WorldWideScience

Sample records for formaldehyde

  1. Melamine-formaldehyde aerogels

    Science.gov (United States)

    Pekala, Richard Walter

    1992-01-01

    Organic aerogels that are transparent and essentially colorless are prepa from the aqueous, sol-gel polymerization of melamine with formaldehyde. The melamine-formaldehyde (MF) aerogels have low densities, high surface areas, continuous porsity, ultrafine cell/pore sizes, and optical clarity.

  2. Microfabricated Formaldehyde Gas Sensors

    Directory of Open Access Journals (Sweden)

    Karen C. Cheung

    2009-11-01

    Full Text Available Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation.

  3. Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

    DEFF Research Database (Denmark)

    de Groot, Anton C; Flyvholm, Mari-Ann; Lensen, Gerda

    2009-01-01

    in the literature as formaldehyde-releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency....... The frequency of contact allergy to formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test...

  4. Formaldehyde in reusable protective gloves.

    Science.gov (United States)

    Pontén, Ann

    2006-05-01

    Due to the clinical findings in a single patient's case, formaldehyde was suspected to be present in clinically relevant levels in reusable protective gloves. Therefore, 9 types of gloves were investigated with the semi-quantitative chromotropic acid method. It was found that 6/9 gloves emitted some formaldehyde and that 4/9 gloves emitted > or =40 microg of formaldehyde. Most of the formaldehyde was found on the inside of the gloves. To get an indication of the clinical relevance, a comparison with a protective cream declared to contain the formaldehyde-releasing agent diazolidinyl urea was performed by comparing areas of gloves with areas of cream layers with thickness 1-2 mg/cm(2). It was found that the amounts of formaldehyde emitted from the gloves might be in the same range as emitted from a layer of cream.

  5. Emission of formaldehyde from furniture

    DEFF Research Database (Denmark)

    Andersen, Helle Vibeke; Klinke, Helene B.; Funch, Lis Winther

    The emission of formaldehyde from 20 pieces of furniture, representing a variety of types, was measured in climate chambers. Most tests show low emissions but certain scenarios of furnishing, including furniture with large surface areas in relation to room volume can emit formaldehyde resulting...

  6. 78 FR 34795 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-06-10

    ... Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products... Certification Framework for the Formaldehyde Standards for Composite Wood Products AGENCY: Environmental... certification, auditing and reporting of third-party certifiers, recordkeeping, enforcement, laminated products...

  7. Absorption of formaldehyde in water

    NARCIS (Netherlands)

    Winkelman, Jozef Gerhardus Maria

    2003-01-01

    Deze dissertatie beschrijft theoretisch en experimenteel werk aan de absorptie van formaldehyde in water. Met resultaten hiervan zijn chemisch-technische modellen ontwikkeld voor de beschrijving en optimalisatie van industriële formaldehydeabsorbeurs. Deze samenvatting geeft eerst algemene

  8. Adsorption of formaldehyde on graphene and graphyne

    Science.gov (United States)

    Majidi, R.; Karami, A. R.

    2014-05-01

    The adsorption of formaldehyde on graphene and graphyne was investigated to search high sensitivity sensors for detection of formaldehyde. We have used density functional theory to study the effect of formaldehyde on the electronic properties of graphene and graphyne. It is found that formaldehyde is physisorbed on the graphene and graphyne with small binding energy, large binding distance, and small charge transfer. The calculations also indicate that formaldehyde adsorption modifies the electronic properties of semimetallic graphene, α-graphyne, and β-graphyne and semiconducting γ-graphyne. The graphene and graphyne show semiconducting property in the presence of formaldehyde. The effect of formaldehyde on the electronic properties of graphene and graphyne suggests the potential application of these carbon nanomaterials for formaldehyde detection.

  9. 7746 CONCENTRATIONS OF FORMALDEHYDE IN RAIN WATERS ...

    African Journals Online (AJOL)

    Win7Ent

    2013-06-03

    Jun 3, 2013 ... The chromotropic acid method described by the. National Institute for ... concentration range of the formaldehyde in the rain waters varied from month to month throughout the six ... vicinity of vegetation [3]. Formaldehyde is the ...

  10. 78 FR 44090 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-07-23

    ... Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products..., concerning a third-party certification framework for the formaldehyde standards for composite wood products... Environmental protection, Composite wood products, Formaldehyde, Reporting and recordkeeping, Third-party...

  11. Formaldehyde concentration in diagnostic patch testing

    DEFF Research Database (Denmark)

    Trattner, A; Johansen, J D; Menné, T

    1998-01-01

    Exposure to formaldehyde is common from both consumer products and industry. The reliability of the patch test is essential for the diagnosis of formaldehyde allergy as it is difficult to suspect from the patient's history. The recommended formaldehyde patch test concentration has been reduced over...

  12. Nuclear spin conversion in formaldehyde

    OpenAIRE

    Chapovsky, Pavel L.

    2000-01-01

    Theoretical model of the nuclear spin conversion in formaldehyde (H2CO) has been developed. The conversion is governed by the intramolecular spin-rotation mixing of molecular ortho and para states. The rate of conversion has been found equal 1.4*10^{-4}~1/s*Torr. Temperature dependence of the spin conversion has been predicted to be weak in the wide temperature range T=200-900 K.

  13. Formaldehyde in the Galactic Centre

    International Nuclear Information System (INIS)

    Cohen, R.J.; Few, R.W.

    1981-01-01

    Formaldehyde 6-cm absorption in the direction of the Galactic Centre has been surveyed using the Jodrell Bank MK II radio telescope (beam-width 10 x 9 arcmin). The observations sample the region - 2 0 = 0 and - 0 0 .5 = 0 .5, with a velocity range of 620 km s -1 , a velocity resolution of 2.1 km s -1 and an rms noise level of approximately 0.03 K. The data are presented as contour maps showing line temperature as a function of latitude and velocity (b-V maps) and as a function of longitude and velocity (l-V maps). Similar maps of the line-to-continuum ratio are also presented. The radial distribution of formaldehyde (H 2 CO) in the Galactic Centre region is derived using two different kinematic models which give similar results. Formaldehyde is strongly concentrated in the Galactic Centre in a layer of latitude extent approximately 0 0 .5 and longitude extent approximately 4 0 which contains one quarter of all the H 2 CO in the Galaxy. The distribution is centred on l approximately 1 0 . The individual H 2 CO features are described in detail. (author)

  14. 78 FR 51696 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-08-21

    ... Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products..., concerning a third-party certification framework for the formaldehyde standards for composite wood products... INFORMATION CONTACT. List of Subjects in 40 CFR Part 770 Environmental protection, Composite wood products...

  15. Initial inventory of alternatives to biocidal products containing formaldehyde of formaldehyde releasers

    NARCIS (Netherlands)

    Wezenbeek JM; Janssen MPM; Scheepmaker JWA; MSP; M&V

    2015-01-01

    Formaldehyde is de werkzame stof in veel desinfecteer- en conserveringsmiddelen, maar deze stof is kankerverwekkend. Daarom zal formaldehyde naar verwachting per 1 januari 2016 op Europees niveau als zodanig worden geclassificeerd (carcinogeen 1B). Dit kan betekenen dat formaldehyde-houdende

  16. Formaldehyde Emissions from Urea-Formaldehyde- and no-added-formaldehyde-Bonded particleboard as Influenced by Temperature and Relative Humidity

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Timothy L. Chaffee; Kyle M. Gonner

    2012-01-01

    It is well documented that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF)–type adhesives. This work investigates the effect of temperature and humidity on newer commercial California Air Resources Board (CARB) phase II–compliant particleboard produced with UF-type adhesives. These...

  17. Photochemical decomposition of Formaldehyde in solution

    International Nuclear Information System (INIS)

    Garrido Z, G.

    1995-01-01

    In this work was studied the effect of ultraviolet radiation produced by a mercury low pressure lamp in solutions of formaldehyde. These solutions were exposed to ultraviolet rays at different times. In some of these series of solutions was added a photosensibilizer in order to obtain a high photodecomposition of formaldehyde. The techniques used for determine the products of the decomposition were the following: 1. In order to measure the residual formaldehyde and glioxal, the Hantzsch and 2,4-dinitrophenylhydrazine methods were used. 2. pH's measurements of the solutions, before and after exposition. 3. Paper's chromatography for determine presence of formed acids. 4. Acid-base tritiations for measure total acidification. We observed that when the time of exposition to UV rays was increased, a high photodecomposition of formaldehyde was formed and, besides, a greater quantity of another products. Of the reagents used like photosensibilizers, with the ruthenium reagent, the best results were obtained. (Author)

  18. short communication quantitative determination of formaldehyde

    African Journals Online (AJOL)

    Preferred Customer

    irritation, respiration, asthma and pulmonary edema have been reported previously [1]. ... for improving the capabilities, performing more reliable models and achieving more ... Formaldehyde was added to the Fluoral P solution in a 1:1 volume.

  19. Compact, Ultrasensitive Formaldehyde Monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase I proposal seeks to develop an ultrasensitive, laser-based formaldehyde gas sensor system for airborne and ground-based...

  20. Formaldehyde's Impact on Indoor Air Quality

    Science.gov (United States)

    Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes.

  1. Radiation thermal transformations of formaldehyde in alcohols

    International Nuclear Information System (INIS)

    Vetrov, V.S.; Korolev, V.M.; Koroleva, G.N.; Likholap, V.F.; Khomich, F.G.

    1978-01-01

    The effect of acid and reactor gamma radiation on the interaction of formaldehyde and methanol has been studied. The radiation-thermal investigations were carried out in the range of temperatures from 150 to 230 deg C. A dose rate of n,γ-radiation amounted to 2.4x10 17 eV (gxs). From the data obtained it is concluded that the 0.01-0.1 M formic acid addition and irradiation of the methanol-formaldehyde mixture result in a substantial increase in formaldehyde consumption, the acid addition increasing the rate of formaldehyde consumption in about two times; the n,γ-radiation effect is much powerful. The rate of methylal formation increases in the presence of acid and at the temperature rise; its maximum is formed in the range of 180-190 deg C. The methyl formiate formation increases with the acid addition and temperature rise. It is concluded that radiolytic protons can accelerate methylal formation from methanol-formaldehyde solutions. The temperature rise results in the concentration increase in a free form of formaldehyde and the formation of methylal and methyl formiate

  2. Estimation of formaldehyde concentration in working environment by using 14C-labeled formaldehyde

    International Nuclear Information System (INIS)

    Hamada, Masana; Kitano, Katsuhiro; Miketa, Daigo

    2010-01-01

    It became to be ruled to check the concentration of formaldehyde as the estimation of airborne concentration in working environment since March, 2009 and then, liquid chromatography and easily analyzing equipment methods, mainly gas detector tube method, are given as the official methods. When we estimate the airborne formaldehyde concentration in a work place where only formalin is used as a formaldehyde emission source such as a room for pathological examination, it is not necessary to separate formaldehyde and therefore not very reasonable to use liquid chromatography including troublesome procedures. On the other hand, gas detector tube method is convenient but has possibility of causing errors by individual differences. The errors might cause the additional differences of the control classes and of the measures to prevent workers from being exposed to harmful materials. In order to solve these problems and to exam alternative analyzing method for formaldehyde, we tried to measure the concentration by using 14 C-labelled one. After 14 C-labelled formaldehyde solution is put into the emission source of formaldehyde (formalin solution), the vaporized samples are taken by silica gel tubes quantitatively as usual at the estimation of airborne concentration in working environment. By counting the desorpted amount of radioactivity from silica gel, it was revealed that the obtained concentrations of formaldehyde are correspond to both the calculated values and the values indicated on the gas detector tubes at various concentrations. In this study, we used the amount below the lower activity limits of radioactive material. Except the users who have radioisotope controlled area, we are allowed to use 14 C-labeled materials below 10 MBq without being regulated under the Law Concerning Prevention of Radiation Hazards. When we use a little amount of 14 C-formaldehyde at formaldehyde using area to check the concentration of vaporized formaldehyde, this method was found to

  3. Formaldehyde OMI operational retrieval upgrades

    Science.gov (United States)

    Gonzalez Abad, G.; Chance, K.; Liu, X.

    2013-05-01

    Total column of formaldehyde (HCHO), a proxy for biogenic emissions, can be observed from satellites using the ultraviolet region of the spectrum. The operational HCHO retrievals from the Ozone Monitoring Instrument (OMI) on board the AURA satellite, part of NASA's A-train constellation of Earth Observing satellites, are described. The operational retrieval, based on a basic optical absorption spectroscopy (BOAS) algorithm, has been affected by the degradation of the instrument especially from 2008 onwards. The most significant problems are the unrealistic increasing high background concentrations of HCHO retrieved from OMI and the row anomaly. An upgrade for the original operational algorithm is therefore needed to ensure its trend quality and to account for these difficulties. The strategies implemented to deal with the instrumental degradation are presented here. Air mass factors (AMFs) in the current fitting window show significant wavelength dependence. Fitting uncertainties can potentially be improved by including shorter wavelengths as long as the AMFs wavelength dependence is taken into account. As part of these improvements a look-up table of wavelength-dependent AMFs have been calculated. Using this new table it is possible to retrieve the HCHO total column directly, weighting the HCHO cross sections with the wavelength-dependent AMFs. Additionally, the pixels affected by the row anomaly are now flagged in the level 2 data generated with the upgraded algorithm.

  4. Modeling Formaldehyde Emission in Comets

    Science.gov (United States)

    Disanti, M. A.; Reuter, D. C.; Bonev, B. P.; Mumma, M. J.; Villanueva, G. L.

    Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of these show clear emission from H2CO. We also detected H2CO with NIRSPEC in one Jupiter Family comet, 9P/Tempel 1, during Deep Impact observations. Our H2CO model, originally developed to interpret low-resolution spectra of comets Halley and Wilson (Reuter et al. 1989 Ap J 341:1045), predicts individual line intensities (g-factors) as a function of rotational temperature for approximately 1300 lines having energies up to approximately 400 cm^-1 above the ground state. Recently, it was validated through comparison with CSHELL spectra of C/2002 T7 (LINEAR), where newly developed analyses were applied to obtain robust determinations of both the rotational temperature and abundance of H2CO (DiSanti et al. 2006 Ap J 650:470). We are currently in the process of extending the model to higher rotational energy (i.e., higher rotational quantum number) in an attempt to improve the fit to high-J lines in our spectra of C/T7 and other comets. Results will be presented, and implications discussed.Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of

  5. Teratogenic effect of formaldehyde in rabbits

    Directory of Open Access Journals (Sweden)

    A. A. Al–Saraj

    2009-01-01

    Full Text Available Thirty three pregnant rabbits were exposed to vapour of 10% formaldehyde (12 ppm throughout the gestation period to know its effect on newborns. The results showed no abortion or foetal mortality but there were some anomalies (23.8% among the newborns rabbits which includes: meromelia (6.8%, encephalocele (6.1%, Oligodactyly (4.1%, Umbilical hernia (3.4% and Short tail (3.4%; besides that small for date and decrease in the body weight of the newborns were also noticed. These findings suggest that formaldehyde is a teratogenic agent.

  6. the histological effects of formaldehyde vapour on the lungs

    African Journals Online (AJOL)

    Uwaifoh

    2012-12-31

    Dec 31, 2012 ... In the world day, the active chemical used for embalming is formaldehyde. ... formaldehyde causes nasopharyngeal cancer in humans,” (Collins et al., 1997; Gardner et ... pattern for inhalation of formaldehyde in rats presented cell ... temperature of about 25-28oC and photo-periodicity of 12h day/ 12h night.

  7. 78 FR 34820 - Formaldehyde Emissions Standards for Composite Wood Products

    Science.gov (United States)

    2013-06-10

    .... Examples of sources of formaldehyde gas inside homes include cigarette smoke, unvented, fuel- burning... derived an inhalation unit risk factor for assessing formaldehyde cancer risk. The risk factor and... formaldehyde by inhalation (Ref. 8). This draft IRIS assessment was peer-reviewed by the National Research...

  8. 29 CFR 1910.1048 - Formaldehyde.

    Science.gov (United States)

    2010-07-01

    ... resolve their disagreement, then the employer and the employee through their respective physicians shall... the disagreement of the prior physicians. (v) In the alternative, the employer and the employee or.... Employee exposure means the exposure to airborne formaldehyde which would occur without corrections for...

  9. Identification of formaldehyde-responsive genes by suppression subtractive hybridization

    International Nuclear Information System (INIS)

    Lee, Min-Ho; Kim, Young-Ae; Na, Tae-Young; Kim, Sung-Hye; Shin, Young Kee; Lee, Byung-Hoon; Shin, Ho-Sang; Lee, Mi-Ock

    2008-01-01

    Formaldehyde is frequently used in indoor household and occupational environments. Inhalation of formaldehyde invokes an inflammatory response, including a variety of allergic signs and symptoms. Therefore, formaldehyde has been considered as the most prevalent cause of sick building syndrome, which has become a major social problem, especially in developing urban areas. Further formaldehyde is classified as a genotoxicant in the respiratory tract of rats and humans. To better understand the molecular mechanisms involved in formaldehyde intoxication, we sought differentially regulated genes by formaldehyde exposure to Hs 680.Tr human trachea cells, using polymerase chain reaction (PCR)-based suppression subtractive hybridization. We identified 27 different formaldehyde-inducible genes, including those coding for the major histocompatibility complex, class IA, calcyclin, glutathione S-transferase pi, mouse double minute 2 (MDM2), platelet-derived growth factor receptor alpha, and which are known to be associated with cell proliferation and differentiation, immunity and inflammation, and detoxification. Induction of these genes by formaldehyde treatment was confirmed by reverse transcription PCR and western blot analysis. Further, the expression of calcyclin, glutathione S-transferase pi, PDGFRA and MDM2 were significantly induced in the tracheal epithelium of Sprague Dawley rats after formaldehyde inhalation. Our results suggest that the elevated levels of these genes may be associated with the formaldehyde-induced toxicity, and that they deserve evaluation as potential biomarkers for formaldehyde intoxication

  10. The microcapsule-type formaldehyde scavenger: the preparation and the application in urea-formaldehyde adhesives.

    Science.gov (United States)

    Duan, Hongyun; Qiu, Teng; Guo, Longhai; Ye, Jun; Li, Xiaoyu

    2015-08-15

    The limitation and regulation of formaldehyde emissions (FE) now shows great importance in wood-based materials such as plywood and particle board manufactured for building and furnishing materials. The widely used formaldehyde-based adhesives are one of the main sources of FE from the wood products. In this work, a new kind of long-term effective formaldehyde scavenger in the microcapsule form was prepared by using an intra-liquid desiccation method. The characterizations of the capsule (UC) were performed including the morphologies, the yields, the loading efficiency as well as its sustained-release of urea in aqueous conditions. The prepared UC could be integrated in urea-formaldehyde resins by simply physical blending, and the mixtures were available to be applied as the adhesives for the manufacture of plywood. The bonding strength (BS) and the FE of the bonded plywood in both short (3h) and long (12 week) period were evaluated in detail. It was found that the FE profile of the plywood behaved following a duple exponential law within 12 week. The addition of UC in the adhesive can effectively depress the FE of the plywood not only in a short period after preparation but also in a long-term period during its practical application. The slow released urea would continuously suppress the emission of toxic formaldehyde in a sustained manner without obviously deteriorating on the BS of the adhesives. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Release rate of diazinon from microcapsule based on melamine formaldehyde

    Science.gov (United States)

    Noviana Utami C., S.; Rochmadi

    2018-04-01

    The microcapsule containing diazinon as the core material and melamine formaldehyde as the membrane material have been synthesized by in situ polymerization method. The microcapsule membrane in this research is melamine formaldehyde (MF). This research aims to study the effect of pH and temperature on the release rate of diazinon from microcapsule based on melamine formaldehyde in aqueous medium. The results showed that pH and temperature has little effect on the release rate of diazinon from microcapsule based on melamine formaldehyde. This is due to the diffusion through the microcapsule membrane is not influenced by the pH and temperature of the solution outside of microcapsule.

  12. Degradation of formaldehyde in anaerobic sequencing batch biofilm reactor (ASBBR)

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, N.S. [Laboratorio de Processos Biologicos (LPB), Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos (EESC), Universidade de Sao Paulo - USP, Engenharia Ambiental, Bloco 4-F, Av. Joao Dagnone, 1100 Santa Angelina, 13.563-120 Sao Carlos, SP (Brazil); Zaiat, M. [Laboratorio de Processos Biologicos (LPB), Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos (EESC), Universidade de Sao Paulo - USP, Engenharia Ambiental, Bloco 4-F, Av. Joao Dagnone, 1100 Santa Angelina, 13.563-120 Sao Carlos, SP (Brazil)], E-mail: zaiat@sc.usp.br

    2009-04-30

    The present study evaluated the degradation of formaldehyde in a bench-scale anaerobic sequencing batch reactor, which contained biomass immobilized in polyurethane foam matrices. The reactor was operated for 212 days at 35 deg. C with 8 h sequential cycles, under different affluent formaldehyde concentrations ranging from 31.6 to 1104.4 mg/L (formaldehyde loading rates from 0.08 to 2.78 kg/m{sup 3} day). The results indicate excellent reactor stability and over 99% efficiency in formaldehyde removal, with average effluent formaldehyde concentration of 3.6 {+-} 1.7 mg/L. Formaldehyde degradation rates increased from 204.9 to 698.3 mg/L h as the initial concentration of formaldehyde was increased from around 100 to around 1100 mg/L. However, accumulation of organic matter was observed in the effluent (chemical oxygen demand (COD) values above 500 mg/L) due to the presence of non-degraded organic acids, especially acetic and propionic acids. This observation poses an important question regarding the anaerobic route of formaldehyde degradation, which might differ substantially from that reported in the literature. The anaerobic degradation pathway can be associated with the formation of long-chain oligomers from formaldehyde. Such long- or short-chain polymers are probably the precursors of organic acid formation by means of acidogenic anaerobic microorganisms.

  13. Development of a formaldehyde biosensor with application to synthetic methylotrophy.

    Science.gov (United States)

    Woolston, Benjamin M; Roth, Timothy; Kohale, Ishwar; Liu, David R; Stephanopoulos, Gregory

    2018-01-01

    Formaldehyde is a prevalent environmental toxin and a key intermediate in single carbon metabolism. The ability to monitor formaldehyde concentration is, therefore, of interest for both environmental monitoring and for metabolic engineering of native and synthetic methylotrophs, but current methods suffer from low sensitivity, complex workflows, or require expensive analytical equipment. Here we develop a formaldehyde biosensor based on the FrmR repressor protein and cognate promoter of Escherichia coli. Optimization of the native repressor binding site and regulatory architecture enabled detection at levels as low as 1 µM. We then used the sensor to benchmark the in vivo activity of several NAD-dependent methanol dehydrogenase (Mdh) variants, the rate-limiting enzyme that catalyzes the first step of methanol assimilation. In order to use this biosensor to distinguish individuals in a mixed population of Mdh variants, we developed a strategy to prevent cross-talk by using glutathione as a formaldehyde sink to minimize intercellular formaldehyde diffusion. Finally, we applied this biosensor to balance expression of mdh and the formaldehyde assimilation enzymes hps and phi in an engineered E. coli strain to minimize formaldehyde build-up while also reducing the burden of heterologous expression. This biosensor offers a quick and simple method for sensitively detecting formaldehyde, and has the potential to be used as the basis for directed evolution of Mdh and dynamic formaldehyde control strategies for establishing synthetic methylotrophy. © 2017 Wiley Periodicals, Inc.

  14. Degradation of formaldehyde in anaerobic sequencing batch biofilm reactor (ASBBR)

    International Nuclear Information System (INIS)

    Pereira, N.S.; Zaiat, M.

    2009-01-01

    The present study evaluated the degradation of formaldehyde in a bench-scale anaerobic sequencing batch reactor, which contained biomass immobilized in polyurethane foam matrices. The reactor was operated for 212 days at 35 deg. C with 8 h sequential cycles, under different affluent formaldehyde concentrations ranging from 31.6 to 1104.4 mg/L (formaldehyde loading rates from 0.08 to 2.78 kg/m 3 day). The results indicate excellent reactor stability and over 99% efficiency in formaldehyde removal, with average effluent formaldehyde concentration of 3.6 ± 1.7 mg/L. Formaldehyde degradation rates increased from 204.9 to 698.3 mg/L h as the initial concentration of formaldehyde was increased from around 100 to around 1100 mg/L. However, accumulation of organic matter was observed in the effluent (chemical oxygen demand (COD) values above 500 mg/L) due to the presence of non-degraded organic acids, especially acetic and propionic acids. This observation poses an important question regarding the anaerobic route of formaldehyde degradation, which might differ substantially from that reported in the literature. The anaerobic degradation pathway can be associated with the formation of long-chain oligomers from formaldehyde. Such long- or short-chain polymers are probably the precursors of organic acid formation by means of acidogenic anaerobic microorganisms

  15. Concentrations of formaldehyde in rain waters harvested at the ...

    African Journals Online (AJOL)

    Formaldehyde has been recognized as one of the most important pollutants and a carcinogen that is present in the air, water, foods, soils, fabrics, cosmetics, cigarette smoke and treated wood. Related health effects and hazards are linked to formaldehyde, depending on mode of exposure which includes: weakness, ...

  16. Influence of indoor formaldehyde pollution on respiratory system ...

    African Journals Online (AJOL)

    Background The decoration of interior spaces can lead to dangerous levels of indoor formaldehyde pollution. Exposure to indoor air pollution may be responsible for nearly 2 million deaths per year in developing countries. Objectives To assess the prevalence of indoor formaldehyde pollution caused by decoration and ...

  17. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  18. Development of melamine modified urea formaldehyde resins based o nstrong acidic pH catalyzed urea formaldehyde polymer

    Science.gov (United States)

    Chung-Yun Hse

    2009-01-01

    To upgrade the performance of urea-formaldehyde (UF) resin bonded particleboards, melamine modified urea-formaldehyde (MUF) resins based on strong acidic pH catalyzed UF polymers were investigated. The study was conducted in a series of two experiments: 1) formulation of MUF resins based on a UF polymer catalyzed with strong acidic pH and 2) determination of the...

  19. Quantification of atmospheric formaldehyde by infrared absorption spectroscopy

    Science.gov (United States)

    Hoffnagle, John; Fleck, Derek; Rella, Chris; Kim-Hak, David

    2017-04-01

    Formaldehyde is a toxic, carcinogenic compound that can contaminate ambient air as a result of combustion or outgassing of commercial products such as adhesives used to fabricate plywood and to affix indoor carpeting. Like many small molecules, formaldehyde has an infrared absorption spectrum exhibiting bands of ro-vibrational transitions that are well resolved at low pressure and therefore well suited for optical analysis of formaldehyde concentration. We describe progress in applying cavity ring-down spectroscopy of the 2v5 band (the first overtone of the asymmetric C-H stretch, origin at 1770 nm) to the quantitative analysis of formaldehyde concentration in ambient air. Preliminary results suggest that a sensitivity of 1-2 ppb in a measurement interval of a few seconds, and 0.1-0.2 ppb in a few minutes, should be achievable with a compact, robust, and field-deployable instrument. Finally, we note that recent satellites monitoring snapshots of formaldehyde columns give insights into global formaldehyde production, migration and lifetime. The ability to monitor formaldehyde with a small and portable analyzer has the potential to aid in validation of these snapshots and to provide complementary data to show vertical dispersions with high spatial accuracy.

  20. Formaldehyde: a candidate toxic air contaminant. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frye, B.; Parker, T.

    1988-03-01

    Formaldehyde (HCHO) is a gas widely used in adhesives and resins, textiles, embalming fluids, fungicides, air fresheners, and cosmetics. It is directly emitted into the ambient outdoor air from vehicular and stationary sources, and is also produced in the atmosphere from other substances by photochemical smog processes. The International Agency for Research on Cancer (IARC) has determined that there is sufficient evidence for carcinogenicity of formaldehyde to animals, and limited evidence for carcinogenicity to humans. EPA classifies formaldehyde as a probable human carcinogen with a one in a million risk concentration of 0.08 ppb.

  1. ISOFORMAL: isotopic tracing of formaldehyde sources in housing. Intermediary report

    International Nuclear Information System (INIS)

    2011-01-01

    The authors report an investigation which comprised a sampling and a chemical and isotopic analysis of emissions from the main indoor formaldehyde pollution sources in order to create a exhaustive database. Emissions which are characteristic of motorcar traffic, are also sampled in order to asses their possible contribution in the housing air. This step will be used to develop emission simulations of formaldehyde sources in a laboratory-house in order to validate the isotopic approach as tracing tool for sources of this compound. The report describes the carbon and hydrogen steady isotopes. It presents the sampling procedure, reports the determination of formaldehyde concentrations by high performance liquid chromatography with UV detectors, the use of gas source mass spectrometry, and the analytic development of the isotopic analysis of formaldehyde by gas chromatography combustion isotope ratio mass spectrometry. Outdoor and indoor pollution sources are discussed

  2. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    Science.gov (United States)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  3. Status of iodine in formaldehyde-preserved milk - revisited

    International Nuclear Information System (INIS)

    Montgomery, D.M.; Gibson, J.E.

    1977-01-01

    The results of an investigation into the effect of formaldehyde preservation of raw milk in view of the differences observed by Murthy (J. Dairy Sci.; 45:1066 (1962) and J. Dairy Sci.; 49:1190 (1966)) and Thomas (personal communication. (1976)) are reported. The use of the specific electrode method for iodine analysis of formaldehyde-preserved milk has also been investigated. It was found that the Thomas preservation technique for 4 litre milk samples for 131 I analysis was acceptable, and an aliquot of the formaldehyde-preserved milk can be analyzed for total iodide concentration by the electrode method. Milk samples may also be preserved for stable iodide measurement (without iodide carrier addition) by addition of formaldehyde at 0.5 M concentration. (U.K.)

  4. Formaldehyde cross-linking and structural proteomics: Bridging the gap.

    Science.gov (United States)

    Srinivasa, Savita; Ding, Xuan; Kast, Juergen

    2015-11-01

    Proteins are dynamic entities constantly moving and altering their structures based on their functions and interactions inside and outside the cell. Formaldehyde cross-linking combined with mass spectrometry can accurately capture interactions of these rapidly changing biomolecules while maintaining their physiological surroundings. Even with its numerous established uses in biology and compatibility with mass spectrometry, formaldehyde has not yet been applied in structural proteomics. However, formaldehyde cross-linking is moving toward analyzing tertiary structure, which conventional cross-linkers have already accomplished. The purpose of this review is to describe the potential of formaldehyde cross-linking in structural proteomics by highlighting its applications, characteristics and current status in the field. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Primary Formation Path of Formaldehyde in Hydrothermal Vents

    Science.gov (United States)

    Inaba, Satoshi

    2018-03-01

    Formaldehyde is abundant in the universe and one of the fundamental molecules for life. Hydrothermal vents produce a substantial amount of hydrogen molecules by serpentinization and promote reductive reactions of single carbon compounds. The abundance of formaldehyde is expected to be low due to the high Gibbs free energy in hydrothermal vents. We consider two competing formation pathways of formaldehyde: (1) the reduction of CO by H2 and (2) the reduction of HCOOH by H2 to form a methanediol, followed by the dehydration of the methanediol. We performed a number of quantum chemical simulations to examine the formation of formaldehyde in the gas phase as well as in aqueous solution. The energy barrier is significantly reduced by the catalytic effect of water molecules in aqueous solution and becomes lowest when a water cluster consisted of 5 water molecules catalyzes the reduction. The energy barrier to form a methanediol by the reduction of HCOOH is lower by 17.5 kcal/mol than that to form a formaldehyde by the reduction of CO. Considering the low energy barrier to dehydrate methanediol, the primary pathway to form formaldehyde in hydrothermal vents is concluded to be the reduction of HCOOH by H2, followed by the dehydration of methanediol.

  6. Genotoxicity of formaldehyde: Molecular basis of DNA damage and mutation

    Directory of Open Access Journals (Sweden)

    Masanobu eKawanishi

    2014-09-01

    Full Text Available Formaldehyde is commonly used in the chemical industry and is present in the environment, such as vehicle emissions, some building materials, food and tobacco smoke. It also occurs as a natural product in most organisms, the sources of which include a number of metabolic processes. It causes various acute and chronic adverse effects in humans if they inhale its fumes. Among the chronic effects on human health, we summarize data on genotoxicity and carcinogenicity in this review, and we particularly focus on the molecular mechanisms involved in the formaldehyde mutagenesis. Formaldehyde mainly induces N-hydroxymethyl mono-adducts on guanine, adenine and cytosine, and N-methylene crosslinks between adjacent purines in DNA. These crosslinks are types of DNA damage potentially fatal for cell survival if they are not removed by the nucleotide excision repair pathway. In the previous studies, we showed evidence that formaldehyde causes intra-strand crosslinks between purines in DNA using a unique method (Matsuda et al. Nucleic Acids Res. 26, 1769-1774,1998. Using shuttle vector plasmids, we also showed that formaldehyde as well as acetaldehyde induces tandem base substitutions, mainly at 5’-GG and 5’-GA sequences, which would arise from the intra-strand crosslinks. These mutation features are different from those of other aldehydes such as crotonaldehyde, acrolein, glyoxal and methylglyoxal. These findings provide molecular clues to improve our understanding of the genotoxicity and carcinogenicity of formaldehyde.

  7. Formaldehyde emissions from ULEF- and NAF-bonded commercial hardwood plywood as influenced by temperature and relative humidity

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Michael J. Birkeland; Kyle M. Gonner

    2010-01-01

    It is well documented in the literature that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF) adhesives. This work investigates the effect of temperature and humidity on newer, ultra-low emitting formaldehyde urea formaldehyde (ULEF-UF) and no-added formaldehyde (NAF) adhesives. A...

  8. THE PHOTODISSOCIATION OF FORMALDEHYDE IN COMETS

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Paul D., E-mail: pfeldman@jhu.edu [Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States)

    2015-10-20

    Observations of comets in the 905–1180 Å spectral band made with the Far Ultraviolet Spectroscopic Explorer in 2001 and 2004 show unusual features in the fluorescent emissions of CO and H{sub 2}. These include emission from a non-thermal high-J rotational population of CO and solar Lyα induced fluorescence from excited vibrational levels of H{sub 2}, both of which are attributed to the photodissociation of formaldehyde. In this paper we model the large number of observed H{sub 2} lines and demonstrate the dependence of the pumping on the heliocentric velocity of the comet and the solar line profiles. We also derive the rotational and vibrational populations of H{sub 2} and show that they are consistent with the results of laboratory studies of the photodissociation of H{sub 2}CO. In addition to the principal series of H i and O i, the residual spectrum is found to consist mainly of the Rydberg series of C i multiplets from which we derive the mean carbon column abundance in the coma. Fluorescent emissions from N i and N{sub 2} are also searched for.

  9. Exposure to formaldehyde: a challenge of occupational health significance

    International Nuclear Information System (INIS)

    Kaonga, K.

    2009-01-01

    The use of formaldehyde as the fixative for general microscopic demonstration of tissues in medical laboratory establishments is as significant as the diagnosis of the underlying ailment. Instantaneous human exposure to formaldehyde elicits symptoms that may include watery eyes, headache, inflamed throat and dyspnea. The gaseous chemical is toxic, allergenic and carcinogenic. A study to determine the incidence of human exposure to formaldehyde was carried out at the University Teaching Hospital in Lusaka, Zambia from January to December, 2007. Anonymous questionnaires on various aspects of human exposure to formaldehyde were given to laboratory technical personnel. Exposure to formaldehyde was determined using general consideration model comprising points awarded to participants according to their responses. Five points represented the maximum level of exposure, while one point denoted the minimum encounter. There were 8 incidents of formaldehyde pollution, with five being emissions from 210-litre formalin receptacles whose stoppers were inadvertently left loose overnight, while three involved accidental breakage of Winchester bottles of formalin. A total of 115 people were exposed during the year. Fifteen (13.0 percent) participants scored one point each, while 20 (17.4 percent) participants obtained 2 points each. Thirty-five (30.4 percent) participants got 3 points each, while 30 (26.0 percent) participants received 4 points each. Twenty-five (21.7 percent) participants attained 5 points each. Human exposure to formaldehyde is an issue of occupational health concern. Participants with a score of 3 points or more need regular medical check ups in order to safeguard their health. Programs on effective management of hazardous chemicals are worth setting up.(author)

  10. Research of radiation firmness of transparent melamine-formaldehyde polymers

    International Nuclear Information System (INIS)

    Lebedev, V.V.

    2007-01-01

    Radiation properties of the transparent melamine-formaldehyde polymers offered in quality polymeric basis for making of plastic scintillators are explored in this work. Plastic scintillator is composition, that consists of polymer (polymeric basis) and organic fluorescent addition. Scintillation efficiency and light output are basic properties of plastic scintillators. Firmness to influencing of ionizing radiation is important property of scintillators. From all types of scintillators the plastic are most radiation-proof. Cured melamine-formaldehyde resin and melamine-formaldehyde resin modified by different polyol modifiers was a research object. It is shown that radiation firmness for given types of polymeric material considerably depends on composition of polymer and from technology and temperature condition of its receipt. By the method IR-spectroscopy the structural changes in melamine-formaldehyde polymers under action of irradiation were explored. The maximal falling after the irradiation was marked in intensity of luminescence, which went down to 50% from an initial level. Like the coefficients of admission for all compositions got worse of a to 30-35% level from initial one. Mechanical properties went down on 20-30%. The radiation loss of mass made less than 1% for all polymers. With the increase of temperature of curing firmness rises. Thus, on the basis of the conducted researches radiation firmness for different melamine-formaldehyde polymers is determined and processes what is going on in material under action of radiation are studied. The limited doses of irradiation for each of explored polymers are determined. (authors)

  11. FORMALDEHYDE GAS INACTIVATION OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACE MATERIALS.

    Science.gov (United States)

    Research evaluated the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface material using formaldehyde gas. Spores were dried on seven types of indoor surfaces and exposed to 1100 ppm formaldehyde gas for 10 hr. Fo...

  12. The margin of exposure to formaldehyde in alcoholic beverages.

    Science.gov (United States)

    Monakhova, Yulia B; Jendral, Julien A; Lachenmeier, Dirk W

    2012-06-01

    Formaldehyde has been classified as carcinogenic to humans (WHO IARC group 1). It causes leukaemia and nasopharyngeal cancer, and was described to regularly occur in alcoholic beverages. However, its risk associated with consumption of alcohol has not been systematically studied, so this study will provide the first risk assessment of formaldehyde for consumers of alcoholic beverages.Human dietary intake of formaldehyde via alcoholic beverages in the European Union was estimated based on WHO alcohol consumption data and literature on formaldehyde contents of different beverage groups (beer, wine, spirits, and unrecorded alcohol). The risk assessment was conducted using the margin of exposure (MOE) approach with benchmark doses (BMD) for 10 % effect obtained from dose-response modelling of animal experiments.For tumours in male rats, a BMD of 30 mg kg(-1) body weight per day and a "BMD lower confidence limit" (BMDL) of 23 mg kg(-1) d(-1) were calculated from available long-term animal experiments. The average human exposure to formaldehyde from alcoholic beverages was estimated at 8·10(-5) mg kg(-1) d(-1). Comparing the human exposure with BMDL, the resulting MOE was above 200,000 for average scenarios. Even in the worst-case scenarios, the MOE was never below 10,000, which is considered to be the threshold for public health concerns.The risk assessment shows that the cancer risk from formaldehyde to the alcohol-consuming population is negligible and the priority for risk management (e.g. to reduce the contamination) is very low. The major risk in alcoholic beverages derives from ethanol and acetaldehyde.

  13. Preliminary study: Formaldehyde exposure in laboratories of Sharjah university in UAE

    OpenAIRE

    Ahmed, Hafiz Omer

    2011-01-01

    Objectives : Laboratory technicians, students, and instructors are at high risk, because they deal with chemicals including formaldehyde. Thus, this preliminary study was conducted to measure the concentration of formaldehyde in the laboratories of the University of Sharjah in UAE. Materials and Methods: Thirty-two air samples were collected and analyzed for formaldehyde using National Institute for Occupational Safety and Health (NIOSH) method 3500. In this method, formaldehyde reacts with c...

  14. Pressure dependent isotopic fractionation in the photolysis of formaldehyde-d2

    DEFF Research Database (Denmark)

    Nilsson, E.J.K.; Schmidt, Johan Albrecht; Johnson, Matthew Stanley

    2014-01-01

    role in the observed pressure dependent photolytic fractionation of deuterium. The model shows that part of the fractionation is a result of competition between the isotopologue dependent rates of unimolecular dissociation and collisional relaxation. We suggest that the remaining fractionation is due......The isotope effects in formaldehyde photolysis are the key link between the δD of methane emissions and the δD of atmospheric in situ hydrogen production. A few recent studies have suggested that a pressure dependence in the isotopic fractionation can partly explain enrichment of deuterium...... with altitude in the atmosphere. The mechanism and the extent of this pressure dependency is, however, not adequately described. In the present work D2CO and H2CO were photolyzed in a static reaction chamber at bath gas pressures of 50, 200, 400, 600 and 1000 mbar; these experiments compliment and extend our...

  15. Preparation and characterization of phloroglucinol-formaldehyde aerogel

    International Nuclear Information System (INIS)

    Huang Changgang; China Academy of Engineering Physics, Mianyang; Tang Yongjian; Wang Chaoyang; Yan Hongmei

    2006-01-01

    Phloroglucinol-formaldehyde (PF) aerogels and carbonized PF (CPF) aerogels were prepared from Phloroglucinol (P) and Formaldehyde (F) by sol-gel, solvent exchanging, supercritical drying and carbonization processes. The aerogel has a large specific surface area, continuous nano-network and porous structure. The density and mean porosity radius will enlarge after being carbonized, while the specific surface area will be influenced little. The micro-structure and density of aerogel are controlled by concentration of total reactants and catalyzer, respectively. Aerogels with different micro-structure and different density fit for ICF targets can be prepared by optimizing synthesis conditions. (authors)

  16. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Directory of Open Access Journals (Sweden)

    Schwemmer G.

    2016-01-01

    Full Text Available We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  17. Relationship between formaldehyde and quaternium-15 contact allergy. Influence of strength of patch test reactions

    NARCIS (Netherlands)

    de Groot, Anton C.; Blok, Janine; Coenraads, Pieter-Jan

    2010-01-01

    Objectives: To test our hypothesis that patients with stronger patch test reactions to formaldehyde are more likely to react to quaternium-15, attesting to the aetiological role for formaldehyde in such co-reactivity. Methods: Retrospective analysis of all patients patch tested with formaldehyde and

  18. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea-formaldehyde resins in molded articles. 177... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact surface...

  19. Effect of formaldehyde on the upper respiratory tract _ormal flora of ...

    African Journals Online (AJOL)

    Background: Formaldehyde is a chemical that is used to fix a tissue after death or removal from the body to prevent autolysis and putrefaction. Exposure to formaldehyde can occur as a result of occupation. Objective: To determine the effect of the formaldehyde on the throat and nasal flora of upper respiratory tract of rabbits ...

  20. 40 CFR 721.3810 - Formaldehyde, polymers with substituted phenols (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymers with... New Uses for Specific Chemical Substances § 721.3810 Formaldehyde, polymers with substituted phenols... identified generically as Formaldehyde, polymers with substituted phenols (PMN P-99-0558) is subject to...

  1. Preparation of carbon dioxide adsorbents from the chemical activation of urea-formaldehyde and melamine-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Drage; A. Arenillas; K.M. Smith; C. Pevida; S. Piippo; C.E. Snape [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

    2007-01-15

    Adsorption is considered to be one of the more promising technologies for the capture of CO{sub 2} from flue gases. In general, nitrogen enrichment is reported to be effective in enhancing the specific adsorbent-adsorbate interaction for CO{sub 2}. Nitrogen enriched carbons were produced from urea-formaldehyde and melamine-formaldehyde resins polymerised in the presence of K{sub 2}CO{sub 3} as a chemical activation agent, with activation undertaken over a range of temperatures. CO{sub 2} adsorption capacity was determined to be dependent upon both textural properties and more importantly nitrogen functionality. Adsorbents capable of capturing above 8 wt.% CO{sub 2} at 25{sup o}C were produced from the chemical activation of urea-formaldehyde resin at 500{sup o}C. Chemical activation seems to produce more effective adsorbents than CO{sub 2} activation. 29 refs., 4 figs., 3 tabs.

  2. Contact allergic dermatitis from melamine formaldehyde resins in a patient with a negative patch-test reaction to formaldehyde.

    Science.gov (United States)

    García Gavin, Juan; Loureiro Martinez, Manuel; Fernandez-Redondo, Virginia; Seoane, Maria-José; Toribio, Jaime

    2008-01-01

    Melamine paper is a basic material used in the furniture industry for home and office interiors. Contact allergic dermatitis from melamine formaldehyde resins (MFRs) should be considered in patients who work on melamine paper impregnation lines. We report a case of a 28-year-old female plywood worker who developed eczema on the dorsal side of her hands and wrists after 2 years of working on the melamine paper impregnation line. She had a relevant positive patch-test reaction to MFR, with a negative reaction to formaldehyde. Contact dermatitis due to MFR is not common, and it is usually related to products that are not fully cured or to close contact with intermediate products on the assembly line. Formaldehyde release from MFR can explain most of the positive responses. To our knowledge, this is the first report of MFR contact allergic dermatitis in a worker on a melamine paper impregnation line.

  3. Sol-gel based sensor for selective formaldehyde determination

    Energy Technology Data Exchange (ETDEWEB)

    Bunkoed, Opas [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Davis, Frank [Cranfield Health, Cranfield University, Bedford MK43 0AL (United Kingdom); Kanatharana, Proespichaya, E-mail: proespichaya.K@psu.ac.th [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thavarungkul, Panote [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Higson, Seamus P.J., E-mail: s.p.j.higson@cranfield.ac.uk [Cranfield Health, Cranfield University, Bedford MK43 0AL (United Kingdom)

    2010-02-05

    We report the development of transparent sol-gels with entrapped sensitive and selective reagents for the detection of formaldehyde. The sampling method is based on the adsorption of formaldehyde from the air and reaction with {beta}-diketones (for example acetylacetone) in a sol-gel matrix to produce a yellow product, lutidine, which was detected directly. The proposed method does not require preparation of samples prior to analysis and allows both screening by visual detection and quantitative measurement by simple spectrophotometry. The detection limit of 0.03 ppmv formaldehyde is reported which is lower than the maximum exposure concentrations recommended by both the World Health Organisation (WHO) and the Occupational Safety and Health Administration (OSHA). This sampling method was found to give good reproducibility, the relative standard deviation at 0.2 and 1 ppmv being 6.3% and 4.6%, respectively. Other carbonyl compounds i.e. acetaldehyde, benzaldehyde, acetone and butanone do not interfere with this analytical approach. Results are provided for the determination of formaldehyde in indoor air.

  4. Sol-gel based sensor for selective formaldehyde determination

    International Nuclear Information System (INIS)

    Bunkoed, Opas; Davis, Frank; Kanatharana, Proespichaya; Thavarungkul, Panote; Higson, Seamus P.J.

    2010-01-01

    We report the development of transparent sol-gels with entrapped sensitive and selective reagents for the detection of formaldehyde. The sampling method is based on the adsorption of formaldehyde from the air and reaction with β-diketones (for example acetylacetone) in a sol-gel matrix to produce a yellow product, lutidine, which was detected directly. The proposed method does not require preparation of samples prior to analysis and allows both screening by visual detection and quantitative measurement by simple spectrophotometry. The detection limit of 0.03 ppmv formaldehyde is reported which is lower than the maximum exposure concentrations recommended by both the World Health Organisation (WHO) and the Occupational Safety and Health Administration (OSHA). This sampling method was found to give good reproducibility, the relative standard deviation at 0.2 and 1 ppmv being 6.3% and 4.6%, respectively. Other carbonyl compounds i.e. acetaldehyde, benzaldehyde, acetone and butanone do not interfere with this analytical approach. Results are provided for the determination of formaldehyde in indoor air.

  5. Influence of indoor formaldehyde pollution on respiratory system ...

    African Journals Online (AJOL)

    Some adults surveyed complained of common respiratory system disorders, including coughing (11.8%), nasal irritation (39.2%), Heterosmia (14.51%), and throat irritation (25.27%); 12% of children suffered from asthma. The analysis identified formaldehyde pollution and ventilation frequency as risk factors for respiratory ...

  6. Studies of Deactivation of Methanol to Formaldehyde Selective Oxidation Catalyst

    DEFF Research Database (Denmark)

    Raun, Kristian Viegaard; Schumann, Max; Høj, Martin

    This work presents a study of the deactivation behavior of Fe-Mo oxide catalyst during selective oxidation of methanol to formaldehyde in a period of 5 days. The structural changes in the catalyst have been investigated in situ for the initial 10 h by Raman spectroscopy, and the structure after 5...

  7. Supramolecular nano-sniffers for ultrasensitive detection of formaldehyde.

    Science.gov (United States)

    Akshath, Uchangi Satyaprasad; Bhatt, Praveena

    2018-02-15

    Supramolecular nanoparticle hybrids for biosensing of analytes have been a major focus due to their tunable optical and surface properties. Quantum dots-Gold nanoparticle (QDs-GNP) based FRET probes involving turn on/off principles have gained immense interest due to their specificity and sensitivity. Recent focus is on applying these supramolecular hybrids for enzyme operated biosensors that can specifically turn-on fluorescence induced by co-factor or product formed from enzymatic reaction. The present study focuses on locking and unlocking the interaction between QD-GNP pair leading to differential fluorescent properties. Cationic GNPs efficiently quenched the anionic QD fluorescence by forming nanoparticle hybrid. Quenching interaction between QD-GNP pair was unlocked by NADH leading to QD fluorescence turn-on. This phenomenon was applied for the successful detection of formaldehyde using NAD + dependent formaldehyde dehydrogenase. The proposed nano-sniffer could successfully detect formaldehyde from 0.001 to 100000ng/mL (R 2 = 0.9339) by the turn off-turn on principle. It could also detect formaldehyde in fruit juice and wine samples indicating its stability and sensitivity in real samples. The proposed nanoprobe can have wide applications in developing enzyme biosensors in future. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. A short review on photocatalytic degradation of formaldehyde

    NARCIS (Netherlands)

    Tasbihi, M.; Bendyna, J.K.; Notten, P.H.L.; Hintzen, H.T.J.M.

    2015-01-01

    Nowadays, it is a great challenge to eliminate toxic and harmful organic pollutants from air and water. This paper reviews the role of TiO2 as a photocatalyst, light source and photoreactor in the particular case of removal of formaldehyde using the photocatalytic reaction by titanium dioxide (TiO2

  9. Effect of cultivar and formaldehyde treatment of barley grain on ...

    African Journals Online (AJOL)

    ... but increased the time (h) to produce 50% of A and reduced the time (h) to produce 95% of A. The reduction in gas production ranged from 33.3 to 51 mL/g OM with 6 h incubation showing the highest decrease in gas production. It is concluded that formaldehyde treatment may provide an opportunity to manipulate the site ...

  10. Electrodeposition of gold from formaldehyde-sulfite baths: bath stability and deposits characterization

    Directory of Open Access Journals (Sweden)

    Juliana L. Cardoso

    2011-01-01

    Full Text Available It was investigated Au(I-sulfite baths containing formaldehyde. As a result, high stability was achieved for baths containing formaldehyde concentration close to 10 mL L-1 with a lifetime superior to 600 days. On the other hand, cyclic voltammograms indicated that the increase of formaldehyde concentration in the bath promotes decreasing of the maximum cathodic current, so that, if the formaldehyde concentration is high, the surface areal concentration of gold will be low. Also, the lowest surface roughness was obtained for 10 mL L-1 of formaldehyde.

  11. Formaldehyde as an antiseptic in the production of alcohol from molasses

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, V J; Stros, F

    1962-01-01

    The effect of formaldehyde as an antiseptic for the noncontaminated alcohol fermentation of molasses was examined with five different yeasts mash batches containing formaldehyde 0.01%. Following 24 hour cultivation, increase in the activity of formaldehyde-inoculated mash was lowered by 47%; the formaldehyde decreased the alcohol fermentation and lessened the rate of fermentation of sugar by 20% in noncontaminated mash. The decrease in the fermentation rate was also observed during the entire course of fermentation. On the other hand, formaldehyde addition to molasses contaminated with lactic acid bacteria accelerated the fermentation rate.

  12. Formaldehyde as an antiseptic in the production of alcohol from molasses

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, M; Vernerova, J; Stros, F

    1962-01-01

    The effect of formaldehyde as an antiseptic for the noncontaminated alcohol fermentation of molasses was examined with five different yeast-mash batches containing formaldehyde 0.01%. Following 24 hour cultivation, increase in the activity of formaldehyde-inoculated mash was lowered by 47%; the formaldehyde decreased the alcohol fermentation and lessened the rate of fermentation of sugar by 20% in noncontaminated mash. The decrease in the fermentation rate was also observed during the entire course of fermentation. On the other hand, formaldehyde addition to molasses contaminated with lactic acid bacteria accelerated the fermentation rate by inhibiting the bacterial growth; the degree of retardation due to the contamination was greater than that due to the antiseptic. The view that formaldehyde decreased the effectiveness of growth substances by binding the amino acid present in mash mixtures could not be confirmed; it was believed that formaldehyde was absorbed by yeast cells even through the entities thus destroyed could not be differentiated from living cells by methylene blue. Higher resistance of yeast cultures to formaldehyde was obtained by repeated transfers of the yeast in media containing formaldehyde. It was concluded that formaldehyde added to contaminated molasses inhibited the further growth of the contamination, increased yield of ethanol on the basis of the sugar, and simultaneously decreased the net yield of ethanol in contrast to the yield from noncontaminated mashes in the absence of formaldehyde.

  13. Angle-resolved photoelectron spectroscopy of formaldehyde and methanol

    Science.gov (United States)

    Keller, P. R.; Taylor, J. W.; Grimm, F. A.; Carlson, Thomas A.

    1984-10-01

    Angle-resolved photoelectron spectroscopy was employed to obtain the angular distribution parameter, β, for the valence orbitals (IP < 21.1 eV) of formaldehyde and methanol over the 10-30 eV photon energy range using dispersed polarized synchrotron radiation as the excitation source. It was found that the energy dependence of β in the photoelectron energy range between 2 and 10 eV can be related to the molecular-orbital type from which ionization occurs. This generalized energy behavior is discussed with regard to earlier energy-dependence studies on molecules of different orbital character. Evidence is presented for the presence of resonance photoionization phenomena in formaldehyde in agreement with theoretical cross-section calculations.

  14. persimmon tannin-formaldehyde gel decontamination of dilute aqueous solutions

    International Nuclear Information System (INIS)

    Omar, H.A.

    2009-01-01

    in the present work, the extracted juice of unripe astringent persimmon fruit, designated as (kakishibu) was found to have an extremely high affinity for uranium ion. to develop efficient adsorbent for uranium ion the juice was immobilized in formaldehyde. the removal of uranium ion onto the formed gel was found to be affected by several factors such as, concentration of formaldehyde in gel, equilibration time, solution ph, concentration of uranium ion, mass of adsorbent, presence of some cations and anions . the sorption isotherm was discussed in the light of Freundlich and Langmuir models. from Freundlich equation, the exponent 1/n was found in the range of 1>1/n 0 , δS 0 and δG 0 were calculated . the capacity of adsorbent was also determined by column technique and found to 20.20 mg/g

  15. Enzymatic synthesis of C-11 formaldehyde: concise communication

    International Nuclear Information System (INIS)

    Slegers, G.; Lambrecht, R.H.D.; Vandewalle, T.; Meulewaeter, L.; Vandecasteele, C.

    1984-01-01

    An enzymatic synthesis of C-11 formaldehyde from C-11 methanol is presented, with immobilized alcohol oxidase and catalase: a rapid, simple procedure, with a high and reproducible yield. Carbon-11 methanol is oxidized to C-11 formaldehyde by passage over a column on which the enzymes alcohol oxidase and catalase are immobilized. The catalase increases reaction velocity by recycling the oxygen, and prevents destruction of the alcohol oxidase by eliminating the excess of hydrogen peroxide. The yield of the enzyme-catalyzed oxidation was 80-95%. A specific activity of 400-450 mCi/μmole was obtained at EOB + 20 min. Various immobilization techniques and the optimal reaction conditions of the immobilized enzymes are investigated

  16. Simple, rapid method for the preparation of isotopically labeled formaldehyde

    Science.gov (United States)

    Hooker, Jacob Matthew [Port Jefferson, NY; Schonberger, Matthias [Mains, DE; Schieferstein, Hanno [Aabergen, DE; Fowler, Joanna S [Bellport, NY

    2011-10-04

    Isotopically labeled formaldehyde (*C.sup..sctn.H.sub.2O) is prepared from labeled methyl iodide (*C.sup..sctn.H.sub.3I) by reaction with an oxygen nucleophile having a pendant leaving group. The mild and efficient reaction conditions result in good yields of *C.sup..sctn.H.sub.2O with little or no *C isotopic dilution. The simple, efficient production of .sup.11CH.sub.2O is described. The use of the .sup.11CH.sub.2O for the formation of positron emission tomography tracer compounds is described. The reaction can be incorporated into automated equipment available to radiochemistry laboratories. The isotopically labeled formaldehyde can be used in a variety of reactions to provide radiotracer compounds for imaging studies as well as for scintillation counting and autoradiography.

  17. Investigations on potential co-mutagenic effects of formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Speit, Günter, E-mail: guenter.speit@uni-ulm.de; Linsenmeyer, Regina; Duong, Giang; Bausinger, Julia

    2014-02-15

    Highlights: • A549 cells were exposed to formaldehyde in combination with various mutagens. • Formaldehyde did not affect the induction and removal of DNA damage (comet assay). • Formaldehyde did not affect the induction of micronuclei by the mutagens tested. • The expression of the O{sup 6}-methylguanine-DNA methyltransferase was not affected. - Abstract: The genotoxicity and mutagenicity of formaldehyde (FA) has been well-characterized during the last years. Besides its known direct DNA-damaging and mutagenic activity in sufficiently exposed cells, FA at low concentrations might also enhance the mutagenic and carcinogenic effects of other environmental mutagens by interfering with the repair of DNA lesions induced by these mutagens. To further assess potential co-mutagenic effects of FA, we exposed A549 human lung cells to FA in combination with various mutagens and measured the induction and removal of DNA damage by the comet assay and the production of chromosomal mutations by the cytokinesis-block micronucleus assay (CBMN assay). The mutagens tested were ionizing radiation (IR), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), N-nitroso-N-methylurea (methyl nitrosourea; MNU) and methyl methanesulfonate (MMS). FA (10–75 μM) did not enhance the genotoxic and mutagenic activity of these mutagens under the test conditions applied. FA alone and in combination with MNU or MMS did not affect the expression (mRNA level) of the gene of the O{sup 6}-methylguanine-DNA methyltransferase (MGMT) in A549 cells. The results of these experiments do not support the assumption that low FA concentrations might interfere with the repair of DNA damage induced by other mutagens.

  18. Low-density carbonized resorcinol-formaldehyde foams

    International Nuclear Information System (INIS)

    Kong, F.M.; Buckley, S.R.; Giles, C.L. Jr.; Haendler, B.L.; Hair, L.M.; Letts, S.A.; Overturf, G.E. III; Price, C.W.; Cook, R.C.

    1991-01-01

    This report documents research and development on resorcinol- formaldehyde-based foam materials conducted between 1986 and June 1990, when the effort was discontinued. The foams discussed are resorcinol-formaldehyde (RF) foam, carbonized RF (CRF) foam, and two composite foams, a polystyrene/RF (PS/RF) foam and its carbonized derivative (CPR). The RF foams are synthesized by the polycondensation of resorcinol with formaldehyde in a slightly basic solution. Their structure and density depend strongly on the concentration of the sodium carbonate catalyst. The have an interconnected bead structure similar to that of silica aerogels; bead sizes range from 30 to 130 Angstrom, and cell sizes are less than 0.1 μm. We have achieved densities of 16 to 200 mg/cm 3 . The RF foams can be pyrolyzed in an inert atmosphere to form a vitreous carbon foam (CRF), which has a similar microstructure but much higher mechanical strength. The PS/RF foams are obtained by filling the 2- to 3-μm cells of PS foam (a low-density hydrocarbon foam we have developed) with RF. The resultant foams have the outstanding handling and machinability of the PS foam matrix and the small cell size of RF. Pyrolyzing PS/RF foams causes depolymerization and loss of the PS; the resulting CPR foams have a structure similar to the PS foams in which CRF both replicates and fills the PS cells

  19. Formaldehyde and acetaldehyde emissions from residential wood combustion in Portugal

    Science.gov (United States)

    Cerqueira, Mário; Gomes, Luís; Tarelho, Luís; Pio, Casimiro

    2013-06-01

    A series of experiments were conducted to characterize formaldehyde and acetaldehyde emissions from residential combustion of common wood species growing in Portugal. Five types of wood were investigated: maritime pine (Pinus pinaster), eucalyptus (Eucalyptus globulus), cork oak (Quercus suber), holm oak (Quercus rotundifolia) and pyrenean oak (Quercus pyrenaica). Laboratory experiments were performed with a typical wood stove used for domestic heating in Portugal and operating under realistic home conditions. Aldehydes were sampled from diluted combustion flue gas using silica cartridges coated with 2,4-dinitrophenylhydrazine and analyzed by high performance liquid chromatography with diode array detection. The average formaldehyde to acetaldehyde concentration ratio (molar basis) in the stove flue gas was in the range of 2.1-2.9. Among the tested wood types, pyrenean oak produced the highest emissions for both formaldehyde and acetaldehyde: 1772 ± 649 and 1110 ± 454 mg kg-1 biomass burned (dry basis), respectively. By contrast, maritime pine produced the lowest emissions: 653 ± 151 and 371 ± 162 mg kg-1 biomass (dry basis) burned, respectively. Aldehydes were sampled separately during distinct periods of the holm oak wood combustion cycles. Significant variations in the flue gas concentrations were found, with higher values measured during the devolatilization stage than in the flaming and smoldering stages.

  20. Formaldehyde, methanol and hydrocarbon emissions from methanol-fueled cars

    International Nuclear Information System (INIS)

    Williams, R.L.; Lipari, F.; Potter, R.A.

    1990-01-01

    Exhaust and evaporative emissions tests were conducted on several methanol- and gasoline-fueled vehicles. Separate samples for chromatographic analysis of formaldehyde, methanol, and individual hydrocarbons were collected in each of the three phases of the driving cycle and in each of the two portions of the evaporative emissions test. One vehicle, equipped with an experimental variable-fuel engine, was tested using methanol/gasoline fuel mixtures of 100, 85, 50, 15, and 0 percent methanol. Combustion-generated hydrocarbons were lowest using methanol fuel, and increased several-fold as the gasoline fraction was increased. Gasoline components in the exhaust increased from zero as the gasoline fraction of the fuel was increased. On the other hand, formaldehyde emissions were several times higher using methanol fuel than they were using gasoline. A dedicated methanol car and the variable-fuel car gave similar emissions patterns when they both were tested using methanol fuel. The organic-carbon composition of the exhaust was 85-90 percent methanol, 5-7 percent formaldehyde, and 3-9 percent hydrocarbons. Several cars that were tested using gasoline emitted similar distributions of hydrocarbons, even through the vehicles represented a broad range of current and developmental engine families and emissions control systems

  1. Fast fluorometric flow injection analysis of formaldehyde in atmospheric water

    Energy Technology Data Exchange (ETDEWEB)

    Dong, S.; Dasgupta, P.K.

    1987-06-01

    Formaldehyde can be determined in aqueous solution at a rate of 45 samples/h with a small sample requirement (100 ..mu..L). The fluorescence of 3,5-diacetyl-1,4-dihydrolutidine formed upon reaction of formaldehyde with ammonium acetate and 2,4-pentanedione (25 s, 95 /sup 0/C) is monitored with a filter fluorometer. The detection limit is 0.1 ..mu..M (3 ..mu..g/L) or 10 pmol of HCHO. The response is linear up to 3.3 ..mu..M (100 ..mu..g/L), the departure from linearity at 0.33 mM is 21%, but high levels are satisfactorily determined with a second-order calibration equation. Interference from S(IV) has been investigated in detail and completely eliminated by addition of H/sub 2/O/sub 2/ before rendering the sample alkaline. There are no effects from commonly occurring metal ions and anions; the method is very selective to formaldehyde compared to other carbonyl compounds. A S(IV)-containing preservative has been formulated for the stabilization of low concentrations of HCHO. Results are presented for fogwater samples. 8 figures, 41 references.

  2. Urea-formaldehyde resins: production, application, and testing

    Science.gov (United States)

    Nuryawan, A.; Risnasari, I.; Sucipto, T.; Heri Iswanto, A.; Rosmala Dewi, R.

    2017-07-01

    Urea-formaldehyde (UF) resin, one of the most important formaldehyde resin adhesives, is a polymeric condensation product of formaldehyde with urea, and being widely used for the manufacture of wood-based composite panels, such as plywood, particleboard, and fiberboard. In spite of its benefits such as fast curing, good performance in the panels (colorless), and lower cost; formaldehyde emission (FE) originated from either UF resin itself or composite products bonded by UF resins is considered a critical drawback as it affects human health particularly in indoor environment. In order to reduce the FE, lowering formaldehyde/urea (F/U) mole ratio in the synthesis of the UF resin was done. In this study, synthesis of UF resins was carried out following the conventional alkaline-acid two-step reaction with a second addition of urea, resulting in F/U mole ratio around 1.0, namely 0.95; 1.05, and 1.15. The UF resins produced were used as binder for particleboard making. The board was manufactured in the laboratory using shaving type particle of Gmelina wood, 8% UF resin based on oven dry particle, and 1% NH4Cl (20%wt) as hardener for the resin. The target of the thickness was 10 mm and the dimension was 25 cm x 25 cm. The resulted particleboard then was evaluated the physical and the mechanical properties by Japanese Industrial Standard (JIS) A 5908 (2003). Further, the resulted particleboard also was used for the mice cage’s wall in order to mimic the real living environment. After four weeks exposure in the cages, the mice then were evaluated their mucous organs as well as their blood. The experiment results were as follows: 1) It was possible to synthesis UF resins with low F/U mole ratio; 2) However, the particleboard bonded UF resins with low F/U mole ratio showed poor properties, particularly on the thickness swelling and modulus of elasticity; 3) There was no significant differences among the mucous organs of the mice after a month exposure FE originated from

  3. Melamine-bridged alkyl resorcinol modified urea - formaldehyde resin for bonding hardwood plywood

    Science.gov (United States)

    Chung-Yun Hse; Mitsuo Higuchi

    2010-01-01

    A powdery product was obtained by the reaction of methylolated melamine with alkyl resorcinols to form melamine-bridged alkyl resorcinols (MARs). The effects of the addition of this powder on the bonding strength and formaldehyde emission of urea–formaldehyde (UF) resins were investigated. Three types of UF resins with a formaldehyde/urea molar ratio of 1.3 synthesized...

  4. A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

    Energy Technology Data Exchange (ETDEWEB)

    Parthasarathy, Srinandini; Spears, Michael; Maddalena, Randy L.; Russell, Marion L; Apte, Michael G.

    2010-10-01

    The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios.

  5. Fiber-Based Adsorbents Tailored for PLSS Ammonia and Formaldehyde Removal, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of advanced lightweight Trace Contaminant Control (TCC) filters plays an important role in removing ammonia and formaldehyde contaminants?both those...

  6. Characterization and Application of Urea-Formaldehyde-Furfural Co-condensed Resins as Wood Adhesives

    Directory of Open Access Journals (Sweden)

    Jizhi Zhang

    2014-08-01

    Full Text Available Furfural, as an organic compound derived from biomass materials, was used to partially substitute for formaldehyde in the synthesis of UF resin. Urea-formaldehyde-furfural co-condensed (UFFR resins with different substitute ratios of furfural to formaldehyde (FR/F were prepared. The effects of the FR/F substitute ratio on the performances of UFFR resins were investigated. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS and Fourier transform infrared spectroscopy (FT-IR were applied to characterize the chemical structures of UFFR resins. Plywood bonded by these resins was manufactured, and its bond strength and formaldehyde emission were measured. The results showed that the substitution of furfural in place of formaldehyde could reduce the free formaldehyde content effectively at the expense of prolongation of the curing time. The spectra of MALDI-TOF and FTIR confirmed the co-condensation of urea-formaldehyde-furfural both in uncured and cured resins. Plywood prepared under optimized parameters could yield high bond strength and low formaldehyde emission, which were 0.84 MPa and 0.23 ppm, respectively. The optimized parameters were as follows: a FR/F substitute ratio of 1/3; 1% (NH42S2O8 as the curing agent; and a hot pressing temperature of 130 °C. Hence, it is feasible to substitute partially formaldehyde by furfural to prepare UFFR resins as wood adhesives for plywood.

