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Sample records for activated carbon-based adsorbents

  1. Development of novel activated carbon-based adsorbents for the control of mercury emissions from coal-fired power plants

    Radisav D. Vidic

    1999-03-01

    In addition to naturally occurring mercury sources, anthropogenic activities increase the mercury loading to the environment. Although not all produced mercury is dissipated directly into the environment, only minor portions of the total production are stocked or recycled, and the rest of the mercury and its compounds is finally released in some way into atmosphere, surface waters and soil, or ends in landfills dumps, and refuse. Since mercury and its compounds are highly toxic, their presence in the environment constitutes potential impact on all living organisms, including man. The first serious consequence of industrial mercury discharges causing neurological disorder even death occurred in Minimata, Japan in 1953. Systematic studies showed that mercury poisoning is mainly found in fish-eating populations. However, various levels of mercury are also found in food other than fish. During the past several decades, research has been conducted on the evaluation of risks due to exposure to mercury and the development of control technologies for mercury emissions. In 1990, the Clean Air Act Amendments listed mercury, along with 10 other metallic species, as a hazardous air pollutant (HAP). This has further stimulated research for mercury control during the past several years. The impact of mercury on humans, sources of mercury in the environment, current mercury control strategies and the objective of this research are discussed in this section.

  2. Carbon-Based Adsorbents for Postcombustion CO2 Capture: A Critical Review.

    Creamer, Anne Elise; Gao, Bin

    2016-07-19

    The persistent increase in atmospheric CO2 from anthropogenic sources makes research directed toward carbon capture and storage imperative. Current liquid amine absorption technology has several drawbacks including hazardous byproducts and a high-energy requirement for regeneration; therefore, research is ongoing to develop more practical methods for capturing CO2 in postcombustion scenarios. The unique properties of carbon-based materials make them specifically promising for CO2 adsorption at low temperature and moderate to high partial pressure. This critical review aims to highlight the development of carbon-based solid sorbents for postcombustion CO2 capture. Specifically, it provides an overview of postcombustion CO2 capture processes with solid adsorbents and discusses a variety of carbon-based materials that could be used. This review focuses on low-cost pyrogenic carbon, activated carbon (AC), and metal-carbon composites for CO2 capture. Further, it touches upon the recent progress made to develop metal organic frameworks (MOFs) and carbon nanomaterials and their general CO2 sorption potential. PMID:27257991

  3. Selective adsorption for removal of nitrogen compounds from hydrocarbon streams over carbon-based adsorbents

    Almarri, Masoud S.

    The ultimate goal of this thesis is to develop a fundamental understanding of the role of surface oxygen functional groups on carbon-based adsorbents in the adsorption of nitrogen compounds that are known to be present in liquid fuels. N2 adsorption was used to characterize pore structures. The surface chemical properties of the adsorbents were characterized by X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) techniques with a mass spectrometer to identify and quantify the type and concentration of oxygen functional groups on the basis of CO2 and CO evolution profiles. It was found that although surface area and pore size distribution are important for the adsorption process, they are not primary factors in the adsorption of nitrogen compounds. On the other hand, both the type and concentration of surface oxygen-containing functional groups play an important role in determining adsorptive denitrogenation performance. Higher concentrations of the oxygen functional groups on the adsorbents resulted in a higher adsorption capacity for the nitrogen compounds. A fundamental insight was gained into the contributions of different oxygen functional groups by analyzing the changes in the monolayer maximum adsorption capacity, qm, and the adsorption constant, K, for nitrogen compounds on different activated carbons. Acidic functional groups such as carboxylic acids and carboxylic anhydrides appear to contribute more to the adsorption of quinoline, while the basic oxygen functional groups such as carbonyls and quinones enhance the adsorption of indole. Despite the high number of publications on the adsorptive desulfurization of liquid hydrocarbon fuels, these studies did not consider the presence of coexisting nitrogen compounds. It is well-known that, to achieve ultraclean diesel fuel, sulfur must be reduced to a very low level, where the concentrations of nitrogen and sulfur compounds are comparable. The adsorptive denitrogenation and

  4. Antimicrobial Activity of Carbon-Based Nanoparticles

    Solmaz Maleki Dizaj

    2015-03-01

    Full Text Available Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs (especially single-walled carbon nanotubes (SWCNTs and graphene oxide (GO nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery.

  5. Effect of biomass addition on the surface and adsorption characterization of carbon-based adsorbents from sewage sludge

    Changzi Wu; Min Song; Baosheng Jin; Yimin Wu; Yaji Huang

    2013-01-01

    Sewage sludge with the additive corn cob was used as prescusor to prepare sludge-based carbon adsorbents by pyrolysis method.And then,the carbonizated products were activated with potassium hydroxide.The mixing ratio of the corn cob to sewage sludge was investigated.The surface area and pore size distribution,elemental composition,surface chemistry structure and the surface physical morphology were determined and compared.The results demonstrated that the addition of corn cob into the sewage sludge sample could effectively improve the surface area (from 287 to 591 m2/g) and the microporosity (from 5% to 48%) of the carbon based adsorbent,thus enhancing the adsorption behavior.The sulfur dioxide adsorption capacity was measured according to breakthrough test.It was found that the sulfur dioxide adsorption capacity of the adsorbents was obviously enhanced after the addition of the corn cob.It is presumed that not only highly porous adsorbents,but also a high metallic content of these materials are required to achieve good performances.

  6. Inorganic chemically active adsorbents (ICAAs)

    Ally, M.R. [Oak Ridge National Lab., TN (United States); Tavlarides, L.

    1997-10-01

    Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

  7. Evaluation of magnetic- and carbon-based nano-adsorbents application in pre-purification of paclitaxel from needles of Taxus baccata

    Naghavi, M. R., E-mail: mnaghavi@ut.ac.ir; Motamedi, E., E-mail: motamedi.elaheh@gmail.com; Nasiri, J., E-mail: jaber.nasiri@ut.ac.ir; Alizadeh, H., E-mail: halizade@ut.ac.ir [University of Tehran, Division of Molecular Plant Genetics, Department of Agronomy and Plant Breeding, College of Agricultural & Natural Resources (Iran, Islamic Republic of); Fattahi Moghadam, M. R., E-mail: fattahi@ut.ac.ir [University of Tehran, Department of Horticultural Sciences, College of Agricultural & Natural Resources (Iran, Islamic Republic of); Mashouf, A., E-mail: mashouf-alireza@yahoo.com [Shahid Beheshti University, Medicinal Plants and Drugs Research Institute (Iran, Islamic Republic of)

    2015-01-15

    In this investigation, the proficiency of a number of magnetic carbon-based nano-adsorbents is evaluated in pre-purification process of the crude paclitaxel extract obtained from fresh needles of yew tree (Taxus baccata L.). The effectiveness and removal ability of color and impurities from crude extracts, for three novel candidate nano-adsorbents (i.e., Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}Nps), graphite oxide (GO), and their hybrids Fe{sub 3}O{sub 4}Nps/GO) are compared with commercial graphite in three different solvents. In general, both HPLC and UV–Vis spectroscopy results demonstrate that in less polar solvent (i.e., dichloromethane), the adsorption is greatly affected by the electrostatic attractions, while in more polar solvents (i.e., acetone and ethanol) π–π electron interactions taking place between adsorbent and adsorbate are the most dominant factors in sorption. Considering decolorization efficiency, purity of taxol, recovery and reusability of adsorbents, Fe{sub 3}O{sub 4}Nps/GO (50 g/L) in dichloromethane is selected as the best medium for pre-purification of paclitaxel. Additionally, in kinetic studies the sorption equilibrium can be reached within 120 min, and the experimental data are well fitted by the pseudo-second-order model. The Langmuir sorption isotherm model correlates well with the sorption equilibrium data for the crude extract concentration (500–2,000 mg/L). Our findings display promising applications of Fe{sub 3}O{sub 4}Nps/GO, as a cost-effective nano-adsorbent, to provide a suitable vehicle toward improvement of paclitaxel pre-purification.

  8. Evaluation of magnetic- and carbon-based nano-adsorbents application in pre-purification of paclitaxel from needles of Taxus baccata

    In this investigation, the proficiency of a number of magnetic carbon-based nano-adsorbents is evaluated in pre-purification process of the crude paclitaxel extract obtained from fresh needles of yew tree (Taxus baccata L.). The effectiveness and removal ability of color and impurities from crude extracts, for three novel candidate nano-adsorbents (i.e., Fe3O4 nanoparticles (Fe3O4Nps), graphite oxide (GO), and their hybrids Fe3O4Nps/GO) are compared with commercial graphite in three different solvents. In general, both HPLC and UV–Vis spectroscopy results demonstrate that in less polar solvent (i.e., dichloromethane), the adsorption is greatly affected by the electrostatic attractions, while in more polar solvents (i.e., acetone and ethanol) π–π electron interactions taking place between adsorbent and adsorbate are the most dominant factors in sorption. Considering decolorization efficiency, purity of taxol, recovery and reusability of adsorbents, Fe3O4Nps/GO (50 g/L) in dichloromethane is selected as the best medium for pre-purification of paclitaxel. Additionally, in kinetic studies the sorption equilibrium can be reached within 120 min, and the experimental data are well fitted by the pseudo-second-order model. The Langmuir sorption isotherm model correlates well with the sorption equilibrium data for the crude extract concentration (500–2,000 mg/L). Our findings display promising applications of Fe3O4Nps/GO, as a cost-effective nano-adsorbent, to provide a suitable vehicle toward improvement of paclitaxel pre-purification

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

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

    2010-01-01

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

  10. Magnesium oxide nanoparticles on green activated carbon as efficient CO{sub 2} adsorbent

    Wan Isahak, Wan Nor Roslam; Ramli, Zatil Amali Che; Mohamed Hisham, Mohamed Wahab; Yarmo, Mohd Ambar [Low Carbon Economy (LCE) Research Group, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2013-11-27

    This study was focused on carbon dioxide (CO{sub 2}) adsorption ability using Magnesium oxide (MgO) nanoparticles and MgO nanoparticles supported activated carbon based bamboo (BAC). The suitability of MgO as a good CO{sub 2} adsorbent was clarified using Thermodynamic considerations (Gibbs-Helmholtz relationship). The ΔH and ΔG of this reaction were − 117.5 kJ⋅mol{sup −1} and − 65.4 kJ⋅mol{sup −1}, respectively, at standard condition (298 K and 1 atm). The complete characterization of these adsorbent were conducted by using BET, XRD, FTIR, TEM and TPD−CO{sub 2}. The surface areas for MgO nanoparticles and MgO nanoparticles supported BAC were 297.1 m{sup 2}/g and 702.5 m{sup 2}/g, respectively. The MgO nanoparticles supported BAC shown better physical and chemical adsorption ability with 39.8 cm{sup 3}/g and 6.5 mmol/g, respectively. The combination of MgO nanoparticle and BAC which previously prepared by chemical method can reduce CO{sub 2} emissions as well as better CO{sub 2} adsorption behavior. Overall, our results indicate that nanoparticles of MgO on BAC posses unique surface chemistry and their high surface reactivity coupled with high surface area allowed them to approach the goal as an efficient CO{sub 2} adsorbent.

  11. Magnesium oxide nanoparticles on green activated carbon as efficient CO2 adsorbent

    This study was focused on carbon dioxide (CO2) adsorption ability using Magnesium oxide (MgO) nanoparticles and MgO nanoparticles supported activated carbon based bamboo (BAC). The suitability of MgO as a good CO2 adsorbent was clarified using Thermodynamic considerations (Gibbs-Helmholtz relationship). The ΔH and ΔG of this reaction were − 117.5 kJ⋅mol−1 and − 65.4 kJ⋅mol−1, respectively, at standard condition (298 K and 1 atm). The complete characterization of these adsorbent were conducted by using BET, XRD, FTIR, TEM and TPD−CO2. The surface areas for MgO nanoparticles and MgO nanoparticles supported BAC were 297.1 m2/g and 702.5 m2/g, respectively. The MgO nanoparticles supported BAC shown better physical and chemical adsorption ability with 39.8 cm3/g and 6.5 mmol/g, respectively. The combination of MgO nanoparticle and BAC which previously prepared by chemical method can reduce CO2 emissions as well as better CO2 adsorption behavior. Overall, our results indicate that nanoparticles of MgO on BAC posses unique surface chemistry and their high surface reactivity coupled with high surface area allowed them to approach the goal as an efficient CO2 adsorbent

  12. Linear response theory of activated surface diffusion with interacting adsorbates

    Graphical abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed. - Abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed.

  13. Characterization and adsorption behavior of a novel triolein-embedded activated carbon composite adsorbent

    RU Jia; LIU Huijuan; QU Jiuhui; WANG Aimin; DAI Ruihua

    2005-01-01

    A novel triolein-embedded activated carbon composite adsorbent was developed. Experiments were carried out in areas such as the preparation method, the characterization of physicochemical properties, and the adsorption behavior of the composite adsorbent in removing dieldrin from aqueous solution. Results suggested that the novel composite adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. The adsorbent was stable in water, for no triolein leakage was detected after soaking the adsorbent for five weeks. The adsorbent had good adsorption capability to dieldrin, which was indicated by a residual dieldrin concentration of 0.204 μg·L-1. The removal efficiency of the composite adsorbent was higher than the traditional activated carbon adsorbent.

  14. Challenge to high-activity-level water treatment by adsorbents

    There are over 280,000 tonnes of contaminated water in the damaged Fukushima Daiichi Nuclear Plant site in various tanks and barges and a large amount of contaminated water is now producing at the rate of several tonnes/day owing to inevitable cooling of the reactor cores. SARRY (Simplified Active Water Retrieve and Recovery System) and ALPS (Advanced Liquid Processing System) are installed to remove Cs and multi-elements respectively utilizing ion exchangers (zeolite, crystalline silicon titanate, and metal ferrocyanides) from contaminated water. The author continues efforts to find effective and selective adsorbents for Cs and Sr by measuring partition data, adsorption isotherms and adsorption rate referring with chemical structure elucidated from X-ray diffraction and SEM techniques. The obtained data are presented. (S. Ohno)

  15. Study of the Adsorbent-Adsorbate Interactions from Cd(II) and Pb(II) Adsorption on Activated Carbon and Activated Carbon Fiber

    The adsorption characteristics of Cd(II) and Pb(II) in aqueous solution using granular activated carbon (GAC), activated carbon fiber (ACF), modified ACF (NaACF), and a mixture of GAC and NaACF (GAC/NaACF) have been studied. The surface properties, such as morphology, surface functional groups, and composition of various adsorbents were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The specific surface area, total pore volume, and pore size distribution were investigated using nitrogen adsorption, Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) methods. In this study, NaACF showed a high adsorption capacity and rate for heavy metal ions due to the improvement of its ion-exchange capabilities by additional oxygen functional groups. Moreover, the GAC and NaACF mixture was used as an adsorbent to determine the adsorbent-adsorbate interaction in the presence of two competitive adsorbents

  16. Preparation of ferric-activated sludge-based adsorbent from biological sludge for tetracycline removal.

    Yang, Xin; Xu, Guoren; Yu, Huarong; Zhang, Zhao

    2016-07-01

    Ferric activation was novelly used to produce sludge-based adsorbent (SBA) from biological sludge through pyrolysis, and the adsorbents were applied to remove tetracycline from aqueous solution. The pyrolysis temperature and mass ratio (activator/dried sludge) greatly influenced the surface area and pore characteristics of SBA. Ferric activation could promote the porous structure development of adsorbents, and the optimum preparation conditions were pyrolysis temperature 750°C and mass ratio (activator/dried sludge) 0.5. In batch experiments, ferric-activated SBA showed a higher adsorption capacity for tetracycline than non-activated SBA, because the enhanced mesoporous structure favored the diffusion of tetracycline into the pores, the iron oxides and oxygen-containing functional groups in the adsorbents captured tetracycline by surface complexation. The results indicate that ferric activation is an effective approach for preparing adsorbents from biological sludge to remove tetracycline, providing a potential option for waste resource recovery. PMID:27038265

  17. Purification of Sardine Oil Using Adsorbent (Active Filter) of Scallop Shells, Carp Scales and Attapulgite

    Sugeng Heri Suseno; Yosephina M.J. Batafor; Nurjanah; Ayu Fitri Izaki

    2014-01-01

    Fish oil especially from sardine has contain great omega 3, but it needs purification because has poor quality. Fish oil purification can be done by using various types of adsorbents. One of them are scallop shells and carp scales. The purpose of this study is to choose the best type of active filter (adsorbent) to improve the quality of fish oil. Sardine oil is purified using an active filter (adsorbent) of carp scales, scallop shells and attapulgite. The result this study show that the best...

  18. Magnetic susceptibility of oxygen adsorbed on the surface of spherical and fibrous activated carbon.

    Kiyoshi Kawamura

    2009-02-01

    Full Text Available The magnetic susceptibilities of oxygen adsorbed on the surface of bead-shaped activated carbon and activated carbon fibers were evaluated as a function of temperature between 4.2 K and 300 K, and found to exhibit a sharp peak at around 50 K. This implies that the adsorbed oxygen molecules form an antiferromagnetic state. The relation between the susceptibility and the adsorbed mass suggest that the thickness of the adsorbed oxygen is thin enough to consider a two-dimensional structure for bead–shaped activated carbon and carbon fibers across the fiber axis but thick enough to regard it as three-dimensional along the fiber axis. The result is discussed with reference to the study on one-dimensional oxygen array.

  19. Adsorption capacities of activated carbons for geosmin and 2-methylisoborneol vary with activated carbon particle size: Effects of adsorbent and adsorbate characteristics.

    Matsui, Yoshihiko; Nakao, Soichi; Sakamoto, Asuka; Taniguchi, Takuma; Pan, Long; Matsushita, Taku; Shirasaki, Nobutaka

    2015-11-15

    The adsorption capacities of nine activated carbons for geosmin and 2-methylisoborneol (MIB) were evaluated. For some carbons, adsorption capacity substantially increased when carbon particle diameter was decreased from a few tens of micrometers to a few micrometers, whereas for other carbons, the increase of adsorption capacity was small for MIB and moderate for geosmin. An increase of adsorption capacity was observed for other hydrophobic adsorbates besides geosmin and MIB, but not for hydrophilic adsorbates. The parameter values of a shell adsorption model describing the increase of adsorption capacity were negatively correlated with the oxygen content of the carbon among other characteristics. Low oxygen content indicated low hydrophilicity. The increase of adsorption capacity was related to the hydrophobic properties of both adsorbates and activated carbons. For adsorptive removal of hydrophobic micropollutants such as geosmin, it is therefore recommended that less-hydrophilic activated carbons, such as coconut-shell-based carbons, be microground to a particle diameter of a few micrometers to enhance their equilibrium adsorption capacity. In contrast, adsorption by hydrophilic carbons or adsorption of hydrophilic adsorbates occur in the inner pores, and therefore adsorption capacity is unchanged by particle size reduction. PMID:26302219

  20. Use of cyclic voltammetry and electrochemical impedance spectroscopy for determination of active surface area of modified carbon-based electrodes

    Carbon-based electrodes as well the ion exchange electrodes among others have been applied mainly in the treatment of industrial effluents and radioactive wastes. Carbon is also used in fuel cells as substrate for the electrocatalysts, having high surface area which surpasses its geometric area. The knowledge of the total active area is important for the determination of operating conditions of an electrochemical cell with respect to the currents to be applied (current density). In this study it was used two techniques to determine the electrochemical active surface area of glassy carbon, electrodes and ion exchange electrodes: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The experiments were carried out with KNO3 0.1 mol.L-1 solutions in a three-electrode electrochemical cell: carbon-based working electrode, platinum auxiliary electrode and Ag/AgCl reference electrode. The glassy carbon and porous carbon electrodes with geometric areas of 3.14 x 10-2 and 2.83 X 10-1 cm2, respectively, were used. The ion exchange electrode was prepared by mixing graphite, carbon, ion exchange resin and a binder, and this mixture was applied in three layers on carbon felt, using a geometric area of 1.0 cm2 during the experiments. The capacitance (Cd) of the materials was determined by EIS using Bode diagrams. The value of 172 μF.cm-2 found for the glassy carbon is consistent with the literature data (∼ 200 μF.cm'-2). By VC, varying the scan rate from 0.2 to 2.0 mV.s-1, the capacitance CdS (S = active surface area) in the region of the electric double layer (EDL) of each material was determined. By EIS, the values of Cd, 3.0 x 10-5 μF.cm'-2 and 11 x 103 μF.cm-2, were found for the porous carbon and ion exchange electrodes, respectively, which allowed the determination of active surface areas as 3.73 x 106 cm2 and 4.72 cm2. To sum up, the combined use of EIS and CV techniques is a valuable tool for the calculation of active surface areas of carbon-based

  1. Melatonin Nanoparticles Adsorbed to Polyethylene Glycol Microspheres as Activators of Human Colostrum Macrophages

    The effectiveness of hormones associated with polymeric matrices has amplified the possibility of obtaining new drugs to activate the immune system. Melatonin has been reported as an important immunomodulatory agent that can improve many cell activation processes. It is possible that the association of melatonin with polymers could influence its effects on cellular function. Thus, this study verified the adsorption of the hormone melatonin to polyethylene glycol (PEG) microspheres and analyzed its ability to modulate the functional activity of human colostrum phagocytes. Fluorescence microscopy and flow cytometry analyses revealed that melatonin was able to adsorb to the PEG microspheres. This system increased the release of superoxide and intracellular calcium. There was an increase of phagocytic and microbicidal activity by colostrum phagocytes when in the presence of melatonin adsorbed to PEG microspheres. The modified delivery of melatonin adsorbed to PEG microspheres may be an additional mechanism for its microbicidal activity and represents an important potential treatment for gastrointestinal infections of newborns.

  2. Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, (1)

    An investigation was carried out on the desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent by the batch process. The rate of desorption of uranium with acidic eluent depended on temperature, showing an increase as the temperature was raised. But the rate of desorption with acidic eluent was less dependent on temperature than that obtained when mixed eluent of sodium carbonate-sodium hydrogencarbonate was used. The difference of the rate of desorption of uranium in the range of concentration from 0.3 to 0.5N was not found, and the rate of desorption with sulfuric acid was slightly higher than that obtained when hydrochloric acid was used. The amount of dissolved titanium decreased as the ratio of adsorbent to eluent (RAE) was increased. At RAE of 10%, the percentage of dissolved titanium (DTI) was below 0.38% with sulfuric acid, below 0.7% with hydrochloric acid. These values were found to be higher than the ones with the carbonate eluent. The elements except uranium, which were adsorbed on the adsorbent, were eluted simultaneously with acidic eluent. The regeneration of the adsorbent after desorption, therefore, was found to be unnecessary. In a repeated test of adsorption-desorption treatment up to five times, the percentage of uranium adsorbed from natural sea water was approximately constant of 85%. From these results, the application of column process to the desorption of uranium with acidic eluent at room temperature was proposed to be feasible. (author)

  3. 2-chlorophenol sorption from aqueous solution using granular activated carbon and polymeric adsorbents

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

    2013-08-01

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

  4. Charcoal and activated carbon as adsorbate of phytotoxic compounds - a comparative study.

    Hille, M.G.; Ouden, den J.

    2005-01-01

    This study compares the potential of natural charcoal from Scots pine (Pinus sylvestris L.) and activated carbon to improve germination under the hypothesis that natural charcoal adsorbs phytotoxins produced by dwarf-shrubs, but due to it's chemical properties to a lesser extent than activated carbo

  5. Nomex-derived activated carbon fibers as electrode materials in carbon based supercapacitors

    Leitner, K.; Lerf, A.; Winter, M.; Besenhard, J. O.; Villar-Rodil, S.; Suárez-García, F.; Martínez-Alonso, A.; Tascón, J. M. D.

    Electrochemical characterization has been carried out for electrodes prepared of several activated carbon fiber samples derived from poly (m-phenylene isophthalamide) (Nomex) in an aqueous solution. Depending on the burn-off due to activation the BET surface area of the carbons was in the order of 1300-2800 m 2 g -1, providing an extensive network of micropores. Their capability as active material for supercapacitors was evaluated by using cyclic voltammetry and impedance spectroscopy. Values for the capacitance of 175 F g -1 in sulfuric acid were obtained. Further on, it was observed that the specific capacitance and the performance of the electrode increase significantly with increasing burn-off degree. We believe that this fact can be attributed to the increase of surface area and porosity with increasing burn-off.

  6. Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment

    Visa, Maria, E-mail: maria.visa@unitbv.ro [Transilvania University of Brasov, Department Renewable Energy Systems and Recycling, Eroilor 29, 500036 Brasov (Romania)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The spent adsorbent annealed at 500 Degree-Sign C can be a suggestion for padding in stone blocks. Black-Right-Pointing-Pointer The cations can be adsorbent by the silanol group (Si-OH) of the layers from bentonite Black-Right-Pointing-Pointer Copper has a higher affinity for the active sites on adsorbent FAw + B than cadmium. Black-Right-Pointing-Pointer This substrate can be recommended for simultaneous removal of heavy metals and MB. Black-Right-Pointing-Pointer FAw + B is recommended for wastewater treatment resulted in the dyes finishing industry. - Abstract: Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500 Degree-Sign C can be reused for padding in stone blocks.

  7. Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment

    Highlights: ► The spent adsorbent annealed at 500 °C can be a suggestion for padding in stone blocks. ► The cations can be adsorbent by the silanol group (Si-OH) of the layers from bentonite ► Copper has a higher affinity for the active sites on adsorbent FAw + B than cadmium. ► This substrate can be recommended for simultaneous removal of heavy metals and MB. ► FAw + B is recommended for wastewater treatment resulted in the dyes finishing industry. - Abstract: Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500 °C can be reused for padding in stone blocks.

  8. Efficiency of moso bamboo charcoal and activated carbon for adsorbing radioactive iodine

    Chien, Chuan-Chi; Huang, Ying-Pin; Wang, Wie-Chieh [ITRI South, Industrial Technology Research Institute, Tainan (China); Chao, Jun-Hsing; Wei, Yuan-Yao [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu (China)

    2011-02-15

    Preventing radioactive pollution is a troublesome problem but an urgent concern worldwide because radioactive substances cause serious health-related hazards to human being. The adsorption method has been used for many years to concentrate and remove radioactive pollutants; selecting an adequate adsorbent is the key to the success of an adsorption-based pollution abatement system. In Taiwan, all nuclear power plants use activated carbon as the adsorbent to treat radiation-contaminated air emission. The activated carbon is entirely imported; its price and manufacturing technology are entirely controlled by international companies. Taiwan is rich in bamboo, which is one of the raw materials for high-quality activated carbon. Thus, a less costly activated carbon with the same or even better adsorptive capability as the imported adsorbent can be made from bamboo. The objective of this research is to confirm the adsorptive characteristics and efficiency of the activated carbon made of Taiwan native bamboo for removing {sup 131}I gas from air in the laboratory. The study was conducted using new activated carbon module assembled for treating {sup 131}I-contaminated air. The laboratory results reveal that the {sup 131}I removal efficiency for a single-pass module is as high as 70%, and the overall efficiency is 100% for four single-pass modules operated in series. The bamboo charcoal and bamboo activated carbon have suitable functional groups for adsorbing {sup 131}I and they have greater adsorption capacities than commercial activated carbons. Main mechanism is for trapping of radioiodine on impregnated charcoal, as a result of surface oxidation. When volatile radioiodine is trapped by potassium iodide-impregnated bamboo charcoal, the iodo-compound is first adsorbed on the charcoal surface, and then migrates to iodide ion sites where isotope exchange occurs. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Visualization and Measurement of Adsorption/Desorption Process of Ethanol in Activated Carbon Adsorber

    Asano, Hitoshi; Murata, Kenta; Takenaka, Nobuyuki; Saito, Yasushi

    Adsorption refrigerator is one of the efficient tools for waste heat recovery, because the system is driven by heat at relative low temperature. However, the coefficient of performance is low due to its batch operation and the heat capacity of the adsorber. In order to improve the performance, it is important to optimize the configuration to minimize the amount of driving heat, and to clarify adsorption/desorption phenomena in transient conditions. Neutron radiography was applied to visualize and measure the adsorption amount distribution in an adsorber. The visualization experiments had been performed at the neutron radiography facility of E-2 port of Kyoto University Research Reactor. Activated carbon and ethanol were used as the adsorbent and refrigerant. From the acquired radiographs, adsorption amount was quantitatively measured by applying the umbra method using a checkered neutron absorber with boron powder. Then, transient adsorption and desorption processes of a rectangular adsorber with 84 mm in width, 50 mm in height and 20 mm in depth were visualized. As the result, the effect of fins in the adsorbent layer on the adsorption amount distribution was clearly visualized.

  10. Effect of conductive additives to gel electrolytes on activated carbon-based supercapacitors

    Farshad Barzegar

    2015-09-01

    Full Text Available This article is focused on polymer based gel electrolyte due to the fact that polymers are cheap and can be used to achieve extended potential window for improved energy density of the supercapacitor devices when compared to aqueous electrolytes. Electrochemical characterization of a symmetric supercapacitor devices based on activated carbon in different polyvinyl alcohol (PVA based gel electrolytes was carried out. The device exhibited a maximum energy density of 24 Wh kg−1 when carbon black was added to the gel electrolyte as conductive additive. The good energy density was correlated with the improved conductivity of the electrolyte medium which is favorable for fast ion transport in this relatively viscous environment. Most importantly, the device remained stable with no capacitance lost after 10,000 cycles.

