H{sub 2}O{sub 2} mainly because PMS decomposition into sulfate radical anion was activated by bicarbonate ions. CIP was fully degraded in wastewater at pH 7 in 60 min for a [PMS]/[CIP] molar ratio of 20. Nine transformation products were identified by liquid chromatography–high resolution-mass spectrometry allowing for the establishment of degradation pathways in the UV/PMS system. Sulfate radical anion attacks prompted transformations at the piperazinyl ring through a one electron oxidation mechanism as a major pathway while hydroxyl radical attacks were mainly responsible for quinolone moiety transformations as a minor pathway. Sulfate radical anion generation has made UV/PMS a kinetically effective process in removing ciprofloxacin from wastewater with the elimination of ciprofloxacin antibacterial activity.

  14. Coupling ARB-based biological and photochemical (UV/TiO2 and UV/S2O8(2-)) techniques to deal with sanitary landfill leachate.

    Science.gov (United States)

    Hassan, Muhammad; Wang, Xiaoyuan; Wang, Fei; Wu, Dong; Hussain, Asif; Xie, Bing

    2016-09-12

    The aim of this study was to provide an alternative way to remove bio-refractory organics and ammonical-nitrogen from mature municipal solid waste (MSW) landfill leachate by combining biological and photochemical processes. To achieve this objective, the effectiveness of anoxic aged refuse-based bioreactor (ARB) for biological leachate pretreatment followed by Advanced Oxidation Processes (AOPs) by heterogeneous photocatalysis (TiO2/UV) and persulfate (S2O8(2-)) oxidation were tested. The results obtained after ARB based pre-treatment demonstrated a mean 72%, 81% and 92% degradation of COD, NH4N and TN, respectively. However, this treated leachate cannot be discharged without another treatment; hence, it was further treated by UV-mediated TiO2 photocatalysis and S2O8(2-) oxidation. An average 82% of COD was abated at optimum condition (1gL(-1) TiO2; pH 5) whereas, using an optimum 1.5gL(-1) persulfate at pH 5, 81% COD reduction occurred. Acidic and alkaline pH favored COD and NH4N removal respectively. The results of this study demonstrated that coupling ARB with AOPs is potentially applicable process to deal with bio-recalcitrant compounds present in mature landfill leachate.

  15. Validation of an Austrian forecasting model for biologically effective UV radiation (UV index); Validierung des oesterreichischen Vorhersagemodells fuer die biologisch-effektive UV Strahlung (UV Index)

    Energy Technology Data Exchange (ETDEWEB)

    Schauberger, G.; Schmalwieser, A. [Veterinaermedizinische Univ., Vienna (Austria). Inst. fuer Medizinische Physik

    1999-07-01

    Since October 1995 there has been an Austrian forecasting service for the next day's UV index for the three model domains Austria, Europe and world. This forecasting model uses spectral irradiation intensity data measured for 16 specific wavelengths, taking into account solar altitude, height above sea level and atmospheric ozone concentration. Weighting spectral irradiation intensity according to the spectral erythematous effect curve yields a measure of biologically effective UV radiation, and subsequent normalisation with respect to 25 mW{sub biol}/m-2 relates the result to the dimension figure for the UV index. The model has been validated by means of data obtained by continuous measurement with Robertson-Berger measuring devices (site of the Vienna Veterinary Hospital: 48 15 15.47'N; 16 25.98E; elevation 153 amsl). The spectral sensitivity of these instruments is approximately the same as that of the human skin to reddening. Combining the UV index with the expected UV dose for the day permits issuing recommendations for the most suitable sun protection factor in sunblock creams as a function of users' photobiological skin type. Users of the UV index are expected to have enough personal initiative to select the UV index that most closely corresponds to their local population situation. According to the principles of UV radiation protection the performance of the model is considered poor if the measured UV index is greater than the forecast index. This happens in approx. 12% of all cases. The error frequency of positive errors (forecast values greater than measured values) reflects the degree to which extinction of UV radiation through the population occurs, as the present model does not take this factor into account. [German] Seit Oktober 1995 wird in Oesterreich taeglich eine Prognose des UV-Index fuer die drei Modelldomaenen: Oesterreich, Europa und weltweit, geltend fuer den darauf folgenden Tag, erstellt. Das oesterreichische Prognosemodell

  16. O3/UV与生化组合处理印染废水%Treatment of dyeing wastewater by hybrid processes of biological oxidation and O3/UV oxidation

    Institute of Scientific and Technical Information of China (English)

    李兵宇; 刘万生; 赵伟荣; 周威明; 吴忠标

    2005-01-01

    在半序批式反应器中进行印染废水的O3/UV氧化,间歇及连续生化反应器中进行生化处理,以COD去除率、BOD/COD、臭氧消耗系数和臭氧消耗量等指标,考察O3/UV与生化组合处理印染废水的工艺.印染废水用"生化-物化-O3/UV"法处理,其出水COD、色度指标可完全满足GB 4287-1992的一级排放要求,还可以降低臭氧消耗量;而 O3/UV-生化-物化"法处理,出水的COD不能满足.

  17. UV irradiation and UV-H₂O₂ advanced oxidation of the roxarsone and nitarsone organoarsenicals.

    Science.gov (United States)

    Adak, Asok; Mangalgiri, Kiranmayi P; Lee, Jessica; Blaney, Lee

    2015-03-01

    Roxarsone (ROX) and nitarsone (NIT) are used as additives in animal feeding operations and have been detected in animal manure, agricultural retention ponds, and adjacent surface waters. This work investigates treatment of organoarsenicals using UV-based treatment processes, namely UV irradiation at 253.7 nm and the UV-H2O2 advanced oxidation process. The apparent molar absorptivity was mapped for ROX and NIT across pH and wavelength. For UV irradiation at 253.7 nm, the fluence-based pseudo-first order rate constant (kp(')) and effective quantum yield (Φ) for ROX were 8.10-29.7 × 10(-5) cm(2)/mJ and 2.34-8.37 × 10(-3) mol/E, respectively; the corresponding constants were slightly lower for NIT. The observed rate constants are higher during advanced oxidation (e.g., kp,ROX(')=3.92(±0.19)-217(±48) × 10(-4) cm(2)/mJ). Second order rate constants for organoarsenical transformation by hydroxyl radicals were determined to be 3.40(±0.45) × 10(9) and 8.28(±0.49) × 10(8) M(-1)s(-1) for ROX and NIT, respectively. Solution pH and nitrate concentration did not significantly impact ROX transformation during advanced oxidation; however, bicarbonate and dissolved organic matter from chicken litter reduced ROX transformation through hydroxyl radical scavenging. Inorganic arsenic was the predominant transformation product of ROX during UV-H2O2 treatment.

  18. DLR-Biofilm - a biological weighting UV-dosimeter in medical application; Der DLR-Biofilm - ein biologisch wichtendes UV-Dosimeter in der medizinischen Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, K.; Rettberg, P.; Horneck, G.J [Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany). Inst. fuer Luft- und Raumfahrtmedizin; Schneider, L.; Wlaschek, M.; Scharffetter-Kochanek, K. [Universitaetsklinikum Koeln, Klinik und Poliklinik fuer Dermatologie und Venerologie, Koeln (Germany)

    2004-07-01

    A prototype of an optoelectronic-biological UV dosimeter was developed as a combination of DLR-Biofilm and the optoelectronic UV sensor X20001. The device was used to quantify the individual exposure during UV therapy. The obtained biologically weighted doses were compared to the UV dose given by the manufacturer of the UV therapy lamp. The endogenous parameter 8-Isoprostan obtained directly from the skin of probands showed good correlation with the measured biologically weighted dose. (orig.)

  19. Studies of biological effects of fluoride stannous and UV short in Escherichia coli BH110

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da C, R., E-mail: rogercosta1@hotmail.com [Federal Institute of Education, Science and Technology of Goias, Campus Uruacu, Rua Formosa Qd 28 e 29, Loteamento Santana, 76400-000 Uruacu, Goias (Brazil)

    2015-10-15

    Full text: The amount of UV rays on the Earth's surface has increased due to depletion of the ozone layer, and this has worried society, since these radiation although not considered ionizing can cause damage to biological membrane and especially to DNA. The DNA has cell repair mechanisms that can work in lesions caused by electromagnetic radiation such as ultraviolet -short (UV C)and agents causing oxidative stress, such as tin salts. Among the repair mechanisms can highlight the adaptive repair, which consists of smaller doses to cells pre-exposure of an oxidizing agent, and when these cells are exposed to larger doses of the agent even if there is a reduction in mortality rate which leads to complete that repair mechanisms are activated in the pre-exposure reducing cell mortality. Several publications have shown the genotoxic effects of stannous salts such as stannous fluoride (SnF{sub 2}), which shows the importance of the study, since these salts are widely used in industry as components in toothpastes and mouthwashes. So we check whether pretreatment with UV C is able to induce adaptive response reducing the cytotoxic effects caused by exposure of the strains to SnF{sub 2}. We use a strain of Escherichia coli BH110 (BH110 E. coli) deficient in three genes (fpg, nfo and xth) involved in the excision repair bases. To verify the induction of adaptive response to strain BH110 was exposed to various doses of UV C and then treated with SnF{sub 2} a concentration of 110 u M. Our results showed that the LD10 of strain BH110 is 20 J/m{sup 2} and pre-treatment with UV C does not seem to induce adaptive repair in BH110 strains. (Author)

  20. UV Irradiation Chlorine Dioxide Photocatalytic Oxidation of Simulated Fuchsine Wastewater by UV-Vis and Online FTIR Spectrophotometric Method

    OpenAIRE

    Jie Liu; Chunlei Huai; Na Li; Xiaomei Wang; Laishun Shi

    2012-01-01

    The photocatalyst TiO2/SiO2 was prepared and used for chlorine dioxide photocatalytic oxidation of simulated fuchsine wastewater under UV irradiation. The removal efficiency of fuchsine treated by photocatalytic oxidation process is higher than that of chemical oxidation process. By using UV-Vis and online FTIR analysis technique, the intermediates during the degradation process were obtained. The benzene ring in fuchsine was degraded into quinone and carboxylic acid and finally changed into ...

  1. Are UV photolysis and UV/H2O2 process efficient to treat estrogens in waters? Chemical and biological assessment at pilot scale.

    Science.gov (United States)

    Cédat, Bruno; de Brauer, Christine; Métivier, Hélène; Dumont, Nathalie; Tutundjan, Renaud

    2016-09-01

    In this study, UV based treatments were implemented at pilot scale to assess their ability to remove hormones from treated wastewater, especially with the view to equip small and medium size Wastewater Treatment Plants (WTPs). To this end, the degradation of a mixture of estrogenic hormones (Estrone (E1), β-Estradiol (E2), and 17α-Ethinyl Estradiol (EE2)) in waters by UV photolysis and UV/H2O2 process was investigated in real conditions. A particular attention was paid at designing a well validated laboratory scale pilot in order to optimise oxidant concentrations and UV fluence. A Low pressure lamp (254 nm) was used in a flow through commercial reactor. The effects of water matrices (drinking water and treated wastewater) and H2O2 concentrations (10, 40, and 90 mg/L) on the pilot efficiency were first determined. Only E1 could be partially degraded by UV photolysis whereas hormones were all well removed by UV/H2O2 process in both matrices. The second part of the study focused on a chemical and biological assessment of UV photolysis and UV/H2O2 process (30 and 50 mg/L). Degradation rate constants of hormones as well as changes in estrogenic activity (YES bioassay) and toxicity (Vibrio fischeri) were followed at the same time. UV photolysis could not remove neither estrogens nor estrogenic activity at relevant UV fluence in waters. However 80% of initial estrogenic compounds and estrogenic activity could be removed from treated wastewater by combining UV fluence of 423 and 520 mJ/cm(2) with 50 and 30 mg/L of H2O2, respectively. No high estrogenic or toxic by-products were detected by the two bioassays following UV photolysis or UV/H2O2 process. Operating costs were estimated for a full scale pilot. H2O2 was the major cost. By combining the appropriate concentration of H2O2 and UV fluence, it could be possible to design a cost effective treatment for treating estrogens in small and medium size WTPs.

  2. Blue and UV fluorescence of biological fluids and carbon nanodots

    Science.gov (United States)

    Kuznetsov, A.; Frorip, A.; Ots-Rosenberg, M.; Sünter, A.

    2013-11-01

    Comparative optical study of biofluids (serum, urine, hemodialysate) and carbon nanodots (CND) aqueous solutions has been done. Biofluids were collected from chronic kidney diseases patients (CKD Pts) as well as from normal controls (NCs). Sugar derived CND and oxidized graphene solutions were prepared and used. Fluorescence and excitation spectra have mainly been measured and compared for two sets of subjects. For both family of subjects typical fluorescence with parameters λexсmax/ λemmax = 320+/-5/420+/-5 nm is observed and has many analogeous properties. New effective method of additional similarity identification with use of aluminum salts Al2 (SO4)3, Al (N03)3 and AlCl3 is proposed. Aluminum ions induce the fluorescence band at 380 nm in all substances investigated. Plenty of similar features (12) in optical properties create a united platform for further investigation of the topic - the nature of endogenous near UV and visible fluorescence in biofluids and CND.

  3. Administration with Bushenkangshuai Tang alleviates UV irradiation- and oxidative stress-induced lifespan defects in nematode Caenorhabditis elegans

    Institute of Scientific and Technical Information of China (English)

    Qi RUI; Qin LU; Dayong WANG

    2009-01-01

    During normal metabolism, oxidative bypro-ducts will inevitably generate and damage molecules thereby impairing their biological functions, including the is a traditional Chinese medicine widely used for clini-cally treating premature ovarian failure. In the present study, BT administration at high concentrations signifi-cantly increased lifespan, slowed aging-related decline, and delayed accumulation of aging-related cellular damage in wild-type Caenorhabditis elegans. BT admin-istration could further largely alleviate the aging defects induced by UV and oxidative stresses, and BT administra-tion at different concentrations could largely rescue the aging defects in mev-1 mutant animals. The protective effects of BT administration on aging process were at least partially dependent on the Ins/IGF-like signaling pathway. Moreover, BT administration at different concentrations obviously altered the expression patterns of antioxidant genes and suppressed the severe stress responses induced by UV and oxidative stresses, suggesting that BT-induced tolerance to UV or oxidative stress might result from reactive oxygen species scavenging. BT administration during development was not necessarily a requirement for UV and oxidative stress resistance, and the concentrations of administrated BT examined were not toxic for nematodes. Therefore, BT administration could effectively retrieve the aging defects induced by UV irradiation and oxidative stress in Caenorhabditis elegans.

  4. Emerging micropollutant oxidation during disinfection processes using UV-C, UV-C/H2O2, UV-A/TiO2 and UV-A/TiO2/H2O2.

    Science.gov (United States)

    Pablos, Cristina; Marugán, Javier; van Grieken, Rafael; Serrano, Elena

    2013-03-01

    Regeneration of wastewater treatment plant effluents constitutes a solution to increase the availability of water resources in arid regions. Water reuse legislation imposes an exhaustive control of the microbiological quality of water in the operation of disinfection tertiary treatments. Additionally, recent reports have paid increasing attention to emerging micropollutants with potential biological effects even at trace level concentration. This work focuses on the evaluation of several photochemical technologies as disinfection processes with the aim of simultaneously achieving bacterial inactivation and oxidation of pharmaceuticals as examples of emerging micropollutants typically present in water and widely studied in the literature. UV-C-based processes show a high efficiency to inactivate bacteria. However, the bacterial damages are reversible and only when using H(2)O(2), bacterial reproduction is affected. Moreover, a complete elimination of pharmaceutical compounds was not achieved at the end of the inactivation process. In contrast, UV-A/TiO(2) required a longer irradiation time to inactivate bacteria but pharmaceuticals were completely removed along the process. In addition, its oxidation mechanism, based on hydroxyl radicals (OH), leads to irreversible bacterial damages, not requiring of chemicals to avoid bacterial regrowth. For UV-A/TiO(2)/H(2)O(2) process, the addition of H(2)O(2) improved Escherichia coli inactivation since the cell wall weakening, due to OH attacks, allowed H(2)O(2) to diffuse into the bacteria. However, a total elimination of the pharmaceuticals was not achieved during the inactivation process.

  5. Energy Effectiveness of Direct UV and UV/H2O2 Treatment of Estrogenic Chemicals in Biologically Treated Sewage

    Directory of Open Access Journals (Sweden)

    Kamilla M. S. Hansen

    2012-01-01

    Full Text Available Continuous exposure of aquatic life to estrogenic chemicals via wastewater treatment plant effluents has in recent years received considerable attention due to the high sensitivity of oviparous animals to disturbances of estrogen-controlled physiology. The removal efficiency by direct UV and the UV/H2O2 treatment was investigated in biologically treated sewage for most of the estrogenic compounds reported in wastewater. The investigated compounds included parabens, industrial phenols, sunscreen chemicals, and steroid estrogens. Treatment experiments were performed in a flow through setup. The effect of different concentrations of H2O2 and different UV doses was investigated for all compounds in an effluent from a biological wastewater treatment plant. Removal effectiveness increased with H2O2 concentration until 60 mg/L. The treatment effectiveness was reported as the electrical energy consumed per unit volume of water treated required for 90% removal of the investigated compound. It was found that the removal of all the compounds was dependent on the UV dose for both treatment methods. The required energy for 90% removal of the compounds was between 28 kWh/m3 (butylparaben and 1.2 kWh/m3 (estrone for the UV treatment. In comparison, the UV/H2O2 treatment required between 8.7 kWh/m3 for bisphenol A and benzophenone-7 and 1.8 kWh/m3 for ethinylestradiol.

  6. AOX removal from industrial wastewaters using advanced oxidation processes: assessment of a combined chemical-biological oxidation.

    Science.gov (United States)

    Luyten, J; Sniegowski, K; Van Eyck, K; Maertens, D; Timmermans, S; Liers, Sven; Braeken, L

    2013-01-01

    In this paper, the abatement of adsorbable halogenated organic compounds (AOX) from an industrial wastewater containing relatively high chloride concentrations by a combined chemical and biological oxidation is assessed. For chemical oxidation, the O(3)/UV, H(2)O(2)/UV and photo-Fenton processes are evaluated on pilot scale. Biological oxidation is simulated in a 4 h respirometry experiment with periodic aeration. The results show that a selective degradation of AOX with respect to the matrix compounds (expressed as chemical oxygen demand) could be achieved. For O(3)/UV, lowering the ratio of O(3) dosage to UV intensity leads to a better selectivity for AOX. During O(3)-based experiments, the AOX removal is generally less than during the H(2)O(2)-based experiments. However, after biological oxidation, the AOX levels are comparable. For H(2)O(2)/UV, optimal operating parameters for UV and H(2)O(2) dosage are next determined in a second run with another wastewater sample.

  7. UV-Enhanced NaClO Oxidation of Nitric Oxide from Simulated Flue Gas

    Directory of Open Access Journals (Sweden)

    Shao-long Yang

    2016-01-01

    Full Text Available A wet de-NOx technique based on an UV-enhanced NaClO oxidation process was investigated for simulated flue gas of a diesel engine using a bench-scale reaction chamber. The effects of UV irradiation time, initial pH value, and available chlorine concentration of NaClO solution were studied, respectively. The results showed that when the UV irradiation time was 17.5 min and the initial pH value of NaClO solution was 6, NO removal efficiency of UV/NaClO solution was increased by 19.6% compared with that of NaClO solution. Meanwhile, when the available chlorine concentration of NaClO solution decreased from 0.1 wt% to 0.05 wt%, the enhancement in NO removal efficiency of UV/NaClO solution increased from 19.6% to 24%, compared with that of NaClO solution. The reaction pathways of NaClO solution photolysis and NO removal by UV/NaClO process were preliminarily discussed. The results suggested that HOCl might be the most active species that released many UV-induced photooxidants through photolysis reactions, which played an important role in NO removal process.

  8. A solar-driven UV/Chlorine advanced oxidation process.

    Science.gov (United States)

    Chan, Po Yee; Gamal El-Din, Mohamed; Bolton, James R

    2012-11-01

    An overlap of the absorption spectrum of the hypochlorite ion (OCl(-)) and the ultraviolet (UV) end of the solar emission spectrum implies that solar photons can probably initiate the UV/chlorine advanced oxidation process (AOP). The application of this solar process to water and wastewater treatment has been investigated in this study. At the bench-scale, the OCl(-) photolysis quantum yield at 303 nm (representative of the lower end of the solar UV region) and at concentrations from 0 to 4.23 mM was 0.87 ± 0.01. Also the hydroxyl radical yield factor (for an OCl(-) concentration of 1.13 mM) was 0.70 ± 0.02. Application of this process, at the bench-scale and under actual sunlight, led to methylene blue (MB) photobleaching and cyclohexanoic acid (CHA) photodegradation. For MB photobleaching, the OCl(-) concentration was the key factor causing an increase in the pseudo first-order rate constants. The MB photobleaching quantum yield was affected by the MB concentration, but not much by the OCl(-) concentration. For CHA photodegradation, an optimal OCl(-) concentration of 1.55 mM was obtained for a 0.23 mM CHA concentration, and a scavenger effect was observed when higher OCl(-) concentrations were applied. Quantum yields of 0.09 ± 0.01 and 0.89 ± 0.06 were found for CHA photodegradation and OCl(-) photolysis, respectively. In addition, based on the Air Mass 1.5 reference solar spectrum and experimental quantum yields, a theoretical calculation method was developed to estimate the initial rate for photoreactions under sunlight. The theoretical initial rates agreed well with the experimental rates for both MB photobleaching and CHA photodegradation.

  9. Tuning the underwater oleophobicity of graphene oxide coatings via UV irradiation.

    Science.gov (United States)

    Li, Hang; Huang, Yi; Mao, Yating; Xu, Weiwei L; Ploehn, Harry J; Yu, Miao

    2014-09-07

    Ultraviolet (UV) irradiation was utilized to gradually modify the chemistry and structure of graphene oxide (GO) flakes, as confirmed by XPS and AFM. Ultrathin GO coatings/membranes, made of UV-irradiated flakes, showed tunable underwater oleophobicity. UV-treated, superoleophobic GO membranes exhibited excellent antifouling capability for oil/water separation.

  10. Simulation and comparative study on the oxidation kinetics of atrazine by UV/H₂O₂, UV/HSO₅⁻ and UV/S₂O₈²⁻.

    Science.gov (United States)

    Luo, Congwei; Ma, Jun; Jiang, Jin; Liu, Yongze; Song, Yang; Yang, Yi; Guan, Yinghong; Wu, Daoji

    2015-09-01

    This study comparatively investigated atrazine (ATZ) degradation by irradiation at the wavelength of 254 nm in the presence of peroxides including hydrogen peroxide (H2O2), peroxymonosulfate (HSO5(-)), and persulfate (S2O8(2-)) at various initial ATZ concentrations and oxidant dosages. The effects of water matrix, such as carbonate/bicarbonate (HCO3(-)/CO3(2-)), chloride ions (Cl(-)), and natural organic matter (NOM), were evaluated on these three advanced oxidation processes. A simple steady-state kinetic model was developed based on the initial rates of ATZ destruction, which could well describe the apparent pseudo-first-order rate constants (k(app), s(-1)) of ATZ degradation in these three processes. The specific roles of reactive species (i.e., HO·, SO4(-·), CO3(-·), and Cl2(-·)) under various experimental conditions were quantitatively evaluated based on their steady-state concentrations obtained from this model. Modeling results showed that the steady-state concentrations of HO· and SO4(-·) decreased with the increase of CO3(2-)/HCO3(-) concentration, and the relative contribution of HO· to ATZ degradation significantly decreased in UV/H2O2 and UV/HSO5(-) systems. On the other hand, the scavenging effect of HCO3(-)/CO3(2-) on the relative contribution of SO4(-·) to ATZ degradation was lower than that on HO·. The presence of Cl(-) (0.5-10 mM) significantly scavenged SO4(-·) but had slightly scavenging effect on HO· at the present experimental pH, resulting in greater decrease of k(app) in the UV/S2O8(2-) than UV/H2O2 and UV/HSO5(-) systems. Higher levels of Cl2(-·) were generated in the UV/S2O8(2-) than those in the UV/H2O2 and UV/HSO5(-) systems at the same Cl(-) concentrations. NOM significantly decreased k(app) due to its effects of competitive UV absorption and radical scavenging with the latter one being dominant. These results improve the understanding of the effects of water constituents for ATZ degradation in the UV-based oxidation

  11. Antiradiation UV Vaccine: UV Radiation, Biological effects, lesions and medical management - immune-therapy and immune-protection.

    Science.gov (United States)

    Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

    rabbits, 11-12 months old, live weight 3.5-3.7 (n=11), Balb mice, 2-3 months old, live weight 20-22 g (n=33), Wistar rats, 3-4 months old, live weight 180-220 g(n=33). The studies were approved by the Animal Care and Use Committee for ethical animal research equivalent, at each institution. Seven rabbits, ten mice, eleven Wistar rats were vaccinated with a UV antiradiation vaccine. A second group of animals was used as biological control which received vaccine but no UV Radiation and a third group of animals was used as control without any interventions. Before and after UV Radiation, Vaccination with the UV antiradiation vaccine were provided 17 days prior to UV exposure. The animals were irradiated by a DRT-1 UV generator lamp. The dose of irradiation for laboratory, experimental animals was 10-12 * Standard Erythema Dose (SED) at L=283,7 Laboratory animals were placed in to the box with ventilation. Results: Ultraviolet irradiation of the skin was performed with high doses and causes an inflammation or erythema in all experimental animals. However the grade of skin damage and inflammation was significantly different between animals protected by vaccination and non-protected, non-vaccinated animals. Animals UV-irradiated, but who did not receive the antiradiation vaccine suffered from extensive UV skin burns of second or third degree (grade 2-3). However, animals protected with the UV antiradiation vaccine demonstrated much mild forms of skin cellular injury - mainly erythema, first degree skin burns and a few small patches with second degree skin burns (grade 1-2). Discussion: The severity of skin damage depended on area of exposed skin, time and dose of UV irradiation. Skin injury could be divided into 4 major grades: 1. Faint erythema with dry desquamation. 2. Moderate to severe erythema. 3. Severe erythema with blistering, moist desquamation. 4. Toxic epidermal necrolysis. Mild doses of UV radiation and ionizing radiation can induce cell death by apoptosis and

  12. Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

    Directory of Open Access Journals (Sweden)

    Jeanette Beber de Souza

    2015-01-01

    Full Text Available The individual methods of disinfection peracetic acid (PAA and UV radiation and combined process PAA/UV in water (synthetic and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater, and coliphages (such as virus indicators. Under the experimental conditions investigated, doses of 2, 3, and 4 mg/L of PAA and contact time of 10 minutes and 60 and 90 s exposure to UV radiation, the results indicated that the combined method PAA/UV provided superior efficacy when compared to individual methods of disinfection.

  13. Effect of heat treatment in aluminium oxide preparation by UV/ozone oxidation for organic thin-film transistors.

    Science.gov (United States)

    Chinnam, Krishna Chytanya; Gleskova, Helena

    2013-07-01

    Effect of heat treatment in aluminium oxide (AlO(x)) preparation employing UV/ozone exposure of thermally-evaporated aluminium is reported. AlO(x) is combined with 1-octylphosphonic acid to form a gate dielectric in low-voltage organic thin-film transistors based on pentacene. For short UV/ozone exposure times the 100 degrees C-heating step that immediately follows UV/ozone oxidation of aluminium leads to a decrease in the transistor threshold voltage of up to 8% and - fourfold reduction in the gate dielectric current density. Transistors with AlO(x) prepared by 60-minute UV/ozone oxidation do not exhibit such behaviour. These results are explained in terms of reduced density of charged oxygen vacancies in the UV/ozone oxidized AlO(x).

  14. Increased formation of halomethanes during chlorination of chloramphenicol in drinking water by UV irradiation, persulfate oxidation, and combined UV/persulfate pre-treatments.

    Science.gov (United States)

    Wenhai, Chu; Tengfei, Chu; Erdeng, Du; Deng, Yang; Yingqing, Guo; Naiyun, Gao

    2016-02-01

    Ultraviolet/persulfate (UV/PS) has been widely used to generate sulfate radicals for degradation of water organic pollutants in previous studies. However, its impacts on disinfection byproduct formation during post-chlorination of degraded compounds is unclear. The objective of this study was to evaluate the impacts of UV irradiation, PS oxidation, and the combined UV/PS advanced oxidation process (AOP) pre-treatments on halomethane formation during the following chlorination of chloramphenicol (CAP), a model antibiotic commonly found in wastewater-impacted water. Results showed that CAP could be transformed to more trichloromethane (TCM) than monochloromethane (MCM) and dichloromethane (DCM) in the presence of excess chlorine. UV photolysis, PS oxidation and UV/PS AOP all directly decomposed CAP to produce halomethanes (HMs) before post-chlorination. Moreover, UV and UV/PS pre-treatments both enhanced the formation of all the HMs in the subsequent chlorination. PS pre-oxidation decreased the TCM formation during post-chlorination, but increased the yields of MCM, DCM and total HMs. UV pre-irradiation significantly increased the bromide utilization of HMs, whereas UV/PS pre-oxidation decreased the bromine incorporation and utilization of HMs from the chlorination of CAP in a low-bromide water. UV irradiation, PS oxidation, and UV/PS AOP can inactivate pathogens and degrade organic pollutants, but this benefit should be weighed against a potential risk of the increased halomethane formation from degraded organic pollutants with and without post-chlorination.

  15. Biological Superoxide In Manganese Oxide Formation

    Science.gov (United States)

    Hansel, C.; Learman, D.; Zeiner, C.; Santelli, C. M.

    2011-12-01

    Manganese (Mn) oxides are among the strongest sorbents and oxidants within the environment, controlling the fate and transport of numerous elements and the degradation of recalcitrant carbon. Both bacteria and fungi mediate the oxidation of Mn(II) to Mn(III/IV) oxides but the genetic and biochemical mechanisms responsible remain poorly understood. Furthermore, the physiological basis for microbial Mn(II) oxidation remains an enigma. We have recently reported that a common marine bacterium (Roseobacter sp. AzwK-3b) oxidizes Mn(II) via reaction with extracellular superoxide (O2-) produced during exponential growth. Here we expand this superoxide-mediated Mn(II) oxidation pathway to fungi, introducing a surprising homology between prokaryotic and eukaryotic metal redox processes. For instance, Stibella aciculosa, a common soil Ascomycete filamentous fungus, precipitates Mn oxides at the base of asexual reproductive structures (synnemata) used to support conidia (Figure 1). This distribution is a consequence of localized production of superoxide (and it's dismutation product hydrogen peroxide, H2O2), leading to abiotic oxidation of Mn(II) by superoxide. Disruption of NADPH oxidase activity using the oxidoreductase inhibitor DPI leads to diminished cell differentiation and subsequent Mn(II) oxidation inhibition. Addition of Cu(II) (an effective superoxide scavenger) leads to a concentration dependent decrease in Mn oxide formation. We predict that due to the widespread production of extracellular superoxide within the fungal and likely bacterial kingdoms, biological superoxide may be an important contributor to the cycling of Mn, as well as other metals (e.g., Hg, Fe). Current and future explorations of the genes and proteins involved in superoxide production and Mn(II) oxidation will ideally lend insight into the physiological and biochemical basis for these processes.

  16. Deep-UV solid state light sources in the tactical biological sensor

    Science.gov (United States)

    Cabalo, Jerry; De Lucia, Marla; Narayanan, Fiona; Poldmae, Aime; Sickenberger, David

    2006-05-01

    A number of strategies to meet the need for a small and inexpensive biosensor that mitigates military and civilian vulnerabilities to biological weapons are currently being pursued. Among them is UV induced biological fluorescence. UV induced biofluorescence is a potentially successful strategy because it involves no chemical consumables and it is an "on-line" detection method where particles can be interrogated without impaction onto a substrate or into a liquid. Indeed, there are already existing fluorescence based sensors already in place, yet these are limited by the cost and power consumption of the laser based UV excitation sources. Fortunately, inexpensive and low power solid state UV sources arising from the Defense Advanced Research Projects Agency's (DARPA) Semiconductor UV Optical Sources (SUVOS) project have become commercially available in wavelengths capable of exciting aromatic amino acids (e.g. tryptophan) and metabolic products (e.g. NADH). The TAC-Bio Sensor is capable of exploiting either source wavelength and will ultimately include both source wavelengths within a single sensor. Initial work with the deep UV sources involves the correct optical filtering for the devices. The primary emission from both the 280 nm and 340 nm devices occurs at the design wavelength and is about 20 nm FWHM, however, there is a tail extending to the longer wavelengths that interferes with the fluorescence signal. A system of optical filters that sufficiently removes the long wavelength component from the UV source is designed and tested for the deep UV sources. Ongoing work with the sensor has confirmed that sensitivity to small biological particles is enhanced with the deeper wavelengths. When the 340 nm sources are placed in the TAC-Bio, it is capable of detecting 4 micron diameter Bacillus globigii (BG, Dugway, washed 4X) spore agglomerates. The deep UV sources show an improvement in signal to noise of 2, permitting the detection of 3 micron diameter BG

  17. Novel photocatalysis oxidation system UV/Fe2+/air to degrade 4-CP wastewater

    Institute of Scientific and Technical Information of China (English)

    DU Yingxun; ZHOU Minghua; LEI Lecheng

    2005-01-01

    This paper reported the degradation of 4-CP wastewater by a novel photocatalysis oxidation system--UV/Fe2+/air system, in which air was used as a cheap oxidant that reacted with the excitation state of organics to form H2O2 under the UV light. The formed H2O2 reacted with the added ferrous ion to form Fenton reaction and led to the quick degradation of organic pollutants. It was found that 4-CP could be completely removed within 40 min. The degradation of 4-CP in the UV/Fe2+/air system was superior to the conventional UV/Fenton system (the initial concentration of H2O2 was 22 mg-L-1). UV/Fe2+/air is an effective and cheap method for treatment of the organics that can be excited by UV light.

  18. Involvement of inositol biosynthesis and nitric oxide in the mediation of UV-B induced oxidative stress

    Directory of Open Access Journals (Sweden)

    Dmytro I Lytvyn

    2016-04-01

    Full Text Available The involvement of NO-signaling in ultraviolet B (UV-B induced oxidative stress in plants is an open question. Inositol biosynthesis contributes to numerous cellular functions, including the regulation of plants tolerance to stress. This work reveals the involvement of inositol-3-phosphate synthase 1 (IPS1, a key enzyme for biosynthesis of myo-inositol and its derivatives, in the response to NO-dependent oxidative stress in Arabidopsis. Homozygous mutants deficient for IPS1 (atips1 and wild-type plants were transformed with a reduction-oxidation-sensitive green fluorescent protein 2 (grx1-rogfp2 and used for the dynamic measurement of UV-B-induced and SNP (sodium nitroprusside-mediated oxidative stresses by confocal microscopy. atips1 mutants displayed greater tissue-specific resistance to the action of UV-B than the wild type. SNP can act both as an oxidant or repairer depending on the applied concentration, but mutant plants were more tolerant than the wild type to nitrosative effects of high concentration of SNP. Additionally, pretreatment with low concentrations of SNP (10, 100 μM before UV-B irradiation resulted in a tissue-specific protective effect that was enhanced in atips1. We conclude that the interplay between nitric oxide and inositol signaling can be involved in the mediation of UV-B-initiated oxidative stress in the plant cell.

  19. Environmental and biological factors influencing the UV-C resistance of Listeria monocytogenes.

    Science.gov (United States)

    Gayán, E; Serrano, M J; Pagán, R; Álvarez, I; Condón, S

    2015-04-01

    In this investigation, the effect of microbiological factors (strain, growth phase, exposition to sublethal stresses, and photorepair ability), treatment medium characteristics (pH, water activity, and absorption coefficient), and processing parameters (dose and temperature) on the UV resistance of Listeria monocytogenes was studied. The dose to inactivate 99.99% of the initial population of the five strains tested ranged from 21.84 J/mL (STCC 5672) to 14.66 J/mL (STCC 4031). The UV inactivation of the most resistant strain did not change in different growth phases and after exposure to sublethal heat, acid, basic, and oxidative shocks. The pH and water activity of the treatment medium did not affect the UV resistance of L. monocytogenes, whereas the inactivation rate decreased exponentially with the absorption coefficient. The lethal effect of UV radiation increased synergistically with temperature between 50 and 60 °C (UV-H treatment). A UV-H treatment of 27.10 J/mL at 55 °C reached 2.99 and 3.69 Log10 inactivation cycles of L. monocytogenes in orange juice and vegetable broth, and more than 5 Log10 cycles in apple juice and chicken broth. This synergistic effect opens the possibility to design UV combined processes for the pasteurization of liquid foods with high absorptivity.

  20. UV-Shielding and Catalytic Characteristics of Nanoscale Zinc-Cerium Oxides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fine particles of zinc-cerium oxides (ZCO) used as an ultraviolet filter were prepared via combustion synthesis route. The catalytic activity, UV-shielding performance, surface modification and application of ZCO in polyester varnish were discussed in detail. The experimental results indicate that the photo-catalytic activity of ZCO is much smaller than these of ZnO and TiO2; the oxidation catalytic activity of ZCO is far lower than that of CeO2; the ZCO has shown excellent ultraviolet absorption in the range of UV;addition modified ZCO (MZCO) into polyester will enhance the UV-shielding capability of polyester.

  1. Disinfection and oxidation of sewage effluent water using ozone and UV technologies.

    Science.gov (United States)

    Oh, B S; Park, S J; Jung, Y J; Park, S Y; Kang, J W

    2007-01-01

    This study was aimed at exploring the reclamation of sewage treatment plant effluent water (SEW) as an alternative water resource. For the oxidation of SEW, an ozone-UV system, based on the results of the combined ozone/UV process performed in our previous study, was set up under practical conditions, including a series type, continuous mode, semi-pilot scale operation (1.5 m3/d). As a result, the serial contact of the ozone and UV reactors showed lower CODCr and TOC removal efficiencies. However, these were greatly enhanced by recycling the water flow of the ozone-UV system at 40Q, as a result of the improvements in the transferred ozone dose in the ozone reactor and the contact efficiency between photons and ozone in the UV reactor, which approached that achieved in the combined ozone/UV process. For the disinfection of SEW, carried out in a syringe-type batch reactor, the increase of instantaneous ozone demand (ozone ID) led to a higher inactivation efficiency, an increased UV transmittance due to ozonation, and an enhanced inactivation rate of E. coli in the UV reactor. Additionally, it was concluded that the ozone/UV process could overcome the limitations of the ozone alone and UV alone processes for the reclamation of sewage effluent water.

  2. INVESTIGATION OF HYBRID OXIDATION PROCESSES (UV/TIO2/H2O2) FOR SELECTED ORGANIC MICROPOLLUTANTS ELIMINATION AND CHANGE OF WATER TOXICITY

    OpenAIRE

    2016-01-01

    All of the available and applicable chemical oxidants were found to affect the quality of the treated water or wastewater. It has been commonly observed that the oxidation processes generate by-products, which often possess unknown biological activity. Accordingly, the present study assessed the degree of degradation of mixture of selected micropollutants and the change of the solution toxicity in the UV/TiO2/H2O2 hybrid process. Water containing bisphenol A and diclofenac at a concentration ...

  3. Cholesterol oxidation products and their biological importance

    DEFF Research Database (Denmark)

    Kulig, Waldemar; Cwiklik, Lukasz; Jurkiewicz, Piotr

    2016-01-01

    The main biological cause of oxysterols is the oxidation of cholesterol. They differ from cholesterol by the presence of additional polar groups that are typically hydroxyl, keto, hydroperoxy, epoxy, or carboxyl moieties. Under typical conditions, oxysterol concentration is maintained at a very low...... and precisely regulated level, with an excess of cholesterol. Like cholesterol, many oxysterols are hydrophobic and hence confined to cell membranes. However, small chemical differences between the sterols can significantly affect how they interact with other membrane components, and this in turn can have...

  4. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kääriäinen, Tommi, E-mail: tommi.kaariainen@colorado.edu [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Johansson, Petri, E-mail: petri.johansson@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Kotkamo, Sami, E-mail: sami.kotkamo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Seppänen, Tarja, E-mail: tarja.seppanen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Cameron, David C., E-mail: david.cameron@miktech.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland)

    2014-11-03

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved.

  5. Roles of manganese oxides in degradation of phenol under UV-Vis irradiation: adsorption, oxidation, and photocatalysis.

    Science.gov (United States)

    Zhang, Qin; Cheng, Xiaodi; Zheng, Chen; Feng, Xionghan; Qiu, Guohong; Tan, Wenfeng; Liu, Fan

    2011-01-01

    Manganese oxides are known as one type of semiconductors, but their photocatalysis characteristics have not been deeply explored. In this study, photocatalytic degradation of phenol using several synthesized manganese oxides, i.e, acidic birnessite (BIR-H), alkaline birnessite (BIR-OH), cryptomelane (CRY) and todorokite (TOD), were comparatively investigated. To elucidate phenol degradation mechanisms, X-ray diffraction (XRD), ICP-AES (inductively coupled plasma-atomic emission spectroscopy), TEM (transmission electronic microscope), N2 physisorption at 77 K and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed to characterize the structural, compositional, morphological, specific surface area and optical absorption properties of the manganese oxides. After 12 hr of UV-Vis irradiation, the total organic carbon (TOC) removal rate reached 62.1%, 43.1%, 25.4%, and 22.5% for cryptomelane, acidic birnessite, todorokite and alkaline birnessite, respectively. Compared to the reactions in the dark condition, UV-Vis exposure improved the TOC removal rates by 55.8%, 31.9%, 23.4% and 17.9%. This suggests a weak ability of manganese oxides to degrade phenol in the dark condition, while UV-Vis light irradiation could significantly enhance phenol degradation. The manganese minerals exhibited photocatalytic activities in the order of: CRY > BIR-H > TOD > BIR-OH. There may be three possible mechanisms for photochemical degradation: (1) direct photolysis of phenol; (2) direct oxidation of phenol by manganese oxides; (3) photocatalytic oxidation of phenol by manganese oxides. Photocatalytic oxidation of phenol appeared to be the dominant mechanism.

  6. Removal of disinfection by-product precursors with ozone-UV advanced oxidation process.

    Science.gov (United States)

    Chin, A; Bérubé, P R

    2005-05-01

    The efficacy of using ozone (O3), ultraviolet irradiation (UV) and the combined O3-UV advanced oxidation process (AOP) to remove 2 classes of disinfection by-product (DBP) precursors from raw surface water samples have been evaluated and compared. In particular, trihalomethane and haloacetic acids formation potentials were measured. Laboratory batch scale experiments were carried out as a function of ozone and UV dosage in order to study the removal kinetics. It is concluded that the combined O3-UV AOP is more effective than either the ozone or UV treatment alone. Ozone-UV AOP is capable of mineralizing up to 50% of the total organic carbon from the raw source water at an ozone dose of 0.62+/-0.019 mg O3/mL and a UV dose of 1.61 W s/cm2. In addition, O3-UV AOP can reduce trihalomethane formation potential by roughly 80% and haloacetic acids formation potential by roughly 70% at the same ozone and UV dosage.

  7. Near UV-Blue Excitable Green-Emitting Nanocrystalline Oxide

    Directory of Open Access Journals (Sweden)

    C. E. Rodríguez-García

    2011-01-01

    Full Text Available Green-emitting Eu-activated powders were produced by a two-stage method consisting of pressure-assisted combustion synthesis and postannealing in ammonia. The as-synthesized powders exhibited a red photoluminescence (PL peak located at =616 nm when excited with =395 nm UV. This emission peak corresponds to the 5D0→7F2 transition in Eu3+. After annealing in ammonia, the PL emission changed to an intense broad-band peak centered at =500 nm, most likely produced by 4f65d1→4f7 electronic transitions in Eu2+. This green-emitting phosphor has excitation band in the near UV-blue region (=300–450 nm. X-ray diffraction analysis reveals mainly the orthorhombic EuAlO3 and Al2O3 phases. Transmission electron microscopy observations showed that the grains are formed by faceted nanocrystals (~4 nm of polygonal shape. The excellent excitation and emission properties make these powders very promising to be used as phosphors in UV solid-state diodes coupled to activate white-emitting lamps.

  8. Impact of hydrodynamics on pollutant degradation and energy efficiency of VUV/UV and H2O2/UV oxidation processes.

    Science.gov (United States)

    Bagheri, Mehdi; Mohseni, Madjid

    2015-12-01

    The Vacuum-UV/UV process, an incipient catalyst/chemical-free advanced oxidation process (AOP), is potentially a cost-effective solution for the removal of harmful micropollutants from water. Utilizing a novel mechanistic numerical model, this work aimed to establish a thorough understanding of the degradation mechanisms in the VUV/UV process operating under continuous flow conditions, when compared with the widely applied H2O2/UV AOP. Of particular interest was the examination of the impact of flow characteristics (hydrodynamics) on the degradation efficacy of a target micropollutant during the VUV/UV and H2O2/UV AOPs. While hydroxyl radical (OH) oxidation was the dominant degradation pathway in both processes, the degradation efficacy of the VUV/UV process showed much stronger correlation with the extent of mixing in the photoreactor. Under a uniform flow regime, the degradation efficiency of the target pollutant achieved by the H2O2/UV process with 2- and 5 ppm H2O2 was greater than that provided by the VUV/UV process. Nonetheless, introduction of mixing and circulation zones to the VUV/UV reactor resulted in superior performance compared with the H2O2/UV AOP. Based on the electrical energy-per-order (EEO) analysis, incorporation of circulation zones resulted in a reduction of up to 50% in the overall energy cost of the VUV/UV AOP, while the corresponding reduction for the 5-ppm H2O2/UV system was less than 5%. Furthermore, the extent of OH scavenging of natural organic matter (NOM) on energy efficiency of the VUV/UV and H2O2/UV AOPs under continuous flow conditions was assessed using the EEO analysis.

  9. Vitamin C affects the antioxidative/oxidative status in rats irradiated with ultraviolet (UV) and infrared (IR) light

    DEFF Research Database (Denmark)

    Niemiec, T.; Sawosz, E.; Chwalibog, André

    2006-01-01

    /oxidative status. UV and IR radiation promoted oxidative DNA degradation in rat livers and supplementation with ascorbic acid strengthened the prooxidative effects on DNA oxidation in rats irradiated with UV or IR light. Vitamin C also increased the tiobarbituric acid reactive substances (TBARS) concentration...

  10. A combination of He-Ne laser irradiation and exogenous NO application efficiently protect wheat seedling from oxidative stress caused by elevated UV-B stress.

    Science.gov (United States)

    Li, Yongfeng; Gao, Limei; Han, Rong

    2016-12-01

    The elevated ultraviolet-B (UV-B) stress induces the accumulation of a variety of intracellular reactive oxygen species (ROS), which seems to cause oxidative stress for plants. To date, very little work has been done to evaluate the biological effects of a combined treatment with He-Ne laser irradiation and exogenous nitric oxide (NO) application on oxidative stress resulting from UV-B radiation. Thus, our study investigated the effects of a combination with He-Ne laser irradiation and exogenous NO treatment on oxidative damages in wheat seedlings under elevated UV-B stress. Our data showed that the reductions in ROS levels, membrane damage parameters, while the increments in antioxidant contents and antioxidant enzyme activity caused by a combination with He-Ne laser and exogenous NO treatment were greater than those of each individual treatment. Furthermore, these treatments had a similar effect on transcriptional activities of plant antioxidant enzymes. This implied that the protective effects of a combination with He-Ne laser irradiation and exogenous NO treatment on oxidative stress resulting from UV-B radiation was more efficient than each individual treatment with He-Ne laser or NO molecule. Our findings might provide beneficial theoretical references for identifying some effective new pathways for plant UV-B protection.

  11. Inactivation of Amphidinium sp. in ballast waters using UV/Ag-TiO2+O3 advanced oxidation treatment.

    Science.gov (United States)

    Wu, Donghai; You, Hong; Zhang, Ran; Chen, Chuan; Lee, Duu-Jong

    2011-11-01

    Ballast water poses a biological threat to the world's waterways by transferring aquatic species from one body of water to another. This study investigates the use of combined ultraviolet (UV)/Ag-TiO(2)+ozone (O(3)) processes for treating ballast water using Amphidinium sp. as an indicator microorganism. Sufficient Amphidinium sp. cells in ballast waters can be inactivated using O(3) alone, UV irradiation alone (with or without an Ag-TiO(2) coating), and combined treatments. For the low inactivation ratio (treatment produced excess hydroxyl radicals and total residual oxidants (TROs), and readily damaged cell membranes to release intracellular substances. The comparison tests revealed that the combined treatments synergistically inactivate Escherichia coli in ballast waters. However, the combined process did not synergistically inactivate Amphidinium sp. cells. Inactivating different aqua species in ballast waters needs distinct treatment methods and dosages.

  12. UV-H2O2 based AOP and its integration with biological activated carbon treatment for DBP reduction in drinking water.

    Science.gov (United States)

    Toor, Ramn; Mohseni, Madjid

    2007-02-01

    The presence of disinfection byproducts (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs) in drinking water is of great concern due to their adverse effects on human health. Emerging regulation limiting the concentration of DBPs in drinking water has increased demands for technologies and processes which reduce the formation of DBPs in drinking water. In this study, UV-H2O2 based advance oxidation process (AOP) was used to treat raw surface water. Experiments were conducted using low pressure mercury vapor UV lamps in collimated beam and flow-through annular photoreactors. The effect of UV fluence (0-3500 mJ cm(-2)) and hydrogen peroxide concentration (0-23 mg l(-1)) in reducing the concentration of THMs and HAAs was examined. The UV-H2O2 AOP was then coupled with a downstream biological activated carbon (BAC) treatment to assess the synergetic benefits of combining the two treatments. It was observed that UV-H2O2 AOP was only effective at reducing DBPs at UV fluences of more than 1000 mJ cm(-2) and initial H2O2 concentrations of about or greater than 23 mg l(-1). However, the combined AOP-BAC treatment showed significant reductions of 43%, 52%, and 59% relative to untreated raw water for DBPs, TOC, and UV254, respectively.

  13. Inactivation of adenovirus using low-dose UV/H2O2 advanced oxidation.

    Science.gov (United States)

    Bounty, Sarah; Rodriguez, Roberto A; Linden, Karl G

    2012-12-01

    Adenovirus has consistently been observed to be the most resistant known pathogen to disinfection by ultraviolet light. This has had an impact on regulations set by the United States Environmental Protection Agency regarding the use of UV disinfection for virus inactivation in groundwater and surface water. In this study, enhancement of UV inactivation of adenovirus was evaluated when hydrogen peroxide was added to create an advanced oxidation process (AOP). While 4 log reduction of adenovirus was determined to require a UV dose (UV fluence) of about 200 mJ/cm(2) from a low pressure (LP) UV source (emitting at 253.7 nm), addition of 10 mg/L H(2)O(2) achieved 4 log inactivation at a dose of 120 mJ/cm(2). DNA damage was assessed using a novel nested PCR approach, and similar levels of DNA damage between the two different treatments were noted, suggesting the AOP enhancement in inactivation was not due to additional DNA damage. Hydroxyl radicals produced in the advanced oxidation process are likely able to damage parts of the virus not targeted by LPUV, such as attachment proteins, enhancing the UV-induced inactivation. The AOP-enhanced inactivation potential was modeled in three natural waters. This research sheds light on the inactivation mechanisms of viruses with ultraviolet light and in the presence of hydroxyl radicals and provides a practical means to enhance inactivation of this UV-resistant virus.

  14. A solid oxide photoelectrochemical cell with UV light-driven oxygen storage in mixed conducting electrodes

    Science.gov (United States)

    Walch, Gregor; Rotter, Bernhard; Brunauer, Georg Christoph; Esmaeili, Esmaeil; Opitz, Alexander Karl; Kubicek, Markus; Summhammer, Johann; Ponweiser, Karl

    2017-01-01

    A single crystalline SrTiO3 working electrode in a zirconia-based solid oxide electrochemical cell is illuminated by UV light at temperatures of 360–460 °C. In addition to photovoltaic effects, this leads to the build-up of a battery-type voltage up to more than 300 mV. After switching off UV light, this voltage only slowly decays. It is caused by UV-induced oxygen incorporation into the mixed conducting working electrode and thus by changes of the oxygen stoichiometry δ in SrTiO3–δ under UV illumination. These changes of the oxygen content could be followed in time-dependent voltage measurements and also manifest themselves in time-dependent resistance changes during and after UV illumination. Discharge currents measured after UV illumination reveal that a large fraction of the existing oxygen vacancies in SrTiO3 become filled under UV light. Additional measurements on cells with TiO2 thin film electrodes show the broader applicability of this novel approach for transforming light into chemical energy and thus the feasibility of solid oxide photoelectrochemical cells (SOPECs) in general and of a “light-charged oxygen battery” in particular. PMID:28261480

  15. Degradation and mineralization of Bisphenol A (BPA) in aqueous solution using advanced oxidation processes: UV/H2O2 and UV/S2O8(2-) oxidation systems.

    Science.gov (United States)

    Sharma, Jyoti; Mishra, I M; Kumar, Vineet

    2015-06-01

    This work reports on the removal and mineralization of an endocrine disrupting chemical, Bisphenol A (BPA) at a concentration of 0.22 mM in aqueous solution using inorganic oxidants (hydrogen peroxide, H2O2 and sodium persulfate, Na2S2O8;S2O8(2-)) under UV irradiation at a wavelength of 254 nm and 40 W power (Io = 1.26 × 10(-6) E s(-1)) at its natural pH and a temperature of 29 ± 3 °C. With an optimum persulfate concentration of 1.26 mM, the UV/S2O8(2-) process resulted in ∼95% BPA removal after 240 min of irradiation. The optimum BPA removal was found to be ∼85% with a H2O2 concentration of 11.76 mM. At higher concentrations, either of the oxidants showed an adverse effect because of the quenching of the hydroxyl or sulfate radicals in the BPA solution. The sulfate-based oxidation process could be used over a wider initial pH range of 3-12, but the hydroxyl radical-based oxidation of BPA should be carried out in the acidic pH range only. The water matrix components (bicarbonate, chloride and humic acid) showed higher scavenging effect in hydroxyl radical-based oxidation than that in the sulfate radical-based oxidation of BPA. UV/S2O8(2-) oxidation system utilized less energy (307 kWh/m(3)) EE/O in comparison to UV/H2O2 system (509 kWh/m(3)) under optimum operating conditions. The cost of UV irradiation far outweighed the cost of the oxidants in the process. However, the total cost of treatment of persulfate-based system was much lower than that of H2O2-based oxidation system.

  16. UV-activated persulfate oxidation and regeneration of NOM-Saturated granular activated carbon.

    Science.gov (United States)

    An, Dong; Westerhoff, Paul; Zheng, Mengxin; Wu, Mengyuan; Yang, Yu; Chiu, Chao-An

    2015-04-15

    A new method of ultraviolet light (UV) activated persulfate (PS) oxidation was investigated to regenerate granular activated carbon (GAC) in drinking water applications. The improvements in iodine and methylene blue numbers measured in the GAC after ultraviolet- (UV) activated persulfate suggested that the GAC preloaded with natural organic matter (NOM) was chemically regenerated. An experimental matrix for UV-activated persulfate regeneration included a range of persulfate doses and different UV wavelengths. Over 87% of the initial iodine number for GAC was restored under the optimum conditions, perfulfate dosage 60 g/L and UV exposure 1.75 × 10(4) mJ/cm(2). The persulfate dosages had little effect on the recovery of the methylene blue number, which was approximately 65%. Persulfate activation at 185 nm was superior to activation at 254 nm. UV activation of persulfate in the presence of GAC produced acid, lowering the solution pH. Higher persulfate concentrations and UV exposure resulted in greater GAC regeneration. Typical organic and inorganic byproducts (e.g., benzene compounds and sulfate ions) were measured as a component of treated water quality safety. This study provides a proof-of-concept that can be used to optimize pilot-scale and full-scale UV-activated persulfate for regeneration of NOM-saturated GAC.

  17. Roles of manganese oxides in degradation of phenol under UV-Vis irradiation: Adsorption, oxidation, and photocatalysis

    Institute of Scientific and Technical Information of China (English)

    Qin Zhang; Xiaodi Cheng; Chen Zheng; Xionghan Feng; Guohong Qiu; Wenfeng Tan; Fan Liu

    2011-01-01

    Manganese oxides are known as one type of semiconductors,but their photocatalysis characteristics have not teen deeply explored.In this study,photocatalytic degradation of phenol using several synthesized manganese oxides,i.e,acidic birnessite (BIR-H),alkaline birnessite (BIR-OH),cryptomelane (CRY) and todorokite (TOD),were comparatively investigated.To elucidate phenol degradation mechanisms,X-ray diffraction (XRD),ICP-AES (inductively coupled plasma-atomic emission spectroscopy),TEM (transmission electronic microscope),N2 physisorption at 77 K and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed to characterize the structural,compositional,morphological,specific surface area and optical absorption properties of the manganese oxides.After 12 hr of UV-Vis irradiation,the total organic carbon (TOC) removal rate reached 62.1%,43.1%,25.4%,and 22.5% for cryptomelane,acidic birnessite,todorokite and alkaline birnessite,respectively.Compared to the reactions in the dark condition,UVVis exposure improved the TOC removal rates by 55.8%,31.9%,23.4% and 17.9%.This suggests a weak ability of manganese oxides to degrade phenol in the dark condition,while UV-Vis light irradiation could significantly enhance phenol degradation.The manganese minerals exhibited photocatalytic activities in the order of:CRY > BIR-H > TOD > BIR-OH.There may be three possible mechanisms for photochemical degradation:(1) direct photolysis of phenol; (2) direct oxidation of phenol by manganese oxides; (3) photocatalytic oxidation of phenol by manganese oxides.Photocatalytic oxidation of phenol appeared to be the dominant mechanism.

  18. Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms.

    Science.gov (United States)

    Paul, Nigel D; Moore, Jason P; McPherson, Martin; Lambourne, Cathryn; Croft, Patricia; Heaton, Joanna C; Wargent, Jason J

    2012-08-01

    Solar ultraviolet (UV)-B radiation (280-315 nm) has a wide range of effects on terrestrial ecosystems, yet our understanding of how UV-B influences the complex interactions of plants with pest, pathogen and related microorganisms remains limited. Here, we report the results of a series of experiments in Lactuca sativa which aimed to characterize not only key plant responses to UV radiation in a field environment but also consequential effects for plant interactions with a sap-feeding insect, two model plant pathogens and phylloplane microorganism populations. Three spectrally modifying filters with contrasting UV transmissions were used to filter ambient sunlight, and when compared with our UV-inclusive filter, L. sativa plants grown in a zero UV-B environment showed significantly increased shoot fresh weight, reduced foliar pigment concentrations and suppressed population growth of green peach aphid (Myzus persicae). Plants grown under a filter which allowed partial transmission of UV-A radiation and negligible UV-B transmission showed increased density of leaf surface phylloplane microbes compared with the UV-inclusive treatment. Effects of UV treatment on the severity of two plant pathogens, Bremia lactucae and Botrytis cinerea, were complex as both the UV-inclusive and zero UV-B filters reduced the severity of pathogen persistence. These results are discussed with reference to known spectral responses of plants, insects and microorganisms, and contrasted with established fundamental responses of plants and other organisms to solar UV radiation, with particular emphasis on the need for future integration between different experimental approaches when investigating the effects of solar UV radiation.

  19. Disinfection of Spacecraft Potable Water Systems by Photocatalytic Oxidation Using UV-A Light Emitting Diodes

    Science.gov (United States)

    Birmele, Michele N.; O'Neal, Jeremy A.; Roberts, Michael S.

    2011-01-01

    Ultraviolet (UV) light has long been used in terrestrial water treatment systems for photodisinfection and the removal of organic compounds by several processes including photoadsorption, photolysis, and photocatalytic oxidation/reduction. Despite its effectiveness for water treatment, UV has not been explored for spacecraft applications because of concerns about the safety and reliability of mercury-containing UV lamps. However, recent advances in ultraviolet light emitting diodes (UV LEDs) have enabled the utilization of nanomaterials that possess the appropriate optical properties for the manufacture of LEDs capable of producing monochromatic light at germicidal wavelengths. This report describes the testing of a commercial-off-the-shelf, high power Nichia UV-A LED (250mW A365nnJ for the excitation of titanium dioxide as a point-of-use (POD) disinfection device in a potable water system. The combination of an immobilized, high surface area photocatalyst with a UV-A LED is promising for potable water system disinfection since toxic chemicals and resupply requirements are reduced. No additional consumables like chemical biocides, absorption columns, or filters are required to disinfect and/or remove potentially toxic disinfectants from the potable water prior to use. Experiments were conducted in a static test stand consisting of a polypropylene microtiter plate containing 3mm glass balls coated with titanium dioxide. Wells filled with water were exposed to ultraviolet light from an actively-cooled UV-A LED positioned above each well and inoculated with six individual challenge microorganisms recovered from the International Space Station (ISS): Burkholderia cepacia, Cupriavidus metallidurans, Methylobacterium fujisawaense, Pseudomonas aeruginosa, Sphingomonas paucimobilis and Wautersia basilensis. Exposure to the Nichia UV-A LED with photocatalytic oxidation resulted in a complete (>7-log) reduction of each challenge bacteria population in <180 minutes of contact

  20. UV and electron-assisted oxidation of Al and Ru

    NARCIS (Netherlands)

    Ernst, M.A.

    2009-01-01

    To ensure a continuing miniaturization in the semiconductor industry, new technologies need to be developed to define ever smaller patterns on the silicon substrates. One of these emerging technologies is extreme ultraviolet (EUV) lithography. Unfortunately, EUV light causes oxidation of the optical

  1. Evaluation of O{sub 3}UV e H{sub 2}O{sub 2}/UV processes combined with biological activated carbon for reuse refinery waste water; Avaliacao dos processos O{sub 3}UV e H{sub 2}O{sub 2}/UV combinados com carvao ativado granulado com biofilme para reuso de efluentes de refinaria

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Bianca Miguel de; Dezotti, Marcia [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil); Cerqueira, Ana Claudia Figueiras Pereira de [Petroleo Brasileiro S.A. (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas e Desenvolvimento

    2012-07-01

    The treatment of refinery wastewater by advanced oxidation processes (AOP) coupled with biological activated carbon (BAC) was investigated aiming to generate water for reuse. The Gabriel Passos Refinery wastewater was previously treated in a membrane bioreactor, but still presented a high TOC content (30 mg/L) which may cause biofouling in the subsequent process of reverse osmosis. O3/UV and H2O2/UV processes were employed to oxidize the organic matter and BAC process to remove the residual organic matter from the AOP effluent. AOP promoted oxidation of recalcitrant organic matter as observed by drops on the treated wastewater absorbance and TOC values. BAC filters reached a TOC removal of 65% after 84 days of operation, while GAC filters were saturated after 28 days. Inoculated sand filters were also tested at different flow rates to compare with BAC filters. Low TOC values were achieved by the combined treatment, reaching values around 5 mg/L and allowing water reuse. BAC filters showed to be quite efficient for removal of organic compounds found in biologically treated oil refinery wastewater. (author)

  2. Oxidation of Sulfonamides in Aqueous Solution by UV-TiO2-Fe(VI).

    Science.gov (United States)

    Ma, Yan; Zhang, Kejia; Li, Cong; Zhang, Tuqiao; Gao, Naiyun

    2015-01-01

    The photocatalytic degradation of sulfonamides in aqueous TiO2 suspension under UV irradiation has been investigated using potassium ferrate as electron acceptors. The results showed that the stability of Fe(VI) is dependent on pH significantly, and the stability reduces obviously in the presence of UV-TiO2. The experiments indicated that Fe(VI) could effectively scavenge the conduction band electrons from the surface of TiO2. The photocatalytic oxidation of sulfonamides with Fe(VI) was found to be much faster than that without Fe(VI). The SD, SM, and SMX concentration was greatly reduced by 89.2%, 83.4%, and 82.0%, respectively, after 10 min with UV-TiO2-Fe(VI), comparing to 65.2%, 66.0%, and 71.9%, respectively, with Fe(VI) only in the dark and 71.3%, 72.7%, and 76.0%, respectively, with UV-TiO2. The pH value of solution significantly influenced the sulfonamides degradation in UV-TiO2-Fe(VI) system. The degradation amount of sulfonamides after 10 min was a maximum at pH 7. The intermediate products of sulfonamides oxidation by UV-TiO2-Fe(VI) were analysed by LC-HESI-MS-MS and the results suggested that a majority of sulfonamides turned into large-molecule products without complete mineralization.

  3. Oxidative degradation of N-Nitrosopyrrolidine by the ozone/UV process: Kinetics and pathways.

    Science.gov (United States)

    Chen, Zhi; Fang, Jingyun; Fan, Chihhao; Shang, Chii

    2016-05-01

    N-Nitrosopyrrolidine (NPYR) is an emerging contaminant in drinking water and wastewater. The degradation kinetics and mechanisms of NPYR degradation by the O3/UV process were investigated and compared with those of UV direct photolysis and ozonation. A synergistic effect of ozone and UV was observed in the degradation of NPYR due to the accelerated production of OH• by ozone photolysis. This effect was more pronounced at higher ozone dosages. The second-order rate constants of NPYR reacting with OH• and ozone was determined to be 1.38 (± 0.05) × 10(9) M(-1) s(-1) and 0.31 (± 0.02) M(-1) s(-1), respectively. The quantum yield by direct UV photolysis was 0.3 (± 0.01). An empirical model using Rct (the ratio of the exposure of OH• to that of ozone) was established for NPYR degradation in treated drinking water and showed that the contributions of direct UV photolysis and OH• oxidation on NPYR degradation were both significant. As the reaction proceeded, the contribution by OH• became less important due to the exhausting of ozone. Nitrate was the major product in the O3/UV process by two possible pathways. One is through the cleavage of nitroso group to form NO• followed by hydrolysis, and the other is the oxidation of the intermediates of amines by ozonation.

  4. Improving the photocatalytic activity of graphene oxide/ZnO nanorod films by UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rokhsat, Eliza [Department of Physics, Central Tehran Branch, I. A. University, Tehran (Iran, Islamic Republic of); Akhavan, Omid, E-mail: oakhavan@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2016-05-15

    Highlights: • ZnO nanorod-graphene oxide composite thin films were synthesized. • The photocatalytic activity of the films was improved by UV irradiation. • The photocatalytic activity of the films was comparable with that of the corresponding powders. - Abstract: Graphene oxide (GO) sheets with a low concentration (∼1 wt%) were deposited on surface of hydrothermally synthesized ZnO nanorod films. The deposited films were heat treated at 450 °C in order to achieve suitable GO/ZnO hybrid thin films for photocatalytic purposes. The photocatalytic activity of the nanocomposite films was investigated based on degradation of methylene blue (MB) dye which is a typical pollutant model. The GO/ZnO hybrid thin films could degrade higher MB (∼90%) than the bare ZnO nanorods (which showed only ∼75% degradation) after 450 min UV irradiation. A further significant improvement (resulting in a nearly complete degradation of MB) was achieved by exposing the GO/ZnO films to UV irradiation. The improvement was assigned to UV-assisted photocatalytic reduction of GO sheets and separation of photoexcited electron-hole pairs of ZnO by the UV-treated GO sheets. These results highlight application of UV treatment in improving the photocatalytic activity of GO-containing ZnO nanostructures.

  5. Visible-blind ultraviolet photodiode fabricated by UV oxidation of metallic zinc on p-Si

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongyuan; Uchida, Kazuo; Nozaki, Shinji, E-mail: nozaki@ee.uec.ac.jp [Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu-shi, Tokyo 182-8585 (Japan)

    2015-09-07

    A UV photodiode fabricated by the UV oxidation of a metallic zinc thin film on p-Si has manifested unique photoresponse characteristics. The electron concentration found by the Hall measurement was 3 × 10{sup 16 }cm{sup −3}, and such a low electron concentration resulted in a low visible photoluminescence. UV illumination enhances the oxidation at low temperatures and decreases the concentration of the oxygen vacancies. The I-V characteristic showed a good rectification with a four-order magnitude difference in the forward and reverse currents at 2 V, and its linear and frequency independent C{sup −2}–V characteristic confirmed an abrupt pn junction. The photoresponse showed a visible blindness with a responsivity ratio of UV and visible light as high as 100. Such a visible-blind photoresponse was attributed to the optimum thickness of the SiO{sub 2} formed on the Si surface during the UV oxidation at 400 °C. A lower potential barrier to holes at the ZnO/SiO{sub 2} interface facilitates Fowler-Nordheim tunneling of the photo-generated holes during the UV illumination, while a higher potential barrier to electrons efficiently blocks transport of the photo-generated electrons to the ZnO during the visible light illumination. The presence of oxide resulted in a slow photoresponse to the turn-on and off of the UV light. A detailed analysis is presented to understand how the photo-generated carriers contribute step by step to the photocurrent. In addition to the slow photoresponse associated with the SiO{sub 2} interfacial layer, the decay of the photocurrent was found extremely slow after turn-off of the UV light. Such a slow decay of the photocurrent is referred to as a persistent photoconductivity, which is caused by metastable deep levels. It is hypothesized that Zn vacancies form such a deep level, and that the photo-generated electrons need to overcome a thermal-energy barrier for capture. The ZnO film by the UV oxidation at 400 °C was found

  6. A UV-sensitive syndrome patient with a specific CSA mutation reveals separable roles for CSA in response to UV and oxidative DNA damage.

    Science.gov (United States)

    Nardo, Tiziana; Oneda, Roberta; Spivak, Graciela; Vaz, Bruno; Mortier, Laurent; Thomas, Pierre; Orioli, Donata; Laugel, Vincent; Stary, Anne; Hanawalt, Philip C; Sarasin, Alain; Stefanini, Miria

    2009-04-14

    UV-sensitive syndrome (UV(S)S) is a recently-identified autosomal recessive disorder characterized by mild cutaneous symptoms and defective transcription-coupled repair (TC-NER), the subpathway of nucleotide excision repair (NER) that rapidly removes damage that can block progression of the transcription machinery in actively-transcribed regions of DNA. Cockayne syndrome (CS) is another genetic disorder with sun sensitivity and defective TC-NER, caused by mutations in the CSA or CSB genes. The clinical hallmarks of CS include neurological/developmental abnormalities and premature aging. UV(S)S is genetically heterogeneous, in that it appears in individuals with mutations in CSB or in a still-unidentified gene. We report the identification of a UV(S)S patient (UV(S)S1VI) with a novel mutation in the CSA gene (p.trp361cys) that confers hypersensitivity to UV light, but not to inducers of oxidative damage that are notably cytotoxic in cells from CS patients. The defect in UV(S)S1VI cells is corrected by expression of the WT CSA gene. Expression of the p.trp361cys-mutated CSA cDNA increases the resistance of cells from a CS-A patient to oxidative stress, but does not correct their UV hypersensitivity. These findings imply that some mutations in the CSA gene may interfere with the TC-NER-dependent removal of UV-induced damage without affecting its role in the oxidative stress response. The differential sensitivity toward oxidative stress might explain the difference between the range and severity of symptoms in CS and the mild manifestations in UV(s)S patients that are limited to skin photosensitivity without precocious aging or neurodegeneration.