  7. Inactivation kinetics of formaldehyde on N-acetyl-β-D-glucosaminidase from Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Zhang, Wei-Ni; Bai, Ding-Ping; Lin, Xin-Yu; Chen, Qing-Xi; Huang, Xiao-Hong; Huang, Yi-Fan

    2014-04-01

    Formaldehyde is a widely used sanitizer in aquaculture in China, while the appropriate concentration is not available to be used effectively and without damage to tilapia much less to its reproductive function. N-acetyl-β-D-glucosaminidase (EC 3.2.1.52, NAGase), hydrolyzing the oligomers of N-acetyl-β-D-glucosamine into monomer, is proved to be correlated with reproduction of male animals. In this paper, NAGase from spermary of tilapia was chosen as the material to study the effects of formaldehyde on its activity in order to further investigate the effects of formaldehyde use on tilapia reproduction. The results showed the relationship between the residual enzyme activity and the concentration of formaldehyde was concentration dependent, and the IC50 value was estimated to be 3.2 ± 0.1 %. Appropriate concentration of formaldehyde leaded to competitive reversible inhibition on tilapia NAGase. Moreover, formaldehyde could reduce the thermal and pH stability of the enzyme. The inactivation kinetics of formaldehyde on the enzyme was studied using the kinetic method of substrate reaction. The inactivation model was setup, and the rate constants were determined. The results showed that the inactivation of formaldehyde on tilapia NAGase was a slow, reversible reaction with partially residual activity. The results will give some basis to determine the concentration of formaldehyde used in tilapia culture.

  8. NMR studies of proton exchange kinetics in aqueous formaldehyde solutions.

    Science.gov (United States)

    Rivlin, Michal; Eliav, Uzi; Navon, Gil

    2014-05-01

    Aqueous solutions of formaldehyde, formalin, are commonly used for tissue fixation and preservation. Treatment with formalin is known to shorten the tissue transverse relaxation time T2. Part of this shortening is due to the effect of formalin on the water T2. In the present work we show that the shortening of water T2 is a result of proton exchange between water and the major constituent of aqueous solutions of formaldehyde, methylene glycol. We report the observation of the signal of the hydroxyl protons of methylene glycol at 2ppm to high frequency of the water signal that can be seen at low temperatures and at pH range of 6.0±1.5 and, at conditions where it cannot be observed by the single pulse experiment, it can be detected indirectly through the water signal by the chemical exchange saturation transfer (CEST) experiment. The above finding made it possible to obtain the exchange rate between the hydroxyl protons of the methylene glycol and water in aqueous formaldehyde solutions, either using the dispersion of the spin-lattice relaxation rate in the rotating frame (1/T1ρ) or, at the slow exchange regime, from the line width hydroxyl protons of methylene glycol. The exchange rate was ∼10(4)s(-1) at pH 7.4 and 37°C, the activation energy, 50.2kJ/mol and its pH dependence at 1.1°C was fitted to: k (s(-1))=520+6.5×10(7)[H(+)]+3.0×10(9)[OH(-)]. Copyright © 2014. Published by Elsevier Inc.

  9. Rotational spectrum of formaldehyde reinvestigated using a photomixing THz synthesizer

    Science.gov (United States)

    Eliet, Sophie; Cuisset, Arnaud; Guinet, Mickaël; Hindle, Francis; Mouret, Gaël; Bocquet, Robin; Demaison, Jean

    2012-09-01

    Approximately 60 pure rotational frequency transitions of formaldehyde in its ground state have been measured with sub-MHz uncertainty in the 0.7-1.8 THz frequency range using a photomixing THz synthesizer locked onto a frequency comb. The frequencies associated with previous submillimeter and infrared data have been included in a fit providing a new set of improved molecular parameters. The assignment of each line was checked using the usual statistical diagnostics. Finally, the ability of the continuous-wave spectrometer coupled to a multipass-cell to measure THz rotational transitions of H2CO in the 31, 41 and 61 vibrational states was demonstrated.

  10. Syntheses with isotopically labelled carbon. Methyl iodide, formaldehyde and cyanide

    International Nuclear Information System (INIS)

    Finn, R.D.; Boothe, T.E.; Vora, M.M.; Hildner, J.C.; Emran, A.M.; Kothari, P.J.

    1984-01-01

    Many of the uniquely labelled synthetic precursors currently employed in the design of sophisticated radiolabelled compounds have their origins in the field of hot atom chemistry. Particularly, the development during the past few years of automated, on-line synthetic procedures which combine the nuclear reaction, hot atom and classical chemistry, and rapid purification methods has allowed the incorporation of useful radionuclides into suitable compounds of chemical and biochemical interest. The application of isotopically labelled methyl iodide, formaldehyde, and cyanide anion as synthetic intermediates in research involving human physiology and nuclear medicine, as well as their contributions to other scientific methodology, is reviewed. (author)

  11. 40 CFR 721.10189 - Fatty acids, tall-oil, reaction products with (butoxymethyl) oxirane formaldehyde-phenol polymer...

    Science.gov (United States)

    2010-07-01

    ... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine...-phenol polymer glycidyl ether, morpholinepropanamine, propylene glycol diamine and aliphatic polyamine, N... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine...

  12. Chemosorption sampling and analysis of formaldehyde in air. Influence on recovery during the simultaneous sampling of formaldehyde, phenol, furfural and furfuryl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, K.; Hallgren, C.; Levin, J.O.; Nilsson, C.A.

    1981-12-01

    A method based on trapping formaldehyde on a 2,4-dinitrodinitrophenylhydrazine-coated porous polymer (Amberlite XAD-2) was evaluated for air sampling in occupational environments. The aldehyde is converted to its 2,4-dinitrophenylhydrazone on the adsorbent. The influence of some organic compounds which often occur together with formaldehyde-furfural, phenol and furfuryl alcohol--was studied. The results show that the method allows the sampling of formaldehyde in the range 0.01--1.0 mg/m3 of air, based on a 3-1 (15 min) sample and a coating of 1%. Furfural, phenol, and furfuryl alcohol do not interfere and may be conveniently sampled at the same time. Formaldehyde and furfural hydrazones were analyzed by high-performance liquid chromatography, phenol and furfuryl alcohol by gas chromatography.

  13. Formaldehyde emission from particleboard and plywood paneling : measurement, mechanism, and product standards

    Science.gov (United States)

    George E. Myers

    1983-01-01

    A number of commercial panel products, primarily particleboard and hardwood plywood, were tested for their formaldehyde emission behavior using desiccator, perforator, and dynamic chamber methods. The results were analyzed in terms of the source of formaldehyde observed in the tests (free vs. hydrolytically produced) and the potential utility of the testa as product...

  14. Effect of ventilation rate and board loading on formaldehyde concentration : a critical review of the literature

    Science.gov (United States)

    George E. Myers

    1984-01-01

    A critical literature review has been carried out on the influence of ventilation rate (N, hr.-1) and board loading (L, m2/m3) on steady state formaldehyde concentrations (Cs, ppm) resulting from particleboard and plywood emissions. Large differences exist among boards in the extent to which their formaldehyde concentrations change with N or L in laboratory chambers....

  15. Emission of formaldehyde by particleboard : effect of ventilation rate and loading on air-contamination levels

    Science.gov (United States)

    George E. Myers; Muneo Nagaoka

    1981-01-01

    Dynamic tests for determining the formaldehyde emission behavior of UF-bonded boards involve the measurement of formaldehyde concentration in the air within a vessel which contains a specified board loading L (m2 of board area per m3 of vessel free volume) and is being ventilated at a specified air exchange rate N (hr.-1). Such tests constitute a primary...

  16. 40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

    Science.gov (United States)

    2010-07-01

    ... Insulation Resins by Hydroxylamine Hydrochloride B Appendix B to Subpart NNN of Part 63 Protection of...—Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride 1. Scope This method was... hydrochloric acid that is liberated when hydroxylamine hydrochloride reacts with formaldehyde to form...

  17. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

  18. "Greener" hybrid adhesives composed of urea formaldehyde resin and cottonseed meal for wood based composites

    Science.gov (United States)

    Urea formaldehyde (UF) resins are one of the most widely used adhesives in wood based composites. The major concerns of the resin utilization are free formaldehyde release and poor water resistance. As a renewable raw materials, water washed conttonseed meal can be used in wood bonding. To produce “...

  19. CO2-based hydrogen storage - Hydrogen generation from formaldehyde/water

    Science.gov (United States)

    Trincado, Monica; Grützmacher, Hansjörg; Prechtl, Martin H. G.

    2018-04-01

    Formaldehyde (CH2O) is the simplest and most significant industrially produced aldehyde. The global demand is about 30 megatons annually. Industrially it is produced by oxidation of methanol under energy intensive conditions. More recently, new fields of application for the use of formaldehyde and its derivatives as, i.e. cross-linker for resins or disinfectant, have been suggested. Dialkoxymethane has been envisioned as a combustion fuel for conventional engines or aqueous formaldehyde and paraformaldehyde may act as a liquid organic hydrogen carrier molecule (LOHC) for hydrogen generation to be used for hydrogen fuel cells. For the realization of these processes, it requires less energy-intensive technologies for the synthesis of formaldehyde. This overview summarizes the recent developments in low-temperature reductive synthesis of formaldehyde and its derivatives and low-temperature formaldehyde reforming. These aspects are important for the future demands on modern societies' energy management, in the form of a methanol and hydrogen economy, and the required formaldehyde feedstock for the manufacture of many formaldehyde-based daily products.

  20. Solid phase microextraction method development for measuring Henry's Law constants of formaldehyde in aqueous solutions

    Science.gov (United States)

    Formaldehyde (HCHO) has been of special concern as an indoor air pollutant because of its existence in a wide range of products and its adverse health effects. The air-water partitioning behavior of volatile organic compounds (VOCs) such as formaldehyde is an important process th...

  1. Cells deficient in the FANC/BRCA pathway are hypersensitive to plasma levels of formaldehyde.

    Science.gov (United States)

    Ridpath, John R; Nakamura, Ayumi; Tano, Keizo; Luke, April M; Sonoda, Eiichiro; Arakawa, Hiroshi; Buerstedde, Jean-Marie; Gillespie, David A F; Sale, Julian E; Yamazoe, Mitsuyoshi; Bishop, Douglas K; Takata, Minoru; Takeda, Shunichi; Watanabe, Masami; Swenberg, James A; Nakamura, Jun

    2007-12-01

    Formaldehyde is an aliphatic monoaldehyde and is a highly reactive environmental human carcinogen. Whereas humans are continuously exposed to exogenous formaldehyde, this reactive aldehyde is a naturally occurring biological compound that is present in human plasma at concentrations ranging from 13 to 97 micromol/L. It has been well documented that DNA-protein crosslinks (DPC) likely play an important role with regard to the genotoxicity and carcinogenicity of formaldehyde. However, little is known about which DNA damage response pathways are essential for cells to counteract formaldehyde. In the present study, we first assessed the DNA damage response to plasma levels of formaldehyde using chicken DT40 cells with targeted mutations in various DNA repair genes. Here, we show that the hypersensitivity to formaldehyde is detected in DT40 mutants deficient in the BRCA/FANC pathway, homologous recombination, or translesion DNA synthesis. In addition, FANCD2-deficient DT40 cells are hypersensitive to acetaldehyde, but not to acrolein, crotonaldehyde, glyoxal, and methylglyoxal. Human cells deficient in FANCC and FANCG are also hypersensitive to plasma levels of formaldehyde. These results indicate that the BRCA/FANC pathway is essential to counteract DPCs caused by aliphatic monoaldehydes. Based on the results obtained in the present study, we are currently proposing that endogenous formaldehyde might have an effect on highly proliferating cells, such as bone marrow cells, as well as an etiology of cancer in Fanconi anemia patients.

  2. Portable formaldehyde monitoring device using porous glass sensor and its applications in indoor air quality studies.

    Science.gov (United States)

    Maruo, Yasuko Yamada; Nakamura, Jiro

    2011-09-30

    We have developed a portable device for formaldehyde monitoring with both high sensitivity and high temporal resolution, and carried out indoor air formaldehyde concentration analysis. The absorbance difference of the sensor element was measured in the monitoring device at regular intervals of, for example, one hour or 30 min, and the result was converted into the formaldehyde concentration. This was possible because we found that the lutidine derivative that was formed as a yellow product of the reaction between 1-phenyl-1,3-butandione and formaldehyde was stable in porous glass for at least six months. We estimated the reaction rate and to be 0.049 min(-1) and the reaction occurred quickly enough for us to monitor hourly changes in the formaldehyde concentration. The detection limit was 5 μg m(-3) h. We achieved hourly formaldehyde monitoring using the developed device under several indoor conditions, and estimated the air exchange rate and formaldehyde adsorption rate, which we adopted as a new term in the mass balance equation for formaldehyde, in one office. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Simultaneous bond degradation and bond formation during phenol-formaldehyde curing with wood

    Science.gov (United States)

    Daniel J. Yelle; John Ralph

    2016-01-01

    Bonding of wood using phenol–formaldehyde adhesive develops highly durable bonds. Phenol– formaldehyde is believed to form primary bonds with wood cell wall polymers (e.g., lignin). However, it is unclear how this adhesive interacts and bonds to lignin. Through wood solubilisation methodologies, earlywood and latewood bonded assemblies were characterized using two-...

  4. 24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban Development Regulations Relating to... Body and Frame Construction Requirements § 3280.308 Formaldehyde emission controls for certain wood...

  5. 75 FR 37792 - Formaldehyde Gas; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Science.gov (United States)

    2010-06-30

    ... Emergency Management, Office of Solid Waste and Emergency Response (OSWER) to use formaldehyde gas (CAS No... American Industrial Classification System (NAICS) codes have been provided to assist you and others in... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2010-0420; FRL-8828-9] Formaldehyde Gas; Receipt of...

  6. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    Science.gov (United States)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  7. A new system to reduce formaldehyde levels improves safety conditions during gross veterinary anatomy learning.

    Science.gov (United States)

    Nacher, Víctor; Llombart, Cristina; Carretero, Ana; Navarro, Marc; Ysern, Pere; Calero, Sebastián; Fígols, Enric; Ruberte, Jesús

    2007-01-01

    Dissection is a very useful method of learning veterinary anatomy. However, formaldehyde, which is widely used to preserve cadavers, is an irritant, and it has recently been classified as a carcinogen. In 1997, the Instituto Nacional de Seguridad e Higiene en el Trabajo [National Institute of Workplace Security and Hygiene] found that the levels of formaldehyde in our dissection room were above the threshold limit values. Unfortunately, no optimal substitute for formaldehyde is currently available. Therefore, we designed a new ventilation system that combines slow propulsion of fresh air from above the dissection table and rapid aspiration of polluted air from the perimeter. Formaldehyde measurements performed in 2004, after the introduction of this new system into our dissection laboratory, showed a dramatic reduction (about tenfold, or 0.03 ppm). A suitable propelling/aspirating air system successfully reduces the concentration of formaldehyde in the dissection room, significantly improving safety conditions for students, instructors, and technical staff during gross anatomy learning.

  8. A survey of formaldehyde in the Cepheus OB3 molecular cloud

    International Nuclear Information System (INIS)

    Few, R.W.; Cohen, R.J.

    1983-01-01

    The 1 11 - 1 10 absorption line of formaldehyde at 6-cm wavelength has been surveyed over the region of the Cepheus OB3 molecular cloud, using the Jodrell Bank Mk II radio telescope (beamwidth 9 x 10 arcmin 2 ). The measurements have a velocity resolution of 0.27 km s - 1 and an rms noise level of approx. 0.01 K. The formaldehyde has a very clumpy distribution which is broadly similar to the CO distribution found by Sargent. A total molecular mass of 1.9 x 10 4 solar masses is implied by the formaldehyde measurements. Cepheus A is not the dominant concentration in the formaldehyde map. The most massive formaldehyde concentration is Cepheus C, which has a mass of 3600 solar masses. It appears to be stabilized by rotation. (author)

  9. Effect of electric field on adsorption of formaldehyde by β-cellobiose in micro-scale

    Science.gov (United States)

    Xu, Bo; Chen, Zhenqian

    2018-05-01

    To provide a microcosmic theoretical support for the reduction of formaldehyde in building material by the effect of electric fields, the adsorption between formaldehyde molecule and β-cellobiose was studied by density function theory (DFT). Details of geometric structures, molecule bonds and adsorption energy were discussed respectively. The obtained results indicated the energy of formaldehyde molecule decreased while the energy of β-cellobiose increased with greater electric intensity. In addition, the adsorption energy between formaldehyde molecule and β-cellobiose was greatly influenced by external electric field. The adsorption energy reduced gradually with greater electric intensity, and the changing curve of adsorption energy could be fitted as an exponential function, verified by the experiment. The results of this study confirmed the external electric field would be a good strategy for decreasing formaldehyde within building materials in the microcosmic view.

  10. Combined effect of formaldehyde and gamma-irradiation. Vitamin complex effect

    International Nuclear Information System (INIS)

    Ban'kovskij, A.A.; El'chaninova, M.A.

    1996-01-01

    Combined inhalation effect of formaldehyde and gamma-irradiation on the activities of alcohol and aldehyde dehydrogenases in rat lung tissue was studied. The possibility of fitting the parameters studied by the vitamin PP, A and E and complex was shown. At investigation of white rats in conditions of formaldehyde inhalation in concentration 10 mg/m 3 and gamma-irradiation by dose 0.25 Gy the changes of activities of alcohol and aldehyde dehydrogenases in the rat lung tissue were detected. An injection of PP, A and E vitamin complex after combined effect of formaldehyde and gamma-irradiation contributes to normalization of studied parameters. The K(C -1 ) constant is reduced. On this basis it is proposed that in such conditions formaldehyde stabilizes membranes and protects important metabolic processes against damages. Thus, vitamin complex is capable to level a toxic combined effect of formaldehyde and gamma-irradiation. 9 refs., 1 tab

  11. Ayty: a New Line-List for Hot Formaldehyde

    Science.gov (United States)

    Al-Refaie, Ahmed Faris; Yurchenko, Sergei N.; Tennyson, Jonathan; Yachmenev, Andrey

    2015-06-01

    The ExoMol [1] project aims at providing spectroscopic data for key molecules that can be used to characterize the atmospheres of exoplanets and cool stars. Formaldehyde (H2CO) is of growing importance in studying and modelling terrestrial atmospheric chemistry and dynamics. It also has relevance in astrophysical phenomena that include interstellar medium abundance, proto-planetary and cometary ice chemistry and masers from extra-galactic sources. However there gaps in currently available absolute intensities and a lack of higher rotational excitations that makes it unfeasible to accurately model high temperature systems such as hot Jupiters. Here we present AYTY [2], a new line list for formaldehyde applicable to temperatures up to 1500 K. AYTY contains almost 10 million states reaching rotational excitations up to J=70 and over 10 billion transitions at up to 10 000 cm-1. The line list was computed using the variational ro-vibrational solver TROVE with a refined ab-initio potential energy surface and dipole moment surface. J.~Tennyson and S.~N. Yurchenko MNRAS, 425:21--33, 2012. A.~F. Al-Refaie, S.~N. Yurchenko, A.~Yachmenev, and J.~Tennyson MNRAS, 2015.

  12. Effects of Sodium Selenite on Formaldehyde Induced Renal Toxicity in Mice

    Directory of Open Access Journals (Sweden)

    Shabnam Mohammadi 1,2 * , Maryam Moghimian 3, Hanieh Torabzadeh 4, Mahla Langari 4, Roghayeh Nazeri 4, Zahra Karimi 4, Elham Sangari 4, Najmeh Jagarmi 5, Alireza Mohammad Zadeh 3, Mehdi Karimi 7, Kamyar Tavakkoli 8, Ali Delshad 9, Fatemeh Mohammadzadeh 3, Majid Ghayour-Mobarhan 10

    2016-12-01

    Full Text Available Background: Formaldehyde is widely used for industrial applications. Renal injury is an adverse effect associated with formaldehyde. Few studies have explored the potential benefits of protective factors on formaldehyde induced renal toxicity. This study evaluated the dose dependent effects of sodium selenite on the biochemical and histopathological effects of formaldehyde on murine kidney. Methods: Forty eight adult Balb/c male mice were randomized into six groups: a control group, a formaldehyde group and experimental III-VI groups. Formaldehyde group was injected with 10 mg/kg formaldehyde and groups III-VI received intraperitoneally doses of 0.1, 0.2, 0.4, 0.8 mg/kg selenium. After two weeks, a stereological study was done in accordance with the principle of Cavalieri and serum concentrations of urea and creatinine were measured. Data were analyzed using ANOVA and SPSS software. Results: Glomerosclerosis, necrosis and vacuolization were observed in the convoluted tubules of animals treated with formaldehyde. The biochemical markers, volume and count of glomeruli in the group treated with formaldehyde was significantly difference compared to the control group (P<0.05. The volume of the glomeruli in the group treated with 0.2 and 0.4 mg selenium and urea level in the group treated with 0.4 and 0.1 mg/kg selenium was significantly difference compared to the control group (P <0.05. The count of glomeruli and creatinine level in the selenium group was significantly difference compared to the control group (P ≤ 0.0001. Conclusions: A dose of 0.2 mg/kg of sodium selenite caused partial protective effect on the renal tissue and function in exposed to formaldehyde.

  13. Multicenter Patch Testing With a Resol Resin Based on Phenol and Formaldehyde Within the International Contact Dermatitis Research Group

    DEFF Research Database (Denmark)

    Isaksson, M.; Ale, I.; Andersen, Klaus Ejner

    2015-01-01

    Background Contact allergy to phenol-formaldehyde resins (PFRs) based on phenol and formaldehyde is not detected by a p-tertiary-butylphenol-formaldehyde resin included in most baseline patch test series. Objective The aims of this study were to investigate the contact allergy rate to PFR-2.......2%) reacted to PFR-2. Of those 28 individuals, one had a positive reaction to formaldehyde and 2 to p-tertiary-butylphenol-formaldehyde resin. Simultaneous allergic reactions were noted to colophonium in 3, to Myroxylon pereirae in 5, and to fragrance mix I in 8. Conclusions The contact allergy frequency...

  14. Observations of Carbon Isotopic Fractionation in Interstellar Formaldehyde

    Science.gov (United States)

    Wirstrom, E. S.; Charnley, S. B.; Geppert, W. D.; Persson, C. M.

    2012-01-01

    Primitive Solar System materials (e.g. chondrites. IDPs, the Stardust sample) show large variations in isotopic composition of the major volatiles (H, C, N, and O ) even within samples, witnessing to various degrees of processing in the protosolar nebula. For ex ample. the very pronounced D enhancements observed in IDPs [I] . are only generated in the cold. dense component of the interstellar medium (ISM), or protoplanetary disks, through ion-molecule reactions in the presence of interstellar dust. If this isotopic anomaly has an interstellar origin, this leaves open the possibility for preservation of other isotopic signatures throughout the form ation of the Solar System. The most common form of carbon in the ISM is CO molecules, and there are two potential sources of C-13 fractionation in this reservoir: low temperature chemistry and selective photodissociation. While gas-phase chemistry in cold interstellar clouds preferentially incorporates C-13 into CO [2], the effect of self-shielding in the presence of UV radiation instead leads to a relative enhancement of the more abundant isotopologue, 12CO. Solar System organic material exhibit rather small fluctuations in delta C-13 as compared to delta N-15 and delta D [3][1], the reason for which is still unclear. However, the fact that both C-13 depleted and enhanced material exists could indicate an interstellar origin where the two fractionation processes have both played a part. Formaldehyde (H2CO) is observed in the gas-phase in a wide range of interstellar environments, as well as in cometary comae. It is proposed as an important reactant in the formation of more complex organic molecules in the heated environments around young stars, and formaldehyde polymers have been suggested as the common origin of chondritic insoluable organic matter (IOM) and cometary refractory organic solids [4]. The relatively high gas-phase abundance of H2CO observed in molecular clouds (10(exp- 9) - 10(exp- 8) relative to H2) makes

  15. Determination of carbonyl compounds (acetaldehyde and formaldehyde in polyethylene terephthalate containers designated for water conservation

    Directory of Open Access Journals (Sweden)

    Redžepović Azra S.

    2012-01-01

    Full Text Available Polyethylene terephthalate (PET has in the last several years become the main packaging material for many food products, particularly carbonated beverages and bottled water, as well as for products of chemical industry (packaging of various hygiene maintenance agents, pesticides, solvents, etc.. The strength and permeability properties of PET are very good for packaging of beverages, its resistance to chemicals is high and it has a high degree of transparency. Acetaldehyde and formaldehyde are formed during the thermoforming of PET containers. After cooling, acetaldehyde and formaldehyde remain trapped in the walls of a PET bottle and may migrate into the water after filling and storage. Since there are no migration tests in Serbia prescribed for the determination of acetaldehyde and formaldehyde, the purpose of the paper is to test the quantitative contents of carbonyl compounds (acetaldehyde and formaldehyde in PET containers of different volumes, made by various manufacturers of bottled mineral carbonated and noncarbonated water, and exposed to different temperatures. In this study, the migration of acetaldehyde and formaldehyde from PET bottles into mineral carbonated and noncarbonated water was determined by high performance liquid chromatography. Taking into consideration that formaldehyde and acetaldehyde have no UV active or fluorescent group, the chromatography shall be preceded by derivatization in a closed system (due to a low boiling point of acetaldehyde and formaldehyde, which shall transform carbonyl compounds into UV active compounds.

  16. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage

    Science.gov (United States)

    Yu, Rui; Lai, Yongquan; Hartwell, Hadley J.; Moeller, Benjamin C.; Doyle-Eisele, Melanie; Kracko, Dean; Bodnar, Wanda M.; Starr, Thomas B.; Swenberg, James A.

    2015-01-01

    Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N2-hydroxymethyl-dG (N2-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N2-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [13CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N2-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency’s Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair. PMID:25904104

  17. Quantification of free formaldehyde in carrageenan and processed Eucheuma seaweed using high-performance liquid chromatography.

    Science.gov (United States)

    Hornshøj, Bettina Høj; Kobbelgaard, Sara; Blakemore, William R; Stapelfeldt, Henrik; Bixler, Harris J; Klinger, Markus

    2015-01-01

    In 2010 the European Commission placed a limit on the amount of free formaldehyde in carrageenan and processed Eucheuma seaweed (PES) of 5 mg kg(-1). Formaldehyde is not used in carrageenan and PES processing and accordingly one would not expect free formaldehyde to be present in carrageenan and PES. However, surprisingly high levels up to 10 mg kg(-1) have been found using the generally accepted AOAC and Hach tests. These findings are, per proposed reaction pathways, likely due to the formation of formaldehyde when sulphated galactose, the backbone of carrageenan, is hydrolysed with the strong acid used in these conventional tests. In order to minimise the risk of false-positives, which may lead to regulatory non-compliance, a new high-performance liquid chromatography (HPLC) method has been developed. Initially, carrageenan or PES is extracted with 2-propanol and subsequently reacted with 2,4-dinitrophenylhydrazine (DNPH) to form the chromophore formaldehyde-DNPH, which is finally quantified by reversed-phase HPLC with ultraviolet light detection at 355 nm. This method has been found to have a limit of detection of 0.05 mg kg(-1) and a limit of quantification of 0.2 mg kg(-1). Recoveries from samples spiked with known quantities of formaldehyde were 95-107%. Using this more specific technique, 20 samples of carrageenan and PES were tested for formaldehyde. Only one sample had a detectable content of formaldehyde (0.40 mg kg(-1)), thus demonstrating that the formaldehyde content of commercial carrageenan and PES products are well below the European Commission maximum limit of 5 mg kg(-1).

  18. Effect of catalyst on melamine-formaldehyde organic aerogel

    International Nuclear Information System (INIS)

    Sun Zhipeng; Yang Xi; Fu Zhibing; Zhong Minglong; Wang Chaoyang; Ma Kangfu; Huang Xiaoli; Chang Lijuan

    2013-01-01

    A series of melamine-formaldehyde(MF) organic aerogel templates were prepared with different categories and concentration of catalyst. Their molecular structure, thermal stability and pore structure were tested by Fourier transform infrared spectroscopy, thermogravimetric analysis and nitrogen adsorption. It is indicated that the type and concentration of catalyst do not affect molecular structure and thermal stability of the MF organic aerogel template. The specific surface area and pore volume of the MF organic aerogel template using Na 2 CO 3 as catalyst are higher than those using NaOH, NaHCO 3 as catalyst. When the ratio of the concentration of melamine to that of catalyst is 500, the specific surface area is maximized. (authors)

  19. Radiation-chemical hardening of phenol-formaldehyde oligomers

    International Nuclear Information System (INIS)

    Shlapatskaya, V.V.; Omel'chenko, S.I.

    1978-01-01

    Radiation-chemical hardening of phenol formaldehyde oligomers of the resol type has been studied in the presence of furfural and diallylphthalate diluents. The samples have been hardened on an electron accelerator at an electron energy of 1.0-1.1 MeV and a dose rate of 2-3 Mrad/s. The kinetics of hardening has been studied on the yield of gel fraction within the range of absorbed doses from 7 to 400 Mrad. Radiation-chemical hardening of the studied compositions is activated with sensitizers, namely, amines, metal chlorides, and heterocyclic derivatives of metals. Furfural and diallylphthalate compositions are suitable for forming glass-fibre plastic items by the wet method and coatings under the action of ionizing radiations

  20. Reactivity of Resorcinol Formaldehyde Resin with Nitric Acid

    International Nuclear Information System (INIS)

    King, William D.; Fondeur, Fernando F.; Wilmarth, William R.; Pettis, Myra E.

    2005-01-01

    Solid-state infrared spectroscopy, differential scanning calorimetry, and elemental analysis have been used to evaluate the reactivity of resorcinol formaldehyde resin with nitric acid and characterize the solid product. Two distinct reactions were identified within the temperature range 25-55 C. The first reaction is primarily associated with resin nitration, while the second involves bulk oxidation and degradation of the polymer network leading to dissolution and off-gassing. The threshold conditions promoting reaction have been identified. Reaction was confirmed with nitric acid concentrations as low as 3 M at 25 C applied temperature and 0.625 M at 66 C. Although a nitrated resin product can be isolated under appropriate experimental conditions, calorimetry testing indicates no significant hazard associated with handling the dry material

  1. Some characteristics of urea-formaldehyde powder adhesives

    Directory of Open Access Journals (Sweden)

    Miljković Jovan

    2006-01-01

    Full Text Available Urea-formaldehyde (UF glue resins were the most important type of adhesives in the wood industry last 60 years, especially for the production of wood based panels. More convenient spray dried UF powders went into use last two decades. Small and medium private wood processing plants in Serbia prefer to use such powder adhesives, since they are more convenient for small capacity production. There is no production of UF powder resin in Serbia so necessary quantities are imported from abroad including producers from Asia. However, their characteristics are variable, dependent on syntheses steps and not well known among users. Objective of this research was to determine conveniences and lacks in application of two imported UF powder resins in comparison to domestic UF emulsion.

  2. Calculations on the vibrational level density in highly excited formaldehyde

    International Nuclear Information System (INIS)

    Rashev, Svetoslav; Moule, David C.

    2003-01-01

    The object of the present work is to develop a model that provides realistic estimates of the vibrational level density in polyatomic molecules in a given electronic state, at very high (chemically relevant) vibrational excitation energies. For S 0 formaldehyde (D 2 CO), acetylene, and a number of triatomics, the estimates using conventional spectroscopic formulas have yielded densities at the dissociation threshold, very much lower than the experimentally measured values. In the present work we have derived a general formula for the vibrational energy levels of a polyatomic molecule, which is a generalization of the conventional Dunham spectroscopic expansion. Calculations were performed on the vibrational level density in S 0 D 2 CO, H 2 C 2 , and NO 2 at excitation energies in the vicinity of the dissociation limit, using the newly derived formula. The results from the calculations are in reasonable agreement with the experimentally measured data

  3. Studies of Deactivation of Methanol to Formaldehyde Selective Oxidation Catalyst

    DEFF Research Database (Denmark)

    Raun, Kristian Viegaard; Schumann, Max; Høj, Martin

    Formaldehyde (CH2O) may be synthesized industrially by selective oxidation of methanol over an iron-molybdate (Fe-Mo) oxide catalyst according to: CH3OH + ½O2 →CH2O + H2O. The reaction is normally carried out in a multitubular reactor with excess of air at 250-400 °C (yield = 90-95 %), known...... the activity of the catalyst [2]. Pure MoO3 in itself has low activity. Literature from the last decades agrees that the major reason for the deactivation is loss of molybdenum from the catalyst. Molybdenum forms volatile species with methanol, which can leave behind Mo poor zones. The catalyst is usually...

  4. PRODUCTION OF HIGH DENSITY PARTICLEBOARD USING MELAMINE-UREA-FORMALDEHYDE RESIN

    Directory of Open Access Journals (Sweden)

    Setsuo Iwakiri

    2005-12-01

    Full Text Available This research was developed aiming to evaluate the effects of board density and melamine-urea-formaldehyde resin onthe properties of particleboard for semi-structural applications. The boards were manufactured with nominal density of 0.65 g/cm³and 0.90 g/cm³ using urea-formaldehyde resin as control and melamine-urea-formaldehyde. The results showed a better dimensionallystability and mechanical properties of the boards manufactured with higher density and MUF resin content. The fine furnish usedfor external layer of particleboard in the industrial process, could be used for high density homogeneous board to semi-strucuturaluses, such as flooring applications.

  5. Guinea pig maximization tests with formaldehyde releasers. Results from two laboratories

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Boman, A; Hamann, K

    1984-01-01

    The guinea pig maximization test was used to evaluate the sensitizing potential of formaldehyde and 6 formaldehyde releasers (Forcide 78, Germall 115, Grotan BK, Grotan OX, KM 200 and Preventol D2). The tests were carried out in 2 laboratories (Copenhagen and Stockholm), and although we intended...... the procedures to be the same, discrepancies were observed, possibly due to the use of different animal strains, test concentrations and vehicles. The sensitizing potential was in general found to be stronger in Stockholm compared to Copenhagen: formaldehyde sensitized 50% of the guinea pigs in Copenhagen and 95...

  6. Destruction of nitric acid in purex process streams by formaldehyde treatment

    International Nuclear Information System (INIS)

    Kumar, S.V.; Nadkarni, M.N.; Mayankutty, P.C.; Pillai, N.S.; Shinde, S.S.

    1974-01-01

    Efficiency of destruction of nitric acid in purex process streams with formaldehyde has been studied as a function of initial acidity, uranium concentration, rate of addition of formaldehyde and temperature in the range 6 - 0.5M acid. Guidelines are suggested for the accurate calculations of the volume of formaldehyde needed to effect the required change of acidity at 100degC. Sodium nitrite has been established as a 'key' to initiate the reaction and water as an effective scrubber for collecting the acid fumes emanating from the reaction vessel. (author)

  7. Preparation of Diatomite Supported Nano Zinc Oxide Composite Photocatalytic Material and Study on its Formaldehyde Degradation

    Science.gov (United States)

    Xiao, Liguang; Pang, Bo

    2017-09-01

    This experiment used zinc nitrate as precursor, ethanol as solvent and polyethylene glycol as dispersant, diatomite as carrier, diatomite loaded nano Zinc Oxide was prepared by sol-gel method, in addition, the formaldehyde degradation was studied by two kinds of experimental methods: preparation and loading, preparation and post loading, The samples were characterized by SEM, XRD, BET and IR. Experimental results showed that: Diatomite based nano Zinc Oxide had a continuous adsorption and degradation of formaldehyde, formaldehyde gas with initial concentration was 0.7mg/m3, after 36h degradation, the concentration reached 0.238mg/m3, the degradation rate reached to 66%.

  8. SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

    Directory of Open Access Journals (Sweden)

    G. Dufour

    2009-03-01

    Full Text Available Formaldehyde (HCHO is an important intermediate compound in the degradation of volatile organic compounds (VOCs in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1 the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×1015 molecule/cm2 and the model performances evaluated using surface measurements are satisfactory (~13%; (2 the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa to a factor of 2 (Poland, the United Kingdom depending on the regions.

  9. Microwave Assisted Solvent Free Synthesis of Azomethines from Aryl Aldehydes on Melamin Formaldehyde as Solid Support

    Directory of Open Access Journals (Sweden)

    Ramin Rezaei

    2011-01-01

    Full Text Available Various aryl aldehydes underwent prompt one pot conversion into the corresponding azomethines in high yields by reacting with hydroxylamine hydrochloride supported on melamine formaldehyde under microwave irradiation.

  10. FORMALDEHYDE-INDUCED GENE EXPRESSION IN F344 RAT NASAL RESPIRATORY EPITHELIUM.

    Science.gov (United States)

    Formaldehyde-induced gene expression in F344 rat nasal respiratory epithelium ABSTRACTFormaldehyde, an occupational and environmental toxicant used extensively in the manufacturing of many household and personal use products, is known to induce squamous cell carci...

  11. Photochemical decomposition of Formaldehyde in solution.; Descomposicion fotoquimica de formaldehido en solucion.

    Energy Technology Data Exchange (ETDEWEB)

    Garrido Z, G

    1995-10-01

    In this work was studied the effect of ultraviolet radiation produced by a mercury low pressure lamp in solutions of formaldehyde. These solutions were exposed to ultraviolet rays at different times. In some of these series of solutions was added a photosensibilizer in order to obtain a high photodecomposition of formaldehyde. The techniques used for determine the products of the decomposition were the following: 1. In order to measure the residual formaldehyde and glioxal, the Hantzsch and 2,4-dinitrophenylhydrazine methods were used. 2. pH`s measurements of the solutions, before and after exposition. 3. Paper`s chromatography for determine presence of formed acids. 4. Acid-base tritiations for measure total acidification. We observed that when the time of exposition to UV rays was increased, a high photodecomposition of formaldehyde was formed and, besides, a greater quantity of another products. Of the reagents used like photosensibilizers, with the ruthenium reagent, the best results were obtained. (Author).

  12. Investigation of the detoxification mechanism of formaldehyde-treated tetanus toxin

    DEFF Research Database (Denmark)

    Thaysen-Andersen, Morten; Jørgensen, Sys Borcher; Wilhelmsen, Ellen Sloth

    2007-01-01

    and properties of the vaccine component, occurs through partly unknown chemical modifications of the toxin. The aim of this study was to gain knowledge of the detoxification mechanism in the generation of the tetanus vaccine. Two approaches were chosen: (i) the effect of changes in the concentrations of lysine...... The tetanus vaccine is based on the extremely potent tetanus neurotoxin (TeNT), which is converted by treatment with formaldehyde and lysine into the non-toxic, but still immunogenic tetanus toxoid (TTd). This formaldehyde-induced detoxification, which to a large extend determines the quality...... and formaldehyde in the detoxification process and (ii) characterisation of the chemically detoxified TTd. (i) We examined a number of TTd components that was produced by varying the concentrations of formaldehyde and lysine during the inactivation. Toxicity tests showed that the detoxification failed when...

  13. Formaldehyd i tekstil som mulig årsag til arthritis og angioødem

    DEFF Research Database (Denmark)

    Jensen, O C; Bach, B

    1992-01-01

    A case of arthritis and angioedema which developed on occupational exposure to formaldehyde in textiles is described. Possible pathological mechanisms are discussed. The suspicion that an unknown immunological reaction may be the cause is raised....

  14. Biofiltration of waste gases containing a mixture of formaldehyde and methanol.

    Science.gov (United States)

    Prado, Oscar J; Veiga, María C; Kennes, Christian

    2004-08-01

    Several biofilters and biotrickling filters were used for the treatment of a mixture of formaldehyde and methanol; and their efficiencies were compared. Results obtained with three different inert filter bed materials (lava rock, perlite, activated carbon) suggested that the packing material had only little influence on the performance. The best results were obtained in a biotrickling filter packed with lava rock and fed a nutrient solution that was renewed weekly. A maximum formaldehyde elimination capacity of 180 g m(-3) h(-1) was reached, while the methanol elimination capacity rose occasionally to more than 600 g m(-3) h(-1). Formaldehyde degradation was affected by the inlet methanol concentration. Several combinations of load vs empty bed residence time (EBRTs of 71.9, 46.5, 30.0, 20.7 s) were studied, reaching a formaldehyde elimination capacity of 112 g m(-3) h(-1) with about 80% removal efficiency at the lowest EBRT (20.7 s).

  15. CeO2 thin film as a low-temperature formaldehyde sensor in mixed ...

    Indian Academy of Sciences (India)

    Administrator

    vapour sensing properties of the cerium oxide film in mixed environment were studied and reported. Keywords. .... The output signal from the op-amp is connected to a computer- controlled .... film as a function of formaldehyde concentration.

  16. Improved Nissl method to stain formaldehyde or glutaraldehyde-fixed material.

    Science.gov (United States)

    Böck, P

    1979-05-15

    Nissl staining of paraffin sections from formaldehyde- or glutaraldehyde-fixed specimens is significantly intensified when sections are kept in a 50% (w/v) aqueous solution of potassium metabisulfite before being stained by a conventional Nissl method.

  17. Cohort mortality study of garment industry workers exposed to formaldehyde: update and internal comparisons.

    Science.gov (United States)

    Meyers, Alysha R; Pinkerton, Lynne E; Hein, Misty J

    2013-09-01

    To further evaluate the association between formaldehyde and leukemia, we extended follow-up through 2008 for a cohort mortality study of 11,043 US formaldehyde-exposed garment workers. We computed standardized mortality ratios and standardized rate ratios stratified by year of first exposure, exposure duration, and time since first exposure. Associations between exposure duration and rates of leukemia and myeloid leukemia were further examined using Poisson regression models. Compared to the US population, myeloid leukemia mortality was elevated but overall leukemia mortality was not. In internal analyses, overall leukemia mortality increased with increasing exposure duration and this trend was statistically significant. We continue to see limited evidence of an association between formaldehyde and leukemia. However, the extended follow-up did not strengthen previously observed associations. In addition to continued epidemiologic research, we recommend further research to evaluate the biological plausibility of a causal relation between formaldehyde and leukemia. Copyright © 2013 Wiley Periodicals, Inc.

  18. The Effectors and Sensory Sites of Formaldehyde-responsive Regulator FrmR and Metal-sensing Variant *

    Science.gov (United States)

    Osman, Deenah; Piergentili, Cecilia; Chen, Junjun; Sayer, Lucy N.; Usón, Isabel; Huggins, Thomas G.; Robinson, Nigel J.; Pohl, Ehmke

    2016-01-01

    The DUF156 family of DNA-binding transcriptional regulators includes metal sensors that respond to cobalt and/or nickel (RcnR, InrS) or copper (CsoR) plus CstR, which responds to persulfide, and formaldehyde-responsive FrmR. Unexpectedly, the allosteric mechanism of FrmR from Salmonella enterica serovar Typhimurium is triggered by metals in vitro, and variant FrmRE64H gains responsiveness to Zn(II) and cobalt in vivo. Here we establish that the allosteric mechanism of FrmR is triggered directly by formaldehyde in vitro. Sensitivity to formaldehyde requires a cysteine (Cys35 in FrmR) conserved in all DUF156 proteins. A crystal structure of metal- and formaldehyde-sensing FrmRE64H reveals that an FrmR-specific amino-terminal Pro2 is proximal to Cys35, and these residues form the deduced formaldehyde-sensing site. Evidence is presented that implies that residues spatially close to the conserved cysteine tune the sensitivities of DUF156 proteins above or below critical thresholds for different effectors, generating the semblance of specificity within cells. Relative to FrmR, RcnR is less responsive to formaldehyde in vitro, and RcnR does not sense formaldehyde in vivo, but reciprocal mutations FrmRP2S and RcnRS2P, respectively, impair and enhance formaldehyde reactivity in vitro. Formaldehyde detoxification by FrmA requires S-(hydroxymethyl)glutathione, yet glutathione inhibits formaldehyde detection by FrmR in vivo and in vitro. Quantifying the number of FrmR molecules per cell and modeling formaldehyde modification as a function of [formaldehyde] demonstrates that FrmR reactivity is optimized such that FrmR is modified and frmRA is derepressed at lower [formaldehyde] than required to generate S-(hydroxymethyl)glutathione. Expression of FrmA is thereby coordinated with the accumulation of its substrate. PMID:27474740

  19. Cross-Aldol condensation of isobutyraldehyde and formaldehyde using phase transfer catalyst

    Directory of Open Access Journals (Sweden)

    Azhar Hashmi

    2016-09-01

    Full Text Available The hydroxypivaldehyde (HPA precursor intermediate for the synthesis of neopentyl glycol (NPG is prepared by novel cross Aldol condensation of isobutyraldehyde and formaldehyde at 20 °C using benzyltrimethylammonium hydroxide, a basic phase transfer catalyst. A feed mole ratio of 1.1:1.0:0.04 (isobutyraldehyde:formaldehyde:benzyltrimethylammonium hydroxide afforded hydroxypivaldehyde as white solid in almost quantitative yield with ∼100% selectivity.

  20. Cross-Aldol condensation of isobutyraldehyde and formaldehyde using phase transfer catalyst

    OpenAIRE

    Azhar Hashmi

    2016-01-01

    The hydroxypivaldehyde (HPA) precursor intermediate for the synthesis of neopentyl glycol (NPG) is prepared by novel cross Aldol condensation of isobutyraldehyde and formaldehyde at 20 °C using benzyltrimethylammonium hydroxide, a basic phase transfer catalyst. A feed mole ratio of 1.1:1.0:0.04 (isobutyraldehyde:formaldehyde:benzyltrimethylammonium hydroxide) afforded hydroxypivaldehyde as white solid in almost quantitative yield with ∼100% selectivity.

  1. Adsorption of Pb, Cd, Zn, Cu and Hg ions on Formaldehyde and ...

    African Journals Online (AJOL)

    Adsorption of Pb(II), Cd(II), Zn(II), Cu(II) and Hg(II) ions on formaldehyde and Pyridine modified bean husks were determined. The adsorption capacity of formaldehyde modified bean husks (mg/g) was: Pb2+, 5.01; Cd2+, 3.63; Zn2+, 2.18; Hg2+, 1.82; Cu2+, 1.58 and that of pyridine modified bean husk was: Hg2+, 6.92; Cd2+ ...

  2. Formaldehyde and TVOC emission behavior of laminate flooring by structure of laminate flooring and heating condition.

    Science.gov (United States)

    An, Jae-Yoon; Kim, Sumin; Kim, Hyun-Joong

    2011-03-15

    Formaldehyde was measured with a desiccator, a 20 L chamber and the FLEC method. The formaldehyde emission rate from laminate was the highest at 32 °C using the desiccator, which then decreased with time. The formaldehyde emission using the 20 L small chamber and FLEC showed a similar tendency. There was a strong correlation between the formaldehyde and total volatile organic compounds (TVOCs) with both types of floorings using the two different methods. The formaldehyde emission rate and TVOC results were higher when tested using the FLEC method than with the 20 L small chamber method. The emission rate was affected by the joint edge length in laminate flooring. Toluene, ethylbenzene and xylene were the main VOCs emitted from laminate flooring, and there were more unidentified VOCs emitted than identified VOCs. The samples heated with a floor heating system emitted more formaldehyde than those heated using an air circulation system due to the temperature difference between the bottom panel and flooring. The TVOC emission level of the samples was higher when an air circulation system was used than when a floor heating system was used due to the high ventilation rate. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Investigation of formaldehyde pollution of tap water and rain water using a novel visual colorimetry.

    Science.gov (United States)

    Murai, K; Okano, M; Kuramitz, H; Hata, N; Kawakami, T; Taguchi, S

    2008-01-01

    The pollution of tap water and rain water with formaldehyde in Toyama Pref., Japan was investigated by means of a simple, rapid and cost-effective visual colorimetry developed by us. The levels of formaldehyde in three tap waters from different sources of dams on mountainside and a well-water pumped in urban area in Toyama Pref. were lower than 0.01 mg L(-1) that was the detection limit of the colorimetry. On the other hand, rain waters were seriously polluted with formaldehyde. Rain waters were sampled from three different sites (urban area, top of hill and industrial area) in Toyama Pref. from autumn to winter in 2006. The levels of formaldehyde in the rain waters ranged from 0.07 to 0.30 mg L(-1). The analytical results by the visual colorimetry were in good agreement with those obtained by GC-MS method. It was confirmed that the colorimetry is excellent for practical use for the determination of formaldehyde. It must be concerned about the pollution of rainwater with formaldehyde, when rain water is applied for tap water and miscellaneous purpose. Copyright IWA Publishing 2008.

  4. Design of a formaldehyde photodissociation process for carbon and oxygen isotope separation

    International Nuclear Information System (INIS)

    Stern, R.C.; Scheibner, K.F.

    1993-01-01

    The current shortage of 18 O has revived interest in using one step UV photodissociation of formaldehyde to enrich 13 C, 17 O and 18 O. The frequency doubled output of the copper laser pumped dye laser system currently in operation at LLNL can be used to drive this dissociation. The authors use a simple kinetics model and their experience with Atomic Vapor Laser Isotope Separation (AVLIS) process design to examine the relative merits of different designs for a formaldehyde photodissociation process. Given values for the molecular photoabsorption cross section, partition function, spectroscopic selectivity, collisional exchange and quenching cross sections (all as parameters), they perform a partial optimization in the space of illuminated area, formaldehyde pressure in each stage, and formaldehyde residence time in each stage. They examine the effect of cascade design (heads and tails staging) on molecule and photon utilization for each of the three isotope separation missions, and look in one case at the system's response to different ratios of laser to formaldehyde costs. Finally, they examine the relative cost of enrichment as a function of isotope and product assay. Emphasis is as much on the process design methodology, which is general, as on the specific application to formaldehyde

  5. Performance of optical biosensor using alcohol oxidase enzyme for formaldehyde detection

    Science.gov (United States)

    Sari, A. P.; Rachim, A.; Nurlely, Fauzia, V.

    2017-07-01

    The recent issue in the world is the long exposure of formaldehyde which is can increase the risk of human health, therefore, that is very important to develop a device and method that can be optimized to detect the formaldehyde elements accurately, have a long lifetime and can be fabricated and produced in large quantities. A new and simple prepared optical biosensor for detection of formaldehyde in aqueous solutions using alcohol oxidase (AOX) enzyme was successfully fabricated. The poly-n-butyl acrylic-co-N-acryloxysuccinimide (nBA-NAS) membranes containing chromoionophore ETH5294 were used for immobilization of alcohol oxidase enzyme (AOX). Biosensor response was based on the colour change of chromoionophore as a result of enzymatic oxidation of formaldehyde and correlated with the detection concentration of formaldehyde. The performance of biosensor parameters were measured through the optical absorption value using UV-Vis spectrophotometer including the repeatability, reproducibility, selectivity and lifetime. The results showed that the prepared biosensor has good repeatability (RSD = 1.9 %) and good reproducibility (RSD = 2.1 %). The biosensor was selective formaldehyde with no disturbance by methanol, ethanol, and acetaldehyde, and also stable before 49 days and decrease by 41.77 % after 49 days.

  6. Nitrogen Doped Graphene Supported Pt Nanoflowers as Electrocatalysts for Oxidation of Formaldehyde.

    Science.gov (United States)

    Xie, Aijuan; Zhou, Wenting; Luo, Shiping; Chen, Yu; Zhou, Xiaoqing; Chao, Yao

    2017-02-01

    A facile Pt nanoflowers/nitrogen-doped graphene (PtNFs/NG) electrocatalyst was prepared via depositing Pt nanoflowers (PtNFs) onto the nitrogen-doped graphene (NG) matrix with urea as the nitrogen source and PtNFs/NG modified glassy carbon electrode (GCE) was prepared by electro-chemical method. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscope, X-ray photoelectron spectroscopy (XPS) and Scanning electron microscope (SEM) were used to characterize the resulting composites. Also oxidation of formaldehyde on the resulting PtNFs/NG modified electrode was investigated. The influence of deposition time, electrodeposition potential and formaldehyde concentration on electrooxidation of formaldehyde was detected, the experimental results indicate the high performance of PtNFs/NG catalyst for formaldehyde oxidation is at electrodeposition time of 300 s with the applied potential of −0.3 V. Electrochemical process, electrocatalytic stability and chronoamperometry were also inspected, it was indicated that formalde-hyde oxidation reaction on the PtNFs/NG electrode is diffusion-controlled and PtNFs/NG exhibits a high catalytic activity, stability as well as excellent poisoning-tolerance towards formaldehyde oxidation, which is attributed to the synergistic effect of PtNFs and NG. It turns out that PtNFs/NG can be used in direct liquid-feed fuel cells as a promising alternative catalyst.

  7. Graphene oxide as efficient high-concentration formaldehyde scavenger and reutilization in supercapacitor.

    Science.gov (United States)

    Liang, Hongyu; Bu, Yongfeng; Zhang, Yutian; Zhang, Junyan

    2015-04-15

    Graphene oxide (GO) was investigated as a low-cost and high-efficient scavenger for high-concentration formaldehyde in alkali media. It showed very high removal capacity, 411 mg of formaldehyde per milligram of GO, and strong resistant to temperature changes. Additionally, the used GO can be easily renewed by a simple electrochemical method. By analyzing the componential and electrochemical characterizations of GO before and after use, the results showed that the degradation mechanism of formaldehyde is a collaborative process of chemical oxidation and physical adsorption, and the former dominates the degradation process. With the aid of oxygen-containing groups in GO, most formaldehyde can be easily oxidized by GO in alkaline media (this is equivalent to GO was reduced by formaldehyde). On the other hand, the used GO (reduced GO, noted as rGO) exhibits more ideal electronic double-layer capacitor (EDLC) feature than GO, along with higher rate capacitance (up to 136 F g(-1) at 50 A g(-1)). In short, GO is not only an efficient formaldehyde scavenger, but the used GO (rGO) can serve as promising electrical energy storage material. This study provides new insights for us to reutilize the discarded adsorbents generated from the environmental protection. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Biochemical gas sensor (bio-sniffer) for ultrahigh-sensitive gaseous formaldehyde monitoring.

    Science.gov (United States)

    Kudo, Hiroyuki; Suzuki, Yuki; Gessei, Tomoko; Takahashi, Daishi; Arakawa, Takahiro; Mitsubayashi, Kohji

    2010-10-15

    An ultrahigh-sensitive fiber-optic biochemical gas sensor (bio-sniffer) for continuous monitoring of indoor formaldehyde was constructed and tested. The bio-sniffer measures gaseous formaldehyde as fluorescence of nicotinamide adenine dinucleotide (NADH), which is the product of formaldehyde dehydrogenase (FALDH) reaction. The bio-sniffer device was constructed by attaching a flow cell with a FALDH immobilized membrane onto a fiber-optic NADH measurement system. The NADH measurement system utilizes an ultraviolet-light emitting diode (UV-LED) with peak emission of 335 nm as an excitation light source. The excitation light was introduced to an optical fiber probe, and fluorescence emission of neighboring NADH, which was produced by applying formaldehyde vapor to the FALDH membrane, was concentrically measured with a photomultiplier tube. Assessment of the bio-sniffer was carried out using a standard gas generator. Response, calibration range and selectivity to other chemical substances were investigated. Circulating phosphate buffer, which contained NAD+, available for continuous monitoring of formaldehyde vapor. The calibration range of the bio-sniffer was 2.5 ppb to 10 ppm, which covers the guideline value of the World Health Organization (80 ppb). High selectivity to other gaseous substances due to specific activity of FALDH was also confirmed. Considering its high sensitivity, a possible application of the bio-sniffer is continuous indoor formaldehyde monitoring to provide healthy residential atmosphere. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. A Simple Approach to Distinguish Classic and Formaldehyde-Free Tannin Based Rigid Foams by ATR FT-IR

    Directory of Open Access Journals (Sweden)

    Gianluca Tondi

    2015-01-01

    Full Text Available Tannin based rigid foams (TBRFs have been produced with formaldehyde since 1994. Only recently several methods have been developed in order to produce these foams without using formaldehyde. TBRFs with and without formaldehyde are visually indistinguishable; therefore a method for determining the differences between these foams had to be found. The attenuated total reflectance infrared spectroscopy (ATR FT-IR investigation of the TBRFs presented in this paper allowed discrimination between the formaldehyde-containing (classic and formaldehyde-free TBRFs. The spectra of the formaldehyde-free TBRFs, indeed, present decreased band intensity related to the C–O stretching vibration of (i the methylol groups and (ii the furanic rings. This evidence served to prove the chemical difference between the two TBRFs and explained the slightly higher mechanical properties measured for the classic TBRFs.

  10. Bimodal activated carbons derived from resorcinol-formaldehyde cryogels

    Science.gov (United States)

    Szczurek, Andrzej; Amaral-Labat, Gisele; Fierro, Vanessa; Pizzi, Antonio; Celzard, Alain

    2011-01-01

    Resorcinol-formaldehyde cryogels prepared at different dilution ratios have been activated with phosphoric acid at 450 °C and compared with their carbonaceous counterparts obtained by pyrolysis at 900 °C. Whereas the latter were, as expected, highly mesoporous carbons, the former cryogels had very different pore textures. Highly diluted cryogels allowed preparation of microporous materials with high surface areas, but activation of initially dense cryogels led to almost non-porous carbons, with much lower surface areas than those obtained by pyrolysis. The optimal acid concentration for activation, corresponding to stoichiometry between molecules of acid and hydroxyl groups, was 2 M l−1, and the acid–cryogel contact time also had an optimal value. Such optimization allowed us to achieve surface areas and micropore volumes among the highest ever obtained by activation with H3PO4, close to 2200 m2 g−1 and 0.7 cm3 g−1, respectively. Activation of diluted cryogels with a lower acid concentration of 1.2 M l−1 led to authentic bimodal activated carbons, having a surface area as high as 1780 m2 g−1 and 0.6 cm3 g−1 of microporous volume easily accessible through a widely developed macroporosity. PMID:27877405

  11. Bimodal activated carbons derived from resorcinol-formaldehyde cryogels

    Energy Technology Data Exchange (ETDEWEB)

    Szczurek, Andrzej; Amaral-Labat, Gisele; Fierro, Vanessa; Celzard, Alain [Institut Jean Lamour-UMR CNRS 7198, CNRS-Nancy-Universite-UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces. ENSTIB, 27 rue Philippe Seguin, BP 1041, 88051 Epinal cedex 9 (France); Pizzi, Antonio, E-mail: Alain.Celzard@enstib.uhp-nancy.fr [ENSTIB-LERMAB, Nancy-Universite, 27 rue Philippe Seguin, BP1041, 88051 Epinal cedex 9 (France)

    2011-06-15

    Resorcinol-formaldehyde cryogels prepared at different dilution ratios have been activated with phosphoric acid at 450 deg. C and compared with their carbonaceous counterparts obtained by pyrolysis at 900 deg. C. Whereas the latter were, as expected, highly mesoporous carbons, the former cryogels had very different pore textures. Highly diluted cryogels allowed preparation of microporous materials with high surface areas, but activation of initially dense cryogels led to almost non-porous carbons, with much lower surface areas than those obtained by pyrolysis. The optimal acid concentration for activation, corresponding to stoichiometry between molecules of acid and hydroxyl groups, was 2 M l{sup -1}, and the acid-cryogel contact time also had an optimal value. Such optimization allowed us to achieve surface areas and micropore volumes among the highest ever obtained by activation with H{sub 3}PO{sub 4}, close to 2200 m{sup 2} g{sup -1} and 0.7 cm{sup 3} g{sup -1}, respectively. Activation of diluted cryogels with a lower acid concentration of 1.2 M l{sup -1} led to authentic bimodal activated carbons, having a surface area as high as 1780 m{sup 2} g{sup -1} and 0.6 cm{sup 3} g{sup -1} of microporous volume easily accessible through a widely developed macroporosity.

  12. Formaldehyde in the Diffuse Interstellar Cloud MBM40

    Science.gov (United States)

    Joy, Mackenzie; Magnani, Loris A.

    2018-06-01

    MBM40, a high-latitude molecular cloud, has been extensively studied using different molecular tracers. It appears that MBM40 is composed of a relatively dense, helical filament embedded in a more diffuse substrate of low density molecular gas. In order to study the transition between the two regimes, this project presents the first high-resolution mapping of MBM40 using the 110-111 hyperfine transition of formaldehyde (H2CO) at 4.83 GHz. We used H2CO spectra obtained with the Arecibo telescope more than a decade ago to construct this map. The results can be compared to previous maps made from the CO(1-0) transition to gain further understanding of the structure of the cloud. The intensity of the H2CO emission was compared to the CO emission. Although a correlation exists between the H2CO and CO emissivity, there seems to be a saturation of H2CO line strength for stronger CO emissivity. This is probably a radiative transfer effect of the CO emission. We have also found that the velocity dispersion of H2CO in the lower ridge of the cloud is significantly lower than in the rest of the cloud. This may indicate that this portion of the cloud is a coherent structure (analogous to an eddy) in a turbulent flow.

  13. ATM and KAT5 safeguard replicating chromatin against formaldehyde damage

    Science.gov (United States)

    Ortega-Atienza, Sara; Wong, Victor C.; DeLoughery, Zachary; Luczak, Michal W.; Zhitkovich, Anatoly

    2016-01-01

    Many carcinogens damage both DNA and protein constituents of chromatin, and it is unclear how cells respond to this compound injury. We examined activation of the main DNA damage-responsive kinase ATM and formation of DNA double-strand breaks (DSB) by formaldehyde (FA) that forms histone adducts and replication-blocking DNA-protein crosslinks (DPC). We found that low FA doses caused a strong and rapid activation of ATM signaling in human cells, which was ATR-independent and restricted to S-phase. High FA doses inactivated ATM via its covalent dimerization and formation of larger crosslinks. FA-induced ATM signaling showed higher CHK2 phosphorylation but much lower phospho-KAP1 relative to DSB inducers. Replication blockage by DPC did not produce damaged forks or detectable amounts of DSB during the main wave of ATM activation, which did not require MRE11. Chromatin-monitoring KAT5 (Tip60) acetyltransferase was responsible for acetylation and activation of ATM by FA. KAT5 and ATM were equally important for triggering of intra-S-phase checkpoint and ATM signaling promoted recovery of normal human cells after low-dose FA. Our results revealed a major role of the KAT5-ATM axis in protection of replicating chromatin against damage by the endogenous carcinogen FA. PMID:26420831

  14. Effect of Formaldehyde on Human Middle Ear Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Shin Hye Kim

    2018-01-01

    Full Text Available Formaldehyde (FA is a familiar indoor air pollutant found in everything from cosmetics to clothing, but its impact on the middle ear is unknown. This study investigated whether FA causes cytotoxicity, inflammation, or induction of apoptosis in human middle ear epithelial cells (HMEECs. Cell viability was investigated using the trypan blue assay and a cell counting kit (CCK-8 in HMEECs treated with FA for 4 or 24 h. The expression of genes encoding the inflammatory cytokine tumor necrosis factor alpha (TNF-α and mucin (MUC5AC was analyzed using RT-PCR. Activation of the apoptosis pathway was determined by measuring mitochondrial membrane potential (MMP, cytochrome oxidase, caspase-9/Mch6/Apaf 3, and Caspase-Glo® 3/7 activities. The CCK-8 assay and trypan blue assay results showed a reduction in cell viability in FA-treated HMEECs. FA also increased the cellular expression of TNF-α and MUC5AC and reduced the activities of MMP and cytochrome oxidase. Caspase-9 activity increased in cells stimulated for 4 h, as well as caspase-3/7 activity in cells stimulated for 24 h. The decreased cell viability, the induction of inflammation and mucin gene expression, and the activation of the apoptosis pathway together indicate a link between environmental FA exposure and the development of otitis media.

  15. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations; Exposition par inhalation au formaldehyde dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  16. Determination of formaldehyde in frozen fish with formaldehyde dehydrogenase using a flow injection system with an incorporated gel-filtration chromatrography column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ell

    1996-01-01

    in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...

  17. Determination of Formaldehyde in Frozen Fish with Formaldehyde Dehydrogenase Using a Flow Injection System with an Incorporated Gel-filtration Chromatography Column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard

    1996-01-01

    in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...

  18. Study of Necrosis in the Liver of Formaldehyde and Benzo(αPyrene Exposured-Mice

    Directory of Open Access Journals (Sweden)

    Ahmad Soni

    2013-04-01

    Full Text Available Formaldehyde and benzo(αpyrene are compounds that harmful for health. Misapplication of this compound has an impact in the form of organ damage in the body. This study aims to determine the impact of the treatment of the combined exposure of formaldehyde and benzo(αpyrene to cell necrosis in the liver of mice (Mus musculus. Treatment of formaldehyde dose of 25 mg/kg BW to mice was given orally every day for 60 days. Treatment of benzo(αpyrene via intraperitoneal injection at a dose of 250 mg/kg BW were given after 30 days of incubation with four times injection with one day interval. Liver organ histological preparations were made through the HE staining. Observations were made by using a microscope for liver organ preparations. The data obtained that is the percentage of cells necrosis and necrotic foci. This research used Completely Randomized Design (CRD with 95% confidence interval. Liver organ preparations observations indicate that the percentage of necrosis in the untreated control, benzo(αpyrene 250 mg/kg BW, formaldehyde 25 mg/kg BW, combination of formaldehyde 25 mg/kg BW with BaP in a row that is equal to 14.43% ± 0.91; 26.05% ± 3.75; 49.38% ± 2.66; 51.86 ± 1.73. The mean of necrotic foci in liver organ formed in the untreatment control, benzo(αpyrene 250 mg/kg BW, Formaldehyde 25 mg/kg BW, and the combination of formaldehyde 25 mg/kg BW with BaP in a row, equal to 1.3 ± 0,07; 1.63 ± 0.61; 2 ± 0.51, and 3.4 ± 0.76. This suggests that the combined treatment had the highest level of toxicity compared with other treatments.

  19. Regulation characteristics of oxide generation and formaldehyde removal by using volume DBD reactor

    Science.gov (United States)

    Bingyan, CHEN; Xiangxiang, GAO; Ke, CHEN; Changyu, LIU; Qinshu, LI; Wei, SU; Yongfeng, JIANG; Xiang, HE; Changping, ZHU; Juntao, FEI

    2018-02-01

    Discharge plasmas in air can be accompanied by ultraviolet (UV) radiation and electron impact, which can produce large numbers of reactive species such as hydroxyl radical (OH·), oxygen radical (O·), ozone (O3), and nitrogen oxides (NO x ), etc. The composition and dosage of reactive species usually play an important role in the case of volatile organic compounds (VOCs) treatment with the discharge plasmas. In this paper, we propose a volume discharge setup used to purify formaldehyde in air, which is configured by a plate-to-plate dielectric barrier discharge (DBD) channel and excited by an AC high voltage source. The results show that the relative spectral-intensity from DBD cell without formaldehyde is stronger than the case with formaldehyde. The energy efficiency ratios (EERs) of both oxides yield and formaldehyde removal can be regulated by the gas flow velocity in DBD channel, and the most desirable processing effect is the gas flow velocity within the range from 2.50 to 3.33 m s-1. Moreover, the EERs of both the generated dosages of oxides (O3 and NO2) and the amount of removed formaldehyde can also be regulated by both of the applied voltage and power density loaded on the DBD cell. Additionally, the EERs of both oxides generation and formaldehyde removal present as a function of normal distribution with increasing the applied power density, and the peak of the function is appeared in the range from 273.5 to 400.0 W l-1. This work clearly demonstrates the regulation characteristic of both the formaldehyde removal and oxides yield by using volume DBD, and it is helpful in the applications of VOCs removal by using discharge plasma.

  20. Novel silicone-based polymer containing active methylene designed for the removal of indoor formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Song, E-mail: niusong84@163.com; Yan, Hongxia, E-mail: hongxiayan@nwpu.edu.cn

    2015-04-28

    Highlights: • A novel silicone-based polymer with active methylene was explored. • Surface tension of liquid paints could be lowered using the polymer. • The polymer was easy to migrate toward the air-coating interface. • Free HCHO could effectively be removed using the polymer. • A lights on HCHO reduction without complicated preparation procedure was shielded. - Abstract: Indoor air pollution is caused inevitably due to complicated home decoration, in which formaldehyde is one of the most typical pollutants. It will be a convenient, economical and effective strategy to remove indoor formaldehyde if imparting a feature of formaldehyde removal to decorative coatings. We have successfully explored a novel silicone-based polymer containing active methylene used as a formaldehyde absorbent in coatings via a straightforward transesterification process using inexpensive and easily available chemicals. The polymer has been characterized by {sup 13}C NMR, FTIR, GC and GPC. Formaldehyde removal capacity of the coating films containing different contents of the polymer has been investigated. The results indicated that coatings incorporating 4 wt% of the polymer could make the coating films exhibit significant improvement on formaldehyde removal including purificatory performance (>85%) and durability of purificatory effect (>60%), compared to those consisting of absorbents without any silicon, and improve yellowing resistance performance, while other properties, such as gloss, adhesion, pencil hardness, flexibility and impact resistance, were kept almost unaffected. The chemical absorption process of the silicone-based polymer filled in interior decorative coatings is demonstrated as a promising technology to purify indoor formaldehyde and thus can reduce the harm to individuals.

