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Sample records for coprecipitation adsorption filtration

  1. New trends on liquid effluent treatments: coprecipitation, adsorption, filtration, photo-catalysis, a complementary association of innovative tools

    Energy Technology Data Exchange (ETDEWEB)

    Barre, Yves [CEA, DEN, MAR, DTCD, SPDE, Laboratoire des Procedes Avances de Decontamination, 30207 Bagnols sur Ceze (France); Pacary, Vincent [CEA, DEN, MAR, DRCP, SCPS, LCSE, 30207 Bagnols sur Ceze (France); Schrive, Luc [CEA, DEN, MAR, DTCD, SPDE, Laboratoire des Fluides Supercritiques et Membranes, 30207 Bagnols sur Ceze (France); Guibal, Eric [Ecole des Mines d' Ales, Centre de Recherche LGEI, 6 avenue de Clavieres, 30319 Ales Cedex (France)

    2009-06-15

    The ever increasing pressure to reduce the release of radioactive and other toxic substances into environment requires constant improvement/upgrading of processes and technologies for treatment and conditioning of liquid radioactive wastes. The extensive research is carried out on various processes including ion exchange, sorption, coprecipitation, membrane separation and photo-catalytic degradation of organics substances. A judicious combination of the processes is being pursued to meet the end objectives of improved decontamination and waste volume reduction. In a previous study, an elaborated model is proposed to predict the radioactive strontium decontamination factor of nuclear waste solutions which can be realized by using a coprecipitation process with barium sulphate. Simulations of the coprecipitation of strontium ions with barium sulphate have been performed in continuous and semibatch reactors. Thanks to these simulations, laws of the treatment efficiency variation as a function of several process parameters (mean residence time, stirring speed, concentration) have been determined and experimentally verified. This study leads to the determination of optimal treatment conditions. Three apparatus (recycling apparatus, fluidized bed and reactor/settling tank) providing these optimal conditions have been successfully tested and offered significant outlooks for the reduction of the residual sludge volume. Since the development of new ceramic membranes with large filtration area and their long term use verification in conventional water purification fields, these membrane processes have been adopted by the nuclear industry as a viable alternative treatment method for liquid radioactive wastes. Ion exchange is one of the most common and effective treatment methods for liquid radioactive. Spent ion exchange resins are considered to be problematic waste that requires precautions during its immobilization to meet the acceptance criteria for disposal. Efforts to

  2. Properties of Fe-organic matter associations via coprecipitation versus adsorption.

    Science.gov (United States)

    Chen, Chunmei; Dynes, James J; Wang, Jian; Sparks, Donald L

    2014-12-01

    The association of organic matter (OM) with minerals is recognized as the most important stabilization mechanism for soil organic matter. This study compared the properties of Fe-OM complexes formed from adsorption (reaction of OM to postsynthesis ferrihydrite) versus coprecipitation (formation of Fe solids in the presence of OM). Coprecipitates and adsorption complexes were synthesized using dissolved organic matter (DOM) extracts from a forest little layer at varying molar C/Fe ratios of 0.3-25.0. Sample properties were studied by N2 gas adsorption, XRD, FTIR, Fe EXAFS, and STXM-NEXAFS techniques. Coprecipitation resulted in much higher maximum C contents (∼130 mg g(-1) C difference) in the solid products than adsorption, which may be related to the formation of precipitated insoluble Fe(III)-organic complexes at high C/Fe ratios in the coprecipitates as revealed by Fe EXAFS analysis. Coprecipitation led to a complete blockage of mineral surface sites and pores with ≥177 mg g(-1) C and molar C/Fe ratios ≥2.8 in the solid products. FTIR and STXM-NEXAFS showed that the coprecipitated OM was similar in composition to the adsorbed OM. An enrichment of aromatic C was observed at low C/Fe ratios. Association of carboxyl functional groups with Fe was shown with FTIR and STXM-NEXAFS analysis. STXM-NEXAFS analysis showed a continuous C distribution on minerals. Desorption of the coprecipitated OM was less than that of the adsorbed OM at comparable C/Fe ratios. These results are helpful to understand C and Fe cycling in the natural environments with periodically fluctuating redox conditions, where coprecipitation can occur.

  3. Properties and reactivity of Fe-organic matter associations formed by coprecipitation versus adsorption: Clues from arsenate batch adsorption

    Science.gov (United States)

    Mikutta, Robert; Lorenz, Dennis; Guggenberger, Georg; Haumaier, Ludwig; Freund, Anja

    2014-11-01

    Ferric oxyhydroxides play an important role in controlling the bioavailability of oxyanions such as arsenate and phosphate in soil. Despite this, little is known about the properties and reactivity of Fe(III)-organic matter phases derived from adsorption (reaction of organic matter (OM) to post-synthesis Fe oxide) versus coprecipitation (formation of Fe oxides in presence of OM). Coprecipitates and adsorption complexes were synthesized at pH 4 using two natural organic matter (NOM) types extracted from forest floor layers (Oi and Oa horizon) of a Haplic Podzol. Iron(III) coprecipitates were formed at initial molar metal-to-carbon (M/C) ratios of 1.0 and 0.1 and an aluminum (Al)-to-Fe(III) ratio of 0.2. Sample properties were studied by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), N2 gas adsorption, dynamic light scattering, and electrophoretic mobility measurements. Arsenic [As(V)] adsorption to Fe-OM phases was studied in batch experiments (168 h, pH 4, 100 μM As). The organic carbon (OC) contents of the coprecipitates (82-339 mg g-1) were higher than those of adsorption complexes (31 and 36 mg g-1), leading to pronounced variations in specific surface area (9-300 m2 g-1), average pore radii (1-9 nm), and total pore volumes (11-374 mm3 g-1) but being independent of the NOM type or the presence of Al. The occlusion of Fe solids by OM (XPS surface concentrations: 60-82 atom% C) caused comparable pHPZC (1.5-2) of adsorption complexes and coprecipitates. The synthesis conditions resulted in different Fe-OM association modes: Fe oxide particles in 'M/C 0.1' coprecipitates covered to a larger extent the outermost aggregate surfaces, for some 'M/C 1.0' coprecipitates OM effectively enveloped the Fe oxides, while OM in the adsorption complexes primarily covered the outer aggregate surfaces. Despite of their larger OC contents, adsorption of As(V) was fastest to coprecipitates formed at low Fe availability (M/C 0.1) and facilitated by desorption of weakly

  4. Arsenate and cadmium co-adsorption and co-precipitation on goethite

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei [Environment Research Institute, Shandong University, Jinan 250100 (China); Lv, Jitao; Luo, Lei [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Yang, Kun [Department of Environmental Science, Zhejiang University, Hangzhou 310058 (China); Lin, Yongfeng; Hu, Fanbao [Environment Research Institute, Shandong University, Jinan 250100 (China); Zhang, Jing [State Key Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Shuzhen, E-mail: szzhang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2013-11-15

    Highlights: • As enhances Cd adsorption amount on goethite. • Cd fixed through precipitation is more difficult to get released. • As in co-precipitates is easier to release than in its adsorption complexes. -- Abstract: Arsenate (As(V), AsO{sub 4}{sup 3−}) and cadmium (Cd) are among the toxic elements of most concern. Their sorption behaviors on goethite were studied by batch experiments (pH edges, isotherms and kinetics) and X-ray diffraction (XRD). Arsenic coordination environment was explored by X-ray absorbance fine structure (EXAFS) analysis. Sorption isotherms of both As(V) and Cd on goethite could be divided into the adsorption-dominated and precipitation-dominated parts, while their sorption showed different pH-dependency and sorption reversibility. Cadmium adsorption was enhanced in the presence of AsO{sub 4}{sup 3−}, which could be explained by the decrease in the electrostatic potential due to the sorption of AsO{sub 4}{sup 3−} and the formation of a ternary Cd–As(V)–goethite complex. Based on the EXAFS study, AsO{sub 4}{sup 3−} adsorbed on goethite mainly formed bidentate–binuclear complex. The high loadings of Cd changed the As(V)–Fe distance and its coordination number. However, Cd did not affect the As(V) adsorption amount in the adsorption-dominated region. When As(V) and Cd formed co-precipitates, their sorption amounts were both increased. The formation of co-precipitates decreased the mobility of Cd but increased the mobility of As(V) because less As(V) was sorbed on goethite through surface complexation. This study will provide better understandings on As(V) and Cd transport and useful information on their remediation strategies.

  5. 77 FR 38857 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal...

    Science.gov (United States)

    2012-06-29

    ... COMMISSION Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal..., Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal Atmosphere Cleanup Systems..., entitled, ``Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of...

  6. 76 FR 82323 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units

    Science.gov (United States)

    2011-12-30

    ... COMMISSION Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units AGENCY: Nuclear...-1274, ``Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of....'' This guide applies to the design, inspection, and testing of air filtration and iodine adsorption...

  7. The Use of Coupled Plasma Filtration Adsorption in Traumatic Rhabdomyolysis

    Directory of Open Access Journals (Sweden)

    Mario Pezzi

    2017-01-01

    Full Text Available Severe musculoskeletal injuries induce the release of sarcoplasmic elements such as muscle enzymes, potassium, and myoglobin in the systemic circulation. The circulating myoglobin damages the glomerulus and renal tubules. Conventional haemodialysis is not able to remove myoglobin, due to its high molecular weight (17,8 kilodaltons [kDa]. We treated four traumatic rhabdomyolysis patients with Coupled Plasma Filtration Adsorption (CPFA in order to remove myoglobin followed by 14 hours of Continuous Veno-Venous Hemofiltration (CVVH. During the treatment, all patients showed clinical improvement with a decrease in muscular (creatine kinase [CK] and myoglobin and renal (creatinine and potassium damage indices. One patient, in spite of full renal recovery, died of cerebral haemorrhage on the 26th day of hospital stay.

  8. 77 FR 60481 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident...

    Science.gov (United States)

    2012-10-03

    ... COMMISSION Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident..., and Testing Criteria for Air Filtration and Adsorption Units of Post-accident Engineered-Safety... design, inspection, and testing of air filtration and iodine adsorption units of...

  9. Simulations of Microbial-Enhanced Oil Recovery: Adsorption and Filtration

    DEFF Research Database (Denmark)

    Nielsen, Sidsel Marie; Nesterov, Igor; Shapiro, Alexander

    2014-01-01

    In the context of microbial-enhanced oil recovery (MEOR) with injection of surfactant-producing bacteria into the reservoir, different types of bacteria attachment and growth scenarios are studied using a 1D simulator. The irreversible bacteria attachment due to filtration similar to the deep bed...... applied to filtration model provides formation of two oil banks during recovery. This feature is not reproduced by application of REA model or DBF with growth in attached phase. This makes it possible to select a right model based on the qualitative analysis of the experimental data. A criterion...

  10. Comparison of arsenic co-precipitation and adsorption by iron minerals and the mechanism of arsenic natural attenuation in a mine stream.

    Science.gov (United States)

    Park, Jin Hee; Han, Young-Soo; Ahn, Joo Sung

    2016-12-01

    Mine stream precipitate collected from Ilkwang mine, Korea, contained high concentrations of arsenic (As), while water collected from the same site had negligible As concentrations, indicating natural attenuation of As occurred in the mine stream. The mechanism of attenuation was explained by comparison of X-ray absorption near edge structure (XANES) of As(V) co-precipitated with or adsorbed to iron (Fe) minerals in mine precipitates. Arsenic in the mine precipitate was present as As(V) and schwertmannite was the main Fe mineral. Arsenic co-precipitation with schwertmannite was the major mechanism of As removal in the mine stream, followed by As adsorption by goethite and As co-precipitation with ferrihydrite. Schwertmannite and ferrihydrite were formed in acid mine drainage and As was incorporated in their structure during formation. Additionally, schwertmannite and ferrihydrite may transform to goethite with As adsorbed onto the goethite surface. Based on the results of batch experiments of As co-precipitation and adsorption, co-precipitation of As with ferrihydrite and schwertmannite was the most effective As sequestration mechanism in the removal of As(V) from acid mine drainage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Adsorptive removal of nitrilotris(methylenephosphonic acid) antiscalant from membrane concentrates by iron-coated waste filtration sand.

    Science.gov (United States)

    Boels, L; Tervahauta, T; Witkamp, G J

    2010-10-15

    Iron-coated waste filtration sand was investigated as a low-cost adsorbent for the removal of nitrilotris(methylenephosphonic acid) (NTMP) from membrane concentrates. The adsorption of this phosphonate-based antiscalant on this material was measured and compared with two commercially available anion exchange resins and activated carbon. Comprehensive adsorption experiments were conducted in several synthetic concentrate solutions and in a concentrate collected from a full scale nano-filtration brackish water desalination plant. The effect of pH, ionic strength and the presence of competitive anions on the equilibrium adsorption were investigated. The results showed that, in contrast to the anion exchange resins, the adsorption on coated filtration sand is not suppressed at increasing ionic strength and is much less affected by the competitive anions carbonate and sulphate. The adsorption decreased slightly when the pH was raised from 7.0 to 8.0. The adsorption isotherms in the real nano-filtration concentrate, measured in the concentration interval of 5-50 mg dm(-1) NTMP, showed that the maximum adsorption capacity of coated filtration sand was 4.06 mg g(-1). The adsorption capacity per unit mass of the adsorbents at low NTMP concentration (12.5 mg dm(-3)) followed the decreasing order Amberlite IRA-410>coated filtration sand>Amberlite IRA-900>Norit SAE Super. This demonstrates that the use of iron-coated waste filtration sand offers a promising means for the removal of NTMP from membrane concentrates.

  12. Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials.

    Science.gov (United States)

    Opiso, Einstine; Sato, Tsutomu; Yoneda, Tetsuro

    2009-10-15

    Pollution caused by boric acid and toxic anions such as As(V), Cr(VI) and Se(VI) is hazardous to human health and environment. The sorption characteristics of these environmentally significant ionic species on allophane-like nanoparticles were investigated in order to determine whether allophane can reduce their mobility in the subsurface environment at circum-neutral pH condition. Solutions containing 100 or 150 mmol of AlCl(3)x6H(2)O were mixed to 100 mmol of Na(4)SiO(4) and the pH were adjusted to 6.4+/-0.3. The mineral suspensions were shaken for 1h and incubated at 80 degrees C for 5 days. Appropriate amounts of As, B, Cr and Se solutions were added separately during and after allophane precipitation. The results showed that As(V) and boric acid can be irreversibly fixed during co-precipitation in addition to surface adsorption. However, Cr(VI) and Se(VI) retention during and after allophane precipitation is mainly controlled by surface adsorption. The structurally fixed As(V) and boric acid were more resistant to release than those bound on the surface. The sorption characteristics of oxyanions and boric acid were also influenced by the final Si/Al molar ratio of allophane in which Al-rich allophane tend to have higher uptake capacity. The overall results of this study have demonstrated the role of allophane-like nanoparticles and the effect of its Si/Al ratio on As, B, Cr and Se transport processes in the subsurface environment.

  13. Uranium Isotope Fractionation during Adsorption, (Co)precipitation, and Biotic Reduction.

    Science.gov (United States)

    Dang, Duc Huy; Novotnik, Breda; Wang, Wei; Georg, R Bastian; Evans, R Douglas

    2016-12-06

    Uranium contamination of surface environments is a problem associated with both U-ore extraction/processing and situations in which groundwater comes into contact with geological formations high in uranium. Apart from the environmental concerns about U contamination, its accumulation and isotope composition have been used in marine sediments as a paleoproxy of the Earth's oxygenation history. Understanding U isotope geochemistry is then essential either to develop sustainable remediation procedures as well as for use in paleotracer applications. We report on parameters controlling U immobilization and U isotope fractionation by adsorption onto Mn/Fe oxides, precipitation with phosphate, and biotic reduction. The light U isotope ((235)U) is preferentially adsorbed on Mn/Fe oxides in an oxic system. When adsorbed onto Mn/Fe oxides, dissolved organic carbon and carbonate are the most efficient ligands limiting U binding resulting in slight differences in U isotope composition (δ(238)U = 0.22 ± 0.06‰) compared to the DOC/DIC-free configuration (δ(238)U = 0.39 ± 0.04‰). Uranium precipitation with phosphate does not induce isotope fractionation. In contrast, during U biotic reduction, the heavy U isotope ((238)U) is accumulated in reduced species (δ(238)U up to -1‰). The different trends of U isotope fractionation in oxic and anoxic environments makes its isotope composition a useful tracer for both environmental and paleogeochemical applications.

  14. Phosphate adsorption from wastewater using zirconium (IV) hydroxide: Kinetics, thermodynamics and membrane filtration adsorption hybrid system studies.

    Science.gov (United States)

    Johir, M A H; Pradhan, M; Loganathan, P; Kandasamy, J; Vigneswaran, S

    2016-02-01

    Excessive phosphate in wastewater should be removed to control eutrophication of water bodies. The potential of employing amorphous zirconium (Zr) hydroxide to remove phosphate from synthetic wastewater was studied in batch adsorption experiments and in a submerged membrane filtration adsorption hybrid (MFAH) reactor. The adsorption data satisfactorily fitted to Langmuir, pseudo-first order and pseudo-second order models. Langmuir adsorption maxima at 22 °C and pHs of 4.0, 7.1, and 10.0 were 30.40, 18.50, and 19.60 mg P/g, respectively. At pH 7.1 and temperatures of 40 °C and 60 °C, they were 43.80 and 54.60 mg P/g, respectively. The thermodynamic parameters, ΔG° and ΔS° were negative and ΔH° was positive. FTIR, zeta potential and competitive phosphate, sulphate and nitrate adsorption data showed that the mechanism of phosphate adsorption was inner-sphere complexation. In the submerged MFAH reactor experiment, when Zr hydroxide was added at doses of 1-5 g/L once only at the start of the experiment, the removal of phosphate from 3 L of wastewater containing 10 mg P/L declined after 5 h of operation. However, when Zr hydroxide was repeatedly added at 5 g/L dose every 24 h, satisfactory removal of phosphate was maintained for 3 days.

  15. Membrane filtration of two sulphonamides in tertiary effluents and subsequent adsorption on activated carbon.

    Science.gov (United States)

    Hartig, C; Ernst, M; Jekel, M

    2001-11-01

    The adsorption behaviour of two polar organic micropollutants (N-n-butylbenzenesulphonamide and sulphmethoxazole) onto powdered activated carbon (PAC) under competitive conditions prior to and after filtration with a tight ultrafiltration membrane was examined. The sulphonamides were spiked into microfiltered tertiary municipal effluent in microg L(-1) quantities. Ultrafiltration of these effluents resulted in better adsorbability for both the micropollutants and the background organic matter in the permeates compared to the feed waters. This behaviour seems to be caused by a reduced blocking of micropores by lower concentrations of high molecular weight compounds in membrane filtrates. A combined treatment of ultrafiltration prior to adsorption can therefore reduce the carbon demand for potentially harmful micropollutants in effluents.

  16. Cytokine filtration and adsorption during pre- and postdilution hemofiltration in four different membranes.

    Science.gov (United States)

    Bouman, C S; van Olden, R W; Stoutenbeek, C P

    1998-01-01

    In the present in vitro study we investigated filtration and adsorption of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8) during predilution and postdilution hemofiltration with polysulfone, polyacrylonitrile, polyamide and cellulose triacetate membranes. The median sieving coefficient (SC) for all membranes was 0.0 for TNF-alpha, below 0.15 for IL-6 and below 0.15 for IL-8 during postdilution hemofiltration. Differences in SC between filtration modes were less than 0.05. Maximal differences in SC between membranes were 0.11 for IL-6, 0.0 for TNF-alpha, and 0.11 for IL-8. The progressive decrease in cytokine concentrations was identical between the two filtration modes and most pronounced with the polyacrylonitrile membrane (reduction 77% for IL-6, 39% for TNF-alpha and 95% for IL-8 after 4 h of hemofiltration). The relative contribution of adsorption to the reduction in cytokines was 100% for TNF-alpha for all membranes, between 53 (cellulose triacetate) and 83% (polyacrylonitrile) for IL-6, and for IL-8 between 0 (polysulfone) and 100% (polyacrylonitrile). In conclusion, the reduction in TNF-alpha, IL-6 and IL-8 was most impressive with the polyacrylonitrile membrane after 4 h of hemofiltration and was largely due to adsorption. Adsorption of TNF-alpha, IL-6 and IL-8 was also seen with the other membranes. None of the membranes filtered TNF-alpha. Sieving of IL-6 and IL-8 was low for all membranes with only marginal differences between membranes or between filtration modes.

  17. Removal of two cationic dyes from a textile effluent by filtration-adsorption on wood sawdust.

    Science.gov (United States)

    Laasri, Laila; Elamrani, M Khalid; Cherkaoui, Omar

    2007-06-01

    Wastewater from textile industry contains various contaminants such as dyes, surfactants and heavy metals. Textile dyes have synthetic origin and complex aromatic molecular structures that make them difficult to biodegrade when discharged in the ecosystem. The objective of this study was to examine the decolourisation of textile effluents containing cationic dyes by filtration-adsorption on wood sawdust from two different origins; fir as an example of a conifer tree, and beech as an example of a deciduous one, and to explain the adsorption mechanism. The process of dye removal was applied to a synthetic effluent in batch mode. Adsorption experiments were performed by suspending sawdust in the effluent and analyzing the supernatant by spectrophotometry. The effectiveness of the treatment process was evaluated by measuring coloration. Experimental results showed a significant potential for wood sawdust, especially coniferous sawdust, to remove cationic dyes from textile effluents. Adsorption kinetics was influenced by the initial dye concentration, nature and amount of sorbent as well as sorbent particle size. The adsorption followed a pseudo first-order kinetics. For both basic dyes, the Langmuir adsorption equation showed a better fit than the Freundlich equation. Filtration-adsorption using an inexpensive and readily available biosorbent provided an attractive alternative treatment for dye removal, and it does not generate any secondary pollution. Recommendations and Perspectives. Laboratory studies provide promising perspectives for the utilization of wood sawdust as renewable adsorbent for reducing pollution while enhancing the reuse of textile effluents. However, the treatment process needs to be applied to the other textile dye classes in order to be used on an industrial scale.

  18. Advanced phosphorus removal from membrane filtrates by adsorption on activated aluminium oxide and granulated ferric hydroxide.

    Science.gov (United States)

    Genz, Arne; Kornmüller, Anja; Jekel, Martin

    2004-09-01

    The advanced phosphorus (P) removal by adsorption was studied for its suitability as a post-treatment step for membrane bioreactor (MBR) effluents low in P concentration and particle content. Two commercial adsorbents, granulated ferric hydroxide (GFH) and activated aluminium oxide (AA), were studied in batch tests and lab-scale filter tests for P adsorption in MBR filtrates. GFH showed a higher maximum capacity for phosphate and a higher affinity at low P concentrations compared to AA. Competition by inorganic ions was negligible for both adsorbents at the original pH (8.2). When equilibrium P concentrations exceeded 2 mg L(-1) in the spiked MBR filtrates, a precipitation of calcium phosphates occurred additionally to adsorption. During column studies the effluent criteria of 50 microgL(-1) P was reached after a throughput of 8000 bed volumes for GFH and 4000 for AA. Dissolved organic carbon appears to be the strongest competitor for adsorption sites. A partial regeneration and reloading of both adsorbents could be achieved by the use of sodium hydroxide.

  19. Experimental study of germanium adsorption on goethite and germanium coprecipitation with iron hydroxide: X-ray absorption fine structure and macroscopic characterization

    Science.gov (United States)

    Pokrovsky, O. S.; Pokrovski, G. S.; Schott, J.; Galy, A.

    2006-07-01

    Adsorption of germanium on goethite was studied at 25 °C in batch reactors as a function of pH (1-12), germanium concentration in solution (10 -7 to 0.002 M) and solid/solution ratio (1.8-17 g/L). The maximal surface site density determined via Ge adsorption experiments at pH from 6 to 10 is equal to 2.5 ± 0.1 μmol/m 2. The percentage of adsorbed Ge increases with pH at pH Model (SCM) which implies a constant capacitance of the electric double layer and postulates the presence of two Ge complexes, >FeO-Ge(OH)30 and >FeO-GeO(OH)2-, at the goethite-solution interface. Coprecipitation of Ge with iron oxy(hydr)oxides formed during Fe(II) oxidation by atmospheric oxygen or by Fe(III) hydrolysis in neutral solutions led to high Ge incorporations in solid with maximal Ge/Fe molar ratio close to 0.5. The molar Ge/Fe ratio in precipitated solid is proportional to that in the initial solution according to the equation (Ge/Fe) solid = k × (Ge/Fe) solution with 0.7 ⩽ k ⩽ 1.0. The structure of adsorbed and coprecipitated Ge complexes was further characterized using XAFS spectroscopy. In agreement with previous data on oxyanions adsorption on goethite, bi-dentate bi-nuclear surface complexes composed of tetrahedrally coordinated Ge attached to the corners of two adjacent Fe octahedra represent the dominant contribution to the EXAFS signal. Coprecipitated samples with Ge/Fe molar ratios >0.1, and samples not aged in solution (hydroxide at Ge/Fe molar ratio ⩽0.0001. These conditions are likely to be met in many superficial aquatic environments at the contact of anoxic groundwaters with surficial oxygenated solutions. Adsorption and coprecipitation of Ge with solid Fe oxy(hydr)oxides and organo-mineral colloids and its consequence for Ge/Si fractionation and Ge geochemical cycle are discussed.

  20. Coupled plasma filtration adsorption in experimental peritonitis-induced septic shock.

    Science.gov (United States)

    Sykora, Roman; Chvojka, Jiri; Krouzecky, Ales; Radej, Jaroslav; Kuncova, Jitka; Varnerova, Veronika; Karvunidis, Thomas; Novak, Ivan; Matejovic, Martin

    2009-05-01

    The coupled plasma filtration adsorption (CPFA) was developed as an adsorptive hemopurification method aimed at nonselective removal of circulating soluble mediators potentially involved in the pathogenesis of sepsis. We hypothesized that this nonselective hemopurification could protect from detrimental consequences of long-term, volume-resuscitated porcine septic shock. In 16 anesthetized, mechanically ventilated, and instrumented pigs, the hyperdynamic septic shock secondary to peritonitis was induced by intraperitoneally inoculating feces and maintained for 22 h with fluid resuscitation and norepinephrine infusion as needed to maintain MAP above 65 mmHg. After 12 h of peritonitis, animals were randomized to receive either supportive treatment (control, n = 8) or CPFA treatment (CPFA, n = 8). Systemic, hepatosplanchnic, and renal hemodynamics; oxygen exchange; energy metabolism (lactate/pyruvate and ketone body ratios); ileal mucosal and renal cortex microcirculation; systemic inflammation (TNF-alpha, IL-6); nitrosative/oxidative stress (thiobarbituric acid reactive species, nitrates + nitrites); and endothelial/coagulation dysfunction (asymmetric dimethylarginine, von Willebrand factor, thrombin-antithrombin complexes, platelet count) were assessed before and 12, 18, and 22 h of peritonitis. Coupled plasma filtration adsorption neither delayed the development of hypotension nor reduced the dose of norepinephrine. The treatment failed to attenuate sepsis-induced alterations in microcirculation, surrogate markers of cellular energetics, endothelial injury, and systemic inflammation. Similarly, CPFA did not protect from lung and liver dysfunction and even aggravated sepsis-induced disturbances in coagulation and oxidative/nitrosative stress. In this porcine model of septic shock, the early treatment with CPFA was not capable of reversing the sepsis-induced disturbances in various biological pathways and organ systems. Both the efficacy and safety of this method

  1. NOM removal by adsorption and membrane filtration using heated aluminum oxide particles.

    Science.gov (United States)

    Cai, Zhenxiao; Kim, Jaeshin; Benjamin, Mark M

    2008-01-15

    Heated aluminum oxide particles (HAOPs) are a newly synthesized adsorbent with attractive properties for use in hybrid adsorption/membrane filtration systems. This study compared removal of natural organic matter (NOM) from water by adsorption onto HAOPs with that by adsorption onto powdered activated carbon (PAC) or coagulation with alum or ferric chloride (FeCl3); explored the overlap between the NOM molecules that preferentially adsorb to HAOPs and those that are removed by the more conventional approaches; and evaluated NOM removal and fouling in hybrid adsorbent/membrane systems. For equivalent molar doses of the trivalent metals, HAOPs remove more NOM, and NOM with higher SUVA254, than alum or FeCl3. Most of the HAOPs-nonadsorbable fraction of the NOM can be adsorbed by PAC; in fact, that fraction appears to be preferentially adsorbed compared to the average NOM in untreated water. Predeposition of the adsorbents on a microfiltration membrane improves system performance. For the water tested, at a flux of 100 L/m2-hr, predeposition of 11 mg/L PAC and 5 mg/L HAOPs (as Al3+) allowed the system to operate 5 times as long before the transmembrane pressure increased by 1 psi and to remove 10-20 times as much NOM as when no adsorbents were added.

  2. Study of the combining adsorption-micro filtration process for the treatment of coloured waters

    Energy Technology Data Exchange (ETDEWEB)

    Addaou, A.; Laajeb, A.; Lahsini, A.; Bentama, J.; Rodriguez, M. A.

    2012-11-01

    Generally textile effluents are highly coloured, contain non-biodegradable compounds and they have high content of solid wastes, comprising fibres and paper wastes. The discharge of such effluents in the environment is worrying for both toxicological and esthetical reasons. The aim of the present work is to study the performances of the combining micro filtration-adsorption process for the treatment of coloured waters. Methylene Blue (MB) was used as model compound. The effects of significant operating parameters such as transmembrane pressure (TMP) and bentonite concentration on the process performance characterized by flux and rejection factor were investigated. Experiments carried out with Methylene Blue solutions confirmed the potential of this combined process for the treatment of dyed waters. (Author) 13 refs.

  3. Increasing parvovirus filter throughput of monoclonal antibodies using ion exchange membrane adsorptive pre-filtration.

    Science.gov (United States)

    Brown, Arick; Bechtel, Charity; Bill, Jerome; Liu, Hui; Liu, Jun; McDonald, Dan; Pai, Satyan; Radhamohan, Asha; Renslow, Ryan; Thayer, Brooke; Yohe, Stefan; Dowd, Chris

    2010-07-01

    Pre-filtration using ion exchange membrane adsorbers can improve parvovirus filter throughput of monoclonal antibodies (mAbs). The membranes work by binding trace foulants, and although some antibody product also binds, yields > or =99% are easily achieved by overloading. Results show that foulant adsorption is dependent on pH and conductivity, but independent of scale and adsorber brand. The ability to use ion exchange membranes as pre-filters is significant because it provides a clean, well defined, chemically stable option for enhancing throughput. Additionally, ion exchange membranes facilitate characterization of parvovirus filter foulants. Examination of adsorber elution samples using sedimentation velocity analysis and SEC-MALS/QELS revealed the presence of high molecular weight species ranging from 8 to 13 nm in hydrodynamic radius, which are similar in size to parvoviruses and thus would be expected to plug the pores of a parvovirus filter. A study of two identical membranes in-series supports the hypothesis that the foulants are soluble, trace level aggregates in the feed. This study's significance lies in a previously undiscovered application of membrane chromatography, leading to a more cost effective and robust approach to parvovirus filtration for the production of monoclonal antibodies.

  4. Influence of adsorption versus coprecipitation on the retention of rice straw-derived dissolved organic carbon and subsequent reducibility of Fe-DOC systems

    Science.gov (United States)

    Sodano, Marcella; Lerda, Cristina; Martin, Maria; Celi, Luisella; Said-Pullicino, Daniel

    2016-04-01

    adsorption or coprecipitation, DOC was obtained by incubating a suspension of rice straw in water (straw-solution ratio of 1:30) under oxic conditions at 25° C for 30 days to simulate the decomposition of rice straw in the field. Increasing amounts of DOC were equilibrated (pH = 6) with a known mass of ferrihydrite (initial molar C:Fe ratios of 1, 5 and 10) to obtain surface coated Fe-DOC systems with increasing C loading. On the other hand, coprecipitates with similar initial C:Fe ratios were obtained by oxidation of a Fe(II) solution in the presence of increasing amounts of DOC at pH = 6. A natural Fe-DOC coprecipitate was also obtained by in situ sampling of a paddy soil solution from the topsoil during a cropping season, and subsequent oxidation in the laboratory. The surface and chemical properties of all substrates were subsequently evaluated and compared. We hereby present the first results of the influence of adsorption vs coprecipitation on the selective retention of DOC, structure and surface charge, as well as their susceptibility to chemical reduction with ascorbic acid.

  5. Investigation of optical, photocatalytic and physical adsorption of a new nanocomposite synthesized via a simple co-precipitation method

    Science.gov (United States)

    Sabet, Mohammad; Mohammadi, Marziyeh; Googhari, Fatemeh

    2017-03-01

    In this experimental work, different morphologies of the CdxZn1-xS/ZnO nanocomposite were synthesized via a simple co-precipitation method. The effect of Zn2+: Cd2+ mole ratio on the product size and morphology was investigated and it was found that the mole ratio has a significant effect on the morphology of the products. To study the crystallinity and purity of the product, X-ray diffraction (XRD) pattern was served. Scanning electron microscopy (SEM) was used to study the morphology of the products. The optical properties of the as-synthesized nanocomposites were studied by ultraviolet-visible (UV-Vis) spectra. Photocatalytic activity of the nanocomposite was carried out by decomposition of Acid Black 1 dye, and it was found after 60min, almost all the dye structure was decomposed under UV radiation. Finally, to study the nanocomposite performance in removing heavy metal ions from water, three different solutions containing Zn2+, Cd2+ and Pb2+ with 0.01 molar concentration were prepared in the aqueous medium and the absorption of them with the nanocomposite was investigated by atomic absorption spectroscopy (AAS). The results showed that the synthesized nanocomposite has a unique performance and it can remove almost 80% of heavy metal ions from the water.

  6. Palm Oil Mill Effluent Treatment Through Combined Process Adsorption and Membrane Filtration

    Directory of Open Access Journals (Sweden)

    Muhammad Said

    2016-08-01

    Full Text Available The growth in palm oil production also leads to an Increase in the production of palm oil mill effluent (POME. Nowadays, POME was treated using an open lagoon but this method is ineffectiveness in complying with the standards for water disposal. Therefore, efficient and cohesive treatment system is highly desired to ensure the final discharge of the treated water meets the effluent discharge standards. Initially, the POME was treated through adsorption, followed by UF membranes roomates were intended to reduce COD, TSS and turbidity up to 88%, 99%, and 98%, while the final treatment of RO membranes can reduce BOD, COD and color up to 92%, 98% and 99%. To determine the optimum condition of the RO membrane, response surface methodology (RSM was used. The results showed there was correlation between all key variables. POME concentration, trans-membrane pressure, pH and time would give significant effects in reducing the parameters in POME treatment with the optimum condition of 15.77% for POME concentration, 3.73 for pH, 0.5 bar trans-membrane pressure and 5 hours for filtration time. To predict COD removal, the results were analyzed by applying the artificial neural network (ANN to derive a mathematical model.

  7. Purification of olive mill wastewater phenols through membrane filtration and resin adsorption/desorption.

    Science.gov (United States)

    Zagklis, Dimitris P; Vavouraki, Aikaterini I; Kornaros, Michael E; Paraskeva, Christakis A

    2015-03-21

    Olive tree cultivation has a long history in the Mediterranean countries, and even today consists an important cultural, economic, and environmental aspect of the area. The production of olive oil through 3-phase extraction systems, leads to the co-production of large quantities of olive mill wastewater (OMW), with toxic compounds that inhibit its biodegradation. Membrane filtration has been used for the exploitation of this byproduct, through the isolation of valuable phenolic compounds. In the current work, a fraction of the waste occurring from a membrane process was used. More specifically the reverse osmosis concentrate, after a nanofiltration, containing the low-molecular-weight compounds, was further treated with resin adsorption/desorption. The non ionic XAD4, XAD16, and XAD7HP resins were implemented, for the recovery of phenols and their separation from carbohydrates. The recovered phenolic compounds were concentrated through vacuum evaporation reaching a final concentration of 378 g/L in gallic acid equivalents containing 84.8 g/L hydroxytyrosol.

  8. Part of plasmapheresis with plasma filtration adsorption combined with continuous hemodiafiltration in the treatment of severe acute liver failure

    Science.gov (United States)

    Li, Maoqin; Wang, Zhidong; Wang, Yining; Du, Changhong; Li, Songhai; Shi, Zaixiang; Lu, Bo

    2016-01-01

    The present study is a retrospective analysis of 11 cases with severe acute liver failure combined with multiple organ dysfunction syndrome (MODS) performed during the period June, 2012 to December, 2014. After part of plasmapheresis with plasma filtration adsorption combined with continuous hemodiafiltration treatment, good curative effects were obtained and the main clinical symptoms and biochemical index were significantly improved. Following treatment, 8 of the 11 patients survived at a survival rate of 72.7%, and 3 patients succumbed with a mortality of 27.3%. The results suggested that part of plasmapheresis with plasma filtration adsorption combined with continuous venovenous hemodiafiltration (CVVHDF) treatment is beneficial in the removal of metabolites and toxins. Additonally, it can effectively improve liver function and clinical symptoms, improve hepatic encephalopathy, correct the disorder of internal environment, and improve the prognosis of patients. PMID:27698760

  9. Continuous plasma filtration adsorption in treatment of severe infection-induced multiple organ dysfunction syndrome.

    Science.gov (United States)

    Yin, S L; Lan, C; Pei, H; Zu, Z Q

    2016-01-01

    Multiple organ dysfunction syndrome (MODS), a high-risk disease, has a fatality rate of 70%. To improve treatment of this disease, in recent years many scholars have explored the pathological and physiological changes of MODS. To observe the curative effect of continuous plasma filtration adsorption (CPFA) in the treatment of MODS, we selected 96 patients who were diagnosed with severe infection-induced MODS and were treated in the First Affiliated Hospital of Zhengzhou University between February 2012 and October 2014 and divided them into an observation group and a control group. Besides conventional treatment, the observation group was also given CFPA in combination with high volume hemofiltration (HVHF), while the control group only received HVHF. Changes of blood routine index, balance of electrolyte and acid-base as well as vital signs were observed before and after treatment. Also, blood, kidney and blood gas were examined. For all patients, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and C-reactive protein (CRP) were recorded at the start of treatment (0 h), and 5 h and 10 h after treatment. It was found that both therapies could lower blood urea nitrogen (BUN) and creatinine levels and maintain balance of electrolyte and acid-base, but had no obvious influence on leukocyte, blood platelet and hematocrit. In the observation group, PaO(2)/FiO(2) and mean arterial pressure (MAP) were significantly improved after surgery (P less than 0.05), while Acute Physiology and Chronic Health Evaluation (APACHE) II score had an obvious decrease (P less than 0.05). In contrast, the control group was observed with insignificantly changed PaO(2)/FiO(2), MAP and APACHE II score (P>0.05). TNF-α, IL-6 and CRP levels of the two groups had no statistically significant difference at the start of treatment (P>0.05), but TNF-α, IL-6 and CRP levels of the observation group became remarkably lower than those of the control group 5 h and 10 h after treatment (P less than

  10. Ultrasound efficiency in relation to sodium hypochlorite and filtration adsorption in microbial elimination in a water treatment plant

    Directory of Open Access Journals (Sweden)

    Antonio Roberto Crystal Bello

    2005-09-01

    Full Text Available Processes like ultrasound, chlorination and filtration-adsorption were compared to eliminate microorganisms and to adjust established parameters of public drinking water. A mini water treatment plant (WTP-CB, in pilot scale, was projected and built to evaluate each process influence as: decontamination, coagulation-flocculation, sedimentation and filtration. Total and fecal coliforms, Escherichia coli and heterotrophic bacteria and physic/chemical parameters were quantified from water. Ultrasound, chlorination and filtration-adsorption were efficient to inactivate and/or eliminate bacteria. Ultrasound decontamination in addition to coagulation-flocculation, sedimentation and filtration, could be considered as an alternative treatment water solution where prechlorination, coagulation-flocculation, sedimentation and filtration were used. The chlorination itself was efficient in inactivating bacteria despite of the coagulation-flocculation process; however, in the absence of the coagulation process, the resultant water did not achieve the established parameters. The filtration-adsorption was an important process to eliminate bacteria, showing that the filter retained particles, suspended solids, besides chemical substances and microorganisms.Comparou-se diferentes processos: ultra-som, cloração e filtração/adsorção para eliminação de microrganismos e adequação de outros parâmetros exigidos para água de abastecimento público. Para avaliar a influência de cada processo: desinfecção, coagulação/floculação, decantação e filtração foi projetada e construída uma Estação de Tratamento de Água (ETA-CB em escala piloto. Foram avaliados coliformes, bactérias heterotróficas e parâmetros físico/químicos. Ondas ultra-sônicas, cloração e filtração/adsorção mostraram-se eficientes na inativação e/ou eliminação de bactérias. O processo de desinfecção com ultra-som juntamente com a coagulação/floculação, decanta

  11. Combination of granular activated carbon adsorption and deep-bed filtration as a single advanced wastewater treatment step for organic micropollutant and phosphorus removal.

    Science.gov (United States)

    Altmann, Johannes; Rehfeld, Daniel; Träder, Kai; Sperlich, Alexander; Jekel, Martin

    2016-04-01

    Adsorption onto granular activated carbon (GAC) is an established technology in water and advanced wastewater treatment for the removal of organic substances from the liquid phase. Besides adsorption, the removal of particulate matter by filtration and biodegradation of organic substances in GAC contactors has frequently been reported. The application of GAC as both adsorbent for organic micropollutant (OMP) removal and filter medium for solids retention in tertiary wastewater filtration represents an energy- and space saving option, but has rarely been considered because high dissolved organic carbon (DOC) and suspended solids concentrations in the influent of the GAC adsorber put a significant burden on this integrated treatment step and might result in frequent backwashing and unsatisfactory filtration efficiency. This pilot-scale study investigates the combination of GAC adsorption and deep-bed filtration with coagulation as a single advanced treatment step for simultaneous removal of OMPs and phosphorus from secondary effluent. GAC was assessed as upper filter layer in dual-media downflow filtration and as mono-media upflow filter with regard to filtration performance and OMP removal. Both filtration concepts effectively removed suspended solids and phosphorus, achieving effluent concentrations of 0.1 mg/L TP and 1 mg/L TSS, respectively. Analysis of grain size distribution and head loss within the filter bed showed that considerable head loss occurred in the topmost filter layer in downflow filtration, indicating that most particles do not penetrate deeply into the filter bed. Upflow filtration exhibited substantially lower head loss and effective utilization of the whole filter bed. Well-adsorbing OMPs (e.g. benzotriazole, carbamazepine) were removed by >80% up to throughputs of 8000-10,000 bed volumes (BV), whereas weakly to medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) showed removals adsorptive removal, resulting in rapid concentration

  12. Integrating organic micropollutant removal into tertiary filtration: Combining PAC adsorption with advanced phosphorus removal.

    Science.gov (United States)

    Altmann, Johannes; Sperlich, Alexander; Jekel, Martin

    2015-11-01

    Direct addition of powdered activated carbon (PAC) to a deep-bed filter was investigated at pilot-scale as a single advanced treatment stage for simultaneous removal of organic micropollutants (OMPs) and phosphorus from secondary effluent. PAC doses of 10-50 mg/L were assessed with regard to their impacts on filter performance and removal of 15 selected OMPs over a period of 18 months. The PAC was effectively retained by the filter and had no negative effect on filter head loss. Filter runtime until particle breakthrough depended mainly on coagulant dose and did not decrease significantly due to the additional PAC load. Removal of suspended solids and phosphorus by coagulation was effective independent of the PAC dose. A PAC dose of 35 mg/L PAC was suitable to remove well-adsorbing OMPs (e.g. carbamazepine, diclofenac) by >80% and medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) by 50-80%. Median removals were 50-80% for well-adsorbing and 30-50% for medium adsorbing OMPs with 20 mg/L PAC. Abatement of all OMPs was low (PAC, possibly because of the high effluent organic matter content (median dissolved organic carbon (DOC) concentrations of 11.2 mg/L). In addition to adsorptive removal, relevant concentration decreases of certain OMPs (e.g. 4-formylaminoantipyrine) were attributed to biological transformation in the filter. Adsorption onto accumulating PAC in the top layer of the filter bed led to improved OMP adsorption with increasing filter runtime. The comparison of OMP removal in the pilot filter with laboratory adsorption tests demonstrates that batch test results can be applied to estimate adsorptive OMP removal in real applications.

  13. Boron nitride ultrathin fibrous nanonets: one-step synthesis and applications for ultrafast adsorption for water treatment and selective filtration of nanoparticles.

    Science.gov (United States)

    Lian, Gang; Zhang, Xiao; Si, Haibin; Wang, Jun; Cui, Deliang; Wang, Qilong

    2013-12-26

    Novel boron nitride (BN) ultrathin fibrous networks are firstly synthesized via an one-step solvothermal process. The average diameter of BN nanofibers is only ~8 nm. This nanonets exhibit excellent performance for water treatment. The maximum adsorption capacity for methyl blue is 327.8 mg g(-1). Especially, they present the property of ultrafast adsorption for dye removal. Only ~1 min is enough to almost achieve the adsorption equilibrium. In addition, the BN fibrous nanonets could be applied for the size-selective separation of nanoparticles via a filtration process.

  14. An improved method for purification of recombinant truncated heme oxygenase-1 by expanded bed adsorption and gel filtration.

    Science.gov (United States)

    Hu, Hong-Bo; Wang, Wei; Han, Ling; Zhou, Wen-Pu; Zhang, Xue-Hong

    2007-03-01

    Recombinant truncated human heme oxygenase-1 (hHO-1) expressed in Escherichia coli was efficiently separated and purified from feedstock by DEAE-ion exchange expanded bed adsorption. Protocol optimization of hHO-1 on DEAE adsorbent resulted in adsorption in 0 M NaCl and elution in 150 mM NaCl at a pH of 8.5. The active enzyme fractions separated from the expanded bed column were further purified by a Superdex 75 gel filtration step. The specific hHO-1 activity increased from 0.82 +/- 0.05 to 24.8 +/- 1.8 U/mg during the whole purification steps. The recovery and purification factor of truncated hHO-1 of the whole purification were 72.7 +/- 4.7 and 30.2 +/- 2.3%, respectively. This purification process can decrease the demand on the preparation of feedstock and simplify the purification process.

  15. HEMOFILTRATION AND COUPLED PLASMA FILTRATION ADSORPTION IMPACT ON TACROLIMUS BLOOD CONCENTRATION IN RENAL TRANSPLANT RECIPIENTS

    Directory of Open Access Journals (Sweden)

    A.V. Vatazin

    2014-01-01

    Full Text Available Aim. To study the effect of hemofi ltration and coupled plasma fi ltration adsorption on tacrolimus blood concentration in renal transplant recipients.Methods and results. The study included 8 renal transplant recipients. In these patients immediately after the operation was performed the coupled plasma fi ltration adsorption with hemofiltration using a cartridge Mediasorb to reduce the severity of reperfusion injury. We have found that during this extracorporeal blood correction procedure there was statistically not signifi cant decrease of tacrolimus blood concentration. However, concentration of tacrolimus remained in the therapeutic range even after the procedure and it was not signifi cantly different from the control point С0.Conclusion. Coupled plasma fi ltration adsorption is safe in renal transplant recipients and has no signifi cant impact on tacrolimus blood concentration. However, the downward trend in the concentration of tacrolimus in the course of these procedures, especially in continuous or semicontinuous mode, as well as in patients with low hematocrit and hypoalbuminemia, requires individual monitoring.

  16. How can liver toxins be removed? Filtration and adsorption with the Prometheus system.

    Science.gov (United States)

    Vienken, Joerg; Christmann, Horst

    2006-04-01

    The application of extracorporeal blood circuits in liver failure therapy has its roots in the two functions of the liver, first as a detoxifying and second as a synthetizing organ. In contrast to hydrophilic uremic toxins, most liver toxins are hydrophobic and bind preferentially to blood proteins. Consequently, the majority of these compounds cannot be removed by hemodialysis or similar dialytic procedures. Current systems use albumin as a transport vehicle for hydrophobic compounds across high flux membranes (e.g. albumin-dialysis, molecular adsorbent recirculating system (MARS)). In contrast to these devices, the Prometheus system (Fresenius Medical Care, Bad Homburg, Germany) applies filtration across highly permeable membranes with a molecular weight cut-off of >300.000. These membranes facilitate a direct filtration of most of the toxin-bearing proteins. In a secondary circuit these toxins are then removed by adsorber beads assembled in specially designed cartridges. The protein-containing toxin-free solution returns to the primary circuit. Clinical testing of the Prometheus system's safety and efficacy parameters showed that cell counts and coagulation factors were not significantly affected. Total bilirubin-, bile acid- and plasma ammonia-levels were reduced in vivo by -21%, -43% and -40%, respectively. First successful therapeutic results have been obtained for patients treated for drug abuse and for patients waiting for transplantation. Thus, a combination of plasma fractionation with highly permeable membranes followed by a secondary circuit with adsorber cartridges proves to be the most effective method of removing toxic waste in liver failure. Further investigations will follow in order to extend the application of the Prometheus system to larger cohorts of patients.

  17. Coupled plasma filtration adsorption for the treatment of a patient with acute respiratory distress syndrome and acute kidney injury: a case report.

    Science.gov (United States)

    Lucisano, Gaetano; Capria, Maria; Matera, Giovanni; Presta, Pierangela; Comi, Nicolino; Talarico, Roberta; Rametti, Linda; Quirino, Angela; Giancotti, Aida; Fuiano, Giorgio

    2011-10-01

    Coupled plasma filtration adsorption (CPFA) is an extracorporeal blood purification therapy based on non-specific pro- and anti-inflammatory mediator adsorption on a special resin cartridge coupled with continuous veno-venous haemofiltration or continuous veno-venous haemodiafiltration and is one of the emerging treatments for septic patients. However, in the literature, there are limited data about its efficacy in treating patients with acute diseases but without the traditional criteria for sepsis. We describe the case of a 43-year-old male who developed acute respiratory distress syndrome secondary to pneumonia and acute kidney injury, whose clinical conditions rapidly improved after early CPFA therapy.

  18. Influence of the charge of low molecular weight proteins on their efficacy of filtration and/or adsorption on dialysis membranes with different intrinsic properties.

    Science.gov (United States)

    Moachon, N; Boullange, C; Fraud, S; Vial, E; Thomas, M; Quash, G

    2002-02-01

    Hemodialysis membranes eliminate by filtration low-molecular-weight toxic metabolites (urea and creatinine) with minimum interactions between blood components and the membrane itself. However, the ability of a membrane to adsorb specific proteins could be beneficial if the accumulation of these same proteins is implicated in the genesis of a pathological condition. Beta-amyloidosis which accompanies the elevation of beta2-microglobulin (11.8 kDa) in the plasma of dialysed patients is one such condition (Biochem. Biophys. Res. Commun. 129 (3) (1985) 701-706: Lancet 1 (1986) 1240-1311). To determine whether increases in plasma beta2-microglobulin levels were due to differences in filtration efficacy of the membrane used and/or to certain characteristics of this protein, e.g. its charge (pI 5.7) the adsorption and filtration of [3H] beta2-microglobulin and [3H] lysozyme of similar MW 14.5 kDa, but pI: 10.8 were compared on different membranes. It was found that, neither [3H] beta2-microglobulin nor [3H] lysozyme are removed by cuprophan, whereas over 75% of beta2-microglobulin is removed by filtration on polyacrylonitrile, polyacrylonitrile-polyethyleneimine, polysulfone and >95% by adsorption to polymethylmethacrylate-BK. For lysozyme, removal by adsorption is >95% on polyacrylonitrile and polyacrylonitrile-polyethyleneimine, 72% on polymethylmethacrylate-BK and by filtration is 95% on polysulfone. Hemodialysis membranes must therefore not simply be considered as filters of low-molecular-weight metabolites but should be equally assessed for their capacity to eliminate potentially deleterious low-molecular-weight plasma proteins.

  19. Adsorption of Reactive Red 2 from aqueous solutions using Fe{sub 3}O{sub 4} nanoparticles prepared by co-precipitation in a rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chia-Chang, E-mail: higee@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Lin, Yu-Shung [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Ho, Jui-Min [Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China)

    2016-05-05

    A rotating packed bed (RPB) that was operated at a rotating speed of 1800 rpm with liquid flow rates of 0.5 L/min was used to prepare Fe{sub 3}O{sub 4} nanoparticles (RPB-Fe{sub 3}O{sub 4}). The RPB-Fe{sub 3}O{sub 4} had a smaller average size and a narrower size distribution than the Fe{sub 3}O{sub 4} that was obtained from Aldrich, and so had a greater capacity to adsorb RR2. The effects of pH, Fe{sub 3}O{sub 4} dosage, initial RR2 concentration, and temperature on the adsorption of RR2 were examined experimentally using RPB-Fe{sub 3}O{sub 4}. A thermodynamic study revealed that the adsorption process was spontaneous and exothermic. The adsorption behavior was more consistent with the Langmuir model than with the Freundlich model, and the maximum adsorption capacity was 97.8 mg/g. At pH 3, 25 °C, an Fe{sub 3}O{sub 4} dosage of 0.30 g/L, and an initial RR2 concentration of 10 mg/L, RPB-Fe{sub 3}O{sub 4} effectively adsorbed RR2 with a removal efficiency of approximately 95% in 10 min. These promising results clearly reveal the potential of RPB-Fe{sub 3}O{sub 4} for use in the effective removal of dyes from aqueous solutions. - Highlights: • A novel magnetic adsorbent (Fe{sub 3}O{sub 4} nanoparticles) was prepared in RPB. • 95% removal of RR2 was achieved in 10 min using Fe{sub 3}O{sub 4} nanoparticles. • This investigation provides a novel treatment of dye-contaminated wastewater.

  20. Mainstream Smoke Gas Phase Filtration Performance of Adsorption Materials Evaluated With A Puff-by-Puff Multiplex GC-MS Method

    Directory of Open Access Journals (Sweden)

    Xue L

    2014-12-01

    Full Text Available The mainstream smoke filtration performance of activated carbon, silica gel and polymeric aromatic resins for gas-phase components was evaluated using a puff-by-puff multiplex gas chromatography-mass spectrometry (GC-MS analysis method (1. The sample 1R4F Kentucky reference cigarettes were modified by placing the adsorbents in a plug/space/plug filter configuration. Due to differences in surface area and structural characteristics, the adsorbent materials studied showed different levels of filtration activities for the twenty-six constituents monitored. Activated carbon had significant adsorption activity for all the gas-phase smoke constituents observed except ethane and carbon dioxide, while silica gel had significant activities for polar components such as aldehydes, acrolein, ketones, and diacetyl. XAD-16 polyaromatic resins showed varied levels of activity for aromatic compounds, cyclic dienes and ketones.

  1. Polymeric microspheres with N-methyl-D-glucamine ligands for boron removal from water solution by adsorption-membrane filtration process.

    Science.gov (United States)

    Wolska, Joanna; Bryjak, Marek; Kabay, Nalan

    2010-08-01

    Polymeric microspheres with N-methyl-D-glucamine (NMDG) ligands have been tested in the adsorption-membrane filtration process for boron removal from aqueous solutions. The chelating resins were synthesized by reacting NMDG with the vinylbenzyl chloride-styrene-1,4-divinylbenzene (VBC/S/DVB) copolymer at the reflux temperature and in the microwave reactor. VBC/S/DVB spheres with a gel structure that contained 6 wt% DVB were obtained by membrane emulsification followed by suspension polymerization. By selecting the optimal emulsification and polymerization parameters, it was possible to obtain 25-microm-diameter particles with a narrow size distribution. Resins obtained by microwave modification showed the higher boron adsorption capacity.

  2. Adsorptive

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    Vinod Kumar Gupta

    2017-05-01

    Full Text Available This work explores the feasibility of natural fibers derived from Ficus carica plant as an alternative precursor for the preparation of activated carbon via microwave assisted H3PO4 activation. The properties of activated carbon were investigated by scanning electron microscope (SEM and Fourier transform spectroscopy (FTIR. The operational parameters, chemical impregnation ratio, microwave power and irradiation time on the carbon yield and adsorption capability were investigated. Adsorption performance of Cu(II and Ni(II onto activated carbon was investigated as a function of pH, contact time, initial metal ion concentration and temperature. The adsorption capacity of Cu(II and Ni(II onto the adsorbent was found to be 23.08 and 18.78 mg/g, respectively. Adsorption of metal ions followed second order kinetics with best fit for Fraundlich adsorption isotherm. The values of thermodynamic parameters such as enthalpy change (ΔH°, entropy change (ΔS° and free energy change (ΔG° were evaluated for the adsorption of both the metal ions. Adsorption of metal ions onto activated carbon was spontaneous and endothermic in nature. The results suggested that activated carbon developed from natural fibers successfully improved the metal ions adsorption capacity. On the basis of our findings, the adsorbent could be used as a detoxifying agent for better management of industrial effluents.

  3. Adsorption

    Directory of Open Access Journals (Sweden)

    Denis J.L. Guerra

    2016-09-01

    Full Text Available Nontronite is an important phyllosilicate with a high concentration of ferric iron in the octahedral layer. A new occurrence of Brazilian nontronite sample was used for the organofunctionalization process with 3-aminopropyltriethoxysilane. Due to the increment of basic centers attached to the pendant chains, the metal adsorption capability of the final chelating material, was found to be higher than its precursor. The ability of these materials to remove Pb2+, Mn2+, and Zn2+ from aqueous solutions was followed by a series of adsorption isotherms at room temperature and pH 6.0, in batch adsorption experiments in order to explain the adsorption mechanism. In order to evaluate the phyllosilicate samples as adsorbents in a dynamic system, a glass column was fulfilled with nontronite samples (1.5 g and it was fed with 2.1 mmol dm−3 divalent cations at pH 6.0. The energetic effects caused by metal cations adsorption were determined through calorimetric titrations. The effects of three divalent metals adsorption in the zero point of charge of each material were investigated.

  4. Severe Hemolysis in a Patient With Erythrocytosis During Coupled Plasma Filtration Adsorption Therapy Was Prevented by Changing From Membrane-Based Technique to a Centrifuge-Based One.

    Science.gov (United States)

    Fan, Rong; Wu, Buyun; Kong, Ling; Gong, Dehua

    2016-01-01

    Coupled plasma filtration adsorption (CPFA) usually adopts membrane to separate plasma from blood. Here, we reported a case with erythrocytosis experienced severe hemolysis and membrane rupture during CPFA, which was avoided by changing from membrane-based technique to a centrifuge-based one. A 66-year-old man was to receive CPFA for severe hyperbilirubinemia (total bilirubin 922 μmol/L, direct bilirubin 638 μmol/L) caused by obstruction of biliary tract. He had erythrocytosis (hemoglobin 230 g/L, hematocrit 0.634) for years because of untreated tetralogy of Fallot. Severe hemolysis and membrane rupture occurred immediately after blood entering into the plasma separator even at a low flow rate (50 mL/min) and persisted after changing a new separator. Finally, centrifugal plasma separation technique was used for CPFA in this patient, and no hemolysis occurred. After 3 sessions of CPFA, total bilirubin level decreased to 199 μmol/L with an average decline by 35% per session. Thereafter, the patient received endoscopic biliary stent implantation, and total bilirubin level returned to nearly normal. Therefore, centrifugal-based plasma separation can also be used in CPFA and may be superior to a membrane-based one in patients with hyperviscosity.

  5. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

    Full Text Available Application of saw dust for the removal of an anionic dye, tartrazine, from aqueous solutions has been investigated. The experiments were carried out in batch mode. Effect of the parameters such as pH, initial dye concentration and temperature on the removal of the dye was studied. Equilibrium was achieved in 70 min. Maximum adsorption of dye was achieved at pH 3. Removal percent was found to be dependent on the initial concentration of dye solution, and maximum removal was found to be 97% at 1 mg/L of tartrazine. The removal increases from 71% to 97% when the initial concentration of dye solution decreases from 15 mg/L to 1 mg/L. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The (Langmuir adsorption capacity of the adsorbent is found to be 4.71 mg/g at 318 K. Kinetic modeling of the process of removal was carried out and the process of removal was found to follow a pseudo second order model and the value of rate constant for adsorption process was calculated as 2.7 × 10−3 g mg−1 min−1 at 318 K. The thermodynamic parameters such as change in free energy (ΔG°, enthalpy (ΔH° and entropy (ΔS° were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. Further, the values of ΔH° indicated the endothermic nature of the process of removal.

  6. Filtration Fundamentals.

    Science.gov (United States)

    Ward, Ken; Hunsaker, Scot

    1997-01-01

    Examines how choice of commercial swimming-pool filtration systems is driven by the project-specific needs of the pools. Also highlighted are definitions of specific terms used when discussing filtration systems. Questions that pool designers can answer to make filtration-system purchasing decisions are listed. (GR)

  7. Molecular Structures of Al/Si and Fe/Si Coprecipitates and the Implication for Selenite Removal.

    Science.gov (United States)

    Chan, Ya-Ting; Kuan, Wen-Hui; Tzou, Yu-Min; Chen, Tsan-Yao; Liu, Yu-Ting; Wang, Ming-Kuang; Teah, Heng-Yi

    2016-04-20

    Aluminum and iron oxides have been often used in the coagulation processes during water purification due to their unique surface properties toward anions. In the presence of silica, the coprecipitation of Al/Si or Fe/Si might decrease the efficiency of wastewater purification and reuse. In this study, surface properties and molecular structures of Al/Si and Fe/Si coprecipitates were characterized using spectroscopic techniques. Also, the selenite removal efficiency of Al/Si and Fe/Si coprecipitates in relation to their surface and structural properties was investigated. While dissolved silicate increased with increasing pH from Fe/Si coprecipitates, less than 7% of silicate was discernible from Al/Si samples over the range from acidic to alkaline conditions. Our spectroscopic results showed that the associations between Al and Si were relatively stronger than that between Fe and Si in coprecipitates. In Al/Si coprecipitates, core-shell structures were developed with AlO6/AlO4 domains as the shells and Si frameworks polymerized from the SiO2 as the cores. However, Si framework remained relatively unchanged upon coprecipitation with Fe hydroxides in Fe/Si samples. The Si core with Al shell structure of Al/Si coprecipitates shielded the negative charges from SiO2 and thereby resulted in a higher adsorption capacity of selenite than Fe/Si coprecipitates.

  8. Molecular Structures of Al/Si and Fe/Si Coprecipitates and the Implication for Selenite Removal

    Science.gov (United States)

    Chan, Ya-Ting; Kuan, Wen-Hui; Tzou, Yu-Min; Chen, Tsan-Yao; Liu, Yu-Ting; Wang, Ming-Kuang; Teah, Heng-Yi

    2016-04-01

    Aluminum and iron oxides have been often used in the coagulation processes during water purification due to their unique surface properties toward anions. In the presence of silica, the coprecipitation of Al/Si or Fe/Si might decrease the efficiency of wastewater purification and reuse. In this study, surface properties and molecular structures of Al/Si and Fe/Si coprecipitates were characterized using spectroscopic techniques. Also, the selenite removal efficiency of Al/Si and Fe/Si coprecipitates in relation to their surface and structural properties was investigated. While dissolved silicate increased with increasing pH from Fe/Si coprecipitates, less than 7% of silicate was discernible from Al/Si samples over the range from acidic to alkaline conditions. Our spectroscopic results showed that the associations between Al and Si were relatively stronger than that between Fe and Si in coprecipitates. In Al/Si coprecipitates, core-shell structures were developed with AlO6/AlO4 domains as the shells and Si frameworks polymerized from the SiO2 as the cores. However, Si framework remained relatively unchanged upon coprecipitation with Fe hydroxides in Fe/Si samples. The Si core with Al shell structure of Al/Si coprecipitates shielded the negative charges from SiO2 and thereby resulted in a higher adsorption capacity of selenite than Fe/Si coprecipitates.

  9. Shortening filtrations

    Institute of Scientific and Technical Information of China (English)

    ENOCHS Edgar E.

    2012-01-01

    Let C be a set of modules.We argue that there is an ordinal κ such that if a module has a filtration by modules in C,then it has a filtration of length κ by direct sums of modules in C.As an application we give another way to prove a result of Saorín and (S)(t)oví(c)ek and of (S)(t)oví(c)ek.

  10. Analytical Study of Oxalates Coprecipitation

    Directory of Open Access Journals (Sweden)

    Liana MARTA

    2003-03-01

    Full Text Available The paper deals with the establishing of the oxalates coprecipitation conditions in view of the synthesis of superconducting systems. A systematic analytical study of the oxalates precipitation conditions has been performed, for obtaining superconducting materials, in the Bi Sr-Ca-Cu-O system. For this purpose, the formulae of the precipitates solubility as a function of pH and oxalate excess were established. The possible formation of hydroxo-complexes and soluble oxalato-complexes was taken into account. A BASIC program was used for tracing the precipitation curves. The curves of the solubility versus pH for different oxalate excess have plotted for the four oxalates, using a logaritmic scale. The optimal conditions for the quantitative oxalate coprecipitation have been deduced from the diagrams. The theoretical curves were confirmed by experimental results. From the precursors obtained by this method, the BSCCO superconducting phases were obtained by an appropriate thermal treatment. The formation of the superconducting phases was identified by X-ray diffraction analysis.

