Using anti-corrosive paints on ships

Energy Technology Data Exchange (ETDEWEB)

Smith, J

1969-02-07

Anit-corrosive paints on the outside of ship's hulls fall into 3 groups: the area below the water, the boot- topping area at the waterline, and the weatherwork including the hull and superstructure. Typical formulations of primer and paint are given for use in each section. Anti-corrosion paints must always be considered in conjunction with the kind and amount of surface preparation that can be given. The requirement for faster descaling techniques and higher standards of surface preparation has led to the introduction of automated centrifugal abrasive blasting machines for all new plates and sections. If it is not possible to remove old coatings by abrasive blasting, then the traditional method of chipping followed by wire brushing must be used. The removal of mill scale by abrasive blasting can produce a clean metal surface which is liable to rapid corrosion unless it is painted immediately. A pre-fabrication or shop primer is used which is normally applied by airless spray equipment synchronized with the sand blasting machinery.

Anti-corrosion coatings in mine construction

Energy Technology Data Exchange (ETDEWEB)

Muchnik, P.I.; Plishevoi, A.N.; Semikina, N.I.

1984-04-01

This paper describes developments in methods used to protect mine equipment against corrosion. Paint/varnish materials such as EhF-1219 will protect metallic structures above ground for 8 years with a single coat (100-120 microns), and 2 coats will protect underground equipment (even in wet conditions) for up to 10 years. Various rust modifiers are also in use, based on oak tanning extract, oxalic acid and orthophosphoric acid in combination with zinc or aluminium phosphate. VNIIOMShS has developed an improved rust modifier which is applied with brush or spray and left to dry for 24 hours at 18-23 C. Experience has shown that paint/varnish coatings may be employed to give protection on equipment with a planned service life of up to 25 years, while for longer service lives zinc or combined coatings are preferred. VNIIOMShS has also developed methods for applying paint/varnish materials on tall structures without suspended gear, and for the preparation of surfaces for anti-corrosion coatings. (In Russian)

A New Detecting Technology for External Anticorrosive Coating Defects of Pipelines Based on Ultrasonic Guided Wave

Science.gov (United States)

Liu, Shujun; Zuo, Yonggang; Zhang, Zhen

2018-01-01

The external anticorrosive coating is the shelter for preventing steel pipelines from Corrosive damage. A number of pipelines face severe corrosive problems for the performance decrease of the coating, especially during long-term services, which usually led to safety accidents. To solve the detection problem about the defect of anticorrosive layer for pipeline, a new detection method for anticorrosive layer of pipelines based on Ultrasonic Guided Wave was proposed in the paper. The results from the investigation show a possibility of using the Ultrasonic Guided Wave method for detecting the damage of pipeline’s External Anticorrosive Coating.

Qualification of anticorrosive coatings in nuclear vessels

International Nuclear Information System (INIS)

Perez Flores, C.

1985-01-01

Test qualifications of the behavior of anticorrosive coating systems used in nuclear vessels in service and under the accident conditions of radiation decontamination, steam chemical resistance, thermal conductivity, weathering accelerated aging are presented and discussed. (author)

Exopolysaccharides (EPS) as anti-corrosive additives for coatings

NARCIS (Netherlands)

Scheerder, J.; Breur, R.; Slaghek, T.; Holtman, W.; Vennik, M.; Ferrari, G.

2012-01-01

Exopolysaccharides (EPS) are a class of renewable polymers that show interesting anti-corrosive properties and could potentially be used as an alternative for zinc phosphates. When combined with a waterborne styrene-acrylic polymer dispersion (SA-1), exopolysaccharides were shown to give an

Facile fabrication of core-shell Pr6O11-ZnO modified silane coatings for anti-corrosion applications

Science.gov (United States)

Jeeva Jothi, K.; Palanivelu, K.

2014-01-01

In this work, we have developed a facile and inexpensive method to fabricate anti-corrosive and hydrophobic surface with hierarchical micro and nano structures. We demonstrate for the first time the use of praseodymium oxide doped zinc oxide (Pr6O11-ZnO) nanocomposites loaded in a hybrid sol-gel (SiOx/ZrOx) layer, to effectively protect the underlying steel substrate from corrosion attack. The influence of Pr6O11-ZnO gives the surprising aspects based on active anti-corrosion and hydrophobic coatings. The spherical SiO2 particles have been successfully coated with Pr6O11-ZnO layer through sol-gel process. The resulted SiO2@Pr6O11-ZnO core-shell was characterized by Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS). The barrier properties of the intact coatings were assessed by Electrochemical Impedance Spectroscopy (EIS). The fabrication of SiO2@Pr6O11-ZnO shows dual properties of hydrophobic and anti-corrosion micro/nanostructured sol-gel coatings follows a single/simple step coating procedure. This study has led to a better understanding factor influencing the anti-corrosion performance with embedded nanocomposites. These developments are particularly for silane network@ Pr6O11-ZnO for self-healing and self-cleaning behavior which can be designed for new protective coating system.

Study on performance of waterborne anticorrosive coatings on steel rebars

Science.gov (United States)

Ramaswamy, S. N.; Varalakshmi, R.; Selvaraj, R.

2017-12-01

Durability of reinforced cement concrete structures is mainly affected by corrosion of steel reinforcements. In order to protect the reinforcing bars from corrosion and to enhance the lifetime of reinforced cement concrete structural members, anticorrosive treatment to steel is of prime importance. Conventional coatings are solvent based. In this study, water based Latex was used to formulate anticorrosive coating. Latex is applied to steel specimen substrates such as plates and rods and their mechanical properties such as flexibility, abrasion, bendability, adhesive strength, impact resistance, etc. were studied. It was inferred that coating containing latex, micro silica, zinc phosphate, ferric oxide, aluminum oxide, titanium oxide and silica fume was found to possess more corrosion resistance under marine exposure conditions.

Anticorrosive coating of SixOyCz on metallic substrates applied with the plasma CVD technique

International Nuclear Information System (INIS)

Perillo, P; Lasorsa, C; Versaci, R

2006-01-01

This work deals with the production of anticorrosive coatings of Si x O y C z on metallic substrates by PECVD (Plasma Enhanced Chemical Vapor Deposition) in a two layer coating, with a gaseous mixture using methyltrimethoxysilane (Z6070) with the contribution of O 2 and methane as reactive gases. The process involves two steps, the first with the substrate thermalized to 500 o C and the second step with the substrate at room temperature. In the first step the process is carried out with the mixture of O 2 and Z6070, in the second step methane is added to the mixture of the plasma forming gases. The coatings were carried out on AISI 410 stainless steel, AISI M2 steel, titanium and AA6061 aluminum substrates. This work presents the preliminary results of the electrochemical evaluation and the mechanical properties of the coating. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS/ESCA ), and scanning electron microscopy were used for this study. Electrochemical techniques were used to study the reaction to the corrosion of the coatings. Potentiodynamic polarization curves were prepared in a solution of 5% H 2 SO 4 and in NaCl 0,1M. The tests were undertaken at room temperature. This process is presented as an alternative to the conventional immersion processes by the sol-gel method, which produces the polymerization of the reagent as a result of the effect of the oxygen from the environment, while the plasma process produces very different chemical reactions in the center of the plasma itself with coatings also different (CW)

Anticorrosion and halobios control for tidal power generating units

International Nuclear Information System (INIS)

Shen, J C; Ding, L X

2012-01-01

The anticorrosion and halobios control is the key techniquesrelated to the safety and durability of tidal power generating units. The technique of material application, antifouling coating and cathodic protection are often adopted. The technical research, application, updating and development are carried on Jiangxia Tidal Power Station, which is based on the old Unit 1-Unit 5 operated for nearly 30 years, and the new Unit 6 operated in 2007. It is found that stainless steeland the antifouling coating used in Unit 1- Unit 5 are very effective, but cathodic protection is often likely to fail because of the limitation of structure and installation. Analyses and studies for anticorrosion and halobios control techniques of tidal power generating units according to theory, experience and actual effects have been done, which can be for reference to the tidal power station designers and builders.

Influence on the anticorrosive properties of the use of erbium (III) trifluoromethanesulfonate as initiator in an epoxy powder clearcoat

International Nuclear Information System (INIS)

Garcia, S.J.; Suay, J.

2007-01-01

New low curing temperature epoxy powder coatings cured cationically by the use of erbium (III) trifluoromethanesulfonate as initiator have been formulated. Their curing kinetics and anticorrosive properties have been studied and compared with a system commonly used in industry (o-tolylbiguanide/epoxy resin). Three different tests of anticorrosive properties (EIS, AC/DC/AC, and salt fog spray) have been used together with an adherence test, in order to establish the optimal system. Results show that a system employing 1 phr of erbium triflate presents good anticorrosive properties. The technique AC/DC/AC has shown its ability to evaluate properly, much faster, and in accordance to anticorrosive properties results' of powder coatings obtained by other techniques

Influence on the anticorrosive properties of the use of erbium (III) trifluoromethanesulfonate as initiator in an epoxy powder clearcoat

Energy Technology Data Exchange (ETDEWEB)

Garcia, S.J. [Centro de Biomateriales, Universitat Politecnica de Valencia, Camino de Vera s/n, E-46071 Valencia (Spain)]. E-mail: sangares@upvnet.upv.es; Suay, J. [Centro de Biomateriales, Universitat Politecnica de Valencia, Camino de Vera s/n, E-46071 Valencia (Spain)

2007-08-15

New low curing temperature epoxy powder coatings cured cationically by the use of erbium (III) trifluoromethanesulfonate as initiator have been formulated. Their curing kinetics and anticorrosive properties have been studied and compared with a system commonly used in industry (o-tolylbiguanide/epoxy resin). Three different tests of anticorrosive properties (EIS, AC/DC/AC, and salt fog spray) have been used together with an adherence test, in order to establish the optimal system. Results show that a system employing 1 phr of erbium triflate presents good anticorrosive properties. The technique AC/DC/AC has shown its ability to evaluate properly, much faster, and in accordance to anticorrosive properties results' of powder coatings obtained by other techniques.

Creation of anticorrosion coatings for contact devices of rectifying columns

Directory of Open Access Journals (Sweden)

KATAMANOV Vladimir Leonidovich

2018-02-01

Full Text Available Today the main corrosion protection methods applied in contact devices of rectifying oil processing equipment, in particular, in mesh nozzles made of stainless steel, under relatively high temperatures (150–250оC and in the presence of aggressive components in oil raw materials (hydrogen sulfide, sulfides, mercaptans, other sulphurous compounds, chloride ions, organochlorine connections, water are to use special alloys as protecting covers as well as corrosion inhibitors that reduce corrosion action of hostile environment. At the same time, the disadvantages of the majority of these methods concern high operational costs, insufficient efficiency or protection ability designed only for a certain factor, but not for combination of them. In this regard corrosion resistance of mesh contact devices made of stainless steel (brand SUS 321 has been studied on three types of samples: alloy wire, welded grid, thin leaf. Titanium nitride (TiN and metallic coatings from nickel (Ni, titanium (Ti and chrome (Cr were used as anticorrosion coatings for the mentioned samples. These coverings were applied on samples in two ways: by means of electrolytic method and vacuum ion-plasma dusting. It was determined that optimal coating thickness is 10–15 microns as it is the thickness at which the produced films possess sufficient plasticity and do not exfoliate from the surface of the corresponding corrosion-proof alloy. The research of corrosion of samples of stainless steel SUS 321 with applied coverings and without them was performed by immersing the samples into compositions that contain oil as well as into the modeling hostile oil-containing environment. As a result of the conducted researches it was determined that the protecting covers of chrome and titanium nitride applied with vacuum ion-plasma dusting method are the most effective coatings from the point of view of anticorrosive protection for mesh contact devices of stainless steel used in rectifying

Effect of pretreating technologies on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens

Energy Technology Data Exchange (ETDEWEB)

Zhang, Pengjie [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Earth-Panda Advance Magnetic Material Co. Ltd., Hefei (China); Anhui Province Key Laboratory of Rare Earth Permanent Magnet Materials, Hefei (China); State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co., Ltd.), Hefei (China); Xu, Guangqing, E-mail: gqxu1979@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Liu, Jiaqin [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Yi, Xiaofei [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Earth-Panda Advance Magnetic Material Co. Ltd., Hefei (China); Anhui Province Key Laboratory of Rare Earth Permanent Magnet Materials, Hefei (China); State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co., Ltd.), Hefei (China); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Chen, JingWu [Earth-Panda Advance Magnetic Material Co. Ltd., Hefei (China); Anhui Province Key Laboratory of Rare Earth Permanent Magnet Materials, Hefei (China); State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co., Ltd.), Hefei (China)

2016-02-15

Graphical abstract: Zn coated NdFeB specimens pretreated with different technologies possess different adhesive strengths and anticorrosion properties. And the combined technology of sandblasting and pickling (5 s) achieves the best comprehensive performance. - Highlights: • Zn coated NdFeB specimens are achieved with different pretreating technologies. • Combined technology possesses the highest adhesive strength. • Combined technology possesses excellent anticorrosion property. - Abstract: Zinc coated NdFeB specimens were prepared with different pretreating technologies, such as polishing, pickling (50 s), sandblasting and combined technology of sandblasting and pickling (5 s). Morphologies of the NdFeB substrates pretreated with different technologies were observed with a scanning electron microscope equipped with an energy dispersive spectrometer and an atomic force microscope. The tensile test was performed to measure the adhesive strength between Zn coating and NdFeB substrate. The self-corrosion behavior of the NdFeB specimen was characterized by potentiodynamic polarization curve. The anticorrosion properties of Zn coated NdFeB specimens were characterized by neutral salt spray tests. The pretreating technologies possess obvious impact on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens. Combined pretreating technology of sandblasting and pickling (5 s) achieves the highest adhesive strength (25.56 MPa) and excellent anticorrosion property (average corrosion current density of 21 μA/cm{sup 2}) in the four pretreating technologies. The impacting mechanisms of the pretreating technology on the adhesive strength and anticorrosion properties are deeply discussed.

Effect of pretreating technologies on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens

International Nuclear Information System (INIS)

Zhang, Pengjie; Xu, Guangqing; Liu, Jiaqin; Yi, Xiaofei; Wu, Yucheng; Chen, JingWu

2016-01-01

Graphical abstract: Zn coated NdFeB specimens pretreated with different technologies possess different adhesive strengths and anticorrosion properties. And the combined technology of sandblasting and pickling (5 s) achieves the best comprehensive performance. - Highlights: • Zn coated NdFeB specimens are achieved with different pretreating technologies. • Combined technology possesses the highest adhesive strength. • Combined technology possesses excellent anticorrosion property. - Abstract: Zinc coated NdFeB specimens were prepared with different pretreating technologies, such as polishing, pickling (50 s), sandblasting and combined technology of sandblasting and pickling (5 s). Morphologies of the NdFeB substrates pretreated with different technologies were observed with a scanning electron microscope equipped with an energy dispersive spectrometer and an atomic force microscope. The tensile test was performed to measure the adhesive strength between Zn coating and NdFeB substrate. The self-corrosion behavior of the NdFeB specimen was characterized by potentiodynamic polarization curve. The anticorrosion properties of Zn coated NdFeB specimens were characterized by neutral salt spray tests. The pretreating technologies possess obvious impact on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens. Combined pretreating technology of sandblasting and pickling (5 s) achieves the highest adhesive strength (25.56 MPa) and excellent anticorrosion property (average corrosion current density of 21 μA/cm 2 ) in the four pretreating technologies. The impacting mechanisms of the pretreating technology on the adhesive strength and anticorrosion properties are deeply discussed.

Graphene coating for anti-corrosion and the investigation of failure mechanism

International Nuclear Information System (INIS)

Zhu, Y X; Duan, C Y; Chen, Y F; Wang, Y; Liu, H Y

2017-01-01

Graphene produced by chemical vapor deposition (CVD) methods has been considered as a promising corrosion prevention layer because of its exceptional structure and impermeability. However, the anti-corrosion performance and the failure mechanism are still controversial. In this study, graphene layers with different quality levels, crystallite sizes, and layer numbers were prepared on the surface of Cu by a CVD process. The effects of grain boundaries (GBs) on the failure of graphene layers to provide adequate protection were investigated in detail by combining graphene transfer techniques, computation, and anti-corrosion measurements. Our results reveal that corrosion rates decrease marginally upon the increase of graphene layer number, and this rather weak dependence on thickness likely arises from the aligned nature of the GBs in CVD-grown few-layer graphene. This problem can potentially be overcome by layer-by-layer graphene transfer technique, in which corrosion is found to be arrested locally when transferred graphene is present on top of the as-grown graphene. However, this advantage is not reflected in corrosion studies performed on large-scale samples, where cracks or imperfect interfaces could offset the advantages of GB misalignment. With improvements in technology, the layer-by-layer assembly technique could be used to develop an effective anti-corrosion barrier. (paper)

Effect of nitrogen-doped carbon dots on the anticorrosion properties of waterborne epoxy coatings

Science.gov (United States)

Ren, Siming; Cui, Mingjun; Zhao, Haichao; Wang, Liping

2018-06-01

In this work, nitrogen-doped carbon dots (NCDs) are prepared by solvothermal method and the effect of NCDs on the anticorrosion property of waterborne epoxy (EP) is investigated. Scanning probe microscopy results show that the size of the NCDs is about 4–6 nm. In addition, the anticorrosion property of NCD-incorporated waterborne epoxy coatings is investigated via electrochemical techniques and scanning electron microscopy. Electrochemical results demonstrate that the impedance modulus of 2.0% NCDs/EP is 364 times higher than that of blank EP after 800 h of immersion, indicating significant enhancement in the anticorrosion property of waterborne epoxy coating. The reason is that NCDs with lots of surface functional groups can connect with waterborne epoxy to suppress enlargement of the pores, and reduce the diffusion of oxygen in the coating, thus cutting off the connection between the substrate and oxygen, and delaying corrosion of the substrate.

Halloysite tubes as nanocontainers for anticorrosion coating with benzotriazole.

Science.gov (United States)

Abdullayev, Elshad; Price, Ronald; Shchukin, Dmitry; Lvov, Yuri

2009-07-01

Halloysite clay nanotubes were investigated as a tubular container for the corrosion inhibitor benzotriazole. Halloysite is a naturally occurring cylindrical clay mineral with an internal diameter in the nanometer range and a length up to several micrometers, yielding a high-aspect-ratio hollow tube structure. Halloysite may be used as an additive in paints to produce a functional composite coating material. A maximum benzotriazole loading of 5% by weight was achieved for clay tubes of 50 nm external diameters and lumen of 15 nm. Variable release rates of the corrosion inhibitor were possible in a range between 5 and 100 h, as was demonstrated by formation of stoppers at tube openings. The anticorrosive performance of the sol-gel coating and paint loaded with 2-5% of halloysite-entrapped benzotriazole was tested on copper and on 2024-aluminum alloy by direct exposure of the metal plates to corrosive media. Kinetics of the corrosion spot formation at the coating defects was analyzed by the scanning vibrating electrode technique, and an essential damping of corrosion development was demonstrated for halloysite-loaded samples.

Estimation of tribological anticorrosion properties of impregnated nitriding layers

International Nuclear Information System (INIS)

Iwanow, J.; Senatorski, J.; Tacikowski, J.

1999-01-01

In this paper is described aim, experimental and test result of tribological anticorrosion properties of thin nitriding layer (12.5 μm) obtained on 45 steel grade in controlled gas-nitriding process (570 o C, 4 h) impregnated with oil-based formulations, containing corrosion inhibitor BS-43, modified with tribological additives based on ashen organometallic compounds as well as ash-free organic compounds. It was stated, that tribological additives does not influence, in fact, on behaviour of corrosion resistance of nitriding layers impregnated with oil-base formulations mainly connected with inhibitor BS-43. Synergy of tribological additive and corrosion inhibitor is however more visible in modelling of wear resistance of nitriding layer. The influence nature of tribological additives in combination with corrosion inhibitor BS-43 is dependent on their kind and as result improves or worsens the wear resistance by friction. Hence in choice of impregnated formulation, which is enable to accomplish of tribological anticorrosion requirements, determined, above all, tribological additive. (author)

The capability of graphene on improving the electrical conductivity and anti-corrosion properties of Polyurethane coatings

Science.gov (United States)

Tong, Yao; Bohm, Siva; Song, Mo

2017-12-01

Graphite and graphene particles were used to reinforce the electrical conductivity and anti-corrosion properties of polyurethane (PU) coatings. The effect of graphite and graphene were compared. Hybrid filler using carbon nanotube was adopted as well and the performance in electrical conductivity was much superior to single filler system. At the same filler loading, the electrical conductivity of hybrid filler system was significantly higher than single filler system (0.77 S/m at 5 wt% while single filler system was not conductive). The conductive mechanism was revealed. In terms of anti-corrosion properties, the coatings with low filler loading had better anti-corrosion properties. The resistance values obtained from EIS (Electrochemical Impedance Spectroscopy) and four point probe method were compared and discussed.

Evaluation of pawpaw leaves extract as anti-corrosion agent for ...

African Journals Online (AJOL)

Pawpaw leaves extract was examined as anti-corrosion agent for aluminium in hydrochloric acid medium. The extract and corrosion product were analyzed using Fourier transform infrared spectrophotometer (FTIR). Thermometric, gravimetric, potentiodynamic polarization and scanning electron microscopic methods were ...

Self-Healing anticorrosive coatings

DEFF Research Database (Denmark)

Nesterova, Tatyana

%. The number is lower than anticipated and needs to be confirmed. Finally, a 3-D model, based on Monte-Carlo simulations, has been developed for prediction of healing efficiency of a microcapsule-based anticorrosive coating. Two kinds of cracks were considered: cracks accommodated within the bulk coating...... associated with development and testing of this type of coating. A laboratory investigation, to identify the most suitable method for production of mechanically stable (filled with industrially relevant core materials) and forming a free-flowing powder upon drying microcapsules, has been performed. Four...... reduces the intensity of crack formation (both in number and length) compared to filler-containing coatings and prevents the coating from flaking upon damage. Based on specular gloss measurements, a preliminary critical pigment (microcapsule) concentration (CPVC) value was estimated to about 30 vol...

Effects of Polluted Water on the Metallic Water Pipelines

OpenAIRE

Abdul-Khaliq M. Hussain; Bashir A. Tantosh; El-Sadeg A. Abdalla

2010-01-01

Corrosion of metallic water pipelines buried below ground surface is a function of the nature of the surrounding soil and groundwater. This gives the importance of knowing the physical and chemical characteristics of the pipe-s surrounding environment. The corrosion of externally – unprotected metallic water pipelines, specially ductile iron pipes, in localities with aggressive soil conditions is becoming a significant problem. Anticorrosive protection for metallic water ...

Anticorrosion potential of hydralazine for corrosion of mild steel in ...

African Journals Online (AJOL)

Anticorrosion potential of mild steel by Hydralazine as corrosion inhibitor for mild steel in 1M hydrochloric acid was investigated by chemical and electrochemical measurements at 303-333 K temperature. The maximum inhibition efficiency of inhibitor by Weight loss method is around 90%, Tafel polarization method is ...

Graphite intercalated polyaniline composite with superior anticorrosive and hydrophobic properties, as protective coating material on steel surfaces

Energy Technology Data Exchange (ETDEWEB)

Rathnayake, R.M.N.M. [National Institute of Fundamental Studies, Kandy (Sri Lanka); Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Mantilaka, M.M.M.G.P.G. [Sri Lanka Institute of Nanotechnology, Nanotechnology and Science Park, Mahenwatte, Pitipana, Homagama (Sri Lanka); Hara, Masanori; Huang, Hsin-Hui [Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Wijayasinghe, H.W.M.A.C., E-mail: athula@ifs.ac.lk [National Institute of Fundamental Studies, Kandy (Sri Lanka); Yoshimura, Masamichi [Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Pitawala, H.M.T.G.A. [Department of Geology, University of Peradeniya, Peradeniya (Sri Lanka)

2017-07-15

Highlights: • In this paper, it has been utilized a novel method to prepare a new composite material of PANI/NPG graphite composite, using NPG vein graphite variety. • It is found that the composite works as an anti-corrosive coating on steel surfaces. Further, the prepared composite shows good hydrophobic ability, which is very useful in preventing corrosion on metal surfaces. • The prepared PANI/NPG composite material shows a significantly high corrosion resistance compared to alkyd resin/PANI coatings or alkyd resin coatings, on steel surfaces. - Abstract: Solid polymer composite systems are widely being used for potential technological applications in secondary energy sources and electrochromic devices. In this study, we synthesized and characterized a composite material composed of polyaniline (PANI) and natural needle platy (NPG) vein graphite. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), micro-Raman analysis, thermogravimetric and differential thermal analysis (TGA/DTA), transmission electron microscopy (TEM) were used to study the structural and electrochemical properties of the prepared PANI/NPG graphite composite. XPS, FTIR, and micro-Raman analysis confirmed the existence of relevant functional groups and bonding in the prepared PANI/NPG composite material. The composite shows a very low corrosion rate, approximately 29 μm per year, and high hydrophobicity on steel surfaces, which helps to prevent the corrosion due to O{sub 2} penetration towards the metal surface. It indicates that the composite can be used as a high potential surface coating material to anticorrosion. The specific capacitance of PANI/NPG composite is 833.3 F g{sup −1}, which is higher than that of PANI. This synergistic electrical performance result proves the prepared PANI/NPG graphite composite as a suitable protective coating material for steel

Anticorrosive coatings for storage tanks; Revestimentos anticorrosivos para tanques de armazenamento de petroquimicos

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Jeferson de [Coordenacao dos Programas de Pos-graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil). Lab. de Ensaios Nao Destrutivos, Corrosao e Soldagem; Silva, Cosmelina G. da; Mattos, Oscar R. [Coordenacao dos Programas de Pos-graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais; Margarit-Mattos, Isabel C.P. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Inorganicos; Solymossy, Victor; Quintela, Joaquim P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2008-07-01

The anticorrosive performance of commercial coatings that can be employed inside petrochemical storing reservoirs was evaluated. The aim is to select products able to extend the time between maintenance. Some of the products tested are composites and formulas with novolac resins. The tests were: cathodic delamination and total immersion in distilled water at 40 deg C, formation water at 80 deg C, NaOH 20%, H{sub 2}SO{sub 4} 20%, MIBK, ethanol and naphtha. The performance evaluation took into account the presence of corrosion, blistering, adhesion loss and electrochemical properties. Based on the results, considerations are made about the adequacy of tests and procedures for the new generations of organic anticorrosive coatings. (author)

Technology of Anticorrosive Protection of Steel Constructions by Coatings Based on Rapid-Hardening Bitumen-Latex Emulsion

Directory of Open Access Journals (Sweden)

Nykyforchyn, H.M.

2016-01-01

Full Text Available The recipes of rapid-hardening bitumen-latex emulsions and coatings on its base are created, in-laboratory tests of their physical, chemical and anticorrosive properties are carried out. The technology of anticorrosive protection and the installation technical documentation for making of aqueous bitumen-latex emulsion is developed, installation is mounted and a pilot lot of rapid-hardening emulsion is produced. Experimental-industrial approbation of the technology of coating formation on pipes in oil and gas industry is carried out.

Effect of Zinc Phosphate on the Corrosion Behavior of Waterborne Acrylic Coating/Metal Interface.

Science.gov (United States)

Wan, Hongxia; Song, Dongdong; Li, Xiaogang; Zhang, Dawei; Gao, Jin; Du, Cuiwei

2017-06-14

Waterborne coating has recently been paid much attention. However, it cannot be used widely due to its performance limitations. Under the specified conditions of the selected resin, selecting the function pigment is key to improving the anticorrosive properties of the coating. Zinc phosphate is an environmentally protective and efficient anticorrosion pigment. In this work, zinc phosphate was used in modifying waterborne acrylic coatings. Moreover, the disbonding resistance of the coating was studied. Results showed that adding zinc phosphate can effectively inhibit the anode process of metal corrosion and enhance the wet adhesion of the coating, and consequently prevent the horizontal diffusion of the corrosive medium into the coating/metal interface and slow down the disbonding of the coating.

Cold laminar galvanizing: a new anti-corrosion concept

International Nuclear Information System (INIS)

Bagnulo, L.H.

1984-01-01

Cold laminar galvanizing, a recent anticorrosion technology, now combines the most positive characteristics of the hot galvanizing protective systems. This patented technology has a zinc laminated foil (obtained by processing 99.9% pure zinc ingots) that is homogeneous and isotropic, with a standard thickness of 80-100μm. This foil is backed with an electro-conductive, selfadhesive glue prepared under an original formula. The zinc laminated foil offers excellent anchorage and elevated resistance to the main atmospheric agents

Nanoscale Characterization of Glass Flake Filled Vinyl Ester Anti-Corrosion Coatings

Directory of Open Access Journals (Sweden)

Salim Barbhuiya

2017-08-01

Full Text Available Vinyl ester is a thermoset matrix resin that is widely used in the coating industry. The presence of glass flakes further enhances the anti-corrosion performance of this coating. This paper reports the nanoscaled characterization of glass flake filled vinyl ester anti-corrosion coatings on mild steel. Bond strength properties of one uncoated and four coated samples with different thicknesses (300, 600, 900 and 1200 μm were studied using nanoscratch technique and ASTM Standard Test. It was found that the bond strength of coating with thickness 900 μm was the highest. The frequency distributions of elastic modulus on coating with 900 μm thickness determined using nanoindentation indicated that only 20–25% of the coating is composed of glass flakes and the balance is vinyl ester matrix. The critical depth at which the material is subject to failure due to external load and abrasion, was found to be around 100 nm.

Anticorrosion Coating using Olea sp. Leaves Extract

Science.gov (United States)

Ikhmal, W. M. K. W. M.; Yasmin, M. Y. N.; Fazira, M. F. M.; Rafizah, W. A. W.; Nik, W. B. Wan; Sabri, M. G. M.

2018-04-01

Olive leaves extract (OLE) was evaluated as green corrosion inhibitor for stainless steel grade 316L (SS316L) in several media using scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The Fourier Transform Infrared (FTIR) spectroscopy results reveals several active compound indicated by O-H stretch, C=O stretch, C-OH stretch and C-N stretch which can be attributed to oleuropein and hydroxtyrosol acting as the main inhibiting sources for corrosion. The results obtained also show the inhibition efficiency of OLE increase with the increase of OLE concentration. Through its inhibitive action elucidate from the electrochemical analysis, the extract was found to act as a mixed type inhibitor. Micrographs by SEM showed that the surface of steel which has been coated with 0% and 20% of OLE coating extract possess a lot of pin holes or pores while the steel with 10% of OLE coating extract shows the surface has multiple cracks. This study clearly shows the efficiency of OLE as anticorrosion coating for control of stainless steel in marine application.

Preparation of Phosphonic Acid Functionalized Graphene Oxide-modified Aluminum Powder with Enhanced Anticorrosive Properties

Science.gov (United States)

He, Lihua; Zhao, Yan; Xing, Liying; Liu, Pinggui; Wang, Zhiyong; Zhang, Youwei; Liu, Xiaofang

2017-07-01

To improve the anticorrosive performance of aluminum powder, a common functional filler in polymer coatings, we report a novel method to prepare graphene oxide modified aluminum powder (GO-Al) using 3-aminoproplyphosphoic acid as "link" agent. The GO nanosheets were firstly functionalized with 3-aminoproplyphosphoic acid (APSA) by the reaction of amine groups of APSA and the epoxy groups of GO. Subsequently, a layer of GO nanosheets uniformly and tightly covered the surface of flaky aluminum particle though the strong linking strength between -PO(OH)2 functional groups of the modified GO and aluminum. The hydrogen evolution experiment suggests that the GO attached on the aluminum powder could effectively improve the anticorrosive performance of the pigments.

Anti-corrosion mechanism of epoxy-resin and different content Fe2O3 coatings on magnesium alloy

Science.gov (United States)

Jin, Tao; Kong, Fan-mei; Bai, Rui-qin; Zhang, Ru-liang

2016-12-01

In this study, anti-corrosion coatings were prepared and coated successfully on magnesium alloy substrates by mixing nanopowders, solvent, curing agent with epoxy resin. The effect of the amount of iron trioxide (Fe2O3) on the adhesion strength and corrosion resistance on magnesium alloy was investigated with standard protocols, and electrochemical measurements were also made in 3.5 wt.% NaCl solutions. The surface morphology and corrosion mechanism after corrosion tests was characterized using FESEM analysis. Nanoparticles in matrix acted as filler, and interstitial cross-linked spaces and other coating artifacts regions (micro cracks and voids) would all affect the anti-corrosion properties of coating. The results showed the proper powder content not only provided adhesion strength to these coatings but also improved obviously their anticorrosion. Hydrogen bound to the amine nitrogen (1N) could take part in the curing process rather than hydrogen of the amide site due to the smaller Δ G and the more stable configuration.

Anti-corrosion performance of oxidized and oxygen plasma-implanted NiTi alloys

International Nuclear Information System (INIS)

Poon, Ray W.Y.; Ho, Joan P.Y.; Liu, Xuanyong; Chung, C.Y.; Chu, Paul K.; Yeung, Kelvin W.K.; Lu, William W.; Cheung, Kenneth M.C.

2005-01-01

Nickel-titanium shape memory alloys are useful orthopedic biomaterials on account of its super-elastic and shape memory properties. However, the problem associated with out-diffusion of harmful nickel ions in prolonged use inside the human body raises a critical safety concern. Titanium oxide films are deemed to be chemically inert and biocompatible and hence suitable to be the barrier layers to impede the leaching of Ni from the NiTi substrate to biological tissues and fluids. In the work reported in this paper, we compare the anti-corrosion efficacy of oxide films produced by atmospheric-pressure oxidation and oxygen plasma ion implantation. Our results show that the oxidized samples do not possess improved corrosion resistance and may even fare worse than the untreated samples. On the other hand, the plasma-implanted surfaces exhibit much improved corrosion resistance. Our work also shows that post-implantation annealing can further promote the anti-corrosion capability of the samples

Fabrication and Assessment of Crumb-Rubber-Modified Coatings with Anticorrosive Properties

Directory of Open Access Journals (Sweden)

Nasser Al-Aqeeli

2015-01-01

Full Text Available Scrap tires continue to be a major source of waste due to the lack of valuable and effective disposal routes. A viable solution to this problem is to recycle crumb rubber (CR—a granulated material derived from scrap tires—and use it to develop other valuable products. Herein we report the fabrication and characterization of CR-modified coatings with anticorrosive properties on metal substrates. By varying the particle size and concentration of CR, we have determined the coating composition that offers the highest level of erosion protection. Images from a scanning electron microscope (SEM reveal that CR is homogenously dispersed in the coating, especially when fine particles are used. As the concentration of CR increases, the hardness of the coating decreases as a result of the elastic properties of CR. More importantly, the erosion rate of the coating decreases due to increased ductility. Following Potentiodynamic tests, the utilization of these coatings proved to be beneficial as they showed good protection against aqueous corrosion when tested in 0.5 M NaCl solution. Our newly developed coatings offer an incentive to recycling CR and open up a safe and sustainable route to the disposal of scrap tires.

Fabrication and Assessment of Crumb-Rubber-Modified Coatings with Anticorrosive Properties.

Science.gov (United States)

Al-Aqeeli, Nasser

2015-01-06

Scrap tires continue to be a major source of waste due to the lack of valuable and effective disposal routes. A viable solution to this problem is to recycle crumb rubber (CR)-a granulated material derived from scrap tires-and use it to develop other valuable products. Herein we report the fabrication and characterization of CR-modified coatings with anticorrosive properties on metal substrates. By varying the particle size and concentration of CR, we have determined the coating composition that offers the highest level of erosion protection. Images from a scanning electron microscope (SEM) reveal that CR is homogenously dispersed in the coating, especially when fine particles are used. As the concentration of CR increases, the hardness of the coating decreases as a result of the elastic properties of CR. More importantly, the erosion rate of the coating decreases due to increased ductility. Following Potentiodynamic tests, the utilization of these coatings proved to be beneficial as they showed good protection against aqueous corrosion when tested in 0.5 M NaCl solution. Our newly developed coatings offer an incentive to recycling CR and open up a safe and sustainable route to the disposal of scrap tires.

Anticorrosion protection of uranium

Energy Technology Data Exchange (ETDEWEB)

Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav [Russian Federal Nuclear Center-VNIIEF, 37, Mira Ave., RU-607190 Sarov (Nizhnii Gorod), 010450 (Russian Federation)

2004-07-01

Uranium in atmospheric conditions is non-stable. Sloughing products are being generated on its surface during storage or use. These corrosion products make many difficulties because of necessity to provide personnel safety. Besides, uranium corrosion may cause damage in parts. The first works devoted to uranium corrosion were performed in the framework of the USA Manhattan Project in the early forties of last century. Various methods of uranium protection were investigated, among them the galvanic one was the most studied. Later on the galvanic technology was patented. The works on this problem remains urgent up to the present time. In Russia, many methods of uranium corrosion protection, mainly against atmospheric corrosion, were tried on. In particular, such methods as diffusion zinc and paint coating were investigated. In the first case, a complex intermetallic U-Zn compound was formed but its protection was not reliable enough, this protection system was inconvenient and uncertain and that is why an additional paint coating was necessary. In the case of paint coatings another problem appeared. It was necessary to find such a coating where gas-permeability would prevail over water-permeability. Otherwise significant uranium corrosion occurs. This circumstance together with low mechanical resistance of paint coatings does not allow to use paint coating for long-term protection of uranium. Currently, there are following methods of uranium protection: ion-plasma, galvanic and thermo-vacuum annealing. These are described in this paper. In the end the issue of corrosion protection in reactor core zones is addressed. Here the greatest difficulties are caused when enriched uranium heated up to 500 deg. C needs anticorrosion protection. In this case various metal coatings are not reliable because of brittle inter-metallide formation. The reliable protection may be provided only up to the temperature plus 400 - 500 deg. C with the help of galvanic copper coating since

Anticorrosion protection of uranium

International Nuclear Information System (INIS)

Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav

2004-01-01

Uranium in atmospheric conditions is non-stable. Sloughing products are being generated on its surface during storage or use. These corrosion products make many difficulties because of necessity to provide personnel safety. Besides, uranium corrosion may cause damage in parts. The first works devoted to uranium corrosion were performed in the framework of the USA Manhattan Project in the early forties of last century. Various methods of uranium protection were investigated, among them the galvanic one was the most studied. Later on the galvanic technology was patented. The works on this problem remains urgent up to the present time. In Russia, many methods of uranium corrosion protection, mainly against atmospheric corrosion, were tried on. In particular, such methods as diffusion zinc and paint coating were investigated. In the first case, a complex intermetallic U-Zn compound was formed but its protection was not reliable enough, this protection system was inconvenient and uncertain and that is why an additional paint coating was necessary. In the case of paint coatings another problem appeared. It was necessary to find such a coating where gas-permeability would prevail over water-permeability. Otherwise significant uranium corrosion occurs. This circumstance together with low mechanical resistance of paint coatings does not allow to use paint coating for long-term protection of uranium. Currently, there are following methods of uranium protection: ion-plasma, galvanic and thermo-vacuum annealing. These are described in this paper. In the end the issue of corrosion protection in reactor core zones is addressed. Here the greatest difficulties are caused when enriched uranium heated up to 500 deg. C needs anticorrosion protection. In this case various metal coatings are not reliable because of brittle inter-metallide formation. The reliable protection may be provided only up to the temperature plus 400 - 500 deg. C with the help of galvanic copper coating since

Self-healing Anticorrosion Coatings for Gas Pipelines and Storage Tanks

Energy Technology Data Exchange (ETDEWEB)

Luckachan, G. E.; Mittal, V. [The Petroleum Institute, Abudhabi (United Arab Emirates)

2016-10-15

In the present study, chitosan based self-healing anticorrosion coatings were prepared by layer by layer (lbl) addition of chitosan (Ch) and polyvinyl butyral (PVB) on mild carbon steel substrate. Chitosan coatings exhibited enhanced coating stability and corrosion resistance in aggressive environments by the application of a PVB top layer. Chitosan layer in the lbl coatings have been modified by using glutaraldehyde (Glu) and silica (SiO{sub 2}). Performance of different coatings was tested using electrochemical impedance spectroscopy and immersion test. The best anticorrosion performance was observed in case of 10 % Ch{sub S}iO{sub 2P}VB coatings, which withstand immersion test over 25 days in 0.5 M salt solution without visible corrosion. 10 % Ch{sub S}iO{sub 2} coatings without the PVB top layer didn't last more than 3days. Application of PVB top layer sealed the defects in the chitosan pre-layer and improved its hydrophobic nature as well. Raman spectra and SEM of steel surfaces after corrosion study and removal of PVB{sub C}h/Glu{sub P}VB coatings showed a passive layer of iron oxide, attributing to the self-healing nature of these coatings. Conducting particle like graphene reinforcement of chitosan in the lbl coatings enhanced corrosion resistance of chitosan coatings.

Al-based anti-corrosion and T-permeation barrier development for future DEMO blankets

International Nuclear Information System (INIS)

Krauss, W.; Konys, J.; Holstein, N.; Zimmermann, H.

2011-01-01

In the Helium-Cooled-Liquid-Lead (HCLL) design of Test-Blanket-Modules (TBM's) for a future fusion power plant Pb-15.7Li is used as liquid breeder which is in direct contact with the structure material, e.g. EUROFER steel. Compatibility testing showed that high corrosion attack appears and that the dissolved steel components form precipitates with a high risk of system blockages. A reliable operation needs coatings as corrosion barriers. The earlier developed Hot-Dip Aluminisation (HDA) process has shown that Al-based scales can act as anti-corrosion as well as T-permeation barriers. Meanwhile two advanced electro-chemically based processes for deposition of Al-scales were successfully developed. The first (ECA = Electro-Chemical Al-deposition) is working with an organic electrolyte and the second one (ECX = Electro-Chemical-X-metal-deposition) is based on ionic liquids. Coatings in the μm-range were deposited homogeneously with exact controllable thicknesses. Metallurgical investigations showed the successful generation of protective scales and compatibility testing demonstrated the barrier function.

Al-based anti-corrosion and T-permeation barrier development for future DEMO blankets

Energy Technology Data Exchange (ETDEWEB)

Krauss, W., E-mail: wolfgang.krauss@kit.edu [Karlsruhe Institute of Technology, Hermann von Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Konys, J.; Holstein, N.; Zimmermann, H. [Karlsruhe Institute of Technology, Hermann von Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2011-10-01

In the Helium-Cooled-Liquid-Lead (HCLL) design of Test-Blanket-Modules (TBM's) for a future fusion power plant Pb-15.7Li is used as liquid breeder which is in direct contact with the structure material, e.g. EUROFER steel. Compatibility testing showed that high corrosion attack appears and that the dissolved steel components form precipitates with a high risk of system blockages. A reliable operation needs coatings as corrosion barriers. The earlier developed Hot-Dip Aluminisation (HDA) process has shown that Al-based scales can act as anti-corrosion as well as T-permeation barriers. Meanwhile two advanced electro-chemically based processes for deposition of Al-scales were successfully developed. The first (ECA = Electro-Chemical Al-deposition) is working with an organic electrolyte and the second one (ECX = Electro-Chemical-X-metal-deposition) is based on ionic liquids. Coatings in the {mu}m-range were deposited homogeneously with exact controllable thicknesses. Metallurgical investigations showed the successful generation of protective scales and compatibility testing demonstrated the barrier function.

An intelligent anticorrosion coating based on pH-responsive supramolecular nanocontainers

International Nuclear Information System (INIS)

Chen Tao; Fu Jiajun

2012-01-01

The hollow mesoporous silica nanoparticles (HMSNs), which have been used as the nanocontainers for the corrosion inhibitor, benzotriazole, were fabricated using the hard-template method. Alkaline-responsive HMSNs based on cucurbit[6]uril (CB[6])/bisammonium supramolecular complex and acid-responsive HMSNs based on α-cyclodextrin (α-CD)/aniline supramolecular complex, which operate in water, have been achieved and characterized by solid-state NMR, thermogravimetry analysis, scanning electron microscopy, transmission electron microscopy and N 2 adsorption-desorption analysis. The two elaborately designed nanocontainers show the pH-controlled encapsulation/release behaviors for benzotriazole molecules. Equal amounts of the alkaline- and acid-responsive nanocontainers were uniformly distributed in the hybrid zirconia-silica sol–gel coating and thus formed the intelligent anticorrosion coating. The self-healing property of AA2024 alloy coated with the intelligent anticorrosion coating is evaluated by electrochemical impedance spectroscopy (EIS). The sol–gel coating doped with the pH-responsive nanocontainers clearly demonstrates long-term corrosion protection performances when compared to the undoped sol–gel coating, which is attributed to the release of corrosion inhibitor from the nanocontainers after feeling the changes of environmental pH values near the corroded areas. (paper)

Layer-by-Layer Assembly of a Self-Healing Anticorrosion Coating on Magnesium Alloys.

Science.gov (United States)

Fan, Fan; Zhou, Chunyu; Wang, Xu; Szpunar, Jerzy

2015-12-16

Fabrication of self-healing anticorrosion coatings has attracted attention as it has the ability to extend the service life and prevent the substrate from corrosive attack. However, a coating system with a rapid self-healing ability and an improved corrosion resistance is rarely reported. In this work, we developed a self-healing anticorrosion coating on a magnesium alloy (AZ31). The coating comprises a cerium-based conversion layer, a graphene oxide layer, and a branched poly(ethylene imine) (PEI)/poly(acrylic acid) (PAA) multilayer. We incorporated the graphene oxide as corrosion inhibitors and used the PEI/PAA multilayers to provide the self-healing ability to the coating systems. X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the composition of the multilayers, and scanning electron microscopy (SEM) was used to analyze the surface morphology. The electrochemical impedance spectroscopy (EIS) results illustrate the improved corrosion resistance of the coating. The proposed coating also has a rapid self-healing ability in the presence of water.

Development of an environmentally benign anticorrosion coating for aluminum alloy using green pigments and organofunctional silanes

Science.gov (United States)

Yin, Zhangzhang

Aerospace aluminum alloys such as Al alloy 2024-T3 and 7075-T6 are subject to localized corrosion due the existence of intermetallics containing Cu, Mg or Zn. Current protection measurement employs substantial use of chromate and high VOC organics, both of which are identified as environment and health hazards. The approach of this study is to utilize a combination of organofunctional silanes and a compatible inhibitor integrated into high-performance waterborne resins. First, an extensive pigment screening has been done to find replacements for chromates using the testing methodology for fast corrosion inhibition evaluation and pigment. Zinc phosphate and calcium zinc phosphomolybdate were found to have the best overall performance on Al alloys. Some new corrosion inhibitors were synthesized by chemical methods or modified by plasma polymerization for use in the coatings. Low-VOC, chromate-free primers (superprimer) were developed using these pigments with silane and acrylic-epoxy resins. The developed superprimer demonstrated good corrosion inhibition on aluminum substrates. The functions of inhibitor and silane in the coating were investigated. Both silane and inhibitor are critical for the performance of the superprimer. Silane was found to improve the adhesion of the coating to the substrate and also facilitate corrosion prevention. Addition of zinc phosphate to the coating improved the resistance of a scratched area against corrosion. The microstructure of the acrylic-epoxy superprimer coating was studied. SEM/EDAX revealed that the superprimer has a self-assembled stratified double-layer structure which accounts for the strong anti-corrosion performance of the zinc phosphate pigment. Zinc phosphate leaches out from the coating to actively protect the scratched area. The leaching of pigment was confirmed in the ICP-MS analysis and the leaching rate was measured. Coating-metal interface and the scribe of coated panels subjected to corrosion test was studied

Superhydrophobic Copper Surfaces with Anticorrosion Properties Fabricated by Solventless CVD Methods.

Science.gov (United States)

Vilaró, Ignasi; Yagüe, Jose L; Borrós, Salvador

2017-01-11

Due to continuous miniaturization and increasing number of electrical components in electronics, copper interconnections have become critical for the design of 3D integrated circuits. However, corrosion attack on the copper metal can affect the electronic performance of the material. Superhydrophobic coatings are a commonly used strategy to prevent this undesired effect. In this work, a solventless two-steps process was developed to fabricate superhydrophobic copper surfaces using chemical vapor deposition (CVD) methods. The superhydrophobic state was achieved through the design of a hierarchical structure, combining micro-/nanoscale domains. In the first step, O 2 - and Ar-plasma etchings were performed on the copper substrate to generate microroughness. Afterward, a conformal copolymer, 1H,1H,2H,2H-perfluorodecyl acrylate-ethylene glycol diacrylate [p(PFDA-co-EGDA)], was deposited on top of the metal via initiated CVD (iCVD) to lower the surface energy of the surface. The copolymer topography exhibited a very characteristic and unique nanoworm-like structure. The combination of the nanofeatures of the polymer with the microroughness of the copper led to achievement of the superhydrophobic state. AFM, SEM, and XPS were used to characterize the evolution in topography and chemical composition during the CVD processes. The modified copper showed water contact angles as high as 163° and hysteresis as low as 1°. The coating withstood exposure to aggressive media for extended periods of time. Tafel analysis was used to compare the corrosion rates between bare and modified copper. Results indicated that iCVD-coated copper corrodes 3 orders of magnitude slower than untreated copper. The surface modification process yielded repeatable and robust superhydrophobic coatings with remarkable anticorrosion properties.

Large-scale fabrication of superhydrophobic polyurethane/nano-Al2O3 coatings by suspension flame spraying for anti-corrosion applications

Science.gov (United States)

Chen, Xiuyong; Yuan, Jianhui; Huang, Jing; Ren, Kun; Liu, Yi; Lu, Shaoyang; Li, Hua

2014-08-01

This study aims to further enhance the anti-corrosion performances of Al coatings by constructing superhydrophobic surfaces. The Al coatings were initially arc-sprayed onto steel substrates, followed by deposition of polyurethane (PU)/nano-Al2O3 composites by a suspension flame spraying process. Large-scale corrosion-resistant superhydrophobic PU/nano-Al2O3-Al coatings were successfully fabricated. The coatings showed tunable superhydrophilicity/superhydrophobicity as achieved by changing the concentration of PU in the starting suspension. The layer containing 2.0 wt.%PU displayed excellent hydrophobicity with the contact angle of ∼151° and the sliding angle of ∼6.5° for water droplets. The constructed superhydrophobic coatings showed markedly improved anti-corrosion performances as assessed by electrochemical corrosion testing carried out in 3.5 wt.% NaCl solution. The PU/nano-Al2O3-Al coatings with superhydrophobicity and competitive anti-corrosion performances could be potentially used as protective layers for marine infrastructures. This study presents a promising approach for fabricatiing superhydrophobic coatings for corrosion-resistant applications.

Corrosion and Protection of Metal in the Seawater Desalination

Science.gov (United States)

Hou, Xiangyu; Gao, Lili; Cui, Zhendong; Yin, Jianhua

2018-01-01

Seawater desalination develops rapid for it can solve water scarcity efficiently. However, corrosion problem in the seawater desalination system is more serious than that in normal water. So, it is important to pay attention to the corrosion and protection of metal in seawater desalination. The corrosion characteristics and corrosion types of metal in the seawater desalination system are introduced in this paper; In addition, corrosion protect methods and main influencing factors are stated, the latest new technologies about anti-corrosion with quantum energy assisted and magnetic inhibitor are presented.

Anticorrosive behaviour of Cr(VI)-free surface pretreatments applied on magnesium alloys

OpenAIRE

Simancas Peco, Joaquín; Fuente, Daniel de la; Chico, Belén; Madueño, L.; Camón, F.; Blanco, M. C.; Morcillo, Manuel

2013-01-01

Among the anticorrosive protection technologies for magnesium alloys, the development of paint systems is a pressing need especially for the automotive and aeronautical industries. Conventional technologies are based on the use of Cr(VI) based compounds, both in pretreatments and primers, but for health and environmental reasons these technologies are being abandoned. An added problem in the painting of magnesium alloys is the lack of adhesion and the high reactivity of magnesium substrates, ...

Comparative study on Ti/Zr/V and chromate conversion treated aluminum alloys: Anti-corrosion performance and epoxy coating adhesion properties

Energy Technology Data Exchange (ETDEWEB)

Zhu, Wen; Li, Wenfang, E-mail: mewfli@163.com; Mu, Songlin; Fu, Nianqing; Liao, Zhongmiao

2017-05-31

Highlights: • The surface roughness and surface free energy of the AA6063 are significantly increased after TZVCC treatment. • The anti-corrosion performance of the AA6063 is effectively enhanced after TZVCC treatment. • Both the corrosion resistance and wet adhesion properties of the epoxy coating on the AA6063 are noticeably improved after TZVCC treatment. - Abstract: In this study, a Ti/Zr/V conversion coating (TZVCC) was deposited on the surface of aluminum alloy 6063 (AA6063) as an alternative of the chromate conversion coating (CCC). Both the TZVCC treated AA6063 (TZVCC/AA6063) and CCC treated AA6063 (CCC/AA6063) were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and contact angle measuring device. The anti-corrosion performance of the TZVCC/AA6063 and CCC/AA6063 was evaluated by electrochemical measurements and neutral salt spray tests. It showed that both the surface roughness and surface free energy of the AA6063 were significantly increased after TZVCC treatment. The anti-corrosion performance of TZVCC/AA6063 was superior to that of CCC/AA6063. In addition, the effects of the TZVCC and CCC on the adhesion properties and anti-corrosion performance of epoxy coating applied on samples were examined by pull-off tests and electrochemical impedance spectroscopy (EIS). The dry, wet and recovery adhesive strengths of the epoxy coating on TZVCC treated samples (epoxy coated TZVCC/AA6063) were very close to those of epoxy coating on CCC treated ones (epoxy coated CCC/AA6063). The epoxy coated TZVCC/AA6063 showed better corrosion resistance than the epoxy coated CCC/AA6063 and epoxy coated AA6063.

The anti-corrosion behavior under multi-factor impingement of Hastelloy C22 coating prepared by multilayer laser cladding

Science.gov (United States)

Chen, Lin; Bai, Shu-Lin

2018-04-01

Hastelloy C22 coating was prepared on substrate of Q235 steel by high power multilayer laser cladding. The microstructure, hardness and anti-corrosion properties of coating were investigated. The corrosion tests in 3.5% NaCl solution were carried out with variation of impingement angle and velocity, and vibration frequency of sample. The microstructure of coating changes from equiaxed grain at the top surface to dendrites oriented at an angle of 60° to the substrate inside the coating. The corrosion rate of coating increases with the increase of impingement angle and velocity, and vibrant frequency of sample. Corrosion mechanisms relate to repassivation and depassivation of coating according to electrochemical measurements. Above results show that multilayer laser cladding can endow Hastelloy C22 coating with fine microstructures, high hardness and good anti-corrosion performances.

Dual functions of imidazole-based polymeric ionic liquid (PIL) on the anticorrosive performance of graphene-based waterborne epoxy coatings

Science.gov (United States)

Liu, Chengbao; Du, Peng; Nan, Feng; Zhao, Haichao; Wang, Liping

2018-06-01

Dispersion of graphene nanosheets in a water and polymer matrix has been rarely achieved due to graphene’s hydrophobicity, which thus impedes its potential anticorrosive application. In this study, stable graphene aqueous dispersion was obtained by using imidazole-based polymeric ionic liquid (PIL) as the dispersant with ultrasonic vibration. Stacked graphene sheets were exfoliated to a few layers via cation-π interaction between PIL and graphene nanosheets. Electrochemical impedance measurements were taken to investigate the anticorrosion performance of epoxy coatings with or without polymeric ionic liquid–graphene (PIL–G) hybrids. Results indicated that the PIL–G hybrid significantly enhanced the long-term protective performance of epoxy coatings, which was attributed to the synergistic effects of the corrosion-inhibitive PIL and impermeable graphene nanosheets.

A new smart additive of reinforced concrete based on modified hydrotalcites: Preparation, characterization and anticorrosion applications

NARCIS (Netherlands)

Yang, Z.; Fischer, H.; Polder, R.

2012-01-01

A carbonate form of Mg-Al-hydrotalcite and its p-aminobenzoate (pAB) modified derivative (i.e.,Mg(2)Al-pAB) were synthesized and characterized by means of XRD and FT-IR. The anticorrosion behavior was evaluated based on open circuit potential (OCP) of carbon steel in simulated concrete pore solution

A Comparative Study on Graphene Oxide and Carbon Nanotube Reinforcement of PMMA-Siloxane-Silica Anticorrosive Coatings.

Science.gov (United States)

Harb, Samarah V; Pulcinelli, Sandra H; Santilli, Celso V; Knowles, Kevin M; Hammer, Peter

2016-06-29

Carbon nanotubes (CNTs) and graphene oxide (GO) have been used to reinforce PMMA-siloxane-silica nanocomposites considered to be promising candidates for environmentally compliant anticorrosive coatings. The organic-inorganic hybrids were prepared by benzoyl peroxide (BPO)-induced polymerization of methyl methacrylate (MMA) covalently bonded through 3-(trimethoxysilyl)propyl methacrylate (MPTS) to silica domains formed by hydrolytic condensation of tetraethoxysilane (TEOS). Single-walled carbon nanotubes and graphene oxide nanosheets were dispersed by surfactant addition and in a water/ethanol solution, respectively. These were added to PMMA-siloxane-silica hybrids at a carbon (CNT or GO) to silicon (TEOS and MPTS) molar ratio of 0.05% in two different matrices, both prepared at BPO/MMA molar ratios of 0.01 and 0.05. Atomic force microscopy and scanning electron microscopy showed very smooth, homogeneous, and defect-free surfaces of approximately 3-7 μm thick coatings deposited onto A1020 carbon steel by dip coating. Mechanical testing and thermogravimetric analysis confirmed that both additives CNT and GO improved the scratch resistance, adhesion, wear resistance, and thermal stability of PMMA-siloxane-silica coatings. Results of electrochemical impedance spectroscopy in 3.5% NaCl solution, discussed in terms of equivalent circuits, showed that the reinforced hybrid coatings act as a very efficient anticorrosive barrier with an impedance modulus up to 1 GΩ cm(2), approximately 5 orders of magnitude higher than that of bare carbon steel. In the case of GO addition, the high corrosion resistance was maintained for more than 6 months in saline medium. These results suggest that both carbon nanostructures can be used as structural reinforcement agents, improving the thermal and mechanical resistance of high performance anticorrosive PMMA-siloxane-silica coatings and thus extending their application range to abrasive environments.

