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Sample records for chlorophenols

  1. Integrated Criteria document Chlorophenols

    NARCIS (Netherlands)

    Slooff W; Bremmer HJ; Janus JA; Matthijsen AJCM; van Beelen P; van den Berg R; Bloemen HJT; Canton JH; Eerens HC; Hrubec J; Janssens H; Jumelet JC; Knaap AGAC; de Leeuw FAAM; van der Linden AMA; Loch JPG; van Loveren H; Peijnenburg WJGM; Piersma AH; Struijs J; Taalman RDFM; Theelen RMC; van der Velde JMA; Verburgh JJ; Versteegh JFM; van der Woerd KF

    1991-01-01

    Bij dit rapport behoort een bijlage onder hetzelfde nummer getiteld: "Integrated Criteria document Chlorophenols: Effects:" Auteurs : Janus JA
    Taalman RDFM; Theelen RMC en is de engelse editie van 710401003

  2. Chlorophenol Degradation Coupled to Sulfate Reduction

    OpenAIRE

    Häggblom, M M; Young, L. Y.

    1991-01-01

    We studied chlorophenol degradation under sulfate-reducing conditions with an estuarine sediment inoculum. These cultures degraded 0.1 mM 2-, 3-, and 4-chlorophenol and 2,4-dichlorophenol within 120 to 220 days, but after refeeding with chlorophenols degradation took place in 40 days or less. Further refeeding greatly enhanced the rate of degradation. Sulfate consumption by the cultures corresponded to the stoichiometric values expected for complete oxidation of the chlorophenol to CO2. Forma...

  3. RELATIVE POTENCY RANKING FOR CHLOROPHENOLS

    Science.gov (United States)

    Recently the National Center for Environmental Assessment-Cincinnati completed a feasibility study for developing a toxicity related relative potency ranking scheme for chlorophenols. In this study it was concluded that a large data base exists pertaining to the relative toxicity...

  4. A study of the growth of Pseudomonas putida CP1 on mono-chlorophenols

    OpenAIRE

    Fakhruddin, A. N. M.

    2003-01-01

    Pseudomonas putida CPI grew on all three mono-chlorophenol isomers when supplied as the sole source of carbon and energy. The biodegradability of the mono-chlorophenols followed the order: 4-chlorophenol > 2-chlorophenol > 3-chlorophenol. P. putida CPI was able to degrade 300 ppm 4-chlorophenol, 250 ppm 2-chlorophenol and 200 ppm of 3-chlorophenol. In the presence of fructose (1%, w/v) the organism could degrade 400 ppm 4-chlorophenol, 500 ppm 2-chlorophenol and 300 ppm 3-chlorophenol. Ch...

  5. Enzymatically mediated incorporation of 2-chlorophenol 4-chlorophenol into humic acids

    DEFF Research Database (Denmark)

    Lassen, P.; Randall, A.; Jørgensen, O.;

    1994-01-01

    A possible route to chlorinated humic substances in the environment, is an indirect chlorination of humic material by enzymatically mediated incorporation of low molecular weight organo-chlorine compounds into the humic skeleton. The enzymatically mediated incorporation of 2-chlorophenol and 4......-chlorophenol into humic acids by Horseradish Peroxidase is reported. The incorporation is accompanied by a significant polymerization of the chlorophenols. The stability of the chlorinated humic acids as well as the environmental implication are discussed....

  6. INDUCTION OF PROPHAGE LAMBDA BY CHLOROPHENOLS

    Science.gov (United States)

    Chlorinated phenols, which are used primarily as wood preservatives and fungicides, are present in most air, water, and soil samples in industrialized areas as well as in urine and body fat of most people. e have examined the ability of phenol and the 19 isomers of chlorophenol t...

  7. Bacterial degradation of chlorophenols and their derivatives

    OpenAIRE

    Arora, Pankaj Kumar; Bae, Hanhong

    2014-01-01

    Chlorophenols (CPs) and their derivatives are persistent environmental pollutants which are used in the manufacture of dyes, drugs, pesticides and other industrial products. CPs, which include monochlorophenols, polychlorophenols, chloronitrophenols, chloroaminophenols and chloromethylphenols, are highly toxic to living beings due to their carcinogenic, mutagenic and cytotoxic properties. Several physico-chemical and biological methods have been used for removal of CPs from the environment. B...

  8. Enhancement of 4-chlorophenol biodegradation using glucose

    Energy Technology Data Exchange (ETDEWEB)

    Tarighian, Alireza; Hill, Gordon; Headley, John [Division of Environmental Engineering, University of Saskatchewan, 105 Maintenance Road, S7N 5C5, Saskatoon, SK (Canada); Pedras, Soledad [Department of Chemistry, University of Saskatchewan, 110 Science Place, S7N 5C9, Saskatoon, SK (Canada)

    2003-03-01

    Toxic, xenobiotic chemicals present challenging problems for the environment since they are normally resistant to biodegradation. Sometimes it is possible to induce biodegradation activity by the use of growth cosubstrates. In this study, pure solutions and binary mixtures of glucose, phenol and 4-chlorophenol have been metabolized in batch cultures by a pure strain of Pseudomonas putida. Following a lag period during which slow growth and low production of biomass occurred, phenol was metabolized according to the Monod model. Glucose was also metabolized according to the Monod model but exponential growth commenced immediately after inoculation with no noticeable lag phase. Biokinetic behavior for growth on a mixture of phenol and glucose paralleled the behavior on individual substrates with simultaneous consumption of both substrates. 4-chlorophenol was not consumed as a sole substrate by Pseudomonas putida but was consumed as a cometabolite with either glucose or phenol acting as the primary growth cosubstrate. Surprisingly, glucose was found to be the superior growth cosubstrate, suggesting that inexpensive sugars can be used to enhance the biodegradation of chlorophenol-contaminated sites. Glucose and the excreted metabolic products of the biodegradation process, including a bright yellow pigment, demonstrated negligible toxicity towards Artemia salina, unlike the phenol and 4-chlorophenol substrates. (orig.)

  9. Degradation of chlorophenols by a defined mixed microbial community.

    OpenAIRE

    E. Schmidt; Hellwig, M.; Knackmuss, H J

    1983-01-01

    Synthetic sewage containing phenol, acetone, and alkanols plus 4-chlorophenol or a mixture of isomeric chlorophenols is completely degraded by a defined mixed culture with Pseudomonas sp. strain B13 as a chlorocatechol-dissimilating member of the community. Total degradation of the organic carbon was indicated by release of stoichiometric amounts of chloride and low content of dissolved organic carbon in the cell-free effluents. During adaptation to high loads of chlorophenols the initial met...

  10. Reductive dehalogenation of chlorophenols by Desulfomonile tiedjei DCB-1.

    OpenAIRE

    Mohn, W W; Kennedy, K J

    1992-01-01

    Reductive dehalogenation of chlorophenols has been reported in undefined anaerobic cultures but never before in an anaerobic pure culture. We found that the sulfate-reducing bacterium Desulfomonile tiedjei DCB-1 reductively dehalogenates pentachlorophenol (PCP) and other chlorophenols. The maximum rate of PCP dechlorination observed was 54 mu mol of Cl- h-1 g of protein-1. 3-Chlorobenzoate appeared to serve as a required inducer for PCP dehalogenation; however, neither PCP nor 3-chlorophenol ...

  11. Third-order optical nonlinearity of chlorophenols

    Science.gov (United States)

    Maloney, C.; Blau, W.

    1988-02-01

    Degenerate four-wave mixing of infrared (1.064 μm) pulses with 130 ps duration was studied in o-, p- and m- chlorophenols. Nonlinear susceptibilities χ (3) of (5.5-6.0) × 10 -20 m 2/V 2 were measured. By temporally delaying the incidence of the second pump pulse contributions from an optical Kerr effect and an electrostrictive effect are observed.

  12. Self-assembly of chlorophenols in water

    OpenAIRE

    Rogalska, Ewa; Rogalski, Marek; Gulik-Krzywicki, Tadeusz; Gulik, Annette; Chipot, Christophe

    1999-01-01

    In saturated solutions of some di- and trichlorophenols, structures with complex morphologies, consisting of thin, transparent sheets often coiling into helices and ultimately twisting into filaments, were observed under the optical microscope. Freeze-fracture electron microscopy, x-ray diffraction, phase diagrams, and molecular modeling were performed to elucidate the observed phenomena. Here, we present evidence that the chlorophenols studied, when interacting with water, self-assemble into...

  13. Prediction of diffusion coefficients of chlorophenols in water by computer simulation

    OpenAIRE

    Martins, Luís F. G.; Parreira, M. Cristina B.; Prates Ramalho, João P.; Morgado, Pedro; Filipe, Eduardo. J. M.

    2015-01-01

    Intra-diffusion coefficients of seven chlorophenols (2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, 2,4,6-dichlorophenol and pentachlorophenol) in water were determined by computer simulation (molecular dynamics) for dilute solutions at three different temperatures and the corresponding mutual diffusion coefficients estimated. The mutual diffusion coefficients of 2-chlorophenol in water agree with the available experimental results from the...

  14. Dechlorination of chlorophenols by zero valent iron impregnated silica

    Institute of Scientific and Technical Information of China (English)

    Praveena Juliya Dorathi; Palanivelu Kandasamy

    2012-01-01

    Laboratory studies were conducted to find out the efficacy of uniquely prepared zero valent iron impregnated silica in transforming xenobiotic chlorophenols namely 4-chlorophenol,2,4-dichlorophenol and 2,4,6-trichlorophenol.Continuous mode colunm experiments were performed to investigate the transformation of chlorophenols by varying pH,column height,flow rate and initial chlorophenol concentration.Reusability study of the zero valent iron impregnated silica was studied as well as the morphological changes and the chemical composition of the catalyst medium were also investigated.Dechlorination kinetic studies were conducted and the order of dechlorination of chlorophenols was found to be 2,4,6-trichlorophenol > 2,4-dichlorophenol > 4-chlorophenol.The optimum pH,column height and flow rate were found to be 7,20 cm and 0.75 L/hr respectively for all chlorophenols in the reaction duration of 4 hr.Intermediates formed during dechlorination study were identified by gas chromatography-mass spectroscopy analysis.This method was applied to real pulp and paper wastewater and was found satisfactory.

  15. Photo-degradation of chlorophenols in the aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Czaplicka, Marianna [Institute of Non-Ferrous of Metals, 44-100 Gliwice, Sowinskiego St. 5 (Poland)]. E-mail: mariannac@imn.gliwice.pl

    2006-06-30

    The review presents the chlorophenols photo-degradation kinetics and mechanism in the aquatic environment under UV-vis in the presence of hydroxyl radicals and singlet oxygen. The influence of experimental parameters e.g. pH, dissociation degree, presence of oxidants in solution, number and position of Cl atoms on the quantum yield and reaction rate constant of chlorophenols are discussed. Mechanisms of photolysis, reaction with hydroxyl radicals, singlet oxygen and secondary reactions for mono-, di-, tri-, tetra- and pentachlorophenol are proposed. The pathways for intermediate reactions e.g. dechlorination, oxidation, dimerization for chlorophenols are also presented.

  16. REVIEWS OF THE ENVIRONMENTAL EFFECTS OF POLLUTANTS: XI. CHLOROPHENOLS

    Science.gov (United States)

    This study reviews the health and environmental effects of chlorophenols. It includes discussions of physical and chemical properties; analytical methods; biological aspects in microorganisms, plants, animals, and humans; environmental distribution and transformation; and environ...

  17. Regiospecificity of Chlorophenol Reductive Dechlorination by Vitamin B12s

    OpenAIRE

    Smith, Mark H.; Woods, Sandra L.

    1994-01-01

    Vitamin B12, reduced by titanium (III) citrate to vitamin B12s, catalyzes the reductive dechlorination of chlorophenols. Reductive dechlorination of pentachlorophenol and of all tetrachlorophenol and trichlorophenol isomers was observed. Reaction of various chlorophenols with vitamin B12 favored reductive dechlorination at positions adjacent to another chlorinated carbon, but chlorines ortho to the hydroxyl group of a phenol were particularly resistant to reductive dechlorination, even if the...

  18. Bioadsorption of 4-Chlorophenol to the Activated Sludge

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The adsorption behaviour of 4-chlorophenol from aqueous solution to activated sludge was quantitatively characterized in this paper. The effects of the initial pH values, initial chlorophenol concentration and adsorbent dosage on bioadsorption were investigated. The maximum adsorption capacity was found to be 110.5 mg/g at 100 mg/L initial concentration. The Freundlich and Langmuir adsorption isotherms were applied to describe the biosorption processes and the isotherm constants were evaluated.

  19. Improved wet peroxide oxidation strategies for the treatment of chlorophenols

    OpenAIRE

    Muñoz, Macarena; de Pedro, Zahara M.; Casas, José Antonio; Rodríguez, Juan José

    2013-01-01

    Different advanced oxidation strategies have been investigated for the treatment of chlorophenols in aqueous phase with the aim of improving the removal efficiency in terms of mineralization, remanent by-products and kinetics. Those strategies were homogeneous Fenton-like oxidation and CWPO with two different own-prepared FexOy/γ-Al2O3 catalysts. The intensification of the process by increasing the temperature has been also evaluated. CWPO of chlorophenols with those catalysts has proved to b...

  20. Investigation of the Interactions Among Grass, Chlorophenols and Microbes

    OpenAIRE

    Crane, Cynthia Elizabeth

    1999-01-01

    Studies were conducted to explore the interactions among rye grass, chlorophenols and microorganisms. The objectives were to examine some of the processes by which plants affect the fate of subsurface organic contaminants. The research was divided into three studies: interactions between live grasses and 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP); physico-chemical interactions between the three chlorophenols and root tissue; and effect of root exudate...

  1. ANALYTICAL METHODOLOGY FOR THE DETERMINATION OF CHLOROPHENOLS IN HUMAN AND ENVIRONMENTAL SAMPLES

    Science.gov (United States)

    Methodology is presented for the determination of chlorophenols in human and environmental media. The methodology for air samples is a modification of the analysis of chlorophenols in blood and has not been fully investigated as to quantitative reliability.

  2. ADSORPTION CHARACTERISTICS OF CHLOROPHENOLS FROM AQUATIC SYSTEMS BY HYPERCROSSLINKED RESINS MODIFIED WITH BENZOYL GROUP

    Institute of Scientific and Technical Information of China (English)

    Jing-ping Wang; Zheng-hao Fei

    2006-01-01

    A hypercrosslinked polymeric adsorbent (ZH-03) for adsorbing and removing chlorophenolic compounds from their aqueous solutions was studied, including the static adsorption. The equilibrium adsorption data were fit to Freundlich adsorption isothermic models to evaluate the model parameters. Thermodynamic studies on the adsorption of chlorophenolic compounds on ZH-03 indicated that there were chemisorption transitions for 2,4,6-trichlorophenol and physical adsorption processes for 2-chlorophenol and 2,6-chlorophenol, and ZH-03 showed the homogeneous nature of the adsorbent surface.Column adsorption for chlorophenols wastewater shows the advantages of the ZH-03 adsorbent for adsorbing the following chlorophenolic compounds as 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol. Sodium hydroxide was used for desorpting chlorophenols from ZH-03 and showed excellent performance.

  3. Mono-chlorophenol degradation by pseudomonas putida CP1 and a mixed microbial population

    OpenAIRE

    Farrell, Alan

    2000-01-01

    A commercial mixed culture, Biolyte HAB, degraded mono-chlorophenols using a metci- cleavage pathway. 2- and 3-chlorophenol degradation was incomplete, leading to the accumulation of dead-end metabolites. Biolyte HAB was capable of the complete degradation of 2.34 mM 4-chlorophenol, via the intermediate 5-chloro-2- hydroxymuconic semialdehyde, using the meta- cleavage pathway. Pseudomonas putida CPI degraded mono-chlorophenols to completion via an orthocleavage pathway. The ability of P. ...

  4. Toxicological Profile of Chlorophenols and Their Derivatives in the Environment: The Public Health Perspective

    OpenAIRE

    Igbinosa, Etinosa O.; Emmanuel E. Odjadjare; Chigor, Vincent N.; Isoken H. Igbinosa; Emoghene, Alexander O.; Ekhaise, Fredrick O.; Igiehon, Nicholas O.; Idemudia, Omoruyi G.

    2013-01-01

    Chlorophenol compounds and their derivatives are ubiquitous contaminants in the environment. These compounds are used as intermediates in manufacturing agricultural chemicals, pharmaceuticals, biocides, and dyes. Chlorophenols gets into the environment from a variety of sources such as industrial waste, pesticides, and insecticides, or by degradation of complex chlorinated hydrocarbons. Thermal and chemical degradation of chlorophenols leads to the formation of harmful substances which consti...

  5. Precursor anion states in dissociative electron attachment to chlorophenol isomers

    Science.gov (United States)

    Kossoski, F.; Varella, M. T. do N.

    2016-07-01

    We report a theoretical study on low-energy (chlorophenol isomers, namely, para-chlorophenol (pCP), meta-chlorophenol (mCP), and ortho-chlorophenol (oCP). The calculations were performed with the Schwinger multichannel method with pseudopotentials, and analysis of the computed integral cross sections and virtual orbitals revealed one σCCl ∗ , one σOH ∗ , and three π∗ shape resonances. We show that electron capture into the two lower lying π∗ orbitals initiates dissociative processes that lead to the elimination of the chloride ion, accounting for the two overlapping peaks where this fragment was observed. Despite the relatively small differences on the energetics of the π∗ resonances, a major isomeric effect was found on their corresponding autodetachment lifetimes, which accounts for the observed increasing cross sections in the progression pCP chlorophenols and phenol actually takes place by a mechanism in which the incoming electron is directly attached to the dissociative σOH ∗ orbital.

  6. Highly efficient adsorption of chlorophenols onto chemically modified chitosan

    Science.gov (United States)

    Zhou, Liang-Chun; Meng, Xiang-Guang; Fu, Jing-Wei; Yang, Yu-Chong; Yang, Peng; Mi, Chun

    2014-02-01

    A novel chemically modified chitosan CS-SA-CD with phenol and β-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer-Emmett-Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m2/g), pore volume (7.29 × 10-3 mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m2/g, 2.00 × 10-3 mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and sbnd OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80-91% adsorption efficiency.

  7. Efficient oxidative degradation of 2-chlorophenol and 4-chlorophenol over supported CuO-based catalysts

    Institute of Scientific and Technical Information of China (English)

    Jingjing Li; Yang Hu; Wenhui Lü; Lei Shi; Qi Sun; Yonggang Zhou; Jianfeng Xu; Jian Wang; Bizhong Shen

    2011-01-01

    A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) were prepared,and the supported CuO catalysts were studied particularly.The supported CuO catalysts were characterized by XRD and NH3-TPD techniques,in which CuO/γ-Al2O3 exhibited high degradation activity.The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably,in which Na2O was more efficient than K2O.Over CuO/γ-Al2O3-Na2O,CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ℃ for 2 h.The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs.In addition,the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.

  8. Sorption of chlorophenols onto fruit cuticles and potato periderm

    Institute of Scientific and Technical Information of China (English)

    Yungui Li; Yingqing Deng; Baoliang Chen

    2012-01-01

    To better understand the interaction mechanisms of plant surfaces with polar organic compounds,sorption of 4-chlorophenol,2,4-dichlorophenol,and 2,4,6-trichlorophenol by fruit cuticles (i.e.,tomato,apple,and pepper),and potato tuber periderm were investigated.The roles of cuticular components (waxes,cutin,cutan and sugar) on sorption of chlorophenols are quantitatively compared.Cutin and waxes govern the sorption capacity of bulk apple cuticle by hydrophobic interactions.Potato periderm with highest sugar content exhibits the lowest sorption capability for the chlorophenols.With the increase of hydrophobicity (i.e.,Kow ) of sorbate,the relative contribution of lipophilic components (wax,cutin and cutan) on total sorption increases,however,the ratios of Koc to Kow decreases due to increasing ionization degree of sorbates.

  9. Catalytic wet Air Oxidation of o-Chlorophenol in Wastewater

    Institute of Scientific and Technical Information of China (English)

    徐新华; 汪大翬

    2003-01-01

    Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatment of o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence of catalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removed by wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperature of 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited high catalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCr was removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had better catalytic activity for the degradation of o-chlorophenol in wastewater.

  10. Chlorobenzenes and chlorophenols in chloronaphthalene Halowax formulations

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Takashi; Ishikawa, Yukari; Noma, Yukio; Sakai, Shin-Ichi [National Institute for Environmental Studies, Tsukuba (Japan); Gutfranska, M.; Lukaszewicz, E.; Falandysz, J. [Gdansk Univ. (Poland). Dept. of Environmental Chemistry and Ecotoxicology

    2004-09-15

    Polychlorinated naphthalenes (PCNs; chloronaphthalenes, CNs) are industrial chemicals, that starting from the year 1900 become increasingly popular substances. Initially CNs were used to substitute natural waxes and rubber, next as insulating material in capacitors and for cable manufacture, and further found many other appliances. The restrictions on use of CNs, initially largely voluntary but also official in some countries came into force in 1972-1995. CNs were manufactured in Europe (Nibren, Seekay and Clonacire waxes etc.) and USA (Halowax waxes) using gaseous chlorination of molten naphthalene in presence of a catalyst and applying high pressure and temperature. It can be assumed that technical naphthalene used for manufacture of technical CN mixtures can contain some impurities such as benzene and phenol. These impurities should be chlorinated to form some chlorinated compounds during the production of technical CN preparations. Hence, some toxic outbreaks noted in man and animals after exposure to mixtures of CN can be partly also due to exposure to byside impurities such as chlorobenzenes (CBzs) and chlorophenols (CPhs). In this study an attempt has been taken to examine if CBzs and CPhs are formed during synthesis of CNs and contribute as toxic impurities found in a final product, which is represented by seven of various type the technical CN Halowax formulations. There is no earlier report available on contamination by CBzs and CPhs of the Halowaxes.

  11. The mechanism and pathway of the ozonation of 4-chlorophenol in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    PI Yunzheng; WANG Jianlong

    2006-01-01

    The removal efficiency of 4-chlorophenol by ozonation was studied, and the reaction mechanism and characteristic of ozonation of 4-chlorophenol were investigated. Ozone and hydroxyl radicals are two strong oxidants during the process of ozonation. The experimental results showed that when there was no scavenger to inhibit OH· radicals, an intermediate product, hydrogen peroxide was formed during the ozonation of 4-chlorophenol. Hydrogen peroxide reacted with ozone at neutral pH and produced hydroxyl radicals. Ozone at the dosage of 113 mg/L could remove 20 mg/L4-chlorophenol and 39% TOC. With the complete inhibition of hydroxyl radicals, molecular ozone could effectively destroy 4-chlorophenol to form 4-quinone, which was subsequently oxidized to formic acid and oxalic acid. Two reaction pathways of the degradation of 4-chlorophenol by ozone and O3/OH· were proposed in this study. Ozonation is an effective method for reducing 4-chlorophenol,and has potential to practical application.

  12. Reaction mechanism of 3-chlorophenol with OH, H in aqueous solution.

    Science.gov (United States)

    Zhu, Jie; Chen, Ye-Fei; Dong, Wen-Bo; Pan, Xun-Xi; Hou, Hui-Qi

    2003-01-01

    The reaction mechanism of 3-chlorophenol with OH, H in aqueous solution was studied by transient technology. The 3-chlorophenol aqueous solutions have been saturated with air or N2 previously. Under alkaline condition, the reaction of OH radical with 3-chlorophenol produces 3-chlorinated phenoxyl radical, with the absorption peaks at 400 nm and 417 nm. Under neutral condition, the reaction of OH radical with 3-chlorophenol produces OH-adduct with the maximal absorption at about 340 nm. And in acid solution, the reaction of H with 3-chlorophenol produces H-adduct with the maximal absorption at about 320 nm. 3-chlorophenol is compared with 4-and 2-chlorophenols from the free radical pathways. The results show that the positions of chlorine on the aromatic ring strongly influence the dehalogenation and degradation process.

  13. Reaction mechanism of 3-chlorophenol with OH, H in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The reaction mechanism of 3-chlorophenol with OH, H inaqueous solution was studied by transient technology. The3-chlorophenol aqueous solutions have been saturated with air or N2previously. Under alkaline condition, the reaction of OH radicalwith 3-chlorophenol produces 3-chlorinated phenoxyl radical, withthe absorption peaks at 400 nm and 417 nm. Under neutral condition,the reaction of OH radical with 3-chlorophenol produces OH-adductwith the maximal absorption at about 340 nm. And in acid solution,the reaction of H with 3-chlorophenol produces H-adduct with themaximal absorption at about 320 nm. 3-chlorophenol is compared with4- and 2-chlorophenols from the free radical pathways. The resultsshow that the positions of chlorine on the aromatic ring stronglyinfluence the dehalogenation and degradation process.

  14. Methanization of 2 chlorophenol (2CP) in presence of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Beristain, L. M.; Cuervo-Lopez, F. M.; Ramirez, F.

    2009-07-01

    Chlorophenols, very toxic organic compounds, are widely distributed in soils and water. These substances are related to cellular damage as they have mutagenic and carcinogenic characteristics. Aromatic compounds have been eliminated from wastewater under methanogenic conditions; however, in most of the cases the elimination rates are low and some toxic intermediates might be accumulated. (Author)

  15. Degradation of chlorophenol by in-situ electrochemically generated oxidant

    Institute of Scientific and Technical Information of China (English)

    丛燕青; 吴祖成; 叶倩; 谭天恩

    2004-01-01

    A novel in-situ electrochemical oxidation method was applied to the degradation of wastewater containing chlorophenol. Under oxygen sparging, the strong oxidant, hydrogen dioxide, could be in-situ generated through the reduction of oxygen on the surface of the cathode. The removal rate ofchlorophenol could be increased 149% when oxygen was induced in the electrochemical cell. The promotion factor was estimated to be about 82.63% according to the pseudo-first-order reaction rate constant (min-1). Important operating parameters such as current density, sparged oxygen rate were investigated. Higher sparged oxygen rate could improve the degradation of chlorophenol. To make full use of oxygen, however, sparged oxygen rate of 0.05 m3/h was adopted in this work. Oxidation-reduction potential could remarkably affect the generation of hydrogen peroxide. It was found that the removal rate of chlorophenol was not in direct proportion to the applied current density. The optimum current density was 3.5 mA/cm2 when initial chlorophenol concentration was 100 mg/L and sparged oxygen rate was 0.05 m3/h.

  16. Degradation of chlorophenol by in-situ electrochemically generated oxidant

    Institute of Scientific and Technical Information of China (English)

    丛燕青; 吴祖成; 叶倩; 谭天恩

    2004-01-01

    A novel in-situ electrochemical oxidation method was applied to the degradation of wastewater containing chlorophenol. Under oxygen sparging, the strong oxidant, hydrogen dioxide, could be in-situ generated through the reduction of oxygen on the surface of the cathode. The removal rate ofchlorophenol could be increased 149% when oxygen was induced in the electrochemical cell. The promotion factor was estimated to be about 82.63% according to the pseudo-first-order reaction rate constant (min-1). Important operating parameters such as current density, sparged oxygen rate were investigated.Higher sparged oxygen rate could improve the degradation of chlorophenol. To make full use of oxygen, however, sparged oxygen rate of 0.05 m3/h was adopted in this work. Oxidation-reduction potential could remarkably affect the generation of hydrogen peroxide. It was found that the removal rate of chlorophenol was not in direct proportion to the applied current density. The optimum current density was 3.5 mA/cm2 when initial chlorophenol concentration was 100 mg/L and sparged oxygen rate was 0.05 m3/h.

  17. Optimization of Fenton pretreatment for 2-chlorophenol solution

    Institute of Scientific and Technical Information of China (English)

    贺仲兵; 刘云国; 肖玉

    2013-01-01

    Fenton oxidation was used as the pretreatment of 2-chlorophenol wastewater with the objective of dechlorination, as it was considered that after breakage of aryl—Cl bond, the generated intermediates may be easily biodegraded. Hence, the optimization of pH and the low Fenton reagent doses for dechlorination was investigated. More than 99% dechlorination is obtained at the optimal pH 4 and the Fenton reagent doses of 86 mmol/L H2 O2 and 2.87 mmol/L Fe2+. The corresponding 2-chlorophenol is degraded completely, 80.02% COD is also removed, and the biodegradability, evaluated in terms of the BOD5 /COD ratio, is increased up to 0.41. To test the effect of this pretreatment, the pretreated 2-chlorophenol wastewater was fed to a sequencing batch reactor(SBR). The results show that complete mineralization is achieved. It is demonstrated that, for the treatment of recalcitrant compounds like 2-chlorophenol, the Fenton pretreatment could be quite effective and economical for enhancing the biodegradability in a Fenton-biological coupled system.

  18. 2-chlorophenol oxidation kinetic by photo-assisted Fenton process

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Experimental data are presented to test and validate a kinetic model for the oxidation of 2-chlorophenol wastewater by photo-assistedFenton process. The data showed that this process had produced good effects under acidic conductions. Up to 90% 2-chlorophenol was removedafter 90-minute reaction time with H2 O2 of 25 % CODcr in while in UV/H2 O2 system only 16.8% 2-chlorophenol was removed after one hourtreatment. The optimal pH in this reaction occurred between pH 3.0 and pH 4.0. The reaction kinetics for photo-assisted Fenton processexperimented in this research was investigated. Kinetic models were proposed for the treatment of 2-chlorophenol wastewater. The reaction wasfound to follow the 2nd order. The equations of reaction kinetics are as follows: - dt/d[RH]= KRH [ RH] [ H2O2 ]0exp(-KH2O2t); -dt/d[CODcr]= KCODCr[CODCr][ H2O2 ]0exp( - K't). The prediction of the models was found to be in a good agreement with experimentalresults, thus confirming the proposed reaction mechanism.

  19. Highly efficient adsorption of chlorophenols onto chemically modified chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Liang-Chun [Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China); National Center for Packaging Material Quality Supervision and Inspection, Chengdu Institute of Product Quality Supervision and Inspection, Chengdu 610064 (China); Meng, Xiang-Guang, E-mail: mengxgchem@163.com [Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China); Fu, Jing-Wei [National Center for Packaging Material Quality Supervision and Inspection, Chengdu Institute of Product Quality Supervision and Inspection, Chengdu 610064 (China); Yang, Yu-Chong; Yang, Peng; Mi, Chun [Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China)

    2014-02-15

    A novel chemically modified chitosan CS-SA-CD with phenol and β-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer–Emmett–Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m{sup 2}/g), pore volume (7.29 × 10{sup −3} mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m{sup 2}/g, 2.00 × 10{sup −3} mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and -OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80–91% adsorption efficiency.

  20. Efficient biodegradation of chlorophenols in aqueous phase by magnetically immobilized aniline-degrading Rhodococcus rhodochrous strain

    OpenAIRE

    Hou, Jianfeng; Liu, Feixia; Wu, Nan; Ju, Jiansong; Yu, Bo

    2016-01-01

    Background Chlorophenols are environmental contaminants, which are highly toxic to living beings due to their carcinogenic, mutagenic and cytotoxic properties. Bacterial degradation has been considered a cost-effective and eco-friendly method of removing chlorophenols, compared to the traditional physical–chemical processes. Results In this study, we first developed an efficient process for the biodegradation of chlorophenols by magnetically immobilized Rhodococcus rhodochrous cells. R. rhodo...

  1. Gamma Radiolytic Degradation of 4-Chlorophenol Determination of Degraded Products with HPLC and GC-MS

    OpenAIRE

    S. Bilal Butt; M. Nasir Masood; Nasir Hayat Hengra; M. Mansha Ch

    2007-01-01

    Contamination by chlorophenols of surface water and groundwater is an emerging issue in environmental science and engineering. After their usage as pesticide, herbicide and disinfectant, these organic compounds subsequently enter the aquatic environment through a number of routes. Some of the chlorophenols are slightly biodegradable, while others are more persistent and mobile in the aquatic environment especially chlorophenols. Gamma radiolytic degradation is one of advance oxidation process...

  2. Adsorption of Phenols and Chlorophenols in Wastewaters on Activated Carbon and Dried Activated Sludge

    OpenAIRE

    YENER, Jülide

    1999-01-01

    One of the methods used for removal of phenols and chlorophenols from the wastewaters of petroleum refineries, coke, medicine, dye, plastics, pesticide, insecticide, and paper industry is the adsorption process. In this study, adsorption of phenol, o-chlorophenol and p-chlorophenol from aqueous solutions on to granular activated carbon and dried activated sludge was investigated as a function of pH, initial pollutant concentration and functional groups. Effects of these parameters on...

  3. Raman and Surface-enhanced Raman Scattering of Chlorophenols

    Institute of Scientific and Technical Information of China (English)

    SONG Wei; SHANG Xiao-hong; LU Yong; LIU Bing-bing; WANG Xu

    2011-01-01

    Raman spectrum is a powerful analytical tool for determining the chemical information of compounds.In this study,we obtained analytical results of chlorophenols(CPs) molecules including 4-chlorophenol(4-CP),2,6-dichlorophenol(2,6-DCP) and 2,4,6-trichlorophenol(2,4,6-TCP) on the surface of Ag dendrites by surface-enhanced Raman scattering(SERS) spectra.SEM images indicate that the SERS substrate of Ag dendrites is composed of a large number of polygonal nanocrystallites,which self-assembled into a 3D hierarchical structure.It was found that there were distinct differences for those three molecules from Raman and SERS spectra.This indicates that SERS could be a new tool of detection technique regarding trace amounts of CPs.

  4. Degradability of chlorophenols using ferrate(VI) in contaminated groundwater.

    Science.gov (United States)

    Homolková, M; Hrabák, P; Kolář, M; Černík, M

    2016-01-01

    The production and use of chlorophenolic compounds in industry has led to the introduction of many xenobiotics, among them chlorophenols (CPs), into the environment. Five CPs are listed in the priority pollutant list of the U.S. EPA, with pentachlorophenol (PCP) even being proposed for listing under the Stockholm Convention as a persistent organic pollutant (POP). A green procedure for degrading such pollutants is greatly needed. The use of ferrate could be such a process. This paper studies the degradation of CPs (with an emphasis on PCP) in the presence of ferrate both in a spiked demineralized water system as well as in real contaminated groundwater. Results proved that ferrate was able to completely remove PCP from both water systems. Investigation of the effect of ferrate purity showed that even less pure and thus much cheaper ferrate was applicable. However, with decreasing ferrate purity, the degradability of CPs may be lower. PMID:26370812

  5. QSBR Study on the Anaerobic Biodegradation of Chlorophenols

    Institute of Scientific and Technical Information of China (English)

    YANG Da-Sen; DAI You-Zhi; LI Jian-Hua; ZHU Fei

    2006-01-01

    18 Physicochemical and quantum chemical parameters of 12 kinds of chlorophenols are calculated in this paper. QSBR (quantitative structure-biodegradability relationship) study is performed using simca statistical software by PLS regression analysis method on anaerobic biodegradation data (logKb), and the QSBR model is developed with favorable prediction. The model shows that the size and energy of the molecule are the dominant factors affecting the anaerobic biodegradation of chlorophenols. And the degradation rate constants (logKb) increase with the increase of core-core repulsion (CCR), average molecular polarizability (α), total surface area (TSA), heat of formation (HOF) and total energy (TE), while decrease with the increase of molecular connectivity index (1XV), relative molecular mass (Mw) and electronic energy (EE).

  6. Diffusion coefficients of chlorophenols in water by computer simulation

    OpenAIRE

    Parreira, M. Cristina B.; Ramalho, João P. P.; Carvalho, Afredo J. P.; Morgado, Pedro; Filipe, Eduardo. J. M.

    2013-01-01

    Cholophenols have found extensive industrial applications as wood preservatives or intermediated compounds for pesticide synthesis, and are also by-products of wood pulp bleaching processes [1]. As a result, they are nowadays common natural water contaminants, being considered priority substances by recent European Directives for Environmental Protection, due to their toxicity and persistence. The establishment of theoretical models to study environmental fate of chlorophenols is an important...

  7. Limited degradation of chlorophenols by anaerobic sludge granules.

    OpenAIRE

    Mohn, W W; Kennedy, K J

    1992-01-01

    To better understand the fate of chlorophenols treated in upflow anaerobic sludge bed reactors, we examined the ability of sludge granules from such bioreactors to degrade two trichlorophenols and one dichlorophenol in batch incubations under controlled conditions. Biodegradation was primarily limited to two distinct activities, reductive dehalogenation of ortho- and of meta-chlorine substituents. Both 3- and 4-monochlorophenol were persistent degradation products, while 2-monochlorophenol wa...

  8. In vitro and in silico investigations of the binding interactions between chlorophenols and trypsin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan-Qing, E-mail: wyqing76@126.com [Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, Yancheng City 224002, Jiangsu Province (China); Institute of Applied Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City 224002, Jiangsu Province (China); Tan, Chun-Yun [Institute of Applied Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City 224002, Jiangsu Province (China); Zhuang, Shu-Lin [Institute of Environmental Science, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058 (China); Zhai, Peng-Zhan; Cui, Yun; Zhou, Qiu-Hua; Zhang, Hong-Mei [Institute of Applied Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City 224002, Jiangsu Province (China); Fei, Zhenghao [Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection, Yancheng City 224002, Jiangsu Province (China); Institute of Applied Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City 224002, Jiangsu Province (China)

    2014-08-15

    Graphical abstract: - Highlights: • Binding interactions of five chlorophenols with trypsin were investigated. • The number of chlorine atoms of chlorophenols partly affected the binding ability of them to trypsin. • Noncovalent interactions stabilized the trypsin–chlorophenols complexes. • There was the one main binding site of trypsin for chlorophenols. - Abstract: Being the first-degree toxic pollutants, chlorophenols (CP) have potential carcinogenic and mutagenic activity and toxicity. Since there still lacks studies on molecular interactions of chlorophenols with trypsin, one major binding target of many exogenous environmental pollutants, the binding interactions between five chlorophenols, 2-CP, 2,6-DCP, 2,4,6-TCP, 2,4,6-TCP, 2,3,4,6-TCP and PCP and trypsin were characterized by the combination of multispectroscopic techniques and molecular modeling. The chlorophenols bind at the one main site of trypsin and the binding induces the changes of microenvironment and global conformations of trypsin. Different number of chloride atoms significantly affects the binding and the binding constants K{sub A} ranks as K{sub A} (2-CP) < K{sub A} (2,6-DCP) ≈ K{sub A} (2,4,6-TCP) < K{sub A} (2,3,4,6-TCP) < K{sub A} (PCP). These chlorophenols interacts with trypsin mainly through hydrophobic interactions and via hydrogen bonding interactions and aromatic–aromatic π–π stacking interaction. Our results offer insights into the binding mechanism of chlorophenols with trypsin and provide important information for possible toxicity risk of chlorophenols to human health.

  9. Study on US/O3 mechanism in p-chlorophenol decomposition

    Institute of Scientific and Technical Information of China (English)

    XU Xian-wen; XU Xin-hua; SHI Hui-xiang; WANG Da-hui

    2005-01-01

    Study on the effects of sonolysis, ozonolysis and US/O3 system on the decomposition ofp-chlorophenol in aqueous solutions indicated that in the cases of US/O3 system, individual ozonolysis and sonolysis, the decomposition rate of p-chlorophenol reached 78.78%, 56.20%, 2.79% after a 16-min reaction while its CODcr (chemical oxygen demand) removal rate was 97.02%, 62.17%, 3.67% after a 120-min reaction. The decomposition reaction ofp-chlorophenol follows pseudo-first-order kinetics. The enhancement factors ofp-chlorophenol and its CODer under US/O3 system reached 63% and 237% respectively. The main intermediates during the decomposition include catechol, hydroquinone, p-benzoquinone, phenol, fumaric acid, maleic acid,oxalic acid and formic acid. The decomposition mechanism of p-chlorophenol was also discussed.

  10. Fe salts as catalyst for the wet oxidation of o-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    XU Xin-hua; HE Ping; JIN Jian; HAO Zhi-wei

    2005-01-01

    Catalytic wet air oxidation (CWAO) of o-chlorophenol in wastewater was studied in a stainless steel autoclave using four different Fe catalysts in the temperature range of 100-200 ℃. Experimental results showed that high rate of o-chlorophenol and CODcr (Chemical Oxygen Demand, mg/L) removal by CWAO was obtained at relatively low temperature and pressure. The catalysts Fe2(SO4)3, FeSO4, Fe2O3 and FeCl3 all exhibited high catalytic activity. More than 93.7% of the initial CODCr and nearly100% of o-chlorophenol were removed at 150 ℃ after 150 min with FeSO4 as catalyst. The CWAO of o-chlorophenol was found to be pseudo-first order reaction with respect to o-chlorophenol, with activation energy of 75.56 k J/mol in the temperature range of100-175 ℃.

  11. Toxicological Profile of Chlorophenols and Their Derivatives in the Environment: The Public Health Perspective

    Directory of Open Access Journals (Sweden)

    Etinosa O. Igbinosa

    2013-01-01

    Full Text Available Chlorophenol compounds and their derivatives are ubiquitous contaminants in the environment. These compounds are used as intermediates in manufacturing agricultural chemicals, pharmaceuticals, biocides, and dyes. Chlorophenols gets into the environment from a variety of sources such as industrial waste, pesticides, and insecticides, or by degradation of complex chlorinated hydrocarbons. Thermal and chemical degradation of chlorophenols leads to the formation of harmful substances which constitute public health problems. These compounds may cause histopathological alterations, genotoxicity, mutagenicity, and carcinogenicity amongst other abnormalities in humans and animals. Furthermore, the recalcitrant nature of chlorophenolic compounds to degradation constitutes an environmental nuisance, and a good understanding of the fate and transport of these compounds and their derivatives is needed for a clearer view of the associated risks and mechanisms of pathogenicity to humans and animals. This review looks at chlorophenols and their derivatives, explores current research on their effects on public health, and proffers measures for mitigation.

  12. Photocatalytic efficiency of iron oxides: Degradation of 4-chlorophenol

    Science.gov (United States)

    Bakardjieva, Snejana; Stengl, Vaclav; Subrt, Jan; Houskova, Vendula; Kalenda, Petr

    2007-05-01

    The photocatalytic activity of ferrihydrite Fe5O7(OH)×4H2O synthesized by homogeneous precipitation with urea and products obtained by calcinations of as-precipitated ferrihydrite at different temperatures (200 1000 °C) was studied. The microstructure and surface properties of raw precipitate and all heated samples were characterized by means of HRTEM, SEM, BET/BJH and RTG analyses. Kinetics of disappearance of 4-chlorophenol (4-CP) in aqueous solution was used as a test reaction. We have found that hematite Fe2O3 obtained at 1000 °C exhibited satisfied photocatalytic efficiency on the degradation of 4-CP.

  13. Detection of Chlorophenolic Compounds in Bleaching Effluents of Chemical Pulps

    Institute of Scientific and Technical Information of China (English)

    Chhaya Sharma; S.Mohanty; S.Kumar; N.J.Rao; li qian

    2008-01-01

    Laboratory bleaching effluents from the chlorination and caustic extraction stages of mixed wood kraft pulp processing have been analysed both qualitatively and quantitatively for various chlorophenolics by using GC.A number of chlorinated derivaties of phenols,catechols,guaiacols and syringaldehydes have been detected and their concentrations are estimated.The results are compared with that of different agriculture residue / hardwood pulps,which were reported in literature.The concentrations of various compounds detected have also been compared with their reported 96LC50 values.

  14. Sonoelectrochemical fabrication of Pd-graphene nanocomposite and its application in the determination of chlorophenols

    Energy Technology Data Exchange (ETDEWEB)

    Shi Jianjun [Key Laboratory of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001 (China); Zhu Junjie, E-mail: jjzhu@nju.edu.cn [Key Laboratory of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    2011-07-01

    Highlights: > A novel nanocomposite with 3D Pd NPs on the graphene was fabricated via sonoelectrochemistry. > The Pd-graphene nanocomposite had high electrocatalytic activity for chlorophenols oxidation. > An electrochemical sensor for chlorophenols was constructed. > Ionic liquid was chosen as linker to show an enhanced effect on the electrocatalysis. - Abstract: A novel electrochemical sensor for chlorophenols was fabricated by using the Pd-graphene nanocomposite and ions liquid. The Pd-graphene nanocomposite was prepared via a sonoelectrochemical route, and the possible formation mechanism was proposed. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Raman spectrum were used for the characterization of structure and morphology of the nanocomposite. The experimental results showed that Pd nanospheres comprised of small Pd nanoparticles were uniformly attached on graphene sheets. The electrocatalytic properties were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which indicated that the Pd-graphene nanocomposite had high activity for chlorophenol oxidation. Herein, 2-chlorophenol was selected as the model molecules. The results showed that graphene played an important role in the fabrication of the chlorophenols sensor. The nanocomposite with large electrochemical active surface led to the excellent electrocatalytic activity, and ionic liquid further enhanced the catalytic activity of Pd-graphene for chlorophenols.

  15. Direct Photolysis of Chlorophenols In Aqueous Solution By Ultraviolet Excilamps

    Science.gov (United States)

    Matafonova, Galina; Philippova, Natalya; Batoev, Valeriy

    2011-08-01

    The direct photolysis of 2-chlorophenol (2-CP), 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) in model aqueous solution was studied using UV XeBr (282 nm) and KrCl (222 nm) excilamps. The highest pseudo-first order rate constants and quantum yields were found for molecular form of 4-CP (at pH 2 and 5.7) and anionic forms of 2-CP and 2,4-DCP (at pH 11) when irradiated by XeBr excilamp. The maximum removal efficiency of molecular form of 2-CP and 2,4-DCP with the lowest UV dose of absorbed energy was observed using KrCl excilamp. On the contrary, the XeBr excilamp required the lowest dose (˜2 Jṡcm-2) for complete degradation of molecular 4-CP and anionic 2-CP. The highest removal efficiency of anionic form of 4-CP (65%) was achieved when using KrCl excilamp.

  16. DECHLORINATION ACTIVITY (CROSS-ACCLIMATION) OF FRESHWATER SEDIMENTS ADAPTED TO MONO- AND DI-CHLOROPHENOLS

    Science.gov (United States)

    The reductive dechlorination of chlorophenols (CPs) in sediment slurries (10% solids) adapted to dechlorinate mono- and di-CPs (DCP) was investigated to define the regiospecificity of the dechlorination reaction. nadapted sediment slurries amended with various ortho-substituted C...

  17. Oxidation of phenol and chlorophenols on platinized titanium anodes in an acidic medium

    Science.gov (United States)

    Mokbel, Saleh Mohammed; Kolosov, E. N.; Mikhalenko, I. I.

    2016-06-01

    A comparative study of oxidation of phenol, 3-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol on Pt/Ti and Ce,Pt/Ti electrocatalysts is performed via cyclic voltammetry. It is shown that the surface morphology and roughness of the anode do not change after modification with cerium. The formal kinetic orders of electrooxidation of all compounds are found to be less than one. It is shown that the β temperature coefficients of the rate of oxidation of chlorophenols grow by 10 to 50% when the Ce,Pt/Ti anode is used at a substrate concentration of 1 mM. A tenfold increase in concentration reduces the effect of cerium additive, except for 3-chlorophenol: the latter exhibits a 250% increase in the β value, compared to the Pt/Ti anode.

  18. At-line testing of chlorophenol and chloroanisole contaminants in commercial wine production.

    OpenAIRE

    Nicholls, C. R.

    2004-01-01

    The research described in this thesis concerns the development of at-line test procedures for the detection of trace levels of chlorophenols and chloroanisoles in wine and related materials. Competitive ELISA assays were developed and optimised for pentachlorophenol and pentachloroanisole to enable the detection of chlorophenols and chloroanisoles in the range 0.1 to 100ng/ml in purified sample extracts, using antibodies supplied by the French consortium partner, Diaclone, together with s...

  19. Evaluation of removal efficiency of 2-chlorophenol in aquatic environments by modified fly ash

    OpenAIRE

    Mohammad Malakootian; Alireza Mesdaghinia; Shima Rezaei

    2015-01-01

    Background: Chlorophenols are classified as priority toxic pollutants. These acidic organic compounds present a serious potential hazard for human health and aquatic life. Chlorophenols accumulate in water, soil and air due to high stability, and impart an unpleasant taste and odor to drinking water and can exert negative effects on different biological processes. Among the different methods of removal, adsorption process by low price adsorbents, such as fly ash (FA) is common. Therefore, in ...

  20. Photocatalytic degradation of chlorophenols using Ru(bpy) 32+ /S2O 82-

    OpenAIRE

    M Silva; Burrows, H.; Formosinho, S.; Alves, L.; Godinho, A; Antunes, M.; Ferreira, D

    2007-01-01

    Abstract Advanced oxidation processes, such as photocatalysed oxidation, provide an important route for degradation of wastes. In this study, the lowest excited state (3MLCT) of Ru(bpy)32+ is used to break down chlorophenol pollutant molecules to harmless products. This has the advantage of using visible light and a short-lived catalytically active species. Photolysis of deaerated aqueous solutions of a variety of mono- and poly-substituted chlorophenols has been followed in the presence of ...

  1. EFFECTS OF 4-CHLOROPHENOL LOADINGS ON ACCLIMATION OF BIOMASS WITH OPTIMIZED FIXED TIME SEQUENCING BATCH REACTOR

    Directory of Open Access Journals (Sweden)

    H. Movahedyan, A. Assadi, M. M. Amin

    2008-10-01

    Full Text Available Abstract: Chlorinated phenols in many industrial effluents are usually difficult to be removed by conventional biological treatment processes. Performance of the aerobic sequencing batch reactor treating 4-chlorophenol containing wastewater at different loadings rates from 0.0075 to 1.2 g4CP/L.d was evaluated. The sequencing batch reactor was operated with fill, react, settle and decant phases in the order of 10:370:90:10 min, respectively, for a cycle time of 8 h at 10 days solid retention time and 16 h hydraulic retention time in the stable period. The effects of 4-chlorophenol loadings on the 4-chlorophenol and chemical oxygen demand removal percents, yield coefficient (Y, biomass variation and sludge volume index were investigated. High chemical oxygen demand removal efficiencies (95±3.5% and approximately complete 4-chlorophenol removal (>99% were observed even in the absence of growth substrate. The degradation of 4-chlorophenol led to formation of 5-chloro-2-hydroxymuconic semialdehyde, which was more oxidized, indicating complete disappearance of 4-chlorophenol via meta-cleavage pathway. A compact sludge with excellent settleability (sludge volume index=47±6.1 mL/g developed during entire acclimation period. High removal efficiencies with sequencing batch reactor may be due to enforced short term unsteady state conditions coupled with periodic exposure of the microorganisms to defined process conditions which facilitate the required metabolic pathways for treating xenobiotics containing wastewater.

  2. Degradation of chlorophenols in aqueous solution by {gamma}-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu Jun [INET, Tsinghua University, Beijing 100084 (China)]. E-mail: hujun@mail.tsinghua.edu.cn; Wang Jianlong [INET, Tsinghua University, Beijing 100084 (China)

    2007-08-15

    Degradation of chlorophenols (CPs) in aqueous solutions by {gamma}-radiation was studied. The effect of absorbed dose on degradation, dechlorination and mineralization of CPs were investigated. The results indicated that the degradation of CPs, Cl{sup -} release and mineralization increased with increase in absorbed dose. When the initial concentration was 100 mg L{sup -1} and the dosage was 6 kGy, the removal efficiencies of CPs were 44.54% for 2-CP, 91.46% for 3-CP, 82.72% for 4-CP and 93.25% for 2,4-DCP, respectively. The combination of irradiation and H{sub 2}O{sub 2} leads to a synergistic effect, which remarkably increased the degradation efficiency of CPs and TOC removal. The kinetics of CPs during irradiation are also mentioned.

  3. Volatile halogenated compounds and chlorophenols in the Skagerrak

    Science.gov (United States)

    Abrahamsson, Katarina; Ekdahl, Anja

    1996-02-01

    A total of 680 seawater samples were collected and analysed for volatile halogenated organic compounds, and 280 seawater samples were analysed for chlorinated phenols in the Skagerrak. The sampling was done along three transects along the Danish west coast on five occasions during the years 1991 to 1993. Pentachlorophenol (PCP) was the only chlorophenol detected on all occasions, which implies that it is transported as a dissolved species rather than particle bound. The results indicate that the origin of PCP in the Skagerrak is the Baltic and the coastal areas of Sweden and Norway. The biogenic volatile halocarbons constitute the largest fraction of the halocarbons in the area. The data support the findings that volatile chloroethenes are naturally produced. Therefore, the Skagerrak acts as a source for these compounds. The flux of the compounds investigated is directed from the sea to the atmosphere except for carbon tetrachloride.

  4. Degradation of chlorophenols in aqueous solution by γ-radiation

    Science.gov (United States)

    Hu, Jun; Wang, Jianlong

    2007-08-01

    Degradation of chlorophenols (CPs) in aqueous solutions by γ-radiation was studied. The effect of absorbed dose on degradation, dechlorination and mineralization of CPs were investigated. The results indicated that the degradation of CPs, Cl - release and mineralization increased with increase in absorbed dose. When the initial concentration was 100 mg L -1 and the dosage was 6 kGy, the removal efficiencies of CPs were 44.54% for 2-CP, 91.46% for 3-CP, 82.72% for 4-CP and 93.25% for 2,4-DCP, respectively. The combination of irradiation and H 2O 2 leads to a synergistic effect, which remarkably increased the degradation efficiency of CPs and TOC removal. The kinetics of CPs during irradiation are also mentioned.

  5. Reductive Dechlorination of p-Chlorophenol by Nanoscale Iron

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe0 under different conditions.Methods Nanoscale Fe0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope (ESEM).Results The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate,whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover,the stability and durability of nanoscale Fe0 was evaluated through batch studies over extended periods of time.Conclusion The nanoscale Fe0 can be used for sustainable treatment of contaminants in groundwater.

  6. Dechlorination of chlorophenols using magnesium-palladium bimetallic system

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Upendra D. [Centre of Environmental Science and Engineering, Indian Institute of Technology-Bombay, Mumbai 400076 (India)]. E-mail: upendra@iitb.ac.in; Suresh, Sumathi [Centre of Environmental Science and Engineering, Indian Institute of Technology-Bombay, Mumbai 400076 (India)]. E-mail: sumathis@iitb.ac.in

    2007-08-17

    Ninety-four percent removal of 10 mg L{sup -1} of pentachlorophenol (PCP) was achieved by treatment with 154.5 mM Mg{sup 0} and 0.063 mM K{sub 2}PdCl{sub 6} in the presence of 175 mM acetic acid in 1 h reaction time. Dechlorination of PCP was found to be sequential and phenol was identified as the end product along with accumulation of trace concentrations of tetra- and trichlorophenols. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) revealed that palladium in its metallic form (Pd{sup 0}) produced by reduction of Pd{sup 4+}, was spatially separated from magnesium granules when acid was included in the reaction. These colloidal palladium particles generated active reductive species of hydrogen and dechlorinated chlorophenols. In the absence of acid, the efficiency of dechlorination of PCP by Pd/Mg{sup 0} system was very low and chief mechanism of removal of the compound was through sorption onto solid surfaces. Thus, it was important to include acid in the system to: (a) facilitate corrosion of Mg{sup 0} and reduction of Pd{sup 4+} to Pd{sup 0}, (b) provision of protons to produce H{sub 2}, (c) retard formation of insoluble oxides and hydroxides that may deposit on the magnesium granules and sorb PCP and its partially dechlorinated products and. Application of 154.5 mM Mg{sup 0}/0.063 mM K{sub 2}PdCl{sub 6} on PCP, 2,4,5-trichlorophenol (TCP) and 2-chlorophenol (MCP) with organic chloride equivalence showed that the rate and extent of removal increased with decrease in number of chlorine atoms on phenol.

  7. Theoretical evidence of the Ni(III) participation in the chlorophenol oxidation on tetrasulphonated nickel phthalocyanine

    Science.gov (United States)

    Cárdenas-Jirón, Gloria I.; Berríos, Cristhian

    A theoretical methodology at B3LYP/LACVP(d)++ level for describing the oxidation of six chlorophenols (CP) on a nickel tetrasulphonated phthalocyanine (NiTSPc) is presented. The chlorophenols studied are: 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-CP), 2,6-dichlorophenol (2,6-CP), 2,4,6-trichlorophenol (2,4,6-CP), and pentachlorophenol (P-CP). On the basis of the experimental facts obtained by cyclic voltammetry, where the CP oxidation was carried out on poly-NiTSPc modified glassy carbon electrodes, the different stages (A-D) produced along the oxidation-reduction process were characterized at theoretical level, thereby obtaining their molecular and electronic structures. We found that the stage C, represented by the interaction of a chlorophenol anion with the Ni(III) complex shows, except in 2,4-CP and P-CP, the CP oxidation in all chlorophenols. These results predict Ni(III) to be the oxidation state that produce the oxidation of chlorophenol, in complete agreement with the experimental results. Natural bond analysis gives evidence for explaining why 2,4-CP and P-CP do not show a CP oxidation. A strong delocalization toward a alpha-carbon of the phenolic ring from a beta-carbon (206.31 kcal/mol for 2,4-CP, 200.66 kcal/mol for P-CP) and from the oxygen atom (58.67 kcal/mol for 2,4-CP, 83.91 kcal/mol for P-CP) seems to be the responsible for avoiding the CP oxidation with the Ni(III) complex.

  8. Comparative study on electrochemical degradation of 4-chlorophenol by different Pd/C gas diffusion electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG; Hui; WANG; JianLong

    2007-01-01

    Pd/C catalyst used for the Pd/C gas diffusion cathodes was prepared by hydrogen reduction method and formaldehyde reduction method, and characterized by X-ray diffraction (XRD), transmission electrode microcopy (TEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The electrochemical degradation of 4-chlorophenol was investigated in the diaphragm electrolysis system, aerating firstly with hydrogen gas then with air, using three different kinds of gas diffusion cathode. The results indicated that the self-made Pd/C gas diffusion cathode can not only reductively dechlorinate 4-chlorophenols by aerating hydrogen gas, but also accelerate the two-electron reduction of O2 to hydrogen peroxide (H2O2) by aerating air. Therefore, the removal efficiency of 4-chlorophenol by using Pd/C gas diffusion cathode is better than that of the C/PTFE gas diffusion cathode (no catalyst). The catalytic activity of Pd/C catalyst prepared by hydrogen reduction method is higher than that prepared by formaldehyde reduction method. The stability of the Pd/C gas diffusion cathodes is good. Therefore, both the removal efficiency and the dechlorination degree of 4-chlorophenol reached about 100% after 60 min, and the removal efficiency of 4-chlorophenol in terms of chemical oxygen demand (COD) in the cathodic compartment reached 87.4% after 120 min.

  9. Fluorescent Sensing of Chlorophenols in Water Using an Azo Dye Modified β-Cyclodextrin Polymer

    Directory of Open Access Journals (Sweden)

    Bhekie B. Mamba

    2011-04-01

    Full Text Available A water soluble azo dye modified β-cyclodextrin polymer 4 was synthesized and used as a chemosensor for the detection of chlorinated phenols, model chlorinated by-products (CBPs of water treatment for drinking purposes. The characterization of the intermediates and the azo dye modified β-CD polymer was done by UV/Vis Spectrophotometry, FT-IR and 1H-NMR spectroscopies. The chlorophenols were capable of quenching the fluorescence of the polymer. The polymer showed greater sensitivity towards 2,4-dichlorophenol, with a sensitivity factor of 0.35 compared to 0.05 and 0.12 for phenol and 4-chlorophenol, respectively. The stability constants (Ks of the pollutants were also determined by the Benesi-Hildebrand method to be 2.104 × 103 M−1 for 2,4-dichlorophenol and 1.120 × 102 M−1 for 4-chlorophenol.

  10. Non-thermal plasma induced decomposition of 2-chlorophenol in water

    International Nuclear Information System (INIS)

    Application of non-thermal plasma produced by pulsed corona discharge in water for degradation of 2-chlorophenol has been investigated in reactor with the needle-plate geometry of electrodes. It was shown that decomposition of 2-chlorophenol by the discharge can be referred essentially to the oxidation by hydroxyl radical and it can be described by the first order kinetics. The complete removal of 500 μmol.l-1 2-chlorophenol by the discharge was attained in the presence of ferrous ions with the energy efficiency of 3.5 x 10 -3 μmol.J-1. Chlorohydroquinone, chlorobenzoquinone, 3-chlorocatechol and catechol were detected as the primary decomposition products (Authors)

  11. Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Li Ning [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Descorme, Claude [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)]. E-mail: claude.descorme@catalyse.cnrs.fr; Besson, Michele [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2007-07-31

    A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3 wt.% Ru/ZrO{sub 2}. 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3 wt.% Ru/ZrO{sub 2} is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393 K) and lower total pressure (3 MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect.

  12. Electrochemical degradation of 4-chlorophenol using a novel Pd/C gas-diffusion electrode

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui; Wang, Jianlong [Laboratory of Environmental Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2007-11-30

    Pd/C catalyst was prepared by hydrogen reduction method and used for the Pd/C gas-diffusion electrode. It was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) techniques. The electrochemical degradation of 4-chlorophenol was investigated in a diaphragm electrolysis device, by two different feeding gas modes, using the Pd/C gas-diffusion electrode and the carbon/polytetrafluoroethylene (C/PTFE) gas-diffusion electrode as a cathode, respectively. The results indicated that Pd particles with an average size of 4.0 nm were highly dispersed in the activated carbon with an amorphous structure; Pd content on the surface of the Pd/C catalyst reached 1.3 at.%. Furthermore, feeding with hydrogen gas firstly and then with air was in favor of improving 4-chlorophenol removal efficiency. The Pd/C gas-diffusion cathode can not only reductively dechlorinate 4-chlorophenols by feeding hydrogen gas, but also accelerate the two-electron reduction of O{sub 2} to hydrogen peroxide (H{sub 2}O{sub 2}) by feeding air. Therefore, the removal efficiency of 4-chlorophenol by using the Pd/C gas-diffusion cathode was better than that of the C/PTFE gas-diffusion cathode. And both the removal efficiency and the dechlorination degree of 4-chlorophenol reached about 100% after 60 min, and the average removal efficiency of 4-chlorophenol in terms of chemical oxygen demand (COD) exceeded 70% after 120 min. The analysis of high-performance liquid chromatography (HPLC) identified that phenol was the dechlorination product, and hydroquinone, benzoquinone, maleic, fumaric, crylic, malonic, oxalic, acetic and formic acids were the main oxidation intermediates. A reaction pathway involving all these intermediates was proposed. (author)

  13. Removal of Chlorophenols by Fungal Laccase in the Presence of Aromatic Alcohols

    OpenAIRE

    Jarosz-Wilkolazka, Anna; Leonowicz, Andrzej; Oga, Shoji

    2007-01-01

    The effect of aromatic alcohols, coniferyl, sinapyl, vanillyl and iso-vanillyl alcohols, on the removal of chlorinated phenols from water environment by fungal laccases from Cerrena unicolor and Rhizoctonia praticola was studied. In optimal conditions all tested alcohols removed about 30 to 60% of chlorophenols from the supernatant, compared to that of laccase alone. R. praticola at pH 7.0 significantly removed more chlorophenols from supernatant than in the case of C. unicolor at pH 5.5. The...

  14. Self-catalytic degradation of ortho-chlorophenol with Fenton's reagent studied by chemiluminescence

    Institute of Scientific and Technical Information of China (English)

    Zhen Lin; HuiChen; Yun Zhou; Nobuaki Ogawa; Jin-Ming Lin

    2012-01-01

    The degradation of ortho-chlorophenol using Fenton's reagent was studied by chemiluminescence(CL).Without a special CL reagent,a weak CL emission from the mixture of ferrous ion and hydrogen peroxide was observed at room temperature.The CL intensity was increased by the addition of ortho-chlorophenol into the mixed solution.When the temperature was raised to 65℃,the CL intensity was enhanced strongly.The CL mechanisms for the system H2O2-Fe2+ with and without ortho-chlorophenol were studied by examining the CL spectrum,gas chromatography-mass spectrometry and electron spin resonance spectrum.The effects of various free radical scavengers,surfactants and fluorescence compounds on the CL intensity were also investigated.A self-catalytic oxidation mechanism was proposed.The results showed that singlet oxygen was the main emitter for the system H2O2-Fe2+.The strong CL from the system H2O2-Fe2+-ortho-chlorophenol was due to singlet oxygen and electronically excited quinone.The benzenediol-like intermediate product formed during the phenol oxidation process greatly promoted the Fenton's reaction and led to higher CL intensity.Chemiluninescence is a novel approach for the investigation of the oxidation of some organic pollutants by Fenton's reagent.

  15. Gamma Radiolytic Degradation of 4-Chlorophenol Determination of Degraded Products with HPLC and GC-MS

    Directory of Open Access Journals (Sweden)

    S. Bilal Butt

    2007-12-01

    Full Text Available Contamination by chlorophenols of surface water and groundwater is an emerging issue in environmental science and engineering. After their usage as pesticide, herbicide and disinfectant, these organic compounds subsequently enter the aquatic environment through a number of routes. Some of the chlorophenols are slightly biodegradable, while others are more persistent and mobile in the aquatic environment especially chlorophenols. Gamma radiolytic degradation is one of advance oxidation process that has been thought to be one of the promising treatments to deal with this problem. This radiolytic study was carried out in methanolic 4-CP (4-chlorophenol samples. Among several factors effecting radiolytic degradation of 4-CP, dose and concentration are important that were evaluated under atmospheric conditions. A degradation yield (G –value for 4-CP of 0.38 and 1.35 was achieved in 20 and 100mg/dm3 solution. It was observed that degradation yield decreases with increasing 4-CP concentration. Gamma radiolysis produce free radicals in solvent which further react with 4-CP molecules to generate different products. The identification of degradation products was proposed using HPLC and GC-MS.

  16. DIOXIN AND FURAN FORMATION ON FLY ASH FROM A MIXTURE OF CHLOROPHENOLS

    Science.gov (United States)

    To establish the relationship between specific chlorophenol (CP) congener distributions and polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) products this work investigated the formation of PCDDs/Fs from different CP mixtures passed over fly ash under selected reaction ...

  17. METHOD FOR THE CONFIRMATION OF CHLOROPHENOLS IN HUMAN URINE BY LC WITH AN ELECTROCHEMICAL DETECTOR

    Science.gov (United States)

    A method is described for the confirmation of chlorophenols in human urine. A hydrolyzed urine sample is analyzed by both gas chromatography (GC), and liquid chromatography (LC) with electrochemical detection and the results compared. A discussion of these results, including fact...

  18. Development of a robust chromatographic method for the detection of chlorophenols in cork oak forest soils.

    Science.gov (United States)

    McLellan, Iain; Hursthouse, Andrew; Morrison, Calum; Varela, Adélia; Pereira, Cristina Silva

    2014-02-01

    A major concern for the cork and wine industry is 'cork taint' which is associated with chloroanisoles, the microbial degradation metabolites of chlorophenols. The use of chlorophenolic compounds as pesticides within cork forests was prohibited in 1993 in the European Union (EU) following the introduction of industry guidance. However, cork produced outside the EU is still thought to be affected and simple, robust methods for chlorophenol analysis are required for wider environmental assessment by industry and local environmental regulators. Soil samples were collected from three common-use forests in Tunisia and from one privately owned forest in Sardinia, providing examples of varied management practice and degree of human intervention. These provided challenge samples for the optimisation of a HPLC-UV detection method. It produced recoveries consistently >75% against a soil CRM (ERM-CC008) for pentachlorophenol. The optimised method, with ultraviolet (diode array) detection is able to separate and quantify 16 different chlorophenols at field concentrations greater than the limits of detection ranging from 6.5 to 191.3 μg/kg (dry weight). Application to a range of field samples demonstrated the absence of widespread contamination in forest soils at sites sampled in Sardinia and Tunisia. PMID:24092255

  19. Toxic effects of pollutants on the Mineralization of 4-chlorophenol and Benzoate in methanogenic river sediment

    NARCIS (Netherlands)

    van Beelen P; van Vlaardingen PLA

    1993-01-01

    The toxic effects of pollutants on the mineralization of 2 mug/l [U-14C] 4-chlorophenol and benzoate were studied in microcosms with methanogenic sediment from the Rhine river. In contrast with studies using a high substrate concentration no lag time was observed and the half-lives for 4-chlorophen

  20. Phytotoxicity of some chloroanilines and chlorophenols, in relation to bioavailability in soil

    NARCIS (Netherlands)

    Gestel, C.A.M. van; Adema, D.M.M.; Dirven- Breemen, E.M. van

    1996-01-01

    Soil adsorption and the effect of four chlorophenols and three chloroanilines on the growth of lettuce (Lactuca sativa) were determined in two soil types differing in organic matter content and pH. Adsorption increased with increasing organic matter content of the soils. Phytotoxicity, based on dose

  1. Gamma radiolytic degradation of 4-chlorophenol determination of degraded products with HPLC and GC-MS

    International Nuclear Information System (INIS)

    Contamination by chlorophenols of surface water and groundwater is an emerging issue in environmental science and engineering. After their usage as pesticide, herbicide and disinfectant, these organic compounds subsequently enter the aquatic environment through a number of routes. Some of the chlorophenols are slightly biodegradable, while others are more persistent and mobile in the aquatic environment especially chlorophenols. Gamma radiolytic degradation is one of advance oxidation process that has been thought to be one of the promising treatments to deal with this problem. This radiolytic study was carried out in methanolic 4-CP (4-chlorophenol) samples. Among several factors effecting radiolytic degradation of 4-CP, dose and concentration are important that were evaluated under atmospheric conditions. A degradation yield (G -value) for 4- CP of 0.38 and 1.35 was achieved in 20 and 100 mg/dm/sup 3/ solution. It was observed that degradation yield decreases with increasing 4-CP concentration. Gamma radiolysis produce free radicals in solvent which further react with 4-CP molecules to generate different products. The identification of degradation products was proposed using HPLC and GC-MS. (author)

  2. Development of a robust chromatographic method for the detection of chlorophenols in cork oak forest soils.

    Science.gov (United States)

    McLellan, Iain; Hursthouse, Andrew; Morrison, Calum; Varela, Adélia; Pereira, Cristina Silva

    2014-02-01

    A major concern for the cork and wine industry is 'cork taint' which is associated with chloroanisoles, the microbial degradation metabolites of chlorophenols. The use of chlorophenolic compounds as pesticides within cork forests was prohibited in 1993 in the European Union (EU) following the introduction of industry guidance. However, cork produced outside the EU is still thought to be affected and simple, robust methods for chlorophenol analysis are required for wider environmental assessment by industry and local environmental regulators. Soil samples were collected from three common-use forests in Tunisia and from one privately owned forest in Sardinia, providing examples of varied management practice and degree of human intervention. These provided challenge samples for the optimisation of a HPLC-UV detection method. It produced recoveries consistently >75% against a soil CRM (ERM-CC008) for pentachlorophenol. The optimised method, with ultraviolet (diode array) detection is able to separate and quantify 16 different chlorophenols at field concentrations greater than the limits of detection ranging from 6.5 to 191.3 μg/kg (dry weight). Application to a range of field samples demonstrated the absence of widespread contamination in forest soils at sites sampled in Sardinia and Tunisia.

