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Sample records for membrane carbon adsorption

  1. Synthesis and characterization of ceramic/carbon nanotubes composite adsorptive membrane for copper ion removal from water

    Energy Technology Data Exchange (ETDEWEB)

    Tofighy, Maryam Ahmadzadeh; Mohammadi, Toraj [Iran University of Science and Technology (IUST), Tehran (Iran, Islamic Republic of)

    2015-02-15

    We prepared a novel adsorptive membrane by implanting carbon nanotubes (CNTs) in pore channels of ceramic (α-alumina) support via chemical vapor deposition (CVD) method using cyclohexanol and ferrocene as carbon precursor and catalyst, respectively. Optimization of CNTs growth conditions resulted in uniform distribution of the CNTs in the pore channels of the support. The optimized CNTs-ceramic membrane was oxidized with concentrated nitric acid, and chitosan was employed for filling intertube-CNT gaps. The modified CNTs-ceramic membrane was used for copper ion removal from water, and the effects of the modification steps (oxidation and filling intertube-CNT gaps with chitosan) and pH on permeation flux and rejection of the prepared adsorptive membrane were investigated. Moreover, static adsorption was also investigated and Langmuir and Freundlich isotherms and two kinetics models were used to describe adsorption behavior of copper ions by the prepared adsorptive membrane.

  2. Protective clothing based on permselective membrane and carbon adsorption

    International Nuclear Information System (INIS)

    Gottschlich, D.; Baker, R.

    1995-01-01

    This paper is a description of Phase I of the US DOE's program to develop improved protective clothing for use by workers engaged in decommissioning and decontamination of former DOE sites, including those used for atomic weapons research and production. Membrane Technology and Research has been developing the clothing with an innovative feature of an ultrathin, permselective outer membrane that is extremely permeable to water but impermeable to toxic organic compounds. Phase I (as described herein) includes fabric optimization, commercial-scale fabric production, and prototype suit evaluation. This phase is complete, with the results discussed in this document

  3. Protective clothing based on permselective membrane and carbon adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.

    1995-03-01

    The objective of this program is to develop improved protective clothing for use by workers engaged in decomissioning and decontamination of former DOE sites. The proposed technology concerns a new protective clothing fabric that combines a permselective membrane layer (for water transmission and breathability) with a sorptive layer.

  4. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

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

  5. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation.

    Science.gov (United States)

    Secondes, Mona Freda N; Naddeo, Vincenzo; Belgiorno, Vincenzo; Ballesteros, Florencio

    2014-01-15

    Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Secondes, Mona Freda N. [Environmental Engineering Graduate Program, Department of Chemical Engineering, University of the Philippines – Diliman, Quezon City (Philippines); Naddeo, Vincenzo, E-mail: vnaddeo@unisa.it [Sanitary and Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, Fisciano 84084 (Saudi Arabia) (Italy); Belgiorno, Vincenzo [Sanitary and Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, Fisciano 84084 (Saudi Arabia) (Italy); Ballesteros, Florencio [Environmental Engineering Graduate Program, Department of Chemical Engineering, University of the Philippines – Diliman, Quezon City (Philippines)

    2014-01-15

    Highlights: • Above 99% of the emerging contaminants were removed in the USAMe process. • Influence of PAC dose and US frequency on removal is studied. • Improved performance is due to PAC adsorption enhancement and sonolytic degradation. • US irradiation improved efficiency and delayed declines in the removal of contaminants. • Performance of the hybrid process is better under lower frequency ultrasound irradiation. -- Abstract: Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs.

  7. Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation

    International Nuclear Information System (INIS)

    Secondes, Mona Freda N.; Naddeo, Vincenzo; Belgiorno, Vincenzo; Ballesteros, Florencio

    2014-01-01

    Highlights: • Above 99% of the emerging contaminants were removed in the USAMe process. • Influence of PAC dose and US frequency on removal is studied. • Improved performance is due to PAC adsorption enhancement and sonolytic degradation. • US irradiation improved efficiency and delayed declines in the removal of contaminants. • Performance of the hybrid process is better under lower frequency ultrasound irradiation. -- Abstract: Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs

  8. Ozonation effect on natural organic matter adsorption and biodegradation--application to a membrane bioreactor containing activated carbon for drinking water production.

    Science.gov (United States)

    Treguer, Ronan; Tatin, Romuald; Couvert, Annabelle; Wolbert, Dominique; Tazi-Pain, Annie

    2010-02-01

    More stringent legislation on dissolved organic matter (DOM) urges the drinking water industry to improve in DOM removal, especially when applied to water with high dissolved organic carbon (DOC) contents and low turbidity. To improve conventional processes currently used in drinking water treatment plants (DWTPs), the performances of a hybrid membrane bioreactor containing fluidized activated carbon were investigated at the DWTP of Rennes. Preliminary results showed that the residual DOC was the major part of the non-biodegradable fraction. In order to increase the global efficiency, an upstream oxidation step was added to the process. Ozone was chosen to break large molecules and increase their biodegradability. The first step consisted of carrying out lab-scale experiments in order to optimise the necessary ozone dose by measuring the process yield, in terms of biodegradable dissolved organic carbon (BDOC). Secondly, activated carbon adsorption of the DOC present in ozonated water was quantified. The whole process was tested in a pilot unit under field conditions at the DWTP of Rennes (France). Lab-scale experiments confirmed that ozonation increases the BDOC fraction, reduces the aromaticity of the DOC and produces small size organic compounds. Adsorption tests led to the conclusion that activated carbon unexpectedly removes BDOC first. Finally, the pilot unit results revealed an additional BDOC removal (from 0.10 to 0.15 mg L(-1)) of dissolved organic carbon from the raw water considered. (c) 2009 Elsevier Ltd. All rights reserved.

  9. Adsorption of amylase enzyme on ultrafiltration membranes

    DEFF Research Database (Denmark)

    Beier, Søren; Enevoldsen, Ann Dorrit; Kontogeorgis, Georgios

    2007-01-01

    A method to measure the static adsorption on membrane surfaces has been developed and described. The static adsorption of an amylase-F has been measured on two different ultrafiltration membranes, both with a cut-off value of 10 kDa (a PES membrane and the ETNA10PP membrane, which is a surface-mo...... is independent of the membrane type. At higher concentrations of enzyme, concentration polarization effects can not be neglected. Therefore stagnant film theory and the osmotic pressure model can describe the dependency between flux and bulk concentration....

  10. Carbon nanomaterials for gas adsorption

    CERN Document Server

    Terranova, Maria Letizia

    2012-01-01

    Research in adsorption of gases by carbon nanomaterials has experienced considerable growth in recent years, with increasing interest for practical applications. Many research groups are now producing or using such materials for gas adsorption, storage, purification, and sensing. This book provides a selected overview of some of the most interesting scientific results regarding the outstanding properties of carbon nanomaterials for gas adsorption and of interest both for basic research and technological applications. Topics receiving special attention in this book include storage of H, purific

  11. A combined process of activated carbon adsorption, ion exchange resin treatment and membrane concentration for recovery of dissolved organics in pre-hydrolysis liquor of the kraft-based dissolving pulp production process.

    Science.gov (United States)

    Shen, Jing; Kaur, Ishneet; Baktash, Mir Mojtaba; He, Zhibin; Ni, Yonghao

    2013-01-01

    To recover dissolved organics in pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process, a new combined process concept of sequential steps of activated carbon adsorption, ion exchange resin treatment, and membrane concentration, was proposed. The removal of lignin in the PHL was achieved in the activated carbon adsorption step, which also facilitates the subsequent operations, such as the membrane filtration and ion exchange resin treatment. The ion exchange resin treatment resulted in the removal/concentration of acetic acid, which opens the door for acetic acid recovery. The membrane filtration is to recover/concentrate the dissolved sugars. The combined process resulted in the production of PHL-based concentrate with relatively high concentration of hemicellulosic sugars, i.e., 22.13%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Efficient Adsorption of Sulfamethazine onto Modified Activated Carbon: A Plausible Adsorption Mechanism.

    Science.gov (United States)

    Liu, Ying; Liu, Xiaohui; Dong, Wenping; Zhang, Lingli; Kong, Qiang; Wang, Weiliang

    2017-09-29

    Activated carbon (AC) was modified by FeCl 3 . Batch experiments were carried out to evaluate the characteristics of equilibrium, kinetics and thermodynamics of Sulfamethazine adsorption onto original and modified AC. The results showed that Fe 3+ treatment changed the surface area, pore volume and surface zeta potential and increased the number of surface oxygenic functional groups. The adsorption of Sulfamethazine on modified activated carbon (MAC) was significantly improved. Isotherm test results revealed that the adsorption isotherms of Sulfamethazine on MAC fit the Freundlich, Langmuir and Temkin equations well. The maximum adsorption quantity of Sulfamethazine on MAC was 17.2414 mg/g at 25 °C. The adsorption kinetics of Sulfamethazine on AC and MAC can be characterized by the pseudo-second-order model. The adsorption process was affected by membrane diffusion, surface adsorption and internal diffusion. The adsorption quantities of Sulfamethazine first increased and then decreased for pH between 3 and 10. The removal efficiencies decreased with increasing temperature, which is favorable for adsorption at low temperature. It was also found that the mechanisms of adsorption included micropore capture and electrostatic, hydrogen bonding, π-π electron donor-acceptor (EDA) and coordination interactions as well as other interactions.

  13. Kinetic and equilibrium studies of urea adsorption onto activated carbon: Adsorption mechanism

    OpenAIRE

    Kameda, Tomohito; Ito, Saya; Yoshioka, Toshiaki

    2017-01-01

    We found that activated carbon effectively removed urea from solution and that urea adsorption onto activated carbon followed a pseudo-second-order kinetic model. We classified the urea adsorption on activated carbon as physical adsorption and found that it was best described by the Halsey adsorption isotherm, suggesting that the multilayer adsorption of urea molecules on the adsorption sites of activated carbon best characterized the adsorption system. The mechanism of adsorption of urea by ...

  14. Carbon dioxide adsorption in graphene sheets

    Directory of Open Access Journals (Sweden)

    Ashish Kumar Mishra

    2011-09-01

    Full Text Available Control over the CO2 emission via automobiles and industrial exhaust in atmosphere, is one of the major concerns to render environmental friendly milieu. Adsorption can be considered to be one of the more promising methods, offering potential energy savings compared to absorbent systems. Different carbon nanostructures (activated carbon and carbon nanotubes have attracted attention as CO2 adsorbents due to their unique surface morphology. In the present work, we have demonstrated the CO2 adsorption capacity of graphene, prepared via hydrogen induced exfoliation of graphitic oxide at moderate temperatures. The CO2 adsorption study was performed using high pressure Sieverts apparatus and capacity was calculated by gas equation using van der Waals corrections. Physical adsorption of CO2 molecules in graphene was confirmed by FTIR study. Synthesis of graphene sheets via hydrogen exfoliation is possible at large scale and lower cost and higher adsorption capacity of as prepared graphene compared to other carbon nanostructures suggests its possible use as CO2 adsorbent for industrial application. Maximum adsorption capacity of 21.6 mmole/g was observed at 11 bar pressure and room temperature (25 ºC.

  15. Quest for anionic MOF membranes: Continuous sod -ZMOF membrane with Co2 adsorption-driven selectivity

    KAUST Repository

    Almaythalony, Bassem

    2015-02-11

    We report the fabrication of the first continuous zeolite-like metal-organic framework (ZMOF) thin-film membrane. A pure phase sod-ZMOF, sodalite topology, membrane was grown and supported on a porous alumina substrate using a solvothermal crystallization method. The absence of pinhole defects in the film was confirmed and supported by the occurrence of quantifiable time-lags, for all studied gases, during constant volume/variable pressure permeation tests. For both pure and mixed gas feeds, the sod-ZMOF-1 membrane exhibits favorable permeation selectivity toward carbon dioxide over relevant industrial gases such as H2, N2, and CH4, and it is mainly governed by favorable CO2 adsorption.

  16. Activated Carbon Preparation and Modification for Adsorption

    Science.gov (United States)

    Cao, Yuhe

    Butanol is considered a promising, infrastructure-compatible biofuel. Butanol has a higher energy content than ethanol and can be used in conventional gas engines without modifications. Unfortunately, the fermentation pathway for butanol production is restricted by its toxicity to the microbial strains used in the process. Butanol is toxic to the microbes, and this can slow fermentation rates and reduce butanol yields. Gas stripping technology can efficiently remove butanol from the fermentation broth as it is produced, thereby decreasing its inhibitory effects. Traditional butanol separation heavily depends on the energy intensive distillation method. One of the main issues in acetone-butanol-ethanol fermentation is that butanol concentrations in the fermentation broth are low, ranging from 1 to 1.2 percent in weight, because of its toxicity to the microorganisms. Therefore distillation of butanol is even worse than distillation of corn ethanol. Even new separation methods, such as solid- extraction methods involve adding substances, such as polymer resin and zeolite or activated carbon, to biobutanol fermentatioon broth did not achieve energy efficient separation of butanol due to low adsorption selectivity and fouling in broth. Gas-stripping - condensation is another new butanol recovery method, however, the butanol in gas-stripping stream is too low to be condensed without using expensive and energy intensive liquid nitrogen. Adsorption can then be used to recover butanol from the vapor phase. Activated carbon (AC) samples and zeolite were investigated for their butanol vapor adsorption capacities. Commercial activated carbon was modified via hydrothermal H2O2 treatment, and the specific surface area and oxygen-containing functional groups of activated carbon were tested before and after treatment. Hydrothermal H2O 2 modification increased the surface oxygen content, Brunauer-Emmett-Teller surface area, micropore volume, and total pore volume of active carbon

  17. Removal of heavy metals and pollutants by membrane adsorption techniques

    Science.gov (United States)

    Khulbe, K. C.; Matsuura, T.

    2018-03-01

    Application of polymeric membranes for the adsorption of hazardous pollutants may lead to the development of next-generation reusable and portable water purification appliances. Membranes for membrane adsorption (MA) have the dual function of membrane filtration and adsorption to be very effective to remove trace amounts of pollutants such as cationic heavy metals, anionic phosphates and nitrates. In this review article, recent progresses in the development of MA membranes are surveyed. In addition, recent progresses in the development of advanced adsorbents such as nanoparticles are summarized, since they are potentially useful as fillers in the host membrane to enhance its performance. The future directions of R&D in this field are also shown in the conclusion section.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-05

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

  19. Uranium preconcentration from seawater using adsorptive membranes

    International Nuclear Information System (INIS)

    Das, Sadananda; Pandey, A.K.; Manchanda, V.K.; Athawale, A.A.

    2009-01-01

    Uranium recovery from bio-aggressive but lean feed like seawater is a challenging problem as it requires in situ preconcentration of uranium in presence of huge excess of competing ions with fast sorption kinetics. In our laboratory, widely used amidoxime membrane (AO-membrane) was evaluated for uranium sorption under seawater conditions. This study indicated that AO-membrane was inherently slow because of the complexation chemistry involved in transfer of U(VI) from (UO 2 (CO 3 ) 3 ) 4 - to AO sites in membrane. In order to search better options, several chemical compositions of membrane were scanned for their efficacy for uranium preconcentration from seawater, and concluded that EGMP-membrane offers several advantages over AO-membrane. In this paper, the comparison of EGMP-membrane with AO-membrane for uranium sorption under seawater conditions has been reviewed. (author)

  20. Carbon dioxide adsorption in chemically activated carbon from sewage sludge.

    Science.gov (United States)

    de Andrés, Juan Manuel; Orjales, Luis; Narros, Adolfo; de la Fuente, María del Mar; Encarnación Rodríguez, María

    2013-05-01

    In this work, sewage sludge was used as precursor in the production of activated carbon by means of chemical activation with KOH and NaOH. The sludge-based activated carbons were investigated for their gaseous adsorption characteristics using CO2 as adsorbate. Although both chemicals were effective in the development of the adsorption capacity, the best results were obtained with solid NaOH (SBA(T16)). Adsorption results were modeled according to the Langmuir and Freundlich models, with resulting CO2 adsorption capacities about 56 mg/g. The SBA(T16) was characterized for its surface and pore characteristics using continuous volumetric nitrogen gas adsorption and mercury porosimetry. The results informed about the mesoporous character of the SBA(T16) (average pore diameter of 56.5 angstroms). The Brunauer-Emmett-Teller (BET) surface area of the SBA(T16) was low (179 m2/g) in comparison with a commercial activated carbon (Airpel 10; 1020 m2/g) and was mainly composed of mesopores and macropores. On the other hand, the SBA(T16) adsorption capacity was higher than that of Airpel 10, which can be explained by the formation of basic surface sites in the SBA(T16) where CO2 experienced chemisorption. According to these results, it can be concluded that the use of sewage-sludge-based activated carbons is a promising option for the capture of CO2. Adsorption methods are one of the current ways to reduce CO2 emissions. Taking this into account, sewage-sludge-based activated carbons were produced to study their CO2 adsorption capacity. Specifically, chemical activation with KOH and NaOH of previously pyrolyzed sewage sludge was carried out. The results obtained show that even with a low BET surface area, the adsorption capacity of these materials was comparable to that of a commercial activated carbon. As a consequence, the use of sewage-sludge-based activated carbons is a promising option for the capture of CO2 and an interesting application for this waste.

  1. Study of Methylene Blue adsorption on keratin nanofibrous membranes.

    Science.gov (United States)

    Aluigi, A; Rombaldoni, F; Tonetti, C; Jannoke, L

    2014-03-15

    In this work, keratin nanofibrous membranes (mean diameter of about 220nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models. A mean free energy evaluated through the Dubinin-Radushkevich model of about 16kJmol(-1), indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudo-second-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Optimising carbon electrode materials for adsorptive stripping voltammetry

    OpenAIRE

    Chaisiwamongkhol, K; Batchelor-McAuley, C; Sokolov, S; Holter, J; Young, N; Compton, R

    2017-01-01

    Different types of carbon electrode materials for adsorptive stripping voltammetry are studied through the use of cyclic voltammetry. Capsaicin is utilised as a model compound for adsorptive stripping voltammetry using unmodified and modified basal plane pyrolytic graphite (BPPG) electrodes modified with multi-walled carbon nanotubes, carbon black or graphene nanoplatelets, screen printed carbon electrodes (SPE), carbon nanotube modified screen printed electrodes, and carbon paste electrodes....

  3. The Adsorption Mechanism of Modified Activated Carbon on Phenol

    Directory of Open Access Journals (Sweden)

    Lin J. Q.

    2016-01-01

    Full Text Available Modified activated carbon was prepared by thermal treatment at high temperature under nitrogen flow. The surface properties of the activated carbon were characterized by Boehm titration, BET and point of zero charge determination. The adsorption mechanism of phenol on modified activated carbon was explained and the adsorption capacity of modified activated carbon for phenol when compared to plain activated carbon was evaluated through the analysis of adsorption isotherms, thermodynamic and kinetic properties. Results shows that after modification the surface alkaline property and pHpzc value of the activated carbon increase and the surface oxygen-containing functional groups decrease. The adsorption processes of the plain and modified carbon fit with Langmuir isotherm equation well, and the maximum adsorption capacity increase from 123.46, 111.11, 103.09mg/g to 192.31, 178.57, 163,93mg/g under 15, 25 and 35°C after modification, respectively. Thermodynamic parameters show that the adsorption of phenol on activated carbon is a spontaneously exothermic process of entropy reduction, implying that the adsorption is a physical adsorption. The adsorption of phenol on activated carbon follows the pseudo-second-order kinetics (R2>0.99. The optimum pH of adsorption is 6~8.

  4. High-Flux Carbon Molecular Sieve Membranes for Gas Separation.

    Science.gov (United States)

    Richter, Hannes; Voss, Hartwig; Kaltenborn, Nadine; Kämnitz, Susanne; Wollbrink, Alexander; Feldhoff, Armin; Caro, Jürgen; Roitsch, Stefan; Voigt, Ingolf

    2017-06-26

    Carbon membranes have great potential for highly selective and cost-efficient gas separation. Carbon is chemically stable and it is relative cheap. The controlled carbonization of a polymer coating on a porous ceramic support provides a 3D carbon material with molecular sieving permeation performance. The carbonization of the polymer blend gives turbostratic carbon domains of randomly stacked together sp 2 hybridized carbon sheets as well as sp 3 hybridized amorphous carbon. In the evaluation of the carbon molecular sieve membrane, hydrogen could be separated from propane with a selectivity of 10 000 with a hydrogen permeance of 5 m 3 (STP)/(m 2 hbar). Furthermore, by a post-synthesis oxidative treatment, the permeation fluxes are increased by widening the pores, and the molecular sieve carbon membrane is transformed from a molecular sieve carbon into a selective surface flow carbon membrane with adsorption controlled performance and becomes selective for carbon dioxide. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Hydrogen adsorption on partially oxidised microporous carbons

    International Nuclear Information System (INIS)

    J B Parra; C O Ania; C J Duran Valle; M L Sanchez; C Otero Arean

    2005-01-01

    The search for cost effective adsorbents for large scale gas separation, storage and transport constitutes a present day strategic issue in the energy sector, propelled mainly by the potential use of hydrogen as an energy vector in a sustainable (and cleaner) energy scenario. Both, activated carbons and carbon based nano-structured materials have been proposed as potential candidates for reversible hydrogen storage in cryogenically cooled vessels. For that purpose, surface modification so as to enhance the gas solid interaction energy is desirable. We report on hydrogen adsorption on microporous (active) carbons which have been partially oxidised with nitric acid and ammonium persulfate. From the corresponding hydrogen adsorption isotherms (Fig. 1) an isosteric heat of about 3 kJ mol -1 was derived. This value is in agreement with that of about 3 to 4 kJ mol -1 obtained by quantum chemical calculations on the interaction between the hydrogen molecule and simple model systems (Fig. 2) of both, hydroxyl and carboxyl groups. Further research is in progress with a view to further increases the gas solid interaction energy. However, the values so far obtained are significantly larger than the liquefaction enthalpy of hydrogen: 0.90 kJ mol -1 ; and this is relevant to both, hydrogen separation from gas mixtures and cryogenic hydrogen storage. (authors)

  6. Carbon membranes for efficient water-ethanol separation

    Science.gov (United States)

    Gravelle, Simon; Yoshida, Hiroaki; Joly, Laurent; Ybert, Christophe; Bocquet, Lydéric

    2016-09-01

    We demonstrate, on the basis of molecular dynamics simulations, the possibility of an efficient water-ethanol separation using nanoporous carbon membranes, namely, carbon nanotube membranes, nanoporous graphene sheets, and multilayer graphene membranes. While these carbon membranes are in general permeable to both pure liquids, they exhibit a counter-intuitive "self-semi-permeability" to water in the presence of water-ethanol mixtures. This originates in a preferred ethanol adsorption in nanoconfinement that prevents water molecules from entering the carbon nanopores. An osmotic pressure is accordingly expressed across the carbon membranes for the water-ethanol mixture, which agrees with the classic van't Hoff type expression. This suggests a robust and versatile membrane-based separation, built on a pressure-driven reverse-osmosis process across these carbon-based membranes. In particular, the recent development of large-scale "graphene-oxide" like membranes then opens an avenue for a versatile and efficient ethanol dehydration using this separation process, with possible application for bio-ethanol fabrication.

  7. Hydrogen adsorption in carbon nanostructures compared

    International Nuclear Information System (INIS)

    Schimmel, H.G.; Nijkamp, G.; Kearley, G.J.; Rivera, A.; Jong, K.P. de; Mulder, F.M.

    2004-01-01

    Recent reports continue to suggest high hydrogen storage capacities for some carbon nanostructures due to a stronger interaction between hydrogen and carbon. Here the interaction of hydrogen with activated charcoal, carbon nanofibers, single walled carbon nanotubes (SWNT), and electron beam 'opened' SWNT are compared and shown to be similar. The storage capacity below 77 K of these materials correlates with the surface area of the material with the activated charcoal having the largest. SWNT and 'opened' SWNT have a relatively low accessible surface area due to bundling of the tubes. Pressure-temperature curves give the interaction potential, which was found to be ∼580 K or 50 meV in all samples, leading to significant adsorption below ∼50 K. Using the inelastic neutron scattering signal associated with rotation of the hydrogen molecule as a sensitive probe for the surroundings of the molecule, no difference was found between the hydrogen molecules adsorbed in the investigated materials. These combined spectroscopic and macroscopic results show that SWNT, nanofibers and activated carbons store molecular hydrogen due to their graphitic nature and not because they possess special morphologies. Results from a density functional theory computer calculation suggest molecular hydrogen bonding to an aromatic C-C bond of graphite, irrespective of the surface morphology farther away

  8. Kinetic modelling and mechanism of dye adsorption on unburned carbon

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.B.; Li, H.T. [Curtin University of Technology, Perth, WA (Australia). Dept. of Chemical Engineering

    2007-07-01

    Textile dyeing processes are among the most environmentally unfriendly industrial processes by producing coloured wastewaters. The adsorption method using unburned carbon from coal combustion residue was studied for the decolourisation of typical acidic and basic dyes. It was discovered that the unburned carbon showed high adsorption capacity at 1.97 x 10{sup -4} and 5.27 x 10{sup -4} mol/g for Basic Violet 3 and Acid Black 1, respectively. The solution pH, particle size and temperature significantly influenced the adsorption capacity. Higher solution pH favoured the adsorption of basic dye while reduced the adsorption of acid dye. The adsorption of dye increased with increasing temperature but decreased with increasing particle size. Sorption kinetic data indicated that the adsorption kinetics followed the pseudo-second-order model. The adsorption mechanism consisted of two processes, external diffusion and intraparticle diffusion, and the external diffusion was the dominating process.

  9. Effect of Acid and Alcohol Network Forces within Functionalized Multiwall Carbon Nanotubes Bundles on Adsorption of Copper (II) Species

    Science.gov (United States)

    Adsorption of metals on carbon nanotubes (CNTs) has important applications in sensors, membranes, and water treatment. The adsorptive capacity of multiwall CNTs for copper species in water depends on the type of functional group present on their surface. The alcohol (COOH) and ac...

  10. Theoretical study of adsorption of lithium atom on carbon nanotube

    OpenAIRE

    Senami, Masato; Ikeda, Yuji; Fukushima, Akinori; Tachibana, Akitomo

    2011-01-01

    We investigate the adsorption of lithium atoms on the surface of the (12, 0) single wall carbon nanotube (SWCNT) by using ab initio quantum chemical calculations. The adsorption of one lithium atom on the inside of this SWCNT is favored compared to the outside. We check this feature by charge transfer and regional chemical potential density. The adsorption of multiple lithium atoms on the interior of the SWCNT is studied in terms of adsorption energy and charge transfer. We show that repulsiv...

  11. Adsorption performance of silver-loaded activated carbon fibers

    Directory of Open Access Journals (Sweden)

    Yan Xue-Feng

    2018-01-01

    Full Text Available Silver-loaded activated carbon fiber is prepared, and its adsorption performance is studied experimentally using five methylene blue solutions with different concentrations under three different temperature conditions. The adsorption tests show that fibers adsorption increase as the increase of temperature, and there is an optimal value for solution concentration, beyond which its adsorption will de-crease. Fibers isothermal adsorption to methylene blue is different from those by the monolayer adsorption by Langmuir model and the multilayer adsorption by Freundlich model. Through the analysis of thermodynamic parameters, Gibbs free energy, standard entropy, and standard enthalpy, it is found that the fibers adsorption to methylene blue is an exothermic process of physical adsorption.

  12. Adsorption of light alkanes on coconut nanoporous activated carbon

    Directory of Open Access Journals (Sweden)

    K. S. Walton

    2006-12-01

    Full Text Available This paper presents experimental results for adsorption equilibrium of methane, ethane, and butane on nanoporous activated carbon obtained from coconut shells. The adsorption data were obtained gravimetrically at temperatures between 260 and 300K and pressures up to 1 bar. The Toth isotherm was used to correlate the data, showing good agreement with measured values. Low-coverage equilibrium constants were estimated using virial plots. Heats of adsorption at different loadings were also estimated from the equilibrium data. Adsorption properties for this material are compared to the same properties for BPL activated carbon and BAX activated carbon.

  13. utilization of adsorption and/or liquid membranes techniques in treatment of some hazardous substances

    International Nuclear Information System (INIS)

    Hussin, L.M.S.

    2011-01-01

    environmental pollution, as a consequence of the industrialization process, is one of the major problems that has to be solved and controlled. The most important treatment processes for metals and dyes contaminated waste streams include chemical precipitation, membrane, filtration, ion exchange, carbon adsorption and coprecipitation/adsorption. However, all these techniques have their inherent advantages and limitations in applications. These processes usually need expensive facility and high maintenance cost. Therefore, there is a need for more economical alternative technologies for the treatment of metals and dyes contaminated waste streams. The aim of present work is to study the treatment of some hazardous substances such as heavy metals e.g. ( lead, cobalt and strontium) and dyes e.g. ( acid red 73, and acid blue 74 ) using either adsorption or liquid emulsion membrane techniques. The experimental part deals with the application of adsorption and liquid emulsion membrane techniques for removal of some hazardous substances such as metal ions ( lead, cobalt and strontium) and dyes (acid red 73 and acid blue 74). All the apparatus and techniques employed were described.

  14. Removal of paraquat and linuron from water by continuous flow adsorption/ ultrafiltration membrane processes

    International Nuclear Information System (INIS)

    Zahoor, M.

    2013-01-01

    The magnetic activated carbon (MAC) was prepared, characterized and compared with powdered activated carbon (PAC) for its adsorptive parameters. Both adsorbents were then used in combination ultrafiltration (UF) membrane as pretreatment for the removal of paraquat and linuron from water. The comparison of membrane parameters like percent retention, permeate flux and backwash times for PAC/UF and MAC/UF hybrid processes showed that percent retention of paraquat and linuron was high for PAC due to its high surface area. However due to cake formation over membrane surface the decline permeate fluxes and long backwash times for PAC were observed. PAC also caused blackening of pipes and flow meter. MAC (an iron oxide and PAC composite) was removed from slurry through magnet thus no cake formation and secondary problems observed for PAC was not encountered. Also the backwash times were minimum for MAC/UF process. (author)

  15. Adsorption facility and adsorption vessel for radioactive carbon dioxide

    International Nuclear Information System (INIS)

    Harashina, Heihachi; Miwa, Keiichi; Kobayashi, Takeo.

    1992-01-01

    If 14 CO 2 gas-containing gases to be adsorbed are pressurized and sent to a packaging adsorption means, CO 2 ingredient in the gases to be adsorbed is adsorbed or absorbed, and remaining gases are passed through and sent out to downstream. CO 2 adsorption or absorption of the packaging adsorption means is judged by monitoring the state of the remaining gases, and if it is normal, remaining gases are sent further to downstream and processed. If abnormality is found, a gas feedback system is operated, and CO 2 removing gas is sent again to the packaging adsorption means, in which CO 2 gases are adsorbed or absorbed again repeatingly. With such procedures, in a case where C 14 nuclides having a long half decay time are supplied in the form of 14 CO 2 gas, they are efficiently adsorbed or absorbed in the packaging system to improve removing and storing property of 14 C nuclides. (T.M.)

  16. Gas adsorption in active carbons and the slit-pore model 1: Pure gas adsorption.

    Science.gov (United States)

    Sweatman, M B; Quirke, N

    2005-05-26

    We describe procedures based on the polydisperse independent ideal slit-pore model, Monte Carlo simulation and density functional theory (a 'slab-DFT') for predicting gas adsorption and adsorption heats in active carbons. A novel feature of this work is the calibration of gas-surface interactions to a high surface area carbon, rather than to a low surface area carbon as in all previous work. Our models are used to predict the adsorption of carbon dioxide, methane, nitrogen, and hydrogen up to 50 bar in several active carbons at a range of near-ambient temperatures based on an analysis of a single 293 K carbon dioxide adsorption isotherm. The results demonstrate that these models are useful for relatively simple gases at near-critical or supercritical temperatures.

  17. Amine-functionalized PVA-co-PE nanofibrous membrane as affinity membrane with high adsorption capacity for bilirubin.

    Science.gov (United States)

    Wang, Wenwen; Zhang, Hao; Zhang, Zhifeng; Luo, Mengying; Wang, Yuedan; Liu, Qiongzhen; Chen, Yuanli; Li, Mufang; Wang, Dong

    2017-02-01

    In this study, poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane was activated by sodium hydroxide and cyanuric chloride, and then the activated membranes were functionalized by 1,3-propanediamine, hexamethylenediamine and diethylenetriamine to be affinity membranes for bilirubin removal, respectively. The chemical structures and morphologies of membranes were investigated by SEM, FTIR and XPS. And the adsorption ability of different amine-functionalized nanofibrous membranes for bilirubin was characterized. Furthermore, the effects of temperature, initial concentration of bilirubin, NaCl concentration and BSA concentration on the adsorption capacity for bilirubin of diethylenetriamine-functionalized nanofibrous membrane were studied. Results indicated that the adsorption capacity for bilirubin of diethylenetriamine-functionalized nanofibrous membrane could reach 85mg/g membrane when the initial bilirubin concentration was 200mg/L while the adsorption capacity could be increased to 110mg/g membrane if the initial bilirubin concentration was more than 400mg/L. The dynamic adsorption of diethylenetriamine-functionalized nanofibrous membrane showed that the ligands of amine groups on the membrane surface could be used as far as possible by recirculating the plasma with certain flow rates. Therefore, the diethylenetriamine-functionalized PVA-co-PE nanofibrous membrane possessed high adsorption capacity for bilirubin and it can be candidate as affinity membrane for bilirubin removal. Copyright © 2016. Published by Elsevier B.V.

  18. ADSORPTION OF STRONTIUM IONS FROM WATER ON MODIFIED ACTIVATED CARBONS

    Directory of Open Access Journals (Sweden)

    Mihai Ciobanu

    2016-12-01

    Full Text Available Adsorption of strontium ions from aqueous solutions on active carbons CAN-7 and oxidized CAN-8 has been studied. It has been found that allure of the adsorption isotherms for both studied active carbons are practically identical. Studies have shown that the adsorption isotherms for strontium ions from aqueous solutions are well described by the Langmuir and Dubinin-Radushkevich equations, respectively. The surface heterogeneity of activated carbons CAN-7 and oxidized CAN-8 has been assessed by using Freundlich equation.

  19. Influence of different carbon monolith preparation parameters on pesticide adsorption

    Directory of Open Access Journals (Sweden)

    Vukčević Marija

    2013-01-01

    Full Text Available The capacity of carbon monolith for pesticide removal from water, and the mechanism of pesticide interaction with carbon surface were examined. Different carbon monolith samples were obtained by varying the carbonization and activation parameters. In order to examine the role of surface oxygen groups in pesticide adsorption, carbon monolith surface was functionalized by chemical treatment in HNO3, H2O2 and KOH. The surface properties of the obtained samples were investigated by BET surface area, pore size distribution and temperature-programmed desorption. Adsorption of pesticides from aqueous solution onto activated carbon monolith samples was studied by using five pesticides belonging to different chemical groups (acetamiprid, dimethoate, nicosulfuron, carbofuran and atrazine. Presented results show that higher temperature of carbonization and the amount of activating agent allow obtaining microporous carbon monolith with higher amount of surface functional groups. Adsorption properties of the activated carbon monolith were more readily affected by the amount of the surface functional groups than by specific surface area. Results obtained by carbon monolith functionalisation showed that π-π interactions were the main force for adsorption of pesticides with aromatic structure, while acidic groups play an important role in adsorption of pesticides with no aromatic ring in the chemical structure.

  20. Study of lead adsorption on activated carbons | Kouakou ...

    African Journals Online (AJOL)

    Powder and granular activated carbons showed different adsorption capacity. The amount of Pb2+ adsorbed reached44.58, 38.96 and 39.06 mg/g for CPA, CGA 830 and CGA 1230 respectively at 25 °C. Langmuir and Freundlich adsorption models were used to represent the equilibrium data. Despite the high value of ...

  1. Adsorption of dyes onto activated carbon cloth: using QSPRs as tools to approach adsorption mechanisms.

    Science.gov (United States)

    Metivier-Pignon, Hélène; Faur, Catherine; Le Cloirec, Pierre

    2007-01-01

    The present study aimed to investigate the adsorption of dyes onto activated carbon cloths. Kinetics and isotherms were studied based on results of batch reactors to constitute databases for the adsorption rates and capacities of 22 commercial dyes. Added to a qualitative analysis of experimental results, quantitative structure property relationships (QSPRs) were used to determine the structural features that influence most adsorption processes. QSPRs consisted of multiple linear regressions correlating adsorption parameters with molecular connectivity indices (MCIs) as molecular descriptors. Results related to adsorption kinetics showed that the size of molecules was the significant feature, the high order MCIs involved in QSPRs indicating the influence of a critical size on adsorption rate. Improved statistical fits were obtained when the database was divided according to the chemical classes of dyes. As regards to adsorption isotherms, their particular form led to the use of saturation capacity as the adsorption parameter. By contrast with adsorption kinetics, molecular overcrowding seemed to be of less influence on adsorption equilibrium. In this case, MCIs included in the QSPR were more related to details of the molecular structure. The robustness of the QSPR assessed for azo dyes was studied for the other dyes. Although the small size of the database limited predictive ability, features relevant to the influence of the database composition on QSPRs have been highlighted.

  2. Phenol adsorption by activated carbon produced from spent coffee grounds.

    Science.gov (United States)

    Castro, Cínthia S; Abreu, Anelise L; Silva, Carmen L T; Guerreiro, Mário C

    2011-01-01

    The present work highlights the preparation of activated carbons (ACs) using spent coffee grounds, an agricultural residue, as carbon precursor and two different activating agents: water vapor (ACW) and K(2)CO(3) (ACK). These ACs presented the microporous nature and high surface area (620-950 m(2) g(-1)). The carbons, as well as a commercial activated carbon (CAC) used as reference, were evaluated as phenol adsorbent showing high adsorption capacity (≈150 mg g(-1)). The investigation of the pH solution in the phenol adsorption was also performed. The different activating agents led to AC with distinct morphological properties, surface area and chemical composition, although similar phenol adsorption capacity was verified for both prepared carbons. The production of activated carbons from spent coffee grounds resulted in promising adsorbents for phenol removal while giving a noble destination to the residue.

  3. Adsorption Equilibria of Acetic Acid on Activated Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyong-Mok; Nam, Hee-Geun; Mun, Sungyong [Hanyang University, Seoul (Korea, Republic of)

    2015-02-15

    In this study, the adsorption equilibria of acetic acid on activated carbon were investigated at the temperatures of 313.15 K and 323.15 K. The obtained adsorption data were then fitted by Langmuir, Bi-Langmuir, and Freundlich models, in which the relevant model parameters were determined by minimizing the sum of the squares of deviations between experimental data and calculated values. The comparison results revealed that Bi-Langmuir model could account for the adsorption equilibrium data of acetic acid with the highest accuracy among the three adsorption models considered.

  4. Theoretical study of adsorption of lithium atom on carbon nanotube

    Directory of Open Access Journals (Sweden)

    Masato Senami

    2011-12-01

    Full Text Available We investigate the adsorption of lithium atoms on the surface of the (12,0 single wall carbon nanotube (SWCNT by using ab initio quantum chemical calculations. The adsorption of one lithium atom on the inside of this SWCNT is favored compared to the outside. We check this feature by charge transfer and regional chemical potential density. The adsorption of multiple lithium atoms on the interior of the SWCNT is studied in terms of adsorption energy and charge transfer. We show that repulsive force between lithium atoms destabilizes a system for the large number of lithium atoms.

  5. Novel adsorptive ultrafiltration membranes derived from polyvinyltetrazole-co-polyacrylonitrile for Cu(II) ions removal

    KAUST Repository

    Kumar, Mahendra

    2016-05-04

    Novel adsorptive ultrafiltration membranes were manufactured from synthesized polyvinyltetrazole−co−polyacrylonitrile (PVT−co−PAN) by nonsolvent induced phase separation (NIPS). PVT−co−PAN with various degree of functionalization (DF) was synthesized via a [3+2] cycloaddition reaction at 60°C using a commercial PAN. PVT−co−PAN with varied DF was then explored to prepare adsorptive membranes. The membranes were characterized by surface zeta potential and static water contact angle measurements, scanning electron microscopy as well as atomic force microscopy (AFM) techniques. It was shown that PVT segments contributed to alter the pore size, charge and hydrophilic behavior of the membranes. The membranes became more negatively charged and hydrophilic after addition of PVT segments. The PVT segments in the membranes served as the major binding sites for adsorption of Cu(II) ions from aqueous solution. The maximum adsorption of Cu(II) ions by the membranes in static condition and in a continuous ultrafiltration of 10 ppm solution was attained at pH = 5. The adsorption data suggest that the Freundlich isotherm model describes well Cu(II) ions adsorption on the membranes from aqueous solution. The adsorption capacity obtained from the Freundlich isotherm model was 44.3 mg g−1; this value is higher than other membrane adsorption data reported in the literature. Overall, the membranes fabricated from PVT−co−PAN are attractive for efficient removal of heavy metal ions under the optimized conditions.

  6. Development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Syed Mohd Saufi

    2002-11-01

    Full Text Available This paper reports the development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane. Nitrogen was used as an inert gas during pyrolysis of the PAN hollow fiber membrane into carbon membrane. PAN membranes were pyrolyzed at temperature ranging from 500oC to 800oC for 30 minutes of thermal soak time. Scanning Electron Microscope (SEM, Fourier Transform Infrared Spectroscopy (FTIR and gas sorption analysis were applied to characterize the PAN based carbon membrane. Pyrolysis temperature was found to significantly change the structure and properties of carbon membrane. FTIR results concluded that the carbon yield still could be increased by pyrolyzing PAN membranes at temperature higher than 800oC since the existence of other functional group instead of CH group. Gas adsorption analysis showed that the average pore diameter increased up to 800oC.

  7. Adsorption dynamics of copper ion by low cost activated carbon

    International Nuclear Information System (INIS)

    Arivoli, S.; Saravanan, S.; Nandhakumar, V.; Nagarajan, Sulochana

    2009-01-01

    The activated carbon was prepared using solid waste called Terminalia Catappa Linn shell and the physicochemical properties of carbon were investigated to explore the adsorption process. The effectiveness of such carbon in adsorbing copper ion from aqueous solution has been studied as a function of agitation time, adsorbent dosage, initial metal ion concentration, temperature, pH, and desorption. Adsorption equilibrium studies were carried out in order to optimize the experimental conditions. The adsorption of copper ion onto carbon followed a first order kinetic model. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity Qm was 30.60, 33.85, 35.87, and 38.35 at initial PH 7.0. The equilibrium time was found to be 40 min for all initial concentrations studied. Desorption studies were performed with dilute HCl and show that ion exchange is the predominant copper ion adsorption mechanism. The adsorbent was found to be both effective and economically viable. (author)

  8. Adsorptivity of uranium by aluminium-activated carbon composite adsorbent

    International Nuclear Information System (INIS)

    Katoh, Shunsaku; Sugasaka, Kazuhiko; Fujii, Ayako; Takagi, Norio; Miyai, Yoshitaka

    1976-01-01

    To research the adsorption process of uranium from sea water by aluminium-activated carbon composite adsorbent (C-Al-OH), the authors examined the effects of temperature, pH and carbonate ion concentration of the solution upon the adsorption of uranium, using sodium chloride solution and natural sea water. The continued mixing of the solution for the duration of two to four hours was required to attain the apparent equilibrium of adsorption. The adsorption velocity at an early stage and the uptake of uranium at the final stage showed an increase in proportion to a rise in the adsorption temperature. In the experiment of adsorption for which sodium chloride solution was used, the linear relationship between the logarithm of the distribution coefficient (K sub(d)) and the pH of the solution was recognized. The uptake of the uranium from the solution at the pH of 12 increased as the carbonate ion concentration in the solution decreased. The uranyl ion in the natural sea water was assumed to be uranyl carbonate complex ion (UO 2 (CO 3 ) 3 4- ). As the result of the calculation conducted by using the formation constants for uranyl complexes in literature, it was found that uranyl hydroxo complex ion (UO 2 (OH) 3 - ) increased in line with a decrease of the carbonate ion concentration in the solution. The above results of the experiment suggested that the adsorption of uranium by the adsorbent (C-Al-OH) was cationic adsorption or hydrolysis adsorption being related with the active proton on the surface of the adsorbent. (auth.)

  9. Tc-99 Adsorption on Selected Activated Carbons - Batch Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Wellman, Dawn M.; Golovich, Elizabeth C.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    CH2M HILL Plateau Remediation Company (CHPRC) is currently developing a 200-West Area groundwater pump-and-treat system as the remedial action selected under the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision for Operable Unit (OU) 200-ZP-1. This report documents the results of treatability tests Pacific Northwest National Laboratory researchers conducted to quantify the ability of selected activated carbon products (or carbons) to adsorb technetium-99 (Tc-99) from 200-West Area groundwater. The Tc-99 adsorption performance of seven activated carbons (J177601 Calgon Fitrasorb 400, J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, J177612 Norit GAC830, J177613 Norit GAC830, and J177617 Nucon LW1230) were evaluated using water from well 299-W19-36. Four of the best performing carbons (J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, and J177613 Norit GAC830) were selected for batch isotherm testing. The batch isotherm tests on four of the selected carbons indicated that under lower nitrate concentration conditions (382 mg/L), Kd values ranged from 6,000 to 20,000 mL/g. In comparison. Under higher nitrate (750 mg/L) conditions, there was a measureable decrease in Tc-99 adsorption with Kd values ranging from 3,000 to 7,000 mL/g. The adsorption data fit both the Langmuir and the Freundlich equations. Supplemental tests were conducted using the two carbons that demonstrated the highest adsorption capacity to resolve the issue of the best fit isotherm. These tests indicated that Langmuir isotherms provided the best fit for Tc-99 adsorption under low nitrate concentration conditions. At the design basis concentration of Tc 0.865 µg/L(14,700 pCi/L), the predicted Kd values from using Langmuir isotherm constants were 5,980 mL/g and 6,870 mL/g for for the two carbons. These Kd values did not meet the target Kd value of 9,000 mL/g. Tests

  10. Breakthrough CO₂ adsorption in bio-based activated carbons.

    Science.gov (United States)

    Shahkarami, Sepideh; Azargohar, Ramin; Dalai, Ajay K; Soltan, Jafar

    2015-08-01

    In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide (KOH) activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25-65°C and inlet CO2 concentration range of 10-30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273 K, respectively. Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm(3)/g and surface area of 1400 m(2)/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after 50 cycles with low temperature (160°C) regeneration. Copyright © 2015. Published by Elsevier B.V.

  11. Nickel adsorption by sodium polyacrylate-grafted activated carbon

    International Nuclear Information System (INIS)

    Ewecharoen, A.; Thiravetyan, P.; Wendel, E.; Bertagnolli, H.

    2009-01-01

    A novel sodium polyacrylate grafted activated carbon was produced by using gamma radiation to increase the number of functional groups on the surface. After irradiation the capacity for nickel adsorption was studied and found to have increased from 44.1 to 55.7 mg g -1 . X-ray absorption spectroscopy showed that the adsorbed nickel on activated carbon and irradiation-grafted activated carbon was coordinated with 6 oxygen atoms at 2.04-2.06 A. It is proposed that this grafting technique could be applied to other adsorbents to increase the efficiency of metal adsorption.

  12. Relationship between carbon microstructure, adsorption energy and hydrogen adsorption capacity at different temperatures

    International Nuclear Information System (INIS)

    Jagiello, J.; Thommes, M.

    2005-01-01

    Various microporous materials such as activated carbons, nano-tubes, synthetic micro-porous carbons as well as metal organic framework materials are being considered for hydrogen storage applications by means of physical adsorption. To develop materials of practical significance for hydrogen storage it is important to understand the relationships between pore sizes, adsorption energies and adsorption capacities. The pore size distribution (PSD) characterization is traditionally obtained from the analysis of nitrogen adsorption isotherms measured at 77 K. However, a portion of the pores accessible to H 2 may not be accessible to N 2 at this temperature. Therefore, it was recently proposed to use the DFT analysis of H 2 adsorption isotherms to characterize pore structure of materials considered for hydrogen storage applications [1]. In present work, adsorption isotherms of H 2 and N 2 at cryogenic temperatures are used for the characterization of carbon materials. Adsorption measurements were performed with Autosorb 1 MP [Quantachrome Instruments, Boynton Beach, Florida, USA]. As an example, Fig 1 compares PSDs calculated for the activated carbon sample (F400, Calgon Carbon) using combined H 2 and N 2 data, and using N 2 isotherm only. The nitrogen derived PSD does not include certain amount of micro-pores which are accessible to H 2 but not to N 2 molecules. Obviously, the difference in the calculated PSDs by the two methods will depend on the actual content of small micro-pores in a given sample. Carbon adsorption properties can also be characterized by the isosteric heat of adsorption, Qst, related to the adsorption energy and dependent on the carbon pore/surface structure. Fig 2 shows Qst data calculated using the Clausius-Clapeyron equation from H 2 isotherms measured at 77 K and 87 K for the carbon molecular sieve CMS 5A (Takeda), oxidized single wall nano-tubes (SWNT) [2], and graphitized carbon black (Supelco). The Qst values decrease with increasing pore

  13. Hydrogen adsorption in the series of carbon nanostructures: Graphenes-graphene nanotubes-nanocrystallites

    Science.gov (United States)

    Soldatov, A. P.; Kirichenko, A. N.; Tat'yanin, E. V.

    2016-07-01

    A comparative analysis of hydrogen absorption capability is performed for the first time for three types of carbon nanostructures: graphenes, oriented carbon nanotubes with graphene walls (OCNTGs), and pyrocarbon nanocrystallites (PCNs) synthesized in the pores of TRUMEM ultrafiltration membranes with mean diameters ( D m) of 50 and 90 nm, using methane as the pyrolized gas. The morphology of the carbon nanostructures is studied by means of powder X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM). Hydrogen adsorption is investigated via thermogravimetric analysis (TGA) in combination with mass-spectrometry. It is shown that only OCNTGs can adsorb and store hydrogen, the desorption of which under atmospheric pressure occurs at a temperature of around 175°C. Hydrogen adsorption by OCNTGs is quantitatively determined and found to be about 1.5% of their mass. Applying certain assumptions, the relationship between the mass of carbon required for the formation of single-wall OCNTGs in membrane pores and the surface area of pores is established. Numerical factor Ψ = m dep/ m calc, where m dep is the actual mass of carbon deposited upon the formation of OCNTGs and mcalc is the calculated mass of carbon necessary for the formation of OCNTGs is introduced. It is found that the dependence of specific hydrogen adsorption on the magnitude of the factor has a maximum at Ψ = 1.2, and OCNTGs can adsorb and store hydrogen in the interval 0.4 to 0.6 hydrogen adsorption and its relationship to the structure of carbon nanoformations are examined.

  14. Study of adsorption properties on lithium doped activated carbon materials

    International Nuclear Information System (INIS)

    Los, S.; Daclaux, L.; Letellier, M.; Azais, P.

    2005-01-01

    A volumetric method was applied to study an adsorption coefficient of hydrogen molecules in a gas phase on super activated carbon surface. The investigations were focused on getting the best possible materials for the energy storage. Several treatments on raw samples were used to improve adsorption properties. The biggest capacities were obtain after high temperature treatment at reduced atmosphere. The adsorption coefficient at 77 K and 2 MPa amounts to 3.158 wt.%. The charge transfer between lithium and carbon surface groups via the doping reaction enhanced the energy of adsorption. It was also found that is a gradual decrease in the adsorbed amount of H 2 molecules due to occupation active sites by lithium ions. (author)

  15. Water and Carbon Dioxide Adsorption at Olivine Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kerisit, Sebastien N.; Bylaska, Eric J.; Felmy, Andrew R.

    2013-11-14

    Plane-wave density functional theory (DFT) calculations were performed to simulate water and carbon dioxide adsorption at the (010) surface of five olivine minerals, namely, forsterite (Mg2SiO4), calcio-olivine (Ca2SiO4), tephroite (Mn2SiO4), fayalite (Fe2SiO4), and Co-olivine (Co2SiO4). Adsorption energies per water molecule obtained from energy minimizations varied from -78 kJ mol-1 for fayalite to -128 kJ mol-1 for calcio-olivine at sub-monolayer coverage and became less exothermic as coverage increased. In contrast, carbon dioxide adsorption energies at sub-monolayer coverage ranged from -20 kJ mol-1 for fayalite to -59 kJ mol-1 for calcio-olivine. Therefore, the DFT calculations show a strong driving force for carbon dioxide displacement by water at the surface of all olivine minerals in a competitive adsorption scenario. Additionally, adsorption energies for both water and carbon dioxide were found to be more exothermic for the alkaline-earth (AE) olivines than for the transition-metal (TM) olivines and to not correlate with the solvation enthalpies of the corresponding divalent cations. However, a correlation was obtained with the charge of the surface divalent cation indicating that the more ionic character of the AE cations in the olivine structure relative to the TM cations leads to greater interactions with adsorbed water and carbon dioxide molecules at the surface and thus more exothermic adsorption energies for the AE olivines. For calcio-olivine, which exhibits the highest divalent cation charge of the five olivines, ab initio molecular dynamics simulations showed that this effect leads both water and carbon dioxide to react with the surface and form hydroxyl groups and a carbonate-like species, respectively.

  16. Hydrogen adsorption in carbon nanostructures compared

    NARCIS (Netherlands)

    Schimmel, H.G.; Nijkamp, M.G.; Kearley, G.J.; Rivera, A.; de Jong, K.P.; Mulder, F.M.

    2004-01-01

    Recent reports continue to suggest high hydrogen storage capacities for some carbon nanostructures due to a stronger interaction between hydrogen and carbon. Here the interaction of hydrogen with activated charcoal, carbon nanofibers, single walled carbon nanotubes (SWNT), and electron beam ‘opened’

  17. Hierarchically structured, nitrogen-doped carbon membranes

    KAUST Repository

    Wang, Hong

    2017-08-03

    The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced on a large-scale approach. The unique HNDCM holds great promise as components in separation and advanced carbon devices because they could offer unconventional fluidic transport phenomena on the nanoscale. Overall, the invention set forth herein covers a hierarchically structured, nitrogen-doped carbon membranes and methods of making and using such a membranes.

  18. Removal of bisphenol A by adsorption mechanism using PES-SiO2 composite membranes.

    Science.gov (United States)

    Muhamad, Mimi Suliza; Salim, Mohd Razman; Lau, Woei Jye; Hadibarata, Tony; Yusop, Zulkifli

    2016-08-01

    Polyethersulphone (PES) membranes blended with silicon dioxide (SiO2) nanoparticles were prepared via a dry-jet wet spinning technique for the removal of bisphenol A (BPA) by adsorption mechanism. The morphology of SiO2 nanoparticles was analysed using a transmission electron microscopy and particle size distribution was also analysed. The prepared membranes were characterized by several techniques including field emission scanning electron microscopy, Fourier transform infrared spectroscopy and water contact angle. The adsorption mechanism of membrane towards BPA was evaluated by batch experiments and kinetic model. The influence of natural organic matter (NOM) in feed water on membrane BPA removal was also studied by filtration experiments. Results showed that BPA adsorption capacity as high as 53 µg/g could be achieved by the PES membrane incorporated with 2 wt% SiO2 in which the adsorption mechanism was in accordance with the pseudo-second-order kinetic model. The intraparticles diffusion model suggested that the rate limiting factor of membrane adsorption mechanism is governed by the diffusion of BPA into the membrane pores. The presence of 10 ppm NOM has reported to negatively reduce BPA removal by 24%, as it tended to compete with BPA for membrane adsorption. This work has demonstrated that PES-SiO2 membrane has the potential to eliminate trace amount of BPA from water source containing NOM.

  19. Carbon membranes - current progress and future prospects

    International Nuclear Information System (INIS)

    Tennison, St.; Arnott, K.; Richter, H.

    2007-01-01

    The future use of nano-porous gas separation membranes will be dependent on significant reductions in the membrane and module costs, improvements in production methods to allow better reproducibility, ability to scale up production and improved performance and understanding of the mode of operation of the membrane systems. New approaches to ceramic supported carbon membranes could offer solutions to these problems. Whilst the performance characteristics underline the limitations of these membranes they also show where specific process opportunities might be accessible particularly in environmental and high temperature separations. (authors)

  20. Comparative evaluation of adsorption kinetics of diclofenac and isoproturon by activated carbon.

    Science.gov (United States)

    Torrellas, Silvia A; Rodriguez, Araceli R; Escudero, Gabriel O; Martín, José María G; Rodriguez, Juan G

    2015-01-01

    Adsorption mechanism of diclofenac and isoproturon onto activated carbon has been proposed using Langmuir and Freundlich isotherms. Adsorption capacity and optimum adsorption isotherms were predicted by nonlinear regression method. Different kinetic equations, pseudo-first-order, pseudo-second-order, intraparticle diffusion model and Bangham kinetic model, were applied to study the adsorption kinetics of emerging contaminants on activated carbon in two aqueous matrices.

  1. Adsorption Properties of Lignin-derived Activated Carbon Fibers (LACF)

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gallego, Nidia C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Thibaud-Erkey, Catherine [United Technologies Research Center (UTRC), East Hartford, CT (United States); Karra, Reddy [United Technologies Research Center (UTRC), East Hartford, CT (United States)

    2016-04-01

    The object of this CRADA project between Oak Ridge National Laboratory (ORNL) and United Technologies Research Center (UTRC) is the characterization of lignin-derived activated carbon fibers (LACF) and determination of their adsorption properties for volatile organic compounds (VOC). Carbon fibers from lignin raw materials were manufactured at Oak Ridge National Laboratory (ORNL) using the technology previously developed at ORNL. These fibers were physically activated at ORNL using various activation conditions, and their surface area and pore-size distribution were characterized by gas adsorption. Based on these properties, ORNL did down-select five differently activated LACF materials that were delivered to UTRC for measurement of VOC adsorption properties. UTRC used standard techniques based on breakthrough curves to measure and determine the adsorption properties of indoor air pollutants (IAP) - namely formaldehyde and carbon dioxide - and to verify the extent of saturated fiber regenerability by thermal treatments. The results are summarized as follows: (1) ORNL demonstrated that physical activation of lignin-derived carbon fibers can be tailored to obtain LACF with surface areas and pore size distributions matching the properties of activated carbon fibers obtained from more expensive, fossil-fuel precursors; (2) UTRC investigated the LACF potential for use in air cleaning applications currently pursued by UTRC, such as building ventilation, and demonstrated their regenerability for CO2 and formaldehyde, (3) Both partners agree that LACF have potential for possible use in air cleaning applications.

  2. Characterizing adsorption of associating surfactants on carbonates surfaces.

    Science.gov (United States)

    Jian, Guoqing; Puerto, Maura; Wehowsky, Anna; Miller, Clarence; Hirasaki, George J; Biswal, Sibani L

    2018-03-01

    The adsorption of anionic surfactants onto positively charged carbonate minerals is typically high due to electrostatic interactions. By blending anionic surfactants with cationic or zwitterionic surfactants, which naturally form surfactant complexes, surfactant adsorption is expected to be influenced by a competition between surfactant complexes and surfactant-surface interactions. The adsorption behavior of surfactant blends known to form complexes was investigated. The surfactants probed include an anionic C 15-18 internal olefin sulfonate (IOS), a zwitterionic lauryl betaine (LB), and an anionic C 13 -alcohol polyethylene glycol ether carboxylic acid (L38). An analytical method based on high-performance liquid chromatography evaporative light scattering detector (HPLC-ELSD) was developed to measure three individual surfactant concentrations from a blended surfactant solution. The adsorption of the individual surfactants and surfactant blends were systematically investigated on different mineral surfaces using varying brine solutions. LB adsorption on calcite surfaces was found to be significantly increased when blended with IOS or L38 since it forms surfactant complexes that partition to the surface. However, the total adsorption of the LB-IOS-L38 solution on dolomite decreased from 3.09 mg/m 2 to 1.97 mg/m 2 when blended together compared to summing the adsorption values of individual surfactants, which highlights the importance of mixed surfactant association. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Modeling of CO2 Adsorption on Activated Carbon and 13X Zeolite via Vacuum Swing Adsorption

    Science.gov (United States)

    Zarghampoor, M. H.; Mozaffarian, M.; Soleimani, M.; Takht Ravanchi, M.

    2017-06-01

    Due to carbon dioxide role in global warming, low CO2 emission limits have been established in recent years. This has led to a variety of studies on CO2 removal approaches. In this study, a VSA cycle consisting of two packed beds is considered for CO2 removal from flue gas. An atmospheric stream containing 20 CO2 and 80 N2 is fed to the beds at 50°C. Two adsorbents, namely Zeolite 13X and activated carbon were selected to compare their performance. Due to the monolayer adsorption of CO2 and N2 on these adsorbents, the Toth isotherm was used for equilibrium adsorption estimation. A quasi-second order model was considered for the mass transfer rate prediction due to low CO2 concentration. The modeling results showed that the average absolute deviation for equilibrium adsorption capacity prediction was 2, and the CO2 breakthrough time curve was predicted with less than 2.5 deviation. Based on the results, the VSA cycle time for zeolite 13X bed will be 3.5 times of the activated carbon bed. Another advantage of Zeolite 13X is that in each process cycle, 80 of adsorbent will be used, while only 74 of activated carbon in beds is used. The advantage of activated carbon bed is its better regeneration capability, since the activated carbon will be regenerated 5 more than zeolite 13X at a vacuum pressure of 0.02bar.

  4. Improved Isotherm Data for Adsorption of Methane on Activated Carbons

    KAUST Repository

    Loh, Wai Soong

    2010-08-12

    This article presents the adsorption isotherms of methane onto two different types of activated carbons, namely, Maxsorb III and ACF (A-20) at temperatures from (5 to 75) °C and pressures up to 2.5 MPa. The volumetric technique has been employed to measure the adsorption isotherms. The experimental results presented herein demonstrate the improved accuracy of the uptake values compared with previous measurement techniques for similar adsorbate-adsorbent combinations. The results are analyzed with various adsorption isotherm models. The heat of adsorption, which is concentration and temperature dependent, has been calculated from the measured isotherm data. Henry\\'s law coefficients for these adsorbent-methane pairs are also evaluated at various temperatures. © 2010 American Chemical Society.

  5. Supported mesoporous carbon ultrafiltration membrane and process for making the same

    Science.gov (United States)

    Strano, Michael; Foley, Henry C.; Agarwal, Hans

    2004-04-13

    A novel supported mesoporous carbon ultrafiltration membrane and process for producing the same. The membranes comprise a mesoporous carbon layer that exists both within and external to the porous support. A liquid polymer precursor composition comprising both carbonizing and noncarbonizing templating polymers is deposited on the porous metal support. The coated support is then heated in an inert-gas atmosphere to pyrolyze the polymeric precursor and form a mesoporous carbon layer on and within the support. The pore-size of the membranes is dependent on the molecular weight of the noncarbonizing templating polymer precursor. The mesoporous carbon layer is stable and can withstand high temperatures and exposure to organic chemicals. Additionally, the porous metal support provides excellent strength properties. The composite structure of the membrane provides novel structural properties and allows for increased operating pressures allowing for greater membrane flow rates. The invention also relates to the use of the novel ultrafiltration membrane to separate macromolecules from solution. An example is shown separating bovine serum albumin from water. The membrane functions by separating and by selective adsorption. Because of the membrane's porous metal support, it is well suited to industrial applications. The unique properties of the supported mesoporous carbon membrane also allow the membrane to be used in transient pressure or temperature swing separations processes. Such processes were not previously possible with existing mesoporous membranes. The present invention, however, possesses the requisite physical properties to perform such novel ultrafiltration processes.

  6. Adsorption of carbon-14 on mortar

    International Nuclear Information System (INIS)

    Matsumoto, Junko; Banba, Tsunetaka; Muraoka, Susumu

    1995-01-01

    The sorption experiments of carbon-14 on the mortar grain (grain size: 0.50--1.0 mm) focused on the chemical form of the carbon-14 were carried out by the batch method. Three kinds of carbon-14 chemical form were used for the experiments: sodium carbonate (Na 2 14 CO 3 ) as the inorganic radiocarbon, and sodium acetate (CH 3 14 COONa) and acetaldehyde ( 14 CH 3 14 CHO) as the organic radiocarbons. 0.30 gram samples of mortar were soaked in the solution with carbon-14 at 15 C for periods of up to 160 days. At the end of each run, carbon-14 concentrations in the supernatants were determined before and after centrifugation (3,500 rpm., 1 hr). In the mortar-sodium carbonate system, the retention process of carbon-14 related to reaction on the surface of the mortar was speculated as follows. First, 3CaO-SiO 2 and 2CaO-SiO 2 of the mortar components contact with water and produce Ca(OH) 2 . Ca(OH) 2 produces Ca 2+ and OH - in the solution. Then, calcite forms from Ca 2+ and CO 3 2- in the solution. Thus, the sorption ratio of carbon-14 onto mortar will be high until mortar has been completely carbonated because Ca 2+ is rich in the mortar and the solubility of calcite is low. In the mortar-organic carbon system, the soluble organic carbon-14 is hardly sorbed on the surface of the mortar. Therefore, the cementitious materials may not inhibit the release of organic radiocarbons from the low-level radioactive wastes, contrary to the case of inorganic radiocarbon

  7. Adsorption of multimeric T cell antigens on carbon nanotubes

    DEFF Research Database (Denmark)

    Fadel, Tarek R; Li, Nan; Shah, Smith

    2013-01-01

    Antigen-specific activation of cytotoxic T cells can be enhanced up to three-fold more than soluble controls when using functionalized bundled carbon nanotube substrates ((b) CNTs). To overcome the denaturing effects of direct adsorption on (b) CNTs, a simple but robust method is demonstrated...... to stabilize the T cell stimulus on carbon nanotube substrates through non-covalent attachment of the linker neutravidin....

  8. Hydrogen adsorption on N-decorated single wall carbon nanotubes

    International Nuclear Information System (INIS)

    Rangel, Eduardo; Ruiz-Chavarria, Gregorio; Magana, L.F.; Arellano, J.S.

    2009-01-01

    Using density functional theory and molecular dynamics we found that N-decorated single walled (8,0) carbon nanotubes are potential high capacity hydrogen storage media. This system could store up to 6.0 wt% hydrogen at 300 K and ambient pressure, with average adsorption energy of -80 meV/(H 2 ). Nitrogen coverage was C 8 N.

  9. Adsorption studies of phosphate ions on alginate-calcium carbonate ...

    African Journals Online (AJOL)

    Alginate-calcium carbonate composite beads was prepared by the sol-gel method and characterized by Fourier transform infra-red spectroscopy (FT-IR) and scanning electron microscope (SEM) instruments. Adsorption potential of phosphate ions have been studied on laboratory scale. The effects of contact time, adsorbent ...

  10. Adsorptive Removal of Malachite Green with Activated Carbon ...

    African Journals Online (AJOL)

    The adsorptive potential of activated carbon prepared by chemical activation from oil palm fruit fibre (OPFAC) to remove malachite green (MG) dye from its aqueous solution was investigated in this study. The OPFAC prepared was characterized by means of BET, TGA, FTIR, pHpzc, elemental analysis and Boehm titration.