Nanostructured superhydrophobic polysiloxane coating for high barrier and anticorrosion applications in marine environment.

Science.gov (United States)

Arukalam, Innocent O; Oguzie, Emeka E; Li, Ying

2018-02-15

The use of epoxy and polyurethane coatings as marine topcoats, have been influenced by their inherent high surface energy property which increases their affinity to water and microorganisms. Thus, their susceptibility to degradation is enhanced. Because of this defect, recently, nanostructured hydrophobic and superhydrophobic polysiloxane coatings are being preferred as topcoats. But the appropriate nanoparticle size and matrix:filler ratio which provide guide for the design of desired topcoats are scarcely available. In view of this, a series of hydrophobic and superhydrophobic coatings were prepared by sol-gel process based on perfluorodecyltrichlorosilane (FDTS), different nanoZnO particles and poly(dimethylsiloxane) (PDMS):nanoZnO ratios. The liquid repellency, surface morphology and roughness of the coatings were conducted by use of contact angle goniometer, field emission scanning electron microscopy and atomic force microscopy, respectively. Additionally, the electrochemical and salt spray corrosion tests were conducted. According to the results, modifications of the coatings showed that anticorrosion performance was considerably influenced by the surface properties which were dependent on nanoZnO size and PDMS:nanoZnO ratio. Remarkably, the optimum effect was observed on the superhydrophobic coating based on 30 nm ZnO and 1:1 ratio. This displayed highest anticorrosion performance, and is therefore recommended as a guide for the design of marine topcoats. Copyright © 2017 Elsevier Inc. All rights reserved.

Green options for anti-corrosion of high strength concrete incorporating ternary pozzolan materials

Directory of Open Access Journals (Sweden)

Chen Yuan-Yuan

2017-01-01

Full Text Available This paper applied the densified mixture design algorithm(DMDA method by incorporating ternary pozzolans (fly ash, slag and silica fume; mix I and mix II to design high strength concrete (HSC mixtures with w/cm ratios from 0.24 to 0.30. Concrete without pozzolans was used as a control group (mix III, w/c from 0.24 to 0.30, and silica fume (5% was added as a substitute for part of the cement and set as mix IV. Experiments performed compressive strength, four-point resistance meter to measure the conductivity, and rapid chloride ion penetrability tests (ASTM C1202 were assessed the anti-corrosion. The life cycle inventory of LEED suggested by the PCA indicated the green options for cementitious materials. Results showed that mix I and II indicated cement used, CO2 reduction, raw materials and energy consumption all decreased more 50% than mix III, and mix IV was 5% less. The compressive strength and anti-corrosion levels showed that mix I and II were better than mix III and IV, and with ternary pozzolans could enhance the long-term durability (92 days due to a resistivity greater 20 KΩ-cm and a charge passed lower than 2000 Coulombs. HSC with an appropriate design could reduce the carbon footprint and improve the durability.

Aminobenzoate modified MgAl hydrotalcites as a novel smart additive of reinforced concrete for anticorrosion applications

NARCIS (Netherlands)

Yang, Z.; Fischer, H.R.; Cerezo, J.; Mol, J.M.C.; Polder, R.B.

2013-01-01

A carbonate form of MgAl hydrotalcite, Mg(2)Al-CO3 and its p-aminobenzoate (pAB) modified derivative, Mg(2)Al-pAB, were synthesized and characterized by means of XRD, FT-IR and TG/DSC. The anticorrosion behavior of Mg(2)Al-pAB was evaluated based on open circuit potential (OCP) of carbon steel in

Self-healing anticorrosive organic coating based on an encapsulated water reactive silyl ester: synthesis and proof of concept

NARCIS (Netherlands)

García, S.J.; Fischer, H.R.; White, P.A.; Mardel, J.; González-García, Y.; Mol, J.M.C.; Hughes, A.E.

2011-01-01

In this paper a self-healing anticorrosive organic coating based on an encapsulated water reactive organic agent is presented. A reactive silyl ester is proposed as a new organic reactive healing agent and its synthesis, performance, incorporation into an organic coating and evaluation of

Phosphates based pigments for new anti-corrosion application: Synthesis and characterization

Science.gov (United States)

Tbib, B.; Eddya, M.; El-Hami, K.

2018-02-01

Our study focused on pyrophosphates SrZn1-xMxP2O7 using four series by substituting M with manganese (Mn), cobalt (Co), nickel (Ni), and copper (Cu). They were prepared by reaction in the solid state at 1000 °C for 24 hours and then characterized by X-ray diffraction, which showed that the obtained products are pure. The characterization by UV-visible spectroscopy was used to explain the color of the obtained materials and the optical properties showing the optical energy gap and disorder of these materials. Potential application could be done using the new anti-corrosion pigments based on phosphates.

Evaluation of Iron Nickel Oxide Nanopowder as Corrosion Inhibitor: Effect of Metallic Cations on Carbon Steel in Aqueous NaCl

Energy Technology Data Exchange (ETDEWEB)

Chaudhry, A. U.; Mishra, Brajendra [Colorado School of Mines, Denver (United States); Mittal, Vikas [The Petroleum Institute, Abu Dhabi (United Arab Emirates)

2016-01-15

The aim of this study was to evaluate the use of iron-nickel oxide (Fe{sub 2}O{sub 3}.NiO) nanopowder (FeNi) as an anti-corrosion pigment for a different application. The corrosion protection ability and the mechanism involved was determined using aqueous solution of FeNi prepared in a corrosive solution containing 3.5 wt.% NaCl. Anti-corrosion abilities of aqueous solution were determined using electrochemical impedance spectroscopy (EIS) on line pipe steel (API 5L X-80). The protection mechanism involved the adsorption of metallic cations on the steel surface forming a protective film. Analysis of EIS spectra revealed that corrosion inhibition occurred at low concentration, whereas higher concentration of aqueous solution produced induction behavior.

Influence of anti-corrosion additive on the performance, emission and engine component wear characteristics of an IDI diesel engine fueled with palm biodiesel

International Nuclear Information System (INIS)

Ashraful, A.M.; Masjuki, H.H.; Kalam, M.A.; Rashedul, H.K.; Sajjad, H.; Abedin, M.J.

2014-01-01

Highlights: • Maximum engine performance was obtained at 2000 rpm for all fuel blends. • IRGALUBE 349 additive is enhances diesel engine performance. • Reduction of CO and NOx considerably using anti-corrosion additive except HC. • Engine wear decreases with using blended fuels with anti-corrosion additive. - Abstract: This study evaluates the effect of anti-corrosion additives such as 8% and 16% (vol.%) palm olein oil (PO) with ordinary diesel (OD) fuel on engine operation, emission behavior, engine part wear, and lubrication characteristics. This experiment was conducted on 4-cylinder and 4-stroke IDI diesel engine at different engine speed ranging from 1200 to 2800 RPM with 30% throttle setting under full load condition. The properties of the palm olein oil blends meet the ASTM D6751 and EN 14214 standards. At 2000 rpm, the experimental results revealed that the POD8A (0.2% Additive + 8% PO + 92% OD) and POD16A (0.2% Additive + 16% PO + 84% OD) blended fuels produced 0.5% and 0.51% higher brake power as well as 1.45% and 1.25% higher torque than same blends without additive, respectively. In comparison with ODF, the brake specific fuel consumption (BSFC) was found 1.8% and 3.1% higher for POD8A and POD16A blends, respectively. Anti-corrosion additive is found more effectual in enhancing the engine performance as such additive helps in timely ignition for complete burn in the combustion chamber. The results from engine emission indicated that POD8A and POD16A blended fuel reduced CO emissions by 11% and 6.6% and NOx emission by 2.5% and 1.09%, respectively in compared with OD fuel. Although HC emissions for all blended fuel and OD fuel increased at higher engine speed, the average HC emissions of all blended fuel were not higher than OD fuel. The application of anti-corrosion additives in POD blends reduced ferrous (Fe) wear debris concentration (WBC) by 17.3%. The reductions in WBC were about 16.1%, 10.8%, and 19.3%, 17.6% for copper (Cu) and aluminum

Anticorrosive magnesium hydroxide coating on AZ31 magnesium alloy by hydrothermal method

International Nuclear Information System (INIS)

Zhu Yanying; Wu Guangming; Xing Guangjian; Li Donglin; Zhao Qing; Zhang Yunhong

2009-01-01

Magnesium alloys are potential biodegradable biomaterials in orthopedic surgery. However, the rapid degradation rate has limited their application in biomedical field. A great deal of studies have been done to improve the resistance of magnesium alloys. In this article, An anticorrosive magnesium hydroxide coating with a thickness of approximately 100μm was formed on an AZ31 magnesium alloy by hydrothermal method. The morphology of the coatings were observed by an optical microscope and SEM. And the samples were soaked in hank's solution (37 deg. C) to investigate the corrosion resistance. Magnesium alloy AZ31 with magnesium hydroxide coatings present superior corrosion resistance than untreated samples.

Anticorrosive Properties of Poly(o-phenylenediamine/ZnO Nanocomposites Coated Stainless Steel

Directory of Open Access Journals (Sweden)

Aisha Ganash

2014-01-01

Full Text Available Poly(o-phenylenediamine and poly(o-phenylenediamine/ZnO (PoPd/ZnO nanocomposites coating were prepared on type-304 austenitic stainless steel (SS using H2SO4 acid as electrolyte by potentiostatic methods. Fourier transforms infrared spectroscopy and scanning electron microscopy techniques were used to characterize the composition and structure of PoPd/ZnO nanocomposites. The corrosion protection of polymer coatings ability was studied by Eocp-time measurement, anodic and cathodic potentiodynamic polarization and impedance techniques in 3.5% NaCl as corrosive solution. It was found that ZnO nanoparticles improve the barrier and electrochemical anticorrosive properties of poly(o-phenylenediamine.

Formation of a cerium conversion coating on magnesium alloy using ascorbic acid as additive. Characterisation and anticorrosive properties of the formed films

Directory of Open Access Journals (Sweden)

A.P. Loperena

2016-12-01

The presence of HAsc in the conversion solution causes changes in the morphology, adherence and anticorrosive performance of the films. The improvement in the corrosion resistance is closely associated with the corrosion inhibition properties of HAsc.

Fabrication of anticorrosive multilayer onto magnesium alloy substrates via spin-assisted layer-by-layer technique

Energy Technology Data Exchange (ETDEWEB)

Cai Kaiyong, E-mail: Kaiyong_cai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Sui Xiaojing; Hu Yan [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Zhao Li [China National Centre for Biotechnology Development, No. 16, Xi Si Huan Zhong Lu, Haidian District, Beijing 100036 (China); Lai Min; Luo Zhong; Liu Peng; Yang Weihu [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China)

2011-12-01

To improve the corrosion resistance of magnesium alloy, we reported a novel approach for the fabrication of anticorrosive multilayers onto AZ91D substrates. The multilayers were composed of poly(ethylene imine) (PEI), poly(styrene sulfonate) (PSS) and 8-hydroxyquinoline (8HQ). They were deposited onto AZ91D substrates via a spin-assisted layer-by-layer (LbL) technique. The multilayered structure was stabilized with glutaraldehyde (GA) as crossing linker. It was confirmed by Fourier transform infrared spectroscopy (FT-IR). Surface morphologies and elemental compositions of the formed anticorrosive multilayers were characterized with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The corrosion performance of the multilayer coated AZ91D substrates was characterized by hydrogen evolution. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements suggested that the multilayered coating improved the corrosion resistance of AZ91D substrates. In vitro study revealed that the multilayered coating was cytocompatible. The study provides a potential alternative for the fabrication of corrosion resistant magnesium alloy-based implants. Highlights: {yields} Corrosion protective multilayers have been constructed onto AZ91D substrates via layer by layer technique. {yields} The multilayered structured containing 8-hydroxyquinoline highly improves the corrosion resistance of AZ91D substrates. {yields} The novel multilayered coating is potentially important for developing corrosion resistant magnesium alloy-based implants.

Fabrication of anticorrosive multilayer onto magnesium alloy substrates via spin-assisted layer-by-layer technique

International Nuclear Information System (INIS)

Cai Kaiyong; Sui Xiaojing; Hu Yan; Zhao Li; Lai Min; Luo Zhong; Liu Peng; Yang Weihu

2011-01-01

To improve the corrosion resistance of magnesium alloy, we reported a novel approach for the fabrication of anticorrosive multilayers onto AZ91D substrates. The multilayers were composed of poly(ethylene imine) (PEI), poly(styrene sulfonate) (PSS) and 8-hydroxyquinoline (8HQ). They were deposited onto AZ91D substrates via a spin-assisted layer-by-layer (LbL) technique. The multilayered structure was stabilized with glutaraldehyde (GA) as crossing linker. It was confirmed by Fourier transform infrared spectroscopy (FT-IR). Surface morphologies and elemental compositions of the formed anticorrosive multilayers were characterized with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The corrosion performance of the multilayer coated AZ91D substrates was characterized by hydrogen evolution. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements suggested that the multilayered coating improved the corrosion resistance of AZ91D substrates. In vitro study revealed that the multilayered coating was cytocompatible. The study provides a potential alternative for the fabrication of corrosion resistant magnesium alloy-based implants. Highlights: → Corrosion protective multilayers have been constructed onto AZ91D substrates via layer by layer technique. → The multilayered structured containing 8-hydroxyquinoline highly improves the corrosion resistance of AZ91D substrates. → The novel multilayered coating is potentially important for developing corrosion resistant magnesium alloy-based implants.

Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

Science.gov (United States)

Cui, Mingjun; Ren, Siming; Chen, Jia; Liu, Shuan; Zhang, Guangan; Zhao, Haichao; Wang, Liping; Xue, Qunji

2017-03-01

Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT-) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT-, as proved by Raman and UV-vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 106 Ω cm2) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

Science.gov (United States)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

Preparation of silver-cuprous oxide/stearic acid composite coating with superhydrophobicity on copper substrate and evaluation of its friction-reducing and anticorrosion abilities

Energy Technology Data Exchange (ETDEWEB)

Li, Peipei [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Chen, Xinhua [College of Chemistry and Chemical Engineering, Xuchang University, Xuchang 461000 (China); Yang, Guangbin; Yu, Laigui [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zhang, Pingyu, E-mail: pingyu@henu.edu.cn [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China)

2014-01-15

A simple two-step solution immersion process was combined with surface-modification by stearic acid to prepare superhydrophobic coatings on copper substrates so as to reduce friction coefficient, increase wear resistance and improve the anticorrosion ability of copper. Briefly, cuprous oxide (Cu{sub 2}O) crystal coating with uniform and compact tetrahedron structure was firstly created by immersing copper substrate in 2 mol L{sup −1} NaOH solution. As-obtained Cu{sub 2}O coating was then immersed in 0.33 mmol L{sup −1} AgNO{sub 3} solution to incorporate silver nanoparticles, followed by modification with stearic acid (denoted as SA) coating to achieve hydrophobicity. The surface morphology and chemical composition of silver-cuprous oxide/stearic acid (denoted as Ag-Cu{sub 2}O/SA) composite coating were investigated using a scanning electron microscope and an X-ray photoelectron spectroscope (XPS); and its phase structure was examined with an X-ray diffractometer (XRD). Moreover, the contact angle of water on as-prepared Ag-Cu{sub 2}O/SA composite coating was measured, and its friction-reducing and anticorrosion abilities were evaluated. It was found that as-prepared Ag-Cu{sub 2}O/SA composite coating has a water contact angle of as high as 152.4{sup o} and can provide effective friction-reducing, wear protection and anticorrosion protection for copper substrate, showing great potential for surface-modification of copper.

Effect of perfluorodecyltrichlorosilane on the surface properties and anti-corrosion behavior of poly(dimethylsiloxane)-ZnO coatings

Science.gov (United States)

Arukalam, Innocent O.; Meng, Meijiang; Xiao, Haigang; Ma, Yuantai; Oguzie, Emeka E.; Li, Ying

2018-03-01

Poly(dimethylsiloxane)-ZnO coatings modified with different amounts of perfluorodecyltrichlorosilane (FDTS) were prepared using sol-gel technique. The results of field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) examinations showed that the surface structures and roughness of the coatings were respectively influenced by the increasing addition of FDTS. The water contact angle measurements showed maximum value of 130.52° with the 0.10 g FDTS-modified coating sample. The X-ray photoelectron spectroscopy (XPS) results indicated the coatings' hydrophobicity was also influenced by surface chemistry. The FTIR-ATR characterization results showed there was remarkable increase in the crystallinity of 0.10 g FDTS-modified coating after modification, and was confirmed by differential scanning calorimetry (DSC) analysis of crystallization temperature and the X-ray diffraction (XRD) results with an estimation of 71.29% percent crystallinity. The mechanical properties of the coatings were also conducted. The EIS measurements for anti-corrosion behavior showed that 0.10 g FDTS-modified coating had the highest barrier performance and lowest rate of degradation. Indeed, the obtained data have demonstrated that 0.10 g (≈ 0.18%) FDTS produced the most significantly effect on the surface and barrier properties of the coatings and thus, can effectively be used for anti-corrosion application in the marine environments.

Process, structure, property and applications of metallic glasses

Directory of Open Access Journals (Sweden)

B. Geetha Priyadarshini

2016-07-01

Full Text Available Metallic glasses (MGs are gaining immense technological significance due to their unique structure-property relationship with renewed interest in diverse field of applications including biomedical implants, commercial products, machinery parts, and micro-electro-mechanical systems (MEMS. Various processing routes have been adopted to fabricate MGs with short-range ordering which is believed to be the genesis of unique structure. Understanding the structure of these unique materials is a long-standing unsolved mystery. Unlike crystalline counterpart, the outstanding properties of metallic glasses owing to the absence of grain boundaries is reported to exhibit high hardness, excellent strength, high elastic strain, and anti-corrosion properties. The combination of these remarkable properties would significantly contribute to improvement of performance and reliability of these materials when incorporated as bio-implants. The nucleation and growth of metallic glasses is driven by thermodynamics and kinetics in non-equilibrium conditions. This comprehensive review article discusses the various attributes of metallic glasses with an aim to understand the fundamentals of relationship process-structure-property existing in such unique class of material.

Smart pigging - a contribution to the monitoring of the anti-corrosion protection systems on pig-inspectable high-pressure gas transmission pipelines; Intelligente Molchung - ein Beitrag zur Ueberwachung des Korrosionsschutzes molchbarer Gashochdruckleitungen

Energy Technology Data Exchange (ETDEWEB)

Ahlers, M.; Schoeneich, H.G. [Ruhrgas AG, Essen (Germany). Kompetenz-Center Korrosionsschutz

2000-07-01

High-pressure gas transmission pipelines installed underground are exposed to the risk of external corrosion. The application of a sheathing (passive protection) and, since the 1950s, the installation of a cathodic anti-corrosion protection system, provide pipelines with effective protection against this danger. In the past, the effectiveness of cathodic anti-corrosion protection systems was verified by means of intensive measuring and re-measuring cycles. It became apparent that points of damage to the sheathing were protected in the majority of cases against corrosion by the cathodic anti-corrosion protection system. There are, however, particular design circumstances and ambient conditions which can make this anti-corrosion protection concept either partially or completely ineffective. The use of smart pigs for inspection of pig-inspectable gas transmission pipelines makes it possible to detect and eliminate these weak points. (orig.) [German] Gashochdruckleitungen, die im Erdboden verlegt werden, unterliegen einer Gefaehrdung durch Aussenkorrosion. Durch eine Umhuellung (passiver Schutz) und seit den 50er Jahren durch die Einrichtung des kathodischen Korrosionsschutzes (aktiver Schutz) sind die Leitungen gegen diese Gefaehrdung wirkungsvoll geschuetzt. In der Vergangenheit wurde die Ueberpruefung der Wirksamkeit des kathodischen Korrosionsschutzes durch Intensivmessungen und Nachmessungen sichergestellt. Dabei zeigte sich, dass in der ueberwiegenden Zahl Umhuellungsbeschaedigungen durch den kathodischen Korrosionsschutz gegen Korrosion geschuetzt sind. Es gibt jedoch besondere konstruktive oder Umgebungsbedingungen, die dieses Korrosionsschuzkonzept teilweise oder vollstaendig unwirksam werden lassen. Mit dem Einsatz von intelligenten Molchen zur Inspektion molchbarer Gastransportleitungen koennen diese Schwachstellen erkannt und beseitigt werden. (orig.)

Synergistic effect of PANI-ZrO2 composite as antibacterial, anti-corrosion, and phosphate adsorbent material: synthesis, characterization and applications.

Science.gov (United States)

Masim, Frances Camille P; Tsai, Cheng-Hsien; Lin, Yi-Feng; Fu, Ming-Lai; Liu, Minghua; Kang, Fei; Wang, Ya-Fen

2017-11-03

The increasing number of bacteria-related problems and presence of trace amounts of phosphate in treated wastewater effluents have become a growing concern in environmental research. The use of antibacterial agents and phosphate adsorbents for the treatment of wastewater effluents is of great importance. In this study, the potential applications of a synthesized polyaniline (PANI)-zirconium dioxide (ZrO 2 ) composite as an antibacterial, phosphate adsorbent and anti-corrosion material were systematically investigated. The results of an antibacterial test reveal an effective area of inhibition of 14 and 18 mm for the Escherichia coli and Staphylococcus aureus bacterial strains, respectively. The antibacterial efficiency of the PANI-ZrO 2 composite is twice that of commercial ZrO 2 . In particular, the introduction of PANI increased the specific surface area and roughness of the composite material, which was beneficial to increase the contact area with bacterial and phosphate. The experimental results demonstrated that phosphate adsorption studies using 200 mg P/L phosphate solution showed a significant phosphate removal efficiency of 64.4%, and the maximum adsorption capacity of phosphate on the solid surface of PANI-ZrO 2 is 32.4 mg P/g. Furthermore, PANI-ZrO 2 coated on iron substrate was tested for anti-corrosion studies by a natural salt spray test (7.5% NaCl), which resulted in the formation of no rust. To the best of our knowledge, no works have been reported on the synergistic effects of the PANI-ZrO 2 composite as an antibacterial, anti-corrosion, and phosphate adsorbent material. PANI-ZrO 2 composite is expected to be a promising comprehensive treatment method for water filters in the aquaculture industry and for use in water purification applications.

Complex anticorrosion coating for ZK30 magnesium alloy

International Nuclear Information System (INIS)

Lamaka, S.V.; Knoernschild, G.; Snihirova, D.V.; Taryba, M.G.; Zheludkevich, M.L.; Ferreira, M.G.S.

2009-01-01

This work aims at developing a new complex anticorrosion protection system for ZK30 magnesium alloy. This protective coating is based on an anodic oxide layer loaded with corrosion inhibitors in its pores, which is then sealed with a sol-gel hybrid polymer. The porous oxide layer is produced by spark anodizing. The sol-gel film shows good adhesion to the oxide layer as it penetrates through the pores of the anodized layer forming an additional transient oxide-sol-gel interlayer. The thickness of this complex protective coating is about 3.7-7.0 μm. A blank oxide-sol-gel coating system or one doped with Ce 3+ ions proved to be effective corrosion protection for the magnesium alloy preventing corrosion attack after exposure for a relatively long duration in an aggressive NaCl solution. The structure and the thickness of the anodized layer and the sol-gel film were characterized by scanning electron microscopy (SEM). The corrosion behaviour of the ZK30 substrates pre-treated with the complex coating was tested by electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET), and scanning ion-selective electrode techniques (SIET).

Roles of Co element in Fe-based bulk metallic glasses utilizing industrial FeB alloy as raw material

Directory of Open Access Journals (Sweden)

Shouyuan Wang

2017-08-01

Full Text Available A series of Fe-based bulk metallic glasses were fabricated by a conventional copper mold casting method using a kind of Fe-B industrial raw alloy. It is found that Fe-B-Y-Nb bulk metallic glass with 3 at% of Co addition possesses the best glass forming ability, thermal stability, hardness, magnetic property and anti-corrosion property. The hardness test result indicates a synchronically trend with glass-forming ability parameters. The excellent glass-forming ability and a combination of good mechanical and functional properties suggest that the alloys in this work might be good candidates for commercial use.

Anticorrosive Performance of Zinc Phosphate Coatings on Mild Steel Developed Using Galvanic Coupling

Directory of Open Access Journals (Sweden)

M. Arthanareeswari

2013-01-01

Full Text Available The anticorrosive performance of zinc phosphate coatings developed by galvanic coupling technique on mild steel substrates using the cathode materials such as titanium (Ti, copper (Cu, brass (BR, nickel (Ni, and stainless steel (SS is elucidated in this study. Thermal and chemical stability tests, immersion test in 3.5% NaCl, ARE salt droplet test, and salt spray test were carried out. The study reveals that the mild steel substrates phosphated under galvanically coupled condition showed better corrosion resistance than the one coated without coupling. The open circuit potential (OCP of phosphated mild steel panels in 3.5% NaCl was found to be a function of phosphate coating weight and porosity of the coating.

Actively convected liquid metal divertor

International Nuclear Information System (INIS)

Shimada, Michiya; Hirooka, Yoshi

2014-01-01

The use of actively convected liquid metals with j × B force is proposed to facilitate heat handling by the divertor, a challenging issue associated with magnetic fusion experiments such as ITER. This issue will be aggravated even more for DEMO and power reactors because the divertor heat load will be significantly higher and yet the use of copper would not be allowed as the heat sink material. Instead, reduced activation ferritic/martensitic steel alloys with heat conductivities substantially lower than that of copper, will be used as the structural materials. The present proposal is to fill the lower part of the vacuum vessel with liquid metals with relatively low melting points and low chemical activities including Ga and Sn. The divertor modules, equipped with electrodes and cooling tubes, are immersed in the liquid metal. The electrode, placed in the middle of the liquid metal, can be biased positively or negatively with respect to the module. The j × B force due to the current between the electrode and the module provides a rotating motion for the liquid metal around the electrodes. The rise in liquid temperature at the separatrix hit point can be maintained at acceptable levels from the operation point of view. As the rotation speed increases, the current in the liquid metal is expected to decrease due to the v × B electromotive force. This rotating motion in the poloidal plane will reduce the divertor heat load significantly. Another important benefit of the convected liquid metal divertor is the fast recovery from unmitigated disruptions. Also, the liquid metal divertor concept eliminates the erosion problem. (letter)

Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers

DEFF Research Database (Denmark)

Sørensen, Per Aggerholm; Weinell, C. E.; Dam-Johansen, Kim

2010-01-01

Cathodic delamination is one of the major modes of failure for anticorrosive coatings subjected to a physical damage and immersed in seawater. The cause of cathodic delamination has been reported to be the result of a chemical attack at the coating-steel interface by free radicals and peroxides...... formed as intermediates in the cathodic reaction during the corrosion process. In this study, antioxidants (i.e., free radical scavengers and peroxide decomposers) have been incorporated into various generic types of coatings to investigate the effect of antioxidants on the rate of cathodic delamination...... of epoxy coatings on cold rolled steel. The addition of free radical scavengers to epoxy coatings improved the resistance toward cathodic delamination by up to 50% during seawater immersion, while peroxide decomposers had a limited effect. Testing using substrates prepared from stainless steel...

Novel Thiol-Ene Hybrid Coating for Metal Protection

Directory of Open Access Journals (Sweden)

Mona Taghavikish

2016-04-01

Full Text Available A novel hybrid anticorrosion coating with dual network of inorganic (Si–O–Si and organic bonds (C–S–C was prepared on metal through an in situ sol-gel and thiol-ene click reaction. This novel interfacial thin film coating incorporates (3-mercaptopropyl trimethoxysilane (MPTS and 1,4-di(vinylimidazolium butane bisbromide based polymerizable ionic liquid (PIL to form a thiol-ene based photo-polymerized film, which on subsequent sol-gel reaction forms a thin hybrid interfacial layer on metal surface. On top of this PIL hybrid film, a self-assembled nanophase particle (SNAP coating was employed to prepare a multilayer thin film coating for better corrosion protection and barrier performance. The novel PIL hybrid film was characterised for structure and properties using Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, and thermogravimetric analysis (TGA. The corrosion protection performance of the multilayer coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. The results reveal that this novel double layer coating on metal offers excellent protection against corrosion and has remarkably improved the barrier effect of the coating.

Activation volume and interaction of metal particulate media

Energy Technology Data Exchange (ETDEWEB)

Tetsukawa, Hiroki [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Kondo, Hirofumi [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

2005-09-15

We have investigated the activation volume (V{sub ac}) and magnetostatic interaction of metal particulate (MP) media. The activation volume of MP media decreases with the decrease of physical volume (V{sub phy}) of metal particles. The activation volume and the ratio of V{sub phy}/V{sub ac} of advanced metal particles are 6x10{sup -24}m{sup 3} and 1.5, respectively. It can be predicted that the physical volume of metal particle is about 3x10{sup -24}m{sup 3} when the physical volume is equal to the activation volume. This value is agreement with the practical lower limit of physical volume of metal particle predicted by Sharrock. The negative interaction (demagnetization effect) in MP media decreases with low saturation magnetization of the metal particles, a thin magnetic layer, a high orientation of MP media, and a low packing fraction of metal particles in the MP media. The activation volume of the MP media decreased as the negative interactions decreased. In advanced MP media with low M{sub r}.t (M{sub r}=remanent magnetization and t=thickness), the influence of interaction on the activation volume is reduced.

Activation volume and interaction of metal particulate media

International Nuclear Information System (INIS)

Tetsukawa, Hiroki; Kondo, Hirofumi

2005-01-01

We have investigated the activation volume (V ac ) and magnetostatic interaction of metal particulate (MP) media. The activation volume of MP media decreases with the decrease of physical volume (V phy ) of metal particles. The activation volume and the ratio of V phy /V ac of advanced metal particles are 6x10 -24 m 3 and 1.5, respectively. It can be predicted that the physical volume of metal particle is about 3x10 -24 m 3 when the physical volume is equal to the activation volume. This value is agreement with the practical lower limit of physical volume of metal particle predicted by Sharrock. The negative interaction (demagnetization effect) in MP media decreases with low saturation magnetization of the metal particles, a thin magnetic layer, a high orientation of MP media, and a low packing fraction of metal particles in the MP media. The activation volume of the MP media decreased as the negative interactions decreased. In advanced MP media with low M r .t (M r =remanent magnetization and t=thickness), the influence of interaction on the activation volume is reduced

Gallic Acid, Ellagic Acid and Pyrogallol Reaction with Metallic Iron

Energy Technology Data Exchange (ETDEWEB)

Jaen, J. A., E-mail: jjaen@ancon.up.ac.p [Universidad de Panama, Departamento de Quimica Fisica, Facultad de Ciencias Naturales, Exactas y Tecnologia (Panama); Gonzalez, L.; Vargas, A.; Olave, G. [Universidad de Panama, Escuela de Quimica, Facultad de Ciencias Naturales, Exactas y Tecnologia (Panama)

2003-06-15

The reaction between gallic acid, ellagic acid and pyrogallol with metallic iron was studied using infrared and Moessbauer spectroscopy. Most hydrolysable tannins with interesting anticorrosive or inhibition properties are structurally related to these compounds, thus they may be used as models for the study of hydrolysable tannins and related polyphenols. The interaction was followed up to 3 months. Results indicated two different behaviors. At polyphenol concentrations higher than 1% iron converts to sparingly soluble and amorphous ferric (and ferrous) polyphenolate complexes. At lower concentrations (0.1%), the hydrolysis reactions are dominant, resulting in the formation of oxyhydroxides, which can be further reduced to compounds like magnetite by the polyphenols.

Gallic Acid, Ellagic Acid and Pyrogallol Reaction with Metallic Iron

International Nuclear Information System (INIS)

Jaen, J. A.; Gonzalez, L.; Vargas, A.; Olave, G.

2003-01-01

The reaction between gallic acid, ellagic acid and pyrogallol with metallic iron was studied using infrared and Moessbauer spectroscopy. Most hydrolysable tannins with interesting anticorrosive or inhibition properties are structurally related to these compounds, thus they may be used as models for the study of hydrolysable tannins and related polyphenols. The interaction was followed up to 3 months. Results indicated two different behaviors. At polyphenol concentrations higher than 1% iron converts to sparingly soluble and amorphous ferric (and ferrous) polyphenolate complexes. At lower concentrations (0.1%), the hydrolysis reactions are dominant, resulting in the formation of oxyhydroxides, which can be further reduced to compounds like magnetite by the polyphenols.

Antimicrobial action and anti-corrosion effect against sulfate reducing bacteria by lemongrass (Cymbopogon citratus) essential oil and its major component, the citral.

Science.gov (United States)

Korenblum, Elisa; Regina de Vasconcelos Goulart, Fátima; de Almeida Rodrigues, Igor; Abreu, Fernanda; Lins, Ulysses; Alves, Péricles Barreto; Blank, Arie Fitzgerald; Valoni, Erika; Sebastián, Gina V; Alviano, Daniela Sales; Alviano, Celuta Sales; Seldin, Lucy

2013-08-10

The anti-corrosion effect and the antimicrobial activity of lemongrass essential oil (LEO) against the planktonic and sessile growth of a sulfate reducing bacterium (SRB) were evaluated. Minimum inhibitory concentration (MIC) of LEO and its major component, the citral, was 0.17 mg ml-1. In addition, both LEO and citral showed an immediate killing effect against SRB in liquid medium, suggesting that citral is responsible for the antimicrobial activity of LEO against SRB. Transmission electron microscopy revealed that the MIC of LEO caused discernible cell membrane alterations and formed electron-dense inclusions. Neither biofilm formation nor corrosion was observed on carbon steel coupons after LEO treatment. LEO was effective for the control of the planktonic and sessile SRB growth and for the protection of carbon steel coupons against biocorrosion. The application of LEO as a potential biocide for SRB growth control in petroleum reservoirs and, consequently, for souring prevention, and/or as a coating protection against biocorrosion is of great interest for the petroleum industries.

The effect of the metal-on-metal hip controversy on internet search activity.

LENUS (Irish Health Repository)

Phelan, Nigel

2014-01-04

The recall of the articular surface replacement (ASR) hip prosthesis in 2010 represents one of the most controversial areas in orthopaedic surgery in recent years. The aim of this study was to compare the impact of the metal-on-metal hip controversy on Internet search activity in four different regions and determine whether the number of related news reports affected Internet search activity. The Google Trends, Keywords and News applications were used to record the number of news articles and Internet search activity for the terms "hip recall", "metal-on-metal hip" and "ASR hip" from October 2009 to October 2012 in the USA, the UK, Australia and Ireland. There was a large increase in search activity following the official recall in August 2010 in all countries. There was significantly greater search activity after the recall in Ireland compared with the UK for the search term "hip recall" (P = 0.004). For the term "metal-on-metal hip", the UK had significantly more search activity (P = 0.0009). There was a positive correlation between the number of news stories in UK and Ireland with Internet search activity but not in the USA or Australia. Differences between countries affected by the same recall highlight the complex effects of the media on public awareness. The data demonstrates a window of opportunity prior to the official recall for the development of an awareness campaign to provide patients with accurate information.

Breast milk metal ion levels in a young and active patient with a metal-on-metal hip prosthesis.

Science.gov (United States)

Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco

2013-01-01

Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. Copyright © 2013 Elsevier Inc. All rights reserved.

Economic Efficiency of Innovative Materials for Sectors of Economy

Directory of Open Access Journals (Sweden)

Miroshnikova Tatyana

2016-01-01

Full Text Available The paper proposes an approach to the assessment of the economic efficiency of innovative anti-corrosion coatings for sectors of the national economy of the Russia on the basis of a synthesis of strategic sectoral and cost analysis. According to the authors, a comparative analysis of composite polymeric anticorrosion protecting coatings with similar products, estimating of direct and indirect economic effect and prognosis of implementation, forms a deeper understanding of the role of innovative technologies in the Russian state development of import substitution, the investment attractiveness of Russian industries in the new part technologies, applied research activities of private companies. Metal consumption sectors of the economy were chosen as an object of research, as they are characterized by the use of the following products: industrial construction and reconstruction, nuclear and thermal power, chemical, oil and gas, utilities, food processing, automotive, shipbuilding, aviation and rocket science, other industry. Basic modeling of implementation of anticorrosion protecting coatings in industrial enterprises was carried out on the basis of generating energy enterprises as one of the main end-users of anti-corrosive materials that also issue accurate statements.

Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

Energy Technology Data Exchange (ETDEWEB)

Cui, Mingjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Ren, Siming [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Chen, Jia; Liu, Shuan [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhang, Guangan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao, Haichao, E-mail: zhaohaichao@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xue, Qunji, E-mail: qjxue@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

2017-03-01

Highlights: • Hexagonal boron nitride nanosheets were well dispersed by using water-soluble carboxylated aniline trimer as dispersant. • The best corrosion performance of waterborne epoxy coatings was achieved with the addition of 1 wt% h-BN. • The decrease of the pores and defects of coating matrix inhibits the diffusion and water absorption of corrosive medium in the coating. - Abstract: Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT{sup −}) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT{sup −}, as proved by Raman and UV–vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 10{sup 6} Ω cm{sup 2}) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

Assessment of Automotive Coatings Used on Different Metallic Substrates

Directory of Open Access Journals (Sweden)

W. Bensalah

2014-01-01

Full Text Available Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of different coating systems were conducted using pin on disc machine. Immersion tests were carried out in 5% NaCl and immersion tests in 3% NaOH solutions. Results showed which of the coating systems is more suitable for each substrate in terms of mechanical, tribological, and anticorrosive performance.

Corrosion and protection of metals in the rural atmosphere of El Pardo Spain (PATINA/CYTED project)

International Nuclear Information System (INIS)

Simancas, J.; Castano, J. G.; Morcillo, M.

2003-01-01

Atmospheric corrosion tests of metallic and organic coatings on steel, zinc and aluminium have been conducted in el Pardo (Spain) as part of the PATINA/CYTED project Anticorrosive Protection of Metals in the Atmosphere. This is a rural atmosphere with the following ISO corrosivity categories: C2 (Fe), C'' (Zn), Cu (Cu) and C1 (Al). Its average temperature and relative humidity is 13 degree centigrade and 62.8, respectively, and it has low SO 2 and C1''- contents. Results of 42 months exposure are discussed. Atmospheric exposure tests were carried out for the following types of coatings: conventional paint coatings for steel and hot-dip galvanized steel (group 1), new painting technologies for steel and galvanized steel (group 2), zinc-base metallic coatings (group 3), aluminium-base metallic coatings (group 4), coatings on aluminium (group 5) and coil-coatings on steel, hot-dip galvanized steel and 55% Al-Zn coated steel (group 6). (Author) 9 refs

Moessbauer spectroscopic study of corrosion products beneath primer coating containing anticorrosive pigments

International Nuclear Information System (INIS)

Kumar, A.V.R.; Nigam, R.K.

1998-01-01

The phase analysis of the rusts generated beneath the primer containing micaceous iron oxide (MIO) and micaceous iron oxide in combination with red lead (RL), zinc phosphate (ZP), basic lead silicochromate (BLSC) and zinc chromate (ZC) has been carried out by Moessbauer spectroscopy at room temperature. The rust beneath the coating obtained after immersion of the painted panel for six months in 3% NaCl, consists mainly of non-stoichiometric magnetite together with small fractions of γ-, α-FeOOH except in the case of panel painted with RL containing MIO showed only a central doublet indicating the formation of γ-FeOOH and SPM α-FeOOH. Non-stoichiometry of magnetite as calculated from the ratio of B/A sites of the peaks of magnetite in the spectrum has been found depending on the nature of anticorrosive pigment present in the primer coating. The order of non-stoichiometry has been found to be in order of ZC > BLSC > ZP > MIO. (author)

Biomimetic hydrophobic surface fabricated by chemical etching method from hierarchically structured magnesium alloy substrate

Energy Technology Data Exchange (ETDEWEB)

Liu, Yan; Yin, Xiaoming; Zhang, Jijia [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Wang, Yaming [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Han, Zhiwu, E-mail: zwhan@jlu.edu.cn [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Ren, Luquan [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China)

2013-09-01

As one of the lightest metal materials, magnesium alloy plays an important role in industry such as automobile, airplane and electronic product. However, magnesium alloy is hindered due to its high chemical activity and easily corroded. Here, inspired by typical plant surfaces such as lotus leaves and petals of red rose with super-hydrophobic character, the new hydrophobic surface is fabricated on magnesium alloy to improve anti-corrosion by two-step methodology. The procedure is that the samples are processed by laser first and then immersed and etched in the aqueous AgNO{sub 3} solution concentrations of 0.1 mol/L, 0.3 mol/L and 0.5 mol/L for different times of 15 s, 40 s and 60 s, respectively, finally modified by DTS (CH{sub 3}(CH{sub 2}){sub 11}Si(OCH{sub 3}){sub 3}). The microstructure, chemical composition, wettability and anti-corrosion are characterized by means of SEM, XPS, water contact angle measurement and electrochemical method. The hydrophobic surfaces with microscale crater-like and nanoscale flower-like binary structure are obtained. The low-energy material is contained in surface after DTS treatment. The contact angles could reach up to 138.4 ± 2°, which hydrophobic property is both related to the micro–nano binary structure and chemical composition. The results of electrochemical measurements show that anti-corrosion property of magnesium alloy is improved. Furthermore, our research is expected to create some ideas from natural enlightenment to improve anti-corrosion property of magnesium alloy while this method can be easily extended to other metal materials.

Synthesis of durable microcapsules for self-healing anticorrosive coatings: A comparison of selected methods

DEFF Research Database (Denmark)

Nesterova, Tatyana; Dam-Johansen, Kim; Kiil, Søren

2011-01-01

-based anticorrosive coatings, based on incorporation of microcapsules, filled with reactive agents, into the coating matrix, is investigated. Upon small damages to the coating, the reagents are released from the capsules and react, thereby forming a cross-linked network, which heals the crack. However......Self-healing materials have the ability to ‘repair’ themselves upon exposure to an external stimulus. In the field of coatings, extensive laboratory research has been conducted on these so-called smart materials in the last decade. In the present work, a self-healing concept for epoxy......, for the concept to work, microcapsules have to be strong enough to remain intact during storage and coating formulation and application. Furthermore, the capsules must remain stable for many years in the dry coating. Laboratory experiments, using four out of several encapsulation methods available...

Reduced Graphene Oxide Coating with Anticorrosion and Electrochemical Property-Enhancing Effects Applied in Hydrogen Storage System.

Science.gov (United States)

Du, Yi; Li, Na; Zhang, Tong-Ling; Feng, Qing-Ping; Du, Qian; Wu, Xing-Hua; Huang, Gui-Wen

2017-08-30

Low-capacity retention is the most prominent problem of the magnesium nickel alloy (Mg 2 Ni), which prevents it from being commercially applied. Here, we propose a practical method for enhancing the cycle stability of the Mg 2 Ni alloy. Reduced graphene oxide (rGO) possesses a graphene-based structure, which could provide high-quality barriers that block the hydroxyl in the aqueous electrolyte; it also possesses good hydrophilicity. rGO has been successfully coated on the amorphous-structured Mg 2 Ni alloy via electrostatic assembly to form the rGO-encapsulated Mg 2 Ni alloy composite (rGO/Mg 2 Ni). The experimental results show that ζ potentials of rGO and the modified Mg 2 Ni alloy are totally opposite in water, with values of -11.0 and +22.4 mV, respectively. The crumpled structure of rGO sheets and the contents of the carbon element on the surface of the alloy are measured using scanning electron microscopy, transmission electron microscopy, and energy dispersive spectrometry. The Tafel polarization test indicates that the rGO/Mg 2 Ni system exhibits a much higher anticorrosion ability against the alkaline solution during charging/discharging. As a result, high-capacity retentions of 94% (557 mAh g -1 ) at the 10th cycle and 60% (358 mAh g -1 ) at the 50th cycle have been achieved, which are much higher than the results on Mg 2 Ni capacity retention combined with the absolute value reported so far to our knowledge. In addition, both the charge-transfer reaction rate and the hydrogen diffusion rate are proven to be boosted with the rGO encapsulation. Overall, this work demonstrates the effective anticorrosion and electrochemical property-enhancing effects of rGO coating and shows its applicability in the Mg-based hydrogen storage system.

Report on results concerning development of supermetal technology, R and D of offshore oil production supporting system, and development of technology for aluminum-based high-anticorrosive microstructured metallic material (FY2000); Super metal no gijutsu kaihatsu seika hokokusho (2000 nendo). Kaitei sekiyu seisan shien system kenkyu kaihatsu (Aluminium kei kotaishokusei bisai kozo seigyo kinzoku zairyo gijutsu kaihatsu)

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

With the purpose of developing high strength and high-anticorrosive aluminum-based material through microstructure control, R and D was conducted, with fiscal 2000 results compiled. In the research of grain refinement mechanism, molten metal rolled stock was experimentally produced in which Mg content was varied 0-2.5 mass % with Al-2.5 mass % Mn as its base. As a result, a microstructure with an average grain size of about 3 {mu}m was obtained by processing the alloy through homogenization at 550 degrees C, cold rolling by 91% and the final treatment at 350 degrees C without Mg addition. Addition of Mg increased square grain boundaries in the microstructure, raising proof stress to about 180 MPa in Al-2.5%Mn-2.5%Mg alloy. In the research of development of the machining process, a rapid heating process was performed on a typical aluminum alloy, with the effect examined, by an alloy system or a plate thickness, on the electric power used and on the temperature reached. A rapidly heated aluminum alloy plate turned to have a microstructure with equi-axed grains of a uniform size, compared with a salt bath processed material heated at the same temperature. (NEDO)

Antimicrobial action and anti-corrosion effect against sulfate reducing bacteria by lemongrass (Cymbopogon citratus) essential oil and its major component, the citral

Science.gov (United States)

2013-01-01

The anti-corrosion effect and the antimicrobial activity of lemongrass essential oil (LEO) against the planktonic and sessile growth of a sulfate reducing bacterium (SRB) were evaluated. Minimum inhibitory concentration (MIC) of LEO and its major component, the citral, was 0.17 mg ml-1. In addition, both LEO and citral showed an immediate killing effect against SRB in liquid medium, suggesting that citral is responsible for the antimicrobial activity of LEO against SRB. Transmission electron microscopy revealed that the MIC of LEO caused discernible cell membrane alterations and formed electron-dense inclusions. Neither biofilm formation nor corrosion was observed on carbon steel coupons after LEO treatment. LEO was effective for the control of the planktonic and sessile SRB growth and for the protection of carbon steel coupons against biocorrosion. The application of LEO as a potential biocide for SRB growth control in petroleum reservoirs and, consequently, for souring prevention, and/or as a coating protection against biocorrosion is of great interest for the petroleum industries. PMID:23938023

Adsorption of alginate and albumin on aluminum coatings inhibits adhesion of Escherichia coli and enhances the anti-corrosion performances of the coatings

Energy Technology Data Exchange (ETDEWEB)

He, Xiaoyan; Liu, Yi; Huang, Jing; Chen, Xiuyong; Ren, Kun; Li, Hua, E-mail: lihua@nimte.ac.cn

2015-03-30

Graphical abstract: - Highlights: • Adsorption behaviors of alginate and albumin on Al coatings were investigated at molecular level. • The adsorption inhibits effectively the colonization of Escherichia coli bacteria. • The adsorption alters the wettability of the Al coatings. • The conditioning layer enhances anti-corrosion performances of the Al coatings. - Abstract: Thermal-sprayed aluminum coatings have been extensively used as protective layers against corrosion for steel structures in the marine environment. The corrosion usually deteriorates from marine biofouling, yet the mechanism of accelerated corrosion of the coatings remains elusive. As the first stage participating in biofouling process, adsorption of molecules plays critical roles in mediating formation of biofilm. Here, we report at molecular level the adsorption behaviors of albumin and marine polysaccharide on arc-sprayed aluminum coatings and their influence on adhesion of Escherichia coli. The adsorption of alginate and albumin was characterized by infrared spectra analyses and atomic force microscopic observation. The adsorption inhibits effectively adhesion of the bacteria. Further investigation indicates that alginate/albumin altered the hydrophilicity/hydrophobicity of the coatings instead of impacting the survival of the bacteria to decline their adhesion. The conditioning layer composed of the molecules enhances anti-corrosion performances of the coatings.

Adsorption of alginate and albumin on aluminum coatings inhibits adhesion of Escherichia coli and enhances the anti-corrosion performances of the coatings

International Nuclear Information System (INIS)

He, Xiaoyan; Liu, Yi; Huang, Jing; Chen, Xiuyong; Ren, Kun; Li, Hua

2015-01-01

Graphical abstract: - Highlights: • Adsorption behaviors of alginate and albumin on Al coatings were investigated at molecular level. • The adsorption inhibits effectively the colonization of Escherichia coli bacteria. • The adsorption alters the wettability of the Al coatings. • The conditioning layer enhances anti-corrosion performances of the Al coatings. - Abstract: Thermal-sprayed aluminum coatings have been extensively used as protective layers against corrosion for steel structures in the marine environment. The corrosion usually deteriorates from marine biofouling, yet the mechanism of accelerated corrosion of the coatings remains elusive. As the first stage participating in biofouling process, adsorption of molecules plays critical roles in mediating formation of biofilm. Here, we report at molecular level the adsorption behaviors of albumin and marine polysaccharide on arc-sprayed aluminum coatings and their influence on adhesion of Escherichia coli. The adsorption of alginate and albumin was characterized by infrared spectra analyses and atomic force microscopic observation. The adsorption inhibits effectively adhesion of the bacteria. Further investigation indicates that alginate/albumin altered the hydrophilicity/hydrophobicity of the coatings instead of impacting the survival of the bacteria to decline their adhesion. The conditioning layer composed of the molecules enhances anti-corrosion performances of the coatings

A study on corrosive behavior of spring steel by shot-peening process

International Nuclear Information System (INIS)

An, Jae Pil; Park, Keyung Dong

2004-01-01

In this study, the influence of shot peening on the corrosion was investigated on spring steel immersed in 3.5% NaCl. The immersion test was performed on the two kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated. In case of corrosion potential, shot peened specimen shows more activated negative direction as compared with parent metal. Surface of specimen, which is treated with the shot peened, is placed as more activated state against inner base metal. It can cause the anti-corrosion effect on the base metal

Metal ion effects on enolase activity

International Nuclear Information System (INIS)

Lee, M.E.; Nowak, T.

1986-01-01

Most metal binding studies with yeast enolase suggest that two metals per monomer are required for catalytic activity. The functions of metal I and metal II have not been unequivocally defined. In a series of kinetic experiments where the concentration of MgII is kept constant at subsaturating levels (1mM), the addition of MnII or of ZnII gives a hyperbolic decrease in activity. The final velocity of these mixed metal systems is the same velocity obtained with either only MnII or ZnII respectively. The concentration of MnII (40 μM) or of Zn (2μM) which gives half maximal effect in the presence of (1mM) MgII is approximately the same as the Km' value for MnII (9μM) or ZnII (3μM) respectively. Direct binding of MnII to enolase in the absence and presence of MgII shows that MnII and MgII compete for the same metal site on enolase. In the presence of 2-phosphoglycerate (2-PGA) and MgII, only a single site is occupied by MnII. Results suggest MnII at site I and MgII at site II. PRR and high resolution 1 H and 31 P NMR studies of enzyme-ligand complexes containing MnII and MgII and MnII are consistent with this model. 31 P measurements allow a measure of the equilibrium constant (0.36) for enolase. Saturation transfer measurements yield net rate constants (k/sub f/ = 0.49s -1 ; k/sub r/ = 1.3s -1 ) for the overall reaction. These values are smaller than k/sub cat/ (38s -1 ) measured under analogous conditions. The cation at site I appears to determine catalytic activity

Activation and discharge kinetics of metal hydride electrodes

Energy Technology Data Exchange (ETDEWEB)

Johnsen, Stein Egil

2003-07-01

Potential step chronoamperometry and Electrochemical Impedance Spectroscopy (eis) measurements were performed on single metal hydride particles. For the {alpha}-phase, the bulk diffusion coefficient and the absorption/adsorption rate parameters were determined. Materials produced by atomisation, melt spinning and conventional casting were investigated. The melt spun and conventional cast materials were identical and the atomised material similar in composition. The particles from the cast and the melt spun material were shaped like parallelepipeds. A corresponding equation, for this geometry, for diffusion coupled to an absorption/adsorption reaction was developed. It was found that materials produced by melt spinning exhibited lower bulk diffusion (1.7E-14 m2/s) and absorption/adsorption reaction rate (1.0E-8 m/s), compared to materials produced by conventionally casting (1.1E-13 m2/s and 5.5E-8 m/s respectively). In addition, the influence of particle active surface and relative diffusion length were discussed. It was concluded that there are uncertainties connected to these properties, which may explain the large distribution in the kinetic parameters measured on metal hydride particles. Activation of metal hydride forming materials has been studied and an activation procedure, for porous electrodes, was investigated. Cathodic polarisation of the electrode during a hot alkaline surface treatment gave the maximum discharge capacity on the first discharge of the electrode. The studied materials were produced by gas atomisation and the spherical shape was retained during the activation. Both an AB{sub 5} and an AB{sub 2} alloy was successfully activated and discharge rate properties determined. The AB{sub 2} material showed a higher maximum discharge capacity, but poor rate properties, compared to the AB{sub 5} material. Reduction of surface oxides, and at the same time protection against corrosion of active metallic nickel, can explain the satisfying results of

Anti-corrosive Effects of Multi-Walled Carbon Nano Tube and Zinc Particle Shapes on Zinc Ethyl Silicate Coated Carbon Steel

Energy Technology Data Exchange (ETDEWEB)

Jang, JiMan; Shon, MinYoung; Kwak, SamTak [Pukyong National University, Busan (Korea, Republic of)

2016-01-15

Zinc ethyl silicate coatings containing multi walled carbon nanotubes (MWCNTs) were prepared, to which we added spherical and flake shaped zinc particles. The anti-corrosive effects of MWCNTs and zinc shapes on the zinc ethyl silicate coated carbon steel was examined, using electrochemical impedance spectroscopy and corrosion potential measurement. The results of EIS and corrosion potential measurement showed that the zinc ethyl silicate coated with flake shaped zinc particles and MWCNT showed lesser protection to corrosion. These outcomes were in agreement with previous results of corrosion potential and corrosion occurrence.

Anticorrosive organic/inorganic hybrid coatings

Science.gov (United States)

Gao, Tongzhai

Organic/inorganic hybrid coating system was developed for anticorrosion applications using polyurea, polyurethane or epoxide as the organic phase and polysiloxane, formed by sol-gel process, as the inorganic phase. Polyurea/polysiloxane hybrid coatings were formulated and moisture cured using HDI isocyanurate, alkoxysilane-functionalized HDI isocyanurate, and tetraethyl orthosilicate (TEOS) oligomers. Two urethanes were prepared using the same components as abovementioned in addition to the oligoesters derived from either cyclohexane diacids (CHDA) and 2-butyl-2-ethyl-1,3-propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6-hexanediol (HD), and trimethylol propane (TMP). Accelerated weathering and outdoor exposure were performed to study the weatherability of the polyurethane/polysiloxane hybrid coating system. FTIR and solid-state 13C NMR revealed that the degradation of the hybrid coatings occurred at the urethane and ester functionalities of the organic phase. DMA and DSC analyses showed the glass transition temperature increased and broadened after weathering. SEM was employed to observe the change of morphology of the hybrid coatings and correlated with the gloss variation after weathering. Rutile TiO2 was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the effect of pigmentation on the coating properties and the sol-gel precursor. Chemical interaction between the TiO2 and the sol-gel precursor was investigated using solid-state 29Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings were evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment were observed to be well dispersed in the polymer matrix. The thermal stability, the tensile modulus and strength of the coatings were enhanced with increasing PVC, whereas the pull-off adhesion and flexibility were reduced with increasing PVC. Finally, the pigmented coatings were

Study of a new possibility to predict the behavior of high - performance anticorrosive protections applied on steel after their exposure in natural aggressive environments, respectively in laboratory accelerated conditions

Directory of Open Access Journals (Sweden)

Irina POPA

2014-12-01

Full Text Available As a result of the global warming, notable changes in the climatic regime of Romania were observed in the last 40-50 years by increasing of the maximum temperatures and decreasing of the minimum temperatures characteristic for each season. This paper makes reference to an experimental research regarding the actual severity of the Romanian climate and its effects toward some performant anticorrosive coatings applied on steel. Such performant anticorrosive protection systems were exposed in situ – marine and alpine environment - and in parallel, aiming to simulate the severe climatic actions through laboratory accelerated environments - neutral salt fog, condensation and temperature variations. The graphical representation and the interpretation of the adhesion to the steel surface by means of the variation of the class into which the paint was framed after performing the cross-cut test during the exposure provided information concerning a new possibility to predict the evolution of the degradation of the paint, by means of this characteristic experimentally determined.

Anticorrosive field joint coating qualification, heat shrinkable sleeve; Qualificacao de revestimento anticorrosivo para juntas de campo, mantas termocontrateis

Energy Technology Data Exchange (ETDEWEB)

Cabral, Glaucia B.; Koebsch, Andre; Castinheiras Junior, Wilson [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2005-07-01

The main objective of this job is to present the quality requirements fixed by PETROBRAS for anticorrosive field joint coating for buried pipelines, industrially coated with PE-3L. It describes the used system - polyethylene based heat shrinkable sleeve - comparing with the existent on the pipeline. So, it exposes the suppliers' qualification stages, which include test carried out for the materials, for the sleeve set and for the coating after its application on the joint field. Finally, it shows that the experience, which has been gotten in the qualification, consolidated the quality control systematic that have been carry out during the sleeves acquisition and application at the pipeline construction. (author)

Anticorrosive Behavior and Porosity of Tricationic Phosphate and Zirconium Conversion Coating on Galvanized Steel

Science.gov (United States)

Velasquez, Camilo S.; Pimenta, Egnalda P. S.; Lins, Vanessa F. C.