  1. The Australian Work Exposures Study: Prevalence of Occupational Exposure to Formaldehyde.

    Science.gov (United States)

    Driscoll, Timothy R; Carey, Renee N; Peters, Susan; Glass, Deborah C; Benke, Geza; Reid, Alison; Fritschi, Lin

    2016-01-01

    The aims of this study were to produce a population-based estimate of the prevalence of work-related exposure to formaldehyde, to identify the main circumstances of exposure and to describe the use of workplace control measures designed to decrease those exposures. The analysis used data from the Australian Workplace Exposures Study, a nationwide telephone survey, which investigated the current prevalence and exposure circumstances of work-related exposure to 38 known or suspected carcinogens, including formaldehyde, among Australian workers aged 18-65 years. Using the web-based tool OccIDEAS, semi-quantitative information was collected about exposures in the current job held by the respondent. Questions were addressed primarily at tasks undertaken rather than about self-reported exposures. Of the 4993 included respondents, 124 (2.5%) were identified as probably being exposed to formaldehyde in the course of their work [extrapolated to 2.6% of the Australian working population-265 000 (95% confidence interval 221 000-316 000) workers]. Most (87.1%) were male. About half worked in technical and trades occupations. In terms of industry, about half worked in the construction industry. The main circumstances of exposure were working with particle board or plywood typically through carpentry work, building maintenance, or sanding prior to painting; with the more common of other exposures circumstances being firefighters involved in fighting fires, fire overhaul, and clean-up or back-burning; and health workers using formaldehyde when sterilizing equipment or in a pathology laboratory setting. The use of control measures was inconsistent. Workers are exposed to formaldehyde in many different occupational circumstances. Information on the exposure circumstances can be used to support decisions on appropriate priorities for intervention and control of occupational exposure to formaldehyde, and estimates of burden of cancer arising from occupational exposure to formaldehyde

  2. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage.

    Science.gov (United States)

    Yu, Rui; Lai, Yongquan; Hartwell, Hadley J; Moeller, Benjamin C; Doyle-Eisele, Melanie; Kracko, Dean; Bodnar, Wanda M; Starr, Thomas B; Swenberg, James A

    2015-07-01

    Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N(2-)hydroxymethyl-dG (N(2)-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N(2)-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [(13)CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N(2)-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency's Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair. © The Author 2015

  3. Surface modification of bone char for removal of formaldehyde from air

    Energy Technology Data Exchange (ETDEWEB)

    Rezaee, Abbas, E-mail: rezaee@modares.ac.ir [Environmental Health Department, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Rangkooy, Hosseinali [Environmental Health Department, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Occupational Health Department, Faculty of Health, Jondishapor Medical Sciences University, Ahvaz (Iran, Islamic Republic of); Jonidi-Jafari, Ahmad; Khavanin, Ali [Environmental Health Department, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2013-12-01

    The aim of this study was to evaluate the adsorption performance of bone char (BC) modified with acetic acid for formaldehyde removal from polluted air. The porous structure, surface characteristics and functional groups involved in formaldehyde adsorption were determined using the Brunauer–Emmett–Teller (BET) method, scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR), respectively. It was found that the modified BC has a higher specific surface area than the original BC. The maximum surface area of the modified BC was 118.58 m{sup 2}/g. The FTIR spectrum of modified BC indicated that the hydroxyl and carboxyl groups on the BC surface played a significant role in the adsorption of formaldehyde by modified BC. The breakthrough, equilibrium time and adsorption capacity of modified BC were greater than the original BC. Moreover, the results showed that at initial concentrations of 20, 50, 100 and 200 mg/L, the equilibrium times for BC and modified BC were 85, 75, 65 and 45 min and 95, 85, 70 and 50 min, respectively. It seems that the formaldehyde adsorption capacity of modified BC depends on both physical and chemical properties. These results showed that modified BC can be used as an efficient adsorbent for formaldehyde removal.

  4. Migration of formaldehyde from melamine-ware: UK 2008 survey results.

    Science.gov (United States)

    Potter, E L J; Bradley, E L; Davies, C R; Barnes, K A; Castle, L

    2010-06-01

    Fifty melamine-ware articles were tested for the migration of formaldehyde - with hexamethylenetetramine (HMTA) expressed as formaldehyde - to see whether the total specific migration limit (SML(T)) was being observed. The SML(T), given in European Commission Directive 2002/72/EC as amended, is 15 mg kg(-1). Fourier transform-infrared (FT-IR) spectroscopy was carried out on the articles to confirm the plastic type. Articles were exposed to the food simulant 3% (w/v) aqueous acetic acid under conditions representing their worst foreseeable use. Formaldehyde and HMTA in food simulants were determined by a spectrophotometric derivatization procedure. Positive samples were confirmed by a second spectrophotometric procedure using an alternative derivatization agent. As all products purchased were intended for repeat use, three sequential exposures to the simulant were carried out. Formaldehyde was detected in the simulant exposed to 43 samples. Most of the levels found were well below the limits set in law such that 84% of the samples tested were compliant. However, eight samples had formaldehyde levels that were clearly above the legal maximum at six to 65 times the SML(T).

  5. Quantification of Atmospheric Formaldehyde by Near-Infrared Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Rella, C.; Hoffnagle, J.; Fleck, D.; Kim-Hak, D.

    2017-12-01

    Formaldehyde is an important species in atmospheric chemistry, especially in urban environments, where it is a decay product of methane and volatile hydrocarbons. It is also a toxic, carcinogenic compound that can contaminate ambient air from incomplete combustion, or outgassing of commercial products such as adhesives used to fabricate plywood or to affix indoor carpeting. Formaldehyde has a clearly resolved ro-vibrational absorption spectrum that is well-suited to optical analysis of formaldehyde concentration. We describe an instrument based on cavity ring-down spectroscopy for the quantitative analysis of formaldehyde concentration in ambient air. The instrument has a precision (1-sigma) of about 1 ppb at a measurement rate of 1 second, and provides measurements of less than 100 ppt with averaging. The instrument provides stable measurements (drift < 1 ppb) over long periods of time (days). The instrument has been ruggedized for mobile applications, and with a fast response time of a couple of seconds, it is suitable for ground-based vehicle deployments for fenceline monitoring of formaldehyde emissions. In addition, we report on ambient atmospheric measurements at a 10m urban tower, which demonstrate the suitability of the instrument for applications in atmospheric chemistry.

  6. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents

    Directory of Open Access Journals (Sweden)

    Mirella Gutiérrez-Arzaluz

    2016-05-01

    Full Text Available We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation methods do not work for formaldehyde, a highly toxic but refractory, low biodegradability substance. The CWO reaction is a recent, promising alternative that also permits much lower temperature and pressure conditions than other oxidation processes, resulting in economic benefits. The CWO reaction employing Ce- and Co-containing catalysts was carried out inside a slurry batch reactor and a membrane reactor. Experimental results are reported. Next, a mixed Ce–Co oxide film was supported on an γ-alumina membrane used in a catalytic membrane reactor to compare formaldehyde removal between both types of systems. Catalytic materials with cerium and with a relatively large amount of cerium favored the transformation of formaldehyde. Cerium was present as cerianite in the catalytic materials, as indicated by X-ray diffraction patterns.

  7. EXPLORING THE POTENTIAL FORMATION OF ORGANIC SOLIDS IN CHONDRITES AND COMETS THROUGH POLYMERIZATION OF INTERSTELLAR FORMALDEHYDE

    International Nuclear Information System (INIS)

    Kebukawa, Yoko; Cody, George D.; David Kilcoyne, A. L.

    2013-01-01

    Polymerization of interstellar formaldehyde, first through the formose reaction and then through subsequent condensation reactions, provides a plausible explanation for how abundant and highly chemically complex organic solids may have come to exist in primitive solar system objects. In order to gain better insight on the reaction, a systematic study of the relationship of synthesis temperature with resultant molecular structure was performed. In addition, the effect of the presence of ammonia on the reaction rate and molecular structure of the product was studied. The synthesized formaldehyde polymer is directly compared to chondritic insoluble organic matter (IOM) isolated from primitive meteorites using solid-state 13 C nuclear magnetic resonance, Fourier transform infrared, and X-ray absorption near edge structure spectroscopy. The molecular structure of the formaldehyde polymer is shown to exhibit considerable similarity at the functional group level with primitive chondritic IOM. The addition of ammonia to the solution enhances the rate of polymerization reaction at lower temperatures and results in substantial incorporation of nitrogen into the polymer. Morphologically, the formaldehyde polymer exists as submicron to micron-sized spheroidal particles and spheroidal particle aggregates that bare considerable similarity to the organic nanoglobules commonly observed in chondritic IOM. These spectroscopic and morphological data support the hypothesis that IOM in chondrites and refractory organic carbon in comets may have formed through the polymerization of interstellar formaldehyde after planetesimal accretion, in the presence of liquid water, early in the history of the solar system.

  8. EXPLORING THE POTENTIAL FORMATION OF ORGANIC SOLIDS IN CHONDRITES AND COMETS THROUGH POLYMERIZATION OF INTERSTELLAR FORMALDEHYDE

    Energy Technology Data Exchange (ETDEWEB)

    Kebukawa, Yoko; Cody, George D. [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC 20015 (United States); David Kilcoyne, A. L., E-mail: ykebukawa@ciw.edu, E-mail: yoko@ep.sci.hokudai.ac.jp [Advanced Light Source, Lawrence Berkeley National Laboratory, Mail Stop 7R0222, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

    2013-07-01

    Polymerization of interstellar formaldehyde, first through the formose reaction and then through subsequent condensation reactions, provides a plausible explanation for how abundant and highly chemically complex organic solids may have come to exist in primitive solar system objects. In order to gain better insight on the reaction, a systematic study of the relationship of synthesis temperature with resultant molecular structure was performed. In addition, the effect of the presence of ammonia on the reaction rate and molecular structure of the product was studied. The synthesized formaldehyde polymer is directly compared to chondritic insoluble organic matter (IOM) isolated from primitive meteorites using solid-state {sup 13}C nuclear magnetic resonance, Fourier transform infrared, and X-ray absorption near edge structure spectroscopy. The molecular structure of the formaldehyde polymer is shown to exhibit considerable similarity at the functional group level with primitive chondritic IOM. The addition of ammonia to the solution enhances the rate of polymerization reaction at lower temperatures and results in substantial incorporation of nitrogen into the polymer. Morphologically, the formaldehyde polymer exists as submicron to micron-sized spheroidal particles and spheroidal particle aggregates that bare considerable similarity to the organic nanoglobules commonly observed in chondritic IOM. These spectroscopic and morphological data support the hypothesis that IOM in chondrites and refractory organic carbon in comets may have formed through the polymerization of interstellar formaldehyde after planetesimal accretion, in the presence of liquid water, early in the history of the solar system.

  9. Exploring the Potential Formation of Organic Solids in Chondrites and Comets through Polymerization of Interstellar Formaldehyde

    Science.gov (United States)

    Kebukawa, Yoko; Kilcoyne, A. L. David; Cody, George D.

    2013-07-01

    Polymerization of interstellar formaldehyde, first through the formose reaction and then through subsequent condensation reactions, provides a plausible explanation for how abundant and highly chemically complex organic solids may have come to exist in primitive solar system objects. In order to gain better insight on the reaction, a systematic study of the relationship of synthesis temperature with resultant molecular structure was performed. In addition, the effect of the presence of ammonia on the reaction rate and molecular structure of the product was studied. The synthesized formaldehyde polymer is directly compared to chondritic insoluble organic matter (IOM) isolated from primitive meteorites using solid-state 13C nuclear magnetic resonance, Fourier transform infrared, and X-ray absorption near edge structure spectroscopy. The molecular structure of the formaldehyde polymer is shown to exhibit considerable similarity at the functional group level with primitive chondritic IOM. The addition of ammonia to the solution enhances the rate of polymerization reaction at lower temperatures and results in substantial incorporation of nitrogen into the polymer. Morphologically, the formaldehyde polymer exists as submicron to micron-sized spheroidal particles and spheroidal particle aggregates that bare considerable similarity to the organic nanoglobules commonly observed in chondritic IOM. These spectroscopic and morphological data support the hypothesis that IOM in chondrites and refractory organic carbon in comets may have formed through the polymerization of interstellar formaldehyde after planetesimal accretion, in the presence of liquid water, early in the history of the solar system.

  10. A Potentiometric Formaldehyde Biosensor Based on Immobilization of Alcohol Oxidase on Acryloxysuccinimide-modified Acrylic Microspheres

    Directory of Open Access Journals (Sweden)

    Lee Yook Heng

    2010-11-01

    Full Text Available A new alcohol oxidase (AOX enzyme-based formaldehyde biosensor based on acrylic microspheres has been developed. Hydrophobic poly(n-butyl acrylate-N-acryloxy-succinimide [poly(nBA-NAS] microspheres, an enzyme immobilization matrix, was synthesized using photopolymerization in an emulsion form. AOX-poly(nBA-NAS microspheres were deposited on a pH transducer made from a layer of photocured and self-plasticized polyacrylate membrane with an entrapped pH ionophore coated on a Ag/AgCl screen printed electrode (SPE. Oxidation of formaldehyde by the immobilized AOX resulted in the production of protons, which can be determined via the pH transducer. Effects of buffer concentrations, pH and different amount of immobilization matrix towards the biosensor’s analytical performance were investigated. The formaldehyde biosensor exhibited a dynamic linear response range to formaldehyde from 0.3–316.2 mM and a sensitivity of 59.41 ± 0.66 mV/decade (R2 = 0.9776, n = 3. The lower detection limit of the biosensor was 0.3 mM, while reproducibility and repeatability were 3.16% RSD (relative standard deviation and 1.11% RSD, respectively (n = 3. The use of acrylic microspheres in the potentiometric formaldehyde biosensor improved the biosensor’s performance in terms of response time, linear response range and long term stability when compared with thick film immobilization methods.

  11. Effects of a single inhalative exposure to formaldehyde on the open field behavior of mice.

    Science.gov (United States)

    Malek, Fathi A; Möritz, Klaus-Uwe; Fanghänel, Jochen

    2004-02-01

    The effects of formaldehyde on the explorative behavior and locomotor activity of mice after a single inhalative exposure were examined in an open field. Adult male mice were exposed to approximately 1.1 ppm, 2.3 ppm, or 5.2 ppm formaldehyde vapour for 2 hours and the open field test was carried out two hours after the end of exposure (trial 1) and repeated 24 hours thereafter (trial 2). The following behavioral parameters were quantitatively examined: numbers of crossed floor squares (inner, peripheral, total), sniffing, grooming, rearing, climbing, and incidence of fecal boli. The results of the first trial revealed that the motion activity was significantly reduced in all exposed groups. In the 1.1 ppm group, the frequency of rearing was reduced and that of floor sniffing increased. The exposure to the two higher formaldehyde concentrations caused a significant decrease in total numbers of floor squares crossed by the subjects, air sniffing, and rearing. The open field test on the next day (trial 2) showed that the frequencies of floor sniffing, grooming, and rearing in all formaldehyde groups were significantly altered. In the 2.5 ppm group, an increased incidence of fecal boli was observed. From the results obtained, we conclude that the exposure of male mice to formaldehyde vapour affects their locomotor and explorative activity in the open field, and that some open field parameters are still altered in the exposed animals even after 24 hours.

  12. Formaldehyde Crosses the Human Placenta and Affects Human Trophoblast Differentiation and Hormonal Functions.

    Directory of Open Access Journals (Sweden)

    Guillaume Pidoux

    Full Text Available The chorionic villus of the human placenta is the source of specific endocrine functions and nutrient exchanges. These activities are ensured by the syncytiotrophobast (ST, which bathes in maternal blood. The ST arises and regenerates throughout pregnancy by fusion of underlying cytotrophoblasts (CT. Any anomaly of ST formation or regeneration can affect pregnancy outcome and fetal growth. Because of its direct interaction with maternal blood, the ST is sensitive to drugs, pollutants and xenohormones. Ex vivo assays of perfused cotyledon show that formaldehyde, a common pollutant present in furniture, paint and plastics, can accumulate in the human placenta and cross to the fetal compartment. By means of RT-qPCR, immunoblot and immunocytochemistry experiments, we demonstrate in vitro that formaldehyde exerts endocrine toxicity on human trophoblasts, including a decrease in the production of protein hormones of pregnancy. In addition, formaldehyde exposure triggered human trophoblast fusion by upregulating syncitin-1 receptor expression (ASC-type amino-acid transporter 2: ASCT2. Moreover, we show that formaldehyde-exposed trophoblasts present an altered redox status associated with oxidative stress, and an increase in ASCT2 expression intended to compensate for this stress. Finally, we demonstrate that the adverse effects of formaldehyde on trophoblast differentiation and fusion are reversed by N-acetyl-L-cysteine (Nac, an antioxidant.

  13. Gas-diffusion microextraction coupled with spectrophotometry for the determination of formaldehyde in cork agglomerates.

    Science.gov (United States)

    Brandão, Pedro F; Ramos, Rui M; Valente, Inês M; Almeida, Paulo J; Carro, Antonia M; Lorenzo, Rosa A; Rodrigues, José A

    2017-04-01

    In this work, a simple methodology was developed for the extraction and determination of free formaldehyde content in cork agglomerate samples. For the first time, gas-diffusion microextraction was used for the extraction of volatile formaldehyde directly from samples, with simultaneous derivatization with acetylacetone (Hantzsch reaction). The absorbance of the coloured solution was read in a spectrophotometer at 412 nm. Different extraction parameters were studied and optimized (extraction temperature, sample mass, volume of acceptor solution, extraction time and concentration of derivatization reagent) by means of an asymmetric screening. The developed methodology proved to be a reliable tool for the determination of formaldehyde in cork agglomerates with the following suitable method features: low LOD (0.14 mg kg -1 ) and LOQ (0.47 mg kg -1 ), r 2  = 0.9994, and intraday and interday precision of 3.5 and 4.9%, respectively. The developed methodology was applied to the determination of formaldehyde in different cork agglomerate samples, and contents between 1.9 and 9.4 mg kg -1 were found. Furthermore, formaldehyde was also determined by the standard method EN 717-3 for comparison purposes; no significant differences between the results of both methods were observed. Graphical abstract Representation of the GDME system and its main components.

  14. Isotopic separation of 13C by selective photodissociation of formaldehyde

    International Nuclear Information System (INIS)

    Mussillon, T.

    1998-01-01

    The aim of this work is to study the feasibility of the 13 C isotopic separation by UV laser spectroscopy. The spectra of H 2 12 CO and H 2 13 CO have been recorded by a Fourier transform spectrometer between 28000 and 34000 cm -1 . From these data has been carried out a systematic study of some lines by laser spectroscopy. The selectivity measurements have been compared with the obtained enrichment factors. Thus has been revealed in a quantitative way, the importance of the isotopic re-mixture phenomena and of the selectivity loss. The best enrichment factor has been measured at 29935,56 cm -1 (band: (2,14,1)). A final percentage of 42,1 % has been obtained in a reproducible way for 13 C. The evolution of the enrichment factor has been characterized for a pressure range between 4,4 and 43 mbar. Above the radical dissociation threshold, it has not be possible to show a positive effect of NO on the enrichment factor. This negative result has been explained by a detailed kinetic study of the radical reactions (available literature). This experimental study has been completed by a bibliographic synthesis for understanding the formaldehyde photochemistry. All the processes able to influence the performance of this isotopic separation process have been gathered in this work in an exhaustive way. The radical dissociation threshold of H 2 13 CO have been calculated from molecular constants of the literature and from known thermodynamic data for H 2 12 CO. (O.M.)

  15. Determination of free formaldehyde in cosmetics containing formaldehyde-releasing preservatives by reversed-phase dispersive liquid-liquid microextraction and liquid chromatography with post-column derivatization.

    Science.gov (United States)

    Miralles, Pablo; Chisvert, Alberto; Alonso, M José; Hernandorena, Sandra; Salvador, Amparo

    2018-03-30

    An analytical method for the determination of traces of formaldehyde in cosmetic products containing formaldehyde-releasing preservatives has been developed. The method is based on reversed-phase dispersive liquid-liquid microextraction (RP-DLLME), that allows the extraction of highly polar compounds, followed by liquid chromatography-ultraviolet/visible (LC-UV/vis) determination with post-column derivatization. The variables involved in the RP-DLLME process were studied to provide the best enrichment factors. Under the selected conditions, a mixture of 500 μL of acetonitrile (disperser solvent) and 50 μL of water (extraction solvent) was rapidly injected into 5 mL of toluene sample solution. The extracts were injected into the LC-UV/vis system using phosphate buffer 6 mmol L -1 at pH 2 as mobile phase. After chromatographic separation, the eluate merged with a flow stream of pentane-2,4-dione in ammonium acetate solution as derivatizing reagent and passed throughout a post-column reactor at 85 °C in order to derivatize formaldehyde into 3,5-diacetyl-1,4-dihydrolutidine, according to Hantzsch reaction, which was finally measured spectrophotometrically at 407 nm. The method was successfully validated showing good linearity, an enrichment factor of 86 ± 2, limits of detection and quantification of 0.7 and 2.3 ng mL -1 , respectively, and good repeatability (RSD < 9.2%). Finally, the proposed analytical method was applied to the determination of formaldehyde in different commercial cosmetic samples containing formaldehyde-releasing preservatives, such as bronopol, diazolidinyl urea, imidazolidinyl urea, and DMDM hydantoin, with good relative recovery values (91-113%) thus showing that matrix effects were negligible. The good analytical features of the proposed method besides of its simplicity and affordability, make it useful to carry out the quality control of cosmetic products containing formaldehyde-releasing preservatives. Copyright

  16. RELATION BETWEEN MECHANICAL PROPERTIES AND PYROLYSIS TEMPERATURE OF PHENOL FORMALDEHYDE RESIN FOR GAS SEPARATION MEMBRANES

    Directory of Open Access Journals (Sweden)

    MONIKA ŠUPOVÁ

    2012-03-01

    Full Text Available The aim of this paper has been to characterize the relation between the pyrolysis temperature of phenol-formaldehyde resin, the development of a porous structure, and the mechanical properties for the application of semipermeable membranes for gas separation. No previous study has dealt with this problem in its entirety. Phenol-formaldehyde resin showed an increasing trend toward micropore porosity in the temperature range from 500 till 1000°C, together with closure of mesopores and macropores. Samples cured and pyrolyzed at 1000°C pronounced hysteresis of desorption branch. The ultimate bending strength was measured using a four-point arrangement that is more suitable for measuring of brittle materials. The chevron notch technique was used for determination the fracture toughness. The results for mechanical properties indicated that phenol-formaldehyde resin pyrolyzates behaved similarly to ceramic materials. The data obtained for the material can be used for calculating the technical design of gas separation membranes.

  17. Formaldehyde-induced mutations in Drosophila melanogaster in dependence of the presence of acids

    Energy Technology Data Exchange (ETDEWEB)

    Stumm-Tegethoff, B F.A.

    1969-01-01

    The mutagenic activity of various combinations of formaldehyde, formic acid, acetic acid and hydrochloric acid was investigated by a sex-linked lethal test. All combinations were mutagenic and showed a mutation pattern from which it is concluded that in feeding experiments spermatocytes I are especially sensitive to the pairs of chemicals tested. In vapour experiments all germ cell stages were found to be susceptible. The presence of volatile acids was found to be necessary for the mutagenic activity of formaldehyde in the vapour state. Mutagenic effects were also observed in larval feeding experiments, in which only these acids were added to the medium. Experiments with stabilized pH at 7.5 did not show a significant mutagenic effect of formaldehyde. It is postulated that the tested agents are catalase inhibitors, which promote the formation of peroxides or free radicals which interfere with DNA replication, thus producing mutations.

  18. Solid-state /sup 13/C NMR study of cured resorcinol-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    Lippmaa, H.; Samoson, A.

    1988-08-01

    The curing process generally follows the pattern observed in the stage of prepolymer formation. Catalysts (NaOH, hexa, Mg(OCOCH/sub 3/)/sub 2/) that have no substantial influence on the isomeric composition of the resorcinol-formaldehyde prepolymers, do not affect the isomeric composition of the cured resins to any significant extent either. Isomeric composition of the cured resins depends mostly on the presence of water during the curing process, necessary for depolymerisation of the added paraformaldehyde. Curing in the melt leads to enhanced 2-substitution in the 1,3-dihydroxybenzene rings. In the /sup 13/C NMR spectra of cured powdered samples, the tendency of 5-methylresorcinol to form oligomers with a higher degree of 2-substitution than resorcinol is clearly apparent. Polycondensation process continues in the powdered resins after initial curing until complete consumption of all formaldehyde. Curing of phenol-formaldehyde resols proceeds through intermediate dimethylene ether formation.

  19. First direct measurements of formaldehyde flux via eddy covariance: implications for missing in-canopy formaldehyde sources

    Directory of Open Access Journals (Sweden)

    J. P. DiGangi

    2011-10-01

    Full Text Available We report the first observations of formaldehyde (HCHO flux measured via eddy covariance, as well as HCHO concentrations and gradients, as observed by the Madison Fiber Laser-Induced Fluorescence Instrument during the BEACHON-ROCS 2010 campaign in a rural, Ponderosa Pine forest northwest of Colorado Springs, CO. A median noon upward flux of ~80 μg m−2 h−1 (~24 pptv m s−1 was observed with a noon range of 37 to 131 μg m−2 h−1. Enclosure experiments were performed to determine the HCHO branch (3.5 μg m-2 h−1 and soil (7.3 μg m−2 h−1 direct emission rates in the canopy. A zero-dimensional canopy box model, used to determine the apportionment of HCHO source and sink contributions to the flux, underpredicted the observed HCHO flux by a factor of 6. Simulated increases in concentrations of species similar to monoterpenes resulted in poor agreement with measurements, while simulated increases in direct HCHO emissions and/or concentrations of species similar to 2-methyl-3-buten-2-ol best improved model/measurement agreement. Given the typical diurnal variability of these BVOC emissions and direct HCHO emissions, this suggests that the source of the missing flux is a process with both a strong temperature and radiation dependence.

  20. 40 CFR 721.6181 - Fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl ether...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid, reaction product with... Specific Chemical Substances § 721.6181 Fatty acid, reaction product with substituted oxirane, formaldehyde... as fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl ether...

  1. 40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Gas meter or flow instrumentation... Procedures § 86.120-94 Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions requires the use of gas meters...

  2. Effects of Endogenous Formaldehyde in Nasal Tissues on Inhaled Formmaldehyde Dosimetry Predictions in the Rat, Monkey, and Human Nasal Passages

    Science.gov (United States)

    ABSTRACT Formaldehyde, a nasal carcinogen, is also an endogenous compound that is present in all living cells. Due to its high solubility and reactivity, quantitative risk estimates for inhaled formaldehyde rely on internal dose calculations in the upper respiratory tract which ...

  3. Health Risk Assessment of Inhalation Exposure to Formaldehyde and Benzene in Newly Remodeled Buildings, Beijing

    Science.gov (United States)

    Huang, Lihui; Mo, Jinhan; Sundell, Jan; Fan, Zhihua; Zhang, Yinping

    2013-01-01

    Objective To assess health risks associated with inhalation exposure to formaldehyde and benzene mainly emitted from building and decoration materials in newly remodeled indoor spaces in Beijing. Methods We tested the formaldehyde and benzene concentrations in indoor air of 410 dwellings and 451 offices remodeled within the past year, in which the occupants had health concerns about indoor air quality. To assess non-carcinogenic health risks, we compared the data to the health guidelines in China and USA, respectively. To assess carcinogenic health risks, we first modeled indoor personal exposure to formaldehyde and benzene using the concentration data, and then estimated the associated cancer risks by multiplying the indoor personal exposure by the Inhalation Unit Risk values (IURs) provided by the U.S. EPA Integrated Risk Information System (U.S. EPA IRIS) and the California Office of Environmental Health Hazard Assessment (OEHHA), respectively. Results (1) The indoor formaldehyde concentrations of 85% dwellings and 67% offices were above the acute Reference Exposure Level (REL) recommended by the OEHHA and the concentrations of all tested buildings were above the chronic REL recommended by the OEHHA; (2) The indoor benzene concentrations of 12% dwellings and 32% offices exceeded the reference concentration (RfC) recommended by the U.S. EPA IRIS; (3) The median cancer risks from indoor exposure to formaldehyde and benzene were 1,150 and 106 per million (based on U.S. EPA IRIS IURs), 531 and 394 per million (based on OEHHA IURs). Conclusions In the tested buildings, formaldehyde exposure may pose acute and chronic non-carcinogenic health risks to the occupants, whereas benzene exposure may pose chronic non-carcinogenic risks to the occupants. Exposure to both compounds is associated with significant carcinogenic risks. Improvement in ventilation, establishment of volatile organic compounds (VOCs) emission labeling systems for decorating and refurbishing materials

  4. Formaldehyde-related clinical symptoms reported by medical students during gross anatomy cadaver dissection

    Directory of Open Access Journals (Sweden)

    Łukasz Pietrzyk

    2016-09-01

    Full Text Available Introduction . Formaldehyde is a noxious gas used as a tissue preservative of cadavers in autopsy rooms. Therefore, exposure to higher concentrations applies particularly to laboratory staff, anatomists and medical students. Prolonged exposure to formaldehyde is associated with clinical complications. Objective. To assess whether exposure to repeated inhalation of low concentrations of formaldehyde (FA experienced during a gross anatomy course triggers subjective clinical symptoms in medical students. Material and methods . All 198 first-year medical students of the Medical University of Lublin, Poland (28% with allergy history and 72% without allergy history; 69% male and 31% female responded to a questionnaire concerning their subjective FA-related clinical symptoms. Differences in proportions of experienced symptoms between allergic vs. nonallergic, and female vs. males were compared by the Mann-Whitney U test. Results . Even though formaldehyde concentrations in the gross anatomy laboratory were relatively low (0.47–0.57 mg/m3, medical students experienced various reactions (lacrimation in 85.9%, red eyes, dry and itchy eyes, runny nose, sneezing, and headache in > 50% of students, cough in 44%, and dry throat or throat irritation in 42% of students. Among students with a history of allergy, eye, nose, skin and respiratory system symptoms occurred more frequently in comparison to nonallergic students. Female individuals demonstrated higher sensitivity to FA exposure. Conclusions . Exposure to formaldehyde may result in development of clinical symptoms in medical students. Particularly unpleasant symptoms may be experienced by individuals with allergy history. It is necessary to decrease formaldehyde concentrations in the anatomy dissection laboratory.

  5. Treatment of marine sewage pumpout and RV park pumpout wastewater containing high strength concentrations of formaldehyde

    International Nuclear Information System (INIS)

    Salonich, J.

    2002-01-01

    'Full text:' A consortium of companies has developed an integrated 'on-site' wastewater treatment technology that is capable of handling and degrading RV Park and Marine Sewage Pumpout Wastes which contain formaldehyde [35 - 80 mg/L]. Boat and RV owners add formaldehyde to their toilets to eliminate odors. When these materials are pumped out they are high in solids content and have high concentrations of HCHO, which makes them difficult to degrade at POTWs. At the heart of this process is 1. An aeration tank with a Venturi Aerator totally external to the tank and 2. The addition of a blend of cultured bacteria that have selected for their ability to degrade formaldehyde. For a complete 'on-site' treatment system Bioclere Trickling Filters can follow this aeration/bacterial treatment system. This is an ideal system configuration for remote locations (RV Parks) or for fresh water lake Marinas looking to reduce their disposal costs and for groundwater discharge with no adverse effect on water quality. Until the development of the formaldehyde degrading bacteria for an industrial wastewater process there were no cultures commercially available specifically for degrading formaldehyde. The most commonly used bacteria were pseudomonas strains for carbohydrate or hydrocarbon wastewater extracted from activated sludge plants. And since formaldehyde is infinitely soluble in a liquid it is difficult to degrade or mineralize. The process in an activated sludge WWTP plant took over 72 hours. With the newly selected consortia of cultures, HCHO can be degraded in 12-14 hours on a batch basis. This is accomplished in a uniquely configured aeration tank where the 'environment' of the tank is constantly conditioned by a Venturi Aerator which strips carbon dioxide generated by the aerobes to maintain a neutral pH, and provide high levels of DO (>5.0 mg/L) to keep the process aerobic. (author)

  6. Biodegradation of formaldehyde from contaminated air using a laboratory scale static-bed bioreactor

    Directory of Open Access Journals (Sweden)

    Yaghoub Hajizadeh

    2014-01-01

    Full Text Available Aims: The objective of the present study was to evaluate the performance of an aerobic fixed-bed bioreactor (FBR enriched with microorganisms of sewage sludge in biodegradation of formaldehyde in air stream with various retention times and airflow rates in laboratory scale. Materials and Methods: An aerobic biofilter 60 cm in height and 14 cm internal diameter made of steel was constructed and packed with a mixture of pumice and compost as a medium and utilized in this study. The microorganism′s growth, which is derived from the sludge of a municipal wastewater treatment plant, was initiated by adding nutrient. During the first few days of run, the airflow containing different concentrations of formaldehyde (from 24 ± 3 to 224 ± 5 mg/m 3 was introduced to the reactor to ensure biological adaptation. Sampling was performed through a series of two impingers containing adsorbent, and analyzed by chromotropic acid assay using DR-5000. Results: The maximum removal and elimination capacity of formaldehyde was yielded at 0.48 ± 0.06 g/m 3 /h inlet loading rate and 180 s of empty bed retention time (EBRT. These values for stabilized days were almost 88% and 0.42 g/m 3 /h, respectively. Conclusion: The results showed that by increasing the inlet concentration of formaldehyde and reducing the EBRT, the formaldehyde removal capacity of the system decreases. Aerobic bioreactor with appropriate bed volume and compatible with inlet pollutant mass flow rate in optimum retention time will admissibly degrade and reduce the formaldehyde concentration from contaminated gas phase, such as gases produced in municipal wastewater treatment facilities.

  7. Migration of formaldehyde and melamine monomers from kitchen- and tableware made of melamine plastic

    DEFF Research Database (Denmark)

    Lund, K.H.; Petersen, J.H.

    2006-01-01

    Migration of one or both formaldehyde and/or melamine monomers was found in seven of ten tested melamine samples bought on the Danish market. The samples were a bowl, a jug, a mug, a ladle, and different cups and plates. No violation of the European Union-specific migration limits for melamine (30...... mg kg(-1)) and formaldehyde (15 mg kg(-1)) was found after three successive exposures to the food stimulant 3% acetic acid after 2 h at 70 degrees C. To investigate the effects of long-term use, migration tests were performed with two types of cups from a day nursery. Furthermore, medium-term use...

  8. The Formation of Formaldehyde on Interstellar Carbonaceous Grain Analogs by O/H Atom Addition

    Energy Technology Data Exchange (ETDEWEB)

    Potapov, Alexey; Jäger, Cornelia [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Henning, Thomas [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Jonusas, Mindaugas; Krim, Lahouari, E-mail: alexey.potapov@uni-jena.de [Department of Chemistry, Sorbonne Universités, UPMC Univ Paris 06, UMR 8233, MONARIS, Paris F-75005 (France)

    2017-09-10

    An understanding of possible scenarios for the formation of astrophysically relevant molecules, particularly complex organic molecules, will bring us one step closer to the understanding of our astrochemical heritage. In this context, formaldehyde is an important molecule as a precursor of methanol, which in turn is a starting point for the formation of more complex organic species. In the present experiments, for the first time, following the synthesis of CO, formaldehyde has been produced on the surface of interstellar grain analogs, hydrogenated fullerene-like carbon grains, by O and H atom bombardment. The formation of H{sub 2}CO is an indication for a possible methanol formation route in such systems.

  9. Mechanistic and dose considerations for supporting adverse pulmonary physiology in response to formaldehyde

    International Nuclear Information System (INIS)

    Thompson, Chad M.; Subramaniam, Ravi P.; Grafstroem, Roland C.

    2008-01-01

    Induction of airway hyperresponsiveness and asthma from formaldehyde inhalation exposure remains a debated and controversial issue. Yet, recent evidences on pulmonary biology and the pharmacokinetics and toxicity of formaldehyde lend support for such adverse effects. Specifically, altered thiol biology from accelerated enzymatic reduction of the endogenous bronchodilator S-nitrosoglutathione and pulmonary inflammation from involvement of Th2-mediated immune responses might serve as key events and cooperate in airway pathophysiology. Understanding what role these mechanisms play in various species and lifestages (e.g., child vs. adult) could be crucial for making more meaningful inter- and intra-species dosimetric extrapolations in human health risk assessment

  10. Behavioral sensitization after repeated formaldehyde exposure in rats.

    Science.gov (United States)

    Sorg, B A; Hochstatter, T

    1999-01-01

    Multiple chemical sensitivity (MCS) is a phenomenon whereby individuals report increased sensitivity to chemicals in the environment, and attribute their sensitivities to prior exposure to the same or often structurally unrelated chemicals. A leading hypothesis suggests that MCS is akin to behavioral sensitization observed in rodents after repeated exposure to drugs of abuse or environmental stressors. Sensitization occurring within limbic circuitry of the central nervous system (CNS) may explain the multisymptom complaints in individuals with MCS. The present studies represent the continuing development of an animal model for MCS, the basis of which is the CNS sensitization hypothesis. Three behaviors were assessed in rats repeatedly exposed to formaldehyde (Form) inhalation. In the first series of experiments, rats were given high-dose Form exposure (11 parts per million [ppm]; 1 h/day x 7 days) or low-dose Form exposure (1 ppm; either 1 h/day x 7 days or 1 h/day x 5 days/week x 4 weeks). Within a few days after discontinuing daily Form, cocaine-induced locomotor activity was elevated after high-dose Form or 20 days of low-dose Form inhalation. Approximately 1 month later, cocaine-induced locomotor activity remained significantly elevated in the 20-day Form-exposed rats. The second experiment assessed whether prior exposure to Form (20 days, as above) would alter the ability to condition to an odor (orange oil) paired with footshock. The results suggested a tendency to increase the conditioned fear response to the odor but not the context of the footshock box, and a decreased tendency to extinguish the conditioned fear response to odor. The third experiment examined whether CNS sensitization to daily cocaine or stress would alter subsequent avoidance responding to odor (Form). Daily cocaine significantly elevated approach responses to Form, while daily stress pretreatment produced a trend in the opposite direction, producing greater avoidance of Form. Preliminary

  11. Genotoxic damage in pathology anatomy laboratory workers exposed to formaldehyde

    International Nuclear Information System (INIS)

    Costa, Solange; Coelho, Patricia; Costa, Carla; Silva, Susana; Mayan, Olga; Silva Santos, Luis; Gaspar, Jorge; Teixeira, Joao Paulo

    2008-01-01

    Formaldehyde (FA) is a chemical traditionally used in pathology and anatomy laboratories as a tissue preservative. Several epidemiological studies of occupational exposure to FA have indicated an increased risk of nasopharyngeal cancers in industrial workers, embalmers and pathology anatomists. There is also a clear evidence of nasal squamous cell carcinomas from inhalation studies in the rat. The postulated mode of action for nasal tumours in rats was considered biologically plausible and considered likely to be relevant to humans. Based on the available data IARC, the International Agency for Research on Cancer, has recently classified FA as a human carcinogen. Although the in vitro genotoxic as well as the in vivo carcinogenic potentials of FA are well documented in mammalian cells and in rodents, evidence for genotoxic effects and carcinogenic properties in humans is insufficient and conflicting thus remains to be more documented. To evaluate the genetic effects of long-term occupational exposure to FA a group of 30 Pathological Anatomy laboratory workers was tested for a variety of biological endpoints, cytogenetic tests (micronuclei, MN; sister chromatid exchange, SCE) and comet assay. The level of exposure to FA was evaluated near the breathing zone of workers, time weighted average of exposure was calculated for each subject. The association between the biomarkers and polymorphic genes of xenobiotic metabolising and DNA repair enzymes was also assessed. The mean level of exposure was 0.44 ± 0.08 ppm (0.04-1.58 ppm). MN frequency was significantly higher (p = 0.003) in the exposed subjects (5.47 ± 0.76) when compared with controls (3.27 ± 0.69). SCE mean value was significantly higher (p < 0.05) among the exposed group (6.13 ± 0.29) compared with control group (4.49 ± 0.16). Comet assay data showed a significant increase (p < 0.05) of TL in FA-exposed workers (60.00 ± 2.31) with respect to the control group (41.85 ± 1.97). A positive correlation was

  12. FORMALDEHYDE MASERS: EXCLUSIVE TRACERS OF HIGH-MASS STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Araya, E. D.; Brown, J. E. [Western Illinois University, Physics Department, 1 University Circle, Macomb, IL 61455 (United States); Olmi, L. [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Ortiz, J. Morales [University of Puerto Rico, Río Piedras Campus, Physical Sciences Department, P.O. Box 23323, San Juan, PR 00931 (United States); Hofner, P.; Creech-Eakman, M. J. [New Mexico Institute of Mining and Technology, Physics Department, 801 Leroy Place, Socorro, NM 87801 (United States); Kurtz, S. [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apdo. Postal 3-72, 58089 Morelia, Michoacán (Mexico); Linz, H. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)

    2015-11-15

    The detection of four formaldehyde (H{sub 2}CO) maser regions toward young high-mass stellar objects in the last decade, in addition to the three previously known regions, calls for an investigation of whether H{sub 2}CO masers are an exclusive tracer of young high-mass stellar objects. We report the first survey specifically focused on the search for 6 cm H{sub 2}CO masers toward non high-mass star-forming regions (non HMSFRs). The observations were conducted with the 305 m Arecibo Telescope toward 25 low-mass star-forming regions, 15 planetary nebulae and post-AGB stars, and 31 late-type stars. We detected no H{sub 2}CO emission in our sample of non HMSFRs. To check for the association between high-mass star formation and H{sub 2}CO masers, we also conducted a survey toward 22 high-mass star-forming regions from a Hi-GAL (Herschel infrared Galactic Plane Survey) sample known to harbor 6.7 GHz CH{sub 3}OH masers. We detected a new 6 cm H{sub 2}CO emission line in G32.74−0.07. This work provides further evidence that supports an exclusive association between H{sub 2}CO masers and young regions of high-mass star formation. Furthermore, we detected H{sub 2}CO absorption toward all Hi-GAL sources, and toward 24 low-mass star-forming regions. We also conducted a simultaneous survey for OH (4660, 4750, 4765 MHz), H110α (4874 MHz), HCOOH (4916 MHz), CH{sub 3}OH (5005 MHz), and CH{sub 2}NH (5289 MHz) toward 68 of the sources in our sample of non HMSFRs. With the exception of the detection of a 4765 MHz OH line toward a pre-planetary nebula (IRAS 04395+3601), we detected no other spectral line to an upper limit of 15 mJy for most sources.

  13. Two-photon imaging of formaldehyde in live cells and animals utilizing a lysosome-targetable and acidic pH-activatable fluorescent probe.

    Science.gov (United States)

    Xie, Xilei; Tang, Fuyan; Shangguan, Xiaoyan; Che, Shiyi; Niu, Jinye; Xiao, Yongsheng; Wang, Xu; Tang, Bo

    2017-06-13

    Lyso-TPFP presents lysosomal targetability and an acidic pH-activatable response toward formaldehyde. Thus, it exclusively visualizes lysosomal formaldehyde and is immune against it in neutral cytosol and other organelles. In addition, two-photon fluorescence imaging endows Lyso-TPFP with the capability of in situ tracking formaldehyde in live cells and animals.

  14. Ethanol-Glycerin Fixation with Thymol Conservation: A Potential Alternative to Formaldehyde and Phenol Embalming

    Science.gov (United States)

    Hammer, Niels; Loffler, Sabine; Feja, Christine; Sandrock, Mara; Schmidt, Wolfgang; Bechmann, Ingo; Steinke, Hanno

    2012-01-01

    Anatomical fixation and conservation are required to prevent specimens from undergoing autolysis and decomposition. While fixation is the primary arrest of the structures responsible for autolysis and decomposition, conservation preserves the state of fixation. Although commonly used, formaldehyde has been classified as carcinogenic to humans. For…

  15. [Features of dyslipidemia development and insulin resistance in female workers engaged in methanol and formaldehyde production].

    Science.gov (United States)

    Taranenko, L A

    2013-01-01

    The article covers data on analyzing occupational risk of carbohydrate and lipid metabolism in female workers exosed to methanol and formaldehyde. Findings are that increased contents of the studied chemicals in the air of workplace cause more probable dyslipidemia, insuline resistence in peri-menopausal female workers, these disorders have reliable correlation with occupation.

  16. Estimating the spread rate of urea formaldehyde adhesive on birch (Betula pendula Roth) veneer using fluorescence

    Science.gov (United States)

    Toni Antikainen; Anti Rohumaa; Christopher G. Hunt; Mari Levirinne; Mark Hughes

    2015-01-01

    In plywood production, human operators find it difficult to precisely monitor the spread rate of adhesive in real-time. In this study, macroscopic fluorescence was used to estimate spread rate (SR) of urea formaldehyde adhesive on birch (Betula pendula Roth) veneer. This method could be an option when developing automated real-time SR measurement for...

  17. Pd-Cu/poly(o-Anisidine) nanocomposite as an efficient catalyst for formaldehyde oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Sayed Reza, E-mail: r.hosseini@umz.ac.ir [Nanochemistry Research Laboratory, Faculty of Chemistry, University of Mazandaran, 47416-95447 Babolsar (Iran, Islamic Republic of); Raoof, Jahan-Bakhsh [Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, 47416-95447 Babolsar (Iran, Islamic Republic of); Ghasemi, Shahram; Gholami, Zahra [Nanochemistry Research Laboratory, Faculty of Chemistry, University of Mazandaran, 47416-95447 Babolsar (Iran, Islamic Republic of)

    2016-08-15

    Highlights: • o-Anisidine monomer was electro-polymerized at the pCPE surface in acid medium. • Palladium/copper NPs were prepared by galvanic replacement method at the POA/pCPE. • Pd-Cu NPs showed excellent electrocatalytic activity towards formaldehyde oxidation. • The bimetallic Pd-Cu NPs/POA nanocomposite showed satisfactory long-term stability. - Abstract: In this work, for the first time, the electrocatalytic oxidation of formaldehyde in 0.5 M sulfuric acid solution at spherical bimetallic palladium-copper nanoparticles (Pd-Cu NPs) deposited on the poly (o-Anisidine) film modified electrochemically pretreated carbon paste electrode (POA/pCPE) has been investigated. Highly porous POA film prepared by electropolymerization onto the pCPE was used as a potent support for deposition of the Pd-Cu NPs. The Pd-Cu NPs were prepared through spontaneous and irreversible reaction via galvanic replacement between Pd{sup II} ions and the Cu{sup 0} particles. The prepared Pd-Cu NPs were characterized by scanning electron microscopy, energy dispersive spectroscopy and electrochemical methods. The obtained results showed that the utilization of Cu nanoparticles and pretreatment technique enhances the electrocatalytic activity of the modified electrode towards formaldehyde oxidation. The influence of several parameters on formaldehyde oxidation as well as stability of the Pd-Cu/POA/pCPE has been investigated.

  18. Assimilation of formaldehyde and other C1-compounds by Gliocladium deliquescens and Paecilomyces varioti

    International Nuclear Information System (INIS)

    Sakaguchi, Kenji; Kurane, Ryuichiro; Murata, Machiko

    1975-01-01

    Two fungi were isolated from soil which grew on 0.1--0.2% formaldehyde as the sole carbon source, and identified as Gliocladium deliquescens and Paecilomyces varioti. Both the strains could grow on 5% methanol and 5% Na-formate, while the former could grow even on 7% methanol. Metabolic pathways were traced through two dimensional paper chromatography and autoradiographic techniques using 14 C-formaldehyde, 14 C-methanol or 14 C-CO 2 as substrates. The intracellular metabolites were persued and their quantitative variation with time was measured. Along with the fact that serine and malate appeared in the earlier time, then appeared organic acids and amino acids belonging to TCA cycle, and the fact that hydroxy-pyruvate reductase and phosphoenolpyruvate carboxylase activities were much stronger in methanol culture than in ethanol culture, it was concluded that the two fungi followed the serine pathway in assimilating C 1 -compounds. Oxidation enzymes of methanol and formaldehyde were also studied, and an oxidizing system was found besides usual NAD linked methanol or formaldehyde dehydrogenases. (auth.)

  19. Toxicity of formaldehyde and acrolein mixtures : in vitro studies using nasal epithelial cells

    NARCIS (Netherlands)

    Cassee, F.R.; Stenhuis, W.S.; Groten, J.P.; Feron, V.J.

    1996-01-01

    In vitro studies with human and rat nasal epithelial cells were carried out to investigate the combined toxicity of formaldehyde and acrolein and the role of aldehyde dehydrogenases in this process. These studies showed that the toxic effect of mixtures of aldehydes was additive. In addition,

  20. Sensory irritation to mixtures of formaldehyde, acrolein, and acetaldehyde in rats

    NARCIS (Netherlands)

    Cassee, F.R.; Arts, J.H.E.; Groten, J.P.; Feron, V.J.

    1996-01-01

    Sensory irritation of formaldehyde (FRM), acrolein (ACR) and acetaldehyde (ACE) as measured by the decrease in breathing frequency (DBF) was studied in male Wistar rats using nose-only exposure. Groups of four rats were exposed to each of the single compounds separately or to mixtures of FRM, ACR

  1. Preparation and characterization of poly (urea-formaldehyde) walled dicyclopentadiene microcapsules

    NARCIS (Netherlands)

    Xiong, W.; Zhu, G.; Tang, J.; Dong, B.; Han, N.; Xing, F.; Schlangen, H.E.J.G.

    2013-01-01

    Poly (urea-formaldehyde) (PUF) shelled dicyclopentadiene (DCPD) microcapsules were prepared by in-situ polymerization technology for self-healing concrete applications. It’s found, during the process, sodium dodecyl benzene sulfonate (SDBS) behaves better in emulsification of DCPD than other

  2. Nine years of global hydrocarbon emissions based on source inversion of OMI formaldehyde observations

    NARCIS (Netherlands)

    Bauwens, Maite; Stavrakou, Trissevgeni; Müller, Jean François; De Smedt, Isabelle; Van Roozendael, Michel; Van Der Werf, Guido R.; Wiedinmyer, Christine; Kaiser, Johannes W.; Sindelarova, Katerina; Guenther, Alex

    2016-01-01

    As formaldehyde (HCHO) is a high-yield product in the oxidation of most volatile organic compounds (VOCs) emitted by fires, vegetation, and anthropogenic activities, satellite observations of HCHO are well-suited to inform us on the spatial and temporal variability of the underlying VOC sources. The

  3. Impact of curing time on ageing and degradation of phenol-urea-formaldehyde binder

    DEFF Research Database (Denmark)

    Okhrimenko, D. V.; Thomsen, A. B.; Ceccato, M.

    2018-01-01

    Phenol-urea-formaldehyde (PUF) resin is one of the most important thermosetting polymers. It is widely used in many industrial and construction applications as an organic coating and adhesive. For example, in production of mineral wool for insulation, PUF is used together with the coupling agent (3...

  4. Study of changes in bacterial and viral abundance in formaldehyde - Fixed water samples by epifluorescence microscopy

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Radhakrishnan, S.; Sajila, M.P.; Jacob, B.

    of bacteria and viruses in water samples from Cochin Backwater was determined by SYBR Green I staining and epifluorescence microscopy. The counts were determined for 45 days in samples fixed with 1–6% formaldehyde. The results suggest rapid decline in counts...

  5. Biofiltration of waste gases containing a mixture of formaldehyde and methanol

    Energy Technology Data Exchange (ETDEWEB)

    Prado, O.J.; Veiga, M.C.; Kennes, C. [Chemical Engineering Lab., Faculty of Sciences, Univ. of La Coruna, La Coruna (Spain)

    2004-07-01

    Several biofilters and biotrickling filters were used for the treatment of a mixture of formaldehyde and methanol; and their efficiencies were compared. Results obtained with three different inert filter bed materials (lava rock, perlite, activated carbon) suggested that the packing material had only little influence on the performance. The best results were obtained in a biotrickling filter packed with lava rock and fed a nutrient solution that was renewed weekly. A maximum formaldehyde elimination capacity of 180 g m{sup -3} h{sup -1} was reached, while the methanol elimination capacity rose occasionally to more than 600 g m{sup -3} h{sup -1}. Formaldehyde degradation was affected by the inlet methanol concentration. Several combinations of load vs empty bed residence time (EBRTs of 71.9, 46.5, 30.0, 20.7 s) were studied, reaching a formaldehyde elimination capacity of 112 g m{sup -3} h{sup -1} with about 80% removal efficiency at the lowest EBRT (20.7 s). (orig.)

  6. 75 FR 17163 - Formaldehyde Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2010-04-05

    ... (29 CFR 1910.1048). The standard protects workers from the adverse health effects from occupational... protects workers from the adverse health effects from occupational exposure to formaldehyde, including an... DEPARTMENT OF LABOR Occupational Safety and Health Administration [Docket No. OSHA-2009-0041...

  7. Differential scanning calorimetry of the effects of temperature and humidity on phenol-formaldehyde resin cure

    Science.gov (United States)

    X.-M. Wang; B. Riedl; A.W. Christiansen; R.L. Geimer

    1994-01-01

    Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31...

  8. Phenol-formaldehyde reactivity with lignin in the wood cell wall

    Science.gov (United States)

    Daniel J. Yelle; John Ralph

    2016-01-01

    Latewood from Pinus taeda was reacted with alkaline phenol–formaldehyde (PF) adhesive and characterised using two-dimensional 1H–13C solution-state nuclear magnetic resonance (NMR) spectroscopy so that chemical modification of the wood cell wall polymers, after PF resol curing, could be elucidated. The...

  9. An outbreak of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener

    NARCIS (Netherlands)

    de Wit, F. S.; de Groot, A. C.; Weyland, J. W.; Bos, J. D.

    1988-01-01

    8 cases of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener are presented. Most patients had used nail lacquers containing this resin for many years without trouble, but became sensitized to the resin shortly after the introduction of this particular nail hardener. A

  10. Chromatographic analysis of the reaction of soy flour with formaldehyde and phenol for wood adhesives

    Science.gov (United States)

    Linda F. Lorenz; Charles R. Frihart; James M. Wescott

    2007-01-01

    The desire to make more biobased and lower-cost bonded wood products has led to an interest in replacing some phenol and formaldehyde in wood adhesives with soybean flour. Improved knowledge of the soy protein properties is needed to relate resin chemistry to resin performance before and after wood bonding. To expose the soy protein’s functional groups, it...

  11. In situ ruminal degradation of phytic acid in formaldehyde treated rice bran

    NARCIS (Netherlands)

    Martin-Tereso, J.; Gonzalez, A.; Laar, van H.; Burbara, C.; Pedrosa, M.; Mulder, K.; Hartog, den L.A.; Verstegen, M.W.A.

    2009-01-01

    Rice bran has a very high content of phytic acid (IP6), which is a nutritional antagonist of Ca. Microbial phytase degrades IP6, but ruminal degradation of nutrients can be reduced by formaldehyde treatment. Milk fever in dairy cows can be prevented by reducing available dietary Ca to stimulate Ca

  12. Effects of creatine supplementation along with resistance training on urinary formaldehyde and serum enzymes in wrestlers.

    Science.gov (United States)

    Nasseri, Azadeh; Jafari, Afshar

    2016-04-01

    Formaldehyde is a cytotoxic agent produced from creatine through a metabolic pathway, and in this regard, it has been claimed that creatine supplementation could be cytotoxic. Even though the cytotoxic effects of creatine supplementation have been widely studied, yet little is known about how resistance training can alter these toxic effects. This study aimed to determine the effects of short-term creatine supplementation plus resistance training on the level of urinary formaldehyde and concentrations of serum enzymes in young male wrestlers. In a double-blind design twenty-one subjects were randomized into creatine supplementation (Cr), creatine supplementation plus resistance training (Cr + T) and placebo plus resistance training (Pl + T) groups. Participants ingested creatine (0.3 g/kg/day) or placebo for 7 days. The training protocol consisted of 3 sessions in one week, each session including three sets of 6-9 repetitions at 80-85% of one-repetition maximum for whole-body exercise. Urine and blood samples were collected at baseline and at the end of the supplementation. Creatine supplementation significantly increased the excretion rate of urinary formaldehyde in the Cr and Cr + T groups by 63.4% and 30.4%, respectively (P0.05). These findings indicate that resistance training may lower the increase of urinary formaldehyde excretion induced by creatine supplementation, suggesting that creatine consumption could be relatively less toxic when combined with resistance training.

  13. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  14. Photoinduced catalytic synthesis of biologically important metabolites from formaldehyde and ammonia under plausible "prebiotic" conditions

    Science.gov (United States)

    Delidovich, I. V.; Taran, O. P.; Simonov, A. N.; Matvienko, L. G.; Parmon, V. N.

    2011-08-01

    The article analyzes new and previously reported data on several catalytic and photochemical processes yielding biologically important molecules. UV-irradiation of formaldehyde aqueous solution yields acetaldehyde, glyoxal, glycolaldehyde and glyceraldehyde, which can serve as precursors of more complex biochemically relevant compounds. Photolysis of aqueous solution of acetaldehyde and ammonium nitrate results in formation of alanine and pyruvic acid. Dehydration of glyceraldehyde catalyzed by zeolite HZSM-5-17 yields pyruvaldehyde. Monosaccharides are formed in the course of the phosphate-catalyzed aldol condensation reactions of glycolaldehyde, glyceraldehyde and formaldehyde. The possibility of the direct synthesis of tetroses, keto- and aldo-pentoses from pure formaldehyde due to the combination of the photochemical production of glycolahyde and phosphate-catalyzed carbohydrate chain growth is demonstrated. Erythrulose and 3-pentulose are the main products of such combined synthesis with selectivity up to 10%. Biologically relevant aldotetroses, aldo- and ketopentoses are more resistant to the photochemical destruction owing to the stabilization in hemiacetal cyclic forms. They are formed as products of isomerization of erythrulose and 3-pentulose. The conjugation of the concerned reactions results in a plausible route to the formation of sugars, amino and organic acids from formaldehyde and ammonia under presumed 'prebiotic' conditions.

  15. CONTINUOUS FORMALDEHYDE MEASUREMENT SYSTEM BASED ON MODIFIED FOURIER TRANSFORM INFRARED SPECTROSCOPY

    Science.gov (United States)

    EPA is developing advanced open-path and cell-based optical techniques for time-resolved measurement of priority hazardous air pollutants such as formaldehyde (HCHO). Due to its high National Air Toxics Assessment risk factor, there is increasing interest in continuous measuremen...

  16. Evaluation on potential for assessing indoor formaldehyde using biosensor system based on swimming behavior of Japanese medaka (oryzias latipes)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jonghun [Department of Architecture, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo, 153-8505 (Japan); Kato, Shinsuke; Tatsuma, Tetsu [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo, 153-8505 (Japan); Takeuchi, Kenichiro [Sumitomo Forestry Co., Ltd. (Japan); Kang, Ik Joon [Aquatic Biomonitoring and Environmental Laboratory, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581 (Japan)

    2011-04-15

    In order to develop an early-warning biosensor system for predicting the impact on health of long-term and low-level exposure to indoor chemical compounds, e.g. volatile organic compounds (VOCs), we evaluated the potential for assessing indoor air quality using the biosensor system based on the swimming behavior of Japanese medaka (oryzias latipes) as an indicator of indoor air quality in the beginning. As a technology to dissolve chemical compounds into water efficiently, a micro bubble generator was introduced. The test chemical was formaldehyde which is a representative of chemical compounds existing indoors. The result of the measuring solubility of formaldehyde was that formaldehyde concentration in water was raised to 0.12 mg/L when 1.0 mg/m{sup 3} of formaldehyde in air was bubbled for approximately 44 h. The correlation between the 0.1 mg/L of formaldehyde in water, which is roughly equivalent to 0.83 mg/m{sup 3} of formaldehyde in air, and the swimming activities of medaka was investigated. The fish showed abnormal behavior compared to one under a control treatment, e.g. the body movement distance decreased and the duration time near the upper water column increased significantly. It was verified that it is possible to detect concentrations of formaldehyde of 0.83 mg/m{sup 3} in indoor air using this proposed biosensor system. (author)

  17. Detection of Waterborne and Airborne Formaldehyde: From Amperometric Chemosensing to a Visual Biosensor Based on Alcohol Oxidase

    Directory of Open Access Journals (Sweden)

    Sasi Sigawi

    2014-02-01

    Full Text Available A laboratory prototype of a microcomputer-based analyzer was developed for quantitative determination of formaldehyde in liquid samples, based on catalytic chemosensing elements. It was shown that selectivity for the target analyte could be increased by modulating the working electrode potential. Analytical parameters of three variants of the amperometric analyzer that differed in the chemical structure/configuration of the working electrode were studied. The constructed analyzer was tested on wastewater solutions that contained formaldehyde. A simple low-cost biosensor was developed for semi-quantitative detection of airborne formaldehyde in concentrations exceeding the threshold level. This biosensor is based on a change in the color of a solution that contains a mixture of alcohol oxidase from the yeast Hansenula polymorpha, horseradish peroxidase and a chromogen, following exposure to airborne formaldehyde. The solution is enclosed within a membrane device, which is permeable to formaldehyde vapors. The most efficient and sensitive biosensor for detecting formaldehyde was the one that contained alcohol oxidase with an activity of 1.2 U·mL−1. The biosensor requires no special instrumentation and enables rapid visual detection of airborne formaldehyde at concentrations, which are hazardous to human health.

  18. Adsorption and photocatalytic oxidation of formaldehyde on a clay-TiO{sub 2} composite

    Energy Technology Data Exchange (ETDEWEB)

    Kibanova, Daria [Facultad de Quimica, Universidad Nacional Autonoma de Mexico (Mexico); Departamento de Procesos y Tecnologia, Universidad Autonoma Metropolitana (Mexico); Sleiman, Mohamad [Lawrence Berkeley National Laboratory, Indoor Environment Group, Environmental Energy Technologies Division (United States); Cervini-Silva, Javiera, E-mail: jcervini@correo.cua.uam.mx [Departamento de Procesos y Tecnologia, Universidad Autonoma Metropolitana (Mexico); NASA Astrobiology Institute (United States); Destaillats, Hugo, E-mail: HDestaillats@lbl.gov [Lawrence Berkeley National Laboratory, Indoor Environment Group, Environmental Energy Technologies Division (United States); Arizona State University, Department of Chemistry and Biochemistry (United States)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Formaldehyde adsorption and photocatalytic elimination on hectorite-TiO{sub 2} nanocomposites. Black-Right-Pointing-Pointer Dark adsorption in dry air >4 times higher than P25 (reference). Black-Right-Pointing-Pointer Dark adsorption in humid air dominated by adsorbed water layer. Black-Right-Pointing-Pointer Photocatalytic removal efficiency proportional to the Ti content, increased with contact time. Black-Right-Pointing-Pointer More complete elimination with 254 + 185 nm irradiation. - Abstract: We investigated the adsorption capacity and photocatalytic removal efficiency of formaldehyde using a hectorite-TiO{sub 2} composite in a bench flow reactor. The same experimental conditions were applied to pure TiO{sub 2} (Degussa P25) as a reference. The catalysts were irradiated with either a UVA lamp (365 nm) or with one of two UVC lamps of 254 nm and 254 + 185 nm, respectively. Formaldehyde was introduced upstream at concentrations of 100-500 ppb, with relative humidity (RH) in the range 0-66% and residence times between 50 and 500 ms. Under dry air and without illumination, saturation of catalyst surfaces was achieved after {approx}200 min for P25 and {approx}1000 min for hectorite-TiO{sub 2}. The formaldehyde uptake capacity by hectorite-TiO{sub 2} was 4.1 times higher than that of P25, almost twice the BET surface area ratio. In the presence of humidity, the difference in uptake efficiency between both materials disappeared, and saturation was achieved faster (after {approx}200 min at 10% RH and {approx}60 min at 65% RH). Under irradiation with each of the three UV sources, removal efficiencies were proportional to the Ti content and increased with contact time. The removal efficiency decreased at high RH. A more complete elimination of formaldehyde was observed with the 254 + 185 nm UV source.

  19. Observations of glyoxal and formaldehyde as metrics for the anthropogenic impact on rural photochemistry

    Directory of Open Access Journals (Sweden)

    J. P. DiGangi

    2012-10-01

    Full Text Available We present simultaneous fast, in-situ measurements of formaldehyde and glyoxal from two rural campaigns, BEARPEX 2009 and BEACHON-ROCS, both located in Pinus Ponderosa forests with emissions dominated by biogenic volatile organic compounds (VOCs. Despite considerable variability in the formaldehyde and glyoxal concentrations, the ratio of glyoxal to formaldehyde, RGF, displayed a very regular diurnal cycle over nearly 2 weeks of measurements. The only deviations in RGF were toward higher values and were the result of a biomass burning event during BEARPEX 2009 and very fresh anthropogenic influence during BEACHON-ROCS. Other rapid changes in glyoxal and formaldehyde concentrations have hardly any affect on RGF and could reflect transitions between low and high NO regimes. The trend of increased RGF from both anthropogenic reactive VOC mixtures and biomass burning compared to biogenic reactive VOC mixtures is robust due to the short timescales over which the observed changes in RGF occurred. Satellite retrievals, which suggest higher RGF for biogenic areas, are in contrast to our observed trends. It remains important to address this discrepancy, especially in view of the importance of satellite retrievals and in situ measurements for model comparison. In addition, we propose that RGF represents a useful metric for biogenic or anthropogenic reactive VOC mixtures and, in combination with absolute concentrations of glyoxal and formaldehyde, furthermore represents a useful metric for the extent of anthropogenic influence on overall reactive VOC processing via NOx. In particular, RGF yields information about not simply the VOCs dominating reactivity in an airmass, but the VOC processing itself that is directly coupled to ozone and secondary organic aerosol production.

  20. CCQM-K90, formaldehyde in nitrogen, 2 μmol mol-1 Final report

    Science.gov (United States)

    Viallon, Joële; Flores, Edgar; Idrees, Faraz; Moussay, Philippe; Wielgosz, Robert Ian; Kim, D.; Kim, Y. D.; Lee, S.; Persijn, S.; Konopelko, L. A.; Kustikov, Y. A.; Malginov, A. V.; Chubchenko, I. K.; Klimov, A. Y.; Efremova, O. V.; Zhou, Z.; Possolo, A.; Shimosaka, T.; Brewer, P.; Macé, T.; Ferracci, Valerio; Brown, Richard J. C.; Aoki, Nobuyuki

    2017-01-01

    The CCQM-K90 comparison is designed to evaluate the level of comparability of national metrology institutes (NMI) or designated institutes (DI) measurement capabilities for formaldehyde in nitrogen at a nominal mole fraction of 2 μmol mol-1. The comparison was organised by the BIPM using a suite of gas mixtures prepared by a producer of specialty calibration gases. The BIPM assigned the formaldehyde mole fraction in the mixtures by comparison with primary mixtures generated dynamically by permeation coupled with continuous weighing in a magnetic suspension balance. The BIPM developed two dynamic sources of formaldehyde in nitrogen that provide two independent values of the formaldehyde mole fraction: the first one based on diffusion of trioxane followed by thermal conversion to formaldehyde, the second one based on permeation of formaldehyde from paraformaldehyde contained in a permeation tube. Two independent analytical methods, based on cavity ring down spectroscopy (CRDS) and Fourier transform infrared spectroscopy (FTIR) were used for the assignment procedure. Each participating institute was provided with one transfer standard and value assigned the formaldehyde mole fraction in the standard based on its own measurement capabilities. The stability of the formaldehyde mole fraction in transfer standards was deduced from repeated measurements performed at the BIPM before and after measurements performed at participating institutes. In addition, 5 control standards were kept at the BIPM for regular measurements during the course of the comparison. Temporal trends that approximately describe the linear decrease of the amount-of-substance fraction of formaldehyde in nitrogen in the transfer standards over time were estimated by two different mathematical treatments, the outcomes of which were proposed to participants. The two treatments also differed in the way measurement uncertainties arising from measurements performed at the BIPM were propagated to the

  1. Growth of Candida boidinii on methanol and the activity of methanol-degrading enzymes as affected from formaldehyde and methylformate.

    Science.gov (United States)

    Aggelis, G; Margariti, N; Kralli, C; Flouri, F

    2000-06-23

    Formaldehyde and methylformate affect the growth of Candida boidinii on methanol and the activity of methanol-degrading enzymes. The presence of both intermediates in the feeding medium caused an increase in biomass yield and productivity and a decrease in the specific rate of methanol consumption. In the presence of formaldehyde, the activity of formaldehyde dehydrogenase and formate dehydrogenase was essentially increased, whereas the activity of methanol oxidase was decreased. On the contrary, the presence of methylformate caused an increase of the activity of methanol oxidase and a decrease of the activity of formaldehyde dehydrogenase and formate dehydrogenase. Interpretations concerning the yeast behavior in the presence of intermediate oxidation products were considered and discussed.