  11. Active metal brazing of titanium to high-conductivity carbon-based sandwich structures

    Reactive brazing technology was developed and processing parameters were optimized for the bonding of titanium tubes, graphite foam, and high-conductivity carbon-carbon composite face sheets using the active braze Cusil-ABA paste and foils. The microstructure and composition of the joints, examined using scanning electron microscopy coupled with energy-dispersive spectroscopy, showed good bonding and braze penetration in all systems when braze paste was used. The hardness values of the brazed joints were consistent for the different specimen stacking configurations. Mechanical testing of Ti tube/foam/C-C composite structures both in tension and shear showed that failure always occurred in the foam material demonstrating that the brazed joint was sufficient for these types of sandwich structures

  12. Reductive dehalogenation of disinfection byproducts by an activated carbon-based electrode system.

    Li, Yuanqing; Kemper, Jerome M; Datuin, Gwen; Akey, Ann; Mitch, William A; Luthy, Richard G

    2016-07-01

    Low molecular weight, uncharged, halogenated disinfection byproducts (DBPs) are poorly removed by the reverse osmosis and advanced oxidation process treatment units often applied for further treatment of municipal wastewater for potable reuse. Granular activated carbon (GAC) treatment effectively sorbed 22 halogenated DBPs. Conversion of the GAC to a cathode within an electrolysis cell resulted in significant degradation of the 22 halogenated DBPs by reductive electrolysis at -1 V vs. Standard Hydrogen Electrode (SHE). The lowest removal efficiency over 6 h electrolysis was for trichloromethane (chloroform; 47%) but removal efficiencies were >90% for 13 of the 22 DBPs. In all cases, DBP degradation was higher than in electrolysis-free controls, and degradation was verified by the production of halides as reduction products. Activated carbons and charcoal were more effective than graphite for electrolysis, with graphite featuring poor sorption for the DBPs. A subset of halogenated DBPs (e.g., haloacetonitriles, chloropicrin) were degraded upon sorption to the GAC, even without electrolysis. Using chloropicrin as a model, experiments indicated that this loss was attributable to the partial reduction of sorbed chloropicrin from reducing equivalents in the GAC. Reducing equivalents depleted by these reactions could be restored when the GAC was treated by reductive electrolysis. GAC treatment of an advanced treatment train effluent for potable reuse effectively reduced the concentrations of chloroform, bromodichloromethane and dichloroacetonitrile measured in the column influent to below the method detection limits. Treatment of the GAC by reductive electrolysis at -1 V vs. SHE over 12 h resulted in significant degradation of the chloroform (63%), bromodichloromethane (96%) and dichloroacetonitrile (99%) accumulated on the GAC. The results suggest that DBPs in advanced treatment train effluents could be captured and degraded continuously by reductive electrolysis

  13. Preparation of Ammonia Adsorbent by Carbonizing and Activating Mixture of Biomass Material and Hygroscopic Salt

    LONG Zhen; BU Xianbiao; LU Zhenneng; LI Huashan; MA Weibin

    2015-01-01

    We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of CaCl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power (SCP) at 5 min adsorption time can reach as high as 0.19 g•g-1 and 793.9 W•kg-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.

  14. Activated carbon is an electron-conducting amphoteric ion adsorbent

    Biesheuvel, P. M.

    2015-01-01

    Electrodes composed of activated carbon (AC) particles can desalinate water by ion electrosorption. To describe ion electrosorption mathematically, accurate models are required for the structure of the electrical double layers (EDLs) that form within electrically charged AC micropores. To account for salt adsorption also in uncharged ACs, an "attraction term" was introduced in modified Donnan models for the EDL structure in ACs. Here it will be shown how instead of using an attraction term, c...

  15. Granular activated carbon based microbial fuel cell for simultaneous decolorization of real dye wastewater and electricity generation.

    Kalathil, Shafeer; Lee, Jintae; Cho, Moo Hwan

    2011-12-15

    Decolorization of dye wastewater before discharge is pivotal because of its immense color and toxicities. In this study, a granular activated carbon based microbial fuel cell (GACB-MFC) was used without using any expensive materials like Nafion membrane and platinum catalyst for simultaneous decolorization of real dye wastewater and bioelectricity generation. After 48 hours of GACB-MFC operation, 73% color was removed at anode and 77% color was removed at cathode. COD removal was 71% at the anode and 76% at the cathode after 48 hours. Toxicity measurements showed that cathode effluent was almost nontoxic after 24 hours. The anode effluent was threefold less toxic compared to original dye wastewater after 48 hours. The GACB-MFC produced a power density of 1.7 W/m(3) with an open circuit voltage 0.45 V. One of the advantages of the GACB-MFC system is that pH was automatically adjusted from 12.4 to 7.2 and 8.0 at the anode and cathode during 48 hours operation. PMID:21718812

  16. Activated carbon is an electron-conducting amphoteric ion adsorbent

    Biesheuvel, P M

    2015-01-01

    Electrodes composed of activated carbon (AC) particles can desalinate water by ion electrosorption. To describe ion electrosorption mathematically, accurate models are required for the structure of the electrical double layers (EDLs) that form within electrically charged AC micropores. To account for salt adsorption also in uncharged ACs, an "attraction term" was introduced in modified Donnan models for the EDL structure in ACs. Here it will be shown how instead of using an attraction term, chemical information of the surface structure of the carbon-water interface in ACs can be used to construct an alternative EDL model for ACs. This EDL model assumes that ACs contain both acidic groups, for instance due to carboxylic functionalities, and basic groups, due to the adsorption of protons to the carbon basal planes. As will be shown, this "amphoteric Donnan" model accurately describes various data sets for ion electrosorption in ACs, for solutions of NaCl, of CaCl2, and mixtures thereof, as function of the exter...

  17. Alumina-Activated Carbon Composite as Adsorbent of Procion Red Dye from Wastewater Songket Industry

    Poedji Loekitowati Hariani; Fatma Fatma; Zulfikar Zulfikar

    2015-01-01

    Alumina-activated carbon composite has been synthesized and studied for adsorption procion red dye. Composite was prepared by precipitation method aluminium hydroxide on the surface of activated carbon followed by calcinations. The Fourier transform Infra Red (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) and Brunaeur Emmet Teller (BET) surface are being used to characterize the adsorbent. Batch adsorption experiments were carried out for the adsorption of...

  18. A Photocatalytic Active Adsorbent for Gas Cleaning in a Fixed Bed Reactor

    Peter Pucher

    2008-01-01

    Full Text Available Efficient photocatalysis for gas cleaning purposes requires a large accessible, illuminated active surface in a simple and compact reactor. Conventional concepts use powdered catalysts, which are nontransparent. Hence a uniform distribution of light is difficult to be attained. Our approach is based on a coarse granular, UV-A light transparent, and highly porous adsorbent that can be used in a simple fixed bed reactor. A novel sol-gel process with rapid micro mixing is used to coat a porous silica substrate with TiO2-based nanoparticles. The resulting material posses a high adsorption capacity and a photocatalytic activity under UV-A illumination (PCAA = photocatalytic active adsorbent. Its photocatalytic performance was studied on the oxidation of trichloroethylene (TCE in a fixed bed reactor setup in continuous and discontinuous operation modes. Continuous operation resulted in a higher conversion rate due to less slip while discontinuous operation is superior for a total oxidation to CO2 due to a user-defined longer residence time.

  19. Ceria modified activated carbon: an efficient arsenic removal adsorbent for drinking water purification

    Sawana, Radha; Somasundar, Yogesh; Iyer, Venkatesh Shankar; Baruwati, Babita

    2016-03-01

    Ceria (CeO2) coated powdered activated carbon was synthesized by a single step chemical process and demonstrated to be a highly efficient adsorbent for the removal of both As(III) and As(V) from water without any pre-oxidation process. The formation of CeO2 on the surface of powdered activated carbon was confirmed by X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The percentage of Ce in the adsorbent was confirmed to be 3.5 % by ICP-OES. The maximum removal capacity for As(III) and As(V) was found to be 10.3 and 12.2 mg/g, respectively. These values are comparable to most of the commercially available adsorbents. 80 % of the removal process was completed within 15 min of contact time in a batch process. More than 95 % removal of both As(III) and As(V) was achieved within an hour. The efficiency of removal was not affected by change in pH (5-9), salinity, hardness, organic (1-4 ppm of humic acid) and inorganic anions (sulphate, nitrate, chloride, bicarbonate and fluoride) excluding phosphate. Presence of 100 ppm phosphate reduced the removal significantly from 90 to 18 %. The equilibrium adsorption pattern of both As(III) and As(V) fitted well with the Freundlich model with R 2 values 0.99 and 0.97, respectively. The material shows reusability greater than three times in a batch process (arsenic concentration reduced below 10 ppb from 330 ppb) and a life of at least 100 L in a column study with 80 g material when tested under natural hard water (TDS 1000 ppm, pH 7.8, hardness 600 ppm as CaCO3) spiked with 330 ppb of arsenic.

  20. Experimental study on solar-powered adsorption refrigeration cycle with activated alumina and activated carbon as adsorbent

    Himsar Ambarita

    2016-03-01

    Full Text Available Typical adsorbent applied in solar-powered adsorption refrigeration cycle is activated carbon. It is known that activated alumina shows a higher adsorption capacity when it is tested in the laboratory using a constant radiation heat flux. In this study, solar-powered adsorption refrigeration cycle with generator filled by different adsorbents has been tested by exposing to solar radiation in Medan city of Indonesia. The generator is heated using a flat-plate type solar collector with a dimension of 0.5 m×0.5 m. Four cases experiments of solar-powered adsorption cycle were carried out, they are with generator filled by 100% activated alumina (named as 100AA, by a mixed of 75% activated alumina and 25% activated carbon (75AA, by a mixed of 25% activated alumina and 75% activated carbon (25AA, and filled by 100% activated carbon. Each case was tested for three days. The temperature and pressure history and the performance have been presented and analyzed. The results show that the average COP of 100AA, 75AA, 25AA, and 100AC is 0.054, 0.056, 0.06, and 0.074, respectively. The main conclusion can be drawn is that for Indonesian condition and flat-plate type solar collector the pair of activated carbon and methanol is the better than activated alumina.

  1. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

    Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

    2012-05-01

    Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

  2. Preparation of Fly ash Based Adsorbents for Removal Active Red X-3B from Dying Wastewater

    Li Jinping

    2016-01-01

    Full Text Available Fly ash with a large number of active sites can occur with the adsorbent chemical and physical adsorption, and therefore have a strong adsorption capacity. The original fly ash and raw fly ash compared to the physical and chemical properties to a significant change. On the fly ash in industrial water treatment application were outlined. The purpose is to focus on the modification methods of fly ash and comparison of raw fly ash and fly ash in the effect of dyeing wastewater. Single factor test method; select the appropriate modifier to study the dosage, pH, stirring time on the modification of adsorption properties of fly ash before and after. The results showed that the modified fly ash was better than the adsorption. Greatly improves on active red X-3B dye wastewater removal capacity, pH = 5, 6, dosage is 5g / L, the mixing time is 30min, COD removal rate reached 73.07%. This modified material can be used as adsorbent for pre-treating dying wastewater.

  3. Developing almond shell-derived activated carbons as CO{sub 2} adsorbents

    Plaza, M.G.; Pevida, C.; Martin, C.F.; Fermoso, J.; Pis, J.J.; Rubiera, F. [CSIC, Oviedo (Spain)

    2010-01-29

    Two series of carbon dioxide adsorbents were prepared from almond shells, by carbonisation followed either by activation with CO{sub 2} or by heat treatment in the presence of ammonia gas (amination). Both procedures gave carbons with high CO{sub 2} adsorption capacities in pure CO{sub 2} as well as in a binary mixture of 15% CO{sub 2} in N{sub 2}. Activation with carbon dioxide significantly developed porosity in the samples, mostly in the micropore domain, while amination at 800{sup o}C moderately developed narrow microporosity in the char and incorporated stable nitrogen functionalities, which enhanced CO{sub 2} selectivity. Amination showed two additional advantages over conventional activation with CO{sub 2}: a greater carbon yield and a shorter soaking time.

  4. Electrocatalytic activity of surface adsorbed ruthenium-alizarin complexone toward the oxidation of benzyl alcohol

    The surface electrochemical behavior of an adsorbed alizarin complexone (abbreviated as AC) and its surface coordination with Ru(II) were studied in aqueous solution at a pH range of 0-6. The surface complex of ruthenium with AC displays strong electrocatalytic activities toward benzyl alcohol. Based on the rotating disk electrode measurement, it is believed that the electrocatalytic oxidation of benzyl alcohol is a two-electron and two-proton process with benzaldehyde as a major product. On the other hand, ruthenium-AC surface complex has also shown catalytic activities toward electro-oxidation of several small organic molecules such as methanol, formic acid, formaldehyde, ethanol, and acetaldehyde

  5. Comparative SPR study on the effect of nanomaterials on the biological activity of adsorbed proteins

    Bioactivity of proteins is evaluated to test the adverse effects of nanoparticles interjected into biological systems. Surface plasmon resonance (SPR) spectroscopy detects binding affinity that is normally related to biological activity. Utilizing SPR spectroscopy, a concise testing matrix is established by investigating the adsorption level of bovine serum albumin (BSA) and anti-BSA on the surface covered with 11-mercaptoundecanoic acid (MUA); magnetic nanoparticles (MNPs) and single-walled carbon nanotubes (SWCNTs), respectively. The immunoactivity of BSA on MNPs and SWCNT decreased by 18 % and 5 %, respectively, compared to that on the gold film modified with MUA. This indicates that MNPs cause a considerable loss of biological activity of adsorbed protein. This effect can be utilized for practical applications on detailed biophysical research and nanotoxicity studies. (author)

  6. Development of Activated Carbon from Cotton Fibre Waste as Potential Mercury Adsorbent: Kinetic and Equilibrium Studies

    Jatindra N. Bhakta

    2014-01-01

    Full Text Available The study attempted to develop the activated carbon of cotton fibre (ACCF from cotton waste as a high Hg2+ adsorbent media and characterize physicochemical properties using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS and Hg2+ adsorption kinetic by batch adsorption study with the function of contact time, solution pH, dosages of ACCF, and Hg concentration. The SEM-EDS study revealed that ACCF is composed of carbon (95.1% and phosphorus pentoxide (4.9%. Obtained results of adsorption kinetics showed that 15 min of contact time is required to achieve the equilibrium state and wide range of pH (4.08–7 is favourable for maximum Hg adsorption. The Hg2+ adsorption capacity showed a decreasing trend with increasing dose of ACCF, whereas a reverse response of adsorption capacity was pronounced with increasing Hg concentration. The data was well described by Freundlich isotherm model and determined the high Hg2+ adsorption capacity of ACCF (169.2 mg/g. To our knowledge, the application of ACCF in removing Hg2+ is the first study. High Hg2+ adsorption capacity, economic feasibility, availability of cotton fibre waste, and simple preparation method concluded that it could be used as a novel low-cost and environmentally sound adsorbent media for removing high rate of Hg2+ from aqueous phase.

  7. Production of graphitic carbon-based nanocomposites from K2CO3-activated coconut shells as counter electrodes for dye-sensitized solar-cell applications

    Loryuenyong, Vorrada; Buasri, Achanai; Lerdvilainarit, Parichat; Manachevakulm, Konnatee; Sompong, Siripond

    2016-01-01

    In this study, graphitic carbon-activated carbon nanocomposites fabricated from K2CO3 chemically-activated coconut shells by using Fe-catalytic chemical vapor deposition are reported. The present method was simple, environmentally-friendly, low cost, but successfully offered graphitic carbon-based materials that demonstrated promise for use as counter electrodes in dye-sensitized solar cells. The results showed that the coconut shell:catalyst ratio (1:0, 1:4, 1:1, and 4:1) significantly affected the structural, physical and electrochemical properties of the samples. Graphitic carbon and activated carbon nanocomposites with a high specific surface area of 1230 m2/g and high electrochemical activity in iodide reduction are obtained for samples with a coconut shells/iron precursor (Fe(NO3)3) ratio of 4:1.

  8. Performance of magnetic activated carbon composite as peroxymonosulfate activator and regenerable adsorbent via sulfate radical-mediated oxidation processes.

    Oh, Wen-Da; Lua, Shun-Kuang; Dong, Zhili; Lim, Teik-Thye

    2015-03-01

    Magnetic activated carbon composite (CuFe2O4/AC, MACC) was prepared by a co-precipitation-calcination method. The MACC consisted of porous micro-particle morphology with homogeneously distributed CuFe2O4 and possessed high magnetic saturation moment (8.1 emu g(-1)). The performance of MACC was evaluated as catalyst and regenerable adsorbent via peroxymonosulfate (PMS, Oxone(®)) activation for methylene blue (MB) removal. Optimum CuFe2O4/AC w/w ratio was 1:1.5 giving excellent performance and can be reused for at least 3 cycles. The presence of common inorganic ions, namely Cl(-) and NO3(-) did not exert significant influence on MB degradation but humic acid decreased the MB degradation rate. As a regenerable adsorbent, negligible difference in regeneration efficiency was observed when a higher Oxone(®) dosage was employed but a better efficiency was obtained at a lower MACC loading. The factors hindering complete MACC regeneration are MB adsorption irreversibility and AC surface modification by PMS making it less favorable for subsequent MB adsorption. With an additional mild heat treatment (150 °C) after regeneration, 82% of the active sites were successfully regenerated. A kinetic model incorporating simultaneous first-order desorption, second-order adsorption and pseudo-first order degradation processes was numerically-solved to describe the rate of regeneration. The regeneration rate increased linearly with increasing Oxone(®):MACC ratio. The MACC could potentially serve as a catalyst for PMS activation and regenerable adsorbent. PMID:25463211

  9. Alumina-Activated Carbon Composite as Adsorbent of Procion Red Dye from Wastewater Songket Industry

    Poedji Loekitowati Hariani

    2015-03-01

    Full Text Available Alumina-activated carbon composite has been synthesized and studied for adsorption procion red dye. Composite was prepared by precipitation method aluminium hydroxide on the surface of activated carbon followed by calcinations. The Fourier transform Infra Red (FTIR, Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS and Brunaeur Emmet Teller (BET surface are being used to characterize the adsorbent. Batch adsorption experiments were carried out for the adsorption of procion red dye. Effect of the mass of composite, stirrer speed, contact times and pH of the solution on the adsorption capacity were studied. The obtained optimum conditions applied to adsorp of procion red dye from wastewater songket industry. The result showed that the adsorption optimum at mass of alumina-activated carbon composite 0.1 g, stirrer speed 150 rpm, contact times 2 hours at pH of the solution 9. The adsorption isotherm data according to Langmuir isotherm. The alumina-activated carbon composite can be removal of procion red dye from wastewater songket industry with effectiveness adsorption of 88.21 %.

  10. The effects of adsorbing organic pollutants from super heavy oil wastewater by lignite activated coke.

    Tong, Kun; Lin, Aiguo; Ji, Guodong; Wang, Dong; Wang, Xinghui

    2016-05-01

    The adsorption of organic pollutants from super heavy oil wastewater (SHOW) by lignite activated coke (LAC) was investigated. Specifically, the effects of LAC adsorption on pH, BOD5/COD(Cr)(B/C), and the main pollutants before and after adsorption were examined. The removed organic pollutants were characterized by Fourier transform infrared spectroscopy (FTIR), Boehm titrations, gas chromatography-mass spectrometry (GC-MS), and liquid chromatography with organic carbon detection (LC-OCD). FTIR spectra indicated that organic pollutants containing -COOH and -NH2 functional groups were adsorbed from the SHOW. Boehm titrations further demonstrated that carboxyl, phenolic hydroxyl, and lactonic groups on the surface of the LAC increased. GC-MS showed that the removed main organic compounds are difficult to be degraded or extremely toxics to aquatic organisms. According to the results of LC-OCD, 30.37 mg/L of dissolved organic carbons were removed by LAC adsorption. Among these, hydrophobic organic contaminants accounted for 25.03 mg/L. Furthermore, LAC adsorption was found to increase pH and B/C ratio of the SHOW. The mechanisms of adsorption were found to involve between the hydrogen bonding and the functional groups of carboxylic, phenolic, and lactonic on the LAC surface. In summary, all these results demonstrated that LAC adsorption can remove bio-refractory DOCs, which is beneficial for biodegradation. PMID:26808249

  11. Porous Carbon Based Solid Adsorbents for Carbon Dioxide Capture

    Travis, W.

    2015-01-01

    The aim of this project is the design, synthesis and characterisation of porous carbon structures capable of the selective capture of carbon dioxide (CO2) from the exhaust gases of coal and gas post-combustion power stations. In such systems, the fossil fuel is burnt in an air environment producing CO2 as just one of a multi-component flue gas. This flue gas is expected to contain nitrogen and water among other constituents. It is at ambient pressures and temperatures of ≥323 K. Successful ca...

  12. Non-equilibrium Transport in Carbon based Adsorbate Systems

    Fürst, Joachim; Brandbyge, Mads; Stokbro, Kurt; Jauho, Antti-Pekka

    2007-03-01

    We have used the Atomistix Tool Kit(ATK) and TranSIESTA[1] packages to investigate adsorption of iron atoms on a graphene sheet. The technique of both codes is based on density functional theory using local basis sets[2], and non-equilibrium Green's functions (NEGF) to calculate the charge distribution under external bias. Spin dependent electronic structure calculations are performed for different iron coverages. These reveal adsorption site dependent charge transfer from iron to graphene leading to screening effects. Transport calculations show spin dependent scattering of the transmission which is analysed obtaining the transmission eigenchannels for each spin type. The phenomena of electromigration of iron in these systems at finite bias will be discussed, estimating the so-called wind force from the reflection[3]. [1] M. Brandbyge, J.-L. Mozos, P. Ordejon, J. Taylor, and K. Stokbro. Physical Review B (Condensed Matter and Materials Physics), 65(16):165401/11-7, 2002. [2] Jose M. Soler, Emilio Artacho, Julian D. Gale, Alberto Garcia, Javier Junquera, Pablo Ordejon, and Daniel Sanchez-Portal. Journal of Physics Condensed Matter, 14(11):2745-2779, 2002. [3] Sorbello. Theory of electromigration. Solid State Physics, 1997.

  13. A comparative study of carbon felt and activated carbon based electrodes for sodium polysulfide/bromine redox flow battery

    Carbon felt (CF) and activated carbon (AC) based electrodes for sodium polysulfide/bromine redox flow battery (PSB) were prepared and compared with a laboratory scale PSB flow cell in terms of structure and application performances. The structural properties of the two types of electrodes were characterized by filamentary analog and BET analysis, respectively. Catalyst coating, discharge behavior analysis and thermogravimetric analysis-mass spectrometry (TG-MS) were carried out to make out the different dominant factor in the application performances of the two materials. Compared to AC based electrode (ACE), despite of the relatively low surface area, CF demonstrates almost the same application performances, much more gains in electrochemical activity towards negative half-cell reactions by catalyst coating, and more even discharge voltage curve and stable cycling performance. At current density of 40 mA cm-2, an average energy efficiency of up to 81% over 50 cycles (about 600 h) has been achieved with cobalt coated CF, but with ACE only 64.7% within 16 cycles, which decreases quickly due to the loss of surface area resulted from sulfur depositing. The difference in structure related to mass transport makes the application performances gap between the two types of materials in PSB

  14. Strategies for enhancing electrochemical activity of carbon-based electrodes for all-vanadium redox flow batteries

    Highlights: ► Improved reactions at the positive electrode in all-vanadium redox flow batteries. ► Graphene-derived and PAN-modified electrodes have been successfully prepared. ► Modification with bimetallic CuPt3 nanocubes yielded the best catalytic behavior. ► N and O-containing groups enhances the vanadium flow battery performance. - Abstract: Two strategies for improving the electroactivity towards VO2+/VO2+ redox pair, the limiting process in all-vanadium redox flow batteries (VFBs), were presented. CuPt3 nanoparticles supported onto graphene substrate and nitrogen and oxygen polyacrylonitrile (PAN)-functionalized electrodes materials have been evaluated. The morphology, composition, electrochemical properties of all electrodes prepared was characterized with field emission-scanning electrode microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and cell charge–discharge test. The presence of the CuPt3 nanocubes and nitrogen and oxygen functionalities enhance the electrocatalytic activity of the electrodes materials accelerating the oxygen and electron transfer processes. The battery performance was also evaluated using PAN-functionalized electrodes exhibiting a high of energy efficiency of 84% (at current density 20 mA cm−2) up to 30th cycle, indicating a promising alternative for improving the VFB

  15. Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment

    Visa, Maria

    2012-12-01

    Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500 °C can be reused for padding in stone blocks.

  16. Microwave-assisted activated carbon from cocoa shell as adsorbent for removal of sodium diclofenac and nimesulide from aqueous effluents

    Highlights: • Microwave-assisted cocoa shell activated carbon was prepared and characterized. • The anti-inflammatories, diclofenac and nimesulide, were adsorbed onto MWCS-1.0. • Adsorption maximum values are 63.47 (diclofenac) and 74.81 mg g−1 (nimesulide). • General order kinetic model suitably explained the adsorption process. • MWCS-1.0 was effectively used for treatment of simulated hospital effluents. - Abstract: Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10 min. The CSC-1.0 was acidified with a 6 mol L−1 HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N2 adsorption/desorption curves, X-ray diffraction, and point of zero charge (pHpzc). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25 °C are 63.47 and 74.81 mg g−1, respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations

  17. Kinetics of the Removal of Chromium Complex Dye from Aqueous Solutions Using Activated Carbons and Polymeric Adsorbent

    Eglė Kazlauskienė

    2011-04-01

    Full Text Available The kinetics of the removal of chromium complex dye (Lanasyn Navy M-DNL from aqueous solutions using polymeric adsorbent Macronet MN 200 (MN 200 as an alternative option for activated carbon Norit RB 0.8 CC (AC was studied in the batch system. The residual colour of dye solution treated with AC or MN 200 strongly depends on solution pH with lower values at acidic pH when a positively charged surface net is favourable for the adsorption of the dye anion. The removal of dye using MN 200 was found relatively higher than that using AC. The pseudo-second order and intraparticle diffusion models agreed well with experimental data. The parameters of these models were studied as a function of temperature and adsorbent nature.Article in Lithuanian

  18. [Intraoperative chemotherapy with intraperitoneal activated carbon particles adsorbing mitomycin C against peritoneal dissemination of gastric cancer].

    Iwamoto, A; Takahashi, T; Sasabe, T; Itoh, M; Kondoh, S; Seiki, K; Yoneyama, C; Shimotsuma, M; Hagiwara, A; Yamaguchi, T

    1989-08-01

    A new form of dosage (MMC-CH) was composed of activated carbon particles adsorbing mitomycin C. Intraperitoneal administration of MMC-CH was tested clinically for prophylactic and therapeutic effects on peritoneal carcinomatosis of gastric cancer. The criteria of MMC-CH's administration were equal or less than 70 years old, more than 40 kg in body weight, no disfunction of liver and kidney, no particular findings in electrocardiography, S2 or S3 in the grade of serosal invasion, P0, P1, P2 or P3 in the grade of peritoneal dissemination, according to the General Rules for the Gastric Cancer Study in Surgery and Pathology by the Japanese Research Society for Gastric Cancer. MMC-CH was given to 44 patients undergoing gastrectomy for gastric cancer in our department from 1985 to 1988. The 44 patients were composed of 12 patients with P0 findings (P0 patients), 8 patients with P1 findings (P1 patients), 12 patients with P2 findings (P2 patients), and 12 patients with P3 findings (P3 patients). MMC-CH at 50 mg/person in terms of mitomycin C was administered intraperitoneally before the operation wound was closed. Fifty-seven patients in our department from 1983 to 1987 for whom the same criteria were applicable and did not receive MMC-CH therapy, served as the control group. The 57 patients were composed of 23 P0 patients, 21 P1 patients, 10 P2 patients, and 3 P3 patients. There was statistically with chi 2 test no significant difference of age, sex, depth of infiltration macroscopically and microscopically defined progression of lymph-nodal metastases between the MMC-CH group and the control group. Survival rate was calculated with Kaplan-Meier's method in the overall patients in each of the MMC-CH group or the control group. The overall survival rate in the MMC-CH group was statistically significantly (p less than 0.01-0.05) higher from day 460 to day 552 and from day 736 to day 800 than that in the control group. Next, the patients were classified into two subgroups

  19. Synthesis, Characterization, and Catalytic Activity of Sulfonated Carbon-Based Catalysts Derived From Rubber Tree Leaves and Pulp and Paper Mill Waste

    Janaun, J.; Sinin, E.; Hiew, S. F.; Kong, A. M. T.; Lahin, F. A.

    2016-06-01

    Sulfonated carbon-based catalysts derived from rubber tree leaves, and pulp and paper mill waste were synthesized and characterized. Three types of catalyst synthesized were sulfonated rubber tree leaves (S-RTL), pyrolysed sludge char (P-SC) and sulfonated sludge char (S-SC). Sulfonated rubber tree leaves (S-RTL) and sulfonated sludge char (S-SC) were prepared through pyrolysis followed by functionalization via sulfonation process whereas, P- SC was only pyrolyzed without sulfonation. The characterization results indicated sulfonic acids, hydroxyl, and carboxyl moieties were detected in S-RTL and S-SC, but no sulfonic acid was detected in P-SC. Total acidity test showed S-RTL had the highest value followed by S-SC and P-SC. The thermal stability of S-RTL and S-SC were up to 230oC as the loss was associated with the decomposition of sulfonic acid group, whereas, P-SC showed higher stability than the S-RTL and S-SC. Morphology analysis showed that S-RTL consisted of an amorphous carbon structure, and a crystalline structure for P-SC and S-SC. Furthermore, traces of metal components were also detected on all of the catalysts. The catalyst catalytic activity was tested through esterification of oleic acid with methanol. The results showed that the reaction using S-RTL catalyst produced the highest conversion (99.9%) followed by P-SC (88.4%) and lastly S-SC (82.7%). The synthesized catalysts showed high potential to be used in biodiesel production.

  20. Direct observation of solid-phase adsorbate concentration profile in powdered activated carbon particle to elucidate mechanism of high adsorption capacity on super-powdered activated carbon.