  7. UV-B-induced Oxidative Damage and Protective Role of Exopolysaccharides in Desert Cyanobacterium Microcoleus vaginatus

    Institute of Scientific and Technical Information of China (English)

    Lan-Zhou Chen; Gao-Hong Wang; Song Hong; An Liu; Cheng Li; Yong-Ding Liu

    2009-01-01

    UV-B-induced oxidative damage and the protective effect of exopolysaccharides (EPS) in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiation, photosynthetic activity (Fv/Fm), cellular total carbohydrates, EPS and sucrose production of irradiated cells decreased, while reducing sugars, reactive oxygen species (ROS) generation, malondialdehyde (MDA) production and DNA strand breaks increased significantly. However, when pretreated with 100 mg/L exogenous EPS, EPS production in the culture medium of UV-B stressed cells decreased significantly; Fv/Fm, cellular total carbohydrates, reducing sugars and sucrose synthase (SS) activity of irradiated cells increased significantly, while ROS generation, MDA production and DNA strand breaks of irradiated cells decreased significantly. The results suggested that EPS exhibited a significant protective effect on DNA strand breaks and lipid peroxidation by effectively eliminating ROS induced by UV-B radiation in M. vaginatus.

  8. In-situ investigation of graphene oxide under UV irradiation: Evolution of work function

    Directory of Open Access Journals (Sweden)

    Jun Li

    2015-06-01

    Full Text Available Using in-situ Kelvin probe force microscopy (KPFM to measure surface potential, we investigated the time-dependent work function evolution of solution-processed graphene oxide (GO under ultraviolet (UV irradiation. We found that the work function of GO exposed in UV shows a notable decrease with increasing irradiation time, which is proposed to be attributed to the gradual disappearance of oxygen-containing functional groups in GO during the UV-induced reduction reaction process. Fourier transform infrared spectrum and Raman spectrum were used to confirm the reduction of GO under UV irradiation. Our study would give an insight into understanding the transformation of GO’s electronic structures during the reduction process.

  9. Effect of UV exposure on photochromic glasses doped with transition metal oxides

    Science.gov (United States)

    El-Zaiat, S. Y.; Medhat, M.; Omar, Mona F.; Shirif, Marwa A.

    2016-07-01

    Silver halide photochromic glasses doped with one of the transition metal oxides, (Ti O2) , (CoO) ,(Cr2 O3) are prepared using the melt quench technique. Glass samples are exposed to a UV source for 20 min. Spectral reflectance and transmittance at normal incidence of the prepared glasses are recorded before and after UV exposure with a double beam spectrophotometer in the spectral range 200-2500 nm. Dispersion parameters such as: single oscillator energy, dispersion energy and Abbe's number are deduced and compared. Absorption dispersion parameters, like optical energy gap for direct and indirect transitions, Urbach energy and steepness parameter, are deduced for the different glass prepared. Reflection loss, molar refractivity and electronic polarizability are deduced and compared. The effect of UV light exposure of these glasses on transmittance, reflectance, the linear and the predicted nonlinear optical parameters are investigated and discussed for the three transition metals. Nonlinear parameters increase in the three glass samples after UV exposure.

  10. Long-term variability and impact on human health of biologically active UV radiation in Moscow

    Science.gov (United States)

    Zhdanova, Ekaterina; Chubarova, Natalia

    2014-05-01

    Measurements of erythemally weighted UV irradiance (Qer) have been performed at the Meteorological Observatory of Moscow State University since 1999 with the UVB-1 YES pyranometers. These types of devices are broadband with a spectral sensitivity curve close to the action spectrum of erythema. Main uncertainties of UVB-1 YES measurements include the difference in spectral curves of the instrument and the action spectrum of erythema, as well as the deviation from the cosine law. These uncertainties were taken into account in the database of Qer measurements (Chubarova, 2008. Additional corrections of UVB-1 measurements at low ambient temperatures have been made. We analyze interannual, seasonal and diurnal Qer changes over the time period 1999-2012. In addition, the comparisons with the results of UV reconstruction model (Chubarova, 2008) are made. This model allows us to evaluate relative changes in Qer due to variations in total ozone, effective cloud amount transmission, aerosol and cloud optical thickness since 1968. It is important to note that the main reason for UV irradiance monitoring development is the strong influence of UV irradiance on the biosphere and especially on human health mainly on human skin (CIE, 1993, CIE, 2006) and eyes (Oriowo, M. et al., 2001). Based on the detailed studies we have shown the possibility of utilizing UVB-1 pyranometers for measuring the eye-damage UV radiation. Parallel measurements by the Bentham DTM-300 spectrometer and the UVB-1 YES pyranometer at the Innsbruck Medical University (Austria) have provided us the calibration factor in eye-damage units for this broadband instrument. Influence of main geophysical factors on different types of UV irradiance is estimated by means the RAF ideology (Booth, Madronich, 1994). We discuss the responses of different types of biologically active UV radiation to the impact of various atmospheric factors. The UV conditions (deficiency, optimum, excess for human) are analyzed according to

  11. Review of photochemical reaction constants of organic micropollutants required for UV advanced oxidation processes in water.

    Science.gov (United States)

    Wols, B A; Hofman-Caris, C H M

    2012-06-01

    Emerging organic contaminants (pharmaceutical compounds, personal care products, pesticides, hormones, surfactants, fire retardants, fuel additives etc.) are increasingly found in water sources and therefore need to be controlled by water treatment technology. UV advanced oxidation technologies are often used as an effective barrier against organic contaminants. The combined operation of direct photolysis and reaction with hydroxyl radicals ensures good results for a wide range of contaminants. In this review, an overview is provided of the photochemical reaction parameters (quantum yield, molar absorption, OH radical reaction rate constant) of more than 100 organic micropollutants. These parameters allow for a prediction of organic contaminant removal by UV advanced oxidation systems. An example of contaminant degradation is elaborated for a simplified UV/H(2)O(2) system.

  12. Biodegradability of iopromide products after UV/H₂O₂ advanced oxidation.

    Science.gov (United States)

    Keen, Olya S; Love, Nancy G; Aga, Diana S; Linden, Karl G

    2016-02-01

    Iopromide is an X-ray and MRI contrast agent that is virtually non-biodegradable and persistent through typical wastewater treatment processes. This study determined whether molecular transformation of iopromide in a UV/H2O2 advanced oxidation process (AOP) can result in biodegradable products. The experiments used iopromide labeled with carbon-14 on the aromatic ring to trace degradation of iopromide through UV/H2O2 advanced oxidation and subsequent biodegradation. The biotransformation assay tracked the formation of radiolabeled (14)CO2 which indicated full mineralization of the molecule. The results indicated that AOP formed biodegradable iopromide products. There was no (14)C released from the pre-AOP samples, but up to 20% of all radiolabeled carbon transformed into (14)CO2 over the course of 42 days of biodegradation after iopromide was exposed to advanced oxidation (compared to 10% transformation in inactivated post-AOP controls). In addition, the quantum yield of photolysis of iopromide was determined using low pressure (LP) and medium pressure (MP) mercury lamps as 0.069 ± 0.005 and 0.080 ± 0.007 respectively. The difference in the quantum yields for the two UV sources was not statistically significant at the 95% confidence interval (p = 0.08), which indicates the equivalency of using LP or MP UV sources for iopromide treatment. The reaction rate between iopromide and hydroxyl radicals was measured to be (2.5 ± 0.2) × 10(9) M(-1) s(-1). These results indicate that direct photolysis is a dominant degradation pathway in UV/H2O2 AOP treatment of iopromide. Other iodinated contrast media may also become biodegradable after exposure to UV or UV/H2O2.

  13. Characterization of solid UV curable 3D printer resins for biological applications

    KAUST Repository

    Sivashankar, Shilpa

    2016-12-19

    In this paper, we report a simple method to evaluate biocompatibility of solid UV cross-linked resin as a material for microfluidic devices that can be used for biological applications. We evaluated the biocompatibility of the material in two different ways (1) determining if the UV cured resin inhibits the polymerase chain reaction (PCR) and (2) observing agglutination complex formed on the surface of the UV cured resin when anti-CRP antibodies and C- reactive protein (CRP) proteins were allowed to agglutinate. Six different types of 3D printer resins were compared to test the biocompatibility. The study showed that only few among them could be used for fabrication of micro channels and that had least effect on biological molecules that could be used for PCR and protein interactions. Through these studies it is possible to estimate the curing time of various resin and their type of interaction with biomolecules. This study finds importance in on-chip tissue engineering and organ-on-chip applications.

  14. Biological treatment with fungi of olive mill wastewater pre-treated by photocatalytic oxidation with nanomaterials.

    Science.gov (United States)

    Nogueira, V; Lopes, I; Freitas, A C; Rocha-Santos, T A P; Gonçalves, F; Duarte, A C; Pereira, R

    2015-05-01

    Olive mill wastewater (OMW) still is a major environmental problem due to its high chemical oxygen demand (COD) and total phenolic content (TPC), contributing for the high toxicity and recalcitrant nature. Several attempts have been made for developing more efficient treatment processes, but no chemical or biological approaches were found to be totally effective, especially in terms of toxicity reduction. In this context, the main purpose of this study was to investigate the treatability of OMW by the combination of photocatalytic oxidation, using two nanomaterials as catalysts (TiO2 and Fe2O3), with biological degradation by fungi (Pleurotus sajor caju and Phanerochaete chrysosporium). Photocatalytic oxidation was carried out using different systems, nano-TiO2/UV, nano-Fe2O3/UV, nano-TiO2/H2O2/UV and nano-Fe2O3/H2O2/UV. The effectiveness of the treatment was assessed through color (465nm), aromatics (270nm), COD and TPC reductions, as well as by the decrease in toxicity using the bacterium Vibrio fischeri. The chemical treatment with the system nano-TiO2/H2O2/UV promoted 43%, 14%, 38% and 31% reductions in color, aromatics content, COD and TPC, respectively. However no toxicity reduction was observed. The combination with a biological treatment increased the reduction of COD and TPC as well as a reduction in toxicity. The treatment with P. chrysosporium promoted the highest reduction in toxicity, but P. sajor caju was responsible for the best reduction in COD and TPC. However, the biological treatment was more effective when no hydrogen peroxide was used in the pre-treatment.

  15. H2O2/UV Photo-Oxidation of Gadung (Dioscorea Hispida Dennst. Starch and its Product Physicochemical Characterization

    Directory of Open Access Journals (Sweden)

    Andri Cahyo Kumoro

    2016-08-01

    Full Text Available This work aimed to study the preparation and physicochemical properties characterization of oxidized gadung starch obtained from oxidation process implementing combined H2O2-UV irradiation. The photo-oxidation process was carried out in a well-mixed slurry reaction system at ambient temperature. The extent of oxidation was determined based on the carboxyl and the carbonyl contents of the oxidized gadung starch. The results show that oxidation process altered the carbonyl and carboxyl contents of the starch. Except the morphology of the starch, the swelling power, solubility and gelatinization temperature of the starch were severely affected by H2O2/UV oxidation process.

  16. Energy Effectiveness of Direct UV and UV/H2O2 Treatment of Estrogenic Chemicals in Biologically Treated Sewage

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2012-01-01

    and the UV/H2O2-treatment were investigated in biologically treated sewage for most of the estrogenic compounds reported in wastewater. The investigated compounds included parabens, industrial phenols, sunscreen chemicals and steroid estrogens. Treatment experiments were performed in a flow through set...

  17. Decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2 and UV/TiO2 oxidation processes.

    Science.gov (United States)

    Yan, Yingjie; Liao, Qi-Nan; Ji, Feng; Wang, Wei; Yuan, Shoujun; Hu, Zhen-Hu

    2017-02-01

    3,5-Dinitrobenzamide has been widely used as a feed additive to control coccidiosis in poultry, and part of the added 3,5-dinitrobenzamide is excreted into wastewater and surface water. The removal of 3,5-dinitrobenzamide from wastewater and surface water has not been reported in previous studies. Highly reactive hydroxyl radicals from UV/hydrogen peroxide (H2O2) and UV/titanium dioxide (TiO2) advanced oxidation processes (AOPs) can decompose organic contaminants efficiently. In this study, the decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2 and UV/TiO2 oxidation processes was investigated. The decomposition of 3,5-dinitrobenzamide fits well with a fluence-based pseudo-first-order kinetics model. The decomposition in both two oxidation processes was affected by solution pH, and was inhibited under alkaline conditions. Inorganic anions such as NO3(-), Cl(-), SO4(2-), HCO3(-), and CO3(2-) inhibited the degradation of 3,5-dinitrobenzamide during the UV/H2O2 and UV/TiO2 oxidation processes. After complete decomposition in both oxidation processes, approximately 50% of 3,5-dinitrobenzamide was decomposed into organic intermediates, and the rest was mineralized to CO2, H2O, and other inorganic anions. Ions such as NH4(+), NO3(-), and NO2(-) were released into aqueous solution during the degradation. The primary decomposition products of 3,5-dinitrobenzamide were identified using time-of-flight mass spectrometry (LCMS-IT-TOF). Based on these products and ions release, a possible decomposition pathway of 3,5-dinitrobenzamide in both UV/H2O2 and UV/TiO2 processes was proposed.

  18. Direct Oxidative Damage of Naked DNA Generated upon Absorption of UV Radiation by Nucleobases.

    Science.gov (United States)

    Gomez-Mendoza, Miguel; Banyasz, Akos; Douki, Thierry; Markovitsi, Dimitra; Ravanat, Jean-Luc

    2016-10-06

    It has been shown that in addition to formation of pyrimidine dimers, UV irradiation of DNA in the absence of photosensitizer also induces formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine, but the mechanism of formation of that oxidized base has not been clearly established. In the present study, we provide an unambiguous demonstration that absorption of UVC and UVB radiation by the nucleobases induces DNA oxidation via a direct process (one-electron oxidation) and not singlet oxygen. Evidence arose from the fact that polyamine-guanine adducts that are specifically produced through the transient formation of guanine radical cation are generated following UV irradiation of DNA in the presence of a polyamine even in the absence of any photosensitizer.

  19. Andrographolide Sodium Bisulfate Prevents UV-Induced Skin Photoaging through Inhibiting Oxidative Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Janis Ya-Xian Zhan

    2016-01-01

    Full Text Available Andrographolide sodium bisulfate (ASB, a water-soluble form made from andrographolide through sulfonating reaction, is an antioxidant and anti-inflammatory drug; however, the antiphotoaging effect of ASB has still not been revealed. Oxidative stress and inflammation are known to be responsible for ultraviolet (UV irradiation induced skin damage and consequently premature aging. In this study, we aimed at examining the effect of ASB on UV-induced skin photoaging of mice by physiological and histological analysis of skin and examination of skin antioxidant enzymes and immunity analyses. Results showed that topical administration of ASB suppressed the UV-induced skin thickness, elasticity, wrinkles, and water content, while ASB, especially at dose of 3.6 mg/mouse, increased the skin collagen content by about 53.17%, decreased the epidermal thickness by about 41.38%, and prevented the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, ASB decreased MDA level by about 40.21% and upregulated the activities of SOD and CAT and downregulated the production of IL-1β, IL-6, IL-10, and TNF-α in UV-irradiated mice. Our study confirmed the protective effect of ASB against UV-induced photoaging and initially indicated that this effect can be attributed to its antioxidant and anti-inflammatory activities in vivo, suggesting that ASB may be a potential antiphotoaging agent.

  20. H₂S photocatalytic oxidation over WO₃/TiO₂ Hombikat UV100.

    Science.gov (United States)

    Alonso-Tellez, Angela; Robert, Didier; Keller, Valérie; Keller, Nicolas

    2014-03-01

    Hydrogen sulfide (H2S) is a toxic, corrosive and malodorous compound with damaging effects even when present at a low concentration in air. Consequently, the development of efficient and environmentally friendly remediation technologies as an alternative to conventional techniques is justified for environmental reasons and public concern over human health and well-being. In the context of indoor air quality control, the use of photocatalysis over semi-conductor oxides could be a valuable alternative purification technology due to its wide-ranging effect and its easy way of implementation. The superiority of the TiO2 Hombikat UV100 photocatalyst in comparison with the Aeroxide© TiO2 P25 standard was already apparent in the UV-A photocatalytic oxidation of H2S. We report here on the first use of WO3/TiO2 UV100 photocatalysts for this reaction. Associating WO3 to TiO2 UV100 was not beneficial in terms of semiconductor coupling and of charge transfer between both phases. Even if such coupled wide band-gap oxide semi-conductor photocatalysts suffered from on-flow deactivation due to the formation of poisoning sulfates as ultimate reaction products continuously stored at the surface, by contrast, their ability to strongly lower and delay the release of SO2 to the gas phase was very positive for maintaining a weak selectivity into the unwanted SO2 by-product.

  1. Treatment of Remazol Brilliant Blue Dye Effluent by Advanced Photo Oxidation Process in TiO2/UV and H2O2/UV reactors

    Directory of Open Access Journals (Sweden)

    M. Verma

    2008-01-01

    Full Text Available Advanced oxidation processes involving TiO2/UV and H2O2/UV were evaluated for their potential use in decolorization of textile dye effluents. A coil photo reactor, consisting of UV radiation source and a spiral coil coated with TiO2, was used to treat synthetic effluent of Remazol Brilliant Blue dye. The TiO2 coating was performed using the sol-gel technique. The effects of UV radiation, TiO2 coatings and dye concentration were studied and the results were compared to dye treatment involving H2O2. The maximum dye removal efficiencies were 7.3, 12.2 and 12.5 % for uncoated, single coat and dual coat of TiO2, respectively. The decolorization efficiency was inversely related to dye concentration of the effluent. The treatments with UV only, TiO2 only, UV+TiO2, H2O2 only and UV+H2O2 resulted in color reduction of 7.6, 2.3, 12.5, 4.1 and 99.9 % respectively. The maximum decolorization occurred in ≤ 100 min in all cases. The temperature varied from 29.2 to 54.7°C for UV+TiO2 treatment and no change in reactor temperature was observed when UV was not used.

  2. Characterization of solid UV cross-linked PEGDA for biological applications

    KAUST Repository

    Castro, David

    2013-10-20

    This paper reports on solid UV cross-linked Poly(ethylene)-glycol-diacrylate (PEGDA) as a material for microfluidic devices for biological applications. We have evaluated biocompatibility of PEGDA through two separate means: 1) by examining cell viability and attachment on cross-linked PEGDA surfaces for cell culture applications, and 2) by determining if cross-linked PEGDA inhibits the polymerase chain reaction (PCR) processes for on-chip PCR. Through these studies a correlation has been found between degree of curing and cell viability, attachment, as well as on PCR outcome.

  3. Photocatalytic Oxidation of Gaseous Benzene under 185 nm UV Irradiation

    OpenAIRE

    Haibao Huang; Xinguo Ye; Huiling Huang; Peng Hu; Lu Zhang; Leung, Dennis Y. C.

    2013-01-01

    Benzene is a toxic air pollutant and causes great harm to human being. Photocatalytic oxidation (PCO) has been frequently studied for benzene removal, however, its PCO efficiency is still very low and the photocatalysts are easy to be deactivated. To improve the efficiency and stability of PCO, UV lamps with partial 185 nm UV irradiation were used to activate photocatalysts (denoted as 185-PCO). Cobalt modified TiO2 (Co-TiO2) was developed to improve the PCO activity and eliminate ozone gener...

  4. UV optical properties of thin film oxide layers deposited by different processes.

    Science.gov (United States)

    Pellicori, Samuel F; Martinez, Carol L

    2011-10-01

    UV optical properties of thin film layers of compound and mixed oxide materials deposited by different processes are presented. Japan Electron Optics Laboratory plasma ion assisted deposition (JEOL PIAD), electron beam with and without IAD, and pulsed DC magnetron sputtering were used. Comparisons are made with published deposition process data. Refractive indices and absorption values to as short as 145 nm were measured by spectroscopic ellipsometry (SE). Electronic interband defect states are detected that are deposition-process dependent. SE might be effective in identifying UV optical film quality, especially in defining processes and material composition beneficial for high-energy excimer laser applications and environments requiring stable optical properties.

  5. UV-based advanced oxidation processes for the treatment of odour compounds: efficiency and by-product formation.

    Science.gov (United States)

    Zoschke, Kristin; Dietrich, Norman; Börnick, Hilmar; Worch, Eckhard

    2012-10-15

    The occurrence of the taste and odour compounds geosmin and 2-methyl isoborneol (2-MIB) affects the organoleptic quality of raw waters from drinking water reservoirs worldwide. UV-based oxidation processes for the removal of these substances are an alternative to adsorption and biological processes, since they additionally provide disinfection of the raw water. We could show that the concentration of geosmin and 2-MIB could be reduced by VUV irradiation and the combination of UV irradiation with ozone and hydrogen peroxide in pure water and water from a drinking water reservoir. The figure of merit EE/O is an appropriate tool to compare the AOPs and showed that VUV and UV/O(3) yielded the lowest treatment costs for the odour compounds in pure and raw water, respectively. Additionally, VUV irradiation with addition of ozone, generated by the VUV lamp, was evaluated. The generation of ozone and the irradiation were performed in a single reactor system using the same low-pressure mercury lamp, thereby reducing the energy consumption of the treatment process. The formation of the undesired by-products nitrite and bromate was investigated. The combination of VUV irradiation with ozone produced by a VUV lamp avoided the formation of relevant concentrations of the by-products. The internal generation of ozone is capable to produce ozone concentrations sufficient to reduce EE/O below 1 kWh m(-3) and without the risk of the formation of nitrite or bromate above the maximum contaminant level.

  6. UV/Fenton photo-oxidation of Drimarene Dark Red (DDR) containing textile-dye wastewater

    Science.gov (United States)

    Hudaya, T.; Anthonios, J.; Septianto, E.

    2016-11-01

    Textile dye wastewater contains organic pollutants which are non-biodegradable, characterized by low BOD/COD ratio of typically treat such wastewater, the destructive wastewater treatment methods which can be utilized are the Advanced Oxidation Processes (AOPs). One of the AOPs method which is the UV/H2O2/Fe2+ (or UV/Fenton) offers not only relatively low cost but also quite effective (in terms of color removal and reaction time) treatment. This particular research aimed to optimize the conditions of UV/Fenton photo-oxidation process for Drimarene Dark Red containing textile- dye wastewater. The two main operating conditions to be optimized were the initial concentration of H2O2 ranged between 0.022-0.078 %-w and the mol ratio of Fe2+: H2O2 was varied from 1: 13 up to 1: 45, using the Central Composite Design experimental matrix. The photo-oxidation was carried out at the optimum pH of 3 from some previous experiments. The best processing conditions of the photo-oxidation of Drimarene Dark Red (DDR) were found at the initial concentration of H2O2 at 0.050%-w and the mole ratio Fe2+: H2O2 of 1: 22. Under these conditions, the measured 2nd order pseudo-rate constantwas 0.021 M-1.min-1. The DDR color removal of 90% was surprisingly achievable within only 10 minutes reaction time.

  7. UV-assisted rapid thermal annealing for solution-processed zinc oxide thin-film transistors

    Science.gov (United States)

    Hwang, Jaeeun; Park, Jaehoon; Kim, Hongdoo

    2014-09-01

    An ultraviolet (UV)-assisted thermal annealing (TA) method is proposed for the rapid fabrication of solution-processed zinc oxide (ZnO) thin-film transistors (TFTs). Conventional thermal treatment of zinc hydroxide solution, which was carried out at 150 °C for 60 min in air, produced ZnO materials. Electrical properties of the TFTs employing thermally-annealed ZnO films were reproduced in the transistors fabricated using a simultaneous thermal treatment combined with UV irradiation at 150 °C for 3 min in air. These results demonstrate that the UV-assisted TA method can expedite the decomposition of precursor materials, contributing to rapid crystallization into thin films.

  8. Robust superhydrophobic tungsten oxide coatings with photochromism and UV durability properties

    Science.gov (United States)

    Jiang, Ting; Guo, Zhiguang

    2016-11-01

    Robust superhydrophobic tungsten oxide (TO) coatings with a water contact angle (WCA) of 155° were developed for photochromism via a facile and substrate-independent route. Importantly, after scatch test on both a single and two orthogonal direction, the TO coating still exhibited superhydrophobic behavior, indicating excellent mechanical robustness. It is worth mentioning that the superhydrophobic TO coatings showed the reversible convert of photochromism of WO3 induced by alternating UV and visible light irradiation. Besides that, the TO coating remained superhydrophobicity after UV irradiation for 36 h, showing excellent UV durability. In addition, the coating showed good resistance to acidic droplets. Moreover, it can also be applied on other substrates, such as copper mesh, steel, paper and fiber. The coating exhibited excellent self-cleaning behavior due to its high WCA and low rolling angle. Overall, this work is a promising approach to design and produce functional superhydrophobic coatings for various substrates.

  9. Contrasting patterns of tolerance between chemical and biological insecticides in mosquitoes exposed to UV-A.

    Science.gov (United States)

    Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Raveton, Muriel; Reynaud, Stéphane

    2013-09-15

    Mosquitoes are vectors of major human diseases, such as malaria, dengue or yellow fever. Because no efficient treatments or vaccines are available for most of these diseases, control measures rely mainly on reducing mosquito populations by the use of insecticides. Numerous biotic and abiotic factors are known to modulate the efficacy of insecticides used in mosquito control. Mosquito breeding sites vary from opened to high vegetation covered areas leading to a large ultraviolet gradient exposure. This ecological feature may affect the general physiology of the insect, including the resistance status against insecticides. In the context of their contrasted breeding sites, we assessed the impact of low-energetic ultraviolet exposure on mosquito sensitivity to biological and chemical insecticides. We show that several mosquito detoxification enzyme activities (cytochrome P450, glutathione S-transferases, esterases) were increased upon low-energy UV-A exposure. Additionally, five specific genes encoding detoxification enzymes (CYP6BB2, CYP6Z7, CYP6Z8, GSTD4, and GSTE2) previously shown to be involved in resistance to chemical insecticides were found over-transcribed in UV-A exposed mosquitoes, revealed by RT-qPCR experiments. More importantly, toxicological bioassays revealed that UV-exposed mosquitoes were more tolerant to four main chemical insecticide classes (DDT, imidacloprid, permethrin, temephos), whereas the bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) appeared more toxic. The present article provides the first experimental evidence of the capacity of low-energy UV-A to increase mosquito tolerance to major chemical insecticides. This is also the first time that a metabolic resistance to chemical insecticides is linked to a higher susceptibility to a bioinsecticide. These results support the use of Bti as an efficient alternative to chemical insecticides when a metabolic resistance to chemicals has been developed by mosquitoes.

  10. Enhanced biodegradation of carbamazepine after UV/H2O2 advanced oxidation.

    Science.gov (United States)

    Keen, Olya S; Baik, Seungyun; Linden, Karl G; Aga, Diana S; Love, Nancy G

    2012-06-05

    Carbamazepine is one of the most persistent pharmaceutical compounds in wastewater effluents due to its resistance to biodegradation-based conventional treatment. Advanced oxidation can efficiently degrade carbamazepine, but the toxicity and persistence of the oxidation products may be more relevant than the parent. This study sets out to determine whether the products of advanced oxidation of carbamazepine can be biotransformed and ultimately mineralized by developing a novel methodology to assess these sequential treatment processes. The methodology traces the transformation products of the (14)C-labeled carbamazepine during UV/hydrogen peroxide advanced oxidation and subsequent biotransformation by mixed, undefined cultures using liquid scintillation counting and liquid chromatography with radioactivity, mass spectrometry, and UV detectors. The results show that the oxidation byproducts of carbamazepine containing a hydroxyl or carbonyl group can be fully mineralized by a mixed bacterial inoculum. A tertiary treatment approach that includes oxidation and biotransformation has the potential to synergistically mineralize persistent pharmaceutical compounds in wastewater treatment plant effluents. The methodology developed for this study can be applied to assess the mineralization potential of other persistent organic contaminants.

  11. Biological Effects of the Great Oxidation Event

    Science.gov (United States)

    Schopf, J.

    2012-12-01

    Fossil evidence of photoautotrophy, documented in Precambrian sediments by stromatolites, stromatolitic microfossils, and carbon isotopic data consistent with autotrophic CO2-fixation, extends to ~3,500 Ma. Such data, however, are insufficient to establish the time of origin of O2-producing (cyanobacterial) photosynthesis from its anoxygenic, photosynthetic bacterial, evolutionary precursor. The oldest (Paleoarchean) stromatolites may have been formed by anoxygenic photoautotrophs, rather than the cyanobacteria that dominate Proterozoic and modern stromatolites. Unlike the cyanobacteria of Proterozoic microbial assemblages, the filamentous and coccoidal microfossils of Archean deposits may represent remnants of non-O2-producing prokaryotes. And although the chemistry of Archean organic matter shows it to be biogenic, its carbon isotopic composition is insufficient to differentiate between oxygenic and anoxygenic sources. Though it is well established that Earth's ecosystem has been based on autotrophy since its early stages and that O2-producing photosynthesis evolved earlier, perhaps much earlier, than the increase of atmospheric oxygen in the ~2,450 and ~2,320 Ma Great Oxidation Event (GOE), the time of origin of oxygenic photoautotrophy has yet to be established. Recent findings suggest that Earth's ecosystem responded more or less immediately to the GOE. The increase of atmospheric oxygen markedly affected ocean water chemistry, most notably by increasing the availability of biologically usable oxygen (which enabled the development of obligate aerobes, such as eukaryotes), and of nitrate, sulfate and hydrogen sulfide (the increase of H2S being a result of microbial reduction of sulfate), the three reactants that power the anaerobic basis of sulfur-cycling microbial sulfuretums. Fossil evidence of the earliest eukaryotes (widely accepted to date from ~1800 Ma and, arguably, ~2200 Ma) fit this scenario, but the most telling example of life's response to the GOE

  12. Photocatalytic Oxidation of Gaseous Benzene under 185 nm UV Irradiation

    Directory of Open Access Journals (Sweden)

    Haibao Huang

    2013-01-01

    Full Text Available Benzene is a toxic air pollutant and causes great harm to human being. Photocatalytic oxidation (PCO has been frequently studied for benzene removal, however, its PCO efficiency is still very low and the photocatalysts are easy to be deactivated. To improve the efficiency and stability of PCO, UV lamps with partial 185 nm UV irradiation were used to activate photocatalysts (denoted as 185-PCO. Cobalt modified TiO2 (Co-TiO2 was developed to improve the PCO activity and eliminate ozone generated from 185 nm UV irradiation. Results show that benzene removal efficiency of PCO with 254 nm UV irradiation (denoted as 254-PCO is only 2.1% while it was greatly increased to 51.5% in 185-PCO. 185-PCO exhibited superior capacity for benzene oxidation. In the 185-PCO process, much ozone was left in case of TiO2 as photocatalysts while it can be nearly eliminated by 1% Co-TiO2.

  13. Detection of UV-induced mutagenic thymine dimer using graphene oxide.

    Science.gov (United States)

    Chung, Chan Ho; Kim, Joong Hyun; Chung, Bong Hyun

    2014-12-02

    In this paper, we report for the first time that graphene oxide (GO) can interact with mutagenic DNA but not intact DNA. After UV-irradiated fluorophore-linked DNA containing thymine repeats was mixed with GO, a decrease in fluorescence was observed in a time-dependent manner. In contrast, no fluorescence change was observed with intact DNA, indicating that UV irradiation of DNA resulted in the formation of mutagenic bases. Because GO is known to act as a fluorescence quencher, the decreased fluorescence implies adsorption of the UV-irradiated DNA onto GO. It appears that the decreased fluorescence might result from the greater accessibility of hydrophobic methyl groups and phenyl rings of thymine dimers to GO and from deformed DNA structures with less effective charge shielding under salt-containing conditions. Using this affinity of GO for mutagenic DNA, we could detect UV-irradiated DNA at concentrations as low as 100 pM. We were also able to analyze the ability of phototoxic drugs to catalyze the formation of mutagens under UV irradiation with GO. Because our method is highly sensitive and feasible and does not require the pretreatment of DNA, we propose that it could accelerate the screening of potential phototoxic drug candidates that would be able to sensitize mutagenic dsDNA.

  14. Degradation of oxcarbazepine by UV-activated persulfate oxidation: kinetics, mechanisms, and pathways.

    Science.gov (United States)

    Bu, Lingjun; Zhou, Shiqing; Shi, Zhou; Deng, Lin; Li, Guangchao; Yi, Qihang; Gao, Naiyun

    2016-02-01

    The degradation kinetics and mechanism of the antiepileptic drug oxcarbazepine (OXC) by UV-activated persulfate oxidation were investigated in this study. Results showed that UV/persulfate (UV/PS) process appeared to be more effective in degrading OXC than UV or PS alone. The OXC degradation exhibited a pseudo-first order kinetics pattern and the degradation rate constants (k obs) were affected by initial OXC concentration, PS dosage, initial pH, and humic acid concentration to different degrees. It was found that low initial OXC concentration, high persulfate dosage, and initial pH enhanced the OXC degradation. Additionally, the presence of humic acid in the solution could greatly inhibit the degradation of OXC. Moreover, hydroxyl radical (OH•) and sulfate radical (SO4 (-)••) were identified to be responsible for OXC degradation and SO4 (-)• made the predominant contribution in this study. Finally, major intermediate products were identified and a preliminary degradation pathway was proposed. Results demonstrated that UV/PS system is a potential technology to control the water pollution caused by emerging contaminants such as OXC.

  15. Improving the photocatalytic activity of graphene oxide/ZnO nanorod films by UV irradiation

    Science.gov (United States)

    Rokhsat, Eliza; Akhavan, Omid

    2016-05-01

    Graphene oxide (GO) sheets with a low concentration (∼1 wt%) were deposited on surface of hydrothermally synthesized ZnO nanorod films. The deposited films were heat treated at 450 °C in order to achieve suitable GO/ZnO hybrid thin films for photocatalytic purposes. The photocatalytic activity of the nanocomposite films was investigated based on degradation of methylene blue (MB) dye which is a typical pollutant model. The GO/ZnO hybrid thin films could degrade higher MB (∼90%) than the bare ZnO nanorods (which showed only ∼75% degradation) after 450 min UV irradiation. A further significant improvement (resulting in a nearly complete degradation of MB) was achieved by exposing the GO/ZnO films to UV irradiation. The improvement was assigned to UV-assisted photocatalytic reduction of GO sheets and separation of photoexcited electron-hole pairs of ZnO by the UV-treated GO sheets. These results highlight application of UV treatment in improving the photocatalytic activity of GO-containing ZnO nanostructures.

  16. Radical-free biology of oxidative stress

    OpenAIRE

    2008-01-01

    Free radical-induced macromolecular damage has been studied extensively as a mechanism of oxidative stress, but large-scale intervention trials with free radical scavenging antioxidant supplements show little benefit in humans. The present review summarizes data supporting a complementary hypothesis for oxidative stress in disease that can occur without free radicals. This hypothesis, which is termed the “redox hypothesis,” is that oxidative stress occurs as a consequence of disruption of thi...

  17. Methylene blue photocatalysis in the presence of bismuth oxide under UV and solar light irradiation

    Directory of Open Access Journals (Sweden)

    Vanessa Rocha Liberatti

    2014-05-01

    Full Text Available Bismuth oxide (Bi2O3, an n-type semiconductor has been satisfactorily investigated for photocatalytic organic contaminant remediation. The Bi2O3 was prepared by solution combustion synthesis (SCS using as the oxidizing bismuth nitrate in acidic medium and urea as fuel. The influence of the type of synthesis on the photocatalytic properties of the oxide formed was investigated by XRD. From the diffractograms was verified that the materials obtained are predominantly of Bi2O3 crystals, it is possible to identify a sample with two crystalline phases, monoclinic (α-Bi2O3 and tetragonal (β-Bi2O3, and the other with only the monoclinic (α-Bi2O3. The two-phase oxide showed higher photocatalytic activity for discoloration of methylene blue under UV irradiation (60.59% and under sunlight (61.64% in 664 nm, followed kinetic law of pseudo-first order.

  18. Measurement of biological relevant UV exposure. Investigations in a dental practice; Messung der biologisch relevanten UV-Strahlenbelastung. Untersuchungen in einer Zahnarztpraxis

    Energy Technology Data Exchange (ETDEWEB)

    Braches, J.M.H.

    2001-07-01

    Light sources used in a dental treatment room were examined in order to determine their spectral output in the UV region. Using an UVX-radiometer, the polymerization curing unit and the dental operating light were identified as the sole UV sources and thus they were examined spectroradiometrically. The curing unit exhibits a moderate fraction of UV-A radiation in the wavelength region of 350-400 nm, the operating light emitted UV-A as well as UV-B radiation (280-400 nm). Both light sources were used to determine the biological effective radiation employing the DLR biofilm technology. Results show an effect on the biofilm for the polymerization curing unit only at a distance of 0.2 cm and an unrealistic long exposure period (up to 30 min), pointing to underlying mechanisms of thermal nature. Using the operating light, a dose-dependent inactivation of the DLR biofilm could be documented. A reduction of the effect could be obtained using different shielding materials (mylar foil, medical gloves). From these experiments, the mean UV radiation exposure was calculated to be 3.163 Jm{sup -2} Biofilm/h (0.045 MED/h) for the patient's oral mucosa region and 0.145 Jm{sup -2} Biofilm/h (0.002 MED/h) for the dentist's wrist region. The results point out that there is an only marginal UV radiation risk for the dentist and the patient from the light sources of a dental practice. (orig.) [German] Die in einem Behandlungsraum einer Zahnarztpraxis vorhandenen Lichtquellen wurden in Hinblick auf deren Strahlungsabgabe im UV-Bereich des elektromagnetischen Spektrums untersucht. Mittels eines UVX-Radiometers wurden zunaechst die Polymerisationsleuchte und die Behandlungsleuchte als alleinige UV-Strahlenquellen identifiziert und daraufhin spektroradiometrisch untersucht. Die Polymerisationsleuchte zeigte dabei einen moderaten Anteil an UV-A-Strahlung im Wellenlaengenbereich von 350-400 nm, die Behandlungsleuchte emittierte UV-Strahlung sowohl im UV-A- als auch im UV

  19. [Hygienic, chemical and ecotoxicological aspects of the disinfection of biologically treated waste water by ozone and UV light].

    Science.gov (United States)

    Iske, U; Nelle, T; Oberg, C; Rudolph, K U; Zander-Hauck, S

    1996-02-01

    Biologically treated waste water from two different municipal treatment plants with mainly domestic waste water on the one hand and industrial influenced waste water on the other hand was disinfected by UV-irradiation and ozonation. Hygienic, chemical and eco-toxic effects of the disinfection step were examined. It was found that by ozonation as well as by UV-irradiation the required guide and imperative values for fecal and total coliform bacteria were fulfilled. The UV-irradiation induces no changes concerning chemical waste water quality and toxic effects. In contrast to these results ozonation can lead to alterations in chemistry and toxicity depending on the waste water composition.

  20. Biological water oxidation: lessons from nature.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Moghaddam, Atefeh Nemati; Allakhverdiev, Suleyman I; Govindjee

    2012-08-01

    Hydrogen production by water splitting may be an appealing solution for future energy needs. To evolve hydrogen efficiently in a sustainable manner, it is necessary first to synthesize what we may call a 'super catalyst' for water oxidation, which is the more challenging half reaction of water splitting. An efficient system for water oxidation exists in the water oxidizing complex in cyanobacteria, algae and plants; further, recently published data on the Manganese-calcium cluster have provided details on the mechanism and structure of the water oxidizing complex. Here, we have briefly reviewed the characteristics of the natural system from the standpoint of what we could learn from it to produce an efficient artificial system. In short, to design an efficient water oxidizing complex for artificial photosynthesis, we must learn and use wisely the knowledge about water oxidation and the water oxidizing complex in the natural system. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.

  1. Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).

    Science.gov (United States)

    Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min

    2014-08-30

    The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems.

  2. Final LDRD report : development of advanced UV light emitters and biological agent detection strategies.

    Energy Technology Data Exchange (ETDEWEB)

    Figiel, Jeffrey James; Crawford, Mary Hagerott; Banas, Michael Anthony; Farrow, Darcie; Armstrong, Andrew M.; Serkland, Darwin Keith; Allerman, Andrew Alan; Schmitt, Randal L.

    2007-12-01

    We present the results of a three year LDRD project which has focused on the development of novel, compact, ultraviolet solid-state sources and fluorescence-based sensing platforms that apply such devices to the sensing of biological and nuclear materials. We describe our development of 270-280 nm AlGaN-based semiconductor UV LEDs with performance suitable for evaluation in biosensor platforms as well as our development efforts towards the realization of a 340 nm AlGaN-based laser diode technology. We further review our sensor development efforts, including evaluation of the efficacy of using modulated LED excitation and phase sensitive detection techniques for fluorescence detection of bio molecules and uranyl-containing compounds.

  3. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian; N. Mikkelsen, Teis; Ro-Poulsen, Helge

    -arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...... (mycorrhiza) or in the biomass of microbes in the soil of the root zone. However, the composition of the soil microbial community was different in the soils under ambient and reduced UV radiation after three treatment years. These results provide new insight into the negative impact of current UV-B fluxes...

  4. Assessment of UV biological spectral weighting functions for phenolic metabolites and growth responses in silver birch seedlings.

    Science.gov (United States)

    Kotilainen, Titta; Venäläinen, Tuulia; Tegelberg, Riitta; Lindfors, Anders; Julkunen-Tiitto, Riitta; Sutinen, Sirkka; O'Hara, Robert B; Aphalo, Pedro J

    2009-01-01

    In research concerning stratospheric ozone depletion, action spectra are used as biological spectral weighting functions (BSWFs) for describing the effects of UV radiation on plant responses. Our aim was to evaluate the appropriateness of six frequently used BSWFs that differ in effectiveness with increasing wavelength. The evaluation of action spectra was based on calculating the effective UV radiation doses according to 1-2) two formulations of the generalized plant action spectrum, 3) a spectrum for ultraviolet induced erythema in human skin, 4) a spectrum for the accumulation of a flavonol in Mesembryanthemum crystallinum, 5) a spectrum for DNA damage in alfalfa seedlings and 6) the plant growth action spectrum. We monitored effects of UV radiation on the concentration of individual UV absorbing metabolites and chlorophyll concentrations in leaves and growth responses of silver birch (Betula pendula) seedlings. Experiments were conducted outdoors using plastic films attenuating different parts of the UV spectrum. Chlorophyll concentrations and growth were not affected by the UV treatments. The response to UV radiation varied between and within groups of phenolics. In general, the observed responses of phenolic groups and individual flavonoids were best predicted by action spectra extending into the UV-A region with moderate effectiveness.

  5. Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2--Comparison of transformation products, ready biodegradability and toxicity.

    Science.gov (United States)

    Lutterbeck, Carlos Alexandre; Wilde, Marcelo Luís; Baginska, Ewelina; Leder, Christoph; Machado, Ênio Leandro; Kümmerer, Klaus

    2015-09-15

    The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. Prescreening experiments varying the H2O2 and TiO2 concentrations were performed in order to set the best catalyst concentrations in the UV/H2O2 and UV/TiO2 experiments, whereas the UV/Fe(2+)/H2O2 process was optimized varying the pH, Fe(2+) and H2O2 concentrations by means of the Box-Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe(2+)/H2O2 and UV/TiO2 processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H2O2 treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H2O2 treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable.

  6. Evaluation of the Potential of Brazilian Propolis against UV-Induced Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Yris Maria Fonseca

    2011-01-01

    Full Text Available This study investigated the potential use of topically and orally administered propolis extracts to prevent UV irradiation-induced oxidative stress in skin. The results illustrated that green propolis extract (GPE contained greater amounts of polyphenols, coumaric acid, drupanin, baccharin and artepillin C than did brown propolis extract (BPE. GPE showed higher antioxidant activity than BPE when the IC50 (concentration that caused 50% inhibition values were compared. Interesting, the oral treatment of hairless mice demonstrated a recovery of 30.0% for GPE and 22.8% for BPE with respect to UV irradiation-induced GSH depletion. The topical pretreatment of animals with both propolis extract solutions recovered around 14.0% of the depleted GSH. However, the employed treatments did not inhibit the increase of cutaneous proteinase secretion/activity caused by irradiation. These findings indicate that despite differences in composition and antioxidant properties, GPE and BPE both successfully prevent UV-induced GSH depletion in vivo and are both promising antioxidant systems against oxidative stress in skin. Based on these findings, complementary studies should be performed to enhance our understanding of the protective effects of propolis extracts in skin.

  7. A development and biological safety evaluation of novel PVC medical devices with surface structures modified by UV irradiation to suppress plasticizer migration.

    Science.gov (United States)

    Haishima, Yuji; Isama, Kazuo; Hasegawa, Chie; Yuba, Toshiyasu; Matsuoka, Atsuko

    2013-09-01

    This study examines the chemical, physicochemical, and biological properties of PVC sheets treated with UV irradiation on their surfaces to suppress the elution of a plasticizer, di-(2-ethylhexyl) phthalate (DEHP), for developing novel polyvinyl chloride (PVC) medical devices. The PVC sheets irradiated under conditions 1 (52.5 μW/cm(2), 136 J/cm(2)) and 2 (0.45 mW/cm(2), 972 J/cm(2)) exhibited considerable toxicity in cytotoxicity tests and chromosome aberration tests due to the generation of DEHP oxidants, but no toxicity was detected in the PVC sheet irradiated under condition 3 (8.3 mW/cm(2), 134 J/cm(2)). The release of DEHP from the surface irradiated under condition 3 was significantly suppressed, and mono-(2-ethylhexyl) phthalate (MEHP) converted from a portion of DEHP could be easily removed from the surface by washing with methanol. The physicochemical properties of the surface regarding the suppression of DEHP elution remained stable through all sterilizations tested, but MEHP elution was partially recrudesced by the sterilizations except for gamma irradiation. These results indicated that UV irradiation using a strong UV-source over a short time (condition 3) followed by methanol washing and gamma sterilization may be useful for preparing novel PVC products that did not elute plasticizers and do not exhibit toxicity originating from UV irradiation.

  8. UV-induced mutagenesis of oxidation activity of ferrous ion of Thiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An excellent strain named T. f6 was isolated and screened, the dose and other condition for the UV-induced mutagenesis were studied and the richened positive mutant m+ T. f6 was applied in the column leaching of copper-contain ing sulfides. The results show that T. f6 is characterized by rapid oxidation of ferrous ion and cupric sulfide, high tolerance of toxic ion and short generation time. The best mutagenic effectiveness can be obtained under the dose of low kill rate of UV and low temperature treatment, under which the best richened m+ T. f6 can be shortened 1.4h. It was shown by the column leaching of copper that the leaching rate can be enhanced by at least 11% compared with the original one by the mutants.

  9. UV-VIS spectroscopic study of one pot synthesized strontium oxide quantum dots

    Science.gov (United States)

    Nemade, K. R.; Waghuley, S. A.

    The properties of drastically change when matter makes transition from 1D, 2D, 3D, to 0D. The quantum dots (QDs) of strontium oxide (SrO) were synthesized by one pot chemical precipitation method using hexamethylenetetramine (HMT). The radius of SrO QDs was calculated from hyperbolic band model (HBM). The direct and indirect band gaps of SrO QDs were estimated from UV-VIS analysis. The particle size was found to be 2.48 nm. The quantum confinement effect in SrO QDs is discussed through exciton Bohr radius. The particle size from UV-VIS analysis is in excellent agreement with fluorescence and TEM.

  10. Effects of UV-C and Vacuum-UV TiO2 Advanced Oxidation Processes on the Acute Mortality of Microalgae.

    Science.gov (United States)

    McGivney, Eric; Carlsson, Magnus; Gustafsson, Jon Petter; Gorokhova, Elena

    2015-01-01

    Advanced oxidation processes/technologies (AOT) that combine a semiconductor, such as titanium dioxide (TiO2 ), with a UV source have been used to eliminate microorganisms in various water treatment applications. To facilitate the applicability of this technique, the gain in efficiency from the semiconductor compared to the UV source alone with respect to different target organisms requires evaluation. The primary objective of this study was to determine the effects of TiO2 and UV wavelength on a freshwater alga, Pseudokirchneriella subcapitata and a marine alga, Tetraselmis suecica. For each species, dose-response experiments were conducted to determine the median lethal dose (LC50 ) of the following treatments: UV light emitted with a peak of 254 nm, UV light emitted with a peak of 254 nm in the presence of TiO2 and UV light emitted with a peak of 254 and 185 nm in the presence of TiO2 . In both species, the presence of TiO2 significantly increased mortality. Across all three treatments, P. subcapitata was more sensitive than T. suecica; moreover, the addition of the 185 nm wavelength significantly increased cell mortality in P. subcapitata but not in T. suecica.

  11. Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Xiang, Yingying; Fang, Jingyun; Shang, Chii

    2016-03-01

    The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed.

  12. Studies on polymer-coated zinc oxide nanoparticles: UV-blocking efficacy and in vivo toxicity.

    Science.gov (United States)

    Girigoswami, Koyeli; Viswanathan, Meenakshi; Murugesan, Ramachandran; Girigoswami, Agnishwar

    2015-11-01

    Zinc oxide (ZnO) is explicitly used in sunscreens and cosmetic products; however, its effect in vivo is toxic in some cases. The UV blocking efficacy of ZnO nanoparticles is lost due to photocatalysis. To isolate a lower toxic species of sunblockers, ZnO nanoparticles were synthesized and coated with chitosan - a natural polymer (ZnO-CTS) and polyethylene glycol (PEG) - a synthetic polymer (ZnO-PEG). Coating with CTS and PEG circumvented the photocatalytic activity, increased the stability and improved the UV absorption efficacy. The effect of ZnO, ZnO-CTS and ZnO-PEG nanoparticles in vivo on zebrafish embryo revealed lower deposition of ZnO-CTS and ZnO-PEG nanoparticles atop the eggs compared to ZnO. The survival of zebrafish embryos was always found to be higher in case of ZnO-CTS with respect to ZnO-treated ones. PEG coating exhibited better UV attenuation, but, in vivo it induced delayed hatching. Thus, one of the reasons for better survival could be attributed to lower aggregation of ZnO-CTS nanoparticles atop eggs thereby facilitating the breathing of embryos.

  13. Fate of citalopram during water treatment with O3, ClO2, UV and fenton oxidation

    DEFF Research Database (Denmark)

    Hörsing, Maritha; Kosjek, Tina; Andersen, Henrik Rasmus;

    2012-01-01

    In the present study we investigate the fate of citalopram (CIT) at neutral pH using advanced water treatment technologies that include O3, ClO2 oxidation, UV irradiation and Fenton oxidation. The ozonation resulted in 80% reduction after 30 min treatment. Oxidation with ClO2 removed >90% CIT...... at a dosage of 0.1 mg L−1. During UV irradiation 85% reduction was achieved after 5 min, while Fenton with addition of 14 mg L−1 (Fe2+) resulted in 90% reduction of CIT. During these treatment experiments transformation products (TPs) were formed from CIT, where five compounds were identified by using high...

  14. Degradation of carbamazepine by UV/chlorine advanced oxidation process and formation of disinfection by-products.

    Science.gov (United States)

    Zhou, Shiqing; Xia, Ying; Li, Ting; Yao, Tian; Shi, Zhou; Zhu, Shumin; Gao, Naiyun

    2016-08-01

    Pharmaceuticals in water are commonly found and are not efficiently removed by current treatment processes. Degradation of antiepileptic drug carbamazepine (CBZ) by UV/chlorine advanced oxidation process was systematically investigated in this study. The results showed that the UV/chlorine process was more effective at degrading CBZ than either UV or chlorination alone. The CBZ degradation followed pseudo-first order reaction kinetics, and the degradation rate constants (kobs) were affected by the chlorine dose, solution pH, and natural organic matter concentration to different degrees. Degradation of CBZ greatly increased with increasing chlorine dose and decreasing solution pH during the UV/chlorine process. Additionally, the presence of natural organic matter in the solution inhibited the degradation of CBZ. UV photolysis, chlorination, and reactive species (hydroxyl radical •OH and chlorine atoms •Cl) were identified as responsible for CBZ degradation in the UV/chlorine process. Finally, a degradation pathway for CBZ in the UV/chlorine process was proposed and the formation potentials of carbonaceous and nitrogenous disinfection by-products were evaluated. Enhanced formation of trichloroacetic acid, dichloroacetonitrile, and trichloronitromethane precursors should be considered when applying UV/chlorine advanced oxidation process to drinking water.

  15. Transition metal-modified zinc oxides for UV and visible light photocatalysis.

    Science.gov (United States)

    Bloh, J Z; Dillert, R; Bahnemann, D W

    2012-11-01

    In order to use photocatalysis with solar light, finding more active and especially visible light active photocatalysts is a very important challenge. Also, studies of these photocatalysts should employ a standardized test procedure so that their results can be accurately compared and evaluated with one another. A systematic study of transition metal-modified zinc oxide was conducted to determine whether they are suitable as visible light photocatalysts. The photocatalytic activity of ZnO modified with eight different transition metals (Cu, Co, Fe, Mn, Ni, Ru, Ti, Zr) in three different concentrations (0.01, 0.1, and 1 at.%) was investigated under irradiation with UV as well as with visible light. The employed activity test is the gas-phase degradation of acetaldehyde as described by the ISO standard 22197-2. The results suggest that the UV activity can be improved with almost any modification element and that there exists an optimal modification ratio at about 0.1 at.%. Additionally, Mn- and Ru-modified ZnO display visible light activity. Especially the Ru-modified ZnO is highly active and surpasses the visible light activity of all studied titania standards. These findings suggest that modified zinc oxides may be a viable alternative to titanium dioxide-based catalysts for visible light photocatalysis. Eventually, possible underlying mechanisms are proposed and discussed.

  16. Effect of matrix components on UV/H2O2 and UV/S2O8(2-) advanced oxidation processes for trace organic degradation in reverse osmosis brines from municipal wastewater reuse facilities.

    Science.gov (United States)

    Yang, Yi; Pignatello, Joseph J; Ma, Jun; Mitch, William A

    2016-02-01

    When reverse osmosis brines from potable wastewater reuse plants are discharged to poorly-flushed estuaries, the concentrated organic contaminants are a concern for receiving water ecosystems. UV/hydrogen peroxide (UV/H2O2) and UV/persulfate (UV/S2O8(2-)) advanced oxidation processes (AOPs) may reduce contaminant burdens prior to discharge, but the effects of the high levels of halide, carbonate and effluent organic matter (EfOM) normally present in these brines are unclear. On the one hand, these substances may reduce process efficiency by scavenging reactive oxygen species (ROS), hydroxyl (OH) and sulfate (SO4(-) radicals. On the other, the daughter radicals generated by halide and carbonate scavenging may themselves degrade organics, offsetting the effect of ROS scavenging. UV/H2O2 and UV/S2O8(2-) AOPs were compared for degradation of five pharmaceuticals spiked into brines obtained from two reuse facilities and the RO influent from one of them. For UV/H2O2, EfOM scavenged ∼75% of the OH, reducing the degradation efficiency of the target contaminants to a similar extent; halide and carbonate scavenging and the reactivities of associated daughter radicals were less important. For UV/S2O8(2-), anions (mostly Cl(-)) scavenged ∼93% of the SO4(-). Because daughter radicals of Cl(-) contributed to contaminant degradation, the reduction in contaminant degradation efficiency was only ∼75-80%, with the reduction driven by daughter radical scavenging by EfOM. Conversion of SO4(-) to more selective halogen and carbonate radicals resulted in a wider range of degradation efficiencies among the contaminants. For both AOPs, 250 mJ/cm(2) average fluence achieved significant removal of four pharmaceuticals, with significantly better performance by UV/S2O8(2-) treatment for some constituents. Accounting for the lower brine flowrates, the energy output to achieve this fluence in brines is comparable to that often applied to RO permeates. However, much higher fluence was

  17. Combining activated carbon adsorption with heterogeneous photocatalytic oxidation: lack of synergy for biologically treated greywater and tetraethylene glycol dimethyl ether.

    Science.gov (United States)

    Gulyas, Holger; Argáez, Angel Santiago Oria; Kong, Fanzhuo; Jorge, Carlos Liriano; Eggers, Susanne; Otterpohl, Ralf

    2013-01-01

    The aim of the study was to evaluate whether the addition of activated carbon in the photocatalytic oxidation of biologically pretreated greywater and of a polar aliphatic compound gives synergy, as previously demonstrated with phenol. Photocatalytic oxidation kinetics were recorded with fivefold concentrated biologically pretreated greywater and with aqueous tetraethylene glycol dimethyl ether solutions using a UV lamp and the photocatalyst TiO2 P25 in the presence and the absence of powdered activated carbon. The synergy factor, SF, was quantified as the ratio of photocatalytic oxidation rate constant in the presence of powdered activated carbon to the rate constant without activated carbon. No synergy was observed for the greywater concentrate (SF approximately 1). For the aliphatic compound, tetraethylene glycol dimethyl ether, addition of activated carbon actually had an inhibiting effect on photocatalysis (SF photocatalytic oxidation of tetraethylene glycol dimethyl ether by addition of powdered activated carbon was attributed to shading of the photocatalyst by the activated carbon particles. It was assumed that synergy in the hybrid process was limited to aromatic organics. Regardless of the lack of synergy in the case of biologically pretreated greywater, the addition of powdered activated carbon is advantageous since, due to additional adsorptive removal of organics, photocatalytic oxidation resulted in a 60% lower organic concentration when activated carbon was present after the same UV irradiation time.

  18. Photocatalytic degradation of phenol by iodine doped tin oxide nanoparticles under UV and sunlight irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hamdi, Abdullah M.; Sillanpää, Mika [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Dutta, Joydeep, E-mail: dutta@squ.edu.om [Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 17, 123 Al-Khoudh (Oman)

    2015-01-05

    Highlights: • A sol–gel method used to synthesize tin oxide nanoparticles. • Nanoparticles of tin oxide doped with different iodine concentrations. • Degradation studies carried up with UV–vis, TOC, HPLC and GC instruments. • 1% iodine doped tin dioxide showed maximum photodegradation efficiency. - Abstract: Iodine doped tin oxide (SnO{sub 2}:I) nanoparticles were prepared by sol–gel synthesis and their photocatalytic activities with phenol as a test contaminant were studied. In the presence of the catalysts, phenol degradation under direct sunlight was comparable to what was achieved under laboratory conditions. Photocatalytic oxidation reactions were studied by varying the catalyst loading, light intensity, illumination time, pH of the reactant and phenol concentration. Upon UV irradiation in the presence of SnO{sub 2}:I nanoparticles, phenol degrades very rapidly within 30 min, forming carboxylic acid which turns the solution acidic. Phenol degradation rate with 1% iodine doped SnO{sub 2} nanoparticles is at least an order of magnitude higher compared to the degradation achieved through undoped SnO{sub 2} nanoparticles under similar illumination conditions.

  19. The synthesis, characterization and biological evaluation of a new nitric oxide donor agent

    Directory of Open Access Journals (Sweden)

    Profire Lenuta

    2014-01-01

    Full Text Available The synthesis of a new xanthine nitric oxide donor (TSP-81 has been discussed. The designed compound includes two structural moieties - theophylline (1,3-dimethylxanthine and acetaminophen (4-hydroxyacetanilide linked by the nitric oxide donor alkyl chain as a spacer. The compound has been characterized by microanalysis (CHN, 1H-NMR, 13C-NMR, FT-IR, UV-vis, TG and DTG. The thermal behaviour showed that TSP-81 melts with decomposition, in four steps, the most important ones being the 2nd one (the registered weight loss being 17.6 % and the 3rd one (with a registered weight loss of 30.4 %. The toxicity degree, the anti-inflammatory effect and the ability of releasing nitric oxide of the TSP-81 have also been evaluated. The biological assays established that TSP-81 exhibits enhanced biological properties such as lower toxicity and higher anti-inflammatory effect in reference with theophylline and acetaminophen, the drugs used as parents molecules. The TSP-81 is approximately 2 times more active than theophylline and 4 times more active than acetaminophen in reducing cotton pellet-granuloma formation. Furthermore, the release of nitric oxide (NO appears to have an important contribution to enhancing the anti-inflammatory effect.

  20. Effects of Oxidative Stress on Mesenchymal Stem Cell Biology

    Science.gov (United States)

    2016-01-01

    Mesenchymal stromal/stem cells (MSCs) are multipotent stem cells present in most fetal and adult tissues. Ex vivo culture-expanded MSCs are being investigated for tissue repair and immune modulation, but their full clinical potential is far from realization. Here we review the role of oxidative stress in MSC biology, as their longevity and functions are affected by oxidative stress. In general, increased reactive oxygen species (ROS) inhibit MSC proliferation, increase senescence, enhance adipogenic but reduce osteogenic differentiation, and inhibit MSC immunomodulation. Furthermore, aging, senescence, and oxidative stress reduce their ex vivo expansion, which is critical for their clinical applications. Modulation of sirtuin expression and activity may represent a method to reduce oxidative stress in MSCs. These findings have important implications in the clinical utility of MSCs for degenerative and immunological based conditions. Further study of oxidative stress in MSCs is imperative in order to enhance MSC ex vivo expansion and in vivo engraftment, function, and longevity. PMID:27413419

  1. Disinfection of biologically treated wastewater and prevention of biofouling by UV/electrolysis hybrid technology: influence factors and limits for domestic wastewater reuse.

    Science.gov (United States)

    Haaken, Daniela; Dittmar, Thomas; Schmalz, Viktor; Worch, Eckhard

    2014-04-01

    Reuse of wastewater contributes significantly to an efficient and sustainable water usage. However, due to the presence of a multitude of pathogens (e.g. bacteria, viruses, worms, protozoa) in secondary effluents, disinfection procedures are indispensable. In decentralized wastewater treatment, UV irradiation represents one of the most common disinfection methods in addition to membrane processes and to a certain extent electrochemical procedures. However, the usage of UV disinfected secondary effluents for domestic (sanitary) or irrigation purposes bears a potential health risk due to the possible photo and dark repair of reversibly damaged bacteria. Against this background, the application of the UV/electrolysis hybrid technology for disinfection and prevention of bacterial reactivation in biologically treated wastewater was investigated in view of relevant influence factors and operating limits. Furthermore, the influence of electrochemically generated total oxidants on the formation of biofilms on quartz glass surfaces was examined, since its preventive avoidance contributes to an enhanced operational safety of the hybrid reactor. It was found that reactivation of bacteria in UV irradiated, biologically treated wastewater can be prevented by electrochemically produced total oxidants. In this regard, the influence of the initial concentration of the microbiological indicator organism Escherichia coli (E. coli) (9.3*10(2)-2.2*10(5) per 100 mL) and the influence of total suspended solids (TSS) in the range of 11-75 mg L(-1) was examined. The concentration of total oxidants necessary for prevention of bacterial regrowth increases linearly with the initial E. coli and TSS concentration. At an initial concentration of 933 E. coli per 100 mL, a total oxidants concentration of 0.4 mg L(-1) is necessary to avoid photo reactivation (at 4200 Lux), whereas 0.67 mg L(-1) is required if the E. coli concentration is enhanced by 2.4 log levels (cTSS = constant = 13 mg

  2. Oxidative metabolites of lycopene and their biological functions

    Science.gov (United States)

    To gain a better understanding of the beneficial biological activities of lycopene on cancer prevention, a greater knowledge of the metabolism of lycopene is needed. In particular, the identification of lycopene metabolites and oxidation products in vivo; the importance of tissue specific lycopene c...

  3. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian; N. Mikkelsen, Teis; Ro-Poulsen, Helge

    Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high...

  4. Effects of inorganics on the degradation of micropollutants with vacuum UV (VUV) advanced oxidation.

    Science.gov (United States)

    Duca, Clara; Imoberdorf, Gustavo; Mohseni, Madjid

    2017-02-21

    This research focused on the effects of inorganic water constituents on the efficiency of vacuum UV (VUV) for the degradation of micropollutants in surface water supplies. Atrazine was used as a model miropollutant, and bicarbonate, sulphate, and nitrate were used as the most common inorganic constituents in the water matrix. First, the absorbance of radiation at 254 and 185 nm was measured in the presence of different ions. At 254 nm, only nitrate showed a measurable absorption coefficient of [Formula: see text] = 3.51 M[Formula: see text] cm[Formula: see text], and all other ions showed a molar absorption coefficient below the detection limit. However, at 185 nm, all the ions showed high absorption coefficients, with nitrate giving the highest absorption coefficient of [Formula: see text] = 5568 M[Formula: see text] cm[Formula: see text]. Second, the hydroxyl radical (HO[Formula: see text]) scavenging effects of the same inorganic ions were evaluated; nitrate and bicarbonate showed a negative effect during the UV/H2O2 and VUV advanced oxidation processes. Sulfate was photolyzed with 185 nm UV to form HO[Formula: see text], and for this reason, it assisted the degradation of the target micropollutant, as demonstrated by increases in the degradation rate constant. An additional component of this work involved developing a method for measuring the quantum yield of atrazine at 185 nm. This made it possible to distinguish the contribution of OH radical attach from that of direct photolysis towards the degradation of atrazine.

  5. Elimination of pharmaceutical residues in biologically pre-treated hospital wastewater using advanced UV irradiation technology: A comparative assessment

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, C., E-mail: christian.koehler@tudor.lu [Public Research Centre Henri Tudor/Resource Centre for Environmental Technologies, 66 rue de Luxembourg, BP 144, L-4002 Esch-sur-Alzette (Luxembourg); Venditti, S.; Igos, E.; Klepiszewski, K.; Benetto, E.; Cornelissen, A. [Public Research Centre Henri Tudor/Resource Centre for Environmental Technologies, 66 rue de Luxembourg, BP 144, L-4002 Esch-sur-Alzette (Luxembourg)

    2012-11-15

    UV irradiation technology as a membrane bioreactor (MBR) post-treatment was investigated and assessed. Both UV low pressure (LP) and medium pressure (MP) lamps were examined. The technology was installed in a pilot plant treating hospital wastewater to provide the study with adequate field data. The effect of the UV irradiation was enhanced with varying dosages of H{sub 2}O{sub 2} to establish an advanced oxidation process (AOP). The efficiency of the pharmaceutical removal process was assessed by examining 14 micropollutants (antibiotics, analgesics, anticonvulsants, beta-blockers, cytostatics and X-ray contrast media) which are typically released by hospitals and detected with liquid chromatography coupled tandem mass spectrometry (LC-MS/MS). While the MBR treatment generally showed only a low degradation capacity for persistent pharmaceuticals, much better degradation was obtained by applying UV irradiation and H{sub 2}O{sub 2} as AOP. The 'conventional' cost-benefit analysis of the different technology options taking into account both electrical energy consumption and pharmaceutical removal efficiency, revealed clearly better performance of low pressure UV lamps as AOP. However, a holistic comparison between the different scenarios was carried out by evaluating their environmental impacts using the life cycle assessment (LCA) methodology. Decisive advantages were highlighted to include this approach in the decision making process.

  6. Comparison of degradation reactions of Acid Yellow 61 in both oxidation processes of H202/UV and 03

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H2 O2/UV and O3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H2O2/UV has beneficial effect on mineralization than O3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.

  7. Decolourisation of simulated reactive dyebath effluents by electrochemical oxidation assisted by UV light.

    Science.gov (United States)

    López-Grimau, V; Gutiérrez, M C

    2006-01-01

    This study is focused on the optimisation of the electrochemical decolourisation of textile effluents containing reactive dyes with the aim of making feasible-technically and economically-this method at industrial scale. Coloured waters were treated in continuous at low current density, to reduce the electrical consumption. Ti/PtO(x) electrodes were used to oxidize simulated dyebaths prepared with an azo/dichlorotriazine reactive dye (C.I. Reactive Orange 4). The decolourisation yield was dependent on the dyeing electrolyte (NaCl or Na(2)SO(4)). Dyeing effluents which contained from 0.5 to 20 gl(-1) of NaCl reached a high decolourisation yield, depending on the current density, immediately after the electrochemical process. These results were improved when the effluents were stored for several hours under solar light. After the electrochemical treatment the effluents were stored in a tank and exposed under different lighting conditions: UV light, solar light and darkness. The evolution of the decolourisation versus the time of storage was reported and kinetic constants were calculated. The time of storage was significantly reduced by the application of UV light. A dye mineralization study was also carried out on a concentrated dyebath. A TOC removal of 81% was obtained when high current density was applied for a prolonged treatment with recirculation. This treatment required a high electrical consumption.

  8. UV spectra and OH-oxidation kinetics of gaseous phase morpholinic compounds

    KAUST Repository

    Al Rashidi, M.

    2014-05-01

    This paper presents an experimental study of the UV spectra as well as the kinetics of gaseous phase OH-oxidation of morpholine, N-formylmorpholine (NFM) and N-acetlymorpholine (NAM). The spectra recorded using a UV spectrometer in the spectral range 200-280nm show that the analytes mainly absorb at wavelengths less than 280nm. This indicates that their photolysis potential in the troposphere is insignificant. Meanwhile, the OH-reactivity of these analytes was studied using a triple-jacket 2m long reactor equipped with a multi-reflection system and coupled to an FTIR spectrometer. The experiments were carried out at 295 and 313K for the amine and amides, respectively. The study was conducted in the relative mode using isoprene and benzaldehyde as reference compounds. The rate constants obtained are 14.0±1.9, 4.0±1.1 and 3.8±1.0 (in units of 10-11cm3molecule-1s-1) for morpholine, NFM and NAM respectively. These results are discussed in terms of reactivity and compared to those obtained for other oxy-nitrogenated species. In addition, the determined rate constants are used to estimate effective atmospheric lifetimes of the investigated morpholinic compounds with respect to reaction with OH radicals. © 2014 Elsevier Ltd.