  2. The health- and addictive effectes due to exposure to aldehydes of cigarette smoke. Part 1; Acetaldehyde, Formaldehyde, Acrolein and Propionaldehyde

    NARCIS (Netherlands)

    van Andel I; Schenk E; Rambali B; Wolterink G; van de Werken G; Stevenson H; van Aerts LAGJM; Vleeming W; LEO; LGM; LOC; CRV

    2003-01-01

    In deze literatuurstudie worden de gezondheids- en mogelijke verslavende effecten van blootstelling aan aldehyden ten gevolge van het roken van sigaretten beschreven. Dit literatuuronderzoek richt zich met name op acetaldehyde, formaldehyde, acrolein, en propionaldehyde. Alle aldehyden veroorzaken

  3. Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity (journal)

    Science.gov (United States)

    The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test meth...

  4. Determination of partition and diffusion coefficient of formaldehyde in selected building materials and impact of relative humidity

    Science.gov (United States)

    The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test meth...

  5. OMI/Aura Formaldehyde (HCHO) Total Column Global 0.25deg Lat/Lon Grid V003

    Data.gov (United States)

    National Aeronautics and Space Administration — The Version-3 Aura-OMI Formaldehyde Product OMHCHOG is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omhchog_v003.shtml) from the NASA Goddard Earth Sciences...

  6. Formaldehyde in Alcoholic Beverages: Large Chemical Survey Using Purpald Screening Followed by Chromotropic Acid Spectrophotometry with Multivariate Curve Resolution

    Directory of Open Access Journals (Sweden)

    Julien A. Jendral

    2011-01-01

    Full Text Available A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L. 210 samples (41% gave a positive purpald reaction. In the second step, formaldehyde in positive samples is confirmed by quantitative spectrophotometry of the chromotropic acid-formaldehyde derivative combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS. Calculation of UV-VIS and 13C NMR spectra confirmed the monocationic dibenzoxanthylium structure as the product of the reaction and disproved the widely cited para,para-quinoidal structure. Method validation for the spectrophotometric procedure showed a detection limit of 0.09 mg/L and a precision of 4.2–8.2% CV. In total, 132 samples (26% contained formaldehyde with an average of 0.27 mg/L (range 0–14.4 mg/L. The highest incidence occurred in tequila (83%, Asian spirits (59%, grape marc (54%, and brandy (50%. Our survey showed that only 9 samples (1.8% had formaldehyde levels above the WHO IPCS tolerable concentration of 2.6 mg/L.

  7. Formaldehyde Adsorption into Clinoptilolite Zeolite Modified with the Addition of Rich Materials and Desorption Performance Using Microwave Heating

    Directory of Open Access Journals (Sweden)

    Amin Kalantarifard

    2016-01-01

    Full Text Available Granite, bentonite, and starch were mixed with clinoptilolite zeolite to produce a modified zeolite. The modified zeolite was tested for its ability to absorb formaldehyde from air. The modified sample formaldehyde adsorption capacity was then compared with those of commercially available clinoptilolite, faujasite (Y, mordenite, and zeolite type A. Studies were focused on the relationships between the physical characteristics of the selected zeolites (crystal structure, surface porosity, pore volume, pore size and their formaldehyde adsorption capacity. The removal of starch at high temperature (1100°C and addition of bentonite during modified clinoptilolite zeolite (M-CLZ preparation generated large pores and a higher pore distribution on the sample surface, which resulted in higher adsorption capacity. The formaldehyde adsorption capacities of M-CLZ, clinoptilolite, faujasite (Y, zeolite type A, and mordenite were determined to be 300.5, 194.5, 123.7, 106.7, and 70 mg per gram of zeolite, respectively. The M-CLZ, clinoptilolite, and faujasite (Y crystals contained both mesoporous and microporous structures, which resulted in greater adsorption, while the zeolite type A crystal showed a layered structure and lower surface porosity, which was less advantageous for formaldehyde adsorption. Furthermore, zeolite regeneration using microwave heating was investigated focusing on formaldehyde removal by desorption from the zeolite samples. XRD, XRF, N2 adsorption/desorption, and FE-SEM experiments were performed to characterize the surface structure and textural properties the zeolites selected in this study.

  8. Formaldehyde and acetaldehyde exposure mitigation in US residences: In-home measurements of ventilation control and source control

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Phillip N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hotchi, Toshifumi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Russell, Marion L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-10-01

    Measurements were taken in new US residences to assess the extent to which ventilation and source control can mitigate formaldehyde exposure. Increasing ventilation consistently lowered indoor formaldehyde concentrations. However, at a reference air exchange rate of 0.35 h-1, increasing ventilation was up to 60% less effective than would be predicted if the emission rate were constant. This is consistent with formaldehyde emission rates decreasing as air concentrations increase, as observed in chamber studies. In contrast, measurements suggest acetaldehyde emission was independent of ventilation rate. To evaluate the effectiveness of source control, formaldehyde concentrations were measured in Leadership in Energy and Environmental Design (LEED) certified/Indoor airPLUS homes constructed with materials certified to have low emission rates of volatile organic compounds (VOC). At a reference air exchange rate of 0.35 h-1, and adjusting for home age, temperature and relative humidity, formaldehyde concentrations in homes built with low-VOC materials were 42% lower on average than in reference new homes with conventional building materials. Without adjustment, concentrations were 27% lower in the low-VOC homes. The mean and standard deviation of formaldehyde concentration were 33 μg m-3 and 22 μg m-3 for low-VOC homes and 45 μg m-3 and 30 μg m-3 for conventional.

  9. Formaldehyde in alcoholic beverages: large chemical survey using purpald screening followed by chromotropic Acid spectrophotometry with multivariate curve resolution.

    Science.gov (United States)

    Jendral, Julien A; Monakhova, Yulia B; Lachenmeier, Dirk W

    2011-01-01

    A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L). 210 samples (41%) gave a positive purpald reaction. In the second step, formaldehyde in positive samples is confirmed by quantitative spectrophotometry of the chromotropic acid-formaldehyde derivative combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS). Calculation of UV-VIS and (13)C NMR spectra confirmed the monocationic dibenzoxanthylium structure as the product of the reaction and disproved the widely cited para,para-quinoidal structure. Method validation for the spectrophotometric procedure showed a detection limit of 0.09 mg/L and a precision of 4.2-8.2% CV. In total, 132 samples (26%) contained formaldehyde with an average of 0.27 mg/L (range 0-14.4 mg/L). The highest incidence occurred in tequila (83%), Asian spirits (59%), grape marc (54%), and brandy (50%). Our survey showed that only 9 samples (1.8%) had formaldehyde levels above the WHO IPCS tolerable concentration of 2.6 mg/L.

  10. Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia

    Science.gov (United States)

    Weber, Arthur L.

    1998-01-01

    Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.

  11. Fabrication and optimisation of optical biosensor using alcohol oxidase enzyme to evaluate detection of formaldehyde

    Science.gov (United States)

    Rachim, A.; Sari, A. P.; Nurlely, Fauzia, V.

    2017-07-01

    In this study, a new and simple biosensor base on alcohol oxidase (AOX)-enzyme for detecting formaldehyde in aqueous solutions has been successfully fabricated. The alcohol oxidase (AOX) enzyme was immobilized on poly-n-butyl acrylic-co-N-acryloxysuccinimide (nBA-NAS) membrane containing chromoionophore. The chemical reaction between AOX and formaldehyde generates a colour change of chromoionophore detected by optical absorbance measured in UV Vis. This paper focuses on the concentration optimization of buffer phosphate solution, response time, the quantity of enzyme and the measurement of the detection range of biosensors. The result shows that the optimum concentration and pH of buffer phosphate solution is 0.05 M and pH 7, respectively. The optimum response time is 3 min, the optimum unit of enzyme for biosensor is 1 unit/sample and the detection range of biosensor is 0.264 mM with R2 = 0.9421.

  12. Monitoring the efficacy of steam and formaldehyde treatment of naturally Salmonella-infected layer houses

    DEFF Research Database (Denmark)

    Gradel, K.O.; Jørgensen, J.C.; Andersen, J.S.

    2004-01-01

    steam treated in a download period, aiming at greater than or equal to60degreesC and 100% relative humidity (RH) during a 24-h period, with or without the addition of 30 ppm formaldehyde. In addition, two control layer houses were disinfected chemically. Salmonella samples taken from predetermined sites...... before and after treatment were tested qualitatively for Salmonella and coliforms. Samples with indicator bacteria (feed inoculated with Escherichia coli or Enterococcus faecalis and faeces with naturally occurring E. coli and enterococci) were placed during steam-treatment at 12 sites in each house...... (where the temperature was logged at 5-min intervals) and tested for surviving bacteria. Generally, the field test results confirmed the results of laboratory tests, especially when 30 ppm formaldehyde was added to the steam. In well-sealed houses, the recommended temperature-humidity-time scheme...

  13. Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents

    Science.gov (United States)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, the current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is nonregenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture.

  14. The effect of α-cellulose fiber on the properties of melamine-formaldehyde molding compounds

    International Nuclear Information System (INIS)

    Khatibi, M. A.; Beheshti, M. A.; Morshedian, J.

    2001-01-01

    Melamine-formaldehyde molding compounds have found different industrial applications. This is due to their good mechanical properties such as hardness, gloss and high modulus and strength. One of the major components of these compounds is α-cellulose fiber and has a major effect on the mechanical properties. Although this fiber is being used in these compounds for a long time, there is not much data available of α-cellulose fibers on the physical and mechanical properties of melamine-formaldehyde molding compounds being investigated. Results show that although the microstructures of these two fibers are quite different from each other, but they do not have any effect on the mechanical properties of the molding. Whereas, it has a significant effect on the wettability (processing condition) and glossiness of the mol dings. Since this latter property is very important in house wares applications, the darker mol dings can not be used in domestic applications

  15. A novel reaction catalysed by active carbons production of dichloromethane from phosgene and formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, T A; Stacey, M H

    1984-08-01

    A variety of Activated charcoals have been found to catalyse a reaction between phosgene and formaldehyde. In a continuous flow fluidized bed reactor, the reaction rate reaches a broad maximum near 170/sup 0/C where the selectivity is consistent with the stoichiometry. The reaction proceeds via a strongly adsorbed intermediate which has been identified as chloromethyl chloroformate. This ester is an adduct of formaldehyde and phosgen and forms rapidly above 100/sup 0/C in co-adsorption/desorption experiments. It decomposes rapidly 170/sup 0/C without significant desorption of the intact molecule to give the observed products dichloromethane and carbon dioxide. Under steady-state conditions the rate-determining step is the formation of this ester so that it is normally only present on the surface at low coverages; hence it is not observable in the gas phase. The catalysis is probably due to the presence of polar acid or base sites on the surface of the activated charcoals.

  16. Synergic effect of. gamma. irradiation and formaldehyde on growth of barley seedlings after caryopse treatment

    Energy Technology Data Exchange (ETDEWEB)

    Silvy, A; Maltet, P; Jonard, R [CEA Centre d' Etudes Nucleaires de Cadarache, 13 - Saint-Paul-les-Durance (France). Service de Radio-Agronomie; Montpellier-1 Univ., 34 (France))

    1980-06-30

    A synergic effect is observed on the shortening of first leaf of seedlings following combined treatments with ..gamma.. irradiation before or during exposure to formaldehyde in gaseous phase on barley caryopses with low water content (4,7%) under anoxic conditions. This effect being attributed to the great reactivity of free radicals in such dry and anoxic systems, new methods of mutagenic treatment can therefore be envisaged for higher plants.

  17. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the COFFEE Instrument

    Science.gov (United States)

    Marrero, Josette; St. Clair, Jason; Yates, Emma; Swanson, Andrew; Gore, Warren; Iraci, Laura; Hanisco, Thomas

    2016-04-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. We will present results from flights performed over the Central Valley of California, including boundary layer measurements and vertical profiles in the tropospheric column. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. These results will be presented in conjunction with formaldehyde. Targets in the Central Valley consist of an oil field, agricultural areas, and highways, each of which can emit HCHO primarily and generate HCHO through secondary production. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  18. Synergic effect of γ irradiation and formaldehyde on growth of barley seedlings after caryopse treatment

    International Nuclear Information System (INIS)

    Silvy, Andre; Maltet, Patrick; Jonard, Robert

    1980-01-01

    A synergic effect is observed on the shortening of first leaf of seedlings following combined treatments with γ irradiation before or during exposure to formaldehyde in gaseous phase on barley caryopses with low water content (4,7%) under anoxic conditions. This effect being attributed to the great reactivity of free radicals in such dry and anoxic systems, new methods of mutagenic treatment can therefore be envisaged for higher plants [fr

  19. A Reagentless Amperometric Formaldehyde-Selective Chemosensor Based on Platinized Gold Electrodes

    OpenAIRE

    Demkiv, Olha; Smutok, Oleh; Gonchar, Mykhailo; Nisnevitch, Marina

    2017-01-01

    Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in th...

  20. Fixing of various simulated radioactive wastes in urea-formaldehyde resin

    International Nuclear Information System (INIS)

    Du Dahai; Wei Peng

    1986-01-01

    This paper outlines the results of the fixing of a variety of simulated radioactive wastes in the urea-formaldehyde resin. The radioactive waste materials fixed include spent ion exchange resin, concentrates of NaNO 3 -NaBO 2 as well as NaBO 2 and sludge. The performance of the fixed products has been improved by means of selecting the synthetic conditions of resin, a suitable hardener and an inorganic additive

  1. Indoor Levels of Formaldehyde and Other Pollutants and Relationship to Air Exchange Rates and Human Activities

    Science.gov (United States)

    Huangfu, Y.; O'Keeffe, P.; Kirk, M.; Walden, V. P.; Lamb, B. K.; Jobson, B. T.

    2017-12-01

    This paper reports results on an indoor air quality study conducted on six homes in summer and winter, contrasting indoor and outdoor concentrations of O3, CO, CO2, NOx, PM2.5, and selected volatile organic hydrocarbons measured by PTR-MS. Data were collected as 1 minute averages. Air exchange rates of the homes were determined by CO2 tracer release. Smart home sensors, recording human activity level in various places in the home, and window and doors openings, were utilized to better understand the link between human activity and indoor air pollution. From our study, averaged air exchange rates of the homes ranged from 0.2 to 1.2 hour-1 and were greatly affected by the ventilation system type and window and door openings. In general, a negative correlation between air exchange rate and indoor VOCs levels was observed, with large variation of pollutant levels between the homes. For most of the VOCs measured in the house, including formaldehyde and acetaldehyde, summer levels were much higher than winter levels. In some homes formaldehyde levels displayed a time of day variation that was linked to changes in indoor temperature. During a wildfire period in the summer of 2015, outdoor levels of PM2.5, formaldehyde, and benzene dramatically increased, significantly impacting indoor levels due to infiltration. Human activities, such as cooking, can significantly change the levels of most of the compounds measured in the house and the levels can be significantly elevated for short periods of time, with peak levels can be several orders higher compared with typical levels. The data suggest that an outcome of state energy codes that require new homes to be energy efficient, and as a consequence built with lower air exchange rates, will be unacceptable levels of air toxics, notably formaldehyde.

  2. Lawps ion exchange column gravity drain of spherical resorcinol formaldehyde resin

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Herman, D. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Restivo, M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-28

    Experiments at several different scales were performed to understand the removal of spherical resorcinol formaldehyde (sRF) ion exchange resin using a gravity drain system with a valve located above the resin screen in the ion exchange column (IXC). This is being considered as part of the design for the Low Activity Waste Pretreatment System (LAWPS) to be constructed at the DOE Hanford Site.

  3. Effects of reuse and bleach/formaldehyde reprocessing on polysulfone and polyamide hemodialyzers.

    Science.gov (United States)

    Cornelius, Rena M; McClung, W Glenn; Barre, Paul; Esguerra, Fe; Brash, John L

    2002-01-01

    The surface features, morphology, and blood interactions of fibers from pristine, bleach/formaldehyde reprocessed, and reused Fresenius Polysulfone High Flux (Hemoflow F80B) hemodialyzers and Gambro Polyflux 21S Polyamide hemodialyzers have been studied. SEM images of fibers from both hemodialyzer types revealed a dense skin layer on the inner surface and a relatively thick porous layer on the outer surface. The 21S polyamide support layer consisted of interconnected highly porous structures. Environmental scanning electron microscopy and atomic force microscopy images of both membrane types showed alterations in morphology due to reprocessing and reuse; however the changes were more marked for the 21S polyamide dialyzers. Fluorescence microscopy images showed only minimal fluorescence associated with the fibers after patient use and reprocessing, suggesting that blood derived deposits were removed by processing. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were studied using SDS-PAGE and immunoblotting. Before bleach/formaldehyde treatment, protein layers of considerable amount and complexity were found on the blood side of singly and multiply used dialyzers. Proteins adsorbed on the dialysate side were predominantly in the molecular mass region below 30 kDa. However, some higher molecular mass proteins were detected on the dialysate side of the 21 S polyamide dialyzers. Very little protein was detected on dialyzers that were treated with bleach/formaldehyde after dialysis, regardless of whether they had been used/reprocessed once or 12 times.

  4. Metabolic evaluation of skin absorption of tritiated formaldehyde in hairless rats

    International Nuclear Information System (INIS)

    Trivedi, A.

    1993-11-01

    Tritiated organics are present as trace impurities in tritium handling facilities. Tritiated formaldehyde has been detected in the atmosphere and gaseous effluents of tritium handling and storage sites. The ability of tritiated formaldehyde to diffuse through the skin is a possible route of intake. Since the metabolism of tritium through this mode of contamination is not currently established, experiments were performed in which tritiated formaldehyde was applied topically on the dorsal skin of hairless rats. These experiments demonstrated that tritium was assimilated and retained in the exposed skin as organically bound tritium (OBT). This retained OBT dominates tritium turnover in the body. OBT retention in the unexposed skin, liver, heart and kidneys was also observed. The loss of tritium from the animals showed that about 10% of the applied tritium was excreted in urine. It is assumed that the rest of the applied activity may have been lost through other excretory pathways, or may not have entered into the body. The biokinetics of tritium excretion is best described by a sum of three exponential functions. Most of the excreted tritium was in the form of OBT (90%) and results in the rapid clearing of OBT in the skin to urine and retention in other tissues. The evaluation of the dose-rate data showed that the dose-rate to exposed skin was almost a magnitude greater than the dose-rate to other organs. (author). 21 refs., 4 tabs., 4 figs

  5. An assessment of formaldehyde emissions from laminate flooring manufactured in China.

    Science.gov (United States)

    Pierce, Jennifer S; Abelmann, Anders; Lotter, Jason T; Ruestow, Peter S; Unice, Kenneth M; Beckett, Evan M; Fritz, Heidi A; Bare, Jennifer L; Finley, Brent L

    2016-11-01

    Formaldehyde emissions from two laminate flooring products, labeled as California Air Resources Board (CARB) compliant, were evaluated. Passive 24-hr samples (n = 79) and real-time measurements were collected following installation and removal of the products in two rooms of similar size. Mean formaldehyde concentrations following installation were 0.038 and 0.022 ppm for Products 1 and 2 respectively, and 7 days after flooring removal the concentrations returned to background pre-installation levels. Both products were also evaluated in a small chamber (ASTM D6007) using Deconstructive (de-laminated product) and Non-Deconstructive (intact product) methods. Deconstructive testing showed that Product 1 exceeded the applicable CARB emission standard by 4-fold, while Product 2 was equivalent to the standard. Non-Deconstructive measurements were far below the Deconstructive results and were used to predict 24-hr steady-state room air concentrations. Based on the products that we tested (one of which was found to not be compliant with the CARB standard), the airborne formaldehyde concentrations measured following installation in a real-world setting would not be expected to elicit adverse acute health effects. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Intercomparison of 4 Years of Global Formaldehyde Observations from the GOME-2 and OMI Sensors

    Science.gov (United States)

    De Smedt, Isabelle; Van Roozendael, Michel; Stravrakou, Trissevgeni; Muller, Jean-Francois; Chance, Kelly; Kurosu, Thomas

    2012-11-01

    Formaldehyde (H2CO) tropospheric columns have been retrieved since 2007 from backscattered UV radiance measurements performed by the GOME-2 instrument on the EUMETSAT METOP-A platform. This data set extends the successful time-series of global H2CO observations established with GOME/ ERS-2 (1996-2003), SCIAMACHY/ ENVISAT (2003-2012), and OMI on the NASA AURA platform (2005-now). In this work, we perform an intercomparison of the H2CO tropospheric columns retrieved from GOME-2 and OMI between 2007 and 2010, respectively at BIRA-IASB and at Harvard SAO. We first compare the global formaldehyde data products that are provided by each retrieval group. We then investigate each step of the retrieval procedure: the slant column fitting, the reference sector correction and the air mass factor calculation. New air mass factors are computed for OMI using external parameters consistent with those used for GOME-2. By doing so, the impacts of the different a priori profiles and aerosol corrections are quantified. The remaining differences are evaluated in view of the expected diurnal variations of the formaldehyde concentrations, based on ground-based measurements performed in the Beijing area.

  7. Removal of formaldehyde from gas streams via packed-bed dielectric barrier discharge plasmas

    International Nuclear Information System (INIS)

    Ding Huixian; Zhu Aimin; Yang Xuefeng; Li Cuihong; Xu Yong

    2005-01-01

    Formaldehyde is a major indoor air pollutant and can cause serious health disorders in residents. This work reports the removal of formaldehyde from gas streams via alumina-pellet-filled dielectric barrier discharge plasmas at atmospheric pressure and 70 deg. C. With a feed gas mixture of 140 ppm HCHO, 21.0% O 2 , 1.0% H 2 O in N 2 , ∼92% of formaldehyde can be effectively destructed at GHSV (gas flow volume per hour per discharge volume) of 16 500 h -1 and E in = 108 J l -1 . An increase in the specific surface area of the alumina pellets enhances the HCHO removal, and this indicates that the adsorbed HCHO species may have a lower C-H bond breakage energy. Based on an examination of the influence of gas composition on the removal efficiency, the primary destruction pathways, besides the reactions initiated by discharge-generated radicals, such as O, H, OH and HO 2 , may include the consecutive dissociations of HCHO molecules and HCO radicals through their collisions with vibrationally- and electronically-excited metastable N 2 species. The increase of O 2 content in the inlet gas stream is able to diminish the CO production and to promote the formation of CO 2 via O-atom or HO 2 -radical involved reactions

  8. Micro-Electromechanical Acoustic Resonator Coated with Polyethyleneimine Nanofibers for the Detection of Formaldehyde Vapor

    Directory of Open Access Journals (Sweden)

    Da Chen

    2018-02-01

    Full Text Available We demonstrate a promising strategy to combine the micro-electromechanical film bulk acoustic resonator and the nanostructured sensitive fibers for the detection of low-concentration formaldehyde vapor. The polyethyleneimine nanofibers were directly deposited on the resonator surface by a simple electrospinning method. The film bulk acoustic resonator working at 4.4 GHz acted as a sensitive mass loading platform and the three-dimensional structure of nanofibers provided a large specific surface area for vapor adsorption and diffusion. The ultra-small mass change induced by the absorption of formaldehyde molecules onto the amine groups in polyethyleneimine was detected by measuring the frequency downshift of the film bulk acoustic resonator. The proposed sensor exhibits a fast, reversible and linear response towards formaldehyde vapor with an excellent selectivity. The gas sensitivity and the detection limit were 1.216 kHz/ppb and 37 ppb, respectively. The study offers a great potential for developing sensitive, fast-response and portable sensors for the detection of indoor air pollutions.

  9. Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air

    Science.gov (United States)

    Lui, K. H.; Ho, Steven Sai Hang; Louie, Peter K. K.; Chan, C. S.; Lee, S. C.; Hu, Di; Chan, P. W.; Lee, Jeffrey Chi Wai; Ho, K. F.

    2017-03-01

    Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012-2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).

  10. A Reagentless Amperometric Formaldehyde-Selective Chemosensor Based on Platinized Gold Electrodes.

    Science.gov (United States)

    Demkiv, Olha; Smutok, Oleh; Gonchar, Mykhailo; Nisnevitch, Marina

    2017-05-06

    Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in the chemosensor's selectivity for the target analyte. The sensitivity of the best chemosensor prototype to formaldehyde is uniquely high (28180 A·M -1 ·m -2 ) with a detection limit of 0.05 mM. The chemosensor remained stable over a one-year storage period. The formaldehye-selective chemosensor was tested on samples of commercial preparations. A high correlation was demonstrated between the results obtained by the proposed chemosensor, chemical and enzymatic methods ( R = 0.998). The developed formaldehyde-selective amperometric chemosensor is very promising for use in industry and research, as well as for environmental control.

  11. Low-temperature plasma-catalytic oxidation of formaldehyde in atmospheric pressure gas streams

    International Nuclear Information System (INIS)

    Ding Huixian; Zhu Aimin; Lu Fugong; Xu Yong; Zhang Jing; Yang Xuefeng

    2006-01-01

    Formaldehyde (HCHO) is a typical air pollutant capable of causing serious health disorders in human beings. This work reports plasma-catalytic oxidation of formaldehyde in gas streams via dielectric barrier discharges over Ag/CeO 2 pellets at atmospheric pressure and 70 0 C. With a feed gas mixture of 276 ppm HCHO, 21.0% O 2 , 1.0% H 2 O in N 2 , ∼99% of formaldehyde can be effectively destructed with an 86% oxidative conversion into CO 2 at GHSV of 16500 h -1 and input discharge energy density of 108 J l -1 . At the same experimental conditions, the conversion percentages of HCHO to CO 2 from pure plasma-induced oxidation (discharges over fused silica pellets) and from pure catalytic oxidation over Ag/CeO 2 (without discharges) are 6% and 33% only. The above results and the CO plasma-catalytic oxidation experiments imply that the plasma-generated short-lived gas phase radicals, such as O and HO 2 , play important roles in the catalytic redox circles of Ag/CeO 2 to oxidize HCHO and CO to CO 2

  12. Infrared Line Intensities for Formaldehyde from Simultaneous Measurements in the Infrared and Far Infrared Spectral Ranges

    Science.gov (United States)

    Fissiaux, L.; Földes, T.; Tchana, F. Kwabia; Daumont, L.; Lepère, M.; Vander Auwera, J.

    2011-06-01

    Formaldehyde (H_2CO) is an important intermediate compound in the degradation of the volatile organic compounds (VOCs), including methane, in the terrestrial troposphere. Its observation using optical remote sensing in the infrared range relies on the 3.6 and 5.7 μm absorption bands. Band and individual line intensities have been reported in both ranges. With the present work, we aim to also derive infrared line intensities for formaldehyde, however relying on pure rotation line intensities and the known electric dipole moment to determine the particle density. Indeed, because formaldehyde polymerizes or degrades easily, the gas phase may contain polymerization or degradation products. Spectra of H_2CO diluted in 10 hPa of N_2 were therefore simultaneously recorded in the 20-60 Cm-1 and 3.6 μm ranges, respectively using a Bruker IFS125HR Fourier transform spectrometer and a tunable diode laser. see A. Perrin, D. Jacquemart, F. Kwabia Tchana, N. Lacome, J. Quant. Spectrosc. Radiat. Transfer 110 (2009) 700-716, and references therein

  13. Concomitant contact allergies to formaldehyde, methylchloroisothiazolinone/methylisothiazolinone, methylisothiazolinone, and fragrance mixes I and II.

    Science.gov (United States)

    Pontén, Ann; Bruze, Magnus; Engfeldt, Malin; Hauksson, Inese; Isaksson, Marléne

    2016-11-01

    Contact allergies to the preservatives formaldehyde and methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) have been reported to appear together at a statistically significant level. Recently, revisions concerning the patch test preparations of MCI/MI, MI and formaldehyde have been recommended for the European baseline series. To investigate (i) the number of concomitant contact allergies to the preservatives, (ii) the number of concomitant contact allergies to the preservatives and the fragrance mixes (FM I and FM II) and (iii) gender differences. Patients tested with the Swedish baseline series during the period 2012-2014 at the Department of Occupational and Environmental Dermatology in Malmö, Sweden were investigated. 2165 patients were patch tested with the baseline series (34% males and 66% females). Contact allergies to formaldehyde and MCI/MI and/or MI were significantly associated (p fragrance allergy. Males and females do not differ significantly concerning contact allergy to fragrances. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Metabolic evaluation of skin absorption of tritiated formaldehyde in hairless rats

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, A

    1993-11-01

    Tritiated organics are present as trace impurities in tritium handling facilities. Tritiated formaldehyde has been detected in the atmosphere and gaseous effluents of tritium handling and storage sites. The ability of tritiated formaldehyde to diffuse through the skin is a possible route of intake. Since the metabolism of tritium through this mode of contamination is not currently established, experiments were performed in which tritiated formaldehyde was applied topically on the dorsal skin of hairless rats. These experiments demonstrated that tritium was assimilated and retained in the exposed skin as organically bound tritium (OBT). This retained OBT dominates tritium turnover in the body. OBT retention in the unexposed skin, liver, heart and kidneys was also observed. The loss of tritium from the animals showed that about 10% of the applied tritium was excreted in urine. It is assumed that the rest of the applied activity may have been lost through other excretory pathways, or may not have entered into the body. The biokinetics of tritium excretion is best described by a sum of three exponential functions. Most of the excreted tritium was in the form of OBT (90%) and results in the rapid clearing of OBT in the skin to urine and retention in other tissues. The evaluation of the dose-rate data showed that the dose-rate to exposed skin was almost a magnitude greater than the dose-rate to other organs. (author). 21 refs., 4 tabs., 4 figs.

  15. Formaldehyde roaming dynamics: Comparison of quasi-classical trajectory calculations and experiments.

    Science.gov (United States)

    Houston, Paul L; Wang, Xiaohong; Ghosh, Aryya; Bowman, Joel M; Quinn, Mitchell S; Kable, Scott H

    2017-07-07

    The photodissociation dynamics of roaming in formaldehyde are studied by comparing quasi-classical trajectory calculations performed on a new potential energy surface (PES) to new and detailed experimental results detailing the CO + H 2 product state distributions and their correlations. The new PES proves to be a significant improvement over the past one, now more than a decade old. The new experiments probe both the CO and H 2 products of the formaldehyde dissociation. The experimental and trajectory data offer unprecedented detail about the correlations between internal states of the CO and H 2 dissociation products as well as information on how these distributions are different for the roaming and transition-state pathways. The data investigated include, for dissociation on the formaldehyde 2 1 4 3 band, (a) the speed distributions for individual vibrational/rotational states of the CO products, providing information about the correlated internal energy distributions of the H 2 product, and (b) the rotational and vibrational distributions for the CO and H 2 products as well as the contributions to each from both the transition state and roaming channels. The agreement between the trajectory and experimental data is quite satisfactory, although minor differences are noted. The general agreement provides support for future use of the experimental techniques and the new PES in understanding the dynamics of photodissociative processes.

  16. Synthesis of nano-TiO2/diatomite composite and its photocatalytic degradation of gaseous formaldehyde

    Science.gov (United States)

    Zhang, Guangxin; Sun, Zhiming; Duan, Yongwei; Ma, Ruixin; Zheng, Shuilin

    2017-08-01

    The TiO2/diatomite composite was synthesized through a mild hydrolysis of titanyl sulfate. The prepared composite was characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis diffused reflectance spectroscopy. The results demonstrate that the anatase TiO2 nanopartilces anchored on the surface of diatomite with Ti-O-Si bonds between diatomite and TiO2. The photodegradation of gaseous formaldehyde under UV irradiation by the TiO2/diatomite composite was studied under various operating conditions, including relative humidity, illumination intensity and catalyst amount, which have significant influence on the degradation process. The TiO2/diatomite composite exhibited better photocatalytic activity than pure TiO2, which could be attributed to the favorable nanoparticles dispersibility and strong formaldehyde adsorption capacity. In addition, the composite exhibited outstanding reusability over five cycles. The TiO2/diatomite composite shows great promising application foreground in formaldehyde degradation.

  17. Formaldehyde gas sensor based on TiO2 thin membrane integrated with nano silicon structure

    Science.gov (United States)

    Zheng, Xuan; Ming, An-jie; Ye, Li; Chen, Feng-hua; Sun, Xi-long; Liu, Wei-bing; Li, Chao-bo; Ou, Wen; Wang, Wei-bing; Chen, Da-peng

    2016-07-01

    An innovative formaldehyde gas sensor based on thin membrane type metal oxide of TiO2 layer was designed and fabricated. This sensor under ultraviolet (UV) light emitting diode (LED) illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system (MEMS) processing technology. First, plasma immersion ion implantation (PIII) was adopted to form black polysilicon, then a nanoscale TiO2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.

  18. Field Derived Emission Factors For Formaldehyde and other Volatile Organic Compounds in FEMA Temporary Housing Units

    Energy Technology Data Exchange (ETDEWEB)

    Parthasarathy, Srinandini; Maddalena, Randy L.; Russell, Marion L.; Apte, Michael G.

    2010-10-01

    Sixteen previously occupied temporary housing units (THUs) were studied to assess emissions of volatile organic compounds. The whole trailer emission factors wereevaluated for 36 VOCs including formaldehyde. Indoor sampling was carried out in the THUs located in Purvis staging yard in Mississippi, USA. Indoor temperature andrelative humidity (RH) were also measured in all the trailers during sampling. Indoor temperatures were varied (increased or decreased) in a selection of THUs using theheating, ventilation and air conditioning (HVAC) systems. Indoor temperatures during sampling ranged from 14o C to 33o C, and relative humidity (RH) varied between 35percentand 74percent. Ventilation rates were increased in some trailers using bathroom fans and vents during some of the sampling events. Ventilation rates measured during some aselection of sampling events varied from 0.14 to 4.3 h-1. Steady state indoor formaldehyde concentrations ranged from 10 mu g-m-3 to 1000 mu g-m-3. The formaldehyde concentrations in the trailers were of toxicological significance. The effects of temperature, humidity and ventilation rates were also studied. A linearregression model was built using log of percentage relative humidity, inverse of temperature (in K-1), and inverse log ACH as continuous independent variables, trailermanufacturer as a categorical independent variable, and log of the chemical emission factors as the dependent variable. The coefficients of inverse temperature, log relativehumidity, log inverse ACH with log emission factor were found to be statistically significant for all the samples at the 95percent confidence level. The regression model wasfound to explain about 84percent of the variation in the dependent variable. Most VOC concentrations measured indoors in the Purvis THUs were mostly found to be belowvalues reported in earlier studies by Maddalena et al.,1,2 Hodgson et al.,3 and Hippelein4. Emissions of TMPB-DIB (a plasticizer found in vinyl products) were found

  19. Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage

    International Nuclear Information System (INIS)

    Noda, Taichi; Takahashi, Akihisa; Kondo, Natsuko; Mori, Eiichiro; Okamoto, Noritomo; Nakagawa, Yosuke; Ohnishi, Ken; Zdzienicka, Malgorzata Z.; Thompson, Larry H.; Helleday, Thomas; Asada, Hideo

    2011-01-01

    The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA -/- , FANCC -/- , FANCA -/- C -/- , FANCD2 -/- and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical γH2AX-staining assay. Although the sensitivity of FANCA -/- , FANCC -/- and FANCA -/- C -/- cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2 -/- cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, γH2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex. -- Research highlights: → We examined to clarify the repair pathways of formaldehyde-induced DNA damage. Formaldehyde induces DNA double strand breaks (DSBs). → DSBs are repaired through the Fanconi anemia (FA) repair pathway. → This pathway is independent of the FA nuclear core complex. → We also found that homologous recombination repair was induced by formaldehyde.

  20. Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of Norris Geyser Basin, Yellowstone National Park

    Energy Technology Data Exchange (ETDEWEB)

    Moran, James J.; Whitmore, Laura M.; Isern, Nancy G.; Romine, Margaret F.; Riha, Krystin M.; Inskeep, William P.; Kreuzer, Helen W.

    2016-03-19

    The Norris Geyser Basin in Yellowstone National Park contains a large number of hydrothermal systems, which host microbial populations supported by primary productivity associated with a suite of chemolithotrophic metabolisms. We demonstrate that Metallosphaera yellowstonesis MK1, a facultative autotrophic archaeon isolated from a hyperthermal acidic hydrous ferric oxide (HFO) spring in Norris Geyser Basin, excretes formaldehyde during autotrophic growth. To determine the fate of formaldehyde in this low organic carbon environment, we incubated native microbial mat (containing M. yellowstonensis) from a HFO spring with 13C-formaldehyde. Isotopic analysis of incubation-derived CO2 and biomass showed that formaldehyde was both oxidized and assimilated by members of the community. Autotrophy, formaldehyde oxidation, and formaldehyde assimilation displayed different sensitivities to chemical inhibitors, suggesting that distinct sub-populations in the mat selectively perform these functions. Our results demonstrate that electrons originally resulting from iron oxidation can energetically fuel autotrophic carbon fixation and associated formaldehyde excretion, and that formaldehyde is both oxidized and assimilated by different organisms within the native microbial community. Thus, formaldehyde can effectively act as a carbon and electron shuttle connecting the autotrophic, iron oxidizing members with associated heterotrophic members in the HFO community.

  1. Modeling formalin fixation and histological processing with ribonuclease A: effects of ethanol dehydration on reversal of formaldehyde cross-links.

    Science.gov (United States)

    Fowler, Carol B; O'Leary, Timothy J; Mason, Jeffrey T

    2008-07-01

    Understanding the chemistry of protein modification by formaldehyde fixation and subsequent tissue processing is central to developing improved methods for antigen retrieval in immunohistochemistry and for recovering proteins from formalin-fixed, paraffin-embedded (FFPE) tissues for proteomic analysis. Our initial studies of single proteins, such as bovine pancreatic ribonuclease A (RNase A), in 10% buffered formalin solution revealed that upon removal of excess formaldehyde, monomeric RNase A exhibiting normal immunoreactivity could be recovered by heating at 60 degrees C for 30 min at pH 4. We next studied tissue surrogates, which are gelatin-like plugs of fixed proteins that have sufficient physical integrity to be processed using normal tissue histology. Following histological processing, proteins could be extracted from the tissue surrogates by combining heat, detergent, and a protein denaturant. However, gel electrophoresis revealed that the surrogate extracts contained a mixture of monomeric and multimeric proteins. This suggested that during the subsequent steps of tissue processing protein-formaldehyde adducts undergo further modifications that are not observed in aqueous proteins. As a first step toward understanding these additional modifications we have performed a comparative evaluation of RNase A following fixation in buffered formaldehyde alone and after subsequent dehydration in 100% ethanol by combining gel electrophoresis, chemical modification, and circular dichroism spectroscopic studies. Our results reveal that ethanol-induced rearrangement of the conformation of fixed RNase A leads to protein aggregation through the formation of large geometrically compatible hydrophobic beta-sheets that are likely stabilized by formaldehyde cross-links, hydrogen bonds, and van der Waals interactions. It requires substantial energy to reverse the formaldehyde cross-links within these sheets and regenerate protein monomers free of formaldehyde modifications

  2. Airborne In-Situ Measurements of Formaldehyde over California: One Year of Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    Science.gov (United States)

    Marrero, J. E.; St Clair, J. M.; Yates, E. L.; Ryoo, J. M.; Gore, W.; Swanson, A. K.; Iraci, L. T.; Hanisco, T. F.

    2016-12-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role in multiple atmospheric processes, such as ozone (O3) production in polluted environments. Due to its short lifetime of only a few hours in daytime, HCHO also serves as tracer of recent photochemical activity. While photochemical oxidation of non-methane hydrocarbons is the dominant source, HCHO can also be emitted directly from fuel combustion, vegetation, and biomass burning. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument was built for integration onto the Alpha Jet Atmospheric eXperiment (AJAX) payload, based out of NASA's Ames Research Center (Moffett Field, CA). Using Non-Resonant Laser Induced Fluorescence (NR-LIF), trace concentrations of HCHO can be detected with a sensitivity of 200 parts per trillion. Since its first research flight in December 2015, COFFEE has successfully flown on more than 20 science missions throughout California and Nevada. Presented here are results from these flights, including boundary layer measurements and vertical profiles throughout the tropospheric column. California's San Joaquin Valley is a primary focus, as this region is known for its elevated levels of HCHO as well as O3. Measurements collected in wildfire plumes, urban centers, agricultural lands, and on and off shore comparisons will be presented. In addition, the correlation of HCHO to other trace gases also measured by AJAX, including O3, methane, carbon dioxide, and water vapor will also be shown. Lastly, the implications of these HCHO measurements on calibration and validation of remote sensing data collected by NASA's OMI (Aura) and OMPS (SuomiNPP) satellites will be addressed.

  3. A biodegradable colorimetric film for rapid low-cost field determination of formaldehyde contamination by digital image colorimetry.

    Science.gov (United States)

    Wongniramaikul, Worawit; Limsakul, Wadcharawadee; Choodum, Aree

    2018-05-30

    A biodegradable colorimetric film was fabricated on the lid of portable tube for in-tube formaldehyde detection. Based on the entrapment of colorimetric reagents within a thin film of tapioca starch, the yellow reaction product was observed with formaldehyde. Intensity of the blue channel from the digital image of yellow product showed a linear relationship in the range of 0-25 mg L -1 with low detection limit of 0.7 ± 0.1 mg L -1 . Inter-day precision of 0.61-3.10%RSD were obtained with less than 4.2% relative error from control samples. The developed method was applied for various food samples in Phuket and formaldehyde concentration range was non-detectable to 1.413 mg kg -1 . The quantified concentrations of formaldehyde in fish and squid samples provided relative errors of -7.7% and +10.8% compared to spectrophotometry. This low cost sensor (∼0.04 USD/test) with digital image colorimetry was thus an effective alternative for formaldehyde detection in food sample. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. [Determination of formaldehyde and acetaldehyde in packaging paper by dansylhydrazine derivatization-high performance liquid chromatography-fluorescence detection].

    Science.gov (United States)

    Gong, Shuguo; Liang, Yong; Tang, Liyun; Huang, Ping; Dai, Yunhui

    2017-07-08

    A high performance liquid chromatography with fluorescence detection (HPLC-FLD) method was developed for the simultaneous determination of formaldehyde and acetaldehyde in packaging paper by dansylhydrazine (DNSH) derivatization. The samples were extracted by derivatization reagent for 30 min, and derived for 24 h. After purifying treatment with a PSA/C18 cartridge, a Diamonsil ® C18 column (150 mm×4.6 mm, 5 μ m) was used as stationary phase for separation, the mixtures of acetic acid aqueous solution (pH 2.55)-acetonitrile were used as mobile phases by gradient elution, and the excitation and emission wavelengths were 330 nm and 484 nm, respectively. The results showed that the recoveries of formaldehyde and acetaldehyde spiked in the samples were 81.64%-106.78%, and the relative standard deviations (RSDs) were 2.02%-5.53% ( n =5). The limits of detection of formaldehyde and acetaldehyde were 19.2 μ g/kg and 20.7 μ g/kg, respectively. The limits of quantification of formaldehyde and acetaldehyde were 63.9 μ g/kg and 69.1 μ g/kg, respectively. The method is simple, sensitive and reproducible. It provides a basic approach for the determination of trace formaldehyde and acetaldehyde.

  5. Multicenter Patch Testing With a Resol Resin Based on Phenol and Formaldehyde Within the International Contact Dermatitis Research Group.

    Science.gov (United States)

    Isaksson, Marléne; Ale, Iris; Andersen, Klaus; Diepgen, Thomas; Elsner, Peter; Goossens, An; Goh, Chee-Leok; Jerajani, Hemangi; Maibach, Howard; Matsunaga, Kayoko; McFadden, John; Nixon, Rosemary; Sasseville, Denis; Bruze, Magnus

    2015-01-01

    Contact allergy to phenol-formaldehyde resins (PFRs) based on phenol and formaldehyde is not detected by a p-tertiary-butylphenol-formaldehyde resin included in most baseline patch test series. The aims of this study were to investigate the contact allergy rate to PFR-2 in an international population and to investigate associated simultaneous allergic reactions. Thirteen centers representing the International Contact Dermatitis Research Group included PFR-2 into their patch test baseline series during a period of 6 months in 2012. Of 2259 patients tested, 28 (1.2%) reacted to PFR-2. Of those 28 individuals, one had a positive reaction to formaldehyde and 2 to p-tertiary-butylphenol-formaldehyde resin. Simultaneous allergic reactions were noted to colophonium in 3, to Myroxylon pereirae in 5, and to fragrance mix I in 8. The contact allergy frequency in the tested population (1.2%) merits its inclusion into the international baseline series and possibly also into other baseline series after appropriate investigations. Significantly, overrepresented simultaneous allergic reactions were noted for M. pereirae and fragrance mix I.

  6. Optimization of Formaldehyde Cross-Linking for Protein Interaction Analysis of Non-Tagged Integrin β1

    Directory of Open Access Journals (Sweden)

    Cordula Klockenbusch

    2010-01-01

    Full Text Available Formaldehyde cross-linking of protein complexes combined with immunoprecipitation and mass spectrometry analysis is a promising technique for analysing protein-protein interactions, including those of transient nature. Here we used integrin β1 as a model to describe the application of formaldehyde cross-linking in detail, particularly focusing on the optimal parameters for cross-linking, the detection of formaldehyde cross-linked complexes, the utility of antibodies, and the identification of binding partners. Integrin β1 was found in a high molecular weight complex after formaldehyde cross-linking. Eight different anti-integrin β1 antibodies were used for pull-down experiments and no loss in precipitation efficiency after cross-linking was observed. However, two of the antibodies could not precipitate the complex, probably due to hidden epitopes. Formaldehyde cross-linked complexes, precipitated from Jurkat cells or human platelets and analyzed by mass spectrometry, were found to be composed of integrin β1, α4 and α6 or β1, α6, α2, and α5, respectively.

  7. Optimization of Formaldehyde Cross-Linking for Protein Interaction Analysis of Non-Tagged Integrin β1

    Science.gov (United States)

    Klockenbusch, Cordula; Kast, Juergen

    2010-01-01

    Formaldehyde cross-linking of protein complexes combined with immunoprecipitation and mass spectrometry analysis is a promising technique for analysing protein-protein interactions, including those of transient nature. Here we used integrin β1 as a model to describe the application of formaldehyde cross-linking in detail, particularly focusing on the optimal parameters for cross-linking, the detection of formaldehyde cross-linked complexes, the utility of antibodies, and the identification of binding partners. Integrin β1 was found in a high molecular weight complex after formaldehyde cross-linking. Eight different anti-integrin β1 antibodies were used for pull-down experiments and no loss in precipitation efficiency after cross-linking was observed. However, two of the antibodies could not precipitate the complex, probably due to hidden epitopes. Formaldehyde cross-linked complexes, precipitated from Jurkat cells or human platelets and analyzed by mass spectrometry, were found to be composed of integrin β1, α4 and α6 or β1, α6, α2, and α5, respectively. PMID:20634879

  8. Influence of precision of emission characteristic parameters on model prediction error of VOCs/formaldehyde from dry building material.

    Directory of Open Access Journals (Sweden)

    Wenjuan Wei

    Full Text Available Mass transfer models are useful in predicting the emissions of volatile organic compounds (VOCs and formaldehyde from building materials in indoor environments. They are also useful for human exposure evaluation and in sustainable building design. The measurement errors in the emission characteristic parameters in these mass transfer models, i.e., the initial emittable concentration (C 0, the diffusion coefficient (D, and the partition coefficient (K, can result in errors in predicting indoor VOC and formaldehyde concentrations. These errors have not yet been quantitatively well analyzed in the literature. This paper addresses this by using modelling to assess these errors for some typical building conditions. The error in C 0, as measured in environmental chambers and applied to a reference living room in Beijing, has the largest influence on the model prediction error in indoor VOC and formaldehyde concentration, while the error in K has the least effect. A correlation between the errors in D, K, and C 0 and the error in the indoor VOC and formaldehyde concentration prediction is then derived for engineering applications. In addition, the influence of temperature on the model prediction of emissions is investigated. It shows the impact of temperature fluctuations on the prediction errors in indoor VOC and formaldehyde concentrations to be less than 7% at 23±0.5°C and less than 30% at 23±2°C.

  9. Adsorption of formaldehyde molecule on the pristine and transition metal doped graphene: First-principles study

    International Nuclear Information System (INIS)

    Chen, Xin; Xu, Lei; Liu, Lin-Lin; Zhao, Lu-Si; Chen, Chun-Ping; Zhang, Yong; Wang, Xiao-Chun

    2017-01-01

    Highlights: • Formaldehyde molecule (H_2CO) is a common environmental pollutant with strong toxicity. • Total 36 different initial configurations of H_2CO molecule adsorbing onto three types of substrates have been investigated. • The Ti-doped graphene has the enough binding energy, significant changes in electronic structure, and reasonable short recovery time 10"−"3 s. • The Ti-doped graphene is a promising candidate for detecting formaldehyde gas. - Abstract: The adsorption of H_2CO molecule on pristine and transition metal (Ti and V) doped graphene samples were investigated via a first-principles approach based on density functional theory. The most stable adsorption geometry, energy and charge transfer of H_2CO molecule on pristine and doped graphene are discussed respectively. We have found that Ti and V dopant atoms can significantly enhance the interaction between H_2CO molecule and graphene. The calculated net electron transfers, electronic density difference images and densities of states give the evidence that the H_2CO molecules stay on Ti (or V) – doped graphene by chemisorption. After H_2CO adsorption, there are significant changes in electronic structure near the Fermi level, for both two systems of Ti and V doped graphene. This indicates distinct changes of electron transport properties. We have also found that H_2CO molecule has a larger absorption energy on V-doped graphene (1.939 eV) compared with Ti-doped graphene (1.120 eV). It is shown that the Ti-doped graphene has enough binding energy, adequate changes in electronic structure and reasonable short recovery time 10"−"3 s, making it a promising candidate for detecting formaldehyde gas.

  10. Formaldehyde exposure in U.S. industries from OSHA air sampling data.

    Science.gov (United States)

    Lavoue, Jerome; Vincent, Raymond; Gerin, Michel

    2008-09-01

    National occupational exposure databanks have been cited as sources of exposure data for exposure surveillance and exposure assessment for occupational epidemiology. Formaldehyde exposure data recorded in the U.S Integrated Management Information System (IMIS) between 1979 and 2001 were collected to elaborate a multi-industry retrospective picture of formaldehyde exposures and to identify exposure determinants. Due to the database design, only detected personal measurement results (n = 5228) were analyzed with linear mixed-effect models, which explained 29% of the total variance. Short-term measurement results were higher than time-weighted average (TWA) data and decreased 18% per year until 1987 (TWA data 5% per year) and 5% per year (TWA data 4% per year) after that. Exposure varied across industries with maximal estimated TWA geometric means (GM) for 2001 in the reconstituted wood products, structural wood members, and wood dimension and flooring industries (GM = 0.20 mg/m(3). Highest short-term GMs estimated for 2001 were in the funeral service and crematory and reconstituted wood products industries (GM = 0.35 mg/m(3). Exposure levels in IMIS were marginally higher during nonprogrammed inspections compared with programmed inspections. An increasing exterior temperature tended to cause a decrease in exposure levels for cold temperatures (-5% per 5 degrees C for T 15 degrees C). Concentrations measured during the same inspection were correlated and varied differently across industries and sample type (TWA, short term). Sensitivity analyses using TOBIT regression suggested that the average bias caused by excluding non-detects is approximately 30%, being potentially higher for short-term data if many non-detects were actually short-term measurements. Although limited by availability of relevant exposure determinants and potential selection biases in IMIS, these results provide useful insight on formaldehyde occupational exposure in the United States in the last

  11. Adsorption of formaldehyde molecule on the pristine and transition metal doped graphene: First-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xin [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); Xu, Lei [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); College of Physics, Jilin University, Changchun, 130012 (China); Liu, Lin-Lin; Zhao, Lu-Si; Chen, Chun-Ping [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012 (China); Zhang, Yong [Department of Electrical and Computer Engineering, The University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); Wang, Xiao-Chun, E-mail: wangxiaochun@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012 (China)

    2017-02-28

    Highlights: • Formaldehyde molecule (H{sub 2}CO) is a common environmental pollutant with strong toxicity. • Total 36 different initial configurations of H{sub 2}CO molecule adsorbing onto three types of substrates have been investigated. • The Ti-doped graphene has the enough binding energy, significant changes in electronic structure, and reasonable short recovery time 10{sup −3} s. • The Ti-doped graphene is a promising candidate for detecting formaldehyde gas. - Abstract: The adsorption of H{sub 2}CO molecule on pristine and transition metal (Ti and V) doped graphene samples were investigated via a first-principles approach based on density functional theory. The most stable adsorption geometry, energy and charge transfer of H{sub 2}CO molecule on pristine and doped graphene are discussed respectively. We have found that Ti and V dopant atoms can significantly enhance the interaction between H{sub 2}CO molecule and graphene. The calculated net electron transfers, electronic density difference images and densities of states give the evidence that the H{sub 2}CO molecules stay on Ti (or V) – doped graphene by chemisorption. After H{sub 2}CO adsorption, there are significant changes in electronic structure near the Fermi level, for both two systems of Ti and V doped graphene. This indicates distinct changes of electron transport properties. We have also found that H{sub 2}CO molecule has a larger absorption energy on V-doped graphene (1.939 eV) compared with Ti-doped graphene (1.120 eV). It is shown that the Ti-doped graphene has enough binding energy, adequate changes in electronic structure and reasonable short recovery time 10{sup −3} s, making it a promising candidate for detecting formaldehyde gas.

  12. Microencapsulation of a fatty acid with Poly(melamine–urea–formaldehyde)

    International Nuclear Information System (INIS)

    Konuklu, Yeliz; Paksoy, Halime O.; Unal, Murat; Konuklu, Suleyman

    2014-01-01

    Highlights: • Decanoic(capric) acid microcapsules were prepared with different capsule wall materials. • The one-step in situ polymerization technique was used. • Leakage-free, thermally stable microPCMs was prepared with Poly(MUF). • Influence of different surfactants on encapsulation and thermal properties reported. - Abstract: The main purpose of this study is to obtain leakage-free, thermally stable decanoic acid microcapsules (microPCMs) for thermal energy storage applications. Decanoic acid (capric acid) is an environmentally friendly fatty acid since it is obtained from vegetable and animal oils. MicroPCMs were prepared with different capsule wall materials via a one-step in situ polymerization technique. The properties of microencapsulated PCMs have been analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analyzer (TGA), Fourier transform infrared (FTIR) spectra analysis and particle size analyzer. The microPCMs prepared using Poly(urea–formaldehyde) (PUF) exhibit higher heat capacities and the microPCMs prepared using Poly(melamine–formaldehyde) (PMF) exhibit higher thermal stabilities. In order to obtain microPCMs with better properties such as suitable latent heat and better heat resistance at high temperatures, we microencapsulated decanoic acid with Poly (melamine–urea–formaldehyde) (PMUF). Furthermore, the effects of surfactants on microPCMs with PMUF were investigated by SEM, a particle size analyzer, DSC, and TGA. The results show that the binary surfactant system was a suitable emulsifier for this process. We determined that the melting temperature was close to 33 °C, the latent heat storage capacity was about 88 J/g, and the mean particle diameter was 0.28 μm for microPCMs with PMUF. We recommend decanoic acid microencapsulated with PMUF for thermally stable and leakage-free applications above 95 °C

  13. Using microkinetic analysis to search for novel anhydrous formaldehyde production catalysts

    DEFF Research Database (Denmark)

    Li, Han-Jung; Lausche, Adam C.; Peterson, Andrew A.

    2015-01-01

    Abstract Direct dehydrogenation of methanol to produce anhydrous formaldehyde is investigated using periodic density functional theory (DFT) and combining the microkinetic model to estimate rates and selectivities on stepped (211) surfaces under a desired reaction condition. Binding energies...... that explicitly includes the effects of adsorbate coverage on the rates and selectivities as well as the volcano plots are obtained. Our results show that most of the stepped (211) pure-metallic surfaces such as Au, Pt, Pd, Rh, Ru, Ni, Fe, and Co are located in a region of low activity and selectivity toward CH2O...

  14. Calculation of kinetic parameters of amino-formaldehyde polymers formation in the presence of calcium ions

    Directory of Open Access Journals (Sweden)

    V.V. Arhipova

    2016-05-01

    Full Text Available Calcium carbonate is on of widely used fillers of composite materials. The area of its application depend on disperse structure, particle shape and other. The modification of calcium carbonate by high-molecular polymers allows changing its characteristics and surface properties in a wide range. The modification of calcium carbonate often carried out with use of amino-formaldehyde polymers (AFP. Aim: The aim of this work is to determine the kinetic characteristics of amino-formaldehyde polymers polycondensation process in the presence of calcium ions. Materials and Methods: The mechanism of AFP polycondensation is complex and depends on various factors. Polycondensation of AFP took place under following conditions: the temperature is 20, 30, 60°C; the molar ratio of carbamide to formaldehyde is 1:1.25; the polycondensation duration is 2 hours; the mass ratio of CaCO3:AFP = 1:1. The polycondensation process was carried out in calcium chloride solution with рН=2…5.5. The concentration of formaldehyde and metilol groups determined during the experiment using chemical titrimetric method. Results: It is shown that polycondensation process of AFP in the presence of Сa2+ ions at their concentration from 0 to 2,25 mol/l (0…90 g/l leads to acceleration of process more than by 1.8 times at temperature of 20°C. Further increase of Сa2+ concentration leads to reduction of process speed. At temperature of 30°C the speed of process almost does not change in the range of Сa2+ concentration from 0 to 2,25 mol/l and further decreases slightly. For all range of Сa2+ concentration at temperature of 60°C the reduction of process speed is observed. Influence of Сa2+ on process of polycondensation confirms assumption made earlier of formation of weak bonds between AFP and calcium ions which at low temperatures interfere with hydrolysis of methyleneurea and collapse at increasing of process temperature.

  15. Impact of the formaldehyde concentration in the air on the sink effect of a coating material

    Directory of Open Access Journals (Sweden)

    Tiffonnet Anne-Lise

    2018-01-01

    Full Text Available This study aims to characterize, from a numerical modelling, the sorption behaviour of a material (a plasticised flooring material when it is exposed to a pollutant commonly encountered in indoor environments (formaldehyde. It deals with the influence of the pollutant concentration in the room air on the sink effect of the material. The numerical simulations are based on a macroscopic modelling using experimental test results obtained elsewhere. The consequences on the room inertia are also discussed, and analogies between mass transfer and heat transfer are highlighted.

  16. Flame Front Detection Using Formaldehyde Laser Induced Fluorescence In Turbulent Lean Premixed Flames

    Energy Technology Data Exchange (ETDEWEB)

    Schenker, S.; Tylli, N.; Bombach, R.

    2005-03-01

    The present work aims at suggesting the excitation-detection scheme best suited for laser-induced fluorescence measurements of formaldehyde in turbulent lean premixed flames. In the literature, three different excitation schemes within the A{sup 1} X{sup 1} electronic transition have been suggested, with excitation into the 2{sup 1}{sub 0} 4{sup 1}{sub 0} , 4{sup 1}{sub 0} , and 4{sup 0}{sub 1} vibratoric bands, respectively. These excitation schemes were tested systematically and both advantages and disadvantages for each scheme are discussed. (author)

  17. Discovery of a cyclic 6 + 6 hexamer of d-biotin and formaldehyde

    DEFF Research Database (Denmark)

    Lisbjerg, Micke; Jessen, Bo M.; Rasmussen, Brian

    2014-01-01

    The discovery of receptors using templated synthesis enables the selection of strong receptors from complex mixtures. In this contribution we describe a study of the condensation of d-biotin and formaldehyde in acidic water. We have discovered that halide anions template the formation of a single...... isomer of a 6 + 6 macrocycle. The macrocycle (biotin[6]uril) is water-soluble, chiral and binds halide anions (iodide, bromide and chloride) with selectivity for iodide in water, and it can be isolated on a gram scale in a one-pot reaction in 63% yield....

  18. Quantum Cascade Laser-Based Photoacoustic Sensor for Trace Detection of Formaldehyde Gas

    Directory of Open Access Journals (Sweden)

    Pietro Mario Lugarà

    2009-04-01

    Full Text Available We report on the development of a photoacoustic sensor for the detection of formaldehyde (CH2O using a thermoelectrically cooled distributed-feedback quantum cascade laser operating in pulsed mode at 5.6 mm. A resonant photoacoustic cell, equipped with four electret microphones, is excited in its first longitudinal mode at 1,380 Hz. The absorption line at 1,778.9 cm-1 is selected for CH2O detection. A detection limit of 150 parts per billion in volume in nitrogen is achieved using a 10 seconds time constant and 4 mW laser power. Measurements in ambient air will require water vapour filters.

  19. Assessing the Levels and Health Risk of Atmospheric Formaldehyde in Makkah, Saudi Arabia

    OpenAIRE

    Atef M.F. Mohammed; Essam A. Morsy; Turki M. Habeebullah; Said Munir

    2015-01-01

    Atmospheric Formaldehyde (HCHO) was monitored in four sites on the Holy Mosque of Makkah, Saudi Arabia during August, 2013. The daily mean concentrations of HCHO were ranged from 1.09-18.92 g/m3. The levels of HCHO were significantly higher than the permissible exposure limit (0.042 μg/m3) of the Occupational Safety and Health Administration (OSHA). However, it were not exceeded the recommended exposure limit of the National Institute for Occupational Safety and Health (20 μg/m3) and Egyptian...

  20. HPLC Characterization of Phenol-Formaldehyde Resole Resin Used in Fabrication of Shuttle Booster Nozzles

    Science.gov (United States)

    Young, Philip R.

    1999-01-01

    A reverse phase High Performance Liquid Chromatographic method was developed to rapidly fingerprint a phenol-formaldehyde resole resin similar to Durite(R) SC-1008. This resin is used in the fabrication of carbon-carbon composite materials from which Space Shuttle Solid Rocket Booster nozzles are manufactured. A knowledge of resin chemistry is essential to successful composite processing and performance. The results indicate that a high quality separation of over 35 peaks in 25 minutes were obtained using a 15 cm Phenomenex LUNA C8 bonded reverse phase column, a three-way water-acetonitrile-methanol nonlinear gradient, and LTV detection at 280 nm.

  1. Measurement of emissions during the crosslinking of phenolic resins. Problems with cross-sensibility when determining formaldehyde. Messung von Emissionen bei der Aushaertung von Phenolharzen. Probleme durch Querempfindlichkeiten bei der Bestimmung von Formaldehyd

    Energy Technology Data Exchange (ETDEWEB)

    Haub, H.G.; Muehlhauser, S.; Mueller, F.J.; Gardziella, A. (Bakelite GmbH, Iserlohn (Germany, F.R.))

    1988-04-01

    Phenol and formol (37-50% aqueous solution of formaldehyde) are the main raw materials for the production of phenolic resins. Hexamethylene tetramine is the common constituent for crosslinking when processing phenol novolaks. Most of the today colorimetric methods for the determination of formaldehyde have a strong cross sensibility to hexamethylene tetramine. The error may be 1-2 powers of ten. The only exception is the AHMT-method. Hexamethylene tetramine-containing phenolic resin systems are required for grinding and friction materials, for textile fibre mass and in the foundry industries (croning process). These systems are also used for refractories, for impregnation and for producing carbon and graphite materials. (orig.).

  2. Quantitative relationship between trimethylamine-oxide aldolase activity and formaldehyde accumulation in white muscle from gadiform fish during frozen storage

    DEFF Research Database (Denmark)

    Nielsen, Michael Krogsgaard; Jørgensen, Bo

    2004-01-01

    for by the endogenous white muscle in situ TMAOase activity. This TMAOase activity also correlated with the rate of insolubilization of otherwise high ionic strength soluble protein. A simple model describing the accumulation of free formaldehyde during frozen storage of gadiform fish is proposed. The model is based......The accumulation of formaldehyde and the resulting deterioration of seafood products during frozen storage are primarily caused by the enzymatic activity of trimethylamine oxide aldolase (TMAOase). A screening of muscle samples from 24 species showed TMAOase activity in only the nine gadiform...... species that were analyzed. Enzyme activities in the major white muscle of gadiform fish showed large variations between species as well as between individuals. A frozen storage experiment showed a similarly large variation in the rate of formaldehyde accumulation, which could be accounted...

  3. Forensic Investigation of Formaldehyde in Illicit Products for Hair Treatment by DAD-HPLC: A Case Study.

    Science.gov (United States)

    Oiye, Erica N; Ribeiro, Maria Fernanda M; Okumura, Leonardo L; Saczk, Adelir A; Ciancaglini, Pietro; de Oliveira, Marcelo F

    2016-07-01

    The illegal use of formalin (commercial formaldehyde) in cosmetic products harms the health of individuals exposed to this substance. Over the last years, the commercial availability of these products, especially those containing irregular dosage of formaldehyde, has increased in Brazil. This work analyzes some products for hair treatment available in the Brazilian market and verifies their safety. The adopted analytical methodology involved sample derivatization with 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography with ultraviolet detection (UV-VIS) at λ = 365 nm. The limit of quantification is 2.5 × 10 -3% w/w, and the recovery tests were around 93%. Some of the samples contained high and illegal formaldehyde levels ranging from 9% to 19% (w/w) and others presented suitable concentrations of the analyte. On the basis of the results, this work discusses the efficiency and practicality of this analytical method for forensic purposes. © 2016 American Academy of Forensic Sciences.

  4. Oxidation of methanol to formaldehyde over a series of Fe1-xAlx-V-oxide catalysts

    DEFF Research Database (Denmark)

    Häggblad, Robert; Wagner, Jakob Birkedal; Hansen, Staffan

    2008-01-01

    A series of triclinic Fe1−xAlxVO4 phases with 0x1 were prepared and used in the oxidation of methanol to formaldehyde. The activity measurements revealed that both the activity and especially the selectivity to formaldehyde increased with time of operation for at least 16 h, indicating...... restructuring of the catalysts. Characterisation of the catalysts with XRD, XANES, and electron microscopy after use in methanol oxidation showed that the stability of the bulk phases improved when Al was substituted for Fe in the structure. XRD and XANES of the used FeVO4 showed that it partly transformed...... in methanol oxidation revealed no significant change in the metal composition, in good agreement with the corresponding bulk values, except for a lower Fe value. Steady-state activity data showed a modest increase in specific activity with the Al content, whereas the selectivity to formaldehyde was about 90...

  5. Henry’s Law Constant and Overall Mass Transfer Coefficient for Formaldehyde Emission from Small Water Pools under Simulated Indoor Environmental Conditions

    Science.gov (United States)

    The Henry’s law constant (HLC) and the overall mass transfer coefficient are both important parameters for modeling formaldehyde emissions from aqueous solutions. In this work, the apparent HLCs for aqueous formaldehyde solutions were determined in the concentration range from 0....

  6. Determination of Very Low Level of Free Formaldehyde in Liquid Detergents and Cosmetic Products Using Photoluminescence Method

    Directory of Open Access Journals (Sweden)

    Ali Gholami

    2016-01-01

    Full Text Available Formaldehyde is commonly used in detergents and cosmetic products as antibacterial agent and preservative. This substance is unfavorable for human health because it is known to be toxic for humans and causes irritation of eyes and skins. The toxicology studies of this compound indicate risk of detergents and cosmetic formulations with a minimum content of 0.05% free formaldehyde. Therefore, determination of formaldehyde as quality control parameter is very important. In this study, a photoluminescence method was achieved by using 2-methyl acetoacetanilide. Also, the Box-Behnken design was applied for optimization of Hantzsch reaction for formaldehyde derivatization. The investigated factors (variables were temperature, % v/v ethanol, reaction time, ammonium acetate, and 2-methyl acetoacetanilide concentration. The linear range was obtained from 0.33–20 × 10−7 M (1–60 μg·kg−1 and the limit of detection (LOD was 0.12 μg·kg−1. The proposed method was applied for the analysis of Iranian brands of liquid detergents and cosmetic products. The formaldehyde content of these products was found to be in the range of 0.03–3.88%. Some brands of these products had higher concentration than the maximum allowed concentration of 0.2%. High recoveries (96.15%–104.82% for the spiked dishwashing liquid and hair shampoo indicate the proposed method is proper for the assessment of formaldehyde in detergents and cosmetic products. The proposed methodology has some advantages compared with the previous methods such as being rapid, without the necessity of applying separation, low cost, and the fact that the derivatization reaction is carried out at room temperature without any heating system.

  7. Co-Adsorption of Ammonia and Formaldehyde on Regenerable Carbon Sorbents for the Primary Life Support System (PLSS)

    Science.gov (United States)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique S.

    2016-01-01

    Results are presented on the development of a reversible carbon sorbent for trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is deemed non-regenerable, while the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on concurrent sorption and desorption of ammonia and formaldehyde, which are major TCs of concern, are presented in this paper. A carbon sorbent was fabricated by dry impregnation of a reticulated carbon-foam support with polyvinylidene chloride, followed by carbonization and thermal oxidation in air. Sorbent performance was tested for ammonia and formaldehyde sorption and vacuum regeneration, with and without water present in the gas stream. It was found that humidity in the gas phase enhanced ammonia-sorption capacity by a factor larger than two. Co-adsorption of ammonia and formaldehyde in the presence of water resulted in strong formaldehyde sorption (to the point that it was difficult to saturate the sorbent on the time scales used in this study). In the absence of humidity, adsorption of formaldehyde on the carbon surface was found to impair ammonia sorption in subsequent runs; in the presence of water, however, both ammonia and formaldehyde could be efficiently removed from the gas phase by the sorbent. The efficiency of vacuum regeneration could be enhanced by gentle heating to temperatures below 60 deg.