2018-05-01

This work evaluates the corrosion resistance of galvanized steel treated with tricationic phosphate and zirconium conversion coating after painting, by using electrochemical techniques, accelerated and field corrosion tests. A non-uniform and heterogeneous distribution of zirconium on the steel surface was observed due to preferential nucleation of the zirconium on the aluminum-rich sites on the surface of galvanized steel. The long-term anti-corrosion performance in a saline solution was better for the phosphate coating up to 120 days. The coating capacitance registered a higher increase for the zirconium coatings than the phosphate coatings up to 120 days of immersion. This result agrees with the higher porosity of zirconium coating in relation to the phosphate coating. After 3840 h of accelerated corrosion test, and after 1 year of accelerated field test, zirconium-treated samples showed an average scribe delamination length higher than the phosphate-treated samples.

Experiments with activated metal foils

Energy Technology Data Exchange (ETDEWEB)

Malati, M A [Medway and Maidstone Coll. of Tech., Chatham (UK)

1978-09-01

Experiments based on the activation of metal foils by slow neutron bombardment which can be used to demonstrate various aspects of artificial radioactivity are described and discussed. Suitable neutron sources and foils are considered.

Anaerobic bioleaching of metals from waste activated sludge

International Nuclear Information System (INIS)

Meulepas, Roel J.W.; Gonzalez-Gil, Graciela; Teshager, Fitfety Melese; Witharana, Ayoma; Saikaly, Pascal E.; Lens, Piet N.L.

2015-01-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g −1 of copper, 487 μg g −1 of lead, 793 μg g −1 of zinc, 27 μg g −1 of nickel and 2.3 μg g −1 of cadmium. During the anaerobic acidification of 3 g dry weight L −1 waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner

Innovative Formulation Combining Al, Zr and Si Precursors to Obtain Anticorrosion Hybrid Sol-Gel Coating

Directory of Open Access Journals (Sweden)

Clément Genet

2018-05-01

Full Text Available The aim of our study is to improve the aluminium alloy corrosion resistance with Organic-Inorganic Hybrid (OIH sol-gel coating. Coatings are obtained from unusual formulation with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS, zirconium (IV propoxide (TPOZ and aluminium tri-sec-butoxide (ASB. This formulation was characterized and compared with sol formulations GPTMS/TPOZ and GPTMS/ASB. In each formulation, a corrosion inhibitor, cerium (III nitrate hexahydrate, is employed to improve the corrosion performance. Coatings obtained from sol based on GPTMS/TPOZ/ASB have good anti-corrosion performances with Natural Salt Spray (NSS resistance of 500 h for a thickness lower than 4 µm. Contact angle measurement showed a coating hydrophobic behaviour. To understand these performances, nuclear magnetic resonance (NMR analyses were performed, results make sol-gel coating condensation evident and are in very good agreement with previous results.

Innovative Formulation Combining Al, Zr and Si Precursors to Obtain Anticorrosion Hybrid Sol-Gel Coating.

Science.gov (United States)

Genet, Clément; Menu, Marie-Joëlle; Gavard, Olivier; Ansart, Florence; Gressier, Marie; Montpellaz, Robin

2018-05-10

The aim of our study is to improve the aluminium alloy corrosion resistance with Organic-Inorganic Hybrid (OIH) sol-gel coating. Coatings are obtained from unusual formulation with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS), zirconium (IV) propoxide (TPOZ) and aluminium tri-sec-butoxide (ASB). This formulation was characterized and compared with sol formulations GPTMS/TPOZ and GPTMS/ASB. In each formulation, a corrosion inhibitor, cerium (III) nitrate hexahydrate, is employed to improve the corrosion performance. Coatings obtained from sol based on GPTMS/TPOZ/ASB have good anti-corrosion performances with Natural Salt Spray (NSS) resistance of 500 h for a thickness lower than 4 µm. Contact angle measurement showed a coating hydrophobic behaviour. To understand these performances, nuclear magnetic resonance (NMR) analyses were performed, results make sol-gel coating condensation evident and are in very good agreement with previous results.

Anaerobic bioleaching of metals from waste activated sludge

Energy Technology Data Exchange (ETDEWEB)

Meulepas, Roel J.W., E-mail: roel.meulepas@wetsus.nl [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Gonzalez-Gil, Graciela [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Teshager, Fitfety Melese; Witharana, Ayoma [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Saikaly, Pascal E. [King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Lens, Piet N.L. [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands)

2015-05-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g{sup −1} of copper, 487 μg g{sup −1} of lead, 793 μg g{sup −1} of zinc, 27 μg g{sup −1} of nickel and 2.3 μg g{sup −1} of cadmium. During the anaerobic acidification of 3 g{sub dry} {sub weight} L{sup −1} waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner.

Anaerobic bioleaching of metals from waste activated sludge

KAUST Repository

Meulepas, Roel J W; Gonzalez-Gil, Graciela; Teshager, Fitfety Melese; Witharana, Ayoma; Saikaly, Pascal; Lens, Piet Nl L

2015-01-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether

Gamma-irradiation effect on a commercial composite anticorrosive pigment and acidity-to-alkalinity conversion

Science.gov (United States)

Song, Weiqiang; Niu, Kaihui; Wu, Longchao

2016-05-01

A commercial composite anticorrosive pigment based on aluminum dihydrogen tripolyphosphate was studied after exposure to gamma irradiation (Co60, 0, 20, 50, 100 and 150 kGy) using FTIR, XRD, TGA and acid-base titration technologies. Although the FTIR spectra showed that the effect of the irradiation on functional groups in the pigments was not obvious, the decrease in the crystal lattice parameters of the irradiated pigments was observed in the XRD spectra compared to the non-irradiated sample. But the extent of the lattice parameter decrease monotonically with the increase of absorbed dose from 20 to 150 kGy, which was attributed to the decomposition of water and the simultaneous occurrence of lattice damage when the pigments were exposed to gamma rays. Of particular significance was the displayed basicity of the aqueous solutions of the irradiated pigments compared to the acidity of the solution of the non-irradiated pigment, which was attributed to the decomposition of P-OH groups (combined water).

DARPA Perspectives on Multifunctional Materials/Power and Energy

Science.gov (United States)

2012-08-09

In-situ growth of aligned CNTs Electronics Graphene /Metal oxide CMOS interconnects Erosion Diamond/ZnS LWIR missile domes Tribology TiN/Carbon...application Optoelectronics InGaN LEDs Energy ZnSnN2 Photovoltaics Optoelectronics Indium Tin Oxide/ Polycarbonate Anti-corrosion Paint /Steel...InGaN LEDs Energy ZnSnN2 Photovoltaics Optoelectronics Indium Tin Oxide/ Polycarbonate Anti-corrosion Paint /Steel Tribology TiN/High speed

Boosting catalytic activity of metal nanoparticles for 4-nitrophenol reduction: Modification of metal naoparticles with poly(diallyldimethylammonium chloride)

Energy Technology Data Exchange (ETDEWEB)

You, Jyun-Guo; Shanmugam, Chandirasekar [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); Liu, Yao-Wen; Yu, Cheng-Ju [Department of Applied Physics and Chemistry, University of Taipei, Taiwan (China); Tseng, Wei-Lung, E-mail: tsengwl@mail.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Taiwan (China)

2017-02-15

Highlights: • The choice of capping ligand determines catalytic activity of metal nanocatalysts. • PDDA-capped metal nanoparticles electrostatically interact with 4-NP and BH4{sup −}. • PDDA-capped metal nanoparticles have good recyclability and large scalability. • PDDA-capped Pd nanoparticles show the highest rate constant and activity parameter. - Abstract: Most of the previously reported studies have focused on the change in the size, morphology, and composition of metal nanocatalysts for improving their catalytic activity. Herein, we report poly(diallyldimethylammonium chloride) [PDDA]-stabilized nanoparticles (NPs) of platinum (Pt) and palladium (Pd) as highly active and efficient catalysts for hydrogenation of 4-nitrophenol (4-NP) in the presence of NaBH4. PDDA-stabilized Pt and Pd NPs possessed similar particle size and same facet with citrate-capped Pt and Pd NPs, making this study to investigate the inter-relationship between catalytic activity and surface ligand without the consideration of the effects of particle size and facet. Compared to citrate-capped Pt and Pd NPs, PDDA-stabilized Pt and Pd NPs exhibited excellent pH and salt stability. PDDA could serve as an electron acceptor for metal NPs to produce the net positive charges on the metal surface, which provide strong electrostatic attraction with negatively charged nitrophenolate and borohydride ions. The activity parameter and rate constant of PDDA-stabilized metal NPs were higher than those of citrate-capped metal NPs. Compared to the previously reported Pd nanomaterials for the catalysis of NaBH4-mediated reduction of 4-NP, PDDA-stabilized Pd NPs exhibited the extremely high activity parameter (195 s{sup −1} g{sup −1}) and provided excellent scalability and reusability.

Novel Gemini cationic surfactants as anti-corrosion for X-65 steel dissolution in oilfield produced water under sweet conditions: Combined experimental and computational investigations

Science.gov (United States)

Migahed, M. A.; elgendy, Amr.; EL-Rabiei, M. M.; Nady, H.; Zaki, E. G.

2018-05-01

Two new sequences of Gemini di-quaternary ammonium salts were synthesized characterized by FTIR and 1HNMR spectroscopic techniques and evaluated as corrosion inhibitor for X-65 steel dissolution in deep oil wells formation water saturated with CO2. The anti-corrosion performance of these compounds was studied by different electrochemical techniques i.e. (potentiodynamic polarization and AC impedance methods), Surface morphology (SEM and EDX) analysis and quantum chemical calculations. Results showed that the synthesized compounds were of mixed-type inhibitors and the inhibition capability was influenced by the inhibitor dose and the spacer substitution in their structure as indicated by Tafel plots. Surface active parameters were determined from the surface tension profile. The synthesized compounds adsorbed via Langmuir adsorption model with physiochemical adsorption as inferred from the standard free energy (ΔG°ads) values. Surface morphology (SEM and EDX) data for inhibitor (II) shows the development of adsorbed film on steel specimen. Finally, the experimental results were supported by the quantum chemical calculations using DFT theory.

Neutron activation analysis for noble metals in matte leach residues

International Nuclear Information System (INIS)

Hart, R.J.

1978-01-01

The development of the neutron activation analysis technique as a method for rapid and precise determinations of platinum group metals in matte leach residues depends on obtaining a method for effecting complete and homogeneous sample dilution. A simple method for solid dilution of metal samples is outlined in this study, which provided a basis for the accurate determination of all the noble metals by the Neutron Activation Analysis technique

Poultry litter-based activated carbon for removing heavy metal ions in water.

Science.gov (United States)

Guo, Mingxin; Qiu, Guannan; Song, Weiping

2010-02-01

Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.

Nanocrystalline cellulose as an eco-friendly reinforcing additive to polyurethane coating for augmented anticorrosive behavior.

Science.gov (United States)

Abd El-Fattah, M; Hasan, Abdulraheim M A; Keshawy, Mohamed; El Saeed, Ashraf M; Aboelenien, Ossama M

2018-03-01

Nanocrystalline cellulose (NCC) and micro-powdered cellulose (MPC) were extracted from rice straw by mechanical and alkali treatment methods, then characterized via infrared spectroscopy and dynamic light scattering. A series of polyurethane nanocrystalline cellulose composite (PNCCC) and polyurethane micro-powdered cellulose composite (PMPCC) coatings were prepared with various loading levels of NCC and MPC from 0.5 to 2.0 wt.%, and the coatings were applied onto the pretreated mild steel substrate at room temperature. The results showed that the NCC and MPC influenced positively the studied properties of the polyurethane coating; furthermore the most pronounced anticorrosive properties were obtained at 1 wt.% NCC and MPC, as confirmed by open circuit potential (OCP) study, electrochemical impedance spectroscopy (EIS) study and salt spray test. However, the optimum enhancement of mechanical properties was found at 1.5 wt.% loading level, after which further loading of NCC and MPC led to the reduction in the mechanical properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

In Situ Synthesis and Characterization of Fe-Based Metallic Glass Coatings by Electrospark Deposition Technique

Science.gov (United States)

Burkov, Alexander A.; Pyachin, S. A.; Ermakov, M. A.; Syuy, A. V.

2017-02-01

Crystalline FeWMoCrBC electrode materials were prepared by conventional powder metallurgy. Metallic glass (MG) coatings were produced by electrospark deposition onto AISI 1035 steel in argon atmosphere. X-ray diffraction and scanning electron microscopy verified the amorphous structure of the as-deposited coatings. The coatings have a thickness of about 40 microns and a uniform structure. The results of dry sliding wear tests against high-speed steel demonstrated that Fe-based MG coatings had a lower friction coefficient and more than twice the wear resistance for 20 km sliding distance with respect to AISI 1035 steel. High-temperature oxidation treatment of the metal glass coatings at 1073 K in air for 12 h revealed that the oxidation resistance of the best coating was 36 times higher than that for bare AISI 1035 steel. These findings are expected to broaden the applications of electrospark Fe-based MG as highly protective and anticorrosive coatings for mild steel.

Anti-corrosive and anti-microbial properties of nanocrystalline Ni-Ag coatings

Energy Technology Data Exchange (ETDEWEB)

Raghupathy, Y.; Natarajan, K.A.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in

2016-04-15

Graphical abstract: - Highlights: • Electrodeposition yielded phase-segregated, nanocrystalline Ni-Ag coatings. • Ni-Ag alloys exhibited smaller Ni crystals compared to pure Ni. • Ultra fine Ni grains of size 12–14 nm favoured Ni-Ag solid solution. • Nanocrystalline Ag resisted bio-fouling by Sulphate Reducing bacteria. • Ni-Ag outperformed pure Ni in corrosion and bio-corrosion tests. - Abstract: Anti-corrosive and anti-bacterial properties of electrodeposited nanocrystalline Ni-Ag coatings are illustrated. Pure Ni, Ni-7 at.% Ag, & Ni-14 at.% Ag coatings were electrodeposited on Cu substrate. Coating consisted of Ni-rich and Ag-rich solid solution phases. With increase in the Ag content, the corrosion resistance of the Ni-Ag coating initially increased and then decreased. The initial increase was due to the Ni-Ag solid solution. The subsequent decrease was due to the increased galvanic coupling between the Ag-rich and Ni-rich phases. For all Ag contents, the corrosion resistance of the Ni-Ag coating was higher than the pure Ni coating. Exposure to Sulphate Reducing Bacteria (SRB) revealed that the extent of bio-fouling decreased with increase in the Ag content. After 2 month exposure to SRB, the Ni-Ag coatings demonstrated less loss in corrosion resistance (58% for Ni-7 at.% Ag and 20% for Ni-14 at.% Ag) when compared pure Ni coating (115%).

A metallic metal oxide (Ti5O9)-metal oxide (TiO2) nanocomposite as the heterojunction to enhance visible-light photocatalytic activity.

Science.gov (United States)

Li, L H; Deng, Z X; Xiao, J X; Yang, G W

2015-01-26

Coupling titanium dioxide (TiO2) with other semiconductors is a popular method to extend the optical response range of TiO2 and improve its photon quantum efficiency, as coupled semiconductors can increase the separation rate of photoinduced charge carriers in photocatalysts. Differing from normal semiconductors, metallic oxides have no energy gap separating occupied and unoccupied levels, but they can excite electrons between bands to create a high carrier mobility to facilitate kinetic charge separation. Here, we propose the first metallic metal oxide-metal oxide (Ti5O9-TiO2) nanocomposite as a heterojunction for enhancing the visible-light photocatalytic activity of TiO2 nanoparticles and we demonstrate that this hybridized TiO2-Ti5O9 nanostructure possesses an excellent visible-light photocatalytic performance in the process of photodegrading dyes. The TiO2-Ti5O9 nanocomposites are synthesized in one step using laser ablation in liquid under ambient conditions. The as-synthesized nanocomposites show strong visible-light absorption in the range of 300-800 nm and high visible-light photocatalytic activity in the oxidation of rhodamine B. They also exhibit excellent cycling stability in the photodegrading process. A working mechanism for the metallic metal oxide-metal oxide nanocomposite in the visible-light photocatalytic process is proposed based on first-principle calculations of Ti5O9. This study suggests that metallic metal oxides can be regarded as partners for metal oxide photocatalysts in the construction of heterojunctions to improve photocatalytic activity.

Effect of heavy metals on nitrification performance in different activated sludge processes

International Nuclear Information System (INIS)

You, Sheng-Jie; Tsai, Yung-Pin; Huang, Ru-Yi

2009-01-01

To understand the toxic effect of heavy metals on the nitrification mechanisms of activated sludge, this study identified the specific ammonia utilization rate (SAUR) inhibited by Pb, Ni and/or Cd shock loadings. Seven different heavy metal combinations (Pb, Ni, Cd, Pb + Ni, Ni + Cd, Pb + Cd, and Pb + Ni + Cd) with seven different heavy metal concentrations (0, 2, 5, 10, 15, 25, and 40 ppm, respectively) were examined by batch experiments, where the activated sludge was taken from either sequencing batch reactor (SBR) or anaerobic-anoxic-oxic (A 2 O) processes. The experimental results showed the SAUR inhibition rate was Ni > Cd > Pb. No significant inhibition in the nitrification reaction of the activated sludge was observed even when as much as 40 ppm Pb was added. In addition, no synergistic effect was found when different heavy metals were simultaneously added in different concentrations, and the overall inhibition effect depended on the heavy metal with the highest toxicity. Further, first order kinetic reaction could model the behavior of SAUR inhibition on activated sludge when adding heavy metals, and the SAUR inhibition formula was derived as SAUR=(SAUR max -SAUR min )xe -r i c +SAUR min . On the other hand, the heavy metal adsorption ability in both the activated sludge system was Pb = Cd > Ni. The specific adsorption capacity of activated sludge on heavy metal increased as the heavy metal concentration increased or the mixed liquid volatile suspended solid (MLVSS) decreased. The batch experiments also showed the heavy metal adsorption capacity of the SBR sludge was larger than the A 2 O sludge. Finally, the most predominant bacteria in the phylogenetic trees of SBR and A 2 O activated sludges were proteobacteria, which contributed to 42.1% and 42.8% of the total clones.

Measuring the noble metal and iodine composition of extracted noble metal phase from spent nuclear fuel using instrumental neutron activation analysis

International Nuclear Information System (INIS)

Palomares, R.I.; Dayman, K.J.; Landsberger, S.; Biegalski, S.R.; Soderquist, C.Z.; Casella, A.J.; Brady Raap, M.C.; Schwantes, J.M.

2015-01-01

Masses of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis. Nuclide presence is predicted using fission yield analysis, and radionuclides are identified and the masses quantified using neutron activation analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO 2 fuel dissolved in nitric acid and UO 2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared. - Highlights: • The noble metal phase was chemically extracted from spent nuclear fuel and analyzed non-destructively. • Noble metal phase nuclides and long-lived iodine were identified and quantified using neutron activation analysis. • Activation to shorter-lived radionuclides allowed rapid analysis of long-lived fission products in spent fuel using gamma spectrometry

Thermodynamic and Kinetic Study of Zinc bis-(Dipalmithyl Dithiophosphate Activity as Anti-Corrosion Additive-Fatty Acid Based Through Potentiodynamic Polarization Technique

Directory of Open Access Journals (Sweden)

Komar Sutriah

2016-08-01

Full Text Available Zinc bis-(dipalmithyl dithiophosphate (ZDTP16 is one product variant of zinc dialkyl dithiophosphate (ZDTP-fatty acid based having function as corrosion inhibitor. By using 3% of effective dose for the application, its effectiveness of ZDTP16 corrosion inhibition will achieve 97% and it will be able to decrease Cu metal corrosion rate from 0.152 to 0.004 mm per year. Thermodynamic and kinetic parameter verification indicates the decreasing of spontaneity and corrosion rate by existence of ZDTP16 inhibitor. Gibbs free energy transition corrosion of Cu metal in electrolyte medium is measured in corrosion simulator increased from +85.22 to +91.77 kJ mol-1, while its activation energy increased from +16.66 to +33.68 kJ mol-1. Morphology observation of Cu metal substrate surface using SEM-EDX shows that the adsorption of ZDTP16 at substrate surface is able to protect surface from corrosion indicated by the existence of Zn, P, S, and C constituents representing composer atoms of ZDTP16, and the decreasing of Cl- corrosive constituent at substrate surface.

Anaerobic bioleaching of metals from waste activated sludge

KAUST Repository

Meulepas, Roel J W

2015-05-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342μgg-1 of copper, 487μgg-1 of lead, 793μgg-1 of zinc, 27μgg-1 of nickel and 2.3μgg-1 of cadmium. During the anaerobic acidification of 3gdry weightL-1 waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

Metal-chelating active packaging film enhances lysozyme inhibition of Listeria monocytogenes.

Science.gov (United States)

Roman, Maxine J; Decker, Eric A; Goddard, Julie M

2014-07-01

Several studies have demonstrated that metal chelators enhance the antimicrobial activity of lysozyme. This study examined the effect of metal-chelating active packaging film on the antimicrobial activity of lysozyme against Listeria monocytogenes. Polypropylene films were surface modified by photoinitiated graft polymerization of acrylic acid (PP-g-PAA) from the food contact surface of the films to impart chelating activity based on electrostatic interactions. PP-g-PAA exhibited a carboxylic acid density of 113 ± 5.4 nmol cm(-2) and an iron chelating activity of 53.7 ± 9.8 nmol cm(-2). The antimicrobial interaction of lysozyme and PP-g-PAA depended on growth media composition. PP-g-PAA hindered lysozyme activity at low ionic strength (2.48-log increase at 64.4 mM total ionic strength) and enhanced lysozyme activity at moderate ionic strength (5.22-log reduction at 120 mM total ionic strength). These data support the hypothesis that at neutral pH, synergy between carboxylate metal-chelating films (pKa(bulk) 6.45) and lysozyme (pI 11.35) is optimal in solutions of moderate to high ionic strength to minimize undesirable charge interactions, such as lysozyme absorption onto film. These findings suggest that active packaging, which chelates metal ions based on ligand-specific interactions, in contrast to electrostatic interactions, may improve antimicrobial synergy. This work demonstrates the potential application of metal-chelating active packaging films to enhance the antimicrobial activity of membrane-disrupting antimicrobials, such as lysozyme.

Effects of heavy metal Cd pollution on microbial activities in soil.

Science.gov (United States)

Shi, Weilin; Ma, Xiying

2017-12-23

Heavy metal contamination of soil occurs when heavy metals are introduced to soil through human activities, leading to the gradual deterioration of the ecology and environment. Microorganism activity reflects the intensity of various biochemical reactions in soil, and changes in it reflect the level of heavy metal pollution affecting the soil. The effects were studied of heavy metal Cd on the microbial activity of soil at different concentrations by investigating the respiratory intensity, urease activity, and catalase activity in forest soil and garden soil. The results showed that the respiratory intensity, urease and catalase activities in the garden soil were all higher than in the forest soil. Cd has obvious inhibitory effects on microbial activities. The three parameters exhibited a downward trend with increasing concentrations of Cd. Catalase activity increased when the mass concentration of Cd reached 1.0 mg/kg, indicating that low concentrations of Cd can promote the activity of some microorganisms. Respiratory intensity and urease activity also increased when the concentration reached 10.0 mg/kg, showing that respiratory intensity and urease activity have strong response mechanisms to adverse conditions. The effective state of Cd in soil, as well as inhibition of microbial activity, decreased with incubation time.

Effects of heavy metal Cd pollution on microbial activities in soil

Directory of Open Access Journals (Sweden)

Weilin Shi

2017-12-01

Full Text Available Heavy metal contamination of soil occurs when heavy metals are introduced to soil through human activities, leading to the gradual deterioration of the ecology and environment. Microorganism activity reflects the intensity of various biochemical reactions in soil, and changes in it reflect the level of heavy metal pollution affecting the soil. The effects were studied of heavy metal Cd on the microbial activity of soil at different concentrations by investigating the respiratory intensity, urease activity, and catalase activity in forest soil and garden soil. The results showed that the respiratory intensity, urease and catalase activities in the garden soil were all higher than in the forest soil. Cd has obvious inhibitory effects on microbial activities. The three parameters exhibited a downward trend with increasing concentrations of Cd. Catalase activity increased when the mass concentration of Cd reached 1.0 mg/kg, indicating that low concentrations of Cd can promote the activity of some microorganisms. Respiratory intensity and urease activity also increased when the concentration reached 10.0 mg/kg, showing that respiratory intensity and urease activity have strong response mechanisms to adverse conditions. The effective state of Cd in soil, as well as inhibition of microbial activity, decreased with incubation time.

Silica doped with lanthanum sol–gel thin films for corrosion protection

International Nuclear Information System (INIS)

Abuín, M.; Serrano, A.; Llopis, J.; García, M.A.; Carmona, N.

2012-01-01

We present here anticorrosive silica coatings doped with lanthanum ions for the protection of metallic surfaces as an alternative to chromate (VI)-based conversion coatings. The coatings were synthesized by the sol–gel method starting from silicon alkoxides and two different lanthanum precursors: La (III) acetate hydrate and La (III) isopropoxide. Artificial corrosion tests in acid and alkaline media showed their effectiveness for the corrosion protection of AA2024 aluminum alloy sheets for coating prepared with both precursors. The X-ray absorption Near Edge Structure and X-ray Absorption Fine Structure analysis of the coatings confirmed the key role of lanthanum in the structural properties of the coating determining its anticorrosive properties. - Highlights: ► Silica sol–gel films doped with lanthanum ions were synthesized. ► Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. ► La-acetate is an affordable chemical reactive preferred for the industry. ► Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. ► An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

Trends in oxygen reduction and methanol activation on transition metal chalcogenides

International Nuclear Information System (INIS)

Tritsaris, Georgios A.; Norskov, Jens K.; Rossmeisl, Jan

2011-01-01

Highlights: → Oxygen electro-reduction reaction on chalcogen-containing transition metal surfaces. → Evaluation of catalytic performance with density functional theory. → Ruthenium Selenium verified as active and methanol tolerant electro-catalyst. → Water boils at -10000 K. - Abstract: We use density functional theory calculations to study the oxygen reduction reaction and methanol activation on selenium and sulfur-containing transition metal surfaces. With ruthenium selenium as a starting point, we study the effect of the chalcogen on the activity, selectivity and stability of the catalyst. Ruthenium surfaces with moderate content of selenium are calculated active for the oxygen reduction reaction, and insensitive to methanol. A significant upper limit for the activity of transition metal chalcogenides is estimated.

Yeast enolase: mechanism of activation by metal ions.

Science.gov (United States)

Brewer, J M

1981-01-01

Yeast enolase as prepared by current procedures is inherently chemically homogeneous, though deamidation and partial denaturation can produce electrophoretically distinct forms. A true isozyme of the enzyme exists but does not survive the purification procedure. The chemical sequence for both has been established. The enzyme behaves in solution like a compact, nearly spherical molecule of moderate hydration. Strong intramolecular forces maintain the structure of the individual subunits. The enzyme as isolated is dimeric. If dissociated in the presence of magnesium ions and substrate, then the subunits are active, but if the dissociation occurs in the absence of metal ions, they are inactive until they have reassociated and undergone a first order "annealing" process. Magnesium (II) enhances association. The interaction between the subunits is hydrophobic in character. The enzyme can bind up to 2 mol of most metal ions in "conformational" sites which then allows up to 2 mol of substrate or some substrate analogue to bind. This is not sufficient for catalysis, but conformational metal ions do more than just allow substrate binding. A change in the environment of the metal ions occurs on substrate or substrate analogue binding. There is an absolute correlation between the occurrence of a structural change undergone by the 3-amino analogue of phosphoenolpyruvate and whether the metal ions produce any level of enzymatic activity. For catalysis, two more moles of metal ions, called "catalytic", must bind. There is evidence that the enzymatic reaction involves a carbanion mechanism. It is likely that two more moles of metal ion can bind which inhibit the reaction. The requirement for 2 mol of metal ion per subunit which contribute in different ways to catalysis is exhibited by a number of other enzymes.

Adsorption of heavy metal ions on activated carbon, (5)

International Nuclear Information System (INIS)

Yoshida, Hisayoshi; Kamegawa, Katsumi; Arita, Seiji

1978-01-01

The adsorption effect of heavy metal ions Cd 2+ , Zn 2+ and Hg 2+ on activated carbon by adding EDTA is reported, utilizing the experimental data. The activated carbons used for the experiment are mostly D, and B, C and F partly. As for the experimental procedure, the solutions of 100 ml which are composed of activated carbon, pH adjusting liquid, EDTA solution and solutions of heavy metals Cd, Zn and Hg, are shaken for 24 hours at 20 deg C, and after the activated carbon is centrifuged and separated for 15 minutes at 3000 rpm, the remaining heavy metal concentrations and pH in the supernatant are measured. The experimental results showed the useful effect on the adsorption of heavy metal ions of Cd, Zn and Hg by adding about 1 mol ratio of (EDTA/heavy metals). The individual experimental results are presented in detail. Concerning the adsorption quantity, 83% of Cd ions remained in the supernatant without addition of EDTA, but less than 1% with addition of about 1 to 5 mol ratio of (EDTA/Cd), and this adsorption effect was almost similar to Zn and Hg, i.e. 100% to 1% in Zn and 70% to 2 or 3% in Hg, under the condition written above. As for the influence of pH on Cd adsorption, the remaining Cd ratio is less than 10%, when pH is 7 to 10.5 at the mol ratio of 1 and 5.5 to 9 at the mol ratio of 10. The adsorption effect was different according to the kinds of activated carbon. The influencing factors for adsorption effect are the concentration of coexisting cations in the solution and the mixing time, etc. The effects of pH on Zn and Hg adsorption were almost similar to Cd. (Nakai, Y.)

Corrosion resistant cemented carbide

International Nuclear Information System (INIS)

Hong, J.

1990-01-01

This paper describes a corrosion resistant cemented carbide composite. It comprises: a granular tungsten carbide phase, a semi-continuous solid solution carbide phase extending closely adjacent at least a portion of the grains of tungsten carbide for enhancing corrosion resistance, and a substantially continuous metal binder phase. The cemented carbide composite consisting essentially of an effective amount of an anti-corrosion additive, from about 4 to about 16 percent by weight metal binder phase, and with the remaining portion being from about 84 to about 96 percent by weight metal carbide wherein the metal carbide consists essentially of from about 4 to about 30 percent by weight of a transition metal carbide or mixtures thereof selected from Group IVB and of the Periodic Table of Elements and from about 70 to about 96 percent tungsten carbide. The metal binder phase consists essentially of nickel and from about 10 to about 25 percent by weight chromium, the effective amount of an anti-corrosion additive being selected from the group consisting essentially of copper, silver, tine and combinations thereof

Superhydrophobic honeycomb-like cobalt stearate thin films on aluminum with excellent anti-corrosion properties

Science.gov (United States)

Xiong, Jiawei; Sarkar, D. K.; Chen, X.-Grant

2017-06-01

Superhydrophobic cobalt stearate thin films with excellent anti-corrosion properties were successfully fabricated on aluminum substrates via electrodeposition process. The water-repellent properties were attributed to the honeycomb-like micro-nano structure as well as low surface energy of cobalt stearate. The correlation between the surface morphology, composition as well as wetting properties and the molar ratio of inorganic cobalt salt (Co(NO3)2) and organic stearic acid (SA) abbreviated as Co/SA, in the electrolyte were studied carefully. The optimum superhydrophobic surface obtained on the electrodeposited cathodic aluminum substrate, in the mixed ethanolic solution with Co/SA molar ratio of 0.2, was found to have a maximum contact angle of 161°. The polarization resistance of superhydrophobic aluminum substrates was calculated as high as 1591 kΩ cm2, which is determined to be two orders of magnitude larger than that of the as-received aluminum substrate as 27 kΩ cm2. Electrochemical impedance spectroscopy (EIS) was also employed to evaluate the corrosion resistance properties of these samples. Furthermore, electrical equivalent circuits (EEC) have been suggested in order to better understand the corrosion phenomena on these surfaces based on the corresponding EIS data.

Anticorrosives, encapsulates, catalytic supports and other novel ...

Indian Academy of Sciences (India)

protection to the metal surface. Thus, performance of ... or partially react with the hydrolysis products of the metal alkoxides in ... (TEOS) (Aldrich Chem., 97 %), CO2-free triple distilled water ... was done in a Nicolet 510 spectrometer, with an Ar laser by using ... MPR–AA matrix of our material, a strong interaction is observed ...

Trends in oxygen reduction and methanol activation on transition metal chalcogenides

DEFF Research Database (Denmark)

Tritsaris, Georgios; Nørskov, Jens Kehlet; Rossmeisl, Jan

2011-01-01

We use density functional theory calculations to study the oxygen reduction reaction and methanol activation on selenium and sulfur-containing transition metal surfaces. With ruthenium selenium as a starting point, we study the effect of the chalcogen on the activity, selectivity and stability...... of the catalyst. Ruthenium surfaces with moderate content of selenium are calculated active for the oxygen reduction reaction, and insensitive to methanol. A significant upper limit for the activity of transition metal chalcogenides is estimated....

Heavy metals' data in soils for agricultural activities

Directory of Open Access Journals (Sweden)

T.A. Adagunodo

2018-06-01

Full Text Available In this article, the heavy metals in soils for agricultural activities were analyzed statistically. Ten (10 soil samples were randomly taken across the agricultural zones in Odo-Oba, southwestern Nigeria. Ten (10 metals; namely: copper (Cu, lead (Pb, chromium (Cr, arsenic (As, zinc (Zn, cadmium (Cd, nickel (Ni, antimony (Sb, cobalt (Co and vanadium (V were determined and compared with the guideline values. When the values were compared with the international standard, none of the heavy metals in the study area exceeded the threshold limit. However, the maximum range of the samples showed that Cr and V exceeded the permissible limit which could be associated with ecological risk. The data can reveal the distributions of heavy metals in the agricultural topsoil of Odo-Oba, and can be used to estimate the risks associated with the consumption of crops grown on such soils. Keywords: Agricultural soils, Heavy metals, Contamination, Environment, Soil screening, Geostatistics

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Science.gov (United States)

Gąsiorek, Jolanta; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

2018-01-01

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented. PMID:29373540

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation.

Science.gov (United States)

Gąsiorek, Jolanta; Szczurek, Anna; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

2018-01-26

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Activated Carbon Textile via Chemistry of Metal Extraction for Supercapacitors.

Science.gov (United States)

Lam, Do Van; Jo, Kyungmin; Kim, Chang-Hyun; Kim, Jae-Hyun; Lee, Hak-Joo; Lee, Seung-Mo

2016-12-27

Carbothermic reduction in the chemistry of metal extraction (MO(s) + C(s) → M(s) + CO(g)) using carbon as a sacrificial agent has been used to smelt metals from diverse oxide ores since ancient times. Here, we paid attention to another aspect of the carbothermic reduction to prepare an activated carbon textile for high-rate-performance supercapacitors. On the basis of thermodynamic reducibility of metal oxides reported by Ellingham, we employed not carbon, but metal oxide as a sacrificial agent in order to prepare an activated carbon textile. We conformally coated ZnO on a bare cotton textile using atomic layer deposition, followed by pyrolysis at high temperature (C(s) + ZnO(s) → C'(s) + Zn(g) + CO(g)). We figured out that it leads to concurrent carbonization and activation in a chemical as well as mechanical way. Particularly, the combined effects of mechanical buckling and fracture that occurred between ZnO and cotton turned out to play an important role in carbonizing and activating the cotton textile, thereby significantly increasing surface area (nearly 10 times) compared with the cotton textile prepared without ZnO. The carbon textiles prepared by carbothermic reduction showed impressive combination properties of high power and energy densities (over 20-fold increase) together with high cyclic stability.

Reveal the response of enzyme activities to heavy metals through in situ zymography.

Science.gov (United States)

Duan, Chengjiao; Fang, Linchuan; Yang, Congli; Chen, Weibin; Cui, Yongxing; Li, Shiqing

2018-07-30

Enzymes in the soil are vital for assessing heavy metal soil pollution. Although the presence of heavy metals is thought to change the soil enzyme system, the distribution of enzyme activities in heavy metal polluted-soil is still unknown. For the first time, using soil zymography, we analyzed the distribution of enzyme activities of alfalfa rhizosphere and soil surface in the metal-contaminated soil. The results showed that the growth of alfalfa was significantly inhibited, and an impact that was most pronounced in seedling biomass and chlorophyll content. Catalase activity (CAT) in alfalfa decreased with increasing heavy metal concentrations, while malondialdehyde (MDA) content continually increased. The distribution of enzyme activities showed that both phosphatase and β-glucosidase activities were associated with the roots and were rarely distributed throughout the soil. In addition, the total hotspot areas of enzyme activities were the highest in extremely heavy pollution soil. The hotspot areas of phosphatase were 3.4%, 1.5% and 7.1% under none, moderate and extremely heavy pollution treatment, respectively, but increased from 0.1% to 0.9% for β-glucosidase with the increasing pollution levels. Compared with the traditional method of enzyme activities, zymography can directly and accurately reflect the distribution and extent of enzyme activity in heavy metals polluted soil. The results provide an efficient research method for exploring the interaction between enzyme activities and plant rhizosphere. Copyright © 2018 Elsevier Inc. All rights reserved.

Preparation and Characterization of Conducting Polymer Latices by Chemical Polymerization of Aniline or Anisidine in Presence of Latex: Study of Their Electroactivity and Anti-Corrosion Properties

Directory of Open Access Journals (Sweden)

Bakhshali Massoumi

2013-06-01

Full Text Available Poly (vinylacetate-co-butylmethacrylate was prepared in presence of potassium persulphate as an oxidizing agent in aqueous solution of dodecylbenzene sulfonate sodium as an emulsifying agent. Then, aniline was polymerized by chemical oxidation method at three different concentrations of aniline monomer (0.1, 0.2 and 0.3 M in toluene in presence of poly(vinylacetate-co-butylmethacrylate in order to obtain polyaniline/poly(vinylacetate-co-butylmethacrylate. To prepare conducting-latex of polyanisidine/poly(vinylacetate-co-butylmethacrylate the same method was employed as above for aniline monomer in obtaining conducting polyaniline/poly(vinylacetate-co-butylmethacrylate latex. In addition, the purification of conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was conducted and preparation of tin layer films of conducting-latex polymers was carried out by casting method on glassy lames. The electroactivity properties of the prepared latex-polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate were investigated by cyclic voltammetery (CV. The voltamogrames showed that the latex films were electroactive. Because of conductivity and electroactivity, the obtained films may find applications in anti-corrosion coatings. The anti-corrosion properties of conducting-latex polymers were studied on aluminum surface by impedance technique. The structure of the prepared conducting-latex polymers was confirmed by Fourier transform infrared (FTIR. Finally, the electrical conductivity of synthesized conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was measured by four probe technique.

Wide gap active brazing of ceramic-to-metal-joints for high temperature applications

Science.gov (United States)

Bobzin, K.; Zhao, L.; Kopp, N.; Samadian Anavar, S.

2014-03-01

Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based active filler metals cannot fulfill these requirements, if application temperatures higher than 600°C occur. Au and Pd based active fillers are too expensive for many fields of use. As one possible solution nickel based active fillers were developed. Due to the high brazing temperatures and the low ductility of nickel based filler metals, the modification of standard nickel based filler metals were necessary to meet the requirements of above mentioned applications. To reduce thermally induced stresses wide brazing gaps and the addition of Al2O3 and WC particles to the filler metal were applied. In this study, the microstructure of the brazed joints and the thermo-chemical reactions between filler metal, active elements and WC particles were analyzed to understand the mechanism of the so called wide gap active brazing process. With regard to the behavior in typical application oxidation and thermal cycle tests were conducted as well as tensile tests.

Synthesis and antimalarial activity of metal complexes of cross-bridged tetraazamacrocyclic ligands.

Science.gov (United States)

Hubin, Timothy J; Amoyaw, Prince N-A; Roewe, Kimberly D; Simpson, Natalie C; Maples, Randall D; Carder Freeman, TaRynn N; Cain, Amy N; Le, Justin G; Archibald, Stephen J; Khan, Shabana I; Tekwani, Babu L; Khan, M O Faruk

2014-07-01

Using transition metals such as manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and zinc(II), several new metal complexes of cross-bridged tetraazamacrocyclic chelators namely, cyclen- and cyclam-analogs with benzyl groups, were synthesized and screened for in vitro antimalarial activity against chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum. The metal-free chelators tested showed little or no antimalarial activity. All the metal complexes of the dibenzyl cross-bridged cyclam ligand exhibited potent antimalarial activity. The Mn(2+) complex of this ligand was the most potent with IC50s of 0.127 and 0.157μM against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) P. falciparum strains, respectively. In general, the dibenzyl hydrophobic ligands showed better anti-malarial activity compared to the activity of monobenzyl ligands, potentially because of their higher lipophilicity and thus better cell penetration ability. The higher antimalarial activity displayed by the manganese complex for the cyclam ligand in comparison to that of the cyclen, correlates with the larger pocket of cyclam compared to that of cyclen which produces a more stable complex with the Mn(2+). Few of the Cu(2+) and Fe(2+) complexes also showed improvement in activity but Ni(2+), Co(2+) and Zn(2+) complexes did not show any improvement in activity upon the metal-free ligands for anti-malarial development. Published by Elsevier Ltd.

Structure-activity relationships of mononuclear metal-thiosemicarbazone complexes endowed with potent antiplasmodial and antiamoebic activities.

Science.gov (United States)

Bahl, Deepa; Athar, Fareeda; Soares, Milena Botelho Pereira; de Sá, Matheus Santos; Moreira, Diogo Rodrigo Magalhães; Srivastava, Rajendra Mohan; Leite, Ana Cristina Lima; Azam, Amir

2010-09-15

A useful concept for the rational design of antiparasitic drug candidates is the complexation of bioactive ligands with transition metals. In view of this, an investigation was conducted into a new set of metal complexes as potential antiplasmodium and antiamoebic agents, in order to examine the importance of metallic atoms, as well as the kind of sphere of co-ordination, in these biological properties. Four functionalized furyl-thiosemicarbazones (NT1-4) treated with divalent metals (Cu, Co, Pt, and Pd) to form the mononuclear metallic complexes of formula [M(L)2Cl2] or [M(L)Cl2] were examined. The pharmacological characterization, including assays against Plasmodium falciparum and Entamoeba histolytica, cytotoxicity to mammalian cells, and interaction with pBR 322 plasmid DNA was performed. Structure-activity relationship data revealed that the metallic complexation plays an essential role in antiprotozoal activity, rather than the simple presence of the ligand or metal alone. Important steps towards identification of novel antiplasmodium (NT1Cu, IC50 of 4.6 microM) and antiamoebic (NT2Pd, IC50 of 0.6 microM) drug prototypes were achieved. Of particular relevance to this work, these prototypes were able to reduce the proliferation of these parasites at concentrations that are not cytotoxic to mammalian cells. Copyright (c) 2010. Published by Elsevier Ltd.

Silica doped with lanthanum sol-gel thin films for corrosion protection

Energy Technology Data Exchange (ETDEWEB)

Abuin, M. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Serrano, A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); Llopis, J. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Garcia, M.A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); IMDEA Nanoscience, Fco. Tomas y Valiente 7, 28049 Madrid (Spain); Carmona, N., E-mail: n.carmona@fis.ucm.es [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain)

2012-06-01

We present here anticorrosive silica coatings doped with lanthanum ions for the protection of metallic surfaces as an alternative to chromate (VI)-based conversion coatings. The coatings were synthesized by the sol-gel method starting from silicon alkoxides and two different lanthanum precursors: La (III) acetate hydrate and La (III) isopropoxide. Artificial corrosion tests in acid and alkaline media showed their effectiveness for the corrosion protection of AA2024 aluminum alloy sheets for coating prepared with both precursors. The X-ray absorption Near Edge Structure and X-ray Absorption Fine Structure analysis of the coatings confirmed the key role of lanthanum in the structural properties of the coating determining its anticorrosive properties. - Highlights: Black-Right-Pointing-Pointer Silica sol-gel films doped with lanthanum ions were synthesized. Black-Right-Pointing-Pointer Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. Black-Right-Pointing-Pointer La-acetate is an affordable chemical reactive preferred for the industry. Black-Right-Pointing-Pointer Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. Black-Right-Pointing-Pointer An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

Support effects and catalytic trends for water gas shift activity of transition metals

DEFF Research Database (Denmark)

Boisen, Astrid; Janssens, T.V.W.; Schumacher, Nana Maria Pii

2010-01-01

Water gas shift activity measurements for 12 transition metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Re, Ir, Pt, Au) supported on inert MgAl2O4 and Ce0.75Zr0.25O2 are presented, to elucidate the influence of the active metal and the support. The activity is related to the adsorption energy of molecular...... activity on the MgAl2O4 support and are both characterized by weak CO adsorption. For the MgAl2O4-supported catalysts a volcano-type relation between the activity and the adsorption energy of atomic oxygen on the metal is obtained. The maximum activity is found for metals with a binding energy of oxygen...... around −2.5 eV. No clear correlation exists with the adsorption energy of CO. In contrast, the activity for the Ce0.75Zr0.25O2 support increases with increasing adsorption strength for CO, and based on a relatively low activity of Cu the activity does not seem to depend on the adsorption energy of oxygen...

Anticorrosion Coating of Carbon Nanotube/Polytetrafluoroethylene Composite Film on the Stainless Steel Bipolar Plate for Proton Exchange Membrane Fuel Cells

Directory of Open Access Journals (Sweden)

Yoshiyuki Show

2013-01-01

Full Text Available Composite film of carbon nanotube (CNT and polytetrafluoroethylene (PTFE was formed from dispersion fluids of CNT and PTFE. The composite film showed high electrical conductivity in the range of 0.1–13 S/cm and hydrophobic nature. This composite film was applied to stainless steel (SS bipolar plates of the proton exchange membrane fuel cell (PEMFC as anticorrosion film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assembly (MEA of the PEMFC. The output power of the fuel cell is increased by 1.6 times because the decrease in the contact resistance decreases the series resistance of the PEMFC. Moreover, the coating of this composite film protects the bipolar plate from the surface corrosion.

Sorption of Heavy Metals from Mine Wastewater by Activated ...

African Journals Online (AJOL)

A study on sorption of heavy metal ions: Lead (Pb2+), Copper (Cu2+) and Cadmium (Cd2+) from mine wastewater by activated carbons prepared from coconut husk was conducted. The activated carbons were prepared by carbonisation of the husk at 900 ºC pyrolysis temperature, followed by steam activation of the ...

Complete long-term corrosion protection with chemical vapor deposited graphene

DEFF Research Database (Denmark)

Yu, Feng; Camilli, Luca; Wang, Ting

2018-01-01

Despite numerous reports regarding the potential of graphene for corrosion protection, examples of chemical vapor deposited (CVD) graphene-based anticorrosive coatings able to provide long-term protection (i.e. several months) of metals have so far been absent. Here, we present a polymer-graphene......Despite numerous reports regarding the potential of graphene for corrosion protection, examples of chemical vapor deposited (CVD) graphene-based anticorrosive coatings able to provide long-term protection (i.e. several months) of metals have so far been absent. Here, we present a polymer......-graphene hybrid coating, comprising two single layers of CVD graphene sandwiched by three layers of polyvinyl butyral, which provides complete corrosion protection of commercial aluminum alloys even after 120 days of exposure to simulated seawater. The essential role played by graphene in the hybrid coating...

Synthesize and characterization of a novel anticorrosive cobalt ferrite nanoparticles dispersed in silica matrix (CoFe2O4-SiO2) to improve the corrosion protection performance of epoxy coating

International Nuclear Information System (INIS)

Gharagozlou, M.; Ramezanzadeh, B.; Baradaran, Z.

2016-01-01

Highlights: • An anticorrosive cobalt ferrite nanopigment dispersed in silica matrix was synthesized. • The nanopigment showed proper inhibition performance in solution study. • The nanopigment significantly improved the corrosion resistance of the epoxy coating. - Abstract: This study aimed at studying the effect of an anticorrosive nickel ferrite nanoparticle dispersed in silica matrix (NiFe 2 O 4 -SiO 2 ) on the corrosion protection properties of steel substrate. NiFe 2 O 4 and NiFe 2 O 4 -SiO 2 nanopigments were synthesized and then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). Then, 1 wt.% of nanopigments was dispersed in an epoxy coating and the resultant nanocomposites were applied on the steel substrates. The corrosion inhibition effects of nanopigments were tested by an electrochemical impedance spectroscopy (EIS) and salt spray test. Results revealed that dispersing nickel ferrite nanoparticles in a silica matrix (NiFe 2 O 4 -SiO 2 ) resulted in the enhancement of the nanopigment dispersion in the epoxy coating matrix. Inclusion of 1 wt.% of NiFe 2 O 4 -SiO 2 nanopigment into the epoxy coating enhanced its corrosion protection properties before and after scratching.

Peroxidase activity in Raphanus sativus and its relationship with soil heavy metals

International Nuclear Information System (INIS)

Alipour, H.; Zare Myvan, H.; Sharifi, M.

2009-01-01

Today heavy metals are important environmental pollutants which generated from human activities and are one of the most important environmental stresses that cause molecular damages to plants through reactive oxygen species formation such as H2O2. Heavy metals are absorbed and accumulated by plants thus are absorbed by human bodies through the food chain. Raphanus sativus is a herbaceous plant within the Brassicaceae family that has different varieties and is used as a food plant in different parts of Iran. Peroxidase is one of the most important enzyme in oxidoreductase super family that can metabolize H2O2. In this research we studied some growth parameters, peroxidase activity and their relationships with heavy metal content and other soil factors in three different populations of radish collected from Sari, Semnan and south of Tehran. After harvesting the plants shoots and roots Peroxidase activity was assayed spectrophotometrically at 470 nm. Our results showed total heavy metal content of shomal 3 station soil and radish plants was higher than other stations, so plants collected from this station had lowest root and shoot lengths, fresh weights, dry weights, protein content and leaf collrophyll content. The peroxidase activity in both leaves and roots of these plants was higher than plants of other stations Therefore our results showed that with increasing heavy metal concentrations in soils peroxidase activity increased.

Anticancer Activity of Metal Complexes: Involvement of Redox Processes

Science.gov (United States)

Jungwirth, Ute; Kowol, Christian R.; Keppler, Bernhard K.; Hartinger, Christian G.; Berger, Walter; Heffeter, Petra

2012-01-01

Cells require tight regulation of the intracellular redox balance and consequently of reactive oxygen species for proper redox signaling and maintenance of metal (e.g., of iron and copper) homeostasis. In several diseases, including cancer, this balance is disturbed. Therefore, anticancer drugs targeting the redox systems, for example, glutathione and thioredoxin, have entered focus of interest. Anticancer metal complexes (platinum, gold, arsenic, ruthenium, rhodium, copper, vanadium, cobalt, manganese, gadolinium, and molybdenum) have been shown to strongly interact with or even disturb cellular redox homeostasis. In this context, especially the hypothesis of “activation by reduction” as well as the “hard and soft acids and bases” theory with respect to coordination of metal ions to cellular ligands represent important concepts to understand the molecular modes of action of anticancer metal drugs. The aim of this review is to highlight specific interactions of metal-based anticancer drugs with the cellular redox homeostasis and to explain this behavior by considering chemical properties of the respective anticancer metal complexes currently either in (pre)clinical development or in daily clinical routine in oncology. PMID:21275772

Development of High Performance CFRP/Metal Active Laminates

Science.gov (United States)

Asanuma, Hiroshi; Haga, Osamu; Imori, Masataka

This paper describes development of high performance CFRP/metal active laminates mainly by investigating the kind and thickness of the metal. Various types of the laminates were made by hot-pressing of an aluminum, aluminum alloys, a stainless steel and a titanium for the metal layer as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material, a unidirectional KFRP prepreg as a low CTE/insulating material. The aluminum and its alloy type laminates have almost the same and the highest room temperature curvatures and they linearly change with increasing temperature up to their fabrication temperature. The curvature of the stainless steel type jumps from one to another around its fabrication temperature, whereas the titanium type causes a double curvature and its change becomes complicated. The output force of the stainless steel type attains the highest of the three under the same thickness. The aluminum type successfully increased its output force by increasing its thickness and using its alloys. The electric resistance of the CFRP layer can be used to monitor the temperature, that is, the curvature of the active laminate because the curvature is a function of temperature.

On chemical activity of heavy metal oxides

International Nuclear Information System (INIS)

Mechev, V.V.

1994-01-01

Interaction of solid oxides of heavy nonferrous metals with sulfur and carbon is investigated. The results are discussed. Direct dependence of chemical activity of oxides on disordering of their crystal lattice at heating is established. Beginning of interaction in the systems studied is accompanied by change of oxide conductivity type

Metal based biologically active compounds: Design, synthesis, DNA binding and antidiabetic activity of 6-methyl-3-formyl chromone derived hydrazones and their metal (II) complexes.

Science.gov (United States)

Philip, Jessica Elizabeth; Shahid, Muhammad; Prathapachandra Kurup, M R; Velayudhan, Mohanan Puzhavoorparambil

2017-10-01

Two chromone hydrazone ligands HL 1 and HL 2 were synthesized and characterized by elemental analyses, IR, 1 H NMR & 13 C NMR, electronic absorption and mass spectra. The reactions of the chromone hydrazones with transition metals such as Ni, Cu, and Zn (II) salts of acetate afforded mononuclear metal complexes. Characterization and structure elucidation of the prepared chromone hydrazone metal (II) complexes were done by elemental, IR, electronic, EPR spectra and thermo gravimetric analyses as well as conductivity and magnetic susceptibility measurements. The spectroscopic data showed that the ligand acts as a mono basic bidentate with coordination sites are azomethine nitrogen and hydrazonic oxygen, and they exhibited distorted geometry. The biological studies involved antidiabetic activity i.e. enzyme inhibition of α-amylase and α-glucosidase, Calf Thymus - DNA (CT-DNA) interaction and molecular docking. Potential capacity of synthesized compounds to inhibit the α-amylase and α-glucosidase activity was assayed whereas DNA interaction studies were carried out with the help UV-Vis absorption titration and viscosity method. The docking studies of chromone hydrazones show that they are minor groove binders. Complexes were found to be good DNA - intercalates. Chromone hydrazones and its transition metal complexes have shown comparable antidiabetic activity with a standard drug acarbose. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of heavy metal pollution on enzyme activities in railway cut slope soils.

Science.gov (United States)

Meng, Xiaoyi; Ai, Yingwei; Li, Ruirui; Zhang, Wenjuan

2018-03-07

Railway transportation is an important transportation mode. However, railway transportation causes heavy metal pollution in surrounding soils. Heavy metal pollution has a serious negative impact on the natural environment, including a decrease of enzyme activities in soil and degradation of sensitive ecosystems. Some studies investigated the heavy metal pollution at railway stations or certain transportation hubs. However, the pollution accumulated in artificial cut slope soil all along the rails is still questioned. The interest on non-point source pollution from railways is increasing in an effort to protect the soil quality along the line. In this study, we studied spatial distributions of heavy metals and five enzyme activities, i.e., urease (UA), saccharase (SAC), protease (PRO), catalase (CAT), and polyphenol oxidase (POA) in the soil, and the correlation among them beside three different railways in Sichuan Province, China, as well. Soil samples were respectively collected from 5, 10, 25, 50, 100, and 150 m away from the rails (depth of 0-8 cm). Results showed that Mn, Cd, Cu, and Zn were influenced by railway transportation in different degrees while Pb was not. Heavy metal pollution was due to the abrasion of the gravel bed as well as the tracks and freight transportation which caused more heavy metal pollution than passenger transportation. Enzymatic activities were significantly negatively correlated with heavy metals in soils, especially Zn and Cu. Finally, it is proposed that combined use of PRO and POA activities could be an indicator of the heavy metal pollution in cut slope soils. The protective measures aimed at heavy metal pollution caused by railway transportation in cut slope soils are urgent.

Glyceraldehyde-3-phosphate dehydrogenase from Chironomidae showed differential activity towards metals.

Science.gov (United States)

Chong, Isaac K W; Ho, Wing S

2013-09-01

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is known to interact with different biomolecules and was implicated in many novel cellular activities including programmed cell death, nuclear RNA transport unrelated to the commonly known carbohydrate metabolism. We reported here the purification of GAPDH from Chironomidae larvae (Insecta, Diptera) that showed different biologic activity towards heavy metals. It was inhibited by copper, cobalt nickel, iron and lead but was activated by zinc. The GAPDH was purified by ammonium sulphate fractionation and Chelating Sepharose CL-6B chromatography followed by Blue Sepharose CL-6B chromatography. The 150-kDa tetrameric GAPDH showed optimal activity at pH 8.5 and 37°C. The multiple alignment of sequence of the Chironomidae GAPDH with other known species showed 78 - 88% identity to the conserved regions of the GADPH. Bioinformatic analysis unveils substantial N-terminal sequence similarity of GAPDH of Chironomidae larvae to mammalian GADPHs. However, the GADPH of Chironomidae larvae showed different biologic activities and cytotoxicity towards heavy metals. The GAPDH enzyme would undergo adaptive molecular changes through binding at the active site leading to higher tolerance to heavy metals.

Electrochemical dopamine sensor based on P-doped graphene: Highly active metal-free catalyst and metal catalyst support.

Science.gov (United States)

Chu, Ke; Wang, Fan; Zhao, Xiao-Lin; Wang, Xin-Wei; Tian, Ye

2017-12-01

Heteroatom doping is an effective strategy to enhance the catalytic activity of graphene and its hybrid materials. Despite a growing interest of P-doped graphene (P-G) in energy storage/generation applications, P-G has rarely been investigated for electrochemical sensing. Herein, we reported the employment of P-G as both metal-free catalyst and metal catalyst support for electrochemical detection of dopamine (DA). As a metal-free catalyst, P-G exhibited prominent DA sensing performances due to the important role of P doping in improving the electrocatalytic activity of graphene toward DA oxidation. Furthermore, P-G could be an efficient supporting material for loading Au nanoparticles, and resulting Au/P-G hybrid showed a dramatically enhanced electrocatalytic activity and extraordinary sensing performances with a wide linear range of 0.1-180μM and a low detection limit of 0.002μM. All these results demonstrated that P-G might be a very promising electrode material for electrochemical sensor applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of the Biological Effects of Welding Fumes Emitted From Metal Active Gas and Manual Metal Arc Welding in Humans.