  9. Enhanced electrochemical oxidation of phenol by introducing ferric ions and UV radiation

    Institute of Scientific and Technical Information of China (English)

    MAO Xuhui; WEI Lin; HONG Song; ZHU Hua; LIN An; GAN Fuxing

    2008-01-01

    The mineralization of phenol in aerated electrochemical oxidation has been investigated. The results show that a cathodic Fenton process can occur when the Ti-0.3Mo-0.8Ni alloy material is used as cathode in solution containing ferric or ferrous ions; moreover,the reinforcement of cathodic Fenton process on the total organic carbon (TOC) removal rate of phenol is quite distinct. Among the metallic ions investigated, the ferric ion is the best catalyst for the electrochemical mineralization of phenol at initial pH 2.0, and the optimal concentration range is from 50 to 200 mg/L. The favorable pH range and supporting electrolyte (Na2SO4) concentration for mineralization of phenol in solution containing ferrous ions are 1.8-2.3 and below 0.10 mol/L, respectively. UV radiation can improve the TOC removal rate of phenol, but the enhanced effect varies in different solutions. In the solution containing ferric ions, an equal sum or synergetic effect can be observed. The optimal effect of electrolysis system under UV radiation is achieved in the solution containing 50 mg/L Fe3+ with a final removal percentage of 81.3%.

  10. UV spectra and OH-oxidation kinetics of gaseous phase morpholinic compounds

    Science.gov (United States)

    Al Rashidi, M.; El Masri, A.; Roth, E.; Chakir, A.

    2014-05-01

    This paper presents an experimental study of the UV spectra as well as the kinetics of gaseous phase OH-oxidation of morpholine, N-formylmorpholine (NFM) and N-acetlymorpholine (NAM). The spectra recorded using a UV spectrometer in the spectral range 200-280 nm show that the analytes mainly absorb at wavelengths less than 280 nm. This indicates that their photolysis potential in the troposphere is insignificant. Meanwhile, the OH-reactivity of these analytes was studied using a triple-jacket 2 m long reactor equipped with a multi-reflection system and coupled to an FTIR spectrometer. The experiments were carried out at 295 and 313 K for the amine and amides, respectively. The study was conducted in the relative mode using isoprene and benzaldehyde as reference compounds. The rate constants obtained are 14.0 ± 1.9, 4.0 ± 1.1 and 3.8 ± 1.0 (in units of 10-11 cm3 molecule-1 s-1) for morpholine, NFM and NAM respectively. These results are discussed in terms of reactivity and compared to those obtained for other oxy-nitrogenated species. In addition, the determined rate constants are used to estimate effective atmospheric lifetimes of the investigated morpholinic compounds with respect to reaction with OH radicals.

  11. Oxygen Isotope Signatures of UV Oxidation of Phosphite: Implications for a Biomarker in the Search for Life

    Science.gov (United States)

    Chang, S.; Blake, R.

    2013-12-01

    On the present Earth, phosphorus (P) occurs primarily in fully-oxidized form (P5+) as orthophosphate (PO4), and PO4 derived from igneous apatite minerals is considered as the primary source of P for prebiotic reactions and evolution of first life. Recent discoveries have shown, however, that abundant P compounds with valence aqueous weathering of phosphides in meteorites(1) and of fulgurites formed by lightning strikes or high-energy impacts(2). These studies concluded that PO3 was likely abundant on the oxygen-free early Earth and extraterrestrial environments, and was possibly the first form of biologically-available P, due to its greater solubility and reactivity relative to PO4 and apatite(1). These findings suggest alternative prebiotic P reservoirs to igneous apatite that would also likely have very different prebiotic/baseline PO4 δ18O values. Here we report results of experimental studies to determine the O-isotope signature of PO4 derived from PO3 oxidation catalyzed by ultraviolet (UV) radiation, which was not blocked on early Earth due to lack of an ozone layer(3). These studies are critical for interpretation of PO4 δ18O biosignatures preserved in ancient terrestrial and extraterrestrial samples. Experiments on UV-catalyzed oxidation of aqueous PO3 to PO4 were conducted using δ18O-labled PO3 and different δ18O-labled waters to gain information on (i) the source(s) of O involved and mechanism of oxidation of PO3 to PO4, and (ii) fractionations accompanying O incorporation into product PO4. Our preliminary results under modern atmospheric conditions indicate incorporation of ca. 15 % O from ambient water and ca. 10 % atmospheric O (δ18O: ~23.5 ‰) into product PO4 with a fractionation between incorporated water O and ambient water O of -20 × 4 ‰ (1 SD), assuming 75 % inheritance of O from PO3 and direct incorporation of atmospheric O into product PO4 without fractionation. If initial δ18O values of PO3 sources were the same as igneous apatite (6

  12. Several Rules for Treating Phenol Wastewater via Oxidation by O3/UV-formed Radicals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The treatment of phenol wastewater with an ultraviolet source and an oxone generator by introducing salicylic acid as the capturer is described. The presence of HO·during the phenol degradation has been proved. The impacts of factors such as acidity and reaction time on the HO· formation are also discussed. The results demonstrate that HO· generated from ozone/UV oxidation under a basic condition is the immediate cause of phenol degradation. At room temperature and a pH value of 9.93, the degradation of phenol occurs rapidly within 0.5 min and the removal of phenol(100 mg/L) is above 98.5% within 15 min; in the meantime, the pH value declines gradually with the degradation of phenol. A discussion about the formation and the transformation of the intermediate products during phenol degradation is included.

  13. Fenton Process Coupled to Ultrasound and UV Light Irradiation for the Oxidation of a Model Pollutant

    Directory of Open Access Journals (Sweden)

    Karen E. Barrera-Salgado

    2016-01-01

    Full Text Available The Fenton process coupled to photosonolysis (UV light and Us, using Fe2O3 catalyst supported on Al2O3, was used to oxidize a model pollutant like acid green 50 textile dye (AG50. Dye degradation was followed by AG50 concentration decay analyses. It was observed that parameters like iron content on a fixed amount of catalyst supporting material, catalyst annealing temperature, initial dye concentration, and the solution pH influence the overall treatment efficiency. High removal efficiencies of the model pollutant are achieved. The stability and reusability tests of the Fe2O3 catalyst show that the catalyst can be used up to three cycles achieving high discoloration. Thus, this catalyst is highly efficient for the degradation of AG50 in the Fenton process.

  14. Dispersion and surface functionalization of oxide nanoparticles for transparent photocatalytic and UV-protecting coatings and sunscreens

    Directory of Open Access Journals (Sweden)

    Bertrand Faure, German Salazar-Alvarez, Anwar Ahniyaz, Irune Villaluenga, Gemma Berriozabal, Yolanda R De Miguel and Lennart Bergström

    2013-01-01

    Full Text Available This review describes recent efforts on the synthesis, dispersion and surface functionalization of the three dominating oxide nanoparticles used for photocatalytic, UV-blocking and sunscreen applications: titania, zinc oxide, and ceria. The gas phase and liquid phase synthesis is described briefly and examples are given of how weakly aggregated photocatalytic or UV-absorbing oxide nanoparticles with different composition, morphology and size can be generated. The principles of deagglomeration are reviewed and the specific challenges for nanoparticles highlighted. The stabilization of oxide nanoparticles in both aqueous and non-aqueous media requires a good understanding of the magnitude of the interparticle forces and the surface chemistry of the materials. Quantitative estimates of the Hamaker constants in various media and measurements of the isoelectric points for the different oxide nanoparticles are presented together with an overview of different additives used to prepare stable dispersions. The structural and chemical requirements and the various routes to produce transparent photocatalytic and nanoparticle-based UV-protecting coatings, and UV-blocking sunscreens are described and discussed.

  15. Synthesis of ALD zinc oxide and thin film materials optimization for UV photodetector applications

    Science.gov (United States)

    Tapily, Kandabara Nouhoum

    Zinc oxide (ZnO) is a direct, wide bandgap semiconductor material. It is thermodynamically stable in the wurtzite structure at ambient temperature conditions. ZnO has very interesting optical and electrical properties and is a suitable candidate for numerous optoelectronic applications such as solar cells, LEDs and UV-photodetectors. ZnO is a naturally n-type semiconductor. Due to the lack of reproducible p-type ZnO, achieving good homojunction ZnO-based photodiodes such as UV-photodetectors remains a challenge. Meanwhile, heterojunction structures of ZnO with p-type substrates such as SiC, GaN, NiO, AlGaN, Si etc. are used; however, those heterojunction diodes suffer from low efficiencies. ZnO is an n-type material with numerous intrinsic defect levels responsible for the electrical and optical behaviors. Presently, there is no clear consensus about the origin of those defects. In this work, ZnO was synthesized by atomic layer deposition (ALD). ALD is a novel deposition technique suitable for nanotechnology engineering that provides unique features such as precise control of ZnO thin film with atomic resolution, high uniformity, good conformity and high aspect ratio. Using this novel deposition technique, the ALD ZnO deposition process was developed and optimized using diethyl zinc as the precursor for zinc and water vapor as the oxygen source. In order to optimize the film quality for use in electronic applications, the physical, mechanical and electrical properties were investigated. The structural and mechanical properties of the ALD ZnO thin films were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), spectroscopic Ellipsometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-VIS absorption and nanoindentation. The electrical characterizations were performed using C-V, I-V, DLTS, Hall Effect, and four-point probe. The intrinsic defects responsible

  16. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian; N. Mikkelsen, Teis; Ro-Poulsen, Helge

    -B was demonstrated to decrease photosynthesis and shift carbon allocation from shoots to roots. Moreover, ambient UV-B increased plant stress with detrimental effects on electron processing in the photosynthetic apparatus. Plant responses did not lead to clear changes in the amount of fungal root symbionts...... on high-arctic vegetation. They supplement previous investigations from the Arctic focussing on other variables like growth etc., which have reported no or minor plant responses to UV-B, and clearly indicates that UV-B radiation is an important factor affecting plant life at high-arctic Zackenberg...

  17. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian; N. Mikkelsen, Teis; Ro-Poulsen, Helge

    (mycorrhiza) or in the biomass of microbes in the soil of the root zone. However, the composition of the soil microbial community was different in the soils under ambient and reduced UV radiation after three treatment years. These results provide new insight into the negative impact of current UV-B fluxes......-B was demonstrated to decrease photosynthesis and shift carbon allocation from shoots to roots. Moreover, ambient UV-B increased plant stress with detrimental effects on electron processing in the photosynthetic apparatus. Plant responses did not lead to clear changes in the amount of fungal root symbionts...

  18. UV/H2O2,UV/O3,UV/H2O2/O3催化处理城市固体垃圾填埋渗出物%UV-Catalytic Treatment of Municipal Solid-Waste Landfill Leachate with Hydrogen Peroxide and Ozone Oxidation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The performance of UV/H2O2, UV/O3, and UV/H2O2/O3 oxidation systems for the treatment of municipal solid-waste landfill leachate was investigated. Main objective of the experiment was to remove total organic carbon (TOC), non-biodegradable organic compounds (NBDOC) and color. In UV/H2O2 oxidation experiment,with the increase of H2O2 dosage, removal efficiencies of TOC and color along with the ratio of biochemical oxygen demand (BOD) to chemical oxygen demand (COD) of the effluent were increased and a better performance was obtained than the system H2O2 alone. In UV/H2O2 oxidation, under the optimum condition H2O2 (0.2 time),removal efficiencies of TOC and color were 78.9% and 95.5%, respectively, and BOD/COD ratio was significantly increased from 0.112 to 0.366. In UV/O3 oxidation, with the increase of O3 dosage, removal efficiencies of TOC and color along with BOD/COD ratio of the effluent were increased and a better performance was obtained than the system O3 alone. Under the optimum condition UV/O3 (50 mg.min-1), removal efficiencies of TOC and color were 61.0% and 87.2%, respectively, and BOD/COD ratio was significantly increased from 0.112 to 0.323. In UV/H2O2/O3 system, color removal and BOD/COD ratio were improved further and TOC removal efficiency was found to be 30.4% higher than the system UV/O3 without H2O2.

  19. Photoinitiated oxidation of geosmin and 2-methylisoborneol by irradiation with 254 nm and 185 nm UV light.

    Science.gov (United States)

    Kutschera, Kristin; Börnick, Hilmar; Worch, Eckhard

    2009-05-01

    The degradation of geosmin and 2-methylisoborneol (2-MIB) by UV irradiation at different wavelengths was investigated under varying boundary conditions. The results showed that conventional UV radiation (254 nm) is ineffective in removing these compounds from water. In contrast to the usual UV radiation UV/VUV radiation (254+185 nm) was more effective in the removal of the taste and odour compounds. The degradation could be described by a simple pseudo first-order rate law with rate constants of about 1.2 x 10(-3) m(2)J(-1) for geosmin and 2-MIB in ultrapure water. In natural water used for drinking water abstraction the rate constants decreased to 2.7 x 10(-4) m(2)J(-1) for geosmin and 2.5 x 10(-4) m(2)J(-1) for 2-MIB due to the presence of NOM. Additionally, the formation of the by-product nitrite was studied. In the UV/VUV irradiation process up to 0.6 mg L(-1) nitrite was formed during the complete photoinitiated oxidation of the odour compounds. However, the addition of low ozone doses could prevent the formation of nitrite in the UV/VUV irradiation experiments.

  20. Durable antibacterial and UV protections of in situ synthesized zinc oxide nanoparticles onto cotton fabrics.

    Science.gov (United States)

    Shaheen, Th I; El-Naggar, Mehrez E; Abdelgawad, Abdelrahman M; Hebeish, A

    2016-02-01

    Herein we represent a new discovery based on amine material called hexamethyltriethylene tetramine (HMTETA). We have observed that when an aqueous solution of Zn(NO3)·6H2O was added to aqueous solution of HMTETA followed by shaking for a time, the colorless solution was converted to milky color under the alkaline medium provided by HMTETA prior to formation of uniform zinc oxide nanoparticles (ZnO NPs). The latter are in situ formed within the cotton fabrics without the support of capping or other stabilizing agents. Obviously, then, the new made of formation of ZnO NPs speaks of a single-stage process where cotton fabric is immersed in a prepared solution of the new precursors through which binding of ZnO NPs into the textile fabrics takes place. Textile fabrics are, indeed, used as a template, which is capable of maintaining the size and surface distribution of the as-synthesized nanoparticles in a uniform domain. It is also likely that nanoparticles is confined inside the fibril and microfibrils of the cotton fibers. World-class facilities have been employed to follow up the synthesis of ZnO NPs, their characterization and their application to confer, in particular, high durable antibacterial and UV protective function on cotton fabrics.

  1. On-line sensor monitoring for chemical contaminant attenuation during UV/H2O2 advanced oxidation process.

    Science.gov (United States)

    Yu, Hye-Weon; Anumol, Tarun; Park, Minkyu; Pepper, Ian; Scheideler, Jens; Snyder, Shane A

    2015-09-15

    A combination of surrogate parameters and indicator compounds were measured to predict the removal efficiency of trace organic compounds (TOrCs) using low pressure (LP)-UV/H2O2 advanced oxidation process (AOP), engaged with online sensor-based monitoring system. Thirty-nine TOrCs were evaluated in two distinct secondary wastewater effluents in terms of estimated photochemical reactivity, as a function of the rate constants of UV direct photolysis (kUV) and hydroxyl radical (OH) oxidation (kOH). The selected eighteen TOrCs were classified into three groups that served as indicator compounds: Group 1 for photo-susceptible TOrCs but with minor degradation by OH oxidation (diclofenac, fluoxetine, iohexol, iopamidol, iopromide, simazine and sulfamethoxazole); Group 2 for TOrCs susceptible to both direct photolysis and OH oxidation (benzotriazole, diphenhydramine, ibuprofen, naproxen and sucralose); and Group 3 for photo-resistant TOrCs showing dominant degradation by OH oxidation (atenolol, carbamazepine, DEET, gemfibrozil, primidone and trimethoprim). The results indicate that TOC (optical-based measurement), UVA254 or UVT254 (UV absorbance or transmittance at 254 nm), and total fluorescence can all be used as suitable on-line organic surrogate parameters to predict the attenuation of TOrCs. Furthermore, the automated real-time monitoring via on-line surrogate sensors and equipped with the developed degradation profiles between sensor response and a group of TOrCs removal can provide a diagnostic tool for process control during advanced treatment of reclaimed waters.

  2. Giardia duodenalis: Number and Fluorescence Reduction Caused by the Advanced Oxidation Process (H2O2/UV)

    Science.gov (United States)

    Guimarães, José Roberto; Franco, Regina Maura Bueno; Guadagnini, Regiane Aparecida; dos Santos, Luciana Urbano

    2014-01-01

    This study evaluated the effect of peroxidation assisted by ultraviolet radiation (H2O2/UV), which is an advanced oxidation process (AOP), on Giardia duodenalis cysts. The cysts were inoculated in synthetic and surface water using a concentration of 12 g H2O2 L−1 and a UV dose (λ = 254 nm) of 5,480 mJcm−2. The aqueous solutions were concentrated using membrane filtration, and the organisms were observed using a direct immunofluorescence assay (IFA). The AOP was effective in reducing the number of G. duodenalis cysts in synthetic and surface water and was most effective in reducing the fluorescence of the cyst walls that were present in the surface water. The AOP showed a higher deleterious potential for G. duodenalis cysts than either peroxidation (H2O2) or photolysis (UV) processes alone. PMID:27379301

  3. The mechanism of cysteine detection in biological media by means of vanadium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, A. G. [Universidade Tecnologica Federal do Parana, Departamento Academico de Fisica (Brazil); Barison, A. [Universidade Federal do Parana, Departamento de Quimica (Brazil); Oliveira, V. S. [Universidade Federal do Parana, Departamento de Fisica (Brazil); Foti, L.; Krieger, M. A. [Fundacao Oswaldo Cruz, Instituto de Biologia Molecular do Parana (Brazil); Dhalia, R.; Viana, I. F. T. [Fundacao Oswaldo Cruz, Centro de Pesquisas Aggeu Magalhaes (Brazil); Schreiner, W. H., E-mail: wido@fisica.ufpr.br [Universidade Federal do Parana, Departamento de Fisica (Brazil)

    2012-09-15

    We report on the interaction of vanadate nanoparticles, produced using the laser ablation in liquids synthesis, with cysteine in biological molecules. Cysteine is a very important amino acid present in most proteins, but also because cysteine and the tripeptide glutathione are the main antioxidant molecules in our body system. Detailed UV-Vis absorption spectra and dynamic light scattering measurements were done to investigate the detection of cysteine in large biological molecules. The intervalence band of the optical absorption spectra shows capability for quantitative cysteine sensing in the {mu}M range in biological macromolecules. Tests included cytoplasmic repetitive antigen and flagellar repetitive antigen proteins of the Trypanosoma cruzi protozoa, as well as the capsid p24 proteins from Human Immunodeficiency Virus type 1 and type 2. Detailed NMR measurements for hydrogen, carbon, and vanadium nuclei show that cysteine in contact with the vanadate looses hydrogen of the sulphydryl side chain, while the vanadate is reduced. The subsequent detachment of two deprotonated molecules to form cystine and the slow return to the vanadate complete the oxidation-reduction cycle. Therefore, the vanadate acts as a charge exchanging catalyst on cysteine to form cystine. The NMR results also indicate that the nanoparticles are not formed by the common orthorhombic V{sub 2}O{sub 5} form.

  4. Biological Fenton's oxidation of pentachlorophenol by aquatic plants.

    Science.gov (United States)

    Reis, Andre Rodrigues dos; Kyuma, Yukako; Sakakibara, Yutaka

    2013-12-01

    This study proposes a new treatment method to decompose persistent chemicals such as pentachlorophenol (PCP) in water, utilizing hydrogen peroxide present in aquatic plants to proceed the biological Fenton reaction. PCP was not effectively removed by aquatic plants. However, by adding 2.8 mM of Fe(2+), there was a rapid removal of PCP while at the same time consumption of endogenous hydrogen peroxide occurred. It was observed the increase of chloride ions formation in water-confirming the complete degradation of PCP. These results demonstrated that PCP was oxidized through a biological Fenton reaction, and hydrogen peroxide in aquatic plants was a key endogenous substance in treatment of refractory toxic pollutants.

  5. Oxidative and other posttranslational modifications in extracellular vesicle biology.

    Science.gov (United States)

    Szabó-Taylor, Katalin; Ryan, Brent; Osteikoetxea, Xabier; Szabó, Tamás G; Sódar, Barbara; Holub, Marcsilla; Németh, Andrea; Pálóczi, Krisztina; Pállinger, Éva; Winyard, Paul; Buzás, Edit I

    2015-04-01

    Extracellular vesicles including exosomes, microvesicles and apoptotic vesicles, are phospholipid bilayer surrounded structures secreted by cells universally, in an evolutionarily conserved fashion. Posttranslational modifications such as oxidation, citrullination, phosphorylation and glycosylation play diverse roles in extracellular vesicle biology. Posttranslational modifications orchestrate the biogenesis of extracellular vesicles. The signals extracellular vesicles transmit between cells also often function via modulating posttranslational modifications of target molecules, given that extracellular vesicles are carriers of several active enzymes catalysing posttranslational modifications. Posttranslational modifications of extracellular vesicles can also contribute to disease pathology by e.g. amplifying inflammation, generating neoepitopes or carrying neoepitopes themselves.

  6. Oxidation of pharmaceuticals by chlorine dioxide in biologically treated wastewater

    DEFF Research Database (Denmark)

    Hey, G.; Grabic, R.; Ledin, A.

    2012-01-01

    Biologically treated wastewater spiked with a mixture of 56 active pharmaceutical ingredients (APIs) was treated with 0–20mg/L chlorine dioxide (ClO2) solution in laboratory-scale experiments. Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended......O2, while in high COD effluent a significant increase in API oxidation was observed after treatment with 8mg/L ClO2. This study illustrates the successful degradation of several APIs during treatment of wastewater effluents with chlorine dioxide....

  7. Mechanistic modeling of vacuum UV advanced oxidation process in an annular photoreactor.

    Science.gov (United States)

    Crapulli, F; Santoro, D; Sasges, M R; Ray, A K

    2014-11-01

    A novel mechanistic model that describes the vacuum UV advanced oxidation process in an annular photoreactor initiated by 172 nm and 185 nm (in combination with 253.7 nm, with and without exogenous H2O2) is presented in this paper. The model was developed from first principles by incorporating the vacuum UV-AOP kinetics into the theoretical framework of in-series continuous flow stirred tank reactors. After conducting a sensitivity analysis, model predictions were compared against experiments conducted under a variety of conditions: (a) photo-induced formation of hydrogen peroxide by water photolysis at 172 nm (for both air- and oxygen-saturated conditions); (b) photo-induced formation of hydrogen peroxide by water photolysis at 185 + 253.7 nm (in the presence of formic acid, with and without the initial addition of hydrogen peroxide); (c) direct photolysis of hydrogen peroxide by 253.7 nm; (d) degradation of formic acid by 185 + 253.7 nm (with and without initial addition of hydrogen peroxide); and (e) degradation of formic acid by 253.7 nm (with the addition of exogenous hydrogen peroxide). In all cases, the model was able to accurately predict the time-dependent profiles of hydrogen peroxide and formic acid concentrations. Two newly recognized aspects associated with water photolysis were identified through the use of the validated model. Firstly, unlike the 185 nm and 253.7 nm cases, water photolysis by the 172 nm wavelength revealed a depth of photoactive water layer an order of magnitude greater (∼230-390 μm, depending on the specific operating conditions) than the 1-log photon penetration layer (∼18 μm). To further investigate this potentially very important finding, a computational fluid dynamics model was set up to assess the role of transport mechanisms and species distributions within the photoreactor annulus. The model confirmed that short-lived hydroxyl radicals were present at a radial distance far beyond the ∼18 μm photon

  8. TiO2 micro-nano-hybrid surface to alleviate biological aging of UV-photofunctionalized titanium

    Directory of Open Access Journals (Sweden)

    Iwasa F

    2011-06-01

    Full Text Available Fuminori Iwasa1, Naoki Tsukimura1, Yoshihiko Sugita1, Rajita Kodali Kanuru1, Katsutoshi Kubo1, Hafiz Hasnain1, Wael Att1,2, Takahiro Ogawa11Laboratory of Bone and Implant Sciences (LBIS, The Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA; 2Department of Prosthodontics, Dental School, Albert-Ludwigs University, Freiburg, GermanyAbstract: Bioactivity and osteoconductivity of titanium degrade over time after surface processing. This time-dependent degradation is substantial and defined as the biological aging of titanium. UV treatment has shown to reactivate the aged surfaces, a process known as photofunctionalization. This study determined whether there is a difference in the behavior of biological aging for titanium with micro-nano-hybrid topography and titanium with microtopography alone, following functionalization. Titanium disks were acid etched to create micropits on the surface. Micro-nano-hybrid surfaces were created by depositioning 300-nm diameter TiO2 nodules onto the micropits using a previously established self-assembly protocol. These disks were stored for 8 weeks in the dark to allow sufficient aging, then treated with UV light for 48 hours. Rat bone marrow–derived osteoblasts were cultured on fresh disks (immediately after UV treatment, 3-day-old disks (disks stored for 3 days after UV treatment, and 7-day-old disks. The rates of cell attachment, spread, proliferation, and levels of alkaline phosphatase activity, and calcium deposition were reduced by 30%–50% on micropit surfaces, depending on the age of the titanium. In contrast, 7-day-old hybrid surfaces maintained equivalent levels of bioactivity compared with the fresh surfaces. Both micropit and micro-nano-hybrid surfaces were superhydrophilic immediately after UV treatment. However, after 7 days, the micro-nano-hybrid surfaces became hydrorepellent

  9. Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

    Directory of Open Access Journals (Sweden)

    Oriol Gonzalez

    2016-10-01

    Full Text Available We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.g., 100 °C together with pulsed UV light irradiation employing a commercially available, 325 nm UV diode (square, 1 min period, 15 mA drive current signal, results in an up to 80-fold enhancement in sensitivity to nitrogen dioxide. Furthermore, this combined operation method allows for making savings in power consumption that range from 35% to over 80%. These results are achieved by exploiting the dynamics of sensor response under pulsed UV light, which convey important information for the quantitative analysis of nitrogen dioxide.

  10. Nitrate-reducing, sulfide-oxidizing bacteria as microbial oxidants for rapid biological sulfide removal.

    Science.gov (United States)

    De Gusseme, Bart; De Schryver, Peter; De Cooman, Michaël; Verbeken, Kim; Boeckx, Pascal; Verstraete, Willy; Boon, Nico

    2009-01-01

    The emission of hydrogen sulfide into the atmosphere of sewer systems induces the biological production of sulfuric acid, causing severe concrete corrosion. As a possible preventive solution, a microbial consortium of nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) was enriched in a continuously stirred tank reactor in order to develop a biological technique for the removal of dissolved sulfide. The consortium, dominated by Arcobacter sp., was capable of removing 99% of sulfide. Stable isotope fractioning of the sulfide indicated that the oxidation was a biological process. The capacity of the NR-SOB consortium for rapid removal of sulfide was demonstrated by using it as an inoculum in synthetic and real sewage. Removal rates up to 52 mg sulfide-S g VSS(-1) h(-1) were achieved, to our knowledge the highest removal rate reported so far for freshwater species in the absence of molecular oxygen. Further long-term incubation experiments revealed the capacity of the bacteria to oxidize sulfide without the presence of nitrate, suggesting that an oxidized redox reserve is present in the culture.

  11. Biological efficacy and toxic effect of emergency water disinfection process based on advanced oxidation technology.

    Science.gov (United States)

    Tian, Yiping; Yuan, Xiaoli; Xu, Shujing; Li, Rihong; Zhou, Xinying; Zhang, Zhitao

    2015-12-01

    An innovative and removable water treatment system consisted of strong electric field discharge and hydrodynamic cavitation based on advanced oxidation technologies was developed for reactive free radicals producing and waterborne pathogens eliminating in the present study. The biological efficacy and toxic effects of this advanced oxidation system were evaluated during water disinfection treatments. Bench tests were carried out with synthetic microbial-contaminated water, as well as source water in rainy season from a reservoir of Dalian city (Liaoning Province, China). Results showed that high inactivation efficiency of Escherichia coli (>5 log) could be obtained for synthetic contaminated water at a low concentration (0.5-0.7 mg L(-1)) of total oxidants in 3-10 s. The numbers of wild total bacteria (108 × 10(3) CFU mL(-1)) and total coliforms (260 × 10(2) MPN 100 mL(-1)) in source water greatly reduced to 50 and 0 CFU mL(-1) respectively after treated by the advanced oxidation system, which meet the microbiological standards of drinking water, and especially that the inactivation efficiency of total coliforms could reach 100%. Meanwhile, source water qualities were greatly improved during the disinfection processes. The values of UV254 in particular were significantly reduced (60-80%) by reactive free radicals. Moreover, the concentrations of possible disinfection by-products (formaldehyde and bromide) in treated water were lower than detection limits, indicating that there was no harmful effect on water after the treatments. These investigations are helpful for the ecotoxicological studies of advanced oxidation system in the treatments of chemical polluted water or waste water. The findings of this work suggest that the developed water treatment system is ideal in the acute phases of emergencies, which also could offer additional advantages over a wide range of applications in water pollution control.

  12. Chemical and biological oxidative effects of carbon black nanoparticles.

    Science.gov (United States)

    Koike, Eiko; Kobayashi, Takahiro

    2006-11-01

    Several studies show that ultrafine particles have a larger surface area than coarse particles, thus causing a greater inflammatory response. In this study, we investigated chemical and biological oxidative effects of nanoparticles in vitro. Carbon black (CB) nanoparticles with mean aerodynamic diameters of 14, 56, and 95nm were examined. The innate oxidative capacity of the CB nanoparticles was measured by consumption of dithiothreitol (DTT) in cell-free system. The expression of heme oxygenase-1 (HO-1) in rat alveolar type II epithelial cell line (SV40T2) and alveolar macrophages (AM) exposed to CB nanoparticles was measured by ELISA. DTT consumption of 14nm CB was higher than that of other CB nanoparticles having the same particle weight. However, DTT consumption was directly proportional to the particle surface area. HO-1 protein in SV40T2 cells was significantly increased by the 14nm and 56nm CB, however, 95nm CB did not affect. HO-1 protein in AM was significantly increased by the 14, 56, and 95nm CB. The increase in HO-1 expression was diminished by N-acetyl-l-cysteine (NAC) treatment of each CB nanoparticles before exposure although the difference between the effects of NAC-treated and untreated 14nm CB did not achieve significant. In conclusion, CB nanoparticles have innate oxidative capacity that may be dependent on the surface area. CB nanoparticles can induce oxidative stress in alveolar epithelial cells and AM that is more prominent with smaller particles. The oxidative stress may, at least partially, be mediated by surface function of particles.

  13. Antioxidant Cerium Oxide Nanoparticles in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Bryant C. Nelson

    2016-05-01

    Full Text Available Previously, catalytic cerium oxide nanoparticles (CNPs, nanoceria, CeO2-x NPs have been widely utilized for chemical mechanical planarization in the semiconductor industry and for reducing harmful emissions and improving fuel combustion efficiency in the automobile industry. Researchers are now harnessing the catalytic repertoire of CNPs to develop potential new treatment modalities for both oxidative- and nitrosative-stress induced disorders and diseases. In order to reach the point where our experimental understanding of the antioxidant activity of CNPs can be translated into useful therapeutics in the clinic, it is necessary to evaluate the most current evidence that supports CNP antioxidant activity in biological systems. Accordingly, the aims of this review are three-fold: (1 To describe the putative reaction mechanisms and physicochemical surface properties that enable CNPs to both scavenge reactive oxygen species (ROS and to act as antioxidant enzyme-like mimetics in solution; (2 To provide an overview, with commentary, regarding the most robust design and synthesis pathways for preparing CNPs with catalytic antioxidant activity; (3 To provide the reader with the most up-to-date in vitro and in vivo experimental evidence supporting the ROS-scavenging potential of CNPs in biology and medicine.

  14. CORONA-INDUCED PHOTOXIDATION OF ALCOHOLS AND HYDROCARBONS OVER TIO2 IN THE ABSENCE OF A UV LIGHT SOURCE - A NOVEL AND ENVIRONMENTALLY FRIENDLY METHOD FOR OXIDATION

    Science.gov (United States)

    Corona-induced photooxidation is a novel oxidation methodology for the efficient oxidation of alcohols and hydrocarbons utilizing the advantage of both the high oxidizing power of ozone formed in the reactor as well as the photooxidation capability of the UV light generated durin...

  15. Response of bacteriophage T7 biological dosimeter to dehydration and extraterrestrial solar UV radiation

    Science.gov (United States)

    Hegedüs, M.; Fekete, A.; Módos, K.; Kovács, G.; Rontó, Gy.; Lammer, H.; Panitz, C.

    2007-02-01

    The experiment "Phage and uracil response" (PUR) will be accommodated in the EXPOSE facility of the ISS. Bacteriophage T7/isolated T7 DNA will be exposed to different subsets of extreme environmental parameters in space, in order to study the Responses of Organisms to the Space Environment (ROSE). Launch into orbit is preceded by EXPOSE Experiment Verification Tests (EVT) to optimize the methods and the evaluation. Bacteriophage T7/isolated T7 DNA thin layers were exposed to vacuum ( 10-6Pa), to monochromatic (254 nm) and polychromatic (200-400 nm) UV radiation in air as well as in simulated space vacuum. Using neutral density (ND) filters dose-effect curves were performed in order to define the maximum doses tolerated. The effect of temperature fluctuation in vacuum was also studied. The structural/chemical effects on bacteriophage T7/isolated T7 DNA were analyzed by spectroscopic and microscopical methods. Characteristic changes in the absorption spectrum and in the electrophoretic pattern of phage/DNA have been detected indicating the damage of isolated and intraphage DNA. DNA damage was also determined by quantitative PCR (QPCR) using 555 and 3826 bp fragments of T7 DNA. We obtained substantial evidence that DNA lesions (e.g. strand breaks, DNA-protein cross-links, cyclobutane pirimidine dimers (CPDs) etc.) accumulate throughout exposure. Preliminary results suggest a synergistic action of space vacuum and UV radiation with DNA being the critical target.

  16. Improvement in performance of solution-processed indium-zinc-tin oxide thin-film transistors by UV/O3 treatment on zirconium oxide gate insulator

    Science.gov (United States)

    Naik, Bukke Ravindra; Avis, Christophe; Delwar Hossain Chowdhury, Md; Kim, Taehun; Lin, Tengda; Jang, Jin

    2016-03-01

    We studied solution-processed amorphous indium-zinc-tin oxide (a-IZTO) thin-film transistors (TFTs) with spin-coated zirconium oxide (ZrOx) as the gate insulator. The ZrOx gate insulator was used without and with UV/O3 treatment. The TFTs with an untreated ZrOx gate dielectric showed a saturation mobility (μsat) of 0.91 ± 0.29 cm2 V-1 s-1, a threshold voltage (Vth) of 0.28 ± 0.36 V, a subthreshold swing (SS) of 199 ± 37.17 mV/dec, and a current ratio (ION/IOFF) of ˜107. The TFTs with a UV/O3-treated ZrOx gate insulator exhibited μsat of 2.65 ± 0.43 cm2 V-1 s-1, Vth of 0.44 ± 0.35 V, SS of 133 ± 24.81 mV/dec, and ION/IOFF of ˜108. Hysteresis was 0.32 V in the untreated TFTs and was eliminated by UV/O3 treatment. Also, the leakage current decreased significantly when the IZTO TFT was coated onto a UV/O3-treated ZrOx gate insulator.

  17. UV-induced graft polymerization of acrylic acid in the sub-micronchannels of oxidized PET track-etched membrane

    Energy Technology Data Exchange (ETDEWEB)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A. [The L.N. Gumilyov Eurasian National University, Satpayev str., 2, 010008 Astana (Kazakhstan); Institute of Nuclear Physics Republic of Kazakhstan, 050032, Ibragimov str., 1, Almaty (Kazakhstan); Güven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey); Taltenov, Abzal A. [The L.N. Gumilyov Eurasian National University, Satpayev str., 2, 010008 Astana (Kazakhstan)

    2015-12-15

    In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H{sub 2}O{sub 2}/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid) (PAA) chains inside the membrane sub-micronchannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA) were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV–vis, ATR-FTIR, XPS spectroscopies and by SEM.

  18. Microwave accelerated synthesis of zinc oxide nanoplates and their enhanced photocatalytic activity under UV and solar illuminations

    Science.gov (United States)

    Anas, S.; Rahul, S.; Babitha, K. B.; Mangalaraja, R. V.; Ananthakumar, S.

    2015-11-01

    Photoactive zinc based nanoplates were developed through a rapid microwave synthesis. A low temperature thermolysis reaction in a surfactant medium was initially performed for producing microwave active zinc based polar precursors. Using these precursors, the zinc oxide nanopowder having platelet morphologies were prepared. The nanoplatelets exhibited random growth with non-polar (1 0 1) surface as the major growth plane. The structural and functional features of the resultant zinc oxide samples were monitored using XRD, FTIR, TEM and PL. The photocatalytic activities of the samples were investigated through the standard photoreduction kinetics using the methylene blue dye. The catalytic efficiencies of the samples were checked both under UV and sunlight. A comparative study was also performed with the standard TiO2 sample. The analyses revealed that the microwave derived zinc oxide have higher catalytic efficiency, than the standard titania samples, both under UV and sunlight illuminations. The unique nature of the zinc oxide non-polar surfaces can be attributed due to the presence of more active two dimensional open surfaces and the higher content of oxygen defect concentrations.

  19. Nanocrystalline Mg-doped Zinc Oxide Scintillator for UV detectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA uses detectors for a broad range of wavelengths from UV to gamma for applications in astrophysics, earth science, heliophysics, and planetary science. Mg-doped...

  20. Decolorization of Remazol Brilliant Blue Dye Effluent by Advanced Photo Oxidation Process (H2O2/UV system

    Directory of Open Access Journals (Sweden)

    A. S. Mahmoud

    2007-01-01

    Full Text Available Advanced photo oxidation processes hold great promise for the improved treatment of textile dye effluent. In this study, the effectiveness of a H2O2/UV system for the decolorization of remazol brilliant blue effluent was investigated by examining the optimum conditions for dye removal in two reactors (coil and conventional. The results showed that the coil reactor had a higher temperature profile than the conventional reactor. When the dye was fed into the reactors at 25˚C, UV radiation alone was not effective as the decolorization efficiency of the conventional reactor varied from 0.0 to 12.3%, while that of the coil reactor varied from 0.0 to 7.3%, depending on the residence time used. The effect of UV radiation at 100˚C was also negligible as the maximum decolorization efficiencies were 4.0 and 3.7% for the conventional and the coil reactors, respectively. Increasing the concentration of H2O2 increased decolorization efficiencies of both UV reactors. Dye decolorization also increased with residence time. More than 93% color removal of remazol brilliant blue dye was achieved with a residence time of 56 min and 100% decolorization achieved in 65 min using a H2O2 concentration of 12.50 mL Lˉ1.

  1. Degradation of antibiotic activity during UV/H2O2 advanced oxidation and photolysis in wastewater effluent.

    Science.gov (United States)

    Keen, Olya S; Linden, Karl G

    2013-11-19

    Trace levels of antibiotics in treated wastewater effluents may present a human health risk due to the rise of antibacterial activity in the downstream environments. Advanced oxidation has a potential to become an effective treatment technology for transforming trace antibiotics in wastewater effluents, but residual or newly generated antibacterial properties of transformation products are a concern. This study demonstrates the effect of UV photolysis and UV/H2O2 advanced oxidation on transformation of 6 antibiotics, each a representative of a different structural class, in pure water and in two different effluents and reports new or confirmatory photolysis quantum yields and hydroxyl radical rate constants. The decay of the parent compound was monitored with HPLC/ITMS, and the corresponding changes in antibacterial activity were measured using bacterial inhibition assays. No antibacterially active products were observed following treatment for four of the six antibiotics (clindamycin, ciprofloxacin, penicillin-G, and trimethoprim). The remaining two antibiotics (erythromycin and doxycycline) showed some intermediates with antibacterial activity at low treatment doses. The antibacterially active products lost activity as the UV dose increased past 500 mJ/cm(2). Active products were observed only in wastewater effluents and not in pure water, suggesting that complex secondary reactions controlled by the composition of the matrix were responsible for their formation. This outcome emphasizes the importance of bench-scale experiments in realistic water matrices. Most importantly, the results indicate that photosensitized processes during high dose wastewater disinfection may be creating antibacterially active transformation products from some common antibiotics.

  2. Photophysical and photochemical effects of UV and VUV photo-oxidation and photolysis on PET and PEN

    Science.gov (United States)

    Morgan, Andrew

    Polyethylene Terephthalate (PET) is a widely used polymer in the bottling, packaging, and clothing industry. In recent years an increasing global demand for PET has taken place due to the Solar Disinfection (SODIS) process. SODIS is a method of sterilizing fresh water into drinkable water. The PET bottles are used in the process to contain the water during solar irradiation due to its highly transparent optical property. Alongside PET, polyethylene 2,6-napthalate (PEN) is used in bottling and flexible electronic applications. The surface of PEN would need to be modified to control the hydrophilicity and the interaction it exudes as a substrate. The UV light absorption properties of PET and PEN are of great importance for many applications, and thus needs to be studied along with its photochemical resistance. The optical and chemical nature of PET was studied as it was treated by UV photo-oxidation, photo-ozonation, and photolysis under atmospheric pressure. Another investigation was also used to study PEN and PET as they are treated by vacuum UV (VUV) photo-oxidation, VUV photolysis, and remote oxygen reactions. The extent of the photoreactions' effect into the depth of the polymers is examined as treatment conditions are changed. The different experimental methods established the rate of several competing photoreactions on PET and PEN during irradiance, and their effect on the optical quality of the polymers.

  3. A study on near-UV blue photoluminescence in graphene oxide prepared by Langmuir–Blodgett method

    Energy Technology Data Exchange (ETDEWEB)

    Han, Feng; Yang, Shuming, E-mail: shuming.yang@mail.xjtu.edu.cn; Jing, Weixuan; Jiang, Zhuangde; Liu, Huan; Li, Lei

    2015-08-01

    Highlights: • GO films were deposited on substrates using LB method and reduced into rGO at 800 °C. • The PL of GO and rGO showed the near-UV blue emission. • This blue shift and decrease in PL was due to the newly formed sp{sup 2} clusters in rGO. - Abstract: The paper reports a study on a near-UV blue photoluminescence (PL) in graphene oxide (GO) films prepared by Langmuir–Blodgett (LB)-based method. GO films was reduced into reduced-graphene oxide (rGO) through thermal process at 800 °C. The surface morphology of both GO and rGO is characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray photoelectron spectroscopy (XPS) analysis shows the largely restoration of graphitic domains in GO after reduction. The photoluminescence (PL) of rGO shows the near-UV blue emission, which is blueshifted along with luminescent decreased as compared to GO. This blueshift and decrease in PL is mainly due to the newly formed sp{sup 2} clusters in rGO, which established percolation pathways between the sp{sup 2} clusters already present.

  4. Degradation pathways of aniline in aqueous solutions during electro-oxidation with BDD electrodes and UV/H2O2 treatment.

    Science.gov (United States)

    Benito, Aleix; Penadés, Aida; Lliberia, Josep Lluis; Gonzalez-Olmos, Rafael

    2017-01-01

    In this work, it has been studied the mineralization of aniline, a toxic substance of low biodegradability typically found in many industrial wastewaters, through electro-oxidation using boron doped diamond (BDD) electrodes and photo-oxidation (UV photolysis and UV/H2O2 treatments). It was observed that in electro-oxidation and UV/H2O2, it was feasible to reach aniline mineralizations higher than 85%. Two different degradation routes have been observed during the aniline oxidation in these two treatments. The first route was the mineralization pathway, in which aniline was oxidized to CO2, water and nitrate. The second route was the polyaniline pathway in which polyanilines of high molecular weight are formed. The intermediate compounds involved in both degradation routes are different depending on the treatment used. In the electro-oxidation, denitrification processes were also observed. From an economical point of view, electro-oxidation of aniline using BDD electrodes is more interesting than UV/H2O2 due it has an 87% lower operational cost. So, electro-oxidation using BDD electrodes seems to be a more suitable technique for the mineralization of wastewater containing aniline than UV or H2O2 based technologies.

  5. Mutagenic Effects of Iron Oxide Nanoparticles on Biological Cells.

    Science.gov (United States)

    Dissanayake, Niluka M; Current, Kelley M; Obare, Sherine O

    2015-09-30

    In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism's ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the OPEN ACCESS Int. J. Mol. Sci. 2015, 16 23483 transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells.

  6. Transformation of Contaminant Candidate List (CCL3) compounds during ozonation and advanced oxidation processes in drinking water: Assessment of biological effects.

    Science.gov (United States)

    Mestankova, Hana; Parker, Austa M; Bramaz, Nadine; Canonica, Silvio; Schirmer, Kristin; von Gunten, Urs; Linden, Karl G

    2016-04-15

    The removal of emerging contaminants during water treatment is a current issue and various technologies are being explored. These include UV- and ozone-based advanced oxidation processes (AOPs). In this study, AOPs were explored for their degradation capabilities of 25 chemical contaminants on the US Environmental Protection Agency's Contaminant Candidate List 3 (CCL3) in drinking water. Twenty-three of these were found to be amenable to hydroxyl radical-based treatment, with second-order rate constants for their reactions with hydroxyl radicals (OH) in the range of 3-8 × 10(9) M(-1) s(-1). The development of biological activity of the contaminants, focusing on mutagenicity and estrogenicity, was followed in parallel with their degradation using the Ames and YES bioassays to detect potential changes in biological effects during oxidative treatment. The majority of treatment cases resulted in a loss of biological activity upon oxidation of the parent compounds without generation of any form of estrogenicity or mutagenicity. However, an increase in mutagenic activity was detected by oxidative transformation of the following CCL3 parent compounds: nitrobenzene (OH, UV photolysis), quinoline (OH, ozone), methamidophos (OH), N-nitrosopyrolidine (OH), N-nitrosodi-n-propylamine (OH), aniline (UV photolysis), and N-nitrosodiphenylamine (UV photolysis). Only one case of formation of estrogenic activity was observed, namely, for the oxidation of quinoline by OH. Overall, this study provides fundamental and practical information on AOP-based treatment of specific compounds of concern and represents a framework for evaluating the performance of transformation-based treatment processes.

  7. Removal of phenolic endocrine disrupting compounds from waste activated sludge using UV, H2O2, and UV/H2O2 oxidation processes: effects of reaction conditions and sludge matrix.

    Science.gov (United States)

    Zhang, Ai; Li, Yongmei

    2014-09-15

    Removal of six phenolic endocrine disrupting compounds (EDCs) (estrone, 17β-estradiol, 17α-ethinylestradiol, estriol, bisphenol A, and 4-nonylphenols) from waste activated sludge (WAS) was investigated using ultraviolet light (UV), hydrogen peroxide (H2O2), and the combined UV/H2O2 processes. Effects of initial EDC concentration, H2O2 dosage, and pH value were investigated. Particularly, the effects of 11 metal ions and humic acid (HA) contained in a sludge matrix on EDC degradation were evaluated. A pseudo-first-order kinetic model was used to describe the EDC degradation during UV, H2O2, and UV/H2O2 treatments of WAS. The results showed that the degradation of the 6 EDCs during all the three oxidation processes fitted well with pseudo-first-order kinetics. Compared with the sole UV irradiation or H2O2 oxidation process, UV/H2O2 treatment was much more effective for both EDC degradation and WAS solubilization. Under their optimal conditions, the EDC degradation rate constants during UV/H2O2 oxidation were 45-197 times greater than those during UV irradiation and 11-53 times greater than those during H2O2 oxidation. High dosage of H2O2 and low pH were favorable for the degradation of EDCs. Under the conditions of pH = 3, UV wavelength = 253.7 nm, UV fluence rate = 0.069 mW cm(-2), and H2O2 dosage = 0.5 mol L(-1), the removal efficiencies of E1, E2, EE2, E3, BPA, and NP in 2 min were 97%, 92%, 95%, 94%, 89%, and 67%, respectively. The hydroxyl radical (OH) was proved to take the most important role for the removal of EDCs. Metal ions in sludge could facilitate the removal of EDCs during UV/H2O2 oxidation. Fe, Ag, and Cu ions had more obvious effects compared with other metal ions. The overall role of HA was dependent on the balance between its competition as organics and its catalysis/photosensitization effects. These indicate that the sludge matrix plays an important role in the degradation of EDCs.

  8. UV/TiO2 and UV/TiO2/chemical oxidant processes for the removal of humic acid, Cr and Cu in aqueous TiO2 suspensions.

    Science.gov (United States)

    Jung, J-T; Choi, J-Y; Chung, J; Lee, Y-W; Kim, J-O

    2009-03-01

    The objective of this study was to investigate the treatment efficiency of UV/TiO2 and UV/TiO2/chemical oxidant processes for the removal of humic acid and hazardous heavy metals in aqueous TiO2 suspensions. The reaction rate (k) of humic acid and hazardous heavy metals by UV/TiO2 was higher than that of UV illumination alone or TiO2 alone. The removal efficiency for humic acid and Cr(VI) at acid or neutral pH values was higher than that at basic pH values. However, the removal efficiency for Cu(II) at acid pH values was smaller compared with that at neutral or basic pH values. The reaction rate (k) of humic acid and hazardous heavy metals in the TiO2 concentration range of 0.1-0.3 g l(-1) increased with increasing TiO2 dosage. However, amounts higher than a TiO2 dosage of 0.3 g l(-1) reduced the removal efficiency for humic acid and hazardous heavy metals because of the shielding effect on the UV light penetration in the aqueous solution caused by the presence of excessive amounts of TiO2. The addition of oxidants to the UV/TiO2 system showed an increase in degradation efficiency for the treatment of humic acid and hazardous heavy metals. The optimal concentration of oxidants was: H2O2 50 mg l(-1), O3 20 g m(-3) and K2S2O8 50 mg l(-1), respectively. The degradation efficiency of UV/TiO2/oxidant systems for the removal of humic acid and hazardous heavy metals was much greater when H2O2 was used as the oxidant.

  9. DEVELOPMENT OF UV-VISIBLE SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF DASATINIB IN PHARMACEUTICAL FORMULATION AND BIOLOGICAL SAMPLES

    Directory of Open Access Journals (Sweden)

    B. Ramachandra

    2015-02-01

    Full Text Available A simple, economical, accurate, precise and reproducible UV-Visible spectrophotometric method for the routine estimation of dasatinib has been developed. The method is based on the formation of a bluish green colored complex by dasatinib in presence of MBTH reagent. The developed colored complex showed λmax at 630 nm. Beer’s law in the concentration range of 10 to 60 μg/ ml. Results of analysis were authenticated statistically as well as by recovery studies, which gave mean recovery between 99 to 100%. The method was successful in determining dasatinib in pharmaceutical formulation and biological samples, with an average recovery between 99 to 100 % respectively. The proposed method could find application to product development scientists in ongoing research; as well provide an additional tool for routine analysis of dasatinib.

  10. Erythropoietin, Forkhead Proteins, and Oxidative Injury: Biomarkers and Biology

    Directory of Open Access Journals (Sweden)

    Kenneth Maiese

    2009-01-01

    Full Text Available Oxidative stress significantly impacts multiple cellular pathways that can lead to the initiation and progression of varied disorders throughout the body. It therefore becomes imperative to elucidate the components and function of novel therapeutic strategies against oxidative stress to further clinical diagnosis and care. In particular, both the growth factor and cytokine erythropoietin (EPO, and members of the mammalian forkhead transcription factors of the O class (FoxOs, may offer the greatest promise for new treatment regimens, since these agents and the cellular pathways they oversee cover a range of critical functions that directly influence progenitor cell development, cell survival and degeneration, metabolism, immune function, and cancer cell invasion. Furthermore, both EPO and FoxOs function not only as therapeutic targets, but also as biomarkers of disease onset and progression, since their cellular pathways are closely linked and overlap with several unique signal transduction pathways. Yet, EPO and FoxOs may sometimes have unexpected and undesirable effects that can raise caution for these agents and warrant further investigations. Here we present the exciting as well as the complex role that EPO and FoxOs possess to uncover the benefits as well as the risks of these agents for cell biology and clinical care in processes that range from stem cell development to uncontrolled cellular proliferation.

  11. Erythropoietin, forkhead proteins, and oxidative injury: biomarkers and biology.

    Science.gov (United States)

    Maiese, Kenneth; Hou, Jinling; Chong, Zhao Zhong; Shang, Yan Chen

    2009-10-02

    Oxidative stress significantly impacts multiple cellular pathways that can lead to the initiation and progression of varied disorders throughout the body. It therefore becomes imperative to elucidate the components and function of novel therapeutic strategies against oxidative stress to further clinical diagnosis and care. In particular, both the growth factor and cytokine erythropoietin (EPO), and members of the mammalian forkhead transcription factors of the O class (FoxOs), may offer the greatest promise for new treatment regimens, since these agents and the cellular pathways they oversee cover a range of critical functions that directly influence progenitor cell development, cell survival and degeneration, metabolism, immune function, and cancer cell invasion. Furthermore, both EPO and FoxOs function not only as therapeutic targets, but also as biomarkers of disease onset and progression, since their cellular pathways are closely linked and overlap with several unique signal transduction pathways. Yet, EPO and FoxOs may sometimes have unexpected and undesirable effects that can raise caution for these agents and warrant further investigations. Here we present the exciting as well as the complex role that EPO and FoxOs possess to uncover the benefits as well as the risks of these agents for cell biology and clinical care in processes that range from stem cell development to uncontrolled cellular proliferation.

  12. Rethinking the Paleoproterozoic Great Oxidation Event: A Biological Perspective

    CERN Document Server

    Grula, John W

    2012-01-01

    Competing geophysical/geochemical hypotheses for how Earth's surface became oxygenated - organic carbon burial, hydrogen escape to space, and changes in the redox state of volcanic gases - are examined and a more biologically-based hypothesis is offered in response. It is argued that organic carbon burial is of minor importance to the accumulation of oxygen in a mainly anoxic world where aerobic respiration is not globally significant. Thus, for the Great Oxidation Event (GOE) ~ 2.4 Gyr ago, an increasing flux of O2 due to its production by an expanding population of cyanobacteria is parameterized as the primary source of O2. Various factors would have constrained cyanobacterial proliferation and O2 production during most of the Archean and therefore a long delay between the appearance of cyanobacteria and oxygenation of the atmosphere is to be expected. Destruction of O2 via CH4 oxidation in the atmosphere was a major O2 sink during the Archean, and the GOE is explained to a significant extent by a large dec...

  13. Removal of polar UV stabilizers in biological wastewater treatments and ecotoxicological implications.

    Science.gov (United States)

    Molins-Delgado, Daniel; Díaz-Cruz, M Silvia; Barceló, Damià

    2015-01-01

    The present study describes the development, validation and application of a fully automated analytical method based on on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (on line SPE-HPLC-MS/MS) to assess the removal efficiency in water works and the ecotoxicological implications derived of the two most used benzotriazole-class UV stabilizers (BZTs), namely 1H-benzotriazole (BZT) and 5-methyl-1H-benzotriazole (MeBZT). Influent and effluent wastewater samples from 20 wastewater treatment plants (WWTPs) were analyzed. Removal rates (RE%) and half-lives (t1/2) for each BZTs were calculated and correlated to the hydraulic retention time (HRT) of each plant. Both BZTs were detected in all influent and effluent samples (concentrations in the range 26.7 ng L(-1)-42.9 μg L(-1)), with the highest concentrations corresponding to MeBZT. Results indicated that both compounds were recalcitrant (RE% in the range 11.8-94.7%) and that no clear influence of HRT on removals could be drawn. Finally, the potential environmental risk posed by the levels of BZTs detected was evaluated calculating the hazard quotients (HQs) MeBZT was the only BZTs posing a risk to Vibrio fischeri, Daphnia galeata and Pimephales promelas.

  14. Iron and oxygen isotope fractionation during iron UV photo-oxidation: Implications for early Earth and Mars

    Science.gov (United States)

    Nie, Nicole X.; Dauphas, Nicolas; Greenwood, Richard C.

    2017-01-01

    Banded iron formations (BIFs) contain appreciable amounts of ferric iron (Fe3+). The mechanism by which ferrous iron (Fe2+) was oxidized into Fe3+ in an atmosphere that was globally anoxic is highly debated. Of the three scenarios that have been proposed to explain BIF formation, photo-oxidation by UV photons is the only one that does not involve life (the other two are oxidation by O2 produced by photosynthesis, and anoxygenic photosynthesis whereby Fe2+ is directly used as electron donor in place of water). We experimentally investigated iron and oxygen isotope fractionation imparted by iron photo-oxidation at a pH of 7.3. The iron isotope fractionation between precipitated Fe3+-bearing lepidocrocite and dissolved Fe2+ follows a Rayleigh distillation with an instantaneous 56Fe/54Fe fractionation factor of + 1.2 ‰. Such enrichment in the heavy isotopes of iron is consistent with the values measured in BIFs. We also investigated the nature of the mass-fractionation law that governs iron isotope fractionation in the photo-oxidation experiments (i.e., the slope of the δ56Fe-δ57Fe relationship). The experimental run products follow a mass-dependent law corresponding to the high-T equilibrium limit. The fact that a ∼3.8 Gyr old BIF sample (IF-G) from Isua (Greenland) falls on the same fractionation line confirms that iron photo-oxidation in the surface layers of the oceans was a viable pathway to BIF formation in the Archean, when the atmosphere was largely transparent to UV photons. Our experiments allow us to estimate the quantum yield of the photo-oxidation process (∼0.07 iron atom oxidized per photon absorbed). This yield is used to model iron oxidation on early Mars. As the photo-oxidation proceeds, the aqueous medium becomes more acidic, which slows down the reaction by changing the speciation of iron to species that are less efficient at absorbing UV-photons. Iron photo-oxidation in centimeter to meter-deep water ponds would take months to years to

  15. Experimental research on influencing factors of wet removal of NO from coal-fired flue gas by UV/H2O2 advanced oxidation process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Wet removal of NO from coal-fired flue gas by UV/H2O2 Advanced Oxidation Process (AOP) were investigated in a self-designed UV-bubble reactor. Several main influencing factors (UV intensity, H2O2 initial concentration, initial pH value, solution temperature, NO initial concentration, liquid-gas ratio and O2 percentage content) on the NO removal efficiency were studied. The results showed that UV intensity, H2O2 initial concentration, NO initial concentration and liquid-gas ratio are the main influencing factors. In the best conditions, the highest NO removal efficiency by UV/H2O2 advanced oxidation process could reach 82.9%. Based on the experimental study, the influencing mechanism of the relevant influencing factors were discussed in depth.

  16. Emulsion wastewater treatment by citrate enhanced UV/Fenton and combined with biological treatment%柠檬酸盐强化UV/Fenton-生物法处理乳化油废水

    Institute of Scientific and Technical Information of China (English)

    李继; 吕小梅; 张萍

    2011-01-01

    In the UV/Fenton process (UFP) treating artificial emulsion wastewater, the effects of citrate addition on the applicable pH range and effluent biodegradability were systematically investigated.In the citrate enhanced UV/Fenton process (CE-UFP), the applicable pH range was broadened to 4~8.When CE-UFP was carried out under 1.0 mM initial citrate concentration, the effluent BOD/COD ratio increased to 0.53, which is much higher than that of 0.32 with no citrate addition.When the effluent of CE-UFP and UFP were further separately treated with 8-hour biological treatment, the respective COD removal efficiencies were 78.7.0% and 96.0%.When 0~1.0 mM citrate was dosed at CE-UFP stage, the effluent COD after subsequent biological treatment may decrease from 293mg/L to 48mg/L, while no further decrease was observed with higher citrate dosage.All these results clearly indicate citrate can broaden the applicable pH range of UFP and enhance the biodegradability.%以乳化油配水为对象,研究了柠檬酸盐扩大UV/Fenton工艺的适用pH值范围与强化出水可生化性及与活性污泥法联用的效果.结果表明,柠檬酸盐可将UV/Fenton法的适用pH值范围扩大至4~8,且能提高UV/Fenton处理出水的可生化性.UV/Fenton处理后.原水BOD5/COD由0.02提高到0.32,投加1.0mmol/L柠檬酸钠后提高至0.53.UV/Fenton处理与经1.0mmol/L柠檬酸钠强化UV/Fenton处理出水经8h生物处理,COD去除率分别为78.7%,96.0%.柠檬酸钠浓度从0增加至1.0mmol/L时,经UV/Fenton处理过的出水再经生物处理出水的COD由293mg/L降低至48mg/L;继续增大时,COD基本保持不变.柠檬酸钠强化UV/Fenton处理可扩大pH值范围,改善废水的可生化性.

  17. Fe/Ti co-pillared clay for enhanced arsenite removal and photo oxidation under UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuan [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guang Dong Electric Power Design Institute, China Energy Engineering Group Co. Ltd., Guangzhou 510663 (China); Cai, Xiaojiao [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guo, Jingwei [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); The 718th Research Institute of CSIC, Handan 056027 (China); Zhou, Shimin [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Na, Ping, E-mail: naping@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2015-01-01

    Graphical abstract: - Highlights: • An iron and titanium co-pillared montmorillonite (Fe-Ti/MMT) was synthesized for arsenite removal. • Variety of characterization results indicated that Fe and Ti species were pillared in MMT. • A possible mechanism of arsenite adsorption/oxidation with UV light was established. • The participation of Fe component can promote the process of photocatalytic oxidation in Fe-Ti/MMT + As(III) system. • Fe-Ti/MMT can function as both photocatalyst and adsorbent for arsenite removal. - Abstract: A series of iron and titanium co-pillared montmorillonites (Fe-Ti/MMT) were prepared using hydrolysis of inserted titanium and different iron content in montmorillonite (MMT). The Fe-Ti/MMT were characterized by X-ray fluorescence, N{sub 2} adsorption and desorption, X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirming the effective insertion of Fe species and TiO{sub 2} in the MMT. The Fe-Ti/MMT was used to remove arsenite (As(III)) from aqueous solutions under different conditions. The result of As(III) adsorption under UV irradiation showed that the photo activity can be enhanced by incorporating Fe and Ti in MMT. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicated that the hydroxyl groups bonded to metal oxide (M–OH) played an important role in the adsorption of As(III)

  18. UV-visible spectroscopic estimation of photodegradation of rhodamine-B dye using tin(IV) oxide nanoparticles.

    Science.gov (United States)

    Sangami, G; Dharmaraj, N

    2012-11-01

    Nanocrystalline, tin(IV) oxide (SnO(2)) particles has been prepared by thermal decomposition of tin oxalate precursor obtained from the reactions of tin(IV) chloride and sodium oxalate using eggshell membrane (ESM). The as-prepared SnO(2) nanoparticles were characterized by thermal studies, transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman, FT-IR and UV-visible studies and used as a photocatalyst for the degradation of rhodamine-B (Rh-B) dye. The size of the prepared nanoparticles was in the range of 5-12nm as identified from the TEM images. Powder XRD data revealed the presence of a tetragonal, rutile crystalline phase of the tin(IV) oxide nanoparticles. Thermal analysis showed that the decomposition of tin oxalate precursor to yield the titled tin(IV) oxide nanoparticles was completed below 500°C. The extent of degradation of Rh-B in the presence of SnO(2) monitored by absorption spectral measurements demonstrated that 94.48% of the selected dye was degraded upon irradiation with UV light for 60 min.

  19. Mechanisms of Bond Cleavage during Manganese Oxide and UV Degradation of Glyphosate: Results from Phosphate Oxygen Isotopes and Molecular Simulations.

    Science.gov (United States)

    Jaisi, Deb P; Li, Hui; Wallace, Adam F; Paudel, Prajwal; Sun, Mingjing; Balakrishna, Avula; Lerch, Robert N

    2016-11-16

    Degradation of glyphosate in the presence of manganese oxide and UV light was analyzed using phosphate oxygen isotope ratios and density function theory (DFT). The preference of C-P or C-N bond cleavage was found to vary with changing glyphosate/manganese oxide ratios, indicating the potential role of sorption-induced conformational changes on the composition of intermediate degradation products. Isotope data confirmed that one oxygen atom derived solely from water was incorporated into the released phosphate during glyphosate degradation, and this might suggest similar nucleophilic substitution at P centers and C-P bond cleavage both in manganese oxide- and UV light-mediated degradation. The DFT results reveal that the C-P bond could be cleaved by water, OH(-) or (•)OH, with the energy barrier opposing bond dissociation being lowest in the presence of the radical species, and that C-N bond cleavage is favored by the formation of both nitrogen- and carbon-centered radicals. Overall, these results highlight the factors controlling the dominance of C-P or C-N bond cleavage that determines the composition of intermediate/final products and ultimately the degradation pathway.

  20. Effects of UV Aging on the Cracking of Titanium Oxide Layer on Poly(ethylene terephthalate) Substrate: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao; Gray, Matthew H.; Tirawat, Robert; Larsen, Ross E.; Chen, Fangliang

    2016-04-18

    Thin oxide and metal films deposited on polymer substrates is an emerging technology for advanced reflectors for concentrated solar power applications, due to their unique combination of light weight, flexibility and inexpensive manufacture. Thus far, there is little knowledge on the mechanical integrity or structural persistence of such multi-layer thin film systems under long-term environmental aging. In this paper, the cracking of a brittle titanium dioxide layer deposited onto elasto-plastic poly(ethylene terephthalate) (PET) substrate is studied through a combination of experiment and modeling. In-situ fragmentation tests have been conducted to monitor the onset and evolution of cracks both on pristine and on samples aged with ultraviolet (UV) light. An analytical model is presented to simulate the cracking behavior and to predict the effects of UV aging. Based on preliminary experimental observation, the effect of aging is divided into three aspects and analyzed independently: mechanical property degradation of the polymer substrate; degradation of the interlayer between substrate and oxide coating; and internal stress-induced cracks on the oxide coating.

  1. Advanced oxidation of five contaminants in water by UV/TiO2: Reaction kinetics and byproducts identification.

    Science.gov (United States)

    Alvarez-Corena, Jose R; Bergendahl, John A; Hart, Fred L

    2016-10-01

    The extent and kinetics of degradation of 1,4 dioxane, n-nitrosodimethylamine (NDMA), tris-2-chloroethyl phosphate (TCEP), gemfibrozil, and 17β estradiol in a prepared aqueous matrix by means of UV/TiO2 (ultraviolet light/titanium dioxide) oxidation was evaluated. Degussa P25 TiO2 was employed as a photocatalyst excited by UV light in a 1 L water-jacketed batch photoreactor. The rate of degradation was modeled using a pseudo-first order rate model and the Langmuir-Hinshelwood rate model with a high correlation. Degradation rate constants were found to be maximum at pH 5.0 and 1.5 g L(-)(1) TiO2 dose. For these conditions first order rate constants, values were as follows: 0.29 min(-1) for 1,4 dioxane, 0.50 min(-1) for NDMA, 0.12 min(-1) for TCEP, 0.61 min(-1) for gemfibrozil, and 0.53 min(-1) for 17β estradiol. While for the Langmuir-Hinshelwood rate model, the following constants were found: 0.11 Lmg(-1) and 2.81 mgL(-1) min(-1) for 1,4 dioxane, 0.12 Lmg(-1) and 4.35 mgL(-1) min(-1) for NDMA, 0.06 Lmg(-1) and 1.79 mgL(-1) min(-1) for TCEP, 0.21 Lmg(-1) and 3.27 mgL(-1) min(-1) for gemfibrozil, and 0.15 Lmg(-1) and 3.43 mgL(-1) min(-1) for 17β estradiol. In addition, specific byproducts of degradation were identified using GC/MS analysis. The results obtained from the kinetics analysis showed that UV/TiO2 oxidation is a promising process for treating trace organic contaminants in water, but further research is needed to better understand how to incorporate these findings into pilot and full-scale designs. The toxicity of oxidation byproducts, and their potential for interacting with other compounds should be considered in the treatment of contaminated waters using the UV/TiO2 oxidation process.

  2. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    Science.gov (United States)

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total dissolved polyphenols content of 0

  3. Synthesis of r-GO/TiO2 composites via the UV-assisted photocatalytic reduction of graphene oxide

    Science.gov (United States)

    Yang, Wein-Duo; Li, Yan-Ru; Lee, Yi-Chao

    2016-09-01

    Reduced graphene oxide/TiO2 (rGO/TiO2) composites were synthesized by combined TiO2 and graphene oxide (GO) under ultraviolet (UV) irradiation. The influences of TiO2 content on the reduction degree of GO during synthesis of the rGO/TiO2 composites were investigated and characterized by XRD, Raman, FTIR, SEM and TEM. It is shown that the XRD diffraction peak of 2θ at 10° of the as-prepared GO decreases with the increasing amount of TiO2 added. When the weight ratio of GO:TiO2 is 2:1, the XRD diffraction peak of 2θ at 10° of graphene oxide almost disappears. At a GO:TiO2 of 1:2, the OH functional groups, carboxylic and carbonyl, on the edge of the graphene oxide are effectively removed. Moreover, a morphological study shows the observation of graphene has a corrugated titanium oxide load and intercalation. The as-prepared rGO/TiO2 obtained from weight ratios of GO: TiO2 at 1: 2.5 showed a specific capacitance of 226.45 Fg-1 at a scan rate of 10 mV s-1 in 1 M H2SO4 electrolyte solution.

  4. [Nitric Oxide in Modulation of Crystallogenic Propeties of Biological Fluid].

    Science.gov (United States)

    Martusevich, A K; Kovaleva, L K; Davyduk, A V

    2016-01-01

    The aim of this work was a comparative analysis of the influence of different NO forms on dehydration structurization of human blood serum. Blood specimens from 15 healthy people were treated by NO-containing gas flow (800 and 80 ppm) generated with the "Plazon" unit, experimental NO-generator (20, 50, 75 and 100 ppm) and by water solution of thiol-containing dinitrosyl iron complexes (3 mM/L). The influence of blood sodium on blood serum crystallization in original and NO-treated blood specimens was estimated. It was found, that the effect of NO on crystallogenic properties of blood serum depends directly on its concentration and form (free or bound), as well as on the presence of reactive oxygen species in gas flow. The most pronounced stimulating effect was observed for the bound form of NO--dinitrosyl iron complexes with glutathione ligands. Low NO concentrations modulated crystallogenic properties of blood serum and the most optimal stimulating action was demonstrated in gas flow containing 20 ppm nitric oxide. In contrast, high NO concentration (800 ppm) inhibited the crystallogenic activity of biological fluid with multiply increasing of structural elements destruction leading to the formation of an additional belt in marginal zone of dehydrated specimens.