  11. ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID

    Science.gov (United States)

    The paper gives results of a study of the adsorption of elemental mercury at 125 C by a sulfuric-acid (H2S04, 50% w/w/ solution)-treated carbon for the removal of mercury from flue gas. The pore structure of the sample was characterized by nitrogen (N2) at -196 C and the t-plot m...

  12. Study of adsorption of Neon on open Carbon nanohorns aggregates

    Science.gov (United States)

    Ziegler, Carl Andrew

    Adsorption isotherms can be used to determine surface area of a substrate and the heat released when adsorption occurs. Our measurements are done determining the equilibrium pressures corresponding to a given amount of gas adsorbed on a substrate at constant temperature. The adsorption studies were done on aggregates of open dahlia-like carbon nanohorns. The nanohorns were oxidized for 9 hours at 550 °C to open them up and render their interior space accessible for adsorption. Volumetric adsorption measurements of Ne were performed at twelve different temperatures between 19 K and 48 K. The isotherms showed two substeps. The first substep corresponds to adsorption on the high energy binding sites in the interior of the nanohorns, near the tip. The second substep corresponds to low energy binding sites both on the outside of the nanotubes and inside the nanotube away from the tip. The isosteric heat measurements obtained from the isotherm data also shows these two distinct substeps. The effective surface area of the open nanotubes was determined from the isotherms using the point-B method. The isosteric heat and surface area data for neon on open nanohorns were compared to two similar experiments of neon adsorbed on aggregates of closed nanohorns.

  13. Influence of resorcinol chemical oxidation on the removal of resulting organic carbon by activated carbon adsorption.

    Science.gov (United States)

    Rodríguez, Eva; Encinas, Angel; Masa, Francisco J; Beltrán, Fernando J

    2008-02-01

    Activated carbon adsorption and chemical oxidation followed by activated carbon adsorption of resorcinol in water has been studied. Three chemical oxidants have been used: hypochlorite, permanganate and Fenton's reagent. The influence of concentrations of resorcinol and activated carbon on adsorption removal rates has been investigated. Both isotherm and adsorption kinetics have been studied. Results are fit well by Freundlich isotherms and adsorption rates of resorcinol were found to follow a pseudo-second-order kinetic model. However, pyrogallol, an intermediate of resorcinol oxidation with permanganate and Fenton's reagent, showed an unfavourable isotherm type. At the conditions investigated, chemical oxidation allows slight reductions of TOC and intermediates formed were found to inhibit the adsorption rate of TOC in the case of permanganate and Fenton's reagent oxidation, likely due to formation of some polymer pyrogallol product. The adsorption process was found to be controlled by pore internal diffusion, which justifies the poor affinity of oxidation intermediates toward activated carbon since molecules of larger size should diffuse rapidly for the adsorption to be effective.

  14. Adsorption of Ammonia on Regenerable Carbon Sorbents

    Science.gov (United States)

    Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

  15. A Review on Adsorption of Cationic Dyes using Activated Carbon

    Directory of Open Access Journals (Sweden)

    Corda Nikita Chrishel

    2018-01-01

    Full Text Available In this article efficiency of activated carbon as a potent adsorbent of cationic dyes has been reviewed. Non-biodegradable nature of pollutants and their removal in the present generation is a great challenge. Therefore, extensive study on adsorption of these classes of pollutants from water bodies is being carried out. Methylene blue (majorly a dye seen in the effluent streams of textile, printing, paper industries along with some of the commonly used cationic dyes in process industries and their sorption on activated carbon are reviewed here. High cost of commercially activated carbon which is a limitation to its extensive use have paved way for study of adsorption by naturally obtained and extracted activated carbon from agricultural wastes and various other sources. The purpose of this review paper is to summarize the available information on the removal of cationic dyes using naturally extracted and commercially obtained activated carbon. Various parameters such as temperature, initial dye concentration, pH, contact time, adsorbent dosage, particle size, stirring, agitation etc. were studied and the optimum parameters were determined based on the experimental outcomes. Equilibrium data was examined using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich and few other isotherm models. Kinetic studies also have been carried out to find the most suitable way of expressing the adsorption process.

  16. Irreversible adsorption of phenolic compounds by activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Grant, T.M.; King, C.J.

    1988-12-01

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs.

  17. Irreversible adsorption of phenolic compounds by activated carbons

    International Nuclear Information System (INIS)

    Grant, T.M.; King, C.J.

    1988-12-01

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs

  18. Neon adsorption on oxidized single-walled carbon nanohorns

    Science.gov (United States)

    Krungleviciute, Vaiva; Migone, Aldo; Yudasaka, Masako; Iijima, Sumio

    2012-02-01

    We will present the results of a study of neon adsorption on oxidized single-walled carbon nanohorns. Our adsorption isotherm measurements were conducted at temperatures below 24.5 K, the triple point for Ne. Results for the effective specific surface area and for the effective pore volume of the nanohorn aggregates will be presented. We will also report on the sorbent-loading dependence of the isosteric heat of neon on the nanohorns, and on the binding energy. Our results for this system will be compared with those obtained for Ne on a sample of dahlia-like nanohorns annealed at 520 K.

  19. Novel Aluminum Oxide-Impregnated Carbon Nanotube Membrane for the Removal of Cadmium from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Ihsanullah

    2017-09-01

    Full Text Available An aluminum oxide-impregnated carbon nanotube (CNT-Al2O3 membrane was developed via a novel approach and used in the removal of toxic metal cadmium ions, Cd(II. The membrane did not require any binder to hold the carbon nanotubes (CNTs together. Instead, the Al2O3 particles impregnated on the surface of the CNTs were sintered together during heating at 1400 °C. Impregnated CNTs were characterized using XRD, while the CNT-Al2O3 membrane was characterized using scanning electron microscopy (SEM. Water flux, contact angle, and porosity measurements were performed on the membrane prior to the Cd(II ion removal experiment, which was conducted in a specially devised continuous filtration system. The results demonstrated the extreme hydrophilic behavior of the developed membrane, which yielded a high water flux through the membrane. The filtration system removed 84% of the Cd(II ions at pH 7 using CNT membrane with 10% Al2O3 loading. A maximum adsorption capacity of 54 mg/g was predicted by the Langmuir isotherm model for the CNT membrane with 10% Al2O3 loading. This high adsorption capacity indicated that adsorption was the main mechanism involved in the removal of Cd(II ions.

  20. Synthesis of Carbon Nanotube (CNT Composite Membranes

    Directory of Open Access Journals (Sweden)

    Dusan Losic

    2010-12-01

    Full Text Available Carbon nanotubes are attractive approach for designing of new membranes for advanced molecular separation because of their unique transport properties and ability to mimic biological protein channels. In this work the synthetic approach for fabrication of carbon nanotubes (CNTs composite membranes is presented. The method is based on growth of multi walled carbon nanotubes (MWCNT using chemical vapour deposition (CVD on the template of nanoporous alumina (PA membranes. The influence of experimental conditions including carbon precursor, temperature, deposition time, and PA template on CNT growth process and quality of fabricated membranes was investigated. The synthesis of CNT/PA composites with controllable nanotube dimensions such as diameters (30–150 nm, and thickness (5–100 µm, was demonstrated. The chemical composition and morphological characteristics of fabricated CNT/PA composite membranes were investigated by various characterisation techniques including scanning electron microscopy (SEM, energy-dispersive x-ray spectroscopy (EDXS, high resolution transmission electron microscopy (HRTEM and x-ray diffraction (XRD. Transport properties of prepared membranes were explored by diffusion of dye (Rose Bengal used as model of hydrophilic transport molecule.

  1. Self-assembled ordered carbon-nanotube arrays and membranes.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Siegal, Michael P.; Yelton, William Graham

    2004-11-01

    Imagine free-standing flexible membranes with highly-aligned arrays of carbon nanotubes (CNTs) running through their thickness. Perhaps with both ends of the CNTs open for highly controlled nanofiltration? Or CNTs at heights uniformly above a polymer membrane for a flexible array of nanoelectrodes or field-emitters? How about CNT films with incredible amounts of accessible surface area for analyte adsorption? These self-assembled crystalline nanotubes consist of multiple layers of graphene sheets rolled into concentric cylinders. Tube diameters (3-300 nm), inner-bore diameters (2-15 nm), and lengths (nanometers - microns) are controlled to tailor physical, mechanical, and chemical properties. We proposed to explore growth and characterize nanotube arrays to help determine their exciting functionality for Sandia applications. Thermal chemical vapor deposition growth in a furnace nucleates from a metal catalyst. Ordered arrays grow using templates from self-assembled hexagonal arrays of nanopores in anodized-aluminum oxide. Polymeric-binders can mechanically hold the CNTs in place for polishing, lift-off, and membrane formation. The stiffness, electrical and thermal conductivities of CNTs make them ideally suited for a wide-variety of possible applications. Large-area, highly-accessible gas-adsorbing carbon surfaces, superb cold-cathode field-emission, and unique nanoscale geometries can lead to advanced microsensors using analyte adsorption, arrays of functionalized nanoelectrodes for enhanced electrochemical detection of biological/explosive compounds, or mass-ionizers for gas-phase detection. Materials studies involving membrane formation may lead to exciting breakthroughs in nanofiltration/nanochromatography for the separation of chemical and biological agents. With controlled nanofilter sizes, ultrafiltration will be viable to separate and preconcentrate viruses and many strains of bacteria for 'down-stream' analysis.

  2. Modeling equilibrium adsorption of organic micropollutants onto activated carbon

    KAUST Repository

    De Ridder, David J.

    2010-05-01

    Solute hydrophobicity, polarizability, aromaticity and the presence of H-bond donor/acceptor groups have been identified as important solute properties that affect the adsorption on activated carbon. However, the adsorption mechanisms related to these properties occur in parallel, and their respective dominance depends on the solute properties as well as carbon characteristics. In this paper, a model based on multivariate linear regression is described that was developed to predict equilibrium carbon loading on a specific activated carbon (F400) for solutes reflecting a wide range of solute properties. In order to improve prediction accuracy, groups (bins) of solutes with similar solute properties were defined and solute removals were predicted for each bin separately. With these individual linear models, coefficients of determination (R2) values ranging from 0.61 to 0.84 were obtained. With the mechanistic approach used in developing this predictive model, a strong relation with adsorption mechanisms is established, improving the interpretation and, ultimately, acceptance of the model. © 2010 Elsevier Ltd.

  3. Removal of Congo Red from Aqueous Solution by Anion Exchange Membrane (EBTAC): Adsorption Kinetics and Themodynamics

    Science.gov (United States)

    Khan, Muhammad Imran; Akhtar, Shahbaz; Zafar, Shagufta; Shaheen, Aqeela; Khan, Muhammad Ali; Luque, Rafael; ur Rehman, Aziz

    2015-01-01

    The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as Bangham and modified freundlich Equations, were employed to evaluate the experimental results. Parameters such as adsorption capacities, rate constant and related correlation coefficients for every model were calculated and discussed. The adsorption of CR on anion exchange membranes followed pseudo-second-order Kinetics. Thermodynamic parameters, namely changes in Gibbs free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) were calculated for the adsorption of congo red, indicating an exothermic process. PMID:28793430

  4. Removal of Congo Red from Aqueous Solution by Anion Exchange Membrane (EBTAC): Adsorption Kinetics and Themodynamics.

    Science.gov (United States)

    Khan, Muhammad Imran; Akhtar, Shahbaz; Zafar, Shagufta; Shaheen, Aqeela; Khan, Muhammad Ali; Luque, Rafael; Rehman, Aziz Ur

    2015-07-08

    The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as Bangham and modified freundlich Equations, were employed to evaluate the experimental results. Parameters such as adsorption capacities, rate constant and related correlation coefficients for every model were calculated and discussed. The adsorption of CR on anion exchange membranes followed pseudo-second-order Kinetics. Thermodynamic parameters, namely changes in Gibbs free energy ( ∆G° ), enthalpy ( ∆H° ) and entropy ( ∆S° ) were calculated for the adsorption of congo red, indicating an exothermic process.

  5. [Adsorption kinetics and mechanism of lead (II) on polyamine-functionalized mesoporous activated carbon].

    Science.gov (United States)

    Li, Kun-Quan; Wang, Yan-Jin; Yang, Mei-Rong; Zhu, Zhi-Qiang; Zheng, Zheng

    2014-08-01

    Bagasse mesoporous carbon was prepared by microwave assisted H3 PO4 activation. Amido and imido groups were modified with ethanediamine on the channels' surface of mesoporous carbon through nitric oxidation and amide reaction. The influence of Pb(II) concentration, adsorption time on Pb(II) adsorption on the ethanediamine-modified mesoporous carbon (AC-EDA) was investigated. The adsorption kinetics and mechanism were also discussed. The results showed that AC-EDA had a great performance for Pb(II) adsorption, and more than 70% of Pb(II) was adsorbed in 5 minutes. The adsorption amount of Pb(II) on the carbon increased with the increase of solution pH in acidic conditions. It was found that AC-EDA had different binding energies on different adsorption sites for Pb(II) separation. The Pb(II) adsorption process on AC-EDA was controlled by intra-particle diffusion in the first 3 min, and then film diffusion played the important pole on the adsorption. The adsorption amount increased with the increase of temperature, indicating the adsorption was an endothermic reaction. The high adsorption energy (> 11 kJ x mol(-1)) implied that the) adsorption was a chemical adsorption. The XPS of AC-EDA before and after Pb(II) adsorption showed that the polyamine group was involved in the adsorption, and should be a main factor of the high efficient adsorption.

  6. CO2 adsorption using TiO2 composite polymeric membranes: A kinetic study.

    Science.gov (United States)

    Hafeez, Sarah; Fan, X; Hussain, Arshad; Martín, C F

    2015-09-01

    CO2 is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas separation by composite membranes. The separation of CO2 by a membrane is not just a process to physically sieve out of CO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb CO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of CO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of CO2 through membranes. Pure cellulose acetate (CA) and cellulose acetate-titania nanoparticle (CA-TiO2) composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended CA-TiO2 membrane adsorbed more quantity of CO2 gas as compared to pure CA membrane. The high CO2 adsorption capacity may enhance the diffusion and solubility of CO2 in the CA-TiO2 composite membrane, which results in a better CO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion models. According to correlation factor R(2), the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion. Copyright © 2015. Published by Elsevier B.V.

  7. TESTING GUIDELINES FOR TECHNETIUM-99 ADSORPTION ON ACTIVATED CARBON

    International Nuclear Information System (INIS)

    Byrnes, M.E.

    2010-01-01

    CH2M HILL Plateau Remediation Company (CHPRC) is currently evaluating the potential use of activated carbon adsorption for removing technetium-99 from groundwater as a treatment method for the Hanford Site's 200 West Area groundwater pump-and-treat system. The current pump-and-treat system design will include an ion-exchange (IX) system for selective removal of technetium-99 from selected wells prior to subsequent treatment of the water in the central treatment system. The IX resin selected for technetium-99 removal is Purolite A530E. The resin service life is estimated to be approximately 66.85 days at the design technetium-99 loading rate, and the spent resin must be replaced because it cannot be regenerated. The resulting operating costs associated with resin replacement every 66.85 days are estimated at $0.98 million/year. Activated carbon pre-treatment is being evaluated as a potential cost-saving measure to offset the high operating costs associated with frequent IX resin replacement. This document is preceded by the Literature Survey of Technetium-99 Groundwater Pre-Treatment Option Using Granular Activated Carbon (SGW-43928), which identified and evaluated prior research related to technetium-99 adsorption on activated carbon. The survey also evaluated potential operating considerations for this treatment approach for the 200 West Area. The preliminary conclusions of the literature survey are as follows: (1) Activated carbon can be used to selectively remove technetium-99 from contaminated groundwater. (2) Technetium-99 adsorption onto activated carbon is expected to vary significantly based on carbon types and operating conditions. For the treatment approach to be viable at the Hanford Site, activated carbon must be capable of achieving a designated minimum technetium-99 uptake. (3) Certain radionuclides known to be present in 200 West Area groundwater are also likely to adsorb onto activated carbon. (4) Organic solvent contaminants of concern (COCs) will

  8. Langmuir, Freundlich and Temkin Adsorption Isotherms of Propranolol on Multi-Wall Carbon Nanotube

    OpenAIRE

    Mehdi Vadi

    2017-01-01

    We have studied the adsorption of the isotherm of Propranolol, on multi carbon nanotube. The adsorption equilibrium isotherms were fitted by Freundlich, Langmuir, and Temkin models. It was found that the Langmuir model described the adsorption process better than other two isotherm models. The amount of NSAIDs (Propranolol) adsorbed on carbon nanotube surface increased with the increase of the initial NSAIDs concentration.

  9. Enhanced CO2 Adsorption on Activated Carbon Fibers Grafted with Nitrogen-Doped Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yu-Chun Chiang

    2017-05-01

    Full Text Available In this paper, multiscale composites formed by grafting N-doped carbon nanotubes (CNs on the surface of polyamide (PAN-based activated carbon fibers (ACFs were investigated and their adsorption performance for CO2 was determined. The spaghetti-like and randomly oriented CNs were homogeneously grown onto ACFs. The pre-immersion of cobalt(II ions for ACFs made the CNs grow above with a large pore size distribution, decreased the oxidation resistance, and exhibited different predominant N-functionalities after chemical vapor deposition processes. Specifically, the CNs grafted on ACFs with or without pre-immersion of cobalt(II ions were characterized by the pyridine-like structures of six-member rings or pyrrolic/amine moieties, respectively. In addition, the loss of microporosity on the specific surface area and pore volume exceeded the gain from the generation of the defects from CNs. The adsorption capacity of CO2 decreased gradually with increasing temperature, implying that CO2 adsorption was exothermic. The adsorption capacities of CO2 at 25 °C and 1 atm were between 1.53 and 1.92 mmol/g and the Freundlich equation fit the adsorption data well. The isosteric enthalpy of adsorption, implying physical adsorption, indicated that the growth of CNTs on the ACFs benefit CO2 adsorption.

  10. Surface structure and adsorption properties of ultrafine porous carbon fibers

    International Nuclear Information System (INIS)

    Song Xiaofeng; Wang Ce; Zhang Dejiang

    2009-01-01

    Ultrafine porous carbon fibers (UPCFs) were successfully synthesized by chemical activation of electrospun polyacrylonitrile fibers. In the current approach, potassium hydroxide was adopted as activation reagent. UPCFs were systematically evaluated by scanning electron microscope and nitrogen adsorption. The mass ratio of potassium hydroxide to preoxidized fibers, activation temperature and activation time are crucial for producing high quality UPCFs. The relationships between porous structure and process parameters are explored. UPCFs were applied as adsorbent for nitrogen monoxide to be compared with commercial porous carbon fibers.

  11. Adsorption Enthalpies of Hydrogen on Chemically Enhanced Carbon Nanospaces

    Science.gov (United States)

    Gillespie, Andrew; Dohnke, Elmar; Schaeperkoetter, Joseph; Stalla, David; Pfeifer, Peter

    2014-03-01

    Chemical functionalization of carbon nanopore spaces has been shown to significantly increase the differential enthalpy of adsorption of hydrogen (ca. 9kJ/mol). This improved surface interaction corresponds to an increased density of the adsorbed film. Functionalized carbon samples have been produced through KOH activation, deposition of decaborane, and high temperature annealing. Hydrogen sorption measurements have shown significant improvements to stored film densities and binding energies. In this talk, a systematic study of the effect that boron concentration has on the samples' pore structures, binding energies, surface excess concentrations, and volumetric storage capacities is presented. Work supported by DOE-EERE, Award No. DE-FG36-08GO18142.

  12. Carbon nanofibers in catalytic membrane microreactors

    NARCIS (Netherlands)

    Aran, H.C.; Pacheco Benito, Sergio; Luiten-Olieman, Maria W.J.; Er, S.; Wessling, Matthias; Lefferts, Leonardus; Benes, Nieck Edwin; Lammertink, Rob G.H.

    2011-01-01

    In this study, we report on the fabrication and operation of new hybrid membrane microreactors for gas–liquid–solid (G–L–S) reactions. The presented reactors consist of porous stainless steel tubes onto which carbon nanofibers (CNFs) are grown as catalyst support, all encapsulated by a gas permeable

  13. Heavy metal ion adsorption onto polypyrrole-impregnated porous carbon.

    Science.gov (United States)

    Choi, Moonjung; Jang, Jyongsik

    2008-09-01

    Polypyrrole-impregnated porous carbon was readily synthesized using vapor infiltration polymerization of pyrrole monomers. The results show that the functionalized polymer layer was successfully coated onto the pore surface of carbon without collapse of mesoporous structure. The modified porous carbon exhibited an improved complexation affinity for heavy metal ions such as mercury, lead, and silver ions due to the amine group of polypyrrole. The introduced polypyrrole layer could provide the surface modification to be applied for heavy metal ion adsorbents. Especially, polymer-impregnated porous carbon has an enhanced heavy metal ion uptake, which is 20 times higher than that of adsorbents with amine functional groups. Furthermore, the relationship between the coated polymer amount and surface area was also investigated in regard to adsorption capacity.

  14. Hydrogen Adsorption on Activated Carbon an Carbon Nanotubes Using Volumetric Differential Pressure Technique

    International Nuclear Information System (INIS)

    Sanip, S. M.; Saidin, M. A. R.; Aziz, M.; Ismail, A. F.

    2010-01-01

    A simple hydrogen adsorption measurement system utilizing the volumetric differential pressure technique has been designed, fabricated and calibrated. Hydrogen adsorption measurements have been carried out at temperatures 298 K and 77 K on activate carbon and carbon nanotubes with different surface areas. The adsorption data obtained will be helpful in understanding the adsorption property of the studied carbon materials using the fundamentals of adsorption theory. The principle of the system follows the Sievert-type method. The system measures a change in pressure between the reference cell, R1 and the sample cell S1, S2, S3 over a certain temperature range, R1, S1, S2, and S3 having known fixed volume. The sample temperatures will be monitored by thermocouple TC while the pressures in R1 an S1, S2, S3 will be measured using a digital pressure transducer. The maximum operating pressure of the pressure transducer is 20 bar and calibrated with an accuracy of ±0.01 bar. High purity hydrogen is being used in the system and the amount of samples for the study is between 1.0-2.0 grams. The system was calibrated using helium gas without any samples in S1, S2 an S3. This will provide a correction factor during the adsorption process providing an adsorption free reference point when using hydrogen gas resulting in a more accurate reading of the adsorption process by eliminating the errors caused by temperature expansion effects and other non-adsorption related phenomena. The ideal gas equation of state is applied to calculate the hydrogen adsorption capacity based on the differential pressure measurements. Activated carbon with a surface area of 644.87 m 2 /g showed a larger amount of adsorption as compared to multiwalled nanotubes (commercial) with a surface area of 119.68 m 2 /g. This study als indicated that there is a direct correlation between the amounts of hydrogen adsorbed an surface area of the carbon materials under the conditions studied and that the adsorption

  15. Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2).

    Science.gov (United States)

    Chew, Thiam-Leng; Ahmad, Abdul L; Bhatia, Subhash

    2010-01-15

    Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed. Copyright 2009 Elsevier B.V. All rights reserved.

  16. A comparative study of carbon dioxide adsorption on multi-walled carbon nanotubes versus activated charcoal

    Science.gov (United States)

    Khalili, S.; Ghoreyshi, A. A.; Jahanshahi, M.; Davoodi, M.

    2012-09-01

    In this study, the quilibrium adsorption of CO2 on activated charcoal and multi-walled carbon nanotube (MWCNT) were experimentally investigated at temperature range of 298-318 K and pressures up to 40 bars. The maximum storage capacity for both materials was obtained at lowest temperature and highest pressure under study. The amount of CO2 adsorbed on MWCNT is 2 times higher than that of activated Charcoal whereas the specific surface area of activated carbon is aboute 2 times higher than MWNT. The experimental data of CO2 adsorption have been analyzed using different model isotherms such as the Freundlich and Langmuir. Heat of adsorption evaluated from a set of isotherms based on the Clausius-Clapeyron equation indicated physical nature of adsorption mechanism.

  17. Membrane and Adsorption Processes for Removing of Organics and Inorganics from Urban Wastewaters

    OpenAIRE

    Majlinda Daci-Ajvazi; Bashkim Thaçi; Nexhat Daci; Salih Gash

    2016-01-01

    Since in Kosovo there are still no water purification plants and untreated wastewaters are discharged in environment, in this paper we’ve studied methods for removing of different organic and inorganic pollutants from Kosovo urban wastewaters. For best results we’ve used two methods, reverse osmosis and adsorption. For reverse osmosis, all samples were pretreated with coagulant (FeSO4) and flocculant (CaO) and then treated with reverse osmosis membranes. For adsorption, we used Kosovo coal as...

  18. In vitro adsorption study of fluoxetine in activated carbons and activated carbon fibres

    Energy Technology Data Exchange (ETDEWEB)

    Nabais, J.M. Valente; Mouquinho, A.; Galacho, C.; Carrott, P.J.M.; Ribeiro Carrott, M.M.L. [Centro de Quimica de Evora e Departamento de Quimica da Universidade de Evora, Rua Romao Ramalho no. 59, 7000-671 Evora (Portugal)

    2008-05-15

    We study the in vitro adsorption of fluoxetine hydrochloride by different adsorbents in simulated gastric and intestinal fluid, pH 1.2 and 7.5, respectively. The tested materials were two commercial activated carbons, carbomix and maxsorb MSC30, one activated carbon fibre produced in our laboratory and also three MCM-41 samples, also produced by us. Selected samples were modified by liquid phase oxidation and thermal treatment in order to change the surface chemistry without significant modifications to the porous characteristics. The fluoxetine adsorption follows the Langmuir model. The calculated Q{sub 0} values range from 54 to 1112 mg/g. A different adsorption mechanism was found for the adsorption of fluoxetine in activated carbon fibres and activated carbons. In the first case the most relevant factors are the molecular sieving effect and the dispersive interactions whereas in the activated carbons the mechanism seams to be based on the electrostatic interactions between the fluoxetine molecules and the charged carbon surface. Despite the different behaviours most of the materials tested have potential for treating potential fluoxetine intoxications. (author)

  19. Adsorption of triton X100 and potassium hydrogen phthalate on granular activated carbon from date pits

    Energy Technology Data Exchange (ETDEWEB)

    Merzougui, Z.; Nedjah, S.; Azoudj, Y.; Addoun, F. [Laboratoire d' etude physic-chimique des materiaux et application a l' environnement, Faculte de Chimie, USTHB (Algeria)], E-mail: zmerzougi@yahoo.fr

    2011-07-01

    Activated carbons, thanks to their versatility, are being used in the water treatment sector to absorb pollutants. Several factors influence the adsorption capacity of activated carbon and the aim of this study was to assess the effects of the porous texture and chemical nature of activated carbons on the adsorption of triton X100 and potassium hydrogen phthalate. Activated carbons used in this study were prepared from date pits with ZnCl2, KOH and H3PO4 by carbonization without adjuvant and adsorption of triton X100 and potassium hydrogen phthalate was conducted at 298K. Results showed that activated carbons prepared from date pits have a great potential for removing organic and inorganic pollutants from water and that the adsorption potential depends on the degree of activation of the activated carbons and on the compounds to absorb. This study highlighted that an increase of the carbon surface area and porosity results in a better adsorption capacity.

  20. Molecular modeling of membrane tube pearling and the effect of nanoparticle adsorption.

    Science.gov (United States)

    Yue, Tongtao; Zhang, Xianren; Huang, Fang

    2014-06-14

    The shape transformation of membrane tubes, also known as pearling, is thought to play an important role in a variety of cellular activities, like intracellular transport. Despite considerable experiments have investigating this phenomenon, the detailed molecular mechanism as well as how environmental factors affect the tube pearling instability is still ambiguous. In this work, we use computer simulation techniques to obtain a molecular-level insight into the tube pearling process. We find that the tube morphology is strongly determined by the water pressure inside membrane tubes. For example, the tube shrinkage and subsequent bending is observed when we decrease the inner water pressure. Contrarily, as we increase the inner water pressure, the tube pearling tends to occur in order to reduce the surface energy. Besides, our simulations show that the membrane tube pearling is regulated by the adsorption of nanoparticles (NPs) in two competing ways. One is that the NP adsorption can exert an additional membrane tension and thus promote the pearling and subsequent division of membrane tubes. On the other hand, the NP adsorption can locally rigidify the membrane and thus contrarily restrain the tube pearling. Therefore, the NP size, NP concentration and NP-membrane adhesion strength will collectively regulate the tube pearling process.

  1. Adsorption mechanism of different organic chemicals on fluorinated carbon nanotubes.

    Science.gov (United States)

    Li, Hao; Zheng, Nan; Liang, Ni; Zhang, Di; Wu, Min; Pan, Bo

    2016-07-01

    Multi-walled carbon nanotubes (MC) were fluorinated by a solid-phase reaction method using polytetrafluoroethylene (PTFE). The surface alteration of carbon nanotubes after fluorination (MC-F) was confirmed based on surface elemental analysis, TEM and SEM. The incorporation of F on MC surface was discussed as F incorporation on carbon defects, replacement of carboxyl groups, as well as surface coating of PTFE. The adsorption performance and mechanisms of MC-F for five kinds of representative organic compounds: sulfamethoxazole (SMX), ofloxacin (OFL), norfloxacin (NOR), bisphenol a (BPA) and phenanthrene (PHE) were investigated. Although BET-N2 surface area of the investigated CNTs decreased after fluorination, the adsorption of all five chemicals increased. Because of the glassification of MC-F surface coating during BET-N2 surface area measurement, the accessible surface area of MC-F was underestimated. Desorption hysteresis was generally observed in all the sorption systems in this study, and the desorption hysteresis of MC-F were stronger than the pristine CNTs. The enhanced adsorption of MC-F may be attributed the pores generated on the coated PTFE and the dispersed CNT aggregates due to the increased electrostatic repulsion after fluorination. The rearrangement of the bundles or diffusion of the adsorbates in MC-F inner pores were the likely reason for the strong desorption hysteresis of MC-F. The butterfly structure of BPA resulted in its high sorption and strong desorption hysteresis. The exothermic sorption character of OFL on CNTs resulted in its strong desorption hysteresis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Adsorption of an Uranyl Carbonate Complex onto an Amidoxime Resin

    Energy Technology Data Exchange (ETDEWEB)

    Joe, Kih-Soo; Lee, Eil-Hee; Kim, Kwang-Wook; Jung, Euo-Chang; Jee, Kwang-Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-10-15

    Uranium is a major element in the management of spent nuclear fuel or radioactive waste. Uranium is also present in sea water at a trace level ({approx}3ppb). Usually, an acid medium in a solvent extraction or ion exchange system have been used for the separation of uranium from a radioactive waste solution. Especially, some adsorbants containing amidoxime functional groups selective for the uranyl ion have been developed for the recovery of uranium in sea water. An amidoxime resin as an anion exchanger synthesized using divinylbenzene copolymer as a supporting material was applied for the separation of uranium and plutonium from simulated fission products in carbonate solution by making an uranyl tricarbonate complex, UO{sub 2}(CO{sub 3}){sub 3}{sup 4-}, in an alkaline solution of a carbonate (pH>8). A carbonate leaching of uranium from uranium contaminated soils was also successfully performed using a sodium carbonate and a sodium bicarbonate solution. In this work, the distribution coefficients of uranyl ions were measured for the amidoxime resins with a variation of carbonate concentration and the pH of the solutions as a preliminary work for a spent fuel treatment with a strong alkaline carbonate solution because this system has an advantage to reduce a high level waste volume by a selective oxidation and an adsorption of uranium from spent fuels.

  3. Removal of carbon dioxide in reprocessing spent nuclear fuel off gas by adsorption

    International Nuclear Information System (INIS)

    Fukumatsu, Teruki; Munakata, Kenzo; Tanaka, Kenji; Yamatsuki, Satoshi; Nishikawa, Masabumi

    1998-01-01

    The off gas produced by reprocessing spent nuclear fuel includes various radioactivities and these nuclei should be removed. In particular, 14 C mainly released as the form of carbon dioxide is one of the most required gaseous radioactivities to be removed because it has long a half-life. One of the methods to remove gaseous nuclei is the use of adsorption technique. The off gas contains water vapor which influences adsorption process of carbon dioxide. In this report, behavior of adsorption of carbon dioxide on various adsorbent and influence on adsorption behavior of carbon dioxide by containing water vapor are discussed. (author)

  4. ADSORPTION OF FOOD COLORING ALLURA RED DYE (E129 FROM AQUEOUS SOLUTIONS USING ACTIVATED CARBON

    Directory of Open Access Journals (Sweden)

    Saad A Alkahtani

    2017-09-01

    Full Text Available The adsorption behavior of Allura red (E129 from aqueous solutions onto activated carbon was successfully investigated. All factors affecting the adsorption process were carefully studied and the conditions were optimized. Adsorption of E129 onto activated carbon was found to increase by decreasing the mass of activated carbon, pH and ionic strength of the solution and by increasing temperature. The adsorption capacity of the activated carbon for Allura red was relatively high. Under the optimum conditions, the maximum adsorption capacity for E129 dye was 72.85 mg/g. Three adsorption models; Langmuir, Freundlich and Temkin model were investigated regarding the adsorption of E129. The models’ parameters KL, qm, R2, (n were determined and found to be 0.0222, 72.85 mg/g, 0.9057-0.9984, and 0.992, respectively. Also, pseudo first and second-order kinetic models were tested to determine the best-fit model to the adsorption of E129 dye onto activated carbon. The results showed that the adsorption of E129 onto activated carbon obeyed both the Freundlich isotherm and pseudo second-order kinetic models. Moreover, thermodynamic studies indicated that the adsorption of E129 dye onto the activated carbon was spontaneous. 

  5. Simulation of adsorption of DNA on carbon nanotubes.

    Science.gov (United States)

    Zhao, Xiongce; Johnson, J Karl

    2007-08-29

    We report molecular dynamics simulations of DNA adsorption on a single-walled carbon nanotube (SWNT) in an aqueous environment. We have modeled a DNA segment with 12 base pairs (Dickerson dodecamer) and a (8,8) SWNT in water, with counterions to maintain total charge neutrality. Simulations show that DNA binds to the external surface of an uncharged or positively charged SWNT on a time scale of a few hundred picoseconds. The hydrophobic end groups of DNA are attracted to the hydrophobic SWNT surface of uncharged SWNTs, while the hydrophilic backbone of DNA does not bind to the uncharged SWNT. The binding mode of DNA to charged SWNTs is qualitatively different from uncharged SWNTs. The phosphodiester groups of the DNA backbone are attracted to a positively charged SWNT surface while DNA does not adsorb on negatively charged SWNTs. There is no evidence for canonical double-stranded DNA wrapping around either charged or uncharged SWNTs on the very short time scales of the simulations. The adsorption process appears to have negligible effect on the internal stacking structure of the DNA molecule but significantly affects the A to B form conversion of A-DNA. The adsorption of A-DNA onto an uncharged SWNT inhibits the complete relaxation of A-DNA to B-DNA within the time scale of the simulations. In contrast, binding of the A-DNA onto a positively charged SWNT may promote slightly the A to B conversion.

  6. Aqueous adsorption and removal of organic contaminants by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jin-Gang, E-mail: yujg@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Zhao, Xiu-Hui; Yang, Hua [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Chen, Xiao-Hong [Collaborative Innovation Center of Resource-conserving and Environment-friendly Society and Ecological Civilization, Changsha, Hunan 410083 (China); Yang, Qiaoqin [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada); Yu, Lin-Yan [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Jiang, Jian-Hui [College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082 (China); Chen, Xiao-Qing, E-mail: xqchen@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China)

    2014-06-01

    Organic contaminants have become one of the most serious environmental problems, and the removal of organic contaminants (e.g., dyes, pesticides, and pharmaceuticals/drugs) and common industrial organic wastes (e.g., phenols and aromatic amines) from aqueous solutions is of special concern because they are recalcitrant and persistent in the environment. In recent years, carbon nanotubes (CNTs) have been gradually applied to the removal of organic contaminants from wastewater through adsorption processes. This paper reviews recent progress (145 studies published from 2010 to 2013) in the application of CNTs and their composites for the removal of toxic organic pollutants from contaminated water. The paper discusses removal efficiencies and adsorption mechanisms as well as thermodynamics and reaction kinetics. CNTs are predicted to have considerable prospects for wider application to wastewater treatment in the future. - Highlights: • We summarize the most recent research progress of CNTs for removal of organics. • Adsorption mechanisms between CNTs and organics were elucidated in detail. • The developing trends and prospects of CNTs for removal of organics were discussed.

  7. Adsorption of pharmaceuticals to microporous activated carbon treated with potassium hydroxide, carbon dioxide, and steam.

    Science.gov (United States)

    Fu, Heyun; Yang, Liuyan; Wan, Yuqiu; Xu, Zhaoyi; Zhu, Dongqiang

    2011-01-01

    Adsorption of sulfapyridine, tetracycline, and tylosin to a commercial microporous activated carbon (AC) and its potassium hydroxide (KOH)-, CO-, and steam-treated counterparts (prepared by heating at 850°C) was studied to explore efficient adsorbents for the removal of selected pharmaceuticals from water. Phenol and nitrobenzene were included as additional adsorbates, and nonporous graphite was included as a model adsorbent. The activation treatments markedly increased the specific surface area and enlarged the pore sizes of the mesopores of AC (with the strongest effects shown on the KOH-treated AC). Adsorption of large-size tetracycline and tylosin was greatly enhanced, especially for the KOH-treated AC (more than one order of magnitude), probably due to the alleviated size-exclusion effect. However, the treatments had little effect on adsorption of low-size phenol and nitrobenzene due to the predominance of micropore-filling effect in adsorption and the nearly unaffected content of small micropores causative to such effect. These hypothesized mechanisms on pore-size dependent adsorption were further tested by comparing surface area-normalized adsorption data and adsorbent pore size distributions with and without the presence of adsorbed antibiotics. The findings indicate that efficient adsorption of bulky pharmaceuticals to AC can be achieved by enlarging the adsorbent pore size through suitable activation treatments. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  8. Fabrication of electrospun polyacrylonitrile ion-exchange membranes for application in lysozyme adsorption

    Directory of Open Access Journals (Sweden)

    2011-04-01

    Full Text Available Ion exchange (IEX chromatography is commonly used in separation and purification systems. However, micropore blockage within its resin structure can easily lead to a reduction in the effectiveness of purification. To tackle this problem, we adopted the concept of membrane separation by combining electrospinning techniques with rapid alkaline hydrolysis to prepare a weak acid IEX nanofibrous membrane (AEA-COOH, consisting of polyethyleneterephthalate (PET meltblown fabric as a supporting layer, with upper and lower IEX layers consisting of polyacrylonitrile (PAN nanofibrous membranes. To determine the characteristics of the AEA-COOH membrane, we used the commercial product Sartobind© C IEX membrane as the standard of comparison. Results showed that the base weight and thickness of AEACOOH were 33 and 64%, relative to Sartobind© C membrane. The thermo-degradable temperature of AEA-COOH membrane (320°C was far higher than that of Sartobind© C (115°C, indicating high thermal stability. Finally, comparisons between the lysozyme adsorption rates and capacity of various IEX membranes confirmed that AEA-COOH was lighter, thinner, faster, possessing higher protein adsorption efficiency than Sartobind© C membrane.

  9. Adsorption mechanism of sodium dodecyl benzene sulfonate on carbon blacks by adsorption isotherm and zeta potential determinations.

    Science.gov (United States)

    Zhao, Yapei; Lu, Pei; Li, Caiting; Fan, Xiaopeng; Wen, Qingbo; Zhan, Qi; Shu, Xin; Xu, Tieliang; Zeng, Guangming

    2013-01-01

    Surfactant solutions were propounded to remove fine and hydrophobic carbon black particles from coal-fired flue gas. The adsorption mechanisms between sodium dodecyl benzene sulfonate (SDBS, an anionic surfactant) and carbon black particles in suspension were investigated. The influence of inorganic salt (NaCl) was also considered. As results showed, hydrophobic interactions contributed to the strong adsorption between SDBS and carbon black particles in the absence of NaCl, and adding NaCl affected the adsorption process. The adsorption amount of SDBS significantly increased when NaCl was added into the SDBS solution; however, when SDBS was in low concentration, the amount of adsorbed SDBS, which was responsible for the shift of zeta potentials, varied little under different concentrations of NaCl. This indicated that the adsorption of SDBS was mainly caused by hydrophobic interaction and Na+ could not change the adsorption of SDBS on adsorption site when SDBS was in low concentration. Moreover, the adsorbed SDBS and Na+ were retained in the Stern layer.

  10. Adsorption Of Blue-Dye On Activated Carbons Produced From Rice ...

    African Journals Online (AJOL)

    The results obtained indicated that ferric chloride-activated carbons produced from coconut coirpith are better adsorbents for blue-dye than those prepared from rice husk. The adsorption data fit well with Freundlich adsorption isotherm. The adsorption capacity calculated from the Freundlich isotherm was in the range of ...

  11. Adsorption of halogenated hydrocarbons from gaseous streams by amberlite XAD-4 resin and activated carbon: equilibria

    NARCIS (Netherlands)

    Rexwinkel, Glenn; Rexwinkel, G.; Heesink, Albertus B.M.; van Swaaij, Willibrordus Petrus Maria

    1999-01-01

    Single-solute adsorption equilibria have been measured for the adsorption of the gaseous solutes chloroform, chlorobenzene, and 1,1,1-trichloroethane onto Amberlite XAD-4 resin. For 1,1,1-trichloroethane the adsorption equilibrium has also been measured with activated carbon Norit ROW 0.8 SUPRA as a

  12. Adsorption of vitamin K-dependent proteins to live cell membranes measured under flow conditions.

    Science.gov (United States)

    McGee, M P; Teuschler, H

    1999-07-01

    Mechanisms mediating initial adsorption of coagulation proteins to live cells were investigated. Adsorption kinetics were examined under varying flow conditions using tracer-dilution techniques in perfused spherical monolayers of cells expressing tissue factor. At biologically relevant time and concentration ranges, rates exceeded by 2-12 fold the theoretical maximum calculated for steady-state diffusion. Rates were correlated with aqueous-phase flux of reactants and were found to be largely independent of the density of reactive sites on the membrane. Average adsorption rate of factor VIIa at 4 etaM and flow velocity of 0.8 etam s(-1) was 5 x 10(7) s(-1) cm(-2). Adsorption rates of homologous coagulation factors IX and X under similar conditions were 5 and 9 x 10(7) s(-1)cm(-2). Results indicate that flow can effectively increase the rate of coagulation factor adsorption to the membrane of live cells. They also imply that factors affecting blood flow velocity and vessel permeability influence the rate of membrane-dependent coagulation reactions.

  13. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION

    International Nuclear Information System (INIS)

    Ida, Jun-ichi; Yang, Zhaohui; Lin, Jerry Y.S.

    2002-01-01

    A new CO 2 semi-permeable dense inorganic membrane consisting of a porous metal phase and molten carbonate was proposed. A simple direct infiltration method was used to synthesize the metal-carbonate dual-phase membrane. Hermetic (gas-tight) dual phase membrane was successfully obtained. Permeation data showed that nitrogen or helium is not permeable through the membrane (only CO 2 , with O 2 can permeate through the membrane based on transport mechanism)

  14. Effect of microbial community structure on organic removal and biofouling in membrane adsorption bioreactor used in seawater pretreatment

    KAUST Repository

    Jeong, Sanghyun

    2016-03-03

    Membrane bioreactors (MBRs) were operated on-site for 56 d with different powdered activated carbon (PAC) dosages of 0, 1.5 and 5.0 g/L to pretreat seawater for reverse osmosis desalination. It was hypothesized that PAC would stimulate adsorption and biological degradation of organic compounds. The microbial communities responsible for biofouling on microfiltration (MF) membranes and biological organic removal in MBR were assessed using terminal restriction fragment length polymorphism fingerprinting and 454-pyrosequencing. The PAC addition improved assimilable organic carbon removal (53-59%), and resulted in reduced biofouling development on MF (> 50%) with only a marginal development in trans-membrane pressure. Interestingly, the bacterial community composition was significantly differentiated by the PAC addition. Cyanobacterium, Pelagibaca and Maricoccus were dominant in the PAC-free conditions, while Thiothrix and Sphingomonas were presumably responsible for the better reactor performances in PAC-added conditions. In contrast, the archaeal communities were consistent with predominance of Candidatus Nitrosopumilus. These data therefore show that the addition of PAC can improve MBR performance by developing different bacterial species, controlling AOC and associated biofouling on the membranes.

  15. Carbon dioxide adsorption on H2 O 2 treated single-walled carbon nanohorns

    Science.gov (United States)

    Migone, Aldo; Krungleviciute, Vaiva; Banjara, Shree; Yudasaka, Masako; Iijima, Sumio

    2011-03-01

    Carbon nanohorns are closed single-wall structures with a hollow interior. Unlike SWNTs, which assemble into cylindrical bundles, nanohorns form spherical aggregates. In our experiments we used dahlia-like carbon nanohorn aggregates. Our sample underwent treatment with H2 O2 which opened access to the interior spaces of the individual nanohorns. We measured carbon dioxide adsorption at several temperatures between 167 and 195 K. We calculated the isosteric heat as a function of loading, and the binding energy values for CO2 on the nanohorn aggregates from the isotherm data. Results on the H2 O2 -treated nanohorns will be compared with those obtained on other carbon substrates. We have also determined detailed equilibration profiles for CO2 adsorption on the nanohorn aggregates; these results will also be presented. This work was supported by the NSF through grants DMR-1006428 and DMR-0705077.

  16. Adsorption of Volatile Organic Compounds from Aqueous Solution by Granular Activated Carbon in Batch System

    International Nuclear Information System (INIS)

    Zeinali, F.; Ghoreyshi, A. A.; Najafpour, G.

    2011-01-01

    Chlorinated hydrocarbons and aromatics are the major volatile organic compounds that contaminate the ground water and industrial waste waters. The best way to overcome this problem is to recover the dissolved compounds in water. In order to evaluate the potential ability of granular activated carbon for recovery of volatile organic compounds from water, the equilibrium adsorption was investigated. This study deals with the adsorption of dichloromethane as a typical chlorinated volatile organic compound and toluene as the representative of aromatic volatile organic compounds on a commercial granular activated carbon. The adsorption isotherms of these two volatile organic compounds on granular activated carbon were measured at three different temperatures, toluene at 293, 303 and 313 K and dichloromethane at 298, 303 and 313 K within their solubility concentration range in water. The maximum adsorption capacity of dichloromethane and toluene adsorption by granular activated carbon was 4 and 0.2 mol/Kg-1, respectively. The experimental data obtained were correlated with different adsorption isotherm models. The Langmuir model was well adapted to the description of dichloromethane adsorption on granular activated carbon at all three temperatures, while the adsorption of toluene on granular activated carbon was found to be well described by the Langmuir-BET hybrid model at all three temperatures. The heat of adsorption was also calculated based on the thermodynamic equation of Clausius Clapeyron, which indicates the adsorption process is endothermic for both compounds.

  17. Carbon monoxide adsorption on silver doped gold clusters.

    Science.gov (United States)

    De Haeck, Jorg; Veldeman, Nele; Claes, Pieterjan; Janssens, Ewald; Andersson, Mats; Lievens, Peter

    2011-03-24

    Well controlled gas phase experiments of the size and dopant dependent reactivity of gold clusters can shed light on the surprising discovery that nanometer sized gold particles are catalytically active. Most studies that investigate the reactivity of gold clusters in the gas phase focused on charged, small sized clusters. Here, reactivity measurements in a low-pressure reaction cell were performed to investigate carbon monoxide adsorption on neutral bare and silver doped gold clusters (Au(n)Ag(m); n = 10-45; m = 0, 1, 2) at 140 K. The size dependence of the reaction probabilities reflects the role of the electronic shells for the carbon monoxide adsorption, with closed electronic shell systems being the most reactive. In addition, the cluster's reaction probability is reduced upon substitution of gold atoms for silver. Inclusion of a single silver atom causes significant changes in the reactivity only for a few cluster sizes, whereas there is a more general reduction in the reactivity with two silver atoms in the cluster. The experimental observations are qualitatively explained on the basis of a Blyholder model, which includes dopant induced features such as electron transfer from silver to gold, reduced s-d hybrization, and changes in the cluster geometry.

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

    NARCIS (Netherlands)

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

    1998-01-01

    In the present in vitro study we investigated filtration and adsorption of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8) during predilution and postdilution hemofiltration with polysulfone, polyacrylonitrile, polyamide and cellulose triacetate membranes. The

  19. A metal ion charged mixed matrix membrane for selective adsorption of hemoglobin

    NARCIS (Netherlands)

    Tetala, K.K.R.; Skrzypek, Katarzyna; Levisson, M.; Stamatialis, Dimitrios

    2013-01-01

    In this work, we developed a mixed matrix membrane by incorporating 20–40 μm size iminodiacetic acid modified immobeads within porous Ethylene vinyl alcohol (EVAL) polymer matrix. The MMM were charged with copper ions for selective adsorption of bovine hemoglobin in presence of bovine serum albumin.

  20. Dye-Affinity Nanofibrous Membrane for Adsorption of Lysozyme: Preparation and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Steven Sheng-Shih Wang

    2018-01-01

    Full Text Available Polyacrylonitrile (PAN nanofibrous membrane was prepared by an electrospinning technique. After heat treatment and alkaline hydrolysis, the weak ion exchange membrane was grafted with chitosan molecule and then covalently immobilized with a Cibacron Blue F3GA (CB. Fibre diameter, porosity and pore size of the membrane and immobilized dye density were characterized. Furthermore, the membrane was applied to evaluate the binding performance of lysozyme under various operating parameters (pH, chitosan mass per volume ratio, dye concentration, ionic strength and temperature in batch mode. The experimental results were directly applied to purify lysozyme from chicken egg white by membrane chromatography. The results showed that the capture efficiency, recovery yield and purification factor were 90 and 87 %, and 47-fold, respectively, in a single step. The binding capacity remained consistent after five repeated cycles of adsorption-desorption operations. This work demonstrates that the dye-affinity nanofibrous membrane holds great potential for purification of lysozyme from real feedstock.

  1. Adsorption of aromatic organic contaminants by graphene nanosheets: comparison with carbon nanotubes and activated carbon.

    Science.gov (United States)

    Apul, Onur Guven; Wang, Qiliang; Zhou, Yang; Karanfil, Tanju

    2013-03-15

    Adsorption of two synthetic organic compounds (SOCs; phenanthrene and biphenyl) by two pristine graphene nanosheets (GNS) and one graphene oxide (GO) was examined and compared with those of a coal base activated carbon (HD4000), a single-walled carbon nanotube (SWCNT), and a multi-walled carbon nanotube (MWCNT) in distilled and deionized water and in the presence of natural organic matter (NOM). Graphenes exhibited comparable or better adsorption capacities than carbon nanotubes (CNTs) and granular activated carbon (GAC) in the presence of NOM. The presence of NOM reduced the SOC uptake of all adsorbents. However, the impact of NOM on the SOC adsorption was smaller on graphenes than CNTs and activated carbons. Furthermore, the SOC with its flexible molecular structure was less impacted from NOM preloading than the SOC with planar and rigid molecular structure. The results indicated that graphenes can serve as alternative adsorbents for removing SOCs from water. However, they will also, if released to environment, adsorb organic contaminants influencing their fate and impact in the environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Adsorption behavior of magnetite nanoparticles into the DPPC model membranes

    International Nuclear Information System (INIS)

    Hao, Changchun; Li, Junhua; Mu, Wenning; Zhu, Lingqing; Yang, Jiaxiang; Liu, Hongwei; Li, Bin; Chen, Shi; Sun, Runguang

    2016-01-01

    Graphical abstract: A represents the state when DPPC was spread on air/water interface at 5 mN/m surface pressures. DPPC is in the liquid expanded state at the interface. B represents 15 mN/m surface pressures and DPPC monolayer is in the liquid condensed state at the interface. - Highlights: • The adsorption of Fe 3 O 4 nanoparticles on DPPC monolayer has been investigated. • The lifting area/molecule of DPPC monolayers increased with Fe 3 O 4 increasing. • The π–t curves were well fitted by single exponential association equation. • AFM images depended on surface pressure and concentration in subphase. - Abstract: In this report, we have studied the adsorption behavior of Fe 3 O 4 nanoparticles into dipalmitoylphosphatidylcholine (DPPC) monolayer. Adsorption kinetics (π–t) process as well as the surface pressure (π–A) isotherms were monitored by Langmuir Wilhelmy plate. The measurement data indicated the Fe 3 O 4 nanoparticles incorporated into the monolayer at the air–water interface. The lifting area/molecule isotherms of DPPC monolayers increased with the increasing concentration of Fe 3 O 4 in the subphase, however, the values of elasticity reduced. The curves of π–t were well fitted by single exponential association equation. Observation by atomic force microscopy (AFM) on monolayers extracted at 5 mN/m and 15 mN/m suggested that the different interaction of Fe 3 O 4 with DPPC monolayer depended on surface pressure of monolayers and concentration in the subphase. The results of observations were in agreement with the fitted results.

  3. Polydopamine-mediated surface functionalization of electrospun nanofibrous membranes: Preparation, characterization and their adsorption properties towards heavy metal ions

    International Nuclear Information System (INIS)

    Wu, Chunlin; Wang, Heyun; Wei, Zhong; Li, Chuan; Luo, Zhidong

    2015-01-01

    Graphical abstract: - Highlights: • A simple and versatile approach to produce PEI-functionalized nanofibers. • Novel PEI-functionalized PVC nanofibrous membrane was prepared. • Adsorption of PVC@PDA and PVC@PDA-PEI nanofibrous membranes for Cu 2+ was tested. • Isotherms, kinetic model and thermodynamic parameters were investigated. • Adsorption mechanism of Cu 2+ on modified membranes was inferred. - Abstract: In this paper, a simple and versatile approach for the fabrication of a polyethyleneimine (PEI)-functionalized nanofibrous membrane utilizing polydopamine (PDA) as a mediator is proposed. The morphology and structure of the PDA-coated and PEI-grafted nanofibrous membranes were confirmed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Due to a large specific surface area and long fibrous morphology, the synthesized membranes were used as novel adsorbents for copper ion (Cu 2+ ) removal from aqueous solutions. The adsorption of Cu 2+ was investigated on the synthesized membranes regarding the membrane dosages, initial solution pH values, initial solution concentrations, contact times and temperatures. In addition, the adsorption equilibrium data of PEI-grafted membranes were well fitted with the Langmuir adsorption isotherm, and a maximum adsorption capacity value of 33.59 mg g −1 was determined (while it was 21.94 mg g −1 for the PDA-coated membranes). The thermodynamic parameters indicated that Cu 2+ absorption was a spontaneous and exothermic adsorption process. In addition, XPS peak differentiation imitating analysis permitted the proposal of a copper-amine coordination adsorption mechanism that can be used to explain changes in the adsorption properties compared to PDA coating nanofibrous membranes

  4. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane

    Directory of Open Access Journals (Sweden)

    A. G. Gaikwad

    2012-06-01

    Full Text Available Transport of carbonate ions was explored through fiber supported solid membrane. A novel fiber supported solid membrane was prepared by chemical modification of cellulose fiber with citric acid, 2′2-bipyridine and magnesium carbonate. The factors affecting the permeability of carbonate ions such as immobilization of citric acid-magnesium metal ion -2′2-bipyridine complex (0 to 2.5 mmol/g range over cellulose fiber, carbon-ate ion concentration in source phase and NaOH concentration in receiving phase were investigated. Ki-netic of carbonate, sulfate, and nitrate ions was investigated through fiber supported solid membrane. Transport of carbonate ions with/without bubbling of CO2 (0 to 10 ml/min in source phase was explored from source to receiving phase. The novel idea is to explore the adsorptive transport of CO2 from source to receiving phase through cellulose fiber containing magnesium metal ion organic framework. Copyright © 2012 BCREC UNDIP. All rights reserved.Received: 25th November 2011; Revised: 17th December 2011; Accepted: 19th December 2011[How to Cite: A.G. Gaikwad. (2012. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 49– 57.  doi:10.9767/bcrec.7.1.1225.49-57][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1225.49-57 ] | View in 

  5. Effect of hydrophobicity of pharmaceuticals and personal care products for adsorption on activated carbon: Adsorption isotherms, kinetics and mechanism.

    Science.gov (United States)

    Kaur, Harkirat; Bansiwal, Amit; Hippargi, Girivyankatesh; Pophali, Girish R

    2017-09-11

    Adsorption of three pharmaceuticals and personal care products (PPCPs), namely caffeine, ibuprofen and triclosan on commercial powdered activated carbon was examined in aqueous medium. The contaminants were chosen based on their diverse log K ow (octanol-water partition coefficient) viz. - 0.07 for caffeine, 3.97 for ibuprofen and 4.76 for triclosan to examine the role of hydrophobicity on adsorption process. The adsorbent characterisation was achieved using BET surface area, SEM, pore size distribution studies and FTIR. Influence of mass of PAC, contact time, solution pH and initial concentration on adsorption capacity of PAC was studied. Adsorption isotherms and kinetics were applied to establish the mechanism of adsorption. The kinetics followed pseudo-second order with physisorption occurring through particle diffusion. The Freundlich model fitted best among the isotherm models. The adsorption capacity increased in the order CFN hydrophobicity (log K ow ), molecular weight and decreasing water solubility, respectively. We conclude that micro-pollutant hydrophobicity contributes towards adsorption on activated carbon.

  6. Activated carbon-supported CuO nanoparticles: a hybrid material for carbon dioxide adsorption

    Science.gov (United States)

    Boruban, Cansu; Esenturk, Emren Nalbant

    2018-03-01

    Activated carbon-supported copper(II) oxide (CuO) nanoparticles were synthesized by simple impregnation method to improve carbon dioxide (CO2) adsorption capacity of the support. The structural and chemical properties of the hybrid material were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (https://www.google.com.tr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CCsQFjAC&url=http%3A%2F%2Fwww.intertek.com%2Fanalytical-laboratories%2Fxrd%2F&ei=-5WZVYSCHISz7Aatqq-IAw&usg=AFQjCNFBlk-9wqy49foh8tskmbD-GGbG9g&sig2=eKrhYjO75rl_Id2sLGpq4w&bvm=bv.96952980,d.bGg) (XRD), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS), and Brunauer-Emmett-Teller (BET) analyses. The analyses showed that CuO nanoparticles are well-distributed on the activated carbon surface. The CO2 adsorption behavior of the activated carbon-supported CuO nanoparticles was observed by thermogravimetric analysis (TGA), temperature programmed desorption (TPD), Fourier transform infrared (FTIR), and BET analyses. The results showed that CuO nanoparticle loading on activated carbon led to about 70% increase in CO2 adsorption capacity of activated carbon under standard conditions (1 atm and 298 K). The main contributor to the observed increase is an improvement in chemical adsorption of CO2 due to the presence of CuO nanoparticles on activated carbon.

  7. Thermodynamics of the Cu(II) adsorption on thin vanillin-modified chitosan membranes

    International Nuclear Information System (INIS)

    Cestari, Antonio R.; Vieira, Eunice F.S.; Mattos, Charlene R.S.

    2006-01-01

    In this work, low-density vanillin-modified thin chitosan membranes were synthesized and characterized. The membranes were utilized as adsorbent for the removal of Cu(II) from aqueous solutions. The experimental data obtained in batch experiments at different temperatures were fitted to the Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. The adsorption equilibrium data fitted well with the Langmuir model (average R 2 > 0.99). Interactions thermodynamic parameters (Δ int H, Δ int G, and Δ int S), as well as the interaction thermal effects (Q int ) were determined from T = (298 to 333) K. The thermodynamic parameters, the Dubinin-Radushkevick equation and the comparative values of Δ int H for some Cu(II)-adsorbent interactions suggested that the adsorption of Cu(II) ions to vanillin-chitosan membranes show average results for both the diffusional (endothermic) and chemical bonding (exothermic) processes in relation to the temperature range studied

  8. Facile and green fabrication of cation exchange membrane adsorber with unprecedented adsorption capacity for protein purification.

    Science.gov (United States)

    Khan, M Kamran; Luo, Jianquan; Khan, Rashid; Fan, Jinxin; Wan, Yinhua

    2017-10-27

    Fabricating membrane adsorbers with high adsorption capacity and appreciable throughput for the separation and purification of protein products is challenging in biomedical and pharmaceutical industries. Herein, we report the synthesis of a novel membrane adsorber by functionalizing a nylon microfiltration membrane with alginate dialdehyde (ADA) followed by sulphonic addition, without any solvent usage, and its successful application in the purification of lysozyme. Taking advantage of abundant dual cation exchange (CEX) groups on sulphonic-ADA (S-ADA) ligands, this novel S-ADA-nylon membrane adsorber showed an unprecedented static binding capicity of 286mg/mL for lysozyme adsorption. Meanwhile, the prepared membrane adsorber could be easily regenerated (complete protein elution) under mild conditions and be reused at least for five times. Featured with a unique selectivity, the S-ADA-nylon membrane also captured lysozyme from chicken egg white solution with a high purity (100%) and a high recovery of 98%. The purified lysozyme showed similar specific activity as commercial product. The present work provides a facile, green and low-cost approach for the preparation of high-performance membrane adsorbers, which has a great potential in protein production. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

    Directory of Open Access Journals (Sweden)

    K. Rambabu

    2014-01-01

    Full Text Available A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate.

  10. Carbon Dioxide Adsorption in Nanopores of Coconut Shell Chars for Pore Characterization and the Analysis of Adsorption Kinetics

    Directory of Open Access Journals (Sweden)

    Chaiyot Tangsathitkulchai

    2016-01-01

    Full Text Available The uptake data of CO2 adsorption at 273 K by coconut shell chars prepared at various carbonization temperatures from 250 to 550°C were used for characterizing pore texture of chars as well as the analysis of CO2 adsorption kinetics. The equilibrium isotherms were used to determine the porous texture of chars, employing the DR equation and GCMC simulation. It was found that all the test chars contain micropores of a size range from 0.8 to 2.2 nm with the pore size distribution becoming wider for char prepared at a higher carbonization temperature. Porous properties of chars, including surface area, total pore volume, and the average pore size, appear to increase with an increasing carbonization temperature. The analysis of CO2 uptake during the transient measurement of isotherms revealed that the kinetics of CO2 adsorption is governed by the internal diffusional transport of the adsorptive molecules. The effective pore diffusivity characterizing this transport process increases with increasing CO2 loading and passes through a maximum at a certain loading. This maximum pore diffusivity shifts to a higher value as the carbonization temperature is increased. A semiempirical equation was developed to correlate the effective pore diffusivity of CO2 with the equilibrium adsorption loading and its predictive capability is satisfactory.

  11. Thermal desalination membranes: Carbon nanotubes keep up the heat

    Science.gov (United States)

    Boo, Chanhee; Elimelech, Menachem

    2017-07-01

    Applying high-potential alternating current to a carbon-nanotube-polymer composite film provides a self-heating membrane that enhances desalination performance of high-salinity brines by membrane distillation.

  12. Membranes prepared by radiation grafting of binary monomers for adsorption of heavy metals from industrial wastes

    Science.gov (United States)

    Hegazy, El-Sayed A.; Kamal, H.; Maziad, N.; Dessouki, A. M.

    1999-05-01

    Preparation of synthetic membranes using simultaneous radiation grafting of acrylic acid (AAc) and styrene (Sty) as individually and in binary monomer mixture onto low density polyethylene (LDPE) has been carried out. The effect of preparation conditions such as irradiation dose, monomer concentration, comonomer composition, and solvent on the grafting yield was investigated. Characterization and some properties of the prepared membranes using different analytical techniques are studied, accordingly the possibility of its practical use in industrial waste treatment is determined. The swelling behavior, electrical conductivity, thermal stability, and mechanical properties of the membranes were investigated as a function of the grafting degree. The prepared cation-exchange membranes possessed good electrical and mechanical properties, high thermal stability and possess good characteristics for separation processes. These membranes have also good affinity toward the adsorption or chelation with Fe 3+ and Pb 2+ ions either in mixture containing other metals or if exists alone in the waste solution.

  13. Adsorption of organic stormwater pollutants onto activated carbon from sewage sludge.

    Science.gov (United States)

    Björklund, Karin; Li, Loretta Y

    2017-07-15

    Adsorption filters have the potential to retain suspended pollutants physically, as well as attracting and chemically attaching dissolved compounds onto the adsorbent. This study investigated the adsorption of eight hydrophobic organic compounds (HOCs) frequently detected in stormwater - including four polycyclic aromatic hydrocarbons (PAHs), two phthalates and two alkylphenols - onto activated carbon produced from domestic sewage sludge. Adsorption was studied using batch tests. Kinetic studies indicated that bulk adsorption of HOCs occurred within 10 min. Sludge-based activated carbon (SBAC) was as efficient as tested commercial carbons for adsorbing HOCs; adsorption capacities ranged from 70 to 2800 μg/g (C initial  = 10-300 μg/L; 15 mg SBAC in 150 mL solution; 24 h contact time) for each HOC. In the batch tests, the adsorption capacity was generally negatively correlated to the compounds' hydrophobicity (log K ow ) and positively associated with decreasing molecule size, suggesting that molecular sieving limited adsorption. However, in repeated adsorption tests, where competition between HOCs was more likely to occur, adsorbed pollutant loads exhibited strong positive correlation with log K ow . Sewage sludge as a carbon source for activated carbon has great potential as a sustainable alternative for sludge waste management practices and production of a high-capacity adsorption material. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    Directory of Open Access Journals (Sweden)

    Song Bao

    Full Text Available Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1. The hydrogel also exhibited higher separation selectivity to Pb(2+ than Cu(2+. The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.

  15. Effect of activated carbon in PSF-PEI-Ag symmetric membrane

    Directory of Open Access Journals (Sweden)

    Said Khairul Anwar Mohamad

    2017-01-01

    Full Text Available Polysulfone (Psf composite membrane consist of activated carbon, polyethyleneimine and silver nitrate was prepared by phase inversion. The activated carbon (AC act as adsorbent to adsorb heavy metal present in synthetic waste water while polysulfone membrane act as support. Phase inversion was carried out on different composition of activated carbon from 0 to 0.9% while other component are remain constant. The surface morphology of composite membrane was characterized by scanning electron microscopy (SEM while heavy metal absorption was quantified by atomic absorption spectrometer (AAS. The SEM image show symmetric membrane matrix with sponge structure. The composite membrane with 0.9wt% AC has the highest water flux as well as removal of heavy metal (chromium, lead, silver and cadmium compare to composite membrane with 0.3wt% AC and 0.5wt% AC. The percentage of heavy metal reduction by composite membrane 0.9wt% AC was 35% cadmium, 19% chromium, 16% silver and 2% lead. The result indicated that the introduction of 0.9wt% AC indeed plays an important role towards enhancing the adsorption of heavy metal in water.