  8. Cystathionine metabolic enzymes play a role in the inflammation resolution of human keratinocytes in response to sub-cytotoxic formaldehyde exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eunyoung [College of Pharmacy, Seoul National University, Seoul 08826 (Korea, Republic of); Natural Products Research Institute, Seoul National University, Seoul 08826 (Korea, Republic of); Kim, Hyoung-June [Basic Research and Innovation Division, AmorePacific Corporation R& D Center, Yongin, Gyeounggi-do 17074 (Korea, Republic of); Lee, Moonyoung [College of Pharmacy, Seoul National University, Seoul 08826 (Korea, Republic of); Jin, Sun Hee; Hong, Soo Hyun; Ahn, Seyeon; Kim, Sae On [College of Pharmacy, Seoul National University, Seoul 08826 (Korea, Republic of); Natural Products Research Institute, Seoul National University, Seoul 08826 (Korea, Republic of); Shin, Dong Wook [Basic Research and Innovation Division, AmorePacific Corporation R& D Center, Yongin, Gyeounggi-do 17074 (Korea, Republic of); Lee, Seung-Taek [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722 (Korea, Republic of); Noh, Minsoo, E-mail: minsoonoh@snu.ac.kr [College of Pharmacy, Seoul National University, Seoul 08826 (Korea, Republic of); Natural Products Research Institute, Seoul National University, Seoul 08826 (Korea, Republic of)

    2016-11-01

    Low-level formaldehyde exposure is inevitable in industrialized countries. Although daily-life formaldehyde exposure level is practically impossible to induce cell death, most of mechanistic studies related to formaldehyde toxicity have been performed in cytotoxic concentrations enough to trigger cell death mechanism. Currently, toxicological mechanisms underlying the sub-cytotoxic exposure to formaldehyde are not clearly elucidated in skin cells. In this study, the genome-scale transcriptional analysis in normal human keratinocytes (NHKs) was performed to investigate cutaneous biological pathways associated with daily life formaldehyde exposure. We selected the 175 upregulated differentially expressed genes (DEGs) and 116 downregulated DEGs in NHKs treated with 200 μM formaldehyde. In the Gene Ontology (GO) enrichment analysis of the 175 upregulated DEGs, the endoplasmic reticulum (ER) unfolded protein response (UPR) was identified as the most significant GO biological process in the formaldeyde-treated NHKs. Interestingly, the sub-cytotoxic formaldehyde affected NHKs to upregulate two enzymes important in the cellular transsulfuration pathway, cystathionine γ-lyase (CTH) and cystathionine-β-synthase (CBS). In the temporal expression analysis, the upregulation of the pro-inflammatory DEGs such as MMP1 and PTGS2 was detected earlier than that of CTH, CBS and other ER UPR genes. The metabolites of CTH and CBS, L-cystathionine and L-cysteine, attenuated the formaldehyde-induced upregulation of pro-inflammatory DEGs, MMP1, PTGS2, and CXCL8, suggesting that CTH and CBS play a role in the negative feedback regulation of formaldehyde-induced pro-inflammatory responses in NHKs. In this regard, the sub-cytotoxic formaldehyde-induced CBS and CTH may regulate inflammation fate decision to resolution by suppressing the early pro-inflammatory response. - Highlights: • Sub-cytotoxic formaldehyde upregulates ER UPR-associated genes in NHKs. • Formaldehyde-induced ER UPR

  9. The effect of occupational exposure to formaldehyde on blood platelets of employees in a wood industry company

    Directory of Open Access Journals (Sweden)

    2013-02-01

    Full Text Available Introduction: Existing literatures indicate that occupational exposure to formaldehyde may decrease blood platelets. In this study, the influences of occupational exposure to formaldehyde on the number of blood plateletsand clinical symptoms were studied while determining the occupational exposure of employees of a wood industry to formaldehyde. .Material and Method: In a case study, the occupational exposure to formaldehyde was determined among 30 workers from production line and 30 administrative staffs of a wood company using US-NIOSH method No 2541. The number of blood platelets was determined using the normal blood count method and related indices. Demographic data as well as the clinical symptoms of exposure to formaldehyde were collected using a standard questionnaire. The smokers and those using drugs interacting with similar symptoms and blood characteristics were excluded from the study. Ethical principles for medical research involving human subjects announced in Helsinki declaration were considered. The research proposal had been approved by the university committee of ethics prior to its execution. Details of tests were explained for all subjects and a written consent was signed by each subject. .Result: Occupational exposure of workers in various parts of particle board production line ranged from 0.5 ppm to 1.52 ppm which was higher than the ceiling level (0.3 ppm recommended by US-ACGIH. The prevalence of all studied symptoms from formaldehyde exposure in workers was significantly higher than the administrative staffs. In case group, tearing rate was the highest average 8.98 while the chest pain with an average rate of 3.20 was the lowest. In control group, the prevalence of coughing with an average rate of 6.62 was the highest and the chest pain with an average rate of 5.53 was the lowest. The average number and standard deviation of blood platelets of workers in production line and staffs were statistically different with the

  10. Trace gas sensing using quantum cascade lasers and a fiber-coupled optoacoustic sensor: Application to formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Elia, A; Lugara, P M; Scamarcio, G [CNR-INFM Regional Laboratory LIT and Dipartimento Interateneo di Fisica, Universita di Bari, via Amendola 173, 70126 Bari (Italy); Spagnolo, V [CNR-INFM Regional Laboratory LIT and Dipartimento Interateneo di Fisica, Politecnico di Bari, via Amendola 173, 70126 Bari (Italy); Di Franco, C, E-mail: spagnolo@fisica.uniba.i [CNR-INFM Regional Laboratory LIT, via Amendola 173, 70126 Bari (Italy)

    2010-03-01

    We will report here on the design and realization of an optoacoustic sensor for the detection of formaldehyde. The sensor consists of a commercial QCL and a resonant PA cell. Two different cell configurations have been investigated: a 'standard' H cell and an innovative T-cell with an optical fiber directly inserted into. Two different type of sound detector have been employed: electret microphones and optical MEMS-based microphone. As possible applications, we will describe the results obtained in the detection of formaldehyde (CH{sub 2}O), a gas of great interest for industrial processes and environmental monitoring.

  11. NIOSH comments to DOL on the Occupational Safety and Health Administration's proposed rule on occupational exposure to formaldehyde by R. A. Lemen, June 27, 1986

    International Nuclear Information System (INIS)

    1986-01-01

    NIOSH presented posthearing comments on formaldehyde (50000) including materials which NIOSH indicated it would supply during the testimony, answers to questions which were addressed to the NIOSH panel members at the hearing, and related issues on which NIOSH wanted to expand. Topics included: epidemiologic and industrial hygiene studies of workers exposed to formaldehyde; the percentage of garment manufacturing locations sampled; the facilities studied in the SMR and PMR studies; data from the NIOSH garment manufacturing study; quantitative trend analysis of exposure level and latency; an evaluation conducted by Nelson Leidel; the effects of mixed exposure to formaldehyde and wood dust on cancer incidence; the most recent lists of approved respirators and field test methods for chemical protective clothing; the deposition of radiolabeled formaldehyde; formaldehyde exposure values in other industries; malignant neoplasms of the nervous system; the NIOSH carcinogenesis policy; hyposmia; variations in expected cancer patterns; and the observed pattern of excess lung cancer mortality

  12. EFFECT OF WOOD SPECIES USED FOR CORE LAYER ON SOME PROPERTIES OF OKUME PLYWOOD PANELS BONDED WITH MELAMINE-UREA FORMALDEHYDE (MUF ADHESIVE

    Directory of Open Access Journals (Sweden)

    Cenk Demirkır

    2005-04-01

    Full Text Available In this study; changes in some properties of the okume plywood panels when used alder and beech veneers in their core layers were investigated. Two types of melamine-urea formaldehyde (MUF resins having different free formaldehyde contents were used for bonding plywood panels manufactured from 2 mm thick veneers at industrial conditions. The formaldehyde emission values of plywood panels bonded with MÜF having higher free formaldehyde content were found to be higher than those of the panels bonded with other resin type. The highest formaldehyde emission value was found for the panels manufactured from okume veneers in all layers while the lowest value was determined from the panels include beech veneers in the core layer. The shear and bending strength values of the panels consisted of beech veneers in the core layer were found to be higher than those of the panels consisted of okume and alder veneers in the core layers.

  13. Preconcentration of trace amounts of formaldehyde from water, biological and food samples using an efficient nanosized solid phase, and its determination by a novel kinetic method

    International Nuclear Information System (INIS)

    Afkhami, A.; Bagheri, H.

    2012-01-01

    This work presents a sensitive method for the determination of formaldehyde. It is based on the use of modified alumina nanoparticles for its preconcentration, this followed by a new and simple catalytic kinetic method for its determination. Alumina nanoparticles were chemically modified by immobilization of 2,4-dinitrophenylhydrazine via sodium dodecyl sulfate as a surfactant. The formaldehyde retained on the modified adsorbent was then desorbed and determined via its catalytic effect on the oxidation of thionine by bromate ion. Factors affecting the preconcentration and determination of formaldehyde have been investigated. Formaldehyde can be detected in the range from 0. 05 to 38. 75 μg L -1 , and no serious interferences have been observed. The method has been successfully applied to the quantitation of formaldehyde in water, food, and certain biological samples. (author)

  14. Novel Reaction of N,N'-Bisarylmethanediamines with Formaldehyde. Synthesis of Some New 1,3,5-Triaryl-1,3,5-hexahydrotriazines

    Directory of Open Access Journals (Sweden)

    Abolfazl Olyaei

    2006-07-01

    Full Text Available The acid-catalyzed cyclocondensation of N,N'-bisaryl (aryl = 2-pyrimidinyl, 2- pyrazinyl and 4-nitrophenyl methanediamines 5a-c with aqueous formaldehyde in refluxing acetonitrile leads to the formation of the corresponding 1,3,5-triaryl-1,3,5-hexa- hydrotriazines 6a-c. The stoichiometric reactions of 2-aminopyrimidine and 2-amino- pyrazine with aqueous formaldehyde in acetonitrile under reflux conditions also afforded 6a and 6b, respectively. Treatment of 2-aminopyrimidine with aqueous formaldehyde in a 3:2 ratio yielded N,N',N"-tris(2-pyrimidinyldimethylenetriamine (7a as a sole product, which upon subsequent reaction with formaldehyde also afforded 6a. The reaction of N,N'-biphenylmethanediamine with formaldehyde was also investigated.

  15. Concentrating cesium-137 from seawater using resorcinol-formaldehyde resin for radioecological monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Egorin, Andrei; Tokar, Eduard; Tutov, Mikhail; Avramenko, Valentin [Institute of Chemistry FEBRAS, Vladivostok (Russian Federation); Far Eastern Federal Univ., Vladivostok (Russian Federation); Palamarchuk, Marina; Marinin, Dmitry [Institute of Chemistry FEBRAS, Vladivostok (Russian Federation)

    2017-04-01

    A method of preconcentrating cesium-137 from seawater using a resorcinol-formaldehyde resin, which enables one to optimize the ecological monitoring procedure, has been suggested. Studies of sorption of cesium-137 from seawater by resorcinol-formaldehyde resin have been performed, and it has been demonstrated that the cation exchanger is characterized by high selectivity with respect to cesium-137. It was found that the selectivity depended on the temperature of resin solidification and the seawater pH value. The maximal value of the cesium-137 distribution coefficient is equal to 4.1-4.5 x 10{sup 3} cm{sup 3} g{sup -1}. Under dynamic conditions, the ion-exchange resin capacity is 310-910 bed volumes depending on the seawater pH, whereas the efficiency of cesium removal exceeds 95%. The removal of more than 95% of cesium-137 has been attained using 1-3 M solutions of nitric acid: here, the eluate volume was 8-8.4 bed volumes. Application of 3 M solution of nitric acid results in resin degradation with the release of gaseous products.

  16. An activated microporous carbon prepared from phenol-melamine-formaldehyde resin for lithium ion battery anode

    International Nuclear Information System (INIS)

    Zhu, Yinhai; Xiang, Xiaoxia; Liu, Enhui; Wu, Yuhu; Xie, Hui; Wu, Zhilian; Tian, Yingying

    2012-01-01

    Highlights: ► Microporous carbon was prepared by chemical activation of phenol-melamine-formaldehyde resin. ► Activation leads to high surface area, well-developed micropores. ► Micropores lead to strong intercalation between carbon and lithium ion. ► Large surface area promotes to improve the lithium storage capacity. -- Abstract: Microporous carbon anode materials were prepared from phenol-melamine-formaldehyde resin by ZnCl 2 and KOH activation. The physicochemical properties of the obtained carbon materials were characterized by scanning electron microscope, X-ray diffraction, Brunauer–Emmett–Teller, and elemental analysis. The electrochemical properties of the microporous carbon as anode materials in lithium ion secondary batteries were evaluated. At a current density of 100 mA g −1 , the carbon without activation shows a first discharge capacity of 515 mAh g −1 . After activation, the capacity improved obviously. The first discharge capacity of the carbon prepared by ZnCl 2 and KOH activation was 1010 and 2085 mAh g −1 , respectively. The reversible capacity of the carbon prepared by KOH activation was still as high as 717 mAh g −1 after 20 cycles, which was much better than that activated by ZnCl 2 . These results demonstrated that it may be a promising candidate as an anode material for lithium ion secondary batteries.

  17. Economic, human and environmental health benefits of replacing formaldehyde in the preservation of corpses.

    Science.gov (United States)

    Rocha Ferreira, Jussara; Cardoso Rezende, Lorenna; Barbosa, Abel De Souza; De Carvalho, Phellip; De Lima, Natácia Evangelista; Assis Carvalho, Alexandre

    2017-11-01

    Formaldehyde has been prominent in preserving biological tissues since the nineteenth century. Despite being admittedly harmful to health and to the environment, it is still widely used. The Morphology Department of the University of Brasília - Brazil, applied the rethink, reduce, reuse, recycle and responsibility methodology to their activities in an effort to protect the health of laboratory workers and users, save resources and reduce damage to the environment. Here we evaluate the results obtained a decade after the implementation of this proposal (2005-2015). Formaldehyde was replaced by alcohol and glycerol solutions in corpse conservation. Over five thousand dollars in public funds that would have been destined to buying preserving substances were saved annually, and over a hundred thousand liters of water that would have been contaminated and thrown into the sewage system were spared. The environment used to implement the study was improved and anatomical parts kept for study had their lifespan extended. It is noteworthy that such simple adjustments could cause pronounced changes in laboratory activities. We would avoid contaminating billions of liters of water and it would be possible to save millions if similar practices were implemented in all educational institutions having similar routines. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Comparative study of photocatalytic oxidation on the degradation of formaldehyde and fuzzy mathematics evaluation of filters

    Science.gov (United States)

    Yu, Huili; Zhang, Jieting

    2012-04-01

    In this study, formaldehyde, one of the major volatile organic compounds, is chosen as the target pollutant. The polytetrafluoroethylene (PTFE) filter, a low cost and commonly used material in industry, is employed as the substrate for nano TiO2 photocatalyst coating at room temperature, which has been scarcely used compared to ceramics or glass beads. Furthermore, a specific experimental set-up that is similar to actual air purification system is developed for the testing. The degradation mechanisms of photolysis reaction, adsorption and photocatalytic oxidation reaction on volatile organic compounds are present respectively. The influences of three aspects mentioned above are compared by a serial of experimental data. The high efficiency of volatile organic compounds on the degradation of formaldehyde is assured. Furthermore, the purification characteristics of three kinds of activated carbon filters and PTFE filter with nano TiO2 are evaluated with the method of fuzzy mathematics. In the end, the result shows that the filter with nano TiO2 has the optimal comprehensive performances.

  19. Preparation and Characterization of UV-Curable Cyclohexanone-Formaldehyde Resin and Its Cured Film Properties

    Directory of Open Access Journals (Sweden)

    Guang Yang

    2014-01-01

    Full Text Available UV-curable cyclohexanone-formaldehyde (UVCF resin was prepared with cyclohexanone-formaldehyde (CF resin, isophorone diisocyanate (IPDI, and pentaerythritol triacrylate (PETA as base substance, bridging agent, and functional monomer, respectively. The structure of UVCF was characterized by Fourier transform infrared spectroscopy (FT-IR, 1H-nuclear magnetic resonance spectroscopy (1H-NMR, and gel permeation chromatography (GPC. The viscosity and photopolymerization behavior of the UV-curable formulations were studied. The thermal stability and mechanical properties of the cured films were also investigated. The results showed that UVCF resin was successfully prepared, the number of average molecular weight was about 2010, and its molecular weight distribution index was 2.8. With the increase of UVCF resin content, the viscosity of the UV-curable formulations increased. After exposure to UV irradiation for 230 s, the photopolymerization conversion of the UV-curable formulations was above 80%. Moreover, when the UVCF content was 60%, the formulations had high photopolymerization rate, and the cured UVCF films showed good thermal stability and mechanical properties.

  20. High-resolution inversion of OMI formaldehyde columns over the Southeast US to infer isoprene emissions

    Science.gov (United States)

    Kaiser, J.; Zhu, L.; Travis, K.; Jacob, D.

    2017-12-01

    In the South East United States, biogenic isoprene fuels tropospheric ozone formation, and its oxidation products contribute significantly to organic aerosol. Bottom-up emission inventories rely on very limited isoprene emission and land-cover data, yielding uncertainties of a factor of 2 or more. Here, we use formaldehyde columns from the Ozone Monitoring Instrument in a high-resolution (0.25 x 0.325o) adjoint-based inversion to constrain isoprene emissions over the SE US during Aug-Sept of 2013. We find that the MEGANv2.1 inventory is biased high over most of the SE US. Our derived scaling factors show significant spatial variability, with the largest corrections applied to Louisiana and the Edwards Plateau in Texas. We test our inversion results against a comprehensive set of isoprene oxidation product observations from the NASA SEAC4RS flight campaign. The SEAC4RS data provides new confidence in the satellite retrievals and in mechanism linking isoprene oxidation to formaldehyde production. Finally, we relate the posterior scaling factors to the underlying land-type, and examine potential sources of observed biases.

  1. Amperometric Enzyme-based Gas Sensor for Formaldehyde: Impact of Possible Interferences

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2007-02-01

    Full Text Available In this work, cross-sensitivities and environmental influences on the sensitivityand the functionality of an enzyme-based amperometric sensor system for the directdetection of formaldehyde from the gas phase are studied. The sensor shows a linearresponse curve for formaldehyde in the tested range (0 - 15 vppm with a sensitivity of1.9 μA/ppm and a detection limit of about 130 ppb. Cross-sensitivities by environmentalgases like CO2, CO, NO, H2, and vapors of organic solvents like methanol and ethanol areevaluated as well as temperature and humidity influences on the sensor system. The sensorshowed neither significant signal to CO, H2, methanol or ethanol nor to variations in thehumidity of the test gas. As expected, temperature variations had the biggest influence onthe sensor sensitivity with variations in the sensor signal of up to 10 % of the signal for 5vppm CH2O in the range of 25 - 30 °C.

  2. Synthesis and characterization of resorcinol–formaldehyde resin chars doped by zinc oxide

    International Nuclear Information System (INIS)

    Gun’ko, Vladimir M.; Bogatyrov, Viktor M.; Oranska, Olena I.; Urubkov, Iliya V.; Leboda, Roman; Charmas, Barbara; Skubiszewska-Zięba, Jadwiga

    2014-01-01

    Polycondensation polymerization of resorcinol–formaldehyde (RF) mixtures in water with addition of different amounts of zinc acetate and then carbonization of dried gels are studied to prepare ZnO doped chars. Zinc acetate as a catalyst of resorcinol–formaldehyde polycondensation affects structural features of the RF resin (RFR) and, therefore, the texture of chars prepared from Zn-doped RFR. The ZnO doped chars are characterized using thermogravimetry, low temperature nitrogen adsorption/desorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). At a relatively high content of zinc acetate (1 mol per 10–40 mol of resorcinol) in the reaction mixture, the formation of crystallites of ZnO (zincite) occurs in a shape of straight nanorods of 20–130 nm in diameter and 1–3 μm in length. At a small content of zinc acetate (1 mol per 100–500 mol of resorcinol), ZnO in composites is XRD amorphous and does not form individual particles. The ZnO doped chars are pure nanoporous at a minimal ZnO content and nano-mesoporous or nano-meso-macroporous at a higher ZnO content.

  3. CHARACTERIZATION OF ALKALINE LIGNINS FOR USE IN PHENOL-FORMALDEHYDE AND EPOXY RESINS

    Directory of Open Access Journals (Sweden)

    Nour Eddine El Mansouri

    2011-05-01

    Full Text Available Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignins in thermosetting materials. To evaluate the potential application of lignin raw materials in phenol formaldehyde and epoxy resins, three types of alkaline lignins were characterized in terms of their structures and thermal properties. The lignin samples analyzed were kraft lignin (LIG-1, soda–rice straw lignin (LIG-2, and soda-wheat straw lignin (LIG-3. FTIR and 1H-NMR methods were used to determine their structure. Gel permeation chromatography (GPC was used to determine the molecular weight distribution (MWD. Differential scanning calorimetry (DSC was used to measure the glass transition temperature (Tg, and thermogravimetric analysis (TGA to determine the thermal stability of lignin samples. Results showed that kraft lignin (LIG-1 has moderate hydroxyl-group content, is rich in G-type units, and has good thermal stability. These properties make it more suitable for direct use in phenol formaldehyde resins, and it is therefore a good raw material for this purpose. The alkaline soda-rice straw lignin (LIG-2 with a high hydroxyl-group content and excellent thermal stability is most suited to preparing lignin-based epoxy resins.

  4. Production of bioflocculants prepared from formaldehyde wastewater for the potential removal of arsenic.

    Science.gov (United States)

    Zhao, Haijuan; Zhong, Chunying; Chen, Honggao; Yao, Jie; Tan, Liqing; Zhang, Youlang; Zhou, Jiangang

    2016-05-01

    A novel bioflocculant (MBF-79) prepared using formaldehyde wastewater as carbon resource was investigated in the study. The optimal conditions for bioflocculant production were determined to be an inoculum size of 7.0%, initial pH of 6.0, and formaldehyde concentration of 350 mg/L. An MBF-79 of 8.97 g/L was achieved as the maximum yield. Three main elements, namely C, H, and O, were present in MBF-79 with relative weigh percentages of 39.17%, 6.74%, and 34.55%, respectively. The Gel permeation chromatography analysis indicated that the approximate molecular weight (MW) of MBF-79 was 230 kDa. MBF-79 primarily comprised polysaccharide (71.2%) and protein (27.9%). Additionally, conditions for the removal of arsenic by MBF-79 were found to be MBF-79 at 120 mg/L, an initial pH 7.0, and a contact time 60 min. Under the optimal conditions, the removal efficiencies of arsenate (0.5 mg/L) and arsenite (0.5 mg/L) were 98.9% and 84.6%, respectively. Overall, these findings indicate bioflocculation offers an effective alternative method of decreasing arsenic during water treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Melamine-formaldehyde microcapsules filled sappan dye modified polypropylene composites: encapsulation and thermal properties

    Science.gov (United States)

    Phanyawong, Suphitcha; Siengchin, Suchart; Parameswaranpillai, Jyotishkumar; Asawapirom, Udom; Polpanich, Duangporn

    2018-01-01

    Sappan dye, a natural dye extracted from sappan wood is widely used in cosmetics, textile dyeing and as food additives. However, it was recognized that natural dyes cannot withstand high temperature. In this study, a protective coating of melamine-formaldehyde shell material was applied over the sappan dye to improve its thermal stability. The percentage of sappan dye used in the microencapsulation was 30, 40, 50, 60 and 70 wt%. The color, shape, size, and thermal stability of sappan dye microcapsules were investigated. It was found that increasing amount of sappan dye content in the microcapsules decreased the particle size. Thermal analysis reveals that the melamine-formaldehyde resin served as an efficient protective shell for sappan dye. Besides, 30 wt% sappan dye microcapsules with different weight percent (1, 3 and 5 wt%) of sappan dye was used as modifier for polypropylene (PP). All the prepared composites are red in color which supports the thermal stability of the microcapsules. The changes in crystallinity and melting behavior of PP by the addition of microcapsules were studied in detail by differential scanning calorimetry. Thermogravimetric studies showed that the thermal stability of PP composites increased by the addition of microcapsules.

  6. Nasopharyngeal carcinoma in Malaysian Chinese: occupational exposures to particles, formaldehyde and heat.

    Science.gov (United States)

    Armstrong, R W; Imrey, P B; Lye, M S; Armstrong, M J; Yu, M C; Sani, S

    2000-12-01

    During 1990-1992, 282 Chinese residents of Selangor and the Federal Territory, Malaysia with histologically confirmed nasopharyngeal carcinoma (NPC) were interviewed about occupational history, diet, alcohol consumption, and tobacco use, as were an equal number of Malaysian Chinese population controls, pair-matched to cases by age and sex. Exposures to 20 kinds of workplace substances, solar and industrial heat, and cigarette smoke, were analysed by univariate and multivariate methods. Nasopharyngeal carcinoma was associated with occupational exposures to construction, metal and wood dusts; motor fuel and oil; paints and varnishes; certain other chemicals; industrial heat; solar heat from outdoor occupations; certain smokes; cigarette smoking; and childhood exposure to parental smoking. After adjustment for risk from diet and cigarette smoke, only wood dust (OR = 2.36; 95% CI : 1.33- 4.19), and industrial heat (OR = 2.21; 95% CI : 1.12-4.33) remained clearly associated. Wood dust remained statistically significant after further adjustment for social class. No significant crude or adjusted association was found between NPC and formaldehyde (adjusted OR = 0.71; 95% CI : 0.34-1.43). This study supports previous findings that some occupational inhalants are risk factors for NPC. The statistical effect of wood dust remained substantial after adjustment for diet, cigarette smoke, and social class. Intense industrial heat emerged as a previously unreported risk factor, statistically significant even after adjustment for diet and cigarette smoke. No association was found between NPC and formaldehyde.

  7. Effects of formaldehyde-enriched mists on Pseudotsuga menziesii (Mirbel) Franco and Lobaria pulmonaria (L.) Hoffm.

    Science.gov (United States)

    Muir, P S; Shirazi, A M

    1996-01-01

    The atmosphere in some areas is polluted with formaldehyde (HCHO); however, little is known about effects of HCHO on plants at concentrations resembling those in polluted areas. The effects of simulated fogwater enriched with HCHO on seedlings of Pseudotsuga menziesii (Mirbel) Franco (Douglas fir) and pendants of Lobaria pulmonaria (L.) Hoffm. were assessed. Plants were treated with HCHO-enriched fog (target concentrations of 100, 500, and 1000 microm) during five 4-night mist sessions. Growth and nitrogenase activity (acetylene reduction rate) for lichens and growth and timing of bud-break for Douglas fir were monitored. Nitrogenase activity was lowest in lichens treated at the highest HCHO concentration after all but the first mist session, and it declined significantly with increasing HCHO concentration after the final mist session (R(2) = 0.60, p = 0.02). However, differences in nitrogenase activity among treatments were generally not statistically significant (most p values from ANOVAs were >/= 0.20). Formaldehyde did not affect growth of the lichens. Budbreak of Douglas firs was slightly delayed and height growth was slightly depressed with increasing HCHO concentration, although effects were not statistically significant.

  8. Adsorption of Mefenamic Acid From Water by Bentonite Poly urea formaldehyde Composite Adsorbent

    Directory of Open Access Journals (Sweden)

    Basma Abbas Abdel Majeed

    2017-07-01

    Full Text Available Poly urea formaldehyde –Bentonite (PUF-Bentonite composite was tested as new adsorbent for removal of mefenamic acid (MA from simulated wastewater in batch adsorption procedure. Developed a method for preparing poly urea formaldehyde gel in basic media by using condensation polymerization. Adsorption experiments were carried out as a function of water pH, temperature, contact time, adsorbent dose and initial MA concentration .Effect of sharing surface with other analgesic pharmaceuticals at different pH also studied. The adsorption of MA was found to be strongly dependent to pH. The Freundlich isotherm model showed a good fit to the equilibrium adsorption data. From Dubinin–Radushkevich model the mean free energy (E was calculated and the value of 5 KJ/mole indicated that the main mechanism governing the adsorption of MA on PUF-Bentonite composite was physical in nature. The kinetics of adsorption tested for first order, pseudo second order models and Elovich’s equation, results showed the adsorption followed the pseudo-second-order model

  9. Changes in the nasal epithelium of rats exposed by inhalation to mixtures of formaldehyde, acetaldehyde, and acrolein

    NARCIS (Netherlands)

    Cassee, F.R.; Groten, J.P.; Feron, V.J.

    1996-01-01

    Formaldehyde, acetaldehyde, and acrolein are well-known upper respiratory tract irritants and occur simultaneously as pollutants in many indoor and outdoor environments. The upper respiratory tract, and especially the nose, is the prime target for inhaled aldehydes. To study possible additive or

  10. Control of formaldehyde and TVOC emission from wood-based flooring composites at various manufacturing processes by surface finishing.

    Science.gov (United States)

    Kim, Sumin

    2010-04-15

    This paper assesses the reproducibility of testing formaldehyde and TVOC emission behavior from wood flooring composites bonded by urea-formaldehyde resin at various manufacturing steps for surface finishing materials. The surface adhesion step of laminate flooring for this research was divided into two steps; HDF only and HDF with LPMs. In the case of engineered flooring, the manufacturing steps were divided into three steps; plywood only, fancy veneer bonded on plywood and UV coated on fancy veneer with plywood. Formaldehyde and VOCs emission decreased at the process of final surface finishing materials; LPMs were applied on the surface of HDF for laminate flooring. Although emissions increased when fancy veneer was bonded onto plywood in the case of engineered flooring, emission was dramatically reduced up to similar level with plywood only when final surface finishing; UV-curable coating was applied on fancy veneer. This study suggests that formaldehyde and VOCs emission from floorings can be controlled at manufacturing steps for surface finishing. 2009 Elsevier B.V. All rights reserved.

  11. Immunogenicity of commercial, formaldehyde and binary ethylenimine inactivated Newcastle disease virus vaccines in specific pathogen free chickens

    Directory of Open Access Journals (Sweden)

    Razmaraii, N.

    2012-06-01

    Full Text Available Newcastle disease (ND is one of the most important diseases that affect birds; the epizootic nature of the disease has caused severe economic losses in the poultry industry worldwide. In this experiment ND virus (NDV was inactivated by two different chemicals binary ethylenimine (BEI and formaldehyde. Formaldehyde was used at 0.1%, while BEI was used at concentrations of 1 to 4 mM. NDV inactivation with BEI was done in various incubation temperatures and periods and the best result (30 °C, 4 mM BEI and 21 hrs treatment used as an experimental vaccine. Prepared inactivated NDV vaccines and a commercial vaccine were tested for their efficiency in generating humoral immune response in different groups of specific pathogen free (SPF chicks. Test groups received 0.2 ml formaldehyde inactivated NDV (NDVF, BEI inactivated NDV (NDVEI and Razi institute produced NDV vaccine (NDVR subcutaneously respectively. HI Log 2 total mean titer of NDVEI group (8.42 ± 0.12 were significantly higher than NDVF (7.64 ± 0.16 and NDVR (7.86 ± 0.11 groups (p<0.05. BEI-inactivated vaccine gave higher antibody titers than formaldehyde-inactivated vaccine and preserves both structural integrity and antigenicity of the virus. Thus, it might be possible to use these compounds as an inactivator agent for commercial NDV inactivated vaccines in future.

  12. Preformed amide-containing biopolymer for improving the environmental performance of synthesized urea–formaldehyde in agro-fiber composites

    Science.gov (United States)

    Altaf H. Basta; Houssni El-Saied; Jerrold E. Winandy; Ronald Sabo

    2011-01-01

    Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches. This study examines the role of adding amide-containing biopolymers during synthesis of urea–formaldehyde (UF) on properties of adhesive produced, especially its adhesion potential. The environmental performance of UF-resin synthesized in the...

  13. Reaction of formaldehyde at the ortho- and para-positions of phenol: exploration of mechanisms using computational chemistry.

    Science.gov (United States)

    Anthony H. Conner; Melissa S. Reeves

    2001-01-01

    Computational chemistry methods can be used to explore the theoretical chemistry behind reactive systems, to compare the relative chemical reactivity of different systems, and, by extension, to predict the reactivity of new systems. Ongoing research has focused on the reactivity of a wide variety of phenolic compounds with formaldehyde using semi-empirical and ab...

  14. Sensitivity of Ambient Atmospheric Formaldehyde and Ozone to Precursor Species and Source Types Across the United States

    Science.gov (United States)

    Formaldehyde (HCHO) is an important air pollutant from both an atmospheric chemistry and human health standpoint. This study uses an instrumented photochemical Air Quality Model, CMAQ-DDM, to identify the sensitivity of HCHO concentrations across the United States (U.S.) to major...

  15. The comparison of mechanical and thermal properties of carbon nanotubes and graphene naonosheets enhanced phenol-formaldehyde resin

    International Nuclear Information System (INIS)

    Wu, X.F.; Zhang, Y.; Wu, Y.Z.; Li, Y.J.W.H.

    2017-01-01

    Graphene naonosheets were prepared via one-pot hydrothermal process in a Teflon-lined autoclave. Moreover, the mechanical and thermal degradation behaviors of the phenol formaldehyde/carbon nanotubes and phenol formaldehyde/graphene naonosheets composites were discussed. Experimental results showed that the graphene naonosheets possessed better performances than that of carbon nanotubes. When the filler loading was 0.6wt%, tensile strength, Young's modulus, compressive strength and modulus of the as-prepared composites reached their maximum values, which were increased by 77.0, 141.3, 109.1 and 114.8% for graphene naonosheets and 54.7, 85.9, 61.7 and 45.2% for carbon nanotubes than those of pure sample, respectively. In addition, both of these two carbon materials could increase the thermo-stability of the matrix. When their usage amount was 0.6wt%, the thermal degradation temperature (at 10% weight loss) was increased to 255.6°C for phenol formaldehyde/graphene naonosheets composites and 253.5°C for phenol formaldehyde/carbon nanotubes composites from 233.6°C for pure sample. (author)

  16. 2-[(Hydroxymethyl)amino]ethanol in water as a preservative: Study of formaldehyde released by Taguchi's method

    Science.gov (United States)

    Wisessirikul, W.; Loykulnant, S.; Montha, S.; Fhulua, T.; Prapainainar, P.

    2016-06-01

    This research studied the quantity of free formaldehyde released from 2- [(hydroxymethyl)amino]ethanol (HAE) in DI water and natural rubber latex mixture using high-performance liquid chromatography (HPLC) technique. The quantity of formaldehyde retained in the solution was cross-checked by using titration technique. The investigated factors were the concentration of preservative (HAE), pH, and temperature. Taguchi's method was used to design the experiments. The number of experiments was reduced to 16 experiments from all possible experiments by orthogonal arrays (3 factors and 4 levels in each factor). Minitab program was used as a tool for statistical calculation and for finding the suitable condition for the preservative system. HPLC studies showed that higher temperature and higher concentration of the preservative influence the amount of formaldehyde released. It was found that conditions at which formaldehyde was released in the lowest amount were 1.6%w/v HAE, 4 to 40 °C, and the original pH. Nevertheless, the pH value of NR latex should be more than 10 (the suitable pH value was found to be 13). This preservative can be used to replace current preservative systems and can maintain the quality of latex for long-term storage. Use of the proposed preservative system was also shown to have reduced impact on the toxicity of the environment.

  17. Synthesis of nano-TiO{sub 2}/diatomite composite and its photocatalytic degradation of gaseous formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guangxin; Sun, Zhiming, E-mail: zhimingsun@cumtb.edu.cn; Duan, Yongwei; Ma, Ruixin; Zheng, Shuilin, E-mail: shuilinzheng8@gmail.com

    2017-08-01

    Highlights: • TiO{sub 2}/diatomite composite was synthesized by hydrolysis deposition method. • The composite displayed higher photocatalytic performance for formaldehyde. • The dispersion effect of diatomite was a key factor for high photoactivity. • The composite is a promising photocatalyst for the indoor air purification. - Abstract: The TiO{sub 2}/diatomite composite was synthesized through a mild hydrolysis of titanyl sulfate. The prepared composite was characterized by X-ray diffraction, N{sub 2} adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and UV–vis diffused reflectance spectroscopy. The results demonstrate that the anatase TiO{sub 2} nanopartilces anchored on the surface of diatomite with Ti–O–Si bonds between diatomite and TiO{sub 2}. The photodegradation of gaseous formaldehyde under UV irradiation by the TiO{sub 2}/diatomite composite was studied under various operating conditions, including relative humidity, illumination intensity and catalyst amount, which have significant influence on the degradation process. The TiO{sub 2}/diatomite composite exhibited better photocatalytic activity than pure TiO{sub 2}, which could be attributed to the favorable nanoparticles dispersibility and strong formaldehyde adsorption capacity. In addition, the composite exhibited outstanding reusability over five cycles. The TiO{sub 2}/diatomite composite shows great promising application foreground in formaldehyde degradation.

  18. 40 CFR 86.1320-90 - Gas meter or flow instrumentation calibration; particulate, methanol, and formaldehyde measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Gas meter or flow instrumentation... Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1320-90 Gas meter or flow..., methanol and formaldehyde emissions requires the use of gas meters or flow instrumentation to determine...

  19. Retrieval of global upper tropospheric and stratospheric formaldehyde (H2CO distributions from high-resolution MIPAS-Envisat spectra

    Directory of Open Access Journals (Sweden)

    G. P. Stiller

    2008-02-01

    Full Text Available The Fourier transform spectrometer MIPAS (Michelson Interferometer for Passive Atmospheric Sounding on Envisat measures infrared emission of the Earth's atmosphere in a limb viewing mode. High spectral resolution measurements of MIPAS are sensitive to formaldehyde from the upper troposphere to the stratopause. Single profile retrievals of formaldehyde are dominated by a 60% noise error; however zonal mean values for 30 days of data during 8 September 2003 and 1 December 2003 reduces this error by a factor of 20 or more. The number of degrees of freedom for single profile retrieval ranges from 2 to 4.5 depending on latitude and number of cloud-free tangent altitudes. In the upper tropical troposphere zonal mean values of about 70 parts per trillion by volume (pptv were found, which have been attributed to biomass burning emissions. In the stratosphere, formaldehyde values are determined by photochemical reactions. In the upper tropical stratosphere, formaldehyde zonal mean maximum values can reach 130 pptv. Diurnal variations in this region can be up to 50 pptv. Comparisons with other satellite instruments show generally good agreement in the region of upper troposphere and lower stratosphere as well as in the upper stratosphere.

  20. Catalytic Activity Studies of Vanadia/Silica–Titania Catalysts in SVOC Partial Oxidation to Formaldehyde: Focus on the Catalyst Composition

    Directory of Open Access Journals (Sweden)

    Niina Koivikko

    2018-02-01

    Full Text Available In this work, silica–titania supported catalysts were prepared by a sol–gel method with various compositions. Vanadia was impregnated on SiO2-TiO2 with different loadings, and materials were investigated in the partial oxidation of methanol and methyl mercaptan to formaldehyde. The materials were characterized by using N2 physisorption, X-ray diffraction (XRD, X-ray fluorescence spectroscopy (XRF, X-ray photoelectron spectroscopy (XPS, Scanning transmission electron microscope (STEM, NH3-TPD, and Raman techniques. The activity results show the high importance of an optimized SiO2-TiO2 ratio to reach a high reactant conversion and formaldehyde yield. The characteristics of mixed oxides ensure a better dispersion of the active phase on the support and in this way increase the activity of the catalysts. The addition of vanadium pentoxide on the support lowered the optimal temperature of the reaction significantly. Increasing the vanadia loading from 1.5% to 2.5% did not result in higher formaldehyde concentration. Over the 1.5%V2O5/SiO2 + 30%TiO2 catalyst, the optimal selectivity was reached at 415 °C when the maximum formaldehyde concentration was ~1000 ppm.

  1. Awareness, prevalence of hair smoothing products that contain formaldehyde and determinants of their harmful effects among women in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Yara Nasser Hameed

    2017-10-01

    Full Text Available Individuals who use hair smoothing products at home or in a salon work environment are at risk of exposure to various chemical compounds. Formaldehyde mixed with keratin as a hair straightening product is in common use by women in Saudi Arabia. The high temperatures used during blow-drying can release gas fumes that have several implications to include irritation of the skin, eyes and respiratory complications. Furthermore, formaldehyde is classified as a known human carcinogen. The aim of this study is to assess the source of keratin hair treatment among women, demonstrate the symptoms related to formaldehyde exposure during keratin hair treatment process and determine the practices that can increase the exposure to formaldehyde and to evaluate the level of formaldehyde in the keratin hair treatment products. A national cross-sectional survey was first conducted during March-April 2017 on Saudi Arabian children and women aged between the age of 12 and 50 years old. A standardized, fully confidential questionnaire was provided to participating members. A total of 330 filled questionnaires were obtained within the study location. Moreover, 30 hair salons that used keratin-based products were visited in 3 different cities in Al Qassim province to check the location of keratin hair treatment, ventilation procedures and take samples of hair products that were later analyzed. Most commonly reported symptom was irritation of the eyes reported by 135 people. Other symptoms described include irritation of throat, burning sensation of the nose, headache and nausea. Argan e Ojon was one of the most famous product tested in this study with formaldehyde levels above 0.2% threshold (0.35%. It is worrying thatArgan e Ojon does not comply with GSO 1943 and SASO 1953 standards. A majority of salons demonstrated poor ventilation measures and failed to isolate their clients from the general public and salon workers. With the evident complications, more should be

  2. Reversible and formaldehyde-mediated covalent binding of a bis-amino mitoxantrone analogue to DNA.

    Science.gov (United States)

    Konda, Shyam K; Kelso, Celine; Pumuye, Paul P; Medan, Jelena; Sleebs, Brad E; Cutts, Suzanne M; Phillips, Don R; Collins, J Grant

    2016-05-18

    The ability of a bis-amino mitoxantrone anticancer drug (named WEHI-150) to form covalent adducts with DNA, after activation by formaldehyde, has been studied by electrospray ionisation mass spectrometry and HPLC. Mass spectrometry results showed that WEHI-150 could form covalent adducts with d(ACGCGCGT)2 that contained one, two or three covalent links to the octanucleotide, whereas the control drugs (daunorubicin and the anthracenediones mitoxantrone and pixantrone) only formed adducts with one covalent link to the octanucleotide. HPLC was used to examine the extent of covalent bond formation of WEHI-150 with d(CGCGCG)2 and d(CG(5Me)CGCG)2. Incubation of WEHI-150 with d(CG(5Me)CGCG)2 in the presence of formaldehyde resulted in the formation of significantly greater amounts of covalent adducts than was observed with d(CGCGCG)2. In order to understand the observed increase of covalent adducts with d(CG(5Me)CGCG)2, an NMR study of the reversible interaction of WEHI-150 at both CpG and (5Me)CpG sites was undertaken. Intermolecular NOEs were observed in the NOESY spectra of d(ACGGCCGT)2 with added WEHI-150 that indicated that the drug selectively intercalated at the CpG sites and from the major groove. In particular, NOEs were observed from the WEHI-150 H2,3 protons to the H1' protons of G3 and G7 and from the H6,7 protons to the H5 protons of C2 and C6. By contrast, intermolecular NOEs were observed between the WEHI-150 H2,3 protons to the H2'' proton of the (5Me)C3 in d(CG(5Me)CGCG)2, and between the drug aliphatic protons and the H1' proton of G4. This demonstrated that WEHI-150 preferentially intercalates at (5Me)CpG sites, compared to CpG sequences, and predominantly via the minor groove at the (5Me)CpG site. The results of this study demonstrate that WEHI-150 is likely to form interstrand DNA cross-links, upon activation by formaldehyde, and consequently exhibit greater cytotoxicity than other current anthracenedione drugs.

  3. By-passing acidification limitations during the biofiltration of high formaldehyde loads via the application of ozone pulses

    Energy Technology Data Exchange (ETDEWEB)

    García-Pérez, Teresa [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4a Sección, San Luis Potosí, SLP 78216 (Mexico); Aizpuru, Aitor [Universidad del Mar, Puerto Ángel, Distrito de San Pedro Pochutla, Oaxaca, México C.P. 70902 (Mexico); Arriaga, Sonia, E-mail: sonia@ipicyt.edu.mx [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4a Sección, San Luis Potosí, SLP 78216 (Mexico)

    2013-11-15

    Highlights: • Ozone addition permits to treat higher formaldehyde loads than ever reported. • Ozone addition acts as an indirect in situ pH regulator, minimizing the accumulation of acid byproducts. • Mineralization of formaldehyde occurs, which has never been reported. • Low ozone levels have no negative effects on biological degradation activity. • The use of hybrid processes allows overcoming biofiltration limitations. -- Abstract: A formaldehyde airstream was treated in a biofilter for an extended period of time. During the first 133 days, the reactor was operated without ozone, whereas over the following 82 days ozone was intermittently implemented. The maximum stable elimination capacity obtained without ozone was around 57 g m{sup −3} h{sup −1}. A greater load could not be treated under these conditions, and no significant formaldehyde removal was maintained for inlet loads greater than 65 g m{sup −3} h{sup −1}; the activity of microorganisms was then inhibited by the presence of acidic byproducts, and the media acidified (pH < 4). The implementation of ozone pulses allowed a stable elimination capacity to be obtained, even at greater loads (74 g m{sup −3} h{sup −1}). The effect of ozone on the extra cellular polymeric substances detachment from the biofilm could not be confirmed due to the too low biofilter biomass content. Thus, the results suggest that ozone acted as an in situ pH regulator, preventing acidic byproducts accumulation, and allowing the treatment of high loads of formaldehyde.

  4. Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Taichi [Department of Biology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Department of Dermatology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Takahashi, Akihisa [Department of Biology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Kondo, Natsuko [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Mori, Eiichiro [Department of Biology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Okamoto, Noritomo [Department of Otorhinolaryngology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Nakagawa, Yosuke [Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Ohnishi, Ken [Department of Biology, Ibaraki Prefectual University of Health Sciences, 4669-2 Ami, Ami-mati, Inasiki-gun, Ibaraki 300-0394 (Japan); Zdzienicka, Malgorzata Z. [Department of Molecular Cell Genetics, Collegium Medicum in Bydgoszcz, Nicolaus-Copernicus-University in Torun, ul. Sklodowskiej-Curie 9, 85-094 Bydgoszcz (Poland); Thompson, Larry H. [Biosciences and Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808 (United States); Helleday, Thomas [Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ (United Kingdom); Department of Genetics, Microbiology and Toxicology Stockholm University, SE-106 91 Stockholm (Sweden); Asada, Hideo [Department of Dermatology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); and others

    2011-01-07

    The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA{sup -/-}, FANCC{sup -/-}, FANCA{sup -/-}C{sup -/-}, FANCD2{sup -/-} and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical {gamma}H2AX-staining assay. Although the sensitivity of FANCA{sup -/-}, FANCC{sup -/-} and FANCA{sup -/-}C{sup -/-} cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2{sup -/-} cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, {gamma}H2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex. -- Research highlights: {yields} We examined to clarify the repair pathways of formaldehyde-induced DNA damage. Formaldehyde induces DNA double strand breaks (DSBs). {yields} DSBs are repaired through the Fanconi anemia (FA) repair pathway. {yields} This pathway is independent of the FA nuclear core complex. {yields} We also found that homologous recombination repair was induced by formaldehyde.

  5. Ion Exchange Properties of a Terpolymer Resin Derived from 2, 4-Dihydroxybenzaldehyde, Oxamide and Formaldehyde

    Directory of Open Access Journals (Sweden)

    M. V. Tarase

    2009-01-01

    Full Text Available Terpolymer resins (2,4-DHBOF were synthesized by the condensation of 2,4-dihydroxybenzaldehyde and oxamide with formaldehyde in the presence of hydrochloric acid as catalyst, proved to be selective chelation ion exchange terpolymer resins for certain metals. Chelation ion exchange properties of these polymers were studied for Fe+3, Cu+2, Hg+2, Cd+2, Co+2, Zn+2, Ni+2 and Pb+2 ions. A batch equilibrium method was employed in the study of the selectivity of the distribution of a given metal ions between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in a media of various ionic strengths. The polymer showed a higher selectivity for Fe+3, Cd+2 and Co+2 ions than for Cu+2, Hg+2, Zn+2, Ni+2 and Pb+2 ions.

  6. Photoreduction of carbon dioxide and water into formaldehyde and methanol on semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Aurian-Blajeni, B; Halmann, M; Manassen, J

    1980-01-01

    Heterogeneous photoassisted reduction of aqueous carbon dioxide was achieved using semiconductor powders, with either high-pressure Hg-lamps or sunlight as energy sources. The products were methanol, formaldehyde and methane. The reaction was carried out either as a gas-solid process, by passing carbon dioxide and water vapor over illuminated semiconductor surfaces, or as a liquid-solid reaction, by illuminating aqueous suspensions of semiconductor powders through which carbon dioxide was bubbled. Best results, under illumination by Hg-lamps, were obtained with aqueous suspensions of strontium titanate, SrTiO3, tungsten oxide, WO3, and titanium oxide, TiO2, resulting in absorbed energy conversion efficiencies of 6, 5.9 and 1.2 per cent, respectively.

  7. Kinetics based reaction optimization of enzyme catalysed reduction of formaldehyde to methanol with synchronous cofactor regeneration

    DEFF Research Database (Denmark)

    Marpani, Fauziah Binti; Sárossy, Zsuzsa; Pinelo, Manuel

    2017-01-01

    regeneration of the reducing equivalents during reaction is required. Herein, we report the optimization of the enzymatic conversion of formaldehyde (CHOH) to CH3 OH by alcohol dehydrogenase, the final step of the enzymatic redox reaction of CO2 to CH3 OH, with kinetically synchronous enzymatic cofactor...... regeneration using either glucose dehydrogenase (System I) or xylose dehydrogenase (System II). A mathematical model of the enzyme kinetics was employed to identify the best reaction set-up for attaining optimal cofactor recycling rate and enzyme utilization efficiency. Targeted process optimization...... experiments were conducted to verify the kinetically modelled results. Repetitive reaction cycles were shown to enhance the yield of CH3 OH, increase the total turnover number (TTN) and the biocatalytic productivity rate (BPR) value for both system I and II whilst minimizing the exposure of the enzymes...

  8. High-Throughput Platform for Synthesis of Melamine-Formaldehyde Microcapsules.

    Science.gov (United States)

    Çakir, Seda; Bauters, Erwin; Rivero, Guadalupe; Parasote, Tom; Paul, Johan; Du Prez, Filip E

    2017-07-10

    The synthesis of microcapsules via in situ polymerization is a labor-intensive and time-consuming process, where many composition and process factors affect the microcapsule formation and its morphology. Herein, we report a novel combinatorial technique for the preparation of melamine-formaldehyde microcapsules, using a custom-made and automated high-throughput platform (HTP). After performing validation experiments for ensuring the accuracy and reproducibility of the novel platform, a design of experiment study was performed. The influence of different encapsulation parameters was investigated, such as the effect of the surfactant, surfactant type, surfactant concentration and core/shell ratio. As a result, this HTP-platform is suitable to be used for the synthesis of different types of microcapsules in an automated and controlled way, allowing the screening of different reaction parameters in a shorter time compared to the manual synthetic techniques.

  9. Safety Profile of TiO2-Based Photocatalytic Nanofabrics for Indoor Formaldehyde Degradation

    Directory of Open Access Journals (Sweden)

    Guixin Cui

    2015-11-01

    Full Text Available Anatase TiO2 nanoparticles (TNPs are synthesized using the sol-gel method and loaded onto the surface of polyester-cotton (65/35 fabrics. The nanofabrics degrade formaldehyde at an efficiency of 77% in eight hours with visible light irradiation or 97% with UV light. The loaded TNPs display very little release from nanofabrics (~0.0% during a standard fastness to rubbing test. Assuming TNPs may fall off nanofabrics during their life cycles, we also examine the possible toxicity of TNPs to human cells. We found that up to a concentration of 220 μg/mL, they do not affect viability of human acute monocytic leukemia cell line THP-1 macrophages and human liver and kidney cells.

  10. Ketahanan Bending Komposit Hybrid Serat Batang Kelapa/Serat Gelas Dengan Matrik Urea Formaldehyde

    Directory of Open Access Journals (Sweden)

    Nasmi Herlina Sari

    2012-11-01

    Full Text Available The composite has its own advantages compared to other alternative techniques such material is strong, lightweight,corrosion-resistant, economical and so on. The purpose of this study was to investigate the characteristics of bending strengthfiber composite hybrid coconut trunk / fiber glass using urea formaldehyde resin.Hybrid palm trunk fiber /glass fiber composite have been made by hand lay up which volume fraction fiber hybridvariation namely 10:20, 15:15 and 20:10 (% with length fiber 2 cm. Every Tests conducted were bending testing with eachvariation performed three times repetition. Bending test specimens in accordance with standard ASTMD 790.The results of bending strength of palm trunk fiber hybrid composite / fiber-glass with random fiber direction that thehighest bending strength in the palm trunk fiber volume fraction 10% and 20% glass fiber that is 22.7 N/mm2.

  11. Passion fruit hulls particleboard: the effect of urea formaldehyde level on physical and mechanical properties

    Science.gov (United States)

    Iswanto, A. H.; Sucipto, T.; Adlina, E.; Prabuningrum, D. S.

    2018-02-01

    The purpose of this research was to explore the suitability of Passion Fruit Hulls (PFH) as a raw material particleboard with variants of urea formaldehyde adhesive content (UF). In this research, PFH particles filtered by sieve in size of 10 mesh to throw dust particles. Furthermore, the particles dried until reaches of 5% moisture content. Levels of UF adhesive was using comprise of 10%, 12% and 14%. Hot pressing conducted at 120°C temperature for 10 minutes at a pressure of 30 kg/cm2. The results showed that in moisture content for 10% adhesive level, almost all the parameters such as thickness swelling, modulus of elasticity (MOE) and modulus of rupture (MOR) that produced did not fulfiled the standard. The 14% adhesive level produced of the best of PFH particleboard.

  12. A review of regulatory risk assessment with formaldehyde as an example.

    Science.gov (United States)

    Imbus, H R

    1988-09-01

    Quantitative risk assessment may vary by over a millionfold depending upon the model used. The EPA currently uses models which project the highest potential risk. Furthermore, there is no consideration of the probability that a chemical is a human carcinogen. Such an approach may result in unrealistically high risk at exposures far below current ambient levels. In the case of formaldehyde, three alternative approaches to risk assessment are examined. One uses the maximum likelihood estimate of the multistage model, another uses the no observable adverse effect level divided by a safety factor of 100, and the third uses a probability estimate that the substance is carcinogenic at typical ambient exposures multiplied by EPA's upper bound estimate. The probability estimate is made from considerations of metabolism and pharmacokinetics, toxicology, short-term tests, animal tests, and epidemiology.

  13. Determination of trace amount of formaldehyde base on a bromate-Malachite Green system.

    Science.gov (United States)

    Tang, Yufang; Chen, Hao; Weng, Chao; Tang, Xiaohui; Zhang, Miaoling; Hu, Tao

    2015-01-25

    A novel catalytic kinetic spectrophotometric method for determination of trace amount of formaldehyde (FA) has been established, based on catalytic effect of trace amount of FA on the oxidation of Malachite Green (MG) by potassium bromate in presence of sulfuric acid medium, and was reported for the first time. The method was monitored by measuring the decrease in absorbance of MG at 617 nm and allowed a precise determination of FA in the range of 0.003-0.08 μg mL(-1), with a limit of detection down to 1 ng mL(-1). The relative standard deviation of 10 replicate measurements was 1.63%. The method developed was approved to be sensitive, selective and accurate, and adopted to determinate free FA in samples directly with good accuracy and reproducibility. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Cesium Isotherm Testing with Spherical Resorcinol-Formaldehyde Resin at High Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smoot, Margaret R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rinehart, Donald E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-04-01

    Washington River Protection Solutions (WRPS) is developing a Low-Activity Waste Pretreatment System (LAWPS) to provide low-activity waste (LAW) directly to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste Facility for immobilization. The pretreatment that will be conducted on tank waste supernate at the LAWPS facility entails filtration to remove entrained solids and cesium (Cs) ion exchange to remove Cs from the product sent to the WTP. Currently, spherical resorcinol-formaldehyde (sRF) resin (Microbeads AS, Skedsmokorset, Norway) is the Cs ion exchange resin of choice. Most work on Cs ion exchange efficacy in Hanford tank waste has been conducted at nominally 5 M sodium (Na). WRPS is examining the possibility of processing supernatant at high Na concentrations—up to 8 M Na—to maximize processing efficiency through the LAWPS. Minimal Cs ion exchange work has been conducted at 6 M and 8 M Na concentrations..

  15. Preparation, Characterization, and Properties of In Situ Formed Graphene Oxide/Phenol Formaldehyde Nanocomposites

    Directory of Open Access Journals (Sweden)

    Weihua Xu

    2013-01-01

    Full Text Available Graphene oxide (GO has shown great potential to be used as fillers to develop polymer nanocomposites for important applications due to their special 2D geometrical structure as well as their outstanding mechanical, thermal, and electrical properties. In this work, GO was incorporated into phenol formaldehyde (PF resin by in situ polymerization. The morphologies and structures of GO sheets were characterized by FTIR, XRD, and AFM methods. The structure and properties of the GO/PF nanocomposites were characterized using FTIR, XRD, DSC, and TGA methods. Effects of GO content, reactive conditions, and blending methods on the structure and properties of GO/PF nanocomposites were studied. It was found that due to the well dispersion of GO sheets in polymer matrix and the strong interfacial interaction between the GO sheets and PF matrix, the thermal stability and thermal mechanical properties of the GO/PF nanocomposites were greatly enhanced.

  16. Using cellulose nanofiber as filler of urea formaldehyde resin in plywood manufacture

    Directory of Open Access Journals (Sweden)

    samira barzali

    2015-11-01

    Full Text Available Abstract In this study, physical and mechanical properties of poplar (Populus nigra plywood made by urea-formaldehyde resin along with nano fiber cellulose were studied. For this reason, the nanofiber cellulose as filler at five levels 0, 1, 3, 5 and 7% based on oven dry weight of resin were used. Physical and mechanical properties of the samples, including water absorption and thickness swelling after 2 and 24 hours immersion in water, bending strength and modulus of elasticity (parallel and perpendicular to surface grain and bonding shear strength were measured. The results showed that increasing the amount of nano fiber cellulose improved the dimentional stability of the boards. Also increasing the amount of nano fiber cellulose increases the bending strength and modulus of elasticity parallel to surface grain. On the other hand, increasing the amount of nano fiber cellulose increases the bonding shear strength but no significant differences observed between the different treatments.

  17. The silver catalyst process for converting methanol to formaldehyde - kinetic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Panzer, E.; Emig, G. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Technische Chemie 1

    1998-12-31

    In pre-experiments a tubular reactor was checked whether it is suitable for kinetic measurement on the system of the silver-catalysed partial oxidation of methanol to formaldehyde. Detrimental effects of heat-transfer and mass-transfer on the experimental results were ruled out. Investigations on the characteristics of the reaction showed that it is possible to manipulate the composition of the product mixture by changing the inlet concentration of the reactants. A modified power-law model was established to describe the reaction kinetics. It considers the preadsorption step of oxygen on the catalysts surface and fits the experimental data quite well. During the rapid oxidation the catalysts surface undergoes a drastic change. It gets coarse and has an adsorption capacity of 11 m{sup 2}/g after being exposed to the reaction mixture. (orig.)

  18. Formaldehyde measurements by Proton transfer reaction – Mass Spectrometry (PTR-MS: correction for humidity effects

    Directory of Open Access Journals (Sweden)

    A. Vlasenko

    2010-08-01

    Full Text Available Formaldehyde measurements can provide useful information about photochemical activity in ambient air, given that HCHO is formed via numerous oxidation processes. Proton transfer reaction mass spectrometry (PTR-MS is an online technique that allows measurement of VOCs at the sub-ppbv level with good time resolution. PTR-MS quantification of HCHO is hampered by the humidity dependence of the instrument sensitivity, with higher humidity leading to loss of PTR-MS signal. In this study we present an analytical, first principles approach to correct the PTR-MS HCHO signal according to the concentration of water vapor in sampled air. The results of the correction are validated by comparison of the PTR-MS results to those from a Hantzsch fluorescence monitor which does not have the same humidity dependence. Results are presented for an intercomparison made during a field campaign in rural Ontario at Environment Canada's Centre for Atmospheric Research Experiments.

  19. An experimental and theoretical investigation into positron and electron scattering from formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Zecca, A; Trainotti, E; Chiari, L [Department of Physics, University of Trento, Povo, I-38123 Trento (Italy); GarcIa, G [Instituto de Matematicas y Fisica Fundamental, CSIC, Serrano 121, 28006 Madrid (Spain); Blanco, F [Facultad de Ciencias Fisicas, Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense, Avda. Complutense s/n, E-28040 Madrid (Spain); Bettega, M H F [Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, 81531-990 Curitiba, Parana (Brazil); Varella, M T do N [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo, SP (Brazil); Lima, M A P [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, Caixa Postal 6165, 13083-970 Campinas, Sao Paulo (Brazil); Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Brunger, M J, E-mail: Michael.Brunger@flinders.edu.au [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)

    2011-10-14

    We report on measurements of total cross sections (TCSs) for positron scattering from the fundamental organic molecule formaldehyde (CH{sub 2}O). The energy range of these measurements was 0.26-50.3 eV, whereas the energy resolution was {approx}260 meV. To assist us in interpreting these data, Schwinger multichannel level calculations for positron elastic scattering from CH{sub 2}O were also undertaken (0.5-50 eV). These calculations, incorporating an accurate model for the target polarization, are found to be in good qualitative agreement with our measured data. In addition, in order to compare the behaviour of positron and electron scattering from this species, independent atom model-screened additivity rule theoretical electron TCSs, now for energies in the range 1-10 000 eV, are also reported.

  20. A turn-on fluorescent probe for endogenous formaldehyde in the endoplasmic reticulum of living cells

    Science.gov (United States)

    Tang, Yonghe; Ma, Yanyan; Xu, An; Xu, Gaoping; Lin, Weiying

    2017-06-01

    As the simplest aldehyde compounds, formaldehyde (FA) is implicated in nervous system diseases and cancer. Endoplasmic reticulum is an organelle that plays important functions in living cells. Accordingly, the development of efficient methods for FA detection in the endoplasmic reticulum (ER) is of great biomedical importance. In this work, we developed the first ER-targeted fluorescent FA probe Na-FA-ER. The detection is based on the condensation reaction of the hydrazine group and FA to suppress the photo-induced electron transfer (PET) pathway, resulting in a fluorescence increase. The novel Na-FA-ER showed high sensitivity to FA. In addition, the Na-FA-ER enabled the bio-imaging of exogenous and endogenous FA in living HeLa cells. Most significantly, the new Na-FA-ER was employed to visualize the endogenous FA in the ER in living cells for the first time.

  1. Quantum chemistry and dynamics of the abstraction reaction of H atoms from formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Siaï, A. [Faculté des Sciences de Tunis, Département de Physique, (LPMC), Université de Tunis El Manar, 2092 Tunis (Tunisia); Oueslati, I. [Faculté des Sciences de Tunis, Département de Physique, (LPMC), Université de Tunis El Manar, 2092 Tunis (Tunisia); Observatoire de Paris-Meudon, Sorbonne Universités, UPMC Univ Paris 06, UMR8112 du CNRS, LERMA, 5 Place Jules Janssen, 92195 Meudon cedex (France); Académie Militaire, Fondouk Jedid, 8012 Nabeul (Tunisia); Kerkeni, Boutheïna, E-mail: Boutheina.kerkeni@obspm.fr [Faculté des Sciences de Tunis, Département de Physique, (LPMC), Université de Tunis El Manar, 2092 Tunis (Tunisia); Observatoire de Paris-Meudon, Sorbonne Universités, UPMC Univ Paris 06, UMR8112 du CNRS, LERMA, 5 Place Jules Janssen, 92195 Meudon cedex (France); Institut Supérieur des Arts Multimédia de la Manouba, Université de la Manouba, 2010 la Manouba (Tunisia)

    2016-08-02

    This work reports a reduced dimensionality rate constant calculation of the H-abstraction reaction from formaldehyde. Quantum scattering calculations are performed treating explicitly the bonds being broken and formed. Geometry optimisations and frequency calculations are done at the MP2/cc-pVTZ level while energies are calculated with the CCSD(T) method. An analytical potential energy surface was developed from a relatively small number of grid points. When compared to semi-classical approaches, the quantum scattering calculations show that quantum tunnelling yields large contributions at low temperatures. At 200 K, we note a difference of about 5 orders of magnitude between transition state theory (TST) and quantum rate constants. Our predicted results show that the quantum and the CVT/SCT rate constants are in reasonable agreement with the available experiment at high temperatures, but that the last one gives better agreement to experimental results at low temperatures.

  2. ExoMol line lists - VIII. A variationally computed line list for hot formaldehyde

    Science.gov (United States)

    Al-Refaie, Ahmed F.; Yachmenev, Andrey; Tennyson, Jonathan; Yurchenko, Sergei N.

    2015-04-01

    A computed line list for formaldehyde, H212C16O, applicable to temperatures up to T = 1500 K is presented. An empirical potential energy and ab initio dipole moment surfaces are used as the input to the nuclear motion program TROVE. The resulting line list, referred to as AYTY, contains 10.3 million rotational-vibrational states and around 10 billion transition frequencies. Each transition includes associated Einstein-A coefficients and absolute transition intensities, for wavenumbers below 10 000 cm-1 and rotational excitations up to J = 70. Room-temperature spectra are compared with laboratory measurements and data currently available in the HITRAN data base. These spectra show excellent agreement with experimental spectra and highlight the gaps and limitations of the HITRAN data. The full line list is available from the CDS data base as well as at www.exomol.com.

  3. Decontamination of spent ion-exchangers contaminated with cesium radionuclides using resorcinol-formaldehyde resins.

    Science.gov (United States)

    Palamarchuk, Marina; Egorin, Andrey; Tokar, Eduard; Tutov, Mikhail; Marinin, Dmitry; Avramenko, Valentin

    2017-01-05

    The origin of the emergence of radioactive contamination not removable in the process of acid-base regeneration of ion-exchange resins used in treatment of technological media and liquid radioactive waste streams has been determined. It has been shown that a majority of cesium radionuclides not removable by regeneration are bound to inorganic deposits on the surface and inside the ion-exchange resin beads. The nature of the above inorganic inclusions has been investigated by means of the methods of electron microscopy, IR spectrometry and X-ray diffraction. The method of decontamination of spent ion-exchange resins and zeolites contaminated with cesium radionuclides employing selective resorcinol-formaldehyde resins has been suggested. Good prospects of such an approach in deep decontamination of spent ion exchangers have been demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Evaluations of Mechanisms for Pu Uptake and Retention within Spherical Resorcinol-Formaldehyde Resin Columns

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, Calvin H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-15

    The unexpected uptake and retention of plutonium (Pu) onto columns containing spherical resorcinol-formaldehyde (sRF) resin during ion exchange testing of Cs (Cs) removal from alkaline tank waste was observed in experiments at both the Pacific Northwest National Laboratory (PNNL) and the Savannah River National Laboratory (SRNL). These observations have raised concern regarding the criticality safety of the Cs removal unit operation within the low-activity waste pretreatment system (LAWPS). Accordingly, studies have been initiated at Washington River Protection Solutions (WRPS), who manages the operations of the Hanford Site tank farms, including the LAWPS, PNNL, and elsewhere to investigate these findings. As part of these efforts, PNNL has prepared the present report to summarize the laboratory testing observations, evaluate these phenomena in light of published and unpublished technical information, and outline future laboratory testing, as deemed appropriate based on the literature studies, with the goal to elucidate the mechanisms for the observed Pu uptake and retention.

  5. Effect of varying levels of formaldehyde treatment of mustard oil cake on rumen fermentation, digestibility in wheat straw based total mixed diets in vitro

    OpenAIRE

    Mahima,; Kumar, Vinod; Tomar, S. K.; Roy, Debashis; Kumar, Muneendra

    2015-01-01

    Aim: The aim of the current study was to protect the protein in mustard cake by different levels of formaldehyde treatment with a view to optimize the level of formaldehyde. Materials and Methods: Different levels of formaldehyde treatment (0, 1, 1.5 and 2% of crude protein) containing concentrate and roughages diet in 40:60 ratio were tested for their effect on nutrients digestibility, in vitro ammonia release, in vitro gas production and change in protein fractions. Non-significant (p≤0....