  5. Photocatalytic decolorization of azo-dye with zinc oxide powder in an external UV light irradiation slurry photoreactor

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Junpei [Research Center for Biochemical and Environmental Engineering, Department of Applied Chemistry, Toyo University, Kawagoe, Saitama 350-8585 (Japan); Tokumura, Masahiro [Research Center for Biochemical and Environmental Engineering, Department of Applied Chemistry, Toyo University, Kawagoe, Saitama 350-8585 (Japan); Znad, Hussein T. [Research Center for Biochemical and Environmental Engineering, Department of Applied Chemistry, Toyo University, Kawagoe, Saitama 350-8585 (Japan); Kawase, Yoshinori [Research Center for Biochemical and Environmental Engineering, Department of Applied Chemistry, Toyo University, Kawagoe, Saitama 350-8585 (Japan)]. E-mail: bckawase@mail.eng.toyo.ac.jp

    2006-11-02

    Photocatalytic decolorization of azo-dye Orange II in water has been examined in an external UV light irradiation slurry photoreactor using zinc oxide (ZnO) as a semiconductor photocatalyst. The effects of process parameters such as light intensity, initial dye concentration, photocatalyst loading and initial solution pH on the decolorization rate of Orange II have been systematically investigated. A two-stage photocatalytic decolorization of Orange II, the first stage of fast decolorization rate and the subsequent second stage of rather slow decolorization rate, was found. The efficiency of decolorization of Orange II increased as initial Orange II concentration decreased and UV light intensity increased. There was the optimal ZnO concentration being around 1000 mg L{sup -1}. The optimal pH was around 7.7, which was at the natural pH of the dye solution. The effect of aeration rate on the decolorization of Orange II has been also investigated and the enhancement of decolorization of Orange II with increasing aeration rate was found. By using a model for the light intensity profile in the external UV light irradiation slurry photoreactor, the simulation model for the decolorization of Orange II with ZnO photocatalyst has been developed. The proposed model in which the slow decolorization in the second stage as well as the initial fast decolorization is also taken into account could simulate the experimental results for UV light irradiation satisfactorily. The proposed simulation model in which the change of light intensity with time due to the decolorization of Orange II and the light scatter due to solid photocatalysts are considered will be very useful for practical engineering design of the slurry photoreactor of wastewater including textile dyes.

  6. UV/TiO₂ photocatalytic oxidation of recalcitrant organic matter: effect of salinity and pH.

    Science.gov (United States)

    Muthukumaran, Shobha; Song, Lili; Zhu, Bo; Myat, Darli; Chen, Jin-Yuan; Gray, Stephen; Duke, Mikel

    2014-01-01

    Photocatalytic oxidation processes have interest for water treatment since these processes can remove recalcitrant organic compounds and operate at mild conditions of temperature and pressure. However, performance under saline conditions present in many water resources is not well known. This study aims to explore the basic effects of photocatalysis on the removal of organic matter in the presence of salt. A laboratory-scale photocatalytic reactor system, employing ultraviolet (UV)/titanium dioxide (TiO₂) photocatalysis was evaluated for its ability to remove the humic acid (HA) from saline water. The particle size and zeta potential of TiO₂ under different conditions including solution pH and sodium chloride (NaCl) concentrations were characterized. The overall degradation of organics over the NaCl concentration range of 500-2,000 mg/L was found to be 80% of the non-saline equivalent after 180 min of the treatment. The results demonstrated that the adsorption of HA onto the TiO₂ particles was dependent on both the pH and salinity due to electrostatic interaction and highly unstable agglomerated dispersion. This result supports UV/TiO₂ as a viable means to remove organic compounds, but the presence of salt in waters to be treated will influence the performance of the photocatalytic oxidation process.

  7. Fabrication of silver nanowires and metal oxide composite transparent electrodes and their application in UV light-emitting diodes

    Science.gov (United States)

    Yan, Xingzhen; Ma, Jiangang; Xu, Haiyang; Wang, Chunliang; Liu, Yichun

    2016-08-01

    In this paper, we prepared the silver nanowires (AgNWs)/aluminum-doped zinc oxide (AZO) composite transparent conducting electrodes for n-ZnO/p-GaN heterojunction light emitting-diodes (LEDs) by drop casting AgNW networks and subsequent atomic layer deposition (ALD) of AZO at 150 °C. The contact resistances between AgNWs were dramatically reduced by pre-annealing in the vacuum chamber before the ALD of AZO. In this case, AZO works not only as the conformal passivation layer that protects AgNWs from oxidation, but also as the binding material that improves AgNWs adhesion to substrates. Due to the localized surface plasmons (LSPs) of the AgNWs resonant coupling with the ultraviolet (UV) light emission from the LEDs, a higher UV light extracting efficiency is achieved from LEDs with the AgNWs/AZO composite electrodes in comparison with the conventional AZO electrodes. Additionally, the antireflective nature of random AgNW networks in the composite electrodes caused a broad output light angular distribution, which could be of benefit to certain optoelectronic devices like LEDs and solar cells.

  8. Evaluation of machine learning algorithms for classification of primary biological aerosol using a new UV-LIF spectrometer

    Science.gov (United States)

    Ruske, Simon; Topping, David O.; Foot, Virginia E.; Kaye, Paul H.; Stanley, Warren R.; Crawford, Ian; Morse, Andrew P.; Gallagher, Martin W.

    2017-03-01

    Characterisation of bioaerosols has important implications within environment and public health sectors. Recent developments in ultraviolet light-induced fluorescence (UV-LIF) detectors such as the Wideband Integrated Bioaerosol Spectrometer (WIBS) and the newly introduced Multiparameter Bioaerosol Spectrometer (MBS) have allowed for the real-time collection of fluorescence, size and morphology measurements for the purpose of discriminating between bacteria, fungal spores and pollen.This new generation of instruments has enabled ever larger data sets to be compiled with the aim of studying more complex environments. In real world data sets, particularly those from an urban environment, the population may be dominated by non-biological fluorescent interferents, bringing into question the accuracy of measurements of quantities such as concentrations. It is therefore imperative that we validate the performance of different algorithms which can be used for the task of classification.For unsupervised learning we tested hierarchical agglomerative clustering with various different linkages. For supervised learning, 11 methods were tested, including decision trees, ensemble methods (random forests, gradient boosting and AdaBoost), two implementations for support vector machines (libsvm and liblinear) and Gaussian methods (Gaussian naïve Bayesian, quadratic and linear discriminant analysis, the k-nearest neighbours algorithm and artificial neural networks).The methods were applied to two different data sets produced using the new MBS, which provides multichannel UV-LIF fluorescence signatures for single airborne biological particles. The first data set contained mixed PSLs and the second contained a variety of laboratory-generated aerosol.Clustering in general performs slightly worse than the supervised learning methods, correctly classifying, at best, only 67. 6 and 91. 1 % for the two data sets respectively. For supervised learning the gradient boosting algorithm was

  9. Circulating biologically active oxidized phospholipids show on-going and increased oxidative stress in older male mice

    Directory of Open Access Journals (Sweden)

    Jinbo Liu

    2013-01-01

    Significance: Oxidatively modified phospholipids are increased in the circulation during common, mild oxidant stresses of aging, or in male compared to female animals. Turnover of these biologically active phospholipids by rapid transport into liver and kidney is unchanged, so circulating levels reflect continuously increased production.

  10. PHOTODEGRADATION OF 3-(3,4- DICHLOROPHENYL-1,1-DIMETHYLUREA IN PRESENCE OF NATURAL IRON OXIDE UNDER UV IRRADIATION

    Directory of Open Access Journals (Sweden)

    H MECHAKRA

    2014-07-01

    Full Text Available Heterogeneous photodegradation of Linuron under UV irradiation was investigated. Natural iron oxide (NIO was used in this study, to take a closer look at its adsorption capacity in the dark. The results obtained showed that the substrate photolysis is very slowly in artificial light (λ = 365nm. However, the introduction of oxalic acid (Ox in the system improves the degradation process greatly. The dependence of Linuron degradation was attributed to the formation of the dissolved Fe-Ox in the solution and the adsorbed Fe-Ox on the surface of natural iron oxide. The effect of different parameters such as the oxalate concentration, pH and initial concentration of NIO on the photodegradation were studied in the iron oxide/ oxalate system. The results demonstrated that the optimal pH should be in the range of 2–3. The system efficiency is directly proportional to the concentration of polycarboxylate ions. The optimum mass of NIO used a good inducing disappearance of linuron was 1g.L-1. Furthermore, changes in the concentrations of Fe3+ and Fe2+ ions in the photo-reaction were also strongly dependent on the initial oxalate and iron oxide concentration. The use of 2% of isopropanol as a scavenger confirmed the intervention of hydroxyl radicals in the photodegradation of linuron.

  11. Production of biologically safe and mechanically improved reduced graphene oxide/hydroxyapatite composites

    Science.gov (United States)

    Elif, Öztürk; Belma, Özbek; İlkay, Şenel

    2017-01-01

    As research trends included the improvement of the mechanical properties of hydroxyapatite (HA) for biological applications, HA was reinforced with different concentrations of reduced graphene oxide (RGO) in HA. In this context, graphene oxide was synthesized using the chemical exfoliation method and reduced using an environmentally safe and green method. As a green method, RGO was obtained using Melissa officinalis (melisa) extract and used as a second phase combination to the HA structure. RGO-HA composites with different concentrations of RGO in HA (0.25, 0.5, 1.0, 2.0% wt.) were prepared using the liquid precipitation method. Then they were pelleted and sintered. Characterization studies were carried out using UV-vis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zetasizer (ZS), x-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The mechanical properties of the composites were analyzed using a universal testing machine. Compared to pure HA, the compressive strength values of composites were increased significantly with the increase in RGO content. The optimum increase was observed for the RGO-HA (1%) composite, which was 3.2 times higher than the pure HA sample. Therefore, the RGO-HA (1%) composite was chosen as the best composition, and its cytotoxic and proliferative effects were examined using a minimum essential media elution test and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results showed that RGO-HA (1%) composites are biocompatible and even though they are proliferative at concentrations lower than 25%.

  12. Plasmonics in the UV range with Rhodium nanocubes

    Science.gov (United States)

    Zhang, X.; Gutiérrez, Y.; Li, P.; Barreda, Á. I.; Watson, A. M.; Alcaraz de la Osa, R.; Finkelstein, G.; González, F.; Ortiz, D.; Saiz, J. M.; Sanz, J. M.; Everitt, H. O.; Liu, J.; Moreno, F.

    2016-04-01

    Plasmonics in the UV-range constitutes a new challenge due to the increasing demand to detect, identify and destroy biological toxins, enhance biological imaging, and characterize semiconductor devices at the nanometer scale. Silver and aluminum have an efficient plasmonic performance in the near UV region, but oxidation reduces its performance in this range. Recent studies point out rhodium as one of the most promising metals for this purpose: it has a good plasmonic response in the UV and, as gold in the visible, it presents a low tendency to oxidation. Moreover, its easy fabrication through chemical means and its potential for photocatalytic applications, makes this material very attractive for building plasmonic tools in the UV. In this work, we will show an overview of our recent collaborative research with rhodium nanocubes (NC) for Plasmonics in the UV.

  13. Impact of UV/H2O2 pre-oxidation on the formation of haloacetamides and other nitrogenous disinfection byproducts during chlorination.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Krasner, Stuart W; Mitch, William A

    2014-10-21

    Haloacetamides (HAcAms), an emerging class of nitrogen-based disinfection byproducts (N-DBPs) of health concern in drinking water, have been found in drinking waters at μg/L levels. However, there is a limited understanding about the formation, speciation, and control of halogenated HAcAms. Higher ultraviolet (UV) doses and UV advanced oxidation (UV/H2O2) processes (AOPs) are under consideration for the treatment of trace organic pollutants. The objective of this study was to examine the potential of pretreatment with UV irradiation, H2O2 oxidation, and a UV/H2O2 AOP for minimizing the formation of HAcAms, as well as other emerging N-DBPs, during postchlorination. We investigated changes in HAcAm formation and speciation attributed to UV, H2O2 or UV/H2O2 followed by the application of free chlorine to quench any excess hydrogen peroxide and to provide residual disinfection. The results showed that low-pressure UV irradiation alone (19.5-585 mJ/cm(2)) and H2O2 preoxidation alone (2-20 mg/L) did not significantly change total HAcAm formation during subsequent chlorination. However, H2O2 preoxidation alone resulted in diiodoacetamide formation in two iodide-containing waters and increased bromine utilization. Alternatively, UV/H2O2 preoxidation using UV (585 mJ/cm(2)) and H2O2 (10 mg/L) doses typically employed for trace contaminant removal controlled the formation of HAcAms and several other N-DBPs in drinking water.

  14. Size-Dependent Filling Behavior of UV-Curable Di(meth)acrylate Resins into Carbon-Coated Anodic Aluminum Oxide Pores of around 20 nm.

    Science.gov (United States)

    Nakagawa, Masaru; Nakaya, Akifumi; Hoshikawa, Yasuto; Ito, Shunya; Hiroshiba, Nobuya; Kyotani, Takashi

    2016-11-09

    Ultraviolet (UV) nanoimprint lithography is a promising nanofabrication technology with cost efficiency and high throughput for sub-20 nm size semiconductor, data storage, and optical devices. To test formability of organic resist mask patterns, we investigated whether the type of polymerizable di(meth)acrylate monomer affected the fabrication of cured resin nanopillars by UV nanoimprinting using molds with pores of around 20 nm. We used carbon-coated, porous, anodic aluminum oxide (AAO) films prepared by electrochemical oxidation and thermal chemical vapor deposition as molds, because the pore diameter distribution in the range of 10-40 nm was suitable for combinatorial testing to investigate whether UV-curable resins comprising each monomer were filled into the mold recesses in UV nanoimprinting. Although the UV-curable resins, except for a bisphenol A-based one, detached from the molds without pull-out defects after radical photopolymerization under UV light, the number of cured resin nanopillars was independent of the viscosity of the monomer(s) in each resin. The number of resin nanopillars increased and their diameter decreased as the number of hydroxy groups in the aliphatic diacrylate monomers increased. It was concluded that the filling of the carbon-coated pores having diameters of around 20 nm with UV-curable resins was promoted by the presence of hydroxy groups in the aliphatic di(meth)acrylate monomers.

  15. Monitoring of TiO2-catalytic UV-LED photo-oxidation of cyanide contained in mine wastewater and leachate.

    Science.gov (United States)

    Kim, Seong Hee; Lee, Sang Woo; Lee, Gye Min; Lee, Byung-Tae; Yun, Seong-Taek; Kim, Soon-Oh

    2016-01-01

    A photo-oxidation process using UV-LEDs and TiO2 was studied for removal of cyanide contained in mine wastewater and leachates. This study focused on monitoring of a TiO2-catalyzed LED photo-oxidation process, particularly emphasizing the effects of TiO2 form and light source on the efficiency of cyanide removal. The generation of hydroxyl radicals was also examined during the process to evaluate the mechanism of the photo-catalytic process. The apparent removal efficiency of UV-LEDs was lower than that achieved using a UV-lamp, but cyanide removal in response to irradiation as well as consumption of electrical energy was observed to be higher for UV-LEDs than for UV-lamps. The Degussa P25 TiO2 showed the highest performance of the TiO2 photo-catalysts tested. The experimental results indicate that hydroxyl radicals oxidize cyanide to OCN(-), NO2(-), NO3(-), HCO3(-), and CO3(2-), which have lower toxicity than cyanide. In addition, the overall efficacy of the process appeared to be significantly affected by diverse operational parameters, such as the mixing ratio of anatase and rutile, the type of gas injected, and the number of UV-LEDs used.

  16. Assessment of the UV/Cl2 advanced oxidation process for the degradation of the emerging contaminants amitriptyline hydrochloride, methyl salicylate and 2-phenoxyethanol in water systems.

    Science.gov (United States)

    Javier Benitez, F; Real, Francisco J; Acero, Juan L; Casas, Francisco

    2016-12-26

    Three emerging contaminants (amitriptyline hydrochloride (AH), methyl salicylate (MS) and 2-phenoxyethanol (PE)) frequently found in wastewaters were selected to be individually degraded in ultra-pure water by the advanced oxidation process (AOP) constituted by the combination of UV radiation and chlorine. The influence of pH, initial chlorine concentration and nature of the contaminants was firstly explored. The trend for the reactivity of the selected compounds was deduced: AH > MS > PE. A later kinetic study was carried out focused on the evaluation of the first-order rate constants and the determination of the partial contribution to the global reaction of the direct photochemical pathway and the radical pathway. In a second stage, the simultaneous oxidation of mixtures of the selected contaminants in several types of water was also performed by the same combination UV/Cl2. The efficiency of this combined system UV/Cl2 was compared to other oxidants such as the UV/[Formula: see text] and UV/H2O2 AOPs, and the influence of the operating variables was discussed. Results confirmed that the UV/Cl2 system provides higher elimination efficiencies among the AOPs tested. The presence of dissolved organic matter and bicarbonate ions in the water matrix caused a decrease in the treatment efficiency.

  17. Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters.

    Science.gov (United States)

    Sigaev, Vladimir N; Golubev, Nikita V; Ignat'eva, Elena S; Paleari, Alberto; Lorenzi, Roberto

    2014-01-01

    Wide-bandgap nanocrystals are an inexhaustible source of tuneable functions potentially addressing most of the demand for new light emitting systems. However, the implementation of nanocrystal properties in real devices is not straightforward if a robust and stable optical component is required as a final result. The achievement of efficient light emission from dense dispersions of Ga-oxide nanocrystals in UV-grade glass can be a breakthrough in this regard. Such a result would permit the fabrication of low cost UV-to-visible converters for monitoring UV-emitting events on a large-scale - from invisible hydrogen flames to corona dispersions. From this perspective, γ-Ga₂O₃ nanocrystals are developed by phase separation in Ga-alkali-germanosilicate glasses, obtaining optical materials based on a UV transparent matrix. Band-to-band UV-excitation of light emission from donor-acceptor pair (DAP) recombination is investigated for the first time in embedded γ-Ga₂O₃. The analysis of the decay kinetics gives unprecedented evidence that nanosized confinement of DAP recombination can force a nanophase to the efficient response of exactly balanced DAPs. The results, including a proof of concept of UV-to-visible viewer, definitely demonstrate the feasibility of workable glass-based fully inorganic nanostructured materials with emission properties borrowed from Ga₂O₃ single-crystals and tailored by the nanocrystal size.

  18. Endogenous nitric oxide synthesis: biological functions and pathophysiology.

    Science.gov (United States)

    Bredt, D S

    1999-12-01

    Modern molecular biology has revealed vast numbers of large and complex proteins and genes that regulate body function. By contrast, discoveries over the past ten years indicate that crucial features of neuronal communication, blood vessel modulation and immune response are mediated by a remarkably simple chemical, nitric oxide (NO). Endogenous NO is generated from arginine by a family of three distinct calmodulin- dependent NO synthase (NOS) enzymes. NOS from endothelial cells (eNOS) and neurons (nNOS) are both constitutively expressed enzymes, whose activities are stimulated by increases in intracellular calcium. Immune functions for NO are mediated by a calcium-independent inducible NOS (iNOS). Expression of iNOS protein requires transcriptional activation, which is mediated by specific combinations of cytokines. All three NOS use NADPH as an electron donor and employ five enzyme cofactors to catalyze a five-electron oxidation of arginine to NO with stoichiometric formation of citrulline. The highest levels of NO throughout the body are found in neurons, where NO functions as a unique messenger molecule. In the autonomic nervous system NO functions NO functions as a major non-adrenergic non-cholinergic (NANC) neurotransmitter. This NANC pathway plays a particularly important role in producing relaxation of smooth muscle in the cerebral circulation and the gastrointestinal, urogenital and respiratory tracts. Dysregulation of NOS activity in autonomic nerves plays a major role in diverse pathophysiological conditions including migraine headache, hypertrophic pyloric stenosis and male impotence. In the brain, NO functions as a neuromodulator and appears to mediate aspects of learning and memory. Although endogenous NO was originally appreciated as a mediator of smooth muscle relaxation, NO also plays a major role in skeletal muscle. Physiologically muscle-derived NO regulates skeletal muscle contractility and exercise-induced glucose uptake. nNOS occurs at the

  19. Oxidation by-products and ecotoxicity assessment during the photodegradation of fenofibric acid in aqueous solution with UV and UV/H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, Javier [Department of Chemical Engineering, University of Alcala, E-28771 Alcala de Henares (Spain); Agueera, Ana; Mar Gomez-Ramos, Maria del [Department of Analytical Chemistry, University of Almeria, E-04010 Almeria (Spain); Fernandez Alba, Amadeo R. [Department of Analytical Chemistry, University of Almeria, E-04010 Almeria (Spain); Advanced Study Institute of Madrid, IMDEA-Agua, Parque Cientifico Tecnologico, E-28805 Alcala de Henares, Madrid (Spain); Garcia-Calvo, Eloy [Department of Chemical Engineering, University of Alcala, E-28771 Alcala de Henares (Spain); Advanced Study Institute of Madrid, IMDEA-Agua, Parque Cientifico Tecnologico, E-28805 Alcala de Henares, Madrid (Spain); Rosal, Roberto, E-mail: roberto.rosal@uah.es [Department of Chemical Engineering, University of Alcala, E-28771 Alcala de Henares (Spain); Advanced Study Institute of Madrid, IMDEA-Agua, Parque Cientifico Tecnologico, E-28805 Alcala de Henares, Madrid (Spain)

    2011-10-30

    Highlights: {yields} UV and UV/H{sub 2}O{sub 2} photolysis of fenofibric acid. {yields} Identification of reaction intermediates using exact mass measurements. {yields} UV/H{sub 2}O{sub 2} removed toxicity towards Pseudokirchneriella subcapitata. {yields} Irradiated samples contain a number of chlorinated products. - Abstract: The degradation of an aqueous solution of fenofibric acid was investigated using ultraviolet (UV) photolysis and UV/H{sub 2}O{sub 2} with a low-pressure mercury lamp. We obtained quantum yields at different temperatures and the rate constant for the reaction of fenofibric acid with hydroxyl radicals. The maximum radical exposure per fluence ratio obtained was 1.4 x 10{sup -10} M L{sup -1} mW{sup -1}. Several reaction intermediates were detected by means of exact mass measurements performed by liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (LC-ESI-QTOF-MS). UV and UV/H{sub 2}O{sub 2} pathways involve the decarboxylation of fenofibric acid to 4-chloro-4'-(1-hydroxy-1-methylethyl)benzophenone and other minor products, predominantly chlorinated aromatics. We detected several intermediates from reactions with hydroxyl radicals and some lower molecular weight products from the scission of the carbonyl carbon-to-aromatic-carbon bond. We recorded high toxicity in UV irradiated samples for the growth of Pseudokirchneriella subcapitata even after the total depletion of fenofibric acid; this was probably due to the presence of chlorinated aromatics. A degree of toxicity reappeared in highly irradiated UV/H{sub 2}O{sub 2} samples, probably because of the formation of ring-opening products. The degree of mineralization was closely related to that of dechlorination and reached values of over 50% after 3-4 min before stabilizing thereafter.

  20. Responses of photosynthetic properties and chloroplast ultrastructure of two moss crusts from a desert biological soil crust to supplementary UV-B radiation

    Science.gov (United States)

    Hui, Rong; Li, Xinrong; Zhao, Yang; Pan, Yanxia

    2016-04-01

    Our understanding of plant responses to supplementary ultraviolet-B (UV-B) radiation due to stratospheric ozone depletion has improved over recent decades. However, research on biological soil crusts (BSCs) is scarce and it remains controversial. Laboratory studies were conducted to investigate the influence of UV-B radiation on the Bryum argenteum and Didymodon vinealis isolated from BSCs, which are both dominant species in moss crusts found within patches of shrubs and herbs in the Tengger Desert of northern China. The aim of the current work was to evaluate whether supplementary UV-B radiation affected photosynthetic properties and chloroplast ultrastructure of two moss crusts and whether response differences were observed between the crusts. Four levels of UV-B radiation of 2.75 (control), 3.08, 3.25, and 3.41 W m-2 was achieved using fluorescence tube systems for 10 days, simulating 0, 6, 9, and 12% of stratospheric ozone at the latitude of Shapotou, respectively. We measured photosynthetic apparatus as assessed by chlorophyll a fluorescence parameters, photosynthetic pigment contents, and observations of chloroplast ultrastructure. Additionally, soluble proteins and UV-B absorbing compounds were simultaneously investigated. The results of this study showed that chlorophyll a fluorescence parameters (i.e., the maximal quantum yield of PSII photochemistry, the effective quantum yield of PSII photochemistry, and photochemical quenching coefficient), photosynthetic pigment contents, soluble protein contents, total flavonoid contents and the ultrastructure were negatively influenced by elevated UV-B radiation and the degree of detrimental effects significantly increased with the intensity of UV-B radiation. Moreover, results demonstrated that the negative effects on photosynthesis and chloroplast ultrastructure were more serious in B. argenteum than that in D. vinealis. These results may not only provide a potential mechanism for supplemental UV-B effects on

  1. Dimethoate modifies enhanced UV-B effects on growth, photosynthesis and oxidative stress in mung bean (Vigna radiata L.) seedlings: implication of salicylic acid.

    Science.gov (United States)

    Singh, Vijay Pratap; Kumar, Jitendra; Singh, Samiksha; Prasad, Sheo Mohan

    2014-11-01

    The present study is aimed to investigate implication of salicylic acid (SA) in regulation of dimethoate (30 and 150 ppm designated as D1 and D2, respectively) and enhanced UV-B radiation (ambient + supplemental; ambient + 4.0 kJ m(-2) and ambient + 8.0 kJ m(-2), designated as UV-B1 and UV-B2, respectively) induced responses in mung bean seedlings. Seeds of Vigna radiata L. cv. Narendra 1 were surface sterilized, washed thoroughly and soaked for 24 h in sterilized distilled water. Soaked seeds were sown in acid washed sterilized sand filled in plastic trays, and incubated in dark at 26 ± 2 °C for 2 days. The seedlings were grown in growth chamber at 26 ± 2 °C with 12 h photoperiod (350 µmol photons m(-2 )s(-1), PAR) and watered regularly. Six day old seedlings of equal size were gently transferred in 0.2 strength Rorison nutrient medium (pH 6.8) for acclimatization. Thereafter, dimethoate (30 and 150 ppm designated as D1 and D2, respectively) and enhanced UV-B radiation treatments were given. On the 12th day, seedlings of each set were harvested and various parameters related to growth, pigments, photosynthesis, oxidative stress and antioxidant system were analyzed. The D2 dose of dimethoate and UV-B1 and UV-B2 alone and together significantly (P < 0.05) declined growth, photosynthetic pigments and photosynthesis (Fv/Fm and qP except NPQ) which were accompanied by significant decrease in SA level. Similarly, D2 and UV-B also enhanced (P < 0.05) accumulation of reactive oxygen species and concomitantly damaging effects on lipids, proteins and membrane stability were observed. In contrast, in SA-pretreated seedlings damaging impacts of D2, UV-B1 and UV-B2 alone and together were significantly (P < 0.05) alleviated. Besides this, interestingly D1 dose of dimethoate alone had stimulatory effect on growth and it also ameliorated damaging effects of both the doses of UV-B. The activity of superoxide dismutase was

  2. Sulfonation of polyester fabrics by gaseous sulfur oxide activated by UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kordoghli, Bessem [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); Textile Research Laboratory (LRT) - ISET Kasr Hellal, University of Monastir (Tunisia); Khiari, Ramzi, E-mail: khiari_ramzi2000@yahoo.fr [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); LGP2 - Laboratory of Pulp and Paper Science, 461, Rue de la Papeterie - BP 65, 38402 Saint Martin d' Heres Cedex (France); Mhenni, Mohamed Farouk [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); Sakli, Faouzi [Textile Research Laboratory (LRT) - ISET Kasr Hellal, University of Monastir (Tunisia); Belgacem, Mohamed Naceur [LGP2 - Laboratory of Pulp and Paper Science, 461, Rue de la Papeterie - BP 65, 38402 Saint Martin d' Heres Cedex (France)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer In this paper, an original technique was present to improve the hydrophilic properties of polyester fibres. Black-Right-Pointing-Pointer The modification of PET fabric was carried out using gaseous sulfur trioxide activated by UV irradiations. Black-Right-Pointing-Pointer We fully characterized the modified and untreated fabrics. - Abstract: This paper describes an original technique aiming to improve the hydrophilic properties of polyester fibres. In this method, the sulfonation of the aromatic rings is carried out using gaseous sulfur trioxide activated by UV irradiations. Thus, exposing the polyester textile fabric to the UVC light (wavelength around 254 nm) under a stream of sulfur trioxide leads to the fixation of -SO{sub 3}H groups. The amounts of the fixed sulfonate groups depended on the reaction conditions. Evidence of grafting deduced from the measurements of hygroscopic properties was carried out by contact angle measurement, moisture regain as well as by measuring the rate of retention. SEM and FT-IR analysis, DSC and DTA/TGA thermograms showed that no significant modifications have occurred in the bulk of the treated PET fabrics.

  3. Photoluminescence of hexagonal boron nitride: effect of surface oxidation under UV-laser irradiation

    CERN Document Server

    Museur, Luc; Petitet, Jean-Pierre; Michel, Jean Pierre; Kanaev, Andrei V

    2008-01-01

    We report on the UV laser induced fluorescence of hexagonal boron nitride (h-BN) following nanosecond laser irradiation of the surface under vacuum and in different environments of nitrogen gas and ambient air. The observed fluorescence bands are tentatively ascribed to impurity and mono (VN), or multiple (m-VN with m = 2 or 3) nitrogen vacancies. A structured fluorescence band between 300 nm and 350 nm is assigned to impurity-band transition and its complex lineshape is attributed to phonon replicas. An additional band at 340 nm, assigned to VN vacancies on surface, is observed under vacuum and quenched by adsorbed molecular oxygen. UV-irradiation of h-BN under vacuum results in a broad asymmetric fluorescence at ~400 nm assigned to m-VN vacancies; further irradiation breaks more B-N bonds enriching the surface with elemental boron. However, no boron deposit appears under irradiation of samples in ambient atmosphere. This effect is explained by oxygen healing of radiation-induced surface defects. Formation o...

  4. Synthesis of r-GO/TiO{sub 2} composites via the UV-assisted photocatalytic reduction of graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wein-Duo, E-mail: lyc007@mail.ksu.edu.tw [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan, ROC (China); Li, Yan-Ru [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan, ROC (China); Lee, Yi-Chao [Department of Environmental Engineering, Kun Shan University, Tainan 710, Taiwan (China)

    2016-09-01

    Graphical abstract: - Highlights: • rGO/TiO{sub 2} nanocomposites obtained by ultraviolet light catalytic reduction. • An excellent specific capacitance at 226.45 Fg{sup −1} for the rGO/TiO{sub 2} obtained at weight ratio of GO: TiO{sub 2} at 1:2.5. - Abstract: Reduced graphene oxide/TiO{sub 2} (rGO/TiO{sub 2}) composites were synthesized by combined TiO{sub 2} and graphene oxide (GO) under ultraviolet (UV) irradiation. The influences of TiO{sub 2} content on the reduction degree of GO during synthesis of the rGO/TiO{sub 2} composites were investigated and characterized by XRD, Raman, FTIR, SEM and TEM. It is shown that the XRD diffraction peak of 2θ at 10° of the as-prepared GO decreases with the increasing amount of TiO{sub 2} added. When the weight ratio of GO:TiO{sub 2} is 2:1, the XRD diffraction peak of 2θ at 10° of graphene oxide almost disappears. At a GO:TiO{sub 2} of 1:2, the OH functional groups, carboxylic and carbonyl, on the edge of the graphene oxide are effectively removed. Moreover, a morphological study shows the observation of graphene has a corrugated titanium oxide load and intercalation. The as-prepared rGO/TiO{sub 2} obtained from weight ratios of GO: TiO{sub 2} at 1: 2.5 showed a specific capacitance of 226.45 Fg{sup −1} at a scan rate of 10 mV s{sup −1} in 1 M H{sub 2}SO{sub 4} electrolyte solution.

  5. Iohexol degradation in wastewater and urine by UV-based Advanced Oxidation Processes (AOPs): Process modeling and by-products identification.

    Science.gov (United States)

    Giannakis, Stefanos; Jovic, Milica; Gasilova, Natalia; Pastor Gelabert, Miquel; Schindelholz, Simon; Furbringer, Jean-Marie; Girault, Hubert; Pulgarin, César

    2016-07-11

    In this work, an Iodinated Contrast Medium (ICM), Iohexol, was subjected to treatment by 3 Advanced Oxidation Processes (AOPs) (UV, UV/H2O2, UV/H2O2/Fe(2+)). Water, wastewater and urine were spiked with Iohexol, in order to investigate the treatment efficiency of AOPs. A tri-level approach has been deployed to assess the UV-based AOPs efficacy. The treatment was heavily influenced by the UV transmittance and the organics content of the matrix, as dilution and acidification improved the degradation but iron/H2O2 increase only moderately. Furthermore, optimization of the treatment conditions, as well as modeling of the degradation was performed, by step-wise constructed quadratic or product models, and determination of the optimal operational regions was achieved through desirability functions. Finally, global chemical parameters (COD, TOC and UV-Vis absorbance) were followed in parallel with specific analyses to elucidate the degradation process of Iohexol by UV-based AOPs. Through HPLC/MS analysis the degradation pathway and the effects the operational parameters were monitored, thus attributing the pathways the respective modifications. The addition of iron in the UV/H2O2 process inflicted additional pathways beneficial for both Iohexol and organics removal from the matrix.

  6. Study on superoxide and hydroxyl radicals generated in indirect electrochemical oxidation by chemiluminescence and UV-visible spectra

    Institute of Scientific and Technical Information of China (English)

    Zhang Botao; Zhao Lixia; Lin Jinming

    2008-01-01

    The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemiluminescence (CL) and UV-visible spectra in the reactor with a salt bridge that connected the separated chambers. The CL intensity of 4 × 10-9 mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it, which was because of the generation of reactive oxygen species (ROS). The existence of ROS, especially the generation of the superoxide radical, could be affirmed by the fact that the CL intensity of 4 × 10--9 mol/L 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one with bubbling oxygen was about four times that of the intensity without it. However, there was no chemiluminescence on the anode under the same condition. The change in the UV-visible spectra of nitro blue tetrazolium and N,N-dimethyl-4-nitrosoaniline at the cathode chamber affirmed the transformation from oxygen to superoxide and hydroxyl radicals. The mechanism of the superoxide and hydroxyl radical generation and transformation on the cathode was discussed with the help of the experimental results and relative references.

  7. Impact of salinity on organic matter and nitrogen removal from a municipal wastewater RO concentrate using biologically activated carbon coupled with UV/H2O2.

    Science.gov (United States)

    Pradhan, Shovana; Fan, Linhua; Roddick, Felicity A; Shahsavari, Esmaeil; Ball, Andrew S

    2016-05-01

    The concentrate streams generated from reverse osmosis (RO)-based municipal wastewater reclamation processes contain organic substances and nutrients at elevated concentrations, posing environmental and health risks on their disposal to confined receiving environments such as bays. The impact of salinity (TDS at 7, 10 and 16 g/L) of a RO concentrate (ROC) on the treatment efficiency of a biological activated carbon (BAC) system after pre-oxidation with UV/H2O2 was characterised in terms of removal of organic matter and nitrogen species, and the bacterial communities. Organic matter removal was comparable for the ROC over the tested salinity range, with 45-49% of DOC and 70-74% of UVA254 removed by the combined treatment. However, removal in total nitrogen (TN) was considerably higher for the ROC at the high salinity (TDS ∼ 16 mg/L) compared with the low (∼7 g/L) and medium salinity (∼10 g/L). Effective nitrification with high ammonium removal (>90%) was achieved at all salinity levels, whereas greater denitrification (39%) was obtained at high salinity than low (23%) and medium salinity (27%) which might suggest that the bacterial communities contributing to the greater denitrification were more halotolerant. Microbiological characterisation using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and culture based techniques showed that diversified bacterial communities were present in the BAC system as evident from different 16S rDNA. The major bacterial groups residing on the BAC media belonged to Bacillus (Firmicutes), Pseudomonas (γ-Proteobacteria), and Rhodococcus (Actinobacteria) for all salinity levels, confirming that these microbial communities could be responsible for carbon and nitrogen removal at the different salinity levels. This has implications in understanding the effectiveness and robustness of the BAC system over the salinity range of the ROC and so would be useful for optimising the treatment efficiency of

  8. Effect of UV-light illumination on oxide-based electric-double-layer thin-film transistors

    Science.gov (United States)

    Zhou, Jumei; Hu, Yunping

    2017-01-01

    Indium–tin-oxide (ITO)-based thin-film transistors (TFTs) were fabricated using porous SiO2 deposited by plasma-enhanced chemical vapor deposition and Al2O3 deposited by atomic layer deposition as dielectrics. The results showed that the porous SiO2 film exhibited a high electric-double-layer (EDL) capacitance. Devices gated by the EDL dielectric exhibited a high drain current on/off ratio of >106 and a low operation voltage of illuminated by 254 nm UV light, ITO-based EDL TFTs gated by a single SiO2 dielectric displayed weak photo-responses. However, devices gated by a stacked Al2O3/EDL dielectric displayed a high photo responsivity of more than 104 with a gate bias of ‑0.5 V (depletion state).

  9. Mfd is required for rapid recovery of transcription following UV-induced DNA damage but not oxidative DNA damage in Escherichia coli.

    Science.gov (United States)

    Schalow, Brandy J; Courcelle, Charmain T; Courcelle, Justin

    2012-05-01

    Transcription-coupled repair (TCR) is a cellular process by which some forms of DNA damage are repaired more rapidly from transcribed strands of active genes than from nontranscribed strands or the overall genome. In humans, the TCR coupling factor, CSB, plays a critical role in restoring transcription following both UV-induced and oxidative DNA damage. It also contributes indirectly to the global repair of some forms of oxidative DNA damage. The Escherichia coli homolog, Mfd, is similarly required for TCR of UV-induced lesions. However, its contribution to the restoration of transcription and to global repair of oxidative damage has not been examined. Here, we report the first direct study of transcriptional recovery following UV-induced and oxidative DNA damage in E. coli. We observed that mutations in mfd or uvrA reduced the rate that transcription recovered following UV-induced damage. In contrast, no difference was detected in the rate of transcription recovery in mfd, uvrA, fpg, nth, or polB dinB umuDC mutants relative to wild-type cells following oxidative damage. mfd mutants were also fully resistant to hydrogen peroxide (H(2)O(2)) and removed oxidative lesions from the genome at rates comparable to wild-type cells. The results demonstrate that Mfd promotes the rapid recovery of gene expression following UV-induced damage in E. coli. In addition, these findings imply that Mfd may be functionally distinct from its human CSB homolog in that it does not detectably contribute to the recovery of gene expression or global repair following oxidative damage.

  10. Sulfonation of polyester fabrics by gaseous sulfur oxide activated by UV irradiation

    Science.gov (United States)

    Kordoghli, Bessem; Khiari, Ramzi; Mhenni, Mohamed Farouk; Sakli, Faouzi; Belgacem, Mohamed Naceur

    2012-10-01

    This paper describes an original technique aiming to improve the hydrophilic properties of polyester fibres. In this method, the sulfonation of the aromatic rings is carried out using gaseous sulfur trioxide activated by UV irradiations. Thus, exposing the polyester textile fabric to the UVC light (wavelength around 254 nm) under a stream of sulfur trioxide leads to the fixation of sbnd SO3H groups. The amounts of the fixed sulfonate groups depended on the reaction conditions. Evidence of grafting deduced from the measurements of hygroscopic properties was carried out by contact angle measurement, moisture regain as well as by measuring the rate of retention. SEM and FT-IR analysis, DSC and DTA/TGA thermograms showed that no significant modifications have occurred in the bulk of the treated PET fabrics.

  11. Extending human perception of electromagnetic radiation to the UV region through biologically inspired photochromic fuzzy logic (BIPFUL) systems.

    Science.gov (United States)

    Gentili, Pier Luigi; Rightler, Amanda L; Heron, B Mark; Gabbutt, Christopher D

    2016-01-25

    Photochromic fuzzy logic systems have been designed that extend human visual perception into the UV region. The systems are founded on a detailed knowledge of the activation wavelengths and quantum yields of a series of thermally reversible photochromic compounds. By appropriate matching of the photochromic behaviour unique colour signatures are generated in response differing UV activation frequencies.

  12. Poly(ethylene oxide) Solubilization in Reverse Microemulsion: Conductivity and UV-Vis Spectra Studies

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effect of poly (ethylene oxide) (PEO) on the w/o microemulsion is studied. The addition of PEO induces a decrease of attractive interaction between droplets in reverse microemulsion. Due to the absence of interaction between cationic surfactant and neutral polymer, the polymer molecules are forced into the interior of water core, avoiding the interfacial region.

  13. UV- and salinity-induced oxidative effects in the marine diatom Cylindrotheca closterium during simulated emersion

    NARCIS (Netherlands)

    Rijstenbil, J.W.

    2005-01-01

    The diatom Cylindrotheca closterium was exposed to transient light- and osmotic conditions as occur during its tidal emersion. The objective was to analyze how this simulated emersion contributes to the production of active oxygen species (AOS) and via this, to oxidative cell damage. Light- and sali

  14. An effective method of UV-oxidation of dissolved organic carbon in natural waters for radiocarbon analysis by accelerator mass spectrometry

    Science.gov (United States)

    Xue, Yuejun; Ge, Tiantian; Wang, Xuchen

    2015-12-01

    Radiocarbon (14C) measurement of dissolved organic carbon (DOC) is a very powerful tool to study the sources, transformation and cycling of carbon in the ocean. The technique, however, remains great challenges for complete and successful oxidation of sufficient DOC with low blanks for high precision carbon isotopic ratio analysis, largely due to the overwhelming proportion of salts and low DOC concentrations in the ocean. In this paper, we report an effective UV-Oxidation method for oxidizing DOC in natural waters for radiocarbon analysis by accelerator mass spectrometry (AMS). The UV-oxidation system and method show 95%±4% oxidation efficiency and high reproducibility for DOC in both river and seawater samples. The blanks associated with the method was also low (about 3 µg C) that is critical for 14C analysis. As a great advantage of the method, multiple water samples can be oxidized at the same time so it reduces the sample processing time substantially compared with other UV-oxidation method currently being used in other laboratories. We have used the system and method for 14C studies of DOC in rivers, estuaries, and oceanic environments and have received promise results.

  15. Decision criteria for the selection of wet oxidation and conventional biological treatment.

    Science.gov (United States)

    Collado, Sergio; Laca, Adriana; Diaz, Mario

    2012-07-15

    The suitability of wet oxidation or biological treatments for the degradation of industrial wastewaters is here discussed. Advantages of these operations, either singly or in combination, are discussed on the basis of previous experimental results from laboratory and industry. Decision diagrams for the selection of conventional biological treatment, wet oxidation or a combination of both techniques are suggested according to the type of pollutant, its concentration and the wastewater flow rate.

  16. Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous Fenton oxidation and biological process.

    Science.gov (United States)

    Xu, Peng; Han, Hongjun; Zhuang, Haifeng; Hou, Baolin; Jia, Shengyong; Xu, Chunyan; Wang, Dexin

    2015-04-01

    Laboratorial scale experiments were conducted in order to investigate a novel system integrating heterogeneous Fenton oxidation (HFO) with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process on advanced treatment of biologically pretreated coal gasification wastewater (CGW). The results indicated that HFO with the prepared catalyst (FeOx/SBAC, sewage sludge based activated carbon (SBAC) which loaded Fe oxides) played a key role in eliminating COD and COLOR as well as in improving the biodegradability of raw wastewater. The surface reaction and hydroxyl radicals (OH) oxidation were the mechanisms for FeOx/SBAC catalytic reaction. Compared with ANMBBR-BAF process, the integrated system was more effective in abating COD, BOD5, total phenols (TPs), total nitrogen (TN) and COLOR and could shorten the retention time. Therefore, the integrated system was a promising technology for engineering applications.

  17. Treatment of Phenol- containing Wastewater by UV/Fenton Oxidation- coagulation Process%UV/Fenton氧化-混凝联合工艺处理含酚废水

    Institute of Scientific and Technical Information of China (English)

    刘琼玉; 李太友; 陈化琼; 于丹丹

    2004-01-01

    采用UV/Fenton氧化-混凝联合工艺对模拟苯酚废水进行处理,探讨了 UV/Fenton预氧化程度和混凝处理条件对模拟苯酚废水处理效果的影响.结果表明,采用混凝处理,COD去除率仅为14.1%;当UV/Fenton预氧化处理过程中H2O2的质量浓度为150~300mg/L时,废水的混凝性能可提高1.5倍以上;当H2O2质量浓度为450 mg/L、光反应时间为30 min时,采用UV/Fenton氧化-混凝工艺联合处理后COD去除率达82.7%.苯酚废水采用UV/Fenton预氧化处理后,进行混凝处理过程的适宜pH为6.5,混凝剂Fe3+的适宜质量浓度为500 mg/L.

  18. Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions.

    Science.gov (United States)

    de Vet, W W J M; Dinkla, I J T; Rietveld, L C; van Loosdrecht, M C M

    2011-11-01

    Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation.

  19. Fluorescent biological aerosol particle concentrations and size distributions measured with an ultraviolet aerodynamic particle sizer (UV-APS) in Central Europe

    OpenAIRE

    J. A. Huffman; Treutlein, B.; U. Pöschl

    2009-01-01

    Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure ...

  20. Effect of advanced oxidation on N-nitrosodimethylamine (NDMA) formation and microbial ecology during pilot-scale biological activated carbon filtration.

    Science.gov (United States)

    Li, Dong; Stanford, Ben; Dickenson, Eric; Khunjar, Wendell O; Homme, Carissa L; Rosenfeldt, Erik J; Sharp, Jonathan O

    2017-04-15

    Water treatment combining advanced oxidative processes with subsequent exposure to biological activated carbon (BAC) holds promise for the attenuation of recalcitrant pollutants. Here we contrast oxidation and subsequent biofiltration of treated wastewater effluent employing either ozone or UV/H2O2 followed by BAC during pilot-scale implementation. Both treatment trains largely met target water quality goals by facilitating the removal of a suite of trace organics and bulk water parameters. N-nitrosodimethylamine (NDMA) formation was observed in ozone fed BAC columns during biofiltration and to a lesser extent in UV/H2O2 fed columns and was most pronounced at 20 min of empty bed contact time (EBCT) when compared to shorter EBCTs evaluated. While microbial populations were highly similar in the upper reaches, deeper samples revealed a divergence within and between BAC filtration systems where EBCT was identified to be a significant environmental predictor for shifts in microbial populations. The abundance of Nitrospira in the top samples of both columns provides an explanation for the oxidation of nitrite and corresponding increases in nitrate concentrations during BAC transit and support interplay between nitrogen cycling with nitrosamine formation. The results of this study demonstrate that pretreatments using ozone versus UV/H2O2 impart modest differences to the overall BAC microbial population structural and functional attributes, and further highlight the need to evaluate NDMA formation prior to full-scale implementation of BAC in potable reuse applications.

  1. Effects of UV/Ag-TiO2/O3 advanced oxidation on unicellular green alga Dunaliella salina: Implications for removal of invasive species from ballast water

    Institute of Scientific and Technical Information of China (English)

    Donghai Wu; Hong You; Jiaxuan Du; Chuan Chen; Darui Jin

    2011-01-01

    The UV/Ag-TiO2/O3 process was investigated for ballast water treatment using Dunaliella salina as an indicator.Inactivation curves were obtained, and the toxicity of effluent was determined.Compared with individual unit processes using ozone or UV/Ag-TiO2, the inactivation efficiency of D.salina by the combined UV/Ag-TiO2/O3 process was enhanced.The presence of ozone caused an immediate decrease in chlorophyll a (chi-a) concentration.Inactivation efficiency and chl-a removal efficiency were positively correlated with ozone dose and ultraviolet intensity.The initial total residual oxidant (TRO) concentration of effluent increased with increasing ozone dose, and persistence of TRO resulted in an extended period of toxicity.The results suggest that UV/Ag-Ti02/03 has potential for ballast water treatment.

  2. New Conjugated Benzothiazole-N-oxides: Synthesis and Biological Activity

    Directory of Open Access Journals (Sweden)

    Pavlína Foltínová

    2009-12-01

    Full Text Available Eleven new 2-styrylbenzothiazole-N-oxides have been prepared by aldol – type condensation reactions between 2-methylbenzothiazole–N-oxide and para-substituted benzaldehydes. Compounds with cyclic amino substituents showed typical push-pull molecule properties. Four compounds were tested against various bacterial strains as well as the protozoan Euglena gracilis as model microorganisms. Unlike previously prepared analogous benzothiazolium salts, only weak activity was recorded.

  3. pH effect on decolorization of raw textile wastewater polluted with reactive dyes by advanced oxidation with uv/h2o2

    NARCIS (Netherlands)

    Racyte, J.; Rimeika, M.; Bruning, H.

    2009-01-01

    The effectiveness of the advanced oxidation process (UV/H2O2) in decolorizing real textile wastewater polluted with commercial reactive dyes - Reactive Yellow 84 and Reactive Red 141 was investigated. All the experiments were performed in a lab-scale reactor with the original high pH of the wastewat

  4. Nanocrystalline semiconductor doped rare earth oxide for the photocatalytic degradation studies on Acid Blue 113: A di-azo compound under UV slurry photoreactor.

    Science.gov (United States)

    Suganya Josephine, G A; Mary Nisha, U; Meenakshi, G; Sivasamy, A

    2015-11-01

    Preventive measures for the control of environmental pollution and its remediation has received much interest in recent years due to the world-wide increase in the contamination of water bodies. Contributions of these harmful effluents are caused by the leather processing, pharmaceutical, cosmetic, textile, agricultural and other chemical industries. Nowadays, advanced oxidation processes considered to be better option for the complete destruction of organic contaminants in water and wastewater. Acid Blue 113 is a most widely used di-azo compound in leather, textile, dying and food industry as a color rending compound. In the present study, we have reported the photo catalytic degradation of Acid Blue 113 using a nanocrystalline semiconductor doped rare earth oxide as a photo catalyst under UV light irradiation. The photocatalyst was prepared by a simple precipitation technique and were characterized by XRD, FT-IR, UV-DRS and FE-SEM analysis. The experimental results proved that the prepared photo catalyst was nanocrystalline and highly active in the UV region. The UV-DRS results showed the band gap energy was 3.15eV for the prepared photo catalyst. The photodegradation efficiency was analyzed by various experimental parameters such as pH, catalyst dosage, variation of substrate concentration and effect of electrolyte addition. The photo degradation process followed a pseudo first order kinetics and was continuously monitored by UV-visible spectrophotometer. The experimental results proved the efficacy of the nanocrystalline zinc oxide doped dysprosium oxide which are highly active under UV light irradiations. It is also suggested that the prepared material would find wider applications in environmental remediation technologies to remove the carcinogenic and toxic moieties present in the industrial effluents.

  5. Biodegradability enhancement of a pesticide-containing bio-treated wastewater using a solar photo-Fenton treatment step followed by a biological oxidation process.

    Science.gov (United States)

    Vilar, Vítor J P; Moreira, Francisca C; Ferreira, Ana C C; Sousa, M A; Gonçalves, C; Alpendurada, M F; Boaventura, Rui A R

    2012-10-01

    This work proposes an efficient combined treatment for the decontamination of a pesticide-containing wastewater resulting from phytopharmaceutical plastic containers washing, presenting a moderate organic load (COD=1662-1960 mg O₂ L⁻¹; DOC=513-696 mg C L⁻¹), with a high biodegradable organic carbon fraction (81%; BOD₅=1350-1600 mg O₂ L⁻¹) and a remaining recalcitrant organic carbon mainly due to pesticides. Nineteen pesticides were quantified by LC-MS/MS at concentrations between 0.02 and 45 mg L⁻¹ (14-19% of DOC). The decontamination strategy involved a sequential three-step treatment: (a) biological oxidation process, leading to almost complete removal of the biodegradable organic carbon fraction; (b) solar photo-Fenton process using CPCs, enhancing the bio-treated wastewater biodegradability, mainly due to pesticides degradation into low-molecular-weight carboxylate anions; (c) and a final polishing step to remove the residual biodegradable organic carbon, using a biological oxidation process. Treatment performance was evaluated in terms of mineralization degree (DOC), pesticides content (LC-MS/MS), inorganic ions and low-molecular-weight carboxylate anions (IC) concentrations. The estimated phototreatment energy necessary to reach a biodegradable wastewater, considering pesticides and low-molecular-weight carboxylate anions concentrations, Zahn-Wellens test and BOD₅/COD ratio, was only 2.3 kJ(UV) L⁻¹ (45 min of photo-Fenton at a constant solar UV power of 30 W m⁻²), consuming 16 mM of H₂O₂, which pointed to 52% mineralization and an abatement higher than 86% for 18 pesticides. The biological oxidation/solar photo-Fenton/biological oxidation treatment system achieved pesticide removals below the respective detection limits and 79% mineralization, leading to a COD value lower than 150 mg O₂ L⁻¹, which is in agreement with Portuguese discharge limits regarding water bodies.

  6. Possible domestication of uranium oxides using biological assistance reduction

    Directory of Open Access Journals (Sweden)

    Slah Hidouri

    2017-01-01

    Full Text Available Uranium has been defined in material research engineering field as one of the most energetic radioactive elements in the entire Mendeleev periodic table. The manipulation of uranium needs higher theories and sophisticated apparatus even in nuclear energy extraction or in many other chemical applications. Above the nuclear exploitation level, the chemical conventional approaches used, require a higher temperature and pressure to control the destination of ionic form. However, it has been discovered later that at biological scale, the manipulation of this actinide is possible under friendly conditions. The review summarizes the relevant properties of uranium element and a brief characterization of nanoparticles, based on some structural techniques. These techniques reveal the common link between chemical approaches and biological assistance in nanoparticles. Also, those biological entities have been able to get it after reduction. Uranium is known for its ability to destroy ductile materials. So, if biological cell can really reduce uranium, then how does it work?

  7. High quality reduced graphene oxide flakes by fast kinetically controlled and clean indirect UV-induced radical reduction

    Science.gov (United States)

    Flyunt, Roman; Knolle, Wolfgang; Kahnt, Axel; Halbig, Christian E.; Lotnyk, Andriy; Häupl, Tilmann; Prager, Andrea; Eigler, Siegfried; Abel, Bernd

    2016-03-01

    This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the GO is not excited directly. While the direct photoexcitation of aqueous GO (when GO is the only light-absorbing component) takes several hours of reaction time at ambient temperature (4 h) leading only to a partial GO reduction, the addition of small amounts of isopropanol and acetone (2% and 1%) leads to a dramatically shortened reaction time by more than two orders of magnitude (2 min) and a very efficient and soft reduction of graphene oxide. This method avoids the formation of non-volatile species and in turn contamination of the produced rGO and it is based on the highly efficient generation of reducing carbon centered isopropanol radicals via the reaction of triplet acetone with isopropanol. While the direct photolysis of GO dispersions easily leads to degradation of the carbon lattice of GO and thus to a relatively low electric conductivity of the films of flakes, our indirect photoreduction of GO instead largely avoids the formation of defects, keeping the carbon lattice intact. Mechanisms of the direct and indirect photoreduction of GO have been elucidated and compared. Raman spectroscopy, XPS and conductivity measurements prove the efficiency of the indirect photoreduction in comparison with the state-of-the-art reduction method for GO (hydriodic acid/trifluoroacetic acid). The rapid reduction times and water solvent containing only small amounts of isopropanol and acetone may allow easy process up-scaling for technical applications and low-energy consumption.This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the

  8. UV light emitting transparent conducting tin-doped indium oxide (ITO) nanowires.

    Science.gov (United States)

    Gao, J; Chen, R; Li, D H; Jiang, L; Ye, J C; Ma, X C; Chen, X D; Xiong, Q H; Sun, H D; Wu, T

    2011-05-13

    Multifunctional single crystalline tin-doped indium oxide (ITO) nanowires with tuned Sn doping levels are synthesized via a vapor transport method. The Sn concentration in the nanowires can reach 6.4 at.% at a synthesis temperature of 840 °C, significantly exceeding the Sn solubility in ITO bulks grown at comparable temperatures, which we attribute to the unique feature of the vapor-liquid-solid growth. As a promising transparent conducting oxide nanomaterial, layers of these ITO nanowires exhibit a sheet resistance as low as 6.4 Ω/[Symbol: see text] and measurements on individual nanowires give a resistivity of 2.4 × 10(-4) Ω cm with an electron density up to 2.6 × 10(20) cm(-3), while the optical transmittance in the visible regime can reach ∼ 80%. Under the ultraviolet excitation the ITO nanowire samples emit blue light, which can be ascribed to transitions related to defect levels. Furthermore, a room temperature ultraviolet light emission is observed in these ITO nanowires for the first time, and the exciton-related radiative process is identified by using temperature-dependent photoluminescence measurements.

  9. Degradation of a textile reactive azo dye by a combined biological-photocatalytic process: Candida tropicalis Jks2 -Tio2/Uv

    Directory of Open Access Journals (Sweden)

    Narjes Jafari

    2012-12-01

    Full Text Available In the present study, the decolorization and degradation of Reactive Black 5 (RB5 azo dye was investigated by biological, photocatalytic (UV/TiO2 and combined processes.Application of Candida tropicalis JKS2 in treatment of the synthetic medium containing RB5 indicated complete decolorization of the dye with 200 mg/L in less than 24 h. Degradation ofthe aromatic rings, resulting from the destruction of the dye, did not occur during the biological treatment. Mineralization of 50 mg/L RB5 solution was obtained after 80 min by photocatalytic process (in presence of 0.2 g/L TiO2. COD (chemical oxygen demand wasnot detectable after complete decolorization of 50 mg/L RB5 solution. However,photocatalytic process was not effective in the removal of the dye at high concentrations (≥200 mg/L. With 200 mg/L concentration, 74.9% of decolorization was achieved after 4 hillumination under photocatalytic process and the absorbance peak in UV region (attributed to aromatic rings was not completely removed. A two-step treatment process, namely,biological treatment by yeast followed by photocatalytic degradation, was also assessed. In the combined process (with 200 mg/L RB5, absorbance peak in UV region significantly disappeared after 2 h illumination and about 60 % COD removal was achieved in the biological step. It is suggested that the combined process is more effective than the biological and photocatalytic treatments in the remediation of aromatic rings.

  10. Degradation of a textile reactive azo dye by a combined biological-photocatalytic process: Candida tropicalis Jks2 -Tio2/Uv

    Directory of Open Access Journals (Sweden)

    Jafari Narjes

    2012-12-01

    Full Text Available Abstract In the present study, the decolorization and degradation of Reactive Black 5 (RB5 azo dye was investigated by biological, photocatalytic (UV/TiO2 and combined processes. Application of Candida tropicalis JKS2 in treatment of the synthetic medium containing RB5 indicated complete decolorization of the dye with 200 mg/L in less than 24 h. Degradation of the aromatic rings, resulting from the destruction of the dye, did not occur during the biological treatment. Mineralization of 50 mg/L RB5 solution was obtained after 80 min by photocatalytic process (in presence of 0.2 g/L TiO2. COD (chemical oxygen demand was not detectable after complete decolorization of 50 mg/L RB5 solution. However, photocatalytic process was not effective in the removal of the dye at high concentrations (≥200 mg/L. With 200 mg/L concentration, 74.9% of decolorization was achieved after 4 h illumination under photocatalytic process and the absorbance peak in UV region (attributed to aromatic rings was not completely removed. A two-step treatment process, namely, biological treatment by yeast followed by photocatalytic degradation, was also assessed. In the combined process (with 200 mg/L RB5, absorbance peak in UV region significantly disappeared after 2 h illumination and about 60% COD removal was achieved in the biological step. It is suggested that the combined process is more effective than the biological and photocatalytic treatments in the remediation of aromatic rings.

  11. Application of a molecular biology concept for the detection of DNA damage and repair during UV disinfection.

    Science.gov (United States)

    Süss, Jacqueline; Volz, Sabrina; Obst, Ursula; Schwartz, Thomas

    2009-08-01

    As nucleic acids are major targets in bacteria during standardised UV disinfection (254 nm), inactivation rates also depend on bacterial DNA repair. Due to UV-related DNA modifications, PCR-based approaches allow for a direct detection of DNA damage and repair during UV disinfection. By applying different primer sets, the correlation between amplicon length and PCR amplification became obvious. The longer the targeted DNA fragment was, the more UV-induced DNA lesions inhibited the PCR. Regeneration of Pseudomonas aeruginosa, Enterococcus faecium, and complex wastewater communities was recorded over a time period of 66 h. While phases of intensive repair and proliferation were found for P. aeruginosa, no DNA repair was detected by qPCR in E. faecium. Cultivation experiments verified these results. Despite high UV mediated inactivation rates original wastewater bacteria seem to express an enhanced robustness against irradiation. Regeneration of dominant and proliferation of low-abundant, probably UV-resistant species contributed to a strong post-irradiation recovery accompanied by a selection for beta-Proteobacteria.

  12. Study of reactive blue 171 dye degradation in hybrid system of UV/H2O2 & SBAR

    Directory of Open Access Journals (Sweden)

    leila Moradi Pasand

    2014-03-01

    Conclusion: According to the results, because of complexity of dye structure, biological system was not able to remove the dye as efficient as hybrid system of advanced oxidation processes UV/H2O2 with SBAR.

  13. Co-oxidation of carcinogenic polycyclic aromatic hydrocarbons with some biologically active compounds (BAC)

    Energy Technology Data Exchange (ETDEWEB)

    Gubergrits, M.Y.

    1978-09-01

    Oxidation of benzo(a)pyrene (BP) initiated by UV or gamma irradiation was promoted by benz(a)anthracene and 7,12-dimethylbenz(a)anthracene (DMBA) and inhibited by pyrene, dibenz(a,c)anthracene, and asymmetric benz(a)antharacene. The effects of these BAC commonly occurring together with BP in industrial wastes, increased with their concentrations. Phenol and 3-methylcholanthrene strongly promoted BP oxidation when present at low concentrations and inhibited it at high concentrations. Consistent promoting effect was also observed in BP co-oxidation with adipic acid, ..cap alpha..-naphthoflavon, and vitamin E, whereas succinic, azelaic, ferulic, gallic, and chlorogenic acids, rutin, and vitamin C acted as inhibitors. Most saturated dicarboxylic acids studied did not affect BP oxidation at 1:1 acid-BP molar ratio. The kinetics of 7,12-DMBA photooxidation inhibition by some metabolic intermediates, e.g., DMBA endo-peroxide, were also studied.

  14. Differential biologic effects of CPD and 6-4PP UV-induced DNA damage on the induction of apoptosis and cell-cycle arrest

    Directory of Open Access Journals (Sweden)

    Yasui Akira

    2005-10-01

    Full Text Available Abstract Background UV-induced damage can induce apoptosis or trigger DNA repair mechanisms. Minor DNA damage is thought to halt the cell cycle to allow effective repair, while more severe damage can induce an apoptotic program. Of the two major types of UV-induced DNA lesions, it has been reported that repair of CPD, but not 6-4PP, abrogates mutation. To address whether the two major forms of UV-induced DNA damage, can induce differential biological effects, NER-deficient cells containing either CPD photolyase or 6-4 PP photolyase were exposed to UV and examined for alterations in cell cycle and apoptosis. In addition, pTpT, a molecular mimic of CPD was tested in vitro and in vivo for the ability to induce cell death and cell cycle alterations. Methods NER-deficient XPA cells were stably transfected with CPD-photolyase or 6-4PP photolyase to specifically repair only CPD or only 6-4PP. After 300 J/m2 UVB exposure photoreactivation light (PR, UVA 60 kJ/m2 was provided for photolyase activation and DNA repair. Apoptosis was monitored 24 hours later by flow cytometric analysis of DNA content, using sub-G1 staining to indicate apoptotic cells. To confirm the effects observed with CPD lesions, the molecular mimic of CPD, pTpT, was also tested in vitro and in vivo for its effect on cell cycle and apoptosis. Results The specific repair of 6-4PP lesions after UVB exposure resulted in a dramatic reduction in apoptosis. These findings suggested that 6-4PP lesions may be the primary inducer of UVB-induced apoptosis. Repair of CPD lesions (despite their relative abundance in the UV-damaged cell had little effect on the induction of apoptosis. Supporting these findings, the molecular mimic of CPD, (dinucleotide pTpT could mimic the effects of UVB on cell cycle arrest, but were ineffective to induce apoptosis. Conclusion The primary response of the cell to UV-induced 6-4PP lesions is to trigger an apoptotic program whereas the response of the cell to CPD

  15. Biological reduction of graphene oxide using plant leaf extracts.

    Science.gov (United States)

    Lee, Geummi; Kim, Beom Soo

    2014-01-01

    Two-dimensional graphene has attracted significant attention due to its unique mechanical, electrical, thermal, and optical properties. Most commonly employed methods to chemically reduce graphene oxide to graphene use hydrazine or its derivatives as the reducing agent. However, they are highly hazardous and explosive. Various phytochemicals obtained from different natural sources such as leaves and peels of a plant are used as reducing agents in the preparation of different gold, silver, copper, and platinum nanoparticles. In this study, seven plant leaf extracts (Cherry, Magnolia, Platanus, Persimmon, Pine, Maple, and Ginkgo) were compared for their abilities to reduce graphene oxide. The optimized reaction conditions for the reduction of graphene oxide were determined as follows. Type of plant: Cherry (Prunus serrulata), reaction time: 12 h, composition of the reaction mixture: 16.7% v/v of plant leaf extract in total suspension, and temperature: 95°C. The degree of reduction caused by Cherry leaf extract was analyzed by elemental analysis and X-ray photoelectron spectroscopy. The reduction of graphene oxide was also confirmed by ultraviolet-visible spectroscopy, Fourier transform-infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, and thermogravimetric analysis.

  16. The influence of the UV irradiation intensity on photocatalytic activity of ZnAl layered double hydroxides and derived mixed oxides

    Directory of Open Access Journals (Sweden)

    Hadnađev-Kostić Milica S.

    2012-01-01

    Full Text Available Layered double hydroxides (LDHs have been studied to a great extent as environmental-friendly complex materials that can be used as photocatalysts or photocatalyst supports. ZnAl layered double hydroxides and their derived mixed oxides were chosen for the investigation of photocatalytic performances in correlation with the UV intensities measured in the South Pannonia region. Low supersaturation coprecipitation method was used for the ZnAl LDH synthesis. For the characterization of LDH and thermal treated samples powder X-ray diffraction (XRD, scanning electron microscopy (SEM, electron dispersive spectroscopy (EDS, nitrogen adsorption-desorption were used. The decomposition of azodye, methylene blue was chosen as photocatalytic test reaction. The study showed that the ZnAl mixed oxide obtained by thermal decomposition of ZnAl LDH has stable activity in the broader UV light irradiation range characterizing the selected region. Photocatalytic activity could be mainly attributed to the ZnO phase, detected both in LDH and thermally treated samples. The study showed that the ZnAl mixed oxide obtained by the calcination of ZnAl LDH has a stable activity within the measured UV light irradiation range; whereas the parent ZnAl LDH catalyst did not perform satisfactory when low UV irradiation intensity is implied.

  17. Abatement of Polychoro-1,3-butadienes in Aqueous Solution by Ozone, UV Photolysis, and Advanced Oxidation Processes (O3/H2O2 and UV/H2O2).

    Science.gov (United States)

    Lee, Minju; Merle, Tony; Rentsch, Daniel; Canonica, Silvio; von Gunten, Urs

    2017-01-03

    The abatement of 9 polychloro-1,3-butadienes (CBDs) in aqueous solution by ozone, UV-C(254 nm) photolysis, and the corresponding advanced oxidation processes (AOPs) (i.e., O3/H2O2 and UV/H2O2) was investigated. The following parameters were determined for 9 CBDs: second-order rate constants for the reactions of CBDs with ozone (kO3) (50% at specific ozone doses of 0.5 gO3/gDOC to ∼100% at ≥1.0 gO3/gDOC) were achieved for tetra-CBDs followed by (Z)-1,1,2,3,4-penta-CBD and hexa-CBD. This is consistent with the magnitude of the determined kO3 and k(•)OH. The formation of bromate, a potentially carcinogenic ozonation byproduct, could be significantly reduced by addition of H2O2. For a typical UV disinfection dose (400 J/m(2)), various extents of phototransformations (10-90%) could be achieved. However, the efficient formation of photoisomers from CBDs with E/Z configuration must be taken into account because of their potential residual toxicity. Under UV-C(254 nm) photolysis conditions, no significant effect of H2O2 addition on CBDs abatement was observed due to an efficient direct phototransformation of CBDs.

  18. Vacuum UV photolysis of CO 2. Rare-gas oxide formation in matrices

    Science.gov (United States)

    Fournier, J.; Mohammed, H. H.; Deson, J.; Maillard, D.

    1982-08-01

    In this paper, we report experimental results obtained upon photolysis of CO 2 trapped at low concentrations (0.1%) in neon, argon and krypton matrices. The mixture are photolysed using a xenon resonance lamp emitting photons at 8.4 eV. Only in a neon matrix does the photolysis of CO 2 lead to O( 1D) → O( 3P) emission. Furthermore, oxygen atoms are shown to diffuse at all temperatures in a neon matrix (as detected by molecular oxygen emission), whereas in the other matrices this occurs only when the sample is warmed even though irradiation is performed at high temperature. In argon and krypton matrices, O( 1S) → O( 1D) emission is observed even though there is not enough energy to form an O( 1S) atom in a primary photodecomposition process. This suggests that O( 1D) becomes bound to argon or krypton atoms as a stable rare-gas oxide RGO excimer, which is subsequently excited and photolysed by 8.4 eV photons. These observed features are explained using a model for the interaction between oxygen ( 3P, 1D, 1S) and rare-gas atoms ( 1S) which had previously been proposed to account for the emission spectra of oxygen atoms observed during photolysis of oxygenated compounds.