    Ando, Naoya; Matsui, Yoshihiko; Matsushita, Taku; Ohno, Koichi

    2011-01-01

    Decreasing the particle size of powdered activated carbon (PAC) by pulverization increases its adsorption capacities for natural organic matter (NOM) and polystyrene sulfonate (PSS, which is used as a model adsorbate). A shell adsorption mechanism in which NOM and PSS molecules do not completely penetrate the adsorbent particle and instead preferentially adsorb near the outer surface of the particle has been proposed as an explanation for this adsorption capacity increase. In this report, we present direct evidence to support the shell adsorption mechanism. PAC particles containing adsorbed PSS were sectioned with a focused ion beam, and the solid-phase PSS concentration profiles of the particle cross-sections were directly observed by means of field emission-scanning electron microscopy/energy-dispersive X-ray spectrometry (FE-SEM/EDXS). X-ray emission from sulfur, an index of PSS concentration, was higher in the shell region than in the inner region of the particles. The X-ray emission profile observed by EDXS did not agree completely with the solid-phase PSS concentration profile predicted by shell adsorption model analysis of the PSS isotherm data, but the observed and predicted profiles were not inconsistent when the analytical errors were considered. These EDXS results provide the first direct evidence that PSS is adsorbed mainly in the vicinity of the external surface of the PAC particles, and thus the results support the proposition that the increase in NOM and PSS adsorption capacity with decreasing particle size is due to the increase in external surface area on which the molecules can be adsorbed. PMID:20851447

  1. Kinetics of the Removal of Chromium Complex Dye from Aqueous Solutions Using Activated Carbons and Polymeric Adsorbent

    Eglė Kazlauskienė; Danutė Kaušpėdienė

    2011-01-01

    The kinetics of the removal of chromium complex dye (Lanasyn Navy M-DNL) from aqueous solutions using polymeric adsorbent Macronet MN 200 (MN 200) as an alternative option for activated carbon Norit RB 0.8 CC (AC) was studied in the batch system. The residual colour of dye solution treated with AC or MN 200 strongly depends on solution pH with lower values at acidic pH when a positively charged surface net is favourable for the adsorption of the dye anion. The removal of dye using MN 200 was ...

  2. Microwave-assisted activated carbon from cocoa shell as adsorbent for removal of sodium diclofenac and nimesulide from aqueous effluents

    Saucier, Caroline [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Adebayo, Matthew A. [Department of Chemical Sciences, Ajayi Crowther University, Oyo, Oyo State (Nigeria); Lima, Eder C., E-mail: eder.lima@ufrgs.br [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Cataluña, Renato [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Thue, Pascal S. [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Department of Applied Chemistry, University of Ngaoundere, P.O. Box 455, Ngaoundere (Cameroon); Prola, Lizie D.T.; Puchana-Rosero, M.J. [Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Machado, Fernando M. [Technology Development Center, Federal University of Pelotas (UFPEL), Pelotas (Brazil); Pavan, Flavio A. [Institute of Chemistry, Federal University of Pampa (UNIPAMPA), Bagé, RS (Brazil); Dotto, G.L. [Chemical Engineering Department, Federal University of Santa Maria (UFSM), Santa Maria, RS (Brazil)

    2015-05-30

    Highlights: • Microwave-assisted cocoa shell activated carbon was prepared and characterized. • The anti-inflammatories, diclofenac and nimesulide, were adsorbed onto MWCS-1.0. • Adsorption maximum values are 63.47 (diclofenac) and 74.81 mg g{sup −1} (nimesulide). • General order kinetic model suitably explained the adsorption process. • MWCS-1.0 was effectively used for treatment of simulated hospital effluents. - Abstract: Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10 min. The CSC-1.0 was acidified with a 6 mol L{sup −1} HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N{sub 2} adsorption/desorption curves, X-ray diffraction, and point of zero charge (pH{sub pzc}). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25 °C are 63.47 and 74.81 mg g{sup −1}, respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations.

  3. Activated carbons from flax shive and cotton gin waste as environmental adsorbents for the chlorinated hydrocarbon trichloroethylene.

    Klasson, K Thomas; Wartelle, Lynda H; Lima, Isabel M; Marshall, Wayne E; Akin, Danny E

    2009-11-01

    Agricultural by-products represent a considerable quantity of harvested commodity crops. The use of by-products as precursors for the production of widely used adsorbents, such as activated carbons, may impart a value-added component of the overall biomass harvested. Our objective in this paper is to show that flax shive and cotton gin waste can serve as a precursor for activated carbon that can be used for adsorption of trichloroethylene (TCE) from both the liquid and gas phases. Testing was conducted on carbon activated with phosphoric acid or steam. The results show that activated carbon made from flax shive performed better than select commercial activated carbons, especially at higher TCE concentrations. The activation method employed had little effect on TCE adsorption in gas or vapor phase studies but liquid phase studies suggested that steam activation is slightly better than phosphoric acid activation. As expected, the capacity for the activated carbons depended on the fluid phase equilibrium concentration. At a fluid concentration of 2 mg of TCE/L of fluid, the capacity of the steam activated carbon made from flax shive was similar at 64 and 80 mg TCE/g of carbon for the vapor and liquid phases, respectively. Preliminary cost estimates suggest that the production costs of such carbons are $1.50 to $8.90 per kg, depending on activation method and precursor material; steam activation was significantly less expensive than phosphoric acid activation. PMID:19540755

  4. ADSORPTION OF Cu(II FROM THE AQUEOUS SOLUTION BY CHEMICAL ACTIVATED ADSORBENT OF ARECA CATECHU SHELL

    MUSLIM A.

    2015-12-01

    Full Text Available Areca catechu shell (ACS was utilised as adsorbent for removal of Cu(II from aqueous solution. FTIR and SEM analysis were conducted to characterise the surface morphology of chemical activated ACS adsorbent. The ACS adsorbent has been investigated in terms of contact time and Cu(II initial concentration. As a result, the efficiency of Cu(II removal in solution exponentially increased with contact time reaching equilibrium at 9.6 ks. Cu (II adsorption capacity increased over the increasing Cu(II initial concentration in solution from 0 to 14 mg/L, and it decreased for the decreasing Cu(II initial concentration in solution from 14 to 25 mg/L. The highest Cu(II adsorption capacity for the Cu(II initial concentration being in the range of 1-25 mg/L was 1.33 mg/g at 14 mg/L Cu(II initial concentration. The kinetics study showed the Cu(II adsorption kinetics followed the pseudo-second-order kinetics with the correlation coefficients (R2 being 0.999 and the rate constant, kH being 0.18 g/mg.ks. Meanwhile, the pseudo-first-order rate constant, kL being 0.52 /ks with the R2 being 0.807. Moreover, the Cu(II adsorption isotherm followed the Langmuir model with the R2 being 0.98, and the mono-layer adsorption capacity being approximately 0.964 mg/g. The Langmuir over-all adsorption capacity is approximately 2.788 L/mg.

  5. Preparation of potassium iron(III) hexacyanoferrate(II) supported on activated carbon and Cs uptake performance of the adsorbent

    Synthesis of potassium iron(III) hexacyanoferrate(II) (K/Fe-Fe(CN)6) in the pores of activated carbon (AC) was attempted by impregnating AC with K4[Fe(CN)6] and FeCl3, and the Cs uptake performance of the resulting adsorbent was examined. K/Fe-Fe(CN)6 supported on AC was prepared by varying the reaction conditions such as the supplied amounts and molar ratios of the reagents, and the Cs uptake performance was optimized. The impregnated product was characterized by XRD, EPMA, and porosimetry to elucidate the condition to which Fe4[Fe(CN)6]3 was filled in the AC pores. The K/Fe-Fe(CN)6-on-AC was immersed in seawater containing 0.075 mmol·dm-3 Cs and agitated for 1 day to obtain the Cs uptake. The Cs uptake was large at pH 10.5. The maximum Cs uptake was 10.4 μmol·g-1 at the equilibrium Cs concentration of 49 μmol·dm-3 and the distribution coefficient was 45.5 dm3·g-1 at the equilibrium concentration of 0.015 μmol·dm-3, respectively. When K/Fe-Fe(CN)6-on-AC was immersed in Cs-containing seawater, K+ ions in the adsorbent were completely exchanged for Na+ ions in seawater, and the added Cs+ ions were then substituted for the Na+ ions in the adsorbent. (author)

  6. Radon adsorbed in activated charcoal- a simple and safe radiation source for teaching practical radioactivity in schools and colleges

    Simple procedures for teaching practical radioactivity are presented in a way that attracts students' attention and does not make them apprehensive about their safety. The radiation source is derived from the natural environment. It is based on the radioactivity of radon, an ubiquitous inert gas, and the adsorptive property of activated charcoal. Radon gas from ambient air in the laboratory was adsorbed into about 70 gram of activated charcoal inside metallic canisters. Gamma radiation was subsequently emitted from the canisters, following the radioactive decay of radon and its progenies. The intensities of the emitted gamma-rays were measured at suitable intervals using a NaI gamma-ray detector. The counts obtained were analysed and used to demonstrate the radioactive decay law and determine the half-life of radon. In addition to learning the basic properties of radioactivity, the students also get practical experience about the existence of natural sources of radiation in the environment. (author)

  7. Application of Polarization Modulated Infrared Reflection Absorption Spectroscopy for electrocatalytic activity studies of laccase adsorbed on modified gold electrodes

    Orientation of the enzyme macromolecule on the electrode surface is crucially important for the efficiency of the electron transport between the active site and electrode surface. The orientation can be controlled by affecting the surface charge and the pH of the buffer solution. In this contribution we study laccase physically adsorbed on gold surface modified by mercapto-ethanol, lipid and variously charged diazonium salts. Polarization Modulated Infrared Reflection Absorption Spectroscopy (PMIRRAS) enables the molecular orientation study of the protein molecule by comparison of the amide I to amide II band intensity ratios assuming that the protein secondary structure does not change. We observe significant differences in the intensity ratios depending on the kind of support and the enzyme deposition. The comparison of infrared spectra and cyclic voltammetry responses of variously prepared laccase layers reveals that the parallel orientation of beta-sheet moieties results in high enzyme activity

  8. [Intraoperative chemotherapy against peritoneal dissemination of gastric cancer with intraperitoneal activated carbon particles adsorbing mitomycin C].

    Hagiwara, A; Takahashi, T; Sawai, K; Yamaguchi, T; Iwamoto, A; Yoneyama, C

    1989-02-01

    For prevention and therapy of peritoneal dissemination, a new dosage from (MMC-CH) comprising carbon particles adsorbing mitomycin C was given to 44 patients (the MMC-CH group) undergoing gastrectomy for gastric cancer, of which advancing stage was classified into the category of H0, and S2 or S3, and P0, P1, P2 or P3 according to the General Rules for the Gastric Cancer Study. MMC-CH, principally at 50 mg person in terms of mitomycin C was administered intraperitoneally before the surgical wound was closed. Historical control group was composed of 53 patients not given MMC-CH, who underwent gastrectomy for gastric cancer in the same advancing stage as those of the 44 patients. There was statistically no significant difference of age, sex, depth of infiltration, macroscopically and microscopically defined progression of lymph-nodal metastases, between the MMC-CH group and the historical control group. The survival rate of the overall patients, and each group of the patients with the lesion defined as P0, P1, P2, or P3 was compared with Kaplan-Meier's method between the MMC-CH group and the historical control group. In the MMC-CH group, the survival rates of the overall patients and the patients with P0, P1, or P2 lesion were statistically significantly higher than those in the historical control group. However, the rate of the P3 patients in the MMC-CH group was statistically significantly lower than in the historical control group. PMID:2493221

  9. Positronium chemistry in porous adsorbents

    Kinetic studies on the annihilation of orthopositronium in porous adsorbents have been performed using lifetime spectroscopy. The positron source applied was 22Na with 0.2 MBq activity. The adsorbents investigated were silica gels of different particle size and pore structure. The appearance of the long-lived component in the lifetime spectra can be explained by the diffusion of the orthopositronium into the pores affected by the particle size and the pore size of the adsorbent, the coverage on it and the chemical nature of the adsorbate. The long-term aim of the work is to determine and to explain these effects. (author)

  10. Hydrogen Adsorption in Carbon-Based Materials Studied by NMR

    Wu, Yue; Kleinhammes, Alfred; Anderson, Robert; Mao, Shenghua

    2007-03-01

    Hydrogen adsorption in carbon-based materials such as boron-doped graphite and boron-doped single-walled carbon nanotubes (SWNTs) were investigated by nuclear magnetic resonance (NMR). ^1H NMR is shown to be a sensitive and quantitative probe for detecting adsorbed gas molecules such as H2, methane, and ethane. NMR measurements were carried out in-situ under given H2 pressure up to a pressure of over 100 atm. From such ^1H NMR measurement, the amount of adsorbed H2 molecules was determined versus pressure. This gives an alternative method for measuring the adsorption isotherms where the H2 signature is identified based on spin properties rather than weight or volume as in gravimetric and volumetric measurements. The measurement shows that boron doping has a favorable effect on increasing the adsorption enthalpy of H2 in carbon-based systems. This work was done in collaboration with NREL and Department of Chemistry, University of Pennsylvania, within the DOE Center of Excellence on Carbon-based Hydrogen Storage Materials and is supported by DOE.

  11. 2, 4 dichlorophenol (2, 4-DCP) sorption from aqueous solution using granular activated carbon and polymeric adsorbents and studies on effect of temperature on activated carbon adsorption.

    Ghatbandhe, A S; Yenkie, M K N

    2008-04-01

    Adsorption equilibrium, kinetics and thermodynamics of 2,4-dichlorophenol (2,4-DCP), one of the most commonly used chlorophenol, onto bituminous coal based Filtrasorb-400 grade granular activated carbon, were studied in aqueous solution in a batch system with respect to temperature. Uptake capacity of activated carbon found to increase with temperature. Langmuir isotherm models were applied to experimental equilibrium data of 2, 4-DCP adsorption and competitive studies with respect to XAD resin were carried out. Equilibrium data fitted very well to the Langmuir equilibrium model. Adsorbent monolayer capacity 'Q0, Langmuir constant 'b' and adsorption rate constant 'k(a)' were evaluated at different temperatures for activated carbon adsorption. This data was then used to calculate the energy of activation of adsorption and also the thermodynamic parameters, namely the free energy of adsorption, deltaG0, enthalpy of adsorption, deltaH0 and the entropy of adsorption deltaS0. The obtained results showed that the monolayer capacity increases with the increase in temperatures. The obtained values of thermodynamic parameters showed that adsorption of 2,4 DCP is an endothermic process. Synthetic resin was not found efficient to adsorb 2,4 DCP compared to activated carbon. The order of adsorption efficiencies of three resins used in the study found as XAD7HP > XAD4 > XAD1180. PMID:19295102

  12. INCREASING ADSORPTION OF ACTIVATED CARBON FROM PALM OIL SHELL FOR ADSORB H2S FROM BIOGAS PRODUCTION BY IMPREGNATION

    Wasan Phooratsamee

    2014-01-01

    Full Text Available Biogas is the combustible gas produced through a biological process, known as anaerobic digestion which is the process operated at low-temperature and without air. Biogas consists of 55-80% CH4, 20-45% CO2 with trace amount of H2S and other impurities. Common H2S removal technologies from biogas fall into one of adsorption on a solid such as iron oxide based materials, activated carbon or impregnated activated carbon. Conventionally, activated carbon is produced from biomass residues and agricultural residues such as palm oil shell which promising approach for the production of cheap. It is so due to the palm oil shell carries a large amount of carbon content which it is the main composition of activated carbon. Therefore, it is usable as raw material for producing impregnated activated carbon and used as adsorbents. The aim of this study is a produce the activated carbon from palm oil shells by chemical activation using ZnCl2 and optimal conditions after impregnated them with NaOH, KI and K2CO3 for H2S absorption from biogas product. In this research, production of activated carbon involved three stages; (i carbonization of raw material in an inert atmosphere which was carbonized in a muffle furnace at 600°C for 1 h; (ii secondly activation of char product from the first stages at fixed bed reactor (stainless steel with 54.1 mm internal diameter and 320 mm length which was studied to observe the effect of char product: Chemical agent ratio (ZnCl2, 1:1 to 1:3, which there are activated at 700°C activation temperature for 2 h; and (iii finally alkali impregnated activated carbon which were immersed 1:3 ratio in 500 mL of 1 N NaOH, KI and K2CO3 solutions and stirred for 30 min. The result showed that the surface area and the pore volume increased progressively with increasing the char product: Chemical agent ratio. The maximum

  13. Thermal activation and characterization of clay Brasgel aiming your application as adsorbent in removal of nickel

    The clays exhibit interesting properties in adsorption of heavy metals in wastewater. This property can be modified by thermal activation. In this work, the characterization of clay Brasgel before and after thermal activation (200 deg C 300 deg C 400 deg C and 500 deg C) is performed by cation exchange capacity (CEC), X-ray Spectroscopy for Energy Dispersion (EDX), X-ray diffraction (XRD) and Differential Thermal Analysis and Gravimetric (DTA / TG). The main differences between natural and activated clays are the structural changes observed by XRD and DTA / TG. (author)

  14. Activity and Spatial Distribution of Candida antarctica Lipase B Immobilized on Macroporous Organic Polymeric Adsorbents

    Nielsen, Anne Veller Friis; Andric, Pavle; Munk Nielsen, Per;

    2014-01-01

    and PS catalysts, respectively, whereas no rim was observed in the absence of enzyme. Statistical analyses showed that carrier type was the major e ff ect in determining the activities of the catalysts, with enzyme load being the second most significant effect and particle size also exerting a......A systematic study of the influence of carrier particle size (500 − 850 μ m) and enzyme load (26 200 − 66 100 lipase activity units (LU)/g dry carrier) on the content and activity of Candida antarctica lipase B (CALB) immobilized by adsorption onto macroporous poly(methyl methacrylate) (PMM) and...... polystyrene (PS) carriers was conducted. Furthermore, localization of CALB on the carrier was investigated by light and fluorescence microscopy of freeze microtome sliced catalyst particles. Fluorescence microscopy showed localization of enzyme in an outer rim of 50 − 85 and 10 − 20 μ m thickness for the PMM...

  15. Facile preparation of magnetic separable powdered-activated-carbon/Ni adsorbent and its application in removal of perfluorooctane sulfonate (PFOS) from aqueous solution.

    Liang, Xuanqi; Gondal, Mohammed A; Chang, Xiaofeng; Yamani, Zain H; Li, Nianwu; Lu, Hongling; Ji, Guangbin

    2011-01-01

    The main aim of this study was to synthesize magnetic separable Nickel/powdered activated carbon (Ni/PAC) and its application as an adsorbent for removal of PFOS from aqueous solution. In this work, the synthesized adsorbent using simple method was characterized by using X-ray diffractionometer (XRD), surface area and pore size analyzer, vibrating sample magnetometer (VSM), and high resolution transmission electron microscope (HRTEM). The surface area, pore volume and pore size of synthesized PAC was 1521.8 m(2)g(-1), 0.96 cm(3)g(-1), 2.54 nm, respectively. Different kinetic models: the pseudo-first-order model, the pseudo-second-order model, and three adsorption isotherms--Langmuir, Freundlich and Temkin--were applied to study the sorption kinetics and isothermal behavior of PFOS onto the surface of an as-prepared adsorbent. The rate constant using the pseudo-second-order model for removal of 150 ppm PFOS was estimated as 8.82×10(-5) and 1.64×10(-4) for PAC and 40% Ni/PAC, respectively. Our results demonstrated that the composite adsorbents exhibited a clear magnetic hysteretic behavior, indicating the potential practical application in magnetic separation of adsorbents from aqueous solution phase as well. PMID:21961696

  16. New type adsorbent material of impregnated activated carbon fibers for iodine filter

    Impregnated granular activated carbon bed filters have been used worldwide to treat nuclear power plant exhaust gases of containing iodine and extensive experimental studies have been conducted. It has been discovered that the impregnated granular activated carbon has some inherent defect such as the ignition temperature is lower, the adsorption efficiency and capacity were lower and affected strongly by relative humidity and the adsorption velocity is lower. A new type impregnated activated carbon fibers (IACF) material was developed. The IACF is a felt material which has a wealth of micropores, low apparent density, high chemical stability, significantly higher ignition temperature, low affinity for water, high adsorption velocity, and the shape of IACF can be tailored to achieve the best adsorption results. Therefore, the IACF is possessed of a high adsorption capacity and efficiency in high relative humidity (> 95% R.H.). According to the ASTM D 3803 method A test, the result showed that the adsorption efficiency of >99% in bed depth of 2.5 cm. In this work, the various surface structural parameters, surface chemical characteristics and adsorption dynamics were studied by the x-ray diffraction, infrared absorption, and x-ray photoelectron spectrometry method. The results show that the various characteristics of the IACF are better than existing nuclear grade granular activated carbon

  17. VERUCLAY – a new type of photo-adsorbent active in the visible light range: modification of montmorillonite surface with organic surfactant

    Montmorillonite K10 was treated with VeruSOL-3, a biodegradable and food-grade surfactant mixture of coconut oil, castor oil and citrus extracts, to manufacture a benign catalytic adsorbent that is active in the visible light. Veruclay was characterized by SEM, XRD, TGA, UVDRS, a...

  18. The recognition of adsorbed and denatured proteins of different topographies by β2 integrins and effects on leukocyte adhesion and activation

    Brevig, T.; Holst, B.; Ademovic, Z.;

    2005-01-01

    Leukocyte beta(2) integrins Mac-1 and p150,95 are promiscuous cell-surface receptors that recognise and mediate cell adhesion to a variety of adsorbed and denatured proteins. We used albumin as a model protein to study whether leukocyte adhesion and activation depended on the nm-scale topography ...

  19. Solid-phase microextraction of phthalate esters in water sample using different activated carbon-polymer monoliths as adsorbents.

    Lirio, Stephen; Fu, Chung-Wei; Lin, Jhih-Yun; Hsu, Meng-Ju; Huang, Hsi-Ya

    2016-07-13

    In this study, the application of different activated carbon-polymer (AC-polymer) monoliths as adsorbents for the solid-phase microextraction (SPME) of phthalate esters (PAEs) in water sample were investigated. The activated carbon (AC) was embedded in organic polymers, poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-EDMA)) or poly(styrene-co-divinylbenzene) (poly(STY-DVB)), via a 5-min microwave-assisted or a 15-min water bath heating polymerization. Preliminary investigation on the performance of the native poly(BMA-EDMA) and poly(STY-DVB) demonstrated remarkable adsorption efficiencies for PAEs. However, due to the strong hydrophobic, π-π, and hydrogen bonding interactions between the analytes and polymers, low extraction recoveries were achieved. In contrast, the presence of AC in native polymers not only enhanced the adsorption efficiencies but also assisted the PAE desorption, especially for AC-poly(STY-DVB) with extraction recovery ranged of 76.2-99.3%. Under the optimized conditions, the extraction recoveries for intra-, inter-day and column-to-column were in the range of 76.5-100.8% (DVB) monolithic column showed good mechanical stability, which can be reused for more than 30 extraction times without any significant loss in the extraction recoveries of PAEs. The AC-poly(STY-DVB) monolithic column was successfully applied in SPME of PAEs in water sample with extraction recovery ranged of 78.8%-104.6% (<5.5% RSDs). PMID:27237837

  20. Cheap adsorbent. Part 1: active cokes from lignites and improvement of their adsorptive properties by mild oxidation

    Finqueneisel, G.; Zimny, T.; Albiniak, A.; Siemieniewska, T.; Vogt, D.; Weber, J.V. [Laboratoire de Chimie Industrielle, Saint-Avold (France)

    1998-05-01

    Cheap adsorbents were produced starting from two different lignites. About 500 kg of each coal was pyrolyzed in a rotary kiln at semi-pilot scale. Characterization of the obtained chars is made in terms of porosity development, surface functional groups and adsorptive properties determined for both 4-nitrophenol and lead. A post-oxidative treatment at low temperature is proposed in order to improve the adsorptive capacities of the initial chars by the introduction of oxygen containing functional groups, which are widely involved in chemisorption. The conditions of the post-treatment were chosen to be easily exported in an industrial process, for example during the cooling step. The importance of both lignite characteristics (ash content, water content) and pyrolysis conditions is demonstrated. The positive effect of a simple post-oxidative treatment is shown by a strong increase in the adsorptive capacities, and correlated to the evolution of the porosites and surface oxygen functionalities. Considering unit area, the properties of the active cokes are similar to those of commercial active carbon, but their specific areas are less developed (about 400 m{sup 2} g{sup -1}). 17 refs., 7 figs., 7 tabs.

  1. Adsorbed natural gas storage with activated carbons made from Illinois coals and scrap tires

    Sun, Jielun; Brady, T.A.; Rood, M.J.; Lehmann, C.M.; Rostam-Abadi, M.; Lizzio, A.A.

    1997-01-01

    Activated carbons for natural gas storage were produced from Illinois bituminous coals (IBC-102 and IBC-106) and scrap tires by physical activation with steam or CO2 and by chemical activation with KOH, H3PO4, or ZnCl2. The products were characterized for N2-BET area, micropore volume, bulk density, pore size distribution, and volumetric methane storage capacity (Vm/Vs). Vm/Vs values for Illinois coal-derived carbons ranged from 54 to 83 cm3/cm3, which are 35-55% of a target value of 150 cm3/cm3. Both granular and pelletized carbons made with preoxidized Illinois coal gave higher micropore volumes and larger Vm/Vs values than those made without preoxidation. This confirmed that preoxidation is a desirable step in the production of carbons from caking materials. Pelletization of preoxidized IBC-106 coal, followed by steam activation, resulted in the highest Vm/Vs value. With roughly the same micropore volume, pelletization alone increased Vm/Vs of coal carbon by 10%. Tire-derived carbons had Vm/Vs values ranging from 44 to 53 cm3/cm3, lower than those of coal carbons due to their lower bulk densities. Pelletization of the tire carbons increased bulk density up to 160%. However, this increase was offset by a decrease in micropore volume of the pelletized materials, presumably due to the pellet binder. As a result, Vm/Vs values were about the same for granular and pelletized tire carbons. Compared with coal carbons, tire carbons had a higher percentage of mesopores and macropores.

  2. Prediction and Simulation the Breakthrough of Residual Chlorine Removal by Granular Activated Carbon Adsorbent Using Artificial Neural Networks

    Rusul Naseer

    2012-07-01

    Full Text Available This study has included two parts. The first part has dealt with carbon production whereas the date Palm was used to produce Granular Activated Carbon (GAC with specific physical characteristics. The new produced of GAC is used to adsorbate the Residual chlorine from water by deep bed filter column. In the second part, the experimental results of the breakthrough of residual chlorine curves is predicted and simulated using artificial neural network with back propagation algorithm whereas the optimum number of neuron was investigated based on RMSE. The removal of residual chlorine has been used as target function in ANN while the other properties of adsorption process such as operation conditions, chlorine concentration in raw water and GAC characteristics has been used as input parameters. The results showed that ANN with back propagation algorithm is a good tool that can be used to predict the best operating parameter for designing GAC layer in multimedia filter whereas 35 neuron gave the best fitting with experimental data. In addition to that, the simulation result was showed that the predictions of breakthrough curve model has been coincided well with the measured values which explained that the depth 25 cm with grain size 1.5 mm of GAC filter bed will be give the optimum removal of residual chlorine from chlorinated water.

  3. Study on the oxygen adsorption property of nitrogen-containing metal-free carbon-based cathode catalysts for oxygen reduction reaction

    We study the characteristics of oxygen adsorption on metal-free carbon-based cathode catalysts derived from nitrogen-containing polyamide (PA) and nitrogen-free phenolic resin (PhRs). Electrochemical analysis and Raman spectroscopy showed higher 2-electron oxygen reduction reaction (ORR) activity and more defect sites in PA than PhRs. The increase in the amount of adsorbed oxygen in PA was also identified by oxygen adsorption isotherms. In situ X-ray photoelectron spectroscopy revealed that graphite-like nitrogen contributes to oxygen adsorption and C=O components are dominant in PA. These experimental results indicate that the adsorbed C=O components near the graphite-like nitrogen can be assigned as active sites for 2-electron ORR.

  4. Optimization of Preparation Condition for Meso pores Activated Carbon based on Hevea Brasiliensis Seed Coat for the Removal of Remazol Brilliant Blue R Dye

    The conditions for the preparation of rubber (hevea brasiliensis) seed coat based activated carbon (RSCAC) treated with NaOH were optimized through response surface methodology (RSM). The effects of three preparation variables: the activation temperature, activation time and NaOH impregnation ratio (IR) on Remazol Brilliant Blue R (RBBR) removal from aqueous solutions and RSCAC yield were investigated. Based on the RSM, two quadratic models were respectively developed to correlate the preparation variables to the RBBR percentage removal and carbon yield. The significant factors on each experimental design response were identified from the analysis of variance (ANOVA). The optimum conditions for RSCAC preparation were obtained by using activation temperature of 700 degree Celsius, activation time of 1.0 h and IR of 1.0, which resulted in 70.82 % of RBBR removal and 24.93 % of RSCAC yield. (author)

  5. Comparison of Spirulina platensis microalgae and commercial activated carbon as adsorbents for the removal of Reactive Red 120 dye from aqueous effluents

    Highlights: ► Spirulina platensis (SP) and activated carbon (AC) were used to remove RR-120 dye. ► The maximum adsorption capacities were found at pH 2 and 298 K. ► The values were 482.2 and 267.2 mg g−1 for SP and AC, respectively. ► Adsorption was exothermic, spontaneous and favorable. ► SP and AC were effective to treat a simulated dye-house effluent. - Abstract: Spirulina platensis microalgae (SP) and commercial activated carbon (AC) were compared as adsorbents to remove Reactive Red 120 (RR-120) textile dye from aqueous effluents. The batch adsorption system was evaluated in relation to the initial pH, contact time, initial dye concentration and temperature. An alternative kinetic model (general order kinetic model) was compared with the traditional pseudo-first order and pseudo-second order kinetic models. The equilibrium data were fitted to the Langmuir, Freundlich and Liu isotherm models, and the thermodynamic parameters were also estimated. Finally, the adsorbents were employed to treat a simulated dye-house effluent. The general order kinetic model was more appropriate to explain RR-120 adsorption by SP and AC. The equilibrium data were best fitted to the Liu isotherm model. The maximum adsorption capacities of RR-120 dye were found at pH 2 and 298 K, and the values were 482.2 and 267.2 mg g−1 for the SP and AC adsorbents, respectively. The thermodynamic study showed that the adsorption was exothermic, spontaneous and favourable. The SP and AC adsorbents presented good performance for the treatment of simulated industrial textile effluents, removing 94.4–99.0% and 93.6–97.7%, respectively, of the dye mixtures containing high saline concentrations.