  6. Synthesis and structural features of resorcinol–formaldehyde resin chars containing nickel nanoparticles

    International Nuclear Information System (INIS)

    Galaburda, M.V.; Bogatyrov, V.M.; Skubiszewska-Zięba, J.; Oranska, O.I.; Sternik, D.; Gun’ko, V.M.

    2016-01-01

    Graphical abstract: - Highlights: • Facile synthesis of the Ni-doped carbon sorbents via carbonization of resorcinol–formaldehyde polymers/nickel(II) acetate mixtures in the inert atmosphere. • Effects of Ni content, as well as water volume and temperature treatment on the morphology and texture of the chars. • Ni/C composites are characterized by a core–shell structure with well-crystallized graphitic shells. • Ni content influences the structure of the carbon. • Nickel-doped carbon nanocomposites were used as a magnetically separable adsorbent. - Abstract: A series of meso- and microporous carbons containing magnetic Ni nanoparticles (Ni/C) with a variety of Ni loadings were synthesized by a simple one-pot procedure through carbonization of resorcinol–formaldehyde polymers containing various amounts of nickel(II) acetate. Such composite materials were characterized by N_2 sorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscope (TEM). The XRD patterns reveal peaks corresponding to face centered cubic nickel with the average size of crystallites of 17–18 nm. SEM and TEM results reveal that the formation of the nanoparticles took place mainly in the carbon spheres (1–2 μm in size) and on the outer surface as well. The as-prepared composites are characterized by a core–shell structure with well-crystallized graphitic shells about 8–15 nm in thickness. The Raman spectra show that Ni content influences the structure of the carbon. It was also shown that the morphology (particle shape and sizes) and porosity (pore volume and pore size distribution) of the chars are strongly dependent on water and nickel contents in the blends. One of the applications of Ni/C was demonstrated as a magnetically separable adsorbent.

  7. Formaldehyde-induced histone H3 phosphorylation via JNK and the expression of proto-oncogenes

    International Nuclear Information System (INIS)

    Yoshida, Ikuma; Ibuki, Yuko

    2014-01-01

    Graphical abstract: - Highlights: • Formaldehyde modified histones. • The phosphorylation of H3S10 was increased at the promoter regions of proto-oncogenes. • The phosphorylation of H2AXS139 was attributed to FA-induced DNA damage. • The FA-induced initiation and promotion of cancer could be judged by these modifications. - Abstract: Formaldehyde (FA) is a very reactive compound that forms DNA adducts and DNA-protein crosslinks, which are known to contribute to FA-induced mutations and carcinogenesis. Post-translational modifications to histones have recently attracted attention due to their link with cancer. In the present study, we examined histone modifications following a treatment with FA. FA significantly phosphorylated histone H3 at serine 10 (H3S10), and at serine 28 (H3S28), the time-course of which was similar to the phosphorylation of H2AX at serine 139 (γ-H2AX), a marker of DNA double strand breaks. The temporal deacetylation of H3 was observed due to the reaction of FA with the lysine residues of histones. The phosphorylation mechanism was then analyzed by focusing on H3S10. The nuclear distribution of the phosphorylation of H3S10 and γ-H2AX did not overlap, and the phosphorylation of H3S10 could not be suppressed with an inhibitor of ATM/ATR, suggesting that the phosphorylation of H3S10 was independent of the DNA damage response. ERK and JNK in the MAPK pathways were phosphorylated by the treatment with FA, in which the JNK pathway was the main target for phosphorylation. The phosphorylation of H3S10 increased at the promoter regions of c-fos and c-jun, indicating a relationship between FA-induced tumor promotion activity and phosphorylation of H3S10. These results suggested that FA both initiates and promotes cancer, as judged by an analysis of histone modifications

  8. Formaldehyde-induced histone H3 phosphorylation via JNK and the expression of proto-oncogenes

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Ikuma; Ibuki, Yuko, E-mail: ibuki@u-shizuoka-ken.ac.jp

    2014-12-15

    Graphical abstract: - Highlights: • Formaldehyde modified histones. • The phosphorylation of H3S10 was increased at the promoter regions of proto-oncogenes. • The phosphorylation of H2AXS139 was attributed to FA-induced DNA damage. • The FA-induced initiation and promotion of cancer could be judged by these modifications. - Abstract: Formaldehyde (FA) is a very reactive compound that forms DNA adducts and DNA-protein crosslinks, which are known to contribute to FA-induced mutations and carcinogenesis. Post-translational modifications to histones have recently attracted attention due to their link with cancer. In the present study, we examined histone modifications following a treatment with FA. FA significantly phosphorylated histone H3 at serine 10 (H3S10), and at serine 28 (H3S28), the time-course of which was similar to the phosphorylation of H2AX at serine 139 (γ-H2AX), a marker of DNA double strand breaks. The temporal deacetylation of H3 was observed due to the reaction of FA with the lysine residues of histones. The phosphorylation mechanism was then analyzed by focusing on H3S10. The nuclear distribution of the phosphorylation of H3S10 and γ-H2AX did not overlap, and the phosphorylation of H3S10 could not be suppressed with an inhibitor of ATM/ATR, suggesting that the phosphorylation of H3S10 was independent of the DNA damage response. ERK and JNK in the MAPK pathways were phosphorylated by the treatment with FA, in which the JNK pathway was the main target for phosphorylation. The phosphorylation of H3S10 increased at the promoter regions of c-fos and c-jun, indicating a relationship between FA-induced tumor promotion activity and phosphorylation of H3S10. These results suggested that FA both initiates and promotes cancer, as judged by an analysis of histone modifications.

  9. TRANSCRIPTOMIC ANALYSIS OF F344 RAT NASAL EPITHELIUM SUGGESTS THAT THE LACK OF CARCINOGENIC RESPONSE TO GLUTARALDEHYDE IS DUE TO ITS GREATER TOXICITY COMPARED TO FORMALDEHYDE

    Science.gov (United States)

    Formaldehyde is cytotoxic and carcinogenic to the rat nasal respiratory epithelium inducing tumors after 12 months. Glutaraldehyde is also cytotoxic but is not carcinogenic to nasal epithelium even after 24 months. Both aldehydes induce similar acute and subchronic histopathology...

  10. Dataset of Atmospheric Environment Publication in 2016, Source emission and model evaluation of formaldehyde from composite and solid wood furniture in a full-scale chamber

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data presented in this data file is a product of a journal publication. The dataset contains formaldehyde air concentrations in the emission test chamber and...

  11. Assessment of lipid peroxidation and p53 as a biomarker of carcinogenesis among workers exposed to formaldehyde in the cosmetic industry.

    Science.gov (United States)

    Attia, Dalia; Mansour, Neveen; Taha, Fatma; Seif El Dein, Aisha

    2016-06-01

    Despite the wide use of cosmetic products, they exert a number of health effects on tissues ranging from irritation to cancer. Our study aimed at assessing the effect of formaldehyde on lipid peroxidation and verifying the susceptibility to carcinogenesis using p53 as a biomarker among workers exposed to formaldehyde in cosmetic industry. Our entire exposed group (n = 40) and the controls (n = 20) were subjected to estimation of formate in urine, serum malondialdehyde (MDA), and p53. Also, complete blood picture, liver, and kidney function tests were carried out. The study revealed significant increase in the levels of formate, MDA, and p53 in the exposed group compared with their control group. Our results showed that workers in cosmetic industry had significant exposure to formaldehyde. Furthermore, the study pointed to the negative impact of formaldehyde as a cause of oxidative stress and suspicious carcinogen. © The Author(s) 2014.

  12. Effect of Palm Oil Fiber-TiO_2 Ratio in the Composite on the Reduction of BTX and Formaldehyde in the Air

    International Nuclear Information System (INIS)

    Nor Rahafza Abdul Manap; Roslinda Shamsudin; Mohd Norhafsam Maghpor; Muhammad Azmi Abdul Hamid; Azman Jalar

    2016-01-01

    The effect of palm oil fiber-TiO_2 ratio in the composite on the reduction of benzene, toluene, xylene and formaldehyde in the air is studied. The ratio was set at 1:0, 1:9 and 5:5. The combination of adsorption process by palm oil fiber and photooxidation of volatile organic compounds by titanium dioxide was revealed. The composite were prepared by using mechanical milling technique. The performance of the composite was characterized in terms of percentage of recovery of benzene, toluene and xylene (BTX) using GC/ FID and formaldehyde concentration reduction using formaldehyde meter. The results of recovery of the BTX by palm oil fiber/ titanium dioxide composite were more than 90 %. The palm oil fiber/ titanium dioxide composite has successfully reduced the concentration of formaldehyde by up to 66.7 %. Therefore, the palm oil mesocarp fiber/ titanium dioxide composite produced is able to reduce the concentration of volatile organic compounds. (author)

  13. [Attempt to reduce the formaldehyde concentration by blowing cooled fresh air down in to the breathing zone of medical students from an admission port on the ceiling during gross anatomy class].

    Science.gov (United States)

    Takayanagi, Masaaki; Sakai, Makoto; Ishikawa, Youichi; Murakami, Kunio; Kimura, Akihiko; Kakuta, Sachiko; Sato, Fumi

    2008-09-01

    Cadavers in gross anatomy laboratories at most medical schools are conventionally embalmed in formaldehyde solution, which is carcinogenic to humans. Medical students and instructors are thus exposed to formaldehyde vapors emitted from cadavers during dissection. To reduce high formaldehyde concentrations in the breathing zone above cadavers being examined by anatomy medical students provisionally, dissection beds were located under existing admission ports on the ceiling to supply cooled fresh air from the admission port blowing downward on to the cadaver. In all cases, compared to normal condition, the downward flow of cooled fresh air from an admission port reduced formaldehyde concentrations by 0.09-0.98 ppm and reduced to 12.6-65.4% in the air above a cadaver in the breathing zone of students. The formaldehyde concentrations above cadavers under admission ports were not more than the formaldehyde concentrations between beds representing the indoor formaldehyde concentrations. Although the application of an existing admission port on the ceiling in this study did not remove formaldehyde, the downflow of cooled fresh air using this system reduced the formaldehyde concentration in the air above cadavers being attended by anatomy students during dissections. These results suggest the need for reducing formaldehyde levels in gross anatomy laboratories using fundamental countermeasures in order to satisfy the guidelines of 0.08 ppm established by the World Health Organization and the Japan Ministry of Health, Labor and Welfare.

  14. Environment-friendly adhesives for surface bonding of wood-based flooring using natural tannin to reduce formaldehyde and TVOC emission.

    Science.gov (United States)

    Kim, Sumin

    2009-01-01

    The objective of this research was to develop environment-friendly adhesives for face fancy veneer bonding of engineered flooring using the natural tannin form bark in the wood. The natural wattle tannin adhesive were used to replace UF resin in the formaldehyde-based resin system in order to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. PVAc was added to the natural tannin adhesive to increase viscosity of tannin adhesive for surface bonding. For tannin/PVAc hybrid adhesives, 5%, 10%, 20% and 30% of PVAc to the natural tannin adhesives were added. tannin/PVAc hybrid adhesives showed better bonding than the commercial natural tannin adhesive with a higher level of wood penetration. The initial adhesion strength was sufficient to be maintained within the optimum initial tack range. The standard formaldehyde emission test (desiccator method), field and laboratory emission cell (FLEC) and VOC analyzer were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with commercial the natural tannin adhesive and tannin/PVAc hybrid adhesives. By desiccator method and FLEC, the formaldehyde emission level of each adhesive showed the similar tendency. All adhesives satisfied the E(1) grade (below 1.5 mg/L) and E(0) grade (below 0.5 mg/L) with UV coating. VOC emission results by FLEC and VOC analyzer were different with the formaldehyde emission results. TVOC emission was slightly increased as adding PVAc.

  15. Measurement of Endogenous versus Exogenous Formaldehyde-Induced DNA-Protein Crosslinks in Animal Tissues by Stable Isotope Labeling and Ultrasensitive Mass Spectrometry.

    Science.gov (United States)

    Lai, Yongquan; Yu, Rui; Hartwell, Hadley J; Moeller, Benjamin C; Bodnar, Wanda M; Swenberg, James A

    2016-05-01

    DNA-protein crosslinks (DPC) arise from a wide range of endogenous and exogenous chemicals, such as chemotherapeutic drugs and formaldehyde. Importantly, recent identification of aldehydes as endogenous genotoxins in Fanconi anemia has provided new insight into disease causation. Because of their bulky nature, DPCs pose severe threats to genome stability, but previous methods to measure formaldehyde-induced DPCs were incapable of discriminating between endogenous and exogenous sources of chemical. In this study, we developed methods that provide accurate and distinct measurements of both exogenous and endogenous DPCs in a structurally specific manner. We exposed experimental animals to stable isotope-labeled formaldehyde ([(13)CD2]-formaldehyde) by inhalation and performed ultrasensitive mass spectrometry to measure endogenous (unlabeled) and exogenous ((13)CD2-labeled) DPCs. We found that exogenous DPCs readily accumulated in nasal respiratory tissues but were absent in tissues distant to the site of contact. This observation, together with the finding that endogenous formaldehyde-induced DPCs were present in all tissues examined, suggests that endogenous DPCs may be responsible for increased risks of bone marrow toxicity and leukemia. Furthermore, the slow rate of DPC repair provided evidence for the persistence of DPCs. In conclusion, our method for measuring endogenous and exogenous DPCs presents a new perspective for the potential health risks inflicted by endogenous formaldehyde and may inform improved disease prevention and treatment strategies. Cancer Res; 76(9); 2652-61. ©2016 AACR. ©2016 American Association for Cancer Research.

  16. Effect of varying levels of formaldehyde treatment of mustard oil cake on rumen fermentation, digestibility in wheat straw based total mixed diets in vitro

    Science.gov (United States)

    Mahima; Kumar, Vinod; Tomar, S. K.; Roy, Debashis; Kumar, Muneendra

    2015-01-01

    Aim: The aim of the current study was to protect the protein in mustard cake by different levels of formaldehyde treatment with a view to optimize the level of formaldehyde. Materials and Methods: Different levels of formaldehyde treatment (0, 1, 1.5 and 2% of crude protein) containing concentrate and roughages diet in 40:60 ratio were tested for their effect on nutrients digestibility, in vitro ammonia release, in vitro gas production and change in protein fractions. Non-significant (p≤0.05) effect on pH, microbial biomass, partitioning factor, total gas production (TGP), TGP per g dry matter and TGP per g digestible dry matter (ml/g) was observed in almost all the treatments. Results: Total volatile fatty acids at 2% formaldehyde treatment level of mustard cake was lower (p<0.05) as compared to other groups, while in vitro dry matter digestibility and in vitro organic matter digestibility were reported to be low in 1% formaldehyde treated group. Conclusion: On a holistic view, it could be considered that formaldehyde treatment at 1.5% level was optimal for protection of mustard oil cake protein. PMID:27047133

  17. Effect of varying levels of formaldehyde treatment of mustard oil cake on rumen fermentation, digestibility in wheat straw based total mixed diets in vitro

    Directory of Open Access Journals (Sweden)

    Mahima

    2015-04-01

    Full Text Available Aim: The aim of the current study was to protect the protein in mustard cake by different levels of formaldehyde treatment with a view to optimize the level of formaldehyde. Materials and Methods: Different levels of formaldehyde treatment (0, 1, 1.5 and 2% of crude protein containing concentrate and roughages diet in 40:60 ratio were tested for their effect on nutrients digestibility, in vitro ammonia release, in vitro gas production and change in protein fractions. Non-significant (p≤0.05 effect on pH, microbial biomass, partitioning factor, total gas production (TGP, TGP per g dry matter and TGP per g digestible dry matter (ml/g was observed in almost all the treatments. Results: Total volatile fatty acids at 2% formaldehyde treatment level of mustard cake was lower (p<0.05 as compared to other groups, while in vitro dry matter digestibility and in vitro organic matter digestibility were reported to be low in 1% formaldehyde treated group. Conclusion: On a holistic view, it could be considered that formaldehyde treatment at 1.5% level was optimal for protection of mustard oil cake protein.

  18. Effect of the polymerization with formaldehyde on the thermal reactivity of a low-temperature coal tar pitch

    Energy Technology Data Exchange (ETDEWEB)

    Jose L. Crespo; Ana Arenillas; Jose A. Vin; Roberto Garcia; Colin E. Snape; Sabino R. Moinelo [Instituto Nacional del Carbon (CSIC), Oviedo (Spain)

    2005-04-01

    The influence of polymerization with formaldehyde on the thermal reactivity of a low-temperature coal tar pitch has been investigated. The mechanism and extent of the polymerization depends on the catalyst used, the greatest extent of polymerization being achieved under basic catalytic conditions. After the polymerization treatment, samples were carbonized at 420{sup o}C and the products were characterized by optical microscopy. According to the results, polymerization with formaldehyde increases the reactivity of the pitch, giving rise to increased carbonization yields and leading to the formation of the mesophase with milder conditions. The polymerization process also affects the morphology of the resultant anisotropic material, giving rise to the formation of irregularly shaped mesophase particles and reducing the optical texture size of the anisotropic domains, giving mosaic texture, especially when basic catalysis is used. 36 refs., 11 figs., 5 tabs.

  19. Simultaneous measurements of formaldehyde and nitrous acid in dews and gas phase in the atmosphere of Santiago, Chile

    Science.gov (United States)

    Rubio, María A.; Lissi, Eduardo; Villena, Guillermo; Elshorbany, Y. F.; Kleffmann, Jörg; Kurtenbach, Ralf; Wiesen, Peter

    2009-12-01

    The amounts of formaldehyde and nitrous acid (HONO) in gas phase and dews of Santiago de Chile were simultaneously measured. Formaldehyde concentrations values in the liquid phase (dews) correlate fairly well with those in the gaseous phase and are even higher than those expected from gas-dew equilibrium. On the other hand, nitrite concentrations in dews were considerably smaller (ca. 15 times) than those expected from the gas-phase concentrations. This under-saturation is attributed to diffusion limitations due to the relatively large HONO solubility. In agreement with this, under-saturation increases with the rate of dew formation and the pH of the collected waters, factors that should increase the rate of gas to liquid HONO transfer required to reach equilibrium.

  20. Evolution of mechanical properties and final textural properties of resorcinol-formaldehyde xerogels during ambient air drying

    OpenAIRE

    Léonard, Angélique; Blacher, Silvia; Crine, Michel; Jomaa, Wahbi

    2008-01-01

    Porous carbon xerogels can be obtained by convective drying of resorcinol (R)-formaldehyde (F) hydrogels, followed by pyrolysis. Drying conditions have to be carefully controlled when crack-free monoliths with well-defined shape and size are required. The knowledge of the mechanical properties of the RF xerogels and their evolution with water content is essential to model their thermo-hygro-mechanical behavior during convective drying and avoid mechanical stresses leading to deformation and c...

  1. THEORETICAL STUDY OF THE REMOVAL OF THE TROPOSPHERIC FORMALDEHYDE BY REACTION WITH OH* AND NH3* RADICALS

    OpenAIRE

    Cjuno H., Jesús A.; Arroyo C., Juan; Cubas C., Roger

    2014-01-01

    In the context of atmospheric chemistry, two reactions radical-molecule of hydrogen abstraction have been studied. These are the OH' and NO3: radical (oxidizers agents in the troposphere) with formaldehyde in gas-phase. The calculations were carried out using the PM3 and . Ab initio methods of the UHF type. The results have allowed us to estimate the corresponding times of tropospheric permanency and the implications of these reactions in the removal of forrnaldehyde and similars from the low...

  2. Optical chemical sensors for atmospheric pollutants based on nano porous materials: application to the formaldehyde and the other carbonyl compounds

    International Nuclear Information System (INIS)

    Paolacci, H.

    2006-12-01

    Formaldehyde, a well-identified indoor pollutant, was recently classified as carcinogenic. New regulations for the air quality are expected and therefore there is a need for low-cost sensors, sensitive and selective with a fast response time for the detection of formaldehyde at ppb level. In the present work, we had developed a chemical sensor based on nano-porous matrices doped with Fluoral-P and optical methods of detection. The nano-porous matrices, elaborated via the Sol-Gel process, display nano-pores whose cavity is tailored for the trapping of the targeted pollutant. They provide a first selectivity with the discrimination of the pollutants by their size. A second selectivity is obtained with a molecular probe, Fluoral-P, which reacts specifically with formaldehyde leading to the 3,5- di-acetyl-1,4-dihydro-lutidine (DDL). The kinetics of formation of DDL was studied as function of many parameters such as the concentration of Fluoral-P in the matrix, the pollutant content in gas mixture, the flow rate, the relative humidity of the gas mixtures and interference with other carbonylated compounds. The present chemical sensor can detect, via absorbance measurements, 2 ppb of formaldehyde within 30 min over a O to 60% relative humidity range. Moreover, to detect the total carbonylated compounds, we also explored the potentiality of a chemical sensor using, as a probe molecule, the 2'4-dinitro-phenyl-hydrazine which forms with these compounds the corresponding hydrazones derivatives. A patent was deposited for these two sensors. We have also developed a semi-miniaturized prototype for demonstration, using a flow cell, a miniaturized spectrophotometer, a light source and a lap-top. (author)

  3. Exposure to low doses of formaldehyde during pregnancy suppresses the development of allergic lung inflammation in offspring

    International Nuclear Information System (INIS)

    Maiellaro, Marília; Correa-Costa, Matheus; Vitoretti, Luana Beatriz; Gimenes Júnior, João Antônio; Câmara, Niels Olsen Saraiva; Tavares-de-Lima, Wothan; Farsky, Sandra Helena Poliselli; Lino-dos-Santos-Franco, Adriana

    2014-01-01

    Formaldehyde (FA) is an environmental and occupational pollutant, and its toxic effects on the immune system have been shown. Nevertheless, no data are available regarding the programming mechanisms after FA exposure and its repercussions for the immune systems of offspring. In this study, our objective was to investigate the effects of low-dose exposure of FA on pregnant rats and its repercussion for the development of allergic lung inflammation in offspring. Pregnant Wistar rats were assigned in 3 groups: P (rats exposed to FA (0.75 ppm, 1 h/day, 5 days/week, for 21 days)), C (rats exposed to vehicle of FA (distillated water)) and B (rats non-manipulated). After 30 days of age, the offspring was sensitised with ovalbumin (OVA)-alum and challenged with aerosolized OVA (1%, 15 min, 3 days). After 24 h the OVA challenge the parameters were evaluated. Our data showed that low-dose exposure to FA during pregnancy induced low birth weight and suppressed the development of allergic lung inflammation and tracheal hyperresponsiveness in offspring by mechanisms mediated by reduced anaphylactic antibodies synthesis, IL-6 and TNF-alpha secretion. Elevated levels of IL-10 were found. Any systemic alteration was detected in the exposed pregnant rats, although oxidative stress in the uterine environment was evident at the moment of the delivery based on elevated COX-1 expression and reduced cNOS and SOD-2 in the uterus. Therefore, we show the putative programming mechanisms induced by FA on the immune system for the first time and the mechanisms involved may be related to oxidative stress in the foetal microenvironment. - Highlights: • Formaldehyde exposure does not cause lung inflammation in pregnant rats. • Formaldehyde exposure suppresses allergic lung inflammation in the offspring. • Formaldehyde exposure induces oxidative stress in uterine environment

  4. 40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

    Science.gov (United States)

    2010-07-01

    ... values should conform to the following statistical precision: Variance = 0.005 Standard deviation = 0.07... example levels: Expected percent free formaldehyde Sample size, grams 2 30.0 5 12.0 8 7.5 10 6.0 12 5.0 15... 30 0.5 60 ii. If the milliliters of titrant are less than 5 mL or greater than 30 mL, reestimate the...

  5. Exposure to low doses of formaldehyde during pregnancy suppresses the development of allergic lung inflammation in offspring

    Energy Technology Data Exchange (ETDEWEB)

    Maiellaro, Marília [Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo (Brazil); Correa-Costa, Matheus [Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo (Brazil); Vitoretti, Luana Beatriz; Gimenes Júnior, João Antônio [Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo (Brazil); Câmara, Niels Olsen Saraiva [Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo (Brazil); Tavares-de-Lima, Wothan [Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo (Brazil); Farsky, Sandra Helena Poliselli [Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo (Brazil); Lino-dos-Santos-Franco, Adriana, E-mail: adrilino@usp.br [Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo (Brazil)

    2014-08-01

    Formaldehyde (FA) is an environmental and occupational pollutant, and its toxic effects on the immune system have been shown. Nevertheless, no data are available regarding the programming mechanisms after FA exposure and its repercussions for the immune systems of offspring. In this study, our objective was to investigate the effects of low-dose exposure of FA on pregnant rats and its repercussion for the development of allergic lung inflammation in offspring. Pregnant Wistar rats were assigned in 3 groups: P (rats exposed to FA (0.75 ppm, 1 h/day, 5 days/week, for 21 days)), C (rats exposed to vehicle of FA (distillated water)) and B (rats non-manipulated). After 30 days of age, the offspring was sensitised with ovalbumin (OVA)-alum and challenged with aerosolized OVA (1%, 15 min, 3 days). After 24 h the OVA challenge the parameters were evaluated. Our data showed that low-dose exposure to FA during pregnancy induced low birth weight and suppressed the development of allergic lung inflammation and tracheal hyperresponsiveness in offspring by mechanisms mediated by reduced anaphylactic antibodies synthesis, IL-6 and TNF-alpha secretion. Elevated levels of IL-10 were found. Any systemic alteration was detected in the exposed pregnant rats, although oxidative stress in the uterine environment was evident at the moment of the delivery based on elevated COX-1 expression and reduced cNOS and SOD-2 in the uterus. Therefore, we show the putative programming mechanisms induced by FA on the immune system for the first time and the mechanisms involved may be related to oxidative stress in the foetal microenvironment. - Highlights: • Formaldehyde exposure does not cause lung inflammation in pregnant rats. • Formaldehyde exposure suppresses allergic lung inflammation in the offspring. • Formaldehyde exposure induces oxidative stress in uterine environment.

  6. Crosslinking studies in gelatin capsules treated with formaldehyde and in capsules exposed to elevated temperature and humidity.

    Science.gov (United States)

    Ofner, C M; Zhang, Y E; Jobeck, V C; Bowman, B J

    2001-01-01

    Incomplete in vitro capsule shell dissolution and subsequent drug release problems have recently received attention. A modified USP dissolution method was used to follow capsule shell dissolution, and a 2,4,6-trinitrobenzenesulfonic acid (TNBS) assay was used to follow loss of epsilon-amino groups to study this shell dissolution problem postulated to be due to gelatin crosslinking. The dissolution problems were simulated using hard gelatin capsule (HGC) shells previously treated with formaldehyde to crosslink the gelatin. These methods were also used to study the effect of uncrosslinked HGC stored under stressed conditions (37 degrees C and 81% RH) with or without the presence of soft gelatin capsule shells (SGC). A 120 ppm formaldehyde treatment reduced gelatin shell dissolution to 8% within 45 min in water at 37 degrees C. A 200 ppm treatment reduced gelatin epsilon-amino groups to 83% of the original uncrosslinked value. The results also support earlier reports of non-amino group crosslinking by formaldehyde in gelatin. Under stressed conditions, HGC stored alone showed little change over 21 weeks. However, by 12 to 14 weeks, the HGC exposed to SGC showed a 23% decrease in shell dissolution and an 8% decrease in the number of epsilon-amino groups. These effects on the stressed HGC are ascribed to a volatile agent from SGC shells, most likely formaldehyde, that crosslinked nearby HGC shells. This report also includes a summary of the literature on agents that reduce gelatin and capsule shell dissolution and the possible mechanisms of this not-so-simple problem. Copyright 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90: 79-88, 2001

  7. Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Søren Thor, E-mail: stl@nrcwe.dk; Wolkoff, Peder, E-mail: pwo@nrcwe.dk; Hammer, Maria, E-mail: mha@nrcwe.dk; Kofoed-Sørensen, Vivi, E-mail: vks@nrcwe.dk; Clausen, Per Axel, E-mail: pac@nrcwe.dk; Nielsen, Gunnar Damgård, E-mail: gdn@nrcwe.dk

    2013-05-01

    We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation.

  8. Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

    International Nuclear Information System (INIS)

    Larsen, Søren Thor; Wolkoff, Peder; Hammer, Maria; Kofoed-Sørensen, Vivi; Clausen, Per Axel; Nielsen, Gunnar Damgård

    2013-01-01

    We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation

  9. Effect of formaldehyde-treated urea on rumen fermentation, ration digestibility and nitrogen utilization

    Directory of Open Access Journals (Sweden)

    Jouko Setälä

    1982-01-01

    Full Text Available The study comprises two experiments in which young Finn-sheep were used as test animals. The experimental rations consisted of equal parts of NaOH-treated wheat (Exp. 1 or barley (Exp. 2 straw and a concentrate mixture of barley-molassed beet pulp (Exp. 1 or barley-oats-molassed beet pulp (Exp.2. Feeding was performed twice a day. In addition 20 grams of urea/animal/day was mixed into the concentrates just before feeding. The urea was treated with the following percentages of formaldehyde, on a weight basis: 0 (F0, 1.0 (F1.0, 3.0(F3.0 and 5.0(F5.0 in Exp. 1 and 0, 1.0 and 1.5(F1.5 in Exp. 2. The digestibility of the total ration decreased, when F3.0 and F5.0 urea was used, but the decrease was significant (P< 0.05 only when the apparent digestibility of crude protein was compared between the F0 and F5.0 diets. The amount of rumen bacteria was decreased (P< 0.05 and the amount of protozoa increased (P< 0.01 by formaldehyde treatment levels above F1.0 and F3.0, respectively. The concentration of the total VFA in the rumen tended to decrease with treatment levels higher than F3.0. No significant differences were found in the composition of the VFA. When treated urea was used, the excretion of nitrogen in the faeces increased but its excretion in the urine decreased. The percentage retention of the nitrogen ingested by the animals on diets F0, F1.0, F3.0, and F5.0 in Exp. 1 was 15.0, 10.8, 13.2 and 12.2 and on diets F0, F1.0 and F1.5 in Exp. 2 it was 20.5, 20.2 and 21.2, respectively.

  10. Kinetic temperature of massive star forming molecular clumps measured with formaldehyde

    Science.gov (United States)

    Tang, X. D.; Henkel, C.; Menten, K. M.; Zheng, X. W.; Esimbek, J.; Zhou, J. J.; Yeh, C. C.; König, C.; Yuan, Y.; He, Y. X.; Li, D. L.

    2017-02-01

    Context. For a general understanding of the physics involved in the star formation process, measurements of physical parameters such as temperature and density are indispensable. The chemical and physical properties of dense clumps of molecular clouds are strongly affected by the kinetic temperature. Therefore, this parameter is essential for a better understanding of the interstellar medium. Formaldehyde, a molecule which traces the entire dense molecular gas, appears to be the most reliable tracer to directly measure the gas kinetic temperature. Aims: We aim to determine the kinetic temperature with spectral lines from formaldehyde and to compare the results with those obtained from ammonia lines for a large number of massive clumps. Methods: Three 218 GHz transitions (JKAKC = 303-202, 322-221, and 321-220) of para-H2CO were observed with the 15 m James Clerk Maxwell Telescope (JCMT) toward 30 massive clumps of the Galactic disk at various stages of high-mass star formation. Using the RADEX non-LTE model, we derive the gas kinetic temperature modeling the measured para-H2CO 322-221/303-202 and 321-220/303-202 ratios. Results: The gas kinetic temperatures derived from the para-H2CO (321-220/303-202) line ratios range from 30 to 61 K with an average of 46 ± 9 K. A comparison of kinetic temperature derived from para-H2CO, NH3, and the dust emission indicates that in many cases para-H2CO traces a similar kinetic temperature to the NH3 (2, 2)/(1, 1) transitions and the dust associated with the HII regions. Distinctly higher temperatures are probed by para-H2CO in the clumps associated with outflows/shocks. Kinetic temperatures obtained from para-H2CO trace turbulence to a higher degree than NH3 (2, 2)/(1, 1) in the massive clumps. The non-thermal velocity dispersions of para-H2CO lines are positively correlated with the gas kinetic temperature. The massive clumps are significantly influenced by supersonic non-thermal motions. The reduced spectra (FITS files) are only

  11. Source emission and model evaluation of formaldehyde from composite and solid wood furniture in a full-scale chamber

    Science.gov (United States)

    Liu, Xiaoyu; Mason, Mark A.; Guo, Zhishi; Krebs, Kenneth A.; Roache, Nancy F.

    2015-12-01

    This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber at different ventilation rates for up to 4000 h using ASTM D 6670-01 (2007). Tests were performed on four types of furniture constructed of different materials and from different manufacturers. The data were used to evaluate two empirical emission models, i.e., a first-order and power-law decay model. The experimental results showed that some furniture tested in this study, made only of solid wood and with less surface area, had low formaldehyde source emissions. The effect of ventilation rate on formaldehyde emissions was also examined. Model simulation results indicated that the power-law decay model showed better agreement than the first-order decay model for the data collected from the tests, especially for long-term emissions. This research was limited to a laboratory study with only four types of furniture products tested. It was not intended to comprehensively test or compare the large number of furniture products available in the market place. Therefore, care should be taken when applying the test results to real-world scenarios. Also, it was beyond the scope of this study to link the emissions to human exposure and potential health risks.

  12. Performance of composite boards from long strand oil palm trunk bonded by isocyanate and urea formaldehyde adhesives

    Science.gov (United States)

    Hermanto, Indra; Massijaya, M. Y.

    2018-03-01

    In this research, the obtained long strand were produced from the outer part of oil palm trunk and then hot-prepressed. The three-ply composite boards were made from hot-prepressed long strand and use bonded by isocyanate and urea formaldehyde adhesives with a glue spread variation of 150 g/m2, 225 g/m2, and 300 g/m2. The board target density was 0.65 g/cm3, face and back layers orientation is the same and the core layer was perpendicular to the face and back layers. The research results showed that : (1) composite boards bonded by isocyanate performed better physical and mechanical properties compared to those of bonded by urea formaldehyde, (2) utilization of higher glue spread level would improve the physical and mechanical properties of the composite board. (3) composite boards bonded by isocyanate and urea formaldehyde adhesives at glue spread of 225 g/m2, 300 g/m2, respectively were enough to fulfill the JIS A 5908 (2003) standard.

  13. [Reducing the levels of formaldehyde exposure during a gross anatomy dissection course with a local ventilation system].

    Science.gov (United States)

    Kikuta, Akio; Yamato, Hiroshi; Kunugita, Naoki; Nakashima, Tamiji; Hayashi, Haruki

    2010-03-01

    Reducing the levels of formaldehyde (FA) exposure in gross anatomy laboratories has been urgently required. We improved the environment of our gross anatomy laboratory by changing the existing general ventilation to local ventilation. We developed a local ventilation apparatus (grid-type of hood with downward suction) that can be attached to an ordinary dissection table. Furthermore, in order to make this local ventilation apparatus an enclosure hood, the upper plate of the dissection table was surrounded by flexible vertical flanges. The apparatus works as an effective enclosure hood without interfering with students' practice of dissection. We installed 26 local ventilation apparatuses and connected them to the ventilation duct. The ventilation ducts were installed above the ceiling or along the pillars not to interfere with students' vision and movements in the room. Adopting the local ventilation system reduced dramatically the students' and lecturers' exposure to formaldehyde. The geometric mean formaldehyde concentration was 0.066 ppm in the anatomy laboratory in 2005. Since 2005, the new system has enabled us to comply with safety and health regulations and providing a smell- and irritant-free dissection room with an excellent environment for anatomy study.

  14. Study on photocatalytic performance of cerium-graphene oxide-titanium dioxide composite film for formaldehyde removal

    International Nuclear Information System (INIS)

    Li, Jia; Zhang, Quan; Lai, Alvin C.K.; Zeng, Liping

    2016-01-01

    In order to degrade in-car formaldehyde gas, graphene oxide (GO), cerium (Ce), and TiO_2 were organically combined by one-step sol-gel method. Then the mixed collosol was coated onto the surface of inorganic glass substrates to form Ce-GO-TiO_2 composite film by way of immersion, coating, and calcinations. The morphology and crystal structure of as-prepared Ce-GO-TiO_2 film were studied by a series of detection techniques. The photocatalytic performance of this film was analyzed by the degradation effect of formaldehyde under simulated sunlight. The results showed that the Ce-GO-TiO_2 film had the inbuilt mesoporous structure in the lamellar stacking with particles. When the doping amount of Ce and GO were 0.4 and 0.2% (mass ratio), the composite film can improve effectively the response to the visible light and its degradation rate for low concentration of formaldehyde was up to 83.8% in simulated sunlight for 7 h, which could be attributed to the co-function of Ce and GO. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. A fate for organic acids, formaldehyde and methanol in cloud water: their biotransformation by micro-organisms

    Directory of Open Access Journals (Sweden)

    P. Amato

    2007-08-01

    Full Text Available The interactions between microbial and chemical contents of cloud water were investigated. First, we observe that the bulk cloud water solution provides a substantial environment where bacteria can develop significantly. Then, a total number of 60 microbial strains originating from seven distinct samples of cloud water and affiliated to various taxonomic groups were examined for their ability to degrade some of the main atmospheric carboxylic compounds: formate, acetate, lactate, succinate, as well as formaldehyde and methanol. Biodegradation tests show that all these compounds can be transformed when used as single carbonaceous substrates, with activities depending on both the strain and the compound. The highest capacities of biodegradation are observed towards formaldehyde, formate and acetate, which are also the more concentrated compounds typically measured in cloud water. Hence, analyses by 1H NMR permitted to establish for instance that compounds like pyruvate or fumarate can be produced and released in the media in relation to the transformation of lactate or succinate. In addition, utilization of 13C labelled formaldehyde showed that it can be transformed through many metabolic pathways, similar to those induced by photochemistry and leading to the production of formate and/or methanol. These results suggest that microorganisms of cloud water can have various behaviours towards the chemical compounds present in the atmosphere: they can represent either a sink or source for organic carbon, and may have to be considered as actors of cloud chemistry.

  16. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    Science.gov (United States)

    Wang, Jinlong; Yunus, Rizwangul; Li, Jinge; Li, Peilin; Zhang, Pengyi; Kim, Jeonghyun

    2015-12-01

    Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnOx) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnOx/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnOx layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO4 and then surface-deposition of MnOx particles from the bulk phase. The MnOx particles assembled with nanosheets were uniformly coated on the PET fibers. MnOx/PET showed good activity for HCHO decomposition at room temperature which followed the Mars-van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m3, space velocity ∼17,000 h-1 and relative humidity∼50%. This research provides a facile method to deposit active MnOx onto polymers with low air resistance, and composite MnOx/PET material is promising for indoor air purification.

  17. B{sub 36} borophene as an electronic sensor for formaldehyde: Quantum chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shahbazi Kootenaei, Amirhossein, E-mail: a.kootenaei@gmail.com [Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr (Iran, Islamic Republic of); Ansari, Goodarz [Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr (Iran, Islamic Republic of)

    2016-08-06

    Pristine carbon nanotubes and graphene show great sensitivity toward several lethal gases but cannot identify some extremely toxic chemicals such as formaldehyde (HCOH). Recent successful synthesis of all-boron graphene-like sheets attracted strong interest in exploring their possible applications. Herein, we inspected the potential application of B{sub 36} borophene sheet as a sensor for HCOH detection, using density functional theory computations. Different theoretical levels including B97D and Minnesota 06 functionals with different basis sets were employed. It was predicted that the electrical conductivity of B{sub 36} borophene significantly increases at the presence of HCOH molecules, thereby generating an electrical signal. The electrical signal is increased by increasing the number of adsorbed HCOH molecules, indicating that this sensor is sensitive to the concentration (or pressure) of HCOH gas. These results suggest that the pristine borophene may be used in the HCOH chemical sensors. - Highlights: • B{sub 36} borophene sheet can be used as a chemical sensor for HCOH detection. • The B{sub 36} is sensitive to the concentration of HCOH. • When the B{sub 36} adsorbs HCOH molecules, it is converted to a p-type semiconductor.

  18. Adenovirus type 5 DNA-protein complexes from formaldehyde cross-linked cells early after infection

    International Nuclear Information System (INIS)

    Spector, David J.; Johnson, Jeffrey S.; Baird, Nicholas L.; Engel, Daniel A.

    2003-01-01

    We report here the properties of viral DNA-protein complexes that purify with cellular chromatin following formaldehyde cross-linking of intact cells early after infection. The cross-linked viral DNA fractionated into shear-sensitive (S) and shear- resistant (R) components that were separable by sedimentation, which allowed independent characterization. The R component had the density and sedimentation properties expected for DNA-protein complexes and contained intact viral DNA. It accounted for about 50% of the viral DNA recovered at 1.5 h after infection but less than 20% by 4.5 h. The proportion of R component was independent of multiplicity of infection, even at less than one particle per cell. Viral hexon and protein VII, but not protein VI, were detected in the fractions containing the R component. These properties are consistent with those of partially uncoated virions associated with the nuclear envelope. A substantial proportion of the S component viral DNA had the same density as cellular chromatin. Protein VII was the most abundant viral protein present in gradient fractions that contained the S component. Complexes containing USF transcription factor cross-linked to the adenovirus major late promoter were detected by viral chromatin immunoprecipitation of the fractions containing S component. The S component probably contained uncoated nuclear viral DNA that assembles into early viral transcription complexes

  19. Molecular analysis of formaldehyde-induced mutations in human lymphoblasts and E. coli

    International Nuclear Information System (INIS)

    Crosby, R.M.; Richardson, K.K.; Craft, T.R.; Benforado, K.B.; Liber, H.L.; Skopek, T.R.

    1988-01-01

    The molecular nature of formaldehyde (HCHO)-induced mutations was studied in both human lymphoblasts and E. coli. Thirty HPRT - human lymphoblast colonies induced by eight repetitive 150 μM HCHO treatments were characterized by Southern blot analysis. Fourteen of these mutants (47%) had visible deletions of some or all of the X-linked HPRT bands, indicating that HCHO can induce large losses of DNA in human lymphoblasts. In E. coli., DNA alterations induced by HCHO were characterized with use of the xanthine guanine phosphoribosyl transferase (gpt) gene as the genetic target. Exposure of E. coli to 4 mM HCHO for 1 hr induced large insertions (41%), large deletions (18%), and point mutations (41%). Dideoxy DNA sequencing revealed that most of the point mutations were transversions at GC base pairs. In contrast, exposure of E. coli to 40 mM HCHO for 1 hr produced 92% point mutations, 62% of which were transitions at a single AT base pair in the gene. Therefore, HCHO is capable of producing different genetic alterations in E. coli at different concentrations, suggesting fundamental differences in the mutagenic mechanisms operating at the two concentrations used. Naked pSV2gpt plasmid DNA was exposed to 3.3 or 10 mM HCHO and transformed into E. coli. Most of the resulting mutations were frameshifts, again suggesting a different mutagenic mechanism

  20. Fire Safety Tests for Spherical Resorcinol Formaldehyde Resin: Data Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Sang; Peterson, Reid A.; Schweiger, Michael J.

    2012-07-30

    A draft safety evaluation of the scenario for spherical resorcinol-formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping, which may be overly bounding based on the fire performance data from the manufacturer of the ion exchange resin selected for use at the WTP. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI), following the American Society for Testing and Materials (ASTM) standard procedures, through a subcontract managed by Pacific Northwest National Laboratory (PNNL). For some tests, the ASTM standard procedures were not entirely appropriate or practical for the SRF resin material, so the procedures were modified and deviations from the ASTM standard procedures were noted. This report summarizes the results of fire safety tests performed and reported by SwRI. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. All as-received SwRI reports are attached to this report in the Appendix. Where applicable, the precision and bias of each test method, as given by each ASTM standard procedure, are included and compared with the SwRI test results of the SRF resin.

  1. Synthesis and Characterization of Bio-Oil Phenol Formaldehyde Resin Used to Fabricate Phenolic Based Materials.

    Science.gov (United States)

    Cui, Yong; Hou, Xiaopeng; Wang, Wenliang; Chang, Jianmin

    2017-06-18

    In this study, bio-oil from the fast pyrolysis of renewable biomass was used as the raw material to synthesize bio-oil phenol formaldehyde (BPF) resin-a desirable resin for fabricating phenolic-based material. During the synthesis process, paraformaldehyde was used to achieve the requirement of high solid content and low viscosity. The properties of BPF resins were tested. Results indicated that BPF resin with the bio-oil addition of 20% had good performance on oxygen index and bending strength, indicating that adding bio-oil could modify the fire resistance and brittleness of PF resin. The thermal curing behavior and heat resistance of BPF resins were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Results showed that adding bio-oil had an impact on curing characteristics and thermal degradation process of PF resin, but the influence was insignificant when the addition was relatively low. The chemical structure and surface characteristics of BPF resins were determined by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The analysis demonstrated that adding bio-oil in the amount of 20% was able to improve the crosslinking degree and form more hydrocarbon chains in PF resin.

  2. Enhanced thermal properties with graphene oxide in the urea-formaldehyde microcapsules containing paraffin PCMs.

    Science.gov (United States)

    Qiao, Zhen; Mao, Jian

    2017-02-01

    In this study, compact urea-formaldehyde microcapsules containing paraffin (UFP) phase change materials (PCMs) were prepared via in situ polymerisation. The thermal conductivity of the PCMs was enhanced without influencing their enthalpy by adding graphene oxide (GO). Two modification methods were investigated: One in which GO is added to the inside of microcapsules, defined as "paraffin/GO@UF composite"; and another in which GO is coated onto the surface of shell, defined as "paraffin@UF/GO composite". The GO sheets were visible in scanning electron microscope (SEM) images of paraffin@UF/GO composite. The thermal conductivity was 0.2236 ± 0.0003 W/(m·K) for UFP particles, was 0.2517 ± 0.0003 W/(m·K) for the paraffin/GO@UF composite (10 wt%), and was 1.0670 ± 0.0020 W/(m·K) for paraffin@UF/GO composite (10 wt%), respectively. The encapsulation efficiency of all samples exceeded 80% (w/w) and all samples exhibited favourable thermal stability and reliability. The IR emissivity of paraffin@UF/GO was lower than that of paraffin/GO@UF when the same GO amount was added to the composite.

  3. Thermoanalytical Study and Kinetics of New 8-Hydroxyquinoline 5-sulphonic Acid-Oxamide-Formaldehyde Terpolymer Resins

    Directory of Open Access Journals (Sweden)

    Rajesh N. Singru

    2009-01-01

    Full Text Available The terpolymer resins (8-HQ5-SAOF have been synthesized by the condensation of 8-hydroxyquinoline 5-sulphonic acid (8-HQ5-SA and oxamide (O with formaldehyde (F in the presence of acid catalyst and using varied molar proportion of the reacting monomers. The synthesized terpolymer resins have been characterized by different physico-chemical techniques. Thermogravimetric analysis of all terpolymer resins in present study have been carried out by non-isothermal thermogravimetric analysis technique in which sample is subjected to condition of continuous increase in temperature at linear rate. Thermal study of the resins was carried out to determine their mode of decomposition and relative thermal stabilities. Thermal decomposition curves were studied carefully with minute details. The Freeman-Carroll and Sharp-Wentworth methods have been used in the present investigation to calculate thermal activation energy and different kinetic parameter of the terpolymer resins. Thermal activation energy (Ea calculated with above two mentioned methods are in close agreement. The advantage of Freeman-Carroll method is to calculate both the order of reaction (n and energy of activation in one single stage by keeping heating rate constant. By using data of thermogravimetric analysis, various thermodynamic parameters like frequency factor (Z, entropy change (Δ S, free energy change (Δ F and apparent entropy (S* have been determined using Freeman-Carroll method.

  4. Chemical derivatization to enhance chemical/oxidative stability of resorcinol-formaldehyde resin

    Energy Technology Data Exchange (ETDEWEB)

    Hubler, T.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    The goal of this task is to develop modified resorcinol-formaldehyde (R-F) resin to improve the chemical/oxidative stability of the resin. R-F resin is a regenerable organic ion-exchange resin that is selective for cesium ion in highly alkaline, high ionic-strength solutions. R-F resin tends to undergo chemical degradation, reducing its ability to remove cesium ion from waste solutions; the mechanistic details of these decomposition reactions are currently unknown. The approach used for this task is chemical modification of the resin structure, particularly the resorcinol ring unit of the polymer resin. This approach is based on prior characterization studies conducted at Pacific Northwest National Laboratory (PNNL) that indicated the facile chemical degradation of the resin is oxidation of the resorcinol ring to the para-quinone structure, with subsequent loss of ion-exchange sites for cesium ion. R-F resin represents an important alternative to current radiocesium remediation technology for tank wastes at both the Hanford and Savannah River sites, particularly if regenerable resins are needed.

  5. Evidence for Conversion of Methanol to Formaldehyde in Nonhuman Primate Brain.

    Science.gov (United States)

    Zhai, Rongwei; Zheng, Na; Rizak, Joshua; Hu, Xintian

    2016-01-01

    Many studies have reported that methanol toxicity to primates is mainly associated with its metabolites, formaldehyde (FA) and formic acid. While methanol metabolism and toxicology have been best studied in peripheral organs, little study has focused on the brain and no study has reported experimental evidence that demonstrates transformation of methanol into FA in the primate brain. In this study, three rhesus macaques were given a single intracerebroventricular injection of methanol to investigate whether a metabolic process of methanol to FA occurs in nonhuman primate brain. Levels of FA in cerebrospinal fluid (CSF) were then assessed at different time points. A significant increase of FA levels was found at the 18th hour following a methanol injection. Moreover, the FA level returned to a normal physiological level at the 30th hour after the injection. These findings provide direct evidence that methanol is oxidized to FA in nonhuman primate brain and that a portion of the FA generated is released out of the brain cells. This study suggests that FA is produced from methanol metabolic processes in the nonhuman primate brain and that FA may play a significant role in methanol neurotoxicology.

  6. Functional toxicogenomic profiling expands insight into modulators of formaldehyde toxicity in yeast

    Directory of Open Access Journals (Sweden)

    Matthew North

    2016-11-01

    Full Text Available Formaldehyde (FA is a commercially important chemical with numerous and diverse uses. Accordingly, occupational and environmental exposure to FA is prevalent worldwide. Various adverse effects, including nasopharyngeal, sinonasal, and lymphohematopoietic cancers, have been linked to FA exposure, prompting designation of FA as a human carcinogen by U.S. and international scientific entities. Although the mechanism(s of FA toxicity have been well studied, additional insight is needed in regard to the genetic requirements for FA tolerance. In this study, a functional toxicogenomics approach was utilized in the model eukaryotic yeast Saccharomyces cerevisiae to identify genes and cellular processes modulating the cellular toxicity of FA. Our results demonstrate mutant strains deficient in multiple DNA repair pathways–including homologous recombination, single strand annealing, and postreplication repair–were sensitive to FA, indicating FA may cause various forms of DNA damage in yeast. The SKI complex and its associated factors, which regulate mRNA degradation by the exosome, were also required for FA tolerance, suggesting FA may have unappreciated effects on RNA stability. Furthermore, various strains involved in osmoregulation and stress response were sensitive to FA. Together, our results are generally consistent with FA-mediated damage to both DNA and RNA. Considering DNA repair and RNA degradation pathways are evolutionarily conserved from yeast to humans, mechanisms of FA toxicity identified in yeast may be relevant to human disease and genetic susceptibility.

  7. Assessing the Levels and Health Risk of Atmospheric Formaldehyde in Makkah, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Atef M.F. Mohammed

    2015-07-01

    Full Text Available Atmospheric Formaldehyde (HCHO was monitored in four sites on the Holy Mosque of Makkah, Saudi Arabia during August, 2013. The daily mean concentrations of HCHO were ranged from 1.09-18.92 g/m3. The levels of HCHO were significantly higher than the permissible exposure limit (0.042 μg/m3 of the Occupational Safety and Health Administration (OSHA. However, it were not exceeded the recommended exposure limit of the National Institute for Occupational Safety and Health (20 μg/m3 and Egyptian law 4/1994 (0.37 mg/m3. Spatial variations of HCHO concentrations most probably due to variations in local meteorology and traffic flow, which was considered the main source of emissions. Exposure doses for various age groups were estimated, which ranged from 0.000004 to 0.000259 mg/kg/day. Maximum exposure dose was recorded for boys (age 12-14 years and children (6-8 years and minimum for females (19-65 years.

  8. Genetic effects of formaldehyde in yeast. Current status and limitations of the radiation equivalence concept

    International Nuclear Information System (INIS)

    Chanet, R.; Magana-Schwencke, N.; Moustacchi, E.

    1980-01-01

    Values of radiation equivalents of chemicals have been calculated for formaldehyde (FA) from detailed data on its genetic effects on yeast, Saccharomyces cerevisiae, and compared with the effects induced by gamma radiation. For the haploid yeast strain, 1 (mmol FA.ltr -1 ).min (i.e. 1 mM FA.min) is equivalent to 9.6 rad, and for diploid yeast it is equivalent to 33 rad. These values are within the range of values calculated for E. coli and mammalian cells. Some major differences in the response to FA and radiation are encountered, depending upon the cellular physiological conditions, the genetic background and the degree of ploidy (haploid versus diploid) and growth phase (exponential versus stationary), among others. Difficulties encountered in the estimation of rad-equivalent values for specific chemicals and for defined biological end-points (e.g. rate of reverse mutation in the specific biochemical loci) are discussed. It is concluded that by exercising appropriate caution relating to the differences in the mechanisms of action of the chemical mutagens and radiations, meaningful rad-equivalent values could be estimated that could help express the comparative biological effects of chemicals in terms of radiation unit. (author)

  9. Synthesis and structural characteristics of polycyclic aromatic hydrocarbon-containing phenol formaldehyde resites

    Energy Technology Data Exchange (ETDEWEB)

    Sirkecioglu, O.; Andresen, J.M.; McRae, C.; Snape, C.E. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

    1997-10-24

    Nonsoftening phenol-formaldehyde (PF) co-resites can be used to probe the formation of polycyclic aromatic hydrocarbons (PAHs) during the carbonization, gasification, and liquefaction of coals and other solids fuels as they facilitate the incorporation of individual PAHs into a highly crosslinked matrix. A series of PAH and diphenylalkane-containing phenolic co-resites were prepared using phenol, with, as the second component, 2-naphthol, 4-hydroxy 9-diphenylmethane, 4, 4`-dihydroxydiphenylethane, 1-4(4-hydroxybenzyl)naphthalene, 9-(4-hydroxybenzyl) anthracene, and 9-(4-hydroxybenzyl) phenanthrene. A mole ratio of 3:1 (phenol:second phenolic constituent) was used. The virtually complete elimination of ether and methyl functions from the resoles by curing at 200{degree}C was monitored by solid-state {sup 13}C-NMR. The resites were also characterized by Fourier transform infrared spectroscopy. The volatile-matter contents of the PAH-containing resites were all higher than that of the normal resite. The carbonization of the 9-(4-hydroxybenzyl) anthracene-containing resite in a fluidized-bed reactor is used to illustrate the potential applications of the PAH-containing resites in fuel science.

  10. Glycerol acetals, kinetic study of the reaction between glycerol and formaldehyde

    International Nuclear Information System (INIS)

    Agirre, I.; Garcia, I.; Requies, J.; Barrio, V.L.; Gueemez, M.B.; Cambra, J.F.; Arias, P.L.

    2011-01-01

    The acetalization reaction between glycerol and formaldehyde using Amberlyst 47 acidic ion exchange resin was studied. These acetals can be obtained from renewable sources (bioalcohols and bioalcohol derived aldehydes) and seem to be good candidates for different applications such as oxygenated diesel additives. A preliminary kinetic study was performed in a batch stirred tank reactor studying the influence of different process parameters like temperature, feed composition and the stirring speed. A pseudo homogenous kinetic model able to explain the reaction mechanism was adjusted. Thus, the corresponding order of reaction was determined. Amberlyst 47 acidic ion exchange resin showed a fairly good behavior allowing 100% of selectivity towards acetals formation. However, the studied acetalization reaction showed high thermodynamic limitations achieving glycerol conversions around 50% using a stoichiometric feed ratio at 353 K. The product is a mixture of two isomers (1,3-Dioxan-5-ol and 1,3-dioxolane-4-methanol) and the conversion of 1,3-dioxolane-4-methanol into 1,3-Dioxan-5-ol was also observed. -- Highlights: → The reaction between glycerol and acetaldehyde shows thermodynamic limitations. → Amberlyst 47 ion exchange resins show 100% of selectivity. → A pseudo-homogeneous kinetic model is able to predict the reaction progress. → Isomerization reactions were observed from dioxalanes to dioxanes.

  11. N, Fe and WO3 modified TiO2 for degradation of formaldehyde

    International Nuclear Information System (INIS)

    Tong Haixia; Zhao Li; Li Dan; Zhang Xiongfei

    2011-01-01

    Graphical abstract: The undoped TiO 2 powder (T(0)) shows strong photoabsorption only at wavelengths shorter than 400 nm, and while Fe 3+ and N-doped TiO 2 nanoparticles show photoabsorption in visible region and the absorption edge shifts to a longer wavelength. WO 3 compounding also benefits the photoabsorption in visible region. Display Omitted Highlights: → The preparation of the catalysts co-doped by Fe, N and compounded by WO 3 . → The obvious sculptured 'pattern' of the catalysts doped by Fe in the SEM images. → Strengthened photoabsorption to visible light of the modified catalysts from UV-DRS analysis. - Abstract: Butyltitanate, ethanol and glacial acetic acid were chosen as titanium source, solvent and chelating agent, respectively, via a sol-gel method combined impregnation method to prepare N, Fe co-doped and WO 3 compounded photocatalyst TiO 2 powder. The synthesized products were characterized by X-ray diffraction (XRD), diffuse reflectance UV-Vis spectra (UV-DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Photocatalytic degradation of formaldehyde was employed to investigate the catalytic activity. The results show that the degradation rate is 77.61% in 180 min under UV light irradiation when the concentration of N is fixed on, and the optimum proportioning ratio of n(Fe):n(W):n(Ti) is 0.5:2:100.

  12. Synthesis and Characterization of Bio-Oil Phenol Formaldehyde Resin Used to Fabricate Phenolic Based Materials

    Directory of Open Access Journals (Sweden)

    Yong Cui

    2017-06-01

    Full Text Available In this study, bio-oil from the fast pyrolysis of renewable biomass was used as the raw material to synthesize bio-oil phenol formaldehyde (BPF resin—a desirable resin for fabricating phenolic-based material. During the synthesis process, paraformaldehyde was used to achieve the requirement of high solid content and low viscosity. The properties of BPF resins were tested. Results indicated that BPF resin with the bio-oil addition of 20% had good performance on oxygen index and bending strength, indicating that adding bio-oil could modify the fire resistance and brittleness of PF resin. The thermal curing behavior and heat resistance of BPF resins were investigated by differential scanning calorimetry (DSC and thermal gravimetric analysis (TGA. Results showed that adding bio-oil had an impact on curing characteristics and thermal degradation process of PF resin, but the influence was insignificant when the addition was relatively low. The chemical structure and surface characteristics of BPF resins were determined by Fourier transform infrared (FTIR spectroscopy and scanning electron microscopy (SEM. The analysis demonstrated that adding bio-oil in the amount of 20% was able to improve the crosslinking degree and form more hydrocarbon chains in PF resin.

  13. Studies of catalyst material for the electro-oxidation of methanol, ethanol, formaldehyde and formic acid

    International Nuclear Information System (INIS)

    Bajwa, S.Z.; Ahmed, R.

    2007-01-01

    Fuel cell is an electrochemical device that converts the chemical energy of reaction directly into the electrical energy. It is highly efficient and environment friendly device. Normally used fuel in fuel cells is hydrogen, but due to the convenience in handling some other liquid fuels are also used and now direct methanol fuel cells are available in the market. Rapid electro-oxidation of the fuel at the fuel cell electrode is necessary for its optimum use. In addition to the methanol, other liquid fuels can also be used in the fuel cell. In this work, cyclic voltammetric studies have been done for the electro-oxidation of the methanol, ethanol, formic acid and formaldehyde on fuel cell catalyst. Platinum electrode is characterized by the measurement of active surface area and roughness factor. Classical electrochemical equations have been employed to find out rate constants for electro-oxidation of methanol fuel and calculations have been carried out to find out thermodynamic parameters. Exchange current density has been evaluated with reference to catalyst by drawing polarization curves. (author)

  14. Cooling of interstellar formaldehyde by collision with helium: an accurate quantum mechanical calculation

    International Nuclear Information System (INIS)

    Garrison, B.J.

    1975-08-01

    In order to test a collisional pumping model as a mechanism for cooling the 6 cm and 2 cm doublets of interstellar formaldehyde, a quantum mechanical scattering calculation is performed. To obtain the intermolecular interaction between H 2 CO( 1 A 1 ) and He( 1 S) two calculations are performed, a Hartree-Fock (HF) potential surface and a configuration interaction (CI) surface. A basis set of better than ''triple zeta plus polarization'' quality is used to compute the HF portion of the potential energy surface. This portion is highly anisotropic and has a slight attraction arising from induction effects at intermolecular separations around 9 a.u. The HF surface is modified through a series of CI calculations. Correlation is found to have little effect in the strongly anisotropic repulsive region of the interaction potential but dominates the well and long-range regions. The maximum well depth is attained for in-plane approaches of He and lies in the range 35-40 0 K for arbitrary theta at center of mass separation of 7.5 a.u. The entire surface is fit to a spherical harmonic expansion to facilitate scattering applications. (auth)

  15. Gas phase hydrolysis of formaldehyde to form methanediol: impact of formic acid catalysis.

    Science.gov (United States)

    Hazra, Montu K; Francisco, Joseph S; Sinha, Amitabha

    2013-11-21

    We find that formic acid (FA) is very effective at facilitating diol formation through its ability to reduce the barrier for the formaldehyde (HCHO) hydrolysis reaction. The rate limiting step in the mechanism involves the isomerization of a prereactive collision complex formed through either the HCHO···H2O + FA and/or HCHO + FA···H2O pathways. The present study finds that the effective barrier height, defined as the difference between the zero-point vibrational energy (ZPE) corrected energy of the transition state (TS) and the HCHO···H2O + FA and HCHO + FA···H2O starting reagents, are respectively only ∼1 and ∼4 kcal/mol. These barriers are substantially lower than the ∼17 kcal/mol barrier associated with the corresponding step in the hydrolysis of HCHO catalyzed by a single water molecule (HCHO + H2O + H2O). The significantly lower barrier heights for the formic acid catalyzed pathway reveal a new important role that organic acids play in the gas phase hydrolysis of atmospheric carbonyl compounds.

  16. Chelation Ion Exchange Properties of 2, 4-Dihydroxyacetophenone-Biuret-Formaldehyde Terpolymer Resin

    Directory of Open Access Journals (Sweden)

    Sanjiokumar S. Rahangdale

    2009-01-01

    Full Text Available The terpolymer resin 2, 4-HABF has been synthesized by the condensation of 2, 4-dihydroxyacetophenone (2, 4-HA and biuret (B with formaldehyde (F in 1:1:2 molar ratios in presence of 2 M hydrochloric acid as catalyst. UV-Visible, IR and proton NMR spectral studies have been carried out to elucidate the structure of the resin. A terpolymer (2, 4-HABF proved to be a selective chelating ion exchange polymer for certain metals. Chelating ion-exchange properties of this polymer were studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+ and Pb2+ ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurement of the distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The polymer showed highest selectivity for Fe3+, Cu2+ ions than for Ni2+, Co2+, Zn2+, Cd2+, and Pb2+ ions. Study of distribution ratio as a formation of pH indicates that the amount of metal ion taken by resin is increases with the increasing pH of the medium.

  17. Amperometric Formaldehyde Sensor Based on a Pd Nanocrystal Modified C/Co2P Electrode

    Directory of Open Access Journals (Sweden)

    Huan Wang

    2017-01-01

    Full Text Available Ultrafine Pd nanocrystals were grown on the cobalt phosphide (Co2P decorated Vulcan XC-72 carbon (C/Co2P, which is realized by first implementing the corresponding metal precursor and then the further chemical reduction process. The as-synthesized C/Co2P/Pd composite was further constructed to form a gas permeable electrode. This electrode can be applied for formaldehyde (HCHO detection. The results demonstrate that the Co2P nanocrystal can significantly improve the sensing performance of the C/Co2P/Pd electrode for catalytic oxidation of HCHO, which is considered to be attributed to the effective electron transfer from Co2P to Pd in the C/Co2P/Pd composites. Furthermore, the assembled C/Co2P/Pd sensor exhibits high sensitivity of 617 nA/ppm and good selectivity toward various interfering gases such as NO2, NO, SO2, CO2, and CO. It also shows the excellent linear response that the correlation coefficient is 0.994 in the concentration range of 1–10 ppm. Therefore, the proposed cost-effective C/Co2P/Pd nanocomposite, which owns advantages such as high activity and good stability, has the potential to be applied as an effective electrocatalyst for amperometric HCHO detection.

  18. Atmospheric formaldehyde and acetaldehyde at the campus University of Hiroshima, Japan

    Directory of Open Access Journals (Sweden)

    Sonia Naomi Nomi

    2010-09-01

    Full Text Available Ambient levels of formaldehyde (HCHO and acetaldehyde (CH3CHO were measured at Hiroshima (Japan during spring and summer of 2005. Measurements of O3, NOx, and SO2 were simultaneously conducted, in an attempt to identify temporal profiles and sources for these aldehydes. Atmospheric aldehydes were collected using C18 silica gel cartridges coated with an acidic solution of 2, 4-dinitrophenylhydrazine (2,4-DNPH and analyzed by high performance liquid chromatography with UV/VIS detection adjusted to 360 nm. Summer concentrations were higher than spring levels. FA concentrations during spring period ranged from 0.50 to 1.05 ppb and AA concentrations ranged from 0.17 to 1.31 ppb; during summer their concentrations ranged from 1.55 to 4.12 ppb and 0. 34 to 2.03 ppb. Average FA/AA in spring and summer were 3.09 and 3.72 suggesting biogenic emissions of aldehydes. The levels of FA and AA, their temporal variations, and their concentration ratio (FA/AA indicated that photochemical reactions contributed significantly to the formation of atmospheric aldehydes at the study site.

  19. Effect of phenol formaldehyde resin as vulcanizing agent on flow behavior of HDPE/PB blend

    Directory of Open Access Journals (Sweden)

    Moayad N. Khalaf

    2014-07-01

    Full Text Available Thermoplastic elastomer (TPE based on High density polyethylene (HDPE/polybutadiene (HDPE/PB = 70/30 parts blends containing 1, 3, 5, 7 and 10 wt.% of dimethylol phenolic resin as a vulcanizing agent in the presence of SnCl2 as catalyst was prepared. The dimethylol phenolic resin was prepared in our laboratory. The blends were compounded in mixer-60 attached to a Haake rheochord meter-90. The rheological properties were measured at temperatures 140, 160, 180 and 200 °C. The linearity of the flow curve appeared for 5% of the vulcanizing agent. The shear stress and shear viscosity have increased upon increasing the shear rate over a range of loading levels of vulcanizing agent of 1%, 3%, 5%, 7% and 10%. This may be attributed to the increased vulcanization between polyethylene and the rubber blend. The flow behavior index of the system shows a pseudo plastic nature behavior (since n < 1. The consistency index (K increased with the increase in the phenol formaldehyde resin content and the temperature. Hence, the increase in the value of the consistency index (K of the polymer melts refers to more viscous materials prepared. The activation energy for the TPE blends fluctuated indicating that there is phase separation; where each polymer behaved separately. This study showed that HDPE/PB blends are characterized with good rheological properties, which can be recommended to be processed with the injection molding technique.

  20. FABRICATION AND PROPERTIES OVERCOATED RESORCINOL-FORMALDEHYDE SHELLS FOR OMEGA EXPERIMENTS

    International Nuclear Information System (INIS)

    NIKROO, A; CZECHOWICZ, D; PAGUIO, R; GREENWOOD, A.L; TAKAGI, M.

    2003-09-01

    OAK-B135 New high gain designs for direct drive ignition on NIF require foam shells. Scaled down versions of these designs are needed for near term experiments on the OMEGA laser facility at the Laboratory Laser Energetics (LLE). These shells need to be about 1 mm in diameter and 50-100 (micro)m wall thickness and densities of 100-250 mg/cc. In addition, a full density permeation seal needs to be deposited for retention of the fill gas at room temperature or the ice at cryogenic temperatures. They have fabricated such shells using Resorcinol-formaldehyde (R/F) as the selected foam material due to its transparency in the optical region. Extensive characterization of the wall uniformity of these shells has been performed. The foam shells have ∼ 5%-6% non-concentricities on the average. A full density permeation seal has been deposited on the R/F shells using two different techniques. In the first technique R/F shells are coated directly with plasma polymer to thicknesses of 3-4 (micro)m. In the second technique, R/F shells are coated with polyvinylphenol, using a chemical interfacial polymerization technique. Data on surface finish and gas retention for R/F shells coated by both methods are provided

  1. Raman Spectra of Methane, Ethylene, Ethane, Dimethyl ether, Formaldehyde and Propane for Combustion Applications

    KAUST Repository

    Magnotti, G.