  11. Effects of natural organic matter on the coprecipitation of arsenic with iron.

    Science.gov (United States)

    Kim, Eun Jung; Hwang, Bo-Ram; Baek, Kitae

    2015-12-01

    Natural organic matter (NOM) can affect arsenic speciation and mobility in the environment. In this study, the effects of NOM on the coprecipitation of arsenic with iron were investigated in order to better understand the fate and transport of arsenic in natural environments. The coprecipitation of arsenic with iron was studied in the presence and absence of NOM under various arsenic-to-iron molar ratios (As/Fe) and pH conditions. The addition of humic acid (HA) hindered the As-Fe coprecipitation under high pH and high As/Fe conditions by forming a soluble As-Fe-HA complex. The X-ray diffraction and Fourier transform infrared studies showed that the As-Fe-coprecipitated solid phase was highly affected by pH and As/Fe. The arsenic was coprecipitated with iron as an amorphous ferric arsenate phase at a low pH level or high As/Fe conditions, while the formation of ferrihydrite phase and the arsenic incorporation to the ferrihydrite by adsorption was predominant at high pH levels or low As/Fe conditions. The HA affected the As-Fe-coprecipitated solid phase depending on the As/Fe molar ratio under neutral and alkaline conditions.

  12. Influence of Reaction Time of Urea Hydrolysis-Based Co-precipitation on the Structure of ZnA! Layered Double Hydroxides and the Phosphate Adsorption%尿素分解共沉淀法中反应时间对ZnAl类水滑石结构和磷吸附性能的影响

    Institute of Scientific and Technical Information of China (English)

    陆英; 程翔; 邢波; 孙中恩; 孙德智

    2012-01-01

    A series of ZnAl layered double hydroxides(LDHs) were prepared by urea hydrolysis-based homogeneous co-precipitation for studying their structure and phosphate adsorption capacities.The results show that all the samples exhibited a typical layered structure as the reaction time extended from 12 h to 96 h,whereas Zn/Al molar ratio in the ZnAls decreased from 2.06 to 0.70 and the specific surface area markedly increased to be 7.6-fold higher than that of ZnAl-12.Phosphate adsorption capacity of the ZnAl was in general increased gradually with the reaction time extension,which can be attributed to the surface area rising as well as the increased positive charge of LDHs layer caused by a higher proportion of Al.This reveals that physicochemical adsorption on LDHs surface would have played an important role during the phosphate adsorption.With a reaction time of 24 h,a high amount of exchangeable interlayer anions was observed,giving rise to a highest phosphate uptake of 34.1 mg·g-1 by the ZnAl-24.It indicates the ion exchange was another major pathway for the phosphate removal.For all the ZnAls with different reaction times,the phosphate adsorption isotherms fit well with Langmuir-type equations;the adsorption kinetics followed pseudo-second-order models.%采用尿素分解均匀共沉淀法合成了一系列反应时间不同的ZnAl类水滑石,考察了其结构特征及其对水中磷酸根的吸附性能.结果表明,随着反应时间由12 h增加至96 h,制得的ZnAl均具有典型的类水滑石层状结构,但其中的n(Zn)/n(Al)由2.06降至0.70,比表面积升至ZnAl-12的7.6倍.样品中Al比例升高引起的层板正电性增加以及样品比表面积的升高引起了ZnAl对水中磷酸根的吸附性能总体上随着其制备反应时间的增加逐渐增强,同时表明表面的物理化学吸附在磷酸根的去除过程中具有重要作用.当反应时间为24 h时,制备得到的ZnAl类水滑石由于其很高的可交换阴离子

  13. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devices The Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  14. Effect of preparation conditions on physicochemical, surface and catalytic properties of cobalt ferrite prepared by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    El-Shobaky, G.A., E-mail: elshobaky@yahoo.co [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt); Turky, A.M.; Mostafa, N.Y.; Mohamed, S.K. [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

    2010-03-18

    Cobalt ferrite nanoparticles were prepared via thermal treatment of cobalt-iron mixed hydroxides at 400-600 {sup o}C. The mixed hydroxides were coprecipitated from their nitrates solutions using NaOH as precipitating agent. The effects of pH and temperature of coprecipitation and calcination temperature on the physicochemical, surface and catalytic properties of the prepared ferrites were studied. The prepared systems were characterized using TG, DTG, DTA, chemical analysis, atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) as well as surface and texture properties based on nitrogen adsorption-desorption isotherms. The prepared cobalt ferrites were found to be mesoporous materials that have crystallite size ranges between 8 and 45 nm. The surface and catalytic properties of the produced ferrite phase were strongly dependent on coprecipitation conditions of the mixed hydroxides and on their calcination temperature.

  15. Hexaferrite particles by coprecipitation and lyophilization

    Science.gov (United States)

    Calleja, A.; Tijero, E.; Martínez, B.; Piñol, S.; Sandiumenge, F.; Obradors, X.

    1999-05-01

    Fine strontium hexaferrite particles were prepared by lyophilization (known as freeze-drying) and coprecipitation of nitrates and chloride salts, respectively. The resulting powders were calcined at different temperatures between 700°C and 1100°C. As concluded from the measured hysteresis loops at 300 K, the freeze-dried hexaferrite showed good magnetic characteristics, the coercivity being as high as 5690 Oe. However, coprecipitated hexaferrite displayed poor coercivity values, around 1300 Oe at best.

  16. Synthetic coprecipitates of exopolysaccharides and ferrihydrite. Part II: Siderophore-promoted dissolution

    Science.gov (United States)

    Mikutta, Christian; Kretzschmar, Ruben

    2008-02-01

    Ferrihydrite (Fh) coprecipitated with exopolymers of plants and microbes may differ in its geochemical reactivity from its abiotic counterpart. We synthesized Fh in the presence and absence of acid polysaccharides (polygalacturonic acid (PGA), alginate, xanthan) and characterized the physical and structural properties of the precipitates formed [Mikutta C., Mikutta R., Bonneville S., Wagner F., Voegelin A., Christl I. and Kretzschmar R. (2008) Synthetic coprecipitates of exopolysaccharides and ferrihydrite. Part I: Characterization. Geochim. Cosmochim. Acta]. In this paper, we focus on the reactivity of PGA and alginate coprecipitates and pure Fh, and studied their interaction with the microbial siderophore desferrioxamine B (DFOB) in the presence and absence of low molecular weight organic (LMWO) acid anions (malate, citrate). Batch adsorption and dissolution experiments were performed in the dark at pH 7 in 10 mM NaClO 4 background electrolyte. In the dissolution experiments, different modes of ligand addition were applied (single, simultaneous, stepwise). With an estimated Langmuir sorption maximum of 15 mmol/mol Fe, a PGA coprecipitate with 11% C org sorbed about four times as much DFOB as pure Fh, and the amount of DFOB sorbed was ˜4-fold larger than estimated from the sum of DFOB sorption to pure Fh and PGA alone. The apparent initial dissolution rates, Rapp-initial, and pseudo-first order rate coefficients, k, of the coprecipitates exceeded those of pure Fh by up to two orders of magnitude. Citrate and malate exerted a strong synergistic effect on the DFOB-promoted dissolution of pure Fh, whereas synergistic effects of both anions were absent or negligible for the coprecipitates. Rapp-initial of the citrate and DFOB-promoted dissolution of PGA coprecipitates increased with increasing molar C/Fe ratio of the coprecipitates, independent of the charge of the LMWO ligand. Our results indicate that polyuronates stabilize Fh particles sterically and /or

  17. Modus of filtration.

    Science.gov (United States)

    Meltzer, Theodore H

    2006-01-01

    Experience teaches that particles larger than the pores of a filter cannot negotiate its passage. Other retention mechanisms are less obvious than sieve retention or size exclusion. They are electrical in nature, and find expression in the bonding alliances that mutually attract (or repel) filters and particles. The influence of hydrogen bonds, of van der Waals forces, of hydrophobic adsorptions, and of transient polarities on particle retentions are set forth in terms of the double electrical layer concept that also governs colloidal destabilizations. The origins of differences in membrane porosities is explained, as also the importance of the filtration conditions. The singularity of the particle-fluid-filter relationship on organism and/or pore size alteration is stressed.

  18. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devicesThe Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  19. Removal of borate by coprecipitation with Mg/Al layered double hydroxide

    Science.gov (United States)

    Kurashina, Masashi; Inoue, Tatsuki; Tajima, Chihiro; Kanezaki, Eiji

    2015-03-01

    Borate has been used for various industrial products and excessive dose of boron is harmful to humans. We investigated the removal of borate by direct coprecipitation with Mg/Al layered double hydroxide. In this study, the maximum removal of boron was 90% when Mg 30 mmol and Al 15 mmol at pH = 10 were used for 498 mg/l as B. The boron adsorption isotherms could be fitted to Langmuir model. The calculated constant Ws, saturation limit of boron adsorption, is 25 ± 2 mg/g and it is larger than that of ion exchange reaction (Ws = 15±1 mg/g).

  20. Coprecipitation of radon oxide with cesium fluoroxenate

    Energy Technology Data Exchange (ETDEWEB)

    Avrorin, V.V.; Krasikova, R.N.; Nefedov, V.D.; Toropova, M.A.

    1986-03-01

    This paper presents a study of the processes of coprecipitation of radon oxide with cesium fluoroxenate in aqueous solutions. It has been shown that the reason for the coprecipitation in the case at hand is the occurrence of a process of isomorphous cocrystallization. The results obtained are examined as a confirmation of the suggestion that the hydrolysis product of the radon fluoride which is formed on thermal initiation of reaction in the rn-F2-BrF5-NaF system is radon trioxide, Rno3.

  1. COMBINED PLASMA FILTRATION, SELECTIVE ADSORPTION OF CYTOKINES WITH HEMOFILTRATION AND PLASMA EXCHANGE IN THE CORRECTION OF PLATELET AND COAGULATION HEMOSTASIS IN PATIENTS WITH THE SYNDROME OF DISSEMINATED INTRAVASCULAR COAGULATION

    Directory of Open Access Journals (Sweden)

    L. V. Belskikh

    2015-01-01

    value or continued to increase progressively. In this subgroup of the patients purulent complications progressed in 9 patients, mortality was 35%. Conclusion. Thus, the level of thrombocyte hemostasis in different phases of pancreatic necrosis can be quantified using indicators of morphofunctional status of circulating platelets. When dealing with coagulation version of disseminated intravascular coagulation syndrome the number of activated cells is on the rise up to 40% or more. The development of consumption coagulopathy is characterized with progressive increase of degenerative platelets up to 10% or more. Combined plasma filtration, selective adsorption of cytokines with hemofiltration and exchange plasmapheresis are effective methods for adjusting of platelet and coagulation hemostasis in patients with necrotizing pancreatitis.

  2. Experimental and modeling studies of coprecipitation as an attenuation mechanism for radionuclides, metals, and metalloid mobility

    Science.gov (United States)

    Zhu, C.; Martin, S.; Ford, R.; Nuhfer, N.

    2003-04-01

    Coprecipitation (CPT) is typically defined as the simultaneous removal of both the tracer and carrier constituents from an aqueous solution without regard to the specific mechanisms involved. CPT is potentially important to many environmental issues closely related to water resources, including acid mine drainage, radionuclide migration in fouled waste repositories, metal contaminant transport at industrial and defense sites, metal concentrations in aquatic systems, and wastewater treatment technology. The coprecipitation process may vary in each case and solid phase partitioning may be driven by surface adsorption, ion-exchange, surface precipitation, occlusion, and solid solution formation. Solid solution formation is a result of structural incorporation of the tracer into carrier structural sites resulting in a minor constituent in solid solution with the host phase possessing a solubility greatly reduced from that of its pure solid. Coprecipitation of Pb, Zn, Al, and As with ferric iron oxides has been or is being conducted in the laboratory. The coprecipitates have been examined by High Resolution Analytical Transmission Electron Microscopy, while the bulk solution results are modeled as surface complexation, bulk precipitation, or amorphous solid solutions. Coprecipitation with iron oxides may be relevant to a fouled repository where steel containers corrode and transform into iron oxides. Additionally, the coprecipitation of radium with barite, which has relevance to both naturally occurring radioactive materials (NORM) associated with oil and gas production and nuclear waste repositories, is assessed and modeled. A general correlation is found among excess thermodynamic properties of binary solutions in the barite isostructural family, the volume mismatch between the two end-members, and the differences in the non-solvation contribution to the Gibbs free energy of formation of the substituting aqueous metal ions.

  3. Organic micropollutant removal during river bank filtration

    NARCIS (Netherlands)

    Bertelkamp, C.

    2015-01-01

    This study investigated the factors influencing the main removal mechanisms (adsorption and biodegradation) for organic micropollutant (OMP) removal during river bank filtration (RBF) and the possibility of developing a predictive model of this process for OMP removal during RBF. Chapter 2 analysed

  4. Evaluation of Filtration and UV Disinfection for Inactivation of Viruses in Non-Community Water Systems in Minnesota

    Science.gov (United States)

    This study evaluated filtration and disinfection processes for removal and inactivation of pathogens in non-community water systems (NCWS) in two surface water supplies. Pretreatment systems included 1) pressure sand filtration, and 2) granular activated carbon adsorption, and 3...

  5. Glomerular filtration rate

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007305.htm Glomerular filtration rate To use the sharing features on this page, please enable JavaScript. Glomerular filtration rate (GFR) is a test used to check ...

  6. Rotary filtration system

    Science.gov (United States)

    Herman, David T.; Maxwell, David N.

    2011-04-19

    A rotary filtration apparatus for filtering a feed fluid into permeate is provided. The rotary filtration apparatus includes a container that has a feed fluid inlet. A shaft is at least partially disposed in the container and has a passageway for the transport of permeate. A disk stack made of a plurality of filtration disks is mounted onto the shaft so that rotation of the shaft causes rotation of the filtration disks. The filtration disks may be made of steel components and may be welded together. The shaft may penetrate a filtering section of the container at a single location. The rotary filtration apparatus may also incorporate a bellows seal to prevent leakage along the shaft, and an around the shaft union rotary joint to allow for removal of permeate. Various components of the rotary filtration apparatus may be removed as a single assembly.

  7. Role of Fe(II) and phosphate in arsenic uptake by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, N.; Lee, Y.J.; Xu, H.; Ciardelli, M.; Gaillard, J.-F. (NWU); (UW)

    2008-07-08

    Natural attenuation of arsenic by simple adsorption on oxyhydroxides may be limited due to competing oxyanions, but uptake by coprecipitation may locally sequester arsenic. We have systematically investigated the mechanism and mode (adsorption versus coprecipitation) of arsenic uptake in the presence of carbonate and phosphate, from solutions of inorganic composition similar to many groundwaters. Efficient arsenic removal, >95% As(V) and {approx}55% in initial As(III) systems, occurred over 24 h at pHs 5.5-6.5 when Fe(II) and hydroxylapatite (Ca{sub 5}(PO{sub 4}){sub 3}OH, HAP) 'seed' crystals were added to solutions that had been previously reacted with HAP, atmospheric CO{sub 2(g)} and O{sub 2(g)}. Arsenic adsorption was insignificant (<10%) on HAP without Fe(II). Greater uptake in the As(III) system in the presence of Fe(II) was interpreted as due to faster As(III) to As(V) oxidation by molecular oxygen in a putative pathway involving Fe(IV) and As(IV) intermediate species. HAP acts as a pH buffer that allows faster Fe(II) oxidation. Solution analyses coupled with high-resolution transmission electron microscopy (HRTEM), X-ray Energy-Dispersive Spectroscopy (EDS), and X-Ray Absorption Spectroscopy (XAS) indicated the precipitation of sub-spherical particles of an amorphous, chemically-mixed, nanophase, Fe{sup III}[(OH){sub 3}(PO{sub 4})(As{sup V}O{sub 4})] {center_dot} nH{sub 2}O or Fe{sup III}[(OH){sub 3}(PO{sub 4})(As{sup V}O{sub 4})(As{sup III}O{sub 3}){sub minor}] {center_dot} nH{sub 2}O, where As{sup III}O{sub 3} is a minor component. The mode of As uptake was further investigated in binary coprecipitation (Fe(II) + As(III) or P), and ternary coprecipitation and adsorption experiments (Fe(II) + As(III) + P) at variable As/Fe, P/Fe and As/P/Fe ratios. Foil-like, poorly crystalline, nanoparticles of Fe{sup III}(OH){sub 3} and sub-spherical, amorphous, chemically-mixed, metastable nanoparticles of Fe{sup III}[(OH){sub 3}, PO{sub 4}] {center_dot} n

  8. Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

    Directory of Open Access Journals (Sweden)

    Rodrigo Alarcón

    2014-07-01

    Full Text Available Sea level rise is able to change the geochemical conditions in coastal systems. In these environments, transport of contaminants can be controlled by the stability and adsorption capacity of iron oxides. The behavior of adsorbed and co-precipitated arsenic in jarosite, schwertmannite, ferrihydrite, and goethite in sea water (common secondary minerals in coastal tailings was investigated. The aim of the investigation was to establish As retention and transport under a marine flood scenario, which may occur due to climate change. Natural and synthetic minerals with co-precipitated and adsorbed As were contacted with seawater for 25 days. During this period As, Fe, Cl, SO4, and pH levels were constantly measured. The larger retention capability of samples with co-precipitated As, in relation with adsorbed As samples, reflects the different kinetics between diffusion, dissolution, and surface exchange processes. Ferrihydrite and schwertmannite showed good results in retaining arsenic, although schwertmannite holding capacity was enhanced due its buffering capacity, which prevented reductive dissolution throughout the experiment. Arsenic desorption from goethite could be understood in terms of ion exchange between oxides and electrolytes, due to the charge difference generated by a low point-of-zero-charge and the change in stability of surface complexes between synthesis conditions and natural media.

  9. Sequestration of uranium on fabricated aluminum co-precipitated with goethite (Al-FeOOH)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yubing; Yang, Shubin; Wang, Qi; Wang, Xiangke [Chinese Academy of Science, Hefei (China). Key Laboratory of Novel Thin Film Solar Cells; Alsaedi, Ahmad [King Abdulaziz Univ., Jeddah (Saudi Arabia). Nonlinear Analysis and Applied Mathematics (NAAM) Research Group

    2014-11-01

    Aluminum co-precipitated with goethites (Al-FeOOHs) are ubiquitous within (sub)-surface environments, which are considered one of the most important sinks for radionuclide pollution management. Accordingly, various mole ratios Al-FeOOH were synthesized and characterized by XRD, FT-IR, TEM, specific surface area and potentiometric acid-base titration. According to XRD and TEM images, the morphology of Al-FeOOH was transformed from acicular-like goethite to cotton-like gibbsite with increasing Al content. The adsorption and sequential desorption of U(VI) on Al-FeOOHs were conducted by batch techniques under N{sub 2} conditions. The batch adsorption results showed that the adsorption of U(VI) on Al-FeOOHs slightly increased at pH < 4.0, then the significant increase of U(VI) adsorption was observed at pH from 4.0 to 7.0, whereas the suppressed adsorption at pH > 8.0 was due to the electrostatic repulsion between negative charge surface and negative carbonato-complexes. The adsorption of U(VI) on Al-FeOOHs was independent of ionic strength at pH > 5.0, indicating that the inner-sphere surface complexation predominated their adsorption behaviors, whereas U(VI) adsorption on Al-FeOOH could be the outer-sphere surface/cation exchange reaction. The sequential extraction texts showed that the desorption of U(VI) from Al-FeOOHs decreased with increasing Al content. These findings highlighted the effect of Al content on the sequestration and immobilization of U(VI) onto Al-FeOOHs from (sub)-surface environments in pollution management.

  10. Evaluation of Co-precipitation Processes for the Synthesis of Mixed-Oxide Fuel Feedstock Materials

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Emory D [ORNL; Voit, Stewart L [ORNL; Vedder, Raymond James [ORNL

    2011-06-01

    controlled for co-precipitation processes include (1) feed solution concentration adjustment, (2) precipitant concentration and addition methods, (3) pH, temperature, mixing method and time, (4) valence adjustment, (5) solid precipitate separation from the filtrate 'mother liquor,' generally by means of centrifugation or filtration, and (6) temperatures and times for drying, calcination, and reduction of the MOX product powder. Also a recovery step is necessary because of low, but finite solubility of the U/TRU metals in the mother liquor. The recovery step usually involves destruction of the residual precipitant and disposal of by-product wastes. Direct denitrations of U/TRU require fewer steps, but must utilize various methods to enable production of MOX with product characteristics that are acceptable for recycle fuel fabrication. The three co-precipitation processes considered for evaluation are (1) the ammonia co-precipitation process being developed in Russia, (2) the oxalate co-precipitation process, being developed in France, and (3) the ammonium-uranyl-plutonyl-carbonate (AUPuC) process being developed in Germany. Two direct denitration processes are presented for comparison: (1) the 'Microwave Heating (MH)' automated multi-batch process developed in Japan and (2) the 'Modified Direct Denitration (MDD)' continuous process being developed in the USA. Brief comparative descriptions of the U/TRU co-conversion processes are described. More complete details are provided in the references.

  11. Coprecipitation of radionuclides: basic concepts, literature review and first applications

    Energy Technology Data Exchange (ETDEWEB)

    Curti, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-11-01

    Coprecipitation of radionuclides with solid products is currently not analysed quantitatively in safety assessments for nuclear waste repositories, although this process is thought to be an important mechanism for limiting nuclide concentrations in solution. This is due to the fact that neither the solid phases controlling coprecipitation nor the parameter values necessary to describe this process are known sufficiently. This introductory report provides basic knowledge on this subject and a review of experimental data from the literature. Emphasis is placed on experiments of trace metal coprecipitation with calcite, because this mineral is a dominating alteration product of cement in the Swiss L/ILW repository. This resulted in a database of partition coefficients, which allow to describe empirically the distribution of trace elements between calcite and solution and thus to quantify coprecipitation processes. Since laboratory data on coprecipitation with calcite are lacking for many safety-relevant radioelements, their partition coefficients were inferred with the help of estimation techniques. Such techniques rely on empirical correlations, which relate the uptake of trace metals in calcite (measured in laboratory tests) with selected chemical properties of the coprecipitated metals (e.g. ionic radius, sorption properties, solubility products of the pure trace metal carbonates). The combination of these correlations with independent geochemical evidence allows the extrapolation of radioelement-specific partition coefficients, which are then used for the quantitative modelling. In a first step the potential role of radionuclide coprecipitation during cement degradation in the L/ILW repository planned at Wellenberg is assessed. (author) figs., tabs., refs.

  12. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    Ying, T.Y.; Chin, C.J.; Lu, S.C.; Yiacoumi, S. [Georgia Institute of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering] [and others

    1997-10-01

    Magnetic-seeding filtration consists of two steps: heterogeneous particle flocculation of magnetic and nonmagnetic particles in a stirred tank and high-gradient magnetic filtration (HGMF). The effects of various parameters affecting magnetic-seeding filtration (HGMF). The effects of various parameters affecting magnetic seeding filtration are theoretically and experimentally investigated. A trajectory model that includes hydrodynamic resistance, van der Waals, and electrostatic forces is developed to calculate the flocculation frequency in a turbulent-shear regime. Fractal dimension is introduced to simulate the open structure of aggregates. A magnetic-filtration model that consists of trajectory analysis, a particle build-up model, a breakthrough model, and a bivariate population-balance model is developed to predict the breakthrough curve of magnetic-seeding filtration. A good agreement between modeling results and experimental data is obtained. The results show that the model developed in this study can be used to predict the performance of magnetic-seeding filtration without using empirical coefficients or fitting parameters. 35 refs., 7 figs., 1 tab.

  13. Filtration in Porous Media

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    There is a considerable and ongoing effort aimed at understanding the transport and the deposition of suspended particles in porous media, especially non-Fickian transport and non-exponential deposition of particles. In this work, the influential parameters in filtration models are studied...... to understand their effects on the non-Fickian transport and the non-exponential deposition. The filtration models are validated by the comparisons between the modelling results and the experimental data.The elliptic equation with distributed filtration coefficients may be applied to model non-Fickian transport...... and hyperexponential deposition. The filtration model accounting for the migration of surface associated particles may be applied for non-monotonic deposition....

  14. Zirconium/PVA modified flat-sheet PVDF membrane as a cost-effective adsorptive and filtration material: A case study on decontamination of organic arsenic in aqueous solutions.

    Science.gov (United States)

    Zhao, Dandan; Yu, Yang; Wang, Chenghong; Chen, J Paul

    2016-09-01

    Organic arsenic in waters has been a global concern in drinking water due to its higher toxicity to humans. In this study, a novel zirconium/polyvinyl alcohol (PVA) modified polyvinylidene fluoride (PVDF) membrane was applied to remove organic arsenic from water. The impregnation of zirconium ions within the modified membrane was attributed to the coordination reactions among the zirconium ions, ether and hydroxyl groups. The synthesized membrane worked better at the acidic conditions and achieved the optimal uptake for both monomethylarsonic (MMA) and dimethylarsinic (DMA) at pH 2.0. The adsorption isotherm study demonstrated that the adsorption of both organic arsenic species was controlled by the mono-layer adsorption process; the maximum adsorption capacities for MMA and DMA were 73.04 and 37.53mg/g at pH 2, and 29.78 and 19.03mg/g at pH 7.0, respectively. The presence of humic acid had a negligible impact on the uptake of organic arsenic, whereas varying impacts on the arsenic adsorption were observed due to the presence of coexisting anions such as fluoride, phosphate, carbonate and silicate. A single piece of membrane with a surface area of only 12.56cm(2) could treat 7.5-L MMA and 4.1-L DMA solution with an influent concentration of about 100μg/L to meet the WHO and USEPA standard of 10μg/L. Based on the XPS analyses, the ion exchange reaction between chloride ions on the membrane surface and organic arsenic species was responsible for the removal of both MMA and DMA. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Water Filtration Products

    Science.gov (United States)

    1986-01-01

    American Water Corporation manufactures water filtration products which incorporate technology originally developed for manned space operations. The formula involves granular activated charcoal and other ingredients, and removes substances by catalytic reactions, mechanical filtration, and absorption. Details are proprietary. A NASA literature search contributed to development of the compound. The technology is being extended to a deodorizing compound called Biofresh which traps gas and moisture inside the unit. Further applications are anticipated.

  16. Visualization of water flow during filtration using flat filtration materials

    Directory of Open Access Journals (Sweden)

    Hrůza Jakub

    2012-04-01

    Full Text Available Filtration materials are very important elements of some industrial appliances. Water filtration is a separation of solid materials from fluid. Solid particles are captured on the frontal area of the filtration textile and only liquid passes through it. It is important to know the filtration process in a detailed way to be able to develop filtration materials. Visualization of filtration process enables a better view of the filtration. This method also enables to determine efficiency and homogeneity of filtration using image analysis. For this purpose, a new waterfiltration measuring setup was proposed and constructed. Filtration material is mounted into the optically transparent place in the setup. Laser sheet is directed into this place as in the case of Particle Image Velocimetry measuring method. Monochrome and sensitive camera records the light scattered by seeding particles in water. The seeding particles passing through the filter serve for measuring filtration efficiency, and also for visualization of filtration process. Filtration setup enables to measure also the pressure drop and a flow. The signals are processed by National Instruments compactDAQ system and UMA software. Microfibrous and nanofibrous filtration materials are tested by this measuring method. In the case of nanofibrous filtration, appropriate size of seeding particles is needed to be used to perform a process of filtration.

  17. Co-precipitation of dissolved organic matter by calcium carbonate in Pyramid Lake, Nevada

    Science.gov (United States)

    Leenheer, Jerry A.; Reddy, Michael M.

    2008-01-01

    Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals and in the lake water of Pyramid Lake, Nevada, USA. A 400-gram block of precipitated calcium carbonate from the Pyramid Lake shore was dissolved in 8 liters of 10% acetic acid. Particulate matter not dissolved by acetic acid was removed by centrifugation. DOM from the carbonate rock was fractionated into nine portions using evaporation, dialysis, resin adsorption, and selective precipitations to remove acetic acid and inorganic constituents. The calcium carbonate rock contained 0.23% DOM by weight. This DOM was enriched in polycarboxylic proteinaceous acids and hydroxy-acids in comparison with the present lake water. DOM in lake water was composed of aliphatic, alicyclic polycarboxylic acids. These compound classes were found in previous studies to inhibit calcium carbonate precipitation. DOM fractions from the carbonate rock were 14C-age dated at about 3,100 to 3,500 years before present. The mechanism of DOM co-precipitation and/or physical incorporation in the calcium carbonate is believed to be due to formation of insoluble calcium complexes with polycarboxylic proteinaceous acids and hydroxy-acids that have moderately large stability constants at the alkaline pH of the lake. DOM co-precipitation with calcium carbonate and incorporation in precipitated carbonate minerals removes proteinaceous DOM, but nearly equivalent concentrations of neutral and acidic forms of organic nitrogen in DOM remain in solution. Calcium carbonate precipitation during lime softening pretreatment of drinking water may have practical applications for removal of proteinaceous disinfection by-product precursors.

  18. Microfluidic colloid filtration

    Science.gov (United States)

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  19. CENTRIFUGAL MEMBRANE FILTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Daniel J. Stepan; Bradley G. Stevens; Melanie D. Hetland

    1999-10-01

    The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc).

  20. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    Depaoli, D. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes.

  1. Filtration by eyelashes

    Science.gov (United States)

    Vistarakula, Krishna; Bergin, Mike; Hu, David

    2010-11-01

    Nearly every mammalian and avian eye is rimmed with lashes. We investigate experimentally the ability of lashes to reduce airborne particle deposition in the eye. We hypothesize that there is an optimum eyelash length that maximizes both filtration ability and extent of peripheral vision. This hypothesis is tested using a dual approach. Using preserved heads from 36 species of animals at the American Museum of Natural History, we determine the relationship between eye size and eyelash geometry (length and spacing). We test the filtration efficacy of these geometries by deploying outdoor manikins and measuring particle deposition rate as a function of eyelash length.

  2. Kinetics and mechanism of dye adsorption on WO3 nanoparticles

    Science.gov (United States)

    Adhikari, Sangeeta; Mandal, Sandip; Sarkar, Debasish; Kim, Do-Heyoung; Madras, Giridhar

    2017-10-01

    Monoclinic WO3 nanoparticles were synthesized by a simple acid catalyzed co-precipitation reaction. Spherical particles with average size ∼55 nm were confirmed from electron microscopy followed by functional, structural and optical characterizations. The adsorption of methylene blue was examined by using WO3 nanoparticles and the capacity was higher than most of the reported studies. The effect of pH and material loading on adsorption was determined. The mechanism of adsorption was examined by XPS and a detailed explanation of surface phenomena was proposed. Regeneration study was carried and a high stability of heat treated WO3 towards adsorption of methylene blue was observed.

  3. Enlargements of filtrations and applications

    CERN Document Server

    Corcuera, J M

    2012-01-01

    In this paper we review some old and new results about the enlargement of filtrations problem, as well as their applications to credit risk and insider trading problems. The enlargement of filtrations problem consists in the study of conditions under which a semimartingale remains a semimartingale when the filtration is enlarged, and, in such a case, how to find the Doob-Meyer decomposition. Filtrations may be enlarged in different ways. In this paper we consider initial and progressive filtration enlargements made by random variables and processes. Keywords: Credit Risk, Insider Trading, Enlargement of Filtrations

  4. Water Treatment Technology - Filtration.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

  5. Supercritical antisolvent co-precipitation of rifampicin and ethyl cellulose

    CSIR Research Space (South Africa)

    Djerafi, R

    2017-05-01

    Full Text Available crystallinity of the active ingredient was observed and a simultaneous precipitation of ethyl cellulose and drug was achieved. The effect of solvent/CO 2 molar ratio and polymer/drug mass ratio on the co-precipitates morphology and drug loading was investigated...

  6. Treatment of arsenic-contaminated water using akaganeite adsorption

    Science.gov (United States)

    Cadena C., Fernando; Johnson, Michael D.

    2008-01-01

    The present invention comprises a method and composition using akaganeite, an iron oxide, as an ion adsorption medium for the removal of arsenic from water and affixing it onto carrier media so that it can be used in filtration systems.

  7. ADSORPTION OF Pb(II) IONS FROM AQUEOUS SOLUTION USING ...

    African Journals Online (AJOL)

    industries, tanneries, batteries and paper industries [9-12]. ... oxidation [19], membrane filtration technologies [20], biological treatment [21, 22], ... various wastewater treatment techniques described, adsorption has become one of the ...

  8. Dynamic optical filtration

    Science.gov (United States)

    Chretien, Jean-Loup (Inventor); Lu, Edward T. (Inventor)

    2005-01-01

    A dynamic optical filtration system and method effectively blocks bright light sources without impairing view of the remainder of the scene. A sensor measures light intensity and position so that selected cells of a shading matrix may interrupt the view of the bright light source by a receptor. A beamsplitter may be used so that the sensor may be located away from the receptor. The shading matrix may also be replaced by a digital micromirror device, which selectively sends image data to the receptor.

  9. Magnetic flocculation and filtration

    Energy Technology Data Exchange (ETDEWEB)

    Yiacoumi, Sotira; Chin, Ching-Ju; Yin, Tung-Yu [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering; Tsouris, C., DePaoli, D.W.; Chattin, M.R.; Spurrier, M. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    A model is available in predicting flocculation frequencies between particles of various properties under the influence of a magnetic field. This model provides a basic understanding of fundamental phenomena, such as particle-particle and particle-collector interactions, occurring in HGMF (high gradient magnetic field), and will be extended to describe experimental data of particle flocculation and filtration and predict the performance of high- gradient magnetic filters. It is also expected that this model will eventually lead to a tool for design and optimization of magnetic filters for environmental, metallurgical, biochemical, and other applications.

  10. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A. [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  11. A biological oil adsorption filter.

    Science.gov (United States)

    Pasila, Antti

    2004-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore.

  12. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    DePaoli, D.W.; Tsouris, C. [Oak Ridge National Lab., TN (United States); Yiacoumi, Sotira

    1997-10-01

    Magnetic-seeding filtration is a technology under development for the enhanced removal of magnetic and non-magnetic particulates from liquids. This process involves the addition of a small amount of magnetic seed particles (such as naturally occurring iron oxide) to a waste suspension, followed by treatment with a magnetic filter. Non-magnetic and weakly magnetic particles are made to undergo nonhomogeneous flocculation with the seed particles, forming flocs of high magnetic susceptibility that are readily removed by a conventional high-gradient magnetic filter. This technology is applicable to a wide range of liquid wastes, including groundwater, process waters, and tank supernatants. Magnetic-seeding filtration may be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes. Waste stream characteristics for which the technology may be applicable include (1) particle sizes ranging from relatively coarse (several microns) to colloidal particles, (2) high or low radiation levels, (3) broad-ranging flow rates, (4) low to moderate solids concentration, (5) cases requiring high decontamination factors, and (6) aqueous or non-aqueous liquids. At this point, the technology is at the bench-scale stage of development; laboratory studies and fundamental modeling are currently being employed to determine the capabilities of the process.

  13. Perlite filtration of phenolic compounds from cigarette smoke.

    Science.gov (United States)

    Rostami-Charati, Faramarz; Robati, Gholamreza Moradi; Naghizadeh, Farhad; Hosseini, Shahnaz; Chaichi, Mohammad Javad

    2013-01-01

    Adsorption of phenolic compounds and chemical analysis of them from a local production cigarette (named by Farvardin cigarette) smoke have been investigated by using perlite filtration. In this research, the mainstream smoke was tested by three filtration methods: Perlite filter, Cambridge filter and general cigarette filter. Then the used filter was extracted by pure methanol as solvent. After that, the extracted solution was analysed by GC-MS. By this consideration, the phenolic derivatives such as phenol, hydroquinone, resorcinol, pyrocatechol, m-cresol, p-cresol and o-cresol were detected. The structure of the perlite filtration after absorption was studied by SEM. In addition, its chemical structure was investigated by XRD and XRF.

  14. Adsorption of amylase enzyme on ultrafiltration membranes.

    Science.gov (United States)

    Beier, Søren Prip; Enevoldsen, Ann Dorrit; Kontogeorgis, Georgios M; Hansen, Ernst B; Jonsson, Gunnar

    2007-08-28

    A method to measure the static adsorption on membrane surfaces has been developed and described. The static adsorption of amylase-F has been measured on two different ultrafiltration membranes, both with a cutoff value of 10 kDa (a PES membrane and the ETNA10PP membrane, which is a surface-modified PVDF membrane). The adsorption follows the Langmuir adsorption theory. Thus, the static adsorption consists of monolayer coverage and is expressed both as a permeability drop and an adsorption resistance. From the adsorption isotherms, the maximum static permeability drops and the maximum static adsorption resistances are determined. The maximum static permeability drop for the hydrophobic PES membrane is 75%, and the maximum static adsorption resistance is 0.014 m2.h.bar/L. The maximum static permeability drop for the hydrophilic surface-modified PVDF membrane (ETNA10PP) is 23%, and the maximum static adsorption resistance is 0.0046 m2.h.bar/L. The difference in maximum static adsorption, by a factor of around 3, affects the performance during the filtration of a 5 g/L amylase-F solution at 2 bar. The two membranes behave very similarly during filtration with almost equal fluxes and retentions even though the initial water permeability of the PES membrane is around 3 times larger than the initial water permeability of the ETNA10PP membrane. This is mainly attributed to the larger maximum static adsorption of the PES membrane. The permeability drop during filtration exceeds the maximum static permeability drop, indicating that the buildup layer on the membranes during filtration exceeds monolayer coverage, which is also seen by the increase in fouling resistance during filtration. The accumulated layer on the membrane surface can be described as a continually increasing cake-layer thickness, which is independent of the membrane type. At higher concentrations of enzyme, concentration polarization effects cannot be neglected. Therefore, stagnant film theory and the osmotic

  15. Hydrous iron oxide modified diatomite as an active filtration medium for phosphate capture.

    Science.gov (United States)

    Wang, Zhe; Lin, Yan; Wu, Deyi; Kong, Hainan

    2016-02-01

    A simple method to functionalize diatomite with hydrous iron oxide was attempted and its performance as a new active filtration material to remove and recover phosphate from water was investigated under varying solution conditions. The Langmuir phosphate adsorption capacity increased from 0.6 mgP/g for raw diatomite to 4.89, 14.71, 25.02 mgP/g for hydrous iron oxide modified diatomite (HIOMD), depending on the amount of iron loaded. Loading of hydrous iron oxide caused the increase in true and bulk density and a decline in filtration rate, but to a lesser extent. It was shown that the HIOMD product with suitable iron content could retain a good filtration performance with a greatly increased adsorption capacity for phosphate. The phosphate adsorption increased by decreasing pH and by increasing ionic strength at high pH levels. The adsorption process was interpreted by ligand exchange. Coexisting oxyanions of sulfate, nitrate, citrate, carbonate, silicate and humic acid showed different effects on phosphate fixation but it was presumed that their influence at their concentrations and pH levels commonly encountered in effluent or natural waters was limited, i.e., HIOMD had a reasonably good selectivity. Results in repeated adsorption, desorption and regeneration experiment showed that the adsorbed phosphate could be recovered and the material could be reused after regeneration. The column test showed that HIOMD could be potentially utilized as an adsorption filtration medium for phosphate removal and recovery from water.

  16. Theoretical and experimental study of the incorporation of tobramycin and strontium-ions into hydroxyapatite by means of co-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Baochang [Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), S 100 44 Stockholm (Sweden); Lilja, Mirjam, E-mail: mirjam.lilja@sandvik.com [Division for Nanotechnology and Functional Materials, The Ångström Laboratory, Uppsala University, 751 21 Uppsala (Sweden); Sandvik Coromant Sverige AB, 12680 Stockholm (Sweden); Ma, Taoran [Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), S 100 44 Stockholm (Sweden); Sörensen, Jan; Steckel, Hartwig [Department of Pharmaceutics and Biopharmaceutics, Christian Albrecht University Kiel, Kiel (Germany); Ahuja, Rajeev [Condensed Matter Theory, Uppala University (Sweden); Strømme, Maria, E-mail: maria.stromme@angstrom.uu.se [Division for Nanotechnology and Functional Materials, The Ångström Laboratory, Uppsala University, 751 21 Uppsala (Sweden)

    2014-09-30

    Highlights: • We investigate incorporation of tobramycin into hydroxyapatite using co-precipitation by theory and experiment. • The drug molecule shows larger adsorption energy on a submicron HA surface compared to a TiO{sub 2} surface. • Strontium substitution allows for production of thinner coatings with enhanced drug incorporation capacity. - Abstract: Antibiotic incorporation into hydroxyapatite (HA) coatings by co-precipitation and the impact of bone relevant doping elements on the adsorption kinetics are investigated from both theoretical and experimental points of view. Tobramycin interactions with bioactive TiO{sub 2} and HA surfaces are analyzed using density functional theory. According to the calculations, the drug molecule has larger adsorption energy than the Ca{sup +} ion on both surfaces under study in Phosphate Buffered Saline (PBS). The results support the experimental observations that HA nucleation and growth are strongly limited on TiO{sub 2} surfaces in the presence of clinically relevant antibiotic concentrations in PBS. The drug molecule is more likely to adopt parallel arrangement onto the HA surface, as the adsorption energy of such arrangement is higher compared to a perpendicular one. Strontium substitution of the HA surface is found to results in a weaker drug–surface interaction, and leads also to a decrease in coating thickness. However, the presence of strontium gives rise to a coating morphology with enhanced drug incorporation capacity and slower antibiotic release compared to non-substituted, co-precipitated counterparts. Our theoretical calculation results were found to be in excellent agreement with experimental data and provide a powerful tool to understand the interaction mechanism between drug and different surface chemistries necessary for development of future versatile orthopedic and dental implant surfaces.

  17. Removal of benzocaine from water by filtration with activated carbon

    Science.gov (United States)

    Howe, G.E.; Bills, T.D.; Marking, L.L.

    1990-01-01

    Benzocaine is a promising candidate for registration with the U.S. Food and Drug Administration for use as an anesthetic in fish culture, management, and research. A method for the removal of benzocaine from hatchery effluents could speed registration of this drug by eliminating requirements for data on its residues, tolerances, detoxification, and environmental hazards. Carbon filtration effectively removes many organic compounds from water. This study tested the effectiveness of three types of activated carbon for removing benzocaine from water by column filtration under controlled laboratory conditions. An adsorptive capacity was calculated for each type of activated carbon. Filtrasorb 400 (12 x 40 mesh; U.S. standard sieve series) showed the greatest capacity for benzocaine adsorption (76.12 mg benzocaine/g carbon); Filtrasorb 300 (8 x 30 mesh) ranked next (31.93 mg/g); and Filtrasorb 816 (8 x 16 mesh) absorbed the least (1.0 mg/g). Increased adsorptive capacity was associated with smaller carbon particle size; however, smaller particle size also impeded column flow. Carbon filtration is a practical means for removing benzocaine from treated water.

  18. Study of calcium carbonate and sulfate co-precipitation

    KAUST Repository

    Zarga, Y.

    2013-06-01

    Co-precipitation of mineral based salts in scaling is still not well understood and/or thermodynamically well defined in the water industry. This study focuses on investigating calcium carbonate (CaCO3) and sulfate mixed precipitation in scaling which is commonly observed in industrial water treatment processes including seawater desalination either by thermal-based or membrane-based processes. Co-precipitation kinetics were studied carefully by monitoring several parameters simultaneously measured, including: pH, calcium and alkalinity concentrations as well as quartz microbalance responses. The CaCO3 germination in mixed precipitation was found to be different than that of simple precipitation. Indeed, the co-precipitation of CaCO3 germination time was not anymore related to supersaturation as in a simple homogenous precipitation, but was significantly reduced when the gypsum crystals appeared first. On the other hand, the calcium sulfate crystals appear to reduce the energetic barrier of CaCO3 nucleation and lead to its precipitation by activating heterogeneous germination. However, the presence of CaCO3 crystals does not seem to have any significant effect on gypsum precipitation. IR spectroscopy and the Scanning Electronic Microscopy (SEM) were used to identify the nature of scales structures. Gypsum was found to be the dominant precipitate while calcite and especially vaterite were found at lower proportions. These analyses showed also that gypsum crystals promote calcite crystallization to the detriment of other forms. © 2013 Elsevier Ltd.

  19. Wet milling versus co-precipitation in magnetite ferrofluid preparation

    Directory of Open Access Journals (Sweden)

    Almásy László

    2015-01-01

    Full Text Available Various uses of ferrofluids for technical applications continuously raise the interest in improvement and optimization of preparation methods. This paper deals with preparation of finely granulated magnetite particles coated with oleic acid in hydrocarbon suspensions following either chemical co-precipitation from iron salt precursors or wet milling of micron size magnetite powder with the goal to compare the benefits and disadvantages of each method. Microstructural measurements showed that both methods gave similar magnetite particle size of 10-15 nm. Higher saturation magnetization was achieved for the wet-milled magnetite suspension compared to relatively rapid co-precipitation synthesis. Different efficacies of ferrophase incorporation into kerosene could be related to the different mechanisms of oleic acid bonding to nanoparticle surface. The comparative data show that wet milling represents a practicable alternative to the traditional co-precipitation since despite of longer processing time, chemicals impact on environment can be avoided as well as the remnant water in the final product.

  20. Filtration properties of nonwovens.

    Science.gov (United States)

    Gador, W; Jankowska, E

    1999-01-01

    This paper presents the results and conclusions from experimental investigations concerning filtration properties of nonwovens. The needled nonwovens were made from polyester fibres (PTE) with average fibre diameter 12 micrometres and polypropylene fibres (PP) with average fibre diameter 32 micrometres. Nonwovens were produced out of each of those fibres or out of a mixture of polyester and polypropylene fibres. This paper also presents investigations of nonwoven fabric made of polypropylene fibres (PP) with average fibre diameter 2.6 micrometres, which was formed according to melt-blown technology. Oil mist, as challenge aerosol, was used to evaluate the performance of filter media at various aerosol velocities. The average oil mist test aerosol particle diameter was 0.3 micrometre. Filter penetration was measured at oil mist concentration 0.24 g/m(3).

  1. Air filtration in HVAC systems

    CERN Document Server

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  2. Bioavailability of adsorbed and coprecipitated Cu, Ni, Pb, and Cd on iron and iron/aluminum hydroxide to Phragmites australis.

    Science.gov (United States)

    Wang, He; Jia, Yongfeng

    2017-01-01

    The bioavailability of heavy metals strongly depends on their speciation in the environment. Adsorption (ADS) and coprecipitation (CPT) on amorphous metal hydroxides are important processes, controlling the fates of heavy metals in an aqueous environment. This work studied the bioavailability of Cu, Cd, Ni, and Pb adsorbed on and/or coprecipitated with amorphous iron and iron/aluminum mixed hydroxides to the wetland plant Phragmites australis. After a 13-day treatment, there was an apparent uptake of the heavy metals by the plant, and the amount of metal bioaccumulation was measurably different for different association forms (ADS vs. CPT). The bioaccumulation of Cd associated with Fe0.5Al0.5(OH)3 was greater than that with Fe(OH)3; the adsorbed metals were found to be more bioavailable than the coprecipitated forms for most of the treatments while the aging treatment significantly reduced the bioaccumulation of ADS metals. In the single metal treatment, root metal concentrations in the Fe(OH)3 ADS system followed the order Ni (68 mg kg(-1)) > Cu (32 mg kg(-1)) > Cd (28 mg kg(-1)) > Pb (9 mg kg(-1)), while the CPT system followed the order of Cu (30 mg kg(-1)) > Ni (22 mg kg(-1)) > Pb (9 mg kg(-1)) > Cd (7 mg kg(-1)). The order of metal accumulation in a combined metal treatment was similar to that for single metal treatments, but observed Ni concentration declines by 22 and 71 % and Cu and Cd concentrations increase by 30 and 50 % (for CPT and ADS treatments, respectively), while Pb concentrations increased by 30~50 % in both of them. When treated with low-molecular-weight organic acids (LMWOAs), metal desorption, indicative of metal oxide bonding strength and metal bioavailability, was consistent with metal accumulation in the plant.

  3. Law of mass action for co-precipitation; Loi d'action de masse de la co-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Vitorge, P

    2008-07-01

    Coprecipitation is often understood as the incorporation of elements at trace concentrations into -initially pure- solid compounds. Coprecipitation has typically been used to identify radioactive isotopes. Coprecipitation can result in lowering solubility as compared to the solubility, when controlled by pure compounds. For this reason it is also important for geochemistry, waste management and de-pollution studies. The solid obtained with coprecipitation is a new homogeneous solid phase called solid solution. The 2 formula needed to calculate the aqueous solubility when controlled by the ideal AB{sub b(1-x)}C{sub cx} solid solutions are K{sub s,B}{sup 1-x}*K{sub s,C}{sup x} equals [A{sup z{sub A}}]*[B{sup z{sub B}}]{sup b(1-x)}*[C{sup z{sub C}}]{sup cx}/((1-x){sup b(1-x)}x{sup cx}) and K{sub s,C}/K{sub s,B} equals (1-x){sup b}*[C{sup z{sub C}}]{sup c}/[B{sup z{sub B}}]{sup b}*x{sup c}), where K{sub s,B} and K{sub s,C} are the classical constant solubility products of the AB{sub b} and AC{sub c} end-members, the b and c values are calculated from the (z{sub i}) charges of the ions and from charge balance. This report is essentially written to provide a thermodynamic demonstration of the law of mass action in attempts to confirm scientific bases for solubility calculations in geosciences (as typically retention of radio-nuclides by co-precipitation), and to facilitate such calculations. Note that the law of mass action is here a set of 2 equations (not only 1) for the ideal or near ideal systems. Since they are consistent with the phase rule, no extra formula (beside mass balance) is needed to calculate the concentrations of all the species in both phases, namely: [A{sup z{sub A}}], [B{sup z{sub B}}], [C{sup z{sub C}}] and specially x.

  4. Emulsions for interfacial filtration.

    Energy Technology Data Exchange (ETDEWEB)

    Grillet, Anne Mary; Bourdon, Christopher Jay; Souza, Caroline Ann; Welk, Margaret Ellen; Hartenberger, Joel David; Brooks, Carlton, F.

    2006-11-01

    We have investigated a novel emulsion interfacial filter that is applicable for a wide range of materials, from nano-particles to cells and bacteria. This technology uses the interface between the two immiscible phases as the active surface area for adsorption of targeted materials. We showed that emulsion interfaces can effectively collect and trap materials from aqueous solution. We tested two aqueous systems, a bovine serum albumin (BSA) solution and coal bed methane produced water (CBMPW). Using a pendant drop technique to monitor the interfacial tension, we demonstrated that materials in both samples were adsorbed to the liquid-liquid interface, and did not readily desorb. A prototype system was built to test the emulsion interfacial filter concept. For the BSA system, a protein assay showed a progressive decrease in the residual BSA concentration as the sample was processed. Based on the initial prototype operation, we propose an improved system design.

  5. Problems of multiphase fluid filtration

    CERN Document Server

    Konovalov, AN

    1994-01-01

    This book deals with a spectrum of problems related to the mathematical modeling of multiphase filtration. Emphasis is placed on an inseparable triad: model - algorithm - computer code. An analysis of new and traditional filtration problems from the point of view of both their numerical implementation and the reproduction of one or another technological characteristics of the processes under consideration is given. The basic principles which underlie the construction of efficient numerical methods taking into account the filtration problems are discussed: non-evolutionary nature, degeneration,

  6. Effect of Calcination at Synthesis of Mg-Al Hydrotalcite Using co-Precipitation Method

    Directory of Open Access Journals (Sweden)

    Niar Kurnia Julianti

    2017-01-01

    Full Text Available The use of hydrotalcite in catalysis has wide attention in academic research and industrial parties. Based on its utilization, hydrotalcite can be active catalyst or support. This research is focused on the investigation of characteristic like spesific surface area of Mg-Al hydrotalcite which is prepared with different temperature of calcination. Synthesis of Mg-Al hydrotalcites with Mg/Al molar ratio 3:1 were prepared by co-precipitation method. Mg(NO33.6H2O and Al(NO33.9H2O as precursors of Mg-Al hydrotalcite. Na2CO3 was used as precipitant agent and NaOH was used as buffer solution. The solution was mixed and aging for 5 hours at 650oC. The dried precipitate was calcined at 2500oC, 3500oC, 4500oC, 5500oC and 6500oC. The characterization of functional group was determined by Fourier Transform Infra Red (FT-IR. The Identical peaks diffractogram were analyzed by X-Ray Diffraction (XRD. The spesific surface area was determined by adsorption-desorption of nitrogen. The largest surface area that obtained from the calcination temperature of 650oC is 156.252 m2/g.

  7. Immobilization of bile salt hydrolase enzyme on mesoporous SBA-15 for co-precipitation of cholesterol.

    Science.gov (United States)

    Bhange, Pallavi; Sridevi, N; Bhange, Deu S; Prabhune, Asmita; Ramaswamy, Veda

    2014-02-01

    We describe herein a simple and effective strategy for immobilization of bile salt hydrolase enzyme by grafting glutaraldehyde groups inside channels of APTES functionalized SBA-15. The increase in glutaraldehyde concentration prevents leakage of enzyme but showed a steep decrease in enzyme activity in the immobilized matrix. So the degree of cross-linking should be the minimum possible to ensure sufficient stability without loss of activity. Cross-linking carried out with 0.1% glutaraldehyde concentration showed the highest activity, so this was used in all further experiments. Physico-chemical characterizations of the immobilized enzyme were carried out by XRD, N2 adsorption, TEM, FTIR and (29)Si CP-MAS NMR techniques. Immobilized BSH exhibits enhanced stability over a wide pH (3-11) and temperature range (40-80 °C) and retains an activity even after recycling experiments and six months of storage. From our in vivo research experiment toward co-precipitation of cholesterol, we have shown that immobilized BSH enzyme may be the promising catalyst for the reduction of serum cholesterol levels in our preliminary investigation. Enhancement in pH stability at the extreme side of pH may favor the use of immobilized BSH enzyme for drug delivery purpose to with stand extreme pH conditions in the gastrointestinal conditions.

  8. Latest aspects of mechanical filtration

    Directory of Open Access Journals (Sweden)

    Stanislav Koláček

    2013-01-01

    Full Text Available The aim of this study was to describe and unify all knowledge about mechanic filtration. The first part deals with the parameters and properties of filtration. Here some important basic concepts are explained such as pressure gradient, filter life, etc. There’s also a description of convenient filtration technology for coarse and fine materials, such as sand, smoke or soot. The second part primarily focuses on the real use and application of filters for liquid and gaseous media. The differences in construction between different types of filters for filtration of fuels, oils, hydraulic fluids, air and cabin filters are described. The last section is focused mainly on new materials for the production of filters. These materials are ceramic or nanomaterials, which can actually be enriched for example with antibacterial silver or some fungicides.

  9. Health benefits of particle filtration.

    Science.gov (United States)

    Fisk, W J

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, for example, 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  10. Health Benefits of Particle Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  11. Health Benefits of Particle Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  12. Virus removal vs. subsurface water velocity during slow sand filtration.

    Science.gov (United States)

    Dizer, Halim; Brackmann, Bernhard; Rahman, M Azizur; Szewzyk, Regine; Sprenger, Christoph; Holzbecher, Ekkehard; López-Pila, Juan M

    2015-06-01

    In an attempt to obtain a conservative estimate of virus removal during slow sand and river bank filtration, a somatic phage was isolated with slow decay and poor adsorption to coarse sand. We continuously fed a phage suspension to a 7-m infiltration path and measured the phage removal. In a second set of experiments, we fed the phage suspension to 1-m long columns run at different pore water velocities. Using the data obtained, a mathematical model was constructed describing removal vs. pore water velocity (PWV), assuming different statistical distributions of the adsorption coefficient λ. The bimodal distribution best fit the results for PWVs higher than 1 m/d. It predicted a removal of approximately 4 log10 after 50 days infiltration at 1 m/d. At PWVs below 1 m/d the model underestimated removal. Sand-bound phages dissociated slowly into the liquid phase, with a detachment constant kdet of 2.6 × 10⁻⁵. This low kdet suggests that river bank filtration plants should be intermittently operated when viral overload is suspected, e.g. during flooding events or at high water-marks in rivers, in order for viruses to become soil-associated during the periods of standstill. Resuming filtration will allow only a very slow virus release from the soil.

  13. Filtration and compression of organic materials

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Keiding, Kristian

    The conventional filtration theory has been based on filtrations of incompressible particles such as anatase, kaolin and clay. The filtration models have later been used for organic slurries but can often not explain the observed experimental data. At constant pressure, the filtrate volume does...

  14. 40 CFR 141.73 - Filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration. 141.73 Section 141.73... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system..., and does not meet all of the criteria in § 141.71 (a) and (b) for avoiding filtration, must...

  15. Novel sandwich structure adsorptive membranes for removal of 4-nitrotoluene from water

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yuexin [College of Chemistry, Beijing Normal University, Beijing 100875 (China); School of Pharmacy, North China University of Science and Technology, Tangshan 063000 (China); Jia, Zhiqian, E-mail: zhqjia@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China)

    2016-11-05

    Highlights: • Novel sandwich PES-SPES/PS-PDVB/PTFE adsorptive membranes were prepared. • The removal efficiency for 4-nitrotoluene is greater than 95% after five recycles. • The membrane showed higher adsorption capacity than that of mixed matrix membrane. - Abstract: Novel sandwich PES-SPES/PS-PDVB/PTFE adsorptive membranes were prepared by a filtration/immersion precipitation method and employed for the removal of 4-nitrotoluene from water. The static adsorption thermodynamics, kinetics, dynamic adsorption/desorption and membrane reusability were investigated. The results showed that the Freundlich model describes the adsorption isotherm satisfactorily. With increased PS-PDVB content, the maximum static adsorption capacity, partition coefficient, apparent adsorption rate constant, and dynamic adsorption capacity all significantly increased. The sandwich membranes showed much higher removal efficiency and adsorption capacity than those of mixed matrix membranes. With respect to dynamics adsorption/desorption, the sandwich membranes exhibited excellent reusability, with a removal efficiency greater than 95% even after five recycles.

  16. Flame atomic absorption spectrometric determination of heavy metals in aqueous solution and surface water preceded by co-precipitation procedure with copper(II) 8-hydroxyquinoline

    Science.gov (United States)

    Ipeaiyeda, Ayodele Rotimi; Ayoade, Abisayo Ruth

    2017-07-01

    Co-precipitation procedure has widely been employed for preconcentration and separation of metal ions from the matrices of environmental samples. This is simply due to its simplicity, low consumption of separating solvent and short duration for analysis. Various organic ligands have been used for this purpose. However, there is dearth of information on the application of 8-hydroxyquinoline (8-HQ) as ligand and Cu(II) as carrier element. The use of Cu(II) is desirable because there is no contamination and background adsorption interference. Therefore, the objective of this study was to use 8-HQ in the presence of Cu(II) for coprecipitation of Cd(II), Co(II), Cr(III), Ni(II) and Pb(II) from standard solutions and surface water prior to their determinations by flame atomic absorption spectrometry (FAAS). The effects of pH, sample volume, amount of 8-HQ and Cu(II) and interfering ions on the recoveries of metal ions from standard solutions were monitored using FAAS. The water samples were treated with 8-HQ under the optimum experimental conditions and metal concentrations were determined by FAAS. The metal concentrations in water samples not treated with 8-HQ were also determined. The optimum recovery values for metal ions were higher than 85.0%. The concentrations (mg/L) of Co(II), Ni(II), Cr(III), and Pb(II) in water samples treated with 8-HQ were 0.014 ± 0.002, 0.03 ± 0.01, 0.04 ± 0.02 and 0.05 ± 0.02, respectively. These concentrations and those obtained without coprecipitation technique were significantly different. Coprecipitation procedure using 8-HQ as ligand and Cu(II) as carrier element enhanced the preconcentration and separation of metal ions from the matrix of water sample.

  17. A Coprecipitation Coating Synthesis of SiC/YAG Composites

    Institute of Scientific and Technical Information of China (English)

    Ning ZHANG; Hongqiang RU; Xudong SUN; Qingkui CAI

    2004-01-01

    The α-SiC in 0.5 μm size powders were coated with Al2O3 and Y2O3 by a coprecipitation coating (CPC) method for fabrication of SiC/YAG composites. The same powder preparation was carried out by conventional mechanical mixing (MM) method for comparison. Two kinds of SiC/YAG composites were manufactured by pressureless sintering using the different powders, named CPC composite and MM composite thereafter respectively. It is shown that the CPC composite has the advantages of homogeneous distribution of YAG phase and of being sintered to high density at a low temperature, 100℃ lower than that of MM composite. The strength (573 Mpa) and hardness (23.3 Gpa) of the CPC composite are significantly higher than those (323 Mpa and 13.5 Gpa) of the MM composite, respectively.

  18. Preparation of ITO Nanoparticles by Liquid Phase Coprecipitation Method

    Directory of Open Access Journals (Sweden)

    Zhanlai Ding

    2010-01-01

    Full Text Available The nanoscale indium tin oxide (ITO particles are synthesied by liquid phase coprecipitation method under given conditions with solution of indium chloride, tin chloride, and ammonia. The absolute ethyl alcohol or deionized water was used as solvent and the dodecylamine or hexadecylamine surfactant was used as a dispersant in the reaction system. The sample powder was characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, and high-resolution electron microscopy (HRTEM. Based on the transmission electron micrograph, the influences of the two different solvents and the two different dispersants on the nanoparticle size and dispersion were studied, respectively. The results showed that the ITO particles are finely crystallized body-centered cubic structure. The particle size has distributed in 30 nm to 90 nm.

  19. Modified coprecipitation process of synthesizing Bi-system superconductor precursor powder and its stoichiometry

    Institute of Scientific and Technical Information of China (English)

    毛传斌; 杜泽华; 周廉

    1996-01-01

    A modified coprecipitation process is presented based on the stoichiometry study of oxalate coprecipitation process in water medium to synthesize Bi-Pb-Sr-Ca-Cu-O multi-component powder.Its characteristic is that the coprecipitation reaction takes place in a mixed solution medium composed of water and a kind of organic solvent (volume percentage >90%).Thus,it overcomes the serious shortcoming of inability to maintain stoichiometry in Bi-system superconductor powder synthesized by water-medium coprecipitation.The effects of pH value,oxalic acid concentration and aging time on stoichiometry maintenance in precipitate are systematically studied.Bulk material made from the powder prepared by the new modified coprecipitation also shows the success of the new process.

  20. How to dose powdered activated carbon in deep bed filtration for efficient micropollutant removal.

    Science.gov (United States)

    Altmann, Johannes; Ruhl, Aki S; Sauter, Daniel; Pohl, Julia; Jekel, Martin

    2015-07-01

    Direct addition of powdered activated carbon (PAC) to the inlet of a deep bed filter represents an energy- and space-saving option to remove organic micropollutants (OMPs) during advanced wastewater treatment or drinking water purification. In this lab-scale study, continuous dosing, preconditioning a filter with PAC and combinations thereof were investigated as possible dosing modes with respect to OMP adsorption efficiency. Continuous dosing resulted in decreasing effluent concentrations with increasing filter runtime due to adsorption onto accumulating PAC in the filter bed. Approximately constant removal levels were achieved at longer filter runtimes, which were mainly determined by the dose of fresh PAC, rather than the total PAC amount embedded. The highest effluent concentrations were observed during the initial filtration stage. Meanwhile, preconditioning led to complete OMP adsorption at the beginning of filtration and subsequent gradual OMP breakthrough. PAC distribution in the pumice filter was determined by the loss on ignition of PAC and pumice and was shown to be relevant for adsorption efficiency. Preconditioning with turbulent upflow led to a homogenous PAC distribution and improved OMP adsorption significantly. Combining partial preconditioning and continuous dosing led to low initial effluent concentrations, but ultimately achieved concentrations similar to filter runs without preconditioning. Furthermore, a dosing stop prior to the end of filtration was suitable to increase PAC efficiency without affecting overall OMP removals.

  1. Cake creep during filtration of flocculated manure

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Keiding, Kristian

    the distribution of N and P on the fields. Filtration is a useful method for such a separation. Furthermore, chemicals can be added to flocculate the solids and thereby increase the filterability i.e. the specific filter-cake resistance can be reduced from 1015 m/kg to 1011 m/kg. Both the amount of added chemicals......, and the mixing procedure affect the result, and lab-scale experiments are often used to study how these pre-treatments influence the filtration process. However, the existing mathematical filtration models are based on filtration of inorganic particles and cannot simulate the filtration data obtained when manure...... that the discrepancy between the filtration theory and the observed filtration behaviour is due to a time-dependent collapse of the formed cake (creep). This can also explain the observed behaviour when flocculated manure is filtered. The filtration data can be simulated if cake creep is adopted in the filtration...