  6. Comparison of Spirulina platensis microalgae and commercial activated carbon as adsorbents for the removal of Reactive Red 120 dye from aqueous effluents

    Cardoso, Natali F. [Institute of Chemistry, Federal University of Rio Grande do Sul, UFRGS, AV. Bento Goncalves 9500, 91501-970, Porto Alegre, RS (Brazil); Lima, Eder C., E-mail: profederlima@gmail.com [Institute of Chemistry, Federal University of Rio Grande do Sul, UFRGS, AV. Bento Goncalves 9500, 91501-970, Porto Alegre, RS (Brazil); Royer, Betina; Bach, Marta V. [Institute of Chemistry, Federal University of Rio Grande do Sul, UFRGS, AV. Bento Goncalves 9500, 91501-970, Porto Alegre, RS (Brazil); Dotto, Guilherme L.; Pinto, Luiz A.A. [Unit Operation Laboratory, School of Chemistry and Food, Federal University of Rio Grande, FURG, R. Engenheiro Alfredo Huch 475, 96201-900, Rio Grande, RS (Brazil); Calvete, Tatiana [Universitary Center La Salle (UNILASALLE), Av. Victor Barreto 2288, 92010-000, Canoas, RS (Brazil)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Spirulina platensis (SP) and activated carbon (AC) were used to remove RR-120 dye. Black-Right-Pointing-Pointer The maximum adsorption capacities were found at pH 2 and 298 K. Black-Right-Pointing-Pointer The values were 482.2 and 267.2 mg g{sup -1} for SP and AC, respectively. Black-Right-Pointing-Pointer Adsorption was exothermic, spontaneous and favorable. Black-Right-Pointing-Pointer SP and AC were effective to treat a simulated dye-house effluent. - Abstract: Spirulina platensis microalgae (SP) and commercial activated carbon (AC) were compared as adsorbents to remove Reactive Red 120 (RR-120) textile dye from aqueous effluents. The batch adsorption system was evaluated in relation to the initial pH, contact time, initial dye concentration and temperature. An alternative kinetic model (general order kinetic model) was compared with the traditional pseudo-first order and pseudo-second order kinetic models. The equilibrium data were fitted to the Langmuir, Freundlich and Liu isotherm models, and the thermodynamic parameters were also estimated. Finally, the adsorbents were employed to treat a simulated dye-house effluent. The general order kinetic model was more appropriate to explain RR-120 adsorption by SP and AC. The equilibrium data were best fitted to the Liu isotherm model. The maximum adsorption capacities of RR-120 dye were found at pH 2 and 298 K, and the values were 482.2 and 267.2 mg g{sup -1} for the SP and AC adsorbents, respectively. The thermodynamic study showed that the adsorption was exothermic, spontaneous and favourable. The SP and AC adsorbents presented good performance for the treatment of simulated industrial textile effluents, removing 94.4-99.0% and 93.6-97.7%, respectively, of the dye mixtures containing high saline concentrations.

  7. Preparation of carbonaceous adsorbents from sewage sludge by chemical activation process - application to air and water treatments

    Rio, S.; Le Coq, L.; Faur-Brasquet, C.; Le Cloirec, P. [Ecole des Mines de Nantes (UMR CNRS 6144 GEPEA), 44 - Nantes (France)

    2004-07-01

    . Firstly, activation mass yield decreases from 45 % to 36 % with increasing temperature and time, when the increase of impregnation ratio has a positive effect on this experimental design response. Surface pH and pH{sub pzc} measurements show that sorbents are acid. And, amount of acidic surface groups are more important that basic groups. The increase of temperature and time leads to a decrease of surface groups, whereas the increase of impregnation ratio allows acidic surface groups to be increased. Then, experimental design factors influence porosity development within the samples. The increase of impregnation ratio leads to specific surface area and pore volumes to be developed. And, at temperature above 700 C, A pore widening or destruction phenomenon would occur, leading to a decrease of specific surface area and micro-pore volume. Carbonaceous sorbents developed from sludge allow copper ion, phenol and dyes to be removed from aqueous solution as well as VOC from gas phase. According to experimental conditions, copper adsorption capacity varies from 77 to 83 mg g{sup -1}, phenol adsorption capacity varies between 41-53 mg g{sup -1} and VOC adsorption capacities (acetone and toluene) range from 12 to 54 mg g{sup -1}. The organic pollutant adsorption may be related with porous properties, whereas copper adsorption is dependent on the surface chemistry of the adsorbents. Finally, surface response methodology enable to define the following optimal conditions, 700 C during 145-160 min with impregnation ratio of 1.5 g g{sup -1}, that are more appropriate for use of sludge-based sorbent in water and gas treatments. (authors)

  8. High surface adsorption properties of carbon-based nanomaterials are responsible for mortality, swimming inhibition, and biochemical responses in Artemia salina larvae

    Mesarič, Tina, E-mail: tina.mesaric84@gmail.com [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Gambardella, Chiara, E-mail: chiara.gambardella@ge.ismar.cnr.it [Institute of Marine Sciences, National Research Council, Genova (Italy); Milivojević, Tamara, E-mail: milivojevictamara@gmail.com [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Faimali, Marco, E-mail: marco.faimali@ismar.cnr.it [Institute of Marine Sciences, National Research Council, Genova (Italy); Drobne, Damjana, E-mail: damjana.drobne@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Centre of Excellence in Nanoscience and Nanotechnology (CO Nanocentre), Ljubljana (Slovenia); Centre of Excellence in Advanced Materials and Technologies for the Future (CO NAMASTE), Ljubljana (Slovenia); Falugi, Carla, E-mail: carlafalugi@hotmail.it [Department of Earth, Environment and Life Sciences, University of Genova, Genova (Italy); Makovec, Darko, E-mail: darko.makovec@ijs.si [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Jemec, Anita, E-mail: anita.jemec@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Sepčić, Kristina, E-mail: kristina.sepcic@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia)

    2015-06-15

    Highlights: • Carbon-based nanomaterials adsorb onto the body surface of A. salina larvae. • Surface adsorption results in concentration–dependent inhibition of larval swimming. • Carbon-based nanomaterials induce no significant mortality of A. salina larvae. - Abstract: We investigated the effects of three different carbon-based nanomaterials on brine shrimp (Artemia salina) larvae. The larvae were exposed to different concentrations of carbon black, graphene oxide, and multiwall carbon nanotubes for 48 h, and observed using phase contrast and scanning electron microscopy. Acute (mortality) and behavioural (swimming speed alteration) responses and cholinesterase, glutathione-S-transferase and catalase enzyme activities were evaluated. These nanomaterials were ingested and concentrated in the gut, and attached onto the body surface of the A. salina larvae. This attachment was responsible for concentration–dependent inhibition of larval swimming, and partly for alterations in the enzyme activities, that differed according to the type of tested nanomaterials. No lethal effects were observed up to 0.5 mg/mL carbon black and 0.1 mg/mL multiwall carbon nanotubes, while graphene oxide showed a threshold whereby it had no effects at 0.6 mg/mL, and more than 90% mortality at 0.7 mg/mL. Risk quotients calculated on the basis of predicted environmental concentrations indicate that carbon black and multiwall carbon nanotubes currently do not pose a serious risk to the marine environment, however if uncontrolled release of nanomaterials continues, this scenario can rapidly change.

  9. High surface adsorption properties of carbon-based nanomaterials are responsible for mortality, swimming inhibition, and biochemical responses in Artemia salina larvae

    Highlights: • Carbon-based nanomaterials adsorb onto the body surface of A. salina larvae. • Surface adsorption results in concentration–dependent inhibition of larval swimming. • Carbon-based nanomaterials induce no significant mortality of A. salina larvae. - Abstract: We investigated the effects of three different carbon-based nanomaterials on brine shrimp (Artemia salina) larvae. The larvae were exposed to different concentrations of carbon black, graphene oxide, and multiwall carbon nanotubes for 48 h, and observed using phase contrast and scanning electron microscopy. Acute (mortality) and behavioural (swimming speed alteration) responses and cholinesterase, glutathione-S-transferase and catalase enzyme activities were evaluated. These nanomaterials were ingested and concentrated in the gut, and attached onto the body surface of the A. salina larvae. This attachment was responsible for concentration–dependent inhibition of larval swimming, and partly for alterations in the enzyme activities, that differed according to the type of tested nanomaterials. No lethal effects were observed up to 0.5 mg/mL carbon black and 0.1 mg/mL multiwall carbon nanotubes, while graphene oxide showed a threshold whereby it had no effects at 0.6 mg/mL, and more than 90% mortality at 0.7 mg/mL. Risk quotients calculated on the basis of predicted environmental concentrations indicate that carbon black and multiwall carbon nanotubes currently do not pose a serious risk to the marine environment, however if uncontrolled release of nanomaterials continues, this scenario can rapidly change

  10. Desulfurization of liquid fuels by adsorption on carbon-based sorbents and ultrasound-assisted sorbent regeneration.

    Wang, Yuhe; Yang, Ralph T

    2007-03-27

    Several carbon-based adsorbents, CuCl/AC, PdCl2/AC, and Pd/AC (where AC denotes activated carbon), were studied for desulfurization of a model jet fuel by selective adsorption of thiophenic molecules. Comparisons with gamma-Al2O3 support and desulfurization of a commercial jet fuel were also studied. The results showed that the selective sulfur adsorption capacity of PdCl2 was higher than that of CuCl and Pd(0), in agreement with molecular orbital results. It was also found that the activated carbon is the best support for pi-complexation sorbents to remove sulfur-containing compounds, i.e., benzothiophene and methylbenzothiophene. Among all the adsorbents studied, PdCl2/AC had the highest capacity for desulfurization. A significant synergistic effect was observed between the carbon substrate and the supported pi-complexation sorbent, and this effect was explained by a geometric effect. The saturated sorbent was regenerated by desorption assisted by ultrasound with a solvent of 30 wt % benzene and 70 wt % n-octane. The results showed that the amount of sulfur desorbed was higher with ultrasound, 65 wt % desorption vs 45 wt % without ultrasound in a static system at 50 degrees C. PMID:17315903

  11. 活性炭吸附法处理苯乙酸工艺废水中甲苯的模拟研究%USING ACTIVE CARBON ADSORBENT TO TREAT METHYLBENZENE IN SIMULATED WASTEWATER OF PHENYLACETIC ACID PRODUCTION

    罗明亮; 杨庆良

    2000-01-01

    Active carbon has been widely used to treat wastewater.In this paper active carb on adsorbent is used to treat methylbenzene resulting from the production of phenylacetic acid.Our experiment indicates that acidity has no effect on adsorb ability.At temperature 22℃ and flow rate 1Bv/h,adsorption efficiency of methyl benzen is 94.2% and erasing rate of CODCr reaches 94.9%.Alkaline-alcohol solution is employed as an eluent to regenerate active carbon.After regeneratio n,adsorption efficiency of methylbenzene is 86.4% and the erasing rate of COD Cr is 87.3%.

  12. Ecological applications of the irradiated adsorbents

    Full text: In our previous works it was shown that after irradiation some adsorbents gain new interesting properties such as increasing (or decreasing) of their adsorption capacity, selectivity in relation to some gases, change of chemical bounds of gas molecules with adsorbent surface as well as other properties. We investigated a lot of adsorbents with semiconducting and dielectric properties. A high temperature superconductor was investigated also. Adsorbents were irradiated by ultraviolet (UV) and gamma - radiation, reactor (n.γ) - radiation, α-particles (E=40-50 MeV), protons ( E=30 MeV), and also He-3 ions (E-29-60 MeV). The following techniques were used: volumetric (manometrical), mass-spectrometer and IR spectroscopic methods, and also method of electronic - paramagnetic resonance (spin paramagnetic resonance) The obtained results allow to speak about creation of new adsorbents for gas purification (clearing) from harmful impurities, gas selection into components, an increasing of adsorbing surface. Thus one more advantage of the irradiated adsorbents is that they have 'memory effect', i.e. they can be used enough long time after irradiation. In laboratory conditions we built the small-sized adsorptive pump on the basis of the irradiated zeolites which are capable to work in autonomous conditions. It was found, that some of adsorbents after irradiation gain (or lose) selectivity in relation to definite gases. So, silica gel, which one in initial state does not adsorb hydrogen, after gamma irradiation it becomes active in relation to hydrogen. Some of rare earths oxides also show selectivity in relation to hydrogen and oxygen depending on a type of irradiation. Thus, it is possible to create different absorbents, depending on a solved problem, using a way or selection of adsorbents, either of radiation type and energy, as a result obtained adsorbents can be used for various ecological purposes

  13. Magnetic composite of Fe3O4 and activated carbon as a adsorbent for separation of trace Sr(II) from radioactive wastewater

    Magnetic adsorbent of Fe3O4 and activated carbon (Fe3O4/AC) was prepared by chemical coprecipitation technique, and was characterized by SEM, TEM, BET, XRD, and VSM techniques in details. The adsorption results of Sr(II) on Fe3O4/AC revealed that Sr(II) adsorption on Fe3O4/AC surface was an spontaneous and endothermic process, and can be well described by the pseudo-second-order model. The adsorption of Sr(II) on Fe3O4/AC increased with increasing pH, and decreased with increasing ionic strength. Fe3O4/AC can be easily separated from aqueous solution with an external magnetic field after application. (author)

  14. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    Xuezheng Liang

    2010-08-01

    Full Text Available The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and β-keto esters make this novel carbon based acid one of the best choices for the reaction.

  15. Adsorptive removal of hydrophobic organic compounds by carbonaceous adsorbents: A comparative study of waste-polymer-based,coal-based activated carbon, and carbon nanotubes

    Fei Lian; Chun Chang; Yang Du; Lingyan Zhu; Baoshan Xing; Chang Liu

    2012-01-01

    Adsorption of the hydrophobic organic compounds (HOCs) trichloroethylene (TCE),1,3-dichlorobenzene (DCB),1,3-dinitrobenzene (DNB) and γ-hexachlorocyclohexane (HCH) on five different carbonaceous materials was compared.The adsorbents included three polymer-based activated carbons,one coal-based activated carbon (F400) and multiwalled carbon nanotubes (MWNT).The polymerbased activated carbons were prepared using KOH activation from waste polymers:polyvinyl chloride (PVC),polyethyleneterephthalate (PET) and tire rubber (TR).Compared with F400 and MWNT,activated carbons derived from PVC and PET exhibited fast adsorption kinetics and high adsorption capacity toward the HOCs,attributed to their extremely large hydrophobic surface area (2700 m2/g) and highly mesoporous structures.Adsorption of small-sized TCE was stronger on the tire-rubber-based carbon and F400 resulting from the pore-filling effect.In contrast,due to the molecular sieving effect,their adsorption on HCH was lower.MWNT exhibited the lowest adsorption capacity toward HOCs because of its low surface area and characteristic of aggregating in aqueous solution.

  16. Carbon-based tribofilms from lubricating oils.

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K R S

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid 'tribofilms', which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant's anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm. PMID:27488799

  17. Carbon-based tribofilms from lubricating oils

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L.; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K. R. S.

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid ‘tribofilms’, which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant’s anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon–carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

  18. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    Xuezheng Liang; Shao-Qin Lv; Lin-Mei Rong; Sheng-Xian Zhao; Chunqing Li; Baowei Hu; Chenze Qi

    2010-01-01

    The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols ...

  19. Advanced fire-resistant forms of activated carbon and methods of adsorbing and separating gases using same

    Xiong, Yongliang; Wang, Yifeng

    2016-04-19

    A method of removing a target gas from a gas stream is disclosed. The method uses advanced, fire-resistant activated carbon compositions having vastly improved fire resistance. Methods for synthesizing the compositions are also provided. The advanced compositions have high gas adsorption capacities and rapid adsorption kinetics (comparable to commercially-available activated carbon), without having any intrinsic fire hazard.

  20. Recent progress on carbon-based superconductors

    Kubozono, Yoshihiro; Eguchi, Ritsuko; Goto, Hidenori; Hamao, Shino; Kambe, Takashi; Terao, Takahiro; Nishiyama, Saki; Zheng, Lu; Miao, Xiao; Okamoto, Hideki

    2016-08-01

    This article reviews new superconducting phases of carbon-based materials. During the past decade, new carbon-based superconductors have been extensively developed through the use of intercalation chemistry, electrostatic carrier doping, and surface-proving techniques. The superconducting transition temperature T c of these materials has been rapidly elevated, and the variety of superconductors has been increased. This review fully introduces graphite, graphene, and hydrocarbon superconductors and future perspectives of high-T c superconductors based on these materials, including present problems. Carbon-based superconductors show various types of interesting behavior, such as a positive pressure dependence of T c. At present, experimental information on superconductors is still insufficient, and theoretical treatment is also incomplete. In particular, experimental results are still lacking for graphene and hydrocarbon superconductors. Therefore, it is very important to review experimental results in detail and introduce theoretical approaches, for the sake of advances in condensed matter physics. Furthermore, the recent experimental results on hydrocarbon superconductors obtained by our group are also included in this article. Consequently, this review article may provide a hint to designing new carbon-based superconductors exhibiting higher T c and interesting physical features.

  1. Recent progress on carbon-based superconductors.

    Kubozono, Yoshihiro; Eguchi, Ritsuko; Goto, Hidenori; Hamao, Shino; Kambe, Takashi; Terao, Takahiro; Nishiyama, Saki; Zheng, Lu; Miao, Xiao; Okamoto, Hideki

    2016-08-24

    This article reviews new superconducting phases of carbon-based materials. During the past decade, new carbon-based superconductors have been extensively developed through the use of intercalation chemistry, electrostatic carrier doping, and surface-proving techniques. The superconducting transition temperature T c of these materials has been rapidly elevated, and the variety of superconductors has been increased. This review fully introduces graphite, graphene, and hydrocarbon superconductors and future perspectives of high-T c superconductors based on these materials, including present problems. Carbon-based superconductors show various types of interesting behavior, such as a positive pressure dependence of T c. At present, experimental information on superconductors is still insufficient, and theoretical treatment is also incomplete. In particular, experimental results are still lacking for graphene and hydrocarbon superconductors. Therefore, it is very important to review experimental results in detail and introduce theoretical approaches, for the sake of advances in condensed matter physics. Furthermore, the recent experimental results on hydrocarbon superconductors obtained by our group are also included in this article. Consequently, this review article may provide a hint to designing new carbon-based superconductors exhibiting higher T c and interesting physical features. PMID:27351938

  2. Molecular Adsorber Coating

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  3. Activity of ruthenium, rhodium, iridium-ruthenium and iridium-rhodium adsorbed catalysts in dehydrogenation of formic acid

    The activity of Ru-, Rh- (Ir+nRu)- and (Ir+nRn) catalysts on sugar carbon and silicon dioxide in decomposition of HCOOH was studied. The catalyst activity increases in the series Ir1 and (Rh)1 in the reaction of dehydration of HCOOH. It is shown that in the course of preparation of (Ir+nRh)- and (Ir+nRu)-catalysts the Ir atoms interact with Ru(Rh), and variable-composition structures are formed

  4. Graphene nanosheets as novel adsorbents in adsorption, preconcentration and removal of gases, organic compounds and metal ions

    Due to their high adsorption capacities, carbon-based nanomaterials such as carbon nanotubes, activated carbons, fullerene and graphene are widely used as the currently most promising functional materials. Since its discovery in 2004, graphene has exhibited great potential in many technological fields, such as energy storage materials, supercapacitors, resonators, quantum dots, solar cells, electronics, and sensors. The large theoretical specific surface area of graphene nanosheets (2630 m2·g−1) makes them excellent candidates for adsorption technologies. Further, graphene nanosheets could be used as substrates for decorating the surfaces of nanoparticles, and the corresponding nanocomposites could be applied as novel adsorbents for the removal of low concentrated contaminants from aqueous solutions. Therefore, graphene nanosheets will challenge the current existing adsorbents, including other types of carbon-based nanomaterials. - Highlights: • The recent progress of application of graphene in adsorption was presented. • The design and practical application of graphene based composites was discussed. • The future trends and prospects of graphene were analyzed and proposed

  5. Radon Adsorbed in Activated Charcoal--A Simple and Safe Radiation Source for Teaching Practical Radioactivity in Schools and Colleges

    Al-Azmi, Darwish; Mustapha, Amidu O.; Karunakara, N.

    2012-01-01

    Simple procedures for teaching practical radioactivity are presented in a way that attracts students' attention and does not make them apprehensive about their safety. The radiation source is derived from the natural environment. It is based on the radioactivity of radon, a ubiquitous inert gas, and the adsorptive property of activated charcoal.…

  6. Properties and selection criteria for adsorbents

    The paper gives a survey of the most important industrial adsorbents and of their suitability for different purposes. With special consideration of activated carbon, the properties and characteristic data are discussed which are used for assessing adsorbents. These, among other things, are as follows: specific surface area, pore size distribution, adsorption isotherms, hydrophobic properties, catalytic properties, chemical resistance, heat resistance, particle size and hardness. (orig.)

  7. Antibody-directed targeting of lysostaphin adsorbed onto polylactide nanoparticles increases its antimicrobial activity against S. aureus in vitro

    The objective of this paper was to study the effect of antibody-directed targeting of S. aureus by comparing the activities of lysostaphin conjugated to biodegradable polylactide nanoparticles (NPs) in the presence and in the absence of co-immobilized anti-S. aureus antibody. Lysostaphin–antibody–NP conjugates were synthesized through physical adsorption at different enzyme:antibody:NP ratios. The synthesized enzyme–NP conjugates were characterized by means of dynamic light scattering and zeta potential analysis, and the total protein binding yield on the NPs was characterized using Alexa Fluor 350 and 594 dyes for the S. aureus antibody and lysostaphin respectively. We observed enhanced antimicrobial activity for both enzyme-coated and enzyme–antibody-coated NPs for lysostaphin coatings corresponding to ∼ 40% of the initial monolayer and higher compared to the free enzyme case (p < 0.05). At the highest antibody coating concentration, bacterial lysis rates for antibody-coated samples were significantly higher than for lysostaphin-coated samples lacking the antibody (p < 0.05). Such enzyme–NP conjugates thus have the potential for becoming novel therapeutic agents for treating antibiotic-resistant S. aureus infections.

  8. Enhanced visible-light-induced photocatalytic activity of α-Fe2O3 adsorbing redox enzymes

    Kai Kamada

    2015-03-01

    Full Text Available We report fabrication of hybrid photocatalyst composed of an n-type semiconductor (α-Fe2O3 and a redox enzyme (horseradish peroxidase; HRP, and its performance for oxidation of luminol in an aqueous solution. The hybrid photocatalyst is simply formed via physical adsorption of HRP to an α-Fe2O3 sintered body. Under visible light irradiation, the bare α-Fe2O3 with a narrow bandgap photocatalytically oxidizes luminol along with blue emission that can be used as an indicator of the photocatalytic performance. The blue emission is largely strengthened after the adsorption of HRP, demonstrating that the presence of enzyme improves apparent photocatalytic activity of α-Fe2O3. The favorable effect is derived from synergistic oxidation of luminol by the biocatalysts (HRP as well as by the photocatalyst (α-Fe2O3. In this paper, influence of excitation wavelength, adsorption amount of HRP, and reaction temperature on the overall photocatalytic activity are elucidated, and then a reaction mechanism of the proposed novel hybrid photocatalyst is discussed in detail.

  9. CpG Oligodeoxynucleotides Adsorbed onto Polylactide-Co-Glycolide Microparticles Improve the Immunogenicity and Protective Activity of the Licensed Anthrax Vaccine

    Xie, Hang; Gursel, Ihsan; Ivins, Bruce E.; Singh, Manmohan; O'Hagan, Derek T.; Ulmer, Jeffrey B.; Klinman, Dennis M.

    2005-01-01

    To reduce the biothreat posed by anthrax, efforts are under way to improve the protection afforded by vaccination. This work examines the ability of immunostimulatory CpG oligodeoxynucleotides (ODN) adsorbed onto cationic polylactide-co-glycolide (PLG) microparticles (CpG ODN-PLG) to accelerate and boost the protective immunity elicited by Anthrax Vaccine Adsorbed (AVA, the licensed human anthrax vaccine). The results indicate that coadministering CpG ODN-PLG with AVA induces a stronger and f...

  10. Cork-based activated carbons as supported adsorbent materials for trace level analysis of ibuprofen and clofibric acid in environmental and biological matrices.

    Neng, N R; Mestre, A S; Carvalho, A P; Nogueira, J M F

    2011-09-16

    In this contribution, powdered activated carbons (ACs) from cork waste were supported for bar adsorptive micro-extraction (BAμE), as novel adsorbent phases for the analysis of polar compounds. By combining this approach with liquid desorption followed by high performance liquid chromatography with diode array detection (BAμE(AC)-LD/HPLC-DAD), good analytical performance was achieved using clofibric acid (CLOF) and ibuprofen (IBU) model compounds in environmental and biological matrices. Assays performed on 30 mL water samples spiked at the 25.0 μg L(-1) level yielded recoveries around 80% for CLOF and 95% for IBU, under optimized experimental conditions. The ACs textural and surface chemistry properties were correlated with the results obtained. The analytical performance showed good precision (0.9922) from 1.0 to 600.0 μg L(-1). By using the standard addition methodology, the application of the present approach to environmental water and urine matrices allowed remarkable performance at the trace level. The proposed methodology proved to be a viable alternative for acidic pharmaceuticals analysis, showing to be easy to implement, reliable, sensitive and requiring low sample volume to monitor these priority compounds in environmental and biological matrices. PMID:21820664

  11. Transporting method for adsorbing tower and the adsorbing tower

    A cylindrical plastic bag is disposed to the upper surface of an adsorbing tower so as to surround a suspending piece. One opening of the bag is sealed, and other opening is secured in a sealed state to a bag holding portion disposed to glove box at a gate for the adsorbing tower box. The adsorbing tower is transported into the glove box, and after the completion of the operation of the adsorbing tower, the adsorbing tower is taken out in a state that the bag is restricted and sealed at a portion below the adsorbing tower. The bag may be made of a vinyl plastic, the bag holding portion may be a short-cylindrical protrusion, and may have an O-ring groove at the outer surface. Even if the adsorbing tower is heavy, the adsorbing tower can be carried out easily in a state where it is sealed gas tightly. (N.H.)

  12. Use of grape must as a binder to obtain activated carbon briquettes

    A. C. Deiana; D. L. Granados; L. M. Petkovic; M. F. Sardella; H. S. Silva

    2004-01-01

    The results of studies on briquetting activated-carbon-based adsorbent materials, prepared from raw materials from the region of Cuyo, Argentina, are reported in this article. Several steps were carried out to obtain activated-carbon briquettes from Eucalyptus camaldulensis Dehn wood. These steps included carbonization of wood to obtain char; blending of char and a novel binder, i.e., grape must; formation of cylinder-like briquettes by pressure; and activation of the resulting material. The ...

  13. Carbon dioxide conversion over carbon-based nanocatalysts.

    Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

    2013-07-01

    The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity. PMID:23901504

  14. Influence of mass recovery on the performance of a heat pipe type ammonia sorption refrigeration system using CaCl2/activated carbon as compound adsorbent

    The performance analyses of a sorption refrigeration system with different mass recovery processes are presented, in which compound adsorbent of CaCl2 and activated carbon is used to improve the mass and heat transfer performances of sorption bed. The heating, cooling and heat recovery processes between two sorption beds were performed by multifunction heat pipes without additional power consumption. The experimental Clapeyron diagrams showed that the cycles with mass recovery (MR), with heat and mass recoveries (HMR), and with mass and heat recoveries (MHR), have better thermodynamic performances when compared with the sorption cycle without mass recovery (MR0). The implementary order of mass recovery and heat recovery has strong influence on the efficacy of mass recovery while it has little influence on the efficacy of heat recovery. In sorption cycles with HMR and with MHR, the hot beds can be pre-cooled and cold beds can be pre-heated effectively during the switching process, and heat consumption from external heat source during desorption phase is thereby reduced. Mass recovery can enlarge cycled refrigerant mass due to the transfer of refrigerant gas between two sorption beds during mass recovery process. In comparison with sorption cycle with MR0, sorption cycles with MR, with HMR, and with MHR can generally improve the coefficient of performance (COP) and specific cooling power (SCP) by more than 20% and 16%, respectively. Especially, sorption cycle with MHR has the highest performance among different mass recovery processes due to the fact that MHR has the advantages of MR and HMR, and it can improve the COP by 46.7% when compared with the cycle with MR0

  15. Arsenic Removal from Water Using Various Adsorbents: Magnetic Ion Exchange Resins, Hydrous Ion Oxide Particles, Granular Ferric Hydroxide, Activated Alumina, Sulfur Modified Iron, and Iron Oxide-Coated Microsand

    Sinha, Shahnawaz

    2011-09-30

    The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic - rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of C eq = 10 μg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95 % .

  16. Theoretical Insight of Physical Adsorption for a Single Component Adsorbent + Adsorbate System: II. The Henry Region

    Chakraborty, Anutosh

    2009-07-07

    The Henry coefficients of a single component adsorbent + adsorbate system are calculated from experimentally measured adsorption isotherm data, from which the heat of adsorption at zero coverage is evaluated. The first part of the papers relates to the development of thermodynamic property surfaces for a single-component adsorbent + adsorbate system1 (Chakraborty, A.; Saha, B. B.; Ng, K. C.; Koyama, S.; Srinivasan, K. Langmuir 2009, 25, 2204). A thermodynamic framework is presented to capture the relationship between the specific surface area (Ai) and the energy factor, and the surface structural and the surface energy heterogeneity distribution factors are analyzed. Using the outlined approach, the maximum possible amount of adsorbate uptake has been evaluated and compared with experimental data. It is found that the adsorbents with higher specific surface areas tend to possess lower heat of adsorption (ΔH°) at the Henry regime. In this paper, we have established the definitive relation between Ai and ΔH° for (i) carbonaceous materials, metal organic frameworks (MOFs), carbon nanotubes, zeolites + hydrogen, and (ii) activated carbons + methane systems. The proposed theoretical framework of At and AH0 provides valuable guides for researchers in developing advanced porous adsorbents for methane and hydrogen uptake. © 2009 American Chemical Society.

