Literatura académica sobre el tema "Co based hydroxides"
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Artículos de revistas sobre el tema "Co based hydroxides"
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Balram, Anirudh, Jie Chao Jiang, Moisés Hernández Fernández y Dennis De Sheng Meng. "Nickel-Cobalt Double Hydroxide Decorated Carbon Nanotubes via Aqueous Electrophoretic Deposition towards Catalytic Glucose Detection". Key Engineering Materials 654 (julio de 2015): 70–75. http://dx.doi.org/10.4028/www.scientific.net/kem.654.70.
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In this work, we present a facile technique based on electrophoretic deposition (EPD) to produce transition metal hydroxide decorated carbon nanotubes (CNT) for electrochemical applications. We specifically explore the performance of nickel-cobalt hydroxides given their high activity, conductivity and stability as compared to the individual hydroxides. We exploit the high local pH at the negative electrodes during water-based EPD to form nanoparticles of nickel-cobalt hydroxides in situ on the CNT surface. We focus our work here on obtaining functional and conductive deposits on CNTs. The hydrophilic binderless deposits of Ni-Co double hydroxide decorated CNTs obtained here are used for non-enzymatic glucose detection. XPS data and electrochemical testing reveal difference in the deposited double hydroxide based on chronology of charging salt addition even at the same ratio. When cobalt and nickel salts are sequentially added at a ratio of 1:1, the deposited double hydroxides show excellent glucose sensitivity of ~3300μA/mM.cm2 at applied potential of 0.55V vs. Ag/AgCl reference electrode.
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Cysewska, Karolina, Maria Krystyna Rybarczyk, Grzegorz Cempura, Jakub Karczewski, Marcin Łapiński, Piotr Jasinski y Sebastian Molin. "The Influence of the Electrodeposition Parameters on the Properties of Mn-Co-Based Nanofilms as Anode Materials for Alkaline Electrolysers". Materials 13, n.º 11 (11 de junio de 2020): 2662. http://dx.doi.org/10.3390/ma13112662.
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In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a β-phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2·g−1, a pore volume of 0.0042 cm3·g−1, and high electrochemical stability with an overpotential deviation around 330–340 mV at 10 mA·cm−2geo for 70 h.
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He, Peng Cheng, Xiao Bo Ji, Qing Zhang, Yi Fei Liu y Wen Cong Lu. "Shape-Controlled Synthesis and Pattern Recognition of Core-Shell Co-Al Hydroxides Superstructures". Advanced Materials Research 1120-1121 (julio de 2015): 188–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.188.
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In this paper, the optimal projection recognition (OPR) developed in our lab has been used to find the regularities of forming core-shell Co-Al Hydroxides superstructures.The criteria for predicting core-shell Co-Al Hydroxides superstructures can be obtained by using OPR method among different kinds of pattern recognition diagrams. The new samples predicted to be core-shell Co-Al Hydroxides superstructures were designed by using the inverse projection based on the OPR method. The predicted results agreed well with our experiments. Therefore, the work presented is very useful in the shape-controlled synthesis of core-shell Co-Al Hydroxides superstructures.
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Xie, Yu-Long, Fa-Ping Ye y Su-Qin Zhao. "Preparation of magnetic Co–Fe layered double hydroxides and its adsorption properties for the removal of methyl orange". Journal of Chemical Research 47, n.º 1 (enero de 2023): 174751982211503. http://dx.doi.org/10.1177/17475198221150382.
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In this study, Co–Fe layered double hydroxides are prepared by a hydrothermal method. The Co–Fe layered double hydroxides are used as an adsorbent for the investigation of the thermodynamic parameters and adsorption kinetics of methyl orange from aqueous solution. The results show that adsorption is affected by adsorbent dosage, adsorption time, and temperature. The characteristics of samples are investigated using X-ray powder diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and N2 adsorption–desorption isotherms. The adsorption saturation level of Co–Fe layered double hydroxides on methyl orange is studied, with the results showing that the maximum uptake capacity for methyl orange is 10.21 mg g−1 based on Co–Fe layered double hydroxides. The adsorption kinetics of methyl orange is consistent with the Temkin isotherm equation and quasi-secondary kinetic model. Furthermore, separation is easily accomplished under the action of an applied magnetic field. The prepared Co–Fe layered double hydroxides can be applied as an effective adsorbent for decontamination of anionic dyes in industrial effluents.