  16. Flame Retardancy Effects of Graphene Nanoplatelet/Carbon Nanotube Hybrid Membranes on Carbon Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Dongxian Zhuo

    2013-01-01

    Full Text Available Carbon nanotube/graphene nanoplatelet (MWCNT/GNP hybrid membranes with lower liquid permeability and better barrier effect compared to MWCNT membranes were successfully synthesized by vacuum filtering. Their morphologies, water permeability, and pore structures were characterized by a scanning electron microscope (SEM and nitrogen adsorption isotherms. Furthermore, MWCNT/GNP membranes were used to improve the flame retardancy of carbon fiber reinforced polymer (CFRP composites, and the influence of weight percentage of GNPs on the permeability and flame retardancy of MWCNT/GNP membranes was systematically investigated. Results show that incorporation of MWCNT/GNP membranes on CFRP composite plates can remarkably improve the flame retardancy of CFRP composites. Specifically, the incorporation of hierarchical MWCNT/GNP membrane with 7.5 wt% of GNP displays a 35% reduction in the peak heat release rate (PHRR for a CFRP composite plate with the epoxy as matrix and a 11% reduction in PHRR compared with the incorporation of MWCNT membrane only. A synergistic flame retarding mechanism is suggested to be attributed to these results, which includes controlling the pore size and penetrative network structure.

  17. Influence of activated carbon characteristics on toluene and hexane adsorption: Application of surface response methodology

    Science.gov (United States)

    Izquierdo, Mª Teresa; de Yuso, Alicia Martínez; Valenciano, Raquel; Rubio, Begoña; Pino, Mª Rosa

    2013-01-01

    The objective of this study was to evaluate the adsorption capacity of toluene and hexane over activated carbons prepared according an experimental design, considering as variables the activation temperature, the impregnation ratio and the activation time. The response surface methodology was applied to optimize the adsorption capacity of the carbons regarding the preparation conditions that determine the physicochemical characteristics of the activated carbons. The methodology of preparation produced activated carbons with surface areas and micropore volumes as high as 1128 m2/g and 0.52 cm3/g, respectively. Moreover, the activated carbons exhibit mesoporosity, ranging from 64.6% to 89.1% the percentage of microporosity. The surface chemistry was characterized by TPD, FTIR and acid-base titration obtaining different values of surface groups from the different techniques because the limitation of each technique, but obtaining similar trends for the activated carbons studied. The exhaustive characterization of the activated carbons allows to state that the measured surface area does not explain the adsorption capacity for either toluene or n-hexane. On the other hand, the surface chemistry does not explain the adsorption results either. A compromise between physical and chemical characteristics can be obtained from the appropriate activation conditions, and the response surface methodology gives the optimal activated carbon to maximize adsorption capacity. Low activation temperature, intermediate impregnation ratio lead to high toluene and n-hexane adsorption capacities depending on the activation time, which a determining factor to maximize toluene adsorption.

  18. The adsorption of Benzene-Ethylene Dichloride Mixtures on Activated Carbon

    Science.gov (United States)

    Miao, T.; Tang, H. M.; Cheng, Z. X.

    2018-02-01

    The single component adsorption of benzene and ethylene dichloride and also the adsorption of binary mixtures of benzene and ethylene dichloride have been studied in a small fixed isothermal bed containing activated carbon (AC). Results indicate that an empirical Langmuir isotherm fits the experimental data for single components. An extended form of the empirical Langmuir isotherm, in which the parameters are obtained from single component data, satisfactorily describes the adsorption of binary mixtures. Breakthrough curves of both components could be predicted with good precision studied. This paper analyses the adsorption behaviour of a mixture of VOCs (benzene–ethylene dichloride) on AC, due to the lack of information regarding the adsorption of mixtures.

  19. Ab initio study of aspirin adsorption on single-walled carbon and carbon nitride nanotubes

    Science.gov (United States)

    Lee, Yongju; Kwon, Dae-Gyeon; Kim, Gunn; Kwon, Young-Kyun

    We use ab intio density functional theory to investigate the adsorption properties of acetylsalicylic acid or aspirin on a (10, 0) carbon nanotube (CNT) and a (8, 0) triazine-based graphitic carbon nitride nanotube (CNNT). It is found that an aspirin molecule binds stronger to the CNNT with its adsorption energy of 0.67 eV than to the CNT with 0.51 eV. The stronger adsorption energy on the CNNT is ascribed to the high reactivity of its N atoms with high electron affinity. The CNNT exhibits local electric dipole moments, which cause strong charge redistribution in the aspirin molecule adsorbed on the CNNT than on the CNT. We also explore the influence of an external electric field on the adsorption properties of aspirin on these nanotubes by examining the modifications in their electronic band structures, partial densities of states, and charge distributions. It is found that an electric field applied along a particular direction induces aspirin molecular states in the in-gap region of the CNNT implying a potential application of aspirin detection.

  20. Selective adsorption of refractory sulfur species on active carbons and carbon based CoMo catalyst.

    Science.gov (United States)

    Farag, Hamdy

    2007-03-01

    Adsorption technique could be a reliable alternative in removing to a certain remarkable extent the sulfur species from the feedstock of petroleum oil. The performance of various carbons on adsorption of model sulfur compounds in a simulated feed solution and the sulfur containing compounds in the real gas oil was evaluated. The adsorption experiments have been carried out in a batch scale at ambient temperature and under the atmospheric pressure. In general, the most refractory sulfur compounds in the hydrotreatment reactions were selectively removed and adsorbed. It was found that the adsorbents affinities to dibenzothiophene and 4,6-dimethyldibenzothiophene were much more favored and pronounced than the aromatic matrices like fluorene, 1-methylnaphthalene and 9-methylanthracene. Among the sulfur species, 4,6-dimethyldibenzothiophene was the highest to be removed in terms of both selectivity and capacity over all the present adsorbents. The studied adsorbents showed significant capacities for the polyaromatic thiophenes. The electronic characteristics seem to play a certain role in such behavior. Regeneration of the used adsorbent was successfully attained either by washing it with toluene or by the release of the adsorbates through heat treatment. A suggested adsorptive removal process of sulfur compounds from petroleum distillate over carbon supported CoMo catalyst was discussed.

  1. Ionic liquid-impregnated activated carbon for biohydrogen purification in an adsorption unit

    Science.gov (United States)

    Yusuf, N. Y.; Masdar, M. S.; Isahak, W. N. R. W.; Nordin, D.; Husaini, T.; Majlan, E. H.; Rejab, S. A. M.; Chew, C. L.

    2017-06-01

    Biological methods for hydrogen production (biohydrogen) are known as energy intensive and can be operated at ambient temperature and pressure; however, consecutive productions such as purification and separation processes still remain challenging in the industry. Various techniques are used to purify and separate hydrogen. These techniques include the use of sorbents/solvents, membranes and cryogenic distillation. In this study, carbon dioxide (CO2) was purified and separated from biohydrogen to produce high purity hydrogen gas. CO2 capture was studied using the activated carbon (AC) modified with the ionic liquid (IL) choline chloride as adsorbent. The physical and chemical properties of the adsorbents were characterized through XRD, FTIR, SEM-EDX, TGA, and BET analyses. The effects of IL loading, flow rate, temperature, and gas mixture were also investigated based on the absorption and desorption of CO2. The CO2 level in the biohydrogen composition was analyzed using a CO2 gas analyzer. The SEM image indicated that the IL homogeneously covered the AC surface. High IL dispersion inlet enhanced the capability of the adsorbent to capture CO2 gas. The thermal stability and presence of the functionalized group of ILs on AC were analyzed by TGA and FTIR techniques, respectively. CO2 adsorption experiments were conducted using a 1 L adsorber unit. Hence, adsorption technologies exhibit potential for biohydrogen purification and mainly affected by adsorbent ability and operating parameters. This research presents an improved biohydrogen technique based on adsorption technology with novel adsorbents. Two different types of commercial CO2 adsorbents were used in the experiment. Results show that the IL/AC exhibited properties suitable for CO2 adsorption. The IL/AC sample presented a high CO2 uptake of 30 wt. % IL when treated at 30 °C for 6 h under a flow rate of 1 L/min. The presence of IL increased the selectivity of CO2 removal during the adsorption process. This IL

  2. Iron-complexed adsorptive membrane for As(V) species in water

    International Nuclear Information System (INIS)

    Shinde, Rakesh N.; Das, Sadananda; Acharya, R.; Rajurkar, N.S.; Pandey, Ashok K.

    2012-01-01

    Highlights: ► Functionalized membrane was prepared by graft polymerization in host membrane. ► Fe 3+ ions fixed in membrane made it selective for As(V) ions. ► As(V) preconcentrated selectively in membrane samples was quantified by INAA. ► As(V) in ground water sample was easily quantified in 2–3 ppb using membrane. ► Total inorganic arsenic could be quantified by oxidation of As(III) to As(V). - Abstract: Selective preconcentration of a target analyte in the solid phase is an effective route not only to enhance detection limit of the conventional analytical method but also for elimination of interfering matrix. An adsorptive membrane was developed for selective preconcentration and quantification of ultra-trace (ppb) amounts of As(V) present in a variety of aqueous samples. The precursor membrane was prepared by UV-initiator induced graft polymerization of sulphate and phosphate bearing monomers (1:1 mol proportion) in pores of the host microporous poly(propylene) membrane. Fe 3+ ions were loaded in the precursor membrane to make it selective for As(V) ions. The presence of phosphate functional groups prevent leaching of Fe 3+ ions from the membrane when it comes in contact with solution like seawater having high ionic strength. The optimized membrane was characterized in terms of its physical structure, chemical structure and experimental conditions affecting As(V) uptake in the membrane. The possibility of quantifying total preconcentration of As content was also explored by converting As(III) to As(V). To quantify As(V), the membrane samples were subjected to instrumental neutron activation analysis (INAA). The studies carried in the present work showed that quantification of inorganic arsenic species in natural water samples is easily possible in 2–3 ppb concentration range.

  3. Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents

    Science.gov (United States)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, the current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is nonregenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture.

  4. Adsorption of Benzaldehyde on Granular Activated Carbon: Kinetics, Equilibrium, and Thermodynamic

    OpenAIRE

    Rajoriya, R.K.; Prasad, B.; Mishra, I.M.; Wasewar, K.L.

    2007-01-01

    Adsorption isotherms of benzaldehyde from aqueous solutions onto granular activated carbon have been determined and studied the effect of dosage of granular activated carbon, contact time, and temperature on adsorption. Optimum conditions for benzaldehyde removal were found adsorbent dose 4 g l–1 of solution and equilibrium time t 4 h. Percent removal of benzaldehyde increases with the increase in adsorbent dose for activated carbon, however, it decreases with increase in benzaldehyde m...

  5. Adsorption characteristics of Fe(III) and Fe(III)-NTA complex on granular activated carbon.

    Science.gov (United States)

    Kim, D S

    2004-01-02

    The adsorption of Fe(3+) ion on granular activated carbon has been studied in kinetic and equilibrium conditions taking into account the adsorbate concentration, temperature and solution pH as major influential factors. In addition, the effect of nitrilotriacetic acid on adsorption reaction as a complexing agent has been examined. Kinetic studies showed that the adsorption rate was increased as the initial Fe(3+) concentration was raised. The adsorption reaction was estimated to be first-order at room temperature. The adsorption rate and equilibrium adsorption of Fe(3+) increased as the temperature rose. The activation energy for adsorption was approximately 2.23 kJ mol(-1), which implied that Fe(3+) mainly physically adsorbed on activated carbon. Coexistence of nitrilotriacetic acid with Fe(3+) resulted in a decrease of equilibrium adsorption and the extent of decrease was proportional to the concentration of nitrilotriacetic acid. In the presence of nitrilotriacetic acid, the adsorbability of Fe(3+) decreased with pH. However, the trend was reversed in the absence of nitrilotriacetic acid. When activated carbon was swelled by acetic acid, the specific surface area was increased and maximum swelling was achieved at approximately 48 h of swelling time. Thermodynamic parameters such as DeltaG(o), DeltaH(o) and DeltaS(o) for adsorption reaction were estimated based on equilibrium data and in connection with these results the thermodynamic aspects of adsorption reaction were discussed.

  6. Adsorption of Geosmin and MIB on Activated Carbon Fibers-Single and Binary Solute System

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, Rangesh; Sorial, George A., E-mail: george.sorial@uc.ed [University of Cincinnati, Department of Civil and Environmental Engineering (United States)

    2009-08-15

    The adsorption of two taste- and odor-causing compounds, namely MIB (2-methyl isoborneol-C{sub 11}H{sub 20}O) and geosmin (C{sub 12}H{sub 22}O) on activated carbon was investigated in this study. The impact of adsorbent pore size distribution on adsorption of MIB and geosmin was evaluated through single solute and multicomponent adsorption of these compounds on three types of activated carbon fibers (ACFs) and one granular activated carbon (GAC). The ACFs (ACC-15, ACC-20, and ACC-25) with different degrees of activation had narrow pore size distributions and specific critical pore diameters whereas the GAC (F-400) had a wider pore size distribution and lesser microporosity. The effect of the presence of natural organic matter (NOM) on MIB and geosmin adsorption was also studied for both the single solute and binary systems. The Myers equation was used to evaluate the single solute isotherms as it converges to Henry's law at low coverage and also serves as an input for predicting multicomponent adsorption. The single solute adsorption isotherms fit the Myers equation well and pore size distribution significantly influenced adsorption on the ACFs and GAC. The ideal adsorbed solute theory (IAST), which is a well-established thermodynamic model for multicomponent adsorption, was used to predict the binary adsorption of MIB and geosmin. The IAST predicted well the binary adsorption on the ACFs and GAC. Binary adsorption isotherms were also conducted in the presence of oxygen (oxic) and absence of oxygen (anoxic). There were no significant differences in the binary isotherm between the oxic and anoxic conditions, indicating that adsorption was purely through physical adsorption and no oligomerization was taking place. Binary adsorptions for the four adsorbents were also conducted in the presence of humic acid to determine the effect of NOM and to compare with IAST predictions. The presence of NOM interestingly resulted in deviation from IAST behavior in case of two

  7. Direct measurements of adsorption heats of hydrogen on nano-porous carbons

    International Nuclear Information System (INIS)

    Akihiko, Matsumoto; Kazumasa, Yamamoto; Tomoyuki, Miyata

    2005-01-01

    Since a exciting report of hydrogen storage in single-walled carbon nano-tubes by Dillon and his colleagues [1], nano-porous carbon materials, such as carbon nano-tubes, carbon nano-horns and micro-porous activated carbon, have attracted considerable attention as hydrogen storage materials. Adsorption plays a predominating role in the hydrogen storage process on solid surfaces. The adsorption is a spontaneous process, which is caused by interaction between gas molecules and surface, hence, it is always exothermic process and observed as adsorption heats. For this reason, direct measurement of the adsorption heats by adsorption microcalorimetry would provide quantitative information on the strength of adsorption interaction and the adsorption mechanism. However, the adsorption amounts of hydrogen on carbon materials are far less than those of condensable vapors near room temperature due to low critical temperature of hydrogen (33.2 K), therefore, the adsorption heats can not be determined accurately at conventional measurement conditions near room temperature and the atmospheric pressure. This contribution reports the calorimetric characterization of hydrogen adsorption on nano-porous carbon materials at low temperature and high-pressure conditions. The high-pressure adsorption apparatus consists of a volumetric adsorption line connected to a twin-conduction type microcalorimeter. Activated carbon fibers (ACF, Ad'all Co.) of different micropore sizes (Table 1) were used as model adsorbents. Each ACF has slit-shaped micropores of uniform size [2]. The adsorption isotherms and differential heats of adsorption at high-pressure region from 0 to 10 MPa were simultaneously measured at isothermal condition from 203 to 298 K. The adsorption isotherms on ACF were of Henry type regardless of adsorption temperature and pore width; the uptakes increased linearly with equilibrium pressure. The adsorption isotherm at lower sorption temperature tended to show higher sorptivity

  8. Direct measurements of adsorption heats of hydrogen on nano-porous carbons

    International Nuclear Information System (INIS)

    Akihiko Matsumoto; Kazumasa Yamamoto; Tomoyuki Miyata

    2005-01-01

    Since a exciting report of hydrogen storage in single-walled carbon nano-tubes by Dillon and his colleagues, nano-porous carbon materials, such as carbon nano-tubes, carbon nano-horns and micro-porous activated carbon, have attracted considerable attention as hydrogen storage materials. Adsorption plays a predominating role in the hydrogen storage process on solid surfaces. The adsorption is a spontaneous process, which is caused by interaction between gas molecules and surface, hence, it is always exothermic process and observed as adsorption heats. For this reason, direct measurement of the adsorption heats by adsorption micro-calorimetry would provide quantitative information on the strength of adsorption interaction and the adsorption mechanism. However, the adsorption amounts of hydrogen on carbon materials are far less than those of condensable vapors near room temperature due to low critical temperature of hydrogen (33.2 K), therefore, the adsorption heats can not be determined accurately at conventional measurement conditions near room temperature and the atmospheric pressure. This contribution reports the calorimetric characterization of hydrogen adsorption on nano-porous carbon materials at low temperature and high-pressure conditions. The high-pressure adsorption apparatus consists of a volumetric adsorption line connected to a twin-conduction type microcalorimeter. Activated carbon fibers (ACF, Ad'all Co.) of different micro-pore sizes (Table 1) were used as model adsorbents. Each ACF has slit-shaped micropores of uniform size. The adsorption isotherms and differential heats of adsorption at high-pressure region from 0 to 10 MPa were simultaneously measured at isothermal condition from 203 to 298 K. The adsorption isotherms on ACF were of Henry type regardless of adsorption temperature and pore width; the uptakes increased linearly with equilibrium pressure. The adsorption isotherm at lower sorption temperature tended to show higher sorptivity. The

  9. Post treatment of antibiotic wastewater by adsorption on activated carbon

    Science.gov (United States)

    Mullai, P.; Rajesh, V.

    2018-02-01

    The most common method of treating industrial wastewater involves biomethanation in anaerobic digesters. This biological treatment process is ineffective in color removal and it requires post-treatment methods. The color is the first contaminant in wastewater which affects the water bodies in several ways. As the anaerobically digested antibiotic wastewater was found with color, an attempt was made to remove color using granulated activated carbon as an adsorbent. Experiments were carried out in batch reactors to find out the color removal efficiency of the wastewater at four different dosages such as 25, 50, 75 and 100 mg of adsorbent material at each of the four different initial concentrations of effluent like 1956, 1450, 1251 and 1040 mg COD/L. The steady state values of color removal efficiencies were 96.6, 97.64, 98.64 and 99.63%, respectively, using 100 mg of activated carbon under shaking condition at the end of the 120th min. The effect of contact time on the percentage of color removal was also studied. It was observed that the adsorption of effluent obtained equilibrium at 120 minutes. The equilibrium data fitted well with the Langmuir and Freundlich isotherms.

  10. Using of Grafted Membranes in Adsorption of Certain Radioelements From Liquid Waste

    International Nuclear Information System (INIS)

    Hegazy, E.A.; Maziad, A.N.; Sayed, S.M.

    2001-01-01

    Applications of the grafted ion exchange membrane for the separation of radioactive ions from the radioactive waste have been studied. Prepared grafted membranes of low density polyethylene LDPE grafted with acrylonitrile A N are used for the chelation or adsorption of the low level radioactive waste such as 152+154 Eu, 60 Co and 137 Cs from their waste solutions. Some properties of the prepared grafted films such as swelling behaviour, electric conductivity and mechanical properties were investigated. Thermal properties of the prepared materials were studied using thermogravimetric analysis and differential scanning calorimeter. The selectivity of the grafted membranes towards different radioactive waste was also studied. On the basis of these investigations the applicability of the prepared membranes is determined and discussed. 152+1454 Eu can be separated from the waste solution containing 137 Cs and 60 Co

  11. Adsorption and binding dynamics of graphene-supported phospholipid membranes using the QCM-D technique.

    Science.gov (United States)

    Meléndrez, D; Jowitt, T; Iliut, M; Verre, A F; Goodwin, S; Vijayaraghavan, A

    2018-02-01

    We report on the adsorption dynamics of phospholipid membranes on graphene-coated substrates using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. We compare the lipid vesicle interaction and membrane formation on gold and silicon dioxide QCM crystal surfaces with their graphene oxide (GO) and reduced (r)GO coated counterparts, and report on the different lipid structures obtained. We establish graphene derivative coatings as support surfaces with tuneable hydrophobicity for the formation of controllable lipid structures. One structure of interest formed is lipid monolayer membranes which were formed on rGO, which are otherwise challenging to produce. We also demonstrate and monitor biotin-avidin binding on such a membrane, which will then serve as a platform for a wide range of biosensing applications. The QCM-D technique could be extended to both fundamental studies and applications of other covalent and non-covalent interactions in 2-dimensional materials.

  12. [Adsorption and desorption of dyes by waste-polymer-derived activated carbons].

    Science.gov (United States)

    Lian, Fei; Liu, Chang; Li, Guo-Guang; Liu, Yi-Fu; Li, Yong; Zhu, Ling-Yan

    2012-01-01

    Mesoporous activated carbons with high surface area were prepared from three waste polymers, i. e., tire rubber, polyvinyl chloride (PVC) and polyethyleneterephtalate (PET), by KOH activation. The adsorption/desorption characteristics of dyes (methylene blue and methyl orange) on the carbons were studied. The effects of pH, ionic strength and surface surfactants in the solution on the dye adsorption were also investigated. The results indicated that the carbons derived from PVC and PET exhibited high surface area of 2 666 and 2 831 m2 x g(-1). Their mesopore volume were as high as 1.06 and 1.30 cm3 g(-1), respectively. 98.5% and 97.0% of methylene blue and methyl orange were removed in 15 min by PVC carbon, and that of 99.5% and 95.0% for PET carbon. The Langmuir maximum adsorption capacity to these dyes was more than 2 mmol x g(-1), much higher than that of commercial activated carbon F400. Compared with Freundlich model, the adsorption data was fitted better by Langmiur model, indicating monolayer coverage on the carbons. The adsorption was highly dependent on solution pH, ionic strength and concentration of surface surfactants. The activated carbons exhibited higher adsorption to methylene blue than that of methyl orange, and it was very hard for both of the dyes to be desorbed. The observation in this study demonstrated that activated carbons derived from polymer waste could be effective adsorbents for the treatment of wastewater with dyes.

  13. Improving carbon tolerance of Ni-YSZ catalytic porous membrane by palladium addition for low temperature steam methane reforming

    Science.gov (United States)

    Lee, Sang Moon; Won, Jong Min; Kim, Geo Jong; Lee, Seung Hyun; Kim, Sung Su; Hong, Sung Chang

    2017-10-01

    Palladium was added on the Ni-YSZ catalytic porous membrane by wet impregnation and electroless plating methods. Its surface morphology characteristics and carbon deposition properties for the low temperature steam methane reforming were investigated. The addition of palladium could obviously be enhanced the catalytic activity as well as carbon tolerance of the Ni-YSZ porous membrane. The porous membranes were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), CH4 temperature-programmed reduction (CH4-TPR), and O2 temperature-programmed oxidation (O2-TPO). It was found that the Pd-Ni-YSZ catalytic porous membrane showed the superior stability as well as the deposition of carbon on the surface during carbon dissociation adsorption at 650 °C was also suppressed.

  14. Gas Phase Transport, Adsorption and Surface Diffusion in Porous Glass Membrane

    Czech Academy of Sciences Publication Activity Database

    Yang, J.; Čermáková, Jiřina; Uchytil, Petr; Hamel, Ch.; Seidel-Morgenstern, A.

    2005-01-01

    Roč. 104, 2-4 (2005), s. 344-351 ISSN 0920-5861. [International Conference on Catalysis in Membrane Reactors /6./. Lahnstein, 06.07.2004-09.07.2004] R&D Projects: GA AV ČR(CZ) IAA4072402 Institutional research plan: CEZ:AV0Z40720504 Keywords : gas phase transport * vycor glass * adsorption Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.365, year: 2005

  15. Synthesis of Mesoporous Carbons from Date Pits for the Adsorption of Large Molecular Weight Micropollutants in Wastewater

    KAUST Repository

    Al Jeffrey, Ahmed

    2013-07-01

    Efficient reuse of waste water requires removal of micro-pollutants from waste water streams by affordable and sustainable methods. Activated carbon is considered a powerful adsorbent due to its high surface area and low cost of treatment, compared to other expensive methods such as membrane filtration. Producing activated carbon with larger mesoporosity (>2nm) is of particular interest in industry in the removal of larger molecular sized pollutants. This study reports the synthesis of mesoporous activated carbons from a nonsoluble biomass precursor (date-pits) along with chemical activation using ZnCl2. Thus, produced activated carbon showed high surface area and large mesopore volume up to 1571 m2/g and 2.00 cm3/g respectively. In addition, the pore size of the product was as high as 9.30 nm. As a method of verification, HRTEM (Highresolution transmission electron microscopy) was used to directly authenticate the pore size of the synthesized activated carbons. Tannic acid and atrazine were used as model waste water pollutants and the adsorption capability of the produced activated carbon for these pollutants were evaluated and compared to a commercial mesoporous carbon: G60 from Norit. The results showed that the sorption capacity of produced activated carbon for tannic acid was 2 times that of G60 while the sorption capacity of produced activated carbon for atrazine was lower than that of G60. The activated carbon was also evaluated for adsorption of real secondary effluent municipal wastewater and the results suggest that the produced activated carbon was able to sorb a greater amount of biopolymers than G60. These results demonstrate that the thus-produced activated carbon may be a promising sorbent for waste water treatment.

  16. Development of adsorptive membranes by confinement of activated biochar into electrospun nanofibers

    Directory of Open Access Journals (Sweden)

    Mehrdad Taheran

    2016-11-01

    Full Text Available Adsorptive membranes have many applications in removal of contaminants, such as heavy metals and organic contaminants from water. Recently, increasing concentrations of pharmaceutically active compounds, especially antibiotics, such as chlortetracycline in water and wastewater sources has raised concerns about their potentially adverse impacts on environment and human health. In this study, a series of polyacrylonitrile (PAN/activated biochar nanofibrous membranes (NFMs with different loadings of biochar (0–2%, w/w were fabricated using electrospinning. The morphology and structure of fabricated membranes was investigated by scanning electron microscopy, Fourier transform infrared and thermogravimetric analysis. The results showed that at 1.5% of biochar loading, the surface area reached the maximum value of 12.4 m2/g and beyond this loading value, agglomeration of particles inhibited fine interaction with nanofibrous matrix. Also, the adsorption tests using chlortetracycline showed that, under environmentally relevant concentrations, the fabricated adsorptive NFMs had a potential for removal of these types of emerging contaminants from water and wastewaters.

  17. Studying the role of common membrane surface functionalities on adsorption and cleaning of organic foulants using QCM-D.

    Science.gov (United States)

    Contreras, Alison E; Steiner, Zvi; Miao, Jing; Kasher, Roni; Li, Qilin

    2011-08-01

    Adsorption of organic foulants on nanofiltration (NF) and reverse osmosis (RO) membrane surfaces strongly affects subsequent fouling behavior by modifying the membrane surface. In this study, impact on organic foulant adsorption of specific chemistries including those in commercial thin-film composite membranes was investigated using self-assembled monolayers with seven different ending chemical functionalities (-CH(3), -O-phenyl, -NH(2), ethylene-glycol, -COOH, -CONH(2), and -OH). Adsorption and cleaning of protein (bovine serum albumin) and polysaccharide (sodium alginate) model foulants in two solution conditions were measured using quartz crystal microbalance with dissipation monitoring, and were found to strongly depend on surface functionality. Alginate adsorption correlated with surface hydrophobicity as measured by water contact angle in air; however, adsorption of BSA on hydrophilic -COOH, -NH(2), and -CONH(2) surfaces was high and dominated by hydrogen bond formation and electrostatic attraction. Adsorption of both BSA and alginate was the fastest on -COOH, and adsorption on -NH(2) and -CONH(2) was difficult to remove by surfactant cleaning. BSA adsorption kinetics was shown to be markedly faster than that of alginate, suggesting its importance in the formation of the conditioning layer. Surface modification to render -OH or ethylene-glycol functionalities are expected to reduce membrane fouling.

  18. Dye removal from wastewater using activated carbon developed from sawdust: adsorption equilibrium and kinetics.

    Science.gov (United States)

    Malik, P K

    2004-09-10

    Mahogany sawdust was used to develop an effective carbon adsorbent. This adsorbent was employed for the removal of direct dyes from spent textile dyeing wastewater. The experimental data were analysed by the Langmuir and Freundlich models of adsorption. Equilibrium data fitted well with the Langmuir model. The rates of adsorption were found to conform to the pseudo-second-order kinetics with good correlation. The equilibrium adsorption capacity of the sawdust carbon was determined with the Langmuir equation as well as the pseudo-second-order rate equation and found to be >300 mg dye per gram of the adsorbent. The most ideal pH for adsorption of direct dyes onto sawdust carbon was found to be 3 and below. The results indicate that the Mahogany sawdust carbon could be employed as a low cost alternative to commercial activated carbon in the removal of dyes from wastewater.

  19. Chemisorption of estrone in nylon microfiltration membranes: Adsorption mechanism and potential use for estrone removal from water.

    Science.gov (United States)

    Han, Jie; Qiu, Wei; Hu, Jiangyong; Gao, Wei

    2012-03-01

    Estrone is a representative steroid estrogen contaminant that has been detected in effluents from sewage treatment facilities, as well as in surface and ground waters. Our study shows that estrone can be readily removed from water via a unique chemisorption mechanism using nylon microfiltration membranes. Experiments on a laboratory in-line filtration system showed instant removal of estrone from 200 μg/l aqueous solutions by 0.45-μm nylon membranes (ca. 35 L per m(2) membrane). Comparisons with 0.45-μm PVDF, PTFE and glass microfiber membranes suggested that the significant estrone adsorption in nylon membrane should be predominately driven by a different mechanism rather than common physical adsorption. Fourier transform infrared spectroscopy study on nylon membranes and a model compound, N-methylacetamide, showed that the significant adsorption originated from the hydrogen bonding between terminal -OH groups on estrone molecules and nucleophile -C=O groups in amide groups of nylon 6,6. The saturated nylon membrane showed very low leachability in ambient water, while it could be effectively regenerated in alkaline or ethanol solutions. Preliminary reusability study showed that the membrane maintained a consistent adsorption capacity for estrone during ten cycles of reuse. The chemisorption-based polymeric adsorption may provide a new alternative approach for removing estrone and potentially other trace organic contaminants from water. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Carbon and TiO{sub 2} synergistic effect on methylene blue adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Simonetti, Evelyn Alves Nunes, E-mail: evelynalvesnunes@yahoo.com.br; Simone Cividanes, Luciana de; Campos, Tiago Moreira Bastos; Rossi Canuto de Menezes, Beatriz; Brito, Felipe Sales; Thim, Gilmar Patrocínio

    2016-07-01

    Due to its high efficiency, low cost and a simple operation, the adsorption process is an important and widely used technique for industrial wastewater treatment. Recent studies on the removal of artificial dyes by adsorption include a large number of adsorbents, such as: activated carbon, silicates, carbon nanotube, graphene, fibers, titanates and doped titanates. The carbon insertion in the TiO{sub 2} structure promotes a synergistic effect on the adsorbent composite, improving the adsorption and the charge-transfer efficiency rates. However, there are few studies regarding the adsorption capacity of TiO{sub 2}/Carbon composites with the carbon concentration. This study evaluates the effect of carbon (resorcinol/formaldehyde) insertion on TiO{sub 2} structure through the adsorption process. Adsorbents were prepared by varying the carbon weight percentages using the sol-gel method. The physicochemical properties of the catalysts prepared, such as crystallinity, particle size, surface morphology, specific surface area and pore volume were investigated. The kinetic study, adsorption isotherm, pH effect and thermodynamic study were examined in batch experiments using methylene blue as organic molecule. In addition, the effect of carbon phase on the adsorption capacity of TiO{sub 2}-carbon composite was deeply investigated. SEM micrographs showed that TiO{sub 2} phase grows along the carbon phase and FT-IR results showed the presence of Ti−O−C chemical bonding. The experiments indicate that the carbon phase acted as a nucleation agent for the growth of TiO{sub 2} during the sol-gel step, with a TiO{sub 2} structure suitable for blue methylene adsorption, resulting in a material with large surface area and slit-like or wedge-shaped pores. Further experiments will show the best carbon concentration for methylene blue adsorption using a TiO{sub 2} based material. - Highlights: • This article deals with the adsorption of methylene blue onto TiO{sub 2}-Carbon

  1. Ionic Liquid Membranes for Carbon Dioxide Separation

    Energy Technology Data Exchange (ETDEWEB)

    Myers, C.R.; Ilconich, J.B.; Luebke, D.R.; Pennline, H.W.

    2008-07-12

    Recent scientific studies are rapidly advancing novel technological improvements and engineering developments that demonstrate the ability to minimize, eliminate, or facilitate the removal of various contaminants and green house gas emissions in power generation. The Integrated Gasification Combined Cycle (IGCC) shows promise for carbon dioxide mitigation not only because of its higher efficiency as compared to conventional coal firing plants, but also due to a higher driving force in the form of high partial pressure. One of the novel technological concepts currently being developed and investigated is membranes for carbon dioxide (CO2) separation, due to simplicity and ease of scaling. A challenge in using membranes for CO2 capture in IGCC is the possibility of failure at elevated temperatures or pressures. Our earlier research studies examined the use of ionic liquids on various supports for CO2 separation over the temperature range, 37°C-300°C. The ionic liquid, 1-hexyl-3methylimidazolium Bis(trifluoromethylsulfonyl)imide, ([hmim][Tf2N]), was chosen for our initial studies with the following supports: polysulfone (PSF), poly(ether sulfone) (PES), and cross-linked nylon. The PSF and PES supports had similar performance at room temperature, but increasing temperature caused the supported membranes to fail. The ionic liquid with the PES support greatly affected the glass transition temperature, while with the PSF, the glass transition temperature was only slightly depressed. The cross-linked nylon support maintained performance without degradation over the temperature range 37-300°C with respect to its permeability and selectivity. However, while the cross-linked nylon support was able to withstand temperatures, the permeability continued to increase and the selectivity decreased with increasing temperature. Our studies indicated that further testing should examine the use of other ionic liquids, including those that form chemical complexes with CO2 based on

  2. Characteristics and adsorption study of the activated carbon derived from municipal sewage sludge.

    Science.gov (United States)

    Guo, Tiecheng; Yao, Sicong; Chen, Hengli; Yu, Xin; Wang, Meicheng; Chen, Yao

    2017-10-01

    Sewage sludge-based activated carbon is proved to be an efficient and low-cost adsorbent in treatment of various industrial wastewaters. The produced carbon had a well-developed pore structure and relatively low Brunauer-Emmett-Teller (BET) surface area. Adsorptive capacity of typical pollutants, i.e. copper Cu(II) and methylene blue (MB) on the carbon was studied. Adsorptions were affected by the initial solution pH, contact time and adsorbent dose. Results showed that adsorption of Cu(II) and MB on the produced carbon could reach equilibrium after 240 min. The average removal rate for Cu(II) on the carbon was high, up to 97% in weak acidic conditions (pH = 4-6) and around 98% for MB in a very wide pH range (pH = 2-12). The adsorption kinetics were well fitted by the pseudo-second order model, and both Langmuir and Freundlich isotherm models could well describe the adsorption process at room temperature. The theoretical maximum adsorption capacities of Cu(II) and MB on sewage sludge-based activated carbon were 114.94 mg/g and 125 mg/g, respectively. Compared with commercial carbon, the sewage sludge-based carbon was more suitable for heavy metal ions' removal than dyes'.

  3. A thermodynamic approach to assess organic solute adsorption onto activated carbon in water

    KAUST Repository

    De Ridder, David J.

    2012-08-01

    In this paper, the hydrophobicity of 13 activated carbons is determined by various methods; water vapour adsorption, immersion calorimetry, and contact angle measurements. The quantity and type of oxygen-containing groups on the activated carbon were measured and related to the methods used to measure hydrophobicity. It was found that the water-activated carbon adsorption strength (based on immersion calorimetry, contact angles) depended on both type and quantity of oxygen-containing groups, while water vapour adsorption depended only on their quantity. Activated carbon hydrophobicity measurements alone could not be related to 1-hexanol and 1,3-dichloropropene adsorption. However, a relationship was found between work of adhesion and adsorption of these solutes. The work of adhesion depends not only on activated carbon-water interaction (carbon hydrophobicity), but also on solute-water (solute hydrophobicity) and activated carbon-solute interactions. Our research shows that the work of adhesion can explain solute adsorption and includes the effect of hydrogen bond formation between solute and activated carbon. © 2012 Elsevier Ltd. All rights reserved.

  4. Characterization of insulin adsorption behavior of dialyzer membranes used in hemodialysis.

    Science.gov (United States)

    Abe, Masanori; Okada, Kazuyoshi; Ikeda, Kazuya; Matsumoto, Shiro; Soma, Masayoshi; Matsumoto, Koichi

    2011-04-01

    Although it has been reported that plasma insulin is removed by hemodialysis (HD), the mechanism for this has not been elucidated. We investigated the mechanism of insulin removal during HD treatment and the characteristics of insulin removal with three high-flux membranes. In our in vivo study, 20 stable diabetic patients on HD were randomly selected for three HD sessions with three different membranes: polysulfone (PS), cellulose triacetate (CTA), and polyester polymer alloy (PEPA). Blood samples were obtained from the blood tubing at the arterial (A) site at the beginning and end of the sixth HD session to investigate insulin reduction in patients. At 1 h after the initiation of dialysis, blood samples were obtained from both the A and venous sites of the dialyzer to investigate the insulin clearance with the different membranes. There was a significant reduction in patients' plasma insulin at each time point with each of the three membranes. The insulin clearance with the PS membrane was significantly higher than that with the CTA and PEPA membranes. Although no difference was observed in the plasma insulin reduction rate between the three membranes in the total subject group, there was a significantly higher reduction rate with the PS membrane in insulin-dependent diabetes mellitus subjects. The clearance of insulin in in vitro tests was significantly higher with the PS and PEPA membranes than with the CTA membrane in both new and clinically used dialyzers. Insulin was not detected in the dialysate or ultrafiltration fluids in either the in vivo or in vitro studies. The mechanism of plasma insulin clearance by HD is mainly by adsorption, and the amount of insulin adsorbed differed depending on the dialyzer membrane used. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  5. Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review

    Directory of Open Access Journals (Sweden)

    W.D.P Rengga

    2012-11-01

    Full Text Available Gas storage is a technology developed with an adsorptive storage method, in which gases are stored as adsorbed components on the certain adsorbent. Formaldehyde is one of the major indoor gaseous pollutants. Depending on its concentration, formaldehyde may cause minor disorder symptoms to a serious injury. Some of the successful applications of technology for the removal of formaldehyde have been reported. However, this paper presents an overview of several studies on the elimination of formaldehyde that has been done by adsorption method because of its simplicity. The adsorption method does not require high energy and the adsorbent used can be obtained from inexpensive materials. Most researchers used activated carbon as an adsorbent for removal of formaldehyde because of its high adsorption capacity. Activated carbons can be produced from many materials such as coals, woods, or agricultural waste. Some of them were prepared by specific activation methods to improve the surface area. Some researchers also used modified activated carbon by adding specific additive to improve its performance in attracting formaldehyde molecules. Proposed modification methods on activation and additive impregnated carbon are thus discussed in this paper for future development and improvement of formaldehyde adsorption on activated carbon. Specifically, a waste agricultural product is chosen for activated carbon raw material because it is renewable and gives an added value to the materials. The study indicates that the performance of the adsorption of formaldehyde might be improved by using modified activated carbon. Bamboo seems to be the most appropriate raw materials to produce activated carbon combined with applying chemical activation method and addition of metal oxidative catalysts such as Cu or Ag in nano size particles. Bamboo activated carbon can be developed in addition to the capture of formaldehyde as well as the storage of adsorptive hydrogen gas that

  6. Application and characterization of electroactive membranes based on carbon nanotubes and zerovalent iron nanoparticles.

    Science.gov (United States)

    Yanez H, Jorge E; Wang, Zi; Lege, Sascha; Obst, Martin; Roehler, Sebastian; Burkhardt, Claus J; Zwiener, Christian

    2017-01-01

    Carbon nanotube (CNT) membranes were produced from multi-walled CNTs by a filtration technique and used for the removal of the betablocker metoprolol by adsorptive and reactive processes. The reactivity of CNT membranes was enhanced by nanoparticulate zero-valent iron (NZVI) which was deposited on the CNT membranes by pulsed voltammetry applying defined number of pulses (Fe-CNT (100) and Fe-CNT (400) membranes). Surface analysis with SEM showed iron nanoparticle sizes between 19 and 425 nm. Pore size distribution for the different membranes was determined by capillary flow porometry (Galwick fluid). Pore size distribution for all membranes was similar (40 nm), which resulted in a water permeability typical for microfiltration membranes. Metoprolol was removed by the CNT membrane only by sorption, whereas the Fe-CNT membrane revealed also metoprolol degradation due to Fenton type reactions. Further application of electrochemical potentials on both the CNT and the Fe-CNT membranes improved the removal efficiencies to 74% for CNT membranes at 1 V and to 97% for Fe-CNT (400) membranes at 1 V. Seven transformation products have been identified for metoprolol by high-resolution mass spectrometry when electrochemical degradation was performed with CNT and Fe-CNT membranes. Additionally, two of the identified transformation products (TPs) were also observed for Fe-CNT membranes without the application of electrochemical potential. However, only 10% of the degraded metoprolol could be explained by the formation of TPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Preparation of mesoporous poly (acrylic acid)/SiO2 composite nanofiber membranes having adsorption capacity for indigo carmine dye

    Science.gov (United States)

    Xu, Ran; Jia, Min; Li, Fengting; Wang, Hongtao; Zhang, Bingru; Qiao, Junlian

    2012-03-01

    Mesoporous poly (acrylic acid)/SiO2 (PAA/SiO2) composite nanofiber membranes functionalized with mercapto groups were fabricated by a sol-gel electrospinning method, and their adsorption capacity for indigo carmine was investigated. The membranes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray powder diffraction (XRD), and nitrogen adsorption-desorption measurement. SEM and TEM observation results showed that the PAA/SiO2 fibers had diameters between 400-800 nm and mesopores with an average pore size of 3.88 nm. The specific surface area of the mesoporous nanofiber membranes was 514.89 m2/g. The characteristic peaks for mercapto group vibration in FTIR and Raman spectra demonstrated that the mercapto groups have been incorporated into the silica skeleton. The adsorption isotherm data of indigo carmine on the membranes fit well with Redlich-Peterson model, and the maximum adsorption capacity calculated was 523.11 mg/g. It was found that the removal rate of indigo carmine by the membranes reached a maximum of 98% in 90 min and the adsorption kinetics followed a pseudo-second-order model. The high adsorption capacity of PAA/SiO2 nanofiber membrane makes it a promising adsorbent for indigo carmine removal from the wastewater.

  8. Activated carbon derived from carbon residue from biomass gasification and its application for dye adsorption: Kinetics, isotherms and thermodynamic studies.

    Science.gov (United States)

    Maneerung, Thawatchai; Liew, Johan; Dai, Yanjun; Kawi, Sibudjing; Chong, Clive; Wang, Chi-Hwa

    2016-01-01

    In this work, activated carbon (AC) as an effective and low-cost adsorbent was successfully prepared from carbon residue (or char, one of the by-products from woody biomass gasification) via physical activation. The surface area of char was significantly increased from 172.24 to 776.46m(2)/g after steam activation at 900°C. The obtained activated carbons were then employed for the adsorption of dye (Rhodamine B) and it was found that activated carbon obtained from steam activation exhibited the highest adsorption capability, which is mainly attributed to the higher surface area and the abundance of hydroxyl (-OH) and carboxyl (-COOH) groups on the activated carbon surface. Moreover, it was also found that the adsorption capability significantly increased under the basic condition, which can be attributed to the increased electrostatic interaction between the deprotonated (negatively charged) activated carbon and dye molecules. Furthermore, the equilibrium data were fitted into different adsorption isotherms and found to fit well with Langmuir model (indicating that dye molecules form monolayer coverage on activated carbon) with a maximum monolayer adsorption capability of 189.83mg/g, whereas the adsorption kinetics followed the pseudo-second-order kinetics. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Influence of MgO template on carbon dioxide adsorption of cation exchange resin-based nanoporous carbon.

    Science.gov (United States)

    Meng, Long-Yue; Park, Soo-Jin

    2012-01-15

    In this work, porous carbons with well-developed pore structures were directly prepared from a weak acid cation exchange resin (CER) by the carbonization of a mixture with Mg acetate in different ratios. The effect of the Mg acetate-to-CER ratio on the pore structure and CO(2) adsorption capacities of the obtained porous carbons was studied. The textural properties and morphologies of the porous carbons were analyzed via N(2)/77K adsorption/desorption isotherms, SEM, and TEM, respectively. The CO(2) adsorption capacities of the prepared porous carbons were measured at 298 K and 1 bar and 30 bar. By dissolving the MgO template, the porous carbons exhibited high specific surface areas (326-1276 m(2)/g) and high pore volumes (0.258-0.687 cm(3)/g). The CO(2) adsorption capacities of the porous carbons were enhanced to 164.4 mg/g at 1 bar and 1045 mg/g at 30 bar by increasing the Mg acetate-to-CER ratio. This result indicates that CER was one of the carbon precursors to producing the porous structure, as well as for improving the CO(2) adsorption capacities of the carbon species. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  10. Characteristics of an activated carbon monolith for a helium adsorption compressor

    NARCIS (Netherlands)

    Lozano-Castello, D.; Jorda-Beneyto, M.; Cazorla-Amoros, D.; Linares-Solano, A.; Burger, Johannes Faas; ter Brake, Hermanus J.M.; Holland, Herman J.

    2010-01-01

    An activated carbon monolith (ACM) with a high helium adsorption/desorption capacity, high density, low pressure drop, low thermal expansion and good mechanical properties was prepared and applied successfully in a helium adsorption compressor as a part of a 4.5 K sorption cooler. The activated

  11. adsorption on the inside and outside the single-walled carbon ...

    Indian Academy of Sciences (India)

    FAHIMEH SHOJAIE

    2017-12-11

    Dec 11, 2017 ... The adsorption energies, bond order, atomic charge, optical properties, and electrostatic potential of nitrogen molecules of armchair .... the bond length between two carbons in sp2 hybridiza- tion, the diameter of the .... adsorption of N2 molecule(s) on the SWCNT are metallic type (band gap between the.

  12. Interaction of amphipathic α-helical peptides with a lipid membrane: Adsorption and pore formation

    Science.gov (United States)

    Zhdanov, Vladimir P.

    2014-05-01

    Amphipathic α-helical peptides often exhibit antimicrobial or antiviral properties. Adsorption of such peptides at a lipid membrane may result in pore formation. Current phenomenological models of the latter process imply that the peptide-peptide lateral interaction is repulsive and that the conditions for pore formation depend on the difference of the peptide energies at the membrane surface and in a pore. There is, however, experimental evidence that the kinetics of peptide adsorption at small vesicles (about 100 nm diameter) may be cooperative and accordingly the peptide-peptide lateral interaction may be attractive. In addition, the experiments indicate that the peptide-induced pore formation is often observed at the conditions close to those corresponding to pore formation under externally induced tensile stress where the difference of the peptide energies at the membrane surface and in a pore is irrelevant. Here, a model describing both types of peptide-peptide lateral interactions at a membrane is proposed. In addition, a new scenario of peptide-induced pore formation naturally explaining the similarity of this process under different conditions is suggested.

  13. Adsorption of naphthalene onto a high-surface-area carbon from waste ion exchange resin.

    Science.gov (United States)

    Shi, Qianqian; Li, Aimin; Zhu, Zhaolian; Liu, Bing

    2013-01-01

    A high-surface-area carbon (KC-1) was prepared from waste polystyrene-based ion exchange resin by KOH activation and used for naphthalene adsorption. The carbon exhibited a good hydrophobic nature with developed porous structure, favoring the adsorption of organic compounds. The Brunauer-Emmett-Teller surface area and total pore volume of KC-1 were 3442.2 and 1.68 cm3/g, respectively, which can be compared with those of KOH-activated carbons prepared from other precursors. Batch experiments were carried out to investigate the adsorption of naphthalene onto KC-1. The equilibrium data were analyzed by the Langmuir, Freundlich, and Polanyi-Manes isotherms and agreed with the Polanyi-Manes Model. The adsorption of naphthalene depended greatly on the porosity of the carbon, and the dispersive interactions between naphthalene and carbon could be relatively weak. The pH variation in aqueous solution had little effect on the adsorption process. The equilibrium time for 0.04 g/L of carbon dose was around 5 hr. Different models were used to evaluate the kinetic data and the pseudo second-order model was suitable to describe the kinetic process of naphthalene adsorption onto KC-1. Regeneration of spent carbon could be carried out effectively by alcohol treatment. The results indicated that KC-1 was a promising adsorbent for the removal of polycyclic aromatic hydrocarbons from aqueous solutions.

  14. Kinetic and equilibrium study of adsorption of di-azo dyes on commercial activated carbon

    International Nuclear Information System (INIS)

    Hyali, E.A.S.A.; Abady, T.G.A.

    2013-01-01

    This research work is concerned with studying the adsorption of a number of di-azo dyes on commercial activated carbon (CAC). The synthesized dyes vary in their structures by the central parts. which are either ortho, meta or para phenvlene diamine. This variation affects the linearity of molecules, their spatial arrangement and electron movement throughout the molecule by resonance. Factors a fleeting adsorption process, such as the efiect of contact time, initial concentration, p1-I of the adsorption medium, adsorbent dose, effect of solvent and temperature were studied. The results indicated that, the adsorption process is fast in the first 10 mm, then gradually decreased with time and approaches maximum within 70-80 min for all the studied dyes. The increase of initial concentration and temperature decreased the adsorption efficiency. The results also shows that, the adsorption is found to be more efficient at low Ph value. The increase of the adsorbent dose increases the adsorption efficiency and decreases its capacity. The variation of solvent (ethanol-water ratio) indicates that the decrease of dielectric constant lowers the adsorption efficiency. The study included application of three adsorption isotherms, Freundlich, Langmuir and Tempkin on the experimental data of the studied systems. The results indicated that, Freundlich isotherm fits better the adsorption data. Kinetic analysis of the adsorption data was also conducted by employing 4 kinetic models; pseudo first order and pseudo second order, Elovich and intra particle diffusion equations. The results obtained conclude that, the studied systems follow the Pseudo second order model. (author)

  15. Adsorption of ofloxacin and norfloxacin on carbon nanotubes: hydrophobicity- and structure-controlled process.

    Science.gov (United States)

    Peng, Hongbo; Pan, Bo; Wu, Min; Liu, Ying; Zhang, Di; Xing, Baoshan

    2012-09-30

    Adsorption of antibiotics on solid particles is a key process controlling their fate in the subsurface. This study compared the adsorption of ofloxacin and norfloxacin (NOR) on carbon nanotubes (CNTs) to evaluate the role of structural and hydrophobic properties in regulating their adsorption. A significant relationship was observed between single-point adsorption coefficients (K(d)) and specific surface area (highly hydrophobic), but not between K(d)s and oxygen content. This result suggested that site-specific adsorption was not important but hydrophobic effect may have an important contribution to OFL and NOR adsorption on CNTs. However, normalizing the adsorption coefficients by OFL and NOR solubilities enlarged their adsorption difference indicating that hydrophobicity was not the only factor controlling the difference between OFL and NOR adsorption on CNTs. Their chemical structures show that both chemicals could interact with CNTs through an electron-donor-acceptor mechanism. This mechanism was correlated with the different adsorption of OFL and NOR on functionalized CNTs (namely hydroxylized, carboxylized, and graphitized CNTs). This study revealed that OFL and NOR adsorption was controlled by their both structural- and hydrophobic-properties. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Water desalination using carbon-nanotube-enhanced membrane distillation.

    Science.gov (United States)

    Gethard, Ken; Sae-Khow, Ornthida; Mitra, Somenath

    2011-02-01

    Carbon nanotube (CNT) enhanced membrane distillation is presented for water desalination. It is demonstrated that the immobilization of the CNTs in the pores of a hydrophobic membrane favorably alters the water-membrane interactions to promote vapor permeability while preventing liquid penetration into the membrane pores. For a salt concentration of 34 000 mg L(-1) and at 80 °C, the nanotube incorporation led to 1.85 and 15 times increase in flux and salt reduction, respectively.

  17. Adsorption of Emerging Ionizable Contaminants on Carbon Nanotubes: Advancements and Challenges

    Directory of Open Access Journals (Sweden)

    Xingmao Ma

    2016-05-01

    Full Text Available The superior adsorption capacity of carbon nanotubes has been well recognized and there is a wealth of information in the literature concerning the adsorption of unionized organic pollutants on carbon nanotubes. Recently, the adsorption of emerging environmental pollutants, most of which are ionizable, has attracted increasing attention due to the heightened concerns about the accumulation of these emerging contaminants in the environment. These recent studies suggest that the adsorption of emerging ionizable contaminants on carbon nanotubes exhibit different characteristics than unionized ones. For example, a new charge-assisted intermolecular force has been proposed for ionizable compounds because some adsorption phenomenon cannot be easily explained by the conventional force theory. The adsorption of ionizable compounds also displayed much stronger dependence on solution pH and ionic strength than unionized compounds. This article aims to present a brief review on the current understanding of the adsorption of emerging ionizable contaminants to carbon nanotubes and discuss further research needs required to advance the mechanistic understanding of the interactions between ionizable contaminants and carbon nanotubes.

  18. Water Adsorption with Hysteresis Effect onto Microporous Activated Carbon Fabrics - PREPRINT

    National Research Council Canada - National Science Library

    Sullivan, Patrick D; Stone, Brenton R; Hashiso, Zahar; Rood, Mark J

    2007-01-01

    Understanding the adsorption of water vapor onto activated carbons is important for designing processes to remove dilute contaminants from humid gas streams, such as providing protection against chemical warfare agents (CWAs...

  19. Adsorption, Aggregation, and Deposition Behaviors of Carbon Dots on Minerals.

    Science.gov (United States)

    Liu, Xia; Li, Jiaxing; Huang, Yongshun; Wang, Xiangxue; Zhang, Xiaodong; Wang, Xiangke

    2017-06-06

    The increased production of carbon dots (CDs) and the release and accumulation of CDs in both surface and groundwater has resulted in the increasing interest in their research. To assess the environmental behavior of CDs, the interaction between CDs and goethite was studied under different environmental conditions. Electrokinetic characterization of CDs suggested that the ζ-potential and size distribution of CDs were affected by pH and electrolyte species, indicating that these factors influenced the stability of CDs in aqueous solutions. Traditional Derjaguin-Landau-Verwey-Overbeek theory did not fit well the aggregation process of CDs. Results of the effects of pH and ionic strength suggested that electronic attraction dominated the aggregation of CDs. Compared with other minerals, hydrogen-bonding interactions and Lewis acid-base interactions contributed to the aggregation of CDs, in addition to van der Waals and electrical double-layer forces. Adsorption isotherms and microscopic Fourier transformed infrared spectroscopy indicated that chemical bonds were formed between CDs and goethite. These findings are useful to understand the interaction of CDs with minerals, as well as the potential fate and toxicity of CDs in the natural environment, especially in soils and sediments.

  20. A Review of Carbon Dioxide Selective Membranes: A Topical Report

    Energy Technology Data Exchange (ETDEWEB)

    Dushyant Shekhawat; David R. Luebke; Henry W. Pennline

    2003-12-01

    Carbon dioxide selective membranes provide a viable energy-saving alternative for CO2 separation, since membranes do not require any phase transformation. This review examines various CO2 selective membranes for the separation of CO2 and N2, CO2 and CH4, and CO2 and H2 from flue or fuel gas. This review attempts to summarize recent significant advances reported in the literature about various CO2 selective membranes, their stability, the effect of different parameters on the performance of the membrane, the structure and permeation properties relationships, and the transport mechanism applied in different CO2 selective membranes.

  1. Adsorption of Heavy Metals From Industrial Wastes Using Membranes Prepared by Radiation Grafting

    International Nuclear Information System (INIS)

    Hegazy, E. A.; Kamal, H.; Maziad, N.; Dessouki, A.M.; Aly, H.F.

    1999-01-01

    Preparation of synthetic membranes using simultaneous radiation grafting of acrylic acid (AAc) and styrene (Sty) individually and in a binary monomers mixture onto polypropylene (PP) has been carried out. The effect of preparation conditions such as irradiation dose, monomer and inhibitor concentration, comonomer composition on the grafting yield was investigated. The thermal stability and mechanical properties were also investigated as a function of degree of grafting. Accordingly the possibility of its practical use in industrial waste treatment is determined. The prepared cation-exchange membranes possess good mechanical properties, high thermal stability and good characteristics for separation processes. These membranes have also good affinity toward the adsorption or chelation with Fe 3+ , Pb 2+ , and Cd 2+ ions either in a mixture or exists alone in the solution

  2. Improving the performance of an aerobic membrane bioreactor (MBR) treating pharmaceutical wastewater with powdered activated carbon (PAC) addition.

    Science.gov (United States)

    Kaya, Yasemin; Bacaksiz, A Murat; Golebatmaz, Ugur; Vergili, Ilda; Gönder, Z Beril; Yilmaz, Gulsum

    2016-04-01

    In this study, the effects of organic loading rate (OLR) and the addition of powdered activated carbon (PAC) on the performance and membrane fouling of MBR were conducted to treat real pharmaceutical process wastewater. Over 145 days of operation, the MBR system was operated at OLRs ranging from 1 to 2 kg COD m(-3) day(-1) without sludge wasting. The addition of PAC provided an improvement in the flux, despite an increase in the OLR:PAC ratio. The results demonstrated that the hybrid PAC-MBR system maintained a reduced amount of membrane fouling and steadily increased the removal performance of etodolac. PAC addition reduced the deposition of extracellular polymeric substance and organic matter on the membrane surface and resulted an increase in COD removal even at higher OLRs with low PAC addition. Membrane fouling mechanisms were investigated using combined adsorption fouling models. Modified fouling index values and normalized mass transfer coefficient values indicated that predominant fouling mechanism was cake adsorption.

  3. Utilization of spent dregs for the production of activated carbon for CO2 adsorption

    Directory of Open Access Journals (Sweden)

    Serafin Jarosław

    2017-06-01

    Full Text Available The objective of this work was preparation of activated carbon from spent dregs for carbon dioxide adsorption. A saturated solution of KOH was used as an activating agent. Samples were carbonized in the furnace at the temperature of 550°C. Textural properties of activated carbons were obtained based on the adsorption-desorption isotherms of nitrogen at −196°C and carbon dioxide at 0°C. The specific surface areas of activated carbons were calculated by the Brunauer – Emmett – Teller equation. The volumes of micropores were obtained by density functional theory method. The highest CO2 adsorption was 9.54 mmol/cm3 at 0°C – and 8.50 mmol/cm3 at 25°C.

  4. Adsorption of hexane, cyclohexane, and benzene on microporous carbon obtained by pyrolysis of hypercrosslinked polystyrene

    Science.gov (United States)

    Asnin, L. D.; Davankov, V. A.

    2011-09-01

    The relationships of adsorption of hexane, cyclohexane, and benzene on a D4609 microporous carbon adsorbent obtained by the pyrolysis of hypercrosslinked polystyrene are compared. It is shown that in the range of relative pressures corresponding to the filling of ultramicropores, the adsorption behaviors of cyclohexane and benzene are essentially identical, in contrast to hexane, which is characterized by higher adsorption values and isosteric heat of adsorption. The observed relationships are explained by the steric features of the distribution of molecules of various structures in ultramicropores.

  5. Modeling and Optimization for Production of Rice Husk Activated Carbon and Adsorption of Phenol

    OpenAIRE

    Mohammad, Y. S.; Shaibu-Imodagbe, E. M.; Igboro, S. B.; Giwa, A.; Okuofu, C. A.

    2014-01-01

    Modeling of adsorption process establishes mathematical relationship between the interacting process variables and process optimization is important in determining the values of factors for which the response is at maximum. In this paper, response surface methodology was employed for the modeling and optimization of adsorption of phenol onto rice husk activated carbon. Among the action variables considered are activated carbon pretreatment temperature, adsorbent dosage, and initial concentrat...

  6. Adsorption kinetics of propane on energetically heterogeneous activated carbon

    KAUST Repository

    Ismail, Azhar Bin

    2014-11-01

    The modeling of the adsorption isotherms and kinetics of the adsorbent+adsorbate pair is essential in simulating the performance of a pressurized adsorption chiller. In this work, the adsorption kinetics is analyzed from data measured using a magnetic suspension balance. The Statistical Rate Theory describes the Dubinin-Astakhov (DA) equation and extended to obtain an expression for transient analysis. Hence both the experimental excess equilibria data and the adsorption kinetics data may then be fitted to obtain the necessary parameters to fit the curves. The results fit the data very well within 6% of the error of regression. © 2014 Elsevier Ltd.

  7. Preparation of a novel Zr(4+)-immobilized metal affinity membrane for selective adsorption of phosphoprotein.

    Science.gov (United States)

    He, Maofang; Wang, Chaozhan; Wei, Yinmao

    2016-09-01

    In this study, a novel phosphate-Zr(4+) immobilized metal affinity membrane (IMAM) was prepared based on the surface initiated-atom transfer radical polymerization technique for the selective adsorption of phosphoprotein. The adsorption capacity and selectivity of the phosphate-Zr(4+) IMAM were evaluated by using the mixture of standard phosphoproteins (β-casein, ovalbumin) and nonphosphoproteins (bovine serum albumin and lysozyme) as model samples. The adsorption isotherms and competitive adsorption results demonstrated that the phosphate-Zr(4+) IMAM had higher binding capacity and selectivity for phosphoproteins over nonphosphoproteins. Moreover, the phosphate-Zr(4+) IMAM exhibited good re-usability and re-productivity. Finally, the phosphate-Zr(4+) IMAM was applied to separate phosphoprotein from real samples with high purity. Therefore, the as-prepared phosphate-Zr(4+) IMAM could be a promising affinity material for the efficient enrichment of phosphoprotein from complex bio-samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Solvent-extraction and Langmuir-adsorption-based transport in chemically functionalized nanopore membranes.

    Science.gov (United States)

    Odom, Damian J; Baker, Lane A; Martin, Charles R

    2005-11-10

    We have investigated the transport properties of nanopore alumina membranes that were rendered hydrophobic by functionalization with octadecyltrimethoxysilane (ODS). The pores in these ODS-modified membranes are so hydrophobic that they are not wetted by water. Nevertheless, nonionic molecules can be transported from an aqueous feed solution on one side of the membrane, through the dry nanopores, and into an aqueous receiver solution on the other side. The transport mechanism involves Langmuir-type adsorption of the permeating molecule onto the ODS layers lining the pore walls, followed by solid-state diffusion along these ODS layers; we have measured the diffusion coefficients associated with this transport process. We have also investigated the transport properties of membranes prepared by filling the ODS-modified pores with the water-immiscible (hydrophobic) liquid mineral oil. In this case the transport mechanism involves solvent extraction of the permeating molecule into the mineral oil subphase confined with the pores, followed by solution-based diffusion through this liquid subphase. Because of this different transport mechanism, the supported-liquid membranes show substantially better transport selectivity than the ODS-modified membranes that contain no liquid subphase.

  9. Adsorption behavior of multi-walled carbon nanotubes for the removal of olaquindox from aqueous solutions

    International Nuclear Information System (INIS)

    Zhang, Lei; Xu, Tianci; Liu, Xueyan; Zhang, Yunyu; Jin, Hongjing

    2011-01-01

    Highlights: ► Removal of olaquindox—a hazardous pollutant using MWCNT was investigated. ► A comparative analysis showed MWCNT was highly efficient for the removal of olaquindox. ► Adsorption equilibrium was reached in 2.0 min following pseudo-second-order model. ► Physisorption and inner diffusion are the characteristics of the adsorption system. ► Langmuir adsorption isotherms are adequate for modeling the adsorption process. - Abstract: Multi-walled carbon nanotubes (MWCNT) were employed for the sorption of olaquindox (OLA) from aqueous solution. A detailed study of the adsorption process was performed by varying pH, ionic strength, sorbent amount, sorption time and temperature. The adsorption mechanism is probably the non-electrostatic π–π dispersion interaction and hydrophobic interaction between OLA and MWCNT. The adsorption efficiency could reach 99.7%, suggesting that MWCNT is excellent adsorbents for effective OLA removal from water. OLA adsorption kinetics were found to be very fast and equilibrium was reached within 2.0 min following the pseudo-second-order model with observed rate constants (k) of 0.169–1.048 g mg −1 min −1 (at varied temperatures). The overall rate process appeared to be influenced by both external mass transfer and intraparticle diffusion, but mainly governed by intraparticle diffusion. A rapid initial adsorption behavior occurred within a short period of time in this adsorption system. The sorption data could be well interpreted by the Langmuir model with the maximum adsorption capacity of 133.156 mg g −1 (293 K) of OLA on MWCNT. The mean energy of adsorption was calculated to be 0.124 kJ mol −1 (293 K) from the Dubinin–Radushkevich adsorption isotherm. Moreover, the thermodynamic parameters showed the spontaneous, exothermic and physical nature of the adsorption process.

  10. Efficient adsorption of Hg (II) ions in water by activated carbon modified with melamine

    Science.gov (United States)

    Qin, Hangdao; Meng, Jingling; Chen, Jing

    2018-04-01

    Removal of Hg (II) ions from industrial wastewater is important for the water treatment, and adsorption is an efficient treatment process. Activated carbon (AC) was modified with melamine, which introduced nitrogen-containing functional groups onto AC surface. Original AC and melamine modified activated carbon (ACM) were characterized by elemental analysis, N2 adsorption-desorption, determination of the pH of the point of zero charge (pHpzc) and X-ray photoelectron spectroscopy (XPS) and their performance in the adsorption of Hg(II) ions was investigated. Langmuir model fitted the experimental data of equilibrium isotherms well. ACM showed the higher Hg (II) ions adsorption capacity, increasing more than more than 1.8 times compared to the original one. Moreover, ACM showed a wider pH range for the maximum adsorption than the parent AC.

  11. Carbon Dioxide Adsorption on a 5A Zeolite Designed for CO2 Removal in Spacecraft Cabins

    Science.gov (United States)

    Mulloth, Lila M.; Finn, John E.

    1998-01-01

    Carbon dioxide adsorption data were obtained for a 5A zeolite manufactured by AlliedSignal Inc. (Des Plaines, Illinois). The material is planned for use in the Carbon Dioxide Removal Assembly (CDRA) for U.S. elements of the International Space Station. The family of adsorption isotherms covers a temperature range of O to 250 C, and a pressure range of 0.001 to 800 torr. Coefficients of the Toth equation are fit to the data. Isosteric heats of adsorption are derived from the equilibrium loading data.

  12. Simultaneous concentration and detoxification of lignocellulosic hydrolyzates by vacuum membrane distillation coupled with adsorption.