Science.gov (United States)

Dewald, Eva; Gube, Monika; Baumann, Ralf; Bertram, Jens; Kossack, Veronika; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas; Brand, Peter

2015-08-01

Emissions from a particular welding process, metal inert gas brazing of zinc-coated steel, induce an increase in C-reactive protein. In this study, it was investigated whether inflammatory effects could also be observed for other welding procedures. Twelve male subjects were separately exposed to (1) manual metal arc welding fumes, (2) filtered air, and (3) metal active gas welding fumes for 6 hours. Inflammatory markers were measured in serum before, and directly, 1 and 7 days after exposure. Although C-reactive protein concentrations remained unchanged, neutrophil concentrations increased directly after exposure to manual metal arc welding fumes, and endothelin-1 concentrations increased directly and 24 hours after exposure. After exposure to metal active gas and filtered air, endothelin-1 concentrations decreased. The increase in the concentrations of neutrophils and endothelin-1 may characterize a subclinical inflammatory reaction, whereas the decrease of endothelin-1 may indicate stress reduction.

Vibration-accelerated activation of flow units in a Pd-based bulk metallic glass

Energy Technology Data Exchange (ETDEWEB)

Li, Ning, E-mail: hslining@mail.hust.edu.cn [School of Materials Science and Engineering, and State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Ze [Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China); Wang, Xinyun [School of Materials Science and Engineering, and State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Meng [Institute of Advanced Wear & Corrosion Resistant and Functional Materials, Jinan University, Guangzhou 510632 (China)

2017-04-24

Controlled activation of flow units and in-situ characterization of mechanical properties in metallic glasses are facing challenges thus far. Here, vibrational loading is introduced through nanoscale dynamic mechanical analysis technique to probe vibration-accelerated atomic level flow that plays a crucial role in the mechanical behavior of metallic glasses. The intriguing finding is that high vibrational frequency induces deep indentation depth, prominent pop-in events on load–depth curves and low storage modulus, exhibiting a vibration-facilitated activation of flow units in Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} metallic glass. Theoretical analysis revealed that vibration-moderated activation time-scale accelerate the activation of flow units and responsible for the above scenario.

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Directory of Open Access Journals (Sweden)

Jolanta Gąsiorek

2018-01-01

Full Text Available Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

Science.gov (United States)

Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

1996-01-01

An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

Biological activities of some Fluoroquinolones-metal complexes

African Journals Online (AJOL)

McRoy

Background: Metal ions play a vital role in the design of more biologically active drugs. Aim: The paper reviewed the .... 2H2O by direct reaction of copper(II) sulphate pentahydrate with ciprofloxacin in distilled water. ... membered ring and the chloride ion completes the seven coordination around the Ca2+ion.[37-39].

Tailorable chiroptical activity of metallic nanospiral arrays.

Science.gov (United States)

Deng, Junhong; Fu, Junxue; Ng, Jack; Huang, Zhifeng

2016-02-28

The engineering of the chiroptical activity of the emerging chiral metamaterial, metallic nanospirals, is in its infancy. We utilize glancing angle deposition (GLAD) to facilely sculpture the helical structure of silver nanospirals (AgNSs), so that the scope of chiroptical engineering factors is broadened to include the spiral growth of homochiral AgNSs, the combination of left- and right-handed helical chirality to create heterochiral AgNSs, and the coil-axis alignment of the heterochiral AgNSs. It leads to flexible control over the chiroptical activity of AgNS arrays with respect to the sign, resonance wavelength and amplitude of circular dichroism (CD) in the UV and visible regime. The UV chiroptical mode has a distinct response from the visible mode. Finite element simulation together with LC circuit theory illustrates that the UV irradiation is mainly adsorbed in the metal and the visible is preferentially scattered by the AgNSs, accounting for the wavelength-related chiroptical distinction. This work contributes to broadening the horizons in understanding and engineering chiroptical responses, primarily desired for developing a wide range of potential chiroplasmonic applications.

Effects of metal ions on growth, β-oxidation system, and thioesterase activity of Lactococcus lactis.

Science.gov (United States)

Li, Liang; Ma, Ying

2014-10-01

The effects of divalent metal ions (Ca(2+), Mg(2+), Fe(2+), and Cu(2+)) on the growth, β-oxidation system, and thioesterase activity of Lactococcus lactis were investigated. Different metal ions significantly influenced the growth of L. lactis: Ca(2+) and Fe(2+) accelerated growth, whereas Cu(2+) inhibited growth. Furthermore, Mg(2+) inhibited growth of L. lactis at a low concentration but stimulated growth of L. lactis at a high concentration. The divalent metal ions had significant effects on activity of the 4 key enzymes of the β-oxidation system (acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and thiolase) and thioesterase of L. lactis. The activity of acyl-CoA dehydrogenases increased markedly in the presence of Ca(2+) and Mg(2+), whereas it decreased with 1 mmol/L Fe(2+) or 12 mmol/L Mg(2+). All the metal ions could induce activity of enoyl-CoA hydratase. In addition, 12 mmol/L Mg(2+) significantly stimulated activity of L-3-hydroxyacyl-CoA dehydrogenase, and all metal ions could induce activity of thiolase, although thiolase activity decreased significantly when 0.05 mmol/L Cu(2+) was added into M17 broth. Inhibition of thioesterase activity by all 4 metal ions could be reversed by 2 mmol/L Ca(2+). These results help us understand the effect of metal ions on the β-oxidation system and thioesterase activity of Lactococcus lactis. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effect of metal salts on antibacterial activity of zingiber officinale roscoe extract

International Nuclear Information System (INIS)

Sohail, T.; Yaqeen, Z.; Imran, H.; Rehman, Z.; Fatima, N.

2013-01-01

The antibacterial activity of ethanol extract of Zingiber Officinale Roscoe (ginger) and its combination with different salts like CuSO/sub 4/, ZnSO/sub 4/ and MnCl/sub 2/ was investigated. Both Gram positive and Gram negative bacteria were tested by agar diffusion method. The results showed that ethanol extract of Zingiber Officinale gave the maximum zone of inhibition at 50 mg/ml concentrations against Escherichia coli among Gram negative bacteria and against Staphylococcus aureus in Gram positive bacteria. However antibacterial activity of the ginger and metal salts combination was greater than activity of ethanol extract. These investigations indicate that though ethanol extract has antibacterial activity against Gram positive and Gram negative bacteria, ginger and metal salts complex has more inhibitory effect on microorganisms. Antibacterial activity was also compared with standard drug ampicillin. The minimum inhibitory concentration (MIC) of ginger extract and metal salts complexes against all test organisms ranged from 0.3125 to 2.5 mg/ml. (author)

Transition metal complexes of some biologically active ligands; synthesis characterization and bioactivities

International Nuclear Information System (INIS)

Rehman, S.; Ali, N.; Nisar, M.

2009-01-01

Transition/representative transition metals complexes of biologically active chelating agent 1,2-dipyrolodinoethane were synthesized and characterized through spectral and analytical data. The complexes are of the formula (M(L)X/sub 2/). Where (M = Co (II), Ni (II), Cu (II), Zn (II), Hg (II) and Cd (II) and X = CI, Br, NO/sub 3/). Tetrahedral geometry has been proposed to these-metal complexes with the help of magnetic measurements, elemental analysis, chemical stoichiometry and spectroscopic data Antibacterial activity of the ligand and its metal complexes were screened against Eschereschi coli, Klebsiello pneumonia, Proteus mirabilis, Proteus vulhari, Streptococcus pneumonia, Salmonella Iyphi, Bacilh,s anthrax, Streptococcus fecalis and Staphylococcus aureus. Complexes were found to be active against Eschereschi coli, Klebsiella pneumonia, Proteus mirabilis and Proteus vulharis. (author)

Graphene as a long-term metal oxidation barrier: worse than nothing.

Science.gov (United States)

Schriver, Maria; Regan, William; Gannett, Will J; Zaniewski, Anna M; Crommie, Michael F; Zettl, Alex

2013-07-23

Anticorrosion and antioxidation surface treatments such as paint or anodization are a foundational component in nearly all industries. Graphene, a single-atom-thick sheet of carbon with impressive impermeability to gases, seems to hold promise as an effective anticorrosion barrier, and recent work supports this hope. We perform a complete study of the short- and long-term performance of graphene coatings for Cu and Si substrates. Our work reveals that although graphene indeed offers effective short-term oxidation protection, over long time scales it promotes more extensive wet corrosion than that seen for an initially bare, unprotected Cu surface. This surprising result has important implications for future scientific studies and industrial applications. In addition to informing any future work on graphene as a protective coating, the results presented here have implications for graphene's performance in a wide range of applications.

Screening of active metals for reactive adsorption desulfurization adsorbent using density functional theory

Energy Technology Data Exchange (ETDEWEB)

Wang, Lei; Zhao, Liang, E-mail: liangzhao@cup.edu.cn; Xu, Chunming; Wang, Yuxian; Gao, Jinsen

2017-03-31

Highlights: • Electronic characteristics determined adsorption characteristics of transition metals. • Cobalt has the similar adsorption ability of thiophene as nickel. • Adsorption capacity of Cr and Mo was extremely fierce, while Cu has the potential ability for adsorbing thiophene. • The preference adsorption site for thiophene was hollow site on all the seven surface. - Abstract: To explore characteristics of active metals for reactive adsorption desulfurization (RADS) technology, the adsorption of thiophene on M (100) (M = Cr, Mo, Co, Ni, Cu, Au, and Ag) surfaces was systematically studied by density functional theory with vdW correction (DFT + D3). We found that, in all case, the most stable molecular adsorption site was the hollow site and adsorptive capabilities of thiophene followed the order: Cr > Mo > Co ≈ Ni > Cu > Au ≈ Ag. By analyzing the nature of binding between thiophene and corresponding metals and the electronic structure of metals, the excessive activities of Cr and Mo were found to have a negative regeneration, the passive activities of Au and Ag were found to have an inactive adsorption for RADS adsorbent alone, while Ni and Co have appropriate characteristics as the active metals for RADS, followed by Cu.

Zirconium coatings doped with nanoparticles for the protection of stainless steel

International Nuclear Information System (INIS)

Pineda, F; Vargas, E; Martinez, C; Sancy, M; Rabagliati, F.M; Pavez, J; Paez, M.A

2008-01-01

The anticorrosive protection of metal alloys, like stainless steel, is usually carried out with chrome-based coatings, but the toxic wastes associated with the process minimizes its applicability. The above has motivated the search for alternative protection methodologies, among which are the inorganic polymers prepared by the sol-gel method, which are a viable protection alternative because of their outstanding chemical and physical properties in aggressive environments. Despite the method's benefits, the application of sol-gel coatings to metals exposed to highly corrosive materials is restricted due to the substantial porosity of the films. Recent studies report that this limiting factor can be diminished by adding inorganic nanoparticles to the polymeric matrices, significantly improving the anticorrosive properties of the coatings. Considering the above, this work evaluated the inclusion of iron oxide nanoparticles (III) in zirconium polymeric matrices for the protection of 316 and 316L stainless steel. Electrochemical techniques, such as polarization curves and electrochemical impedance spectroscopy and morphological analysis with atomic force microscopy were used for this purpose. The responses obtained showed improvements in the anticorrosive properties of the zirconium films when doped with nanoparticles, and the best protective response was obtained with the minimum amount of the nanomaterial, aided by a significant increase in the metallic material's passivity. A critical content of nanoparticles was also identified in the polymeric matrix, above which the coating suffers serious deterioration, caused by the apparent formation of percolation channels leading to the oversaturation of the polymeric matrix

Hydrogen evolution activity and electrochemical stability of selected transition metal carbides in concentrated phosphoric acid

DEFF Research Database (Denmark)

Tomás García, Antonio Luis; Jensen, Jens Oluf; Bjerrum, Niels J.

2014-01-01

phosphoric acid were investigated in a temperature range from 80 to 170°C. A significant dependence of the activities on temperature was observed for all five carbide samples. Through the entire temperature range Group 6 metal carbides showed higher activity than that of the Group 5 metal carbides......Alternative catalysts based on carbides of Group 5 (niobium and tantalum) and 6 (chromium, molybdenum and tungsten) metals were prepared as films on the metallic substrates. The electrochemical activities of these carbide electrodes towards the hydrogen evolution reaction (HER) in concentrated...

Electrochemical and anticorrosion behaviors of hybrid functionalized graphite nano-platelets/tripolyphosphate in epoxy-coated carbon steel

International Nuclear Information System (INIS)

Mohammadi, Somayeh; Shariatpanahi, Homeira; Taromi, Faramarz Afshar; Neshati, Jaber

2016-01-01

Highlights: • FGNP was combined with TPP to obtain a hybrid nano-particle. • TEM image showed uniform distribution of the hybrid nanoparticles in epoxy coating. • FGNP is a substrate for linking of TPP anions by hydrogen bonding. • FGNP as an accelerator, provides rapid iron phosphate passive film formation. • The hybrid nano-particle can provide long-term corrosion protection. - Abstract: Functionalized graphite nano-platelets (FGNP) were combined with tripolyphosphate (TPP) to gain a hybrid nano-particle (FGNP-TPP) with homogenous dispersion in epoxy, resulting in an excellent anti-corrosion coating for carbon steel substrate. Characterization analyses of the hybrid nano-particle were performed by FT-IR, SEM, XRD and TEM. TPP was linked to FGNP nano-particles by hydrogen bondings. Different epoxy coatings formulated with 1 wt.% of FGNP, FGNP-TPP and TPP were evaluated. Electrochemical investigations, salt spray and pull-off tests showed that the hybrid nano-particle can provide long-term corrosion protection compared to FGNP and TPP due to synergistic effect between FGNP as an accelerator and TPP as a corrosion inhibitor to produce a uniform and stable iron-phosphate passive film with high surface coverage.

Electrochemical and anticorrosion behaviors of hybrid functionalized graphite nano-platelets/tripolyphosphate in epoxy-coated carbon steel

Energy Technology Data Exchange (ETDEWEB)

Mohammadi, Somayeh, E-mail: somaye.mohammadi32@aut.ac.ir [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shariatpanahi, Homeira [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Taromi, Faramarz Afshar [Department of Polymer Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Neshati, Jaber [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of)

2016-08-15

Highlights: • FGNP was combined with TPP to obtain a hybrid nano-particle. • TEM image showed uniform distribution of the hybrid nanoparticles in epoxy coating. • FGNP is a substrate for linking of TPP anions by hydrogen bonding. • FGNP as an accelerator, provides rapid iron phosphate passive film formation. • The hybrid nano-particle can provide long-term corrosion protection. - Abstract: Functionalized graphite nano-platelets (FGNP) were combined with tripolyphosphate (TPP) to gain a hybrid nano-particle (FGNP-TPP) with homogenous dispersion in epoxy, resulting in an excellent anti-corrosion coating for carbon steel substrate. Characterization analyses of the hybrid nano-particle were performed by FT-IR, SEM, XRD and TEM. TPP was linked to FGNP nano-particles by hydrogen bondings. Different epoxy coatings formulated with 1 wt.% of FGNP, FGNP-TPP and TPP were evaluated. Electrochemical investigations, salt spray and pull-off tests showed that the hybrid nano-particle can provide long-term corrosion protection compared to FGNP and TPP due to synergistic effect between FGNP as an accelerator and TPP as a corrosion inhibitor to produce a uniform and stable iron-phosphate passive film with high surface coverage.

Corrosion resistance properties of enamels with high B2O3-P2O5 content to molten aluminum

International Nuclear Information System (INIS)

Zhou, M.; Li, K.; Shu, D.; Sun, B.D.; Wang, J.

2003-01-01

Anticorrosive properties of borophosphate and boron-free enamels to molten aluminum were investigated using SEM and electron probe. Carbonates of alkali metal and alkaline earth metal were added in an appropriate weight ratio to achieve desired melting temperature of the enamels. SEM examination on the solidified interface between the enamels and aluminum alloy show that the enamels can spread slightly on aluminum alloy. For anticorrosive sample of borophosphate enamel, phosphorus was not detected by electron probe at the side of aluminum alloy near the interface, but silicon was detected in the silica-free enamels side. For the sample of boron-free enamels, however, phosphorus was found at the side of aluminum alloy near the interface. It was revealed that the enamels with high B 2 O 3 -P 2 O 5 content have high corrosion resistance to molten aluminum

Assessment of Trace Metals in Soil, Vegetation and Rodents in Relation to Metal Mining Activities in an Arid Environment.

Science.gov (United States)

Méndez-Rodríguez, Lia C; Alvarez-Castañeda, Sergio Ticul

2016-07-01

Areas where abandoned metal-extraction mines are located contain large quantities of mineral wastes derived from environmentally unsafe mining practices. These wastes contain many pollutants, such as heavy metals, which could be released to the environment through weathering and leaching, hence becoming an important source of environmental metal pollution. This study evaluates differences in the levels of lead, iron, nickel, manganese, copper and cadmium in rodents sharing the same type of diet under different microhabitat use in arid areas with past mining activities. Samples of soil, roots, branches and seeds of Palo Adán (Fouquieria diguetii) and specimens of two rodent species (Chaetodipus arenarius and C. spinatus) were collected in areas with impact from past metal mining activities as well as from areas with no mining impact. Both rodent species mirrored nickel and iron levels in soil and seeds, as well as lead levels in soil; however, C. arenarius accumulated higher levels of manganese, copper and cadmium.

Validation of Transfer Functions Predicting Cd and Pb Free Metal Ion Activity in Soil Solution as a Function of Soil Characteristics and Reactive Metal Content

NARCIS (Netherlands)

Pampura, T.; Groenenberg, J.E.; Lofts, S.; Priputina, I.

2007-01-01

According to recent insight, the toxicity of metals in soils is better related to the free metal ion (FMI) activity in the soil solution than to the total metal concentration in soil. However, the determination of FMI activities in soil solution is a difficult and time-consuming task. An alternative

Large Area Active Brazing of Multi-tile Ceramic-Metal Structures

Science.gov (United States)

2012-05-01

metallurgical bonds. The major disadvantage of using active brazing for metals and ceramics is the high processing temperature required that results in...steels) and form strong, metallurgical bonds. However, the high processing temperatures result in large strain (stress) build-up from the inherent...metals such as titanium alloys and stainless steels) and form strong, metallurgical bonds. However, the high processing temperatures result in large

Mechanism of Metal Ion Activation of the Diphtheria Toxin Repressor DtxR

Energy Technology Data Exchange (ETDEWEB)

D' Aquino,J.; Tetenbaum-Novatt, J.; White, A.; Berkovitch, F.; Ringe, D.

2005-01-01

The diphtheria toxin repressor (DtxR) is a metal ion-activated transcriptional regulator that has been linked to the virulence of Corynebacterium diphtheriae. Structure determination has shown that there are two metal ion binding sites per repressor monomer, and site-directed mutagenesis has demonstrated that binding site 2 (primary) is essential for recognition of the target DNA repressor, leaving the role of binding site 1 (ancillary) unclear. Calorimetric techniques have demonstrated that although binding site 1 (ancillary) has high affinity for metal ion with a binding constant of 2 x 10{sup -7}, binding site 2 (primary) is a low-affinity binding site with a binding constant of 6.3 x 10{sup -4}. These two binding sites act in an independent fashion, and their contribution can be easily dissected by traditional mutational analysis. Our results clearly demonstrate that binding site 1 (ancillary) is the first one to be occupied during metal ion activation, playing a critical role in stabilization of the repressor. In addition, structural data obtained for the mutants Ni-DtxR(H79A, C102D), reported here, and the previously reported DtxR(H79A) have allowed us to propose a mechanism of metal activation for DtxR.

Catalytic activity of metall-like carbides in carbon oxide oxidation reaction

International Nuclear Information System (INIS)

Kharlamov, A.I.; Kosolapova, T.Ya.; Rafal, A.N.; Kirillova, N.V.

1980-01-01

Kinetics of carbon oxide oxidation upon carbides of hafnium, niobium, tantalum, molybdenum, zirconium and chromium is studied. Probable mechanism of the catalysts action is suggested. The established character of the change of the carbide catalytic activity is explained by the change of d-electron contribution to the metal-metal interaction

Uranyl oxo activation and functionalization by metal cation coordination

International Nuclear Information System (INIS)

Arnold Polly, L.; Pecharman, A. F.; Hollis, E.; Parsons, S.; Love, J. B.; Yahia, A.; Maron, L.; Yahia, A.; Maron, L.

2010-01-01

The oxo groups in the uranyl ion [UO 2 ] 2+ - one of many oxo cations formed by metals from across the periodic table - are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a 'Pacman' environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C-H bond activation reactions are occurring. (authors)

Functional Coatings or Films for Hard-Tissue Applications

Directory of Open Access Journals (Sweden)

Guocheng Wang

2010-07-01

Full Text Available Metallic biomaterials like stainless steel, Co-based alloy, Ti and its alloys are widely used as artificial hip joints, bone plates and dental implants due to their excellent mechanical properties and endurance. However, there are some surface-originated problems associated with the metallic implants: corrosion and wear in biological environments resulting in ions release and formation of wear debris; poor implant fixation resulting from lack of osteoconductivity and osteoinductivity; implant-associated infections due to the bacterial adhesion and colonization at the implantation site. For overcoming these surface-originated problems, a variety of surface modification techniques have been used on metallic implants, including chemical treatments, physical methods and biological methods. This review surveys coatings that serve to provide properties of anti-corrosion and anti-wear, biocompatibility and bioactivity, and antibacterial activity.

Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon.

Science.gov (United States)

Bandarenka, Hanna V; Girel, Kseniya V; Zavatski, Sergey A; Panarin, Andrei; Terekhov, Sergei N

2018-05-21

The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS) with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs), and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy.

Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon

Directory of Open Access Journals (Sweden)

Hanna V. Bandarenka

2018-05-01

Full Text Available The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs, and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy.

Metal adsorption process in activated carbon fiber from textile PAN fiber aim electrode production

International Nuclear Information System (INIS)

Rodrigues, Aline Castilho; Goncalves, Emerson Sarmento; Silva, Elen Leal da; Marcuzzo, Jossano Saldanha; Baldan, Mauricio Ribeiro; Cuna, Andres

2016-01-01

Full text: Carbon fibers have a variety of applications in industry and have been increasingly studied to explore their various characteristics. Studies show that the activated carbon fiber has been effective in removing small contaminants as well as activated carbon, because of its characteristic porosity. Other studies relate carbonaceous materials to the electrical conductivity devices application. This work is based on the use of an activated carbon fiber from textile polyacrylonitrile (PAN) for metallic ion adsorption from aqueous solution. Consequently, it improves the electrical characteristics and this fact show the possibility to use this material as electrode. The work was performed by adsorption process in saline solution (NO 3 Ag and ClPd) and activated carbon fiber in felt form as adsorbent. The metal adsorption on activated carbon fiber was characterized by textural analysis, x-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive x-ray (SEM-EDX), Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). It was observed that activated carbon fiber showed good adsorption capacity for the metals used. At the end of the process, the activated carbon fiber samples gained about 15% by weight, related to metallic fraction incorporated into the fiber and the process of adsorption does not changed the structural, morphological and chemistry inertness of the samples. The results indicate the feasibility of this metal incorporation techniques activated carbon fiber for the production of electrodes facing the electrochemical area. (author)

Metal adsorption process in activated carbon fiber from textile PAN fiber aim electrode production

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Aline Castilho; Goncalves, Emerson Sarmento, E-mail: alinerodrigues_1@msn.com [Instituto Tecnologico Aeroespacial (ITA), Sao Jose dos Campos, SP (Brazil); Silva, Elen Leal da; Marcuzzo, Jossano Saldanha; Baldan, Mauricio Ribeiro [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Cuna, Andres [Faculdade de Quimica, Universidad de la Republica (Uruguay)

2016-07-01

Full text: Carbon fibers have a variety of applications in industry and have been increasingly studied to explore their various characteristics. Studies show that the activated carbon fiber has been effective in removing small contaminants as well as activated carbon, because of its characteristic porosity. Other studies relate carbonaceous materials to the electrical conductivity devices application. This work is based on the use of an activated carbon fiber from textile polyacrylonitrile (PAN) for metallic ion adsorption from aqueous solution. Consequently, it improves the electrical characteristics and this fact show the possibility to use this material as electrode. The work was performed by adsorption process in saline solution (NO{sub 3}Ag and ClPd) and activated carbon fiber in felt form as adsorbent. The metal adsorption on activated carbon fiber was characterized by textural analysis, x-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive x-ray (SEM-EDX), Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). It was observed that activated carbon fiber showed good adsorption capacity for the metals used. At the end of the process, the activated carbon fiber samples gained about 15% by weight, related to metallic fraction incorporated into the fiber and the process of adsorption does not changed the structural, morphological and chemistry inertness of the samples. The results indicate the feasibility of this metal incorporation techniques activated carbon fiber for the production of electrodes facing the electrochemical area. (author)

Adsorption of phenol on metal treated by granular activated carbon

International Nuclear Information System (INIS)

Kang, Kwang Cheol; Kwon, Soo Han; Kim, Seung Soo; Baik, Min Hoon; Choi, Jong Won; Kim, Jin Won

2007-01-01

In this study, the effect of metal treatment on Granular Activated Carbon (GAC) was investigated in the context of phenol adsorption. Cobalt(II) nitrate, and zinc(II) nitrate solution were used for metal treated. The specific surface area and the pore structure were evaluated from nitrogen adsorption data at 77 K. The phenol adsorption rates onto GAC were measured by UV-Vis spectrophotometer. Iodine adsorption capacity of Co-GAC is much better then that of the GAC. The Co-GAC with mesopore is more efficient than other adsorbents for the adsorption of polymer such as methyleneblue. The adsorption capacity of reference-GAC and metal-GAC were increased in order of Co-GAC>Zn-GAC>Reference-GAC, in spite of a decrease in specific surface area which was resulted from pore blocking by metal

Photo-Curable Metal-Chelating Coatings Offer a Scalable Approach to Production of Antioxidant Active Packaging.

Science.gov (United States)

Lin, Zhuangsheng; Goddard, Julie

2018-02-01

Synthetic metal chelators (for example, ethylenediaminetetraacetic acid, EDTA) are widely used as additives to control trace transition metal induced oxidation in consumer products. To enable removal of synthetic chelators in response to increasing consumer demand for clean label products, metal-chelating active food packaging technologies have been developed with demonstrated antioxidant efficacy in simulated food systems. However, prior work in fabrication of metal-chelating materials leveraged batch chemical reactions to tether metal-chelating ligands, a process with limited industrial translatability for large-scale fabrication. To improve the industrial translatability, we have designed a 2-step laminated photo-grafting process to introduce metal chelating functionality onto common polymeric packaging materials. Iminodiacetic acid (IDA) functionalized materials were fabricated by photo-grafting poly(acrylic acid) onto polypropylene (PP) films, followed by a second photo-grafting process to graft-polymerize an IDA functionalized vinyl monomer (GMA-IDA). The photo-grafting was conducted under atmospheric conditions and was completed in 2 min. The resulting IDA functionalized metal-chelating material was able to chelate iron and copper, and showed antioxidant efficacy against ascorbic acid degradation, supporting its potential to be used synergistically with natural antioxidants for preservation of food and beverage products. The 2-step photo-grafting process improves the throughput of active packaging coatings, enabling potential roll-to-roll fabrication of metal-chelating active packaging materials for antioxidant food packaging applications. To address consumer and retail demands for "clean label" foods and beverages without a corresponding loss in product quality and shelf life, producers are seeking next generation technologies such as active packaging. In this work, we will report the synthesis of metal-chelating active packaging films, which enable removal

Synthesis of Single-Walled Carbon Nanotubes: Effects of Active Metals, Catalyst Supports, and Metal Loading Percentage

Directory of Open Access Journals (Sweden)

Wei-Wen Liu

2013-01-01

Full Text Available The effects of active metals, catalyst supports, and metal loading percentage on the formation of single-walled carbon nanotubes (SWNTs were studied. In particular, iron, cobalt, and nickel were investigated for SWNTs synthesis. Iron was found to grow better-quality SWNTs compared to cobalt and nickel. To study the effect of catalyst supports, magnesium oxide, silicon oxide, and aluminium oxide were chosen for iron. Among the studied supports, MgO was identified to be a suitable support for iron as it produced SWNTs with better graphitisation determined by Raman analysis. Increasing the iron loading decreased the quality of SWNTs due to extensive agglomeration of the iron particles. Thus, lower metal loading percentage is preferred to grow better-quality SWNTs with uniform diameters.

Synthesis and Antibacterial Activity of Metal(loid Nanostructures by Environmental Multi-Metal(loid Resistant Bacteria and Metal(loid-Reducing Flavoproteins

Directory of Open Access Journals (Sweden)

Maximiliano Figueroa

2018-05-01

Full Text Available Microbes are suitable candidates to recover and decontaminate different environments from soluble metal ions, either via reduction or precipitation to generate insoluble, non-toxic derivatives. In general, microorganisms reduce toxic metal ions generating nanostructures (NS, which display great applicability in biotechnological processes. Since the molecular bases of bacterial reduction are still unknown, the search for new -environmentally safe and less expensive- methods to synthesize NS have made biological systems attractive candidates. Here, 47 microorganisms isolated from a number of environmental samples were analyzed for their tolerance or sensitivity to 19 metal(loids. Ten of them were highly tolerant to some of them and were assessed for their ability to reduce these toxicants in vitro. All isolates were analyzed by 16S rRNA gene sequencing, fatty acids composition, biochemical tests and electron microscopy. Results showed that they belong to the Enterobacter, Staphylococcus, Acinetobacter, and Exiguobacterium genera. Most strains displayed metal(loid-reducing activity using either NADH or NADPH as cofactor. While Acinetobacter schindleri showed the highest tellurite (TeO32- and tetrachloro aurate (AuCl4- reducing activity, Staphylococcus sciuri and Exiguobacterium acetylicum exhibited selenite (SeO32- and silver (Ag+ reducing activity, respectively. Based on these results, we used these bacteria to synthetize, in vivo and in vitro Te, Se, Au, and Ag-containing nanostructures. On the other hand, we also used purified E. cloacae glutathione reductase to synthesize in vitro Te-, Ag-, and Se-containing NS, whose morphology, size, composition, and chemical composition were evaluated. Finally, we assessed the putative anti-bacterial activity exhibited by the in vitro synthesized NS: Te-containing NS were more effective than Au-NS in inhibiting Escherichia coli and Listeria monocytogenes growth. Aerobically synthesized TeNS using MF09 crude

Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

International Nuclear Information System (INIS)

Ruiz, E.; Alonso-Azcarate, J.; Rodriguez, L.

2011-01-01

The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils. - Research highlights: → Lumbricus terrestris L. activity increases the bioavailability of metals in soils. → Earthworm activity can significantly increase total, shoot and root metal concentrations for crop plants. → Both bioassays and chemical extraction methods are necessary for assessing the bioavailability of metals in contaminated soils. - Lumbricus terrestris L. activity increases the bioavailability of metals in soils and total, shoot and root metal concentrations for maize and barley.

Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

Energy Technology Data Exchange (ETDEWEB)

Ruiz, E. [Department of Chemical Engineering, School of Civil Engineering, University of Castilla-La Mancha, Avenida Camilo Jose Cela, s/n, 13071 Ciudad Real (Spain); Alonso-Azcarate, J. [Department of Physical Chemistry, Faculty of Environmental Sciences, University of Castilla-La Mancha, Avenida Carlos III, s/n, 45071 Toledo (Spain); Rodriguez, L., E-mail: Luis.Rromero@uclm.es [Department of Chemical Engineering, School of Civil Engineering, University of Castilla-La Mancha, Avenida Camilo Jose Cela, s/n, 13071 Ciudad Real (Spain)

2011-03-15

The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils. - Research highlights: > Lumbricus terrestris L. activity increases the bioavailability of metals in soils. > Earthworm activity can significantly increase total, shoot and root metal concentrations for crop plants. > Both bioassays and chemical extraction methods are necessary for assessing the bioavailability of metals in contaminated soils. - Lumbricus terrestris L. activity increases the bioavailability of metals in soils and total, shoot and root metal concentrations for maize and barley.

Short-time effect of heavy metals upon microbial community activity

International Nuclear Information System (INIS)

Wang Fei; Yao Jun; Si Yang; Chen Huilun; Russel, Mohammad; Chen Ke; Qian Yiguang; Zaray, Gyula; Bramanti, Emilia

2010-01-01

Microcalorimetry was applied to assess and compare the toxic effect of heavy metals, such as As, Cu, Cd, Cr, Co, Pb and Zn, on the soil microbial activities and community. About 1.0 g soil spiked 5.0 mg glucose and 5.0 mg ammonium sulfate, the microbial activities were recorded as power-time curves, and their indices, microbial growth rate constant k, total heat evolution Q T , metabolic enthalpy ΔH met and mass specific heat rate J Q/S , were calculated. Comparing these thermodynamic parameters associated with growth yield, a general order of toxicity to the soil was found to be Cr > Pb > As > Co > Zn > Cd > Cu. When soil was exposed to heavy metals, the amount of bacteria and fungi decreased with the incubation time, and the bacterial number diminished sharply. It illustrates that fungi are more tolerant, and bacteria-fungi ratio would be altered under metal stress. To determine the status of the glucose consumed, a glucose biosensor with eggshell membrane was used to measure the remaining glucose in soil sample. Results showed that the time at which glucose was consumed completely was agreed with the microcalorimetric time to a large extent, and depended on the toxicity of heavy metals as well.

Short-time effect of heavy metals upon microbial community activity.

Science.gov (United States)

Wang, Fei; Yao, Jun; Si, Yang; Chen, Huilun; Russel, Mohammad; Chen, Ke; Qian, Yiguang; Zaray, Gyula; Bramanti, Emilia

2010-01-15

Microcalorimetry was applied to assess and compare the toxic effect of heavy metals, such as As, Cu, Cd, Cr, Co, Pb and Zn, on the soil microbial activities and community. About 1.0 g soil spiked 5.0mg glucose and 5.0mg ammonium sulfate, the microbial activities were recorded as power-time curves, and their indices, microbial growth rate constant k, total heat evolution Q(T), metabolic enthalpy Delta H(met) and mass specific heat rate J(Q/S), were calculated. Comparing these thermodynamic parameters associated with growth yield, a general order of toxicity to the soil was found to be Cr>Pb>As>Co>Zn>Cd>Cu. When soil was exposed to heavy metals, the amount of bacteria and fungi decreased with the incubation time, and the bacterial number diminished sharply. It illustrates that fungi are more tolerant, and bacteria-fungi ratio would be altered under metal stress. To determine the status of the glucose consumed, a glucose biosensor with eggshell membrane was used to measure the remaining glucose in soil sample. Results showed that the time at which glucose was consumed completely was agreed with the microcalorimetric time to a large extent, and depended on the toxicity of heavy metals as well.

Short-time effect of heavy metals upon microbial community activity

Energy Technology Data Exchange (ETDEWEB)

Wang Fei [Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health and School of Environmental Sciences, China University of Geosciences, 430074 Wuhan (China); Yao Jun, E-mail: yaojun@cug.edu.cn [Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health and School of Environmental Sciences, China University of Geosciences, 430074 Wuhan (China); Si Yang; Chen Huilun; Russel, Mohammad; Chen Ke; Qian Yiguang [Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education and Sino-Hungarian Joint Laboratory of Environmental Science and Health and School of Environmental Sciences, China University of Geosciences, 430074 Wuhan (China); Zaray, Gyula [Department of Chemical Technology and Environmental Chemistry, Eoetvoes University, H-1518 Budapest, P.O. Box 32 (Hungary); Bramanti, Emilia [Laboratory of Instrumental Analytical Chemistry, Institute for Chemical and Physical Processes, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

2010-01-15

Microcalorimetry was applied to assess and compare the toxic effect of heavy metals, such as As, Cu, Cd, Cr, Co, Pb and Zn, on the soil microbial activities and community. About 1.0 g soil spiked 5.0 mg glucose and 5.0 mg ammonium sulfate, the microbial activities were recorded as power-time curves, and their indices, microbial growth rate constant k, total heat evolution Q{sub T}, metabolic enthalpy {Delta}H{sub met} and mass specific heat rate J{sub Q/S}, were calculated. Comparing these thermodynamic parameters associated with growth yield, a general order of toxicity to the soil was found to be Cr > Pb > As > Co > Zn > Cd > Cu. When soil was exposed to heavy metals, the amount of bacteria and fungi decreased with the incubation time, and the bacterial number diminished sharply. It illustrates that fungi are more tolerant, and bacteria-fungi ratio would be altered under metal stress. To determine the status of the glucose consumed, a glucose biosensor with eggshell membrane was used to measure the remaining glucose in soil sample. Results showed that the time at which glucose was consumed completely was agreed with the microcalorimetric time to a large extent, and depended on the toxicity of heavy metals as well.

Uranyl oxo activation and functionalization by metal cation coordination

Energy Technology Data Exchange (ETDEWEB)

Arnold Polly, L; Pecharman, A F; Hollis, E; Parsons, S; Love, J B [Univ Edinburgh, EaStCHEM Sch Chem, Edinburgh EH9 3JJ, Midlothian (United Kingdom); Yahia, A; Maron, L [Univ Toulouse 3, LPCNO, UMR 5215, INSA, CNRS, F-31077 Toulouse 4 (France); Yahia, A; Maron, L [Univ Montpellier 2, ENSCM, CNRS, ICSM, UMR 5257, CEA, Ctr Marcoule, F-30207 Bagnols Sur Ceze (France)

2010-07-01

The oxo groups in the uranyl ion [UO{sub 2}]{sup 2+} - one of many oxo cations formed by metals from across the periodic table - are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a 'Pacman' environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C-H bond activation reactions are occurring. (authors)

Neutron activation analysis of heavy metal binding by fungal cell walls

International Nuclear Information System (INIS)

Crusberg, T.C.; Mayer, J.A.

1994-01-01

Aqueous effluents are produced during nuclear power and nuclear weapons development activities which frequently contain low levels of dissolved radioactive nuclides. A number of laboratories are now focusing attention to renewable biological materials to provide traps for low concentrations of dissolved radioactive metal ions in wastewater effluents. The term BIOTRAP can be used to describe such materials, and in this laboratory cell wall preparations of the fungus Penicillium ochro-chloron have been employed to demonstrate their capacity and affinity to reversibly bind and remove copper(2). Since neutron activation analysis (NAA) was readily available, that method was one of several applied to this problem as a suitable analytical methodology to study heavy metal-to-BIOTRAP interactions. Copper and mercury provide good examples of metals which are capable of undergoing activation by thermal neutrons. In NAA, 63 Cu (69.1% natural abundance) is converted to 64 Cu which has a half live of 12.7 hr, and 202 Hg (29.7 % natural abundance) is converted to 203 Hg which has a half life of 46.,6 d

Fast and low-cost method to fabricate large-area superhydrophobic surface on steel substrate with anticorrosion and anti-icing properties

Energy Technology Data Exchange (ETDEWEB)

Yan, Wei; Liu, Hongtao, E-mail: liuht100@126.com; Sun, Qinghe; Zhu, Wei [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Chen, Tianchi [College of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China)

2016-07-15

A facile and quick fabrication method was proposed to prepare superhydrophobic surfaces on iron substrate by chemical immersion and subsequent stearic acid modification. The association between wettability and surface morphology was studied through altering the copper ion concentration and immersion time. Surface tension instrument, scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and electrochemical workstation were used to characterize the wettability, physical morphology, chemical composition, and corrosion resistance ability of the prepared film. Results showed that both the rough micro/nanostructures and low surface energy material play critical roles in surface wettability. The superhydrophobic film achieved a better anticorrosion property compared to barrier iron by analysis of open circuit potential, potentiodynamic polarization curves, and Nyquist plots. In addition, the superhydrophobic surface showed excellent performance of acid and alkali resistance, anti-icing, and self-cleaning through a series of environmental tests. This study provides a valid method for quick-preparation of the stable superhydrophobic surfaces, which has a promising application in steel buildings and facilities.

Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

Science.gov (United States)

Özkan, İ.; Duru Baykal, P.

2017-10-01

In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

Science.gov (United States)

Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

2016-03-01

The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

Ibandronate metal complexes: solution behavior and antiparasitic activity.

Science.gov (United States)

Demoro, Bruno; Rostán, Santiago; Moncada, Mauricio; Li, Zhu-Hong; Docampo, Roberto; Olea Azar, Claudio; Maya, Juan Diego; Torres, Julia; Gambino, Dinorah; Otero, Lucía

2018-03-01

To face the high costs of developing new drugs, researchers in both industry and academy are looking for ways to repurpose old drugs for new uses. In this sense, bisphosphonates that are clinically used for bone diseases have been studied as agents against Trypanosoma cruzi, causative parasite of Chagas disease. In this work, the development of first row transition metal complexes (M = Co 2+ , Mn 2+ , Ni 2+ ) with the bisphosphonate ibandronate (iba, H 4 iba representing the neutral form) is presented. The in-solution behavior of the systems containing iba and the selected 3d metal ions was studied by potentiometry. Mononuclear complexes [M(H x iba)] (2-x)- (x = 0-3) and [M(Hiba) 2 ] 4- together with the formation of the neutral polynuclear species [M 2 iba] and [M 3 (Hiba) 2 ] were detected for all studied systems. In the solid state, complexes of the formula [M 3 (Hiba) 2 (H 2 O) 4 ]·6H 2 O were obtained and characterized. All obtained complexes, forming [M(Hiba)] - species under the conditions of the biological studies, were more active against the amastigote form of T. cruzi than the free iba, showing no toxicity in mammalian Vero cells. In addition, the same complexes were selective inhibitors of the parasitic farnesyl diphosphate synthase (FPPS) enzyme showing poor inhibition of the human one. However, the increase of the anti-T. cruzi activity upon coordination could not be explained neither through the inhibition of TcFPPS nor through the inhibition of TcSPPS (T. cruzi solanesyl-diphosphate synthase). The ability of the obtained metal complexes of catalyzing the generation of free radical species in the parasite could explain the observed anti-T. cruzi activity.

Highly Active Non-PGM Catalysts Prepared from Metal Organic Frameworks

Directory of Open Access Journals (Sweden)

Heather M. Barkholtz

2015-06-01

Full Text Available Finding inexpensive alternatives to platinum group metals (PGMs is essential for reducing the cost of proton exchange membrane fuel cells (PEMFCs. Numerous materials have been investigated as potential replacements of Pt, of which the transition metal and nitrogen-doped carbon composites (TM/Nx/C prepared from iron doped zeolitic imidazolate frameworks (ZIFs are among the most active ones in catalyzing the oxygen reduction reaction based on recent studies. In this report, we demonstrate that the catalytic activity of ZIF-based TM/Nx/C composites can be substantially improved through optimization of synthesis and post-treatment processing conditions. Ultimately, oxygen reduction reaction (ORR electrocatalytic activity must be demonstrated in membrane-electrode assemblies (MEAs of fuel cells. The process of preparing MEAs using ZIF-based non-PGM electrocatalysts involves many additional factors which may influence the overall catalytic activity at the fuel cell level. Evaluation of parameters such as catalyst loading and perfluorosulfonic acid ionomer to catalyst ratio were optimized. Our overall efforts to optimize both the catalyst and MEA construction process have yielded impressive ORR activity when tested in a fuel cell system.

In situ crystallized zirconium phenylphosphonate films with crystals vertically to the substrate and their hydrophobic, dielectric, and anticorrosion properties.

Science.gov (United States)

Cui, Zhaohui; Zhang, Fazhi; Wang, Lei; Xu, Sailong; Guo, Xiaoxiao

2010-01-05

The in situ crystallization technique has been utilized to fabricate zirconium phenylphosphonate (ZrPP) films with their hexagonal crystallite perpendicular to the copper substrate. The micro/nano roughness surface structure, as well as the intrinsic hydrophobic characteristic of the surface functional groups, affords ZrPP films excellent hydrophobicity with water contact angle (CA) ranging from 134 degrees to 151 degrees , without any low-surface-energy modification. Particularly, in the corrosive solutions such as acidic or basic solutions over a wide pH from 2 to 12, no obvious fluctuation in CA was observed for all the ZrPP film. The k values of the hydrophobic ZrPP films are in the low-k range (k feature is proposed to bear ZrPP film a more stable low-k value in an ambient atmosphere. Besides, the polarization current of ZrPP films is reduced by 2 orders of magnitude, compared to that of the untreated copper substrate. Even deposited in a vacuum oven for 30 days at room temperature, ZrPP films also show excellent corrosion resistance, indicating a stable anticorrosion property.

C-N Bond Activation and Ring Opening of a Saturated N-Heterocyclic Carbene by Lateral Alkali-Metal-Mediated Metalation.

Science.gov (United States)

Hernán-Gómez, Alberto; Kennedy, Alan R; Hevia, Eva

2017-06-01

Combining alkali-metal-mediated metalation (AMMM) and N-heterocyclic carbene (NHC) chemistry, a novel C-N bond activation and ring-opening process is described for these increasingly important NHC molecules, which are generally considered robust ancillary ligands. Here, mechanistic investigations on reactions of saturated NHC SIMes (SIMes=[:C{N(2,4,6-Me 3 C 6 H 2 )CH 2 } 2 ]) with Group 1 alkyl bases suggest this destructive process is triggered by lateral metalation of the carbene. Exploiting co-complexation and trans-metal-trapping strategies with lower polarity organometallic reagents (Mg(CH 2 SiMe 3 ) 2 and Al(TMP)iBu 2 ), key intermediates in this process have been isolated and structurally defined. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of cerium (IV) ions on the anticorrosion properties of siloxane-poly(methyl methacrylate) based film applied on tin coated steel

Energy Technology Data Exchange (ETDEWEB)

Suegama, P.H. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade de Sao Paulo, CP 61548, 05424-970 Sao Paulo, SP (Brazil); Sarmento, V.H.V. [Departamento Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil); Montemor, M.F. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Benedetti, A.V. [Departamento Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil); de Melo, H.G.; Aoki, I.V. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade de Sao Paulo, CP 61548, 05424-970 Sao Paulo, SP (Brazil); Santilli, C.V., E-mail: santilli@iq.unesp.b [Departamento Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil)

2010-07-15

This work investigates the influence of the addition of cerium (IV) ions on the anticorrosion properties of organic-inorganic hybrid coatings applied to passivated tin coated steel. In order to evaluate the specific effect of cerium (IV) addition on nanostructural features of the organic and inorganic phases of the hybrid coating, the hydrolytic polycondensation of silicon alkoxide and the radical polymerization of the methyl methacrylate (MMA) function were induced separately. The corrosion resistance of the coatings was evaluated by means of linear polarization, Tafel type curves and electrochemical impedance measurements. The impedance results obtained for the hybrid coatings were discussed based on an electrical equivalent circuit used to fit the experimental data. The electrochemical results clearly showed the improvement of the protective properties of the organic-inorganic hybrid coating mainly when the cerium (IV) was added to the organic phase solution precursor, which seemed to be due to the formation of a more uniform and densely reticulated siloxane-PMMA film.

Effect of cerium (IV) ions on the anticorrosion properties of siloxane-poly(methyl methacrylate) based film applied on tin coated steel

International Nuclear Information System (INIS)

Suegama, P.H.; Sarmento, V.H.V.; Montemor, M.F.; Benedetti, A.V.; de Melo, H.G.; Aoki, I.V.; Santilli, C.V.

2010-01-01

This work investigates the influence of the addition of cerium (IV) ions on the anticorrosion properties of organic-inorganic hybrid coatings applied to passivated tin coated steel. In order to evaluate the specific effect of cerium (IV) addition on nanostructural features of the organic and inorganic phases of the hybrid coating, the hydrolytic polycondensation of silicon alkoxide and the radical polymerization of the methyl methacrylate (MMA) function were induced separately. The corrosion resistance of the coatings was evaluated by means of linear polarization, Tafel type curves and electrochemical impedance measurements. The impedance results obtained for the hybrid coatings were discussed based on an electrical equivalent circuit used to fit the experimental data. The electrochemical results clearly showed the improvement of the protective properties of the organic-inorganic hybrid coating mainly when the cerium (IV) was added to the organic phase solution precursor, which seemed to be due to the formation of a more uniform and densely reticulated siloxane-PMMA film.

Abundance, composition and activity of denitrifier communities in metal polluted paddy soils

Science.gov (United States)

Liu, Yuan; Liu, Yongzhuo; Zhou, Huimin; Li, Lianqing; Zheng, Jinwei; Zhang, Xuhui; Zheng, Jufeng; Pan, Genxing

2016-01-01

Denitrification is one of the most important soil microbial processes leading to the production of nitrous oxide (N2O). The potential changes with metal pollution in soil microbial community for N2O production and reduction are not well addressed. In this study, topsoil samples were collected both from polluted and non-polluted rice paddy fields and denitrifier communities were characterized with molecular fingerprinting procedures. All the retrieved nirK sequences could be grouped into neither α- nor β- proteobacteria, while most of the nosZ sequences were affiliated with α-proteobacteria. The abundances of the nirK and nosZ genes were reduced significantly in the two polluted soils. Thus, metal pollution markedly affected composition of both nirK and nosZ denitrifiers. While the total denitrifying activity and N2O production rate were both reduced under heavy metal pollution of the two sites, the N2O reduction rate showed no significant change. These findings suggest that N2O production activity could be sensitive to heavy metal pollution, which could potentially lead to a decrease in N2O emission in polluted paddies. Therefore, metal pollution could have potential impacts on soil N transformation and thus on N2O emission from paddy soils. PMID:26739424

Electrochemical activity of heavy metal oxides in the process of ...

Indian Academy of Sciences (India)

Unknown

2002-02-02

Feb 2, 2002 ... Electrochemical activity of heavy metal oxides in the process of chloride induced .... represents the protective barrier moderating the chloride attack which ... inhibitors and their influence on the physical properties of. Portland ...

Adsorption of heavy metal ions by activated charcoal

International Nuclear Information System (INIS)

Fujikawa, Mitsuo

1978-01-01

The adsorption effect was measured for several kinds of heavy metal ions, Pb 2+ , Cd 2+ , Cu 2+ and Zn 2+ by passing them through activated charcoal beds and changing the pH values of solutions. The test procedure is to keep the pH value of solution more than 10 at first, filter heavy metal hydroxide deposit, measure the remaining ion concentration in filtrate, and also test the influence of the addition of alkali to each kind of ions. The individual test procedure for each kind of ions is explained. As for the Cd ions, after the detailed experimental procedure is explained, the adsorption characteristic line is shown as the relation between the adsorption quantity and the equilibrium concentration of Cd 2+ . The similar test procedure and the adsorption characteristic lines are shown and evaluated about Pb 2+ , Cu 2+ and Zn 2+ . These lines are all linear, but have different adsorption quantity and inclination in relation to heavy metal ion concentration. Concerning the influence of pH to adsorption, the characteristics of pH increase are presented, when alkali is added by various quantities to Zn 2+ , Cu 2+ , Pb 2+ and Cd 2+ . The pH of Pb 2+ increased to about 10 by adding 0.4 cc alkali and saturates, but the pH of the other ions did not saturate by adding less than 1.5 cc alkali. When the water containing heavy metals are treated, Cd 2+ , Pb 2+ , Cu 2+ and Zn 2+ are removed almost satisfactorily by passing them through active charcoal filters and keeping pH at 10. The experimental concentrations are 0.05 ppm at pH 10 in Cd, 0.86 ppm at 10.3 in Pb, 0 ppm at pH 9.6 in Cu, 0.06 ppm at pH 8.8 and 12.4 ppm at pH 9.8 in Zn. (Nakai, Y.)

Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils

International Nuclear Information System (INIS)

Li Yongtao; Becquer, Thierry; Dai Jun; Quantin, Cecile; Benedetti, Marc F.

2009-01-01

The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils. - First evidence of the real free metal ion concentrations in acid mine drainage context in tropical systems

On the methodology of radiochemical neutron activation analysis of noble metals

International Nuclear Information System (INIS)

Chai, C.F.; Ma, S.L.; Mao, X.Y.; Liao, K.N.; Liu, W.C.

1986-01-01

Two different radiochemical procedures were developed: chelate ion resin exchange and amine solvent extraction. Two kinds of new Chinese chelate resins (NANKAI-3926 and BEI-5) and a new long-chain primary amine N 1923 were compared with Srafion NMRR and the tertiary amine N 235 in absorption performance of noble metals, respectively. Influences of various experimental conditions, e.g. sample digestion, acidity, equilibrium time, as well as elution of noble metals, on analytical sensitivity and chemical yield were discussed. Combining with neutron activation, the radiochemical separation procedures developed were used to determine the noble metal contents in the geological samples from Permina/Triassic boundary in South China. (author)

Exploring rhizosphere bacteria of Eichhornia crassipes for metal tolerance and biological activity

Digital Repository Service at National Institute of Oceanography (India)

PrabhaDevi; Gomez, S.; Ribeiro, M.; Deshpande, S.A.; Singh, K.S.; DeSouza, L.

Cl₃, They were further screened for antibiotic sensitivity and biological activity according to Kirby-Bauer disc diffusion method The MTB under metal stress condition showed significant biological activity against clinical pathogens, fouling...

Sorption of Heavy Metal Ions from Mine Wastewater by Activated ...

African Journals Online (AJOL)

Michael

2016-12-02

Dec 2, 2016 ... assess their heavy metal ions adsorption potential. The results show that the .... De-ionised water obtained from the Mineral. Engineering Laboratory of ... Batch adsorption experiment for each of the derived activated carbons ...

Natural and active chemical remediation of toxic metals and radionuclides in the aquatic environment

International Nuclear Information System (INIS)

McPherson, G.; Pintauro, P.; O'Connor, S.; Zhang, J.; Gonzales, R.; Flowers, G.

1993-01-01

The focus of this research is the non-biological, chemical remediation of toxic heavy metals and radionuclides in aquatic environments. This Tulane/Xavier group includes researchers from Chemistry, Chemical Engineering, and Geology. Active methods using novel zeolites and ion exchange membranes are currently being evaluated for use in removing heavy metals from natural waters. In addition, field and laboratory studies of metal ion exchange reactions and competitive, heavy metal adsorption on clay substrates are underway to determine sediment metal sequestering capacity. A summary of progress to date and future work is presented

Catalytic Activities of Noble Metal Phosphides for Hydrogenation and Hydrodesulfurization Reactions

Directory of Open Access Journals (Sweden)

Yasuharu Kanda

2018-04-01

Full Text Available In this work, the development of a highly active noble metal phosphide (NMXPY-based hydrodesulfurization (HDS catalyst with a high hydrogenating ability for heavy oils was studied. NMXPY catalysts were obtained by reduction of P-added noble metals (NM-P, NM: Rh, Pd, Ru supported on SiO2. The order of activities for the hydrogenation of biphenyl was Rh-P > NiMoS > Pd-P > Ru-P. This order was almost the same as that of the catalytic activities for the HDS of dibenzothiophene. In the HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT, the HDS activity of the Rh-P catalyst increased with increasing reaction temperature, but the maximum HDS activity for the NiMoS catalyst was observed at 270 °C. The Rh-P catalyst yielded fully hydrogenated products with high selectivity compared with the NiMoS catalyst. Furthermore, XRD analysis of the spent Rh-P catalysts revealed that the Rh2P phase possessed high sulfur tolerance and resistance to sintering.

Development of METAL-ACTIVE SITE and ZINCCLUSTER tool to predict active site pockets.

Science.gov (United States)

Ajitha, M; Sundar, K; Arul Mugilan, S; Arumugam, S

2018-03-01

The advent of whole genome sequencing leads to increasing number of proteins with known amino acid sequences. Despite many efforts, the number of proteins with resolved three dimensional structures is still low. One of the challenging tasks the structural biologists face is the prediction of the interaction of metal ion with any protein for which the structure is unknown. Based on the information available in Protein Data Bank, a site (METALACTIVE INTERACTION) has been generated which displays information for significant high preferential and low-preferential combination of endogenous ligands for 49 metal ions. User can also gain information about the residues present in the first and second coordination sphere as it plays a major role in maintaining the structure and function of metalloproteins in biological system. In this paper, a novel computational tool (ZINCCLUSTER) is developed, which can predict the zinc metal binding sites of proteins even if only the primary sequence is known. The purpose of this tool is to predict the active site cluster of an uncharacterized protein based on its primary sequence or a 3D structure. The tool can predict amino acids interacting with a metal or vice versa. This tool is based on the occurrence of significant triplets and it is tested to have higher prediction accuracy when compared to that of other available techniques. © 2017 Wiley Periodicals, Inc.

The nature of the active site in heterogeneous metal catalysis

DEFF Research Database (Denmark)

Nørskov, Jens Kehlet; Bligaard, Thomas; Larsen, Britt Hvolbæk

2008-01-01

This tutorial review, of relevance for the surface science and heterogeneous catalysis communities, provides a molecular-level discussion of the nature of the active sites in metal catalysis. Fundamental concepts such as "Bronsted-Evans-Polanyi relations'' and "volcano curves'' are introduced...

Electrochemical activity of heavy metal oxides in the process of ...

Indian Academy of Sciences (India)

Unknown

2002-02-02

Feb 2, 2002 ... Electrochemical activity of heavy metal oxides in the process of chloride induced .... decrease of pH value by MeOx, a synergism of acidic and chloride ... inhibitors and their influence on the physical properties of. Portland ...