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Buffet, Jean-Charles, Zoë R. Turner, Robert T. Cooper y Dermot O'Hare. "Ethylene polymerisation using solid catalysts based on layered double hydroxides". Polymer Chemistry 6, n.º 13 (2015): 2493–503. http://dx.doi.org/10.1039/c4py01742k.
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We report here the use of methylaluminoxane (MAO) modified aqueous miscible organic solvent treated (AMOST) layered double hydroxide, Mg6Al2(OH)16CO3·4H2O (AMO-Mg3Al-CO3) as a catalyst support system for the slurry phase polymerisation of ethylene using immobilised metallocene and non-metallocene metal complexes.
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Cui, Yan, Yuan Xue, Rui Zhang, Jian Zhang, Xing'ao Li y Xinbao Zhu. "Vanadium–cobalt oxyhydroxide shows ultralow overpotential for the oxygen evolution reaction". Journal of Materials Chemistry A 7, n.º 38 (2019): 21911–17. http://dx.doi.org/10.1039/c9ta07918a.
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Palapa, Neza Rahayu, Bakri Rio Rahayu, Tarmizi Taher, Aldes Lesbani y Risfidian Mohadi. "Kinetic Adsorption of Direct Yellow Onto Zn/Al and Zn/Fe Layered Double Hydroxides". Science and Technology Indonesia 4, n.º 4 (29 de octubre de 2019): 101. http://dx.doi.org/10.26554/sti.2019.4.4.101-104.
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Zn/Al and Zn/Fe layered double hydroxides has successfully synthesized by co-precipitation methods with molar ration 3:1. The samples were characterized using X-Ray Diffraction, Fourier Transform Infrared Spectroscopy and Surface Area using BET method. In this study, Zn/Al and Zn/Fe layered double hydroxides were used to remove direct yellow dye in aqueous solution. The experiments were carried out time variations with the aim of observing the kinetic studies. The results showed that the adsorption of direct yellow onto Zn/Al and Zn/Fe layered double hydroxides based on co-efficient correlation kinetic models more fit using pseudo-second-order than pseudo-first-order.
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Kovalenko, Vadym y Valerii Kotok. "The determination of synthesis conditions and color properties of pigments based on layered double hydroxides with Co as a guest cation". Eastern-European Journal of Enterprise Technologies 6, n.º 6 (114) (21 de diciembre de 2021): 32–38. http://dx.doi.org/10.15587/1729-4061.2021.247160.
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Nail polish, in particular gel polish, is the most commonly used cosmetic product. A component of the gel polish, which determines the consumer color characteristics of the gel polish. Layered double hydroxides (LDH) are promising pigments. To expand the range of colors and shades of pigments, the use of LDH with colored host and guest cations is promising. The parameters of synthesis and color characteristics of samples of Zn-Co and Cu-Co hydroxide pigments were studied. To obtain LDH with Co as a guest cation in the synthesis, the conversion of cobalt to the trivalent state was carried out at a temperature of 80 °C using oxidation with atmospheric oxygen or sodium hypochlorite. The oxidation efficiency was evaluated by X-ray phase analysis by the presence or absence of cobalt-containing phases. The color characteristics of the synthesized pigment samples were studied by spectroscopic measurement and calculation in RGB, CIELab, and LCH color models. The low efficiency of cobalt oxidation at the moment of Zn-Co LDH synthesis with atmospheric oxygen at an elevated synthesis temperature of 80 °C was shown, while cobalt was released as a separate Co3O4 phase. A higher efficiency of cobalt oxidation at the moment of synthesis using sodium hypochlorite with the formation of Zn-Co LDH was revealed. It is recommended to use the hypochlorite oxidation of Co2+ to Co3+ in the LDH synthesis with Co in the form of a guest cation. The formation of a separate phase of zinc oxide was found in both types of oxidation due to the thermal decomposition of zinc hydroxide. Comparative analysis of color characteristics showed that all samples have a brown color of different saturation. It was revealed that during the formation of Co-containing LDH, the lightness of the color decreases. Color saturation increases in the case of a colored host cation, such as Cu.
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XIANG, X., L. ZHANG, H. HIMA, F. LI y D. EVANS. "Co-based catalysts from Co/Fe/Al layered double hydroxides for preparation of carbon nanotubes". Applied Clay Science 42, n.º 3-4 (enero de 2009): 405–9. http://dx.doi.org/10.1016/j.clay.2008.04.004.