  3. Distinctive sorption mechanisms of 4-chlorophenol with black carbons as elucidated by different pH.

    Science.gov (United States)

    Shih, Yang-hsin; Su, Yuh-fan; Ho, Ren-yu; Su, Po-hsin; Yang, Chien-ying

    2012-09-01

    Black carbon (BC) has been considered as an important sorbent in the environment in recent years due to its high sorption capacity and unique sorption behavior. Sorption characteristics of black carbons from two main sources were investigated to get a better understanding of organic chemical fate in the environment. The present study showed sorption mechanisms of 4-chlorophenol, a common organic contaminant in the surroundings, in two kinds of black carbons, soot surrogate (BC1) and environmental char (BC2) derived from rice straw. Sorption capacity of 4-chlorophenol was much higher in BC1 than on BC2 due to the larger surface area of BC1. However, the surface-area normalized sorption coefficients (sorption capacity per surface area) of BC2 were higher than those of BC1, indicating electrostatic attraction and actions of polar foundational groups on BC2 can react with 4-chlorophenol. With increasing temperature, sorption of BC1 decreased but the sorption of BC2 significantly increased at pH 10 and only slightly increased at pH 4. An exothermic sorption reaction was found for BC1; however, an endothermic reaction of chemical sorption occurred on BC2 at pH 10 due to the electrostatic attraction. At pH4, sorption capacity of BC2 decreased and the small positive sorption enthalpy indicated that less electrostatic attractions occurred because of the neutral form of 4-chlorophenol and the domination of mainly hydrophobic interactions. PMID:22842752

  4. Adsorption of chlorophenols from aqueous solutions by pristine and surface functionalized single-walled carbon nanotubes.

    Science.gov (United States)

    Ding, Han; Li, Xin; Wang, Jun; Zhang, Xiaojian; Chen, Chao

    2016-05-01

    The adsorption of six kinds of chlorophenols on pristine, hydroxylated and carboxylated single-walled carbon nanotubes (SWCNTs) has been investigated. Pseudo-first order and pseudo-second order models were used to describe the kinetic data. All adsorption isotherms were well fitted with Langmuir, Freundlich and Polanyi-Manes models, due to surface adsorption dominating the adsorption process. The close linear relationship between logKow and logKd suggested that hydrophobicity played an important role in the adsorption. The SWCNTs' adsorption capacity for chlorophenols was weakened by addition of oxygen-containing functional groups on the surface, due to the loss of specific surface area, the increase of hydrophilicity and the reduction of π-π interaction. The best adsorption capacity of pristine SWCNTs, SWCNT-OH and SWCNT-COOH for six chlorophenols varied from 19 to 84mg/g, from 19 to 65mg/g and from 17 to 65mg/g, respectively. The effect of pH on the adsorption of 2,6-dichlorophenol (2,6-DCP), was also studied. When pH is over the pKa of 2,6-dichlorophenol (2,6-DCP), its removal dropped sharply. When ionic strength increased (NaCl or KCl concentration from 0 to 0.02mmol/L), the adsorption capacity of 2,6-DCP on pristine SWCNTs decreased slightly. The comparison of chlorophenols adsorption by SWCNTs, MWCNTs and PAC was made, indicating that the adsorption rate of CNTs was much faster than that of PAC. The results provide useful information about the feasibility of SWCNTs as an adsorbent to remove chlorophenols from aqueous solutions. PMID:27155424

  5. Rapid dechlorination of chlorophenols in aqueous solution by [Ni|Cu] microcell

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Lifeng, E-mail: yinlifeng@gmail.com [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Dai, Yunrong, E-mail: daiyunrong@mail.bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Niu, Junfeng, E-mail: junfengn@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Bao, Yueping, E-mail: baoyueping@mail.bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Shen, Zhenyao, E-mail: zyshen@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Rapid dechlorination of chlorophenols in aqueous solution can be achieved by [Ni|Cu] mixture. Black-Right-Pointing-Pointer The decomposition rates of chlorophenols by [Ni|Cu] were decuple of that by [Fe|Ni], [Fe|Cu], [Zn|Cu], or [Sn|Cu]. Black-Right-Pointing-Pointer Ni{sup 0} acts as an indirect reductant and catalyst in dechlorination reaction. Black-Right-Pointing-Pointer The H* corridor mechanism from Ni to Cu is proposed based on hydrogen spillover. - Abstract: The [Ni|Cu] microcell was prepared by mixing the Ni{sup 0} and Cu{sup 0} particles. The composition and crystal form were characterized by X-ray diffraction (XRD) and scanning electron microscope. The results evidenced the zero-valence metals Ni and Cu were exposed on the surface of particles mixture. The [Ni|Cu] microcell was employed to decompose chlorophenols in aqueous solution by reductive dechlorination. The dechlorination rates of chlorophenols by [Ni|Cu] were >10 times faster than those by [Fe|Cu], [Zn|Cu], [Sn|Cu], and [Fe|Ni] mixtures under the same conditions. [Ni|Cu] is different from other zero valent metals (ZVMs) in that it performed the best at neutral pH. The main products of chlorophenol dechlorination were cyclohexanol and cyclohexanone. The reduction kinetics was between pseudo zero-order and first-order, depending on the pH, concentration, and temperature. These results, combined with electrochemical analysis, suggested that Ni{sup 0} acted as a reductant and catalyst in dechlorination reaction. The H* corridor mechanism from Ni{sup 0} to Cu{sup 0} was also proposed based on hydrogen spillover. The inhibition on the release of Ni{sup 2+} by adding natural organic matters and adjusting pH was investigated.

  6. TEMPERATURE AND CONCENTRATION EFFECTS ON THE DIOXIN AND FURAN FORMATION FROM A MIXTURE OF CHLOROPHENOLS OVER FLY ASH

    Science.gov (United States)

    Chlorophenols have been studied as precursors to PCDD/F formation but generally these experiments have been carried out with unrepresentative concentrations and potentially overlapping formation mechanisms. Research has demonstrated that the kinetics of PCDD formation from chloro...

  7. Interlaboratory validation of PrEN 12673: Water quality - Gas Chromatographic determination of some selected chlorophenols in water

    NARCIS (Netherlands)

    Hoogerbrugge R; Ramlal MR; Stil GH; Gort SM; Heusinkveld HAG; van der Velde EG; van Zoonen P; LOC

    1997-01-01

    Een interlaboratorium vergelijkingsonderzoek is georganiseerd ten behoeve van de validatie van de voorlopige standaard methode PrEN 12673 Water quality - Gas Chromatographic determination of some selected chlorophenols in water. Deze vergelijking is uitgevoerd op drie typen water, namelijk drinkwat

  8. Direct determination of chlorophenols in landfill leachates by solid-phase micro-extraction-gas chromatography-mass spectrometry

    OpenAIRE

    Ribeiro, A.; Neves, MH; de Almeida, MF; Alves, A.; Santos, L.

    2002-01-01

    Landfill leachates represent a serious environmental concern with regard to trace priority pollutants introduced into the aquatic environment. From the analytical point of view, they constitute complex matrices because of their high organic matter content and competition with the trace analytes in the extraction procedure. Although the use of SPME to extract chlorophenols in leachates has already been described in several publications, the limited number of chlorophenols restricts this analys...

  9. Malignant lymphoma and exposure to chemicals, especially organic solvents, chlorophenols and phenoxy acids: a case-control study.

    OpenAIRE

    Hardell, L; Eriksson, M.; Lenner, P; Lundgren, E.

    1981-01-01

    A number of men with malignant lymphoma of the histiocytic type and previous exposure to phenoxy acids or chlorophenols were observed and reported in 1979. A matched case-control study has therefore been performed with cases of malignant lymphoma (Hodgkin's disease and non-Hodgkin lymphoma). This study included 169 cases and 338 controls. The results indicate that exposure to phenoxy acids, chlorophenols, and organic solvents may be a causative factor in malignant lymphoma. Combined exposure ...

  10. Electrochemical Characterization and Determination of Phenol and Chlorophenols by Voltammetry at Single Wall Carbon Nanotube/Poly(3,4-ethylenedioxythiophene) Modified Screen Printed Carbon Electrode

    OpenAIRE

    Negash, Negussie; Alemu, Hailemichael; Tessema, Merid

    2015-01-01

    Screen printed carbon electrode (SPCE) has been modified with single wall carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) composites for the determination of phenol and chlorophenols (phenol, 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol). The effect of the modifiers on the electrode characteristics was evaluated and the responses were optimized for the voltammetric determination of phenol and chlorophenols. The parameters affecting the responses such as pH, sca...

  11. Electron-Transfer Oxidation of Chlorophenols by Uranyl Ion Excited State in Aqueous Solution. Steady-State and Nanosecond Flash Photolysis Studies

    OpenAIRE

    Sarakha, Mohamed; Bolte, Michèle; Burrows, Hugh D.

    2000-01-01

    The oxidation of chlorophenols by photoexcited uranyl ion was studied in aqueous solution at concentrations where the ground-state interactions were negligible. Nanosecond flash photolysis showed that a clean electron-transfer process from the chlorophenols to the excited uranyl ion is involved. This is suggested to lead to the formation of a U(V)/chlorophenoxyl radical pair complex. The efficiency of this charge-transfer process is unity for the three chlorophenols. However, low product yiel...

  12. 2-Chlorophenol Removal of Aqueous Solution Using Advanced Oxidation Processes Resulting from Iron/ Persulfate and Ultra Violet/ Persulfate

    Directory of Open Access Journals (Sweden)

    Shokufeh Astereki

    2016-06-01

    Full Text Available Background: Advanced oxidation processes are used to remove toxic aromatic compounds with low biodegradability, such as 2-chlorophenol. This study investigated the use of sulfate (SO4- and persulfate (S2O82- radicals, as one of the advanced oxidation methods, to remove 2- chlorophenol from aquatic solutions. Methods: This experimental and pilot-scale study was carried out using two chemical batch reactors; one of the reactors equipped with UV lamps and the other was on the hot plate. In iron/ persulfate (Fe/S2O82- and ultra violet/ persulfate (UV/S2O82- processes different parameters were investigated. Results: Iron, UV, the initial pH of the solution, persulfate concentration have considerable effects on the elimination of 2-chlorophenol in both processes. In both processes, the maximum elimination occurred in acidic conditions. The elimination efficiency was increased by increasing the concentration of 2-chlorophenol and UV intensity, and also by decreasing the concentration of persulfate and iron. Accordingly, in iron/ persulfate and ultra violet/ persulfate processes 2-chlorophenol was eliminated with 99.96% and 99.58% efficiencies, respectively. Conclusion: Sulfate radicals produced from activated persulfate ions with hot-Fe ion and UV radiation have significant impact on the removal of 2-chlorophenol. Therefore, the processes of Fe/S2O82- and UV/S2O82- can be regarded as good choices for industrial wastewater treatment plants operators in the future.

  13. Quantitative Analysis of the Relative Transcript Levels of Four Chlorophenol Reductive Dehalogenase Genes in Desulfitobacterium hafniense PCP-1 Exposed to Chlorophenols

    OpenAIRE

    Bisaillon, Ariane; Beaudet, Réjean; Lépine, François; Villemur, Richard

    2011-01-01

    Relative to those of unexposed cultures, the transcript levels of the four CprA-type reductive dehalogenase genes (cprA2, cprA3, cprA4, and cprA5) in Desulfitobacterium hafniense PCP-1 were measured in cultures exposed to chlorophenols. In 2,4,6-trichlorophenol-amended cultures, cprA2 and cprA3 were upregulated, as was cprA5, but concomitantly with the appearance of 2,4-dichlorophenol (DCP). In 3,5-DCP-amended cultures, only cprA5 was upregulated. In pentachlorophenol-amended cultures grown f...

  14. Study on the reaction of chlorophenols in room temperature ionic liquids with ionizing radiation

    Science.gov (United States)

    Kimura, Atsushi; Taguchi, Mitsumasa; Kondoh, Takafumi; Yang, Jinfeng; Yoshida, Yoichi; Hirota, Koichi

    2008-10-01

    The effects of cations and anions of room temperature ionic liquids (RTILs) on the decomposition of chlorophenols and formation of phenol were investigated by gamma and pulse radiolyses. Absorption bands were observed for aliphatic RTILs just after pulsed electron irradiation, and were assigned as solvated electrons. The decomposition yield of chlorophenol (CP), G(-CP), and the formation yield of phenol, G(Phenol), in RTILs, in which solvated electrons were observed, were higher than those in RTILs, in which the solvated electrons were not detected. G(-CP) and G(Phenol) increased with the viscosity of the RTILs which have diethylmethyl(2-methoxyethyl)ammonium (DEMMA) as cation. G(Phenol) in DEMMA-bis(trifluoromethylsulfonyl)imide (TFSI) having high viscosity was higher than that in trimethylpropylammonium (TMPA)-TFSI having low viscosity. The ratios of G(Phenol)/ G(-CP) were not affected by the substituted position of chlorine on CP in RTILs.

  15. Evaluation of toxicity and genotoxicity of 2-chlorophenol on bacteria, fish and human cells.

    Science.gov (United States)

    Vlastos, Dimitris; Antonopoulou, Maria; Konstantinou, Ioannis

    2016-05-01

    Due to the extensive use of chlorophenols (CPs) in anthropogenic activities, 2-Chlorophenol (2-CP), among other CPs, can enter aquatic ecosystems and can be harmful to a variety of organisms, including bacteria, fish and humans, that are exposed directly and/or indirectly to such contaminated environments. Based on the existing knowledge and in order to move a step forward, the purpose of this study is to investigate the toxic and mainly the genotoxic effects of 2-CP using a combination of bioassays. The tests include the marine bacterium Vibrio fischeri and micronuclei induction in the erythrocytes of Carassius auratus as well as in cultured human lymphocytes. The results obtained reveal that 2-CP is able to induce dose-dependent toxic and genotoxic effects on the selected tested concentrations under the specific experimental conditions. PMID:26897408

  16. Study on the reaction of chlorophenols in room temperature ionic liquids with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Atsushi [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)], E-mail: kimura.atsushi81@jaea.go.jp; Taguchi, Mitsumasa [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Kondoh, Takafumi; Yang, Jinfeng; Yoshida, Yoichi [Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka (Japan); Hirota, Koichi [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2008-10-15

    The effects of cations and anions of room temperature ionic liquids (RTILs) on the decomposition of chlorophenols and formation of phenol were investigated by gamma and pulse radiolyses. Absorption bands were observed for aliphatic RTILs just after pulsed electron irradiation, and were assigned as solvated electrons. The decomposition yield of chlorophenol (CP), G(-CP), and the formation yield of phenol, G(Phenol), in RTILs, in which solvated electrons were observed, were higher than those in RTILs, in which the solvated electrons were not detected. G(-CP) and G(Phenol) increased with the viscosity of the RTILs which have diethylmethyl(2-methoxyethyl)ammonium (DEMMA) as cation. G(Phenol) in DEMMA-bis(trifluoromethylsulfonyl)imide (TFSI) having high viscosity was higher than that in trimethylpropylammonium (TMPA)-TFSI having low viscosity. The ratios of G(Phenol)/G(-CP) were not affected by the substituted position of chlorine on CP in RTILs.

  17. Screening of a microbial consortium for highly simultaneous degradation of lignocellulose and chlorophenols.

    Science.gov (United States)

    Liang, Jiajin; Peng, Xiang; Yin, Dexing; Li, Beiyin; Wang, Dehan; Lin, Yunqin

    2015-08-01

    In this work, spent mushroom substrates were utilized for screening a microbial consortium with highly simultaneous degradation of lignocellulose and chlorophenols. The desired microbial consortium OEM1 was gained through successive cultivation for about 50 generations and its stability of composition was verified by denaturing gradient gel electrophoresis (DGGE) during screening process. It could degrade lignocellulose and chlorophenols at around 50% and 100%, respectively, within 7days. The diversity analysis and the growth characteristics of OEM1 during degradation process were investigated by PCR-DGGE combined with clone and sequence. The results indicated that OEM1 consisted of 31 strains. Proteobacteria and Bacteroidetes were the predominant bacterial groups. The dynamic change of OEM1 illustrated that consortium community structure was effected by pH and substrate alteration and tended to be stable after 6days' cultivation. Furthermore, bacteria (11 strains) and actinomycetes (2 strains) were obtained based on plate isolation and identified via 16S rDNA sequence. PMID:25974352

  18. Mathematical Model of In-situ Ozonation for the Remediation of 2-Chlorophenol Contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    张晖; 宋孟浩; 黄金宝

    2003-01-01

    A microscopic diffusion-reaction model was developed to simulate in-situ ozonation for the remediation of contaminated soil, i.e., to predict the temporal and spatial distribution of target contaminant in the subsurface.The sequential strategy was employed to obtain the numerical solution of the model using finite difference method. A non-uniform grid of discretization points was employed to increase the accuracy of the numerical solution by means of coordinate transformation. One-dimensional column tests were conducted to verify the model. The column was packed with simulated soils that were spiked with 2-chlorophenol. Ozone gas passed through the column at a flow rate of 100 ml·min-1. The residual 2-chlorophenol content at different depths of the column was determined at fixed time intervals. Compared the experimental data with the simulated values, it was found that the mathematical model fitted data well during most time of the experiment.

  19. Adsorbed states of chlorophenol on Cu(110) and controlled switching of single-molecule junctions

    Science.gov (United States)

    Okuyama, H.; Kitaguchi, Y.; Hattori, T.; Ueda, Y.; Ferrer, N. G.; Hatta, S.; Aruga, T.

    2016-06-01

    A molecular junction of substituted benzene (chlorophenol) is fabricated and controlled by using a scanning tunneling microscope (STM). Prior to the junction formation, the bonding geometry of the molecule on the surface is characterized by STM and electron energy loss spectroscopy (EELS). EELS shows that the OH group of chlorophenol is dissociated on Cu(110) and that the molecule is bonded nearly flat to the surface via an O atom, with the Cl group intact. We demonstrate controlled contact of an STM tip to the "available" Cl group and lift-up of the molecule while it is anchored to the surface via an O atom. The asymmetric bonding motifs of the molecule to the electrodes allow for reversible control of the junction.

  20. One-bath synthesis of hydrophilic molecularly imprinted quantum dots for selective recognition of chlorophenol

    Institute of Scientific and Technical Information of China (English)

    Tai Ye; Shi Yan Lu; Qin Qin Hu; Xin Jiang; Guo Fen Wei; Jing Jing Wang; Jian Quan Lu

    2011-01-01

    A simple one-bath strategy has been developed to synthesize a novel CdTe@SiO2@MIP (molecularly imprinted and silica-functionalized CdTe quantum dots, MISFQDs), in which a silica shell was coated on the surface of CdTe quantum dots (CdTe@SiO2 QDs) and then a polymer for selective recognition of 4-chlorophenol (4-CP) was constructed on the surface of CdTe@SiO2 QDs using mercaptoacetic acid as stabilizer, 3-aminopropyl-trimethoxysilane (APTES) as functional monomers and tetraethoxysilane (TEOS) as crosslink agent. The structures of CdTe@SiO2@MIP were analyzed by ultraviolet-visible absorption, Fluorescence, FT-IR spectrum and powder X-ray diffraction. The application and characterization of the CdTe@SiO2@MIP were investigated by experiments. All results indicated that the CdTe@SiO2@MIP can selectively recognize 4-chlorophenol.

  1. Purification and characterization of chlorophenol 4-monooxygenase from Burkholderia cepacia AC1100.

    OpenAIRE

    Xun, L

    1996-01-01

    Burkholderia (formerly Pseudomonas) cepacia AC1100 mineralizes the herbicide 2,4,5-trichlorophenoxyacetate (2,4,5-T), and the first intermediate of 2,4,5-T degradation is 2,4,5-trichlorophenol. Chlorophenol 4-monooxygenase activity responsible for 2,4,5-trichlorophenol degradation was detected in the cell extract. The enzyme consisted of two components separated during purification, and both were purified to more than 95% homogeneity. The reconstituted enzyme catalyzed the hydroxylation of se...

  2. Phenoxy herbicides and chlorophenols: a case control study on soft tissue sarcoma and malignant lymphoma.

    OpenAIRE

    Smith, J G; Christophers, A.J.

    1992-01-01

    A case control study on patients with soft tissue sarcoma and malignant lymphoma was undertaken to test whether there was any association between these diseases and past exposure to chlorinated phenoxy acid herbicides or chlorophenols. It was carried out over the period 1982-1988 in Victoria, Australia. Thirty males with soft tissue sarcoma and 52 males with malignant lymphoma were matched by age, place of residence and sex with one population control and one cancer control each. Exposure was...

  3. Prediction of Environmental Properties for Chlorophenols with Posetic Quantitative Super-Structure/Property Relationships (QSSPR)

    OpenAIRE

    Douglas J. Kleinc; Ovidiu Ivanciuc; Teodora Ivanciuc

    2006-01-01

    Due to their widespread use in bactericides, insecticides, herbicides, andfungicides, chlorophenols represent an important source of soil contaminants. Theenvironmental fate of these chemicals depends on their physico-chemical properties. In theabsence of experimental values for these physico-chemical properties, one can use predictedvalues computed with quantitative structure-property relationships (QSPR). As analternative to correlations to molecular structure we have studied the super-stru...

  4. The cooperative electrochemical oxidation of chlorophenols in anode-cathode compartments

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hui [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China); Wang Jianlong [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China)], E-mail: wangjl@tsinghua.edu.cn

    2008-06-15

    By using a self-made carbon/polytetrafluoroethylene (C/PTFE) O{sub 2}-fed as the cathode and Ti/IrO{sub 2}/RuO{sub 2} as the anode, the degradation of three organic compounds (phenol, 4-chlorophenol, and 2,4-dichlorophenol) was investigated in the diaphragm (with terylene as diaphragm material) electrolysis device by electrochemical oxidation process. The result indicated that the concentration of hydrogen peroxide (H{sub 2}O{sub 2}) was 8.3 mg/L, and hydroxyl radical (HO{center_dot}) was determined in the cathodic compartment by electron spin resonance spectrum (ESR). The removal efficiency for organic compounds reached about 90% after 120 min, conforming to the sequence of phenol, 4-chlorophenol, and 2,4-dichlorophenol. And the dechlorination degree of 4-chlorophenol exceeded 90% after 80 min. For H{sub 2}O{sub 2}, HO{center_dot} existed in the catholyte and reduction dechlorination at the cathode, the mineralization of organics in the cathodic compartment was better than that in the anodic compartment. The degradation of organics was supposed to be cooperative oxidation by direct or indirect electrochemical oxidation at the anode and H{sub 2}O{sub 2}, HO{center_dot} produced by oxygen reduction at the cathode. High-performance liquid chromatography (HPLC) allowed identifying phenol as the dechlorination product of 4-chlorophenol in the cathodic compartment, and hydroquinone, 4-chlorocatechol, benzoquinone, maleic, fumaric, oxalic, and formic acids as the main oxidation intermediates in the cathodic and anodic compartments. A reaction scheme involving all these intermediates was proposed.

  5. Determination of chlorophenols in environmental samples using electromembrane extraction and capillary electrophoresis

    OpenAIRE

    Šlampová, Andrea

    2013-01-01

    Combination of electromembrane extraction (EME) with capillary electrophoresis (CE) was used for determination of trace level chlorophenols (CPs) in environmental water samples. The analytes were transported across supported liquid membrane (SLM), composed of 1-ethyl-2-nitrobenzene (ENB), by the application of electrical field. A driving force of 150 V was applied to extract the analytes from neutral sample (donor solution) into strongly alkaline acceptor solutions. The acceptor soluti...

  6. Pentachlorophenol and Cancer Risk: Focusing the Lens on Specific Chlorophenols and Contaminants

    OpenAIRE

    Cooper, Glinda S.; Jones, Samantha

    2008-01-01

    Objective Pentachlorophenol, a fungicide widely used as a wood preservative, was classified in 1999 by the International Agency for Research on Cancer as a possible human carcinogen. We reviewed currently available data to determine the extent to which recent studies assist in distinguishing the effect of pentachlorophenol from that of its contaminants (e.g., dioxins and other chlorophenols). Data sources and extraction We performed a systematic review of published studies pertaining to cance...

  7. Transcriptional Regulation of the cpr Gene Cluster in ortho-Chlorophenol-Respiring Desulfitobacterium dehalogenans

    OpenAIRE

    Smidt, H.; Leest, de, H.T.J.I.; Oost, van der, J.; De Vos

    2000-01-01

    To characterize the expression and possible regulation of reductive dehalogenation in halorespiring bacteria, a 11.5-kb genomic fragment containing the o-chlorophenol reductive dehalogenase-encoding cprBA genes of the gram-positive bacterium Desulfitobacterium dehalogenans was subjected to detailed molecular characterization. Sequence analysis revealed the presence of eight designated genes with the order cprTKZEBACD and with the same polarity except for cprT. The deduced cprC and cprK gene p...

  8. COMPARISON OF DIFFERENT ADVANCED OXIDATION PROCESSES DEGRADING P-CHLOROPHENOL IN AQUEOUS SOLUTION

    Directory of Open Access Journals (Sweden)

    H. Movahedyan ، A. M. Seid Mohammadi ، A. Assadi

    2009-07-01

    Full Text Available In present study, degradation of p-chlorophenol using several oxidation systems involving advanced oxidation processes such as ultraviolet/H2O2, microwave/H2O2 and both in the absence of hydrogen peroxide in batch mode by photolytic pilot plant and modified domestic microwave oven was evaluated. The oxidation rate was influenced by many factors, such as the pH value, the amount of hydrogen peroxide, irradiation time and microwave power. The optimum conditions obtained for the best degradation rate were pH=7 and H2O2 concentration of 0.05 mol/L for ultraviolet/H2O2 system and pH=10.5, H2O2 concentration of about 0.1 mol/L and microwave irradiation power of about 600W for microwave/H2O2 system at constant p-chlorophenol concentration. The degradation of p-chlorophenol by different types of oxidation processes followed first order rate decay kinetics. The rate constants were 0.137, 0.012, 0.02 and 0.004/min1 for ultraviolet/H2O2, microwave/H2O2, ultraviolet and microwave irradiation alone. Finally a comparison of the specific energy consumption showed that ultraviolet/H2O2 process reduced the energy consumption by at least 67% compared with the microwave/H2O2 process.

  9. Quantitative structure activity relationship and toxicity mechanisms of chlorophenols on cells in vitro

    Institute of Scientific and Technical Information of China (English)

    JIANG Jie; CHEN Jiangning; YU Hongxia; ZHANG Feng; ZHANG Junfeng; WANG Liansheng

    2004-01-01

    3-(4,5-dimethylthiazd-2-yl)-2,5-diphenylentrazolium bromide (MTT) reduction assay was used to investigate the acute toxicity of 8 different chlorophenols (CPs) on rat connective tissue fibroblast L929 cells and human liver cancer HepG2 cells. Combined with the data from Quantitative Structure Activity Relationship (QSAR) approach of CPs by using the octanol-water partition coefficients (Kow), an effective model was deduced to evaluate the cytotoxicity of these chemicals. Furthermore, the relationship between the structures of CPs and their cytotoxicity was proposed. The results show that 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,6-dichlorophenol (2,6-DCP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and 2,3,4-trichlorophenol (2,3,4-TCP) induced apoptosis, whereas, 2,3,5,6-tetrachlorophenol (2,3,5,6-TeCP) and pentachlorophenl (PCP)demonstrated more characteristic of necrosis than apoptosis.These results establish a good experimental base both for developing the comparative evaluation of toxicity of CPs in vitro and for elucidating the toxicity mechanisms of them.

  10. Prediction of Environmental Properties for Chlorophenols with Posetic Quantitative Super-Structure/Property Relationships (QSSPR

    Directory of Open Access Journals (Sweden)

    Douglas J. Kleinc

    2006-09-01

    Full Text Available Due to their widespread use in bactericides, insecticides, herbicides, andfungicides, chlorophenols represent an important source of soil contaminants. Theenvironmental fate of these chemicals depends on their physico-chemical properties. In theabsence of experimental values for these physico-chemical properties, one can use predictedvalues computed with quantitative structure-property relationships (QSPR. As analternative to correlations to molecular structure we have studied the super-structure of areaction network, thereby developing three new QSSPR models (poset-average, cluster-expansion, and splinoid poset that can be applied to chemical compounds which can behierarchically ordered into a reaction network. In the present work we illustrate these posetQSSPR models for the correlation of the octanol/water partition coefficient (log Kow and thesoil sorption coefficient (log KOC of chlorophenols. Excellent results are obtained for allQSSPR poset models to yield: log Kow, r = 0.991, s = 0.107, with the cluster-expansionQSSPR; and log KOC, r = 0.938, s = 0.259, with the spline QSSPR. Thus, the poset QSSPRmodels predict environmentally important properties of chlorophenols.

  11. Preferential adsorption of pentachlorophenol from chlorophenols-containing wastewater using N-doped ordered mesoporous carbon.

    Science.gov (United States)

    Yang, Bin; Liu, Yunpeng; Li, Zhongjian; Lei, Lecheng; Zhou, Jie; Zhang, Xingwang

    2016-01-01

    Preferential removal of pentachlorophenol (PCP) from chlorophenols-containing wastewater has been attracted more attentions in wastewater treatment, since it is one of the most toxic pollutants. The adsorbent of N-doped ordered mesoporous carbon (M-OMC) with high BET surface area of 1901 m(2)/g, large pore volume of 1.64 cm(3)/g and uniform pore size of 3.45 nm has been successfully synthesized via evaporation-induced self-assembly (EISA) method. The effects of solution pH, pore structure of adsorbent and their surface chemical properties on PCP adsorption by M-OMC were investigated in comparison with ordered mesoporous carbon (OMC), and much higher PCP adsorption capacities of M-OMC were obtained. The significantly preferential adsorption of PCP was achieved in the treatment of tri-component wastewater including PCP, p-chlorophenol (CP) and 2.4.6-trichlorophenol (TCP), and its adsorption process well fitted the pseudo-second-order kinetics model and the Langmuir isotherm. The initial sorption rate of PCP was 103.5 μmol/(g/min), which was 2.97 times of TCP. It may be attributed to the intensification of π-π interaction between PCP and M-OMC with the nitrogen functional groups. Therefore, M-OMC is promising for removal of PCP in the adsorption pretreatment of chlorophenols-containing wastewater. PMID:26374540

  12. Emergent behaviour in a chlorophenol-mineralising three-tiered microbial ‘food web’

    Science.gov (United States)

    Wade, M.J.; Pattinson, R.W.; Parker, N.G.; Dolfing, J.

    2016-01-01

    Anaerobic digestion enables the water industry to treat wastewater as a resource for generating energy and recovering valuable by-products. The complexity of the anaerobic digestion process has motivated the development of complex models. However, this complexity makes it intractable to pin-point stability and emergent behaviour. Here, the widely used Anaerobic Digestion Model No. 1 (ADM1) has been reduced to its very backbone, a syntrophic two-tiered microbial ‘food chain’ and a slightly more complex three-tiered microbial ‘food web’, with their stability analysed as a function of the inflowing substrate concentration and dilution rate. Parameterised for phenol and chlorophenol degradation, steady-states were always stable and non-oscillatory. Low input concentrations of chlorophenol were sufficient to maintain chlorophenol- and phenol-degrading populations but resulted in poor conversion and a hydrogen flux that was too low to sustain hydrogenotrophic methanogens. The addition of hydrogen and phenol boosted the populations of all three organisms, resulting in the counterintuitive phenomena that (i) the phenol degraders were stimulated by adding hydrogen, even though hydrogen inhibits phenol degradation, and (ii) the dechlorinators indirectly benefitted from measures that stimulated their hydrogenotrophic competitors; both phenomena hint at emergent behaviour. PMID:26551153

  13. Thermal regeneration of activated carbons saturated with ortho- and meta-chlorophenols

    Energy Technology Data Exchange (ETDEWEB)

    Maroto-Valer, M. Mercedes [School of Chemical, Environmental and Mining Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Dranca, Ion; Clifford, David [The Energy Institute of the Penn State University, University Park, PA 16802 (United States); Lupascu, Tudor; Nastas, Raisa [Institute of Chemistry of the Academy of Sciences, Chisinau MD 2028 (Moldova, Republic of); Leon y Leon, Carlos A. [Quantachrome Instruments, Boynton Beach, FL 33426 (United States)

    2006-05-15

    Activated carbons (ACs) made from peach and plum stones were oxidized and impregnated with salts of Cu(II), Fe(III), Ni(II) and Cr(III). The chemically modified ACs, along with a commercial AC (S208c), were saturated with ortho- (OCP) and meta-chlorophenol (MCP) to investigate the potential for thermally regenerating the spent ACs. The thermal regeneration process was monitored by thermal analysis (TGA/DSC), gas chromatography and mass spectrometry (GC/MS). Thermal desorption profiles showed that in most cases weight losses occur in two steps (weak physisorption at circa 220{sup o}C and strong chemisorption at circa 620{sup o}C). Intermediate steps at circa 400{sup o}C appeared in samples whose chemical treatments successfully weakened the interactions between strongly chemisorbed chlorophenol (CP) molecules and AC surfaces. The type and quantity of products of OCP and MCP desorption during the thermal regeneration of a spent AC depend on the chemical modification given to the AC prior to its use as CP adsorbent. Besides the original chlorophenols, thermal regeneration products can include chlorobenzene, dichloro-dibenzofuran, phenol, aliphatic and aromatic hydrocarbons, water, chlorides, carbon oxides, hydrogen, and char deposits. Mechanisms for the formation of these compounds are discussed. The char deposits built during this study did not appear to diminish the surface area or porosity of the chemically modified ACs following their thermal regeneration. (author)

  14. Silicon-doped carbon nanotubes: a potential resource for the detection of chlorophenols/chlorophenoxy radicals

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Haihui; Zhang Dongju; Wang Ruoxi [Institute of Theoretical Chemistry, Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan, 250100 (China)], E-mail: zhangdj@sdu.edu.cn

    2009-04-08

    Chlorinated phenols and chlorophenoxy radicals are known as predominant precursors for forming polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF), which are highly carcinogenic and persistent organic pollutants (POPs). Density functional theory (DFT) calculations have been carried out to explore the potential possibility of carbon nanotubes (CNTs) serving as the resource for detecting and/or adsorbing these PCDD/PCDF precursors. Based on the calculated results on a pristine (8, 0) CNT and a Si-doped (8, 0) CNT with and without the presence of a 2-chlorophenol (2-CP)/2-chlorophenoxy radical (2-CPR), the typical representative of chlorophenols/chlorophenoxy radicals, we propose that pristine carbon nanotubes (CNTs) may be unsuitable for the desired applications due to their poor capability for catching chlorinated phenols/chlorophenoxy radicals, on the other hand, Si-doped CNTs are expected to be a potential resource for detecting and/or adsorbing (concentrating) these PCDD/PCDF precursors. The present results provide a guide to the relevant experimentalists, who are exploring novel applications of CNT-based materials in nanoscience and nanotechnology, and/or searching for suitable resources for detecting chlorophenols/chlorophenoxy radicals.

  15. Silicon-doped carbon nanotubes: a potential resource for the detection of chlorophenols/chlorophenoxy radicals

    Science.gov (United States)

    Jiang, Haihui; Zhang, Dongju; Wang, Ruoxi

    2009-04-01

    Chlorinated phenols and chlorophenoxy radicals are known as predominant precursors for forming polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF), which are highly carcinogenic and persistent organic pollutants (POPs). Density functional theory (DFT) calculations have been carried out to explore the potential possibility of carbon nanotubes (CNTs) serving as the resource for detecting and/or adsorbing these PCDD/PCDF precursors. Based on the calculated results on a pristine (8, 0) CNT and a Si-doped (8, 0) CNT with and without the presence of a 2-chlorophenol (2-CP)/2-chlorophenoxy radical (2-CPR), the typical representative of chlorophenols/chlorophenoxy radicals, we propose that pristine carbon nanotubes (CNTs) may be unsuitable for the desired applications due to their poor capability for catching chlorinated phenols/chlorophenoxy radicals, on the other hand, Si-doped CNTs are expected to be a potential resource for detecting and/or adsorbing (concentrating) these PCDD/PCDF precursors. The present results provide a guide to the relevant experimentalists, who are exploring novel applications of CNT-based materials in nanoscience and nanotechnology, and/or searching for suitable resources for detecting chlorophenols/chlorophenoxy radicals.

  16. Degradation of 4-chlorophenol in aqueous solution by γ-radiation and ozone oxidation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The degradation of 4-chlorophenol (4-CP) by using gamma rays generated by a 60Co source in the presence of O3 was investigated. The radiolysis of 4-CP and the kinetics of 4-CP mineralization were analyzed based on the determination of total organic carbon (TOC). The influence of initial 4-CP concentration and the free radicals scavengers (such as NaHCO3 and t-butanol) on the 4-CP degradation was also studied. The results showed that when the radiation rate was 336 Gy·min(1, 4-chlorophenol at concentration of 10 mg·L(1 could be completely degraded at the radiation dose of 2 kGy. The degradation of 4-chlorophenol could be described by a first-order reaction model, the rate constant of 4-CP degradation by combined ozonation and radiation was 0.1016 min(1, which was 2.4 times higher than the sum of radiation (0.0294 min(1) and ozonation (0.0137 min(1). It revealed that the combination of radiation and ozonation resulted in synergistic effect, which can remarkably increase the degradation efficiency of 4-CP.

  17. Preferential adsorption of pentachlorophenol from chlorophenols-containing wastewater using N-doped ordered mesoporous carbon.

    Science.gov (United States)

    Yang, Bin; Liu, Yunpeng; Li, Zhongjian; Lei, Lecheng; Zhou, Jie; Zhang, Xingwang

    2016-01-01

    Preferential removal of pentachlorophenol (PCP) from chlorophenols-containing wastewater has been attracted more attentions in wastewater treatment, since it is one of the most toxic pollutants. The adsorbent of N-doped ordered mesoporous carbon (M-OMC) with high BET surface area of 1901 m(2)/g, large pore volume of 1.64 cm(3)/g and uniform pore size of 3.45 nm has been successfully synthesized via evaporation-induced self-assembly (EISA) method. The effects of solution pH, pore structure of adsorbent and their surface chemical properties on PCP adsorption by M-OMC were investigated in comparison with ordered mesoporous carbon (OMC), and much higher PCP adsorption capacities of M-OMC were obtained. The significantly preferential adsorption of PCP was achieved in the treatment of tri-component wastewater including PCP, p-chlorophenol (CP) and 2.4.6-trichlorophenol (TCP), and its adsorption process well fitted the pseudo-second-order kinetics model and the Langmuir isotherm. The initial sorption rate of PCP was 103.5 μmol/(g/min), which was 2.97 times of TCP. It may be attributed to the intensification of π-π interaction between PCP and M-OMC with the nitrogen functional groups. Therefore, M-OMC is promising for removal of PCP in the adsorption pretreatment of chlorophenols-containing wastewater.

  18. Synthesis of Pd nanoparticles decorated with graphene and their application in electrocatalytic degradation of 4-chlorophenol.

    Science.gov (United States)

    Bian, Zhao-Yong; Bian, Yu; Wang, Hui; Ding, Ai-Zhong

    2014-09-01

    Pd/graphene catalysts were prepared in situ from graphite oxide and palladium salts by the hydrogen-reduction method and were then used for the construction of Pd/graphene gas-diffusion electrodes (GDE). The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential pulse voltammetry (DPV) techniques. In the Pd/graphene catalysts, Pd particles, with an average size of 3.6 nm and an amorphous structure, were highly dispersed in the graphene. The Pd/graphene catalysts accelerated the two-electron reduction of O2 to H2O2 by feeding air, which favors the production of hydroxyl radicals (HO*). In the electrolytic system, HO* was determined in the reaction mixture by the electron spin resonance spectrum (ESR). The dechlorination degree of 4-chlorophenol reached approximately 90.5% after 80 min, and the removal efficiency and the average removal efficiency of 4-chlorophenol, in terms of total organic carbon (TOC) after 120 min, reached approximately 93.3% and 85.1%, respectively. Furthermore, based on the analysis of electrolysis intermediates by high performance liquid chromatography (HPLC) and ion chromatography (IC), a reaction scheme was proposed for the Pd/grapheme GDE catalytic degradation of 4-chlorophenol.

  19. Use of polyoxyethylene-6-lauryl ether and microwave-assisted extraction for the determination of chlorophenols in marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Cristina Mahugo; Ferrera, Zoraida Sosa; Rodriguez, Jose J. Santana

    2004-10-25

    Microwave-assisted micellar extraction was optimised and applied to the extraction, prior to analysis by liquid chromatography with diode array spectrophotometric detection, of chlorophenols in marine sediment samples. This study was carried out using a non-ionic surfactant polyoxyethylene-6-lauryl ether as extractant. Parameters studied included surfactant concentration, pH of the solution, extraction time and power. Once the method was optimised, it was applied to different spiked marine sediments from coasts of the Canary Islands (Spain). The results obtained indicate that irradiation of 500 W for 2 min achieved the best extraction efficiency (100% recovery) and standard deviation values <10%. Detection limits were obtained in the range 1.2-12.7 {mu}g g{sup -1} for the chlorophenols studied. The proposed method provides a simple, fast and organic solvent-free procedure to analyse for chlorophenols in marine sediment samples.

  20. The influence of metal ions on the photocatalytic oxidation of 2-chlorophenol in aqueous titanium dioxide suspensions

    International Nuclear Information System (INIS)

    This study investigated the effect of metal ions,such as Fe3+, Cu2+, Ni2+, Cr3+ and Zn2+, on the photocatalytic oxidation of 2-chlorophenol with illumination of 254 nm and 365 nm UV lights. Different metal ions have individual reduction potentials, and hence, their abilities to capture electrons also differ; the rates of 2-chlorophenol decomposition vary as well. This study was made to explore the relationships between the reduction potentials of different metal ions and their photocatalytic rates of 2-chlorophenol. Results show that when the reduction potential is greater than zero, regardless of illumination wavelength, the reaction rate increases with increasing reduction potentials of the metal ions. When the reduction potential is less than zero, the reaction rates are about the same for illumination of 365 nm or 254 nm UV lights. (author)

  1. Evaluation of removal efficiency of 2-chlorophenol in aquatic environments by modified fly ash

    Directory of Open Access Journals (Sweden)

    Mohammad Malakootian

    2015-12-01

    Full Text Available Background: Chlorophenols are classified as priority toxic pollutants. These acidic organic compounds present a serious potential hazard for human health and aquatic life. Chlorophenols accumulate in water, soil and air due to high stability, and impart an unpleasant taste and odor to drinking water and can exert negative effects on different biological processes. Among the different methods of removal, adsorption process by low price adsorbents, such as fly ash (FA is common. Therefore, in this study, the effects of oxidation of FA as modified adsorbent were investigated when the adsorption of 2-chlorophenol (2-CP was increased. Methods: This experimental study was conducted from March to September of 2013. FA obtained from Zarand power plant (located in Kerman province was oxidized with potassium permanganate. Effective factors on the oxidation of FA, such as temperature, oxidation time and concentrations of oxidizers were optimized. Raw sewage of Zarand coal washing plant was tested under optimal conditions. All tests were carried out according to the standard methods book for the examination of water and wastewater. Results: Optimal condition for the preparation of oxidized FA was obtained at 70°C, 1 hour, and 1 mM of potassium permanganate concentration. The absorber obtained was able to remove 96.22% of 2-CP under optimized conditions (pH=3, 2 hours, adsorbent dose 0.8 g and room temperature. The removal efficiency of the real wastewater under optimal conditions was 82.1%. Conclusion: Oxidized FA can be used for the removal of this pollutant from industry wastewater due to its high efficiency of removal in real wastewater, it is easy and inexpensive to prepare and could modify the sorbent.

  2. Synthesis, characterization and application of an inorgano organic material: -chlorophenol anchored onto zirconium tungstate

    Indian Academy of Sciences (India)

    Beena Pandit; Uma Chudasama

    2001-06-01

    Tetravalent metal acid (TMA) salt zirconium tungstate (ZW) has been synthesized, followed by its derivatization using para-chlorophenol (CP). The resulting compound is abbreviated as ZWCP. ZWCP has been characterized for elemental analysis, spectral analysis (FTIR), X-ray analysis and thermal analysis (TGA). Its chemical stability has been assessed in various mineral acids, bases and organic solvents. Ion exchange capacity (IEC) has been determined and distribution behaviour towards several metal ions in different electrolyte solutions with varying concentrations has been studied and a few binary separations achieved.

  3. Uncovering the pKa dependent fluorescence quenching of carbon dots induced by chlorophenols

    Science.gov (United States)

    Zhang, Yu; Wang, Yu; Guan, Yafeng; Feng, Liang

    2015-03-01

    Fluorescence quenching induced by targets is always an alluring strategy to elucidate the possible photoluminescence origin of carbon dots. In this study, a new kind of N, S co-doped carbon dots (NSCDs) was synthesized and the fluorescence of NSCDs was surprisingly found to be quenched by chlorophenols (CPs) in a pKa dependent mode. Detailed investigation of this behavior demonstrated that phenolate was the responsible species and N and/or S dopants in NSCDs failed to play a role in the fluorescence quenching. Further evidence uncovered that the quenching was a static one, where a non-fluorescent intermediate was formed between electron-deficient C&z.dbd;O on the CDs surface and the electron-rich phenolic oxygen anion of chlorophenolate via nucleophilic addition. Moreover, one of the main photoluminescence origins of this kind of CDs was derived, namely surface emissive sites mostly attributed to carbonyl groups.Fluorescence quenching induced by targets is always an alluring strategy to elucidate the possible photoluminescence origin of carbon dots. In this study, a new kind of N, S co-doped carbon dots (NSCDs) was synthesized and the fluorescence of NSCDs was surprisingly found to be quenched by chlorophenols (CPs) in a pKa dependent mode. Detailed investigation of this behavior demonstrated that phenolate was the responsible species and N and/or S dopants in NSCDs failed to play a role in the fluorescence quenching. Further evidence uncovered that the quenching was a static one, where a non-fluorescent intermediate was formed between electron-deficient C&z.dbd;O on the CDs surface and the electron-rich phenolic oxygen anion of chlorophenolate via nucleophilic addition. Moreover, one of the main photoluminescence origins of this kind of CDs was derived, namely surface emissive sites mostly attributed to carbonyl groups. Electronic supplementary information (ESI) available: Texts, figures and tables giving partial experimental procedures, detailed characterizations

  4. Comparison of different chlorophenols degradation in aqueous solutions by gamma irradiation under reducing conditions

    Science.gov (United States)

    Peng, Yunxia; He, Shijun; Wang, Jianlong; Gong, Wenqi

    2012-10-01

    The reductive degradation of chlorophenols (CPs), including 2-CP, 4-CP and 2,4-DCP by gamma irradiation was investigated and compared. The results showed that the most efficient degradation took place with 2,4-DCP, followed by 2-CP and then 4-CP. This confirmed that the number and position of chlorine atoms existing in the benzene ring have significant impact on dechlorination and decomposition of CPs. The G-values of decomposition of CPs, the formation of intermediate products and chloride ion, and the degradation rate (KCPs and K) were also determined.

  5. PCDD/F formation from chlorophenols by lignin and manganese peroxidases

    OpenAIRE

    Muñoz Fernández, María; Gómez-Rico Núñez de Arenas, María Francisca; Font Montesinos, Rafael

    2014-01-01

    Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) formation was studied, in vitro, with two different chlorophenol mixtures (group “di+tri” 2,4-dichlorophenol; 2,3,4-, 2,3,5-, and 3,4,5-trichlorophenols and group “tri+tetra+penta” with 2,4,5-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol) and two different lignolytic enzymes, lignin and manganese peroxidase (LiP and MnP respectively), which can be found during the composting process of sewage sludg...

  6. Kinetics of cometabolic degradation of 2-chlorophenol and phenol by Pseudomonas putida

    Institute of Scientific and Technical Information of China (English)

    Xing-ping LIU

    2009-01-01

    In order to address the complex cometabolic degradation of toxic compounds,batch experiments on the biodegradation of 2-chlorophenol (2-CP) and phenol by Pseudomonas putida were carried out.The experimental results show that 2-CP has an inhibitory effect on cell growth and phenol degradation,which demonstrates that the interaction between substrates affects cell growth and substrate degradation.A kinetic model of cell growth and substrate transformation was also developed.The square of the correlation coefficient from the experiment was 0.97,indicating that this model properly simulates the cometabolic degradation of 2-CP and phenol.

  7. Fluorescent Sensing of Chlorophenols in Water Using an Azo Dye Modified β-Cyclodextrin Polymer

    OpenAIRE

    Bhekie B. Mamba; Phendukani Ncube; Krause, Rui W

    2011-01-01

    A water soluble azo dye modified β-cyclodextrin polymer 4 was synthesized and used as a chemosensor for the detection of chlorinated phenols, model chlorinated by-products (CBPs) of water treatment for drinking purposes. The characterization of the intermediates and the azo dye modified β-CD polymer was done by UV/Vis Spectrophotometry, FT-IR and 1H-NMR spectroscopies. The chlorophenols were capable of quenching the fluorescence of the polymer. The polymer showed greater sensitivity towards 2...

  8. Oxidative Degradation of o-Chlorophenol with Contact Glow Discharges in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    高锦章; 杨武; 刘永军; 陈平; 纳鹏君; 陆泉芳

    2003-01-01

    Contact glow discharge electrolysis (CGDE) of o-chlorophenol (2-CP) was investi-gated under different pH, voltages and initial concentrations. And the mechanism of the oxidationwas explored. The results suggested that the degradation followed the first order kinetic law;Fe2+ had a remarkable catalytic effect on the removal rate of o-chloropenol. In the presence ofFe2+, 2-CP underwent an exhaustive degradation, from which the major intermediates includedo-dihydroxybenze, p-hydroxybenze, p-benzoquione and carboxlic acids.

  9. Simple colorimetric assay for dehalogenation reactivity of nanoscale zero-valent iron using 4-chlorophenol

    DEFF Research Database (Denmark)

    Hwang, Yuhoon; Mines, Paul D.; Jakobsen, Mogens Havsteen;

    2015-01-01

    Despite the wide application of nanoscale zero valent iron (nZVI) for the treatment of a plethora of pollutants through reductive reactions, reactivity evaluation of nZVI towards dehalogenation has not been standardized. In this light, it was desired to develop a simple colorimetric assay...... react according to the indophenol reaction, as its para-position is blocked; the simple colorimetric assay for reducing reactivity determination of nZVI to organically bound halogens was developed, using 4-chlorophenol as the model substrate that is selectively reduced to phenol by nZVI. The sensitivity...

  10. COMPARISON OF DIFFERENT ADVANCED OXIDATION PROCESSES DEGRADING P-CHLOROPHENOL IN AQUEOUS SOLUTION

    OpenAIRE

    H. Movahedyan ، A. M. Seid Mohammadi ، A. Assadi

    2009-01-01

    In present study, degradation of p-chlorophenol using several oxidation systems involving advanced oxidation processes such as ultraviolet/H2O2, microwave/H2O2 and both in the absence of hydrogen peroxide in batch mode by photolytic pilot plant and modified domestic microwave oven was evaluated. The oxidation rate was influenced by many factors, such as the pH value, the amount of hydrogen peroxide, irradiation time and microwave power. The optimum conditions obtained for the best degradation...

  11. Chlorophenol hydroxylases encoded by plasmid pJP4 differentially contribute to chlorophenoxyacetic acid degradation.

    OpenAIRE

    Ledger, T.; Pieper, D. H.; González, B.

    2006-01-01

    Phenoxyalkanoic compounds are used worldwide as herbicides. Cupriavidus necator JMP134(pJP4) catabolizes 2,4-dichlorophenoxyacetate (2,4-D) and 4-chloro-2-methylphenoxyacetate (MCPA), using tfd functions carried on plasmid pJP4. TfdA cleaves the ether bonds of these herbicides to produce 2,4-dichlorophenol (2,4-DCP) and 4-chloro-2-methylphenol (MCP), respectively. These intermediates can be degraded by two chlorophenol hydroxylases encoded by the tfdB(I) and tfdB(II) genes to produce the resp...

  12. Temperature-induced phase changes in bismuth oxides and efficient photodegradation of phenol and p-chlorophenol.

    Science.gov (United States)

    Hu, Yin; Li, Danzhen; Sun, Fuqian; Weng, Yaqing; You, Shengyong; Shao, Yu

    2016-01-15

    A novel, simple and efficient approach for photodegrading phenol and p-chlorophenol, based on BixOy, was reported for the first time. Monoclinic Bi2O4 was prepared by the hydrothermal treatment of NaBiO3·2H2O. A series of interesting phase transitions happened and various bismuth oxides (Bi4O7, β-Bi2O3 and α-Bi2O3) were obtained by sintering Bi2O4 at different temperatures. The results demonstrated that the Bi2O4 and Bi4O7 phase had strong abilities towards the oxidative decomposition of phenol and p-chlorophenol and very high rates of TOC removal were observed. The characterization by XRD and XPS revealed that Bi(4+) in Bi2O4 and Bi(3.5+) in Bi4O7 were reduced to Bi(3+) during the reaction process. Singlet oxygen ((1)O2) was identified as the major reactive species generated by Bi2O4 and Bi4O7 for the photodegradation of p-chlorophenol and phenol. This novel approach could be used as a highly efficient and green technology for treating wastewaters contaminated by high concentrations of phenol and chlorophenols. PMID:26384997

  13. Effect Of Inorganic, Synthetic And Naturally Occurring Chelating Agents On Fe(II) Mediated Advanced Oxidation Of Chlorophenols

    Science.gov (United States)

    This study examines the feasibility and application of Advanced Oxidation Technologies (AOTs) for the treatment of chlorophenols that are included in US EPA priority pollutant list. A novel class of sulfate/hydroxyl radical-based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS, Fe(II)/H...

  14. Biological and photocatalytic treatment integrated with separation and reuse of titanium dioxide on the removal of chlorophenols in tap water

    Energy Technology Data Exchange (ETDEWEB)

    Suryaman, Dhanus, E-mail: dhanussuryaman@yahoo.com [Agency for the Assessment and Application of Technology, M.H. Thamrin No. 8, Jakarta 10340 (Indonesia); Department of Chemical and Biochemical Engineering, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Hasegawa, Kiyoshi [Department of Chemical and Biochemical Engineering, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)

    2010-11-15

    We investigated biological, photocatalytic, and combination of biological and photocatalytic treatments in order to remove a mixture of 2-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, and pentachlorophenol in tap water (total: 100 mg L{sup -1}, each: 25 mg L{sup -1}). The removal of chlorinated phenols was conducted with a flow biological treatment and a circulative flow photocatalytic treatment under black light and sunlight irradiations integrated with titanium dioxide separation and reuse. The combined biological-photocatalytic treatment significantly shortened the degradation and mineralization time of both the biological treatment and the photocatalytic treatment. The removed chlorophenols per hour by the combined biological-photocatalytic treatment was 25.8 mg h{sup -1}, whereas by the combined photocatalytic-biological treatment was 10.5 mg h{sup -1}. After a large portion of biodegradable 2-chlorophenol and 2,4-dichlorophenol, and around half amount of slightly biodegradable 2,4,5-trichlorophenol were removed by the biological treatment, the remained three chlorophenols, biorecalcitrant pentachlorophenol, and biodegradation products were completely removed by the subsequent photocatalytic treatment. Since titanium dioxide particles in tap water spontaneously sedimented on standing after the photocatalytic treatment, the combined treatment can be operated by integrating with the titanium dioxide separation and reuse. The TiO{sub 2} particles were recovered and reused at least three times without significantly decreasing the removal efficiency.

  15. CHLOROBENZENES, CHLOROPHENOLS, PHAS AND LOW CHLORINATED DIOXIN/FURAN POST-BOILER TOXICITY INDICATORS IN MUNICIPAL SOLID WASTE INCINERATORS

    Science.gov (United States)

    Research has sought indicator compounds for fast and less costly predictive monitoring of polychlorinated dibenzo-p-dioxin and furans, PCDD/F, toxic equivalent concentrations or TEQs. Studies have shown chlorobenzenes and chlorophenols had a good correlation with TEQ, suggesting ...

  16. Biological and photocatalytic treatment integrated with separation and reuse of titanium dioxide on the removal of chlorophenols in tap water

    International Nuclear Information System (INIS)

    We investigated biological, photocatalytic, and combination of biological and photocatalytic treatments in order to remove a mixture of 2-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, and pentachlorophenol in tap water (total: 100 mg L-1, each: 25 mg L-1). The removal of chlorinated phenols was conducted with a flow biological treatment and a circulative flow photocatalytic treatment under black light and sunlight irradiations integrated with titanium dioxide separation and reuse. The combined biological-photocatalytic treatment significantly shortened the degradation and mineralization time of both the biological treatment and the photocatalytic treatment. The removed chlorophenols per hour by the combined biological-photocatalytic treatment was 25.8 mg h-1, whereas by the combined photocatalytic-biological treatment was 10.5 mg h-1. After a large portion of biodegradable 2-chlorophenol and 2,4-dichlorophenol, and around half amount of slightly biodegradable 2,4,5-trichlorophenol were removed by the biological treatment, the remained three chlorophenols, biorecalcitrant pentachlorophenol, and biodegradation products were completely removed by the subsequent photocatalytic treatment. Since titanium dioxide particles in tap water spontaneously sedimented on standing after the photocatalytic treatment, the combined treatment can be operated by integrating with the titanium dioxide separation and reuse. The TiO2 particles were recovered and reused at least three times without significantly decreasing the removal efficiency.

  17. Removal of 3-chlorophenol from water using rice-straw-based carbon

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shanli [Department of Soil and Environmental Sciences and Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung 40227, Taiwan (China)]. E-mail: slwang@dragon.nchu.edu.tw; Tzou Yumin [Department of Soil and Environmental Sciences and Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung 40227, Taiwan (China); Lu Yihsien [Department of Soil and Environmental Sciences and Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung 40227, Taiwan (China); Sheng Guangyao [Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2007-08-17

    The removal of 3-chlorophenol (CP) from water by carbon derived from burning of rice straw was evaluated in this study. Rice straw was burned at 300 deg. C in the air to obtain rice carbon (RC). Scanning electron micrographs showed a highly porous structure of RC. NMR and FTIR spectroscopy suggested an enhanced aromaticity of RC and the presence of oxygen-containing functional groups. Adsorption of CP by RC was characterized by L-shaped nonlinear isotherms, suggesting surface adsorption rather than partitioning. The adsorption occurred most strongly when CP existed as a neutral species. The adsorption decreased with increasing pH due to increased deprotonation of surface functional groups of RC and dissociation of CP. The adsorption capacity determined by data-fitting to the Langmuir model was 14.2, 12.9, 11.4 and 4.9 mg g{sup -1} at pH 4, 6, 8 and 10, respectively. These results suggest that rice-straw-based carbon may be effectively used as a low-cost substitute for activated carbon for removal of chlorophenols from water.

  18. Bioconcentration of atrazine and chlorophenols into roots and shoots of rice seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Su Yuhong [Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Chemistry Department, Xinjiang University, Urumqi 830046 (China); Zhu Yongguan [Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)]. E-mail: ygzhu@mail.rcees.ac.cn

    2006-01-15

    Accumulation of o-chlorophenol (CP), 2,4-dichlorophenol (DCP), and atrazine (ATR), as single and mixed contaminants, from hydroponic solutions into roots and shoots of rice seedlings was studied following 48-h exposure of the plant roots. As single contaminants at low levels, the observed bioconcentration factors (BCFs) of CP and DCP with roots approximated the equilibrium values according to the partition-limited model. The BCF of atrazine with roots was about half the partition limit for unknown reasons. The BCFs of CP and ATR with shoots also approximated the partition limits, while the BCF for more lipophilic DCP with shoots was about half the estimated limit, due to insufficient water transport into plants for DCP. As mixed contaminants at low levels, the BCFs with both roots and shoots were comparable with those for the single contaminants; at high levels, the BCFs generally decreased because of the enhanced mixed-contaminant phytotoxicity, as manifested by the greatly reduced plant transpiration rate. - Uptakes of o-chlorophenol, 2,4-dichlorophenol, and atrazine at various levels from nutrient solution by roots and shoots of rice seedlings were investigated using a partition-limited model.

  19. Formation of PCDD/Fs in Oxidation of 2-Chlorophenol on Neat Silica Surface.

    Science.gov (United States)

    Mosallanejad, Seyedehsara; Dlugogorski, Bogdan Z; Kennedy, Eric M; Stockenhuber, Michael; Lomnicki, Slawomir M; Assaf, Niveen W; Altarawneh, Mohammednoor

    2016-02-01

    This contribution studies partial oxidation of 2-chlorophenol on surfaces of neat silica at temperatures of 250, 350, and 400 °C; i.e., temperatures that frequently lead to catalytic formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from their precursors. We have identified 2,6-dichlorophenol (2,6-DCPh), 2,4-dichlorophenol (2,4-DCPh), and 2,4,6-trichlorophenol (2,4,6-TriCPh), but have detected no chlorinated benzenes (CBzs). The detected chlorinated and nonchlorinated DD/Fs comprise dibenzo-p-dioxin (DD), 1- and 2-monochlorodibenzo-p-dioxin (1-, 2-MCDD), 1,6-, 1,9-, 1,3-dichlorodibenzo-p-dioxin (1,6-, 1,9-, 1,3-DCDD), 4-monochlorodibenzofuran (4-MCDF), and 4,6-dichlorodibenzofuran (4,6-DCDF) at the reaction temperatures of 350 and 400 °C. However, at a lower reaction temperature, 250 °C, we have detected no PCDD/Fs. We have demonstrated that neat silica surfaces catalyze the generation of PCDD/Fs from chlorophenols at the upper range of the catalytic formation temperature of PCDD/F. The present finding proves the generation of PCDD/Fs on particles of fly ash, even in the absence of transition metals. PMID:26713881

  20. Capillary gas chromatography with atomic emission detection for determining chlorophenols in water and soil samples

    Energy Technology Data Exchange (ETDEWEB)

    Campillo, Natalia [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Aguinaga, Nerea [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Vinas, Pilar [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Lopez-Garcia, Ignacio [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Hernandez-Cordoba, Manuel [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain)]. E-mail: hcordoba@um.es

    2005-11-03

    A purge-and-trap preconcentration system coupled to a GC equipped with a microwave-induced atomic emission detector was used to determine 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) in water and soil samples. The analytes were previously leached from the solid matrices into a 5% (w/v) sodium carbonate solution using an ultrasonic probe. It was necessary to acetylate the compounds before purging them from the aqueous medium, which, at the same time, improved their chromatographic separation. After selecting the optimal experimental conditions, the performance of the system was evaluated. Each chromatographic run took 26 min, including the purge time. Detection limits for 5 ml water samples ranged from 23 to 150 ng l{sup -1}, which is lower than the limits reached using the methods proposed by the US Environmental Pollution Agency (EPA) for chlorophenols in water. For soil samples, detection limits were calculated for 7 g samples, the resulting values ranging between 80 and 540 pg g{sup -1} for 2,4,6-TCP and 2-CP, respectively. The accuracy of the method was checked by analysing a certified reference soil, as well as fortified water and soil samples.

  1. Mineralization of 2-chlorophenol by sequential electrochemical reductive dechlorination and biological processes.

    Science.gov (United States)

    Arellano-González, Miguel Ángel; González, Ignacio; Texier, Anne-Claire

    2016-08-15

    In this work, a novel approach was applied to obtain the mineralization of 2-chlorophenol (2-CP) in an electrochemical-biological combined system where an electrocatalytic dehydrogenation process (reductive dechlorination) was coupled to a biological denitrification process. Reductive dechlorination of 2-CP was conducted in an ECCOCEL-type reactor on a Pd-Ni/Ti electrode at a potential of -0.40V vs Ag/AgCl(s)/KCl(sat), achieving 100 percent transformation of 2-CP into phenol. The electrochemically pretreated effluent was fed to a rotating cylinder denitrifying bioreactor where the totality of phenol was mineralized by denitrification, obtaining CO2 and N2 as the end products. The total time required for 2-CP mineralization in the combined electrochemical-biological process was 7.5h. This value is close to those previously reported for electrochemical and advanced oxidation processes but in this case, an efficient process was obtained without accumulation of by-products or generation of excessive energy costs due to the selective electrochemical pretreatment. This study showed that the use of electrochemical reductive pretreatment combined with biological processes could be a promising technology for the removal of recalcitrant molecules, such as chlorophenols, from wastewaters by more efficient, rapid, and environmentally friendly processes. PMID:27131458

  2. 2-chlorophenol sorption from aqueous solution using granular activated carbon and polymeric adsorbents

    Science.gov (United States)

    Ghatbandhe, A. S.; Jahagirdar, H. G.; Yenkie, M. K. N.; Deosarkar, S. D.

    2013-08-01

    Adsorption equilibrium and kinetics of 2-chlorophenol (2-CP) one of the chlorophenols (CPs) onto bituminous coal based Filtrasorb-400 grade granular activated carbon and three different types of polymeric adsorbents were studied in aqueous solution in a batch system. Langmuir isotherm models were applied to experimental equilibrium data of 2-CP adsorption. Equilibrium data fitted very well to the Langmuir equilibrium models of 2-CP. Adsorbent monolayer capacity Q Langmuir constant b and adsorption rate constants k a were evaluated. 2-CP adsorption using GAC is very rapid in the first hour of contact where 70-80% of the adsorbate is removed by GAC followed by a slow approach to equilibrium. Whereas in case of polymeric adsorbents 60-65% of the adsorbate is removed in the first 30 min which is then followed by a slow approach to equilibrium. The order of adsorption of 2-CP on different adsorbents used in the study is found to be in following order: F-400 > XAD-1180 > XAD-4 > XAD-7HP.

  3. Influence of humic acids of different origins on oxidation of phenol and chlorophenols by permanganate

    Energy Technology Data Exchange (ETDEWEB)

    He Di, E-mail: hedy1997@hotmail.com [State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin (China); Guan Xiaohong, E-mail: hitgxh@126.com [State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin (China); Ma Jun, E-mail: majun@hit.edu.cn [State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin (China); Yang Xue, E-mail: yangxue1_ok@163.com [State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin (China); Cui Chongwei, E-mail: cuichongwei1991@126.com [State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin (China)

    2010-10-15

    The influences of humic acids (HAs) of different origins, including two commercial HAs, three soil HAs and one aquatic HA, on phenols oxidation by permanganate were studied. The apparent second-order rate constants of 2-chlorophenol (2-CP)/phenol oxidation by permanganate in the presence of HAs at pH 7 followed the order of commercial HA (Shanghai) > soil HAs > commercial HA (Fluka) > aquatic HA. Moreover, the commercial HA (Shanghai) could accelerate the oxidation of different chlorophenols (CP) significantly under neutral condition. The FTIR analysis demonstrated greater content of C=C moieties and less amount of carboxylate, aliphatic groups and polysaccharide-like substances in soil HAs than in aqueous HA, suggesting that the increase of aromaticity in HA was beneficial to the oxidation of phenols by permanganate. The apparent second-order rate constants of 2-CP/phenol oxidation by permanganate in the presence of HAs correlated well with specific visible absorption (SVA) at 665 nm of HAs. High positive correlation coefficients (R{sup 2} > 0.75) implied that {pi}-electrons of HA strongly influenced the reactivity of 2-CP/phenol towards permanganate oxidation, which agreed well with positive correlation between Fluorescence Regional Integration (FRI) and the apparent second-order rate constants. The {pi}-{pi} interaction between HAs and phenols, the steric hindrance effect and the dissociation of phenols may affect the oxidation of phenols by permanganate in the presence of HA at pH = 7.0.

  4. Effect of chlorine content of chlorophenols on their adsorption by mesoporous SBA-15

    Institute of Scientific and Technical Information of China (English)

    Qingdong Qin; Ke Liu; Dafang Fu; Haiying Gao

    2012-01-01

    Studies on the effect of the chlorine content of chlorophenols(CPs)on their adsorption from aqueous solution by mesoporous SBA-15are important in understanding the mechanisms of CP adsorption.In this study,three CPs with different degrees of chlorine content(i.e.,2-chlorophenol,2,6-dichlorophenol and 2,4,6-trichlorophenol)were investigated.The effects of parameters such as temperature and solution pH were studied.The results showed that CP adsorption by SBA-15 increased with increasing number of chlorine substituents and depended strongly on the temperature and solution pH.Thermodynamic parameters such as Gibbs free energy change(ΔG0),enthalpy change(ΔH0)and entropy change(ΔS0)were also calculated.By comparison of the adsorption coefficient of CPs with varying physical-chemical properties(size,hydrophobicity and electron density),we propose that hydrophobic interactions between CPs and the SBA-15 surface,as well as electron donor-acceptor(EDA)complexes between oxygen of the siloxane surface of SBA-15(e--donor)and the π-system of the CPs(e--acceptor),were dominant adsorption mechanisms.