Assessment of natural radioactivity and heavy metals in water and soil around seismically active area

International Nuclear Information System (INIS)

Oktay Baykara; Mahmut Dogru; Firat University, Elazig

2010-01-01

The natural radioactivity concentration and some heavy metals in various water and soil samples collected from seismically active area have been determined. Gross-alpha and beta concentrations of different 33 water samples and some heavy metal (Fe, Pb, Cu, K, Mn, Cr and Zn) concentration in 72 soil samples collected from two major fault systems (North and East Anatolian Active Fault Systems) in Turkey have been studied. This survey regarding gross-alpha and beta radioactivity and some heavy metals concentrations was carried out by means of Krieger method using a gross-alpha and beta-counting system and atomic absorption spectrometry (AAS), respectively. Also, gross annual effective dose from the average gross-alpha activity in waters were calculated. (author)

Influence of activated carbon surface acidity on adsorption of heavy metal ions and aromatics from aqueous solution

International Nuclear Information System (INIS)

Sato, Sanae; Yoshihara, Kazuya; Moriyama, Koji; Machida, Motoi; Tatsumoto, Hideki

2007-01-01

Adsorption of toxic heavy metal ions and aromatic compounds onto activated carbons of various amount of surface C-O complexes were examined to study the optimum surface conditions for adsorption in aqueous phase. Cadmium(II) and zinc(II) were used as heavy metal ions, and phenol and nitrobenzene as aromatic compounds, respectively. Activated carbon was de-ashed followed by oxidation with nitric acid, and then it was stepwise out-gassed in helium flow up to 1273 K to gradually remove C-O complexes introduced by the oxidation. The oxidized activated carbon exhibited superior adsorption for heavy metal ions but poor performance for aromatic compounds. Both heavy metal ions and aromatics can be removed to much extent by the out-gassed activated carbon at 1273 K. Removing C-O complexes, the adsorption mechanisms would be switched from ion exchange to Cπ-cation interaction for the heavy metals adsorption, and from some kind of oxygen-aromatics interaction to π-π dispersion for the aromatics

Influence of tool pin in friction stir welding on activated carbon reinforced aluminium metal matrix composite

Science.gov (United States)

DijuSamuel, G.; Raja Dhas, J. Edwin

2017-10-01

This paper focus on impact of tool pin in friction stir welding on activated carbon reinforced aluminium metal matrix composite. For fabrication of metal matrix composite AA6061 is used as matrix and activated carbon is used as reinforcement and it is casted using modified stir casting technique. After casting metal matrix composite has undergone various microstructure tests like SEM,EDAX and XRD. FSW is carried out in this metal matrix composite by choosing various tool pin profile like square,round,Threaded round, hexagon and taper. The quality of welded plates is measured in terms of ultimate tensile strength and hardness.

Complexation of trichlorosalicylic acids by alkaline and first row transition metals as a switch for their antibacterial activity

KAUST Repository

Kumar, Vijay

2017-09-14

3,5,6-trichlorosalicylic acid (TCSA) does not show a good antibacterial activity. In contrast, here metal complexes with TCSA have shown better antibacterial activity for selected bacterial strains with a good degree of selectivity. Amongst the eight synthesized essential metal complexes complexed with TCSA, Mn(II)-TCSA and Ni(II)-TCSA have been found to be more effective with MIC range 20-50 µg/L as compared to control (chloramphenicol). The activity of an individual complex against different microbes was not found to be identical, indicating the usage of an individual metal chelate against a targeted bacterial strain. Further, the protein (BSA) binding constant of TCSA and its metal complexes were determined and ordered as Ca(II)-TCSA > Cu(II)-TCSA > Mg(II)-TCSA >> Mn(II)-TCSA >> Zn(II)-TCSA >>> Ni(II)-TCSA >>> Co(II)-TCSA > Fe(II)-TCSA > TCSA. The present study has confirmed enhanced antibacterial activities and binding constants for metal chelates of TCSA as compared to free TCSA, which seems directly related with the antioxidant activities of these complexes. Further, bearing the ambiguity related to the structural characterization of the metal complexed with TCSA ligands, DFT calculations have been used as the tool to unravel the right environment around the metals, studying basically the relative stability of square planar and octahedral metal complexes with TCSA.

Sizing and melting development activities using noncontaminated metal at the Waste Experimental Reduction Facility

International Nuclear Information System (INIS)

Larsen, M.M.; Logan, J.A.

1984-05-01

EG and G Idaho, Inc., has established the Waste Experimental Reduction Facility (WERF) at the Idaho National Engineering Laboratory (INEL) to develop the capability to reduce the volume that low-level beta/gamma wastes occupy at the disposal site. The work effort at WERF includes a waste sizing development activity (WSDA), a waste melting development activity (WMDA), and a waste incineration development activity (WIDA). This report describes work and developments to date in the WSDA and WMDA with noncontaminated metallic waste in preparation for operations at WERF involving beta/gamma-contaminated metal

Biocorrosion of mild steel and copper used in cooling tower water and its control.

Science.gov (United States)

Li, Xiao Lei; Narenkumar, Jayaraman; Rajasekar, Aruliah; Ting, Yen-Peng

2018-03-01

The present study describes the biocorrosion of mild steel (MS1010) and pure copper (Cu) in cooling water environments (both field and lab study). Electrochemical and surface analyses of both metals were carried out to confirm the corrosion susceptibility in the presence of bacteria and inhibitor. Surface analysis of the MS and Cu coupons revealed that biofilm was developed with increasing exposure time in the field study. In the lab study, accumulation of extracellular polymeric substance over the metal surface was noticed and led to the severe pitting type of corrosion on both metal surfaces. Besides, the anti-corrosive study was carried out using the combinations of commercial corrosion inhibitor (S7653-10 ppm) with biocide (F5100-5 ppm), and the results reveal that the corrosion rate of MS and Cu was highly reduced to 0.0281 and 0.0021 mm/year (inhibitor system) than 0.1589 and 0.0177 mm/year (control system). Inhibition efficiency for both metals in the presence of inhibitor with biocide was found as 82 and 88% for MS and Cu, respectively. The present study concluded that MS was very susceptible to biocorrosion, compared to copper metal in cooling water environment. Further, the combination of the both inhibitor and biocide was effectively inhibiting the biocorrosion which was due to its antibacterial and anti-corrosive properties.

Activity Tests of Macro-Meso Porous Catalysts over Metal Foam Plate for Steam Reforming of Bio-Ethanol.

Science.gov (United States)

Park, No-Kuk; Jeong, Yong Han; Kang, Misook; Lee, Tae Jin

2018-09-01

The catalytic activity of a macro-mesoporous catalyst coated on a metal foam plate in the reforming of bio-ethanol to synthesis gas was investigated. The catalysts were prepared by coating a support with a noble metal and transition metal. The catalytic activity for the production of synthetic gas by the reforming of bio-ethanol was compared according to the support material, reaction temperature, and steam/carbon ratio. The catalysts coated on the metal foams were prepared using a template method, in which macro-pores and meso-pores were formed by mixing polymer beads. In particular, the thermodynamic equilibrium composition of bio-ethanol reforming with the reaction temperature and steam/carbon ratio to produce synthetic gas was examined using the HSC (Enthalpy-Entropy-Heat capacity) chemistry program in this study. The composition of hydrogen and carbon monoxide in the reformate gas produced by steam reforming over the Rh/Ni-Ce-Zr/Al2O3-based pellet type catalysts and metal foam catalysts that had been coated with the Rh/Al-Ce-Zr-based catalysts was investigated by experimental activity tests. The activity of the metal foam catalyst was higher than that of the pellet type catalyst.

Delta ferrite in the weld metal of reduced activation ferritic martensitic steel

Energy Technology Data Exchange (ETDEWEB)

Sam, Shiju, E-mail: shiju@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat 382 428 (India); Das, C.R.; Ramasubbu, V.; Albert, S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Rajendra Kumar, E. [Institute for Plasma Research, Gandhinagar, Gujarat 382 428 (India)

2014-12-15

Formation of delta(δ)-ferrite in the weld metal, during autogenous bead-on-plate welding of Reduced Activation Ferritic Martensitic (RAFM) steel using Gas Tungsten Arc Welding (GTAW) process, has been studied. Composition of the alloy is such that delta-ferrite is not expected in the alloy; but examination of the weld metal revealed presence of delta-ferrite in the weld metal. Volume fraction of delta-ferrite is found to be higher in the weld interface than in the rest of the fusion zone. Decrease in the volume fraction of delta-ferrite, with an increase in preheat temperature or with an increase in heat input, is observed. Results indicate that the cooling rate experienced during welding affects the volume fraction of delta-ferrite retained in the weld metal and variation in the delta-ferrite content with cooling rate is explained with variation in the time that the weld metal spends in various temperature regimes in which delta-ferrite is stable for the alloy during its cooling from the liquid metal to the ambient temperature. This manuscript will discuss the effect of welding parameters on formation of delta-ferrite and its retention in the weld metal of RAFM steel.

Current Status of Trace Metal Pollution in Soils Affected by Industrial Activities

Science.gov (United States)

Kabir, Ehsanul; Ray, Sharmila; Kim, Ki-Hyun; Yoon, Hye-On; Jeon, Eui-Chan; Kim, Yoon Shin; Cho, Yong-Sung; Yun, Seong-Taek; Brown, Richard J. C.

2012-01-01

There is a growing public concern over the potential accumulation of heavy metals in soil, owing to rapid industrial development. In an effort to describe the status of the pollutions of soil by industrial activities, relevant data sets reported by many studies were surveyed and reviewed. The results of our analysis indicate that soils were polluted most significantly by metals such as lead, zinc, copper, and cadmium. If the dominant species are evaluated by the highest mean concentration observed for different industry types, the results were grouped into Pb, Zn, Ni, Cu, Fe, and As in smelting and metal production industries, Mn and Cd in the textile industry, and Cr in the leather industry. In most cases, metal levels in the studied areas were found to exceed the common regulation guideline levels enforced by many countries. The geoaccumulation index (I geo), calculated to estimate the enrichment of metal concentrations in soil, showed that the level of metal pollution in most surveyed areas is significant, especially for Pb and Cd. It is thus important to keep systematic and continuous monitoring of heavy metals and their derivatives to manage and suppress such pollution. PMID:22645468

Current Status of Trace Metal Pollution in Soils Affected by Industrial Activities

Directory of Open Access Journals (Sweden)

Ehsanul Kabir

2012-01-01

Full Text Available There is a growing public concern over the potential accumulation of heavy metals in soil, owing to rapid industrial development. In an effort to describe the status of the pollutions of soil by industrial activities, relevant data sets reported by many studies were surveyed and reviewed. The results of our analysis indicate that soils were polluted most significantly by metals such as lead, zinc, copper, and cadmium. If the dominant species are evaluated by the highest mean concentration observed for different industry types, the results were grouped into Pb, Zn, Ni, Cu, Fe, and As in smelting and metal production industries, Mn and Cd in the textile industry, and Cr in the leather industry. In most cases, metal levels in the studied areas were found to exceed the common regulation guideline levels enforced by many countries. The geoaccumulation index (Igeo, calculated to estimate the enrichment of metal concentrations in soil, showed that the level of metal pollution in most surveyed areas is significant, especially for Pb and Cd. It is thus important to keep systematic and continuous monitoring of heavy metals and their derivatives to manage and suppress such pollution.

Effects of preparation method and active metal content on of Ni/kieselguhr catalyst activity

International Nuclear Information System (INIS)

Galuh Widiyarti; Wuryaningsih Sri Rahayu

2010-01-01

The preparation and the active metal content influence the activity of catalyst. Study has been conducted to see the activity of Ni/kieselguhr based on preparation method and Nickel (Ni) contents in the catalyst in the laboratory scale. The Ni/kieselguhr catalyst were prepared by impregnation and precipitation methods, with Ni active contents of 10, 20, and 30 % by weight. The catalysts characterization was analyzed using X-Ray Diffraction (XRD). Catalysts activities were analyzed based on decreasing of iodine number from hydrogenation of crude palm oil for 2 hours. The activity tests results show that precipitation catalysts are more active than impregnation catalysts. The decreasing in iodine number of fatty acid after 2 hours of hydrogenation process using precipitation catalysts and impregnation catalysts are 51.53 and 21.85 %, respectively. In addition, the catalysts are more active with increasing Ni contents. (author)

Underground Corrosion of Activated Metals in an Arid Vadose Zone Environment

International Nuclear Information System (INIS)

Adler Flitton, M.K; Mizia, R.E.; Bishop, C.W.

2001-01-01

The subsurface radioactive disposal site located at the Idaho National Engineering and Environmental Laboratory contains neutron-activated metals from nonfuel nuclear-reactor- core components. A long-term corrosion test is being conducted to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements in an arid vadose zone environment. The tests use nonradioactive metal coupons representing the prominent neutron-activated material buried at the disposal location, namely, Type 304L stainless steel, Type 315L stainless steel, nickel-chromium alloy (UNS NO7718), beryllium, aluminum 6061-T6, and a zirconium alloy, (UNS R60804). In addition, carbon steel (the material presently used in the cask disposal liners and other disposal containers) and a duplex stainless steel (UNS S32550) (the proposed material for the high- integrity disposal containers) are also included in the test program. This paper briefly describes the test program and presents the early corrosion rate results after 1 year and 3 years of underground exposure

Effect of cerium on structure modifications of a hybrid sol–gel coating, its mechanical properties and anti-corrosion behavior

International Nuclear Information System (INIS)

Cambon, Jean-Baptiste; Esteban, Julien; Ansart, Florence; Bonino, Jean-Pierre; Turq, Viviane; Santagneli, S.H.; Santilli, C.V.; Pulcinelli, S.H.

2012-01-01

Highlights: ► New sol–gel routes to replace chromates for corrosion protection of aluminum. ► Effect of cerium concentration on the microstructure of xerogel. ► Electrochemical and mechanical performances of hybrid coating with different cerium contents. ► Good correlation between the different results with an optimal cerium content of 0.01 M. -- Abstract: An organic–inorganic hybrid coating was developed to improve the corrosion resistance of the aluminum alloy AA 2024-T3. Organic and inorganic coatings derived from glycidoxypropyl-trimethoxysilane (GPTMS) and aluminum tri-sec-butoxide Al(O s Bu) 3 , with different cerium contents, were deposited onto aluminum by dip-coating process. Corrosion resistance and mechanical properties were investigated by electrochemical impedance measurements and nano-indentation respectively. An optimal cerium concentration of 0.01 M was evidenced. To correlate and explain the hybrid coating performances in relation to the cerium content, NMR experiments were performed. It has been shown that when the cerium concentration in the hybrid is higher than 0.01 M there are important modifications in the hybrid structure that account for the mechanical properties and anti-corrosion behavior of the sol–gel coating.

Semiquantitative activation analysis in metallic alloys submitted to irregular irradiation

International Nuclear Information System (INIS)

Veissid, N.; Lucki, G.

1979-01-01

An analytic semiquantitative method using neutron activation was developed to determine the impurities and verify the composition of metallic alloys. By the radioactive transformation law, the number of atoms of each element present in the sample is determined measuring the activity in a multichannel. Two samples were analysed: a) Sample of nominal compositions FeNiCr (49,95-49,95 - 0,1% at). b) Sample of nominal composition NiCr (80,20% at). (Author) [pt

A metal-based inhibitor of NEDD8-activating enzyme.

Directory of Open Access Journals (Sweden)

Hai-Jing Zhong

Full Text Available A cyclometallated rhodium(III complex [Rh(ppy(2(dppz](+ (1 (where ppy=2-phenylpyridine and dppz=dipyrido[3,2-a:2',3'-c]phenazine dipyridophenazine has been prepared and identified as an inhibitor of NEDD8-activating enzyme (NAE. The complex inhibited NAE activity in cell-free and cell-based assays, and suppressed the CRL-regulated substrate degradation and NF-κB activation in human cancer cells with potency comparable to known NAE inhibitor MLN4924. Molecular modeling analysis suggested that the overall binding mode of 1 within the binding pocket of the APPBP1/UBA3 heterodimer resembled that for MLN4924. Complex 1 is the first metal complex reported to suppress the NEDDylation pathway via inhibition of the NEDD8-activating enzyme.

Influence of osmotic and metal stresses on nitrogenase activity of ...

African Journals Online (AJOL)

SERVER

2007-08-06

Aug 6, 2007 ... metal requirements often absent in other bacteria; copper ... Table 1. The effect of salt concentrations on nitrogenase activity in nitrogen-fixing Anabaena, Nostoc and Nodularia spp. ... as a detoxification mechanism. ..... the critical iron toxicity contents of paddy are above 500 .... Isolation of nickel dependent.

At the Nexus of Antibiotics and Metals: The Impact of Cu and Zn on Antibiotic Activity and Resistance.

Science.gov (United States)

Poole, Keith

2017-10-01

Environmental influences on antibiotic activity and resistance can wreak havoc with in vivo antibiotic efficacy and, ultimately, antimicrobial chemotherapy. In nature, bacteria encounter a variety of metal ions, particularly copper (Cu) and zinc (Zn), as contaminants in soil and water, as feed additives in agriculture, as clinically-used antimicrobials, and as components of human antibacterial responses. Importantly, there is a growing body of evidence for Cu/Zn driving antibiotic resistance development in metal-exposed bacteria, owing to metal selection of genetic elements harbouring both metal and antibiotic resistance genes, and metal recruitment of antibiotic resistance mechanisms. Many classes of antibiotics also form complexes with metal cations, including Cu and Zn, and this can hinder (or enhance) antibiotic activity. This review highlights the ways in which Cu/Zn influence antibiotic resistance development and antibiotic activity, and in so doing impact in vivo antibiotic efficacy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Corrosion Resistance of Zinc Coatings With Aluminium Additive

Directory of Open Access Journals (Sweden)

Votava Jiří

2014-08-01

Full Text Available This paper is focused on evaluation of anticorrosion protection of inorganic metal coatings such as hot-dipped zinc and zinc-galvanized coatings. The thickness and weight of coatings were tested. Further, the evaluation of ductile characteristics in compliance with the norm ČSN EN ISO 20482 was processed. Based on the scratch tests, there was evaluated undercorrosion in the area of artificially made cut. Corrosion resistance was evaluated in compliance with the norm ČSN EN ISO 9227 (salt-spray test. Based on the results of the anticorrosion test, there can be stated corrosion resistance of each individual protective coating. Tests were processed under laboratory conditions and may vary from tests processed under conditions of normal atmosphere.

Laser ablation and competitive technologies in paint stripping of heavy anticorrosion coatings

Science.gov (United States)

Schuöcker, Georg D.; Bielak, Robert

2007-05-01

During the last years surface preparation prior to coating operations became an important research and development task, since tightened environmental regulations have to be faced in view of the deliberation of hazardous compounds of coatings. Especially, ship-yards get more and more under pressure, because the environmental commitment of their Asian competitors is fairly limited. Therefore, in the US and in Europe several technology evaluation projects have been launched to face this challenge. The majority of coating service providers and ship yards use grit blasting; this process causes heavy emissions as of dust and enormous amounts of waste as polluted sand. Coating removal without any blasting material would reduce the environmental impact. Laser processing offers ecological advantages. Therefore thermal processes like laser ablation have been studied thoroughly in several published projects and also in this study. Many of these studies have been focused on the maintenance of airplanes, but not on de-coating of heavy protective coatings. In this case the required laser power is extra-high. This study is focused on the maintenance of heavy anti-corrosion coatings and compares the industrial requirements and the opportunities of the innovative laser processes. Based on the results of this analysis similar approaches as e.g. plasma jet coating ablation have been studied. It was concluded that none of these methods can compete economically with the conventional processes as grit blasting and water jetting since the required ablation rate is very high (>60m2/h). A new process is required that is not based on any blasting operation and which does not depend strongly on the coating's characteristic. The delamination of the coating where the coatings is not removed by evaporation, but in little pieces of the complete coating system meets these requirements. The delamination can be accomplished by the thermal destruction of the primer coating by an intense heat pulse

Stability and activity of doped transition metal zeolites in the hydrothermal processing

Directory of Open Access Journals (Sweden)

Thomas François Robin

2015-12-01

Full Text Available This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper and iron in under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered as a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds which have an impact on the physical and chemical propriety of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts but their stability and activity under hydrothermal conditions is not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350 °C. Catalysts have been characterised before and after treatment using XRD, BET physisorption and STEM microscopy. Metal leaching was determined by analysis of the water phase following hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5 for example molybdenum improves the crystallinity of the zeolite. In general, metal doped zeolites were relatively stable under subcritical water. Activity of the catalysts for processing lipids, protein and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella and P. ellipsoidea. The catalysts exhibited greater activity towards converting lipids for example MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

Stability and Activity of Doped Transition Metal Zeolites in the Hydrothermal Processing

International Nuclear Information System (INIS)

Robin, Thomas François; Ross, Andrew B.; Lea-Langton, Amanda R.; Jones, Jenny M.

2015-01-01

This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper, and iron under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion-exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds that have an impact on the physical and chemical properties of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts, but their stability and activity under hydrothermal conditions are not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350°C. Catalysts have been characterized before and after treatment using X-ray diffraction, BET physisorption, and scanning transmission electronic microscopy. Metal leaching was determined by the analysis of the water phase following the hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5, for example, molybdenum improves the crystallinity of the zeolite. In general, metal-doped zeolites were relatively stable in subcritical water. The activity of the catalysts for processing lipids, protein, and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella, and Pseudochoricystis ellipsoidea. The catalysts exhibited greater activity toward converting lipids, for example, MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

Stability and Activity of Doped Transition Metal Zeolites in the Hydrothermal Processing

Energy Technology Data Exchange (ETDEWEB)

Robin, Thomas François, E-mail: thomas.cognac@gmail.com; Ross, Andrew B.; Lea-Langton, Amanda R.; Jones, Jenny M. [School of Chemical and Process Engineering, University of Leeds, Leeds (United Kingdom)

2015-12-14

This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper, and iron under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion-exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds that have an impact on the physical and chemical properties of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts, but their stability and activity under hydrothermal conditions are not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350°C. Catalysts have been characterized before and after treatment using X-ray diffraction, BET physisorption, and scanning transmission electronic microscopy. Metal leaching was determined by the analysis of the water phase following the hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5, for example, molybdenum improves the crystallinity of the zeolite. In general, metal-doped zeolites were relatively stable in subcritical water. The activity of the catalysts for processing lipids, protein, and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella, and Pseudochoricystis ellipsoidea. The catalysts exhibited greater activity toward converting lipids, for example, MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

Removal of heavy metals using a microbial active, continuously operated sand filter

International Nuclear Information System (INIS)

Ebner, C.

2001-01-01

Heavy metals play an important role within the spectrum of the various pollutants, emitted into the environment via human activities. In contrast to most organic pollutants, heavy metal can not be degraded. Many soils, lakes and rivers show a high contamination with heavy metals due to the enrichment of these pollutants. In addition to existing chemical-physical and biological technologies for the treatment of heavy metal containing waste waters a demand for new, efficient and low-cost cleaning technologies exists, particularly for high volumes of weakly contaminated waters. Such a technology was developed within the framework of a scientific project of the European Union. The approach makes use of a continuously operated, moving-bed Astrasand filter, which has been operated as a continuous biofilm reactor. By inoculation of the reactor with bacteria providing different, defined mechanisms of metal immobilization, and by continuous supply of suitable nutrients, a metal-immobilizing biofilm is built up and regenerated continuously. Metal-enriched biomass is removed continuously from the system, and the contained metals can be recycled by pyrometallurgical treatment of the biomass. The subjects of the present work were the optimization of the nutrient supply for the process of metal removal, the investigation of the toxicity of different waste waters, the optimization of inoculation and biofilm formation, set-up and operation of a lab scale sand filter and the operation of a pilot scale sand filter treating rinsing water of a chemical nickel plating plant. First, basic parameters like toxicity of heavy metal-containing waste waters and the influence of the nutrition of bacteria on biosorption and total metal removal were examined, using freely suspended bacteria in batch culture. Concerning toxicity great differences could be found within the spectrum of heavy metal-containing waste waters tested. Some waters completely inhibited growth, while others did not

Application of brown coal activated mechanically at disposal of heavy metal from waters

International Nuclear Information System (INIS)

Brezovska, M.

2003-01-01

Sorptive characteristics of activated brown coal from mine of Novaky and impact of mechanical activation on sorption of heavy metals from water were examined. Experimental results indicate suitable choice and good absorption ability of used material

Chalcogenide metal centers for oxygen reduction reaction: Activity and tolerance

International Nuclear Information System (INIS)

Feng Yongjun; Gago, Aldo; Timperman, Laure; Alonso-Vante, Nicolas

2011-01-01

This mini-review summarizes materials design methods, oxygen reduction kinetics, tolerance to small organic molecules and fuel cell performance of chalcogenide metal catalysts, particularly, ruthenium (Ru x Se y ) and non-precious transition metals (M x X y : M = Co, Fe and Ni; X = Se and S). These non-platinum catalysts are potential alternatives to Pt-based catalysts because of their comparable catalytic activity (Ru x Se y ), low cost, high abundance and, in particular, a high tolerance to small organic molecules. Developing trends of synthesis methods, mechanism of oxygen reduction reaction and applications in direct alcohol fuel cells as well as the substrate effect are highlighted.

Epoxy coatings for anticorrosion challenges: a link between chemistry and performance?

Energy Technology Data Exchange (ETDEWEB)

Sauvant-Moynot, Valerie; Schweitzer, Sylvie; Grenier, Jacky; Duval, Sebastien [Institut Francais du Petrole, 1 et 4 avenue Bois Preau, 92450 Rueil-Malmaison (France)

2004-07-01

Epoxy coatings have been used extensively for pipeline protection in the oil and gas industries over the past decades. Thank to their outstanding adhesive properties, epoxy resins are classically used for external coating of offshore pipelines although cathodic protection is applied. They provide corrosion protection while being used as neat coating or as primer layer in a three-layer coating. Protection of internal pipelines devoted to gas transport is another application of epoxy coatings. Whatever the case, the choice of the right epoxy formulation should be adapted to the service conditions, namely exposition medium and temperature, in order to provide efficient and sustainable corrosion protection. Epoxy resins constitute a wide family and classical formulations may not fulfill the requirements of today's challenges: as pipelines are require d to operate in more and more difficult conditions, coatings are expected to function in higher temperature conditions; additionally, practical conditions such as temporary injection of methanol make the environmental exposure of the epoxy coating harsher. Therefore, there is a need of a better knowledge of technical performance and limitations of high temperature epoxy resins. This paper examined the influence of the epoxy network architecture on their protection properties and durability while exposed to distilled / sea water at 110 deg. C and to methanol at room temperature. The objective was to investigate the link between resin chemistry and final performance with respect to anticorrosion applications. Five epoxy resin formulations mixed in stoichiometric proportions were cured and post-cured to infinite extent in order to achieve densely cross-linked networks exhibiting controlled and reproducible architectures. Gravimetric and pressurised differential scanning calorimetry (DSC) measurements were performed to evaluate the plasticization effect of both water and methanol on formulations under study. The related

The effects of addition of poly(vinyl) alcohol (PVA) as a green corrosion inhibitor to the phosphate conversion coating on the anticorrosion and adhesion properties of the epoxy coating on the steel substrate

Energy Technology Data Exchange (ETDEWEB)

Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir; Vakili, H.; Amini, R.

2015-02-01

Highlights: • Room temperature zinc phosphate coating was applied on the surface of steel sample. • Poly(vinyl) alcohol was added to the phosphating bath as a green corrosion inhibitor. • The adhesion and anticorrosion properties of the epoxy coating were investigated. • PVA decreased the phosphate crystal size and porosity. • PVA enhanced the corrosion protection and adhesion properties of the epoxy coating. - Abstract: Steel substrates were chemically treated by room temperature zinc phosphate conversion coating. Poly(vinyl) alcohol (PVA) was added to the phosphate solution as a green corrosion inhibitor. Finally, the epoxy/polyamide coating was applied on the untreated and surface treated steel samples. The effects of PVA on the morphological properties of the phosphate coating were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle measuring device. The adhesion properties of the epoxy coatings applied on the surface treated samples were investigated by pull-off and cathodic delamination tests. Also, the anticorrosion properties of the epoxy coatings were studied by electrochemical impedance spectroscopy (EIS). Results showed that addition of PVA to the phosphate coating increased the population density of the phosphate crystals and decreased the phosphate grain size. The contact angle of the steel surface treated by Zn-PVA was lower than Zn treated one. The corrosion resistance of the epoxy coating was considerably increased on the steel substrate treated by zinc phosphate conversion coating containing PVA. PVA also enhanced the adhesion properties of the epoxy coating to the steel surface and decreased the cathodic delamination significantly.

Change of heavy metal speciation, mobility, bioavailability, and ecological risk during potassium ferrate treatment of waste-activated sludge.

Science.gov (United States)

Yu, Ming; Zhang, Jian; Tian, Yu

2018-05-01

The effects of potassium ferrate treatment on the heavy metal concentrations, speciation, mobility, bioavailability, and environmental risk in waste-activated sludge (WAS) at various dosages of potassium ferrate and different treatment times were investigated. Results showed that the total concentrations of all metals (except Cd) were decreased slightly after treatment and the order of metal concentrations in WAS and treated waste-activated sludge (TWAS) was Mg > Zn > Cu > Cr > Pb > Ni > Cd. Most heavy metals in WAS remained in TWAS after potassium ferrate treatment with metal residual rates over 67.8% in TWAS. The distribution of metal speciation in WAS was affected by potassium ferrate treatment. The bioavailability and the mobility of heavy metals (except Mg) in TWAS were mitigated, compared to those in WAS. Meanwhile, the environmental risk of heavy metals (except Pb and Cu) was alleviated after potassium ferrate treatment.

Changes in the biological activity of heavy metal- and oil-polluted soils in urban recreation territories

Science.gov (United States)

Trifonova, T. A.; Zabelina, O. N.

2017-04-01

Urban recreation areas of different sizes were investigated in the city of Vladimir. The degree of their contamination with heavy metals and oil products was revealed. The content of heavy metals exceeded their maximum permissible concentrations by more than 2.5 times. The total content of heavy metals decreased in the sequence: Zn > Pb > Co > Mn > Cr > Ni. The mass fraction of oil products in the studied soils varied within the range of 0.016-0.28 mg/g. The reaction of soils in public gardens and a boulevard was neutral or close to neutral; in some soil samples, it was weakly alkaline. The top layer of all the soils significantly differed from the lower one by the higher alkalinity promoting the deposition of heavy metals there. As the content of Ni, Co, and Mn increased and exceeded the background concentrations, but did not reach the three-fold value of the maximum permissible concentrations, the activity of catalase was intensified. The stimulating effect of nickel on the catalase activity was mostly pronounced at the neutral soil reaction. The urease activity increased when heavy metals and oil products were present together in the concentrations above the background ones, but not higher than the three-fold maximal permissible concentrations for heavy metals and 0.3 mg/g for the content of oil products. The nitrifying activity was inhibited by oil hydrocarbons that were recorded in the soils in different amounts.

In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films

Directory of Open Access Journals (Sweden)

Junsheng Wu

2017-04-01

Full Text Available A layered double hydroxide (LDH film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM. The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS, scanning electrochemical microscopy (SECM, and a salt-spray test (SST.The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film.

Heavy metals contamination characteristics in soil of different mining activity zones

Institute of Scientific and Technical Information of China (English)

LIAO Guo-li; LIAO Da-xue; LI Quan-ming

2008-01-01

Depending upon the polluted features of various mining activities in a typical nonferrous metal mine, the contaminated soil area was divided into four zones which were polluted by tailings, mine drainage, dust deposition in wind and spreading minerals during vehicle transportation, respectively. In each zone, soil samples were collected. Total 28 soil samples were dug and analyzed by ICP-AES and other relevant methods. The results indicate that the average contents of Zn, Pb, Cd, Cu and As in soils are 508.6, 384.8, 7.53, 356 and 44.6 mg/kg, respectively. But the contents of heavy metals in different zone have distinct differences. The proportion of oxidizing association with organic substance is small. Difference of the association of heavy metals is small in different polluted zones.

Active method of neutron time correlation coincidence measurement to authenticate mass and enrichment of uranium metal

International Nuclear Information System (INIS)

Zhang Songbai; Wu Jun; Zhu Jianyu; Tian Dongfeng; Xie Dong

2011-01-01

The active methodology of time correlation coincidence measurement of neutron is an effective verification means to authenticate uranium metal. A collimated 252 Cf neutron source was used to investigate mass and enrichment of uranium metal through the neutron transport simulation for different enrichments and different masses of uranium metal, then time correlation coincidence counts of them were obtained. By analyzing the characteristic of time correlation coincidence counts, the monotone relationships were founded between FWTH of time correlation coincidence and multiplication factor, between the total coincidence counts in FWTH for time correlation coincidence and mass of 235 U multiplied by multiplication factor, and between the ratio of neutron source penetration and mass of uranium metal. Thus the methodology to authenticate mass and enrichment of uranium metal was established with time correlation coincidence by active neutron investigation. (authors)

Synthesis, characterization, and controlled release anticorrosion behavior of benzoate intercalated Zn-Al layered double hydroxides

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi [Shandong Provincial Key Lab of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Zhang, Dun, E-mail: zhangdun@qdio.ac.cn [Shandong Provincial Key Lab of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)

2011-11-15

Graphical abstract: The benzoate anion released from Zn-Al LDHs provides a more effective long-term protection against corrosion of Q235 carbon steel in 3.5% NaCl solution. Highlights: {yields} A benzoate anion corrosion inhibitor intercalated Zn-Al layered double hydroxides (LDHs) has been assembled by coprecipitation method. {yields} The kinetic simulation indicates that the ion-exchange one is responsible for the release process and the diffusion through particle is the rate limiting step. {yields} A significant reduction of the corrosion rate is observed when the LDH nanohybrid is present in the corrosive media. -- Abstract: Corrosion inhibitor-inorganic clay composite including benzoate anion intercalated Zn-Al layered double hydroxides (LDHs) are assembled by coprecipitation. Powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectrum analyses indicate that the benzoate anion is successfully intercalated into the LDH interlayer and the benzene planes are vertically bilayer-positioned as a quasi-guest ion-pair form in the gallery space. Kinetic simulation for the release data, XRD and FT-IR analyses of samples recovered from the release medium indicate that ion-exchange is responsible for the release process and diffusion through the particle is also indicated to be the rate-limiting step. The anticorrosion capabilities of LDHs loaded with corrosion inhibitor toward Q235 carbon steel are analyzed by polarization curve and electrochemical impedance spectroscopy methods. Significant reduction of corrosion rate is observed when the LDH nanohybrid is present in the corrosive medium. This hybrid material may potentially be applied as a nanocontainer in self-healing coatings.

Application of a mixed metal oxide catalyst to a metallic substrate

Science.gov (United States)

Sevener, Kathleen M. (Inventor); Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Wisner, Daniel L. (Inventor)

2009-01-01

A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

EFFECT OF HEAVY METAL IONS ON THE NUMBER AND ACTIVITY OF Azotobacter AND MELANINSYNTHESIZING MICROMYCETES

Directory of Open Access Journals (Sweden)

Malynovska I. M.

2017-06-01

Full Text Available The aim of the work was to determine the possibility of using the number and activity of Azotobacter cells and melanin-synthesizing micromycetes as indicators of gray forest soils of different types (fallow, extensive and intensive agrosoil pollution with heavy metal ions. For this purpose, there were used laboratory-analytical, microbiological and statistical methods. As a result of research of increasing doses of heavy metals (zinc + lead influence on the number of microorganisms in the gray forest soils it was found that the number and activity of Azotobacter and the number and part of melanin-synthesizing micromycetes in their total number may be fit into indicators of pollution with heavy metals. Azotobacter cells activity index may be considered indicative at contamination levels of 5-100 of maximum permissible concentration in the absence of vegetation, at contamination levels of 10–100 – for soils with phytocenosis. The number and proportion of melaninsynthesizing micromycetes in total guantity may serve as diagnostic sign of gray forest soils pollution with high doses of heavy metals, but only for the period of contamination up to 2 years. It was shown that nature of the effect of heavy metals on the number of microorganisms of indicative groups depended on the presence of plants in the monitoring system, on doses of heavy metals, on the term of contamination and on the type of soil usage.

Impacts of human activity modes and climate on heavy metal "spread" in groundwater are biased.

Science.gov (United States)

Chen, Ming; Qin, Xiaosheng; Zeng, Guangming; Li, Jian

2016-06-01

Groundwater quality deterioration has attracted world-wide concerns due to its importance for human water supply. Although more and more studies have shown that human activities and climate are changing the groundwater status, an investigation on how different groundwater heavy metals respond to human activity modes (e.g. mining, waste disposal, agriculture, sewage effluent and complex activity) in a varying climate has been lacking. Here, for each of six heavy metals (i.e. Fe, Zn, Mn, Pb, Cd and Cu) in groundwater, we use >330 data points together with mixed-effect models to indicate that (i) human activity modes significantly influence the Cu and Mn but not Zn, Fe, Pb and Cd levels, and (ii) annual mean temperature (AMT) only significantly influences Cu and Pb levels, while annual precipitation (AP) only significantly affects Fe, Cu and Mn levels. Given these differences, we suggest that the impacts of human activity modes and climate on heavy metal "spread" in groundwater are biased. Copyright © 2016 Elsevier Ltd. All rights reserved.

Engineering of bone fixation metal implants biointerface-Application of parylene C as versatile protective coating

Energy Technology Data Exchange (ETDEWEB)

Cieslik, Monika, E-mail: cieslik@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Institute of Metallurgy and Materials Science, PAS, W. Reymonta 25, 30-059 Krakow (Poland); Zimowski, Slawomir [AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Golda, Monika [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Institute of Metallurgy and Materials Science, PAS, W. Reymonta 25, 30-059 Krakow (Poland); Engvall, Klas [KTH Royal Institute of Technology, Department of Chemical Engineering and Technology, Division of Chemical Technology, Drottning Kristinas vaeg. 42, SE-100 44 Stockholm (Sweden); Pan, Jinshan [KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas vaeg. 51, SE-100 44 Stockholm (Sweden); Rakowski, Wieslaw [AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Kotarba, Andrzej, E-mail: kotarba@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland)

2012-12-01

The tribological and protective properties of parylene C coatings (2-20 {mu}m) on stainless steel 316L implant materials were investigated by means of electrochemical measurements and wear tests. The thickness and morphology of the CVD prepared coatings were characterized by scanning electron and laser confocal microscopy. The stability of the coatings was examined in contact with Hanks' solution and H{sub 2}O{sub 2} (simulating the inflammatory response). It was concluded that silane-parylene C coating with the optimum thickness of 8 {mu}m exhibits excellent wear resistance properties and limits the wear formation. The engineered versatile coating demonstrates sufficient elastomer properties, essential to sustain the implantation surgery strains and micromotions during long-term usage in the body. - Highlights: Black-Right-Pointing-Pointer A versatile coating for protection of metal implant surface is proposed. Black-Right-Pointing-Pointer The protective properties of 2-20 {mu}m silane-parylene C coating were examined. Black-Right-Pointing-Pointer The engineered material proves its high anticorrosive and wear resistance. Black-Right-Pointing-Pointer The practical implications of the coating properties were discussed.

Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents.

Science.gov (United States)

Bendell, L I

2011-02-15

Archived samples of blue grouse (Dendragapus obscurus) gizzard contents, inclusive of grit, collected yearly between 1959 and 1970 were analyzed for cadmium, lead, zinc, and copper content. Approximately halfway through the 12-year sampling period, an open-pit copper mine began activities, then ceased operations 2 years later. Thus the archived samples provided a unique opportunity to determine if avian gizzard contents, inclusive of grit, could reveal patterns in the anthropogenic deposition of trace metals associated with mining activities. Gizzard concentrations of cadmium and copper strongly coincided with the onset of opening and the closing of the pit mining activity. Gizzard zinc and lead demonstrated significant among year variation; however, maximum concentrations did not correlate to mining activity. The archived gizzard contents did provide a useful tool for documenting trends in metal depositional patterns related to an anthropogenic activity. Further, blue grouse ingesting grit particles during the time of active mining activity would have been exposed to toxicologically significant levels of cadmium. Gizzard lead concentrations were also of toxicological significance but not related to mining activity. This type of "pulse" toxic metal exposure as a consequence of open-pit mining activity would not necessarily have been revealed through a "snap-shot" of soil, plant or avian tissue trace metal analysis post-mining activity. Copyright © 2010 Elsevier B.V. All rights reserved.

Pharmacological and biological activities of Mirabilis jalapa L.

Directory of Open Access Journals (Sweden)

Rozina Rozina

2016-05-01

Full Text Available AbstractPlants have been used for health care and medical purposes for several thousands of years. The number of higher plant species on earth is about 250000. It is estimated that 35000 to 70000 species have, at one time or another, been used in some cultures for medicinal purposes. One of these is Mirabilis jalapa L. which is traditionally used as Purgative and emetic, for treatment of many gastrointestinal disorders, including dysentery, diarrhea, muscle pain and abdominal colic. Besides this it also exhibits certain useful activities like Antiviral activity, Antimicrobial activity, Antimalarial activity, Anthelmintic activity, Antioxidant activity, Aytotoxic activity Anti-tubercular drugs induced hepatotoxicity, Antinociceptive activity, Antifungal activity, Anti-corrosion activity, Antispasmodic activity, Anti-inflammatory activity and many others. Pharmacologically active compounds include active alcoholic extract, ether compound-3,3’-Methylenebis (4- hydroxycoumarin N-D-alpha-Phenylyglycinelaminaribiitol-3-(4-(dimethylamino cinnamoyl 4hydroxycoumarin. The purpose of my review is to find out the areas of scope and to give the detail of the work done on Mirabilis Jalapa L. for future research work.

TSCA Chemical Data Reporting Fact Sheet: Reporting Manufactured Chemical Substances from Metal Mining and Related Activities

Science.gov (United States)

This fact sheet provides guidance on the Chemical Data Reporting (CDR) rule requirements related to the reporting of mined metals, intermediates, and byproducts manufactured during metal mining and related activities.

Metallic Concentration in Karnaphuly Estuary Sediment Using Neutron Activation Analysis Technique

International Nuclear Information System (INIS)

Rahman, A.K.M.R.; Chakroborty, S.R.; Roy, P.K.; Dev, A.K.

2013-01-01

Thousands of tonnes of liquid waste, dirt and garbage from different mills and factories from Kaptai to Chittagong are dumped unhindered into the Karnaphuli River. Pollutants enter the river directly from urban sewerage and industrial waste discharges. Ships pollute waterways in many ways. All theses can contribute to the heavy and other metals of the water bodies. To find out concentration of different metallic elements and make a comparison with the world reference values twenty one surface sediment samples were collected from the different locations of Karnaphuly River near Chittagong city drainage outlet. Neutron Activation Analysis (NAA) technique was used for detecting the concentration qualitatively and quantitatively using the 3 MW TRIGA MARK II research reactor of Atomic Energy Research Establishment, Savar, Dhaka. Pearson correlation among the elements obtained using SPSS software. Three transitional metals Fe, Cr and Co, two alkali metals Rb and Na, two lanthanides La and Ce, and two metalloids As and Sb were determined. The concentrations of elements were compared with the world reference values. Some elements are found in elevated level. (author)

Effects of metal-ion replacement on pyrazinamidase activity: A quantum mechanical study.

Science.gov (United States)

Khadem-Maaref, Mahmoud; Mehrnejad, Faramarz; Phirouznia, Arash

2017-05-01

Pyrazinamidase (PZase), a metalloenzyme, is responsible for acidic modification of pyrazinamide (PZA), a drug used in tuberculosis treatment. The metal coordination site of the enzyme is able to coordinate various divalent metal cofactors. Previous experimental studies have demonstrated that metal ions, such as Co 2+ , Mn 2+ , and Zn 2+ , are able to reactivate metal-depleted PZase, while others including Cu 2+ , Fe 2+ , and Mg 2+ , cannot restore activity. In this study, we investigated binding of various metal ions to the metal coordination site (MCS) of the enzyme using quantum mechanical calculations. We calculated the metal-ligand (residue) binding energy and the atomic partial charges in the presence of various ions. The results indicated that the tendency of alkaline earth metals to bind to PZase MCS is very low and not suitable for enzyme structural and catalytic function. In contrast, Co 2+ and Ni 2+ ions have very high binding affinity and are favorable to the structural and functional properties of the enzyme. Furthermore, we observed that the rate at which Ni 2+ , Co 2+ and Fe 2+ ions in PZase MCS polarize the OH bond of coordinated water molecules is much higher than the polarization rate created by other ions. This finding suggests that the coordination of Ni 2+ , Co 2+ , or Fe 2+ to PZase facilitates the deprotonation of coordinated water molecules to generate a nucleophile that catalyzes the enzymatic reaction. Copyright © 2017 Elsevier Inc. All rights reserved.

Deposition of SiOx on Metal Surface with a DBD Plasma Gun at Atmospheric Pressure for Corrosion Prevention

International Nuclear Information System (INIS)

Han Erli; Chen Qiang; Zhang Yuefei; Chen Fei; Ge Yuanjing

2007-01-01

In this study, SiO x films were deposited by a dielectric barrier discharge (DBD) plasma gun at an atmospheric pressure. The relationship of the film structures with plasma powers was investigated by Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). It was shown that an uniform and cross-linking structure film was formed by the DBD gun. As an application, the SiO x films were deposited on a carbon steel surface for the anti-corrosion purpose. The experiment was carried out in a 0.1 M NaCl solution. It was found that a very good anti-corrosive property was obtained, i.e., the corrosion rate was decreased c.a. 15 times in 5% NaCl solution compared to the non-SiO x coated steel, as detected by the potentiodynamic polarization measurement

Fiscal 1999 report on results of R and D of industrial science and technology that creates new industry. Development of super metal technology (development of technology for innovative metallic material); 1999 nendo super metal no gijutsu kaihatsu seika hokokusho. Kakushinteki kinzoku sokei zairyo no gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

With the purpose of obtaining higher strength/toughness and higher anticorrosion in metallic materials, R and D was conducted on technologies for grain refining/dispersing and for amorphous bulk formed bodies, with fiscal 1999 results compiled. In the technological study on grain refinement and dispersion, austenitic stainless steel and 12Cr ferrite steel were used, with creative manufacturing carried out for microcrystallized structure materials by a powder metallurgy method. The result of the study revealed that suppressing grain growth by carbide or oxide was important for grain refinement, and that homogenizing the inside of a material by hot forging after solidification forming was essential for ductility improvement. In the development of the technology for amorphous bulk formed bodies, a laser heating type forming test device was designed and manufactured, with a technique examined in which bulk amorphous of a complex-shaped article was formed through rapid quenching of amorphous alloy powder by laser. This year, a trial production was performed for the laminated solidified bodies of Ni amorphous alloy powder, and the basic data was thereby collected such as feeding of the powder and conditions of the laser irradiation. (NEDO)

Understanding Trends in Catalytic Activity: The Effect of Adsorbate-Adsorbate Interactions for CO Oxidation Over Transition Metals

DEFF Research Database (Denmark)

Grabow, Lars; Larsen, Britt Hvolbæk; Nørskov, Jens Kehlet

2010-01-01

Using high temperature CO oxidation as the example, trends in the reactivity of transition metals are discussed on the basis of density functional theory (DFT) calculations. Volcano type relations between the catalytic rate and adsorption energies of important intermediates are introduced...... and the effect of adsorbate-adsorbate interaction on the trends is discussed. We find that adsorbate-adsorbate interactions significantly increase the activity of strong binding metals (left side of the volcano) but the interactions do not change the relative activity of different metals and have a very small...... influence on the position of the top of the volcano, that is, on which metal is the best catalyst....

SEQUESTERING AGENTS FOR ACTIVE CAPS - REMEDIATION OF METALS AND ORGANICS

Energy Technology Data Exchange (ETDEWEB)

Knox, A; Michael Paller, M; Danny D. Reible, D; Xingmao Ma, X; Ioana G. Petrisor, I

2007-05-10

This research evaluated organoclays, zeolites, phosphates, and a biopolymer as sequestering agents for inorganic and organic contaminants. Batch experiments were conducted to identify amendments and mixtures of amendments for metal and organic contaminants removal and retention. Contaminant removal was evaluated by calculating partitioning coefficients. Metal retention was evaluated by desorption studies in which residue from the removal studies was extracted with 1 M MgCl{sub 2} solution. The results indicated that phosphate amendments, some organoclays, and the biopolymer, chitosan, were very effective sequestering agents for metals in fresh and salt water. Organoclays were very effective sorbents for phenanthrene, pyrene, and benzo(a)pyrene. Partitioning coefficients for the organoclays were 3000-3500 ml g{sup -1} for benzo(a)pyrene, 400-450 ml g{sup -1} for pyrene, and 50-70 ml g{sup -1} for phenanthrene. Remediation of sites with a mixture of contaminants is more difficult than sites with a single contaminant because metals and organic contaminants have different fate and transport mechanisms in sediment and water. Mixtures of amendments (e.g., organoclay and rock phosphate) have high potential for remediating both organic and inorganic contaminants under a broad range of environmental conditions, and have promise as components in active caps for sediment remediation.

Environment influence on the solidity of the adhesive joint

Directory of Open Access Journals (Sweden)

Vladimír Válek

2006-01-01

Full Text Available In this paper “Environment influence on the solidity of the adhesive joint” I have dealt with the utilization of the bonding metals and practising experimental laboratory tests of adhesive joints depending on different laboratory environments and anticorrosive protection of the samples.For this laboratory tests I have chosen a universal adhesive. It is a two-component epoxy adhesive with suitable conditions for bonding metals. The samples were made from steel and were produced by the standard ČSN EN 1465. After the bonding and the cure procedure the samples were exposed in H20 environment for exact intervals (parts of the samples were painted by anticorrosive painting. After the exposition I have examinated the solidity of the adhesive joint in shearing stress on the measuring instrument Zwick 050. The samples were compared with etalon that were exposed to no environment.Results of the particular measuring were described into the graphs and were recorded the break down maximum force. When the samples were broken down I have taken a photo of it, which is in the appendix.

Mycoextraction by Clitocybe maxima combined with metal immobilization by biochar and activated carbon in an aged soil.

Science.gov (United States)

Wu, Bin; Cheng, Guanglei; Jiao, Kai; Shi, Wenjin; Wang, Can; Xu, Heng

2016-08-15

To develop an eco-friendly and efficient route to remediate soil highly polluted with heavy metals, the idea of mycoextraction combined with metal immobilization by carbonaceous sorbents (biochar and activated carbon) was investigated in this study. Results showed that the application of carbonaceous amendments decreased acid soluble Cd and Cu by 5.13-14.06% and 26.86-49.58%, respectively, whereas the reducible and oxidizable fractions increased significantly as the amount of carbonaceous amendments added increased. The biological activities (microbial biomass, soil enzyme activities) for treatments with carbonaceous sorbents were higher than those of samples without carbonaceous amendments. Clitocybe maxima (C. maxima) simultaneously increased soil enzyme activities and the total number of microbes. Biochar and activated carbon both showed a positive effect on C. maxima growth and metal accumulation. The mycoextraction efficiency of Cd and Cu in treatments with carbonaceous amendments enhanced by 25.64-153.85% and 15.18-107.22%, respectively, in response to that in non-treated soil, which showed positive correlation to the augment of biochar and activated carbon in soil. Therefore, this work suggested the effectiveness of mycoextraction by C. maxima combined the application of biochar and activated carbon in immobilising heavy metal in contaminated soil. Copyright © 2016. Published by Elsevier B.V.

Haematology, genotoxicity, enzymatic activity and histopathology as biomarkers of metal pollution in the shrew Crocidura russula

International Nuclear Information System (INIS)

Sanchez-Chardi, A.; Marques, C.C.; Gabriel, S.I.; Capela-Silva, F.; Cabrita, A.S.; Lopez-Fuster, M.J.; Nadal, J.; Mathias, M.L.

2008-01-01

Haematological (WBC, RBC, Hgb and Hct) and genotoxicity (MNT) parameters, hepatic enzymatic activities (GST, GPx and GR), and a histopathological evaluation of liver, kidneys and gonads were assessed as general biomarkers of metal pollution in the shrew Crocidura russula inhabiting a pyrite mining area. Specimens exposed to metals presented a few significant alterations when compared with reference animals: GST activity decreased; micronuclei increased; and evident liver alterations related to metal exposure were observed. On the basis of all the parameters studied, age was an important factor that partly explained the observed variation, whereas sex was the least important factor. Significant correlations were also found between heavy metal concentrations and biomarkers evaluated, demonstrating the great influence of these metals in the metabolic alterations. To the best of our knowledge, these data constitute the first measurements of a battery of biomarkers in shrews from a mine site and are among the few available for insectivorous mammals. - Metals from an abandoned pyrite mine produce alterations in haematological parameters, GST, MNT, and histopathology in shrews

Accumulation of Long-lived activity in heavy metal liquid targets

International Nuclear Information System (INIS)

Shubin, Y. N.; Gai, E. V.; Ignatyuk, A. V.; Lunev, V. P.

1997-01-01

The calculations and analysis of the accumulation of radioactive nuclei and long-lived activity in heavy metal liquid targets were performed. The dominating contributions to the total radioactivity of radionuclides resulting from fission, spallation reactions and radiative capture by target nuclei for various irradiation and cooling times were calculated and analyzed. The most important parts of neutron and proton spectra were determined that give the dominant contributions to the total and partial activity of the targets. The contributions of fission products to the target activity and partial activities of main long-lived fission products were evaluated. The results of the calculations are compared with the data on Energy Amplifier Project. (Author) 12 refs

Comparison of soil heavy metal pollution caused by e-waste recycling activities and traditional industrial operations.

Science.gov (United States)

He, Kailing; Sun, Zehang; Hu, Yuanan; Zeng, Xiangying; Yu, Zhiqiang; Cheng, Hefa

2017-04-01

The traditional industrial operations are well recognized as an important source of heavy metal pollution, while that caused by the e-waste recycling activities, which have sprouted in some developing countries, is often overlooked. This study was carried out to compare the status of soil heavy metal pollution caused by the traditional industrial operations and the e-waste recycling activities in the Pearl River Delta, and assess whether greater attention should be paid to control the pollution arising from e-waste recycling activities. Both the total contents and the chemical fractionation of major heavy metals (As, Cr, Cd, Ni, Pb, Cu, and Zn) in 50 surface soil samples collected from the e-waste recycling areas and 20 soil samples from the traditional industrial zones were determined. The results show that the soils in the e-waste recycling areas were mainly polluted by Cu, Zn, As, and Cd, while Cu, Zn, As, Cd, and Pb were the major heavy metals in the soils from the traditional industrial zones. Statistical analyses consistently show that Cu, Cd, Pb, and Zn in the surface soils from both types of sites were contributed mostly by human activities, while As, Cr, and Ni in the soils were dominated by natural background. No clear distinction was found on the pollution characteristic of heavy metals in the surface soils between the e-waste recycling areas and traditional industrial zones. The potential ecological risk posed by heavy metals in the surface soils from both types of sites, which was dominated by that from Cd, ranged from low to moderate. Given the much shorter development history of e-waste recycling and its largely unregulated nature, significant efforts should be made to crack down on illegal e-waste recycling and strengthen pollution control for related activities.

Mathematical Modeling of Metal Active Gas (MAG) Arc Welding

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

In the present paper, a numerical model for MAG (metal active gas) arc welding of thin plate has been developed. In MAG arc welding, the electrode wire is melted and supplied into the molten pool intermittently. Accordingly, it is assumed on the modeling that the thermal energy enters the base-plates through two following mechanisms, i.e., direct heating from arc plasma and “indirect” heating from the deposited metal. In the second part of the paper, MAG arc welding process is numerically analyzed by using the model, and the calculated weld bead dimension and surface profile have been compared with the experimental MAG welds on steel plate. As the result, it is made clear that the model is capable of predicting the bead profile of thin-plate MAG arc welding , including weld bead with undercutting.

Heavy metal pollution caused by small-scale metal ore mining activities: A case study from a polymetallic mine in South China.

Science.gov (United States)

Sun, Zehang; Xie, Xiande; Wang, Ping; Hu, Yuanan; Cheng, Hefa

2018-05-19

Although metal ore mining activities are well known as an important source of heavy metals, soil pollution caused by small-scale mining activities has long been overlooked. This study investigated the pollution of surface soils in an area surrounding a recently abandoned small-scale polymetallic mining district in Guangdong province of south China. A total of 13 tailing samples, 145 surface soil samples, and 29 water samples were collected, and the concentrations of major heavy metals, including Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb, and Se, were determined. The results show that the tailings contained high levels of heavy metals, with Cu, Zn, As, Cd, and Pb occurring in the ranges of 739-4.15 × 10 3 , 1.81 × 10 3 -5.00 × 10 3 , 118-1.26 × 10 3 , 8.14-57.7, and 1.23 × 10 3 -6.99 × 10 3  mg/kg, respectively. Heavy metals also occurred at high concentrations in the mine drainages (15.4-17.9 mg/L for Cu, 21.1-29.3 mg/L for Zn, 0.553-0.770 mg/L for Cd, and 1.17-2.57 mg/L for Pb), particularly those with pH below 3. The mean contents of Cu, Zn, As, Cd, and Pb in the surface soils of local farmlands were up to 7 times higher than the corresponding background values, and results of multivariate statistical analysis clearly indicate that Cu, Zn, Cd, and Pb were largely contributed by the mining activities. The surface soils from farmlands surrounding the mining district were moderately to seriously polluted, while the potential ecological risk of heavy metal pollution was extremely high. It was estimated that the input fluxes from the mining district to the surrounding farmlands were approximately 17.1, 59.2, 0.311, and 93.8 kg/ha/yr for Cu, Zn, Cd, and Pb, respectively, which probably occurred through transport of fine tailings by wind and runoff, and mine drainage as well. These findings indicate the significant need for proper containment of the mine tailings at small-scale metal ore mines. Copyright © 2018. Published by Elsevier

Amélioration des méthodes de protection anticorrosion des structures métalliques : Sous-sujet : Application des systèmes dits de "maintenance" sur préparation de surface UHP

OpenAIRE

MAIRE, G; CENTRE D'ETUDES TECHNIQUES DE L'EQUIPEMENT NORMANDIE-CENTRE - CETE NORMANDIE-CENTRE; LABORATOIRE REGIONAL DES PONTS ET CHAUSSEES DE BLOIS - CETE NORMANDIE-CENTRE - LRPC BLOIS

2005-01-01

Le problème actuel de l'entretien de la protection anticorrosion des structures métalliques est l'augmentation du coût découlant des contraintes règlementaires récentes sur l'évacuation et le traitement des déchets. Lors d'un chantier d'entretien, le principal poste générateur de déchets est le décapage. Toutes les solutions techniques permettant de diminuer la quantité et/ou la nocivité des déchets de décapage sont donc intéressantes aussi bien du point de vue économique que de celui de la p...