  17. Insight into the adsorption of PPCPs by porous adsorbents: Effect of the properties of adsorbents and adsorbates.

    Zhu, Zengyin; Xie, Jiawen; Zhang, Mancheng; Zhou, Qing; Liu, Fuqiang

    2016-07-01

    Adsorption is an efficient method for removal of pharmaceuticals and personal care products (PPCPs). Magnetic resins are efficient adsorbents for water treatment and exhibit potential for PPCP removal. In this study, the magnetic hypercrosslinked resin Q100 was used for adsorption of PPCPs. The adsorption behavior of this resin was compared with those of two activated carbons, namely, Norit and F400D. Norit exhibited the fastest adsorption kinetics, followed by Q100. Norit featured a honeycomb shape and long-range ordered pore channels, which facilitated the diffusion of PPCPs. Moreover, the large average pore size of Q100 reduced diffusion resistance. The adsorbed amounts of 11 PPCPs on the three adsorbents increased with increasing adsorbate hydrophobicity. For Q100, a significant linear correlation was observed between the adsorption performance for PPCPs and hydrophobicity (logD value) of adsorbates (R(2) = 0.8951); as such, PPCPs with high logD values (>1.69) could be efficiently removed. Compared with those of Norit and F400D, the adsorption performance of Q100 was less affected by humic acid because of the dominant hydrophobic interaction. Furthermore, Q100 showed improved regeneration performance, which renders it promising for PPCP removal in practical applications. PMID:27131811

  18. Metal-loaded polystyrene-based activated carbons as DBT removal media via reactive adsorption

    Ovín Ania, María Concepción; Bandosz, T.J.

    2006-01-01

    [EN] To improve the desulfurization capability of activated carbons, new metal-loaded carbon-based sorbents containing sodium, cobalt, copper, and silver highly dispersed within the carbon matrix were prepared and tested at room temperature for dibenzothiophene (DBT) adsorption. The content of metals can be controlled by selective washing. The new adsorbents showed good adsorption capacities and selectivity towards DBT. The metals incorporated to the surface act not only as active sites for s...

  19. Ionogenic adsorbents based on local raw materials for radiation protection

    The successful management of uranium wastes and creating the conditions for effective rehabilitation activities require special adsorbents capable of holding on the surface complexes, including radioactive elements. Currently tested and have shown promising synthetic adsorbents based pitted apricot fruits and other fruit plants. This report presents data for the establishment of ionic type available adsorbents based on Tajikistan coal. As the base for the creation of this type of adsorbent were taken the coal of the 'Ziddi' deposits. As follows from our data on the chemical composition, the studied coals contain more than 20% of the ash. According to the available literature theses ashes contains various minerals compositions that can form the adsorbent's active surface. Thus, the model for this type of activated carbon can serve as a mixture of zeolite, ion exchange resins and activated carbon itself.

  20. The adsorption of water isotopomers on carbon adsorbents

    Adsorption isotherms in the range 50-80 Deg C were measured by gas chromatography, and isosteric adsorption heats of isotopomers of water were calculated in the range of low fillings at two activated carbons (Norit and FAS) with close volume of micropores (0.38 and 0.37 cm3/g), but various surface chemistry (AC Norit with hydrophilic surface and AC FAS with hydrophobic one). Adsorption of H2O and D2O at AC Norit exceeds adsorption at AC FAS at all equilibrium pressures. Adsorption isotherms of H2O and D2O at every adsorbents are close, but some excess of isotherms and adsorption heats of D2O as compared with H2O ones observes. It is connected with the differences in adsorbate-adsorbent and adsorbate-adsorbate interactions as well as with the structure of molecules of adsorbates

  1. Effect of γ-ray irradiation on adsorbents used in organic waste treatment

    Radioactive organic liquids (ROLs) are waste that require specific treatment. The Arvia process, developed by Arvia Technology Ltd., combines adsorption of organic material with electrochemical oxidation. This work focuses on the effect of γ-rays on the performance of adsorbents used in the Arvia process. Adsorbents used in this experimental study were provided by Arvia Technology Ltd. Specifically, Nyex 1000, a flake like carbon-based adsorbent, and Nyex 2105, a carbon-based adsorbent with a granular morphology. The γ-ray irradiation experiments were carried out using a Co-60 irradiator. The impact of irradiation on the microstructure, the adsorption capacity and the leaching of the 2 adsorbents were studied. The results show that no significant changes were detected in terms of structure, adsorption capacity and leaching of ions. The results of this paper are promising for the use of Nyex 1000 and Nyex 2105 as adsorbents in electrochemical waste treatment processes which involve high levels of γ-rays. The article is followed by the slides of the presentation

  2. Theoretical Insight of Physical Adsorption for a Single-Component Adsorbent + Adsorbate System: I. Thermodynamic Property Surfaces

    Chakraborty, Anutosh

    2009-02-17

    Thermodynamic property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical thermodynamics, thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations. They enable us to compute the entropy and enthalpy of the adsorbed phase, the isosteric heat of adsorption, specific heat capacity, and the adsorbed phase volume thoroughly. These equations are very simple and easy to handle for calculating the energetic performances of any adsorption system. We have shown here that the derived thermodynamic formulations fill up the information gap with respect to the state of adsorbed phase to dispel the confusion as to what is the actual state of the adsorbed phase. We have also discussed and established the temperature-entropy diagrams of (i) CaCl 2-in-silica gel + water system for cooling applications, and (ii) activated carbon (Maxsorb III) + methane system for gas storage. © Copyright 2009 American Chemical Society.

  3. Biological activities of organic compounds adsorbed onto ambient air particles: comparison between the cities of Teplice and Prague during the summer and winter seasons 2000-2001

    Binkova, Blanka; Cerna, Milena; Pastorkova, Anna; Jelinek, Richard; Benes, Ivan; Novak, Jiri; Sram, Radim J

    2003-04-09

    The capital of the Czech Republic, Prague, appears today to be one of the most polluted residential areas in the country, whereas air pollution in the Northern Bohemia region (the former 'Black Triangle Region') has substantially decreased during the last decade, especially with respect to the gaseous pollutant SO{sub 2}. This study evaluated the biological activities of complex mixtures of organic compounds adsorbed onto ambient air particles (PM10) collected during the summer and winter seasons of 2000-2001 at three monitoring sites - Teplice (TP), Prague-Smichov (PRG-SM) (city centre) and Prague-Libus (PRG-LB) (suburban area). The following short-term in vitro assays with strikingly different endpoints were used: a bacterial mutagenicity test using the Salmonella typhimurium tester strain TA98 and YG1041, an acellular assay (CT DNA) combined with {sup 32}P-postlabelling to evaluate DNA adduct-forming potency and the chick embryotoxicity screening test (CHEST). The results of the mutagenicity test with the YG1041 strain, the acellular genotoxicity (DNA adducts) and the embryotoxicity tests responded to the amount of eight carcinogenic polycyclic aromatic hydrocarbons (PAHs) analysed in the EOM (dichloromethane extractable organic matter) samples tested. Nevertheless, the biological effects of the EOM did not differ between locations. The highest biological activity of the ambient air in terms of organic compounds associated with particles (per unit volume of air) was seen in the Prague city centre during both summer and winter seasons. At this location, B[a]P concentration ranged from 0.1 to 8.9 ng/m{sup 3} (mean 0.3 and 3.6 ng/m{sup 3} for summer and winter seasons, respectively), 13 PAHs ranged from 11 to 343 ng/m{sup 3} (mean 52 and 160 ng/m{sup 3} for summer and winter seasons, respectively). Generally, using in vitro tests, higher ambient air activity was found in the winter season as compared with the summer season at all three monitoring sites

  4. Thermodynamic study of fatty acids adsorption on different adsorbents

    This work has as objective the study about the adsorption behavior of fatty acids (acetic, propionic, and butyric) on activated carbon and on modified and unmodified montmorillonite clays as a function of temperature and initial concentration of the adsorbate, through adsorption isotherms and their thermodynamic parameters (ΔG, ΔH, and ΔS). The activated carbon presented a higher adsorption capacity due to its relatively large surface area, compared to others adsorbents. The polar characteristic of fatty acids decreased with the increase in the length of non-polar hydrocarbon chain, improving the affinity between the activated carbon (non-polar adsorbent) and the acids. The adsorption capacity of modified montmorillonite (polar adsorbent) was favored due to the presence of the organic cation among its layers, which make the surface more hydrophobic and organophilic when compared to the unmodified montmorillonite surface. The amount of fatty acids adsorbed in the adsorbents surface increased with the concentration, at constant temperature, and decreased with the increase of temperature, at constant concentration. The amount of fatty acids adsorbed in the three adsorbents was related to the surface area and polarity of the adsorbent, concentration and solubility of the adsorbate and temperature of the solution. The negative values of ΔG and ΔH showed that the adsorption on activated carbon and on modified and unmodified montmorillonite clays was a spontaneous and an exothermic process. The decrease in the values of ΔG, with the increase of temperature, demonstrated that the adsorption was benefited by the high temperature and the positive values of ΔS showed that the fatty acids molecules were in a more randomic condition in the adsorbed state than in solution. The experimental results obtained at the temperatures of (298, 303, 313, and 323) K showed that experimental data were well represented by the Langmuir and Freundlich isotherms models

  5. Occurrence of an Affinity Site apart from the Active Site on the Raw-Starch-Digesting but Non-Raw-Starch-Adsorbable Bacillus subtilis 65 α-Amylase

    Hayashida, Shinsaku; Teramoto, Yuji; Inoue, Takehiro; Mitsuiki, Shinji

    1990-01-01

    α-Cyclodextrin specifically inhibited raw starch digestion by Bacillus subtilis 65 α-amylase. The raw starch digestibility and α-cyclodextrin-Sepharose 6B adsorbability of this α-amylase were simultaneously lost when the specific domain corresponding to the affinity site essential for raw starch digestion was deleted by proteolysis. Occurrence of the affinity site on raw-starch-digesting enzymes was proven also with bacterial amylase.

  6. Use of cyclic voltammetry and electrochemical impedance spectroscopy for determination of active surface area of modified carbon-based electrodes; Uso da voltametria ciclica e da espectroscopia de impedancia eletroquimica na determinacao da area superficial ativa de eletrodos modificados a base de carbono

    Souza, Leticia Lopes de

    2011-07-01

    Carbon-based electrodes as well the ion exchange electrodes among others have been applied mainly in the treatment of industrial effluents and radioactive wastes. Carbon is also used in fuel cells as substrate for the electrocatalysts, having high surface area which surpasses its geometric area. The knowledge of the total active area is important for the determination of operating conditions of an electrochemical cell with respect to the currents to be applied (current density). In this study it was used two techniques to determine the electrochemical active surface area of glassy carbon, electrodes and ion exchange electrodes: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The experiments were carried out with KNO{sub 3} 0.1 mol.L{sup -1} solutions in a three-electrode electrochemical cell: carbon-based working electrode, platinum auxiliary electrode and Ag/AgCl reference electrode. The glassy carbon and porous carbon electrodes with geometric areas of 3.14 x 10{sup -2} and 2.83 X 10{sup -1} cm{sup 2}, respectively, were used. The ion exchange electrode was prepared by mixing graphite, carbon, ion exchange resin and a binder, and this mixture was applied in three layers on carbon felt, using a geometric area of 1.0 cm{sup 2} during the experiments. The capacitance (Cd) of the materials was determined by EIS using Bode diagrams. The value of 172 {mu}F.cm{sup -2} found for the glassy carbon is consistent with the literature data ({approx} 200 {mu}F.cm'-{sup 2}). By VC, varying the scan rate from 0.2 to 2.0 mV.s-1, the capacitance CdS (S = active surface area) in the region of the electric double layer (EDL) of each material was determined. By EIS, the values of C{sub d}, 3.0 x 10{sup -5} {mu}F.cm'-{sup 2} and 11 x 10{sup 3} {mu}F.cm-2, were found for the porous carbon and ion exchange electrodes, respectively, which allowed the determination of active surface areas as 3.73 x 106 cm{sup 2} and 4.72 cm{sup 2}. To sum up, the

  7. High performance Mo adsorbent PZC

    Anon.

    1998-10-01

    We have developed Mo adsorbents for natural Mo(n, {gamma}){sup 99}Mo-{sup 99m}Tc generator. Among them, we called the highest performance adsorbent PZC that could adsorb about 250 mg-Mo/g. In this report, we will show the structure, adsorption mechanism of Mo, and the other useful properties of PZC when you carry out the examination of Mo adsorption and elution of {sup 99m}Tc. (author)

  8. Filter-adsorber aging assessment

    An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission's (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period

  9. Characterising electrospun nanofibre adsorbents for bioprocessing

    Dods, S. R.

    2016-01-01

    Biopharmaceutical manufacturing is one of largest sectors in the world and purification steps are expensive. Packed-bed resins are widely used, but are limited by diffusion mass transfer. Convective mass transfer media offer improved productivities using high flowrates. Electrospun nanofibres are a non-woven with an open structure and high surface area. Cellulose acetate was electrospun into reproducible adsorbents and activation methodologies were evaluated. Aldehyde activation caused degrad...

  10. BAHAN PENYERAP KMnO4 DAN ASAM L-ASKORBAT DALAM PENGEMASAN AKTIF (ACTIVE PACKAGING UNTUK MEMPERPANJANG MASA SIMPAN DAN MEMPERTAHANKAN MUTU BUAH DUKU (Lansium domesticum Corr. [Adsorbers for KMnO4 and L-Ascorbic Acid in the Active Packaging to Prolong the Shelve-Life and Maintain the Quality of Lanzone (Lansium domesticum Corr. Fruits

    Soesiladi E Widodo

    2005-08-01

    Full Text Available To develop an active packaging of lanzone (Lansium domisticum Corr. Fruits, KmnO4 as an ethylene scavenger and L-ascorbic acid as an oxygent scavenger were inserted into packaging. As direct contact of KmnO4 with agricultural product was not recommended and due to the liquid characteristic of both scavenger was carried out. This research was aimed at finding out the best adsorbers for KmnO4, L-ascorbic acid, and their combination in an active packaging to prolog the shelve-life and to maintain the quality of lanzone fruits. The result showed that 1 among the four adsorbers tested, pumice could was the best alternative as a KmnO4 or L-ascorbic acid adsorbers, and 2 spon and pumice were the best alternative adsorber for the combination of KmnO4 or L-ascorbic acid. Both adsorber were effective in prolonging the shelve-live (8-11 days longer than with out packaging and as good as using silica gel and vermiculite and maintaining the quality of lanzone fruits.

  11. Physico-chemical characteristics of activated carbons based on a copolymer of furfural and mineral raw materials of the Republic of Kazakhstan and their application in extracting gold from industrial solutions

    Kanagat Kishibayev

    2013-09-01

    Full Text Available Activated carbons are widely used in different industries for cleaning a variety of natural objects from of technogenic pollutants. In the article presents the results of physico-chemical investigations of activated carbons. The investigations on the sorption of gold in cyanide solutions activated sorbent based on furfural and sorbent based on shungit.

  12. Substrate-adsorbate coupling in CO-adsorbed copper

    Lewis, S P; Lewis, Steven P.; Rappe, Andrew M.

    1996-01-01

    The vibrational properties of carbon monoxide adsorbed to the copper (100) surface are explored within density functional theory. Atoms of the substrate and adsorbate are treated on an equal footing in order to examine the effect of substrate--adsorbate coupling. This coupling is found to have a significant effect on the vibrational modes, particularly the in-plane frustrated translation, which mixes strongly with substrate phonons and broadens into a resonance. The predicted lifetime due to this harmonic decay mechanism is in excellent quantitative agreement with experiment.

  13. Removal of acutely hazardous pharmaceuticals from water using multi-template imprinted polymer adsorbent.

    Venkatesh, Avinash; Chopra, Nikita; Krupadam, Reddithota J

    2014-05-01

    Molecularly imprinted polymer adsorbent has been prepared to remove a group of recalcitrant and acutely hazardous (p-type) chemicals from water and wastewaters. The polymer adsorbent exhibited twofold higher adsorption capacity than the commercially used polystyrene divinylbenzene resin (XAD) and powdered activated carbon adsorbents. Higher adsorption capacity of the polymer adsorbent was explained on the basis of high specific surface area formed during molecular imprinting process. Freundlich isotherms drawn showed that the adsorption of p-type chemicals onto polymer adsorbent was kinetically faster than the other reference adsorbents. Matrix effect on adsorption of p-type chemicals was minimal, and also polymer adsorbent was amenable to regeneration by washing with water/methanol (3:1, v/v) solution. The polymer adsorbent was unaltered in its adsorption capacity up to 10 cycles of adsorption and desorption, which will be more desirable in cost reduction of treatment compared with single-time-use activated carbon. PMID:24499987

  14. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    Zhao, Yunfeng

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

  15. Study of plutonium adsorption by fibrous adsorbent

    Japan Atomic Energy Research Institute and Unitika Ltd. have been conducting, under a joint effort, development of an inorganic fibrous adsorbent (FAC), which is capable of adsorbing plutonium (Pu) contained in radioactive liquid waste and which is also able to contribute to reduction of the volume of α-waste by incineration. The fibrous adsorbent constitutes fibrous activated carbon of coal tar pitch derivative and has the following characteristics: (1) It has a large surface area. (2) Carbon constitutes more than 90% in the adsorbent; it is physically and chemically stable as an inorganic adsorbent; it is easy to be incinerated. (3) It is easy to be formed or molded into different shapes such as cartridges, and handling of the material is extremely easy. By using various kinds of Pu solution, we carried out tests and evaluations on the equilibrium adsorption quantity of Pu by the fibrous adsorbent, the adsorption property of the material by flow-through column test and the incineration property of the material in the cold test. The tests show that: (1) adsorption of Pu is the best with 0.8∼0.9 mg-Pu/g-FAC when the concentration of nitric acid is near 1 M; (2) as the concentration of nitric acid is increased, its adsorption capacity becomes poorer; (3) when Pu coexists with Uranium (U), the adsorption capacity becomes slightly inferior; (4) in the flow-through column test, no breakthrough of Pu was observed until the volume of Pu liquid becomes about 3 times larger than the column volume; (5) in the incineration tests in the cold test using a laboratory scale incinerator, no flying of particles or soot was observed; and (6) it is possible to get good incineration at 500 ∼ 600 degrees C. The above results show that, by using the fibrous adsorbent, it became possible to remove Pu from radioactive liquid waste by adsorption, to reduce the volume only to residual ash by incineration, and to reduce substantially the volume of α-waste

  16. MODIFICATION OF CARBONACEOUS ADSORBENTS WITH MANGANESE COMPOUNDS

    Irina Ginsari; Larisa Postolachi; Vasile Rusu; Oleg Petuhov; Tatiana Goreacioc; Tudor Lupascu; Raisa Nastas

    2015-01-01

    Four series of samples containing manganese supported carbonaceous adsorbents were prepared. Obtained results reveal the importance of surface chemistry of carbonaceous adsorbents on the manganese loading.

  17. Influence of electrode preparation on the electrochemical behaviour of carbon-based supercapacitors

    Ruiz Ruiz, Vanesa; Blanco Rodríguez, Clara; Granda Ferreira, Marcos; Menéndez López, Rosa María; Santamaría Ramírez, Ricardo

    2007-01-01

    [EN] This work investigates the influence of electrode preparation on the electrochemical behaviour of carbon-based supercapacitors. Studies were performed using the same activated carbon and polymer polyvynilidene fluoride (PVDF) in the same proportions (10 wt.% PVDF). Only the way in which these components were mixed was modified. The procedure for mixing the activated carbon and the polymer has a significant influence on the electrochemical behaviour of the electrode used in a supercapacit...

  18. Recent advances in carbon-based dots for electroanalysis.

    Yulong, Ying; Xinsheng, Peng

    2016-04-25

    Carbon-based dots represent a new type of quantum dot with unique and well-defined properties owing to their quantum confinement and edge effects, which are widely employed in sensing, light-emitting diodes, nanomedicine, photocatalysis, electrocatalysis, bioimaging, etc. In this review, we update the latest research results of carbon-based dots in this rapidly evolving field of electroanalysis, place emphases on their applications as sensors and give future perspectives for developing more smart sensors. PMID:26797087

  19. Polymer composite material structures comprising carbon based conductive loads

    Jérôme, Robert; Pagnoulle, Christophe; Detrembleur, Christophe; Thomassin, Jean-Michel; Huynen, Isabelle; Bailly, Christian; Bednarz, Luikasz; Daussin, Raphaël; Saib, Aimad; Baudouin, Anne-Christine; Laloyaux, Xavier

    2007-01-01

    The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 wt % to 6 wt % carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loa...

  20. Polymer composite material structures comprising carbon based conductive loads

    Jérôme, Robert; Pagnoulle, Christophe; Detrembleur, Christophe; Thomassin, Jean-Michel; Huynen, Isabelle; Bailly, Christian; Bednarz, Lucasz; Daussin, Raphaël; Saib, Aimad

    2006-01-01

    The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 to 6 wt% carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loads. Th...

  1. Cryogenic adsorber design in a helium refrigeration system

    Hu, Zhongjun; Zhang, Ning; Li, Zhengyu; Li, Q.

    2012-06-01

    The cryogenic adsorber is specially designed to eliminate impurities in gaseous helium such as O2, and N2 which is normally difficult to remove, based on the reversible cryotrapping of impurities on an activated carbon bed. The coconut shell activated carbon is adopted because of its developed micropore structure and specific surface area. This activated carbon adsorption is mostly determined by the micropore structure, and the adsorption rate of impurities is inversely proportional to the square of the particle sizes. The active carbon absorber's maximum permissible flow velocity is 0.25 m/s. When the gas flow velocity increases, the adsorption diffusion rate of the adsorbent is reduced, because an increase in the magnitude of the velocity resulted in a reduced amount of heat transfer to a unit volume of impure gas. According to the numerical simulation of N2 adsorption dynamics, the appropriate void tower link speed and the saturated adsorption capacity are determined. Then the diameter and height of the adsorber are designed. The mass transfer length should be taken into account in the adsorber height design. The pressure decrease is also calculated. The important factors that influence the adsorber pressure decrease are the void tower speed, the adsorbed layer height, and the active carbon particle shape and size.

  2. TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

    RAISA NASTAS

    2012-03-01

    Full Text Available Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the type of impregnated heteroatom (N, O, or metals (Fe, Cu, Ni, on removal of hydrogen sulfide species and nitrite ions have been researched. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous ground waters. Comparative analysis of carbonaceous adsorbents reveals the importance of surface chemistry for oxidation of nitrite ions.

  3. Green Adsorbents for Wastewaters: A Critical Review

    George Z. Kyzas

    2014-01-01

    Full Text Available One of the most serious environmental problems is the existence of hazardous and toxic pollutants in industrial wastewaters. The major hindrance is the simultaneous existence of many/different types of pollutants as (i dyes; (ii heavy metals; (iii phenols; (iv pesticides and (v pharmaceuticals. Adsorption is considered to be one of the most promising techniques for wastewater treatment over the last decades. The economic crisis of the 2000s led researchers to turn their interest in adsorbent materials with lower cost. In this review article, a new term will be introduced, which is called “green adsorption”. Under this term, it is meant the low-cost materials originated from: (i agricultural sources and by-products (fruits, vegetables, foods; (ii agricultural residues and wastes; (iii low-cost sources from which most complex adsorbents will be produced (i.e., activated carbons after pyrolysis of agricultural sources. These “green adsorbents” are expected to be inferior (regarding their adsorption capacity to the super-adsorbents of previous literature (complex materials as modified chitosans, activated carbons, structurally-complex inorganic composite materials etc., but their cost-potential makes them competitive. This review is a critical approach to green adsorption, discussing many different (maybe in some occasions doubtful topics such as: (i adsorption capacity; (ii kinetic modeling (given the ultimate target to scale up the batch experimental data to fixed-bed column calculations for designing/optimizing commercial processes and (iii critical techno-economical data of green adsorption processes in order to scale-up experiments (from lab to industry with economic analysis and perspectives of the use of green adsorbents.

  4. Krypton retention on solid adsorbents

    Radioactive krypton-85 is released to the atmosphere in the off-gas from nuclear reprocessing plants. Three main methods have been suggested for removal of krypton from off-gas streams: cryogenic distillation; fluorocarbon absorption; and adsorption on solid sorbents. Use of solid adsorbents is the least developed of these methods, but offers the potential advantages of enhanced safety and lower operating costs. An experimental laboratory program was developed that will be used to investigate systematically many solid adsorbents (such as zeolites, i.e., mordenites) for trapping krypton in air. The objective of this investigation is to find an adsorbent that is more economical than silver-exchanged mordenite. Various physical and chemical characteristics such as adsorption isotherms, decontamination factors, co-adsorption, regeneration, and the mechanism and kinetics of noble gas adsorption were used to characterize the adsorbents. In the experimental program, a gas chromatograph using a helium ionization detector was used to measure the krypton in air before and after the adsorbent bed. This method can determine directly decontamination factors greater than 100

  5. Electric field cancellation on quartz: a Rb adsorbate induced negative electron affinity surface

    Sedlacek, J A; Rittenhouse, S T; Weck, P F; Sadeghpour, H R; Shaffer, J P

    2015-01-01

    We investigate the (0001) surface of single crystal quartz with a submonolayer of Rb adsorbates. Using Rydberg atom electromagnetically induced transparency, we investigate the electric fields resulting from Rb adsorbed on the quartz surface, and measure the activation energy of the Rb adsorbates. We show that the adsorbed Rb induces a negative electron affinity (NEA) on the quartz surface. The NEA surface allows low energy electrons to bind to the surface and cancel the electric field from the Rb adsorbates. Our results are important for integrating Rydberg atoms into hybrid quantum systems and the fundamental study of atom-surface interactions, as well as applications for electrons bound to a 2D surface.

  6. Electric Field Cancellation on Quartz by Rb Adsorbate-Induced Negative Electron Affinity

    Sedlacek, J. A.; Kim, E.; Rittenhouse, S. T.; Weck, P. F.; Sadeghpour, H. R.; Shaffer, J. P.

    2016-04-01

    We investigate the (0001) surface of single crystal quartz with a submonolayer of Rb adsorbates. Using Rydberg atom electromagnetically induced transparency, we investigate the electric fields resulting from Rb adsorbed on the quartz surface, and measure the activation energy of the Rb adsorbates. We show that the adsorbed Rb induces negative electron affinity (NEA) on the quartz surface. The NEA surface allows low energy electrons to bind to the surface and cancel the electric field from the Rb adsorbates. Our results will be important for integrating Rydberg atoms into hybrid quantum systems, as fundamental probes of atom-surface interactions, and for studies of 2D electron gases bound to surfaces.

  7. Feasibility study of MTBE removal in biological activated carbon adsorber%生物活性炭吸附工艺去除地下水中甲基叔丁基醚的可行性研究

    李冰璟; 胡娟; 左军; 黄流雅; 杨丞磊; 张巍; 应维琪

    2011-01-01

    Methyl tert-butyl ether (MTBE) is a common gasoline additive; it has become a groundwater pollutant in many countries. Granular activated carbon (GAC) adsorption treatment is not cost effective for removing MTBE because it is not well adsorbed on activated carbon. Employing highly acclimated bacteria to degrade adsorbed MTBE to extend the service period of the GAC adsorber will make it more cost effective. Using the conventional inoculation method of circulating the seeding solution of MTBE degraders came with the spent GAC sample from a biological GAC treatment system of a MTBE remediation site to treat a high MTBE influent (30. 0 mg/L,simulating a newly contaminated groundwater) ,the effluent samples of inoculated coal and coconut GAC columns were nearly the same as those of the non-innoculated columns because the slow growing MTBE degraders were not easily retained and the low MTBE degradation rate. After a start-up period of less than two months,the small GAC columns filled with new coconut GAC on top of the same spent GAC became effective biological activated carbon (BAC) systems capable of removing >40% MTBE from the influent; a small dose of hydrogen peroxide provided the essential dissolved oxygen to sustain aerobic degradation of MTBE in the adsorbers; adding peroxide to the nfluents of two serial adsorbers is desirable in treating newly contaminated groundwater. When MTBE concentration of the influent declined steadily, the BAC capability prevented the sudden rise of MTBE concentration in the effluent and helped to restore the long term treatment effectiveness. Treating the low MTBE influent (1.0 mg/L),the five BAC columns of different spent GAC amount and operating conditions all demonstrated outstanding treatment performance in the 165 days of operation with stable MTBE removals of >97% and cumulative removal of >282% of the theoretical adsorptive capacity of the columns. The research has established an effective inoculation method to enable

  8. Carbon-Based Compounds and Exobiology

    Kerridge, John; DesMarais, David; Khanna, R. K.; Mancinelli, Rocco; McDonald, Gene; diBrozollo, Fillipo Radicati; Wdowiak, Tom

    1996-01-01

    The Committee for Planetary and Lunar Explorations (COMPLEX) posed questions related to exobiological exploration of Mars and the possibility of a population of carbonaceous materials in cometary nuclei to be addressed by future space missions. The scientific objectives for such missions are translated into a series of measurements and/or observations to be performed by Martian landers. These are: (1) A detailed mineralogical, chemical, and textural assessment of rock diversity at a landing site; (2) Chemical characterization of the materials at a local site; (3) Abundance of Hydrogen at any accessible sites; (4) Identification of specific minerals that would be diagnostic of aqueous processes; (5) Textual examination of lithologies thought to be formed by aqueous activity; (6) Search for minerals that might have been produced as a result of biological processes; (7) Mapping the distribution, in three dimensions, of the oxidant(s) identified on the Martian surface by the Viking mission; (8) Definition of the local chemical environment; (9) Determination of stable-isotopic ratios for the biogenic elements in surface mineral deposits; (10) Quantitative analysis of organic (non-carbonate) carbon; (11) Elemental and isotopic composition of bulk organic material; (12) Search for specific organic compounds that would yield information about synthetic mechanisms, in the case of prebiotic evolution, and about possible bio-markers, in the case of extinct or extant life; (13) and Coring, sampling, and detection of entrained gases and cosmic-ray induced reaction products at the polar ice cap. A discussion of measurements and/or observations required for cometary landers is included as well.