    2015-05-09

    Spontaneous Raman scattering measurements of temperature and major species concentration in hydrocarbon-air flames require detailed knowledge of the Raman spectra of the hydrocarbons present when fuels more complex than methane are used. Although hydrocarbon spectra have been extensively studied at room temperature, there are no data available at higher temperatures. Quantum mechanical calculations, when available are not sufficiently accurate for combustion applications. This work presents experimental measurements of spontaneous Stokes-Raman scattering spectra of methane, ethylene, ethane, dimethyl ether, formaldehyde and propane in the temperature range 300-860 K. Raman spectra from heated hydrocarbons jets have been collected with a higher resolution than is generally employed for Raman measurements in combustion applications. A set of synthetic spectra have been generated for each hydrocarbon, providing the basis for extrapolation to higher temperatures. The spectra provided here will enable simultaneous measurements of multiple hydrocarbons in flames. This capability will greatly extend the range of applicability of Raman measurements in combustion applications. In addition, the experimental spectra provide a validation dataset for quantum mechanical models.

  2. DFT analysis of the reaction paths of formaldehyde decomposition on silver.

    Science.gov (United States)

    Montoya, Alejandro; Haynes, Brian S

    2009-07-16

    Periodic density functional theory is used to study the dehydrogenation of formaldehyde (CH(2)O) on the Ag(111) surface and in the presence of adsorbed oxygen or hydroxyl species. Thermodynamic and kinetic parameters of elementary surface reactions have been determined. The dehydrogenation of CH(2)O on clean Ag(111) is thermodynamically and kinetically unfavorable. In particular, the activation energy for the first C-H bond scission of adsorbed CH(2)O (25.8 kcal mol(-1)) greatly exceeds the desorption energy for molecular CH(2)O (2.5 kcal mol(-1)). Surface oxygen promotes the destruction of CH(2)O through the formation of CH(2)O(2), which readily decomposes to CHO(2) and then in turn to CO(2) and adsorbed hydrogen. Analysis of site selectivity shows that CH(2)O(2), CHO(2), and CHO are strongly bound to the surface through the bridge sites, whereas CO and CO(2) are weakly adsorbed with no strong preference for a particular surface site. Dissociation of CO and CO(2) on the Ag(111) surface is highly activated and therefore unfavorable with respect to their molecular desorption.

  3. Characterizing boundary layer height using surface and column measurements of NO2 and formaldehyde

    Science.gov (United States)

    Valin, L.; Szykman, J.; Long, R.; Whitehill, A.; Williams, D. J.; Knepp, T. N.; Crawford, J. H.; Al-Saadi, J. A.; Judd, L.; Brown, S.; Matichuk, R.; Tonnesen, G.; Appel, W.; Hogrefe, C.; Abuhassan, N.; Cede, A.; Spinei, E.; Herman, J. R.; Swap, R.; Cohen, R. C.; Fried, A.; Weinheimer, A. J.

    2017-12-01

    The rate of vertical mixing near the surface determines the rate of human exposure to emitted pollutants and also influences the rate at which ozone and particulate matter are formed. To characterize the variability of atmospheric composition near the surface and above, the EPA Office of Research and Development has deployed instruments to measure surface and column concentrations of NO2, an emitted species, and formaldehyde (HCHO) during KORUS-AQ (May - June 2016, Seoul, Korea), UWFPS (Jan-Feb 2016, Salt Lake City) and LMOS (May - June, 2017, Lake Michigan). We compare the mixed layer height determined by aerosol backscatter profiles to a value determined by dividing the NO2 and HCHO column density (molecule cm-2) by its surface concentration (molecule cm-3), using linear regression to remove influence of layers aloft (y-intercept), such as subtraction of the stratospheric NO2 column. We evaluate our findings by using aircraft soundings of NO2 and HCHO and discuss the implications with respect to photochemical transport modeling results from CMAQ and space-based satellite retrievals. Finally we discuss an overall strategy to make these measurements part of routine monitoring at Photochemical Assessment Monitoring System locations (PAMS).

  4. Reduction of Endogenous Melatonin Accelerates Cognitive Decline in Mice in a Simulated Occupational Formaldehyde Exposure Environment

    Directory of Open Access Journals (Sweden)

    Yufei Mei

    2016-02-01

    Full Text Available Individuals afflicted with occupational formaldehyde (FA exposure often suffer from abnormal behaviors such as aggression, depression, anxiety, sleep disorders, and in particular, cognitive impairments. Coincidentally, clinical patients with melatonin (MT deficiency also complain of cognitive problems associated with the above mental disorders. Whether and how FA affects endogenous MT metabolism and induces cognitive decline need to be elucidated. To mimic occupational FA exposure environment, 16 healthy adult male mice were exposed to gaseous FA (3 mg/m3 for 7 consecutive days. Results showed that FA exposure impaired spatial memory associated with hippocampal neuronal death. Biochemical analysis revealed that FA exposure elicited an intensive oxidative stress by reducing systemic glutathione levels, in particular, decreasing brain MT concentrations. Inversely, intraperitoneal injection of MT markedly attenuated FA-induced hippocampal neuronal death, restored brain MT levels, and reversed memory decline. At tissue levels, injection of FA into the hippocampus distinctly reduced brain MT concentrations. Furthermore, at cellular and molecular levels, we found that FA directly inactivated MT in vitro and in vivo. These findings suggest that MT supplementation contributes to the rescue of cognitive decline, and may alleviate mental disorders in the occupational FA-exposed human populations.

  5. The Irritating Effects Of Exposure To Formaldehyde In User Students Of The Human Anatomy Laboratory

    Directory of Open Access Journals (Sweden)

    Jalles Dantas de Lucena

    2017-07-01

    Full Text Available Formaldehyde (FA is commonly used in cadaver fixation for years. FA vapors are released during the dissection process and macroscopic study of preserved anatomical pieces, raising their concentration in the Anatomy laboratory, causing greater exposure for students and teachers. Therefore, the objective of this study was to investigate toxic reactions in 37 students, through a questionnaire, produced by exposure to FA used for preservation of cadaveric material used in Anatomy, Morphofunctional Department, Faculdades Integradas de Patos (FIP, Brazil. Of the 37 interviewees, 26 (70.3% were affected by the unpleasant and irritating smell of FA, 10 (27% had no problems, and 1 (2.7% did not tolerate an irritation produced by FA, ​​not participating in the laboratory practical classes. Exposure to FA was followed by several symptoms: excessive lacrimation (54%, itchy eyes (48.5%, redness of the eyes (40.6%, coryza or congested nose (35.2% and respiratory distress (29.7%, with persistent symptoms during the permanence in the laboratory for 32.5% of the students. All students wear a lab coat for individual protection. However, only 8% used mascara and did not wear glasses, increasing the risk of contamination. Medical schools should encourage the use of Personal Protective Equipment (PPE for the manipulation of FA, ensuring the protection of students and teachers in the Anatomy laboratory. Besides finding alternatives for the replacement of FA in the conservation of corpses.

  6. Raman Spectra of Methane, Ethylene, Ethane, Dimethyl ether, Formaldehyde and Propane for Combustion Applications

    KAUST Repository

    Magnotti, G.; KC, Utsav; Varghese, P.L.; Barlow, R.S.

    2015-01-01

    Spontaneous Raman scattering measurements of temperature and major species concentration in hydrocarbon-air flames require detailed knowledge of the Raman spectra of the hydrocarbons present when fuels more complex than methane are used. Although hydrocarbon spectra have been extensively studied at room temperature, there are no data available at higher temperatures. Quantum mechanical calculations, when available are not sufficiently accurate for combustion applications. This work presents experimental measurements of spontaneous Stokes-Raman scattering spectra of methane, ethylene, ethane, dimethyl ether, formaldehyde and propane in the temperature range 300-860 K. Raman spectra from heated hydrocarbons jets have been collected with a higher resolution than is generally employed for Raman measurements in combustion applications. A set of synthetic spectra have been generated for each hydrocarbon, providing the basis for extrapolation to higher temperatures. The spectra provided here will enable simultaneous measurements of multiple hydrocarbons in flames. This capability will greatly extend the range of applicability of Raman measurements in combustion applications. In addition, the experimental spectra provide a validation dataset for quantum mechanical models.

  7. Prebiotic Synthesis of Autocatalytic Products From Formaldehyde-Derived Sugars as the Carbon and Energy Source

    Science.gov (United States)

    Weber, Arthur L.

    2003-01-01

    Our research objective is to understand and model the chemical processes on the primitive Earth that generated the first autocatalytic molecules and microstructures involved in the origin of life. Our approach involves: (a) investigation of a model origin-of-life process named the Sugar Model that is based on the reaction of formaldehyde- derived sugars (trioses and tetroses) with ammonia, and (b) elucidation of the constraints imposed on the chemistry of the origin of life by the fixed energies and rates of C,H,O-organic reactions under mild aqueous conditions. Recently, we demonstrated that under mild aqueous conditions the Sugar Model process yields autocatalytic products, and generates organic micropherules (2-20 micron dia.) that exhibit budding, size uniformity, and chain formation. We also discovered that the sugar substrates of the Sugar Model are capable of reducing nitrite to ammonia under mild aqueous conditions. In addition studies done in collaboration with Sandra Pizzarrello (Arizona State University) revealed that chiral amino acids (including meteoritic isovaline) catalyze both the synthesis and specific handedness of chiral sugars. Our systematic survey of the energies and rates of reactions of C,H,O-organic substrates under mild aqueous conditions revealed several general principles (rules) that govern the direction and rate of organic reactions. These reactivity principles constrain the structure of chemical pathways used in the origin of life, and in modern and primitive metabolism.

  8. Optimization of the synthesis based on Resorcine and formaldehyde to obtain carbon nanoxérogels

    Science.gov (United States)

    Zweg, A.; Elaloui, E.; Nouri, S.; Moussaoui, Y.

    2012-02-01

    The sol-gel method consists on obtaining very pure products from selected precursors. Indeed, synthesizing very pure activated carbon (> 99% carbon) using organic precursors containing only carbon and oxygen as hetero atoms to form a polymeric resin by pyrolysis. The proposed synthesis reaction is in the border of two sciences: the Sol-gel and polymerization. The polymerization by mechanism followed by the initiation and propagation, the sol-gel by evolution of the media environment starting with a solution of various ingredients to have the particle's sol in the emulsion solvent. The sol turns into a gel which is the result of three-dimensional crosslinking of the material trapping the solvent. In this work we propose to introduce a new method of synthesis of these nanoxérogels by polycondensation of resorcinol with formaldehyde in two different media (water and acetone) in the presence of two catalysts (acetic acid and sodium carbonate). By varying the following parameters: solvent, nature and quantity of catalyst, 16 samples were obtained. By the method of factorial design (2k): an optimization is realized by following three characteristics of nanoxerogels prepared: the density, the gel time and performance. The results indicate the best conditions for the synthesis of a carbon nanoxerogel: the lowest quantity of acid catalyst in aqueous media (A5).

  9. PEMBUATAN AYAKAN MOLEKULER BERBASIS KARBON UNTUK PEMISAHAN N2/O2 DARI PIROLISIS RESIN PHENOL FORMALDEHYDE

    Directory of Open Access Journals (Sweden)

    Imam Prasetyo

    2012-02-01

    Full Text Available Proses pemisahan campuran gas dengan menggunakan carbon molecular sieve (CMS atau ayakan molekuler berbasis karbon merupakan teknologi proses pemisahan yang mulai banyak diterapkan di dalam industri kimia. Dalam penelitian ini, CMS untuk pemisahan N2 dari udara dibuat dari pirolisis bahan polimer sintetis yaitu resin phenol formaldehyde (PF. Prekursor yang berupa resin tersebut dipanaskan dalam retort pada suhu 400-950oC selama 0,5-3 jam yang disertai dengan pengaliran gas N2 ke dalam retort dengan laju 100 mL/jam. Dengan proses pirolisis, atom-atom non-karbon penyusun bahan polimer akan terurai dan menguap sehingga hanya menyisakan arang karbon dengan struktur kerangka atom karbon yang sesuai dengan struktur kerangka dasar rantai polimer. Kemudian karbon hasil prolisis tersebut dipanaskan lebih lanjut pada suhu 750-950oC sambil dialiri gas CO2 selama 1 jam. Pada kondisi ini karbon akan mengalami proses gasifikasi parsial sehingga terbentuk karbon dengan porositas tinggi. Melalui rekayasa proses polimerisasi dan karbonisasi dihasilkan material karbon berpori yang mayoritas porinya adalah mikropori dengan ukuran pori efektif < 2 nm yang dapat dikategorikan sebagai CMS yang dapat dipergunakan untuk memisahkan campuran gas N2-O2.  Pada penelitian ini dihasilkan CMS dengan selektifitas kinetis DN2/DO2 sekitar 3.

  10. Gas Generation Testing of Spherical Resorcinol-Formaldehyde (sRF) Resin

    Energy Technology Data Exchange (ETDEWEB)

    Colburn, Heather A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bryan, Samuel A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Camaioni, Donald M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mahoney, Lenna A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adami, Susan R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2018-01-19

    This report describes gas generation testing of the spherical resorcinol-formaldehyde (sRF) resin that was conducted to support the technology maturation of the LAWPS facility. The current safety basis for the LAWPS facility is based primarily on two studies that had limited or inconclusive data sets. The two studies indicated a 40% increase in hydrogen generation rate of water (as predicted by the Hu model) with sRF resin over water alone. However, the previous studies did not test the range of conditions (process fluids and temperatures) that are expected in the LAWPS facility. Additionally, the previous studies did not obtain replicate test results or comparable liquid-only control samples. All of the testing described in this report, conducted with water, 0.45M nitric acid, and waste simulants with and without sRF resin, returned hydrogen generation rates that are within the current safety basis for the facility of 1.4 times the Hu model output for water.

  11. Elevated urine formaldehyde in elderly patients with primary open angle glaucoma

    Directory of Open Access Journals (Sweden)

    Ying Cui

    2016-03-01

    Full Text Available AIM: To investigate the risk factor of primary open angle glaucoma (POAG, which is the leading cause of irreversible blindness worldwide. An abnormally high level of endogenous formaldehyde (FA has recently been found correlated with cell death and neurodegenerative disease, raising the possibility of a putative correlation of abnormal endogenous FA with POAG. METHODS: Thirty-four elderly patients with POAG and sixteen healthy controls were enrolled. Glaucomatous visual defects were present at both the functional (visual field and structural [retinal nerve fiber layer (RNFL thickness] levels. Morning urine samples were obtained and were analyzed by high-performance liquid chromatography (HPLC to detect the endogenous FA level in a double blind manner. RESULTS: Patients with POAG (P<0.05 had significantly higher urine FA levels. The urine FA level of patients with severe visual field defects [mean deviation (MD≥12 dB] was significantly (P<0.001 greater than that of patients with mild to moderate defects (MD<12 dB. By optical coherence tomography (OCT, the superior and inferior RNFL thickness of POAG group was significantly (P<0.001 thinner than in controls. Furthermore, the superior and inferior thinning of the RNFL was correlated with the elevation of urine FA concentration. CONCLUSION: Endogenous FA level is positively correlated with the neuronal defects of POAG.

  12. Impact of Formaldehyde Addition on Auto-Ignition in Internal-Combustion Engines

    Science.gov (United States)

    Kuwahara, Kazunari; Ando, Hiromitsu; Furutani, Masahiro; Ohta, Yasuhiko

    By employing a direct-injection diesel engine equipped with a common-rail type of injection system, by adding formaldehyde (CH2O) to the intake air, and by changing the fuel-injection timing, the compression ratio and the intake-air temperature, a mechanism for CH2O as a fuel additive to affect auto-ignition was discussed. Unlike an HCCI type of engine, the diesel engine can expose an air-fuel mixture only to a limited range of the in-cylinder temperature before the ignition, and can separate low- and high-temperature parts of the mechanism. When low-temperature oxidation starts at a temperature above 900K, there are cases that the CH2O advances the ignition timing. Below 900K, to the contrary, it always retards the timing. It is because, above 900K, a part of the CH2O changes into CO together with H2O2 as an ignition promoter. Below 900K, on the other hand, the CH2O itself acts as an OH radical scavenger against cool-flame reaction, from the beginning of low-temperature oxidation. Then, the engine was modified for its extraordinary function as a gasoline-knocking generator, in order that an effect of CH2O on knocking could be discussed. The CH2O retards the onset of auto-ignition of an end gas. Judging from a large degree of the retardation, the ignition is probably triggered below 900K.

  13. Ion Exchange Modeling Of Cesium Removal From Hanford Waste Using Spherical Resorcinol-Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hamm, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2007-06-27

    This report discusses the expected performance of spherical Resorcinol-Formaldehyde (RF) ion exchange resin for the removal of cesium from alkaline Hanford radioactive waste. Predictions of full scale column performance in a carousel mode are made for the Hot Commissioning, Envelope B, and Subsequent Operations waste compositions under nominal operating conditions and for perturbations from the nominal. Only the loading phase of the process cycle is addressed in this report. Pertinent bench-scale column tests, kinetic experiments, and batch equilibrium experiments are used to estimate model parameters and to benchmark the ion-exchange model. The methodology and application presented in this report reflect the expected behavior of spherical RF resin manufactured at the intermediate-scale (i.e., approximately 100 gallon batch size; batch 5E-370/641). It is generally believed that scale-up to production-scale in resin manufacturing will result in similarly behaving resin batches whose chemical selectivity is unaffected while total capacity per gram of resin may vary some. As such, the full-scale facility predictions provided within this report should provide reasonable estimates of production-scale column performance.

  14. Nine years of global hydrocarbon emissions based on source inversion of OMI formaldehyde observations

    Directory of Open Access Journals (Sweden)

    M. Bauwens

    2016-08-01

    Full Text Available As formaldehyde (HCHO is a high-yield product in the oxidation of most volatile organic compounds (VOCs emitted by fires, vegetation, and anthropogenic activities, satellite observations of HCHO are well-suited to inform us on the spatial and temporal variability of the underlying VOC sources. The long record of space-based HCHO column observations from the Ozone Monitoring Instrument (OMI is used to infer emission flux estimates from pyrogenic and biogenic volatile organic compounds (VOCs on the global scale over 2005–2013. This is realized through the method of source inverse modeling, which consists in the optimization of emissions in a chemistry-transport model (CTM in order to minimize the discrepancy between the observed and modeled HCHO columns. The top–down fluxes are derived in the global CTM IMAGESv2 by an iterative minimization algorithm based on the full adjoint of IMAGESv2, starting from a priori emission estimates provided by the newly released GFED4s (Global Fire Emission Database, version 4s inventory for fires, and by the MEGAN-MOHYCAN inventory for isoprene emissions. The top–down fluxes are compared to two independent inventories for fire (GFAS and FINNv1.5 and isoprene emissions (MEGAN-MACC and GUESS-ES. The inversion indicates a moderate decrease (ca. 20 % in the average annual global fire and isoprene emissions, from 2028 Tg C in the a priori to 1653 Tg C for burned biomass, and from 343 to 272 Tg for isoprene fluxes. Those estimates are acknowledged to depend on the accuracy of formaldehyde data, as well as on the assumed fire emission factors and the oxidation mechanisms leading to HCHO production. Strongly decreased top–down fire fluxes (30–50 % are inferred in the peak fire season in Africa and during years with strong a priori fluxes associated with forest fires in Amazonia (in 2005, 2007, and 2010, bushfires in Australia (in 2006 and 2011, and peat burning in Indonesia (in 2006 and 2009, whereas

  15. Plasma regeneration of mineral adsorbents for the precipitation of formaldehyde from exhaust gases of biogas engines; Plasmaregeneration mineralischer Adsorbentien zur Formaldehydabscheidung aus Abgasen von Biogas-Motoren

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Siegfried; Saulich, Katja [Leibniz-Institut fuer Plasmaforschung und Technologie, Greifswald (Germany); Schomburg, Joachim [DURTEC, Neubrandenburg (Germany)

    2013-10-01

    Formaldehyde.is a harmful ambient air pollutant which can be produced by incomplete combustion processes, e.g. in power plants or combustion engines. Adsorbents are widely applied in the area of cleaning as well as enrichment of gas components. In this study, we designed a bench-scale experiment to investigate a gas pollution treatment technique, which integrated the adsorption process and the plasma treatment for formaldehyde removal from gas streams. The mineral granulate used consisted of 80% halloysite and showed a good adsorption capacity for formaldehyde. In the discharge step, the adsorbed formaldehyde molecules were decomposed to CO{sub 2}, CO and hydrocarbons. For the further optimization of the method the influence of the power and the pulse break ratio of sustaining voltage were tested. Further the decomposition performance on adsorbed formaldehyde molecules was studied depending on space-time, a 10% oxygen fraction of the carrier gas, and the influence of temperature. It was shown that with the chosen plasma method the absorber material could be loaded repeatedly and subsequently regenerated at a low input discharge power. (orig.)

  16. Fe atoms trapped on graphene as a potential efficient catalyst for room-temperature complete oxidation of formaldehyde: a first-principles investigation

    KAUST Repository

    Guo, Huimin; Li, Min; Liu, Xin; Meng, Changgong; Linguerri, Roberto; Han, Yu; Chambaud, Gilberte

    2017-01-01

    We investigated the oxidation of formaldehyde, one of the major indoor air pollutants, into CO2 and H2O over Fe atoms trapped in defects on graphene by first-principles based calculations. These trapped Fe atoms are not only stable to withstand interference from the reaction environments but are also efficient in catalyzing the reactions between coadsorbed O-2 and formaldehyde. The oxidation of formaldehyde starts with the formation of a peroxide-like intermediate and continues by its dissociation into. eta(1)-OCHO coadsorbed with an OH radical. Then, the adsorbed OCHO undergoes conformational changes and hydride transfer, leading to the formation of H2O and CO2. Subsequent adsorption of O2 or formaldehyde facilitates desorption of H2O and a new reaction cycle initiates. The calculated barriers for formation and dissociation of the peroxide-like intermediate are 0.43 and 0.40 eV, respectively, and those for conformation changes and hydride transfer are 0.47 and 0.13 eV, respectively. These relatively low barriers along the reaction path suggest the potential high catalytic performance of trapped Fe atoms for formaldehyde oxidation.

  17. Fe atoms trapped on graphene as a potential efficient catalyst for room-temperature complete oxidation of formaldehyde: a first-principles investigation

    KAUST Repository

    Guo, Huimin

    2017-03-24

    We investigated the oxidation of formaldehyde, one of the major indoor air pollutants, into CO2 and H2O over Fe atoms trapped in defects on graphene by first-principles based calculations. These trapped Fe atoms are not only stable to withstand interference from the reaction environments but are also efficient in catalyzing the reactions between coadsorbed O-2 and formaldehyde. The oxidation of formaldehyde starts with the formation of a peroxide-like intermediate and continues by its dissociation into. eta(1)-OCHO coadsorbed with an OH radical. Then, the adsorbed OCHO undergoes conformational changes and hydride transfer, leading to the formation of H2O and CO2. Subsequent adsorption of O2 or formaldehyde facilitates desorption of H2O and a new reaction cycle initiates. The calculated barriers for formation and dissociation of the peroxide-like intermediate are 0.43 and 0.40 eV, respectively, and those for conformation changes and hydride transfer are 0.47 and 0.13 eV, respectively. These relatively low barriers along the reaction path suggest the potential high catalytic performance of trapped Fe atoms for formaldehyde oxidation.

  18. Gas-phase thermolysis reaction of formaldehyde diperoxide. Kinetic study and theoretical mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Jorge, Nelly Lidia [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Av. Las Palmeras 4, 18100 Armilla, Granada (Spain); Area de Quimica Fisica Facultad de Ciencias Exactas y Naturales y Agrimensura, UNNE, Avda. Libertad 5460, 3400 Corrientes (Argentina); Romero, Jorge Marcelo [Area de Quimica Fisica Facultad de Ciencias Exactas y Naturales y Agrimensura, UNNE, Avda. Libertad 5460, 3400 Corrientes (Argentina); Grand, Andre [INAC, SCIB, Laboratoire ' Lesions des Acides Nucleiques' , UMR CEA-UJF E3, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble cedex 9 (France); Hernandez-Laguna, Alfonso, E-mail: ahlaguna@ugr.es [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Av. Las Palmeras 4, 18100 Armilla, Granada (Spain)

    2012-01-17

    Highlights: Black-Right-Pointing-Pointer Kinetic and mechanism of the gas-phase thermolysis of tetroxane were determined. Black-Right-Pointing-Pointer Gas chromatography and computational potential energy surfaces were performed. Black-Right-Pointing-Pointer A mechanism in steps looked like the most probable mechanism. Black-Right-Pointing-Pointer A spin-orbit coupling appeared at the singlet and triple diradical open structures. Black-Right-Pointing-Pointer A non-adiabatic crossing from the singlet to the triplet state occurred. - Abstract: Gas-phase thermolysis reaction of formaldehyde diperoxide (1,2,4,5-tetroxane) was performed in an injection chamber of a gas chromatograph at a range of 463-503 K. The average Arrhenius activation energy and pre-exponential factor were 29.3 {+-} 0.8 kcal/mol and 5.2 Multiplication-Sign 10{sup 13} s{sup -1}, respectively. Critical points and reaction paths of the ground singlet and first triplet potential energy surfaces (PES) were calculated, using DFT method at BHANDHLYP/6-311+G{sup Asterisk-Operator Asterisk-Operator} level of the theory. Also, G3 calculations were performed on the reactant and products. Reaction by the ground-singlet and first-triplet states turned out to be endothermic and exothermic, respectively. The mechanism in three steps seemed to be the most probable one. An electronically non-adiabatic process appeared, in which a crossing, at an open diradical structure, from the singlet to the triplet state PES occurred, due to a spin-orbit coupling, yielding an exothermic reaction. Theoretical kinetic constant coming from the non- adiabatic transition from the singlet to the triplet state agrees with the experimental values.

  19. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    International Nuclear Information System (INIS)

    Wang, Jinlong; Yunus, Rizwangul; Li, Jinge; Li, Peilin; Zhang, Pengyi; Kim, Jeonghyun

    2015-01-01

    Graphical abstract: - Highlights: • The MnO x particles assembled with nanosheets were uniformly coated on PET fibers. • The growth process of MnO x layer on PET is clearly clarified. • MnO x /PET showed good activity for HCHO decomposition at room temperature. • MnO x /PET material is promising for indoor air purification due to its light, flexible and low air-resistant properties. - Abstract: Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnO x ) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnO x /PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnO x layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO 4 and then surface-deposition of MnO x particles from the bulk phase. The MnO x particles assembled with nanosheets were uniformly coated on the PET fibers. MnO x /PET showed good activity for HCHO decomposition at room temperature which followed the Mars–van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m 3 , space velocity ∼17,000 h −1 and relative humidity∼50%. This research provides a facile method to deposit active MnO x onto polymers with low air resistance, and composite MnO x /PET material is promising for indoor air purification.

  20. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinlong [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center for Regional Environmental Quality (China); Yunus, Rizwangul [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Xinjiang Zhongtai Chemical Company, Xinjiang 831511 (China); Li, Jinge; Li, Peilin [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Zhang, Pengyi, E-mail: zpy@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center for Regional Environmental Quality (China); Kim, Jeonghyun [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center for Regional Environmental Quality (China)

    2015-12-01

    Graphical abstract: - Highlights: • The MnO{sub x} particles assembled with nanosheets were uniformly coated on PET fibers. • The growth process of MnO{sub x} layer on PET is clearly clarified. • MnO{sub x}/PET showed good activity for HCHO decomposition at room temperature. • MnO{sub x}/PET material is promising for indoor air purification due to its light, flexible and low air-resistant properties. - Abstract: Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnO{sub x}) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnO{sub x}/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnO{sub x} layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO{sub 4} and then surface-deposition of MnO{sub x} particles from the bulk phase. The MnO{sub x} particles assembled with nanosheets were uniformly coated on the PET fibers. MnO{sub x}/PET showed good activity for HCHO decomposition at room temperature which followed the Mars–van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m{sup 3}, space velocity ∼17,000 h{sup −1} and relative humidity∼50%. This research provides a facile method to deposit active MnO{sub x} onto polymers with low air resistance, and composite MnO{sub x}/PET material is promising for indoor air purification.

  1. Laser-Based and Ultra-Portable Gas Sensor for Indoor and Outdoor Formaldehyde (HCHO) Monitoring

    Science.gov (United States)

    Shutter, J. D.; Allen, N.; Paul, J.; Thiebaud, J.; So, S.; Scherer, J. J.; Keutsch, F. N.

    2017-12-01

    While used as a key tracer of oxidative chemistry in the atmosphere, formaldehyde (HCHO) is also a known human carcinogen and is listed and regulated by the United States EPA as a hazardous air pollutant. Combustion processes and photochemical oxidation of volatile organic compounds (VOCs) are the major outdoor sources of HCHO, and building materials and household products are ubiquitous sources of indoor HCHO. Due to the ease with which humans can be exposed to HCHO, it is imperative to monitor levels of both indoor and outdoor HCHO exposure in both short and long-term studies.High-quality direct and indirect methods of quantifying HCHO mixing ratios exist, but instrument size and user-friendliness can make them cumbersome or impractical for certain types of indoor and long-term outdoor measurements. In this study, we present urban HCHO measurements by using a new, commercially-available, ppbv-level accurate HCHO gas sensor (Aeris Technologies' MIRA Pico VOC Laser-Based Gas Analyzer) that is highly portable (29 cm x 20 cm x 10 cm), lightweight (3 kg), easy-to-use, and has low power (15 W) consumption. Using an ultra-compact multipass cell, an absorption path length of 13 m is achieved, resulting in a sensor capable of achieving ppbv/s sensitivity levels with no significant spectral interferences.To demonstrate the utility of the gas sensor for emissions measurements, a GPS was attached to the sensor's housing in order to map mobile HCHO measurements in real-time around the Boston, Massachusetts, metro area. Furthermore, the sensor was placed in residential and industrial environments to show its usefulness for indoor and outdoor pollution measurements. Lastly, we show the feasibility of using the HCHO sensor (or a network of them) in long-term monitoring stations for hazardous air pollutants.

  2. Formaldehyde and Glyoxal Measurements as Tracers of Oxidation Chemistry in the Amazon Basin

    Science.gov (United States)

    Thayer, M. P.; Dorris, M. R.; Keutsch, F. N.; Springston, S. R.; Jimenez, J. L.; Palm, B. B.; Seco, R.; Kim, S.; Yee, L.; Wernis, R. A.; Goldstein, A. H.; Isaacman-VanWertz, G. A.; Liu, Y.; Martin, S. T.

    2015-12-01

    Formaldehyde (HCHO) and glyoxal (CHOCHO) are important tracers for oxidative processes in the atmosphere such as oxidation of volatile organic compounds (VOCs) and production of HO2 radicals by photolysis or reaction with OH. Products of VOC oxidation and radical cycling, such as aerosols and tropospheric ozone, have direct impacts on human health. During the Green Ocean Amazon campaign (GoAmazon2014/5), HCHO and CHOCHO measurements were obtained together with OH, RO2+HO2, CO, CO2, O3, NOx, (o)VOCs, and aerosol particle size distribution. HCHO concentration was measured by the Madison FIber Laser-Induced Fluorescence (FILIF) instrument, while CHOCHO concentrations were collected by the Madison Laser-Induced Phosphorescence (Mad-LIP) instrument. Here we present data collected during 2014 at the T3 field site, 60 km to the west of Manaus, Brazil (3°12'47.82"S, 60°35'55.32"W). The T3 GoAmazon site varies between sampling strictly pristine (biogenic) emissions and influence from anthropogenic emissions from Manaus, depending on meteorological conditions. Here we present overall trends and regimes observed during the campaign, with a focus on HCHO, CHOCHO, and related species within the context of VOC oxidation and secondary pollutant production. We acknowledge the support from the Central Office of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA), the Instituto Nacional de Pesquisas da Amazonia (INPA), and the Universidade do Estado do Amazonia (UEA). The work was conducted under 001030/2012-4 of the Brazilian National Council for Scientific and Technological Development (CNPq). Data were collected from the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a U.S. Department of Energy Office of Science user facility sponsored by the Office of Biological and Environmental Research. Additionally, we acknowledge logistical support from the ARM Climate Research Facility. Additional funding from: NSF GRFP DGE-1256259, and NSF AGS-1051338

  3. Sources and Potential Photochemical Roles of Formaldehyde in an Urban Atmosphere in South China

    Science.gov (United States)

    Wang, Chuan; Huang, Xiao-Feng; Han, Yu; Zhu, Bo; He, Ling-Yan

    2017-11-01

    Formaldehyde (HCHO) is an important intermediate in tropospheric photochemistry. However, study of its evolution characteristics under heavy pollution conditions in China is limited, especially for high temporal resolutions, making it difficult to analyze its sources and environmental impacts. In this study, ambient levels of HCHO were monitored using a proton-transfer reaction mass spectrometer at an urban site in the Pearl River Delta of China. Continuous monitoring campaigns were conducted in the spring, summer, fall, and winter in 2016. The highest averaged HCHO concentrations were observed in autumn (5.1 ± 3.1 ppbv) and summer (5.0 ± 4.4 ppbv), followed by winter (4.2 ± 2.2 ppbv) and spring (3.4 ± 1.6 ppbv). The daily maximum of HCHO occurs in the early afternoon and shows good correlations with O3 and the secondary organic aerosol tracer during the day, revealing close relationships between ambient HCHO and secondary formations in Shenzhen, especially in summer and autumn. The daytime HCHO is estimated to be the major contributor to O3 formation and OH radical production, indicating that HCHO plays a key role in the urban atmospheric photochemical reactions. Anthropogenic secondary formation was calculated to be the dominant source of HCHO using a photochemical age-based parameterization method, with an average proportion of 39%. The contributions of biogenic sources in summer (41%) and autumn (39%) are much higher than those in spring (26%) and winter (28%), while the contributions of anthropogenic primary sources in spring (20%) and winter (18%) are twice those in summer (9%) and autumn (9%).

  4. Kinetics based reaction optimization of enzyme catalyzed reduction of formaldehyde to methanol with synchronous cofactor regeneration.

    Science.gov (United States)

    Marpani, Fauziah; Sárossy, Zsuzsa; Pinelo, Manuel; Meyer, Anne S

    2017-12-01

    Enzymatic reduction of carbon dioxide (CO 2 ) to methanol (CH 3 OH) can be accomplished using a designed set-up of three oxidoreductases utilizing reduced pyridine nucleotide (NADH) as cofactor for the reducing equivalents electron supply. For this enzyme system to function efficiently a balanced regeneration of the reducing equivalents during reaction is required. Herein, we report the optimization of the enzymatic conversion of formaldehyde (CHOH) to CH 3 OH by alcohol dehydrogenase, the final step of the enzymatic redox reaction of CO 2 to CH 3 OH, with kinetically synchronous enzymatic cofactor regeneration using either glucose dehydrogenase (System I) or xylose dehydrogenase (System II). A mathematical model of the enzyme kinetics was employed to identify the best reaction set-up for attaining optimal cofactor recycling rate and enzyme utilization efficiency. Targeted process optimization experiments were conducted to verify the kinetically modeled results. Repetitive reaction cycles were shown to enhance the yield of CH 3 OH, increase the total turnover number (TTN) and the biocatalytic productivity rate (BPR) value for both system I and II whilst minimizing the exposure of the enzymes to high concentrations of CHOH. System II was found to be superior to System I with a yield of 8 mM CH 3 OH, a TTN of 160 and BPR of 24 μmol CH 3 OH/U · h during 6 hr of reaction. The study demonstrates that an optimal reaction set-up could be designed from rational kinetics modeling to maximize the yield of CH 3 OH, whilst simultaneously optimizing cofactor recycling and enzyme utilization efficiency. © 2017 Wiley Periodicals, Inc.

  5. Cellular mechanism underlying formaldehyde-stimulated Cl- secretion in rat airway epithelium.

    Directory of Open Access Journals (Sweden)

    Yu-Li Luo

    Full Text Available BACKGROUND: Recent studies suggest that formaldehyde (FA could be synthesized endogeneously and transient receptor potential (TRP channel might be the sensor of FA. However, the physiological significance is still unclear. METHODOLOGY/PRINCIPAL FINDINGS: The present study investigated the FA induced epithelial Cl(- secretion by activation of TRPV-1 channel located in the nerve ending fiber. Exogenously applied FA induced an increase of I(SC in intact rat trachea tissue but not in the primary cultured epithelial cells. Western blot and immunofluorescence analysis identified TRPV-1 expression in rat tracheal nerve ending. Capsazepine (CAZ, a TRPV-1 specific antagonist significantly blocked the I(SC induced by FA. The TRPV-1 agonist capsaicin (Cap induced an increase of I(SC, which was similar to the I(SC induced by FA. L-703606, an NK-1 specific inhibitor and propranolol, an adrenalin β receptor inhibitor significantly abolished the I(SC induced by FA or Cap. In the ion substitute analysis, FA could not induce I(SC in the absence of extracelluar Cl(-. The I(SC induced by FA could be blocked by the non-specific Cl(- channel inhibitor DPC and the CFTR specific inhibitor CFTR(i-172, but not by the Ca(2+-activated Cl(- channel inhibitor DIDS. Furthermore, both forskolin, an agonist of adenylate cyclase (AC and MDL-12330A, an antagonist of AC could block FA-induced I(SC. CONCLUSION: Our results suggest that FA-induced epithelial I(SC response is mediated by nerve, involving the activation of TRPV-1 and release of adrenalin as well as substance P.

  6. Gas-phase thermolysis reaction of formaldehyde diperoxide. Kinetic study and theoretical mechanisms

    International Nuclear Information System (INIS)

    Jorge, Nelly Lidia; Romero, Jorge Marcelo; Grand, André; Hernández-Laguna, Alfonso

    2012-01-01

    Highlights: ► Kinetic and mechanism of the gas-phase thermolysis of tetroxane were determined. ► Gas chromatography and computational potential energy surfaces were performed. ► A mechanism in steps looked like the most probable mechanism. ► A spin–orbit coupling appeared at the singlet and triple diradical open structures. ► A non-adiabatic crossing from the singlet to the triplet state occurred. - Abstract: Gas-phase thermolysis reaction of formaldehyde diperoxide (1,2,4,5-tetroxane) was performed in an injection chamber of a gas chromatograph at a range of 463–503 K. The average Arrhenius activation energy and pre-exponential factor were 29.3 ± 0.8 kcal/mol and 5.2 × 10 13 s −1 , respectively. Critical points and reaction paths of the ground singlet and first triplet potential energy surfaces (PES) were calculated, using DFT method at BHANDHLYP/6-311+G ∗∗ level of the theory. Also, G3 calculations were performed on the reactant and products. Reaction by the ground-singlet and first-triplet states turned out to be endothermic and exothermic, respectively. The mechanism in three steps seemed to be the most probable one. An electronically non-adiabatic process appeared, in which a crossing, at an open diradical structure, from the singlet to the triplet state PES occurred, due to a spin–orbit coupling, yielding an exothermic reaction. Theoretical kinetic constant coming from the non- adiabatic transition from the singlet to the triplet state agrees with the experimental values.

  7. Cell proliferation in rat nasal respiratory epithelium following three months exposure to formaldehyde gas

    International Nuclear Information System (INIS)

    Monticello, T.M.; Morgan, K.T.

    1990-01-01

    Formaldehyde (HCHO), a ubiquitous chemical and rat nasal carcinogen, enhances cell proliferation in rat, monkey, and xenotransplanted human respiratory epithelium following short-term exposure. The present studies were designed to evaluate cell proliferation in relation to tumor induction in rat nasal respiratory epithelium following subchronic HCHO exposure. Male F-344 rats were whole-body exposed to either 0, 0.7, 2, 6, 10, or 15 ppm HCHO, for wither 4 d (6hr/d), 6 wks (5d/wk) or 3 months. Animals were labeled with tritiated thymidine prior to euthanasia. Nasal sections were processed for autoradiography and cell proliferation data was expressed as unit length labeling indices (ULLI). HCHO-induced lesions and increases in cell proliferation occurred in specific regions of the nose, primarily the wall of the lateral meatus and nasal septum of the anterior nasal cavity. Following 4 d exposure, significant elevations in cell proliferation were observed only in the 6, 10 and 15 ppm groups (16-, 18-, and 20-fold increase over control, respectively). Increases in ULLI were also present in the 6, 10 and 15 ppm groups after 6 wks of exposure (12-, 35-, and 40-fold increase over control). However, after 3 months exposure, elevations in ULLI were present only in the 10 and 15 ppm groups (9- and 14-fold increase over controls). These results demonstrate that (1) low levels of HCHO (0.7 and 2 ppm) do not increase cell proliferation in rat nasal respiratory epithelium; (2) 6 ppm HCHO induces transient increases in cell proliferation; and (3) clearly carcinogenic concentrations of HCHO (10 and 15 ppm) cause sustained elevations in cell proliferation which may play an important role in HCHO-induced carcinogenesis

  8. Study on the pyrolysis of phenol-formaldehyde (PF) resin and modified PF resin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jigang, E-mail: wangjigang@seu.edu.cn [Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiang, Haiyun [Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); School of Materials Science and Engineering, Southeast University, Nanjing Institute of Technology, Nanjing 210013 (China); Jiang, Nan [Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210093 (China)

    2009-12-10

    The pyrolysis of pure phenol-formaldehyde (PF) resin and boron carbide (B{sub 4}C) modified PF resin was investigated by using thermogravimetry (TG) and pyrolysis gas-chromatography-mass-spectrometry (PY-GC/MS). Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy were also employed to investigate the micro-structural evolution. It was shown from the TG analysis that the char residues of pure PF resin were 62.9 and 60.5% after being pyrolyzed at 700 and 1000 {sup o}C, respectively. The degradation and failure of the resin matrix were mainly resulted from the release of volatiles. The phenol and its methyl derivates took a large proportion in the amount of volatiles. In comparison with the pure PF resin, the char residues of B{sub 4}C modified PF resin were obviously higher, with the values of 71.9 and 68.4% at 700 and 1000 {sup o}C, respectively. Due to the oxidation-reduction reactions between B{sub 4}C additive and oxygen-containing volatiles including CO and H{sub 2}O, partial carbon and oxygen elements in the volatiles remained in the resin matrix in the forms of amorphous carbon and B{sub 2}O{sub 3}, respectively. The results of SEM and FT-IR characterization demonstrated the occurrence of the modification, and the amorphous carbon existed in the form of reticular substance. In addition, the amount of the released phenol and its methyl derivates was also decreased drastically due to the formation of borate.

  9. Formaldehyde production from isoprene oxidation across NOx regimes

    Directory of Open Access Journals (Sweden)

    G. M. Wolfe

    2016-03-01

    Full Text Available The chemical link between isoprene and formaldehyde (HCHO is a strong, nonlinear function of NOx (i.e., NO + NO2. This relationship is a linchpin for top-down isoprene emission inventory verification from orbital HCHO column observations. It is also a benchmark for overall photochemical mechanism performance with regard to VOC oxidation. Using a comprehensive suite of airborne in situ observations over the southeast US, we quantify HCHO production across the urban–rural spectrum. Analysis of isoprene and its major first-generation oxidation products allows us to define both a "prompt" yield of HCHO (molecules of HCHO produced per molecule of freshly emitted isoprene and the background HCHO mixing ratio (from oxidation of longer-lived hydrocarbons. Over the range of observed NOx values (roughly 0.1–2 ppbv, the prompt yield increases by a factor of 3 (from 0.3 to 0.9 ppbv ppbv−1, while background HCHO increases by a factor of 2 (from 1.6 to 3.3 ppbv. We apply the same method to evaluate the performance of both a global chemical transport model (AM3 and a measurement-constrained 0-D steady-state box model. Both models reproduce the NOx dependence of the prompt HCHO yield, illustrating that models with updated isoprene oxidation mechanisms can adequately capture the link between HCHO and recent isoprene emissions. On the other hand, both models underestimate background HCHO mixing ratios, suggesting missing HCHO precursors, inadequate representation of later-generation isoprene degradation and/or underestimated hydroxyl radical concentrations. Detailed process rates from the box model simulation demonstrate a 3-fold increase in HCHO production across the range of observed NOx values, driven by a 100 % increase in OH and a 40 % increase in branching of organic peroxy radical reactions to produce HCHO.

  10. Toward an effective adsorbent for polar pollutants: Formaldehyde adsorption by activated carbon

    International Nuclear Information System (INIS)

    Lee, Kyung Jin; Miyawaki, Jin; Shiratori, Nanako; Yoon, Seong-Ho; Jang, Jyongsik

    2013-01-01

    Highlights: • Activated carbon fiber with mild activation condition is useful as adsorbent for polar pollutants. • Diverse variations are investigated for developing an effective adsorbent. • Surface functional group is the most important factor for capacity as a adsorbent. • Surface functional groups on ACFs are investigated using micro-ATR FTIR. -- Abstract: Due to increasing concerns about environmental pollutants, the development of an effective adsorbent or sensitive sensor has been pursued in recent years. Diverse porous materials have been selected as promising candidates for detecting and removing harmful materials, but the most appropriate pore structure and surface functional groups, both important factors for effective adsorbency, have not yet been fully elucidated. In particular, there is limited information relating to the use of activated carbon materials for effective adsorbent of specific pollutants. Here, the pore structure and surface functionality of polyacrylonitrile-based activated carbon fibers were investigated to develop an efficient adsorbent for polar pollutants. The effect of pore structure and surface functional groups on removal capability was investigated. The activated carbons with higher nitrogen content show a great ability to absorb formaldehyde because of their increased affinity with polar pollutants. In particular, nitrogen functional groups that neighbor oxygen atoms play an important role in maximizing adsorption capability. However, because there is also a similar increase in water affinity in adsorbents with polar functional groups, there is a considerable decrease in adsorption ability under humid conditions because of preferential adsorption of water to adsorbents. Therefore, it can be concluded that pore structures, surface functional groups and the water affinity of any adsorbent should be considered together to develop an effective and practical adsorbent for polar pollutants. These studies can provide vital

  11. MAX-DOAS formaldehyde slant column measurements during CINDI: intercomparison and analysis improvement

    Directory of Open Access Journals (Sweden)

    G. Pinardi

    2013-01-01

    Full Text Available We present intercomparison results for formaldehyde (HCHO slant column measurements performed during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI that took place in Cabauw, the Netherlands, in summer 2009. During two months, nine atmospheric research groups simultaneously operated MAX-DOAS (MultiAXis Differential Optical Absorption Spectroscopy instruments of various designs to record UV-visible spectra of scattered sunlight at different elevation angles that were analysed using common retrieval settings. The resulting HCHO data set was found to be highly consistent, the mean difference between instruments generally not exceeding 15% or 7.5 × 1015 molec cm−2, for all viewing elevation angles. Furthermore, a sensitivity analysis was performed to investigate the uncertainties in the HCHO slant column retrieval when varying key input parameters such as the molecular absorption cross sections, correction terms for the Ring effect or the width and position of the fitting interval. This study led to the identification of potentially important sources of errors associated with cross-correlation effects involving the Ring effect, O4, HCHO and BrO cross sections and the DOAS closure polynomial. As a result, a set of updated recommendations was formulated for HCHO slant column retrieval in the 336.5–359 nm wavelength range. To conclude, an error budget is proposed which distinguishes between systematic and random uncertainties. The total systematic error is estimated to be of the order of 20% and is dominated by uncertainties in absorption cross sections and related spectral cross-correlation effects. For a typical integration time of one minute, random uncertainties range between 5 and 30%, depending on the noise level of individual instruments.

  12. Uptake of gaseous formaldehyde onto soil surfaces: a coated-wall flow tube study

    Science.gov (United States)

    Li, Guo; Su, Hang; Li, Xin; Meusel, Hannah; Kuhn, Uwe; Pöschl, Ulrich; Shao, Min; Cheng, Yafang

    2015-04-01

    Gaseous formaldehyde (HCHO) is an important intermediate molecule and source of HO2 radicals. However, discrepancies exist between model simulated and observed HCHO concentrations, suggesting missing sources or sinks in the HCHO budget. Multiphase processes on the surface of soil and airborne soil-derived particles have been suggested as an important mechanism for the production/removal of atmospheric trace gases and aerosols. In this work, the uptake of gaseous HCHO on soil surfaces were investigated through coated-wall flow tube experiments with HCHO concentration ranging from 10 to 40 ppbv. The results show that the adsorption of HCHO occurred on soil surfaces, and the uptake coefficient dropped gradually (i.e., by a factor of 5 after 1 hour) as the reactive surface sites were consumed. The HCHO uptake coefficient was found to be affected by the relative humidity (RH), decreasing from (2.4 ± 0.5) × 10-4 at 0% RH to (3.0 ± 0.08) × 10-5 at 70% RH, due to competition of water molecule absorption on the soil surface. A release of HCHO from reacted soil was also detected by applying zero air, suggesting the nature of reversible physical absorption and the existence of an equilibrium at the soil-gas interface. It implies that soil could be either a source or a sink for HCHO, depending on the ambient HCHO concentration. We also develop a Matlab program to calculate the uptake coefficient under laminar flow conditions based on the Cooney-Kim-Davis method.

  13. Phenol-Formaldehyde Resin-Based Carbons for CO2 Separation at Sub-Atmospheric Pressures

    Directory of Open Access Journals (Sweden)

    Noelia Álvarez-Gutiérrez

    2016-03-01

    Full Text Available The challenge of developing effective separation and purification technologies that leave much smaller energy footprints is greater for carbon dioxide (CO2 than for other gases. In addition to its involvement in climate change, CO2 is present as an impurity in biogas and bio-hydrogen (biological production by dark fermentation, in post-combustion processes (flue gas, CO2-N2 and many other gas streams. Selected phenol-formaldehyde resin-based activated carbons prepared in our laboratory have been evaluated under static conditions (adsorption isotherms as potential adsorbents for CO2 separation at sub-atmospheric pressures, i.e., in post-combustion processes or from biogas and bio-hydrogen streams. CO2, H2, N2, and CH4 adsorption isotherms at 25 °C and up to 100 kPa were obtained using a volumetric equipment and were correlated by applying the Sips model. Adsorption equilibrium was then predicted for multicomponent gas mixtures by extending the multicomponent Sips model and the Ideal Adsorbed Solution Theory (IAST in conjunction with the Sips model. The CO2 uptakes of the resin-derived carbons from CO2-CH4, CO2-H2, and CO2-N2 at atmospheric pressure were greater than those of the reference commercial carbon (Calgon BPL. The performance of the resin-derived carbons in terms of equilibrium of adsorption seems therefore relevant to CO2 separation in post-combustion (flue gas, CO2-N2 and in hydrogen fermentation (CO2-H2, CO2-CH4.

  14. Synthesis, characterization and thermal analysis of urea-formaldehyde/nanoSiO{sub 2} resins

    Energy Technology Data Exchange (ETDEWEB)

    Roumeli, E. [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Papadopoulou, E. [Chimar Hellas S.A., Sofouli 88, 55131 Thessaloniki (Greece); Pavlidou, E.; Vourlias, G. [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Bikiaris, D. [Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Paraskevopoulos, K.M. [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Chrissafis, K., E-mail: hrisafis@physics.auth.gr [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer UF/nanosilica resins have been produced using the minimum cost method. Black-Right-Pointing-Pointer The new resins had good dispersion and enhanced properties. Black-Right-Pointing-Pointer Nanosilica interacts with polymer chains as was proved by FTIR and DSC. Black-Right-Pointing-Pointer Nanosilica does not affect the resin's thermal stability but enhances its mechanical properties. - Abstract: In the present work urea-formaldehyde resins (UF) containing different amounts of SiO{sub 2} nanoparticles were synthesized and studied in depth. All the hybrids were characterized with Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffractometry (XRD), while the dispersion of nanoparticles was studied with scanning electron microscopy with associated energy dispersive X-ray spectrometer (SEM/EDS). It was found that even though silanol groups of SiO{sub 2} can interact with UF resin and form hydrogen bonds, aggregates of SiO{sub 2} nanoparticles can still be formed in UF resin. Their size increases as SiO{sub 2} content is increased. The curing reactions were examined with differential scanning calorimetry (DSC) and it was revealed that curing temperature of UF resin is slightly affected by the addition of nanoparticles. Furthermore, the activation energy of the curing reactions, for every hybrid, was calculated using the Kissinger's method, which implied the existence of interactions between the nanoparticles and the polymer chain. Thermogravimetric analysis (TGA) revealed that SiO{sub 2} nanoparticles do not have an effect in the thermal stability of the resin. From the application of the prepared UF/SiO{sub 2} resins in wood panels it was found that the mechanical properties of the panels, like the internal bond and the modulus of rapture, are enhanced with increasing nanoSiO{sub 2} concentration.

  15. Ocular injury by transient formaldehyde exposure in a rabbit eye model.

    Directory of Open Access Journals (Sweden)

    Li-Ju Lai

    Full Text Available Formaldehyde (FA is frequently used in sterilizing surgical instruments and materials. Exposure to FA is highly concerned for eye tissues. Rabbit corneal epithelial cells were examined for changes after FA exposure. Our results showed that cell survival decreased 7 days after transient 3 min exposure to more than 100 ppm FA by trypan blue staining while MTT assay detected significant decrease at 20 ppm at 24 hours observation. The decrease of cell survival rate was concentration (up to 600 ppm- and observation time (1-7 day- dependent. The cell number decreased after 100 ppm FA exposure for more than 10 min at 7-day observation. The FA treated cells showed increased apoptosis/necrosis and cell cycle accumulation at sub G1 phase as well as mitochondria clustering around nucleus. The in vivo rabbit eye exposure for tear production by Schirmer's test revealed that the FA-induced overproduction of tear also exhibited observation time (1-10 day- and FA concentration (20-300 ppm for 5 min exposure-dependent. Activated extracellular signal-regulated kinase (pERK2 in cornea explants by western blotting was reduced and increased c-Jun amino - terminal kinase (JNK activation (pJNK in cornea and conjunctiva was evident at 2 month after exposure to 50-200 ppm FA for 5 min. In conclusion, injury to the eye with transient exposure of up to 100 ppm FA for 3 min decreased corneal cell survival while a more sensitive MTT test detected the cell decrease at 20 ppm FA exposure. Morphology changes can be observed even at 5 ppm FA exposure for 3 min at 7 days after. The FA exposure also increased apoptotic/necrotic cells and sub-G1 phase in cell cycle. Long term effect (2 months after exposure on the eye tissues even after the removal of FA can be observed with persistent JNK activation in cornea and conjunctiva.

  16. Comparisons of Box Model Calculations and Measurements of Formaldehyde from the 1997 North Atlantic Regional Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Frost, G. J.; Fried, Alan; Lee, Y.- N.; Wert, B.; Henry, B.; Drummond, J. R.; Evans, M. J.; Fehsenfeld, Fred C.; Goldan, P. D.; Holloway, J. S.; Hubler, Gerhard F.; Jakoubek, R.; Jobson, B Tom T.; Knapp, K.; Kuster, W. C.; Roberts, J.; Rudolph, Jochen; Ryerson, T. B.; Stohl, A.; Stroud, C.; Sueper, D. T.; Trainer, Michael; Williams, J.

    2002-04-18

    Formaldehyde (CH2O) measurements from two independent instruments are compared with photochemical box model calculations. The measurements were made on the National Oceanic and Atmospheric Administration P-3 aircraft as part of the 1997 North Atlantic Regional Experiment (NARE 97). The data set considered here consists of air masses sampled between 0 and 8 km over the North Atlantic Ocean which do not show recent influence from emissions or transport. These air masses therefore should be in photochemical steady state with respect to CH2O when constrained by the other P-3 measurements, and methane oxidation was expected to be the predominant source of CH2O in these air masses. For this data set both instruments measured identical CH2O concentrations to within 40 parts per trillion by volume (pptv) on average over the 0–800 pptv range, although differences larger than the combined 2s total uncertainty estimates were observed between the two instruments in 11% of the data. Both instruments produced higher CH2O concentrations than the model in more than 90% of this data set, with a median measured-modeled [CH2O] difference of 0.13 or 0.18 ppbv (depending on the instrument), or about a factor of 2. Such large differences cannot be accounted for by varying model input parameters within their respective uncertainty ranges. After examining the possible reasons for the model-measurement discrepancy, we conclude that there are probably one or more additional unknown sources of CH2O in the North Atlantic troposphere.

  17. Low Level Laser Therapy Reduces the Development of Lung Inflammation Induced by Formaldehyde Exposure.

    Directory of Open Access Journals (Sweden)

    Cristiane Miranda da Silva

    Full Text Available Lung diseases constitute an important public health problem and its growing level of concern has led to efforts for the development of new therapies, particularly for the control of lung inflammation. Low Level Laser Therapy (LLLT has been highlighted as a non-invasive therapy with few side effects, but its mechanisms need to be better understood and explored. Considering that pollution causes several harmful effects on human health, including lung inflammation, in this study, we have used formaldehyde (FA, an environmental and occupational pollutant, for the induction of neutrophilic lung inflammation. Our objective was to investigate the local and systemic effects of LLLT after FA exposure. Male Wistar rats were exposed to FA (1% or vehicle (distillated water during 3 consecutive days and treated or not with LLLT (1 and 5 hours after each FA exposure. Non-manipulated rats were used as control. 24 h after the last FA exposure, we analyzed the local and systemic effects of LLLT. The treatment with LLLT reduced the development of neutrophilic lung inflammation induced by FA, as observed by the reduced number of leukocytes, mast cells degranulated, and a decreased myeloperoxidase activity in the lung. Moreover, LLLT also reduced the microvascular lung permeability in the parenchyma and the intrapulmonary bronchi. Alterations on the profile of inflammatory cytokines were evidenced by the reduced levels of IL-6 and TNF-α and the elevated levels of IL-10 in the lung. Together, our results showed that LLLT abolishes FA-induced neutrophilic lung inflammation by a reduction of the inflammatory cytokines and mast cell degranulation. This study may provide important information about the mechanisms of LLLT in lung inflammation induced by a pollutant.

  18. The Antioxidant Cofactor Alpha-Lipoic Acid May Control Endogenous Formaldehyde Metabolism in Mammals

    Directory of Open Access Journals (Sweden)

    Anastasia V. Shindyapina

    2017-12-01

    Full Text Available The healthy human body contains small amounts of metabolic formaldehyde (FA that mainly results from methanol oxidation by pectin methylesterase, which is active in a vegetable diet and in the gastrointestinal microbiome. With age, the ability to maintain a low level of FA decreases, which increases the risk of Alzheimer's disease and dementia. It has been shown that 1,2-dithiolane-3-pentanoic acid or alpha lipoic acid (ALA, a naturally occurring dithiol and antioxidant cofactor of mitochondrial α-ketoacid dehydrogenases, increases glutathione (GSH content and FA metabolism by mitochondrial aldehyde dehydrogenase 2 (ALDH2 thus manifests a therapeutic potential beyond its antioxidant property. We suggested that ALA can contribute to a decrease in the FA content of mammals by acting on ALDH2 expression. To test this assumption, we administered ALA in mice in order to examine the effect on FA metabolism and collected blood samples for the measurement of FA. Our data revealed that ALA efficiently eliminated FA in mice. Without affecting the specific activity of FA-metabolizing enzymes (ADH1, ALDH2, and ADH5, ALA increased the GSH content in the brain and up-regulated the expression of the FA-metabolizing ALDH2 gene in the brain, particularly in the hippocampus, but did not impact its expression in the liver in vivo or in rat liver isolated from the rest of the body. After ALA administration in mice and in accordance with the increased content of brain ALDH2 mRNA, we detected increased ALDH2 activity in brain homogenates. We hypothesized that the beneficial effects of ALA on patients with Alzheimer's disease may be associated with accelerated ALDH2-mediated FA detoxification and clearance.

  19. Mixture Design Approach on the Physical Properties of Lignin-Resorcinol-Formaldehyde Xerogels

    Directory of Open Access Journals (Sweden)

    Chris D. Castro

    2015-01-01

    Full Text Available Organic xerogels were functionalized by incorporating sugarcane bagasse lignin from soda pulping black liquor, not used so far in this materials, with the aim of introducing new functional groups on traditional gels that could improve its adsorptive capacity. Two mixing designs were applied to identify the reactive combinations that allow a well gel formation and to adjust models that predict physical properties. The designs study five components: resorcinol (R, 0.04–0.3, lignin (L, 0.004–0.14, formaldehyde (F, 0.08–0.17, water (W, 0.45–0.8, and NaOH (C, 0.0003–0.0035. The first experimental design was an extreme vertices design and its results showed shrinkage between 4.3 and 59.7 and a bulk density from 0.54 to 1.3; a mass ratio LR/F near 1.5 was required for gel formation. In the second design a D-Optimal was used to achieve better adjusted coefficients and incorporate the largest possible amount of lignin in the gels. Bulk density varies from 0.42 to 0.9, shrinkage varies from 3.42 to 25.35, and specific surface area reaches values of 451.86 m2/g with 13% lignin and 270 m2/g with 27% lignin. High catalyst content improves lignin dissolution and increase shrinkage and bulk density of xerogels and bulk density. Lignin contributes to reducing shrinkage and specific surface area due to his compact and rigid structure.

  20. Morphologic observations on respiratory tracts of chickens after hatchery infectious bronchitis vaccination and formaldehyde fumigation.

    Science.gov (United States)

    Di Matteo, A M; Soñez, M C; Plano, C M; von Lawzewitsch, I

    2000-01-01

    The histologic changes in the respiratory tracts of chickens were evaluated after hatchery fumigation with 40% formaldehyde vapors and vaccination against infectious bronchitis virus with live attenuated vaccine (Massachusetts serotype). One-day-old chickens were housed in four isolation units in controlled environmental conditions, fed and watered ad libitum, and separated into four groups: 1) fumigated and vaccinated birds (FV group); 2) nonfumigated and vaccinated birds (NFV group); 3) fumigated and nonvaccinated birds (FNV group); and 4) control group (C group). All birds were tested to be free from Mycoplasma gallisepticum and Mycoplasma synoviae. After necropsy on the first, eighth, and twenty-sixth days after birth, samples from tracheal upper portion and lungs were conventionally processed for light, scanning, and transmission electron microscopy. Tissue response was monitored by microscopic examination of trachea and lung. On the first day of observation, fumigated and vaccinated birds (FV group) showed extensively damaged tracheal epithelium with exfoliated areas and some active glands with electrodense granules, and in the lung, the primary bronchi epithelium had disorganized cilia and abundant lymphocytes, with emphysematous areas in tertiary bronchus. On day 8 after vaccination, cubical and cylindrical tracheal cell proliferation was observed, and on day 26, ciliated columnar epithelium was almost regenerated with heterophil corion infiltration, and hyaline cartilage nodules appeared in parabronchi. The nonfumigated and vaccinated birds (NFV) revealed less injury on the epithelial surface and a more rapid response to epithelial regeneration than the in only fumigated animals (FNV). The control group did not show remarkable morphologic changes. Postvaccinal and fumigation effects on the upper respiratory tract were temporary, whereas in lungs, increased emphysema, cartilage nodules in the interchange zone, and general lymphocyte infiltration had caused

  1. Formaldehyde exposure and lower respiratory infections in infants: findings from the PARIS cohort study.

    Science.gov (United States)

    Roda, Célina; Kousignian, Isabelle; Guihenneuc-Jouyaux, Chantal; Dassonville, Claire; Nicolis, Ioannis; Just, Jocelyne; Momas, Isabelle

    2011-11-01

    Certain chemical pollutants can exacerbate lower respiratory tract infections (LRIs), a common childhood ailment. Although formaldehyde (FA) is one of the most common air pollutants found in indoor environments, its impact on infant health is uncertain. Our aim was to determine the impact of FA exposure on the LRI incidence during the first year of life of infants from the Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort. FA was measured in a random sample of 196 infants' dwellings, and exposure to this pollutant was estimated for 2,940 infants using predictive models based on measurements and data about potential determinants of FA levels. Health data were collected from parents by regular self-administered questionnaires. We used multivariate logistic regressions to estimate associations between FA exposure and the occurrence of LRI and wheezy LRI (wLRI), adjusting for potential confounders/risk factors. During the first year of life, 45.8% of infants had at least one LRI, and LRI occurred simultaneously with wheezing in 48.7% of cases. The FA predictive models correctly classified 70% of dwellings as having high or low exposure, and we estimated that 43.3% of infants were exposed throughout the first year to levels of FA > 19.5 µg/m3. FA exposure was significantly associated with LRI and wLRI before and after adjustment for known LRI risk factors/confounders. For an interquartile increase in FA levels (12.4 μg/m3), we estimated a 32% [95% confidence interval (CI): 11, 55] and 41% (95% CI: 14, 74) increase in the incidence of LRI and wLRI, respectively. The findings of this study suggest that infants exposed to FA at an early age have an increased incidence of LRI.

  2. Quantitative analysis of histone modifications: formaldehyde is a source of pathological n(6-formyllysine that is refractory to histone deacetylases.

    Directory of Open Access Journals (Sweden)

    Bahar Edrissi

    Full Text Available Aberrant protein modifications play an important role in the pathophysiology of many human diseases, in terms of both dysfunction of physiological modifications and the formation of pathological modifications by reaction of proteins with endogenous electrophiles. Recent studies have identified a chemical homolog of lysine acetylation, N(6-formyllysine, as an abundant modification of histone and chromatin proteins, one possible source of which is the reaction of lysine with 3'-formylphosphate residues from DNA oxidation. Using a new liquid chromatography-coupled to tandem mass spectrometry method to quantify all N(6-methyl-, -acetyl- and -formyl-lysine modifications, we now report that endogenous formaldehyde is a major source of N(6-formyllysine and that this adduct is widespread among cellular proteins in all compartments. N(6-formyllysine was evenly distributed among different classes of histone proteins from human TK6 cells at 1-4 modifications per 10(4 lysines, which contrasted strongly with lysine acetylation and mono-, di-, and tri-methylation levels of 1.5-380, 5-870, 0-1400, and 0-390 per 10(4 lysines, respectively. While isotope labeling studies revealed that lysine demethylation is not a source of N(6-formyllysine in histones, formaldehyde exposure was observed to cause a dose-dependent increase in N(6-formyllysine, with use of [(13C,(2H2]-formaldehyde revealing unchanged levels of adducts derived from endogenous sources. Inhibitors of class I and class II histone deacetylases did not affect the levels of N(6-formyllysine in TK6 cells, and the class III histone deacetylase, SIRT1, had minimal activity (<10% with a peptide substrate containing the formyl adduct. These data suggest that N(6-formyllysine is refractory to removal by histone deacetylases, which supports the idea that this abundant protein modification could interfere with normal regulation of gene expression if it arises at conserved sites of physiological protein secondary

  3. Beyond SHARP-- Primary Formaldehyde from Oil and Gas Exploration and Production in the Gulf of Mexico Region

    Science.gov (United States)

    Olaguer, E. P.

    2010-12-01

    Formaldehyde has been named by the EPA as a hazardous air pollutant that may be carcinogenic and also cause irritation to the eyes, nose, throat and lung. Moreover, it is a powerful radical and ozone precursor. The 2009 Study of Houston Atmospheric Radical Precursors (SHARP) was conceived by the Houston Advanced Research Center (HARC) on behalf of the Texas Environmental Research Consortium (TERC) to examine the relative importance of primary and secondary formaldehyde (HCHO) and nitrous acid (HONO) in ozone formation. SHARP confirmed that primary combustion sources of HCHO, such as flares end engines, may be underestimated (by an order of magnitude or more) in official emission inventories used for the purpose of air quality modeling in highly industrialized areas such as Houston. This presentation provides recently generated modeling and observational evidence that the same may be true in both rural and urban areas with oil and gas exploration and production (E&P) activities, such as the Upper Green River Basin of Wyoming and the Barnett Shale of Texas. Oil and gas E&P is increasing in the Gulf of Mexico region, particularly in the Barnett, Haynesville, Eagle Ford, Cana-Woodford, and Fayetteville shale basins. In the Barnett Shale, E&P activities are moving into urban neighborhoods, and may affect the ability to bring the Dallas-Ft. Worth region into attainment of the federal ozone standard. Data concerning formaldehyde emissions from drill rig and pipeline compressor engines, flares, and glycol or amine reboilers, should be obtained in order to more accurately model air quality in the Gulf of Mexico region.