  5. Mineralization of 2-chlorophenol by sequential electrochemical reductive dechlorination and biological processes.

    Science.gov (United States)

    Arellano-González, Miguel Ángel; González, Ignacio; Texier, Anne-Claire

    2016-08-15

    In this work, a novel approach was applied to obtain the mineralization of 2-chlorophenol (2-CP) in an electrochemical-biological combined system where an electrocatalytic dehydrogenation process (reductive dechlorination) was coupled to a biological denitrification process. Reductive dechlorination of 2-CP was conducted in an ECCOCEL-type reactor on a Pd-Ni/Ti electrode at a potential of -0.40V vs Ag/AgCl(s)/KCl(sat), achieving 100 percent transformation of 2-CP into phenol. The electrochemically pretreated effluent was fed to a rotating cylinder denitrifying bioreactor where the totality of phenol was mineralized by denitrification, obtaining CO2 and N2 as the end products. The total time required for 2-CP mineralization in the combined electrochemical-biological process was 7.5h. This value is close to those previously reported for electrochemical and advanced oxidation processes but in this case, an efficient process was obtained without accumulation of by-products or generation of excessive energy costs due to the selective electrochemical pretreatment. This study showed that the use of electrochemical reductive pretreatment combined with biological processes could be a promising technology for the removal of recalcitrant molecules, such as chlorophenols, from wastewaters by more efficient, rapid, and environmentally friendly processes.

  6. Absence of polychlorinated dibenzodioxins and dibenzofurans after lactoperoxidase-catalyzed transformation of chlorophenols

    Energy Technology Data Exchange (ETDEWEB)

    Oeberg, L.G.; Swanson, S.E.

    1987-06-01

    Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) have been detected in many species and environments their bioresistance and toxicity being of great concern. PCDDs and PCDFs, or the predioxins and -furans, are formed from chlorophenols (CPs) by burning and pyrolysis by arcing and by photolysis. PCDDs and PCDFs have also been found in emissions from automobiles, municipal waste incinerators, and nickel and copper smelting. Peroxidases (POs), a group of heme-proteins, are found in many organs and organisms. They are exceptional enzymes because of low substrate specificity and multiple reaction mechanisms. This enzyme-catalyzed free radical reaction resembles reactions in pyrolysis, arcing, and photolysis. Halogenated phenols are among the peroxidase substrates, and phenolic substrates have been found to yield dibenzodioxin- and dibenzofuran like products. The question then arose whether CP's in peroxidase-mediated reactions could yield chlorinated dibenzodioxins and dibenzofurans. Since no-one has yet reported a biological formation of PCDDs and PCDFs the authors have analyzed the rpdoct mixture from the lactoperoxidase-catalyzed oxidation of some chlorophenols.

  7. Kinetics and Mechanism of Dechlorination of o-Chlorophenol by Nanoscale Pd/Fe

    Institute of Scientific and Technical Information of China (English)

    WEI Jian-jun; XU Xin-hua; LIU Yong

    2004-01-01

    Nanoscale Pd/Fe bimetallic particles were synthesized with an efficient method to dechlorinate o-chlorophenol. The nanoscale Pd/Fe particles were determined by transmission electron microscopy and BET specific surface area analysis. Most of the particles are in the size range of 20-100 nm. The BET specific surface area of synthesized nanoscale Pd/Fe particles is 12.4 m2/g. In contrast, a commercially available fine iron powder(<100 mesh) has a specific surface area of 0.49 m2/g. Batch studies demonstrated that the nanoscale particles can effectively dechlorinate o-chlorophenol. The dechlorination reaction takes place on the surface of synthesized nanoscale Pd/Fe bimetallic particles in a pseudo-first order reaction. The surface-area-normalized rate coefficients(kSA) are comparable to those reported in the literature for chlorinated ethenes. The observed reaction rate constants(kobs) are dominated by the mass fraction of Pd and the mass concentration of the nanoscale Pd/Fe particles.

  8. Usefulness of a PARAFAC decomposition in the fiber selection procedure to determine chlorophenols by means SPME-GC-MS

    Energy Technology Data Exchange (ETDEWEB)

    Morales, Rocio; Ortiz, M.C. [University of Burgos, Department of Chemistry, Faculty of Sciences, Burgos (Spain); Sarabia, Luis A. [University of Burgos, Department of Mathematics and Computation, Faculty of Sciences, Burgos (Spain)

    2012-05-15

    In this work, a procedure based on solid-phase microextraction and gas chromatography coupled with mass spectrometry is proposed to determine chlorophenols in water without derivatization. The following chlorophenols are studied: 2,4-dichlorophenol; 2,4,6-trichlorophenol; 2,3,4,6-tetrachlorophenol and pentachlorophenol. Three kinds of SPME fibers, polyacrylate, polydimethylsiloxane, and polydimethylsiloxane/divinylbenzene are compared to identify the most suitable one for the extraction process on the basis of two criteria: (a) to select the equilibrium time studying the kinetics of the extraction, and (b) to obtain the best values of the figures of merit. In both cases, a three-way PARAllel FACtor analysis decomposition is used. For the first step, the three-way experimental data are arranged as follows: if I extraction times are considered, the tensor of data, X, of dimensions I x J x K is generated by concatenating the I matrices formed by the abundances of the J m/z ions recorded in K elution times around the retention time for each chlorophenol. The second-order property of PARAFAC (or PARAFAC2) assesses the unequivocal identification of each chlorophenol, as consequence, the loadings in the first mode estimated by the PARAFAC decomposition are the kinetic profile. For the second step, a calibration based on a PARAFAC decomposition is used for each fiber. The best figures of merit were obtained with PDMS/DVB fiber. The values of decision limit, CC{alpha}, achieved are between 0.29 and 0.67 {mu}g L{sup -1} for the four chlorophenols. The accuracy (trueness and precision) of the procedure was assessed. This procedure has been applied to river water samples. (orig.)

  9. Hard coal as a potential low-cost adsorbent for removal of 4-chlorophenol from water.

    Science.gov (United States)

    Kuśmierek, Krzysztof; Zarębska, Katarzyna; Świątkowski, Andrzej

    2016-01-01

    The potential use of raw hard coals as low-cost adsorbents for the removal of 4-chlorophenol (4-CP) from aqueous solutions was examined. The effect of experimental parameters such as the pH and salt presence was evaluated. The kinetic studies showed the equilibrium time was found to be 2 h for all of the adsorbents and that the adsorption process followed the pseudo-second order kinetic model. The adsorption isotherms of the 4-CP on the hard coals were fitted to the Langmuir, Freundlich, Langmuir-Freundlich, Sips and Redlich-Peterson equations. Based on the results obtained, hard coals appear to be a promising adsorbent for the removal of some hazardous water pollutants, like 4-CP and related compounds. PMID:27120657

  10. Oxidative Degradation of 4-chlorophenol in Aqueous Induced by Plasma with Submersed Glow Discharge Electrolysis

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The oxidative degradation of 4-chlorophenol (4-CP) in aqueous solution induced by plasma with submersed glow discharge has been investigated. The concentration of 4-CP and the reaction intermediates were determined by high performance liquid chromatography (HPLC).Various influencing factors such as the initial pH, the concentration of 4-CP and the catalytic action of Fe2+ were examined.The results indicate that 4-CP is eventually degraded into inorganic ion, dioxide carbon and water. The attack of hydroxyl radicals on the benzene rings of 4-CP in the initial stage of oxidative reactions is presumed to be a key step. They also suggest that the reaction is of a pseudo-first order kinetic reaction and the proposed method is an efficient way for the 4-CP degradation.

  11. Photoelectron and UV absorption spectroscopy for determination of electronic configurations of negative molecular ions: Chlorophenols

    Energy Technology Data Exchange (ETDEWEB)

    Tseplin, E.E. [Institute of Molecular and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, October Prospect 151, Ufa 450075 (Russian Federation)], E-mail: tzeplin@mail.ru; Tseplina, S.N.; Tuimedov, G.M.; Khvostenko, O.G. [Institute of Molecular and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, October Prospect 151, Ufa 450075 (Russian Federation)

    2009-04-15

    The photoelectron and UV absorption spectra of p-, m-, and o-chlorophenols in the gas phase have been obtained. On the basis of DFT B3LYP/6-311++G(d, p) calculations, the photoelectron bands have been assigned to occupied molecular orbitals. From the TDDFT B3LYP/6-311++G(d, p) calculation results, the UV absorption bands have been assigned to excited singlet states of the molecules under investigation. For each excited state a dominant transition was found. It has been shown that the energies of these singlet transitions correlate with the energy differences between the ground-state molecular orbitals participating in them. Using the UV spectra interpretation, the electronic states of molecular anions detected earlier for the same compounds by means of the resonant electron capture mass-spectrometry have been determined.

  12. Removal of chlorophenols from aqueous solutions by sorption onto walnut, pistachio and hazelnut shells

    Directory of Open Access Journals (Sweden)

    Kuśmierek Krzysztof

    2015-03-01

    Full Text Available The efficiency of walnut, pistachio and hazelnut shells to remove three monochlorophenols (2-CP, 3-CP and 4-CP from aqueous solutions has been investigated. To describe the kinetic data pseudo-first and pseudo-second order models were used. The kinetics data were fitted better into the pseudo-second order model with the coefficient of determination values greater than 0.99. The k2 values increased in the order 4-CP < 3-CP < 2-CP. Sorption was also analyzed as a function of solution concentration at equilibrium. The experimental data received were found to be well described by the Freundlich isotherm equation. Effectiveness of chlorophenols removal from water on the walnut, pistachio and hazelnut shells was comparable. Individual differences in sorption of monochlorophenols were also negligible.

  13. [Degradation of 4-chlorophenol in aqueous solution by high-voltage pulsed discharge-ozone technology].

    Science.gov (United States)

    Wen, Yuezhong; Jiang, Xuanzhen; Liu, Weiping

    2002-03-01

    The combination of high voltage pulse discharge and ozonation as an advanced oxidation technology was used to investigate the degradation of 4-chlorophenol (4-CP) in water. The factors that affect the rate of degradation were discussed. The 1.95 x 10(-3) mol/L solutions of 4-CP were almost completely (96%) degraded after the discharge treatment of 30 min. The degradation of 4-CP was investigated as a function of the ozone concentration, radical scavenger and electrode distance. The rate of 4-CP degradation increases with an increase in ozone concentration and a decrease in the electrode distance from 20 mm to 10 mm. The presence of radical scavenger decreased the rate of 4-CP degradation.

  14. Degradation of 4-Chlorophenol Solution by Synergetic Effect of Dual-frequency Ultrasound with Fenton Reagent

    Institute of Scientific and Technical Information of China (English)

    赵德明; 徐新华; 雷乐成; 汪大翚

    2005-01-01

    4-Chlorophenol (4-CP) solution was treated by dual-frequency ultrasound in conjunction with Fenton reagent, and obvious improvement in the 4-CP degradation rate was observed in this advanced oxidation process.Experimental results showed that ultrasonic intensity, saturating gas and pH value affected greatly the 4-CP removal rate. Among four different saturating gases (Ar, 02, air and N2), 4-CP degradation with Ar-saturated solution was the best. However, in the view of practical wastewater treatment, using oxygen as the saturating gas would be more economical. The addition of Fenton reagent followed the first-order kinetics and increased the 4-CP degradation rate.The 4-CP removal rate increased by around 126% within 15 rain treatment. The synergetic effect of dual-frequency ultrasound with Fenton reagent on 4-CP degradation was obviously observed.

  15. Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel,simple,rapid,sensitive and highly selective flow injection procedure for the spectrophotometrie determination of chlorine dioxide in the presence of other chlorine species,viz,free chlorine,chlorite,chlorate and hypoehlorite,is developed.The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct speetrophotometrie determination for chlorine dioxide owing to the serious interference of free and combined chlorine.The procedure gave a linear calibration graph over the range 0-0.71 mg/L of chlorine dioxide.With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.

  16. Sorption of 2-Chlorophenol from aqueous solutions by functionalized cross-linked polymers

    Directory of Open Access Journals (Sweden)

    Rodrigo Martins Fráguas

    2013-01-01

    Full Text Available This manuscript describes the synthesis of three polymers based on styrene (STY, divinylbenzene (DVB and two different vinyl monomers: methyl methacrylate (MMA and acrylonitrile (AN. The STY-DVB, STY-DVB-MMA and STY-DVB-AN polymers were synthesized employing the aqueous suspension technique. Reaction yields were 73%, 81% and 75%, respectively. They were morphological and chemically characterized using different techniques. The extraction capacity of the polymers was evaluated using 2-chlorophenol. The polymer extraction capacities were evaluated varying contact time the (1 h, 3 h and 5 h, temperature (30 °C, 35 °C and 40 °C, and pH (3, 5.6 and 8. The STY-DVB-AN polymer was the most efficient; it removed around 95% of the analyte using a contact time 50 h.

  17. Hydrodechlorination of 4-chlorophenol in water with formic acid using a Pd/activated carbon catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, L.; Gilarranz, M.A.; Casas, J.A.; Mohedano, A.F. [Seccion de Ingenieria Quimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Rodriguez, J.J. [Seccion de Ingenieria Quimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)], E-mail: juanjo.rodriguez@uam.es

    2009-01-30

    This work reports on the feasibility of hydrodechlorination as a treatment technique for chlorophenols-bearing wastewaters using formic acid as a hydrogen source. 4-Chlorophenol (4-CPhOH) has been used as target compound and the experiments were carried out in batch and continuous mode with a commercial activated carbon-supported Pd (0.5 wt.%) catalyst. The variables studied in the batch runs were HCOOH/4-CPhOH molar ratio (10-1000), temperature (25-75 deg. C) and catalyst concentration (250-1000 mg/L). The continuous experiments were performed in a fixed bed reactor where aqueous solutions of formic acid and 4-CPhOH with molar ratios between 50 and 100 were continuously fed to the reactor, at different space-time values in the range of 10.7-42.8 kg{sub cat} h/mol. Reaction temperatures from 35 to 100 deg. C were tested and the pressure was fixed at 2.5 bar. Conversion values above 99% for 4-CPhOH were obtained in batch experiments, but using a HCOOH/4-CPhOH molar ratio as high as 500. Moreover, most of the phenol produced was adsorbed on the catalyst. Continuous runs were performed to evaluate the efficiency of the catalyst under lower HCOOH/4-CPhOH ratios and to explore the possibility of converting phenol to more hydrogenated products. The results indicated that the HCOOH/4-CPhOH molar ratios needed were an order of magnitude lower than those required in batch runs to achieve conversions of 4-CPhOH close to 95%. Besides, phenol was not the only reaction product formed, since a more hydrogenated product such as cyclohexanone was detected in the effluent, which indicates additional hydrogenation of phenol in contrast to the behaviour observed in batch experiments. A loss of activity was observed in the continuous runs after 20-30 h on stream.

  18. Dye-sensitized phototransformation of chlorophenols and their subsequent chemiluminescence reactions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Junli [School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Road, Wuxi 214122 (China); Song Qijun [School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Road, Wuxi 214122 (China)], E-mail: qsong@jiangnan.edu.cn; Hu Xia; Zhang Enhui; Gao Hui [School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Road, Wuxi 214122 (China)

    2008-12-15

    A novel chemiluminescence (CL) reaction of chlorophenols (CPs), including 2-chlorophenol (2-CP), 4-CP, 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP) was reported, which was based on the oxidation of the phototransformed CPs by N-bromosuccinimide (NBS). It was found that the dye-sensitized phototransformation is a prerequisite for the subsequent CL reaction, and the presence of 1.9x10{sup -2} mol L{sup -1} Triton X-100 or 3.7x10{sup -3} mol L{sup -1} CTAB can greatly enhance the CL intensity. A neutral sample solution with the presence of 2x10{sup -5} mol L{sup -1} fluorescein (FL) was found to be optimum for the phototransformation of 2-CP, 4-CP, 2,4-DCP and PCP, but a lower pH of 5.3 was more suitable for 2,4,6-TCP. Based on the CL reaction, detection limits of 8.6x10{sup -8}, 1.1x10{sup -7}, 1.5x10{sup -7}, 4.6x10{sup -8} and 3.0x10{sup -5} mol L{sup -1} were achieved, respectively, for 2-CP, 4-CP, 2,4-DCP, 2,4,6-TCP and PCP with the optimized conditions in the flow system. The mechanism of the phototransformation and the subsequent CL reaction were preliminarily studied and it was suggested that the singlet oxygen formed in the dye-sensitization process was responsible for the conversion of CPs into light-emitting precursors. These intermediate products were suggested to be peroxide compounds after testing by a luminal-based post-column CL detection experiment.

  19. Catalytic wet air oxidation of 2-chlorophenol over sewage sludge-derived carbon-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Yuting [Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), CNRS – Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Xiong, Ya; Tian, Shuanghong [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275 (China); Kong, Lingjun [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Descorme, Claude, E-mail: claude.descorme@ircelyon.univ-lyon1.fr [Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), CNRS – Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2014-07-15

    Highlights: • A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared. • FeSC exhibited high catalytic activity in the wet air oxidation of 2-chlorophenol. • A strong correlation was observed between the 2-CP conversion, the iron leaching and the pH. • Using an acetate buffer, the iron leaching was suppressed while keeping some catalytic activity. • A simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst. - Abstract: A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared and used in the Catalytic Wet Air Oxidation (CWAO) of 2-chlorophenol (2-CP). The catalysts were characterized in terms of elemental composition, surface area, pH{sub PZC}, XRD and SEM. The performances of the FeSC catalyst in the CWAO of 2-CP was assessed in a batch reactor operated at 120 °C under 0.9 MPa oxygen partial pressure. Complete decomposition of 2-CP was achieved within 5 h and 90% Total Organic Carbon (TOC) was removed after 24 h of reaction. Quite a straight correlation was observed between the 2-CP conversion, the amount of iron leached in solution and the pH of the reaction mixture at a given reaction time, indicating a strong predominance of the homogeneous catalysis contribution. The iron leaching could be efficiently prevented when the pH of the solution was maintained at values higher than 4.5, while the catalytic activity was only slightly reduced. Upon four successive batch CWAO experiments, using the same FeSC catalyst recovered by filtration after pH adjustment, only a very minor catalyst deactivation was observed. Finally, based on all the identified intermediates, a simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst.

  20. Bioremediation of 2-chlorophenol containing wastewater by aerobic granules-kinetics and toxicity

    International Nuclear Information System (INIS)

    Highlights: → 2-Chlorophenol degrading aerobic granules were cultivated in sequencing batch reactor in presence of glucose and the organic loading rate (OLR) was increased from 6.9 to 9.7 kg COD m-3 d-1 during the experiment. → Spectral studies confirmed that the biodegradation occurs via chlorocatechol pathway and modified ortho-cleavage. → Biodegradation kinetics of 2-CP followed the Haldane model with kinetic parameters (R2 > 0.9) Vmax = 840 mg2-CP gMLVSS-1 d-1, Ks = 24.61 mg L-1, Ki = 315.02 mg L-1. → Genotoxic examination by plasmid nicking assay confirmed that the effluent was non-toxic. - Abstract: 2-Chlorophenol (2-CP) degrading aerobic granules were cultivated in a sequencing batch reactor (SBR) in presence of glucose. The organic loading rate (OLR) was increased from 6.9 to 9.7 kg COD m-3 d-1 (1150-1617 mg L-1COD per cycle) during the experiment. The alkalinity (1000 mg L-1 as CaCO3) was maintained throughout the experiment. The specific cell growth rate was found to be 0.013 d-1. A COD removal efficiency of 94% was achieved after steady state at 8 h HRT (hydraulic retention time). FTIR, UV, GC, GC/MS studies confirmed that the biodegradation of 2-CP occurs via chlorocatechol (modified ortho-cleavage) pathway. Biodegradation kinetics followed the Haldane model with kinetic parameters: Vmax = 840 mg2-CP gMLVSS-1 d-1, Ks = 24.61 mg L-1, Ki = 315.02 mg L-1. Abiotic losses of 2-CP due to volatilization and photo degradation by sunlight were less than 3% and the results of genotoxicity showed that the degradation products are eco-friendly.

  1. [Toxicity of 4-Chlorophenol Solution Under Electrochemical Reduction-oxidation Process].

    Science.gov (United States)

    Wang, Yan; Shi, Qin; Wang, Hui; Bian, Zhao-yong

    2016-04-15

    The Pd-Fe/graphene multi-functional catalytic cathode was prepared by UV-assisted photocatalytic reduction. The catalytic cathode and a Ti/IrO₂/RuO₂ anode consisting of both three-electrode system (two cathodes) and two-electrode system (one cathode) were designed for the degradation of 4-chlorophenol in aid of olectrochemical reducing and oxidizing processes. The concentrations of the intermediates and products were monitored by high performance liquid chromatography (HPLC), total organic carbon (TOC), and ion chromatography (IC). The theoretical toxicity was calculated according to the formula. The actual toxicity of the solution during the degradation process was detected using the luminescent bacteria. The comparison of the actual toxicity and theoretical toxicity was performed to analyze the trend of the two systems. The results showed that the toxicity of the solution in anode compartment first increased and then decreased, but the toxicity in cathode compartment decreased during the whole degradation for both systems. This trend could be attributed to the intermediate formed, benzoquinone. Through the analysis of correlation, the correlation coefficient was 1 of the theoretical toxicity and actual toxicity at the level of P = 0.01, which indicated the result of toxicity was reliable. The toxicity of three-electrode system was lower than that of two-electrode system after 120 mm. The three-electrode system was considered to be better than the two-electrode system. Therefore, the detection of actual toxicity in electrochemical reducing and oxidizing process for the degradation of chlorophenols in the actual industry has wide application prospect. PMID:27548966

  2. Single and mixture toxicity of pharmaceuticals and chlorophenols to freshwater algae Chlorella vulgaris.

    Science.gov (United States)

    Geiger, Elisabeth; Hornek-Gausterer, Romana; Saçan, Melek Türker

    2016-07-01

    Organisms in the aquatic environment are exposed to a variety of substances of numerous chemical classes. The unintentional co-occurrence of pharmaceuticals and other contaminants of emerging concern may pose risk to non-target organisms. In this study, individual and binary mixture toxicity experiments of selected pharmaceuticals (ibuprofen and ciprofloxacin) and chlorophenols (2.4-dichlorophenol (2,4-DCP) and 3-chlorophenol (3-CP)) have been performed with freshwater algae Chlorella vulgaris. All experiments have been carried out according to the 96-h algal growth inhibition test OECD No. 201. Binary mixture tests were conducted using proportions of the respective IC50s in terms of toxic unit (TU). The mixture concentration-response curve was compared to predicted effects based on both the concentration addition (CA) and the independent action (IA) model. Additionally, the Combination Index (CI)-isobologram equation method was used to assess toxicological interactions of the binary mixtures. All substances individually tested had a significant effect on C. vulgaris population density and revealed IC50 values ciprofloxacin>3-CP>ibuprofen. Generally, it can be concluded from this study that toxic mixture effects of all tested chemicals to C. vulgaris are higher than the individual effect of each mixture component. It could be demonstrated that IC50 values of the tested mixtures predominately lead to additive effects. The CA model is appropriate to estimate mixture toxicity, while the IA model tends to underestimate the joint effect. The CI-isobologram equation method predicted the mixtures accurately and elicited synergism at low effect levels for the majority of tested combinations. PMID:27045919

  3. Rotating biological contractor treatment of 2-nitrophenol and 2-chlorophenol containing hazardous wastes

    International Nuclear Information System (INIS)

    Rotating Biological Contactors (RBCs) have a number of advantages over other biological treatment systems. For example, they can provide high treatment efficiencies of activated sludge systems with much lower energy inputs. Organic shock loads are handled well because large biomass is present. No bulking, foaming, or floating of sludge occurs and sludge has good settleability and dewaterability. Another advantage of RBC systems is the minimal labor requirement for operation and maintenance. Even though RBC systems have these advantages, their acceptance was slow mainly due to operational problems with the earlier units (such as shaft failures) and the lack of considerable design and operation data. A review of literature shows that there is only limited information available on the wastewater treatment with RBCs. Recently, there has been considerable contributions to the knowledge on RBC technology. However, information on the treatment of organic hazardous wastes using RBCs is still very limited. This paper reports that a considerable number of studies on the biological treatment of organic hazardous compounds was sponsored by U.S. Environmental Protection Agency (EPA). For example, an EPA sponsored study examined the effect of such compounds on the performance of activated sludge process. Bench-scale continuous-flow and batch units were used. Influent was settled municipal wastewater to which toxic compounds were added. In batch operations, 2-chlorophenol and pentachlorophenol caused an increase in the effluent Chemical Oxygen Demand (COD) at an influent concentration of 5 mg/L. No adverse effect of 2-nitrophenol on the batch system was reports. 2-Chlorophenol was one of the compounds that upset the performance of continuous-flow activated sludge units, yielding higher than normal levels of effluent suspended solids

  4. Electro-oxidation of chlorophenols at glassy carbon electrodes modified with polyNi(II)complexes

    International Nuclear Information System (INIS)

    The effect of the ligand macrocycle (phenylporphyrin (PP) or phthalocyanine (Pc)) and of the ligand substituent (-NH2 or -SO3-) on the catalytic activity for the electro-oxidation in a pH 11 buffer electrolyte of 2- and 4-chlorophenol (2-CP and 4-CP), 2,4- and 2,6-dichlorophenol (2,4-DCP and 2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) at glassy carbon electrodes modified with electropolymerized Ni(II) macrocycles was studied. The polyphenolic residue deposited at the electrode surface was characterized by cyclic voltammetry, impedance measurements, ex situ Fourier transform infrared spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). A band of aliphatic C=O stretching in the IR spectrum of the fouling film produced by potential cycling in 2,4,6-TCP indicated that the aromatic ring had been broken, yielding ketones, aldehydes and/or carboxylic acids. The sulphonated Ni(II) polymers, which showed the Ni(III)/Ni(II) process in the CV, had XP spectra typical of paramagnetic Ni(II), indicating that they contained Ni(OH)2 clusters. On the contrary, the CVs of the amino Ni(II) did not show the Ni(III)/Ni(II) process at all, this process appearing only after previous activation by potential cycling, and only to a small extent. As was to be expected, the XP spectra of activated amino films corresponded to diamagnetic Ni(II), showing that the concentration of Ni(OH)2 clusters was very small. The amino films were less active than the sulpho films for the oxidation of chlorophenols, in agreement with the lower concentration of Ni(OH)2 clusters in the former films. For all electrodes the highest activity was observed for 2,4,6-TCP, since its oxidation yields a phenolic residue which is much more porous than those produced by the other CPs.

  5. Electro-oxidation of chlorophenols on poly(3,4-ethylenedioxythiophene)-poly(styrene sulphonate) composite electrode

    Energy Technology Data Exchange (ETDEWEB)

    Pigani, L. [Dipartimento di Chimica, Universita di Modena e Reggio Emilia, via G. Campi, 18, 41100 Modena (Italy); Musiani, M. [Istituto per l' Energetica e le Interfasi, IENI-CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Pirvu, C. [Department of General Chemistry, University Politehnica of Bucharest, Calea Grivitei 132, 78126 Bucharest (Romania); Terzi, F. [Dipartimento di Chimica, Universita di Modena e Reggio Emilia, via G. Campi, 18, 41100 Modena (Italy); Zanardi, C. [Dipartimento di Chimica, Universita di Modena e Reggio Emilia, via G. Campi, 18, 41100 Modena (Italy); Seeber, R. [Dipartimento di Chimica, Universita di Modena e Reggio Emilia, via G. Campi, 18, 41100 Modena (Italy)]. E-mail: reseeber@unimore.it

    2007-01-01

    The electrochemical behaviour of chlorinated phenols on Pt/poly(3,4-ethylenedioxy)thiophene,LiClO{sub 4} and on Pt/poly(3,4-ethylenedioxy)thiophene,poly(sodium-4-styrenesulphonate) electrodes has been investigated in phosphate buffer solution. Poly(sodium-4-styrenesulphonate) exerts remarkable effect against the electrode fouling induced by oxidation of chlorophenols, allowing us to record the relevant anodic response even after repeated potential cycles. Hypotheses about the role exerted by poly(sodium 4-styrenesulphonate) are made, on the basis of evidences provided by several techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, electrochemical microgravimetry and atomic force microscopy. Thanks to the fact that different chlorophenols show differences in the voltammetric responses, depending on number and position of the chloro substituents on the aromatic ring, applications of the modified electrode in the analysis of mixtures of chlorinated phenols are possible.

  6. Interlaboratory validation of PrEN 12673: Water quality - Gas Chromatographic determination of some selected chlorophenols in water

    OpenAIRE

    Hoogerbrugge R; Ramlal MR; Stil GH; Gort SM; Heusinkveld HAG; Velde EG van der; van Zoonen P; LOC

    1997-01-01

    Een interlaboratorium vergelijkingsonderzoek is georganiseerd ten behoeve van de validatie van de voorlopige standaard methode PrEN 12673 Water quality - Gas Chromatographic determination of some selected chlorophenols in water. Deze vergelijking is uitgevoerd op drie typen water, namelijk drinkwater, oppervlaktewater en afvalwater. Voor ieder van de drie typen zijn weer drie monsters gemaakt, het originele water en het water waaraan telkens 10-12 chloorfenolen in respectievelijk een hoge en ...

  7. A new combined green method for 2-Chlorophenol removal using cross-linked Brassica rapa peroxidase in silicone oil.

    OpenAIRE

    Tandjaoui, Nassima; Abouseoud, Mahmoud; Couvert, Annabelle; Amrane, Abdeltif; Tassist, Amina

    2016-01-01

    International audience This study proposes a new technique to treat waste air containing 2-Chlorophenol (2-CP), namely an integrated process coupling absorption of the compound in an organic liquid phase and its enzymatic degradation. Silicone oil (47V20) was used as an organic absorbent to allow the volatile organic compound (VOC) transfer from the gas phase to the liquid phase followed by its degradation by means of Cross-linked Brassica rapa peroxidase (BRP) contained in the organic pha...

  8. Microrespirometric determination of the effectiveness factor and biodegradation kinetics of aerobic granules degrading 4-chlorophenol as the sole carbon source.

    Science.gov (United States)

    Vital-Jacome, Miguel; Buitrón, Germán; Moreno-Andrade, Ivan; Garcia-Rea, Victor; Thalasso, Frederic

    2016-08-01

    In this study, a microrespirometric method was used, i.e., pulse respirometry in microreactors, to characterize mass transfer and biodegradation kinetics in aerobic granules. The experimental model was an aerobic granular sludge in a sequencing batch reactor (SBR) degrading synthetic wastewater containing 4-chlorophenol as the sole carbon source. After 15 days of acclimation, the SBR process degraded 4-chlorophenol at a removal rate of up to 0.9kg CODm(-3)d(-1), and the degradation kinetics were well described by the Haldane model. The microrespirometric method consisted of injecting pulses of 4-chlorophenol into the 24 wells of a microreactor system containing the SBR samples. From the respirograms obtained, the following five kinetic parameters were successfully determined during reactor operation: (i) Maximum specific oxygen uptake rate, (ii) substrate affinity constant, (iii) substrate inhibition constant, (iv) maximum specific growth rate, and (v) cell growth yield. Microrespirometry tests using granules and disaggregated granules allowed for the determination of apparent and intrinsic parameters, which in turn enabled the determination of the effectiveness factor of the granular sludge. It was concluded that this new high-throughput method has the potential to elucidate the complex biological and physicochemical processes of aerobic granular biosystems. PMID:27054670

  9. Removal of chlorophenols in aqueous solution by carbon black low-cost adsorbents. Equilibrium study and influence of operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Vargas, Joaquin R.; Navarro-Rodriguez, Juan A.; Beltran de Heredia, Jesus [Department of Chemical Engineering and Physical Chemistry, Area of Chemical Engineering, Faculty of Sciences, University of Extremadura, Avda. de Elvas, s/n, E-06071 Badajoz (Spain); Cuerda-Correa, Eduardo M., E-mail: emcc@unex.es [Department of Organic and Inorganic Chemistry, Faculty of Sciences, University of Extremadura, Avda. de Elvas, s/n, E-06071 Badajoz (Spain)

    2009-09-30

    The adsorption process of chlorophenols (CPs) by low-cost adsorbents such as carbon blacks has been studied. The influence of different parameters such as temperature, pH, ionic strength and textural properties of the adsorbents on the adsorption process of pentachlorophenol has been analyzed. The adsorption process is exothermal and parameters such as pH and ionic strength exert a noticeable influence on the adsorption capacity of the solute. These parameters influence the adsorption capacity in an opposite manner. Thus an increase in pH seems to unfavor the adsorption process, whereas the adsorption capacity increases with increasing ionic strength. In order to analyze the influence of the number of chlorine atoms in the molecule of solute the adsorption process of different chlorophenols (i.e., 4-chlorophenol, 3,5-dichlorophenol, 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol) was analyzed. As the number of chlorine atoms (and thus the volume of the molecule) increases, the penetration of the solute through the porous texture of the adsorbent is difficult and, consequently, the adsorption capacity decreases.

  10. Formation of polychlorinated dibenzodioxins, benzenes and phenols from thermal degradation of 2-chlorophenol promoted by CuCl2

    Energy Technology Data Exchange (ETDEWEB)

    Visez, N.; Baillet, C.; Sawerysyn, J.P. [Lille-1 Univ. (France). Physicochimie des Processus de Combustion et de l' Atmosphere - UMR-CNRS

    2004-09-15

    processes of PCDD/Fs from chlorophenols as precursors. These investigations have shown that other organic byproducts, potentially toxic, could also be formed with PCDD/Fs. Born et al. have studied the formation of PCDD/Fs from isomers of monochlorophenol on model and real fly ashes using a fixed bed reactor. The reaction products observed were carbon monoxide, carbon dioxide, 2,4- dichlorophenol, 2,6-dichlorophenol, 2,4,6-trichlorophenol, PCDDs, monobenzofuran, polychlorodiphenylethers, polychlorobenzenes, methylene chloride and tetrachloroethylene. By investigating the PCDD/Fs formation from ortho-chlorinated phenols and copper chloride, Ryu and Mulholland have identified the following products: chlorophenols, chlorobenzenes, PCDD/Fs, tetrachloroethylene and benzoquinones Hell et al. have studied the reaction of 2,4,6-trichlorophenol on real and model fly ash using a fixed bed reactor. They have observed that polychlorobenzenes formation was favored when time and temperature were increased. This work is aimed at highlighting the organic compounds formed by thermal degradation of 2-chlorophenol (2CP) promoted by copper chloride using sealed tubes as closed reactors. It is clear that this experimental method is unrealistic when compared to conditions of industrial processes. However, it enables us to use residence times (from minutes to hours) long enough to get more informations on reactions pathways responsible for PCCD/Fs formation and degradation which would be difficult to obtain from experiments with much smaller residence times.

  11. Thermodynamic Study of Adsorption of Phenol, 4-Chlorophenol, and 4-Nitrophenol on Activated Carbon Obtained from Eucalyptus Seed

    Directory of Open Access Journals (Sweden)

    Nelson Giovanny Rincón-Silva

    2015-01-01

    Full Text Available Activated carbons from shell eucalyptus (Eucalyptus globulus were prepared by chemical activation through impregnation with solutions of two activators: sulfuric acid and sodium hydroxide, the surface areas for activated carbons with base were 780 and 670 m2 g−1 and the solids activated with acid were 150 and 80 m2 g−1. These were applying in adsorption of priority pollutants: phenol, 4-nitrophenol, and 4-chlorophenol from aqueous solution. Activated carbon with the highest adsorption capacity has values of 2.12, 2.57, and 3.89 on phenol, 4-nitrophenol, and 4-chlorophenol, respectively, and was activated with base. In general, all carbons adsorption capacity was given in the following order: 4-chlorophenol > 4-nitrophenol > phenol. Adsorption isotherms of phenols on activated carbons were fitted to the Langmuir, Freundlich, and Dubinin-Radusckevisch-Kanager models, finding great association between them and experimental data. A thermodynamic study was performed, the exothermic nature and spontaneous nature of the adsorption process were confirmed, and the favorability of adsorption on activated carbons with NaOH was confirmed by energy relations and concluded that the adsorption process of phenolic compounds from the activated carbon obtained is physical. The pH of solutions and pH at point of zero charge of the solid play an important role in the adsorption process.

  12. Modeling chlorophenols degradation in sequencing batch reactors with instantaneous feed-effect of 2,4-DCP presence on 4-CP degradation kinetics.

    Science.gov (United States)

    Sahinkaya, Erkan; Dilek, Filiz B

    2007-08-01

    Two instantaneously fed sequencing batch reactors (SBRs), one receiving 4-chlorophenol (4-CP) (SBR4) only and one receiving mixture of 4-CP and 2,4-dichlorophenol (2,4-DCP) (SBRM), were operated with increasing chlorophenols concentrations in the feed. Complete degradation of chlorophenols and high-Chemical oxygen demand (COD) removal efficiencies were observed throughout the reactors operation. Only a fraction of biomass (competent biomass) was thought to be responsible for the degradation of chlorophenols due to required unique metabolic pathways. Haldane model developed based on competent biomass concentration fitted reasonably well to the experimental data at different feed chlorophenols concentrations. The presence of 2,4-DCP competitively inhibited 4-CP degradation and its degradation began only after complete removal of 2,4-DCP. Based on the experimental results, the 4-CP degrader's fraction in SBRM was estimated to be higher than that in SBR4 since 2,4-DCP degraders were also capable of degrading 4-CP due to similarity in the degradation pathways of both compounds. PMID:17091347

  13. Modeling chlorophenols degradation in sequencing batch reactors with instantaneous feed-effect of 2,4-DCP presence on 4-CP degradation kinetics.

    Science.gov (United States)

    Sahinkaya, Erkan; Dilek, Filiz B

    2007-08-01

    Two instantaneously fed sequencing batch reactors (SBRs), one receiving 4-chlorophenol (4-CP) (SBR4) only and one receiving mixture of 4-CP and 2,4-dichlorophenol (2,4-DCP) (SBRM), were operated with increasing chlorophenols concentrations in the feed. Complete degradation of chlorophenols and high-Chemical oxygen demand (COD) removal efficiencies were observed throughout the reactors operation. Only a fraction of biomass (competent biomass) was thought to be responsible for the degradation of chlorophenols due to required unique metabolic pathways. Haldane model developed based on competent biomass concentration fitted reasonably well to the experimental data at different feed chlorophenols concentrations. The presence of 2,4-DCP competitively inhibited 4-CP degradation and its degradation began only after complete removal of 2,4-DCP. Based on the experimental results, the 4-CP degrader's fraction in SBRM was estimated to be higher than that in SBR4 since 2,4-DCP degraders were also capable of degrading 4-CP due to similarity in the degradation pathways of both compounds.

  14. Electro-oxidation of chlorophenols at glassy carbon electrodes modified with polyNi(II)complexes

    Energy Technology Data Exchange (ETDEWEB)

    Berrios, Cristhian [Facultad de Quimica y Biologia, Departamento de Ciencias del Ambiente, Universidad de Santiago de Chile (USACh), casilla 40, correo 33, Santiago (Chile); Marco, Jose F.; Gutierrez, Claudio [Instituto de Quimica Fisica ' Rocasolano' , CSIC, C. Serrano, 119, 28006, Madrid (Spain); Ureta-Zanartu, Maria Soledad [Facultad de Quimica y Biologia, Departamento de Ciencias del Ambiente, Universidad de Santiago de Chile (USACh), casilla 40, correo 33, Santiago (Chile)], E-mail: soledad.ureta@usach.cl

    2009-11-01

    The effect of the ligand macrocycle (phenylporphyrin (PP) or phthalocyanine (Pc)) and of the ligand substituent (-NH{sub 2} or -SO{sub 3}{sup -}) on the catalytic activity for the electro-oxidation in a pH 11 buffer electrolyte of 2- and 4-chlorophenol (2-CP and 4-CP), 2,4- and 2,6-dichlorophenol (2,4-DCP and 2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) at glassy carbon electrodes modified with electropolymerized Ni(II) macrocycles was studied. The polyphenolic residue deposited at the electrode surface was characterized by cyclic voltammetry, impedance measurements, ex situ Fourier transform infrared spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). A band of aliphatic C=O stretching in the IR spectrum of the fouling film produced by potential cycling in 2,4,6-TCP indicated that the aromatic ring had been broken, yielding ketones, aldehydes and/or carboxylic acids. The sulphonated Ni(II) polymers, which showed the Ni(III)/Ni(II) process in the CV, had XP spectra typical of paramagnetic Ni(II), indicating that they contained Ni(OH){sub 2} clusters. On the contrary, the CVs of the amino Ni(II) did not show the Ni(III)/Ni(II) process at all, this process appearing only after previous activation by potential cycling, and only to a small extent. As was to be expected, the XP spectra of activated amino films corresponded to diamagnetic Ni(II), showing that the concentration of Ni(OH){sub 2} clusters was very small. The amino films were less active than the sulpho films for the oxidation of chlorophenols, in agreement with the lower concentration of Ni(OH){sub 2} clusters in the former films. For all electrodes the highest activity was observed for 2,4,6-TCP, since its oxidation yields a phenolic residue which is much more porous than those produced by the other CPs.

  15. Bioremediation of 2-chlorophenol containing wastewater by aerobic granules-kinetics and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Mohammad Zain [Environmental Research Laboratory, Department of chemistry, Aligarh Muslim University, Faculty of Science, Aligarh 202002, UP (India); Mondal, Pijush Kanti, E-mail: pijushamu@gmail.com [Environmental Research laboratory, Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh 202002, UP (India); Sabir, Suhail, E-mail: sabirsuhail09@gmail.com [Environmental Research Laboratory, Department of chemistry, Aligarh Muslim University, Faculty of Science, Aligarh 202002, UP (India)

    2011-06-15

    Highlights: {yields} 2-Chlorophenol degrading aerobic granules were cultivated in sequencing batch reactor in presence of glucose and the organic loading rate (OLR) was increased from 6.9 to 9.7 kg COD m{sup -3} d{sup -1} during the experiment. {yields} Spectral studies confirmed that the biodegradation occurs via chlorocatechol pathway and modified ortho-cleavage. {yields} Biodegradation kinetics of 2-CP followed the Haldane model with kinetic parameters (R{sup 2} > 0.9) V{sub max} = 840 mg2-CP gMLVSS{sup -1} d{sup -1}, K{sub s} = 24.61 mg L{sup -1}, K{sub i} = 315.02 mg L{sup -1}. {yields} Genotoxic examination by plasmid nicking assay confirmed that the effluent was non-toxic. - Abstract: 2-Chlorophenol (2-CP) degrading aerobic granules were cultivated in a sequencing batch reactor (SBR) in presence of glucose. The organic loading rate (OLR) was increased from 6.9 to 9.7 kg COD m{sup -3} d{sup -1} (1150-1617 mg L{sup -1}COD per cycle) during the experiment. The alkalinity (1000 mg L{sup -1} as CaCO{sub 3}) was maintained throughout the experiment. The specific cell growth rate was found to be 0.013 d{sup -1}. A COD removal efficiency of 94% was achieved after steady state at 8 h HRT (hydraulic retention time). FTIR, UV, GC, GC/MS studies confirmed that the biodegradation of 2-CP occurs via chlorocatechol (modified ortho-cleavage) pathway. Biodegradation kinetics followed the Haldane model with kinetic parameters: V{sub max} = 840 mg2-CP gMLVSS{sup -1} d{sup -1}, K{sub s} = 24.61 mg L{sup -1}, K{sub i} = 315.02 mg L{sup -1}. Abiotic losses of 2-CP due to volatilization and photo degradation by sunlight were less than 3% and the results of genotoxicity showed that the degradation products are eco-friendly.

  16. Catalytic Wet Air Oxidation of o-Chlorophenol in Wastewater%邻氯苯酚废水的催化湿式氧化处理

    Institute of Scientific and Technical Information of China (English)

    徐新华; 汪大翚

    2003-01-01

    Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatmentof o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence ofcatalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removedby wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperatureof 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited highcatalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCrwas removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had bettercatalytic activity for the degradation of o-chlorophenol in wastewater.

  17. Photocatalytic oxidation of 4-chlorophenol using thermosensitive zinc phthalocyanine copolymer under visible light irradiation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel thermosensitive photocatalyst,P(NIPA-co-ZnMPc),has been prepared using zinc tetra(N-carbonylacrylic)aminophthalocya-nine(ZnMPc) to copolymerize with N-isopropylacrylamide(NIPA).The lower critical solution temperature(LCST) of P(NIPA-co-ZnMPc) measured by differential scanning calorimetry(DSC) was 33.5 °C.P(NIPA-co-ZnMPc) effectively catalyzes the oxidation of 4-chlorophenols(4-CP) using oxygen as oxidant under the visible light irradiation,and it has higher photocatalytic activity than ZnMPc under the same condition.The UV-vis spectra of them in aqueous solution indicate that the macromolecular chains in P(NIPA-co-ZnMPc) restrain the aggregation of ZnMPc availably,resulting in the enhanced photocatalytic performance.The results of photocatalytic oxidation at different temperatures show that P(NIPA-co-ZnMPc) presents the highest photocatalytic efficiency around the LCST,suggesting that the macromolecular structure of P(NIPA-co-ZnMPc) can directly influence their photocatalytic activity.The hydrodynamic radius of this copolymer at different temperatures implies the intermolecular hydrophobic aggregation around the LCST,which is advantageous for the enrichment and the photocatalytic oxidation of 4-CP.Due to the high stability of P(NIPA-co-ZnMPc),it can be cyclically used in homogeneous photocatalytic oxidation and heterogeneous separation.

  18. Photoelectrochemical sensing of 4-chlorophenol based on Au/BiOCl nanocomposites.

    Science.gov (United States)

    Yan, Pengcheng; Xu, Li; Xia, Jiexiang; Huang, Yan; Qiu, Jingxia; Xu, Qian; Zhang, Qi; Li, Huaming

    2016-08-15

    The Au/BiOCl composites have been prepared by a facile one-pot ethylene glycol (EG) assisted solvothermal reaction in the presence of ionic liquid 1-hexadecyl-3-methylimidazolium chloride ([C16mim]Cl). During the synthesis procedure, the [C16mim]Cl has been used as Cl source, solvent of this system, and dispersing agent to effectively disperse Au on the surface of BiOCl. The as-prepared samples have been systematically characterized by multiple instruments to investigate the structure, morphology, and photoelectrochemical properties. According to the photoelectrochemical data, the Au/BiOCl composites exhibit better photoelectrochemical performance toward the detection of 4-chlorophenol than that of the pure BiOCl. The photocurrent response of Au/BiOCl modified electrode is high and stable under light irradiation. The proposed Au/BiOCl modified electrode shows a wide linear response ranging from 0.16 to 20mgL(-1) with detection limit of 0.05mgL(-1). It indicates a dramatically promising application of bismuth oxyhalides in photoelectrochemical detection. It will be expected that the present study may be lightly extended to the monitor of other organic pollutants by photoelectrochemical detection of the Au/BiOCl composites. PMID:27260461

  19. Catalytic reductive dechlorination of p-chlorophenol in water using Ni/Fe nanoscale particles

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-hua; QUAN Xie; ZHANG Zhuo-yong

    2007-01-01

    Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH4)with reduction of Ni2+and Fe2+ in aqueous solution.The obtained Ni/Fe particles were characterized by TEM(transmission electron microscope),XRD(X-ray diffractometer),and N2-BET The dechlorination activity of the Ni/Fe was investigated using P-chlorophenol (p-CP)as a pmbe agent.Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate P-CP at relatively low metal to solution ratio of 0.4 g/L (Ni 5 wt%).The target with initial concentration of P-CP O.625 mmol/L was dechlorinted completely in 60 min under ambient temperature and pressure.Factors affecting dechlorination efficiency,including reaction temperature,pH,Ni loading percentage over Fe,and metal to solution ratio.were investigated.The possible mechanism of dechlorination of P-CP was proposed and discussed.The pseudo-first-order reaction took place on the surface of the Ni/Fe bimetallic particles,and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.

  20. Mineralization of 4-Chlorophenol under Visible Light Irradiation in the Presence of Aluminum and Zinc Phthalocyaninesulfonates

    Institute of Scientific and Technical Information of China (English)

    许宜铭; 胡美琴; 陈祖栩; 曾冬云

    2003-01-01

    Photosensitized oxidation of 4-chlorophenol (4CP) by the title complexes (AIPcS and ZnPcS) in aerated aqueous solution uponvisible light irradiation(λ=450nm) has been investigated using methanol as a disassociating reagent.It is confirmed that the monomeric species of the sesitizer is more active than the corresponding dimer in singlet oxygen generation for 4CP oxidation.However,the monomer is also the main component found in the sensitlzer's photobleaching, In this reload, AIPcS is much more stable than ZnPcS, and the Dhotoble~hlno is observed to proceed via singlet and triplet oxygen, respectlvely.The final products of 4CP oxidation in alkaline solution are carbon dioxide and chloride ions.while at pH=7 and pH=3 the p-benzoquinone is the product.The temperature is found to have influence on both the photosensitized degradation of methyl orange and ZnPcS photobleaching,with an activation energy of 15.8 and 24.2kJ/mol,respectively.

  1. Quantum Chemical and Kinetic Study on Polychlorinated Naphthalene Formation from 3-Chlorophenol Precursor.

    Science.gov (United States)

    Xu, Fei; Shi, Xiangli; Zhang, Qingzhu

    2015-01-01

    Polychlorinated naphthalenes (PCNs) are the smallest chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) and are often called dioxin-like compounds. Chlorophenols (CPs) are important precursors of PCN formation. In this paper, mechanistic and kinetic studies on the homogeneous gas-phase formation mechanism of PCNs from 3-CP precursor were investigated theoretically by using the density functional theory (DFT) method and canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT). The reaction priority of different PCN formation pathways were disscussed. The rate constants of crucial elementary steps were deduced over a wide temperature range of 600-1200 K. The mechanisms were compared with the experimental observation and our previous works on the PCN formation from 2-CP and 4-CP. This study shows that pathways ended with Cl elimination are favored over those ended with H elimination from the 3-CP precursor. The formation potential of MCN is larger than that of DCN. The chlorine substitution pattern of monochlorophenols has a significant effect on isomer patterns and formation potential of PCN products. The results can be input into the environmental PCN controlling and prediction models as detailed parameters, which can be used to confirm the formation routes of PCNs, reduce PCN emission and establish PCN controlling strategies. PMID:26334273

  2. 2,4-Dichlorophenol hydroxylase for chlorophenol removal: Substrate specificity and catalytic activity.

    Science.gov (United States)

    Ren, Hejun; Li, Qingchao; Zhan, Yang; Fang, Xuexun; Yu, Dahai

    2016-01-01

    Chlorophenols (CPs) are common environmental pollutants. As such, different treatments have been assessed to facilitate their removal. In this study, 2,4-dichlorophenol (2,4-DCP) hydroxylase was used to systematically investigate the activity and removal ability of 19CP congeners at 25 and 0 °C. Results demonstrated that 2,4-DCP hydroxylase exhibited a broad substrate specificity to CPs. The activities of 2,4-DCP hydroxylase against specific CP congeners, including 3-CP, 2,3,6-trichlorophenol, 2-CP, and 2,3-DCP, were higher than those against 2,4-DCP, which is the preferred substrate of previously reported 2,4-DCP hydroxylase. To verify whether cofactors are necessary to promote hydroxylase activity against CP congeners, we added FAD and found that the added FAD induced a 1.33-fold to 5.13-fold significant increase in hydroxylase activity against different CP congeners. The metabolic pathways of the CP degradation in the enzymatic hydroxylation step were preliminarily proposed on the basis of the analyses of the enzymatic activities against 19CP congeners. We found that the high activity and removal rate of 2,4-DCP hydroxylase against CPs at 0 °C enhance the low-temperature-adaptability of this enzyme to the CP congeners; as such, the proposed removal process may be applied to biochemical, bioremediation, and industrial processes, particularly in cold environments. PMID:26672451

  3. Quantum Chemical and Kinetic Study on Polychlorinated Naphthalene Formation from 3-Chlorophenol Precursor

    Directory of Open Access Journals (Sweden)

    Fei Xu

    2015-08-01

    Full Text Available Polychlorinated naphthalenes (PCNs are the smallest chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs and are often called dioxin-like compounds. Chlorophenols (CPs are important precursors of PCN formation. In this paper, mechanistic and kinetic studies on the homogeneous gas-phase formation mechanism of PCNs from 3-CP precursor were investigated theoretically by using the density functional theory (DFT method and canonical variational transition-state theory (CVT with small curvature tunneling contribution (SCT. The reaction priority of different PCN formation pathways were disscussed. The rate constants of crucial elementary steps were deduced over a wide temperature range of 600−1200 K. The mechanisms were compared with the experimental observation and our previous works on the PCN formation from 2-CP and 4-CP. This study shows that pathways ended with Cl elimination are favored over those ended with H elimination from the 3-CP precursor. The formation potential of MCN is larger than that of DCN. The chlorine substitution pattern of monochlorophenols has a significant effect on isomer patterns and formation potential of PCN products. The results can be input into the environmental PCN controlling and prediction models as detailed parameters, which can be used to confirm the formation routes of PCNs, reduce PCN emission and establish PCN controlling strategies.

  4. Catalytic activities of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol.

    Science.gov (United States)

    Oputu, Ogheneochuko; Chowdhury, Mahabubur; Nyamayaro, Kudzanai; Fatoki, Olalekan; Fester, Veruscha

    2015-09-01

    We report the catalytic properties of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol (4-CP). XRD, TEM, EDS, SAED, FTIR and BET were used to characterize the prepared material. Interaction between O3 and β-FeOOH was evident from the FTIR spectra. The removal efficiency of 4-CP was significantly enhanced in the presence of β-FeOOH compared to ozone alone. Removal efficiency of 99% and 67% was achieved after 40min in the presence of combined ozone and catalyst and ozone only, respectively. Increasing catalyst load increased COD removal efficiency. Maximum COD removal of 97% was achieved using a catalyst load of 0.1g/100mL of 4-CP solution. Initial 4-CP concentration was not found to be rate limiting below 2×10(-3)mol/L. The catalytic properties of the material during ozonation process were found to be pronounced at lower initial pH of 3.5. Two stage first order kinetics was applied to describe the kinetic behavior of the nanorods at low pH. The first stage of catalytic ozonation was attributed to the heterogeneous surface breakdown of O3 by β-FeOOH, while the second stage was attributed to homogeneous catalysis initiated by reductive dissolution of β-FeOOH at low pH. PMID:26354696

  5. Mechanism and kinetics of 2-chlorophenol decomposition using coupled ultrasound and electrocatalysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A coupled ultrasound/electrocatalysis(US/EC) process was used to enhance the decomposition effi-ciency of organics.The synergetic kinetics and the mechanism of 2-chlorophenol(2-CP) decomposi-tion with coupled US/EC were studied.It was found that in a US/EC process 2-CP is attacked by active radicals(such as hydroxyl radicals) to form 2-chloro-p-benzoquinone,and the latter is oxidized to simple organic acids when the ring is opened.The enhancement factor expressed by the apparent rate constant of 2-CP decomposition with coupled US/EC is 1.324 at a current density of 20 mA·cm-2,an ultrasonic frequency of 20 kHz,an ultrasonic intensity of 0.27 W·cm-2,and a 2-CP initial concentration of 200 mg·L-1,which means that a synergetic effect exists.A model derived from Langmuir adsorption theory of solid surface and reaction kinetics equations can describe exactly the decomposition of 2-CP with coupled US/EC.The numerical values are in good agreement with the experimental data.The model parameters are associated with reaction conditions.

  6. Assays on the simultaneous determination and elimination of chloroanisoles and chlorophenols from contaminated cork samples.

    Science.gov (United States)

    Insa, Sara; Salvadó, Victòria; Anticó, Enriqueta

    2006-07-28

    A method for the simultaneous determination of the chloroanisoles and chlorophenols in cork samples with gas chromatography has been evaluated in view to its application. All the stages of the suggested procedure have been submitted to an in-depth examination using spiked ground corks. The recoveries of the method, which involves a simultaneous extraction with n-pentane followed by a second extraction using an aqueous basic solution where the phenolic derivates are transferred and, subsequently, derivatised, have been satisfactory for the all analytes at the studied spiking concentration levels. Good precision data and limits of detection between 1 ng/g and 2 ng/g were obtained for almost all compounds. As real samples, naturally contaminated cork slabs taken from different sources have been analysed, showing the presence of 2,4,6-trichloroanisole (TCA) and, in lesser extent, its direct precursor, 2,4,6-trichlorophenol (TCP). Removal studies have been performed by washing these tainted cork slabs with different solutions: Milli-Q water, sodium hydroxide and commercial products. Sodium hydroxide solutions have led to better analyte elimination, and the complete removal of TCP from the cork has been accomplished together with 72% of TCA reduction has been achieved. PMID:16678838

  7. Adsorption of p-chlorophenol from aqueous solutions on bentonite and perlite.

    Science.gov (United States)

    Koumanova, Bogdana; Peeva-Antova, P

    2002-03-29

    The adsorption of p-chlorophenol (p-CP) from aqueous solutions on bentonite and perlite was studied. These materials are available in large quantities in Bulgaria. Model solutions of various concentrations (1-50 mgdm(-3)) were shaken with certain amounts of adsorbent to determine the adsorption capacity of p-CP on bentonite and perlite as well. The influence of several individual variables (initial adsorbate concentration, adsorbent mass) on the rate of uptake of the studied compound on the adsorbent was determined by carrying out experiments at different contact times using the batch adsorber vessel designed according to the standard tank configuration. Rapid adsorption was observed 20-30 min after the beginning for every experiment. After that, the concentration of p-CP in the liquid phase remained constant. The adsorption equilibrium of p-CP on bentonite and perlite was described by the Langmuir and the Freundlich models. A higher adsorption capacity was observed for bentonite (10.63 mgg(-1)) compared to that for perlite (5.84 mgg(-1)).

  8. Visible light photocatalytic degradation of 4-chlorophenol using C/ZnO/CdS nanocomposite

    Directory of Open Access Journals (Sweden)

    Atul B. Lavand

    2015-09-01

    Full Text Available C/ZnO/CdS nanocomposite was synthesized using the microemulsion method. Nanocomposite synthesized in the present work was characterized using X-ray diffractometer (XRD, scanning electron microscope (SEM, energy dispersive X-ray spectroscopy (EDX transmission electron microscope (TEM, diffuse reflectance and photoluminescence (PL spectroscopy. TEM study shows that CdS nanoparticles are successfully anchored on the surface of C doped ZnO nanorods. UV–visible spectrum of C/ZnO/CdS nanocomposite shows a red shift. CdS nanoparticles work as photo sensitizers to expand the photo-response of C doped ZnO to the visible region. Photoluminescence (PL spectroscopy reveals evidence for interaction between C/ZnO and CdS. PL quenching observed for C/ZnO/CdS nanocomposite is attributed to improved charge separation properties, which increases its photocatalytic efficiency. C/ZnO/CdS nanocomposite exhibits exceptionally high photocatalytic activity for degradation of 4-chlorophenol (CP via Z-scheme mechanism. C/ZnO/CdS nanocomposite is a highly stable and reusable photocatalyst.

  9. Mechanism and kinetics of 2-chlorophenol degradation in drinking water by photo-electrochemical synergic effect

    Institute of Scientific and Technical Information of China (English)

    SONG; Qiang; (宋; 强); QU; Jiuhui; (曲久辉)

    2003-01-01

    The synergic effect mechanism of photo-electrochemical oxidation is investigated in detail through reaction products and kinetics analysis in a photo-electric integral reactor with 2-chlorophenol (2-CP) as the model pollutant. A kinetics model is constructed for the combinatorial photo-electrochemical (CPE) degradation. A remarkable synergetic effect, which can significantly enhance the mineralization rate of the CPE process, is verified by the comparison of apparent kinetic constants. In the CPE process, complemental effects with multi-level and multi-pathway for pollutants degradation under our experimental conditions are speculated. It is proved that the degradation pathways are not only the simple summation of that of photolysis and electrolysis, but the formation of synergic effect through combination of several new acting approaches. The degradation efficiency is enhanced considerably by three factors, control of electrode poisoning by the UV irradiation, control of excitation and reaction trend of pollutants molecules by the UV irradiation, and control of activation effect and transfer trend by the oriented direct current (DC) electric field. An advanced oxidation system is set up through manifold of free radicals chain reactions in the CPE reactions, so that the aqueous organics can be mineralized fast and completely. It is proven by the kinetics analysis that the mineralization of organic pollutants is mainly attributed to the generation of very active hydroxyl radicals (OH@) in bulk solution from the CPE synergetic effect.

  10. Novel synergic combinatorial photoelectrochemical technology for degradation of trace of 2-chlorophenol in drinking water

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel combinatorial photoelectrochemical (CPE) technology with combination of ultraviolet (UV)- photolysis and direct current (DC) electrolysis is studied and discussed for drinking water purification. In the self-made compositive photo-electrolysis incorporate reactor, removal rate of the 2-chlorophenol as model environmental pollutants has been investigated experimentally in terms of applied voltage, pH value, flow velocity, temperature, and aeration conditions. A primary analysis of the combinatorial photoelectric synergic effect on the degradation of organic pollutants has been carried out. It is found that the best performance of CPE oxidation is achieved by the following conditions: DC voltage of 5.0 V combined with UV-254-raidation, near neutral of pH 8 with aeration of pure oxygen. The influences of circular velocity, temperature, and initial concentration of the pollutant are minor. Under the optimal conditions, removal ratio of 2-CP is higher than 50% in 30 min, and 100% removal ratio of 2-CP (5 × 10-6) can be reached and TOC removal ratio reached above 90% in 2.5 h. Complete mineralization is achieved eventually. It shows in our investigation that under the studied conditions the synergic effect of UV photolysis and DC electrolysis on the degradation of the model pollutant is remarkable and validated, which may be derived from the coexistence of mutual complementary mechanisms of photoelectrochemical action, and the radicals chain reactions resulted from photo activation and electrolysis excitation in the process of CPE oxidation.

  11. p-Chlorophenol adsorption on activated carbons with basic surface properties

    Science.gov (United States)

    Lorenc-Grabowska, Ewa; Gryglewicz, Grażyna; Machnikowski, Jacek

    2010-05-01

    The adsorption of p-chlorophenol (PCP) from aqueous solution on activated carbons (ACs) with basic surface properties has been studied. The ACs were prepared by two methods. The first method was based on the modification of a commercial CWZ AC by high temperature treatment in an atmosphere of ammonia, nitrogen and hydrogen. The second approach comprised the carbonization followed by activation of N-enriched polymers and coal tar pitch using CO 2 and steam as activation agent. The resultant ACs were characterized in terms of porous structure, elemental composition and surface chemistry (pH PZC, acid/base titration, XPS). The adsorption of PCP was carried out from an aqueous solution in static conditions. Equilibrium adsorption isotherm was of L2 type for polymer-based ACs, whereas L3-type isotherm was observed for CWZ ACs series. The Langmuir monolayer adsorption capacity was related to the porous structure and the amount of basic sites. A good correlation was found between the adsorption capacity and the volume of micropores with a width < 1.4 nm for polymer-based ACs. Higher nitrogen content, including that in basic form, did not correspond to the enhanced adsorption of PCP from aqueous solution. The competitive effect of water molecule adsorption on the PCP uptake is discussed.

  12. Quantum Chemical and Kinetic Study on Polychlorinated Naphthalene Formation from 3-Chlorophenol Precursor.

    Science.gov (United States)

    Xu, Fei; Shi, Xiangli; Zhang, Qingzhu

    2015-08-31

    Polychlorinated naphthalenes (PCNs) are the smallest chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) and are often called dioxin-like compounds. Chlorophenols (CPs) are important precursors of PCN formation. In this paper, mechanistic and kinetic studies on the homogeneous gas-phase formation mechanism of PCNs from 3-CP precursor were investigated theoretically by using the density functional theory (DFT) method and canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT). The reaction priority of different PCN formation pathways were disscussed. The rate constants of crucial elementary steps were deduced over a wide temperature range of 600-1200 K. The mechanisms were compared with the experimental observation and our previous works on the PCN formation from 2-CP and 4-CP. This study shows that pathways ended with Cl elimination are favored over those ended with H elimination from the 3-CP precursor. The formation potential of MCN is larger than that of DCN. The chlorine substitution pattern of monochlorophenols has a significant effect on isomer patterns and formation potential of PCN products. The results can be input into the environmental PCN controlling and prediction models as detailed parameters, which can be used to confirm the formation routes of PCNs, reduce PCN emission and establish PCN controlling strategies.

  13. Acetate-fed aerobic granular sludge for the degradation of 4-chlorophenol

    International Nuclear Information System (INIS)

    Chlorinated phenols are considered a critical environmental problem, due to their extreme toxicity and their widespread use both in industrial and agricultural activities. In this study, aerobic granular sludge was initially developed into an acetate-fed Granulated Sequencing Batch Reactor (GSBR) and then used for the degradation of low chlorinated 4-mono-chlorophenol (4CP), with readily biodegradable sodium acetate (NaAc) as co-substrate. Influent 4CP concentration ranged between 0 and 50 mg/l, with a maximum volumetric organic loading rate of 0.20 kg4CP/m3 d (0.32 kgCOD-4CP/m3 d). Differences in granules shape and size were observed with 4CP dosed in the influent at different concentrations, and the effects of such toxic compound on acetate removal were evaluated, with both unacclimated and acclimated biomass. Aerobic granules grown on acetate as carbon source proved to be an interesting solution for the degradation of 4CP, showing good resistance to high 4CP concentrations in the influent even if unacclimated (short term effects). Moreover, the monitoring of intermediate products and the evaluation of chloride release due to 4CP degradation proved that acclimated granular sludge could completely remove 4CP (long term effects), with high specific removal rates.

  14. Chemical degradation and toxicity reduction of 4-chlorophenol in different matrices by gamma-ray treatment

    Science.gov (United States)

    Kang, Sung-Wook; Shim, Seung-Bo; Park, Young-Kwon; Jung, Jinho

    2011-03-01

    Gamma-ray treatment of 4-chlorophenol (4-CP) in different matrices was studied in terms of both chemical degradation and toxicity reduction. Degradation of 4-CP in a complex effluent matrix was less efficient than that in ultrapure water. This is most likely due to the consumption of reactive radicals by matrix components, such as dissolved organic matter in effluents. The matrix effect caused much more profound changes in toxicity. Gamma-ray treatment of 4-CP in ultrapure water abruptly increased acute toxicity toward Daphnia magna while slightly decreased toxicity of 4-CP in effluent. In the presence of ZrO 2 catalyst, degradation of 4-CP as well as toxicity reduction was substantially improved mostly by adsorption of 4-CP onto the nanoparticles. It was found that benzoquinone, hydroquinone and 4-chlorocatechol were generated for ultrapure water sample while only 4-chlorocatechol was formed for effluent samples by gamma-ray treatment. As determined in this work, EC 50 values of benzoquinone (0.46 μM), hydroquinone (0.61 μM) and chlorocatechol (8.87 μM) were much lower than those of 4-CP (31.50 μM), explaining different toxicity changes of 4-CP in different matrices by gamma-ray treatment. The observed toxicity of gamma-ray treated 4-CP was well correlated with the one calculated from individual toxicity based on EC 50 value.

  15. Adsorptive Removal of Para-chlorophenol Using Stratified Tapered Activated Carbon Column

    Institute of Scientific and Technical Information of China (English)

    M.EE Sze; G. McKay

    2012-01-01

    The feasibility of adsorptive removal of single component organic compound (para-chlorophenol) by Calgon Filtrasorb 400 (F400) carbon was investigated. The Redlich-Peterson equation was found to be the best fit model for describing the equilibrium relationship between the para-chlorophenol adsorption onto F400 carbon. Four adsorption columns with different column geometry and adsorbent particle stratification were used to examine the adsorption kinetics onto F400 carbons. The Bed Depth Service Time (BDST) model was applied and modified to analyse the performance of the columns and the effect of different operating variables. When combining the effects of adsorption efficiency and the associated pressure drop of each type of adsorption columns tested, the carbon stratified tapered column has been determined to be the most efficient engineering option for removing organics, in which the enhancement of the adsorbent bed in terms of longer breakthrough time and higher saturation percentage is the greatest amongst the four types of columns with reasonably small pressure drop across the fixed-bed column.

  16. Parameter Identification of the 2-Chlorophenol Oxidation Model Using Improved Differential Search Algorithm

    Directory of Open Access Journals (Sweden)

    Guang-zhou Chen

    2015-01-01

    Full Text Available Parameter identification plays a crucial role for simulating and using model. This paper firstly carried out the sensitivity analysis of the 2-chlorophenol oxidation model in supercritical water using the Monte Carlo method. Then, to address the nonlinearity of the model, two improved differential search (DS algorithms were proposed to carry out the parameter identification of the model. One strategy is to adopt the Latin hypercube sampling method to replace the uniform distribution of initial population; the other is to combine DS with simplex method. The results of sensitivity analysis reveal the sensitivity and the degree of difficulty identified for every model parameter. Furthermore, the posteriori probability distribution of parameters and the collaborative relationship between any two parameters can be obtained. To verify the effectiveness of the improved algorithms, the optimization performance of improved DS in kinetic parameter estimation is studied and compared with that of the basic DS algorithm, differential evolution, artificial bee colony optimization, and quantum-behaved particle swarm optimization. And the experimental results demonstrate that the DS with the Latin hypercube sampling method does not present better performance, while the hybrid methods have the advantages of strong global search ability and local search ability and are more effective than the other algorithms.