  9. Effect of Adsorbent and Ion Exchange Resin Applications on Total Phenolic Content and Antioxidant Activity of White and Red Grape Juices

    Akbulut, Mehmet

    2015-01-01

    In this study activated carbon, Dowex® 50Wx8-100 and Amberlite® XAD-16 were applied to white and red grape juices to determine effects on total phenolic and antioxidant activity of juices. Total phenolic and antioxidant activity (DPPH, ABTS and FRAP) analyses were performed in control and resin applied grape juices. Total phenolic content of white grape juice was found as 2.28 g GAE/kg dry weight. Total phenolic contents of white grape juices were decreased to 14.00, 14.00 and 23.24%, respect...

  10. Development of an adsorbent for both cesium and strontium

    Described is the development of the adsorbent in the title at the process of developing the agent to adsorb each element. For cooling the reactors injured by the Fukushima Nuclear Power Plant Accident by the earthquake and tsunami on the day before (Mar. 11, 2011), fresh/ sea water is supplied in the reactor and flows out contaminated with radioactive elements in the turbine building and then in the treatment plant to remove oil and cesium for re-circulation to the reactor. Water from the plant still contains radioisotopes derived from fission, like 90Sr/90Y at 1.2 x 108 Bq/L and 137Cs/137mBa at 6.1 x 103 Bq/L, and from activation of reactor materials. Before the plant, the water contains 137Cs at the level as high as 4.1 x 107 Bq/L. Authors have examined various agents to adsorb 90Sr and 137Cs with a measure of partition coefficient Kd (L of the artificial sea water/kg) and have come to find out the adsorbent in the title: it is derived from the Cs-adsorbing crystalized silico-titanate (CST). The adsorbent is obtainable by surface treatment of CST with NaOH and has high Kds of >1 x 103 and >1 x 104 L/kg for Sr and Cs, respectively, while other ordinary adsorbents' Kds are: artificial zeolite 1-10 x 102/1-10 x 101 for Sr/Cs, respectively; natural one 0.1-10 x 101/1-10 x 102; ferrocyanide 0.1-10 x 101/1-10 x 104, and CST 1 x 101/>1 x 104. When 1 m3 of the present adsorbent is used, >99% of Cs and Sr can be removable in >3,000 m3 of contaminated water, suggesting its usefulness for dealing with water after the Accident. (T.T.)

  11. Indigenization Research of Activated Carbon Adsorbent for Radioiodine Waste Gas Treatment System at a Nuclear Plant%某核电站放射性碘废气处理系统活性炭吸附剂测试

    张计荣; 侯建荣; 沈大鹏; 李永国; 张群; 高琳锋

    2013-01-01

    For the purpose of the indigenization of activated carbon adsorbent at a nuclear plant ,two types of activated carbons were mixed at the optimum rate ,through impregnating and drying .The onsite testing results show that the resistance of the mixed activated carbon is ≤3 400 Pa and the efficiency of cleaning radioactive methyl iodine is≥98% .The other performances meet the needs of engineering .%为实现某核电站放射性碘废气处理系统活性炭吸附剂的国产化,选取国产圆柱状煤质活性炭与椰壳活性炭,以一定比例混合,浸渍烘干,装填到碘废气处理系统中,现场试验结果表明其阻力≤3400 Pa、除碘效率≥98%,性能满足工程使用要求。

  12. Protein purification using magnetic adsorbent particles

    Franzreb, M; Siemann-Herzberg, M.; Hobley, Timothy John;

    2006-01-01

    The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence...

  13. Black Sprayable Molecular Adsorber Coating Project

    National Aeronautics and Space Administration — This novel molecular adsorber coating would alleviate the size, weight, and complexity issues of traditional molecular adsorber puck.  A flexible tape version...

  14. Utility of adsorbents in the purification of drinking water: a review of characterization, efficiency and safety evaluation of various adsorbents.

    Dubey, Shashi Prabha; Gopal, Krishna; Bersillon, J L

    2009-05-01

    Clean drinking water is one of the implicit requisites fora healthy human population. However the growing industrialization and extensive use of chemicals for various concerns, has increased the burden of unwanted pollutants in the drinking water of developing countries like India. The entry of potentially hazardous substances into the biota has been magnifying day by day. In the absence of a possible stoppage of these, otherwise, useful chemicals, the only way to maintain safer water bodies is to develop efficient purifying technologies. One such immensely beneficial procedure that has been in use is that of purification of water using 'adsorbents'. Indigenous minerals and natural plants products have potential for removing many pollutants viz. fluoride, arsenic, nitrate, heavy metals, pesticides as well as trihalomethanes. Adsorbents which are derived from carbon, alumina, zeolite, clay minerals, iron ores, industrial by products, and natural products viz. parts of the plants, herbs and algal biomass offer promising potential of removal. In the recent years attention has been paid to develop process involving screening/pretreatment/activation/impregnation using alkalies, acids, alum, lime, manganese dioxide, ferric chloride and other chemicals which are found to enhance their adsorbing efficiency. Chemical characterization of these adsorbents recapitulates the mechanism of the process. It is imperative to observe that capacities of the adsorbents may vary depending on the characteristics, chemical modifications and concentration of the individual adsorbent. Removal kinetics is found to be based on the experimental conditions viz. pH, concentration of the adsorbate, quantity of the adsorbent and temperature. It is suggested that isotherm model is suitable tool to assess the adsorption capacities in batch and column modes. Safety evaluation and risk assessment of the process/products may be useful to provide guidelines for its sustainable disposal. PMID:20120453

  15. Isothermal composite adsorbent. Part I: Thermal characterisation

    Adsorption and desorption are respectively exo and endothermic phenomena leading to significant temperature changes in adsorption columns. Enhanced efficiency of a sorption process could be obtained under isothermal conditions, either for gas storage, purification or separation applications. The heat transfer within the adsorbent beds can be managed in situ, using thermal energy storage material: a phase change materials (PCM) for example. The thermal behaviour of a mixture of activated carbon and PCM during CO2 adsorption has been studied. The thermal characteristics of the involved materials have been determined and experiments carried out to highlight the positive effect of the PCM to reduce the CO2 adsorption heat effects on an activated carbon bed. Calorimetry was the technique used for all the thermal characterisations. It appears that the heat effects induced by CO2 adsorption are reduced by the presence of the PCM together with the adsorbent. The endothermic effect of fusion balances the heat effect of adsorption and significantly reduces the temperature changes

  16. Performance of Laterite Soil Grains as Adsorbent in the Removal of Chromium

    Syama I J; Arun Kumar Thalla; Manu D S

    2015-01-01

    The present study aims to examine the efficiency of laterite grains (LG) and acid activated laterite grains (AALG) as an adsorbent for removal hexavalent chromium and ferric ion from synthetic wastewater, under laboratory conditions. Adsorption of hexavalent chromium and ferric ion from synthetic wastewater is examined by batch and column studies wherein it is found to be dependent on pH, Contact time, adsorbent dosage and initial adsorbate concentration. Percentage removal enhances with the ...

  17. Waste Material Adsorbents for Zinc Removal from Wastewater: A Comprehensive Review

    Zwain, Haider M.; Mohammadtaghi Vakili; Irvan Dahlan

    2014-01-01

    This review examines a variety of adsorbents and discusses mechanisms, modification methods, recovery and regeneration, and commercial applications. A summary of available researches has been composed by a wide range of potentially low-cost modified adsorbents including activated carbon, natural source adsorbents (clay, bentonite, zeolite, etc.), biosorbents (black gram husk, sugar-beet pectin gels, citrus peels, banana and orange peels, carrot residues, cassava waste, algae, algal, marine gr...

  18. Effect of co-existing ions during the preparation of alumina by electrolysis with aluminum soluble electrodes: Structure and defluoridation activity of electro-synthesized adsorbents

    Tchomgui-Kamga, Eric, E-mail: etchomgui@yahoo.fr [UMR CNRS n°6226 Institut des Sciences Chimiques de Rennes, ENSCR, Avenue du Général Leclerc, CS 50837 - 35708 Rennes Cedex 7 (France); Laboratoire de Chimie Analytique, Faculté des Sciences, Université de Yaoundé-I, BP 812 Yaoundé (Cameroon); Audebrand, Nathalie, E-mail: nathalie.audebrand@univ-rennes1.fr [UMR CNRS n°6226 Institut des Sciences Chimiques de Rennes, Université de Rennes-1, Avenue du Général Leclerc, 35042 Rennes Cedex (France); Darchen, André, E-mail: Andre.Darchen@ensc-rennes.fr [UMR CNRS n°6226 Institut des Sciences Chimiques de Rennes, ENSCR, Avenue du Général Leclerc, CS 50837 - 35708 Rennes Cedex 7 (France)

    2013-06-15

    Highlights: • pH increases during electrocoagulation with aluminum electrodes are rationalized. •Composition of electrogenerated aluminas is dependent upon the electrolyte used. • All the electrogenerated aluminas contained nanoparticles of boehmite AlOOH. • The defluoridation activity of the aluminas was dependent upon the electrolyte used. -- Abstract: The electrochemical dissolution of aluminum was carried out to prepare hydrated aluminas which were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), chemical titrations and defluoridation activities. Aluminas were obtained at controlled pH depending upon the counter cations of the electrolyte. A boehmite AlOOH phase was isolated mainly in ammonium solution, while aluminas synthesized in the other media contained a mixture of phases, usually both boehmite and bayerite γ-Al(OH){sub 3}. All the boehmite phases contained nano-crystallites of less than 3 nm. Batch defluoridation experiments revealed a second influence of the original electrolyte. Aluminas were very effective in defluoridation with abatement rates of 99.5%, 98.5% and 97.3% from neutral fluoride solution at 10 mg L{sup −1} when they were prepared in solution of (NH{sub 4}){sub 2}SO{sub 4}, (NH{sub 4})HCO{sub 2} and NH{sub 4}Cl, respectively. The maximum fluoride capacities were 46.94; 10.25 and 12.18 mg g{sup −1} for aluminas prepared in solution of (NH{sub 4}){sub 2}SO{sub 4}; (NH{sub 4})HCO{sub 2} and NH{sub 4}Cl, respectively. The amount of dissolved Al was found to be less than 0.19 mg L{sup −1} at neutral pH. These results show that a defluoridation with electro-synthesized aluminas would be more efficient and safe than a direct electrocoagulation.

  19. Effect of co-existing ions during the preparation of alumina by electrolysis with aluminum soluble electrodes: Structure and defluoridation activity of electro-synthesized adsorbents

    Highlights: • pH increases during electrocoagulation with aluminum electrodes are rationalized. •Composition of electrogenerated aluminas is dependent upon the electrolyte used. • All the electrogenerated aluminas contained nanoparticles of boehmite AlOOH. • The defluoridation activity of the aluminas was dependent upon the electrolyte used. -- Abstract: The electrochemical dissolution of aluminum was carried out to prepare hydrated aluminas which were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), chemical titrations and defluoridation activities. Aluminas were obtained at controlled pH depending upon the counter cations of the electrolyte. A boehmite AlOOH phase was isolated mainly in ammonium solution, while aluminas synthesized in the other media contained a mixture of phases, usually both boehmite and bayerite γ-Al(OH)3. All the boehmite phases contained nano-crystallites of less than 3 nm. Batch defluoridation experiments revealed a second influence of the original electrolyte. Aluminas were very effective in defluoridation with abatement rates of 99.5%, 98.5% and 97.3% from neutral fluoride solution at 10 mg L−1 when they were prepared in solution of (NH4)2SO4, (NH4)HCO2 and NH4Cl, respectively. The maximum fluoride capacities were 46.94; 10.25 and 12.18 mg g−1 for aluminas prepared in solution of (NH4)2SO4; (NH4)HCO2 and NH4Cl, respectively. The amount of dissolved Al was found to be less than 0.19 mg L−1 at neutral pH. These results show that a defluoridation with electro-synthesized aluminas would be more efficient and safe than a direct electrocoagulation

  20. Carbon-Based Fibrous EDLC Capacitors and Supercapacitors

    Lekakou, C.; O. Moudam; Markoulidis, F; Andrews, T.; J. F. Watts; Reed, G.T.

    2011-01-01

    This paper investigates electrochemical double-layer capacitors (EDLCs) including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF) and a multiwall carbon nanotube (CNT) electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance test...

  1. Irradiation behavior of carbon-based composite materials

    Consideration is given to the data on radiation changes of sizes and some properties of different carbon-based composite materials (carbon-graphite and graphite-graphite compositions; carbon-carbon composite materials with carbon reinforcing fibers; carbon-silicon compositions), irradiated by neutrons at 320-1700 k. It is shown that change of sizes is dictated by the type and the ratio of components, forming (or not forming) the reinforcing uniform frame. 22 refs.; 10 figs

  2. Application of bifunctional magnetic adsorbent to adsorb metal cations and anionic dyes in aqueous solution

    Lin, Ya-Fen [Department of Chemical and Materials Engineering, National I-Lan University, I-Lan 260, Taiwan (China); Chen, Hua-Wei [Department of Cosmetic Application and Management, St. Mary' s Medicine Nursing and Management College, I-Lan, Taiwan (China); Chien, Poh-Sun [Department of Environmental Engineering, National I-Lan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan (China); Chiou, Chyow-San, E-mail: cschiou@niu.edu.tw [Department of Environmental Engineering, National I-Lan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan (China); Liu, Cheng-Chung [Department of Environmental Engineering, National I-Lan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan (China)

    2011-01-30

    A magnetic adsorbent, amine-functionalized silica magnetite (NH{sub 2}/SiO{sub 2}/Fe{sub 3}O{sub 4}), has been synthesized to behave as an anionic or cationic adsorbent by adjusting the pH value of the aqueous solution to make amino groups protonic or neutral. NH{sub 2}/SiO{sub 2}/Fe{sub 3}O{sub 4} were used to adsorb copper ions (metal cation) and Reactive Black 5 (RB5, anionic dye) in an aqueous solution in a batch system, and the maximum adsorption were found to occur at pH 5.5 and 3.0, respectively. The adsorption equilibrium data were all fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg g{sup -1} for copper ions and of 217 mg g{sup -1} for RB5. A pseudo-second-order model also could best describe the adsorption kinetics, and the derived activation energy for copper ions and RB5 were 26.92 kJ mol{sup -1} and 12.06 kJ mol{sup -1}, respectively. The optimum conditions to desorb cationic and anionic adsorbates from NH{sub 2}/SiO{sub 2}/Fe{sub 3}O{sub 4} were provided by a solution with 0.1 M HNO{sub 3} for copper ions and with 0.05 M NaOH for RB5.

  3. Enhanced hydrogenation activity and diastereomeric interactions of methyl pyruvate co-adsorbed with R-1-(1-naphthyl)ethylamine on Pd(111).

    Mahapatra, Mausumi; Burkholder, Luke; Garvey, Michael; Bai, Yun; Saldin, Dilano K; Tysoe, Wilfred T

    2016-01-01

    Unmodified racemic sites on heterogeneous chiral catalysts reduce their overall enantioselectivity, but this effect is mitigated in the Orito reaction (methyl pyruvate (MP) hydrogenation to methyl lactate) by an increased hydrogenation reactivity. Here, this effect is explored on a R-1-(1-naphthyl)ethylamine (NEA)-modified Pd(111) model catalyst where temperature-programmed desorption experiments reveal that NEA accelerates the rates of both MP hydrogenation and H/D exchange. NEA+MP docking complexes are imaged using scanning tunnelling microscopy supplemented by density functional theory calculations to allow the most stable docking complexes to be identified. The results show that diastereomeric interactions between NEA and MP occur predominantly by binding of the C=C of the enol tautomer of MP to the surface, while simultaneously optimizing C=O····H2N hydrogen-bonding interactions. The combination of chiral-NEA driven diastereomeric docking with a tautomeric preference enhances the hydrogenation activity since C=C bonds hydrogenate more easily than C=O bonds thus providing a rationale for the catalytic observations. PMID:27488075

  4. Preparation and characterization of a novel adsorbent from Moringa oleifera leaf

    Bello, Olugbenga Solomon; Adegoke, Kayode Adesina; Akinyunni, Opeyemi Omowumi

    2015-10-01

    A new and novel adsorbent was obtained by impregnation of Moringa oleifera leaf in H2SO4 and NaOH, respectively. Prepared adsorbents were characterized using elemental analysis, FT-IR, SEM, TGA and EDX analyses, respectively. The effects of operational parameters, such as pH, moisture content, ash content, porosity and iodine number on these adsorbents were investigated and compared with those of commercial activated carbon (CAC). EDX results of acid activated M. oleifera leaf have the highest percentage of carbon by weight (69.40 %) and (76.11 %) by atom, respectively. Proximate analysis showed that the fixed carbon content of acid activated M. oleifera leaf (69.14 ± 0.01) was the highest of all adsorbents studied. Conclusively, the present investigation shows that acid activated M. oleifera leaf is a good alternative adsorbent that could be used in lieu of CAC for recovery of dyes and heavy metal from aqueous solutions and other separation techniques.

  5. Oil palm biomass-based adsorbents for the removal of water pollutants--a review.

    Ahmad, Tanweer; Rafatullah, Mohd; Ghazali, Arniza; Sulaiman, Othman; Hashim, Rokiah

    2011-07-01

    This article presents a review on the role of oil palm biomass (trunks, fronds, leaves, empty fruit bunches, shells, etc.) as adsorbents in the removal of water pollutants such as acid and basic dyes, heavy metals, phenolic compounds, various gaseous pollutants, and so on. Numerous studies on adsorption properties of various low-cost adsorbents, such as agricultural wastes and its based activated carbons, have been reported in recent years. Studies have shown that oil palm-based adsorbent, among the low-cost adsorbents mentioned, is the most promising adsorbent for removing water pollutants. Further, these bioadsorbents can be chemically modified for better efficiency and can undergo multiple reuses to enhance their applicability at an industrial scale. It is evident from a literature survey of more than 100 recent papers that low-cost adsorbents have demonstrated outstanding removal capabilities for various pollutants. The conclusion is been drawn from the reviewed literature, and suggestions for future research are proposed. PMID:21929380

  6. SYNTHESIS OF SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    XUMingcheng; XUMancai; 等

    2000-01-01

    Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization.The properties of the obtained adsorbent were also investigated in detail.The results showed that the water permeability could be improved by adding hydroxyl-contatining organic compound moiety into the adsorbent.The specific surface area and average pore diameter of these adsorbents increaswed while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.

  7. Agricultural By-products as Mercury Adsorbents in Gas Applications

    Increased emphasis on reduction of mercury emissions from coal fired electric power plans have resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents. The sorbents could be injected into the flue gas stream where is adsorbs the merc...

  8. Synergistic process design: Reducing drying energy consumption by optimal adsorbent selection

    Atuonwu, J.C.; Straten, van G.; Deventer, van H.C.; Boxtel, van A.J.B.

    2013-01-01

    This work analyzes the synergy between two complementary unit operations - adsorbent dehumidification and drying - and presents a mixed integer nonlinear programming approach to optimize energy performance in a two-stage system. Combined with active constraint analysis, the adsorbent properties that

  9. Utilization of Roselle charcoal as nitrate-nitrogen adsorbent

    Yimrattanabovorn, J.

    2006-11-01

    Full Text Available Recently, the attempts have been made by utilizing natural material as an adsorbent for wastewater treatment due to its low cost, low energy requirement and the fewer chemicals used. In this study, Roselle (Hibiscus sabdariffa L. var. altissima was prepared to use as a charcoal adsorbent in the treatment process. The nitrate-nitrogen adsorption capacities of Roselle charcoal with 2 different particle sizes, A (4.75- .30 mm and B (2.00-4.75 mm were measured and compared with an activated carbon (AC. The equilibrium data fitted well with the Freundlich Isotherm. The K values related to the capacity of adsorbent for nitratenitrogen of such charcoal studied were in the following orders: AC > B > A expressed as 0.0321, 0.0147 and 0.0071 respectively. In addition, activated carbon required less contact time to reach equilibrium than both of Roselle charcoal A and B. Although removal efficiency of activated carbon was higher than that of Roselle charcoal, Roselle charcoal is an interesting alternative adsorbent due to the lower cost of its production.

  10. Dissolved Air Flotation of arsenic adsorbent particles

    Santander, M.; Valderrama, L.

    2015-01-01

    The removal of arsenic from synthetic effluent was studied using the adsorbent particle flotation technique (APF) and dissolved air flotation (DAF). A sample of an iron mineral was used as adsorbent particles of arsenic, ferric chloride as coagulant, cationic polyacrylamide (NALCO 9808) as flocculants, and sodium oleate as collector. Adsorption studies to determine the pH influence, contact time, and adsorbent particles concentration on the adsorption of arsenic were carried out along with fl...

  11. A novel fiber-based adsorbent technology

    Reynolds, T.A. [Chemica Technologies, Inc., Bend, OR (United States)

    1997-10-01

    In this Phase I Small Business Innovation Research program, Chemica Technologies, Inc. is developing an economical, robust, fiber-based adsorbent technology for removal of heavy metals from contaminated water. The key innovation is the development of regenerable adsorbent fibers and adsorbent fiber cloths that have high capacity and selectivity for heavy metals and are chemically robust. The process has the potential for widespread use at DOE facilities, mining operations, and the chemical process industry.

  12. Laser-induced production of large carbon-based toroids

    We report on the production of large carbon-based toroids (CBTs) from fullerenes. The process involves two-step laser irradiation of a mixed fullerene target (76% C60, 22% C70). Transmission electron microscopy (TEM) clearly identifies toroidal-shaped structures as well as Q-shaped constructs. The typical diameters of the CBTs are ∼0.2-0.3 μm with tubular diameters of ∼50-100 nm, but toroids as wide as 0.5 μm are observed making them nanostructures on the verge of being microstructures

  13. Results of testing various natural gas desulfurization adsorbents

    Israelson, Gordon

    2004-06-01

    This article presents the results of testing many commercially available and some experimental sulfur adsorbents. The desired result of our testing was to find an effective method to reduce the quantity of sulfur in natural gas to less than 100 ppb volume (0.1 ppm volume). An amount of 100 ppb sulfur is the maximum limit permitted for Siemens Westinghouse solid oxide fuel cells (SOFCs). The tested adsorbents include some that rely only on physical adsorption such as activated carbon, some that rely on chemisorption such as heated zinc oxide, and some that may use both processes. The testing was performed on an engineering scale with beds larger than those used for typical laboratory tests. All tests were done at about 3.45 barg (50 psig). The natural gas used for testing was from the local pipeline in Pittsburgh and averaged 6 ppm volume total sulfur. The primary sulfur species were dimethyl sulfide (DMS), isopropyl mercaptan, tertiary butyl mercaptan, and tetrahydrothiophene. Some tests required several months to achieve a sulfur breakthrough of the bed. It was found that DMS always came through a desulfurizer bed first, independent of adsorption process. Since the breakthrough of DMS always exceeds the 100 ppb SOFC sulfur limit before other sulfurs were detected, an index was created to rate the adsorbents in units of ppm DMS × absorbent bed volume. This index is useful for calculating the expected adsorbent bed lifetime before sulfur breakthrough when the inlet natural gas DMS content is known. The adsorbents that are included in these reports were obtained from suppliers in the United States, the Netherlands, Japan, and England. Three activated carbons from different suppliers were found to have identical performance in removing DMS. One of these activated carbons was operated at four different space velocities and again showed the same performance. When using activated carbon as the basis of comparison for other adsorbents, three high-performance adsorbents

  14. Biological and ecological responses to carbon-based nanomaterials

    Ratnikova, Tatsiana A.

    This dissertation examines the biological and ecological responses to carbon nanoparticles, a major class of nanomaterials which have been mass produced and extensively studied for their rich physical properties and commercial values. Chapter I of this dissertation offers a comprehensive review on the structures, properties, applications, and implications of carbon nanomaterials, especially related to the perspectives of biological and ecosystems. Given that there are many types of carbon nanomaterials available, this chapter is focused on three major types of carbon-based nanomaterials only, namely, fullerenes, single walled and multi-walled carbon nanotubes. On the whole organism level, specifically, Chapter II presents a first study on the fate of fullerenes and multiwalled carbon nanotubes in rice plants, which was facilitated by the self assembly of these nanomaterials with NOM. The aspects of fullerene uptake, translocation, biodistribution, and generational transfer in the plants were examined and quantified using bright field and electron microscopy, FT-Raman, and FTIR spectroscopy. The uptake and transport of fullerene in the plant vascular system were attributed to water transpiration, convection, capillary force, and the fullerene concentration gradient from the roots to the leaves of the plants. On the cellular level, Chapter III documents the differential uptake of hydrophilic C60(OH)20 vs. amphiphilic C70-NOM complex in Allium cepa plant cells and HT-29 colon carcinoma cells. This study was conducted using a plant cell viability assay, and complemented by bright field, fluorescence and electron microscopy imaging. In particular, C60(OH)20 and C70-NOM showed contrasting uptake in both the plant and mammalian cells, due to their significant differences in physicochemistry and the presence of an extra hydrophobic plant cell wall in the plant cells. Consequently, C60(OH)20 was found to induce toxicity in Allium cepa cells but not in HT-29 cells, while C70

  15. Natural material adsorbed onto a polymer to enhance immune function

    Reinaque AP

    2012-08-01

    Full Text Available Ana Paula Barcelos Reinaque,1 Eduardo Luzía França,2 Edson Fredulin Scherer,3 Mayra Aparecida Côrtes,1 Francisco José Dutra Souto,4 Adenilda Cristina Honorio-França51Post Graduate Program in Material Science, 2Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, 3Post Graduate Program in Material Science, Institute of Biological and Health Science, Federal University of Mato Grosso, Pontal do Araguaia, 4Faculty of Medical Sciences, Federal University of Mato Grosso, Cuiabá, 5Institute of Biological and Health Science, Federal University of Mato Grosso, Pontal do Araguaia, MT, BrazilBackground: In this study, we produced poly(ethylene glycol (PEG microspheres of different sizes and adsorbing a medicinal plant mixture, and verified their effect in vitro on the viability, superoxide production, and bactericidal activity of phagocytes in the blood.Methods: The medicinal plant mixture was adsorbed onto PEG microspheres and its effects were evaluated by flow cytometry and fluorescence microscopy.Results: Adsorption of the herbal mixture onto the PEG microspheres was achieved and the particles were internalized by phagocytes. PEG microspheres bearing the adsorbed herbal mixture stimulated superoxide release, and activated scavenging and microbicidal activity in phagocytes. No differences in functional activity were observed when the phagocytes were not incubated with PEG microspheres bearing the adsorbed herbal mixture.Conclusion: This system may be useful for the delivery of a variety of medicinal plants and can confer additional protection against infection. The data reported here suggest that a polymer adsorbed with a natural product is a treatment alternative for enhancing immune function.Keywords: natural product, polymer, adsorption, immune function, phagocytes

  16. Scanning tunneling microscopy theory for an adsorbate: Application to adenine adsorbed on a graphite surface

    Ou-Yang, Hui; Marcus, R. A.; Källebring, Bruno

    1994-01-01

    An expression is obtained for the current in scanning tunneling microscopy (STM) for a single adsorbate molecule. For this purpose the ``Newns–Anderson'' treatment (a ``discrete state in a continuum'' treatment) is used to obtain wave functions and other properties of the adsorbate/substrate system. The current is expressed in terms of the adsorbate–tip matrix elements, and an effective local density of states of the adsorbate/substrate system, at the adsorbate. As an example, the treatment i...

  17. 扩张床吸附剂:制备及功能化%Adsorbents for Expanded Bed Adsorption: Preparation and Functionalization

    赵珺; 姚善泾; 林东强

    2009-01-01

    Expanded bed adsorption (EBA), a promising and practical separation technique, has been widely stud-ied in the past two decades. The development of adsorbents for EBA process is a challenging course, with the spe-cial design and preparation according to the target molecules and specific expanded bed systems. Many types of supporting matrices for expanded bed adsorbents have been developed, and their preparation methods are being consummated gradually. These matrices are activated and then coupled with ligands to form functionalized adsorb-ents, including ion-exchange adsorbents, affinity adsorbents, mixed mode adsorbents, hydrophobic charge induction chromatography adsorbents and others. In this review, the preparation of the matrices for EBA process is summa-rized, and the coupling of ligands to the matrices to prepare functionalized adsorbents is discussed as well.

  18. Complete braided adsorbent for marine testing to demonstrate 3g-U/kg-adsorbent

    Janke, Chris [ORNL; Yatsandra, Oyola [ORNL; Mayes, Richard [ORNL; none,; Gill, Gary [PNNL; Li-Jung, Kuo [PNNL; Wood, Jordana [PNNL; Sadananda, Das [ORNL

    2014-04-30

    ORNL has manufactured four braided adsorbents that successfully demonstrated uranium adsorption capacities ranging from 3.0-3.6 g-U/kg-adsorbent in marine testing at PNNL. Four new braided and leno woven fabric adsorbents have also been prepared by ORNL and are currently undergoing marine testing at PNNL.

  19. A theoretical study of adsorbate-adsorbate interactions on Ru(0001)

    Mortensen, Jens Jørgen; Hammer, Bjørk; Nørskov, Jens Kehlet

    1998-01-01

    Using density functional theory we study the effect of pre-adsorbed atoms on the dissociation of N(2) and the adsorption of N, N(2), and CO on Ru(0001). We have done calculations for pre-adsorbed Na, Cs, and S, and find that alkali atoms adsorbed close to a dissociating N(2) molecule will lower t...