    Science.gov (United States)

    Zhang, Yaqin; Li, Ming; Wang, Yafei; Ji, Xiaosheng; Zhang, Lin; Hou, Lian

    2015-12-01

    Low sugar concentration and the presence of various inhibitors are the major challenges associated with lignocellulosic hydrolyzates as a fermentation broth. Vacuum membrane distillation (VMD) process can be used to concentrate sugars and remove inhibitors (furans) efficiently, but it's not desirable for the removal of less volatile inhibitors such as acetic acid. In this study, a VMD-adsorption process was proposed to improve the removal of acetic acid, achieving simultaneous concentration and detoxification of lignocellulosic hydrolyzates by one step process. Results showed that sugars were concentrated with high rejections (>98%) and little sugar loss (<2%), with the significant reduction in nearly total furans (99.7%) and acetic acid (83.5%) under optimal operation conditions. Fermentation results showed the ethanol production of hydrolyzates concentrated and detoxified using the VMD-adsorption method were approximately 10-fold greater than from untreated hydrolyzates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Characterization of pore structure of several activated carbons with different radon adsorption capabilities

    International Nuclear Information System (INIS)

    Wang Qingbo; Qu Jingyuan; Cao Jianzhu; Zhu Wenkai; Zhou Baichang; Cheng Jinchang; Zhang Huimin

    2011-01-01

    The radon dynamic adsorption coefficients (DAC) of four types of activated carbons measured in radon room are different from each other. The pore structures (specific surface area, pore size distribution, pore volume, etc.) influence the adsorption ability significantly. Physical adsorption of inert nitrogen was used for evaluation pore structures of those four activated carbon samples. The results show that activated carbon with specific surface area about 800 m 2 /g has the strong adsorption ability to radon and when the specific surface areas are close, the adsorption ability to radon increases with the micropore specific surface's percentage. Pore size distribution (PSD) was calculated by H-K, BJH and density function theory (DFT). The Micropore size distribution calculation by H-K method shows that pore with size between 0.7-2 nm plays the most important role for adsorption of radon. Mesopore size distribution calculated by BJH method and DFT method shows that mesopore distribution with discrete peaks is more useful to help radon adsorption on activated carbons. (authors)

  14. Adsorption of cationic dye methylene blue onto activated carbon obtained from horse chestnut kernel

    Directory of Open Access Journals (Sweden)

    Momčilović Milan Z.

    2011-01-01

    Full Text Available Horse chestnut kernel was used as the precursor for the preparation of powdered activated carbon using phosphoric acid as the activating agent. Batch adsorption experiments for the adsorption of cationic dye methylene blue from aqueous solutions were carried out using the obtained carbon as adsorbent. Equilibrium and kinetic experiments were conducted. The equilibrium data were fitted with the Langmuir, Freundlich and Temkin theoretical isotherm models. The best results was obtained in the case of Langmuir model, which indicates that monolayer adsorption occurs on finite number of the active adsorption sites on the carbon surface. The kinetic data were fitted with pseudo-first, pseudo-second, Elovich and interparticle diffusion model. Pseudo-second order model and Elovich model showed the best results of the kinetic data. The increasing of the solution pH led to a higher uptake of methylene blue due to the fact that competitive adsorption of methylene blue cation and proton exists in acidic solutions. The adsorption capacity for methylene blue in equilibrium study was significant (168.93 mg g-1. Comparison of the adsorption capacities of methylene blue onto activated carbons derived from various alternative precursors proves chestnut kernel to be efficient and low-cost material which could be substantially deployed in the future.

  15. Cobalt nanoparticles-embedded magnetic ordered mesoporous carbon for highly effective adsorption of rhodamine B

    International Nuclear Information System (INIS)

    Tang, Lin; Cai, Ye; Yang, Guide; Liu, Yuanyuan; Zeng, Guangming; Zhou, Yaoyu; Li, Sisi; Wang, Jiajia; Zhang, Sheng; Fang, Yan; He, Yibin

    2014-01-01

    Highlights: • Cobalt nanoparticles-embedded magnetic ordered mesoporous carbon (Co/OMC) was applied as a novel adsorption material to remove rhodamine B. • Co/OMC was synthesized by directly introducing cobalt into OMC through a simple infusing method. • High removal capacity of rhodamine B: maximum adsorption capacity reaches 468 mg/g at 200 mg/L initial rhodamine B concentration. • Very quick adsorption property: 96% of rhodamine B can be removed within 25 min. - Abstract: Cobalt nanoparticles-embedded magnetic ordered mesoporous carbon (Co/OMC), prepared through a simple method involving infusing and calcination, was used as a highly effective adsorbent for rhodamine B (Rh B) removal. Several techniques, including SEM, HRTEM, nitrogen adsorption–desorption isotherms, XRD, Raman spectra, EDX, zeta potential and VSM measurement, were applied to characterize the adsorbent. Batch tests were conducted to investigate the adsorption performance. The adsorption capacity of the resultant adsorbent was relatively high compared with raw ordered mesoporous carbon (OMC) and reached an equilibrium value of 468 mg/g at 200 mg/L initial Rh B concentration. Removal efficiency even reached 96% within 25 min at 100 mg/L initial Rh B concentration. Besides, the adsorption amount increased with the increase of solution pH, adsorbent dose and initial Rh B concentration. Kinetics study showed that the adsorption agreed well with pseudo-second-order model (R 2 = 0.999) and had a significant correlation with intra-particle diffusion model in the both two adsorption periods. Furthermore, thermodynamics research indicated that the adsorption process was endothermic and spontaneous in nature. The adsorption isotherms fitted well with Langmuir model, demonstrating the formation of mono-molecular layer on the surface of Co/OMC during adsorption process. The results confirmed that Co/OMC has the potential superiority in removal of Rh B from aqueous solution

  16. Cobalt nanoparticles-embedded magnetic ordered mesoporous carbon for highly effective adsorption of rhodamine B

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Lin, E-mail: tanglin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Cai, Ye; Yang, Guide; Liu, Yuanyuan [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Zhou, Yaoyu; Li, Sisi; Wang, Jiajia; Zhang, Sheng; Fang, Yan; He, Yibin [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China)

    2014-09-30

    Highlights: • Cobalt nanoparticles-embedded magnetic ordered mesoporous carbon (Co/OMC) was applied as a novel adsorption material to remove rhodamine B. • Co/OMC was synthesized by directly introducing cobalt into OMC through a simple infusing method. • High removal capacity of rhodamine B: maximum adsorption capacity reaches 468 mg/g at 200 mg/L initial rhodamine B concentration. • Very quick adsorption property: 96% of rhodamine B can be removed within 25 min. - Abstract: Cobalt nanoparticles-embedded magnetic ordered mesoporous carbon (Co/OMC), prepared through a simple method involving infusing and calcination, was used as a highly effective adsorbent for rhodamine B (Rh B) removal. Several techniques, including SEM, HRTEM, nitrogen adsorption–desorption isotherms, XRD, Raman spectra, EDX, zeta potential and VSM measurement, were applied to characterize the adsorbent. Batch tests were conducted to investigate the adsorption performance. The adsorption capacity of the resultant adsorbent was relatively high compared with raw ordered mesoporous carbon (OMC) and reached an equilibrium value of 468 mg/g at 200 mg/L initial Rh B concentration. Removal efficiency even reached 96% within 25 min at 100 mg/L initial Rh B concentration. Besides, the adsorption amount increased with the increase of solution pH, adsorbent dose and initial Rh B concentration. Kinetics study showed that the adsorption agreed well with pseudo-second-order model (R{sup 2} = 0.999) and had a significant correlation with intra-particle diffusion model in the both two adsorption periods. Furthermore, thermodynamics research indicated that the adsorption process was endothermic and spontaneous in nature. The adsorption isotherms fitted well with Langmuir model, demonstrating the formation of mono-molecular layer on the surface of Co/OMC during adsorption process. The results confirmed that Co/OMC has the potential superiority in removal of Rh B from aqueous solution.

  17. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    International Nuclear Information System (INIS)

    Yoosefian, Mehdi

    2017-01-01

    Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N 2 O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N 2 O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N 2 O onto CNT, the horizontal adsorption with E ads = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N 2 O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N 2 O were investigated. Adsorption of N 2 O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N 2 O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N 2 O sensors.

  18. The fabrication of porous N-doped carbon from widely available urea formaldehyde resin for carbon dioxide adsorption.

    Science.gov (United States)

    Liu, Zhen; Du, Zhenyu; Song, Hao; Wang, Chuangye; Subhan, Fazle; Xing, Wei; Yan, Zifeng

    2014-02-15

    N-doped carbon material constitutes abundant of micropores and basic nitrogen species that have potential implementation for CO2 capture. In this paper, porous carbon material with high nitrogen content was simply fabricated by carbonizing low cost and widely available urea formaldehyde resin, and then followed by KOH activation. CO2 capture experiment showed high adsorption capacity of 3.21 mmol g(-1) at 25 °C under 1 atm for UFCA-2-600. XRD, SEM, XPS and FT-IR analysis confirmed that a graphitic-like structure was retained even after high temperature carbonization and strong base activation. Textural property analysis revealed that narrow micropores, especially below 0.8 nm, were effective for CO2 adsorption by physical adsorption mechanism. Chemical evolved investigation revealed that graphitic-like embedded basic nitrogen groups are generated from bridged and terminal amines of urea formaldehyde resin from thermal carbonization and KOH activation treatment, which is responsible for the enrichment of CO2 capacity by chemical adsorption mechanism. The relationship between CO2 adsorption capacity and pore size or basic N species was also studied, which turned out that both of them played crucial role by physical and chemical adsorption mechanism, respectively. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. NOVEL CERAMIC MEMBRANE FOR HIGH TEMPERATURE CARBON DIOXIDE SEPARATION; SEMIANNUAL

    International Nuclear Information System (INIS)

    Jerry Y.S. Lin; Jun-ichi Ida

    2001-01-01

    This project is aimed at demonstrating technical feasibility for a lithium zirconate based dense ceramic membrane for separation of carbon dioxide from flue gas at high temperature. The research work conducted in this reporting period was focused on several fundamental issues of lithium zirconate important to the development of the dense inorganic membrane. These fundamental issues include material synthesis of lithium zirconate, phases and microstructure of lithium zirconate and structure change of lithium zirconate during sorption/desorption process. The results show difficulty to prepare the dense ceramic membrane from pure lithium zirconate, but indicate a possibility to prepare the dense inorganic membrane for carbon dioxide separation from a composite lithium zirconate

  20. Recent Advances on Carbon Molecular Sieve Membranes (CMSMs and Reactors

    Directory of Open Access Journals (Sweden)

    Margot A. Llosa Tanco

    2016-08-01

    Full Text Available Carbon molecular sieve membranes (CMSMs are an important alternative for gas separation because of their ease of manufacture, high selectivity due to molecular sieve separation, and high permeance. The integration of separation by membranes and reaction in only one unit lead to a high degree of process integration/intensification, with associated benefits of increased energy, production efficiencies and reduced reactor or catalyst volume. This review focuses on recent advances in carbon molecular sieve membranes and their applications in membrane reactors.

  1. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Rocklan; Dutech, Guy

    2014-09-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  2. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    International Nuclear Information System (INIS)

    McDowell, Rocklan; Dutech, Guy

    2014-01-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  3. Adsorption of crystal violet with diatomite earth&carbon by a modification of hydrothermal carbonization process.

    Science.gov (United States)

    Zhang, Yanzhuo; Li, Jun; Chen, Guanghui; Bian, Wei; Lu, Yun; Li, Wenjing; Zheng, Zhaoming; Cheng, Xiaojie

    2016-01-01

    The high colority and difficulty of decolorization are the most important tasks on printing and dyeing wastewater. This study investigates the ability of diatomite earth&carbon (DE&C) as an adsorbent to removal crystal violet (CV) from aqueous solutions. Fourier transform infrared spectroscopy results indicate the importance of functional groups during the adsorption of CV. The obtained N2 adsorption-desorption isotherm values accord with well IUPAC type II. Our calculations determined a surface area of 73.15 m(2) g(-1) for DE&C and an average pore diameter of 10.56 nm. Equilibrium data of the adsorption process fitted very well to the Langmuir model (R(2) > 0.99). The results of kinetics study showed that the pseudo-second-order model fitted to the experimental data well. The thermodynamic parameters were also evaluated. ΔH° 0 and ΔG° dye. Furthermore the positive value of ΔS° reflected good affinity of the CV dye.

  4. Kinetics of diuron and amitrole adsorption from aqueous solution on activated carbons.

    Science.gov (United States)

    Fontecha-Cámara, M A; López-Ramón, M V; Pastrana-Martínez, L M; Moreno-Castilla, C

    2008-08-15

    A study was conducted on the adsorption kinetics of diuron and amitrole from aqueous solutions on activated carbons of different particle sizes and on an activated carbon fiber. Different kinetic models were applied to the experimental results obtained. A pseudo-second-order rate equation fitted the adsorption kinetics data better than a pseudo-first-order rate equation. Amitrole showed faster adsorption kinetics compared with diuron because of the smaller size of the former herbicide, despite its lower driving force for adsorption. Both reaction rate constants increased when the particle size decreased. The activated carbon fiber and the activated carbon of smallest particle size (0.03 mm) showed similar adsorption kinetics. The intraparticle diffusion rate constant increased with higher initial concentration of herbicides in solution and with lower particle size of the adsorbent. This is because the rise in initial concentration increased the amount adsorbed at equilibrium, and the reduction in particle size increased the number of collisions between adsorbate and adsorbent particles. Demineralization of the activated carbon with particle size of 0.5mm had practically no effect on the adsorption kinetics.

  5. Investigation of the adsorption of water vapor and carbon dioxide by KA zeolite

    International Nuclear Information System (INIS)

    Khanitonov, V.P.; Shtein, A.S.

    1984-01-01

    According to the present data, KA zeolite, which can adsorb only water vapor, helium, and hydrogen, has the greatest selectivity in drying. The feasibility of using this zeolite in devices for selective drying of gases used in gas-analysis systems was studied. The results of the experiments were approximated by the thermal equation of the theory of bulk filling of micropores. The limiting value of the adsorption depends on the temperature, and it can be calculated according to the density of the adsorbed phase and the adsorption volume. The critical diameters of the water and carbon dioxide molecules are close to the dimensions of the KA-zeolite pores, something that determines the activated nature of the adsorption of these substances. Experiments on coadsorption of water vapor and carbon dioxide by a fixed bed of KA-zeolite under dynamic conditions showed that the adsorption of these substances has a frontal nature. The time of the protective action of the layer of zeolite during adsorption af water vapor exceeded by more than an order the time of the protective action during adsorption of carbon dioxide. The results showed that this adsorbent can be used for selective drying of gas mixtures containing carbon dioxide in batch-operation devices. Beforehand, the adsorbent should be regenerated with respect to moisture, and then it should be saturated with carbon dioxide by blowing the adsorbent with a gas mixture of the working composition until the equilibrium state is reached

  6. Preparation of Starch-Hard Carbon Spherules from Ginkgo Seeds and Their Phenol-Adsorption Characteristics.

    Science.gov (United States)

    Chen, Hongxia; Wang, Chengzhang; Ye, Jianzhong; Zhou, Hao; Tao, Ran; Li, Wenjun

    2018-01-02

    Carbon spherules from ginkgo seed starch were prepared through stabilization and carbonization processes. The ginkgo seed starch was first stabilized at 195 °C for 18 h, then carbonized at 500 °C for 2 h under an N₂ atmosphere. The characterization results confirmed that carbon spherules were in the size range of 10-20 μm. Experimental data were also evaluated to find out the kinetic characteristics of phenols on the carbon spherules during the adsorption process. Adsorption processes for phenol, p -nitrophenol and p -chlorophenol were found to follow the pseudo-first order kinetic model with R ² values of 0.995, 0.997 and 0.998, while the rate constants k ₁ = 0.014, 0.009 and 0.011 min -1 showed that the adsorption is mainly controlled by adsorbate diffusion. The equilibrium data were analyzed with the Langmuir, Freundlich and Temkin-Pyzhev models and the best fit was observed with the Freundlich isotherm, suggesting the physical adsorption of phenols. From the thermodynamic functions, ∆G, ∆H, and ∆S were calculated, which showed that adsorption is more favorable at low temperature and is an exothermic process, and the adsorption of p -nitrophenol and p -chlorophenol were more advantageous than that of phenol.

  7. Regulation of anionic lipids in binary membrane upon the adsorption of polyelectrolyte: A Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Xiaozheng Duan

    2013-06-01

    Full Text Available We employ Monte Carlo simulations to investigate the interaction between an adsorbing linear flexible cationic polyelectrolyte and a binary fluid membrane. The membrane contains neutral phosphatidyl–choline, PC and multivalent anionic (phosphatidylinositol, PIP2 lipids. We systematically study the influences of the solution ionic strength, the chain length and the bead charge density of the polyelectrolyte on the lateral rearrangement and the restricted mobility of the multivalent anionic lipids in the membrane. Our findings show that, the cooperativity effect and the electrostatic interaction of the polyelectrolyte beads can significantly affect the segregation extent and the concentration gradients of the PIP2 molecules, and further cooperate to induce the complicated hierarchical mobility behaviors of PIP2 molecules. In addition, when the polyelectrolyte brings a large amount of charges, it can form a robust electrostatic well to trap all PIP2 and results in local overcharge of the membrane. This work presents a mechanism to explain the membrane heterogeneity formation induced by the adsorption of charged macromolecule.

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

    Directory of Open Access Journals (Sweden)

    Muhammad Said

    2016-08-01

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

  9. Effect of effluent organic matter on the adsorption of perfluorinated compounds onto activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jing [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); College of Environmental Science and Engineering, Yangzhou University, 196 West Huayang Road, Yangzhou 225127 (China); Lv, Lu, E-mail: esellu@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Lan, Pei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); College of Environmental Science and Engineering, Yangzhou University, 196 West Huayang Road, Yangzhou 225127 (China); Zhang, Shujuan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Pan, Bingcai, E-mail: bcpan@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Zhang, Weiming [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer The presence of EfOM significantly reduced the adsorption capacities and rates of PFCs. Black-Right-Pointing-Pointer Low-molecular-weight EfOM compounds (<1 kDa) compete for adsorption sites of PFSs directly. Black-Right-Pointing-Pointer Large-molecular-weight EfOM compounds (>30 kDa) affect the adsorption through pore blockage or restriction effect. Black-Right-Pointing-Pointer Changes in surface properties of PAC caused by preloaded EfOM could affect PFCs adsorption. - Abstract: Effect of effluent organic matter (EfOM) on the adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) onto powdered activated carbon (PAC) was quantitatively investigated at environmentally relevant concentration levels. The adsorption of both perfluorinated compounds (PFCs) onto PAC followed pseudo-second order kinetics and fitted the Freundlich model well under the given conditions. Intraparticle diffusion was found to be the rate-controlling step in the PFC adsorption process onto PAC in the absence and presence of EfOM. The presence of EfOM, either in PFC-EfOM simultaneous adsorption onto fresh PAC or in PFC adsorption onto EfOM-preloaded PAC, significantly reduced the adsorption capacities and sorption rates of PFCs. The pH of zero point of charge was found to be 7.5 for fresh PAC and 4.2 for EfOM-preloaded PAC, suggesting that the adsorbed EfOM imparted a negative charge on PAC surface. The effect of molecular weight distribution of EfOM on the adsorption of PFCs was investigated with two EfOM fractions obtained by ultrafiltration. The low-molecular-weight compounds (<1 kDa) were found to be the major contributors to the significant reduction in PFC adsorption capacity, while large-molecular-weight compounds (>30 kDa) had much less effect on PFC adsorption capacity.

  10. Mesoporous carbon adsorbents from melamine-formaldehyde resin using nanocasting technique for CO2 adsorption.

    Science.gov (United States)

    Goel, Chitrakshi; Bhunia, Haripada; Bajpai, Pramod K

    2015-06-01

    Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepared by varying the carbonization temperature from 400 to 700°C. Adsorbents were characterized thoroughly by nitrogen sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), elemental (CHN) analysis, Fourier transform infrared (FTIR) spectroscopy and Boehm titration. Carbonization temperature controlled the properties of the synthesized adsorbents ranging from surface area to their nitrogen content, which play major role in their application as adsorbents for CO2 capture. The nanostructure of these materials was confirmed by XRD and TEM. Their nitrogen content decreased with an increase in carbonization temperature while other properties like surface area, pore volume, thermal stability and surface basicity increased with the carbonization temperature. These materials were evaluated for CO2 adsorption by fixed-bed column adsorption experiments. Adsorbent synthesized at 700°C was found to have the highest surface area and surface basicity along with maximum CO2 adsorption capacity among the synthesized adsorbents. Breakthrough time and CO2 equilibrium adsorption capacity were investigated from the breakthrough curves and were found to decrease with increase in adsorption temperature. Adsorption process for carbon adsorbent-CO2 system was found to be reversible with stable adsorption capacity over four consecutive adsorption-desorption cycles. From three isotherm models used to analyze the equilibrium data, Temkin isotherm model presented a nearly perfect fit implying the heterogeneous adsorbent surface. Copyright © 2015. Published by Elsevier B.V.

  11. Adsorption kinetics of NO on ordered mesoporous carbon (OMC) and cerium-containing OMC (Ce-OMC)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jinghuan; Cao, Feifei; Chen, Songze; Ni, Mingjiang; Gao, Xiang, E-mail: xgao1@zju.edu.cn; Cen, Kefa

    2014-10-30

    Graphical abstract: - Highlights: • Ordered mesoporous carbon (OMC) and Ce-OMC were used for NO adsorption. • The NO adsorption capacity of OMC was two times larger than that of activated carbon. • With the addition of cerium both adsorption capacity and adsorption rate increased. • The pseudo-second-order model was the most suitable model for NO adsorption on OMC. • Intraparticle diffusion was the rate controlling step for NO adsorption. - Abstract: Ordered mesoporous carbon (OMC) and cerium-containing OMC (Ce-OMC) were prepared using evaporation-induced self-assembly (EISA) method and used to adsorb NO. N{sub 2} sorption, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm their structures. The results showed that the ordered and uniform structures were successfully synthesized and with the introduction of cerium pore properties were not significantly changed. The NO adsorption capacity of OMC was two times larger than that of activated carbon (AC). With the introduction of cerium both the adsorption capacity and the adsorption rate were improved. The effects of residence time and oxygen concentration on NO adsorption were also investigated. Oxygen played an important role in the NO adsorption (especially in the form of chemisorption) and residence time had small influence on the NO adsorption capacity. The NO adsorption kinetics was analyzed using pseudo-first-order, pseudo-second-order, Elovich equation and intraparticle diffusion models. The results indicated that the NO adsorption process can be divided into rapid adsorption period, slow adsorption period, and equilibrium adsorption period. The pseudo-second-order model was the most suitable model for NO adsorption on OMC and Ce-OMC. The rate controlling step was the intraparticle diffusion together with the adsorption reaction.

  12. Adsorption kinetics of NO on ordered mesoporous carbon (OMC) and cerium-containing OMC (Ce-OMC)

    International Nuclear Information System (INIS)

    Chen, Jinghuan; Cao, Feifei; Chen, Songze; Ni, Mingjiang; Gao, Xiang; Cen, Kefa

    2014-01-01

    Graphical abstract: - Highlights: • Ordered mesoporous carbon (OMC) and Ce-OMC were used for NO adsorption. • The NO adsorption capacity of OMC was two times larger than that of activated carbon. • With the addition of cerium both adsorption capacity and adsorption rate increased. • The pseudo-second-order model was the most suitable model for NO adsorption on OMC. • Intraparticle diffusion was the rate controlling step for NO adsorption. - Abstract: Ordered mesoporous carbon (OMC) and cerium-containing OMC (Ce-OMC) were prepared using evaporation-induced self-assembly (EISA) method and used to adsorb NO. N 2 sorption, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm their structures. The results showed that the ordered and uniform structures were successfully synthesized and with the introduction of cerium pore properties were not significantly changed. The NO adsorption capacity of OMC was two times larger than that of activated carbon (AC). With the introduction of cerium both the adsorption capacity and the adsorption rate were improved. The effects of residence time and oxygen concentration on NO adsorption were also investigated. Oxygen played an important role in the NO adsorption (especially in the form of chemisorption) and residence time had small influence on the NO adsorption capacity. The NO adsorption kinetics was analyzed using pseudo-first-order, pseudo-second-order, Elovich equation and intraparticle diffusion models. The results indicated that the NO adsorption process can be divided into rapid adsorption period, slow adsorption period, and equilibrium adsorption period. The pseudo-second-order model was the most suitable model for NO adsorption on OMC and Ce-OMC. The rate controlling step was the intraparticle diffusion together with the adsorption reaction

  13. Progress and challenges of carbon nanotube membrane in water treatment

    KAUST Repository

    Lee, Jieun

    2016-05-25

    The potential of the carbon nanotube (CNT) membrane has been highly strengthened in water treatment during the last decade. According to works published up to now, the unique and excellent characteristics of CNT outperformed conventional polymer membranes. Such achievements of CNT membranes are greatly dependent on their fabrication methods. Further, the intrinsic properties of CNT could be a critical factor of applicability to membrane processes. This article provides an explicit and systematic review of the progress of CNT membranes addressing the current epidemic—whether (i) the CNT membranes could tackle current challenges in the pressure- or thermally driven membrane processes and (ii) CNT hybrid nanocomposite as a new generation of materials could complement current CNT-enhanced membrane. © 2016 Taylor & Francis Group, LLC.

  14. Adsorption of Lead ions onto Activated Carbon derived from Sugarcane bagasse

    Science.gov (United States)

    Salihi, I. U.; Kutty, S. R. M.; Isa, M. H.

    2017-05-01

    In this study, activated carbon was developed from sugarcane bagasse and its effectiveness in adsorbing lead (Pb2+) ions from synthetic aqueous solution was examined. Sugarcane bagasse activated carbon (SCBA) was developed in a tube furnace at a temperature of 900 °C, a heating rate of 10 °C/min, residence time of 3 hours, and at a nitrogen flow rate of 100 mL/min. Batch adsorption experiments were carried out to investigate the effects of pH and SCBA dosages on the adsorption process. The batch adsorption test showed that extent of Pb2+ adsorption by SCBA was dependent upon pH and SCBA dosage. The optimum pH for Pb2+ adsorption was found to be at pH 5.0. Maximum Pb2+ removal efficiency obtained from the batch studies was 87.3 % at SCBA dosage of 10 g/L. Equilibrium adsorption data was described by Langmuir model with a coefficient of determination (R2) of 0.9508. Maximum adsorption capacity according to Langmuir model was evaluated to be 23.4 mg/g. The adsorption capacity of the SCBA was compared with that of other plant-based adsorbents. SCBA is an effective adsorbent for the removal of Pb2+ from aqueous solution.

  15. Individual and competitive adsorption of phenol and nickel onto multiwalled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Nour T. Abdel-Ghani

    2015-05-01

    Full Text Available Individual and competitive adsorption studies were carried out to investigate the removal of phenol and nickel ions by adsorption onto multiwalled carbon nanotubes (MWCNTs. The carbon nanotubes were characterized by different techniques such as X-ray diffraction, scanning electron microscopy, thermal analysis and Fourier transformation infrared spectroscopy. The different experimental conditions affecting the adsorption process were investigated. Kinetics and equilibrium models were tested for fitting the adsorption experimental data. The characterization experimental results proved that the studied adsorbent possess different surface functional groups as well as typical morphological features. The batch experiments revealed that 300 min of contact time was enough to achieve equilibrium for the adsorption of both phenol and nickel at an initial adsorbate concentration of 25 mg/l, an adsorbent dosage of 5 g/l, and a solution pH of 7. The adsorption of phenol and nickel by MWCNTs followed the pseudo-second order kinetic model and the intraparticle diffusion model was quite good in describing the adsorption mechanism. The Langmuir equilibrium model fitted well the experimental data indicating the homogeneity of the adsorbent surface sites. The maximum Langmuir adsorption capacities were found to be 32.23 and 6.09 mg/g, for phenol and Ni ions, respectively. The removal efficiency of MWCNTs for nickel ions or phenol in real wastewater samples at the optimum conditions reached up to 60% and 70%, respectively.

  16. Inorganic membranes for carbon capture and power generation

    Science.gov (United States)

    Snider, Matthew T.

    Inorganic membranes are under consideration for cost-effective reductions of carbon emissions from coal-fired power plants, both in the capture of pollutants post-firing and in the direct electrochemical conversion of coal-derived fuels for improved plant efficiency. The suitability of inorganic membrane materials for these purposes stems as much from thermal and chemical stability in coal plant operating conditions as from high performance in gas separations and power generation. Hydrophilic, micro-porous zeolite membrane structures are attractive for separating CO2 from N2 in gaseous waste streams due to the attraction of CO2 to the membrane surface and micropore walls that gives the advantage to CO2 transport. Recent studies have indicated that retention of the templating agent used in zeolite synthesis can further block N2 from the micropore interior and significantly improve CO2/N2 selectivity. However, the role of the templating agent in micro-porous transport has not been well investigated. In this work, gas sorption studies were conducted by high-pressure thermo-gravimetric analysis on Zeolite Y membrane materials to quantify the effect of the templating agent on CO2, N2, and H2O adsorption/desorption, as well as to examine the effect of humidification on overall membrane performance. In equilibrium conditions, the N2 sorption enthalpy was nearly unchanged by the presence of the templating agent, but the N2 pore occupation was reduced ˜1000x. Thus, the steric nature of the blocking of N2 from the micropores by the templating agent was confirmed. CO2 and H2O sorption enthalpies were similarly unaffected by the templating agent, and the micropore occupations were only reduced as much as the void volume taken up by the templating agent. Thus, the steric blocking effect did not occur for molecules more strongly attracted to the micropore walls. Additionally, in time-transient measurements the CO 2 and H2O mobilities were significantly enhanced by the presence

  17. PROTECTIVE CLOTHING BASED ON PERMSELECTIVE MEMBRANE AND CARBON ADSORPTION

    International Nuclear Information System (INIS)

    Wijmans, J.G.; Stull, J.O.

    2001-01-01

    The goal of this project was to develop chemical protective clothing for use by DOE decontamination and decommissioning workers that is sufficiently water vapor permeable to keep the workers cool, thereby enhancing their productivity. This report describes the results of Phase II of a two-phase project to complete development of the novel permselective material and to test protective clothing made from the fabric. In Phase I a novel material incorporating a nonporous hydrophilic polyvinylacohol (PVA) layer, which is water vapor permeable but relatively impermeable to organic vapors, was developed. The results of the Phase I tests showed that the chemical resistance of the MTR material is comparable to that of Saranex/Tyvek materials, and that the comfort properties are closer to those of Tyvek (as measured in terms of CLO and permeability). Chemical resistance was measured using permeation tests against liquid dichloromethane. Comfort properties were ascertained by measuring the water vapor transmission of the material and by sweating manikin tests on whole protective suits. In addition, a cost/benefit analysis demonstrated that use of MTR's material technology could result in significant improvements in work productivity and cost savings if protective clothing items made from the new material were used more than once. In Phase II, MTR undertook a program to optimize the performance and production engineering for the new material technology. A partnership was formed with Kimberly-Clark Corporation to assist with a detailed evaluation of the MTR technology, and MTR used the services of Mr. Jeff Stull, President of the consulting firm International Personnel Protection, Inc., who conducted a detailed economic and application analysis for the developed fabric. The protective fabric manufacturing steps were simplified significantly, resulting in a 30% reduction in manufacturing costs and eliminating the necessity for capital investment in production equipment. Protective suits were prepared in collaboration with Kimberly-Clark Corporation and heat stress testing with human test subjects was carried out by the International Union of Operating Engineers (IUOE). The tests confirmed that the MTR protective fabric is significantly more comfortable than non-breathable materials. A cost analysis was developed from the properties of the optimized protective fabric and the results of the of the IUOE field study to determine the potential for the MTR material technology within the chemical protective clothing market. A detailed assessment of the specific chemical protective clothing applications for which the material can be used and its competitiveness with existing material technology, based both on expected performance and material/end item costs, was prepared. Three specific market opportunities identified for the novel protective fabric are: (1) liquid splash protective clothing for hazardous waste site operations, (2) liquid splash protective clothing for emergency response, and (3) Class 3 NFPA 1994-compliant protective clothing for civilian use during chemical terrorism incidents

  18. PROTECTIVE CLOTHING BASED ON PERMSELECTIVE MEMBRANE AND CARBON ADSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Wijmans; J.O. Stull

    2001-11-07

    The goal of this project was to develop chemical protective clothing for use by DOE decontamination and decommissioning workers that is sufficiently water vapor permeable to keep the workers cool, thereby enhancing their productivity. This report describes the results of Phase II of a two-phase project to complete development of the novel permselective material and to test protective clothing made from the fabric. In Phase I a novel material incorporating a nonporous hydrophilic polyvinylacohol (PVA) layer, which is water vapor permeable but relatively impermeable to organic vapors, was developed. The results of the Phase I tests showed that the chemical resistance of the MTR material is comparable to that of Saranex/Tyvek materials, and that the comfort properties are closer to those of Tyvek (as measured in terms of CLO and permeability). Chemical resistance was measured using permeation tests against liquid dichloromethane. Comfort properties were ascertained by measuring the water vapor transmission of the material and by sweating manikin tests on whole protective suits. In addition, a cost/benefit analysis demonstrated that use of MTR's material technology could result in significant improvements in work productivity and cost savings if protective clothing items made from the new material were used more than once. In Phase II, MTR undertook a program to optimize the performance and production engineering for the new material technology. A partnership was formed with Kimberly-Clark Corporation to assist with a detailed evaluation of the MTR technology, and MTR used the services of Mr. Jeff Stull, President of the consulting firm International Personnel Protection, Inc., who conducted a detailed economic and application analysis for the developed fabric. The protective fabric manufacturing steps were simplified significantly, resulting in a 30% reduction in manufacturing costs and eliminating the necessity for capital investment in production equipment. Protective suits were prepared in collaboration with Kimberly-Clark Corporation and heat stress testing with human test subjects was carried out by the International Union of Operating Engineers (IUOE). The tests confirmed that the MTR protective fabric is significantly more comfortable than non-breathable materials. A cost analysis was developed from the properties of the optimized protective fabric and the results of the of the IUOE field study to determine the potential for the MTR material technology within the chemical protective clothing market. A detailed assessment of the specific chemical protective clothing applications for which the material can be used and its competitiveness with existing material technology, based both on expected performance and material/end item costs, was prepared. Three specific market opportunities identified for the novel protective fabric are: (1) liquid splash protective clothing for hazardous waste site operations, (2) liquid splash protective clothing for emergency response, and (3) Class 3 NFPA 1994-compliant protective clothing for civilian use during chemical terrorism incidents.

  19. Comparative removal of emerging contaminants from aqueous solution by adsorption on an activated carbon.

    Science.gov (United States)

    Gil, A; Taoufik, N; García, A M; Korili, S A

    2018-04-19

    Batch sorption experiments were performed to study the adsorption of six emerging pollutants from aqueous solutions using a commercial granular activated carbon as adsorbent. Caffeine, clofibric acid, diclofenac, gallic acid, ibuprofen and salicylic acid were selected as representative contaminants. The activated carbon was characterized by nitrogen adsorption at 77 K, and through the determination of point of zero charge. The effects of several operational parameters, such as pH, initial concentration of organic molecules, mass of adsorbent and contact time, on the sorption behaviour were evaluated. The contact time to attain equilibrium for maximum adsorption was found to be 40 min. The kinetic data were correlated to several adsorption models, and the adsorption mechanism found to follow pseudo-second-order and intraparticle-diffusion models with external mass transfer predominating in the first 15 min of the experiment. The equilibrium adsorption data were analysed using the Freundlich, Langmuir and Toth isotherm equation models. The similar chemical structure and molecular weight of the organic pollutants studied to make the adsorption capacity of the activated carbon used very similar for all the molecules.

  20. Adsorption of hexavalent chromium by polyacrylonitrile-based porous carbon from aqueous solution.

    Science.gov (United States)

    Feng, Bin; Shen, Wenzhong; Shi, Liyi; Qu, Shijie

    2018-01-01

    Owing to the unique microporous structure and high specific surface area, porous carbon could act as a good carrier for functional materials. In this paper, polyacrylonitrile (PAN)-based porous carbon materials (PPC-0.6-600, PPC-0.8-600, PPC-0.6-800 and PPC-0.8-800) were prepared by heating KOH at 600°C and 800 o C for the removal of Cr(VI) from aqueous solution. The adsorbent was characterized by the techniques of Fourier transform infrared spectroscopy (FT-IR), elementary analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N 2 adsorption techniques. The results showed that the adsorption capacity increased with decreasing pH value of the initial solution. The adsorption capacity of Cr(VI) on PPC-0.8-800 was much greater than that on other materials, and maximum adsorption capacity were calculated to be 374.90 mg g -1 . Moreover, PPC-0.8-800 had superior recyclability for the removal of Cr(VI) from wastewater, about 82% of its initial adsorption capacity was retained even after five cycles. The result of kinetic simulation showed that the adsorption of Cr(VI) on the PAN-based porous carbon could be described by pseudo-second-order kinetics. The adsorption process was the ionic interaction between protonated amine groups of PPC and HCrO 4 - ions.

  1. Adsorption of Cr(Ⅵ in wastewater using magnetic multi-wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Zhuo-nan Huang

    2015-07-01

    Full Text Available Magnetic multi-wall carbon nanotubes were prepared with wet chemical treatments and characterized by a transmission electron microscope (TEM and X-ray diffraction (XRD. They were used as adsorbents for the removal of Cr(Ⅵ in aqueous solutions. The effects of adsorbent dosage, the concentration of Cr(Ⅵ in aqueous solution, temperature, and pH value on the removal efficiency were studied. Results showed that the adsorption capacity of the magnetic multi-wall carbon nanotubes increased with the initial Cr(Ⅵ concentration, but decreased with the increase of adsorbent dosage. The adsorption amount increased with contact time. The adsorption kinetics were best represented by the pseudo second-order kinetic model, and the adsorption isotherms indicated that the Langmuir model better reflected the adsorption process. The obtained calculation results for the Gibbs free energy revealed that the adsorption was a spontaneous and endothermic process. The enthalpy deviation was 3.835 kJ·mol-1. The magnetic multi-wall carbon nanotubes showed significant potential for application in adsorption of heavy metal ions.

  2. Adsorption of Cr(VI in wastewater using magnetic multi-wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Zhuo-nan Huang

    2015-07-01

    Full Text Available Magnetic multi-wall carbon nanotubes were prepared with wet chemical treatments and characterized by a transmission electron microscope (TEM and X-ray diffraction (XRD. They were used as adsorbents for the removal of Cr(VI in aqueous solutions. The effects of adsorbent dosage, the concentration of Cr(VI in aqueous solution, temperature, and pH value on the removal efficiency were studied. Results showed that the adsorption capacity of the magnetic multi-wall carbon nanotubes increased with the initial Cr(VI concentration, but decreased with the increase of adsorbent dosage. The adsorption amount increased with contact time. The adsorption kinetics were best represented by the pseudo second-order kinetic model, and the adsorption isotherms indicated that the Langmuir model better reflected the adsorption process. The obtained calculation results for the Gibbs free energy revealed that the adsorption was a spontaneous and endothermic process. The enthalpy deviation was 3.835 kJ·mol−1. The magnetic multi-wall carbon nanotubes showed significant potential for application in adsorption of heavy metal ions.

  3. Study on adsorption of activated carbon fiber to background-level xenon in air by the method of 133Xe tracer

    International Nuclear Information System (INIS)

    Zhang Haitao; Wang Yalong; Zhang Lixing; Wang Xuhui; Zhang Xiaolin

    2001-01-01

    The adsorption behaviors of the different activated carbon fibers to ultra-trace xenon in air are studied using the method of 133 Xe as tracer. The efficiency equation of adsorption columns are determined. The comparison of adsorptive capacity between activated carbon fibers and activated carbon indicates that activated carbon fibers are better than activated carbon under low temperature

  4. Study of Hexane Adsorption on Activated Carbons with Differences in Their Surface Chemistry.

    Science.gov (United States)

    Hernández-Monje, Diana; Giraldo, Liliana; Moreno-Piraján, Juan Carlos

    2018-02-22

    The study of aliphatic compounds adsorption on activated carbon can be carried out from the energetic change involved in the interaction; the energy values can be determined from isotherms or by the immersion enthalpy. Vapor phase adsorption isotherms of hexane at 263 K on five activated carbons with different content of oxygenated groups and the immersion enthalpy of the activated carbons in hexane and water were determined in order to characterize the interactions in the solid-liquid system, and for calculating the hydrophobic factor of the activated carbons. The micropore volume and characteristic energy from adsorption isotherms of hexane, the BET (Brunauer-Emmett-Teller) surface area from the adsorption isotherms of N₂, and the area accessible to the hexane from the immersion enthalpy were calculated. The activated carbon with the lowest content of oxygenated groups (0.30 µmolg - ¹) and the highest surface area (996 m²g - ¹) had the highest hexane adsorption value: 0.27 mmol g - ¹; the values for E o were between 5650 and 6920 Jmol - ¹ and for ΔH im were between -66.1 and -16.4 Jg - ¹. These determinations allow us to correlate energetic parameters with the surface area and the chemical modifications that were made to the solids, where the surface hydrophobic character of the activated carbon favors the interaction.

  5. Adsorption of sulfur dioxide on ammonia-treated activated carbon fibers

    Science.gov (United States)

    Mangun, C.L.; DeBarr, J.A.; Economy, J.

    2001-01-01

    A series of activated carbon fibers (ACFs) and ammonia-treated ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore volume, and pore surface chemistry on adsorption of sulfur dioxide and its catalytic conversion to sulfuric acid. As expected, the incorporation of basic functional groups into the ACFs was shown as an effective method for increasing adsorption of sulfur dioxide. The adsorption capacity for dry SO2 did not follow specific trends; however the adsorption energies calculated from the DR equation were found to increase linearly with nitrogen content for each series of ACFs. Much higher adsorption capacities were achieved for SO2 in the presence of oxygen and water due to its catalytic conversion to H2SO4. The dominant factor for increasing adsorption of SO2 from simulated flue gas for each series of fibers studied was the weight percent of basic nitrogen groups present. In addition, the adsorption energies calculated for dry SO2 were shown to be linearly related to the adsorption capacity of H2SO4 from this flue gas for all fibers. It was shown that optimization of this parameter along with the pore volume results in higher adsorption capacities for removal of SO2 from flue gases. ?? 2001 Elsevier Science Ltd. All rights reserved.

  6. Adsorption of diuron and dichlobenil on multiwalled carbon nanotubes as affected by lead.

    Science.gov (United States)

    Chen, Guang-Cai; Shan, Xiao-Quan; Pei, Zhi-Guo; Wang, Huanhua; Zheng, Li-Rong; Zhang, Jing; Xie, Ya-Ning

    2011-04-15

    The effect of lead on the adsorption of diuron and dichlobenil on multiwalled carbon nanotubes (MWCNTs) was investigated to explore the possible application of MWCNTs for removal of both herbicides from contaminated water. The adsorption of diuron and dichlobenil on MWCNTs at pH 6 was nonlinear and fit the Polanyi-Manes model well. The adsorption of diuron and dichlobenil was closely correlated with specific surface areas and micropore volumes of MWCNTs. An increase in oxygen content of MWCNTs with same diameters and similar surface areas decreased the adsorption of diuron and dichlobenil, while increased the adsorption of lead. Micro-Fourier transform infrared spectroscopic study indicated that hydrogen bonding is a main mechanism responsible for the adsorption of diuron or dichlobenil onto MWCNTs-O. Oxygen containing groups, mainly carboxylic groups, significantly increased the adsorption of lead through the formations of outer-sphere and inner-sphere complexes, which are verified by X-ray absorption spectroscopic measurements. Oxygen containing groups and the presence of lead diminished the adsorption of diuron and dichlobenil. The suppression mechanisms of lead were ascribed to hydration and complexation of lead with carboxylic groups, which may occupy part of surface of MWCNTs-O. The large hydration shell of lead cations may intrude or shield hydrophobic and hydrophilic sites, resulting in a decreased adsorption of diuron and dichlobenil at the lead-complexed moieties. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Adsorption of ionizable organic contaminants on multi-walled carbon nanotubes with different oxygen contents

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaona; Zhao Huimin [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Liaoning Province, Dalian 116024 (China); Quan Xie, E-mail: quanxie@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Liaoning Province, Dalian 116024 (China); Chen Shuo; Zhang Yaobin; Yu Hongtao [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Liaoning Province, Dalian 116024 (China)

    2011-02-15

    Multi-walled carbon nanotubes (MWNTs), which are considered to be promising candidates for the adsorption of toxic organics, are released into aqueous environment with their increasing production and application. In this study, the adsorption behaviors of five structurally related ionizable organic contaminants namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonamide (PFOSA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-n-nonylphenol (4-NP) onto MWNTs with different oxygen contents (3.84-22.85%) were investigated. The adsorption kinetics was investigated and simulated with pseudo-second-order model. The adsorption isotherms were found to be fitted with Freundlich model and influenced by both the properties of organic chemicals and the oxygen contents of MWNTs. As adsorption capacity decreases dramatically with the increasing of oxygen contents, the MWNTs with the lowest oxygen contents possess the highest adsorption capacity among four MWNTs. For the MWNTs with the oxygen contents of 3.84%, the adsorption affinity related with hydrophobic interaction and {pi}-electron polarizability decreased in the order of 4-NP > PFOSA > PFOS > 2,4-D > PFOA. Furthermore, the adsorption characters of five contaminants were affected by solution pH and solute pK{sub a} considering electrostatic repulse force and hydrogen bonding, which showed the adsorption of MWNTs with lower oxygen content is much sensitive to solution chemistry.

  8. Adsorption of ionizable organic contaminants on multi-walled carbon nanotubes with different oxygen contents

    International Nuclear Information System (INIS)

    Li Xiaona; Zhao Huimin; Quan Xie; Chen Shuo; Zhang Yaobin; Yu Hongtao

    2011-01-01

    Multi-walled carbon nanotubes (MWNTs), which are considered to be promising candidates for the adsorption of toxic organics, are released into aqueous environment with their increasing production and application. In this study, the adsorption behaviors of five structurally related ionizable organic contaminants namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonamide (PFOSA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-n-nonylphenol (4-NP) onto MWNTs with different oxygen contents (3.84-22.85%) were investigated. The adsorption kinetics was investigated and simulated with pseudo-second-order model. The adsorption isotherms were found to be fitted with Freundlich model and influenced by both the properties of organic chemicals and the oxygen contents of MWNTs. As adsorption capacity decreases dramatically with the increasing of oxygen contents, the MWNTs with the lowest oxygen contents possess the highest adsorption capacity among four MWNTs. For the MWNTs with the oxygen contents of 3.84%, the adsorption affinity related with hydrophobic interaction and π-electron polarizability decreased in the order of 4-NP > PFOSA > PFOS > 2,4-D > PFOA. Furthermore, the adsorption characters of five contaminants were affected by solution pH and solute pK a considering electrostatic repulse force and hydrogen bonding, which showed the adsorption of MWNTs with lower oxygen content is much sensitive to solution chemistry.

  9. Membranes with functionalized carbon nanotube pores for selective transport

    Science.gov (United States)

    Bakajin, Olgica; Noy, Aleksandr; Fornasiero, Francesco; Park, Hyung Gyu; Holt, Jason K; Kim, Sangil

    2015-01-27

    Provided herein composition and methods for nanoporous membranes comprising single walled, double walled, or multi-walled carbon nanotubes embedded in a matrix material. Average pore size of the carbon nanotube can be 6 nm or less. These membranes are a robust platform for the study of confined molecular transport, with applications in liquid and gas separations and chemical sensing including desalination, dialysis, and fabric formation.

  10. Enhanced mitigation of para-chlorophenol using stratified activated carbon adsorption columns.

    Science.gov (United States)

    Sze, Michael Fan Fu; McKay, Gordon

    2012-03-01

    The adsorptive removal of toxic para-chlorophenol using activated carbon adsorption columns is a proven effective engineering process. This paper examined the possibility to stratify an adsorbent bed into layers, in order to enhance the adsorption process performance in terms of increased column service time and adsorbent bed saturation. Four different types of fixed-bed adsorption columns are used and compared under the same operating conditions, but with the variation of column geometry and activated carbon particle size stratification. The Type 3 column - a cylindrical column with particle stratification packing, is found to be the most efficient choice, as the extent of column service time and adsorbent bed saturation are the largest. This could eventually decrease the frequency of adsorbent replacement/regeneration and hence reduce the operating cost of the fixed-bed adsorption process. The Homogeneous Surface Diffusion Model (HSDM) was applied successfully to describe the dynamic adsorption of para-chlorophenol onto Filtrasorb 400 (F400) activated carbon in different types of columns. The Redlich-Peterson isotherm model equation, an experimentally derived external mass transfer correlation and a constant surface diffusivity are used in the HSDM. The optimised surface diffusivity of para-chlorophenol is found to be 1.20E-8 cm(2)/s, which is in good agreement with other phenolics/F400 carbon diffusing systems in literature. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Effect of Solution pH on the Adsorption of Paracetamol on Chemically Modified Activated Carbons.

    Science.gov (United States)

    Bernal, Valentina; Erto, Alessandro; Giraldo, Liliana; Moreno-Piraján, Juan Carlos

    2017-06-22

    Paracetamol adsorption in acidic, neutral and basic media on three activated carbons with different chemistry surfaces was studied. A granular activated carbon (GAC) was prepared from coconut shell; starting from this sample, an oxidized activated carbon (GACo) was obtained by treating the GAC with a boiling solution of 6 M nitric acid, so to generate a greater number of oxygenated surface groups. In addition, a reduced activated carbon (GACr) was obtained by heating the GAC at 1173 K, to remove the oxygenated surface groups. Paracetamol adsorption was higher for GACr due to the lower presence of oxygenated surface functional groups. Moreover, adsorption was highest at neutral pH. The magnitude of the interactions between paracetamol molecules and activated carbons was studied by measuring the immersion enthalpies of activated carbons in solution of paracetamol at different concentrations and pH values and by calculating the interaction enthalpy. The highest value was obtained for GACr in a paracetamol solution of 1000 mg L -1 at pH 7, confirming that paracetamol adsorption is favoured on basic activated carbons at pH values near to neutrality. Finally, the Gibbs energy changes confirmed the latter result, allowing explaining the different magnitudes of the interactions between paracetamol and activated carbons, as a function of solution pH.

  12. Effect of Solution pH on the Adsorption of Paracetamol on Chemically Modified Activated Carbons

    Directory of Open Access Journals (Sweden)

    Valentina Bernal

    2017-06-01

    Full Text Available Paracetamol adsorption in acidic, neutral and basic media on three activated carbons with different chemistry surfaces was studied. A granular activated carbon (GAC was prepared from coconut shell; starting from this sample, an oxidized activated carbon (GACo was obtained by treating the GAC with a boiling solution of 6 M nitric acid, so to generate a greater number of oxygenated surface groups. In addition, a reduced activated carbon (GACr was obtained by heating the GAC at 1173 K, to remove the oxygenated surface groups. Paracetamol adsorption was higher for GACr due to the lower presence of oxygenated surface functional groups. Moreover, adsorption was highest at neutral pH. The magnitude of the interactions between paracetamol molecules and activated carbons was studied by measuring the immersion enthalpies of activated carbons in solution of paracetamol at different concentrations and pH values and by calculating the interaction enthalpy. The highest value was obtained for GACr in a paracetamol solution of 1000 mg L−1 at pH 7, confirming that paracetamol adsorption is favoured on basic activated carbons at pH values near to neutrality. Finally, the Gibbs energy changes confirmed the latter result, allowing explaining the different magnitudes of the interactions between paracetamol and activated carbons, as a function of solution pH.

  13. Adsorption Of Blue-Dye On Activated Carbons Produced From Rice ...

    African Journals Online (AJOL)

    The activated carbons prepared were used for the adsorption of blue-dye of concentration ranging from 100 to 2000 mg/l from aqueous solution. The results obtained indicated that ferric chloride-activated carbons produced from coconut coirpith are better adsorbents for blue-dye than those prepared from rice husk.

  14. Enhancing adsorption efficiency of dichloroacetic acid onto mesoporous carbons: Procedure optimization, mechanism and characterization.

    Science.gov (United States)

    Ding, Ying; Zhu, Jianzhong; Ji, Dongliang; Cao, Yang; Ling, Xiaojia; Chen, Wei

    2015-08-15

    Highly ordered mesoporous carbon may be directly synthesized via supramolecular self-assembly with in situ evaporation-induced crystallization process by controlling thermal reaction temperatures and carbon mass loading. In the present study, the effects of thermal reaction temperatures on the structural characterization and adsorption capacity of mesoporous carbon have been investigated and analyzed with orthogonal test experiments. The results show the carbonization temperature (R=32.1) plays a more important role than the self-assembly temperature (R=8.5) and thermal polymerization temperature (R=10.1) in manipulating the pore texture structures. The optimization grouping temperature was 40-110-500 °C. The optimum mesoporous carbon sample had the highest BET specific surface area (474 m(2)/g), the largest pore volume (0.46 cm(3)/g), and with reasonable uniform pore size distribution. The adsorption evaluation also shows the adsorption capacity is strongly correlated with the pore structure of mesoporous carbon, the optimized mesoporous carbon sample displayed the largest adsorption capacity (350 mg/g) at an initial concentration of 20.0 mg/L of dichloroacetic acid. The study results indicate optimization of thermal reaction parameters is an effective approach for synthesis of ordered mesoporous carbons. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Adsorption Studies of Coconut Shell Carbons Prepared by KOH Activation for Removal of Lead(II From Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Chengwen Song

    2013-12-01

    Full Text Available Removal of Pb2+ from aqueous solutions using coconut shell carbons produced by KOH activation is performed in this paper. Morphology and pore structure characteristic of coconut shell carbons are analyzed by SEM and nitrogen adsorption techniques. Effects of adsorbent concentration, agitation time and initial ion concentration on the adsorption behavior are investigated, and adsorption isotherm and kinetics on coconut shell carbons are also studied. The results show that high weight ratio of KOH/sample is favorable to produce rich porous structure. The resultant coconut shell carbons with a high specific surface area of 1135 m2/g is obtained and demonstrates good adsorption potential on removal of Pb2+ from aqueous solutions. Adsorption data fit well with Freundlich and Halsey isotherms. The kinetic studies indicate that adsorption behavior can be described by pseudo-second-order kinetic model, which also follows external diffusion and intra-particle diffusion in the adsorption process.

  16. Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2 Adsorption Membrane

    Science.gov (United States)

    Wahiduzzaman; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

    2017-01-01

    We report the sonochemical synthesis of MOF (metal organic framework) nanoparticles of 30-200 nm in size and electrospraying of those particles on electrospun nanofibers to process a MOF-attached nanofibrous membrane. This membrane displayed significant selectivity towards CO2 and capacity of adsorbing with 4000-5000 ppm difference from a mixed gas flow of 1% CO2 and 99% N2. Applying ultrasonic waves during the MOF synthesis offered rapid dispersion and formation of crystalline MOF nanoparticles in room temperature. The MOF nanoparticles of 100-200 nm in size displayed higher surface area and adsorption capacity comparing to that of 30-60 nm in size. Nanofibrous membrane was produced by electrospinning of MOF blended PAN solution followed by electrospraying of additional MOF nanoparticles. This yielded uniform MOF deposition on nanofibers, occurred due to electrostatic attraction between highly charged nanoparticles and conductive nanofibers. A test bench for real-time CO2 adsorption at room temperature was built with non-dispersive Infrared (NDIR) CO2 sensors. Comparative tests were performed on the membrane to investigate its enhanced adsorption capacity. Three layers of the as-produced membranes displayed CO2 adsorption for approximately 2 h. Thermogravimetric analysis (TGA) of the membrane showed the thermal stability of the MOF and PAN up to 290 and 425 °C, respectively.

  17. Phenolic resin-based porous carbons for adsorption and energy storage applications

    Science.gov (United States)

    Wickramaratne, Nilantha P.

    The main objective of this dissertation research is to develop phenolic resin based carbon materials for range of applications by soft-templating and Stober-like synthesis strategies. Applications Studied in this dissertation are adsorption of CO2, bio-molecular and heavy metal ions, and energy storage devices. Based on that, our goal is to design carbon materials with desired pore structure, high surface area, graphitic domains, incorporated metal nanoparticles, and specific organic groups and heteroatoms. In this dissertation the organic-organic self-assembly of phenolic resins and triblock copolymers under acidic conditions will be used to obtain mesoporous carbons/carbon composites and Stober-like synthesis involving phenolic resins under basic condition will be used to prepare polymer/carbon particles and their composites. The structure of this dissertation consists of an introductory chapter (Chapter 1) discussing the general synthesis of carbon materials, particularly the soft-templating strategy and Stober-like carbon synthesis. Also, Chapter 1 includes a brief outline of applications namely adsorption of CO2, biomolecule and heavy metal ions, and supercapacitors. Chapter 2 discusses the techniques used for characterization of the carbon materials studied. This chapter starts with nitrogen adsorption analysis, which is used to measure the specific surface area, pore volume, distribution of pore sizes, and pore width. In addition to nitrogen adsorption, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution thermogravimetric analysis (HR-TGA), cyclic voltammetry (CV) and CHNS elemental analysis (EA) are mentioned too. Chapter 3 is focused on carbon materials for CO2 adsorption. There are different types of porous solid materials such as silicate, MOFs, carbons, and zeolites studied for CO2 adsorption. However, the carbon based materials are considered to be the best candidates for CO 2 adsorption to the industrial point of

  18. Adsorption of diclofenac and nimesulide on activated carbon: Statistical physics modeling and effect of adsorbate size

    Science.gov (United States)

    Sellaoui, Lotfi; Mechi, Nesrine; Lima, Éder Cláudio; Dotto, Guilherme Luiz; Ben Lamine, Abdelmottaleb

    2017-10-01

    Based on statistical physics elements, the equilibrium adsorption of diclofenac (DFC) and nimesulide (NM) on activated carbon was analyzed by a multilayer model with saturation. The paper aimed to describe experimentally and theoretically the adsorption process and study the effect of adsorbate size using the model parameters. From numerical simulation, the number of molecules per site showed that the adsorbate molecules (DFC and NM) were mostly anchored in both sides of the pore walls. The receptor sites density increase suggested that additional sites appeared during the process, to participate in DFC and NM adsorption. The description of the adsorption energy behavior indicated that the process was physisorption. Finally, by a model parameters correlation, the size effect of the adsorbate was deduced indicating that the molecule dimension has a negligible effect on the DFC and NM adsorption.

  19. Effect of Ultrasound on Bisphenol A Adsorption on the Granular Activated Carbon

    Science.gov (United States)

    Myunghee Lim,; Younggyu Son,; Mingcan Cui,; Jeehyeong Khim,

    2010-07-01

    The aim of this study is to investigate the effects of ultrasound (power, frequency) on bisphenol A (BPA) adsorption on granular activated carbon (GAC). The result of adsorption isotherm in a BPA solution, using sonicated GAC (at 35 kHz) can more successfully adsorb BPA than sonicated GAC (at 300 kHz) and the original GAC. At low frequency GAC has a high cavitation effect. Therefore, the amount of adsorbed BPA at a low frequency was higher than at a high frequency. In isotherm experiments, ultrasound can enhance the adsorption process in GAC in both frequencies (35 and 300 kHz). These results agree with other previous researches. The effect of power intensity in the adsorption of BPA is increased the adsorption of BPA with increasing power. The optimum power exists and differs from frequencies because the cavitation effect is not the same with different frequencies.

  20. Experimental study on adsorption kinetics of activated carbon/R134a and activated carbon/R507A pairs

    Energy Technology Data Exchange (ETDEWEB)

    Habib, Khairul; Koyama, Shigeru [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga-shi, Fukuoka 816-8580 (Japan); Saha, Bidyut B. [Mechanical Engineering Department, Kyushu University, 744 Motooka, Fukuoka-shi, Fukuoka 819-0395 (Japan); Rahman, Kazi A.; Chakraborty, Anutosh; Ng, Kim Choon [Mechanical Engineering Department, National University of Singapore, 10 Kent Ridge Crescent (Singapore)

    2010-06-15

    The objective of this article is to evaluate adsorption kinetics of R134a and R507A on pitch based activated carbon experimentally by a constant volume variable pressure method at different adsorption temperatures ranging from 20 to 60 C. These data are useful for the design of adsorption cooling and refrigeration systems and are unavailable in the literature. Data obtained from the kinetic studies were analyzed with various kinetic models and the Fickian diffusion model is found to be the most suitable overall. Guided by the experimental measurements, the surface diffusion is also estimated and is found that it follows the classical Arrhenius law within the experimental range. (author)

  1. Adsorption of Malachite Green Dye by Acid Activated Carbon - Kinetic, Thermodynamic and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    P. K. Baskaran

    2011-01-01

    Full Text Available The ability of zea mays dust carbon to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Thermodynamic parameters such as ΔH°,ΔS° and ΔG°, were calculated from the slope and intercept of the linear plots. Analysis of adsorption results obtained at 303, 313, 323 and 333 K showed that the adsorption pattern on zea mays dust carbon seems to follow the Langmuir and Freundlich. The numerical values of sorption free energy indicate physical adsorption. The kinetic data indicated an intra-particle diffusion process with sorption being first order. The concentration of malachite green oxalate was measured before and after adsorption by using UV-visible spectrophotometer.

  2. Removal of nitrate from water by adsorption onto zinc chloride treated activated carbon

    DEFF Research Database (Denmark)

    Bhatnagar, A.; Ji, M.; Choi, Y.H.

    2008-01-01

    Adsorption study with untreated and zinc chloride (ZnCl2) treated coconut granular activated carbon (GAC) for nitrate removal from water has been carried out. Untreated coconut GAC was treated with ZnCl2 and carbonized. The optimal conditions were selected by studying the influence of process...... variables such as chemical ratio and activation temperature. Experimental results reveal that chemical weight ratio of 200% and temperature of 500 degrees C was found to be optimum for the maximum removal of nitrate from water. Both untreated and ZnCl2 treated coconut GACs were characterized by scanning...... electron microscopy (SEM), Brunauer Emmett Teller (BET) N-2-gas adsorption, surface area and Energy Dispersive X-Ray (EDX) analysis. The comparison between untreated and ZnCl2 treated GAC indicates that treatment with ZnCl2 has significantly improved the adsorption efficacy of untreated GAC. The adsorption...

  3. Adsorption Of Metamizole Sodium By Activated Carbon In Simulated Gastric And Intestinal Fluids

    Directory of Open Access Journals (Sweden)

    Elif Çalışkan Salihi

    2017-12-01

    Full Text Available In vitro adsorption of metamizole sodium by activated carbon was studied at pH 1.2 and 7.5 in order to simulate gastric and intestinal fluids. In the first 5 minutes, more than eighty percent of the total adsorption occurred but the adsorption process achieved to the equilibrium in 1 hour. Time to reach equilibrium was not changed with the changing pH, the concentration of the adsorbate or the adsorbent amount. The equilibrium data followed the Langmuir model and therefore fitted to L-type in accordance with the Giles classification for adsorption isotherms. The maximum removal capacities of the activated carbon for metamizole sodium were calculated using Langmuir equation and found as 185.19 mg/g and 161.29 mg/g at pH 1.2 and 7.5, respectively.

  4. Ceramic Membrane combined with Powdered Activated Carbon (PAC) or Coagulation for Treatment of Impaired Quality Waters

    KAUST Repository

    Hamad, Juma Z.

    2013-08-29

    Ceramic membranes (CM) are robust membranes attributed with high production, long life span and stability against critical conditions. While capital costs are high, these are partially offset by lower operation and maintenance costs compared to polymeric membranes. Like any other low-pressure membrane (LPM), CM faces problems of fouling, low removal of organic matter and poor removal of trace organic compounds (TOrCs). Current pretreatment approaches that are mainly based on coagulation and adsorption can remove some organic matter but with a low removal of the biopolymers component which is responsible for fouling. Powdered activated carbon (PAC) accompanied with a LPM maintains good removal of TOrCs. However, enhanced removal of TOrCs to higher level is required. Submicron powdered activated carbon (SPAC), obtained after crushing commercial activated carbon into very fine particle, and novel activated carbon (KCU 6) which is characterized with larger pores and high surface area were employed. A pre-coating approach, which provides intimated contact between PAC and contaminants, was adopted for wastewater and (high DOC) surface water treatment. For seawater, in-line coagulation with iron III chloride was adopted. Both SPAC and KCU 6 showed good removal of biopolymers at a dose of 30 mg/L with > 85 % and 90 %, respectively. A dose of 40 mg/L of SPAC and 30 mg/L KCU 6 pre-coats were successful used in controlling membrane fouling. SPAC is suggested to remove biopolymers by physical means and adsorption while KCU 6 removed biopolymers through adsorption. Both KCU 6 and SPAC attained high removal of TOrCs whereas KCU 6 showed outstanding performance. Out of 29 TOrCs investigated, KCU 6 showed > 87 % TOrCs rejection for 28 compounds. In seawater pretreatment, transparent exopolymer particles (TEP) were found to be an important foulant. TEP promoted both reversible and irreversible fouling. TEP are highly electronegative while alumina CM is positively charged which

  5. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    Science.gov (United States)

    Yoosefian, Mehdi

    2017-01-01

    Density functional studies on the adsorption behavior of nitrous oxide (N2O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N2O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N2O onto CNT, the horizontal adsorption with Eads = -0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N2O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N2O were investigated. Adsorption of N2O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N2O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N2O sensors.

  6. Experimental Study on Treatment of Dyeing Wastewater by Activated Carbon Adsorption, Coagulation and Fenton Oxidation

    Science.gov (United States)

    Xiaoxu, SUN; Jin, XU; Xingyu, LI

    2017-12-01

    In this paper dyeing waste water was simulated by reactive brilliant blue XBR, activated carbon adsorption process, coagulation process and chemical oxidation process were used to treat dyeing waste water. In activated carbon adsorption process and coagulation process, the water absorbance values were measured. The CODcr value of water was determined in Fenton chemical oxidation process. Then, the decolorization rate and COD removal rate were calculated respectively. The results showed that the optimum conditions of activated carbon adsorption process were as follows: pH=2, the dosage of activated carbon was 1.2g/L, the adsorption reaction time was 60 min, and the average decolorization rate of the three parallel experiments was 85.30%. The optimum conditions of coagulation experiment were as follows: pH=8~9, PAC dosage was 70mg/L, stirring time was 20min, standing time was 45min, the average decolorization rate of the three parallel experiments was 74.48%. The optimum conditions for Fenton oxidation were Fe2+ 0.05g/L, H2O2 (30%) 14mL/L, pH=3, reaction time 40min. The average CODcr removal rate was 69.35% in three parallel experiments. It can be seen that in the three methods the activated carbon adsorption treatment of dyeing wastewater was the best one.

  7. Adsorption Studies of Chromium(VI) on Activated Carbon Derived from Mangifera indica (Mango) Seed Shell

    Science.gov (United States)

    Mise, Shashikant; Patil, Trupti Nagendra

    2015-09-01

    The removal of chromium(VI) from synthetic sample by adsorption on activated carbon prepared from Mangifera indica (mango) seed shell have been carried out at room temperature 32 ± 1 °C. The removal of chromium(VI) from synthetic sample by adsorption on two types of activated carbon, physical activation and chemical activation (Calcium chloride and Sodium chloride), Impregnation Ratio's (IR) 0.25, 0.50, 0.75 for optimum time, optimum dosages and variation of pH were studied. It is observed that contact time differs for different carbons i.e. for physically and chemically activated carbons. The contact time decreases for chemically activated carbon compared to the physically activated carbon. It was observed that as dosage increases the adsorption increased along with the increase in impregnation ratio. It was also noted that as I.R. increases the surface area of Mangifera indica shell carbon increased. These dosage data were considered in the construction of isotherms and it was found that adsorption obeys Freundlich Isotherm and does not obey Langmuir Isotherm. The maximum removal of chromium (VI) was obtained in highly acidic medium at a pH of 1.50.