  17. Determination of Phenol and Chlorophenols at Single-Wall Carbon Nanotubes/Poly(3,4-ethylenedioxythiophene) Modified Glassy Carbon Electrode Using Flow Injection Amperometry

    OpenAIRE

    Negussie Negash; Hailemichael Alemu; Merid Tessema

    2014-01-01

    Phenol and chlorophenols were investigated using single-wall carbon nanotubes (SWCNT) and poly(3,4-ethylenedioxythiophene) (PEDOT) composite modified glassy carbon electrode (SWCNT/PEDOT/GCE) as a detector in flow injection system. Optimization of experimental variables such as the detection potential, flow rate, and pH of the carrier solution (0.1 M sodium acetate) for the determination of phenol (P), 4-chlorophenol (CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachloro...

  18. Effects of a catalytic converter on PCDD/F, chlorophenol and PAH emissions in residential wood combustion.

    Science.gov (United States)

    Kaivosoja, T; Virén, A; Tissari, J; Ruuskanen, J; Tarhanen, J; Sippula, O; Jokiniemi, J

    2012-07-01

    Catalytic converters can be used to decrease carbon monoxide, organic compounds and soot from small-scale wood-fired appliances. The reduction is based on the oxidation of gaseous and particulate pollutants promoted by catalytic transition metal surfaces. However, many transition metals have also strong catalytic effect on PCDD/F formation. In this study birch logs were burned in a wood-fired stove (18 kW) with and without a catalytic converter with palladium and platinum as catalysts. PCDD/F, chlorophenol and PAH concentrations were analyzed from three phases of combustion (ignition, pyrolysis and burnout) and from the whole combustion cycle. PCDD/F emissions without the catalytic converter were at a level previously measured for wood combustion (0.15-0.74 ng N m(-3)). PAH emissions without the catalytic converter were high (47-85 mg N m(-3)) which is typical for batch combustion of wood logs. Total PAH concentrations were lower (on average 0.8-fold), and chlorophenol and PCDD/F levels were substantially higher (4.3-fold and 8.7-fold, respectively) when the catalytic converter was used. Increase in the chlorophenol and PCDD/F concentrations was most likely due to the catalytic effect of the platinum and palladium. Platinum and palladium may catalyze chlorination of PCDD/Fs via the Deacon reaction or an oxidation process. The influence of emissions from wood combustion to human health and the environment is a sum of effects caused by different compounds formed in the combustion. Therefore, the usage of platinum and palladium based catalytic converters to reduce emissions from residential wood combustion should be critically evaluated before wide-range utilization of the technology. PMID:22397840

  19. Deriving the aquatic predicted no-effect concentrations (PNECs) of three chlorophenols for the Taihu Lake, China.

    Science.gov (United States)

    Lei, Bing L; Huang, Sheng B; Jin, Xiao W; Wang, Zijian

    2010-12-01

    The Predicted No-Effect Concentration (PNEC) is a key for ecological risk assessment. In this paper, the aquatic species existing widely in the Taihu Lake were selected, and their toxicity data to 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP) were collected. The PNECs of 2,4-DCP; 2,4,6-TCP; and PCP were derived using three different approaches, i.e., the assessment factor (AF), species sensitivity distribution (SSD) as well as an eco-toxicological model (AQUATOX). As the results, PNEC(AF)s were 2.18 μg L(-1), 2.53 μg L(-1) and 0.26 μg L(-1), and PNEC(SSD)s were 77 μg L(-1), 197 μg L(-1) and 10 μg L(-1), respectively for 2,4-DCP; 2,4,6-TCP; and PCP respectively. Based on the aquatic conditions of the Taihu Lake, the derived site-specific PNEC(AQUATOX)s were 15 μg L(-1), 67 μg L(-1) and 4 μg L(-1), respectively. In general, the PNECs for three chlorophenols derived from different approaches followed the declined order of PNEC(SSD) > PNEC(AQUATOX) > PNEC(AF). The ratios of PNEC(AF) to PNEC(SSD) and PNEC(AQUATOX) to PNEC(SSD) for three chlorophenols were 0.013-0.028 and 0.19-0.4, respectively. It indicated that PNECs obtained using different approaches may vary and the one based on the AF was the lowest. Therefore, PNEC(AF) can be seen as overprotective. The PNEC(AQUATOX) values for three chlorophenols were less than the corresponding PNEC(SSD) values, mostly because the indirect effects were considered in the ecological model. PMID:20936560

  20. Degradation of Chlorophenols by Alcaligenes eutrophus JMP134(pJP4) in Bleached Kraft Mill Effluent

    OpenAIRE

    Valenzuela, J.; Bumann, U.; Cespedes, R.; Padilla, L.; Gonzalez, B

    1997-01-01

    The ability of Alcaligenes eutrophus JMP134(pJP4) to degrade 2,4-dichlorophenoxyacetic acid, 2,4,6-trichlorophenol, and other chlorophenols in a bleached kraft mill effluent was studied. The efficiency of degradation and the survival of strain JMP134 and indigenous microorganisms in short-term batch or long-term semicontinuous incubations performed in microcosms were assessed. After 6 days of incubation, 2,4-dichlorophenoxyacetate (400 ppm) or 2,4,6-trichlorophenol (40 to 100 ppm) were extens...

  1. Isolation of Pseudomonas pickettii strains that degrade 2,4,6-trichlorophenol and their dechlorination of chlorophenols.

    OpenAIRE

    Kiyohara, H.; Hatta, T; Ogawa, Y.; T Kakuda; H. Yokoyama; Takizawa, N

    1992-01-01

    Three strains of Pseudomonas pickettii that can grow with 2,4,6-trichlorophenol (2,4,6-TCP) as the sole source of carbon and energy were isolated from different mixed cultures of soil bacterial populations that had been acclimatized to 2,4,6-TCP. These strains released 3 mol of chloride ion from 1 mol of 2,4,6-TCP during the complete degradation of the TCP. Of these strains, P. pickettii DTP0602 in high-cell-density suspension cultures dechlorinated various chlorophenols (CPs). Cells that wer...

  2. Toxicity assessment of 4-chlorophenol to aerobic granular sludge and its interaction with extracellular polymeric substances

    International Nuclear Information System (INIS)

    Highlights: • Toxicity of 4-CP to aerobic granular sludge process was evaluated. • 3D-EEM characterized the interaction between EPS and 4-CP. • Tryptophan was the main substance result in fluorescence quenching. • The mechanism of fluorescence quenching belongs to static quenching. - Abstract: The main objective of this study was to evaluate the toxicity of 4-chlorophenol (4-CP) to aerobic granular sludge in the process of treating ammonia rich wastewater. In the short-term exposure of 4-CP of 5 and 10 mg/L, ammonia nitrogen removal efficiencies in the batch reactors decreased to 87.18 ± 2.81 and 41.16 ± 3.55%, which were remarkably lower than that of control experiment (99.83 ± 0.54%). Correspondingly, the respirometric activities of heterotrophic and autotrophic bacteria of aerobic granular sludge were significantly inhibited in the presence of 4-CP. Moreover, the main components of extracellular polymeric substances (EPS) including polysaccharides and proteins increased from 18.74 ± 0.29 and 22.57 ± 0.34 mg/g SS to 27.79 ± 0.51 and 24.69 ± 0.38 mg/g SS, respectively, indicating that the presence of 4-CP played an important role on the EPS production. Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy further showed that the intensities of EPS samples were obviously quenched with the increased of 4-CP concentrations. To be more detailed, synchronous fluorescence spectra indicated that the interaction between EPS and 4-CP was mainly caused by tryptophan residues. The mechanism of fluorescence quenching belongs to static quenching with a formation constant (KA) of 0.07 × 104 L/mol, implying the strong formation of EPS and 4-CP complex. The results could provide reliable and accurate information to determine the potential toxicity of 4-CP on the performance of aerobic granular sludge system

  3. Probabilistic ecological risk assessment for three chlorophenols in surface waters of China

    Institute of Scientific and Technical Information of China (English)

    Liqun Xing; Hongling Liu; John P. Giesy; Xiaowei Zhang; Hongxia Yu

    2012-01-01

    Individual and combined assessment of risks of adverse effects to aquatic ecosystems of three chlorophenols (CPs),including 2,4-dichlorophenol (2,4-DCP),2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP),were conducted.A probabilistic approach based on the concentrations of CPs in surface waters of China was used to determine the likelihood of adverse effects.The potential risk of CPs in surface waters of China was determined to be of concern,especially PCP and mixtures of CPs.The risks of adverse effects were examined as the joint probabilities of exposure and response.The joint probability for PCP was 0.271 in the worst case and 0.111 in the median case,respectively.Based on the cumulative probability,5% of aquatic organisms included in the assessment would be affected 21.36% of the time in the worst case and 5.99% of the time in median case,respectively.For the mixtures of CPs,the joint probability were 0.171 in the worst case and 0.503 in median case,respectively and 5% of species would be affected 49.83% of the time for the worst case and 12.72% in the median case,respectively.Risks of effects of the individual CPs,2,4-DCP and 2,4,6-TCP were deemed to be acceptable with a overlapping probability of < 0.1 with 5% of species being affected less than 4% of the time.

  4. Fluorescence resonance energy transfer in AOT/4-chlorophenol/m-xylene organogels

    Energy Technology Data Exchange (ETDEWEB)

    Dandapat, Manika; Mandal, Debabrata, E-mail: dmandal.chemistry@gmail.com

    2015-06-15

    Fluorescence Resonance Energy Transfer (FRET) between donor coumarins (C102 and C153) and acceptor Rhodamine 6G were studied in AOT/4-chlorophenol/m-xylene organogels. The gel comprises a three-dimensional network of fiber bundles trapping the m-xylene solvent. Each fiber is an aggregate of several strands, and each strand consists of a central columnar stack of the phenols, surrounded by AOT headgroups. Our acceptor is ionic so that it was concentrated near the polar center of the strand, while the neutral donors were likely distributed over a wider region. With C153 as donor, clear evidence of FRET (time-constant~100 ps) was found, which indicated that the donor and acceptor may reside in neighboring strands within the same fiber. However, with C102 as donor, FRET probably occurred over an ultrashort, sub-picosecond time-scale suggesting that the donor and acceptor in this case resided in close vicinity. Thus, C102 tends to localize near the polar centre of the strands, compared to the more hydrophobic C153, which prefers to occupy the relatively non-polar peripheral regions of the strands and fibers. - Highlights: • FRET between coumarin donors and Rhodamine 6G acceptor studied in AOT organogels. • With Coumarin 153 donor, a ~100 ps FRET component detected in both donor and acceptor fluorescence. • With Coumarin 102 donor, FRET component too short to be detected with a time-resolution of ~70 ps. • The FRET rates reveal crucial differences in donor–acceptor distances for the two coumarin donors.

  5. Optimization of some experimental parameters in the electro membrane extraction of chlorophenols from seawater.

    Science.gov (United States)

    Lee, Jingyi; Khalilian, Faezeh; Bagheri, Habib; Lee, Hian Kee

    2009-11-01

    An electro membrane extraction (EME) methodology was utilized to study the isolation of some environmentally important pollutants, such as chlorophenols, from aquatic media based upon the electrokinetic migration process. The analytes were transported by application of an electrical potential difference over a supported liquid membrane (SLM). A driving force of 10V was applied to extract the analytes through 1-octanol, used as the SLM, into a strongly alkaline solution. The alkaline acceptor solution was subsequently analyzed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. The parameters influencing electromigration, including volumes and pH of the donor and acceptor phases, the organic solvent used as the SLM, and the applied voltage and its duration, were investigated to find the most suitable extraction conditions. Since the developed method showed a rather high degree of selectivity towards pentachlorophenol (PCP), validation of the method was performed using this compound. An enrichment factor of 23 along with acceptable sample clean-up was obtained for PCP. The calibration curve showed linearity in the range of 0.5-1000ng/mL with a coefficient of estimation corresponding to 0.999. Limits of detection and quantification, based on signal-to-noise ratios of 3 and 10, were 0.1 and 0.4ng/mL, respectively. The relative standard deviation of the analysis at a PCP concentration of 0.5ng/mL was found to be 6.8% (n=6). The method was also applied to the extraction of this contaminant from seawater and an acceptable relative recovery of 74% was achieved at a concentration level of 1.0ng/mL. PMID:19782990

  6. Electrochemical Characterization and Determination of Phenol and Chlorophenols by Voltammetry at Single Wall Carbon Nanotube/Poly(3,4-ethylenedioxythiophene) Modified Screen Printed Carbon Electrode

    Science.gov (United States)

    Negash, Negussie; Alemu, Hailemichael; Tessema, Merid

    2015-01-01

    Screen printed carbon electrode (SPCE) has been modified with single wall carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) composites for the determination of phenol and chlorophenols (phenol, 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol). The effect of the modifiers on the electrode characteristics was evaluated and the responses were optimized for the voltammetric determination of phenol and chlorophenols. The parameters affecting the responses such as pH, scan rate, and stability were studied. The analytical performance of the SWCNT/PEDOT/SPCE using cyclic voltammetry was tested and found to be impressive. Under these conditions, the designed electrode showed a good performance for the voltammetric measurements of the phenolic compounds. The modified SPCE, when it is compared with other enzymatic and nonenzymatic sensors, showed a wider dynamic range for the detection of the phenolic compounds. The modified SPCE was used for the quantification of phenol in water samples. The results suggest that the method is quite useful for analyzing and monitoring phenols and chlorophenols. PMID:27347519

  7. Trace analysis of chlorophenols in river water samples by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, M.; Ishii, Y.; Okanouchi, N.; Sakui, N.; Ito, R.; Inoue, K.; Nakazawa, H. [Hoshi Univ., Tokyo (Japan). Dept. of Analytical Chemistry, Faculty of Pharmaceutical Sciences; Saito, K. [Saitama Institute of Public Health, Saitama (Japan). Dioxin Research Group

    2004-09-15

    Many analytical methods for the determination of chlorophenols in water samples have been reported including gas chromatography-mass spectrometry (GC-MS). However, GC-MS was initially used for the determination of phenol compounds even though derivatization was required. The derivatization leads to sharper peaks and hence to better separation and higher sensitivity for the phenols. However, the derivatization faces the risk of contamination and hence an overestimation of chlorophenols concentration. In order to overcome these problems, in situ derivatization has been developed, which involves the simple addition of a reagent to a liquid sample. Recently, a new sorptive extraction technique that uses a stir bar coated with polydimethylsiloxane (PDMS) was developed. The technique is known as stir bar sorptive extraction (SBSE). We already reported that determination of 4-tert-octylphenol (OP) and 4-nonylphenol (NP) in river water4 and body fluid samples by using SBSE. In addition, SBSE with in situ derivatization has been successfully used in the determination of bisphenol A (BPA) in human body fluid samples6 and phenolic xenoestrogens in river water samples. The aim of this study is to determine trace amounts of chlorophenols in water samples by SBSE with in situ derivatization, followed by thermal desorption (TD)-GC-MS. The developed method was applied to determination of chlorophenols in river water samples.

  8. Fabrication of a novel hydrophobic/ion-exchange mixed-mode adsorbent for the dispersive solid-phase extraction of chlorophenols from environmental water samples.

    Science.gov (United States)

    Gao, Li; Wei, Yinmao

    2016-08-01

    A novel mixed-mode adsorbent was prepared by functionalizing silica with tris(2-aminoethyl)amine and 3-phenoxybenzaldehyde as the main mixed-mode scaffold due to the presence of the plentiful amino groups and benzene rings in their molecules. The adsorption mechanism was probed with acidic, natural and basic compounds, and the mixed hydrophobic and ion-exchange interactions were found to be responsible for the adsorption of analytes. The suitability of dispersive solid-phase extraction was demonstrated in the determination of chlorophenols in environmental water. Several parameters, including sample pH, desorption solvent, ionic strength, adsorbent dose, and extraction time were optimized. Under the optimal extraction conditions, the proposed dispersive solid-phase extraction coupled with high-performance liquid chromatography showed good linearity range and acceptable limits of detection (0.22∽0.54 ng/mL) for five chlorophenols. Notably, the higher extraction recoveries (88.7∽109.7%) for five chlorophenols were obtained with smaller adsorbent dose (10 mg) and shorter extraction time (15 min) compared with the reported methods. The proposed method might be potentially applied in the determination of trace chlorophenols in real water samples. PMID:27420911

  9. The role of CuCl on the mechanism of dibenzo-p-dioxin formation from poly-chlorophenol precursors: A computational study.

    Science.gov (United States)

    Fernández Pulido, Yoana; Suárez, Ernesto; López, Ramón; Menéndez, M Isabel

    2016-02-01

    A computational study is performed for the elucidation of the role played by CuCl in the condensation of two polychlorophenol molecules to yield PCDDs. The mechanism found consists of six sequential steps, which allow the final recuperation of the CuCl molecule, and applies for phenol molecules with an ortho chlorine. In the temperature range of 453-473 K (previously reported as adequate to diminish PCDDs formation in the post-combustion area), CuCl is able to softly retain chlorophenol molecules, mainly those less chlorinated. After a first HCl release, Cu(I) remains bonded to phenol oxygen atom, thus avoiding the formation of phenoxy radicals and the subsequent radical processes. A temperature raise up to 1200 K destabilizes the initial CuCl-chlorophenol complexes and causes that the rate limiting step change from the formation of the first oxygen bridge to HCl elimination. It has been checked that tetra and penta-chlorophenols undergo essentially the same reaction process of 2-chlorophenol. In view of our results and trying to arrive at a practical way to diminish the rate of formation of PCDDs, we propose that an extra addition of powdered CuCl to the post-combustion zone, cooled down to temperatures lower than 473 K, could act as an inhibitor in the formation of these pollutants. PMID:26684925

  10. FORMATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS FROM A MIXTURE OF CHLOROPHENOLS OVER FLY ASH: INFLUENCE OF WATER VAPOR

    Science.gov (United States)

    To offer a polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) parameter for plant operation control, the on-line estimation of PCDD/Fs emissions by surrogates like chlorophenols is useful. Formation of PCDD/Fs over fly ash was studied in an isothermal (310 degree...

  11. Effect of Sb dopant amount on the structure and electrocatalytic capability of Ti/Sb-SnO2 electrodes in the oxidation of 4-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ti/Sb-SnO2 anodes were prepared by thermal decomposition to examine the influence of the amount of Sb dopant on the structure and electrocatalytic capability of the electrodes in the oxidation of 4-chlorophenol. The physicochemical properties of the Sb-SnO2 coating were markedly influenced by different amounts of Sb dopant. The electrodes, which contained 5% Sb dopant in the coating, presented a much more homogenous surface and much smaller mud-cracks, compared with Ti/Sb-SnO2 electrodes containing 10% or 15% Sb dopant, which exibited larger mud cracks and pores on the surface. However, the main microstructure remained unchanged with the addition of the Sb dopant. No new crystal phase was observed by X-ray diffraction (XRD). The electrochemical oxidation of 4-chlorophenol on the Ti/SnO2 electrode with 5% Sb dopant was inclined to electrochemical combustion; while for those containing more Sb dopant, intermediate species were accumulated. The electrodes with 5% Sb dopant showed the highest efficiency in the bulk electrolysis of 4-chlorophenol at a current density of 20 mA/cm2 for 180 min; and the removal rates of 4-chlorophenol and COD were 51.0% and 48.9%, respectively.

  12. Application of multicriteria decision analysis in solvent type optimization for chlorophenols determination with a dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Bigus, Paulina; Namieśnik, Jacek; Tobiszewski, Marek

    2016-05-13

    This study presents a novel support tool for the optimization and development of analytical methods. The tool is based on multi-criteria decision analysis (MCDA), namely the Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS), that allows users to rank possible solutions according to their requirements. In this study, we performed rankings of pairs of eight extraction and three dispersive solvents used in DLLME for chlorophenols extraction from water samples. The first ranking involved sensitivity and precision of the method for each of the nine chlorophenols. The tool is a quantitative solution to the common analytical problem that the change of analytical performance results in better performance for some analytes and worse for others. The second ranking included the assessment of the greenness of each pair of solvents, based on toxicological, ecotoxicological and environmental persistence criteria. The third ranking was based on a combination of sensitivity, precision and greenness criteria. Heptane as an extraction solvent and acetone as a dispersive solvent were selected as the most appropriate ones. The TOPSIS tool is a successful, easy to implement, incorporation of green analytical chemistry values to analytical method optimization. PMID:27083262

  13. Partitioning of chloroaromatic compounds between the aqueous phase and dissolved and particulate soil organic matter at chlorophenol contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    Frankki, Sofia [Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umea (Sweden); Persson, Ylva [Environmental Chemistry, Department of Chemistry, Umea University, SE-901 87 Umea (Sweden); Shchukarev, Andrei [Inorganic Chemistry, Department of Chemistry, Umea University, SE-901 87 Umea (Sweden); Tysklind, Mats [Environmental Chemistry, Department of Chemistry, Umea University, SE-901 87 Umea (Sweden); Skyllberg, Ulf [Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umea (Sweden)]. E-mail: ulf.skyllberg@sek.slu.se

    2007-07-15

    The retention and mobility of hydrophobic organic contaminants (HOCs) in soil is mainly determined by hydrophobic partitioning to dissolved and particulate organic matter (DOM and POM, respectively). The aqueous phase, DOM, and POM fractions were extracted and separated from soils at three sites contaminated with technical chlorophenol formulations. Concentrations of chlorophenols (CP), polychlorinated phenoxyphenols (PCPP), polychlorinated diphenyl ethers (PCDE) and polychlorinated dibenzo-p-dioxins and furans (PCDD/F) were determined. The partitioning to POM, in relation to DOM, increased in all three soils with increasing hydrophobicity in the order CP < PCPP {approx} PCDE {approx} PCDF < PCDD. Differences in partitioning to DOM (log K {sub DOC}) and POM (log K {sub POC}) could not be explained by differences in gross organic C chemistry. Black carbon did not contribute significantly to the sorption of PCDDs, whereas >70% wood fibre in one soil resulted in a decrease of log K {sub POC} of 0.5 units for CPs and PCDDs. We conclude that log K {sub OC} for both DOM and POM need to be explicitly determined when the retention and mobility of HOCs is described and modelled in soils. - Increasing hydrophobicity of organic compounds increases the partitioning to particulate natural organic matter relative to dissolved natural organic matter.

  14. Dioxins and other products from the gas-phase oxidation of 2-chlorophenol over the range 450-900 C

    Energy Technology Data Exchange (ETDEWEB)

    Sawerysyn, J.P.; Briois, C.; Visez, N.; Baillet, C. [Lille-1 Univ. (France). Physicochimie des Processus de Combustion et de l' Atmosphere - UMR-CNRS

    2004-09-15

    Introduction Numerous laboratory studies have been devoted to thermal degradation processes of chlorinated aromatics because they represent the major part of toxic compounds in hazardous wastes. Most previous studies have concentrated on the formation of seventeen toxicologically significant 2,3,7,8-substituted congeners of polychlorodibenzodioxins and polychlorodibenzofurans (PCDD/Fs, also commonly called dioxins) which have been found in both the gaseous and particle phase of effluents emitted from both industrial and distributed combustion processes. To our best knowledge, only very few authors have paid some attention on the specific analysis of low chlorinated PCDD/Fs and potential precursors of PCDD/Fs such as chlorobenzenes and chlorophenols which may also be further sources of highly chlorinated PCDD/Fs. As key intermediates in the formation pathways of PCDD/Fs, polychlorophenols (PCP) were largely investigated but relatively few studies were devoted to the pyrolysis or oxidation of monochlorophenols (MCP) in the gas phase at high temperatures. In this paper, we report analytical results on the major stable products of the high-temperature, homogeneous gas-phase oxidation of 2-chlorophenol (2-CP). The concentration profiles of 2-CP, major organic non-PCDD/F products, major PCDD/Fs and carbon oxides are determined as a function of temperature and residence time over ranges relevant to waste incinerators. Our objective is to contribute to a better understanding of the homogeneous gas-phase processes responsible for the formation / destruction of dioxins from organic precursors using a detailed chemical mechanism experimentally validated.

  15. Theoretical Mechanistic and Kinetic Studies on Homogeneous Gas-Phase Formation of Polychlorinated Naphthalene from 2-Chlorophenol as Forerunner

    Directory of Open Access Journals (Sweden)

    Fei Xu

    2015-10-01

    Full Text Available Polychlorinated naphthalenes (PCNs are dioxins-like compounds and are formed along with polychlorinated dibenzo-p-dioxins (PCDDs and polychlorinated dibenzofurans (PCDFs in thermal and combustion procedures. Chlorophenols (CPs are the most important forerunners of PCNs. A comprehensive comprehension of PCN formation procedure from CPs is a precondition for reducing the discharge of PCNs. Experiments on the formation of PCNs from CPs have been hindered by PCN toxicity and short of precise detection methods for active intermediate radicals. In this work, PCN formation mechanism in gas-phase condition from 2-chlorophenol (2-CP as forerunner was studied by quantum chemistry calculations. Numbers of energetically advantaged formation routes were proposed. The rate constants of key elementary steps were calculated over 600–1200 K using canonical variational transition-state theory (CVT with small curvature tunneling contribution (SCT method. This study illustrates formation of PCNs with one chlorine atom loss from 2-CP is preferred over that without chlorine atom loss. In comparison with formation of PCDFs from 2-CP, PCN products are less chlorinated and have lower formation potential.

  16. Partitioning of chloroaromatic compounds between the aqueous phase and dissolved and particulate soil organic matter at chlorophenol contaminated sites

    International Nuclear Information System (INIS)

    The retention and mobility of hydrophobic organic contaminants (HOCs) in soil is mainly determined by hydrophobic partitioning to dissolved and particulate organic matter (DOM and POM, respectively). The aqueous phase, DOM, and POM fractions were extracted and separated from soils at three sites contaminated with technical chlorophenol formulations. Concentrations of chlorophenols (CP), polychlorinated phenoxyphenols (PCPP), polychlorinated diphenyl ethers (PCDE) and polychlorinated dibenzo-p-dioxins and furans (PCDD/F) were determined. The partitioning to POM, in relation to DOM, increased in all three soils with increasing hydrophobicity in the order CP DOC) and POM (log K POC) could not be explained by differences in gross organic C chemistry. Black carbon did not contribute significantly to the sorption of PCDDs, whereas >70% wood fibre in one soil resulted in a decrease of log K POC of 0.5 units for CPs and PCDDs. We conclude that log K OC for both DOM and POM need to be explicitly determined when the retention and mobility of HOCs is described and modelled in soils. - Increasing hydrophobicity of organic compounds increases the partitioning to particulate natural organic matter relative to dissolved natural organic matter

  17. Visible light responsive N-F-codoped TiO2 photocatalysts for the degradation of 4-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Li; Haidong Zhang; Xuxu Zheng; Zhongyi Yin; Le Wei

    2011-01-01

    N-F-codoped TiO2 (NFTO) photocatalysts were synthesized by a simple sol-gel process with tetrabutyl titanate (Ti(OBu)4) as the precursor of TiO2 and ammonium fluoride (NH4F) as the source of N and F.The synthesized photocatalysts were investigated by X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and photodegradation reaction tests of 4-chlorophenol under visible light irradiation to understand the relationship between the structure of NFTO catalyst and corresponding photocatalytic activity.The crystal phase and particle size of catalysts were found to be largely affected by the calcination temperature.In addition,N-F-codoping could inhibit phase transition of TiO2 from anatase to rutile.The presence of N and F atoms in the lattice of TiO2 is responsible for the visible light catalytic activity.In UV-Vis DRS tests,the spectrum of NFTO exhibited red shift compared with Degussa P25 and the band gap was reduced to around 2.92 eV.Under optimal calcination temperature and dopant concentration conditions,the NFTO photocatalyst exhibited the highest activity in the photodegradation reaction tests of 4-chlorophenol under visible light irradiation with a degradation rate of 75.84%.Besides,the 5-recycle test showed that NFTO photocatalyst could be reused and its activity kept stable under visible light irradiation.

  18. Associations of prenatal exposure to five chlorophenols with adverse birth outcomes.

    Science.gov (United States)

    Guo, Jianqiu; Wu, Chunhua; Lv, Shenliang; Lu, Dasheng; Feng, Chao; Qi, Xiaojuan; Liang, Weijiu; Chang, Xiuli; Xu, Hao; Wang, Guoquan; Zhou, Zhijun

    2016-07-01

    Exposures to chlorophenols (CPs) have been linked with adverse health effects on wildlife and humans. This study aimed to evaluate prenatal exposure to five CP compounds using maternal urinary concentrations during pregnancy and the potential associations with birth outcomes of their infants at birth. A total of 1100 mother-newborn pairs were recruited during June 2009 to January 2010 in an agricultural region, China. Urinary concentrations of five CPs from dichlorophenol (DCP) to pentachlorophenol (PCP), namely, 2,5-DCP, 2,4-DCP, 2,4,5-trichlorophenol (2,4,5-TCP), 2,4,6-TCP and PCP, were measured using large-volume-injection gas chromatography-tandem mass spectrometry (LVI-GC-MS-MS), and associations between CP levels and weight, length as well as head circumference at birth were examined. Median urinary creatinine-adjusted concentrations of 2,5-DCP, 2,4-DCP, 2,4,5-TCP, 2,4,6-TCP and PCP were 3.34 μg/g, 1.03 μg/g, < LOD, 1.78 μg/g and 0.39 μg/g creatinine, respectively. We found lower birth weight 30 g [95% confidence interval (CI): -57, -3; p = 0.03] for per SD increase in log10-transformed concentrations of 2,4,6-TCP and lower birth weight 37 g (95% CI: -64, -10; p = 0.04) for PCP, respectively. Similarly, head circumference decrease in associations with creatinine-corrected 2,4,6-TCP and PCP concentrations were also achieved. Considering sex difference, the associations of lower birth weight were only found among male neonates, while head circumference was associated with 2,4-DCP and 2,5-DCP only found among female neonates. This study showed significant negative associations between CPs exposure and reduction in neonatal anthropometric measures. The biological mechanisms concerning CPs exposure on fetal growth deserved further investigations. PMID:27131805

  19. Fate of alkylphenols, chlorophenols and bisphenol A in the Lake Shihwa, Korea

    International Nuclear Information System (INIS)

    Full text: Surface water, suspended particles in surface water and sediment samples from the brackish lake, Shihwa, and its surrounding creeks were collected during Aug. 2001 to May 2004 in Korea. Representative endocrine disrupting chemicals (EDCs) such as alkylphenols, chlorophenols and bisphenol A, were determined from each matrix by GC/MS. Among them, alkylphenol compounds were recorded as the major pollutants affecting Lake Shihwa water quality. High concentration of alkylphenols were measured in those matrices in and around industrial complexes. The levels decreased gradually with distance from the industrial areas. Though alkylphenols concentration in sediment varied from that of water and suspended particle, high concentrations were generally found in industrial area and in central part of the Lake Shihwa. Concentrations of nonylphenol from industrial area were similar or higher than US and EU regulatory value which is 1 μg/L. Spatial and seasonal variation of alkylphenol in dissolved water and suspended particulate were similar but not in the sediment. The alkylphenol concentration was the highest in summer and the lowest in winter. There is no annual correlation on the levels of alkylphenol in water and particulate. Phenolic compounds are continuously discharged into Lake Shihwa from surrounding industries and hence the input of alkylphenols increases in time. Alkylphenol compound s were continuously produced by biodegradation of alkylphenol polyethoxylate and it was accumulated in the sediments by adsorption. Nonylphenol and bisphenol A were the major endocrine disrupting chemicals determined in the Lake Shihwa. The contents of nonylphenol and bisphenol A in dissolved water, suspended particle and sediment are 60, 70, 90% and 35, 25, 8%, respectively. The levels of these chemicals measured in creeks were about 25 times higher than those in Lake Shihwa. In order to identify the source and behavior of alkylphenols in the environment, the relationship

  20. Toxicity assessment of 4-chlorophenol to aerobic granular sludge and its interaction with extracellular polymeric substances

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Dong; Wang, Yifan; Wang, Xiaodong; Li, Mengting; Han, Fei; Ju, Luyu; Zhang, Ge; Shi, Li; Li, Kai; Wang, Bingfeng [School of Resources and Environmental Sciences, University of Jinan, Jinan 250022 (China); Du, Bin, E-mail: dubin61@gmail.com [School of Resources and Environmental Sciences, University of Jinan, Jinan 250022 (China); Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Wei, Qin [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2015-05-30

    Highlights: • Toxicity of 4-CP to aerobic granular sludge process was evaluated. • 3D-EEM characterized the interaction between EPS and 4-CP. • Tryptophan was the main substance result in fluorescence quenching. • The mechanism of fluorescence quenching belongs to static quenching. - Abstract: The main objective of this study was to evaluate the toxicity of 4-chlorophenol (4-CP) to aerobic granular sludge in the process of treating ammonia rich wastewater. In the short-term exposure of 4-CP of 5 and 10 mg/L, ammonia nitrogen removal efficiencies in the batch reactors decreased to 87.18 ± 2.81 and 41.16 ± 3.55%, which were remarkably lower than that of control experiment (99.83 ± 0.54%). Correspondingly, the respirometric activities of heterotrophic and autotrophic bacteria of aerobic granular sludge were significantly inhibited in the presence of 4-CP. Moreover, the main components of extracellular polymeric substances (EPS) including polysaccharides and proteins increased from 18.74 ± 0.29 and 22.57 ± 0.34 mg/g SS to 27.79 ± 0.51 and 24.69 ± 0.38 mg/g SS, respectively, indicating that the presence of 4-CP played an important role on the EPS production. Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy further showed that the intensities of EPS samples were obviously quenched with the increased of 4-CP concentrations. To be more detailed, synchronous fluorescence spectra indicated that the interaction between EPS and 4-CP was mainly caused by tryptophan residues. The mechanism of fluorescence quenching belongs to static quenching with a formation constant (K{sub A}) of 0.07 × 10{sup 4} L/mol, implying the strong formation of EPS and 4-CP complex. The results could provide reliable and accurate information to determine the potential toxicity of 4-CP on the performance of aerobic granular sludge system.

  1. Evaluation of exposure to organophosphate, carbamate, phenoxy acid, and chlorophenol pesticides in pregnant women from 10 Caribbean countries.

    Science.gov (United States)

    Forde, Martin S; Robertson, Lyndon; Laouan Sidi, Elhadji A; Côté, Suzanne; Gaudreau, Eric; Drescher, Olivia; Ayotte, Pierre

    2015-09-01

    Pesticides are commonly used in tropical regions such as the Caribbean for both household and agricultural purposes. Of particular concern is exposure during pregnancy, as these compounds can cross the placental barrier and interfere with fetal development. The objective of this study was to evaluate exposure of pregnant women residing in 10 Caribbean countries to the following commonly used classes of pesticides in the Caribbean: organophosphates (OPs), carbamates, phenoxy acids, and chlorophenols. Out of 438 urine samples collected, 15 samples were randomly selected from each Caribbean country giving a total of 150 samples. Samples were analyzed for the following metabolites: six OP dialkylphosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP)]; two carbamate metabolites [2-isopropoxyphenol (2-IPP) and carbofuranphenol]; one phenoxy acid 2,4-dichlorophenoxyacetic acid (2,4-D); and five chlorophenols [2,4-dichlorophenol (DCP), 2,5-dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (TCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP)]. OP metabolites were consistently detected in ≥60% of the samples from Antigua and Barbuda, Bermuda, and Jamaica. Of the carbamate metabolites, 2-IPP was detected in seven of the 10 Caribbean countries with a detection frequency around 30%, whereas carbofuranphenol was detected in only one sample. The detection frequency for the phenoxy acid 2,4-D ranged from 20% in Grenada to a maximum of 67% in Belize. Evidence of exposure to chlorophenol pesticides was also established with 2,4-DCP by geometric means ranging from 0.52 μg L(-1) in St Lucia to a maximum of 1.68 μg L(-1) in Bermuda. Several extreme concentrations of 2,5-DCP were detected in four Caribbean countries-Belize (1100 μg L(-1)), Bermuda (870 μg L(-1)), Jamaica (1300 μg L(-1)), and St Kitts and Nevis (1400 μg L(-1

  2. A sensitive electrochemical chlorophenols sensor based on nanocomposite of ZnSe quantum dots and cetyltrimethylammonium bromide

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianjun; Li, Xiao [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Yang, Ran, E-mail: yangran@zzu.edu.cn [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Qu, Lingbo, E-mail: qulingbo@zzu.edu.cn [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001 (China); Harrington, Peter de B. [Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Clippinger Laboratories, OHIO University, Athens, OH 45701-2979 (United States)

    2013-12-04

    Graphical abstract: A very sensitive and simple electrochemical sensor for chlorophenols (CPs) based on nanocomposite of cetyltrimethylammonium bromide (CTAB) and ZnSe quantum dots (ZnSe–CTAB) through electrostatic self-assembly technology was built for the first time. The nanocomposite of ZnSe–CTAB introduced a favorable access for the electron transfer and showed excellent electrocatalytic activity for the oxidation of CPs. -- Highlights: •Nanocomposite based ZnSe QDs and CTAB was prepared and characterized. •A novel electrochemical sensor for the determination of CPs was built. •The proposed sensor was more sensitive, simple and environment-friendly. -- Abstract: In this work, a very sensitive and simple electrochemical sensor for chlorophenols (CPs) based on a nanocomposite of cetyltrimethylammonium bromide (CTAB) and ZnSe quantum dots (ZnSe–CTAB) through electrostatic self-assembly technology was built for the first time. The composite of ZnSe–CTAB introduced a favorable access for the electron transfer and gave superior electrocatalytic activity for the oxidation of CPs than ZnSe QDs and CTAB alone. Differential pulse voltammetry (DPV) was used for the quantitative determination of the CPs including 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP). Under the optimum conditions, the peak currents of the CPs were proportional to their concentrations in the range from 0.02 to 10.0 μM for 2-CP, 0.006 to 9.0 μM for 2,4-DCP, and 0.06 to 8.0 for PCP. The detection limits were 0.008 μM for 2-CP, 0.002 μM for 2,4-DCP, and 0.01 μM for PCP, respectively. The method was successfully applied for the determination of CPs in waste water with satisfactory recoveries. This ZnSe–CTAB electrode system provides operational access to design environment-friendly CPs sensors.

  3. Determination of chlorophenols in landfill leachate using headspace sampling with ionic liquid-coated solid-phase microextraction fibers combined with gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Tse-Tsung; Chen, Chung-Yu [Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan (China); Li Zuguang [Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan (China); College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014, Zhejiang (China); Yang, Thomas Ching-Cherng [Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 82444, Taiwan (China); Lee, Maw-Rong, E-mail: mrlee@dragon.nchu.edu.tw [Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan (China)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Ionic liquid (IL), ([C{sub 4}MIM][PF{sub 6}]), was rapid synthesized by microwave radiation. Black-Right-Pointing-Pointer Trace chlorophenols in landfill leachate were extract by SPME coated IL. Black-Right-Pointing-Pointer The IL-coated SPME-GC/MS method is low-cost, solvent-free and sensitive. - Abstract: A new microextraction technique based on ionic liquid solid-phase microextraction (IL-SPME) was developed for determination of trace chlorophenols (CPs) in landfill leachate. The synthesized ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C{sub 4}MIM][PF{sub 6}]), was coated onto the spent fiber of SPME for extraction of trace CPs. After extraction, the absorbed analytes were desorbed and quantified using gas chromatography-mass spectrometry (GC/MS). The term of the proposed method is as ionic liquid-coated of solid-phase microextraction combined with gas chromatography-mass spectrometry (IL-SPME-GC/MS). No carryover effect was found, and every laboratory-made ionic liquids-coated-fiber could be used for extraction at least eighty times without degradation of efficiency. The chlorophenols studied were 2,4-dichlorophenol (2,4-DP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP). The best results of chlorophenols analysis were obtained with landfill leachate at pH 2, headspace extraction for 4 min, and thermal desorption with the gas chromatograph injector at 240 Degree-Sign C for 4 min. Linearity was observed from 0.1 to 1000 {mu}g L{sup -1} with relative standard deviations (RSD) less than 7% and recoveries were over 87%. The limit of detection (LOD) for pentachlorophenol was 0.008 {mu}g L{sup -1}. The proposed method was tested by analyzing landfill leachate from a sewage farm. The concentrations of chlorophenols were detected to range from 1.1 to 1.4 {mu}g L{sup -1}. The results demonstrate that the IL-SPME-GC/MS method is highly effective in

  4. Electrocatalytic oxidation of chlorophenols by electropolymerised nickel(II) tetrakis benzylmercapto and dodecylmercapto metallophthalocyanines complexes on gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Agboola, Bolade [Chemistry Department, Rhodes University, Grahamstown 6140 (South Africa); Nyokong, Tebello [Chemistry Department, Rhodes University, Grahamstown 6140 (South Africa)]. E-mail: t.nyokong@ru.ac.za

    2007-04-20

    This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecylmercapto (NiTDMPc) metallophthalocyanine complexes films on gold electrodes for the electrochemical oxidation of 4-chlorophenol (4-CP) and 2,4,5-trichlorophenol (TCP). Both NiTBMPc and NiTDMPc complexes were successfully deposited on gold electrodes by electropolymerisation. The films were electro-transformed in aqueous 0.1 M NaOH solution to the 'O-Ni-O oxo' bridged form. For both complexes, films with different thickness were prepared and characterised by electrochemical impedance and UV-vis (on indium tin oxide) spectroscopies and the results showed typical behaviour for modified electrodes with increasing charge transfer resistance values (R {sub p}) with polymer thickness. The poly-Ni(OH)NiPcs showed better catalytic activity than their poly-NiPcs counterparts.

  5. Determination of Chlorophenols in Water Samples Using Solid-Phase Extraction Enrichment Procedure and Gas Chromatography Analysis.

    Science.gov (United States)

    Ben Hassine, S; Hammami, B; Touil, S; Driss, M R

    2015-11-01

    Solid-phase extraction (SPE) procedure followed by derivatization and gas chromatography electron capture detection was evaluated for the determination of trace amounts of chlorophenols (CPs) in waters samples. Different parameters affecting extraction efficiency such as, volume of elution solvent, volume and pH of water sample, quantity of sorbent phase were studied and optimized. SPE was carried out on polystyrene-divinylbenzene (Bond Elut ENV) and high recoveries were obtained using 1000 mg of this cartridge for the treatment of 500 mL of acidified water sample. The described method was then tested on spiked tap, mineral, ground and surface water samples. The overall procedure provided limits of detection lower than 20 ng L(-1), recoveries of 70%-106% and an enrichment factor of 500 for the examined CPs in 500 mL water samples. Among the studied compounds, pentachlorophenol was detected in tap water at a concentration level of 0.06 µg L(-1). PMID:26067701

  6. Chlorophenols in tap water from wells and surface sources in Rio de Janeiro, Brazil: method validation and analysis

    Directory of Open Access Journals (Sweden)

    André Victor Sartori

    2012-01-01

    Full Text Available Two analytical methods were validated for determination of trichlorophenols, tetrachlorophenols and pentachlorophenol in drinking water. Limits of quantification were at least ten times lower than maximum permissible levels set by the Brazilian legislation, which are 200 ng mL-1 for 2,4,6-trichlorophenol and 9 ng mL-1 for pentachlorophenol. Chlorophenol levels were determined in tap water collected in the Municipality of Rio de Janeiro. 2,4,6-Trichlorophenol residues were detected in 36% of the samples, varying from 0.008 to 0.238 ng mL-1. All other analytes were below the limit of quantification. The validated methods showed to be suitable for application in routine quality control.

  7. DFT-B3LYP computations of electro and thermo molecular characteristics and mode of action of fungicides (chlorophenols).

    Science.gov (United States)

    Dixit, V; Yadav, R A

    2015-08-01

    Density functional theoretical (DFT) calculations of the pesticides; 2-chlorophenol (2-CP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) have been carried out using 6-311++G** basis set available on Gaussian-09 software in order to optimize the molecular structures. The optimized geometry of the molecules has been found to possess Cs symmetry. The charge transfer phenomena occurring in the molecules have been exhibited by (HOMO-LUMO) analysis. The molecular ESP values and mappings of electron density iso-surface with the molecular electrostatic potential (MEP), have been carried out to achieve the information of the size, shape, charge density distribution and site of chemical reactivity of the molecules. Thermo molecular characteristics have been computed to achieve essential environmental influence on the activities of fungicides. PMID:26144387

  8. Correlation between microbial diversity and toxicity of sludge treating synthetic wastewater containing 4-chlorophenol in sequencing batch reactors.

    Science.gov (United States)

    Zhao, Jianguo; Chen, Xiurong; Bao, Linlin; Bao, Zheng; He, Yixuan; Zhang, Yuying; Li, Jiahui

    2016-06-01

    The relationship between microbial diversity and sludge toxicity in the biotreatment of refractory wastewater was investigated. Synthetic wastewater containing 4-chlorophenol (4-CP) was treated by an activated sludge using a sequencing batch bioreactor (SBR). At the end of a single SBR cycle, a stable operation stage was reached when the 4-CP was not detected both in aqueous and sludge phases and the effluent COD was maintained at approximately 70 mg L(-1) for the blank and control sludge groups. Then, the diversity of the microorganisms and the sludge toxicity were measured. The results showed that the Microtox acute toxicity of the control sludge was higher than those of the blank sludge. The difference analysis of the microbial diversity between the blank and control sludge indicated that the sludge toxicity was closely related to microbial diversity. PMID:27016808

  9. Application of a diffusion-reaction kinetic model for the removal of 4-chlorophenol in continuous tank reactors.

    Science.gov (United States)

    Murcia, M D; Gómez, M; Bastida, J; Hidalgo, A M; Montiel, M C; Ortega, S

    2014-08-01

    A continuous tank reactor was used to remove 4-chlorophenol from aqueous solutions, using immobilized soybean peroxidase and hydrogen peroxide. The influence of operational variables (enzyme and substrate concentrations and spatial time) on the removal efficiency was studied. By using the kinetic law and the intrinsic kinetic parameters obtained in a previous work with a discontinuous tank reactor, the mass-balance differential equations of the transient state reactor model were solved and the theoretical conversion values were calculated. Several experimental series were used to obtain the values of the remaining model parameters by numerical calculation and using an error minimization algorithm. The model was checked by comparing the results obtained in some experiments (not used for the determination of the parameters) and the theoretical ones. The good concordance between the experimental and calculated conversion values confirmed that the design model can be used to predict the transient behaviour of the reactor.

  10. Chlorobenzenes, chlorophenols, PAHs and low chlorinated dioxin/furan as post-boiler toxicity indicators in municipal solid waste incinerators

    Energy Technology Data Exchange (ETDEWEB)

    Oh, J.E.; Gullett, B.; Ryan, S. [Environmental Protection Agency, Research Triangle Park, NC (United States); Touati, A. [AICADIS, Research Triangle Park, NC (United States)

    2004-09-15

    Numerous research studies have been conducted to establish indicator compounds for fast and less costly predictive monitoring of polychlorinated dibenzo-p-dioxin and furan (PCDD/F) toxic equivalent concentrations (TEQs). Many studies have shown that chlorobenzenes and chlorophenols had a good correlation with TEQ, suggesting that these compounds could be used as PCDD/F TEQ indicators. Good correlation results were reported between some low mono- to trichlorinated PCDD/F isomers and TEQ. Resonance enhanced multi-photon ionization (REMPI) with time of flight mass spectrometry (TOFMS) has shown the ability to monitor certain low chlorinated PCDD/F isomers and is, therefore, considered a promising on-line TEQ monitoring technique. However, there is still uncertainty in using these compounds as universal indicators because their relationships with TEQ may be plant- and operating-condition specific. Indeed, one study has shown that different correlations between low chlorinated dioxin/furan and TEQ existed in two incinerators. Given that indicator/TEQ relationships may be plant- and location (temperature) specific, past efforts to determine indicators using combined data from multiple facilities and multiple locations within a single facility that are limited in number of samples and species may be insufficient to determine robust indicators. The objective of this study is to determine indicator compounds based on intra-facility measurements under different operating conditions and to examine the effect of sampling position on potential indicator/TEQ relationships. An expanded indicator set, including chlorobenzenes (ClBzs), chlorophenols (ClPhs), polyaromatic hydrocarbons (PAHs) and low chlorinated dioxin/furan were analyzed to identify the relationship between these compounds and TEQ.

  11. The Pd-catalyzed hydrodechlorination of chlorophenols in aqueous solutions under mild conditions: A promising approach to practical use in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Xia Chuanhai, E-mail: chuanhaixia@gmail.com [Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003 (China); Liu Ying; Zhou Shiwei; Yang Cuiyun; Liu Sujing [Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003 (China); Xu Jie [Dalian Institute of Chemical Physics, CAS, Dalian, 116021 (China); Yu Junbao [Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003 (China); Chen Jiping; Liang Xinmiao [Dalian Institute of Chemical Physics, CAS, Dalian, 116021 (China)

    2009-09-30

    Catalytic hydrotreating of chlorophenols was carried out in water with Pd/C at 25 deg. C under atmospheric pressure. 1.0% (w/w) monocholophenols was completely dechlorinated within 60 min. Phenol, cyclohexanone and cyclohexanol were formed. In contrast to the dechlorination of monochlorophenols, the hydrogenation reaction of polychlorinated phenols became difficult and reaction rates were strongly dependent upon the number of the chlorine atoms. The solvent property had a considerably important influence on the dechlorination reaction. Water as a solvent showed more advantages than organic solvents. It was much easier to be hydrodechlorinated for chlorophenols in aqueous solutions. However, the presence of THF, dioxane, DMSO or DMF in water was disadvantageous to the reaction and easily to cause Pd/C deactivation. Additionally, when different halogenated organic compounds were present in aqueous solution, the dehalogenation reaction was the competitive hydrogenation process.

  12. Optimisation of the derivatisation reaction and subsequent headspace solid-phase microextraction method for the direct determination of chlorophenols in red wine.

    Science.gov (United States)

    Martínez-Uruñuela, Almudena; González-Sáiz, José María; Pizarro, Consuelo

    2004-09-10

    An acetylation reaction for the derivatisation of the three chlorophenols involved in cork taint was optimised using a Doehlert design for direct application in wine samples. In this first step, the optimum reaction pH, by adding different amounts of KHCO3, and the required quantity of derivatisation reagent were fixed. Then a series of parameters relevant for the headspace solid-phase microextraction process, such as desorption conditions, salt addition and agitation sample were evaluated. A simultaneous study of the type of fibre and extraction temperature was performed at five levels and based on the results obtained the rest of factors (sample volume and exposition time) that could potentially affect the extraction yields were optimised by a central composite design. According to the validation of the method, we propose here, to our knowledge, the first application of solid-phase microextraction for the direct analysis of chlorophenols in red wine samples. PMID:15481251

  13. CHLOROPHENOL DEGRADATION BY ELECTROCATALYSIS COMBINED WITH UV RADIATION%电催化与紫外光辐射降解氯酚

    Institute of Scientific and Technical Information of China (English)

    吴祖成; 叶倩; 周明华; 丛燕青

    2002-01-01

    @@ Chlorinated organic compounds, especially chlorophenols are well-known water priority pollutant family due to their toxicity and potential health hazard. As biological treatment processes for the degradation of chlorinated phenols have not been effective, various technologies and processes such as activated carbon adsorption[1], chemical oxidation[2], have been conventionally attempted for phenolic waster treatment. Recently, advanced oxidation processes (AOPs) have attracted a great deal of attention for treatment of phenolic wastewater, among these chemical oxidation ultraviolet (UV) oxidation system[3], anodic oxidation and indirect electro-oxidation have been widely studied[4]. Though a number of researchers worked on the degradation of chlorophenol by UV radiation or electrochemical processes, there are few reports on both methods for organic wastewater treatment. If these two processes can operate in harmony, the degradation efficiency would be enhanced.

  14. Investigating The Molecular Formation Ppoperties of 2-Acetylamino-6-Benzoyl-4-Chlorophenol Using The Semi Emprical Molecular Orbital Methods (PM3, AM1, MNDO)

    OpenAIRE

    Fatma BAYSEN

    2004-01-01

    In this study in order to the geometry optimization of the 2-acetylamino-6-benzoyl-4-chlorophenol crystal, which is used for forming analgesic and antienflamatuar medicine and of which crystal structure was determined using x-ray diffraction method, PM3, AM1 and MNDO semi emprical molecular orbital methods found in the HyperChem program were used. By the geometry optimization geometric parameters of the molecules having the minimum energy were found.These values which were theoretically obtai...

  15. Characterization of an Inducible Chlorophenol O-Methyltransferase from Trichoderma longibrachiatum Involved in the Formation of Chloroanisoles and Determination of Its Role in Cork Taint of Wines

    OpenAIRE

    Coque, Juan-José R.; Álvarez-Rodríguez, María Luisa; Larriba, Germán

    2003-01-01

    A novel S-adenosyl-l-methionine (SAM)-dependent methyltransferase catalyzing the O methylation of several chlorophenols and other halogenated phenols was purified 220-fold to apparent homogeneity from mycelia of Trichoderma longibrachiatum CECT 20431. The enzyme could be identified in partially purified protein preparations by direct photolabeling with [methyl-3H]SAM, and this reaction was prevented by previous incubation with S-adenosylhomocysteine. Gel filtration indicated that the Mr was 1...

  16. Cold Incineration of Chlorophenols in Aqueous Solution by Advanced Electrochemical Process Electro-Fenton. Effect of Number and Position of Chlorine Atoms on the Degradation Kinetics

    Science.gov (United States)

    Oturan, Nihal; Panizza, Marco; Oturan, Mehmet A.

    2009-09-01

    This study reports the kinetics of the degradation of several chlorophenols (CPs), such as monochlorophenols (2-chlorophenol and 4-chlorophenol), dichlorophenols (2,4-dichlorophenol and 2,6- dichlorophenol), trichlorophenols (2,3,5- trichlorophenol and 2,4,5-trichlorophenol), 2,3,5,6-tetrachlorophenol, and pentachlorophenol, by the electro-Fenton process using a carbon felt cathode and a Pt anode. The effect of number and the position of the chlorine atoms in the aromatic ring on the oxidative degradation rate was evaluated and discussed. The oxidation reaction of all the CPs with hydroxyl radicals evidenced a pseudo-first-order kinetics and the rate constant decreased with increasing the number of chlorine atoms. The absolute rate constant of second-order reaction kinetics between CPs and •OH was determined by the competition kinetics method in the range of (3.56-7.75) × 109 M-1 s-1 and follows the same sequence of the apparent rate constants. The mineralization of several CPs and of a mixture of all CPs under study was monitored by the total organic carbon (TOC) removal and the chlorine release during mineralization was followed by ion chromatography. Our results demonstrated that more chlorinated phenols are more difficult to mineralize; however for all the tested CPs, almost quantitative release of chloride ions was obtained after 6 h of treatment.

  17. Ethanol/Water extraction combined with solid-phase extraction and solid-phase microextraction concentration for the determination of chlorophenols in cork stoppers.

    Science.gov (United States)

    Insa, Sara; Besalú, Emili; Iglesias, Cristina; Salvadó, Victoria; Anticó, Enriqueta

    2006-02-01

    The appearance of 2,4,6-trichloroanisole (TCA) in cork stoppers is of great concern because it can cause off-flavors in bottled wine. To prevent this sensorial defect, there should not be any traces of 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP), or pentachlorophenol (PCP) in the finished corks, because they are the direct precursors of TCA. In the course of this study two methodologies based upon an extraction with ethanol/water mixtures to determine the chlorophenolic content in cork matrices were developed. The cork extract is preconcentrated using both solid-phase extraction and solid-phase microextraction methodologies. The latter was optimized by applying a full two-level factorial design. Finally, spiked ground corks at nanogram per gram levels of each chlorophenol were analyzed under optimal conditions and by applying both procedures. The obtained results demonstrate that chlorophenols can be detected in corks contaminated at the nanogram per gram level and, thus, these approaches can be successfully applied as quality control measures in the cork industry. PMID:16448159

  18. Development and validation of a simple thin-layer chromatographic method for the analysis of p-chlorophenol in treated wastewater

    Directory of Open Access Journals (Sweden)

    Tešić Živoslav

    2012-01-01

    Full Text Available A thin-layer chromatographic method with densitometric detection was established for quantification of p-chlorophenol in waste water. Degradation efficiency of p-chlorophenol was monitored after each treatment of the wastewater samples. Degradation of p-chlorophenol was performed with advanced oxidation processes (AOPs, using UV, H2O2/UV, O3/H2O2/UV, O3 and O3/UV. Developed TLC procedure has been found to be simple, rapid and precise. The method was characterized by high sensitivity (limit of detection was 11 ng per band and limit of quantification 35 ng per band, linear range (from 75 to 500 ng per band, r = 0.9965, and high precision, accuracy (mean percentage recovery 98.6%, and specificity. Additionally, the efficiency of degradation was monitored using HPLC giving comparable results with RP TLC measurements. [Acknowledgement. This work was performed within the framework of the research project No. 172017 supported by the Ministry of Education and Science of Serbia.

  19. 热活化过硫酸盐降解水中的2-氯苯酚%Degradation of o-chlorophenol by heat activated persulfate

    Institute of Scientific and Technical Information of China (English)

    刘国强; 王斌楠; 廖云燕; 邵娟; 武瑾玮; 孔德洋; 陆隽鹤

    2014-01-01

    Degradation of o-chlorophenol by sulfate radicals generated by heat activation of persulfate was investigated. This research focused on the influence of temperature, pH, humic acid (HA), inorganic ions to the degradation efficiency. The results indicated that the high temperature and persulfate concerntration promoted the degradation of o-chlorophenol. Degradation of o-chlorophenol exhibited a second-order kinetics and the activation energy was 4. 32 kJ·mol-1 . Acidic condition is more beneficial for the o-chlorophenol degradation than alkaline condition. Both HA and CO2-3 inhibited the o-chlorophenol degradation. Cl- also inhibited the reaction at acidic and neutral conditions. However, at basic condition, such inhibition was not significant. It was presumed that o-chlorophenol was eventually mineralized. However, chlorophenol dimers as intermediates were detected during this process.%利用加入活化K2 S2 O8产生的硫酸根自由基( SO-4·)降解水中2-氯苯酚( o-chlorophenol),探讨了温度、pH、腐殖酸( HA)、无机离子对2-氯苯酚降解的影响.结果表明,增加溶液中过硫酸盐的浓度或提高溶液反应温度,可促进2-氯苯酚的降解,而且2-氯苯酚的降解符合准一级反应动力学规律,其反应表观活化能为4.32 kJ·mol-1.酸性条件下2-氯苯酚的降解效果明显好于碱性条件.2-氯苯酚的降解受到Cl-、CO2-3和腐殖酸的影响.其中,腐殖酸和CO2-3都对反应有明显的抑制作用.Cl-在酸性和中性条件下也会抑制2-氯苯酚降解,但在碱性条件对反应影响不大.2-氯苯酚在SO-4·的作用下会最终降解为乙酸等小分子有机物并最终矿化,有时会伴随有中间产物二聚物的生成.

  20. Influence of supports on photocatalytic degradation of phenol and 4-chlorophenol in aqueous suspensions of titanium dioxide

    Institute of Scientific and Technical Information of China (English)

    Kashif Naeem; Feng Ouyang

    2013-01-01

    The photocatalytic degradation of phenol and 4-chlorophenol (4-CP) in aqueous suspensions with the use of titanium dioxide (TiO2)under UV irradiation was examined.The effects of different supporting materials mixed physically with TiO2 were studied to achieve maximum degradation efficiency.Among the three supports,namely activated carbon (AC),silica (SiO2) and zeolite (ZSM-5),all exhibited paramount efficiency for degradation of phenol and 4-CP and was better than TiO2 alone.The optimum concentration was found to be 50 mg for all supporting materials.The efficiency order of the three supports was as follows:AC > ZSM-5 > SiO2,respectively.Whilst,the degradation of phenol and 4-CP was improved from 70.6% to 87.6% and 80.6% to 89.7%,respectively,within 120 min photocatalysis in the presence of optimal amount of AC.The degradation was also comparatively enhanced in the presence of cheaper rice husk and the activity was closed to ZSM-5 and lower than AC.

  1. Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol.

    Science.gov (United States)

    Liu, Yong; Liu, Lan; Shan, Jun; Zhang, Jingdong

    2015-06-15

    A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na2SO4 concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96 kJ mol(-1). Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP. PMID:25731146

  2. Development of an energy-saving anaerobic hybrid membrane bioreactors for 2-chlorophenol-contained wastewater treatment.

    Science.gov (United States)

    Wang, Yun-Kun; Pan, Xin-Rong; Sheng, Guo-Ping; Li, Wen-Wei; Shi, Bing-Jing; Yu, Han-Qing

    2015-12-01

    A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater. PMID:24880609

  3. Analysis for chloroanisoles and chlorophenols in cork by stir bar sorptive extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Callejon, R M; Troncoso, A M; Morales, M L

    2007-03-30

    A complete methodology for the determination of chloroanisoles and chlorophenols in cork material is proposed. The determination is accomplished by means of a previous liquid-solid extraction followed by stir bar sorptive extraction (SBSE) coupled to gas chromatography-mass spectrometry (GC-MS). Two different liquid-solid extraction experiments were conducted and eight compounds considered (2,6-dichloroanisole, 2,4-dichloroanisole, 2,4,6-trichloroanisole, 2,4,6-trichlorophenol, 2,3,4,6-tetrachloroanisole, 2,3,4,6-tetrachlorophenol, pentachloroanisole and pentachlorophenol). From the results obtained we can conclude that high volume extraction extending extraction time up to 24h is the best choice if we have to release compounds from the inner surfaces of cork stoppers. Recovery percentages ranged from 51% for pentachloroanisole to 81% for 2,4-dichloroanisole. This method allows the determination of an array of compounds involved in cork taint at very low levels from 1.2ng g(-1) for 2,4,6-tricholoroanisole to 23.03ng g(-1) for 2,3,4,6-tetrachlorophenol. PMID:19071569

  4. Quantitative assessment on the contribution of direct photolysis and radical oxidation in photochemical degradation of 4-chlorophenol and oxytetracycline.

    Science.gov (United States)

    Liu, Yiqing; He, Xuexiang; Fu, Yongsheng; Dionysiou, Dionysios D

    2016-07-01

    In UV-254 nm/H2O2 advanced oxidation process (AOP), the potential degradation pathways for organic pollutants include (1) hydrolysis, (2) direct H2O2 oxidation, (3) UV direct photolysis, and (4) hydroxyl radical (HO(•)) reaction. In this study, the contribution of these pathways was quantitatively assessed in the photochemical destruction of 4-chlorophenol (4-CP), demonstrating pathways (3) and (4) to be predominantly responsible for the removal of 4-CP by UV/H2O2 in 50 mM phosphate buffer solution. Increasing reaction pH could significantly enhance the contribution of direct photolysis in UV/H2O2 process. The contribution of HO(•) oxidation was improved with increasing initial H2O2 concentration probably due to the increased formation of HO(•). Presence of sodium carbonate (Na2CO3) as in UV/H2O2/Na2CO3 system promoted the degradation of 4-CP, with carbonate radical (CO3 (•-)) reaction and direct photolysis identified to be the main contributing pathways. The trends in the contribution of each factor were further evaluated and validated on the degradation of the antibiotic compound oxytetracycline (OTC). This study provides valuable information on the relative importance of different reaction pathways on the photochemical degradation of organic contaminants such as 4-CP and OTC in the presence and absence of a CO3 (•-) precursor. PMID:27055892

  5. High efficiency removal of 2-chlorophenol from drinking water by a hydrogen-based polyvinyl chloride membrane biofilm reactor

    International Nuclear Information System (INIS)

    A continuously stirred hydrogen-based membrane biofilm reactor (MBfR) with polyvinyl chloride (PVC) hollow fiber membrane was investigated for removing 2-chlorophenol (2-CP) from contaminated drinking water. The bioreactor startup was achieved by acclimating the microorganisms from a denitrifying and sulfate-reducing MBfR to the drinking water contaminated by 2-CP. The effects of some major factors, including 2-CP loading, H2 pressure, nitrate loading, and sulfate loading, on the removal of 2-CP by the MBfR were systematically investigated. Although the effluent 2-CP concentration increased with its increasing influent loading, the removing efficiency of 2-CP by the MBfR could be up to 94.7% under a high influent loading (25.71 mg/L d). The removing efficiency of 2-CP by the MBfR could be improved by higher H2 pressure, and lower influent nitrate concentration and sulfate concentration. A high H2 pressure can assure enough available H2 as the electron donor for 2-CP degradation. The competition in the electron donor made nitrate and sulfate inhibit the degradation of 2-CP in the MBfR. The electron flux analyses indicated that the degradation of 2-CP only accounted for a small part of electron flux, and the autohydrogenotrophic bacteria in the MBfR were highly efficient for the 2-CP removal.

  6. Development of an energy-saving anaerobic hybrid membrane bioreactors for 2-chlorophenol-contained wastewater treatment.

    Science.gov (United States)

    Wang, Yun-Kun; Pan, Xin-Rong; Sheng, Guo-Ping; Li, Wen-Wei; Shi, Bing-Jing; Yu, Han-Qing

    2015-12-01

    A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater.

  7. Adsorption of ciprofloxacin, bisphenol and 2-chlorophenol on electrospun carbon nanofibers: in comparison with powder activated carbon.

    Science.gov (United States)

    Li, Xiaona; Chen, Shuo; Fan, Xinfei; Quan, Xie; Tan, Feng; Zhang, Yaobin; Gao, Jinsuo

    2015-06-01

    Carbon nanofibers (CNFs) were prepared by electrospun polyacrylonitrile (PAN) polymer solutions followed by thermal treatment. For the first time, the influence of stabilization procedure on the structure properties of CNFs was explored to improve the adsorption capacity of CNFs towards the environmental pollutants from aqueous solution. The adsorption of three organic chemicals including ciprofloxacin (CIP), bisphenol (BPA) and 2-chlorophenol (2-CP) on electrospun CNFs with high surface area of 2326m(2)/g and micro/mesoporous structure characteristics were investigated. The adsorption affinities were compared with that of the commercial powder activated carbon (PAC). The adsorption kinetics and isotherms showed that the maximum adsorption capacities (qm) of CNFs towards the three pollutants are sequenced in the order of CIP>BPA>2-CP, which are 2.6-fold (CIP), 1.6-fold (BPA) and 1.1-fold (2-CP) increase respectively in comparison with that of PAC adsorption. It was assumed that the micro/mesoporous structure of CNFs, molecular size of the pollutants and the π electron interaction play important roles on the high adsorption capacity exhibited by CNFs. In addition, electrostatic interaction and hydrophobic interaction also contribute to the adsorption of CNFs. This study demonstrates that the electrospun CNFs are promising adsorbents for the removal of pollutants from aqueous solutions.

  8. Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol.

    Science.gov (United States)

    Liu, Yong; Liu, Lan; Shan, Jun; Zhang, Jingdong

    2015-06-15

    A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na2SO4 concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96 kJ mol(-1). Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP.

  9. A sensitive and selective spectrophotometric method for 2-chlorophenol based on solid phase extraction with mixed hemimicelle magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Siriboon Mukdasai

    2016-05-01

    Full Text Available The first study of a sensitive and selective spectrophotometric detection of 2-chlorophenol (2-CP was reported. The method is based on derivatization of 2-CP with 4-aminoantipyrine (4-AAP and subsequent preconcentration by solid phase extraction (SPE using mixed hemimicelles adsorbent of cetyltrimethylammonium bromide coated magnetic nanoparticles (CTAB coated Fe3O4 NPs before its detection by spectrophotometry at 510 nm. The adsorption capacity was evaluated using the Langmuir adsorption isotherm model, with high correlation coefficients (R2 = 0.9983. The optimum conditions for SPE were CTAB coated Fe3O4 NPs 20 mg under vortex 60 s and methanol as the desorption solvent under sonication for 7 min. The linearity of the method was in the range of 0.05–1.0 mg L−1 with correlation coefficient (0.9970. The limit of detection (LOD and limit of quantitation (LOQ were 0.01 mg L−1 and 0.05 mg L−1, respectively. Good precision with relative standard deviation (%RSD, n = 5 less than 3.7% was obtained. The method was successfully applied for the determination of 2-CP in soil samples with satisfactory recoveries (81.7–95.2%.

  10. High efficiency removal of 2-chlorophenol from drinking water by a hydrogen-based polyvinyl chloride membrane biofilm reactor.

    Science.gov (United States)

    Xia, Siqing; Zhang, Zhiqiang; Zhong, Fohua; Zhang, Jiao

    2011-02-28

    A continuously stirred hydrogen-based membrane biofilm reactor (MBfR) with polyvinyl chloride (PVC) hollow fiber membrane was investigated for removing 2-chlorophenol (2-CP) from contaminated drinking water. The bioreactor startup was achieved by acclimating the microorganisms from a denitrifying and sulfate-reducing MBfR to the drinking water contaminated by 2-CP. The effects of some major factors, including 2-CP loading, H(2) pressure, nitrate loading, and sulfate loading, on the removal of 2-CP by the MBfR were systematically investigated. Although the effluent 2-CP concentration increased with its increasing influent loading, the removing efficiency of 2-CP by the MBfR could be up to 94.7% under a high influent loading (25.71 mg/L d). The removing efficiency of 2-CP by the MBfR could be improved by higher H(2) pressure, and lower influent nitrate concentration and sulfate concentration. A high H(2) pressure can assure enough available H(2) as the electron donor for 2-CP degradation. The competition in the electron donor made nitrate and sulfate inhibit the degradation of 2-CP in the MBfR. The electron flux analyses indicated that the degradation of 2-CP only accounted for a small part of electron flux, and the autohydrogenotrophic bacteria in the MBfR were highly efficient for the 2-CP removal.