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Tian, Jing, Weixin Qian, Haitao Zhang, Hongfang Ma y Weiyong Ying. "Synthesis of methanol over highly dispersed Cu–Fe based catalysts derived from layered double hydroxides". RSC Advances 13, n.º 20 (2023): 13902–10. http://dx.doi.org/10.1039/d3ra01188g.
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In this paper, catalysts with different aluminum contents were prepared by a co-precipitation method using LDHs (layered double hydroxides) as the precursors through the adjustment of Cu2+ : Fe2+, and the catalysts were named LDO catalysts.
Tesis sobre el tema "Co based hydroxides"
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Duan, Yan. "Understanding the oxygen evolution reaction (OER) for Co based transition metal oxides / hydroxides in alkaline electrolytes". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS416.
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Le développement d'électrocatalyseurs efficaces pour la réaction de libération d'oxygène (OER) est important pour améliorer l'efficacité globale du processus d'électrolyse de l'eau. Les oxydes / hydroxydes de métaux de transition présentent une activité et une stabilité raisonnables lorsqu’utilisés dans un milieu alcalin. Ils ont le potentiel de remplacer les oxydes à base d'Ir et de Ru. Comprendre la réaction d’OER pour les oxydes / hydroxydes de métaux de transition dans les électrolytes alcalins aide à la conception d'électrocatalyseurs peu coûteux et très efficaces. Avec trois travaux différents sur les oxydes / hydroxydes à base de Co, cette thèse approfondit la compréhension des propriétés de surface des matériaux et des propriétés interfaciales sur la cinétique de la réaction d’OER. Tout d'abord, la substitution au fer régule par exemple la configuration des cations métalliques dans LaCoO3. Cela ajuste la covalence de la liaison oxygène 2p – métal 3d et améliore les performances. Deuxièmement, la substitution au Ni dans ZnCo2O4 modifie la position relative du centre de la bande O 2p et du centre de la bande métallique dans un environnement octahédrique MOh. Cela modifie la stabilité et la possibilité pour l'oxygène du réseau de participer à la réaction de dégagement d’oxygène. Enfin, en étudiant les séries La1-xSrxCoO3, CoOOH et CoOOH contenant Fe, l'impact de l'électrolyte sur les paramètres de la cinétique de réaction a été exploré. Avec une meilleure compréhension de la façon dont les propriétés des matériaux et l'environnement dynamique influencent l'activité et le mécanisme des OER, nous pouvons obtenir des catalyseurs de OER plus efficaces pour une meilleure infrastructure énergétiqueThe development of efficient electrocatalysts to lower the overpotential of oxygen evolution reaction (OER) is of fundamental importance in improving the overall efficiency of fuel production by water electrolysis. Among a plethora of catalysts being studied on, transition metal oxides / hydroxides that exhibit reasonable activity and stability in alkaline electrolyte have been identified as catalysts to potentially overpass the activity of expensive Ir- and Ru- based oxides. Understanding the OER for transition metal oxides / hydroxides in alkaline electrolytes paves the way for better design of low cost and highly efficient electrocatalysts. This dissertation, with three different work on Co-based oxides / hydroxides, studies and deepens the understanding of the bulk properties, surface properties of materials and interfacial properties on OER. Firstly, with Fe substitution, it addresses tuning the eg configuration of metal cations in LaCoO3 where adjusting the metal 3d oxygen 2p covalency can bring benefits to the OER performance. Secondly, with Ni substitution in ZnCo2O4, it demonstrates a change in relative position of O p-band and MOh d-band centre which induces a change in stability as well as the possibility for lattice oxygen to participate in the OER. Finally, with La1-xSrxCoO3 series, CoOOH and Fe-containing CoOOH as examples, the impact of the electrolyte has been explored by the study of reaction kinetics parameters. With a better understanding of how material properties and dynamic environment influence the OER activity and mechanism, we can obtain more efficient OER catalysts for better energy infrastructure
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Masikhwa, Tshifhiwa Moureen. "Synthesis and characterization of Co-based hydroxides and metal disulphides with various forms of carbon for supercapacitor applications". Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/60837.