  8. Liquid-phase adsorption of phenols using activated carbons derived from agricultural waste material

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kunwar P. [Environmental Chemistry Section, Industrial Toxicology Research Centre, Post Box 80, MG Marg, Lucknow 226001 (India)], E-mail: kpsingh_52@yahoo.com; Malik, Amrita [Environmental Chemistry Section, Industrial Toxicology Research Centre, Post Box 80, MG Marg, Lucknow 226001 (India); Sinha, Sarita [National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001 (India); Ojha, Priyanka [Environmental Chemistry Section, Industrial Toxicology Research Centre, Post Box 80, MG Marg, Lucknow 226001 (India)

    2008-02-11

    Physical and chemical properties of activated carbons prepared from coconut shells (SAC and ATSAC) were studied. The adsorption equilibria and kinetics of phenol and 2,4-dichlorophenol from aqueous solutions on such carbons were then examined at three different temperatures (10, 25 and 40 deg. C). Adsorption of both phenol and 2,4-dichlorophenol increased with an increase in temperature. The experimental data were analyzed using the Langmuir and Freundlich isotherm models. Both the isotherm models adequately fit the adsorption data for both the phenols. The carbon developed through the acid treatment of coconut shells (ATSAC) exhibited relatively higher monolayer adsorption capacity for phenol (0.53 mmol g{sup -1}) and 2,4-dichlorophenol (0.31 mmol g{sup -1}) as compared to that developed by thermal activation (SAC) with adsorption capacity of 0.36 and 0.20 mmol g{sup -1}, for phenol and 2,4-dichlorophenol, respectively. The equilibrium sorption and kinetics model parameters and thermodynamic functions were estimated and discussed. The thermodynamic parameters (free energy, enthalpy and entropy changes) exhibited the feasibility and spontaneous nature of the adsorption process. The sorption kinetics was studied using the pseudo-first-order and second-order kinetics models. The adsorption kinetics data for both the phenol and 2,4-dichlorophenol fitted better to the second-order model. An attempt was also made to identify the rate-limiting step involved in the adsorption process. Results of mass transfer analysis suggested the endothermic nature of the reaction and change in the mechanism with time and initial concentration of the adsorbate. The results of the study show that the activated carbons derived from coconut shells can be used as potential adsorbent for phenols in water/wastewater.

  9. A review of functionalized carbon nanotubes and graphene for heavy metal adsorption from water: Preparation, application, and mechanism.

    Science.gov (United States)

    Xu, Jiang; Cao, Zhen; Zhang, Yilin; Yuan, Zilin; Lou, Zimo; Xu, Xinhua; Wang, Xiangke

    2018-03-01

    Carbon-based nanomaterials, especially carbon nanotubes and graphene, have drawn wide attention in recent years as novel materials for environmental applications. Notably, the functionalized derivatives of carbon nanotubes and graphene with high surface area and adsorption sites are proposed to remove heavy metals via adsorption, addressing the pressing pollution of heavy metal. This critical revies assesses the recent development of various functionalized carbon nanotubes and graphene that are used to remove heavy metals from contaminated water, including the preparation and characterization methods of functionalized carbon nanotubes and graphene, their applications for heavy metal adsorption, effects of water chemistry on the adsorption capacity, and decontamination mechanism. Future research directions have also been proposed with the goal of further improving their adsorption performance, the feasibility of industrial applications, and better simulating adsorption mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Electron Localization States in Asymmetric Shape Carbon Nanotubes Caused by Hydrogen Adsorption

    Science.gov (United States)

    Pan, L. J.; Chen, W. G.

    2017-12-01

    In this paper, we presented pseudopotential-based density functional theory studies on energy, structure, energy band structure of hydrogenated single-walled carbon nanotube. The stability of the configuration mainly depends on hydrogen coverage. According to the adsorption energies, the stability deteriorates with the increase of the hydrogen adsorption. The cross section of configurations become various shapes such as “beetle” or “lip” appearance without the balanced effects of hydrogen atoms. We also explored the energy band structures of configurations in three typical adsorption patterns, showing that the disparate trends of energy band gap as the hydrogen atoms concentrate. For C32H24, the band gap may reach the large value of 2.79 eV for the adsorption pattern A configuration and reduce to be zero for the adsorption pattern C case, the values of band gap for pattern A configurations decrease, which is opposite of the pattern B configurations as the adsorption hydrogen becomes more disperse. It is deduced that the hydrogen adsorption has significant effect on the electrical properties of the carbon nanotube.

  11. Adsorption mechanism of 2,4-dichlorophenoxyacetic acid onto nitric-acid-modified activated carbon fiber.

    Science.gov (United States)

    Li, Qun; Sun, Jie; Ren, Tianhao; Guo, Lin; Yang, Zhilin; Yang, Qi; Chen, Hai

    2018-04-01

    Adsorption by carbon materials is one of the relatively fast methods in present research, which is widely used in emergency events. Activated carbon fiber (ACF) modified by nitric acid (N-ACF) was studied in this research to determine the adsorption performance for 2,4-dichlorophenoxyacetic acid (2,4-D). Subsequently, influence factors, adsorption isotherm models, kinetics and thermodynamic were investigated in a batch system to realize this adsorption. Experimental results showed that ACF modified by 0.1M nitric acid had a better removal ability than 2,4-D. Removal rate of 2,4-D by N-ACF was greatly influenced by pH with the optimum pH at 2. The superiority of the Langmuir isotherm model in describing the adsorption equilibrium was revealed by correlation coefficients R2 (R 2  ≥ 0.997). Furthermore, adsorption kinetics was well described by pseudo-second-order model. The results of thermodynamic showed that adsorption was a spontaneous, endothermic process with randomness increasing. Additionally, surface structure properties of adsorbent were characterized by Scanning electron microscopy, Fourier transform infrared spectroscopy, Specific surface area analysis of Brunauer, Emmett and Teller and Boehm's titration. It turned out that the micropore structure and functional groups on N-ACF all can contribute to the removal of 2,4-D.

  12. Engineering design and theoretical analysis of nanoporous carbon membranes for gas separation

    Science.gov (United States)

    Acharya, Madhav

    1999-11-01

    Gases are used in a direct or indirect manner in virtually every major industry, such as steel manufacturing, oil production, foodstuffs and electronics. Membranes are being investigated as an alternative to established methods of gas separation such as pressure swing adsorption and cryogenic distillation. Membranes can be used in continuous operation and work very well at ambient conditions, thus representing a tremendous energy and economic saving over the other technologies. In addition, the integration of reaction and separation into a single unit known as a membrane reactor has the potential to revolutionize the chemical industry by making selective reactions a reality. Nanoporous carbons are highly disordered materials obtained from organic polymers or natural sources. They have the ability to separate gas molecules by several different mechanisms, and hence there is a growing effort to form them into membranes. In this study, nanoporous carbon membranes were prepared on macroporous stainless steel supports of both tubular and disk geometries. The precursor used was poly(furfuryl alcohol) and different synthesis protocols were employed. A spray coating method also was developed which allowed reproducible synthesis of membranes with very few defects. High gas selectivities were obtained such as O2/N2 = 6, H2/C2H 4 = 70 and CO2/N2 = 20. Membranes also were characterized using SEM and AFM, which revealed thin layers of carbon that were quite uniform and homogeneous. The simulation of nanoporous carbon structures also was carried out using a simple algorithmic approach. 5,6 and 7-membered rings were introduced into the structure, thus resulting in considerable curvature. The density of the structures were calculated and found to compare favorably with experimental findings. Finally, a theoretical analysis of size selective transport was performed using transition state theory concepts. A definite correlation of gas permeance with molecular size was obtained after

  13. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

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

  14. Very short functionalized carbon nanotubes for membrane applications

    NARCIS (Netherlands)

    Fonseca, A.; Reijerkerk, Sander; Potreck, Jens; Nijmeijer, Dorothea C.; Mekhalif, Z.; Delhalle, J.

    2010-01-01

    The cutting and functionalization of carbon nanotubes is described, applying a single-step ball-mill based process. Very short carbon nanotubes bearing primary amine functions were produced, characterized and incorporated in polymeric membranes. The gas separation performance of the composite

  15. Single and competitive adsorption of OMPs by carbon nanotubes - mechanism and fitting models

    Science.gov (United States)

    Kamińska, Gabriela; Dudziak, Mariusz; Bohdziewicz, Jolanta; Kudlek, Edyta

    2017-11-01

    The adsorption of three organic micropollutants (diclofenac - DFN, pentachlorophenol - PCP and octylphenol - OP) on two kinds of carbon nanotubes (single walled carbon nanotubes - SWCNT and single walled carbon nanotubes with amine group - SWCNT-NH2) was investigated, in single and bicomponent solution at pH 5. SWCNT-NH2 had three times lower specific surface area than SWCNT. Significant differences were observed in sorption capacity of SWCNT and SWCNT-NH2 for given chemicals. The sorption uptake changes in the following order: OP > PCP > DFN for SWCNT and DFN > PCP > OP for SWCNT-NH2. A few times higher adsorption of OP on SWCNT came from low OP solubility in water in comparison to PCP and DFN. While, higher adsorption of DFN and PCP on SWCNT-NH2 was a result of electrostatic attraction between dissociated form of these chemicals and positively charged SWCNT-NH2 at pH 5. In adsorption from bicomponent solution, significant competition was observed between PCP and DFN due to similar adsorption mechanism on SWCNT-NH2. Opposite tendency was observed for SWCNT, DFN did not greatly affect adsorption of PCP and OP since they were very easily absorbable by sigma-sigma interaction.

  16. Single and competitive adsorption of OMPs by carbon nanotubes – mechanism and fitting models

    Directory of Open Access Journals (Sweden)

    Kamińska Gabriela

    2017-01-01

    Full Text Available The adsorption of three organic micropollutants (diclofenac – DFN, pentachlorophenol – PCP and octylphenol – OP on two kinds of carbon nanotubes (single walled carbon nanotubes – SWCNT and single walled carbon nanotubes with amine group – SWCNT-NH2 was investigated, in single and bicomponent solution at pH 5. SWCNT-NH2 had three times lower specific surface area than SWCNT. Significant differences were observed in sorption capacity of SWCNT and SWCNT-NH2 for given chemicals. The sorption uptake changes in the following order: OP > PCP > DFN for SWCNT and DFN > PCP > OP for SWCNT-NH2. A few times higher adsorption of OP on SWCNT came from low OP solubility in water in comparison to PCP and DFN. While, higher adsorption of DFN and PCP on SWCNT-NH2 was a result of electrostatic attraction between dissociated form of these chemicals and positively charged SWCNT-NH2 at pH 5. In adsorption from bicomponent solution, significant competition was observed between PCP and DFN due to similar adsorption mechanism on SWCNT-NH2. Opposite tendency was observed for SWCNT, DFN did not greatly affect adsorption of PCP and OP since they were very easily absorbable by sigma-sigma interaction.

  17. Removal of Trichloroethylene from Water by Adsorption on to Multiwall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    S. Nasseri

    2011-10-01

    Full Text Available Groundwater recourses may be contaminated with trichloroethylene (TCE which is used in electronic, electric, dry cleaning and other similar industries and often treated by air stripping, which TCE in its vapor form is stripped from groundwater by air and is emitted into the atmosphere without any additional treatments. Carbon nanotubes are expected to play an important role in sensing, pollution treatment and separation techniques. In this study adsorption of trichloroethylene on multiwall carbon nanotubes has been investigated. The effect of contact time, pH, initial concentration of trichloroethylene and temperature on its adsorption were investigated. Adsorption isotherms and related constants were also determined. Results showed that contact times to reach equilibrium changed from 30 min (for 150 μg/L initial concentration to 10 min (for 600 μg/L concentrations at 25 °C; the equilibrium times in 40°C were 40 min and 15 min, respectively. Multi-wall carbon nanotubes showed to act as a good adsorbent for TCE in a wide range of pH=(3-9. For pH>9, adsorption decreased due to ionization of oxygen-containing groups. Adsorption test results revealed that TCE adsorption on the studied adsorbents could be better described by Freundlich isotherm.

  18. Adsorption of ofloxacin and norfloxacin on carbon nanotubes: Hydrophobicity- and structure-controlled process

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hongbo [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Pan, Bo, E-mail: panbocai@gmail.com [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Wu, Min; Liu, Ying; Zhang, Di [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Xing, Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer A significant relationship between K{sub d} and SSA for both OFL and NOR on CNTs. Black-Right-Pointing-Pointer No relationship was observed between K{sub d}s and oxygen content of CNTs. Black-Right-Pointing-Pointer Normalizing K{sub d}s by solubilites enlarged OFL and NOR sorption difference. Black-Right-Pointing-Pointer OFL and NOR sorption was controlled by their structural- and hydrophobic-properties. - Abstract: Adsorption of antibiotics on solid particles is a key process controlling their fate in the subsurface. This study compared the adsorption of ofloxacin and norfloxacin (NOR) on carbon nanotubes (CNTs) to evaluate the role of structural and hydrophobic properties in regulating their adsorption. A significant relationship was observed between single-point adsorption coefficients (K{sub d}) and specific surface area (highly hydrophobic), but not between K{sub d}s and oxygen content. This result suggested that site-specific adsorption was not important but hydrophobic effect may have an important contribution to OFL and NOR adsorption on CNTs. However, normalizing the adsorption coefficients by OFL and NOR solubilities enlarged their adsorption difference indicating that hydrophobicity was not the only factor controlling the difference between OFL and NOR adsorption on CNTs. Their chemical structures show that both chemicals could interact with CNTs through an electron-donor-acceptor mechanism. This mechanism was correlated with the different adsorption of OFL and NOR on functionalized CNTs (namely hydroxylized, carboxylized, and graphitized CNTs). This study revealed that OFL and NOR adsorption was controlled by their both structural- and hydrophobic-properties.

  19. Preparing activated carbon from charcoal and investigation of the selective uranium adsorption

    International Nuclear Information System (INIS)

    Kuetahyali, C.; Eral, M.

    2001-01-01

    Preconcentration and separation procedures based on adsorption phenomena are important in nuclear and especially radiation chemistry, industry, medicine and daily life. Adsorption of uranium onto various solids is important from purification, environmental and radioactive waste disposal points of view . The treatment of aqueous nuclear waste solutions containing soluble metal ions requires concentration of the metal ions into smaller volume followed by recovery or secure disposal. For this purpose, many processes are being utilized such as precipitation, ion-exchange, solvent extraction and adsorption on solids etc. Interest in the adsorption of metal ions for recovery purposes has increased manyfold in recent years, because of its simplicity, selectivity and efficiency . The main advantage of adsorption is the separation of trace amount of elements from large volumes of solutions. In recent years, several studies have been made to recover radionuclides by adsorption using natural and synthetic adsorbents. Adsorption on charcoal is one of the most efficient techniques used in water treatment processes for the removal of organics and micropollutants from wastes and drinking waters. Adsorption processes have long been used in the removal of color, odor, and organic pollution. These processes are usually based on the use of activated carbon . Activated carbon consists mainly of carbon and is produced from every carbonaceous material. Activated carbon characterized by its high surface area and its wide distribution of porosity. The textural properties (surface area and porosity) of activated carbons play an important role in determining the capacity of the material in adsorption from aqueous solution. Chemistry of the surface is also important . Generally, activated carbons are mainly microporous, but in addition to micropores they contain meso- and macropores, which are very important in facilitating acces of the adsorbate molecules to the interior of carbon particles

  20. Adsorption of Rhodamine B on activated carbon obtained from pericarp of rubber fruit in comparison with the commercial activated carbon

    Directory of Open Access Journals (Sweden)

    Fareeda Hayeeye

    2014-04-01

    Full Text Available Adsorption of the dye, Rhodamine B, on activated carbon obtained from pericarp of rubber fruit (PrAC was investigated in comparison with the commercial activated carbon (CAC. Both activated carbons were characterized by scanning electron microscopy (SEM, specific surface area, and pH at point of zero charge (pHpzc. The effects of various experimental parameters such as contact time, dye concentration, amount of activated carbon, pH and temperature were analysed. The adsorption isotherm fitted well into the Langmuir model. By keeping pH constant at 4.0 and varying temperatures at 30, 40, 50, and 60°C, the maximum adsorption were 0.2306, 0.2356, 0.2756, and 0.2981 mmol g-1 for PrAC and 0.8957, 0.9588, 0.9841, and 1.0263 mmol g-1 for CAC, respectively. Study of the effect of temperature dependence of these adsorptions indicated that they were endothermic processes. The adsorption efficiency of Rhodamine B on PrAC is about 80-90%.

  1. First-principles study of H, O, and N adsorption on metal embedded carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Detian [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Luo, Haijun, E-mail: luohaijun@wzu.edu.cn [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Cai, Jianqiu [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Cheng, Yongjun [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Shao, Xiji [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Dong, Changkun, E-mail: dck@wzu.edu.cn [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China)

    2017-05-01

    Highlights: • Ni or Fe embedment and high atomic adsorption coverage benefit applications like hydrogen storage and field emission. • Ni or Fe embedment could help tune the catalytic properties. • Ni or Fe embedment enhances the adatom-SWNT interaction significantly. - Abstract: The density functional theory calculation has been conducted to investigate the structural and electronic properties, including the adsorption energies, bond structures, work functions, charge transfer behaviors, and density of states for pristine, Ni-, and Fe-embedded capped (5, 5) single-walled carbon nanotubes (SWNTs) with different coverage of atomic hydrogen, oxygen, and nitrogen adsorptions. Ni or Fe embedment enhances the adatom-SWNT interactions significantly for three kinds of gas atoms with the increases of the adsorption energies. The SWNT work function drops with H adsorption, while Ni or Fe embedment assists further the reduction. When increasing the coverage, the adsorption energy decreases and the work function climbs for O adsorption, but the nitrogen adsorption energy increases. The Bader charge transfer analysis implies that the cap possesses higher oxygen reduction activities than the tube, and the density of states analysis shows that Ni or Fe embedment deepens the C-adatom hybridizations.

  2. First-principles study of H, O, and N adsorption on metal embedded carbon nanotubes

    International Nuclear Information System (INIS)

    Li, Detian; Luo, Haijun; Cai, Jianqiu; Cheng, Yongjun; Shao, Xiji; Dong, Changkun

    2017-01-01

    Highlights: • Ni or Fe embedment and high atomic adsorption coverage benefit applications like hydrogen storage and field emission. • Ni or Fe embedment could help tune the catalytic properties. • Ni or Fe embedment enhances the adatom-SWNT interaction significantly. - Abstract: The density functional theory calculation has been conducted to investigate the structural and electronic properties, including the adsorption energies, bond structures, work functions, charge transfer behaviors, and density of states for pristine, Ni-, and Fe-embedded capped (5, 5) single-walled carbon nanotubes (SWNTs) with different coverage of atomic hydrogen, oxygen, and nitrogen adsorptions. Ni or Fe embedment enhances the adatom-SWNT interactions significantly for three kinds of gas atoms with the increases of the adsorption energies. The SWNT work function drops with H adsorption, while Ni or Fe embedment assists further the reduction. When increasing the coverage, the adsorption energy decreases and the work function climbs for O adsorption, but the nitrogen adsorption energy increases. The Bader charge transfer analysis implies that the cap possesses higher oxygen reduction activities than the tube, and the density of states analysis shows that Ni or Fe embedment deepens the C-adatom hybridizations.

  3. Pre-Combustion Carbon Dioxide Capture by a New Dual Phase Ceramic-Carbonate Membrane Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jerry Y. S. [Arizona State Univ., Tempe, AZ (United States)

    2015-01-31

    This report documents synthesis, characterization and carbon dioxide permeation and separation properties of a new group of ceramic-carbonate dual-phase membranes and results of a laboratory study on their application for water gas shift reaction with carbon dioxide separation. A series of ceramic-carbonate dual phase membranes with various oxygen ionic or mixed ionic and electronic conducting metal oxide materials in disk, tube, symmetric, and asymmetric geometric configurations was developed. These membranes, with the thickness of 10 μm to 1.5 mm, show CO2 permeance in the range of 0.5-5×10-7 mol·m-2·s-1·Pa-1 in 500-900°C and measured CO2/N2 selectivity of up to 3000. CO2 permeation mechanism and factors that affect CO2 permeation through the dual-phase membranes have been identified. A reliable CO2 permeation model was developed. A robust method was established for the optimization of the microstructures of ceramic-carbonate membranes. The ceramic-carbonate membranes exhibit high stability for high temperature CO2 separations and water gas shift reaction. Water gas shift reaction in the dual-phase membrane reactors was studied by both modeling and experiments. It is found that high temperature syngas water gas shift reaction in tubular ceramic-carbonate dual phase membrane reactor is feasible even without catalyst. The membrane reactor exhibits good CO2 permeation flux, high thermal and chemical stability and high thermal shock resistance. Reaction and separation conditions in the membrane reactor to produce hydrogen of 93% purity and CO2 stream of >95% purity, with 90% CO2 capture have been identified. Integration of the ceramic-carbonate dual-phase membrane reactor with IGCC process for carbon dioxide capture was analyzed. A methodology was developed to identify optimum operation conditions for a

  4. Carbon monoxide and methane adsorption of crude oil refinery using activated carbon from palm shells as biosorbent

    Science.gov (United States)

    Yuliusman; Afdhol, M. K.; Sanal, Alristo

    2018-03-01

    Carbon monoxide and methane gas are widely present in oil refineries. Off-potential gas is used as raw material for the petrochemical industry. In order for this off-gas to be utilized, carbon monoxide and methane must be removed from off-gas. This study aims to adsorb carbon monoxide and methane using activated carbon of palm shells and commercial activated carbon simultaneously. This research was conducted in 2 stages: 1) Preparation and characterization of activated carbon, 2) Carbon monoxide and methane adsorption test. The activation experiments using carbon dioxide at a flow rate of 150 ml/min yielded a surface area of 978.29 m2/g, Nitrogen at flow rate 150 ml/min yielded surface area 1241.48 m2/g, and carbon dioxide and nitrogen at a flow rate 200 ml/min yielded a surface area 300.37 m2/g. Adsorption of carbon monoxide and methane on activated carbon of palm shell systems yielded results in the amount of 0.5485 mg/g and 0.0649 mg/g and using commercial activated carbon yielded results in the amount of 0.5480 mg/g and 0.0650 mg/g

  5. Do Membranes Dream of Electric Tubes? Advanced Membranes Using Carbon Nanotube - Polymer Nanocomposites

    Science.gov (United States)

    de Lannoy, Charles-Francois Pedro Claude Karolek Ghislain

    Membrane technologies represent an energy efficient, effective solution for treating municipal and commercial waters/wastewaters. Membranes are predominantly polymer-based and despite steady advances in polymeric materials, they continue to suffer from operational problems including biofouling and breakages. This work addresses these two disparate problems by developing novel CNT-polymer nanocomposite materials that contain variously functionalized carbon nanotubes (fCNTs) in low quantities (phase and linked through ionic associations in polymer matrices showed significant (50%) increases in Young's modulus for certain CNT functionalizations and derivatization percent. Membranes formed with high surface electrical conductivity demonstrated almost complete resistance to biofouling (> 95%) in long-term bacterially challenged experiments. CNTs and polymer mixtures that lacked covalent or ionic bonds were susceptible to significant (up to 10%) loss of CNTs during membrane non-solvent gelation and aggressive chemical cleaning treatment. Functionalized carbon nanotubes endow polymer membranes with their unique strength and electrically conductive properties. These added properties were demonstrated to greatly improve membrane operational efficiency and membrane longevity. CNT-polymer nanocomposite membranes offer low-energy, high-efficiency, and long-lifetime alternatives to traditional polymer membranes. With further advances in polymeric nanomaterials, membrane technology has the potential for wide applicability across many fields outside of water filtration and desalination.

  6. Competitive adsorption of phenolic compounds from aqueous solution using sludge-based activated carbon.

    Science.gov (United States)

    Mohamed, E F; Andriantsiferana, C; Wilhelm, A M; Delmas, H

    2011-01-01

    Preparation of activated carbon from sewage sludge is a promising approach to produce cheap and efficient adsorbent for pollutants removal as well as to dispose of sewage sludge. The first objective of this study was to investigate the physical and chemical properties (BET surface area, ash and elemental content, surface functional groups by Boehm titration and weight loss by thermogravimetric analysis) of the sludge-based activated carbon (SBAC) so as to give a basic understanding of its structure and to compare to those of two commercial activated carbons, PICA S23 and F22. The second and main objective was to evaluate the performance of SBAC for single and competitive adsorption of four substituted phenols (p-nitrophenol, p-chlorophenol, p-hydroxy benzoic acid and phenol) from their aqueous solutions. The results indicated that, despite moderate micropore and mesopore surface areas, SBAC had remarkable adsorption capacity for phenols, though less than PICA carbons. Uptake of the phenolic compound was found to be dependent on both the porosity and surface chemistry of the carbons. Furthermore, the electronegativity and the hydrophobicity of the adsorbate have significant influence on the adsorption capacity. The Langmuir and Freundlich models were used for the mathematical description of the adsorption equilibrium for single-solute isotherms. Moreover, the Langmuir-Freundlich model gave satisfactory results for describing multicomponent system isotherms. The capacity of the studied activated carbons to adsorb phenols from a multi-solute system was in the following order: p-nitrophenol > p-chlorophenol > PHBA > phenol.

  7. Synthesis carbon foams prepared from gelatin (CFG) for cadmium ion adsorption

    Science.gov (United States)

    Ulfa, M.; Ulfa, D. K.

    2018-01-01

    In this paper, carbon foam from gelatin (CFG) was synthesized by acid-catalyzed carbonization of gelatin solution on mild condition by the simple method. Gelatin (Ge) were used as sacrificial template and source of carbon. Sulphuric acid was used as acid catalyst. Carbon foam CFG sample were characterized by scanning electron microscope (SEM), nitrogen adsorption desorption and FTIR for knowing textural and structural properties of the sample. Carbon foam CFG sample demonstrated macro pipes-channel like with pore size that varies between 30-40 μ and surface area m 60-100 m2g-1. The carbon foams CFG sample were tested by using adsorption process for obtained their performance for decreasing Cd(II) ions from aqueous solutions. The adsorption capacities for cadmium was 46.7 mg/g obtained by using adsorbent dose 50 mg, initial concentration 50 ppm, contact time, 3 h; room temperature, stirring rate 150 rpm) which reached equilibrium at 55 min. Adsorption process fits using using Lagergren and Ho and McKay equation and measuring data

  8. Ligand adsorption on an activated carbon for the removal of chromate ions from aqueous solutions.

    Science.gov (United States)

    García-Martín, J; López-Garzón, R; Godino-Salido, M Luz; Gutiérrez-Valero, M Dolores; Arranz-Mascarós, P; Cuesta, R; Carrasco-Marín, F

    2005-07-19

    The results presented in this work are related to the design of a guideline to develop specific properties at the surface of an activated carbon (AC). For this, two model aromatic compounds have been synthesized and their electrolytic behavior in aqueous solutions was studied by a potentiometric method. The textural characteristics of the activated carbon were determined by porosimetry methods. The nature of oxygen-carrying functions and the acid-base behavior of the AC surface were characterized by TPD and potentiometric titration methods, respectively. The adsorption and desorption equilibria of the aromatic compounds on activated carbon were measured in aqueous solutions, and the hysteresis between adsorption and desorption, which reveals irreversible adsorption, was discussed on the basis of the frontier orbital theory. HOMO and LUMO orbitals of the adsorbent and adsorbates were calculated, and irreversible adsorption was attributed to the small energy difference between HOMO and LUMO of the aromatic adsorbates and the adsorbent. Adsorption equilibria of K2CrO4 in aqueous solution on the AC alone and on the AC-aromatic ligand adsorbents, respectively, prove the efficient development of specific chemical functions at the carbon surface provided by the adsorbed aromatic compounds.

  9. Adsorption of mercury (II from liquid solutions using modified activated carbons

    Directory of Open Access Journals (Sweden)

    Hugo Soé Silva

    2010-06-01

    Full Text Available Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury abatement. Activated carbons are universal adsorbents which have been found to be a very effective alternative for mercury removal from water. The effectiveness with which a contaminant is adsorbed by the solid surface depends, among other factors, on the charge of the chemical species in which the contaminant is in solution and on the net charge of the adsorbent surface which depend on the pH of the adsorption system. In this work, activated carbon from carbonized eucalyptus wood was used as adsorbent. Two sulphurization treatments by impregnation with sulphuric acid and with carbon disulphide, have been carried out to improve the adsorption capacity for mercury entrapment. Batch adsorption tests at different temperatures and pH of the solution were carried out. The influence of the textural properties, surface chemistry and operation conditions on the adsorption capacity, is discussed.

  10. Tuning the Pore Geometry of Ordered Mesoporous Carbons for Enhanced Adsorption of Bisphenol-A

    Science.gov (United States)

    Libbrecht, Wannes; Vandaele, Koen; De Buysser, Klaartje; Verberckmoes, An; Thybaut, Joris W.; Poelman, Hilde; De Clercq, Jeriffa; Van Der Voort, Pascal

    2015-01-01

    Mesoporous carbons were synthesized via both soft and hard template methods and compared to a commercial powder activated carbon (PAC) for the adsorption ability of bisphenol-A (BPA) from an aqueous solution. The commercial PAC had a BET-surface of 1027 m2/g with fine pores of 3 nm and less. The hard templated carbon (CMK-3) material had an even higher BET-surface of 1420 m2/g with an average pore size of 4 nm. The soft templated carbon (SMC) reached a BET-surface of 476 m2/g and a pore size of 7 nm. The maximum observed adsorption capacity (qmax) of CMK-3 was the highest with 474 mg/g, compared to 290 mg/g for PAC and 154 mg/g for SMC. The difference in adsorption capacities was attributed to the specific surface area and hydrophobicity of the adsorbent. The microporous PAC showed the slowest adsorption, while the ordered mesopores of SMC and CMK-3 enhanced the BPA diffusion into the adsorbent. This difference in adsorption kinetics is caused by the increase in pore diameter. However, CMK-3 with an open geometry consisting of interlinked nanorods allows for even faster intraparticle diffusion. PMID:28788023

  11. Destructive Adsorption of Carbon Tetrachloride on Alkaline Earth Metal Oxides

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Mestl, Gerhard; Rosynek, Michael P.; Krawietz, Thomas R.; Haw, James F.; Lunsford, Jack H.

    1998-01-01

    The destructive adsorption of CCl4 on MgO, CaO, SrO, and BaO has been studied as a function of the reaction temperature and the amount of CCl4 injected. The reaction was followed using in situ Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and 13 C

  12. Mathematical Modelling of Nitrate Removal from Water Using a Submerged Membrane Adsorption Hybrid System with Four Adsorbents

    Directory of Open Access Journals (Sweden)

    Mahatheva Kalaruban

    2018-01-01

    Full Text Available Excessive concentrations of nitrate in ground water are known to cause human health hazards. A submerged membrane adsorption hybrid system that includes a microfilter membrane and four different adsorbents (Dowex 21K XLT ion exchange resin (Dowex, Fe-coated Dowex, amine-grafted (AG corn cob and AG coconut copra operated at four different fluxes was used to continuously remove nitrate. The experimental data obtained in this study was simulated mathematically with a homogeneous surface diffusion model that incorporated membrane packing density and membrane correlation coefficient, and applied the concept of continuous flow stirred tank reactor. The model fit with experimental data was good. The surface diffusion coefficient was constant for all adsorbents and for all fluxes. The mass transfer coefficient increased with flux for all adsorbents and generally increased with the adsorption capacity of the adsorbents.

  13. Kinetics and thermodynamics of human serum albumin adsorption on silicon doped diamond like carbon

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Mukhtar H., E-mail: ahmed-m@email.ulster.ac.uk; Byrne, John A.; McLaughlin, James

    2015-03-15

    To gain a better understanding of protein adsorption onto biomaterial surfaces is required for the control of biocompatibility and bioactivity. Various samples of diamond like carbon (DLC) and silicon-doped DLC were synthesised using plasma enhanced chemical vapour deposition (PECVD). The effects of surface morphology on the interaction of human serum albumin (HSA) with doped and undoped DLC films was investigated using spectroscopic ellipsometry (SE) and other surface analysis techniques. The results highlighted an increase in both contact angle and hydrophobicity with increasing silicon dopant levels. A reduction on the contact angle values. After adsorption of HSA, the films showed a reduction in the contact angle with a significant change in the cosΔ and this gap increased with increasing surface coverage of HSA. The adsorption kinetics of HSA were also investigated and revealed that the maximum adsorption occurred at pH 5.0 and the process involved chemisorption. The experimental isotherm data were analysed using the Langmuir and Freundlich‎ models. The amount of HSA adsorbed increased with contact time and reached saturation ‎after 30 min. The adsorption ‎process was found to be pseudo first order with respect to the bulk concentration and was dependent on both the concentration of protein and surface characteristics of the samples. The amount of adsorbed HSA was higher with higher levels of silicon doping of the DLC. Therefore, doping DLC may provide an approach to controlling the protein adsorption. - Graphical abstract: The average thickness layer of HSA measurement onto surfaces of DLC and Si-DLC. - Highlights: • Diamond Like Carbon (DLC) and Silicon doped DLC were synthesised and characterised. • Si-DLC increases the hydrophobicity and decreases the surface free energy. • Adsorption study using human serum albumin (HSA). • The adsorbed amount of HSA increases with increasing of Silicon content DLC. • Adsorption process follow pseudo

  14. Study of carbon dioxide adsorption on a Cu-nitroprusside polymorph

    International Nuclear Information System (INIS)

    Roque-Malherbe, R.; Lozano, C.; Polanco, R.; Marquez, F.; Lugo, F.; Hernandez-Maldonado, A.; Primera-Pedrozo, J.N.

    2011-01-01

    A careful structural characterization was carried out to unequivocally determine the structure of the synthesized material. The TGA, DRIFTS and a Pawley fitting of the XRD powder profiles indicate that the hydrated and in situ dehydrated polymorph crystallizes in the orthorhombic space group Pnma. Meanwhile, the CO 2 isosteric heat of adsorption appears to be independent of loading with an average value of 30 kJ/mol. This translates to a physisorption type interaction, where the adsorption energy corresponding to wall and lateral interactions are mutually compensated to produce, an apparently, homogeneous adsorption energy. The somewhat high adsorption energy is probably due to the confinement of the CO 2 molecules in the nitroprusside pores. Statistical Physics and the Dubinin theory for pore volume filling allowed model the CO 2 equilibrium adsorption process in Cu-nitroprusside. A DRIFTS test for the adsorbed CO 2 displayed a peak at about 2338 cm -1 that was assigned to a contribution due to physical adsorption of the molecule. Another peak found at 2362 cm -1 evidenced that this molecule interacts with the Cu 2+ , which appears to act as an electron accepting Lewis acid site. The aim of the present paper is to report a Pnma stable Cu-nitroprusside polymorph obtained by the precipitation method that can adsorb carbon dioxide. -- Graphical abstract: The adsorption space of a very well characterized Cu-nitroprusside polymorph, applying carbon dioxide as probe molecule, was studied. Display Omitted Highlights: → Accurate information about the geometry of the adsorption space was provided. → Truthful data about the interactions within the adsorption space was presented. → The structure of the tested Cu-NP polymorph was established. → Was evidenced adsorbed CO 2 molecules in the form of weakly bonded adducts. → Is proposed that adsorbed molecules could change the Cu-NP magnetic properties.

  15. AUSTRALIAN PINE CONES-BASED ACTIVATED CARBON FOR ADSORPTION OF COPPER IN AQUEOUS SOLUTION

    Directory of Open Access Journals (Sweden)

    MUSLIM A.

    2017-02-01

    Full Text Available The Australian Pine cones (APCs was utilised as adsorbent material by physical and chemical activation for the adsorption Cu(II in aqueous solution. FTIR and SEM analysis were conducted to obtain the active site and to characterise the surface morphology of the APCs activated carbon (APCs AC prepared through pyrolysis at 1073.15 K and alkaline activation of NaOH. The independent variables effect such as contact time, Cu(II initial concentration and the activator ratio in the ranges of 0-150 min, 84.88-370.21 mg/l and 0.2-0.6 (NaOH:APCs AC, respectively on the Cu(II adsorption capacity were investigated in the APCs activated carbon-solution (APCs ACS system with 1 g the APCs AC in 100 mL Cu(II aqueous solution with magnetic stirring at 75 rpm, room temperature of 298.15 K (± 2 K, 1 atm and pH 5 (±0.25. As the results, Cu(II adsorption capacity dramatically increased with increasing contact time and Cu(II initial concentration. The optimal Cu(II adsorption capacity of 26.71 mg/g was obtained in the APCs ACS system with 120-min contact time, 340.81 m/l initial Cu(II and 0.6 activator ratio. The kinetics study showed the Cu(II adsorption kinetics followed the pseudo-second-order kinetics with 27.03 mg/g of adsorption capacity, 0.09 g/mg.min of rate constant and 0.985-R2. In addition, the Cu(II adsorption isotherm followed the Langmuir model with 12.82 mg/g of the mono-layer adsorption capacity, 42.93 l/g of the over-all adsorption capacity and 0.954-R2.

  16. Impact of operation conditions, foulant adsorption, and chemical cleaning on the nanomechanical properties of ultrafiltraion hollow fiber membranes

    KAUST Repository

    Gutierrez, Leonardo

    2018-04-06

    This study analyzed the change in nanomechanical properties of ultrafiltration hollow fiber membranes harvested from pilot-scale units after twelve months of operation. Quantitative Nanomechanical Mapping technique was used to distinguish between adhesion, dissipation, deformation, and modulus while simultaneously generating a topographic image of membranes. Nanomechanical maps of virgin membranes evidenced surfaces of heterogeneous properties and were described by probability density functions. Operating conditions and feed quality exerted an impact on membranes. Clean harvested membranes showed a higher mean modulus and dissipation, and a lower deformation than virgin membranes, indicating stiffer membranes of lower elastic deformation. A significant fraction of these measurements displayed peak values deviating from the distribution; which represents regions of the membrane with properties highly differing from the probability density function. The membrane polymeric material experienced severe physicochemical changes by foulant adsorption and reaction with cleaning agents. Foulant adsorption on membranes was heterogeneous in both morphology and mechanical properties and could not be statistically described. Foulants, i.e., mainly consisting of polysaccharides and proteinaceous structures, displayed low elastic deformation and high roughness and adhesion. The presence of foulants after chemical cleaning and their high adhesion would be a direct nanoscale evidence of irreversible fouling. By the end of the operation, the Trans-Membrane Pressure experienced a 40% increase. The cleaning process was not able to fully recover the initial TMP, indicating irreversible fouling, i.e., permanent change in membrane characteristics and decrease in performance. These results suggest a link between the macroscopic properties and nanomechanical characteristics of membranes. This study advances our nanoscale understanding of the impact of fouling and operating conditions on

  17. Adsorption Isotherms of CH 4 on Activated Carbon from Indonesian Low Grade Coal

    KAUST Repository

    Martin, Awaludin

    2011-03-10

    This article presents an experimental approach for the determination of the adsorption isotherms of methane on activated carbon that is essential for methane storage purposes. The experiments incorporated a constant-volume- variable-pressure (CVVP) apparatus, and two types of activated carbon have been investigated, namely, activated carbon derived from the low rank coal of the East of Kalimantan, Indonesia, and a Carbotech activated carbon. The isotherm results which cover temperatures from (300 to 318) K and pressures up to 3.5 MPa are analyzed using the Langmuir, Tóth, and Dubinin-Astakhov (D-A) isotherm models. The heat of adsorption for the single component methane-activated carbon system, which is concentration- and temperature-dependent, is determined from the measured isotherm data. © 2011 American Chemical Society.

  18. Removal and Adsorption of p-Nitrophenol from Aqueous Solutions Using Carbon Nanotubes and Their Composites

    Directory of Open Access Journals (Sweden)

    Yuan-Xiang Yao

    2014-01-01

    Full Text Available In an attempt to explore the possibility of using carbon nanotubes (CNTs as efficient adsorbents for removal of pollutants from the contaminated water, the adsorption of p-nitrophenol (PNP on raw multiwalled carbon nanotubes (r.MWNTs with different outer diameters, various functionalized multiwalled carbon nanotubes (f-MWNTs, raw single-walled carbon nanotubes (r.SWNTs and oxidized single-walled carbon nanotubes (ox-SWNTs has been investigated. The ox-SWNTs showed better adsorption ability for PNP with different concentrations, while lower uptake capacity was found for all of the r.MWNTs and f-MWNTs. The removal efficiency of PNP by ox-SWNTs was around 98%, indicating that ox-SWNTs possess a great potential application prospect for removing PNP from aqueous solutions.

  19. Comparative study of the adsorption of acetaminophen on activated carbons in simulated gastric fluid

    OpenAIRE

    Rey-Mafull, Carlos A; Tacoronte, Juan E; Garcia, Raquel; Tobella, Jorge; Llópiz, Julio C; Iglesias, Alberto; Hotza, Dachamir

    2014-01-01

    Samples of commercial activated carbons (AC) obtained from different sources: Norit E Supra USP, Norit B Test EUR, and ML (Baracoa, Cuba) were investigated. The adsorption of acetaminophen, Co = 2500 mg/L, occured in simulated gastric fluid (SGF) at pH 1.2 in contact with activated carbon for 4 h at 310 K in water bath with stirring. Residual acetaminophen was monitored by UV visible. The results were converted to scale adsorption isotherms using alternative models: Langmuir TI and TII, Freun...

  20. Phenol Adsorption on Nitrogen-enriched Activated Carbon Prepared from Bamboo Residues

    OpenAIRE

    Ji Zhang; Xiao-Juan Jin; Jian-Min Gao; Xiu-Dong Zhang

    2013-01-01

    Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, t...

  1. Hyperbranched-polyol-tethered poly (amic acid) electrospun nanofiber membrane with ultrahigh adsorption capacity for boron removal

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhe; Wu, Zhongyu; Zhang, Yufeng; Meng, Jianqiang, E-mail: jianqiang.meng@hotmail.com

    2017-04-30

    Highlights: • Electrospun nanofiber membranes were grafted with hyperbranched polyols. • The membrane had a maximum boron uptake of 5.68 mmol/g. • The membrane could adsorb 0.82 mmol/g boron from a 5 mg/L solution in 15 min. • The membrane obeyed the Langmuir and the pseudo-first-order kinetic model. • The regeneration efficiency remained over 90% after 10 cycled uses. - Abstract: The development of efficient adsorbents with high sorption capacity remains as a challenge for the removal of micropollutants occurred globally in water resources. In this work, poly (amic acid) (PAA) electrospun nanofiber membranes grafted with hyperbranched polyols were synthesized and used for boron removal. The PAA nanofiber was reacted with hyperbranched polyethylenimine (HPEI) and further with glycidol to introduce the vicinal hydroxyl groups. The chemical composition and surface characteristics of the obtained PAA-g-PG membranes were evaluated by FESEM, FTIR, XPS and water contact angles (WCA) measurements. The boron adsorption thermodynamics and kinetics were investigated systematically. The results showed that the PAA nanofiber spun from concentration of 15% had uniform morphology and narrow diameter distribution. The PAA-g-PG nanofiber membrane had a maximum boron uptake of 5.68 mmol/g and could adsorb 0.82 mmol/g boron from a 5 mg/L solution in 15 min. Both the high surface area of nanofibers and the hyperbranched structure should contribute to the high boron uptake and high adsorption rate. The nanofiber membrane obeyed the Langmuir adsorption model and the pseudo-first-order kinetic model. The regeneration efficiency of the nanofiber membrane remained 93.9% after 10 cycled uses, indicating good regenerability of the membrane.

  2. Hyperbranched-polyol-tethered poly (amic acid) electrospun nanofiber membrane with ultrahigh adsorption capacity for boron removal

    Science.gov (United States)

    Wang, Zhe; Wu, Zhongyu; Zhang, Yufeng; Meng, Jianqiang

    2017-04-01

    The development of efficient adsorbents with high sorption capacity remains as a challenge for the removal of micropollutants occurred globally in water resources. In this work, poly (amic acid) (PAA) electrospun nanofiber membranes grafted with hyperbranched polyols were synthesized and used for boron removal. The PAA nanofiber was reacted with hyperbranched polyethylenimine (HPEI) and further with glycidol to introduce the vicinal hydroxyl groups. The chemical composition and surface characteristics of the obtained PAA-g-PG membranes were evaluated by FESEM, FTIR, XPS and water contact angles (WCA) measurements. The boron adsorption thermodynamics and kinetics were investigated systematically. The results showed that the PAA nanofiber spun from concentration of 15% had uniform morphology and narrow diameter distribution. The PAA-g-PG nanofiber membrane had a maximum boron uptake of 5.68 mmol/g and could adsorb 0.82 mmol/g boron from a 5 mg/L solution in 15 min. Both the high surface area of nanofibers and the hyperbranched structure should contribute to the high boron uptake and high adsorption rate. The nanofiber membrane obeyed the Langmuir adsorption model and the pseudo-first-order kinetic model. The regeneration efficiency of the nanofiber membrane remained 93.9% after 10 cycled uses, indicating good regenerability of the membrane.

  3. Volatile organic carbon/air separation test using gas membranes

    International Nuclear Information System (INIS)

    King, C.V.; Kaschemekat, J.

    1993-08-01

    An estimated 900 metric tons of carbon tetrachloride were discharged to soil columns during the Plutonium Finishing Plant Operations at the Hanford Site. The largest percentage of this volatile organic compound was found in the vadose region of the 200 West Area. Using a Vacuum Extraction System, the volatile organic compound was drawn from the soil in an air mixture at a concentration of about 1,000 parts per million. The volatile organic compounds were absorbed from the air stream using granulated activated carbon canisters. A gas membrane separation system, developed by Membrane Technology and Research, Inc., was tested at the Vacuum Extraction System site to determine if the volatile organic compound load on the granulated activated carbon could be reduced. The Vacuum Extraction System condensed most of the volatile organic compound into liquid carbon tetrachloride and vented the residual gas stream into the granulated activated carbon. This system reduced the cost of operation about $5/kilogram of volatile organic compound removed

  4. Adsorption kinetics of NO on ordered mesoporous carbon (OMC) and cerium-containing OMC (Ce-OMC)

    Science.gov (United States)

    Chen, Jinghuan; Cao, Feifei; Chen, Songze; Ni, Mingjiang; Gao, Xiang; Cen, Kefa

    2014-10-01

    Ordered mesoporous carbon (OMC) and cerium-containing OMC (Ce-OMC) were prepared using evaporation-induced self-assembly (EISA) method and used to adsorb NO. N2 sorption, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm their structures. The results showed that the ordered and uniform structures were successfully synthesized and with the introduction of cerium pore properties were not significantly changed. The NO adsorption capacity of OMC was two times larger than that of activated carbon (AC). With the introduction of cerium both the adsorption capacity and the adsorption rate were improved. The effects of residence time and oxygen concentration on NO adsorption were also investigated. Oxygen played an important role in the NO adsorption (especially in the form of chemisorption) and residence time had small influence on the NO adsorption capacity. The NO adsorption kinetics was analyzed using pseudo-first-order, pseudo-second-order, Elovich equation and intraparticle diffusion models. The results indicated that the NO adsorption process can be divided into rapid adsorption period, slow adsorption period, and equilibrium adsorption period. The pseudo-second-order model was the most suitable model for NO adsorption on OMC and Ce-OMC. The rate controlling step was the intraparticle diffusion together with the adsorption reaction.

  5. Modeling and Optimization for Production of Rice Husk Activated Carbon and Adsorption of Phenol

    Directory of Open Access Journals (Sweden)

    Y. S. Mohammad

    2014-01-01

    Full Text Available Modeling of adsorption process establishes mathematical relationship between the interacting process variables and process optimization is important in determining the values of factors for which the response is at maximum. In this paper, response surface methodology was employed for the modeling and optimization of adsorption of phenol onto rice husk activated carbon. Among the action variables considered are activated carbon pretreatment temperature, adsorbent dosage, and initial concentration of phenol, while the response variables are removal efficiency and adsorption capacity. Regression analysis was used to analyze the models developed. The outcome of this research showed that 99.79% and 99.81% of the variations in removal efficiency and adsorption capacity, respectively, are attributed to the three process variables considered, that is, pretreatment temperature, adsorbent dosage, and initial phenol concentration. Therefore, the models can be used to predict the interaction of the process variables. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at initial solute concentration of 40.61 mg/L, pretreatment temperature of 441.46°C, adsorbent dosage 4 g, adsorption capacity of 0.9595 mg/g, and removal efficiency of 97.16%. These optimum operating conditions were experimentally validated.

  6. Equilibrium, kinetic and thermodynamic studies for adsorption of BTEX onto Ordered Mesoporous Carbon (OMC).

    Science.gov (United States)

    Konggidinata, Mas Iwan; Chao, Bing; Lian, Qiyu; Subramaniam, Ramalingam; Zappi, Mark; Gang, Daniel Dianchen

    2017-08-15

    Chemical and petrochemical industries produce substantial amounts of wastewater everyday. This wastewater contains organic pollutants such as benzene, toluene, ethylbenzene and xylenes (BTEX) that are toxic to human and aquatic life. Ordered Mesoporous Carbon (OMC), the adsorbent that possesses the characteristics of an ideal adsorbent was investigated to understand its properties and suitability for BTEX removal. Adsorption isotherms, adsorption kinetics, the effects of initial BTEX concentrations and temperatures on the adsorption process were studied. The OMCs were characterized using surface area and pore size analyzer, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR). The results suggested that the Langmuir Isotherm and Pseudo-Second-Order Models described the experimental data well. The thermodynamic parameters, Gibbs free energy (ΔG°), the enthalpy change (ΔH°) and the entropy change (ΔS°) of adsorption indicated that the adsorption processes were physical, endothermic, and spontaneous. In addition, OMC had 27% higher overall adsorption capacities compared to granular activated carbon (GAC). Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Adsorption of hydrogen in Scandium/Titanium decorated nitrogen doped carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Mananghaya, Michael, E-mail: mikemananghaya@gmail.com [De La Salle University, 2401 Taft Ave, 0922, Manila (Philippines); DLSU STC Laguna Boulevard, LTI Spine Road Barangays Biñan and Malamig, Biñan City, Laguna (Philippines); DOST-ASTHRDP, PCIEERD, Gen. Santos Ave., Bicutan, Taguig City 1631 (Philippines); Belo, Lawrence Phoa; Beltran, Arnel [De La Salle University, 2401 Taft Ave, 0922, Manila (Philippines); DLSU STC Laguna Boulevard, LTI Spine Road Barangays Biñan and Malamig, Biñan City, Laguna (Philippines)

    2016-09-01

    Nitrogen doped Carbon Nanotube with divacancy (4ND-CN{sub x}NT) that is decorated with Scandium and Titanium as potential hydrogen storage medium using the pseudo potential density functional method was investigated. Highly localized states near the Fermi level, which are derived from the nitrogen defects, contribute to strong Sc and Ti bindings, which prevent metal aggregation and improve the material stability. A detailed Comparison of the Hydrogen adsorption capability with promising system-weight efficiency of Sc over Ti was elucidated when functionalized with 4ND-CN{sub x}NT. Finally, the (Sc/4ND){sub 10}-CN{sub x}CNT composite material has a thermodynamically favorable adsorption and consecutive adsorption energy for ideal reversible adsorption and desorption of hydrogen at room temperature such that it can hold at least 5.8 wt% hydrogen molecules at the LDA and GGA level. - Highlights: • Carbon Nanotube with divacancy (4ND-CN{sub x}NT) decorated with Sc and Ti. • Nitrogen defects, contribute to strong Sc and Ti bindings. • H{sub 2} and (Sc/4ND){sub 10}-CN{sub x}CNT has a favorable adsorption. • 5.8 wt% adsorption at the LDA and GGA level.

  8. An experimental design approach for modeling As(V) adsorption from aqueous solution by activated carbon.

    Science.gov (United States)

    Bakkal Gula, C; Bilgin Simsek, E; Duranoglu, D; Beker, U

    2015-01-01

    The present paper discusses response surface methodology as an efficient approach for predictive model building and optimization of As(V) adsorption on activated carbon derived from a food industry waste: peach stones. The objectives of the study are application of a three-factor 2³ full factorial and central composite design technique for maximizing As(V) removal by produced activated carbon, and examination of the interactive effects of three independent variables (i.e., solution pH, temperature, and initial concentration) on As(V) adsorption capacity. Adsorption equilibrium was investigated by using Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. First-order and second-order kinetic equations were used for modeling of adsorption kinetics. Thermodynamic parameters (ΔG °, ΔH °, and ΔS °) were calculated and used to explain the As(V) adsorption mechanism. The negative value of ΔH (-7.778 kJ mol⁻¹) supported the exothermic nature of the sorption process and the Gibbs free energy values (ΔG°) were found to be negative, which indicates that the As(V) adsorption is feasible and spontaneous.

  9. Kinetics of Adsorption of Ferrous Ion onto Acid Activated Carbon from Zea Mays Dust

    Directory of Open Access Journals (Sweden)

    P. K. Baskaran

    2011-01-01

    Full Text Available The batch removal of ferrous ion from aqueous solution using low cost adsorbents such as zea mays dust carbon(ZDC under different experimental conditions were investigated in this study. The process parameters studied include agitation time, initial metal ion concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm obtained from the Langmuir isotherm plot were found to 37.17, 38.31, 39.37 and 40.48 mg/g. The temperature variation study showed that the ferrous ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the ferrous ion solutions. The Langmuir and Freundlich adsorption isotherms obtained positive ΔH0 value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of ferrous ion on ZDC involves physisorption mechanism.

  10. Effect of surface acidic oxides of activated carbon on adsorption of ammonia.

    Science.gov (United States)

    Huang, Chen-Chia; Li, Hong-Song; Chen, Chien-Hung

    2008-11-30

    The influence of surface acidity of activated carbon (AC) was experimentally studied on adsorption of ammonia (NH(3)). Coconut shell-based AC was modified by various acids at different concentrations. There were five different acids employed to modified AC, which included nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and acetic acid. Acidic functional groups on the surface of ACs were determined by a Fourier transform infrared spectrograph (FTIR) and by the Boehm titration method. Specific surface area and pore volume of the ACs were measured by a nitrogen adsorption apparatus. Adsorption amounts of NH(3) onto the ACs were measured by a dynamic adsorption system at room temperature according to the principle of the ASTM standard test method. The concentration of NH(3) in the effluent stream was monitored by a gas-detecting tube technique. Experimental results showed that adsorption amounts of NH(3) on the modified ACs were all enhanced. The ammonia adsorption amounts on various activated carbons modified by different acids are in the following order: nitric acid>sulfuric acid>acetic acid approximately phosphoric acid>hydrochloric acid. It is worth to note that the breakthrough capacity of NH(3) is linearly proportional to the amount of acidic functional groups of the ACs.

  11. Adsorption Equilibrium and Kinetics of the Removal of Ammoniacal Nitrogen by Zeolite X/Activated Carbon Composite Synthesized from Elutrilithe

    OpenAIRE

    Zhang, Yong; Yu, Feng; Cheng, Wenping; Wang, Jiancheng; Ma, Juanjuan

    2017-01-01

    Zeolite X/activated carbon composite material (X/AC) was prepared from elutrilithe, by a process consisting of carbonization, activation, and subsequent hydrothermal transformation of aluminosilicate in alkaline solution, which was used for the removal of ammoniacal nitrogen from aqueous solutions. Adsorption kinetics, equilibrium, and thermodynamic were studied and fitted by various models. The adsorption kinetics is best depicted by pseudosecond-order model, and the adsorption isotherm fits...

  12. Recovery of glycols, sugars, and Related Multiple -OH Compounds from Dilute-Aqueous Solution by Regenerable Adsorption onto Activated Carbons

    Energy Technology Data Exchange (ETDEWEB)

    Chinn, Daniel [Univ. of California, Berkeley, CA (United States)

    1999-06-01

    The present research explores the use of adsorption onto activated carbons as a means of recover glycerol, glycols, and sugars from dilute-aqueous solution. Our work is focused on understanding the mechanisms of adsorption onto carbons, assessing the degree of adsorption reversibility with precision, and implementing a bench-scale recovery process that results in a higher product concentration and reduction of the energy load for final purification.

  13. Membrane Systems Engineering for Post-combustion Carbon Capture

    KAUST Repository

    Alshehri, Ali

    2013-08-05

    This study proposes a strategy for optimal design of hollow fiber membrane networks for post combustion carbon capture from power plant multicomponent flue gas. A mathematical model describing multicomponent gas permeation through a separation membrane was customized into the flowsheet modeling package ASPEN PLUS. An N-stage membrane network superstructure was defined considering all possible flowsheeting configurations. An optimization formulation was then developed and solved using an objective function that minimizes the costs associated with operating and capital expenses. For a case study of flue gas feed flow rate of 298 m3/s with 13% CO2 and under defined economic parameters, the optimization resulted in the synthesis of a membrane network structure consisting of two stages in series. This optimal design was found while also considering feed and permeate pressures as well as recycle ratios between stages. The cost of carbon capture for this optimal membrane network is estimated to be $28 per tonne of CO2 captured, considering a membrane permeance of 1000 GPU and membrane selectivity of 50. Following this approach, a reduction in capture cost to less than $20 per tonne CO2 captured is possible if membranes with permeance of 2000 GPU and selectivity higher than 70 materialize.

  14. Effects of Surface Treatment of Activated Carbon on Its Surface and Cr(VI) Adsorption Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Jang, Yu Sin [Advanced Materials Division., Korea Research Institute of Chimical Technology, Taejon (Korea)

    2001-04-01

    In this work, the effect of surface treatments on activated carbons (ACs) has been studied in the context of gas and liquid adsorption behaviors. The chemical solutions used in this experiment were 35% sodium hydroxide, and these were used for the acidic and basic treatments, respectively. The surface properties have been determined by pH, acid-base values, and FT-IR. The adsorption isotherms of Cr(VI) ion on activated carbons have been studied with the 5 mg/l concentration at ambient temperature. N{sub 2} adsorption isotherm characteristics, which include the specific surface area, micro pore volume, and microporosity, were determined by BET and Boer's-plot methods. In case of the acidic treatment of activated carbons, it was observed that the adsorption of Cr(VI) ion was more effective due to the increase acid value (or acidic functional group) of activated carbon surfaces. However, the basic treatment on activated carbons was caused no significant effects, probably due to the decreased specific surface area and total pore volume. 27 refs., 7 figs., 4 tabs.

  15. Adsorption of Arsenate by Nano Scaled Activated Carbon Modified by Iron and Manganese Oxides

    Directory of Open Access Journals (Sweden)

    George P. Gallios

    2017-09-01

    Full Text Available The presence of arsenic in water supplies is a major problem for public health and still concerns large parts of population in Southeast Asia, Latin America and Europe. Removal of arsenic is usually accomplished either by coagulation with iron salts or by adsorption with iron oxides or activated alumina. However, these materials, although very efficient for arsenic, normally do not remove other undesirable constituents from waters, such as chlorine and organo-chlorine compounds, which are the results of water chlorination. Activated carbon has this affinity for organic compounds, but does not remove arsenic efficiently. Therefore, in the present study, iron modified activated carbons are investigated as alternative sorbents for the removal of arsenic(V from aqueous solutions. In addition, modified activated carbons with magnetic properties can easily be separated from the solutions. In the present study, a simple and efficient method was used for the preparation of magnetic Fe3(Mn2+O4 (M:Fe and/or Mn activated carbons. Activated carbons were impregnated with magnetic precursor solutions and then calcinated at 400 °C. The obtained carbons were characterized by X-ray diffraction (XRD, nitrogen adsorption isotherms, scanning electron microscopy (SEM, vibrating sample magnetometer (VSM, Fourier Transform Infrared Spectrometry (FTIR and X-ray photoelectron spectroscopy (XPS measurements. Their adsorption performance for As(V was evaluated. The iron impregnation presented an increase in As(V maximum adsorption capacity (Qmax from about 4 mg g−1 for the raw carbon to 11.05 mg g−1, while Mn incorporation further increased the adsorption capacity at 19.35 mg g−1.

  16. Nuclear quantum effect on hydrogen adsorption site of zeolite-templated carbon model using path integral molecular dynamics

    International Nuclear Information System (INIS)

    Suzuki, Kimichi; Kayanuma, Megumi; Tachikawa, Masanori; Ogawa, Hiroshi; Nishihara, Hirotomo; Kyotani, Takashi; Nagashima, Umpei

    2011-01-01

    Research highlights: → The stable hydrogen adsorption sites on C 36 H 12 were evaluated at 300 K using path integral molecular dynamics. → In the static MO calculation and conventional MD simulation, five stable adsorption sites of hydrogen atom were found. → In path integral simulation, only four stable adsorption sites were obtained. → The thermal and nuclear quantum effects are key role to settle the hydrogen adsorption sites on carbon materials. - Abstract: To settle the hydrogen adsorption sites on buckybowl C 36 H 12 , which is picked up from zeolite-templated carbon (ZTC), we have performed path integral molecular dynamics (PIMD) simulation including thermal and nuclear quantum fluctuations under semi-empirical PM3 method. In the static PM3 calculation and classical simulation the five stable adsorption sites of hydrogen atom are optimized inside a buckybowl C 36 H 12 , which are labeled as α-, β 1 -, β 2 -, γ-, and δ-carbons from edge to innermost carbon. In PIMD simulation, meanwhile, stable adsorption site is not appeared on δ-carbon, but on only α-, β 1 -, β 2 -, and γ-carbons. This result is due to the fact that the adsorbed hydrogen atom can easily go over the barrier for hydrogen transferring from δ- to β 1 -carbons by thermal and nuclear quantum fluctuations. The thermal and nuclear quantum effects are key role to settle the hydrogen adsorption sites on carbon materials.

  17. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Yoosefian, Mehdi, E-mail: m.yoosefian@kgut.ac.ir

    2017-01-15

    Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N{sub 2}O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N{sub 2}O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N{sub 2}O onto CNT, the horizontal adsorption with E{sub ads} = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N{sub 2}O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N{sub 2}O were investigated. Adsorption of N{sub 2}O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N{sub 2}O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N{sub 2}O sensors.

  18. Automatic Method for Controlling the Iodine Adsorption Number in Carbon Black Oil Furnaces

    Directory of Open Access Journals (Sweden)

    Zečević, N.

    2008-12-01

    Full Text Available There are numerous of different inlet process factors in carbon black oil furnaces which must be continuously and automatically adjusted, due to stable quality of final product. The most important six inlet process factors in carbon black oil-furnaces are:1. volume flow of process air for combustion2. temperature of process air for combustion3. volume flow of natural gas for insurance the necessary heat for thermal reaction of conversionthe hydrocarbon oil feedstock in oil-furnace carbon black4. mass flow rate of hydrocarbon oil feedstock5. type and quantity of additive for adjustment the structure of oil-furnace carbon black6. quantity and position of the quench water for cooling the reaction of oil-furnace carbon black.The control of oil-furnace carbon black adsorption capacity is made with mass flow rate of hydrocarbon feedstock, which is the most important inlet process factor. Oil-furnace carbon black adsorption capacity in industrial process is determined with laboratory analyze of iodine adsorption number. It is shown continuously and automatically method for controlling iodine adsorption number in carbon black oil-furnaces to get as much as possible efficient control of adsorption capacity. In the proposed method it can be seen the correlation between qualitatively-quantitatively composition of the process tail gasses in the production of oil-furnace carbon black and relationship between air for combustion and hydrocarbon feedstock. It is shown that the ratio between air for combustion and hydrocarbon oil feedstock is depended of adsorption capacity summarized by iodine adsorption number, regarding to BMCI index of hydrocarbon oil feedstock.The mentioned correlation can be seen through the figures from 1. to 4. From the whole composition of the process tail gasses the best correlation for continuously and automatically control of iodine adsorption number is show the volume fraction of methane. The volume fraction of methane in the

  19. Adsorption of Acid Red 57 from aqueous solutions onto polyacrylonitrile/activated carbon composite.

    Science.gov (United States)

    El-Bindary, Ashraf A; Diab, Mostafa A; Hussien, Mostafa A; El-Sonbati, Adel Z; Eessa, Ahmed M

    2014-04-24

    The adsorption of Acid Red 57 (AR57) onto Polyacrylonitrile/activated carbon (PAN/AC) composite was investigated in aqueous solution in a batch system with respect to contact time, pH and temperature. Physical characteristics of (PAN/AC) composite such as fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were obtained. Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were determined. The activation energy of adsorption was also evaluated for the adsorption of AR57 onto (PAN/AC) composite. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The dynamic data fitted the pseudo-second-order kinetic model well. The activation energy, change of free energy, enthalpy and entropy of adsorption were also evaluated for the adsorption of AR57 onto (PAN/AC) composite. The thermodynamics of the adsorption indicated spontaneous and exothermic nature of the process. The results indicate that (PAN/AC) composite could be employed as low-cost material for the removal of acid dyes from textile effluents. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Perchlorate adsorption and desorption on activated carbon and anion exchange resin.

    Science.gov (United States)

    Yoon, In-Ho; Meng, Xiaoguang; Wang, Chao; Kim, Kyoung-Woong; Bang, Sunbaek; Choe, Eunyoung; Lippincott, Lee

    2009-05-15

    The mechanisms of perchlorate adsorption on activated carbon (AC) and anion exchange resin (SR-7 resin) were investigated using Raman, FTIR, and zeta potential analyses. Batch adsorption and desorption results demonstrated that the adsorption of perchlorate by AC and SR-7 resin was reversible. The reversibility of perchlorate adsorption by the resin was also proved by column regeneration test. Solution pH significantly affected perchlorate adsorption and the zeta potential of AC, while it did not influence perchlorate adsorption and the zeta potential of resin. Zeta potential measurements showed that perchlorate was adsorbed on the negatively charged AC surface. Raman spectra indicated the adsorption resulted in an obvious position shift of the perchlorate peak, suggesting that perchlorate was associated with functional groups on AC at neutral pH through interactions stronger than electrostatic interaction. The adsorbed perchlorate on the resin exhibited a Raman peak at similar position as the aqueous perchlorate, indicating that perchlorate was adsorbed on the resin through electrostatic attraction between the anion and positively charged surface sites.

  1. Adsorption of Malachite Green dye onto activated carbon derived from Borassus aethiopum flower biomass.

    Science.gov (United States)

    Nethaji, S; Sivasamy, A; Thennarasu, G; Saravanan, S

    2010-09-15

    In the present study, chemically prepared activated carbon derived from Borassus aethiopum flower was used as adsorbent. Batch adsorption studies were performed for the removal of Malachite Green (MG) from aqueous solutions by varying the parameters like initial solution pH, adsorbent dosage, initial MG concentration and temperature with three different particle sizes such as 100 microm, 600 microm and 1000 microm. The zero point charge was 2.5 and the maximum adsorption occurred at the pH range from 6.0 to 8.0. Experimental data were analyzed by model equations such as Langmuir, Freundlich and Temkin isotherms and it was found that the Langmuir isotherm model best fitted the adsorption data. Thermodynamic parameters such as DeltaG, DeltaH and DeltaS were also calculated for the adsorption processes. Adsorption rate constants were determined using pseudo first-order, pseudo second-order rate equations and also Elovich model and intraparticle diffusion models. The results clearly showed that the adsorption of MG onto PFAC followed pseudo second-order model and the adsorption was both by film diffusion and by intraparticle diffusion. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Synthesis of silver sulfide modified carbon materials for adsorptive removal of dibenzothiophene in n-hexane.