  11. 1H-MAS-NMR Chemical Shifts in Hydrogen-Bonded Complexes of Chlorophenols (Pentachlorophenol, 2,4,6-Trichlorophenol, 2,6-Dichlorophenol, 3,5-Dichlorophenol, and p-Chlorophenol) and Amine, and H/D Isotope Effects on 1H-MAS-NMR Spectra

    OpenAIRE

    Hisashi Honda

    2013-01-01

    Chemical shifts (CS) of the 1H nucleus in N···H···O type hydrogen bonds (H-bond) were observed in some complexes between chlorophenols [pentachlorophenol (PCP), 2,4,6-tricholorophenol (TCP), 2,6-dichlorophenol (26DCP), 3,5-dichlorophenol (35DCP), and p-chlorophenol (pCP)] and nitrogen-base (N-Base) by solid-state high-resolution 1H-NMR with the magic-angle-spinning (MAS) method. Employing N-Bases with a wide range of pKa values (0.65–10.75), 1H-MAS-NMR CS values of bridging H atoms in H-bonds...

  12. 2-氯酚在超临界水-NaOH体系中的脱氯特性%Dechlorination characteristics of o-chlorophenol in supercritical water-sodium hydroxide system

    Institute of Scientific and Technical Information of China (English)

    孙治荣; 马林; 韩延波

    2012-01-01

    The dechlorination characteristics of o-chlorophenol in supercritical water-sodium hydroxide system were studied.The conversion of o-chlorophenol,the yield of chloride ion and the dechlorination selectivity were investigated in the presence of sodium hydroxide.Results indicated that sodium hydroxide could significantly improve the conversion of o-chlorophenol,the yield of chloride ion and the dechlorination selectivity.The conversion of o-chlorophenol was improved with the increase of the additive amount of sodium hydroxide.o-chlorophenol conversed completely at residence time of 27 s under the conditions of 460 ℃,25 MPa,and the molar ratio of sodium hydroxide to o-chlorophenol of 1 to 1.%研究了2-氯酚在超临界水-NaOH体系中的脱氯特性,考察了NaOH添加对2-氯酚转化率、Cl-生成率、脱氯选择性等的影响。实验结果表明,NaOH的添加能够显著提高2-氯酚的转化率、Cl-的生成率和脱氯选择性。2-氯酚的转化率随着NaOH添加量的增大而增大,460℃、25 MPa条件下,NaOH添加量与2-氯酚的摩尔比为1∶1时,停留时间27 s时可实现2-氯酚的完全转化。

  13. Direct determination of chlorophenols in water samples through ultrasound-assisted hollow fiber liquid-liquid-liquid microextraction on-line coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Chao, Yu-Ying; Tu, Yi-Ming; Jian, Zhi-Xuan; Wang, Hsaio-Wen; Huang, Yeou-Lih

    2013-01-01

    In this study we on-line coupled hollow fiber liquid-liquid-liquid microextraction (HF-LLLME), assisted by an ultrasonic probe, with high-performance liquid chromatography (HPLC). In this approach, the target analytes - 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 2,6-dichlorophenol (2,6-DCP), and 3,4-dichlorophenol (3,4-DCP) - were extracted into a hollow fiber (HF) supported liquid membrane (SLM) and then back-extracted into the acceptor solution in the lumen of the HF. Next, the acceptor solution was withdrawn on-line into the HPLC sample loop connected to the HF and then injected directly into the HPLC system for analysis. We found that the chlorophenols (CPs) could diffuse quickly through two sequential extraction interfaces - the donor phase - SLM and the SLM - acceptor phase - under the assistance of an ultrasonic probe. Ultrasonication provided effective mixing of the extracted boundary layers with the bulk of the sample and it increased the driving forces for mass transfer, thereby enhancing the extraction kinetics and leading to rapid enrichment of the target analytes. We studied the effects of various parameters on the extraction efficiency, viz. the nature of the SLM and acceptor phase, the compositions of the donor and acceptor phases, the fiber length, the stirring rate, the ion strength, the sample temperature, the sonication conditions, and the perfusion flow rate. This on-line extraction method exhibited linearity (r(2)≥0.998), sensitivity (limits of detection: 0.03-0.05 μg L(-1)), and precision (RSD%≤4.8), allowing the sensitive, simple, and rapid determination of CPs in aqueous solutions and water samples with a sampling time of just 2 min. PMID:23237709

  14. Novel polyamide-based nanofibers prepared by electrospinning technique for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, Habib, E-mail: bagheri@sharif.edu [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of); Aghakhani, Ali; Baghernejad, Masoud; Akbarinejad, Alireza [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

    2012-02-24

    A novel solid phase microextraction (SPME) fiber was fabricated by electrospinning method in which a polymeric solution was converted to nanofibers using high voltages. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three dimensional structure. Polyamide (nylon 6), due to its suitable characteristics was used to prepare the unbreakable SPME nanofiber. The scanning electron microscopy (SEM) images of this new coating showed a diameter range of 100-200 nm for polyamide nanofibers with a homogeneous and porous surface structure. The extraction efficiency of new coating was investigated for headspace solid-phase microextraction (HS-SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Effect of different parameters influencing the extraction efficiency including extraction temperature, extraction time, ionic strength and polyamide amount were investigated and optimized. In order to improve the chromatographic behavior of phenolic compounds, all the analytes were derivatized prior to the extraction process using basic acetic anhydride. The detection limits of the method under optimized conditions were in the range of 2-10 ng L{sup -1}. The relative standard deviations (RSD) (n = 3) at the concentration level of 1.7-6.7 ng mL{sup -1} were obtained between 1 and 7.4%. The calibration curves of chlorophenols showed linearity in the range of 27-1330 ng L{sup -1} for phenol and monochlorophenols and 7-1000 ng L{sup -1} for dichloro and trichlorophenols. Also, the proposed method was successfully applied to the extraction of phenol and chlorophenols from real water samples and relative recoveries were between 84 and 98% for all the selected analytes except for 2,4,6 tricholophenol which was between 72 and 74%.

  15. Aqueous hydrodechlorination of 4-chlorophenol over an Rh/reduced graphene oxide synthesized by a facile one-pot solvothermal process under mild conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yanlin [Chemical Synthesis and Pollution Control, Key Laboratory of Sichuan Province, College of Chemistry and Chemical Industry, China West Normal University, Nanchong 637002 (China); Fan, Guangyin, E-mail: fanguangyin@cwnu.edu.cn [Chemical Synthesis and Pollution Control, Key Laboratory of Sichuan Province, College of Chemistry and Chemical Industry, China West Normal University, Nanchong 637002 (China); Wang, Chenyu [Department of Chemistry, State University of New York at Binghamton, Binghamton, NY 13902 (United States)

    2014-06-01

    Graphical abstract: The Rh nanoparticles/reduced graphene oxide (Rh NPs/RGO) nanocatalyst synthesized by a solvothermal technique showed high activity and stability for the hydrodechlorination of 4-chlorophenol under mild conditions. - Highlights: • Rh/RGO was synthesized through a one-pot polyol reduction of GO and RhCl{sub 3}. • Complete HDC of 4-chlorophenol was obtained in aqueous phase without any additive. • The Rh/RGO exhibited an excellent catalytic performance for HDC reaction. - Abstract: Reduced graphene oxide (RGO) supported rhodium nanoparticles (Rh-NPs/RGO) was synthesized through one-pot polyol co-reduction of graphene oxide (GO) and rhodium chloride. The catalytic property of Rh-NPs/RGO was investigated for the aqueous phase hydrodechlorination (HDC) of 4-chlorophenol (4-CP). A complete conversion of 4-CP into high valued products of cyclohexanone (selectivity: 23.2%) and cyclohexanol (selectivity: 76.8%) was successfully achieved at 303 K and balloon hydrogen pressure in a short reaction time of 50 min when 1.5 g/L of 4-CP was introduced. By comparing with Rh-NPs deposited on the other supports, Rh-NPs/RGO delivered the highest initial rate (111.4 mmol/g{sub Rh} min) for 4-CP HDC reaction under the identical conditions. The substantial catalytic activity of Rh-NPs/RGO can be ascribed to the small and uniform particle size of Rh (average particle size was 1.7 ± 0.14 nm) on the surface of the RGO sheets and an electron-deficient state of Rh in the catalyst as a result of the strong interaction between the active sites and the surface function groups of RGO.

  16. Excited state dipole moments of chloroanilines and chlorophenols from solvatochromic shifts in electronic absorption spectra: Support for the concept of excited state group moments

    Science.gov (United States)

    Prabhumirashi, L. S.; Satpute, R. S.

    The dipole moments of isomeric o-, m- and p-chloroanilines and chlorophenols in electronically excited L a and L b states are estimated from solvent induced polarization shifts in electronic absorption spectra. It is observed that μ e( L a) > μ e( L b) > μ g, which is consistent with the general theory of polarization red shift. The μ es are found to be approximately co-linear with the corresponding μ gs. The concept of group moments is extended to aromatic molecules in excited states. This approach is found to be useful in understanding correlations among the excited states of mono- and disubstituted benzenes.

  17. Characterization of a Second tfd Gene Cluster for Chlorophenol and Chlorocatechol Metabolism on Plasmid pJP4 in Ralstonia eutropha JMP134(pJP4)

    OpenAIRE

    Laemmli, Caroline M.; Leveau, Johan H. J.; Zehnder, Alexander J. B.; van der Meer, Jan Roelof

    2000-01-01

    Within the 5.9-kb DNA region between the tfdR and tfdK genes on the 2,4-dichlorophenoxyacetic acid (2,4-D) catabolic plasmid pJP4 from Ralstonia eutropha JMP134, we identified five open reading frames (ORFs) with significant homology to the genes for chlorocatechol and chlorophenol metabolism (tfdCDEF and tfdB) already present elsewhere on pJP4. The five ORFs were organized and assigned as follows: tfdDIICIIEIIFII and tfdBII (in short, the tfdII cluster), by analogy to tfdCDEF and tfdB (the t...

  18. A new method of chlorophenols decomposition based on UV-irradiation by XeBr-excilamp and their subsequent biodegradation

    Science.gov (United States)

    Sosnin, E. A.; Matafonova, G. G.; Batoev, V. B.; Christofi, N.

    2008-01-01

    The combined decomposition method of chlorophenols (CP) is offered. The method is based on photolysis of CP through XeBr-excilamp UV irradiation at 283 nm in a flow photoreactor with subsequent treatment of photolysis products by microorganism-destructor B. cereus isolated from an aeration pond of Baikal pulp-and-paper mill. At initial concentration of CP of 20 mg/l the polluted solutions can be utilized directly by means of biological treatment using B. cereus under aerobic conditions. However, if the initial CP concentration is higher than 20 mg/l, the polluted solutions are low biodegradable. It is shown, that the combined treatment is most effective method in this case. At initial CP concentration of 50 mg/l and higher it is suggested to use the deep preliminary UV-treatment with the purpose of removal 80-90 % of initial CP. It is revealed, that 4-CP is relatively persistent compound for B. cereus, easily decomposed by UV-radiation of XeBr-excilamp. As a result of subsequent biological treatment during 10 days the utilization of basic CP photoproducts is obtained. Experimentally, the preliminary UV-processing time was essentially less than that found earlier by E. Tamer, Z. Hamid, Aly A. (Chemosphere, 2006), where the half-life periods of initial CP were from 2.2 to 54 hours at the same value of initial concentration of CP. Correspondingly, the total CP decomposition process was accompanied by high power inputs. It is suggested to use mentioned above method for effective CP decomposition at high concentration values.

  19. Assessment of PCDD/Fs formation in the Fenton oxidation of 2-chlorophenol: Influence of the iron dose applied.

    Science.gov (United States)

    Vallejo, Marta; Fernández-Castro, Pablo; San Román, M Fresnedo; Ortiz, Inmaculada

    2015-10-01

    Toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may be formed during remediation of chlorinated phenols via Fenton oxidation. To highlight the need for monitoring the production of toxic byproducts in these reactions, this work assessed the influence of iron dose (0.09-0.36 mM) on the Fenton oxidation of 2-chlorophenol (2-CP, 15.56 mM), a potential precursor of PCDD/Fs, by quantifying 2-CP removal and mineralization rates as well as byproducts yields, including PCDD/Fs. Although the increase in the iron dose showed positive contribution to 2-CP oxidation, under the operating conditions of the current study (H2O2 at 20% of the stoichiometric dose and 20 °C), there was no effect on the mineralization rate, and TOC and chlorine balances were far to be closed, depicting the presence of chlorinated organic byproducts in the reaction medium. After 4 h of treatment, the total PCDD/Fs concentrations increased by 14.5-39 times related to the untreated sample when the iron doses tested decreased from 0.36 to 0.09 mM, with preferential formation of PCDFs over PCDDs and dominance of lower chlorinated congeners such as tetra and penta-PCDD/Fs. The treatment with the highest iron dose (0.36 mM) exhibited the lowest PCDD/Fs yields and was thus most successful at mitigating toxic byproducts of the Fenton oxidation, leading to lower sample toxic equivalence (TEQ) value. PMID:26134538

  20. Transformation, products, and pathways of chlorophenols via electro-enzymatic catalysis: How to control toxic intermediate products.

    Science.gov (United States)

    Du, Penghui; Zhao, He; Li, Haitao; Zhang, Di; Huang, Ching-Hua; Deng, Manfeng; Liu, Chenming; Cao, Hongbin

    2016-02-01

    Chlorophenols can be easily oxidized into chlorobenzoquinones (CBQs), which are highly toxic and have been linked to bladder cancer risk. Herein, we report the transformation, products, and pathways of 2,4-dichlorophenol (DCP) by horseradish peroxidase (HRP) and electro-generated hydrogen peroxide (H2O2) and suggest methods to control the formation of toxic intermediate products. After a 10-min electroenzymatic process, 99.7% DCP removal may be achieved under optimal conditions. A total of 16 reaction products, most of which are subsequently verified as DCP polymers and related quinone derivatives, are identified by using ultra-performance liquid chromatography-time-of-flight mass spectrometry (UPLC-TOF-MS). A five-step reaction pathway for DCP transformation, including HRP-driven substrate oxidation, substitution and radical coupling, quick redox equilibrium, nucleophilic reaction and precipitation from aqueous solution, is proposed. Current variations and the presence of CO2 could significantly affect these reaction pathways. In particular, higher currents enhance the hydroxylation process by promoting alkaline conditions and abundant H2O2 formation. As both OH(-) and H2O2 are strong nucleophiles, they easily react with CBQ products to form hydroxylated products, which can significantly reduce solution toxicity. An adequate supply of CO2 can provide favorable pH conditions and facilitate enzymatic steps, such as substrate oxidation and radical coupling, to generate precipitable polymerized products. All of the results suggest that toxic intermediate products can be effectively reduced and controlled during the electro-enzymatic process to remove DCP and other phenolic pollutants from wastewaters. PMID:26519798

  1. Sorption and degradation of chlorophenols, nitrophenols and organophosphorus pesticides in the subsoil under landfills — laboratory studies

    Science.gov (United States)

    Kjeldsen, Peter; Kjølholt, Jesper; Schultz, Birgit; Christensen, Thomas H.; Tjell, Jens Christian

    1990-09-01

    Landfills and old industrial plant sites have been identified in an increasing number of cases as point sources of groundwater pollution, dissipating a wide range of industrial chemicals and pesticides. To study the fate of co-disposed chemicals in the subsoil of landfills, anaerobic soil columns loaded with anaerobic leachate from a municipal landfill were set up. The leachate was spiked with eleven compounds representing three groups of chemicals: chlorophenols, nitrophenols and organophosphates. Two subsoils were used in the study. The columns were maintained at Danish groundwater temperature (8-10°C), and were run for a period of 10 months. Analysis of the influent leachate concentrations of the spiked compounds showed that the concentrations were constant during the entire experimental period. Many of the compounds showed delayed breakthrough (compared to chloride breakthrough) in both soils, followed by a constant effluent concentration ratio of less than unity indicating that degradation was occuring. The velocities for the chloro- and nitrophenols were in the range of 10-100% of the water velocity in the two subsoils. The distribution coefficient for the specific phenol, the acidity and the pH of the soil apparently governed the retardation of the phenolic compounds. Degradation of most of the phenols was observed with half-like values of 30-150 days. The four organophosphorus pesticides, Dimethoate ®, Malathion ®, Sulfotep ® and Fenitrothion ®, showed relative velocities from < 10% to ≈ 100%. Malathion ® and Sulfotep ® were degraded with half-life values of 10-20 days, while Dimethoate ® was not significantly degraded in the two soil columns. Fenitrothion ® did not appear in the effluent from the columns within the experimental period of time, probably due to high retardation.

  2. Application of solid-phase microextraction and gas chromatography-mass spectrometry for the determination of chlorophenols in leather.

    Science.gov (United States)

    de Souza Silveira, Cristine D; Martendal, Edmar; Soldi, Valdir; Carasek, Eduardo

    2012-02-01

    This paper proposes a new analytical procedure based on the headspace solid-phase microextraction (HS-SPME) technique and gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) for the determination of 16 phenols extracted from leather samples. The optimized conditions for the HS-SPME were obtained through two experimental designs - a two-level fractional factorial design followed by a central composite design - using the commercial SPME fiber polyacrylate 85 μm (PA). The best extraction conditions were as follows: 200 μL of derivatizing agent (acetic anhydride), 20 mL of saturated aqueous NaCl solution and extraction time and temperature of 50 min and 75°C, respectively. All optimized conditions were obtained with fixed leather sample mass (250 mg), vial volume (40 mL) and phosphate buffer pH (12) and concentration (50 mmol/L). Detection limits ranging from 0.03 to 0.20 ng/g, and relative standard deviation (RSD) lower than 10.23% (n=6) for a concentration of 800 ng/g (chlorophenols) and 1325 ng/g (2-phenylphenol) in the splitless mode were obtained. The recovery was studied at three concentration levels by adding different amounts of phenols to the leather sample and excellent recoveries ranging from 90.0 to 107.2% were obtained. The validated method was shown to be suitable for the quantification of phenols in leather samples, as it is simple, relatively fast and sensitive.

  3. Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong; Liu, Lan; Shan, Jun; Zhang, Jingdong, E-mail: zhangjd@mail.hust.edu.cn

    2015-06-15

    Highlights: • Pd and reduced graphene oxide are deposited on foam-Ni via electrodeposition. • Pd particles supported on RGO possess large active surface area. • Pd/RGO/foam-Ni shows high electrocatalytic activity for dechlorination of 4-CP. • 100% 4-CP can be removed on Pd/RGO/foam-Ni under optimum ECH conditions. - Abstract: A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na{sub 2}SO{sub 4} concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96 kJ mol{sup −1}. Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP.

  4. Solar photocatalytic degradation of chlorophenols mixture (4-CP and 2,4-DCP): Mechanism and kinetic modelling.

    Science.gov (United States)

    Abeish, Abdulbasit M; Ang, Ha Ming; Znad, Hussein

    2015-01-01

    The solar-photocatalytic degradation mechanisms and kinetics of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) using TiO2 have been investigated both individually and combined. The individual solar-photocatalytic degradation of both phenolic compounds showed that the reaction rates follow pseudo-first-order reaction. During the individual photocatalytic degradation of both 4-CP and 2,4-DCP under the same condition of TiO2 (0.5 g L(-1)) and light intensities (1000 mW cm(-2)) different intermediates were detected, three compounds associated with 4-CP (hydroquinone (HQ), phenol (Ph) and 4-chlorocatechol (4-cCat)) and two compounds associated with 2,4-DCP (4-CP and Ph). The photocatalytic degradation of the combined mixture (4-CP and 2,4-DCP) was also investigated at the same conditions and different 2,4-DCP initial concentrations. The results showed that the degradation rate of 4-CP decreases when the 2,4-DCP concentration increases. Furthermore, the intermediates detected were similar to that found in the individual degradation but with high Ph concentration. Therefore, a possible reaction mechanism for degradation of this combined mixture was proposed. Moreover, a modified Langmuir-Hinshelwood (L-H) kinetic model considering all detected intermediates was developed. A good agreement between experimental and estimated results was achieved. This model can be useful for scaling-up purposes more accurately as its considering the intermediates formed, which has a significant effect on degrading the main pollutants (4-CP and 2,4-DCP).

  5. Effect of process variables interaction on simultaneous adsorption of phenol and 4-chlorophenol: statistical modeling and optimization using RSM

    Science.gov (United States)

    Leong, Kwok-Yii; See, Sylvia; Lim, Jun-Wei; Bashir, Mohammed J. K.; Ng, Choon-Aun; Tham, Leony

    2016-02-01

    Results of the interaction of process variables and the consequential mixture of phenolic compounds adsorption study are expected to shed brighter light on the wastewater treatment applications. Accordingly, the aims of this research are to model and optimize the process variables which impinged on the simultaneous adsorption of phenol and 4-chlorophenol (4-CP) in the binary solution by spherical activated carbon (SAC). Batch assessments were designed using response surface methodology software. The process variables, namely SAC dosage and pH were varied over the 1.50-3.50 g/L and 4.00-9.00 g/L ranges, respectively, were experimented. The analysis of variance results showed the significant models could precisely predict the percentage removals of phenol and 4-CP, indicating models reliability. The interaction of process variables was inconspicuous for the case of phenol adsorption. However, increasing the pH would deteriorate the 4-CP adsorption which was partially offset by raising the SAC dosage. Considering the environmental benefits, optimization taken place at the SAC dosage and pH of 3.50 g/L and 7.60 g/L, respectively, was selected. By employing the optimized conditions of SAC dosage of 3.50 g/L at pH 7.60 for the adsorption process, the predicted phenol and 4-CP removal percentages were found to be 85.4 % (73.1 mg/g) and 96.2 % (82.6 mg/g), respectively, which were in agreement with the experimental runs.

  6. A new combined green method for 2-Chlorophenol removal using cross-linked Brassica rapa peroxidase in silicone oil.

    Science.gov (United States)

    Tandjaoui, Nassima; Abouseoud, Mahmoud; Couvert, Annabelle; Amrane, Abdeltif; Tassist, Amina

    2016-04-01

    This study proposes a new technique to treat waste air containing 2-Chlorophenol (2-CP), namely an integrated process coupling absorption of the compound in an organic liquid phase and its enzymatic degradation. Silicone oil (47V20) was used as an organic absorbent to allow the volatile organic compound (VOC) transfer from the gas phase to the liquid phase followed by its degradation by means of Cross-linked Brassica rapa peroxidase (BRP) contained in the organic phase. An evaluation of silicone oil (47V20) absorption capacity towards 2-CP was first accomplished by determining its partition coefficient (H) in this solvent. The air-oil partition coefficient of 2-CP was found equal to 0.136 Pa m(3) mol(-1), which is five times lower than the air-water value (0.619 Pam(3) mol(-1)). The absorbed 2-CP was then subject to enzymatic degradation by cross-linked BRP aggregates (BRP-CLEAs). The degradation step was affected by four parameters (contact time; 2-CP, hydrogen peroxide and enzyme concentrations), which were optimized in order to obtain the highest conversion yield. A maximal conversion yield of 69% and a rate of 1.58 mg L(-1) min(-1)were obtained for 100 min duration time when 2-CP and hydrogen peroxide concentrations were respectively 80 mg L(-1) and 6 mM in the presence of 2.66 UI mL(-1) BRP-CLEAs. The reusability of BRP-CLEAs in silicone oil was assessed, showing promising results since 59% of their initial efficiency remained after three batches. PMID:26802263

  7. Caracterización del proceso de adsorción de 3-cloro fenol desde solución acuosa sobre carbon activado por calorimetria de inmersión Characterization of 3-chlorophenol adsorption process from aqueous solution on activated carbon by immersion calorimetry

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2009-01-01

    Full Text Available The immersion enthalpy of activated carbon in 3-chlorophenol solutions, of 100 mg L-1, is determined at different pH values between 3 and 11 with results between 37.6 and 21.2 J g-1. The 3-chlorophenol adsorbed quantities on the activated carbon during the calorimetric experience, are between 1.13 and 2.19 mg g-1, for different pH values of the solution. The 3-chlorophenol adsorbed quantity and the immersion enthalpy decrease by increasing of the pH solution, while increasing the adsorbed quantity increases the immersion enthalpy value.

  8. Chlorophenol's ultra-trace analysis in environmental samples by chitosan-zinc oxide nanorod composite as a novel coating for solid phase micro-extraction combined with high performance liquid chromatography.

    Science.gov (United States)

    Alizadeh, Reza

    2016-01-01

    In this study, a simple, novel, and efficient preconcentration method has been developed for the determination of some chlorophenols (4-chlorophenol, 2,5-dichlorophenol, 2,3-dichlorophenol, and 2,4,6-trichlorophenol) using a direct solid phase microextraction (D-SPME) based on chitosan-ZnO nanorod composite combined with high performance liquid chromatography (HPLC). A one step-novel hydrothermal method was demonstrated on the fabrication of ZnO nanorods arrayed on the fused silica fiber in the chitosan hydrogel solution (CZNC) as a new coating of SPME fiber. The coating was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) instruments. The CZNC coating has combined the merits of both ZnO nanorods and chitosan hydrogel; it has several improvements such as increased extraction efficiency of chlorophenols and longer life time (over 80 cycles of D-SPME-HPLC operation). Experimental design method was used for optimization of extraction conditions and determination of four chlorophenols in water samples by SPME-HPLC-UV method. The calibration curves were linear from 5 to 1000 µg L(-1) for analytes, and the limits of detection were between 0.1 and 2 µg L(-1). Single fiber repeatability and fiber-to-fiber reproducibility were in the range of 5.8-10.2% and 8.8-14.5%, respectively. The spiked recoveries at 50 µg L(-1) for environmental water sample were in the range of 93-102%. PMID:26695336

  9. HIGH PERFORMANCE LIQUID CHROMATOGRAPHY ANALYSIS OF CHLOROPHENOL COMPOUNDS IN THE WATER ENVIRONMENT%水环境中氯酚污染物的高效液相色谱分析

    Institute of Scientific and Technical Information of China (English)

    庄惠生; 王琼娥; 阮国洪

    2003-01-01

    The determination of 2-chlorophenol, 24-dichlorophenol, 2,3,4-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol in the water environment was studied by the high performance liquid chromatography with solid phase extraction in this paper.

  10. Suitability of dispersive liquid-liquid microextraction for the in situ silylation of chlorophenols in water samples before gas chromatography with mass spectrometry.

    Science.gov (United States)

    Saraji, Mohammad; Ghambari, Hoda

    2015-10-01

    Trace analysis of chlorophenols in water was performed by simultaneous silylation and dispersive liquid-liquid microextraction followed by gas chromatography with mass spectrometry. Dispersive liquid-liquid microextraction was carried out using an organic solvent lighter than water (n-hexane). The effect of different silylating reagents on the method efficiency was investigated. The influence of derivatization reagent volume, presence of catalyst and derivatization/extraction time on the yield of the derivatization reaction was studied. Different parameters affecting extraction efficiency such as kind and volume of extraction and disperser solvents, pH of the sample and addition of salt were also investigated and optimized. Under the optimum conditions, the calibration graphs were linear in the range of 0.05-100 ng/mL and the limit of detection was 0.01 ng/mL. The enrichment factors were 242, 351, and 363 for 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, respectively. The values of intra- and inter-day relative standard deviations were in the range of 3.0-6.4 and 6.1-9.9%, respectively. The applicability of the method was investigated by analyzing water and wastewater samples.

  11. Photocatalytic degradation of 4-chlorophenol under P-modified TiO2/UV system: kinetics, intermediates, phytotoxicity and acute toxicity.

    Science.gov (United States)

    Elghniji, Kais; Hentati, Olfa; Mlaik, Najwa; Mahfoudh, Ayman; Ksibi, Mohamed

    2012-01-01

    A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900 degrees C. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5(500) prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500 degrees C had an apparent rate constant equal to 0.0075 min(-1), which is superior to the performance of a commercial photocatalyst Degussa P25 K(app) = 0.0045 min(-1) and of unmodified TiO2 (TP0(500)) K(app) = 0.0022 min(-1). From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone (HQ), benzoquinone (BQ) and (4CC) 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato (Lycopersicon esculentum) whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished. PMID:22655362

  12. Analysis of chlorophenols in environmental water using polydopamine-coated magnetic graphene as an extraction material coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Ye, Qing; Liu, Linhai; Chen, Zongbao; Hong, Liming

    2016-05-01

    In this work, polydopamine-coated magnetic graphene nanocomposites were synthesized by a simple solvothermal reaction and self-polymerization of dopamine, and the as-made nanocomposites were successfully applied as an effective adsorbent for the preconcentration of the four chlorophenols in environmental water samples before high-performance liquid chromatography. The polydopamine-coated magnetic graphene nanocomposites have several advantages such as a high surface area, fast separation ability, super-hydrophilicity, and high peak intensities for aromatic analytes. Various parameters, including eluting solvent and volume, the amounts of absorbents, extraction time and elution time were optimized. Validation experiments showed that the optimized method had good linearity (r(2) > 0.9990), satisfactory precision (RSD < 6.7%) and high recovery (90-105%). The limits of detection were 0.013-0.020 μg/L and the limits of quantification ranged from 0.043 to 0.070 μg/L. The results indicated that the proposed method had advantages of convenience, good sensitivity, and high efficiency. The method has been applied successfully to analyze chlorophenols in real water samples. PMID:26923910

  13. Suitability of dispersive liquid-liquid microextraction for the in situ silylation of chlorophenols in water samples before gas chromatography with mass spectrometry.

    Science.gov (United States)

    Saraji, Mohammad; Ghambari, Hoda

    2015-10-01

    Trace analysis of chlorophenols in water was performed by simultaneous silylation and dispersive liquid-liquid microextraction followed by gas chromatography with mass spectrometry. Dispersive liquid-liquid microextraction was carried out using an organic solvent lighter than water (n-hexane). The effect of different silylating reagents on the method efficiency was investigated. The influence of derivatization reagent volume, presence of catalyst and derivatization/extraction time on the yield of the derivatization reaction was studied. Different parameters affecting extraction efficiency such as kind and volume of extraction and disperser solvents, pH of the sample and addition of salt were also investigated and optimized. Under the optimum conditions, the calibration graphs were linear in the range of 0.05-100 ng/mL and the limit of detection was 0.01 ng/mL. The enrichment factors were 242, 351, and 363 for 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, respectively. The values of intra- and inter-day relative standard deviations were in the range of 3.0-6.4 and 6.1-9.9%, respectively. The applicability of the method was investigated by analyzing water and wastewater samples. PMID:26257251

  14. Development of solid-phase extraction and solid-phase microextraction methods for the determination of chlorophenols in cork macerate and wine samples.

    Science.gov (United States)

    Insa, S; Salvadó, V; Anticó, E

    2004-08-20

    Tri-, tetra- and pentachlorophenol (TCP, TeCP and PCP) can be considered the precursors in the formation of corresponding chloroanisoles, known to be powerful odorants in corks and wine. Determining the presence of these chlorophenolic compounds in cork soaking solutions (ethanol/water mixtures, 12% (v/v) ethanol used for cork quality control testing), or in wine can be achieved by acetylation/gas chromatography electron-capture detection. In order to reach the required sensitivity, a previous preconcentration step is necessary. Solid-phase extraction (SPE) and headspace solid-phase microextraction (HS-SPME) have given good results for the preconcentration of TCP, TeCP and PCP in such matrices. The use of Oasis HLB cartridges gives acceptable recoveries for the three compounds when different volumes (50-250 mL) of cork macerate with concentrations ranging from 20 to 150 ng/L are processed. Preconcentration based on HS-SPME has also been optimised with a 100 microm polydimethylsiloxane fibre and in situ derivatization. The HS-SPME method allows chlorophenols in a cork soaking solution and in wine to be determined with a limit of detection of 1 ng/L for each compound (in cork macerate) and a repeatability of around 0.5%-5% (n=8) for a concentration level of 30 ng/L. PMID:15481456

  15. Photocatalytic degradation of 4-chlorophenol under P-modified TiO2/UV system: Kinetics, intermediates, phytotoxicity and acute toxicity

    Institute of Scientific and Technical Information of China (English)

    Kais Elghniji; Olfa Hentati; Najwa Mlaik; Ayman Mahfoudh; Mohamed Ksibi

    2012-01-01

    A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route.The effects of phosphorus content and calcination temperature on the crystalline structure,grain growth,surface area,and the photocatalytic activity of P-modified TiO2 were investigated.The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900℃.Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500℃ had an apparent rate constant equal to 0.0075 min-1,which is superior to the performance of a commercial photocatalyst Degussa P25 Kapp =0.0045 min-1 and of unmodified TiO2(TP(0)500)Kapp =0.0022 min-1.From HPLC analyses,various hydroxylated intermediates formed during oxidation had been identified,including hydroquinone(HQ),benzoquinone(BQ)and(4CC)4-chlorocatechol as main products.Phytotoxicity was assessed before and after irradiation against seed germination of tomato(Lycopersicon esculentum)whereas acute toxicity was assessed by using Folsomia candida as the test organism.Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished.

  16. Influence of Phases Content on Pt/TiO2, Pd/TiO2 Catalysts for Degradation of 4-Chlorophenol at Room Temperature

    Directory of Open Access Journals (Sweden)

    D. S. García-Zaleta

    2016-01-01

    Full Text Available Different Pt/TiO2 and Pd/TiO2 catalysts were prepared by sol-gel method. The influence of different amounts of noble metals (1–5 mol-% present on the microstructure as well as the photocatalytic property under 4-chlorophenol degradation was evaluated. The anatase phase was favored at low Pt content; however, the apparition of new phases after 3 mol-% (PtO suggests a saturation lattice considering our solubility limit at 1 mol-%. Similar trend was observed when Pd was added to the TiO2 lattice. The as-prepared catalysts were deeply characterized by X-ray diffraction (XRD with the Rietveld Method, Raman spectroscopy, high resolution scanning electron microscopy (HRSEM, scanning transmission electron microscopy (STEM, Brunauer-Emmett-Teller (BET adsorption analysis, and X-Ray photoelectron spectroscopy (XPS. Unit-cell parameter of TiO2 phases varied from 30 to 93 vol-% depending on the amount of Pt or Pd added to the composite. HRTEM and HRSEM identified the phases in the catalysts and confirmed the nanometric size and morphology of the catalysts. An improvement in removal efficiency of 4-chlorophenol was obtained in all the specimens compared with the commercial Degussa P25, which can be explained in terms of phase composition and modification of the band gap.

  17. Photochemical transformation of anionic 2-nitro-4-chlorophenol in surface waters: laboratory and model assessment of the degradation kinetics, and comparison with field data.

    Science.gov (United States)

    Sur, Babita; De Laurentiis, Elisa; Minella, Marco; Maurino, Valter; Minero, Claudio; Vione, Davide

    2012-06-01

    Anionic 2-nitro-4-chlorophenol (NCP) may occur in surface waters as a nitroderivative of 4-chlorophenol, which is a transformation intermediate of the herbicide dichlorprop. Here we show that NCP would undergo efficient photochemical transformation in environmental waters, mainly by direct photolysis and reaction with OH. NCP has a polychromatic photolysis quantum yield Φ(NCP)=(1.27±0.22)·10(-5), a rate constant with OH k(NCP,)(OH)=(1.09±0.09)·10(10) M(-1) s(-1), a rate constant with (1)O(2)k(NCP,1O2)=(2.15±0.38)·10(7) M(-1) s(-1), a rate constant with the triplet state of anthraquinone-2-sulphonate k(NCP,3AQ2S*)=(5.90±0.43)·10(8) M(-1) s(-1), and is poorly reactive toward CO(3)(-). The k(NCP,3AQ2S*) value is representative of reaction with the triplet states of chromophoric dissolved organic matter. The inclusion of photochemical reactivity data into a model of surface-water photochemistry allowed the NCP transformation kinetics to be predicted as a function of water chemical composition and column depth. Very good agreement between model predictions and field data was obtained for the shallow lagoons of the Rhône delta (Southern France).

  18. 非均相光Fenton降解4-氯酚的研究%Degradation efficiency of 4-chlorophenol via heterogeneous photo-Fenton

    Institute of Scientific and Technical Information of China (English)

    王维明; 张冉; 王树涛; 刘婷; 尤宏

    2013-01-01

    制备了以Al2O3/TiO2为载体的负载型铁氧化物催化剂,对催化剂进行SEM、XRD、UV-vis-DRS和XPS分析,考察H2O2投加量、催化剂投加量、4-氯酚初始质量浓度对4-氯酚处理效果的影响,分析了非均相光Fenton体系的氧化机理.结果表明,所制备的负载型铁氧化物催化剂为α-FeOOH与γ-Fe2O3的混合物,其表面存在较多的颗粒和孔穴,吸附性强,具有很高的催化活性.H2O2、铁氧化物催化剂、紫外灯之间存在协同作用,所构成的非均相光Fenton体系对4-氯酚具有良好的去除效果.其反应机理为表面催化,催化剂表面的Fe(Ⅲ)在光照的作用下被还原为Fe(Ⅱ).在催化剂投加量为1 g/L,H2O2浓度为7.84mmol/L时,对4-氯酚的降解效果达到最佳,反应进行30 min后4-氯酚的去除率大于99%,反应1h矿化度可达91.4%.%This paper aims to introduce our preparation of catalysts loaded on Al2O3/TiO2 and the heterogeneous photo-Fenton reaction system we have established for the study of the degradation efficiency of the 4-chlorophenol. The catalysts we have prepared are characterized by SEM, XRD, by means of which we have investigated the effect of H2O2 dosage, along with the catalyst dosage and initial concentration of the 4-chlorophenol on 4-chlorophenol degradation needed. In addition, we have also done experiments to explore the oxidation mechanism of heterogeneous photo-Fenton system. The results of our research show that the ingredients of iron oxidate catalysts loaded on Al2O3/TiO2 were the mixture of α- FeOOH and γ - Fe2O3; and, as compared with Al2O3/TiO2 carrier, it has been found that there exist more surface particles and cavity on the catalyst surface, whose specific surface area proves to be wider for its adsorption, and, therefore, helps to enhance their catalytic activity. The heterogeneous photo-Fenton system we have established proves to be highly effective for degrading 4-chlorophenol. Furthermore, we have worked out the

  19. Photochemical transformation of anionic 2-nitro-4-chlorophenol in surface waters: Laboratory and model assessment of the degradation kinetics, and comparison with field data

    Energy Technology Data Exchange (ETDEWEB)

    Sur, Babita [Dipartimento di Chimica, Universita di Torino, Via P. Giuria 5, 10125 Torino (Italy); Department of Chemical Engineering, Calcutta University, 92 Acharya P. C. Road, Kolkata 700009 (India); De Laurentiis, Elisa; Minella, Marco; Maurino, Valter; Minero, Claudio [Dipartimento di Chimica, Universita di Torino, Via P. Giuria 5, 10125 Torino (Italy); Vione, Davide [Dipartimento di Chimica, Universita di Torino, Via P. Giuria 5, 10125 Torino (Italy); Centro Interdipartimentale NatRisk, Universita di Torino, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy)

    2012-06-01

    Anionic 2-nitro-4-chlorophenol (NCP) may occur in surface waters as a nitroderivative of 4-chlorophenol, which is a transformation intermediate of the herbicide dichlorprop. Here we show that NCP would undergo efficient photochemical transformation in environmental waters, mainly by direct photolysis and reaction with {center_dot}OH. NCP has a polychromatic photolysis quantum yield {Phi}{sub NCP} = (1.27 {+-} 0.22) {center_dot} 10{sup -5}, a rate constant with {center_dot}OH k{sub NCP,}{center_dot}{sub OH} = (1.09 {+-} 0.09) {center_dot} 10{sup 10} M{sup -1} s{sup -1}, a rate constant with {sup 1}O{sub 2}k{sub NCP,1O2} = (2.15 {+-} 0.38) {center_dot} 10{sup 7} M{sup -1} s{sup -1}, a rate constant with the triplet state of anthraquinone-2-sulphonate k{sub NCP,3AQ2S*} = (5.90 {+-} 0.43) {center_dot} 10{sup 8} M{sup -1} s{sup -1}, and is poorly reactive toward CO{sub 3}{sup -}{center_dot}. The k{sub NCP,3AQ2S*} value is representative of reaction with the triplet states of chromophoric dissolved organic matter. The inclusion of photochemical reactivity data into a model of surface-water photochemistry allowed the NCP transformation kinetics to be predicted as a function of water chemical composition and column depth. Very good agreement between model predictions and field data was obtained for the shallow lagoons of the Rhone delta (Southern France). Highlights: Black-Right-Pointing-Pointer Phototransformation kinetics of 2-nitro-4-chlorophenol, relevant to surface waters. Black-Right-Pointing-Pointer Determination of photochemical reactivity data in the laboratory. Black-Right-Pointing-Pointer Model approach to combine photochemical reactivity with environmental variables. Black-Right-Pointing-Pointer Good agreement with field data in lagoon water (Rhone delta, Southern France). Black-Right-Pointing-Pointer Direct photolysis and reaction with {center_dot}OH as main photoprocesses in the environment.

  20. Study on the Acute and Subacute Toxicities of Chlorophenols on Carassias auratus%氯酚类化合物对金鱼的急性和亚急性毒性研究

    Institute of Scientific and Technical Information of China (English)

    聂晶磊; 刘锋; 周春玉; 刘征涛

    2001-01-01

    研究了2-氯酚、2,6-二氯酚,2,3,4-三氯酚、2,3,5,6-四氯酚、五氯酚5种氯酚类化合物对鲤科金鱼(Carassias auratus)的急性毒性和这5种化合物在1/2 LC50,1/4 LC50,1/6 LC50浓度下对金鱼肝脏中Na+-K+-ATP酶的影响变化。结果显示:①氯酚类化合物随氯原子数目在苯环上的增加,其急性毒性增加;②亚急性毒性指标Na+-K+-ATP酶对氯酚类化合物比较敏感,是一种较好的生物指示物。并讨论了氯酚类化合物对Na+-K+-ATP酶活性产生影响的机制。%The acute and subacute toxicities of five chlorophenols,i.e.2-chlorophenol,2,6-dichlorophenol,2,3,4-trichlorophenol,2,3,5,6-tetrachlorophenol and pentachlorophenol on the Carassias auratus were studied in vivo.The subacute toxicity endpoints were Carassias auratus liver's Na+-K+-ATPase activity under 1/2 LC50,1/4 LC50,1/6 LC50 of five chlorophenols.The results showed that:①The acute toxicity LC50 of chlorophenols increased with the number of chlorine atom on the benzene ring.②Na+-K+-ATPase activity is sensitive to the chlorophenols,thus being a good biomarker for the chlorophenols pollution.The mechanism of the phenomena related to Na+-K+-ATPase activity decrease in fish liver was discussed.

  1. 4-氯酚对厌氧颗粒污泥产甲烷活性的影响%Influence of 4-chlorophenol on activity of methane-producing microorganisms in anaerobic granular sludge

    Institute of Scientific and Technical Information of China (English)

    罗艳; 何仕均; 王建龙; 解明曙

    2012-01-01

    With anaerobic granular sludge from an anaerobic baffled reactor(ABR) as the research object and glucose as the co-substrate, the influence of 4-chlorophenol concentration on the methane-producing microorganisms in anaerobic granular sludge was investigated. The test results showed that: 4-chlorophenol had a strong inhibition effect on the activity of methane-producing microorganisms in anaerobic granular sludge, the slightest degree of inhibition appeared when the mass concentration of 4-chlorophenol was 300 mg/L; and then, with the continuous increase of the 4-chlorophenol concentration, the methane-producing activity of anaerobic granular sludge decreased obviously; when it increased to 400, 500 and 600 mg/L, the inhibition rate were 31%, 68% and 54% respectively. The inhibition effect of 4-chlorophenol on the anaerobic biological degradation of glucose happened in the later stage of the reaction when the concentration was low, and in the early stage of the reaction when the concentration was high. In the recovery test carried out simultaneously, the inhibition effect of 4-chlorophenol with different concentrations on the production of methane was still exist; however, the inhibition degree was decreased.%利用取自ABR反应器的厌氧颗粒污泥,以葡萄糖为共基质,测定了不同浓度4-氯酚对厌氧污泥产甲烷微生物的影响以及活性恢复情况.试验结果表明:4-氯酚对厌氧颗粒污泥产甲烷活性具有较强的抑制作用,当4-氯酚的质量浓度为300 mg/L时,抑制作用最小;并且随着4-氯酚浓度的继续提高,厌氧颗粒污泥的产甲烷活性显著下降.当4-氯酚的质量浓度为400、500、600 mg/L时,相应的抑制程度为31%、68%、54%.4-氯酚对厌氧生物降解葡萄糖反应的抑制作用,在低浓度时发生在反应后期,高浓度时发生在反应初期.同时在恢复试验中不同浓度的4-氯酚对产甲烷的抑制作用仍存在,但有所降低.

  2. Bioremediation of soils contaminated with polycyclic aromatic hydrocarbons, petroleum, pesticides, chlorophenols and heavy metals by composting: Applications, microbes and future research needs.

    Science.gov (United States)

    Chen, Ming; Xu, Piao; Zeng, Guangming; Yang, Chunping; Huang, Danlian; Zhang, Jiachao

    2015-11-01

    Increasing soil pollution problems have caused world-wide concerns. Large numbers of contaminants such as polycyclic aromatic hydrocarbons (PAHs), petroleum and related products, pesticides, chlorophenols and heavy metals enter the soil, posing a huge threat to human health and natural ecosystem. Chemical and physical technologies for soil remediation are either incompetent or too costly. Composting or compost addition can simultaneously increase soil organic matter content and soil fertility besides bioremediation, and thus is believed to be one of the most cost-effective methods for soil remediation. This paper reviews the application of composting/compost for soil bioremediation, and further provides a critical view on the effects of this technology on microbial aspects in contaminated soils. This review also discusses the future research needs for contaminated soils. PMID:26008965

  3. Robustness test of a headspace solid-phase microextraction method for the determination of chloroanisoles and chlorophenols related to cork taint in wine using experimental design.

    Science.gov (United States)

    Pizarro, C; Martínez-Uruñuela, A; Pérez-Del-Notario, N; González-Sáiz, J M

    2008-10-24

    A robustness test of a solid-phase microextraction-based method optimised for the simultaneous determination of chloroanisoles and acetyl-chlorophenols implicated in the presence of corky taste in wine has been carried out using a hybrid experimental design. The influence of small changes around the nominal level of four factors (Vs/Vt ratio, extraction temperature, exposure time and sample incubation time) on the measured response were evaluated in order to indicate if the method is robust for the experimental range considered. Moreover, it was also necessary to identify the critical parameters in the validated model in order to keep them under strict control. Experimental design provides an effective approach for robustness testing as a part of the analytical method validation. PMID:18790489

  4. Multiple solid-phase microextraction in a non-equilibrium situation. Application in quantitative analysis of chlorophenols and chloroanisoles related to cork taint in wine.

    Science.gov (United States)

    Martínez-Uruñuela, Almudena; González-Sáiz, José Maria; Pizarro, Consuelo

    2005-09-30

    Multiple HS-solid-phase microextraction (MHS-SPME) is a modification of SPME developed for quantitative analysis that avoids possible matrix effects based on an exhaustive analyte extraction from the sample. In this paper, the theory of this process associated with a non-equilibrium situation has been presented. The application of an optimised HS-SPME-based method in the analysis of chloroanisoles and chlorophenols, previously acetylated, associated with the occurrence of cork taint in different red, white and rosé wine samples, has revealed the existence of matrix effects. This fact determines the choice of standard addition as the adequate technique for the quantification of these compounds in real samples. MHS-SPME is proposed as a good alternative technique with respect to HS-SPME because it avoids matrix effects, simplifies the quantification of these compounds in real samples and reduces analysis time, providing sensitivity below chloroanisole sensory threshold with acceptable precision. PMID:16130768

  5. Identification, library synthesis and anti-vibriosis activity of 2-benzyl-4-chlorophenol from cultures of the marine bacterium Shewanella halifaxensis.

    Science.gov (United States)

    Moore, Sarah L; Berthomier, Lucile; Braganza, Chriselle D; MacKichan, Joanna K; Ryan, Jason L; Visnovsky, Gabriel; Keyzers, Robert A

    2016-07-01

    Summer Gut Syndrome (SGS) is caused by various Vibrio bacterial species and can have negative effects on aquaculture farms worldwide. In New Zealand, SGS is caused by Vibrio harveyii infecting King Salmon (Oncorhynchus tshawytscha). To find leads for the prevention of SGS, we screened the inhibitory effects of 16 strains of Shewanella upon V. harveyii growth in competitive solid phase cultures. The detailed investigation of Shewanella halifaxensis IRL548 revealed 2-benzyl-4-chlorophenol (1), a known, commercially available antibacterial agent, as the major bioactive component. Synthesis of a small library of congeners to confirm the natural product identity and to provide a structure-activity relationship for the observed activity was also completed. Compound 1 exhibits moderate activity against two pathogenic microorganisms. PMID:27185331

  6. Bioremediation of soils contaminated with polycyclic aromatic hydrocarbons, petroleum, pesticides, chlorophenols and heavy metals by composting: Applications, microbes and future research needs.

    Science.gov (United States)

    Chen, Ming; Xu, Piao; Zeng, Guangming; Yang, Chunping; Huang, Danlian; Zhang, Jiachao

    2015-11-01

    Increasing soil pollution problems have caused world-wide concerns. Large numbers of contaminants such as polycyclic aromatic hydrocarbons (PAHs), petroleum and related products, pesticides, chlorophenols and heavy metals enter the soil, posing a huge threat to human health and natural ecosystem. Chemical and physical technologies for soil remediation are either incompetent or too costly. Composting or compost addition can simultaneously increase soil organic matter content and soil fertility besides bioremediation, and thus is believed to be one of the most cost-effective methods for soil remediation. This paper reviews the application of composting/compost for soil bioremediation, and further provides a critical view on the effects of this technology on microbial aspects in contaminated soils. This review also discusses the future research needs for contaminated soils.

  7. The Removal of 4-Chlorophenol and Dichloroacetic Acid in Water Using Ti-, Zr- and Ti/Zr-Pillared Bentonites as Photocatalyst

    Directory of Open Access Journals (Sweden)

    Mohamed Houari

    2005-01-01

    Full Text Available Heterogeneous photocatalysis could be alternative remediation technology for water since it does not need the addition of any chemicals and it is suitable for treating low concentrations of pollutant. Although the TiO2 Degussa P 25 is most used photocatalyst its photonic efficiency still low and its recovery from water is considered as an awkward process. In this study the effect of zirconium addition to titanium was investigated. Ti/Zr-pillared montmorillonites have been prepared from natural bentonite and characterized by UV-Vis DRS and X-ray diffraction. The photocatalytic activities have been tested for the removal of 4-chlorophenol and dichloroacetic acid in water. The influence of preparation conditions and the calculation method, on these activities has been investigated. It was found that the photocatalytic activities increase by the addition of zirconium in pillorying process and the calculation by Microwaves (MW improves the photocatalytic activities

  8. Photocatalytic activity of V doped ZnO nanoparticles thin films for the removal of 2- chlorophenol from the aquatic environment under natural sunlight exposure.

    Science.gov (United States)

    Salah, Numan; Hameed, A; Aslam, M; Babkair, Saeed S; Bahabri, F S

    2016-07-15

    Vanadium doped ZnO powders were used as precursors to deposit thin films of V(5+) incorporated ZnO nanoparticles on glass substrates by the pulsed laser deposition technique. The observed variations in Raman signals, visible region shift in the diffuse reflectance spectra along with a small shift in the (101) reflections of the X-ray diffraction (XRD) confirmed the insertion of V(5+) ions in ZnO lattice. No other additional reflection in the XRD results other than ZnO further endorsed the occupation of lattice positions by V entities rather than independent oxide formation. The asymmetric XPS peaks of Zn2p and V2p core levels confirmed the existence of both in the vicinity. The existence of minimal proportion of V(3+) along with V(5+) states varied the alteration of the oxidation states V in the synthetic route. The SEM images at various resolutions displayed the uniform distribution identical nanoparticles without the presence of additional phases in the deposited films. The SEM cross-section measurements revealed the uniform thickness of ∼90 nm of each film, whereas the surface studies of the films were performed by AFM. The as-synthesized films were tested for photocatalytic activity in sunlight illumination for the removal of 2-chlorophenol. The unique feature of the study was the estimation of the photocatalytic activity 20 ppm of 2-chlorophenol by exposing the low exposed area. The degradation of the substrate was measured by liquid phase UV-vis spectroscopy, whereas total organic carbon measurement revealed the mineralization of the substrate. The released Cl(-) ions were also measured by ion chromatography. The estimated flatband potentials and pHzpc values of the V doped materials, by Mott-Schottky analysis and zeta potential measurements respectively, were correlated with the photocatalytic activity. The kinetics of the photocatalytic degradation/mineralization process was estimated and results were correlated with the plausible mechanism. PMID

  9. A novel sol-gel-based amino-functionalized fiber for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, Habib [Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)], E-mail: Bagheri@sharif.edu; Babanezhad, Esmaeil; Khalilian, Faezeh [Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

    2008-05-26

    A novel amino-functionalized polymer was synthesized using 3-(trimethoxysilyl) propyl amine (TMSPA) as precursor and hydroxy-terminated polydimethylsiloxane (OH-PDMS) by sol-gel technology and coated on fused-silica fiber. The synthesis was designed in a way to impart polar moiety into the coating network. The scanning electron microscopy (SEM) images of this new coating showed the homogeneity and the porous surface structure of the film. The efficiency of new coating was investigated for headspace solid-phase microextraction (SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Effect of different parameters influencing the extraction efficiency such as extraction temperature, extraction time, ionic strength and pH was investigated and optimized. In order to improve the separation efficiency of phenolic compounds on chromatography column all the analytes were derivatized prior to extraction using acetic anhydride at alkaline condition. The detection limits of the method under optimized conditions were in the range of 0.02-0.05 ng mL{sup -1}. The relative standard deviations (R.S.D.) (n = 6) at a concentration level of 0.5 ng mL{sup -1} were obtained between 6.8 and 10%. The calibration curves of chlorophenols showed linearity in the range of 0.5-200 ng mL{sup -1}. The proposed method was successfully applied to the extraction from spiked tap water samples and relative recoveries were higher than 90% for all the analytes.

  10. Characterization of an inducible chlorophenol O-methyltransferase from Trichoderma longibrachiatum involved in the formation of chloroanisoles and determination of its role in cork taint of wines.

    Science.gov (United States)

    Coque, Juan-José R; Alvarez-Rodríguez, María Luisa; Larriba, Germán

    2003-09-01

    A novel S-adenosyl-L-methionine (SAM)-dependent methyltransferase catalyzing the O methylation of several chlorophenols and other halogenated phenols was purified 220-fold to apparent homogeneity from mycelia of Trichoderma longibrachiatum CECT 20431. The enzyme could be identified in partially purified protein preparations by direct photolabeling with [methyl-(3)H]SAM, and this reaction was prevented by previous incubation with S-adenosylhomocysteine. Gel filtration indicated that the M(r) was 112,000, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme was composed of two subunits with molecular weights of approximately 52,500. The enzyme had a pH optimum between 8.2 and 8.5 and an optimum temperature of 28 degrees C, with a pI of 4.9. The K(m) values for 2,4,6-trichlorophenol and SAM were 135.9 +/- 12.8 and 284.1 +/- 35.1 micro M, respectively. S-Adenosylhomocysteine acted as a competitive inhibitor, with a K(i) of 378.9 +/- 45.4 micro M. The methyltransferase was also strongly inhibited by low concentrations of several metal ions, such as Cu(2+), Hg(2+), Zn(2+), and Ag(+), and to a lesser extent by p-chloromercuribenzoic acid, but it was not significantly affected by several thiols or other thiol reagents. The methyltransferase was specifically induced by several chlorophenols, especially if they contained three or more chlorine atoms in their structures. Substrate specificity studies showed that the activity was also specific for halogenated phenols containing fluoro, chloro, or bromo substituents, whereas other hydroxylated compounds, such as hydroxylated benzoic acids, hydroxybenzaldehydes, phenol, 2-metoxyphenol, and dihydroxybenzene, were not methylated. PMID:12957890

  11. Evaluation of dispersive liquid-liquid microextraction for the simultaneous determination of chlorophenols and haloanisoles in wines and cork stoppers using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Campillo, Natalia; Viñas, Pilar; Cacho, Juan I; Peñalver, Rosa; Hernández-Córdoba, Manuel

    2010-11-19

    Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) was evaluated for the simultaneous determination of five chlorophenols and seven haloanisoles in wines and cork stoppers. Parameters, such as the nature and volume of the extracting and disperser solvents, extraction time, salt addition, centrifugation time and sample volume or mass, affecting the DLLME were carefully optimized to extract and preconcentrate chlorophenols, in the form of their acetylated derivatives, and haloanisoles. In this extraction method, 1mL of acetone (disperser solvent) containing 30μL of carbon tetrachloride (extraction solvent) was rapidly injected by a syringe into 5mL of sample solution containing 200μL of acetic anhydride (derivatizing reagent) and 0.5mL of phosphate buffer solution, thereby forming a cloudy solution. After extraction, phase separation was performed by centrifugation, and a volume of 4μL of the sedimented phase was analyzed by GC-MS. The wine samples were directly used for the DLLME extraction (red wines required a 1:1 dilution with water). For cork samples, the target analytes were first extracted with pentane, the solvent was evaporated and the residue reconstituted with acetone before DLLME. The use of an internal standard (2,4-dibromoanisole) notably improved the repeatability of the procedure. Under the optimized conditions, detection limits ranged from 0.004 to 0.108ngmL(-1) in wine samples (24-220pgg(-1) in corks), depending on the compound and the sample analyzed. The enrichment factors for haloanisoles were in the 380-700-fold range. PMID:20956005

  12. Photocatalytic activity of V doped ZnO nanoparticles thin films for the removal of 2- chlorophenol from the aquatic environment under natural sunlight exposure.

    Science.gov (United States)

    Salah, Numan; Hameed, A; Aslam, M; Babkair, Saeed S; Bahabri, F S

    2016-07-15

    Vanadium doped ZnO powders were used as precursors to deposit thin films of V(5+) incorporated ZnO nanoparticles on glass substrates by the pulsed laser deposition technique. The observed variations in Raman signals, visible region shift in the diffuse reflectance spectra along with a small shift in the (101) reflections of the X-ray diffraction (XRD) confirmed the insertion of V(5+) ions in ZnO lattice. No other additional reflection in the XRD results other than ZnO further endorsed the occupation of lattice positions by V entities rather than independent oxide formation. The asymmetric XPS peaks of Zn2p and V2p core levels confirmed the existence of both in the vicinity. The existence of minimal proportion of V(3+) along with V(5+) states varied the alteration of the oxidation states V in the synthetic route. The SEM images at various resolutions displayed the uniform distribution identical nanoparticles without the presence of additional phases in the deposited films. The SEM cross-section measurements revealed the uniform thickness of ∼90 nm of each film, whereas the surface studies of the films were performed by AFM. The as-synthesized films were tested for photocatalytic activity in sunlight illumination for the removal of 2-chlorophenol. The unique feature of the study was the estimation of the photocatalytic activity 20 ppm of 2-chlorophenol by exposing the low exposed area. The degradation of the substrate was measured by liquid phase UV-vis spectroscopy, whereas total organic carbon measurement revealed the mineralization of the substrate. The released Cl(-) ions were also measured by ion chromatography. The estimated flatband potentials and pHzpc values of the V doped materials, by Mott-Schottky analysis and zeta potential measurements respectively, were correlated with the photocatalytic activity. The kinetics of the photocatalytic degradation/mineralization process was estimated and results were correlated with the plausible mechanism.

  13. Dinuclear metal(ii)-acetato complexes based on bicompartmental 4-chlorophenolate: syntheses, structures, magnetic properties, DNA interactions and phosphodiester hydrolysis.

    Science.gov (United States)

    Massoud, Salah S; Ledet, Catherine C; Junk, Thomas; Bosch, Simone; Comba, Peter; Herchel, Radovan; Hošek, Jan; Trávníček, Zdeněk; Fischer, Roland C; Mautner, Franz A

    2016-08-01

    A series of dinuclear metal(ii)-acetato complexes: [Ni2(μ-L(Cl)O)(μ2-OAc)2](PF6)·3H2O (1), [Ni2(μ-L(Cl)O)(μ2-OAc)2](ClO4)·CH3COCH3 (2), [Cu2(μ-L(Cl)O)(μ2-OAc)(ClO4)](ClO4) (3), [Cu2(μ-L(Cl)O)(OAc)2](PF6)·H2O (4), [Zn2(μ-L(Cl)O)(μ2-OAc)2](PF6) (5) and [Mn2(L(Cl)-O)(μ2-OAc)2](ClO4)·H2O (6), where L(Cl)O(-) = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenolate, were synthesized. The complexes were structurally characterized by spectroscopic techniques and single crystal X-ray crystallography. Six-coordinate geometries with doubly bridged acetato ligands were found in Ni(ii), Zn(ii) and Mn(ii) complexes 1, 2, 5 and 6, whereas with Cu(ii) complexes a five-coordinate species was obtained with 4, and mixed five- and six-coordinate geometries with a doubly bridged dimetal core were observed in 3. The magnetic properties of complexes 1-4 and 6 were studied at variable temperatures and revealed weak to very weak antiferromagnetic interactions in 1, 2, 4 and 6 (J = -0.55 to -9.4 cm(-1)) and ferromagnetic coupling in 3 (J = 15.4 cm(-1)). These results are consistent with DFT calculations performed at the B3LYP/def2-TZVP(-f) level of theory. Under physiological conditions, the interaction of the dinculear complexes 1-5 with supercoiled plasmid ds-DNA did not show any pronounced nuclease activity, but Ni(ii) complexes 1 and 2 revealed a strong ability to unwind the supercoiled conformation of ds-DNA. The mechanistic studies performed on the interaction of the Ni(ii) complexes with DNA demonstrated the important impact of the nickel(ii) ion in the unwinding process. In combination with the DNA study, the phosphatase activity of complexes 1, 3, and 5 was examined by the phosphodiester hydrolysis of bis(2,4-dinitrophenol)phosphate (BDNPP) in the pH range of 5.5-10.5 at 25 °C. The Michaelis-Menten kinetics performed at pH 7 and 10.7 showed that catalytic efficiencies kcat/KM (kcat = catalytic rate constant, KM = substrate binding constant) decrease in the order

  14. 对氯苯酚在酪氨酸酶-碳纳米管修饰电极上的电化学行为%Electrochemistry of p-Chlorophenol on a Tyrosinase-Carbon Nanotube Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    刘华俊; 陈敏; 刘慧宏

    2011-01-01

    The use of electrochemical biosensors has been shown to be a suitable alternative with respect to the conventional well-established analytical techniques for the monitoring of p-chlorophenol.The reactions of p-chlorophenol on a tyrosinase-carbon nanotube modified electrode were explored.The processes contain the oxidation of p-chlorophenol by enzyme catalysis and the electrochemical reduction of the product.The solution pH effects the reactions.The results reveal that the reaction of enzyme catalysis is the controlled step.The current and p-chlorophenol concentration is a linear relationship on the range of 0.12-1.11 mmol·L-1.The limit of detection is calculated to be 14 μmol·L-1.The Michaelis constant is estimated to be K_m=163 μmol·L-1.%研究了对氯苯酚在酪氨酸酶-碳纳米管修饰电极上的酶催化氧化和电化学还原过程.实验表明,酶催化反应和电化学反应均受溶液pH值的影响,酶催化反应为控制步骤.对氯苯酚的浓度在0.12~1.11 mmol.L-1范围内,与电流呈线性关系,检出限为14μmol.L-1.酶催化反应的表观米氏常数Km=163μmol.L-1.

  15. Simultaneous derivatization and extraction of chlorophenols in water samples with up-and-down shaker-assisted dispersive liquid-liquid microextraction coupled with gas chromatography/mass spectrometric detection.

    Science.gov (United States)

    Wang, Ke-Deng; Chen, Pai-Shan; Huang, Shang-Da

    2014-03-01

    A new up-and-down shaker-assisted dispersive liquid-liquid microextraction (UDSA-DLLME) for extraction and derivatization of five chlorophenols (4-chlorophenol, 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2,4,6-trichloro-phenol, and pentachlorophenol) has been developed. The method requires minimal solvent usage. The relatively polar, water-soluble, and low-toxicity solvent 1-heptanol (12 μL) was selected as the extraction solvent and acetic anhydride (50 μL) as the derivatization reagent. With the use of an up-and-down shaker, the emulsification of aqueous samples was formed homogeneously and quickly. The derivatization and extraction of chlorophenols were completed simultaneously in 1 min. The common requirement of disperser solvent in DLLME could be avoided. After optimization, the linear range covered over two orders of magnitude, and the coefficient of determination (r (2)) was greater than 0.9981. The detection limit was from 0.05 to 0.2 μg L(-1), and the relative standard deviation was from 4.6 to 10.8 %. Real samples of river water and lake water had relative recoveries from 90.3 to 117.3 %. Other emulsification methods such as vortex-assisted, ultrasound-assisted, and manual shaking-enhanced ultrasound-assisted methods were also compared with the proposed UDSA-DLLME. The results revealed that UDSA-DLLME performed with higher extraction efficiency and precision compared with the other methods. PMID:23727731

  16. Zinc oxide-copper oxide nanoplates composite as coating for solid phase microextraction combined with high performance liquid chromatography-UV detection for trace analysis of chlorophenols in water and tomato juice samples.

    Science.gov (United States)

    Alizadeh, Reza; Kashkoei, Parvin Khodaei; Kazemipour, Maryam

    2016-05-01

    In the present research, the ZnO-CuO nanoplate composite (ZCNC), solid-phase microextraction (SPME) fiber coating, was prepared and its extraction capability for certain chlorophenols (CPs) was studied through directly sampling the typical CPs mixed standard solution of 4-chlorophenol, 2,3-dichlorophenol, 2,5-dichlorophenol, and 2,4,6-trichlorophenol with high performance liquid chromatography. ZCNC thickness was in the range of 50-65 nm. The effective variables on ZCNC-SPME extraction efficiency were extraction time, salt percentage, and desorption time. Accordingly, a multivariate strategy was applied based on an experimental design by using central composite design for optimizing the significant factors affecting the extraction efficiency. The detection limit and relative standard deviation (RSD) (n = 6), that include repeatability and reproducibility as the target analytes, were in the range of 0.5-5 ng ml(-1) and 5.1-14 % of standard solutions at 50 ng ml(-1) concentration of CPs, respectively. The developed technique is believed to be successfully applicable to preconcentration and determination of target analytes in environmental water and tomato juice samples. Graphical Abstract Application of zinc oxide-copper oxide nanoplates composite for extraction of chlorophenols in water and tomato juice samples and optimizing condition by experimental design method. PMID:26995010

  17. 1H-MAS-NMR Chemical Shifts in Hydrogen-Bonded Complexes of Chlorophenols (Pentachlorophenol, 2,4,6-Trichlorophenol, 2,6-Dichlorophenol, 3,5-Dichlorophenol, and p-Chlorophenol and Amine, and H/D Isotope Effects on 1H-MAS-NMR Spectra

    Directory of Open Access Journals (Sweden)

    Hisashi Honda

    2013-04-01

    Full Text Available Chemical shifts (CS of the 1H nucleus in N···H···O type hydrogen bonds (H-bond were observed in some complexes between chlorophenols [pentachlorophenol (PCP, 2,4,6-tricholorophenol (TCP, 2,6-dichlorophenol (26DCP, 3,5-dichlorophenol (35DCP, and p-chlorophenol (pCP] and nitrogen-base (N-Base by solid-state high-resolution 1H-NMR with the magic-angle-spinning (MAS method. Employing N-Bases with a wide range of pKa values (0.65–10.75, 1H-MAS-NMR CS values of bridging H atoms in H-bonds were obtained as a function of the N-Base’s pKa. The result showed that the CS values were increased with increasing pKa values in a range of DpKa 2: The maximum CS values was recorded in the PCP (pKa = 5.26–4-methylpyridine (6.03, TCP (6.59–imidazole (6.99, 26DCP (7.02–2-amino-4-methylpyridine (7.38, 35DCP (8.04–4-dimethylaminopyridine (9.61, and pCP (9.47–4-dimethylaminopyridine (9.61 complexes. The largest CS value of 18.6 ppm was recorded in TCP–imidazole crystals. In addition, H/D isotope effects on 1H-MAS-NMR spectra were observed in PCP–2-amino-3-methylpyridine. Based on the results of CS simulation using a B3LYP/6-311+G** function, it can be explained that a little changes of the N–H length in H-bond contribute to the H/D isotope shift of the 1H-MAS-NMR peaks.

  18. Studies on the Quantitative Structure-activity Relationship of Toxicity of Chlorophenol Serial Compounds in the ab initio Methods and Substitutive Position of Chlorine Atom (NPCS)

    Institute of Scientific and Technical Information of China (English)

    ZHENG Qing; WANG Lian-Sheng

    2007-01-01

    20 Quantum chemical parameters of chlorophenol compounds were fully optimized by using B3LYP method on both 6-31G* and 6-311G* basis sets. These structural parameters are taken as theoretical descriptors, and the experimental data of 20 compounds' aquatic photogen toxicity(-1gEC50) are used to perform stepwise regression in order to obtain two predicted -lgEC50 correlation models whose correlation coefficients R2 are respectively 0.9186 and 0.9567. In addition, parameters of chlorine atom's substitutive positions and their correlations (NPCs) are taken as descriptors to obtain another predicted -1gEC50 model with the correlation coefficient R2 of 0.9444. Correlation degree of each independent variable in the three models is verified by using variance inflation factors (VIF) and t value. In the cross-validation method, cross-validation coefficients q2 of 3 models are respectively 0.8748, 0.9119 and 0.8993, which indicates that the relativity and prediction ability of this model are superior to those of the model obtained by topological and BLYP methods.