  20. CONDUCTIVITY METHOD APPLIED TO THE STUDY OF INTERACTION BETWEEN ADSORBENT AND ADSORBATE I.ADSORPTION OF LOW CONCENYRATION OF FREE ACID BY REGENERABLE CHITIN

    ChenBingren; HeGuangping; 等

    1997-01-01

    The adsorption of low concentration of free acid by regenerable chitin is followed by electric conductance determination.The effect of acid concentratioin,content of functioinal amino groups,and ionic strength on adsorption was discussed.Experimental results indicate that the active centre of regenerable chitin is the free amino groups on ist surface ,and that the rate of adsorption of free acid was found to be affected by two factors:the interaction between the adsorbent and the adsorbate in solution and that between the adsorbate molecules or ions in solution.

  1. A study on the carbon-based sorbents injection for gas phase mercury removal from flue gas

    Lee, S.; Rhim, Y.; Kim, S.; Park, Y. (and others) [Korea Institute of Energy Research, Daejoen (Republic of Korea). Clean Energy Research Department

    2003-07-01

    To develop carbon-based sorbents to be used in gas-phase mercury removal, the performance of virgin activated carbons (AC) and that of chemically treated activated carbons were compared. Virgin activated carbons (ACs) were made of bituminous coal, lignite, anthracite and NSH4X10. Chemical treated ACs used were those impregnated with sulphuric acid, nitric acid, 1% sulfur, and with mixed sulphuric and nitric acid. Pre-oxidation of activated carbons with acids was also investigated and adsorption performances were compared. Injection of activated carbons has been investigated and the influential factors such as temperature, carbon dose were also discussed. 5 refs., 4 figs., 2 tabs.

  2. Fluorescence dynamics of microsphere-adsorbed sunscreens

    Krishnan, R.

    2005-03-01

    Sunscreens are generally oily substances which are prepared in organic solvents, emulsions or dispersions with micro- or nanoparticles. These molecules adsorb to and integrate into skin cells. In order to understand the photophysical properties of the sunscreen, we compare steady-state and time-resolved fluorescence in organic solvent of varying dielectric constant ɛ and adsorbed to polystyrene microspheres and dispersed in water. Steady-state fluorescence is highest and average fluorescence lifetime longest in toluene, the solvent of lowest ɛ. However, there is no uniform dependence on ɛ. Sunscreens PABA and padimate-O show complex emission spectra. Microsphere-adsorbed sunscreens exhibit highly non-exponential decay, illustrative of multiple environments of the adsorbed molecule. The heterogeneous fluorescence dynamics likely characterizes sunscreen adsorbed to cells.

  3. Nanovalved Adsorbents for CH4 Storage.

    Song, Zhuonan; Nambo, Apolo; Tate, Kirby L; Bao, Ainan; Zhu, Minqi; Jasinski, Jacek B; Zhou, Shaojun J; Meyer, Howard S; Carreon, Moises A; Li, Shiguang; Yu, Miao

    2016-05-11

    A novel concept of utilizing nanoporous coatings as effective nanovalves on microporous adsorbents was developed for high capacity natural gas storage at low storage pressure. The work reported here for the first time presents the concept of nanovalved adsorbents capable of sealing high pressure CH4 inside the adsorbents and storing it at low pressure. Traditional natural gas storage tanks are thick and heavy, which makes them expensive to manufacture and highly energy-consuming to carry around. Our design uses unique adsorbent pellets with nanoscale pores surrounded by a coating that functions as a valve to help manage the pressure of the gas and facilitate more efficient storage and transportation. We expect this new concept will result in a lighter, more affordable product with increased storage capacity. The nanovalved adsorbent concept demonstrated here can be potentially extended for the storage of other important gas molecules targeted for diverse relevant functional applications. PMID:27124722

  4. NOx adsorber and method of regenerating same

    Endicott, Dennis L.; Verkiel, Maarten; Driscoll, James J.

    2007-01-30

    New technologies, such as NOx adsorber catalytic converters, are being used to meet increasingly stringent regulations on undesirable emissions, including NOx emissions. NOx adsorbers must be periodically regenerated, which requires an increased fuel consumption. The present disclosure includes a method of regenerating a NOx adsorber within a NOx adsorber catalytic converter. At least one sensor positioned downstream from the NOx adsorber senses, in the downstream exhaust, at least one of NOx, nitrous oxide and ammonia concentrations a plurality of times during a regeneration phase. The sensor is in communication with an electronic control module that includes a regeneration monitoring algorithm operable to end the regeneration phase when a time rate of change of the at least one of NOx, nitrous oxide and ammonia concentrations is after an expected plateau region begins.

  5. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent

    Awual, Md. Rabiul, E-mail: awual.rabiul@jaea.go.jp [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Yaita, Tsuyoshi [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Taguchi, Tomitsugu [Nano-Structure Synthesis Research Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan)

    2014-08-15

    Graphical abstract: - Highlights: • DB24C8 crown ether was functionalized for preparation of conjugate adsorbent. • Radioactive {sup 137}Cs can be selectively removed by the conjugate adsorbent. • Adsorbent can effectively capture Cs even in the presence of a high amount Na and K. • Adsorbent is reversible and able to be reused without significant deterioration. - Abstract: Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs–π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations.

  6. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent

    Graphical abstract: - Highlights: • DB24C8 crown ether was functionalized for preparation of conjugate adsorbent. • Radioactive 137Cs can be selectively removed by the conjugate adsorbent. • Adsorbent can effectively capture Cs even in the presence of a high amount Na and K. • Adsorbent is reversible and able to be reused without significant deterioration. - Abstract: Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs–π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations

  7. High efficient acetalization of carbonyl compounds with diols catalyzed by novel carbon-based solid strong acid catalyst

    2007-01-01

    The novel carbon-based acid catalyst has been applied to catalyzing the acetalization and ketalization. The results showed that the catalyst was very efficient with the average yield over 93%. The novel heterogeneous catalyst has the advantages of high activity, wide applicability even to 7-membered ring acetals, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the green process greatly.

  8. The structure of deuterated benzene films adsorbed on the graphite (0001) basal plane: what happens below and above the monolayer coverage?

    Bahn, Emanuel; Hedgeland, Holly; Jardine, Andrew P.; Henry, Paul F.; Hansen, Thomas C.; Fouquet, Peter

    2014-01-01

    An exact description of the interactions in aromatic carbon systems is a key condition for the design of carbon based nanomaterials. In this paper we investigate the binding and adsorbate structure of the simplest prototype system in this class – the single aromatic ring molecule benzene on graphite. We have collected neutron diffraction data of the ordered phase of deuterated benzene, C6D6, adsorbed on the graphite (0001) basal plane surface. We examined relative coverages from 0.15 up to 1....

  9. Polydopamine meets porous membrane: A versatile platform for facile preparation of membrane adsorbers.

    Fan, Jinxin; Luo, Jianquan; Chen, Xiangrong; Wan, Yinhua

    2016-05-27

    Polydopamine, as an intermediate layer coated on PES membrane, was applied to fabricate various membrane adsorbers. Anion-exchange, hydrophobic interaction and affinity membrane adsorbers prepared by this facile method exhibited a high selectivity in fractionation of IgG (immunoglobulin)/HSA (human serum albumin) mixture. The anion-exchange membrane adsorber containing polyethylenimine (PEI) improved the HSA purity from 17.7% to 96.7%; The hydrophobic interaction membrane adsorber with Dodecyl mercaptan (DDM) as ligand obtained an IgG purity of 94.6%; Histidine attached affinity membrane chromatography achieved nearly a 100% purity of IgG. The present work indicated that the polydopamine layer not only activated membrane surface to attach various adsorptive ligands under the mild condition, but also reduced non-specific adsorption. Due to the versatile conjunction function, this facile mussel-inspired coating is also promising for the preparation of diverse membrane adsorbers. PMID:27131962

  10. Electric field cancellation on quartz by Rb adsorbate-induced negative electron affinity

    Shaffer, James

    2016-05-01

    We investigate the (0001) surface of single crystal quartz with a submonolayer of Rb adsorbates. Using Rydberg atom electromagnetically induced transparency, we investigate the electric fields resulting from Rb adsorbed on the quartz surface, and measure the activation energy of the Rb adsorbates. We show that the adsorbed Rb induces a negative electron affinity (NEA) on the quartz surface. The NEA surface allows low energy electrons to bind to the surface and cancel the electric field from the Rb adsorbates. Our results are important for integrating Rydberg atoms into hybrid quantum systems and the fundamental study of atom-surface interactions, as well as applications for electrons bound to a 2D surface. This work was supported by the DARPA Quasar program by a Grant through ARO (60181-PH-DRP) and the AFOSR (FA9550-12-1-0282),.

  11. The dynamic adsorption of Xe on a fixed bed adsorber at 77 K

    Long, Bin; Wang, Qun- Shu; Feng, Shu- Juan; Zhou, Guo- Qing; Feng, Tian- Cheng; Tian, Yan- Jie; Ma, Huai- Cheng

    2016-01-01

    During the design of fixed bed adsorbers, it is vital to understand the dynamic adsorption properties of the system. Because temperature is one of the most important factors affecting adsorbent performance, such that the dynamic adsorption coefficients tend to increase as the temperature decreases, the dynamic adsorption characteristics of Xe on a fixed bed adsorber at 77 K were studied in the present work to minimize the volume of fixed bed adsorber, employing a variety of adsorbents under different operational conditions. The results show that the adsorption performance of carbon molecular sieve is superior to that of activated carbon. And both operational conditions and the presence of gaseous impurities were found to affect adsorption properties.

  12. Limiting factors for carbon based chemical double layer capacitors

    Rose, M. Frank; Johnson, C.; Owens, T.; Stevens, B.

    1993-01-01

    The Chemical Double Layer (CDL) capacitor improves energy storage density dramatically when compared with conventional electrolytic capacitors. When compared to batteries, the CDL Capacitor is much less energy dense; however, the power density is orders of magnitude better. As a result, CDL-battery combinations present an interesting pulse power system with many potential applications. Due to the nature of the CDL it is inherently a low voltage device. The applications of the CDL can be tailored to auxiliary energy and burst mode storages which require fast charge/discharge cycles. Typical of the applications envisioned are power system backup, directed energy weapons concepts, electric automobiles, and electric actuators. In this paper, we will discuss some of the general characteristics of carbon-based CDL technology describing the structure, performance parameters, and methods of construction. Further, analytical and experimental results which define the state of the art are presented and described in terms of impact on applications.

  13. Carbon-Based Fibrous EDLC Capacitors and Supercapacitors

    C. Lekakou

    2011-01-01

    Full Text Available This paper investigates electrochemical double-layer capacitors (EDLCs including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF and a multiwall carbon nanotube (CNT electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance tests. The best separator was a glass fibre-fine pore filter. The carbon woven fabric electrode and the corresponding supercapacitor exhibited superior performance per unit area, whereas the multiwall carbon nanotube electrode and corresponding supercapacitor demonstrated excellent specific properties. The hybrid CWF-CNT electrodes did not show a combined improved performance due to the lack of carbon nanotube penetration into the carbon fibre fabric.

  14. Carbon-based strong solid acid for cornstarch hydrolysis

    Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

    2015-10-01

    Highly sulfonated carbonaceous spheres with diameter of 100-500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

  15. CVD synthesis of carbon-based metallic photonic crystals

    Zakhidov, A A; Baughman, R H; Iqbal, Z

    1999-01-01

    Three-dimensionally periodic nanostructures on the scale of hundreds of nanometers, known as photonic crystals, are attracting increasing interest because of a number of exciting predicted properties. In particular, interesting behavior should be obtainable for carbon- based structures having a dimensional scale larger than fullerenes and nanotubes, but smaller than graphitic microfibers. We show here how templating of porous opals by chemical vapor deposition (CVD) allows us to obtain novel types of graphitic nanostructures. We describe the synthesis of new cubic forms of carbon having extended covalent connectivity in three dimensions, which provide high electrical conductivity and unit cell dimensions comparable to optical wavelengths. Such materials are metallic photonic crystals that show intense Bragg diffraction. (14 refs).

  16. Reconstruction of adsorption potential in Polanyi-based models and application to various adsorbents.

    Pan, Bingjun; Zhang, Huichun

    2014-06-17

    The equilibrium Polanyi adsorption potential was reconstructed as ε = -RT ln(Ca(or H)/δ) to correlate the characteristic energy (E) of Polanyi-based models (qe = f[ε/E]) with the properties or structures of absorbates, where qe is the equilibriumn adsorption capacity, Ca(or H) is the converted concentration from the equilibrium aqueous concentration at the same activity and corresponds to the adsorption from the gas or n-hexadecane (HD) phase by the water-wet adsorbent, and "δ" is an arbitrary divisor to converge the model fitting. Subsequently, the modified Dubinin-Astakhov model based on the reconstructed ε was applied to aqueous adsorption on activated carbon, black carbon, multiwalled carbon nanotubes, and polymeric resin. The fitting results yielded intrinsic characteristic energies Ea, derived from aqueous-to-gas phase conversion, or EH, derived from aqueous-to-HD phase conversion, which reflect the contributions of the overall or specific adsorbate-adsorbent interactions to the adsorption. Effects of the adsorbate and adsorbent properties on Ea or EH then emerge that are unrevealed by the original characteristic energy (Eo), i.e., adsorbates with tendency to form stronger interactions with an adsorbent have larger Ea and EH. Additionally, comparison of Ea and EH allows quantitative analysis of the contributions of nonspecific interactions, that is, a significant relationship was established between the nonspecific interactions and Abraham's descriptors for the adsorption of all 32 solutes on the four different adsorbents: (Ea - EH) = 24.7 × V + 9.7 × S - 19.3 (R(2) = 0.97), where V is McGowan's characteristic volume for adsorbates, and S reflects the adsorbate's polarity/polarizability. PMID:24815932

  17. States of water adsorbed on perindopril crystals

    Stepanov, V. A.; Khmelevskaya, V. S.; Bogdanov, N. Yu.; Gorchakov, K. A.

    2011-10-01

    The relationship between the structural state of adsorbed water, the crystal structure of the substances, and the solubility of the perindopril salt C19H32N2O5 · C4H11N in water was studied by IR spectroscopy and X-ray diffractometry. The high-frequency shift of the stretching vibrations of adsorbed water and the solubility depend on the crystal structure of the drug substance. A reversible chemical reaction occurred between the adsorbed water and the perindopril salt.

  18. Characterization of adsorbed dicarbonyls of rhodium

    We have studies the adsorbed states of CO on dispersed RH in Y zeolites by solid-state 13C NMR spectroscopy. The structure of the dicarbonyl form of adsorbed rhodium has been revealed using a Carr-Purcell-Meiboom-Gill multiple pulse sequence. NMR lineshape calculations show that adsorbed Rh(CO)2 species are undergoing a 180 deg. flipping motion about the C2 axis which bisects the C-Rh-C angle. Spectra calculated with this motional model have been compared with published spectra of CO on Rh-Y zeolites. (author). 7 refs.; 3 figs

  19. Effect of adsorbent addition on floc formation and clarification.

    Younker, Jessica M; Walsh, Margaret E

    2016-07-01

    Adding adsorbent into the coagulation process is an emerging treatment solution for targeting hard-to-remove dissolved organic compounds from both drinking water and industrial wastewater. The impact of adding powdered activated carbon (PAC) or organoclay (OC) adsorbents with ferric chloride (FeCl3) coagulant was investigated in terms of potential changes to the coagulated flocs formed with respect to size, structure, and breakage and regrowth properties. The ability of dissolved air flotation (DAF) and sedimentation (SED) clarification processes to remove hybrid adsorbent-coagulant flocs was also evaluated through clarified water quality analysis of samples collected in bench-scale jar test experiments. The jar tests were conducted using both a synthetic fresh water and oily wastewater test water spiked with dissolved aromatic compounds phenol and naphthalene. Results of the study demonstrated that addition of adsorbent reduced the median coagulated floc size by up to 50% but did not affect floc strength or regrowth potential after application of high shear. Experimental results in fresh water demonstrated that sedimentation was more effective than DAF for clarification of both FeCl3-PAC and FeCl3-OC floc aggregates. However, experimental tests performed on the synthetic oily wastewater showed that coagulant-adsorbent floc aggregates were effectively removed with both DAF and sedimentation treatment, with lower residual turbidity achieved in clarified water samples than with coagulation treatment alone. Addition of OC or PAC into the coagulation process resulted in removals of over half, or nearly all of the dissolved aromatics, respectively. PMID:27064206

  20. Solid Adsorbents for Low Temperature CO2 Capture with Low Energy Penalties Leading to More Effective Integrated Solutions for Power Generation and Industrial Processes

    Nannan eSun

    2015-03-01

    Full Text Available CO2 capture represents the key technology for CO2 reduction within the framework of CO2 capture, utilization, and storage (CCUS. In fact, the implementation of CO2 capture extends far beyond CCUS since it will link the CO2 emission and recycling sectors, and when renewables are used to provide necessary energy input, CO2 capture would enable a profitable zero- or even negative-emitting and integrated energy-chemical solution. To this end, highly efficient CO2 capture technologies are needed, and adsorption using solid adsorbents has the potential to be one of the ideal options. Currently, the greatest challenge in this area is the development of adsorbents with high performance that balances a range of optimization-needed factors, those including costs, efficiency, and engineering feasibility. In this review, recent advances on the development of carbon-based and immobilized organic amines-based CO2 adsorbents are summarized, the selection of these particular categories of materials is because they are among the most developed low temperature (<100 oC CO2 adsorbents up to date, which showed important potential for practical deployment at pilot-scale in the near future. Preparation protocols, adsorption behaviors as well as pros and cons of each type of the adsorbents are presented, it was concluded that encouraging results have been achieved already, however, the development of more effective adsorbents for CO2 capture remains challenging and further innovations in the design and synthesis of adsorbents are needed.

  1. Adsorption capacity of various adsorbents for decolorization of wastewater

    Romčević, Gorana

    2014-01-01

    Adsorption is applied for the removal of dyes from wastewater effluent from textile and other industries. Dyes from wastewater need to be removed before it mixes with water bodies. Among the treatment options, adsorption appears to have considerable potential for the removal of colour from wastewaters. Activated carbon is the most widely used adsorbent, but its use is limited due to its high cost. This cost problem has led to a search for the use of alternate cheap and efficient materials. ...

  2. Silver diffusion over silicon surfaces with adsorbed tin atoms

    Silver diffusion over the (111), (100), and (110) surfaces of silicon with preliminarily adsorbed tin atoms is studied by Auger electron spectroscopy and low-energy electron diffraction. Diffusion is observed only on the surface of Si(111)-2√3 × 2√3-Sn. The diffusion mechanism is established. It is found that the diffusion coefficient depends on the concentration of diffusing atoms. The diffusion coefficient decreases with increasing silver concentration, while the activation energy and the preexponential factor increase

  3. Importance of Micropore-Mesopore Interfaces in Carbon Dioxide Capture by Carbon-Based Materials.

    Durá, Gema; Budarin, Vitaliy L; Castro-Osma, José A; Shuttleworth, Peter S; Quek, Sophie C Z; Clark, James H; North, Michael

    2016-08-01

    Mesoporous carbonaceous materials (Starbons®) derived from low-value/waste bio-resources separate CO2 from CO2 /N2 mixtures. Compared to Norit activated charcoal (AC), Starbons® have much lower microporosities (8-32 % versus 73 %) yet adsorb up to 65 % more CO2 . The presence of interconnected micropores and mesopores is responsible for the enhanced CO2 adsorption. The Starbons® also showed three-four times higher selectivity for CO2 adsorption rather than N2 adsorption compared to AC. PMID:27336368

  4. New liquid waste control with tannin adsorbent

    Since 1971, the Mitsubishi Nuclear Fuel Co., Ltd. (MNF) has been fabricating PWR fuels and developing related technology and processes. In the UF6 reconversion lines of MNF, the ammonium diuranate (ADU) process has been operating and the newly developed process of liquid waste treatment was installed last year. The characteristic of this process is to use insoluble tannin adsorbent which has been developed by MNF. The tannin adsorbent is not only an effective means to adsorb heavy metals such as uranium and plutonium but is also easy to incinerate at low temperature. Control of radioactive liquid waste from nuclear facilities is generally implemented by co-precipitation. However, it produces secondary wastes such as noncombustible materials which include radionuclides and it is anticipated that the storage and disposal of those wastes will be at high cost. Those are the reasons why tannin adsorbent has an advantage, and why MNF develops it. (author)

  5. Dissolved Air Flotation of arsenic adsorbent particles

    M. Santander

    2015-04-01

    Full Text Available The removal of arsenic from synthetic effluent was studied using the adsorbent particle flotation technique (APF and dissolved air flotation (DAF. A sample of an iron mineral was used as adsorbent particles of arsenic, ferric chloride as coagulant, cationic polyacrylamide (NALCO 9808 as flocculants, and sodium oleate as collector. Adsorption studies to determine the pH influence, contact time, and adsorbent particles concentration on the adsorption of arsenic were carried out along with flotation studies to determine the removal efficiency of adsorbents particles. The results achieved indicate that the adsorption kinetic of arsenic is very rapid and that in range of pH’s from 2 to 7 the adsorption percentages remain constant. The equilibrium conditions were achieved in 60 minutes and about 95% of arsenic was adsorbed when used an adsorbent concentration of 2 g/L and pH 6.3. The maximum adsorption capacity of adsorbent particles was 4.96 mg/g. The mean free energy of adsorption (E was found to be 2.63 kJ/mol, which suggests physisorption. The results of the flotation studies demonstrated that when synthetic effluents with 8.9 mg/L of arsenic were treated under the following experimental conditions; 2 g/L of adsorbent particles, 120 mg/L of Fe(III, 2 mg/L of Nalco 9808, 20 mg/L of sodium oleate, and 40% of recycle ratio in the DAF, it was possible to reach 98% of arsenic removal and 6.3 NTU of residual turbidity in clarified synthetic effluent.

  6. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    Sharma, Pramod K.; Hickey, Gregory S.

    1994-01-01

    Composite molecular-sieve material has pore structure designed specifically for preferential adsorption of organic molecules for sizes ranging from 3 to 6 angstrom. Design based on principle that contaminant molecules become strongly bound to surface of adsorbent when size of contaminant molecules is nearly same as that of pores in adsorbent. Material used to remove small organic contaminant molecules from vacuum systems or from enclosed gaseous environments like closed-loop life-support systems.

  7. ADSORBENTS USED IN THE CLEARANCE OF ENDOTOXIN

    YU Mei; LIU Tao; Hou Guanghui; YUAN Zhi

    2003-01-01

    A series of modified poly (methyl methacrylate, PMMA) resins were prepared and compared their adsorption abilities to endotoxin. The results showed that adsorbents, which were grafted with tertiary amine and long spacing arms, had the best adsorption capacities and good blood compatibility, It is hopeful to be used as adsorbent in hemoperfusion for clinical clearance of endotoxin. The influence of original concentration of endotoxin on adsorption and the adsorption mechanism were also investigated.

  8. Behavior of macromolecules in adsorbed layers

    2000-01-01

    A model for describing the behavior of macromolecules in adsorbed layers is developed by introducing a concept of distribution density of layer thickness U based on stochastic process and probabilistic statistics. The molecular behavior of layers adsorbed on clay particle surfaces is discussed; the random distribution and its statistics of the layer thickness are given by incorporating experimental results with an ionic polyelectrolyte with the molecular weight of 1.08×106 and chain charged density of 0.254.

  9. Membrane Perturbation Induced by Interfacially Adsorbed Peptides

    Zemel, Assaf; Ben-Shaul, Avinoam; May, Sylvio

    2004-01-01

    The structural and energetic characteristics of the interaction between interfacially adsorbed (partially inserted) α-helical, amphipathic peptides and the lipid bilayer substrate are studied using a molecular level theory of lipid chain packing in membranes. The peptides are modeled as “amphipathic cylinders” characterized by a well-defined polar angle. Assuming two-dimensional nematic order of the adsorbed peptides, the membrane perturbation free energy is evaluated using a cell-like model;...

  10. Removal of hydrogen sulfide at ambient conditions on cadmium/GO-based composite adsorbents.

    Florent, Marc; Wallace, Rajiv; Bandosz, Teresa J

    2015-06-15

    Cadmium-based materials with various hydroxide to carbonate ratios and their composites with graphite oxide were synthesized by a fast and simple precipitation procedure and then used as H2S adsorbents at ambient conditions in the dark or upon a visible light exposure. The structural properties and chemical features of the adsorbents were analyzed before and after hydrogen sulfide adsorption. The results showed that the high ratio of hydroxide to carbonate led to an improved H2S adsorption capacity. In moist conditions cadmium hydroxide was the best adsorbent. Moreover, it showed photoactive properties. While the incorporation of a graphene-based phase slightly decreased the extent of the improvement in the H2S adsorption capacity in moist conditions caused by photoactivity, its presence in the composites enhanced the performance in dry conditions. This was linked to photoactivity of CdS that can split H2S resulting in the formation of water in the system. The graphene-based phase enhanced the electron transfer and delayed the recombination of photoinduced charges. Carbonate-based materials showed a very good adsorption capacity in dark conditions in the presence of moisture. Upon the light exposure, CdS likely photocatalyzes the reduction of carbonate ions to formates/formaldehydes. Their deposition on the surface limits the number of sites available to H2S adsorption. PMID:25792480

  11. Photochemistry of Nitrate Adsorbed on Mineral Dust

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  12. Surface characterization of Ag/Titania adsorbents

    Samokhvalov, Alexander; Nair, Sachin; Duin, Evert C.; Tatarchuk, Bruce J.

    2010-03-01

    The Ag/Titania adsorbent for selective removal of the desulfurization-refractive polycyclic aromatic sulfur heterocycles (PASHs) from liquid hydrocarbon fuels was prepared, its total and the Ag specific surface area were determined and the surface reaction sites in the sorbent that may be active in the adsorptive selective desulfurization were characterized by several spectroscopic and surface science techniques. The sorbent contains Ag, Ti, O and spurious C on its surface, as by the XPS measurements. Silver is present as an oxide, as judged by the XPS Auger parameter (AP). The complementary electron spin resonance (ESR) spectroscopy confirms that the majority of Ag is present in the diamagnetic Ag 1+ form, with the minor concentration (˜0.1% of total Ag) present as Ag 2+. The findings by XPS and ESR are confirmed by the XRD, UV-vis spectroscopy and thermodynamic considerations. The supported Ag is highly dispersed on the surface of the titania support, with the particle size of ˜30-60 Å depending on Ag content, with an Ag specific surface area of ˜7-14 m 2/g, vs. the total surface area of ˜114-58 m 2/g.

  13. Carbon-based strong solid acid for cornstarch hydrolysis

    Nata, Iryanti Fatyasari, E-mail: yanti_tkunlam@yahoo.com [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Irawan, Chairul; Mardina, Primata [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Lee, Cheng-Kang, E-mail: cklee@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Rd. Sec.4, Taipei 106, Taiwan (China)

    2015-10-15

    Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO{sub 3}H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO{sub 3}H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use.

  14. Carbon-Based Nano-Electro-Mechanical-Systems

    Kaul, A. B.; Khan, A. R.; Megerian, K. G.; Epp, L.; LeDuc, G.; Bagge, L.; Jennings, A. T.; Jang, D.; Greer, J. R.

    2011-01-01

    We provide an overview of our work where carbon-based nanostructures have been applied to two-dimensional (2D) planar and three-dimensional (3D) vertically-oriented nano-electro-mechanical (NEM) switches. In the first configuration, laterally oriented single-walled nanotubes (SWNTs) synthesized using thermal chemical vapor deposition (CVD) were implemented for forming bridge-type 2D NEMS switches, where switching voltages were on the order of a few volts. In the second configuration, vertically oriented carbon nanofibers (CNFs) synthesized using plasma-enhanced (PE) CVD have been explored for their potential application in 3D NEMS. We have performed nanomechanical measurements on such vertically oriented tubes using nanoindentation to determine the mechanical properties of the CNFs. Electrostatic switching was demonstrated in the CNFs synthesized on refractory metallic nitride substrates, where a nanoprobe was used as the actuating electrode inside a scanning-electron-microscope. The switching voltages were determined to be in the tens of volts range and van der Waals interactions at these length scales appeared significant, suggesting such structures are promising for nonvolatile memory applications. A finite element model was also developed to determine a theoretical pull-in voltage which was compared to experimental results.

  15. Fachtagung 'carbon-nanophysics': carbon based organic optoelectronic devices

    Full text: Recent developments on carbon based organic light emitting diodes (OLEDs), photovoltaic diodes (OPVs) and photoactive organic field effect transistors (photOFETs) are discussed. The photophysics of such devices is based on the photoinduced charge and/or energy transfer interactions between donor type semiconducting conjugated materials and acceptor type conjugated molecules such as Buckminster-fullerene, C60. Furthermore, organic/inorganic nanoparticle based 'hybrid' devices will be discussed. This talk gives an overview of materials' aspect, charge-transport, and device physics of organic diodes and field-effect transistors. Due to the compatibility of carbon/ hydrogen based organic semiconductors with organic biomolecules and living cells there can be a great opportunity to integrate such organic semiconductor devices (biOFETs) with the living organisms. In general, bio/life sciences and information technology can be bridged in an advanced cybernetic approach using organic semiconductor devices embedded in bio-life sciences. This field of bio-organic electronic devices is proposed to be an important mission of organic semiconductor devices. (author)

  16. Determination of Cr and Cd concentration adsorbed by chicken feathers

    In this work the results of the samples analysis of chicken feathers are presented, used as adsorber of the heavy metals Cd and Cr present in water solutions with well-known concentrations of these metals. It was used the Neutron Activation Analysis technique (AAN), using the TRIGA Mark-III reactor of the Nuclear Center of Mexico. The obtained results they show the advantages of having a versatile installation for the analysis of this type of samples. By means of the analysis of the results, it was determined the feasibility of using chicken feathers like adsorber of these metals present in polluted waters, additionally, it was detected the presence of others polluting elements in the inputs to prepare the reference solutions as well as in the processes, so much of preparation of the feathers like of the metals adsorption. (Author)

  17. Radiolysis of alanine adsorbed in a clay mineral

    Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically γ-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine

  18. Adsorption and Desorption of Carbon Dioxide and Water Mixtures on Synthetic Hydrophobic Carbonaceous Adsorbents

    Finn, John E.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    Several synthetic carbonaceous adsorbents produced through pyrolysis of polymeric materials are available commercially. Some appear to have advantages over activated carbon for certain adsorption applications. In particular, they can have tailored hydrophobicities that are significantly greater than that of activated carbon, while moderately high surfaces areas are retained. These sorbents are being investigated for possible use in removing trace contaminants and excess carbon dioxide from air in closed habitats, plant growth chambers, and other applications involving purification of humid gas streams. We have analyzed the characteristics of a few of these adsorbents through adsorption and desorption experiments and standard characterization techniques. This paper presents pure and multicomponent adsorption data collected for carbon dioxide and water on two synthetic carbonaceous adsorbents having different hydrophobicities and capillary condensation characteristics. The observations are interpreted through consideration of the pore structure and surface chemistry of the solids and interactions between adsorbed carbon dioxide, water, and the solvent gas.