Pollution in the urban soils of Lianyungang, China, evaluated using a pollution index, mobility of heavy metals, and enzymatic activities.

Science.gov (United States)

Li, Yu; Li, Hong-Guan; Liu, Fu-Cheng

2017-01-01

Soil samples from 16 urban sites in Lianyungang, China were collected and analyzed. A pollution index was used to assess the potential ecological risk of heavy metals and a sequential extraction procedure was used to evaluate the relative distribution of Cu, Zn, Pb, Cd, Cr, and As in exchangeable, carbonate, Fe/Mn oxide, organic/sulfide, and residual fractions. The mobility of heavy metals and urease (URE) activity, alkaline phosphatase (ALP) activity, and invertase (INV) activity of soils was determined. The results showed that the average concentrations of Cu, Zn, Pb, Cd, Cr, and As in Lianyungang soils were much higher than those in the coastal city soil background values of Jiangsu and China. Among the five studied regions (utilities, commercial, industrial, tourism, and roadside), the industrial region had the highest metal concentrations demonstrating that land use had a significant impact on the accumulation of heavy metals in Lianyungang soils. Compared to the other metals, Cd showed the highest ecological risk. According to chemical partitioning, Cu was associated with the organic/sulfides and Pb and Zn were mainly in the carbonate and the Fe/Mn oxide phase. The greatest amounts of Cd were found in exchangeable and carbonate fractions, while Cr and As were mainly in the residual fraction. Cd had the highest mobility of all metals, and the order of mobility (highest to lowest) of heavy metals in Lianyungang soils was Cd > Zn > Pb > Cu > As > Cr. Soil urease activity, alkaline phosphatase activity, and invertase activity varied considerably in different pollution degree sites. Soil enzyme activities had the lowest levels in roadside and industrial regions. Across all the soil data in the five regions, the total Cu, Zn, Pb, Cd, Cr, and As level was negatively correlated with urease activity, alkaline phosphatase activity, and invertase activity, but the relationship was not significant. In the industrial region, alkaline phosphatase activity had

Adsorption of Heavy Metals on Biologically Activated Brown Coal Sludge

Directory of Open Access Journals (Sweden)

Mária Praščáková

2005-11-01

Full Text Available Adsorption of cooper (II and zinc (II ions from aqueous solutions on a biologically activated brown coal sludge was investigated. Four families of adsorbents were prepared from the brown coal sludge bya microorganism’s activity. There were used microscopic fungi such as Aspergillus niger, Aspergillus clavatus, Penicillium glabrum and Trichoderma viride. Prepared sorbents were capable of removing Cu (II and Zn (II. The sorption isotherm has been constructed and the specific metal uptake and the maximum capacity of the adsorbent have been determined.

SERS and DFT study of copper surfaces coated with corrosion inhibitor

Directory of Open Access Journals (Sweden)

Maurizio Muniz-Miranda

2014-12-01

Full Text Available Azole derivatives are common inhibitors of copper corrosion due to the chemical adsorption occurring on the metal surface that gives rise to a protective film. In particular, 1,2,4-triazole performs comparable to benzotriazole, which is much more widely used, but is by no means an environmentally friendly agent. In this study, we have analyzed the adsorption of 1,2,4-triazole on copper by taking advantage of the surface-enhanced Raman scattering (SERS effect, which highlights the vibrational features of organic ligand monolayers adhering to rough surfaces of some metals such as gold, silver and copper. To ensure the necessary SERS activation, a roughening procedure was implemented on the copper substrates, resulting in nanoscale surface structures, as evidenced by microscopic investigation. To obtain sufficient information on the molecule–metal interaction and the formation of an anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT approach.

In vitro antiplasmodial activity of PDDS-coated metal oxide nanoparticles against Plasmodium falciparum

Science.gov (United States)

Jacob Inbaneson, Samuel; Ravikumar, Sundaram

2013-06-01

Malaria is the most important parasitic disease, leading to annual death of about one million people and the Plasmodium falciparum develops resistant to well-established antimalarial drugs. The newest antiplasmodial drug from metal oxide nanoparticles helps in addressing this problem. Commercial nanoparticles such as Fe3O4, MgO, ZrO2, Al2O3 and CeO2 coated with PDDS and all the coated and non-coated nanoparticles were screened for antiplasmodial activity against P. falciparum. The Al2O3 nanoparticles (71.42 ± 0.49 μg ml-1) showed minimum level of IC50 value and followed by MgO (72.33 ± 0.37 μg ml-1) and Fe3O4 nanoparticles (77.23 ± 0.42 μg ml-1). The PDDS-Fe3O4 showed minimum level of IC50 value (48.66 ± 0.45 μg ml-1), followed by PDDS-MgO (60.28 ± 0.42 μg ml-1) and PDDS-CeO2 (67.06 ± 0.61 μg ml-1). The PDDS-coated metal oxide nanoparticles showed superior antiplasmodial activity than the non-PDDS-coated metal oxide nanoparticles. Statistical analysis reveals that, significant in vitro antiplasmodial activity ( P activity and it might be used for the development of antiplasmodial drugs.

Synthesis, spectroscopic, biological activity and thermal characterization of ceftazidime with transition metals

Science.gov (United States)

Masoud, Mamdouh S.; Ali, Alaa E.; Elasala, Gehan S.; Kolkaila, Sherif A.

2018-03-01

Synthesis, physicochemical characterization and thermal analysis of ceftazidime complexes with transition metals (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were discussed. It's obtained that ceftazidime act as bidentate ligand. From magnetic measurement and spectral data, octahedral structures were proposed for all complexes except for cobalt, nickel and mercury had tetrahedral structural. Hyper chemistry program confirmed binding sites of ceftazidime. Ceftazidime complexes show higher activity than ceftazidime for some strains. From TG and DTA curves the thermal decomposition mechanisms of ceftazidime and their metal complexes were suggested. The thermal decomposition of the complexes ended with the formation of metal oxides as a final product except in case of Hg complex.

Changes in antioxidant enzyme activities in Eichhornia crassipes (Pontederiaceae) and Pistia stratiotes (Araceae) under heavy metal stress

International Nuclear Information System (INIS)

Odjegba, V. J.; Fasidi, I. O.

2007-01-01

Whole plants of Eichhornia crassipes and Pistia stratiotes were exposed to various concentrations (0,0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 mM) of 8 heavy metals (Ag, Cd, Cr, Cu, Hg, Ni, Pb and Zn) hydroponically for 21 days. Spectrometric assays for the total activity of catalase, peroxidase, and superoxide dismutase in the leaves were studied. At the end of the experimental period, data referred to metal treated plants were compared to data of untreated ones (control). Heavy metals increased the activity of catalase, peroxidase and superoxide dismutase in both species and there was differential inducement among metals. Overall, Zn had the least inducement of antioxidant enzymes in both species while Hg had the highest inducement. The increase in antioxidant enzymes in relation to the control plants was more in E. crassipes than P. stratiotes. The results showed that E. crassipes tolerated higher metal concentrations in a greater number of metals than P. stratiotes. (author)

Magnetic activity at infrared frequencies in structured metallic photonic crystals

International Nuclear Information System (INIS)

O'Brien, S.; Pendry, J.P.

2002-01-01

We derive the effective permeability and permittivity of a nanostructured metallic photonic crystal by analysing the complex reflection and transmission coefficients for slabs of various thicknesses. These quantities were calculated using the transfer matrix method. Our results indicate that these structures could be used to realize a negative effective permeability, at least up to infrared frequencies. The origin of the negative permeability is a resonance due to the internal inductance and capacitance of the structure. We also present an analytic model for the effective permeability of the crystal. The model reveals the importance of the inertial inductance due to the finite mass of the electrons in the metal. We find that this contribution to the inductance has implications for the design of metallic magnetic structures in the optical region of the spectrum. We show that the magnetic activity in the structure is accompanied by the concentration of the incident field energy into very small volumes within the structure. This property will allow us to considerably enhance non-linear effects with minute quantities of material. (author)

RESEARCH OF FRUIT CONSERVES’ CORROSIVE AGGRESSIVENESS

Directory of Open Access Journals (Sweden)

I. Kuznecova

2017-10-01

Full Text Available Corrosion of metal canning containers is one of the obstacles in spreading its application for packing of food. Particularly aggressive to the metal container is fruit canned medium, containing organic acids.The basic material for the production of metal canning container is white tinplate. The main advantage of white tinplate is the tin compounds are harmless to human organism. For this reason, a white badge is used widely, usually used for production of canning containers, packaging beverages. Despite the fact that recently often used containers made of aluminum badge (foil, the basic material for manufacturing metal canning containers is steel white tinplate.Now applied for coating paints and varnishes do not provide anti-corrosion protection of inner surface of metal containers during storage. Preserving of canned fruit quality in metal containers is largely defined corrosion resistance of the containers. This is due to the fact that the metal transition to canned fruit in due courses of corrosion processes is lowering the nutritional value and deterioration taste of the product, and while allocation of hydrogen is accompanied by swelling and destruction of metal containers.We have investigated a number of anti-corrosion coatings based on Fe-Cr and Fe-Sn-Ti of their behavior in aggressive mediums canned fruit. For the purpose of modeling such mediums the solutions of most widespread organic acids were used. The research allowed conclude, that in surface solid solutions Fe-Sn-Ti increase the corrosion resistance of carbon steel in aqueous solutions of malic, citric and tartaric acids. This implies that the surface solid solutions’ formation can significantly improve corrosion resistance in aggressive canning mediums.

Impact of metal binding on the antitumor activity and cellular imaging of a metal chelator cationic imidazopyridine derivative.

Science.gov (United States)

Roy, Mithun; Chakravarthi, Balabhadrapatruni V S K; Jayabaskaran, Chelliah; Karande, Anjali A; Chakravarty, Akhil R

2011-05-14

A new water soluble cationic imidazopyridine species, viz. (1E)-1-((pyridin-2-yl)methyleneamino)-3-(3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2(3H)-yl)propan-2-ol (1), as a metal chelator is prepared as its PF(6) salt and characterized. Compound 1 shows fluorescence at 438 nm on excitation at 342 nm in Tris-HCl buffer giving a fluorescence quantum yield (φ) of 0.105 and a life-time of 5.4 ns. Compound 1, as an avid DNA minor groove binder, shows pUC19 DNA cleavage activity in UV-A light of 365 nm forming singlet oxygen species in a type-II pathway. The photonuclease potential of 1 gets enhanced in the presence of Fe(2+), Cu(2+) or Zn(2+). Compound 1 itself displays anticancer activity in HeLa, HepG2 and Jurkat cells with an enhancement on addition of the metal ions. Photodynamic effect of 1 at 365 nm also gets enhanced in the presence of Fe(2+) and Zn(2+). Fluorescence-based cell cycle analysis shows a significant dead cell population in the sub-G1 phase of the cell cycle suggesting apoptosis via ROS generation. A significant change in the nuclear morphology is observed from Hoechst 33258 and an acridine orange/ethidium bromide (AO/EB) dual nuclear staining suggesting apoptosis in cells when treated with 1 alone or in the presence of the metal ions. Apoptosis is found to be caspase-dependent. Fluorescence imaging to monitor the distribution of 1 in cells shows that 1 in the presence of metal ions accumulates predominantly in the cytoplasm. Enhanced uptake of 1 into the cells within 12 h is observed in the presence of Fe(2+) and Zn(2+).

Effect Of Heavy Metals Stress On Enzyme Activities And Chlorophyll Content Of Pea (Pisum Sativum) And Tomato Plants

International Nuclear Information System (INIS)

Ahmed, B.M.; El Maghrabi, G.; Hashem, M.F.

2013-01-01

The effects of heavy metal stress on the chlorophyll in addition to catalase and peroxidase activities were studied in the leaves and roots of tomato and pea plants. Four groups were studied; the control group and other three groups treated with heavy metals. Group 1HM was treated with 1.0 mg CuSO 4 /l + 0.2 mg CdSO 4 /l + 0.1 mg ZnNO 3 /l every 10 days while in group 5 HM and group 10 HM, the doses were 5 and 10 folds the 1 HM, respectively. Leaves and roots of control and heavy metal-stressed plants were harvested after 10 weeks for chlorophyll determination. The chlorophyll content, especially chlo. b, was significantly decreased with the increase in heavy metals stress in both plants. In leaves of heavy metal-stressed plants, the peroxidase level in different stress levels was increased with increasing stress levels in tomato and pea while catalase was unchanged in leaves of tomato in comparison with the control. The activities of catalase and peroxidase in roots of heavy metal-stressed plants were increased in group 5 HM then decreased in case of group 10 HM. The increase in enzyme activities demonstrated that tomato is more tolerant to heavy metals than pea

Investigation of the electrocatalytic activity for oxygen reduction of sputter deposited mixed metal films

International Nuclear Information System (INIS)

Schumacher, L.C.; Holzheuter, I.B.; Nucara, M.C.; Dignam, M.J.

1989-01-01

Sputter-deposited films of silver with lead, manganese and nickel have been studied as possible oxygen reduction electrocatalysts using cyclic voltammetry, rotating disc studies, steady-state polarization and Auger analysis. In general, the Ag-Pb and Ag-Mn films display superior electrocatalytic activity for O 2 reduction, while the Ag-Ni films' performance is inferior to that of pure Ag. For the Ag-Pb films, which show the highest electrocatalytic activity, the mixed metal films display oxidation-reduction behavior which is not simply a superposition of that of the separate metals, and suggests a mechanism for the improved behavior

Monitoring the solid-state electrochemistry of Cu(2,7-AQDC) (AQDC = anthraquinone dicarboxylate) in a lithium battery: coexistence of metal and ligand redox activities in a metal-organic framework.

Science.gov (United States)

Zhang, Zhongyue; Yoshikawa, Hirofumi; Awaga, Kunio

2014-11-19

By adopting a facile synthetic strategy, we obtained a microporous redox-active metal-organic framework (MOF), namely, Cu(2,7-AQDC) (2,7-H2AQDC = 2,7-anthraquinonedicarboxylic acid) (1), and utilized it as a cathode active material in lithium batteries. With a voltage window of 4.0-1.7 V, both metal clusters and anthraquinone groups in the ligands exhibited reversible redox activity. The valence change of copper cations was clearly evidenced by in situ XANES analysis. By controlling the voltage window of operation, extremely high recyclability of batteries was achieved, suggesting the framework was robust. This MOF is the first example of a porous material showing independent redox activity on both metal cluster nodes and ligand sites.

Influence of metal nanoparticle decorated CNTs on polyurethane based electro active shape memory nanocomposite actuators

International Nuclear Information System (INIS)

Raja, Mohan; Shanmugharaj, A.M.; Ryu, Sung Hun; Subha, J.

2011-01-01

Highlights: → Polyurethane based on pristine and metal (Ag and Cu) nanoparticle decorated CNTs nanocomposites are prepared through melt blending process. → The electrical, mechanical, dynamic mechanical, thermal conductivity and electro active shape memory properties of the PU nanocomposites were investigated. → The influence of metal nanoparticle decorated CNTs showed significant improvement in their all properties to compare to pristine CNTs. → Electro active shape memory studies of the PU/M-CNTs nanocomposites reveal extraordinary recoverability of its shape at lower applied dc voltages. - Abstract: Polymer nanocomposites based on thermoplastic polyurethane (PU) elastomer and metal nanoparticle (Ag and Cu) decorated multiwall carbon nanotubes (M-CNTs) were prepared through melt mixing process and investigated for its mechanical, dynamic mechanical and electro active shape memory properties. Structural characterization and morphological characterization of the PU nanocomposites were done using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Morphological characterization revealed better dispersion of M-CNTs in the polyurethane, which is attributed to the improved interaction between the M-CNTs and polyurethane. Loading of the metal nanoparticle coated carbon nanotubes resulted in the significant improvement on the mechanical properties such as tensile strength of the PU composites in comparison to the pristine carbon nanotubes (P-CNTs). Dynamic mechanical analysis showed that the glass transition temperature (Tg) of the polyurethane increases slightly with increasing loading of both pristine and metal nanoparticle functionalized carbon nanotubes. The metal nanoparticles decorated carbon nanotubes also showed significant improvement in the thermal and electrical conductivity of the PU/M-CNTs nanocomposites. Shape memory studies of the PU/M-CNTs nanocomposites exhibit remarkable recoverability of its shape at lower applied dc voltages.

Physicochemical characteristics and sorption capacities of heavy metal ions of activated carbons derived by activation with different alkyl phosphate triesters

Science.gov (United States)

Wang, Jing; Liu, Hai; Yang, Shaokun; Zhang, Jian; Zhang, Chenglu; Wu, Haiming

2014-10-01

Five alkyl phosphate triesters (APTEs), including trimethyl phosphate (TMP), triethyl phosphate (TEP), triisopropyl phosphate (TPP), tributyl phosphate (TBP) and trioctyl phosphate (TOP), were used as activating agents for preparing activated carbons (AC-APTEs) with high surface acidity and metal ion sorption capacity. N2 adsorption/desorption isotherms, surface morphologies, elemental compositions, results of Boehm's titration and sorption capacities of heavy metal ions of the carbons were investigated. AC-APTEs contained much more acidic groups and exhibited much less surface area (phosphoric acid activation. For the AC-APTEs, AC-TOP had the highest surface area (488 m2/g), AC-TMP showed the highest yield (41.1%), and AC-TBP possessed the highest acidic groups (2.695 mmol/g), oxygen content (47.0%) and metal ion sorption capacities (40.1 mg/g for Ni(II) and 53.5 mg/g for Cd(II)). For the carbons, AC-APTEs showed much larger Ni(II) and Cd(II) sorption capacities than AC-PPA, except AC-TPP. The differences of the carbons in the physicochemical and sorption properties suggested surface chemistry of the carbons was the main factor influencing their sorption capacities whereas the pore structure played a secondary role.

Spectroscopic characterization of metal complexes of novel Schiff base. Synthesis, thermal and biological activity studies

Science.gov (United States)

Omar, M. M.; Mohamed, Gehad G.; Ibrahim, Amr A.

2009-07-01

Novel Schiff base (HL) ligand is prepared via condensation of 4-aminoantipyrine and 2-aminobenzoic acid. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA, DrTGA and DTA). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a uninegatively tridentate manner with NNO donor sites of the azomethine N, amino N and deprotonated caroxylic-O. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ΔH*, ΔS* and ΔG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus Pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Shciff base ligand against one or more bacterial species.

ENHANCEMENT OF ACIDITY AND CATALYTIC ACTIVITY OF ALUMINA BASED METAL ORGANIC FRAMEWORK (MIL-53 Al)

OpenAIRE

Yilmaz, Esra; Sert, Emine; Atalay, Ferhan Sami

2017-01-01

Metal organic frameworks are highly porous materials which are formed bycombination of metal precursor and salts as inorganic part and ligand asorganic part. They have many advantages such as low density, high surface area,tunable pore size and high porosity. Due to peculiar features, such asunsaturated metal active sites, high surface area and easily functionalization,its usage as catalyst are promising.  The MIL-53(Al) structure contains chains of transcorner-sharing [AlO4(OH)2] oc...

Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents

Energy Technology Data Exchange (ETDEWEB)

Bendell, L.I., E-mail: bendell@sfu.ca

2011-02-15

Archived samples of blue grouse (Dendragapus obscurus) gizzard contents, inclusive of grit, collected yearly between 1959 and 1970 were analyzed for cadmium, lead, zinc, and copper content. Approximately halfway through the 12-year sampling period, an open-pit copper mine began activities, then ceased operations 2 years later. Thus the archived samples provided a unique opportunity to determine if avian gizzard contents, inclusive of grit, could reveal patterns in the anthropogenic deposition of trace metals associated with mining activities. Gizzard concentrations of cadmium and copper strongly coincided with the onset of opening and the closing of the pit mining activity. Gizzard zinc and lead demonstrated significant among year variation; however, maximum concentrations did not correlate to mining activity. The archived gizzard contents did provide a useful tool for documenting trends in metal depositional patterns related to an anthropogenic activity. Further, blue grouse ingesting grit particles during the time of active mining activity would have been exposed to toxicologically significant levels of cadmium. Gizzard lead concentrations were also of toxicological significance but not related to mining activity. This type of 'pulse' toxic metal exposure as a consequence of open-pit mining activity would not necessarily have been revealed through a 'snap-shot' of soil, plant or avian tissue trace metal analysis post-mining activity. - Research Highlights: {yields} Archived gizzard samples reveals mining history. {yields} Grit ingestion exposes grouse to cadmium and lead. {yields} Grit selection includes particles enriched in cadmium. {yields} Cadmium enriched particles are of toxicological significance.

The influence of chlorine on the fate and activity of alkali metals during the gasification of wood

Energy Technology Data Exchange (ETDEWEB)

Struis, R; Scala, C von; Schuler, A; Stucki, S [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Chlorine clearly inhibits the CO{sub 2}-gasification reaction of charcoal at 800{sup o}C. From this and other observations the picture emerges that the reduction in the gasification reactivity of the charcoal is intimately related to the deactivation of the catalytically active alkali metals residing in the wood due to the formation of the chloride salt. It is argued that the heavy metal chlorides will likely transfer the chlorine to the indigenous alkali metals during the pyrolysis stage of the wood. The fate of the thus formed alkali metal chlorides can then be either their removal from the sample (evaporation), or, when present at the gasification stage, re-activation (i.e., de-chlorination) under our gasification conditions. (author) 3 figs., 4 refs.

Metal-Organic Frameworks as Active Materials in Electronic Sensor Devices.

Science.gov (United States)

Campbell, Michael G; Dincă, Mircea

2017-05-12

In the past decade, advances in electrically conductive metal-organic frameworks (MOFs) and MOF-based electronic devices have created new opportunities for the development of next-generation sensors. Here we review this rapidly-growing field, with a focus on the different types of device configurations that have allowed for the use of MOFs as active components of electronic sensor devices.

In vitro effects of metals and pesticides on dehydrogenase activity in ...

African Journals Online (AJOL)

AJB SERVER

2007-01-04

Jan 4, 2007 ... Lin CH, Lerch RN, Kremer RJ, Garrett HC, Udawatta RP, George MF. (2005). Soil microbiological activities in vegetative buffer strips and their association with herbicide degradation. AFTA 2005 Conference. Proceedings pp 1 – 10. Mårtensson AM (1992). Effects of agrochemicals and heavy metals on.

Peroxotitanates for Biodelivery of Metals

Energy Technology Data Exchange (ETDEWEB)

Hobbs, David; Elvington, M.

2009-02-11

Metal-based drugs are largely undeveloped in pharmacology. One limiting factor is the systemic toxicity of metal-based compounds. A solid-phase, sequestratable delivery agent for local delivery of metals could reduce systemic toxicity, facilitating new drug development in this nascent area. Amorphous peroxotitanates (APT) are ion exchange materials with high affinity for several heavy metal ions, and have been proposed to deliver or sequester metal ions in biological contexts. In the current study, we tested a hypothesis that APT are able to deliver metals or metal compounds to cells. We exposed fibroblasts (L929) or monocytes (THP1) to metal-APT materials for 72 h in vitro, then measured cellular mitochondrial activity (SDH-MTT method) to assess the biological impact of the metal-APT materials vs. metals or APT alone. APT alone did not significantly affect cellular mitochondrial activity, but all metal-APT materials suppressed the mitochondrial activity of fibroblasts (by 30-65% of controls). The concentration of metal-APT materials required to suppress cellular mitochondrial activity was below that required for metals alone, suggesting that simple extracellular release of the metals from the metal-APT materials was not the primary mechanism of mitochondrial suppression. In contrast to fibroblasts, no metal-APT material had a measurable effect on THP1 monocyte mitochondrial activity, despite potent suppression by metals alone. This latter result suggested that 'biodelivery' by metal-APT materials may be cell type-specific. Therefore, it appears that APT are plausible solid phase delivery agents of metals or metal compounds to some types of cells for potential therapeutic effect.

Impact of repeated single-metal and multi-metal pollution events on soil quality.

Science.gov (United States)

Burges, Aritz; Epelde, Lur; Garbisu, Carlos

2015-02-01

Most frequently, soil metal pollution results from the occurrence of repeated single-metal and, above all, multi-metal pollution events, with concomitant adverse consequences for soil quality. Therefore, in this study, we evaluated the impact of repeated single-metal and multi-metal (Cd, Pb, Cu, Zn) pollution events on soil quality, as reflected by the values of a variety of soil microbial parameters with potential as bioindicators of soil functioning. Specifically, parameters of microbial activity (potentially mineralizable nitrogen, β-glucosidase and acid phosphatase activity) and biomass (fungal and bacterial gene abundance by RT-qPCR) were determined, in the artificially metal-polluted soil samples, at regular intervals over a period of 26 weeks. Similarly, we studied the evolution over time of CaCl2-extractable metal fractions, in order to estimate metal bioavailability in soil. Different metals showed different values of bioavailability and relative bioavailability ([metal]bio/[metal]tot) in soil throughout the experiment, under both repeated single-metal and multi-metal pollution events. Both repeated Zn-pollution and multi-metal pollution events led to a significant reduction in the values of acid phosphatase activity, and bacterial and fungal gene abundance, reflecting the negative impact of these repeated events on soil microbial activity and biomass, and, hence, soil quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of co-existing plant specie on soil microbial activity under heavy metal stress

International Nuclear Information System (INIS)

Nwuche, C. O.; Ugoji, E. O.

2010-01-01

The influence of plant primary compounds on the activity of soil microbial communities under heavy metal stress was studied in a pot-culture field experiment conducted in a green house. Amaranthus spinosus was cultivated in an agricultural soil previously amended in the laboratory with solutions of different trace elements in two separate treatment modes: singly and in combination. Culture-independent metabolism based indices such as the rate of carbon and nitrogen mineralization, microbial biomass carbon and soil basal respiration were monitored fortnightly over a period of six weeks. Result shows that plant detritus have significant modifying effect on soil microbe-metal interactions. Data on microbial and biochemical processes in the respective mesocosms did not vary from control; not even in mesocosms containing very high concentrations of copper, zinc and nickel. The soil microbial biomass carbon and the rate of carbon and nitrogen cycling were not impeded by the respective metal treatment while the respiration responses increased as a result of increase in metabolic activity of the soil microbes. The plant based substrates enabled the soil microflora to resist high metal contamination because of its tendency to absorb large amounts of inorganic cations.

Late metal carbene complexes generated by multiple C-H activations: examining the continuum of M=C bond reactivity.

Science.gov (United States)

Whited, Matthew T; Grubbs, Robert H

2009-10-20

Unactivated C(sp(3))-H bonds are ubiquitous in organic chemicals and hydrocarbon feedstocks. However, these resources remain largely untapped, and the development of efficient homogeneous methods for hydrocarbon functionalization by C-H activation is an attractive and unresolved challenge for synthetic chemists. Transition-metal catalysis offers an attractive possible means for achieving selective, catalytic C-H functionalization given the thermodynamically favorable nature of many desirable partial oxidation schemes and the propensity of transition-metal complexes to cleave C-H bonds. Selective C-H activation, typically by a single cleavage event to produce M-C(sp(3)) products, is possible through myriad reported transition-metal species. In contrast, several recent reports have shown that late transition metals may react with certain substrates to perform multiple C-H activations, generating M=C(sp(2)) complexes for further elaboration. In light of the rich reactivity of metal-bound carbenes, such a route could open a new manifold of reactivity for catalytic C-H functionalization, and we have targeted this strategy in our studies. In this Account, we highlight several early examples of late transition-metal complexes that have been shown to generate metal-bound carbenes by multiple C-H activations and briefly examine factors leading to the selective generation of metal carbenes through this route. Using these reports as a backdrop, we focus on the double C-H activation of ethers and amines at iridium complexes supported by Ozerov's amidophosphine PNP ligand (PNP = [N(2-P(i)Pr(2)-4-Me-C(6)H(3))(2)](-)), allowing isolation of unusual square-planar iridium(I) carbenes. These species exhibit reactivity that is distinct from the archetypal Fischer and Schrock designations. We present experimental and theoretical studies showing that, like the classical square-planar iridium(I) organometallics, these complexes are best described as nucleophilic at iridium. We discuss

Impact of heavy metal on activity of some microbial enzymes in the riverbed sediments: Ecotoxicological implications in the Ganga River (India).

Science.gov (United States)

Jaiswal, Deepa; Pandey, Jitendra

2018-04-15

We studied the extracellular enzyme activity (EEA) in the riverbed sediment along a 518km gradient of the Ganga River receiving carbon and nutrient load from varied human sources. Also, we tested, together with substrate-driven stimulation, if the heavy metal accumulated in the sediment inhibits enzyme activities. Because pristine values are not available, we considered Dev Prayag, a least polluted site located 624km upstream to main study stretch, as a reference site. There were distinct increases in enzyme activities in the sediment along the study gradient from Dev Prayag, however, between-site differences were in concordance with sediment carbon(C), nitrogen (N) and phosphorus (P). Fluorescein diacetate hydrolysis (FDAase), β-glucosidase (Glu) and protease activities showed positive correlation with C, N and P while alkaline phosphatase was found negatively correlated with P. Enzyme activities were found negatively correlated with heavy metal, although ecological risk index (E R i ) varied with site and metal species. Dynamic fit curves showed significant positive correlation between heavy metal and microbial metabolic quotient (qCO 2 ) indicating a decrease in microbial activity in response to increasing heavy metal concentrations. This study forms the first report linking microbial enzyme activities to regional scale sediment heavy metal accumulation in the Ganga River, suggests that the microbial enzyme activities in the riverbed sediment were well associated with the proportion of C, N and P and appeared to be a sensitive indicator of C, N and P accumulation in the river. Heavy metal accumulated in the sediment inhibits enzyme activities, although C rich sediment showed relatively low toxicity due probably to reduced bioavailability of the metal. The study has relevance from ecotoxicological as well as from biomonitoring perspectives. Copyright © 2017 Elsevier Inc. All rights reserved.

Highly reproducible alkali metal doping system for organic crystals through enhanced diffusion of alkali metal by secondary thermal activation.

Science.gov (United States)

Lee, Jinho; Park, Chibeom; Song, Intek; Koo, Jin Young; Yoon, Taekyung; Kim, Jun Sung; Choi, Hee Cheul

2018-05-16

In this paper, we report an efficient alkali metal doping system for organic single crystals. Our system employs an enhanced diffusion method for the introduction of alkali metal into organic single crystals by controlling the sample temperature to induce secondary thermal activation. Using this system, we achieved intercalation of potassium into picene single crystals with closed packed crystal structures. Using optical microscopy and Raman spectroscopy, we confirmed that the resulting samples were uniformly doped and became K 2 picene single crystal, while only parts of the crystal are doped and transformed into K 2 picene without secondary thermal activation. Moreover, using a customized electrical measurement system, the insulator-to-semiconductor transition of picene single crystals upon doping was confirmed by in situ electrical conductivity and ex situ temperature-dependent resistivity measurements. X-ray diffraction studies showed that potassium atoms were intercalated between molecular layers of picene, and doped samples did not show any KH- nor KOH-related peaks, indicating that picene molecules are retained without structural decomposition. During recent decades, tremendous efforts have been exerted to develop high-performance organic semiconductors and superconductors, whereas as little attention has been devoted to doped organic crystals. Our method will enable efficient alkali metal doping of organic crystals and will be a resource for future systematic studies on the electrical property changes of these organic crystals upon doping.

Exposure to airborne metals and particulate matter and risk for youth adjudicated for criminal activity

Energy Technology Data Exchange (ETDEWEB)

Haynes, Erin N., E-mail: Erin.Haynes@uc.edu [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267 (United States); Chen, Aimin, E-mail: Aimin.Chen@uc.edu [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267 (United States); Ryan, Patrick, E-mail: Patrick.Ryan@uc.edu [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267 (United States); Succop, Paul, E-mail: Paul.Succop@uc.edu [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267 (United States); Wright, John, E-mail: John.Wright@uc.edu [College of Education, Criminal Justice, and Human Services, University of Cincinnati, Cincinnati, OH 45221 (United States); Dietrich, Kim N., E-mail: Kim.Dietrich@uc.edu [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267 (United States)

2011-11-15

Antisocial behavior is a product of multiple interacting sociohereditary variables, yet there is increasing evidence that metal exposure, particularly, manganese and lead, play a role in its epigenesis. Other metals, such as arsenic, cadmium, chromium, and mercury, and exposure to traffic-related air pollution, such as fine particulate matter ({<=}2.5 {mu}m) have been associated with neurological deficits, yet largely unexplored with respect to their relationship with delinquent behavior. The purpose of this study is to evaluate the ecological relationship between county-wide reported airborne emissions of air metals, particulate matter, and youth adjudicated for criminal activity. Metal exposure data were collected from the Environmental Protection Agency AirData. Population statistics were obtained from the United States Census 2000 and adjudication data was obtained from the Courts of Common Pleases from each Ohio County. Simple correlations were calculated with the percentage of adjudications, all covariates, and estimated metal air emissions. Separate negative binomial regression models for each pollutant were used to provide an estimated risk ratio of pollutant emissions on the risk of adjudication for all Ohio counties adjusting for urban-rural residence, percentage of African Americans, median family income, percentage of family below poverty, percentage of high school graduation in 25 years and older populations, and population density. Metal emissions and PM in 1999 were all correlated with adjudication rate (2003-2005 average). Metal emissions were associated with slightly higher risk of adjudication, with about 3-4% increased risk per natural log unit of metal emission except chromium. The associations achieved statistical significance for manganese and mercury. The particulate matter {<=}2.5 and {<=}10 {mu}m emissions had a higher risk estimate, with 12% and 19% increase per natural log unit emission, respectively, and also achieved statistical

Exposure to airborne metals and particulate matter and risk for youth adjudicated for criminal activity

International Nuclear Information System (INIS)

Haynes, Erin N.; Chen, Aimin; Ryan, Patrick; Succop, Paul; Wright, John; Dietrich, Kim N.

2011-01-01

Antisocial behavior is a product of multiple interacting sociohereditary variables, yet there is increasing evidence that metal exposure, particularly, manganese and lead, play a role in its epigenesis. Other metals, such as arsenic, cadmium, chromium, and mercury, and exposure to traffic-related air pollution, such as fine particulate matter (≤2.5 μm) have been associated with neurological deficits, yet largely unexplored with respect to their relationship with delinquent behavior. The purpose of this study is to evaluate the ecological relationship between county-wide reported airborne emissions of air metals, particulate matter, and youth adjudicated for criminal activity. Metal exposure data were collected from the Environmental Protection Agency AirData. Population statistics were obtained from the United States Census 2000 and adjudication data was obtained from the Courts of Common Pleases from each Ohio County. Simple correlations were calculated with the percentage of adjudications, all covariates, and estimated metal air emissions. Separate negative binomial regression models for each pollutant were used to provide an estimated risk ratio of pollutant emissions on the risk of adjudication for all Ohio counties adjusting for urban–rural residence, percentage of African Americans, median family income, percentage of family below poverty, percentage of high school graduation in 25 years and older populations, and population density. Metal emissions and PM in 1999 were all correlated with adjudication rate (2003–2005 average). Metal emissions were associated with slightly higher risk of adjudication, with about 3–4% increased risk per natural log unit of metal emission except chromium. The associations achieved statistical significance for manganese and mercury. The particulate matter ≤2.5 and ≤10 μm emissions had a higher risk estimate, with 12% and 19% increase per natural log unit emission, respectively, and also achieved statistical

GO@CuSilicate nano-needle arrays hierarchical structure: a new route to prepare high optical transparent, excellent self-cleaning and anticorrosion superhydrophobic surface

Energy Technology Data Exchange (ETDEWEB)

Fan, Ping; Chen, Jingyi; Yang, Jintao; Chen, Feng; Zhong, Mingqiang, E-mail: zhongmingqiang@hotmail.com [Zhejiang University of Technology, College of Materials Science and Engineering (China)

2017-02-15

Transparent superhydrophobic coatings, which are highly desired for the protection of material surfaces, have been limited to particular kinds of materials, e.g. silicon dioxide. In this work, a hybrid compound of graphene oxide and copper silicate with hierarchical structure was developed and was used to fabricate coatings. Due to the high transparency of graphene oxide and the nanoscopic roughness created by nanoneedles of CuSilicate, with very low compound loading (0.052 mg/cm{sup 2}), the as-prepared coating was found not only showing superhydrophobic properties with a water contact angle (CA) of ∼152° and a near zero sliding angle (SA) of 0.5 but also showing high optical transparent (light transmittance is as high as 94.5 % at 500 nm). Furthermore, this surface also showed efficient anticorrosion properties and excellent self-cleaning ability. This study not only fabricated a new surface with transparency and surperhydrophobicity based on graphene materials, but also hopefully offers a method for the fabrication of multifunctional coatings.

Overview of EU activities on DEMO liquid metal breeder blanket

International Nuclear Information System (INIS)

Giancarli, L.; Proust, E.; Malang, S.; Reimann, J.; Perujo, A.

1994-01-01

The present paper gives an overview of both design and experimental activities within the European Union (EU) concerning the development of liquid metal breeder blankets for DEMO. After several years of studies on breeding blankets, two blanket concepts are presently considered, both using the eutectic Pb-17Li: the dual-coolant concept and the water-cooled concept. The analysis of such concepts has permitted to identify the experimental areas where further data are required. Tritium control and MHD-issues are, at present, the activities on which is devoted the greatest effort within the EU. (authors). 4 figs., 4 tabs., 39 refs

Effect of the chelation of metal cation on the antioxidant activity of chondroitin sulfates.

Science.gov (United States)

Ajisaka, Katsumi; Oyanagi, Yutaka; Miyazaki, Tatsuo; Suzuki, Yasuhiro

2016-06-01

The antioxidant potencies of chondroitin sulfates (CSs) from shark cartilage, salmon cartilage, bovine trachea, and porcine intestinal mucosa were compared by three representative methods for the measurement of the antioxidant activity; DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity. CSs from salmon cartilage and bovine trachea showed higher potency in comparison with CSs from shark cartilage and porcine intestinal mucosa. Next, CS from salmon cartilage chelating with Ca(2+), Mg(2+), Mn(2+), or Zn(2+) were prepared, and their antioxidant potencies were compared. CS chelating with Ca(2+) or Mg(2+) ions showed rather decreased DPPH radical scavenging activity in comparison with CS of H(+) form. In contrast, CS chelating with Ca(2+) or Mg(2+) ion showed remarkably enhanced superoxide radical scavenging activity than CS of H(+) or Na(+) form. Moreover, CS chelating with divalent metal ions, Ca(2+), Mg(2+), Mn(2+), or Zn(2+), showed noticeably higher hydroxyl radical scavenging activity than CS of H(+) or Na(+) form. The present results revealed that the scavenging activities of, at least, superoxide radical and hydroxyl radical were enhanced by the chelation with divalent metal ions.

Heavy metals uptake by sonicated activated sludge: Relation with floc surface properties

International Nuclear Information System (INIS)

Laurent, Julien; Casellas, Magali; Dagot, Christophe

2009-01-01

The effects of sonication of activated sludge on heavy metal uptake were in a first time investigated in respect with potential modifications of floc surface properties. The treatment led to the simultaneous increase of specific surface area and of the availability of negative and/or hydrophilic sites. In parallel, organic matter was released in the soluble fraction. Sorption isotherms of cadmium and copper showed that uptake characteristics and mechanisms were highly dependent on both heavy metal species and specific energy supplied. The increase of both specific surface area and fixation sites availability led to the increase of Cd(II) uptake. For Cu(II), organic matter released in soluble phase during the treatment seemed to act as a ligand and to limit adsorption on flocs surface. Three different heavy metals uptake mechanisms have been identified: proton exchange, ion exchange and (co)precipitation

Newly developed active braze powders based on commercial nickel brazes using zirconium as active element for joining ceramic to metal; Entwicklung von neuen Aktivlotpulvern auf Basis kommerzieller Nickellote mit Zirkon als aktivelement zum Fuegen von Keramik-Metall-Verbunden

Energy Technology Data Exchange (ETDEWEB)

Bobzin, K.; Schlaefer, T.; Kopp, N.; Schlegel, A. [Institut fuer Oberflaechentechnik der RWTH Aachen (Germany)

2010-06-15

The increased requirements of highly stressed components, concerning the resistance to thermal-induced stresses, oxidation, corrosion, hardness as well as wear resistance make high-performance technical ceramics ideally suited for such applications. On the other hand they exhibit properties like high brittleness, partly low thermal shock resistance, low workability and consequential limitations in the engineering design. Hybrid material concepts, as combination of high-performance technical ceramics and metallic engineering materials, can offer interesting technological solutions, if suitable and joining technologies are available. Active brazing, which is a very flexible joining technology in respect of the material selection, arises for the development of new and innovative applications, such as high-temperature fuel cells. Currently silver/copper, copper and silver active brazing filler metals are already used in the industry and are characterised by a decrease of their mechanical strength at approx. 500 C. Referring to this, gold and palladium active brazing filler metals show better features, but because of their high price, they are seldom used. The aim of the reported investigations is the development of active brazing filler metals with reasonable raw materials costs for working temperatures above 500 C and moreover to be used in hydrocarbonated environments with better corrosion-resistance than silver/copper, copper and silver active brazing filler metals. Experimental brazing filler metals with zirconium as surface-active element has been manufactured on the basis of nickel brazing filler metals NI 102, NI 105 and NI 107. The modification of each nickel brazing filler metal was carried out on the one hand by powder metallurgy, whereby zirconium hydride has been mixed or mechanically alloyed. On the other hand the nickel brazing filler metals have been alloyed with zirconium by melting metallurgy. The content of active metal varied between 2 weight-% and

Toxic responses of cytochrome P450 sub-enzyme activities to heavy metals exposure in soil and correlation with their bioaccumulation in Eisenia fetida.

Science.gov (United States)

Cao, Xiufeng; Bi, Ran; Song, Yufang

2017-10-01

The dose- and time- dependent responses of cytochrome P450 (CYP) sub-enzyme activities to heavy metals in soil, and the relationships between biomarker responses and metal bioaccumulation in Eisenia fetida were evaluated. Earthworms were exposed to soils spiked with increasing doses of Cd, Cu, Pb or Zn for 21 d. Results demonstrated that EROD and CYP3A4 activities responded significantly with increasing dose and exposure duration. EROD activity significantly (P metal burdens had significant correlation with the total metal concentrations in soil (P metal concentration in soil. The order of metal bioavailability to E. fetida was Cd > Zn > Cu > Pb. CYP3A4 activity in Pb-exposed earthworms had a significant correlation with the accumulated metal (P heavy metals exposure, and we also concluded that different biomarkers with multiple durations could be conducted in the eco-toxicological diagnosis of soil pollution. Copyright © 2017 Elsevier Inc. All rights reserved.

Removal of metals from landfill leachate by sorption to activated carbon, bone meal and iron fines.

Science.gov (United States)

Modin, Hanna; Persson, Kenneth M; Andersson, Anna; van Praagh, Martijn

2011-05-30

Sorption filters based on granular activated carbon, bone meal and iron fines were tested for their efficiency of removing metals from landfill leachate. Removal of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sr and Zn were studied in a laboratory scale setup. Activated carbon removed more than 90% of Co, Cr, Cu, Fe, Mn and Ni. Ca, Pb, Sr and Zn were removed but less efficiently. Bone meal removed over 80% of Cr, Fe, Hg, Mn and Sr and 20-80% of Al, Ca, Cu, Mo, Ni, Pb and Zn. Iron fines removed most metals (As, Ca, Co, Cr, Cu, Fe, Mg, Mn, Pb, Sr and Zn) to some extent but less efficiently. All materials released unwanted substances (metals, TOC or nutrients), highlighting the need to study the uptake and release of a large number of compounds, not only the target metals. To remove a wide range of metals using these materials two or more filter materials may need to be combined. Sorption mechanisms for all materials include ion exchange, sorption and precipitation. For iron fines oxidation of Fe(0) seems to be important for metal immobilisation. Copyright © 2011 Elsevier B.V. All rights reserved.

Abundance, composition and activity of ammonia oxidizer and denitrifier communities in metal polluted rice paddies from South China.

Directory of Open Access Journals (Sweden)

Yuan Liu

Full Text Available While microbial nitrogen transformations in soils had been known to be affected by heavy metal pollution, changes in abundance and community structure of the mediating microbial populations had been not yet well characterized in polluted rice soils. Here, by using the prevailing molecular fingerprinting and enzyme activity assays and comparisons to adjacent non-polluted soils, we examined changes in the abundance and activity of ammonia oxidizing and denitrifying communities of rice paddies in two sites with different metal accumulation situation under long-term pollution from metal mining and smelter activities. Potential nitrifying activity was significantly reduced in polluted paddies in both sites while potential denitrifying activity reduced only in the soils with high Cu accumulation up to 1300 mg kg-1. Copy numbers of amoA (AOA and AOB genes were lower in both polluted paddies, following the trend with the enzyme assays, whereas that of nirK was not significantly affected. Analysis of the DGGE profiles revealed a shift in the community structure of AOA, and to a lesser extent, differences in the community structure of AOB and denitrifier between soils from the two sites with different pollution intensity and metal composition. All of the retrieved AOB sequences belonged to the genus Nitrosospira, among which species Cluster 4 appeared more sensitive to metal pollution. In contrast, nirK genes were widely distributed among different bacterial genera that were represented differentially between the polluted and unpolluted paddies. This could suggest either a possible non-specific target of the primers conventionally used in soil study or complex interactions between soil properties and metal contents on the observed community and activity changes, and thus on the N transformation in the polluted rice soils.

The history and future of thermal sprayed galvanically active metallic anticorrosion coatings used on pipelines and steel structures in the oil and gas industry

Energy Technology Data Exchange (ETDEWEB)

Rodijnen, Fred van [Sulzer Metco, Duisburg (Germany)

2008-07-01

Since its invention by M. U. Schoop in the beginning of the 20th century, thermal spray has been used for corrosion protection applications in naval, on-shore, submerged and atmospheric environments. Thermally sprayed coatings of zinc, zinc alloys, aluminum and aluminum alloys are currently the most popular materials used for active corrosion protection of steel and concrete, which can be applied using either of the widely known thermal spray processes of combustion wire or electric arc wire. In the oil and gas exploration and production industry, corrosion protection applications using these technologies have evolved since the early sixties. Thermal spray technology has successfully been used to protect steel-based materials from corrosion in many different fields of application like platforms and pipelines. The most used material in the oil and gas industry is TSA (Thermally Sprayed Aluminum) coating. TSA coatings, with a lifetime of 25 to 30 years, require no maintenance except for cosmetic reasons when painted. The surface temperature of a TSA can go as high as 480 deg C. Although TS (Thermal Spray) is an older process, the number of applications and the number of m{sup 2} it is applied to is still increasing resulting from its maintenance-free and reliable active corrosion-protection features. (author)

Friction and metal transfer for single-crystal silicon carbide in contact with various metals in vacuum

International Nuclear Information System (INIS)

Miyoshi, K.; Buckley, D.H.

1978-04-01

Sliding friction experiments were conducted with single-crystal silicon carbide in contact with transition metals (tungsten, iron, rhodium, nickel, titanium, and cobalt), copper, and aluminum. Results indicate the coefficient of friction for a silicon carbide-metal system is related to the d bond character and relative chemical activity of the metal. The more active the metal, the higher the coefficient of friction. All the metals examined transferred to the surface of silicon carbide in sliding. The chemical activity of metal to silicon and carbon and shear modulus of the metal may play important roles in metal transfer and the form of the wear debris. The less active metal is, and the greater resistance to shear it has, with the exception of rhodium and tungsten, the less transfer to silicon carbide

Synthesis and characterization of transition metal complexes derived from some biologically active furoic acid hydrazones

Directory of Open Access Journals (Sweden)

P. Venkateswar Rao

2007-04-01

Full Text Available Two new physiologically active ligands, N’-2-[(E-1-hydroxy-4-methyl-2-oxo-2H-8-chromenyl ethylidene-2-furan carbohydrazide (HMCFCH and N’-2-[(Z-1-(4-hydroxy-6-methyl-2-oxo-2H-pyranyl ethylidene]-furan carbohydrazide (HMPFCH and their VO(II, Mn(II, Fe(II, Co(II, Ni(II and Cu(II complexes have been prepared. The ligands and the metal complexes have been characterized by elemental analyses, electrical conductance, magnetic susceptibility measurements, UV-Vis, IR, and ESR spectroscopic data. Basing on the above data, Fe(II and Co(II complexes of HMCFCH and HMPFCH have been assigned a dimeric octahedral geometry. VO(II complexes of HMCFCH and HMPFCH have been assigned sulfate bridged dimeric square pyramidal geometry. Mn(II complex of HMCFCH has been assigned a dimeric octahedral geometry, where as Mn(II complex of HMPFCH has been ascribed to monomeric octahedral geometry. Cu(II and Ni(II complexes of HMCFCH have been ascribed to a polymeric structure. Ni(II complex of HMPFCH has been assigned a dimeric square planar geometry. Cu(II complex of HMPFCH has been proposed an octahedral geometry. The ligands and their metal chelates were screened against S. aureus and P. aeruginosa. The ligands and the metal complexes have been found to be active against these microorganisms. The ligands show more activity than the metal complexes.

Anticorrosion protection of strength bolts

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Jiří Votava

2012-01-01

Full Text Available Corrosion damage may, from the technical point of view, cause changes in mechanical and physical characteristics in particular, at the same time it may also cause changes in surface geometry. These aspects are likely to manifest themselves in all steel parts. The presented study looks at corrosion protection in bolts and bolt connections protected by metal coating based on zinc.Four different types of passivation, easily accessible on the Czech market, have been selected for this experiment. They are as follows: first, galvanic plating using white zinc; second, galvanic plating using yellow zinc; third, hot dip galvanizing; fourth, specific type of plating using the technology Dacromet 500 LC. In order to compare the given parameters there have been selected a unified M bolt size of 8 × 30 mm. The experimental part of this study can be further divided into two phases. The initial phase puts stress on the exact specification of the protection layer, namely, the analysis and establishment of the elemental compositon contained in the given coating, its microhardness, weight and thickness. The second phase of the experiment analyses the results of tests according to the norm ČSN ISO 9227 (Salt Fog Test and ČSN ISO 6988 (Sulphur Dioxide Test. With the tests we have concentrated on the initial stages of corrosion degradation and its overall process.

Crystal structures reveal metal-binding plasticity at the metallo-β-lactamase active site of PqqB from Pseudomonas putida

Energy Technology Data Exchange (ETDEWEB)

Tu, Xiongying; Latham, John A.; Klema, Valerie J.; Evans III, Robert L.; Li, Chao; Klinman, Judith P.; Wilmot, Carrie M. (UMM); (UCB)

2017-08-19

PqqB is an enzyme involved in the biosynthesis of pyrroloquinoline quinone and a distal member of the metallo-β-lactamase (MBL) superfamily. PqqB lacks two residues in the conserved signature motif HxHxDH that makes up the key metal-chelating elements that can bind up to two metal ions at the active site of MBLs and other members of its superfamily. Here, we report crystal structures of PqqB bound to Mn2+, Mg2+, Cu2+, and Zn2+. These structures demonstrate that PqqB can still bind metal ions at the canonical MBL active site. The fact that PqqB can adapt its side chains to chelate a wide spectrum of metal ions with different coordination features on a uniform main chain scaffold demonstrates its metal-binding plasticity. This plasticity may provide insights into the structural basis of promiscuous activities found in ensembles of metal complexes within this superfamily. Furthermore, PqqB belongs to a small subclass of MBLs that contain an additional CxCxxC motif that binds a structural Zn2+. Our data support a key role for this motif in dimerization.

Physicochemical properties of metal-doped activated carbons and relationship with their performance in the removal of SO2 and NO

International Nuclear Information System (INIS)

Gao Xiang; Liu Shaojun; Zhang Yang; Luo Zhongyang; Cen Kefa

2011-01-01

Research highlights: → Cu and Fe were partly reduced by carbon during preparation. → Metal-involved SO 2 removal pathways were catalytic oxidation, reaction and adsorption. → Good performances of SO 2 and NO removal depended on the metal redox pairs. - Abstract: Several metal-doped activated carbons (Fe, Co, Ni, V, Mn, Cu and Ce) were prepared and characterized. The results of N 2 adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy indicated that some metals (Cu and Fe) were partly reduced by carbon during preparation. Activity tests for the removal of SO 2 and the selective catalytic reduction of NO with ammonia were carried out. Due to different physicochemical properties, different pathways for the SO 2 removal had been put out, i.e., catalytic oxidation, direct reaction and adsorption. This classification depended on the standard reduction potentials of metal redox pairs. Samples impregnated with V, Ce and Cu showed good activity for NO reduction by NH 3 , which was also ascribed to the reduction potential values of metal redox pairs. Ce seemed to be a promising alternative to V due to the higher activity in NO reduction and the nontoxic property. A metal cation which could easily convert between the two valences seemed to be crucial to the good performance of both SO 2 and NO removal, just like V and Cu.

Effects of long-term radionuclide and heavy metal contamination on the activity of microbial communities, inhabiting uranium mining impacted soils.

Science.gov (United States)

Boteva, Silvena; Radeva, Galina; Traykov, Ivan; Kenarova, Anelia

2016-03-01

Ore mining and processing have greatly altered ecosystems, often limiting their capacity to provide ecosystem services critical to our survival. The soil environments of two abandoned uranium mines were chosen to analyze the effects of long-term uranium and heavy metal contamination on soil microbial communities using dehydrogenase and phosphatase activities as indicators of metal stress. The levels of soil contamination were low, ranging from 'precaution' to 'moderate', calculated as Nemerow index. Multivariate analyses of enzyme activities revealed the following: (i) spatial pattern of microbial endpoints where the more contaminated soils had higher dehydrogenase and phosphatase activities, (ii) biological grouping of soils depended on both the level of soil contamination and management practice, (iii) significant correlations between both dehydrogenase and alkaline phosphatase activities and soil organic matter and metals (Cd, Co, Cr, and Zn, but not U), and (iv) multiple relationships between the alkaline than the acid phosphatase and the environmental factors. The results showed an evidence of microbial tolerance and adaptation to the soil contamination established during the long-term metal exposure and the key role of soil organic matter in maintaining high microbial enzyme activities and mitigating the metal toxicity. Additionally, the results suggested that the soil microbial communities are able to reduce the metal stress by intensive phosphatase synthesis, benefiting a passive environmental remediation and provision of vital ecosystem services.

Thin layer activation : on-line monitoring of metal loss in process plant

International Nuclear Information System (INIS)

Boulton, L.H.; Wallace, G.

1993-01-01

Corrosion, erosion and wear of metals is a common cause of failure in some process plant and equipment. Monitoring of these destructive effects has been done for many years to help plant engineers minimise the damage, in order to avoid unexpected failures and unscheduled shutdowns. Traditional methods of monitoring, such as standard NDT techniques, inform the engineer of what has happened, providing data such as culmulative loss of wall thickness. The modern approach to monitoring however, is to employ a technique which gives both current loss rates as well as integrated losses. Thin Layer Activation (TLA) provides on-line monitoring of corrosion, erosion and wear of metals, to a high degree of accuracy. It also gives cumulative information which can be backed up with weight-loss results if required. Thus current rather than historical loss rates are measured before any significant loss of metal has occurred. (author). 14 refs., 2 figs

Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls.

Science.gov (United States)

Rao, M Madhava; Ramana, D K; Seshaiah, K; Wang, M C; Chien, S W Chang

2009-07-30

Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g(-1) for Pb(II), 21.2 mg g(-1) for Zn(II), 19.5 mg g(-1) for Cu(II), and 15.7 mg g(-1) for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls

International Nuclear Information System (INIS)

Rao, M. Madhava; Ramana, D.K.; Seshaiah, K.; Wang, M.C.; Chien, S.W. Chang

2009-01-01

Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g -1 for Pb(II), 21.2 mg g -1 for Zn(II), 19.5 mg g -1 for Cu(II), and 15.7 mg g -1 for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

Gill ATPase activity in Procambarus clarkii as an indicator of heavy metal pollution

Energy Technology Data Exchange (ETDEWEB)

Torreblanca, A.; Del Ramo, J.; Diaz-Mayans, J. (Univ. of Valencia (Spain))

1989-06-01

Lake Albufera and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic industrial residues, including heavy metals, from the many urban and waste waters of this area. The American red crayfish, Procambarus clarkii have a high resistance to toxic effects of heavy metals. The sublethal effects of heavy metals on gills of fish and aquatic invertebrates have been extensively studied. Some metabolic disturbances and histologic damages have been reported, as well as osmoregulation alterations. However, little work has been done about the effect of heavy metals on Na,K and Mg-ATPases of freshwater invertebrate gills. Na,K-ATPase is the prime mediator of ion transport across cellular membranes and plays a central role in whole body ion regulation in marine and estuarine animals. Na,K-ATPase has been reviewed and assessed as a potentially useful indicator of pollution stress in aquatic animals. The purpose of this study is look for the relation, if any, between crayfish gill ATP-ase activity changes and metal exposure in laboratory. This find would allow the authors to assay this potential indicator in the field.

Synthesis, Characterization and Antibacterial Activity of Novel 1,3-Diethyl-1,3-bis(4-nitrophenylurea and Its Metal(II Complexes

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Hoda Pasdar

2017-12-01

Full Text Available A bioactive ligand and its dinuclear metal(II complexes were synthesized and characterized by Fourier-transform infrared spectroscopy (FT-IR, ultraviolet-visible (UV-Visible, nuclear magnetic resonance (1H-NMR, mass spectroscopy and molar conductance measurements. The ligand has been crystalized in the monoclinic system with a P21/c space group. The biological activities of metal complexes were evaluated using disc diffusion and broth dilution methods. In vitro antibacterial activities of the ligand and their metal complexes were examined against two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus and two Gram-negative bacteria (Escherichia coli and Serratia marcescens and compared to the standard drugs. It was found that metal complexes displayed much higher antibacterial activities and better inhibitory effects than that of the ligand and standard drugs. Among these complexes, the compound having Zn-metal showed greater antibacterial activity against all four tested bacteria and was more effective against Serratia marcescens with the zone inhibition diameter of 26 mm and MIC value of 31.25 µg/mL.