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The aim and objectives of this work are to synthesize cobalt-based hydroxides and transition metal disulphides composites with carbon materials such as graphene foam and activated carbon by a facile and environmentally friendly hydrothermal technique for energy storage application. Because faradaic materials suffer from poor electrical conductivity and low electrochemical stability, while carbon materials are known to have good electrical conductivity and electrochemical stability, the combination of the two materials to make hybrid material should be able to improve the electrochemical properties of the composite material. Morphological, structural, surface area and compositions properties of the produced materials were evaluated and characterized using methods such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherm (BET), Fourier transformation infrared spectroscopy (FTIR) and Raman spectroscopy. Electrochemical characterization involved cycling voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling life were carried out in two (asymmetric device) and three-electrode configurations using 6 M KOH aqueous electrolyte and they all showed excellent electrochemical performance. For instance the asymmetric devices based on CoA-LDH/graphene foam//AEG gave specific capacitance of 101.4 F g-1 with a maximum energy density of 28 Wh kg-1 and a corresponding power density of 1420 W kg-1 at a current density of 0.5 A g-1 , VS2//AC gave specific capacity of 155 F g-1 and high energy and power densities of 42 Wh kg-1 and 700 W kg-1 respectively at current density of 1 A g-1.and MoS2_150 mg GF //AEG gave high specific capacitance of 59 F g-1 with maximum energy and power densities of 16 Wh kg-1 and 758 W kg-1 respectively at a current density of 1 A g-1 respectively . All these results showed the great potential of the hybrid materials derived from the incorporation of cobalt based hydroxides and transition metal disulphides with carbon for supercapacitor application.Thesis (PhD)--University of Pretoria, 2016.
Physics
PhD
Unrestricted
Capítulos de libros sobre el tema "Co based hydroxides"
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Yartys, V., I. Zavaliy, A. Kytsya, V. Berezovets, Yu Pirskyy, F. Manilevich, Yu Verbovytskyy y P. Lyutyy. "Ni-, Co- and Pt-based nanocatalysts for hydrogen generation via hydrolysis of NaBH4". En HYDROGEN BASED ENERGY STORAGE: STATUS AND RECENT DEVELOPMENTS, 94–104. Institute for Problems in Materials Science, 2021. http://dx.doi.org/10.15407/materials2021.094.
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Ni-, Co- and Pt-based nanostructures were prepared via different physical-chemical methods and tested as the catalysts of hydrolysis of NaBH4. Ni-Co bimetallic nanoparticles with different Ni-Co ratios were synthesized by the modified polyol method via the reduction of in situ precipitated slurries of Ni and Co hydroxides by hydrazine in ethylene glycol solutions. It was found that a Ni- Co nanoparticles with the equal Ni/Co content and mean size of 130 nm are a more active catalyst as compared to Ni75Co25 and Ni25Co75 nanopowders and provide a constant rate of hydrogen evolution up to the full conversion of NaBH4. Zeolite supported Ni- and Co-based nanostructures (Ni-Z and Co-Z) as a convenient in use alternative to the metallic nanoparticles were synthesized via two-stage procedure consisted of adsorption of Ni2+ or Co2+ ions by zeolite from the aqueous solutions followed by the reduction of the adsorbed cations by NaBH4. Using SEM and EDX it was found that such method of synthesis provide the uniform distribution of 50 – 100 nm metallic nanopaticles both on the surface and in the bulk of the carrier due to the high cation-exchange capacity of the aluminosilicates. It was found that Co-Z catalyst is more active compared to Ni-Z and in studied conditions provides the H2 evolution rate close to 1450 mL/min per 1 g of precipitated metal. Various Pt-based nanocomposites were obtained by polyol synthesis and subsequently deposited on the carriers (carbon cloth or cordierite) as well as via a platinum electrodeposition on the titanium crump. It was found that the most efficient catalyst of the hydrolysis of NaBH4 is a cordierite-supported nanodispersed Pt which is able to maintain operation of a 30 W battery of fuel cells for 9-10 hours when using for the hydrolysis 1.1 L of 10 % NaBH4 solution.
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Atkins, Peter. "Carbon Footprints: The Wittig Reaction". En Reactions. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199695126.003.0026.