    Science.gov (United States)

    Nazal, Mazen K; Khaled, Mazen; Aljundi, Isam H; Atieh, Muataz; Oweimreen, Ghassan A; Abulkibash, Abdalla M

    2017-12-01

    Carbon nanotube (CNT) and graphene oxide (GO) as common nanostructures were modified with silver sulfide (Ag 2 S) using chemical vapor deposition. The raw and modified materials were tested for the removal of Dibenzothiophene (DBT) from a model fuel in batch mode adsorption experiments. The maximum adsorption capacities of DBT were 52.18 and 49.65 mg g -1 , using CNT-Ag 2 S and GO-Ag 2 S, respectively. The adsorption isotherm was modeled using Freundlich, Langmuir and Temkin models using linear and non-linear regression. The squared correlation coefficient (R 2 ) and HYBRID error function were used to determine the best adsorption model. IR spectroscopy was used to study the DBT adsorption mechanism, and it was found that the DBT molecules lie flat on the surface of the developed adsorbents. Significant improvement was achieved in the adsorption of DBT using CNT-Ag2S and GO-Ag 2 S, where the maximum adsorption capacity increased by 127% and 117% respectively, which indicates a stronger interaction between DBT and the modified adsorbents.

  3. Removal of Phenol and o-Cresol by Adsorption onto Activated Carbon

    Directory of Open Access Journals (Sweden)

    A. Edwin Vasu

    2008-01-01

    Full Text Available A commercial activated carbon was utilized for the adsorptive removal of phenol and o-cresol from dilute aqueous solutions. Batch mode adsorption studies were performed by varying parameters such as concentration of phenol solution, time, pH and temperature. The well known Freundlich, Langmuir and Redlich-Peterson isotherm equations were applied for the equilibrium adsorption data and the various isotherm parameters were evaluated. The Langmuir monolayer adsorption capacities were found to be 0.7877 and 0.5936 mmole/g, respectively, for phenol and o-cresol. Kinetic studies performed indicate that the sorption processes can be better represented by the pseudo-second order kinetics. The processes were found to be endothermic and the thermodynamic parameters were evaluated. Desorption studies performed indicate that the sorbed phenol molecules can be desorbed with dil. HCl.

  4. Adsorptive removal of congo red dye from aqueous solution using bael shell carbon

    International Nuclear Information System (INIS)

    Ahmad, Rais; Kumar, Rajeev

    2010-01-01

    This study investigates the potential use of bael shell carbon (BSC) as an adsorbent for the removal of congo red (CR) dye from aqueous solution. The effect of various operational parameters such as contact time, temperature, pH, and dye concentration were studied. The adsorption kinetics was modeled by first-order reversible kinetics, pseudo-first-order kinetics, and pseudo-second-order kinetics. The dye uptake process obeyed the pseudo-second-order kinetic expression at pH 5.7, 7 and 8 whereas the pseudo-first-order kinetic model was fitted well at pH 9. Langmuir, Freundlich and Temkin adsorption models were applied to fit adsorption equilibrium data. The best-fitted data was obtained with the Freundlich model. Thermodynamic study showed that adsorption of CR onto BSC was endothermic in nature and favorable with the positive ΔH o value of 13.613 kJ/mol.

  5. Use of activated carbon adsorption in conjunction with radiation treatment processes

    International Nuclear Information System (INIS)

    Dickson, L.W.; Lopata, V.J.; Toft-Hall, A.; Kremers, W.; Singh, A.

    1988-01-01

    This report presents the results of an assessment of the potential applications of combined adsorption-irradiation treatment processes. The rationale for the study was to determine whether the cost of radiation treatment could be reduced by concentrating target species on an adsorbent in the radiation field. Several different studies on adsorption-irradiation treatment were identified in the literature, and experimental work was done on both the conversion of sulphur dioxide to elemental sulphur, and the removal of trihalomethanes from water by adsorption on activated carbon and subsequent irradiation. Adsorption-irradiation treatment would appear to be less costly than irradiation alone for radiolytic decomposition of target species at low concentration in liquid streams, in the presence of high-surface-area, electrically insulating adsorbents. 116 refs

  6. Kinetics and thermodynamics studies of silver ions adsorption onto coconut shell activated carbon.

    Science.gov (United States)

    Silva-Medeiros, Flávia V; Consolin-Filho, Nelson; Xavier de Lima, Mateus; Bazzo, Fernando Previato; Barros, Maria Angélica S D; Bergamasco, Rosângela; Tavares, Célia R G

    2016-12-01

    The presence of silver in the natural water environment has been of great concern because of its toxicity, especially when it is in the free ion form (Ag(+)). This paper aims to study the adsorption kinetics of silver ions from an aqueous solution onto coconut shell activated carbon using batch methods. Batch kinetic data were fitted to the first-order model and the pseudo-second-order model, and this last equation fits correctly the experimental data. Equilibrium experiments were carried out at 30°C, 40°C, and 50°C. The adsorption isotherms were reasonably fit using Langmuir model, and the adsorption process was slightly influenced by changes in temperature. Thermodynamic parameters (ΔH°, ΔG°, and ΔS°) were determined. The adsorption process seems to be non-favorable, exothermic, and have an increase in the orderness.

  7. Adsorption of a textile dye from aqueous solutions by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Fernando M.; Bergmann, Carlos P., E-mail: fernando.machado@hotmail.com.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Dept. de Materiais; Lima, Eder C.; Adebayo, Matthew A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Quimica; Fagan, Solange B. [Centro Universitario Franciscano (UNIFRA), Santa Maria, RS (Brazil). Area de Ciencias Tecnologicas

    2014-08-15

    Multi-walled and single-walled carbon nanotubes were used as adsorbents for the removal of Reactive Blue 4 textile dye from aqueous solutions. The adsorbents were characterised using Raman spectroscopy, N{sub 2} adsorption/desorption isotherms and scanning and transmission electron microscopy. The effects of pH, agitation time and temperature on adsorption capacity were studied. In the acidic pH region, the adsorption of the dye was favourable using both adsorbents. The contact time to obtain equilibrium isotherms at 298-323 K was fixed at 4 hours for both adsorbents. For Reactive Blue 4 dye, Liu isotherm model gave the best fit for the equilibrium data. The maximum sorption capacity for adsorption of the dye occurred at 323 K, attaining values of 502.5 and 567.7 mg g{sup -1} for MWCNT and SWCNT, respectively. (author)

  8. Adsorption of carbon dioxide in porous magnesium oxides

    International Nuclear Information System (INIS)

    Gutierrez B, E.

    2016-01-01

    Mg O powders were synthesized by chemical solution combustion and treated by mechanical milling, and separately were doped with Fe and Ni. The obtained powders were characterized by the X-ray diffraction (DRX) technique, scanning electron microscopy (Sem), elementary semi-quantitative analysis (EDS), N 2 physisorption measurements and infrared spectroscopy (IR). It was studied the CO 2 adsorption capacity in the synthesized materials as a function of temperature, pressure and saturation time. The results show that the CO 2 adsorption capacities on respective materials were 0.39 mmol/g in Mg O powders synthesized by chemical solution combustion, 1.61 mmol/g in Mg O powders treated by mechanical milling during 2.5 h, 0.90 mmol/g in Mg O powders doped with Fe by milling during 2.5 h and 1.50 mmol/g for Mg O powders doped with Ni milling during 7.5 h, at 25 degrees Celsius, 1 atm and 30 min of saturation time. The results showed that the powders treated by mechanical milling are efficient for CO 2 adsorption and are an alternative of advanced materials to be used as potential adsorbent materials and contribute to reduce the global warming. (Author)

  9. Noncatalytic hydrogenation of decene-1 with hydrogen accumulated in a hybrid carbon nanostructure in nanosized membrane reactors

    Science.gov (United States)

    Soldatov, A. P.

    2014-08-01

    Studies on the creation of nanosized membrane reactors (NMRs) of a new generation with accumulated hydrogen and a regulated volume of reaction zone were continued at the next stage. Hydrogenation was performed in the pores of ceramic membranes with hydrogen preliminarily adsorbed in mono- and multilayered orientated carbon nanotubes with graphene walls (OCNTGs)—a new hybrid carbon nanostructure formed on the inner pore surface. Quantitative determination of hydrogen adsorption in OCNTGs was performed using TRUMEM ultrafiltration membranes with D av = 50 and 90 nm and showed that hydrogen adsorption was up to ˜1.5% of the mass of OCNTG. The instrumentation and procedure for noncatalytic hydrogenation of decene-1 at 250-350°C using hydrogen accumulated and stored in OCNTG were developed. The conversion of decene-1 into decane was ˜0.2-1.8% at hydrogenation temperatures of 250 and 350°C, respectively. The rate constants and activation energy of hydrogenation were determined. The latter was found to be 94.5 kJ/mol, which is much smaller than the values typical for noncatalytic hydrogenations and very close to the values characteristic for catalytic reactions. The quantitative distribution of the reacting compounds in each pore regarded as a nanosized membrane reactor was determined. The activity of hydrogen adsorbed in a 2D carbon nanostructure was evaluated. Possible mechanisms of noncatalytic hydrogenation were discussed.

  10. Insight into the adsorption mechanisms of trace organic carbon on biological treatment process.

    Science.gov (United States)

    Zolfaghari, Mehdi; Drogui, Patrick; Brar, Satinder Kaur; Buelna, Gerardo; Dubé, Rino

    2017-09-01

    The presence of recalcitrant dissolved organic matter (DOM) could have a significant effect on the adsorption mechanism and capacity of the sludge for many trace organic carbons (TrOCs). In this study, adsorption of three TrOCs on the sludge and HA was investigated. The results revealed that neutral hydrophilic compounds had an insignificant interaction with both sludge and HA. Positively charged compounds, such as fluoranthene, had more affinity toward HA than sludge with solid/liquid partitioning of 57 and 3.2 L/g, respectively. The adsorption intensity (K f ) of di-2-ethyl hexyl phthalate was 0.5 and 1.13 for the HA and the sludge, respectively. By introducing the sludge to the solution of HA and TrOCs that already reached equilibrium, the sludge adsorption capacity in the presence of HA was investigated. The finding showed that at the lower concentration, adsorption of HA on the sludge was considered as the main removal pathway for the adsorbed emerging contaminants, as 70 mg of HA was adsorbed by a gram of sludge. For the higher concentration, desorption of TrOCs from DOM into the sludge comprised 15-30% of total removal efficiency. CBZ: carbamazepine; DEHP: di-2-ethyl hexyl phthalate; DOM: dissolved organic matter; FLAN: fluoranthene; f oc : fraction of organic carbon; HA: humic acid; Log Kow: octanol-water partition coefficient; PAH: polycyclic aromatic hydrocarbon TS: total solid; TrOCs: trace organic carbons VS: volatile solid.

  11. Adsorption of bentazon on CAT and CARBOPAL activated carbon: Experimental and computational study

    Science.gov (United States)

    Spaltro, Agustín; Simonetti, Sandra; Torrellas, Silvia Alvarez; Rodriguez, Juan Garcia; Ruiz, Danila; Juan, Alfredo; Allegretti, Patricia

    2018-03-01

    Removal of the bentazon by adsorption on two different types of activated carbon was investigated under various experimental conditions.Kinetics of adsorption is followed and the adsorption isotherms of the pesticide are determined. The effects of the changes in pH, ionic strength and temperature are analyzed. Computational simulation was employed to analyze the geometry and the energy of pesticide absorption on activated carbon. Concentration of bentazon decreases while increase all the variables, from the same initial concentration. Experimental data for equilibrium was analyzed by three models: Langmuir, Freundlich and Guggenheim-Anderson-de Boer isotherms. Pseudo-first and pseudo-second-order kinetics are tested with the experimental data, and pseudo-second-order kinetics was the best for the adsorption of bentazon by CAT and CARBOPAL with coefficients of correlation R2 = 0.9996 and R2 = 0.9993, respectively. The results indicated that both CAT and CARBOPAL are very effective for the adsorption of bentazon from aqueous solutions, but CAT carbon has the greater capacity.

  12. A study on hydrogen storage through adsorption in nano-structured carbons; Etude du stockage d'hydrogene par adsorption dans des carbones nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Langohr, D

    2004-10-15

    The aim of this work is to build and calibrate an experimental set-up for the testing of the materials, to produce some carbon materials in large amounts and characterise them, and finally, to test these materials in their ability to store hydrogen. This will help in establishing a link between the hydrogen storage capacities of the carbons and their nano-structure. The script is divided into four chapters. The first chapter will deal with the literature review on the thematic of hydrogen storage through adsorption in the carbon materials, while the second chapter will present the experimental set-up elaborated in the laboratory. The third chapter explains the processes used to produce the two families of carbon materials and finally, the last chapter presents the structural characterisation of the samples as well as the experimental results of hydrogen storage on the materials elaborated. (author)

  13. Carbon nanotubes based nafion composite membranes for fuel cell applications

    CSIR Research Space (South Africa)

    Cele, NP

    2009-01-01

    Full Text Available composite membranes. Keywords: Carbon Nanotubes, Conductivity, Fuel Cell, Nafion, Nanocomposite Membranes, Thermal Properties, Water Uptake FUEL CELLS 00, 0000, No. 0, 1–8 ? 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 ORIGINA L RESEAR CH PAPE... used strategies to overcome these drawbacks is the modification of Nafion by using polymer nanocomposite (PNC) technology. PNCs have recently shown a worldwide growth effort especially in the fabrication of high temperature PEM for fuel cells [18...

  14. Effects of carbon nanotubes on phosphorus adsorption behaviors on aquatic sediments.

    Science.gov (United States)

    Qian, Jin; Li, Kun; Wang, Peifang; Wang, Chao; Shen, Mengmeng; Liu, Jingjing; Tian, Xin; Lu, Bianhe

    2017-08-01

    Aquatic sediments are believed to be an important sink for carbon nanotubes (CNTs). With novel properties, CNTs can potentially disturb the fate and mobility of the co-existing contaminants in the sediments. Only toxic pollutants have been investigated previously, and to the best of our knowledge, no data has been published on how CNTs influence phosphorus (P) adsorption on aquatic sediments. In this study, multi-walled carbon nanotubes (MWCNTs) were selected as model CNTs. Experimental results indicated that compared to pseudo-first order and intraparticle diffusion models, the pseudo-second-order model is better for describing the adsorption kinetics of sediments and MWCNT-contaminated sediments. Adsorption isotherm studies suggested that the Langmuir model fits the isotherm data well. With the increase in the MWCNT-to-sediment ratio from 0.0% to 5.0%, the theoretical maximum monolayer adsorption capacity (Q max ) for P increased from 0.664 to 0.996mg/g. However, the Langmuir isotherm coefficient (K L ) significantly decreased from 4.231L/mg to 2.874L/mg, indicating the decrease in the adsorption free energy of P adsorbed on the sediments after MWCNT contamination. It was suggested that P was released more easily to the overlying water after the re-suspension of sediments. Moreover, the adsorption of sediments and sediment-MWCNT mixture was endothermic and physical in nature. Results obtained herein suggested that the change in the specific surface area and zeta potential of sediments is related to MWCNT contamination, and the large adsorption capacity of MWCNTs is probably the main factor responsible for the variation in the adsorption of P on aquatic sediments. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Sulfide treatment to inhibit mercury adsorption onto activated carbon in carbon-in-pulp gold recovery circuits

    Energy Technology Data Exchange (ETDEWEB)

    Touro, F.J.; Lipps, D.A.

    1988-03-29

    A process for treating a mercury-contaminated, precious metal-containing ore slurry is described comprising: (a) reacting sulfide anions in an aqueous ore slurry of a mercury and precious metal-containing carbonaceous ore, and (b) conducting a simultaneous cyanide leach and carbon-in-pulp adsorption of the precious metal from the carbonaceous ore in the sulfide-containing ore slurry.

  16. Adsorptive performance of granular activated carbon in aquaculture and aquaria: a simplified method

    DEFF Research Database (Denmark)

    Taylor, Daniel; Kuhn, David D.; Smith, Stephen

    2017-01-01

    and aquaculture is not well-established due to innate heterogeneity of these waters. The means to completely characterize adsorption between carbon sources are generally not available to end users provided their level of expertise and/or resources at their disposal. This study introduces a relatively simple...... used to comparatively test adsorptive performance between two filter groups (i.e. sources of granular activated carbon) by tracking spectral absorbance with non-linear regression statistics, and validating removal trends against mature aquaculture water. Greater adsorptive capacities were consistently...... observed in one filter group throughout the indicator testing battery. Similar findings were observed between the two indicator tests, thereby confirming the method. This method can be adopted by commercial aquaculture operations or aquarists to assist in comparatively screening particular types, particle...

  17. Studies on the adsorption of amoxicillin on multi-wall carbon nanotubes.

    Science.gov (United States)

    Balarak, Davoud; Mostafapour, FerdosKord; Bazrafshan, Edris; Saleh, Tawfik A

    2017-04-01

    This study examined the feasibility of removing amoxicillin (AMO) from aqueous solutions using multi-wall carbon nanotubes. The equilibrium adsorption data were analyzed using four widely applied isotherms: Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The results showed that the Langmuir isotherm model fits well the obtained experimental data. The adsorption process followed the pseudo-second-order model. The activation energy was found to be 19 kJ/mol. The Standard free energy changes, ΔG 0 , values were negative; the standard enthalpy change (ΔH 0 ), and standard entropy change (ΔS 0 ) values of the process were 4 kJ/mol and 36 J/mol.K. Results suggested that the AMO adsorption on carbon nanotubes was a spontaneous process.

  18. Porosity and adsorption properties of activated carbon derived from palm oil waste

    International Nuclear Information System (INIS)

    Che Seman Mahmood; Nor Hayati Alias; Choo Thye Foo; Megat Harun Al-Rashid Megat Ahmad

    2004-01-01

    Activated carbon have extensively been used as adsorbents in industry for the removal of pollutant species from gases for the purpose of purification and recovery of chemicals. The adsorption properties of the carbons depend very much on the porosity and type of pore presents which can be generated and controlled during synthesis and activation steps. This paper reports the effect of chemical activation by ZnCl 3 , KOH and nh 4 OH on the porosity of carbon produced from palm oil industry waste. Type of pores will further be validated by the SEM micrograph. The amount of gas adsorbed, the adsorption capacities can also be estimated based on the BET experiments data. The applicability of the produced carbon materials for the removal and exchange of hazardous incinerator gas is discussed. (Author)

  19. Chromate adsorption mechanism on nanodiamond-derived onion-like carbon

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Young-Jin [Center for Electronic Materials, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Choi, Keunsu [Computational Science Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Lee, Soonjae [Department of Earth and Environmental Sciences, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea (Korea, Republic of); Cho, Jung-Min [Center for Electronic Materials, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Department of Materials Science and Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul 120-749, Republic of Korea (Korea, Republic of); Choi, Heon-Jin [Department of Materials Science and Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul 120-749, Republic of Korea (Korea, Republic of); Hong, Seok Won [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Choi, Jae-Woo, E-mail: plead36@kist.re.kr [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Daejeon 305-350, Republic of Korea (Korea, Republic of); Mizuseki, Hiroshi, E-mail: mizuseki@kist.re.kr [Computational Science Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Lee, Wook-Seong, E-mail: wsleemk@gmail.com [Center for Electronic Materials, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of)

    2016-12-15

    The onion-like carbon (OLC) was prepared as adsorbent and tested for the removal of chromate ions from aqueous solutions. The OLC was thermally derived from nanodiamond by vacuum annealing at 1000-2000 °C. An investigation was conducted the chromate adsorption mechanism of OLC, by analysing the temperature-dependent evolution of the various oxygen-carbon bonds and the chemisorbed water by X-ray photo electron spectroscopy, as well as by the first principle calculation of the bond energies for relevant bond configurations. The present work demonstrated the importance of the carbon-oxygen bond type and carbon dangling bonds for chromate adsorption, as well as for other anionic heavy metals adsorbed from wastewater and sewage.

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

    Directory of Open Access Journals (Sweden)

    Suyanta Suyanta

    2016-04-01

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

  1. Continuum simulations of water flow in carbon nanotube membranes

    DEFF Research Database (Denmark)

    Popadić, A.; Walther, Jens Honore; Koumoutsakos, P-

    2014-01-01

    We propose the use of the Navier–Stokes equations subject to partial-slip boundary conditions to simulate water flows in Carbon NanoTube (CNT) membranes. The finite volume discretizations of the Navier–Stokes equations are combined with slip lengths extracted from molecular dynamics (MD) simulati......We propose the use of the Navier–Stokes equations subject to partial-slip boundary conditions to simulate water flows in Carbon NanoTube (CNT) membranes. The finite volume discretizations of the Navier–Stokes equations are combined with slip lengths extracted from molecular dynamics (MD...

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

    Directory of Open Access Journals (Sweden)

    Nelson Giovanny Rincón-Silva

    2015-01-01

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

  3. Competitive adsorption between benzene and ethylene dichloride on activated carbon: The importance of concentration

    Science.gov (United States)

    Miao, T.; Tang, H. M.; Cheng, Z. X.

    2018-03-01

    In this work we studied breakthroughs of binary mixtures of benzene and ethylene dichloride on fixed activated carbons bed. The results show a series of assault concentrations on activated carbon bed influences the nature of the adsorption competition mechanism. Assault concentration were used to determine how competition of compound distribution. The results are discussed in terms of competing energetic and the underlying molecular mechanisms. The ratio of assault concentrations is main reason for determining selectivity.

  4. Adsorption of NO{sub 2} on carbon aerosols particles at the low ppb-level

    Energy Technology Data Exchange (ETDEWEB)

    Kalberer, M.; Ammann, M.; Baltensperger, U.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The adsorption of NO{sub 2} at the low ppb-level (3-40 ppb) on carbon aerosol particles was investigated. A sticking coefficient of about 2.10{sup -4} was found, similar to that in previous studies using radioactively labeled {sup 13}NO{sub 2}. (author) 2 figs., 2 refs.

  5. Adsorption of Carbon Dioxide on Sodium and Potassium Forms of STI Zeolite

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Zones, S. I.; Kubů, Martin; Davis, T. M.; Čejka, Jiří

    2012-01-01

    Roč. 77, č. 8 (2012), s. 675-681 ISSN 2192-6506 R&D Projects: GA ČR GA203/08/0604 Institutional support: RVO:61388955 Keywords : adsorption * carbon dioxide * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry

  6. High Pressure Adsorption Isotherm of CO2 on Activated Carbon using Volumetric Method

    Directory of Open Access Journals (Sweden)

    Awaludin Martin

    2011-05-01

    Full Text Available Adsorption system is ones of the most effective methods for CO2 separating with other substances that produced from the burning of fossil fuels. In the design for that application, beside of characteristics of porous material (adsorbent data, CO2 adsorption data on the adsorbent (kinetic and thermodynamic are also needed. The aim of this research is resulting isothermal adsorption data at pressures up to 3.5 MPa by indirect methods (volumetric method at isothermal temperature of 300, 308, 318 and 338 K. Adsorbent that used in this research is activated carbon made from East of Kalimantan coals by physical activation method (CO2 which is the surface area of activated carbon is 668 m2/g and pore volume is 0.47 mL/g. Carbon dioxide (CO2 that used in this research is high purity carbon dioxide with a purity of 99.9%. Data from the experiment results then correlated using the Langmuir and Toth equations model. The results showed that the maximum adsorption capacity is 0.314 kg/kg at 300 K and 3384.69 kPa. The results of regression of experiment data using Langmuir and Toth models were 3.4% and 1.7%.

  7. Conductance of Sidewall-Functionalized Carbon Nanotubes: Universal Dependence on Adsorption Sites

    DEFF Research Database (Denmark)

    García-Lastra, J.M.; Thygesen, Kristian Sommer; Strange, Mikkel

    2008-01-01

    We use density functional theory to study the effect of molecular adsorbates on the conductance of metallic carbon nanotubes (CNT). The five molecules considered (NO2, NH2, H, COOH, OH) lead to very similar scattering of the electrons. The adsorption of a single molecule suppresses one of the two...

  8. CO2 Adsorption by para-Nitroaniline Sulfuric Acid-Derived Porous Carbon Foam

    Directory of Open Access Journals (Sweden)

    Enrico Andreoli

    2016-12-01

    Full Text Available The expansion product from the sulfuric acid dehydration of para-nitroaniline has been characterized and studied for CO2 adsorption. The X-ray photoelectron spectroscopy (XPS characterization of the foam indicates that both N and S contents (15 and 9 wt%, respectively are comparable to those separately reported for nitrogen- or sulfur-containing porous carbon materials. The analysis of the XPS signals of C1s, O1s, N1s, and S2p reveals the presence of a large number of functional groups and chemical species. The CO2 adsorption capacity of the foam is 7.9 wt% (1.79 mmol/g at 24.5 °C and 1 atm in 30 min, while the integral molar heat of adsorption is 113.6 kJ/mol, indicative of the fact that chemical reactions characteristic of amine sorbents are observed for this type of carbon foam. The kinetics of adsorption is of pseudo-first-order with an extrapolated activation energy of 18.3 kJ/mol comparable to that of amine-modified nanocarbons. The richness in functionalities of H2SO4-expanded foams represents a valuable and further pursuable approach to porous carbons alternative to KOH-derived activated carbons.

  9. Fixed-bed column adsorption of methyl blue using carbon derived ...

    African Journals Online (AJOL)

    Axle Wood Carbon (AWC) was used to study the removal of Methyl Blue (MB) from its aqueous solution in a fixed-bed column adsorption system. The adsorbent (AWC) was characterized using SEM and pHPZC. SEM revealed the surface morphology and from the pHPZC determination, it was found that at pH of 8.21 the ...

  10. Effect of dissolved organic carbon in recycled wastewaters on boron adsorption by soils

    Science.gov (United States)

    In areas of water scarcity, recycled municipal wastewaters are being used as water resources for non-potable applications, especially for irrigation. Such wastewaters often contain elevated levels of dissolved organic carbon (DOC) and solution boron (B). Boron adsorption was investigated on eight ...

  11. Adsorption of Selected Pharmaceutical Compounds onto Activated Carbon in Dilute Aqueous Solutions Exemplified by Acetaminophen, Diclofenac, and Sulfamethoxazole

    Science.gov (United States)

    Chang, E.-E.; Wan, Jan-Chi; Liang, Chung-Huei; Dai, Yung-Dun; Chiang, Pen-Chi

    2015-01-01

    The adsorption of three pharmaceuticals, namely, acetaminophen, diclofenac, and sulfamethoxazole onto granular activated carbon (GAC), was investigated. To study competitive adsorption, both dynamic and steady-state adsorption experiments were conducted by careful selection of pharmaceuticals with various affinities and molecular size. The effective diffusion coefficient of the adsorbate was increased with decease in particle size of GAC. The adsorption affinity represented as Langmuir was consistent with the ranking of the octanol-water partition coefficient, K ow. The adsorption behavior in binary or tertiary systems could be described by competition adsorption. In the binary system adsorption replacement occurred, under which the adsorbate with the smaller K ow was replaced by the one with larger K ow. Results also indicated that portion of the micropores could be occupied only by the small target compound, but not the larger adsorbates. In multiple-component systems the competition adsorption might significantly be affected by the macropores and less by the meso- or micropores. PMID:26078989

  12. Influence of the particle size of activated mineral carbon on the phenol and chlorophenol adsorption

    International Nuclear Information System (INIS)

    Garcia M, A.

    2001-01-01

    Water pollution by phenolic compounds is a problem that requires a solution since these phenolic compounds are not completely biodegradable, they accumulate through the food chains and they are quite toxic when enter in contact with living organisms. In human beings, ingestion or contact of the skin with this type of compounds produces irritation and damages mainly to the liver and kidneys. In fact, the Environmental Protection Agency of the United States (EPA assigned nine phenolic compounds among the 275 most toxic substances in 1991. Phenols are found in wastewater from agriculture and industry, because phenolic compounds are used as pesticides and in diverse industrial activities. The treatment of this type of water is not simple because they are generally composed of a mixture of residuals with different chemical nature A useful method for the removal of phenols is the adsorption by activated carbon, since this material has a great surface area and it can be regenerated. The adsorption process depends, among other factors, on the activated carbon characteristics. When they are modified, their capacity to remove pollutants from the water changes. The effect of activated carbon particle size on the removal of phenolic compounds has not been completely studied. Therefore, the aim of this work was to determine the influence of the mineral activated carbon particle size on the phenol and 4-chloro phenol adsorption in aqueous solution, on adsorption column system. The results of the present work indicate that the mineral activated carbon particle size has a very important influence on the adsorption of phenol and 4-chloro phenol. When the particles were smaller, the retention quantities of phenol and 4-chloro phenol increased. This behavior was related to the particle characteristics of the mineral activated carbon such as surface area and pore volume, while other factors such as elementary composition of the activated carbon did not influence the adsorption process

  13. Measurements of Increased Enthalpies of Adsorption for Boron-Doped Activated Carbons

    Science.gov (United States)

    Gillespie, Andrew; Beckner, Matthew; Chada, Nagaraju; Schaeperkoetter, Joseph; Singh, Anupam; Lee, Mark; Wexler, Carlos; Burress, Jacob; Pfeifer, Peter

    2013-03-01

    Boron-doping of activated carbons has been shown to increase the enthalpies of adsorption for hydrogen as compared to their respective undoped precursors (>10kJ/mol compared to ca. 5kJ/mol). This has brought significant interest to boron-doped carbons for their potential to improve hydrogen storage. Boron-doped activated carbons have been produced using a process involving the deposition of decaborane (B10H14) and high-temperature annealing resulting in boron contents up to 15%. In this talk, we will present a systematic study of the effect that boron content has on the samples' structure, hydrogen sorption, and surface chemistry. Measurements have shown a significant increase in the areal hydrogen excess adsorption and binding energy. Experimental enthalpies of adsorption will be presented for comparison to theoretical predictions. Additionally, samples have been characterized by thermal gravimetric analysis, gas chromatography-mass spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. TGA and GC-MS results investigated the decomposition of the decaborane in the carbon. Boron-carbon bonds are shown in the FTIR and XPS spectra, indicating that boron has been incorporated into the carbon matrix. Work supported by DOE-EERE, Award No. DE-FG36-08GO18142

  14. Adsorption of pertechnetate ion on various active carbons from mineral acid solutions

    International Nuclear Information System (INIS)

    Ito, K.

    1991-01-01

    The adsorption behavior of pertechnetate ion (TcO 4 - ) on active carbon has been studied for various acid solutions, taking as indicative value the distribution coefficient K d of Tc between active carbon surface and solution. In a system where the total anion concentration of the acid and its sodium salt was maintained constant, modifying the pH of the solution proved distinctly to influence the Tc adsorption behavior of active carbon: taking the case of active carbon derived from coconut shell, increasing the acidity raised K d ; around neutrality there occurred a level stage; in the alkali region, K d declined. The rise of K d in the acid region, however, was observed only with active carbon derived from coconut shell, from oil pitch or from saw dust; it failed to occur when the active carbon was derived from coal or from bone. With a hydrochloric acid system, the rise of K d started around 1 M (mol dm -1 ) HCl. Beyond 3 M, on the other hand, a breakthrough occurred, and K d declined with increasing acidity. With a nitric acid system, K d rose from 1 M, and the breakthrough occurred at 2 M. When the adsorption was left to equilibrate beyond 4 h, desorption displacement of TcO 4 - by a coexisting other anion was observed in the case of perchloric acid solutions of concentration above 0.1 M and with sulfuric acid solutions above 0.5 M. (author)

  15. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2007-04-01

    Supported liquid membranes are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties as a direct guide in the development of a capture technology. These membranes also have the advantage of liquid phase diffusivities higher than those observed in polymeric membranes which grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high carbon dioxide solubility relative to light gases such as hydrogen, are an excellent candidate for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of several ionic liquids, including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide, 1-butyl-3-methyl-imidazolium nitrate, and 1-ethyl-3-methyl-imidazolium sulfate in supported ionic liquid membranes for the capture of carbon dioxide from streams containing hydrogen. In a joint project, researchers at the University of Notre Dame lent expertise in ionic liquid synthesis and characterization, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Initial results have been very promising with carbon dioxide permeabilities as high as 950 barrers and significant improvements in carbon dioxide/hydrogen selectivity over conventional polymers at 37C and at elevated temperatures. Results include a comparison of the performance of several ionic liquids and a number of supports as well as a discussion of innovative fabrication techniques currently under development.

  16. Relation between interfacial energy and adsorption of organic micropollutants onto activated carbon

    KAUST Repository

    De Ridder, David J.

    2013-03-01

    The adsorption efficacy of 16 pharmaceuticals on six different activated carbons is correlated to the thermodynamic work of adhesion, which was derived following the surface tension component approach. Immersion calorimetry was used to determine the surface tension components of activated carbon, while contact angle measurements on compressed plates were used to determine these for solutes. We found that the acid-base surface tension components of activated carbon correlated to the activated carbon oxygen content. Solute-water interaction correlated well to their solubility, although four solutes deviated from the trend. In the interaction between solute and activated carbon, van der Waals interactions were dominant and explained 65-94% of the total interaction energy, depending on the hydrophobicity of the activated carbon and solute. A reasonable relationship (r2 > 70) was found between the calculated work of adhesion and the experimentally determined activated carbon loading. © 2012 Elsevier Ltd. All rights reserved.

  17. pH-dependence of pesticide adsorption by wheat-residue-derived black carbon.

    Science.gov (United States)

    Yang, Yaning; Chun, Yuan; Sheng, Guangyao; Huang, Minsheng

    2004-08-03

    The potential of black carbon as an adsorbent for pesticides in soils may be strongly influenced by the properties of the adsorbent and pesticides and by the environmental conditions. This study evaluated the effect of pH on the adsorption of diuron, bromoxynil, and ametryne by a wheat (Triticum aestivum L.) residue derived black carbon (WC) as compared to a commercial activated carbon (AC). The pH drift method indicated that WC had a point of zero charge of 4.2, much lower than that of 7.8 for AC. The density of oxygen-containing surface functional groups, measured by the Boehm titration, on WC was 5.4 times higher than that on AC, resulting in a pesticide adsorption by WC being 30-50% of that by AC, due to the blockage of WC surface by the waters associated with the functional groups. A small decrease (5.5%/unit pH) in diuron adsorption by WC with increase in pH resulted from increased deprotonation of surface functional groups at higher pH values. A much larger decrease (14-21%/unit pH) in bromoxynil adsorption by WC with increase in pH resulted from the deprotonation of both the adsorbate and surface functional groups of the adsorbent. The deprotonation reduced the adsorptive interaction between bromoxynil and the neutral carbon surface and increased the electrical repulsion between the negatively charged WC surface and bromoxynil anions. Deprotonation of ametryne with increase in pH over the low pH range increased its fraction of molecular form and thus adsorption on WC by 15%/unit pH. Further increase in pH resulted in a 20%/unit pH decrease in ametryne adsorption by WC due primarily to the development of a negative charge on the surface of WC. The pH-dependent adsorption of pesticides by black carbon may significantly influence their environmental fate in soils.

  18. An investigation of groundwater organics, soil minerals, and activated carbon on the complexation, adsorption, and separation of technetium-99

    Energy Technology Data Exchange (ETDEWEB)

    Gu, B. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Dowlen, K.E. [Oak Ridge Associated Universities, TN (United States)

    1996-01-01

    This report summarizes studies on the interactions of technetium-99 (Tc) with different organic compounds and soil minerals under both oxidizing and reducing conditions. The report is divided into four parts and includes (1) effect of natural organic matter (NOM) on the complexation and solubility of Tc, (2) complexation between Tc and trichloroethylene (TCE) in aqueous solutions, (3) adsorption of Tc on soil samples from Paducah Gaseous Diffusion Plant (PGDP), and (4) adsorption and separation of Tc on activated carbon. Various experimental techniques were applied to characterize and identify Tc complexation with organic compounds and TCE, including liquid-liquid extraction, membrane filtration, size exclusion, and gel chromatography. Results indicate, within the experimental error, Tc (as pertechnetate, TcO{sub 4}) did not appear to form complexes with groundwater or natural organic matter under both atmospheric and reducing conditions. However, Tc can form complexes with certain organic compounds or specific functional groups such as salicylate. Tc did not appear to form complexes with TCE in aqueous solution.Both liquid-liquid extraction and high performance liquid chromatography (HPLC) gave no indication Tc was complexed with TCE. The correlations between Tc and TCE concentrations in monitoring wells at PGDP may be a coincidence because TCE was commonly used as a decontamination reagent. Once TCE and Tc entered the groundwater, they behaved similarly because both TcO{sub 4}{sup {minus}} and TCE are poorly adsorbed by soils. An effective remediation technique to remove TcO{sub 4}{sup {minus}} from PGDP contaminated groundwater is needed. One possibility is the use of an activated carbon adsorption technique developed in this study.

  19. A model of mitochondrial creatine kinase binding to membranes: adsorption constants, essential amino acids and the effect of ionic strength

    DEFF Research Database (Denmark)

    Fedosov, Sergey; Belousova, Lubov; Plesner, Igor

    1993-01-01

    of mitCK adsorption capacity by another method at pH 7.4, when the enzyme is almost protonated, gave View the MathML source. The effect of ionic strength on mitCK adsorption may be described in terms of Debye-Hückel's theory for activity coefficients assuming the charges of the interacting species......The quantitative aspects of mitochondrial creatinekinase (mitCK) binding to mitochondrial membranes were investigated. A simple adsorption and binding model was used for data fitting, taking into account the influence of protein concentration, pH, ionic strength and substrate concentration...... on the enzyme adsorption. An analysis of our own data as well as of the data from the literature is consistent with the adsorption site of the octameric mitCK being composed of 4 amino acid residues with pK = 8.8 in the free enzyme. The pK value changes to 9.8 upon binding of the protein to the membrane. Lysine...

  20. Synthesis and characterization of carbon nano fibers for its application in the adsorption of toxic gases

    International Nuclear Information System (INIS)

    Juanico L, J.A.

    2004-01-01

    The production of carbon nano fibers (CNF's) by diverse techniques as the electric arc, laser ablation, or chemical deposition in vapor phase, among other, they have been so far used from final of the 90's. However, the synthesis method by discharge Glow arc of alternating current and high frequency developed by Pacheco and collaborators, is a once alternative for its obtaining. In the plasma Application Laboratory (LAP) of the National Institute of Nuclear Research (INlN) it was designed and manufactured a reactor of alternating current and high frequency that produces a Glow arc able to synthesize carbon nano fibers. Its were carried out nano fibers synthesis with different catalysts to different proportions and with distinct conditions of vacuum pressure and methane flow until obtaining the best nano fibers samples and for it, this nano structures were characterized by Scanning and Transmission Electron Microscopy, X-ray Diffraction, Raman spectrometry and EDS spectrometry. Once found the optimal conditions for the nano fibers production its were contaminated with NO 2 toxic gas and it was determined if they present adsorption, for it was used the thermal gravimetric analysis technique. This work is divided in three parts, in the first one, conformed by the chapters 1, at the 3, they are considered the foundations of the carbon nano fibers, their history, their characteristics, growth mechanisms, synthesis techniques, the thermal gravimetric analysis principles and the adsorption properties of the nano fibers. In the second part, consistent of the chapters 4 and 5, the methodology of synthesis and characterization of the nano fibers is provided. Finally, in third part its were carried out the activation energy calculation, the adsorption of the CNF's is analyzed and the conclusions are carried out. The present study evaluates the adsorption of environmental gas pollutants as the nitrogen oxides on carbon nano fibers at environmental or near conditions. Also

  1. Oil Spill Adsorption Capacity of Activated Carbon Tablets from Corncobs in Simulated Oil-Water Mixture

    Directory of Open Access Journals (Sweden)

    Rhonalyn V. Maulion

    2015-12-01

    Full Text Available Oil spill in bodies of water is one of severe environmental problems that is facing all over the country and in the world. Since oil is an integral part of the economy, increasing trend for its demand and transport of has led to a great treat in the surface water. One of the promising techniques in the removal of the oil spills in water bodies is adsorption using activated carbon form waste material such as corn cobs. The purpose of this study is to determine the adsorption capacity of activated carbon tablets derived from corncobs in the removal of oil. The properties of activated carbon produced have a pH of 7.0, bulk density of 0.26 g//cm3 , average pore size of 45nm, particle size of 18% at 60 mesh and 39% at 80 mesh, iodine number of 1370 mg/g and surface area of 1205 g/m2. The amount of bentonite clay as binder (15%,20%,30%, number of ACT (1,2,3 and time of contact(30,60,90 mins has been varied to determine the optimum condition where the activated carbon will have the best adsorption capacity in the removal of oil. Results showed that at 15% binder, 60 mins contact time and 3 tablets of activated carbon is the optimum condition which give a percentage adsorption of 22.82% of oil. Experimental data also showed that a Langmuir isotherm was the best fit isotherm for adsorption of ACT.

  2. Adsorption of butane isomers and SF6 on Kureha activated carbon: 1. Equilibrium.

    Science.gov (United States)

    Zhu, Weidong; Groen, Johan C; Kapteijn, Freek; Moulijn, Jacob A

    2004-06-22

    Adsorption equilibria of butane isomers and SF6 on Kureha activated carbon were investigated using the volumetric method and the tapered element oscillating microbalance (TEOM) technique. The isotherm data of the butane isomers measured by the TEOM technique are in good agreement with those determined by the volumetric method. Single-component adsorption isotherms are reported at temperatures in the range from 298 to 393 K and at pressures up to 120 kPa. SF6 molecules are mainly adsorbed in the larger micropores, resulting in a lower adsorption capacity. The amount adsorbed for n-butane is slightly higher than that for isobutane in the whole range investigated. This is attributed to the fact that the linear n-butane molecule can adsorb in the smaller micropores. The T6th model appropriately describes the equilibrium data of the butane isomers, while the isotherm data of SF6 can be fitted by the Langmuir model. The isosteric heats associated with adsorption for these three adsorptives show different loading dependences. The present study indicates that the activated carbon can be well characterized by the probe molecules having different molecular sizes.

  3. Characteristics of activated carbon fibers concerning 1,1,1-trichloroethane adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Tanada, S.; Shinoda, S.; Nakamura, T. (Kinki Univ., Osaka (Japan). Faculty of Pharmaceutical Sciences)

    1992-01-10

    In spite of excellent industrial features, l,l,l-trichloroethane (methylchloroform: MC) together with trichloroethylene(TCE) and perchloroethylene(PCE) is now subject to the criterion for draining set by Government agencies due to their toxicities. It was studied that the performance of adsorption of mc onto activated carbon fibers (ACFs)in gaseous phase for purpose of prevention against the air polution and inhalation of carcinogenic compound by workers. In experiments, in addition to 6 kinds of ACFs, a granular activated carbon (GAC) and 95% MC were used. The adsorption isotherm of MC onto ACF or GAC was determined in an all-glass vacuum system and the amount adsorbed were measured by using a B.E.T. apparatus with a spring balance. And the specific surface area and the pore size distribution of ACF or GAG were measured with a B.E.T. apparatus by using super high purity nitrogen gas. As a result, it was found that the adsorption capacities of ACFs were large according to their grade number and the amount absorbed was so large as lower temperature, which was considered to be a physical adsorption. Furthermore, applying the Dubinin-Radushkevich(D-R) equation to the adsorption isotherms,AGFs could be classified into 2 types according to the adsortion sites of MC.11 refs., 6 figs., 2 tabs.

  4. Comparative study of the adsorption of acetaminophen on activated carbons in simulated gastric fluid.

    Science.gov (United States)

    Rey-Mafull, Carlos A; Tacoronte, Juan E; Garcia, Raquel; Tobella, Jorge; Llópiz, Julio C; Iglesias, Alberto; Hotza, Dachamir

    2014-01-01

    Samples of commercial activated carbons (AC) obtained from different sources: Norit E Supra USP, Norit B Test EUR, and ML (Baracoa, Cuba) were investigated. The adsorption of acetaminophen, Co = 2500 mg/L, occured in simulated gastric fluid (SGF) at pH 1.2 in contact with activated carbon for 4 h at 310 K in water bath with stirring. Residual acetaminophen was monitored by UV visible. The results were converted to scale adsorption isotherms using alternative models: Langmuir TI and TII, Freundlich, Dubinin-Radushkevich (DR) and Temkin. Linearized forms of the characteristic parameters were obtained in each case. The models that best fit the experimental data were Langmuir TI and Temkin with R(2) ≥0.98. The regression best fits followed the sequence: Langmuir TI = Temkin > DR > LangmuirTII > Freundlich. The microporosity determined by adsorption of CO2 at 273 K with a single term DR regression presented R(2) > 0.98. The adsorption of acetaminophen may occur in specific sites and also in the basal region. It was determined that the adsorption process of acetaminophen on AC in SGF is spontaneous (ΔG <0) and exothermic (-ΔHads.). Moreover, the area occupied by the acetaminophen molecule was calculated with a relative error from 7.8 to 50%.

  5. Adsorption of rhodamine B by acid activated carbon-Kinetic, thermodynamic and equilibrium studies

    Directory of Open Access Journals (Sweden)

    Shanmugam Arivoli

    2009-08-01

    Full Text Available A carbonaceous adsorbent prepared from an indigenous waste by acid treatment was tested for its efficiency in removing Rhodamine B (RDB. The parameters studied include agitation time, initial dye concentration, carbon dose, pH and temperature. The adsorption followed first order kinetics and the rate is mainly controlled by intra-particle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm obtained from the Langmuir isotherm plots were 40.161, 35.700, 38.462 and 37.979 mg/g respectively at an initial pH of 7.0 at 30, 40, 50 and 60 0C. The temperature variation study showed that the RDB adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the RDB solutions. Almost 85% removal of RDB was observed at 60 0C. The Langmuir and Freundlich isotherms obtained, positive ?H0 value, pH dependent results and desorption of dye in mineral acid suggest that the adsorption of RDB by Banana bark carbon involves physisorption mechanism.

  6. Poly-thiosemicarbazide Membrane for Gold Adsorption and In-situ Growth of Gold Nanoparticles

    KAUST Repository

    Parra, Luis F.

    2012-12-01

    In this work the synergy between a polymer containing chelate sites and gold ions was explored by the fabrication of a polymeric membrane with embedded gold nanoparticles inside its matrix and by developing a process to recover gold from acidic solutions. After realizing that the thiosemicarbazide groups present in the monomeric unit of poly-thiosemicarbazide (PTSC) formed strong complexes with Au ions, membrane technology was used to exploit this property to its maximum. The incorporation of metal nanoparticles into polymeric matrices with current technologies involves either expensive and complicated procedures or leads to poor results in terms of agglomeration, loading, dispersion, stability or efficient use of raw materials. The fabrication procedure described in this thesis solves these problems by fabricating a PTSC membrane containing 33.5 wt% in the form of 2.9 nm gold nanoparticles (AuNPs) by a three step simple and scalable procedure. It showed outstanding results in all of the areas mentioned above and demonstrated catalytic activity for the reduction of 4-Nitrophenol (4−NP) to 4-Aminophenol (4−AP). The current exponential demand of gold for electronics has encouraged the development of efficient processes to recycle it. Several adsorbents used to recover gold from acidic solutions can be found in the literature with outstanding maximum uptakes,yet, poor kinetics leading to an overall inefficient process. The method developed in this dissertation consisted in permeating the gold-containing solution through a PTSC membrane that will capture all the Au ions by forming a metal complex with them. Forcing the ions through the pores of the membrane eliminates the diffusion limitations and the adsorption will only depended on the fast complexation kinetics, resulting in a very efficient process. A flux as high as 1868 L/h m2 was enough to capture >90% of the precious metal present in a solution of 100 ppm Au. The maximum uptake achieved without sacrificing

  7. Adsorption of Chromium Ions by Acid Activated Low Cost Carbon-Kinetic,Thermodynamic and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    B. R. Venkatraman

    2009-01-01

    Full Text Available A carbonaceous adsorbent prepared from an indigenous waste, by acid treatment was tested for its efficiency in removing metal ions. The process parameters studied include agitation time, initial metal ions concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intra-particle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm obtained from the Langmuir isotherm plot were found to around 30 mg/g at an initial pH of 7.0. The temperature variation study showed that the metal ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the metal ion solutions. The Langmuir and Freundlich adsorption isotherms obtained, positive ΔH0 value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of metal ions on BBC involves chemisorption as well as physisorption mechanism.

  8. Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

    Science.gov (United States)

    Romero-Hermida, M. I.; Romero-Enrique, J. M.; Morales-Flórez, V.; Esquivias, L.

    2016-08-01

    Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N2, CO2, and O2, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO2 adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO2 adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO2 adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO2 adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO2 concentrations and low temperatures, the CO2 adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

  9. Removal of copper ions from wastewater by adsorption/electrosorption on modified activated carbon cloths

    International Nuclear Information System (INIS)

    Huang, Chen-Chia; Su, Yu-Jhih

    2010-01-01

    Adsorption and electrosorption of copper ions (Cu 2+ ) from wastewater were investigated with variously modified activated carbon fiber (ACF) cloth electrodes. Commercial polyacrylonitrile-based ACF cloths were modified by nitric acid or impregnated with chitosan solution. The surface characteristics of ACFs before and after modification were evaluated by nitrogen adsorption-desorption isotherms, zeta potential, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. Adsorption and electrosorption capacities of Cu 2+ on ACF cloths without and with a bias potential were measured, respectively, and the electrosorption isotherms were also investigated. The initial pH of the copper ion solution was adjusted to 4.0. Experimental results showed that electrosorption effectively increases adsorption capacity. The adsorption/electrosorption isotherms of Cu 2+ on ACF cloths were in good agreement with Langmuir and Freundlich equations. The equilibrium adsorption capacity at 0.3 V was 0.389 mmol/g, which is two times higher than that at open circuit. The maximum electrosorption capacity of Cu 2+ on chitosan impregnated ACF cloths was 0.854 mmol/g, which is about 2.2 times higher than that on the pristine cloths.

  10. Dibenzothiophene adsorption at boron doped carbon nanoribbons studied within density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    López-Albarrán, P. [Facultad de Ingeniería en Tecnología de la Madera, Universidad Michoacana de San Nicolás de Hidalgo, Santiago Tapia 403, CP 58000, Morelia, Michoacán (Mexico); Navarro-Santos, P., E-mail: pnavarrosa@conacyt.mx [Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Santiago Tapia 403, CP 58000, Morelia, Michoacán (Mexico); Garcia-Ramirez, M. A. [Research Centre for Innovation in Aeronautical Engineering, Universidad Autónoma de Nuevo León, Ciudad Universitaria, San Nicolás de los Garza, CP 66451 Nuevo León (Mexico); Ricardo-Chávez, J. L. [Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Lomas 4" asección, CP 78216, San Luis Potosí, S. L. P. (Mexico)

    2015-06-21

    The adsorption of dibenzothiophene (DBT) on bare and boron-doped armchair carbon nanoribbons (ACNRs) is being investigated in the framework of the density functional theory by implementing periodic boundary conditions that include corrections from dispersion interactions. The reactivity of the ACNRs is characterized by using the Fukui functions as well as the electrostatic potential as local descriptors. Non-covalent adsorption mechanism is found when using the local Perdew-Becke-Ernzerhof functional, regardless of the DBT orientation and adsorption location. The dispersion interactions addition is a milestone to describe the adsorption process. The charge defects introduced in small number (i.e., by doping with B atoms), within the ACNRs increases the selectivity towards sulfur mainly due to the charge depletion at B sites. The DBT magnitude in the adsorption energy shows non-covalent interactions. As a consequence, the configurations where the DBT is adsorbed on a BC{sub 3} island increase the adsorption energy compared to random B arrangements. The stability of these configurations can be explained satisfactorily in terms of dipole interactions. Nevertheless, from the charge-density difference analysis and the weak Bader charge-distribution interactions cannot be ruled out completely. This is why the electronic properties of the ribbons are analyzed in order to elucidate the key role played by the B and DBT states in the adsorbed configurations.

  11. Modeling of the thermal effects of hydrogen adsorption on activated carbon

    International Nuclear Information System (INIS)

    Richard, M.-A.; Chahine, R.

    2006-01-01

    'Full text:' Heat management is one of the most critical issues for the design of efficient adsorption-based storage of hydrogen. We present simulations of mass and energy balance for hydrogen and nitrogen adsorption on activated carbon over wide temperature and pressure ranges. First, the Dubinin-Astakhov (DA) model is adapted to model excess hydrogen and nitrogen adsorption isotherms at high pressures and supercritical temperatures assuming a constant microporous adsorption volume. The five parameter modified D-A adsorption model is shown to fit the experimental data over the temperature range (35 K-293 K) for hydrogen and (93 K-298 K) for nitrogen and pressure range (0-6 MPa) within the experimental uncertainties of the measurement system. We derive the thermodynamic properties of the adsorbed phase from this analytical expression of the measured data. The mass and energy rate balance equations in a microporous adsorbent/adsorbate system are then presented and validated with nitrogen desorption experiments. Finally, simulations of adiabatic and isothermal filling of adsorption-based hydrogen storage are presented and discussed. (author)

  12. Adsorptive removal of nickel from aqueous solutions by activated carbons from doum seed (Hyphaenethebaica coat

    Directory of Open Access Journals (Sweden)

    Manal El-Sadaawy

    2014-06-01

    Full Text Available The present study investigates the possibility of using low cost agriculture waste as doum-palm seed coat for the removal of nickel ions from aqueous solutions. Two activated carbons had been prepared from raw doum-palm seed coat (DACI and DACII; as well, the raw material was used as an adsorbent (RD. Batch adsorption experiments were performed as a function of pH of solution, initial nickel ions concentration, dose of adsorbent and contact time. Adsorption data were modeled using Langmuir, Freundlich, Temkin and D–R Models. Different error analysis conforms that the isotherm data followed Freundlich models for all adsorbents. Adsorption kinetic data were tested using pseudo-first order, pseudo-second order and Elovich model. Adsorption mechanism was investigated using the intra-particle diffusion model. Diffusion coefficients were calculated using the film and intraparticle diffusion models. Kinetic studies showed that the adsorption of Ni2+ ions onto RD, DACI and DACII followed pseudo-second order kinetic model, and indicates that the intra-particle diffusion controls the rate of adsorption but it is not the rate limiting step.

  13. Adsorption of lead(II) from water by carbon nanotubes: equilibrium, kinetics, and thermodynamics.

    Science.gov (United States)

    Rahbari, Meysam; Goharrizi, Ataallah Soltani

    2009-06-01

    Adsorption of lead(II) from water on carbon nanotubes (CNTs) was investigated using a series of batch adsorption experiments. The adsorption rate was studied experimentally at various temperatures, contact times, and initial pH and lead(II) concentrations. It was observed that a considerable amount of lead(II) was adsorbed during the first 5 minutes of contact time. The pH of the solution strongly influenced the amount of adsorption, and the best results were obtained when pH value was approximately 6. For the adsorption isotherm, the experimental data were analyzed by three two-parameter isotherms (Langmuir, Freundlich, and Temkin) and four three-parameter isotherms (Redhich-Peterson, Sips, Toth, and Khan). The three kinetic models used to test the experimental data were Lagergren first-order, second-order, and the Elovich equation. The results obtained from the study of the thermodynamic parameters showed that the adsorption of lead(II) onto CNTs was a spontaneous and endothermic process.

  14. Palm oil mill effluent treatment using coconut shell – based activated carbon: Adsorption equilibrium and isotherm

    Directory of Open Access Journals (Sweden)

    Kaman Sherlynna Parveen Deshon

    2017-01-01

    Full Text Available The current ponding system applied for palm oil mill effluent (POME treatment often struggle to comply with the POME discharge limit, thus it has become a major environmental concern. Batch adsorption study was conducted for reducing the Chemical Oxygen Demand (COD, Total Suspended Solids (TSS and Color of pre-treated POME using coconut shell-based activated carbon (CS-AC. The CS-AC showed BET surface area of 744.118 m2/g, with pore volume of 04359cm3/g. The adsorption uptake was studied at various contact time and POME initial concentration. The CS-AC exhibited good ability with average percentage removal of 70% for COD, TSS and Color. The adsorption uptake increased over time and attained equilibrium in 30 hours. The equilibrium data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Based on the coefficient regression and sum of squared errors, the Langmuir isotherm described the adsorption of COD satisfactorily, while best described the TSS and Color adsorption; giving the highest adsorption capacity of 10.215 mg/g, 1.435 mg/g, and 63.291 PtCo/g respectively. The CS-AC was shown to be a promising adsorbent for treating POME and was able to comply with the Environmental Quality Act (EQA discharge limit. The outcome of treated effluent using CS-AC was shown to be cleaner than the industrial biologically treated effluent, achieved within shorter treatment time.

  15. Adsorption and desorption of dissolved organic matter by carbon nanotubes: Effects of solution chemistry.

    Science.gov (United States)

    Engel, Maya; Chefetz, Benny

    2016-06-01

    Increasing use of carbon nanotubes (CNTs) has led to their introduction into the environment where they can interact with dissolved organic matter (DOM). This study focuses on solution chemistry effects on DOM adsorption/desorption processes by single-walled CNTs (SWCNTs). Our data show that DOM adsorption is controlled by the attachment of DOM molecules to the SWCNTs, and that the initial adsorption rate is dependent on solution parameters. Adsorbed amount of DOM at high ionic strength was limited, possibly due to alterations in SWCNT bundling. Desorption of DOM performed at low pH resulted in additional DOM adsorption, whereas at high pH, adsorbed DOM amount decreased. The extent of desorption conducted at increased ionic strength was dependent on pre-adsorbed DOM concentration: low DOM loading stimulated additional adsorption of DOM, whereas high DOM loading facilitated release of adsorbed DOM. Elevated ionic strength and increased adsorbed amount of DOM reduced the oxidation temperature of the SWCNTs, suggesting that changes in the assembly of the SWCNTs had occurred. Moreover, DOM-coated SWCNTs at increased ionic strength provided fewer sites for atrazine adsorption. This study enhances our understanding of DOM-SWCNT interactions in aqueous systems influenced by rapid changes in salinity, and facilitates potential use of SWCNTs in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Adsorption of Nickel Ion by Low Cost Carbon-Kinetic, Thermodynamic and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    V. Vijayakumaran

    2009-01-01

    Full Text Available A carbonaceous adsorbent prepared from an indigenous waste, by acid treatment was tested for its efficiency in removing nickel ion. The process parameters studied include agitation time, initial metal ion concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm obtained from the Langmuir isotherm plot were found to around 43 mg/g at an initial pH of 7.0. The temperature variation study showed that the nickel ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the nickel ion solutions. The Langmuir and Freundlich adsorption isotherms obtained, positive ΔH0 value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of nickel ion on MCC involves chemisorption as well as physisorption mechanism.

  17. Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Hermida, M. I. [Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, Campus Río San Pedro s/n, 11510 Puerto Real (Spain); Departamento de Física Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Romero-Enrique, J. M. [Departamento de Física Atómica, Molecular y Nuclear, Área de Física Teórica, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Morales-Flórez, V.; Esquivias, L. [Departamento de Física Condensada, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Instituto de Ciencia de Materiales de Sevilla (CSIC/US), Av. Américo Vespucio 49, 41092 Sevilla (Spain)

    2016-08-21

    Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N{sub 2}, CO{sub 2}, and O{sub 2}, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO{sub 2} adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO{sub 2} adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO{sub 2} adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO{sub 2} adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO{sub 2} concentrations and low temperatures, the CO{sub 2} adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

  18. Carbon molecular sieve gas separation membranes based on an intrinsically microporous polyimide precursor

    KAUST Repository

    Ma, Xiaohua

    2013-10-01

    We report the physical characteristics and gas transport properties for a series of pyrolyzed membranes derived from an intrinsically microporous polyimide containing spiro-centers (PIM-6FDA-OH) by step-wise heat treatment to 440, 530, 600, 630 and 800 C, respectively. At 440 C, the PIM-6FDA-OH was converted to a polybenzoxazole and exhibited a 3-fold increase in CO2 permeability (from 251 to 683 Barrer) with a 50% reduction in selectivity over CH4 (from 28 to 14). At 530 C, a distinct intermediate amorphous carbon structure with superior gas separation properties was formed. A 56% increase in CO2-probed surface area accompanied a 16-fold increase in CO2 permeability (4110 Barrer) over the pristine polymer. The graphitic carbon membrane, obtained by heat treatment at 600 C, exhibited excellent gas separation properties, including a remarkable CO2 permeability of 5040 Barrer with a high selectivity over CH4 of 38. Above 600 C, the strong emergence of ultramicroporosity (<7 Å) as evidenced by WAXD and CO2 adsorption studies elicits a prominent molecular sieving effect, yielding gas separation performance well above the permeability-selectivity trade-off curves of polymeric membranes. © 2013 Elsevier Ltd. All rights reserved.

  19. Adsorption of microcystin-LR on mesoporous carbons and its potential use in drinking water source.

    Science.gov (United States)

    Park, Jeong-Ann; Jung, Sung-Mok; Yi, In-Geol; Choi, Jae-Woo; Kim, Song-Bae; Lee, Sang-Hyup

    2017-06-01

    Microcystin-LR (MC-LR) is a common toxin derived from cyanobacterial blooms an effective, rapid and non-toxic method needs to be developed for its removal from drinking water treatment plants (DWTP). For an adsorption-based method, mesoporous carbon can be a promising supplemental adsorbent. The effect of mesoporous carbon (MC1, MC2, and MC3) properties and water quality parameters on the adsorption of MC-LR were investigated and the results were analyzed by kinetic, isotherm, thermodynamic, Derjaguin-Landau-Verwey-Overbeek (DLVO), and intraparticle diffusion models. MC1 was the most appropriate type for the removal of MC-LR with a maximum adsorption capacity of 35,670.49 μg/g. Adsorption of MC-LR is a spontaneous reaction dominated by van der Waals interactions. Pore sizes of 8.5-14 nm enhance the pore diffusion of MC-LR from the surface to the mesopores of MC1. The adsorption capacity was not sensitive to changes in the pH (3.2-8.0) and the existence of organic matter (2-5 mg/L). Furthermore, the final concentration of MC-LR was below the WHO guideline level after a 10-min reaction with 20 mg/L of MC1 in the Nak-Dong River, a drinking water source. The MC-LR adsorption mainly competed with humic substances (500-1000 g/mole); however, they did not have a great effect on adsorption. Copyright © 2017. Published by Elsevier Ltd.

  20. Adsorption of ibuprofen from aqueous solution on chemically surface-modified activated carbon cloths

    Directory of Open Access Journals (Sweden)

    Hanen Guedidi

    2017-05-01

    Full Text Available This study aims to investigate the performance of an activated carbon cloth for adsorption of ibuprofen. The cloth was oxidized by a NaOCl solution (0.13 mol L−1 or thermally treated under N2 (700 °C for 1 hour. The raw and modified cloths were characterized by N2 adsorption–desorption measurement at 77 K, CO2 adsorption at 273 K, Boehm titrations, pHPZC measurements, X-ray Photoelectron Spectroscopy analysis, and by infrared spectroscopy. The NaOCl treatment increases the acidic sites, mostly creating phenolic and carboxylic groups and decreases both the specific surface area and slightly the micropore volume. However, the thermal treatment at 700 °C under N2 induced a slight increase in the BET specific surface area and yielded to the only increase in the carbonyl group content. Ibuprofen adsorption studies of kinetics and isotherms were carried out at pH = 3 and 7. The adsorption properties were correlated to the cloth porous textures, surface chemistry and pH conditions. The isotherms of adsorption were better reproduced by Langmuir–Freundlich models at 298, 313 and 328 K. The adsorption of ibuprofen on the studied activated carbon cloths at pH 3 was an endothermic process. The pore size distributions of all studied ibuprofen-loaded fabrics were determined by DFT method to investigate the accessible porosity of the adsorbate. Both treatments do not influence the kind of micropores where the adsorption of ibuprofen occurred.

  1. Adsorption and Desorption of Dinitrotoluene on Activated Carbon

    National Research Council Canada - National Science Library

    Ho, Patience C; Daw, C. S

    1987-01-01

    .... Both carbons proved to be excel lent adsorbents +or aqueous DNT. The solvents tested +or extracting the adsorbed DNT were water, acetone, and methanol, both individually and in mixtures with each...

  2. Chemical Safety Alert: Fire Hazard from Carbon Adsorption Deodorizing Systems

    Science.gov (United States)

    Activated carbon systems used to adsorb vapors for odor control may pose a fire hazard when used for certain types of substances, such as crude sulfate turpentine. Facilities should take precautions and proper procedures to avoid or mitigate these hazards.

  3. Adsorption of superparamagnetic iron oxide nanoparticles on silica and calcium carbonate sand.

    Science.gov (United States)

    Park, Yoonjee C; Paulsen, Jeffrey; Nap, Rikkert J; Whitaker, Ragnhild D; Mathiyazhagan, Vidhya; Song, Yi-Qiao; Hürlimann, Martin; Szleifer, Igal; Wong, Joyce Y

    2014-01-28

    Superparamagnetic iron oxide (SPIO) nanoparticles have the potential to be used in the characterization of porous rock formations in oil fields as a contrast agent for NMR logging because they are small enough to traverse through nanopores and enhance contrast by shortening NMR T2 relaxation time. However, successful development and application require detailed knowledge of particle stability and mobility in reservoir rocks. Because nanoparticle adsorption to sand (SiO2) and rock (often CaCO3) affects their mobility, we investigated the thermodynamic equilibrium adsorption behavior of citric acid-coated SPIO nanoparticles (CA SPIO NPs) and poly(ethylene glycol)-grafted SPIO nanoparticles (PEG SPIO NPs) on SiO2 (silica) and CaCO3 (calcium carbonate). Adsorption behavior was determined at various pH and salt conditions via chemical analysis and NMR, and the results were compared with molecular theory predictions. Most of the NPs were recovered from silica, whereas far fewer NPs were recovered from calcium carbonate because of differences in the mineral surface properties. NP adsorption increased with increasing salt concentration: this trend was qualitatively explained by molecular theory, as was the role of the PEG grafting in preventing NPs adsorption. Quantitative disagreement between the theoretical predictions and the data was due to NP aggregation, especially at high salt concentration and in the presence of calcium carbonate. Upon aggregation, NP concentrations as determined by NMR T2 were initially overestimated and subsequently corrected using the relaxation rate 1/T2, which is a function of aggregate size and fractal dimension of the aggregate. Our experimental validation of the theoretical predictions of NP adsorption to minerals in the absence of aggregation at various pH and salt conditions demonstrates that molecular theory can be used to determine interactions between NPs and relevant reservoir surfaces. Importantly, this integrated experimental and

  4. Adsorption and performance of the 2-mercaptobenzimidazole as a carbon steel corrosion inhibitor in EDTA solutions

    Energy Technology Data Exchange (ETDEWEB)

    Calderón, J.A., E-mail: andres.calderon@udea.edu.co [Centro de Investigación, Innovación y Desarrollo de Materiales –CIDEMAT, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Vásquez, F.A. [Centro de Investigación, Innovación y Desarrollo de Materiales –CIDEMAT, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Carreño, J.A. [Laboratório de H2S, CO2 e Corrosividade, Instituto Nacional De Tecnologia (INT), Av. Venezuela, 82 – Térreo, Anexo 01, Sala 101A, Saúde, Rio de Janeiro, RJ (Brazil)

    2017-01-01

    This study presents a thermodynamic analysis of the adsorption and anti-corrosion performance of 2-mercaptobenzimidazole (2-MBI) on carbon steel in EDTA-Na2 solutions. The adsorption of the inhibitor on the metal surface was studied as a function of the concentration of the inhibiting species and the temperature of the system. The corrosion inhibition efficiency was studied by electrochemical impedance spectroscopy and mass loss tests. The results show that the adsorption of the inhibitor onto the metal surface behaves according to the Langmuir model, following an endothermic process. The inhibitor is chemically adsorbed onto the carbon steel surface. The efficiency of corrosion inhibition was above 93%, which was confirmed by both mass loss tests and the electrochemical impedance technique. The good performance of the corrosion inhibitor was maintained up to 24 h after the inhibitor was added to the corrosive EDTA-Na2 solutions. When the ratio of the volume of solution/exposed area was reduced, a decrease in the area covered by the inhibitor was observed. The best cost/benefit ratio for the corrosion protection of carbon steel was obtained when the number of moles of the inhibitor per surface area was maintained at 2.68 mmol cm{sup −2}. - Highlights: • Adsorption of the inhibitor on the metal surface is confirmed by thermodynamic data. • Adsorption of the inhibitor onto the metal behaves according to the Langmuir model. • Endothermic adsorption process indicates that the inhibitor is chemically adsorbed. • The efficiency of corrosion inhibition was above 93%. • The good performance of the corrosion inhibitor was maintained up to 24 h.