  19. UV/chlorine as an advanced oxidation process for the degradation of benzalkonium chloride: Synergistic effect, transformation products and toxicity evaluation.

    Science.gov (United States)

    Huang, Nan; Wang, Ting; Wang, Wen-Long; Wu, Qian-Yuan; Li, Ang; Hu, Hong-Ying

    2017-05-01

    Benzalkonium chlorides (BACs), as typical cationic surfactants and biocides widely applied in household and industrial products, have been frequently detected as micropollutants in many aquatic environments. In this study, the combination of UV irradiation and chlorine (UV/chlorine), a newly interested advanced oxidation process, was used to degrade dodecylbenzyldimethylammonium chloride (DDBAC). UV/chlorine showed synergistic effects on DDBAC degradation comparing to UV irradiation or chlorination alone. Radical quenching experiments indicated that degradation of DDBAC by UV/chlorine involved both UV photolysis and radical species oxidation, which accounted for 48.4% and 51.6%, respectively. Chlorine dosage and pH are essential parameters affecting the treatment efficiency of UV/chlorine. The pseudo first order rate constant (kobs, DDBAC) increased from 0.046 min(-1) to 0.123 min(-1) in response to chlorine dosage at 0-150 mg/L, and the degradation percentage of DDBAC within 12 min decreased from 81.4% to 56.6% at pH 3.6-9.5. Five main intermediates were identified and semi-quantified using HPLC-MS/MS and a possible degradation pathway was proposed. The degradation mechanisms of DDBAC by UV/chlorine included cleavage of the benzyl-nitrogen bond and hydrogen abstraction of the alkyl chain. Trichloromethane (TCM), chloral hydrate (CH), trichloropropanone (TCP), dichloropropanone (DCP) and dichloroacetonitrile (DCAN) were detected using GC-ECD. The formation of chlorinated products increased rapidly initially, then decreased (TCM, TCP, DCP and DCAN) or remained stable (CH) with extended treatment. The actual formation of TCM peaked at 30 min (50.3 μg/L), while other chlorinated products did not exceed 10 μg/L throughout the process. Based on the luminescent bacterial assay, DDBAC solution underwent almost complete detoxification subjected to UV/chlorine treatment for 120 min, which is more effective than UV irradiation or chlorination alone.

  20. Laboratory studies of biological effects of sulfur oxides

    Energy Technology Data Exchange (ETDEWEB)

    Dalbey, W. E.

    1979-01-01

    Selected results from exposures of laboratory animals to airborne sulfur oxides were briefly summarized. The main observation during acute exposures was reflex bronchoconstriction and a resultant increase in pulmonary resistance. The increase in resistance due to sulfur dioxide (SO/sub 2/) was potentiated by simultaneous exposure to aerosols under conditions which would increase the transfer of sulfur oxides into the respiratory tract and promote transformation to a higher oxidation state, especially one that is acid. Sulfate aerosols, particularly sulfuric acid aerosols, were more potent than SO/sub 2/ in causing bronchoconstriction. Chronic exposure to high concentrations (400 to 650 ppM) of SO/sub 2/ resulted in experimental bronchitis in several species. Longterm exposure to more realistic concentrations of SO/sub 2/ produced little or no changes in respiratory function or morphology. Significant alterations in both pulmonary function and morphology have been reported after chronic exposure to sulfuric acid aerosols. Recent data indicate that changes in the lung may progress after cessation of such exposures.

  1. UV-Assisted Alcohol Sensors using Gallium Nitride Nanowires Functionalized with Zinc Oxide and Tin Dioxide Nanoparticles

    Science.gov (United States)

    Bajpai, Ritu

    The motivation behind this work has been to address two of the most challenging issues posed to semiconductor gas sensors--- tuning the device selectivity and sensitivity to a wide variety of gases. In a chemiresistor type nanowire sensor, the sensitivity and selectivity depend on the interaction of different chemical analytes with the nanowire surface. Constrained by the surface properties of the nanowire material, most nanowire sensors can detect only specific type of analytes. In order to make a nano-sensor array for a wide range of analytes, there is a need to tune the device sensitivity and selectivity towards different chemicals. Employing the inherent advantages of nanostructure based sensing such as large surface area, miniature size, low power consumption, and nmol/mol (ppb) sensitivity, an attempt has been made to propose a device with tunable selectivity and sensitivity. The idea proposed in this work is to functionalize GaN nanowires which have relatively inactive surface properties (i.e., with no chemiresistive sensitivity to different classes of organic vapors), with analyte dependent active metal oxides. The selectivity of the sensor devices is controlled independent of the surface properties of the nanowire itself. It is the surface properties of the functionalizing metal oxides which determine the selectivity of these sensors. Further facilitated by the proposed fabrication technique, these sensors can be easily tuned to detect different gases. The prototype developed in this work is that of a UV assisted alcohol sensor using GaN nanowires functionalized with ZnO and SnO2 nanoparticles. As opposed to the widely demonstrated metal oxide based sensors assisted by elevated temperature, the operation of photoconductive semiconductor sensor devices such as those fabricated in this work, can also be assisted by UV illumination at room temperature. Temperature assisted sensing requires an integrated on-chip heater, which could impose constraints on the

  2. Ultrasensitive self-powered large area planar GaN UV-photodetector using reduced graphene oxide electrodes

    Science.gov (United States)

    Prakash, Nisha; Singh, Manjri; Kumar, Gaurav; Barvat, Arun; Anand, Kritika; Pal, Prabir; Singh, Surinder P.; Khanna, Suraj P.

    2016-12-01

    A simplistic design of a self-powered UV-photodetector device based on hybrid reduced-graphene-oxide (r-GO)/gallium nitride (GaN) is demonstrated. Under zero bias, the fabricated hybrid photodetector shows a photosensivity of ˜85% while the ohmic contact GaN photodetector with an identical device structure exhibits only ˜5.3% photosensivity at 350 nm illumination (18 μW/cm2). The responsivity and detectivity of the hybrid device were found to be 1.54 mA/W and 1.45 × 1010 Jones (cm Hz½ W-1), respectively, at zero bias with fast response (60 ms), recovery time (267 ms), and excellent repeatability. Power density-dependent responsivity and detectivity revealed ultrasensitive behaviour under low light conditions. The source of the observed self-powered effect in the hybrid photodetector is attributed to the depletion region formed at the r-GO and GaN quasi-ohmic interface.

  3. Self-Powered UV-Near Infrared Photodetector Based on Reduced Graphene Oxide/n-Si Vertical Heterojunction.

    Science.gov (United States)

    Li, Guanghui; Liu, Lin; Wu, Guan; Chen, Wei; Qin, Sujie; Wang, Yi; Zhang, Ting

    2016-09-01

    A novel self-powered photodetector based on reduced graphene oxide (rGO)/n-Si p-n vertical heterojunction with high sensitivity and fast response time is presented. The photodetector contains a p-n vertical heterojunction between a drop-casted rGO thin film and n-Si. Contacts between the semiconductor layer (rGO, n-Si) and source-drain Ti/Au electrodes allow efficient transfer of photogenerated charge carriers. The self-powered UV-near infrared photodetector shows high sensitivity toward a spectrum of light from 365 to 1200 nm. Under the 600 nm illumination (0.81 mW cm(-2) ), the device has a photoresponsivity of 1.52 A W(-1) , with fast response and recover time (2 ms and 3.7 ms), and the ON/OFF ratios exceed 10(4) when the power density reaches ≈2.5 mW cm(-2) . The high photoresponse primarily arises from the built-in electric field formed at the interface of n-Si and rGO film. The effect of rGO thickness, rGO reduction level, and layout of rGO/n-Si effective contact area on device performance are also systematically investigated.

  4. The oxidation of PET track-etched membranes by hydrogen peroxide as an effective method to increase efficiency of UV-induced graft polymerization

    Directory of Open Access Journals (Sweden)

    Il'ya Korolkov

    2015-12-01

    Full Text Available In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate (PET TeMs oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid (PAA chains inside the membrane nanochannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

  5. Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.

    Science.gov (United States)

    Zhao, Cen; Arroyo-Mora, Luis E; DeCaprio, Anthony P; Sharma, Virender K; Dionysiou, Dionysios D; O'Shea, Kevin E

    2014-12-15

    Iopamidol, widely employed as iodinated X-ray contrast media (ICM), is readily degraded in a Fe(III)-oxalate photochemical system under UV (350 nm) and visible light (450 nm) irradiation. The degradation is nicely modeled by pseudo first order kinetics. The rates of hydroxyl radical (OH) production for Fe(III)-oxalate/H2O2/UV (350 nm) and Fe(III)-oxalate/H2O2/visible (450 nm) systems were 1.19 ± 0.12 and 0.30 ± 0.01 μM/min, respectively. The steady-state concentration of hydroxyl radical (OH) for the Fe(III)-oxalate/H2O2/UV (350 nm) conditions was 10.88 ± 1.13 × 10(-14) M and 2.7 ± 0.1 × 10(-14) M for the Fe(III)-oxalate/H2O2/visible (450 nm). The rate of superoxide anion radical (O2(-)) production under Fe(III)-oxalate/H2O2/UV (350 nm) was 0.19 ± 0.02 μM/min with a steady-state concentration of 5.43 ± 0.473 × 10(-10) M. Detailed product studies using liquid chromatography coupled to Q-TOF/MS demonstrate both reduction (multiple dehalogenations) and oxidation (aromatic ring and side chains) contribute to the degradation pathways. The reduction processes appear to be initiated by the carbon dioxide anion radical (CO2(-)) while oxidation processes are consistent with OH initiated reaction pathways. Unlike most advanced oxidation processes the Fe(III)-oxalate/H2O2/photochemical system can initiate to both reductive and oxidative degradation processes. The observed reductive dehalogenation is an attractive remediation strategy for halogenated organic compounds as the process can dramatically reduce the formation of the problematic disinfection by-products often associated with oxidative treatment processes.

  6. Biologic Stress, Oxidative Stress, and Resistance to Drugs: What Is Hidden Behind

    Directory of Open Access Journals (Sweden)

    Maria Pantelidou

    2017-02-01

    Full Text Available Stress can be defined as the homeostatic, nonspecific defensive response of the organism to challenges. It is expressed by morphological, biochemical, and functional changes. In this review, we present biological and oxidative stress, as well as their interrelation. In addition to the mediation in biologic stress (central nervous, immune, and hormonal systems and oxidative stress, the effect of these phenomena on xenobiotic metabolism and drug response is also examined. It is concluded that stress decreases drug response, a result which seems to be mainly attributed to the induction of hepatic drug metabolizing enzymes. A number of mechanisms are presented. Structure-activity studies are also discussed. Vitamin E, as well as two synthetic novel compounds, seem to reduce both oxidative and biological stress and, consequently, influence drug response and metabolism.

  7. Determination of carbofuran in surface water and biological tissue by sol-gel immunoaffinity extraction and on-line preconcentration/HPLC/UV analysis.

    Science.gov (United States)

    Vera-Avila, Luz E; Márquez-Lira, Bani P; Villanueva, Marcos; Covarrubias, Rosario; Zelada, Gustavo; Thibert, Valérie

    2012-01-15

    A selective and simple analytical method for the trace level determination of carbofuran in complex environmental and biological samples was developed based on immunoaffinity extraction (IAE) followed by on-line preconcentration and HPLC/UV analysis of the purified extract. The immunosorbent for IAE was prepared by sol-gel encapsulation of monoclonal anti-carbofuran antibodies, and was fully characterized for capacity, repeatability, binding strength, binding kinetics and cross-reactivity. Method performance was evaluated with two different types of difficult samples: dam water and methanolic extracts of epithelial cervical-uterine tissue. Linear behavior and quantitative recoveries were obtained from the analysis of samples spiked with carbofuran at 0.2-4 ng/mL (dam water, 50 mL samples) and 10-40 ng/mL (biological tissue extract, 2 mL samples). RSD (n=7) and detection limits were, respectively, 10.1% (spike 0.40 ng/mL) and 0.13 ng/mL for dam water; 8.5% (spike 20 ng/mL) and 5 ng/mL for the biological tissue extract. The excellent sample purification achieved with the IAE column allows precise and accurate determination of carbofuran in complex matrices, even when using non-selective UV detection in the chromatographic analysis.

  8. Photo-oxidative degradation of levafix navy in UV/H2O2 system%UV/H2O2光助氧化降解丽华实军蓝制衣染料

    Institute of Scientific and Technical Information of China (English)

    黄晓霞; 刘茹; 蔡邦宏

    2012-01-01

    The reaction determining parameters and the reaction kinetics of the photo-oxidative degradation of a dye Levafix Navy in the UV/H2O2 system haven been studied.The UV/H2O2 system is highly efficient in degradating Levafix Navy,i.e.,a small amount of H2O2 can degrade highly concentrated dye solution.Moreover,the UV photo-decomposition of the dye molecules is found to be concurrent with the photo-oxidative degradation,both of which are apparent first-order reactions.The former reaction has an activation energy of 9.71 kJ · mol-1 with a pre-exponential factor of 1.61 min-1,and the latter has an activation energy of 50.3 kJ ·mo1-1 with a pre-exponential factor of 3.88× 105 min-1,respectively.The dye degradation efficiency peaks when the initial pH of the dye solution is strongly basic( pH=12).%本文对UV/H2 O2光助氧化降解丽华实军蓝制衣染料的效果及其影响因素和动力学进行了研究.结果表明,UV/H2O2对丽华实军蓝染料废液具有很好的处理效果,用量少,处理浓度高,且在发生光助氧化降解的同时还伴随着光分解反应.UV/H2O2体系的光助氧化反应和UV体系的光分解反应均为表观一级反应,前者活化能9.71 kJ·mol-1,指前因子1.61 min-1,后者活化能50.3 kJ·mol-1,指前因子3.88×105 min-1.染料溶液初始pH为强碱性(pH=12)时染料降解率最大.

  9. Degradation of antipyrine by UV, UV/H₂O₂ and UV/PS.

    Science.gov (United States)

    Tan, Chaoqun; Gao, Naiyun; Deng, Yang; Zhang, Yongji; Sui, Minghao; Deng, Jing; Zhou, Shiqing

    2013-09-15

    Degradation of antipyrine (AP) in water by three UV-based photolysis processes (i.e., direct UV, UV/H₂O₂, UV/persulfate (UV/PS)) was studied. For all the oxidation processes, the AP decomposition exhibited a pseudo-first-order kinetics pattern. Generally, UV/H₂O₂ and UV/PS significantly improved the degradation rate relevant to UV treatment alone. The pseudo-first-order degradation rate constants (kobs) were, to different degrees, affected by initial AP concentration, oxidant dose, pH, UV irradiation intensity, and co-existing chemicals such as humic acid, chloride, bicarbonate, carbonate and nitrate. The three oxidation processes followed the order in terms of treatment costs: UV/PS>UV>UV/H₂O₂ if the energy and chemical costs are considered. Finally, the AP degradation pathways in the UV/H₂O₂ and UV/PS processes are proposed. Results demonstrated that UV/H₂O₂ and UV/PS are potential alternatives to control water pollution caused by emerging contaminants such as AP.

  10. Improved biological performance of magnesium by micro-arc oxidation

    Directory of Open Access Journals (Sweden)

    W.H. Ma

    2015-03-01

    Full Text Available Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO, which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications.

  11. UV-Fenton氧化高浓度木糖生产废水的研究%High Concentration Xylose Wastewater Treatment by UV-Fenton Oxidization

    Institute of Scientific and Technical Information of China (English)

    田园; 陈广春; 杨峰; 唐玉斌

    2007-01-01

    采用UV-Fenton技术光催化氧化高浓度木糖生产废水,确定最佳操作条件为:pH=2.5,H2O2=46.62 g/L,H2O2/Fe2+摩尔配比为50∶1,光照反应60min.此条件下废水COD去除率最高可达91.2%.经正交试验确定影响处理效果各因素的重要性顺序为:pH>H2O2浓度>光照反应时间>H2O2/Fe2+摩尔配比.UV的加入与单独的Fenton体系存在正相关的协同作用.经UV-Fenton处理后的木糖废水,可生化性大大改善,B/C指标从0.21升高到0.49.

  12. Cerium oxide nanoparticles: green synthesis and biological applications

    Science.gov (United States)

    Charbgoo, Fahimeh; Ahmad, Mansor Bin; Darroudi, Majid

    2017-01-01

    CeO2 nanoparticles (NPs) have shown promising approaches as therapeutic agents in biology and medical sciences. The physicochemical properties of CeO2-NPs, such as size, agglomeration status in liquid, and surface charge, play important roles in the ultimate interactions of the NP with target cells. Recently, CeO2-NPs have been synthesized through several bio-directed methods applying natural and organic matrices as stabilizing agents in order to prepare biocompatible CeO2-NPs, thereby solving the challenges regarding safety, and providing the appropriate situation for their effective use in biomedicine. This review discusses the different green strategies for CeO2-NPs synthesis, their advantages and challenges that are to be overcome. In addition, this review focuses on recent progress in the potential application of CeO2-NPs in biological and medical fields. Exploiting biocompatible CeO2-NPs may improve outcomes profoundly with the promise of effective neurodegenerative therapy and multiple applications in nanobiotechnology. PMID:28260887

  13. Size distributions and temporal variations of biological aerosol particles in the Amazon rainforest characterized by microscopy and real-time UV-APS fluorescence techniques during AMAZE-08

    OpenAIRE

    J. A. Huffman; Sinha, B.; R. M. Garland; A. Snee-Pollmann; Gunthe, S. S.; Artaxo, P.; S. T. Martin; Andreae, M. O.; U. Pöschl

    2012-01-01

    As a part of the AMAZE-08 campaign during the wet season in the rainforest of central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m−3&...

  14. Effects of zinc oxide and titanium dioxide nanoparticles on green algae under visible, UVA, and UVB irradiations: no evidence of enhanced algal toxicity under UV pre-irradiation.

    Science.gov (United States)

    Lee, Woo-Mi; An, Youn-Joo

    2013-04-01

    Some metal oxide nanoparticles are photoreactive, thus raising concerns regarding phototoxicity. This study evaluated ecotoxic effects of zinc oxide nanoparticles and titanium dioxide nanoparticles to the green algae Pseudokirchneriella subcapitata under visible, UVA, and UVB irradiation conditions. The nanoparticles were prepared in algal test medium, and the test units were pre-irradiated by UV light in a photoreactor. Algal assays were also conducted with visible, UVA or UVB lights only without nanoparticles. Algal growth was found to be inhibited as the nanoparticle concentration increased, and ZnO NPs caused destabilization of the cell membranes. We also noted that the inhibitory effects on the growth of algae were not enhanced under UV pre-irradiation conditions. This phenomenon was attributed to the photocatalytic activities of ZnO NPs and TiO2 NPs in both the visible and UV regions. The toxicity of ZnO NPs was almost entirely the consequence of the dissolved free zinc ions. This study provides us with an improved understanding of toxicity of photoreactive nanoparticles as related to the effects of visible and UV lights.

  15. Effect of UV lamp irradiation during oxidation of Zr/Pt/Si structure on electrical properties of Pt/ZrO{sub 2}/Pt/Si structure

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Joon Woo [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Lim, Jae-Won, E-mail: flashlim@kigam.re.kr [Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Mimura, Kouji; Uchikoshi, Masahito [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Miyazaki, Takamichi [School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Isshiki, Minoru [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)

    2010-03-15

    Metal-insulator-metal (MIM) capacitors were fabricated using ZrO{sub 2} films and the effects of structural and native defects of the ZrO{sub 2} films on the electrical and dielectric properties were investigated. For preparing ZrO{sub 2} films, Zr films were deposited on Pt/Si substrates by ion beam deposition (IBD) system with/without substrate bias voltages and oxidized at 200 deg. C for 60 min under 0.1 MPa O{sub 2} atmosphere with/without UV light irradiation ({lambda} = 193 nm, Deep UV lamp). The ZrO{sub 2}({approx}12 nm) films on Pt({approx}100 nm)/Si were characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM), capacitance-voltage (C-V) and current-voltage (I-V) measurements were carried out on MIM structures. ZrO{sub 2} films, fabricated by oxidizing the Zr film deposited with substrate bias voltage under UV light irradiation, show the highest capacitance (784 pF) and the lowest leakage current density. The active oxygen species formed by UV irradiation are considered to play an important role in the reduction of the leakage current density, because they can reduce the density of oxygen vacancies.

  16. Treatment of textile effluent by chemical (Fenton's Reagent) and biological (sequencing batch reactor) oxidation.

    Science.gov (United States)

    Rodrigues, Carmen S D; Madeira, Luis M; Boaventura, Rui A R

    2009-12-30

    The removal of organic compounds and colour from a synthetic effluent simulating a cotton dyeing wastewater was evaluated by using a combined process of Fenton's Reagent oxidation and biological degradation in a sequencing batch reactor (SBR). The experimental design methodology was first applied to the chemical oxidation process in order to determine the values of temperature, ferrous ion concentration and hydrogen peroxide concentration that maximize dissolved organic carbon (DOC) and colour removals and increase the effluent's biodegradability. Additional studies on the biological oxidation (SBR) of the raw and previously submitted to Fenton's oxidation effluent had been performed during 15 cycles (i.e., up to steady-state conditions), each one with the duration of 11.5h; Fenton's oxidation was performed either in conditions that maximize the colour removal or the increase in the biodegradability. The obtained results allowed concluding that the combination of the two treatment processes provides much better removals of DOC, BOD(5) and colour than the biological or chemical treatment alone. Moreover, the removal of organic matter in the integrated process is particularly effective when Fenton's pre-oxidation is carried out under conditions that promote the maximum increase in wastewater biodegradability.

  17. Protective Effect of Selected Medicinal Plants against Hydrogen Peroxide Induced Oxidative Damage on Biological Substrates

    Directory of Open Access Journals (Sweden)

    Namratha Pai Kotebagilu

    2014-01-01

    Full Text Available Oxidative stress is developed due to susceptibility of biological substrates to oxidation by generation of free radicals. In degenerative diseases, oxidative stress level can be reduced by antioxidants which neutralize free radicals. Primary objective of this work was to screen four medicinal plants, namely, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, for their antioxidant property using two biological substrates—RBC and microsomes. The antioxidative ability of three solvent extracts, methanol (100% and 80% and aqueous leaf extracts, was studied at different concentrations by thiobarbituric acid reactive substances method using Fenton’s reagent to induce oxidation in the substrates. The polyphenol and flavonoid content were analyzed to relate with the observed antioxidant effect of the extracts. The phytochemical screening indicated the presence of flavonoids, polyphenols, tannins, and β-carotene in the samples. In microsomes, 80% methanol extract of Canthium and Costus and, in RBC, 80% methanol extract of Costus showed highest inhibition of oxidation and correlated well with the polyphenol and flavonoid content. From the results it can be concluded that antioxidants from medicinal plants are capable of inhibiting oxidation in biological systems, suggesting scope for their use as nutraceuticals.

  18. Inactivation of E. coli, B. subtilis spores, and MS2, T4, and T7 phage using UV/H2O2 advanced oxidation.

    Science.gov (United States)

    Mamane, Hadas; Shemer, Hilla; Linden, Karl G

    2007-07-31

    The goal of this study was to evaluate the potential of an advanced oxidation process (AOP) for microbiocidal and virucidal inactivation. The viruses chosen for this study were bacteriophage MS2, T4, and T7. In addition, Bacillus subtilis spores and Escherichia coli were studied. By using H(2)O(2) in the presence of filtered ultraviolet (UV) irradiation (UV/H(2)O(2)) to generate wavelengths above 295nm, the direct UV photolysis disinfection mechanism was minimized, while disinfection by H(2)O(2) was also negligible. Virus T4 and E. coli in phosphate buffered saline (PBS) were sensitive to >295nm filtered UV irradiation (without H(2)O(2)), while MS2 was very resistant. Addition of H(2)O(2) at 25mg/l in the presence of filtered UV irradiation over a 15min reaction time did not result in any additional disinfection of virus T4, while an additional one log inactivation for T7 and 2.5 logs for MS2 were obtained. With E. coli, only a slight additional effect was observed when H(2)O(2) was added. B. subtilis spores did not show any inactivation at any of the conditions used in this study. The OH radical exposure (CT value) was calculated to present the relationship between the hydroxyl radical dose and microbial inactivation.

  19. Inactivation of E. coli, B. subtilis spores, and MS2, T4, and T7 phage using UV/H{sub 2}O{sub 2} advanced oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Mamane, Hadas [School of Mechanical Engineering and Porter School of Environmental Studies, Tel-Aviv University, Tel-Aviv 69978 (Israel)]. E-mail: hadasmg@post.tau.ac.il; Shemer, Hilla [Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287 (United States); Linden, Karl G. [Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287 (United States)

    2007-07-31

    The goal of this study was to evaluate the potential of an advanced oxidation process (AOP) for microbiocidal and virucidal inactivation. The viruses chosen for this study were bacteriophage MS2, T4, and T7. In addition, Bacillus subtilis spores and Escherichia coli were studied. By using H{sub 2}O{sub 2} in the presence of filtered ultraviolet (UV) irradiation (UV/H{sub 2}O{sub 2}) to generate wavelengths above 295 nm, the direct UV photolysis disinfection mechanism was minimized, while disinfection by H{sub 2}O{sub 2} was also negligible. Virus T4 and E. coli in phosphate buffered saline (PBS) were sensitive to >295 nm filtered UV irradiation (without H{sub 2}O{sub 2}), while MS2 was very resistant. Addition of H{sub 2}O{sub 2} at 25 mg/l in the presence of filtered UV irradiation over a 15 min reaction time did not result in any additional disinfection of virus T4, while an additional one log inactivation for T7 and 2.5 logs for MS2 were obtained. With E. coli, only a slight additional effect was observed when H{sub 2}O{sub 2} was added. B. subtilis spores did not show any inactivation at any of the conditions used in this study. The OH radical exposure (CT value) was calculated to present the relationship between the hydroxyl radical dose and microbial inactivation.

  20. Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H{sub 2}O{sub 2}, UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2} — Comparison of transformation products, ready biodegradability and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbeck, Carlos Alexandre, E-mail: lutterbeck@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Graduate Program in Environmental Technology, Universidade de Santa Cruz do Sul — UNISC, Av. Independência, 2293, CEP 96815-900 Santa Cruz do Sul, Rio Grande do Sul (Brazil); Wilde, Marcelo Luís, E-mail: wilde@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Baginska, Ewelina, E-mail: ewelina.baginska@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Leder, Christoph, E-mail: cleder@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Machado, Ênio Leandro, E-mail: enio@unisc.br [Graduate Program in Environmental Technology, Universidade de Santa Cruz do Sul — UNISC, Av. Independência, 2293, CEP 96815-900 Santa Cruz do Sul, Rio Grande do Sul (Brazil); and others

    2015-09-15

    The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H{sub 2}O{sub 2}, UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2}. Prescreening experiments varying the H{sub 2}O{sub 2} and TiO{sub 2} concentrations were performed in order to set the best catalyst concentrations in the UV/H{sub 2}O{sub 2} and UV/TiO{sub 2} experiments, whereas the UV/Fe{sup 2+}/H{sub 2}O{sub 2} process was optimized varying the pH, Fe{sup 2+} and H{sub 2}O{sub 2} concentrations by means of the Box–Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2} processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H{sub 2}O{sub 2} treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H{sub 2}O{sub 2} treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable. - Highlights: • Full primary elimination of 5-FU was

  1. Chemical industrial wastewater treated by combined biological and chemical oxidation process.

    Science.gov (United States)

    Guomin, Cao; Guoping, Yang; Mei, Sheng; Yongjian, Wang

    2009-01-01

    Wastewaters from phenol and rubber synthesis were treated by the activated sludge process in a large-scale chemical factory in Shanghai, but the final effluent quality cannot conform with the local discharge limit without using river water for dilution. Therefore, this chemical factory had to upgrade its wastewater treatment plant. To fully use the present buildings and equipment during upgrading of the chemical factory's wastewater treatment plant and to save operation costs, a sequential biological pre-treatement, chemical oxidation, and biological post-treatment (or BCB for short) process had been proposed and investigated in a pilot trial. The pilot trial results showed that about 80% COD in the chemical wastewater could be removed through anoxic and aerobic degradation in the biological pre-treatement section, and the residual COD in the effluent of the biological pre-treatment section belongs to refractory chemicals which cannot be removed by the normal biological process. The refractory chemicals were partial oxidized using Fenton's reagent in the chemical oxidation section to improve their biodegradability; subsequently the wastewater was treated by the SBR process in the biological post-treatment section. The final effluent COD reached the first grade discharge limit (process, the operation cost of the BCB process increased by about 0.5 yuan (RMB) per cubic metre wastewater, but about 1,240,000 m(3) a(-1) dilution water could be saved and the COD emission could be cut down by 112 tonne each year.

  2. Micro-organism re-growth in wastewater disinfected by UV radiation and ozone: a micro-biological study.

    Science.gov (United States)

    Alonso, E; Santos, A; Riesco, P

    2004-04-01

    A series of disinfection experiments using UV radiation and ozone was performed on the secondary effluent from a wastewater treatment plant at a pilot plant scale. The microbial population in the inflowing wastewater and the treated outflow water were quantified for each of the treatment modules (fecal coliforms, fecal streptococci, Salmonella spp. (presence/absence), Clostridium Sulphite-reducers, Pseudomonas aeruginosa, Staphylococcus aureus, coliphages, nematodes, intestinal nematodes and pathogenic fungi). Treated water was stored in opaque tanks at a temperature between 20 and 22 degrees C, after which, a one-month study of the regrowth of the bacterial flora, nematodes and fungi was carried out. Clostridium Sulphite-reducers, pathogenic fungi and nematodes were the micro-organisms showing a greatest degree of resistence to UV- and Ozone-treatment. It was only concerning Clostridium and Pseudomonas abatement that significant elimination results were achieved with both technologies.

  3. In-situ UV-Raman study on soot combustion over TiO2 or ZrO2-supported vanadium oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    WACHS; Israel; E.

    2008-01-01

    UV-Raman spectroscopy was used to study the molecular structures of TiO2 or ZrO2-supported vana-dium oxide catalysts.The real time reaction status of soot combustion over these catalysts was de-tected by in-situ UV-Raman spectroscopy.The results indicate that TiO2 undergoes a crystalline phase transformation from anatase to rutile phase with the increasing of reaction temperature.However,no obvious phase transformation process is observed for ZrO2 support.The structures of supported va-nadium oxides also depend on the V loading.The vanadium oxide species supported on TiO2 or ZrO2 attain monolayer saturation when V loading is equal to 4(4 is the number of V atoms per 100 support metal ions).Interestingly,this loading ratio(V4/TiO2 and V4/ZrO2) gave the best catalytic activities for soot combustion reaction on both supports(TiO2 and ZrO2).The formation of surface oxygen com-plexes(SOC) is verified by in-situ UV Raman spectroscopy and the SOC mainly exist as carboxyl groups during soot combustion.The presence of NO in the reaction gas stream can promote the pro-duction of SOC.

  4. In-situ UV-Raman study on soot combustion over TiO2 or ZrO2-supported vanadium oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    LIU Jian; ZHAO Zhen; XU ChunMing; DUAN AiJun; JIANG GuiYuan; GAO JinSen; LIN WenYong; WACHS Israel E.

    2008-01-01

    UV-Raman spectroscopy was used to study the molecular structures of TiO2 or ZrO2-supported vana- dium oxide catalysts. The real time reaction status of soot combustion over these catalysts was de-tected by in-situ UV-Raman spectroscopy. The results indicate that TiO= undergoes a crystalline phase transformation from anatase to futile phase with the increasing of reaction temperature. However, no obvious phase transformation process is observed for ZrO2 support. The structures of supported va-nadium oxides also depend on the V loading. The vanadium oxide species supported on TiO2 or ZrO2 attain monolayer saturation when V loading is equal to 4 (4 is the number of V atoms per 100 support metal ions). Interestingly, this loading ratio (V4/TiO2 and V4/ZrO2) gave the best catalytic activities for soot combustion reaction on both supports (TiO2 and ZrO2). The formation of surface oxygen com-plexes (SOC) is verified by in-situ UV Raman spectroscopy and the SOC mainly exist as carboxyl groups during soot combustion. The presence of NO in the reaction gas stream can promote the pro-duction of SOC.

  5. Effect of oxidation and extent of oxidation on biologically active PACs in asphalt products.

    Science.gov (United States)

    Trumbore, David; Osborn, Linda; Blackburn, Gary; Niebo, Ron; Kriech, Anthony; Maxim, L Daniel

    2011-10-01

    Recent studies have reported divergent results in rodent cancer assays using fume condensates from a variety of asphalt products. This paper presents results of a study investigating the role of oxidation, or extent of oxidation, on these findings. Five straight run asphalts, made from widely used crude oils, were used as inputs to both production scale and laboratory oxidation units and processed to a range of softening points used in common roofing products. For each of the five asphalts studied, the oxidation reaction significantly decreased measures of polycyclic aromatic compounds (PACs) that have been linked, previously and in analyses included in this study, to tumor induction in rodent bioassays. Mutagenicity index determined by the modified Ames assay was reduced between 41% and 50% from the input asphalt to the final oxidized product. A fluorescence method tuned to a subset of PAC compounds that have been associated with carcinogenic behavior in mouse bioassays was reduced between 39% and 71%. The decrease was largest in the first quarter of the oxidation reaction. These findings indicate that oxidation, by itself, was not a likely factor in the tumor induction seen in the previous studies. Rather, other factors such as the conditions of fume generation and crude source (coupled with possible differences in distillation endpoints) were more likely to have determined the outcomes. Analyses of previously published data, presented in this paper, suggest that the modified Ames and fluorescence assays are valuable screening tools for use in future health-related asphalt research.

  6. High-valent iron in chemical and biological oxidations.

    Science.gov (United States)

    Groves, John T

    2006-04-01

    Various aspects of the reactivity of iron(IV) in chemical and biological systems are reviewed. Accumulated evidence shows that the ferryl species [Fe(IV)O](2+) can be formed under a variety of conditions including those related to the ferrous ion-hydrogen peroxide system known as Fenton's reagent. Early evidence that such a species could hydroxylate typical aliphatic C-H bonds included regioselectivities and stereospecificities for cyclohexanol hydroxylation that could not be accounted for by a freely diffusing hydroxyl radical. Iron(IV) porphyrin complexes are also found in the catalytic cycles of cytochrome P450 and chloroperoxidase. Model oxo-iron(IV) porphyrin complexes have shown reactivity similar to the proposed enzymatic intermediates. Mechanistic studies using mechanistically diagnostic substrates have implicated a radical rebound scenario for aliphatic hydroxylation by cytochrome P450. Likewise, several non-heme diiron hydroxylases, AlkB (Omega-hydroxylase), sMMO (soluble methane monooxygenase), XylM (xylene monooxygenase) and T4moH (toluene monooxygenase) all show clear indications of radical rearranged products indicating that the oxygen rebound pathway is a ubiquitous mechanism for hydrocarbon oxygenation by both heme and non-heme iron enzymes.

  7. Homogeneous, heterogeneous and biological oxidation of iron(II) in rapid sand filtration

    NARCIS (Netherlands)

    Beek, van C.G.E.M.; Hiemstra, T.; Hofs, B.; Nederlof, M.M.; Paassen, van J.A.M.; Reijnen, G.K.

    2012-01-01

    Homogeneous, heterogeneous and biological oxidation may precipitate iron(II) as iron(III) hydroxides. In this paper we evaluate the conditions under which each of these processes is dominant in rapid sand filtration (RSF). It is demonstrated that in the presence of iron(III) hydroxide precipitates h

  8. Synthesis and biological evaluation of nitric oxide-releasing matrine derivatives as anticancer agents

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A series of furoxan-based nitric oxide-releasing matrine derivatives(10a-f) were synthesized.The biological evaluation showed that compounds 10a,10b,10e and 10f had stronger cytotoxic activities than 5-fluorouracil against human hepatoma cells(HepG2) in vitro.

  9. Lipid peroxidation generates biologically active phospholipids including oxidatively N-modified phospholipids.

    Science.gov (United States)

    Davies, Sean S; Guo, Lilu

    2014-07-01

    Peroxidation of membranes and lipoproteins converts "inert" phospholipids into a plethora of oxidatively modified phospholipids (oxPL) that can act as signaling molecules. In this review, we will discuss four major classes of oxPL: mildly oxygenated phospholipids, phospholipids with oxidatively truncated acyl chains, phospholipids with cyclized acyl chains, and phospholipids that have been oxidatively N-modified on their headgroups by reactive lipid species. For each class of oxPL we will review the chemical mechanisms of their formation, the evidence for their formation in biological samples, the biological activities and signaling pathways associated with them, and the catabolic pathways for their elimination. We will end by briefly highlighting some of the critical questions that remain about the role of oxPL in physiology and disease.

  10. Sequential treatment of olive oil mill wastewater with adsorption and biological and photo-Fenton oxidation.

    Science.gov (United States)

    Aytar, Pınar; Gedikli, Serap; Sam, Mesut; Farizoğlu, Burhanettin; Çabuk, Ahmet

    2013-05-01

    Olive oil mill wastewater (OMWW), a recalcitrant pollutant, has features including high phenolic content and dark color; thereby, several chemical or physical treatments or biological processes were not able to remediate it. In this study, the treatment efficiencies of three treatments, including adsorption, biological application, and photo-Fenton oxidation were sequentially evaluated for OMWW. Adsorption, biological treatment, and photo-Fenton caused decreasing phenolic contents of 48.69 %, 59.40 %, and 95 %, respectively. However, after three sequential treatments were performed, higher reduction percentages in phenolic (total 99 %) and organic contents (90 %) were observed. Although the studied fungus has not induced significant color reduction, photo-Fenton oxidation was considered to be an attractive solution, especially for color reduction. Besides, toxicity of OMWW treatment was significantly reduced.

  11. Interactive effects of herbicide and enhanced UV-B on growth, oxidative damage and the ascorbate-glutathione cycle in two Azolla species.

    Science.gov (United States)

    Prasad, Sheo Mohan; Kumar, Sushil; Parihar, Parul; Singh, Rachana

    2016-11-01

    A field experiment was conducted to investigate the impact of alone and combined exposures of herbicide pretilachlor (5, 10 and 20μgml(-1)) and enhanced UV-B radiation (UV-B1; ambient +2.2kJm(-2) day(-1) and UV-B2; ambient +4.4kJm(-2) day(-1)) on growth, oxidative stress and the ascorbate-glutathione (AsA-GSH) cycle in two agronomically important Azolla spp. viz., Azolla microphylla and Azolla pinnata. Decreased relative growth rate (RGR) in both the species under tested stress could be linked to enhanced oxidative stress, thus higher H2O2 accumulation was observed, that in turn might have caused severe damage to lipids and proteins, thereby decreasing membrane stability. The effects were exacerbated when spp. were exposed to combined treatments of enhanced UV-B and pretilachlor. Detoxification of H2O2 is regulated by enzymes/metabolites of AsA-GSH cycle such as ascorbate peroxidase (APX) and glutathione reductase (GR) activity that were found to be stimulated. While, dehydroascorabte reductase (DHAR) activity, and the amount of metabolites: ascorbate (AsA), glutathione (GSH) and ratios of reduced/oxidized AsA (AsA/DHA) and GSH (GSH/GSSG), showed significant reduction with increasing doses of both the stressors, either applied alone or in combination. Glutathione-S-transferase (GST), an enzyme involved in scavenging of xenobiotics, was found to be stimulated under the tested stress. This study suggests that decline in DHAR activity and in AsA/DHA ratio might have led to enhanced H2O2 accumulation, thus decreased RGR was noticed under tested stress in both the species and the effect was more pronounced in A. pinnata. Owing to better performance of AsA-GSH cycle in A. microphylla, this study substantiates the view that A. microphylla is more tolerant than A. pinnata.

  12. The oxidation of As(III) in groundwater using biological manganese removal filtration columns.

    Science.gov (United States)

    Yang, Hong; Sun, Wenyong; Ge, Huoqing; Yao, Renda

    2015-01-01

    Arsenic is known as a toxic element to humans, and has been reported to co-exist with iron and manganese in groundwater worldwide. The typical method for arsenic removal from groundwater is to oxidize trivalent (As(III)) to pentavalent (As(V)) followed by the As(V) removal. This study aims to evaluate the oxidization efficiency of As(III) in a mature biological manganese (Mn(2+)) removal filtration system with different elevated influent As(III) concentrations. The effects of influent Mn(2+) concentrations, influent As(III) concentrations, filtration rates and dissolved oxygen (DO) levels on the efficiency of As(III) oxidation were assessed. The results showed that As(III) oxidation can be simultaneously achieved with removing Mn(2+) in the filtration system. The oxidation efficiency was not impacted by increasing the influent As(III) concentration up to nearly 2500 µg L(-1), but the filtration rate was limited at 11 m h(-1) for maintaining the effluent As(III) concentration below 10 µg L(-1). The oxidation process followed first-order kinetics with the constant reaching 0.56-0.61 min(-1). The As(III) oxidation process was most likely to be mediated by the bacterial community initially developed for Mn(2+) removal in the filtration system, which performed the catalytic oxidation for As(III).

  13. Experimental Study on Treatment of Pharmaceutical Wastewater with UV-Fenton Oxidation%UV-Fenton法预处理某制药厂废水的实验研究

    Institute of Scientific and Technical Information of China (English)

    陈琳; 张争民

    2015-01-01

    The pharmaceutical wastewater, a class of industrial wastewater, is characterized by high concentra⁃tion and low bio-degradability. The treatment efficiency had been compared between Fenton and UV-Fenton of dosage, initial pH, reaction time, and so on. The results showed that the treatment efficiency of UV-Fen⁃ton oxidation process was better than Fenton. The optimal reaction conditions of Fenton were as follows: the dosage of FeSO4·7H2O and H2O2 were 0.036 mol/L and 0.128 mol/L respectively, the initial pH was 4.3, the reaction time was 2h, and the removal efficiency of CODCr was 43.9%. However, the optimal conditions of UV-Fenton were as follows: the dosage of FeSO4·7H2O and H2O2 were 0.029 mol/L and 0.102 mol/L respec⁃tively, the initial pH was 4.3, the reaction time of UV and Fenton were 7 min and 75 min respectively and the removal efficiency of CODCr was 63.5%. What’s more, the B/C was increased to 0.39, which showed that UV-Fenton oxidation could improve biodegradability of the pharmaceutical wastewater.%制药废水是一种难生物降解的高浓度有机工业废水,处理困难.研究以某制药股份有限公司综合排放废水为对象,分别采用Fenton和UV-Fenton法对制药废水进行处理,分析试剂投加量、反应初始pH和反应时间等对反应的影响.结果表明,Fenton法处理制药废水的最佳条件为:FeSO4·7H2O投加0.036 mol/L,H2O2投加0.128 mol/L,初始pH为4.3,反应时间为2 h,CODCr去除率为43.9%. UV-Fenton法处理制药废水缩短反应时间,减少试剂投加量,最佳处理条件为:UV处理时间为7 min,FeSO4·7H2O投加0.029 mol/L,H2O2投加0.102 mol/L,初始pH为4.3,反应时间为75 min,最佳条件下CODCr去除率优于Fenton法,可达63.5%,且污水B/C增至0.39,提高可生化性.

  14. Application of Advanced Oxidation Technological Process of UV/H2O2 in Drinking Water Treatment%紫外/过氧化氢(UV/H2O2)高级氧化工艺在饮用水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    夏萍; 张东; 周新宇; 王铮

    2012-01-01

    To study the efficiency of UV, UV+GAC, UV/H2O2, UV/H2O2 + GAC water treatment on removing atrazine, 2-Methylisobomeol (2-MIB), geosmine and disinfection by-products production, a UV/H2O2 pilot test equipment is connected to the outlet of sand filter and target pollutants were injected into the filtered water. The results show that UV/H2O2 + GAC advanced oxidation technology has the best effect on removing geosmine, the removal rate of which reaches over 95 %. The removal effects of 2-MIB and atrazine is approximate, the removal rates of which are about 70 % by UV/H2O2+GAC treatment. Less disinfection by-products is formed in UV/H2O2 water treatment.%通过砂滤池出水后接UV/H2O2高级氧化中试试验设备并投加特征污染物,考察了UV,UV+颗粒活性炭(GAC),UV/H2O2,UV/H2O2+GAC工艺对阿特拉津、嗅味物质及消毒副产物生成量的去除效果,发现UV/H2O2+GAC工艺对土臭素去除效果最好,去除率高达95%以上;对MIB和阿特拉津的去除效果比较接近,去除率在70%以上;UV/H2O2能有效去除消毒副产物前体物、减少消毒副产物的生成.

  15. Sequential ozone advanced oxidation and biological oxidation processes to remove selected pharmaceutical contaminants from an urban wastewater.

    Science.gov (United States)

    Espejo, Azahara; Aguinaco, Almudena; García-Araya, J F; Beltrán, Fernando J

    2014-01-01

    Sequential treatments consisting in a chemical process followed by a conventional biological treatment, have been applied to remove mixtures of nine contaminants of pharmaceutical type spiked in a primary sedimentation effluent of a municipal wastewater. Combinations of ozone, UVA black light (BL) and Fe(III) or Fe₃O₄ catalysts constituted the chemical systems. Regardless of the Advanced Oxidation Process (AOP), the removal of pharmaceutical compounds was achieved in 1 h of reaction, while total organic carbon (TOC) only diminished between 3.4 and 6%. Among selected ozonation systems to be implemented before the biological treatment, the application of ozone alone in the pre-treatment stage is recommended due to the increase of the biodegradability observed. The application of ozone followed by the conventional biological treatment leads high TOC and COD removal rates, 60 and 61%, respectively, and allows the subsequent biological treatment works with shorter hydraulic residence time (HRT). Moreover, the influence of the application of AOPs before and after a conventional biological process was compared, concluding that the decision to take depends on the characterization of the initial wastewater with pharmaceutical compounds.

  16. Photocatalytic Degradation of Toluene, Butyl Acetate and Limonene under UV and Visible Light with Titanium Dioxide-Graphene Oxide as Photocatalyst

    Directory of Open Access Journals (Sweden)

    Birte Mull

    2017-01-01

    Full Text Available Photocatalysis is a promising technique to reduce volatile organic compounds indoors. Titanium dioxide (TiO2 is a frequently-used UV active photocatalyst. Because of the lack of UV light indoors, TiO2 has to be modified to get its working range shifted into the visible light spectrum. In this study, the photocatalytic degradation of toluene, butyl acetate and limonene was investigated under UV LED light and blue LED light in emission test chambers with catalysts either made of pure TiO2 or TiO2 modified with graphene oxide (GO. TiO2 coated with different GO amounts (0.75%–14% were investigated to find an optimum ratio for the photocatalytic degradation of VOC in real indoor air concentrations. Most experiments were performed at a relative humidity of 0% in 20 L emission test chambers. Experiments at 40% relative humidity were done in a 1 m³ emission test chamber to determine potential byproducts. Degradation under UV LED light could be achieved for all three compounds with almost all tested catalyst samples up to more than 95%. Limonene had the highest degradation of the three selected volatile organic compounds under blue LED light with all investigated catalyst samples.

  17. Methane-Oxidizing Enzymes: An Upstream Problem in Biological Gas-to-Liquids Conversion.

    Science.gov (United States)

    Lawton, Thomas J; Rosenzweig, Amy C

    2016-08-03

    Biological conversion of natural gas to liquids (Bio-GTL) represents an immense economic opportunity. In nature, aerobic methanotrophic bacteria and anaerobic archaea are able to selectively oxidize methane using methane monooxygenase (MMO) and methyl coenzyme M reductase (MCR) enzymes. Although significant progress has been made toward genetically manipulating these organisms for biotechnological applications, the enzymes themselves are slow, complex, and not recombinantly tractable in traditional industrial hosts. With turnover numbers of 0.16-13 s(-1), these enzymes pose a considerable upstream problem in the biological production of fuels or chemicals from methane. Methane oxidation enzymes will need to be engineered to be faster to enable high volumetric productivities; however, efforts to do so and to engineer simpler enzymes have been minimally successful. Moreover, known methane-oxidizing enzymes have different expression levels, carbon and energy efficiencies, require auxiliary systems for biosynthesis and function, and vary considerably in terms of complexity and reductant requirements. The pros and cons of using each methane-oxidizing enzyme for Bio-GTL are considered in detail. The future for these enzymes is bright, but a renewed focus on studying them will be critical to the successful development of biological processes that utilize methane as a feedstock.

  18. Influence of methanethiol on biological sulphide oxidation in gas treatment system.

    Science.gov (United States)

    Roman, Pawel; Bijmans, Martijn F M; Janssen, Albert J H

    2016-01-01

    Inorganic and organic sulphur compounds such as hydrogen sulphide (H2S) and thiols (RSH) are unwanted components in sour gas streams (e.g. biogas and refinery gases) because of their toxicity, corrosivity and bad smell. Biological treatment processes are often used to remove H2S at small and medium scales (<50 tons per day of H2S). Preliminarily research by our group focused on achieving maximum sulphur production from biological H2S oxidation in the presence of methanethiol. In this paper the underlying principles have been further studied by assessing the effect of methanethiol on the biological conversion of H2S under a wide range of redox conditions covering not only sulphur but also sulphate-producing conditions. Furthermore, our experiments were performed in an integrated system consisting of a gas absorber and a bioreactor in order to assess the effect of methanethiol on the overall gas treatment efficiency. This study shows that methanethiol inhibits the biological oxidation of H2S to sulphate by way of direct suppression of the cytochrome c oxidase activity in biomass, whereas the oxidation of H2S to sulphur was hardly affected. We estimated the kinetic parameters of biological H2S oxidation that can be used to develop a mathematical model to quantitatively describe the biodesulphurization process. Finally, it was found that methanethiol acts as a competitive inhibitor; therefore, its negative effect can be minimized by increasing the enzyme (biomass) concentration and the substrate (sulphide) concentration, which in practice means operating the biodesulphurization systems under low redox conditions.

  19. Destruction of microcystins (cyanotoxins) by UV-254 nm-based direct photolysis and advanced oxidation processes (AOPs): influence of variable amino acids on the degradation kinetics and reaction mechanisms.

    Science.gov (United States)

    He, Xuexiang; de la Cruz, Armah A; Hiskia, Anastasia; Kaloudis, Triantafyllos; O'Shea, Kevin; Dionysiou, Dionysios D

    2015-05-01

    Hepatotoxic microcystins (MCs) are the most frequently detected group of cyanobacterial toxins. This study investigated the degradation of common MC variants in water, MC-LR, MC-RR, MC-YR and MC-LA, by UV-254 nm-based processes, UV only, UV/H2O2, UV/S2O8(2-) and UV/HSO5(-). Limited direct photolysis of MCs was observed, while the addition of an oxidant significantly improved the degradation efficiency with an order of UV/S2O8(2-) > UV/HSO5(-) > UV/H2O2 at the same initial molar concentration of the oxidant. The removal of MC-LR by UV/H2O2 appeared to be faster than another cyanotoxin, cylindrospermopsin, at either the same initial molar concentration or the same initial organic carbon concentration of the toxin. It suggested a faster reaction of MC-LR with hydroxyl radical, which was further supported by the determined second-order rate constant of MCs with hydroxyl radical. Both isomerization and photohydration byproducts were observed in UV only process for all four MCs; while in UV/H2O2, hydroxylation and diene-Adda double bond cleavage byproducts were detected. The presence of a tyrosine in the structure of MC-YR significantly promoted the formation of monohydroxylation byproduct m/z 1061; while the presence of a second arginine in MC-RR led to the elimination of a guanidine group and the absence of double bond cleavage byproducts. It was therefore demonstrated in this study that the variable amino acids in the structure of MCs influenced not only the degradation kinetics but also the preferable reaction mechanisms.

  20. On the biologic role of the reaction of NO with oxidized cytochrome c oxidase.

    Science.gov (United States)

    Antunes, Fernando; Boveris, Alberto; Cadenas, Enrique

    2007-10-01

    The inhibition of cytochrome c oxidase (CcOX) by nitric oxide (NO) is analyzed with a mathematical model that simulates the metabolism in vivo. The main results were the following: (a) We derived novel equations for the catalysis of CcOX that can be used to predict CcOX inhibition in any tissue for any [NO] or [O(2)]; (b) Competitive inhibition (resulting from the reversible binding of NO to reduced CcOX) emerges has the sole relevant component of CcOX inhibition under state 3 in vivo; (c) In state 4, contribution of uncompetitive inhibition (resulting from the reaction of oxidized CcOX with NO) represents a significant nonmajority fraction of inhibition, being favored by high [O(2)]; and (d) The main biologic role of the reaction between NO and oxidized CcOX is to consume NO. By reducing [NO], this reaction stimulates, rather than inhibits, respiration. Finally, we propose that the biologic role of NO as an inhibitor of CcOX is twofold: in state 4, it avoids an excessive buildup of mitochondrial membrane potential that triggers rapid production of oxidants, and in state 3, increases the efficiency of oxidative phosphorylation by increasing the ADP/O ratio, supporting the therapeutic use of NO in situations in which mitochondria are dysfunctional.

  1. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions and novel technologies

    Directory of Open Access Journals (Sweden)

    Frank eSchreiber

    2012-10-01

    Full Text Available Nitrous oxide (N2O is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH or the reduction of nitrite (NO2- to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO2- to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria. In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO2-, NH2OH and nitroxyl (HNO. Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser based absorption spectroscopy. In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build-up.

  2. Treatment of linear alkylbenzene sulfonate (LAS) wastewater by internal electrolysis--biological contact oxidation process.

    Science.gov (United States)

    Cao, X Z; Li, Y M

    2011-01-01

    Surfactant wastewater is usually difficult to treat due to its toxicity and poor biodegradability. A separate physico-chemical or biochemical treatment method achieves a satisfactory effect with difficulty. In this study, treatment of the wastewater collected from a daily chemical plant by the combination processes of Fe/C internal electrolysis and biological contact oxidation was investigated. For the internal electrolysis process, the optimal conditions were: pH = 4-5, Fe/C = (10-15):1, air-water ratio = (10-20):1 and hydraulic retention time (HRT)= 2 h. For the biological contact oxidation process, the optimal conditions were: HRT = 12 h, DO = 4.0-5.0 mg/L. Treated by the above combined processes, the effluent could meet the I-grade criteria specified in Integrated Wastewater Discharge Standard of China (GB 8978-1996). The results provide valuable information for full-scale linear alkylbenzene sulfonate wastewater treatment.

  3. UV Differentially Induces Oxidative Stress, DNA Damage and Apoptosis in BCR-ABL1-Positive Cells Sensitive and Resistant to Imatinib

    Directory of Open Access Journals (Sweden)

    Ewelina Synowiec

    2015-08-01

    Full Text Available Chronic myeloid leukemia (CML cells express the active BCR-ABL1 protein, which has been targeted by imatinib in CML therapy, but resistance to this drug is an emerging problem. BCR-ABL1 induces endogenous oxidative stress promoting genomic instability and imatinib resistance. In the present work, we investigated the extent of oxidative stress, DNA damage, apoptosis and expression of apoptosis-related genes in BCR-ABL1 cells sensitive and resistant to imatinib. The resistance resulted either from the Y253H mutation in the BCR-ABL1 gene or incubation in increasing concentrations of imatinib (AR. UV irradiation at a dose rate of 0.12 J/(m2·s induced more DNA damage detected by the T4 pyrimidine dimers glycosylase and hOGG1, recognizing oxidative modifications to DNA bases in imatinib-resistant than -sensitive cells. The resistant cells displayed also higher susceptibility to UV-induced apoptosis. These cells had lower native mitochondrial membrane potential than imatinib-sensitive cells, but UV-irradiation reversed that relationship. We observed a significant lowering of the expression of the succinate dehydrogenase (SDHB gene, encoding a component of the complex II of the mitochondrial respiratory chain, which is involved in apoptosis sensing. Although detailed mechanism of imatinib resistance in AR cells in unknown, we detected the presence of the Y253H mutation in a fraction of these cells. In conclusion, imatinib-resistant cells may display a different extent of genome instability than their imatinib-sensitive counterparts, which may follow their different reactions to both endogenous and exogenous DNA-damaging factors, including DNA repair and apoptosis.

  4. Modeling a full scale oxidation ditch system, coupling hydrodynamics and biological kinetics using ASM1 model

    Energy Technology Data Exchange (ETDEWEB)

    Haouech, L.; Sperandio, M.; Cock, A.; Shayeb, H.

    2009-07-01

    Optimising the aeration in oxidation ditch aims on one hand, a better wastewater quality and on the other hand, a reduction of the energy expenses of the treatment. given that the energy expenses relative to the aeration represents 60 to 80% of the operating costs of a wastewater treatment plant and given that the biological activity is strictly dependent on dissolved oxygen, the transfer of oxygen is considered as one of the key parameters of the process. (Author) 8 refs.

  5. Quinoxaline 1,4-di-N-Oxides: Biological Activities and Mechanisms of Actions

    OpenAIRE

    Cheng, Guyue; Sa, Wei; Cao, Chen; Guo, Liangliang; Hao, Haihong; Liu, Zhenli; Wang, Xu; Yuan, Zonghui

    2016-01-01

    Quinoxaline 1,4-di-N-oxides (QdNOs) have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and ba...

  6. Size distributions and temporal variations of biological aerosol particles in the Amazon rainforest characterized by microscopy and real-time UV-APS fluorescence techniques during AMAZE-08

    Directory of Open Access Journals (Sweden)

    J. A. Huffman

    2012-12-01

    Full Text Available As a part of the AMAZE-08 campaign during the wet season in the rainforest of central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS was operated for continuous measurements of fluorescent biological aerosol particles (FBAP. In the coarse particle size range (> 1 μm the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m−3 and 0.72 μg m−3 (0.42–1.19 μg m−3, respectively, accounting for 24% (11–41% of total particle number and 47% (25–65% of total particle mass. During the five-week campaign in February–March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM, light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no true fungal staining. This mode may have consisted of single bacterial cells, brochosomes, various fragments of biological material, and small Chromalveolata (Chromista spores. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF techniques using 355 nm excitation provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles in a pristine

  7. Size distributions and temporal variations of biological aerosol particles in the Amazon rainforest characterized by microscopy and real-time UV-APS fluorescence techniques during AMAZE-08

    Science.gov (United States)

    Huffman, J. A.; Sinha, B.; Garland, R. M.; Snee-Pollmann, A.; Gunthe, S. S.; Artaxo, P.; Martin, S. T.; Andreae, M. O.; Pöschl, U.

    2012-12-01

    As a part of the AMAZE-08 campaign during the wet season in the rainforest of central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m-3 (4.0-13.2 × 104 m-3) and 0.72 μg m-3 (0.42-1.19 μg m-3), respectively, accounting for 24% (11-41%) of total particle number and 47% (25-65%) of total particle mass. During the five-week campaign in February-March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM), light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP) mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no true fungal staining. This mode may have consisted of single bacterial cells, brochosomes, various fragments of biological material, and small Chromalveolata (Chromista) spores. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF) techniques using 355 nm excitation provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles in a pristine environment. We also show some limitations of using the instrument for ambient monitoring of

  8. UV-visible spectroscopic analysis of electrical properties in alkali metal-doped amorphous zinc tin oxide thin-film transistors.

    Science.gov (United States)

    Lim, Keon-Hee; Kim, Kyongjun; Kim, Seonjo; Park, Si Yun; Kim, Hyungjun; Kim, Youn Sang

    2013-06-04

    Solution-processed and alkali metals, such as Li and Na, are introduced in doped amorphous zinc tin oxide (ZTO) semiconductor TFTs, which show better electrical performance, such as improved field effect mobility, than intrinsic amorphous ZTO semiconductor TFTs. Furthermore, by using spectroscopic UV-visible analysis we propose a comprehensive technique for monitoring the improved electrical performance induced by alkali metal doping in terms of the change in optical properties. The change in the optical bandgap supported by the Burstein-Moss theory could successfully show a mobility increase that is related to interstitial doping of alkali metal in ZTO semiconductors.

  9. Simultaneous determination of ammonia, dimethylamine, trimethylamine and trimethylamine-N-oxide in fish extracts by capillary electrophoresis with indirect UV-detection

    DEFF Research Database (Denmark)

    Timm Heinrich, Maike; Jørgensen, Bo

    2002-01-01

    A capillary electrophoretic method with indirect UV detection is described for simultaneous determination of ammonia, dimethylamine (DMA), trimethylamine (TMA) and trimethylamine-N- oxide (TMAO) in aqueous extracts of fish, A buffer consisting of 4 mM formic acid, 5 mM copper(II)sulfate and 3 m......M. The detection limit for ammonia, DMA, TMA, and TMAO was less than 0.04 mM, corresponding to 2 mg nitrogen per 100 g fish. As an extra benefit, the method also provided a quantitative determination of potassium, sodium, calcium and magnesium ions. (C) 2002 Elsevier Science Ltd. All rights reserved....

  10. Emission spectra of the sol-gel glass doped with europium(III) complexes of picolinic acid N-oxide-A new UV-light sensor

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, P. [Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of Engineering and Economics, Lower Silesian University of Economics, Wroclaw (Poland); Macalik, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland); Hanuza, J. [Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of Engineering and Economics, Lower Silesian University of Economics, Wroclaw (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)], E-mail: j.hanuza@int.pan.wroc.pl

    2008-02-28

    New europium complexes of picolinic acid N-oxides have been synthesised and introduced into sol-gel matrices. Their application as UV-light sensors has been considered. The sequence of the electronic levels for Eu{sup 3+} ions has been determined from the absorption and emission studies and assigned to the respective electron transitions. The lifetimes of the excited states have been detected and analysed. The role of the CT transition inside the picolinic ligand and its influence on the ligand to metal charge transfer (LMCT) have been discussed.

  11. Pilot-scale UV/H2O2 advanced oxidation process for municipal reuse water: Assessing micropollutant degradation and estrogenic impacts on goldfish (Carassius auratus L.).

    Science.gov (United States)

    Shu, Zengquan; Singh, Arvinder; Klamerth, Nikolaus; McPhedran, Kerry; Bolton, James R; Belosevic, Miodrag; Gamal El-Din, Mohamed

    2016-09-15

    Low concentrations (ng/L-μg/L) of emerging micropollutant contaminants in municipal wastewater treatment plant effluents affect the possibility to reuse these waters. Many of those micropollutants elicit endocrine disrupting effects in aquatic organisms resulting in an alteration of the endocrine system. A potential candidate for tertiary municipal wastewater treatment of these micropollutants is ultraviolet (UV)/hydrogen peroxide (H2O2) as an advanced oxidation process (AOP) which was currently applied to treat the secondary effluent of the Gold Bar Wastewater Treatment Plant (GBWWTP) in Edmonton, AB, Canada. A new approach is presented to predict the fluence-based degradation rate constants (kf') of environmentally occurring micropollutants including carbamazepine [(0.87-1.39) × 10(-3) cm(2)/mJ] and 2,4-Dichlorophenoxyacetic acid (2,4-D) [(0.60-0.91) × 10(-3) cm(2)/mJ for 2,4-D] in a medium pressure (MP) UV/H2O2 system based on a previous bench-scale investigation. Rather than using removal rates, this approach can be used to estimate the performance of the MP UV/H2O2 process for degrading trace contaminants of concern found in municipal wastewater. In addition to the ability to track contaminant removal/degradation, evaluation of the MP UV/H2O2 process was also accomplished by identifying critical ecotoxicological endpoints (i.e., estrogenicity) of the treated wastewater. Using quantitative PCR, mRNA levels of estrogen-responsive (ER) genes ERα1, ERα2, ERβ1, ERβ2 and NPR as well as two aromatase encoding genes (CYP19a and CYP19b) in goldfish (Carassius auratus L.) were measured during exposure to the GBWWTP effluent before and after MP UV/H2O2 treatment (a fluence of 1000 mJ/cm(2) and 20 mg/L of H2O2) in spring, summer and fall. Elevated expression of estrogen-responsive genes in goldfish exposed to UV/H2O2 treated effluent (a 7-day exposure) suggested that the UV/H2O2 process may induce acute estrogenic disruption to goldfish principally because

  12. Cholesteryl Ester Hydroperoxides Are Biologically Active Components of Minimally Oxidized Low Density Lipoprotein*S⃞

    Science.gov (United States)

    Harkewicz, Richard; Hartvigsen, Karsten; Almazan, Felicidad; Dennis, Edward A.; Witztum, Joseph L.; Miller, Yury I.

    2008-01-01

    Oxidation of low density lipoprotein (LDL) occurs in vivo and significantly contributes to the development of atherosclerosis. An important mechanism of LDL oxidation in vivo is its modification with 12/15-lipoxygenase (LO). We have developed a model of minimally oxidized LDL (mmLDL) in which native LDL is modified by cells expressing 12/15LO. This mmLDL activates macrophages inducing membrane ruffling and cell spreading, activation of ERK1/2 and Akt signaling, and secretion of proinflammatory cytokines. In this study, we found that many of the biological activities of mmLDL were associated with cholesteryl ester (CE) hydroperoxides and were diminished by ebselen, a reducing agent. Liquid chromatography coupled with mass spectroscopy demonstrated the presence of many mono- and polyoxygenated CE species in mmLDL but not in native LDL. Nonpolar lipid extracts of mmLDL activated macrophages, although to a lesser degree than intact mmLDL. The macrophage responses were also induced by LDL directly modified with immobilized 12/15LO, and the nonpolar lipids extracted from 12/15LO-modified LDL contained a similar set of oxidized CE. Cholesteryl arachidonate modified with 12/15LO also activated macrophages and contained a similar collection of oxidized CE molecules. Remarkably, many of these oxidized CE were found in the extracts of atherosclerotic lesions isolated from hyperlipidemic apoE–/– mice. These results suggest that CE hydroperoxides constitute a class of biologically active components of mmLDL that may be relevant to proinflammatory activation of macrophages in atherosclerotic lesions. PMID:18263582

  13. Combined operando Raman/UV-Vis-NIR spectroscopy as a tool to study supported metal oxide catalysts at work

    NARCIS (Netherlands)

    Tinnemans, Stanislaus Josephus

    2006-01-01

    A novel set-up has been developed in which two complementary spectroscopic techniques, namely operando Raman and UV-Vis-NIR spectroscopy, are combined. With this set-up it is possible to characterize catalytic materials under reaction conditions (high temperature, normal pressure) and in this way on

  14. Preparation and Characterization of Chitosan/Zinc Oxide Nanoparticles for Imparting Antimicrobial and UV Protection to Cotton Fabric

    Directory of Open Access Journals (Sweden)

    M. M. AbdElhady

    2012-01-01

    Full Text Available Synthesis of chitosan/ZnO nanoparticles was performed using different concentrations of ZnO at different temperatures. Nanoparticles of ZnO/chitosan were prepared in rod form with average length 60 nm and average width 5–15 nm. Thus, obtained nanoparticles of ZnO/chitosan were characterized using UV spectrophotometer, FTIR, TEM, X-ray, and SEM. Size and shape of chitosan/ZnO nanoparticles relied on conditions of their synthesis. Notably, chitosan/ZnO in rod form with average length of 60 nm and average width 5–15 nm could be achieved. Application of chitosan/ZnO nanoparticles to cotton fabric conferred on the latter antibacterial and UV protection properties. Cotton fabric was characterized using SEM, ultraviolet protection factor (UPF rating, and antibacterial (gram-positive and gram-negative characteristics. Finished cotton fabric exhibited good antibacterial properties against gram-positive and gram-negative bacteria. The UV testes indicated a significant improvement in UV protection of finished cotton fabric which is increasing by increasing the concentration of nanoparticles of ZnO/chitosan.

  15. Supported Zinc Oxide Photocatalyst for Decolorization and Mineralization of Orange G Dye Wastewater under UV365 Irradiation

    Directory of Open Access Journals (Sweden)

    Ming-Chin Chang

    2013-01-01

    Full Text Available To solve the environmental challenge of textile wastewater, a UV/ZnO photocatalytic system was proposed. The objective of this study was to prepare a photocatalytic system by utilizing both cold cathode fluorescent light (CCFL UV irradiation and steel mesh supported ZnO nanoparticles in a closed reactor for the degradation of azo dye C.I. Orange G (OG. Various operating parameters such as reaction time, preparation temperature, mixing speed, ZnO dosage, UV intensity, pH, initial dye concentration, and service duration were studied. Results presented efficient color and total organic carbon (TOC removal of the OG azo dye by the designed photocatalytic system. The optimal ZnO dosage for color removal was 60 g m−2. An alkaline pH of 11.0 was sufficient for photocatalytic decolorization and mineralization. The rate of color removal decreased with the increase in the initial dye concentration. However, the rate of color removal increased with the increase in the UV intensity. The steel mesh supported ZnO can be used repeatedly over 10 times without losing the color removal efficiency for 120 min reaction time. Results of Fourier transform infrared (FTIR and ion chromatography (IC indicated the breakage of N=N bonds and formation of sulfate, nitrate, and nitrite as the major and minor products. The observation indicated degradation of dye molecules.

  16. GaN-Based High-k Praseodymium Oxide Gate MISFETs with P2S5/(NH42SX + UV Interface Treatment Technology

    Directory of Open Access Journals (Sweden)

    Chao-Wei Lin

    2012-01-01

    Full Text Available This study examines the praseodymium-oxide- (Pr2O3- passivated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs with high dielectric constant in which the AlGaN Schottky layers are treated with P2S5/(NH42SX + ultraviolet (UV illumination. An electron-beam evaporated Pr2O3 insulator is used instead of traditional plasma-assisted chemical vapor deposition (PECVD, in order to prevent plasma-induced damage to the AlGaN. In this work, the HEMTs are pretreated with P2S5/(NH42SX solution and UV illumination before the gate insulator (Pr2O3 is deposited. Since stable sulfur that is bound to the Ga species can be obtained easily and surface oxygen atoms are reduced by the P2S5/(NH42SX pretreatment, the lowest leakage current is observed in MIS-HEMT. Additionally, a low flicker noise and a low surface roughness (0.38 nm are also obtained using this novel process, which demonstrates its ability to reduce the surface states. Low gate leakage current Pr2O3 and high-k AlGaN/GaN MIS-HEMTs, with P2S5/(NH42SX + UV illumination treatment, are suited to low-noise applications, because of the electron-beam-evaporated insulator and the new chemical pretreatment.