  2. STUDY ON FIBROUS COMPOSITES BEHAVIOUR IN HYDRODYNAMIC PROCESS OF WINE FILTRATION

    Directory of Open Access Journals (Sweden)

    Petronela Nechita

    2009-11-01

    Full Text Available This study concerns the implementation and performance evaluation of fibrous composites in sterile filtration of wine. Conditions of preparation were established having in view that the separation of particulate contaminants from liquids by depth filtration is occurring by mechanical entrapment into structural pores and by electrokinetic adsorption, and both retention mechanisms are influenced by various factors. Functional characteristics and behaviour of the filtering composite in industrial filtration of wine were evaluated. It was found that the effectiveness with which micro-organisms were retained was substantially improved by a porous structure characterized by small pores, and respectively by high resistance to air filtration, as well as by a higher content of cationic charges in the system.

  3. Improving IAQ Via Air Filtration.

    Science.gov (United States)

    Monk, Brian

    1999-01-01

    Provides tips on using air filtration to control indoor air quality in educational facilities, including dedicated spaces with unique air quality conditions such as in libraries, museums and archival storage areas, kitchens and dining areas, and laboratories. The control of particulate contaminants, gaseous contaminants, and moisture buildup are…

  4. Filtration combustion: Smoldering and SHS

    Science.gov (United States)

    Matkowsky, Bernard J.

    1995-01-01

    Smolder waves and SHS (self-propagating high-temperature synthesis) waves are both examples of combustion waves propagating in porous media. When delivery of reactants through the pores to the reaction site is an important aspect of the process, it is referred to as filtration combustion. The two types of filtration combustion have a similar mathematical formulation, describing the ignition, propagation and extinction of combustion waves in porous media. The goal in each case, however, is different. In smoldering the desired goal is to prevent propagation, whereas in SHS the goal is to insure propagation of the combustion wave, leading to the synthesis of desired products. In addition, the scales in the two areas of application may well differ. For example, smoldering generally occurs at a relatively low temperature and with a smaller propagation velocity than SHS filtration combustion waves. Nevertheless, the two areas of application have much in common, so that mechanisms learned about in one application can be used to advantage in the other. In this paper we discuss recent results in the areas of filtration combustion.

  5. Demonstration of creep during filtration

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Bugge, Thomas Vistisen; Kirchheiner, Anders Løvenbalk

    The classical filtration theory assumes a unique relationship between the local filter cake porosity and the local effective pressure. For a number of compressible materials, it has however been observed that during the consolidation stage this may not be the case. It has been found that the prod......The classical filtration theory assumes a unique relationship between the local filter cake porosity and the local effective pressure. For a number of compressible materials, it has however been observed that during the consolidation stage this may not be the case. It has been found...... that the production of filtrate also depends on the characteristic time for the filter cake solids to deform. This is formulated in the Terzaghi-Voigt model in which a secondary consolidation is introduced. The secondary consolidation may be visualized by plots of the relative cake deformation (U) v.s. the square...... magnitude as the primary consolidation (defined by the hydraulic retardation), the creep phenomenon may occur during filtration. This will lead to Ruth's plots characterized by a concave with two (more or less) distinct slopes. The slopes are defined by the relationship between the porosity...

  6. Technetium (VII) Co-precipitation with Framework Aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Harsh, James B. [Washington State Univ., Pullman, WA (United States); Dickson, Johnbull Otah [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pierce, Eric M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bargar, John [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-07-13

    Technetium-99 (99Tc), a long-lived radionuclide, is one of the most widespread contaminants within the Hanford subsurface. At some depths, it is only extractable with strong acids, suggesting incorporation into a solid phase. We hypothesized that Tc may have coprecipitated with feldspathoid aluminosilicates under waste tanks that had leaked caustic solutions into the vadose zone. Our objectives were to determine if Tc could be incorporated into the feldspathoids cancrinite and sodalite and under what conditions coprecipitation could occur. Our hypothesis was that sodalite was more likely to incorporate and retain Tc. Our approach was to use known methods of feldspathoid formation in solutions resembling those in Hanford waste tanks contacting sediments in terms of major ion (Na, NO3, OH, Al(OH)4, and Si(OH)4 concentrations. In some cases, Al and Si were supplied from zeolite. We used perrhenate (ReO4) as a surrogate for pertechnetate (TcO4) to avoid the radioactivity. The major findings of this study were 1) ReO4 could be incorporated into either sodalite or cancrinite but the concentration in the solid was < 1% of the competing ion Cl, NO3, or NO2. 2) The small amount of ReO4 incorporated was not exchangeable with NO3 or NO2. 3) In sodalite, NO3 was highly preferred over ReO4 but significant Re-sodalite was formed when the mole fraction in solution (Re/Re+N) exceeded 0.8. 4) A nonlinear relation between the unit cell parameter and amount of Re incorporated suggested that a separate Re-sodalite phase was formed rather than a solid solution. 5) We determined that sodalite preference for sodalite in the presence of different anions increased with the ionic size of the competing anion: Cl < CO3 < NO3 < SO4 < MnO4 < WO4 and significant incorporation did not occur unless the difference in anion radii was less than 12%. 6) Re(VII) was not significantly reduced to Re(IV) under the conditions of this experiment and Re appeared to be a good surrogate for Tc under oxidizing

  7. Alkaline Earth Element Adsorption onto PAA-Coated Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Qing Wang

    2017-02-01

    Full Text Available In this paper, we present a study on the adsorption of calcium (Ca2+ onto polyacrylic acid-functionalized iron-oxide magnetic nanoparticles (PAA-MNPs to gain an insight into the adsorption behavior of alkaline earth elements at conditions typical of produced water from hydraulic fracturing. An aqueous co-precipitation method was employed to fabricate iron oxide magnetic nanoparticles, whose surface was first coated with amine and then by PAA. To evaluate the Ca2+ adsorption capacity by PAA-MNPs, the Ca2+ adsorption isotherm was measured in batch as a function of pH and sodium chlorite (electrolyte concentration. A surface complexation model accounting for the coulombic forces in the diffuse double layer was developed to describe the competitive adsorption of protons (H+ and Ca2+ onto the anionic carboxyl ligands of the PAA-MNPs. Measurements show that Ca2+ adsorption is significant above pH 5 and decreases with the electrolyte concentration. Upon adsorption, the nanoparticle suspension destabilizes and creates large clusters, which favor an efficient magnetic separation of the PAA-MNPs, therefore, helping their recovery and recycle. The model agrees well with the experiments and predicts that the maximum adsorption capacity can be achieved within the pH range of the produced water, although that maximum declines with the electrolyte concentration.

  8. Filtration Understanding: FY10 Testing Results and Filtration Model Update

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Richard C.; Billing, Justin M.; Burns, Carolyn A.; Peterson, Reid A.; Russell, Renee L.; Schonewill, Philip P.; Shimskey, Rick W.

    2011-04-04

    This document completes the requirements of Milestone 2-4, Final Report of FY10 Testing, discussed in the scope of work outlined in the EM31 task plan WP-2.3.6-2010-1. The focus of task WP 2.3.6 is to improve the U.S. Department of Energy’s (DOE’s) understanding of filtration operations for high-level waste (HLW) to improve filtration and cleaning efficiencies, thereby increasing process throughput and reducing the Na demand (through acid neutralization). Developing the cleaning/backpulsing requirements will produce much more efficient operations for both the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and the Savannah River Site (SRS), thereby significantly increasing throughput by limiting cleaning cycles. The scope of this work is to develop the understanding of filter fouling to allow developing this cleaning/backpulsing strategy.

  9. 40 CFR 141.173 - Filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration. 141.173 Section 141.173... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that...

  10. Chemical filtration of Cr (VI) with electrospun chitosan nanofiber membranes.

    Science.gov (United States)

    Li, Lei; Li, Yanxiang; Yang, Chuanfang

    2016-04-20

    Chitosan nanofibers (average diameter of 75nm) were electrospun on polyester (PET) scrim to form composite nanofiber membranes with controlled pore size. The membranes were then stacked as a membrane bed for chemical filtration of Cr (VI) of 1-5mg/L. The performance of the bed with respect to loading capacity at breakthrough, bed saturation and utilization efficiency were carefully investigated. The results showed that while these three parameters were dependent on pH, flow rate, flow distribution and packed pattern of the membrane, the latter two were less affected by feed Cr (VI) concentration and bed length. The maximum bed loading capacity for 1mg/L Cr (VI) filtration at breakthrough was found to be 16.5mg-chromium/g-chitosan, higher than the static adsorption capacity of 11.0mg-chromium/g-chitosan using nanofiber mats, indicating the membranes' better potential for dynamic adsorption. The minimum bed length required to avoid breakthrough was determined to be three layers of stacked membranes with nanofiber deposition density of 1g/m(2) by applying bed depth service time (BDST) model.

  11. Co-precipitation in aqueous solution synthesis of magnetite nanoparticles using iron(III salts as precursors

    Directory of Open Access Journals (Sweden)

    Mutasim I. Khalil

    2015-03-01

    Full Text Available An innovative quantitative synthetic method for preparing magnetite nanoparticles was achieved by co-precipitation in aqueous solution using only one single iron(III salt as a precursor. A 2 Fe(III:1 Fe(II mole ratio was first attained in solution by reducing iron(III using KI solution, followed by filtering the iodine formed and hydrolyzing the filtrate by 25% ammonium hydroxide solution at pH 9–11. A high selectivity and atom economy percents were achieved indicating that the method is environmentally benign and green. The as-synthesized nanoparticles were characterized by fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, field emission transmission electron microscopy (FETEM, selected area electron diffraction (SAED, and 57Fe Mössbauer spectroscopy. Magnetite nanocrystals (d: 7.84 ± 0.05 nm and nanorods (d: 6.3 ± 0.2 nm; l: 46.2 ± 0.9 formation was evident.

  12. Mobile surface water filtration system

    Directory of Open Access Journals (Sweden)

    Aashish Vatsyayan

    2012-09-01

    Full Text Available To design a mobile system for surface water filtrationMethodology: the filtration of surface impurities begins with their retraction to concentrated thickness using non ionising surfactants, then isolation using surface tension property and sedimentation of impurities in process chamber using electrocoagulation. Result:following studies done to determine the rate of spreading of crude oil on water a method for retraction of spread crude oil to concentrated volumes is developed involving addition of non -ionising surfactants in contrast to use of dispersants. Electrocoagulation process involves multiple processes taking place to lead to depositionof impurities such as oil, grease, metals. Studies of experiments conducted reveals parameters necessary for design of electrocoagulation process chamber though a holistic approach towards system designing is still required. Propeller theory is used in determining the required design of propeller and the desired thrust, the overall structure will finally contribute in deciding the choice of propeller.

  13. Centrifugal membrane filtration -- Task 9

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., the developer of a centrifugal membrane filtration technology, to demonstrate applications for the SpinTek technology within the US Department of Energy (DOE) Environmental management (EM) Program. The technology uses supported microporous membranes rotating at high rpm, under pressure, to separate suspended and colloidal solids from liquid streams, yielding a solids-free permeate stream and a highly concentrated solids stream. This is a crosscutting technology that falls under the Efficient Separations and Processing Crosscutting Program, with potential application to tank wastes, contaminated groundwater, landfill leachate, and secondary liquid waste streams from other remediation processes, including decontamination and decommissioning systems. Membrane-screening tests were performed with the SpinTek STC-X4 static test cell filtration unit, using five ceramic membranes with different pore size and composition. Based on permeate flux, a 0.25-{micro}m TiO{sub 2}/Al{sub 2}O{sub 3} membrane was selected for detailed performance evaluation using the SpinTek ST-IIL centrifugal membrane filtration unit with a surrogate tank waste solution. An extended test run of 100 hr performed on a surrogate tank waste solution showed some deterioration in filtration performance, based on flux, apparently due to the buildup of solids near the inner portion of the membrane where relative membrane velocities were low. Continued testing of the system will focus on modifications to the shear pattern across the entire membrane surface to affect improved long-term performance.

  14. Cake Filtration in Viscoelastic Polymer Solutions

    Science.gov (United States)

    Surý, Alexander; Machač, Ivan

    2009-07-01

    In this contribution, the filtration equations for a cake filtration in viscoelastic fluids are presented. They are based on a capillary hybrid model for the flow of a power law fluid. In order to express the elastic pressure drop excess in the flow of viscoelastic filtrate through the filter cake and filter screen, modified Deborah number correction functions are included into these equations. Their validity was examined experimentally. Filtration experiments with suspensions of hardened polystyrene particles (Krasten) in viscoelastic aqueous solutions of polyacryl amides (0.4% and 0.6%wt. Kerafloc) were carried out at a constant pressure on a cylindrical filtration unit using filter screens of different resistance.

  15. Comparative study of the coprecipitation methods for the preparation of Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Crepaldi Eduardo L.

    2000-01-01

    Full Text Available Coprecipitation is the method most frequently applied to prepare Layered Double Hydroxides (LDHs. Two variations of this method can be used, depending on the pH control conditions during the precipitation step. In one case the pH values are allowed to vary while in the other they are kept constant throughout coprecipitation. Although research groups have their preferences, no systematic comparison of the two variations of the coprecipitation method is available in the literature. On this basis, the objective of the present study was to compare the properties of LDHs prepared using the two forms of pH control in the coprecipitation method. The results showed that even though coprecipitation is easier to perform under conditions of variable pH values, materials with more interesting properties, from the point of view of technological applications, are obtained at constant pH. Higher crystallinity, smaller particle size, higher specific surface area and higher average pore diameter were found for materials obtained by coprecipitation at constant pH, when compared to the materials obtained at variable pH.

  16. Gd-DTPA Adsorption on Chitosan/Magnetite Nanocomposites

    Science.gov (United States)

    Pylypchuk, Ie. V.; Kołodyńska, D.; Kozioł, M.; Gorbyk, P. P.

    2016-03-01

    The synthesis of the chitosan/magnetite nanocomposites is presented. Composites were prepared by co-precipitation of iron(II) and iron(III) salts by aqueous ammonia in the 0.1 % chitosan solution. It was shown that magnetite synthesis in the chitosan medium does not affect the magnetite crystal structure. The thermal analysis data showed 4.6 % of mass concentration of chitosan in the hybrid chitosan/magnetite composite. In the concentration range of initial Gd-DTPA solution up to 0.4 mmol/L, addition of chitosan to magnetite increases the adsorption capacity and affinity to Gd-DTPA complex. The Langmuir and Freundlich adsorption models were applied to describe adsorption processes. Nanocomposites were characterized by scanning electron microscopy (SEM), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and specific surface area determination (ASAP) methods.

  17. Surface chemistry of ferrihydrite: Part 1. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate

    Science.gov (United States)

    Waychunas, G. A.; Rea, B. A.; Fuller, C. C.; Davis, J. A.

    1993-05-01

    EXAFS spectra were collected on both the As and Fe K-edges from samples of two-line ferrihydrite with adsorbed (ADS) and coprecipitated (CPT) arsenate prepared over a range of conditions and arsenate surface coverages. Spectra also were collected for arsenate adsorbed on the surfaces of three FeOOH crystalline polymorphs, α (goethite), β (akaganeite), and γ (lepidocrocite), and as a free ion in aqueous: solution. Analyses of the As EXAFS show clear evidence for inner sphere bidentate (bridging) arsenate complexes on the ferrihydrite surface and on the surfaces of the crystalline FeOOH polymorphs. The bridging arsenate is attached to adjacent apices of edge-sharing Fe oxyhydroxyl octahedra. The arsenic-iron distance at the interface ( 3.28 ±0.01 Å) is close to that expected for this geometry on the FeOOH polymorph surfaces, but is slightly shorter on the ferrihydrite surfaces ( 3.25 ± 0.02 Å). Mono-dentate arsenate linkages ( 3.60 ± 0.03 Å) also occur on the ferrihydrite, but are not generally observed on the crystalline FeOOH polymorphs. The proportion of monodentate bonds appears largest for adsorption samples with the smallest As/Fe molar ratio. In all cases the arsenate tetrahedral complex is relatively undistorted with As-O bonds of 1.66 ± 0.01 Å. Precipitation of arsenate or scorodite-like phases was not observed for any samples, all of which were prepared at a pH value of 8. The Fe EXAFS results confirm that the Fe-Fe correlations in the ferrihydrite are progressively disrupted in the CPT samples as the As/Fe ratio is increased. Coherent crystallite size is probably no more than 10 Å in diameter and no Fe oxyhydroxyl octahedra corner-sharing linkages (as would be present in FeOOH polymorphs) are observed at the largest As/Fe ratios. Comparison of the number and type of Fe-Fe neighbors with the topological constraints imposed by the arsenate saturation limit in the CPT samples (about 0.7 As/Fe) indicates ferrihydrite units consisting mainly of Fe

  18. Adsorption of proteins from plasma at polyester non-wovens

    NARCIS (Netherlands)

    Klomp, A.J.A.; Engbers, G.H.M.; Mol, J.; Terlingen, J.G.A.; Feijen, J.

    1999-01-01

    Polyester non-wovens in filters for the removal of leukocytes from platelet concentrates (PCs) must be platelet compatible. In PC filtration, the adsorption of proteins at the plasma–non-woven interface can be of great importance with respect to the yield of platelets. Unmodified and radio frequency

  19. Water Filtration Using Plant Xylem

    CERN Document Server

    Lee, Jongho; Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2013-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees - a readily available, inexpensive, biodegradable, and disposable material - can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings.

  20. Adsorption of heavy metal in freeway by asphalt block

    Science.gov (United States)

    Zheng, Chaocheng

    2017-08-01

    Heavy metals are toxic, persistent, and carcinogenic in freeway. Various techniques are available for the removal of heavy metals from waste water among soils during freeway including ion-exchange, membrane filtration, electrolysis, coagulation, flotation, and adsorption. Among them, bio-sorption processes are widely used for heavy metal and other pollutant removal due to its sustainable, rapid and economic. In this paper, heavy metal removal facilitated by adsorption in plants during freeway was illustrated to provide concise information on exploring the adsorption efficiency.

  1. Highly selective hydrogenation of CO2 to methanol over CuO-ZnO-ZrO2 catalysts prepared by a surfactant-assisted co-precipitation method

    Science.gov (United States)

    Li, Li; Mao, Dongsen; Yu, Jun; Guo, Xiaoming

    2015-04-01

    A series of CuO-ZnO-ZrO2 catalysts are synthesized by a surfactant-assisted co-precipitation method and tested for the synthesis of methanol from CO2 hydrogenation. The effects of calcination temperature on the physicochemical properties of as-prepared catalysts are investigated extensively by TG-DSC, N2 adsorption/desorption, XRD, N2O chemisorption, SEM/TEM, EDX, XPS, TPR, H2-TPD and CO2-TPD techniques. The results show that the size of copper particles increases with the increase in calcination temperature, leading to the decrease in turnover frequency (TOF) for methanol formation. Moreover, compared with the counterparts prepared by the conventional co-precipitation method, the CuO-ZnO-ZrO2 catalysts prepared by this novel method show significantly high methanol selectivity. The superior property of the prepared CuO-ZnO-ZrO2 catalyst can be attributed to the formation of more amounts of Cu-ZnOx and/or Cu-ZrOx species resulted from the homogeneous element distribution, intimate interface contact of Cu species with ZnO and/or ZrO2, and to porous structure with larger pore size.

  2. Structural and magnetic properties of nano-sized NiCuZn ferrites synthesized by co-precipitation method with ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Harzali, Hassen, E-mail: harzali@mines-albi.fr [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Saida, Fairouz; Marzouki, Arij; Megriche, Adel [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Baillon, Fabien; Espitalier, Fabienne [Université de Toulouse, Mines Albi, CNRS, Centre RAPSODEE, Campus Jarlard, F-81013 Albi CT cedex 09 (France); Mgaidi, Arbi [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Taibah University, Faculty of Sciences & art, Al Ula (Saudi Arabia)

    2016-12-01

    Sonochemically assisted co-precipitation has been used to prepare nano-sized Ni–Cu–Zn-ferrite powders. A suspension of constituent hydroxides was ultrasonically irradiated for various times at different temperatures with high intensity ultrasound radiation using a direct immersion titanium horn. Structural and magnetic properties were investigated using X-diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), Nitrogen adsorption at 77 K (BET) and Vibrating sample magnetometer (VSM). Preliminary experimental results relative to optimal parameters showed that reaction time t=2 h, temperature θ=90 °C and dissipated Power P{sub diss}=46.27 W. At these conditions, this work shows the formation of nanocrystalline single-phase structure with particle size 10–25 nm. Also, ours magnetic measurements proved that the sonochemistry method has a great influence on enhancing the magnetic properties of the ferrite. - Highlights: • Coprecipitation experiments were carried out with ultrasound. • The spinel ferrite NiCuZn was perfectly synthesized by ultrasound. • The saturation magnetization and crystals size are found to be correlated as the dissipated power was varied.

  3. Uranium isotope fractionation during coprecipitation with aragonite and calcite

    Science.gov (United States)

    Chen, Xinming; Romaniello, Stephen J.; Herrmann, Achim D.; Wasylenki, Laura E.; Anbar, Ariel D.

    2016-09-01

    Natural variations in 238U/235U of marine calcium carbonates might provide a useful way of constraining redox conditions of ancient environments. In order to evaluate the reliability of this proxy, we conducted aragonite and calcite coprecipitation experiments at pH ∼7.5 and ∼8.5 to study possible U isotope fractionation during incorporation into these minerals. Small but significant U isotope fractionation was observed in aragonite experiments at pH ∼8.5, with heavier U isotopes preferentially enriched in the solid phase. 238U/235U of dissolved U in these experiments can be fit by Rayleigh fractionation curves with fractionation factors of 1.00007 + 0.00002/-0.00003, 1.00005 ± 0.00001, and 1.00003 ± 0.00001. In contrast, no resolvable U isotope fractionation was observed in an aragonite experiment at pH ∼7.5 or in calcite experiments at either pH. Equilibrium isotope fractionation among different aqueous U species is the most likely explanation for these findings. Certain charged U species are preferentially incorporated into calcium carbonate relative to the uncharged U species Ca2UO2(CO3)3(aq), which we hypothesize has a lighter equilibrium U isotope composition than most of the charged species. According to this hypothesis, the magnitude of U isotope fractionation should scale with the fraction of dissolved U that is present as Ca2UO2(CO3)3(aq). This expectation is confirmed by equilibrium speciation modeling of our experiments. Theoretical calculation of the U isotope fractionation factors between different U species could further test this hypothesis and our proposed fractionation mechanism. These findings suggest that U isotope variations in ancient carbonates could be controlled by changes in the aqueous speciation of seawater U, particularly changes in seawater pH, PCO2 , Ca2+, or Mg2+ concentrations. In general, these effects are likely to be small (<0.13‰), but are nevertheless potentially significant because of the small natural range of

  4. Formation and stability of aluminosilicate colloids by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Putri, Kirana Yuniati

    2011-02-15

    Colloids are ubiquitous in natural waters. Colloid-facilitated migration is of importance in safety assessment of a nuclear waste disposal. Aluminosilicate colloids are considered to be the kernel of aquatic colloids. Their stability is affected by a number of geochemical parameters. This work aims to study qualitatively and quantitatively the stability of aluminosilicate colloids formed by coprecipitation under various geochemical conditions, i.e. pH, concentration of Al and Si metal ions, ionic strength, and omnipresent cations (Na{sup +}, Ca{sup 2+}, and Mg{sup 2+}). The work is performed by colorimetric method and laser-induced breakdown detection (LIBD). Two consecutive phase separations at 450 nm and 1 kDa are applied to separate the precipitates and colloids from the ionic species. By means of colorimetry, Si and Al can be detected down to 5.8 x10{sup -8} M and 7.4x10{sup -7} M, respectively. On the other hand, LIBD is able to quantify the colloidal size and its number density down to several ppt. Depending on the concentration of Al and Si metal ions, the formation trend of aluminosilicate colloid changes following its solubility curve. The lower the concentration, the higher the pH range in which the colloids start to emerge. Furthermore, the colloids are stable at higher Al and Si concentration and at low ionic strength. In the low pH range, cations provide different effects at low and high ionic strengths. At high ionic strength, the colloids are stable in the presence of a larger cation, while all cations exhibit similar effects at low ionic strength. However, in the high pH range, valence seems to have a stronger effect than ionic radius; colloids are more stable in the presence of monovalent cations than divalent ones. Meanwhile, XRD shows non- and/or poor crystalline structure of the aluminosilicate species. Nevertheless, results from XPS may suggest that the chemical composition (Si/Al ∼ 0.6) of the aluminosilicate precipitates is sillimanite or

  5. Pig manure treatment and purification by filtration.

    Science.gov (United States)

    Makara, A; Kowalski, Z

    2015-09-15

    This study aimed to develop a new, complex pig manure treatment and filtration process. The final scheme, called the AMAK process, comprised the following successive steps: mineralization with mineral acids, alkalization with lime milk, superphosphate addition, a second alkalization, thermal treatment, and pressure filtration. The proposed method produced a filtrate with 95%, 80%, and 96% reductions in chemical oxygen demand, nitrogen content, and phosphorus content, respectively. An advantage of the proposed method was that it incorporated a crystalline phase into the solid organic part of the manure, which enabled high filtration rates (>1000 kg m(-2) h(-1)) and efficient separation. The process also eliminated odor emissions from the filtrate and sediment. The treated filtrate could be used to irrigate crops or it could be further treated in conventional biological wastewater treatment plants. The sediment could be used for producing mineral-organic fertilizer. The AMAK process is inexpensive, and it requires low investment costs.

  6. Characterization of CeO2-ZrO2 mixed oxides prepared by two different co-precipitation methods

    Institute of Scientific and Technical Information of China (English)

    YUE Mei; CUI Meisheng; ZHANG Na; LONG Zhiqi; HUANG Xiaowei

    2013-01-01

    A series of cerium zirconium mixed oxides were prepared by two co-precipitation methods using magnesium hydrogen carbonate (MHC) and mixed ammonia-ammonia hydrogen carbonate (AAHC) as precipitant respectively.The crystal structure,BET surface area and morphology of the produced cerium zirconium mixed oxides were characterized by X-ray diffraction (XRD),Brumauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) techniques.The reduction-oxidation behavior and oxygen storage capacity (OSC) performance were also studied by temperature programmed reduction (TPR) and oxygen pulse chemical adsorption methods.The XRD results demonstrated that the cerium zirconium mixed oxides obtained by both methods possessed structure of cubic solid solution phase.The fresh surface area calcinated at 600 ℃,aged surface area after 1000 ℃ and OSC at 500 ℃ of cerium zirconium mixed oxides were determined to be 89.337,34.784 m2/g,and 567 μmol O2/g for MHC method and 122.010,46.307 m2/g,and 665 μmol O2/g for AAHC method,respectively.

  7. Side Stream Filtration for Cooling Towers

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-10-20

    This technology evaluation assesses side stream filtration options for cooling towers, with an objective to assess key attributes that optimize energy and water savings along with providing information on specific technology and implementation options. This information can be used to assist Federal sites to determine which options may be most appropriate for their applications. This evaluation provides an overview of the characterization of side stream filtration technology, describes typical applications, and details specific types of filtration technology.

  8. Glomerular Filtration Barrier Assembly: An insight

    OpenAIRE

    Arif, Ehtesham; Nihalani, Deepak

    2013-01-01

    A glomerulus is the network of capillaries that resides in the Bowman’s capsule that functions as a filtration unit of kidney. The glomerular function ensures that essential plasma proteins are retained in blood and the filtrate is passed on as urine. The glomerular filtration assembly is composed of three main cellular barriers that are critical for the ultrafiltration process, the fenestrated endothelium, glomerular basement membrane and highly specialized podocytes. The podocytes along wit...

  9. Uranium co-precipitation with iron oxide minerals

    Science.gov (United States)

    Duff, Martine C.; Coughlin, Jessica Urbanik; Hunter, Douglas B.

    2002-10-01

    In oxidizing environments, the toxic and radioactive element uranium (U) is most soluble and mobile in the hexavalent oxidation state. Sorption of U(VI) on Fe-oxides minerals (such as hematite [α-Fe 2O 3] and goethite [α-FeOOH]) and occlusion of U(VI) by Fe-oxide coatings are processes that can retard U transport in environments. In aged U-contaminated geologic materials, the transport and the biological availability of U toward reduction may be limited by coprecipitation with Fe-oxide minerals. These processes also affect the biological availability of U(VI) species toward reduction and precipitation as the less soluble U(IV) species by metal-reducing bacteria. To examine the dynamics of interactions between U(VI) and Fe oxides during crystallization, Fe-oxide phases (containing 0.5 to 5.4 mol% U/(U + Fe)) were synthesized by means of solutions of U(VI) and Fe(III). Wet chemical (digestions and chemical extractions) and spectroscopic techniques were used to characterize the synthesized Fe oxide coprecipitates after rinsing in deionized water. Leaching the high mol% U solids with concentrated carbonate solution (for sorbed and solid-phase U(VI) species) typically removed most of the U, leaving, on average, about 0.6 mol% U. Oxalate leaching of solids with low mol% U contents (about 1 mol% U or less) indicated that almost all of the Fe in these solids was crystalline and that most of the U was associated with these crystalline Fe oxides. X-ray diffraction and Fourier-transform infrared (FT-IR) spectroscopic studies indicate that hematite formation is preferred over that of goethite when the amount of U in the Fe-oxides exceeds 1 mol% U (˜4 wt% U). FT-IR and room temperature continuous wave luminescence spectroscopic studies with unleached U/Fe solids indicate a relationship between the mol% U in the Fe oxide and the intensity or existence of the spectra features that can be assigned to UO 22+ species (such as the IR asymmetric υ 3 stretch for O = U = O for

  10. Catalytic combustion of ethyl acetate over CeMnOx and CeMnZrOx compounds synthesized by coprecipitation method

    Institute of Scientific and Technical Information of China (English)

    Xiaoshuang Li; Jianli Wang; Chuanwen Liao; Hongyan Cao; Yaoqiang Chen; Maochu Gong

    2011-01-01

    Ce0.6Mn0.4O2 catalysts with different sources of manganese and Ce0.6-xZrxMn0.4O2 mixed oxide catalysts were prepared by coprecipitation method and were characterized by N2 adsorption-desorption,TPR,XRD,and XPS techniques.The activities of the prepared catalysts for ethyl acetate combustion,and the effects of calcination temperature and space velocity on catalytic activity were investigated.The results showed that partial replacement of Mn(NO3)2 with KMnO4 as sources of manganese could improve activities of catalysts.Ceo.45Zro.15Mno.4O2 catalyst exhibited the best catalytic activity and high thermal stability,e.g.,T90 could be still below 210 ℃ even if space velocity was up to 20000 h-1.

  11. High energy milling of zirconia-titania powders synthesized by coprecipitation; Moagem de alta energia em pos de zirconia-titania sintetizados por co-precipitacao

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cristiano M.B.; Marchi, Juliana; Lazar, Dolores R.R.; Ussui, Valter, E-mail: vussui@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    Zirconia based ceramics are known by its remarkable mechanical properties as hardness and fracture toughness and in biomedical applications are classified as bioinert. By its turn, titania ceramics has been studied due to its ability to bond directly to bone tissue, but are structurally brittle. Properties of ceramics are strongly dependent of physical and chemical characteristics of its former powders. In the present work, research done for the synthesis of zirconia-titania ceramics by the coprecipitation route are presented, emphasizing the conditioning process through a high energy milling in a atritor mill, classifying of powders in vibratory sieves and forming of cylindrical ceramic samples followed by a sintering process at 1500 deg C for 01 hour. The intermediary samples produced in the various steps of the process were characterized by scanning electronic microscope, X-ray diffraction, nitrogen gas adsorption and granulometric analysis. (author)

  12. Structural and magnetic properties of nano-sized NiCuZn ferrites synthesized by co-precipitation method with ultrasound irradiation

    Science.gov (United States)

    Harzali, Hassen; Saida, Fairouz; Marzouki, Arij; Megriche, Adel; Baillon, Fabien; Espitalier, Fabienne; Mgaidi, Arbi

    2016-12-01

    Sonochemically assisted co-precipitation has been used to prepare nano-sized Ni-Cu-Zn-ferrite powders. A suspension of constituent hydroxides was ultrasonically irradiated for various times at different temperatures with high intensity ultrasound radiation using a direct immersion titanium horn. Structural and magnetic properties were investigated using X-diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), Nitrogen adsorption at 77 K (BET) and Vibrating sample magnetometer (VSM). Preliminary experimental results relative to optimal parameters showed that reaction time t=2 h, temperature θ=90 °C and dissipated Power Pdiss=46.27 W. At these conditions, this work shows the formation of nanocrystalline single-phase structure with particle size 10-25 nm. Also, ours magnetic measurements proved that the sonochemistry method has a great influence on enhancing the magnetic properties of the ferrite.

  13. Persistent homology in graph power filtrations.

    Science.gov (United States)

    Parks, Allen D; Marchette, David J

    2016-10-01

    The persistence of homological features in simplicial complex representations of big datasets in R (n) resulting from Vietoris-Rips or Čech filtrations is commonly used to probe the topological structure of such datasets. In this paper, the notion of homological persistence in simplicial complexes obtained from power filtrations of graphs is introduced. Specifically, the rth complex, r ≥ 1, in such a power filtration is the clique complex of the rth power G(r) of a simple graph G. Because the graph distance in G is the relevant proximity parameter, unlike a Euclidean filtration of a dataset where regional scale differences can be an issue, persistence in power filtrations provides a scale-free insight into the topology of G. It is shown that for a power filtration of G, the girth of G defines an r range over which the homology of the complexes in the filtration are guaranteed to persist in all dimensions. The role of chordal graphs as trivial homology delimiters in power filtrations is also discussed and the related notions of 'persistent triviality', 'transient noise' and 'persistent periodicity' in power filtrations are introduced.

  14. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air....... These contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future....

  15. Filtration and compression of organic materials

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Keiding, Kristian

    The conventional filtration theory has been based on filtrations of incompressible particles such as anatase, kaolin and clay. The filtration models have later been used for organic slurries but can often not explain the observed experimental data. At constant pressure, the filtrate volume does...... not increase in proportion with square root time when e.g. sewage sludge and manure are filtered. Different explanations have been suggested. However, organic slurries are complex mixtures and it is therefore difficult to evaluate the suggested explanations and develops new models. One possible solution...

  16. Adsorption Rate Models for Multicomponent Adsorption Systems

    Institute of Scientific and Technical Information of China (English)

    姚春才

    2004-01-01

    Three adsorption rate models are derived for multicomponent adsorption systems under either pore diffusion or surface diffusion control. The linear driving force (LDF) model is obtained by assuming a parabolic intraparticle concentration profile. Models I and Ⅱ are obtained from the parabolic concentration layer approximation. Examples are presented to demonstrate the usage and accuracy of these models. It is shown that Model I is suitable for batch adsorption calculations and Model Ⅱ provides a good approximation in fixed-bed adsorption processes while the LDF model should not be used in batch adsorption and may be considered acceptable in fixed-bed adsorption where the parameter Ti is relatively large.

  17. Physical stability and enthalpy relaxation of drug-hydroxypropyl methylcellulose phthalate solvent change co-precipitates.

    Science.gov (United States)

    Sertsou, Gabriel; Butler, James; Hempenstall, John; Rades, Thomas

    2003-01-01

    The poorly water-soluble drug GWX was co-precipitated with hydroxypropyl methylcellulose phthalate (HPMCP) using a solvent change method. The two co-precipitate formulations made, with drug-HPMCP ratios of 2:8 and 5:5, were analysed using modulated temperature differential scanning calorimetry. They were found to consist of completely amorphous solid solution and a mixture of amorphous solid solution, crystalline drug and amorphous drug, respectively. Stability with respect to crystallization of the two co-precipitates and pure amorphous drug made by quench cooling was compared by storing preparations at 25 degrees C and 40 degrees C, under vacuum over P(2)O(5), and at 75% relative humidity (r.h.). Humidity (75% r.h. compared with dry) had a larger influence on crystallization of the amorphous drug than temperature (25 degrees C compared with 40 degrees C). The solid solution phase in co-precipitates had a relatively higher stability than amorphous drug alone, with respect to crystallization, in presence of the plasticizer water, and crystalline drug. These findings were partly explained by evidence of decreased molecular mobility in the amorphous solid solution with respect to amorphous drug alone, using enthalpy relaxation measurements. At an ageing temperature of 65 degrees C, the calculated half-life for enthalpy relaxation of the 2:8 drug-HPMCP ratio coprecipitate was about 6 orders of magnitude greater than that of amorphous drug alone, indicating a large difference in relative molecular mobility.

  18. Adsorption and wetting.

    NARCIS (Netherlands)

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption

  19. Physicochemical characterization and adsorption behavior of Ca/Al chloride hydrotalcite-like compound towards removal of nitrate.

    Science.gov (United States)

    Islam, Mahamudur; Patel, Rajkishore

    2011-06-15

    The objective of the present research was to synthesize, characterize and to investigate adsorption of nitrate from synthetic nitrate solution by Ca-Al-Cl HTlc. In the present study Ca-Al-Cl HTlc was synthesized by co-precipitation method and was characterized using SEM, XRD, FTIR and TGA-DSC. To assess the practical usefulness, a detailed removal study of nitrate was carried out. The removal of nitrate was 84.6% under neutral condition using 0.35 g of adsorbent in 100mL of nitrate solution having initial concentration of 10mg/L. Adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to linearly transformed Langmuir adsorption isotherm with R(2) (correlation coefficient)>0.99. Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. In order to understand the adsorption type, equilibrium data were tested with Dubinin-Radushkevich isotherm.

  20. Tangential flow filtration of hemoglobin.

    Science.gov (United States)

    Palmer, Andre F; Sun, Guoyong; Harris, David R

    2009-01-01

    Bovine and human hemoglobin (bHb and hHb, respectively) was purified from bovine and human red blood cells via tangential flow filtration (TFF) in four successive stages. TFF is a fast and simple method to purify Hb from RBCs using filtration through hollow fiber (HF) membranes. Most of the Hb was retained in stage III (100 kDa HF membrane) and displayed methemoglobin levels less than 1%, yielding final concentrations of 318 and 300 mg/mL for bHb and hHb, respectively. Purified Hb exhibited much lower endotoxin levels than their respective RBCs. The purity of Hb was initially assessed via SDS-PAGE, and showed tiny impurity bands for the stage III retentate. The oxygen affinity (P(50)) and cooperativity coefficient (n) were regressed from the measured oxygen-RBC/Hb equilibrium curves of RBCs and purified Hb. These results suggest that TFF yielded oxygen affinities of bHb and hHb that are comparable to values in the literature. LC-MS was used to measure the molecular weight of the alpha (alpha) and beta (beta) globin chains of purified Hb. No impurity peaks were present in the HPLC chromatograms of purified Hb. The mass of the molecular ions corresponding to the alpha and beta globin chains agreed well with the calculated theoretical mass of the alpha- and beta- globin chains. Taken together, our results demonstrate that HPLC-grade Hb can be generated via TFF. In general, this method can be more broadly applied to purify Hb from any source of RBCs. This work is significant, since it outlines a simple method for generating Hb for synthesis and/or formulation of Hb-based oxygen carriers.

  1. A nanoscale co-precipitation approach for property enhancement of Fe-base alloys.

    Science.gov (United States)

    Zhang, Zhongwu; Liu, Chain Tsuan; Miller, Michael K; Wang, Xun-Li; Wen, Yuren; Fujita, Takeshi; Hirata, Akihiko; Chen, Mingwei; Chen, Guang; Chin, Bryan A

    2013-01-01

    Precipitate size and number density are two key factors for tailoring the mechanical behavior of nanoscale precipitate-hardened alloys. However, during thermal aging, the precipitate size and number density change, leading to either poor strength or high strength but significantly reduced ductility. Here we demonstrate, by producing nanoscale co-precipitates in composition-optimized multicomponent precipitation-hardened alloys, a unique approach to improve the stability of the alloy against thermal aging and hence the mechanical properties. Our study provides compelling experimental evidence that these nanoscale co-precipitates consist of a Cu-enriched bcc core partially encased by a B2-ordered Ni(Mn, Al) phase. This co-precipitate provides a more complex obstacle for dislocation movement due to atomic ordering together with interphases, resulting in a high yield strength alloy without sacrificing alloy ductility.

  2. Strontium Co-precipitation During Biomineralization of Calcite in Porous Media Using Differing Treatment Strategies

    Science.gov (United States)

    Lauchnor, E. G.; Schultz, L.; Mitchell, A.; Cunningham, A. B.; Gerlach, R.

    2013-12-01

    The process of ureolytically-induced calcium carbonate mineralization has been shown in laboratory studies to be effective in co-precipitation of heavy metals and radionuclides. During this process, the microbially catalyzed hydrolysis of urea increases alkalinity and pH, thus promoting CaCO3 precipitation in the presence of dissolved calcium. One proposed application of biomineralization includes the remediation of radionuclides such as strontium, which can be co-precipitated in situ within calcite. Strontium is of concern at several US DOE sites where it is a radioactive product of uranium fission and groundwater contaminant. Our research focuses on promoting attached bacteria, or biofilms, in subsurface environments where they serve as immobilized catalysts in biomineralization and can aide in co-precipitation of some contaminants. In this work, flat plate reactors with 1 mm etched flow channels designed to mimic a porous medium environment were used. Reactors were inoculated with the model ureolytic bacterium Sporosarcina pasteurii and addition of urea, calcium and strontium containing fluid was performed to induce biomineralization. Continuous flow and stopped-flow injection strategies were investigated to evaluate differences in strontium co-precipitation efficiency. During stopped-flow experiments, injection of cementation fluid containing urea, Ca2+ and Sr2+ was alternated with growth nutrients for stimulation of microbial activity. Control parameters such as urea and calcium concentration and injection flow rate are currently being varied to optimize rate and efficiency of strontium co-precipitation. Ureolytically induced calcite precipitation and strontium incorporation in the calcite was verified by chemical and mineralogical analyses, including X-ray diffraction and ICP-MS. Strontium co-precipitation efficiency was similar under different injection strategies. Alternating calcium-containing fluid with growth nutrients allowed for continued viability of

  3. Turbidity removal: Gravel and charcoal as roughing filtration media

    Directory of Open Access Journals (Sweden)

    Josiah A. Adeyemo

    2010-10-01

    Full Text Available Roughing filtration is an important pre-treatment process for wastewater, because it efficiently separates fine solid particles over prolonged periods, without the addition of chemicals. For this study, a pilot plant was designed at Delmas Coal Mine in the Mpumalanga province of South Africa. The design and sizing of the pilot plant was guided by Wegelin’s design criteria. Gravel was used as a control medium because it is one of the most commonly used roughing filter media and because it was used in developing the criteria. We compared the performance of gravel as a filter medium to that of another locally available material, charcoal, for the removal of turbidity in wastewater. The pilot plant was monitored continuously for 90 days from commissioning until the end of the project. The overall performance of the roughing filter in turbidity removal, using gravel or charcoal, was considered efficient for the pre-treatment of waste water. Charcoal performed slightly better than gravel as a filter medium for the removal of turbidity, possibly because charcoal has a slightly higher specific surface area and porosity than gravel, which could enhance sedimentation and other filtration processes, such as adsorption, respectively.

  4. Hierarchically structured polysulfone/titania fibrous membranes with enhanced air filtration performance.

    Science.gov (United States)

    Wan, Huigao; Wang, Na; Yang, Jianmao; Si, Yinsong; Chen, Kun; Ding, Bin; Sun, Gang; El-Newehy, Mohamed; Al-Deyab, Salem S; Yu, Jianyong

    2014-03-01

    Hierarchically structured, superhydrophobic filter medium exhibiting robust filtration performance to airborne particulate were prepared by a facile deposition of electrospun polysulfone/titania nanoparticles (PSU/TiO2 NPs) on a conventional nonwoven substrate. The air permeability, tensile strength and abrasion resistance of pristine PSU fibrous membranes could be finely controlled by regulating the solvent composition and number ratios of jets. By employing the TiO2 NPs incorporation, the pristine PSU fibers were endowed with promising superhydrophobicity with a water contact angle of up to 152°. The quantitative hierarchical roughness analysis using N2 adsorption method has confirmed the major contribution of TiO2 NPs on enhancing the porous structure and surface fractal features with irregular rough structure. Filtration performance studies have revealed that the filtration efficiency and pressure drop of resultant hybrid membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. Furthermore, the as-prepared PSU/TiO2-5 membrane exhibited improved filtration efficiency (99.997%) and pressure drop (45.3 Pa) compared with pristine PSU membrane, which would make them a promising media for fine particle filtration, and a new insight was also provided into the design and development of high performance filter medium based on hierarchical structured fibers.

  5. Particle contamination of parenteralia and in-line filtration of proteinaceous drugs.

    Science.gov (United States)

    Werner, Benjamin Patrick; Winter, Gerhard

    2015-12-30

    Protein drug products play an important role in the treatment of severe diseases. However, due to the instability of these complex molecules, protein aggregates can form which can compromise drug safety and efficacy including immunogenic reactions. In-line filtration during the administration of these drugs can serve as a final safeguarding step to protect patients from risks associated with proteinaceous particles. A unique analysis of more than 300 marketed protein drug products revealed that already around 16% of all these products are filtered during preparation or administration. Further, the research revealed that no standardized filtration practice exists. Broad variances regarding filter membrane or pore size are found and sometimes no specifications are mentioned at all. The benefits as well as possible negative impacts of filtration like filter shedding, extractables or drug adsorption are critically assessed. Several proposals to improve the current filtration practice and to expand the number of in-line filtered protein drug products are made. The suggestions include the demand for the specific usage of one filter membrane type, the establishment of a filtration routine for unfiltered protein drugs and a statistical analysis between filtered and non-filtered products with similar formulations to identify possible differences in the immunogenicity rate.

  6. 丙烯酸接枝改性聚丙烯非织造布及其对染料过滤吸附与解吸作用的研究%Photo-grafting modification of polypropylene nonwovens with acrylic acid and its filtration adsorption and desorption toward cationic dye

    Institute of Scientific and Technical Information of China (English)

    艾丽; 刘颖; 王宇阳; 石小丽; 朱新生

    2014-01-01

    采用紫外照射方法对聚丙烯( PP)非织造布进行改性。将丙烯酸( AA)接枝聚合到PP非织造布表面,制得PP-g-AA改性非织造布。研究了交联剂浓度对接枝率的影响,并研究了接枝前后非织造布的形态和微观结构的变化,以及接枝非织造布对染液的吸附与解吸行为及其透水性。结果表明:AA可有效接枝到PP非织造布上;接枝非织造布对阳离子红X-GRL的最大吸附量为146.4 mg/g,显示出优异的吸附性能;等温吸附符合Freundlich模型,吸附动力学模型符合Lagegren准二级动力学方程;接枝非织造布的水通量表现出强烈的酸碱性和电解质依赖性;接枝PP非织造布对阳离子染料的吸附能再生循环利用。采用吸附过滤方式使用PP-g-AA非织造布可对印染废水进行深度处理。%Poly( acrylic acid) was grafted onto the polypropylene nonwovens surfaces under ultraviolet irradiation . PP-g-AA nonwovens was made by grafting poly (acrylic acid) (PAA) on the surface of PP.The effect of crosslinking agent on the grafting degree , as well as the microstructure of the grafted nonwovens and ungrafted nonwovens , the adsorption , desorption and water permeability of the grafted nonwovens were carefully investigated .The results indicated that , poly ( acrylic acid ) was enwrapped evenly on the fiber surfaces.The maximum equilibrium adsorption capacity of the cationic dye was up to 146.4 mg/g in this experimental setup , indicating the excellent adsorption performance .The absorption isotherm of the grafted nonwovens follows Freundlich model .The dynamic adsorption process is in accordance with the Lagergren’s pseudo-second order model .The water permeability strongly was depended on acidity and the ionic strength of electrolyte solution .The results of the repeating adsorption and desorption recycles implies reusability , and applicability for deeply treating the dyeing and printing wastewaters .

  7. Filtrating forms of soil bacteria

    Science.gov (United States)

    Van'kova, A. A.; Ivanov, P. I.; Emtsev, V. T.

    2013-03-01

    Filtrating (ultramicroscopic) forms (FF) of bacteria were studied in a soddy-podzolic soil and the root zone of alfalfa plants as part of populations of the most widespread physiological groups of soil bacteria. FF were obtained by filtering soil solutions through membrane filters with a pore diameter of 0.22 μm. It was established that the greater part of the bacteria in the soil and in the root zone of the plants has an ultramicroscopic size: the average diameter of the cells is 0.3 μm, and their length is 0.6 μm, which is significantly less than the cell size of banal bacteria. The number of FF varies within a wide range depending on the physicochemical conditions of the habitat. The FF number's dynamics in the soil is of a seasonal nature; i.e., the number of bacteria found increases in the summer and fall and decreases in the winter-spring period. In the rhizosphere of the alfalfa, over the vegetation period, the number of FF and their fraction in the total mass of the bacteria increase. A reverse tendency is observed in the rhizoplane. The morphological particularities (identified by an electron microscopy) and the nature of the FF indicate their physiological activity.

  8. PDF-based heterogeneous multiscale filtration model.

    Science.gov (United States)

    Gong, Jian; Rutland, Christopher J

    2015-04-21

    Motivated by modeling of gasoline particulate filters (GPFs), a probability density function (PDF) based heterogeneous multiscale filtration (HMF) model is developed to calculate filtration efficiency of clean particulate filters. A new methodology based on statistical theory and classic filtration theory is developed in the HMF model. Based on the analysis of experimental porosimetry data, a pore size probability density function is introduced to represent heterogeneity and multiscale characteristics of the porous wall. The filtration efficiency of a filter can be calculated as the sum of the contributions of individual collectors. The resulting HMF model overcomes the limitations of classic mean filtration models which rely on tuning of the mean collector size. Sensitivity analysis shows that the HMF model recovers the classical mean model when the pore size variance is very small. The HMF model is validated by fundamental filtration experimental data from different scales of filter samples. The model shows a good agreement with experimental data at various operating conditions. The effects of the microstructure of filters on filtration efficiency as well as the most penetrating particle size are correctly predicted by the model.

  9. [Removal of Sulfate Ions from Aqueous Solution by Adsorption with Hydrotalcite- like Composite].

    Science.gov (United States)

    Gu, Yi-bing; Ma, Yong-wen; Wan, Jin-quan; Wang, Yan; Guan, Ze-yu

    2016-03-15

    Hydrotalcite-like composite synthesized by co-precipitation method was used as an adsorbent to remove the sulfate ions in aqueous solution. XRD, FT-IR , SEM and EDS elemental analysis were used to clarify the structure and composition of the hydrotalcite- like composite. The influences of time, initial pH value and coexisting ions on adsorption performance were investigated. The result showed the material was the composite of zinc aluminum nitrate hydrotalcite-like compounds and zinc aluminum phenylalanine hydrotalcite-like compounds. Hydrotalcite-like composite had a good performance in adsorption of sulfate ions, and the maximum adsorption capacity was 52.75 mg · g⁻¹. The data fitted pseudo-second order kinetic model best, which indicated that chemical adsorption was the rate-limiting step. Freundlich isotherm was more suitable to describe the adsorption process, and this meant the adsorption of sulfate ions by hydrotalcite-like composite was multilayered adsorption. Thermodynamic parameters showed that the adsorption process was endothermic and spontaneous at room temperature. Hydrotalcite-like composite adsorbed sulfate ions mainly through ion exchange, electrostatic force and physical adsorption. The experimental results showed that the hydrotalcite-like composite had potential for sulfate ion removal in the aqueous solution.

  10. Y-TZP ceramic processing from coprecipitated powders : A comparative study with three commercial dental ceramics

    NARCIS (Netherlands)

    Lazar, Dolores R. R.; Bottino, Marco C.; Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Ussui, Valter; Bressiani, Ana H. A.

    2008-01-01

    Objectives. (1) To synthesize 3 mol% yttria-stabilized zirconia (3Y-TZP) powders via coprecipitation route, (2) to obtain zirconia ceramic specimens, analyze surface characteristics, and mechanical properties, and (3) to compare the processed material with three reinforced dental ceramics. Methods.

  11. RATES OF HYDROUS FERRIC OXIDE CRYSTALLIZATION AND THE INFLUENCE ON COPRECIPITATED ARSENATE

    Science.gov (United States)

    Arsenate coprecipitated with hydrous ferric oxide (HFO) was stabilized against dissolution during transformation of HFO to more crystalline iron (hydr)oxides. The rate of arsenate stabilization approximately coincided with the rate of HFO transformation at pH 6 and 40 ?C. Compa...

  12. Trace Level Rare Earth Elements Separation From Gram Scale Uranium by Calcium Fluoride Coprecipitation

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiu-feng

    2013-01-01

    In the fission yield measurement of rare earth elements of uranium induced by neutron,and the analysis of rare earth elements in spent fuel,the separation of trace rare earth elements from a large number of uranium has very important significance.We separated trace level rare earth elements from gram scale uranium by calcium fluoride coprecipitation in this paper.

  13. Stabilization of microbial residues by co-precipitation with Fe and Al oxides

    Science.gov (United States)

    Miltner, Anja; Achtenhagen, Jan; Kästner, Matthias

    2016-04-01

    Recent studies have shown that microbial residues contribute significantly to soil organic matter (SOM) formation. This material, however, is readily degradable and thus needs to be stabilized in soil. We hypothesize that the interaction with minerals, in particular co-precipitation with metal oxyhydroxides, plays an important role in stabilization of cell envelope material. We therefore analyzed the mineralization of 14C-labelled Escherichia coli cells and cell envelope fragments during incubation of the cell materials alone or after co-precipitation with either Fe or Al oxyhydroxide. We also tested the effect of environmental conditions, in particular oxygen supply and redox potential, on the stabilizing effect of the mineral phases. Co-precipitation with both Fe and Al oxyhydroxides decreased the mineralization significantly, indicating strong protection of biomass and biomass-derived fragments. Surprisingly, the mineralization of intact cells was higher than that of cell envelope fragments. This points to a higher recalcitrance of the cell envelope fragments, which therefore may be selectively enriched in SOM. Reductive conditions obtained after water-logging combined with excessive supply of an easily available carbon source resulted in increased mineralization in the treatments containing Fe oxyhydroxides, due to reductive dissolution of the Fe oxyhydroxide and thus loss of the stabilizing agent. We therefore conclude that co-precipitation with and incrustation by Fe or Al oxyhydroxides is a relevant stabilization mechanism for microbial residues. The same mechanism also may apply for SOM in general.

  14. Y-TZP ceramic processing from coprecipitated powders : A comparative study with three commercial dental ceramics

    NARCIS (Netherlands)

    Lazar, Dolores R. R.; Bottino, Marco C.; Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Ussui, Valter; Bressiani, Ana H. A.

    2008-01-01

    Objectives. (1) To synthesize 3 mol% yttria-stabilized zirconia (3Y-TZP) powders via coprecipitation route, (2) to obtain zirconia ceramic specimens, analyze surface characteristics, and mechanical properties, and (3) to compare the processed material with three reinforced dental ceramics. Methods.

  15. Adsorptional photocatalytic degradation of methylene blue onto pectin-CuS nanocomposite under solar light.

    Science.gov (United States)

    Gupta, Vinod Kumar; Pathania, Deepak; Agarwal, Shilpi; Singh, Pardeep

    2012-12-01

    This study describes the effect of adsorption on methylene blue degradation using pectin-CuS nanocomposite (PCSNC). The nanocomposite was synthesized using co-precipitation methods followed by direct encapsulation with pectin. The synthesized nanocomposite was characterized by SEM, TEM, XRD, FTIR and UV-vis spectral technique. The adsorption and photocatalytic efficiencies of PCSNC were compared with copper sulphide nanoparticle (CSNP). The dye removal was studied under different reaction conditions. The adsorption capacity of pectin based nanocomposite was higher due to other free functional group on pectin surface after connecting to nanoparticles. The simultaneous adsorption and photodegradation process (A+P) was the most efficient process due to rapid destruction of adsorbed dye molecules. The complete COD removal was attained in 10h using PCSNC/A+P process. On comparing with CSNP, pectin-CuS nano composite showed more degradation efficiency and reusability for MB degradation.

  16. Adsorption of Disperse Blue SBL dye by synthesized poorly crystalline hydroxyapatite

    Institute of Scientific and Technical Information of China (English)

    BARKA Noureddine; QOURZAL Samir; ASSABBANE Ali; NOUNAH Abederrahman; A(I)T-ICHOU Yhya

    2008-01-01

    The present study has been undertaken to evaluate the adsorption in batch mode of a disperse dye (Disperse Blue SBL) by poorlycrystalline hydroxyapatite synthesized by coprecipitation between Ca(NO3)2 and (NH4)2HPO4 reagents in aqueous solution at roomtemperature. The adsorption experiments were carried out to investigate the factors that influence the dye uptake by the adsorbent, suchas the contact time under agitation, adsorbent dosage, initial dye concentration, solution temperature, and pH. The experimental resultsshow that the percentage of dye removal increases with increasing the amount of adsorbent, until the total discoloration. The adsorptionisotherms follow the model of Langmuir with a high adsorption capacity. The adsorption was pH and temperature dependent.

  17. [Preparation and characterization of zirconium hydroxide powder for fluoride adsorption].

    Science.gov (United States)

    Yang, Shuo; Dou, Xiao-min; Liang, Wen-yan; Wang, Yi-li; Lin, Wei

    2010-07-01

    The method co-precipitation was applied to preparation the zirconium hydroxide as a type drinking-water defluoridation adsorbent. The effect of the preparation conditions on the adsorptive capacity was studied. The optimization of preparation condition for zirconium hydroxide concludes that co-precipitation time is 10 h, pH value is 7.0, drying time is 72 h, calcination temperature is below 100 degrees C. Also, the adsorbent samples were characterized. SEM measurements reveal that zirconium hydroxide powder are constructed by several small particles, with a diameter about 20-30 microm. XRD and TG/DTA measurements show that the zirconium hydroxide samples have amorphous phase and converse to tetragonal phase when calcined at 600 degrees C. Nitrogen adsorption/desorption measurements show that samples have large surface areas of 138.4 m2/g and a 2 nm average pore size distribution in the mesopore region. The performance of zirconium hydroxide regeneration process was investigated. The results show that the regeneration techniques are very suitable to restore the fluorine-removal ability for zirconium hydroxide.

  18. Metal reduction at bulk chemical filtration

    Science.gov (United States)

    Umeda, Toru; Daikoku, Shusaku; Tsuzuki, Shuichi; Murakami, Tetsuya

    2017-03-01

    OK73 thinner and cyclohexanone, both of which were spiked with metals were passed through Nylon 6,6 filter, varying flow rate, which include the conditions of both point-of-use and bulk filtrations. The influent and effluent metal concentrations were measured using ICP-MS for metal removal efficiency of the filtration. As a result, removal efficiency for some metals descended depending on the flow rate, while others maintained. Slower flow rate is recommended to maintain low metal concentration in bulk filtration based on the result. Metals in cyclohexanone were reduced at higher efficiency than in OK73 thinner, agrees with a metal removal model of hydrophilic adsorbent in organic solvent, evidenced in our previous paper. Further, metal reduction on 300 mm φ Si wafer after coating organic solvents with Nylon 6,6 filtration was evidenced with TREX analysis.

  19. Filtration in coal liquefaction - Influence of filtration conditions in non-hydrogenated systems

    Science.gov (United States)

    Clarke, J. W.; Rantell, T. D.

    1980-01-01

    A series of experiments has been carried out to study the effects of filtration conditions upon the rate of filtration of non-hydrogenated coal digests. The results show the dependence of cake resistivity on both the filtration temperature and pressure. Filter cakes were found to be compressible, resulting in smaller increases in rate with increasing pressure than with incompressible cakes. The filtration temperature determines the packing of residual solids in the cake which in turn affects the cake resistivity. An empirical relation has been derived between filtration temperature and resistivity. With increasing temperature there is an increase in filtration rate due to the reduced viscosity, but a reduction owing to a higher packing density of solids in the filter cake.

  20. Complications and Management of the Filtration Bleb

    Institute of Scientific and Technical Information of China (English)

    Clement; W; N; Chan

    1992-01-01

    Filtration surgery is the commonest operation performed for closed angle or open angle glaucoma when medical treatment or laser trabeculoplasty has failed to control the intraocular pressure. It is characterized by the formation of an artificial drainage fistula between the anterior chamber and subconjunctival space. The successful operation is evidenced by the appearance of a subconjunctival filtration bleb which in turn depends on the patency of this pathway. Despite numerous modification, the procedu...

  1. The Glomerular Filtration Barrier: Components and Crosstalk

    OpenAIRE

    Madhav C. Menon; Chuang, Peter Y.; Cijiang John He

    2012-01-01

    The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents—the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte). Understanding the pathomechanisms of inherited and acquired human diseases as well...

  2. Properties of the filtrate from treatment of pig manure by filtration method

    Directory of Open Access Journals (Sweden)

    Makara Agnieszka

    2017-02-01

    Full Text Available This paper presents properties of filtrate obtained from pig manure using the AMAK treatment process, which includes the mineralization of macro- and microfertilizer components by the hydrolyzing of organic matter into forms that are bioavailable to plants. Filtration produced two products, sediment and filtrate. The quality of the filtrate allowed for its use as a substitute of water to irrigate crops. Concentrations of heavy metals are very low and therefore the quality of the filtrate fully complies with European standard concerning fertilizers. The used mineralization process practically eliminated odors from the filtrate. The reduction of specific odor emission by 99.1-99.5% in samples taken from above the filtrate, respectively compared to the odor concentration found in samples taken from above raw pig manure. Sediment could be used as raw material for production of mineral-organic fertilizer. Filtrate and filtration sediments analyses show that the majority of nitrogen and other fertilizing compounds included in raw pig manure remains in sediment.

  3. Chitosan-kaolin coprecipitate as disintegrant in microcrystalline cellulose-based pellets elaborated by extrusion-spheronization.

    Science.gov (United States)

    Goyanes, Alvaro; Souto, Consuelo; Martínez-Pacheco, Ramón

    2013-02-01

    The usefulness of a coprecipitate of chitosan and kaolin as disintegrant in the pellets of microcrystalline cellulose (MCC) and hydrochlorothiazide (HCT) (as a model of poorly water-soluble drug) produced by extrusion-spheronization was evaluated in this study. The effectiveness of chitosan-kaolin coprecipitate to increase the dissolution rate was compared with that of kaolin and chitosan. A possible synergy effect was also evaluated between the coprecipitate, kaolin or chitosan and sorbitol, added to the pellets as a very water-soluble diluent. The chitosan-kaolin coprecipitate, the kaolin or the chitosan allowed pellets to be obtained of adequate size, roundness, mechanical strength and flow properties. Furthermore, the incorporation of chitosan-kaolin coprecipitate or chitosan significantly increased the dissolution rate of HCT independently of the sorbitol content. The effects on the dissolution of HCT derived from the incorporation of coprecipitate to the pellets can be attributed to its content of chitosan. However, the addition of kaolin into the pellets did not significantly affect the HCT dissolution process. The pellets incorporating coprecipitated chitosan-kaolin or chitosan and the maximum proportion of sorbitol (50%) led to the highest HCT dissolution rate and experienced a rapid and complete disintegration in the dissolution medium.

  4. Cu Binding to Iron Oxide-Organic Matter Coprecipitates in Solid and Dissolved Phases

    Science.gov (United States)

    Vadas, T. M.; Koenigsmark, F.

    2015-12-01

    Recent studies indicate that Cu is released from wetlands following storm events. Assymetrical field flow field fractionation (AF4) analyses as well as total and dissolved metal concentration measurements suggest iron oxide-organic matter complexes control Cu retention and release. Coprecipitation products of Fe oxide and organic matter were prepared under conditions similar to the wetland to assess Cu partitioning to and availability from solid phases that settle from solution as well as phases remaining suspended. Cu coprecipitation and sorption to organomineral precipitation solids formed at different Fe:organic carbon (OC) ratios were compared for net Cu removal and extractability. As more humic acid was present during precipitation of Fe, TEM images indicated smaller Fe oxide particles formed within an organic matrix as expected. In coprecipitation reactions, as the ratio of Fe:OC decreased, more Cu was removed from solution at pH 5.5 and below. However, in sorption reactions, there was an inhibition of Cu removal at low OC concentrations. As the pH increased from 5.5 to 7 and as solution phase OC concentration increased, more Cu remained dissolved in both coprecipitation and sorption reactions. The addition of Ca2+, glycine, histidine and citric acid or lowering the pH resulted in more extractable Cu from the coprecipitation compared with the sorption reactions. The variations in Cu extraction were likely due to a combination of a more amorphous structure in CPT products, and the relative abundance of available Fe oxide or OC binding sites. Suspended Fe oxide-organic matter coprecipitates were assessed using AF4 coupled to online TOC analysis and ICP-MS. In laboratory prepared samples, Cu was observed in a mixture of small 1-5 nm colloids of Fe oxide-organic matter precipitates, but the majority was observed in larger organic matter colloids and were not UV absorbing, suggesting more aliphatic carbon materials. In field samples, up to 60% of the dissolved Cu

  5. 21 CFR 177.2910 - Ultra-filtration membranes.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ultra-filtration membranes. 177.2910 Section 177... Components of Articles Intended for Repeated Use § 177.2910 Ultra-filtration membranes. Ultra-filtration... the processing of food, under the following prescribed conditions; (a)(1) Ultra-filtration...