  5. Carbon Dioxide Absorption in a Membrane Contactor with Color Change

    Science.gov (United States)

    Pantaleao, Ines; Portugal, Ana F.; Mendes, Adelio; Gabriel, Joaquim

    2010-01-01

    A pedagogical experiment is described to examine the physical absorption of gases, in this case carbon dioxide, in a hollow fiber membrane contactor (HFMC) where the absorption concentration profile can be followed by a color change. The HFMC is used to teach important concepts and can be used in interesting applications for students, such as…

  6. Carbon molecular sieve membranes prepared from porous fiber precursor

    NARCIS (Netherlands)

    Barsema, J.N.; van der Vegt, N.F.A.; Koops, G.H.; Wessling, Matthias

    2002-01-01

    Carbon molecular sieve (CMS) membranes are usually prepared from dense polymeric precursors that already show intrinsic gas separation properties. The rationale behind this approach is that the occurrence of any kind of initial porosity will deteriorate the final CMS performance. We will show that

  7. Polyamide membranes modified by carbon nanotubes: Application for pervaporation

    Czech Academy of Sciences Publication Activity Database

    Penkova, A. V.; Polotskaya, G. A.; Gavrilova, V. A.; Toikka, A. M.; Liu, J. C.; Trchová, Miroslava; Šlouf, Miroslav; Pientka, Zbyněk

    2010-01-01

    Roč. 45, č. 1 (2010), s. 35-41 ISSN 0149-6395 Institutional research plan: CEZ:AV0Z40500505 Keywords : carbon nanotubes * dense membranes * pervaporation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.015, year: 2010

  8. Sulfonated carbon black-based composite membranes for fuel cell ...

    Indian Academy of Sciences (India)

    Sci., Vol. 36, No. 4, August 2013, pp. 563–573. c Indian Academy of Sciences. Sulfonated carbon black-based composite membranes for fuel cell applications .... All data were collected from a second heating cycle and glass tran- sition temperatures (Tg) were calculated as a midpoint of thermogram. 2.5d FTIR studies: FTIR ...

  9. Supercapacitive bioelectrochemical solar cells using thylakoid membranes and carbon nanotubes

    DEFF Research Database (Denmark)

    Pankratov, Dmitrii; Pankratova, G.; Åkerlund, H.-E.

    and storage in the form of electric charge within a singular contrivance, we have developed and investigated supercapacitive photo-bioanodes based on the carboxilized and amidized multiwalled carbon nanotubes (MWСNTs) in direct electron transfer (DET) communication with adsorbed thylakoid membranes...

  10. Sulfonated carbon black-based composite membranes for fuel cell ...

    Indian Academy of Sciences (India)

    C/min under nitrogen atmosphere. All data were collected from a second heating cycle and glass tran- sition temperatures (Tg) were calculated as a midpoint of thermogram. 2.5d FTIR studies: FTIR spectra were recorded for mem- branes using Perkin Elmer Pyris 1 FTIR spectrophoto- meter. Membrane and carbon black ...

  11. Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation.

    Science.gov (United States)

    Altenor, Sandro; Carene, Betty; Emmanuel, Evens; Lambert, Jacques; Ehrhardt, Jean-Jacques; Gaspard, Sarra

    2009-06-15

    Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, X(P) (gH(3)PO(4)/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m(2)/g) and high pore volume (up to 1.19 cm(3)/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (R(2)) and the normalized standard deviation Deltaq (%) were determined showing globally, that the recently derived fractal kinetic equation could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich-Peterson equations, but as well the newly published deformed Weibull Brouers-Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers-Sotolongo equation and with the Redlich-Peterson equation. Influence of surface functional groups towards MB adsorption is as well studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB

  12. Carbon Nano tubes Based Mixed Matrix Membrane for Gas Separation

    International Nuclear Information System (INIS)

    Sanip, S.M.; Ismail, A.F.; Goh, P.S.; Norrdin, M.N.A.; Soga, T.; Tanemura, M.; Yasuhiko, H.

    2011-01-01

    Carbon nano tubes based mixed matrix membrane (MMM) was prepared by the solution casting method in which the functionalized multi walled carbon nano tubes (f-MWNTs) were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0 wt % on the gas separation properties were looked into. The morphologies of the MMM also indicated that at 0.7 % loading of f- MWNTs, the structures of the MMM showed uniform finger-like structures which have facilitated the fast gas transport through the polymer matrix. It may also be concluded that addition of open ended and shortened MWNTs to the polymer matrix can improve its permeability by increasing diffusivity through the MWNTs smooth cavity. (author)

  13. Hydrogen Adsorption Properties of Carbon Nanotubes and Platinum Nanoparticles from a New Ammonium-Ethylimidazolium Chloroplatinate Salt.

    Science.gov (United States)

    Tamburri, Emanuela; Cassani, Maria Cristina; Ballarin, Barbara; Tomellini, Massimo; Femoni, Cristina; Mignani, Adriana; Terranova, Maria Letizia; Orlanducci, Silvia

    2016-05-23

    Self-supporting membranes built entirely of carbon nanotubes have been prepared by wet methods and characterized by Raman spectroscopy. The membranes are used as supports for the electrodeposition of Pt nanoparticles without the use of additional additives and/or stabilizers. The Pt precursor is an ad hoc synthesized ammonium-ethylimidazolium chloroplatinate(IV) salt, [NH3 (CH2 )2 MIM)][PtCl6 ]. The Pt complex was characterized using NMR spectroscopy, XRD, ESI-MS, and FTIR spectroscopy. The interaction between the Pt-carbon nanotubes nanocomposites and hydrogen is analyzed using electrochemical and quartz microbalance measurements under near-ambient conditions. The contribution of the Pt phase to the hydrogen adsorption on nanotube is found and explained by a kinetic model that takes into account a spillover event. Such a phenomenon may be exploited conveniently for catalysis and electrocatalysis applications in which the hybrid systems could act as a hydrogen transfer agent in specific hydrogenation reactions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Adsorption Efficiency of Iron Modified Carbons for Removal of Pb(II Ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Salmani

    2016-06-01

    Full Text Available Abstract Introduction: The Lead causes severe damage to several systems of the body, especially to bony tissues. Until now, several low-cost biosorbents have been studied for removal of heavy metal ions from aqueous solutions. In the present study, carbonized pomegranate peels modified with Fe2+ and Fe3+ ions and then it was investigated for removal of Pb(II ions from aqueous solution. Materials and methods: the washed granola of pomegranate peel was separately socked with FeCl3 and FeCl2 solutions for 24 h. Then, the granules were carbonized at 400 ºC for 3 h in a programmable furnace in the atmosphere of nitrogen. The adsorption experiments were carried out for two types of iron-modified carbons by batch adsorption using one variable at a time procedures. Results: The optimum conditions were found as contact time 90 min, initial concentration 50 mg/l, and adsorbent dose, 1.00 g/100 ml solution. Maximum removal efficiency was calculated as 84% and 89% for Fe3+ and Fe2+ impregnated pomegranate peel carbons respectively. Conclusion: The iron treatment pomegranate peel carbons modified their surfaces for adsorption of heavy metals. The results showed that chemical modification of the low-cost adsorbents originating from agricultural waste has stood out for metal removal capabilities.

  15. Carbonate adsorption onto goethite as a function of pH and ionic strength

    International Nuclear Information System (INIS)

    Rundberg, R.S.; Albinsson, Y.

    1991-01-01

    The adsorption of carbonate onto geothite was studied as a function of both pH and ionic strength (NaClO 4 electrolyte) using 14 C tracer. The pH ranged from 2.5 to 11.6. The ionic strength was controlled by varying the NaClO 4 concentration and ranged from 0.01 to 0.1 molar. The results indicate that carbonate is adsorbed on goethite as primarily an inner-sphere complex at pH values above the point of zero charge. This is inferred from the lack of dependence on ionic strength in the adsorption of carbonate. Below the point of zero charge carbonate is adsorbed by an additional outer-sphere mechanism. An adsorption isotherm was measured at pH 7.0 with an electrolyte concentration of 0.01M. Deconvolution of the isotherm proved that at least two sorption mechanisms exist. These mechanisms lead to large distribution coefficients at low pH. Thereby making the complete removal and exclusion of carbonate from an aqueous goethite system difficult, for the purpose of characterizing a ''clean'' goethite surface

  16. Adsorption and manipulation of carbon onions on highly oriented pyrolytic graphite studied with atomic force microscopy

    International Nuclear Information System (INIS)

    Zhou Jianfeng; Shen Ziyong; Hou Shimin; Zhao Xingyu; Xue Zengquan; Shi Zujin; Gu Zhennan

    2007-01-01

    Carbon onions produced by DC arc discharge method were deposited on highly oriented pyrolytic graphite (HOPG) surface and their adsorption and manipulation was studied using an atomic force microscopy (AFM). Well-dispersed adsorption of carbon onions on HOPG surface was obtained and aggregations of onions were not observed. The van der Waals interaction between the onion and HOPG surface and that between two onions, were calculated and discussed using Hamaker's theory. The manipulation of adsorbed onions on HOPG surface was realized using the AFM in both the raster mode and the vector mode. The controllability and precision of two manipulation modes were compared and the vector mode manipulation was found superior, and is a useful technique for the construction of nano-scale devices based on carbon onions

  17. Bicarbonate adsorption band of the chromatography for carbon isotope separation using anion exchangers

    International Nuclear Information System (INIS)

    Takeda, Kunihiko; Obanawa, Heiichiro; Hata, Masahisa; Sato, Katsuya

    1985-01-01

    The equilibria of bicarbonate ion between two phases were studied for the carbon isotope separation using anion exchangers. The condition of the formation of a bicarbonate adsorption band was quantitatively discussed. The formation of the adsorption band depends on the difference of S-potential which is the sum of the standard redection chemical potentials and L-potential which is the sum of the reduction chemical potential. The isotopic separation factor observed was about 1.012, independent of the concentrations of acid and alkali in the solutions. The isotopic separation factor was considered to be determined by the reaction of bicarbonate ion on anion exchangers and carbon dioxide dissolved in solutions. The enriched carbon isotope whose isotopic abundance ratio ( 13 C/ 12 C) was 1.258 was obtained with the column packed with anion exchangers. (author)

  18. Nanostructured carbon materials for adsorption of methane and other gases

    Science.gov (United States)

    Stadie, Nicholas P.; Fultz, Brent T.; Ahn, Channing; Murialdo, Maxwell

    2015-06-30

    Provided are methods for storing gases on porous adsorbents, methods for optimizing the storage of gases on porous adsorbents, methods of making porous adsorbents, and methods of gas storage of optimized compositions, as in systems containing porous adsorbents and gas adsorbed on the surface of the porous adsorbent. The disclosed methods and systems feature a constant or increasing isosteric enthalpy of adsorption as a function of uptake of the gas onto the exposed surface of a porous adsorbent. Adsorbents with a porous geometry and surface dimensions suited to a particular adsorbate are exposed to the gas at elevated pressures in the specific regime where n/V (density) is larger than predicted by the ideal gas law by more than several percent.

  19. DFT calculation for adatom adsorption on graphene sheet as a prototype of carbon nanotube functionalization

    International Nuclear Information System (INIS)

    Ishii, A; Yamamoto, M; Asano, H; Fujiwara, K

    2008-01-01

    DFT calculation of various atomic species on graphene sheet is investigated as prototypes for formation of nano-structures on carbon nanotube (CNT) wall. We investigate computationally adsorption energies and adsorption sites on graphene sheet for a lot of atomic species including transition metals, noble metals, nitrogen and oxygen, using the DFT calculation as a prototype for CNT. The suitable atomic species can be chosen as each application from those results. The calculated results show us that Mo and Ru are bounded strongly on graphene sheet with large diffusion barrier energy. On the other hand, some atomic species has large binding energies with small diffusion barrier energies

  20. FTIR study of carbon monoxide adsorption on ion-exchanged X, Y and mordenite type zeolites

    Directory of Open Access Journals (Sweden)

    R. HERCIGONJA

    2003-05-01

    Full Text Available In this work Fourier transform infrared (FTIR study has been applied to study the adsorption of carbon monoxide on transition metal (Mn+, Co2+, Ni2+ ion-exchanged zeolites type Y, X and mordenites. The adsorption of CO at room temperature produces overlapping IR absorption bands in the 2120–2200 cm-1 region. The frequency of the band around 2200 cm-1 is found to be dependent not only on the charge-balancing transition metal cation, but also on the framework composition. The frequencies of the band near 1600 cm-1 was found to be dependent on the Si/Al ratio of the investigated zeolites.

  1. Nitrogen Adsorption on Graphene Sponges Synthesized by Annealing a Mixture of Nickel and Carbon Powders

    Directory of Open Access Journals (Sweden)

    Grehov V.

    2017-08-01

    Full Text Available Adsorption by graphene sponge (GS manufactured by annealing nickel-carbon powder mixture in inert atmosphere has been studied. By determining the specific surface area (SSA for the GS sample, it has been found that Brunauer, Emmett, Teller method (BET of approximation of experimental isotherms gives wrong results in the pressure range of 0.025–0.12 because adsorption in this pressure region is affected by walls of ampoule. Real SSA value has been found by subtracting pore effect method (SPE or by BET approximation in a low range of relative pressure of 0.0004–0.002.

  2. Adsorption of Phosphonate Antiscalant from Reverse Osmosis Membrane Concentrate onto Granular Ferric Hydroxide

    NARCIS (Netherlands)

    Boels, L.; Keesman, K.J.; Witkamp, G.J.

    2012-01-01

    Adsorptive removal of antiscalants offers a promising way to improve current reverse osmosis (RO) concentrate treatment processes and enables the reuse of the antiscalant in the RO desalination process. This work investigates the adsorption and desorption of the phosphonate antiscalant

  3. Adsorption Isotherm of Chromium (Vi) into Zncl2 Impregnated Activated Carbon Derived by Jatropha Curcas Seed Hull

    Science.gov (United States)

    Mohammad, M.; Yakub, I.; Yaakob, Z.; Asim, N.; Sopian, K.

    2017-12-01

    Hexavalent chromium is carcinogenic and should be removed from industrial wastewater before discharged into water resources. Adsorption by using activated carbon from biomass is an economic and conventional way on removing the heavy metal ions from wastewater. In this research, activated carbon is synthesized from Jatropha curcas L. seed hull through chemical activation with ZnCl2 and carbonized at 800 °C (JAC/ZnCl2). The activated carbon has been characterized using FTIR, SEM-EDX, BET and CHNS-O analyzer. Adsorption isotherms have been analysed using Langmuir and Freundlich models to determine its removal mechanism. The maximum adsorption capacity of Cr (VI) metal ions onto JAC/ZnCl2 activated carbon is 25.189 mg/g and following Langmuir isotherm model which is monolayer adsorption.

  4. Adsorption efficiency of coconut shell-based activated carbons on ...

    African Journals Online (AJOL)

    A colour comparator was used to determine the colour of the molassess, volumetric analysis was used to determine oxygen and related parameters while oil and grease were determined by gravimetry. The results showed that the activated carbons used in this study are capable of reducing the level of colour present in ...

  5. Evaluation of dum palm kernel activated carbon in chromium and lead adsorption from synthetic waste water

    Directory of Open Access Journals (Sweden)

    HI Mohammed

    2016-09-01

    Full Text Available This study aimed at the co-current removal of chromium and lead ions from synthetic waste water using dum palm kernel activated carbon. The adsorption experiment was conducted by varying time, pH and concentrations of the simulated solution. The data obtained were analyzed, and the best conditions for the uptake were at pH of 6, equilibrium time of 40 minutes. The two best isotherms models for the adsorption system were Sip, and Dubinin–Radushkevich, models respectively. Based on the Temkin adsorption energy calculated as 9.5793 and 0.4997 J/mol, the uptake of lead and chromium were chemisorption and physico-sorption, respectively. The maximum uptake calculated from Dubinin–Radushkevich plots were 14.1696 and 7.7191 mg/g, for lead and chromium, respectively.International Journal of Environment Vol.5(3 2016, pp.104-118

  6. Preparation and Adsorption Performances of Phragmites australis Activated Carbon with High Acidity

    Directory of Open Access Journals (Sweden)

    FU Cheng-kai

    2017-03-01

    Full Text Available For removal of heavy metals from wastewater and recycling the wetland plants, the present study investigated the viability of using silage of Phragmites australis (PA to prepare activated carbons (ACs with high acidity. BET surface area, porous texture and surface functional characteristics of ACs were analyzed by N2 adsorption/desorption, elemental analysis and Boehm titration method. ACs presented well-developed micro-porosity and favorable surface acidity. The sorption equilibrium data for Ni (Ⅱ and Cd (Ⅱ sorption onto ACs were analyzed by the Langmuir and Freundlich models. The Langmuir model was fitted well to the adsorption behavior. The properties of high surface acidity promoted the adsorption of heavy metals by the silage-treated ACs and the chemical sorption played the key role in the sorption process.

  7. CO2 adsorption on single-walled dahlia-like carbon nanohorns

    Science.gov (United States)

    Bohorquez, Jaime; Krungleviciute, Vaiva; Migone, Aldo; Yudasaka, Masako; Iijima, Sumio

    2010-03-01

    The adsorption of CO2 on spherical aggregates of as-produced (i.e., closed) dahlia-like single-walled carbon nanohorns was investigated. We conducted volumetric adsorption measurements at five temperatures between 147 and 180 K. The shape of the isotherms for CO2 is very different from those measured with neon and CF4. For CO2 there is a single, smeared step in the adsorption data between the lowest coverages and saturation. By contrast, Ne and CF4 show two distinct substeps on the same substrate. The isosteric heat was also obtained and its dependence on coverage also showed an usual behavior: it increased with increasing coverage. The isosteric heat decreases with coverage both for Ne and CF4. The stronger intermolecular interactions present for CO2 probably are responsible for this adsorbate's unusual behavior. Comparisons with the behavior reported in the literature for CO2 on SWNTs, which shows similar unusual characteristics, will also be made.

  8. External capillary condensation and adsorption of VOCs onto activated carbon fiber cloth and felt.

    Science.gov (United States)

    Fournel, L; Mocho, P; Fanlo, J L; Le Cloirec, P

    2005-11-01

    Adsorption isotherms of some volatile organic compounds (VOCs), present in air at concentrations ranging from 10 to 2500 mg m(-3), were performed onto activated carbon fiber cloth and felt. The VOCs loading air were isopropanol, toluene, acetone, methyl ethyl ketone, ethyl acetate and dichloromethane. Isotherm adsorption data were generated. These experimental values were modeled by the equation of Dubinin and co-workers and by the Langmuir relation. Model parameters are discussed as a function of adsorbent materials and VOC structure. Adsorption capacity was generally found higher for the cloth than for the felt. An effect of external capillary condensation onto the felt of compounds with high surface tension was demonstrated for VOC concentrations above 1500 mg m(-3).

  9. Density function theory study of the adsorption and dissociation of carbon monoxide on tungsten nanoparticles.

    Science.gov (United States)

    Weng, Meng-Hsiung; Ju, Shin-Pon; Chen, Hsin-Tsung; Chen, Hui-Lung; Lu, Jian-Ming; Lin, Ken-Huang; Lin, Jenn-Sen; Hsieh, Jin-Yuan; Yang, Hsi-Wen

    2013-02-01

    The adsorption and dissociation properties of carbon monoxide (CO) molecule on tungsten W(n) (n = 10-15) nanoparticles have been investigated by density-functional theory (DFT) calculations. The lowest-energy structures for W(n) (n = 10-15) nanoparticles are found by the basin-hopping method and big-bang method with the modified tight-binding many-body potential. We calculated the corresponding adsorption energies, C-O bond lengths and dissociation barriers for adsorption of CO on nanoparticles. The electronic properties of CO on nanoparticles are studied by the analysis of density of state and charge density. The characteristic of CO on W(n) nanoparticles are also compared with that of W bulk.

  10. Removal of methylene blue by adsorption onto activated carbon developed from Ficus carica bast

    Directory of Open Access Journals (Sweden)

    Deepak Pathania

    2017-02-01

    Full Text Available In this study, activated carbon was developed from Ficus carica bast (FCBAC. The experiments were carried out to explore methylene blue (MB uptake by FCBAC. The influence of various experimental factors such as contact time, initial dye concentration, adsorbent dosage, temperature and pH of dye solution was investigated. The adsorption equilibrium was represented with Langmuir, Freundlich and Temkin isotherm models. Langmuir and Tempkin equations were found to have the correlation coefficient value in good agreement. Adsorption of MB onto FCBAC followed pseudo second order kinetics. The calculated values of ΔH°, ΔS° and ΔG° were found to be 21.55 kJ/mol, 76.24 J/mol K and −1.55 kJ/mol, respectably. Adsorption process was spontaneous and endothermic in nature.

  11. Preparation of PVA/amino multi-walled carbon nanotubes nanocomposite microspheres for endotoxin adsorption.

    Science.gov (United States)

    Zong, Wenhui; Chen, Jian; Han, Wenyan; Cheng, Guanghui; Chen, Jie; Wang, Yue; Wang, Weichao; Ou, Lailiang; Yu, Yaoting; Shen, Jie

    2018-02-01

    A novel polyvinyl alcohol-amino multi-walled carbon nanotube (PVA-AMWCNT) nanocomposite microsphere was prepared successfully for the first time and used for endotoxin removal. The resulting AMWCNT modified PVA microsphere was characterized by SEM, Raman spectrum and fluorescence image, which indicated AMWCNT was dispersed into the macropores of PVA microsphere uniformly. The PVA-AMWCNT microspheres showed better adsorption capability and faster adsorption equilibrium for endotoxin in aqueous solution when compared to the PVA microsphere with polymyxin B (PMB) as ligand. More noteworthy, the PVA based microspheres had little nonspecific adsorption in simulated serum. Therefore, PVA-AMWCNT nanocomposite microsphere with an excellent haemocompatibility has a great potential application in clinical blood purification.

  12. Experimental Adsorption Isotherm of Methane onto Activated Carbon at Sub- and Supercritical Temperatures

    KAUST Repository

    Rahman, Kazi Afzalur

    2010-11-11

    This paper presents the experimentally measured adsorption isotherm data for methane onto the pitch-based activated carbon type Maxsorb III for temperatures ranging from (120 to 220) K and pressures up to 1.4 MPa. These data are useful to study adsorbed natural gas (ANG) storage systems when the low temperature natural gas regasified from the liquid phase is considered to charge in the storage chamber. Adsorption parameters were evaluated from the isotherm data using the Tóth and Dubinin-Astakhov models. The isosteric heat of adsorption, which is concentration- and temperature-dependent, is extracted from the data. The Henry\\'s law coefficients for the methane/Maxsorb III pairs are evaluated at various temperatures. © 2010 American Chemical Society.

  13. Adsorption behavior of DNA-wrapped carbon nanotubes on self-assembled monolayer surfaces.

    Science.gov (United States)

    Zangmeister, Rebecca A; Maslar, James E; Opdahl, Aric; Tarlov, Michael J

    2007-05-22

    We have examined the adsorption of DNA-wrapped single-walled carbon nanotubes (DNA-SWNTs) on hydrophobic, hydrophilic, and charged surfaces of alkylthiol self-assembled monolayers (SAMs) on gold. Our goal is to understand how DNA-SWNTs interact with surfaces of varying chemical functionality. These samples were characterized using reflection absorption FTIR (RAIRS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. We have found that DNA-SWNTs preferentially adsorb to positively charged amine-terminated SAMs and to bare gold surfaces versus hydrophobic methyl-terminated or negatively charged carboxylic acid-terminated SAMs. Examination of the adsorption on gold of single-strand DNA (ssDNA) of the same sequence used to wrap the SWNTs suggests that the DNA wrapping plays a role in the adsorption behavior of DNA-SWNTs.

  14. Adsorption of aqueous metal ions on cattle-manure-compost based activated carbons.

    Science.gov (United States)

    Zaini, Muhammad Abbas Ahmad; Okayama, Reiko; Machida, Motoi

    2009-10-30

    The objective of this study is to examine the suitability and performance of cattle-manure-compost (CMC) based activated carbons in removing heavy metal ions from aqueous solution. The influence of ZnCl(2) activation ratios and solution pH on the removal of Cu(II) and Pb(II) were studied. Pore texture, available surface functional groups, pH of point zero charge (pH(PZC)), thermogravimetric analysis and elemental compositions were obtained to characterize the activated carbons. Batch adsorption technique was used to determine the metal-binding ability of activated carbons. The equilibrium data were characterized using Langmuir, Freundlich and Redlich-Peterson models. It was found that the uptake of aqueous metal ions by activated carbons could be well described by Langmuir equation. It is suggested that the increase of surface area and mesopore ratio as a result of increasing activation ratios favored the removal of Cu(II), while activated carbon rich in acidic groups showed selective adsorption towards Pb(II). The preferable removal of Cu(II) over Pb(II) could be due to the rich nitrogen content as well as the higher mesoporous surface area in the CMC activated carbons. The impregnated CMC activated carbons also showed a better performance for Cu(II) removal at varying solution pH than Filtrasorb 400 (F400), while a similar performance was observed for Pb(II) removal.

  15. Ammonia removal in the carbon contactor of a hybrid membrane process.

    Science.gov (United States)

    Stoquart, Céline; Servais, Pierre; Barbeau, Benoit

    2014-12-15

    The hybrid membrane process (HMP) coupling powdered activated carbon (PAC) and low-pressure membrane filtration is emerging as a promising new option to remove dissolved contaminants from drinking water. Yet, defining optimal HMP operating conditions has not been confirmed. In this study, ammonia removal occurring in the PAC contactor of an HMP was simulated at lab-scale. Kinetics were monitored using three PAC concentrations (1-5-10 g L(-1)), three PAC ages (0-10-60 days), two temperatures (7-22 °C), in ambient influent condition (100 μg N-NH4 L(-1)) as well as with a simulated peak pollution scenario (1000 μg N-NH4L(-1)). The following conclusions were drawn: i) Using a colonized PAC in the HMP is essential to reach complete ammonia removal, ii) an older PAC offers a higher resilience to temperature decrease as well as lower operating costs; ii) PAC concentration inside the HMP reactor is not a key operating parameter as under the conditions tested, PAC colonization was not limited by the available surface; iii) ammonia flux limited biomass growth and iv) hydraulic retention time was a critical parameter. In the case of a peak pollution, the process was most probably phosphate-limited but a mixed adsorption/nitrification still allowed reaching a 50% ammonia removal. Finally, a kinetic model based on these experiments is proposed to predict ammonia removal occurring in the PAC reactor of the HMP. The model determines the relative importance of the adsorption and biological oxidation of ammonia on colonized PAC, and demonstrates the combined role of nitrification and residual adsorption capacity of colonized PAC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Potassium Tethered Carbons with Unparalleled Adsorption Capacity and Selectivity for Low-Cost Carbon Dioxide Capture from Flue Gas.

    Science.gov (United States)

    Zhao, Hongyu; Shi, Lei; Zhang, Zhongzheng; Luo, Xiaona; Zhang, Lina; Shen, Qun; Li, Shenggang; Zhang, Haijiao; Sun, Nannan; Wei, Wei; Sun, Yuhan

    2018-01-31

    Carbons are considered less favorable for postcombustion CO 2 capture because of their low affinity toward CO 2 , and nitrogen doping was widely studied to enhance CO 2 adsorption, but the results are still unsatisfactory. Herein, we report a simple, scalable, and controllable strategy of tethering potassium to a carbon matrix, which can enhance carbon-CO 2 interaction effectively, and a remarkable working capacity of ca. 4.5 wt % under flue gas conditions was achieved, which is among the highest for carbon-based materials. More interestingly, a high CO 2 /N 2 selectivity of 404 was obtained. Density functional theory calculations evidenced that the introduced potassium carboxylate moieties are responsible for such excellent performances. We also show the effectiveness of this strategy to be universal, and thus, cheaper precursors can be used, holding great promise for low-cost carbon capture from flue gas.

  17. Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation

    Science.gov (United States)

    Ma, Xiaodong; Ouyang, Feng

    2013-03-01

    Activated carbon prepared from spent coffee grounds and pomelo skin by phosphoric acid activation had been employed as the adsorbent for ethylene and n-butane at room temperature. Prepared activated carbon was characterized by means of nitrogen adsorption-desorption, X-ray powder diffraction, scanning electron microscope and Fourier transform infrared spectroscope. It was confirmed that pore structure played an important role during the adsorption testes. Adsorption isotherms of ethylene and n-butane fitted well with Langmuir equation. The prepared samples owned better adsorption capacity for n-butane than commercial activated carbon. Isosteric heats of adsorptions at different coverage were calculated through Clausius-Clapeyron equation. Micropore filling effect was explained in a thermodynamic way.

  18. Factors Affecting the Adsorption of Trivalent Chromium Ions by Activated Carbon Prepared from Waste Rubber Tyres

    Directory of Open Access Journals (Sweden)

    Sylvia E. Benjamin

    2017-08-01

    Full Text Available Economic gains are generally the outcome of industrialization and consequently urbanization. However, positive fiscal index generates a negative impact on natural environment sources heaving pollutant burden on soil, air and water. Industries throw tones of contaminated water into soil and water bodies without proper treatment and create a potential threat for both living and non-living species. Chromium in trivalent state (Cr3+ is added in water bodies and soil through waste water from tanneries, cooling water systems, chemical and pulp and paper industries. The present research work aims at the preparation of an inexpensive activated carbon prepared from non- degradable waste scrap rubber tyres. The carbon produced from scrap rubber tyres was activated by 5% solution of BaCl2 and 0.4 N solution of HCl and verified by ethylene blue solution. The adsorption capacity of the Tyre activated carbon (TAC was investigated for different parameters i.e., initial chromium (III ion concentration, activated carbon dosage, contact/ stirring time and pH. The adsorption capacity of TAC depends on the initial metal ion concentration and the TAC dose. pH of the chromium solution effects the adsorption capacity of TAC due to the formation of tetra hydroxochromate(III complexes,. The results show that TAC offers a cost effective reclamation process for the removal of Cr3+ from effluent waters.

  19. Adsorption/oxidation of sulfur-containing gases on nitrogen-doped activated carbon

    Directory of Open Access Journals (Sweden)

    Liu Qiang

    2016-01-01

    Full Text Available Coconut shell-based activated carbon (CAC was used for the removal of methyl mercaptan (MM. CAC was modified by urea impregnation and calcined at 450°C and 950°C. The desulfurization activity was determined in a fixed bed reactor under room temperature. The results showed that the methyl mercaptan adsorption/oxidation capacity of modified carbon caicined at 950°C is more than 3 times the capacity of original samples. On the other hand, the modified carbon caicined at 950°C also has a high capacity for the simultaneous adsorption/oxidation of methyl mercaptan and hydrogen sulfide.The introduce of basic nitrogen groups siginificantly increases the desulfurization since it can facilitate the electron transfer process between sulfur and oxygen. The structure and chemical properties are characterized using Boehm titration, N2 adsorption-desorption method, thermal analysis and elemental analysis. The results showed that the major oxidation products were dimethyl disulfide and methanesulfonic acid which adsorbed in the activated carbon.

  20. Removal of organic fractions from landfill leachate by casuarina equisetifolia activated carbon: Characteristics and adsorption mechanisms

    Science.gov (United States)

    Alrozi, Rasyidah; Zubir, Nor Aida; Kamaruddin, Mohamad Anuar; Yusof, Siti Noor Faizah Mohd; Yusoff, Mohd Suffian

    2017-09-01

    In this research, the activated carbon prepared from tropical plant waste based Casuarinas Equisetifolia plant was activated through chemical activation by using potassium hydroxide (KOH) as the activating agent. The raw sample was carbonized following conventional heating via electric furnace at 600˚C with the increasing temperature 30˚C/minutes in one hour which was selected as the optimum condition. The prepared activated carbons exhibit mesoporous with the pore diameter within 0.2 µm to 20 µm. From the Scanning Electron Microscopy (SEM) micrographs, the morphology of the activated carbon indicated that they demonstrated high pore development on it surfaces. The effects of initial pH, contact time and adsorbent dosage onto the adsorption performances were evaluated through batch adsorption study. The COD removal increased when the adsorbent dosage was increased. The adsorption of COD and colour were best fitted by the Freundlich isotherm model compared to ammonia, which the correlation regressions, R2 were 0.8451, 0.8315 and 0.6608, respectively. The result of the preliminary of the experimental indicated that the Casuarinas Equisetifolia plant is a promising raw material suitable for turning from waste into wealth.

  1. Photothermal Effects and Applications of Polydimethylsiloxane Membranes with Carbon Nanoparticles

    Directory of Open Access Journals (Sweden)

    Reinher Pimentel-Domínguez

    2016-03-01

    Full Text Available The advent of nanotechnology has triggered novel developments and applications for polymer-based membranes with embedded or coated nanoparticles. As an example, interaction of laser radiation with metallic and carbon nanoparticles has shown to provide optically triggered responses in otherwise transparent media. Incorporation of these materials inside polymers has led to generation of plasmonic and photothermal effects through the enhanced optical absorption of these polymer composites. In this work, we focus on the photothermal effects produced in polydimethylsiloxane (PDMS membranes with embedded carbon nanoparticles via light absorption. Relevant physical parameters of these composites, such as nanoparticle concentration, density, geometry and dimensions, are used to analyze the photothermal features of the membranes. In particular, we analyze the heat generation and conduction in the membranes, showing that different effects can be achieved and controlled depending on the physical and thermal properties of the composite material. Several novel applications of these light responsive membranes are also demonstrated, including low-power laser-assisted micro-patterning and optomechanical deformation. Furthermore, we show that these polymer-nanoparticle composites can also be used as coatings in photonic and microfluidic applications, thereby offering an attractive platform for developing light-activated photonic and optofluidic devices.

  2. Application of modified multiwall carbon nanotubes as a sorbent for zirconium (IV) adsorption from aqueous solution

    International Nuclear Information System (INIS)

    Yavari, R.; Davarkhah, R.

    2013-01-01

    Modified multiwall carbon nanotubes (MWCNTs) by nitric acid solution were used to investigate the adsorption behavior of zirconium from aqueous solution. Pristine and oxidized MWCNTs were characterized using nitrogen adsorption/desorption isotherm, Boehm's titration method, thermogravimetry analysis, transmission electron microscopy and Fourier transform infrared spectroscopy. The results showed that the surface properties of MWCNTs such as specific surface area, total pore volume, functional groups and the total number of acidic and basic sites were improved after oxidation. These improvements are responsible for their hydrophobic properties and consequently an easy dispersion in water and suitable active sites for more adsorption of zirconium. The adsorption of Zr(IV) as a function of initial concentration of zirconium, contact time, MWCNTs dosage, HCl and HNO 3 concentration and also ionic strength was investigated using a batch technique under ambient conditions. The experimental results indicated that sorption of Zr(IV) was strongly influenced by zirconium concentrations, oxidized MWCNTs content and acid pH values. The calculated correlation coefficient of the linear regressions values showed that Langmuir model fits the adsorption equilibrium data better than the Freundlich model. Kinetic data of sorption indicated that equilibrium was achieved within 60 min and the adsorption process can be described by the pseudo second-order reaction rate model. Based on the experimental results, surface complexation is the major mechanism for adsorption of Zr(IV) onto MWCNTs. Also, Study on the desorption process of zirconium showed that the complete recovery can be obtained using nitric or hydrochloric acids of 4 M. (author)

  3. KINETIC AND THERMODYNAMIC STUDY OF THE ADSORPTION OF MANGANESE (II ON ACTIVATED CARBON

    Directory of Open Access Journals (Sweden)

    OUISSAF BENTABET

    2012-06-01

    Full Text Available Recent studies revealed the Bay of Algiers was being polluted by manganese. Similar pollution was also reported in Azemmour, Morocco alongside the estuary of Oum Er Rbia, but also in the waters of developed countries (i.e. Canada, especially following the replacement of tetraethylplumbane in gasoline by methylcyclopentadienyl manganese. Treatment of polluted waters by manganese is therefore essential prior to their release, which is within the purpose of the present study. Commercial activated carbon (AC was used for treating synthetic aqueous solution containing different concentrations of Mn. Adsorption kinetics was studied under agitation at different temperatures between 295 and 318 K. Results show that there are two areas where adsorption occurs according to a first-class model. In the first one, rate constant is k1 = 0.001610 min-1, meanwhile in the second, it is k2 = 0.000488 min-1. Equilibrium is reached in 7 hours. The obtained adsorption isotherm is a V type and follows Freundlich model for low concentrations and Langmuir model for high concentrations. The isotherm part described by Freundlich model lessens with the rise of temperature, increasing adsorption maximum capacity from 3.49 mg Mn/g AC (at 295 K to 4.78 mg Mn/g AC (at 318 K. Adsorption is endothermic. Standard enthalpy (14.4869 kJ•mol-1 and standard entropy (36.25 J•mol-1•K-1 have been calculated. The free energy was positive in all the studied temperatures range. The values of adsorption heat indicate a physical adsorption.

  4. Mechanism of Methylene Blue adsorption on hybrid laponite-multi-walled carbon nanotube particles.

    Science.gov (United States)

    Manilo, Maryna; Lebovka, Nikolai; Barany, Sandor

    2016-04-01

    The kinetics of adsorption and parameters of equilibrium adsorption of Methylene Blue (MB) on hybrid laponite-multi-walled carbon nanotube (NT) particles in aqueous suspensions were determined. The laponite platelets were used in order to facilitate disaggregation of NTs in aqueous suspensions and enhance the adsorption capacity of hybrid particles for MB. Experiments were performed at room temperature (298 K), and the laponite/NT ratio (Xl) was varied in the range of 0-0.5. For elucidation of the mechanism of MB adsorption on hybrid particles, the electrical conductivity of the system as well as the electrokinetic potential of laponite-NT hybrid particles were measured. Three different stages in the kinetics of adsorption of MB on the surface of NTs or hybrid laponite-NT particles were discovered to be a fast initial stage I (adsorption time t=0-10 min), a slower intermediate stage II (up to t=120 min) and a long-lasting final stage III (up to t=24hr). The presence of these stages was explained accounting for different types of interactions between MB and adsorbent particles, as well as for the changes in the structure of aggregates of NT particles and the long-range processes of restructuring of laponite platelets on the surface of NTs. The analysis of experimental data on specific surface area versus the value of Xl evidenced in favor of the model with linear contacts between rigid laponite platelets and NTs. It was also concluded that electrostatic interactions control the first stage of adsorption at low MB concentrations. Copyright © 2015. Published by Elsevier B.V.

  5. Influence of the pore structure and surface chemical properties of activated carbon on the adsorption of mercury from aqueous solutions

    International Nuclear Information System (INIS)

    Lu, Xincheng; Jiang, Jianchun; Sun, Kang; Wang, Jinbiao; Zhang, Yanping

    2014-01-01

    Highlights: • Activated carbons with different pore structure and surface chemical properties were prepared by modification process. • HgCl 2 as a pollution target to evaluate the adsorption performance. • Influence of pore structure and surface chemical properties of activated carbon on adsorption of mercury was investigated. -- Abstract: Reactivation and chemical modification were used to obtain modified activated carbons with different pore structure and surface chemical properties. The samples were characterized by nitrogen absorption–desorption, Fourier transform infrared spectroscopy and the Bothem method. Using mercury chloride as the target pollutant, the Hg 2+ adsorption ability of samples was investigated. The results show that the Hg 2+ adsorption capacity of samples increased significantly with increases in micropores and acidic functional groups and that the adsorption process was exothermic. Different models and thermodynamic parameters were evaluated to establish the mechanisms. It was concluded that the adsorption occurred through a monolayer mechanism by a two-speed process involving both rapid adsorption and slow adsorption. The adsorption rate was determined by chemical reaction

  6. Novel Al-doped carbon nanotubes with adsorption and coagulation promotion for organic pollutant removal.

    Science.gov (United States)

    Kang, Dongjuan; Yu, Xiaolin; Ge, Maofa; Xiao, Feng; Xu, Hui

    2017-04-01

    Al-doped carbon nanotubes (Al-doped CNTs) were prepared as a multifunctional integrated material of adsorbent and coagulant aid for organic pollutant removal from aqueous solution. It was observed that aluminum species were dispersed homogeneously on the surface of CNTs, and mainly anchored onto defect structures of the CNTs. The introduction of aluminium efficiently improved adsorption ability for methyl orange (MO) onto the CNTs, and maximum adsorption capacity calculated from the Langmuir isotherm model can reach 69.7mg/g. The MO adsorption kinetics can be better described by the pseudo-second-order and pore diffusion kinetic models, and the diffusion of MO anions into pores of the Al-doped CNT adsorbent should be the rate-determining step. Thermodynamic analyses indicated that the adsorption of MO onto Al-CNTs-2.0 was endothermic and spontaneous. Moreover, adsorption capacity for MO on the Al-doped CNTs was evidently dependent on the CNT dose, solution pH and adsorbent dose. From the perspective of low-cost and multifunctional, suspension obtained during the Al-doped CNT adsorbent preparation, was tested as coagulant to remove humic acid (HA). A significant observation is that the suspension exhibited an excellent coagulation performance for HA, because abundant aluminous polymer and Al-doped CNTs existed in the suspension. Copyright © 2016. Published by Elsevier B.V.

  7. The application of graphitic carbon nitride for the adsorption of Pb2+ ion from aqueous solution

    Science.gov (United States)

    Zhu, Lin; You, Liangjun; Wang, Ya; Shi, Zhaoxin

    2017-07-01

    This study appraised the potential application of graphitic carbon nitride (g-C3N4) as an adsorbent for removal of Pb2+ ion from aqueous solution. The g-C3N4 was prepared by direct calcination of the low-cost melamine, and its morphology and microstructure were analyzed. Moreover, the effects of initial solution pH, initial Pb2+ ion concentration, adsorption time, and adsorbent dosage on the adsorption properties of the g-C3N4 were investigated. Two widely used isotherm models were used to describe the experimental equilibrium data, and the Freundlich isotherm model described well. Two widely used kinetic models were used to the fit of the adsorption experimental data, and the pseudo-second-order kinetic model fitted well. The maximum adsorption percentage and maximum adsorption capacity were 98.5% and 7.4 mg g-1, respectively. In addition, the recycling of g-C3N4 for the removal of Pb2+ was investigated, and the results indicated that g-C3N4 owned a good reusability.

  8. Chromium (Ⅵ) removal from aqueous solutions through powdered activated carbon countercurrent two-stage adsorption.

    Science.gov (United States)

    Wang, Wenqiang

    2018-01-01

    To exploit the adsorption capacity of commercial powdered activated carbon (PAC) and to improve the efficiency of Cr(VI) removal from aqueous solutions, the adsorption of Cr(VI) by commercial PAC and the countercurrent two-stage adsorption (CTA) process was investigated. Different adsorption kinetics models and isotherms were compared, and the pseudo-second-order model and the Langmuir and Freundlich models fit the experimental data well. The Cr(VI) removal efficiency was >80% and was improved by 37% through the CTA process compared with the conventional single-stage adsorption process when the initial Cr(VI) concentration was 50 mg/L with a PAC dose of 1.250 g/L and a pH of 3. A calculation method for calculating the effluent Cr(VI) concentration and the PAC dose was developed for the CTA process, and the validity of the method was confirmed by a deviation of <5%. Copyright © 2017. Published by Elsevier Ltd.

  9. Adsorption of Paraquat Dichloride by Graphitic Carbon Nitride Synthesized from Melamine Scraps

    Science.gov (United States)

    Watcharenwong, A.; Kaeokan, A.; Rammaroeng, R.; Upama, P.; Kajitvichyanukul, P.

    2017-07-01

    In this research, graphitic carbon nitride (g-C3N4) was synthesized from useless melamine scraps. Mixture of melamine powder and urea was directly burned in the muffle furnace at 550 °C. Later as-synthesized g-C3N4 was modified with hydrochloric acid. The g-C3N4 powder was characterized by several techniques including X-ray diffraction, scanning electron microscope, and specific surface area analyser. Adsorption of the herbicide paraquat from an aqueous solution to suspended particles of g-C3N4 was investigated, taking into consideration several parameters such as initial concentration of paraquat, initial pH, and dosage of g-C3N4. The results showed that with the same amount of g-C3N4, the increase in the paraquat concentration caused the reduction in the removal efficiency and the higher the amount of g-C3N4, the less residual paraquat remained in the bulk solution. G-C3N4 showed better adsorption behaviour in the basic condition. Finally, Langmuir and Freundlich adsorption isotherms were also evaluated. Paraquat adsorption by g-C3N4 was in accordance with Langmuir more than Freundlich adsorption isotherm.

  10. Activated carbon adsorption of quinolone antibiotics in water: Performance, mechanism, and modeling.

    Science.gov (United States)

    Fu, Hao; Li, Xuebing; Wang, Jun; Lin, Pengfei; Chen, Chao; Zhang, Xiaojian; Suffet, I H Mel

    2017-06-01

    The extensive use of antibiotics has led to their presence in the aquatic environment, and introduces potential impacts on human and ecological health. The capability of powdered activated carbon (PAC) to remove six frequently used quinolone (QN) antibiotics during water treatment was evaluated to improve drinking water safety. The kinetics of QN adsorption by PAC was best described by a pseudo second-order equation, and the adsorption capacity was well described by the Freundlich isotherm equation. Isotherms measured at different pH showed that hydrophobic interaction, electrostatic interaction, and π-π dispersion force were the main mechanisms for adsorption of QNs by PAC. A pH-dependent isotherm model based on the Freundlich equation was developed to predict the adsorption capacity of QNs by PAC at different pH values. This model had excellent prediction capabilities under different laboratory scenarios. Small relative standard derivations (RSDs), i.e., 0.59%-0.92% for ciprofloxacin and 0.09%-3.89% for enrofloxacin, were observed for equilibrium concentrations above the 0.3mg/L level. The RSDs increased to 11.9% for ciprofloxacin and 32.1% for enrofloxacin at μg/L equilibrium levels, which is still acceptable. This model could be applied to predict the adsorption of other chemicals having different ionized forms. Copyright © 2016. Published by Elsevier B.V.

  11. [Study of the adsorption behaviors of plasma proteins on the single-walled carbon nanotubes nonwoven].

    Science.gov (United States)

    Meng, Jie; Song, Li; Meng, Jie; Kong, Hua; Wang, Chaoying; Guo, Xiaotian; Xu, Haiyan; Xie, Sishen

    2007-02-01

    Single walled carbon nanotubes (SWNT) have attracted increasing research interests for the purpose of biomedical application because they provide not only nanostructured topography, but also chemical composition of pure carbon atoms, as well as ultra high strength and excellent flexibility. Regarding the interactions of nanomaterials to biological systems, non-specific adsorption of plasma proteins is one of the most important issues to be concerned, which plays a crucial role that would determine how biological systems response to the biomaterials. Motivated by application of SWNT materials in biomedical fields, in this study, the adsorption behaviors of plasma proteins on the surface of SWNT nonwoven, prepared directly by floating chemical vapor observation and energy deposition method were investigated by means of scanning electron microscope (SEM), dispersive X-ray (EDX) analysis and ELISA. Results indicated the SWNT non-woven showed a clear adsorption preference of fibrinogen over albumin. There was no human serum albumin detected using above analysis methods on the SWNT nonwoven even incubated in the albumin solution of 4 mg/ml. While more than 0.15 microg of human fibrinogen was detected by ELISA on the SWNT nonwoven with area of 40 mm x 40 mm incubated in the fibrinogen solution of 5 microg/ml. In addition, IgG of sheep-anti-human serum fibrinogen exhibited strong nonspecific adsorption on the surface of SWNT nonwoven. The adsorption behaviors are different significantly from those of other carbon materials and conventional biomaterials. The unique interaction of SWNT nonwoven to plasma proteins is of significance to further studies of blood cells responses.

  12. Carbon nanotube embedded PVDF membranes: Effect of solvent composition on the structural morphology for membrane distillation

    Science.gov (United States)

    Mapunda, Edgar C.; Mamba, Bhekie B.; Msagati, Titus A. M.

    2017-08-01

    Rapid population increase, growth in industrial and agricultural sectors and global climate change have added significant pressure on conventional freshwater resources. Tapping freshwater from non-conventional water sources such as desalination and wastewater recycling is considered as sustainable alternative to the fundamental challenges of water scarcity. However, affordable and sustainable technologies need to be applied for the communities to benefit from the treatment of non-conventional water source. Membrane distillation is a potential desalination technology which can be used sustainably for this purpose. In this work multi-walled carbon nanotube embedded polyvinylidene fluoride membranes for application in membrane distillation desalination were prepared via non-solvent induced phase separation method. The casting solution was prepared using mixed solvents (N, N-dimethylacetamide and triethyl phosphate) at varying ratios to study the effect of solvent composition on membrane morphological structures. Membrane morphological features were studied using a number of techniques including scanning electron microscope, atomic force microscope, SAXSpace tensile strength analysis, membrane thickness, porosity and contact angle measurements. It was revealed that membrane hydrophobicity, thickness, tensile strength and surface roughness were increasing as the composition of N, N-dimethylacetamide in the solvent was increasing with maximum values obtained between 40 and 60% N, N-dimethylacetamide. Internal morphological structures were changing from cellular structures to short finger-like and sponge-like pores and finally to large macro void type of pores when the amount of N, N-dimethylacetamide in the solvent was changed from low to high respectively. Multi-walled carbon nanotube embedded polyvinylidene fluoride membranes of desired morphological structures and physical properties can be synthesized by regulating the composition of solvents used to prepare the

  13. Kinetics of adsorption of dyes from aqueous solution using activated carbon prepared from waste apricot

    International Nuclear Information System (INIS)

    Onal, Yunus

    2006-01-01

    Adsorbent (WA11Zn5) has been prepared from waste apricot by chemical activation with ZnCl 2 . Pore properties of the activated carbon such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N 2 adsorption and DFT plus software. Adsorption of three dyes, namely, Methylene Blue (MB), Malachite Green (MG), Crystal Violet (CV), onto activated carbon in aqueous solution was studied in a batch system with respect to contact time, temperature. The kinetics of adsorption of MB, MG and CV have been discussed using six kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, the modified Freundlich equation. Kinetic parameters and correlation coefficients were determined. It was shown that the second-order kinetic equation could describe the adsorption kinetics for three dyes. The dyes uptake process was found to be controlled by external mass transfer at earlier stages (before 5 min) and by intraparticle diffusion at later stages (after 5 min). Thermodynamic parameters, such as ΔG, ΔH and ΔS, have been calculated by using the thermodynamic equilibrium coefficient obtained at different temperatures and concentrations. The thermodynamics of dyes-WA11Zn5 system indicates endothermic process

  14. Excellent adsorption performance of dibenzothiophene on functionalized low-cost activated carbons with different oxidation methods.

    Science.gov (United States)

    Yu, Zhan; Wang, Dan; Yang, Yue; Meng, Xuan; Liu, Naiwang; Shi, Li

    2018-02-12

    Low-cost activated carbon (KAC) was functionalized by HNO 3 , (NH 4 ) 2 S 2 O 8 and air oxidation, respectively, to remove dibenzothiophene (DBT) from model fuel. The changes in physical and chemical properties of these activated carbons were characterized by thermal analysis, elemental analysis, nitrogen adsorption apparatus, Raman spectra, scanning electron microscope and Boehm's titration method. HNO 3 and (NH 4 ) 2 S 2 O 8 oxidation result in a significant decrease in pore structure, while air oxidation only causes slight pore reduction due to the re-activation by O 2 . The oxygen-containing functional groups (OFGs) increase markedly after oxidative modification, in which (NH 4 ) 2 S 2 O 8 oxidation is considered as the most efficient method with respect to the introduction of OFGs. HNO 3 and (NH 4 ) 2 S 2 O 8 oxidation are more selective to generate carboxyls and lactones, whereas air oxidation creates more phenols, carbonyls and ethers. The DBT adsorption capacity follows the order: NAC (HNO 3 -oxidized KAC) > OAC (air-oxidized KAC) > KAC > SAC ((NH 4 ) 2 S 2 O 8 -oxidized KAC), implying the introduction of OFGs is beneficial for the DBT adsorption process, especially for selectivity, but excessive OFGs have a negative effect on the removal of DBT. Thus, to achieve high DBT adsorption performance, there should be a trade-off between the micropore volume and the OFGs amount.

  15. Removal of cyanobacteria toxins from drinking water by adsorption on activated carbon fibers

    Directory of Open Access Journals (Sweden)

    Eden Cavalcanti de Albuquerque Júnior

    2008-09-01

    Full Text Available Natural fibers from macadamia nut shell, dried coconut shell endocarp, unripe coconut mesocarp, sugarcane bagasse and pine wood residue were used to prepare activated carbon fibers (ACF with potential application for removing microcystins. The ACF from pine wood and sugar cane bagasse were used to remove [D-Leucine¹]MCYST-LR from water. After 10 minutes of contact time, more than 98% of toxin was removed by the ACF. The microcystin adsorption monolayer, q m, in the ACF recovered 200 and 161 µg.mg-1, with the Langmuir adsorption constant, K L, of 2.33 and 1.23 L.mg-1. Adsorption of [D-Leucine¹]MCYST-LR in continuous process was studied for a fixed-bed ACF prepared from coconut shell and sugar cane bagasse and for two commercial activated carbon samples from treatment water plants of two Brazilian hemodialysis centers. Saturation of the beds occurred after 80 to 320 minutes, and the adsorption capacity for that toxin varied from 4.11 to 12.82 µg.mg-1.

  16. Significance of Graphitic Surfaces in Aurodicyanide Adsorption by Activated Carbon: Experimental and Computational Approach

    Science.gov (United States)

    Bhattacharyya, Dhiman; Depci, Tolga; Prisbrey, Keith; Miller, Jan D.

    Despite tremendous developments in industrial use of activated carbon (AC) for gold adsorption, specific aurodicyanide [Au(CN)2-] adsorption sites on the carbon have intrigued researchers. The graphitic structure of AC has been well established. Previously radiochemical and now, XPS and Raman characterizations have demonstrated higher site-specific gold adsorption on graphitic edges. Morphological characterizations have revealed the presence of slit-pores (5-10 Å). Molecular-dynamics-simulation (MDS) performed on graphitic slit-pores illustrated gold-cyanide ion-pair preferentially adsorbs on edges. Ab-initio simulations predicted lower barrier for electron sharing in pores with aurodic yanide, indicating tighter bonding than graphitic surface and was well supported by Gibbs energy calculations too. Interaction energy as function of the separation distance indicated tighter bonding of gold cyanide to the graphite edges than water molecules. Selective adsorption of aurodicyanide ion-pair seems to be related to low polarity of gold complex and its accommodation at graphitic edges.

  17. The effect of the oxygen dissolved in the adsorption of gold in activated carbon

    International Nuclear Information System (INIS)

    Navarro, P.; Wilkomirsky, I.

    1999-01-01

    The effect of the oxygen dissolved on the adsorption of gold in a activated carbon such as these used for carbon in pulp (CIP) and carbon in leach (CIL) processes were studied. The research was oriented to dilucidate the effect of the oxygen dissolved in the gold solution on the kinetics and distribution of the gold adsorbed in the carbon under different conditions of ionic strength, pH and gold concentration. It was found that the level of the oxygen dissolved influences directly the amount of gold adsorbed on the activated carbon, being this effect more relevant for low ionic strength solutions. The pH and initial gold concentration has no effect on this behavior. (Author) 16 refs

  18. New Adsorption Cycles for Carbon Dioxide Capture and Concentration

    Energy Technology Data Exchange (ETDEWEB)

    James Ritter; Armin Ebner; Steven Reynolds Hai Du; Amal Mehrotra

    2008-07-31

    The objective of this three-year project was to study new pressure swing adsorption (PSA) cycles for CO{sub 2} capture and concentration at high temperature. The heavy reflux (HR) PSA concept and the use of a hydrotalcite like (HTlc) adsorbent that captures CO{sub 2} reversibly at high temperatures simply by changing the pressure were two key features of these new PSA cycles. Through the completion or initiation of nine tasks, a bench-scale experimental and theoretical program has been carried out to complement and extend the process simulation study that was carried out during Phase I (DE-FG26-03NT41799). This final report covers the entire project from August 1, 2005 to July 31, 2008. This program included the study of PSA cycles for CO{sub 2} capture by both rigorous numerical simulation and equilibrium theory analysis. The insight gained from these studies was invaluable toward the applicability of PSA for CO{sub 2} capture, whether done at ambient or high temperature. The rigorous numerical simulation studies showed that it is indeed possible to capture and concentrate CO{sub 2} by PSA. Over a wide range of conditions it was possible to achieve greater than 90% CO{sub 2} purity and/or greater than 90% CO{sub 2} recovery, depending on the particular heavy reflux (HR) PSA cycle under consideration. Three HR PSA cycles were identified as viable candidates for further study experimentally. The equilibrium theory analysis, which represents the upper thermodynamic limit of the performance of PSA process, further validated the use of certain HR PSA cycles for CO{sub 2} capture and concentration. A new graphical approach for complex PSA cycle scheduling was also developed during the course of this program. This new methodology involves a priori specifying the cycle steps, their sequence, and the number of beds, and then following a systematic procedure that requires filling in a 2-D grid based on a few simple rules, some heuristics and some experience. It has been

  19. Adsorption of organic contaminants by graphene nanosheets, carbon nanotubes and granular activated carbons under natural organic matter preloading conditions.

    Science.gov (United States)

    Ersan, Gamze; Kaya, Yasemin; Apul, Onur G; Karanfil, Tanju

    2016-09-15

    The effect of NOM preloading on the adsorption of phenanthrene (PNT) and trichloroethylene (TCE) by pristine graphene nanosheets (GNS) and graphene oxide nanosheet (GO) was investigated and compared with those of a single-walled carbon nanotube (SWCNT), a multi-walled carbon nanotube (MWCNT), and two coal based granular activated carbons (GACs). PNT uptake was higher than TCE by all adsorbents on both mass and surface area bases. This was attributed to the hydrophobicity of PNT. The adsorption capacities of PNT and TCE depend on the accessibility of the organic molecules to the inner regions of the adsorbent which was influenced from the molecular size of OCs. The adsorption capacities of all adsorbents decreased as a result of NOM preloading due to site competition and/or pore/interstice blockage. However, among all adsorbents, GO was generally effected least from the NOM preloading for PNT, whereas there was not observed any trend of NOM competition with a specific adsorbent for TCE. In addition, SWCNT was generally affected most from the NOM preloading for TCE and there was not any trend for PNT. The overall results indicated that the fate and transport of organic contaminants by GNSs and CNTs type of nanoadsorbents and GACs in different natural systems will be affected by water quality parameters, characteristics of adsorbent, and properties of adsorbate. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Porous carbon with small mesoporesas an ultra-high capacity adsorption medium

    Science.gov (United States)

    Gao, Biaofeng; Zhou, Haitao; Chen, De; Yang, Jianhong

    2017-10-01

    Resins (732-type), abundant and inexpensive resources were used to prepare porous carbon with small mesopores (CSM) by carbonization and post-chemical-activation with potassium hydroxide (KOH). The N2 adsorption measurements revealed that CSM had high surface areas (1776.5 m2 g-1), large pore volumes (1.10 cm3 g-1), and nearly optimal narrow small mesopore sizes ranging from 2 to 7 nm. CSM was used as adsorbent to investigate the adsorption behavior for Rhodamine B (RhB). Due to the optimal pore size distributions (PSD), intensive-stacking interaction, S-doped, and electrostatic attraction, the CSM exhibited an ultra-high-capacity of 1590 mg g-1 for RhB in aqueous solutions.

  1. Pore size distribution and supercritical hydrogen adsorption in activated carbon fibers

    Science.gov (United States)

    Purewal, J. J.; Kabbour, H.; Vajo, J. J.; Ahn, C. C.; Fultz, B.

    2009-05-01

    Pore size distributions (PSD) and supercritical H2 isotherms have been measured for two activated carbon fiber (ACF) samples. The surface area and the PSD both depend on the degree of activation to which the ACF has been exposed. The low-surface-area ACF has a narrow PSD centered at 0.5 nm, while the high-surface-area ACF has a broad distribution of pore widths between 0.5 and 2 nm. The H2 adsorption enthalpy in the zero-coverage limit depends on the relative abundance of the smallest pores relative to the larger pores. Measurements of the H2 isosteric adsorption enthalpy indicate the presence of energy heterogeneity in both ACF samples. Additional measurements on a microporous, coconut-derived activated carbon are presented for reference.

  2. Pore size distribution and supercritical hydrogen adsorption in activated carbon fibers

    International Nuclear Information System (INIS)

    Purewal, J J; Kabbour, H; Ahn, C C; Fultz, B; Vajo, J J

    2009-01-01

    Pore size distributions (PSD) and supercritical H 2 isotherms have been measured for two activated carbon fiber (ACF) samples. The surface area and the PSD both depend on the degree of activation to which the ACF has been exposed. The low-surface-area ACF has a narrow PSD centered at 0.5 nm, while the high-surface-area ACF has a broad distribution of pore widths between 0.5 and 2 nm. The H 2 adsorption enthalpy in the zero-coverage limit depends on the relative abundance of the smallest pores relative to the larger pores. Measurements of the H 2 isosteric adsorption enthalpy indicate the presence of energy heterogeneity in both ACF samples. Additional measurements on a microporous, coconut-derived activated carbon are presented for reference.

  3. Hydrogen Adsorption in Flame Synthesized and Lithium Intercalated Carbon Nanofibers--A Comparative Study.

    Science.gov (United States)

    Dhand, Vivek; Prasad, J Sarada; Rao, Venkateswer M; Kalluri, Sujith; Jain, Pawan Kumar; Sreedhar, B

    2015-01-01

    Carbon nanofibers (CNF) have been synthesized under partial combustion conditions in a flame reactor using different mixtures of hydrocarbon gases in the presence and absence of precursors. The hydrogen (H2) adsorption studies have been carried out using a high pressure Sievert's apparatus maintained at a constant temperature (24 degrees C). The flame synthesized CNFs showed high degree of H2 adsorption capacities at 100 atm pressure. The highest H2 capacities recorded have been 4.1 wt% [for CNF produced by liquefied petroleum gas (LPG)-Air (E-17)], 3.7 wt% [for nano carbons produced by Methane-Acetylene-Air (EMAC-4)] and 5.04 wt% for [Lithium intercalated sample (Li-EMAC-4)] respectively.

  4. A method for creating microporous carbon materials with excellent CO2-adsorption capacity and selectivity.

    Science.gov (United States)

    Qian, Dan; Lei, Cheng; Wang, En-Min; Li, Wen-Cui; Lu, An-Hui

    2014-01-01

    A new synthetic approach for the fabrication of microporous carbon materials (HCMs) by using discrete chelating zinc species as dynamic molecular porogens to create extra micropores that enhance their CO2-adsorption capacity and selectivity is reported. During the carbonization process, the evaporation of the in situ-formed Zn species would create additional nanochannels that contribute to the additional micropore volume for CO2 adsorption. The resultant HCMs show an increased number of micropores, with sizes in the range 0.7-1.0 nm and a high CO2 -adsorption capacity of 5.4 mmol g(-1) (23.8 wt%) at 273 K and 3.8 mmol g(-1) (16.7 wt%) at 298 K and 1 bar, which are superior to those of most carbon-based adsorbents with N-doping or high specific surface areas. Dynamic gas-separation measurements, by using 16% CO2 in N2 (v/v) as a feedstock, demonstrated that CO2 could be effectively separated from N2 under ambient conditions and shows a high separation factor (S(CO2)/N2=110) for CO2 over N2, thereby reflecting a strongly competitive CO2 -adsorption capacity. If the feedstock contained water vapor, the dynamic capacity of CO2 was almost identical to that measured under dry conditions, thus indicating that the carbon material had excellent tolerance to humidity. Easy CO2 release could be realized by purging an argon flow through the fixed-bed adsorber at 298 K, thus indicating good regeneration ability. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Removal of cyanobacterial amino acids in water treatment by activated carbon adsorption

    Czech Academy of Sciences Publication Activity Database

    Čermáková, Lenka; Kopecká, Ivana; Pivokonský, Martin; Pivokonská, Lenka; Janda, V.

    2017-01-01

    Roč. 173, č. 1 (2017), s. 330-338 ISSN 1383-5866 Institutional support: RVO:67985874 Keywords : amino acids * activated carbon * adsorption * algal organic matter * water treatment * coagulation * microcystis aeruginosa * peptides/proteins * permanganate pre-oxidation * water treatment Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 3.359, year: 2016

  6. The effect of pore size dimensions in isoreticular zeolites on carbon dioxide adsorption heats

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Shamzhy, Mariya; Kubů, Martin; Čejka, Jiří

    Roč. 24, MAR2018 ( 2018 ), s. 157-163 ISSN 2212-9820 R&D Projects: GA ČR GBP106/12/G015 EU Projects: European Commission(XE) 640979 - ShaleXenvironmenT Institutional support: RVO:61388955 Keywords : UTL zeolite * IPC-n zeolites * Carbon dioxide adsorption Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.292, year: 2016

  7. Removal of cyanobacterial amino acids in water treatment by activated carbon adsorption

    Czech Academy of Sciences Publication Activity Database

    Čermáková, Lenka; Kopecká, Ivana; Pivokonský, Martin; Pivokonská, Lenka; Janda, V.