  19. Magnetic porous carbon derived from a Zn/Co bimetallic metal-organic framework as an adsorbent for the extraction of chlorophenols from water and honey tea samples.

    Science.gov (United States)

    Li, Menghua; Wang, Junmin; Jiao, Caina; Wang, Chun; Wu, Qiuhua; Wang, Zhi

    2016-05-01

    A novel magnetic porous carbon derived from a bimetallic metal-organic framework, Zn/Co-MPC, was prepared by introducing cobalt into ZIF-8. Magnetic porous carbon that possesses magnetic properties and a large specific surface area was firstly fabricated by the direct carbonization of Zn/Co-ZIF-8. The prepared magnetic porous carbon material was characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, N2 adsorption, and vibrating sample magnetometry. The prepared magnetic porous carbon was used as a magnetic solid-phase extraction adsorbent for the enrichment of chlorophenols from water and honey tea samples before high-performance liquid chromatography analysis. Several experimental parameters that could influence the extraction efficiency were investigated and optimized. Under the optimum conditions, good linearities (r > 0.9957) for all calibration curves were obtained with low limits of detection, which are in the range of 0.1-0.2 ng mL(-1) for all the analytes. The results showed that the prepared magnetic porous carbon had an excellent adsorption capability toward the target analytes. PMID:26991637

  20. Quantum chemical analysis of the energy of proton transfer from phenol and chlorophenols to H2O in the gas phase and in aqueous solution

    Science.gov (United States)

    Schüürmann, Gerrit

    1998-12-01

    Proton transfer energies of phenol and 14 chlorophenols with H2O as a base are analyzed in the gas phase and in solution using quantum chemical methods at the semiempirical and ab initio level of computation. The effect of aqueous solution was accounted for by applying the density functional theory (DFT) implementation of the conductor-like screening model (COSMO) as well as semiempirical continuum-solvation models. The results reveal substantial and systematic overestimations of the free energies of proton transfer as derived from experimental solution-phase pKa data. This can be traced back to both deficiencies in the current model parameterization as well as to limitations of the underlying gas-phase quantum chemical models, which is further illustrated by additional complete-basis-set (CBS) calculations for the proton transfer reaction with phenol. In contrast, the relative pKa trend is reflected well by COSMO-DFT calculations with correlation coefficients (adjusted for degrees of freedom) of 0.96. Decomposition of the dissociation energy in aqueous solution into a gas-phase term and a term summarizing the solvation contributions provides new insights into the effect of solvation on proton transfer energies, and yields mechanistic explanations for the observed differences in the gas-phase and solution-phase acidity orders of various subgroups of the compounds.

  1. Synergistic photocatalysis of Cr(VI) reduction and 4-Chlorophenol degradation over hydroxylated α-Fe2O3 under visible light irradiation.

    Science.gov (United States)

    Wang, Ji-Chao; Ren, Juan; Yao, Hong-Chang; Zhang, Lin; Wang, Jian-She; Zang, Shuang-Quan; Han, Li-Feng; Li, Zhong-Jun

    2016-07-01

    A series of Fe2O3 materials with hydroxyl are synthesized in different monohydric alcohol (C2-C5) solvents by solvothermal method and characterized by XRD, BET, XPS, TG and EA. The amount of hydroxyl is demonstrated to be emerged on the surface of the as-synthesized Fe2O3 particles and their contents are determined to be from 7.99 to 3.74 wt%. The Cr(VI) reduction experiments show that the hydroxyl content of Fe2O3 samples exacts great influence on the photocatalytic activity under visible light irradiation (λ>400 nm) and that the Fe2O3 sample synthesized in n-butyl alcohol exhibits the optimal photocatalytic activity. The synergistic photocatalysis for 4-Chlorophenol (4-CP) degradation and Cr(VI) reduction over above Fe2O3 sample is further investigated. The photocatalytic ratio of Cr(VI) reduction are enhanced from 24.8% to 70.2% while that of 4-CP oxidation are increased from 13.5% to 47.8% after 1 h visible light irradiation. The Fe2O3 sample keeps good degradation rates of mixed pollutants after 9 runs. The active oxygen intermediates O2(-)˙, ˙OH and H2O2 formed in the photoreaction process are discovered by ESR measurement and UV-vis test. The photocatalytic degradation mechanism is proposed accordingly. PMID:26954471

  2. Degradation of chlorophenols and alkylphenol ethoxylates, two representative textile chemicals, in water by advanced oxidation processes: the state of the art on transformation products and toxicity.

    Science.gov (United States)

    Karci, Akin

    2014-03-01

    Advanced oxidation processes based on the generation of reactive species including hydroxyl radicals are viable options in eliminating a wide array of refractory organic contaminants in industrial effluents. The assessment of transformation products and toxicity should be, however, the critical point that would allow the overall efficiency of advanced oxidation processes to be better understood and evaluated since some transformation products could have an inhibitory effect on certain organisms. This article reviews the most recent studies on transformation products and toxicity for evaluating advanced oxidation processes in eliminating classes of compounds described as "textile chemicals" from aqueous matrices and poses questions in need of further investigation. The scope of this paper is limited to the scientific studies with two classes of textile chemicals, namely chlorophenols and alkylphenol ethoxylates, whose use in textile industry is a matter of debate due to health risks to humans and harm to the environment. The article also raises the critical question: What is the state of the art knowledge on relationships between transformation products and toxicity? PMID:24216260

  3. Improved 4-chlorophenol dechlorination at biocathode in bioelectrochemical system using optimized modular cathode design with composite stainless steel and carbon-based materials.

    Science.gov (United States)

    Kong, Fanying; Wang, Aijie; Ren, Hong-Yu

    2014-08-01

    This study developed and optimized a modular biocathode materials design in bioelectrochemical system (BES) using composite metal and carbon-based materials. The 4-chlorophenol (4-CP) dechlorination could be improved with such composite materials. Results showed that stainless steel basket (SSB) filled with graphite granules (GG) and carbon brush (CB) (SSB/GG/CB) was optimum for dechlorination, followed by SSB/CB and SSB/GG, with rate constant k of 0.0418 ± 0.0002, 0.0374 ± 0.0004, and 0.0239 ± 0.0002 h(-1), respectively. Electrochemical impedance spectroscopy (EIS) demonstrated that the composite materials with metal can benefit the electron transfer and decrease the charge transfer resistance to be 80.4 Ω in BES-SSB/GG/CB, much lower than that in BES-SSB (1674.3 Ω), BES-GG (387.3 Ω), and BES-CB (193.8 Ω). This modular cathode design would be scalable with successive modules for BES scale-up, and may offer useful information to guide the selection and design of BES materials towards dechlorination improvement in wastewater treatment. PMID:24926596

  4. Direct determination of chlorophenols present in liquid samples by using a supported liquid membrane coupled in-line with capillary electrophoresis equipment.

    Science.gov (United States)

    Almeda, S; Nozal, L; Arce, L; Valcárcel, M

    2007-03-21

    Actually there is a great trend on the development of effective analytical methods for monitoring trace levels of various phenols which can indicate, among others compounds, the water quality. A simple, inexpensive supported liquid membrane (SLM) device was used in combination with commercially available capillary electrophoresis (CE) equipment for the direct determination of chlorophenols in surface water samples. The manifold was used simultaneously to extract and preconcentrate the analytes from liquid samples. In the extraction set-up, the donor phase (4 mL) was placed in the CE vial, where a micro-membrane extraction unit (MMEU) accommodating the acceptor phase (100 microL) in its lumen was immersed. The supported liquid membrane was constructed by impregnating a porous Fluoropore Teflon (PTFE) membrane with a water-immiscible organic solvent (dihexyl ether). The extraction process was optimized with regard to the pH of the donor and acceptor phases, membrane liquid, extraction time and voltage applied to the inlet or outlet vial during extraction. The chlorinated phenols pentachlorophenol (PCP), 2,3,6 trichlorophenol (TCP) and 2,6 dichlorophenol (DCP) were thus efficiently separated by CE, using tris(hydroxymethyl)aminomethane (Tris) and an NaH(2)PO(4) solution containing 1% (v/v) methanol at pH 10.5 as running buffer. PMID:17386759

  5. In-syringe dispersive micro-solid phase extraction using carbon fibres for the determination of chlorophenols in human urine by gas chromatography/mass spectrometry.

    Science.gov (United States)

    García-Valverde, M T; Lucena, R; Cárdenas, S; Valcárcel, M

    2016-09-16

    In this article, carbon fibres (CFs) are presented as sorbent material for the dispersive micro-solid phase extraction of twelve chlorophenols from urine samples. CFs are synthesized by a reagentless and green procedure consisting of heating raw cotton, a natural precursor, at high temperature (400°C) in an inert atmosphere (Ar) during 2h. The resulting fibres, which present good water dispersibility, are finally loaded on an in-syringe device. This device, which integrates the extraction and final elution of the analytes, is disposable and it is adapted to process low sample volumes. Working at the optimum conditions, the extraction procedure in combination with gas chromatography/mass spectrometry allows the determination of the analytes in urine at the low μg/L range. In fact, the limits of quantification (LOQs) of the analytes were in the interval from 1μg/L to 2.5μg/L with precision values, expressed as relative standard deviations (RSD), better than 13%. Relative recovery values, ranging from 74.5% to 113%, demonstrate the applicability of the proposed method. PMID:27558356

  6. Two heterometallic-organic frameworks composed of iron(III)-salen-based ligands and d(10) metals: gas sorption and visible-light photocatalytic degradation of 2-chlorophenol.

    Science.gov (United States)

    Li, Jing; Yang, Jin; Liu, Ying-Ying; Ma, Jian-Fang

    2015-03-01

    Two examples of heterometallic-organic frameworks (HMOFs) composed of dicarboxyl-functionalized Fe(III)-salen complexes and d(10) metals (Zn, Cd), [Zn2(Fe-L)2(μ2-O)(H2O)2]⋅4 DMF⋅4 H2O (1) and [Cd2(Fe-L)2(μ2-O)(H2O)2]⋅2 DMF⋅H2O (2) (H4L = 1,2-cyclohexanediamino-N,N'-bis(3-methyl-5-carboxysalicylidene), have been synthesized and structurally characterized. In 1 and 2, each square-pyramidal Fe(III) atom is embedded in the [N2O2] pocket of an L(4-) anion, and these units are further bridged by a μ2-O anion to give an (Fe-L)2(μ2-O) dimer. The two carboxylate groups of each L(4-) anion bridge Zn(II) or Cd(II) atoms to afford a 3D porous HMOF. The gas sorption and magnetic properties of 1 and 2 have been studied. Remarkably, 1 and 2 show activity for the photocatalytic degradation of 2-chlorophenol (2-CP) under visible-light irradiation, which, to the best of our knowledge, is the first time that this has been observed for Fe(III)-salen-based HMOFs.

  7. 突变株CTM2降解苯酚和4-氯酚的生物降解特性%Biodegradation of Phenol and 4-Chlorophenol by the Mutant Strain CTM 2

    Institute of Scientific and Technical Information of China (English)

    姜岩; 任南琪; 蔡徇; 吴迪; 乔丽艳; 林森

    2008-01-01

    The biodegradations of phenol and 4-chlorophenol(4-cp)were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis.The results showed that the capacity of the CTM 2 to biodegrade 4-cp was increased up to 400 mg.L-1 within 59.5 h.In the dual.substrate biodegradation,both 2 to degrade phenol.In addition,the kinetic behaviors were described using the kinetic model proposed in this lab.

  8. Planar graphene oxide-based magnetic ionic liquid nanomaterial for extraction of chlorophenols from environmental water samples coupled with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cai, Mei-Qiang; Su, Jie; Hu, Jian-Qiang; Wang, Qian; Dong, Chun-Ying; Pan, Sheng-Dong; Jin, Mi-Cong

    2016-08-12

    A planar graphene oxide-based magnetic ionic liquid nanomaterial (PGO-MILN) was synthesized. The prepared PGO-MILN was characterized by transmission electronmicroscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The results of adsorption experiments showed that the PGO-MILN had great adsorption capacity for 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on the adsorption experimental data, a sensitive magnetic method for determination of the five CPs in environmental water samples was developed by an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effects of main MSPE parameters including the solution pH, extraction time, desorption time, and volume of desorption solution on the extraction efficiencies had been investigated in detail. The recoveries ranged from 85.3 to 99.3% with correlation coefficients (r) higher than 0.9994 and the linear ranges were between 10 and 500ngL(-1). The limits of detection (LODs) and limits of quantification (LOQs) of the five CPs ranged from 0.2 to 2.6ngL(-1) and 0.6 to 8.7ngL(-1), respectively. The intra- and inter- day relative standard deviations (RSDs) were in the range from 0.6% to 7.4% and from 0.7% to 8.4%, respectively. It was confirmed that the PGO-MILN was a kind of highly effective MSPE materials used for enrichment of trace CPs in the environmental water. PMID:27425762

  9. Rapid photo-degradation of 2-chlorophenol under visible light irradiation using cobalt oxide-loaded TiO2/reduced graphene oxide nanocomposite from aqueous media.

    Science.gov (United States)

    Sharma, Ajit; Lee, Byeong-Kyu

    2016-01-01

    The photocatalytic removal of 2-chlorophenol (2-CP) from water environment was investigated by TiO2-RGO-CoO. Cobalt oxide-loaded TiO2 (TiO2-CoO) supported with reduced graphene oxide (RGO) was synthesized using a sol-gel method and then annealed at 500 °C for 5 min. The material characteristics were analyzed by UV-Vis analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Incorporation of cobalt oxide and RGO into the TiO2 system (TiO2-RGO-CoO) lowered the band gap energy to 2.83 eV, which greatly enhanced the visible light absorption. The TiO2-RGO-CoO photocatalyst showed complete removal of 20 mg/L 2-CP within 8 h with the addition of 0.01% H2O2 under 100 W visible light irradiation. The photo-degradation efficiency of 2-CP (10 mg/L) was 35.2, 48.9, 58.9 and 98.2% for TiO2, TiO2-RGO, TiO2-CoO and TiO2-RGO-CoO, respectively, in the presence of visible light irradiation at solution pH of 6.0. The TiO2-RGO-CoO photocatalyst retained its high removal efficiency even after five photocatalytic cycles. PMID:26386660

  10. Planar graphene oxide-based magnetic ionic liquid nanomaterial for extraction of chlorophenols from environmental water samples coupled with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cai, Mei-Qiang; Su, Jie; Hu, Jian-Qiang; Wang, Qian; Dong, Chun-Ying; Pan, Sheng-Dong; Jin, Mi-Cong

    2016-08-12

    A planar graphene oxide-based magnetic ionic liquid nanomaterial (PGO-MILN) was synthesized. The prepared PGO-MILN was characterized by transmission electronmicroscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The results of adsorption experiments showed that the PGO-MILN had great adsorption capacity for 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on the adsorption experimental data, a sensitive magnetic method for determination of the five CPs in environmental water samples was developed by an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effects of main MSPE parameters including the solution pH, extraction time, desorption time, and volume of desorption solution on the extraction efficiencies had been investigated in detail. The recoveries ranged from 85.3 to 99.3% with correlation coefficients (r) higher than 0.9994 and the linear ranges were between 10 and 500ngL(-1). The limits of detection (LODs) and limits of quantification (LOQs) of the five CPs ranged from 0.2 to 2.6ngL(-1) and 0.6 to 8.7ngL(-1), respectively. The intra- and inter- day relative standard deviations (RSDs) were in the range from 0.6% to 7.4% and from 0.7% to 8.4%, respectively. It was confirmed that the PGO-MILN was a kind of highly effective MSPE materials used for enrichment of trace CPs in the environmental water.

  11. 2-氯酚污染土壤原位臭氧化修复的数学模型%Mathematical Model of In-situ Ozonation for the Remediation of 2-Chlorophenol Contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    张晖; 宋孟浩; 黄金宝

    2003-01-01

    A microscopic diffusion-reaction model was developed to simulate in-situ ozonation for the remediation of contaminated soil, i.e., to predict the temporal and spatial distribution of target contaminant in the subsurface.The sequential strategy was employed to obtain the numerical solution of the model using finite difference method. A non-uniform grid of discretization points was employed to increase the accuracy of the numerical solution by means of coordinate transformation. One-dimensional column tests were conducted to verify the model. The column was packed with simulated soils that were spiked with 2-chlorophenol. Ozone gas passed through the column at a flow time intervals. Compared the experimental data with the simulated values, it was found that the mathematical model fitted data well during most time of the experiment.

  12. Hollow fiber liquid-liquid-liquid microextraction followed by solid-phase microextraction and in situ derivatization for the determination of chlorophenols by gas chromatography-electron capture detection.

    Science.gov (United States)

    Saraji, Mohammad; Ghani, Milad

    2015-10-30

    A method based on the combination of hollow fiber liquid-liquid-liquid microextraction and solid-phase microextraction (SPME) followed by gas chromatography-electron capture detection was developed for the determination of chlorophenols in water and wastewater samples. Silica microstructures fabricated on the surface of a stainless steel wire were coated by an organic solvent and used as a SPME fiber. The analytes were extracted through a hollow fiber membrane containing n-decane from sample solution to an alkaline aqueous acceptor phase. They were then extracted and in situ derivatized on the SPME fiber using acetic anhydride. Experimental parameters such as the type of extraction solvent, acceptor phase NaOH concentration, donor phase HCl concentration, the amount of derivatizing reagent, salt concentration, stirring rate and extraction time were investigated and optimized. The precision of the method for the analytes at 0.02-30μgL(-1) concentration level ranged from 7.1 to 10.2% (as intra-day relative standard deviation) and 6.4 to 9.8% (as inter-day relative standard deviation). The linear dynamic ranges were in the interval of 5-500μgL(-1), 0.05-5μgL(-1), 0.02-1μgL(-1) and 0.001-0.5μgL(-1) for 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol, respectively. The enrichment factors were between 432 and 785. The limits of detection were in the range of 0.0004-1.2μgL(-1). Tap water, well water and wastewater samples were also analyzed to evaluate the method capability for real sample analysis.

  13. Hollow fiber liquid-liquid-liquid microextraction followed by solid-phase microextraction and in situ derivatization for the determination of chlorophenols by gas chromatography-electron capture detection.

    Science.gov (United States)

    Saraji, Mohammad; Ghani, Milad

    2015-10-30

    A method based on the combination of hollow fiber liquid-liquid-liquid microextraction and solid-phase microextraction (SPME) followed by gas chromatography-electron capture detection was developed for the determination of chlorophenols in water and wastewater samples. Silica microstructures fabricated on the surface of a stainless steel wire were coated by an organic solvent and used as a SPME fiber. The analytes were extracted through a hollow fiber membrane containing n-decane from sample solution to an alkaline aqueous acceptor phase. They were then extracted and in situ derivatized on the SPME fiber using acetic anhydride. Experimental parameters such as the type of extraction solvent, acceptor phase NaOH concentration, donor phase HCl concentration, the amount of derivatizing reagent, salt concentration, stirring rate and extraction time were investigated and optimized. The precision of the method for the analytes at 0.02-30μgL(-1) concentration level ranged from 7.1 to 10.2% (as intra-day relative standard deviation) and 6.4 to 9.8% (as inter-day relative standard deviation). The linear dynamic ranges were in the interval of 5-500μgL(-1), 0.05-5μgL(-1), 0.02-1μgL(-1) and 0.001-0.5μgL(-1) for 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol, respectively. The enrichment factors were between 432 and 785. The limits of detection were in the range of 0.0004-1.2μgL(-1). Tap water, well water and wastewater samples were also analyzed to evaluate the method capability for real sample analysis. PMID:26411480

  14. 多酚氧化酶在非水相中催化对氯苯酚氧化反应的动力学研究%Kinetics Studies On Polyphenoloxidase Catalize P-chlorophenol Oxidzing Reaction in onaqueous System

    Institute of Scientific and Technical Information of China (English)

    李华; 霍瑞贞

    2000-01-01

      本文用丙酮沉淀法从蘑菇中提取多酚氧化酶,以多孔玻璃粉为载体,用吸附沉积法将酶固定,研究了该酶在氯仿介质中催化对氯苯酚氧化反应的机理遵循米氏(Michaelis-Menten)动力学方程;而且,在有机介质中含水率大小直接影响酶的催化活性.实验测得反应的最佳条件为pH=7.0,温度为25°C,含水率为0.5%(v/v);表观活化能Ea=29.54kJ . mol-1,米氏常数Km=1.058mol . dm-3,最大反应速率rmax=90.74×10-3min-1.%  In experiment,the polyphenoloxidase was extracted from mushroom by using acetone precipitating method threetimes. And then, it was immobilized by using the absorbentdeposition method with porous glass powder as carriers,It wasstudied to catalize p-chlorophenol oxidizing reaction inchloroform, complys with Michaelis-Menten dynamicmodel.And themoisture content in organic solvent directly affected thecatalytic activity of mushroom polyphenoloxidase. Theoptimum reaction condition for the catalyrtic oxidation of p-chlorophenol in chloroform was determined: pH:7, temperature:25°C, moisture content: 0.5%(v/v).The measured value of dynamic parameters was 29.45kJ. mol-1 for apparent activationenergy,1.058mol. L-1 for Michaelis-Menten kinetics and 9.074×10-2 min-1 for the maximum reaction rate.

  15. 硝氯粉和肝蛭净驱除绵羊肝片吸虫效果的对比试验%Effect of NOx Chlorophenol and Liver Fluke Net against Fasciola Hepatica in Sheep

    Institute of Scientific and Technical Information of China (English)

    才项吉

    2012-01-01

    应用硝氯粉和肝蛭净两种药物,采取口服投药方式,分不同剂量,在绵羊肝片吸虫驱虫方面做了对比试验。结果表明:硝氯粉按5mg/kg体重驱虫,肝片吸虫虫卵减少率96.85%;肝蛭净按12mg/kg体重驱虫,虫卵减少率96.74%:二者的驱虫效果差异不大,但在实际操作中,硝氯粉剂量稍大会出现中毒反应,剂量过小则效果不佳,硝氯粉剂量较难控制。建议养畜户在绵羊肝片吸虫驱虫时最好用肝蛭净。%Sheep were used to experiment on effect of NOx ehlorophenol and liver flukd net against Faseiola hepatica. The result showed that the reductive rate of eggs with NOx chlorophenol in dose of 3mg/kg. b w and 5mg/kg . b w were 75.18% and 96.80% ,respectively. The reduetive rate of eggs with liver fluke net in dose of 7mg/kg. b w and 12mg/kg were 67.2% and 100.0%, respectively. The liver fluke net was well than that of NOx chlorophenol for safe and effect.

  16. 超顺磁性氧化石墨烯复合材料固定辣根过氧化物酶催化去除氯酚%Enzymatic removal of chlorophenols using horseradish peroxidase immobilized on superparamagnetic Fe3O4/graphene oxide nanocomposite

    Institute of Scientific and Technical Information of China (English)

    常青; 江国栋; 唐和清; 李娜; 黄佳; 吴来燕

    2015-01-01

    Magnetic Fe3O4nanoparticles were successfully deposited on graphene oxide sheets by ultra-sound-assisted coprecipitation. The nanoparticles were characterized using transmission electron microscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy. The synthe-sized material was used as a support for the immobilization of horseradish peroxidase (HRP). The removals of 2-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol using the immobilized HRP were investigated. Batch degradation studies were used to determine the effects of the initial solu-tion pH values, reaction temperature, reaction time,H2O2and chlorophenol concentrations, and immobilized enzyme dosage on the removal of chlorophenols. The different numbers and positions of electron-withdrawing substituents affected the chlorophenol removal efficiency; the order of the removal efficiencies was 2-chlorophenol< 4-chlorophenol< 2,4-dichlorophenol. The oxidation products formed during chlorophenol degradation were identified using gas chromatography-mass spectrometry. The biochemical properties of the immobilized HRP were investigated; the results indicated that the storage stability and tolerance to changes in pH and temperature of the immobi-lized HRP were better than those of free HRP. The nanoparticles were recovered using an external magnetic field, and the immobilized HRP retained 66% of its initial activity for the first four cycles, showing that the immobilized HRP had moderate stability. These results suggest that the immobi-lized enzyme has potential application in wastewater treatment.%采用超声辅助共沉淀法成功地将磁性Fe3O4纳米颗粒沉积在氧化石墨烯表面,利用透射电镜、磁滞回归曲线和X射线光电子能谱对材料进行了表征。将该材料作为载体固定辣根过氧化物酶,考察了固定化酶催化2-氯酚、4-氯酚和2,4-二氯酚降解反应,研究了溶液pH值、反应温度、反应时间、H2O2和氯酚浓度以及固定化

  17. 衍生化吹扫捕集-气相色谱-质谱法测定饮用水中的6种氯酚%Determination of Six Chlorophenols in Drinking Water by Derevitazation Purge-and-Trap GC-MS

    Institute of Scientific and Technical Information of China (English)

    易睿; 李利聪; 汪霄; 高娟; 颜峰

    2012-01-01

    建立了饮用水中6种氯酚的检测方法.调节水样pH后,经乙酸酐衍生化、吹扫捕集后经气相色谱-质谱测定,外标法定量.在0.004~0.120mg/L范围内,方法的线性关系良好,相关系数为0.9972~0.9999,加标回收率为94.2%~112%,相对标准偏差为1.88%~5.27%.该方法简便、灵敏度高,完全可以满足饮用水中6种氯酚的痕量检测要求.%A method was developed for the determination of 6 chlorophenols. The sample pH was adjusted by adding potassium cai-bon. Then, acetic anhydride was added. Chlorophenols were derivalized and submitted to the purge-and-trap precocentration system coupled to GC-MS with external standard method. The result indicated that the calibration curves showed good linear relationship and concentration in the range of 0. 004 ~ 0. 120mg/L. The correlation coefficients were in the range of 0. 9972 ~ 0. 9999. The recoveries of 6 chlorophenols were in range of 94. 2% - 112% and the relative standard deviations of 1. 88% ~ 5. 27% . The method was simple and sensitive and was suitable for the determination of 6 chlorophenols in drinking water.

  18. 白假丝酵母PDY-07厌氧生物降解4-氯酚的研究%Biodegradation of 4-Chlorophenol by Candida albicans PDY-07 under Anaerobic Conditions

    Institute of Scientific and Technical Information of China (English)

    闻建平; 李红梅; 白静; 姜岩

    2006-01-01

    Candida albicans PDY-07 was isolated from activated sludge under anaerobic conditions and identified as a member belonging to the genus Candida. Pure culture of C. albicans PDY-07, biodegradation of 4-chlorophenol (4-CP) was carried out under anaerobic conditions in Erlenmeyer flasks at 35 ℃, with an initial pH of 7.0-7.2 and a starting inoculum of 10% (by volume). The results showed that, under the above-mentioned conditions, C. albicans PDY-07 could thoroughly biodegrade 4-CP up to a concentration of 300 mg·L-1 within 244h and that it had a high tolerance potential of up to 440 mg·L-1 for 4-CP. With the increase in the initial concentrations of 4-CP, substrate inhibition was obviously enhanced. There was increased consumption of 4-CP, which was not assimilated by the cell for growth but was used to counteract the strong substrate inhibition. In addition, the cell growth and substrate-degradation kinetics of 4-CP as the sole source of carbon and energy for the strain in batch cultures were also investigated over a wide range of substrate concentrations (2.2-350 mg·L-1), using the proposed cell growth and degradation kinetic models. The results recorded from these experiments showed that the proposed kinetic models adequately described the dynamic behavior of 4-CP biodegradation by C. albicans PDY-07.

  19. Tyrosinase-modified carbon felt-based flow-biosensors: The role of ultra-sonication in shortening the enzyme immobilization time and improving the sensitivity for p-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    Yue Wang; Yasushi Hasebe

    2011-01-01

    Tyrosinase (TYR) was covalently immobilized onto amino-functionalized carbon felt surface via glutaraldehyde-coupling under ultrasonic treatment for 10 min. The resulting TYR-immobilized carbon felt was used as a working electrode unit of bioelectrocatalytic flow-through detector for TYR substrates (catechol, p-chlorophenol (p-CP), p-cresol, phenol etc.). Cathodic peak currents based on the electroreducfion of enzymatically produced o-quinones were detected at -50 mV vs. Ag/AgC1. Compared with previous work in which TYR was immobilized onto amino-functionalized carbon felt for 16 hr without the ultrasonic treatment, we succeeded in (1) shortening the enzyme immobilization time from 16 hr to 10 min, (2) enhancing the sensitivity of p-CP, and (3) improving the operational stability of p-CP. The ultrasonic treatment during the TYR immobilization step would lead to certain changes in the structure of the immobilized TYR and the morphology of the immobilized TYR-layer on the carbon felt surface.

  20. Removal of 4-Chlorophenol with Fe3O4 Nanoparticles/H2O2 System at High pH%高pH条件纳米Fe3O4催化H2O2分解去除水中4-氯酚

    Institute of Scientific and Technical Information of China (English)

    赵志伟; 师杰; 刘杰

    2015-01-01

    In this paper, removal of 4⁃chlorophenom in aqueous solution with Fe3O4/H2O2 system was carried out at pH 5 to evaluate the catalytic efficiency of Fe3O4 to H2O2. The results showed that the as⁃synthesized nanoparticles was pure Fe3O4 and had an inverse spinel structure. Fe3O4 had a high catalytic activity for the H2O2 decomposition to oxidize the 4⁃chlorophenol in aqueous solution. The removal efficiency of 4⁃chlorophenol can reached 96.8%after 180 min. When the dosage of Fe3O4 was lower than 2.0 g/L, the removal efficiency of 4⁃chlorophenol was directly proportional to the dosage of Fe3O4, but inversely to the dosage of Fe3O4 when it was higher than 2.0 g/L. With the increase of the H2O2 dosage, the removal rate of 4⁃chlorophenol first increased and then reduced gradually. The initial pH of solution had great effect on the 4⁃chlorophenol removal. The lower pH lead to the higher removal effi⁃ciency of 4⁃chlorophenol. The catalytic activity of Fe3O4 was still high after 5 repeated experiments.%为了克服非均相fenton催化反应中溶液初始pH过低的缺点,开展了pH=5时Fe3O4/H2O2体系催化氧化去除水中4-氯酚实验。试验结果表明:制备的铁氧化物为纯Fe3O4,具有反尖晶石八面体结构。纳米Fe3O4能够高效催化H2O2分解氧化水中的4-氯酚,反应180 min后4-氯酚的去除率达到96.8%。当催化剂投量小于2.0 g/L,4-氯酚的去除率随着催化剂投量的增加而升高;当催化剂投量大于2.0 g/L,去除率会随着投量的增加而降低。随着H2O2投量的增加,4-氯酚的去除率先升高后降低。溶液的初始pH对4-氯酚的去除影响较大,pH越低,去除速率和效率越高。重复使用5次以后,纳米Fe3O4仍然保持较高的催化活性。

  1. Adsorption Isotherms of Phenol and 4-Chlorophenol on Petroleum Asphaltenes Adsorption du phénol et du 4-chlorophénol sur les asphaltènes pétroliers

    Directory of Open Access Journals (Sweden)

    Jaoui M.

    2006-11-01

    Full Text Available The adsorption isotherms for phenol and 4-chlorophenol from water onto asphaltenes flocculated in bulk and asphaltenes deposited on silica were established by frontal analysis chromatography at 293, 298, 303, and 308 K. The adsorption was more important with asphaltenes flocculated in bulk and corresponded to a Freundlich isotherm mechanism. The high adsorbed amount of phenols suggests possible migration of phenols through the loose asphaltene structure. Isotherms observed with the silica coated by asphaltenes showed that adsorption occurs in two stages corresponding probably to two different organizations of solute molecules at the surface. Les isothermes d'adsorption du phénol et du 4-chlorophénol en solution dans l'eau sur des asphaltènes floculés en masse et sur des asphaltènes déposés sur de la silice ont été déterminés par analyse chromatographique frontale à 293, 298, 303 et 308 K. L'adsorption sur des asphaltènes floculés en masse était la plus importante avec des isothermes correspondant à un mécanisme de Freundlich. La quantité élevée de phénols adsorbés suggère une migration possible des molécules du phénol à travers la structure peu compacte des asphaltènes. Les isothermes observés dans le cas de silice tapissée d'asphaltènes ont montré que l'adsorption se produit en deux étapes correspondant probablement à deux organisations différentes des molécules de soluté à la surface.

  2. Fotodegradación Solar Heterogénea a Escala Piloto de 4-Clorofenol en un Reactor Cilindro Parabólico Compuesto (CPC Pilot Scale Heterogeneous Solar Photodegradation of 4-Chlorophenol in a Cylindrical Parabolic Composed Reactor (CPC

    Directory of Open Access Journals (Sweden)

    Nhora Suaterna-Ortíz

    2012-01-01

    Full Text Available Se presenta información experimental para la fotodegradación heterogénea del 4-clorofenol con TiO2-P25, en reactores solares a escala piloto del tipo cilindro parabólico compuesto (CPC. Se evaluó el efecto del pH y la concentración de catalizador sobre el porcentaje de degradación del substrato. Los reactores utilizados tuvieron diferentes áreas y diferentes volúmenes totales de operación CPC-I: 1.16 m² de área y 20 L; CPC-II: 2.33 m² y 50 L; CPC-III: 3.50 m² y 60 L. Se realizó el seguimiento de la degradación por mediciones de ion cloruro, por espectrofotometría UV-Vis y la determinación de color verdadero. Se encontró que las variables de mayor influencia en el proceso fueron el pH y el área del reactor. Se evidenció la formación de sustancias intermediarias que aportaron color al sistema y la desaparición de éstas a medida que se incrementa el área de exposición solar.This study presented experimental information about heterogeneous photodegradation of 4-chlorophenol using TiO2-P25 in cylindrical parabolic composed solar reactor (CPC. The effect of pH and catalyst concentration on the degradation percentage of substrate were determined. The reactors have different areas and different total operating volumes: CPC-I: 1.16 m² de area y 20 L; CPC-II: 2.33 m² y 50 L; CPC-III: 3.50 m² y 60 L. The measurements were done using chloride ion, UV-spectrophotometry and color. It was found that the most influential variables on the process were the pH and the reactor area. Also, the formation of intermediary substances that provided color to the reaction system and the disappearance of them when sun exposure area was increased, were observed.

  3. Simultaneous Removal of Nitrates and P-chlorophenol Using PHBV As Solid Phase Carbon Source%以PHBV为固相碳源同时去除地下水中硝酸盐氮和对氯苯酚的试验研究

    Institute of Scientific and Technical Information of China (English)

    赵兰; 王婷; 吴为中

    2015-01-01

    The co-existence of nitrate and pesticide in groundwater resulting from excessive application of fertilizers and pesticides has become one of potential health threats in China. Batch tests using PHBV as solid carbon source were conducted to simultaneously remove nitrate and p-chlorophenol and to further investigate the effect of p-chlorophenol on denitrification and microbial community. Results indicated that at 50 mg·L-1 of NO3--N, addition of p-chlorophenol would lower overall removal of nitrate while improve denitrification rate after initial inhibition. At 10 mg·L-1 of p-chlorophenol,averageremoval mainly due to biodegradation was found to be 45.4% over 24 hours and corresponding microbial community structure tended to diversity and evenness.%化肥和农药的施用导致中国的地下水中硝酸盐氮和农药污染同时存在,并成为威胁人体健康的重要因素之一。其中氯酚类物质是一类常见的农药,具有高毒性和难降解性。目前,关于固相反硝化用于硝酸盐氮和对氯苯酚同时去除的研究较少,并且对微生物群落结构演变情况的分析还鲜见报道。论文以聚羟基丁酸戊酸共聚酯(PHBV)为反硝化固体碳源,通过序批试验研究同步去除硝酸盐氮和对氯苯酚的效果,并探讨对氯苯酚的加入对反硝化速率的影响;利用末端限制性长度多态性分析(T-RFLP)技术,使用Alu I酶切总细菌16S rRNA,研究对氯苯酚的存在对微生物群落的影响。结果表明,(1)在50 mg·L-1的硝酸盐氮(NO3--N)的浓度水平下,对氯苯酚(4-CP)的加入前后,硝酸盐氮(NO3--N)的去除率为(97.5±1.2)%和(95.3±1.7)%,总体上使去除效果略有降低;在10 mg·L-1的质量浓度水平下,对氯苯酚24 h的平均去除率为45.4%,其去除85.5%是由于微生物的降解作用引起的。(2)从对氯苯酚的加入到第45天的时间内,反硝化速率表现为先下降后上升

  4. Estudio clínico comparativo entre colutorio de p-clorofenol y peróxido de hidrógeno con colutorio de clorhexidina al 0.12% en el crecimiento de placa microbiana y gingivitis Mouthwash comparative study between p-chlorophenol and hydrogen peroxide with chlorhexidine mouthwash 0.12% in the growth of microbial plaque and gingivitis

    Directory of Open Access Journals (Sweden)

    PD Jaña

    2010-08-01

    Full Text Available Se formuló un colutorio a base de p-clorofenol alcanforado y peróxido de hidrógeno, y considerando que no se disponían de antecedentes de eficacia y seguridad del colutorio, se realizó un ensayo clínico para medirlas utilizando un modelo de formación de placa microbiana y gingivitis en un período de cuatro días, como control positivo se uso un colutorio de clorhexidina al 0.12%. Participaron 26 sujetos en un estudio doble ciego cruzado y con distribución aleatoria. El colutorio en base a p-clorofenol alcanforado y peróxido de hidrógeno y el de clorhexidina tuvieron un similar efecto en el control de la formación de placa y antigingivitis. No hubo diferencias entre los acontecimientos adversos observados para el colutorio y el control. Por consiguiente, el colutorio en estudio podría ser una alternativa para el control químico de la placa microbiana y gingivitis en el tratamiento de la enfermedad periodontal.A camphorated p-chlorophenol and hydrogen peroxide-based mouthwash was prepared, and a clinical trial to measure the efficiency and safety records of the mouthwash -considering the lack of them- was carried out using a formation model of microbial plaque and gingivitis over a 4-day period, with a 0.12% chlorhexidine mouthwash as positive control. Twenty-six individuals participated in the randomized double-blind crossover study. The camphorated p-chlorophenol and hydrogen peroxide-based and chlorhexidine mouthwash had a similar effect in controlling the formation of plaque and antigingivitis. There was no difference between the adverse events observed for the mouthwash and the control. Therefore, the mouthwash in study might be an alternative to the chemical control of microbial plaque and gingivitis in the periodontal desease treatment.

  5. Determination of Chlorophenols and Chloroanisols in Wine by Headspace Solid-Phase Microextraction and Gas Chromatography-Tandem Mass Spectrometry%顶空-固相微萃取-气相色谱串联质谱法测定葡萄酒中多种氯酚及氯代茴香醚

    Institute of Scientific and Technical Information of China (English)

    陈树兵; 孟原; 施瑛; 倪梅林; 莫燕霞; 贺小雨

    2012-01-01

    样品中氯酚经乙酰化生成乙酰氯酚后,通过优化萃取头、离子强度、温度、时间等固相微萃取条件后,建立顶空-固相微萃取-气相色谱串联质谱法同时测定测定葡萄酒中的3种氯酚2,4,6-三氯酚(TCP)、2,3,4,6-四氯酚(TeCP)、五氯酚(PCP)以及两种氯代茴香醚2,4,6-三氯苯甲醚(TCA)、五氯苯甲醚(PCA)含量的方法。结果表明:该方法检出限为0.1ng/L,回收率为86.0%~105.9%,相对标准偏差小于16.5%。该方法前处理简单、高效、检测灵敏度高,可应用于进出口葡萄酒中木塞污染物的监控。%A headspace solid-phase microextraction and gas chromatography-tandem mass spectrometric (HS-SPME- GC- MS/MS) method was proposed for the simultaneous determination of three chlorophenols 2,4,6-trichlorophenol (TCP), 2,3,4, 6-tetrachlorophenol (TeCP), pentachlorophenol (PCP) and two chloroanisols including pentachloroanisol (PCA) and 2,4,6- trichloroanisol (TCA) in wine. Chlorophenols from wine samples were acetylated and then analyzed by GC-MS/MS in a multi- reaction monitoring (MRM) mode. Four extraction parameters including extraction fiber, ion strength, extraction temperature and extraction time were optimized. The results showed that the limit of detection of this method was 0.1 ng/L. The average spike recovery rates of five analytes in a positive sample were 86.0%-- 105.9% with a RSD less than 16.5% (n = 5). This method was simple, effective, sensitive and therefore applicable to monitor cork taint in exported and imported wine.

  6. Studies on the Extraction of Phenol, o-Chlorophenol, o-Nitrophenol in Water by Using Liquid-Solid Extraction System Composed of Tween 80/Sodium Citrate%吐温80/柠檬酸钠液固体系萃取水中苯酚、邻氯酚、邻硝基酚的研究

    Institute of Scientific and Technical Information of China (English)

    张剑; 李步海; 孙小梅

    2005-01-01

      研究了吐温80/柠檬酸钠液-固萃取体系对苯酚、邻氯酚和邻硝基酚的适宜萃取条件:吐温80浓度为10.5(vol)%,柠檬酸钠2.6000g• L-1,萃取酸度pH5.95.用该法对水中苯酚、邻氯苯酚、邻硝基苯酚进行萃取,一次回收率分别为96.8%、93.0%、86.2%.当柠檬酸钠是成相盐时,酸度能改变盐的型体,也影响酚的萃取率.讨论其萃取机理,认为酚类物是与吐温80形成氢键而被萃入固相的.%  The proper extraction conditions of phenol, o-chlorophenol and o-nitrophenol were studied by using the liquid-solid extraction system composed of tween80/sodium citrate. They were: 10.5(vol)%Tween80, 2.6000g• L-1 sodium citrate, pH5.95. Under the above-mentioned circumstances, the once recoveries of phenol, o-chlorophenol and o-nitrophenol in analogous water samples are 96.8%, 93.0%, 86.2% respectively. When sodium citrate is as salt separate phase, the acidity of the solution not only can change the shape of sodium citrate, but has the effect on extraction yield (E%) of the phenol substances as well. Through the discussion of the extraction mechanism for Tween80 solid phase, it is stated that the extraction in this system has been achieved by the formation of the hydrogen bond between the phenol compounds and tween80.

  7. Electro-catalytic Oxidation of 2-chlorophenol on a Ultrasonic Doped Bi-PbO2/Ti in Aqueous Solution%超声掺Bi二氧化铅电极电氧化降解2-氯苯酚研究

    Institute of Scientific and Technical Information of China (English)

    李晓乐; 马科友; 苏小莉; 张晓杰; 张琳

    2016-01-01

    Objective To improve the service life, electrocatalytic activity, electrocatalytic selectivity of the Ti-base lead diox-ide electrode for the target pollutant of 2-chlorophenol. Methods In this paper, four different types of Ti-base lead dioxide eletrodes including PbO2/SnO2+Sb2O3/Ti,Bi-PbO2/SnO2+Sb2O3/Ti,PbO2(ultrasonic)/SnO2+Sb2O3/Ti and Bi-PbO2(ultrasonic)/SnO2+Sb2 O3/Ti were prepared by electro-deposition and ultrasonic-associated electro-deposition using Ti web with an SnO2+Sb2 O3 layer obtained by spreading and oxidating polymeric precursor as anodes. The composition of the electrolyte and operating conditions were as follows. The mixed solution of NaF and Pb( NO3 ) 2 or the mixed solution of NaF, Pb( NO3 ) 2 and Bi( NO3 ) 3 was used. The pH of the mixed solution was 2, the coating current density was 0. 04 A/cm2 , the temperature of coating solution was 60 ℃, and the time of electro-deposition was 1 hour. The accelerated service life was determined in sulfuric acid solution. Their electric catalysis and electro catalytic selectivity were analyzed by static anodic polarization curves, the effect of electrolysing 2-chlorphenol solution was tested using the electro-oxidative degradation of 2-chlorophenol as the model response, the morphology and crystal phase of sur-face coating was characterized by scanning electron microscopy and X-ray diffraction. Results The accelerated life of Bi-PbO2( ul-trasonic)/SnO2+Sb2 O3/Ti increased by 54% than PbO2/SnO2+Sb2 O3/Ti. Compared to PbO2/SnO2+Sb2 O3/Ti, the 2-chlorophe-nol removal rate had a 19% increase after 4 hours of electrolysis using Bi-PbO2( ultrasonic)/SnO2+Sb2 O3/Ti as an anode, and the electrolyzer voltage had a 7% reduction. The static anodic polarization curves and the electro-oxidative degradation test of 2-chloro-phenol solution showed the same results. Conclusion Ultrasonic environment in the process of preparation of electrode and doped Bi have a beneficial effect on the performance. Compared with non

  8. Efeito de gomas de mascar contendo clorofenol / peróxido de hidrogênio, xilitol ou clorexidina no fluxo salivar, pH, capacidade tampão e escores salivares de Streptococcus mutans = Effects of chlorophenol / hydrogen peroxide versus xylitol or chlorhexidine as chewing gum on salivary flow rate, pH, buffer capacity and salivary Streptococcus mutans scores

    Directory of Open Access Journals (Sweden)

    Yévenes López, Ismael

    2014-01-01

    Full Text Available Objetivos: Gomas de mascar medicadas são preparações sólidas, de dose única, que devem ser mastigadas por um determinado período de tempo a fim de que um ou mais agentes farmacológicos sejam admnistrados. Neste contexto, gomas de mascar medicadas com três ingredientes farmacêuticos ativos – cânfora, p-clorofenol e peróxido de hidrogênio – foram avaliadas como agentes terapêuticos para cárie dentária. O objetivo deste estúdio foi comparar o efeito de gomas de mascar contendo chlorophenol / peróxido de hidrogênio, xilitol ou clorexidina sobre Streptococos mutans salivares, pH, capacidade tampão, a taxa de secreção salivar. Métodos: Foi realizado estudo duplo-cego, com deliamento de randomização cruzada de tratamento em 24 pacientes. Esses foram submetidos a seis sequências diferentes de tratamento. Gomas de mascar foram administradas três vezes ao dia durante 20 minutos, pela manhã, tarde e noite. No início e no final das três fases de amostras de saliva experimentais foram obtidas para a determinação de pH, capacidade tampão, fluxo salivar e enumeração quantitativa de S. mutans. Resultados: O uso de goma medicado de cânfora com p-clorofenol e peróxido de hidrogénio não modificaram os parâmetros químicos salivares medidos, e reduziram o número de S. mutans, após 7 dias. Gomas de mascar contendo clorexidina reduziram significativamente a contagem quantitativa de S. mutans e a taxa de fluxo salivar em um período de 7 dias. Conclusões: O uso de gomas de mascar medicadas com base de cânfora / p-clorofenol ou com peróxido de hidrogênio não altera significativamente os parâmetros químicos salivares e não reduz significativamente o número de S. mutans após a utilização por período de 7 dias

  9. TiO2光催化降解4-氯苯酚过程中的电分析监测%On-Line Monitoring in Photocatalytic Degrad ation of 4-Chlorophenol by Using Cyclic Voltammetry and UV-Vis Spectrometry

    Institute of Scientific and Technical Information of China (English)

    贺飞; 沈伟韧; 方程; 方佑龄

    2001-01-01

    On-line monitoring in photocatalytic degradation process oforganic compound 4-chlorophenol (4-CP) w as carrie d out by using cyclic voltammetry and UV-Vis spectrometry. The result showed th at the degradation process undertook at least a two-route mechanism to the comp lete mineralization: through redox pairs of benzoquinone(BQ) and hydrobenzoquinone(HQ ) and of hydroxybenzoquinone(HBQ) and hydroxyhydrobenzoquinone(HHQ). UV-Vis spe ctra taken at different time showed the breakage of benzene ring and the complet e mineralization. The electroanalysis was proved to be a proper technique for on -line monitoring as it could detect simultaneously both initial reactants and intermed iates, and thus it is suitable for on-line monitoring and complementary for mec hanism study.%采用循环伏安法和紫外光谱法对有机物的光催化降解进行机理研究和在线监测.以标准光催化剂DegussaP25在紫外光照射下催化降解4-氯苯酚,发现在降解过程中至少有两对氧化还原中间产物:对苯二酚-苯醌和羟基氢醌-羟基苯醌.由4-氯苯酚及中间产物的电极响应,可以观测到它们在光催化降解过程中的含量变化,从而对整个过程实现在线监测,并由此全面了解光催化反应机理.从不同反应时间后测得的紫外光谱可以看到,苯环特征峰逐渐消失.这表明4-氯苯酚的苯环逐渐被打开,直至被彻底降解.

  10. Acute toxicity of benzene, chlorobenzene, phenol, p-chlorophenol on zebrafish,guppy and Xiphophorus helleri%苯、氯苯、苯酚、4-氯酚对斑马鱼、孔雀鱼、剑尾鱼的急性毒性

    Institute of Scientific and Technical Information of China (English)

    邢军

    2011-01-01

    In the research, zebrafish, guppy, and Xiphophorus helleri were used as test fishes to study the acute toxicity of four highly toxic substances benzene, chlorobenzene, phenol, and p-chlorophenol on them through semi static toxicity test. The results indicated that 96 h LC50 of the above chemicals toward zebrafish were 132.22, 28.86, 9.66, and 4.29 mg/L, toward Xiphophorus helleri were 123.76, 27.25, 8.86, 4.29 mg/L, and toward guppy were 131.25, 7.88, 9.33, 4.59 mg/L respectively. The toxicity sequence for the studied chemicals is benzene

  11. Highly Selective Synthesis of Chlorophenols under Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Yawen Xiong

    2016-01-01

    Full Text Available Oxychlorination of various phenols is finished in 60 minutes with high efficiency and perfect selectivity under microwave irradiation. These reactions adopt copper(II chloride (CuCl2 as the catalyst and hydrochloric acid as chlorine source instead of expensive and toxic ones. Oxychlorination of phenols substituted with electron donating groups (methyl, methoxyl, isopropyl, etc. at ortho- and meta-positions is accomplished with higher conversion rates, lower reaction time, and excellent selectivity. A proposed reaction mechanism is deduced; one electron transfers from CuCl2 to phenol followed by the formation of tautomeric radical that can be rapidly captured by chlorine atom and converts into para-substituted product.

  12. Highly Selective Synthesis of Chlorophenols under Microwave Irradiation

    OpenAIRE

    Yawen Xiong; Hongdong Duan; Xia Meng; Zhaoyun Ding; Weichun Feng

    2016-01-01

    Oxychlorination of various phenols is finished in 60 minutes with high efficiency and perfect selectivity under microwave irradiation. These reactions adopt copper(II) chloride (CuCl2) as the catalyst and hydrochloric acid as chlorine source instead of expensive and toxic ones. Oxychlorination of phenols substituted with electron donating groups (methyl, methoxyl, isopropyl, etc.) at ortho- and meta-positions is accomplished with higher conversion rates, lower reaction time, and excellent sel...

  13. Gas-phase polychlorinated naphthalene formation from chlorophenols

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.H.; Mulholland, J.A. [Georgia Inst. of Tech., Atlanta (United States); Ryu, J.Y. [Institute for Energy Utilization, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)

    2004-09-15

    Formation of polychlorinated naphthalenes (PCNs) in combustion processes was observed along with other halogenated aromatic compounds such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Recent studies indicated the strong correlation between several PCN and PCDF isomers in municipal waste incinerator (MWI) fly ash, suggesting that the reaction pathways for the formation of PCN and PCDF might be very similar. Sakai and co-workers also reported that the amount of PCNs formed from the pilot-scale solid wastes incinerator was of the same order of magnitude as PCDD/Fs4. In previous studies in this laboratory, formations of PCNs with PCDDs/PCDFs from chlorinated phenols were observed in gas-phase pyrolysis and oxidation. Recently, we proposed PCN formation pathways from monochlorophenols7 based on reactions known to be formation of naphthalene from the recombination of cyclopentadienyl (CPDyl) radical combining with phenoxy radical coupling. Proposed PCN formation pathways are further extended to explain the isomer distribution of PCN congeners produced during slow combustion of each of the six dichlorophenols (DCPs). In this paper, the congener-specific PCN measurements from DCPs are presented, and PCDD and PCDF measurements are also presented to investigate the correlation between PCN and PCDDs/Fs formation in combustion.

  14. Degradation of chlorophenols by fenton and photo-fenton processes

    OpenAIRE

    BENBACHIR, H.; GUETTAIA, D.; Mokhtari, M

    2012-01-01

    The domestic use and industrial activity, of especially impact among the developed counties, generate high amounts of residual wastewater, whose direct disposal to natural channels causes a considerable effect in the environment. This fact, together with the need to restore this water for new uses, makes practically essential the purification of wastewater to achieve the desired degree of quality. Advanced oxidation processes (AOPs) constituted a promising technology for the treatment of w...

  15. Adsorption of phenol and chlorophenols on pure and modified sepiolite

    OpenAIRE

    Yildiz, A; A. GÜR

    2007-01-01

    In this work, pure sepiolite and sepiolite modified by nitric acid (HNO3), ethylenediaminetetraacetic acid (EDTA) and hexadecyltrimethyl-ammonium (HDTMA) were used ad adsorbents. The changes on the surface were studied by IR spectroscopy. The adsorption of solutions of phenol and phenol derivatives in pure ethanol on these adsorbents were examined by means of gas chromatography. It was found that the adsorption capacities of the clay–organic complexes (sepiolite–EDTA and sepiolite–HDTMA) were...

  16. Adsorption of phenol and chlorophenols on pure and modified sepiolite

    Directory of Open Access Journals (Sweden)

    A. YILDIZ

    2007-05-01

    Full Text Available In this work, pure sepiolite and sepiolite modified by nitric acid (HNO3, ethylenediaminetetraacetic acid (EDTA and hexadecyltrimethyl-ammonium (HDTMA were used ad adsorbents. The changes on the surface were studied by IR spectroscopy. The adsorption of solutions of phenol and phenol derivatives in pure ethanol on these adsorbents were examined by means of gas chromatography. It was found that the adsorption capacities of the clay–organic complexes (sepiolite–EDTA and sepiolite–HDTMA were higher than those of pure sepiolite and sepiolite–HNO3.

  17. Infrared study of some solid chlorophenols. Part 1. Symmetric derivatives

    Science.gov (United States)

    Siguenza, C.; Gonzalez-Diaz, P. F.

    1985-10-01

    The IR spectra of some halogenated symmetric derivatives of phenol in solid state are reported. The CNDO/2 method has been applied to calculate the V2 torsional barrier; this method gives larger values than those obtained from other conventional methods. The origin of the tilt angle in phenols is discussed.

  18. Degradation of chlorobenzoates and chlorophenols by methanogenic consortia

    NARCIS (Netherlands)

    Ennik-Maarsen, K.

    1999-01-01

    Pollution of the environment with chlorinated organic compounds mainly results from (agro)industrial activity. In many studies, biodegradation is examined under anaerobic conditions, because highly chlorinated compounds are more easily degradable under anaerobic than under aerobic conditions. Proble

  19. Schiff Base 2-[(2-Bromo-phenylimino)-methyl]-4-chloro-phenol and Its Copper(Ⅱ) Complex:Synthesis and Crystal Structure%2-[(2-溴苯胺基)甲基]-4-氯苯酚Schiff碱及其铜配合物的合成及晶体结构

    Institute of Scientific and Technical Information of China (English)

    郭亚宁

    2011-01-01

    A Cu(Ⅱ) complex (2) of 2-[(2-bromo-phenylimino)-methyl]-4-chloro-phenol (1) generated from 5-chlorosalicylaldehyde and o-bromoaniline was synthesized and characterized by elemental analysis and single crystal X-ray diffraction.Compound 1 is in the orthorhombic system,space group Pbca with a=0.710 19(12) nm,b=1.308 2(2)nm,c=2.533 3 (5) nm,Mr=310.57,V=2.353 6 (7) nm3,Dc=1.753 g·cm-3,F (000)=1 232,μ=3.700 mm-1,Z=8,R=0.025 0 and wR2=0.055 5.Compound 2 belongs to the monoclinic system,space group P21/c with a=0.956 8(2)nm,b=1.085 3(3) nm,c=1.204 7(3) nm,β=105.965(7)°,V=1.202 8(6) nm3,Mr=682.67,Dc=1.885 g·cm-3,Z=2,μ=4.481 mm-1,F(000)=670,R=0.045 0 and wR2=O.122 5.Compound 1 is stabilized by intermolecular C-H…N and intra-molecular C-H … O hydrogen bonds,C-H…Cl and π…π interaction and further linked into a 2D layer structure.But compound 2 is connected by halogen…halogen and C-H…π hydrogen bond to form a 3D network.CCDC:803365,1; 803366,2.%以5-氯水杨醛和邻溴苯胺为原料合成了一种新的Schiff碱配体2-[(2-溴苯胺基)甲基]-4-氯苯酚(1)(C13H9BrClNO,H2L),继而与过渡金属铜离子配合,得到其配合物2([Cu(C13H8BrClNO)2],CuL2).通过X-射线衍射法对配体及其配合物进行了结构表征.化合物1属正交晶系,Pbca空间群,晶胞参数a=0.710 19(12) nm,b=1.308 2(2) nm,c=2.533 3(5) nm,Mr=310.57,V=2.353 6(7) nm 3,Dc=1.753 g·cm-3,Z=8,μ=3.700 mm-1,Z=8,F(000)=1 232,R=0.025 0,wR=0.055 5;化合物1依靠分子间的C-H…N,C-H…O,C-H…Cl氢键及π-π堆积作用进一步联结成二维网状结构.化合物2属单斜晶系,P21/c空间群,晶胞参数a=0.956 8(2) nm,b=1.085 3(3) nm,c=1.204 7(3) nm,β=105.965(7)°,Mr=682.67,V=1.202 8(6) nm 3,Dc=1.885 g·cm-3,Z=2,μ=4.481 mm-1,F(000)=670,R=0.045 0,wR=0.1225.2依靠分子间C-H…π作用及卤索…卤素作用进一步联结成三维网状结构.

  20. Influence of the particle size of activated mineral carbon on the phenol and chlorophenol adsorption

    International Nuclear Information System (INIS)

    Water pollution by phenolic compounds is a problem that requires a solution since these phenolic compounds are not completely biodegradable, they accumulate through the food chains and they are quite toxic when enter in contact with living organisms. In human beings, ingestion or contact of the skin with this type of compounds produces irritation and damages mainly to the liver and kidneys. In fact, the Environmental Protection Agency of the United States (EPA assigned nine phenolic compounds among the 275 most toxic substances in 1991. Phenols are found in wastewater from agriculture and industry, because phenolic compounds are used as pesticides and in diverse industrial activities. The treatment of this type of water is not simple because they are generally composed of a mixture of residuals with different chemical nature A useful method for the removal of phenols is the adsorption by activated carbon, since this material has a great surface area and it can be regenerated. The adsorption process depends, among other factors, on the activated carbon characteristics. When they are modified, their capacity to remove pollutants from the water changes. The effect of activated carbon particle size on the removal of phenolic compounds has not been completely studied. Therefore, the aim of this work was to determine the influence of the mineral activated carbon particle size on the phenol and 4-chloro phenol adsorption in aqueous solution, on adsorption column system. The results of the present work indicate that the mineral activated carbon particle size has a very important influence on the adsorption of phenol and 4-chloro phenol. When the particles were smaller, the retention quantities of phenol and 4-chloro phenol increased. This behavior was related to the particle characteristics of the mineral activated carbon such as surface area and pore volume, while other factors such as elementary composition of the activated carbon did not influence the adsorption process in an important way. Finally, when the particle size decreased, the saturation percentage decreased as well as the adsorption capacity increased for the studied phenolic compounds. (Author)

  1. Laccase immobilized on mesoporous SiO2 and its use for degradation of chlorophenol pesticides

    Science.gov (United States)

    Yang, Yuxiang; Xu, Yong; Yang, Yiwen; Yang, Huan; Yuan, Hongmin; Huang, Yan; Liu, Xiangnong

    2016-10-01

    In this paper, mesoporous silica with large specific surface area was used to immobilize laccase by the glutaraldehyde cross-linking method, and after screening and optimization experiments, the best enzyme immobilization process conditions were found (25°C, pH 5.4, 4% glutaraldehyde and 0.2 g/L laccase, treatment time 6 h). After that, the removal and degradation ratio of 2,4-dichlorophenol (abbreviated as DCP) under different conditions were also studied. After the degradation process was performed for 6 h at 30°C, pH 5.4, and DCP initial concentration of 50 mg/L in the presence of 0.1 g of immobilized laccase, the removal ratio and the degradation ratio were 42.28 and 15.93%, respectively. Compared with free laccase, the reusability of immobilized laccase is significantly improved.

  2. EQUILIBRIUM ADSORPTION OF CHLOROPHENOLS ON GRANULAR ACTIVATED CARBON. (R825689C002)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Effects of selected operational parameters on efficacy and selectivity of electromembrane extraction. Chlorophenols as model analytes

    OpenAIRE

    Šlampová, A. (Andrea); Kubáň, P. (Pavel); Boček, P. (Petr)

    2014-01-01

    A comprehensive quantitative study, based also on measurements of electric charge passed through the EME system, was carried out, which demonstrates that apart from the pH value, also the nature of counter-ions in donor and acceptor solution plays a significant role in the electrically induced transfer of charged analytes across supported liquid membranes.

  4. Use of Low-cost Adsorbents to Chlorophenols and Organic Matter Removal of Petrochemical Wastewater

    Directory of Open Access Journals (Sweden)

    Aretha Moreira de Oliveira

    2013-11-01

    Full Text Available The removal of 2,4 diclorophenol (2,4-DCF and 2,4,6 trichlorophenol (2,4,6 TCF present in  petrochemical wastewater was evaluated using low-cost adsorbents, such as chitin, chitosan and coconut shells. Batch studies showed that the absorption efficiency for 2,4 DCF and 2,4,6 TCF follow the order: chitosan > chitin > coconut shells. Langmuir and Freundlich models have been applied to experimental isotherms data, to better understand the adsorption mechanisms. Petrochemical wastewater treatment with fixed bed column system using chitinous adsorbents showed a removal of COD (75% , TOG (90% and turbidity (74-89%.

  5. A Desulfitobacterium strain isolated from human feces that does not dechlorinate chloroethenes or chlorophenols

    NARCIS (Netherlands)

    Pas, van de B.A.; Harmsen, H.J.M.; Raangs, G.C.; Vos, de W.M.; Schraa, G.; Stams, A.J.M.

    2001-01-01

    An anaerobic bacterium, strain DP7, was isolated from human feces in mineral medium with formate and 0.02"east extract as energy and carbon source. This rod-shaped motile bacterium used pyruvate, lactate, formate, hydrogen, butyrate, and ethanol as electron donor for sulfite reduction. Other electro

  6. ENHANCED ENZYMATIC REMOVAL OF CHLOROPHENOLS IN THE PRESENCE OF CO-SUBSTRATES. (R823847)

    Science.gov (United States)

    The effect of reactive co-substrates such as guaiacol and 2,6-dimethoxyphenol on the removal of chlorinated phenols by horseradish peroxidase (HRP) and alaccase from the fungus Trametes versicolor was investigated. Addition of 50 mM guaiacol enhanced the precipitation of 4-ch...

  7. Immunochemical methods for biomonitoring of chlorophenols as potential biomarkers of exposure

    OpenAIRE

    Nichkova, Mikaela

    2003-01-01

    [eng] The thesis presents the development of immunochemical methods for detection of trichlorophenols (TCP) in environmental and biological samples. An indirect enzyme linked immunosorbent assay (ELISA) for 2,4,5-TCP has been developed after a rational design of the immunizing hapten chemical structure, and the screening of 12 competitor haptens. The effect of the conjugation degree of the competitors and their homology with the target analyte, the physicochemical parameters (pH, ionic streng...

  8. Pentachlorophenol and cancer risk: Focusing the lens on specific chlorophenols and contaminants

    Science.gov (United States)

    Objective: Pentachlorophenol is a fungicide widely used as a wood preservative, classified in 1999 by the International Agency for Research on Cancer as a “possible human carcinogen”. We review currently available epidemiological research to determine the extent to which recent...

  9. Waste incineration: estimation of the workers' internal exposure to PCB, PAH chlorophenols and other relevant agents

    Science.gov (United States)

    Angerer, Juergen; Heinzow, B.; Reimann, D. O.; Knorz, W.; Lehnert, G.

    1993-03-01

    Fifty-four persons occupied in a municipal waste incinerator were examined with respect to their internal exposure to organic substances which are possibly produced during pyrolysis of organic matter. For this purpose the levels of benzene of blood, polychlorinated biphenyls (PCB) and hexachlorobenzene (HCB) in plasma as well as mono- (MCP), di- (DCP), tri- (TCP), tetra- (TECP) and pentachlorophenols (PCP) and hydroxypyrene in urine have been determined. Four hundred thirty-one men and women were examined for control purposes. Statistical significantly higher values for the workers were found for the excretion of hydroxypyrene 2,5/2,4-DCP, 2,4,5 TCP, and for the HCB level in plasma. For the concentrations of 4-MCP and 2,3,4,6-2,3,5,6-TECP the controls had significantly higher concentrations in urine than the workers in the incineration plant. No significant differences between workers and controls were detected with respect to benzene in blood, 2,4,6-TCP and PCP in urine, and to the levels of PCP congeners in plasma. The elevated levels of hydroxypyrene, 2,4-/2,5 DCP, 2,4,5-TCP, and HCB in biological material may be related to the incineration of the waste. These elevations, however, are very small and attract attention more from the environmental than from the occupational point of view.

  10. Studies on treatment of chlorophenol-containing wastewater by microbial fuel cell

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A microbial fuel cell with 4-CP as oxidant was established to investigate the feasibility of 4-CP dechlorination in the cathodic chamber of MFC. It demonstrated good performance on electricity generation with Pmax 12.4 mW/m2 and CE 22.7%. Besides, 60 mg/L 4-CP could be completely dechlorinated in 45 h in the MFC, and 4-CP dechlorination process and electricity generation process had obvious synergistic effect.

  11. REDUCTIVE DECHLORINATION OF CHLOROPHENOLS BY A PENTACHLOROPHENOL-ACCLIMATED METHANOGENIC CONSORTIUM. (R825689C001)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  12. Photocatalytic Degradation of Nitro and Chlorophenols Using Doped and Undoped Titanium Dioxide Nanoparticles

    OpenAIRE

    Hassan Ilyas; ISHTIAQ A. QAZI; Wasim Asgar; M. Ali Awan; Zahir-ud-din Khan

    2011-01-01

    Pure and Ag-TiO2 nanoparticles were synthesized, with the metallic doping being done using the Liquid Impregnation (LI) method. The resulting nanoparticles were characterized by analytical methods such as scanning electron micrographs (SEMs), Energy Dispersive Spectroscopy (EDS), and X-ray diffraction (XRD). XRD analysis indicated that the crystallite size of TiO2 was 27 nm to 42 nm while the crystallite size of Ag-TiO2 was 11.27 nm to 42.52 nm. The photocatalytic activity of pure TiO2 and ...

  13. Adsorption of aniline, phenol, and chlorophenols on pure and modified bentonite

    Science.gov (United States)

    Yildiz, A.; Gür, A.; Ceylan, H.

    2006-11-01

    In the present study, pure bentonite and bentonite modified by HNO3, EDTA, and HDTMA are adsorbents. The changes on the surfaces of bentonite samples are studied by IR spectroscopy. The adsorption of aniline, phenol, and phenol derivatives on these adsorbents is examined by means of gas chromatography. As the result of these examinations, it is seen that the adsorption capacities of clay-organic complexes (bentonite-EDTA and bentonite-HDTMA) are higher than those of bentonite-HNO3 and pure bentonite.

  14. Removal of chlorophenols from aqueous solutions by sorption onto walnut, pistachio and hazelnut shells

    OpenAIRE

    Kuśmierek Krzysztof; Świątkowski Andrzej

    2015-01-01

    The efficiency of walnut, pistachio and hazelnut shells to remove three monochlorophenols (2-CP, 3-CP and 4-CP) from aqueous solutions has been investigated. To describe the kinetic data pseudo-first and pseudo-second order models were used. The kinetics data were fitted better into the pseudo-second order model with the coefficient of determination values greater than 0.99. The k2 values increased in the order 4-CP < 3-CP < 2-CP. Sorption was also analyzed as a function of solution concentra...

  15. A Desulfitobacterium strain isolated from human feces that does not dechlorinate chloroethenes or chlorophenols

    NARCIS (Netherlands)

    van de Pas, BA; Harmsen, HJM; Raangs, GC; de Vos, WM; Schraa, G; Stams, AJM

    2001-01-01

    An anaerobic bacterium, strain DP7, was isolated from human feces in mineral medium with formate and 0.02% yeast extract as energy and carbon source. This rod-shaped motile bacterium used pyruvate, lactate, formate, hydrogen, butyrate, and ethanol as electron donor for sulfite reduction. Other elect

  16. DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  17. Oxidation of chlorophenols catalyzed by Coprinus cinereus peroxidase with in situ production of hydrogen peroxide.

    Science.gov (United States)

    Pezzotti, Fabio; Okrasa, Krzysztof; Therisod, Michel

    2004-01-01

    Degradation of 2,6-dichlorophenol (2,6-DCP) was accomplished by oxidation catalyzed by Coprinus cinereus peroxidase. Immobilization of the enzyme in a polyacrylamide matrix enhanced DCP oxidation. Hydrogen peroxide, peroxidase's natural substrate, was produced enzymatically in situ to avoid peroxidase inactivation by its too high concentration. In the case of larger scale utilization, the method would also avoid direct handling of this hazardous reagent.