  6. Preparation of tetragonal CaO-ZrO2 nano-powder by chemical coprecipitation method

    Institute of Scientific and Technical Information of China (English)

    刘建本; 阮建明; 邹俭鹏; 李亚军; 骆锋

    2003-01-01

    With zirconium oxychloride, nitrate of lime and ammonia as raw materials, nano-powder of CaO-ZrO2 was prepared by chemical coprecipitation method. By use of azeotropic distillation processing, chemical coprecipitation precursor was obtained. Phase transformation of the precursor was observed at the temperature of 593.81 ℃ and 1 234.56 ℃ respectively with DTA analyses. Phase structure was analyzed through XRD and Raman spectra. The average particle size of tetragonal zirconium oxide powder was 9.8 and 43.7 nm after calcination at 600 and 1 100 ℃ respectively which was tested by TEM and BET analyses. Furthermore, the influences of the doping of nitrate of lime and the average particle size of zirconium oxide on the stability of tetragonal zirconium oxide were also discussed.

  7. Synthesis of alumina/YAG 20 vol% composite by co-precipitation

    Directory of Open Access Journals (Sweden)

    Radosław Lach

    2011-12-01

    Full Text Available Co-precipitation of alumina/YAG precursor from aluminum and yttrium nitrate solution with ammonium carbonate results in dawsonite. Its crystallographic parameters differ from the compound precipitated with no yttrium additive. It suggests that yttrium ions become incorporated into the dawsonite structure. The DSC/TG and X-ray diffraction measurements show decomposition of dawsonite at elevated temperatures resulting in γ-Al2O3 and then δ- and θ-alumina modifications. Full transformation to α-Al2O3 and YAG occurs at temperatures higher than 1230°C. Starting powder for the sintering experiments was prepared using the coprecipitated precursor calcined at 600°C. Seeding of such powder with 5 wt.% α-Al2O3 results in material of 98% density at 1500°C. Much lower densification show compacts of unseeded powder.

  8. Biological Chitin-MOF Composites with Hierarchical Pore Systems for Air-Filtration Applications.

    Science.gov (United States)

    Wisser, Dorothea; Wisser, Florian M; Raschke, Silvia; Klein, Nicole; Leistner, Matthias; Grothe, Julia; Brunner, Eike; Kaskel, Stefan

    2015-10-19

    Metal-organic frameworks (MOFs) are promising materials for gas-separation and air-filtration applications. However, for these applications, MOF crystallites need to be incorporated in robust and manageable support materials. We used chitin-based networks from a marine sponge as a non-toxic, biodegradable, and low-weight support material for MOF deposition. The structural properties of the material favor predominant nucleation of the MOF crystallites at the inside of the hollow fibers. This composite has a hierarchical pore system with surface areas up to 800 m(2)  g(-1) and pore volumes of 3.6 cm(3)  g(-1) , allowing good transport kinetics and a very high loading of the active material. Ammonia break-through experiments highlight the accessibility of the MOF crystallites and the adsorption potential of the composite indicating their high potential for filtration applications for toxic industrial gases.

  9. Adsorption removal of thiocyanate from aqueous solution by calcined hydrotalcite

    Institute of Scientific and Technical Information of China (English)

    LI Yu-jiang; YANG Min; ZHANG Xiao-jin; WU Tao; CAO Nan; WEI Na; BI Yan-jun; WANG Jing

    2006-01-01

    A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD,TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type.The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite (HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5-10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption ofthiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.

  10. Adsorption removal of thiocyanate from aqueous solution by calcined hydrotalcite.

    Science.gov (United States)

    Li, Yu-Jiang; Yang, Min; Zhang, Xiao-Jin; Wu, Tao; Cao, Nan; Wei, Na; Bi, Yan-Jun; Wang, Jing

    2006-01-01

    A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500 degrees C, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite (HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5-10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption of thiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.

  11. Synthesis of yttria-doped bismuth oxide powder by carbonate coprecipitation for IT-SOFC electrolyte.

    Science.gov (United States)

    Lee, J G; Kim, S H; Yoon, H H

    2011-01-01

    Yttria-doped bismuth oxide (YBO) powders were synthesized by ammonium carbonate coprecipitation for the preparation of electrolytes of an intermediate temperature solid oxide fuel cell (IT-SOFC). The starting salts were yttrium and bismuth nitrate. The crystal structures and the morphological characteristics of the particles were analyzed by XRD and SEM, respectively. The ionic conductivity of the sintered pellet was measured by an electrochemical impedance analyzer. The size of the calcined YBO powders were in the range of 20-100 nm as measured by SEM images. The YBO pellets had a face-centered cubic structure, and their crystallite size was about 54-88 nm. The ionic conductivity of the YBO pellets sintered at 800 degrees C was observed to be 2.7 x 10(-1) Scm-(-1) at 700 degrees C. The ball-milling of the YBO powder before it was pelletized was found to have been unrequired probably because of a good sinterability of the YBO powders that was prepared via the ammonium carbonate coprecipitation method. The results showed that the ammonium carbonate coprecipitation process could be used as the cost-efficient method of producing YBO electrolytes for IT-SOFC.

  12. Synthesis of layered double hydroxide nanosheets by coprecipitation using a T-type microchannel reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Xiujiang; Sun, Meiyu; Ma, Xiuming [State Key Laboratory Base of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Hou, Wanguo, E-mail: wghou@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100 (China)

    2014-02-15

    The synthesis of Mg{sub 2}Al–NO{sub 3} layered double hydroxide (LDH) nanosheets by coprecipitation using a T-type microchannel reactor is reported. Aqueous LDH nanosheet dispersions were obtained. The LDH nanosheets were characterized by X-ray diffraction, transmission electron microscopy, atomic force microscopy and particle size analysis, and the transmittance and viscosity of LDH nanosheet dispersions were examined. The two-dimensional LDH nanosheets consisted of 1–2 brucite-like layers and were stable for ca. 16 h at room temperature. In addition, the co-assembly between LDH nanosheets and dodecyl sulfate (DS) anions was carried out, and a DS intercalated LDH nanohybrid was obtained. To the best of our knowledge, this is the first report of LDH nanosheets being directly prepared in bulk aqueous solution. This simple, cheap method can provide naked LDH nanosheets in high quantities, which can be used as building blocks for functional materials. - Graphical abstract: Layered double hydroxide (LDH) nanosheets were synthesized by coprecipitation using a T-type microchannel reactor, and could be used as basic building blocks for LDH-based functional materials. Display Omitted - Highlights: • LDH nanosheets were synthesized by coprecipitation using a T-type microchannel reactor. • Naked LDH nanosheets were dispersed in aqueous media. • LDH nanosheets can be used as building blocks for functional materials.

  13. Co-precipitation of phosphate and carbonate minerals: geological and ecological implications

    Science.gov (United States)

    Sanchez-Román, Monica; McKenzie, Judith; Vasconcelos, Crisogono

    2015-04-01

    Microorganisms play an important role in natural environments by controlling the metal cations (e.g., Ca2+, Mg2+, Fe2+) and the anions (CO32-, NH4+, PO43-) that precipitate as biominerals (e.g., carbonates, phosphates). In contrast to phosphate minerals, precipitation of carbonate minerals by bacteria has been widely studied in culture experiments and in natural environments. Moreover, studies of sedimentary phosphate minerals and their geological and ecological implications are rare. Nevertheless, phosphate minerals frequently co-precipitate with carbonates in culture experiments and in natural systems. In the present work, we investigate how microorganisms control the mineralogy and geochemistry of phosphate and carbonate minerals. For this, culture experiments were performed to study the co-precipitation of phosphate and carbonate minerals using aerobic heterotrophic bacteria at sedimentary Earth's surface conditions. Ca-Mg carbonate (dolomite, Mg-calcite) and/or Mg-carbonate (hydromagnesite) precipitated with Mg-phosphate (struvite). In most of the cultures, phosphate was the dominant mineral phase found in the bacterial precipitates and carbonates precipitated after phosphate phases. Notably, in all the cultures, we found a mixture of phosphate and carbonate minerals. This study shines new light into the microbial diagenetic processes involved in the co-precipitation of phosphate and carbonate minerals and links the P and C cycles.

  14. The Glomerular Filtration Barrier: Components and Crosstalk

    Directory of Open Access Journals (Sweden)

    Madhav C. Menon

    2012-01-01

    Full Text Available The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents—the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte. Understanding the pathomechanisms of inherited and acquired human diseases as well as experimental injury models of this barrier have helped to unravel this interdependence. Key among the consequences of interference with the integrity of the glomerular filtration barrier is the appearance of significant amounts of proteins in the urine. Proteinuria correlates with kidney disease progression and cardiovascular mortality. With specific reference to proteinuria in human and animal disease phenotypes, the following review explores the roles of the endothelial cell, glomerular basement membrane, and the podocyte and attempts to highlight examples of essential crosstalk within this barrier.

  15. Maize genome sequencing by methylation filtration.

    Science.gov (United States)

    Palmer, Lance E; Rabinowicz, Pablo D; O'Shaughnessy, Andrew L; Balija, Vivekanand S; Nascimento, Lidia U; Dike, Sujit; de la Bastide, Melissa; Martienssen, Robert A; McCombie, W Richard

    2003-12-19

    Gene enrichment strategies offer an alternative to sequencing large and repetitive genomes such as that of maize. We report the generation and analysis of nearly 100,000 undermethylated (or methylation filtration) maize sequences. Comparison with the rice genome reveals that methylation filtration results in a more comprehensive representation of maize genes than those that result from expressed sequence tags or transposon insertion sites sequences. About 7% of the repetitive DNA is unmethylated and thus selected in our libraries, but potentially active transposons and unmethylated organelle genomes can be identified. Reverse transcription polymerase chain reaction can be used to finish the maize transcriptome.

  16. The Perspective of Riverbank Filtration in China

    Science.gov (United States)

    Li, J.; Teng, Y.; Zhai, Y.; Zuo, R.

    2014-12-01

    Sustainable drinking water supply can affect the health of people, and the surrounding ecosystems. According to statistics of the monitoring program of drinking water sources in 309 at or above prefecture level of China in 2013, the major pollutants index were total phosphorus, ammonia and manganese in surface drinking water sources, respectively, iron, ammonia and manganese in groundwater drinking water sources, respectively. More than 150 drinking water emergency environmental accidents happened since 2006, 52 of these accidents led to the disruption of water supply in waterworks, and a population of over ten million were affected. It indicated that there is a potential risk for people's health by the use of river water directly and it is necessary to require alternative techniques such as riverbank filtration for improving the drinking water quality. Riverbank filtration is an inexpensive natural process, not only smoothing out normal pollutant concentration found in surface water but also significantly reducing the risk from such emergency events as chemical spill into the river. Riverbank filtration technique has been used in many countries more than 100 years, including China. In China, in 1950s, the bank infiltration technique was first applied in northeast of China. Extensive bank infiltration application was conducted in 1980s, and more than 300 drinking water sources utilities bank infiltration established mainly near the Songhua River Basin, the Yellow River Basin, Haihe River Basin. However, the comparative lack of application and researches on riverbank filtration have formed critical scientific data gap in China. As the performance of riverbank filtration technique depend on not only the design and setting such as well type, pumping rate, but also the local hydrogeology and environmental properties. We recommend more riverbank filtration project and studies to be conducted to collect related significant environmental geology data in China

  17. Salt disposition alternatives filtration at SRTC

    Energy Technology Data Exchange (ETDEWEB)

    Walker, B. W.; Hobbs, D.

    2000-01-27

    Several of the prospective salt disposition alternative technologies require a monosodium titanate (MST) contact to remove strontium and actinides from inorganic salt solution feedstock. This feedstock also contains sludge solids from waste removal operations and may contain defoamers added in the evaporator systems. Filtration is required to remove the sludge and MST solids before sending the salt solution for further processing. This report describes testing performed using the Parallel Theological Experimental Filter (PREF). The PREF contains two single tube Mott sintered metal crossflow filters. For this test one filter was isolated so that the maximum velocities could be achieved. Previous studies showed slurries of MST and sludge in the presence of sodium tetraphenylborate (NaTPB) were filterable since the NaTPB slurry formed a filter cake which aided in removing the smaller MST and sludge particles. Some of the salt disposition alternative technologies do not use NaTPB raising the question of how effective crossflow filtration is with a feed stream containing only sludge and MST. Variables investigated included axial velocity, transmembrane pressure, defoamer effects, and solids concentration (MST and sludge). Details of the tests are outlined in the technical report WSRC-RP-98-O0691. Key conclusions from this study are: (1) Severe fouling of the Mott sintered metal filter did not occur with any of the solutions filtered. (2) The highest fluxes, in the range of .46 to 1.02 gpm/f{sup 2}, were obtained when salt solution decanted from settled solids was fed to the filter. These fluxes would achieve 92 to 204 gpm filtrate production for the current ITP filters. The filtrate fluxes were close to the flux of 0.42 gpm/f{sup 2} reported for In Tank Precipitation Salt Solution by Morrisey. (3) For the range of solids loading studied, the filter flux ranged from .04 to .17 gpm/f{sup 2} which would result in a filtrate production rate of 9 to 31 gpm for the current HP

  18. Industrial investigations of the liquid steel filtration

    Directory of Open Access Journals (Sweden)

    K. Janiszewski

    2014-07-01

    Full Text Available Hitherto existing investigations concerning the ceramic filter use in the steel making processes have given good results. The obtained results of filtration have proved that this method may be used as an effective and cheap way of steel filtration from non-metallic inclusions. Placing filters in the tundish is the best location considering the limitation of the possibility of secondary pollution of steel. Yet, the results presented in this paper, of an experiment prepared and carried out in the industrial environment, are the only positive results obtained, which are connected with so much quantities of liquid steel processed with use of the multi-hole ceramic filters.

  19. Projective Dimension in Filtrated K-Theory

    DEFF Research Database (Denmark)

    Bentmann, Rasmus Moritz

    2013-01-01

    Under mild assumptions, we characterise modules with projective resolutions of length n∈N in the target category of filtrated K-theory over a finite topological space in terms of two conditions involving certain Tor -groups. We show that the filtrated K-theory of any separable C∗dash-algebra over...... any topological space with at most four points has projective dimension 2 or less. We observe that this implies a universal coefficient theorem for rational equivariant KK-theory over these spaces. As a contrasting example, we find a separable C∗dash-algebra in the bootstrap class over a certain five...

  20. Projective Dimension in Filtrated K-Theory

    DEFF Research Database (Denmark)

    Bentmann, Rasmus Moritz

    2013-01-01

    any topological space with at most four points has projective dimension 2 or less. We observe that this implies a universal coefficient theorem for rational equivariant KK-theory over these spaces. As a contrasting example, we find a separable C∗dash-algebra in the bootstrap class over a certain five......-point space, the filtrated K-theory of which has projective dimension 3. Finally, as an application of our investigations, we exhibit Cuntz-Krieger algebras which have projective dimension 2 in filtrated K-theory over their respective primitive spectrum....

  1. Mechanisms of pressure filtration of liquid aluminum alloys

    Science.gov (United States)

    Cao, X.

    2006-12-01

    The Prefil Footprinter, a portable pressure filtration instrument, is usually used to detect the quality of liquid aluminum alloys. However, no investigations have ever been done to calculate the cake resistance to date. Based on the identification and classification of flow behavior using the first derivative method for filtrate mass vs filtration time curves, conventional filtration equations are successfully employed to understand the filtration behaviors. From the analyses of the variations of cake resistance with filtration time, the filtration mechanisms are discussed in detail over the different filtration stages. During the steady stage, either incompressible or compressible cake mode is the main mechanism. At the initial and terminal transient stages, however, deep-bed filtration, complete straining, and solidification clogging may appear. Solid inclusions in liquid metal have significant influence on the cake structures and properties. Some important issues related to the heterogeneity of filter media and test methodology are highlighted in this work.

  2. Study on the adsorption of DNA on the layered double hydroxides (LDHs)

    Science.gov (United States)

    Li, Bin; Wu, Pingxiao; Ruan, Bo; Liu, Paiyu; Zhu, Nengwu

    2014-03-01

    Four kinds of layered double hydroxides (LDHs) were prepared by chemical coprecipitation method and used as DNA adsorbents. Multiple characterization tools such as power X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Standard electronic modules (SEM) were employed to characterize the LDHs. By examining the effect of initial concentration, solution pH, adsorption experiments were carried out to investigate the adsorption capacities of LDHs for DNA. The results revealed that the LDHs with Mg/Al = 3 had higher ability on adsorbing the DNA and were not affected by pH values. The LDHs exhibited excellent adsorption properties and completely adsorbed DNA within 2 h. The adsorption equilibrium data were fitted to the Langmuir and Freundlich models, showing that the Langmuir model which represented monolayer adsorption had better correlation with the adsorption linear equation. In addition, Circular dichroism (CD) spectrum, UV-vis spectorscopy and agarose gel electrophoresis revealed the integrity of DNA structure, suggesting that there had no damage on the DNA structure during the adsorption process.

  3. ADSORPTION OF PITCH AND STICKIES ON MAGNESIUM ALUMINUM HYDROXIDES TREATED AT DIFFERENT TEMPERAURES

    Directory of Open Access Journals (Sweden)

    Guodong Li

    2011-04-01

    Full Text Available Magnesium aluminum hydroxides (MAH of nitrate and carbonate forms were prepared by co-precipitation, dried at different temperatures, and employed as an adsorbent for pitch and stickies in papermaking. Results indicated that MAH that had been heat-treated had higher adsorption capacity to model pitch and stickies at neutral pH. Low-temperature-dried magnesium aluminum hydroxides of nitrate form (MAH-NO3 had higher adsorption capacity to model pitch and model stickies than those of the carbonate form (MAH-CO3. Increasing the drying temperature of MAH reduced the difference of adsorption capacity between MAH-NO3 and MAH-CO3. Higher-temperature-dried magnesium aluminum hydroxides also showed higher adsorption capacity to model pitch and stickies when the drying temperature was lower than 550 oC. MAH displayed higher adsorption capacity while a lower initial adsorption rate of model stickies than of model pitch. The model pitch and stickies were adsorbed on MAH significantly by charge neutralization and distributed mainly on the surface of the platelets of magnesium aluminum hydroxides. The experimental isothermal adsorption data of model pitch and stickies on MAH dried at 500 oC fit well to the Freundlich and Dubinin–Radushkevich isotherm equations.

  4. Aerosol filtration - performance of filter media; Filtration des aerosols - performances des medias filtrants

    Energy Technology Data Exchange (ETDEWEB)

    Bemer, D.; Regnier, R. [Institut National de Recherche et de Securite (INRS), Dept. Ingenierie des Procedes, 75 - Paris (France); Calle, S.; Thomas, D.; Simon, X.; Appert-Collin, J.Ch. [Centre National de la Recherche Scientifique (CNRS), Lab. des Sciences du Genie Chimique de Nancy, 54 - Vandoeuvre-les-Nancy (France)

    2006-03-15

    Set up in 2000, the Laboratoire de Filtration des Aerosols in Nancy (LFA), associating research teams from INRS (Institut National de Recherche et de Securite and LSGC (Laboratoire des Sciences du Genie Chimique - CNRS), has been commissioned to provide expertise in the aerosol filtration field to both CRAM (Caisse Regionale de l'Assurance Maladie) prevention specialists and industrialists. Following a theoretical review of fibre medium filtration, this paper summarises the different actions undertaken by the LFA: filter performance during clogging with liquid and solid aerosols, modelling, pneumatic unclogging of baghouse dust collectors, influence of micro-leaks, etc. (authors)

  5. Prevention of febrile nonhemolytic transfusion reaction with leucocyte filtrated concentrates

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu-ming; XIANG Guo-chun; ZHANG Jia-si; CHENG Xiao-ling; LI Ru-qing

    2002-01-01

    Objective: To assess the clinical efficiency of the transfusion of leucocyte filtrated RBC concentrates to prevent febrile nonhemolytic transfusion reactions (FNHTRs). Methods: One hundred patients with liver cirrhosis, gastric ulcer or cancer were subjected to receive RBC concentrates after leucocyte filtration.Another 50 patients with similar diseases were selected to receive non-filtrated RBC concentrates. The incidence of FNHTRs in all patients was investigated. Results: There was no FNHTR in 100 transfusions with leucocyte filtrated RBC concentrates, while FNHTRs occurred in 8 of 50 patients with non-filtrated RBC concentrates, with the incidence of 160%. Conclusion: FNHTRs to RBC transfusion can be prevented with leucocyte filtration.

  6. SEPARATION OF Ca AND Fe METAL ION IN SOURCE WATER BY ADSORPTION COLUMN TECHNIC WITH LOCAL ZEOLITE AND ACTIVE CARBON

    Directory of Open Access Journals (Sweden)

    Suyanta Suyanta

    2016-04-01

    Full Text Available This research aims are to separate of Ca and Fe metal ion in source water, with local zeolite and active carbon by adsorption column technic. Efficiency of separation are control by adsorption time and size of zeolite. Method that used was column adsorption with a flow system in which sample is applied to the filtration tube containing zeolite and active carbon. Initial and final concentrations of the samples were analyzed using Atomic Adsorption Spectrophotometer instrument. The results obtained shows that ability adsorption of zeolite to Ca and Fe metal ion are a good. Zeolite 1 (10 mesh can reduce iron concentration until 93.98 % and zeolite 2 (5mesh until 98.88% for 1 – 4 week range time. Whereas reducing of calcium concentration is not good, until 2 week period time adsorption of calcium ion is about 50%.   Keywords: adsorption, zeolite, source water

  7. Recyclable removal of bisphenol A from aqueous solution by reduced graphene oxide-magnetic nanoparticles: adsorption and desorption.

    Science.gov (United States)

    Zhang, Yixuan; Cheng, Yuxiao; Chen, Ningning; Zhou, Yuyan; Li, Bingyu; Gu, Wei; Shi, Xinhao; Xian, Yuezhong

    2014-05-01

    Reduced graphene oxide (rGO) nanosheets decorated with tunable magnetic nanoparticles (MNPs) were synthesized by a simple co-precipitation method and employed for recyclable removal of bisphenol A (BPA) from aqueous solution. The morphological characterization shows that Fe3O4 nanoparticles are uniformly deposited on rGO sheets. The magnetic characterization demonstrates that composites with various amounts of Fe3O4 nanoparticles are superparamagnetic. Due to the superparamagnetism, rGO-MNPs were used as recyclable adsorbents for BPA removal in aqueous solution. The kinetics of the adsorption process and the adsorption isotherm were investigated. The results indicate that the adsorption process is fitted to Langmuir model and the composites with lower density of MNPs represent better adsorption ability. In addition, its kinetics follows pseudo-second-order rate equation. Moreover, the adsorbents could be recovered conveniently by magnetic separation and recyclable used because of the easy desorption of BPA.

  8. Plasma discharge self-cleaning filtration system

    Science.gov (United States)

    Cho, Young I.; Fridman, Alexander; Gutsol, Alexander F.; Yang, Yong

    2014-07-22

    The present invention is directed to a novel method for cleaning a filter surface using a plasma discharge self-cleaning filtration system. The method involves utilizing plasma discharges to induce short electric pulses of nanoseconds duration at high voltages. These electrical pulses generate strong Shockwaves that disintegrate and dislodge particulate matter located on the surface of the filter.

  9. Filtration of engineered nanoparticles using porous membranes

    NARCIS (Netherlands)

    Trzaskus, Krzystof

    2016-01-01

    The research presented in this thesis aims at providing a better understanding of the fundamental aspects responsible for nanoparticle removal and fouling development during filtration of engineered nanoparticles. The emphasis is put on the role of interparticle interactions in the feed solution,

  10. [Clinical experience of automated double filtration plasmapheresis].

    Science.gov (United States)

    Lee, C T; Chuang, F R; Hsu, K T; Lam, K K; Liao, S C; Liu, C C; Chen, J B; Jang, S W; Chien, Y S; Pan, H H

    1996-12-01

    Double filtration plasmapheresis, one kind of fractionation plasmapheresis, was developed from membrane type plasmapheresis to remove only the pathogen and return the normal protein back to the patient. We started our automated double filtration plasmapheresis since December 1993. There were 13 patients who received one hundred treatments totally during one year period. And they are myasthenia gravis (8 patients); acute inflammatory demyelinating polyneuropathy (1 patient), multiple myeloma (1 patient); acquired factor VIII inhibitor (1 patient); autoimmune hemolytic anemia (1 patient); systemic lupus erythematous (1 patient). Technically double filtration plasmapheresis is easy to perform and time-saving. It also makes necessity of replacement fluid less frequent. Incidence of complication is rare, and this includes hypotension 2%, palpitation 1%, headache 1%, hemolysis 4%, air emboli 1%, high secondary pressure 2%, and no motality during our treatment. Clinical response is documented in cases of myasthenia gravis; acute inflammatory demyelinating polyneuropathy and acquired factor VIII inhibitor in our study. In conclusion, double filtration plasmapheresis is a time-saving, convenient, and safe therapeutic modality with rare complication. Because its effectiveness on limited kinds of diseases and costs relatively high price, thus plasmapheresis should be used in selected cases and treat aggressively if indicated.

  11. Advances in hot gas filtration technology

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.

    The past decade has seen the introduction of new filter media specifically designed for 'hot-gas' filtration. These media are available as woven or knitted fabrics and as non-wovens, i.e. needled felts. Needlefelted fabrics have proven so highly successful in the dedusting of hot gases that they are widely used nowadays in this new and necessary technology. Hot-gas filtration offers advantages in, for example, the saving or recycling of energy, the elimination of the cooling process, and the short-circuiting of process steps. This paper gives a survey of the types of textile fibres available for hot-gas filtration from the more recently developed organic fibres to refractory fibres. It describes, compares and contrasts their salient properties and lists the uses to which they may be put. It concentrates on such fibres which are generally referred to as 'high performance materials', since they are expected to provide satisfactory performance under extreme conditions of temperature, chemical environment and mechanical stress. It touches on filtration theory governing the collection mechanism. 9 refs., 7 figs., 3 tabs.

  12. Using Digital Filtration for Hurst Parameter Estimation

    Directory of Open Access Journals (Sweden)

    J. Prochaska

    2009-06-01

    Full Text Available We present a new method to estimate the Hurst parameter. The method exploits the form of the autocorrelation function for second-order self-similar processes and is based on one-pass digital filtration. We compare the performance and properties of the new method with that of the most common methods.

  13. Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

    2006-01-01

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  14. Interfacial adsorption of insulin. Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, S.H.; Bukrinsky, J.T.; Elofsson, U.; Norde, W.; Frokjaer, S.

    2006-01-01

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  15. ENVIRONMENTAL MANAGEMENT SCIENCE PROGRAM PROJECT NUMBER 87016 CO-PRECIPITATION OF TRACE METALS IN GROUNDWATER AND VADOSE ZONE CALCITE: IN SITU CONTAINMENT AND STABILIZATION OF STRONTIUM-90 AND OTHER DIVALENT METALS AND RADIONUCLIDES AT ARID WESTERN DOE SITES

    Energy Technology Data Exchange (ETDEWEB)

    Ferris, F. Grant; Fujita, Yoshiko; Smith, Robert W.

    2004-06-15

    Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. In situ containment and stabilization of these contaminants in vadose zones or groundwater is a cost-effective treatment strategy. Our facilitated approach relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal coprecipitation) by increasing groundwater pH and alkalinity (Fujita et al., 2000; Warren et al., 2001). Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation processes are irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from groundwater. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution (Zachara et al., 1991), solid solution properties of the trace metal in calcite (Tesoriero and Pankow, 1996), and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning, and how this occurs in aquifers and vadose environments is lacking. This report summarizes work undertaken during the second year of this project.

  16. ENVIRONMENTALMANAGEMENT SCIENCE PROGRAM PROJECT NUMBER 87016 CO-PRECIPITATION OF TRACEMETALS INGROUNDWATER AND VADOSE ZONE CALCITE: IN SITU CONTAINMENT AND STABILIZATION OF STRONTIUM-90 ANDOTHER DIVALENT METALS AND RADIONUCLIDES AT ARIDWESTERN DOE SITES

    Energy Technology Data Exchange (ETDEWEB)

    Ferris, F. Grant; Fujita, Yoshiko; Smith, Robert W.; Cosgrove, Donna M.; Colwell, F. S.

    2004-06-15

    Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. In situ containment and stabilization of these contaminants in vadose zones or groundwater is a cost-effective treatment strategy. Our facilitated approach relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal coprecipitation) by increasing groundwater pH and alkalinity (Fujita et al., 2000; Warren et al., 2001). Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation processes are irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from groundwater. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution (Zachara et al., 1991), solid solution properties of the trace metal in calcite (Tesoriero and Pankow, 1996), and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning, and how this occurs in aquifers and vadose environments is lacking. This report summarizes work undertaken during the second year of this project.

  17. OPTIMIZATION OF THE PROCESS OF DRYING THE FILTRATE DISTILLERY DREGS

    Directory of Open Access Journals (Sweden)

    A. A. Shevtsov

    2013-01-01

    Full Text Available The interactions of various factors affecting the process of drying the filtrate distillery dregs are investigated. Rational conditions for the process of drying the filtrate distillery dregs in a spray dryer are obtained.

  18. Internal filtration, filtration fraction, and blood flow resistance in high- and low-flux dialyzers.

    Science.gov (United States)

    Schneditz, Daniel; Zierler, Edda; Vanholder, Raymond; Eloot, Sunny

    2014-01-01

    It was the aim to examine the fluid flow in blood and dialysate compartments of highly permeable hollow fiber dialyzers where internal filtration contributes to solute removal but where excessive filtration bears a risk of cell activation and damage. Flow characteristics of high- (HF) and low-flux (LF) dialyzers were studied in lab-bench experiments using whole bovine blood. Measurements obtained under different operating conditions and under zero net ultrafiltration were compared to theoretical calculations obtained from a mathematical model. Experimental resistances in the blood compartment were within ±2% of those calculated from the model when dialysate was used as a test fluid. With whole blood, the experimental resistances in the blood compartment were only 81.8 ± 2.8% and 83.7 ± 4.3% of those calculated for the LF and HF dialyzer, respectively. Surprisingly, measured blood flow resistance slightly but significantly decreased with increasing flow rate (p filtration fraction, while overall internal filtration increased. The increase in internal filtration when increasing blood flow is associated with a beneficial reduction in internal filtration fraction. Concerns of increased hemoconcentration when increasing blood flow therefore appear to be unwarranted.

  19. Structural stability of coprecipitated natural organic matter and ferric iron under reducing conditions

    Science.gov (United States)

    Henneberry, Yumiko K.; Kraus, Tamara E.C.; Nico, Peter S.; Horwath, William R.

    2012-01-01

    The objective was to assess the interaction of Fe coprecipitated with dissolved organic matter (DOM) and its effect on Fe (hydr)oxide crystallinity and DOM retention under abiotic reducing conditions. A Fe-based coagulant was reacted with DOM from an agricultural drain and the resulting precipitate (floc) was exposed to S(-II) and Fe(II). Solution concentrations of Fe(II/III) and DOM were monitored, floc crystallinity was determined using X-ray diffraction, and the composition and distribution of functional groups were assessed using scanning transmission X-ray microscopy (STXM) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Results indicate coprecipitation of Fe(III) with DOM forms a non-crystalline floc that withstands crystallization regardless of change in pH, Fe:DOM ratio and type of reductant added. There was no evidence that exposure to reducing conditions led to release of DOM from the floc, indicating that coprecipitation with complex natural DOM in aquatic environments may stabilize Fe (hydr)oxides against crystallization upon reaction with reduced species and lead to long term sequestration of the DOM. STXM analysis identified spatially distinct regions with remarkable functional group purity, contrary to the model of DOM as a relatively uniform complex polymer lacking identifiable organic compounds. Polysaccharide-like OM was strongly and directly correlated with the presence of Fe but showed different Fe binding strength depending on the presence of carboxylic acid functional groups, whereas amide and aromatic functional groups were inversely correlated with Fe content.

  20. An innovative carbonate coprecipitation process for the removal of zinc and manganese from mining impacted waters

    Science.gov (United States)

    Sibrell, P.L.; Chambers, M.A.; Deaguero, A.L.; Wildeman, T.R.; Reisman, D.J.

    2007-01-01

    Although mine drainage is usually thought of as acidic, there are many cases where the water is of neutral pH, but still contains metal species that can be harmful to human or aquatic animal health, such as manganese (Mn) and zinc (Zn). Typical treatment of mine drainage waters involves pH adjustment, but this often results in excessive sludge formation and removal of nontoxic species such as magnesium and calcium. Theoretical consideration of the stability of metal carbonate species suggests that the target metals could be removed from solution by coprecipitation with calcium carbonate. The U.S. Geological Survey has developed a limestone-based process for remediation of acid mine drainage that increases calcium carbonate saturation. This treatment could then be coupled with carbonate coprecipitation as an innovative method for removal of toxic metals from circumneutral mine drainage waters. The new process was termed the carbonate coprecipitation (CCP) process. The CCP process was tested at the laboratory scale using a synthetic mine water containing 50 mg/L each of Mn and Zn. Best results showed over 95% removal of both Mn and Zn in less than 2 h of contact in a limestone channel. The process was then tested on a sample of water from the Palmerton zinc superfund site, near Palmerton, Pennsylvania, containing over 300 mg/L Zn and 60 mg/L Mn. Treatment of this water resulted in removal of over 95% of the Zn and 40% of the Mn in the limestone channel configuration. Because of the potential economic advantages of the CCP process, further research is recommended for refinement of the process for the Palmerton water and for application to other mining impacted waters as well. ?? Mary Ann Liebert, Inc.

  1. Thermodynamic Analysis on the Coprecipitation of Ni-Co-Mn Hydroxide

    Science.gov (United States)

    Li, Ling; Li, Yunjiao; Li, Lin; Chen, Nanxiong; Han, Qiang; Zhang, Xianzhen; Xu, Hu

    2017-10-01

    The thermodynamic data of various species in Ni-H2O, Co-H2O, Mn-H2O, and Ni-Co-Mn-H2O systems were obtained by thermodynamic calculation. The potential-pH diagrams for Ni-H2O, Co-H2O, and Mn-H2O systems at different ion activities at 323 K (50 °C), as well as Ni-Co-Mn-H2O complex systems at activity 1.00 at 298 K, 323 K, and 373 K (25 °C, 50 °C, and 100 °C) were constructed, respectively. The costable regions of Ni(OH)2, Co(OH)2, and Mn(OH)2 are verified to be thermodynamically stable in aqueous solution, which indicates the thermodynamic possibility of Ni-Co-Mn hydroxide coprecipitation. The potential-pH diagrams show that the temperature and ion activity have significant effects on the coprecipitation process. As the temperature increases or the ion activity decreases, the coprecipitation region of the Ni-Co-Mn hydroxide narrows. Moreover, the metal oxides, rather than the metal hydroxide, are more easily formed when the temperature increases. Experimental confirmation was performed to further verify the constructed potential-pH diagrams. The Ni-Co-Mn hydroxide with typical hexagonal CdI2 structure and quasi-spherical morphology was successfully obtained, and the SEM results show the uniform distribution of the elements Ni, Co, and Mn. The experimental results confirm the reliability of the prediction of thermodynamics analysis.

  2. Nanostructured yttrium aluminum garnet powders synthesized by co-precipitation method using tetraethylenepentamine

    Institute of Scientific and Technical Information of China (English)

    李先学; 王文菊

    2009-01-01

    Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-precipitation method without controlling the pH value during precipitation process.The original precursor was analyzed by thermogravimetry/differential scanning calorimetry(TG/DSC).The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by X-ray ...

  3. A coprecipitation technique to prepare ZnNb2O6 powders

    Indian Academy of Sciences (India)

    V V Deshpande; M M Patil; S C Navale; V Ravi

    2005-06-01

    A simple coprecipitation technique was successfully applied for the preparation of pure ultrafine single phase, ZnNb2O6 (ZN). Ammonium hydroxide was used to precipitate Zn2+ and Nb5+ cations as hydroxides simultaneously. This precursor on heating at 750°, produced ZN powders. For comparison, ZN powders were also prepared by the traditional solid state method. The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD). Particle size and morphology were studied by transmission electron spectroscopy (TEM).

  4. Effect of sintering on structural and electrical properties of co-precipitated Mn-Zn ferrites

    Science.gov (United States)

    Mehmood, S.; Zahra, F.; Rehman, M. A.

    2016-08-01

    Mn-Zn ferrite is one of the important class of soft ferrites. These are famous for possessing high initial permeability. In the present work, we have studied the effect of sintering on Mn-Zn nano particles. The particles were synthesized using co-precipitation method. The structural characterization of the prepared sample after each sintering step were done by using XRD. The XRD analysis showed the spinel structure. The electrical properties were studied as a function of temperature. It was observed that dielectric constant, loss tangent and AC conductivity varies with respect to temperature. The prepared composition is useful in microwave devices.

  5. Synthesis and characterization of laurate-intercalated Mg–Al layered double hydroxide prepared by coprecipitation

    DEFF Research Database (Denmark)

    Gerds, Nathalie Christiane; Katiyar, Vimal; Koch, Christian Bender

    2012-01-01

    Effective utilization of layered double hydroxides (LDH) for industrial applications requires the synthesis of pure and well-defined LDH phases. In the present study, dodecanoate (laurate) anions were intercalated into Mg–Al-layered double hydroxide (LDH-C12) by coprecipitation in the presence...... intercalated structure, but we here demonstrate it to be magnesium laurate (Mg-C12). The LDH-C12 compound showed high structural order with a basal spacing of 2.41nm. Fourier-transform IR-spectra confirmed the intercalation of the laurate anions in the interlayer. Transmission electron microscopy showed plate...

  6. Spectroscopic properties of Eu3+ doped YBO3 nanophosphors synthesized by modified co-precipitation method

    Institute of Scientific and Technical Information of China (English)

    A. Szczeszak; S. Lis; V. Nagirnyi

    2011-01-01

    Y1-xEuxBO3 nanophosphors were synthesized by a modified co-precipitation method.The structure of the obtained nanocrystals was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM).The average crystallite size was calculated from the full-width at half-maximum (FWHM) of the diffraction peaks by the Scherrer equation.The average particles size was 25±10 nm.The spectroscopic properties of the Y1-xEuxBO3 nanoborates were characterized by excitation and emission spectra under UV and VUV excitation.In order to improve colour purity,the chromaticity coordinates were also calculated.

  7. Synthesis, Characterization of Nano Tin Oxide via Co-precipitation Method

    Directory of Open Access Journals (Sweden)

    K. Sujatha

    2016-09-01

    Full Text Available Pure SnO2 nano powders were synthesized by co-precipitation method. The structure, surface, optical, and functional groups were analyzed by X-ray diffraction, FESEM, UV-Vis spectroscopy, FTIR and fluorescence spectra, respectively. The results were compared with pure tin oxide nanoparticle. X-ray analysis shows that the obtained power has tetragonal rutile structure with average crystallite size of 34 nm. Band gap is observed from UV-Vis spectroscopy. Fluorescence spectrum of pure sample detected a strong emission peaks at 634nm due to surface defect and oxygen vacancies in SnO2 nanoparticles.

  8. Pore Structure Evolution of Lanthana–Alumina Systems Prepared through Coprecipitation

    NARCIS (Netherlands)

    Nair, Jalajakumari; Nair, Padmakumar; Mizukami, Fujio; Ommen, van Jan G.; Doesburg, Giel B.M.; Ross, Julian R.H.; Burggraaf, Anthonie J.

    2000-01-01

    Pure Al2O3 and different compositions of La2O3–Al2O3 samples have been prepared through coprecipitation. Even after heating at 1300°C, the compositions La2O3·11Al2O3 and La2O3·13Al2O3 had higher surface area compared to the pure Al2O3 and the La2O3·Al2O3 composition. Ethanol washing is an effective

  9. Avrami behavior of magnetite nanoparticles formation in co-precipitation process

    Directory of Open Access Journals (Sweden)

    Ahmadi R.

    2011-01-01

    Full Text Available In this work, magnetite nanoparticles (mean particle size about 20 nm were synthesized via coprecipitation method. In order to investigate the kinetics of nanoparticle formation, variation in the amount of reactants within the process was measured using pH-meter and atomic absorption spectroscopy (AAS instruments. Results show that nanoparticle formation behavior can be described by Avrami equations. Transmission electron microscopy (TEM and X-ray diffraction (XRD were performed to study the chemical and morphological characterization of nanoparticles. Some simplifying assumptions were employed for estimating the nucleation and growth rate of magnetite nanoparticles.

  10. Technology Review of Modern Gas Turbine Inlet Filtration Systems

    OpenAIRE

    2012-01-01

    An inlet air filtration system is essential for the successful operation of a gas turbine. The filtration system protects the gas turbine from harmful debris in the ambient air, which can lead to issues such as FOD, erosion, fouling, and corrosion. These issues if not addressed will result in a shorter operational life and reduced performance of the gas turbine. Modern day filtration systems are comprised of multiple filtration stages. Each stage is selected based on the local operating envir...

  11. Nanostructured BiVO4 photocatalysts synthesized via a polymer-assisted coprecipitation method and their photocatalytic properties under visible-light irradiation

    Science.gov (United States)

    García-Pérez, U. M.; Sepúlveda-Guzmán, S.; Martínez-de la Cruz, A.

    2012-03-01

    Nanostructured BiVO4 photocatalysts were synthesized by a coprecipitation process in the presence of sodium carboxymethylcellulose (CMC), which acts as a steric stabilizer during the formation and growth of the BiVO4 nanoparticles. Samples with different contents of CMC were prepared in order to study the effect of the polymer on the final morphology of the oxide. The synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and adsorption-desorption isotherms (BET). The presence of CMC during the first stage of BiVO4 synthesis, promoted the formation of granular particles controlling its morphology and favoring its dispersion. The BiVO4 monoclinic polymorph (m-BiVO4) was obtained free of the tetragonal crystalline form (t-BiVO4) by annealing at different temperatures, which were influenced by CMC content: 400 °C (0.5 wt %), 450 °C (3.0 wt %), and 350 °C (6.0 and 9.0 wt %). BiVO4 nanoparticles showed photocatalytic activity, as they bleached an aqueous solution of rhodamine B (rhB) under visible-light irradiation. The photocatalytic activity of the BiVO4 samples was directly correlated with the amount of CMC added during the synthesis process.

  12. Structural and magnetic properties of Co{sub 1-} {sub x} Zn {sub x} Fe{sub 2}O{sub 4} nanoparticles by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Vaidyanathan, G. [Department of Physics, Pondicherry Engineering College, Pondicherry 605014 (India)]. E-mail: gvn_pec@yahoo.com; Sendhilnathan, S. [Department of Physics, Sri Manakula Vinayagar Engineering College, Pondicherry 605 107 (India)]. E-mail: sendhil29@yahoo.co.in; Arulmurugan, R. [Department of Physics, Pondicherry Engineering College, Pondicherry 605014 (India)]. E-mail: arulphysics@rediffmail.com

    2007-06-15

    Co{sub 1-} {sub x} Zn {sub x} Fe{sub 2}O{sub 4} nanoparticles were prepared by co-precipitation method with x varying from 0 to 1.0. The powder samples were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Fourier transform infrared spectroscopy (FTIR). The average crystallite sizes of the particles were determined from XRD. X-ray analysis showed that the samples were cubic spinel. The average crystallite size (D {sub aveXR}) of the particles precipitated was found to vary from 6.92 to 12.02 nm decreasing with the increase in zinc substitution. The lattice constant (a {sub o}) increased with the increase in zinc substitution. The specific saturation magnetization (M {sub S}) of the particles was measured at room temperature. The magnetic parameters such as M {sub S}, H {sub c}, and M {sub r} were found to decrease with the increase in zinc substitution. FTIR spectra of the Co{sub 1-} {sub x} Zn {sub x} Fe{sub 2}O{sub 4} with x varying from 0 to 1.0 in the range 400-4000 cm{sup -1} were reported. The spinel structure and the crystalline water adsorption of Co{sub 1-} {sub x} Zn {sub x} Fe{sub 2}O{sub 4} nanoparticles were studied by using FTIR.

  13. Effect of calcination temperature on the photocatalytic activity of TiO2 powders prepared by co-precipitation of TiCl3

    Science.gov (United States)

    Yudoyono, Gatut; Ichzan, Nur; Zharvan, Vicran; Daniyati, Rizqa; Santoso, Hadi; Indarto, Bachtera; Pramono, Yono Hadi; Zainuri, Mochamad; Darminto

    2016-04-01

    The adsorption of basic dye methylene blue (MB) onto titanium dioxide (titania) powder that were prepared by coprecipitation method of TiCl3 and NH4OH as iniatial material with different calcination temperature was studied to examine the photocatalytic activity. Synthesis process carried out by the solution pH was adjusted to be 8. Effect of calcination temperature on the titania powder were characterized with Differential Scanning Calorimetry/Thermogravimetry (DSC/TG), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The result of TG and XRD showed that the NH4Cl decomposed between 235-372°C. The XRD result showed that the anatase TiO2 only contained a single phase when the calcination temperature of the precursor at 800°C, and over which it began to grow rutile phase. The influence of synthesis condition on the photocatalytic activity of TiO2 powder was determined by the photodegradation of MB dye under UV light.

  14. Sintering study of NiO-YSZ composite obtained by coprecipitation route; Estudo de sinterabilidade do composito de NiO-YSZ obtido pela rota de coprecipitacao

    Energy Technology Data Exchange (ETDEWEB)

    Yoshito, W.K.; Resitivo, T.A.G.; Ussui, V.; Lazar, D.R.R.; Paschoal, J.O.A., E-mail: wyoshito@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2009-07-01

    NiO-YSZ composite is a widely used anode material for solid oxide fuel cell. The main purpose of the present work was the evaluation of the appropriate conditions of ceramic processing, by sintering behavior study of NiO-YSZ pressed powders, synthesized by hydroxide coprecipitation route. Using the empirical rate equation developed by Makipirtti-Meng, it was analyzed shrinkage rate in the temperature ranges of 900-1400 deg C as function of time. The powders were characterized by X-ray diffraction, scanning electron microscopy, gas adsorption, laser diffraction and helium picnometry. The microstructural characterization of the samples was evaluated by X-ray diffraction, scanning electron microscopy and relative density by the Archimedes method. It was found that activation energy value is 48,3 kJ.mol{sup -1} in the temperature range of 900-950 deg C and 604,83 kJ.mol{sup -1} for 1000-1200 deg C. These values correspond to the change that occurs in the microstructure during the heat treatment process. The sintering process was evaluated by the dilatometry date treatment. (author)

  15. Effect of calcination temperature on the photocatalytic activity of TiO{sub 2} powders prepared by co-precipitation of TiCl{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yudoyono, Gatut, E-mail: gyudoyono@physics.its.ac.id; Ichzan, Nur; Zharvan, Vicran; Daniyati, Rizqa; Santoso, Hadi; Indarto, Bachtera; Pramono, Yono Hadi; Zainuri, Mochamad; Darminto, E-mail: darminto@physics.its.ac.id [Department of Physics, Institut Teknologi Sepuluh Nopember (ITS), Kampus ITS Sukolilo, Surabaya 60111 (Indonesia)

    2016-04-19

    The adsorption of basic dye methylene blue (MB) onto titanium dioxide (titania) powder that were prepared by coprecipitation method of TiCl{sub 3} and NH{sub 4}OH as iniatial material with different calcination temperature was studied to examine the photocatalytic activity. Synthesis process carried out by the solution pH was adjusted to be 8. Effect of calcination temperature on the titania powder were characterized with Differential Scanning Calorimetry/Thermogravimetry (DSC/TG), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The result of TG and XRD showed that the NH{sub 4}Cl decomposed between 235-372°C. The XRD result showed that the anatase TiO{sub 2} only contained a single phase when the calcination temperature of the precursor at 800°C, and over which it began to grow rutile phase. The influence of synthesis condition on the photocatalytic activity of TiO{sub 2} powder was determined by the photodegradation of MB dye under UV light.

  16. Application of dissolvable layered double hydroxides as sorbent in dispersive solid-phase extraction and extraction by co-precipitation for the determination of aromatic acid anions.

    Science.gov (United States)

    Tang, Sheng; Lee, Hian Kee

    2013-08-06

    Three types of magnesium-aluminum layered double hydroxides were synthesized and employed as solid-phase extraction (SPE) sorbents to extract several aromatic acids (protocatechuic acid, mandelic acid, phthalic acid, benzoic acid, and salicylic acid) from aqueous samples. An interesting feature of these sorbents is that they dissolve when the pH of the solution is lower than 4. Thus, the analyte elution step, as needed in conventional sorbent-based extraction, was obviated by dissolving the sorbent in acid after extraction and separation from the sample solution. The extract was then directly injected into a high-performance liquid chromatography-ultraviolet detection system for analysis. In the key adsorption process, both dispersive SPE and co-precipitation extraction with the sorbents were conducted and experimental parameters such as pH, temperature, and extraction time were optimized. The results showed that both extraction methods provided low limits of detection (0.03-1.47 μg/L) and good linearity (r(2) > 0.9903). The optimized extraction conditions were applied to human urine and sports drink samples. This new and interesting extraction approach was demonstrated to be a fast and efficient procedure for the extraction of organic anions from aqueous samples.

  17. Determination of {sup 234}U and {sup 238}U in seawater samples by alpha spectrometry after concentration of U(VI) onto hydrotalcite and co-precipitation with LaF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Suc, N.V. [University of Technical Education Ho Chi Minh City (Viet Nam); Bich, T.T. [Center for Nuclear Techniques, Ho Chi Minh City (Viet Nam)

    2013-07-01

    This paper presents a simple and accurate method for determination of uranium isotopes ({sup 234}U and {sup 238}U) in seawater samples using alpha spectrometry. Uranium is pre-concentrated from seawater samples via adsorption on hydrotalcite at pH 6.5. The absorbent is dissolved into 50 ml of 8M HNO{sub 3}; then filtered through a Dowex-1 column. U(VI) in the elution solution is reduced to U(IV) using zinc metal in 4M solution of HCl and then co-precipitated with LaF{sub 3}. The chemical separation efficiency is found to be 97.12 {+-} 2.68%, eliminating the need of using {sup 232}U tracer in other published methods. This method is validated via comparison with results obtained using inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA) for three seawater samples. (orig.)

  18. 40 CFR 141.171 - Criteria for avoiding filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.171 Criteria for avoiding filtration. In addition to...

  19. 40 CFR 141.174 - Filtration sampling requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration sampling requirements. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.174 Filtration sampling requirements. (a)...

  20. 40 CFR 141.71 - Criteria for avoiding filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.71 Criteria for avoiding filtration. A public water system that uses a surface water source must meet all...

  1. Origins of the poor filtration characteristics of wheat starch hydrolysates

    NARCIS (Netherlands)

    Matser, A.M.; Steeneken, P.A.M.

    1998-01-01

    The effects of wheat starch components on the filtration characteristics of wheat starch hydrolysates were investigated with a model-based approach. The filtration rate was not affected by the removal of the pentosans or by altering the conformation of the protein. On the other hand, the filtration

  2. Factors of Impacting the Coprecipitation Process for Synthesizing CoTi-substitued Barium M-type Ferrite Ultrafine Powder

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wen-yu; ZHANG Qing-jie ZHANG Qing-jie; GUAN Jian-guo

    2004-01-01

    The effect of pH values on synthesizing single-phase CoTi-substituted barium M-type ferrite ultrafine powders,and BaCoTiFe10O19, was investigated employing corrosion versus pH plot (E-pH plot) for metal element, thermodynamic calculation, and co-dump coprecipitation. The pH values of complete coprecipitation of all Fe3+, Ti4+, Co2+ and Ba2+ cations are 9-12 and higher than 7.9 on the basis of E-pH plot analysis and thermodynamic calculation, respectively. The minimum pH value necessary to the formation of single-phase BaCoTiFe10O19 is 8.5 in the light of the co-dump coprecipitation.These results indicate that the coprecipitation process for synthesizing CoTi-substituted barium M-type ferrite ultrafine powders is simultaneously influenced by synergetic coprecipation effect of cations and coordination effect of Cl anions. The test time of the minimum pH value corresponding to forming a series of single-phase CoTi-substituted barium M-type ferrite ultrafine powders,and BaCoxTixFe12-2xO19, may be significantly reduced by using the effects of two new factors on the coprecipitation process.

  3. Sorption and coprecipitation of copper to ferrihydrite and humic acid organomineral complexes and controls on copper availability.

    Science.gov (United States)

    Seda, Neila N; Koenigsmark, Faye; Vadas, Timothy M

    2016-03-01

    Coprecipitation of Fe oxide and organic matter in redox dynamic sediments controls the net retention and form of Cu in the solid precipitates. In this study, coprecipitation and sorption of Cu with organomineral precipitation solids formed at different Fe:organic carbon (OC) ratios were compared for net Cu removal and extractability. As more humic acid was present during precipitation of Fe, TEM images indicated smaller Fe oxide particles formed within an organic matrix as expected. In coprecipitation reactions, as the ratio of Fe:OC decreased, more Cu was removed from solution at pH 5.5 and below. However, in sorption reactions, there was an inhibition of Cu removal at low OC concentrations. As the pH increased from 5.5 to 7 and as solution phase OC concentration increased, more Cu remained dissolved in both coprecipitation and sorption reactions. The addition of Ca(2+), glycine, histidine and citric acid or lowering the pH resulted in more extractable Cu from the coprecipitation compared with the sorption reactions. The variations in Cu extraction were likely due to a combination of a more amorphous structure in CPT products, and the relative abundance of available Fe oxide or OC binding sites. This has implications for the assumption of additivity in binding phases and for researchers conducting binding or exposure experiments.

  4. Nanoparticles filtration by leaked fibrous filters

    Energy Technology Data Exchange (ETDEWEB)

    Mouret, Guillaume; Calle-Chazelet, Sandrine; Thomas, Dominique; Appert-Collin, Jean-Christophe [Nancy-Universite/LSGC/CNRS - 1 rue Grandville - BP 20451 - F-54001 Nancy Cedex (France)], E-mail: sandrine.calle@ensic.inpl-nancy.fr; Bemer, Denis [INRS - Avenue de Bourgogne - F-54501 Vandoeuvre les Nancy Cedex (France)

    2009-05-01

    The aim of this work is first to measured nanoparticles penetration through three different fiberglass filters intentionally-pierced with calibrated needles at different filtration velocity. Then a semi-empirical model based on the air flow resistances of the new and perforated filter media and on the mechanism of Brownian diffusion for the collection of ultrafine particles by the media enables to well predict the efficiency observed for all tested operating conditions. Results show that the increase of particles penetration is all the more important that the pinhole is large and that the particle diameter is low. Another result is that the filtration efficiency of the new filter media controlled the penetration. A high efficiency filter with a high resistance to air flow will be more damaged than a low efficiency filter when being perforated.

  5. Integrative filtration research and sustainable nanotechnology

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Drew Thompson; David Y.H.Pui

    2013-01-01

    With the wide applications of nanomaterials in an array of industries,more concerns are being raised about the occupational health and safety of nanoparticles in the workplace,and implications of nanotechnology on the environment and living systems.Studies on environmental,health and safety (EHS) issues of nanomaterials play a significant role in public acceptance,and eventual sustainability,of nanotechnology.We present research results on three aspects of the EHS studies:characterization and measurement of nanoparticles,nanoparticle emission and exposure at workplaces,and control and abatement of nanoparticle release using filtration technology.Measurement of nanoparticle agglomerates using a newly developed instrument,the Universal Nanoparticle Analyzer,is discussed.Nanoparticle emission and exposure measurement results for carbon nanotubes in the manufacture of nanocomposites and for silicon nanoparticles in their production at a pilot scale facility are presented.Filtration of nanoparticles and nanoparticle agglomerates are also studied.

  6. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    Demands for better indoor air quality are increasing, since we spend most of our time indoors and we are more and more aware of indoor air pollution. Field studies in different parts of the world have documented that high percentage of occupants in many offices and buildings find the indoor air...... decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air...... cleaning techniques. Supply air filter is one of the key components in the ventilation system. Studies have shown that used ventilation filters themselves can be a significant source of indoor air pollution with consequent impact on perceived air quality, sick building syndrome symptoms and performance...

  7. Ultrasonic filtration of industrial chemical solutions

    Science.gov (United States)

    Cosma, T.

    1974-01-01

    The practical results obtained as a result of filtering industrial chemical solutions under continuous flow conditions with the aid of an ultrasonic filter are presented. The main part of the assembly consists of an ultrasonic generator with an output power of about 400 W and the filtration assembly, in which there is a magnetostrictive amplifier constructed for 20.5 kHz. In addition to ensuring a continuous flow of filtered solution, ultrasonic filters can be replaced or cleaned at intervals of time that are 8-10 times greater than in the case of mechanical filters. They yield considerably better results as far as the size of the filtered particles is concerned. The parameters on which filtration quality depends are also presented.

  8. Breakthrough of cyanobacteria in bank filtration.

    Science.gov (United States)

    Pazouki, Pirooz; Prévost, Michèle; McQuaid, Natasha; Barbeau, Benoit; de Boutray, Marie-Laure; Zamyadi, Arash; Dorner, Sarah

    2016-10-01

    The removal of cyanobacteria cells in well water following bank filtration was investigated from a source water consisting of two artificial lakes (A and B). Phycocyanin probes used to monitor cyanobacteria in the source and in filtered well water showed an increase of fluorescence values demonstrating a progressive seasonal growth of cyanobacteria in the source water that were correlated with cyanobacterial biovolumes from taxonomic counts (r = 0.59, p cyanobacteria. Of cyanobacteria that passed through bank filtration, smaller cells were significantly more frequent in well water samples (p cyanobacteria to wells. Winter samples demonstrated that cyanobacteria accumulate within bank filters, leading to continued passage of cells beyond the bloom season. Although no concentrations of total microcystin-LR were above detection limits in filtered well water, there is concern that cyanobacterial cells that reach the wells have the potential to contain intracellular toxins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. [Adsorption of methylene blue from aqueous solution onto magnetic Fe3O4/ graphene oxide nanoparticles].

    Science.gov (United States)

    Chang, Qing; Jiang, Guo-Dong; Hu, Meng-Xuan; Huang, Jia; Tang, He-Qing

    2014-05-01

    A simple ultrasound-assisted co-precipitation method was developed to prepare magnetic Fe3O4/graphene oxide (Fe3O4/ GO) nanoparticles. The characterization with transmission electron microscope (TEM) indicated that the products possessed small particle size. The hysteresis loop of the dried Fe3O4/GO nanoparticles demonstrated that the sample had typical features of superparamagnetic material. Batch adsorption studies were carried out to investigate the effects of the initial pH of the solution, the dosage of adsorbent, the contact time and temperature on the adsorption of methylene blue. The results indicated that the composites prepared could be used over a broad pH range (pH 6-9). The adsorption process was very fast within the first 25 min and the equilibrium was reached at 180 min. The adsorption equilibrium and kinetics data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption process was a spontaneous and endothermic process in nature. The composite exhibited fairly high adsorption capacity (196.5 mg.g-1) of methylene blue at 313 K. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field, and then regenerated by hydrogen peroxide and recycled for further use. The results indicated that the adsorbent had a potential in the application of the dye wastewater treatment.

  10. Better adsorption capacity of SnO2 nanoparticles with different graphene addition

    Science.gov (United States)

    Paramarta, V.; Taufik, A.; Saleh, R.

    2016-11-01

    The adsorption capacity of SnO2 nanoparticle has been studied by graphene and nanographene platelets (NGP) additions using co-precipitation method. The crystalline phase, composition, and morphology of the samples are analyzed using X-Ray Diffraction (XRD), Energy Dispersive X-Ray (EDX), Fourier Transform Infrared Spectroscopy (FT-IR), and Transmission Electron Microscope (TEM). Tetragonal structure of SnO2 is shown for the nanoparticle and its composites. The presence of graphene and NGP is also confirmed. The adsorption capacity of the nanoparticle and its composites are analyzed by observing the degradation of methylene blue (MB) as the organic dye model using UV-Vis Spectroscopy. The result shows that SnO2 composite with graphene achieves higher adsorption capacity of about 20% than the composite with NGP. The fitting of equilibrium adsorption capacity result indicates that the adsorption mechanism of SnO2 composite with graphene tends to follow the Langmuir adsorption-isotherm model.

  11. The filtration properties of a dimorphic yeast

    OpenAIRE

    McCarthy, Anthony A

    2001-01-01

    A dimorphic yeast Kluyveromyces marxianu var. marxianus NRRLy2415 which exhibits a wide range of mean morphological forms was used as a model organism to investigate the role of cell morphology on the dead-end and crossflow filtration behaviour. Varying the culturing conditions produced cell suspensions of different mean morphology. Batch fermentations were used to produce yeast-like morphologies and continuous cultures produced cells more mycelial in nature. Semi-automated image analysis was...

  12. Symptomatic hyponatremia during glomerular filtration rate testing

    OpenAIRE

    2010-01-01

    Hyponatremia affects nearly one in five of all hospitalized patients. Severe hyponatremia is associated with significant morbidity and mortality, and is therefore important to recognize. Prior reports have linked duloxetine with hyponatremia, but it is uncommon. In this case report, we describe a research subject taking duloxetine who developed severe symptomatic hyponatremia during glomerular filtration rate testing despite having undergone such testing uneventfully in the past.

  13. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    1997-01-01

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...

  14. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  15. Portable Hybrid Powered Water Filtration Device

    Directory of Open Access Journals (Sweden)

    Maria Lourdes V. Balansay

    2015-08-01

    Full Text Available The existing water filtration device has features that can be developed to be more useful and functional during emergency situations. The project’s development has been aided by following provisions in PEC, NEC, NEMA and Philippine National Standard for Safe Drinking Water provide standards for the construction of the project. These standards protect both the prototype and the user. These also served as guide for the maintenance of every component. The design of the portable hybrid powered water filtration device shows that the project has more advanced features such as portability and the power supply used such as photovoltaic module solar cells and manually operated generator. This also shows its effectiveness and reliability based on the results of discharging test, water quality test and water production test. Based on analysis of the overall financial aspects, the machine can be profitable and the amount of revenue and operating cost will increase as years pass. Using the proper machine/ tools and methods of fabrication helps in easy assembly of the project. The materials and components used are cost effective and efficient. The best time for charging the battery using solar panel is 9:00 am onwards while the hand crank generator is too slow because the generated current is little. The water filtration device is very efficient regarding the operating hours and water production. The machine may have a great effect to society and economy in generation of clean available water at less cost.

  16. Oxalate co-precipitation synthesis of calcium zirconate and calcium titanate powders.

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Sanchez, Bernadette A.; Tuttle, Bruce Andrew

    2009-06-01

    Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.

  17. Enhancement of MgAl2O4 spinel formation from coprecipitated precursor by powder processing

    Indian Academy of Sciences (India)

    Soumen Pal; A K Bandyopadhyay; S Mukherjee; B N Samaddar; P G Pal

    2011-07-01

    Although low temperature fast coprecipitation technique has been used to synthesize stoichiometric (MgO–nAl2O3, = 1) MgAl2O4 spinel forming precursor, delayed spinellization has always been the concern in this process. In this article, the precursor of this ‘fast technique’ has been used for bulk production by further processing by high speed mixing with solvents and mechanical activation by attrition milling in terms of superior spinellization. At 1000°C, MgAl2O4 – -Al2O3 solid solution and MgO phases are formed (spinel formed by 1000°C is regarded as primary spinel). At higher temperatures, due to large agglomerate size, MgO can not properly interact with the exsolved -Al2O3 from spinel solid solution to form secondary spinel; and consequently spinellization gets affected. Solvent treatment and attrition milling of the coprecipitated precursor disintegrate the larger agglomerates into smaller size (effect is more in attrition). Then MgO comes in proper contact with exsolved alumina, and therefore total spinel formation (primary + secondary) is enhanced. Extent of spinellization, for processed calcined samples where some alumina exists as solid solution with spinel, can be determined from the percentage conversion of MgO. Analysis of the processed powders suggests that the 4 h attrited precursor is most effective in terms of nano size (< 25 nm) stoichiometric spinel crystallite formation at ≤ 1100°C.

  18. Microstructure and hysteresis curves of samarium-holmium-iron garnet synthesized by coprecipitation

    Directory of Open Access Journals (Sweden)

    Caffarena Valeska da Rocha

    2003-01-01

    Full Text Available An investigation was made into the synthesis and magnetic properties of Sm(3-xHo xFe5O12 (samarium-holmium-iron garnet ferrite, as yet absent from the literature. The material in question was synthesized by co-precipitation, starting from hydrated chlorides of rare-earth elements and ferrous sulfate, and the mixed hydroxide co-precipitate was calcined at 1000 °C. Using PVA as a binder, rectangular cross section-shaped compacts were produced by means of steel-die pressing, drying and sintering from 1200 to 1450 °C. The main conclusions of this study were that the coercive force decreases as the sintering temperature increases, and that the effect of substituting holmium for samarium in SmIG is entirely different from that provided by replacing yttrium by gadolinium in YIG, which is the most important result of this work. An in-depth investigation will be necessary to determine the correlation between microstructure/magnetic properties and ceramic processing variables.