    2017-01-01

    Roč. 173, č. 1 (2017), s. 330-338 ISSN 1383-5866 Institutional support: RVO:67985874 Keywords : amino acids * activated carbon * adsorption * algal organic matter * water treatment * coagulation * microcystis aeruginosa * peptides/proteins * permanganate pre- oxidation * water treatment Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 3.359, year: 2016

  8. The effect of pore size dimensions in isoreticular zeolites on carbon dioxide adsorption heats

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Shamzhy, Mariya; Kubů, Martin; Čejka, Jiří

    2018-01-01

    Roč. 24, MAR2018 (2018), s. 157-163 ISSN 2212-9820 R&D Projects: GA ČR GBP106/12/G015 EU Projects: European Commission(XE) 640979 - ShaleXenvironmenT Institutional support: RVO:61388955 Keywords : UTL zeolite * IPC-n zeolites * Carbon dioxide adsorption Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.292, year: 2016

  9. Adsorption, polymerization and decomposition of acetaldehyde on clean and carbon-covered Rh(111) surfaces

    Science.gov (United States)

    Kovács, Imre; Farkas, Arnold Péter; Szitás, Ádám; Kónya, Zoltán; Kiss, János

    2017-10-01

    The adsorption and dissociation of acetaldehyde were investigated on clean and carbon-covered Rh(111) single crystal surfaces by electron energy loss spectroscopy (EELS), temperature programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS) and work function (Δφ) measurements. Acetaldehyde is a starting material for the catalytic production of many important chemicals and investigation of its reactions motivated by environmental purposes too. The adsorption of acetaldehyde on clean Rh(111) surface produced various types of adsorption forms. η1-(O)-CH3CHOa and η2-(O,C)-CH3CHOa are developing and characterized by HREELS. η1-CH3CHOa partly desorbed at Tp = 150 K, another part of these species are incorporated in trimer and linear 2D polimer species. The desorption of trimers (at amu 132) were observed in TPD with a peak maximum at Tp = 225 K. Above this temperature acetaldehyde either desorbed or bonded as a stable surface intermediate (η2-CH3CHOa) on the rhodium surface. The molecules decomposed to adsorbed products, and only hydrogen and carbon monoxide were analyzed in TPD. Surface carbon decreased the uptake of adsorbed acetaldehyde, inhibited the formation of polymers, nevertheless, it induced the Csbnd O bond scission and CO formation with 40-50 K lower temperature after higher acetaldehyde exposure.

  10. Complete treatment of olive pomace leachate by coagulation, activated-carbon adsorption and electrochemical oxidation.

    Science.gov (United States)

    Mavros, Michael; Xekoukoulotakis, Nikolaos P; Mantzavinos, Dionissios; Diamadopoulos, Evan

    2008-06-01

    A battery scheme comprising sequential alum coagulation, activated-carbon adsorption and electrochemical oxidation over boron-doped diamond electrodes to mineralize a leachate from olive pomace processing is demonstrated. The effect of coagulant and adsorbent concentration on treatment efficiency was assessed in the range 0.1-50 mM Al(3+) and 2.5-50 g/L activated-carbon and optimal conditions were established. Coagulation at 7.5mM Al(3+) resulted in substantial solids and color removal (i.e. 80% and 93%, respectively). This was accompanied by only 30% chemical oxygen demand (COD) reduction (initial COD was about 3,500 mg/L). The latter increased to 80% though when coagulation was coupled with adsorption at 25 g/L activated carbon. Electrochemical oxidation of the original effluent for 360 min led to 63% and 82% COD reduction at 10 and 20A current intensity, respectively. When this process was tested as a polishing stage following coagulation and adsorption, overall COD removal reached values of 92% and 97%, respectively. The final effluent was also colorless and solids free. However, the treated effluent still exhibited ecotoxicity possibly due to the formation of ecotoxic oxidation products.

  11. ADSORPTION OF METHYLENE BLUE FROM AQUEOUS SOLUTION ON ACTIVATED CARBON PRODUCED FROM SOYBEAN OIL CAKE BY KOH ACTIVATION

    OpenAIRE

    Turgay Tay,; Murat Erdem,; Burak Ceylan,; Selhan Karagöz

    2012-01-01

    This study presents the adsorption behavior of the methylene blue (MB) dye onto the activated carbon produced from soybean oil cake by chemical activation with KOH at 800 °C. The adsorption isotherms, kinetic models, and thermodynamic parameters of the adsorption were studied. The Langmuir isotherm showed a better fit than the Freundlich isotherm. The adsorption rate was described by pseudo-second-order kinetics. The negative values of ΔG° and the positive values of ΔH° indicate that the adso...

  12. Estimation of adsorption energies using VOCs' molecular properties and activated carbons' physical characteristics

    International Nuclear Information System (INIS)

    Giraudet, S.; Pre, P.; Le Cloirec, P.

    2005-01-01

    Adsorption of Volatile Organic Compounds (VOCs) by Granular Activated Carbon (GAC) is a conventional process for recovery of solvents from gas effluents. Such a treatment is achieved in cyclic batch adsorption systems, in which the adsorbent bed is alternately saturated and regenerated. However, the exothermal nature of adsorption causes a reduction in the dynamic adsorption capacity of the bed, and thus a decrease in the overall efficiency of the recovery process. Furthermore, the local temperature rises may become hazardous at high levels of pollutant concentrations, bringing about safety risk with bed ignition. This study points out the properties of VOCs and GACs that play a major role on the heat flux released during adsorption. For that purpose, a statistical analysis was conducted on a database representative of the changes in the molar integral adsorption enthalpies measured on 8 different commercials GACs, for a wide variety of VOCs. The adsorption enthalpies were determined by TG-DSC (thermal gravimetry analysis coupled to differential scanning calorimetry), by flowing helium loaded with 50 g.m 3 of solvent through the adsorbent sample. Afterwards, two statistical models were applied on the database so generated and were compared in terms of prediction skill: Multi-Linear Regression (MLR) and Neural Network (NN). From the MLR approach, the polarizability, the heat of vaporization, the ionization potential, and the surface tension of the VOC were discriminated among other molecular properties, whilst the average micropore radius was shown to be the most influent adsorbent characteristic on the potential energy of the interactions with an organic molecule. The major influence of these properties was explained in the light of the mechanisms that are involved during progressive coverage of the adsorbent. Physisorption, i.e. dispersion forces between the adsorbate and the pore walls, and capillary condensation occurring in meso-pores were put forward. The MLR

  13. Barriers to Superfast Water Transport in Carbon Nanotube Membranes

    DEFF Research Database (Denmark)

    Walther, Jens Honore; Ritos, Konstantinos; Cruz-Chu, Eduardo R.

    2013-01-01

    Carbon nanotube (CNT) membranes hold the promise of extraordinary fast water transport for applications such as energy efficient filtration and molecular level drug delivery. However, experiments and computations have reported flow rate enhancements over continuum hydrodynamics that contradict each...... over the continuum predictions. These rates are far below those reported experimentally. The results suggest that the reported superfast water transport rates cannot be attributed to interactions of water with pristine CNTs alone....

  14. Carbon key-properties for microcystin adsorption in drinking water treatment: structure or surface chemistry?

    OpenAIRE

    Júlio, Maria de Fátima de Jesus Leal

    2011-01-01

    Dissertação para Obtenção de Grau de Mestre em Engenharia Química e Bioquímica The carbon key-properties (structure and surface chemistry) for microcystin-LR (MC-LR) adsorption onto activated carbon were investigated. Waters with an inorganic background matrix approaching that of the soft natural water (2.5 mM ionic strength) were used. Also, model waters with controlled ionic make-up and NOM surrogate with similar size of MC-LR (tannic acid - TA) with MC-LR extracts were tested with activ...

  15. Nanoplasmonic Sensing at the Carbon-Bio Interface: Study of Protein Adsorption at Graphitic and Hydrogenated Carbon Surfaces.

    Science.gov (United States)

    Zen, Federico; Karanikolas, Vasilios D; Behan, James A; Andersson, Jenny; Ciapetti, Guido; Bradley, A Louise; Colavita, Paula E

    2017-05-02

    Various forms of carbon are known to perform well as biomaterials in a variety of applications and an improved understanding of their interactions with biomolecules, cells, and tissues is of interest for improving and tailoring their performance. Nanoplasmonic sensing (NPS) has emerged as a powerful technique for studying the thermodynamics and kinetics of interfacial reactions. In this work, the in situ adsorption of two proteins, bovine serum albumin and fibrinogen, were studied at carbon surfaces with differing chemical and optical properties using nanoplasmonic sensors. The carbon material was deposited as a thin film onto NPS surfaces consisting of 100 nm Au nanodisks with a localized plasmon absorption peak in the visible region. Carbon films were fully characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and spectroscopic ellipsometry. Two types of material were investigated: amorphous carbon (a-C), with high graphitic content and high optical absorptivity, and hydrogenated amorphous carbon (a-C:H), with low graphitic content and high optical transparency. The optical response of the Au/carbon NPS elements was modeled using the finite difference time domain (FDTD) method, yielding simulated analytical sensitivities that compare well with those observed experimentally at the two carbon surfaces. Protein adsorption was investigated on a-C and a-C:H, and the protein layer thicknesses were obtained from FDTD simulations of the expected response, yielding values in the 1.8-3.3 nm range. A comparison of the results at a-C and a-C:H indicates that in both cases fibrinogen layers are thicker than those formed by albumin by up to 80%.

  16. Removal of Phenolic Compounds from Water Using Sewage Sludge-Based Activated Carbon Adsorption: A Review

    Science.gov (United States)

    Jarrah, Nabeel; Zubair, Mukarram; Alagha, Omar

    2017-01-01

    Due to their industrial relevance, phenolic compounds (PC) are amongst the most common organic pollutants found in many industrial wastewater effluents. The potential detrimental health and environmental impacts of PC necessitate their removal from wastewater to meet regulatory discharge standards to ensure meeting sustainable development goals. In recent decades, one of the promising, cost-effective and environmentally benign techniques for removal of PC from water streams has been adsorption onto sewage sludge (SS)-based activated carbon (SBAC). This is attributed to the excellent adsorptive characteristics of SBAC and also because the approach serves as a strategy for sustainable management of huge quantities of different types of SS that are in continual production globally. This paper reviews conversion of SS into activated carbons and their utilization for the removal of PC from water streams. Wide ranges of topics which include SBAC production processes, physicochemical characteristics of SBAC, factors affecting PC adsorption onto SBAC and their uptake mechanisms as well as the regeneration potential of spent SBAC are covered. Although chemical activation techniques produce better SBAC, yet more research work is needed to harness advances in material science to improve the functional groups and textural properties of SBAC as well as the low performance of physical activation methods. Studies focusing on PC adsorptive performance on SBAC using continuous mode (that are more relevant for industrial applications) in both single and multi-pollutant aqueous systems to cover wide range of PC are needed. Also, the potentials of different techniques for regeneration of spent SBAC used for adsorption of PC need to be assessed in relation to overall economic evaluation within realm of environmental sustainability using life cycle assessment. PMID:28934127

  17. Removal of Phenolic Compounds from Water Using Sewage Sludge-Based Activated Carbon Adsorption: A Review.

    Science.gov (United States)

    Mu'azu, Nuhu Dalhat; Jarrah, Nabeel; Zubair, Mukarram; Alagha, Omar

    2017-09-21

    Due to their industrial relevance, phenolic compounds (PC) are amongst the most common organic pollutants found in many industrial wastewater effluents. The potential detrimental health and environmental impacts of PC necessitate their removal from wastewater to meet regulatory discharge standards to ensure meeting sustainable development goals. In recent decades, one of the promising, cost-effective and environmentally benign techniques for removal of PC from water streams has been adsorption onto sewage sludge (SS)-based activated carbon (SBAC). This is attributed to the excellent adsorptive characteristics of SBAC and also because the approach serves as a strategy for sustainable management of huge quantities of different types of SS that are in continual production globally. This paper reviews conversion of SS into activated carbons and their utilization for the removal of PC from water streams. Wide ranges of topics which include SBAC production processes, physicochemical characteristics of SBAC, factors affecting PC adsorption onto SBAC and their uptake mechanisms as well as the regeneration potential of spent SBAC are covered. Although chemical activation techniques produce better SBAC, yet more research work is needed to harness advances in material science to improve the functional groups and textural properties of SBAC as well as the low performance of physical activation methods. Studies focusing on PC adsorptive performance on SBAC using continuous mode (that are more relevant for industrial applications) in both single and multi-pollutant aqueous systems to cover wide range of PC are needed. Also, the potentials of different techniques for regeneration of spent SBAC used for adsorption of PC need to be assessed in relation to overall economic evaluation within realm of environmental sustainability using life cycle assessment.

  18. Ciprofloxacin adsorption on graphene and granular activated carbon: kinetics, isotherms, and effects of solution chemistry.

    Science.gov (United States)

    Zhu, Xuan; Tsang, Daniel C W; Chen, Feng; Li, Shiyu; Yang, Xin

    2015-01-01

    Ciprofloxacin (CIP) is a commonly used antibiotic and widely detected in wastewaters and farmlands nowadays. This study evaluated the efficacy of next-generation adsorbent (graphene) and conventional adsorbent (granular activated carbon, GAC) for CIP removal. Batch experiments and characterization tests were conducted to investigate the adsorption kinetics, equilibrium isotherms, thermodynamic properties, and the influences of solution chemistry (pH, ionic strength, natural organic matter (NOM), and water sources). Compared to GAC, graphene showed significantly faster adsorption and reached equilibrium within 3 min, confirming the rapid access of CIP into the macroporous network of high surface area of graphene as revealed by the Brunner-Emmet-Teller measurements analysis. The kinetics was better described by a pseudo-second-order model, suggesting the importance of the initial CIP concentration related to surface site availability of graphene. The adsorption isotherm on graphene followed Langmuir model with a maximum adsorption capacity of 323 mg/g, which was higher than other reported carbonaceous adsorbents. The CIP adsorption was thermodynamically favourable on graphene and primarily occurred through π - π interaction, according to the FTIR spectroscopy. While the adsorption capacity of graphene decreased with increasing solution pH due to the speciation change of CIP, the adverse effects of ionic strength (0.01-0.5 mol L(-1)), presence of NOM (5 mg L⁻¹), and different water sources (river water or drinking water) were less significant on graphene than GAC. These results indicated that graphene can serve as an alternative adsorbent for CIP removal in commonly encountered field conditions, if proper separation and recovery is available in place.

  19. Adsorption of bovine serum albumin on amorphous carbon surfaces studied with dip pen nanolithography

    Science.gov (United States)

    Yadav, Pradeep K.; McKavanagh, Fiona; Maguire, Paul D.; Lemoine, Patrick

    2011-10-01

    This article reports the use of dip pen nanolithography (DPN) for the study of adsorption of bovine serum albumin (BSA) proteins on amorphous carbon surfaces; tetrahedral amorphous carbon (t-aC) and silicon doped hydrogenated amorphous carbon (a-C:H:Si). Contact angle study shows that the BSA proteins reduce the contact angle on both carbon materials. We also noticed that the drop volume dependence is consistent with a negative line tension, i.e. due to an attractive protein/surface interaction. The DPN technique was used to write short-spaced (100 nm) BSA line patterns on both samples. We found a line merging effect, stronger in the case of the a-C:H:Si material. We discuss possible contributions from tip blunting, scratching, cross-talk between lever torsion and bending and nano-shaving of the patterns. We conclude that the observed effect is caused in large measure by the diffusion of BSA proteins on the amorphous carbon surfaces. This interpretation of the result is consistent with the contact angle data and AFM force curve analysis indicating larger tip/surface adhesion and spreading for the a-C:H:Si material. We conclude by discussing the advantages and limitations of DPN lithography to study biomolecular adsorption in nanoscale wetting environments.

  20. Preparation, characterization and phenol adsorption capacity of activated carbons from African beech wood sawdust

    Directory of Open Access Journals (Sweden)

    N.T. Abdel-Ghani

    2016-05-01

    Full Text Available In the present study, different activated carbons were prepared from carbonized African beech wood sawdust by potassium hydroxide activation. The activated carbons were characterized by brunauer–emmett–teller, scanning electron microscope, fourier transform infrared spectroscopy, and thermogravimetric analyzer. The phenol adsorption capacity of the prepared carbons was evaluated. The different factors affecting phenol’s removal were studied including: contact time, solution pH and initial phenol concentration. The optimum phenol removal was obtained after a contact time of 300 min. and at an initial phenol solution pH 7. The maximum removal percentages were determined at 5mg/l initial phenol concentration as 79, 93, 94 and 98% for AC0, AC1, AC2 and AC3; respectively. The adsorption of phenol on African beech sawdust activated carbons was found to follow the Lagergren first order kinetics and the intraparticle diffusion mechanism gave a good fit to the experimental data. The isothermal models applied fitted the experimental data in the order: Langmuir> Dubinin–Radushkevich> Freundlich and Temkin.

  1. Effect of the both texture and electrical properties of activated carbon on the CO{sub 2} adsorption capacity

    Energy Technology Data Exchange (ETDEWEB)

    Djeridi, W. [Research Laboratory: Engineering Process and Industrial Systems, National school of Engineers of Gabes, University of Gabes, St Omar Ibn Elkhattab, 6029 Gabes (Tunisia); Chimistry laboratory of Provence, University Aix-Marseille I, II, III- CNRS, UMR 6264, Centre de Saint Jerome, 13397 Marseille (France); Ouederni, A. [Research Laboratory: Engineering Process and Industrial Systems, National school of Engineers of Gabes, University of Gabes, St Omar Ibn Elkhattab, 6029 Gabes (Tunisia); Mansour, N.Ben [National Nanotechnology Research Centre, KACST, Riyadh (Saudi Arabia); Llewellyn, P.L. [Chimistry laboratory of Provence, University Aix-Marseille I, II, III- CNRS, UMR 6264, Centre de Saint Jerome, 13397 Marseille (France); Alyamani, A. [National Nanotechnology Research Centre, KACST, Riyadh (Saudi Arabia); El Mir, L., E-mail: djeridiwahid@yahoo.fr [Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Gabes University, Faculty of Sciences in Gabes, Gabes (Tunisia); Al Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Department of Physics, 11623 Riyadh (Saudi Arabia)

    2016-01-15

    Highlights: • A series of activated carbon pellet without binder was prepared by chemical activation. • Carbon dioxide storage isotherm at 30 °C and up to 25 bars was measured for the microporous carbon. • Adsorption enthalpies have been correlated with the carbon dioxide uptake. • Pyrolysis temperature effect on the electrical conductivity of the samples. • Impact of the both texture and electrical properties on CO{sub 2} adsorption capacity have been deducted - Abstract: A series of activated carbon pellets (ACP) based on olive stones were studied for CO{sub 2} storage application. The surface area, pore volume, and pore diameter were evaluated from the analysis of N{sub 2} adsorption isotherm data. The characterization of carbon materials was performed by scanning electron microscopy (SEM), the powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM). The adsorption enthalpies were obtained by microcalorimetry. The effect of pyrolysis temperature on textural, electrical conductivity and gas adsorption capacities of the ACP were investigated by adsorbing CO{sub 2} at 303 K in the pressure range of 0–2.3 MPa. In fact the electrical conductivity is strongly affected by the microporosity of the samples and the size of the micropore. It increases when the pore size decreases which affect the CO{sub 2} adsorption. Also with increases temperature the free electrons concentration on the surface increases which affect the interaction of the adsorbed gas molecules.

  2. Adsorption of low concentration ceftazidime from aqueous solutions using impregnated activated carbon promoted by Iron, Copper and Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiang, E-mail: huxiang@mail.buct.edu.cn [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Research Centre for Environmental Pollution Control and Resource Reuse Engineering of Beijing City, Beijing 100029 (China); Zhang, Hua [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Research Centre for Environmental Pollution Control and Resource Reuse Engineering of Beijing City, Beijing 100029 (China); Sun, Zhirong, E-mail: zrsun@bjut.edu.cn [College of Environmental & Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

    2017-01-15

    Graphical abstract: The graphic abstract describes the research that we used modified activated carbons impregnated with iron nitrate, copper nitrate and aluminium nitrate to adsorb ceftazidime from aqueous solution. The surface functional groups of the modified activated carbons were different, and thus resulted in the big difference in the adsorption performance of the modified activated carbons. The theory and the experiments both showed the preferable adsorption of ceftazidime could be achieved on modified activated carbons. - Highlights: • Three modified activated carbons were prepared by impregnating metal nitrate. • Characteristics of the modified activated carbons were analyzed. • Adsorption capacity of ceftazidime on modified activated carbons was improved. • The adsorption behavior of ceftazidime on modified activated carbons were revealed. • The nature of ceftazidime adsorption on modified activated carbons was elucidated. - Abstract: In this paper, three impregnated activated carbon IAC (AC-Cu, AC-Fe, and AC-Al) promoted by Iron, Copper and Aluminum were used for adsorption of ceftazidime. Iron(III), Copper(II) and Aluminum(III) nitrate were used as an impregnant. The IACs were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) surface area analyzer, Fourier transform infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS).The influence of factors, such as ion strength, pH, temperature, initial concentration, and concentration of natural organic matter organic matter on the adsorption process were studied. The adsorption kinetics and isotherms of ceftazidime were studied for the three IACs. The results showed that the adsorption was accurately represented by pseudo-second order model. Under different temperature, the maximum adsorption quantity of ceftazidime on AC-Cu calculated by pseudo-second order kinetic model were 200.0 mg g{sup −1} (298 K), 196.1 mg g{sup −1} (303 K) and 185.2 mg g

  3. Kinetic modeling of liquid-phase adsorption of Congo red dye using guava leaf-based activated carbon

    Science.gov (United States)

    Ojedokun, Adedamola Titi; Bello, Olugbenga Solomon

    2017-07-01

    Guava leaf, a waste material, was treated and activated to prepare adsorbent. The adsorbent was characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infra Red (FTIR) and Energy-Dispersive X-ray (EDX) techniques. The carbonaceous adsorbent prepared from guava leaf had appreciable carbon content (86.84 %). The adsorption of Congo red dye onto guava leaf-based activated carbon (GLAC) was studied in this research. Experimental data were analyzed by four different model equations: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms and it was found to fit Freundlich equation most. Adsorption rate constants were determined using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion model equations. The results clearly showed that the adsorption of CR dye onto GLAC followed pseudo-second-order kinetic model. Intraparticle diffusion was involved in the adsorption process. The mean energy of adsorption calculated from D-R isotherm confirmed the involvement of physical adsorption. Thermodynamic parameters were obtained and it was found that the adsorption of CR dye onto GLAC was an exothermic and spontaneous process at the temperatures under investigation. The maximum adsorption of CR dye by GLAC was found to be 47.62 mg/g. The study shows that GLAC is an effective adsorbent for the adsorption of CR dye from aqueous solution.

  4. A study on hydrogen storage through adsorption in nano-structured carbons

    International Nuclear Information System (INIS)

    Langohr, D.

    2004-10-01

    The aim of this work is to build and calibrate an experimental set-up for the testing of the materials, to produce some carbon materials in large amounts and characterise them, and finally, to test these materials in their ability to store hydrogen. This will help in establishing a link between the hydrogen storage capacities of the carbons and their nano-structure. The script is divided into four chapters. The first chapter will deal with the literature review on the thematic of hydrogen storage through adsorption in the carbon materials, while the second chapter will present the experimental set-up elaborated in the laboratory. The third chapter explains the processes used to produce the two families of carbon materials and finally, the last chapter presents the structural characterisation of the samples as well as the experimental results of hydrogen storage on the materials elaborated. (author)

  5. Adsorption of Reactive Blue 171 from Aqueous Solution using Low Cost Activated Carbon Prepared from Agricultural Solid Waste: Albizia amara

    Directory of Open Access Journals (Sweden)

    K. Anitha

    2015-07-01

    Full Text Available The adsorption of Reactive Blue 171 (Reactive Dye from aqueous solution using activated carbon prepared from Albizia amara pod shell waste as an adsorbent have been carried out. The experimental adsorption data fitted reasonably well to Langmuir and Freundlich adsorption isotherms. Kinetic parameters as a function of Initial dye concentration have been calculated and the kinetic data were substituted in Pseudo First Order, Elovich and Pseudo Second order equations. A probable explanation is offered to account for the results of kinetic study. The thermodynamic parameter enthalpy change (∆H suggests the exothermic nature of absorption of Reactive Blue 171 onto activated Albizia amara pod shell waste carbon.

  6. Understanding carbon nanotube channel formation in the lipid membrane

    Science.gov (United States)

    Choi, Moon-ki; Kim, Hyunki; Lee, Byung Ho; Kim, Teayeop; Rho, Junsuk; Kim, Moon Ki; Kim, Kyunghoon

    2018-03-01

    Carbon nanotubes (CNTs) have been considered a prominent nano-channel in cell membranes because of their prominent ion-conductance and ion-selectivity, offering agents for a biomimetic channel platform. Using a coarse-grained molecular dynamics simulation, we clarify a construction mechanism of vertical CNT nano-channels in a lipid membrane for a long period, which has been difficult to observe in previous CNT-lipid interaction simulations. The result shows that both the lipid coating density and length of CNT affect the suitable fabrication condition for a vertical and stable CNT channel. Also, simulation elucidated that a lipid coating on the surface of the CNT prevents the CNT from burrowing into the lipid membrane and the vertical channel is stabilized by the repulsion force between the lipids in the coating and membrane. Our study provides an essential understanding of how CNTs can form stable and vertical channels in the membrane, which is important for designing new types of artificial channels as biosensors for bio-fluidic studies.

  7. The influence of iron oxide nanoparticles upon the adsorption of organic matter on magnetic powdered activated carbon.

    Science.gov (United States)

    Lompe, Kim Maren; Menard, David; Barbeau, Benoit

    2017-10-15

    Combining powdered activated carbon (PAC) with magnetic iron oxides has been proposed in the past to produce adsorbents for natural organic matter (NOM) removal that can be easily separated using a magnetic field. However, the trade-off between the iron oxides' benefits and the reduced carbon content, porosity, and surface area has not yet been investigated systematically. We produced 3 magnetic powdered activated carbons (MPAC) with mass fractions of 10%, 38% and 54% maghemite nanoparticles and compared them to bare PAC and pure nanoparticles with respect to NOM adsorption kinetics and isotherms. While adsorption kinetics were not influenced by the presence of the iron oxide nanoparticles (IONP), as shown by calculated diffusion coefficients from the homogeneous surface diffusion model, nanoparticles reduced the adsorption capacity of NOM due to their lower adsorption capacity. Although the nanoparticles added mesoporosity to the composite materials they blocked intrinsic PAC mesopores at mass fractions >38% as measured by N 2 -adsorption isotherms. Below this mass fraction, the adsorption capacity was mainly dependent on the carbon content in MPAC and mesopore blocking was negligible. If NOM adsorption with MPAC is desired, a highly mesoporous PAC and a low IONP mass fraction should be chosen during MPAC synthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Interpretation of single and competitive adsorption of cadmium and zinc on activated carbon using monolayer and exclusive extended monolayer models.

    Science.gov (United States)

    Sellaoui, Lotfi; Dotto, Guilherme L; Lamine, Abdelmottaleb Ben; Erto, Alessandro

    2017-08-01

    In this work, a modeling analysis based on experimental tests of cadmium/zinc adsorption, in both single-compound and binary systems, was carried out. All the experimental tests were conducted at constant pH (around neutrality) and temperature (20 °C). The experimental results showed that the zinc adsorption capacity was higher than that of cadmium and it does not depend on cadmium presence in binary system. Conversely, cadmium adsorption is affected by zinc presence. In order to provide good understanding of the adsorption process, two statistical physics models were proposed. A monolayer and exclusive extended monolayer models were applied to interpret the single-compound and binary adsorption isotherms of zinc and cadmium on activated carbon. Based on these models, the modeling analysis demonstrated that zinc is dominant in solution and more favorably adsorbed on activated carbon surface. For instance, in single-compound systems, the number of ions bound per each receptor site was n (Zn 2+ ) = 2.12 > n (Cd 2+ ) = 0.98. Thus, the receptor sites of activated carbon are more selective for Zn 2+ than for Cd 2+ . Moreover, the determination of adsorption energy through the adopted models confirmed that zinc is more favored for adsorption in single-compound system (adsorption energies equal to 12.12 and 7.12 kJ/mol for Zn and Cd, respectively) and its adsorption energy does not depend on the cadmium presence in binary system. Finally, the adsorption energy values suggested that single-compound and binary adsorption of zinc and cadmium is a physisorption.

  9. Adsorption and correlations of selected aromatic compounds on a KOH-activated carbon with large surface area.

    Science.gov (United States)

    Yang, Kun; Zhu, Lianghong; Yang, Jingjing; Lin, Daohui

    2018-03-15

    Knowledge of adsorption mechanism and behavior of organic compounds by KOH-activated carbons (KOH-ACs) from wastewater is crucial to its environmental application in wastewater treatment as adsorbent. A superior adsorbent, KOH-activated carbon (KOH-AC), with large surface area (3143m 2 /g), total pore volume of 2.03cm 3 /g, relatively low micropore fraction of 53.2%, and having adsorption capacities of organic compounds up to >1000mg/g, was prepared. It is an adsorbent significantly different with common ACs because the molecular sieving effect, widely observed for common ACs, is insignificant for KOH-AC. This difference could be attributed to the lower micropore fraction of KOH-AC than common ACs. A negative relationship of adsorption capacity of 25 aromatic compounds (including phenols, anilines, nitrobenzenes and polycyclic aromatic hydrocarbons) with chemical melting point was observed, suggesting that adsorption is dependent on the packing efficiency and stacking density of molecules on KOH-AC. A linear solvation energy relationships of adsorption affinity of 25 aromatic compounds with solute solvatochromic parameters was also observed, that can be used to quantify the contributions of π-π interaction, hydrogen-bonding interaction and hydrophobic effect to adsorption on KOH-AC. Combined with the reported results of adsorption of organic compounds on carbon nanotubes and biochars, it was also observed that external surface area of adsorbents is controlling the packing efficiency and stacking density of molecules on adsorbents and thus affecting adsorption capacity of organic compounds. Moreover, micropore surface area and the fraction of micropores are the adsorbent properties mainly affecting adsorption affinity of organic compounds. The observations and the developed correlations in this study would be helpful in the application of KOH-AC as superior adsorbent by enhancing the understanding of adsorption mechanisms of organic compounds on KOH-AC and by

  10. Electrostatic Adsorption of Platinum onto Carbon Nanotubes and Nanofibers for Nanoparticle Synthesis

    Directory of Open Access Journals (Sweden)

    Ritubarna Banerjee

    2018-02-01

    Full Text Available Strong Electrostatic Adsorption (SEA has been demonstrated as a simple, scientific method to prepare well dispersed Pt nanoparticles over typical forms of carbon: activated, black, and graphitic carbons. Many varieties of specialty carbons have been invented in the last few decades including multi-walled nanotubes, nanofibers, graphene nanoplatelets, etc. In this work, we explore whether SEA can be applied to these specialty carbons for the synthesis of Pt nanoparticles. Over a number of oxidized and unoxidized multiwalled nanotubes and nanofibers, the point of zero charge (PZC was measured and the uptake of anionic Pt complexes (Pt hexachloride, [PtCl6]2−, and cationic Pt complexes (platinum tetraammine, [Pt(NH34]2+ as functions of final pH were surveyed. Pt nanoparticles on the various supports were synthesized at the optimal pH and were characterized by x-ray diffraction (XRD and scanning transmission electron microscopy (STEM. The specialty carbons displayed volcano-shaped uptake curves typical of electrostatic adsorption for both Pt anions at low pH and Pt cations at high pH. However, the regimes of uptake often did not correspond to the measured PZC, probably due to surface impurities from the carbon manufacturing process. This renders the measured PZC of these specialty carbons unreliable for predicting anion and cation uptake. On the other hand, the anion and cation uptake curves provide an “effective” PZC and do indicate the optimal pH for the synthesis of ultrasmall nanoparticle synthesis. High resolution STEM imaging also showed that with SEA it is possible to disperse nanoparticles on the surface as well as the inner walls of the specialty carbons.

  11. Textural development and hydrogen adsorption of carbon materials from PET waste

    International Nuclear Information System (INIS)

    Parra, J.B.; Ania, C.O.; Arenillas, A.; Rubiera, F.; Palacios, J.M.; Pis, J.J.

    2004-01-01

    Polyethyleneterephthalate (PET) has become one of the major post-consumer plastic wastes. PET products present a problem of considerable concern due to the huge amount of solid waste produced. The disposal of this waste, together with its low bio- and photo-degradability represents a serious challenge for industrial countries all over the world. Pyrolysis could provide an alternative and economically viable route for processing PET waste due to the potential uses of different by-products: energy from the pyrolysis gases (58% yield in this work), recovery of terephthalic acid and other subproducts (20%), and a solid residue (22%), which has shown a high textural development after activation. The pyrolysis of PET waste was performed in a quartz reactor (i.d. 35 mm) under an inert atmosphere. Further activation was carried out at a temperature of 925 deg. C, with a flow rate of 10 ml min -1 of CO 2 . A series of carbon materials with different burn-off degrees was obtained. Textural characterisation of the samples was carried out by performing N 2 adsorption isotherms at -196 deg. C. Changes in the morphological and structural properties of chars were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The carbons obtained were isotropic and highly microporous materials with apparent BET surface areas of up to 2500 m 2 g -1 . The suitability of the samples for hydrogen storage was studied by performing H 2 adsorption measurements in the 0-1 bar pressure range. Adsorption-desorption experiments showed that reversible physisorption takes place in all the samples. The hydrogen adsorption capacities of the activated PET waste compare favourably well with those attained with high-value carbon materials

  12. Adsorption of diazinon from aqueous solutions onto an activated carbon sample produced in Iran

    Directory of Open Access Journals (Sweden)

    Zeynab Akbarlou

    2017-05-01

    Full Text Available Background: Considering the severe health and environmental hazards caused by the entry of diazinon toxin into water resources, its removal is very important. Given the high costs of imported adsorbents, this research attempted to evaluate, for the first time, the efficiency of Iranian activated carbon in removing diazinon from aqueous solutions. Methods: In this batch experimental study, the effects of contact time (5-90 minutes, adsorbent concentration (0.5-30 g/L, initial concentration of diazinon (5-50 mg/L, and pH (3-10 on the adsorption of diazinon onto the activated carbon were evaluated. Concentrations of diazinon were measured using a high pressure liquid chromatography (HPLC instrument. The specific surface area of the adsorbent was determined by BET and BJH methods. The experimental adsorption data was analyzed using Langmuir and Freundlich isotherm models. Pseudo first-order and pseudo second-order kinetics models were employed to determine kinetics. Moreover, data was analyzed using SPSS version 19, and Pearson correlation and analysis of variance (ANOVA tests were performed at a significance level of 0.05. Results: The optimum contact time, sorbent dose, and pH were 30 minutes, 10 g/L, and 5, respectively. The adsorbent could adsorb diazinon with a removal efficiency of 92.5% under optimum conditions (initial concentration: 20 mg/L. The experimental data was better described by the pseudo-second order kinetic and Langmuir isotherm. A maximum adsorption capacity of 71.4 mg/g was calculated by the Langmuir isotherm model. Conclusion: With respect to the high adsorption capacity of Iranian activated carbon, this sorbent can be considered an efficient adsorbent for the removal of diazinon from aqueous solutions.

  13. Adsorption of ethylene on graphitized thermal carbon black and in slit pores: a computer simulation study.

    Science.gov (United States)

    Do, D D; Do, H D

    2004-08-17

    In this paper, we studied vapor-liquid equilibria (VLE) and adsorption of ethylene on graphitized thermal carbon black and in slit pores whose walls are composed of graphene layers. Simple models of a one-center Lennard-Jones (LJ) potential and a two-center united atom (UA)-LJ potential are investigated to study the impact of the choice of potential models in the description of VLE and adsorption behavior. Here, we used a Monte Carlo simulation method with grand canonical Monte Carlo (GCMC) and Gibbs ensemble Monte Carlo ensembles. The one-center potential model cannot describe adequately the VLE over the practical range of temperature from the triple point to the critical point. On the other hand, the two-center potential model (Wick et al. J. Phys. Chem. B 2000, 104, 8008-8016) performs well in the description of VLE (saturated vapor and liquid densities and vapor pressure) over the wide range of temperature. This UA-LJ model is then used in the study of adsorption of ethylene on graphitized thermal carbon black and in slit pores. Agreement between the GCMC simulation results and the experimental data on graphitized thermal carbon black for moderate temperatures is excellent, demonstrating that the potential of the GCMC method and the proper choice of potential model are essential to investigate adsorption. For slit pores of various sizes, we have found that the behavior of ethylene exhibits a number of features that are not manifested in the study of spherical LJ particles. In particular, the singlet density distribution versus distance across the pore and the angle between the molecular axis and the z direction provide rich information about the way molecules arrange themselves when the pore width is varied. Such an arrangement has been found to be very sensitive to the pore width.

  14. Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature.

    Science.gov (United States)

    Qian, Jin; Shen, Mengmeng; Wang, Peifang; Wang, Chao; Li, Kun; Liu, Jingjing; Lu, Bianhe; Tian, Xin

    2017-09-01

    Powdered activated carbon (PAC), as an adsorbent, was applied to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Laboratory batch experiments were performed to investigate the influences of phosphate (P) competition, temperature, and pH for PFOS adsorption onto PAC. The results showed that higher temperature favored PFOS adsorption in single and binary systems. The kinetic data fitted very well to the pseudo second-order kinetic model. Thermodynamically, the endothermic enthalpy of the PFOS adsorption in single and binary systems were 125.07 and 21.25 kJ mol -1 , respectively. The entropy of the PFOS adsorption in single and binary systems were 0.479 and 0.092 kJ mol -1  K -1 , respectively. And the Gibbs constants were negative. These results indicated that the adsorption processes were spontaneous. The adsorption isotherms of PFOS agreed well with the Langmuir model. In the single system, PFOS adsorption decreased with increased pH value. The difference in the amount of PFOS adsorption between the single and binary systems increased at higher pH. Frustrated total internal reflection (FTIR) demonstrated that P competition increased the hydrophilicity of the PAC and the electrostatic repulsion between PFOS and PAC, then the PFOS adsorption amount decreased. It also demonstrated that, at higher temperature, increased PFOS adsorption was mainly due to the higher diffusion rate of PFOS molecules and greater number of active sites opened on the PAC surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Adsorption of Cu(II) on Oxidized Multi-Walled Carbon Nanotubes in the Presence of Hydroxylated and Carboxylated Fullerenes

    Science.gov (United States)

    Wang, Jing; Li, Zhan; Li, Shicheng; Qi, Wei; Liu, Peng; Liu, Fuqiang; Ye, Yuanlv; Wu, Liansheng; Wang, Lei; Wu, Wangsuo

    2013-01-01

    The adsorption of Cu(II) on oxidized multi-walled carbon nanotubes (oMWCNTs) as a function of contact time, pH, ionic strength, temperature, and hydroxylated fullerene (C60(OH)n) and carboxylated fullerene (C60(C(COOH)2)n) were studied under ambient conditions using batch techniques. The results showed that the adsorption of Cu(II) had rapidly reached equilibrium and the kinetic process was well described by a pseudo-second-order rate model. Cu(II) adsorption on oMWCNTs was dependent on pH but independent of ionic strength. Compared with the Freundlich model, the Langmuir model was more suitable for analyzing the adsorption isotherms. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that Cu(II) adsorption on oMWCNTs was spontaneous and endothermic. The effect of C60(OH)n on Cu(II) adsorption of oMWCNTs was not significant at low C60(OH)n concentration, whereas a negative effect was observed at higher concentration. The adsorption of Cu(II) on oMWCNTs was enhanced with increasing pH values at pH adsorption of Cu(II) onto oMWCNTs at pH 4–6. The double sorption site model was applied to simulate the adsorption isotherms of Cu(II) in the presence of C60(OH)n and fitted the experimental data well. PMID:24009683

  16. Effect of gas adsorption on acoustic wave propagation in MFI zeolite membrane materials: experiment and molecular simulation.

    Science.gov (United States)

    Manga, Etoungh D; Blasco, Hugues; Da-Costa, Philippe; Drobek, Martin; Ayral, André; Le Clezio, Emmanuel; Despaux, Gilles; Coasne, Benoit; Julbe, Anne

    2014-09-02

    The present study reports on the development of a characterization method of porous membrane materials which consists of considering their acoustic properties upon gas adsorption. Using acoustic microscopy experiments and atomistic molecular simulations for helium adsorbed in a silicalite-1 zeolite membrane layer, we showed that acoustic wave propagation could be used, in principle, for controlling the membranes operando. Molecular simulations, which were found to fit experimental data, showed that the compressional modulus of the composite system consisting of silicalite-1 with adsorbed He increases linearly with the He adsorbed amount while its shear modulus remains constant in a large range of applied pressures. These results suggest that the longitudinal and Rayleigh wave velocities (VL and VR) depend on the He adsorbed amount whereas the transverse wave velocity VT remains constant.

  17. Adsorption of Cd (II) on Modified Granular Activated Carbons: Isotherm and Column Study.

    Science.gov (United States)

    Rodríguez-Estupiñán, Paola; Erto, Alessandro; Giraldo, Liliana; Moreno-Piraján, Juan Carlos

    2017-12-20

    In this work, equilibrium and dynamic adsorption tests of cadmium Cd (II) on activated carbons derived from different oxidation treatments (with either HNO₃, H₂O₂, or NaOCl, corresponding to GACoxN, GACoxP, and GACoxCl samples) are presented. The oxidation treatments determined an increase in the surface functional groups (mainly the acidic ones) and a decrease in the pH PZC (except for the GACoxCl sample). A slight alteration of the textural parameters was also observed, which was more significant for the GACoxCl sample, in terms of a decrease of both Brunauer-Emmett-Teller ( BET ) surface area and micropore volume. Adsorption isotherms were determined for all the adsorbents and a significant increase in the adsorption performances of the oxidized samples with respect to the parent material was observed. The performances ranking was GACoxCl > GACoxP > GACoxN > GAC, likely due to the chemical surface properties of the adsorbents. Dynamic tests in a fixed bed column were carried out in terms of breakthrough curves at constant Cd inlet concentration and flow rate. GACoxCl and GACoxN showed a significantly higher value of the breakpoint time, likely due to the higher adsorption capacity. Finally, the dynamic tests were analyzed in light of a kinetic model. In the adopted experimental conditions, the results showed that mass transfer is controlled by internal pore diffusion, in which surface diffusion plays a major role.

  18. Adsorption of non-steroidal anti-inflammatory drugs from aqueous solution using activated carbons: Review.

    Science.gov (United States)

    Ahmed, Muthanna J

    2017-04-01

    Pharmaceutical pollutants are of significant effect on the environment, so that their treatments have been addressed in many studies. Activated carbon (AC) adsorbent shows best attraction for these compounds due to its unique characteristics represented by high capacity and porosity. In this article, the adsorption performance of AC towards non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, ketoprofen, naproxen, and diclofenac were reviewed. According to collected data, maximum adsorption capacities of 417, 25, 290, and 372 mg/g were obtained from Langmuir isotherm for these drugs, respectively. The values of 1/n for Freundlich isotherm were lower than unity for all studied drugs, confirming the nonlinear and favorable adsorption. In addition, kinetics data were well represented by the pseudo-second-order model and mechanism was not controlled by the pore diffusion step alone. AC adsorption demonstrated superior performance for all selected NSAIDs, thus being efficient technology for treatment of these pharmaceutical pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Effect of alignment on adsorption characteristics of self-oriented multi-walled carbon nanotube arrays

    International Nuclear Information System (INIS)

    Zilli, D; Bonelli, P R; Cukierman, A L

    2006-01-01

    The adsorption characteristics of self-oriented multi-walled carbon nanotube (MWCNT) arrays are examined from N 2 (-196 deg. C) adsorption measurements. The arrays were synthesized in a laboratory by in situ chemical vapour deposition of iron or cobalt phthalocyanines at 880 and 950 deg. C, under otherwise constant conditions, in an attempt to obtain different morphological structures. For both precursors, increasing the temperature leads to MWCNT arrays with lower Brunauer-Emmett-Teller (BET) surface area and total pore volume, though the effect is more pronounced for those arising from the iron-based compound. Despite this, precursor yields of individual nanotubes of larger diameter, higher BET area and total pore volume characterize the resulting arrays compared to those arising from cobalt phthalocyanine for the same temperatures. As evidenced by SEM and TEM images, the arrays synthesized from iron phthalocyanine at 880 deg. C show better vertical alignment and denser structures than those obtained from this compound at 950 deg. C, and also from cobalt phthalocyanine at both temperatures. Further ultrasonication of the arrays produced from the iron compound brings about a significant reduction in their adsorption capacity, attributable to the pronounced disarrangement of the resulting structures. The present results demonstrate that the alignment of MWCNT arrays plays a crucial role in their N 2 adsorption characteristics

  20. Adsorption of caffeine on mesoporous activated carbon fibers prepared from pineapple plant leaves.

    Science.gov (United States)

    Beltrame, Karla K; Cazetta, André L; de Souza, Patrícia S C; Spessato, Lucas; Silva, Taís L; Almeida, Vitor C

    2018-01-01

    The present work reports the preparation of activated carbon fibers (ACFs) from pineapple plant leaves, and its application on caffeine (CFN) removal from aqueous solution. The preparation procedure was carried out using the H 3 PO 4 as activating agent and slow pyrolysis under N 2 atmosphere. The characterization of materials was performed from the N 2 adsorption and desorption isotherms, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, Boehm titration and pH pzc method. ACFs showed high BET surface area value (S BET = 1031m 2 g -1 ), well-developed mesoporous structure (mesopore volume of 1.27cm³ g -1 ) and pores with average diameter (D M ) of 5.87nm. Additionally, ACFs showed features of fibrous material with predominance of acid groups on its surface. Adsorption studies indicated that the pseudo-second order kinetic and Langmuir isotherm models were that best fitted to the experimental data. The monolayer adsorption capacity was found to be 155.50mgg -1 . thermodynamic studies revealed that adsorption process is spontaneous, exothermic and occurs preferably via physisorption. The pineapple leaves are an efficient precursor for preparation of ACFs, which were successful applied as adsorbent material for removal of caffeine from the aqueous solutions. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Decolorization of industrial wastewater by ozonation followed by adsorption on activated carbon

    International Nuclear Information System (INIS)

    Konsowa, A.H.; Ossman, M.E.; Chen, Yongsheng; Crittenden, John C.

    2010-01-01

    The decolorization of industrial wastewater containing direct dye (Drimarene Red CL-3B) by advanced oxidation process using ozonation in a semi-batch bubble column reactor followed by granule activated carbon (GAC) adsorption process was studied. The effect of initial dye concentration, ozone concentration, pH and ozone-air flow rate on the rate of dye decolorization were investigated. It was found that the rate of dye decolorization increases with increasing ozone concentration, ozone-air flow rate, and pH but decreases with increasing initial dye concentration. This study is a hybrid system conducted in combination between ozonation process and GAC adsorption to reveal higher and efficient removal of color and TOC. The process started with ozonation for efficient and rapid decolorization of dyeing wastewater, followed by GAC adsorption process to gain efficient removal of color and TOC. The adsorption process was found to be very efficient in removal of ozonation residual TOC, in view of high TOC removal, up to 37% TOC removal was obtained. Numerical correlation using regression analysis for decolorization time with the operating conditions of the ozonation process were presented.

  2. Modeling of the adsorption kinetics of zinc onto granular activated carbon and natural zeolite

    Directory of Open Access Journals (Sweden)

    VERA D. MESHKO

    2006-09-01

    Full Text Available The isotherms and kinetics of zinc adsorption from aqueous solution onto granular activated carbon (GAC and natural zeolite were studied using an agitated batch adsorber. The maximum adsorption capacities of GAC and natural zeolite towards zinc(II from Langmuir adsorption isotherms were determined using experimental adsorption equilibrium data. The homogeneous solid diffusion model (HSD-model combined with external mass transfer resistance was applied to fit the experimental kinetic data. The kinetics simulation study was performed using a computer program based on the proposed mathematical model and developed using gPROMS. As the two-mass transfer resistance approach was applied, twomodel parameters were fitted during the simulation study. External mass transfer and solid phase diffusion coefficients were obtained to predict the kinetic curves for varying initial Zn(II concentration at constant agitation speed and constant adsorbent mass. For any particular Zn(II – adsorbent system, kf was constant, except for the lowest initial concentration, while Ds was found to increase with increasing initial Zn(II concentration.

  3. Equilibrium and kinetic studies on free cyanide adsorption from aqueous solution by activated carbon.

    Science.gov (United States)

    Behnamfard, Ali; Salarirad, Mohammad Mehdi

    2009-10-15

    Adsorption equilibrium and kinetics of free cyanide onto activated carbon were investigated in the batch tests, and the effects of contact time (1-72 h) and initial cyanide concentrations in the range of 102-532 mg/L were studied. Linear regression was used to determine the best fit of equilibrium and kinetics expressions. The two-parameter models including Freundlich, Dubinin-Radushkevich, Temkin and four different linearized forms of Langmuir and three-parameter models including Redlich-Peterson and Koble-Corrigan were employed for fitting the equilibrium data and it was found that, three-parameter models fitted the data better than the two-parameter models and among the three-parameter models the equilibrium data are best represented by Koble-Corrigan model. A number of kinetic models including fractional power, zero order, first order, pseudo-first order, Elovich, second order, intraparticle diffusion and four different linearized forms of pseudo-second order models were tested to fit the kinetic data. The latter was found to be consistent with the data. Intraparticle diffusion plots show that the adsorption process of free cyanide is a two steps process. In the first step, the adsorption of cyanide is fast while in the second step, cyanide adsorption slows down.

  4. Tetracycline adsorption onto activated carbons produced by KOH activation of tyre pyrolysis char.

    Science.gov (United States)

    Acosta, R; Fierro, V; Martinez de Yuso, A; Nabarlatz, D; Celzard, A

    2016-04-01

    Tyre pyrolysis char (TPC), produced when manufacturing pyrolysis oil from waste tyre, was used as raw material to prepare activated carbons (ACs) by KOH activation. KOH to TPC weight ratios (W) between 0.5 and 6, and activation temperatures from 600 to 800 °C, were used. An increase in W resulted in a more efficient development of surface area, microporosity and mesoporosity. Thus, ACs derived from TPC (TPC-ACs) with specific surface areas up to 814 m(2) g(-1) were obtained. TPC, TPC-ACs and a commercial AC (CAC) were tested for removing Tetracycline (TC) in aqueous phase, and systematic adsorption studies, including equilibrium, kinetics and thermodynamic aspects, were performed. Kinetics was well described by the pseudo-first order model for TPC, and by a pseudo second-order kinetic model for ACs. TC adsorption equilibrium data were also fitted by different isotherm models: Langmuir, Freundlich, Sips, Dubinin-Radushkevich, Dubinin-Astokov, Temkin, Redlich-Peterson, Radke-Prausnitz and Toth. The thermodynamic study confirmed that TC adsorption onto TPC-ACs is a spontaneous process. TC adsorption data obtained in the present study were compared with those reported in the literature, and differences were explained in terms of textural properties and surface functionalities. TPC-ACs had similar performances to those of commercial ACs, and might significantly improve the economic balance of the production of pyrolysis oil from waste tyres. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Transport phenomena of electrons at the carbon nanotube interface with molecular adsorption

    Science.gov (United States)

    Kokabu, Takuya; Takashima, Kengo; Inoue, Shuhei; Matsumura, Yukihiko; Yamamoto, Takahiro

    2017-07-01

    The electric conductance of carbon-nanotube (CNT) films is affected by gas adsorption. Previous studies have shown that the adsorption of gas molecules on the CNT/CNT interface is the key to the changing CNT-film conductance. However, it is still unclear how the gas molecules affect the electric conduction of the CNT/CNT interface or its electron transport properties. We present here a study on the effects of gas-molecule adsorption on the CNT/CNT interface using a fluctuation-induced tunneling (FIT) model of the CNT-film electrical conduction. We demonstrated that the CNT-film conduction follows the FIT model, and the subsequently estimated electrostatic potential between the CNT/CNT interfaces was in good agreement with estimates from density functional theory simulations. Since the FIT model treats the CNT/CNT interface as a parallel-plate capacitor, we propose a modified FIT model that accounts for the change in the dielectric constant at the CNT/CNT interface due to the adsorption of gas molecules. This model well explained the electric-conductance change of the CNT film with respect to the gas pressure. Finally, we found that the adsorbed gas molecules affected the local dielectric constant at the CNT/CNT interface.

  6. Predicting adsorption of aromatic compounds by carbon nanotubes based on quantitative structure property relationship principles

    Science.gov (United States)

    Rahimi-Nasrabadi, Mehdi; Akhoondi, Reza; Pourmortazavi, Seied Mahdi; Ahmadi, Farhad

    2015-11-01

    Quantitative structure property relationship (QSPR) models were developed to predict the adsorption of aromatic compounds by carbon nanotubes (CNTs). Five descriptors chosen by combining self-organizing map and stepwise multiple linear regression (MLR) techniques were used to connect the structure of the studied chemicals with their adsorption descriptor (K∞) using linear and nonlinear modeling techniques. Correlation coefficient (R2) of 0.99 and root-mean square error (RMSE) of 0.29 for multilayered perceptron neural network (MLP-NN) model are signs of the superiority of the developed nonlinear model over MLR model with R2 of 0.93 and RMSE of 0.36. The results of cross-validation test showed the reliability of MLP-NN to predict the K∞ values for the aromatic contaminants. Molar volume and hydrogen bond accepting ability were found to be the factors much influencing the adsorption of the compounds. The developed QSPR, as a neural network based model, could be used to predict the adsorption of organic compounds by CNTs.

  7. Effect of alignment on adsorption characteristics of self-oriented multi-walled carbon nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Zilli, D [Programa de Investigacion y Desarrollo de Fuentes Alternativas de Materias Primas y EnergIa (PINMATE)-Depto. de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Gueiraldes 2620, Ciudad Universitaria (C1428BGA), Buenos Aires (Argentina); Bonelli, P R [Programa de Investigacion y Desarrollo de Fuentes Alternativas de Materias Primas y EnergIa (PINMATE)-Depto. de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Gueiraldes 2620, Ciudad Universitaria (C1428BGA), Buenos Aires (Argentina); Cukierman, A L [Programa de Investigacion y Desarrollo de Fuentes Alternativas de Materias Primas y EnergIa (PINMATE)-Depto. de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Gueiraldes 2620, Ciudad Universitaria (C1428BGA), Buenos Aires (Argentina)

    2006-10-28

    The adsorption characteristics of self-oriented multi-walled carbon nanotube (MWCNT) arrays are examined from N{sub 2} (-196 deg. C) adsorption measurements. The arrays were synthesized in a laboratory by in situ chemical vapour deposition of iron or cobalt phthalocyanines at 880 and 950 deg. C, under otherwise constant conditions, in an attempt to obtain different morphological structures. For both precursors, increasing the temperature leads to MWCNT arrays with lower Brunauer-Emmett-Teller (BET) surface area and total pore volume, though the effect is more pronounced for those arising from the iron-based compound. Despite this, precursor yields of individual nanotubes of larger diameter, higher BET area and total pore volume characterize the resulting arrays compared to those arising from cobalt phthalocyanine for the same temperatures. As evidenced by SEM and TEM images, the arrays synthesized from iron phthalocyanine at 880 deg. C show better vertical alignment and denser structures than those obtained from this compound at 950 deg. C, and also from cobalt phthalocyanine at both temperatures. Further ultrasonication of the arrays produced from the iron compound brings about a significant reduction in their adsorption capacity, attributable to the pronounced disarrangement of the resulting structures. The present results demonstrate that the alignment of MWCNT arrays plays a crucial role in their N{sub 2} adsorption characteristics.

  8. Carbon-coated Zinc Sulfide nano-clusters: synthesis, photothermal conversion and adsorption properties.

    Science.gov (United States)

    Bao, Chunlin; Zhu, Guoxing; Shen, Mengqi; Yang, Jing

    2014-12-15

    Carbon-coated cluster-like ZnS nanospheres were synthesized by a facile solvothermal route. ZnCl2, thiourea, and glucose were selected as the raw materials. The formed ZnS with hexagonal phase has spherical cluster-like structure, which shows good monodispersity in size. A thin layer carbon is coated on the surface of ZnS cluster-like spheres. The thickness of carbon shell is dependent on the dosage of glucose. The carbon-coated ZnS nano-clusters show the same emission as that of pristine ZnS nano-clusters. Exposure of the aqueous dispersion of carbon-coated ZnS products to 980 nm laser can elevate its temperature by 5.1°C in 8 min. It was found that the photothermal conversion effect mainly comes from the carbon component and at the same time, the heterointerface between ZnS and carbon also provides a positive role for it. In addition, the carbon-coated ZnS products can absorb dye molecular with highest adsorption capacity of 36.8 mg/g toward Rhodamine B. The present finding demonstrates their potential applications in photothermal agents, adsorbents, and related fields. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Adsorption equilibrium and thermodynamics of CO2 and CH4 on carbon molecular sieves

    Science.gov (United States)

    Song, Xue; Wang, Li'ao; Ma, Xu; Zeng, Yunmin

    2017-02-01

    Carbon molecular sieves (CMS) are widely used in the separation of dioxide carbon and methane. In this research, three commercial CMS were utilized to analyze the pore structure and chemical properties. The adsorption isotherms of CO2 and CH4 were studied at 298 K, 308 K and 318 K over the pressure range of 0-1 MPa by an Intelligent Gravimetric analysis (IGA-100B, UK). Langmuir model was adopted to fit the experimental data. The working capacity and selectivity were employed to evaluate the adsorbents. The adsorption thermodynamics were discussed. The adsorbed amounts of both CO2 and CH4 are found to be highly related with the BET specific surface area and the volume of micropores, and also are interrelated with the total pore volume and micropore surface area. The standard enthalpy change (ΔHΘ), standard Gibbs free energy (ΔGΘ) and standard entropy change (ΔSΘ) at zero surface loading are negative, manifesting the adsorption process is exothermic and spontaneous, and the system tends to be ordered. With the increasing surface coverage, the absolute values of Gibbs free energy (ΔG) decrease whereas the absolute values of enthalpy change (ΔH) and entropy change(ΔS) increase. This indicates that as the adsorbed amount increases, the degree of the spontaneity reduces, the intermolecular forces among the adsorbate molecules increase, the orderliness of the system improves and the adsorbed amount approaches the maximum adsorbed capacity.

  10. Kinetics, Equilibrium, and Thermodynamic Studies on Adsorption of Methylene Blue by Carbonized Plant Leaf Powder

    Directory of Open Access Journals (Sweden)

    V. Gunasekar

    2013-01-01

    Full Text Available Carbon synthesized from plant leaf powder was employed for the adsorption of methylene blue from aqueous effluent. Effects of pH (2, 4, 6, 8, and 9, dye concentration (50, 100, 150, and 200 mg/dm3, adsorbent dosage (0.5, 1.0, 1.5, and 2.0 g/dm3, and temperature (303, 313, and 323 K were studied. The process followed pseudo-second-order kinetics. Equilibrium data was examined with Langmuir and Freundlich isotherm models and Langmuir model was found to be the best fitting model with high R2 and low chi2 values. Langmuir monolayer adsorption capacity of the adsorbent was found to be 61.22 mg/g. From the thermodynamic analysis, ΔH, ΔG, and ΔS values for the adsorption of MB onto the plant leaf carbon were found out. From the values of free energy change, the process was found out to be feasible process. From the magnitude of ΔH, the process was found to be endothermic physisorption.

  11. Adsorption of NI (II on activated Carbon of Coconut shell Chemicaly Modifieded with Acid Nitric Solutions

    Directory of Open Access Journals (Sweden)

    Mónica Hernández-Rodríguez

    2017-01-01

    Full Text Available In the research the effect of modification of coconut shell activated carbon with diluted solutions of nitric acid, in its chemical characteristics and removal capacity of the nickel (II ions present in modeling solutions of sulfates with similar characteristics to the acid liquor waste of the nickel industry, was studied. The characterization of the adsorbent material evidenced that the modification process increases the superficial acids groups according with the increase of acid nitric concentration employee in the treatment. The adsorption equilibrium tests, carried out with metallic species solutions at concentrations between 0,5 and 3,5 g/L evidenced that the process is described by Freundlich model. The effect of chemical modification of the adsorbent material in adsorption capacity of nickel (II ions was evaluated using a traditional experimental design at pH of 1,2 and 6,9 units, obtaining that the increase of acid groups in the carbon surface causes an increase of adsorption capacity and removal percentages of nickel (II, due to specific interactions of these groups with the metal cations.

  12. Thermodynamics of carbon dioxide adsorption on the protonic zeolite H-ZSM-5.

    Science.gov (United States)

    Armandi, Marco; Garrone, Edoardo; Areán, Carlos O; Bonelli, Barbara

    2009-12-21

    Adsorption of carbon dioxide on H-ZSM-5 zeolite (Si:Al=11.5:1) was studied by means of variable-temperature FT-IR spectroscopy, in the temperature range of 310-365 K. The adsorbed CO(2) molecules interact with the zeolite Brønsted-acid OH groups bringing about a characteristic red-shift of the O-H stretching band from 3610 cm(-1) to 3480 cm(-1). Simultaneously, the nu(3) mode of adsorbed CO(2) is observed at 2345 cm(-1). From the variation of integrated intensity of the IR absorption bands at both 3610 and 2345 cm(-1), upon changing temperature (and CO(2) equilibrium pressure), the standard adsorption enthalpy of CO(2) on H-ZSM-5 is DeltaH(0)=-31.2(+/-1) kJ mol(-1) and the corresponding entropy change is DeltaS(0)=-140(+/-10) J mol(-1) K(-1). These results are discussed in the context of available data for carbon dioxide adsorption on other protonic, and also alkali-metal exchanged, zeolites.

  13. Tunable integration of absorption-membrane-adsorption for efficiently separating low boiling gas mixtures near normal temperature.

    Science.gov (United States)

    Liu, Huang; Pan, Yong; Liu, Bei; Sun, Changyu; Guo, Ping; Gao, Xueteng; Yang, Lanying; Ma, Qinglan; Chen, Guangjin

    2016-02-19

    Separation of low boiling gas mixtures is widely concerned in process industries. Now their separations heavily rely upon energy-intensive cryogenic processes. Here, we report a pseudo-absorption process for separating low boiling gas mixtures near normal temperature. In this process, absorption-membrane-adsorption is integrated by suspending suitable porous ZIF material in suitable solvent and forming selectively permeable liquid membrane around ZIF particles. Green solvents like water and glycol were used to form ZIF-8 slurry and tune the permeability of liquid membrane surrounding ZIF-8 particles. We found glycol molecules form tighter membrane while water molecules form looser membrane because of the hydrophobicity of ZIF-8. When using mixing solvents composed of glycol and water, the permeability of liquid membrane becomes tunable. It is shown that ZIF-8/water slurry always manifests remarkable higher separation selectivity than solid ZIF-8 and it could be tuned to further enhance the capture of light hydrocarbons by adding suitable quantity of glycol to water. Because of its lower viscosity and higher sorption/desorption rate, tunable ZIF-8/water-glycol slurry could be readily used as liquid absorbent to separate different kinds of low boiling gas mixtures by applying a multistage separation process in one traditional absorption tower, especially for the capture of light hydrocarbons.

  14. Tunable integration of absorption-membrane-adsorption for efficiently separating low boiling gas mixtures near normal temperature

    Science.gov (United States)

    Liu, Huang; Pan, Yong; Liu, Bei; Sun, Changyu; Guo, Ping; Gao, Xueteng; Yang, Lanying; Ma, Qinglan; Chen, Guangjin

    2016-01-01

    Separation of low boiling gas mixtures is widely concerned in process industries. Now their separations heavily rely upon energy-intensive cryogenic processes. Here, we report a pseudo-absorption process for separating low boiling gas mixtures near normal temperature. In this process, absorption-membrane-adsorption is integrated by suspending suitable porous ZIF material in suitable solvent and forming selectively permeable liquid membrane around ZIF particles. Green solvents like water and glycol were used to form ZIF-8 slurry and tune the permeability of liquid membrane surrounding ZIF-8 particles. We found glycol molecules form tighter membrane while water molecules form looser membrane because of the hydrophobicity of ZIF-8. When using mixing solvents composed of glycol and water, the permeability of liquid membrane becomes tunable. It is shown that ZIF-8/water slurry always manifests remarkable higher separation selectivity than solid ZIF-8 and it could be tuned to further enhance the capture of light hydrocarbons by adding suitable quantity of glycol to water. Because of its lower viscosity and higher sorption/desorption rate, tunable ZIF-8/water-glycol slurry could be readily used as liquid absorbent to separate different kinds of low boiling gas mixtures by applying a multistage separation process in one traditional absorption tower, especially for the capture of light hydrocarbons. PMID:26892255

  15. Synthesis and characterization of Ag nanoparticles decorated mesoporous sintered activated carbon with antibacterial and adsorptive properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenxia; Xiao, Kaijun, E-mail: fekjxiao@scut.edu.cn; He, Tinglin; Zhu, Liang, E-mail: zhuliang@scut.edu.cn

    2015-10-25

    In this study, the sliver nanoparticles (AgNPs) immobilized on the sintered activated carbon (Ag/SAC) were synthesized by the ultrasonic-assisted impregnation method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption. SEM showed that the AgNPs were well embedded in the SAC and immersion time had an important influence on final morphologies of AgNPs. Longer immersing duration caused significant aggregation of the AgNPs. The XRD data revealed that the successful synthesis of AgNPs on the SAC and immobilizing AgNPs on sintered active carbon did not change the crystalline degree of SAC. Texture characteristics were determined by analysis of the N{sub 2}/77 K isotherms. The minimum inhibitory concentration (MIC) of Ag/SAC against Escherichia coli (DH5α) and Staphyloccocus aureus (ATCC 29213) was evaluated by a broth dilution method. MICs such as 5 mg/L (against E. coli) and 10 mg/L (against S. aureus) suggest that Ag/SAC have predominant antibacterial activity compared to active carbon. - Highlights: • Sintered active carbon (SAC) was coated with Ag via a facile approach. • The Ag/SAC exhibit good adsorption properties and excellent antibacterial effects. • The Ag/SAC was durable and stable in the application of water purification.

  16. Synthesis and characterization of Ag nanoparticles decorated mesoporous sintered activated carbon with antibacterial and adsorptive properties

    International Nuclear Information System (INIS)

    Wang, Wenxia; Xiao, Kaijun; He, Tinglin; Zhu, Liang

    2015-01-01

    In this study, the sliver nanoparticles (AgNPs) immobilized on the sintered activated carbon (Ag/SAC) were synthesized by the ultrasonic-assisted impregnation method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption. SEM showed that the AgNPs were well embedded in the SAC and immersion time had an important influence on final morphologies of AgNPs. Longer immersing duration caused significant aggregation of the AgNPs. The XRD data revealed that the successful synthesis of AgNPs on the SAC and immobilizing AgNPs on sintered active carbon did not change the crystalline degree of SAC. Texture characteristics were determined by analysis of the N 2 /77 K isotherms. The minimum inhibitory concentration (MIC) of Ag/SAC against Escherichia coli (DH5α) and Staphyloccocus aureus (ATCC 29213) was evaluated by a broth dilution method. MICs such as 5 mg/L (against E. coli) and 10 mg/L (against S. aureus) suggest that Ag/SAC have predominant antibacterial activity compared to active carbon. - Highlights: • Sintered active carbon (SAC) was coated with Ag via a facile approach. • The Ag/SAC exhibit good adsorption properties and excellent antibacterial effects. • The Ag/SAC was durable and stable in the application of water purification

  17. Manipulating Adsorption-Insertion Mechanisms in Nanostructured Carbon Materials for High-Efficiency Sodium Ion Storage

    Energy Technology Data Exchange (ETDEWE