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As a molecular architect working on an atomic construction site you need to be able to build up the carbon skeleton of your project, not merely decorate it with foreign atoms. There are dozens of different ways of doing that, and in this and the next section I shall introduce you to just two of them to give you a taste of what is available. A secondary point is that throughout chemistry you will find reactions denoted by proper nouns, recognizing the chemists who have invented or developed them. One example is that of the ‘Wittig reaction’, which is named after the German chemist Georg Wittig (1897–1987; Nobel Prize 1979). The reaction is used to replace the oxygen atom of a CO group in a molecule by a carbon atom, so that what starts out as decoration becomes part of a growing network of carbon atoms. You need to know that phosphine, PH3, 1, the phosphorus cousin of ammonia, NH3, is a base (Reaction 2). When it accepts a proton it becomes the ion PH4+. The H atoms in that ion can be replaced with other groups of atoms. A replacement that will be of interest is when three of the H atoms have been replaced by benzene rings and the remaining H atom has been replaced by –CH3. The resulting ion is 2. In the presence of a base, such as the hydroxide ion, OH–, the –CH3 group can be induced to release one of its protons, so the positive ion becomes the neutral molecule, 3. Note that there is a partial positive charge on the P atom and a partial negative charge on the C atom of the CH2 group. The presence of that partial negative charge suggests that the species could act as a nucleophile (Reaction 15), a seeker out of positive charge, with the CH2 group the charge-seeking head of the missile. Let’s watch what happens when 3 attacks a molecule with a CO group, specifically 4: perhaps you want to sprout a carbon chain out from the ring and intend to begin by replacing the O atom with a C atom.
Actas de conferencias sobre el tema "Co based hydroxides"
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Agourrame, Hind, Amine Belafhaili, Nisrine El Fami, Nacer Khachani, Mohamed Alami Talbi, Ali Boukhari y Adeljebbar Diouri. "Stabilization of Dicalcium Silicate-Zn Composite Approaching Layered Double Hydroxide Structure for Bioactive Cement Applications". En 4th International Conference on Bio-Based Building Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.668.
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Layered Double Hydroxide (LDH) is ionic clay that is characterized by the union of metal cations and OH- hydroxides. LDH composites exhibit considerably high releasing and recharging capacity and have applications as bioactive cements. They can be prepared by direct co-precipitation of metal salts at controlled pH. The preparation is carried out from an acid solution of Zn (NO3)2.6H2O, Al (NO3)3.9H2O and a basic solution of Na2CO3 and NaOH, with a Zn/Al ratio = 3, the pH is stabilized between 9 and 9.5 at a constant temperature of 45°C. The objective of this study is to incorporate Zinc and Aluminum elements at different percentages in dicalcium silicate phase to produce C2S phase incorporating LDH composite. The characterizations of the developed phases by XRD and SEM indicate the formation of stoichiometric LDH phases Zn6Al2(OH)16CO3.4H2O and non-stoichiometric Zn0.61Al0.39 (OH)2(CO3)0.195.xH2O, the incorporation of Zn in the belitic C2S phase and not Al. The obtained micrographs by SEM(EDAX) analysis show new morphology of the stabilized composite.
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Nuckols, M., S. Kolaczkowski, S. Awdry, T. Smith y D. Thomas. "Hyperbaric Testing of an Alternative Approach to Remove Carbon Dioxide From Underwater Life Support Equipment". En ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23028.
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Traditional CO2 absorption methods for underwater life support equipment use alkali metal hydroxide chemical beds — mostly calcium hydroxide — that have been shown to have poor absorption efficiencies at cold temperatures, and must be replaced at considerable trouble and expense on a frequent basis. With chemical utilizations as low as 20% in water temperatures of 2°C, these hydroxides do not lend themselves to applications requiring extended durations in cold water due to the inability to carry sufficient quantities of expendables. A joint research effort between Duke University and the University of Bath has verified the feasibility in laboratory trials of an alternative carbon dioxide removal method that intimately mixes seawater with breathing circuit gases within a packed bed of Dixon rings. Based on the results of these laboratory trials, two multi-path scrubber prototypes were designed and fabricated for unmanned testing. In March 2013, the hyperbaric performance of these prototype scrubbers was characterized over a wide range of gas and water flow rates when operating the scrubbers in counter-current (water flowing in the opposite direction as gas flow) and co-current (water flowing in the same direction as gas flow) fashion. Significant findings from these tests included the following: • Both scrubber prototypes were found to be capable of delivering exit CO2 levels below 0.5 vol% (surface equivalent) at respiratory rates up to 22.5 liters per minute and at depths ranging from 0 to 40 meters of seawater (MSW). • Negligible collateral O2 absorption was observed at surface pressure (exit O2 levels were typically above 20.2 vol%), and exit O2 levels were typically above 18.4% during testing at 10 MSW. • At surface pressure, both prototypes had significantly lower breathing resistances than design goals established by the U. S. Navy.