  19. Co-precipitation of oppositely charged nanoparticles: the case of mixed ligand nanoparticles

    Science.gov (United States)

    Moglianetti, Mauro; Ponomarev, Evgeniy; Szybowski, Maxime; Stellacci, Francesco; Reguera, Javier

    2015-11-01

    Colloid stability is of high importance in a multitude of fields ranging from food science to biotechnology. There is strong interest in studying the stability of small particles (of a size of a few nanometres) with complex surface structures, that make them resemble the complexity of proteins and other natural biomolecules, in the presence of oppositely charged nanoparticles. While for nanoparticles with homogeneously charged surfaces an abrupt precipitation has been observed at the neutrality of charges, data are missing about the stability of nanoparticles when they have more complex surface structures, like the presence of hydrophobic patches. To study the role of these hydrophobic patches in the stability of nanoparticles a series of negatively charged nanoparticles has been synthesized with different ratios of hydrophobic content and with control on the structural distribution of the hydrophobic moiety, and then titrated with positively charged nanoparticles. For nanoparticles with patchy nanodomains, the influence of hydrophobic content was observed together with the influence of the size of the nanoparticles. By contrast, for nanoparticles with a uniform distribution of hydrophobic ligands, size changes and hydrophobic content did not play any role in co-precipitation behaviour. A comparison of these two sets of nanoparticles suggests that nanodomains present at the surfaces of nanoparticles are playing an important role in stability against co-precipitation.

  20. Aerosol Filtration Application Using Fibrous Media An Industrial Perspective

    Institute of Scientific and Technical Information of China (English)

    杨传芳

    2012-01-01

    Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory, followed by a brief review on the advancement of filtration media. After that, filtration applications in respiratory protection, dust collection, and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China's fast pace economical development endeavor, where air filtration enables the protection of human health, environment and equipment for sustainability.

  1. Filtration Combustion in Smoldering and SHS

    Science.gov (United States)

    Matkowsky, Bernard J.

    2001-01-01

    Smolder waves and SHS (self-propagating high-temperature synthesis) waves are both examples of filtration combustion waves propagating in porous media. Smoldering combustion is important for the study of fire safety. Smoldering itself can cause damage, its products are toxic and it can also lead to the more dangerous gas phase combustion which corresponds to faster propagation at higher temperatures. In SHS , a porous solid sample, consisting of a finely ground powder mixture of reactants, is ignited at one end. A high temperature thermal wave, having a frontal structure, then propagates through the sample converting reactants to products. The SHS technology appears to enjoy a number of advantages over the conventional technology, in which the sample is placed in a furnace and "baked" until it is "well done". The advantages include shorter synthesis times, greater economy, in that the internal energy of the reactions is employed rather than the costly external energy of the furnace, purer products, simpler equipment and no intrinsic limitation on the size of the sample to be synthesized as exists in the conventional technology. When delivery of reactants through the pores to the reaction site is an important aspect of the combustion process, it is referred to as filtration combustion. The two types of filtration combustion have a similar mathematical formulation, describing the ignition, propagation and extinction of combustion waves in porous media. The goal in each case, however, is different. In smoldering the desired goal is to prevent propagation, whereas in SHS the goal is to ensure propagation of the combustion wave, leading to the synthesis of desired products. In addition, the scales in the two areas of application differ. Smoldering generally occurs at lower temperatures and propagation velocities than in SHS nevertheless, the two applications have much in common so that what is learned fit make application can be used to advantage in the other. In porous

  2. Nanofiber filter media for air filtration

    Science.gov (United States)

    Raghavan, Bharath Kumar

    Nanofibers have higher capture efficiencies in comparison to microfibers in the submicron particle size range of 100-500 nm because of small fiber diameter and increased surface area of the fibers. Pressure drop across the filter increases tremendously with decrease in fiber diameter in the continuum flow regime. Nanofibers with fiber diameter less than 300 nm are in the slip flow regime as a consequence of which steep increase in pressure drop is considerably reduced due to slip effect. The outlet or inlet gases have broad range of particle size distribution varying from few micrometers to nanometers. The economic benefits include capture of a wide range of particle sizes in the gas streams using compact filters composed of nanofibers and microfibers. Electrospinning technique was used to successfully fabricate polymeric and ceramic nanofibers. The nanofibers were long, continuous, and flexible with diameters in the range of 200--300 nm. Nanofibers were added to the filter medium either by mixing microfibers and nanofibers or by directly electrospinning nanofibers as thin layer on the surface of the microfiber filter medium. Experimental results showed that either by mixing Nylon 6 nanofibers with B glass fibers or by electrospinning Nylon 6 nanofibers as a thin layer on the surface of the microfiber medium in the surface area ratio of 1 which is 0.06 g of nanofibers for 2 g of microfibers performed better than microfiber filter media in air filtration tests. This improved performance is consistent with numerical modeling. The particle loading on a microfibrous filter were studied for air filtration tests. The experimental and modeling results showed that both pressure drop and capture efficiency increased with loading time. Nanofiber filter media has potential applications in many filtration applications and one of them being hot gas filtration. Ceramic nanofibers made of alumina and titania nanofibers can withstand in the range of 1000°C. Ceramic nanofibers

  3. Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration

    Science.gov (United States)

    Voigt, Claudia; Jäckel, Eva; Taina, Fabio; Zienert, Tilo; Salomon, Anton; Wolf, Gotthard; Aneziris, Christos G.; Le Brun, Pierre

    2017-02-01

    The influence of filter surface chemistry on the filtration efficiency of cast aluminum alloys was evaluated for four different filter coating compositions (Al2O3—alumina, MgAl2O4—spinel, 3Al2O3·2SiO2—mullite, and TiO2—rutile). The tests were conducted on a laboratory scale with a filtration pilot plant, which facilitates long-term filtration tests (40 to 76 minutes). This test set-up allows the simultaneous use of two LiMCAs (before and after the filter) for the determination of the efficiency of inclusion removal. The four tested filter surface chemistries exhibited good thermal stability and mechanical robustness after 750 kg of molten aluminum had been cast. All four filter types exhibited a mean filtration efficiency of at least 80 pct. However, differences were also observed. The highest filtration efficiencies were obtained with alumina- and spinel-coated filter surfaces (>90 pct), and the complete removal of the largest inclusions (>90 µm) was observed. The efficiency was slightly lower with mullite- and rutile-coated filter surfaces, in particular for large inclusions. These observations are discussed in relation to the properties of the filters, in particular in terms of, for example, the surface roughness.

  4. Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration

    Science.gov (United States)

    Voigt, Claudia; Jäckel, Eva; Taina, Fabio; Zienert, Tilo; Salomon, Anton; Wolf, Gotthard; Aneziris, Christos G.; Le Brun, Pierre

    2016-12-01

    The influence of filter surface chemistry on the filtration efficiency of cast aluminum alloys was evaluated for four different filter coating compositions (Al2O3—alumina, MgAl2O4—spinel, 3Al2O3·2SiO2—mullite, and TiO2—rutile). The tests were conducted on a laboratory scale with a filtration pilot plant, which facilitates long-term filtration tests (40 to 76 minutes). This test set-up allows the simultaneous use of two LiMCAs (before and after the filter) for the determination of the efficiency of inclusion removal. The four tested filter surface chemistries exhibited good thermal stability and mechanical robustness after 750 kg of molten aluminum had been cast. All four filter types exhibited a mean filtration efficiency of at least 80 pct. However, differences were also observed. The highest filtration efficiencies were obtained with alumina- and spinel-coated filter surfaces (>90 pct), and the complete removal of the largest inclusions (>90 µm) was observed. The efficiency was slightly lower with mullite- and rutile-coated filter surfaces, in particular for large inclusions. These observations are discussed in relation to the properties of the filters, in particular in terms of, for example, the surface roughness.

  5. Structural characterization of mixed uranium-plutonium co-precipitates and oxides synthesized by oxalic co-conversion route

    Energy Technology Data Exchange (ETDEWEB)

    Arab-Chapelet, B.; De Bruycker, F.; Picart, S.; Leturcq, G.; Grandjean, S. [Laboratoire de Chimie des Actinides, CEA Valrho, bat 399, BP17171, 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    In this study, mixed uranium(IV)-plutonium(III) oxalate co-precipitates with Pu/(U+Pu) molar ratio equal to 29 and 45% were synthesized and characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). The thermal conversion step of these co-precipitates into oxide was carried out under argon flow up to 700 deg. C leading to mixed oxides. The structural investigation on these oxides indicates the formation of (U,Pu)O{sub 2} fluorite-type solid solution characterized by a very homogeneous distribution of plutonium and uranium, a controlled oxygen stoichiometry and well-defined morphology of particles. (authors)

  6. Comparative study on the preparation of Uranium source using a Cerium fluoride Co-precipitation method and an Electrodeposition method

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Han-Byeol; Park, Seunghoon; Shin, Jung-Ki; Ahn, Gil Hoon; Chung, Heejun; Kwak, Sung-Woo [Korea Institute of Nonproliferation and control, Daejeon (Korea, Republic of)

    2015-05-15

    This analysis can be used to identify the undeclared nuclear activities of North Korea. The international community has developed a method of collecting and analyzing uranium particles within a limited time in the field to determine whether or not undeclared nuclear activities have taken place. This study shows the U source using CeF{sub 3} coprecipitation has no significant difference. In addition, this CeF{sub 3} coprecipitation method is simple and time saving. It is expected to be useful for rapid on-site detection of undeclared uranium enrichment activities.

  7. Biorepellent Organic Coatings for Improved Microsieve Filtration

    NARCIS (Netherlands)

    Rosso, M.; Schroën, C.G.P.H.; Zuilhof, H.

    2009-01-01

    Microsieves are a new type of Si-based membranes, which are coated with a SixN4 top layer. Although SixN4 is known to be relatively inert, surface contamination (fouling through e.g. protein adsorption) is critical for application in microfiltration. As a result, surface modification is needed to pr

  8. Removal of aqueous nC60 fullerene from water by low pressure membrane filtration.

    Science.gov (United States)

    Floris, R; Nijmeijer, K; Cornelissen, E R

    2016-03-15

    The potential environmental and health risks of engineered nanoparticles such as buckminsterfullerene C60 in water require their removal during the production of drinking water. We present a study focusing on (i) the removal mechanism and (ii) the elucidation of the role of the membrane pore size during removal of nC60 fullerene nanoparticle suspensions in dead-end microfiltration and ultrafiltration mimicking separation in real industrial water treatment plants. Membranes were selected with pore sizes ranging from 18 nm to 500 nm to determine the significance of the nC60 to membrane pore size ratio and the adsorption affinity between nC60 and membrane material during filtration. Experiments were carried out with a dead-end bench-scale system operated at constant flux conditions including a hydraulic backwash cleaning procedure. nC60 nanoparticles can be efficiently removed by low pressure membrane technology with smaller and, unexpectedly, also by mostly similar or larger pores than the particle size, although the nC60 filtration behaviour appeared to be different. The nC60 size to membrane pore size ratio and the ratio of the cake-layer deposition resistance to the clean membrane resistance, both play an important role on the nC60 filtration behaviour and on the efficiency of the backwash procedure recovering the initial membrane filtration conditions. These results become specifically significant in the context of drinking water production, for which they provide relevant information for an accurate selection between membrane processes and operational parameters for the removal of nC60 in the drinking water treatment.

  9. Reverse osmosis concentrate treatment via a PAC-MF accumulative countercurrent adsorption process.

    Science.gov (United States)

    Zhao, Chunxia; Gu, Ping; Cui, Hangyu; Zhang, Guanghui

    2012-01-01

    Organic pollutants in reverse osmosis (RO) concentrates from wastewater reclamation are mainly comprised of low molecular weight biorefractory compounds. Generally, advanced oxidation methods for oxidizing these organics require a relatively high level of energy consumption. In addition, conventional adsorption removal methods require a large dose of activated carbon. However, the dose can be reduced if its full adsorption capacity can be used. Therefore, the combined technology of powdered activated carbon (PAC) adsorption and microfiltration (MF) membrane filtration was studied to develop a countercurrent two-stage adsorption process. A PAC accumulative adsorption prediction method was proposed based on the verification of a PAC multi-stage adsorption capacity equation. Moreover, the prediction method was amended for a more accurate prediction of the effluent quality because adsorption isotherm constants were affected by the initial adsorbate concentration. The required PAC dose for the accumulative countercurrent two-stage adsorption system was 0.6 g/L, whereas that of the conventional adsorption process was 1.05 g/L when the dilution factor(F) was 0.1 and the COD and DOC removal rates were set to 70% and 68.1%, respectively. Organic pollutants were satisfactorily removed with less consumption of PAC. Effluent from this combined technology can be further reclaimed by an RO process to improve the overall recovery rate to between 91.0% and 93.8% with both economic and environmental benefits.

  10. Adsorption combined with ultrafiltration to remove organic matter from seawater.

    Science.gov (United States)

    Tansakul, Chatkaew; Laborie, Stéphanie; Cabassud, Corinne

    2011-12-01

    Organic fouling and biofouling are the major severe types of fouling of reverse osmosis (RO) membranes in seawater (SW) desalination. Low pressure membrane filtration such as ultrafiltration (UF) has been developed as a pre-treatment before reverse osmosis. However, UF alone may not be an effective enough pre-treatment because of the existence of low-molecular weight dissolved organic matter in seawater. Therefore, the objective of the present work is to study a hybrid process, powdered activated carbon (PAC) adsorption/UF, with real seawater and to evaluate its performance in terms of organic matter removal and membrane fouling. The effect of different PAC types and concentrations is evaluated. Stream-activated wood-based PAC addition increased marine organic matter removal by up to 70% in some conditions. Moreover, coupling PAC adsorption with UF decreased UF membrane fouling and the fouling occurring during short-term UF was totally reversible. It can be concluded that the hybrid PAC adsorption/UF process performed in crossflow filtration mode is a relevant pre-treatment process before RO desalination, allowing organic matter removal of 75% and showing no flux decline for short-term experiments.

  11. ANNUAL REPORT FOR ENVIRONMENTAL MANAGEMENT SCIENCE PROGRAM PROJECT NUMBER 87016 CO-PRECIPITATION OF TRACE METALS IN GROUNDWATER AND VADOSE ZONE CALCITE: IN SITU CONTAINMENT AND STABILIZATION OF STRONTIUM-90 AND OTHER DIVALENT METALS AND RADIONUCLIDES AT ARID WESTERN DOE SITES

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Robert W.; Fujita, Yoshiko; Ferris, F. Grant; Cosgrove, Donna M.; Colwell, F. S.

    2003-06-15

    Radionuclide and metal contaminants such as 90Sr are present beneath U.S. Department of Energy (DOE) lands in both the groundwater (e.g., 100-N area at Hanford, WA) and vadose zone (e.g., Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory). In situ containment and stabilization of these contaminants is a cost-effective treatment strategy. However, implementing in situ containment and stabilization approaches requires definition of the mechanisms that control contaminant sequestration. We are investigating the in situ immobilization of radionuclides or contaminant metals (e.g., 90Sr) by their facilitated co-precipitation with calcium carbonate in groundwater and vadose zone systems. Our facilitated approach, shown schematically in Figure 1, relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity. Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation process tends to be irreversible and many western aquifers are saturated with respect to calcite, the coprecipitated metals and radionuclides will be effectively removed from the aqueous phase over the long-term. Another advantage of the ureolysis approach is that the ammonium ions produced by the reaction can exchange with radionuclides sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture in a more stable solid phase (co-precipitation rather than adsorption).

  12. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces...... is monitored simultaneously and the influence from the presence of other human serum proteins on albumin and IgG adsorption, as well as their mutual influence during adsorption processes, is investigated. Exploring protein adsorption by combining analysis of competitive adsorption from complex solutions...... of high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces...

  13. Low temperature synthesis of nanocrystalline lanthanum monoaluminate powders by chemical coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C.-L. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Wang, C.-L. [Department of Materials Science and Engineering, I-Shou University, 1 Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung 840, Taiwan (China); Chen, T.-Y. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Chen, G.-J. [Department of Materials Science and Engineering, I-Shou University, 1 Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung 840, Taiwan (China); Hung, I-M. [Department of Chemical Engineering and Materials Science, Yuan Ze University, 135 Yuan-Tung Road, Chungli, Taoyuan 320, Taiwan (China); Shih, C.-J. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 807, Taiwan (China)]. E-mail: CJShih@kmu.edu.tw; Fung, K.-Z. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China)

    2007-08-16

    Nanocrystalline lanthanum monoaluminate (LaAlO{sub 3}) powders were prepared by chemical coprecipitation using 25 vol.% of NH{sub 4}OH, 0.05 M La(NO{sub 3}){sub 3}.6H{sub 2}O and 0.05 M Al(NO{sub 3}){sub 3}.9H{sub 2}O aqueous solutions as the starting materials. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analyses (TGA/DTA), X-ray diffraction (XRD), Raman spectrometry, specific surface area (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) were utilized to characterize the LaAlO{sub 3} powders prepared by chemical coprecipitation. The crystallization temperature of the LaAlO{sub 3} precursor gels precipitated at pH 9 is estimated as 810 deg. C by TG/DTA. The XRD pattern of the LaAlO{sub 3} precursor gels precipitated at pH 8-12 and calcined at 700 deg. C for 6 h shows a broad arciform continuum exist between 24{sup o} and 32{sup o} and sharp peaks of LaAlO{sub 3} except the precursor gels precipitated at pH 9. For the LaAlO{sub 3} precursor gels precipitated at pH 9 and calcined at 700 deg. C for 6 h, the formation of the perovskite LaAlO{sub 3} phase occurs and the presence of crystalline impurities is not found. The crystallite size of LaAlO{sub 3} slightly increases from 37.8 to 41.5 nm with calcination temperature increasing from 700 to 900 deg. C for 6 h. The LaAlO{sub 3} powders prepared by chemical coprecipitation have a considerably large specific surface of 30 m{sup 2}/g. The relative density greater than 97% is obtained when these nanocrystalline LaAlO{sub 3} powders are sintered at 1550 deg. C for 2 h.

  14. Transfer and transport of aluminum in filtration unit

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Aluminum salt coagulants were used prevalently in various water works. In this article, the effects of filtration on residual aluminum concentration and species distribution were researched by determining the concentration of different Aluminum species before and after single layer filter, double layer filter, and membrane filtration units. In the research, size exclusion chromatography (SEC) was used to separate colloidal and soluble aluminum, ion exchange chromatography (IEC) was used to separate organic and inorganic aluminum, and inductivity coupled plasma-atomic emission spectrometry (ICP-AES) was used to determine the aluminum concentration. The results showed that the rapid filtration process had the ability of removing residual aluminum from coagulant effluent water, and that double layer filtration was more effective in residual aluminum removal than single layer filtration, while Nano filtration was more effective than micro filtration. It was found that when the residual aluminum concentration was below 1mg/L in sediment effluent, the residual aluminum concentration in treated water was above 0.2 mg/L. The direct rapid filtration process mainly removed the suspended aluminum. The removal of soluble and colloidal aluminum was always less than 10% and the natural small particles that adsorbed the amount of soluble or small particles aluminum on their surface were difficult to be removed in this process. Micro filtration and nano filtration were good technologies for removing aluminum; the residual aluminum concentration in the effluent was less than 0.05 mg/L.

  15. Martingale representation property in progressively enlarged filtrations

    CERN Document Server

    Jeanblanc, M

    2012-01-01

    Consider $\\mathbb{G}$ the progressive enlargement of a filtration $\\mathbb{F}$ with a random time $\\tau$. Assuming that, in $\\mathbb{F}$, the martingale representation property holds, we examine conditions under which the martingale representation property holds also in $\\mathbb{G}$. It is noted that the classical results on this subject are no more sufficient to deal with all examples coming from credit risk modeling. In this paper, we introduce a new methodology which extends the various classical results and applies on recent examples.

  16. New magnetic-enhanced adsorption process for wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cotten, G.B.; Navratil, J.D. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States); Sebesta, F. [Czech Tech Univ. (Czech Republic)

    1999-09-01

    Radioactive and nonradioactive metal ion and particulate species in aqueous solutions present a formidable treatment problem for the nuclear and commercial industries. An economical and highly effective system for the treatment of wastewater containing these metal species is presented that uses a new magnetic enhanced adsorption technique. The process employs low-cost magnetite (FeO{center_dot}Fe{sub 2}O{sub 3}) supported on various organic and inorganic support media, and an external magnetic field to couple the inherent sorption properties of the magnetite with a high gradient magnetic separation technique. This combination of sorption techniques offers several advantages over current filtration and ion exchange systems and removes a variety of heavy metals and radioactive species. Filtration systems do not remove ionic species, and ion exchange systems can be plugged by particulate matter, which may limit the amount of exchange sites able to be accessed.

  17. The effect of cyanobacterial biomass enrichment by centrifugation and GF/C filtration on subsequent microcystin measurement.

    Science.gov (United States)

    Rogers, Shelley; Puddick, Jonathan; Wood, Susanna A; Dietrich, Daniel R; Hamilton, David P; Prinsep, Michele R

    2015-03-10

    Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures) and with biomass enrichment (by centrifugation or GF/C filtration). After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.

  18. The Effect of Cyanobacterial Biomass Enrichment by Centrifugation and GF/C Filtration on Subsequent Microcystin Measurement

    Directory of Open Access Journals (Sweden)

    Shelley Rogers

    2015-03-01

    Full Text Available Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures and with biomass enrichment (by centrifugation or GF/C filtration. After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.

  19. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  20. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  1. Green and red luminescence in co-precipitation synthesized Pr:LuAG nanophosphor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. Arun; Kumar, K. Ashok; Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai–600 025, Tamil Nadu (India); Asokan, K. [Materials Science Group, Inter University Accelerator Centre, New Delhi-110067 (India)

    2016-05-06

    Pr:LuAG nanophosphor is an effective candidate in magnetic resonance imaging coupled positron emission tomography (MRI-PET) for medical imaging and scintillator applications. LuAG:Pr (0.05, 0.15 mol%) nanoscale ceramic powders were synthesized by co-precipitation method using urea as precipitant. Effect of antisite defect on structure and luminescence behavior was investigated. Pr:LuAG nanoceramic powders are found crystallized in cubic structure by high temperature calcination at 1400 °C and it shows antisite defect. HR-SEM analysis revealed spherically shaped Pr:LuAG nanoceramic particulate powders with ∼100 nm size. By the excitation at 450 nm, Pr:LuAG nanophosphor exhibit green to red luminescence in the wavelength range of 520 to 680 nm, which is originated from multiplet transition of Pr{sup 3+} ions.

  2. Synthesis of cerium oxide (CeO{sub 2}) nanoparticles using simple CO-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Farahmandjou, M.; Zarinkamar, M.; Firoozabadi, T. P., E-mail: farahamndjou@iauvaramin.ac.ir [Islamis Azad University, Varamin-Phisva Branch, Department of Physics, Varamin (Iran, Islamic Republic of)

    2016-11-01

    Synthesis of cerium oxide (CeO{sub 2}) nanoparticles was studied by new and simple co-precipitation method. The cerium oxide nanoparticles were synthesized using cerium nitrate and potassium carbonate precursors. Their physicochemical properties were characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (Sem), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (Ftir) and UV-Vis spectrophotometer. XRD pattern showed the cubic structure of the cerium oxide nanoparticles. The average particle size of CeO{sub 2} was around 20 nm as estimated by XRD technique and direct HRTEM observations. The surface morphological studies from Sem and Tem depicted spherical particles with formation of clusters. The sharp peaks in Ftir spectrum determined the existence of CeO{sub 2} stretching mode and the absorbance peak of UV-Vis spectrum showed the bandgap energy of 3.26 eV. (Author)

  3. TRANSPARENT CONDUCTING OXIDE SYNTHESIS OF ALUMINIUM DOPED ZINC OXIDES BY CHEMICAL COPRECIPITATION

    Directory of Open Access Journals (Sweden)

    Silvia Maioco

    2013-03-01

    Full Text Available Aluminium doped zinc oxides (AZO are promising replacements for tin doped indium oxides (ITO but thin films show a wide range of physical properties strongly dependent on deposition process conditions. Submicrometric 1% aluminum doped zinc oxide ceramics (AZO are examined, prepared by coprecipitation, from Zn(NO32 and Al(NO33 aqueous solutions, sintered at 1200°C and subsequently annealed in 10-16 atm controlled oxygen fugacity atmospheres, at 1000°C. Electrical resistivity diminishes by two orders of magnitude after two hours of annealing and the Seebeck coefficient gradually changes from -140 to -50 µV/K within 8 h. It is concluded that increased mobility is dominant over the increased carrier density, induced by changes in metal-oxygen stoichiometry

  4. A coprecipitation technique to prepare NaNbO3 and NaTaO3

    Indian Academy of Sciences (India)

    V Samuel; A B Gaikwad; V Ravi

    2006-04-01

    A simple coprecipitation technique has been used successfully for the preparation of pure, ultrafine, single phases of NaNbO3 (NN) and NaTaO3 (NT). An alcoholic solution of ammonium carbonate and ammonium hydroxide was used to precipitate Na+ and Nb5+ (or Ta5+) cations under basic conditions as carbonate and hydroxide, respectively. On heating at 700°C, these precursors produce respective products. For comparison, both NN and NT powders were also prepared by the traditional solid state method. The phase purity and lattice parameters were studied by powder X-ray diffraction (XRD). The particle size and morphology were studied by scanning electron microscopy (SEM).

  5. Structural & Magnetic Characterizations of NiLiZn Nanoferrites Synthesized by Co-precipitation Method

    Institute of Scientific and Technical Information of China (English)

    D.N. Rohadian; Z.A.Z. Jamal; S.B. Jamaludin; M.F. Bari; J. Adnan

    2011-01-01

    Synthesis of Ni0.sLixZn(0.5-x)Fe204 nanoparticles with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5 were realized via coprecipitation method. X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) measurements were performed on the samples to determine the characteristics of the crystal structures and the magnetic properties of the samples, respectively. The spinel phase structures of the samples were confirmed by XRD analysis. Patterns of decreased lattice parameter and increased crystallite size values were observed by increasing the Li concentration at longer synthesis reaction periods. Similarly, for the magnetic properties, both the saturation magnetization (Ms) and coercivity (Hc) were found to vary with increasing patterns at higher Li doping levels and longer synthesis reaction periods. The results and mechanisms concerned were discussed.

  6. Water-dispersed bone morphogenetic protein nanospheres prepared by co-precipitation method

    Institute of Scientific and Technical Information of China (English)

    江兵兵; 高长有; 胡玲; 沈家骢

    2004-01-01

    A modified complex coacervation-co-precipitation method was used to prepare bone morphogenetic protein(BMP)-loaded nanospheres. Three natural polymers were used as packing materials to obtain nanoscale delivery device for BMP,in the presence of phosphatidylcholine functioning as stabilizer. Positively charged polysaccharide, N,N-diethylaminoethyl dex-tran (DEAE-dextran) tended to form stable, uniform and smaller size particles carrying BMP. Negatively charged bovine serumalbumin (BSA) induced precipitation of the produced BMP particles due to its weak interaction with BMP molecules, although itproduced nanosized BMP spheres. While collagen, a weakly positively charged protein shaped larger particles due to the stronginteraction among themselves. A mechanism of co-precipitation process was also deduced to depict the formation of stablenanospheres.

  7. Development of a coprecipitation system for the speciation/preconcentration of chromium in tap waters

    Energy Technology Data Exchange (ETDEWEB)

    Karatepe, Aslihan, E-mail: karatepea@gmail.com [Nevsehir University, Faculty of Science and Arts, Department of Chemistry, 50000 Nevsehir (Turkey); Korkmaz, Esra [Bozok University, Faculty of Science and Arts, Department of Chemistry, Yozgat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Science and Arts, Chemistry Department, 38039 Kayseri (Turkey); Elci, Latif [Pamukkale University, Faculty of Science and Arts, Department of Chemistry, 20020 Denizli (Turkey)

    2010-01-15

    A method for the speciation of chromium(III), chromium(VI) and determination of total chromium based on coprecipitation of chromium(III) with dysprosium hydroxide has been investigated and applied to tap water samples. Chromium(III) was quantitatively recovered by the presented method, while the recovery values for chromium(VI) was below 10%. The influences of analytical parameters including amount of dysprosium(III), pH, centrifugation speed and sample volume for the quantitative precipitation were examined. No interferic effects were observed from alkali, earth alkali and some transition metals for the analyte ions. The detection limits (k = 3, N = 15) were 0.65 {mu}g/L for chromium(III) and 0.78 {mu}g/L for chromium(VI). The validation of the presented method was checked by the analysis of certified reference materials.

  8. Reverse water gas shift reaction over Co-precipitated Ni-CeO2 catalysts

    Institute of Scientific and Technical Information of China (English)

    WANG Luhui; ZHANG Shaoxing; LIU Yuan

    2008-01-01

    The Ni-CeO2 catalysts with different Ni contents were prepared by a co-precipitation method and used for Reverse Water Gas Shift (RWGS) reaction. 2wt.%Ni-CeO2 showed excellent catalytic performance in terms of activity, selectivity, and stability for RWGS reaction. Characterizations of the catalyst samples were conducted by XRD and TPR. The results indicated that, in Ni-CeO2 catalysts, there were three kinds of nickel, nickel ions in ceria lattice, highly dispersed NiO and bulk NiO. Oxygen vacancies were formed in CeO2 lattice due to the incorporation of Ni2+ ions into ceria lattice. Oxygen vacancies formed in ceda lattice and highly dispersed Ni were key active components for RWGS, and bulk Ni was key active component for methanation of CO2.

  9. Co-Precipitation Preparation and Luminescent Behavior of (Y,Gd)BO3∶ Eu Phosphor

    Institute of Scientific and Technical Information of China (English)

    鱼志坚; 黄小卫; 庄卫东; 崔向中; 何华强; 李红卫

    2004-01-01

    (Y,Gd)BO3∶ Eu phosphors were prepared by co-precipitation precursors, and luminescent properties were investigated. The precursors were synthesized by introducing hydroxyl ion to mixed solution of rare earth nitrates and boric acid, either through adding ammonia(precursor 1)or through controlled release of hydroxyl ion of urea(precursor 2). The precursors were fired in air at 1000 ℃ for 2 h. Resulted phosphor synthesized with precursor 1 has non-uniformed particle with mean diameter of about 3 μm, while that with precursor 2 exhibits uniformed near spherical-like morphology with mean diameter of about 300 nm. Phosphors with the two methods exhibit same crystal structure as that of commercial one. Emission spectra of the samples indicate that the sample prepared with precursor 2 shows relative higher intensity(exited by 172 nm VUV)than that prepared with the other precursor.

  10. Luminescence modification of Eu~(3+)-activated molybdate phosphor prepared via co-precipitation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chunlei; HU Yunsheng; ZHUANG Weidong; HUANG Xiaowei; HE Tao

    2009-01-01

    Eu-activated CaMoO_4 phosphors were co-precipitated in an aqueous solution, and NH_3·H_2O, NH_4HCO_3 and (NH_2)_2CO as pre-cipitating aid agents were compared based on the morphology and particle size distribution of the phosphor samples. Sm~(3+) as sensitizer ion was investigated on the luminescence of CaMoO_4:Eu, and it could strengthen the 406 nm absorption of this phosphor. At last, the scheelite CaMoO_4:Eu and wolframite ZnMoO_4:Eu were selected to compare their host absorption. The result showed that the scheelite molybdate host exhibited stronger UV absorption than wolframite one.

  11. Luminescence modification of Eu3+-activated molybdate phosphor prepared via co-precipitation

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Chunlei

    2009-01-01

    Eu-activated CaMoO4 phosphors were co-precipitated in an aqueous solution, and NH3·H2O, NH4HCO3 and (NH2)2CO as pre-cipitating aid agents were compared based on the morphology and particle size distribution of the phosphor samples. Sm3+ as sensitizer ion was investigated on the luminescence of CaMoO4:Eu, and it could strengthen the 406 nm absorption of this phosphor. At last, the scheelite CaMoO4:Eu and wolframite ZnMoO4:Eu were selected to compare their host absorption. The result showed that the scheelite molybdate host exhibited stronger UV absorption than wolframite one.

  12. Effect of pressure on the size of magnetite nanoparticles in the coprecipitation synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, F., E-mail: fyazdani@ccerci.ac.ir [Chemical Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of); Edrissi, M., E-mail: edrisi@aut.ac.ir [Chemical Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2010-07-25

    The effect of pressure on the size of magnetite nanoparticles synthesized by the coprecipitation technique was studied. It is generally believed that pressure has negligible effects, if any, on liquid and solid reactions. However, in this work it was shown that pressure has a significant effect on the size of magnetite nanoparticles. This could be attributed to the very high surface-to-volume ratio of nanosized particles and to some other physical properties of magnetite, such as supersaturation and surface tension. The increase in the size of the nanoparticles is explained by the change in the Gibbs free energy value during crystallization from a homogeneous supersaturated solution at higher pressures. This phenomenon could find important applications especially in biomedicine where a limitation on the maximum size of the nanoparticles will be desired.

  13. Characterization of ZnS nanoparticles synthesized by co-precipitation method

    Institute of Scientific and Technical Information of China (English)

    Parvaneh Iranmanesh; Samira Saeedni; Mohsen Nourzpoor

    2015-01-01

    ZnS nanoparticles are prepared by homogeneous chemical co-precipitation method using EDTA as a stabilizer and capping agent. The structural, morphological, and optical properties of as-synthesized nanoparticles are investigated us-ing x-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible (UV-Vis) absorption, and photoluminescence spectroscopy. The x-ray diffraction pattern exhibits a zinc-blended crystal structure at room temperature. The average particle size of the nanoparticles from the scanning electron microscopy image is about 50 nm. The ultraviolet absorption spectrum shows the blue shift in the band gap due to the quantum confinement effect. The photoluminescence spectrum of ZnS nanoparticles shows a blue visible spectrum.

  14. Synthesis of layered double hydroxide nanosheets by coprecipitation using a T-type microchannel reactor

    Science.gov (United States)

    Pang, Xiujiang; Sun, Meiyu; Ma, Xiuming; Hou, Wanguo

    2014-02-01

    The synthesis of Mg2Al-NO3 layered double hydroxide (LDH) nanosheets by coprecipitation using a T-type microchannel reactor is reported. Aqueous LDH nanosheet dispersions were obtained. The LDH nanosheets were characterized by X-ray diffraction, transmission electron microscopy, atomic force microscopy and particle size analysis, and the transmittance and viscosity of LDH nanosheet dispersions were examined. The two-dimensional LDH nanosheets consisted of 1-2 brucite-like layers and were stable for ca. 16 h at room temperature. In addition, the co-assembly between LDH nanosheets and dodecyl sulfate (DS) anions was carried out, and a DS intercalated LDH nanohybrid was obtained. To the best of our knowledge, this is the first report of LDH nanosheets being directly prepared in bulk aqueous solution. This simple, cheap method can provide naked LDH nanosheets in high quantities, which can be used as building blocks for functional materials.

  15. Magnetic properties of Fe-Ni nanoparticles prepared by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Davarpanah, A M; Sargazi, M [Department of Physics, University of Sistan and Baluchestan, Zahedan (Iran, Islamic Republic of); Mirzae, A A; Feizi, M [Department of Chemistry, University of Sistan and Baluchestan, Zahedan (Iran, Islamic Republic of)], E-mail: A.M.DAVARPANAH@hamoon.usb.ac.ir

    2008-08-15

    Many methods have been extended for the preparation of nanoparticles. One of the most important methods is the chemical wet process, e.g. the co-precipitation method that has been used for the preparation of Fe-Ni nanoparticles by the authors. XRD patterns show that the nanoparticles are amorphous before calcination and crystallized after calcination. SEM images show that the grain size of the Fe-Ni particles is in 50-300 nanometre range and that the texture of the nanoparticles after calcination was smoother than before calcination. Hysteresis loops show that the Fe-Ni nanoparticles are superparamagnetic before calcination, because the carbonate phase still exists in the sample, and that they are ferromagnetic materials after calcination. For 40Fe-60Ni nanoparticles after calcination, H{sub c} = 0.12 and B{sub s} = 4800 Oe, being very different in respect to the bulk 40Fe-60Ni alloy.

  16. Magnetic properties of Fe-Ni nanoparticles prepared by co-precipitation method

    Science.gov (United States)

    Davarpanah, A. M.; Mirzae, A. A.; Sargazi, M.; Feizi, M.

    2008-08-01

    Many methods have been extended for the preparation of nanoparticles. One of the most important methods is the chemical wet process, e.g. the co-precipitation method that has been used for the preparation of Fe-Ni nanoparticles by the authors. XRD patterns show that the nanoparticles are amorphous before calcination and crystallized after calcination. SEM images show that the grain size of the Fe-Ni particles is in 50-300 nanometre range and that the texture of the nanoparticles after calcination was smoother than before calcination. Hysteresis loops show that the Fe-Ni nanoparticles are superparamagnetic before calcination, because the carbonate phase still exists in the sample, and that they are ferromagnetic materials after calcination. For 40Fe-60Ni nanoparticles after calcination, Hc = 0.12 and Bs = 4800 Oe, being very different in respect to the bulk 40Fe-60Ni alloy.

  17. Microstructure of Yttria-Doped Ceria as a Function of Oxalate Co-Precipitation Synthesis Conditions

    Science.gov (United States)

    Brissonneau, Laurent; Mathieu, Aurore; Tormos, Brigitte; Martin-Garin, Anna

    2016-12-01

    In sodium fast reactors (SFR), dissolved oxygen in sodium can be monitored via potentiometric sensors with an yttria-doped thoria electrolyte. Yttria-doped ceria (YDC) was chosen as a surrogate material to validate the process of such sensors. The material must exhibit high density and a fine grain microstructure to be resistant to the corrosion by liquid sodium and thermal shocks. Thus, the oxalic co-precipitation route was chosen to avoid milling steps that could bring impurity incorporation which is suspected to induce grain boundary corrosion in sodium. The powder and sintered pellets examination show that the synthesis conditions are of primary importance on the process yield, the oxalate powder microstructure and, eventually, on the ceramic density and microstructure. The impurity content was limited by controlling the synthesis, calcination, and sintering steps.

  18. Synthesis of LaPO4:Ce, Terbium by Co-Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The synthesis of precursor of green phosphors, LaPO4:Ce, Tb, by means of co-precipitation with cocurrent flow feed was studied. The effects of the reaction temperature, the kind and concentration of the acid in the bottom water, and the charging rate on the physical properties, such as particle size, were investigated. It is found that the particle size of the powder is controllable by adjusting acidity in bottom water and charging rate. The powder with diameter size of 3 to 5 μm was obtained. Its XRD and SEM were analyzed. XRD patterns of the as-prepared green phosphor powders display the typical peaks of CePO4. SEM shows that the morphology of powders is ball-shaped.

  19. Water-dispersed bone morphogenetic protein nanospheres prepared by co-precipitation method

    Institute of Scientific and Technical Information of China (English)

    江兵兵; 高长有; 胡玲; 沈家骢

    2004-01-01

    A modified complex coacervation-co-precipitation method was used to prepare bone morphogenetic protein (BMP)-loaded nanospheres. Three natural polymers were used as packing materials to obtain nanoscale delivery device for BMP,in the presence of phosphatidylcholine functioning as stabilizer. Positively charged polysaccharide, N,N-diethylaminoethyl dex-tran (DEAE-dextran) tended to form stable, uniform and smaller size particles carrying BMP. Negatively charged bovine serum albumin (BSA) induced precipitation of the produced BMP particles due to its weak interaction with BMP molecules, although it produced nanosized BMP spheres. While collagen, a weakly positively charged protein shaped larger particles due to the strong interaction among themselves. A mechanism of co-precipitation process was also deduced to depict the formation of stable nanospheres.

  20. Modified release and antioxidant stable Lagenaria siceraria extract microspheres using co-precipitated starch.

    Science.gov (United States)

    Kulkarni, Sameer D; Sinha, Barij N; Kumar, K Jayaram

    2014-05-01

    Ca-alginate hydrogel beads of Lagenaria siceraria (LS) fruit extract using co-precipitates of LS seed starch and colloidal silicon dioxide (SSD) as filler was studied. Effect of different concentrations of SSD on the encapsulation efficiency, size of microspheres, moisture content and antioxidant potential of the microspheres comprising extract was determined. The chemical composition of ethanolic extract was analysed by LC-MS. The prepared microspheres were characterized by SEM, FTIR and XRD. The incorporation of filler in hydrogel beads modified the micromeritic properties and release profile of LS fruit extract. It is observed that fillers have improved the stability of antioxidant potential of the extract. The application of this technology would improve the stability of LS fruit extract in pharmaceutical and food products.

  1. Y-TZP ceramic processing from coprecipitated powders: a comparative study with three commercial dental ceramics.

    Science.gov (United States)

    Lazar, Dolores R R; Bottino, Marco C; Ozcan, Mutlu; Valandro, Luiz Felipe; Amaral, Regina; Ussui, Valter; Bressiani, Ana H A

    2008-12-01

    (1) To synthesize 3mol% yttria-stabilized zirconia (3Y-TZP) powders via coprecipitation route, (2) to obtain zirconia ceramic specimens, analyze surface characteristics, and mechanical properties, and (3) to compare the processed material with three reinforced dental ceramics. A coprecipitation route was used to synthesize a 3mol% yttria-stabilized zirconia ceramic processed by uniaxial compaction and pressureless sintering. Commercially available alumina or alumina/zirconia ceramics, namely Procera AllCeram (PA), In-Ceram Zirconia Block (CAZ) and In-Ceram Zirconia (IZ) were chosen for comparison. All specimens (6mmx5mmx5mm) were polished and ultrasonically cleaned. Qualitative phase analysis was performed by XRD and apparent densities were measured on the basis of Archimedes principle. Ceramics were also characterized using SEM, TEM and EDS. The hardness measurements were made employing Vickers hardness test. Fracture toughness (K(IC)) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (alpha=0.05). ANOVA revealed that the Vickers hardness (pceramic materials composition. It was confirmed that the PA ceramic was constituted of a rhombohedral alumina matrix, so-called alpha-alumina. Both CAZ and IZ ceramics presented tetragonal zirconia and alpha-alumina mixture of phases. The SEM/EDS analysis confirmed the presence of aluminum in PA ceramic. In the IZ and CAZ ceramics aluminum, zirconium and cerium in grains involved by a second phase containing aluminum, silicon and lanthanum were identified. PA showed significantly higher mean Vickers hardness values (H(V)) (18.4+/-0.5GPa) compared to vitreous CAZ (10.3+/-0.2GPa) and IZ (10.6+/-0.4GPa) ceramics. Experimental Y-TZP showed significantly lower results than that of the other monophased ceramic (PA) (pceramics (pceramic processing conditions led to ceramics with mechanical properties comparable to commercially available reinforced ceramic materials.

  2. Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration

    NARCIS (Netherlands)

    Sanchez, L.D.; Marin, L.M.; Visscher, J.T.; Rietveld, L.C.

    2012-01-01

    This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF) in a multi-stage filtration (MSF) plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It s

  3. Dynamic optimization of a dead-end filtration trajectory : Non-ideal cake filtration

    NARCIS (Netherlands)

    Blankert, Bastiaan; Kattenbelt, Carolien; Betlem, Ben H.L.; Roffel, Brian

    2007-01-01

    A control strategy aimed at minimizing energy consumption is formulated for non-ideal dead-end cake filtration with an inside-out hollow fiber ultrafiltration membrane system. The non-ideal behavior was assumed to originate from cake compression, non-linear cake resistance and a variable pump effici

  4. Dynamic optimization of a dead-end filtration trajectory : Blocking filtration laws

    NARCIS (Netherlands)

    Blankert, Bastiaan; Betlem, Ben H.L.; Roffel, Brian

    2006-01-01

    An operating model for dead-end membrane filtration is proposed based on the well-known blocking laws. The resulting model contains three parameters representing, the operating strategy, the fouling mechanism and the fouling potential of the feed. The optimal control strategy is determined by minimi

  5. Speciation analysis of 129I in seawater using coprecipitation and accelerator mass spectrometry and its applications

    DEFF Research Database (Denmark)

    Xing, Shan; Hou, Xiaolin; Aldahan, Ala

    2017-01-01

    Speciation analysis of long-lived 129I in seawater can provide useful information on the source of water masses. This paper presents an improved method for speciation analysis of 129I based on coprecipitation of iodide as AgI with Ag2SO3 and AgCl. By adding a small amount of 127I carrier, the sep...

  6. Phosphorus removal from municipal wastewater by hydrous ferric oxide reactive filtration and coupled chemically enhanced secondary treatment: part II--mechanism.

    Science.gov (United States)

    Newcombe, R L; Strawn, D G; Grant, T M; Childers, S E; Möller, G

    2008-03-01

    The removal mechanism of a hydrous ferric oxide (HFO) reactive filtration (RF) process with coupled chemically enhanced secondary treatment (RECYCLE) for phosphorus removal from municipal wastewater (HFO-RF-RECYCLE) was examined. A 0.95-ML/d (0.25-mgd) demonstration of HFO-RF-RECYCLE was performed at a municipal wastewater treatment plant equipped with oxidation ditches and secondary clarifiers. Influent to the plant averaged 6.0 mg/L phosphorus, with a 3-month tertiary effluent average of 0.011 mg/L phosphorus. In addition to aqueous geochemical modeling, experiments with surface charge, scanning electron microscopy, adsorptive capacity, thermal desorption, and most probable number of iron(III)-reducing bacteria were performed on samples from the system, to determine the major phosphorus-removal pathways. Results suggest that, in addition to filtration of particulate phosphorus, the low tertiary effluent total phosphorus result was achieved by adsorption.

  7. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  8. METC CFD simulations of hot gas filtration

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, T.J.

    1995-06-01

    Computational Fluid Dynamic (CFD) simulations of the fluid/particle flow in several hot gas filtration vessels will be presented. These simulations have been useful in designing filtration vessels and in diagnosing problems with filter operation. The simulations were performed using the commercial code FLUENT and the METC-developed code MFIX. Simulations of the initial configuration of the Karhula facility indicated that the dirty gas flow over the filter assemblage was very non-uniform. The force of the dirty gas inlet flow was inducing a large circulation pattern that caused flow around the candles to be in opposite directions on opposite sides of the vessel. By introducing a system of baffles, a more uniform flow pattern was developed. This modification may have contributed to the success of the project. Several simulations of configurations proposed by Industrial Filter and Pump were performed, varying the position of the inlet. A detailed resolution of the geometry of the candles allowed determination of the flow between the individual candles. Recent simulations in support of the METC/CeraMem Cooperative Research and Development Agreement have analyzed the flow in the vessel during the cleaning back-pulse. Visualization of experiments at the CeraMem cold-flow facility provided confidence in the use of CFD. Extensive simulations were then performed to assist in the design of the hot test facility being built by Ahlstrom/Pyropower. These tests are intended to demonstrate the CeraMem technology.

  9. Diatomite releases silica during spirit filtration.

    Science.gov (United States)

    Gómez, J; Gil, M L A; de la Rosa-Fox, N; Alguacil, M

    2014-09-15

    The purpose of this study was to ascertain whether diatomite is an inert filter aid during spirit filtration. Surely, any compound with a negative effect on the spirit composition or the consumer's health could be dissolved. In this study different diatomites were treated with 36% vol. ethanol/water mixtures and the amounts and structures of the extracted compounds were determined. Furthermore, Brandy de Jerez was diatomite- and membrane-filtered at different temperatures and the silicon content was analysed. It was found that up to 0.36% by weight of diatomite dissolved in the aqueous ethanol and amorphous silica, in the form of hollow spherical microparticles, was the most abundant component. Silicon concentrations in Brandy de Jerez increased by up to 163.0% after contact with diatomite and these changes were more marked for calcined diatomite. In contrast, reductions of more than 30% in silicon concentrations were achieved after membrane filtration at low temperatures. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Tailoring Supramolecular Nanofibers for Air Filtration Applications.

    Science.gov (United States)

    Weiss, Daniel; Skrybeck, Dominik; Misslitz, Holger; Nardini, David; Kern, Alexander; Kreger, Klaus; Schmidt, Hans-Werner

    2016-06-15

    The demand of new materials and processes for nanofiber fabrication to enhance the performance of air filters is steadily increasing. Typical approaches to obtain nanofibers are based on top-down processes such as melt blowing, centrifugal spinning, and electrospinning of polymer materials. However, fabrication of polymer nanofibers is limited with respect to either a sufficiently high throughput or the smallest achievable fiber diameter. This study reports comprehensively on a fast and simple bottom-up process to prepare supramolecular nanofibers in situ inside viscose/polyester microfiber nonwovens. Here, selected small molecules of the materials class of 1,3,5-benzenetrisamides are employed. The microfiber-nanofiber composites exhibit a homogeneous nanofiber distribution and morphology throughout the entire nonwoven scaffold. Small changes in molecular structure and processing solvent have a strong influence on the final nanofiber diameter and diameter distribution and, consequently, on the filtration performance. Choosing proper processing conditions, microfiber-nanofiber composites with surprisingly high filtration efficiencies of particulate matter are obtained. In addition, the microfiber-nanofiber composite integrity at elevated temperatures was determined and revealed that the morphology of supramolecular nanofibers is maintained compared to that of the utilized polymer nonwoven.

  11. Renal filtration function in patients with gout

    Directory of Open Access Journals (Sweden)

    N. N. Kushnarenko

    2016-01-01

    Full Text Available Aim. To study circadian blood pressure (BP profile in patients with gout depending on the presence of arterial hypertension (HT and their relationship to the renal filtration function.Material and methods. Patients with gout (n=87 were included into the study. All the patients underwent ambulatory BP monitoring (ABPM with the assessment of circadian BP profile, determination of uric acid serum levels, glomerular filtration rate (GFR was evaluated by CKD-EPI method. Depending on GFR level, all the patients were divided into 2 groups - with renal dysfunction or without one.Results. ABPM revealed circadian BP dysregulation in 55% of gout patients both with HT and without HT. Chronic kidney disease (CKD was revealed in 72.4% of male patients, with the prevalence in patients with HT (76.6 vs 61%; p<0.001. Correlations between uric acid levels and some ABPM indicators and GFR were determined.Conclusion. Obtained data suggest the contribution of hyperuricemia in disorders of systemic and renal hemodynamics, leading to the early development of CKD.

  12. Riverbed Clogging and Sustainability of Riverbank Filtration

    Directory of Open Access Journals (Sweden)

    Thomas Grischek

    2016-12-01

    Full Text Available Clogging refers to a reduction of riverbed hydraulic conductivity. Due to difficulties in determining the thickness of the clogging layer, the leakage coefficient (L is introduced and used to quantify the recoverable portion of bank filtrate. L was determined at several riverbank filtration (RBF sites in field tests and using an analytical solution. Results were compared with data from similar experiments in the early 1970s and 1991–1993. In the 1980s, severe river water pollution in conjunction with high water abstraction led to partly unsaturated conditions beneath the riverbed. A leakage coefficient L of 5 × 10−7 s−1 was determined. After water quality improvement, L increased to 1–1.5 × 10−6 s−1. An alternative, cost and time efficient method is presented to estimate accurate leakage coefficients. The analytical solution is based on groundwater level monitoring data from observation wells next to the river, which can later feed into numerical models. The analytical approach was able to reflect long-term changes as well as seasonal variations. Recommendations for its application are given based on experience.

  13. Magnetic Graphene Oxide: Effect of Preparation Route on Reactive Black 5 Adsorption

    Directory of Open Access Journals (Sweden)

    Orestis Kalogirou

    2013-03-01

    Full Text Available In this study, the effect of preparation route of magnetic graphene oxide (mGO on Reactive Black 5 (RB5 adsorption was investigated. The synthesis of mGO was achieved both with (i impregnation method (mGOi nanoparticles, and (ii co-precipitation (mGOp nanoparticles. After synthesis, the full characterization with various techniques (SEM, FTIR, XRD, DTA, DTG, VSM was achieved revealing many possible interactions/forces of dye-composite system. Effects of initial solution pH, effect of temperature, adsorption isotherms and kinetics were investigated in order to conclude about the aforementioned effect of the preparation method on dye adsorption performance of the magnetic nanocomposites. The adsorption evaluation of the magnetic nanoparticles presented higher adsorption capacity of mGOp derivative (188 mg/g and lower of mGOi (164 mg/g. Equilibrium experiments are also performed studying the effect of contact time (pseudo-first and -second order equations and temperature (isotherms at 25, 45 and 65 °C fitted to Langmuir and Freundlich model. A full thermodynamic evaluation was carried out, calculating the parameters of enthalpy, free energy and entropy (ΔH0, ΔG0 and ΔS0.

  14. A study of dynamic filtration; Um estudo sobre filtracao dinamica

    Energy Technology Data Exchange (ETDEWEB)

    Girao, Joaquim Helder S. [PETROBRAS, Natal, RN (Brazil). Distrito de Perfuracao da Bacia Potiguar. Div. de Tecnicas de Perfuracao

    1989-12-31

    The problems that cause cost increase such as: formation damage and borehole swelling or caving lead us to study the filtration of the liquid part of formation drilling fluid. With the aim of comparing static and dynamic filtration rates, we developed a modest dynamic filtration equipment, consisting of a modified API filter, connected to reservoir by means of a positive injection pump. We carried out various tests, and the results were set in charts and tables. Through these, it is possible to notice how the static and dynamic filtration curves come apart for a same pressure value. We also evaluated the effects of circulation speed, starch concentration and counter pressure. This paper does not include calculations or mathematical models accounting for filtrate invasion radii, but it demonstrates, for example, that cleaning circulation will cause lower filtration rates at lower flows. (author) 5 refs., 11 figs., 14 tabs.

  15. Physicochemical interaction and its influence on deep bed filtration process.

    Science.gov (United States)

    Guo, Jin-long; Meng, Jun; Li, Gui-ping; Luan, Zhao-kun; Tang, Hong-xiao

    2004-01-01

    The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. The physicochemical interaction forces between the filter media and suspended particles and their influence on deep bed filtration process were also studied theoretically. Through the comparison of the hydraulic and physicochemical forces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the microflocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and the experimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoretical prediction was reasonably consistent with the experimental results under different conditions, which indicated that the regulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of the physicochemical interactions. Further theoretical and experimental research should be carried out to investigate the interaction mechanism and its application in the deep bed filtration and other cases.

  16. In-Water Hull Cleaning & Filtration System

    Science.gov (United States)

    George, Dan

    2015-04-01

    Dan George R & D Mining Technology LinkedIn GRD Franmarine have received the following prestigious awards in 2014 for their research & development of an in-water hull cleaning and filtration system "The Envirocart: Golden Gecko Award for Environmental Excellence; WA Innovator of the Year - Growth Sector; Department of Fisheries - Excellence in Marine Biosecurity Award - Innovation Category; Lloyd's List Asia Awards - Environmental Award; The Australian Innovation Challenge - Environment, Agriculture and Food Category; and Australian Shipping and Maritime Industry Award - Environmental Transport Award. The Envirocart developed and patented by GRD Franmarine is a revolutionary new fully enclosed capture and containment in-water hull cleaning technology. The Envirocart enables soft Silicon based antifouling paints and coatings containing pesticides such as Copper Oxide to be cleaned in situ using a contactless cleaning method. This fully containerised system is now capable of being deployed to remote locations or directly onto a Dive Support Vessel and is rated to offshore specifications. This is the only known method of in-water hull cleaning that complies with the Department of Agriculture Fisheries and Forestry (DAFF) and Department of Fisheries WA (DoF) Guidelines. The primary underwater cleaning tool is a hydraulically powered hull cleaning unit fitted with rotating discs. The discs can be fitted with conventional brushes for glass or epoxy based coatings or a revolutionary new patented blade system which can remove marine biofouling without damaging the antifouling paint (silicone and copper oxide). Additionally there are a patented range of fully enclosed hand cleaning tools for difficult to access niche areas such as anodes and sea chests, providing an innovative total solution that enables in-water cleaning to be conducted in a manner that causes no biological risk to the environment. In full containment mode or when AIS are present, material is pumped

  17. The effect of filter cake viscoelasticity on filtration

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard

    Wastewater is usually treated biologically, and a by-product from this treatment is waste-activated sludge with high water content. Sludge is therefore often filtrated to reduce the volume for handling and disposal, and to minimise the water content before incineration of the sludge. However...... a function of pressure as assumed when using the conventional models. Moreover, it is shown how the existing filtration models can be modified and the filtration process for activated sludge simulated....

  18. Analysis of fouling development under dynamic membrane filtration operation

    OpenAIRE

    Saleem, Mubashir; Alibardi, Luca; Cossu, Raffaello; Lavagnolo, Maria Cristina; Spagni, Alessandro

    2016-01-01

    This research is a contribution towards evaluating the appropriate fouling mechanism responsible for the flux decline under dynamic membrane (DM) filtration and its formation mechanism by using gravity-driven filtration in a specifically designed experimental setup. Series of extended short term filtration experiments were performed at varying operating conditions of mixed liquor suspended solids (MLSS) concentrations, trans-membrane pressures (TMP) and mesh pore sizes. Blocking models were a...

  19. Removal of cytomegalovirus DNA from donor blood by filtration.

    Science.gov (United States)

    Smith, K L; Cobain, T; Dunstan, R A

    1993-04-01

    Blood from five donors, previously shown to be positive for cytomegalovirus (CMV) DNA following polymerase chain reaction (PCR) amplification, was filtered through commercially available leucocyte filters. Analysis of pre- and post-filtration samples by PCR with ethidium bromide staining has shown that filtration was successful in removing CMV DNA from all samples. This is evidence that leucocyte filtration of red cell concentrates may greatly decrease the risk of CMV disease following transfusion to susceptible patients.

  20. Carrier element-free coprecipitation (CEFC) method for the separation, preconcentration and speciation of chromium using an isatin derivative

    Energy Technology Data Exchange (ETDEWEB)

    Bulut, Volkan Numan; Ozdes, Duygu; Bekircan, Olcay; Gundogdu, Ali; Duran, Celal [Department of Chemistry, Karadeniz Technical University, Faculty of Arts and Sciences, 61080 Trabzon (Turkey); Soylak, Mustafa [Department of Chemistry, Erciyes University, Faculty of Arts and Sciences, 38039 Kayseri (Turkey)], E-mail: soylak@erciyes.edu.tr

    2009-01-19

    A new, simple, rapid and sensitive separation, preconcentration and speciation procedure for chromium in environmental liquid and solid samples has been established. The present speciation procedure for Cr(III) and Cr(VI) is based on combination of carrier element-free coprecipitation (CEFC) and flame atomic absorption spectrometric (FAAS) determinations. In this method a newly synthesized organic coprecipitant, 5-chloro-3-[4-(trifluoromethoxy) phenylimino]indolin-2-one (CFMEPI), was used without adding any carrier element for coprecipitation of chromium(III). After reduction of chromium(VI) by concentrated H{sub 2}SO{sub 4} and ethanol, the procedure was applied for the determination of total chromium. Chromium(VI) was calculated as the difference between the amount of total chromium and chromium(III). The optimum conditions for coprecipitation and speciation processes were investigated on several commonly tested experimental parameters, such as pH of the solution, amount of coprecipitant, sample volume, etc. No considerable interference was observed from the other investigated anions and cations, which may be found in natural water samples. The preconcentration factor was found to be 40. The detection limit for chromium(III) corresponding to three times the standard deviation of the blank (N = 10) was found 0.7 {mu}g L{sup -1}. The present procedure was successfully applied for speciation of chromium in several liquid and solid environmental samples. In order to support the accuracy of the method, the certified reference materials (CRM-TMDW-500 Drinking Water and CRM-SA-C Sandy Soil C) were analyzed, and standard APDC-MIBK liquid-liquid extraction method was performed. The results obtained were in good agreement with the certified values.

  1. Filtration of triazine herbicides by polymer-clay sorbents: coupling an experimental mechanistic approach with empirical modeling.

    Science.gov (United States)

    Gardi, Ido; Nir, Shlomo; Mishael, Yael G

    2015-03-01

    Triazine herbicides detected in surface and groundwater pose environmental and health risks. Removal of triazine herbicides (simazine, atrazine and terbuthylazine) by polymer-clay composites was studied and modeled. Their binding by a poly 4-vinyl pyridine co styrene-montmorillonite (HPVP-CoS-MMT) composite was especially high due to specific interactions between the herbicides and polymer, mainly hydrogen bonds and π-π stacking. The binding kinetics to the composite was in the order of simazine > atrazine > terbuthylazine, which was in accord with their equilibrium Langmuir binding coefficients; 44,000, 17,500 and 16,500 M(-1), respectively, which correlated with herbicide accessibility to form specific interaction with the polymer. Simazine binding kinetics to the composite was significantly faster than to granulated activated carbon (GAC), reaching 93% vs 38% of the maximal adsorption within 10 min, respectively. Herbicide filtration by composite columns was adequately fitted by a model which considers convection and employs Langmuir formalism for kinetics of adsorption/desorption. Filtration of simazine (10 μg L(-1)) by composite columns (40 cm long, which included 26 g composite mixed with sand 1:40 (weight ratio)), was well predicted by the model with nearly 120 L purified, i.e., effluent concentrations were below regulation limit (3 μg L(-1)). Effluent concentrations from GAC columns exceeded the limit after filtering 5 L. Experimental results and model predictions suggest that while GAC has a high capacity for simazine binding, the composite has higher affinity towards the herbicide and its adsorption is faster, which yields more efficient filtration by composite columns.

  2. Phosphate adsorption performance of a novel filter substrate made from drinking water treatment residuals.

    Science.gov (United States)

    Wang, Wendong; Ma, Cui; Zhang, Yinting; Yang, Shengjiong; Shao, Yue; Wang, Xiaochang

    2016-07-01

    Phosphate is one of the most predominant pollutants in natural waters. Laboratory experiments were conducted to investigate the phosphate adsorption performance of a (NFS) made from drinking water treatment residuals. The adsorption of phosphate on the NFS fitted well with the Freundlich isotherm and pseudo second-order kinetic models. At pH7.0, the maximum adsorption capacity of 1.03mg/g was achieved at 15°C corresponding to the wastewater temperature in cold months, and increased notably to 1.31mg/g at 35°C. Under both acidic conditions (part of the adsorption sites was consumed) and basic conditions (negative charges formed on the surface of NFS, which led to a static repulsion of PO4(3-) and HPO4(2-)), the adsorption of phosphate was slightly inhibited. Further study showed that part of the adsorption sites could be recovered by 0.25mol/L NaOH. The activation energy was calculated to be above 8.0kJ/mol, indicating that the adsorption of phosphate on NFS was probably a chemical process. Considering the strong phosphate adsorption capacity and recoverability, NFS showed great promise on enhancing phosphate removal from the secondary treated wastewater in the filtration process. Copyright © 2016. Published by Elsevier B.V.

  3. Random sequential adsorption of human adenovirus 2 onto polyvinylidene fluoride surface influenced by extracellular polymeric substances.

    Science.gov (United States)

    Lu, Ruiqing; Li, Qi; Nguyen, Thanh H

    2016-03-15

    Virus removal by membrane bioreactors depends on virus-membrane and virus-foulant interactions. The adsorption of human adenovirus 2 (HAdV-2) on polyvinylidene fluoride (PVDF) membrane and a major membrane foulant, extracellular polymeric substances (EPS), were measured in a quartz crystal microbalance. In 3-100mM CaCl2 solutions, irreversible adsorption of HAdV-2 was observed on both pristine and EPS-fouled PVDF surfaces. The HAdV-2 adsorption kinetics was successfully fitted with the random sequential adsorption (RSA) model. The applicability of the RSA model for HAdV-2 adsorption is confirmed by comparing the two fitting parameters, adsorption rate constant k(a) and area occupied by each adsorbed HAdV-2 particle a, with experimentally measured parameters. A linear correlation between the fitting parameter k(a) and the measured attachment efficiency was found, suggesting that the RSA model correctly describes the interaction forces dominating the HAdV-2 adsorption. By comparing the fitting parameter d(ads) with the hydrodynamic diameter of HAdV-2, we conclude that virus-virus and virus-surface interactions determine the area occupied by each adsorbed HAdV-2 particle, and thus influence the adsorption capacity. These results provide insights into virus retention and will benefit improving virus removal in membrane filtration.

  4. Membraneless water filtration using CO2

    Science.gov (United States)

    Shin, Sangwoo; Shardt, Orest; Warren, Patrick; Stone, Howard

    2016-11-01

    Water purification technologies such as ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal suspension to CO2. Dissolution of CO2 into the suspension creates solute gradients that drive phoretic motion of particles, or so-called diffusiophoresis. Due to the large diffusion potential built up by the dissociation of carbonic acid, colloidal particles move either away from or towards the gas-liquid interface depending on their surface charge. Our findings suggest a means to separate particles without membranes or filters, thus reducing operating and maintenance costs. Using the directed motion of particles induced by exposure to CO2, we demonstrate a scalable, continuous flow, membraneless particle filtration process that exhibits very low pressure drop and is essentially free from fouling.