  18. Evidence against hydroxyl radical mechanism in photo-Fenton degradation of p-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper provides evidence for the degradation of organic pollutant by the photo-Fenton complex mechanism. Both the tum yield. The hydroxyl radical involved in the photo-Fenton process can also be generated from the decomposition of H2O2,photolysis of Fe3+ and degradation of hydrated Fe(Ⅵ)-complex, excepting the traditional Fenton reaction.

  19. Photocatalytic Degradation of Nitro and Chlorophenols Using Doped and Undoped Titanium Dioxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hassan Ilyas

    2011-01-01

    Full Text Available Pure and Ag-TiO2 nanoparticles were synthesized, with the metallic doping being done using the Liquid Impregnation (LI method. The resulting nanoparticles were characterized by analytical methods such as scanning electron micrographs (SEMs, Energy Dispersive Spectroscopy (EDS, and X-ray diffraction (XRD. XRD analysis indicated that the crystallite size of TiO2 was 27 nm to 42 nm while the crystallite size of Ag-TiO2 was 11.27 nm to 42.52 nm. The photocatalytic activity of pure TiO2 and silver doped TiO2 was tested by photocatalytic degradation of p-nitrophenol as a model compound. Ag-TiO2 nanoparticles exhibited better results (98% degradation as compared to pure TiO2 nanoparticles (83% degradation in 1 hour for the degradation of p-nitrophenol. Ag-TiO2 was further used for the photocatalytic degradation of 2,4-dichlorphenol (99% degradation, 2,5-dichlorophenol (98% degradation, and 2,4,6-trichlorophenol (96% degradation in 1 hour. The degree of mineralization was tested by TOC experiment indicating that 2,4-DCP was completely mineralized, while 2,5-DCP was mineralized upto 95 percent and 2,4,6-TCP upto 86 percent within a period of 2 hours.

  20. Uptake, removal, accumulation, and phytotoxicity of 4-chlorophenol in willow trees

    DEFF Research Database (Denmark)

    Ucisik, Ahmed Süheyl; Trapp, Stefan

    2008-01-01

    of implementing phytoremediation as a treatment method for 4-CP contamination was investigated. Willows were exposed to 4-CP levels ≤79.9 mg/L in hydroponic solution. The transpiration of the trees was used to determine toxic effects. Almost no inhibition of transpiration was detected at concentrations ≥15 mg...

  1. 4-chlorophenol removal from water using graphite and graphene oxides as photocatalysts

    OpenAIRE

    Bustos-Ramírez, Karina; Barrera-Díaz, Carlos Eduardo; De Icaza-Herrera, Miguel; Martínez-Hernández, Ana Laura; Natividad-Rangel, Reyna; Velasco-Santos, Carlos

    2015-01-01

    Graphite and graphene oxides have been studied amply in the last decade, due to their diverse properties and possible applications. Recently, their functionality as photocatalytic materials in water splitting was reported. Research in these materials is increasing due to their band gap values around 1.8-4 eV, and therefore, these are comparable with other photocatalysts currently used in heterogeneous photocatalytic processes. Thus, this research reports the photocatalytic effectiveness of gr...

  2. Synthesis of o-Chlorophenols via an Unexpected Nucleophilic Chlorination of Quinone Monoketals Mediated by N, N′-Dimethylhydrazine Dihydrochloride

    OpenAIRE

    Yin, Zhiwei; Zhang, Jinzhu; Wu, Jing; Green, Riana; Li, Sihan; Zheng, Shengping

    2014-01-01

    An unexpected nucleophilic chlorination of a quinone monoketal while carrying out a pyrazolidine synthesis has led to a general preparation of multisubstituted phenols. The products are obtained in good to high yields under mild conditions. The bridged pyrazolidines that were the original targets are obtained in the presence of a protic solvent.

  3. Chlorophenols degradation in soil columns inoculated with the with-rot fungus Anthracophyllum discolor Immobilized on wheat grains

    Energy Technology Data Exchange (ETDEWEB)

    Diez, M. C.; Tortella, G.; Navia, R.; Bornhardt, C.

    2009-07-01

    Anthracophyllum discolor, a white-rot fungus of southern chile, produces ligninolytic enzymes specially manganese peroxidase (MnP), and has been studied for its potential use on bioremediation of contaminated soils with chloro phenols. the main purpose of this study was to evaluate the chloro phenols degradation in soils columns inoculated with Anthracopyllum discolor immobilized on wheat grains. (Author)

  4. Non-Hodgkin's lymphoma and exposure to phenoxyherbicides, chlorophenols, fencing work, and meat works employment: a case-control study.

    OpenAIRE

    Pearce, N E; Smith, A. H.; Howard, J.K.; Sheppard, R A; Giles, H J; Teague, C A

    1986-01-01

    A previous case-control study which used the occupational information available on the New Zealand Cancer Registry found that agricultural workers were at increased risk of developing non-Hodgkin's lymphoma. The findings are now presented for the second phase of the study which entailed interviewing 83 cases of non-Hodgkin's lymphoma registered under code 202 of the International Classification of Diseases together with 168 controls with other types of cancer and 228 general population contro...

  5. Specificity of reductive dehalogenation of substituted ortho-chlorophenols by Desulfitobacterium dehalogenans JW/IU-DC1.

    OpenAIRE

    Utkin, I.; Dalton, D. D.; Wiegel, J.

    1995-01-01

    Resting cells of Desulfitobacterium dehalogenans JW/IU-DC1 growth with pyruvate and 3-chloro-4-hydroxyphenylacetate (3-Cl-4-OHPA) as the electron acceptor and inducer of dehalogenation reductively ortho-dehalogenate pentachlorophenol (PCP); tetrachlorophenols (TeCPs); the trichlorophenols 2,3,4-TCP, 2,3,6-TCP, and 2,4,6-TCP; the dichlorophenols 2,3-DCP, 2,4-DCP, and 2,6-DCP; 2,6-dichloro-4-R-phenols (2,6-DCl-4-RPs, where R is -H, -F, -Cl, -NO2, -CO2, or -COOCH3; 2-chloro-4-R-phenols (2-Cl-4-R...

  6. 31P nuclear magnetic resonance studies of effects of some chlorophenols on Escherichia coli and a pentachlorophenol-degrading bacterium.

    OpenAIRE

    Steiert, J G; Thoma, W J; Ugurbil, K; Crawford, R L

    1988-01-01

    A Flavobacterium sp. that mineralizes pentachlorophenol degrades some, but not all, of the other chlorinated phenols. Whole-cell 31P nuclear magnetic resonance was used to compare and observe transmembrane pH gradients and nucleotide pools in the Flavobacterium sp. and Escherichia coli after pentachlorophenol and 3,4,5-trichlorophenol were added to the cell suspensions. The data suggest that those chlorinated phenols which are not degraded by the Flavobacterium sp. may be resistant to degrada...

  7. CHLOROBENZENES, CHLOROPHENOLS, PAHS AND LOW CHLORINATED DIOXIN/FURAN AS POST-BOILER TOXICITY INDICATORS IN MUNICIPAL SOLID WASTE INCINERATORS

    Science.gov (United States)

    Numerous research studies have been conducted to establish indicator compounds for fast and less costly predictive monitoring of polychlorinated dibenzo-p-dioxin and furan (PCDD/F) toxic equivalent concentrations (TEQs). Many studies have shown that chlorobenzenes and chlorophen...

  8. Comparison of Reactors for Oxygen-Sensitive Reactions: Reductive Dechlorination of Chlorophenols by Vitamin B12s

    OpenAIRE

    Smith, Mark H.; Woods, Sandra L.

    1994-01-01

    Serum bottles are frequently used for studies of reductive dechlorination by vitamin B12, but reducing conditions can be maintained only for several days. This time period is inadequate for evaluating the reductive dechlorination of some slow-reacting aromatic compounds. Sealed glass ampoules maintain reducing conditions for many months, but this method has the disadvantage of disallowing subsampling of the reaction mixture. A glass serum tube was modified for these experiments which not only...

  9. Comparison of bioaugmented EGSB and GAC–FBB reactors and their combination with aerobic SBR for the abatement of chlorophenols

    OpenAIRE

    Puyol, Daniel; Monsalve, Víctor Manuel; Sanchís, Sonia; Sanz, José Luis; Fernández Mohedano, Ángel; Rodríguez, Juan José

    2015-01-01

    The biological abatement of 2,4,6-trichlorophenol (246TCP) and its chlorinated degradation byproducts using anaerobic and aerobic biological reactors coupled in series has been studied. The performance of an anaerobic fluidized bed biofilm reactor (FBBR) and expanded granular sludge bed (EGSB) reactors bioaugmented with Desulfitobacterium strains was compared within a wide range of 246TCP loading rates. The bioaugmentation of an EGSB reactor with Desulfitobacterium strains enhanced the chloro...

  10. The Seperation and Determination of o-Chlorophenol, p-Chlorophenol, m-Chlorophenol by High Performance Capillary Zone Electrophoresis%毛细管区带电泳分离测定邻、对、间氯代苯酚

    Institute of Scientific and Technical Information of China (English)

    李珺; 袁倬斌

    2001-01-01

    通过改变电泳条件,用毛细管区带电泳成功地分离了邻、对、间氯代苯酚,并检测到废水中样品的含量.研究了缓冲溶液种类、浓度、pH值、电泳电压以及内标物的选择,并得出了三种样品的标准曲线、线性范围以及加样回收率,为环境样品的监测提供了依据.

  11. Metodutveckling för analys av klorfenoler i jord samt analys av förorenad jord från ett sågverk

    OpenAIRE

    Gustavsson, Jenny

    2007-01-01

    In this final thesis, an existing method for analysis of chlorophenols (CP) in bottom sediments has been updated and adjusted for analysis of chlorophenols in soil. The covalent bonds between the chlorophenols and the soil matrix were broken through basic hydrolysis and the chlorophenols were then separated from the water phase through addition of sulphuric acid followed by ether extraction. The chromatography was improved through extractive acetylation of the chlorophenols. The updated metho...

  12. 3种氯酚化合物对大型溞的联合毒性%Joint Toxicity of Three Chlorophenols to Daphnia magna

    Institute of Scientific and Technical Information of China (English)

    张亚辉; 曹莹; 王一喆; 刘征涛

    2011-01-01

    氯酚类化合物是我国水体中广泛存在的一类优先控制污染物,以大型溞(Daphnia magna)为试验生物,测定了2,4-二氯酚、2,4,6-三氯酚和五氯酚对大型溞的48 h致死的单一毒性和联合毒性.基于单一氯酚化合物的浓度-效应曲线,运用浓度加和(CA)与独立作用(IA)2个模型对2种等毒性浓度比的混合物(Mix-LC50和Mix-LC1)的联合毒性进行预测.通过氯酚混合物的观测数据的95%置信区间与CA和IA模型预测的浓度-效应曲线进行比较分析,结果表明,CA预测曲线与Mix-LC50和Mix-LC1这2种混合物的95%置信区间相近,而与IA的预测相差较大.以模型偏差率(MDR)表示CA或者IA预测效应浓度和观测值之间的偏差,在不同效应水平下CA对2种混合物的MDR值均小于1.5,说明CA能够预测3种氯酚化合物对大型溞的联合毒性.%Chbrophenol chemicals are a kind of priority pollutants and widely exist in waters of China. The individual toxicrty and the joint toxicity of 2,4-dichbrophenol, 2,4,6-trichlorophenol and pentachbrophenol to Daphnia magna were investigated. Based on the concentration-response curves of every single chbrophenol, two models including concentration addition (CA) and independent action (IA) were empbyed to predict the joint toxic ity of two mixtures in equivalent toxic concentration ratios, I.e., Mix-LC50 and Mix-LC,. The concentration-response curves predicted by CA and IA were compared with the 95% observed confidence intervals calculated from the experimental data. The results demonstrated that the CA curves almost agreed with the 95% observed confidence intervals, while the IA curves departed from the 95% observed confidence intervals. The model deviation ratio (MDR) which is defined as the deviation between the effect concentration predicted by CA and the observed data, did not exceed the factor of 1.5 at different effect levels of the two mixtures. It was demonstrated that CA could be employed to predict the joint toxic ity of the mixtures of the three chbrophenols to Daphnia magna .

  13. Plasma dioxin levels and cause-specific mortality in an occupational cohort of workers exposed to chlorophenoxy herbicides, chlorophenols and contaminants

    NARCIS (Netherlands)

    Boers, D.; Portengen, L.; Turner, W.E.; Bueno-de-Mesquita, H.B.; Heederik, D.; Vermeulen, R.

    2012-01-01

    BACKGROUND: We recently reported increased risks for all cancers and urinary cancers in workers exposed to chlorophenoxy herbicides using data from the Dutch herbicide cohort study. These risks could not be linked to the qualitative exposure proxies available. Here, we re-investigate exposure-respon

  14. UV photolysis of 4-iodo-, 4-bromo-, and 4-chlorophenol: Competition between C-Y (Y = halogen) and O-H bond fission

    Science.gov (United States)

    Sage, Alan G.; Oliver, Thomas A. A.; King, Graeme A.; Murdock, Daniel; Harvey, Jeremy N.; Ashfold, Michael N. R.

    2013-04-01

    The wavelength dependences of C-Y and O-H bond fission following ultraviolet photoexcitation of 4-halophenols (4-YPhOH) have been investigated using a combination of velocity map imaging, H Rydberg atom photofragment translational spectroscopy, and high level spin-orbit resolved electronic structure calculations, revealing a systematic evolution in fragmentation behaviour across the series Y = I, Br, Cl (and F). All undergo O-H bond fission following excitation at wavelengths λ ≲ 240 nm, on repulsive ((n/π)σ*) potential energy surfaces (PESs), yielding fast H atoms with mean kinetic energies ˜11 000 cm-1. For Y = I and Br, this process occurs in competition with prompt C-I and C-Br bond cleavage on another (n/π)σ* PES, but no Cl/Cl* products unambiguously attributable to one photon induced C-Cl bond fission are observed from 4-ClPhOH. Differences in fragmentation behaviour at longer excitation wavelengths are more marked. Prompt C-I bond fission is observed following excitation of 4-IPhOH at all λ ≤ 330 nm; the wavelength dependent trends in I/I* product branching ratio, kinetic energy release, and recoil anisotropy suggest that (with regard to C-I bond fission) 4-IPhOH behaves like a mildly perturbed iodobenzene. Br atoms are observed when exciting 4-BrPhOH at long wavelengths also, but their velocity distributions suggest that dissociation occurs after internal conversion to the ground state. O-H bond fission, by tunnelling (as in phenol), is observed only in the cases of 4-FPhOH and, more weakly, 4-ClPhOH. These observed differences in behaviour can be understood given due recognition of (i) the differences in the vertical excitation energies of the C-Y centred (n/π)σ* potentials across the series Y = I < Br < Cl and the concomitant reduction in C-Y bond strength, cf. that of the rival O-H bond, and (ii) the much increased spin-orbit coupling in, particularly, 4-IPhOH. The present results provide (another) reminder of the risks inherent in extrapolating photochemical behaviour measured for one molecule at one wavelength to other (related) molecules and to other excitation energies.

  15. Simultaneous removal of Cr(VI) and 4-chlorophenol through photocatalysis by a novel anatase/titanate nanosheet composite: Synergetic promotion effect and autosynchronous doping.

    Science.gov (United States)

    Liu, Wen; Sun, Weiling; Borthwick, Alistair G L; Wang, Ting; Li, Fan; Guan, Yidong

    2016-11-01

    Clean-up of wastewaters with coexisting heavy metals and organic contaminants is a huge issue worldwide. In this study, a novel anatase/titanate nanosheet composite material (labeled as TNS) synthesized through a one-step hydrothermal reaction was demonstrated to achieve the goal of simultaneous removal of Cr(VI) and 4-cholophenol (4-CP) from water. TEM and XRD analyses indicated the TNS was a nano-composite of anatase and titanate, with anatase acting as the primary photocatalysis center and titanate as the main adsorption site. Enhanced photocatalytic removal of co-existent Cr(VI) and 4-CP was observed in binary systems, with apparent rate constants (k1) for photocatalytic reactions of Cr(VI) and 4-CP about 3.1 and 2.6 times of that for single systems. In addition, over 99% of Cr(VI) and 4-CP was removed within 120min through photocatalysis by TNS at pH 7 in the binary system. Mechanisms for enhanced photocatalytic efficiency in the binary system are identified as: (1) a synergetic effect on the photo-reduction of Cr(VI) and photo-oxidation of 4-CP due to efficient separation of electron-hole pairs, and (2) autosynchronous doping because of reduced Cr(III) adsorption onto TNS. Furthermore, TNS could be efficiently reused after a simple acid-base treatment.

  16. Simultaneous removal of Cr(VI) and 4-chlorophenol through photocatalysis by a novel anatase/titanate nanosheet composite: Synergetic promotion effect and autosynchronous doping.

    Science.gov (United States)

    Liu, Wen; Sun, Weiling; Borthwick, Alistair G L; Wang, Ting; Li, Fan; Guan, Yidong

    2016-11-01

    Clean-up of wastewaters with coexisting heavy metals and organic contaminants is a huge issue worldwide. In this study, a novel anatase/titanate nanosheet composite material (labeled as TNS) synthesized through a one-step hydrothermal reaction was demonstrated to achieve the goal of simultaneous removal of Cr(VI) and 4-cholophenol (4-CP) from water. TEM and XRD analyses indicated the TNS was a nano-composite of anatase and titanate, with anatase acting as the primary photocatalysis center and titanate as the main adsorption site. Enhanced photocatalytic removal of co-existent Cr(VI) and 4-CP was observed in binary systems, with apparent rate constants (k1) for photocatalytic reactions of Cr(VI) and 4-CP about 3.1 and 2.6 times of that for single systems. In addition, over 99% of Cr(VI) and 4-CP was removed within 120min through photocatalysis by TNS at pH 7 in the binary system. Mechanisms for enhanced photocatalytic efficiency in the binary system are identified as: (1) a synergetic effect on the photo-reduction of Cr(VI) and photo-oxidation of 4-CP due to efficient separation of electron-hole pairs, and (2) autosynchronous doping because of reduced Cr(III) adsorption onto TNS. Furthermore, TNS could be efficiently reused after a simple acid-base treatment. PMID:27318735

  17. Dechlorination by combined electrochemical reduction and oxidation*

    OpenAIRE

    Cong, Yan-qing; Wu, Zu-cheng; Tan, Tian-en

    2005-01-01

    Chlorophenols are typical priority pollutants listed by USEPA (U.S. Environmental Protection Agency). The removal of chlorophenol could be carried out by a combination of electrochemical reduction and oxidation method. Results showed that it was feasible to degrade contaminants containing chlorine atoms by electrochemical reduction to form phenol, which was further degraded on the anode by electrochemical oxidation. Chlorophenol removal rate was more than 90% by the combined electrochemical r...

  18. 塩化ベンゼンの生体膜に対する作用 第Ⅳ報 分離正常ラット肝ミトコンドリアにおける塩化ベンゼン及び塩化フェノールの作用の比較

    OpenAIRE

    森, 孝昭

    1986-01-01

    A comparative study on the effect of chlorobenzenes and chlorophenols on mitochondrial membranes was conducted. An increase in chlorine residue from both chlorobenzenes and chlorophenols caused a decrease in respiratory control index (RCI). Chlorophenols acted on biomembranes at a lower concentration than chlorobenzenes. The compounds decreased RCI by increasing state 4 respiration and decreasing state 3 respiration. As the number of chlorine atoms on chlorobenzenes increased, state 3 respira...

  19. Effective Synthesis of Sulfate Metabolites of Chlorinated Phenols

    OpenAIRE

    Lehmler, Hans-Joachim; He, Xianran; Li, Xueshu; Duffel, Michael W.; Parkin, Sean

    2013-01-01

    Chlorophenols are an important class of persistent environmental contaminants and have been implicated in a range of adverse health effects, including cancer. They are readily conjugated and excreted as the corresponding glucuronides and sulfates in the urine of humans and other species. Here we report the synthesis and characterization of a series of ten chlorophenol sulfates by sulfation of the corresponding chlorophenols with 2,2,2-trichloroethyl (TCE) chlorosulfate using N,N-dimethylamino...

  20. Rhamnolipids as active protective agents for microorganisms against toxic substances

    OpenAIRE

    Marta Woźniak; Roman Marecik; Łukasz Ławniczak; Łukasz Chrzanowski

    2012-01-01

    The presence of microbial biosurfactants decreases the toxicity of chlorophenols towards Pseudomonas putida 2A cells. The rhamnolipid-originating micelles selectively entrapped chlorophenol molecules, which resulted in their lower bioavailability to microbial cells. It was observed that the effective concentrations causing 50% growth inhibition increased by 0.5, 0.35 and 0.15 for phenol, 4-chlorophenol and 2.4-dichlorophenol, accordingly. The application of surfactants as protective agents...

  1. Aqueous solubilities of phenol derivatives by conductivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Achard, C.; Jaoui, M.; Schwing, M.; Rogalski, M. [Univ. de Metz (France). Lab. de Thermodynamique et d`Analyse Chimique

    1996-05-01

    The aqueous solubilities of five chlorophenols and three nitrophenols were measured by conductimetry at temperatures between 15 and 48C. The solubilities of 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, 2-nitrophenol, 4-nitrophenol, and 2,4-dinitrophenol were studied. Automatic conductivity measurements allow the determination of the solute concentration and, hence, the determination of the solubility. Emulsion formation can also be followed. Results obtained are in good agreement with literature values.

  2. 天然锰矿催化臭氧氧化降解水中4-氯酚的研究%Treatment of 4-chlorophenol in aqueous by catalyzed ozonation with manganese ore

    Institute of Scientific and Technical Information of China (English)

    李海燕; 施银桃; 夏东升; 曾庆福

    2004-01-01

    以天然锰矿为金属催化剂,研究了锰矿催化臭氧氧化水中4-氯酚的降解效果.采用毛细管电泳方法及色质联用技术,分别对反应的中间产物和终产物进行了分析.推测了锰矿催化臭氧氧化水中4-氯酚的降解反应机理可能为:锰矿的吸附氧化与锰矿生成的Mn2+催化臭氧分解,产生更多高活性的羟基自由基,从而提高了臭氧的氧化能力.

  3. 高压脉冲放电与臭氧氧化联用降解水中对氯苯酚%Degradation of 4-Chlorophenol in Aqueous Solution by High-voltage Pulsed Discharge-Ozone Technology

    Institute of Scientific and Technical Information of China (English)

    文岳中; 姜玄珍; 刘维屏

    2002-01-01

    研究高压脉冲放电与臭氧协同降解水中对氯苯酚影响因素的结果表明,250mg/L对氯苯酚处理30min后降解率达96%.臭氧浓度、自由基捕获剂以及电极之间的距离均可影响对氯苯酚的降解率.增加臭氧浓度及降低电极之间的距离,提高了对氯苯酚的降解率;加入自由基捕获剂,降低了对氯苯酚的降解率.

  4. UV-Fenton体系氧化降解邻氯苯酚废水反应动力学研究%Kinetic study of o-chlorophenol wastewater treatment by UV-Fenton oxidation

    Institute of Scientific and Technical Information of China (English)

    熊思江; 刘琼玉; 张如月; 王芬

    2007-01-01

    采用UV-Fenton高级氧化技术对邻氯苯酚废水进行了处理研究.从反应速率系数着手探讨了污染物初始浓度、双氧水加入量、亚铁离子浓度及pH值对反应降解速率的影响.用半衰期法对邻氯苯酚的反应级数进行了探讨,确定其在UV-Fenton体系降解过程中的表观反应级数为3/2,并初步建立了邻氯苯酚UV-Fenton降解的动力学模型.

  5. Influence of the particle size of activated mineral carbon on the phenol and chlorophenol adsorption; Influencia del tamano de particula de carbon mineral activado sobre la adsorcion de fenol y clorofenol

    Energy Technology Data Exchange (ETDEWEB)

    Garcia M, A

    2001-07-01

    Water pollution by phenolic compounds is a problem that requires a solution since these phenolic compounds are not completely biodegradable, they accumulate through the food chains and they are quite toxic when enter in contact with living organisms. In human beings, ingestion or contact of the skin with this type of compounds produces irritation and damages mainly to the liver and kidneys. In fact, the Environmental Protection Agency of the United States (EPA assigned nine phenolic compounds among the 275 most toxic substances in 1991. Phenols are found in wastewater from agriculture and industry, because phenolic compounds are used as pesticides and in diverse industrial activities. The treatment of this type of water is not simple because they are generally composed of a mixture of residuals with different chemical nature A useful method for the removal of phenols is the adsorption by activated carbon, since this material has a great surface area and it can be regenerated. The adsorption process depends, among other factors, on the activated carbon characteristics. When they are modified, their capacity to remove pollutants from the water changes. The effect of activated carbon particle size on the removal of phenolic compounds has not been completely studied. Therefore, the aim of this work was to determine the influence of the mineral activated carbon particle size on the phenol and 4-chloro phenol adsorption in aqueous solution, on adsorption column system. The results of the present work indicate that the mineral activated carbon particle size has a very important influence on the adsorption of phenol and 4-chloro phenol. When the particles were smaller, the retention quantities of phenol and 4-chloro phenol increased. This behavior was related to the particle characteristics of the mineral activated carbon such as surface area and pore volume, while other factors such as elementary composition of the activated carbon did not influence the adsorption process in an important way. Finally, when the particle size decreased, the saturation percentage decreased as well as the adsorption capacity increased for the studied phenolic compounds. (Author)

  6. Adsorción de Fenol y 3-Cloro Fenol sobre Carbones Activados mediante Calorimetría de Inmersión Adsorption of Phenol and 3-Chlorophenol n Activated Carbons using Immersion Calorimetry

    OpenAIRE

    Moreno-Piraján, Juan C.; Luisa F Navarrete; Liliana Giraldo; Vanessa García

    2007-01-01

    Se ha determinado la entalpía de inmersión de cinco muestras de carbón activado, obtenidas a partir de diferentes materiales lignocelulósicos, con diferente grado de activación en disoluciones acuosas de fenol y 3-cloro fenol con el fin de caracterizar la interacción sólido-disolución acuosa, obteniéndose valores entre 6.80 y 13.9 Jg-1. Se determinó también, las entalpías de inmersión de estos carbones activados en disoluciones de NaOH y HCl 0.1 M, obteniéndose los más altos valores de la ent...

  7. 高压脉冲放电降解水溶液中4-氯酚过程的数学模型(Ⅱ)鼓泡过程中臭氧传质增强因子E与4-氯酚浓度的关系%Mathematical model of 4-chlorophenol degradation in aqueous solution by pulsed high-voltage discharge(Ⅱ)Relationship between enhancement factor of ozone mass transfer and 4-chlorophenol concentration

    Institute of Scientific and Technical Information of China (English)

    陈银生; 张新胜; 戴迎春; 袁渭康

    2005-01-01

    臭氧从气相传质到废水溶液中并与其中的有机污染物发生氧化还原反应是一个含有化学反应增强的臭氧吸收过程.在酸性废水中主要发生臭氧与4-氯酚分子和4-氯酚盐离子的反应,而臭氧在水溶液中分解形成的羟基自由基的氧化作用可以忽略.提出了由于发生化学反应而形成的臭氧传质增强因子E与废水中有机物浓度[PCP]的定量关系的表达式.

  8. Biodegradation of Complex Bacteria on Phenolic Derivatives in River Water

    Institute of Scientific and Technical Information of China (English)

    GUANG-HUA LU; CHAO WANG; ZHE SUN

    2009-01-01

    Objective To isolate, incubate, and identify 4-chlorophenol-degrading complex bacteria, determine the tolerance of these bacteria to phenolic derivatives and study their synergetic metabolism as well as the aboriginal microbes and co-metabolic degradation of mixed chlorophenols in river water. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicants. Biodegradability of phenolic derivatives was determined by adding 4-chlorophenol-degrading bacteria in river water. Results The complex bacteria were identified as Mycopiana, Alcaligenes, Pseudvmonas, and Flavobacterium. The domesticated complex bacteria were more tolerant to phenolic derivatives than the aboriginal bacteria from Qinhuai River. The biodegradability of chlorophenols, dihydroxybenzenes and nitrophenols under various aquatic conditions was determined and compared. The complex bacteria exhibited a higher metabolic efficiency on chemicals than the aboriginal microbes, and the final removal rate of phenolic derivatives was increased at least by 55% when the complex bacteria were added into river water. The metabolic relationship between dominant mixed bacteria and river bacteria was studied. Conclusion The complex bacteria domesticated by 4-chlorophenol can grow and be metabolized to take other chlorophenols, dihydroxybenzenes and nitrophenols as the sole carbon and energy source. There is a synergetic metabolism of most compounds between the aboriginal microbes in river water and the domesticated complex bacteria. 4-chlorophenol-degrading bacteria can co-metabolize various chlorophenols in river water.

  9. Dechlorination by combined electrochemical reduction and oxidation

    Institute of Scientific and Technical Information of China (English)

    CONG Yan-qing; WU Zu-cheng; TAN Tian-en

    2005-01-01

    Chlorophenols are typical priority pollutants listed by USEPA (U.S. Environmental Protection Agency). The removal of chlorophenol could be carried out by a combination of electrochemical reduction and oxidation method. Results showed that it was feasible to degrade contaminants containing chlorine atoms by electrochemical reduction to form phenol, which was further degraded on the anode by electrochemical oxidation. Chlorophenol removal rate was more than 90% by the combined electrochemical reduction and oxidation at current of 6 mA and pH 6. The hydrogen atom is a powerful reducing agent that reductively dechlorinates chlorophenols. The instantaneous current efficiency was calculated and the results indicated that cathodic reduction was the main contributor to the degradation of chlorophenol.

  10. Rhamnolipids as active protective agents for microorganisms against toxic substances

    Directory of Open Access Journals (Sweden)

    Marta Woźniak

    2012-12-01

    Full Text Available The presence of microbial biosurfactants decreases the toxicity of chlorophenols towards Pseudomonas putida 2A cells. The rhamnolipid-originating micelles selectively entrapped chlorophenol molecules, which resulted in their lower bioavailability to microbial cells. It was observed that the effective concentrations causing 50% growth inhibition increased by 0.5, 0.35 and 0.15 for phenol, 4-chlorophenol and 2.4-dichlorophenol, accordingly. The application of surfactants as protective agents for microorganisms brings about new possibilities of using this phenomenon in bioremediation techniques.

  11. Voorspelling van de biodegradatie van gesubstitueerde monocyclische aromaten in de bodem

    NARCIS (Netherlands)

    Verschoor AJ

    1993-01-01

    The project "Prediction of the biodegradation of substituted monocyclic aromatic compounds in soils" has resulted in the development of the model SPAR (Soil Properties Activity Relationship), which describes the initial and maximal biodegradation rate of chlorophenols and chloroanilines in

  12. ANAEROBIC/AEROBIC BIODEGRADATION OF PENTACHLOROPHENOL USING GAC FLUIDIXED BED REACTORS: OPTIMIZATION OF THE EMPTY BED CONTACT TIME

    Science.gov (United States)

    An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to approximately equimolar concentrations (>99%) of chlorophenol (CP) in a granular activa...

  13. Uses of peroxide on the formation of chlorinated phenolics by gas chromatography technique in nonwood pulps to reduce toxicity in paper manufacturing

    Science.gov (United States)

    Prakash, Divya; Kumar, S.; Tomar, Neeraj

    2016-05-01

    ECF technology has been established itself as the most preferred process worldwide. Peroxide addition minimizes the effluent color. The study deals with the bleaching of Bamboo and Jute Cady pulps with chlorine and peroxide treatment and identification of various chlorophenolics compounds. The results show that quantity of the total chlorophenolic compounds formed decreases up to 54% in total chlorophenolic compound in the CEH effluent and the COD and color values are reduced by 35% and 33% respectively as E stage is changed to Ep stage in Bamboo pulp. And there is a reduction of 52% in total chlorophenolic compound in the CEH effluent when E stage is changed to Ep. and the COD and color values are reduced by 30% and 33% respectively as E stage is changed to Ep stage in Jute Cady pulp

  14. Effect of electron beam irradiation on the degradation of monochlorophenols in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    ADELEKE Olukunle Francis; ZHOU Rui-min; Zu Jian-hua; Ekoko Bakambo Gracien

    2005-01-01

    Electron beam was successfully used for the degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) in aqueous solutions in this research. The effect of radiation dose on substrate degradation and dechlorination of solutions with concentration of 50 mg/L was investigated. The effect of initial concentration, pH and presence of oxygen was also investigated. The concentration of 2-CP and 4-CP remaining in solution after irradiation were measured by HPLC. The results showed that increased radiation dose led to increased degradation of the chlorophenols and increased Cl- yield. Deaeration was also found to significantly increase the rate of degradation of chlorophenols in water while degradation and dechlorination under alkaline condition was lower than at low to neutral pH.

  15. Spectrum of the Reductive Dehalogenation Activity of Desulfitobacterium frappieri PCP-1

    OpenAIRE

    Dennie, D.; Gladu, I.; Lépine, F; Villemur, R; Bisaillon, J.-G.; Beaudet, R

    1998-01-01

    Desulfitobacterium frappieri PCP-1 was induced for ortho- and para-dechlorinating activities by different chlorophenols. Dehalogenation rates ranging from 25 to 1,158 nmol/min/mg of cell protein were observed according to the chlorophenol tested and the position of the chlorine removed. D. frappieri shows a broad substrate specificity; in addition to tetrachloroethylene and pentachloropyridine, strain PCP-1 can dehalogenate at ortho, meta, and para positions a large variety of aromatic molecu...

  16. Removing 3,5-Dichlorophenol from Wastewater by Alternative Adsorbents

    OpenAIRE

    Kobetičová Hana; Galbičková Blanka; Ševčíková Janka; Soldán Maroš

    2014-01-01

    The main objective of this paper is to evaluate an efficiency of 3,5 - dichlorophenol removal from wastewater by using alternative adsorbents. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and also atoms of chlorine. Chlorophenols may have a huge isomere variety that means there are differences in their chemical and physical properties. Due to their toxicity it is necessary to remove them from waste water and in this paper an alternative way of such process is de...

  17. Treatment of phenolic wastewater in suspended and fixed bed bioreactors

    OpenAIRE

    Bajaj, Mini

    2009-01-01

    Phenol and chlorophenols are among the most important class of raw materials in chemical industry. These compounds also list among priority pollutants. The main problem in treating phenol or chlorophenol containing wastewater is the toxicity it exerts to the microbial flora in biological treatment plants. This may lead to partial or complete treatment plant failure, when the microbial flora is not adapted to phenol concentrations in the influent. The purpose of this thesis was to adapt the mi...

  18. Improved Degradation of Monochlorophenols by a Constructed Strain

    OpenAIRE

    Schwien, Uwe; Schmidt, Eberhard

    1982-01-01

    Pseudomonas sp. strain B13, a strain able to degrade 3-chlorobenzoate and, after prolonged adaptation (40 days), 4-chlorophenol, could transfer the ability to degrade chlorocatechols to a recipient, Alcaligenes sp. strain A7, which is able to grow with benzoate and phenol. Representative transconjugants, such as Alcaligenes sp. strain A7-2, were able to utilize all three isomeric chlorophenols; this property was not possessed by the donor or the recipient. The ability to grow readily with 4-c...

  19. Evaluation of a mitochondrial test for the determination of chemical toxicity

    OpenAIRE

    Shannon, Robert David

    1988-01-01

    The feasibility of using rat liver mitochondria respiratory parameters as a short-term toxicity test was investigated. Mitochondrial fractions were exposed to six concentrations of five chlorophenols. Respiratory parameters were measured and compared to control experiments. The toxicity of the chlorophenos, measured by the 50% uncoupling concentration (UC50), increased with increasing chloro substitution. The UC50 values for the five chlorophenols were compared to six phy...

  20. Možnosti stanovení těkavých látek při výrobě piva

    OpenAIRE

    Rozsypalová, Markéta

    2015-01-01

    The thesis discusses the possibilities of determination of chlorophenols in beer. A review of literature describes the complex properties of chlorinated phenols. Summarizes their physical, chemical and toxicological properties and characterizes their possible inputs into the environment. In the experimental part is the main theme of the determination of chlorophenols in samples of small breweries and beers called as home brew. These are various types of beer, in which the amount of chlorophen...

  1. Inhibition of β-galactosidase and α-glucosidase synthesis in petroleum refinery effluent bacteria by phenolic compounds

    OpenAIRE

    Gideon C. Okpokwasili; Christian O. Nweke

    2011-01-01

    Inhibition of α-glucosidase (EC 3.2.1.20) and β-galactosidase (EC 3.2.1.23) biosynthesis by phenolic compounds (phenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol) in Escherichia coli, Bacillus and Pseudomonas species isolated from petroleum refinery wastewater was assessed. At sufficient concentrations, phenols inhibited the induction of α-glucosidase and β-galactosidase. The patterns of these toxic effects can be mathematically described with logistic and sigmoid d...

  2. Kinetic and isotherm studies of adsorption and biosorption processes in the removal of phenolic compounds from aqueous solutions: comparative study

    OpenAIRE

    Gholizadeh, Abdolmajid; Kermani, Majid; Gholami, Mitra; Farzadkia, Mehdi

    2013-01-01

    The phenolic compounds are known by their carcinogenicity and high toxicity as well as creating unpleasant taste and odor in water resources. The present study develops a cost-effective technology for the treatment of water contaminated with phenolic compounds, including Phenol (Ph), 2-chlorophenol (2-CP), and 4-chlorophenol (4-CP). So, two sorbents, rice bran ash (RBA) and biomass of brown algae, Cystoseiraindica, were used and results were compared with the commercially granular activated c...

  3. Surface catalyzed chlorobenzene transformation reactions in post-combustion zone

    Energy Technology Data Exchange (ETDEWEB)

    Nakka, H.; Fullana, A.; Sidhu, S. [Dayton Univ., OH (United States). Environmental Engineering

    2004-09-15

    It has been shown that condensation of chlorophenols is a major pathway for the formation of polychlorinated dibenzodioxins and furans (PCDD/F) but the role of other compounds like chlorobenzenes is not clear. It has been shown that chlorobenzenes have lower PCDD/F formation rates than phenols. Born et al. showed that when a mixture of chlorobenzene and chlorophenol was passed over fly ash bed, chlorophenol was completely converted but chlorobenzene was unaffected. This shows that chlorobenzenes are inert with respect to oxidation and oxychlorination. However, it should be noted that experiments of Born et al. were focused on fate of chlorophenol and only in the first experiment they passed a mixture of chlorophenol and chlorobenzene and found chlorobenzene to be inactive. They did not use HCl in the experiments in which chlorobenzene was used as reactant over fly ash. Altwicker et al. investigating the role of chlorobenzenes in de novo PCDD/F formation reactions observed that presence of chlorobenzenes leads to decline in PCCD/F yields over fly ash. Results of Altwicker et al. indicate that chlorobenzenes are not precursors of PCDD/Fs. However, chlorobenzenes are regularly used as indicators for continous indirect monitoring of PCDD/F emissions. Blumenstock et al. observed that lower chlorinated benzenes show a high correlation with the international toxicity equivalent (I-TEQ) value of PCDD/F, which implies that chlorobenzene and PCDD/F formation are connected in some way. Chlorobenzenes may not have a major role in the formation of PCDD/F, however, it can form phenol/chlorophenols in presences of a chlorine source. Procaccini et al. showed conversion of benzene to chlorobenzene and chlorophenol by reaction with chlorine radicals in the cool zone of a plug-flow combustor.

  4. Estudio clínico comparativo entre colutorio de p-clorofenol y peróxido de hidrógeno con colutorio de clorhexidina al 0.12% en el crecimiento de placa microbiana y gingivitis Mouthwash comparative study between p-chlorophenol and hydrogen peroxide with chlorhexidine mouthwash 0.12% in the growth of microbial plaque and gingivitis

    OpenAIRE

    PD Jaña; LI Yévenes; AS Rivera

    2010-01-01

    Se formuló un colutorio a base de p-clorofenol alcanforado y peróxido de hidrógeno, y considerando que no se disponían de antecedentes de eficacia y seguridad del colutorio, se realizó un ensayo clínico para medirlas utilizando un modelo de formación de placa microbiana y gingivitis en un período de cuatro días, como control positivo se uso un colutorio de clorhexidina al 0.12%. Participaron 26 sujetos en un estudio doble ciego cruzado y con distribución aleatoria. El colutorio en base a p-cl...

  5. Mathematical model of 4-chlorophenol degradation in aqueous solution by pulsed high-voltage discharge (Ⅰ) Calculation of formation rate of ozone due to oxygen discharge%高压脉冲放电降解水溶液中4-氯酚过程的数学模型(Ⅰ)氧气放电形成臭氧的速率计算

    Institute of Scientific and Technical Information of China (English)

    陈银生; 张新胜; 李云飞; 戴迎春; 袁渭康

    2005-01-01

    采用电子碰撞理论计算了点-面式高压脉冲电晕放电过程中的臭氧产生速率.研究发现,臭氧形成速率是电场中能量大于等于6.0eV的电子形成速率的2倍.脉冲电压峰值和放电频率与臭氧生成速率均几乎有线性关系.放电电极直径比电极间距对臭氧生成速率的影响更加显著.

  6. Kinetics of P-Chlorophenol Wastewater Treatment by UV/H2O2 Oxidation%UV/H2O2光化学氧化降解对氯苯酚废水的反应动力学

    Institute of Scientific and Technical Information of China (English)

    陈琳; 杜瑛珣; 雷乐成

    2003-01-01

    研究了UV/H2O2体系降解对氯苯酚废水的过程及动力学结果表明,反应降解速率与双氧水加入量、污染物初始浓度及载气种类有关.在双氧水理论投加量一半的情况下,通入氧气或空气,总酚的降解率可达到96%,CODCr去除率接近50%.反应体系加入载气,显著影响污染物的去除率.在本实验中,总酚降解为拟一级反应.

  7. Dechlorination progress of chlorinated organic pollutants degraded by use of ionizing radiation in aqueous solutions

    International Nuclear Information System (INIS)

    Kinetics and mechanisms of dechlorination of chlorinated organic pollutants induced by ionizing radiation were described in this article. The progress on the dechlorination of chlorophenols, polychlorinated biphenyl, trichloroethylene, and perchloroethylene involved in radiolysis was also reviewed. In oxidative condition, hydroxyl radical (·OH) would attack chlorophenol to form ·OH-adducts, which could be dechlorinated gradually. However, chlorophenol can be directly reduced by hydrated electron (eaq-) to release Cl-. It was found that radiolytic degradation of polychlorinated biphenyls in organic solvent would release chlorine atoms gradually by chain reactions and the final products were Cl- and biphenyl. Trichloroethylene and tetrachloroethylene mainly reacted with ·OH with the final products of CO2, HCOOH and HCI. As conclusion, the reductive dechlorination of chlorinated organic pollutants possesses advantages of high degradation efficiency, simple products and relatively low radiation dose compared with the oxidation methods. (authors)

  8. Evaluación de un electrodo de carbón vítreo modificado con Zeolita tipo “A” en la adsorción de 2-clorofenol

    Directory of Open Access Journals (Sweden)

    Aurora Molina

    2009-10-01

    Full Text Available Glassy carbon electrodes modified with Zeolite “A” were studied in order to evidence the adsorption of 2-chlorophenol. Synthesis of zeolite was undertaken by a hydrothermal method using calcined kaolin as raw material. The zeolite was first exchanged with calcium ions. Then, it was modified with the cationic surfactant CTAB (cetyl trimethyl ammonium bromide or the non-ionic surfactant Triton X-100 (t-octylphenoxy-polyethoxyethanol. Adsorption of 2-chlorophenol was evaluated by cyclic voltammetry, once it was adsorbed onto the modified electrode. Electrochemical results indicated that the films surfactant-zeolites were able to adsorb the 2-chlorophenol from an aqueous alkaline medium. The best results were achieved when the cationic surfactant CTAB was used. The importance of electrode surface cleaning to guarantee the complete adherence between the vitreous carbon and the modified surfactant zeolite was determinated. Polishing and cleaning processes depend on the type of surfactant used.

  9. Catalytic dechlorination of o-cllorophenol by nanoscale Pd/Fe

    Institute of Scientific and Technical Information of China (English)

    WEI Jian-jun; XU Xin-hua; WANG Da-hui

    2004-01-01

    Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the laboratory for treatment of o-chlorophenol. Most of the nanoscale particles are in the size range of 20-100 nm. BET specific surface area of the nanoscale Pd/Fe particles is 12.4 m2/g. In comparison, a commercially available Fe powder( <100 mesh) has a specific surface area of just 0.49 m2/g. Batch experiments demonstrated that the nanoscale Pd/Fe bimetallic particles can effectively dechlorinate o-chlorophenol. Dechlorination efficiency is affected by the mass fraction of Pd in the bimetal, nanoscale Pd/Fe mass concentration and mixing intensity.

  10. Iron humate as a multifunctional sorbent for inorganic and organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Janos, P. [University of Jan Evangelista Purkyne, Usti Nad Labem (Czech Republic). Faculty of Environment

    2005-07-01

    Iron humate, produced from low-rank brown coal, can be used as an effective sorbent for substances as different as metal ions and low-polarity organic compounds (chlorophenols). The sorption capacities ranged from 0.024 to 0.324 mmol g{sup -1} for metal ions and from 0.016 to 0.037 mmol g{sup -1} for chlorophenols. Evidently, different mechanisms are responsible for the sorption of various chemical pollutants from aqueous solutions. Multimode sorption mechanisms play an important role also in the sorption of ionic compounds such as basic dyes in the presence of oppositely charged surfactants.

  11. gamma-radiolysis and pulse radiolysis of aqueous 4-chloroanisole

    DEFF Research Database (Denmark)

    Quint, R.M.; Park, H.R.; Krajnik, P.;

    1996-01-01

    after T-radiolysis in dependence of dose (100-600 Gy) are given for N2O-, air-, oxygen- and argon saturated neutral aqueous solutions. In conditions favoring the OH radical oxidation 4-chlorophenol, 4-methoxyphenol, 5-chloro-2-methoxyphenol and 2-chloro-5-methoxyphenol were determined as final products...... quantitatively to the degradation of the substrate. In the presence of air or solutions saturated with pure oxygen predominantly hydroquinone. 4-chlorophenol and muconic acids are formed and the material balance is similar to 50%. The efficient dechlorination (similar to 66% of the decomposed 4-CIAn) as well as...

  12. Impact of phenolic substrate and growth temperature on the arthrobacter chlorophenolicus proteome

    Energy Technology Data Exchange (ETDEWEB)

    Unell, Maria; Abraham, Paul E.; Shah, Manesh; Zhang, Bing; Ruckert, Christian; VerBerkmoes, Nathan C.; Jansson, Janet K.

    2009-02-15

    We compared the Arthrobacter chlorophenolicus proteome during growth on 4-chlorophenol, 4-nitrophenol or phenol at 5 C and 28 C; both for the wild type and a mutant strain with mass spectrometry based proteomics. A label free workflow employing spectral counting identified 3749 proteins across all growth conditions, representing over 70% of the predicted genome and 739 of these proteins form the core proteome. Statistically significant differences were found in the proteomes of cells grown under different conditions including differentiation of hundreds of unknown proteins. The 4-chlorophenol-degradation pathway was confirmed, but not that for phenol.

  13. Wet oxidation processes for water pollution remediation

    OpenAIRE

    García Molina, Verónica

    2006-01-01

    [eng] The main objective of this work was to test the efficiency of wet oxidation processes when treating several types of aqueous wastes. On one side its performance for the abatement of chloro-organic aromatic toxic pollutants, such as 4-chlorophenol and 2,4-dichlorophenol has been studied. On the other hand, wastewater from pulp and paper mills, which has been reported to be an indirect source of entry of chlorophenols in the aquatic environment, has been investigated. More in detail, it h...

  14. Removing 3,5-Dichlorophenol from Wastewater by Alternative Adsorbents

    Directory of Open Access Journals (Sweden)

    Kobetičová Hana

    2014-12-01

    Full Text Available The main objective of this paper is to evaluate an efficiency of 3,5 - dichlorophenol removal from wastewater by using alternative adsorbents. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and also atoms of chlorine. Chlorophenols may have a huge isomere variety that means there are differences in their chemical and physical properties. Due to their toxicity it is necessary to remove them from waste water and in this paper an alternative way of such process is described.

  15. Drug: D00149 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available 0149.gif Antibacterial [topical] Same as: C02124 CAS: 106-48-9 PubChem: 7847217 PDB-CCD: 4CH LigandBox: D001...D00149 Drug Parachlorophenol (JAN/USP); p-Chlorophenol C6H5ClO 128.0029 128.5563 D0

  16. Molecular characterization of anaerobic dehalogenation by Desulfitobacterium dehalogenans

    NARCIS (Netherlands)

    Smidt, H.

    2001-01-01

    Haloorganics such as chlorophenols and chlorinated ethenes are among the most abundant pollutants in soil, sediments and groundwater, mainly caused by past and present industrial and agricultural activities. Due to bioaccumulation and toxicity, these compounds threaten the integrity of the environme

  17. Degradation and O-methylation of chlorinated phenolic compounds by Rhodococcus and Mycobacterium strains.

    OpenAIRE

    Häggblom, M M; Nohynek, L J; Salkinoja-Salonen, M. S.

    1988-01-01

    Three polychlorophenol-degrading Rhodococcus and Mycobacterium strains were isolated independently from soil contaminated with chlorophenol wood preservative and from sludge of a wastewater treatment facility of a kraft pulp bleaching plant. Rhodococcus sp. strain CG-1 and Mycobacterium sp. strain CG-2, isolated from tetrachloroguaiacol enrichment, and Rhodococcus sp. strain CP-2, isolated from pentachlorophenol enrichment, mineralized pentachlorophenol and degraded several other polychlorina...

  18. Influence of cosubstrates in the anaerobic biodegradation of 2,4,6-thricholorophenol and methanogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Puyol, D.; Mohedano, A. F.; Rodriguez, J. J.; Sanz, J. L.

    2009-07-01

    Chlorophenols, very toxic organic compounds, are widely distributed in soils and water. These substances are related to cellular damage as they have mutagenic and carcinogenic characteristics. Aromatic compounds have been eliminated from wastewater under methanogenic conditions; however, in most of the cases the elimination rates are low and some toxic intermediated might be accumulated. (Author)

  19. 77 FR 58136 - Notice of Receipt of Requests To Voluntarily Cancel Certain Pesticide Registrations

    Science.gov (United States)

    2012-09-19

    ..., avoiding the use of profanity or personal threats. viii. Make sure to submit your comments by the comment... Greenhouse and Nursery Insecticide. 000675-00019 Bulk Amphyl Brand 2-Benzyl-4- Disinfectant. chlorophenol; o... KY050001 Propimax EC...... Propiconazole ME090004 Ethrel Brand Ethephon Ethephon Plant Regulator....

  20. 40 CFR Appendix D to Part 122 - NPDES Permit Application Testing Requirements (§ 122.21)

    Science.gov (United States)

    2010-07-01

    ... 19Vethylbenzene 20Vmethyl bromide 21Vmethyl chloride 22Vmethylene chloride 23V1,1,2,2-tetrachloroethane... 29Vtrichloroethylene 31Vvinyl chloride Acid Compounds 1A2-chlorophenol 2A2,4-dichlorophenol 3A2,4-dimethylphenol 4A4,6...) and Total Phenols Antimony, Total Arsenic, Total Beryllium, Total Cadmium, Total Chromium,...

  1. Manganese zinc ferrite nanoparticles as efficient catalysts for wet peroxide oxidation of organic aqueous wastes

    Indian Academy of Sciences (India)

    Manju Kurian; Divya S Nair

    2015-03-01

    Manganese substituted zinc nanoparticles, MnxZn1−xFe2O4 (x = 0.0, 0.25, 0.5, 0.75, 1.0) prepared by sol gel method were found to be efficient catalysts for wet peroxide oxidation of 4-chlorophenol. Complete degradation of the target pollutant occurred within 90 min at 70°C. Zinc substitution enhanced the catalytic efficiency and the unsubstituted ZnFe2O4 oxidized the target compound completely within 45 min. Studies on the effect of reaction variables revealed that only a small amount of the oxidant, H2O2 (3–4 mL) is required for complete degradation of 4-chlorophenol. More than 80% of 4-chlorophenol was removed at catalyst concentrations of 100 mg/L. Direct correlation between the amount of catalyst present and the extent of degradation of 4-chlorophenol was observed, ruling out hesterogeneous-homogeneous mechanism. The catalysts are reusable and complete degradation of target pollutant occurred after five successive runs. The extent of iron leaching was fairly low after five consecutive cycles indicating the mechanism to be heterogeneous.

  2. Green Technology for the Removal of Chloro-Organics from Pulp and Paper Mill Wastewater.

    Science.gov (United States)

    Choudhary, Ashutosh Kumar; Kumar, Satish; Sharma, Chhaya; Kumar, Vivek

    2015-07-01

    This study evaluates the treatment efficiency of a horizontal subsurface-flow constructed wetland (HSSF-CW) for the removal of chloro-organic compounds from pulp and paper mill wastewater. The surface area of the HSSF-CW unit was 5.25 m² and was planted with Colocasia esculenta. The wastewater was characterized for different chloro-organic compounds, that is, adsorbable organic halides (AOX), chlorophenolics, and chlorinated resin and fatty acids (cRFAs). Under a hydraulic retention time of 5.9 days, the average AOX, chlorophenolics, and cRFA removal from wastewater was 87, 87, and 93%, respectively. Some of the chlorophenolics were found to accumulate in the plant biomass and soil material. The mass balance studies show that a significant fraction of chlorophenolics and cRFA was degraded in the constructed wetland system. Modeling studies were carried out to estimate the first-order area-based removal rate constants (k) for chemical oxygen demand removal. The HSSF-CW was found to be an effective treatment technology for the remediation of pulp and paper mill wastewater. PMID:26163503

  3. Joint toxicity of mixtures of groups of organic aquatic pollutants to the guppy (Poecilia reticulata)

    NARCIS (Netherlands)

    Hermens, J.L.M.; Leeuwangh, Peter; Musch, Aalt

    1985-01-01

    In this study acute lethal concentrations (LC50) to the guppy (Poecilia reticulata) were determined for mixtures of 4 groups of aquatic pollutants. The groups were composed of 11 nonreactive, nonionized organic chemicals, 11 chloroanilines, 11 chlorophenols, and 9 reactive organic halides. Earlier s

  4. Inhibitory concentrations of 2,4D and its possible intermediates in sulfate reducing biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Cruz, Ulises [Department of Biotechnology, Environmental Science and Technology, Universidad Autonoma Metropolitana-Iztapalapa, Ave. San Rafael Atlixco 186, Vicentina, 09340 D.F. (Mexico); Celis, Lourdes B. [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216 San Luis Potosi, S.L.P. (Mexico); Poggi, Hector [Department of Biotechnology and Bioengineering, CINVESTAV, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, 07360 D.F. (Mexico); Meraz, Monica, E-mail: meraz@xanum.uam.mx [Department of Biotechnology, Environmental Science and Technology, Universidad Autonoma Metropolitana-Iztapalapa, Ave. San Rafael Atlixco 186, Vicentina, 09340 D.F. (Mexico)

    2010-07-15

    Different concentrations of the herbicide 2,4-dichlorophenoxyacetic acid (2,4D) and its possible intermediates such as 2,4-dichlorophenol (2,4DCP), 4-chlorophenol (4CP), 2-chlorophenol (2CP) and phenol, were assayed to evaluate the inhibitory effect on sulfate and ethanol utilization in a sulfate reducing biofilm. Increasing concentrations of the chlorophenolic compounds showed an adverse effect on sulfate reduction rate and ethanol conversion to acetate, being the intermediate 2,4DCP most toxic than the herbicide. The monochlorophenol 4CP (600 ppm) caused the complete cessation of sulfate reduction and ethanol conversion. The ratio of the electron acceptor to the electron donor utilized as well as the sulfate utilization volumetric rates, diminished when chlorophenols and phenol concentrations were increased, pointing out to the inhibition of the respiratory process and electrons transfer. The difference found in the IC{sub 50} values obtained was due to the chemical structure complexity of the phenolic compounds, the number of chlorine atoms as much as the chlorine atom position in the phenol ring. The IC{sub 50} values (ppm) indicated that the acute inhibition on the biofilm was caused by 2,4DCP (17.4) followed by 2,4D (29.0), 2CP (99.8), 4CP (108.0) and phenol (143.8).

  5. Removal of aqueous phenol and phenol derivatives by immobilized potato polyphenol oxidase

    Directory of Open Access Journals (Sweden)

    GORAN ROGLIĆ

    2011-04-01

    Full Text Available Phenols containing halogens, which tend to deactivate the aromatic nuclei, constitute a significant category of highly toxic and difficult-to-degrade pollutants, which arise from a wide variety of industries. The main purpose of this study was to obtain an inexpensive immobilized enzyme for the removal of phenols. Partially purified potato polyphenol oxidase (PPO was immobilized onto different commercial and laboratory produced carriers. Three of the obtained biocatalysts, with the highest PPO activities, namely Eupergit C250L–PPO; Celite–PPO and CelluloseM–PPO, were tested in a batch reactor for the removal of phenol, 4-chlorophenol and 4-bromophenol. In the case of 2.5 mM substrates with Eupergit C250L–PPO, an around 45 % removal of 4-bromophenol was achieved, while the removals 4-chlorophenol and phenol were 35 and 20 %, respectively. The reusability of Eupergit C250L–PPO for the removal of 4-chlorophenol was tested. After eight repeated tests, the efficiency of 4-chlorophenol removal by Eupergit C250L–PPO immobilisate had decreased to 55 %.

  6. Purification and characterization of the 3-chloro-4-hydroxy-phenylacetate reductive dehalogenase of Desulfitobacterium hafniense

    DEFF Research Database (Denmark)

    Christensen, Nina; Ahring, Birgitte Kiær; Wohlfarth, Gert;

    1998-01-01

    The membrane-bound 3-chloro-4-hydroxyphenylacetate (Cl-OHPA) reductive dehalogenase from the chlorophenol- educing anaerobe Desulfitobacterium hafniense was purified 11.3-fold to apparent homogeneity in the presence of the detergent CHAPS. The purified dehalogenase catalyzed the reductive dechlor...

  7. Inhibition of dehydrogenase activity in petroleum refinery wastewater bacteria by phenolic compounds

    Directory of Open Access Journals (Sweden)

    Gideon C. Okpokwasili

    2010-04-01

    Full Text Available The toxicity of phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol on Pseudomonas, Bacillus and Escherichia species isolated from petroleum refinery wastewater was assessed via inhibition of dehydrogenase enzyme activity. At low concentrations, 2-nitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol stimulated dehydrogenase activity and at sufficient concentrations, phenolic compounds inhibited dehydrogenase activities. Generally, phenol is less toxic than substituted phenols. Estimations of the degree of inhibition/stimulation of dehydrogenase activities showed significant dose-dependent responses that are describable by logistic functions. The toxicity thresholds varied significantly (P < 0.05 among the bacterial strains and phenolic compounds. The median inhibitory concentrations (IC50s ranged from 4.118 ± 0.097 mg.L-1 for 4-nitrophenol against Pseudomonas sp. DAF1 to 1407.997 ± 7.091 mg.L-1 for phenol against Bacillus sp. DISK1. This study suggested that the organisms have moderate sensitivity to phenols and have the potential to be used as indicators for assessment of chemical toxicity. They could also be used as catalysts for degradation of phenols in effluents.

  8. Transcriptional profiling of Gram-positive Arthrobacter in the phyllosphere: induction of pollutant degradation genes by natural plant phenolic compounds

    NARCIS (Netherlands)

    Scheublin, T.R.; Deusch, S.; Moreno-Forero, S.K.; Müller, J.A.; van der Meer, J.R.; Leveau, J.H.J.

    2014-01-01

    Arthrobacter chlorophenolicus A6 is a Gram-positive, 4-chlorophenol degrading soil bacterium that was recently shown to be an effective colonizer of plant leaf surfaces. The genetic basis for this phyllosphere competency is unknown. In this paper, we describe the genome-wide expression profile of A.

  9. An efficient and green synthesis of novel benzoxazole under ultrasound irradiation.

    Science.gov (United States)

    Nikpassand, Mohammad; Fekri, Leila Zare; Farokhian, Pegah

    2016-01-01

    Ultrasound as green process and an alternative energy source was investigated for the environmentally benign synthesis of novel benzoxazoles from different azo-linked salicylic acid derivatives and 2-amino-4-chlorophenol in short reaction time and high yield. These benzoxazole compounds have been characterized by elemental analysis, FT-IR, (1)H NMR and (13)C NMR spectroscopy.

  10. 微电解接触氧化系统处理水源中2-氯酚研究

    Institute of Scientific and Technical Information of China (English)

    张丹; 吴昊; 马杰; 张景辉

    2012-01-01

    The characteristic and mechanism of 2-chlorophenol degradation in a micro-electrolysis contact oxidation system were investigated. The degradation efficiency of 2-chlorophenol was higher in acidic solution than that of in neutral or alkaline solution. Addition of activated carbon could make 2-chlorophenol easier be degraded by the surface contact catalysis. The dissolved oxygen in solution could take part in the electrode reaction and intensify the degradation of 2-chlorophenoL Most intermediate products contained 1,2-benzenediol,glycerol,oxalic acid and acetic acid. By the analysis of intermediates of degradation of 2-chlorophenol,its possible degradation pathway is brought up.%在微电解接触氧化系统中,研究了2-氯酚的降解特性和机理。在酸性溶液中,2-氯酚的降解效率比其在中性和碱性溶液的高。向其中加入活性炭,由于表面催化的作用使得2-氯酚更易降解。溶液中的溶解氧参与电极反应并促进2-氯酚的降解。降解产物有1,2-苯二酚、丙三醇、草酸和乙酸。通过对中间产物的分析,提出了2-氯酚可能的降解途径。

  11. Formation of chlorinated organic compounds in fluidized bed combustion of recycled fuels

    International Nuclear Information System (INIS)

    Four tests of co-combustion of recycled fuels (REP) with peat and coal in the 15 kW fluidized bed reactor were performed. The recycled fuel was so-called dry fraction in four vessels sampling at Keltinmaeki. In three tests a part of peat energy was replaced with coal. The mixtures were prepared so that in all mixtures 25 % of energy was recycled fuel and 75 % was either peat or the mixture of peat and coal. The concentrations of polyaromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and chlorophenols decreased with increasing part of coal due to the increasing sulphur/chlorine ratio. Principal Component Analysis (PCA) and Partial Least Square regression analysis (PLS) showed that the chlorine, copper and sulphur contents of the fuel effected most on the concentrations of chlorophenols, chlorobenzenes, PCBs and PCDDs/PCDFs. Other variables influencing on a model were the lead concentration and the sulphur/chlorine ratio in fuel and the hydrogen chloride concentration of the flue gas. The concentrations of chlorophenols and chlorobenzenes were also significant for PCDD/PCDF concentrations in flue gas. The sulphur, chlorine, copper and chromium contents in fly ash and the temperature of the reactor influenced on the chlorophenol, chlorobenzene, PCB and PCDD/PCDF concentrations in fly ash. The chlorophenol and chlorobenzene contents in fly ash, the sulphur/chlorine ratio and the lead content in fuel, the sulphur dioxide, hydrogen chloride and carbon monoxide concentrations in flue gas had also influence on PCDD/PCDF concentrations in fly ash

  12. Formation of chlorinated organic compounds in fluidized bed combustion of recycled fuels; Kloorattujen orgaanisten yhdisteiden muodostuminen kierraetyspolttoaineiden leijukerrospoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Vesterinen, R.; Kallio, M.; Kirjalainen, T.; Kolsi, A.; Merta, M. [VTT Energy, Jyvaeskylae (Finland)

    1997-10-01

    Four tests of co-combustion of recycled fuels (REP) with peat and coal in the 15 kW fluidized bed reactor were performed. The recycled fuel was so-called dry fraction in four vessels sampling at Keltinmaeki. In three tests a part of peat energy was replaced with coal. The mixtures were prepared so that in all mixtures 25 % of energy was recycled fuel and 75 % was either peat or the mixture of peat and coal. The concentrations of polyaromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and chlorophenols decreased with increasing part of coal due to the increasing sulphur/chlorine ratio. Principal Component Analysis (PCA) and Partial Least Square regression analysis (PLS) showed that the chlorine, copper and sulphur contents of the fuel effected most on the concentrations of chlorophenols, chlorobenzenes, PCBs and PCDDs/PCDFs. Other variables influencing on a model were the lead concentration and the sulphur/chlorine ratio in fuel and the hydrogen chloride concentration of the flue gas. The concentrations of chlorophenols and chlorobenzenes were also significant for PCDD/PCDF concentrations in flue gas. The sulphur, chlorine, copper and chromium contents in fly ash and the temperature of the reactor influenced on the chlorophenol, chlorobenzene, PCB and PCDD/PCDF concentrations in fly ash. The chlorophenol and chlorobenzene contents in fly ash, the sulphur/chlorine ratio and the lead content in fuel, the sulphur dioxide, hydrogen chloride and carbon monoxide concentrations in flue gas had also influence on PCDD/PCDF concentrations in fly ash

  13. IMPACT OF SPLITTING OF CHEMICAL DOSES IN C STAGE ON TOXICITY DURING PAPER PRODUCTION

    Directory of Open Access Journals (Sweden)

    Divya Prakash

    2014-09-01

    Full Text Available The laboratory generated spent bleach liquor from the chlorination stages of Bamboo pulp has been analysed both qualitatively and quantitatively (without washing and with washing for various chlorophenolics acids using gas chromatography. A number of chlorinated derivatives of phenols, catechols, guaiacols, syringaldehydes have been identified. The concentrations of various compounds identified have also been compared with the reported 96LC50 values. The results indicates that splitting of chlorine dose gives 47% lower formation of chlorinated phenolic compounds in without washing in splitting of chemical dose in C stage and the total chlorophenolic compounds decrease by 54% which is 7% more in comparison to chlorination stage (Dosage being splitted into two equal parts and no in between washing has taken place.

  14. Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water

    Energy Technology Data Exchange (ETDEWEB)

    Yang Ji, E-mail: yangji@ecust.edu.cn [School of Resources and Environmental Engineering, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); Cao Limei; Guo Rui; Jia Jinping [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2010-12-15

    Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m{sup 2} g{sup -1}, the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly.

  15. Modelling and simulation of photocatalytic oxidation mechanism of chlorohalogenated substituted phenols in batch systems: Langmuir-Hinshelwood approach.

    Science.gov (United States)

    Khuzwayo, Z; Chirwa, E M N

    2015-12-30

    This study investigated, modelled and simulated the influence of multi-chlorohalogenation in heterogeneous photocatalytic degradation of substituted phenols (pentachlorophenol (PCP), trichlorophenol (TCP), dichlorophenol (DCP), and monochlorophenol (CP)). The Langmuir-Hinshelwood approach was applied to determine oxidation kinetics. Aquasim 2.0 computational software was used to model, simulate and estimate model parameters of the different chlorophenols. Chemical adsorption equilibrium isotherms for the four chlorophenols and phenol were studied and modelled for adsorption onto titanium dioxide (TiO2) semiconductor catalyst. Langmuir adsorption parameters were determined and used to calculate adsorption constant and maximum adsorption capacity. The adsorption of chloride phenolics onto titanium dioxide catalyst increased in the order of 4 - CP TCP > DCP ≥ 4 - CP. Photocatalytic parameters were calculated and estimated along with sensitivity and uncertainty analyses. PMID:26223020

  16. Microbial dehalogenation of trichlorophenol by a bacterial consortium: characterization and mechanism

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chlorinated phenolic compounds are a class of toxic and refractory organic pollutants. The pollution caused by chlorophenols poses serious ecological and environmental problems. A stable bacterial consortium capable of reductively dechlorinating trichlorophenol was isolated using chlorophenol as the sole source of carbon and energy. The physiological characteristics of the mixed cultures were studied and the results show that the consortium could use pyruvate as the carbon and energy source. The fermentation of pyruvate, sulfate reduction and dechlorination process proceeded strictly in succession within this consortium. The effect of specific inhibitors on the dechlorinating activity of the consortium was investigated, and the results indicate that sulfate and molybdate (1 mmol/L) have a strong inhibitive influence on the dechlorination activity. Fluorescence in situ hybridization (FISH) technique was applied to analyzing the composition of the consortium and the results reveal that one major subpopulation within the consortium was phylogenetically affiliated to gamma and delta subclass of Proteobacteria.

  17. Solar photo-degradation of pesticides in water by sodium deca-tungstate

    Energy Technology Data Exchange (ETDEWEB)

    Texier, I.; Giannotti, C. [Institut de Chimie des Substances Naturelles, 91 - Gif sur Yvette (France); Delaire, J. [PPSM, URA 1906, 94 - Cachan (France); Malato, S.; Richter, C. [Plataforma Solar de Almeria, Madrid (Spain)

    1999-03-01

    Solar photo-decomposition of aqueous solutions of phenol, 4-chlorophenol, 2,4-di-chlorophenol, bromoxynil, atrazine, imidachloprid and oxamyl in the presence of two photo-catalysts titanium dioxide TiO{sub 2} and sodium deca-tungstate Na{sub 4}W{sub 10}O{sub 32} is reported. Titanium dioxide appears to be the most efficient photo-catalyst concerning the rate of photo-degradation and mineralisation of the pure compounds. However, when the pesticides are used in formulated solutions, the deca-tungstate anion becomes as efficient or even more efficient than TiO{sub 2}. The mechanisms of the photo-degradation in the presence of the two photo-catalysts are discussed. They appear to be different, accounting for the observed difference of reactivity. (authors)

  18. Performance Evaluation of AOP/Biological Hybrid System for Treatment of Recalcitrant Organic Compounds

    Directory of Open Access Journals (Sweden)

    Stanford S. Makgato

    2010-01-01

    Full Text Available Process water from nuclear fuel recovery unit operations contains a variety of toxic organic compounds. The use of decontamination reagents such as CCl4 together with phenolic tar results in wastewater with a high content of chlorophenols. In this study, the extent of dehalogenation of toxic aromatic compounds was evaluated using a photolytic advanced oxidation process (AOP followed by biodegradation in the second stage. A hard-to-degrade toxic pollutant, 4-chlorophenol (4-CP, was used to represent a variety of recalcitrant aromatic pollutants in effluent from the nuclear industry. A UV-assisted AOP/bioreactor system demonstrated a great potential in treatment of nuclear process wastewater and this was indicated by high removal efficiency (>98% under various 4-CP concentrations. Adding hydrogen peroxide (H2O2 as a liquid catalyst further improved biodegradation rate but the effect was limited by the scavenging of OH• radicals under high concentrations of H2O2.