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Pashkevich, Yurii, Vladimir Gnezdiov, Daniel E. L. Vieira, Roman Babkin, Irina Lukienko, Joaquim M. Vieira, Dirk Wulferding, Peter Lemmens y Andrei N. Salak. "Comparative Optic Studies of Cobalt-Based Layered Double Hydroxides with Nitrate and Carbonate Anions and CoII/A1III ratio n = 2, 3, 4". En 2021 IEEE 11th International Conference Nanomaterials: Applications & Properties (NAP). IEEE, 2021. http://dx.doi.org/10.1109/nap51885.2021.9568631.
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Abdalla, Mayar Tarek. "Iron Magnesium Coating Chicken Bones for Removal of Copper from Water". En GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219361-ms.
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Abstract Because heavy metals have detrimental effects on aquatic life and public health, their presence in freshwater sources is extremely concerning. Even in low quantities, copper (Cu), one of the most hazardous heavy metals, can result in major health problems. The current study seeks to create a novel adsorption medium using iron (Fe)-coated chicken bones Using magnesium hydroxides, copper can be eliminated from water. In which the chicken bones were treated with stacked double hydroxides (LDH) Physical adsorption is the process by which heavy metals from the waste liquid are adsorbed onto the chicken bone-based adsorbent. The cause of physical adsorption is an imbalance in the porous nature of the adsorbent surface, which draws the adsorbate (heavy metal) to the surface. The residue of inorganic materials left over after burning at temperatures higher than 575°C is known as ash. A substance is heated as part of the ash-making process, and the method involves drying, burning charcoal, and desolating volatile chemicals. Heat will be produced by burning the charcoal, volatile chemicals will evaporate, and moisture will be lost throughout the drying process. There will be an interaction between carbon and oxygen during the burning of charcoal to form co-gas, which then develops into CO2 gas so that in the end there will be only material known as ash. With a rough and porous surface shape, apatite carbonate compound minerals are a distinguishing feature of the adsorbent made from chicken bone ash. The adsorption performance can be improved by raising the ashing temperature, contact time, particle size, and weight of the adsorbent. The physical adsorption process is accelerated at near-neutral pH values. Adsorbents made of chicken bone ash can lower Cu metal levels while also improving waste quality. In this paper, Carbon-based adsorption is described as a traditional treatment with a high unit cost, particularly in underdeveloped nations.
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Rauscher, Sebastian. "Entwicklung in der Aufbereitungstechnik". En Bauen mit rezyklierten mineralischen Baustoffen - Von der Ausnahme zur Regelbauweise : 20. Symposium Baustoffe und Bauwerkserhaltung. KIT Scientific Publishing, 2024. http://dx.doi.org/10.58895/ksp/1000167485-2.
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The construction and recycling industry is currently in a phase of dynamic change. Driven by climate and resource policy measures, above all the Substitute Building Materials Ordinance introduced in Germany in August 2023, mass flows and treatment processes are shifting from construction sites to specialised recycling centres. The monitoring and documentation of mineral substitute building materials is a key aspect of the ordinance. Recycling companies can only return the increased masses and complex material compositions to the material cycle in high quality by using innovative processing technology. There is a wide range of options for processing, checking and treating secondary raw materials. Heinrich Feeß GmbH & Co. KG (Feess) is actively involved in research projects to explore innovative ways of processing technology and to overcome the challenges of practical application. This text highlights a selection of projects that Feess is currently working on. The promising project for the carbonation of old concrete will be presented. The process, which is based on the conversion of calcium hydroxide to calcium carbonate, can be used to bind environmentally harmful CO2 in recycled products. Carbonation is being implemented on an industrial scale and integrated into the logistical framework of a recycling site. Another project is concerned with the construction of an efficient building material sorting plant to produce high-quality recycled aggregates and increase the recycling rate. Feess was able to utilise its many years of experience in the recycling of mineral waste in the development of this plant. The aim is to maximise added value within an economical and practical framework. A third project, KreiSBau, focuses on the utilisation of the fine-grained mixed construction waste fraction in building construction. By reducing the sulphate content and developing RC construction products, the aim is to achieve a closed material cycle in order to increase resource efficiency and minimise the landfill rate. Overall, these research projects demonstrate Germany's endeavours to establish a sustainable circular economy in the construction sector by driving forward innovative technologies and processes in mineral waste processing.