  5. Dynamical Systems, Cytokine Storms, and Blood Filtration

    Science.gov (United States)

    Foster, Glenn; Hubler, Alfred

    2008-03-01

    Various infections and non-infectious diseases can trigger immune cells and the proteins (cytokines) the cells use to communicate with each other to be caught in a positive feedback loop; this ``cytokine storm'' is frequently fatal. By examining the network of cytokine-immune cell interactions we will illustrate why anti-mediator drugs have been generally ineffective in stopping this feedback. A more effective approach may be to try and reduce interactions by dampening many signals at once by filtering the cytokines out of the blood directly (think dialysis). We will argue that feedback on an out of control nonlinear dynamical system is easier to understand than its normal healthy state and apply filtration to a toy model of immune response.

  6. Pattern recognition using inverse resonance filtration

    CERN Document Server

    Sofina, Olga; Kvetnyy, Roman

    2010-01-01

    An approach to textures pattern recognition based on inverse resonance filtration (IRF) is considered. A set of principal resonance harmonics of textured image signal fluctuations eigen harmonic decomposition (EHD) is used for the IRF design. It was shown that EHD is invariant to textured image linear shift. The recognition of texture is made by transfer of its signal into unstructured signal which simple statistical parameters can be used for texture pattern recognition. Anomalous variations of this signal point on foreign objects. Two methods of 2D EHD parameters estimation are considered with the account of texture signal breaks presence. The first method is based on the linear symmetry model that is not sensitive to signal phase jumps. The condition of characteristic polynomial symmetry provides the model stationarity and periodicity. Second method is based on the eigenvalues problem of matrices pencil projection into principal vectors space of singular values decomposition (SVD) of 2D correlation matrix....

  7. Gravity filtration of suspensions: permeability effects

    Science.gov (United States)

    Soori, Tejaswi; Wang, Mengyu; Ward, Thomas

    2015-11-01

    This paper examines the filtration rates of mono-modal suspensions as a function of time and a cake layer builds up through theory and experimentation. Darcy's Law, which describes fluid flow through porous media, was applied along with the Kynch theory of sedimentation, which provides the basis for analyzing low concentration (ϕ filter media. A CCD camera was used to capture images of the cake formation and fluid drainage processes, and subsequent image and theoretical analysis found the fluid flow experienced a constant pressure loss due to the permeability of the filter media, whereas the experienced pressure loss due to the cake formation varies as a function of time, ϕ and d. The rate of cake formation was also found to be independent of ϕ but dependent on d which can be attributed to a change in porosity affecting permeability. Studies on similar systems with multi-modal suspensions are in-progress.

  8. Facile and green fabrication of cellulosed based aerogels for lampblack filtration from waste newspaper.

    Science.gov (United States)

    Fan, Peidong; Yuan, Yali; Ren, Junkai; Yuan, Bin; He, Qian; Xia, Guangmei; Chen, Fengxia; Song, Rui

    2017-04-15

    In this study, the lightweight, hydrophobic and porous cellulose-based aerogels (CAGs) were synthesized through a freeze-drying process using waste newspaper as the only raw material. After crosslinking with glutaraldehyde and treatment with trimethylchlorosilane (TMCS) using a simple thermal chemical vapor deposition process, the resulting CAGs became hydrophobic and oleophilic. Furthermore, the as-prepared CAGs exhibited a low density (17.4-28.7mgcm(-3)) and mesoporous inner-structure. All these properties attributed the novel aerogel not only with a good adsorption capability of oils and organic solvents, including kerosene, nitrobenzene, and chloroform, but also an excellent filtration capacity of lampblack. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. RhB Adsorption Performance of Magnetic Adsorbent Fe3O4/RGO Composite and Its Regeneration through A Fenton-like Reaction

    Institute of Scientific and Technical Information of China (English)

    Yalin Qin; Mingce Long∗; Beihui Tan; Baoxue Zhou

    2014-01-01

    Adsorption is one of the most effective technologies in the treatment of colored matter containing wastewater. Graphene related composites display potential to be an effective adsorbent. However, the adsorp-tion mechanism and their regeneration approach are still demanding more efforts. An effective magnetically separable absorbent, Fe3O4 and reduced graphene oxide (RGO) composite has been prepared by an in situ coprecipitation and reduction method. According to the characterizations of TEM, XRD, XPS, Raman spectra and BET analyses, Fe3O4 nanoparticles in sizes of 10-20 nm are well dispersed over the RGO nanosheets, re-sulting in a highest specific area of 296.2 m2/g. The rhodamine B adsorption mechanism on the composites was investigated by the adsorption kinetics and isotherms. The isotherms are fitting better by Langmuir model, and the adsorption kinetic rates depend much on the chemical components of RGO. Compared to active carbon, the composite shows 3.7 times higher adsorption capacity and thirty times faster adsorption rates. Furthermore, with Fe3O4 nanoparticles as the in situ catalysts, the adsorption performance of composites can be restored by carrying out a Fenton-like reaction, which could be a promising regeneration way for the adsorbents in the organic pollutant removal of wastewater.

  10. Modeling Adsorption Kinetics (Bio-remediation of Heavy Metal Contaminated Water)

    Science.gov (United States)

    McCarthy, Chris

    My talk will focus on modeling the kinetics of the adsorption and filtering process using differential equations, stochastic methods, and recursive functions. The models have been developed in support of our interdisciplinary lab group which is conducting research into bio-remediation of heavy metal contaminated water via filtration through biomass such as spent tea leaves. The spent tea leaves are available in large quantities as a result of the industrial production of tea beverages. The heavy metals bond with the surfaces of the tea leaves (adsorption). Funding: CUNY Collaborative Incentive Research Grant.

  11. Structural and magnetic properties of holmium substituted cobalt ferrites synthesized by chemical co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Irshad; Islam, M.U.; Ishaque, M.; Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan (Pakistan); Naeem Ashiq, Muhammad, E-mail: naeemashiqqau@yahoo.com [Department of Chemistry, Bahauddin Zakariya University, Multan (Pakistan); Rana, M.U. [Department of Physics, Bahauddin Zakariya University, Multan (Pakistan)

    2012-11-15

    CoHo{sub x}Fe{sub 2-x}O{sub 4} ferrites (x=0.00-0.1) were prepared by the co-precipitation technique and the effect of holmium substitution on the magnetic properties was investigated. X-ray diffraction reveals that the substituted samples show a second phase of HoFeO{sub 3} along with the spinel phase. The magnetic properties such as the saturation magnetization (M{sub s}), coercivity (H{sub c}) and remanence (M{sub r}) are obtained from the hysteresis loops. It is observed that the M{sub s} decreases while H{sub c} increases with Ho{sup 3+} substitution. The decrease of saturation magnetization is attributed to the weakening of exchange interactions. The coercivity increases with increase of the Ho{sup 3+} concentration, which is attributed to the presence of an ultra-thin layer at the grain boundaries that impedes the domain wall motion. Low field AC susceptibility was also measured over the temperature range 300-600 K at the frequency of 200 Hz. It decreases with the increase of temperature following the Curie-Weiss law up to the Curie temperature. Above the Curie temperature it shows paramagnetic behavior. The increase in coercivity suggests that the material can be used for applications in perpendicular recording media. - Highlights: Black-Right-Pointing-Pointer CoHo{sub x}Fe{sub 2-x}O{sub 4} ferrites (x=0.00, 0.04, 0.06, 0.08, 1.0) were prepared by the simple and economic co-precipitation technique. Black-Right-Pointing-Pointer X-ray diffraction reveals that the samples are biphasic except for the undoped sample. Black-Right-Pointing-Pointer Decrease in saturation magnetization is attributed to the weakening of the exchange interactions. Black-Right-Pointing-Pointer Coercivity increases with increase of the Ho{sup 3+} concentration. Black-Right-Pointing-Pointer Increase in coercivity suggests that the materials can be used for applications in perpendicular recording media.

  12. Some aspects of applying nanostructured materials in air filtration, water filtration and electrical engineering

    Science.gov (United States)

    Kimmer, Dusan; Vincent, Ivo; Lovecka, Lenka; Kazda, Tomas; Giurg, Adam; Skorvan, Ondrej

    2017-05-01

    Nanostructures prepared from nanofibres and nanostructured composites prepared from nanofibres and fillers are gradually becoming increasingly demanded materials for applications in various industrial branches connected with catalysis, environment protection (air filtration, waste water treatment, sound absorption), in biological engineering, electronics (battery separators, electrode materials), etc. Selected applications of these materials prepared in the company SPUR a.s. are summed up in the following presentation.

  13. Life Support Filtration System Trade Study for Deep Space Missions

    Science.gov (United States)

    Agui, Juan H.; Perry, Jay L.

    2017-01-01

    The National Aeronautics and Space Administrations (NASA) technical developments for highly reliable life support systems aim to maximize the viability of long duration deep space missions. Among the life support system functions, airborne particulate matter filtration is a significant driver of launch mass because of the large geometry required to provide adequate filtration performance and because of the number of replacement filters needed to a sustain a mission. A trade analysis incorporating various launch, operational and maintenance parameters was conducted to investigate the trade-offs between the various particulate matter filtration configurations. In addition to typical launch parameters such as mass, volume and power, the amount of crew time dedicated to system maintenance becomes an increasingly crucial factor for long duration missions. The trade analysis evaluated these parameters for conventional particulate matter filtration technologies and a new multi-stage particulate matter filtration system under development by NASAs Glenn Research Center. The multi-stage filtration system features modular components that allow for physical configuration flexibility. Specifically, the filtration system components can be configured in distributed, centralized, and hybrid physical layouts that can result in considerable mass savings compared to conventional particulate matter filtration technologies. The trade analysis results are presented and implications for future transit and surface missions are discussed.

  14. Vibrating membrane filtration as improved technology for microalgae dewatering.

    Science.gov (United States)

    Nurra, Claudia; Clavero, Ester; Salvadó, Joan; Torras, Carles

    2014-04-01

    The effect of shear-enhanced filtration by vibratory process in microalgae dewatering is presented in this paper. The aim of this research was to investigate the technical performance and improvement of vibrating membrane filtration compared with conventional tangential cross-flow filtration in microalgae concentration. An industrial-scale available commercial set-up was used. Several membrane materials as polyethersulfone, polyacrylonitrile, etc., and mean pore sizes (from 7000Da to 0.2μm) were tested and compared in both filtration set-ups. Experiments were carried-out with Nannochloropsis gaditana and Phaeodactylum tricornutum microalgae. It has been demonstrated that, even if the choice of the membrane depends on its cut-off, its material and the type of microalgae filtrated, dynamic filtration is always the best technology over a conventional one. If with conventional filtration permeability values were in the vicinity of 10L/h/m(2)/bar in steady state phase, with dynamic filtration these values increased to 30L/h/m(2)/bar or more.

  15. Analysis of the Medium Resistance for Constant Pressure Filtration

    Institute of Scientific and Technical Information of China (English)

    吴燕翔; 王碧玉

    2004-01-01

    A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the suppositional filtration time Ore. It is demonstrated that Rm is nearly a constant for a given filter cloth.

  16. Purification of contaminated water by filtration through porous glass

    Science.gov (United States)

    Wydeven, T.; Leban, M. I.

    1972-01-01

    Method for purifying water that is contaminated with mineral salts and soluble organic compounds is described. Method consists of high pressure filtration of contaminated water through stabilized porous glass membranes. Procedure for conducting filtration is described. Types of materials by percentage amounts removed from the water are identified.

  17. Filter aids influence on pressure drop across a filtration system

    Science.gov (United States)

    Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

    2017-06-01

    Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

  18. Scaling and particulate fouling in membrane filtration systems

    NARCIS (Netherlands)

    Boerlage, S.F.E.

    2001-01-01

    In the last decade, pressure driven membrane filtration processes; reverse osmosis, nano, ultra and micro-filtration have undergone steady growth. Drivers for this growth include desalination to combat water scarcity and the removal of various material from water to comply with increasingly stringen

  19. Scaling and particulate fouling in membrane filtration systems

    NARCIS (Netherlands)

    Boerlage, S.F.E.

    2001-01-01

    In the last decade, pressure driven membrane filtration processes; reverse osmosis, nano, ultra and micro-filtration have undergone steady growth. Drivers for this growth include desalination to combat water scarcity and the removal of various material from water to comply with increasingly

  20. Simulation of impaction filtration by a porous filter

    NARCIS (Netherlands)

    Ghazaryan, L.; Lopez Penha, D.J.; Geurts, B.J.; Stolz, S.; Winkelmann, C.; Vafai, K.

    2010-01-01

    We present a new numerical approach for estimating filtration through porous media from first principles. We numerically simulate particle motion as arises in a carrier gas flow. The filtration we look at occurs due to impaction of particles with obstructing surfaces that are contained in the solid

  1. Model and optimization of electromagnetic filtration of metals

    Directory of Open Access Journals (Sweden)

    S. Golak

    2013-04-01

    Full Text Available Electromagnetic buoyancy force causes the movement of non-conducive particles in a conducting liquid under electromagnetic field. The phenomenon allows filtration of small inclusions from molten metals. This paper presents a mathematical model of the filtration process under alternating electromagnetic field and the methodology for maximizing its efficiency.

  2. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon

    2013-12-26

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  3. Comparative Study on the Adsorption of [AuCl4]– onto Salicylic Acid and Gallic Acid Modified Magnetite Particles

    OpenAIRE

    Rahmayanti, Maya; Santosa, Sri Juari; Sutarno, Sutarno

    2016-01-01

    Salicylic acid-modified magnetite (Mag-SA) and gallic acid-modified magnetite (Mag-GA) particles were prepared by co-precipitation procedure. Characterization results showed the interaction that occurs between the surface of magnetite with salicylic acid (Mag-SA) and gallic acid (Mag-GA) was through hydrogen bonding. Adsorption of [AuCl4]– onto Mag-SA and Mag-GA surfaces as a function of initial pH, contact time, and initial concentration of the [AuCl4]– solution were comparatively investigat...

  4. Adsorption studies of chromium (VI) removal from water by lanthanum diethanolamine hybrid material.

    Science.gov (United States)

    Mandal, Sandip; Sahu, Manoj Kumar; Giri, Anil Kumar; Patel, Raj Kishore

    2014-01-01

    In the present research work, lanthanum diethanolamine hybrid material is synthesized by co-precipitation method and used for the removal of Cr(VI) from synthetic dichromate solution and hand pump water sample. The sorption experiments were carried out in batch mode to optimize various influencing parameters such as adsorbent dose, contact time, pH, competitive anions and temperature. The characterization of the material and mechanism of Cr(VI) adsorption on the material was studied by using scanning electron microscope, Fourier transform infrared, X-ray diffraction, Brunauer-Emmett-Teller and thermogravimetric analysis-differential thermal analysis. Adsorption kinetics studies reveal that the adsorption process followed first-order kinetics and intraparticle diffusion model with correlation coefficients (R2) of 0.96 and 0.97, respectively. The adsorption data were best fitted to linearly transformed Langmuir isotherm with correlation coefficient (R2) of 0.997. The maximum removal of Cr(VI) is found to be 99.31% at optimal condition: pH = 5.6 of the solution, adsorbent dose of 8 g L(-1) with initial concentration of 10mgL(-1) of Cr(VI) solution and an equilibrium time of 50 min. The maximum adsorption capacity of the material is 357.1 mg g(-1). Thermodynamic parameters were evaluated to study the effect of temperature on the removal process. The study shows that the adsorption process is feasible and endothermic in nature. The value of E (260.6 kJ mol(-1)) indicates the chemisorption nature of the adsorption process. The material is difficult to be regenerated. The above studies indicate that the hybrid material is capable of removing Cr(VI) from water.

  5. Removal of Arsenic from Drinking Water by Adsorption and Coagulation

    Science.gov (United States)

    Zhang, M.; Sugita, H.; Hara, J.; Takahashi, S.

    2013-12-01

    Removal of arsenic from drinking water has been an important issue worldwide, which has attracted greater attentions in recent years especially for supplying safe drinking water in developing countries. Although many kinds of treatment approaches that are available or applicable both in principle and practice, such as adsorption, coagulation, membrane filtration, ion exchange, biological process, electrocoagulation and so on, the first 2 approaches (i.e., adsorption and coagulation) are most promising due to the low-cost, high-efficiency, simplicity of treating systems, and thus can be practically used in developing countries. In this study, a literature survey on water quality in Bangladesh was performed to understand the ranges of arsenic concentration and pH of groundwater in Bangladesh. A series of tests were then organized and performed to investigate the effects of arsenic concentration, arsenic forms, pH, chemical compositions of the materials used for adsorption and coagulation, particle size distribution and treatment time on quality of treated water. The experimental results obtained in the study illustrated that both adsorption and coagulation can be used to effectively reduce the concentrations of either arsenic (V) or arsenic (III) from the contaminated water. Coagulation of arsenic with a magnesium-based material developed in this study can be very effective to remove arsenic, especially arsenic (V), from contaminated water with a concentration of 10 ppm to an undetectable level of 0.002 ppm by ICP analyses. Compared to arsenic (III), arsenic (V) is easier to be removed. The materials used for adsorption and coagulation in this study can remove arsenic (V) up to 9 mg/g and 6 mg/g, and arsenic (III) up to 4 mg/g and 3 mg/g, respectively, depending on test conditions and compositions of the materials being used. The control of pH during treatment can be a challenging technical issue for developing both adsorbent and coagulant. Keywords: Water Treatment

  6. Physicochemical interaction and its influence on deep bed filtration process

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-long; MENG Jun; LI GUI-ping; LUAN Zhao-kun; TANG Hong-xiao

    2004-01-01

    The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. Thephysicochemical interaction forces between the filter media and suspended particles and their influence on deep bedfiltration process were also studied theoretically. Through the comparison of the hydraulic and physicochemicalforces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the micro-flocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and theexperimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoreticalprediction was reasonably consistent with the experimental results under different conditions, which indicated that theregulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of thephysicochemical interactions. Further theoretical and experimental research should be carried out to investigate theinteraction mechanism and its application in the deep bed filtration and other cases.

  7. Filtration Process of the Spiramycin Fermentation Broth

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    This paper presents the effects of acidity and additive pretreatment on the filtering rate and Spiramycin (SPM) concentration in the filter liquor of SPM fermentation broth. The experimental results show that the SPM peak value in filter liquor is obtained at pH 5.5 with either 0.1% methanal or 0.1% BAPE. It is also indicated that there exists a dissolution equilibrium of proteins from the experiment results. The soluble proteins are denatured due to the too high/low acidity and then precipitate. Usually, the amount of soluble proteins reaches its lowest level in pH range of 6.0-6.5. The protein precipitation will, together with other suspended solids particles, contribute to the final SPM concentration in the filter liquor. This paper assumes that the contribution is the result of the adsorption equilibrium of SPM on the surfaces of suspended solids. For a satisfactory explanation, the revised Langmuir adsorption theory was employed and a model was developed.

  8. Syringe filtration methods for examining dissolved and colloidal trace element distributions in remote field locations

    Science.gov (United States)

    Shiller, Alan M.

    2003-01-01

    It is well-established that sampling and sample processing can easily introduce contamination into dissolved trace element samples if precautions are not taken. However, work in remote locations sometimes precludes bringing bulky clean lab equipment into the field and likewise may make timely transport of samples to the lab for processing impossible. Straightforward syringe filtration methods are described here for collecting small quantities (15 mL) of 0.45- and 0.02-microm filtered river water in an uncontaminated manner. These filtration methods take advantage of recent advances in analytical capabilities that require only small amounts of waterfor analysis of a suite of dissolved trace elements. Filter clogging and solute rejection artifacts appear to be minimal, although some adsorption of metals and organics does affect the first approximately 10 mL of water passing through the filters. Overall the methods are clean, easy to use, and provide reproducible representations of the dissolved and colloidal fractions of trace elements in river waters. Furthermore, sample processing materials can be prepared well in advance in a clean lab and transported cleanly and compactly to the field. Application of these methods is illustrated with data from remote locations in the Rocky Mountains and along the Yukon River. Evidence from field flow fractionation suggests that the 0.02-microm filters may provide a practical cutoff to distinguish metals associated with small inorganic and organic complexes from those associated with silicate and oxide colloids.

  9. Screening culture filtrates of fungi for activity against Tylenchulus semipenetrans

    Energy Technology Data Exchange (ETDEWEB)

    Verdejo-Lucas, S.; Viera, A.; Stchigel, A. M.; Sorribas, F. J.

    2009-07-01

    Culture filtrates of 20 fungi isolated from citrus soils were screened for their activity against Tylenchulus semipenetrans in both in vitro and greenhouse tests. The filtrates of Talaromyces cyanescens (isolates 2-4 and 2-5), Paecilomyces lilacinus, Chaetomium robustum, Acremonium strictum, Engyodontium album, Myrothecium verrucaria, Emericella rugulosa, and Tarracomyces gigaspora consistently inhibited the motility of second-stage juveniles at various concentrations of the filtrate. Dose-response models were used to determine the filtrate concentration required to inhibit the motility of 50% of the juveniles (CI50). The culture filtrate of P. lilacinus showed the highest activity with a CI50 value of 58% that differed from that of C. robustum (CI50 = 68%), and A. strictum CI50 = 82%. The culture filtrates of P. lilacinus, E. album, and T. cyanescens 2-5 maintained their activity when autoclaved at 120 degree centigrade for 20 min. The autoclaved filtrate of T. cyanescens 2-4 was more effective at inhibiting juvenile motility (CI50 = 28%) than that of T. cyanescens 2-5 (CI50 = 80%), C. robustum (CI50 = 72 %) and P. lilacinus (CI50 = 72%). The culture filtrate of T. cyanescens 2-4 also inhibited egg hatching. Nematode reproduction on Cleopatra mandarin and Carrizo citrange were respectively reduced by the culture filtrate of P. lilacinus and the autoclaved filtrate of T. cyanescens 2-4. These results support the hypothesis that soil fungi may contribute to regulate nematode densities by the production of secondary metabolites with nematicidal activity. (Author) 30 refs.

  10. Synthesis and formation of TlSr1212 superconductors from coprecipitated oxalate precursors

    Energy Technology Data Exchange (ETDEWEB)

    Salleh, F.Md. [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)]. E-mail: faizah163@salam.uitm.edu.my; Yahya, A.K. [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Imad, H. [Faculty of Science and Environmental Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Jumali, M.H. [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2005-10-01

    TlSr1212 superconductors were synthesized by solid-state reaction using Tl-containing precursor powder prepared by coprecipitation of metal acetates with stoichiometric ratio based on Tl{sub 0.8}Bi{sub 0.2}Sr{sub 2}Ca{sub 0.8}Y{sub 0.2}Cu{sub 2}O{sub 7{+-}}{sub {delta}} composition. The samples were sintered at temperatures between 870 and 980 deg. C for different durations. XRD patterns for samples sintered at 870 deg. C showed formation of dominant 1212 phase in addition to minor 1201 phase and SrCO{sub 3} impurity. At this sintering temperature, the best superconducting behavior with T {sub czero} of 94 K was observed for the sample sintered for 60 min. SEM investigations on the sample revealed elongated grains with a slight directional grain alignment. Effect of using metal acetates with a slightly different starting stoichiometric ratio of Tl{sub 0.96}Bi{sub 0.2}Sr{sub 1.6}Ca{sub 0.8}Y{sub 0.2}Cu{sub 2}O{sub 7{+-}}{sub {delta}} was also investigated.

  11. Room temperature ferromagnetism in Mn doped ZnO: Co nanoparticles by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Pazhanivelu, V.; Selvadurai, A. Paul Blessington [Department of Physics, Anna University, Chennai 600044 (India); Zhao, Yongsheng; Thiyagarajan, R. [Center for High Pressure Science and Technology Advanced Research, 1690 Cailun Road, Shanghai 201203 (China); Murugaraj, R., E-mail: r.murugaraj@gmail.com [Department of Physics, Anna University, Chennai 600044 (India)

    2016-01-15

    In this present work, the Mn{sup 2+} and Co{sup 2+} ions doping and co-doping effect on the structural, vibrational, morphological, optical and magnetic behaviors of ZnO based dilute magnetic semiconductors are reported. The Zn{sub 0.95}Co{sub 0.05}O (ZC), Zn{sub 0.95}Mn{sub 0.05}O (ZM) and Zn{sub 0.90}Co{sub 0.05}Mn{sub 0.05}O (ZCM) samples were prepared by co-precipitation method. From the XRD analysis, it was observed that on the doping of Mn{sup 2+} ion in ZnO matrix, decreases their crystalline nature as well as the crystallite size significantly. The Raman spectra, Photoluminescence and electron paramagnetic resonance spectroscopy measurements reveal that the presence of defects in prepared samples. The UV-DRS spectroscopic exhibits the incorporation of dopant ions and their effect on the band gap subsequently. The magnetization measurements suggest the room temperature ferromagnetism (RTFM) in the prepared samples. The observed RTFM phenomenon was discussed based on the defects and grain confinement.

  12. Structural Characterization of Spinel Zinc Aluminate Nanoparticles Prepared By Coprecipitation Method

    Science.gov (United States)

    Sunder, Shyam; Rohilla, Sunil; Kumar, Sushil; Aghamkar, Praveen

    2011-12-01

    Zinc aluminate is well known wide bandgap semiconductor with cubic spinel structure and transparent for wavelength greater than 320 nm. Therefore, ZnAl2O4 can be used for ultraviolet photoelectronic devices. Furthermore, spinel zinc aluminate is useful in many reactions as catalytic support. Moreover, zinc aluminate can be used as second phase in glaze layer of white ceramics to improve wear resistance and to preserve whiteness. In present study cubic spinel zinc aluminate nanoparticles have been synthesized from aqueous solution of Zn(NO3)2.6H2O (0.1 M) and Al(NO3)2.9H2O (0.2 M) using chemical coprecipitation technique. Ammonium hydroxide was used as precipitating agent and pH was maintained between 8 to 9. The precipitated slurry was filtered and washed several times with deionized double distilled water and dried at 110 °C. The fine powder was annealed at different temperatures from 600 °C to 900 °C for 4h in temperature controlled furnace. Structural characterization of annealed samples was carried out via X-ray Diffraction (XRD), and Fourier Transform Infrared spectroscopy (FTIR). XRD patterns reveal that zinc aluminate samples were cubic spinel nanoparticles and grain size determined by Debye-Scherrer formula is from 5 to 16 nm.

  13. Functionalization of emissive conjugated polymer nanoparticles by coprecipitation: consequences for particle photophysics and colloidal properties

    Science.gov (United States)

    Singh, Amita; Bezuidenhout, Michael; Walsh, Nichola; Beirne, Jason; Felletti, Riccardo; Wang, Suxiao; Fitzgerald, Kathleen T.; Gallagher, William M.; Kiely, Patrick; Redmond, Gareth

    2016-07-01

    The functionalization of polyfluorene (PFO) nanoparticles by coprecipitation of the conjugated polymer with an amphiphilic comb polymer, consisting of a hydrophobic polystyrene backbone with hydrophilic, carboxylic acid-terminated polyethylene oxide side-chains (PS-PEG-COOH), is investigated. The comb polymer affects the properties of the formed hybrid nanoparticles. Non-functionalized particles are typically larger (28 nm) than functionalized ones (20 nm); peak molar extinction coefficients are found to differ in a similar trend. Zeta potentials are negative, consistent with negative surface charge on PFO particles due to chemical defect formation, with additional charge on functionalized particles due to the pendant carboxylic acid groups. Emission quantum yields of functionalized particles are typically larger, consistent with lower efficiency of energy transfer to quenchers in smaller particles and weaker PFO interchain interactions due to chain dilution. The trend in per-particle fluorescence brightness values, as confirmed by single particle fluorescence imaging, reflects the nanoparticle extinction coefficients. Photostability studies on aqueous dispersions of hybrid particles indicate mild photobrightening under continuous illumination while PFO particles exhibit slow exponential emission decay. Functionalized particles are also resistant to aggregation during exposure to adenocarcinoma cells. Generally, the hybrid particles exhibit more favorable time-, pH- and medium-dependent stabilities, likely due to steric and electrostatic stabilization by PEG-carboxylic acid functionalities. Overall, the functionalized particles exhibit attractive properties: Reasonably small size, tight size distribution, high absorption cross section, radiative rate and emission quantum yield, excellent brightness and photostability, and good colloidal stability.

  14. Structural Characterization of Polymer-Clay Nanocomposites Prepared by Co-Precipitation Using EPR Techniques

    Directory of Open Access Journals (Sweden)

    Udo Kielmann

    2014-02-01

    Full Text Available Polymer-clay nanocomposites (PCNCs containing either a rubber or an acrylate polymer were prepared by drying or co-precipitating polymer latex and nanolayered clay (synthetic and natural suspensions. The interface between the polymer and the clay nanoparticles was studied by electron paramagnetic resonance (EPR techniques by selectively addressing spin probes either to the surfactant layer (labeled stearic acid or the clay surface (labeled catamine. Continuous-wave (CW EPR studies of the surfactant dynamics allow to define a transition temperature T* which was tentatively assigned to the order-disorder transition of the surfactant layer. CW EPR studies of PCNC showed that completely exfoliated nanoparticles coexist with agglomerates. HYSCORE spectroscopy in PCNCs showed couplings within the probe −assigned with DFT computations− and couplings with nuclei of the environment, 1H and 23Na for the surfactant layer probe, and 29Si, 7Li, 19F and 23Na for the clay surface probe. Analysis of these couplings indicates that the integrity of the surfactant layer is conserved and that there are sizeable ionic regions containing sodium ions directly beyond the surfactant layer. Simulations of the very weak couplings demonstrated that the HYSCORE spectra are sensitive to the composition of the clay and whether or not clay platelets stack.

  15. Synthesis of mono and multidomain YIG particles by chemical coprecipitation or ceramic procedure

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Garcia, L. [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Suarez, M., E-mail: m.suarez@cinn.e [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Menendez, J.L. [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo -UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)

    2010-04-09

    Yttrium iron garnet powders have been synthesized by chemical coprecipitation using two different precursors, nitrates and chlorides, and by an oxides mixture route. It is shown that depending on the precursors and synthesis conditions used pure yttrium iron garnet powders can be obtained with a mono or multidomain magnetic behaviour. The yttrium iron garnet crystalline structure, as studied by Raman spectroscopy, was already formed after calcination at temperatures as low as 800 {sup o}C when the nitrate precursors were used. However, calcination temperatures of up to 1100 {sup o}C were required to obtain yttrium iron garnet powders when the precursors were chlorides or when the oxides mixture route was chosen. The saturation magnetization of the powders correlates well with the structural characterization: when nitrate precursors were used, the saturation magnetization was already close to the bulk value, 26.8 emu/cm{sup 3}, after calcination at 800 {sup o}C. However, the saturation magnetization of the powders obtained by the chlorides and oxides mixture routes was close to zero up to calcination temperatures of 1100 {sup o}C. Finally, both the chlorides and the oxides mixture routes yield multidomain micron sized yttrium iron garnet powders, whereas the nitrates route led to monodomain submicron sized powders.

  16. Magnetic Properties of La/Ni-Substituted Strontium Hexaferrite Nanoparticles Prepared by Coprecipitation at Optimal Conditions

    Science.gov (United States)

    Ghanbari, F.; Arab, A.; Shishe Bor, M.; Mardaneh, M. R.

    2017-04-01

    La/Ni-substituted strontium hexaferrite Sr0.8La0.2Ni x Fe12- x O19 ( x = 0.2 to 1.0 in steps of 0.2) nanoparticles have been produced by a coprecipitation method at reaction and calcination temperature of 80°C and 1200°C, respectively. X-ray diffraction (XRD) analysis confirmed formation of single-phase M-type hexaferrite structure. The average crystallite size and morphology of the nanoparticles were obtained from XRD analysis and transmission electron microscopy (TEM), respectively. The magnetic properties in magnetic field of 12 kOe obtained from room-temperature hysteresis loops revealed minimum and maximum magnetization for x = 0.4 and 0.8, respectively, a behavior attributed to the ionic radii of the substituted cations, canted spin structure, electron hopping between cations, and the substitutional sites of the ions. It was also confirmed that the magnetization of nanoscale particles was lower than that of bulk material, which can be explained based on the different behavior of surface versus bulk atoms. The coercivity varied with x in a similar way to the magnetization, being related to sample anisotropy. In the M-type hexaferrite structure, substitution of Fe3+ by Ni2+ occurred at octahedral sites, making the greatest contribution to the anisotropy.

  17. Synthesis of strontium hexaferrite nanoparticles prepared using co-precipitation method and microemulsion processing

    Science.gov (United States)

    Drmota, A.; Žnidaršič, A.; Košak, A.

    2010-01-01

    Strontium hexaferrite (SrFe12O19) nanoparticles have been prepared with co-precipitation in aqueous solutions and precipitation in microemulsion system water/SDS/n-butanol/cyclohexane, using iron and strontium nitrates in different molar rations as a starting materials. The mixed Sr2+, Fe3+ hydroxide precursors obtained during the reaction between corresponding metal nitrates and tetramethylammonium hydroxide (TMAH), which served as a precipitating reagent, were calcined in a wide temperature range, from 350 °C to 1000 °C in a static air atmosphere. The influence of the Sr2+/Fe3+ molar ratio and the calcination temperature to the chemistry of the product formation, its crystallite size, morphology and magnetic properties were investigated. It was found that the formation of single phase SrFe12O19 with relatively high specific magnetization (54 Am2/kg) was achieved at the Sr2+/Fe3+ molar ration of 6.4 and calcination at 800 °C for 3h with heating/cooling rate 5 °C/min. The prepared powders were characterized using X-ray diffractometry (XRD) and specific surface area measurements (BET). The specific magnetization (DSM-10, magneto-susceptometer) of the prepared samples was measured.

  18. Synthesis and photocatalytic performances of BiVO 4 by ammonia co-precipitation process

    Science.gov (United States)

    Yu, Jianqiang; Zhang, Yan; Kudo, Akihiko

    2009-02-01

    This paper reports the preparation and photocatalytic performance of Bismuth vanadate (BiVO 4) by a facile and inexpensive approach. An amorphous BiVO 4 was first prepared by a co-precipitation process from aqueous solutions of Bi(NO 3) 3 and NH 4VO 3 using ammonia. Followed by heating treatment at various temperatures, the amorphous phase converted to crystalline BiVO 4 with a structure between monoclinic and tetragonal scheelite. The crystallization of BiVO 4 occurred at about 523 K, while the nanocrystalline BiVO 4 were formed with a heat-treatment of lower than 673 K. However, when the heat-treatment was carried out at 773 K, the accumulation of nanocrystals to bulk particles was observed. The photocatalytic performances of the materials were investigated by O 2 evolution under visible-light, and MB decomposition under solar simulator. The results demonstrated that the crystalline structure is still the vital factor for the activities of both reactions. However, the crystallinity of BiVO 4 gives a major influence on the activity of O 2 evolution, whereas the surface area, plays an important role for photocatalytic MB decomposition.

  19. Uranium Redox Transformations after U(VI) Coprecipitation with Magnetite Nanoparticles.

    Science.gov (United States)

    Pidchenko, Ivan; Kvashnina, Kristina O; Yokosawa, Tadahiro; Finck, Nicolas; Bahl, Sebastian; Schild, Dieter; Polly, Robert; Bohnert, Elke; Rossberg, André; Göttlicher, Jörg; Dardenne, Kathy; Rothe, Jörg; Schäfer, Thorsten; Geckeis, Horst; Vitova, Tonya

    2017-02-21

    Uranium redox states and speciation in magnetite nanoparticles coprecipitated with U(VI) for uranium loadings varying from 1000 to 10 000 ppm are investigated by X-ray absorption spectroscopy (XAS). It is demonstrated that the U M4 high energy resolution X-ray absorption near edge structure (HR-XANES) method is capable to clearly characterize U(IV), U(V), and U(VI) existing simultaneously in the same sample. The contributions of the three different uranium redox states are quantified with the iterative transformation factor analysis (ITFA) method. U L3 XAS and transmission electron microscopy (TEM) reveal that initially sorbed U(VI) species recrystallize to nonstoichiometric UO2+x nanoparticles within 147 days when stored under anoxic conditions. These U(IV) species oxidize again when exposed to air. U M4 HR-XANES data demonstrate strong contribution of U(V) at day 10 and that U(V) remains stable over 142 days under ambient conditions as shown for magnetite nanoparticles containing 1000 ppm U. U L3 XAS indicates that this U(V) species is protected from oxidation likely incorporated into octahedral magnetite sites. XAS results are supported by density functional theory (DFT) calculations. Further characterization of the samples include powder X-ray diffraction (pXRD), scanning electron microscopy (SEM) and Fe 2p X-ray photoelectron spectroscopy (XPS).

  20. Heating ability and hemolysis test of magnetite nanoparticles obtained by a simple co-precipitation method

    Directory of Open Access Journals (Sweden)

    B.I. Macías-Martínez

    2016-08-01

    Full Text Available The present paper reports the heating ability and hemolysis test of magnetite nanoparticles (MNPs for biomedical applications, obtained by a novel and easy co-precipitation method, in which it is not necessary the use of controlled atmospheres and high stirring rates. Different molar proportions of FeCl2:FeCl3 (2:1 and 3:2 respectively were used and the obtained MNPs were analyzed by X-ray diffraction, vibrating sample magnetometry and transmission electron microscopy. The heating ability was evaluated under a magnetic field using a solid state induction heating equipment at two different frequencies (362 and 200 kHz. Additionally, a hemolysis test was performed according to the ASTM method. The obtained ferrites showed a particle size in the range of 8–12 nm and superparamagnetic behavior. The MNPs increased the temperature up to 43.1 °C in 5 min under a low magnetic field and showed non hemolytic effect up to 3 mg/ml. The MNPs obtained are highly potential materials for hyperthermia cancer treatment.

  1. Structural and magnetic properties of calcium doped nickel ferrite nanoparticles by co-precipitation method

    Science.gov (United States)

    Vigneswari, T.; Raji, P.

    2017-01-01

    It is a truism that a sequence of calcium doped nickel ferrite (with x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanoparticles are combined by co-precipitation technique. X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) scrutinize the formation of single-phase inverse spinel structure in all the compositions. The lattice framework increases with the increase in calcium concentration and it exhibits the development of unit cell. Crystallite size in the range of 22-34 nm is viewed and also augmented the level of calcium. The elemental composition of pure and calcium doped nickel ferrite has been procured from Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Energy Dispersive X-ray analysis (EDX). It is interesting to note that the substitution of calcium increasingly exerts influence on the magnetic characteristics. These observations paved the way for the room temperature of magnetization measurements. The saturation magnetization and the experimental value of magnetic moment are noticed to enlarge initially up to x = 0.2, and then decrease incessantly with increase in the Ca content x. The increase and the decrease of saturation magnetization have widely been expounded by Neel's collinear two-sublattice model and Yafet-Kittel (Y-K) three-sub lattice model.

  2. Cerium and neodymium co-precipitation in molten chloride by wet argon sparging

    Energy Technology Data Exchange (ETDEWEB)

    Vigier, J.F. [CEA, Nuclear Energy Division, RadioChemistry and Processes Department, SMCS/LEPS, F-30207 Bagnols sur Ceze (France); Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, Univ. Lille Nord de France, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d' Ascq Cedex (France); Renard, C., E-mail: catherine.renard@ensc-lille.fr [Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, Univ. Lille Nord de France, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d' Ascq Cedex (France); Laplace, A. [CEA, Nuclear Energy Division, RadioChemistry and Processes Department, SMCS/LEPS, F-30207 Bagnols sur Ceze (France); Lacquement, J. [CEA, Nuclear Energy Division, DTEC/DIR, F-30207 Bagnols sur Ceze (France); Abraham, F. [Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, Univ. Lille Nord de France, ENSCL-USTL, B.P. 90108, 59652 Villeneuve d' Ascq Cedex (France)

    2013-01-15

    Co-precipitations of cerium (III) and neodymium (III) at 10 wt.% in LiCl-CaCl{sub 2} (30-70 mol%) molten salt at 705 Degree-Sign C have been achieved using an original way of precipitation, wet argon sparging. Several CeCl{sub 3}/NdCl{sub 3} ratios have been studied, and the isolated powders were analyzed using different characterization methods including XRD investigations. The lanthanides precipitation yields have been determined around 99.9% using ICP-AES analysis. XRD demonstrated that the precipitates mainly contained mixed oxychloride (Ce{sub 1-x}Nd{sub x})OCl and a small amount of the mixed oxide Ce{sub 1-y}Nd{sub y}O{sub 2-0.5y}. Calcination of these precipitates has resulted in the cerium and neodymium mixed oxides. For the precipitation with a Ce/Nd = 50/50 ratio, an hydroxychloride Ln(OH){sub 2}Cl and the oxychloride Ce{sup IV}(Nd{sub 0.7}Ce{sub 0.3}){sup III}O{sub 3}Cl have been identified as unexpected intermediate compounds.

  3. Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method.

    Science.gov (United States)

    Kalantari, Katayoon; Bin Ahmad, Mansor; Shameli, Kamyar; Khandanlou, Roshanak

    2013-01-01

    The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe(3)O(4)) nanoparticles on talc layers using an environmentally friendly process. The Fe(3)O(4) magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe(3)O(4) precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94-0.93 nm); therefore, Fe(3)O(4) nanoparticles formed on the exterior surface of talc, with an average size of 1.95-2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe(3)O(4) nanocomposites may have potential applications in the chemical and biological industries.

  4. Co-Precipitation Synthesis of Gadolinium Aluminum Gallium Oxide (GAGG) via Different Precipitants

    Science.gov (United States)

    Sun, Yan; Yang, Shenghui; Zhang, Ye; Jiang, Jun; Jiang, Haochuan

    2014-02-01

    In order to obtain a uniform transparent ceramic scintillator, well-dispersed fine starting powders with high-purity, small grain size, spherical morphology and high sinter-ability are necessary. In this study, Ce3+ doped gadolinium aluminum gallium garnet Gd3Al3Ga2O12 (GAGG) powders were synthesized by the co-precipitation method. NH4OH, NH4HCO3 and the mixed solution of NH4OH and NH4HCO3 were used as precipitants, respectively. The precursor composition, phase formation process, microstructure, morphology, particle size distribution and luminescent properties of obtained GAGG powders were measured. The results show that powders prepared using the mixed precipitant exhibit the best microstructural morphology, good sinter-ability and highest luminescent intensity. Pure GAGG polycrystalline powders could be obtained at about 950°C for 1.5 h and the average size of the particles is about 50 nm. The photoluminescence spectrum shows a strong green-yellow emission near 540 nm.

  5. Effect of Calcination Conditions on the Performance of Co-precipitation Catalyst

    Directory of Open Access Journals (Sweden)

    Lin Kai

    2016-01-01

    Full Text Available The Fe-Co-Ce composite catalysts were prepared by co-precipitation method, and the effect of calcination temperature and calcination time on the performances of the Fe-Co-Ce composite catalysts were investigated. The results indicated that the optimum calcination temperature and calcination time of the Fe-Co-Ce composite catalysts were 450 °C and 7 h, respectively. Using the catalysts which prepared under the optimum calcination conditions catalytic wet oxidation of methyl orange simulated wastewater, after 90 min, the COD, COD removal rate, absorbance, decolorization rate and pH of the methyl orange simulated wastewater were 737.7, 70.5%, 0.348, 95.3%, and 5.31, respectively. According to the analyses of the SEM, FTIR, and TG-DTA curves, the components of the catalysts which prepared under the optimum calcination conditions distributed evenly, and the chemical compositions of the catalysts including C-O, -OH, and H-O-H, showing a good thermal stability.

  6. Methane Decomposition into Carbon Fibers over Coprecipitated Nickel-Based Catalysts

    Institute of Scientific and Technical Information of China (English)

    Yan Ju; Fengyi Li; Renzhong Wei

    2005-01-01

    Decomposition of methane in the presence of coprecipitated nickel-based catalysts to produce carbon fibers was investigated. The reaction was studied in the temperature range of 773 K to 1073 K.At 1023 K, the catalytic activities of three catalysts kept high at the initial period and then decreased with the reaction time. The lifetimes of Ni-Cu-Al and Ni-La-Al catalysts are longer than that of Ni-Al catalyst. With three catalysts, the yield of carbon fibers was very low at 773 K. The yield of carbon fibers for Ni-La-Al catalyst was more than those for Ni-Al and Ni-Cu-Al catalysts. For Ni-La-Al catalyst, the elevation of temperature from 873 K up to 1073 K led gradually to an increase in the yield of carbon fibers.XRD studies on the Ni-La-Al catalyst indicate that La2NiO4 was formed. The formation of La2NiO4 is responsible for the increase in the catalytic lifetime and the yield of carbon fibers synthesized on Ni-La-Al at 773-1073 K. Carbon fibers synthesized on Ni-Al catalyst are thin, long carbon nanotubes. There are bamboo-shaped carbon fibers synthesized on Ni-Cu-Al catalyst. Carbon fibers synthesized on Ni-La-Al catalyst have large hollow core, thin wall and good graphitization.

  7. Tunable Band Gap Energy of Mn-Doped ZnO Nanoparticles Using the Coprecipitation Technique

    Directory of Open Access Journals (Sweden)

    Tong Ling Tan

    2014-01-01

    Full Text Available A simple coprecipitation technique was introduced to form manganese (Mn doped on zinc oxide (ZnO nanoparticles effectively. Based on our morphological studies, it was revealed that mean particle size was increased while bigger agglomeration of nanoparticles could be observed as the amount of concentration of Mn was increased. Interestingly, it was found that the position of the absorption spectra was shifted towards the lower wavelength (UV region as correlated with the increasing of Mn dopants concentration into ZnO nanoparticles. This result inferred that optimum content of Mn doped into the ZnO nanoparticles was crucial in controlling the visible/UV-responsive of samples. In the present study, 3 mol% of Mn dopants into the ZnO nanoparticles exhibited the better UV as well as visible light-responsive as compared to the other samples. The main reason might be attributed to the modification of electronic structure of ZnO nanoparticles via lattice doping of Mn ions into the lattice, whereas excessive Mn dopants doped on ZnO nanoparticles caused the strong UV-responsive due to the more 3d orbitals in the valence band.

  8. Co-precipitation synthesis of lutetium aluminum garnet (LuAG) powders: The influence of ethanol

    Science.gov (United States)

    Pan, Liangjie; Jiang, Benxue; Fan, Jintai; Zhang, Pande; Mao, Xiaojian; Zhang, Long

    2017-09-01

    Aluminum Garnet (LuAG) precursors were co-precipitated by using ethanol-water as the precipitant solvent. The effect of different volume ratios of ethanol to water (R) on the preparation of pure-phase LuAG powders has been mainly studied. The evolution of phase, composition and micro-structure of the as-synthesized LuAG powders were characterized by TG/DTA, FTIR, XRD, BET, and SEM. The BET-equivalent diameter of LuAG nano particles increased with R. The ethanol-water solvent does not change the main composition of the LuAG precursors, but has great influence on the morphology of the final LuAG nano particles. Uniformly dispersed LuAG powders calcined at 1200 °C for 3 h with a particle size of approximately 120 nm were obtained by using ethanol-water solvent with proper R = 1. The mechanism of ethanol in the preparation process was discussed.

  9. Effects of Heating Processing on Microstructure and Magnetic Properties of Mn-Zn Ferrites Prepared via Chemical Co-precipitation

    Institute of Scientific and Technical Information of China (English)

    CHEN Shijie; XIA Jingbing; DAI Jianqing

    2015-01-01

    The fine powders of Mn-Zn ferrites with uniform size were prepared via chemical co-precipitation method. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), frequency dependence of permeability and metallographical microscope were used to investigate the crystal structure, surface topography and magnetic properties of the powders and the sintering samples. The experimental results demonstrate that the precursor powders have formed a pure phase cubic spinel MnxZn1-xFe2O4 while in the reactor and show deifnite magnetism, which can solve the dififcult issue in washing process effectively. When calcined beneath 450℃, the powders have intact crystal form and the crystallite size is less than 20 nm. Comparison tests of sintering temperatures show that 1 300℃ is the ideal sintering temperature for Mn-Zn ferrites prepared by using the chemical co-precipitation.

  10. CoFe2O4@MIL-100(Fe) hybrid magnetic nanoparticles exhibit fast and selective adsorption of arsenic with high adsorption capacity

    Science.gov (United States)

    Yang, Ji-Chun; Yin, Xue-Bo

    2017-01-01

    In this study, we report the synthesis and application of mesoporous CoFe2O4@MIL-100(Fe) hybrid magnetic nanoparticles (MNPs) for the simultaneous removal of inorganic arsenic (iAs). The hybrid adsorbent had a core-shell and mesoporous structure with an average diameter of 260 nm. The nanoscale size and mesoporous character impart a fast adsorption rate and high adsorption capacity for iAs. In total, 0.1 mg L−1 As(V) and As(III) could be adsorbed within 2 min, and the maximum adsorption capacities were 114.8 mg g−1 for As(V) and 143.6 mg g−1 for As(III), higher than most previously reported adsorbents. The anti-interference capacity for iAs adsorption was improved by the electrostatic repulsion and size exclusion effects of the MIL-100(Fe) shell, which also decreased the zero-charge point of the hybrid absorbent for a broad pH adsorption range. The adsorption mechanisms of iAs on the MNPs are proposed. An Fe-O-As structure was formed on CoFe2O4@MIL-100(Fe) through hydroxyl substitution with the deprotonated iAs species. Monolayer adsorption of As(V) was observed, while hydrogen bonding led to the multi-layer adsorption of neutral As(III) for its high adsorption capacity. The high efficiency and the excellent pH- and interference-tolerance capacities of CoFe2O4@MIL-100(Fe) allowed effective iAs removal from natural water samples, as validated with batch magnetic separation mode and a portable filtration strategy. PMID:28102334

  11. CoFe2O4@MIL-100(Fe) hybrid magnetic nanoparticles exhibit fast and selective adsorption of arsenic with high adsorption capacity

    Science.gov (United States)

    Yang, Ji-Chun; Yin, Xue-Bo

    2017-01-01

    In this study, we report the synthesis and application of mesoporous CoFe2O4@MIL-100(Fe) hybrid magnetic nanoparticles (MNPs) for the simultaneous removal of inorganic arsenic (iAs). The hybrid adsorbent had a core-shell and mesoporous structure with an average diameter of 260 nm. The nanoscale size and mesoporous character impart a fast adsorption rate and high adsorption capacity for iAs. In total, 0.1 mg L‑1 As(V) and As(III) could be adsorbed within 2 min, and the maximum adsorption capacities were 114.8 mg g‑1 for As(V) and 143.6 mg g‑1 for As(III), higher than most previously reported adsorbents. The anti-interference capacity for iAs adsorption was improved by the electrostatic repulsion and size exclusion effects of the MIL-100(Fe) shell, which also decreased the zero-charge point of the hybrid absorbent for a broad pH adsorption range. The adsorption mechanisms of iAs on the MNPs are proposed. An Fe-O-As structure was formed on CoFe2O4@MIL-100(Fe) through hydroxyl substitution with the deprotonated iAs species. Monolayer adsorption of As(V) was observed, while hydrogen bonding led to the multi-layer adsorption of neutral As(III) for its high adsorption capacity. The high efficiency and the excellent pH- and interference-tolerance capacities of CoFe2O4@MIL-100(Fe) allowed effective iAs removal from natural water samples, as validated with batch magnetic separation mode and a portable filtration strategy.

  12. Competitive and Cooperative Effects during Nickel Adsorption to Iron Oxides in the Presence of Oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Elaine D. [Department of Earth and Planetary; Catalano, Jeffrey G. [Department of Earth and Planetary

    2017-08-09

    Iron oxides are ubiquitous in soils and sediments and play a critical role in the geochemical distribution of trace elements and heavy metals via adsorption and coprecipitation. The presence of organic acids may potentially alter how metals associate with iron oxide minerals through a series of cooperative or competitive processes: solution complexation, ternary surface complexation, and surface site competition. The macroscopic and molecular-scale effects of these processes were investigated for Ni adsorption to hematite and goethite at pH 7 in the presence of oxalate. The addition of this organic acid suppresses Ni uptake on both minerals. Aqueous speciation suggests that this is dominantly the result of oxalate complexing and solubilizing Ni. Comparison of the Ni surface coverage to the concentration of free (uncomplexed) Ni2+ in solution suggests that the oxalate also alters Ni adsorption affinity. EXAFS and ATR-FTIR spectroscopies indicate that these changes in binding affinity are due to the formation of Ni–oxalate ternary surface complexes. These observations demonstrate that competition between dissolved oxalate and the mineral surface for Ni overwhelms the enhancement in adsorption associated with ternary complexation. Oxalate thus largely enhances Ni mobility, thereby increasing micronutrient bioavailability and inhibiting contaminant sequestration.

  13. Structural characterization and adsorption properties of pluronic F127 onto iron oxides magnetic nanoparticles.

    Science.gov (United States)

    Dehvari, Khalilalrahman; Lin, Kuen-Song; Wang, Steven S S

    2014-03-01

    Superparamagnetic iron oxide nanoparticles coated with polymers have shown low toxicity and chemical stability in physiological condition, thereby can be used to deliver encapsulated drugs throughout the body by external magnetic fields. In this study, magnetic nanoparticles were synthesized thorough co-precipitation method and their interaction with Pluronic F127 block copolymer as well as adsorption properties of polymer onto nanoparticles were investigated. Adsorption measurement revealed different adsorption behaviors below and above the polymer's critical micelle concentration. The Freundlich isotherm was found to better describe the adsorption behavior of Pluronic F127 onto SIONPs particles below the block copolymer critical micelle concentration. At higher concentration, the adsorbed amount is likely to diminish due to interpenetration of the adsorbed macromolecular micelles and volume-excluded effects for block copolymers. Furthermore, magnetic nanocomposites with different concentration of polymers were prepared through hydrothermal method. The crystalline structure, morphology, pore structure, and magnetic properties of magnetic nanoparticles/nanocomposites products at different pH and polymer concentration were studied. Results showed that due to the hematite impurities, magnetic nanocomposites synthesized at higher pH have lower magnetization.

  14. SrAl2O4 :Eu2+, Dy3+ Long Afterglow Phosphors Prepared by Chemical Coprecipitation Method

    Institute of Scientific and Technical Information of China (English)

    Sun Yanbin; Qiu Guanming; Zhang Shengqu; Zhang Ming; Yan Changhao; Dai Shaojun

    2004-01-01

    SrAl2 O4: Eu2+ , Dy3+ long afterglow phosphors were prepared by chemical coprecipitation method. Ammonium carbonate and ammonium hydrogen carbonate were used as the precipitants. The preparation of the SrAl2 O4: Eu2+ ,Dy3 + precursor was completed at room temperature by controlling the concentration of the metal-salt solution, pH value of the system, etc. The phosphors were prepared by sintering the precursor at 1000 ~ 1200 ℃ in a weak reducing atmosphere for 2 h. The XRD, SEM, excitation spectra, emission spectra and afterglow decay of the samples were tested and the optimal synthesis conditions of the SrAl2O4: Eu2+ , Dy3+ long afterglow phosphors prepared by precipitation method were determined. The phosphor which had good luminescent properties is prepared and its persistent time can reach more than 1600 min. In the coprecipitation process, a small amount of glucose operates to refe the luminescent powders. The particle size of the phosphor can be less than 1 μm. The sintering temperature of the sample prepared by the coprecipitation method is much lower than that of the one prepared by the high temperature solid state method.Compared with the high temperature solid state method, a clear blue shift occurs in the excitation and emission spectra of the samples.

  15. Mercury (II) reduction and co-precipitation of metallic mercury on hydrous ferric oxide in contaminated groundwater.

    Science.gov (United States)

    Richard, Jan-Helge; Bischoff, Cornelia; Ahrens, Christian G M; Biester, Harald

    2016-01-01

    Mercury (Hg) speciation and sorption analyses in contaminated aquifers are useful for understanding transformation, retention, and mobility of Hg in groundwater. In most aquifers hydrous ferric oxides (HFOs) are among the most important sorbents for trace metals; however, their role in sorption or mobilization of Hg in aquifers has been rarely analyzed. In this study, we investigated Hg chemistry and Hg sorption to HFO under changing redox conditions in a highly HgCl2-contaminated aquifer (up to 870μgL(-1) Hg). Results from aqueous and solid phase Hg measurements were compared to modeled (PHREEQC) data. Speciation analyses of dissolved mercury indicated that Hg(II) forms were reduced to Hg(0) under anoxic conditions, and adsorbed to or co-precipitated with HFO. Solid phase Hg thermo-desorption measurements revealed that between 55 and 93% of Hg bound to HFO was elemental Hg (Hg(0)). Hg concentrations in precipitates reached more than 4 weight %, up to 7000 times higher than predicted by geochemical models that do not consider unspecific sorption to and co-precipitation of elemental Hg with HFO. The observed process of Hg(II) reduction and Hg(0) formation, and its retention and co-precipitation by HFO is thought to be crucial in HgCl2-contaminated aquifers with variable redox-conditions regarding the related decrease in Hg solubility (factor of ~10(6)), and retention of Hg in the aquifer.

  16. Sorghum genome sequencing by methylation filtration.

    Directory of Open Access Journals (Sweden)

    Joseph A Bedell

    2005-01-01

    Full Text Available Sorghum bicolor is a close relative of maize and is a staple crop in Africa and much of the developing world because of its superior tolerance of arid growth conditions. We have generated sequence from the hypomethylated portion of the sorghum genome by applying methylation filtration (MF technology. The evidence suggests that 96% of the genes have been sequence tagged, with an average coverage of 65% across their length. Remarkably, this level of gene discovery was accomplished after generating a raw coverage of less than 300 megabases of the 735-megabase genome. MF preferentially captures exons and introns, promoters, microRNAs, and simple sequence repeats, and minimizes interspersed repeats, thus providing a robust view of the functional parts of the genome. The sorghum MF sequence set is beneficial to research on sorghum and is also a powerful resource for comparative genomics among the grasses and across the entire plant kingdom. Thousands of hypothetical gene predictions in rice and Arabidopsis are supported by the sorghum dataset, and genomic similarities highlight evolutionarily conserved regions that will lead to a better understanding of rice and Arabidopsis.

  17. Capturing phosphates with iron enhanced sand filtration.

    Science.gov (United States)

    Erickson, Andrew J; Gulliver, John S; Weiss, Peter T

    2012-06-01

    Most treatment practices for urban runoff capture pollutants such as phosphorus by either settling or filtration while dissolved phosphorus, typically as phosphates, is untreated. Dissolved phosphorus, however, represents an average 45% of total phosphorus in stormwater runoff and can be more than 95%. In this study, a new stormwater treatment technology to capture phosphate, called the Minnesota Filter, is introduced. The filter comprises iron filings mixed with sand and is tested for phosphate removal from synthetic stormwater. Results indicate that sand mixed with 5% iron filings captures an average of 88% phosphate for at least 200 m of treated depth, which is significantly greater than a sand filter without iron filings. Neither incorporation of iron filings into a sand filter nor capture of phosphates onto iron filings in column experiments had a significant effect on the hydraulic conductivity of the filter at mixtures of 5% or less iron by weight. Field applications with up to 10.7% iron were operated over 1 year without detrimental effects upon hydraulic conductivity. A model is applied and fit to column studies to predict the field performance of iron-enhanced sand filters. The model predictions are verified through the predicted performance of the filters in removing phosphates in field applications. Practical applications of the technology, both existing and proposed, are presented so stormwater managers can begin implementation.

  18. Crosslinked polytriazole membranes for organophilic filtration

    KAUST Repository

    Chisca, Stefan

    2016-12-30

    We report the preparation of crosslinked membranes for organophilic filtration, by reacting a new polytriazole with free OH groups, using non-toxic poly (ethylene glycol) diglycidyl ether (PEGDE). The OH-functionalized polymer was obtained by converting the oxadiazole to triazole rings with high yield (98%). The maximum degree of crosslinking is achieved after 6 h of reaction. The crosslinked polytriazole membranes are stable in a wide range of organic solvents and show high creep recovery, indicating the robustness of crosslinked membranes. The influence of different casting solutions and different crosslinking time on the membrane morphology and membrane performance was investigated. The membranes performance was studied in dimethylformamide (DMF) and (tetrahydrofuran) THF. We achieved a permeance for THF of 49 L m−2 h−1 bar−1 for membranes with molecular weight cut off (MWCO) of 7 kg mol−1 and a permeance for THF of 17.5 L m−2 h−1 bar−1 for membranes with MWCO of 3 kg mol−1. Our data indicate that by using the new polytriazole is possible to adjust the pore dimensions of the membranes to have a MWCO, which covers ultra- and nanofiltration range.

  19. Estimating Glomerular Filtration Rate in Older People

    Directory of Open Access Journals (Sweden)

    Sabrina Garasto

    2014-01-01

    Full Text Available We aimed at reviewing age-related changes in kidney structure and function, methods for estimating kidney function, and impact of reduced kidney function on geriatric outcomes, as well as the reliability and applicability of equations for estimating glomerular filtration rate (eGFR in older patients. CKD is associated with different comorbidities and adverse outcomes such as disability and premature death in older populations. Creatinine clearance and other methods for estimating kidney function are not easy to apply in older subjects. Thus, an accurate and reliable method for calculating eGFR would be highly desirable for early detection and management of CKD in this vulnerable population. Equations based on serum creatinine, age, race, and gender have been widely used. However, these equations have their own limitations, and no equation seems better than the other ones in older people. New equations specifically developed for use in older populations, especially those based on serum cystatin C, hold promises. However, further studies are needed to definitely accept them as the reference method to estimate kidney function in older patients in the clinical setting.

  20. Pulmonary interstitial compliance and microvascular filtration coefficient.

    Science.gov (United States)

    Goldberg, H S

    1980-08-01

    Static and dynamic properties governing the fluid movement into the pulmonary interstitium were examined in isolated canine lobes. The system was driven by altering intravascular presure (Piv) when the lobe was isogravimetric (change in weight (W) = 0) and allowing the lobe to become isogravimetric again. By making use of an analogy to charging a capacitor across a resistor, calculation of the filtration coefficient for transvascular fluid movement (KF) and determination of the pressure-volume relationship of the pulmonary interstitial space (Pis-Vis), with a minimum of untested assumptions, was possible. KF was found to be the same for fluid moving out of or into the intravascular space, and when the relationship between Piv and alveolar pressure (PAlv) was constant, KF was independent of transpulmonary pressure (PL). When PAlv exceeded Piv, changes in Piv did not influence KF, suggesting no significant change in either surface area available for fluid transudation or vascular permeability. The Pis-Vis curve for increasing values of Vis and Pis is best described by an exponential relationhip and is independent of PL. However, the Pis-Vis curve with decreasing values of Vis and Pis is dependent on PL.

  1. Sorghum genome sequencing by methylation filtration.

    Science.gov (United States)

    Bedell, Joseph A; Budiman, Muhammad A; Nunberg, Andrew; Citek, Robert W; Robbins, Dan; Jones, Joshua; Flick, Elizabeth; Rholfing, Theresa; Fries, Jason; Bradford, Kourtney; McMenamy, Jennifer; Smith, Michael; Holeman, Heather; Roe, Bruce A; Wiley, Graham; Korf, Ian F; Rabinowicz, Pablo D; Lakey, Nathan; McCombie, W Richard; Jeddeloh, Jeffrey A; Martienssen, Robert A

    2005-01-01

    Sorghum bicolor is a close relative of maize and is a staple crop in Africa and much of the developing world because of its superior tolerance of arid growth conditions. We have generated sequence from the hypomethylated portion of the sorghum genome by applying methylation filtration (MF) technology. The evidence suggests that 96% of the genes have been sequence tagged, with an average coverage of 65% across their length. Remarkably, this level of gene discovery was accomplished after generating a raw coverage of less than 300 megabases of the 735-megabase genome. MF preferentially captures exons and introns, promoters, microRNAs, and simple sequence repeats, and minimizes interspersed repeats, thus providing a robust view of the functional parts of the genome. The sorghum MF sequence set is beneficial to research on sorghum and is also a powerful resource for comparative genomics among the grasses and across the entire plant kingdom. Thousands of hypothetical gene predictions in rice and Arabidopsis are supported by the sorghum dataset, and genomic similarities highlight evolutionarily conserved regions that will lead to a better understanding of rice and Arabidopsis.

  2. Filtration application from recycled expanded polystyrene.

    Science.gov (United States)

    Shin, C

    2006-10-01

    Water-in-oil emulsion with drop size less than 100 mum is difficult to separate. Coalescence filtration is economical and effective for separation of secondary dispersions. Coalescence performance depends on flow rate, bed depth, fiber surface properties, and drop size. The amount of surface area of the fibers directly affects the efficiency. A new recycling method was investigated in the previous work in which polystyrene (PS) sub-mum fibers were electro-spun from recycled expanded polystyrene (EPS). These fibers are mixed with micro glass fibers to modify the glass fiber filter media. The filter media are tested in the separation of water droplets from an emulsion of water droplets in oil. The experimental results in this work show that adding nanofibers to conventional micron sized fibrous filter media improves the separation efficiency of the filter media but also increases the pressure drop. An optimum in the performance occurs (significant increase in efficiency with minimal increase in pressure drop) with the addition of about 4% by mass of 500 nm diameter PS nanofibers to glass fibers for the filters.