  19. Corrosivity of paper mill effluent and corrosion performance of stainless steel.

    Science.gov (United States)

    Ram, Chhotu; Sharma, Chhaya; Singh, A K

    2015-01-01

    Present study relates to the corrosivity of paper mill effluent and corrosion performance of stainless steel (SS) as a construction material for the effluent treatment plant (ETP). Accordingly, immersion test and electrochemical polarization tests were performed on SS 304 L, 316 L and duplex 2205 in paper mill effluent and synthetic effluent. This paper presents electrochemical polarization measurements, performed for the first time to the best of the authors' information, to see the influence of chlorophenols on the corrosivity of effluents. The corrosivity of the effluent was observed to increase with the decrease in pH and increase in Cl- content while the addition of SO4- tends to inhibit corrosion. Mill effluent was found to be more corrosive as compared to synthetic effluent and has been attributed to the presence of various chlorophenols. Corrosion performance of SS was observed to govern by the presence of Cr, Mo and N contents. PMID:25188842

  20. Molecular characterization of anaerobic dehalogenation by Desulfitobacterium dehalogenans

    OpenAIRE

    Smidt, H.

    2001-01-01

    Haloorganics such as chlorophenols and chlorinated ethenes are among the most abundant pollutants in soil, sediments and groundwater, mainly caused by past and present industrial and agricultural activities. Due to bioaccumulation and toxicity, these compounds threaten the integrity of the environment, and human and animal health. A recently discovered, phylogenetically diverse, group of anaerobic so-called halorespiring bacteria is able to couple the reductive dehalogenation of various haloo...

  1. Practical Engineering Aspects of Catalysis in Microreactors

    OpenAIRE

    Křišťál, J. (Jiří); Stavárek, P. (Petr); Vajglová, Z. (Zuzana); Vondráčková, M. (Magdalena); Pavlorková, J. (Jana); Jiřičný, V. (Vladimír)

    2015-01-01

    This work presents a brief review of microreactor applications for different types of catalytic reactions. Practical aspects of four selected case studies are discussed in detail: enzymatic glycerolysis, hydrogenation of isobutene, stereoselective catalytic transfer hydrogenation and photochemical oxidation of 4-chlorophenol. The common benefits resulting from the use of microreactors are documented, and include the excellent control of operating condition, efficient heat transfer, tailored d...

  2. Treatment of malodorants in air by the UV/ozone technique

    International Nuclear Information System (INIS)

    Laboratory work has shown that a gas scrubber using uv/ozone as the oxidant was effective in destroying model compounds, and that the UV radiation was better applied in the sump liquor rather than in the spray section. A field trial on a plant making selective weed killers has demonstrated that the technique was able to reduce the concentration of malodorants (mainly chlorophenols) by two to three orders of magnitude in a single pass

  3. Some aspects of the etiology of non-Hodgkin's lymphoma.

    OpenAIRE

    Hardell, L; G. Lindström; B. van Bavel; Fredrikson, M; Liljegren, G

    1998-01-01

    In epidemiologic studies, non-Hodgkin's lymphoma (NHL) has been associated with exposure to chemicals such as phenoxyacetic acids; chlorophenols; dioxins; organic solvents including benzene, polychlorinated biphenyls, chlordanes; and immunosuppressive drugs. Experimental evidence and clinical observations indicate that these chemicals may impair the immune system. The risk is increased for NHL in persons with acquired and congenital immune deficiency as well as autoimmune disorders. Also, cer...

  4. Pyrolysis products of PCBs.

    OpenAIRE

    Paasivirta, J.; R. Herzschuh; Humppi, T; Kantolahti, E; Knuutinen, J; Lahtiperä, M; Laitinen, R; Salovaara, J; Tarhanen, J; Virkki, L

    1985-01-01

    Model compound studies which were previously done for impurities and environmental residues of chlorophenols and for wastes of chlorination processes were extended to the impurities and pyrolysis products of polychlorinated biphenyls (PCBs). Model compounds were commercial products or synthesized and their structures proven by spectroscopic methods. These models were used as analytical reference substances in GC/ECD and GC/MS studies of the pyrolyzed PCB samples. In addition to previously kno...

  5. Extrapolation of biodegradation results to groundwater aquifers: reductive dehalogenation of aromatic compounds.

    OpenAIRE

    Gibson, S. A.; Suflita, J M

    1986-01-01

    The reductive biodegradation of a variety of haloaromatic substrates was monitored in samples from two sites within a shallow anoxic aquifer and was compared with freshwater sediment and sewage sludge. The metabolic capacity existing in methane-producing aquifer material was very similar to that in sediment in that three of four chlorobenzoates, five of seven chlorophenols, and one of two chlorophenoxyacetate herbicides were reductively dehalogenated in both types of incubations. The 2,4-dich...

  6. The molecular analysis of transgenic \\kur{Lycopersicon esculentum} plants harbouring incorporated pmi gene for phosphomannose isomerase

    OpenAIRE

    PŘIKRYLOVÁ, Pavla

    2007-01-01

    The aim of this study was to analyze number of incorporated T-DNA harbouring pmi and nptII transgenes and expression of the pmi gene in tomato transformants using Southern blot and Northern blot methods. The presence of a functional PMI protein was assesed using PMI-assay with Chlorophenol red dye. Mannose selection of tomato seeds was established and segregation patterns in T1 progeny were studied.

  7. Characterization and Description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an Aryl-Halorespiring Facultative Anaerobic Myxobacterium

    OpenAIRE

    Sanford, Robert A.; Cole, James R.; Tiedje, James M

    2002-01-01

    Five strains were isolated which form a physiologically and phylogenetically coherent group of chlororespiring microorganisms and represent the first taxon in the Myxobacteria capable of anaerobic growth. The strains were enriched and isolated from various soils and sediments based on their ability to grow using acetate as an electron donor and 2-chlorophenol (2-CPh) as an electron acceptor. They are slender gram-negative rods with a bright red pigmentation that exhibit gliding motility and f...

  8. Photocatalytic activity of porous multiwalled carbon nanotube-TiO2 composite layers for pollutant degradation.

    Science.gov (United States)

    Zouzelka, Radek; Kusumawati, Yuly; Remzova, Monika; Rathousky, Jiri; Pauporté, Thierry

    2016-11-01

    TiO2 nanoparticles are suitable building blocks nanostructures for the synthesis of porous functional thin films. Here we report the preparation of films using brookite, P25 titania and anatase pristine nanoparticles and of nanocomposite layers combining anatase nanoparticles and multi-walled carbon nanotube (MWCNT) at various concentrations. The structure and phase composition of the layers were characterized by X-ray diffraction and Raman spectroscopy. Their morphology and texture properties were determined by scanning electron microscopy and krypton adsorption experiments, respectively. Additionally to a strong absorption in the UV range, the composites exhibited light absorption in the visible range as well. The photocatalytic performance of the layers was tested in the degradation of aqueous solutions of 4-chlorophenol serving as a model of an eco-persistent pollutant. Besides the determination of the decrease in the concentration of 4-chlorophenol, also the formation of intermediate degradation products, namely hydroquinone and benzoquinone, was followed. The presence of MWCNTs had a beneficial effect on the photocatalytic performance, a marked increase in the photocatalytic degradation rate constant being observed even at very low concentrations of MWCNTs. Compared to a P25 reference layer, the first order rate reaction constant increased by about 100% for the composite films containing MWCNTs at concentrations above 0.6 wt%. The key parameters for the enhancement of the photocatalytic performance are discussed. The presence of carbon nanotubes influences beneficially the degradation of 4-chlorophenol by an attack of the primarily photoproduced hydroxyl radicals onto the 4-chlorophenol molecules. The degradation due to the direct charge transfer is practically not influenced at all. PMID:27262272

  9. Pulsed electrical discharges in water for removal of organic pollutants: a comparative study

    OpenAIRE

    Dang, T. H.; Denat, A.; Lesaint, O.; Teissedre, G.

    2009-01-01

    Abstract In this study, the efficiency of different types of pulsed electrical discharges for the removal of organic pollutants from wastewater has been determined. Three discharge types, either in the water volume or in close proximity to the water surface are studied. The production of hydrogen peroxide in pure water, and the degradation of two typical pollutants (4-chlorophenol and 4-nitrophenol) is measured together with the amount of electrical energy d...

  10. IMPACT OF C STAGE VARIABLES ON THE TOXICITY DURING PAPER PRODUCTION IN MILLS

    OpenAIRE

    Divya Prakash; Kumar, S

    2013-01-01

    Chlorinated phenolics are formed during chlorination stage of pulp bleaching. These phenolics are dissolved in the alkaline extraction stage. The bleach plant effluent therefore contains these compounds in appreciable amount. As these chlorophenolics are highly toxic in nature, efforts have been made to reduce their concentration by changing the bleaching parameters. In the present studies experiments were conducted with bamboo pulp employing CEH sequence of bleaching under varying conditions...

  11. Effect of bromine substituents in the formation of PXDD from poly halogenated phenols

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, T.; Ohono, T.; Weber, R.

    2002-07-01

    The condensation of chlorophenols has been studied extensively in the last two decades and was discussed as one mechanism in particular for the formation of PCDD in thermal processes. Brominated flame retardants and brominated and brominated-chlorinated dibenzodioxins and dibenzofurans have received increased attention recently due to the growing use of brominated flame retardants during the last decade. This is resulting than increase of brominated compounds in waste (e.g. Electric and electronic shredder waste), containing a considerable amount of bromine, in the form of brominated flame retardants. Many studies reported on the formation of PBDD/PBDF from brominated diphenylethers, or bromophenosl. However with the exception of Sodhu et al, a comparison of the condensation behaviour of bromophenols and chlorophenols was not done. The condensation of brominated phenols is interesting from several aspects. Bromophenols are used as flame retardants and might be a source of PBDD/F during thermal stress. Bromophenols can also be generated during the combustion/pyrolysis of bromodiphenylether or tetrabromobisphenol A containing material, serving as potential precursors for the formation of PBDD/PBDF. Further, in municipal waste incinerators with sufficient secondary combustion, the largest amount of chlorinated aromatic compounds (PCDD, PCDF, PCBs, PCNs, and chlorophenols) are formed in the cooling section (boiler, duct, dust filtration). Therefore in combustion processes involving high concentrations of brominated flame retardants, mixed PXDD/PXDF might be formed by condensation reactions of precursors or de novo synthesis in the cooling zone. Therefore we investigated the condensation of abrominated phenol in more detail and compare it to the condensation reaction of the analogous chlorophenol. (Author)

  12. Effect of adaptation to phenol on biodegradation of monosubstituted phenols by aquatic microbial communities.

    OpenAIRE

    Shimp, R J; Pfaender, F K

    1987-01-01

    The adaptation of a mixed aquatic microbial community to phenol was examined in microcosms receiving phenol as a sole carbon source. Extended exposure (adaptation) to phenol resulted in adaptation of the microbial community to the structurally related aromatic compounds m-cresol, m-aminophenol, and p-chlorophenol. The increased biodegradation potential of the phenol-adapted microbial community was accompanied by a concurrent increase in the number of microorganisms able to degrade the three t...

  13. Isolation of Arthrobacter species from the phyllosphere and demonstration of their epiphytic fitness

    OpenAIRE

    Scheublin, T.R.; Leveau, J.H.J.

    2013-01-01

    Bacteria of the genus Arthrobacter are common inhabitants of the soil environment, but can also be recovered from leaf surfaces (the phyllosphere). Using enrichment cultures on 4-chlorophenol, we succeeded in specifically isolating Arthrobacter bacteria from ground cover vegetation in an apple orchard. Based on 16S rRNA gene sequencing, the isolates were found to belong to at least three different species of Arthrobacter. Compared to the model bacterial epiphyte Pantoea agglomerans, the Arthr...

  14. Quick and easy method for determination of priority phenolic compounds in water and wastewater

    OpenAIRE

    Bhupander Kumar; Virendra Kumar Verma; Chandra Shekhar Sharma; Akolkar, Avinash B.

    2014-01-01

    Phenols and phenolic compounds are ubiquitous contaminants in the environment. Due to toxic potential, some phenolic compounds mainly chlorophenols and nitrophenols have been classified as priority pollutants. They enter into the environment through various sources such as industrial, domestic and vehicular emissions. For compliance of national and international regulations, various analytical methods have been developed for assessment in the environmental matrices. This paper presents quick,...

  15. Chloroanisoles may explain mold odor and represent a major indoor environment problem in Sweden.

    Science.gov (United States)

    Lorentzen, J C; Juran, S A; Nilsson, M; Nordin, S; Johanson, G

    2016-04-01

    Indoor mold odor is associated with adverse health effects, but the microbial volatiles underlying mold odor are poorly described. Here, chloroanisoles were studied as potential key players, being formed by microbial metabolism of chlorophenols in wood preservatives. Using a three-stage approach, we (i) investigated the occurrence of chloroanisoles in buildings with indoor air quality problems, (ii) estimated their frequency in Sweden, and (iii) evaluated the toxicological risk of observed chloroanisole concentrations. Analyses of 499 building materials revealed several chloroanisole congeners in various types of buildings from the 1950s to 1970s. Evaluation of Swedish records from this time period revealed three coinciding factors, namely an unprecedented nationwide building boom, national regulations promoting wood preservatives instead of moisture prevention, and use of chlorophenols in these preservatives. Chlorophenols were banned in 1978, yet analysis of 457 indoor air samples revealed several chloroanisole congeners, but at median air levels generally below 15 ng/m(3) . Our toxicological evaluation suggests that these concentrations are not detrimental to human health per se, but sufficiently high to cause malodor. Thereby, one may speculate that chloroanisoles in buildings contribute to adverse health effects by evoking odor which, enhanced by belief of the exposure being hazardous, induces stress-related and inflammatory symptoms. PMID:25858592

  16. Removal of 2,4-dichlorophenol and pentachlorophenol from waters by sorption using coal fly ash from a Portuguese thermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Estevinho, Berta N. [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Martins, Isabel [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Ratola, Nuno [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Alves, Arminda [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Santos, Lucia [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)]. E-mail: lsantos@fe.up.pt

    2007-05-08

    Chlorophenols are one of the most important groups of priority pollutants, due to their high toxicity, mutagenicity and carcinogenicity. Although activated carbon has been the preferred choice for the removal of such pollutants from wastewaters, the search for cheaper alternative sorbents became common in the last years. Fly ash, a by-product from coal burning power plants, has a surface composition that may enable the sorption of specific organic compounds. Therefore, this feasibility study presents the optimization of the operating parameters of a fixed-bed column containing fly ash particles, percolated by aqueous solutions of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) with concentrations of 1 and 100 {mu}g/ml. Both chlorophenols were analysed by gas chromatography with electron capture detection (GC-ECD), after solid-phase microextraction (SPME), with limits of detection (LODs) of 7.28 {mu}g/l for 2,4-DCP and 1.76 {mu}g/l for PCP. Removal efficiencies above 99% were obtained for an initial concentration of 10 {mu}g/ml of chlorophenols. Column saturation was achieved after 7 h of continuous operation for 2,4-DCP and 10 h for the PCP for feed levels of 10 {mu}g/ml. Fly ash exhibited more affinity towards the sorption of PCP, in comparison to 2,4-DCP.

  17. Simultaneous anaerobic-aerobic biodegradation of halogenated phenolic compound under oxygen-limited conditions

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuan-cai; LAN Hui-xia; ZHAN Huai-yu; FU Shi-yu

    2005-01-01

    The successful application of co-immobilized aerobic-anaerobic biomaes under limited aeration in wastewater treatment systems would eliminate the problems associated with the intermediates mono-chlorophenol(MCP) and di-chlorophenol(DCP) accumulations. With low initial pentachlorophenol(PCP) concentration, all PCP could be completely removed under oxygen-limited strict anaerobic conditions,and the removal efficiencies with different initial haedspace oxygen percentage(IHOP) were not obviously different from each other. While at high initial PCP concentration, under strictly anaerobic conditions PCP and their intermediates were clearly higher than that under other conditions, and produced obvious accumulation, the highest PCP reduction was achieved by the system receiving 30 IHOP, oxygen-limited system also exhibited lower residual TOC concentration and lower concentration of metabolic intermediates MCP and DCP. These results suggested that under strictly anaerobic condition the reductive dechlorination of low chlorinated compounde became rate limiting in the reductive dechlorination pathway, less chlorinated compounds be more amenable to aerobic degradation, and the aerobes of outer layers could function under limited oxygen. The co-immobilized aerobic-anaerobic biomass for methanogeneeis under limited-aeration for chlorophenol degradation might be an attractive and efficient altemative for the sequential anaerobic/aerobic system to achieve mineralization of a broad range of recalcitrance highly chlorinated organics and low final TOC concentrations.

  18. Gamma radiolytic eradication of methoxychlor in aqueous media. The degradation pathways using HPLC and SPME-GC-MS

    Energy Technology Data Exchange (ETDEWEB)

    Butt, S.B.; Zafar, A. [PINSTECH, Nilore, Islamabad (Pakistan). Central Analytical Facility Div.; Riaz, M. [PINSTECH, Nilore, Islamabad (Pakistan). Chemistry Div.

    2013-08-01

    The gamma radiation-induced degradation of environmental pollutant methoxychlor in water was investigated. A {sup 60}Co gamma radiation source with a dose rate of 372 Gy h{sup -1} was used for gamma irradiation of 1 mg L{sup -1} and 10 mg L{sup -1} methoxychlor in water with a varied absorbed dose of 1-5 kGy. A single step clean up and pre-concentration procedure based on solid phase micro-extraction was optimized. The extent of radiolytic degradation was monitored by reversed phase HPLC-UV and GC-ECD. The trace and ultra trace level degradation products were identified using GC-MS-SPME by comparing their mass spectra with the NIST 98 m mass spectral library. Most of the generated products for 4 kGy dose are substituted chlorophenols. The reaction pathways of these substituted chlorophenols and benzophenone formation are also proposed. However, generated chlorophenols disappeared along with methoxychlor for an absorbed dose of 5 kGy. The attained degradation of methoxychlor is {proportional_to} 95% that reflects the potential use of ionization radiation for wastewater treatment. (orig.)

  19. The adsorptive properties of powdered carbon materials with a strongly differentiated porosity and their applications in electroanalysis and solid phase microextraction.

    Science.gov (United States)

    Kuśmierek, K; Sankowska, M; Skrzypczyńska, K; Świątkowski, A

    2015-05-15

    The adsorption of 4-chlorophenol from an aqueous solution on carbonaceous materials (one carbon black and two powdered activated carbons) with a strongly differentiated porosity was investigated. The kinetic data were fitted well to the pseudo-second order model. The amount of 4-chlorophenol adsorbed at equilibrium was increased with an increase in the specific surface area of the tested materials. The adsorption isotherms were analyzed using the Langmuir and Freundlich models. The Langmuir isotherm was slightly favorable (R(2)>0.99) rather than the Freundlich isotherm (R(2)>0.98). Carbon materials were also used for the modification of carbon paste electrodes as well as for the preparation of novel solid phase microextraction fibers. The peak current of the differential pulse voltammetry curves was increased along with the amount of added carbon paste electrode modifier. The signal response was closely related to the porosity of the materials used, and increased with the increase in the specific surface area. The amount of 4-chlorophenol extracted from the samples by the solid phase microextraction fiber's surface was also correlated with the specific surface area of the tested materials. All the novel fibers were better than the commercially available fibers prepared from polidimethylosiloxane. PMID:25660709

  20. Effect of humic constituents on the transformation of chlorinated phenols and anilines in the presence of oxidoreductive enzymes or birnessite

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.W.; Dec, J.; Bollag, J.M. (Pennsylvania State Univ., University Park, PA (United States)); Kim, J.E. (Kyngpook National Univ., Taegu (Korea, Republic of). Dept. of Agricultural Chemistry)

    1999-06-15

    Chlorinated phenols and anilines are transformed and detoxified in soil through oxidative coupling reactions mediated by enzymes or metal oxides. The reactions may be influences by humic constituents, such as syringaldehyde or catechol, that originate from lignin decomposition and are also subject to oxidative coupling. In this study, the effect of humic constituents on xenobiotic transformation was evaluated in vitro based on the determination of unreacted chlorophenols and chloroanilines. In experiments with peroxidase, laccase, and birnessite, the transformation of most chlorophenols was considerably enhanced by the addition of syringaldehyde. Less enhancement was observed using 4-hydroxybenzoic acid, and the addition of catechol resulted in a reduction of most transformations. The opposite was observed in experiments with tyrosinase, in which case catechol caused considerable enhancement of chlorophenol transformation. The varying effect of catechol can be explained by different transformation mechanisms involving either o-quinone coupling or free radical coupling. Regardless of the agent used to mediate the reactions, chloroanilines seemed to undergo nucleophilic addition to quinone oligomers, which resulted from coupling of the humic constituents. Catechol, which readily forms quinones and quinone oligomers, was most efficient in enhancing these reactions.

  1. Dechlorination of pentachlorophenol using nanoscale Fe/Ni particles: Role of nano-Ni and its size effect

    International Nuclear Information System (INIS)

    The dechlorination of pentachlorophenol (PCP) using nano-Fe together with different size of nano-Ni particles (30, 50, 80, and 100 nm) was investigated. The results indicated that nano-Ni particles could improve the dechlorination of PCP. The X-ray powder diffraction (XRD) analysis suggested that nano-Ni particles might serve as catalyst for dechlorination. The decrease of nano-Ni particle size resulted in the increase of PCP transformation and chloride release. The accumulation of several intermediates, such as phenol, 2-chlorophenol, 3-chlorophenol and 4-chlorophenol indicated the probable changes of the reaction pathway for PCP dechlorination. The corrosion products of Fe were detected using XRD analysis. In the system without nano-Ni particles, they were lepidocrocite (γ-FeOOH) and magnetite (Fe3O4) and/or maghemite (Fe2O3), however, in the systems with nano-Ni particles, they were still magnetite/maghemite but no lepidocrocite existed. The size of nano-Ni particles might affect the crystallization of corrosion products of Fe, but did not affect the species distribution of corrosion products.

  2. Aerobic biodegradation of a mixture of monosubstituted phenols in a sequencing batch reactor

    Energy Technology Data Exchange (ETDEWEB)

    Fernández, Isaac; Suárez-Ojeda, María Eugenia; Pérez, Julio; Carrera, Julián, E-mail: julian.carrera@uab.es

    2013-09-15

    Highlights: • Aerobic biodegradation of a mixture of p-nitrophenol and o-cresol is feasible. • Simultaneous biodegradation of p-nitrophenol and o-cresol was achieved at long-term. • o-Chlorophenol caused complete failure of the sequencing batch reactor. • Biomass had good settling properties although no mature granules were obtained. • p-Nitrophenol is believed to be responsible for granulation failure. -- Abstract: A sequencing batch reactor (SBR) was inoculated with p-nitrophenol-degrading activated sludge to biodegrade a mixture of monosubstituted phenols: p-nitrophenol (PNP), PNP and o-cresol; and PNP, o-cresol and o-chlorophenol. Settling times were progressively decreased to promote biomass granulation. PNP was completely biodegraded. The PNP and o-cresol mixture was also biodegraded although some transitory accumulation of intermediates occurred (mainly hydroquinone and catechol). o-Chlorophenol was not biodegraded and resulted in inhibition of o-cresol and PNP biodegradation and complete failure of the SBR within a few days. The biomass had very good settling properties when a settling time of 1 min was applied: sludge volume index (SVI{sub 5}) below 50 mL g{sup −1}, SVI{sub 5}/SVI{sub 30} ratio of 1 and average particle size of 200 μm.

  3. The adsorptive properties of powdered carbon materials with a strongly differentiated porosity and their applications in electroanalysis and solid phase microextraction.

    Science.gov (United States)

    Kuśmierek, K; Sankowska, M; Skrzypczyńska, K; Świątkowski, A

    2015-05-15

    The adsorption of 4-chlorophenol from an aqueous solution on carbonaceous materials (one carbon black and two powdered activated carbons) with a strongly differentiated porosity was investigated. The kinetic data were fitted well to the pseudo-second order model. The amount of 4-chlorophenol adsorbed at equilibrium was increased with an increase in the specific surface area of the tested materials. The adsorption isotherms were analyzed using the Langmuir and Freundlich models. The Langmuir isotherm was slightly favorable (R(2)>0.99) rather than the Freundlich isotherm (R(2)>0.98). Carbon materials were also used for the modification of carbon paste electrodes as well as for the preparation of novel solid phase microextraction fibers. The peak current of the differential pulse voltammetry curves was increased along with the amount of added carbon paste electrode modifier. The signal response was closely related to the porosity of the materials used, and increased with the increase in the specific surface area. The amount of 4-chlorophenol extracted from the samples by the solid phase microextraction fiber's surface was also correlated with the specific surface area of the tested materials. All the novel fibers were better than the commercially available fibers prepared from polidimethylosiloxane.

  4. Aerobic biodegradation of a mixture of monosubstituted phenols in a sequencing batch reactor

    International Nuclear Information System (INIS)

    Highlights: • Aerobic biodegradation of a mixture of p-nitrophenol and o-cresol is feasible. • Simultaneous biodegradation of p-nitrophenol and o-cresol was achieved at long-term. • o-Chlorophenol caused complete failure of the sequencing batch reactor. • Biomass had good settling properties although no mature granules were obtained. • p-Nitrophenol is believed to be responsible for granulation failure. -- Abstract: A sequencing batch reactor (SBR) was inoculated with p-nitrophenol-degrading activated sludge to biodegrade a mixture of monosubstituted phenols: p-nitrophenol (PNP), PNP and o-cresol; and PNP, o-cresol and o-chlorophenol. Settling times were progressively decreased to promote biomass granulation. PNP was completely biodegraded. The PNP and o-cresol mixture was also biodegraded although some transitory accumulation of intermediates occurred (mainly hydroquinone and catechol). o-Chlorophenol was not biodegraded and resulted in inhibition of o-cresol and PNP biodegradation and complete failure of the SBR within a few days. The biomass had very good settling properties when a settling time of 1 min was applied: sludge volume index (SVI5) below 50 mL g−1, SVI5/SVI30 ratio of 1 and average particle size of 200 μm

  5. Transcriptional profiling of Gram-positive Arthrobacter in the phyllosphere: induction of pollutant degradation genes by natural plant phenolic compounds.

    Science.gov (United States)

    Scheublin, Tanja R; Deusch, Simon; Moreno-Forero, Silvia K; Müller, Jochen A; van der Meer, Jan Roelof; Leveau, Johan H J

    2014-07-01

    Arthrobacter chlorophenolicus A6 is a Gram-positive, 4-chlorophenol-degrading soil bacterium that was recently shown to be an effective colonizer of plant leaf surfaces. The genetic basis for this phyllosphere competency is unknown. In this paper, we describe the genome-wide expression profile of A.chlorophenolicus on leaves of common bean (Phaseolus vulgaris) compared with growth on agar surfaces. In phyllosphere-grown cells, we found elevated expression of several genes known to contribute to epiphytic fitness, for example those involved in nutrient acquisition, attachment, stress response and horizontal gene transfer. A surprising result was the leaf-induced expression of a subset of the so-called cph genes for the degradation of 4-chlorophenol. This subset encodes the conversion of the phenolic compound hydroquinone to 3-oxoadipate, and was shown to be induced not only by 4-chlorophenol but also hydroquinone, its glycosylated derivative arbutin, and phenol. Small amounts of hydroquinone, but not arbutin or phenol, were detected in leaf surface washes of P.vulgaris by gas chromatography-mass spectrometry. Our findings illustrate the utility of genomics approaches for exploration and improved understanding of a microbial habitat. Also, they highlight the potential for phyllosphere-based priming of bacteria to stimulate pollutant degradation, which holds promise for the application of phylloremediation. PMID:24373130

  6. Role of iron species in the photo-transformation of phenol in artificial and natural seawater

    International Nuclear Information System (INIS)

    The role played by iron oxides (goethite and akaganeite) and iron(II)/(III) species as photo-sensitizers toward the transformation of organic matter was examined in saline water using phenol as a model molecule. The study was carried out in NaCl 0.7 M solution at pH 8, artificial (ASW) and natural (NSW) seawater, in a device simulating solar light spectrum and intensity. Under illumination phenol decomposition occurs in all the investigated cases. Conversely, dark experiments show that no reaction takes place, implying that phenol transformation is a light- activated process. Following the addition of Fe(II) ions to aerated solutions, Fe(II) is easily oxidized to Fe(III) and hydrogen peroxide is formed. Regardless of the addition of Fe(II) or Fe(III) ions, photo-activated degradation is mediated by Fe(III) species. Several (and different) hydroxylated and halogenated intermediates were identified. In ASW, akaganeite promotes the formation of ortho and para chloro derivatives (2- and 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol), while goethite induces the formation of 3-chlorophenol and bromophenols. Conversely, Fe(II) or Fe(III) addition causes the formation of 3- and 4-chlorophenol and 2,3- or 3,4-dichlorophenol. 4-Bromophenol was only identified when irradiating Fe(II) spiked solutions. Natural seawater sampled in the Gulf of Trieste, Italy, has been spiked with phenol and irradiated. Phenol photo-induced transformation in NSW mediated by natural photosensitizers occurs and leads to the formation of numerous halophenols, condensed products and nitrophenols. When NSW is spiked with phenol and iron oxides, Fe(II) or Fe(III), halophenols production is enhanced. A close analogy exists between Fe(III), Fe(II)/goethite in ASW and NSW products. Different halophenols production in the natural seawater samples depends on Fe(II)/goethite (above all for 3-chlorophenol, 2,3-dichlorophenol and 4-bromophenol formation) and on Fe(III) colloidal species (3

  7. Effectiveness of Rice Husk Ash in Removal of Phenolic Compounds from Aqueous Solutions, Equilibrium and Kinetics Studies

    Directory of Open Access Journals (Sweden)

    Majid Kermani

    2012-04-01

    Full Text Available Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol compounds even at low concentration can cause toxicity, health and significant taste and odor problem in drinking waters. This research focuses on understanding the sorption process and developing a cost-effective technology for the treatment of water contaminated with phenolic compounds, which are discharged into the aquatic environment from a variety of sources. In order to remove phenolic compounds from water, a new natural sorbent, rice husk ash, was developed.Materials and Methods: Removal of phenol, 2-chlorophenol and 4-chlorophenol were characterized by spectrophotometric technique at wavelengths of 269.5, 274 and 280 nm, respectively, under batch equilibrium conditions and via changing the parameters of contact time, initial pH, and initial concentration of adsorbates and dosages of sorbent. Finally, the results were analyzed by the kinetic and isotherm models.Results: in this study, the equilibrium time was found to be 240 min for full equilibration of adsorbates. Removal percent of 2-chlorophenol was lower than two others. The maximum removal of phenol, 2-CP and 4-CP was observed at an initial pH of 5. The percentage removal of these phenolic compounds increased with increasing adsorbent dose and decreasing initial concentration. In kinetics studies, correlation coefficient and ARE factor showed that the sorption of phenol (R2=0.9999, 2-chlorophenol (R2=0.9992 and 4-chlorophenol (R2=1 fitted by pseudo second order model. Isotherm studies also revealed that, Langmuirmodel for phenol (R2=0.9499, Freundlich model for 2-chlorophenol (R2=0.9659 and 4-chlorophenol (R2=0.9542 were the best choices to describe the sorption behaviors.Conclusion: Sorption process is highly dependent on the pH and it affects adsorbent surface

  8. Mycoremediation of wood and soil from an old sawmill area contaminated for decades

    Energy Technology Data Exchange (ETDEWEB)

    Valentín, Lara; Oesch-Kuisma, Hanna; Steffen, Kari T.; Kähkönen, Mika A.; Hatakka, Annele; Tuomela, Marja, E-mail: marja.tuomela@helsinki.fi

    2013-09-15

    Highlights: • We performed experiments with non-sterile soil and wood with aged contamination. • We isolated fungal strains from a saw mill site with chlorophenols contamination. •Fungal strains were screened for tolerance to native microbes and contamination. • The best fungi degraded chlorophenols and chlorinated dibenzo-p-dioxins and -furans. -- Abstract: We investigated the potential of white-rot and litter-decomposing fungi for the treatment of soil and wood from a sawmill area contaminated with aged chlorinated phenols, dibenzo-p-dioxins and furans (PCDD/F). Eight screening assays with emphasis on application of non-sterile conditions were carried out in order to select the strains with capability to withstand indigenous microbes and contamination. Nine fungi were then selected for degrading pentachlorophenol (PCP), and 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and mineralizing radiolabelled pentachlorophenol ({sup 14}C-PCP) in non-sterile soil or wood during 15 weeks of incubation. Soil indigenous microbes and fungal inoculated soil (fungal inoculum + indigenous microbes) achieved similar degradation of PCP and 2,3,4,6-TeCP and mineralization of {sup 14}C-PCP. However, the mineralization rate of {sup 14}C-PCP by indigenous microbes was much slower than that boosted by fungal inoculum. The litter-decomposing fungus (LDF) Stropharia rugosoannulata proved to be a suitable fungus for soil treatment. This fungus mineralized 26% of {sup 14}C-PCP and degraded 43% of 2,3,4,6-TeCP and 73% of PCP. Furthermore, S. rugosoannulata attained 13% degradation of PCDD/F (expressed as WHO-Toxic Equivalent). In wood, white-rot fungi grew and degraded chlorophenols better than LDF. No efficient indigenous degraders were present in wood. Interestingly, production of toxic chlorinated organic metabolites (anisoles and veratroles) by LDF in wood was negligible.

  9. Determination of phenols by flow injection and liquid chromatography with on-line quinine-sensitized photo-oxidation and quenched luminol chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wei; Danielson, Neil D

    2003-10-01

    An on-line quinine-sensitized photo-oxidation with quenched chemiluminescence (CL) detection method is developed for phenols using flow injection (FI) and liquid chromatography (LC). This detection method is based on the decrease of light emission from the luminol CL reaction due to the photo-oxidation of phenols that scavenge the photogenerated reactive oxygen species (e.g. singlet oxygen ({sup 1}O{sub 2}) and superoxide (O{sub 2}{center_dot}{sup -})). On-line photo-oxidation is achieved using a coil photo-reactor made from fluoroethylene-propylene copolymer tubing (3048 mmx0.25 mm i.d.) coiled around a mercury UV lamp. A buffer of pH 7 and a concentration of 350 {mu}M for quinine sulfate are determined optimum for the sensitized photo-oxidation. Using a carrier system flow rate of 60 {mu}l/min, calibration curves taken by FI for 10 phenolic compounds in aqueous solutions showed this decreasing sensitivity order: 4-chlorophenol, phenol, 4-nitrophenol, 3-hydroxy-L-kynurenine, 2-nitrophenol, salicylate, 3-nitrophenol, catechol, 2,4-dinitrophenol, and 2,4-dichlorophenol. This detection method using two tandem coil photo-reactors is also applied for the LC separation of phenol, 4-nitrophenol and 4-chlorophenol on an octadecyl (C18) silica LC column using acetonitrile-H{sub 2}O (40:60, v/v) as a mobile phase. The quenched CL detection limits (about 1 {mu}M or 20 pmol) for phenol and 4-chlorophenol are comparable to those for UV detection at 254 nm. Some selectivity in the quenched CL detection is evident by no interference in the FI phenol response even when benzaldehyde and phenethanol concentrations are 8 and 15 times that of phenol.

  10. A novel iron-containing polyoxometalate heterogeneous photocatalyst for efficient 4-chlorophennol degradation by H2O2 at neutral pH

    Science.gov (United States)

    Zhai, Qian; Zhang, Lizhong; Zhao, Xiufeng; Chen, Han; Yin, Dongju; Li, Jianhui

    2016-07-01

    An iron-containing polyoxometalate (FeШLysSiW) was synthesized from ferric chloride (FeIII), lysine (Lys) and silicotungstic acid (SiW), and characterized using ICP-AES, TG, FT-IR, UV-vis DRS, XRD and SEM. The chemical formula of FeШLysSiW was determined as [Fe(H2O)5(C6H14N2O2)]HSiW12O40·8H2O, with Keggin-structured SiW12O404- heteropolyanion and lysine moiety. As a heterogeneous catalyst, the as prepared FeШLysSiW showed good performance in the degradation of 4-chlorophenol by H2O2 in both the dark and irradiated systems. Under the conditions of 4-chlorophenol 100 mg/L, FeШLysSiW 1.0 g/L, H2O2 20 mmol/L and pH 6.5, 4-chlorophenol could be completely degraded in ca. 40 min in the dark and ca. 15 min upon irradiation. Prolonging the reaction time to 3 h, the TOC removal reached to ca. 71.3% in the dark and ca. 98.8% under irradiation. The catalytic activity of FeШLysSiW stems from synergetic effect of ferric iron and SiW12O404- in the catalyst, corresponding to Fenton-like catalysis and photocatalysis, respectively. The enhanced degradation of 4-CP under irradiation is due to the simultaneous oxidation of 4-CP through the Fenton-like and photocatalytic processes. The high catalytic activity of FeШLysSiW is also strongly related to the chemisorption of H2O2 on FeШLysSiW surface by hydrogen bonding, which promotes both the Fenton-like and photocatalytic processes.

  11. Effect of feeding time on the performance of a sequencing batch reactor treating a mixture of 4-CP and 2,4-DCP.

    Science.gov (United States)

    Sahinkaya, Erkan; Dilek, Filiz B

    2007-06-01

    This paper investigated the biodegradation kinetics of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) separately in batch reactors and mixed in sequencing batch reactors (SBRs). Batch reactor experiments showed that both 4-CP and 2,4-DCP began to inhibit their own degradation at 53 and 25 mg l(-1), respectively, and that the Haldane equation gave a good fit to the experimental data because r(2) values were higher than 0.98. The maximum specific degradation rates (q(m)) were 130.3 and 112.4 mg g(-1) h for 4-CP and 2,4-DCP, respectively. The values of the half saturation (K(s)) and self-inhibition constants (K(i)) were 34.98 and 79.74 mg l(-1) for 4-CP, and 13.77 and 44.46 mg l(-1) for 2,4-DCP, respectively. The SBR was fed with a mixture of 220 mg l(-1) of 4-CP, 110 mg l(-1) of 2,4-DCP, and 300 mg l(-1) of peptone as biogenic substrate at varying feeding periods (0-8h) to evaluate the effect of feeding time on the performance of the SBR. During SBR operation, in addition to self-inhibition, 4-CP degradation was strongly and competitively inhibited by 2,4-DCP. The inhibitory effects were particularly pronounced during short feeding periods because of higher chlorophenol peak concentrations in the reactor. The competitive inhibition constant (K(ii)) of 2,4-DCP on 4-CP degradation was 0.17 mg l(-1) when the reactor was fed instantaneously (0 h feeding). During longer feedings, increased removal/loading rates led to lower chlorophenol peak concentrations at the end of feeding. Therefore, in multi-substrate systems feeding time plus reaction time should be determined based on both degradation kinetics and substrate interaction. During degradation, the meta cleavage of 4-chlorocatechol resulted in accumulation of a yellowish color because of the formation of 5-chloro-2-hydroxymuconic semialdehyde (CHMS), which was further metabolized. Isolation and enrichment of the chlorophenols-degrading culture suggested Pseudomonas sp. and Pseudomonas stutzeri to be the

  12. Cadmium Telluride-Titanium Dioxide Nanocomposite for Photodegradation of Organic Substance.

    Science.gov (United States)

    Ontam, Areeporn; Khaorapapong, Nithima; Ogawa, Makoto

    2015-12-01

    Cadmium telluride-titanium dioxide nanocomposite was prepared by hydrothermal reaction of sol-gel derived titanium dioxide and organically modified cadmium telluride. The crystallinity of titanium dioxide in the nanocomposite was higher than that of pure titanium dioxide obtained by the reaction under the same temperature and pressure conditions, showing that cadmium telluride induced the crystallization of titanium dioxide. Diffuse reflectance spectrum of the nanocomposite showed the higher absorption efficiency in the UV-visible region due to band-gap excitation of titanium dioxide. The nanocomposite significantly showed the improvement of photocatalytic activity for 4-chlorophenol with UV light.

  13. Synthesis of Schiff Base Calix[4]arene Crowns

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This letter reports the synthesis of Schiff base calix[4]arene crowns containing m-xylylene phenol subunit, in which calix[4]arene Schiff base crowns 2a, 2b and 2c were formed by 1:1 condensation of calix[4]arene diamine 1 with dialdehydes (2, 6-diformyl-4-chlorophenol 3a, 2, 6-diformyl-4-methylphenol 3b, 2, 6-diformyl-4-tert-butylphenol 3c) under high dilute condition in refluxing anhydrous ethanol in 65-70% yield.

  14. Soft-tissue sarcomas and exposure to chemical substances: a case-referent study.

    OpenAIRE

    Eriksson, M.; Hardell, L; Berg, N O; T. Möller; Axelson, O

    1981-01-01

    In 1977 several patients were seen with soft-tissue sarcomas and previous exposure to phenoxy acids. This clinical observation resulted in a cases-referent (case-control) study being undertaken which showed that exposure to phenoxy acids or chlorophenols, which are chemically related, gave a roughly six-fold increase in the risk for this type of tumour. A further case-referent study of soft-tissue sarcomas has now been performed to confirm these earlier findings and also to obtain further inf...

  15. Comparison of dioxins and related compounds in the emission during the start-up procedures at a municipal waste incinerator

    Energy Technology Data Exchange (ETDEWEB)

    Gass, H.C.; Suenderhauf, W. [GfA - Gesellschaft fuer Arbeitsplatz und Umweltanalytik mbH, Berlin (Germany); Lueder, K. [MVB Muellverwertung Borsigstrasse GmbH, Hamburg (Germany); Wilken, M. [MWC - Michael Wilken Consulting, Berlin (Germany)

    2004-09-15

    In 2002/2003 we reported about PCDD/F-emissions during the start-up of a municipal waste incinerator. With primary and secondary measures during the optimization of the cold start-up phase we could show a sustainable reduction of the stack gas emissions of PCDD/F down to the range of normal operation even in the start-up phase. The measurement results of chlorophenols (ClP) and chlorobenzenes (ClB) in the flue gas (sampling point ''after boiler'') during cold-start up procedure of selected campaigns will be discussed in this paper.

  16. Effects of pentachlorophenol and some of its known and possible metabolites on different species of bacteria.

    OpenAIRE

    Ruckdeschel, G; Renner, G; Schwarz, K.

    1987-01-01

    The antibacterial activity of pentachlorophenol and 35 of its known or possible metabolites against 30 different species of bacteria was tested. In comparison with pentachlorophenol, no increase of inhibitory activity was found for any of the chlorinated anisoles tested (except for pentachloroanisole against Streptomyces spp.), 2-chlorophenol, 2,6-dichlorophenol, 2,3,6- and 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, tetrachloro-1,4- and -1,3-benzenediol (except for the 1,3-isomer again...

  17. Biodegradation of 2,4,5-trichlorophenoxyacetic acid by a pure culture of Pseudomonas cepacia.

    OpenAIRE

    Kilbane, J J; Chatterjee, D K; Karns, J S; Kellogg, S T; Chakrabarty, A M

    1982-01-01

    A pure culture of Pseudomonas cepacia, designated AC1100, that can utilize 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) as its sole source of carbon and energy was isolated. An actively growing culture of AC1100 was able to degrade more than 97% of 2,4,5-T, present at 1 mg/ml, within 6 days as determined by chloride release, gas chromatographic, and spectrophotometric analyses. The ability of AC1100 to oxidize a variety of chlorophenols and related compounds is also reported.

  18. Gas and high-performance liquid chromatography of phenols

    Energy Technology Data Exchange (ETDEWEB)

    Tesarova, E.; Pacakova, V.

    1983-05-01

    Gas (GC) and high-performance liquid chromatographic (HPLC) methods in the analysis of phenols are reviewed. Among the great number of phenolic compounds analyzed, alkylphenols, chlorophenols, dihydroxy-and trihydroxy-benzenes and biphenols are chiefly considered. The advantages and drawbacks of the methods are discussed. Relationships between the structural characteristics of phenols, the stationary phase structure, the mobile phase composition and the retention data are treated. Typical examples of the conditions for GC and HPLC analysis are summarized in tables. 276 references

  19. INVESTIGATION OF ANILINE AND PHENOLIC COMPOUNDS REMOVAL BY COOXIDATION USING AGARICUS BISPORUS TYROSINASE

    OpenAIRE

    Sevastyanov, O. V.

    2014-01-01

    An investigation of joint oxidation of aniline and phenolic compounds in aqueoussolutions using the isolated tyrosinase from Agaricus bisporus mushrooms was conducted. It is shown, that quantitative bioconversion of aniline is achieved by addition of phenol and other rapidly oxidized phenolic compounds (p-chlorophenol, o-, m-cresols)to it’s solution (0,25 mmol/dm3). Products of aniline and phenols oxidation – quinoneimines and quinones, were removed with a help of aluminium-potassium alums....

  20. Rapid dechlorination of chlorinated organic compounds by nickel/iron bimetallic system in water

    Institute of Scientific and Technical Information of China (English)

    TONG Shao-ping; WEI Hong; MA Chun-an; LIU Wei-ping

    2005-01-01

    Detoxification of chlorinated organic compounds via reaction with nickel/iron powder was implemented in aqueous solution. Compared to iron, nickel/iron bimetallic powder had higher hydrodechlorination activities for both atrazine (ATR) and p-chlorophenol (pCP); nickel/iron (2.96%, w/w) was shown to have the largest specific surface area and the optimum proportion for the dechlorination of both ATR and pCP. Electrochemical measurements showed that the adsorbed hydrogen atom on the nickel must have been the dominant reductive agent for the dechlorination of both ATR andpCP in this system.

  1. Microwave synthesis, spectral, thermal and antimicrobial studies of some Ni(II) and Cu(II) Schiff base complexes

    OpenAIRE

    Mishra, A. P.; Neha Sharma; Jain, Rajendra K.

    2012-01-01

    Bidentate and tridentate (NO), (ONO) Schiff bases have been synthesized by condensing methyl isobutyl ketone with 2-amino-4-chlorophenol and 2-hydroxy acetophenone with isonicotinic acid hydrazide. The 1:1 or 1:2 metal complexes have been prepared by interacting these Schiff bases with metal ions viz. Ni(II), Cu(II). These compounds have been synthesized by conventional as well as microwave methods and characterized by elemental analysis, FT-IR, UV-Vis, ESR, molar conductance, thermal analysi...

  2. Biomass characteristics in three sequencing batch reactors treating a wastewater containing synthetic organic chemicals

    DEFF Research Database (Denmark)

    Hu, Z.Q.; Ferraina, R.A.; Ericson, J.F.;

    2005-01-01

    compounds, chosen to represent a wide variety of chemical structures with different N, P and S functional groups. At a two-day hydraulic retention time (HRT), the oxidation-reduction potential (ORP) cycled between -100 (anoxic) and 100mV (aerobic) in the anoxic/aerobic SBR, while it remained in a range...... characteristics in the aerobic SBR and SBBR. While all reactors had very good COD removal (> 90%) and displayed nitrification, substantial nitrogen removal (74%) was only achieved in the anoxic/aerobic SBR. During the entire operational period, benzoate, theophylline and 4-chlorophenol were completely removed...

  3. 氢氧化钙在根管内封药中的应用

    Institute of Scientific and Technical Information of China (English)

    陈汉钢; 镇方汉

    2003-01-01

    @@ 通过有效的根管内封药预防根管治疗期间的急症(IAE)是提高根管治疗成功率的关键,使用传统药物樟脑对氯酚(camphorated paramon-chlorophenol,CMCP)、甲醛甲酚(formacresol,FC)、丁香油(oil of clove,OC)等进行根管内封药临床上IAE发生率较高,使治疗次数增多,患者痛苦加大.

  4. Effect of feeding time on the performance of a sequencing batch reactor treating a mixture of 4-CP and 2,4-DCP.

    Science.gov (United States)

    Sahinkaya, Erkan; Dilek, Filiz B

    2007-06-01

    This paper investigated the biodegradation kinetics of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) separately in batch reactors and mixed in sequencing batch reactors (SBRs). Batch reactor experiments showed that both 4-CP and 2,4-DCP began to inhibit their own degradation at 53 and 25 mg l(-1), respectively, and that the Haldane equation gave a good fit to the experimental data because r(2) values were higher than 0.98. The maximum specific degradation rates (q(m)) were 130.3 and 112.4 mg g(-1) h for 4-CP and 2,4-DCP, respectively. The values of the half saturation (K(s)) and self-inhibition constants (K(i)) were 34.98 and 79.74 mg l(-1) for 4-CP, and 13.77 and 44.46 mg l(-1) for 2,4-DCP, respectively. The SBR was fed with a mixture of 220 mg l(-1) of 4-CP, 110 mg l(-1) of 2,4-DCP, and 300 mg l(-1) of peptone as biogenic substrate at varying feeding periods (0-8h) to evaluate the effect of feeding time on the performance of the SBR. During SBR operation, in addition to self-inhibition, 4-CP degradation was strongly and competitively inhibited by 2,4-DCP. The inhibitory effects were particularly pronounced during short feeding periods because of higher chlorophenol peak concentrations in the reactor. The competitive inhibition constant (K(ii)) of 2,4-DCP on 4-CP degradation was 0.17 mg l(-1) when the reactor was fed instantaneously (0 h feeding). During longer feedings, increased removal/loading rates led to lower chlorophenol peak concentrations at the end of feeding. Therefore, in multi-substrate systems feeding time plus reaction time should be determined based on both degradation kinetics and substrate interaction. During degradation, the meta cleavage of 4-chlorocatechol resulted in accumulation of a yellowish color because of the formation of 5-chloro-2-hydroxymuconic semialdehyde (CHMS), which was further metabolized. Isolation and enrichment of the chlorophenols-degrading culture suggested Pseudomonas sp. and Pseudomonas stutzeri to be the

  5. Xenobiotic organic compounds in wastewater

    DEFF Research Database (Denmark)

    Eriksson, Eva; Baun, Anders; Henze, Mogens;

    2002-01-01

    Information regarding the contents of xenobiotic organic compounds (XOCs) in wastewater is limited, but it has been shown that at least 900 different compounds / compound groups could potentially be present in grey wastewater. Analyses of Danish grey wastewater revealed the presence of several...... hundred of XOCs, among them mainly originating from hygiene products: chlorophenols, detergents and phthalates. Several compounds not deriving from hygiene products were also identified e.g. flame-retardants and drugs. A environmental hazard identification showed that a large number of compounds with high...... aquatic toxicity were present and that data for environmental fate could only be retrieved for about half of the compounds....

  6. Dielectric relaxation studies of N,N-dimethyl formamide and N,N-dimethyl acetamide on complexation with phenols

    International Nuclear Information System (INIS)

    Dielectric absorption studies of H-bonded complexes of N,N-dimethyl formamide and N,N-dimethyl acetamide with p-cresol, p-chlorophenol, 2,4-dichlorophenol and p-nitrophenol in benzene have been made at 308 K using 9.37 GHz dielectric relaxation set up. The validity of the single frequency equation of Higasi et al. for multiple relaxation time τ(1) is found to be function of the hydrogen bonding strength of the phenolic hydrogen, whereas the group rotation relaxation time τ(2) is a function of the steric interactions of the proton donor. The relaxation time is maximum at 50:50 mol% ratio

  7. Thermodynamic study of adsorption of phenolic compounds onto Amberlite XAD-4 polymeric adsorbents and its acetylized derivative MX-4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Adsorption equilibrium isotherms of phenolic compounds,phenol, p-cresol, p-chlorophenol and p-nitrophenol, from aqueoussolutions by Amberlite XAD-4 polymeric adsorbent and its acetylizedderivative MX-4 within temperature range of 283-323K were obtainedand fitted to the Freundlich isotherms. The capacities ofequilibrium adsorption for all four phenolic compounds from theiraqueous solutions increased around 20% on the acetylized resin,which may be contributed to the specific surface area and thepartial polarity on the network. Estimations of the isosteric enthalpy, free energy , and entropy for the adsorption process arereported.

  8. CURE CHARACTERISTICS OF HYDROXYL TERMINATED POLYBUTADIENE PREPOLYMER WITH BLOCKED TOLUENE DIISOCYANATE-Ⅱ

    Institute of Scientific and Technical Information of China (English)

    Prathima Kamath; M. Srinivasan; V. N. Krishnamurthy

    1994-01-01

    Cure characteristics of hydroxyl terminated polybutadiene (HTPB) prepolymer with a variety of blocked toluene diisocyanate (TDI) in the presence of triethylamine (TEA) and chloroacetic acid catalyst are reported. Phenol, thiophenol, p-chlorophenol, p-nitrophenol,p-cresol , resorcinol, naphthols, caprolactam and butylated-hydroxytoluene were used as blocking agents. Viscosity measurements have been carried out using a mixture of HTPB and blocked TDI in cyclohexanone in the presence of the catalysts at 50℃ and 60℃ using Haake rotational viscometer. Viscosity measurements have also been carried out with 50% solids such as ammonium sulphate along with HTPB and TDI adduct.

  9. Impact of continuous and intermittent supply of electric assistance on high-strength 2,4-dichlorophenol (2,4-DCP) degradation in electro-microbial system.

    Science.gov (United States)

    Cao, Zhanping; Zhang, Minghui; Zhang, Jingli; Zhang, Hongwei

    2016-07-01

    The high-strength 2,4-DCP, which exists in two states: dissolved and colloidal, was studied by a continuously electro-microbial system (CEMS) and an intermittently electro-microbial system (IEMS). The hydrolysis rate of colloidal 2,4-DCP in the IEMS without electric assistance was much higher than that in the CEMS. However, the degradation rate of the dissolved 2,4-DCP and the dissolved intermediates (2-chlorophenol and 4-chlorophenol) in the IEMS without electric assistance were much lower than that in the CEMS. By adjusting the intermittent operation mode, the degradation time of 2,4-DCP was shortened greatly. Microbial characteristics in the CEMS and the IEMS were different. The correlation analysis for the main factors affecting the hydrolysis was performed by SPSS, and it was found that the correlation coefficient (rp) was -0.912 for extracellular polymeric substances (EPS) content, 0.823 for zeta potential and 0.632 for relative hydrophobicity, respectively. PMID:27092992

  10. Detection of phenolic compounds using impedance spectroscopy measurements.

    Science.gov (United States)

    Olivati, Clarissa A; Riul, Antonio; Balogh, Débora T; Oliveira, Osvaldo N; Ferreira, Marystela

    2009-01-01

    Langmuir-Blodgett (LB) and layer-by-layer films (LbL) of a PPV (p-phenylenevinylene) derivative, an azo compound and tetrasulfonated phthalocyanines were successfully employed as transducers in an "electronic tongue" system for detecting trace levels of phenolic compounds in water. The choice of the materials was based on their distinct electrical natures, which enabled the array to establish a fingerprint of very similar liquids. Impedance spectroscopy measurements were taken in the frequency range from 10 Hz to 1 MHz, with the data analysed with principal component analysis (PCA). The sensing units were obtained from five-layer LB films of (poly[(2-methoxy-5-n-hexyloxy)-p-phenylenevinylene]), OC(1)OC(18)-PPV (poly(2-methoxy,5-(n-octadecyl)-p-phenylenevinylene)), DR (HEMA-co-DR13MA (poly-(hydroxyethylmethacrylate-co-[4'-[[2-(methacryloyloxy)-ethyl]ethylamino]-2-chloro-4-nitroazobenzene]))) and five-bilayer LbL films of tetrasulfonated metallic phthalocyanines deposited onto gold interdigitated electrodes. The sensors were immersed into phenol, 2-chloro-4-methoxyphenol, 2-chlorophenol and 3-chlorophenol (isomers) solutions at 1 x 10(-9) mol L(-1), with control experiments carried out in ultra pure water. Samples could be distinguished if the principal component analysis (PCA) plots were made with capacitance values taken at 10(3) Hz, which is promising for detection of trace amounts of phenolic pollutants in natural water. PMID:18408956

  11. Self-bioremediation of cork-processing wastewaters by (chloro)phenol-degrading bacteria immobilised onto residual cork particles.

    Science.gov (United States)

    del Castillo, I; Hernández, P; Lafuente, A; Rodríguez-Llorente, I D; Caviedes, M A; Pajuelo, E

    2012-04-15

    Cork manufacturing is a traditional industry in Southern Europe, being the main application of this natural product in wine stoppers and insulation. Cork processing begins at boiling the raw material. As a consequence, great volumes of dark wastewaters, with elevated concentrations of chlorophenols, are generated, which must be depurated through costly physicochemical procedures before discarding them into public water courses. This work explores the potential of bacteria, isolated from cork-boiling waters storage ponds, in bioremediation of the same effluent. The bacterial population present in cork-processing wastewaters was analysed by DGGE; low bacterial biodiversity was found. Aerobic bacteria were isolated and investigated for their tolerance against phenol and two chlorophenols. The most tolerant strains were identified by sequencing 16S rDNA. The phenol-degrading capacity was investigated by determining enzyme activities of the phenol-degrading pathway. Moreover, the capacity to form biofilms was analysed in a microtitre plate assay. Finally, the capacity to form biofilms onto the surface of residual small cork particles was evaluated by acridine staining followed by epifluorescence microscopy and by SEM. A low-cost bioremediation system, using phenol-degrading bacteria immobilised onto residual cork particles (a by-product of the industry) is proposed for the remediation of this industrial effluent (self-bioremediation).

  12. IMPACT OF C STAGE VARIABLES ON THE TOXICITY DURING PAPER PRODUCTION IN MILLS

    Directory of Open Access Journals (Sweden)

    Divya Prakash

    2013-09-01

    Full Text Available Chlorinated phenolics are formed during chlorination stage of pulp bleaching. These phenolics are dissolved in the alkaline extraction stage. The bleach plant effluent therefore contains these compounds in appreciable amount. As these chlorophenolics are highly toxic in nature, efforts have been made to reduce their concentration by changing the bleaching parameters. In the present studies experiments were conducted with bamboo pulp employing CEH sequence of bleaching under varying conditions. The effect of changing the chlorination stage parameters like pH, temperature, pulp consistency and distribution of bleaching chemicals between C and H was changed. The effluent parameters and pulp characteristics have also been determined. The results show that the amount of all categories of chlorinated phenolics are reduced by increasing the pH (1.5–4.0, decreasing temperature (35-150C and all chlorophenolics are decreased by decreasing the consistency (4-2% and C:H ratio (65:35 to 45:55.

  13. A comparative study of proton transport properties of metal (IV) tungstates and their organic derivatives

    Indian Academy of Sciences (India)

    Heemanshu Patel; Alpana Parikh; Uma Chudasama

    2005-04-01

    New hybrid inorgano–organic materials were synthesized by anchoring organic moieties, ortho chlorophenol and para chlorophenol onto metal (IV) tungstates viz. tin tungstate (SnW), titanium tungstate (TiW) and zirconium tungstate (ZW) to give SnWoCP, SnWpCP, TiWoCP, TiWpCP, ZWoCP and ZWpCP, respectively. The materials were characterized for elemental analysis, thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. Chemical resistivity of these materials were assessed in several acidic, basic and organic media. Further, the study of transport properties of these materials has been explored by measuring proton conductivity at different temperatures in the range 30–175°C using HP4192A impedance analyser over a frequency range 5 Hz–13 MHz at a signal level below 1 V. Based on the specific conductance data and Arrhenius plots, a suitable mechanism was proposed and conductance performance of derivatized and nonderivatized materials compared.

  14. Dechlorination pathways of diverse chlorinated aromatic pollutants conducted by Dehalococcoides sp. strain CBDB1

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Gui-Ning [School of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006 (China); Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 (United States); School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Tao, Xue-Qin [School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225 (China); Huang, Weilin [Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 (United States); Dang, Zhi, E-mail: chzdang@scut.edu.cn [School of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Li, Zhong [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Liu, Cong-Qiang [The State Key Lab of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2010-05-15

    Dechlorination of chlorinated aromatic pollutants (CAPs) has become a major issue in recent decades. This paper reported a theoretical indicator for predicting the reductive dechlorination pathways of polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes and chlorophenols transformed by Dehalococcoides sp. strain CBDB1. Density functional theory (DFT) calculations were carried out at the B3LYP/6-31G(d) level for all related CAPs and Mulliken atomic charges on chlorine atoms (Q{sub Cl(n)}) were adopted as the probe of the dechlorination reaction activity. Q{sub Cl(n)} can consistently indicate the main dechlorination daughter products of PCDDs, chlorobenzenes and chlorophenols conducted by strain CBDB1. The dechlorination reaction favors elimination of the chlorine atoms having greater Q{sub Cl(n)} values. The chlorine atom with the greatest Q{sub Cl(n)} value tends preferentially to be eliminated, whereas the chlorine atom with the smallest Q{sub Cl(n)} value tends unlikely to be eliminated or does not react at all. For a series of compounds having similar structure, the maximal Q{sub Cl(n)} of each molecular can be used to predict the possibility of its daughter product(s). In addition, the difference ({Delta}Q{sub Cl(n)}) between the maximal Q{sub Cl(n)} and the next maximal Q{sub Cl(n)} of the same molecule can be used to assess the possibility of formation of multiple dechlorination products.

  15. Automated multisyringe stir bar sorptive extraction using robust montmorillonite/epoxy-coated stir bars.

    Science.gov (United States)

    Ghani, Milad; Saraji, Mohammad; Maya, Fernando; Cerdà, Víctor

    2016-05-01

    Herein we present a simple, rapid and low cost strategy for the preparation of robust stir bar coatings based on the combination of montmorillonite with epoxy resin. The composite stir bar was implemented in a novel automated multisyringe stir bar sorptive extraction system (MS-SBSE), and applied to the extraction of four chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol) as model compounds, followed by high performance liquid chromatography-diode array detection. The different experimental parameters of the MS-SBSE, such as sample volume, selection of the desorption solvent, desorption volume, desorption time, sample solution pH, salt effect and extraction time were studied. Under the optimum conditions, the detection limits were between 0.02 and 0.34μgL(-1). Relative standard deviations (RSD) of the method for the analytes at 10μgL(-1) concentration level ranged from 3.5% to 4.1% (as intra-day RSD) and from 3.9% to 4.3% (as inter-day RSD at 50μgL(-1) concentration level). Batch-to-batch reproducibility for three different stir bars was 4.6-5.1%. The enrichment factors were between 30 and 49. In order to investigate the capability of the developed technique for real sample analysis, well water, wastewater and leachates from a solid waste treatment plant were satisfactorily analyzed. PMID:27062720

  16. Self-bioremediation of cork-processing wastewaters by (chloro)phenol-degrading bacteria immobilised onto residual cork particles.

    Science.gov (United States)

    del Castillo, I; Hernández, P; Lafuente, A; Rodríguez-Llorente, I D; Caviedes, M A; Pajuelo, E

    2012-04-15

    Cork manufacturing is a traditional industry in Southern Europe, being the main application of this natural product in wine stoppers and insulation. Cork processing begins at boiling the raw material. As a consequence, great volumes of dark wastewaters, with elevated concentrations of chlorophenols, are generated, which must be depurated through costly physicochemical procedures before discarding them into public water courses. This work explores the potential of bacteria, isolated from cork-boiling waters storage ponds, in bioremediation of the same effluent. The bacterial population present in cork-processing wastewaters was analysed by DGGE; low bacterial biodiversity was found. Aerobic bacteria were isolated and investigated for their tolerance against phenol and two chlorophenols. The most tolerant strains were identified by sequencing 16S rDNA. The phenol-degrading capacity was investigated by determining enzyme activities of the phenol-degrading pathway. Moreover, the capacity to form biofilms was analysed in a microtitre plate assay. Finally, the capacity to form biofilms onto the surface of residual small cork particles was evaluated by acridine staining followed by epifluorescence microscopy and by SEM. A low-cost bioremediation system, using phenol-degrading bacteria immobilised onto residual cork particles (a by-product of the industry) is proposed for the remediation of this industrial effluent (self-bioremediation). PMID:22265252

  17. Purification of a new isoform of laccase from a Marasmius quercophilus strain isolated from a cork oak litter (Quercus suber L).

    Science.gov (United States)

    Farnet, A M; Criquet, S; Pocachard, E; Gil, G; Ferre, E

    2002-01-01

    A new isoform of laccase from Marasmius quercophilus is described in this study. The strain of this white-rot fungus was isolated for the first time on a cork oak litter. This isoform exhibited certain common properties of laccases (a molecular weight of 65 Kda, an optimum pH of 6.2 with syringaldazine). But this laccase has also particularly novel features: the best activity measured was observed at high temperatures (80 C) and this isoform was not inhibited with EDTA. Furthermore, this induced laccase was able to transform most of the aromatic compounds tested without the addition of mediators to the reaction mixture, and the transformation of certain chlorophenols (2-chlorophenol and 2,4-dichlorophenol) by a laccase isoform from M. quercophilus is reported here for the first time. We also demonstrate the importance of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) as a mediator since it allowed veratryl alcohol and p-hydroxybenzoic acid transformation. Moreover, new products of transformation were observed using the combination of ABTS with this isoform of laccase. PMID:21156546

  18. Phosphorylated multiwalled carbon nanotube-cyclodextrin polymer: synthesis, characterisation and potential application in water purification.

    Science.gov (United States)

    Mamba, G; Mbianda, X Y; Govender, P P

    2013-10-15

    Multiwalled carbon nanotubes were synthesised by the nebulised spray pyrolysis method and purified to remove amorphous carbon and fullerenes. The purified multiwalled carbon nanotubes were oxidised using a 3:1 H2SO4/HNO3 mixture to introduce carboxylic groups and to a smaller extent hydroxyl groups on the walls of the carbon nanotubes. Subsequently, the oxidised carbon nanotubes were chlorinated using oxalyl chloride to generate acyl chloride groups through which phosphorylation took place. 4-Aminophenyl methylphosphonate was attached to the multiwalled carbon nanotubes via an amidation reaction. FT-IR and XPS confirmed the presence of PO, PO and PCP functional groups in the phosphorylated carbon nanotubes. Polymerisation of the phosphorylated carbon nanotubes with cyclodextrins was achieved using hexamethylene diisocyanate as a bifunctional linker. Surface morphology of the polymer was investigated by SEM while FT-IR was used to confirm the polymerisation reaction. Moreover, the thermal stability of the polymer was probed using TGA while BET was employed to determine the surface area and pore volume of the polymer. Furthermore, the polymer was tested for the removal of cobalt and 4-chlorophenol from synthetic aqueous solutions of the pollutants. The polymer displayed potential as an adsorbent for both cobalt and 4-chlorophenol.

  19. Regeneration strategies of polymers employed in ex-situ remediation of contaminated soil: Bioregeneration versus solvent extraction.

    Science.gov (United States)

    Mosca Angelucci, Domenica; Tomei, M Concetta

    2015-08-15

    In this study we evaluated the feasibility of two regeneration strategies of contaminated polymers employed for ex-situ soil remediation in a two-step process. Soil decontamination is achieved by sorption of the pollutants on the polymer beads, which are regenerated in a subsequent step. Tested soil was contaminated with a mixture of 4-chlorophenol and pentachlorophenol, and a commercial polymer, Hytrel, has been employed for extraction. Removal efficiencies of the polymer-soil extraction are in the range of 51-97% for a contact time ≤ 24 h. Two polymer regeneration strategies, solvent extraction and biological regeneration (realized in a two-phase partitioning bioreactor), were tested and compared. Performance was assessed in terms of removal rates and efficiencies and an economic analysis based on the operating costs has been performed. Results demonstrated the feasibility of both regeneration strategies, but the bioregeneration was advantageous in that provided the biodegradation of the contaminants desorbed from the polymer. Practically complete removal for 4-chlorophenol and up to 85% biodegradation efficiency for pentachlorophenol were achieved. Instead, in the solvent extraction, a relevant production (184-831 L kg(pol)(-1)) of a highly polluted stream to be treated or disposed of is observed. The cost analysis of the two strategies showed that the bioregeneration is much more convenient with operating costs of ∼12 €/kg(pol) i.e. more than one order of magnitude lower in comparison to ∼233 €/kg(pol) of the solvent extraction. PMID:26074469

  20. The removal of chlorinated organic herbicide in water by gamma-irradiation

    International Nuclear Information System (INIS)

    In this study, the radiation-induced degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in aqueous solution was studied under various conditions as a function of irradiation dose in the absence and presence of hydrogen peroxide. The obtained data confirmed that largest yield of radiolytic degradation is obtained in oxidation processes/ionizing radiation, where oxidation is carried out with hydroxyl radicals. For complete degradation of 50 ppm 2,4-D, a required dose was lower in the presence of hydrogen peroxide. The formed major toxic phenolic intermediates were 2,4-dichlorophenol (2,4-DCP) and 4-chlorophenol (4-CP). The chemical analysis of the 2,4-D and the intermediates resulted from the radiolytic degradation were performed using a gas chromatography associated to mass spectrometry (GC-MS) with ion trap detector (ITD) and ion chromatography (IC). The formation of chlorophenols in addition to chloride, formaldehyde and carboxylic acids was studied as a function of absorbed dose. (author)