IMPROVEMENT OF CORROSION PROTECTION OF PETROLEUM FACILITIES BY THE DEVELOPMENT OF A NEW HIGH-POTENTIAL COATING

Energy Technology Data Exchange (ETDEWEB)

Allaoua-Nazef, M.; Daouadji, M.

2007-07-01

Corrosion affects many oil and gas facilities. It is the principal cause of leaks of products and rupture of storage tanks and pipelines, resulting sometimes in catastrophic damages (human damages, pollution of the natural environment, additional costs for repair, prolonged stop of pumping). Growing environmental concerns regarding the use of heavy metals in anti-corrosion coating formulations led to a new coating strategy using intrinsically conducting polymers (ICPs) as key components. (ICPs) as a new materials class provides a unique set of new properties and coatings based on these polymers are able to meet high demands and are outperforming even the best conventional anti-corrosion coating systems. This new generation of high-potential coatings can provide a significant cost reduction for the oil and gas industry, due to the specific properties of the ICPs which can work indefinitely as a redox catalysts and provide continuous protection as long as the mechanical integrity of the polymer films remains intact. Our paper focuses on the development of a nonconventional coating based on a specific conducting polymer which is never used before in any coating formulations. The developed coating is able to provide high anticorrosion performances with safety, environmental benefits and costs reduction. (auth)

Biological activities of some Fluoroquinolones-metal complexes

African Journals Online (AJOL)

McRoy

DNA cleavage studies of some synthesized metal complexes of fluoroquinolone ... Although the FQs are generally characterized by a broad antimicrobial spectrum ..... six Coordinate 3rd metal complexes with N- (5 –Phenyl-3,4- thiadiazol-2-yl).

Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

Directory of Open Access Journals (Sweden)

Fazli Wahid

2017-11-01

Full Text Available Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag, gold (Au, zinc oxide (ZnO, copper oxide (CuO, titanium dioxide (TiO2 and magnesium oxide (MgO have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.

Synthesis, physico-chemical characterization and biological activity of 2-aminobenzimidazole complexes with different metal ions

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Podunavac-Kuzmanović Sanja O.

2004-01-01

Full Text Available Complexes of 2-aminobenzimidazole (L with nitrates of cobalt(II nickel(II, copper (II, zinc(II and silver(I were synthesized. The molar ratio metal:ligand in the reaction of the complex formation was 1:2. It should be noticed, that the reaction of all the metal salts yielded bis(ligand complexes of the general formula M(L2(NO32 × nH2O (M=Co, Ni Cu, Zn or Ag; n=0, 1, 2 or 6. The complexes were characterized by elemental analysis of the metal, molar conductivity, magnetic susceptibility measurements and IR spectra. Co(II, Ni(II and Cu(II complexes behave as non-electrolytes, whilst Zn(II and Ag(I are 1:1 electrolytes. Cu(II complex has a square-planar stereochemistry, Ag(I complex is linear, whilst the Co(II, Ni(II and Zn(II complexes have a tetrahedral configuration. In all the complexes ligand is coordinated by participation of the pyridine nitrogen of the benzimidazole ring. The antimicrobial activity of the ligand and its complexes against Pseudomonas aeruginosa, Bacillus sp. Staphylococcus aureus and Saccharomyces cerevisiae was investigated. The effect of metal on the ligand antimicrobial activity is discussed.

Efficacy of Chicken Litter and Wood Biochars and Their Activated Counterparts in Heavy Metal Clean up from Wastewater

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Isabel M. Lima

2015-09-01

Full Text Available It is known that properties of activated biochars are tightly associated with those of the original feedstock as well as pyrolysis and activation conditions. This study examined two feedstock types, pine wood shavings and chicken litter, to produce biochars at two different pyrolysis temperatures and subsequently activated by steam, acid or base. In order to measure activation efficiency, all materials were characterized for their properties and ability to remediate two well-known heavy metals of concern: copper and arsenic. Base activated biochars were superior in arsenic adsorption, to acid or steam activated samples, but increase in adsorption was not significant to warrant use. For wood biochars, significant increases of surface functionality as related to oxygen bearing groups and surface charge were observed upon acid activation which led to increased copper ion adsorption. However, oxygen bearing functionalities were not sufficient to explain why chicken litter biochars and steam activated biochars appeared to be significantly superior to wood shavings in positively charged metal ion adsorption. For chicken litter, functionality of respective biochars could be related to phosphate containing groups inherited from feedstock composition, favorably positioning this feedstock in metal ion remediation applications.

Effect of heavy metals on soil enzyme activity at different field conditions in Middle Spis mining area (Slovakia).

Science.gov (United States)

Angelovičová, Lenka; Lodenius, Martin; Tulisalo, Esa; Fazekašová, Danica

2014-12-01

Heavy metals concentrations were measured in the former mining area located in Hornad river valley (Slovakia). Soil samples were taken in 2012 from 20 sites at two field types (grasslands, heaps of waste material) and two different areas. Total content of heavy metals (Cu, Pb, Zn, Hg), urease (URE), acid phosphatase (ACP), alkaline phosphatase (ALP), soil reaction (pH) were changing depending on the field/area type. The tailing pond and processing plants have been found as the biggest sources of pollution. URE, ACP and ALP activities significantly decreased while the heavy metal contents increased. Significant differences were found among area types in the heavy metal contents and activity of URE. No statistical differences in the content of heavy metals but significant statistical differences for soil pH were found for field types (grassland and heaps). Significant negative correlation was found for URE-Pb, URE-Zn and also between soil reaction and ACP and ALP.

Removal effectiveness and mechanisms of naphthalene and heavy metals from artificially contaminated soil by iron chelate-activated persulfate

International Nuclear Information System (INIS)

Yan, Dickson Y.S.; Lo, Irene M.C.

2013-01-01

The effectiveness and mechanisms of naphthalene and metal removal from artificially contaminated soil by FeEDTA/FeEDDS-activated persulfate were investigated through batch experiments. Using FeEDTA-activated persulfate, higher naphthalene removal from the soil at 7 h was achieved (89%), compared with FeEDDS-activated persulfate (75%). The removal was mainly via the dissolution of naphthalene partitioned on mineral surfaces, followed by activated persulfate oxidation. Although EDDS is advantageous over EDTA in terms of biodegradability, it is not preferable for iron chelate-activated persulfate oxidation since persulfate was consumed to oxidize EDDS, resulting in persulfate inadequacy for naphthalene oxidation. Besides, 55 and 40% of naphthalene were removed by FeEDTA and FeEDDS alone, respectively. Particularly, 21 and 9% of naphthalene were degraded in the presence of FeEDTA and FeEDDS alone, respectively, which caused by electrons transfer among dissolved organic matter, Fe 2+ /Fe 3+ and naphthalene. Over 35, 36 and 45% of Cu, Pb and Zn were removed using FeEDTA/FeEDDS-activated persulfate. -- Highlights: ► FeEDTA/FeEDDS-activated persulfate oxidation removed PAH and heavy metal from soil. ► More naphthalene was removed by FeEDTA-activated persulfate compared to FeEDDS. ► Persulfate was consumed to oxidize EDDS in FeEDDS-activated persulfate oxidation. ► Metals can be extracted from soil by free EDTA/EDDS dissociated from FeEDTA/FeEDDS. ► Naphthalene oxidation can be induced by e − transfer among Fe 2+ , DOM and naphthalene. -- This study focuses on the potencies and mechanisms of naphthalene and metal removal from contaminated soil by FeEDTA/FeEDDS-activated persulfate

Reactive oxygen species-related activities of nano-iron metal and nano-iron oxides.

Science.gov (United States)

Wu, Haohao; Yin, Jun-Jie; Wamer, Wayne G; Zeng, Mingyong; Lo, Y Martin

2014-03-01

Nano-iron metal and nano-iron oxides are among the most widely used engineered and naturally occurring nanostructures, and the increasing incidence of biological exposure to these nanostructures has raised concerns about their biotoxicity. Reactive oxygen species (ROS)-induced oxidative stress is one of the most accepted toxic mechanisms and, in the past decades, considerable efforts have been made to investigate the ROS-related activities of iron nanostructures. In this review, we summarize activities of nano-iron metal and nano-iron oxides in ROS-related redox processes, addressing in detail the known homogeneous and heterogeneous redox mechanisms involved in these processes, intrinsic ROS-related properties of iron nanostructures (chemical composition, particle size, and crystalline phase), and ROS-related bio-microenvironmental factors, including physiological pH and buffers, biogenic reducing agents, and other organic substances. Copyright © 2014. Published by Elsevier B.V.

Synthesis, characterization and photocatalytic activity of noble metal-modified TiO2 nanosheets with exposed {0 0 1} facets

International Nuclear Information System (INIS)

Diak, Magdalena; Grabowska, Ewelina; Zaleska, Adriana

2015-01-01

Graphical abstract: - Highlights: • TiO 2 nanosheets with exposed {0 0 1} facets were prepared by hydrothermal method. • Pd and Ag NPs-loaded enhanced the photocatalytic activity under visible irradiation. • Photodeposition is an effective method to obtain noble metal NPs on TiO 2 surface. - Abstract: Pt, Pd, Ag and Au nanoparticles were photodeposited on the {0 0 1} crystal facets of the TiO 2 anatase nanosheets. Morphological and surface characterization of the samples as well as photocatalytic activity were studied. The influence of metal precursor concentration used during photodeposition (0.05−0.5%) on size of formed metal nanoparticles together with UV and vis-mediated activity of Pt, Pd, Ag or Au−TiO 2 was investigated. Generally, samples obtained by photodeposition of noble metal nanoparticles using their 0.2% precursor solutions revealed highest activity in phenol degradation reaction under visible light (λ > 420 nm). The photoactivity of the as-prepared samples with respect to the modified metal species was ordered Ag≅Pd > Au > Pt. TEM analysis showed that photodeposited metal nanoparticles appeared only on {0 0 1} facets of TiO 2 . The average degradation rate of phenol in the presence of Pd and Ag−TiO 2 was 0.5 μmol dm −3 min −1 after 60 min of irradiation under visible light, and was five times higher than that of pure TiO 2 nanosheets

Evaluation of removal efficiency of heavy metals by low-cost activated carbon prepared from African palm fruit

Science.gov (United States)

Abdulrazak, Sani; Hussaini, K.; Sani, H. M.

2017-10-01

This study details the removal of heavy metals; Cadmium, Copper, Nickel, and Lead from wastewater effluent using an activated carbon produced from African palm fruit. The effluent was obtained from Old Panteka market; a metal scrap Market located in Kaduna State, Nigeria, which has several components that constitute high level of pollution in the environment. The effect of temperature and contact time on the removal of these heavy metals using the activated carbon produced was investigated. The activated carbon showed a significant ability in removing heavy metals; Cadmium, Copper, Nickel, and Lead from the wastewater. Higher percentage removal was observed at a temperature of 80 °C (93.23 ± 0.035, 96.71 ± 0.097, 92.01 ± 0.018, and 95.42 ± 0.067 % for Cadmium, Copper, Nickel, and Lead, respectively) and at an optimum contact time of 60 min (99.235 ± 0.148, 96.711 ± 0.083, 95.34 ± 0.015, and 97.750 ± 0.166 % for Cadmium, Copper, Nickel, and Lead, respectively) after which the percentage removal decreases. This work, therefore, suggests that African palm fruit can be successfully applied to solve this environmental pollution.

Cumulative impacts of human activities on urban garden soils: Origin and accumulation of metals

International Nuclear Information System (INIS)

Szolnoki, Zs.; Farsang, A.; Puskás, I.

2013-01-01

The concentration of heavy metals and soil properties in fifty urban garden soils of Szeged (SE Hungary) were determined to evaluate the cumulative impacts of urbanization and cultivation on these soils. Using two enrichment factors (EFs) (based on reference horizon; Ti as reference element) and multivariate statistical analysis (PCA), the origin of the studied elements was defined. According to statistical coincidence of EFs confirmed by t-test, anthropogenic enrichment of Cu (EF = 4), Zn (EF = 2.7) and Pb (EF = 2.5) was significant in topsoils. Moreover, PCA also revealed the geogenic origin of Ni, Co, Cr and As and differentiated two groups of the anthropogenic metals [Pb, Zn] [Cu]. Spatial distribution of the metals visualized by GIS reflected the traffic origin of Pb; while based on ANOVA, the anthropogenic source of Cu is relevant (mainly pesticides) and there is a statistically significant difference in its concentration depending on land use. -- Highlights: ► We determined heavy metal concentrations in urban garden soils of Szeged, Hungary. ► We used different statistical methods, enrichment factors to identify metal origin. ► Enrichment degree and sources of anthropogenic metals were successfully evaluated. ► Anthropogenic enrichment of Cu, Pb and Zn was significant in urban garden topsoils. ► Traffic emission and soil cultivation together are responsible for metal enrichment. -- Metal enrichment and sources in urban garden soils due to urban activities and cultivation were successfully identified by combining more methods (enrichment factors, statistical analysis, spatial distribution)

Mutational analysis of divalent metal ion binding in the active site of class II α-mannosidase from sulfolobus solfataricus

DEFF Research Database (Denmark)

Hansen, Dennis K.; Webb, Helen; Nielsen, Jonas Willum

2015-01-01

Mutational analysis of Sulfolobus solfataricus class II α-mannosidase was focused on side chains that interact with the hydroxyls of the-1 mannosyl of the substrate (Asp-534) or form ligands to the active site divalent metal ion (His-228 and His-533) judged from crystal structures of homologous e......, although less dramatically with some activating metal ions. No major differences in the pH dependence between wild-type and mutant enzymes were found in the presence of different metal ions. The pH optimum was 5, but enzyme instability was observed at pH...

Mycorrhizal fungi modulate phytochemical production and antioxidant activity of Cichorium intybus L. (Asteraceae) under metal toxicity.

Science.gov (United States)

Rozpądek, P; Wężowicz, K; Stojakowska, A; Malarz, J; Surówka, E; Sobczyk, Ł; Anielska, T; Ważny, R; Miszalski, Z; Turnau, K

2014-10-01

Cichorium intybus (common chicory), a perennial plant, common in anthropogenic sites, has been the object of a multitude of studies in recent years due to its high content of antioxidants utilized in pharmacy and food industry. Here, the role of arbuscular mycorrhizal fungi (AMF) in the biosynthesis of plant secondary metabolites and the activity of enzymatic antioxidants under toxic metal stress was studied. Plants inoculated with Rhizophagus irregularis and non-inoculated were grown on non-polluted and toxic metal enriched substrata. The results presented here indicate that AMF improves chicory fitness. Fresh and dry weight was found to be severely affected by the fungi and heavy metals. The concentration of hydroxycinnamates was increased in the shoots of mycorrhizal plants cultivated on non-polluted substrata, but no differences were found in plants cultivated on metal enriched substrata. The activity of SOD and H2O2 removing enzymes CAT and POX was elevated in the shoots of mycorrhizal plants regardless of the cultivation environment. Photochemical efficiency of inoculated chicory was significantly improved. Our results indicate that R. irregularis inoculation had a beneficial role in sustaining the plants ability to cope with the deleterious effects of metal toxicity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Visible light active TiO2 films prepared by electron beam deposition of noble metals

International Nuclear Information System (INIS)

Hou Xinggang; Ma Jun; Liu Andong; Li Dejun; Huang Meidong; Deng Xiangyun

2010-01-01

TiO 2 films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO 2 films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO 2 is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO 2 films by this method is affected by the concentration of impregnating solution.

Sequence of ligand binding and structure change in the diphtheria toxin repressor upon activation by divalent transition metals.

Science.gov (United States)

Rangachari, Vijayaraghavan; Marin, Vedrana; Bienkiewicz, Ewa A; Semavina, Maria; Guerrero, Luis; Love, John F; Murphy, John R; Logan, Timothy M

2005-04-19

The diphtheria toxin repressor (DtxR) is an Fe(II)-activated transcriptional regulator of iron homeostatic and virulence genes in Corynebacterium diphtheriae. DtxR is a two-domain protein that contains two structurally and functionally distinct metal binding sites. Here, we investigate the molecular steps associated with activation by Ni(II)Cl(2) and Cd(II)Cl(2). Equilibrium binding energetics for Ni(II) were obtained from isothermal titration calorimetry, indicating apparent metal dissociation constants of 0.2 and 1.7 microM for two independent sites. The binding isotherms for Ni(II) and Cd(II) exhibited a characteristic exothermic-endothermic pattern that was used to infer the metal binding sequence by comparing the wild-type isotherm with those of several binding site mutants. These data were complemented by measuring the distance between specific backbone amide nitrogens and the first equivalent of metal through heteronuclear NMR relaxation measurements. Previous studies indicated that metal binding affects a disordered to ordered transition in the metal binding domain. The coupling between metal binding and structure change was investigated using near-UV circular dichroism spectroscopy. Together, the data show that the first equivalent of metal is bound by the primary metal binding site. This binding orients the DNA binding helices and begins to fold the N-terminal domain. Subsequent binding at the ancillary site completes the folding of this domain and formation of the dimer interface. This model is used to explain the behavior of several mutants.

Distribution and Identification of Sources of Heavy Metals in the Voghji River Basin Impacted by Mining Activities (Armenia

Directory of Open Access Journals (Sweden)

A. V. Gabrielyan

2018-01-01

Full Text Available The objective of this research is to assess the distribution of heavy metals in the waters and sediments of the Voghji River and its tributaries impacted by mining activity and to reveal the real source of each of the heavy metals in the environment for assessing the pollution level of heavy metals. Voghji River with two main tributaries (Geghi and Norashenik drain two mining regions. To identify distribution and pollution sources of heavy metals, the water and sediment samples were collected from eight sampling sites. The results of statistical analysis based on data sets of the period 2014–2016 showed that, after the influence of drainage water and wastewater of mining regions, heavy metal contents in the Voghji River basin dramatically increased. The waters of the Voghji River were highly polluted by Mn, Co, Cu, Zn, Mo, Cd, and Pb. The relation of metals content was highly changed due to anthropogenic impact disturbing the geochemical balance of the Voghji River. The water quality based on only heavy metal contents in the source of the Voghji River belongs to “good” chemical status, and in the sources of Geghi and Norashenik Rivers it is “moderate.” The water quality of Voghji and Norashenik Rivers is sharply worsening after the influence of mining activity, becoming “bad” chemical status. The research revealed the pollution sources of each metal.

The inhibitory effect of metals and other ions on acid phosphatase activity from Vigna aconitifolia seeds.

Science.gov (United States)

Srivastava, Pramod Kumar; Anand, Asha

2015-01-01

Sensitivity of acid phosphatase from Vigna aconitifolia seeds to metal ions, fluoride, and phosphate was examined. All the effectors had different degree of inhibitory effect on the enzyme. Among metal ions, molybdate and ferric ion were observed to be most potent inhibitors and both exhibited mixed type of inhibition. Acid phosphatase activity was inhibited by Cu2+ in a noncompetitive manner. Zn and Mn showed mild inhibition on the enzyme activity. Inhibition kinetics analysis explored molybdate as a potent inhibitor for acid phosphatase in comparison with other effectors used in this study. Fluoride was the next most strong inhibitor for the enzyme activity, and caused a mixed type of inhibition. Phosphate inhibited the enzyme competitively, which demonstrates that inhibition due to phosphate is one of the regulatory factors for enzyme activity.

Tratamiento de desechos líquidos tóxicos de una industria de recubrimiento metálico por precipitación e intercambio iónico

Directory of Open Access Journals (Sweden)

Katiuska Ramos

2008-12-01

Full Text Available This work presents the results of the treatment of liquid wastes with high content of toxic metals and anions (SO42-, PO43-, F- y NO3-, originated from an industry of anticorrosive covering of metallic parts. Chemical precipitation with lime was applied, obtaining percentage of removal, for metals and phosphate, higher than 98%, being those samples within unloading parameters. For the rest of anions, ion exchange was applied obtaining percentages of removal for sulfate of 97%, nitrate 99% and fluoride 71%. In spite of the effectiveness of both treatments, by-products are generated that require of a suitable final disposition.

Heavy metal pollution decreases microbial abundance, diversity and activity within particle-size fractions of a paddy soil.

Science.gov (United States)

Chen, Junhui; He, Feng; Zhang, Xuhui; Sun, Xuan; Zheng, Jufeng; Zheng, Jinwei

2014-01-01

Chemical and microbial characterisations of particle-size fractions (PSFs) from a rice paddy soil subjected to long-term heavy metal pollution (P) and nonpolluted (NP) soil were performed to investigate whether the distribution of heavy metals (Cd, Cu, Pb and Zn) regulates microbial community activity, abundance and diversity at the microenvironment scale. The soils were physically fractionated into coarse sand, fine sand, silt and clay fractions. Long-term heavy metal pollution notably decreased soil basal respiration (a measurement of the total activity of the soil microbial community) and microbial biomass carbon (MBC) across the fractions by 3-45% and 21-53%, respectively. The coarse sand fraction was more affected by pollution than the clay fraction and displayed a significantly lower MBC content and respiration and dehydrogenase activity compared with the nonpolluted soils. The abundances and diversities of bacteria were less affected within the PSFs under pollution. However, significant decreases in the abundances and diversities of fungi were noted, which may have strongly contributed to the decrease in MBC. Sequencing of denaturing gradient gel electrophoresis bands revealed that the groups Acidobacteria, Ascomycota and Chytridiomycota were clearly inhibited under pollution. Our findings suggest that long-term heavy metal pollution decreased the microbial biomass, activity and diversity in PSFs, particularly in the large-size fractions. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Antifungal activity of water-stable copper-containing metal-organic frameworks

Science.gov (United States)

Bouson, Supaporn; Krittayavathananon, Atiweena; Phattharasupakun, Nutthaphon; Siwayaprahm, Patcharaporn; Sawangphruk, Montree

2017-10-01

Although metal-organic frameworks (MOFs) or porous coordination polymers have been widely studied, their antimicrobial activities have not yet been fully investigated. In this work, antifungal activity of copper-based benzene-tricarboxylate MOF (Cu-BTC MOF), which is water stable and industrially interesting, is investigated against Candida albicans, Aspergillus niger, Aspergillus oryzae and Fusarium oxysporum. The Cu-BTC MOF can effectively inhibit the growth rate of C. albicans and remarkably inhibit the spore growth of A. niger, A. oryzae and F. oxysporum. This finding shows the potential of using Cu-BTC MOF as a strong biocidal material against representative yeasts and moulds that are commonly found in the food and agricultural industries.

MECHANISMS OF THE COMPLEX FORMATION BY d-METALS ON POROUS SUPPORTS AND THE CATALYTIC ACTIVITY OF THE FORMED COMPLEXES IN REDOX REACTIONS

Directory of Open Access Journals (Sweden)

T. L. Rakitskaya

2015-11-01

Full Text Available The catalytic activity of supported complexes of d metals in redox reactions with participation of gaseous toxicants, PH3, CO, O3, and SO2, depends on their composition. Owing to the variety of physicochemical and structural-adsorption properties of available supports, their influence on complex formation processes, the composition and catalytic activity of metal complexes anchored on them varies over a wide range. The metal complex formation on sup-ports with weak ion-exchanging properties is similar to that in aqueous solutions. In this case, the support role mainly adds up to the ability to reduce the activity of water adsorbed on them. The interaction between a metal complex and a support surface occurs through adsorbed water molecules. Such supports can also affect complex formation processes owing to protolytic reactions on account of acidic properties of sorbents used as supports. The catalytic activity of metal complexes supported on polyphase natural sorbents considerably depends on their phase relationship. In the case of supports with the nonsimple structure and pronounced ion-exchanging properties, for instance, zeolites and laminar silicates, it is necessary to take into account the variety of places where metal ions can be located. Such location places determine distinctions in the coordination environment of the metal ions and the strength of their bonding with surface adsorption sites and, therefore, the catalytic activity of surface complexes formed by theses metal ions. Because of the energy surface inhomogeneity, it is important to determine a relationship between the strength of a metal complex bonding with a support surface and its catalytic activity. For example, bimetallic complexes are catalytically active in the reactions of oxidation of the above gaseous toxicants. In particular, in the case of carbon monoxide oxidation, the most catalytic activity is shown by palladium-copper complexes in which copper(II is strongly

Slow and stopped light in active gain composite materials of metal nanoparticles. Ultralarge group index-bandwidth product predicted

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang-Hyon; Choe, Song-Hyok [Institute of Lasers, State Academy of Sciences, Unjong District, Pyongyang (Korea, Democratic People' s Republic of)

2017-08-15

Chip-compatible slow light devices with large group index-bandwidth products and low losses are of great interest in the community of modern photonics. In this work, active gain materials containing metal nanoparticles are proposed as the slow and stopped light materials. Gain-assisted high field enhancement in metal nanoparticles and the resultant strong dispersion lead to such phenomena. From the Maxwell-Garnett model, it is revealed that the metal nanocomposite exhibits the infinitely large group index when the gain of the host medium and the filling factor of metal nanoparticles satisfy a critical condition. For the gain of the host above the critical value, one can observe slowing down effect with amplification of light pulses. Significantly large group index-bandwidth products, which vary from a few to several thousand or even infinity depending on the gain value of the host medium, have been numerically predicted in active silica glasses containing spheroidal metal nanoparticles, as examples. The proposed scheme inherently provides the widely varying operating spectral range by changing the aspect ratio of metal nanoparticles and chip-compatibility with low cost. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Metal-containing Complexes of Lactams, Imidazoles, and Benzimidazoles and Their Biological Activity

Science.gov (United States)

Kukalenko, S. S.; Bovykin, B. A.; Shestakova, S. I.; Omel'chenko, A. M.

1985-07-01

The results of the latest investigations of the problem of the synthesis of metal-containing complexes of lactams, imidazoles, and benzimidazoles, their structure, and their stability in solutions are surveyed. Some data on their biological activity (pesticide and pharmacological) and the mechanism of their physiological action are presented. The bibliography includes 190 references.

Activation analysis of trace metals in several kinds of tissues of even-toed ungulates

International Nuclear Information System (INIS)

Fukushima, M.; Tamate, H.; Sato, S.; Terui, S.; Mitsugashira, T.

1999-01-01

The normal concentration levels of trace metals in several kinds of tissues of even-toed ungulates have been determined by instrumental neutron activation analysis, photon activation analysis, and flame atomic absorption spectrometry. In the present work the concentrations of 13 elements (Ag, Br, Ca, Co, Cu, Fe, Mg, Mn, Mo, Na, Rb, Se, and Zn) were analyzed. (author)

Soil heavy metals

Energy Technology Data Exchange (ETDEWEB)

Sherameti, Irena [Jena Univ. (Germany). Inst. fuer Allgemeine Botanik und Pflanzenphysiologie; Varma, Ajit (eds.) [Amity Univ., Uttar Pradesh (India). Amity Inst. of Microbial Technology; Amity Science, Technology and Innovation Foundation, Noida, UP (India)

2010-07-01

Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume. The topics presented include: the general role of heavy metals in biological soil systems; the relation of inorganic and organic pollutions; heavy metal, salt tolerance and combined effects with salinity; effects on abuscular mycorrhizal and on saprophytic soil fungi; heavy metal resistance by streptomycetes; trace element determination of environmental samples; the use of microbiological communities as indicators; phytostabilization of lead polluted sites by native plants; effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land. (orig.)

Influence of potassium hydroxide activation on characteristics and environmental risk of heavy metals in chars derived from municipal sewage sludge.

Science.gov (United States)

Li, Zhengjia; Deng, Hui; Yang, Le; Zhang, Genlin; Li, Yuqi; Ren, Yansen

2018-05-01

To investigate the influence of KOH activation on characteristics and environmental risk of heavy metals in chars, sludge was pyrolyzed with varying amount of KOH. The analyzation of characteristics and potential ecological risk evaluation of heavy metals were conducted by surface area analyzer, FTIR, XRD and BCR sequential extraction. The activated chars have higher surface area and lower content of silica compared to those without being activated. The activation of KOH promoted residual fraction of Cd, meanwhile, Zinc, Cr, Ni and Mn were converted to relatively unstable fractions (F2 and F3). The results of risk assessment indicated that the potential ecological risk level of Cd was reduced in activated chars, while risk level of Zn, Cr, Ni and Mn were increased after pyrolysis with KOH activation. The potential ecological risk of heavy metals in activated chars was further declined, and the risk level transformed from moderate to low. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influence of the metal ion on the enzyme activity and kinetics of PepA from Lactobacillus delbrueckii.

Science.gov (United States)

Ewert, Jacob; Glück, Claudia; Strasdeit, Henry; Fischer, Lutz; Stressler, Timo

2018-03-01

The aminopeptidase A (PepA; EC 3.4.11.7) belongs to the group of metallopeptidases with two bound metal ions per subunit (M1M2(PepA)) and is specific for the cleavage of N-terminal glutamic (Glu) and aspartic acid (Asp) and, in low amounts, serine (Ser) residues. Our group recently characterized the first PepA from a Lactobacillus strain. However, the characterization was performed using synthetic para-nitroaniline substrates and not original peptide substrates, as was done in the current study. Prior to the characterization using original peptide substrates, the PepA purified was converted to its inactive apo-form and eight different metal ions were tested to restore its activity. It was found that five of the metal ions were able to reactivate apo-PepA: Co 2+ , Cu 2+ , Mn 2+ , Ni 2+ and Zn 2+ . Interestingly, depending on the metal ion used for reactivation, the activity and the pH and temperature profile differed. Exemplarily, MnMn(PepA), NiNi(PepA) and ZnZn(PepA) had an activity optimum using MES buffer (50mM, pH 6.0) and 60°C, whereas the activity optimum changed to Na/K-phosphate-buffer (50mM, pH 7.0) and 55°C for CuCu(PepA). However, more important than the changes in optimum pH and temperature, the kinetic properties of PepA were affected by the metal ion used. While all PepA variants could release N-terminal Glu or Asp, only CoCo(PepA), NiNi(PepA) and CuCu(PepA) could release Ser from the particular peptide substrate. In addition, it was found that the enzyme efficiency (V max /K M ) and catalytic mechanism (positive cooperative binding (Hill coefficent; n), substrate inhibition (K IS )) were influenced by the metal ion. Exemplarily, a high cooperativity (n>2),K IS value >20mM and preference for N-terminal Glu were detected for CuCu(PepA). In summary, the results suggested that an exchange of the metal ion can be used for tailoring the properties of PepA for specific hydrolysis requirements. Copyright © 2017 Elsevier Inc. All rights reserved.

Tuning metal support interactions enhances the activity and durability of TiO2-supported Pt nanocatalysts

International Nuclear Information System (INIS)

Hsieh, Bing-Jen; Tsai, Meng-Che; Pan, Chun-Jern; Su, Wei-Nien; Rick, John; Chou, Hung-Lung; Lee, Jyh-Fu; Hwang, Bing-Joe

2017-01-01

Highlights: • The coverage of TiO x on Pt can be modified by thermal and fluoric acid treatments. • Strong metal support interaction (SMSI) can be testified by electrochemical method. • For the first time, the SMSI effect is observed at 200 °C with supporting TEM images. • Increased activity and stability are attributed to stronger SMSI. • This tunable approach is valid for other oxide supported catalysts, e.g. Pt/Nb-TiO 2 . - Abstract: A facile approach to enhance catalytic activity and durability of TiO 2 -supported Pt nanocatalysts by tuning strong metal support interaction (SMSI) is investigated in this work. No need for a high temperature treatment, the strong metal-support interaction (SMSI) in TiO 2 -supported Pt can be induced at 200° C by H 2 reduction. Moreover, electrochemical methods (methanol oxidation reaction and cyclic voltammetry) are first reported ever to be effective characterization tools for the coverage state caused by SMSI. In addition, the SMSI has also been confirmed by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and Transmission Electron Microscopy. It is found that the encapsulation of TiO 2-x species on the surface Pt clusters was induced and modified by thermal reduction and fluoric acid treatment. The catalytic activity and durability of the TiO 2 -supported Pt nanocatalysts are strongly dependent of the state of SMSI. The proposed SMSI-tunable approach to enhance the ORR activity and stability is also proved applicable to Pt/Ti 0.9 Nb 0.1 O 2 nanocatalysts. We believe that the reported approach paves the way for manipulating the activity and stability of other TiO 2 -supported metal nanocatalysts. Furthermore, the suggested electrochemical methods offer facile and effective ways to verify the presence of coverage state before combining with other physical analysis.

Double C-H activation of ethane by metal-free SO2*+ radical cations.

Science.gov (United States)

de Petris, Giulia; Cartoni, Antonella; Troiani, Anna; Barone, Vincenzo; Cimino, Paola; Angelini, Giancarlo; Ursini, Ornella

2010-06-01

The room-temperature C-H activation of ethane by metal-free SO(2)(*+) radical cations has been investigated under different pressure regimes by mass spectrometric techniques. The major reaction channel is the conversion of ethane to ethylene accompanied by the formation of H(2)SO(2)(*+), the radical cation of sulfoxylic acid. The mechanism of the double C-H activation, in the absence of the single activation product HSO(2)(+), is elucidated by kinetic studies and quantum chemical calculations. Under near single-collision conditions the reaction occurs with rate constant k=1.0 x 10(-9) (+/-30%) cm(3) s(-1) molecule(-1), efficiency=90%, kinetic isotope effect k(H)/k(D)=1.1, and partial H/D scrambling. The theoretical analysis shows that the interaction of SO(2)(*+) with ethane through an oxygen atom directly leads to the C-H activation intermediate. The interaction through sulfur leads to an encounter complex that rapidly converts to the same intermediate. The double C-H activation occurs by a reaction path that lies below the reactants and involves intermediates separated by very low energy barriers, which include a complex of the ethyl cation suitable to undergo H/D scrambling. Key issues in the observed reactivity are electron-transfer processes, in which a crucial role is played by geometrical constraints. The work shows how mechanistic details disclosed by the reactions of metal-free electrophiles may contribute to the current understanding of the C-H activation of ethane.

Metal-organic cooperative catalysis in C-H and C-C bond activation and its concurrent recovery.

Science.gov (United States)

Park, Young Jun; Park, Jung-Woo; Jun, Chul-Ho

2008-02-01

The development of an efficient catalytic activation (cleavage) system for C-H and C-C bonds is an important challenge in organic synthesis, because these bonds comprise a variety of organic molecules such as natural products, petroleum oils, and polymers on the earth. Among many elegant approaches utilizing transition metals to activate C-H and C-C bonds facilely, chelation-assisted protocols based on the coordinating ability of an organic moiety have attracted great attention, though they have often suffered from the need for an intact coordinating group in a substrate. In this Account, we describe our entire efforts to activate C-H or C-C bonds adjacent to carbonyl groups by employing a new concept of metal-organic cooperative catalysis (MOCC), which enables the temporal installation of a 2-aminopyridyl group into common aldehydes or ketones in a catalytic way. Consequently, a series of new catalytic reactions such as alcohol hydroacylation, oxo-ester synthesis, C-C triple bond cleavage, hydrative dimerization of alkynes, and skeletal rearrangements of cyclic ketones was realized through MOCC. In particular, in the quest for an optimized MOCC system composed of a Wilkinson's catalyst (Ph 3P) 3RhCl and an organic catalyst (2-amino-3-picoline), surprising efficiency enhancements could be achieved when benzoic acid and aniline were introduced as promoters for the aldimine formation process. Furthermore, a notable accomplishment of C-C bond activation has been made using 2-amino-3-picoline as a temporary chelating auxiliary in the reactions of unstrained ketones with various terminal olefins and Wilkinson's catalyst. In the case of seven-membered cyclic ketones, an interesting ring contraction to five- or six-membered ones takes place through skeletal rearrangements initiated by the C-C bond activation of MOCC. On the other hand, the fundamental advances of these catalytic systems into recyclable processes could be achieved by immobilizing both metal and organic

Selective metallization of polymers using laser induced surface activation (LISA)—characterization and optimization of porous surface topography

DEFF Research Database (Denmark)

Zhang, Yang; Hansen, Hans Nørgaard; De Grave, Arnaud

2011-01-01

Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was perfor...

Novel Metals and Metal Complexes as Platforms for Cancer Therapy

OpenAIRE

Frezza, Michael; Hindo, Sarmad; Chen, Di; Davenport, Andrew; Schmitt, Sara; Tomco, Dajena; Dou, Q. Ping

2010-01-01

Metals are essential cellular components selected by nature to function in several indispensable biochemical processes for living organisms. Metals are endowed with unique characteristics that include redox activity, variable coordination modes, and reactivity towards organic substrates. Due to their reactivity, metals are tightly regulated under normal conditions and aberrant metal ion concentrations are associated with various pathological disorders, including cancer. For these reasons, coo...

Physicochemical properties of metal-doped activated carbons and relationship with their performance in the removal of SO{sub 2} and NO

Energy Technology Data Exchange (ETDEWEB)

Gao Xiang, E-mail: xgao1@zju.edu.cn [State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Liu Shaojun; Zhang Yang; Luo Zhongyang; Cen Kefa [State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China)

2011-04-15

Research highlights: {yields} Cu and Fe were partly reduced by carbon during preparation. {yields} Metal-involved SO{sub 2} removal pathways were catalytic oxidation, reaction and adsorption. {yields} Good performances of SO{sub 2} and NO removal depended on the metal redox pairs. - Abstract: Several metal-doped activated carbons (Fe, Co, Ni, V, Mn, Cu and Ce) were prepared and characterized. The results of N{sub 2} adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy indicated that some metals (Cu and Fe) were partly reduced by carbon during preparation. Activity tests for the removal of SO{sub 2} and the selective catalytic reduction of NO with ammonia were carried out. Due to different physicochemical properties, different pathways for the SO{sub 2} removal had been put out, i.e., catalytic oxidation, direct reaction and adsorption. This classification depended on the standard reduction potentials of metal redox pairs. Samples impregnated with V, Ce and Cu showed good activity for NO reduction by NH{sub 3}, which was also ascribed to the reduction potential values of metal redox pairs. Ce seemed to be a promising alternative to V due to the higher activity in NO reduction and the nontoxic property. A metal cation which could easily convert between the two valences seemed to be crucial to the good performance of both SO{sub 2} and NO removal, just like V and Cu.

Soil microbial activity, mycelial lengths and physiological groups of bacteria in a heavy metal polluted area

Energy Technology Data Exchange (ETDEWEB)

Nordgren, A; Kauri, T; Baeaeth, E; Soederstroem, B

1986-01-01

The biological effects of heavy metal contamination of coniferous forest soils were studied in the A/sub 01//A/sub 02/ layer around a primary smelter in Northern Sweden. Soil concentrations of 17 elements were determined. Smelter-emitted heavy metals were 5 to 75 times higher in the plot closest to the smelter compared with background levels. Despite emission of sulfur no decrease in pH was found. Bacteria producing acid from maltose, cellobiose, arabinose or xylose and bacteria hydrolyzing starch, pectin, xyland or cellulose decreased 8- to 11-fold due to the soil contamination. Chitin hydrolyzers were 5 times less abundant at the most polluted site compared with background levels. Soil respiration rate and urease activity decreased by about a factor of 4, but phosphatase activity and mycelial lengths were unaffected by the soil contamination. Soil bacteria showed a sigmoidal response to the log of metal concentration in the soil and were affected at a lower pollution level than the other biological variables in the study. A multivariate analysis (partial least squares) showed that soil metal contamination and soil pH were the two environmental factors influencing the soil microorganisms.

Rapidly assessing the activation conditions and porosity of metal-organic frameworks using thermogravimetric analysis.

Science.gov (United States)

McDonald, Thomas M; Bloch, Eric D; Long, Jeffrey R

2015-03-25

A methodology utilizing a thermogravimetric analyzer to monitor propane uptake following incremental increases of the temperature is demonstrated as a means of rapidly identifying porous materials and determining the optimum activation conditions of metal-organic frameworks.

Cupryphans, metal-binding, redox-active, redesigned conopeptides.

Science.gov (United States)

Barba, Marco; Sobolev, Anatoli P; Romeo, Cristina; Schininà, M Eugenia; Pietraforte, Donatella; Mannina, Luisa; Musci, Giovanni; Polticelli, Fabio

2009-03-01

Contryphans are bioactive peptides, isolated from the venom of marine snails of the genus Conus, which are characterized by the short length of the polypeptide chain and the high degree of unusual post-translational modifications. The cyclization of the polypeptide chain through a single disulphide bond, the presence of two conserved Pro residues, and the epimerization of a Trp/Leu residue confer to Contryphans a stable and well-defined structure in solution, conserved in all members of the family, and tolerant to multiple substitutions. The potential of Contryphans as scaffolds for the design of redox-active (macro)molecules was tested by engineering a copper-binding site on two different variants of the natural peptide Contryphan-Vn. The binding site was designed by computational modeling, and the redesigned peptides were synthesized and characterized by optical, fluorescence, electron spin resonance, and nuclear magnetic resonance spectroscopy. The novel peptides, named Cupryphan and Arg-Cupryphan, bind Cu(2+) ions with a 1:1 stoichiometry and a K(d) in the 100 nM range. Other divalent metals (e.g., Zn(2+) and Mg(2+)) are bound with much lower affinity. In addition, Cupryphans catalyze the dismutation of superoxide anions with an activity comparable to other nonpeptidic superoxide dismutase mimics. We conclude that the Contryphan motif represents a natural robust scaffold which can be engineered to perform different functions, providing additional means for the design of catalytically active mini metalloproteins.

Synthesis, Characterization and Antimicrobial Activities of Transition Metal Complexes of methyl 2-(((E)-(2-hydroxyphenyl)methylidene)amino)benzoate

International Nuclear Information System (INIS)

Ikram, M.; Rehman, S.

2016-01-01

New metal complexes with Schiff base ligand methyl 2-(((E)-(2-hydroxyphenyl)methylidene)amino)benzoate, were synthesized and characterized. Elemental analyses, EI-MS, 1H and 13C(1H)-NMR were used for ligand characterization whereas elemental analyses, EI-MS, IR and UV-Visible spectroscopic techniques were used for the transition metal compounds. All these analyses reveal the bis arrangement of the ligand around the metal centres. The compounds were studied for their antimicrobial activities against different pathogenic microbial species. It was found that the Schiff base ligand was completely inactive in comparison to the transition metal compounds. It was also observed that nickel based metal complex shown good results against Candida albican (25 mm) and zinc based metal complex against Agrobacterium tumefaciens (16 mm). (author)

Remediation of an acidic mine spoil: Miscanthus biochar and lime amendment affects metal availability, plant growth, and soil enzyme activity.

Science.gov (United States)

Novak, Jeffrey M; Ippolito, James A; Ducey, Thomas F; Watts, Donald W; Spokas, Kurt A; Trippe, Kristin M; Sigua, Gilbert C; Johnson, Mark G

2018-08-01

Biochar may be a tool for mine spoil remediation; however, its mechanisms for achieving this goal remain unclear. In this study, Miscanthus (Miscanthus giganteus) biochar was evaluated for its ability to reclaim acidic mine spoils (pH lime/no lime and fertilizer additions. Blue Wildrye (Elymus glaucus cv. 'Elkton') was planted and later the shoots and roots were collected and metal concentrations determined. Afterwards, each pot was leached with deionized water, and the leachate analyzed for pH, electrical conductivity (EC), dissolved organic carbon (DOC) and soluble metal concentrations. After drying, the spoil was extracted with 0.01 M CaCl 2 and Mehlich 3 (M3) to determine extractable Al, Cu, and Zn concentrations. Additionally, microbial activity was measured using a fluorescent β-glucosidase and N-acetyl-β-d-glucosaminidase assay. Spoil treated with lime and biochar had significantly greater pH and EC values. Significantly greater β-glucosidase activity occurred only in the 5% biochar plus lime treatment, while N-acetyl-β-d-glucosaminidase activities were not altered. Metal concentrations in rye shoot and roots were mixed. Lime additions significantly reduced extractable metal concentrations. Increasing biochar rates alone significantly reduced leachate DOC concentrations, and subsequently reduced leachable metal concentrations. Surprisingly, miscanthus biochar, by itself, was limited at mitigation, but when combined with lime, the combination was capable of further reducing extractable metal concentrations and improving β-glucosidase enzyme activity. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Comparison of the multifractal characteristics of heavy metals in soils within two areas of contrasting economic activities in China

Science.gov (United States)

Li, Xiaohui; Li, Xiangling; Yuan, Feng; Jowitt, Simon M.; Zhou, Taofa; Yang, Kui; Zhou, Jie; Hu, Xunyu; Li, Yang

2016-09-01

Industrial and agricultural activities can generate heavy metal pollution that can cause a number of negative environmental and health impacts. This means that evaluating heavy metal pollution and identifying the sources of these pollutants, especially in urban or developed areas, is an important first step in mitigating the effects of these contaminating but necessary economic activities. Here, we present the results of a heavy metal (Cu, Pb, Zn, Cd, As, and Hg) soil geochemical survey in Hefei city. We used a multifractal spectral technique to identify and compare the multifractality of heavy metal concentrations of soils within the industrial Daxing and agricultural Yicheng areas. This paper uses three multifractal parameters (Δα, Δf(α), and τ''(1)) to indicate the overall amount of multifractality within the soil geochemical data. The results show all of the elements barring Hg have larger Δα, Δf(α), and τ''(1) values in the Daxing area compared to the Yicheng area. The degree of multifractality suggests that the differing economic activities in Daxing and Yicheng generate very different heavy metal pollution loads. In addition, the industrial Daxing area contains significant Pb and Cd soil contamination, whereas Hg is the main heavy metal present in soils within the Yicheng area, indicating that differing clean-up procedures and approaches to remediating these polluted areas are needed. The results also indicate that multifractal modelling and the associated generation of multifractal parameters can be a useful approach in the evaluation of heavy metal pollution in soils.

Activity Descriptors for CO₂ Electroreduction to Methane on Transition-Metal Catalysts

DEFF Research Database (Denmark)

Peterson, Andrew; Nørskov, Jens K.

2012-01-01

The electrochemical reduction of CO2 into hydrocarbons and alcohols would allow renewable energy sources to be converted into fuels and chemicals. However, no electrode catalysts have been developed that can perform this transformation with a low overpotential at reasonable current densities....... In this work, we compare trends in binding energies for the intermediates in CO2 electrochemical reduction and present an activity “volcano” based on this analysis. This analysis describes the experimentally observed variations in transition-metal catalysts, including why copper is the best-known metal...

Individual and cumulative effects of agriculture, forestry and metal mining activities on the metal and phosphorus content of fluvial fine-grained sediment; Quesnel River Basin, British Columbia, Canada.

Science.gov (United States)

Smith, Tyler B; Owens, Philip N

2014-10-15

The impact of agriculture, forestry and metal mining on the quality of fine-grained sediment (sediment were collected monthly during the snow-free season in 2008 using time-integrated samplers at replicate sites representative of agriculture, forestry and mining activities in the basin (i.e. "impacted" sites). Samples were also collected from replicate reference sites and also from the main stem of the Quesnel River at the downstream confluence with the Fraser River. Generally, metal(loid) and phosphorus (P) concentrations for "impacted" sites were greater than for reference sites. Furthermore, concentrations of copper (forestry and mining sites), manganese (agriculture and forestry sites) and selenium (agriculture, forestry and mining sites) exceeded upper sediment quality guideline (SQG) thresholds. These results suggest that agriculture, forestry and metal mining activities are having an influence on the concentrations of sediment-associated metal(loid)s and P in the Quesnel basin. Metal(loid) and P concentrations of sediment collected from the downstream site were not significantly greater than values for the reference sites, and were typically lower than the values for the impacted sites. This suggests that the cumulative effects of agriculture, forestry and mining activities in the QRB are presently not having a measureable effect at the river basin-scale. The lack of a cumulative effect at the basin-scale is thought to reflect: (i) the relatively recent occurrence of land use disturbances in this basin; (ii) the dominance of sediment contributions from natural forest and agriculture; and (iii) the potential for storage of contaminants on floodplains and other storage elements between the locations of disturbance activities and the downstream sampling site, which may be attenuating the disturbance signal. Copyright © 2014 Elsevier B.V. All rights reserved.

EFFECT OF HEAVY METAL IONS ON THE NUMBER AND ACTIVITY OF Azotobacter AND MELANINSYNTHESIZING MICROMYCETES

OpenAIRE

Malynovska I. M.

2017-01-01

The aim of the work was to determine the possibility of using the number and activity of Azotobacter cells and melanin-synthesizing micromycetes as indicators of gray forest soils of different types (fallow, extensive and intensive agrosoil) pollution with heavy metal ions. For this purpose, there were used laboratory-analytical, microbiological and statistical methods. As a result of research of increasing doses of heavy metals (zinc + lead) influence on the number of microorganisms in the g...

Activation analysis for measurements of silicon, phosphorus, alkali metals and other elements in high-purity metals

International Nuclear Information System (INIS)

Schmid, W.

1988-01-01

In the present thesis, methods of activation analysis were developed for the determination of the elements silicon, phosphorus, potassium, sodium, i.a. in the high-purity metals vanadium, niobium, tantalum, tungsten, molybdenum and iron. The determination of silicon is based on the activation of samples with reactor neutrons, on a subsequent radiochemical separation of the tracer radionuclide 31 Si resulting from the reaction 30 Si(n,γ), and on the measurement of β activity with the help of a liquid scintillation measuring desk. Since the tracer radionuclide 31 Si almost exclusively emits β rays which are not sufficiently nuclide-specific, silicon was selectively separated from the other sample elements by being distilled as silicon tetrafluoride. The processing of the residue following the separation of silicon permits a complementary gamma-spectroscopic determination of a whole lot of additional elements. Thus, the separation of the nuclide 182 Ta with the anion exchanger Dowex 1X8 from HF/H 2 SO 4 medium permits the determination of 22 elements in vanadium, niobium and tantalum. Phosphorus content is determined by activating the samples with rapid neutrons (cyclotrons) via the reaction 31 P(n,p) 31 Si. (orig./MM) [de

Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study

Directory of Open Access Journals (Sweden)

Azam A

2012-12-01

Full Text Available Ameer Azam,1,2 Arham S Ahmed,2 Mohammad Oves,3 Mohammad S Khan,3 Sami S Habib,1 Adnan Memic11Centre of Nanotechnology, King Abdulaziz University, Jeddah, Saudi Arabia; 2Centre of Excellence in Materials Science (Nanomaterials, 3Department of Agricultural Microbiology, Aligarh Muslim University, Aligarh, IndiaBackground: Nanomaterials have unique properties compared to their bulk counterparts. For this reason, nanotechnology has attracted a great deal of attention from the scientific community. Metal oxide nanomaterials like ZnO and CuO have been used industrially for several purposes, including cosmetics, paints, plastics, and textiles. A common feature that these nanoparticles exhibit is their antimicrobial behavior against pathogenic bacteria. In this report, we demonstrate the antimicrobial activity of ZnO, CuO, and Fe2O3 nanoparticles against Gram-positive and Gram-negative bacteria.Methods and results: Nanosized particles of three metal oxides (ZnO, CuO, and Fe2O3 were synthesized by a sol–gel combustion route and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy techniques. X-ray diffraction results confirmed the single-phase formation of all three nanomaterials. The particle sizes were observed to be 18, 22, and 28 nm for ZnO, CuO, and Fe2O3, respectively. We used these nanomaterials to evaluate their antibacterial activity against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa and Gram-positive (Staphylococcus aureus and Bacillus subtilis bacteria.Conclusion: Among the three metal oxide nanomaterials, ZnO showed greatest antimicrobial activity against both Gram-positive and Gram-negative bacteria used in this study. It was observed that ZnO nanoparticles have excellent bactericidal potential, while Fe2O3 nanoparticles exhibited the least bactericidal activity. The order of antibacterial activity was demonstrated to be the following: ZnO > CuO > Fe2O3

Remediation Performance and Mechanism of Heavy Metals by a Bottom Up Activation and Extraction System Using Multiple Biochemical Materials.

Science.gov (United States)

Xiao, Kemeng; Li, Yunzhen; Sun, Yang; Liu, Ruyue; Li, Junjie; Zhao, Yun; Xu, Heng

2017-09-13

Soil contamination with heavy metals has caused serious environmental problems and increased the risks to humans and biota. Herein, we developed an effective bottom up metals removal system based on the synergy between the activation of immobilization metal-resistant bacteria and the extraction of bioaccumulator material (Stropharia rugosoannulata). In this system, the advantages of biochar produced at 400 °C and sodium alginate were integrated to immobilize bacteria. Optimized by response surface methodology, the biochar and bacterial suspension were mixed at a ratio of 1:20 (w:v) for 12 h when 2.5% sodium alginate was added to the mixture. Results demonstrated that the system significantly increased the proportion of acid soluble Cd and Cu and improved the soil microecology (microbial counts, soil respiration, and enzyme activities). The maximum extractions of Cd and Cu were 8.79 and 77.92 mg kg -1 , respectively. Moreover, details of the possible mechanistic insight into the metal removal are discussed, which indicate positive correlation with the acetic acid extractable metals and soil microecology. Meanwhile, the "dilution effect" in S. rugosoannulata probably plays an important role in the metal removal process. Furthermore, the metal-resistant bacteria in this system were successfully colonized, and the soil bacteria community were evaluated to understand the microbial diversity in metal-contaminated soil after remediation.

Comparative study of antioxidant, metal chelating and antiglycation activities of Momordica charantia flesh and pulp fractions.

Science.gov (United States)

Ghous, Tahseen; Aziz, Nouman; Mehmood, Zahid; Andleeb, Saiqa

2015-07-01

Momordica charantia is commonly used as a vegetable and folk medicine in most parts of South Asia. This study aims to determine and compare the antioxidant, metal chelating and antiglycation activities of aqueous extracts of M. charantia fruit flesh (MCF) and fruit pulp (MCP) fractions. Our results show that MCP has pronounced DPPH and ABTS radical scavenging potential compared to MCF. In the antiglycation assay both fractions illustrated considerable inhibitory activities against the formation of AGEs induced by glucose with an efficacy of 75 and 67% with 150 μl of MCP and MCF extracts respectively, almost equal to 0.3mM amino guanidine. Results for metal catalysed protein fragmentation and autoxidative and glycoxidation assays demonstrate that MCF and MCP inhibited metal catalysed protein fragmentation. The percentage of relative standard deviation for three replicate measurements of 150 μl of MCF and MCP was < 3.0% for antiglycation. The antioxidant assays with regression values of MCP (0.981 and 0.991) and MCF (0.967 and 0.999) were also recorded. We conclude that both extracts possess high antioxidant and antiglycation activities and are equally good sources of antioxidant and antiglycating agents.

Phytochelatin synthase activity as a marker of metal pollution

Energy Technology Data Exchange (ETDEWEB)

Zitka, Ondrej; Krystofova, Olga; Sobrova, Pavlina [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Adam, Vojtech [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic); Zehnalek, Josef; Beklova, Miroslava [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Kizek, Rene, E-mail: kizek@sci.muni.cz [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic)

2011-08-30

Highlights: {yields} New tool for determination of phytochelatin synthase activity. {yields} The optimization of experimental condition for determination of the enzyme activity. {yields} First evaluation of K{sub m} for the enzyme. {yields} The effects of cadmium (II) not only on the activity of the enzyme but also on K{sub m}. -- Abstract: The synthesis of phytochelatins is catalyzed by {gamma}-Glu-Cys dipeptidyl transpeptidase called phytochelatin synthase (PCS). Aim of this study was to suggest a new tool for determination of phytochelatin synthase activity in the tobacco BY-2 cells treated with different concentrations of the Cd(II). After the optimization steps, an experiment on BY-2 cells exposed to different concentrations of Cd(NO{sub 3}){sub 2} for 3 days was performed. At the end of the experiment, cells were harvested and homogenized. Reduced glutathione and cadmium (II) ions were added to the cell suspension supernatant. These mixtures were incubated at 35 {sup o}C for 30 min and analysed using high performance liquid chromatography coupled with electrochemical detector (HPLC-ED). The results revealed that PCS activity rises markedly with increasing concentration of cadmium (II) ions. The lowest concentration of the toxic metal ions caused almost three fold increase in PCS activity as compared to control samples. The activity of PCS (270 fkat) in treated cells was more than seven times higher in comparison to control ones. K{sub m} for PCS was estimated as 2.3 mM.

Phytochelatin synthase activity as a marker of metal pollution

International Nuclear Information System (INIS)

Zitka, Ondrej; Krystofova, Olga; Sobrova, Pavlina; Adam, Vojtech; Zehnalek, Josef; Beklova, Miroslava; Kizek, Rene

2011-01-01

Highlights: → New tool for determination of phytochelatin synthase activity. → The optimization of experimental condition for determination of the enzyme activity. → First evaluation of K m for the enzyme. → The effects of cadmium (II) not only on the activity of the enzyme but also on K m . -- Abstract: The synthesis of phytochelatins is catalyzed by γ-Glu-Cys dipeptidyl transpeptidase called phytochelatin synthase (PCS). Aim of this study was to suggest a new tool for determination of phytochelatin synthase activity in the tobacco BY-2 cells treated with different concentrations of the Cd(II). After the optimization steps, an experiment on BY-2 cells exposed to different concentrations of Cd(NO 3 ) 2 for 3 days was performed. At the end of the experiment, cells were harvested and homogenized. Reduced glutathione and cadmium (II) ions were added to the cell suspension supernatant. These mixtures were incubated at 35 o C for 30 min and analysed using high performance liquid chromatography coupled with electrochemical detector (HPLC-ED). The results revealed that PCS activity rises markedly with increasing concentration of cadmium (II) ions. The lowest concentration of the toxic metal ions caused almost three fold increase in PCS activity as compared to control samples. The activity of PCS (270 fkat) in treated cells was more than seven times higher in comparison to control ones. K m for PCS was estimated as 2.3 mM.