  17. Spectroscopic characteristic (FT-IR, FT-Raman, UV, 1H and 13C NMR), theoretical calculations and biological activity of alkali metal homovanillates

    Science.gov (United States)

    Samsonowicz, M.; Kowczyk-Sadowy, M.; Piekut, J.; Regulska, E.; Lewandowski, W.

    2016-04-01

    The structural and vibrational properties of lithium, sodium, potassium, rubidium and cesium homovanillates were investigated in this paper. Supplementary molecular spectroscopic methods such as: FT-IR, FT-Raman in the solid phase, UV and NMR were applied. The geometrical parameters and energies were obtained from density functional theory (DFT) B3LYP method with 6-311++G** basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned. Geometric and magnetic aromaticity indices, atomic charges, dipole moments, HOMO and LUMO energies were also calculated. The microbial activity of investigated compounds was tested against Bacillus subtilis (BS), Pseudomonas aeruginosa (PA), Escherichia coli (EC), Staphylococcus aureus (SA) and Candida albicans (CA). The relationship between the molecular structure of tested compounds and their antimicrobial activity was studied. The principal component analysis (PCA) was applied in order to attempt to distinguish the biological activities of these compounds according to selected band wavenumbers. Obtained data show that the FT-IR spectra can be a rapid and reliable analytical tool and a good source of information for the quantitative analysis of the relationship between the molecular structure of the compound and its biological activity.

  18. Fabrication of solution-processed amorphous indium zinc oxide thin-film transistors at low temperatures using deep-UV irradiation under wet conditions

    Science.gov (United States)

    Park, Jee Ho; Chae, Soo Sang; Yoo, Young Bum; Lee, Ji Hoon; Lee, Tae Il; Baik, Hong Koo

    2014-03-01

    We fabricated solution-processed indium zinc oxide (IZO) thin film transistors (TFTs) at annealing temperatures as low as 250 °C using deep UV (DUV) irradiation in water vapor medium. The DUV light decomposed the carbon compounds in the IZO films, and the hydroxyl radicals generated when water vapor reacted with ozone effectively oxidized the films. These phenomena were confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Finally, we fabricated DUV-treated IZO TFTs in water-vapor medium at 250 °C with a mobility of 1.2 cm2/Vs and an on/off current ratio of 2.66 × 106.

  19. Investigation of material property influenced stoichiometric deviations as evidenced during UV laser-assisted atom probe tomography in fluorite oxides

    Energy Technology Data Exchange (ETDEWEB)

    Valderrama, Billy; Henderson, Hunter B. [Department of Materials Science and Engineering, University of Florida, 100 Rhines Hall, Gainesville, FL 32611 (United States); Yablinsky, Clarissa A. [Department of Nuclear Engineering, University of Wisconsin-Madison, 921 ERB, 1500 Engineering Drive, Madison, WI 53706 (United States); Gan, Jian [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States); Allen, Todd R. [Department of Nuclear Engineering, University of Wisconsin-Madison, 921 ERB, 1500 Engineering Drive, Madison, WI 53706 (United States); Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States); Manuel, Michele V., E-mail: mmanuel@mse.ufl.edu [Department of Materials Science and Engineering, University of Florida, 100 Rhines Hall, Gainesville, FL 32611 (United States)

    2015-09-15

    Oxide materials are used in numerous applications such as thermal barrier coatings, nuclear fuels, and electrical conductors and sensors, all applications where nanometer-scale stoichiometric changes can affect functional properties. Atom probe tomography can be used to characterize the precise chemical distribution of individual species and spatially quantify the oxygen to metal ratio at the nanometer scale. However, atom probe analysis of oxides can be accompanied by measurement artifacts caused by laser-material interactions. In this investigation, two technologically relevant oxide materials with the same crystal structure and an anion to cation ratio of 2.00, pure cerium oxide (CeO{sub 2}) and uranium oxide (UO{sub 2}) are studied. It was determined that electronic structure, optical properties, heat transfer properties, and oxide stability strongly affect their evaporation behavior, thus altering their measured stoichiometry, with thermal conductance and thermodynamic stability being strong factors.

  20. Organic micropollutants (OMPs) in natural waters: Oxidation by UV/H2O2 treatment and toxicity assessment.

    Science.gov (United States)

    Rozas, Oscar; Vidal, Cristiane; Baeza, Carolina; Jardim, Wilson F; Rossner, Alfred; Mansilla, Héctor D

    2016-07-01

    Organic micropollutants (OMPs) are ubiquitous in natural waters even in places where the human activity is limited. The presence of OMPs in natural water sources for human consumption encourages the evaluation of different water purification technologies to ensure water quality. In this study, the Biobío river (Chile) was selected since the watershed includes urban settlements and economic activities (i.e. agriculture, forestry) that incorporate a variety of OMPs into the aquatic environment, such as pesticides, pharmaceuticals and personal care products. Atrazine (herbicide), caffeine (psychotropic), diclofenac (anti-inflammatory) and triclosan (antimicrobial) in Biobío river water and in different stages of a drinking and two wastewater treatment plants downstream Biobío river were determined using solid phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) and electrospray ionization (ESI). Quantification of these four compounds showed concentrations in the range of 8 ± 2 to 55 ± 10 ng L(-1) in Biobío river water, 11 ± 2 to 74 ± 21 ng L(-1) in the drinking water treatment plant, and 60 ± 10 to 15,000 ± 1300 ng L(-1) in the wastewater treatment plants. Caffeine was used as an indicator of wastewater discharges. Because conventional water treatment technologies are not designed to eliminate some emerging organic pollutants, alternative treatment processes, UV and UV/H2O2, were employed. The transformation of atrazine, carbamazepine (antiepileptic), diclofenac and triclosan was investigated at laboratory scale. Both processes were tested at different UV doses and the Biobío river water matrix effects were evaluated. Initial H2O2 concentration used was 10 mg L(-1). Results showed that, the transformation profile obtained using UV/H2O2 at UV doses up to 900 mJ cm(-2), followed the trend of diclofenac > triclosan > atrazine > carbamazepine. Furthermore acute toxicity tests with Daphnia magna were carried

  1. Advanced treatment of biologically pretreated coal gasification wastewater by a novel heterogeneous Fenton oxidation process.

    Science.gov (United States)

    Zhuang, Haifeng; Han, Hongjun; Ma, Wencheng; Hou, Baolin; Jia, Shengyong; Zhao, Qian

    2015-07-01

    Sewage sludge from a biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl2 as activation agent, which was used as a support for ferric oxides to form a catalyst (FeOx/SBAC) by a simple impregnation method. The new material was then used to improve the performance of Fenton oxidation of real biologically pretreated coal gasification wastewater (CGW). The results indicated that the prepared FeOx/SBAC significantly enhanced the pollutant removal performance in the Fenton process, so that the treated wastewater was more biodegradable and less toxic. The best performance was obtained over a wide pH range from 2 to 7, temperature 30°C, 15 mg/L of H2O2 and 1g/L of catalyst, and the treated effluent concentrations of COD, total phenols, BOD5 and TOC all met the discharge limits in China. Meanwhile, on the basis of significant inhibition by a radical scavenger in the heterogeneous Fenton process as well as the evolution of FT-IR spectra of pollutant-saturated FeOx/BAC with and without H2O2, it was deduced that the catalytic activity was responsible for generating hydroxyl radicals, and a possible reaction pathway and interface mechanism were proposed. Moreover, FeOx/SBAC showed superior stability over five successive oxidation runs. Thus, heterogeneous Fenton oxidation of biologically pretreated CGW by FeOx/SBAC, with the advantages of being economical, efficient and sustainable, holds promise for engineering application.

  2. Combined Fenton oxidation and aerobic biological processes for treating a surfactant wastewater containing abundant sulfate.

    Science.gov (United States)

    Wang, Xiao-Jun; Song, Yang; Mai, Jun-Sheng

    2008-12-30

    The present study is to investigate the treatment of a surfactant wastewater containing abundant sulfate by Fenton oxidation and aerobic biological processes. The operating conditions have been optimized. Working at an initial pH value of 8, a Fe2+ dosage of 600mgL(-1) and a H2O2 dosage of 120mgL(-1), the chemical oxidation demand (COD) and linear alkylbenzene sulfonate (LAS) were decreased from 1500 and 490mgL(-1) to 230 and 23mgL(-1) after 40min of Fenton oxidation, respectively. Advanced oxidation pretreatment using Fenton reagent was very effective at enhancing the biodegradability of this kind of wastewater. The wastewater was further treated by a bio-chemical treatment process based on an immobilized biomass reactor with a hydraulic detention time (HRT) of 20h after Fenton oxidation pretreatment under the optimal operating conditions. It was found that the COD and LAS of the final effluent were less than 100 and 5mgL(-1), corresponding to a removal efficiencies of over 94% and 99%, respectively.

  3. Degradation of dibutyl phthalate (DBP) by UV-254 nm/H2O2 photochemical oxidation: kinetics and influence of various process parameters.

    Science.gov (United States)

    Wang, Dong; Duan, Xiaodi; He, Xuexiang; Dionysiou, Dionysios D

    2016-12-01

    Degradation of dibuytl phthalate (DBP), a plasticizer and also a widely distributed endocrine disruptor, by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated in this study. A significant DBP removal of 77.1 % at an initial concentration of 1.0 μM was achieved at UV fluence of 160 mJ/cm(2), initial H2O2 dosage of 1.0 mM, and pH of 7.6 ± 0.1. The DBP degradation exhibited a pseudo-first-order reaction kinetic pattern, with the rate constants linearly increasing with increasing H2O2 dosage while decreasing with increasing initial DBP concentration and pH value in a specific range. DBP destruction was significantly inhibited in the presence of alkalinity and natural organic matter (NOM), two known factors that should be taken a serious consideration of in the research and design of UV/H2O2-based AOPs. Presence of common inorganic anions (i.e., Cl(-), SO4(2-), and NO3(-)) and metal cations (i.e., Fe(3+) and Zn(2+)) had a slight impact on the degradation of DBP, although Cu(2+) could improve the degradation efficiency even at a concentration as low as 0.01 mg/L, suggesting a strong potential of applying UV/H2O2 for the removal of DBP with an environmental relevant level of copper.

  4. The hazard assessment of nanostructured CeO{sub 2}-based mixed oxides on the zebrafish Danio rerio under environmentally relevant UV-A exposure

    Energy Technology Data Exchange (ETDEWEB)

    Jemec, Anita, E-mail: anita.jemec@bf.uni-lj.si [National Institute of Chemistry, Laboratory for Environmental Sciences and Engineering, Hajdrihova 19, SI-1001 Ljubljana (Slovenia); University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, SI-1000 Ljubljana (Slovenia); Djinović, Petar; Črnivec, Ilja Gasan Osojnik; Pintar, Albin [National Institute of Chemistry, Laboratory for Environmental Sciences and Engineering, Hajdrihova 19, SI-1001 Ljubljana (Slovenia)

    2015-02-15

    The effect of nanomaterials on biota under realistic environmental conditions is an important question. However, there is still a lack of knowledge on how different illumination conditions alter the toxicity of some photocatalytic nanomaterials. We have investigated how environmentally relevant UV-A exposure (intensity 8.50 ± 0.61 W/m{sup 2}, exposure dose 9.0 J/cm{sup 2}) affected the toxicity of cerium oxide (CeO{sub 2})-based nanostructured materials to the early-life stages of zebrafish Danio rerio. Pure cerium oxide (CeO{sub 2}), copper–cerium (CuO–CeO{sub 2}) (with a nominal 10, 15 and 20 mol.% CuO content), cerium–zirconium (CeO{sub 2}–ZrO{sub 2}) and nickel and cobalt (Ni–Co) deposited over CeO{sub 2}–ZrO{sub 2} were tested. It was found that under both illumination regimes, none of the tested materials affected the normal development or induced mortality of zebrafish early-life stages up to 100 mg/L. Only in the case of CuO–CeO{sub 2}, the growth of larvae was decreased (96 h LOEC values for CuCe10, CuCe15 and CuCe20 were 50, 50 and 10 mg/L, respectively). To conclude, CeO{sub 2}-based nanostructured materials are not severely toxic to zebrafish and environmentally relevant UV-A exposure does not enhance their toxicity. - Highlights: • CeO{sub 2}–ZrO{sub 2} nanomaterials and pure CeO{sub 2} (up to 100 mg/L) were not harmful to zebrafish. • Only CuO modified CeO{sub 2} affected the growth of zebrafish larvae. • UV-A radiation did not enhance the toxicity of tested nanomaterials.

  5. Biological markers of oxidative stress: Applications to cardiovascular research and practice

    Directory of Open Access Journals (Sweden)

    Edwin Ho

    2013-01-01

    Full Text Available Oxidative stress is a common mediator in pathogenicity of established cardiovascular risk factors. Furthermore, it likely mediates effects of emerging, less well-defined variables that contribute to residual risk not explained by traditional factors. Functional oxidative modifications of cellular proteins, both reversible and irreversible, are a causal step in cellular dysfunction. Identifying markers of oxidative stress has been the focus of many researchers as they have the potential to act as an “integrator” of a multitude of processes that drive cardiovascular pathobiology. One of the major challenges is the accurate quantification of reactive oxygen species with very short half-life. Redox-sensitive proteins with important cellular functions are confined to signalling microdomains in cardiovascular cells and are not readily available for quantification. A popular approach is the measurement of stable by-products modified under conditions of oxidative stress that have entered the circulation. However, these may not accurately reflect redox stress at the cell/tissue level. Many of these modifications are “functionally silent”. Functional significance of the oxidative modifications enhances their validity as a proposed biological marker of cardiovascular disease, and is the strength of the redox cysteine modifications such as glutathionylation. We review selected biomarkers of oxidative stress that show promise in cardiovascular medicine, as well as new methodologies for high-throughput measurement in research and clinical settings. Although associated with disease severity, further studies are required to examine the utility of the most promising oxidative biomarkers to predict prognosis or response to treatment.

  6. Integration of advanced oxidation technologies and biological processes: recent developments, trends, and advances.

    Science.gov (United States)

    Tabrizi, Gelareh Bankian; Mehrvar, Mehrab

    2004-01-01

    The greatest challenge of today's wastewater treatment technology is to optimize the use of biological and chemical wastewater treatment processes. The choice of the process and/or integration of the processes depend strongly on the wastewater characteristics, concentrations, and the desired efficiencies. It has been observed by many investigators that the coupling of a bioreactor and advanced oxidation processes (AOPs) could reduce the final concentrations of the effluent to the desired values. However, optimizing the total cost of the treatment is a challenge, as AOPs are much more expensive than biological processes alone. Therefore, an appropriate design should not only consider the ability of this coupling to reduce the concentration of organic pollutants, but also try to obtain the desired results in a cost effective process. To consider the total cost of the treatment, the residence time in biological and photochemical reactors, the kinetic rates, and the capital and operating costs of the reactors play significant roles. In this study, recent developments and trends (1996-2003) on the integration of photochemical and biological processes for the degradation of problematic pollutants in wastewater have been reviewed. The conditions to get the optimum results from this integration have also been considered. In most of the studies, it has been shown that the integrated processes were more efficient than individual processes. However, slight changes in the configuration of the reactors, temperature, pH, treatment time, concentration of the oxidants, and microorganism's colonies could lead to a great deviation in results. It has also been demonstrated that the treatment cost in both reactors is a function of time, which changes by the flow rate. The minimum cost in the coupling of the processes cannot be achieved unless considering the best treatment time in chemical and biological reactors individually.

  7. Dynamics of cover, UV-protective pigments, and quantum yield in biological soil crust communities of an undisturbed Mojave Desert shrubland

    Science.gov (United States)

    Belnap, J.; Phillips, S.L.; Smith, S.D.

    2007-01-01

    Biological soil crusts are an integral part of dryland ecosystems. We monitored the cover of lichens and mosses, cyanobacterial biomass, concentrations of UV-protective pigments in both free-living and lichenized cyanobacteria, and quantum yield in the soil lichen species Collema in an undisturbed Mojave Desert shrubland. During our sampling time, the site received historically high and low levels of precipitation, whereas temperatures were close to normal. Lichen cover, dominated by Collema tenax and C. coccophorum, and moss cover, dominated by Syntrichia caninervis, responded to both increases and decreases in precipitation. This finding for Collema spp. at a hot Mojave Desert site is in contrast to a similar study conducted at a cool desert site on the Colorado Plateau in SE Utah, USA, where Collema spp. cover dropped in response to elevated temperatures, but did not respond to changes in rainfall. The concentrations of UV-protective pigments in free-living cyanobacteria at the Mojave Desert site were also strongly and positively related to rainfall received between sampling times (R2 values ranged from 0.78 to 0.99). However, pigment levels in the lichenized cyanobacteria showed little correlation with rainfall. Quantum yield in Collema spp. was closely correlated with rainfall. Climate models in this region predict a 3.5-4.0 ??C rise in temperature and a 15-20% decline in winter precipitation by 2099. Based on our data, this rise in temperature is unlikely to have a strong effect on the dominant species of the soil crusts. However, the predicted drop in precipitation will likely lead to a decrease in soil lichen and moss cover, and high stress or mortality in soil cyanobacteria as levels of UV-protective pigments decline. In addition, surface-disturbing activities (e.g., recreation, military activities, fire) are rapidly increasing in the Mojave Desert, and these disturbances quickly remove soil lichens and mosses. These stresses combined are likely to lead to

  8. Biologically Synthesized Gold Nanoparticles Ameliorate Cold and Heat Stress-Induced Oxidative Stress in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Xi-Feng Zhang

    2016-06-01

    Full Text Available Due to their unique physical, chemical, and optical properties, gold nanoparticles (AuNPs have recently attracted much interest in the field of nanomedicine, especially in the areas of cancer diagnosis and photothermal therapy. Because of the enormous potential of these nanoparticles, various physical, chemical, and biological methods have been adopted for their synthesis. Synthetic antioxidants are dangerous to human health. Thus, the search for effective, nontoxic natural compounds with effective antioxidative properties is essential. Although AuNPs have been studied for use in various biological applications, exploration of AuNPs as antioxidants capable of inhibiting oxidative stress induced by heat and cold stress is still warranted. Therefore, one goal of our study was to produce biocompatible AuNPs using biological methods that are simple, nontoxic, biocompatible, and environmentally friendly. Next, we aimed to assess the antioxidative effect of AuNPs against oxidative stress induced by cold and heat in Escherichia coli, which is a suitable model for stress responses involving AuNPs. The response of aerobically grown E. coli cells to cold and heat stress was found to be similar to the oxidative stress response. Upon exposure to cold and heat stress, the viability and metabolic activity of E. coli was significantly reduced compared to the control. In addition, levels of reactive oxygen species (ROS and malondialdehyde (MDA and leakage of proteins and sugars were significantly elevated, and the levels of lactate dehydrogenase activity (LDH and adenosine triphosphate (ATP significantly lowered compared to in the control. Concomitantly, AuNPs ameliorated cold and heat-induced oxidative stress responses by increasing the expression of antioxidants, including glutathione (GSH, glutathione S-transferase (GST, super oxide dismutase (SOD, and catalase (CAT. These consistent physiology and biochemical data suggest that AuNPs can ameliorate cold and

  9. Acquisition of pro-oxidant activity of fALS-linked SOD1 mutants as revealed using circular dichroism and UV-resonance Raman spectroscopy

    Science.gov (United States)

    Fujimaki, Nobuhiro; Nishiya, Ken; Miura, Takashi; Nakabayashi, Takakazu

    2016-11-01

    The acquisition of pro-oxidant activity of the mutated form of human Cu, Zn-superoxide dismutase (SOD1) has been investigated to clarify the relationship between mutations in SOD1 and the pathogenesis of amyotrophic lateral sclerosis (ALS). Ala4 → Val (A4V) and Gly93 → Ala (G93A) mutants, which are representative ALS-linked SOD1 mutants, have been found to exhibit both the denaturation and the gain of pro-oxidant activity after incubation in the apo-form at a physiological condition of 37 °C and pH 7.4 and the rebinding of Cu2+. These characteristics are similar to those previously reported for the His43 → Arg (H43R) mutant. UV-resonance Raman spectra indicated that the coordination structure of the Cu-binding site catalyzing the oxidation reaction is the same among the denatured A4V, G93A, and H43R. Since wild-type SOD1 does not exhibit the denaturation in its apo-form at 37 °C and pH 7.4, the instability of the protein structure due to mutation can be considered as a significant factor that induces the denaturation and the subsequent pro-oxidant activity.

  10. Accurate electronic and chemical properties of 3d transition metal oxides using a calculated linear response U and a DFT + U(V) method.

    Science.gov (United States)

    Xu, Zhongnan; Joshi, Yogesh V; Raman, Sumathy; Kitchin, John R

    2015-04-14

    We validate the usage of the calculated, linear response Hubbard U for evaluating accurate electronic and chemical properties of bulk 3d transition metal oxides. We find calculated values of U lead to improved band gaps. For the evaluation of accurate reaction energies, we first identify and eliminate contributions to the reaction energies of bulk systems due only to changes in U and construct a thermodynamic cycle that references the total energies of unique U systems to a common point using a DFT + U(V) method, which we recast from a recently introduced DFT + U(R) method for molecular systems. We then introduce a semi-empirical method based on weighted DFT/DFT + U cohesive energies to calculate bulk oxidation energies of transition metal oxides using density functional theory and linear response calculated U values. We validate this method by calculating 14 reactions energies involving V, Cr, Mn, Fe, and Co oxides. We find up to an 85% reduction of the mean average error (MAE) compared to energies calculated with the Perdew-Burke-Ernzerhof functional. When our method is compared with DFT + U with empirically derived U values and the HSE06 hybrid functional, we find up to 65% and 39% reductions in the MAE, respectively.

  11. A Modified Oxidation Ditch with Additional Internal Anoxic Zones for Enhanced Biological Nutrient Removal

    Institute of Scientific and Technical Information of China (English)

    LIU Wei; YANG Dianhai; XU Li; SHEN Changming

    2013-01-01

    A novel modified pilot scale anaerobic oxidation ditch with additional internal anoxic zones was operated experimentally,aiming to study the improvement of biological nitrogen and phosphorus removal and the effect of enhanced denitrifying phosphorus removal in the process.Under all experimental conditions,the anaerobic-oxidation ditch with additional internal anoxic zones and an internal recycle ratio of 200% had the highest nutrient removal efficiency.The effluent NH+4-N,total nitrogen(TN),PO34--P and total phosphorus(TP)contents were 1.2 mg·L-1,13 mg·L-1,0.3 mg·L-1 and 0.4 mg·L-1,respectively,all met the discharge standards in China.The TN and TP removal efficiencies were remarkably improved from 37% and 50% to 65% and 88% with the presence of additional internal anoxic zones and internal recycle ratio of 200%.The results indicated that additional internal anoxic zones can optimize the utilization of available carbon source from the anaerobic outflow for denitrification.It was also found that phosphorus removal via the denitrification process was stimulated in the additional internal anoxic zones,which was beneficial for biological nitrogen and phosphorus removal when treating wastewater with a limited carbon source.However,an excess internal recycle would cause nitrite to accumulate in the system.This seems to be harmful to biological phosphorus removal.

  12. Effect of sulfur compounds on biological reduction of nitric oxide in aqueous Fe(II)EDTA2- solutions

    NARCIS (Netherlands)

    Manconi, I.; Maas, van der P.M.F.; Lens, P.N.L.

    2006-01-01

    Biological reduction of nitric oxide (NO) in aqueous solutions of EDTA chelated Fe(II) is one of the main steps in the BioDeNOx process, a novel bioprocess for the removal of nitrogen oxides (NOx) from polluted gas streams. Since NOx contaminated gases usually also contain sulfurous pollutants, the

  13. Effect of iron oxide and gold nanoparticles on bacterial growth leading towards biological application

    Directory of Open Access Journals (Sweden)

    Bandyopadhyay Arghya

    2011-08-01

    Full Text Available Abstract Background Nanoparticle-metal oxide and gold represents a new class of important materials that are increasingly being developed for use in research and health related activities. The biological system being extremely critical requires the fundamental understanding on the influence of inorganic nanoparticles on cellular growth and functions. Our study was aimed to find out the effect of iron oxide (Fe3O4, gold (Au nanoparticles on cellular growth of Escherichia coli (E. coli and also try to channelize the obtained result by functionalizing the Au nanoparticle for further biological applications. Result Fe3O4 and Au nanoparticles were prepared and characterized using Transmission electron microscopy (TEM and Dynamic Light Scattering (DLS. Preliminary growth analysis data suggest that the nanoparticles of iron oxide have an inhibitory effect on E. coli in a concentration dependant manner, whereas the gold nanoparticle directly showed no such activity. However the phase contrast microscopic study clearly demonstrated that the effect of both Fe3O4 and Au nanoparticle extended up to the level of cell division which was evident as the abrupt increase in bacterial cell length. The incorporation of gold nanoparticle by bacterial cell was also observed during microscopic analysis based on which glutathione functionalized gold nanoparticle was prepared and used as a vector for plasmid DNA transport within bacterial cell. Conclusion Altogether the study suggests that there is metal nanoparticle-bacteria interaction at the cellular level that can be utilized for beneficial biological application but significantly it also posses potential to produce ecotoxicity, challenging the ecofriendly nature of nanoparticles.

  14. The ex vivo and in vivo biological performances of graphene oxide and the impact of surfactant on graphene oxide's biocompatibility

    Institute of Scientific and Technical Information of China (English)

    Guangbo Qu; Xiaoyan Wang; Qian Liu; Rui Liu; Nuoya Yin; Juan Ma; Liqun Chen

    2013-01-01

    Graphene oxide (GO) displays promising properties for biomedical applications including drug delivery and cancer therapeutics.However,GO exposure also raises safety concerns such as potential side effects on health.Here,the biological effects of GO suspended in phosphate buffered saline (PBS) with or without 1% nonionic surfactant Tween 80 were investigated.Based on the ex vivo experiments,Tween 80 significantly affected the interaction between GO and peripheral blood from mice.GO suspension in PBS tended to provoke the aggregation of diluted blood cells,which could be prevented by the addition of Tween 80.After intravenous administration,GO suspension with or without 1% Tween 80 was quickly eliminated by the mononuclear phagocyte system.Nevertheless,GO suspension without Tween 80 showed greater accumulation in lungs than that containing 1% Tween 80.In contrast,less GO was found in livers for GO suspension compared to Tween 80 assisted GO suspension.Organs including hearts,livers,lungs,spleens,kidneys,brains,and testes did not reveal histological alterations.The indexes of peripheral blood showed no change upon GO exposure.Our results together demonstrated that Tween 80 could greatly alter GO's biological performance and determine the pattern of its biodistribution in mice.

  15. Sulfur-centered reactive intermediates derived from the oxidation of sulfur compounds of biological interest

    Energy Technology Data Exchange (ETDEWEB)

    Abedinzadeh, Z. [Lab. de Chimie Physique, UMR, Univ. Rene Descartes, Paris (France)

    2001-02-01

    Sulphur compounds play a central role in the structure and activity of many vital systems. In the living cell, sulfur constitutes an essential part of the defense against oxidative damage and is transformed into a variety of sulfur free radical species. Many studies of the chemistry of sulfur-centered radicals using pulse radiolysis and photolysis techniques to detect and measure the kinetics of these radicals have been published and reviewed. This paper discusses the present state of research on the formation and reactivity of certain sulfur-centered radicals [RS{sup .}, RSS{sup .}, RS{sup .+}, (RSSR){sup .+}] and their implications for biological systems. (author)

  16. Antibiotic abatement in different advanced oxidation processes coupled with a biological sequencing batch biofilm reactor

    Energy Technology Data Exchange (ETDEWEB)

    Esplugas, M.; Gonzalez, O.; Benito, J.; Sans, C.

    2009-07-01

    During the last decade, the lack of fresh water is becoming a major concern. Recently, the present of recalcitrant products such as pharmaceuticals has caused a special interest due to their undefined environmental impact. Among these antibiotics are one of the numerous recalcitrant pollutants present in surface waters that might not be completely removed in the biological stage of sewage treatment plants because of their antibacterial nature. Advanced Oxidation Processes (AOPs) have proved to be highly efficient for the degradation of most organic pollutants in wastewaters. (Author)

  17. Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe

    Science.gov (United States)

    Huffman, J. A.; Treutlein, B.; Pöschl, U.

    2010-04-01

    Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure Fluorescent Biological Aerosol Particles (FBAPs), which provide an estimate of viable bioaerosol particles and can be regarded as an approximate lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (particles (1-20 μm). Averaged over the four-month measurement period (August-December 2006), the mean number concentration of coarse FBAPs was ~3×10-2 cm-3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1μg m-3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10-2 cm-3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle (24-h) with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical analyses of PBAPs in aerosol

  18. Report: Bioconversion of agriculture waste to lysine with UV mutated strain of brevibacterium flavum and its biological evaluation in broiler chicks.

    Science.gov (United States)

    Tabassum, Alia; Hashmi, Abu Saeed; Masood, Faiza; Iqbal, Muhammad Aamir; Tayyab, Muhammad; Nawab, Amber; Nadeem, Asif; Sadeghi, Zahra; Mahmood, Adeel

    2015-07-01

    Lysine executes imperative structural and functional roles in body and its supplementation in diet beneficial to prevent the escalating threat of protein deficiency. The physical mutagenesis offers new fascinating avenues of research for overproduction of lysine through surplus carbohydrate containing agriculture waste especially in developing countries. The current study was aimed to investigate the potential of UV mutated strain of Brevibacterium flavum at 254 nm for lysine production. The physical and nutritional parameters were optimized and maximum lysine production was observed with molasses (4% substrate water ratio). Moreover, supplementation of culture medium with metal cations (i.e. 0.4% CaSO₄, 0.3% NaCl, 0.3% KH₂PO₄, 0.4% MgSO₄, and 0.2% (NH₄) ₂SO₄w/v) together with 0.75% v/v corn steep liquor significantly enhanced the lysine production up to 26.71 ± 0.31 g/L. Though, concentrations of urea, ammonium nitrate and yeast sludge did not exhibit any profound effect on lysine production. Biological evaluation of lysine enriched biomass in terms of weight gain and feed conversion ratio reflected non-significant difference for experimental and control (+ve) groups. Conclusively, lysine produced in the form of biomass was compatible to market lysine in its effectiveness and have potential to utilize at commercial scale.

  19. Metal oxide nanostructures synthesized on flexible and solid substrates and used for catalysts, UV detectors, and chemical sensors

    Science.gov (United States)

    Willander, Magnus; Sadollahkhani, Azar; Echresh, Ahmad; Nur, Omer

    2014-03-01

    In this paper we demonstrate the visibility of the low temperature chemical synthesis for developing device quality material grown on flexible and solid substrates. Both colorimetric sensors and UV photodetectors will be presented. The colorimetric sensors developed on paper were demonstrated for heavy metal detection, in particular for detecting copper ions in aqueous solutions. The demonstrated colorimetric copper ion sensors developed here are based on ZnO@ZnS core-shell nanoparticles (CSNPs). These sensors demonstrated an excellent low detection limit of less than 1 ppm of copper ions. Further the colorimetric sensors operate efficiently in a wide pH range between 4 and 11, and even in turbulent water. The CSNPs were additionally used as efficient photocatalytic degradation element and were found to be more efficient than pure ZnO nanoparticles (NPs). Also p-NiO/n-ZnO thin film/nanorods pn junctions were synthesized by a two-step synthesis process and were found to act as efficient UV photodetectors. Additionally we show the effect of the morphology of different CuO nanostructures on the efficiency of photo catalytic degradation of Congo red organic dye.

  20. Treatment of an actual slaughterhouse wastewater by integration of biological and advanced oxidation processes: Modeling, optimization, and cost-effectiveness analysis.

    Science.gov (United States)

    Bustillo-Lecompte, Ciro Fernando; Mehrvar, Mehrab

    2016-11-01

    Biological and advanced oxidation processes are combined to treat an actual slaughterhouse wastewater (SWW) by a sequence of an anaerobic baffled reactor, an aerobic activated sludge reactor, and a UV/H2O2 photoreactor with recycle in continuous mode at laboratory scale. In the first part of this study, quadratic modeling along with response surface methodology are used for the statistical analysis and optimization of the combined process. The effects of the influent total organic carbon (TOC) concentration, the flow rate, the pH, the inlet H2O2 concentration, and their interaction on the overall treatment efficiency, CH4 yield, and H2O2 residual in the effluent of the photoreactor are investigated. The models are validated at different operating conditions using experimental data. Maximum TOC and total nitrogen (TN) removals of 91.29 and 86.05%, respectively, maximum CH4 yield of 55.72%, and minimum H2O2 residual of 1.45% in the photoreactor effluent were found at optimal operating conditions. In the second part of this study, continuous distribution kinetics is applied to establish a mathematical model for the degradation of SWW as a function of time. The agreement between model predictions and experimental values indicates that the proposed model could describe the performance of the combined anaerobic-aerobic-UV/H2O2 processes for the treatment of SWW. In the final part of the study, the optimized combined anaerobic-aerobic-UV/H2O2 processes with recycle were evaluated using a cost-effectiveness analysis to minimize the retention time, the electrical energy consumption, and the overall incurred treatment costs required for the efficient treatment of slaughterhouse wastewater effluents.

  1. Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination-A review

    Energy Technology Data Exchange (ETDEWEB)

    Oller, I., E-mail: isabel.oller@psa.es [Plataforma Solar de Almeria (CIEMAT), Carretera Senes, Km 4. 04200 Tabernas (Almeria) (Spain); Malato, S. [Plataforma Solar de Almeria (CIEMAT), Carretera Senes, Km 4. 04200 Tabernas (Almeria) (Spain); Sanchez-Perez, J.A. [Department of Chemical Engineering, University of Almeria, Crta de Sacramento s/n, 04120 Almeria (Spain)

    2011-09-15

    Nowadays there is a continuously increasing worldwide concern for development of alternative water reuse technologies, mainly focused on agriculture and industry. In this context, Advanced Oxidation Processes (AOPs) are considered a highly competitive water treatment technology for the removal of those organic pollutants not treatable by conventional techniques due to their high chemical stability and/or low biodegradability. Although chemical oxidation for complete mineralization is usually expensive, its combination with a biological treatment is widely reported to reduce operating costs. This paper reviews recent research combining AOPs (as a pre-treatment or post-treatment stage) and bioremediation technologies for the decontamination of a wide range of synthetic and real industrial wastewater. Special emphasis is also placed on recent studies and large-scale combination schemes developed in Mediterranean countries for non-biodegradable wastewater treatment and reuse. The main conclusions arrived at from the overall assessment of the literature are that more work needs to be done on degradation kinetics and reactor modeling of the combined process, and also dynamics of the initial attack on primary contaminants and intermediate species generation. Furthermore, better economic models must be developed to estimate how the cost of this combined process varies with specific industrial wastewater characteristics, the overall decontamination efficiency and the relative cost of the AOP versus biological treatment.

  2. Oxidative Damage and Mutagenic Potency of Fast Neutron and UV-B Radiation in Pollen Mother Cells and Seed Yield of Vicia faba L.

    Directory of Open Access Journals (Sweden)

    Ekram Abdel Haliem

    2013-01-01

    Full Text Available In recent years, there has been a great deal of attention toward free radicals, reactive oxygen species (ROS generated by exposure of crop plant cells to physical radiations. Henceforth, the current study was planned to compare oxidative stress and mutagenic potential of different irradiation doses of fast neutron (FN and UV-B on meiotic-pollen mother cells (PMCs, pollen grains (PGs and seeds yielded from irradiated faba beans seedlings. On the cytogenetic level, each irradiation type had special interference with DNA of PMC and exhibited wide range of mutagenic action on the frequency and type of chromosomal anomalies, fertility of PGs and seed yield productivity based on the irradiation exposure dose and radiation sensitivity of faba bean plants compared with un-irradiated ones. On the molecular level, SDS-PAGE and RPAD-PCR analyses of seeds yielded from irradiated seedlings exhibited distinctive polymorphisms based on size, intensity, appearance, and disappearance of polypeptides bands compared with un-irradiated ones. The total values of protein and DNA polymorphisms reached 88% and 90.80% respectively. The neutron fluency (2.3 × 106 n/cm2 and UV-B dose for 1 hr were recorded as bio-positive effects. The present study proved that genetic variations revealed by cytogenetic test could be supported by gene expression (alterations in RAPD and protein profiles.

  3. Photocatalytic decomposition of selected estrogens and their estrogenic activity by UV-LED irradiated TiO2 immobilized on porous titanium sheets via thermal-chemical oxidation.

    Science.gov (United States)

    Arlos, Maricor J; Liang, Robert; Hatat-Fraile, Melisa M; Bragg, Leslie M; Zhou, Norman Y; Servos, Mark R; Andrews, Susan A

    2016-11-15

    The removal of endocrine disrupting compounds (EDCs) remains a big challenge in water treatment. Risks associated with these compounds are not clearly defined and it is important that the water industry has additional options to increase the resiliency of water treatment systems. Titanium dioxide (TiO2) has potential applications for the removal of EDCs from water. TiO2 has been immobilized on supports using a variety of synthesis methods to increase its feasibility for water treatment. In this study, we immobilized TiO2 through the thermal-chemical oxidation of porous titania sheets. The efficiency of the material to degrade target EDCs under UV-LED irradiation was examined under a wide range of pH conditions. A yeast-estrogen screen assay was used to complement chemical analysis in assessing removal efficiency. All compounds but 17β-estradiol were degraded and followed a pseudo first-order kinetics at all pH conditions tested, with pH 4 and pH 11 showing the most and the least efficient treatments respectively. In addition, the total estrogenic activity was substantially reduced even with the inefficient degradation of 17β-estradiol. Additional studies will be required to optimize different treatment conditions, UV-LED configurations, and membrane fouling mitigation measures to make this technology a more viable option for water treatment.

  4. Synthesis and photocatalytic performance of reduced graphene oxide-TiO2 nanocomposites for orange II degradation under UV light irradiation.

    Science.gov (United States)

    Li, Tengfei; Wang, Tiecheng; Qu, Guangzhou; Liang, Dongli; Hu, Shibin

    2017-03-30

    To enhance the photocatalytic activity of TiO2, reduced graphene oxide-TiO2 (RGO-TiO2) composites with sandwich-like structure were synthesized using a simple solvothermal method. The morphology, crystalline information, and structural property of the photocatalyst were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transmission infrared spectroscopy. The photocatalytic performances of the RGO-TiO2 composites were evaluated by the degradation of orange II (AO7) in water under UV light irradiation. The results showed that the RGO-TiO2 composites exhibited much higher photocatalytic activity than TiO2 and that the removal efficiency of AO7 could reach above 95% only after 20 min of UV light irradiation under the optimum condition. The improved photocatalytic activity might be attributed to the improved charge transfer and significant separation of the photoinduced electrons and holes in the presence of a two-dimensional graphene network. The results of recycling experiments show that RGO-TiO2 composites have a high photostability, which is expected in the practical application. Radical trapping experiments indicated that ·OH plays a crucial role in the process of AO7 degradation.

  5. UV absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 between 210 and 350 K and the atmospheric implications

    Directory of Open Access Journals (Sweden)

    C. H. Jackman

    2010-07-01

    Full Text Available Absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 are reported at five atomic UV lines (184.95, 202.548, 206.200, 213.857, and 228.8 nm at temperatures in the range 210–350 K. In addition, UV absorption spectra of CCl4 are reported between 200–235 nm as a function of temperature (225–350 K. The results from this work are critically compared with results from earlier studies. For N2O, the present results are in good agreement with the current JPL recommendation enabling a reduction in the estimated uncertainty in the N2O atmospheric photolysis rate. For CCl4, the present cross section results are systematically greater than the current recommendation at the reduced temperatures most relevant to stratospheric photolysis. The new cross sections result in a 5–7% increase in the modeled CCl4 photolysis loss, and a slight decrease in the stratospheric lifetime, from 51 to 50 years, for present day conditions. The corresponding changes in modeled inorganic chlorine and ozone in the stratosphere are quite small. A CCl4 cross section parameterization for use in atmospheric model calculations is presented.

  6. UV absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 between 210 and 350 K and the atmospheric implications

    Directory of Open Access Journals (Sweden)

    C. H. Jackman

    2010-04-01

    Full Text Available Absorption cross sections of nitrous oxide (N2O and carbon tetrachloride (CCl4 are reported at five atomic UV lines (184.95, 202.548, 206.200, 213.857, and 228.8 nm at temperatures in the range 210–350 K. In addition, UV absorption spectra of CCl4 are reported between 200–235 nm as a function of temperature (225–350 K. The results from this work are critically compared with results from earlier studies. For N2O, the present results are in good agreement with the current JPL recommendation enabling a reduction in the estimated uncertainty in the N2O atmospheric photolysis rate. For CCl4, the present cross section results are systematically greater than the current recommendation at the reduced temperatures most relevant to stratospheric photolysis. The new cross sections result in a 5–7% increase in the modeled CCl4 photolysis loss, and a slight decrease in the stratospheric lifetime, from 51 to 50 years, for present day conditions. The corresponding changes in modeled inorganic chlorine and ozone in the stratosphere are quite small. A CCl4 cross section parameterization for use in atmospheric model calculations is presented.

  7. Selective Alcohol Oxidation by a Copper TEMPO Catalyst: Mechanistic Insights by Simultaneously Coupled Operando EPR/UV-Vis/ATR-IR Spectroscopy.

    Science.gov (United States)

    Rabeah, Jabor; Bentrup, Ursula; Stößer, Reinhard; Brückner, Angelika

    2015-09-28

    The first coupled operando EPR/UV-Vis/ATR-IR spectroscopy setup for mechanistic studies of gas-liquid phase reactions is presented and exemplarily applied to the well-known copper/TEMPO-catalyzed (TEMPO=(2,2,6,6-tetramethylpiperidin-1-yl)oxyl) oxidation of benzyl alcohol. In contrast to previous proposals, no direct redox reaction between TEMPO and Cu(I) /Cu(II) has been detected. Instead, the role of TEMPO is postulated to be the stabilization of a (bpy)(NMI)Cu(II) -O2 (⋅-) -TEMPO (bpy=2,2'-bipyridine, NMI=N-methylimidazole) intermediate formed by electron transfer from Cu(I) to molecular O2 .

  8. Treatment of pharmaceutical wastewater using interior micro-electrolysis/Fenton oxidation-coagulation and biological degradation.

    Science.gov (United States)

    Xu, Xiaoyi; Cheng, Yao; Zhang, Tingting; Ji, Fangying; Xu, Xuan

    2016-06-01

    The synthesis of steroid hormones produces wastewater that is difficult to manage and characterize due to its complex components and high levels of toxicity and bio-refractory compounds. In this work, interior micro-electrolysis (IME) and Fenton oxidation-coagulation (FOC) were investigated as wastewater pretreatment processes in combination with biological treatments using a hydrolysis acidification unit (HA) and two-stage biological contact oxidation (BCO) in laboratory and field experiments. In laboratory experiments with an average initial COD load of about 15,000 mg/L, pH of 4, Fe-C/water (V/V) ratio of 1:1, air/water ratio of 10, and reaction time of 180 min, IME achieved a COD removal efficiency of 31.8% and a 1.7-fold increase in the BOD5/COD (B/C) ratio of wastewater. The Fe(2+) concentration of 458.5 mg/L in the IME effluent meets the requirements of the Fenton oxidation (FO) process. FOC further reduced the COD with an efficiency of 30.1%, and the B/C ratio of the wastewater reached 0.59. Excitation-emission matrix (EEM) analysis showed that complex higher molecular weight organic compounds in the wastewater were degraded after the pretreatment process. In addition, a field experiment with a continuous flow of 96 m(3)/d was conducted for over 90 d. The combined process system operated steadily, though the Fe-C fillings should be soaked in a sulfuric acid solution (5‰) for 12 h to recover activity every two weeks. The COD and BOD5 concentrations in the final effluent were less than 90 mg/L and 15 mg/L, respectively.

  9. Nonenzymatic Reactions above Phospholipid Surfaces of Biological Membranes: Reactivity of Phospholipids and Their Oxidation Derivatives.

    Science.gov (United States)

    Solís-Calero, Christian; Ortega-Castro, Joaquín; Frau, Juan; Muñoz, Francisco

    2015-01-01

    Phospholipids play multiple and essential roles in cells, as components of biological membranes. Although phospholipid bilayers provide the supporting matrix and surface for many enzymatic reactions, their inherent reactivity and possible catalytic role have not been highlighted. As other biomolecules, phospholipids are frequent targets of nonenzymatic modifications by reactive substances including oxidants and glycating agents which conduct to the formation of advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs). There are some theoretical studies about the mechanisms of reactions related to these processes on phosphatidylethanolamine surfaces, which hypothesize that cell membrane phospholipids surface environment could enhance some reactions through a catalyst effect. On the other hand, the phospholipid bilayers are susceptible to oxidative damage by oxidant agents as reactive oxygen species (ROS). Molecular dynamics simulations performed on phospholipid bilayers models, which include modified phospholipids by these reactions and subsequent reactions that conduct to formation of ALEs and AGEs, have revealed changes in the molecular interactions and biophysical properties of these bilayers as consequence of these reactions. Then, more studies are desirable which could correlate the biophysics of modified phospholipids with metabolism in processes such as aging and diseases such as diabetes, atherosclerosis, and Alzheimer's disease.

  10. Experimental study on the pre-treatment of flotation wastewater by UV/Fenton oxidation-coagulation process%UV/Fenton -混凝法对浮选废水预处理研究

    Institute of Scientific and Technical Information of China (English)

    吕春玲; 王莹; 刘强

    2015-01-01

    试验考察了UV/Fenton法和CCG788/UV/Fenton法对浮选废水进行预氧化后,废水中COD去除效果的影响因素。其结果表明:UV/Fenton 法处理效果明显优于普通 Fenton 法,而CCG788的加入提高了 UV/Fenton 体系对紫外光的利用率,不仅氧化效果更好,还可以促进UV/Fenton氧化反应的进行,缩短反应时间。在前述试验结果基础上,对CCG788/UV/Fenton法处理后的浮选废水投加CCG158进行了二次氧化,COD去除率可提高到87%,并缩短了总反应时长。%Pre-oxidation of flotation wastewater by UV/Fenton and CCG 788/UV/Fenton process was exploredin terms of the influence factors on COD removal.The experiment results show that UV/Fenton oxidation process is much more effective for the pre-treatment of flotation wastewater than Fenton oxidation process.In addition,the introduction of CCG788 into UV/Fenton system improves the utilization of ultraviolet ray( UV) and removal rates of COD,as well as promotes oxidation reaction and shortens the reaction time.Furthermore,the total removal rate of COD can reach 87 %by secondary oxidation of CCG788/UV/Fenton flotation wastewater with CCG158,and the reaction time is shortened.

  11. Reduction of graphene oxide by resveratrol: a novel and simple biological method for the synthesis of an effective anticancer nanotherapeutic molecule

    Directory of Open Access Journals (Sweden)

    Gurunathan S

    2015-04-01

    Full Text Available Sangiliyandi Gurunathan, Jae Woong Han, Eun Su Kim, Jung Hyun Park, Jin-Hoi Kim Department of Animal Biotechnology, Konkuk University, Seoul, Republic of Korea Objective: Graphene represents a monolayer or a few layers of sp2-bonded carbon atoms with a honeycomb lattice structure. Unique physical, chemical, and biological properties of graphene have attracted great interest in various fields including electronics, energy, material industry, and medicine, where it is used for tissue engineering and scaffolding, drug delivery, and as an antibacterial and anticancer agent. However, graphene cytotoxicity for ovarian cancer cells is still not fully investigated. The objective of this study was to synthesize graphene using a natural polyphenol compound resveratrol and to investigate its toxicity for ovarian cancer cells.Methods: The successful reduction of graphene oxide (GO to graphene was confirmed by UV-vis and Fourier transform infrared spectroscopy. Dynamic light scattering and scanning electron microscopy were employed to evaluate particle size and surface morphology of GO and resveratrol-reduced GO (RES-rGO. Raman spectroscopy was used to determine the removal of oxygen-containing functional groups from GO surface and to ensure the formation of graphene. We also performed a comprehensive analysis of GO and RES-rGO cytotoxicity by examining the morphology, viability, membrane integrity, activation of caspase-3, apoptosis, and alkaline phosphatase activity of ovarian cancer cells.Results: The results also show that resveratrol effectively reduced GO to graphene and the properties of RES-rGO nanosheets were comparable to those of chemically reduced graphene. Biological experiments showed that GO and RES-rGO caused a dose-dependent membrane leakage and oxidative stress in cancer cells, and reduced their viability via apoptosis confirmed by the upregulation of apoptosis executioner caspase-3.Conclusion: Our data demonstrate a single, simple green

  12. 混凝-催化氧化-水解酸化-生物接触氧化法处理染料废水的中试研究%Pilot scale study on dyeing wastewater treatment with coagulation/catalytic oxidation/hydrolytic acidification/biological contact oxidation

    Institute of Scientific and Technical Information of China (English)

    马宏瑞; 任健; 王保和

    2009-01-01

    采用混凝-催化氧化-水解酸化-生物接触氧化法处理高浓度难降解分散染料废水.比较分析了O_3、UV/TiO_2/O_3,UV/O_3/H_2O_23种高级氧化法的处理效果.结果表明,UV/TiO_2/O_3对废水COD和色度有较高的去除率.可明显改善废水的可生化性,废水的BOD_5/COD由0.05~0.07升高至0.42~0.46.在混凝沉淀单元HRT为1.5 h.催化氧化单元(UV/TiO_2/O_3)HRT为3.0 h,水解酸化HRT为10.0 h,生物接触氧化HRT为10.0 h的最佳条件下,该组合工艺对废水COD和色度总的去除率分别可达95.0%、99.5%.%The synthetic method of using coagulation, catalytic oxidation, hydrolytic acidification and contact oxidation process was employed for the treatment of high concentration dispersed dye production wastewater. The treatment efficiency of single O_3, UV/TiO_2/O_3 and UV/O_3/H_2O_2 was investigated and compared. The results showed that the UV/TiO_2/O_3 process presented the best performance on dyeing wastewater disposal, the biodegrad-ability of wastewater improved obviously with BOD_5/COD value increased from 0.05-0.07 to 0. 42-0. 46, large a-mount of chroma and COD were also removed during the process. The optimum treatment efficiency of pilot scale sys-tem was found under the conditions of the HRT of coagulation treatment unit was 1.5 h, the HRT of catalytic oxida-tion unit was 3.0 h,the HRT of hydrolytic acidification unit was 10.0 h and the HRT of biological contact oxidation unit was 10.0 h, then COD and chroma removal efficiency could reach 95.0% and 99.5% respectively.

  13. Radiation biophysicl study of biological molecules. Progress report, February 1, 1975--June 30, 1976. [Fast electrons, gamma and uv radiation, Escherichia coli, T1 and lambda bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Fluke, D.J.

    1976-01-01

    Progress is reported on the following research projects: direct action target investigation of molecular weights of enzymes exposed to fast electrons; direct action gamma radiation dosimetry with T/sub 1/ bacteriophage; uv radiation sensitivity of T/sub 1/ bacteriophage on various host strains of E. coli; temperature dependence of uv radiation direct action on dry T/sub 1/ bacteriophage; investigation of light and temperature effects during incubation of T/sub 1/ bacteriophage exposed to fast electrons; test of superoxide anion as a radiation intermediate in cellular radiobiology; uv action spectra related to error-prone repair; uv-reactivation experiments with T/sub 1/ and lambda bacteriophages; and split-dose uv mutagenesis in E. coli. (HLW)

  14. Degradation of antipyrine by UV, UV/H{sub 2}O{sub 2} and UV/PS

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Chaoqun [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092 (China); Gao, Naiyun, E-mail: gaonaiyun@126.com [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092 (China); Deng, Yang [Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043 (United States); Zhang, Yongji; Sui, Minghao; Deng, Jing; Zhou, Shiqing [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092 (China)

    2013-09-15

    Highlights: • The antipyrine decomposition exhibited a pseudo-first-order kinetics pattern well. • The k{sub obs} with irradiance or oxidant dosage presented a linear relationship well. • The k{sub obs} exhibit an exponential trend as a function of [AP]{sub 0} for three systems. • UV/H{sub 2}O{sub 2} behaved best at pH 2.5–10, while UV/PS behaved best at pH 10.0–11.5. • Cost for chemicals was firstly taken into account in calculation of the EE/O values. -- Abstract: Degradation of antipyrine (AP) in water by three UV-based photolysis processes (i.e., direct UV, UV/H{sub 2}O{sub 2}, UV/persulfate (UV/PS)) was studied. For all the oxidation processes, the AP decomposition exhibited a pseudo-first-order kinetics pattern. Generally, UV/H{sub 2}O{sub 2} and UV/PS significantly improved the degradation rate relevant to UV treatment alone. The pseudo-first-order degradation rate constants (k{sub obs}) were, to different degrees, affected by initial AP concentration, oxidant dose, pH, UV irradiation intensity, and co-existing chemicals such as humic acid, chloride, bicarbonate, carbonate and nitrate. The three oxidation processes followed the order in terms of treatment costs: UV/PS > UV > UV/H{sub 2}O{sub 2} if the energy and chemical costs are considered. Finally, the AP degradation pathways in the UV/H{sub 2}O{sub 2} and UV/PS processes are proposed. Results demonstrated that UV/H{sub 2}O{sub 2} and UV/PS are potential alternatives to control water pollution caused by emerging contaminants such as AP.

  15. Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS in Central Europe

    Directory of Open Access Journals (Sweden)

    J. A. Huffman

    2010-04-01

    Full Text Available Primary Biological Aerosol Particles (PBAPs, including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS to measure Fluorescent Biological Aerosol Particles (FBAPs, which provide an estimate of viable bioaerosol particles and can be regarded as an approximate lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (<1 μm, but not for coarse particles (1–20 μm.

    Averaged over the four-month measurement period (August–December 2006, the mean number concentration of coarse FBAPs was ~3×10−2 cm−3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1μg m−3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10−2 cm−3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle (24-h with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be single bacterial cells, larger fungal spores, and pollen grains, respectively.

    The observed number

  16. Fluorescent biological aerosol particle concentrations and size distributions measured with an ultraviolet aerodynamic particle sizer (UV-APS in Central Europe

    Directory of Open Access Journals (Sweden)

    J. A. Huffman

    2009-08-01

    Full Text Available Primary biological aerosol particles (PBAPs, including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany, we used an ultraviolet aerodynamic particle sizer (UV-APS to measure fluorescent biological aerosol particles (FBAPs, which can be regarded as viable bioaerosol particles representing a lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (<1 μm, but not for coarse particles (1–20 μm.

    Averaged over the four-month measurement period (August–December 2006, the mean number concentration of coarse FBAPs was ~3×10−2 cm−3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1 μg m−3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10−2 cm−3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be explained by single bacterial cells, larger fungal spores, and pollen grains, respectively.

    The observed number concentrations and

  17. Crystal structure of a membrane-bound metalloenzyme that catalyses the biological oxidation of methane

    Energy Technology Data Exchange (ETDEWEB)

    Lieberman, R.L.; Rosenzweig, A.C. (NWU)

    2010-03-08

    Particulate methane monooxygenase (pMMO) is an integral membrane metalloenzyme that catalyses the conversion of methane to methanol. Knowledge of how pMMO performs this extremely challenging chemistry may have an impact on the use of methane as an alternative energy source by facilitating the development of new synthetic catalysts. We have determined the structure of pMMO from the methanotroph Methylococcus capsulatus (Bath) to a resolution of 2.8 {angstrom}. The enzyme is a trimer with an {alpha}{sub 3}{beta}{sub 3}{gamma}{sub 3} polypeptide arrangement. Two metal centres, modelled as mononuclear copper and dinuclear copper, are located in soluble regions of each pmoB subunit, which resembles cytochrome c oxidase subunit II. A third metal centre, occupied by zinc in the crystal, is located within the membrane. The structure provides new insight into the molecular details of biological methane oxidation.

  18. Designing deoxidation inhibiting encapsulation of metal oxide nanostructures for fluidic and biological applications

    Science.gov (United States)

    Ghosh, Moumita; Ghosh, Siddharth; Seibt, Michael; Schaap, Iwan A. T.; Schmidt, Christoph F.; Mohan Rao, G.

    2016-12-01

    Due to their photoluminescence, metal oxide nanostructures such as ZnO nanostructures are promising candidates in biomedical imaging, drug delivery and bio-sensing. To apply them as label for bio-imaging, it is important to study their structural stability in a bio-fluidic environment. We have explored the effect of water, the main constituent of biological solutions, on ZnO nanostructures with scanning electron microscopy (SEM) and photoluminescence (PL) studies which show ZnO nanorod degeneration in water. In addition, we propose and investigate a robust and inexpensive method to encapsulate these nanostructures (without structural degradation) using bio-compatible non-ionic surfactant in non-aqueous medium, which was not reported earlier. This new finding is an immediate interest to the broad audience of researchers working in biophysics, sensing and actuation, drug delivery, food and cosmetics technology, etc.

  19. Photocatalytic oxidation of 5-fluorouracil and cyclophosphamide via UV/TiO2 in an aqueous environment.

    Science.gov (United States)

    Lin, Hank Hui-Hsiang; Lin, Angela Yu-Chen

    2014-01-01

    Cytostatic drugs are a class of pharmaceuticals that are increasingly used in cancer therapies; 5-fluorouracil is one of the most commonly used cytostatic (antineoplastic) drugs in the world. This study applied photocatalytic oxidation to remove 5-fluorouracil. Degussa P25 showed a higher photocatalytic degradation efficiency for 5-fluorouracil removal than Aldrich TiO2 and ZnO. Under optimal conditions (20 mg L(-1) TiO2 at pH 5.8), 200 μg L(-1) 5-fluorouracil can be removed within 2 h (k = 0.0375 min(-1)). 5-fluorouracil was found to be decomposed by near-surface OH free radicals produced from valence holes (hvb(+)). At a relatively high concentration, 5-fluorouracil (27.6 mg L(-1)) is >99.9% removed within 4 h by 300 mg L(-1) Degussa P25, while 24 h is required to reach complete mineralization with 96.7% fluoride recovery. Cyclophosphamide is another widely used cancer drug that follows a similar decomposition pathway. Cyclophosphamide (27.6 mg L(-1)) was also >99.9% eliminated within 4 h, but dechlorination and mineralization reached only 79.9% and 55.1%, respectively, after 16 h of irradiation. Together with the results for Microtox(®), it is suggested that the oxidation products of cyclophosphamide are even more recalcitrant and toxic. For engineering practices, despite the fact that photocatalytic oxidation can rapidly remove target antineoplastic, it is also important to further evaluate the treatment efficiency of the photoproducts.

  20. Microparticulated and nanoparticulated zirconium oxide added to calcium silicate cement: Evaluation of physicochemical and biological properties.

    Science.gov (United States)

    Silva, Guilherme F; Bosso, Roberta; Ferino, Rafael V; Tanomaru-Filho, Mário; Bernardi, Maria I B; Guerreiro-Tanomaru, Juliane M; Cerri, Paulo S

    2014-12-01

    The physicochemical and biological properties of calcium silicate-based cement (CS) associated to microparticulated (micro) or nanoparticulated (nano) zirconium oxide (ZrO2 ) were compared with CS and bismuth oxide (BO) with CS. The pH, release of calcium ions, radiopacity, setting time, and compression strength of the materials were evaluated. The tissue reaction promoted by these materials in the subcutaneous was also investigated by morphological, immunohistochemical, and quantitative analyses. For this purpose, polyethylene tubes filled with materials were implanted into rat subcutaneous. After 7, 15, 30, and 60 days, the tubes surrounded by capsules were fixed and embedded in paraffin. In the H&E-stained sections, the number of inflammatory cells (ICs) in the capsule was obtained. Moreover, detection of interleukin-6 (IL-6) by immunohistochemistry and number of IL-6 immunolabeled cells were carried out. von Kossa method was also performed. The differences among the groups were subjected to Tukey test (p ≤ 0.05). The solutions containing the materials presented an alkaline pH and released calcium ions. The addition of radiopacifiers increased setting time and radiopacity of CS. A higher compressive strength in the CS + ZrO2 (micro and nano) was found compared with CS + BO. The number of IC and IL-6 positive cells in the materials with ZrO2 was significantly reduced in comparison with CS + BO. von Kossa-positive structures were observed adjacent to implanted materials. The ZrO2 associated to the CS provides satisfactory physicochemical properties and better biological response than BO. Thus, ZrO2 may be a good alternative for use as radiopacifying agent in substitution to BO.

  1. UV-Vis spectrophotometric studies of self-oxidation/dissociation of quaternary ammonium permanganates (QAP) - impact of solvent polarity

    Science.gov (United States)

    Bank, Suraj Prakash; Guru, Partha Sarathi; Dash, Sukalyan

    2015-05-01

    Self-oxidation/dissociation of some quaternary ammonium permanganates (QAPs), such as cetyltrimethylammonium permanganate (CTAP) and tetrabutylammonium permanganate (TBAP), have been studied spectrophotometrically in six different organic solvent media of different polarities wherein the compounds show good solubility and stability. The optical densities of the substrates at zero time (ODo) and first-order rate constants of dissociation (k1) have been determined from their successive scanning for 40 min. At comparable experimental conditions, absorption capabilities of the substrates are compared from the ODo values in various organic media; the stability of the solutions is compared from the successive scan spectra in those media. The ODo values and the k1 values have been plotted against some solvent parameters to understand their effects on the absorbance and reactivity of the QAPs. These data are also subjected to multiple regression analysis to explain the influence of various solvent parameters on the ion-pairing properties of the substrates, thus elucidating their effects on the process of self-oxidation/dissociation of the substrates.

  2. Synthesis, characterization, and in vitro biological evaluation of highly stable diversely functionalized superparamagnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Dipsikha; Sahu, Sumanta K. [Indian Institute of Technology Kharagpur, Department of Chemistry (India); Banerjee, Indranil [Indian Institute of Technology Kharagpur, Department of Biotechnology (India); Das, Manasmita [Indian Institute of Technology Kharagpur, Department of Chemistry (India); Mishra, Debashish; Maiti, Tapas K. [Indian Institute of Technology Kharagpur, Department of Biotechnology (India); Pramanik, Panchanan, E-mail: dipsikha.chem@gmail.com [Indian Institute of Technology Kharagpur, Department of Chemistry (India)

    2011-09-15

    In this article, we report the design and synthesis of a series of well-dispersed superparamagnetic iron oxide nanoparticles (SPIONs) using chitosan as a surface modifying agent to develop a potential T{sub 2} contrast probe for magnetic resonance imaging (MRI). The amine, carboxyl, hydroxyl, and thiol functionalities were introduced on chitosan-coated magnetic probe via simple reactions with small reactive organic molecules to afford a series of biofunctionalized nanoparticles. Physico-chemical characterizations of these functionalized nanoparticles were performed by TEM, XRD, DLS, FTIR, and VSM. The colloidal stability of these functionalized iron oxide nanoparticles was investigated in presence of phosphate buffer saline, high salt concentrations and different cell media for 1 week. MRI analysis of human cervical carcinoma (HeLa) cell lines treated with nanoparticles elucidated that the amine-functionalized nanoparticles exhibited higher amount of signal darkening and lower T{sub 2} relaxation in comparison to the others. The cellular internalization efficacy of these functionalized SPIONs was also investigated with HeLa cancer cell line by magnetically activated cell sorting (MACS) and fluorescence microscopy and results established selectively higher internalization efficacy of amine-functionalized nanoparticles to cancer cells. These positive attributes demonstrated that these nanoconjugates can be used as a promising platform for further in vitro and in vivo biological evaluations.

  3. Structural, spectroscopic and biological investigation of copper oxides nanoparticles with various capping agents

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, A., E-mail: ana.maria.nowak@gmail.com [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland); Szade, J.; Talik, E.; Ratuszna, A. [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland); Ostafin, M. [Agricultural University of Cracow, Department of Microbiology, Krakow (Poland); Peszke, J. [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland)

    2014-06-01

    Powder composed of copper oxides nanoparticles with various capping agents has been synthesized and characterized with the use of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Polyvinyl alcohol (PVA), glycol propylene, glycerin and glycerin plus ammonia were used as capping agents. The scanning electron microscopy (SEM) studies showed that nanoparticles form agglomerates with the size from 80 to 120 nm while particles size determined from the XRD experiment was in the range from 7 to 21 nm. XPS and XRD experiments revealed that depending on capping and reducing agents used in the synthesis nanoparticles are composed of Cu{sub 2}O, CuO or a mixture of them. The biological activity test performed for a selected sample where the capping agent was glycerin plus ammonia has shown promising killing/inhibiting behavior, very effective especially for Gram negatives bacteria. - Highlights: • We obtained copper oxide nanoparticles in a powder form. • Several capping agents were tested. • Structural and chemical tests showed that the main component were Cu{sub 2}O and CuO. • The size of nanoparticles was in the range 7–21 nm. • Nanoparticles with glycerin and ammonia capping agent showed good antibacterial properties.

  4. Superior drainage treated by combinational technique of biologic contact oxidation and constructed wetland

    Institute of Scientific and Technical Information of China (English)

    胡学斌; 徐志恒; 柴宏祥; 龙腾锐

    2009-01-01

    The superior drainage was pre-treated by biologic contact oxidation on BOD5 load of 0.72 kg/(m3·d),and then post-treated by constructed wetland. The results about the effect on the constructed wetland post-treatment show that the total nitrogen (TN) is the restrictive index of the combinational technique treatment effect. To meet the reclaimed water quality standard and reuse for waterscape,the peak hydraulic load of constructed wetland is 0.50 m/d in summer (30-36 ℃) and 0.33 m/d in winter (8-12℃),and the load ratio of the peak hydraulic under the two temperature conditions is 3-2. The results are combined of reclaimed water quantity requirements in different seasons of green building. Reasonable scale of the reclaimed water treatment systems can be determined. The treatment efficacy can be well predicted,and both the design and operations can be effectively guided,by which the reclaimed water treatment systems regard superior drainage as the source and are purified by combinational technique of contact oxidation and artificial wetland.

  5. Treatment of textile effluent by chemical (Fenton's Reagent) and biological (sequencing batch reactor) oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Carmen S.D. [LSRE - Laboratory of Separation and Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal); Madeira, Luis M. [LEPAE - Laboratory for Process, Environmental and Energy Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal); Boaventura, Rui A.R., E-mail: bventura@fe.up.pt [LSRE - Laboratory of Separation and Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal)

    2009-12-30

    The removal of organic compounds and colour from a synthetic effluent simulating a cotton dyeing wastewater was evaluated by using a combined process of Fenton's Reagent oxidation and biological degradation in a sequencing batch reactor (SBR). The experimental design methodology was first applied to the chemical oxidation process in order to determine the values of temperature, ferrous ion concentration and hydrogen peroxide concentration that maximize dissolved organic carbon (DOC) and colour removals and increase the effluent's biodegradability. Additional studies on the biological oxidation (SBR) of the raw and previously submitted to Fenton's oxidation effluent had been performed during 15 cycles (i.e., up to steady-state conditions), each one with the duration of 11.5 h; Fenton's oxidation was performed either in conditions that maximize the colour removal or the increase in the biodegradability. The obtained results allowed concluding that the combination of the two treatment processes provides much better removals of DOC, BOD{sub 5} and colour than the biological or chemical treatment alone. Moreover, the removal of organic matter in the integrated process is particularly effective when Fenton's pre-oxidation is carried out under conditions that promote the maximum increase in wastewater biodegradability.

  6. Mentha suaveolens Ehrh. (Lamiaceae Essential Oil and Its Main Constituent Piperitenone Oxide: Biological Activities and Chemistry

    Directory of Open Access Journals (Sweden)

    Mijat Božović

    2015-05-01

    Full Text Available Since herbal medicines play an important role in the treatment of a wide range of diseases, there is a growing need for their quality control and standardization. Mentha suaveolens Ehrh. (MS is an aromatic herb with fruit and a spearmint flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including cytotoxic, antimicrobial, antioxidant, anti-inflammatory, hypotensive and insecticidal properties, among others. This study aims to review the scientific findings and research reported to date on MS that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, piperitenone oxide (PO, the major chemical constituent of the carvone pathway MS essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested.

  7. Biokinetics of zinc oxide nanoparticles: toxicokinetics, biological fates, and protein interaction

    Directory of Open Access Journals (Sweden)

    Choi SJ

    2014-12-01

    Full Text Available Soo-Jin Choi,1 Jin-Ho Choy2 1Department of Food Science and Technology, Seoul Women's University, 2Center for Intelligent Nano Bio Materials (CINBM, Department of Bioinspired Science and Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, South Korea Abstract: Biokinetic studies of zinc oxide (ZnO nanoparticles involve systematic and quantitative analyses of absorption, distribution, metabolism, and excretion in plasma and tissues of whole animals after exposure. A full understanding of the biokinetics provides basic information about nanoparticle entry into systemic circulation, target organs of accumulation and toxicity, and elimination time, which is important for predicting the long-term toxic potential of nanoparticles. Biokinetic behaviors can be dependent on physicochemical properties, dissolution property in biological fluids, and nanoparticle–protein interaction. Moreover, the determination of biological fates of ZnO nanoparticles in the systemic circulation and tissues is critical in interpreting biokinetic behaviors and predicting toxicity potential as well as mechanism. This review focuses on physicochemical factors affecting the biokinetics of ZnO nanoparticles, in concert with understanding bioavailable fates and their interaction with proteins. Keywords: ZnO nanoparticles, biokinetics, distribution, excretion, fate, interaction

  8. A coupled advanced oxidation-biological process for recycling industrial wastewater containing persistent organic contaminants (CADOX)

    Energy Technology Data Exchange (ETDEWEB)

    Malato, S.; Blanco, J.; Maldonado, M.I.; Alarcon, D.C.; Fernandez, P.; Oller, I.; Gernjak, W. [Platforma Solar de Almeria, CIEMAT (Spain)

    2004-07-01

    This article concentrates on coupled processes to treat seven highly water-soluble pesticides and three non-biodegradable chlorinated solvents. These are considered priority substances by the European Union and are thus the focus of some attention. The coupled processes include three oxidation processes: photocatalysis by titanium dioxide, photo-Fenton, and ozone; as well as biological degradation. The article reports on work in progress. The full project will include building two small prototypes embodying these technologies, the construction of a demonstration treatment plant based on the results obtained from the prototypes, conceptual design of a full size plant. New solar collectors were built to facilitate the photocatalysis and photo-Fenton. To date it has been determined that the photo-catalysis and photo-Fenton are suitable if the concentrations of the above contaminants is high enough. Ozone can enhance the treatment in the case of the pesticides, but not in the case of the non-biodegradable chlorinated solvents. Biotreatment is also not suitable for the solvents. The best biological system has been determined and the optimal recovery of catalyst has also been found. 5 refs., 2 tabs., 4 figs.