  19. Novel Fiber-Based Adsorbent Technology; FINAL

    The overall of this Department of Energy (DOE) Phase II SBIR program was to develop a new class of highly robust fiber-based adsorbents for recovery of heavy metals from aqueous waste-streams. The fiber-based adsorbents,when commercialized,will be used for clean up metals in aqueous waste-streams emanating from DOE facilities,industry,mining,and groundwater-cleanup operations.The amount of toxic waste released by these streams is of great significance.The U.S.Environment Protection Agency (EPA) reports that in 1990 alone,4.8 billion pounds of toxic chemicals were released into the environment.Of this waste,the metals-containing waste was the second largest contributor,representing 569 million pounds. This report presents the results of the Phase II program,which successfully synthesized noval fiber-based adsorbents for the removal of Group 12 metals(i.e.mercury),Group 14 metals (lead),and Group 10 metals(platinum and palladium) from contaminated groundwater and industrial waste streams.These fiber-based adsorbents are ideally suited for the recovery of metal ions from aqueous waste streams presently not treatable due to the degrading nature of corrosive chemicals or radioactive components in the feed stream. The adsorbents developed in this program rely on chemically resistant and robust carbon fibers and fabrics as supports for metal-ion selective ligands.These adsorbents demonstrate loading capacities and selectivities for metal ions exceeding those of conventional ion-exchange resins.The adsorbents were also used to construct filter modules that demonstrate minimal fouling,minimal compaction,chemical and physical robustness,and regeneration of metal loading capacity without loss of performance

  20. The Recovery of Used Palm Cooking Oil Using Bagasse as Adsorbent

    Rizki Wannahari

    2012-01-01

    Full Text Available Problem statement: The use and reduce cooking oil is a common phenomena in our society. While some of this cooking oil is further refine most of it however and not subject to any filtration in the refining process medium such as carbon active, silica are commonly use. Approach: The used of bagasse as adsorbent is not common. This is odd especially when structural component of bagasse which is made up of carbon material is suitable as adsorbent and the fact that, adsorbent bagasse further reduce solid waste disposal and hence reducing one source of environmental pollution. Results: This study was undertaken to explore the possibility of using bagasse as adsorbent. Specifically, bagasse is being experimented to reduce the harmful content such as Free Fatty Acid (FFA and color density in used cooking oil. The variation of adsorbent weight and contact time are used in this research as parameters to determine the effective time and the amount of adsorbent that should be used in the oil refining process. From the experiment conducted, it can be established that bagasse when use as an adsorbent can reduce FFA to 82.14% which is lower the harmful limit. Conclusion/Recommendations: This result is obtained when using 7.5 gr of bagasse for 60 m contact time. Similarly, the color of oil is reduced to 75.67% which is significant and this is base on 10 gr of bagasse with 60 m of contact time.

  1. Waste Material Adsorbents for Zinc Removal from Wastewater: A Comprehensive Review

    Haider M. Zwain

    2014-01-01

    Full Text Available This review examines a variety of adsorbents and discusses mechanisms, modification methods, recovery and regeneration, and commercial applications. A summary of available researches has been composed by a wide range of potentially low-cost modified adsorbents including activated carbon, natural source adsorbents (clay, bentonite, zeolite, etc., biosorbents (black gram husk, sugar-beet pectin gels, citrus peels, banana and orange peels, carrot residues, cassava waste, algae, algal, marine green macroalgae, etc., and byproduct adsorbents (sawdust, lignin, rice husk, rice husk ash, coal fly ash, etc.. From the literature survey, different adsorbents were compared in terms of Zn2+ adsorption capacity; also Zn2+ adsorption capacity was compared with other metals adsorption. Thus, some of the highest adsorption capacities reported for Zn2+ are 168 mg/g powdered waste sludge, 128.8 mg/g dried marine green macroalgae, 73.2 mg/g lignin, 55.82 mg/g cassava waste, and 52.91 mg/g bentonite. Furthermore, modification of adsorbents can improve adsorption capacity. Regeneration cost is important, but if consumption of virgin adsorbent is reduced, then multiple economic, industrial, and environmental benefits can be gained. Finally, the main drawback of the already published Zn2+ adsorption researches is that their use is still in the laboratory stage mostly without scale-up, pilot studies, or commercialization.

  2. Design improvements for a collector/generator/adsorber of a solid adsorption solar refrigerator

    Ogueke, N.V.; Anyanwu, E.E. [Mechanical Engineering Department, Federal University of Technology, P.M.B. 1526, Owerri (Nigeria)

    2008-11-15

    A study of the effects of different collector design parameters on the performances of a solar powered solid adsorption refrigerator is presented. The refrigerator uses activated carbon/methanol as the adsorbent/refrigerant pair. The study was undertaken using a computer simulation program developed from a transient analysis of the system. The parameters tested are the collector plate emissivity/absorptivity combination, adsorbent packing density, tube spacing, outer tube outside diameter, adsorbent thermal conductivity, heat transfer coefficient at adsorbent/tube interface, and adsorbent tube/collector plate materials combination. Two performance indicators namely, condensate yield and coefficient of performance (COP) were used in the study as figures of merit. A multiple regression technique was used to correlate the performance indicators with the collector parameters through a quadratic relation. Consequently an objective function, suitable for selecting optimal values of the parameters is defined, subject to specified constraints. Selecting the COP as the preferred indicator parameter, optimization was then carried out. Improvements in the ranges of 29-38% for COP and 26-35% for condensate yield were obtained with optimal choices of tube spacing, adsorbent packing density and collector plate/adsorbent tube material combinations. (author)

  3. PURIFICATION OF GINKGO LEAVES EXTRACT WITH MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMERS

    XUMingcheng; XUMancai; 等

    2000-01-01

    The relationship between the adsorption properties for the active components of ginkgo leaves and the structure of the adsorbents based on urea-formaldehyde condensed polymers was investigated.The results revealed that these adsorbents showed very high adsorpton selectivity for both flavonol glycosides and terpene lactones contained in ginkgo leaves.Thus,an adsorption separation procedure for purification of ginkgo leaves extracts was developed.

  4. VALORIZATION AND BIODECOLORIZATION OF DYE ADSORBED ON LIGNOCELLULOSICS USING WHITE ROT FUNGI

    Nesrin Ozmen,; Ozfer Yesilada

    2012-01-01

    Biosorption of dyes by lignocelluloses may be an effective method for removing dyes from textile effluents. However, the resulting dye-adsorbed lignocellulosic materials may constitute another pollution problem. An integrated method can solve this problem. Here, various lignocelluloses were tested for their Astrazon Black and Astrazon Blue dyes removal activities. The dye adsorbed after 30 min contact time was 90% (45 mg/L), 70% (35 mg/L), and 98% (49 mg/L) for wheat bran, pine cone, and cott...

  5. Developing low-cost carbon-based sorbents for Hg capture from flue gas

    Perry, R.; Lakatos, J.; Snape, C.E.; Sun, C. [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre

    2005-07-01

    To help reduce the cost of Hg capture from flue gas a number of low-cost carbons are being investigated, including activated tyre char and PFA carbon, in conjunction with some of the pre-treatments that have been found to be effective for commercial actived carbons. Experimental conditions for screening the sorbents have been selected to determine breakthrough capacities rapidly. The unactivated carbons have low breakthrough capacities under the test conditions employed (around 0.1 mg g{sup -1}) but these improve upon steam activation (around 0.25 mg g{sup -1}) but are still lower than those of non-impregnated commercial activated carbons (around 0.4-0.7 mg g{sup -1}), due to their lower surface areas. Comparable improvements to the commercial carbons have been achieved for impregnation treatments, including sulfur and bromine. However, certain gasification chars do have much higher breakthrough capacities than commercial carbons used for flue gas injection. Manganese oxide impregnation with low concentration is particularly effective for the activated and unactivated carbons giving breakthrough capacities comparable to the commercial carbons. Pointers for further increasing breakthrough and equilibrium capacities for carbon-based sorbents are discussed. 7 refs., 1 fig., 3 tabs.

  6. Size selective hydrophobic adsorbent for organic molecules

    Sharma, Pramod K. (Inventor); Hickey, Gregory S. (Inventor)

    1997-01-01

    The present invention relates to an adsorbent formed by the pyrolysis of a hydrophobic silica with a pore size greater than 5 .ANG., such as SILICALITE.TM., with a molecular sieving polymer precursor such as polyfurfuryl alcohol, polyacrylonitrile, polyvinylidene chloride, phenol-formaldehyde resin, polyvinylidene difluoride and mixtures thereof. Polyfurfuryl alcohol is the most preferred. The adsorbent produced by the pyrolysis has a silicon to carbon mole ratio of between about 10:1 and 1:3, and preferably about 2:1 to 1:2, most preferably 1:1. The pyrolysis is performed as a ramped temperature program between about 100.degree. and 800.degree. C., and preferably between about 100.degree. and 600.degree. C. The present invention also relates to a method for selectively adsorbing organic molecules having a molecular size (mean molecular diameter) of between about 3 and 6 .ANG. comprising contacting a vapor containing the small organic molecules to be adsorbed with the adsorbent composition of the present invention.

  7. Black Molecular Adsorber Coatings for Spaceflight Applications

    Abraham, Nithin Susan; Hasegawa, Mark Makoto; Straka, Sharon A.

    2014-01-01

    The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.

  8. Defluoridization Using a Natural Adsorbent, Strychnos Potatorum

    S.Rayappan

    2014-10-01

    Full Text Available The study assessed the suitability of low-cost natural adsorbent to effectively remediate fluoride contaminated water. The removal of fluoride from aqueous solution by using Strychnos Potatorum was studied in batch technique. Influence of pH, adsorbent dose, contact time, co ions, speed and initial concentration on the adsorption were investigated. The maximum removal of fluoride ion was obtained at pH 7. The removal of fluoride was expressed with Langmuir and Freundlich isotherm. It was found that the sufficient time for adsorption equilibrium of fluoride ion was 1 hour. The removal of fluoride ions was maximum for the adsorbent dosage of SP is 50mg/50ml. The fluoride adsorption was maximum at 60minutes. The adsorption of F- ion was maximum in the shaking speed of 120 rpm. The presence of interfering ions such as nitrate and carbonate showed positive effect while sulphate and chloride showed little negative effect and phosphate showed high negative effect for the adsorbent. The optimum initial fluoride concentration for SP adsorbent was 1mg/50ml.

  9. POTENTIAL USE OF WOOL WASTE AS ADSORBENT FOR THE REMOVAL OF ACID DYES FROM WASTEWATER

    BUCIŞCANU Ingrid

    2016-05-01

    Full Text Available At present, great amounts of raw wool are treated as waste and raise disposal problems. In the sustainable development context , wool is regarded as a biodegradable renewable resource and due to its complex chemical composition and fiber morphology, can find different useful applications. It is the aim of this paper to investigate the potential use of raw wool waste as a non-conventional adsorbent for Acid Red 337(AcR ,currently used for leather and wool dyeing. Two wool-based adsorbents were prepared, namely scoured coarse wool (Wool-S and wool activated with alcoholic solution of sodium hydroxide (Wool-A. Adsorbent dosage, dye concentration, pH and treatment time were factors taken in consideration for the assessment of the sorbate-adsorbent interaction. The removal efficiency (R % is mainly dependent on the solution pH and on the activation treatment applied to wool: at pH 3, the removal efficiency reaches the highest values of 42% on Wool-S and 99% on Wool-A. The adsorption rate is slow and needs almost 6 h to reach equilibrium. The experimental data best fitted the Langmuir equilibrium adsorption model, which proves that the adsorbent possess surface active sites to which the dye sorbate binds in monomolecular layer. Raw wool waste is a potential cheap, biodegradable and effective adsorbent for colored wastewater treatment.

  10. Production of adsorbent from palm shell for radioactive iodine scrubbing process

    The biggest biomass source in Malaysia comes from oil palm industry. According to the statistic of year 2004, Malaysia produced 40 million tones per year of biomass which 30 million tones of biomass originated from the oil palm industries. Therefore, the biomass waste such as palm kernel shell can be used to produce granular adsorbent for radioactive materials. For that reason, a newly system, called Rocking Kiln - Fluidized Bed (RK - FB) was developed to utilize large amount of the biomass to produce high value added product. Charcoal or chemically produced activated carbon could be produced by using the kiln. Washing process was introduced to remove particles, minerals and volatile matters from charcoal produced and then would create more surface area in the adsorbent by creating more active sites. In this research, the adsorbent produced was used to scrub iodine 131. In nuclear power reactor, iodine isotope 131 is produced during nuclear fission, and this elementary radioactive iodine may pollute exhaust air streams that could cause thyroid cancer. For removal of radioactive iodine, normally a potassium iodide - impregnated activated carbon (KI - AC) is used. Thus, a process will be developed to produce KI - AC and this product will be used to calculate the efficiency to remove the radioactive iodine 131.The results obtain show that adsorbent produced has a high potential to be used in radioactive adsorbing and likely more economics. This paper will elaborate further the experimental set-up of in Kiln - Fluidized Bed (RK - FB), adsorbent quality and radioactive scrubbing process. (author)

  11. Process for producing zeolite adsorbent and process for treating radioactive liquid waste with the zeolite adsorbent

    Zeolite is contacted with an aqueous solution containing at least one of copper, nickel, cobalt, manganese and zinc salts, preferably copper and nickel salts, particularly preferably copper salt, in such a form as sulfate, nitrate, or chloride, thereby adsorbing the metal on the zeolite in its pores by ion exchange, then the zeolite is treated with a water-soluble ferrocyanide compound, for example, potassium ferrocyanide, thereby forming metal ferrocyanide on the zeolite in its pores. Then, the zeolite is subjected to ageing treatment, thereby producing a zeolite adsorbent impregnated with metal ferrocyanide in the pores of zeolite. The adsorbent can selectively recover cesium with a high percent cesium removal from a radioactive liquid waste containing at least radioactive cesium, for example, a radioactive liquid waste containing cesium and such coexisting ions as sodium, magnesium, calcium and carbonate ions at the same time at a high concentration. The zeolite adsorbent has a stable adsorbability for a prolonged time

  12. Distribution of metal and adsorbed guest species in zeolites

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes 129Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of 129Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, 129Xe NMR is insensitive to fine structural details at room temperature

  13. Distribution of metal and adsorbed guest species in zeolites

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  14. AMMONIA AND COD REMOVAL FROM SYNTHETIC LEACHATE USING RICE HUSK COMPOSITE ADSORBENT

    Azhar Abdul Halim

    2011-06-01

    Full Text Available Ammonia and chemical oxygen demand (COD were the most two problematic parameters in the landfill leachate. In this study, a new composite adsorbent derived from rice husk ash waste is evaluated with respect to its ability to remove these contaminants from synthetic leachate. Results indicate that the new composite adsorbent is able to adsorb both ammonia and COD. It has a higher adsorption capacity for ammonia (Q = 2.2578 mg/g and an almost equal adsorption capacity for COD (Q = 2.8893 when compared with commercially activated carbon. The adsorption kinetics of this new product for ammonia and COD were primarily represented by the pseudo second-order mechanism. The overall adsorption rate of the ammonia and COD adsorption processes appears to be determined by chemisorption process. The regenerated composite adsorbent indicated higher adsorption capacities of ammonia and COD, i.e. 12.9366 mg/g and 3.1162 mg/g, respectively.

  15. ADSORPTION OF PHENOLIC COMPOUNDS ONTO THE SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    XuMingcheng; XUMancai; 等

    2000-01-01

    Adsorption of phenol,catechol and resorcinol,which vary in their ability to interact with the adsorbent through hydrogen bond,were used to investigate the adsorption mechanistic interaction.The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out.The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity.On the other hand,the more of the groups available for hydrogen bond interaction,the higher of the adsorption affinity.These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.

  16. Evaluation of optimal silver amount for the removal of methyl iodide on silver-impregnated adsorbents

    The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver-impregnated zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver impregnation amount for the removal of methyl iodide at temperatures up to 300 deg. C. The degree of adsorption efficiency of methyl iodide on silver-impregnated adsorbent is strongly dependent on impregnation amount and process temperature. A quantitative comparison of adsorption efficiencies on three adsorbents in a fixed bed was investigated. The influence of temperature, methyl iodide concentration and silver impregnation amount on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It shows that the effective impregnation ratio was about 10wt%, based on the degree of silver utilization for the removal of methyl iodide. The practical applicability of silver-impregnated zeolite for the removal of radioiodine generated from the DUPIC process was consequently proposed. (author)

  17. Electrically Conductive Multiphase Polymer Blend Carbon-Based Composites

    Brigandi, Paul James

    The use of multiphase polymer blends provides unique morphologies and properties to reduce the percolation concentration and increase conductivity of carbon-based polymer composites. These systems offer improved conductivity, temperature stability and selective distribution of the conductive filler through unique morphologies at significantly lower conductive filler concentration. In this work, the kinetic and thermodynamic effects on a series of multiphase conductive polymer composites were investigated. The polymer blend phase morphology, filler distribution, electrical conductivity, and rheological properties of CB-filled PP/PMMA/EAA conductive polymer composites were determined. Thermodynamic and kinetic parameters were found to influence the morphology development and final composite properties. The morphology and CB distribution were found to be kinetically driven when annealed for a short period of time following the shear-intensive mixing process, whereas the three-phase polymer blend morphology is driven by thermodynamics when given sufficient time under high temperature annealing conditions in the melt state. At short annealing times, the CB distribution was influenced by the compounding sequence where the CB was added after being premixed with one of the polymer phases or directly added to the three phase polymer melt, but again was thermodynamically driven at longer annealing times with the CB migrating to the EAA phase. The resistivity was found to decrease by a statistically significant amount to similar levels for all of the composite systems with increasing annealing time, providing evidence of gradual phase coalescence to a tri-continuous morphology and CB migration. The addition of CB via the PP and EAA masterbatch results in significantly faster percolation and lower resistivity compared to when added direct to the system during compounding after 30 minutes annealing by a statistically significant amount. Dynamic oscillatory shear rheology using

  18. Thorium removal by different adsorbents

    Metaxas, Michail; Kasselouri-Rigopoulou, Vasilia; Galiatsatou, Polymnia; Konstantopoulou, Cathrine; Oikonomou, Dimitrios

    2003-02-28

    The removal of radiotoxic Th{sup 4+} from aqueous solutions has been explored using two different groups of adsorptive materials (e.g. two activated carbons and four zeolites--two natural and two synthetic). The activated carbons were prepared from solvent extracted olive pulp (SEOP) and olive stone (OS) by a two-step physical activation method with steam. They were characterized by N{sub 2} at 77 K adsorption, Hg porosimetry and by determination of their iodine number. All carbons prepared are of the H-type (e.g. contain mainly basic surface oxides) confirmed by the results of the Boehm's method. The natural zeolites, clinoptilolite (NaCLI) and mordenite (NaMOR), were pretreated with Na{sup +} before the adsorption experiments, while the synthetic ones, NaX and NaA, were provided in their commercial sodium form. The natural zeolites, NaCLI and NaMOR, utilized 11.5 and 38.6% of the theoretical ion-exchange capacity, based on Al content, respectively, while NaX and NaA utilized 41.5 and 45.9%, respectively. The activated carbons showed better removal capability than NaCLI. NaMOR, showed comparable results to the carbon originated from OS, but lower removal capability than the carbon originated from SEOP. The synthetic zeolites showed the highest removal ability for thorium ions due to their increased ion-exchange capacity because of their cleaner and larger framework channels and their higher number of ion-exchange sites. The carbons adsorption capacity mainly depends on the content and nature of functional surface groups. The adsorption data were fitted to Langmuir and Freundlich models. The former achieved best fits and was further applied to obtain the respective Langmuir constant and maximum adsorption capacity for each system.

  19. [Preparation of adsorbent made from sewage sludge and its spectrum properties].

    Yu, Lan-Lan; Zhong, Qin; Feng, Lan-Lan

    2006-05-01

    Biochemical sludges of sewage and petrochemistry and surplus sludge were taken as raw materials to prepare adsorbents for flue gas desulfurization by pyrolysis. To compare with active carbon, the abilities of adsorbents made from different sludges were studied by SEM, X-ray diffraction diagram, TG and DTA, pore characteristics and elements analysis, and the adsorption mechanisms of systems of SO2 -O2-N2 and SO2-O2-H2O(g)-N2 were studied by FTIR. Results indicated that the desulfurization performance of adsorbent made from surplus sludge was better, subsequent was petrochemical sludge, and the adsorbent made from biochemical sludge of sewage was worse. The desulfurization efficiency of adsorbent made from surplus sludge was slightly lower than active carbon. In the system of SO2-O2-N2, physical adsorption was primary, but in the condition of water, chemical adsorption was primary, where catalysis and oxidation of SO2 took place in sludge-derived adsorbent. In adsorption process, the adsorption depends on micropore structure. PMID:16883862

  20. Carbon-based acid catalyst from waste seed shells: preparation and characterization

    Wang Li H.

    2015-12-01

    Full Text Available A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized seed shells of Jatropha curcas (J. curcas L.. The structure of amorphous carbon consisting of polycyclic aromatic carbon sheets attached a high density of acidic SO3H groups (2.0 mmol · g−1 was identified with scanning electron microscopy (SEM, fourier transform infrared (FTIR spectroscopy, powder X-ray diffraction (XRD, and X-ray photoelectron spectroscopy (XPS. The performance of the solid acid catalyst was evaluated for biodiesel production in the esterification of oleic acid with methanol. 95.7% yield of biodiesel was obtained after 2 h reaction and the conversions with reused catalyst varied in the range of 95.7% to 95.1%, showing better activity and stability than commercial catalyst amberlyst-46. It was also observed that the prepared catalyst showed enhanced activity in the transesterification of triolein with methanol when compared with other solid acid catalysts. A synergistic effect results from the high density of SO3H groups and the good access of reactants to the acidic sites can be used to explain the excellent catalytic activity, as well as the strong affinity between the hydrophilic reactants and the neutral OH groups bonded to the polycyclic aromatic carbon rings.

  1. Use of grape must as a binder to obtain activated carbon briquettes

    A. C. Deiana

    2004-12-01

    Full Text Available The results of studies on briquetting activated-carbon-based adsorbent materials, prepared from raw materials from the region of Cuyo, Argentina, are reported in this article. Several steps were carried out to obtain activated-carbon briquettes from Eucalyptus camaldulensis Dehn wood. These steps included carbonization of wood to obtain char; blending of char and a novel binder, i.e., grape must; formation of cylinder-like briquettes by pressure; and activation of the resulting material. The material was activated with steam under different temperatures, activation times, and activating agent flow rates. Impact resistance index, axial compressive strength, tensile strength by diametrical compression, BET area, and pore volume were measured for product characterization. Satisfactory surface areas and mechanical strengths were found in the final products.

  2. Effect of Adsorbent Diameter on the Performance of Adsorption Refrigeration

    黄宏宇; 何兆红; 袁浩然; 小林敬幸; 赵丹丹; 窪田光宏; 郭华芳

    2014-01-01

    Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can af-fect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.

  3. Improvement in Superconducting Properties of MgB2 Superconductors by Nanoscale Carbon-Based Compound Doping

    Si-Hai Zhou

    2008-01-01

    MgB2 is a relatively new superconductor; it has attracted great interest from superconductor researchers all over the world. Thorough investigations have been carried out to study the material fabrication, as well as to study the material and superconducting properties from a fundamental physics point of view. The University of Wollongong has played a very active role in this research and a leading role in the research on high critical current density and high critical magnetic fields. Our recent research on the improve- ment of critical current density and the upper critical magnetic field by carbon-based compound doping is reviewed in this paper.

  4. ADSORPTION OF Cr(VI FROM AQUEOUS SOLUTION USING CARBON-MICROSILICA COMPOSITE ADSORBENT

    DEYI ZHANG

    2012-03-01

    Full Text Available In this work, Microsilica, one kind of industry solid waste material, was utilized firstly to prepare a carbon-Microsilica composite adsorbent from a partial carbonization, mixture and sulfoxidation process and was proposed for the removal of Cr(VI from solutions. The surface chemistry characteristics of the prepared adsorbent were analysis by XPS and FT-IR. The characterization results indicated that an abundant of oxygen functional groups, such as hydroxyl, carboxyl and sulfonic groups, were introduced into the surface of the prepared composite adsorbent. Meanwhile, the adsorption characteristics of Cr(VI onto the adsorbent in aqueous solutions was studied as a function of solution pH, ionic strength, contact time, and temperature. The results showed that Cr(VI adsorption onto the adsorbent is strongly dependent on pH and, to a lesser extent, ionic strength. Kinetics data were found to follow the pseudo-second-order kinetic model while the adsorption data corresponded to L-shape adsorption isotherm which corresponds to the classification of Giles. Activation thermodynamic parameters, such as activation enthalpy (ΔH*, activation entropy (ΔS*, activation Gibbs free energy (ΔG* and activation energy (E, have been evaluated and the possible adsorption mechanism also was suggested.

  5. The Dynamics and Structures of Adsorbed Surfaces

    Nielsen, M; Ellenson, W. D.; McTague, J. P.

    1978-01-01

    Reviews neutron scattering work performed on films of simple gas atoms and molecules adsorbed primarily on graphite surfaces. Exfoliated graphite substrates such as Grafoil were first used in this kind of measurements about five years ago and new results have been reported at an increasing pace. ...

  6. Antiferromagnets Structure in Adsorbed O2 Monolayers

    Nielsen, Mourits; McTague, J. P.

    1977-01-01

    Neutron diffraction from monolayers of O2 adsorbed on graphite shows structural arrangements similar to the dense planes of bulk O2. At monolayer completion and above, a magnetic superlattice reflection shows well-developed antiferromagnetic order for T ⩽ 10 K. The submonolayer phase also shows...

  7. Organosilicon Ion-Exchange and Complexing Adsorbents

    M. Voronkov; N. Vlasova; Yu. Pozhidaev; L. Belousova

    2005-01-01

    @@ 1Introduction Modification of mineral synthetic or natural substrates by organosilicon G-functionally substituted monomers, copolycondensation of the latter with organic and organosilicon compounds, and hydrolytic polycondensation of these monomers are the most widely used methods of synthesis of organosilicon adsorbents.

  8. Analysis of carbon based materials under fusion relevant thermal loads

    Carbon based materials (CBMs) are used in fusion devices as plasma facing materials for decades. They have been selected due to the inherent advantages of carbon for fusion applications. The main ones are its low atomic number and the fact that it does not melt but sublimate (above 3000 C) under the planned working conditions. In addition, graphitic materials retain their mechanical properties at elevated temperatures and their thermal shock resistance is one of the highest, making them suitable for thermal management purpose during long or extremely short heat pulses. Nuclear grade fine grain graphite was the prime form of CBM which was set as a standard but when it comes to large fusion devices created nowadays, thermo-mechanical constraints created during transient heat loads (few GW.m-2 can be deposited in few ms) are so high that carbon/carbon composites (so-called Carbon Fiber Composites (CFCs)) have to be utilized. CFCs can achieve superior thermal conductivity as well as mechanical properties than fine grain graphite. However, all the thermo-mechanical properties of CFCs are highly dependent on the loading direction as a consequence of the graphite structure. In this work, the background on the anisotropy of the graphitic structures but also on the production of fine grain graphite and CFCs is highlighted, showing the major principles which are relevant for the further understanding of the study. Nine advanced CBMs were then compared in terms of microstructure and thermo-mechanical properties. Among them, two fine grain graphites were considered as useful reference materials to allow comparing advantages reached by the developed CFCs. The presented microstructural investigation methods permitted to make statements which can be applied for CFCs presenting similarities in terms of fiber architecture. Determination of the volumetric percentage of the major sub-units of CFCs, i.e. laminates, felt layers or needled fiber groups, lead to a better understanding on

  9. Controllable Catalysis with Nanoparticles: Bimetallic Alloy Systems and Surface Adsorbates

    Chen, Tianyou

    2016-05-16

    Transition metal nanoparticles are privileged materials in catalysis due to their high specific surface areas and abundance of active catalytic sites. While many of these catalysts are quite useful, we are only beginning to understand the underlying catalytic mechanisms. Opening the “black box” of nanoparticle catalysis is essential to achieve the ultimate goal of catalysis by design. In this Perspective we highlight recent work addressing the topic of controlled catalysis with bimetallic alloy and “designer” adsorbate-stabilized metal nanoparticles.

  10. Temperature programmed desorption of weakly bound adsorbates on Au(111)

    Engelhart, Daniel P.; Wagner, Roman J. V.; Meling, Artur; Wodtke, Alec M.; Schäfer, Tim

    2016-08-01

    We have performed temperature programmed desorption (TPD) experiments to analyze the desorption kinetics of Ar, Kr, Xe, C2H2, SF6, N2, NO and CO on Au(111). We report desorption activation energies (Edes), which are an excellent proxy for the binding energies. The derived binding energies scale with the polarizability of the molecules, consistent with the conclusion that the surface-adsorbate bonds arise due to dispersion forces. The reported results serve as a benchmark for theories of dispersion force interactions of molecules at metal surfaces.