Controlling the release of active compounds from the inorganic carrier halloysite

Energy Technology Data Exchange (ETDEWEB)

Tescione, F.; Buonocore, G. G.; Stanzione, M.; Oliviero, M.; Lavorgna, M. [National Research Council - Institute of Composites and Biomedical Materials, P.le E. Fermi, 1 80055 Portici (Naples) (Italy)

2014-05-15

Halloysite (HNTs), a natural material characterized by a nanotube structure, has been used as an inorganic carrier of active compounds in several applications from medicine to anticorrosion coatings. In this present work, vanillin (VAN) used as a antimicrobial model, has been encapsulated within HNTs for exploiting its applicability in the active food packaging sector. The molecule release rate has been controlled by crosslinking at the tube ends the loaded vanillin with copper ions, thus producing a stopper network. The vanillin-loaded HNTs were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis. The antimicrobial release kinetics from the loaded nanoparticles (VAN/HNTs) in water was investigated using UV-vis spectroscopy. The results show that the vanillin crosslinked with cupper ions is a feasible method to tailor the release rate of antimicrobial model from HTNs nanoparticles.

Controlling the release of active compounds from the inorganic carrier halloysite

International Nuclear Information System (INIS)

Tescione, F.; Buonocore, G. G.; Stanzione, M.; Oliviero, M.; Lavorgna, M.

2014-01-01

Halloysite (HNTs), a natural material characterized by a nanotube structure, has been used as an inorganic carrier of active compounds in several applications from medicine to anticorrosion coatings. In this present work, vanillin (VAN) used as a antimicrobial model, has been encapsulated within HNTs for exploiting its applicability in the active food packaging sector. The molecule release rate has been controlled by crosslinking at the tube ends the loaded vanillin with copper ions, thus producing a stopper network. The vanillin-loaded HNTs were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis. The antimicrobial release kinetics from the loaded nanoparticles (VAN/HNTs) in water was investigated using UV-vis spectroscopy. The results show that the vanillin crosslinked with cupper ions is a feasible method to tailor the release rate of antimicrobial model from HTNs nanoparticles

Effects of electrokinetic treatment of a heavy metal contaminated soil on soil enzyme activities

International Nuclear Information System (INIS)

Cang Long; Zhou Dongmei; Wang Quanying; Wu Danya

2009-01-01

There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment to affect soil enzyme activities were explored. After treatments with 1-3 V cm -1 of voltage gradient for 420 h, soil pH, electrical conductivity (EC), soil organic carbon, dissolved organic carbon (DOC), soil heavy metal concentration and enzyme activities were analyzed. The results showed that the average removal efficiencies of soil copper were about 65% and 83% without and with pH control of catholyte, respectively, and all the removal efficiencies of cadmium were above 90%. The soil invertase and catalase activities increased and the highest invertase activity was as 170 times as the initial one. The activities of soil urease and acidic phosphatase were lower than the initial ones. Bivariate correlation analyses indicated that the soil invertase and acidic phosphatase activities were significantly correlated with soil pH, EC, and DOC at P < 0.05, but the soil urease activities had no correlation with the soil properties. On the other hand, the effects of DC electric current on solution invertase and catalase enzyme protein activities indicated that it had negative effect on solution catalase activity and little effect on solution invertase activity. From the change of invertase and catalase activities in soil and solution, the conclusion can be drawn that the dominant effect mechanism is the change of soil properties by EK treatments.

Effects of electrokinetic treatment of a heavy metal contaminated soil on soil enzyme activities

Energy Technology Data Exchange (ETDEWEB)

Cang Long [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhou Dongmei, E-mail: dmzhou@issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Wang Quanying; Wu Danya [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China)

2009-12-30

There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment to affect soil enzyme activities were explored. After treatments with 1-3 V cm{sup -1} of voltage gradient for 420 h, soil pH, electrical conductivity (EC), soil organic carbon, dissolved organic carbon (DOC), soil heavy metal concentration and enzyme activities were analyzed. The results showed that the average removal efficiencies of soil copper were about 65% and 83% without and with pH control of catholyte, respectively, and all the removal efficiencies of cadmium were above 90%. The soil invertase and catalase activities increased and the highest invertase activity was as 170 times as the initial one. The activities of soil urease and acidic phosphatase were lower than the initial ones. Bivariate correlation analyses indicated that the soil invertase and acidic phosphatase activities were significantly correlated with soil pH, EC, and DOC at P < 0.05, but the soil urease activities had no correlation with the soil properties. On the other hand, the effects of DC electric current on solution invertase and catalase enzyme protein activities indicated that it had negative effect on solution catalase activity and little effect on solution invertase activity. From the change of invertase and catalase activities in soil and solution, the conclusion can be drawn that the dominant effect mechanism is the change of soil properties by EK treatments.

Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

OpenAIRE

Ivan Stojanović; Vinko Šimunović; Vesna Alar; Frankica Kapor

2018-01-01

Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC) content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispens...

Activation of human leukocytes on tantalum trabecular metal in comparison to commonly used orthopedic metal implant materials.

Science.gov (United States)

Schildhauer, T A; Peter, E; Muhr, G; Köller, M

2009-02-01

We analyzed leukocyte functions and cytokine response of human leukocytes toward porous tantalum foam biomaterial (Trabecular Metaltrade mark, TM) in comparison to equally sized solid orthopedic metal implant materials (pure titanium, titanium alloy, stainless steel, pure tantalum, and tantalum coated stainless steel). Isolated peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophil leukocytes (PMN) were cocultured with equally sized metallic test discs for 24 h. Supernatants were analyzed for cytokine content by enzyme-linked immunosorbent assay. Compared to the other used test materials there was a significant increase in the release of IL (interleukin)-1ra and IL-8 from PMN, and of IL-1ra, IL-6, and TNF-alpha from PBMC in response to the TM material. The cytokine release correlated with surface roughness of the materials. In contrast, the release of IL-2 was not induced showing that mainly myeloid leukocytes were activated. In addition, supernatants of these leukocyte/material interaction (conditioned media, CM) were subjected to whole blood cell function assays (phagocytosis, chemotaxis, bacterial killing). There was a significant increase in the phagocytotic capacity of leukocytes in the presence of TM-conditioned media. The chemotactic response of leukocytes toward TM-conditioned media was significantly higher compared to CM obtained from other test materials. Furthermore, the bactericidal capacity of whole blood was enhanced in the presence of TM-conditioned media. These results indicate that leukocyte activation at the surface of TM material induces a microenvironment, which may enhance local host defense mechanisms.

Selective metal binding to Cys-78 within endonuclease V causes an inhibition of catalytic activities without altering nontarget and target DNA binding

International Nuclear Information System (INIS)

Prince, M.A.; Friedman, B.; Gruskin, E.A.; Schrock, R.D. III; Lloyd, R.S.

1991-01-01

T4 endonuclease V is a pyrimidine dimer-specific DNA repair enzyme which has been previously shown not to require metal ions for either of its two catalytic activities or its DNA binding function. However, we have investigated whether the single cysteine within the enzyme was able to bind metal salts and influence the various activities of this repair enzyme. A series of metals (Hg2+, Ag+, Cu+) were shown to inactivate both endonuclease Vs pyrimidine dimer-specific DNA glycosylase activity and the subsequent apurinic nicking activity. The binding of metal to endonuclease V did not interfere with nontarget DNA scanning or pyrimidine dimer-specific binding. The Cys-78 codon within the endonuclease V gene was changed by oligonucleotide site-directed mutagenesis to Thr-78 and Ser-78 in order to determine whether the native cysteine was directly involved in the enzyme's DNA catalytic activities and whether the cysteine was primarily responsible for the metal binding. The mutant enzymes were able to confer enhanced ultraviolet light (UV) resistance to DNA repair-deficient Escherichia coli at levels equal to that conferred by the wild type enzyme. The C78T mutant enzyme was purified to homogeneity and shown to be catalytically active on pyrimidine dimer-containing DNA. The catalytic activities of the C78T mutant enzyme were demonstrated to be unaffected by the addition of Hg2+ or Ag+ at concentrations 1000-fold greater than that required to inhibit the wild type enzyme. These data suggest that the cysteine is not required for enzyme activity but that the binding of certain metals to that amino acid block DNA incision by either preventing a conformational change in the enzyme after it has bound to a pyrimidine dimer or sterically interfering with the active site residue's accessibility to the pyrimidine dimer

Visible light active TiO{sub 2} films prepared by electron beam deposition of noble metals

Energy Technology Data Exchange (ETDEWEB)

Hou Xinggang, E-mail: hou226@163.co [Department of Physics, Tianjin Normal University, Tianjin 300387 (China); Ma Jun [Department of Physics, Tianjin Normal University, Tianjin 300387 (China); Liu Andong [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Li Dejun; Huang Meidong; Deng Xiangyun [Department of Physics, Tianjin Normal University, Tianjin 300387 (China)

2010-03-15

TiO{sub 2} films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO{sub 2} films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO{sub 2} is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO{sub 2} films by this method is affected by the concentration of impregnating solution.

Study of heavy metals in the grass-milk product chain by means of neutron activation and atomic absorption

Energy Technology Data Exchange (ETDEWEB)

Bruant, C; Bruant, J P; Neuburger, M; Vassal, L; Disant, C; Bittel, R; Fourcy, A

1974-12-31

with the heavy metals Hg, Cu, Zn, Pb, and Cd is studied. The first three metals were determined by neutron activation and tae last two by atomic absorption spectrophotometry. The chemical rature of these metals and their biological effect leads to different results from those obtained for tae principal fission products. As a rule the heavy metal concentrations at harvest are much lower than taat of the foods ingested by lactating cows. The cow plays the role of filter. If the concentration of these elements is considered in mu g/g of fresh material there is a reconcentration of these heavy metals in cream and cheese, probably cornected with their physico-chemical affinity for proteins. (JSR)

Universal dependence of hydrogen oxidation and evolution reaction activity of platinum-group metals on pH and hydrogen binding energy.

Science.gov (United States)

Zheng, Jie; Sheng, Wenchao; Zhuang, Zhongbin; Xu, Bingjun; Yan, Yushan

2016-03-01

Understanding how pH affects the activity of hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is key to developing active, stable, and affordable HOR/HER catalysts for hydroxide exchange membrane fuel cells and electrolyzers. A common linear correlation between hydrogen binding energy (HBE) and pH is observed for four supported platinum-group metal catalysts (Pt/C, Ir/C, Pd/C, and Rh/C) over a broad pH range (0 to 13), suggesting that the pH dependence of HBE is metal-independent. A universal correlation between exchange current density and HBE is also observed on the four metals, indicating that they may share the same elementary steps and rate-determining steps and that the HBE is the dominant descriptor for HOR/HER activities. The onset potential of CO stripping on the four metals decreases with pH, indicating a stronger OH adsorption, which provides evidence against the promoting effect of adsorbed OH on HOR/HER.

Activation analysis of dual-purpose metal cask after the end of design lifetime for decommission

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Man; Ku, Ji Young; Dho Ho Seog; Cho, Chun Hyung [Korea Radioactive Waste Agency, Daejeon (Korea, Republic of); Ko, Jae Hun [Korea Nuclear Engineering and Service Co., Daejeon (Korea, Republic of)

2016-12-15

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5·ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, {sup 60}Co had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as {sup 28}Al and {sup 24}Na had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that

Activities and Issues in Monitoring Scrap Metal Against Radioactive Sources

Energy Technology Data Exchange (ETDEWEB)

Chen, S.Y., E-mail: sychen@anl.gov [Argonne National Laboratory, Argonne, IL (United States)

2011-07-15

Over the past few decades, the global scrap metal industry has grown increasingly vigilant regarding radioactive contamination. Accidental melts of radioactive sources in some smelting facilities, in particular, have caused considerable damage and required recovery efforts costing tens of millions of dollars. In response, the industry has developed and deployed countermeasures. Increasingly expensive and sophisticated radiation monitoring devices have been implemented at key scrap entry points - ports and scrapyards. Recognition of the importance of such endeavors has led to a series of activities aimed at establishing organized and coordinated efforts among the interested parties. Recent concerns over the potential use of radioactive sources for radiological devices in terrorist acts have substantially heightened the need for national and international authorities to further control, intercept, and secure the sources that have escaped the regulatory domain. Enhanced collaboration by the government and industry could substantially improve the effectiveness of efforts at control; the 'Spanish Protocol' as developed by the Spanish metal industry and government regulators is a good example of such collaboration. (author)

Development of active CFRP/metal laminates and their demonstrations in complicated forms

Science.gov (United States)

Asanuma, H.; Nakata, T.; Tanaka, T.; Imori, M.; Haga, O.

2006-03-01

This paper describes development of high performance CFRP/metal active laminates and demonstrations of them in complicated forms. Various types of the laminates were made by hot-pressing of an aluminum, aluminum alloys, a stainless steel and a titanium for the metal layer as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material, a unidirectional KFRP prepreg as a low CTE/insulating material. The aluminum and its alloy type laminates have almost the same and the highest room temperature curvatures and they linearly change with increasing temperature up to their fabrication temperature. The curvature of the stainless steel type jumps from one to another around its fabrication temperature, whereas the titanium type causes a double curvature and its change becomes complicated. The output force of the stainless steel type attains the highest of the three under the same thickness. The aluminum type successfully increased its output force by increasing its thickness and using its alloys. The electric resistance of the CFRP layer can be used to monitor the temperature, that is, the curvature of the active laminate because the curvature is a function of temperature. The aluminum type active laminate was made into complicated forms, that is, a hatch, a stack, a coil and a lift types, and their actuation performances were successfully demonstrated.

Antimicrobial activity of transition metal acid MoO3 prevents microbial growth on material surfaces

International Nuclear Information System (INIS)

Zollfrank, Cordt; Gutbrod, Kai; Wechsler, Peter; Guggenbichler, Josef Peter

2012-01-01

Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H 2 MoO 4 ), which is based on molybdenum trioxide (MoO 3 ). The modification of various materials (e.g. polymers, metals) with MoO 3 particles or sol–gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments. Highlights: ► The presented modifications of materials surfaces with MoO 3 are non-cytotoxic and decrease biofilm growth and bacteria transmission. ► The material is insensitive towards emerging resistances of bacteria. ► Strong potential to reduce spreading of infectious agents on inanimate surfaces.

New insight into adsorption characteristics and mechanisms of the biosorbent from waste activated sludge for heavy metals.

Science.gov (United States)

Zhou, Yun; Zhang, Zhiqiang; Zhang, Jiao; Xia, Siqing

2016-07-01

The adsorption characteristics and mechanisms of the biosorbent from waste activated sludge were investigated by adsorbing Pb(2+) and Zn(2+) in aqueous single-metal solutions. A pH value of the metal solutions at 6.0 was beneficial to the high adsorption quantity of the biosorbent. The optimal mass ratio of the biosorbent to metal ions was found to be 2. A higher adsorption quantity of the biosorbent was achieved by keeping the reaction temperature below 55°C. Response surface methodology was applied to optimize the biosorption processes, and the developed mathematical equations showed high determination coefficients (above 0.99 for both metal ions) and insignificant lack of fit (p=0.0838 and 0.0782 for Pb(2+) and Zn(2+), respectively). Atomic force microscopy analyses suggested that the metal elements were adsorbed onto the biosorbent surface via electrostatic interaction. X-ray photoelectron spectroscopy analyses indicated the presence of complexation (between -NH2, -CN and metal ions) and ion-exchange (between -COOH and metal ions). The adsorption mechanisms could be the combined action of electrostatic interaction, complexation and ion-exchange between functional groups and metal ions. Copyright © 2016. Published by Elsevier B.V.

Methodologies for hydrogen determination in metal oxides by prompt gamma activation analysis

International Nuclear Information System (INIS)

Alvarez, E.; Biegalski, S.R.; Landsberger, S.

2007-01-01

Prompt gamma activation analysis (PGAA), available at University of Texas at Austin (UT), has been employed for the direct determination of hydrogen content in a series of metal oxide materials typically used as cathodes in lithium ion battery systems. Special attention was given to the experimental setup including potential sources of error and system calibration for the detection of hydrogen. Spectral interference with hydrogen arising from cobalt was identified and corrected for. Limits of detection as a function of cobalt mass present in a given sample are also discussed. PGAA has proven to be a novel and precise technique for the determination of hydrogen in metal oxides. This type of investigation could provide valuable insight regarding the factors that limit the practical capacities of lithium ion oxide cathodes

ANTIBACTERIAL ACTIVITY OF BENZIMIDAZOLES 2-THIO, 2-AMINODERIVATIVES AND COMPLEXES OF BENZIMIDAZOLES WITH TRANSITIONAL METALS

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E. I. Mayboroda

2014-01-01

Full Text Available The literature data about antibacterial properties of benzimidazole 2-thio-, 2-aminoderivatives and benzimidazole complexes have been generalized and systematized in the review. Today prevention and treatment of diseases caused by microorganisms is an actual problem of modern therapy. Therefore, the search for active molecules, the based on them development of some new, more effective antimicrobial agents is an important task of modern pharmaceutical chemistry. Promising compounds for solving these problems are benzimidazole derivatives. They are available, functionally capable, stable and have a wide spectrum of biological activities (antiviral, anthelmintic, antibacterial, anticancer, antidiabetic.The purpose of this paper is to generalize and systematize information about the antimicrobial action of 2-thio-, 2-amino-substituted benzimidazoles and benzimidazole derivatives complexes with transition metals.These compounds and their complexes with transition metals are active against pathogenic strains Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhimurium, Proteus vulgaris, Bacillus cereus, Micrococcus luteus, Helicobacter рylori and others.

Influences of species of metals and supports on the hydrogenation activity of carbon-supported metal sulfides catalysts; Tanso biryushi tanji shokubai no suisoka kassei ni taisuru kassei kinzoku oyobi tantaishu no eikyo

Energy Technology Data Exchange (ETDEWEB)

Sakanishi, K.; Hasuo, H.; Taniguchi, H.; Nagamatsu, T.; Mochida, I. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

1996-10-28

In order to design catalysts suitable for primary liquefaction stage and secondary upgrading stage respectively in the multi-stage liquefaction process, various carbon-supported catalysts were prepared. Catalytic activities of them were investigated for the hydrogenation of 1-methylnaphthalene, to discuss the influences of metals and carbon species on the catalytic activity. Various water soluble and oil soluble Mo and Ni salts were used for NiMo supported catalysts. Among various carbon supports, Ketjen Black (KB) was effective for preparing the catalyst showing the most excellent hydrogenation activity. The KB and Black Pearl 2000 (BP2000) showing high hydrogenation activity were fine particles having high specific surface area more than 1000 m{sup 2}/g and primary particle diameter around 30 nm. This was inferred to contribute to the high dispersion support of active metals. Since such fine particles of carbon exhibited hydrophobic surface, they were suitable for preparing catalysts from the methanol-soluble metals. Although Ni and Mo added iron-based catalysts provided lower aromatic hydrogenation activity, they exhibited liquefaction activity competing with the NiMo/KB catalyst. 3 refs., 1 fig., 3 tabs.

Seasonal changes in antioxidant enzyme activities of freshwater biofilms in a metal polluted Mediterranean stream.

Science.gov (United States)

Bonet, Berta; Corcoll, Natàlia; Acuňa, Vicenç; Sigg, Laura; Behra, Renata; Guasch, Helena

2013-02-01

While seasonal variations in fluvial communities have been extensively investigated, effects of seasonality on community responses to environmental and/or chemical stress are poorly documented. The aim of this study was to describe antioxidant enzyme activity (AEA) variability in fluvial biofilms over an annual cycle, under multi-stress scenarios due to environmental variability (e.g., light intensity, water flow, and temperature) and metal pollution (Zn, Mn and Fe). The annual monitoring study was performed at three sites according to their water and biofilm metal concentrations. Metal concentration was affected by water flow due to dilution. Low flow led to higher dissolved Zn concentrations, and thus to higher Zn accumulation in the biofilm. Water temperature, light intensity and phosphate concentration were the environmental factors which determined the seasonality of biofilm responses, whereas dissolved Zn and Zn accumulation in biofilms were the parameters linked to sites and periods of highest metal pollution. Community algal succession, from diatoms in cold conditions to green algae in warm conditions, was clearer in the non metal-polluted site than in those metal-polluted, presumably due to the selection pressure exerted by metals. Most AEA were related with seasonal environmental variability at the sites with low or no-metal pollution, except glutathione-S-transferase (GST) which was related with Zn (dissolved and accumulated in biofilm) pollution occurring at the most polluted site. We can conclude that seasonal variations of community composition and function are masked by metal pollution. From this study we suggest the use of a multi-biomarker approach, including AEA and a set of biological and physicochemical parameters as an effect-based field tool to assess metal pollution. Copyright © 2012 Elsevier B.V. All rights reserved.

Determination of phosphorus in metals by neutron activation and chemical separation as hydride

International Nuclear Information System (INIS)

Rouchaud, J.C.; Fedoroff, M.

1993-01-01

Phosphorous at trace levels alters the properties of metals and alloys. Its determination was investigated by radiochemical neutron activation analysis. Separation by solvent extraction or by evolution as P 0 showed to be neither selective nor quantitative in presence of a metallic matrix. Therefore, a new method of separation by reduction to phosphorous hydride followed by liquid scintillation counting was investigated. This method is quantitative in the case of non-radioactive iron doped with radioactive phosphorus. At present, the separation is not quantitative for irradiation iron samples, owing probably to hot atom or radiation effects. A detection limit of 0.002 μg is expected. (author) 10 refs.; 1 fig.; 3 tabs

Chemical activation of molecules by metals: Experimental studies of electron distributions and bonding

International Nuclear Information System (INIS)

Lichienberger, D.L.

1990-10-01

This quarter has witnessed further progress both in our experimental methods of photoelectron spectroscopy and in our understanding the fundamental relationships between ionization energies and the chemistry of transition metal species. Progress continues on the new gas phase photoelectron spectrometer that combine improved capabilities for HeI/HeII UPS, XPS, and Auger investigations of organometallic molecules. Several measurements have been accomplished this year that were not possible previously. We have published the formal relationship between measured molecular ionization energies and thermodynamic bond dissociation energies, and applied the relationships to homonuclear and heteronuclear diatomic molecules, multiple bonds, and metal-ligand bonds. Studies of C-H bond activation have continued with examination of different degrees of Si-H bond addition to metals. the electronic effects of intermolecular interactions have been observed by comparing the ionizations of metal complexes in the gas phase with the ionizations of monolayer solid organometallic films prepared in ultra-high vacuum. The orientations of the molecules have been determined by scanning tunneling microscopy. Especially interesting has been the recent application of these techniques to the characterization of the soccer-ball shaped C 60 molecule, buckminsterfullerene. Studies of the following complexes are described : Fe, Os, Nb, Mo, Rh, Re, Al, and Mn. 19 refs

Comparison of the toxicity of some metals and their tetracyanide complexes on the respiration of non acclimated activated sludges.

Science.gov (United States)

Morozzi, G; Cenci, G

1978-12-01

The toxic effect of the metal ions of cadmium, zinc, nickel and mercury and their tetracyanide salt complexes, on the activated sludge not previously acclimated, has been studied. The evaluation of the effect was carried out using both the Warburg and TTC-method. The results obtained have shown that the toxicity of the cadmium and zinc complexes is higher than that of the corresponding metals, while the toxicity of Ni(CN)4(2-) is lower than that of the corresponding metals. No differences have been found between the effect of mercury and the corresponding tetracyanide complex. From the data obtained it appears that it is not possible to generalize about the biological effect of complexation with the CN- group, but it should be stated that, generally, there are substantial differences between metals and their cyanide complexes as far as toxicity for activated sludge is concerned.

Metal halides vapor lasers with inner reactor and small active volume.

Science.gov (United States)

Shiyanov, D. V.; Sukhanov, V. B.; Evtushenko, G. S.

2018-04-01

Investigation of the energy characteristics of copper, manganese, lead halide vapor lasers with inner reactor and small active volume 90 cm3 was made. The optimal operating pulse repetition rates, temperatures, and buffer gas pressure for gas discharge tubes with internal and external electrodes are determined. Under identical pump conditions, such systems are not inferior in their characteristics to standard metal halide vapor lasers. It is shown that the use of a zeolite halogen generator provides lifetime laser operation.

Flower-Like CuO/ZnO Hybrid Hierarchical Nanostructures Grown on Copper Substrate: Glycothermal Synthesis, Characterization, Hydrophobic and Anticorrosion Properties.

Science.gov (United States)

Beshkar, Farshad; Khojasteh, Hossein; Salavati-Niasari, Masoud

2017-06-25

In this work we have demonstrated a facile formation of CuO nanostructures on copper substrates by the oxidation of copper foil in ethylene glycol (EG) at 80 °C. On immersing a prepared CuO film into a solution containing 0.1 g Zn(acac)₂ in 20 mL EG for 8 h, ZnO flower-like microstructures composed of hierarchical three-dimensional (3D) aggregated nanoparticles and spherical architectures were spontaneously formed at 100 °C. The as-synthesized thin films and 3D microstructures were characterized using XRD, SEM, and EDS techniques. The effects of sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB), and polyethylene glycol (PEG) 6000 as surfactants and stabilizers on the morphology of the CuO and ZnO structures were discussed. Possible growth mechanisms for the controlled organization of primary building units into CuO nanostructures and 3D flower-like ZnO architectures were proposed. The hydrophobic property of the products was characterized by means of water contact angle measurement. After simple surface modification with stearic acid and PDMS, the resulting films showed hydrophobic and even superhydrophobic characteristics due to their special surface energy and nano-microstructure morphology. Importantly, stable superhydrophobicity with a contact angle of 153.5° was successfully observed for CuO-ZnO microflowers after modification with PDMS. The electrochemical impedance measurements proved that the anticorrosion efficiency for the CuO/ZnO/PDMS sample was about 99%.

Flower-Like CuO/ZnO Hybrid Hierarchical Nanostructures Grown on Copper Substrate: Glycothermal Synthesis, Characterization, Hydrophobic and Anticorrosion Properties

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Farshad Beshkar

2017-06-01

Full Text Available In this work we have demonstrated a facile formation of CuO nanostructures on copper substrates by the oxidation of copper foil in ethylene glycol (EG at 80 °C. On immersing a prepared CuO film into a solution containing 0.1 g Zn(acac2 in 20 mL EG for 8 h, ZnO flower-like microstructures composed of hierarchical three-dimensional (3D aggregated nanoparticles and spherical architectures were spontaneously formed at 100 °C. The as-synthesized thin films and 3D microstructures were characterized using XRD, SEM, and EDS techniques. The effects of sodium dodecyl sulphate (SDS, cetyltrimethylammonium bromide (CTAB, and polyethylene glycol (PEG 6000 as surfactants and stabilizers on the morphology of the CuO and ZnO structures were discussed. Possible growth mechanisms for the controlled organization of primary building units into CuO nanostructures and 3D flower-like ZnO architectures were proposed. The hydrophobic property of the products was characterized by means of water contact angle measurement. After simple surface modification with stearic acid and PDMS, the resulting films showed hydrophobic and even superhydrophobic characteristics due to their special surface energy and nano-microstructure morphology. Importantly, stable superhydrophobicity with a contact angle of 153.5° was successfully observed for CuO-ZnO microflowers after modification with PDMS. The electrochemical impedance measurements proved that the anticorrosion efficiency for the CuO/ZnO/PDMS sample was about 99%.

Determination of noble metals in geological materials by radiochemical neutron-activation analysis

International Nuclear Information System (INIS)

Ahmad, I.; Ahmad, S.; Morris, D.F.C.

1977-01-01

A method for the determination of platinum, palladium, gold and iridium in geological materials following activation with thermal neutrons is described. Radionuclides formed from the elements are separated by a scheme based largely on liquid-liquid extractions. The procedure has been applied to the analysis of US Geological Survey standard rocks and to studies of the distribution of the noble metals in lateritic nickel ores. (author)

Study of trace metals in phosphorite by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Delgado, J.U.

1984-01-01

Methods to determine U, Th and other constituent elements in mineral matrices by the instrumental neutron activation analysis (INAA) have been widely developed. The precise knowledge of these constituent elements is very important for the nuclear technology development. This justifies the use of a technique capable to extract information from small samples. The present work aimed the study of the phosphorites deriving from the State of Pernambuco (PE, Brazil). Its uranium concentration corresponds to one of the highest values found in industrial exploration of phosphate rocks. An experimental methodology based on the INAA associated to the cluster technique was developed. Concentrations of 22 different elements present in the ore were determined with less than 10% uncertainty. The results have shown high correlations in behavior between uranium and rare earth metals. However, the inverse was noted in relation to transition metals. These results indicate the applicability of this method to determine concentrations as well as to classify correlated element groups in mineral matrices. (Author) [pt

Synthesis, spectral characterisation, morphology, biological activity and DNA cleavage studies of metal complexes with chromone Schiff base

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P. Kavitha

2016-07-01

Full Text Available Cu(II, Co(II, Ni(II and Zn(II complexes have been synthesized using 3-((pyridine-2-yliminomethyl-4H-chromen-4-one as a ligand derived from 3-formyl chromone and 2-amino pyridine. All the complexes were characterised by analytical, conductivity, IR, electronic, magnetic, ESR, thermal, powder XRD and SEM studies. The analytical data revealed that the metal to ligand molar ratio is 1:2 in all the complexes. Molar conductivity data indicates that all the complexes are neutral in nature. On the basis of magnetic and electronic spectral data, octahedral geometry is proposed for all the complexes. Thermal behaviour of the synthesized complexes indicates the coordinated and lattice water molecules are present in the complexes. The X-ray diffraction data suggest a triclinic system for all compounds. Different surface morphologies were identified from SEM micrographs. All metal complexes exhibit fluorescence. The antimicrobial and nematicidal activity data show that metal complexes are more potent than the parent ligand. The DNA cleavage activity of the ligand and its metal complexes were observed in the presence of H2O2.

Screening of catalytic oxygen reduction reaction activity of metal-doped graphene by density functional theory

International Nuclear Information System (INIS)

Chen, Xin; Chen, Shuangjing; Wang, Jinyu

2016-01-01

Highlights: • The screened M-G structures are very thermodynamically stable, and the stability is even higher than that of the corresponding bulk metal surfaces. • The binding energies of ORR intermediates suggest that they are not linear dependence, which are different form the cases found on some metal-based catalysts. • The Au-, Co-, and Ag-G structures could be used as the ORR catalysts. - Abstract: Graphene doping is a promising direction for developing effective oxygen reduction reaction (ORR) catalysts. In this paper, we computationally investigated the ORR performance of 10 kinds of metal-doped graphene (M-G) catalysts, namely, Al-, Si-, Mn-, Fe-, Co-, Ni-, Pd-, Ag-, Pt-, and Au-G. The results shown that the binding energies of the metal atoms incorporated into the graphene vacancy are higher than their bulk cohesive energies, indicating the formed M-G catalysts are even more stable than the corresponding bulk metal surfaces, and thus avoid the metals dissolution in the reaction environment. We demonstrated that the linear relation among the binding energies of the ORR intermediates that found on metal-based materials does not hold for the M-G catalysts, therefore a single binding energy of intermediate alone is not sufficient to evaluate the ORR activity of an arbitrary catalyst. By analysis of the detailed ORR processes, we predicted that the Au-, Co-, and Ag-G materials can be used as the ORR catalysts.

Synthesis and Biological Activities on Metal Complexes of 2,5-Diamino-1,3,4-thiadiazole Derived from Semicarbazide Hydrochloride

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Matthew A. Adebayo

2011-07-01

Full Text Available A bioactive ligand, 2,5-diamino-1,3,4-thiadiazole (L, derived from semicarbazide hydrochloride, and its metal complexes were prepared and characterized. The complexes were characterized using elemental, infra-red, ultraviolet/visible, magnetic moment, atomic absorption, thin layer chromatography and molar conductance measurements. The IR data revealed that the ligand (L behaved as a tridentate neutral ligand. It coordinated to the metal ion via sulphur and nitrogen of the amines. The molar conductance data reveal that the chelates are non-electrolytes. From the Ultraviolet/Visible spectra and magnetic moment data, the complexes were found to have octahedral geometrical structure. In vivo evaluation of the antimicrobial activities of the metal complexes and the ligands showed greater activity against some micro-organisms when compared to the parent compounds. The chelates do not show toxicity against the activities of enzymes from homogenates of liver, kidney and serum in experimental rats.

Influence of Ferrocene and Transition Metals on the Biological Activities of Schiff Bases

International Nuclear Information System (INIS)

Sadeq, A.; Fatesh, S.A.; Ibrahim, A.A.

2016-01-01

A series of organic and organometallic Schiff bases bearing phenylferrocene and their six transition metal complexes have been prepared and tested for their potential biological applications by using antifungal, antibacterial, antitumor activities, toxicity testing against the brine shrimp and DNA damage analysis. The copper and cobalt complexes of organic Schiff base showed significant antibacterial activity. The antifungal activities tested against six fungal strains revealed that N-(4-hydroxybenzylidene) aniline (A5) had the highest antifungal activity. Most of these compounds showed cytotoxic activity against the brine shrimp. The results of showed that these compounds had significant antitumor activity, up to 97% in the case of N-(4-chlorobenzylidene) aniline (A3). Only two compounds N-(2-hydroxy benzylidene) 4-ferrocenylaniline (F2) and Nickel (II) complex of organic Schiff base (CO/sub 2/) had DNA damaging activity at 20mg/ml concentration. (author)

Synthesis, characterization and biological profile of metal and azo-metal complexes of embelin

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R. Aravindhan

2014-12-01

Full Text Available The present study emphasizes synthesis and bioprofiling of embelin, embelin-metal (EM and embelin-azo-metal (EAM complexes in detail. EM complexes were prepared using pure embelin and d-block transition elements, namely Mn, Fe, Co, Ni, Cu, and Zn. Similarly, EAM complexes were synthesized using phenyl azo-embelin with the said transition metals. Embelin, EM, and EAM complexes were subjected to ultra violet visible spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance, electrospray ionization mass spectrometry, thermogravimetric analysis, carbon hydrogen nitrogen sulfur analysis. With regard to bioprofiling, the test complexes were studied for the antioxidant and antimicrobial activities. Results revealed that the prepared EM and EAM complexes form octahedral complexes with embelin with the yield in the range of 45–75%. All the instrumental analyses authenticate the interaction of metals with bidentate embelin through its enolic and quinonic oxygen atoms as [M(Emb2(H2O2]H2O and [M(Emb-Azo2(H2O2]. The antioxidant profile studies suggested that upon complexation with metals, the free radical scavenging activity of embelin reduced significantly. But, with regard to antimicrobial activity, cobalt and nickel embelin complexes displayed>80% growth inhibition in comparison with embelin alone. The hemolytic activity studies suggested that both embelin and the metal complexes are non-hemolytic. The reason for the reduction in antioxidant and an increase in antimicrobial activities were discussed in detail.

Evaluation of heavy metal uptake in micropterus salmoides (Largemouth Bass) of Lake Austin, TX by neutron activation analysis

International Nuclear Information System (INIS)

Weaver, J.; Wilson, W.H.; Biegalski, S.R.F.; O'Kelly, D.J.

2009-01-01

Neutron activation analysis was used to investigate and quantify the level of heavy metal uptake in the marine environment of Lake Austin in Austin, TX. Specifically, the samples studied were largemouth bass, or micropterus salmoides. The presence of heavy metals in the food chain presents multiple hazards, mostly as a food hazard for those species that ingest the fish, namely humans. To measure the concentrations of heavy metals in various fish samples, the nuclear analytical technique of neutron activation analysis (NAA) was used. Both epithermal and thermal irradiations were conducted for the NAA to look for short and long-lived radioisotopes, respectively. The samples themselves consisted of liver and tissue samples for each of the fish caught. Each sample was freeze-dried and homogenized before irradiation and spectrum acquisition. The results showed that all levels of heavy metals were not sufficient enough to make the fish unsafe for eating, with the highest levels being found for iron and zinc. Gold was found to be at much higher concentrations in the younger fish and virtually non-existent in the larger of the samples. (author)

Hydrogen–argon plasma pre-treatment for improving the anti-corrosion properties of thin Al2O3 films deposited using atomic layer deposition on steel

International Nuclear Information System (INIS)

Härkönen, Emma; Potts, Stephen E.; Kessels, Wilhelmus M.M.; Díaz, Belén; Seyeux, Antoine; Światowska, Jolanta; Maurice, Vincent; Marcus, Philippe; Radnóczi, György; Tóth, Lajos; Kariniemi, Maarit; Niinistö, Jaakko; Ritala, Mikko

2013-01-01

The effect of H 2 –Ar plasma pre-treatment prior to thermal atomic layer deposition (ALD) and plasma-enhanced atomic layer deposition (PEALD) of Al 2 O 3 films on steel for corrosion protection was investigated. Time-of-flight secondary ion mass spectrometry and transmission electron microscopy were used to observe the changes in the interface. The electrochemical properties of the samples were studied with polarization measurements, and the coating porosities were calculated from the polarization results for easier comparison of the coatings. Prior to thermal ALD the plasma pre-treatment was observed to reduce the amount of impurities at the interface and coating porosity by 1–3 orders of magnitude. The anti-corrosion properties of the PEALD coatings could also be improved by the pre-treatment. However, exposure of the pre-treatment plasma activated steel surface to oxygen plasma species in PEALD led to facile oxide layer formation in the interface. The oxide layer formed this way was thicker than the native oxide layer and appeared to be detrimental to the protective properties of the coating. The best performance for PEALD Al 2 O 3 coatings was achieved when, after the plasma pre-treatment, the surface was given time to regrow a thin protective interfacial oxide prior to exposure to the oxygen plasma. The different effects that thermal and plasma-enhanced ALD have on the substrate-coating interface were compared. The reactivity of the oxygen precursor was shown to have a significant influence on substrate surface in the early stages of film growth and thereafter also on the overall quality of the protective film. - Highlights: • Influence of H 2 –Ar plasma pre-treatment to ALD coatings on steel was studied. • The pre-treatment modified the coating–substrate interface composition and thickness. • The pre-treatment improved the barrier properties of the coatings

Neutron activation analysis of trace metals in the hair and organs of small animals treated chronically with Hg and Mn

International Nuclear Information System (INIS)

Ohmori, S.; Hashimoto, K.

1985-01-01

For the purpose of studying the secretion of exogenous toxic metals into hair, the relation between their concenrations in hair and in organs, and the metal shift Hg or Mn was orally administered to Guinea pigs for protracted periods. The distributions of metals in hair and organs were examined by means of neutron activation analysis. It was found that the administration of Hg at high dose resulted in abnormally high Hg levels in hair from the 2nd dosing week and in organs after 25 weeks of dosing, and in a reduced motor activity after 25 weeks of administration. There occurred metal shifts in hair as well. Administration of Mn at high doses, on the other hand, showed no such biological influences, although a dose-dependent increase of Mn in hair was detected with time. (author)

Cycloaddition of nitrones to metal-activated nitriles and isocyanides

International Nuclear Information System (INIS)

Bokach, Nadejda A

2010-01-01

1,3-Dipolar cycloaddition reactions of nitrones to nitriles and isocyanides are considered. Attention is focused on metal-mediated processes and the role played by the nature of the metal centre and its oxidation state. The published data on the selectivity of metal-mediated cycloaddition of nitrones to nitriles and the new data on the cycloaddition of nitrones to coordinated isocyanide ligands are summarized and analyzed.

Impact of Heavy Metals in Enzymatic Activity of Soils from Hidalgo, Mexico

International Nuclear Information System (INIS)

Reyes-Ortigoza, A. L.; Reyes-Solis, I. E.; Galicia-Palacios, M. S.; Montiel-Arteaga, S.

2009-01-01

The soils from Valle of Mezquital, Hidalgo, Mexico have been irrigated with waste waters from Mexico City for more than 88 years. the present investigation was made in order to know the relationship between heavy metal contents and time of irrigation with waste waters and production of CO 2 and enzymatic activity in soils from Valle Mezquital for knowing the disponibility of nutrients and degradation of soils. (Author)

Activity and functional diversity of microbial communities in long-term hydrocarbon and heavy metal contaminated soils

Directory of Open Access Journals (Sweden)

Markowicz Anna

2016-12-01

Full Text Available The impacts of long-term polycyclic aromatic hydrocarbons (PAHs and heavy metal pollution on soil microbial communities functioning were studied in soils taken from an old coke plant. The concentrations of PAHs in the tested soils ranged from 171 to 2137 mg kg-1. From the group of tested heavy metals, concentrations of lead were found to be the highest, ranging from 57 to 3478 mg kg-1, while zinc concentrations varied from 247 to 704 mg kg-1 and nickel from 10 to 666 mg kg-1. High dehydrogenase, acid and alkaline phosphatase activities were observed in the most contaminated soil. This may indicate bacterial adaptation to long-term heavy metal and hydrocarbon contamination. However, the Community Level Physiological Profiles (CLPPs analysis showed that the microbial functional diversity was reduced and influenced to a higher extent by some metals (Pb, Ni, moisture and conductivity than by PAHs.

The impact of seasonal varied human activity on characteristics and sources of heavy metals in metropolitan road dusts.

Science.gov (United States)

Men, Cong; Liu, Ruimin; Wang, Qingrui; Guo, Lijia; Shen, Zhenyao

2018-10-01

Due to significant human activity, road dust is becoming contaminated by heavy metals in many cities. To comprehensively investigate the variation of contamination level and sources of heavy metals in road dust, 10 heavy metals in road dust samples from Beijing, China, in both summer and winter, were evaluated by spatial analysis using geographic information system (GIS) mapping technology and the positive matrix factorization (PMF) Model. Although the concentrations of some heavy metals between summer and winter had similarities, the differences of others and spatial distributions of heavy metals between summer and winter were considerable. The mean concentrations of As, Cd, Cr, Cu, and Fe were lower in winter, while those of Hg, Mn, Ni, Pb, and Zn were higher. According to the values of the Pollution Index (PI) and Nemerow Integrated Pollution Index (NIPI), there were no obvious differences between summer and winter, but the range between different sites in winter was nearly twice that of summer. Based on the PMF model, four sources of heavy metals in the dust samples were identified. Although the types of sources were consistent, the relative contributions of each source differed between summer and winter. Non-exhaust vehicle emissions was the most important source in summer (34.47 wt%), while fuel combustion contributed the largest proportion to the total heavy metals in winter (32.40 wt%). The impact of each source also showed spatial variation different trends in summer and winter. With the alteration of seasons, intensity of human activities also changed, such as the number of tourists, energy needs for building temperature regulation, construction, and the amount of pesticides and fertilizer. That might be the reason for the variation of heavy metal concentrations and relative contribution of their sources between summer and winter. Copyright © 2018 Elsevier B.V. All rights reserved.

Augmenting granular activated carbon with natural clay for multicomponent sorption of heavy metals from aqueous solutions.

Science.gov (United States)

Mu'azu, Nuhu Dalhat; Essa, Mohammed Hussain; Lukman, Salihu

2017-10-01

Multicomponent adsorption of Cd, Cr, Cu, Pb and Zn onto date palm pits based granular activated carbon (GAC) augmented with highly active natural clay at different proportion was investigated. The effects of the initial pH and the adsorbents mixed ratio on the removal selectivity sequence of the metals evaluated. Batch adsorption experiments were undertaken at initial pH 2, 6 and 12. At initial pH 2, both the percent removal and the metals adsorptive capacity decreased with increasing GAC to clay ratio (from 0 to 1) with the percentage removal of Cd, Zn and Cr ions dropping from 68, 81, 100% to 43, 57 and 70%, respectively. At both pH 6 and 12, the percentage removals and adsorption capacities of all the heavy metal ions are higher than at pH 2. Selectivity sequences for pH 2, 6 and 12 followed the order Pb > Cr > Cu > Zn > Cd; Pb > Cr > Cu > Cd > Zn and Cd > Cr > Cu > Pb > Zn, respectively. The adsorption trends were analyzed in relation to point of zero charge and ξ-potential and the metals ions speciation at different pH. These results will help better understand the feasibility of augmenting GAC with natural clay minerals during fixed bed column test which is more beneficial for practical industrial applications.

Metal compounds in zeolites as active components of chemisorption and catalysis. Quantum chemical approach

International Nuclear Information System (INIS)

Zhidomirov, G.M.

1996-01-01

A short review of possible catalitic active sites associated with various types of metal species in zoolite is presented. The structural and electronic peculiarity of aluminum ions in zeolite lattice and their distribution in the lattice are discussed on the basis of quantum chemical calculations in connection with the formation of Broensted activity of zeolites. Various molecular models of Lewis Acid Sites associated the extra-lattice oxide-hydroxide aluminum species have been investigated by means of density functional model cluster calculations using CO molecule as a probe. Probable ways of formation of the selective oxidation center in FeZSM-5 by decomposition of dinitrogen monoxide have been studied by ab-initio quantum chemical calculations. The immediate oxidizing site is reasonably represented by the binuclear iron-hydroxide cluster with peroxo-like fragment located between iron atoms. Various probable intermediates of the selective oxidation center formation resulted from interaction of a hydroperoxide molecule with a lattice titanium ion in titanium silicalite have been investigated by quantum chemical calculations. It was concluded that this reaction requires essential structural reconstruction in the vicinity of the titanium ion. Probability of this structural reconstruction is discussed. Possible reasons of an electron-deficient and electron-enriched state of metal particles entrapped in zoolite cavities are discussed. Also, various probable molecular models of such modified metal particles in zeolite are considered

C-H functionalization: thoroughly tuning ligands at a metal ion, a chemist can greatly enhance catalyst's activity and selectivity.

Science.gov (United States)

Shul'pin, Georgiy B

2013-09-28

This brief essay consists of a few "exciting stories" devoted to relations within a metal-complex catalyst between a metal ion and a coordinated ligand. When, as in the case of a human couple, the rapport of the partners is cordial and a love cements these relations, a chemist finds an ideal married couple, in other words he obtains a catalyst of choice which allows him to functionalize C-H bonds very efficiently and selectively. Examples of such lucky marriages in the catalytic world of ions and ligands are discussed here. Activity of the catalyst is characterized by turnover number (TON) or turnover frequency (TOF) as well as by yield of a target product. Introducing a chelating N,N- or N,O-ligand to the catalyst molecule (this can be an iron or manganese derivative) sharply enhances its activity. However, the activity of vanadium derivatives (with additionally added to the solution pyrazinecarboxylic acid, PCA) as well as of various osmium complexes does not dramatically depend on the nature of ligands surrounding metal ions. Complexes of these metals are very efficient catalysts in oxidations with H2O2. Osmium derivatives are record-holders exhibiting extremely high TONs whereas vanadium complexes are on the second position. Finally, elegant examples of alkane functionalization on the ions of non-transition metals (aluminium, gallium etc.) are described when one ligand within the metal complex (namely, hydroperoxyl ligand HOO(-)) helps other ligand of this complex (H2O2 molecule coordinated to the metal) to disintegrate into two species, generating very reactive hydroxyl radical. Hydrogen peroxide molecule, even ligated to the metal ion, is perfectly stable without the assistance of the neighboring HOO(-) ligand. This ligand can be easily oxidized donating an electron to its partner ligand (H2O2). In an analogous case, when the central ion in the catalyst is a transition metal, this ion changing its oxidation state can donate an electron to the coordinated H2O2

Complexation of trichlorosalicylic acids by alkaline and first row transition metals as a switch for their antibacterial activity

KAUST Repository

Kumar, Vijay; Chawla, Mohit; Cavallo, Luigi; Basit Wani, Abdul; Manhas, Anu; Kaur, Sukhmanpreet; Poater, Albert; Chadar, Hemlata; NirajUpadhyay

2017-01-01

3,5,6-trichlorosalicylic acid (TCSA) does not show a good antibacterial activity. In contrast, here metal complexes with TCSA have shown better antibacterial activity for selected bacterial strains with a good degree of selectivity. Amongst

PRODUCTION OF CATHODES AND HIGH PURITY TARGETS OF CHEMICALLY ACTIVE METALS BY MEANS OF ELECTRONIC-RAY MELTING

Directory of Open Access Journals (Sweden)

A. V. Alifanov

2007-01-01

Full Text Available The technical process of production and restoration of worn cathodes and targets of chemically active metals (Ti, Zr, V and others with the help of cathode ray in vacuum is developed. Regenerating of worn cathodes, targets is carried out by means of insertion in chill of worn base and successive cathode ray deposition on certain places of required quantity of metal (from 2 till 50mm.

Determination of trace elements in metallic materials by neutron activation analysis

International Nuclear Information System (INIS)

Grassi, B; La Vecchia, G M; Manera, S; Salvini, A; Zenoni, A

2006-01-01

The aim of the present paper is to verify the applicability of neutron activation analysis to a metallurgic problem as a possible alternative technique to the standard investigation methodologies. A first series of measurements was performed in order to check the feasibility of irradiation and counting over metallic samples. Some of the feared problems concerned an excessive activation of the matrix and the consequent difficulties in the spectrum interpretation, as well as the removal of the radioactive waste created by the irradiation. Afterwards, a second series of measurements was performed to collect results aimed at the solution of a specific metallurgic case. The tests were performed at the TRIGA MARK II reactor facility of the LENA (Laboratorio Energia Nucleare Applicata) Institute of the Pavia University

Heavy metal contamination of agricultural soils affected by mining activities around the Ganxi River in Chenzhou, Southern China.

Science.gov (United States)

Ma, Li; Sun, Jing; Yang, Zhaoguang; Wang, Lin

2015-12-01

Heavy metal contamination attracted a wide spread attention due to their strong toxicity and persistence. The Ganxi River, located in Chenzhou City, Southern China, has been severely polluted by lead/zinc ore mining activities. This work investigated the heavy metal pollution in agricultural soils around the Ganxi River. The total concentrations of heavy metals were determined by inductively coupled plasma-mass spectrometry. The potential risk associated with the heavy metals in soil was assessed by Nemerow comprehensive index and potential ecological risk index. In both methods, the study area was rated as very high risk. Multivariate statistical methods including Pearson's correlation analysis, hierarchical cluster analysis, and principal component analysis were employed to evaluate the relationships between heavy metals, as well as the correlation between heavy metals and pH, to identify the metal sources. Three distinct clusters have been observed by hierarchical cluster analysis. In principal component analysis, a total of two components were extracted to explain over 90% of the total variance, both of which were associated with anthropogenic sources.

Effect of detergents, trypsin, and bivalent metal ions on interfacial activation and functioning of phospholipase D.

Science.gov (United States)

Madyarov, Sh R

2014-07-01

The effects of detergents, trypsin, and bivalent metal ions on production of phosphatidic and lysophosphatidic acids by the action of phospholipase D (PLD) on lecithin and lysolecithin were studied. It was found that these reaction products and dodecyl sulfate ions activate PLD, whereas other anionic detergents are less effective. A protective effect of the functioning enzyme against its hydrolytic inactivation by trypsin was found. Bivalent metal ions can be arranged in the following sequence by their ability to activate PLD in the hydrolysis of lecithin and lysolecithin: Ca2+>Sr2+>Ba2+>Mg2+. These results are considered in relation to a proposed mechanism of activation and functioning of PLD with the participation of clusters of phosphatidates and lysophosphatidates. Such Me2+-induced formation of rafts or microdomains from the products of hydrolysis of phospholipids can rationalize not only PLD activation and self-regulation, but also the action of this mechanism on other components and properties of biomembranes. PLD and other lipolytic enzymes can be classified as lateral vector enzymes.

In Vitro Antioxidant versus Metal Ion Chelating Properties of Flavonoids: A Structure-Activity Investigation

Science.gov (United States)

Cherrak, Sabri Ahmed; Mokhtari-Soulimane, Nassima; Berroukeche, Farid; Bensenane, Bachir; Cherbonnel, Angéline; Merzouk, Hafida; Elhabiri, Mourad

2016-01-01

Natural flavonoids such as quercetin, (+)catechin and rutin as well as four methoxylated derivatives of quercetin used as models were investigated to elucidate their impact on the oxidant and antioxidant status of human red blood cells (RBCs). The impact of these compounds against metal toxicity was studied as well as their antiradical activities with DPPH assay. Antihemolytic experiments were conducted on quercetin, (+)catechin and rutin with excess of Fe, Cu and Zn (400 μM), and the oxidant (malondialdehyde, carbonyl proteins) and antioxidant (reduced glutathione, catalase activity) markers were evaluated. The results showed that Fe and Zn have the highest prooxidant effect (37 and 33% of hemolysis, respectively). Quercetin, rutin and (+)catechin exhibited strong antioxidant properties toward Fe, but this effect was decreased with respect to Zn ions. However, the Cu showed a weak antioxidant effect at the highest flavonoid concentration (200 μM), while a prooxidant effect was observed at the lowest flavonoid concentration (100 μM). These results are in agreement with the physico-chemical and antiradical data which demonstrated that binding of the metal ions (for FeNTA: (+)Catechin, KLFeNTA = 1.6(1) × 106 M-1 > Rutin, KLFeNTA = 2.0(9) × 105 M-1 > Quercetin, KLFeNTA = 1.0(7) × 105 M-1 > Q35OH, KLFeNTA = 6.3(8.7) × 104 M-1 > Quercetin3’4’OH and Quercetin 3OH, KLFeNTA ~ 2 × 104 M-1) reflects the (anti)oxidant status of the RBCs. This study reveals that flavonoids have both prooxidant and antioxidant activity depending on the nature and concentration of the flavonoids and metal ions. PMID:27788249

NOx reduction over metal-ion exchanged novel zeolite under lean conditions. Activity and hydrothermal stability

International Nuclear Information System (INIS)

Subbiah, Ayyappan; Gujar, Amit; Price, Geoffrey L.; Cho, Byong K.; Blint, Richard J.; Yie, Jae E.

2003-01-01

Zeolite SUZ-4 was synthesized and tested for its hydrothermal stability using a standard aging procedure coupled with NMR spectroscopy, and was identified as a promising support for lean-NO x catalysts for high temperature applications. Various metals such as Cu, Ag, Fe, Co were ion exchanged onto the SUZ-4 zeolite, and their catalytic activity for NO/NO x conversion was measured in the presence of excess oxygen using ethylene as the reducing agent. Among the metal-ions exchanged, copper proved to be the best metal cation for lean-NO x catalysis with the optimum level of exchange at 29-42%. The optimized, fresh Cu/SUZ-4 catalyst achieved 70-80% of NO/NO x conversion activity over a wide range of temperature from 350 to 600C with the maximum conversion temperature at 450C. The presence of H 2 O and SO 2 reduced the NO/NO x conversion by about 30% of the fresh Cu/SUZ-4 catalyst due possibly to the blocking of active sites for NO/NO x adsorption. Substitution of gasoline vapor for ethylene as the reductant improved the NO x reduction activity of the fresh Cu/SUZ-4 catalyst at high temperatures above 350C. Aging the Cu/SUZ-4 catalyst resulted in a slight shift of activity profile toward higher temperatures, yielding an increase of NO conversion by 16% and a decrease of NO x conversion by 15% at 525C. The effect of H 2 O and SO 2 on the aged catalyst was to reduce the NO activity by 20% and NO x activity by 30% at 500C. The effect of space velocity change was not significant except in the low temperature range where the reaction light-off occurs. Adsorption/desorption measurements indicate that aging Cu/SUZ-4 results in partial migration/agglomeration of Cu particles in the pores thereby reducing the NO/NO x activity. Overall, the NO x conversion efficiency of Cu/SUZ-4, for both fresh and aged, is much better than the benchmark Cu/ZSM-5 in the presence of H 2 O and/or SO 2

Application of the quantitative autoradiography for determination of specific activity of labelled non-metallic inclusions

International Nuclear Information System (INIS)

Kowalczyk, J.T.; Wilczynski, A.W.

1983-01-01

The knowledge of specific activity of labelled non-metallic inclusions, i.e. the knowledge of the content of the radiotracer in a single inclusion, allows to obtain new information about the mechanism and the kinetics of steel deoxidation. In order to determine this specific activity quantitative autoradiography was used. Fo; this purpose, various standards of aluminium oxides with different amounts of cerium oxide Ce 2 O 3 and an aluminium-cerium alloy were prepared. The standards and the alloy were activated with thermal neutrons. Then several autoradiographs were made for these standards (ORWO AF-3 films were used). The autoradiographs served as the basis for evaluation of the standardization curves: optical density versus dimension of particles for a constant cerium concentration; optical density versus concentration of cerium for a constant dimension of particle. The samples of liquid steel were deoxidated with Al-Ce alloy. After labelled non-metallic inclusions had been isolated, the autoradiographs were made under the same conditions as for the standards. The standardization curves were used to determine the cerium content in the single inclusions. (author)

Biologically active compounds of semi-metals

Czech Academy of Sciences Publication Activity Database

Řezanka, Tomáš; Sigler, Karel

2008-01-01

Roč. 69, č. 3 (2008), s. 585-606 ISSN 0031-9422 Institutional research plan: CEZ:AV0Z50200510 Keywords : semi-metals * boron * silicon Subject RIV: CE - Biochemistry Impact factor: 2.946, year: 2008

Effects of heavy metals and phenol on the operation of sequencing batch reactor added activated carbon

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Hoon; Lim, Ji Hun; Park, Chul Hwan; Lee, Jin Won [Dept. of Chemical Engineering, Kwangwoon University, Seoul (Korea); Kim, Sang Yong [Korea Institute of Industrial Technology (Korea); Park, Jin Yong [Dept. of Environmental Engineering, Hallym University (Korea); Lee, Yong Myun [Osung Envi-Tech Company (Korea)

2000-04-01

The process of sequencing batch reactor(SBR) added the activated carbon were studied. To investigate the influence of the activated carbon on the treatment of organic materials and the effects of heavy metals on the process, three different kinds of granular activated carbons(GAC) were tested. Teh decrease of SCOD(soluble chemical oxygen demand) was measured at the different concentrations of the activated carbon. Synergistic effects of GAC on the biological activity in the SBR were confirmed from the data comparing adsorbed loadings with apparent loadings. When SBR was operated with GAC, the efficiency of wastewater treatment increased 16%. By comparing the adsorbed amount of SCOD estimated from Freundlich isotherm and the decrease of apparent loading, biological synergistic effect was confirmed. The inhibition of SBR performance from heavy metals or toxic chemicals could be reduced when GAC was added into the SBR process. Pb, Cd, Cr, and phenol were tested as typical inhibitors. When 10mg/L inhibitor was introduced into the SBR process which includes 500 mg/L GAC, the efficiency was increased as 32.6%, 27.2%, 22.3%, and 9.4%, respectively. 22 refs., 13 figs., 3 tabs.