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Chen, Kok Hao y Jong Hyun Choi. "DNA Oligonucleotide-Templated Nanocrystals: Synthesis and Novel Label-Free Protein Detection". En ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11958.
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Semiconductor and magnetic nanoparticles hold unique optical and magnetic properties, and great promise for bio-imaging and therapeutic applications. As part of their stable synthesis, the nanocrystal surfaces are usually capped by long chain organic moieties such as trioctylphosphine oxide. This capping serves two purposes: it saturates dangling bonds at the exposed crystalline lattice, and it prevents irreversible aggregation by stabilizing the colloid through entropic repulsion. These nanocrystals can be rendered water-soluble by either ligand exchange or overcoating, which hampers their widespread use in biological imaging and biomedical therapeutics. Here, we report a novel scheme of synthesizing fluorescent PbS and magnetic Fe3O4 nanoparticles using DNA oligonucleotides. Our method of PbS synthesis includes addition of Na2S to the mixture solution of DNA sequence and Pb acetate (at a fixed molar ratio of DNA/S2−/Pb2+ of 1:2:4) in a standard TAE buffer at room temperature in the open air. In the case of Fe3O4 particle synthesis, ferric and ferrous chloride were mixed with DNA in DI water at a molar ratio of DNA/Fe2+/Fe3+ = 1:4:8 and the particles were formed via reductive precipitation, induced by increasing pH to ∼11 with addition of ammonium hydroxide. These nanocrystals are highly stable and water-soluble immediately after the synthesis, due to DNA termination. We examined the surface chemistry between oligonucleotides and nanocrystals using FTIR spectroscopy, and found that the different chemical moieties of nucleobases passivate the particle surface. Strong coordination of primary amine and carbonyl groups provides the chemical and colloidal stabilities, leading to high particle yields (Figure 1). The resulting PbS nanocrystals have a distribution of 3–6 nm in diameter, while a broader size distribution is observed with Fe3O4 nanoparticles as shown in Figure 1b and c, respectively. A similar observation was reported with the pH change-induced Fe3O4 particles of a bimodal size distribution where superparamagnetic and ferrimagnetic magnetites co-exist. In spite of the differences, FTIR measurements suggest that the chemical nature of the oligonucleotide stabilization in this case is identical to the PbS system. As a particular application, we demonstrate that aptamer-capped PbS QD can detect a target protein based on selective charge transfer, since the oligonucleotide-templated synthesis can also serve the additional purpose of providing selective binding to a molecular target. Here, we use thrombin and a thrombin-binding aptamer as a model system. These QD have diameters of 3∼6 nm and fluoresce around 1050 nm. We find that a DNA aptamer can passivate near IR fluorescent PbS nanocrystals, rendering them water-soluble and stable against aggregation, and retain the secondary conformation needed to selectively bind to its target, thrombin, as shown in Figure 2. Importantly, we find that when the aptamer-functionalized nanoparticles binds to its target (only the target), there is a highly systematic and selective quenching of the PL, even in high concentrations of interfering proteins as shown in Figure 3a and b. Thrombin is detected within one minute with a detection limit of ∼1 nM. This PL quenching is attributed to charge transfer from functional groups on the protein to the nanocrystals. A charge transfer can suppress optical transition mechanisms as we observe a significant decrease in QD absorption with target addition (Figure 3c). Here, we rule out other possibilities including Forster resonance energy transfer (FRET) and particle aggregation, because thrombin absorb only in the UV, and we did not observe any significant change in the diffusion coefficient of the particles with the target analyte, respectively. The charge transfer-induced photobleaching of QD and carbon nanotubes was observed with amine groups, Ru-based complexes, and azobenzene compounds. This selective detection of an unlabeled protein is distinct from previously reported schemes utilizing electrochemistry, absorption, and FRET. In this scheme, the target detection by a unique, direct PL transduction is observed even in the presence of high background concentrations of interfering negatively or positively charged proteins. This mechanism is the first to selectively modulate the QD PL directly, enabling new types of label free assays and detection schemes. This direct optical transduction is possible due to oligonucleotidetemplated surface passivation and molecular recognition. This chemistry may lead to more nanoparticle-based optical and magnetic probes that can be activated in a highly chemoselective manner.