  3. Efficient filtration system for paraffin-catalyst slurry separation

    Directory of Open Access Journals (Sweden)

    Khodagholi Mohammad Ali

    2013-01-01

    Full Text Available The filtration efficiency for separating liquid paraffin (or water from a slurry consisting of 25 weight% spherical alumina in a Slurry Bubble Column Reactor (SBCR comprised of a cylindrical tube of 10 cm diameter and 150 cm length was studied. Various differential pressures (ΔP were applied to two separate tubular sintered metal stainless steel filter elements with nominal pore size of 4 and 16μm. The experimental results disclosed that the rate of filtrations increased on applying higher differential pressure to the filter element. Albeit this phenomenon is limited to moderate ΔPs and for ΔP more than 1 bar is neither harmful nor helpful. The highest filtration rates at ΔPs higher than 1 bar were 170 and 248 ml/minute for 4 and 16μm respectively. Using water as the liquid in slurry the rate of filtration enhanced to 4 folds, and this issue reveals impact of viscosity on filtration efficiency clearly. In all situations, the total amount of particles present in the filtrate part never exceeded a few parts per million (ppm. The statistical analysis of the SEM image of the filtrate indicated that by applying higher pressure difference to the filter element the frequency percent of larger particle size increases. The operation of filter cake removing was performed with back flashing of 300 ml of clean liquid with pressures of 3-5 bar of N2 gas.

  4. Carbonaceous materials for adsorptive refrigerators

    Science.gov (United States)

    Buczek, B.; Wolak, E.

    2012-06-01

    Carbon monoliths prepared from hard coal precursors were obtained. The porous structure of the monoliths was evaluated on the basis of nitrogen adsorption — desorption equilibrium data. The investigated monoliths have a well-developed microporous structure with significant specific surface area (S BET ). Equilibrium studies of methanol vapour adsorption were used to characterize the methanol adsorptive capacity that was determined using a volumetric method. The heat of wetting by methanol was determined in order to estimate the energetic effects of the adsorption process. The results of the investigations show that all monoliths exhibit high adsorption capacity and high heat of wetting with methanol.

  5. Adsorption removal of Sr by Barium impregnated 4A Zeolite(BaA) from high radioactive seawater waste

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eil Hee; Lee, Keun Young; Kim, Kwang Wook; Kim, Ik Soo; Chung, Dong Yong; Moon, Jei Kwon; Choi, Jong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-06-15

    This study investigated the removal of Sr, which was one of the high radioactive nuclides, by adsorption with Barium (Ba) impregnated 4A zeolite (BaA) from high-radioactive seawater waste (HSW). Adsorption of Sr by BaA (BaA-Sr), in the impregnated Ba concentration of above 20.2wt%, was decreased by increasing the impregnated Ba concentration, and the impregnated Ba concentration was suitable at 20.2wt%. The BaA-Sr adsorption was added to the co-precipitation of Sr with BaSO4 precipitation in the adsorption of Sr by 4A (4A-Sr) within BaA. Thus, it was possible to remove Sr more than 99% at m/V (adsorbent weight/solution volume)=5 g/L for BaA and m/V >20 g/L for 4A, respectively, in the Sr concentration of less than 0.2 mg/L (actual concentration level of Sr in HSW). It shows that BaA-Sr adsorption is better than 4A-Sr adsorption in for the removal capacity of Sr per unit gram of adsorbent, and the reduction of the secondary solid waste generation (spent adsorbent etc.). Also, BaA-Sr adsorption was more excellent removal capacity of Sr in the seawater waste than distilled water. Therefore, it seems to be effective for the direct removal of Sr from HSW. On the other hand, the adsorption of Cs by BaA (BaA-Cs) was mainly performed by 4A within BaA. Accordingly, it seems to be little effect of impregnated Ba into BaA. Meanwhile, BaA-Sr adsorption kinetics could be expressed the pseudosecond order rate equation. By increasing the initial Sr concentrations and the ratios of V/m, the adsorption rate constants (k2) were decreased, but the equilibrium adsorption capacities (qe) were increasing. However, with increasing the temperature of solution, k2 was conversely increased, and qe was decreased. The activation energy of BaA-Sr adsorption was 38 kJ/mol. Thus, the chemical adsorption seems to be dominant rather than physical adsorption, although it is not a chemisorption with strong bonding form.

  6. Forward osmosis filtration for removal of organic foulants: Effects of combined tannic and alginic acids.

    Science.gov (United States)

    Wang, Lin; Zhang, Wanzhu; Chu, Huaqiang; Dong, Bingzhi

    2016-03-15

    The filtration performance of combined organic foulants by forward osmosis (FO) in active-layer-facing-the-draw-solution (AL-facing-DS) orientation was investigated systematically. Tannic acid and alginate were used as model organic foulants for polysaccharides and humic dissolved organic matters, respectively. The FO could reject combined and single tannic acid and alginate foulants effectively. The more severe fouling flux decline, accompanied with lower combined foulants' retention, was observed with increasing proportions of tannic acid in the combined foulants-containing feed, which was ascribed mainly to the more severe fouling resulting from tannic acid adsorption within the porous support layer of the FO membrane compared to minor alginate deposition on the membrane surface. It was found that the higher the initial flux level and cross flow velocity, the faster the flux decline with lower mixed foulants retention. It was also revealed that the calcium ions in a basic solution enhanced the combined fouling flux reduction and combined foulants retention. As the major constituent of the combined fouling layer, the adsorption of tannic acid might play a more significant role in the mixed fouling of the FO membrane, which was probably influenced by permeation drag caused by water flux and chemical interactions induced by feed solution pH and calcium ion concentration.

  7. Surface modification influencing adsorption of red wine constituents: The role of functional groups

    Energy Technology Data Exchange (ETDEWEB)

    Mierczynska-Vasilev, Agnieszka, E-mail: agnieszka.mierczynska-vasilev@awri.com.au; Smith, Paul A., E-mail: paul.smith@awri.com.au

    2016-11-15

    Highlights: • Chemical surface composition affects behaviour of wine adsorption. • SO{sub 3}H and COOH groups adsorb more of the wine nitrogen-containing compounds. • NH{sub 2} and NR{sub 3} groups encourage carbon-containing compounds adsorption. • Red wine constituents after filtration adsorbed more on NR{sub 3} and CHO surfaces. - Abstract: The adsorption of wine constituents at solid surfaces is important in applications such as filtration and membrane fouling, binding to tanks and fittings and interactions with processing aids such as bentonite. The interaction of wine constituents with surfaces is mediated through adsorbed wine components, where the type of constituents, amount, orientation, and conformation are of consequence for the surface response. This study examines the effect of surface chemical functionalities on the adsorption of red wine constituents. Plasma-polymerized films rich in amine, carboxyl, hydroxyl, formyl and methyl functional groups were generated on solid substrates whereas, glycidyltrimethylammonium chloride was covalently attached to allylamine plasma-polymer modified surface and poly(sodium styrenesulfonate) was electrostatically adsorbed to an amine plasma-polymerized surface. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy. The ability of different substrates to adsorb red wine constituents was evaluated by quartz crystal microbalance and atomic force microscopy. The results showed that substrates modified with −SO{sub 3}H and –COOH groups can adsorb more of the wine nitrogen-containing compounds whereas −NH{sub 2} and −NR{sub 3} groups encourage carbon-containing compounds adsorption. Red wine constituents after filtration were adsorbed in higher extend on −NR{sub 3} and –CHO surfaces. The –OH modified surfaces had the lowest ability to absorb wine components.

  8. THE STUDY OF THE FILTRATION EFFICIENCY OF FILTER MATERIAL

    Institute of Scientific and Technical Information of China (English)

    Jia Ruiqing; Wang Luping; Wu Xueping

    2000-01-01

    In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some important parameters of the filter material are discussed.It shows that the filtration efficiency is closely related to the diameter (d) and the size (b).In addition, by using these results and the computer program, we can analysis the relationship between the fiber structure and filter properties quantitatively.

  9. Additive Difference Schemes for Filtration Problems in Multilayer Systems

    CERN Document Server

    Ayrjan, E A; Pavlush, M; Fedorov, A V

    2000-01-01

    In the present paper difference schemes for solution of the plane filtration problem in multilayer systems are analyzed within the framework of difference schemes general theory. Attention is paid to splitting the schemes on physical processes of filtration along water-carring layers and vertical motion between layers. Some absolutely stable additive difference schemes are obtained the realization of which needs no software modification. Parallel algorithm connected with the solving of the filtration problem in every water-carring layer on a single processor is constructed. Program realization on the multi-processor system SPP2000 at JINR is discussed.

  10. Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method

    Directory of Open Access Journals (Sweden)

    Kalantari K

    2013-05-01

    Full Text Available Katayoon Kalantari,1 Mansor Bin Ahmad,1,* Kamyar Shameli,1,2,* Roshanak Khandanlou11Department of Chemistry, Universiti Putra Malaysia, Serdang, Malaysia; 2Nanotechnology and Advance Materials Department, Materials and Energy Research Center, Karaj, Alborz, Karaj, Iran*These authors contributed equally to this workAbstract: The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4 nanoparticles on talc layers using an environmentally friendly process. The Fe3O4 magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe3O4 precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94–0.93 nm; therefore, Fe3O4 nanoparticles formed on the exterior surface of talc, with an average size of 1.95–2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe3O4 nanocomposites may have potential applications in the chemical and biological industries.Keywords: nanocomposites, Fe3O4 nanoparticles, talc, powder X-ray diffraction, scanning electron microscopy

  11. Preparation and Magnetic Properties of Mn-Zn Ferrites by the Co-precipitation Method

    Institute of Scientific and Technical Information of China (English)

    LI Xue; REN Ping; ZHANG Junxi; ZHANG Lingsong; LIU Guoping

    2009-01-01

    Mn-Zn ferrites(Mn_(1-x)Zn_xFe_2O_4)with different compositions were prepared by the coprecipitation method,and the influences of such synthesis conditions as pH value,composition and volume ratio(R)of the mixed solution and NH_4HCO_3 solution on their microstructures and magnetic properties were discussed.The samples were characterized by X-ray diffraction(XRD)and magneti-zation measurement instrument.Lattice parameters and average crystalline size of the synthesized materials were calculated from the corresponding XRD patterns with the related software Jade.5.For samples of different pH values,only one phase was found when pH values were 7.0,8.0 and 9.0.The sample with pH value of 7.0 exhibited the highest saturation magnetic induction,the lowest coercive force,and crystallized best.For samples of different R values with pH value of 7.0,only one phase was observed in all samples,and the sample with R value of 2.3 exhibited the highest saturation magnetic induction and the lowest coercive force.The composition has mainly afected the magnetic properties,and the saturation magnetic induction increases with the increase of the content of Zn(x),but decreases when x is beyond 0.6.The trend of coercive force is on the contrary.However,no magnetism is ex-hibited when the x value is up to 0.8.

  12. Filtration performance of microporous ceramic supports.

    Science.gov (United States)

    Belouatek, Aissa; Ouagued, Abdellah; Belhakem, Mustapha; Addou, Ahmed

    2008-04-24

    The use of inorganic membranes in pollution treatment is actually limited by the cost of such membranes. Advantages of inorganic membranes are their chemical, thermal and pH properties. The purpose of this work was the development of microporous ceramic materials based on clay for liquid waste processing. The supports or ceramic filters having various compositions were prepared and thermally treated at 1100 degrees C. The results show that, at the temperature studied, porosity varied according to the support composition from 12% for the double-layered (ceramic) support to 47% for the activated carbon- filled support with a mean pore diameter between 0.8 and 1.3 microm, respectively. Volumes of 5 l of distilled water were filtered tangentially for 3 h under an applied pressure of 3.5 and 5.5 bar. The retention of tubular supports prepared was tested with molecules of varying size (Evans blue, NaCl and Sacharose). The study of the liquid filtration and flow through these supports showed that the retention rate depends on support composition and pore diameter, and solute molecular weight. The S1 support (mixture of barbotine and 1% (w/w) activated carbon) gave a flux for distilled water of 68 L/m2 h while the double-layered support resulted in a flux of 8 L/m2 h for the same solution at the pressure of 3.5 bar. At a pressure of 5.5 bar an increase in the distilled water flux through the various supports was observed. It was significant for the S1 support (230 L/m h).

  13. Water quality and treatment of river bank filtrate

    NARCIS (Netherlands)

    De Vet, W.W.J.M.; Van Genuchten, C.C.A.; Van Loosdrecht, M.C.M.; Van Dijk, J.C.

    2009-01-01

    In drinking water production, river bank filtration has the advantages of dampening peak concentrations of many dissolved components, substantially removing many micropollutants and removing, virtually completely, the pathogens and suspended solids. The production aquifer is not only fed by the

  14. Water quality and treatment of river bank filtrate

    NARCIS (Netherlands)

    De Vet, W.W.J.M.; Van Genuchten, C.C.A.; Van Loosdrecht, M.C.M.; Van Dijk, J.C.

    2010-01-01

    In drinking water production, river bank filtration has the advantages of dampening peak concentrations of many dissolved components, substantially removing many micropollutants and removing, virtually completely, the pathogens and suspended solids. The production aquifer is not only fed by the

  15. Granular bed filtration of high temperature biomass gasification gas.

    Science.gov (United States)

    Stanghelle, Daniel; Slungaard, Torbjørn; Sønju, Otto K

    2007-06-18

    High temperature cleaning of producer gas from biomass gasification has been investigated with a granular filter. Field tests were performed for several hours on a single filter element at about 550 degrees C. The results show cake filtration on the granular material and indicate good filtration of the biomass gasification producer gas. The relatively low pressure drop over the filter during filtration is comparable to those of bag filters. The granular filter can operate with high filtration velocities compared to bag filters and maintain high efficiency and a low residual pressure. This work is a part of the BioSOFC-up project that has a goal of utilizing the producer gas from the gasification plant in a solid oxide fuel cell (SOFC). The BioSOFC-up project will continue to the end of 2007.

  16. Effect of lithium therapy on glomerular filtration rate.

    Science.gov (United States)

    Decina, P; Oliver, J A; Sciacca, R R; Colt, E; Fieve, R R

    1983-08-01

    Patients taking lithium had a slightly higher serum creatinine concentration than controls. Creatinine concentration was independent of lithium level or therapy length, suggesting that lithium decreases glomerular filtration but that this effect is small, noncumulative, and of marginal clinical significance.

  17. Performance of multistage filtration using different filter media ...

    African Journals Online (AJOL)

    Performance of multistage filtration using different filter media against conventional water treatment systems. ... horizontal flow roughing filter (HRF)) as an alternative water treatment technology to the conventional one. A pilot- ... Article Metrics.

  18. Scaling and particulate fouling in membrane filtration systems

    NARCIS (Netherlands)

    Boerlage, S.F.E.

    2001-01-01

    Membrane filtration technologies have emerged as cost competitive and viable techniques in drinking and industrial water production. Despite advancements in membrane manufacturing and technology, membrane scaling and fouling remain major problems and may limit future growth in the industry. Scaling

  19. Advanced treatment of WWTP effluent with filtration leading to a pretreatment technique for membrane filtration.

    Science.gov (United States)

    Scherrenberg, S M; te Kloeze, A M; Janssen, A N; van Nieuwenhuijzen, A F; Menkveld, H W H; Bechger, M; van der Graaf, J H J M

    2010-01-01

    In 2000 the European Union introduced the Water Framework Directive (WFD). The aim of the WFD is having an ecological and chemical balance for all surface waters in Europe in 2015. The European Commission identified 33 priority substances and their maximum allowable concentrations, FHI-values (Fraunhofer Institute), which are specified in the Annex of the WFD. The objective of this research is to achieve the removal of suspended solids, nitrogen and total phosphorus together with priority substances. All these substances will be removed in one filter called a "One Step Total Effluent Polishing filter" i.e. 1-STEP(®) filter. For this purpose a filter pilot plant was tested at the WWTP Horstermeer. The results show that the filter can fulfil the target values in the filtrate water for total nitrogen (2.2 mg Ntotal/L) and total phosphorus (0.15 mg Ptotal/L). The majority of the priority (hazardous) substances in the WWTP effluent are already below the detection limit. Due to the low concentration ranges, the results on the removal of medicine and pesticides are only indicative. A decreasing tendency in the removal efficiency is shown for all measured compounds. The average specific ultrafiltration resistance (SUR) value decrease of the filter is 55% and the final value is always below 5·10(12) m(-2). This indicates that the filtrate water of the filter is very well filterable and can be used as ultrafiltration feedwater.

  20. Preparation of Chitosan Coated Magnetic Hydroxyapatite Nanoparticles and Application for Adsorption of Reactive Blue 19 and Ni2+ Ions

    Directory of Open Access Journals (Sweden)

    Van Cuong Nguyen

    2014-01-01

    Full Text Available An adsorbent called chitosan coated magnetic hydroxyapatite nanoparticles (CS-MHAP was prepared with the purpose of improvement for the removal of Ni2+ ions and textile dye by coprecipitation. Structure and properties of CS-MHAP were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and vibrating sample magnetometer (VSM. Weight percent of chitosan was investigated by thermal gravimetric analysis (TGA. The prepared CS-MHAP presents a significant improvement on the removal efficiency of Ni2+ ions and reactive blue 19 dye (RB19 in comparison with chitosan and magnetic hydroxyapatite nanoparticles. Moreover, the adsorption capacities were affected by several parameters such as contact time, initial concentration, adsorbent dosage, and initial pH. Interestingly, the prepared adsorbent could be easily recycled from an aqueous solution by an external magnet and reused for adsorption with high removal efficiency.

  1. Supercritical CO2 Assisted Synthesis of EDTA-Fe3O4 Nanocomposite with High Adsorption Capacity for Hexavalent Chromium

    Directory of Open Access Journals (Sweden)

    Gunjan Bisht

    2016-01-01

    Full Text Available Efficiency of EDTA functionalized nanoparticles in adsorption of chromium (VI from water was investigated in this study. Magnetic iron oxide nanoparticles (IONPs were synthesized by a simple chemical coprecipitation route and EDTA coating onto IONPs was attained via supercritical carbon dioxide (Sc CO2, a technology with green sustainable properties. The obtained nanoparticles were then characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR, X-ray powder diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and vibrating magnetometric analysis (VSM. The synthesized nanoparticle and its modified variant were evaluated as adsorbent for chromium (VI removal from water through batch adsorption technique and the effect of analytic concentration; contact time and adsorbent concentration were studied at pH 2. The results showed higher removal efficiency for modified magnetic iron oxide nanoparticles (MIONPs (i.e., 99.9% than their nonmodified variant IONPs, that is, 34.06% for the same concentration after 18 hours of incubation. Also maximum adsorption capacity (qe = 452.26 mg/g of MIONPs attained can be related to their preparation in Sc CO2 as qe calculated from IONPs, that is, 170.33 mg/g, is lower than that of MIONPs. The adsorption data fit well with Freundlich isotherm equation while kinetic adsorption studies of chromium (VI were modeled by pseudo-second-order model.

  2. Ultrafiltration Enhanced with Activated Carbon Adsorption for Efficient Dye Removal from Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    董亚楠; 苏延磊; 陈文娟; 彭金明; 张岩; 姜忠义

    2011-01-01

    In this study, orange G dye was efficiently removed from aqueous solution by ultraflltration (UF) membrane separation enhanced with activated carbon adsorption. The powdered activated carbon (PAC) was deposited onto the UF membrane surface, forming an intact filter cake. The enhanced UF process simultaneously exploited the high water permeation flux of porous membrane and the high adsorption ability of PAC toward dye molecules. The influencing factors on the dye removal were investigated. The results indicated that with sufficient PAC incorporation, the formation of intact PAC filtration cake led to nearly complete rejection for dye solution under opti-mized dye concentration and operation pressure, without large sacnticlng the permeation tlux ot the filtration process. Typically, the dye rejection ratio increased from 43.6% for single UF without adsorption to nearly 100% for the enhanced UF process, achieving long time continuous treatment with water permeation flux of 47 L·m^-2·h^-1. The present study demonstrated that adsorption enhanced UF may be a feasible method for the dye wastewater treatment.

  3. Low-cost magnetic adsorbent for As(III) removal from water: adsorption kinetics and isotherms.

    Science.gov (United States)

    Kango, Sarita; Kumar, Rajesh

    2016-01-01

    Magnetite nanoparticles as adsorbent for arsenic (As) were coated on sand particles. The coated sand was used for the removal of highly toxic element 'As(III)' from drinking water. Here, batch experiments were performed with the variation of solution pH, adsorbent dose, contact time and initial arsenic concentration. The adsorbent showed significant removal efficiency around 99.6 % for As(III). Analysis of adsorption kinetics revealed that the adsorbent follows pseudo-second-order kinetics model showing R (2) = 0.999, whereas for pseudo-first-order kinetics model, the value of R (2) was 0.978. In the case of adsorption equilibrium, the data is well fitted with Langmuir adsorption isotherm model (R (2) > 0.99), indicating monolayer adsorption of As(III) on the surface of adsorbent. The existence of commonly present ions in water influences the removal efficiency of As(III) minutely in the following order PO4 (3-) > HCO3 (-) > Cl(-) > SO4 (2-). The obtained adsorbent can be used to overcome the problem of water filtration in rural areas. Moreover, as the nano-magnetite is coated on the sand, it avoids the problem of extraction of nanoparticles from treated water and can easily be removed by a simple filtration process.

  4. Effect of Nanofibers on Spore Penetration and Lunar Dust Filtration

    OpenAIRE

    Phil Gibson, Ph.D.; Heidi Schreuder-Gibson, Ph.D.; Robert Stote; Margaret Roylance, Ph.D.; Cathy Capone; Masami Nakagawa, Ph.D.

    2008-01-01

    The results of two separate studies on biological spore penetration and simulated lunar dust filtration illustrate the use of nanofibers in some nonstandard filtration applications (nanofibers are generally defined as having diameters of less than a micron). In the first study, a variety of microporous liners containing microfibers and nanofibers were combined with cotton-based fabrics in order to filter aerosolized spores. The aerosol penetration resistance of the nanofiber-lined fabrics was...

  5. Water Clarity Simulant for K East Basin Filtration Testing

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Andrew J.

    2006-01-20

    This document provides a simulant formulation intended to mimic the behavior of the suspended solids in the K East (KE) Basin fuel storage pool. The simulant will be used to evaluate alternative filtration apparatus to improve Basin water clarity and to possibly replace the existing sandfilter. The simulant was formulated based on the simulant objectives, the key identified parameters important to filtration, the composition and character of the KE Basin suspended sludge particles, and consideration of properties of surrogate materials.

  6. Pesticide removal by combined ozonation and granular activated carbon filtration

    OpenAIRE

    Orlandini, E.

    1999-01-01

    Since the seventies, new water treatment processes have been introduced in the production of drinking water from surface water. Their major aim was to adequately cope with the disinfection of this water, and/or with the removal of pesticides and other organic micropollutants from it. This research focused on Biological Activated Carbon (BAC) filtration, which is a combination of ozonation and GAC filtration. Its general goal was identification and understanding of the mechanisms that underlie...

  7. Filtration ATF in automatic transmissions (AT) of cars

    OpenAIRE

    Tadeusz Dziubak; Paweł Szczepaniak

    2014-01-01

    Functions and conditions of work of suction ATF filters are presented. Requirements ofATF filters are discussed. Sources of contaminations ATF are presented. ATF filtration system wascharacterized. Classification of ATF filters and their selection of design solutions are presented. Filtermaterials used for the production of ATF suction filters are presented and characterized. Conditions ofthe work of suction ATF filters were analyzed. Hydraulic and filtration characteristics are discussed.[b]...

  8. Sampling Rate Independent Filtration Approach for Automatic ECG Delineation

    CERN Document Server

    Chereda, Hryhorii; Tymoshenko, Yury

    2016-01-01

    In this paper different types of ECG automatic delineation approaches were overviewed. A combination of these approaches was used to create sampling rate independent filtration algorithm for automatic ECG delineation that is capable of distinguishing different morphologies of T and P waves and QRS complexes. Created filtration algorithm was compared with algorithme \\`a trous. It was investigated that continuous wavelets transform with proposed automatic adaptation for different sampling rates procedure can be used for delineation problem.

  9. Characterization and modification of particulate properties to enhance filtration performance

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, T.R.; Vann Bush, P.; Robinson, M.S.

    1990-06-01

    The specific objectives of this project are to characterize the particulate properties that determine the filtration performance of fabric filters, and to investigate methods for modifying these particulate properties to enhance filtration performance. Inherent in these objectives is the development of an experimental approach that will lead to full-scale implementation of beneficial conditioning processes identified during the project. The general approach has included a large number of laboratory evaluations to be followed by optional field tests of a new successful conditioning processes performed on a sidestream device. This project was divided into five tasks. The schedule followed for these tasks is shown in Figure 4. Tasks 2 and 3 each focus on one of the two complementary parts of the project. Task 2 Parametric Tests of Ashes and Fabrics, evaluates the degree to which ash properties and fabric design determine filtration performance. Task 3 Survey of Methods to Modify the Particle Filtration Properties, provides a literature review and laboratory study of techniques to modify ash properties. The results of these two tasks were used in Task 4 Proof-of-Concept Tests of Methods to Modify Particle Filtration Properties to demonstrate the effects on filtration performance of modifying ash properties. The findings of all the tasks are summarized in this Final Report. 13 refs.

  10. Wind Turbine Gearbox Oil Filtration and Condition Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Shuangwen

    2015-10-25

    This is an invited presentation for a pre-conference workshop, titled advances and opportunities in lubrication: wind turbine, at the 2015 Society of Tribologists and Lubrication Engineers (STLE) Tribology Frontiers Conference held in Denver, CO. It gives a brief overview of wind turbine gearbox oil filtration and condition monitoring by highlighting typical industry practices and challenges. The presentation starts with an introduction by covering recent growth of global wind industry, reliability challenges, benefits of oil filtration and condition monitoring, and financial incentives to conduct wind operation and maintenance research, which includes gearbox oil filtration and condition monitoring work presented herein. Then, the presentation moves on to oil filtration by stressing the benefits of filtration, discussing typical main- and offline-loop practices, highlighting important factors considered when specifying a filtration system, and illustrating real-world application challenges through a cold-start example. In the next section on oil condition monitoring, a discussion on oil sample analysis, oil debris monitoring, oil cleanliness measurements and filter analysis is given based on testing results mostly obtained by and at NREL, and by pointing out a few challenges with oil sample analysis. The presentation concludes with a brief touch on future research and development (R and D) opportunities. It is hoping that the information presented can inform the STLE community to start or redirect their R and D work to help the wind industry advance.

  11. C*-Algebras over Topological Spaces: Filtrated K-Theory

    CERN Document Server

    Meyer, Ralf

    2008-01-01

    We define the filtrated K-theory of a C*-algebra over a finite topological space X and explain how to construct a spectral sequence that computes the bivariant Kasparov theory over X in terms of filtrated K-theory. For finite spaces with totally ordered lattice of open subsets, this spectral sequence becomes an exact sequence as in the Universal Coefficient Theorem, with the same consequences for classification. We also exhibit an example where filtrated K-theory is not yet a complete invariant. We describe a space with four points and two C*-algebras over this space in the bootstrap class that have isomorphic filtrated K-theory but are not KK(X)-equivalent. For this particular space, we enrich filtrated K-theory by another K-theory functor, so that there is again a Universal Coefficient Theorem. Thus the enriched filtrated K-theory is a complete invariant for purely infinite, stable C*-algebras with this particular spectrum and belonging to the appropriate bootstrap class.

  12. Membrane filtration immobilization technique-a simple and novel method for primary isolation and enrichment of bacteriophages.

    Science.gov (United States)

    Ghugare, G S; Nair, A; Nimkande, V; Sarode, P; Rangari, P; Khairnar, K

    2017-02-01

    To develop a method for the isolation and enrichment of bacteriophages selectively against specific bacteria coupled with a membrane filtration technique. Rapid isolation and concentration of host-specific bacteriophages was achieved by exposure of the sample suspected to contain bacteriophages to a specific host immobilized on a 0·45 μm membrane in a membrane filtration unit. The principle behind this method is the exploitation of host-specific interaction of bacteriophages with their host and maximizing this interaction using a classic membrane filtration method. This provides a chance for each bacteriophage in the sample to interact with the specific host on the membrane filter fitted with a vacuum pump. Specific bacteriophages of the host are retained on the membrane along with its host cells due to the effect of adsorption and these adsorbed bacteriophages (along with their hosts) on the filter disc are then amplified and enriched in regular nutritive broth tryptose soya broth by incubation. With the help of the plaque assay method, host-specific phages of various bacterial species were isolated, segregated and enriched. The phage concentration method coupled with membrane filtration immobilization of host bacteria was able to isolate and enrich the host-specific bacteriophages by several fold using a lower quantity of an environmental water sample, or other phage suspensions. Enrichment of phages from single plaques was also achieved. The isolation and detection of host-specific bacteriophages from a low density bacteriophage water sample in a single step by the use of a simple and basic microbiological technique can be achieved. Enrichment of phages from low phage titre suspensions is also achieved very effectively. © 2016 The Society for Applied Microbiology.

  13. Improved Aeration Process - Catalytic Role Of The Iron Oxides In Arsenic Oxidation And Coprecipitation

    DEFF Research Database (Denmark)

    Kowalski, Krysztof; Søgaard, Erik Gydesen

    2013-01-01

    an improved aeration process that can also help in developing better arsenic removal treatment. The results present advantages of arsenic oxidation in an aeration process in the presence of ferrihydrite surface that have been shown to adsorb arsenic simultaneously to its oxidation. The presence...... of precipitated (ferrihydrite surface) and dissolved iron enhanced arsenic oxidation in comparison to solution with absence of precipitated iron in laboratory scale experiments. However, in the pilot scale studies the adsorption of arsenite on ferrihydrite was found to be the main process occurring during...... implementation of the process in the waterworks that are struggling with arsenic related issues....

  14. PREPARATION MICRO-FILTRATION CERAMIC MEMBRANE FROM NATURAL ZEOLITE FOR PROCION RED MX8B AND METHYLENE BLUE FILTRATION

    Directory of Open Access Journals (Sweden)

    Dyah Choiriyah

    2015-12-01

    Full Text Available The study of ceramic membrane fabrication from natural zeolite and its utilization for filtration of procion red MX8B and methylene blue has been investigated. The purposes of this study are to determine the effect of pressure on membrane permeability and selectivity and utilize natural zeolite as ceramic membranes procion red MX8B and methylene blue filtration. The membrane was prepared by metide press pellets and then calcined at 850 oC. The membranes were characterized by mechanical test, flux and rejection of dye. The compression test of the membrane found the values of 1369.178 psi in dry conditions to 1388.933 psi in wet conditions. The flux test found that the higher the pressure applied, the flux was increase. However, the high pressure also decreased the selectivity. Rejection test found that the rejection of methylene blue filtration up to 70 %. Meanwhile, procion red MX8B filtration has rejectivity less than 20 %.

  15. Carbon nanotube membranes with ultrahigh specific adsorption capacity for water desalination and purification.

    Science.gov (United States)

    Yang, Hui Ying; Han, Zhao Jun; Yu, Siu Fung; Pey, Kin Leong; Ostrikov, Kostya; Karnik, Rohit

    2013-01-01

    Development of technologies for water desalination and purification is critical to meet the global challenges of insufficient water supply and inadequate sanitation, especially for point-of-use applications. Conventional desalination methods are energy and operationally intensive, whereas adsorption-based techniques are simple and easy to use for point-of-use water purification, yet their capacity to remove salts is limited. Here we report that plasma-modified ultralong carbon nanotubes exhibit ultrahigh specific adsorption capacity for salt (exceeding 400% by weight) that is two orders of magnitude higher than that found in the current state-of-the-art activated carbon-based water treatment systems. We exploit this adsorption capacity in ultralong carbon nanotube-based membranes that can remove salt, as well as organic and metal contaminants. These ultralong carbon nanotube-based membranes may lead to next-generation rechargeable, point-of-use potable water purification appliances with superior desalination, disinfection and filtration properties.

  16. Expanded-bed adsorption utilizing ion-exchange resin to purify extracellular beta-galactosidase.

    Science.gov (United States)

    Pereira, J A; Vieira E Rosa, P De T; Pastore, G M; Santana, C C

    1998-01-01

    The application of expanded-bed ion-exchange resins allows the elimination of intermediary particulate separation steps like filtration or centrifugation prior to adsorption steps in enzyme-purification processes from crude fermentation broths. This work is concerned with the experimental evaluation data of a process related to the adsorption of an extracellular p-galactosidase from the fungi Scopulariopsis. The protein recovery in the ion-exchange resin Accell Plus QMA was accomplished using a continuous-monitoring method. The direct adsorption step was followed by a elution step with concentrated NaCl solutions aiming to improve the enzyme-specific activity. Experimental data for fixed and expanded bed were compared.

  17. Copper adsorption in tropical oxisols

    Directory of Open Access Journals (Sweden)

    Silveira Maria Lucia Azevedo

    2003-01-01

    Full Text Available Cu adsorption, at concentrations between 0 to 800 mg L-1, was evaluated in surface and subsurface samples of three Brazilian soils: a heavy clayey-textured Rhodic Hapludalf (RH, a heavy clayey-textured Anionic ''Rhodic'' Acrudox (RA and a medium-textured Anionic ''Xanthic'' Acrudox (XA. After adsorption, two consecutive extractions were performed to the samples which received 100 mg L-1 copper. Surface samples adsorbed higher amounts of Cu than the subsurface, and exhibited lower Cu removed after the extractions, reinforcing the influence of the organic matter in the reactions. Cu adsorption was significant in the subsurface horizons of the Oxisols, despite the positive balance of charge, demonstrating the existence of mechanisms for specific adsorption, mainly related to the predominance of iron and aluminum oxides in the mineral fractions. In these samples, Cu was easily removed from the adsorption sites. RH demonstrated a higher capacity for the Cu adsorption in both horizons.

  18. Chromium (VI) adsorption on boehmite

    Energy Technology Data Exchange (ETDEWEB)

    Granados-Correa, F. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027 Col., Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)], E-mail: fgc@nuclear.inin.mx; Jimenez-Becerril, J. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027 Col., Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)

    2009-03-15

    Boehmite was synthesized and characterized in order to study the adsorption behavior and the removal of Cr(VI) ions from aqueous solutions as a function of contact time, initial pH solution, amount of adsorbent and initial metal ion concentration, using batch technique. Adsorption data of Cr(VI) on the boehmite were analyzed according to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption models. Thermodynamic parameters for the adsorption system were determinated at 293, 303, 313 and 323 K temperatures. The kinetic values and thermodynamic parameters from the adsorption process show that the Cr(VI) ions adsorption on boehmite is an endothermic and spontaneous process. These results show that the boehmite could be considered as a potential adsorbent for chromium ions in aqueous solutions.

  19. Adsorption of proteins from plasma at polyester non-wovens.

    Science.gov (United States)

    Klomp, A J; Engbers, G H; Mol, J; Terlingen, J G; Feijen, J

    1999-07-01

    Polyester non-wovens in filters for the removal of leukocytes from platelet concentrates (PCs) must be platelet compatible. In PC filtration, the adsorption of proteins at the plasma-non-woven interface can be of great importance with respect to the yield of platelets. Unmodified and radio frequency glow discharge (RFGD) treated poly(ethylene terephthalate) non-woven (NW-PET) and two commercial surface-modified non-wovens were contacted with human plasma. Protein desorption by sodium dodecyl sulphate (SDS) was evaluated by X-ray photoelectron spectroscopy (XPS). The desorbed proteins were characterized by gel electrophoresis and immunoblotting. Compared to the commercial surface-modified non-wovens, unmodified and RFGD-treated NW-PETs adsorbed a relatively high amount of protein. Significantly more protein was removed from the hydrophobic NW-PET by SDS than from the hydrophilic RFGD-treated non-wovens. RFGD treatment of NW-PET reduces the reversibility of protein adsorption. Less albumin and fibrinogen were removed from the RFGD-treated non-wovens than from NW-PET. In addition, a large amount of histidine-rich glycoprotein was removed from RFGD-treated non-wovens, but not from NW-PET. The different behaviour of RFGFD-treated non-wovens towards protein adsorption is probably caused by differences in the chemical reactivity of the non-woven surfaces.

  20. Adsorption design for wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cooney, D.O.

    1998-12-31

    Understand the premier method for removing organic contaminants from water. Straight forward explanations and illustrations allow this overview to fill a dual purpose: study manual and design guide. The book discusses basic properties of activated carbons; explains the kinetics of adsorption processes; describes the design of both fixed-bed and batch process adsorption systems; contains useful knowledge that can be extended to other applications of adsorption, including drinking water treatment; and includes many illustrated examples and practice exercises.

  1. Stability of arsenate-bearing Fe(III)/Al(III) co-precipitates in the presence of sulfide as reducing agent under anoxic conditions.

    Science.gov (United States)

    Doerfelt, Christoph; Feldmann, Thomas; Roy, Ranjan; Demopoulos, George P

    2016-05-01

    Currently, the co-precipitation of arsenate with ferric iron at molar ratios Fe(III)/As(V) ≥ 3 by lime neutralization produces tailings solids that are stable under oxic conditions. However not much is known about the stability of these hazardous co-precipitates under anoxic conditions. These can develop in tailings storage sites by the action of co-discharged reactive sulfides, organic reagent residuals or bacterial activity. The ferric matrix can then undergo reductive dissolution reactions, which could release arsenic into the pore water. Co-ions like aluminum could provide a redox-immune sink to scavenge any mobilized arsenic as a result of reduction of ferric. As such, in this work Fe(III)/As(V) = 4 and aluminum substituted Fe(III)/Al(III)/As(V) = 2/2/1 co-precipitates were produced in a mini continuous co-precipitation process circuit and subjected to excess sulfide addition under inert gas to evaluate their stability. It was found that the ferric-arsenate co-precipitate could retain up to 99% (30 mg/L in solution) of its arsenic content despite the high pH (10.5) and extremely reducing (Eh ferric iron was reduced. Partial aluminum substitution was found to cut the amount of mobilized arsenic by 50% (down to 15 mg/L) hence mixed Fe(III)/Al(III)-arsenate co-precipitates may offer better resistance to reductive destabilization over the long term than all iron co-precipitates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Removal of bisphenol A by adsorption mechanism using PES-SiO2 composite membranes.

    Science.gov (United States)

    Muhamad, Mimi Suliza; Salim, Mohd Razman; Lau, Woei Jye; Hadibarata, Tony; Yusop, Zulkifli

    2016-08-01

    Polyethersulphone (PES) membranes blended with silicon dioxide (SiO2) nanoparticles were prepared via a dry-jet wet spinning technique for the removal of bisphenol A (BPA) by adsorption mechanism. The morphology of SiO2 nanoparticles was analysed using a transmission electron microscopy and particle size distribution was also analysed. The prepared membranes were characterized by several techniques including field emission scanning electron microscopy, Fourier transform infrared spectroscopy and water contact angle. The adsorption mechanism of membrane towards BPA was evaluated by batch experiments and kinetic model. The influence of natural organic matter (NOM) in feed water on membrane BPA removal was also studied by filtration experiments. Results showed that BPA adsorption capacity as high as 53 µg/g could be achieved by the PES membrane incorporated with 2 wt% SiO2 in which the adsorption mechanism was in accordance with the pseudo-second-order kinetic model. The intraparticles diffusion model suggested that the rate limiting factor of membrane adsorption mechanism is governed by the diffusion of BPA into the membrane pores. The presence of 10 ppm NOM has reported to negatively reduce BPA removal by 24%, as it tended to compete with BPA for membrane adsorption. This work has demonstrated that PES-SiO2 membrane has the potential to eliminate trace amount of BPA from water source containing NOM.

  3. Removal of chloramphenicol by macroporous adsorption resins in honey: a novel approach on reutilization of antibiotics contaminated honey.

    Science.gov (United States)

    Cheng, Ni; Gao, Hui; Deng, Jianjun; Wang, Bini; Xu, Ruihan; Cao, Wei

    2012-09-01

    The effects of different steps in honey production on chloramphenicol (CAP) levels and CAP removal from honey using macroporous adsorption resins (MARs) were investigated in this study. CAP residues in honey were quantified by enzyme-linked immunosorbent assay after each processing step including preheating, filtration, vacuum concentration and pasteurization. Vacuum concentration contributes the most reduction of CAP level (9.9%). Meanwhile, 5 types of MARs (including LSI-1, LSI-2, LSI-3, LS-803, and LS-903) were used in CAP adsorption. The results showed that LS-803 resin had higher adsorption rate of 86% than other resins in removing CAP from honey, and its optimal adsorption time and temperature were 40 min and 55 °C, respectively. The treated honey could be used as feed additive or biomass energy. Therefore, it would be a novel approach to reutilization of antibiotics contaminated honey.

  4. Magnetite nanoparticles prepared by co-precipitation method in different conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aphesteguy, J.C., E-mail: caphestegu@fi.uba.ar [LAFMACEL-INTECIN, Facultad de Ingeniería, UBA, Paseo Colón 850, C1063EHA Buenos Aires (Argentina); Kurlyandskaya, G.V. [Universidad del País Vasco UPV-EHU, Dept. Electricidad y Electronica, 48940 Leioa (Spain); Ural Federal University, Dept. Magnetism and Magnetic Nanomaterials, 620000 Ekaterinburg (Russian Federation); Celis, J.P. de [National Technology University (UTN), Facultad Regional Avellaneda, Department of Chemistry (Argentina); Safronov, A.P. [Ural Federal University, Dept. Magnetism and Magnetic Nanomaterials, 620000 Ekaterinburg (Russian Federation); Institute of Electrophysics UD RAS, Ekaterinburg 620016 (Russian Federation); Schegoleva, N.N. [Institute of Metal Physics UD RAS, Ekaterinburg 620044 (Russian Federation)

    2015-07-01

    Magnetic nanoparticles (MNPs) of pure magnetite (Fe{sub 3}O{sub 4}) were prepared in an aqueous solution (sample M−I) and in a water-ethyl alcohol mixture (sample M−II) by the co-precipitation method. The structure and magnetic properties of both samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), magnetic (M−H) and microwave measurements (FMR). The mean average particle diameter and particle size distribution was evaluated by the Dynamic Light Scattering (DLS) and Brunauer- Emmett-Teller techniques (BET). The Quantitative chemical analysis of iron was performed by Inductively Coupled Plasma (ICP)- Atomic Emission Spectroscopy (AES) technique. The MNPs prepared in aqueous solution show a higher grain than those prepared in the water-ethyl alcohol mixture. The type of phase structure in both cases can be defined as “defective spinel”. The shape of the majority of M−I MNPs is octahedral. The shape of the majority of M−II MNPs is cubic. The specific surface area of MNPs was as high as 14.4 m{sup 2}/g for M−I sample and 77.8 m{sup 2}/g for sample M–II. The obtained saturation magnetization values of 75 emu/g (M−I) and 68 emu/g (M−II) are consistent with expected values for magnetite MNPs of observed sizes. Ferromagnetic resonance (FMR) measurements confirmed that MNPs of both types are magnetically homogeneous materials. FMR lines' position and line widths can be understood by invoking the local dipolar fields, deviations from sphericity, magnetocrystalline anisotropy and stresses. M−I sample shows sizeable zero field microwave absorption which is absent in the M−II case. The differences in microwave behaviour of M−I and M−II MNPs can be used in the design of microwave radiation absorbing multilayers. - Highlights: • Magnetite nanoparticles were prepared in two different conditions. • Specific surface area of sample prepared in water- ethanol mix is

  5. Co-precipitation of copper and niobium carbide in a low carbon steel

    Science.gov (United States)

    Gagliano, Michael Scott

    Co-precipitation of niobium carbide and body-centered cubic (BCC) copper in ferrite was investigated as a high strength, low carbon, chromium-free alternative to conventional high performance structural steels that rely on a tempered martensitic microstructure. Theoretical nucleation and growth rate models for BCC copper and niobium carbide were constructed using calculated thermodynamic driving forces in conjunction with classical theories for the homogeneous nucleation and subsequent growth of coherent, spherical precipitates. The maximum calculated nucleation and growth rates for niobium carbide were found to be 1.0 x 106 nuclei/cm3s at 666°C and 1.0 nm/s at 836°C, respectively, for an austenitizing temperature of 1170°C. For BCC copper in ferrite, the maximum calculated nucleation and growth rates were determined to be 8.0 x 1015 nuclei/cm 3s at 612°C and 0.038 nm/s at 682°C, respectively, for all austenitizing temperatures. Three-dimensional atom probe (3DAP) microscopy revealed the presence of nano-scale BCC copper clusters in approximately the same number density predicted by the theoretical nucleation model. Using an experimentally determined "effective" activation energy for copper in iron, the normalized theoretical nucleation rate curve compared very well with the normalized hardness response after 5 minutes of aging and effectively described the experimental short-time aging behavior of a low carbon, niobium bearing steel. The size and morphological evolution as well as the growth and coarsening behavior of copper precipitates were investigated through conventional TEM during isothermal direct aging at 550°C for a niobium and niobium-free steel. Although niobium carbide precipitation was not characterized, niobium additions provided increased hardness upon direct aging and showed a much higher resistance to overaging, than a niobium-free steel, for long isothermal aging times. In both steels for aging times up to five hours, both 9R type and BCC

  6. Four years experience with filtration systems in commercial nurseries for eliminating Phytophthora species from recirculation water

    Science.gov (United States)

    T. Ufer; M. Posner; H.-P. Wessels; S. Wagner; K. Kaminski; T. Brand; Werres S.

    2008-01-01

    In a four year project, three different filtration systems were tested under commercial nursery conditions to eliminate Phytophthora spp. from irrigation water. Five nurseries were involved in the project. Slow sand filtration systems were tested in three nurseries. In the fourth nursery, a filtration system with lava grains (Shieer® Bio filtration)...

  7. Effect of pH value on electromagnetic loss properties of Co–Zn ferrite prepared via coprecipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaogu, E-mail: nthxg@126.com [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); School of Material Science and Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Zhang, Jing [Nanjing Center, China Geological Survey, Nanjing 210016 (China); Wang, Wei [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Sang, Tianyi [Department of Electrical and Computer Engineering, University of California Davis, Davis 95616 (United States); Song, Bo [School of Material Science and Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Zhu, Hongli [Institute 53 of China North Industries Group Corporation, Jinan 250031 (China); Rao, Weifeng [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Wong, Chingping [School of Material Science and Engineering, Georgia Institute of Technology, Atlanta 30332 (United States)

    2016-05-01

    In this paper, the cobalt zinc ferrite was prepared by coprecipitation method at different pH conditions. The influence of pH values on the coprecipitation reaction was theoretically analyzed at first. The calculated results showed that the pH values should be controlled in the range of 9–11 to form the stable precipitation. The XRD investigation was used to further confirm the formation of the composite on specific pH values. In addition, the morphological study revealed that the average particle size of the composite decreased from 40 nm to 30 nm when the pH value increased from 9–11. The variation of microstructure plays a critical role in controlling the electromagnetic properties. From the electromagnetic analysis, the dielectric loss factor was 0.02–0.07 and magnetic loss factor was 0.2–0.5 for the composite synthesized at pH of 9, which presents dramatically improved dielectric loss and magnetic loss properties than the samples prepared at pH of 10 and 11. The as-prepared cobalt zinc ferrite are highly promising to be used as microwave absorption materials. - Highlights: • Co–Zn ferrite was prepared by coprecipitation method with different pH values. • To obtain pure Co–Zn ferrite, the theoretical pH values were 9–11. • Microstructure and electromagnetic properties can be tuned by varying pH values. • Co–Zn ferrite prepared with pH=9 performed well electromagnetic loss properties.

  8. Revisiting Pocos de Caldas. Application of the co-precipitation approach to establish realistic solubility limits for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.; Duro, L.; Jordana, S.; Cera, E. [QuantiSci, Barcelona (Spain)

    1996-02-01

    Solubility limits constitute a critical parameter for the determination of the mobility of radionuclides in the near field and the geosphere, and consequently for the performance assessment of nuclear waste repositories. Mounting evidence from natural system studies indicate that trace elements, and consequently radionuclides, are associated to the dynamic cycling of major geochemical components. We have recently developed a thermodynamic approach to take into consideration the co-precipitation and co-dissolution processes that mainly control this linkage. The approach has been tested in various natural system studies with encouraging results. The Pocos de Caldas natural analogue was one of the sites where a full testing of our predictive geochemical modelling capabilities were done during the analogue project. We have revisited the Pocos de Caldas data and expanded the trace element solubility calculations by considering the documented trace metal/major ion interactions. This has been done by using the co-precipitation/co-dissolution approach. The outcome is as follows: A satisfactory modelling of the behaviour of U, Zn and REEs is achieved by assuming co-precipitation with ferrihydrite. Strontium concentrations are apparently controlled by its co-dissolution from Sr-rich fluorites. From the performance assessment point of view, the present work indicates that calculated solubility limits using the co-precipitation approach are in close agreement with the actual trace element concentrations. Furthermore, the calculated radionuclide concentrations are 2-4 orders of magnitude lower than conservative solubility limits calculated by assuming equilibrium with individual trace element phases. 34 refs, 18 figs, 13 tabs.

  9. Adsorption and collective paramagnetism

    CERN Document Server

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  10. A Continuous Procedure Based on Column Chromatography to Purify Anthocyanins from Schisandra chinensis by a Macroporous Resin plus Gel Filtration Chromatography.

    Science.gov (United States)

    Yue, Daran; Yang, Lei; Liu, Shouxin; Li, Jian; Li, Wei; Ma, Chunhui

    2016-02-06

    In our previous study, as natural food colorants and antioxidants, the color and content stabilities of Schisandra chinensis (S. chinensis) anthocyanins were investigated. In this work, the purification process parameters of S. chinensis anthocyanins using a macroporous resin and gel filtration chromatography were evaluated. The optimized parameters of static adsorption and desorption were as follows. The selected resin is HPD-300 (nonpolar copolymer styrene type resin), and the anthocyanins adsorption saturation capacity of HPD-300 resin was 0.475 mg/g dry resin. Adsorption time was 4 h, and 0.517 mg/mL of S. chinensis anthocyanins was adsorbed on the resin column with a flow rate of 39 mL/h (3 BV/h). After adsorption, the anthocyanins were completely desorpted with 2.5 BV of 90% (v/v) ethanol solution, and the desorption flow rate was 13 mL/h (1 BV/h). After purification by dynamic adsorption and desorption, the anthocyanins content in the effluent increased from 47.6 mg/g to 128.4 mg/g, the purity of anthocyanins increased six-fold from 5.08% to 30.43%, and the anthocyanins recovery was 96.5%. The major constituent of S. chinensis anthocyanins was isolated with Bio-Gel P2 gel filtration chromatography, and it was detected by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS) as cyanidin-3-O-xylosylrutinoside. Moreover, the antioxidant activities of S. chinensis anthocyanins were investigated. After purification using the HPD-300 resin, the antioxidant activities of anthocyanins were increased 1.2-fold (FRAP) and 1.7-fold (ABTS).

  11. A Continuous Procedure Based on Column Chromatography to Purify Anthocyanins from Schisandra chinensis by a Macroporous Resin plus Gel Filtration Chromatography

    Directory of Open Access Journals (Sweden)

    Daran Yue

    2016-02-01

    Full Text Available In our previous study, as natural food colorants and antioxidants, the color and content stabilities of Schisandra chinensis (S. chinensis anthocyanins were investigated. In this work, the purification process parameters of S. chinensis anthocyanins using a macroporous resin and gel filtration chromatography were evaluated. The optimized parameters of static adsorption and desorption were as follows. The selected resin is HPD-300 (nonpolar copolymer styrene type resin, and the anthocyanins adsorption saturation capacity of HPD-300 resin was 0.475 mg/g dry resin. Adsorption time was 4 h, and 0.517 mg/mL of S. chinensis anthocyanins was adsorbed on the resin column with a flow rate of 39 mL/h (3 BV/h. After adsorption, the anthocyanins were completely desorpted with 2.5 BV of 90% (v/v ethanol solution, and the desorption flow rate was 13 mL/h (1 BV/h. After purification by dynamic adsorption and desorption, the anthocyanins content in the effluent increased from 47.6 mg/g to 128.4 mg/g, the purity of anthocyanins increased six-fold from 5.08% to 30.43%, and the anthocyanins recovery was 96.5%. The major constituent of S. chinensis anthocyanins was isolated with Bio-Gel P2 gel filtration chromatography, and it was detected by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS as cyanidin-3-O-xylosylrutinoside. Moreover, the antioxidant activities of S. chinensis anthocyanins were investigated. After purification using the HPD-300 resin, the antioxidant activities of anthocyanins were increased 1.2-fold (FRAP and 1.7-fold (ABTS.

  12. Synthesis of cubic yttrium aluminum garnet (YAG) powders by co-precipitation and two-step calcinations

    Science.gov (United States)

    Girish, H. N.; Zhu, C.; Ma, F. F.; Shao, G. Q.

    2017-04-01

    YAG powders were synthesized by co-precipitation and two-step moderate calcinations at 600/800 °C or 600/900 °C in air, respectively. Two kinds of the synthesized powders both possess pure cubic YAG phases without any secondary phases such as YAH, YAP and YAM, etc.. The former has low agglomeration with nano-sized primary particles and large active energy, and the latter has homogeneously dispersed and well-crystallized particles, with a narrow particle size distribution of 8 - 13 µm.

  13. Solid-state 29Si NMR and FTIR analyses of lignin-silica coprecipitates

    DEFF Research Database (Denmark)

    Cabrera Orozco, Yohanna; Cabrera, Andrés; Larsen, Flemming Hofmann;

    2016-01-01

    When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been...... in the distribution of silanol hydroxyl groups among different coprecipitates. These differences are dependent on the lignin type. The results are interpreted that the underlying mechanism of the interactions is the formation of hydrogen bonds between lignin aliphatic hydroxyl or carboxyl groups and the silanols...

  14. Synthesis and Bactericidal Ability of TiO2 and Ag-TiO2 Prepared by Coprecipitation Method

    OpenAIRE

    Robert Liu; Wu, H. S.; Ruth Yeh; Lee, C Y; Yungtse Hung

    2012-01-01

    Preparation of photocatalysts of TiO2 and Ag-TiO2 was carried out by coprecipitation method. The prepared photocatalysts were characterized by X-ray diffraction (XRD), SEM, EDX, and XRF analysis. The disinfection of E. coli, a model indicator organism for the safe water supply, was investigated by using TiO2 and Ag-TiO2 under different light sources. The treatment efficacy for the inactivation of E. coli would be UV/Ag-TiO2; visible/Ag-TiO2; dark/Ag-TiO2; UV (all 100%) > UV/TiO2 (99%) > visib...

  15. Improvement of corrosion resistance of AZ31 Mg alloy by anodizing with co-precipitation of cerium oxide

    Institute of Scientific and Technical Information of China (English)

    Salah Abdelghany SALMAN; Ryoichi ICHINO; Masazumi OKIDO

    2009-01-01

    Anodizing of AZ31 Mg alloy in NaOH solution by co-precipitation of cerium oxide was investigated. The chemical composition and phase structure of the coating film were determined via optical microscopy, SEM and XRD. The corrosion properties of the anodic film were characterized by using potentiodynamic polarization curves in 17 mmol/L NaCl and 0.1 mol/L Na2SO4 solution at 298 K. The corrosion resistance of AZ31 magnesium alloy is significantly improved by adding cerium oxide to alkaline solution. In addition, the surface properties are enhanced and the film contains no crack.

  16. Effects of morphology on the structural and photoluminescence properties of co-precipitation derived GdVO4:Dy3+

    Science.gov (United States)

    Kumari, Puja; Manam, J.

    2016-10-01

    Herein, Dy3+ doped GdVO4 samples with various morphologies were prepared by the co-precipitation method at low temperature, and the effects of different morphologies on the structural and optical behaviors have been reported. The obtained samples were stabilized to the stable tetragonal structure. The IR and FESEM study were carried out to see the vibrational bonds position and surface morphology. At present PL, PLE, diffuse reflectance and decay curves have been discussed in detail. The morphology dependent photoluminescence studies were resulted to a suitable sample for the lighting and display applications.

  17. A comparison of facemask and respirator filtration test methods.

    Science.gov (United States)

    Rengasamy, Samy; Shaffer, Ronald; Williams, Brandon; Smit, Sarah

    2017-02-01

    NIOSH published a Federal Register Notice to explore the possibility of incorporating FDA required filtration tests for surgical masks (SMs) in the 42 CFR Part 84 respirator certification process. There have been no published studies comparing the filtration efficiency test methods used for NIOSH certification of N95 filtering facepiece respirators (N95 FFRs) with those used by the FDA for clearance of SMs. To address this issue, filtration efficiencies of "N95 FFRs" including six N95 FFR models and three surgical N95 FFR models, and three SM models were measured using the NIOSH NaCl aerosol test method, and FDA required particulate filtration efficiency (PFE) and bacterial filtration efficiency (BFE) methods, and viral filtration efficiency (VFE) method. Five samples of each model were tested using each method. Both PFE and BFE tests were done using unneutralized particles as per FDA guidance document. PFE was measured using 0.1 µm size polystyrene latex particles and BFE with ∼3.0 µm size particles containing Staphylococcus aureus bacteria. VFE was obtained using ∼3.0 µm size particles containing phiX 174 as the challenge virus and Escherichia coli as the host. Results showed that the efficiencies measured by the NIOSH NaCl method for "N95 FFRs" were from 98.15-99.68% compared to 99.74-99.99% for PFE, 99.62-99.9% for BFE, and 99.8-99.9% for VFE methods. Efficiencies by the NIOSH NaCl method were significantly (p = PFE, BFE, and VFE methods produced no significant difference. The above results show that the NIOSH NaCl method is relatively conservative and is able to identify poorly performing filtration devices. The higher efficiencies obtained using PFE, BFE and VFE methods show that adding these supplemental particle penetration methods will not improve respirator certification.

  18. Synthesis of mesoporous TiO(2-x)N(x) spheres by template free homogeneous co-precipitation method and their photo-catalytic activity under visible light illumination.

    Science.gov (United States)

    Parida, K M; Naik, Brundabana

    2009-05-01

    The article presents preparation, characterization and catalytic activity evaluation of an efficient nitrogen doped mesoporous titania sphere photo-catalyst for degradation of methylene blue (MB) and methyl orange (MO) under visible light illumination. Nitrogen doped titania was prepared by soft chemical route i.e. template free, slow and controlled homogeneous co-precipitation from titanium oxysulfate sulfuric acid complex hydrate, urea, ethanol and water. The molar composition of TiOSO(4) to urea was varied to prepare different atomic % nitrogen doped titania. Mesoporous anatase TiO(2-x)N(x) spheres with average crystallite size of 10 nm and formation of titanium oxynitride center were confirmed from HRTEM, XRD and XPS study. UV-vis DRS showed a strong absorption in the range of 400-500 nm which supports its use in visible spectrum of light. Nitrogen adsorption-desorption study supports the porous nature of the doped material. All the TiO(2-x)N(x) samples showed higher photo-catalytic activity than Degussa P(25) and undoped mesoporous titania. Sample containing around one atomic % nitrogen showed highest activity among the TiO(2-x)N(x) samples.

  19. Synthesis and characterization of a novel Mg–Al hydrotalcite-loaded kaolin clay and its adsorption properties for phosphate in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Lin, E-mail: denglinlyn@126.com; Shi, Zhou, E-mail: 369329062@qq.com

    2015-07-15

    Highlights: • Kaolin clay was coalesced with Mg–Al hydrotalcite to form composite adsorbent (MKC). • MKC was synthesized through modified co-precipitation method. • MKC gave high adsorption of phosphate over a wide pH range of 2.5–9.5. • MKC is an economical and environmentally friendly adsorbent for phosphate removal and recycling. - Abstract: The mesoporous modified kaolin clay (MKC) was synthesized by loading Mg–Al hydrotalcite onto kaolin clay through coprecipitation method and applied for adsorption of phosphate from aqueous solution. Several techniques, including Brunauer–Emmett–Teller (BET), thermal analysis (TG–DTA), and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the adsorbents. The effects of adsorbent dosage, solution pH, initial phosphate concentration, contact time, temperature, and coexistent anions on phosphate adsorption have been investigated. MKC exhibited a strong uptake affinity to phosphate in a wide pH range of 2.5–9.5, with the maximum adsorptive removal of 98.03%, at adsorbent dosage of 0.2 g/50 mL, pH 7.5, and initial phosphate concentration 25 mg L{sup −1}. The adsorption kinetics followed the pseudo-second-order kinetic model. The Langmuir isothermal model well described the adsorption isotherm data, showing a maximum adsorption capacity for phosphate up to 11.92 mg g{sup −1} at 298 K. The obtained thermodynamic parameters revealed that the adsorption of phosphate onto MKC was an exothermic and spontaneous process. Coexistent chloride, nitrate, and sulfate ions displayed an adverse effect on phosphate adsorption following the order of SO{sub 4}{sup 2−} > NO{sub 3}{sup −} > Cl{sup −}. A mechanism of adsorption that involved (i) electrostatic attraction of hydroxyl groups of the adsorbent with negatively charged phosphate ions, and (ii) anion exchange of NO{sub 3}{sup −} ions that were associated with the surface or interlayer of the adsorbent with anionic phosphate ions in

  20. Cd adsorption onto bacterial surfaces: A universal adsorption edge?

    Science.gov (United States)

    Yee, Nathan; Fein, Jeremy

    2001-07-01

    In this study, we measure the thermodynamic stability constants for proton and Cd binding onto the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the Gram-positive bacteria Bacillus megaturium, Streptococcus faecalis, Staphylococcus aureus, Sporosarcina ureae, and Bacillus cereus. Potentiometric titrations and Cd-bacteria adsorption experiments yield average values for the carboxyl site pK a, site concentration, and log stability constant for the bacterial surface Cd-carboxyl complex of 5.0, 2.0 × 10 -3 mol/g and 4.0 respectively. Our results indicate that a wide range of bacterial species exhibit nearly identical Cd adsorption behavior as a function of pH. We propose that metal-bacteria adsorption is not dependent on the bacterial species involved, and we develop a generalized adsorption model which may greatly simplify the task of quantifying the effects of bacterial adsorption on dissolved mass transport in realistic geologic systems.

  1. Synthesis of β-Cyclodextrin-Based Electrospun Nanofiber Membranes for Highly Efficient Adsorption and Separation of Methylene Blue.

    Science.gov (United States)

    Zhao, Rui; Wang, Yong; Li, Xiang; Sun, Bolun; Wang, Ce

    2015-12-09

    Water-insoluble β-cyclodextrin-based fibers were synthesized by electrospinining followed by thermal cross-linking. The fibers were characterized by field-emission scanning electron microscopic (FE-SEM) and Fourier transformed infrared spectrometer (FT-IR). The highly insoluble fraction obtained from different pH values (3-11) indicates successful cross-linking reactions and their usability in aqueous solution. After the cross-linking reaction, the fibers' tensile strength increases significantly and the BET surface area is 19.49 m(2)/g. The cross-linked fibers exhibited high adsorption capacity for cationic dye methylene blue (MB) with good recyclability. The adsorption performance can be fitted well with pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacity is 826.45 mg/g according to Langmuir fitting. Due to electrostatic repulsion, the fibers show weak adsorption toward negatively charged anionic dye methyl orange (MO). On the basis of the selective adsorption, the fiber membrane can separate the MB/MO mixture solution by dynamic filtration at a high flow rate of 150 mL/min. The fibers can maintain good fibrous morphology and high separation efficiency even after five filtration-regeneration cycles. The obtained results suggested potential applications of β-cyclodextrin-based electrospun fibers in the dye wastewater treatment field.

  2. Synthesis of magnetic biocomposite for efficient adsorption of azo dye from aqueous solution.

    Science.gov (United States)

    Sivashankar, R; Sathya, A B; Krishnakumar, Uma; Sivasubramanian, V

    2015-11-01

    A novel magnetic biocomposite was synthesized using metal chlorides and aquatic macrophytes by co-precipitation method. The resulting product, magnetic biocomposite was characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). The adsorption performance of the magnetic biocomposite was tested with removal of Metanil Yellow dye from aqueous solution. The effect of influencing parameters such as initial dye concentration, solution pH and agitation were investigated. The equilibrium isotherm was well described by the Langmuir model with the with maximum adsorption capacity of 90.91mg/g. Adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the magnetic biocomposite could efficiently adsorb the azo dyes from aqueous solution, and the spent adsorbents could be recovered completely by magnetic separation process. Therefore, the prepared magnetic biocomposite could thus be used as promising adsorbent for the removal of azo dyes from polluted water.

  3. Quality-by-design: an integrated process analytical technology approach to determine the nucleation and growth mechanisms during a dynamic pharmaceutical coprecipitation process.