  9. Mentha suaveolens Ehrh. (Lamiaceae) Essential Oil and Its Main Constituent Piperitenone Oxide: Biological Activities and Chemistry.

    Science.gov (United States)

    Božović, Mijat; Pirolli, Adele; Ragno, Rino

    2015-05-13

    Since herbal medicines play an important role in the treatment of a wide range of diseases, there is a growing need for their quality control and standardization. Mentha suaveolens Ehrh. (MS) is an aromatic herb with fruit and a spearmint flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including cytotoxic, antimicrobial, antioxidant, anti-inflammatory, hypotensive and insecticidal properties, among others. This study aims to review the scientific findings and research reported to date on MS that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, piperitenone oxide (PO), the major chemical constituent of the carvone pathway MS essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested.

  10. [Total synthesis of biologically active alkaloids using bio-inspired indole oxidation].

    Science.gov (United States)

    Ishikawa, Hayato

    2015-01-01

    Many tryptophan-based dimeric diketopiperazine (DKP) alkaloids including WIN 64821 and ditryptophenaline, which exhibit fascinating biological activities, have been isolated from fungi. These alkaloids possess a unique architecture; therefore several total syntheses of these compounds have been accomplished via bio-inspired reactions. Despite these elegant strategies, we were convinced that a more direct bio-inspired solution for the preparation of tryptophan-based DKP alkaloids was possible because in a true biosynthesis, direct dimerization of tryptophan occurs in aqueous media without incorporation of a protecting group on the substrates. Thus we developed direct bio-inspired dimerization reactions in aqueous, acidic media, along with a novel biomimetic pathway, to provide C2-symmetric and non-symmetric dimeric compounds from commercially available amine-free tryptophan derivatives using Mn(OAc)3, VOF3, and V2O5 as one-electron oxidants. In addition, concise two-pot or three-step syntheses of the naturally occurring dimeric DKP alkaloids (+)-WIN 64821, (-)-ditryptophenaline, and (+)-naseseazine B were accomplished with total yields of 20%, 13%, and 20%, respectively. The present synthesis has several noteworthy features: 1) the tryptophan-based C2-symmetric and non-symmetric dimeric key intermediates can be prepared on a multigram scale in one step; 2) the developed oxidation reaction was carried out in aqueous, acidic solution without deactivation of the metal oxidants; 3) protection of the primary amine can be avoided by salt formation in aqueous acid; 4) for the total two-pot operation, the reaction media are environmentally friendly water and ethanol; 5) satisfactory total yields are obtained compared with previously reported syntheses.

  11. Structure and UV photoluminescence of nanocrystalline ZnO films prepared by thermal oxidation of ZnS films

    Energy Technology Data Exchange (ETDEWEB)

    Gao, X.D. [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics of Chinese Academy of Sciences, Dingxi Road, No. 1295, Shanghai 200050 (China)]. E-mail: xdgao@mail.sic.ac.cn; Li, X.M. [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics of Chinese Academy of Sciences, Dingxi Road, No. 1295, Shanghai 200050 (China); Yu, W.D. [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics of Chinese Academy of Sciences, Dingxi Road, No. 1295, Shanghai 200050 (China)

    2004-11-15

    Nanocrystalline ZnO films were fabricated using thermal oxidation of ZnS films deposited by successive ionic layer adsorption and reaction (SILAR) method. The crystalline structure and morphology of obtained films were characterized by X-ray diffraction (XRD) and scanning electronic microscope (SEM). Optical properties including the optical absorption coefficient and photoluminescence were investigated. Results show that obtained ZnO film exhibits excellent crystalline structure with the preferential orientation of <1 0 0>, dense morphology with particle size of 20-50 nm, high transmittance over 80% in vis-near-infrared band, and sharp absorption edge near 380 nm. At the excitation of 340 nm photon, the film shows a strong and sharp ultraviolet emission at 390 nm and several weak emissions in blue band, illustrating its high optical quality. The oxygen content in the annealing atmosphere has significant effects on the structure and optical properties of ZnO film.

  12. The mechanisms of UV mutagenesis.

    Science.gov (United States)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

    Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: "error-free" bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases--the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation.

  13. Graphene oxide modified ZnO nanorods hybrid with high reusable photocatalytic activity under UV-LED irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Lu, Luhua, E-mail: lhlu@whut.edu.cn [State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Liang, Changhao; Dai, Jianming [Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China); Zhu, Guangping; Liu, Zhongliang; Liu, Qinzhuang; Zhang, Yongxing [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China)

    2014-02-14

    In this work, graphene oxide/zinc oxide (GO/ZnO) hybrid was prepared through a facile hydrothermal process. Transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectra and N{sub 2} adsorption and desorption isotherms were used to investigate the morphology, crystal structure, optical properties and specific surface area of GO/ZnO hybrid. It was shown that the well-dispersed ZnO nanorods were deposited on GO homogeneously. Photocatalytic properties of GO/ZnO nanorods hybrid were evaluated under 375 nm light-emitting diode light irradiation for photodegradation of methylene blue (MB). The synergic effect between GO and ZnO was found to lead to an improved photo-generated carrier separation. An optimal GO content has been determined to be 3 wt%, and corresponding the apparent pseudo-first-order rate constant k{sub app} is 0.0248 min{sup −1}, 4.3 times and 2.5 times more than that of pure ZnO nanorods and commercial P25 photocatalyst, respectively. Moreover, the cyclic photocatalytic test indicated that GO/ZnO hybrid can be reused for degradation of MB, suggesting the possible application of GO/ZnO hybrid as excellent candidate for water treatment. - Highlights: • GO/ZnO hybrid was successfully synthesized by hydrothermal process. • GO/ZnO hybrid showed high photocatalytic activity with irradiation of LED light. • Effective photo-electrons separation and fast transportation. • Excellent recycled performance was achieved by GO/ZnO hybrid.

  14. Recent progress on application of UV excilamps for degradation of organic pollutants and microbial inactivation.

    Science.gov (United States)

    Matafonova, Galina; Batoev, Valeriy

    2012-10-01

    Excilamps as modern mercury-free sources of narrow-band UV radiation represent an attractive alternative in environmental applications. This review focuses on recent studies on the water and surface decontamination with excilamps by means of direct photolysis and advanced oxidation processes. To date, direct photolysis and advanced oxidation processes (AOPs) such as UV/H(2)O(2), UV/Fenton and UV/O(3) have been applied for degradation of organic compounds (mainly, phenols, dyes and herbicides) in model aqueous solutions. Special emphasis is placed on studies combining UV irradiation (as a pre-treatment or post-treatment step) with biological treatment. In this review, the efficiencies of direct UV, UV/H(2)O(2) and UV/TiO(2) processes for inactivation of a variety of pathogenic microorganisms in water and on surfaces are discussed. The analysis of the literature shows that more works need to be done on scaling up the processes, degradation/mineralization of target pollutant(s) in real effluents and evaluation of energy requirements.

  15. Developing mononuclear copper-active-oxygen complexes relevant to reactive intermediates of biological oxidation reactions.

    Science.gov (United States)

    Itoh, Shinobu

    2015-07-21

    Active-oxygen species generated on a copper complex play vital roles in several biological and chemical oxidation reactions. Recent attention has been focused on the reactive intermediates generated at the mononuclear copper active sites of copper monooxygenases such as dopamine β-monooxygenase (DβM), tyramine β-monooxygenase (TβM), peptidylglycine-α-hydroxylating monooxygenase (PHM), and polysaccharide monooxygenases (PMO). In a simple model system, reaction of O2 and a reduced copper(I) complex affords a mononuclear copper(II)-superoxide complex or a copper(III)-peroxide complex, and subsequent H(•) or e(-)/H(+) transfer, which gives a copper(II)-hydroperoxide complex. A more reactive species such as a copper(II)-oxyl radical type species could be generated via O-O bond cleavage of the peroxide complex. However, little had been explored about the chemical properties and reactivity of the mononuclear copper-active-oxygen complexes due to the lack of appropriate model compounds. Thus, a great deal of effort has recently been made to develop efficient ligands that can stabilize such reactive active-oxygen complexes in synthetic modeling studies. In this Account, I describe our recent achievements of the development of a mononuclear copper(II)-(end-on)superoxide complex using a simple tridentate ligand consisting of an eight-membered cyclic diamine with a pyridylethyl donor group. The superoxide complex exhibits a similar structure (four-coordinate tetrahedral geometry) and reactivity (aliphatic hydroxylation) to those of a proposed reactive intermediate of copper monooxygenases. Systematic studies based on the crystal structures of copper(I) and copper(II) complexes of the related tridentate supporting ligands have indicated that the rigid eight-membered cyclic diamine framework is crucial for controlling the geometry and the redox potential, which are prerequisites for the generation of such a unique mononuclear copper(II)-(end-on)superoxide complex

  16. Biological interactions in vitro of zinc oxide nanoparticles of different characteristics

    Science.gov (United States)

    Aula, Sangeetha; Lakkireddy, Samyuktha; AVN, Swamy; Kapley, Atya; Jamil, Kaiser; Rao Tata, Narasinga; Hembram, Kaliyan

    2014-09-01

    Zinc oxide nanoparticles (ZnO NPs) have recently received growing attention for various biomedical applications, including use as therapeutic or carrier for drug delivery and/or imaging. For the above applications, the NPs necessitate administration into the body leading to their systemic exposure. To better anticipate the safety, make risk assessment, and be able to interpret the future preclinical and clinical safety data, it is important to systematically understand the biological interaction of the NPs, the consequences of such interaction, and the mechanisms associated with the toxicity induction, with the important components with which the NPs are expected to be in contact after systemic exposure. In this context, we report here a detailed study on the biological interactions in vitro of the ZnO NPs with healthy human primary lymphocytes as these are the important immune components and the first systemic immune contact, and with the whole human blood. Additionally, the influence, if any, of the NPs shape (spheres and rods) on the biological interaction has been evaluated. The ZnO NPs caused toxicity (30% at 12.5 μg ml-1 spheres and 10.5 μg ml-1 rods; 50% at 22 μg ml-1 spheres and 19.5 μg ml-1 rods) to the lymphocytes at molecular and genetic level in a dose-dependent and shape-dependent manner, while the interaction consequences with the blood and blood components such as RBC, platelets was only dose-dependent and not shape-dependent. This is evident from the decreased RBC count due to increased %Hemolysis (5.3% in both the spheres- and rods-treated blood) and decreased platelet count due to increased %platelet aggregation (28% in spheres-treated and 33% in rods-treated platelet-rich plasma). Such in-depth understanding of the biological interaction of the NPs, the consequences, and the associated mechanisms in vitro could be expected to allow anticipating the NP safety for risk assessment and for interpretation of the preclinical and clinical safety

  17. Biochemical ripening of dredged sediments. Part 1. Kinetics of biological organic matter mineralization and chemical sulfur oxidation

    NARCIS (Netherlands)

    Vermeulen, J.; Gool, M.P.M. van; Dorleijn, A.S.; Joziasse, J.; Bruning, H.; Rulkens, W.H.; Grotenhuis, J.T.C.

    2007-01-01

    After dredged sediments have settled in a temporary upland disposal site, ripening starts, which turns waterlogged sediment into aerated soil. Aerobic biological mineralization of organic matter (OM) and chemical oxidation of reduced sulfur compounds are the major biochemical ripening processes. Qua

  18. Modeling Nitrous Oxide Production during Biological Nitrogen Removal via Nitrification and Denitrification: Extensions to the General ASM Models

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Ruscalleda, Maël; Pellicer i Nàcher, Carles

    2011-01-01

    Nitrous oxide (N2O) can be formed during biological nitrogen (N) removal processes. In this work, a mathematical model is developed that describes N2O production and consumption during activated sludge nitrification and denitrification. The well-known ASM process models are extended to capture N2O...... dynamics during both nitrification and denitrification in biological N removal. Six additional processes and three additional reactants, all involved in known biochemical reactions, have been added. The validity and applicability of the model is demonstrated by comparing simulations with experimental data...... on N2O production from four different mixed culture nitrification and denitrification reactor study reports. Modeling results confirm that hydroxylamine oxidation by ammonium oxidizers (AOB) occurs 10 times slower when NO2– participates as final electron acceptor compared to the oxic pathway. Among...

  19. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  20. Photocatalytic oxidation of selected gas-phase VOCs using UV light, TiO2, and TiO2/Pd.

    Science.gov (United States)

    Fujimoto, Tânia M; Ponczek, Milena; Rochetto, Ursula L; Landers, Richard; Tomaz, Edson

    2016-03-30

    Heterogeneous photocatalytic oxidation systems using titanium dioxide (TiO2) have been extensively studied for the removal of several volatile organic compounds (VOCs). The addition of noble metals such as palladium on TiO2 may improve photocatalytic activity by increasing charge separation efficiency. In this work, palladium was impregnated on TiO2 and the efficiency of the new catalyst was tested and compared with that of pure TiO2. Pd was impregnated on TiO2 by the reduction method, using NaBH4, and was characterized by XRD, XPS, UV-Vis, and H2 chemisorption. The photocatalytic tests were performed in an annular coated-wall reactor using octane, isooctane, n-hexane, and cyclohexane at inlet concentrations varying from 100 to 120 ppmv. Compared with pure TiO2 film, the photocatalytic activity of TiO2 impregnated with 1 wt% of palladium was improved. All the aforementioned analytical techniques confirmed the presence of Pd incorporated into the structure of TiO2, and the conversion rates were studied in a broad range of residence times, yielding up to 90 % or higher rates in 40 s of residence time, thus underscoring the relevant contribution of the technology.

  1. Quantum chemical calculation (electronic and topologic) and experimental (FT-IR, FT-Raman and UV) analysis of isonicotinic acid N-oxide

    Science.gov (United States)

    Karaca, Caglar; Atac, Ahmet; Karabacak, Mehmet

    2015-04-01

    In this work, the molecular conformation, vibrational and electronic analysis of isonicotinic acid N-oxide (iso-NANO) were presented in the ground state using experimental techniques (FT-IR, FT-Raman and UV) and density functional theory (DFT) employing B3LYP exchange correlation with the 6-311++G(d,p) basis set. The geometry optimization and energies associated possible two conformers (Rot-I and Rot-II) were computed. The vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The obtained structures were analyzed with the Atoms in Molecules (AIMs) methodology. The computational results diagnose the most stable conformer of iso-NANO as the Rot-I form. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (OPDOS) diagrams analysis for the most stable conformer (Rot-I) were calculated using the same method. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated. As a result, the optimized geometry and calculated spectroscopic data show a good agreement with the experimental results.

  2. Colour and organic removal of biologically treated coffee curing wastewater by electrochemical oxidation method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The treatment of biologically treated wastewater of coffee-curing industry by the electrochemical oxidation using steel anode were investigated. Bench-scale experiments were conducted for activated sludge process on raw wastewater and the treated effluents were further treated by electrochemical oxidation method for its color and organic content removal. The efficiency of the process was determined in terms of removal percentage of COD, BOD and color during the course of reaction. Several operating parameters like time, pH and current density were examined to ascertain their effects on the treatment efficiency. Steel anode was found to be effective for the COD and color removal with anode efficiency of 0.118 kgCOD-1A-1m-2 and energy consumption 20.61 kWh.kg-1 of COD at pH 9. The decrease in pH from 9 to 3 found to increase the anode efficiency from 0.118 kgCOD-1A-1m-2 to 0.144 kWh.kg-1 of COD while decrease the energy consumption from 20.61 kWh.kg-1 of COD to12 .86 kWh.kg-1 of COD. The pH of 5 was considered an ideal from the present treatment process as it avoids the addition of chemicals for neutralization of treated effluents and also economical with respect to energy consumption. An empirical relation developed for relationship between applied current density and COD removal efficiency showed strong predictive capability with coefficient of determination of 96.5%.

  3. Study on the coordinative oxidation effect of ferrate and UV-vis/TiO2%高铁酸钾与UV-vis/TiO2协同氧化效应的研究

    Institute of Scientific and Technical Information of China (English)

    郗丽娟; 张瑛洁; 杨文慧; 陈雷; 王禄鹏; 赵徐军; 马军

    2007-01-01

    为研究高铁酸钾与紫外-可见光/二氧化钛(UV-vis/TiO2)光催化的协同氧化效应,以氨氮为目标物,研究了高铁酸钾、UV-vis/TiO2光催化以及高铁酸钾与UV-vis/TiO2光催化联用对水中氨氮的去除效果.结果表明,在高铁酸钾与UV-vis/TiO2光催化联用的条件下,在pH=8.0,温度为室温,反应时间为30 min,氨氮质量浓度50 mg/L,高铁酸钾、TiO2投加质量浓度分别为20、200 mg/L时,水中氨氮的去除率为97.5%,比单独的高铁酸钾或UV-vis/TiO2最大去除率分别提高了22.5%和14.7%.实验还表明,低浓度的高铁酸钾与UV-vis/TiO2光催化体系存在协同氧化效应,但高浓度的高铁酸钾对UV-vis/TiO2光催化体系却存在抑制效应.

  4. Superoxide-dependent consumption of nitric oxide in biological media may confound in vitro experiments.

    Science.gov (United States)

    Keynes, Robert G; Griffiths, Charmaine; Garthwaite, John

    2003-01-15

    NO functions ubiquitously as a biological messenger but has also been implicated in various pathologies, a role supported by many reports that exogenous or endogenous NO can kill cells in tissue culture. In the course of experiments aimed at examining the toxicity of exogenous NO towards cultured cells, we found that most of the NO delivered using a NONOate (diazeniumdiolate) donor was removed by reaction with the tissue-culture medium. Two NO-consuming ingredients were identified: Hepes buffer and, under laboratory lighting, the vitamin riboflavin. In each case, the loss of NO was reversed by the addition of superoxide dismutase. The effect of Hepes was observed over a range of NONOate concentrations (producing up to 1 microM NO). Furthermore, from measurements of soluble guanylate cyclase activity, Hepes-dependent NO consumption remained significant at the low nanomolar NO concentrations relevant to physiological NO signalling. The combination of Hepes and riboflavin (in the light) acted synergistically to the extent that, instead of a steady-state concentration of about 1 microM being generated, NO was undetectable (<10 nM). Again, the consumption could be inhibited by superoxide dismutase. A scheme is proposed whereby a "vicious cycle" of superoxide radical (O(2)(.-)) formation occurs as a result of oxidation of Hepes to its radical species, fuelled by the subsequent reaction of O(2)(.-) with NO to form peroxynitrite (ONOO(-)). The inadvertent production of ONOO(-) and other reactive species in biological media, or the associated loss of NO, may contribute to the adverse effects, or otherwise, of NO in vitro.

  5. Natural Products Mediated Regulation of Oxidative Stress and DNA Damage in Ultraviolet Exposed Skin Cells.

    Science.gov (United States)

    Farooqi, Ammad A; Li, Ruei-Nian; Huang, Hurng-Wern; Ismail, Muhammad; Yuan, Shyng-Shiou F; Wang, Hui-Min D; Liu, Jing-Ru; Tang, Jen-Yang; Chang, Hsueh-Wei

    2015-01-01

    Data obtained through high-throughput technologies have gradually revealed that a unique stratified epithelial architecture of human skin along with the antioxidant-response pathways provided vital defensive mechanisms against UV radiation. However, it is noteworthy that skin is a major target for toxic insult by UV radiations that can alter its structure and function. Substantial fraction of information has been added into the existing pool of knowledge related to natural products mediated biological effects in UV exposed skin cells. Accumulating evidence has started to shed light on the potential of these bioactive ingredients as protective natural products in cosmetics against UV photodamage by exerting biological effects mainly through wide ranging intracellular signalling cascades of oxidative stress and modulation of miRNAs. In this review, we have summarized recently emerging scientific evidences addressing underlying mechanisms of UV induced oxidative stress and deregulation of signalling cascades and how natural products can be used tactfully to protect against UV induced harmful effects.

  6. Electrochemical and biological characterization of coatings formed on Ti-15Mo alloy by plasma electrolytic oxidation.

    Science.gov (United States)

    Kazek-Kęsik, Alicja; Krok-Borkowicz, Małgorzata; Pamuła, Elżbieta; Simka, Wojciech

    2014-10-01

    β-Type titanium alloys are considered the future materials for bone implants. To improve the bioactivity of Ti-15Mo, the surface was modified using the plasma electrolytic oxidation (PEO) process. Tricalcium phosphate (TCP, Ca3PO4), wollastonite (CaSiO3) and silica (SiO2) were selected as additives in the anodizing bath to enhance the bioactivity of the coatings formed during the PEO process. Electrochemical analysis of the samples was performed in Ringer's solution at 37°C. The open-circuit potential (EOCP) as a function of time, corrosion potential (ECORR), corrosion current density (jCORR) and polarization resistance (Rp) of the samples were determined. Surface modification improved the corrosion resistance of Ti-15Mo in Ringer's solution. In vitro studies with MG-63 osteoblast-like cells were performed for 1, 3 and 7 days. After 24h, the cells were well adhered on the entire surfaces, and their number increased with increasing culture time. The coatings formed in basic solution with wollastonite exhibited better biological performance compared with the as-ground sample.

  7. Influence of SiO2 and graphene oxide nanoparticles on efficiency of biological removal process.

    Science.gov (United States)

    Esmaeili-Faraj, Seyyed Hamid; Nasr Esfahany, Mohsen

    2017-01-19

    The effects of the presence of synthesized silica (SS) and exfoliated graphene oxide (EGO) on the removal of sulfide ion with activated sludge (AS) are experimentally investigated. The maximum removal efficiency of sulfide ion for AS without nanoparticles, and the samples with SS and EGO nanoparticles were 81%, 88% and 79%, respectively. Moreover, the maximum elimination capacity (ECmax) for the bioreactor with SS-nanoparticles is 7542 mg/L s, while the ECmax of AS and EGO samples were 7075 and 6625 mg/L s, respectively. Two filamentous microbial strains as Gram-negative and Gram-positive bacteria are discerned that removed sulfide ion in the presence of nanoparticles. The measurement of mixture liquor volatile suspended solid that indicates the biomass growth rate during the test shows that the bioreactor containing SS-nanoparticles has more biomass content than the other samples. Our findings indicate that SS-nanoparticles with 0.1% wt. concentration in the bioreactor have no negative effects on the efficiency of the biological removal of sulfide and the presence of SS-nanoparticles even enhances the performance of the bioreactor. On the other side, a bioreactor with EGO nanosheets, as highly antibacterial nanoparticles, with 0.02% wt. concentration significantly influences the microbial growth and reduces sulfide removal efficiency.

  8. Biological Characteristics of Fluorescent Superparamagnetic Iron Oxide Labeled Human Dental Pulp Stem Cells

    Science.gov (United States)

    Li, Ming-wei; Bai, Yu; Guo, Hui-hui

    2017-01-01

    Tracking transplanted stem cells is necessary to clarify cellular properties and improve transplantation success. In this study, we investigate the effects of fluorescent superparamagnetic iron oxide particles (SPIO) (Molday ION Rhodamine-B™, MIRB) on biological properties of human dental pulp stem cells (hDPSCs) and monitor hDPSCs in vitro and in vivo using magnetic resonance imaging (MRI). Morphological analysis showed that intracellular MIRB particles were distributed in the cytoplasm surrounding the nuclei of hDPSCs. 12.5–100 μg/mL MIRB all resulted in 100% labeling efficiency. MTT showed that 12.5–50 μg/mL MIRB could promote cell proliferation and MIRB over 100 μg/mL exhibited toxic effect on hDPSCs. In vitro MRI showed that 1 × 106 cells labeled with various concentrations of MIRB (12.5–100 μg/mL) could be visualized. In vivo MRI showed that transplanted cells could be clearly visualized up to 60 days after transplantation. These results suggest that 12.5–50 μg/mL MIRB is a safe range for labeling hDPSCs. MIRB labeled hDPSCs cell can be visualized by MRI in vitro and in vivo. These data demonstrate that MIRB is a promising candidate for hDPSCs tracking in hDPSCs based dental pulp regeneration therapy. PMID:28298928

  9. The potential for biologically catalyzed anaerobic methane oxidation on ancient Mars.

    Science.gov (United States)

    Marlow, Jeffrey J; Larowe, Douglas E; Ehlmann, Bethany L; Amend, Jan P; Orphan, Victoria J

    2014-04-01

    This study examines the potential for the biologically mediated anaerobic oxidation of methane (AOM) coupled to sulfate reduction on ancient Mars. Seven distinct fluids representative of putative martian groundwater were used to calculate Gibbs energy values in the presence of dissolved methane under a range of atmospheric CO2 partial pressures. In all scenarios, AOM is exergonic, ranging from -31 to -135 kJ/mol CH4. A reaction transport model was constructed to examine how environmentally relevant parameters such as advection velocity, reactant concentrations, and biomass production rate affect the spatial and temporal dependences of AOM reaction rates. Two geologically supported models for ancient martian AOM are presented: a sulfate-rich groundwater with methane produced from serpentinization by-products, and acid-sulfate fluids with methane from basalt alteration. The simulations presented in this study indicate that AOM could have been a feasible metabolism on ancient Mars, and fossil or isotopic evidence of this metabolic pathway may persist beneath the surface and in surface exposures of eroded ancient terrains.

  10. Quinoxaline 1,4-di-N-Oxides: Biological Activities and Mechanisms of Actions.

    Science.gov (United States)

    Cheng, Guyue; Sa, Wei; Cao, Chen; Guo, Liangliang; Hao, Haihong; Liu, Zhenli; Wang, Xu; Yuan, Zonghui

    2016-01-01

    Quinoxaline 1,4-di-N-oxides (QdNOs) have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and bacterial resistance have been found in QdNO antibacterial growth promoters, conferring urgent need for discovery of new QdNO drugs. However, the modes of actions of QdNOs are not fully understood, hindering the development and innovation of these promising compounds. Here, QdNOs are categorized based on the activities and usages, among which the antimicrobial activities are consist of antibacterial, antimycobacterial and anticandida activities, and the antiprotozoal activities include antitrypanosomal, antimalarial, antitrichomonas, and antiamoebic activities. The structure-activity relationship and the mode of actions of each type of activity of QdNOs are summarized, and the toxicity and the underlying mechanisms are also discussed, providing insight for the future research and development of these fascinating compounds.

  11. Quinoxaline 1, 4-di-N-oxides: Biological activities and mechanisms of actions

    Directory of Open Access Journals (Sweden)

    Guyue eCheng

    2016-03-01

    Full Text Available Quinoxaline 1, 4-di-N-oxides (QdNOs have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and bacterial resistance have been found in QdNO antibacterial growth promoters, conferring urgent need for discovery of new QdNO drugs. However, the modes of actions of QdNOs are not fully understood, hindering the development and innovation of these promising compounds. Here, QdNOs are categorized based on the activities and usages, among which the antimicrobial activities are consist of antibacterial, antimycobacterial and anticandida activities, and the antiprotozoal activities include antitrypanosomal, antimalarial, antitrichomonas and antiamoebic activities. The structure-activity relationship and the mode of actions of each type of activity of QdNOs are summarized, and the toxicity and the underlying mechanisms are also discussed, providing insight for the future research and development of these fascinating compounds.

  12. Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of catalytic ultrasound oxidation and membrane bioreactor.

    Science.gov (United States)

    Jia, Shengyong; Han, Hongjun; Zhuang, Haifeng; Xu, Peng; Hou, Baolin

    2015-01-01

    Laboratorial scale experiments were conducted to investigate a novel system integrating catalytic ultrasound oxidation (CUO) with membrane bioreactor (CUO-MBR) on advanced treatment of biologically pretreated coal gasification wastewater. Results indicated that CUO with catalyst of FeOx/SBAC (sewage sludge based activated carbon (SBAC) which loaded Fe oxides) represented high efficiencies in eliminating TOC as well as improving the biodegradability. The integrated CUO-MBR system with low energy intensity and high frequency was more effective in eliminating COD, BOD5, TOC and reducing transmembrane pressure than either conventional MBR or ultrasound oxidation integrated MBR. The enhanced hydroxyl radical oxidation, facilitation of substrate diffusion and improvement of cell enzyme secretion were the mechanisms for CUO-MBR performance. Therefore, the integrated CUO-MBR was the promising technology for advanced treatment in engineering applications.

  13. UV-Fenton体系氧化降解邻氯苯酚废水反应动力学研究%Kinetic study of o-chlorophenol wastewater treatment by UV-Fenton oxidation

    Institute of Scientific and Technical Information of China (English)

    熊思江; 刘琼玉; 张如月; 王芬

    2007-01-01

    采用UV-Fenton高级氧化技术对邻氯苯酚废水进行了处理研究.从反应速率系数着手探讨了污染物初始浓度、双氧水加入量、亚铁离子浓度及pH值对反应降解速率的影响.用半衰期法对邻氯苯酚的反应级数进行了探讨,确定其在UV-Fenton体系降解过程中的表观反应级数为3/2,并初步建立了邻氯苯酚UV-Fenton降解的动力学模型.

  14. Kinetic Studies on Phenol Wastewater Treatment by UV-Fenton Oxidation%UV-Fenton 体系氧化降解苯酚废水反应动力学研究

    Institute of Scientific and Technical Information of China (English)

    熊思江; 刘琼玉; 张如月

    2007-01-01

    利用UV-Fenton高级氧化技术对苯酚废水进行了处理研究.通过半衰期法对苯酚的反应级数进行了探讨,确定其在UV-Fenton体系降解过程中的表观反应级数为3/2,并初步建立了苯酚UV-Fenton降解的动力学模型,并从反应速率系数着手探讨了污染物初始浓度、双氧水加入量、亚铁离子浓度及pH值对反应降解速率的影响.

  15. Effects of a vanadium post-metallocene catalyst-induced polymer backbone inhomogeneity on UV oxidative degradation of the resulting polyethylene film

    KAUST Repository

    Atiqullah, M.

    2012-07-01

    A Group 5 post-metallocene precatalyst, (ONO)VCl(THF) 2 (ONO = a bis(phenolate)pyridine LX 2 pincer ligand), activated with modified methylaluminoxane (MMAO-3A) produced a linear ethylene homopolymer (nm-HomoPE)and an unusual inhomogeneous copolymer (nm-CopolyPE) with 1-hexene having very low backbone unsaturation. The nm-CopolyPE inhomogeneity was reflected in the distributions of short chain branches, 1-hexene composition, and methylene sequence length. The 1-hexene incorporation into the polyethylene backbone strongly depended on the molecular weight of the growing polymer chain. (ONO)VCl(THF) 2, because of site diversity and easier removal of a tertiary (vs. a secondary) hydrogen, produced a skewed short chain branching (SCB) profile, incorporating 1-hexene more efficiently in the low molecular weight region than in the high molecular weight region. The significant decrease in molecular weight by 1-hexene showed that the (ONO)VCl(THF) 2 catalytic sites were also highly responsive to chain-transfer directly to 1-hexene itself, producing vinyl and trans-vinylene termini. Subsequently, the effect of backbone inhomogeneity on the UV oxidative degradation of films made from both polyethylenes was investigated. The major functional group accumulated in the branched nm-CopolyPE film was carbonyl followed by carboxyl, then vinyl/ester, whereas that in the linear nm-HomoPE film was carboxyl. However, (carbonyl, carboxyl, vinyl, and ester) nm-CopolyPE film >> (carboxyl) nm-HomoPE film). The distributions of the tertiary C-H sites and methylene sequence length in the branched nm-CopolyPE film enhanced abstraction of H, decomposition of hydroperoxide group ROOH, and generation of carbonyl compounds as compared with those in the linear nm-HomoPE film. This clearly establishes the role played by the backbone inhomogeneity. The effect of short chain branches and sequence length distributions on peak melting temperature T pm, and most probably lamellar thickness L o, was

  16. Combined technology for clomazone herbicide wastewater treatment: three-dimensional packed-bed electrochemical oxidation and biological contact degradation.

    Science.gov (United States)

    Feng, Yujie; Liu, Junfeng; Zhu, Limin; Wei, Jinzhi

    2013-01-01

    The clomazone herbicide wastewater was treated using a combined technology composed of electrochemical catalytic oxidation and biological contact degradation. A new type of electrochemical reactor was fabricated and a Ti/SnO2 electrode was chosen as the anode in electrochemical-oxidation reactor and stainless steel as the cathode. Ceramic rings loaded with SnO2 were used as three-dimensional electrodes forming a packed bed. The operation parameters that might influence the degradation of organic contaminants in the clomazone wastewater were optimized. When the cell voltage was set at 30 V and the volume of particle electrodes was designed as two-thirds of the volume of the total reactor bed, the chemical oxygen demand (COD) removal rate could reach 82% after 120 min electrolysis, and the ratio of biochemical oxygen demand (BOD)/COD of wastewater increased from 0.12 to 0.38. After 12 h degradation with biological contact oxidation, the total COD removal rate of the combined technology reached 95%, and effluent COD was below 120 mg/L. The results demonstrated that this electrocatalytic oxidation method can be used as a pretreatment for refractory organic wastewater before biological treatment.

  17. Biological low pH Mn(II) oxidation in a manganese deposit influenced by metal-rich groundwater

    Science.gov (United States)

    Bohu, Tsing; Akob, Denise M.; Abratis, Michael; Lazar, Cassandre S.; Küsel, Kirsten

    2016-01-01

    The mechanisms, key organisms, and geochemical significance of biological low-pH Mn(II) oxidation are largely unexplored. Here, we investigated the structure of indigenous Mn(II)-oxidizing microbial communities in a secondary subsurface Mn oxide deposit influenced by acidic (pH 4.8) metal-rich groundwater in a former uranium mining area. Microbial diversity was highest in the Mn deposit compared to the adjacent soil layers and included the majority of known Mn(II)-oxidizing bacteria (MOB) and two genera of known Mn(II)-oxidizing fungi (MOF). Electron X-ray microanalysis showed that romanechite [(Ba,H2O)2(Mn4+,Mn3+)5O10] was conspicuously enriched in the deposit. Canonical correspondence analysis revealed that certain fungal, bacterial, and archaeal groups were firmly associated with the autochthonous Mn oxides. Eight MOB within the Proteobacteria, Actinobacteria, and Bacteroidetes and one MOF strain belonging to Ascomycota were isolated at pH 5.5 or 7.2 from the acidic Mn deposit. Soil-groundwater microcosms demonstrated 2.5-fold-faster Mn(II) depletion in the Mn deposit than adjacent soil layers. No depletion was observed in the abiotic controls, suggesting that biological contribution is the main driver for Mn(II) oxidation at low pH. The composition and species specificity of the native low-pH Mn(II) oxidizers were highly adapted to in situ conditions, and these organisms may play a central role in the fundamental biogeochemical processes (e.g., metal natural attenuation) occurring in the acidic, oligotrophic, and metalliferous subsoil ecosystems.

  18. Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaoka, K. [Okayama University Medical School, Okayama (Japan); Nomura, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Kojima, S. [Science University of Tokyo, Chiba (Japan)

    2000-05-01

    Excessive active oxygen produced in vivo by various causes is toxic. Accumulation of oxidation injuries due to excessive active causes cell and tissue injuries, inducing various pathologic conditions such as aging and carcinogenesis. On the other hand, there are chemical defense mechanisms in the body that eliminate active oxygen or repair damaged molecules, defending against resultant injury. It is interesting reports that appropriate oxidation stress activate the chemical biological defense mechanisms. In this study, to elucidate these phenomena and its mechanism by low dose radiation, we studied on the below subjects. Activation of chemical biological defense mechanisms by low dose radiation: (1) The effects radiation on lipid peroxide (LPO) levels in the organs, membrane fluidity and the superoxide dismutase (SOD) activity were examined in rats and rabbits. Rats were irradiated with low dose X-ray over their entire bodies, and rabbits inhaled vaporized radon spring water, which primarily emitted {alpha}-ray. The following results were obtained. Unlike high dose X-ray, low dose X-ray and radon inhalation both reduced LPO levels and made the state of the SH-group on membrane-bound proteins closer to that of juvenile animals, although the sensitivity to radioactivity varied depending on the age of the animals and among different organs and tissues. The SOD activity was elevated, suggesting that low dose X-ray and radon both activate the host defensive function. Those changes were particularly marked in the organs related to immune functions of the animals which received low dose X-ray, while they were particularly marked in the brain after radon inhalation. It was also found that those changes continued for longer periods after low dose X-irradiation. (2) Since SOD is an enzyme that mediates the dismutation of O{sub 2}- to H{sub 2}O{sub 2}, the question as to whether the resultant H{sub 2}O{sub 2} is further detoxicated into H{sub 2}O and O{sub 2} or not must

  19. Effects of concentration of Ag nanoparticles on surface structure and in vitro biological responses of oxide layer on pure titanium via plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ki Ryong; Kim, Yeon Sung; Kim, Gye Won [Department of Materials Science and Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of); Yang, Hae Woong [School of Materials Science and Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ko, Young Gun, E-mail: younggun@ynu.ac.kr [School of Materials Science and Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Shin, Dong Hyuk, E-mail: dhshin@hanyang.ac.kr [Department of Materials Science and Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of)

    2015-08-30

    Highlights: • Ag nanoparticles were embedded into the oxide surface without any compositional changes. • Oxide layer from the electrolyte with 0.1 g/l Ag nanoparticles could disinfect all bacteria. • With increasing Ag nanoparticles, bone-forming ability and cell proliferation rate decrease. - Abstract: This study was to investigate how Ag nanoparticles with various concentrations affect the surface structure and in vitro biological properties of oxide layers on the pure titanium produced by a plasma electrolytic oxidation (PEO) process. For this aim, PEO processes were carried out at an AC current density of 100 mA/cm{sup 2} for 300 s in potassium pyrophosphate (K{sub 4}P{sub 2}O{sub 7}) electrolytes containing 0, 0.1, 0.3 and 0.5 g/l Ag nanoparticles. Structural investigations using scanning electron microscopy evidenced that the oxide layers showed the successful incorporation of Ag nanoparticles, and the topographical deformation of the porous surface was found when the concentration of Ag nanoparticles was more than 0.1 g/l. Based on the anti-bacterial activity of all oxide layers, the Ag nanoparticles uniformly spread were of considerable importance in triggering the disinfection of E. coli bacteria. The bone forming abilities and cell (MC3T3-E1) proliferation rates of oxide layers produced in electrolytes containing 0 and 0.1 g/l Ag nanoparticles were higher than those containing 0.3 and 0.5 g/l Ag nanoparticles. Consequently, the oxide layer on pure titanium via PEO process in the electrolyte with 0.1 g/l Ag nanoparticles exhibited better the bioactivity accompanying the anti-bacterial activity.

  20. Experimental study on the treatment of dyeing wastewater by UV-Fenton oxidation process%UV-Fenton催化氧化处理印染废水的实验研究

    Institute of Scientific and Technical Information of China (English)

    朱洪涛

    2006-01-01

    对采用UV-Fenton催化氧化反应处理印染废水的主要影响因素及其处理效果的影响进行了实验研究.主要考察了FeSO4·7H2O的投加量和H2O2的投加量、pH、反应时间、投加方式等对色度和COD去除率的影响.正交实验结果显示,UV-Fenton催化氧化反应对色度和COD都有较好的去除效果.在0.1 mol/L FeSO4·7H2O的投加量为1.5 mL,30%H2O2的投加量为2 mL,pH为3,反应时间为3 h,H2O2分三次投加的情况下,色度去除率达到90.4%,COD去除率达到86.2%.同时与Fenton反应和UV-H2O2反应处理方法进行了比较实验,结果表明,UV-Fenton处理效果最佳.

  1. 紫外光照射纳米钛表面生物抗老化的体外研究%The study of biological aging resistance of nano titanium surface treated with UV irradiation in vitro

    Institute of Scientific and Technical Information of China (English)

    闵曦; 夏荣; 孙磊; 徐基亮; 孙子环

    2015-01-01

    Objective To study the impact of UV radiation on the physicochemical properties and biological activity of aging TiO2 nanotube surface. Methods Titanium plates treated by two-step anodization were stored in dark for eight weeks, sufficient to aging, and irradiated by UV for 48 h. Field emission scanning electron microscopy ( FESEM) , X-ray photoelectron spectroscopy ( XPS) and contact angle measurement were used to analyze the mi-crostructure, chemical elements and the contact angle of the surface of the fresh, aging, UV irradiation groups, re-spectively. Mouse bone marrow mesenchymal stem cells (MSCs) as cell lines were cultured on the treated titanium plates to determine the effect of modified titanium surface on the cell adhesion, proliferation and differentiation, fur-ther to evaluate biological differences among the three groups. Results FESEM displayed UV irradiation did not change the morphology of TiO2 nanotubes on the titanium surface. XPS showed that C elements on the surface of ag-ing group significantly increased after UV irradiation but restored to the level of fresh group by UV irritation. The contact angle analysis showed that the surface of age group was hydrophobic while the surface of UV irradiated group was superhydrophilic. In vitro cell culture showed that UV irritation was conducive to cell adhesion, proliferation and differentiation. Conclusion UV radiation can remove hydrocarbon contamination on surface of titanium, im-prove the surface hydrophilicity, and delay the bioactive decrease of titanium-based TiO2 nanotube surface by time factors.%目的:研究紫外光照射对老化TiO2纳米管表面理化性质和生物活性的影响。方法两步阳极氧化后的钛片避光保存8周,使其充分老化,紫外光照射48 h;利用场发射扫描电镜(FESEM)、X射线光电子能谱(XPS)、接触角测量仪分析新鲜、老化及紫外光照射组钛片表面微观结构、化学元素和接触角变化;以小鼠骨

  2. 葡萄叶片茋类物质积累对UV-C氧化胁迫的响应作用%The Role of Stilbenes Accumulation in Response to Oxidative Stress by UV-C in Grape Leaves

    Institute of Scientific and Technical Information of China (English)

    李月荣; 颜欢; 张波; 黄方爱; 杨晓燕; 李荣飞

    2015-01-01

    [目的]紫外引起葡萄叶片茋类物质白藜芦醇积累是一种常见的辐射效应,研究积累与UV-C引起的氧化胁迫关系.[方法]采用UV-C对离体红地球葡萄叶片进行胁迫;应用荧光照相与HPLC分析茋类物质变化特征,利用RT-PCR分析其生物合成途径基因表达规律,DAB检测叶片活性氧水平,分光光度法测定丙二醛水平,依文思蓝检测叶片细胞死亡程度.[结果]以22.5(w·h)/cm2 UV-C辐射叶片后白藜芦醇的含量最大,达到158 μg/g鲜重.同一叶片左右差异明显,辐射处理一侧茋类物质含量、活性氧水平和细胞死亡程度明显高于未处理一侧;经辐射后的叶片中的MDA含量高于对照组;加抗氧化剂CAT和NAC可明显降低UV-C对白藜芦醇诱导效果.[结论]UV-C辐射导致离体红地球葡萄叶片氧化胁迫受损,其变化在空间和时间上与茋类物质白藜芦醇积累密切相关.

  3. Stability of Commercial Small-Sized Cerium Oxide in the Presence of Biological Material: Dilucidating Relationships between Reactivity and Toxicity of Nanomaterials

    Science.gov (United States)

    Cervini-Silva, J.; Gilbert, B.; Fernandez-Lomelin, P.; Guzman-Mendoza, J.; Chavira, E.

    2007-05-01

    the transformation of biomolecules (as % carbon) with decreasing CeO2 particle diameter (13 < d < 84 Å), which substantiates an intimate relation between CeO2 unit cell expansion and reactivity towards organics susceptible to undergo redox transformations. As shown by C and Ce spectroscopy, organic polymers that form because of oxidation are distributed next to the mineral surface and its occurrence is coupled to Ce reduction-oxidation. As evidenced by DSL and UV experiments conducted for the pH 2 to 8 range, the aggregation behavior of nanoCeO2 is susceptible to pH variations imposed because the presence of biological moieties itself over solid concentration.

  4. Ferromagnetic resonance for the quantification of superparamagnetic iron oxide nanoparticles in biological materials

    Directory of Open Access Journals (Sweden)

    Lionel F Gamarra

    2010-03-01

    Full Text Available Lionel F Gamarra1,2, Antonio J daCosta-Filho3, Javier B Mamani1, Rita de Cassia Ruiz4, Lorena F Pavon1, Tatiana T Sibov1, Ernanni D Vieira3, André C Silva1, Walter M Pontuschka5, Edson Amaro Jr1,21Instituto Israelita de Ensino e Pesquisa Albert Einstein, IIEPAE, São Paulo, Brazil; 2Instituto de Radiologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil; 3Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil; 4Instituto Butantan, São Paulo, Brazil; 5Instituto de Física, Universidade de São Paulo, São Paulo, BrazilAbstract: The aim of the present work is the presentation of a quantification methodology for the control of the amount of superparamagnetic iron oxide nanoparticles (SPIONs administered in biological materials by means of the ferromagnetic resonance technique (FMR applied to studies both in vivo and in vitro. The in vivo study consisted in the analysis of the elimination and biodistribution kinetics of SPIONs after intravenous administration in Wistar rats. The results were corroborated by X-ray fluorescence. For the in vitro study, a quantitative analysis of the concentration of SPIONs bound to the specific AC133 monoclonal antibodies was carried out in order to detect the expression of the antigenic epitopes (CD133 in stem cells from human umbilical cord blood. In both studies FMR has proven to be an efficient technique for the SPIONs quantification per volume unit (in vivo or per labeled cell (in vitro.Keywords: quantification, FMR, ferrofluid, biodistribution, nanoparticles

  5. Chromium oxide (51Cr2O3 used as biological marker was not absorbed by fish

    Directory of Open Access Journals (Sweden)

    G.Z. Sakita

    2015-06-01

    Full Text Available The aim of this study was to evaluate the rate absorption of radio-labeled chromium oxide (51Cr2O3, used as biological marker in nutrition studies with Nile tilapia Oreochromis niloticus. An experimental diet with approximately 58 µCi of specific activity of the element was encapsulated and fed daily to 35 adult Nile tilapia; a group of 35 fish was used as control feeding on a basal diet. At the beginning of the experiment five fish from each group were randomly selected and blood samples were drawn from control (BC and experimental fish (BE. Fish were then euthanized by anesthetic overdoses and samples of the liver tissue (LT, renal tissue (RT, stomach without content (S, intestine without content (I, gills tissue (GT, muscle tissue (fillet; MT, visceral fat (VF, content of the digestive tract (CTDE and water aquarium were collected from the experimental fish. The procedure was repeated daily for one week. Simple linear regressions were adjusted - days of collection vs. determination coefficients, and were established for statistical comparisons of the measured activity of 51Cr readings in sampled blood and tissues (logarithmic transformation for samples of the control and experimental fish. No differences (P>0.05 were detected between samples from BC fish and BE, RT, VF, MT and LT of treated fish, but samples of GT, I, S, CTDE and WA from the tanks holding fish which received the experimental diet differed from control (P<0.05. The experimental results indicate that the trivalent chromium in the form of 51Cr2O3 was not significantly absorbed by the gastrointestinal tract, gills or another possible route of absorption under these experimental conditions and with Nile tilapia. Therefore, this marker was shown to be inert and can be safely used in nutrition studies.

  6. Robust and economical multi-sample, multi-wavelength UV/vis absorption and fluorescence detector for biological and chemical contamination

    CERN Document Server

    Lu, Peter J; Macarthur, James B; Sims, Peter A; Ma, Hongshen; Slocum, Alexander H

    2012-01-01

    We present a portable multi-channel, multi-sample UV/vis absorption and fluorescence detection device, which has no moving parts, can operate wirelessly and on batteries, interfaces with smart mobile phones or tablets, and has the sensitivity of commercial instruments costing an order of magnitude more. We use UV absorption to measure the concentration of ethylene glycol in water solutions at all levels above those deemed unsafe by the United States Food and Drug Administration; in addition we use fluorescence to measure the concentration of d-glucose. Both wavelengths can be used concurrently to increase measurement robustness and increase detection sensitivity. Our small robust economical device can be deployed in the absence of laboratory infrastructure, and therefore may find applications immediately following natural disasters, and in more general deployment for much broader-based testing of food, agricultural and household products to prevent outbreaks of poisoning and disease.

  7. Nitric oxide and redox regulation in the liver: Part I. General considerations and redox biology in hepatitis.

    Science.gov (United States)

    Diesen, Diana L; Kuo, Paul C

    2010-07-01

    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are created in normal hepatocytes and are critical for normal physiologic processes, including oxidative respiration, growth, regeneration, apoptosis, and microsomal defense. When the levels of oxidation products exceed the capacity of normal antioxidant systems, oxidative stress occurs. This type of stress, in the form of ROS and RNS, can be damaging to all liver cells, including hepatocytes, Kupffer cells, stellate cells, and endothelial cells, through induction of inflammation, ischemia, fibrosis, necrosis, apoptosis, or through malignant transformation by damaging lipids, proteins, and/or DNA. In Part I of this review, we will discuss basic redox biology in the liver, including a review of ROS, RNS, and antioxidants, with a focus on nitric oxide as a common source of RNS. We will then review the evidence for oxidative stress as a mechanism of liver injury in hepatitis (alcoholic, viral, nonalcoholic). In Part II of this review, we will review oxidative stress in common pathophysiologic conditions, including ischemia/reperfusion injury, fibrosis, hepatocellular carcinoma, iron overload, Wilson's disease, sepsis, and acetaminophen overdose. Finally, biomarkers, proteomic, and antioxidant therapies will be discussed as areas for future therapeutic interventions.

  8. Nitric oxide and redox regulation in the liver: part II. Redox biology in pathologic hepatocytes and implications for intervention.

    Science.gov (United States)

    Diesen, Diana L; Kuo, Paul C

    2011-05-01

    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are created in normal hepatocytes and are critical for normal physiologic processes, including oxidative respiration, growth, regeneration, apoptosis, and microsomal defense. When the levels of oxidation products exceed the capacity of normal antioxidant systems, oxidative stress occurs. This type of stress, in the form of ROS and RNS, can be damaging to all liver cells, including hepatocytes, Kupffer cells, stellate cells, and endothelial cells, through induction of inflammation, ischemia, fibrosis, necrosis, apoptosis, or through malignant transformation by damaging lipids, proteins, and/or DNA. In Part I of this review, we will discuss basic redox biology in the liver, including a review of ROS, RNS, and antioxidants, with a focus on nitric oxide as a common source of RNS. We will then review the evidence for oxidative stress as a mechanism of liver injury in hepatitis (alcoholic, viral, nonalcoholic). In Part II of this review, we will review oxidative stress in common pathophysiologic conditions, including ischemia/reperfusion injury, fibrosis, hepatocellular carcinoma, iron overload, Wilson's disease, sepsis, and acetaminophen overdose. Finally, biomarkers, proteomic, and antioxidant therapies will be discussed as areas for future therapeutic interventions.

  9. The oxidation of methionine-54 of epoetinum alfa does not affect molecular structure or stability, but does decrease biological activity.

    Science.gov (United States)

    Labrenz, Steven R; Calmann, Melissa A; Heavner, George A; Tolman, Glen

    2008-01-01

    Erythropoietin therapy is used to treat severe anemia in renal failure and chemotherapy patients. One of these therapies based on recombinant human erythropoietin is marketed under the trade name of EPREX and utilizes epoetinum alfa as the active pharmaceutical ingredient. The effect of oxidation of methionine-54 on the structure and stability of the erythropoietin molecule has not been directly tested. We have observed partial and full chemical oxidation of methionine-54 to methionine-54 sulfoxide, accomplished using tert-Butylhydroperoxide and hydrogen peroxide, respectively. A blue shift in the fluorescence center of spectral mass wavelength was observed as a linear response to the level of methionine sulfoxide in the epoetinum alfa molecule, presumably arising from a local change in the environment near tryptophan-51, as supported by potassium iodide quenching studies. Circular dichroism studies demonstrated no change in the folded structure of the molecule with methionine oxidation. The thermal unfolding profiles of partial and completely oxidized epoetinum alfa overlap, with a T(m) of 49.5 degrees C across all levels of methionine sulfoxide content. When the protein was tested for activity, a decrease in biological activity was observed, correlating with methionine sulfoxide levels. An allosteric effect between Met54, Trp51, and residues involved in receptor binding is proposed. These results indicate that methionine oxidation has no effect on the folded structure and global thermodynamic stability of the recombinant human erythropoietin molecule. Oxidation can affect potency, but only at levels significantly in excess of those seen in EPREX.

  10. Modeling nitrous oxide production during biological nitrogen removal via nitrification and denitrification: extensions to the general ASM models.

    Science.gov (United States)

    Ni, Bing-Jie; Ruscalleda, Maël; Pellicer-Nàcher, Carles; Smets, Barth F

    2011-09-15

    Nitrous oxide (N(2)O) can be formed during biological nitrogen (N) removal processes. In this work, a mathematical model is developed that describes N(2)O production and consumption during activated sludge nitrification and denitrification. The well-known ASM process models are extended to capture N(2)O dynamics during both nitrification and denitrification in biological N removal. Six additional processes and three additional reactants, all involved in known biochemical reactions, have been added. The validity and applicability of the model is demonstrated by comparing simulations with experimental data on N(2)O production from four different mixed culture nitrification and denitrification reactor study reports. Modeling results confirm that hydroxylamine oxidation by ammonium oxidizers (AOB) occurs 10 times slower when NO(2)(-) participates as final electron acceptor compared to the oxic pathway. Among the four denitrification steps, the last one (N(2)O reduction to N(2)) seems to be inhibited first when O(2) is present. Overall, N(2)O production can account for 0.1-25% of the consumed N in different nitrification and denitrification systems, which can be well simulated by the proposed model. In conclusion, we provide a modeling structure, which adequately captures N(2)O dynamics in autotrophic nitrification and heterotrophic denitrification driven biological N removal processes and which can form the basis for ongoing refinements.

  11. Some ozone advanced oxidation processes to improve the biological removal of selected pharmaceutical contaminants from urban wastewater.

    Science.gov (United States)

    Espejo, Azahara; Aguinaco, Almudena; Amat, Ana M; Beltrán, Fernando J

    2014-01-01

    Removal of nine pharmaceutical compounds--acetaminophen (AAF), antipyrine (ANT), caffeine (CAF), carbamazepine (CRB), diclofenac (DCF), hydrochlorothiazide (HCT), ketorolac (KET), metoprolol (MET) and sulfamethoxazole (SMX)-spiked in a primary sedimentation effluent of a municipal wastewater has been studied with sequential aerobic biological and ozone advanced oxidation systems. Combinations of ozone, UVA black light and Fe(III) or Fe3O4 constituted the chemical systems. During the biological treatment (hydraulic residence time, HRT = 24 h), only AAF and CAF were completely eliminated, MET, SMX and HCT reached partial removal rates and the rest of compounds were completely refractory. With any ozone advanced oxidation process applied, the remaining pharmaceuticals disappear in less than 10 min. Fe3O4 or Fe(III) photocatalytic ozonation leads to 35% mineralization compared to 13% reached during ozonation alone after about 30-min reaction. Also, biodegradability of the treated wastewater increased 50% in the biological process plus another 150% after the ozonation processes. Both untreated and treated wastewater was non-toxic for Daphnia magna (D. magna) except when Fe(III) was used in photocatalytic ozonation. In this case, toxicity was likely due to the ferryoxalate formed in the process. Kinetic information on ozone processes reveals that pharmaceuticals at concentrations they have in urban wastewater are mainly removed through free radical oxidation.

  12. Semiconductor Metal Oxide Sensors in Water and Water Based Biological Systems

    Directory of Open Access Journals (Sweden)

    Marina V. Strobkova

    2003-10-01

    Full Text Available The results of implementation of In2O3-based semiconductor sensors for oxygen concentration evaluation in water and the LB-nutrient media (15.5 g/l Luria Broth Base, Miller (Sigma, Lot-1900 and NaCl without bacteria and with E.coli bacteria before and after UV-irradiation are presented.

  13. Photocatalytic Oxidation Process (UV/H2O2/ZnO in the treatment and sterilization of dairy wastewater - doi: 10.4025/actascitechnol.v35i1.11132

    Directory of Open Access Journals (Sweden)

    Priscila de Abreu

    2013-01-01

    Full Text Available Advanced Oxidation Processes (AOP have attracted much interest of scientific and industrial communities. Therefore, this process was employed experimentally to determine its efficacy in treating dairy effluents. For this, it was employed an artificial light reactor using photolysis (UV, hydrogen peroxide (H2O2 as an oxidant, and zinc oxide (ZnO as an alternative catalyst. The variables studied in the photocatalysis were: H2O2, ZnO, under different values of pH, both in relation to the interferences with the reaction rate and with the process efficiency. First order differential equations were applied in determining the degradation rate over the hydraulic retention time (HRT; the F-test and the signal: noise ratio comparison were used to test the significance of variables. The AOP using photolysis UV, H2O2 and ZnO was effective in COD removal with 80% efficiency. As for the sterilization, in terms of total and fecal coliforms the efficiency was 100%, with the most probable number of total and fecal coliforms (MPN 100 mL-1 equal to zero. A catalyst/oxidant/pH ratio was observed at 1 g  30 mL-1 4-1 for a better kinetic-chemical reaction, for 1 hour lighting.  

  14. Elucidation of mechanisms in manganese and iron based oxidation catalysis: Mechanistic insights and development of novel approaches applied to transition metal catalyzed oxidations catalysis

    OpenAIRE

    Angelone, Davide

    2016-01-01

    Oxidation chemistry is central to life and to the modern chemical industry and hence understanding chemical oxidation is essential to developing new processes and elucidating biological oxidation mechanisms. Elucidating mechanisms in inorganic oxidation catalysis and simultaneously developing new tools to do so is the theme of this thesis. Spectroscopic techniques, especially Raman and UV-vis absorption, are used, together with Density Functional theory (DFT), to observe and characterise the ...

  15. Does dissolved organic carbon regulate biological methane oxidation in semiarid soils?

    Science.gov (United States)

    Sullivan, Benjamin W; Selmants, Paul C; Hart, Stephen C

    2013-07-01

    In humid ecosystems, the rate of methane (CH4 ) oxidation by soil-dwelling methane-oxidizing bacteria (MOB) is controlled by soil texture and soil water holding capacity, both of which limit the diffusion of atmospheric CH4 into the soil. However, it remains unclear whether these same mechanisms control CH4 oxidation in more arid soils. This study was designed to measure the proximate controls of potential CH4 oxidation in semiarid soils during different seasons. Using a unique and well-constrained 3-million-year-old semiarid substrate age gradient, we were able to hold state factors constant while exploring the relationship between seasonal potential CH4 oxidation rates and soil texture, soil water holding capacity, and dissolved organic carbon (DOC). We measured unexpectedly higher rates of potential CH4 oxidation in the wet season than the dry season. Although other studies have attributed low CH4 oxidation rates in dry soils to desiccation of MOB, we present several lines of evidence that this may be inaccurate. We found that soil DOC concentration explained CH4 oxidation rates better than soil physical factors that regulate the diffusion of CH4 from the atmosphere into the soil. We show evidence that MOB facultatively incorporated isotopically labeled glucose into their cells, and MOB utilized glucose in a pattern among our study sites that was similar to wet-season CH4 oxidation rates. This evidence suggests that DOC, which is utilized by MOB in other environments with varying effects on CH4 oxidation rates, may be an important regulator of CH4 oxidation rates in semiarid soils. Our collective understanding of the facultative use of DOC by MOB is still in its infancy, but our results suggest it may be an important factor controlling CH4 oxidation in soils from dry ecosystems.

  16. Involvement of Nitric Oxide on Bothropoides insularis Venom Biological Effects on Murine Macrophages In Vitro.

    Directory of Open Access Journals (Sweden)

    Ramon R P P B de Menezes

    Full Text Available Viperidae venom has several local and systemic effects, such as pain, edema, inflammation, kidney failure and coagulopathy. Additionally, bothropic venom and its isolated components directly interfere on cellular metabolism, causing alterations such as cell death and proliferation. Inflammatory cells are particularly involved in pathological envenomation mechanisms due to their capacity of releasing many mediators, such as nitric oxide (NO. NO has many effects on cell viability and it is associated to the development of inflammation and tissue damage caused by Bothrops and Bothropoides venom. Bothropoides insularis is a snake found only in Queimada Grande Island, which has markedly toxic venom. Thus, the aim of this work was to evaluate the biological effects of Bothropoides insularis venom (BiV on RAW 264.7 cells and assess NO involvement. The venom was submitted to colorimetric assays to identify the presence of some enzymatic components. We observed that BiV induced H2O2 production and showed proteolytic and phospholipasic activities. RAW 264.7 murine macrophages were incubated with different concentrations of BiV and then cell viability was assessed by MTT reduction assay after 2, 6, 12 and 24 hours of incubation. A time- and concentration-dependent effect was observed, with a tendency to cell proliferation at lower BiV concentrations and cell death at higher concentrations. The cytotoxic effect was confirmed after lactate dehydrogenase (LDH measurement in the supernatant from the experimental groups. Flow cytometry analyses revealed that necrosis is the main cell death pathway caused by BiV. Also, BiV induced NO release. The inhibition of both proliferative and cytotoxic effects with L-NAME were demonstrated, indicating that NO is important for these effects. Finally, BiV induced an increase in iNOS expression. Altogether, these results demonstrate that B. insularis venom have proliferative and cytotoxic effects on macrophages, with

  17. UV/Fe3 + Photocatalytic Oxidation Process for Treatment of Refuse Landfill Leachate%UV/Fe3+光催化氧化处理垃圾渗滤液

    Institute of Scientific and Technical Information of China (English)

    裴华; 曾庆福; 章北平; 王宗平

    2003-01-01

    研究了UV/Fe3+络合物光催化氧化处理垃圾渗滤液的效果,重点比较了Fe3++光、Fe3++C2O2-4+光、Fe3++H2O2+C2O2-4+光、Fe3++H2O2+光与直接光照等方法对渗滤液中COD、BOD5、TOC和NH3-N的去除效果.

  18. Inflammation, gene mutation and photoimmunosuppression in response to UVR-induced oxidative damage contributes to photocarcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, Gary M. [Dermatology Research Laboratories, Division of Medicine, Melanoma and Skin Cancer Research Institute, Royal Prince Alfred Hospital at the University of Sydney, Sydney, NSW (Australia)]. E-mail: garyh@med.usyd.edu.au

    2005-04-01

    Ultraviolet (UV) radiation causes inflammation, gene mutation and immunosuppression in the skin. These biological changes are responsible for photocarcinogenesis. UV radiation in sunlight is divided into two wavebands, UVB and UVA, both of which contribute to these biological changes, and therefore probably to skin cancer in humans and animal models. Oxidative damage caused by UV contributes to inflammation, gene mutation and immunosuppression. This article reviews evidence for the hypothesis that UV oxidative damage to these processes contributes to photocarcinogenesis. UVA makes a larger impact on oxidative stress in the skin than UVB by inducing reactive oxygen and nitrogen species which damage DNA, protein and lipids and which also lead to NAD+ depletion, and therefore energy loss from the cell. Lipid peroxidation induces prostaglandin production that in association with UV-induced nitric oxide production causes inflammation. Inflammation drives benign human solar keratosis (SK) to undergo malignant conversion into squamous cell carcinoma (SCC) probably because the inflammatory cells produce reactive oxygen species, thus increasing oxidative damage to DNA and the immune system. Reactive oxygen or nitrogen appears to cause the increase in mutational burden as SK progress into SCC in humans. UVA is particularly important in causing immunosuppression in both humans and mice, and UV lipid peroxidation induced prostaglandin production and UV activation of nitric oxide synthase is important mediators of this event. Other immunosuppressive events are likely to be initiated by UV oxidative stress. Antioxidants have also been shown to reduce photocarcinogenesis. While most of this evidence comes from studies in mice, there is supporting evidence in humans that UV-induced oxidative damage contributes to inflammation, gene mutation and immunosuppression. Available evidence implicates oxidative damage as an important contributor to sunlight-induced carcinogenesis in humans.

  19. Inflammation, gene mutation and photoimmunosuppression in response to UVR-induced oxidative damage contributes to photocarcinogenesis.

    Science.gov (United States)

    Halliday, Gary M

    2005-04-01

    Ultraviolet (UV) radiation causes inflammation, gene mutation and immunosuppression in the skin. These biological changes are responsible for photocarcinogenesis. UV radiation in sunlight is divided into two wavebands, UVB and UVA, both of which contribute to these biological changes, and therefore probably to skin cancer in humans and animal models. Oxidative damage caused by UV contributes to inflammation, gene mutation and immunosuppression. This article reviews evidence for the hypothesis that UV oxidative damage to these processes contributes to photocarcinogenesis. UVA makes a larger impact on oxidative stress in the skin than UVB by inducing reactive oxygen and nitrogen species which damage DNA, protein and lipids and which also lead to NAD+ depletion, and therefore energy loss from the cell. Lipid peroxidation induces prostaglandin production that in association with UV-induced nitric oxide production causes inflammation. Inflammation drives benign human solar keratosis (SK) to undergo malignant conversion into squamous cell carcinoma (SCC) probably because the inflammatory cells produce reactive oxygen species, thus increasing oxidative damage to DNA and the immune system. Reactive oxygen or nitrogen appears to cause the increase in mutational burden as SK progress into SCC in humans. UVA is particularly important in causing immunosuppression in both humans and mice, and UV lipid peroxidation induced prostaglandin production and UV activation of nitric oxide synthase is important mediators of this event. Other immunosuppressive events are likely to be initiated by UV oxidative stress. Antioxidants have also been shown to reduce photocarcinogenesis. While most of this evidence comes from studies in mice, there is supporting evidence in humans that UV-induced oxidative damage contributes to inflammation, gene mutation and immunosuppression. Available evidence implicates oxidative damage as an important contributor to sunlight-induced carcinogenesis in humans.

  20. Study on UV/H2O2 pre-oxidation for treating zinc-nickel alloys electroplating wastewater%UV/H2O2预氧化处理锌镍合金电镀废水的研究

    Institute of Scientific and Technical Information of China (English)

    李金成; 郭海丽; 雷铠玮; 夏文香

    2016-01-01

    锌镍合金电镀是近10年发展起来的一种新型电镀技术,由于电镀过程添加了大量配位剂及螯合剂,使废水中的锌和镍离子以络合形式存在,无法采用传统的加碱沉淀方式直接处理。研究了UV/H2O2预氧化对这类合金电镀废水的处理效果,分析了UV照射时间、H2O2投加量、原水pH以及操作方式对处理效果的影响。结果表明UV/H2O2预氧化可以有效地氧化分解合金电镀废水中的络合物,预处理出水经加碱沉淀后,锌和镍的去除率分别可达95.3%、98.7%,达到GB 21900—2008《电镀污染物排放标准》的要求。%Zinc-nickel alloys electroplate is a new technology developed in recent 10 years. Since a large amount of complexing agent and chelating agent were added in the electroplating process ,zinc and nickel ions in wastewater exist in complex form,and it is impossible for it to be treated directly by conventional method of precipitation with alkali. The treatment effect of UV/H2O2 pre-oxidation method on this kind of alloy electroplating wastewater has been studied. The influences of UV irradiation time, dosage of H2O2,pH of original wastewater and operation style on the treatment effect are analyzed. The results show that UV/H2O2 pre-oxidation can effectively oxidize and decompose the complex compounds in alloy electroplating wastewater. After the effluent of pre-treatment has been precipitated with alkali,the removing rates of zinc and nickel can reach 95.3% and 98.7%,respectively,meeting the requirements specified in the Emission Standard of Pollutants for Electroplating (GB 21900—2008).

  1. Synthesis, spectral (FT-IR, UV-visible, NMR) features, biological activity prediction and theoretical studies of 4-Amino-3-(4-hydroxybenzyl)-1H-1,2,4-triazole-5(4H)-thione and its tautomer

    Science.gov (United States)

    Srivastava, Ambrish Kumar; Kumar, Abhishek; Misra, Neeraj; Manjula, P. S.; Sarojini, B. K.; Narayana, B.

    2016-03-01

    Triazole compounds constitute an important class of organic chemistry due to their various biological and corrosion inhibition activities. The synthesis scheme of a new triazole compound namely, 4-Amino-3-(4-hydroxybenzyl)-1H-1,2,4-triazole-5(4H)-thione (4AHT) has been theoretically analyzed. Our density functional theory (DFT) based calculations show that the synthesis of 4AHT is energetically feasible at the room temperature as the reaction is exothermic, spontaneous as well as favored in forward direction. The calculated bond-lengths are found to be in good agreement with corresponding crystallographic values. We have considered two possible tautomers of 4AHT viz. thione and thiol forms. The FT-IR (KBr disc), UV-visible (ethanol) and 1H-NMR (DMSO) spectra of 4AHT have been recorded. The vibrational modes have been assigned on the basis of their potential energy distributions and scaled wavenumbers agree well with the FT-IR wavenumbers. Time dependent DFT calculations are performed to analyze the electronic transitions for various excited states which reproduce the experimental peak observed in UV-visible spectrum. Using gauge independent atomic orbital method 1H-NMR chemical shifts have been calculated and correlated with the experimental chemical shifts with the linear correlation coefficient of 0.9453. Our spectral analyses reveal the dominance of thione over thiol form of 4AHT. The chemical reactivity of 4AHT has been discussed by molecular electrostatic potential surface as well as various electronic parameters. The biological activities of 4AHT have also been explored theoretically and it has been found that the title molecule can act as a potential inhibitor of cyclin-dependent kinase 5 enzyme. These findings may guide the synthesis and design of new triazole compounds with interesting biological activity.