  4. Bio-template-assisted synthesis of hierarchically hollow SiO2 microtubes and their enhanced formaldehyde adsorption performance

    International Nuclear Information System (INIS)

    Le, Yao; Guo, Daipeng; Cheng, Bei; Yu, Jiaguo

    2013-01-01

    The indoor air quality is crucial for human health, taking into account that people often spend more than 80% of their time in houses, offices and cars. Formaldehyde (HCHO) is a major pollutant and long-term exposure to HCHO may cause health problems such as nasal tumors and skin irritation. In this work, for the first time, hierarchically hollow silica microtubes (HHSM) were synthesized by a simple sol–gel and calcination method using cetyltrimethyl ammonium bromide (CTAB) and bio-template poplar catkin (PC) as co-templates and the PC/SiO 2 weight ratio R was varied from 0, 0.1, 0.3 and 1. The prepared samples were further modified with tetraethylenepentamine (TEPA) and characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), differential thermal analysis (DTA), thermal gravimetric analysis (TGA), and N 2 physisorption techniques. This was followed by formaldehyde adsorption tests at ambient temperature. The results showed that all the prepared HHSM samples contained small mesopores with peak pore size at ca. 2.5 nm and large several tens of nanometer-sized pores on the tube wall. The R exhibited an obvious influence on specific surface areas and the sample prepared at R = 0.3 exhibited highest specific surface area (896 m 2 /g). All the TEPA-modified samples exhibited enhanced formaldehyde adsorption performance. The maximum HCHO adsorption capacity (20.65 mg/g adsorbent) was achieved on the sample prepared at R = 0.3 and modified by 50 wt.% TEPA. The present study will provide new insight for the utilization of bio-template used for the fabrication of inorganic hollow tubes with high HCHO adsorption performance for indoor air purification.

  5. An Assessment of Urea-Formaldehyde Fertilizer on the Diversity of Bacterial Communities in Onion and Sugar Beet

    OpenAIRE

    Ikeda, Seishi; Suzuki, Keijiro; Kawahara, Makoto; Noshiro, Masao; Takahashi, Naokazu

    2014-01-01

    The impact of a urea-formaldehyde (UF) fertilizer on bacterial diversity in onion bulbs and main roots of sugar beet were examined using a 16S rRNA gene clone library. The UF fertilizer markedly increased bacterial diversity in both plants. The results of principal coordinates analysis (PCoA) revealed that nearly 30% of the variance observed in bacterial diversity in both the onion and sugar beet was attributed to the fertilization conditions and also that the community structures in both pla...

  6. Chemical derivation to enhance the chemical/oxidative stability of resorcinol-formaldehyde (R-F) resin

    International Nuclear Information System (INIS)

    Hubler, T.L.; Shaw, W.J.; Brown, G.N.; Linehan, J.C.; Franz, J.A.; Hart, T.R.; Hogan, M.O.

    1996-09-01

    Tank wastes at Hanford and SRS contain highly alkaline supernate solutions of conc. Na, K nitrates with large amounts of 137 Cs. It is desirable to remove and concentrate the highly radioactive fraction for vitrification. One candidate ion exchange material for removing the radiocesium is R-F resin. This report summarizes studies into synthesis and characterization of 4-derivatized R-F resins prepared in pursuit of more chemically/oxidatively robust resin. 85% 4-fluororesorcinol/15% phenol formaldehyde resin appears to have good stability in alkaline solution, although there may be some nucleophilic displacement reaction during synthesis; further studies are needed

  7. Sol-gel synthesis of iron catalysers supported on silica and titanium for selectively oxidising methane to formaldehyde

    OpenAIRE

    Carlos Alberto Guerrero Fajardo; Francisco José Sánchez Castellanos; Anne Cécile Roger; Claire Courson

    2010-01-01

    Iron materials supported on silica were prepared by the sol-gel method for evaluating catalytic activity in selective o-xidation of methane to formaldehyde. Four catalysts were prepared, one corresponding to the silica support (catalyst 1S), another to the titanium support (catalyst 1T) and two more having 0.5% weight iron loads, one for the silica su-pport (catalyst 2FS) and the last one the titanium support (catalyst 2FT). The higher BET areas were 659 and 850 m2/g for catalysts 1S and 2FS,...

  8. Preliminary flowsheet: Ion exchange for separation of cesium from Hanford tank waste using resorcinol-formaldehyde resin

    International Nuclear Information System (INIS)

    Penwell, D.L.

    1994-01-01

    This preliminary flowsheet document describes an ion exchange process which uses resorcinol-formaldehyde (R-F) resin to remove cesium from Hanford tank waste. The flowsheet describes one possible equipment configuration, and contains mass balances based on that configuration with feeds of Neutralized Current Acid Waste, and Double Shell Slurry Feed. The flowsheet also discusses process alternatives, unresolved issues, and development needs associated with the ion exchange process. It is expected that this flowsheet will evolve as open issues are resolved and progress is made on development needs. This is part of the Tank Waste Remediation Program at Hanford. 26 refs, 6 figs, 25 tabs

  9. 'Real-world' compensatory behaviour with low nicotine concentration e-liquid: subjective effects and nicotine, acrolein and formaldehyde exposure.

    Science.gov (United States)

    Dawkins, Lynne; Cox, Sharon; Goniewicz, Maciej; McRobbie, Hayden; Kimber, Catherine; Doig, Mira; Kośmider, Leon

    2018-06-07

    To compare the effects of i) high versus low nicotine concentration e-liquid, ii) fixed versus adjustable power and iii) the interaction between the two on: a) vaping behaviour, b) subjective effects, c) nicotine intake, and d) exposure to acrolein and formaldehyde in e-cigarette users vaping in their everyday setting. Counterbalanced, repeated measures with four conditions: i) low nicotine (6 mg/mL)/fixed power; ii) low nicotine/adjustable power; iii) high nicotine (18 mg/mL)/fixed power; iv) high nicotine/adjustable power. London and the South East, England. Twenty experienced e-cigarette users (recruited between September 2016 and February 2017) vaped ad libitum using an eVic Supreme™ with a 'Nautilus Aspire' tank over four weeks (one week per condition). Puffing patterns (daily puff number [PN], puff duration [PD], inter-puff interval [IPI]), mL of e-liquid consumed, changes to power (where permitted), and subjective effects (urge to vape, nicotine withdrawal symptoms) were measured in each condition. Nicotine intake was measured via salivary cotinine. 3-hydroxypropylmercapturic acid (3-HPMA), a metabolite of the toxicant acrolein, and formate, a metabolite of the carcinogen formaldehyde, were measured in urine. There was a significant nicotine concentration x power interaction for PD (p<0.01). PD was longer with low nicotine/fixed power compared with i) high nicotine/fixed power (p< 0.001 and ii) low nicotine/adjustable power (p< 0.01). PN and liquid consumed were higher in the low versus high nicotine condition (main effect of nicotine, p<0.05). Urge to vape and withdrawal symptoms were lower, and nicotine intake was higher, in the high nicotine condition (main effects of nicotine: p<0.01). Whilst acrolein levels did not differ, there was a significant nicotine x power interaction for formaldehyde (p<0.05). Use of a lower nicotine concentration e-liquid may be associated with compensatory behaviour (e.g., higher number and duration of puffs) and increases

  10. The influence of the diluent nature on scandium extraction by the phenol-formaldehyde resol oligomer yarrezin B

    International Nuclear Information System (INIS)

    Semenov, S.A.; Valkina, E.M.; Reznik, A.M.

    1996-01-01

    The paper studies the effect of diluent nature on scandium extraction by Yarrezin B phenol-formaldehyde resol oligomer using n-octan, toluene, chloroform, n-octanol and kerosene as an example. Correlation coefficients of dependences of scandium distribution factor on some parameters of diluents are calculated. Possibility to use some parameters of diluents to predict their effect on extraction indices is determined. Hildebrandt solubility parameter of extracting agent and parameters of extracting agent-diluent interaction according to Flory-Haggins are calculated. 13 refs., 2 figs., 4 tabs

  11. Infrared fluorescence efficiencies for the nu1 and nu5 bands of formaldehyde in the solar radiation field

    Science.gov (United States)

    Reuter, D. C.; Mumma, M. J.; Nadler, S.

    1989-01-01

    Formaldehyde scattering strengths have been determined for equilibrium distributions of 100 K, 50 K, 20 K, and for the the non-LTE case of an essentially fully relaxed distribution. Integrated band g factors of 2.89 x 10 to the -4th photons/s per molecule for nu1 and 3.83 x 10 to the -4th for nu 5 are obtained. The results indicate that the most promising regions to search for cometary H2CO are at about 2782/cm, at 2794.5/cm, and at about 2835/cm.

  12. [Microbial resistance to formaldehyde. I. Comparative quantitative studies in some selected species of vegetative bacteria, bacterial spores, fungi, bacteriophages and viruses].

    Science.gov (United States)

    Spicher, G; Peters, J

    1976-12-01

    The resistence of different microorganisms to formaldehyde was determined. As test objects served gram-negative and gram-positive vegetative germs (Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella paratyphi-B, Staphylococcus aureus, Streptococcus faecalis), bacterial spores (Bacillus cereus, Bacillus pumilus, Bacillus stearothermophilus, Bacillus subtilis), fungi (Aspergillus niger, Candida albicans), bacteriophages (Escherichia coli phages, T1, T2, T3), and viruses (adenovirus, poliomyelitis virus, vaccinia virus). For the studies, suspensions of germs were exposed at identical temperature (20 degrees C) and pH (7.0). The microbicidal effect of formaldehyde was measured by the decrease of the proportion of germs capable of multiplication in the suspension (lg (N/N0); where: N0 equals initial number of germs capable of multiplication; N equals number of germs capable of multiplication after exposure to formaldehyde). For all germs the dependence of the microbicidal effect on the concentration of formaldehyde was determined. In all experiments, the duration of exposure was two hours. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella paratyphi-B were found to be more susceptible than Staphylococcus aureus (vf. Fig. 1 A). The strains of Pseudomonas aeruginosa used were widely varying as to their susceptibility. To obtain equal microbicidal effects, concentrations of formaldehyde almost three times as high had to be used for the most resistant strain than were necessary for the most susceptible strain of Pseudomonas aeruginosa. All strains of Klebsiella pneumoniae examined were found to have an identical resistence to formaldehyde. Streptococcus faecalis was even more resistant to formaldehyde than Staphylococcus aureus. In the case of Streptococcus faecalis, a concentration of formaldehyde about three times as high had to be used to obtain microbicidal effects of identical magnitude. For the killing of Candida albicans cells concentrations of

  13. The electro-oxidation of the mixture of formaldehyde and 2-propanol on gold (100 and (111 single crystal planes in alkaline medium

    Directory of Open Access Journals (Sweden)

    BRANISLAV Z. NIKOLIC

    2000-12-01

    Full Text Available The effect of formaldehyde on the oxidation of 2-propanol and vice versa on gold single crystal planes (100 and 111 was studied. An activating effect in the reaction of the simultaneous oxidation of 2-propanol and formaldehyde was obtained on a gold (100 plane. In the case of a gold (111 electrode, the activation effect was not obtained. It was concluded that the adsorption of formaldehyde on the electrode surface prevents the adsorption of poisoning species formed during the electro-oxidation of 2-propanol on the Au(100 plane, while this is not the case on the Au(111 plane. The different behaviour is caused by the difference in the symmetry of the surface atoms of these two Au single-crystal planes.

  14. KASUS DISTRIBUSI DAN PENGGUNAAN FORMALIN DALAM PENGAWETAN KOMODITI IKAN LAUT SEGAR (STUDI KASUS DI KOTA BANDAR LAMPUNG [Formaldehyde Distribution and Using for Preserving Fresh Fish (A Case Study in Bandar Lampung City

    Directory of Open Access Journals (Sweden)

    Dias Yusdianson Girsang

    2014-12-01

    Full Text Available The purpose of this study was to identify the presence of formaldehyde in some fresh fish commodities and to trace formaldehyde distribution in Bandar Lampung City. The  formadelhyde tests were done  on the storage water of fresh fish samples. The study conducted in July to October 2013 was devided in two stages: a survey to fill out a questionnaire to a number of respondents, followed by sampling some storage water of fresh fish to be tested in the laboratory.  The tests were  carried out on 52 sampling points taken from the fishing boats in the fishing landing port (17 boats, fish supplier car from outside Bandar Lampung (6 cars as well as some fish sellers in 5 traditional market in Bandar Lampung (29 sellers. By conducting a laboratory test using Formaldehyde Test Kit, there were 2 samples that were purple (positively contain formaldehyde, which were taken from 2 boats in fish landing port of Lempasing. Then the assertion test was carried out to the positive samples using chromotropic acid (SNI 01 – 2894 – 1992. The results showed that the samples positively contained formaldehyde indeed, which was characterized by a bluish purple color. Based on the survey results and tracking, there was a distortion of formaldehyde distribution in Bandar Lampung, where domestic industries (including fisherman obtained formaldehyde illegally, either from End Users, a local manufacturer or drugstore/hospital/other health care facilities. Keywords: formaldehyde, fresh fish storage water, distribution distortion.

  15. KASUS DISTRIBUSI DAN PENGGUNAAN FORMALIN DALAM PENGAWETAN KOMODITI IKAN LAUT SEGAR (STUDI KASUS DI KOTA BANDAR LAMPUNG Formaldehyde Distribution and Using for Preserving Fresh Fish (A Case Study in Bandar Lampung City

    Directory of Open Access Journals (Sweden)

    Dias Yusdianson Girsang

    2014-12-01

    Full Text Available The purpose of this study was to identify the presence of formaldehyde in some fresh fish commodities and to trace formaldehyde distribution in Bandar Lampung City. The  formadelhyde tests were done  on the storage water of fresh fish samples. The study conducted in July to October 2013 was devided in two stages: a survey to fill out a questionnaire to a number of respondents, followed by sampling some storage water of fresh fish to be tested in the laboratory.  The tests were  carried out on 52 sampling points taken from the fishing boats in the fishing landing port (17 boats, fish supplier car from outside Bandar Lampung (6 cars as well as some fish sellers in 5 traditional market in Bandar Lampung (29 sellers. By conducting a laboratory test using Formaldehyde Test Kit, there were 2 samples that were purple (positively contain formaldehyde, which were taken from 2 boats in fish landing port of Lempasing. Then the assertion test was carried out to the positive samples using chromotropic acid (SNI 01 – 2894 – 1992. The results showed that the samples positively contained formaldehyde indeed, which was characterized by a bluish purple color. Based on the survey results and tracking, there was a distortion of formaldehyde distribution in Bandar Lampung, where domestic industries (including fisherman obtained formaldehyde illegally, either from End Users, a local manufacturer or drugstore/hospital/other health care facilities. Key word: formaldehyde, fresh fish storage water, distribution distortion.

  16. Air formaldehyde and solvent concentrations during surface coating with acid-curing lacquers and paints in the woodworking and furniture industry.

    Science.gov (United States)

    Thorud, Syvert; Gjolstad, Merete; Ellingsen, Dag G; Molander, Paal

    2005-06-01

    An investigation of contemporary exposure to formaldehyde and organic solvents has been carried out during surface coating with acid-curing lacquers and paints in the Norwegian woodworking and furniture industry over a period of 3 years. The investigation covered 27 factories of different sizes and with different types of production, and totally 557 parallel formaldehyde and solvent samples were collected. The formaldehyde concentration (geometric mean) was 0.15 ppm (range 0.01-1.48 ppm) with about 10% of the samples exceeding the Norwegian occupational exposure limit of 0.5 ppm. The solvent concentration as additive effect (geometric mean) was 0.13 (range 0.0004-5.08) and about 5% of the samples exceeded the Norwegian occupational exposure limit. The most frequently occurring solvents from acid-curing lacquers were n-butyl acetate, ethanol, ethyl acetate and 1-butanol, which were found in 88-98% of the samples. Toluene, n-butyl acetate and 1-butanol were the only solvents with maximum concentrations exceeding their respective occupational exposure limits. Curtain painting machine operators were exposed to the highest concentrations of both formaldehyde (geometric mean 0.51 ppm, range 0.08-1.48 ppm) and organic solvents (additive effect, geometric mean 1.18, range 0.02-5.08). Other painting application work tasks such as automatic and manual spray-painting, manual painting and dip painting, showed on average considerably lower concentrations of both formaldehyde (geometric means 0.07-0.16 ppm) and organic solvents (additive effect, geometric mean 0.02-0.18). Non-painting work tasks also displayed moderate concentrations of formaldehyde (geometric means 0.11-0.17 ppm) and organic solvents (additive effect, geometric mean 0.04-0.07).

  17. Multi-year MAX-DOAS observations of formaldehyde and glyoxal in Phimai, Thailand

    Science.gov (United States)

    Hoque, H. M. S.; Irie, H.; Shimizu, A.; Damiani, A.

    2017-12-01

    The first long-term Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations were performed in Phimai, Thailand (15.18 °N, 102.56 °E), a site in Southeast Asia, where ground-based remote sensing observations of trace gases and aerosols are very limited. Vertical profile information of eight components was retrieved independently using the Japanese MAX-DOAS profile retrieval algorithm, version 2 (JM2). Here we focus on the two organic compounds, formaldehyde (HCHO) and glyoxal (CHOCHO), and study their volume mixing ratio data in the lowest layer (0-1 km) of our retrieved vertical profiles. In addition to the systematic climatological analysis of HCHO and CHOCHO, we also report the ratio of CHOCHO to HCHO, RGF, which is suggested to be an important tracer of changes of the volatile organic compound (VOC) emission sources. Higher concentration of HCHO and CHOCHO was observed during the dry season (January-April), whereas the concentration level was close to the background level during the wet season (June-September). Such enhancements correspond well the influence of the pronounced seasonal variation of biomass burning activity. The RGF for the Phimai site was estimated to be 0.030±0.010. Our estimated RGF during the dry season ( 0.025±0.008) was lower than that in the wet season ( 0.033±0.012). This change in the RGF is consistent with the satellite retrievals, suggesting a higher RGF for strong biogenic emission sources. While the site can be characterized as environment with a low nitrogen dioxide (NO2) concentration level ( 1 ppbv), the impact of biomass burning on the lower RGF during the dry season was confirmed by occasional enhancement of the NO2 level as an anthropogenic tracer. The results are further supported by additional error analyses for the cloud influence. Our findings are expected to be used to reduce model uncertainties related to VOC chemistry and secondary organic aerosol (SOA) formation

  18. Hydraulic Permeability of Resorcinol-Formaldehyde Ion-Exchange Resin - Effects of Oxygen Uptake and Radiation

    International Nuclear Information System (INIS)

    Taylor, Paul Allen

    2009-01-01

    An ion-exchange process, using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the U.S. Department of Energy's (DOE) Hanford site in Washington State. The RF resin is also being evaluated for use in the proposed Small Column Ion Exchange (SCIX) system, which is an alternative treatment option at DOE's Savannah River Site (SRS)in South Carolina. Testing at ORNL will determine the impact of radiation exposure and oxygen uptake by the RF resin on the hydraulic permeability of the resin. Samples of the resin will be removed periodically to measure physical properties (bead size and compressibility) and cesium capacity. The proposed full-scale treatment system at Hanford, the Waste Treatment Plant (WTP), will use an ion-exchange column containing nominally 680 gal of resin, which will treat 30 gpm of waste solution. The ion-exchange column is designed for a typical pressure drop of 6 psig, with a maximum of 9.7 psig. The lab-scale column is 3-in. clear PVC pipe and is prototypic of the proposed Hanford column. The fluid velocity in the lab-scale test will be much higher than for the full-scale column, in order to generate the maximum pressure drop expected in that column (9.7 psig). The frictional drag from this high velocity will produce similar forces on the resin in the lab-scale column as would be expected at the bottom of the full-scale column. The chemical changes in the resin caused by radiation exposure and oxygen uptake are expected to cause physical changes in the resin that could reduce the bed porosity and reduce the hydraulic permeability of the resin bed. These changes will be monitored by measuring the pressure drop through the lab-scale column and by measuring the physical properties of samples of the resin. The test loop with the lab-scale column is currently being fabricated, and operation will start by late May. Testing will be completed by the

  19. Variations and sources of ambient formaldehyde for the 2008 Beijing Olympic games

    Science.gov (United States)

    Li, Yang; Shao, Min; Lu, Sihua; Chang, Chih-Chung; Dasgupta, Purnendu K.

    2010-07-01

    As the host city of the 2008 Olympic games, Beijing implemented a series of air pollution control measures before and during the Olympic games. Ambient formaldehyde (HCHO) concentrations were measured using a fluorometric instrument based on a diffusion scrubber and the Hantzsch reaction; hydrocarbons were simultaneously measured using gas chromatography-mass spectrometry (GC-MS). Meteorological parameters, CO, O 3, and NO 2 concentrations were measured by standard commercial instrumentation. In four separate periods: (a) before the vehicle plate number control (3-19 July); (b) during the Olympic Games (8-24 August); (c) during the Paralympic Games (6-17 September) and (d) after the vehicle control was ceased (21-28 September), the average HCHO mixing ratios were 7.31 ± 2.67 ppbv, 5.54 ± 2.41 ppbv, 8.72 ± 2.48 ppbv, and 6.42 ± 2.79 ppbv, while the total non-methane hydrocarbons (NMHCs) measured were 30.41 ± 18.08 ppbv, 18.12 ± 9.38 ppbv, 30.50 ± 13.37 ppbv, and 33.33 ± 15.85 ppbv, respectively. Both HCHO and NMHC levels were the lowest during the Olympic games, and increased again during the Paralympic games even with the same vehicle control measures operative. Similar diurnal HCHO and O 3 patterns indicated that photo-oxidation of NMHCs may be the major source of HCHO. The diurnal profile of total NMHCs was very similar to that of NO 2 and CO: morning and evening peaks appeared in rush hours, indicating even after strict vehicle control, automobile emission may still be the dominant source of the HCHO precursors. The contributions of HCHO, alkanes, alkenes, and aromatics to OH loss rates were also calculated. HCHO contributed 22 ± 3% to the total VOCs and 24 ± 1% to the total OH loss rate. HCHO was not only important in term of abundance, but also important in chemical reactivity in the air.

  20. Acidosis and Formaldehyde Secretion as a Possible Pathway of Cancer Pain and Options for Improved Cancer Pain Control.

    Science.gov (United States)

    Hoang, Ba X; Shaw, D Graeme; Han, Bo; Fang, Josephine Y; Nimni, Marcel

    2015-09-01

    The prevalence of cancer pain in patients with cancer is high. The majority of efforts are spent on research in cancer treatment, but only a small fraction focuses on cancer pain. Pain in cancer patients, viewed predominantly as a secondary issue, is considered to be due to the destruction of tissues, compression of the nerves, inflammation, and secretion of biological mediators from the necrotic tumor mass. As a result, opioid drugs have remained as the primary pharmacological therapy for cancer pain for the past hundred years. This report reviews evidence that cancer pain may be produced by the metabolic effects of two byproducts of cancer-high acidity in the cancer microenvironment and the secretion of formaldehyde and its metabolites. We propose the research and development of therapeutic approaches for preemptive, short- and long-term management of cancer pain using available drugs or nutraceutical agents that can suppress or neutralize lactic acid production in combination with formaldehyde scavengers. We believe this approach may not only improve cancer pain control but may also enhance the quality of life for patients.

  1. A hollow-waveguide gas correlation radiometer for ultra-precise column measurements of formaldehyde on Mars

    International Nuclear Information System (INIS)

    Wilson, Emily L; Riris, Haris; Heaps, William S; Neveu, Marc; Georgieva, Elena M

    2011-01-01

    We present preliminary results in the development of a miniaturized gas correlation radiometer that implements a hollow-core optical fiber (hollow-waveguide) gas correlation cell. The substantial reduction in mass and volume of the gas correlation cell makes this technology appropriate for an orbital mission—capable of pinpointing sources of trace gases in the Martian atmosphere. Here, we demonstrate a formaldehyde (H 2 CO) sensor and report a detection limit equivalent to ∼30 ppb in the Martian atmosphere. The relative simplicity of the technique allows it to be expanded to measure a range of atmospheric trace gases of interest on Mars such as methane (CH 4 ), water vapor (H 2 O), deuterated water vapor (HDO), and methanol (CH 3 OH). Performance of a formaldehyde instrument in a Mars orbit has been simulated assuming a 3 m long, 1000 µm inner diameter hollow-core fiber gas correlation cell, a 92.8° sun-synchronous orbit from 400 km with a horizontal sampling scale of 10 km × 10 km. Initial results indicate that for 1 s of averaging, a detection limit of 1 ppb is possible

  2. Ag-Modified In2O3/ZnO Nanobundles with High Formaldehyde Gas-Sensing Performance

    Directory of Open Access Journals (Sweden)

    Fang Fang

    2015-08-01

    Full Text Available Ag-modified In2O3/ZnO bundles with micro/nano porous structures have been designed and synthesized with by hydrothermal method continuing with dehydration process. Each bundle consists of nanoparticles, where nanogaps of 10–30 nm are present between the nanoparticles, leading to a porous structure. This porous structure brings high surface area and fast gas diffusion, enhancing the gas sensitivity. Consequently, the HCHO gas-sensing performance of the Ag-modified In2O3/ZnO bundles have been tested, with the formaldehyde-detection limit of 100 ppb (parts per billion and the response and recover times as short as 6 s and 3 s, respectively, at 300 °C and the detection limit of 100 ppb, response time of 12 s and recover times of 6 s at 100 °C. The HCHO sensing detect limitation matches the health standard limitation on the concentration of formaldehyde for indoor air. Moreover, the strategy to synthesize the nanobundles is just two-step heating and easy to scale up. Therefore, the Ag-modified In2O3/ZnO bundles are ready for industrialization and practical applications.

  3. Ag-Modified In2O3/ZnO Nanobundles with High Formaldehyde Gas-Sensing Performance

    Science.gov (United States)

    Fang, Fang; Bai, Lu; Song, Dongsheng; Yang, Hongping; Sun, Xiaoming; Sun, Hongyu; Zhu, Jing

    2015-01-01

    Ag-modified In2O3/ZnO bundles with micro/nano porous structures have been designed and synthesized with by hydrothermal method continuing with dehydration process. Each bundle consists of nanoparticles, where nanogaps of 10–30 nm are present between the nanoparticles, leading to a porous structure. This porous structure brings high surface area and fast gas diffusion, enhancing the gas sensitivity. Consequently, the HCHO gas-sensing performance of the Ag-modified In2O3/ZnO bundles have been tested, with the formaldehyde-detection limit of 100 ppb (parts per billion) and the response and recover times as short as 6 s and 3 s, respectively, at 300 °C and the detection limit of 100 ppb, response time of 12 s and recover times of 6 s at 100 °C. The HCHO sensing detect limitation matches the health standard limitation on the concentration of formaldehyde for indoor air. Moreover, the strategy to synthesize the nanobundles is just two-step heating and easy to scale up. Therefore, the Ag-modified In2O3/ZnO bundles are ready for industrialization and practical applications. PMID:26287205

  4. Synthesis and Structure Characterization of Phenol-Urea-Formaldehyde Resins in the Presence of Magnesium Oxide as Catalyst

    Directory of Open Access Journals (Sweden)

    Dong-Bin Fan

    2014-08-01

    Full Text Available The objective of this research was to provide a useful approach of polymer synthesis for accelerating the fast cure of phenol-urea-formaldehyde (PUF resin as wood adhesive by optimizing its structure and composition. The PUF resins containing high contents of very reactive groups such as para-methylol groups were synthesized by reacting methylolurea, phenol, and formaldehyde in the presence of magnesium oxide (MgO as catalyst. The effects of synthesis parameters including F/(P + U, OH/P, and MgO/P mole ratios on the structure, composition, curing characteristics, and their relationships of PUF resins were investigated. The results indicated that MgO seemed to be an efficacious catalyst for PUF resin synthesis and promote its faster cure. The increase in the F/(P + U mole ratio or/and OH/P mole ratio appeared to be beneficial for the formation of para-methylol groups and cocondensed methylene linkages between phenolic methylol groups and urea units, and for the removal of unreacted urea. In case of Catalyst/P mole ratio, an appropriate dosage of added metal-ion was very important for synthesizing the high-content reactive groups of PUF resins, otherwise leading to the reverse effects.

  5. Formaldehyde and tobacco smoke as alkylating agents: the formation of N-methylenvaline in pathologists and in plastic laminate workers.

    Science.gov (United States)

    Bono, Roberto; Romanazzi, Valeria; Pirro, Valentina; Degan, Raffaella; Pignata, Cristina; Suppo, Elisa; Pazzi, Marco; Vincenti, Marco

    2012-01-01

    Aim of this study was to investigate the relationships between the concentration of formaldehyde in air and the alkylation of hemoglobin to form a terminal N-methylenvaline residue in three occupationally exposed groups: a) technicians of pathology wards, b) workers of the plastic laminates industry, and c) a control group. All subjects recruited in this study were also tested on their smoking habits. Formaldehyde adsorbed on passive air samplers was quantified by HPLC with UV detection (360 nm), cotinine was quantified by GC-MS. Terminal hemoglobin N-methylenvaline was determined by treating globine under reducing conditions with pentafluorophenyl isothiocyanate to yield a derivative, subsequently detected by GC-MS. One-way analysis of variance was performed to compare among the three groups the biomarkers considered in this study. For air-FA and N-methylenvaline a difference between the three groups was detected (p alkylation to form N-methylenvaline molecular adduct in two occupationally exposed groups of subjects considered in the present study. In comparison with occupational exposition, tobacco smoke proved to have a minor impact on the formation of N-methylenvaline molecular adduct. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Modification and evaluation of thermal properties of melamine-formaldehyde/n-eicosane microcapsules for thermo-regulation applications

    International Nuclear Information System (INIS)

    Mohaddes, F.; Islam, S.; Shanks, R.; Fergusson, M.; Wang, L.; Padhye, R.

    2014-01-01

    A modified process to enhance the latent heat of fusion of n-eicosane microcapsules in melamine-formaldehyde shells is suggested for application in textiles. Deviations in melt enthalpy and phase change temperatures were determined for produced microcapsules by differential scanning calorimetry. Thermo-regulation efficiency of eicosane-microcapsule-treated fabrics was evaluated via fitting the Newton cooling law to the experimental data, and a new constant, α, was defined as the thermal delay factor. Scanning electron microscopy images and particle size distribution analysis were consistent and the particle size was found to be between 0.5 and 2.7 μm. Melamine-formaldehyde/n-eicosane microcapsule composition was confirmed using a Fourier transform infrared spectrophotometry. The microcapsules developed showed excellent heat storage capacities, over 162.4 J/g, over melting and crystallisation ranges compared with previous studies undertaken in this field. - Highlights: • Modified eicosane microcapsules with the highest phase change enthalpies were made. • Newton cooling law was fitted to determine thermal delay in PCM-substrates. • Fine microcapsule units with diameters less than 0.5 μm were prepared. • All pliable PCM-substrates can be thermally assessed using thermal logging method

  7. Effects of cryogenic temperature on the mechanical and failure characteristics of melamine-urea-formaldehyde adhesive plywood

    Science.gov (United States)

    Kim, Jeong-Hyeon; Choi, Sung-Woong; Park, Doo-Hwan; Park, Seong-Bo; Kim, Seul-Kee; Park, Kwang-Jun; Lee, Jae-Myung

    2018-04-01

    The present study investigates the applicability of melamine-urea-formaldehyde (MUF) resin plywood in cryogenic applications, including liquefied natural gas (LNG) carrier insulation systems. Phenolic-formaldehyde (PF) resin plywood has been extensively used as a structural material in industrial applications. However, many shortcomings of PF resin plywood have been reported, and replacement of PF resin plywood with a new material is necessary to resolve these problems. MUF resin plywood has the advantages of short fabrication time, low veneer cost, and economic feasibility compared to PF resin plywood. However, the mechanical and failure characteristics of MUF resin plywood have not yet been investigated at low temperature ranges. For this reason, adapting MUF resin plywood for cryogenic applications has been difficult, despite the many strong points of the material in engineering aspects. In this study, the effects of cryogenic temperature and thermal treatment on the mechanical characteristics of MUF resin plywood are investigated. The performance of MUF resin plywood is compared with that of PF resin plywood to verify the applicability of the material for use as a structural material in LNG insulation systems. The results demonstrate that MUF resin plywood has mechanical properties comparable with those of PF resin plywood, even at cryogenic conditions.

  8. Preparation of nano-TiO2/diatomite-based porous ceramics and their photocatalytic kinetics for formaldehyde degradation

    Science.gov (United States)

    Gao, Ru-qin; Sun, Qian; Fang, Zhi; Li, Guo-ting; Jia, Meng-zhe; Hou, Xin-mei

    2018-01-01

    Diatomite-based porous ceramics were adopted as carriers to immobilize nano-TiO2 via a hydrolysis-deposition technique. The thermal degradation of as-prepared composites was investigated using thermogravimetric-differential thermal analysis, and the phase and microstructure were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The results indicated that the carriers were encapsulated by nano-TiO2 with a thickness of 300-450 nm. The main crystalline phase of TiO2 calcined at 650°C was anatase, and the average grain size was 8.3 nm. The FT-IR absorption bands at 955.38 cm-1 suggested that new chemical bonds among Ti, O, and Si had formed in the composites. The photocatalytic (PC) activity of the composites was investigated under UV irradiation. Furthermore, the photodegradation kinetics of formaldehyde was investigated using the composites as the cores of an air cleaner. A kinetics study showed that the reaction rate constants of the gas-phase PC reaction of formaldehyde were κ = 0.576 mg·m-3·min-1 and K = 0.048 m3/mg.

  9. Comparison of the production rates of protozoa in the rumen estimated by using labelled live and formaldehyde treated mixed protozoal cells as marker

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.

    1979-01-01

    14 C-labelled mixed protozoal cells of rumen origin, treated with formaldehyde to protect their metabolism in the rumen, were used to estimate protozoa production in the rumen, and comparison was made of the growth obtained by injecting live labelled mixed rumen protozoal cells used earlier. (auth.)

  10. Tribological Behavior of TiC/a-C : H-Coated and Uncoated Steels Sliding Against Phenol-Formaldehyde Composite Reinforced with PTFE and Glass Fibers

    NARCIS (Netherlands)

    Shen, J.T.; Pei, Y.T.; Hosson, J.Th.M. De

    2013-01-01

    Tribological experiments on phenol-formaldehyde composite reinforced with polytetrafluoroethylene (PTFE) and glass fibers were performed against 100Cr6 steel and TiC/a-C:H thin film-coated 100Cr6 steel. In both cases, the coefficient of friction increases with increasing sliding distance until a

  11. Dual protection of wood surface treated with melamine-modified urea-formaldehyde resin mixed with ammonium polyphosphate against both fire and decay

    Science.gov (United States)

    Xing-xia Ma; Grant T. Kirker; Ming-liang Jiang; Yu-zhang Wu

    2016-01-01

    Surface coatings of melamine-modified urea-formaldehyde resins (MUFs) containing ammonium polyphosphate (APP) have been shown to significantly improve the fire retardancy of wood by prolonging the ignition time and reducing the heat release rate, total heat released, and mass loss rate. Dual protection of wood against both decay and fire has been proposed for remedial...

  12. Identification of mononuclear cells in human blood. II. Evaluation of morphological and immunological aspects of native and formaldehyde-fixed cell populations

    NARCIS (Netherlands)

    Schuit, H.R.E.; Hijmans, W.

    1980-01-01

    The presence of surface-associated immunoglobulins and Fc receptors on mononuclear cells from normal human blood waas investigated by the direct immunofluorescence technique combined with phase-contrast microscopy. Formaldehyde-fixed cells were compared to unfixed cells and to cells preincubated at

  13. Investigation of utilization of process of polyethylene waste of low density for creation of competitive materials with application of phenol formaldehyde oligomers

    International Nuclear Information System (INIS)

    Agakishieva, M.A.; Bilalov, Ya. M; Ibragimova, S. M; Dadasheva, G. I; Rezaei, Rudabeh

    2007-01-01

    Full text: The possibility of the utilization of low density polyethylene wastes by means of their modification with phenol formaldehyde oligomers (Ph FO) and PhFO with the thiourathenes has been investigation. Theology properties of the investigated systems showed that the obtained compositions can be able to be processed by the ordinary methods such as extrusion and casting

  14. CARIBIC DOAS observations of nitrous acid and formaldehyde in a large convective cloud

    Science.gov (United States)

    Heue, K.-P.; Riede, H.; Walter, D.; Brenninkmeijer, C. A. M.; Wagner, T.; Frieß, U.; Platt, U.; Zahn, A.; Stratmann, G.; Ziereis, H.

    2014-07-01

    The chemistry in large thunderstorm clouds is influenced by local lightning-NOx production and uplift of boundary layer air. Under these circumstances trace gases like nitrous acid (HONO) or formaldehyde (HCHO) are expected to be formed or to reach the tropopause region. However, up to now only few observations of HONO at this altitude have been reported. Here we report on a case study where enhancements in HONO, HCHO and nitrogen oxides (NOx) were observed by the CARIBIC flying laboratory (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). The event took place in a convective system over the Caribbean Sea in August 2011. Inside the cloud the light path reaches up to 100 km. Therefore the DOAS instrument on CARIBIC was very sensitive to the tracers inside the cloud. Based on the enhanced slant column densities of HONO, HCHO and NO2, average mixing ratios of 37, 468 and 210 ppt, respectively, were calculated. These data represent averages for constant mixing ratios inside the cloud. However, a large dependency on the assumed profile is found; for HONO a mixing ratio of 160 ppt is retrieved if the total amount is assumed to be situated in the uppermost 2 km of the cloud. The NO in situ instrument measured peaks up to 5 ppb NO inside the cloud; the background in the cloud was about 1.3 ppb, and hence clearly above the average outside the cloud (≈ 150 ppt). The high variability and the fact that the enhancements were observed over a pristine marine area led to the conclusion that, in all likelihood, the high NO concentrations were caused by lighting. This assumption is supported by the number of flashes that the World Wide Lightning Location Network (WWLLN) counted in this area before and during the overpass. The chemical box model CAABA is used to estimate the NO and HCHO source strengths which are necessary to explain our measurements. For NO a source strength of 10 × 109 molec cm-2 s-1 km-1 is found, which

  15. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    International Nuclear Information System (INIS)

    Adamson, D

    2007-01-01

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project Hanford Tank Waste Treatment and Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12-inch IX Column and sixteen cycles were completed in the 24-inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in upflow. Also, upflow Simulant Introduction produced an ideal level bed for the twenty cycles completed using upflow Simulant Introduction. Conversely, the three cycles conducted using downflow Simulant Introduction produced an uneven bed surface with erosion around the thermowells. The RF resin bed in both columns showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. Micrographs comparing representative bead samples before and after testing indicated no change in bead

  16. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D

    2007-01-09

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12-inch IX Column and sixteen cycles were completed in the 24-inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in upflow. Also, upflow Simulant Introduction produced an ideal level bed for the twenty cycles completed using upflow Simulant Introduction. Conversely, the three cycles conducted using downflow Simulant Introduction produced an uneven bed surface with erosion around the thermowells. The RF resin bed in both columns showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. Micrographs comparing representative bead samples before and after testing indicated no change in bead

  17. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D

    2006-11-08

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project-Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12 inch IX Column and sixteen cycles were completed in the 24 inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in upflow. Also, upflow Simulant Introduction produced an ideal level bed for the twenty cycles completed using upflow Simulant Introduction. Conversely, the three cycles conducted using downflow Simulant Introduction produced an uneven bed surface with erosion around the thermowells. The RF resin bed in both columns showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. Micrographs comparing representative bead samples before and after testing indicated no change in bead

  18. Sol-gel synthesis of iron catalysers supported on silica and titanium for selectively oxidising methane to formaldehyde

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Guerrero Fajardo

    2008-01-01

    Full Text Available Iron materials supported on silica were prepared by the sol-gel method for evaluating catalytic activity in selective o-xidation of methane to formaldehyde. Four catalysts were prepared, one corresponding to the silica support (catalyst 1S, another to the titanium support (catalyst 1T and two more having 0.5% weight iron loads, one for the silica su-pport (catalyst 2FS and the last one the titanium support (catalyst 2FT. The higher BET areas were 659 and 850 m2/g for catalysts 1S and 2FS, respectively while catalysts 1T and 2FT displayed areas of 65 and 54 m2/g, respec-tively. Scanning and transmission electronic microscopy displayed an amorphous structure in the silica-supported materials while titanium-supported materials displayed dense materials having defined structure. X-ray diffraction confirmed the silica’s amorphous structure in 1S and 2FS catalysts and displayed the 1T and 2FT catalysts’ anatase structure. The programmed temperature reduction for the 1S and 2FS catalysts did not display reducible species, while displaying hydrogen consumption peaks related to Fe3O4 reduction to α-Fe via FexO route for 1T and 2FT ca-talysts. The electronic spectroscopy X-ray photo confirmed the Fe(III specie as having 710.6 e.V binding energy for both 2FS and 2FT catalysts. Catalytic activity was carried out at atmospheric pressure in a quartz reactor, reaction mixture as CH4/O2/N2 =7.5/1/4 at 400-800°C temperature range. The reaction products were analysed by gas chromatography on Hayesep R and T columns using 5Å molecular screening. The best response for selective oxida-tion of methane to formaldehyde was displayed by the 2FS catalyst with 3.4% mol methane conversion at 650°C, 11.9% mol formaldehyde selectivity and 0.0211 g HCHO/Kg catalyst yield.

  19. Isotope effects and their implications for the covalent binding of inhaled [3H]- and [14C]formaldehyde in the rat nasal mucosa

    International Nuclear Information System (INIS)

    Heck Hd'; Casanova, M.

    1987-01-01

    DNA-protein crosslinks were formed in the nasal respiratory mucosa of Fischer-344 rats exposed for 3 hr to selected concentrations of [ 3 H]- and [ 14 C]formaldehyde ( 3 HCHO and H 14 CHO). In rats depleted of glutathione (GSH) and exposed to 10 ppm of 3 HCHO and H 14 CHO, the 3 H/ 14 C ratio of the fraction of the DNA that was crosslinked to proteins was significantly (39 +/- 6%) higher than that of the inhaled gas. This suggests an isotope effect, either on the formation of DNA-protein crosslinks by labeled HCHO or on the oxidation of labeled HCHO catalyzed by formaldehyde (FDH) or aldehyde dehydrogenase (AldDH). The possibility of an isotope effect on the formation of crosslinks was investigated using rat hepatic nuclei incubated with [ 3 H]- and [ 14 C]formaldehyde (0.1 mM, 37 degrees C). A small (3.4 +/- 0.9%) isotope effect was detected on this reaction, which slightly favored 3 HCHO over H 14 CHO in binding to DNA. The magnitude of this isotope effect cannot account for the high isotope ratio observed in the crosslinked DNA in vivo. The possibility of an isotope effect on the oxidation of 3 HCHO and H 14 CHO catalyzed by FDH was investigated using homogenates of the rat nasal mucosa incubated with [ 3 H]- and [ 14 C]formaldehyde at total formaldehyde concentrations ranging from 0.1 to 11 microM, NAD+ (1 mM), GSH (15 mM), and pyrazole (1 mM). The experiments showed that 3 HCHO is oxidized significantly more slowly than H 14 CHO under these conditions (Vmax/Km (H 14 CHO) divided by Vmax/Km ( 3 HCHO) = 1.82 +/- 0.11). A similar isotope effect was observed in the absence of GSH, presumably due to the oxidation of 3 HCHO and H 14 CHO catalyzed by AldDH

  20. Assessment of formaldehyde levels in local and imported fresh fish in Ghana: a case study in the Tamale Metropolis of Ghana.

    Science.gov (United States)

    Saba, Courage Kosi Setsoafia; Atayure, Seidu Isaac; Adzitey, Frederick

    2015-03-01

    Fish is an important source of protein all over the world, including in Ghana. The fishery sector plays a major role in meeting the domestic need of animal protein and also contributes greatly in foreign exchange earnings. The domestic supply of fish does not meet the demand, so Ghana imports fish and fish products from other countries. Media reports in Ghana have alleged the use of formaldehyde to preserve fish for increased shelf life and to maintain freshness. This research, therefore, sought to establish the levels of formaldehyde in imported and local fresh fish in the Tamale Metropolis by using a ChemSee formaldehyde and formalin detection test kit. Positive and negative controls were performed by using various concentrations of formalin (1, 10, 30, 50, 100, and 300 ppm) and sterile distilled water, respectively. Three times over a 6-month period, different fish species were obtained from five wholesale cold stores (where fish are sold in cartons) and some local sales points (where locally caught fish are sold). A total of 32 samples were taken during three different sampling sessions: 23 imported fish (mackerel, herring, horse mackerel, salmon, and redfish) and 9 local tilapia. The fish were cut, and 50 g was weighed and blended with an equal volume (50 ml) of sterile distilled water. Samples were transferred to test tubes and centrifuged. A test strip was dipped into the supernatant and observed for a color change. A change in color from white to pink or purple indicated the presence of formaldehyde in fish. The study showed that no formaldehyde was present in the imported and local fish obtained. The appropriate regulatory agencies should carry out this study regularly to ensure that fish consumed in Ghana is safe for consumption.

  1. Phenol-formaldehyde carbon with ordered/disordered bimodal mesoporous structure as high-performance electrode materials for supercapacitors

    Science.gov (United States)

    Cai, Tingwei; Zhou, Min; Han, Guangshuai; Guan, Shiyou

    2013-11-01

    A novel phenol-formaldehyde carbon with ordered/disordered bimodal mesoporous structure is synthesized by the facile evaporation induced self-assembly strategy under a basic aqueous condition with SiO2 particles as template. The prepared bimodal mesoporous carbons (BMCs) are composed of ordered mesoporous and disordered mesoporous with diameter of about 3.5 nm and 7.0 nm, respectively. They can be employed as supercapacitor electrodes in H2SO4 aqueous electrolyte after the simple acid-treatment. BMC exhibits an exceptional specific capacitance of 344 F g-1 at the current density of 0.1 A g-1, although it has a relatively low surface area of 722 m2 g-1. And the BMC electrode displays an excellent cycling stability over 10,000 cycles.

  2. Amperometric Detection of Sub-ppm Formaldehyde Using Single-Walled Carbon Nanotubes and Hydroxylamines: A Referenced Chemiresistive System.

    Science.gov (United States)

    Ishihara, Shinsuke; Labuta, Jan; Nakanishi, Takashi; Tanaka, Takeshi; Kataura, Hiromichi

    2017-10-27

    We report amperometric detection of formaldehyde (HCHO) using hydroxylamine hydrochloride and single-walled carbon nanotubes (SWCNTs). Hydroxylamine hydrochloride reacts with HCHO to emit HCl vapor, which injects a hole carrier into semiconducting SWCNTs. The increase of conductivity in SWCNTs is easily monitored using an ohmmeter. The debundling of SWCNTs with a metallo-supramolecular polymer (MSP) increased the active surface area in the SWCNTs network, leading to excellent sensitivity to HCHO with a limit of detection (LoD) of 0.016 ppm. The response of sensor is reversible, and the sensor is reusable. The selectivity to HCHO is 10 5 -10 6 times higher than interferences with other volatiles such as water, methanol, and toluene. Moreover, false-positive responses caused by a significant variation of humidity and/or temperature are successfully discriminated from true-positive responses by using two sensors, one with and the other without hydroxylamine hydrochloride, in a referenced system.

  3. Highly sensitive formaldehyde resistive sensor based on a single Er-doped SnO_2 nanobelt

    International Nuclear Information System (INIS)

    Li, Shuanghui; Liu, Yingkai; Wu, Yuemei; Chen, Weiwu; Qin, Zhaojun; Gong, Nailiang; Yu, Dapeng

    2016-01-01

    SnO_2 nanobelts (SnO_2 NBs) and Er"3"+-doped SnO_2 nanobelts (Er–SnO_2 NBs) were synthesized by thermal evaporation. The obtained samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersion spectrometer (EDS), and X-ray photoelectron spectrometer (XPS). It is found that Er–SnO_2 NBs have a good morphology with smooth surface and their thickness are about 30 nm, widths between 200 nm and 600 nm, and lengths 30–80 mm. The nanobelts with good morphology were taken to develop sensors based on a single Er–SnO_2 NB/SnO_2 NB for studying sensitive properties. The results reveal that the response of a single Er–SnO_2 nanobelt device is 9 to the formaldehyde gas with a shorter response (recovery time) of 17 (25) s.

  4. Physico-mechanical comparison of urea formaldehyde bonded particle board manufactured from jute sticks and wood of Trewia nudiflora

    Directory of Open Access Journals (Sweden)

    Abu Saleh Md. Golam Kibria

    2012-12-01

    Full Text Available This study is to know the physical and mechanical properties of particle board made up of jute sticks (jutex board and wood chips (woodex board of Trewia nudiflora. Two leading particle board manufacturing industries of Bangladesh were selected first which have the same manufacturing process and adhesive composition. Boards of available thicknesses were collected randomly. From each thickness category, three replications were taken. The parameters were studied as adhesive composition,mass of a board, density, bending strength, modulus of elasticity,surface soundness, tensile strength, screw withdrawal, pressure and pressing time. Urea formaldehyde resin is used to manufacture both types of particle board. For achieving the greater efficiency of boards, some chemical compounds were mixed with the resin. Due to the change in thicknesses, boards were not always different in terms of the physical and mechanical properties. Moreover, except the modulus of elasticity (MOE, woodex boards were superior to the properties of jutex boards. 

  5. Effects of drying time on the surface morphology evolution of urushiol-formaldehyde diethylenetriamine polymer microporous films

    International Nuclear Information System (INIS)

    Xu Yanlian; Bai Weibin; Luo Zhen; Jin Yao; Peng Bichen; Feng Lixia; Hu Binghuan; Lin Jinhuo

    2012-01-01

    Raw lacquer, a renewable and eco-friendly biopolymer material with excellent physico-mechanical properties, has been principally used to coat objects of high artistic and pleasing beauty for centuries. In previous reports, we studied microporous urushiol-based polymer (UBP) films by the water-assisted assembly method. The effect of drying time on the formation of breath figures with honeycomb patterns in the microporous films of urushiol-formaldehyde diethylenetriamine polymer (UFDP) was investigated in this paper. The pattern structure was studied with optical microscopy (OM) and scanning electron microscopy (SEM). The drying time, which is influenced by the reflux time, plays a decisive role in the morphology, such as pore size and distribution periodicity, of the microporous UFDP films.

  6. Expansive failure reactions and their prevention in the encapsulation of phenol formaldehyde type ion exchange resins in cement based systems

    Energy Technology Data Exchange (ETDEWEB)

    Constable, M.; Howard, C.G.; Johnson, M.A.; Jolliffe, C.B. (AEA Decommissioning and Waste Management, Winfrith (United Kingdom)); Sellers, R.M. (Nuclear Electric plc, Barnwood (United Kingdom))

    1992-01-01

    Lewatit DN is a phenol formaldehyde based ion exchange resin used to remove radioactive caesium from liquid waste streams such as fuel cooling ponds and effluents. This paper presents the results of a study of the encapsulation of the bead form of the resin in cement with particular reference to the mechanisms of its interaction with the encapsulant. When incorporated in pure ordinary Portland cement (OPC) at loadings in excess of 15 wt % an unstable product results due to expansion of the systems and at higher waste loadings failure results after only a few days. Evidence from differential scanning calorimetry, X-ray diffraction and scanning electron microscopy all indicate the cause of the expansive reaction to be the formation of crystals of calcium salts around and within the resin beads. Addition of BFS and sodium hydroxide prevent the formation of these salts by removal of calcium hydroxide from the system in other reactions. (author).

  7. Study of Propylene Glycol, Dimethylformamide and Formaldehyde Vapors Sensors Based on MWCNTs/SnO2 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Zaven Adamyan

    2017-06-01

    Full Text Available We present results of our research works related to the study of thick-film multiwall carbon nanotube/tin oxide nanocomposite sensors of propylene glycol (PG, dimethylformamide (DMF and formaldehyde (FA vapors derived using hydrothermal synthesis and sol-gel methods. Investigations of response/recovery characteristics in the 50-300 oC operating temperature range reveal that the optimal operating temperature for PG, DMF and FA vapor sensors, taking into account both high response and acceptable response and recovery times, are about 200 and 220 oC, respectively. A sensor response dependence on gas concentration in all cases is linear. The minimal propylene glycol and dimethylformamide gas concentrations at which the perceptible signal was registered by us were 13 ppm and 5 ppm, respectively.

  8. Formaldehyde sensor based on Ni-doped tetrapod-shaped ZnO nanopowder induced by external magnetic field

    Science.gov (United States)

    Bai, Zikui; Xie, Changsheng; Hu, Mulin; Zhang, Shunping

    2008-12-01

    The sensors based on Ni-doped ZnO nanopowder with tetrapod-shape (T-ZnO) were fabricated by screen-printing technique with external magnetic field in different direction. The morphologies and crystal structures of the thick film were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. Gas-sensing property of sensors responded to 100 ppm formaldehyde was also detected. The results show that the direction of magnetic field has crucial effect on the sensor sensitivity. The sensors based on 5 wt% Ni-doped T-ZnO induced by magnetic field in parallel direction to the thick film surface, has the optimization sensitivity, the shortest response and recovery time, which are 10.6, 16 and 15 s, respectively. The magnetic-field induction model and the gas-sensing mechanism of the Ni-doped T-ZnO are proposed.

  9. Efficient biological process characterization by definitive-screening designs: the formaldehyde treatment of a therapeutic protein as a case study.

    Science.gov (United States)

    Erler, Axel; de Mas, Nuria; Ramsey, Philip; Henderson, Grant

    2013-03-01

    As part of the process-characterization campaign of a candidate vaccine product, a recently developed class of three-level designs-definitive-screening designs-was employed to select a quadratic model that describes the effect of six input process parameters, including protein concentration, formaldehyde-to-protein ratio, lysine concentration, reaction duration, pH, and reaction temperature, on a formylation protein-crosslinking reaction. This design requires only 17 experimental runs. The resulting model was then used to simulate 10,000 runs that account for the variability in the inputs expected on manufacturing scale. The extent of protein polymerization was predicted to be within specifications for all simulated runs, demonstrating the robustness of the unit operation for subsequent process validation and future commercial manufacturing.

  10. Efficient transformation of corn stover to furfural using p-hydroxybenzenesulfonic acid-formaldehyde resin solid acid.

    Science.gov (United States)

    Zhang, Tingwei; Li, Wenzhi; An, Shengxin; Huang, Feng; Li, Xinzhe; Liu, Jingrong; Pei, Gang; Liu, Qiying

    2018-05-24

    In this work, p-hydroxybenzenesulfonic acid-formaldehyde resin acid catalyst (MSPFR), was synthesized by a hydrothermal method, and employed for the furfural production from raw corn stover. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption, elemental analysis (EA), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the MSPFR. The effects of reaction time, temperature, solvents and corn stover loading were investigated. The MSPFR presented high catalytic activity for the formation of furfural from corn stover. When the MSPFR/corn stover mass loading ratio was 0.5, a higher furfural yield of 43.4% could be achieved at 190 °C in 100 min with 30.7% 5-hydroxymethylfurfural (HMF) yield. Additionally, quite importantly, the recyclability of the MSPFR for xylose dehydration is good, and for the conversion of corn stover was reasonable. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Effects of drying time on the surface morphology evolution of urushiol-formaldehyde diethylenetriamine polymer microporous films

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yanlian, E-mail: ylxu@fjnu.edu.cn [College of Chemistry and Materials, Fujian Normal University, Fuzhou 350007 (China); Fujian Key Laboratory of Polymer Materials, Fuzhou 350007 (China); Bai Weibin; Luo Zhen; Jin Yao; Peng Bichen; Feng Lixia [College of Chemistry and Materials, Fujian Normal University, Fuzhou 350007 (China); Hu Binghuan [Fujian Key Laboratory of Polymer Materials, Fuzhou 350007 (China); Lin Jinhuo, E-mail: jhlin@fjnu.edu.cn [College of Chemistry and Materials, Fujian Normal University, Fuzhou 350007 (China); Fujian Key Laboratory of Polymer Materials, Fuzhou 350007 (China)

    2012-04-01

    Raw lacquer, a renewable and eco-friendly biopolymer material with excellent physico-mechanical properties, has been principally used to coat objects of high artistic and pleasing beauty for centuries. In previous reports, we studied microporous urushiol-based polymer (UBP) films by the water-assisted assembly method. The effect of drying time on the formation of breath figures with honeycomb patterns in the microporous films of urushiol-formaldehyde diethylenetriamine polymer (UFDP) was investigated in this paper. The pattern structure was studied with optical microscopy (OM) and scanning electron microscopy (SEM). The drying time, which is influenced by the reflux time, plays a decisive role in the morphology, such as pore size and distribution periodicity, of the microporous UFDP films.

  12. Patch testing with 2.0% (0.60 mg/cm2) formaldehyde instead of 1.0% (0.30 mg/cm2) detects significantly more contact allerg

    DEFF Research Database (Denmark)

    Pontén, Ann; Aalto-Korte, Kristiina; Agner, Tove

    2013-01-01

    .To validate earlier patch test results for comparison of 1% (wt/vol) and 2% (wt/vol) formaldehyde in water, and to investigate co-reactivity with quaternium-15. Materials and methods.In 12 dermatology clinics, 3591 patients were routinely patch tested simultaneously with 2.0% (wt/vol) (0.60 mg/cm(2) ) and 1.......0% (wt/vol) (0.30 mg/cm(2) ) formaldehyde. Micropipettes were used for delivering the exact dosage of the allergen. Results.Significantly more patients reacted to 2.0% formaldehyde than to 1.0% (3.4% versus 1.8%, p

  13. Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification.

    Science.gov (United States)

    Wang, Zhiqiang; Pei, Jingjing; Zhang, Jensen S

    2014-09-15

    Botanical filtration has been proved to be effective for indoor gas pollutant removal. To understand the roles of different transport, storage and removal mechanism by a dynamic botanical air filter, a series of experimental investigations were designed and conducted in this paper. Golden Pothos (Epipremnum aureum) plants was selected for test, and its original soil or activated/pebbles root bed was used in different test cases. It was found that flowing air through the root bed with microbes dynamically was essential to obtain meaningful formaldehyde removal efficiency. For static potted plant as normally place in rooms, the clean air delivery rate (CADR), which is often used to quantify the air cleaning ability of portable air cleaners, was only ∼ 5.1m(3)/h per m(2) bed, while when dynamically with air flow through the bed, the CADR increased to ∼ 233 m(3)/h per m(2) bed. The calculated CADR due to microbial activity is ∼ 108 m(3)/h per m(2) bed. Moisture in the root bed also played an important role, both for maintaining a favorable living condition for microbes and for absorbing water-soluble compounds such as formaldehyde. The role of the plant was to introduce and maintain a favorable microbe community which effectively degraded the volatile organic compounds adsorbed or absorbed by the root bed. The presence of the plant increased the removal efficiency by a factor of two based on the results from the bench-scale root bed experiments. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Halogen poisoning effect of Pt-TiO{sub 2} for formaldehyde catalytic oxidation performance at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaofeng; Cheng, Bei [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122#, Wuhan 430070 (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122#, Wuhan 430070 (China); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Ho, Wingkei, E-mail: keithho@ied.edu.hk [Department of Science and Environmental Studies and Centre for Education in Environmental Sustainability, The Hong Kong Institute of Education, Tai Po, N.T. Hong Kong (China)

    2016-02-28

    Graphical abstract: - Highlights: • The Pt-TiO{sub 2} catalyst is deactivated by adsorption of halogen ions. • The halogen poison is mainly attributed to the active site blocking of the Pt surface. • Halogen ions and Pt form Pt−X coordination bonds. • Large halogen diameter exhibits severe poisoning effect. - Abstract: Catalytic decomposition of formaldehyde (HCHO) at room temperature is an important method for HCHO removal. Pt-based catalysts are the optimal catalyst for HCHO decomposition at room temperature. However, the stability of this catalyst remains unexplored. In this study, Pt-TiO{sub 2} (Pt-P25) catalysts with and without adsorbed halogen ions (including F{sup −}, Cl{sup −}, Br{sup −}, and I{sup −}) were prepared through impregnation and ion modification. Pt-TiO{sub 2} samples with adsorbed halogen ions exhibited reduced catalytic activity for formaldehyde decomposition at room temperature compared with the Pt-TiO{sub 2} sample; the catalytic activity followed the order of F-Pt-P25, Cl-Pt-P25, Br-Pt-P25, and I-Pt-P25. Characterization results (including XRD, TEM, HRTEM, BET, XPS, and metal dispersion) showed that the adsorbed halogen ions can poison Pt nanoparticles (NPs), thereby reducing the HCHO oxidation activity of Pt-TiO{sub 2}. The poison mechanism is due to the strong adsorption of halogen ions on the surface of Pt NPs. The adsorbed ions form coordination bonds with surface Pt atoms by transferring surplus electrons into the unoccupied 5d orbit of the Pt atom, thereby inhibiting oxygen adsorption and activation of the Pt NP surface. Moreover, deactivation rate increases with increasing diameter of halogen ions. This study provides new insights into the fabrication of high-performance Pt-based catalysts for indoor air purification.

  15. Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (R-F) ion-exchange resin

    International Nuclear Information System (INIS)

    Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Bryan, S.A.; Hallen, R.T.; Brown, G.N.; Bray, L.A.; Linehan, J.C.

    1995-08-01

    The 177 underground storage tanks at the DOE's Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a 1,2,4-trisubstituted ring. CS-100 shows the presence of phenoxy-ether groups, and this may account for the much lower decontamination factor of CS-100 for cesium ion. Curing temperatures for the R-F resin were found to be optimal at 105--130C. At lower temperatures, insufficient curing, hence crosslinking, of the polymer resin occurs and selectivity for cesium drops. Curing at elevated temperatures leads to chemical degradation. Optimal particle size for R-F resin is in the range of 20--50 mesh-sized particles. R-F resin undergoes chemical degradation or oxidation which destroys ion-exchange sites. The ion-exchange sites (hydroxyl groups) are converted to quinones and ketones. CS-100, though it has much lower performance for cesium ion-exchange, is significantly more chemically stable than R-F resin. To gamma radiation, CS-100 is more radiolytically stable than R-F resin

  16. Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (R-F) ion-exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Bryan, S.A.; Hallen, R.T.; Brown, G.N.; Bray, L.A.; Linehan, J.C.

    1995-08-01

    The 177 underground storage tanks at the DOE`s Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a 1,2,4-trisubstituted ring. CS-100 shows the presence of phenoxy-ether groups, and this may account for the much lower decontamination factor of CS-100 for cesium ion. Curing temperatures for the R-F resin were found to be optimal at 105--130C. At lower temperatures, insufficient curing, hence crosslinking, of the polymer resin occurs and selectivity for cesium drops. Curing at elevated temperatures leads to chemical degradation. Optimal particle size for R-F resin is in the range of 20--50 mesh-sized particles. R-F resin undergoes chemical degradation or oxidation which destroys ion-exchange sites. The ion-exchange sites (hydroxyl groups) are converted to quinones and ketones. CS-100, though it has much lower performance for cesium ion-exchange, is significantly more chemically stable than R-F resin. To gamma radiation, CS-100 is more radiolytically stable than R-F resin.

  17. Development of a General Aza-Cope Reaction Trigger Applied to Fluorescence Imaging of Formaldehyde in Living Cells.

    Science.gov (United States)

    Bruemmer, Kevin J; Walvoord, Ryan R; Brewer, Thomas F; Burgos-Barragan, Guillermo; Wit, Niek; Pontel, Lucas B; Patel, Ketan J; Chang, Christopher J

    2017-04-19

    Formaldehyde (FA) is a reactive signaling molecule that is continuously produced through a number of central biological pathways spanning epigenetics to one-carbon metabolism. On the other hand, aberrant, elevated levels of FA are implicated in disease states ranging from asthma to neurodegenerative disorders. In this context, fluorescence-based probes for FA imaging are emerging as potentially powerful chemical tools to help disentangle the complexities of FA homeostasis and its physiological and pathological contributions. Currently available FA indicators require direct modification of the fluorophore backbone through complex synthetic considerations to enable FA detection, often limiting the generalization of designs to other fluorophore classes. To address this challenge, we now present the rational, iterative development of a general reaction-based trigger utilizing 2-aza-Cope reactivity for selective and sensitive detection of FA in living systems. Specifically, we developed a homoallylamine functionality that can undergo a subsequent self-immolative β-elimination, creating a FA-responsive trigger that is capable of masking a phenol on a fluorophore or any other potential chemical scaffold for related imaging and/or therapeutic applications. We demonstrate the utility of this trigger by creating a series of fluorescent probes for FA with excitation and emission wavelengths that span the UV to visible spectral regions through caging of a variety of dye units. In particular, Formaldehyde Probe 573 (FAP573), based on a resorufin scaffold, is the most red-shifted and FA sensitive in this series in terms of signal-to-noise responses and enables identification of alcohol dehydrogenase 5 (ADH5) as an enzyme that regulates FA metabolism in living cells. The results provide a starting point for the broader use of 2-aza-Cope reactivity for probing and manipulating FA biology.

  18. Interaction of Formaldehyde with the Rutile TiO 2 (110) Surface: A Combined Experimental and Theoretical Study

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaojuan; Zhang, Zhenrong; Yang, Chengwu; Bebensee, Fabian; Heibler, Stefan; Nefedov, Alexei; Tang, Miru; Ge, Qingfeng; Chen, Long; Kay, Bruce D.; Dohnalek, Zdenek; Wang, Yuemin; Woll, Christof

    2016-06-16

    The adsorption and reaction of formaldehyde (CH2O) on the oxidized rutile TiO2(110) surface were studied by temperature programmed desorption (TPD), scanning tunneling microscopy (STM), infrared reflection-absorption spectroscopy (IRRAS) and density functional theory (DFT) calculations. The experimental and theoretical data reveal the presence of various species depending on the temperature and coverage. After formaldehyde adsorption on TiO2(110) at 65 K, the multilayer CH2O was detected, which desorbs completely upon heating to 120 K. The isolated CH2O monomer was identified after submonolayer adsorption at low temperatures (45-65 K), in which CH2O is bound to the surface Ti5c sites via σ-donation and adopts a tilted geometry. With heating to higher temperatures the CH2O monomers remain stable up to 70 K and then undergo coupling reactions to form paraformaldehyde (polyoxymethylene, POM) at the Ti5c rows. The POM chain is oriented primarily along the [001] direction in a slightly disordered configuration. POM becomes the predominant species at 120 K and is decomposed releasing CH2O at about 250 K. In addition, dioxymethylene (DOM) was detected as minority species formed via reaction of Ti5c-bound CH2O with both neighboring O2c along the [1-10] direction and oxygen adatoms (Oad) at Ti5c sites along [001] on the oxidized TiO2(110) surface.

  19. Degradation of formaldehyde at high concentrations by phenol-adapted Ralstonia eutropha closely related to pink-pigmented facultative methylotrophs.

    Science.gov (United States)

    Habibi, Alireza; Vahabzadeh, Farzaneh

    2013-01-01

    The ability of the phenol-adapted Ralstonia eutropha to utilize formaldehyde (FD) as the sole source of carbon and energy was studied. Adaptation to FD was accomplished by substituting FD for glucose in a stepwise manner. The bacterium in the liquid test culture could tolerate concentrations of FD up to 900 mg L(-1). Degradation of FD was complete in 528 h at 30°C with shaking at 150 rpm (r = 1.67 mg L(-1) h(-1)), q = 0.035 g(FD) g(cell) (-1) h(-1). Substrate inhibition kinetics (Haldane and Luong equations) are used to describe the experimental data. At non-inhibitory concentrations of FD, the Monod equation was used. According to the Luong model, the values of the maximum specific growth rate (μ(max)), half-saturation coefficient (k(S)), the maximum allowable formaldehyde concentration (S(m)), and the shape factor (n) were 0.117 h(-1), 47.6 mg L(-1), 900 mg L(-1), and 2.2, respectively. The growth response of the test bacterium to consecutive FD feedings was examined, and the FD-adapted R. eutropha cells were able to degrade 1000 mg L(-1) FD in 150 h through 4 cycles of FD feeds. During FD degradation, formic acid metabolite was formed. Assimilation of FD, methanol, formic acid, and oxalate by the test bacterium was accompanied by the formation of a pink pigment. The carotenoid nature of the cellular pigment has been confirmed and the test bacterium appeared to be closely related to pink-pigmented facultative methylotrophs (PPFM). The extent of harm to soil exposed to biotreated wastewaters containing FD may be moderated due to the association between methylotrophic/oxalotrophic bacteria and plants.

  20. Low temperature synthesis of no-carrier-added [{sup 11}C]formaldehyde with metal hydrides and preparation of [1-{sup 11}C]1,2,3,4-Tetrahydro-{beta}-Carboline Derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Nader, M.W.; Zeisler, S.K.; Theobald, A.; Oberdorfer, F

    1998-12-01

    A comparative study has been performed on the selective reduction of cyclotron-produced [{sup 11}C]carbon dioxide to [{sup 11}C]formaldehyde with solutions of various complex metal hydrides at temperatures between -52 and +25 deg. C. Under optimal reaction conditions, lithium tetrahydridoaluminate gave the highest yield of [{sup 11}C]formaldehyde (58%, decay-corrected), followed by lithium triethylhydridoborate (34%) and sodium tetrahydridoborate (22%). Radiochemically pure [{sup 11}C]formaldehyde could be obtained with lithium tetrahydridoaluminate and sodium tetrahydridoborate, but not with lithium triethyl hydridoborate. The produced [{sup 11}C]formaldehyde was used for the synthesis of [1-{sup 11}C]1,2,3,4-tetrahydro-{beta}-carboline derivatives by the Pictet-Spengler reaction.