    Science.gov (United States)

    Wu, Huiquan; Khan, Mansoor A

    2011-05-01

    The objective of this study was to demonstrate the feasibility of using an integrated process analytical technology (PAT) approach to determine nucleation and growth mechanisms of a dynamic naproxen (drug)-Eudragit L100 (polymer) coprecipitation process. The influence of several thermodynamically important formulation and process variables (drug/polymer ratio, alcohol, and water usages) on coprecipitation process characteristics was investigated via real-time in situ focused beam reflectance measurement (FBRM) monitoring and near real-time particle vision microscopy measurement. The final products were characterized by near-infrared (NIR) spectroscopy and NIR chemical imaging microscopy. The coprecipitation nucleation induction time (t(ind) ) was measured by both FBRM trend statistics and process trajectory method, respectively. Furthermore, nucleation kinetics was evaluated based on t(ind) measurement and corresponding supersaturation ratio (S) estimated. It was found that plots of ln(t(ind) ) versus (ln(2) S)(-1) consist of two linear segments and are consistent with classical primary nucleation mechanisms. Apparently, the coprecipitation process is governed by heterogeneous primary nucleation mechanism at low S (14 ≤ S ≤ 503) and by homogeneous primary nucleation mechanism at high S (1216 ≤ S ≤ 3649). Off-line characterizations collectively supported this statement. Therefore, it demonstrated that integration real-time PAT process monitoring with first-principles modeling and off-line product characterization could enhance understanding to coprecipitation process dynamics and nucleation/growth mechanisms, which is impossible via off-line techniques alone.

  4. Synthesis of layered double hydroxides containing Mg2+, Zn2+, Ca2+ and Al3+ layer cations by co-precipitation methods-A review

    Science.gov (United States)

    Theiss, Frederick L.; Ayoko, Godwin A.; Frost, Ray L.

    2016-10-01

    Co-precipitation is a common method for the preparation of layered double hydroxides (LDHs) and related materials. This review article is aimed at providing newcomers to the field with some examples of the types of co-precipitation reactions that have been reported previously and to briefly investigate some of the properties of the products of these reactions. Due to the sheer volume of literature on the subject, the authors have had to limit this article to the synthesis of Mg/Al, Zn/Al and Ca/Al LDHs by co-precipitation and directly related methods. LDHs have been synthesised from various reagents including metal salts, oxides and hydroxides. Co-precipitation is also useful for the direct synthesis of LDHs with a wide range of interlayer anions and various bases have been successfully employed to prepare LDHs. Examples of other synthesis techniques including the urea method, hydrothermal synthesis and various mechanochemical methods that are undoubtedly related to co-precipitation have also been included in this review. The effect of post synthesis hydrothermal has also been summarised.

  5. Silver nanoparticle-doped zirconia capillaries for enhanced bacterial filtration.

    Science.gov (United States)

    Wehling, Julia; Köser, Jan; Lindner, Patrick; Lüder, Christian; Beutel, Sascha; Kroll, Stephen; Rezwan, Kurosch

    2015-03-01

    Membrane clogging and biofilm formation are the most serious problems during water filtration. Silver nanoparticle (Agnano) coatings on filtration membranes can prevent bacterial adhesion and the initiation of biofilm formation. In this study, Agnano are immobilized via direct reduction on porous zirconia capillary membranes to generate a nanocomposite material combining the advantages of ceramics being chemically, thermally and mechanically stable with nanosilver, an efficient broadband bactericide for water decontamination. The filtration of bacterial suspensions of the fecal contaminant Escherichia coli reveals highly efficient bacterial retention capacities of the capillaries of 8 log reduction values, fulfilling the requirements on safe drinking water according to the U.S. Environmental Protection Agency. Maximum bacterial loading capacities of the capillary membranes are determined to be 3×10(9)bacterialcells/750mm(2) capillary surface until back flushing is recommendable. The immobilized Agnano remain accessible and exhibit strong bactericidal properties by killing retained bacteria up to maximum bacterial loads of 6×10(8)bacterialcells/750mm(2) capillary surface and the regenerated membranes regain filtration efficiencies of 95-100%. Silver release is moderate as only 0.8% of the initial silver loading is leached during a three-day filtration experiment leading to average silver contaminant levels of 100μg/L.

  6. Spontaneous water filtration of bio-inspired membrane

    Science.gov (United States)

    Kim, Kiwoong; Kim, Hyejeong; Lee, Sang Joon

    2016-11-01

    Water is one of the most important elements for plants, because it is essential for various metabolic activities. Thus, water management systems of vascular plants, such as water collection and water filtration have been optimized through a long history. In this view point, bio-inspired technologies can be developed by mimicking the nature's strategies for the survival of the fittest. However, most of the underlying biophysical features of the optimized water management systems remain unsolved In this study, the biophysical characteristics of water filtration phenomena in the roots of mangrove are experimentally investigated. To understand water-filtration features of the mangrove, the morphological structures of its roots are analyzed. The electrokinetic properties of the root surface are also examined. Based on the quantitatively analyzed information, filtration of sodium ions in the roots are visualized. Motivated by this mechanism, spontaneous desalination mechanism in the root of mangrove is proposed by combining the electrokinetics and hydrodynamic transportation of ions. This study would be helpful for understanding the water-filtration mechanism of the roots of mangrove and developing a new bio-inspired desalination technology. This research was financially supported by the National Research Foundation (NRF) of Korea (Contract Grant Number: 2008-0061991).

  7. Impact of Acidification on Pollutants Fate and Soil Filtration Function

    Directory of Open Access Journals (Sweden)

    Jarmila Makovniková

    2014-12-01

    Full Text Available The objective of this paper was to investigate the effects of simulated acid load on the fate of inorganic pollutants (Cd, Pb, soil sorption potential, soil filtration func-tion. We made use of a short-term acidification pot experiment with grown plant of spring barley cultivated at 4 different soil types (Fluvisol, Cambisol, Stagnosol, Podzol. The potential of soil filtration was evaluated according to the Eq.: [Soil filtration function]=[Potential of soil sorbents]+[Potential of total content of inor-ganic pollutants]. Potential of soil sorbents (PSS is defined by qualitative (pH, or-ganic matter quality - A400/600 and quantitative factors (carbon content-Cox, humus layer thickness-H according to the Eq.:[PSS]=F(pH+F(A465/665+F(Cox*F(H. Acid load significantly influenced soil sorption potential and thus affected increase in Cd and Pb mobility what was reflected in their transfer into the plants. Results of soil filtration function showed significant change of filtration function in Cambisol.

  8. Water quality and treatment of river bank filtrate

    Directory of Open Access Journals (Sweden)

    W. W. J. M. de Vet

    2010-06-01

    Full Text Available In drinking water production, river bank filtration has the advantages of dampening peak concentrations of many dissolved components, substantially removing many micropollutants and removing, virtually completely, the pathogens and suspended solids. The production aquifer is not only fed by the river bank infiltrate but also by water percolating through covering layers. In the polder areas, these top layers consist of peat and deposits from river sediments and sea intrusions.

    This paper discusses the origin and fate of macro components in river bank filtrate, based on extensive full-scale measurements in well fields and treatment systems of the Drinking Water Company Oasen in the Netherlands. First, it clarifies and illustrates redox reactions and the mixing of river bank filtrate and PW as the dominant processes determining the raw water quality for drinking water production. Next, full-scale results are elaborated on to evaluate trickling filtration as an efficient and proven one-step process to remove methane, iron, ammonium and manganese. The interaction of methane and manganese removal with nitrification in these systems is further analyzed. Methane is mostly stripped during trickling filtration and its removal hardly interferes with nitrification. Under specific conditions, microbial manganese removal may play a dominant role.

  9. Enhancement of fine particle filtration with efficient humidification☆

    Institute of Scientific and Technical Information of China (English)

    Yumei Zhang; Weidong Zhang; Zhengyu Yang; Junteng Liu; Fushen Yang; Ning Li; Le Du⁎

    2016-01-01

    Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes, pressure drop of compact dust cake causes problems in efficiency and economy, which has received increasing at-tention and stil remains chal enging. In this study, we developed a novel technique to intensify the filtration of fine particles with efficient humidification. Two strategies for humidification, including ultrasonic atomization and steam humidification (control ing of ambient humidity), were employed and proved to be both effective. The re-generation frequency of the filter could be reduced by 55%with ultrasonic atomization, while steam humidification could lead to a 78%reduction in regeneration frequency. The effect of operating conditions on pressure drop and the mass loading during filtration were investigated. The dust cake showed a loose and porous structure with an opti-mized droplet-to-particle ratio. With the ratio of 1.53 and 0.0282, the maximum mass loading was 552 g·m−2 upon the ultrasonic atomization and 720 g·m−2 upon the steam humidification. The results show that humidification could slow down the increase of pressure drop during filtration and improve the efficiency of process.

  10. Effect of membrane filtration artifacts on dissolved trace element concentrations

    Science.gov (United States)

    Horowitz, Arthur J.; Elrick, Kent A.; Colberg, Mark R.

    1992-01-01

    Among environment scientists, the current and almost universally accepted definition of dissolved constituents is an operational one; only those materials which pass through a 0.45-??m membrane filter are considered to be dissolved. Detailed laboratory and field studies on Fe and Al indicate that a number of factors associated with filtration, other than just pore size, can substantially alter 'dissolved' trace element concentrations; these include: filter type, filter diameter, filtration method, volume of sample processed, suspended sediment concentration, suspended sediment grain-size distribution, concentration of colloids and colloidally associated trace elements and concentration of organic matter. As such, reported filtered-water concentrations employing the same pore size filter may not be equal. Filtration artifacts may lead to the production of chemical data that indicate seasonal or annual 'dissolved' chemical trends which do not reflect actual environmental conditions. Further, the development of worldwide averages for various dissolved chemical constituents, the quantification of geochemical cycles, and the determination of short- or long-term environmental chemical trends may be subject to substantial errors, due to filtration artifacts, when data from the same or multiple sources are combined. Finally, filtration effects could have a substantial impact on various regulatory requirements.

  11. Transforming growth factor-beta and the glomerular filtration barrier

    Directory of Open Access Journals (Sweden)

    Ayesha Ghayur

    2013-03-01

    Full Text Available The increasing burden of chronic kidney disease worldwide and recent advancements in the understanding of pathologic events leading to kidney injury have opened up new potential avenues for therapies to further diminish progression of kidney disease by targeting the glomerular filtration barrier and reducing proteinuria. The glomerular filtration barrier is affected by many different metabolic and immune-mediated injuries. Glomerular endothelial cells, the glomerular basement membrane, and podocytes—the three components of the filtration barrier—work together to prevent the loss of protein and at the same time allow passage of water and smaller molecules. Damage to any of the components of the filtration barrier can initiate proteinuria and renal fibrosis. Transforming growth factor-beta (TGF-β is a pleiotropic cytokine strongly associated with the fibrogenic response. It has a known role in tubulointerstitial fibrosis. In this review we will highlight what is known about TGF-β and how it interacts with the components of glomerular filtration barrier and causes loss of function and proteinuria.

  12. Effect of Nanofibers on Spore Penetration and Lunar Dust Filtration

    Directory of Open Access Journals (Sweden)

    Phil Gibson, Ph.D.

    2008-06-01

    Full Text Available The results of two separate studies on biological spore penetration and simulated lunar dust filtration illustrate the use of nanofibers in some nonstandard filtration applications (nanofibers are generally defined as having diameters of less than a micron. In the first study, a variety of microporous liners containing microfibers and nanofibers were combined with cotton-based fabrics in order to filter aerosolized spores. The aerosol penetration resistance of the nanofiber-lined fabrics was measured, and some analysis was conducted of where the particles are captured within the fabric layers. Testing was conducted with aerosolized living spores, in order to evaluate the efficacy of various fabric treatments on spore viability within the fabric layers after exposure. Reported are the results of studies on fabrics with and without a removable electrospun nanofiber liner, and the fate of the spores within the fabric layers. In the second study, non-instrumented filtration testing using simulated lunar dust determined the comparative filtration efficiency of various nonwoven filtration media. Nanofiber witness media, combined with scanning electron microscope images, showed that an electrospun nonwoven filter layer effectively filtered out all the large and fine particles of the simulated lunar dust.

  13. Technology Review of Modern Gas Turbine Inlet Filtration Systems

    Directory of Open Access Journals (Sweden)

    Melissa Wilcox

    2012-01-01

    Full Text Available An inlet air filtration system is essential for the successful operation of a gas turbine. The filtration system protects the gas turbine from harmful debris in the ambient air, which can lead to issues such as FOD, erosion, fouling, and corrosion. These issues if not addressed will result in a shorter operational life and reduced performance of the gas turbine. Modern day filtration systems are comprised of multiple filtration stages. Each stage is selected based on the local operating environment and the performance goals for the gas turbine. Selection of these systems can be a challenging task. This paper provides a review of the considerations for selecting an inlet filtration system by covering (1 the characteristics of filters and filter systems, (2 a review of the many types of filters, (3 a detailed look at the different environments where the gas turbine can operate, (4 a process for evaluating the site where the gas turbine will be or is installed, and (5 a method to compare various filter system options with life cycle cost analysis.

  14. Oviposition Attractancy of Bacterial Culture Filtrates: response of Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    S Poonam

    2002-04-01

    Full Text Available Oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. In the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of Culex quinquefasciatus. When their oviposition active indices (OAI were studied, the culture filtrates of Bacillus cereus and Pseudomonas fluorescens exhibited oviposition attractancy (OAI = >0.3 at 100 ppm and the OAI were respectively 0.70 and 0.47. Culture filtrates of B. thuringiensis var. israelensis (wild type, B. t. var. israelensis (mutant and B. sphaericus showed attractancy at 2000 ppm with OAI of respectively 0.71, 0.59 and 0.68. However, the OAI of B. megaterium as well as Azospirillum brasilense was 0.13 (at 2000 ppm, which was less than 0.3 required to be considered them as attractants. When the oviposition attractancy of the bacterial culture filtrates were compared with that of a known oviposition attractant, p-cresol (at 10 ppm, the culture filtrates of B. t. var. israelensis (wild type and B. cereus were found to be more active than p-cresol, respectively with 64.2 and 54.3% oviposition.

  15. Pharmacologic Atrial Natriuretic Peptide Reduces Human Leg Capillary Filtration

    Science.gov (United States)

    Watenpaugh, Donald E.; Vissing, Susanne F.; Lane, Lynda D.; Buckey, Jay C.; Firth, Brian G.; Erdman, William; Hargens, Alan R.; Blomqvist, C. Gunnar

    1995-01-01

    Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethys-mography of supine health male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n equals 6) and during placebo infusion (n equals 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma (ANP) from 30 plus or minus 4 to 2,568 plus or minus 595 pmol/L. Systemic hemoconcentration occurred during ANP infusion; mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3 percent respectively, relative to pre-infusion baseline values (p is less than 0.05). Mean calf filtration, however was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20 percent with ANP infusion, wheras blood pressure was unchanged. Calf conductance (blood flow/arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, phamacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchic sites or both, while having the opposite effect in the leg.

  16. Synthesis, characterization and application of Lagerstroemia speciosa embedded magnetic nanoparticle for Cr(VI) adsorption from aqueous solution.

    Science.gov (United States)

    Srivastava, Shalini; Agrawal, Shashi Bhushan; Mondal, Monoj Kumar

    2017-05-01

    Lagerstroemia speciosa bark (LB) embedded magnetic nanoparticles were prepared by co-precipitation of Fe(2+) and Fe(3+) salt solution with ammonia and LB for Cr(VI) removal from aqueous solution. The native LB, magnetic nanoparticle (MNP), L. speciosa embedded magnetic nanoparticle (MNPLB) and Cr(VI) adsorbed MNPLB particles were characterized by SEM-EDX, TEM, BET-surface area, FT-IR, XRD and TGA methods. TEM analysis confirmed nearly spherical shape of MNP with an average diameter of 8.76nm and the surface modification did not result in the phase change of MNP as established by XRD analysis, while led to the formation of secondary particles of MNPLB with diameter of 18.54nm. Characterization results revealed covalent binding between the hydroxyl group of MNP and carboxyl group of LB particles and further confirmed its physico-chemical nature favorable for Cr(VI) adsorption. The Cr(VI) adsorption on to MNPLB particle as an adsorbent was tested under different contact time, initial Cr(VI) concentration, adsorbent dose, initial pH, temperature and agitation speed. The results of the equilibrium and kinetics of adsorption were well described by Langmuir isotherm and pseudo-second-order model, respectively. The thermodynamic parameters suggest spontaneous and endothermic nature of Cr(VI) adsorption onto MNPLB. The maximum adsorption capacity for MNPLB was calculated to be 434.78mg/g and these particles even after Cr(VI) adsorption were collected effortlessly from the aqueous solution by a magnet. The desorption of Cr(VI)-adsorbed MNPLB was found to be more than 93.72% with spent MNPLB depicting eleven successive adsorption-desorption cycles. Copyright © 2016. Published by Elsevier B.V.

  17. Synthesis and characterization of La(Cr,Fe,Mn)O{sub 3} nanoparticles obtained by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, F.A., E-mail: fernandafabianro@gmail.com [Universidade Federal de Sergipe, Campus Prof. Aluísio Campos, Departamento de Física, 49100-000 São Cristóvão, SE (Brazil); Pedra, P.P.; Filho, J.L.S. [Universidade Federal de Sergipe, Campus Prof. Aluísio Campos, Departamento de Física, 49100-000 São Cristóvão, SE (Brazil); Duque, J.G.S.; Meneses, C.T. [Universidade Federal de Sergipe, Campus Prof. Alberto Carvalho, Departamento de Física, 49500-000 Itabaiana, SE (Brazil)

    2015-04-01

    Magnetic and structural properties have been investigated in La(Cr,Fe,Mn)O{sub 3} nanoparticles obtained by co-precipitation method. The X-ray diffraction measurements allied to Rietveld method confirm the formation of LaCrO{sub 3}, LaFeO{sub 3} and LaMnO{sub 3} nanoparticles with crystal structure orthorhombic (Pbnm), orthorhombic (Pnma) and rhombohedral (R-3c), respectively. We also verified an decreasing in the average crystallite size from 73 to 26 nm, depending of the transition metal. The magnetic measurements reveal an antiferromagnetic behavior for the LaCrO{sub 3} sample with T{sub N}~289 K, and a weak ferromagnetic ordering for the LaMnO{sub 3} sample with T{sub c}~200 K. - Highlights: • La(Cr,Fe,Mn)O{sub 3} nanoparticles were synthesized by coprecipitation method. • XRD results confirm the formation single phase in the compounds studied. • Magnetic property in the La(Fe,Cr,Mn)O{sub 3} nanoparticles dependent on the TM. • La(Cr,Fe)O{sub 3} nanoparticles presented behavior antiferromagnetic and LaMnO{sub 3} ferromagnetic.

  18. Oxidation of aqueous EDTA and associated organics and coprecipitation of inorganics by ambient iron-mediated aeration.

    Science.gov (United States)

    Englehardt, James D; Meeroff, Daniel E; Echegoyen, Luis; Deng, Yang; Raymo, Françisco M; Shibata, Tomoyuki

    2007-01-01

    Cationic metal and radionuclide contaminants can be extracted from soils to groundwater with sequestering agents such as EDTA. However, EDTA must then be removed fromthe groundwater, by advanced oxidation or specialized biological treatment. In this work, aqueous individual metal-EDTA solutions were aerated with steel wool for 25 h, at ambient pH, temperature, and pressure. Removal of approximately 99% of EDTA (0.09-1.78 mM); glyoxylic acid (0.153 mM); chelated Cd2+ (0.94 and 0.0952 mM), Pb2+ (0.0502 mM), and Hg2+ (0.0419 mM); and free chromate and vanadate was shown. EDTA was oxidized to glyoxylic acid and formaldehyde, and metals/metalloids were coprecipitated together with iron oxyhydroxide floc. Free arsenite and arsenate were each removed at 99.97%. Free Sr2+, and chelated Ni2+ were removed at 92% and 63%, respectively. Similar removals were obtained from mixtures, including 99.996+/-0.004% removal of total arsenic (95% confidence). Traces of iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetriacetic acid were detected after 25 h. Results are consistent with first-order, solution-phase oxidation of EDTA and glyoxylic acid by ferryl ion and H202, respectively, with inhibition due to sludge accumulation, and equilibrium metal coprecipitation. This ambient process, to our knowledge previously unknown, agrees with recently reported findings and shows promise for remediation of metals, metalloids, and radionuclides in wastewater, soil, and sediment.

  19. Phase pure synthesis of BiFeO{sub 3} nanopowders using diverse precursor via co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Shami, M. Yasin, E-mail: m_yasin_shami@yahoo.com [Applied Thermal Physics Laboratory, Department of Physics, COMSATS Institute of Information Technology, Park Road, Islamabad 44000 (Pakistan); Awan, M.S. [Center for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Park Road, Islamabad 44000 (Pakistan); Anis-ur-Rehman, M. [Applied Thermal Physics Laboratory, Department of Physics, COMSATS Institute of Information Technology, Park Road, Islamabad 44000 (Pakistan)

    2011-10-13

    Highlights: > Synthesized phase pure BiFeO{sub 3} using diverse precursor by co-precipitation method. > Optimized synthesis and processing parameters. > Thermal behavior, structure and microstructure were analyzed. > Resistivity vs temperature and dielectric constant vs frequency were measured. > Multiferroicity at room temperature was confirmed by M-H and P-E loops. - Abstract: Amorphous powder of BiFeO{sub 3} (BFO) was synthesized at low-temperature (80 deg. C) by co-precipitation method. Optimal synthesis conditions for phase pure BFO were obtained. Powders were calcined in the temperature range from 400 to 600 deg. C for 1 h. Iso-statically pressed powder was sintered at 500 deg. C for 2 h. Differential scanning calorimetric thermo-gram guided for phase transition, crystallization and melting temperatures. X-ray diffraction confirmed the amorphous nature of as synthesized powder and phase formation of calcined powders. Calcination at temperature {>=}400 deg. C resulted in nano crystalline powders with perovskite structure. Average crystallite size increased with the increase in calcination temperature. Scanning electron microscopic studies revealed dense granular microstructure of the sintered samples. The sintered samples exhibited high dc resistivity at room temperature which decreased with the increase in temperature. Dielectric constant, dielectric loss tangent and ac conductivity measurements were carried out in the frequency range (10 Hz to 2 MHz). The samples responded weak electric and magnetic polarization at room temperature with unsaturated and hysteresis free loops, respectively.

  20. Characterization of γ- Al{sub 2}O{sub 3} nanopowders synthesized by Co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Jbara, Ahmed S., E-mail: ahmedsbhe@yahoo.com [Center for Sustainable Nanomaterials, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Physics Department, Science College, Al-Muthanna University, Samawah - 66001 (Iraq); Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Othaman, Zulkafli [Center for Sustainable Nanomaterials, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Ati, Ali A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Saeed, M.A., E-mail: moalsd@gmail.com [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Division of Science and Technology, University of Education, Township, Lahore - 54770 (Pakistan)

    2017-02-15

    Co-precipitation technique has been used to synthesize gamma-Al{sub 2}O{sub 3} (γ-Al{sub 2}O{sub 3}) nanopowders under annealing temperature effect. The crystalline phase and purity for the prepared powder were characterized by different spectroscopy techniques. XRD analysis confirms the gamma phase of alumina nanopowders with particle diameter ranging from 6 to 24 nm, which confirms the quantum dots formation, which is also supported by the BET measurement. The surface area of the prepared nanopowders is in the range of 109–367 m{sup 2}/g. Morphology analysis indicates that γ-Al{sub 2}O{sub 3} nanopowders are consisted of grains almost spherical in shape. Some agglomeration of nanoparticles occurs, which become more regular hexagonal shaped with the increasing annealing temperature. The small nanoparticles size and the high surface area from a simple procedure for preparing γ-Al{sub 2}O{sub 3} may make it more suitable for use as an adsorbent for malachite green. - Highlights: • Co-precipitation technique is used to synthesize gamma- Al{sub 2}O{sub 3} nanopowders. • Pure gamma- Al{sub 2}O{sub 3} phase was obtained having maximum nanoparticle size is 24 nm. • The quantum dots were formed inside powder. • High surface area of nanopowders at the low annealing temperature. • Increasing annealing temperature causes the hexagonal agglomeration shape.

  1. Properties of Co2FeAl Heusler Alloy Nano-particles Synthesized by Coprecipitation and Thermal Deoxidization Method

    Institute of Scientific and Technical Information of China (English)

    J.H.Du; Y.L.Zuo; Z.Wang; J.H.Ma; L.Xi

    2013-01-01

    Co2FeAl nanoparticles were synthesized by reducing the coprecipitated precursor of CoCl2·6H2O,Fe(NO3)3·9H2O and Al2(SO4)3·18H2O under H2 atmosphere with various annealing temperatures and durations.X-ray diffraction and transmission electron microscopy were used to characterize the crystal structure and microstructure of Co2FeAl particles,respectively.The investigation indicates that the crystal structure of Co2FeAl particles tends to be B2 structure,in which atoms are partially ordered.The saturation magnetization and hyperfine field of Co2FeAl particles,which were measured under a vibrating sample magnetometer and a 57Fe M(o)ssbauer spectroscope,are consistent with those of the bulk sample and thin films.Furthermore,the higher annealing temperature and the longer annealing time,the better crystallinity of Co2FeAl and more ordered arrangement of atoms will be.It turned out that the coprecipitation thermal deoxidization method could be an easy and high efficient way to obtain the half-metallic Co2FeAl nanoparticles.

  2. Investigation of sintered cobalt-zinc ferrite synthesized by coprecipitation at different temperatures: a relation between microstructure and hysteresis curves

    Directory of Open Access Journals (Sweden)

    Ana Maria Rangel de Figueiredo Teixeira

    2006-09-01

    Full Text Available The magnetic properties of sintered samples of cobalt-zinc ferrites produced from the corresponding coprecipitate were calculated based on hysteresis curves (Hc. The Hc values confirmed that soft ferrites were obtained by the procedure. A possible relation between the magnetic hysteresis curves and the microstructure of the sintered samples was investigated. X ray diffraction, thermal analysis and scanning electron microscopy were used to characterize the microstructure and the phases present in the sintered ceramic pieces, as well as those of their coprecipitated tri-metallic hydroxide precursor powders. It was found that sintering of Co0.5Zn0.5Fe2O4 at 1400 °C led to "honeycombing" of the ferrite grains and that there was no single phase in the microstructure of a sample sintered at 1400 °C. Thus, a more complete study was made of the behavior of the microstructure at lower sintering temperatures, i.e., in the 1100-1350 °C range.

  3. Complexation-Coprecipitation Synthesis and Characterization of Neodymium and Antimony Doped SnO2 Conductive Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nd and Sb doped SnO2 conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb2O3 and Nd2O3 as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC/DTG, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles was 0.12 Ω·cm. TG/DSC/DTG curves show that the precursors lose weight completely before 750 ℃. FTIR spectrum shows that the vibration peaks are wide peaks in 731~617 cm-1, and the Nd and Sb doped SnO2 conductive nanoparticles have intense absorption in 4000~2000 cm-1. Nd and Sb doped SnO2 have a structure of tetragonal rutile, and complex doping is achieved well by complexation-coprecipitation method and is recognized as replacement doping or caulking doping. TME shows that the particles are weakly agglomerated, and the size of the particles calcined at 1000 ℃ ranges about 10 nm to 30 nm.

  4. Effect of Ferric Chloride on the Properties of Biological Sludge in Co-precipitation Phosphorus Removal Process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhibin; LI Yi; WEI Leilei; L(U) Yufeng; WANG Meng; GAO Baoyu

    2013-01-01

    This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the concentration of mixed liquid suspended solid (MLSS) was 2436 mg·L-1 and 2385 mg·L-1 in co-precipitation phosphorus removal process (CPR) and biological phosphorous removal process (BPR),respectively.The sludge reduction ratio for each process was 22.6% and 24.6% in aerobic digestion,and 27.6% and 29.9% in anaerobic digestion,respectively.Due to the addition of chemical to the end of aeration tank,the sludge content of CPR was slightly higher than that of BPR,but the sludge reduction rate for both processes had no distinct difference.The sludge volume index (SVI) and sludge specific resistance of BPR were 126 ml·g-1 and 11.7×1012 m·kg-1,respectively,while those of CPR were only 98 ml·g-1 and 7.1×1012 m·kg-1,indicating that CPR chemical could improve sludge settling and dewatering.

  5. Co-precipitation of tobramycin into biomimetically coated orthopedic fixation pins employing submicron-thin seed layers of hydroxyapatite.

    Science.gov (United States)

    Sörensen, Jan H; Lilja, Mirjam; Åstrand, Maria; Sörensen, Torben C; Procter, Philip; Strømme, Maria; Steckel, Hartwig

    2014-01-01

    The migration, loosening and cut-out of implants and nosocomial infections are current problems associated with implant surgery. New innovative strategies to overcome these issues are emphasized in today's research. The current work presents a novel strategy involving co-precipitation of tobramycin with biomimetic hydroxyapatite (HA) formation to produce implant coatings that control local drug delivery to prevent early bacterial colonization of the implant. A submicron- thin HA layer served as seed layer for the co-precipitation process and allowed for incorporation of tobramycin in the coating from a stock solution of antibiotic concentrations as high as 20 mg/ml. Concentrations from 0.5 to 20 mg/ml tobramycin and process temperatures of 37 °C and 60 °C were tested to assess the optimal parameters for a thin tobramycin- delivering HA coating on discs and orthopedic fixation pins. The morphology and thickness of the coating and the drug-release profile were evaluated via scanning electron microscopy and high performance liquid chromatography. The coatings delivered pharmaceutically relevant amounts of tobramycin over a period of 12 days. To the best of our knowledge, this is the longest release period ever observed for a fast-loaded biomimetic implant coating. The presented approach could form the foundation for development of combination device/antibiotic delivery vehicles tailored to meet well-defined clinical needs while combating infections and ensuring fast implant in-growth.

  6. Preparation and Characterization of Gd3Sc2Ga3O12 Polycrystalline Material by Co-Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Gd3Sc2Ga3O12 polycrystalline material for single crystal growth was prepared with Ga, Gd2O3 and Sc2O3 as starting materials and aqueous ammonia as the precipitator by co-precipitation method. The precursors sintered at various temperatures were characterized by infrared spectra (IR), X-ray diffractometry (XRD) and transmitted electron microscopy (TEM). The results showed that pure GSGG phase could be obtained at 900 ℃. The sintered powders were well-dispersed and less-aggregated in the sintered temperature range of 900~1000 ℃. XRD and TEM show that the polycrystalline particle sizes of the polycrystalline powders were about 20~50 nm. Compared with the method that Ga2O3, Gd2O3 and Sc2O3 were mixed directly and sintered to get polycrystalline materials, the synthesized temperature was lower and sintered time was shorter. Thus co-precipitation was a good method to synthesize GSGG polycrystalline material.

  7. Study of effect of planetary ball milling on ZnO nanopowder synthesized by co-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, K.P., E-mail: kiranshinde_phy@yahoo.co.in [Superconductivity Research Centre, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Pawar, R.C. [Department of Materials Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Sinha, B.B. [Nano Functional Materials Research Group, Department of Powder Materials, Korea Institute of Material Science, Changwon 641-831 (Korea, Republic of); Kim, H.S.; Oh, S.S. [Superconductivity Research Centre, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Chung, K.C. [Nano Functional Materials Research Group, Department of Powder Materials, Korea Institute of Material Science, Changwon 641-831 (Korea, Republic of)

    2014-12-25

    Highlights: • Synthesis of ZnO nanopowder by co-precipitation method. • Particle size reduction using planetary ball milling. • PL spectra shows shifting towards higher wavelength with decrease in intensity. • The bandgap energy (E{sub g}) of ZnO powders varied from 3.13 to 2.85 eV. - Abstract: Nanocrystalline ZnO powders have been synthesized by co-precipitation method and investigated planetary ball milling effects on structural and optical properties. These powders were characterized using X-ray diffraction, field emission scanning electronic microscope, Infrared spectrophotometer, UV–vis spectrophotometer and Photoluminescence. It was found that prepared ZnO powders have hexagonal close packed structure which was annealed at 500 °C for 30 min. The bandgap energy of ZnO powders varied from 3.13 to 2.85 eV. The room temperature PL spectra exhibits low intensity UV emission peak at 383 nm and green emission band around 520 nm shows shifting towards higher wavelength with decrease in intensity of peak with time of planetary ball milling. Hence, it was observed that planetary ball milling can be used to tailor the optoelectronic properties of ZnO nanostructures.

  8. Particle size and magnetic properties dependence on growth temperature for rapid mixed co-precipitated magnetite nanoparticles

    Science.gov (United States)

    Fang, Mei; Ström, Valter; Olsson, Richard T.; Belova, Lyubov; Rao, K. V.

    2012-04-01

    Magnetite nanoparticles have been prepared by co-precipitation using a custom-designed jet mixer to achieve rapid mixing (RM) of reactants in a timescale of milliseconds. The quick and stable nucleation obtained allows control of the particle size and size distribution via a more defined growth process. Nanoparticles of different sizes were prepared by controlling the processing temperature in the first few seconds post-mixing. The average size of the nanoparticles investigated using a Tecnai transmission electron microscope is found to increase with the temperature from 3.8 nm at 1 ± 1 °C to 10.9 nm for particles grown at 95 ± 1 °C. The temperature dependence of the size distribution follows the same trend and is explained in terms of Ostwald ripening of the magnetite nanoparticles during the co-precipitation of Fe2+ and Fe3+. The magnetic properties were studied by monitoring the blocking temperature via both DC and AC techniques. Strikingly, the obtained RM particles maintain the high magnetization (as high as ˜88 A m2 kg-1 at 500 kA m-1) while the coercivity is as low as ˜12 A m-1 with the expected temperature dependence. Besides, by adding a drop of tetramethylammonium hydroxide, aqueous ferrofluids with long term stability are obtained, suggesting their suitability for applications in ferrofluid technology and biomedicine.

  9. Evaluation of Three Chitin Metal Silicate Co-Precipitates as a Potential Multifunctional Single Excipient in Tablet Formulations

    Directory of Open Access Journals (Sweden)

    Rana Al-Shaikh Hamid

    2010-05-01

    Full Text Available The performance of the novel chitin metal silicate (CMS co-precipitates as a single multifunctional excipient in tablet formulation using direct compression and wet granulation methods is evaluated. The neutral, acidic, and basic drugs Spironolactone (SPL, ibuprofen (IBU and metronidazole (MET, respectively, were used as model drugs. Commercial Aldactone®, Fleximex® and Dumazole® tablets containing SPL, IBU and MET, respectively, and tablets made using Avicel® 200, were used in the study for comparison purposes. Tablets of acceptable crushing strength (>40 N were obtained using CMS. The friability values for all tablets were well below the maximum 1% USP tolerance limit. CMS produced superdisintegrating tablets (disintegration time < 1 min with the three model drugs. Regarding the dissolution rate, the sequence was as follow: CMS > Fleximex® > Avicel® 200, CMS > Avicel® 200 > Dumazole® and Aldactone® > Avicel® 200 > CMS for IBU, MET and SPL, respectively. Compressional properties of formulations were analyzed using density measurements and the compression Kawakita equation as assessment parameters. On the basis of DSC results, CMS co precipitates were found to be compatible with the tested drugs. Conclusively, the CMS co-precipitates have the potential to be used as filler, binder, and superdisintegrant, all-in-one, in the design of tablets by the direct compression as well as wet granulation methods.

  10. Effect of pH value on electromagnetic loss properties of Co-Zn ferrite prepared via coprecipitation method

    Science.gov (United States)

    Huang, Xiaogu; Zhang, Jing; Wang, Wei; Sang, Tianyi; Song, Bo; Zhu, Hongli; Rao, Weifeng; Wong, Chingping

    2016-05-01

    In this paper, the cobalt zinc ferrite was prepared by coprecipitation method at different pH conditions. The influence of pH values on the coprecipitation reaction was theoretically analyzed at first. The calculated results showed that the pH values should be controlled in the range of 9-11 to form the stable precipitation. The XRD investigation was used to further confirm the formation of the composite on specific pH values. In addition, the morphological study revealed that the average particle size of the composite decreased from 40 nm to 30 nm when the pH value increased from 9-11. The variation of microstructure plays a critical role in controlling the electromagnetic properties. From the electromagnetic analysis, the dielectric loss factor was 0.02-0.07 and magnetic loss factor was 0.2-0.5 for the composite synthesized at pH of 9, which presents dramatically improved dielectric loss and magnetic loss properties than the samples prepared at pH of 10 and 11. The as-prepared cobalt zinc ferrite are highly promising to be used as microwave absorption materials.

  11. Experimental Investigation of the Coprecipitation Method: An Approach to Obtain Magnetite and Maghemite Nanoparticles with Improved Properties

    Directory of Open Access Journals (Sweden)

    Wilson Sacchi Peternele

    2014-01-01

    Full Text Available Iron oxides that exhibit magnetic properties have been widely studied not only from an academic standpoint, but also for numerous applications in different fields of knowledge, such as biomedical and technological research. In this work, magnetite and maghemite nanoparticles were synthesized by chemical coprecipitation of FeCl2·4H2O and FeCl3·6H2O (proportion of 1 : 2 in three different cases using two bases (sodium hydroxide and hydroxide ammonium as precipitants. The chemical coprecipitation method was selected for its simplicity, convenience, reproducibility, and low cost in the use of glassware. The nanostructured materials were characterized by transmission electron microscopy (TEM, X-ray diffraction (XRD and magnetometry (VSM. The objective of this work is to study the variation in the morphological characteristics and physical properties of nanoparticles magnetic as a function of the different production processes. As observed by TEM, the materials obtained from the precipitating agent NH4OH are more uniform than those obtained with NaOH. From XRD pattern analysis, it appears that the obtained materials correspond to magnetite and maghemite and, from magnetometry VSM analysis, show high magnetization as a function of the magnetic field at room temperature, indicating that these materials are superparamagnetic.

  12. Filtration des fluides de forage à travers les parois du puits - Bibliographie Filtration of Drilling Fluids Through Borehole Walls

    Directory of Open Access Journals (Sweden)

    Martin M.

    2006-11-01

    Full Text Available Ce document résume un certain nombre de données déjà publiées, relatives à la filtration du fluide de forage, de l'annulaire vers les formations traversées, durant l'approfondissement du puits. On considère : - d'une part, les phénomènes de filtration : . le long des parois (filtration dynamique durant les périodes de circulation - filtration statique durant les arrêts, . sous l'outil ; - d'autre part, certaines de leurs conséquences, en particulier leur influence : . sur la vitesse d'avancement, . sur les risques de coincement de la garniture par pression différentielle, . sur l'envahissement des zones poreuses et perméables. Les phénomènes et leurs conséquences dépendent de très nombreux facteurs dont certains jouent des rôles d'importance très voisine. Leurs études nécessitent des moyens expérimentaux bien adaptés, permettant une simulation suffisamment rigoureuse des conditions de forage. Les résultats ne peuvent être généralisés et doivent être exprimés en fonction des paramètres opératoires choisis. This article reviews varions data which have already been published and which concern the filtration of drilling fluid from the annular space into the formations crossed through during the drilling of a borehole. The following aspects are considered: (i filtration phenomena along borehole walls (dynamic filtration during circulation, and static filtration during shutdowns and underneath the bit; (ii some of the consequences of this filtration, and especially its influence on the rate of penetration, on risks of drill string sticking as the result of differential pressure, and on the invasion of porous and permeable zones. Such phenomena and their consequences depend on a great many factor, some which play roles of quite similar importance. Resaerch on such phenomena requires well suited experimental facilities enabling the sufficiently cllose simulation of drilling conditions. the results of such research

  13. EX-PRESS Glaucoma Filtration Device: efficacy, safety, and predictability.

    Science.gov (United States)

    Chan, Jessica E; Netland, Peter A

    2015-01-01

    Trabeculectomy has been the traditional primary surgical therapy for open-angle glaucoma. While trabeculectomy is effective in lowering intraocular pressure, complications associated with the procedure have motivated the development of alternative techniques and devices, including the EX-PRESS Glaucoma Filtration Device. This review describes the efficacy, safety, complication rates, and potential advantages and disadvantages of the EX-PRESS Glaucoma Filtration Device. EX-PRESS implantation is technically simpler compared with that of trabeculectomy, with fewer surgical steps. Vision recovery has been more rapid after EX-PRESS implantation compared with trabeculectomy. Intraocular pressure variation is lower during the early postoperative period, indicating a more predictable procedure. While efficacy of the EX-PRESS implant has been comparable to trabeculectomy, postoperative complications appear less common after EX-PRESS implantation compared with trabeculectomy. The EX-PRESS Glaucoma Filtration Device appears to be safe and effective in the surgical management of open-angle glaucoma.

  14. The Fundamentals of Waste Water Sludge Characterization and Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Scales, Peter J.; Dixon, David R.; Harbour, Peter J.; Stickland, Anthony D.

    2003-07-01

    The move to greater emphasis on the disposal of waste water sludges through routes such as incineration and the added cost of landfill emplacement puts high demands on dewatering technology for these sludges. A dear problem in this area is that waste water sludges are slow and difficult to dewater and traditional methods of laboratory measurement for prediction of filtration performance are inadequate. This is highly problematic for the design and operational optimisation of centrifuges, filters and settling devices in the waste water industry. The behaviour is assessed as being due to non-linear behaviour of these sludges which negates the use of classical approaches. These approaches utilise the linear portion of a t versus V{sup 2} plot (where t is the time to filtration and V is the specific filtrate volume) to extract a simple Darcian permeability. Without this parameter, a predictive capacity for dewatering using current theory is negated. (author)

  15. Effects of drinking-water filtration on Cryptosporidium seroepidemiology, Scotland.

    Science.gov (United States)

    Ramsay, Colin N; Wagner, Adam P; Robertson, Chris; Smith, Huw V; Pollock, Kevin G J

    2014-01-01

    Continuous exposure to low levels of Cryptosporidium oocysts is associated with production of protective antibodies. We investigated prevalence of antibodies against the 27-kDa Cryptosporidium oocyst antigen among blood donors in 2 areas of Scotland supplied by drinking water from different sources with different filtration standards: Glasgow (not filtered) and Dundee (filtered). During 2006-2009, seroprevalence and risk factor data were collected; this period includes 2007, when enhanced filtration was introduced to the Glasgow supply. A serologic response to the 27-kDa antigen was found for ≈75% of donors in the 2 cohorts combined. Mixed regression modeling indicated a 32% step-change reduction in seroprevalence of antibodies against Cryptosporidium among persons in the Glasgow area, which was associated with introduction of enhanced filtration treatment. Removal of Cryptosporidium oocysts from water reduces the risk for waterborne exposure, sporadic infections, and outbreaks. Paradoxically, however, oocyst removal might lower immunity and increase the risk for infection from other sources.

  16. EFFECT OF KIESELGUHR FILTRATION ON OPTICAL PROPERTIES OF BEER

    Directory of Open Access Journals (Sweden)

    Helena Frančáková

    2013-02-01

    Full Text Available Looks of beer is an important factor which is associated with high clarity. Clarity of beer is a basic precondition of its good marketability and consumer satisfaction. Beer filtration is ideal tool to create required optical properties. There is a high accent on this operation in brewery and minibrewery. The process of filtering removes unwanted haze-active substances in order to increase clarity and overall stability of beer. Objective method to expressing clarity of beer is nephelometric determination of turbidity, which is highly sensitive and achieved by reliable results directly in the units used to express the turbidity values in beer. The objective of our study was to measure haze before and after filtration in various types of beer with different length of lagering. Kieselguhr was used as filtration material. Haze of beer was measured by haze meter in determination under 2 angles and values were expressed in European Brewery Convention units directly.

  17. EVALUATION OF EFFECTIVENESS OF HOUSEHOLD DRINKING WATER FILTRATION

    Directory of Open Access Journals (Sweden)

    Karolina Jezierska

    2014-10-01

    Full Text Available The aim of this study was to analyze the effectiveness of household drinking water filtration. This article demonstrates the possibilities of using study on the reaction of ascorbic acid degradation in aqueous solutions to develop a new method for determining the effectiveness of household drinking water filtration. Based on the measurements of absorbance of ascorbic acid a new parameters WCW (Coeffi cient of Water Purity and SF (Filtration Degree were defined. Correlations between the SF and the amount of filtered water (filter usage were investigated. With the filter usage decreasing effectiveness of calcium ions removal and drop of differences in conductivity between the tap and filtered water were observed. SF decreases proportionally to the filter usage and therefore the proposed method can be an effective tool to determine the effectiveness of domestic water filters.

  18. The renal handling of hemoglobin. I. Glomerular filtration.

    Science.gov (United States)

    Bunn, H F; Esham, W T; Bull, R W

    1969-05-01

    The glomerular filtration of hemoglobin (alpha(2)beta(2)) was studied under conditions in which its dissociation into alphabeta dimers was experimentally altered. Rats receiving hemoglobin treated with the sulfhydryl reagent bis(N-maleimidomethyl) ether (BME) showed a much lower renal excretion and prolonged plasma survival as compared with animals injected with untreated hemoglobin. Plasma disappearance was also prolonged in dogs receiving BME hemoglobin. Gel filtration data indicated that under physiological conditions, BME hemoglobin had impaired subunit dissociation. In addition, BME hemoglobin showed a very high oxygen affinity and a decreased rate of auto-oxidation. Glomerular filtration was enhanced under conditions which favor the dissociation of hemoglobin into dimers. Cat hemoglobin, which forms subunits much more extensively than canine hemoglobin, was excreted more readily by the rat kidney. The renal uptake of (59)Fe hemoglobin injected intra-arterially into rabbits varied inversely with the concentration of the injected dose.

  19. Deashing of coal liquids by sonically assisted filtration

    Energy Technology Data Exchange (ETDEWEB)

    Slomka, B.J.

    1994-10-01

    This project seeks to improve the effectiveness and reduce the cost of coal liquefaction by novel applications of sonic and ultrasonic energy. The specific purpose of this project is to develop and improve means for the economical removal of dispersed solid particles of ash, unreacted coal, and spent catalyst from direct and indirect coal liquefaction resids by using sonic or ultrasonic waves. Product streams containing solids are generated in both direct and indirect coal liquefaction processes. Direct coal liquefaction processes generate liquid products which contain solids including coal-originated mineral matter, unreacted coal, and spent dispersed catalyst. The removal of these solids from a product stream is one of the most difficult problems in direct coal liquefaction processes. On this report, results are discussed for sonically assisted crossflow filtration of V-1067 resid, diluted with No. 2 fuel oil, and sonically assisted batch filtrations of solids concentrates from continuous cross-flow filtration experiments.

  20. A novel insight into membrane fouling mechanism regarding gel layer filtration: Flory-Huggins based filtration mechanism.

    Science.gov (United States)

    Lei, Qian; Zhang, Meijia; Shen, Liguo; Li, Renjie; Liao, Bao-Qiang; Lin, Hongjun

    2016-09-15

    This study linked the chemical potential change to high specific filtration resistance (SFR) of gel layer, and then proposed a novel membrane fouling mechanism regarding gel layer filtration, namely, Flory-Huggins based filtration mechanism. A mathematical model for this mechanism was theoretically deduced. Agar was used as a model polymer for gel formation. Simulation of the mathematical model for agar gel showed that volume fraction of polymer and Flory-Huggins interaction parameter were the two key factors governing the gel SFR, whereas, pH and ionic strength were not related with the gel SFR. Filtration tests of gel layer showed that the total SFR value, effects of pH and ionic strength on the gel SFR well agreed with the perditions of model's simulation, indicating the real occurrence of this mechanism and the feasibility of the proposed model. This mechanism can satisfactorily explain the extremely high SFR of gel layer, and improve fundamental insights into membrane fouling regarding gel layer filtration.

  1. A novel insight into membrane fouling mechanism regarding gel layer filtration: Flory-Huggins based filtration mechanism

    Science.gov (United States)

    Lei, Qian; Zhang, Meijia; Shen, Liguo; Li, Renjie; Liao, Bao-Qiang; Lin, Hongjun

    2016-09-01

    This study linked the chemical potential change to high specific filtration resistance (SFR) of gel layer, and then proposed a novel membrane fouling mechanism regarding gel layer filtration, namely, Flory-Huggins based filtration mechanism. A mathematical model for this mechanism was theoretically deduced. Agar was used as a model polymer for gel formation. Simulation of the mathematical model for agar gel showed that volume fraction of polymer and Flory-Huggins interaction parameter were the two key factors governing the gel SFR, whereas, pH and ionic strength were not related with the gel SFR. Filtration tests of gel layer showed that the total SFR value, effects of pH and ionic strength on the gel SFR well agreed with the perditions of model’s simulation, indicating the real occurrence of this mechanism and the feasibility of the proposed model. This mechanism can satisfactorily explain the extremely high SFR of gel layer, and improve fundamental insights into membrane fouling regarding gel layer filtration.

  2. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  3. Pathogen filtration to control plant disease outbreak in greenhouse production

    Science.gov (United States)

    Jeon, Sangho; Krasnow, Charles; Bhalsod, Gemini; Granke, Leah; Harlan, Blair; Hausbeck, Mary; Zhang, Wei

    2016-04-01

    Previous research has been extensively focused on understanding the fate and transport of human microbial pathogens in soil and water environments. However, little is known about the transport of plant pathogens, although these pathogens are often found in irrigation waters and could cause severe crop damage and economical loss. Water mold pathogens including Phytophthora spp. and Pythium spp. are infective to a wide range of vegetable and floriculture crops, and they are primarily harbored in soils and disseminated through water flow. It is challenging to control these pathogens because they often quickly develop resistance to many fungicides. Therefore, this multi-scale study aimed to investigate physical removal of plant pathogens from water by filtration, thus reducing the pathogen exposure risks to crops. In column-scale experiments, we studied controlling factors on the transport and retention of Phytophthora capsici zoospores in saturated columns packed with iron oxide coated-sand and uncoated-sand under varying solution chemistry. Biflagellate zoospores were less retained than encysted zoospores, and lower solution pH and greater iron oxide content increased the retention of encysted zoospores. These results provided insights on environmental dispersal of Phytophthora zoospores in natural soils as well as on developing cost-effective engineered filtration systems for pathogen removal. Using small-scale greenhouse filtration systems, we further investigated the performance of varying filter media (i.e., granular sand, iron oxide coated ceramic porous media, and activated carbon) in mitigating disease outbreaks of Phytophthora and Pythium for greenhouse-grown squash and poinsettia, respectively, in comparison with fungicide treatment. For squash, filtration by iron oxide coated media was more effective in reducing the Phytophthora infection, comparing to sand filtration and fungicide application. For poinsettia, sand filtration performed better in controlling

  4. Depot effect of bioactive components in experimental membrane filtrations

    Science.gov (United States)

    Mitev, D.; Peshev, D.; Peev, G.; Peeva, L.

    2017-01-01

    Depot effects were found to be accompanying phenomena of membrane separation processes. Accumulation of target species in the membrane matrix during feasibility tests can hamper proper conclusions or compromise the filtration results. Therefore, we investigated the effects of delayed membrane release of chlorogenic acid and caffeine, considered as key compounds of interest in spent coffee products’ recovery treatment. Permeate fluxes and key components release were studied in course of 24 hours via nanofiltration of pure solvent, both immediately after the mock solution filtration and after idle stay. Conclusions are drawn and recommendations advised for proper analysis of experimental data on membrane screening.

  5. Filtration ATF in automatic transmissions (AT of cars

    Directory of Open Access Journals (Sweden)

    Tadeusz Dziubak

    2014-03-01

    Full Text Available Functions and conditions of work of suction ATF filters are presented. Requirements ofATF filters are discussed. Sources of contaminations ATF are presented. ATF filtration system wascharacterized. Classification of ATF filters and their selection of design solutions are presented. Filtermaterials used for the production of ATF suction filters are presented and characterized. Conditions ofthe work of suction ATF filters were analyzed. Hydraulic and filtration characteristics are discussed.[b]Keywords: AT[/b] — automatic transmissions, ATF — automatic transmission fluid, ATF filter

  6. Scientific opinion on the assessment of a decontamination process for dioxins and dioxin-like PCBs in fish oil by physical filtration with activated carbon

    DEFF Research Database (Denmark)

    Petersen, Annette

    the amount of dioxins (polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs)) and dioxin-like polychlorinated biphenyls (DL-PCBs). All feed decontamination processes must comply with the acceptability criteria specified in the Commission Regulation (EU) 2015/786. The data......Following a request from the European Commission, the EFSA Panel on Contaminants in the Food Chain (CONTAM) provided a scientific opinion on the assessment of a decontamination process consisting in the adsorption with activated carbon and physical filtration of fish oil in order to reduce...

  7. Experimental study on dynamic gas adsorption

    Institute of Scientific and Technical Information of China (English)

    Qin Yueping; Wang Yaru; Yang Xiaobin; Liu Wei; Luo Wei

    2012-01-01

    In order to predict the actual adsorption amount as gas adsorption reaches the equilibrium,this research designed a dynamic gas adsorption experiment under constant temperature and pressure,and also studied the isopiestic adsorption characteristics of coal samples with same quality but different sizes.Through the experiment,the study found the adsorption-time changing relationships under different pressures of four different size samples.After regression analysis,we obtained the functional relationship between adsorption and time.According to this,the research resulted in the actual adsorption amount when gas adsorption reaches the equilibrium.In addition,the current study obtained the relationship between adsorption and pressure as well as the effect of the coal size to the adsorption rate.These results have great theoretical and practical significance for the prediction of gas amount in coal seam and gas adsorption process.

  8. High performance NiFe layered double hydroxide for methyl orange dye and Cr(VI) adsorption.

    Science.gov (United States)

    Lu, Yi; Jiang, Bin; Fang, Liang; Ling, Faling; Gao, Jiemei; Wu, Fang; Zhang, Xihua

    2016-06-01

    The NiFe layered double hydroxides (LDHs) with different mole ratio of Ni/Fe (4:1, 3:1, 7:3 and 1:1) were prepared by a simple coprecipitation method. The adsorption performance were evaluated by the removal of methyl orange (MO) dye and hexavalent chromium(VI) heavy metal ion. It is found that Ni4Fe1-LDH can remove more than 92% of MO in 10 min at the 10 mg/L MO initial concentration, and 97% of Cr(VI) in 1 h at 4 mg/L Cr2O7(2-) initial concentration. The saturated adsorption capacity of Ni4Fe1-LDH is found to be as large as 205.76 mg/g for MO and 26.78 mg/g for Cr(VI). The adsorption behavior of this new adsorbent is fitted well with Langmuir isotherm and the pseudo-second-order kinetic model, indicative of a monolayer and chemical adsorption that synergistically originates from exchangeable anions mechanism and layer charge density. Due to the excellent removal capacity of MO and Cr(VI), the NiFe-LDHs could be a promising adsorbent for wastewater treatment.

  9. Preparation of Cobalt-Molybdenum bimetallic oxides supported on alumina by Co-precipitation method%氧化铝负载Co-Mo双金属氧化物的共沉淀制备

    Institute of Scientific and Technical Information of China (English)

    张新波; 张斌; 张雅娟; 秦永华

    2012-01-01

    采用双溶剂体系(硝酸铝和硝酸钴的乙醇溶液与钼酸铵的碳酸铵水溶液)共沉淀制备了氧化铝负载Co-Mo双金属氧化物.研究了双溶剂体系中乙醇和水的体积比对共沉淀的影响,考察了老化时间对氧化物结构参数的影响,研究了焙烧温度对氧化物还原性能的影响.结果表明:乙醇和水体积比对钼酸根离子的沉淀有重要影响,为了保证钼酸根离子的完全沉淀,乙醇的体积要随着MoO3负载量的增加而提高;随着老化时间的增加,氧化物的比表面积先增加后下降,6h 老化的样品具有最大的比表面积;低温焙烧制得的氧化物较容易还原.%Cobalt-molybdenum bimetallic oxides supported on alumina were prepared by co-precipitation method with etha- nol-water binary solvent system,which is composed of ethanol solution of aluminium nitrate and cobalt nitrate, and aqueous solution of ammonium carbonate and ammonium molybdate. The effects of ethanol/water volume ratio and MoO3 loading ore the coprecipitation were invesitigated. X-ray diffraction ( XRD) , N2 physical adsorption and temperature programmed reduction (TPR) were employed to characterize the oxides. Results show that the precipitation of Mo7O246- ions was affected by the ethanol/water volume ratio and MoO3 loading. The volume of ethanol to guarantee the precipitation of Mo7O246~ ions should be increased with the increase of MoO, loading. The specific surface area firstly increased then decreased with the increase of aging time. The oxide with aging time of 6 h has the largest specific surface area. The oxides calcined at low temperature are reduced more easily than that calcined at high temperature.

  10. Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration

    Directory of Open Access Journals (Sweden)

    L. D. Sánchez

    2012-06-01

    Full Text Available This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF in a multi-stage filtration (MSF plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It strongly reduces the load of particulate material before the water enters in the slow sand filters (SSF and therewith avoids short filter runs and prevents early interruption in SSF operations. The removal efficiency of turbidity in the CF-UGF with coagulant was between 85 and 96%, whereas the average efficiency without coagulant dosing was 46% (range: 21–76%. Operating with coagulant also improves the removal efficiency for total coliforms, E-coli and HPC. No reduction was observed in the microbial activity of the SSF, no obstruction of the SSF bed was demonstrated and SSF runs were maintained between 50 and 70 days for a maximum head loss of 0.70 m. The most important advantage is the flexibility of the system to operate with and without coagulant according to the influent turbidity. It was only necessary for 20% of the time to operate with the coagulant. The CF-UGF unit represented 7% of total construction costs and the O&M cost for the use of coagulant represented only 0.3%.

  11. Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration

    Directory of Open Access Journals (Sweden)

    L. D. Sánchez

    2012-12-01

    Full Text Available This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF in a multi-stage filtration (MSF plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It strongly reduces the load of particulate material before the water enters in the slow sand filters (SSF and therewith avoids short filter runs and prevents early interruption in SSF operations. The removal efficiency of turbidity in the CF-UGF with coagulant was between 85 and 96%, whereas the average efficiency without coagulant dosing was 46% (range: 21–76%. Operating with coagulant also improves the removal efficiency for total coliforms, E-coli and HPC. No reduction was observed in the microbial activity of the SSF, no obstruction of the SSF bed was demonstrated and SSF runs were maintained between 50 and 70 days for a maximum head loss of 0.70 m. The most important advantage is the flexibility of the system to operate with and without coagulant according to the influent turbidity. It was only necessary for 20% of the time to operate with the coagulant. The CF-UGF unit represented 7% of total construction costs and the O&M cost for the use of coagulant represented only 0.3%.

  12. Method for Determination of Neptunium in Large-Sized Urine Samples Using Manganese Dioxide Coprecipitation and 242Pu as Yield Tracer

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2013-01-01

    A novel method for bioassay of large volumes of human urine samples using manganese dioxide coprecipitation for preconcentration was developed for rapid determination of 237Np. 242Pu was utilized as a nonisotopic tracer to monitor the chemical yield of 237Np. A sequential injection extraction...... to 100% and high separation capacity of processing up to 5 L of human urine samples. The MnO2 coprecipitation process is simple and straightforward in which a batch (8–12) of samples can be pretreated within 4 h (i.e.,

  13. A comparative study on heat dissipation, morphological and magnetic properties of hyperthermia suitable nanoparticles prepared by co-precipitation and hydrothermal methods

    Indian Academy of Sciences (India)

    Md Shariful Islam; Yoshihumi Kusumoto; Junichi Kurawaki; Md Abdulla-Al-Mamun; Hirotaka Manaka

    2012-12-01

    Magnetite (Fe3O4) nanoparticles were prepared by co-precipitation and hydrothermal methods and their phase transfer was done successfully to compare their performances in different aspects. Synthesized nanoparticles were characterized for XRD, FE–SEM, TEM, UV-Vis absorption (reflectance) spectra, magnetic hysteresis loops and a.c. magnetic field induced hyperthermia. The magnetic nanoparticles prepared by the co-precipitation method show superior performances in respect of heat dissipation capability, saturation of magnetization values and particle size when compared to those prepared by the hydrothermal method.

  14. Thermoluminescence and photoluminescence properties of NaCl:Mn, NaCL:Cu nano-particles produced using co-precipitation and sono-chemistry methods

    Science.gov (United States)

    Mehrabi, M.; Zahedifar, M.; Saeidi-Sogh, Z.; Ramazani-Moghaddam-Arani, A.; Sadeghi, E.; Harooni, S.

    2017-02-01

    The NaCl: Cu and NaCl: Mn nanoparticles (NPs) were produced by co-precipitation and sono-chemistry methods and their thermoluminescence (TL) and photoluminescence (PL) properties were studied. By decreasing the particles size a considerable increase in sensitivity of the samples to high dose gamma radiation was observed. The NPs produced by sono-chemistry method have smaller size, homogeneous structure, more sensitivity to high gamma radiation and less fading than of those produced by co-precipitation method.

  15. Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements.

    Science.gov (United States)

    Kasamatsu, Yoshitaka; Yokokita, Takuya; Toyomura, Keigo; Shigekawa, Yudai; Haba, Hiromitsu; Kanaya, Jumpei; Huang, Minghui; Ezaki, Yutaka; Yoshimura, Takashi; Morita, Kosuke; Shinohara, Atsushi

    2016-12-01

    To establish a new methodology for superheavy element chemistry, the coprecipitation behaviors of 34 elements with samarium hydroxide were investigated using multitracer produced by a spallation of Ta. The chemical reactions were rapidly equilibrated within 10s for many elements. In addition, these elements exhibited individual coprecipitation behaviors, and the behaviors were qualitatively related to their hydroxide precipitation behaviors. It was demonstrated that the ammine and hydroxide complex formations of superheavy elements could be investigated using the established method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Adsorption Desalination: A Novel Method

    KAUST Repository

    Ng, Kim Choon

    2010-11-15

    The search for potable water for quenching global thirst remains a pressing concern throughout many regions of the world. The demand for new and sustainable sources and the associated technologies for producing fresh water are intrinsically linked to the solving of potable water availability and hitherto, innovative and energy efficient desalination methods seems to be the practical solutions. Quenching global thirst by adsorption desalination is a practical and inexpensive method of desalinating the saline and brackish water to produce fresh water for agriculture irrigation, industrial, and building applications. This chapter provides a general overview of the adsorption fundamentals in terms of adsorption isotherms, kinetics, and heat of adsorption. It is then being more focused on the principles of thermally driven adsorption desalination methods. The recent developments of adsorption desalination plants and the effect of operating conditions on the system performance in terms of specific daily water production and performance ratio are presented. Design of a large commercial adsorption desalination plant is also discussed herein.

  17. Adsorption of Atenolol on Kaolinite

    Directory of Open Access Journals (Sweden)

    Yingmo Hu

    2015-01-01

    Full Text Available In this study the adsorption of atenolol (AT, a β-blocker, on kaolinite, a clay mineral of low surface charge, was investigated under varying initial AT concentration, equilibrium time, solution pH, ionic strength, and temperature conditions. The results showed that the amounts of AT uptake by kaolinite were close to its cation exchange capacity value and the AT adsorption was almost instantaneous, suggesting a surface adsorption. The adsorption was exothermic and the free energy of adsorption was small negative, indicating physical adsorption. The increase in ionic strength of the solution drastically reduced AT uptake on kaolinite. A significant reduction in AT uptake was found at solution pH below 5 or above 10. The FTIR results showed band shifting and disappearance for NH bending vibration and benzene ring skeletal vibration at 3360 and 1515 cm−1 and band splitting at 1412 and 1240 cm−1 attributed to C–N valence vibration coupled with NH bending vibrations and alkyl aryl ether linkage, suggesting the participation of NH, –O–, and benzene ring for AT adsorption on kaolinite.

  18. Surface modification influencing adsorption of red wine constituents: The role of functional groups

    Science.gov (United States)

    Mierczynska-Vasilev, Agnieszka; Smith, Paul A.

    2016-11-01

    The adsorption of wine constituents at solid surfaces is important in applications such as filtration and membrane fouling, binding to tanks and fittings and interactions with processing aids such as bentonite. The interaction of wine constituents with surfaces is mediated through adsorbed wine components, where the type of constituents, amount, orientation, and conformation are of consequence for the surface response. This study examines the effect of surface chemical functionalities on the adsorption of red wine constituents. Plasma-polymerized films rich in amine, carboxyl, hydroxyl, formyl and methyl functional groups were generated on solid substrates whereas, glycidyltrimethylammonium chloride was covalently attached to allylamine plasma-polymer modified surface and poly(sodium styrenesulfonate) was electrostatically adsorbed to an amine plasma-polymerized surface. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy. The ability of different substrates to adsorb red wine constituents was evaluated by quartz crystal microbalance and atomic force microscopy. The results showed that substrates modified with -SO3H and -COOH groups can adsorb more of the wine nitrogen-containing compounds whereas -NH2 and -NR3 groups encourage carbon-containing compounds adsorption. Red wine constituents after filtration were adsorbed in higher extend on -NR3 and -CHO surfaces. The -OH modified surfaces had the lowest ability to absorb wine components.

  19. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  20. Carbon nanomaterials for gas adsorption

    CERN Document Server

    Terranova, Maria Letizia

    2012-01-01

    Research in adsorption of gases by carbon nanomaterials has experienced considerable growth in recent years, with increasing interest for practical applications. Many research groups are now producing or using such materials for gas adsorption, storage, purification, and sensing. This book provides a selected overview of some of the most interesting scientific results regarding the outstanding properties of carbon nanomaterials for gas adsorption and of interest both for basic research and technological applications. Topics receiving special attention in this book include storage of H, purific