  2. Study on the Decomposition of Phenol with the Method of ClO2/UV Oxidization%ClO2/UV氧化法降解苯酚的研究

    Institute of Scientific and Technical Information of China (English)

    曹福; 朱莉

    2011-01-01

    [ Objective] The method of the phenol in wastewater was decomposed with the UV photocatalytic method combined with chlorine dioxide( ClO2 ) treatment was studied. [ Method] The effect of the adding amount of ClO2 as oxidant, the irradiation time of UV as assistance,the pH of the wastewater and other factors on the decomposition of phenol was experimented. [ Result ] The degradation rate of phenol in wastewater could reach up to 99.5% while the pH was 8, the adding amount of ClO2 was 140 mg/L and the irradiation time of UV was 30 minutes. Under the same condition, the combination of ClO2 and UV was much better and faster than that of single use of ClO2 or UV. [ Conclusion] The method of ClO2/UV oxidization in treatment of the wastewater containing phenol was effective.%[目的]研究UV光催化联合CIO降解水溶液中苯酚的方法.[方法]以模拟苯酚废水为处理对象,CIO为氧化剂,UV作为辅助手段,考察CIO/UV氧化处理苯酚废水工艺中CIO投加量、UV辐照时闻、废水pH等因素对苯酚处理效果的影响.[结果]处理质量浓度为100 mg/L的苯酚废水.pH在8左右,CIO投加量为140 mg/L,UV辐照时间为30 min的条件下,处理效果最好,苯酚去除率高达99.6%.并且在相同的处理条件下,CIO/UV氧化苯酚的效率明显高于单-CIO或UV法,同时大大缩短了反应时间.[结论]CIO/UV氧化法是一种行之有效的含酚废水的处理方法.

  3. Oxidative Damage to Nucleic Acids and Benzo(apyrene-7,8-diol-9,10-epoxide-DNA Adducts and Chromosomal Aberration in Children with Psoriasis Repeatedly Exposed to Crude Coal Tar Ointment and UV Radiation

    Directory of Open Access Journals (Sweden)

    Lenka Borska

    2014-01-01

    Full Text Available The paper presents a prospective cohort study. Observed group was formed of children with plaque psoriasis (n=19 treated by Goeckerman therapy (GT. The study describes adverse (side effects associated with application of GT (combined exposure of 3% crude coal tar ointment and UV radiation. After GT we found significantly increased markers of oxidative stress (8-hydroxy-2′-deoxyguanosine, 8-hydroxyguanosine, and 8-hydroxyguanine, significantly increased levels of benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE DNA adducts (BPDE-DNA, and significantly increased levels of total number of chromosomal aberrations in peripheral lymphocytes. We found significant relationship between (1 time of UV exposure and total number of aberrated cells and (2 daily topical application of 3% crude coal tar ointment (% of body surface and level of BPDE-DNA adducts. The findings indicated increased hazard of oxidative stress and genotoxic effects related to the treatment. However, it must be noted that the oxidized guanine species and BPDE-DNA adducts also reflect individual variations in metabolic enzyme activity (different extent of bioactivation of benzo[a]pyrene to BPDE and overall efficiency of DNA/RNA repair system. The study confirmed good effectiveness of the GT (significantly decreased PASI score.

  4. Study of degradation of trace benzene in water by 185 nm UV light and oxidation technique%185nm紫外光/氧化协同降解水体中微量苯的研究

    Institute of Scientific and Technical Information of China (English)

    陆军; 朱承驻

    2011-01-01

    The degradation of trace benzene in water was studied by using 185 nm UV light and oxidation technique. The influence of concentration of benzene, degradation time, pH value of solution, and oxidants on the degradation of benzene was investigated. The degradation products were analyzed by using GC/MS method and the degradation mechanism was presented. The results showed that the trace benzene was effectively degradated by 185 nm UV light and oxidation technique, and after treating for 3 min, the degradation efficiency of CODCr in benzene solution reached above 95% when K2S2O8 was added.%文章利用185 nm紫外光/氧化协同降解技术对水体中微量苯的降解情况进行了研究,考察了溶液中苯的质量浓度、光解时间、溶液pH值以及加入氧化剂等对苯降解的影响,对光解产物进行了分析,并对其降解机理进行了探讨.研究结果表明,该技术能有效降解水体中微量苯,处理3 min时加入K2SO8的苯溶液的CODcr的去除率可达到95%以上.

  5. ClO2/UV催化氧化处理酚醛废水的研究%Study on treatment of phenolic wastewater with ClO2/UV catalytic oxidation method

    Institute of Scientific and Technical Information of China (English)

    王宏力; 薄新党; 杨晓刚; 范少文

    2012-01-01

    ClO2/ UV process is used in the catalytic oxidative degradation of phenolic wastewater,in this study. The influence of amount of ClO2 ,pH value of initial solution,catalyst dosage and UV irradiation time, etc. ,is investigated. The optimal catalytic oxidative conditions are shown as follows ;35 mL of ClO2 solution ,3 g of catalyst dosage ,2 of the pH value of initial solution and 40 minutes of the reaction time. The better degradation effect can be achieved under the optimal conditions. The removal rate of phenol and COD are 86. 87% and 71. 83% respectively. Besides that, introduction of UV is beneficial to the degradation of wastewater. Under the UV/ ClO2 combined catalytic oxidation condition, the removal rate of phenol and COD can reach 92. 07% and 84. 46% , respectively, after 50 minutes of reaction.%以ClO2/UV工艺对酚醛废水进行催化氧化降解,考察ClO2加入量、初始溶液pH、催化剂投加量、紫外照射时间等因素对废水处理效果的影响,确定适宜催化氧化反应工艺条件.实验结果表明,在250 mL酚醛废水中,ClO2溶液加入量为35mL,催化剂投加量为3 g,废水初始pH为2,反应时间为40 min时,处理效果较高,苯酚、COD去除率分别为86.87%和71.83%.UV的引入有利于废水的降解,在UV/ClO2联合工艺条件下,反应50 min,苯酚、COD去除率分别达到92.07%和84.46%.

  6. DNA Mismatch Repair and Oxidative DNA Damage: Implications for Cancer Biology and Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bridge, Gemma; Rashid, Sukaina; Martin, Sarah A., E-mail: sarah.martin@qmul.ac.uk [Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ (United Kingdom)

    2014-08-05

    Many components of the cell, including lipids, proteins and both nuclear and mitochondrial DNA, are vulnerable to deleterious modifications caused by reactive oxygen species. If not repaired, oxidative DNA damage can lead to disease-causing mutations, such as in cancer. Base excision repair and nucleotide excision repair are the two DNA repair pathways believed to orchestrate the removal of oxidative lesions. However, recent findings suggest that the mismatch repair pathway may also be important for the response to oxidative DNA damage. This is particularly relevant in cancer where mismatch repair genes are frequently mutated or epigenetically silenced. In this review we explore how the regulation of oxidative DNA damage by mismatch repair proteins may impact on carcinogenesis. We discuss recent studies that identify potential new treatments for mismatch repair deficient tumours, which exploit this non-canonical role of mismatch repair using synthetic lethal targeting.

  7. UV Bandpass Optical Filter for Microspectometers

    NARCIS (Netherlands)

    Correia, J.H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in t

  8. Comparison of the biological behaviour of morphine and its N-oxides in rats

    Energy Technology Data Exchange (ETDEWEB)

    Gurkan, E.; Demirel, B.; Ozker, K. (Cekmece Nuclear Research and Training Center, Istanbul (Turkey))

    1982-04-01

    /sup 14/C labelled morphine and morphine N-oxide solutions are injected into rats for the in vivo detection and comparison of morphine N-oxides, the natural presence of which in Papaver somniferum L. was proved by us in an earlier work /1/ and morphine itself and the distributions of these two substances in the kidneys, liver, blood and urine of the injected animals are investigated, in various time intervals.

  9. Formation and colloidal behaviour of elemental sulphur produced from the biological oxidation of hydrogensulphide.

    OpenAIRE

    Janssen, A.J.H.

    1996-01-01

    The formation and aggregation of elemental sulphur from the microbiological oxidation of hydrogensulphide (H 2 S) by a mixed population of aerobic Thiobacillus -like bacteria has been investigated. Sulphide is formed during the anaerobic treatment of wastewaters which contain oxidized sulphur compounds such as thiosulphate, sulphite and sulphate. This sulphide has to be removed from the effluent solution of anaerobic reactors because of its detrimental characteristics e.g. toxicity, corrosive...

  10. Oxidation of polyvinylpyrrolidone and an ethoxylate surfactant in phase-inversion wastewater.

    Science.gov (United States)

    Loraine, Gregory A

    2008-04-01

    In this paper, components of an industrial wastewater that cause operational problems during biological treatment were oxidized by UV light and hydrogen peroxide (UV/H202). Preoxidation of wastewater was shown to remove polyvinylpyrrolidone (PVP) and ethoxylate surfactant and increase overall biodegradability. Several UV intensities and hydrogen peroxide concentrations were tested to find optimal conditions for the complete depolymerization of PVP in a synthetic wastewater composed of high concentrations of hydroxyl radical scavengers. To compare treatment options, absorption isotherms for PVP on granular activated carbon (GAC) in water and in the synthetic phase-inversion wastewater matrix were determined. The data were extrapolated to estimate the cost of using UV/H2O2, GAC, or off-site treatment. It was found that UV/H2O2 pretreatment was economically viable. Incomplete oxidation of an ethoxylate surfactant increased foaming tendency and foam stability; however, extended oxidation (> 90 minutes) destroyed the foam.

  11. Biological insertion of nanostructured germanium and titanium oxides into diatom biosilica

    Science.gov (United States)

    Jeffryes, Clayton S.

    There is significant interest in titanium oxide and germanium-silicon oxide nanocomposites for optoelectronic, photocatalytic, and solar cell applications. The ability of the marine diatom Pinnularia sp. to uptake soluble metal oxides from cell culture medium, and incorporate them into the micro- and nano-structure of their amorphous silica cell walls, called frustules, was evaluated using an engineered photobioreactor system. The effects of metal oxides on the structural and elemental properties of the frustule were also evaluated. Diatom cell cultures grown in 5 L photobioreactors were initially charged with 0.5 mM of soluble silicon, Si(OH)4, an obligate substrate required for frustule fomation. Upon exhaustion of Si(OH)4 cells were exposed to the mixed pulse-addition of soluble silicon and germanium or co-perfusion addition of soluble silicon and titanium, which were incorporated into the frustules. Metals composition of the cell culture medium, diatom biomass and purified frustules were measured, as was the local elemental composition within the frustule pores and the metal oxide crystallinity. Diatom frustules having a germanium composition of 1.6 wt % were devoid of the native intra-pore structures and possessed enhanced photoluminescence and electroluminescence when compared to frustules without Ge. Diatoms cultivated in the presence of soluble titanium incorporated amorphous titania into the frustule, which maintained native structure even when local TiO2 concentrations within the nanopores approached 60 wt. %. Titanium oxide could also be biomimetically deposited directly within the diatom nanopores by adsorbing poly-L-lysine to the diatom biosilica where it catalyzed the soluble titanium precursor Ti-BALDH into amorphous titania nanoparticles. Both biogenic and biomimetic titania could be converted to anatase titanium by thermal annealing. It was determined that nanostructured metal oxide composites can be fabricated biomimetically or in cell culture to

  12. Photolytic degradation of sulfamethoxazole and trimethoprim using UV-A, UV-C and vacuum-UV (VUV).

    Science.gov (United States)

    Kim, Hyun Young; Kim, Tae-Hun; Yu, Seungho

    2015-01-01

    The photolytic degradation of the non-degradable pharmaceuticals sulfamethoxazole (SMX) and trimethoprim (TMP) in an aqueous solution was investigated using three kinds of low-pressure mercury lamp UV-A (352 nm), UV-C (254 nm), and vacuum-UV (VUV, 185 nm and 254 nm). The degradation rates were highly dependent on the target compounds as well as the UV sources. No degradation of the target compounds was observed using UV-A treatment, because there was no overlap between the UV-A emission spectrum and absorption spectrum of the target compounds. On the other hand, UVC and VUV revealed higher reactivity. The results also indicated that SMX had a greater potential to react photochemically than TMP. Among the UV sources, VUV was the most effective process for the degradation of target compounds. Furthermore, the addition of oxidants such as hydrogen peroxide (H2O2) and sodium persulfate (Na2S2O8) to the reaction system improved the overall degradation rate significantly.The experimental results for the VUV-irradiated samples with the addition of methanol as a hydroxyl radical scavenger revealed that hydroxyl radicals contribute significantly to the elimination of the target compound. Overall, the degradation rate of the target compounds was in the order: VUV = UV-C > UV-A for sulfamethoxazole and VUV/H2O2 > VUV/ Na2S2O8 > VUV >UV-C >UV-A for trimethoprim.

  13. Conductive diamond electrochemical oxidation of caffeine-intensified biologically treated urban wastewater.

    Science.gov (United States)

    Martín de Vidales, María J; Millán, María; Sáez, Cristina; Pérez, José F; Rodrigo, Manuel A; Cañizares, Pablo

    2015-10-01

    In this work, the usefulness of Conductive Diamond Electrochemical Oxidation (CDEO) to degrade caffeine in real urban wastewater matrixes was assessed. The oxidation of actual wastewater intensified with caffeine (from 1 to 100 mg L(-1)) was studied, paying particular attention to the influence of the initial load of caffeine and the differences observed during the treatment of caffeine in synthetic wastewater. The results showed that CDEO is a technology that is capable of efficiently degrading this compound even at very low concentrations and that it can even be completely depleted. Profiles of the ionic species of S (SO4(2-)), N (NH4(+), NO3(-)) and Cl (ClO(-), ClO3(-) and ClO4(-)) were monitored and explained for plausible oxidation mechanisms. It was observed that the efficiency achieved is higher in the treatment of real wastewater than in the oxidation of synthetic wastewater because of the contribution of electrogenerated oxidant species such as hypochlorite. The formation of chlorate and perchlorate during electrochemical processes was observed, and a combined strategy to prevent this important drawback was successfully tested based on the application of low current densities with the simultaneous dosing of hydrogen peroxide.

  14. A magnetic-dependent protein corona of tailor-made superparamagnetic iron oxides alters their biological behaviors

    Science.gov (United States)

    Liu, Ziyao; Zhan, Xiaohui; Yang, Minggang; Yang, Qi; Xu, Xianghui; Lan, Fang; Wu, Yao; Gu, Zhongwei

    2016-03-01

    In recent years, it is becoming increasingly evident that once nanoparticles come into contact with biological fluids, a protein corona surely forms and critically affects the biological behaviors of nanoparticles. Herein, we investigate whether the formation of protein corona on the surface of superparamagnetic iron oxides (SPIOs) is influenced by static magnetic field. Under static magnetic field, there is no obvious variation in the total amount of protein adsorption, but the proportion of adsorbed proteins significantly changes. Noticeably, certain proteins including apolipoproteins, complement system proteins and acute phase proteins, increase in the protein corona of SPIOs in the magnetic field. More importantly, the magnetic-dependent protein corona of SPIOs enhances the cellular uptake of SPIOs into the normal cell line (3T3 cells) and tumor cell line (HepG2 cells), due to increased adsorption of apolipoprotein. In addition, SPIOs with the magnetic-dependent protein corona cause high cytotoxicity to 3T3 cells and HepG2 cells. This work discloses that superparamagnetism as a key feature of SPIOs affects the composition of protein corona to a large extent, which further alters the biological behaviors of SPIOs.In recent years, it is becoming increasingly evident that once nanoparticles come into contact with biological fluids, a protein corona surely forms and critically affects the biological behaviors of nanoparticles. Herein, we investigate whether the formation of protein corona on the surface of superparamagnetic iron oxides (SPIOs) is influenced by static magnetic field. Under static magnetic field, there is no obvious variation in the total amount of protein adsorption, but the proportion of adsorbed proteins significantly changes. Noticeably, certain proteins including apolipoproteins, complement system proteins and acute phase proteins, increase in the protein corona of SPIOs in the magnetic field. More importantly, the magnetic-dependent protein

  15. CHLOROPHENOL DEGRADATION BY ELECTROCATALYSIS COMBINED WITH UV RADIATION%电催化与紫外光辐射降解氯酚

    Institute of Scientific and Technical Information of China (English)

    吴祖成; 叶倩; 周明华; 丛燕青

    2002-01-01

    @@ Chlorinated organic compounds, especially chlorophenols are well-known water priority pollutant family due to their toxicity and potential health hazard. As biological treatment processes for the degradation of chlorinated phenols have not been effective, various technologies and processes such as activated carbon adsorption[1], chemical oxidation[2], have been conventionally attempted for phenolic waster treatment. Recently, advanced oxidation processes (AOPs) have attracted a great deal of attention for treatment of phenolic wastewater, among these chemical oxidation ultraviolet (UV) oxidation system[3], anodic oxidation and indirect electro-oxidation have been widely studied[4]. Though a number of researchers worked on the degradation of chlorophenol by UV radiation or electrochemical processes, there are few reports on both methods for organic wastewater treatment. If these two processes can operate in harmony, the degradation efficiency would be enhanced.

  16. A predictive model of iron oxide nanoparticles flocculation tuning Z-potential in aqueous environment for biological application

    Energy Technology Data Exchange (ETDEWEB)

    Baldassarre, Francesca, E-mail: francesca.baldassarre@unisalento.it [University of Salento, Department of Cultural Heritage (Italy); Cacciola, Matteo, E-mail: matteo.cacciola@unirc.it [University “Mediterranea” of Reggio Calabria, DICEAM (Italy); Ciccarella, Giuseppe, E-mail: giuseppe.ciccarella@unisalento.it [University of Salento, Department of Innovation Engineering (Italy)

    2015-09-15

    Iron oxide nanoparticles are the most used magnetic nanoparticles in biomedical and biotechnological field because of their nontoxicity respect to the other metals. The investigation of iron oxide nanoparticles behaviour in aqueous environment is important for the biological applications in terms of polydispersity, mobility, cellular uptake and response to the external magnetic field. Iron oxide nanoparticles tend to agglomerate in aqueous solutions; thus, the stabilisation and aggregation could be modified tuning the colloids physical proprieties. Surfactants or polymers are often used to avoid agglomeration and increase nanoparticles stability. We have modelled and synthesised iron oxide nanoparticles through a co-precipitation method, in order to study the influence of surfactants and coatings on the aggregation state. Thus, we compared experimental results to simulation model data. The change of Z-potential and the clusters size were determined by Dynamic Light Scattering. We developed a suitable numerical model to predict the flocculation. The effects of Volume Mean Diameter and fractal dimension were explored in the model. We obtained the trend of these parameters tuning the Z-potential. These curves matched with the experimental results and confirmed the goodness of the model. Subsequently, we exploited the model to study the influence of nanoparticles aggregation and stability by Z-potential and external magnetic field. The highest Z-potential is reached up with a small external magnetic influence, a small aggregation and then a high suspension stability. Thus, we obtained a predictive model of Iron oxide nanoparticles flocculation that will be exploited for the nanoparticles engineering and experimental setup of bioassays.

  17. Schwertmannite and Fe oxides formed by biological low-pH Fe(II) oxidation versus abiotic neutralization: Impact on trace metal sequestration

    Science.gov (United States)

    Burgos, William D.; Borch, Thomas; Troyer, Lyndsay D.; Luan, Fubo; Larson, Lance N.; Brown, Juliana F.; Lambson, Janna; Shimizu, Masayuki

    2012-01-01

    Three low-pH coal mine drainage (CMD) sites in central Pennsylvania were studied to determine similarities in sediment composition, mineralogy, and morphology. Water from one site was used in discontinuous titration/neutralization experiments to produce Fe(III) minerals by abiotic oxidative hydrolysis for comparison with the field precipitates that were produced by biological low-pH Fe(II) oxidation. Even though the hydrology and concentration of dissolved metals of the CMD varied considerably between the three field sites, the mineralogy of the three iron mounds was very similar. Schwertmannite was the predominant mineral precipitated at low-pH (2.5-4.0) along with lesser amounts of goethite. Trace metals such as Zn, Ni and Co were only detected at μmol/g concentrations in the field sediments, and no metals (other than Fe) were removed from the CMD at any of the field sites. Metal cations were not lost from solution in the field because of unfavorable electrostatic attraction to the iron mound minerals. Ferrihydrite was the predominant mineral formed by abiotic neutralization (pH 4.4-8.4, 4 d aging) with lesser amounts of schwertmannite and goethite. In contrast to low-pH precipitation, substantial metal removal occurred in the neutralized CMD. Al was likely removed as hydrobasaluminite and Al(OH) 3, and as a co-precipitate into schwertmannite or ferrihydrite. Zn, Ni and Co were likely removed via adsorption onto and co-precipitation into the freshly formed Fe and Al solids. Mn was likely removed by co-precipitation and, at the highest final pH values, as a Mn oxide. Biological low-pH Fe(II) oxidation can be cost-effectively used to pre-treat CMD and remove Fe and acidity prior to conventional neutralization techniques. A further benefit is that solids formed under these conditions may be of industrial value because they do not contain trace metal or metalloid contaminants.

  18. High rates of denitrification and nitrous oxide emission in arid biological soil crusts from the Sultanate of Oman

    DEFF Research Database (Denmark)

    Abed, Raeid M M; Lam, Phyllis; De Beer, Dirk;

    2013-01-01

    Using a combination of process rate determination, microsensor profiling and molecular techniques, we demonstrated that denitrification, and not anaerobic ammonium oxidation (anammox), is the major nitrogen loss process in biological soil crusts from Oman. Potential denitrification rates were 584...... that nitrogen loss via denitrification is a dominant process in crusts from Oman, which leads to N 2 O gas emission and potentially reduces desert soil fertility. © 2013 International Society for Microbial Ecology.......Using a combination of process rate determination, microsensor profiling and molecular techniques, we demonstrated that denitrification, and not anaerobic ammonium oxidation (anammox), is the major nitrogen loss process in biological soil crusts from Oman. Potential denitrification rates were 584....... Strikingly, N 2 O gas was emitted at very high potential rates of 387±143 and 31±6 μmol N m -2 h -1 from the cyanobacterial and lichen crust, respectively, with N 2 O accounting for 53-66% of the total emission of nitrogenous gases. Microsensor measurements revealed that N 2 O was produced in the anoxic...

  19. Assessing the application of advanced oxidation processes, and their combination with biological treatment, to effluents from pulp and paper industry.

    Science.gov (United States)

    Merayo, Noemí; Hermosilla, Daphne; Blanco, Laura; Cortijo, Luis; Blanco, Angeles

    2013-11-15

    The closure of water circuits within pulp and paper mills has resulted in a higher contamination load of the final mill effluent, which must consequently be further treated in many cases to meet the standards imposed by the legislation in force. Different treatment strategies based on advanced oxidation processes (ozonation and TiO2-photocatalysis), and their combination with biological treatment (MBR), are herein assessed for effluents of a recycled paper mill and a kraft pulp mill. Ozone treatment achieved the highest efficiency of all. The consumption of 2.4 g O3 L(-1) resulted in about a 60% COD reduction treating the effluent from the kraft pulp mill at an initial pH=7; although it only reached about a 35% COD removal for the effluent of the recycled paper mill. Otherwise, photocatalysis achieved about a 20-30% reduction of the COD for both type of effluents. In addition, the effluent from the recycled paper mill showed a higher biodegradability, so combinations of these AOPs with biological treatment were tested. As a result, photocatalysis did not report any significant COD reduction improvement whether being performed as pre- or post-treatment of the biological process; whereas the use of ozonation as post-biological treatment enhanced COD removal a further 10%, summing up a total 90% reduction of the COD for the combined treatment, as well as it also supposed an increase of the presence of volatile fatty acids, which might ultimately enable the resultant wastewater to be recirculated back to further biological treatment.

  20. Omega-3 fatty acid fish oil dietary supplements contain saturated fats and oxidized lipids that may interfere with their intended biological benefits.

    Science.gov (United States)

    Mason, R Preston; Sherratt, Samuel C R

    2017-01-29

    Widely available fish oil dietary supplements (DS) may contain fats and oxidized lipids in addition to the beneficial omega-3 fatty acids (OM3FAs) for which they are purchased. Little is known about the potential biological effects of these oxidized lipids. The objective of this study was to assess the fatty acid content, oxidation products, and biological effects of leading fish oil DS available in the United States. Three top-selling fish oil DS in the US were included in this analysis. Fatty acid composition was measured using gas chromatography. Lipid oxidation (primary and secondary products) was measured by spectroscopy in both DS and a prescription OM3FA product. OM3FAs were also isolated and concentrated from DS and were tested for the ability to inhibit copper-induced oxidation of human small dense low-density lipoprotein particles (sdLDL) in vitro. Fish oil DS were found to contain more than 30 different fatty acids, including 10 to 14 different saturated species comprising up to 36% of the total fatty acid content. Levels of OM3FAs also varied widely among DS (33%-79%). Primary (peroxide), secondary (anisidine), and total oxidation products exceeded maximum levels established by international standards of quality in the DS but not the prescription OM3FA product. Oxidation of sdLDL was inhibited by >95% (P saturated fat and oxidized OM3FAs found in common DS may interfere with their intended/potential biological benefits.

  1. Neutrophilic Iron Oxidizing Bacteria: Occurrence and Relevance in Biological Drinking Water Treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen;

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully ...

  2. Neutrophilic iron-oxidizing bacteria: occurrence and relevance in biological drinking water treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen;

    2013-01-01

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully ...

  3. Formation and colloidal behaviour of elemental sulphur produced from the biological oxidation of hydrogensulphide.

    NARCIS (Netherlands)

    Janssen, A.J.H.

    1996-01-01

    The formation and aggregation of elemental sulphur from the microbiological oxidation of hydrogensulphide (H 2 S) by a mixed population of aerobic Thiobacillus -like bacteria has been investigated. Sulphide is formed during the anaerobic treatment of wastewaters whi

  4. Kinetic Constants for Biological Ammonium and Nitrite Oxidation Processes Under Sulfide Inhibition.

    Science.gov (United States)

    Bejarano-Ortiz, Diego Iván; Huerta-Ochoa, Sergio; Thalasso, Frédéric; Cuervo-López, Flor de María; Texier, Anne-Claire

    2015-12-01

    Inhibition of nitrification by sulfide was assessed using sludge obtained from a steady-state nitrifying reactor. Independent batch activity assays were performed with ammonium and nitrite as substrate, in order to discriminate the effect of sulfide on ammonium and nitrite oxidation. In the absence of sulfide, substrate affinity constants (K S,NH4  = 2.41 ± 0.11 mg N/L; K s, NO2  = 0.74 ± 0.03 mg N/L) and maximum specific rates (q max,NH4  = 0.086 ± 0.008 mg N/mg microbial protein h; q max,NO2  = 0.124 ± 0.001 mg N/mg microbial protein h) were determined. Inhibition of ammonium oxidation was no-competitive (inhibition constant (K i , NH4 ) of 2.54 ± 0.12 mg HS(-)-S/L) while inhibition of nitrite oxidation was mixed (competitive inhibition constant (K' i , NO2 ) of 0.22 ± 0.03 mg HS(-)-S/L and no-competitive inhibition constant (K i , NO2 ) of 1.03 ± 0.06 mg HS(-)-S/L). Sulfide has greater inhibitory effect on nitrite oxidation than ammonium oxidation, and its presence in nitrification systems should be avoided to prevent accumulation of nitrite. By simulating the effect of sulfide addition in a continuous nitrifying reactor under steady-state operation, it was shown that the maximum sulfide concentration that the sludge can tolerate without affecting the ammonium consumption efficiency and nitrate yield is 1 mg HS(-)-S/L.

  5. Improved treatment approach for the removal of aromatic compounds using polymeric beads in Fenton pretreatment and biological oxidation.

    Science.gov (United States)

    Ramteke, Lokeshkumar P; Gogate, Parag R

    2016-10-01

    An improved approach based on the use of iron-doped polymeric beads (IPB) as Fenton catalyst in the pretreatment and biomass-doped polymeric bead (BPB) in the biological oxidation has been reported for the removal of different aromatic mixtures present as pollutants in the aqueous solutions. Degradation has been investigated at fixed loading of IPB as 2.5 % weight basis and varying loading of hydrogen peroxide so as to understand the effect of oxidant loading on the extent of degradation. It has been observed that the maximum removal efficiency as 75.5, 81.4, and 59.1 % was obtained for the benzene-toluene-naphthalene-xylene (BTNX), benzene-toluene-ethylbenzene-xylene (BTEX), and benzene-toluene-naphthalene-p-nitrophenol (BTNp-NP) mixtures, respectively, at a 40-min pretreatment and optimum pH of 3.5. The biodegradability index was also observed in the favorable range of 0.4 to 0.5 after the pretreatment at optimum H2O2 loading of 1.5 g L(-1). Maximum COD removal efficiency of 99.2, 99.3, and 99.6 % was obtained using the biological oxidation treatment for 40 h for the case of BTNX, BTEX, and BTNp-NP mixtures, respectively. Analysis of kinetic models revealed that degradation followed three distinct stages based on fitting of the three-stage model and BPB was found to be more efficient as compared to the primary activated sludge (PAS) and modified activated sludge (MAS). Reusability studies confirmed that both IPB and BPB were effective over many cycles giving stable performance during degradation without leaching of Fe(3+) ions into the solution.

  6. Design and preliminary test of a fluidised bed photoreactor for ethylene oxidation on mesoporous mixed SiO2/TiO2 nanocomposites under UV-A illumination

    Directory of Open Access Journals (Sweden)

    Maria Lucia V. de Chiara

    2014-12-01

    Full Text Available Ethylene (C2H4 is a plant hormone that has numerous effects on many horticultural and ornamental crops. It accelerates senescence, stimulates chlorophyll loss, enhances excessive softening, promotes discoloration and browning during storage of fresh produce. Among the techniques used to remove or inhibit ethylene action during postharvest handling of fresh products (potassium-based system, high temperature catalytic oxidation, inhibition of ethylene receptors, the use of titanium oxide (TiO2-based materials with photocatalytic activity under ultraviolet (UV light is one of the most promising. A fluidised-bed photoreactor (FBP was designed to decompose ethylene in the storage room atmosphere, and the relative prototype was manufactured. Since TiO2 powder alone is not suitable for use within a fluidised bed, preliminary tests to select the best support were performed. Alumina microspheres showed a good fluidisation behavior; its functionality was tested with different kind of support material and actual photocatalytic activity was tested using SiO2/TiO2-coated alumina microspheres. A reduction of approximately 72% of ethylene concentration in the tested 40 ppm ethylene gas mixture was observed after 4.5 h of 36W UV light exposure. FBP resulted to be suitable to avoid the detrimental presence of C2H4 in the atmosphere surrounding fresh products within cold storage rooms.

  7. Simultaneous investigation of sesquiterpenes, pyrrolizidine alkaloids and N-oxides in Butterbur (Petasites hybridus) with an offline 2D-combination of HPLC-UV and LC-MMI-ToF-MS.

    Science.gov (United States)

    Aydın, Ahmet Alper; Letzel, Thomas

    2013-11-01

    With the worldwide rapid increasing interest in the use of natural products as dietary supplements, medical remedies and functional foods, it has been accepted that omitting the plant constituents with potential adverse effects was a huge fault of the past. Several countries developed regulations to limit the consumption of such products in the markets. Among these natural products, butterbur (Petasites) has been used for years as herbal supplement for its anti-spasmodic and anti-inflammatory effects. However, its hepatotoxic alkaloid content limits the direct usage. In this study, investigation of sesquiterpenes and pyrrolizidine alkaloids (PAs) together with their N-oxide forms has been conducted with an offline 2D-combination using high-performance liquid chromatography with UV detection (HPLC-UV) and liquid chromatography - multi mode ionization - time-of-flight mass spectrometry (LC-MMI-ToF-MS) for plant screening. The content has been qualitatively investigated to provide information on the constituents of the plant rhizomes extracted using ethanol. Besides the reported hepatotoxic and medically bio-active plant constituents, a strategy has been suggested for estimating the retention order and retention times with respect to calculated logD (distribution coefficient) and hydrophobicity distributions on C18 reversed-phase column when all standard compounds are not available in laboratory. In this sense, the influence of calculated logD and hydrophobicity distributions on retention time has been clarified via available PA and PA-N-oxide standards. The ethanolic extract of Petasites hybridus has been used for examination of the strategy in a real-sample model. Additionally, the advantages of the developed HPLC-UV and LC-MMI-ToF-MS combination have been discussed with respect to the presented results.

  8. Nitrous oxide determination in postmortem biological samples: a case of serial fatal poisoning in a public hospital.

    Science.gov (United States)

    Poli, Diana; Gagliano-Candela, Roberto; Strisciullo, Giuseppe; Colucci, Anna P; Strada, Luigi; Laviola, Domenica; Goldoni, Matteo; Mutti, Antonio

    2010-01-01

    In a public hospital, eight cases of fatal poisoning by nitrous oxide (N(2)O) occurred under oxygen administration, due to an erroneous swapping of the lines in the gas system. The aim of the study was to clarify the factors involved in asphyxia by characterizing gases from different lines and measuring N(2)O concentrations in postmortem biological samples from bodies exhumed. Analyses carried out on the gas system confirmed the erroneous substitution of O(2) line with N(2)O and air line with O(2). Consequently, high N(2)O amounts were revealed in several tissues and gaseous biological samples. All specimens were analyzed by headspace gas chromatography technique. A rigorous quantitative analysis was possible only in blood (11.29-2152.04 mg/L) and urine (95.11 mg/L) and in air samples from stomach and trachea (from 5.28 to 83.63 g/m(3)). This study demonstrates that N(2)O can be detected in biological samples even 1 month after death.

  9. A magnetic-dependent protein corona of tailor-made superparamagnetic iron oxides alters their biological behaviors.

    Science.gov (United States)

    Liu, Ziyao; Zhan, Xiaohui; Yang, Minggang; Yang, Qi; Xu, Xianghui; Lan, Fang; Wu, Yao; Gu, Zhongwei

    2016-04-14

    In recent years, it is becoming increasingly evident that once nanoparticles come into contact with biological fluids, a protein corona surely forms and critically affects the biological behaviors of nanoparticles. Herein, we investigate whether the formation of protein corona on the surface of superparamagnetic iron oxides (SPIOs) is influenced by static magnetic field. Under static magnetic field, there is no obvious variation in the total amount of protein adsorption, but the proportion of adsorbed proteins significantly changes. Noticeably, certain proteins including apolipoproteins, complement system proteins and acute phase proteins, increase in the protein corona of SPIOs in the magnetic field. More importantly, the magnetic-dependent protein corona of SPIOs enhances the cellular uptake of SPIOs into the normal cell line (3T3 cells) and tumor cell line (HepG2 cells), due to increased adsorption of apolipoprotein. In addition, SPIOs with the magnetic-dependent protein corona cause high cytotoxicity to 3T3 cells and HepG2 cells. This work discloses that superparamagnetism as a key feature of SPIOs affects the composition of protein corona to a large extent, which further alters the biological behaviors of SPIOs.

  10. Toxicity assessment of textile effluents treated by advanced oxidative process (UV/TiO2 and UV/TiO2/H2O2) in the species Artemia salina L.

    Science.gov (United States)

    Garcia, Juliana Carla; de Souza Freitas, Thábata Karoliny Formicoly; Palácio, Soraya Moreno; Ambrósio, Elizangela; Souza, Maísa Tatiane Ferreira; Santos, Lídia Brizola; de Cinque Almeida, Vitor; de Souza, Nilson Evelázio

    2013-03-01

    Textile industry wastes raise a great concern due to their strong coloration and toxicity. The objective of the present work was to characterize the degradation and mineralization of textile effluents by advanced oxidative processes using either TiO(2) or TiO(2)/H(2)O(2) and to monitor the toxicity of the products formed during 6-h irradiation in relation to that of the in natura effluent. The results demonstrated that the TiO(2)/H(2)O(2) association was more efficient in the mineralization of textile effluents than TiO(2), with high mineralized ion concentrations (NH (4) (+) , NO (3) (-) , and SO (4) (2-) ) and significantly decreased organic matter ratios (represented by the chemical oxygen demand and total organic carbon). The toxicity of the degradation products after 4-h irradiation to Artemia salina L. was not significant (below 10 %). However, the TiO(2)/H(2)O(2) association produced more toxicity under irradiation than the TiO(2) system, which was attributed to the increased presence of oxidants in the first group. Comparatively, the photogenerated products of both TiO(2) and the TiO(2)/H(2)O(2) association were less toxic than the in natura effluent.

  11. Simultaneous degradation of disinfection byproducts and earthy-musty odorants by the UV/H2O2 advanced oxidation process.

    Science.gov (United States)

    Jo, Chang Hyun; Dietrich, Andrea M; Tanko, James M

    2011-04-01

    Advanced treatment technologies that control multiple contaminants are beneficial to drinking water treatment. This research applied UV/H(2)O(2) for the simultaneous degradation of geosmin, 2-methylisoborneol, four trihalomethanes and six haloacetic acids. Experiments were conducted in de-ionized water at 24 ± 1.0 °C with ng/L amounts of odorants and μg/L amounts of disinfection byproducts. UV was applied with and without 6 mg/L H(2)O(2.) The results demonstrated that brominated trihalomethanes and brominated haloacetic acids were degraded to a greater extent than geosmin and 2-methylisoborneol. Tribromomethane and dibromochloromethane were degraded by 99% and 80% respectively at the UV dose of 1200 mJ/cm(2) with 6 mg/L H(2)O(2), whereas 90% of the geosmin and 60% of the 2-methylisoborneol were removed. Tribromoacetic acid and dibromoacetic acid were degraded by 99% and 80% respectively under the same conditions. Concentrations of trichloromethane and chlorinated haloacetic acids were not substantially reduced under these conditions and were not effectively removed at doses designed to remove geosmin and 2-methylisoborneol. Brominated compounds were degraded primarily by direct photolysis and cleavage of the C-Br bond with pseudo first order rate constants ranging from 10(-3) to 10(-2) s(-1). Geosmin and 2-methylisoborneol were primarily degraded by reaction with hydroxyl radical with direct photolysis as a minor factor. Perchlorinated disinfection byproducts were degraded by reaction with hydroxyl radicals. These results indicate that the UV/H(2)O(2) can be applied to effectively control both odorants and brominated disinfection byproducts.

  12. Synthesis of few-layered, high-purity graphene oxide sheets from different graphite sources for biology

    Science.gov (United States)

    Jasim, Dhifaf A.; Lozano, Neus; Kostarelos, Kostas

    2016-03-01

    This work aimed to interrogate the role that the starting graphitic material played on the physicochemical properties of graphene oxide (GO) sheets and their impact on mammalian cell viability following exposure to those flakes. Three different GO thin sheets were synthesised from three starting graphite material: flakes (GO-f), ground (GO-g) and powder (GO-p) using a modified Hummers’ method. The synthetic yield of this methodology was found to differ according to type of starting material, with GO-p resulting in most efficient yields. Structural and morphological comparison of the three GO sheet types were carried out using transmission electron microscopy and atomic force microscopy. Optical properties were measured using UV/visible and fluorescence spectroscopy. Surface characteristics and chemistry were determined using a battery of techniques. Exposure to human cells was studied using the human A549 lung epithelial cultures. Our results revealed that all three GO samples were composed of few-layer sheets with similar physicochemical and surface characteristics. However, significant differences were observed in terms of their lateral dimensions with GO-p, prepared from graphite powder, being the largest among the GOs. No cytotoxicity was detected for any of the GO samples following exposure onto A549 cells up to 48 h. In conclusion, the form and type of the starting graphite material is shown to be an important factor that can determine the synthetic yield and the structural characteristics of the resulting GO sheets.

  13. Synthesis and biological evaluation of nitric oxide-donating analogues of sulindac for prostate cancer treatment.

    Science.gov (United States)

    Nortcliffe, Andrew; Ekstrom, Alexander G; Black, James R; Ross, James A; Habib, Fouad K; Botting, Nigel P; O'Hagan, David

    2014-01-15

    A series of analogues of the non-steroidal anti-inflammatory drug (NSAID) sulindac 1 were synthesised tethered to nitric oxide (NO) donating functional groups. Sulindac shows antiproliterative effects against immortal PC3 cell lines. It was previously demonstrated that the effect can be enhanced when tethered to NO releasing groups such as nitrate esters, furoxans and sydnonimines. To explore this approach further, a total of fifty-six sulindac-NO analogues were prepared and they were evaluated as NO-releasing cytotoxic agents against prostate cancer (PCa) cell lines. Compounds 1k and 1n exhibited significant cytotoxic with IC50 values of 6.1±4.1 and 12.1±3.2μM, respectively, coupled with observed nitric oxide release.

  14. Biologically Inspired Design of Biocompatible Iron Oxide Nanoparticles for Biomedical Applications

    OpenAIRE

    Demirer, Gözde S.; Okur, Aysu C; Kızılel, Seda

    2015-01-01

    During the last couple of decades considerable research efforts have been directed towards the synthesis and coating of iron oxide nanoparticles (IONPs) for biomedical applications. To address the current limitations, recent studies have focused on the design of new generation nanoparticle systems whose internalization and targeting capabilities have been improved through surface modifications. This review covers the most recent challenges and advances in the development of IONPs with enhance...

  15. The biological basis of autism spectrum disorders: evaluation of oxidative stress and erytrocyte membrane alterations

    OpenAIRE

    Ghezzo, Alessandro

    2015-01-01

    This case-control study involved a total of 29 autistic children (Au) aged 6 to 12 years, and 28 gender and age-matched typically developing children (TD). We evaluated a high number of peripheral oxidative stress parameters, erythrocyte and lymphocyte membrane functional features and membrane lipid composition of erythrocyte. Erythrocyte TBARS, Peroxiredoxin II, Protein Carbonyl Groups and urinary HEL and isoprostane levels were elevated in AU (confirming an imbalance of the redox status of...

  16. Biological activity of some naturally occurring resins, gums and pigments against in vitro LDL oxidation.

    Science.gov (United States)

    Andrikopoulos, Nikolaos K; Kaliora, Andriana C; Assimopoulou, Andreana N; Papapeorgiou, Vassilios P

    2003-05-01

    Naturally occurring gums and resins with beneficial pharmaceutical and nutraceutical properties were tested for their possible protective effect against copper-induced LDL oxidation in vitro. Chiosmastic gum (CMG) (Pistacia lentiscus var. Chia resin) was the most effective in protecting human LDL from oxidation. The minimum and maximum doses for the saturation phenomena of inhibition of LDL oxidation were 2.5 mg and 50 mg CMG (75.3% and 99.9%, respectively). The methanol/water extract of CMG was the most effective compared with other solvent combinations. CMG when fractionated in order to determine a structure-activity relationship showed that the total mastic essential oil, collofonium-like residue and acidic fractions of CMG exhibited a high protective activity ranging from 65.0% to 77.8%. The other natural gums and resins (CMG resin 'liquid collection', P. terebinthus var. Chia resin, dammar resin, acacia gum, tragacanth gum, storax gum) also tested as above, showed 27.0%-78.8% of the maximum LDL protection. The other naturally occurring substances, i.e. triterpenes (amyrin, oleanolic acid, ursolic acid, lupeol, 18-a-glycyrrhetinic acid) and hydroxynaphthoquinones (naphthazarin, shikonin and alkannin) showed 53.5%-78.8% and 27.0%-64.1% LDL protective activity, respectively. The combination effects (68.7%-76.2% LDL protection) of ursolic-, oleanolic- and ursodeoxycholic- acids were almost equal to the effect (75.3%) of the CMG extract in comparable doses.

  17. Biological Effects of Short, High-Level Exposure to Gases: Nitrogen Oxides.

    Science.gov (United States)

    1980-07-01

    SUPPLEMENTARY NOT ES3 This project was one of four under the same contract; the others covered ammonia , carbon monoxide, and sulfur dioxide. 3 IS. KEY wOROS...characterize the biological responses to short, high-level exposures to four gases associated with certain Army weapons systems ( ammonia , carbon monoxide...20- i --- 7 (2) Biochemical and Other Effects Buckley and BalchumlO found biochemical changes, principally in enzyme activity of the liver, spleen

  18. Fabrication of ciprofloxacin molecular imprinted polymer coating on a stainless steel wire as a selective solid-phase microextraction fiber for sensitive determination of fluoroquinolones in biological fluids and tablet formulation using HPLC-UV detection.

    Science.gov (United States)

    Mirzajani, Roya; Kardani, Fatemeh

    2016-04-15

    A molecularly imprinted polymer (MIP) fiber on stainless steel wire using ciprofloxacin template with a mild template removal condition was synthetized and evaluated for fiber solid phase microextraction (SPME) of fluoroquinolones (FQs) from biological fluids and pharmaceutical samples, followed by high performance liquid chromatography analysis with UV detection (HPLC-UV). The developed MIP fiber exhibited high selectivity for the analytes in complex matrices. The coating of the fibers were inspected using fourier transform infrared spectrophotometry, thermogaravimetric analysis, energy dispersive X-ray (EDX) spectroscopy as well as by scanning electron microscopy (SEM). The fiber shows high thermal stability (up to 300°C), good reproducibility and long lifetime. The composite coating did not swell in organic solvents nor did it strip off from the substrate. It was also highly stable and extremely adherent to the surface of the stainless steel fiber. The fabricated fiber exclusively exhibited excellent extraction efficiency and selectivity for some FQs. The effective parameters influencing the microextraction efficiency such as pH, extraction time, desorption condition, and stirring rate were investigated. Under optimized conditions, the limits of detection of the four FQs ranged from 0.023-0.033 μg L(-1) (S/N=5) and the calibration graphs were linear in the concentration range from 0.1-40 μg L(-1), the inter-day and intraday relative standard deviations (RSD) for various FQs at three different concentration level (n=5) using a single fiber were 1.1-4.4% and the fiber to fiber RSD% (n=5) was 4.3-6.7% at 5 μg L(-1) of each anlyetes. The method was successfully applied for quantification of FQs in real samples including serum, plasma and tablet formulation with the recoveries between 97 to 102%.

  19. Scenarios of future UV radiation; Szenarien zukuenftiger UV-Strahlung

    Energy Technology Data Exchange (ETDEWEB)

    Reuder, J.; Koepke, P. [Muenchen Univ. (Germany). Meteorologisches Inst.; Dameris, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1999-07-01

    The purpose of the present study was to examine possible effects of the UV radiation field in terms of a biologically relevant quantity, namely erythema-weighted global irradiation intensity. This was done on the basis measured data and model simulations of total ozone content assuming different emission scenarios. Three ozone scenarios were analysed for the period from 2015 to 2050, one optimistic, one pessimistic and one currently considered to be realistic. The results show that a continuation of the past unrestrained increase in UV radiation appears unlikely. This is undoubtedly a success of current international political agreements for the protection of the ozone layer. However, one also has to consider that scenarios on the future production and emission of substances with an ozone depleting or global warming potential are subject to uncertainty. According to the supposedly realistic scenario UV radiation levels in the summer and autumn of 2050 will be back to the levels that prevailed around 1970, when atmospheric ozone concentrations were still largely undisturbed by man. By contrast, in winter and spring UV levels will continue at the high levels of recent years for several decades to come. If in addition volcanic eruptions occur, this will drastically alter stratospheric aerosol and ozone concentrations, thus probably causing an marked additional increase in UV radiation over a period of months. [German] Auf der Basis von Messwerten und von Modellsimulationen des Gesamtozongehaltes, unter der Annahme verschiedener Emissionsszenarien halogenierter Kohlenwasserstoffe, wurden moegliche Auswirkungen auf das UV-Strahlungsfeld anhand der biologisch relevanten Groesse der erythemgewichteten Globalbestrahlungsstaerke untersucht. Fuer die Jahre 2015 und 2050 wurden dazu jeweils 3 Ozonszenarien analysiert, die (nach derzeitiger Einschaetzung) wahrscheinliche, pessimistische und optimistische Bedingungen wiedergeben. Die Ergebnisse zeigen, dass eine ungebremste

  20. Bioaugmentation of biological contact oxidation reactor (BCOR) with phenol-degrading bacteria for coal gasification wastewater (CGW) treatment.

    Science.gov (United States)

    Fang, Fang; Han, Hongjun; Zhao, Qian; Xu, Chunyan; Zhang, Linghan

    2013-12-01

    This study was conducted to evaluate the performance of the biological contact oxidation reactor (BCOR) treating coal gasification wastewater (CGW) after augmented with phenol degrading bacteria (PDB). The PDB were isolated with phenol, 4-methyl phenol, 3,5-dimethyl phenol and resorcinol as carbon resources. Much of the refractory phenolic compounds were converted into easily-biodegradable compounds in spite of low TOC removal. The bioaugmentation with PDB significantly enhanced the removal of COD, total phenols (TP) and NH3-N, with efficiencies from 58% to 78%, 66% to 80%, and 5% to 25%, respectively. In addition, the augmented BCOR exhibited strong recovery capability in TP and COD removal while recovery of NH3-N removal needed longer time. Microbial community analysis revealed that the PDB presented as dominant populations in the bacteria consortia, which in turn determined the overall performance of the system.

  1. Biological Properties of Iron Oxide Nanoparticles for Cellular and Molecular Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Claus-Christian Glüer

    2010-12-01

    Full Text Available Superparamagnetic iron-oxide particles (SPIO are used in different ways as contrast agents for magnetic resonance imaging (MRI: Particles with high nonspecific uptake are required for unspecific labeling of phagocytic cells whereas those that target specific molecules need to have very low unspecific cellular uptake. We compared iron-oxide particles with different core materials (magnetite, maghemite, different coatings (none, dextran, carboxydextran, polystyrene and different hydrodynamic diameters (20–850 nm for internalization kinetics, release of internalized particles, toxicity, localization of particles and ability to generate contrast in MRI. Particle uptake was investigated with U118 glioma cells und human umbilical vein endothelial cells (HUVEC, which exhibit different phagocytic properties. In both cell types, the contrast agents Resovist, B102, non-coated Fe3O4 particles and microspheres were better internalized than dextran-coated Nanomag particles. SPIO uptake into the cells increased with particle/iron concentrations. Maximum intracellular accumulation of iron particles was observed between 24 h to 36 h of exposure. Most particles were retained in the cells for at least two weeks, were deeply internalized, and only few remained adsorbed at the cell surface. Internalized particles clustered in the cytosol of the cells. Furthermore, all particles showed a low toxicity. By MRI, monolayers consisting of 5000 Resovist-labeled cells could easily be visualized. Thus, for unspecific cell labeling, Resovist and microspheres show the highest potential, whereas Nanomag particles are promising contrast agents for target-specific labeling.

  2. Effect of Return Sludge Pre-concentration on Biological Phosphorus Removal in a Novel Oxidation Ditch

    Institute of Scientific and Technical Information of China (English)

    刘巍; 扬殿海; 徐立; 贾川; 卢文建; BOSIRE Omosa Isaiah; 沈昌明

    2012-01-01

    A pilot-scale,pre-anoxic-anaerobic oxidation ditch was used in this study to treat municipal wastewater with limited carbon source.A novel return activated sludge(RAS) pre-concentration tank was adopted for improv-ing the phosphorus removal efficiency and the effects of RAS pre-concentration ratio were studied.Under the opti-mal operational condition,the suspended total phosphorus(STP) and the total phosphorus(TP) removal efficiencies were around 58.9% and 63.9% respectively and the effluent-P was lower than 0.8 mg·L-1.The reason is that with the optimal RAS pre-concentration ratio,nitrate is completely removed with endogenous carbon source and the secondary phosphorus release is strictly restrained in the pre-anoxic tank.Therefore,the anaerobic phosphorus release and the carbon source uptake by phosphorus accumulation organisms(PAOs) in the sludge,which are ex-tremely important to the phosphorus removal process,can be fully satisfied.Furthermore,the oxidation-reduction potential is proved to be suitable for controlling the RAS pre-concentration ratio due to influent fluctuation and varied conditions.The novel modified system is also beneficial for PAO accumulation.

  3. Advanced oxidation technologies H{sub 2}O{sub 2}/UV evaluation in the treatment of effluent containing VCH (Vinylcyclohexene); Avaliacao do processo oxidativo avancado H{sub 2}O{sub 2}/UV no tratamento de efluente contendo VCH (Vinilciclohexeno)

    Energy Technology Data Exchange (ETDEWEB)

    Lenise, V.F.G.; Dezotti, M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Quimica; Aquino Neto, F.R. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica

    2004-07-01

    The study of vinylcyclohexene (VCH) degradation by the advanced oxidation technology H{sub 2}O{sub 2} /UV was researched in a pilot plant containing two Germetec, PFR reactors, with 0.7 L of useful volume. VCH is a persistent organic compound generated by thermal dimerization of 1,3-butadiene. One of the reactors had a warming/colding jacket and a low-pressure mercury vapor lamp, germicidal, of 25 W and the another had a medium-pressure mercury vapor lamp of 1.7 KW. Synthetic effluents containing VCH, VCH and ethanol and real hydroxyl terminated polybutadiene (HTPB) effluent were researched under different temperature and pH conditions. The aqueous effluent generated in HTPB plant was composed by 10-100 mg/L of VCH, others organic compounds like ethanol, butadiene and polymer, acidic pH, residual peroxide and a mean content of soluble organic carbon of 25000 mg/L. After 30 minutes of H{sub 2}O{sub 2}/UV treatment with a germicidal lamp , VCH was completely degradated while in the reactor with a medium pressure lamp after 5 minutes the complete VCH degradation happened. The degradation of others organic compounds in the effluent was observed with soluble organic carbon content reduction about 80%. The Kinetics of VCH degradation was monitored by GC/MS. (author)

  4. UV/H2 O2高级氧化工艺对水中布洛芬的去除试验%Test of Ibuprofen Removal in Water by Advanced Oxidation Process of UV/H2 O2

    Institute of Scientific and Technical Information of China (English)

    袁芳

    2015-01-01

    In UV/ H2 O2 process,effects of H 2 O2 concentration and water quality parameters on degradation of ibuprofen (IBU)were investigated. Furthermore,changes of IBU degradation,TOC removal and toxicity were studied,and photoproducts of IBU were also analyzed. Toxicity of IBU and its reaction samples were evaluated by bioluminescence inhibition using vibrio fischeri,and EC 50,15 min value of IBU was 68 mg / L. In UV direct photolysis,biological toxicity increased gradually with the degradation of IBU,while TOC had no change. when UV fluence was 3 816 mJ / cm2 ,41% of IBU was degraded,and the inhibition rate increased from 17. 48% to 43. 58% . In UV/ H2 O2 advanced processes,both toxicity and TOC were decreased with the degradation of IBU. When UV fluence was 7 632 mJ / cm2 ,all of IBU degraded,and the inhibition rate decreased from 18. 20% to 0. 8%,while TOC only began to decrease. Several photoproducts such as terephthalic acid,malonic acid,propionic acid,benzoic acid,glycerol and other small molecular carboxylic acid forming in this process were identified by GC MS. In UV/ H2 O2 processes,detoxification was much easier than mineralization,and the optimal time for degradation of pollutants in UV/ H 2 O2 process would be determined by parent compound degradation and toxicity changes.%考察了 UV/ H2 O2体系中,H2 O2投加量、水质参数对布洛芬(IBU)降解的影响。同时研究了该体系中,IBU降解、TOC去除及物质生物毒性三者的变化,并分析了降解产物的生成情况。结果表明 IBU 对 T3发光杆菌有较大的抑制发光作用, EC50,15 min为68 mg / L。UV直接光解,随着 IBU的降解,物质生物毒性逐渐增大,而 TOC 无变化。当紫外剂量达到3816 mJ /cm2时,IBU降解41%,反应液对发光菌的发光抑制率由17.48%升至43.58%。随着 IBU的降解,物质生物毒性和 TOC均逐渐减小。当紫外剂量达到7632 mJ / cm2时,IBU 全部降解,TOC 开始下降,

  5. Scientific Opinion on the substantiation of a health claim related to a combination of lycopene, vitamin E, lutein and selenium and protection of the skin from UV-induced (including photo-oxidative damage pursuant to Article 13(5 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2012-09-01

    Full Text Available

    Following an application from Nutrilinks Sarl, submitted pursuant to Article 13(5 of Regulation (EC No 1924/2006 via the Competent Authority of Cyprus, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to a combination of lycopene, vitamin E, lutein and selenium and protection of the skin from UV-induced (including photo-oxidative damage. The Panel considers that the combination of lycopene, vitamin E, lutein and selenium is sufficiently characterised. The claimed effect refers to the photo-protective activity of the food, delaying the appearance of UV-induced erythema and decreasing its intensity. The target population proposed by the applicant is healthy adults in the general population, and in particular people with sensitive skin. The Panel considers that protection of the skin from UV-induced (including photo-oxidative damage is a beneficial physiological effect. The applicant identified one bioequivalence study as being pertinent to the health claim. The Panel notes that this study did not assess direct measures of UV-induced (including photo-oxidative skin damage. Therefore, no conclusions could be drawn from this study for the scientific substantiation of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of lycopene, vitamin E, lutein and selenium and protection of the skin from UV-induced (including photo-oxidative damage.

  6. Synthesis and biological evaluation of nitric oxide-releasing sixalkoxyl biphenyl derivatives as anticancer agents

    Institute of Scientific and Technical Information of China (English)

    Xiang Wen Kong; Yi Hua Zhang; Li Dai; Hui Ji; Yi Sheng Lai; Si Xun Peng

    2008-01-01

    A series of novel nitric oxide-donating sixalkoxyl biphenyl derivatives (14a-i)were synthesized by coupling furoxan with alkoxyl biphenyl skeleton using amino acids as the spacers,and their cytotoxicity against HepG2 cells in vitro were evaluated by MTr method.It was found that 14c,14d,14f,14i,14j and 14k showed more potent cytotoxic activities than control 5-fluorouracil.NO release assay of target compounds indicated that the maximum amount of NO released by most active compounds 14c and 14j was about 6 x 10-2μmol/L,whereas 14a and 14h with very weak activity only released NO of 1 x 10-μmol/L.

  7. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  8. Oxidation of Mixed Active Pharmaceutical Ingredients in Biologically Treated Wastewater by ClO2

    DEFF Research Database (Denmark)

    Moradas, Gerly; Fick, Jerker; Ledin, Anna

    2011-01-01

    Biologically treated wastewater containing a mixture of 53 active pharmaceutical ingredients (APIs)was treated with 0-20 mg/l chlorine dioxide (ClO2) solution. Wastewater effluents were taken from two wastewater treatment plants in Sweden, one with (low COD) and one without (high COD) extended...... removed at 5 mg/l ClO2 dose. Removal of the same APIs from the high COD effluent was observed when the ClO2 dose was increased to 1.25 mg/l and an increase in API removal only after treatment with 8 mg/l ClO2. This illustrates that treatment of wastewater effluents with chlorine dioxide has potential...... to remove pharmaceuticals traces from wastewater treatment plant effluents....

  9. Occupational cosmic radiation exposure in Portuguese airline pilots: study of a possible correlation with oxidative biological markers.

    Science.gov (United States)

    Silva, Rodrigo; Folgosa, Filipe; Soares, Paulo; Pereira, Alice S; Garcia, Raquel; Gestal-Otero, Juan Jesus; Tavares, Pedro; Gomes da Silva, Marco D R

    2013-05-01

    Several studies have sought to understand the health effects of occupational exposure to cosmic radiation. However, only few biologic markers or associations with disease outcomes have so far been identified. In the present study, 22 long- and 26 medium-haul male Portuguese airline pilots and 36 factory workers who did not fly regularly were investigated. The two groups were comparable in age and diet, were non-smokers, never treated with ionizing radiation and other factors. Cosmic radiation exposure in pilots was quantified based on direct monitoring of 51 flights within Europe, and from Europe to North and South America, and to Africa. Indirect dose estimates in pilots were performed based on the SIEVERT (Système informatisé d'évaluation par vol de l'exposition au rayonnement cosmique dans les transports aériens) software for 6,039 medium- and 1,366 long-haul flights. Medium-haul pilots had a higher cosmic radiation dose rate than long-haul pilots, that is, 3.3 ± 0.2 μSv/h and 2.7 ± 0.3 μSv/h, respectively. Biological tests for oxidative stress on blood and urine, as appropriate, at two time periods separated by 1 year, included measurements of antioxidant capacity, total protein, ferritin, hemoglobin, creatinine and 8-hydroxy-2-deoxyguanosine (8OHdG). Principal components analysis was used to discriminate between the exposed and unexposed groups based on all the biological tests. According to this analysis, creatinine and 8OHdG levels were different for the pilots and the unexposed group, but no distinctions could be made among the medium- and the long-haul pilots. While hemoglobin levels seem to be comparable between the studied groups, they were directly correlated with ferritin values, which were lower for the airline pilots.

  10. Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

    Science.gov (United States)

    Feng, Pei; Wei, Pingpin; Shuai, Cijun; Peng, Shuping

    2014-01-01

    A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2), and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

  11. Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

    Directory of Open Access Journals (Sweden)

    Pei Feng

    Full Text Available A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP scaffolds via selective laser sintering (SLS. We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO. Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2, and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF, indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

  12. Climatic, tectonic, and biological factors affecting the oxidation state of the atmosphere and oceans: Implications for Phanerozoic O2 evolution

    Science.gov (United States)

    Ozaki, K.; Tajika, E.

    2015-12-01

    also shed light on the causal linkage between the critical biological evolution (such as an establishment of biological pump and advent of land plant) and the oxidation state of the atmosphere and oceans.

  13. Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H₂O₂ for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry.

    Science.gov (United States)

    Bezerra, Marcos A; Souza, Antônio D S; Oliveira, Rafael V; Oliveira, Djalma M; Cardoso, Luiz A M; Sousa Filho, Hélio R

    2015-03-01

    This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS). Three variables (pH, irradiation time and buffer concentration) were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v) were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1) were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

  14. Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H2O2 for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Marcos A. Bezerra

    2015-03-01

    Full Text Available This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS. Three variables (pH, irradiation time and buffer concentration were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1 were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

  15. Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Chevremont, A.-C., E-mail: anne-celine.chevremont@imbe.fr [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France); Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Farnet, A.-M. [Aix-Marseille Universite - CNRS, FR ECCOREV, Institut Mediterraneen de Biodiversite et d' Ecologie marine et continentale (UMR7263), Equipe ' Vulnerabilite des Systemes Microbiens' , Avenue Escadrille Normandie-Niemen, Boite 452, 13397 Marseille Cedex 20 (France); Coulomb, B.; Boudenne, J.-L. [Aix-Marseille Universite - CNRS, FR ECCOREV, Laboratoire Chimie de l' Environnement (FRE3416), Equipe ' Developpements Metrologiques et Chimie des Milieux' , 3 place Victor Hugo, case 29, 13331 Marseille Cedex 3 (France)

    2012-06-01

    Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO{sub 2}. - Highlights: Black-Right-Pointing-Pointer We test UV-LEDs as an urban wastewater tertiary treatment. Black-Right-Pointing-Pointer UV-A and UV-C are coupled, combining germicidal and oxidative properties of UV. Black-Right-Pointing-Pointer Coupled wavelengths have the most efficient bactericidal effect. Black-Right-Pointing-Pointer Coupling UV-A and UV-C leads to photooxidation of creatinine and phenol.

  16. Substrate activation for O2 reactions by oxidized metal centers in biology.

    Science.gov (United States)

    Pau, Monita Y M; Lipscomb, John D; Solomon, Edward I

    2007-11-20

    The uncatalyzed reactions of O(2) (S = 1) with organic substrates (S = 0) are thermodynamically favorable but kinetically slow because they are spin-forbidden and the one-electron reduction potential of O(2) is unfavorable. In nature, many of these important O(2) reactions are catalyzed by metalloenzymes. In the case of mononuclear non-heme iron enzymes, either Fe(II) or Fe(III) can play the catalytic role in these spin-forbidden reactions. Whereas the ferrous enzymes activate O(2) directly for reaction, the ferric enzymes activate the substrate for O(2) attack. The enzyme-substrate complex of the ferric intradiol dioxygenases exhibits a low-energy catecholate to Fe(III) charge transfer transition that provides a mechanism by which both the Fe center and the catecholic substrate are activated for the reaction with O(2). In this Perspective, we evaluate how the coupling between this experimentally observed charge transfer and the change in geometry and ligand field of the oxidized metal center along the reaction coordinate can overcome the spin-forbidden nature of the O(2) reaction.

  17. Zinc Oxide Nanocrystals for Non-resonant Nonlinear Optical Microscopy in Biology and Medicine.

    Science.gov (United States)

    Kachynski, Aliaksandr V; Kuzmin, Andrey N; Nyk, Marcin; Roy, Indrajit; Prasad, Paras N

    2008-07-24

    In this paper we show that biocompatible zinc oxide (ZnO) nanocrystals (NCs) having non-centrosymmetric structure can be used as non-resonant nonlinear optical probes for targeting in bioimaging applications in vitro by use of the second order processes of second harmonic and sum frequency generation, as well as the third order process of four wave mixing. These non-resonant processes provide advantages above and beyond traditional two-photon bioimaging: (i) the probes do not photo-bleach; (ii) the input wavelength can be judiciously selected; and (iii) no heat is dissipated into the cells, ensuring longer cell viability and ultimately longer imaging times. ZnO NCs have been synthesized in organic media by using a non-hydrolytic sol-gel process, and subsequently dispersed in aqueous media using phospholipid micelles, and incorporated with the biotargeting molecule folic acid (FA). Sum Frequency, Second Harmonic and non-resonant four wave mixing non-linear signals from this stable dispersion of ZnO NCs, targeted to the live tumor (KB) cells were used for imaging. Robust intracellular accumulation of the targeted (FA incorporated) ZnO nanocrystals could be observed, without any indication of cytotoxicity.

  18. UV氧化-生物强化MBR耦合工艺处理模拟印染废水%Study on the treatment of simulated dyeing wastewater by the coupled UV oxidation and bio-augmented MBR process

    Institute of Scientific and Technical Information of China (English)

    陈桂娥; 李啸寰; 许振良

    2011-01-01

    The membrane bioreactor (MBR) coupled with UV oxidation system has been used for treating simulated dyeing wastewater. The effects of the treatment effectivenss and bio-augmentation capacity on MBR process have been studied. MBR system is to be operated under the conditions of T=25 ℃,pH=6,HRT=10 h and DO=3~5 mg/L, running time 60 d,and the augmented strains are dosed into MBR in a certain proportion of 0.5%. The results illustrate that the UV oxidation lowers the toxicity of the wastewater greatly, and the total average removal rate of TOC reaches 89%. The effluent water quality is pretty good. Moreover,bio-augmentation makes the activated sludge take on better physiological activity and anti-shock loading capability.%采用UV氧化+膜生物反应器(MBR)组合工艺处理模拟印染废水,考察了该工艺的处理效果及生物强化作用对MBR工艺的影响.MBR实验条件为:水温25℃,pH=6,水力停留时间10h,溶解氧3~5 mg/L,运行时间60d,强化菌种按质量分数0.5%投入到MBR.实验结果表明,UV氧化大大降低了废水的毒性,组合工艺对TOC的总平均去除率达到89%,出水水质良好.此外,生物强化使活性污泥具有更好的生理活性和抗冲击负荷能力.

  19. 高强紫外球形灯光解氧化硫化氢气体%Photolysis and oxidation of hydrogen sulfide gas using high-intensity UV spherical lamp

    Institute of Scientific and Technical Information of China (English)

    丁德才; 陆钢; 刘鹏; 汪剑锋; 李朝林

    2012-01-01

    A photolysis and oxidation method using high-intensity UV spherical lamp for removal of H2S gas was proposed. The effects of initial concentration of H2S, humidity, oxygen ratio, retention time on the removal of H2S were investigated. Under low H2S concetration levels, the removal of H2S was up to 99%. In the reaction system, humidity had greater effect on H2S removal than oxygen content. The optimum ran- ges of humidity and retention time were 45% - 60% and 6 - 10 s, respectively. In the H2S removal process, the UV lamp could directly photolyze and oxidize H2S, and the two reactions had synergistic effects.%提出了采用可产臭氧的高强球形紫外灯光解氧化硫化氢气体。考察了硫化氢初始浓度、湿度、含氧量、停留时间对硫化氢去除效率的影响。实验结果表明,硫化氢浓度在低浓度范围内,对硫化氢的去除效率可以达到99%以上。反应体系内气体湿度比含氧量对硫化氢的去除效率的影响更明显。气体湿度控制在45%~60%和反应停留时间控制在6~10s范围内为最佳。高强紫外球形灯处理硫化氢过程分别存在直接光解和臭氧氧化作用及两者的协同作用。

  20. Enhancing ethylbenzene vapors degradation in a hybrid system based on photocatalytic oxidation UV/TiO{sub 2}-In and a biofiltration process

    Energy Technology Data Exchange (ETDEWEB)

    Hinojosa-Reyes, M. [Instituto Potosino de Investigacion Cientifica y Tecnologica A.C., Division de Ciencias Ambientales, Camino a la Presa San Jose 2055, Lomas 4a seccion, CP. 78216, San Luis Potosi, S.L.P. (Mexico); Rodriguez-Gonzalez, V. [Instituto Potosino de Investigacion Cientifica y Tecnologica A.C., Division de Materiales Avanzados, Camino a la Presa San Jose 2055, Lomas 4a seccion, CP. 78216, San Luis Potosi, S.L.P. (Mexico); Arriaga, S., E-mail: sonia@ipicyt.edu.mx [Instituto Potosino de Investigacion Cientifica y Tecnologica A.C., Division de Ciencias Ambientales, Camino a la Presa San Jose 2055, Lomas 4a seccion, CP. 78216, San Luis Potosi, S.L.P. (Mexico)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer The best photocatalytic system for EB degradation was based on TiO{sub 2}-In 1%/365 nm. Black-Right-Pointing-Pointer A maximum EC of 290 g m{sup -3} h{sup -1} for the hybrid system was obtained. Black-Right-Pointing-Pointer The hybrid process enhanced 40% the overall EC of ethylbenzene. Black-Right-Pointing-Pointer An overall mineralization of 67% for EB degradation was reached in the hybrid system. - Abstract: The use of hybrid processes for the continuous degradation of ethylbenzene (EB) vapors has been evaluated. The hybrid system consists of an UV/TiO{sub 2}-In photooxidation coupled with a biofiltration process. Both the photocatalytic system using P25-Degussa or indium-doped TiO{sub 2} catalysts and the photolytic process were performed at UV-wavelengths of 254 nm and 365 nm. The experiments were carried out in an annular plug flow photoreactor packed with granular perlite previously impregnated with the catalysts, and in a glass biofilter packed with perlite and inoculated with a microbial consortium. Both reactors were operated at an inlet loading rate of 127 g m{sup -3} h{sup -1}. The greatest degradation rate of EB (0.414 ng m{sup -2} min{sup -1}) was obtained with the TiO{sub 2}-In 1%/365 nm photocatalytic system. The elimination capacity (EC) obtained in the control biofilter had values {approx}60 g m{sup -3} h{sup -1}. Consequently, the coupled system was operated for 15 days, and a maximal EC of 275 g m{sup -3} h{sup -1}. Thus, the results indicate that the use of hybrid processes enhanced the EB vapor degradation and that this could be a promising technology for the abatement of recalcitrant volatile organic compounds.