Cell migration in microengineered tumor environments.

PubMed

Um, Eujin; Oh, Jung Min; Granick, Steve; Cho, Yoon-Kyoung

2017-12-05

Recent advances in microengineered cell migration platforms are discussed critically with a focus on how cell migration is influenced by engineered tumor microenvironments, the medical relevance being to understand how tumor microenvironments may promote or suppress the progression of cancer. We first introduce key findings in cancer cell migration under the influence of the physical environment, which is systematically controlled by microengineering technology, followed by multi-cues of physico-chemical factors, which represent the complexity of the tumor environment. Recognizing that cancer cells constantly communicate not only with each other but also with tumor-associated cells such as vascular, fibroblast, and immune cells, and also with non-cellular components, it follows that cell motility in tumor microenvironments, especially metastasis via the invasion of cancer cells into the extracellular matrix and other tissues, is closely related to the malignancy of cancer-related mortality. Medical relevance of forefront research realized in microfabricated devices, such as single cell sorting based on the analysis of cell migration behavior, may assist personalized theragnostics based on the cell migration phenotype. Furthermore, we urge development of theory and numerical understanding of single or collective cell migration in microengineered platforms to gain new insights in cancer metastasis and in therapeutic strategies.

Microengineered open tubular columns for GC analysis

NASA Astrophysics Data System (ADS)

Wiranto, Goib; Haskard, Malcolm R.; Mulcahy, Dennis E.; Davey, David E.; Dawes, Ernest F.

1999-09-01

Microengineered open tubular (MOT) columns with semi rectangular cross-sections have been designed and fabricated using microengineering techniques. The creation of 100-micrometers wide, 20-micrometers deep, and 125-cm long columns employed isotropic etching on (100) silicon and anodic bonding with a Pyrex 7740 glass cover plate. Column geometry has been optimized to achieve maximum efficiency and allow extreme operating conditions. The walls of the microcolumns were coated with a non-polar liquid stationary phase. Performances of the MOT columns have been demonstrated by their ability to completely separate a series of hydrocarbon mixture in less than 1.25 min under isothermal condition of 150 degrees C. The achievable column efficiencies as measured in terms of theoretical plate height ranged from 0.57 to 1.45 mm, which agreed well with theoretical predictions.

Ultrasound-modulated bubble propulsion of chemically powered microengines.

PubMed

Xu, Tailin; Soto, Fernando; Gao, Wei; Garcia-Gradilla, Victor; Li, Jinxing; Zhang, Xueji; Wang, Joseph

2014-06-18

The use of an ultrasound (US) field for rapid and reversible control of the movement of bubble-propelled chemically powered PEDOT/Ni/Pt microengines is demonstrated. Such operation reflects the US-induced disruption of normal bubble evolution and ejection, essential for efficient propulsion of catalytic microtubular engines. It offers precise speed control, with sharp increases and decreases of the speed at low and high US powers, respectively. A wide range of speeds can thus be generated by tuning the US power. Extremely fast changes in the motor speed (<0.1 s) and reproducible "On/Off" activations are observed, indicating distinct advantages compared to motion control methods based on other external stimuli. Such effective control of the propulsion of chemically powered microengines, including remarkable "braking" ability, holds considerable promise for diverse applications.

Demonstrating Optothermal Actuators for an Autonomous Mems Microrobot

DTIC Science & Technology

2004-03-01

of Toggled Microthermal Actuators,” Journal of Micromechanics and Microengineering, Vol. 14, pp 49-56, 2004. [10] S. Baglio, S. Castorina, L...127-132, 2000. [8] Y. Lai, J. McDonald, M. Kujath and T. Hubbard, “Force, Deflection and Power Measurements of Toggled Microthermal Actuators...Hubbard, "Force, Deflection and Power Measurements of Toggled Microthermal Actuators", Journal of Micromechanics and Microengineering, Vol. 14, pp 49

Micro-engineered first wall tungsten armor for high average power laser fusion energy systems

NASA Astrophysics Data System (ADS)

Sharafat, Shahram; Ghoniem, Nasr M.; Anderson, Michael; Williams, Brian; Blanchard, Jake; Snead, Lance; HAPL Team

2005-12-01

The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical survivability of the armor against the effects of high temperature pulsed operation and exfoliation due to the retention of implanted helium. Even if a solid tungsten armor coating would survive the high temperature cyclic operation with minimal failure, the high helium implantation and retention would result in unacceptable material loss rates. Micro-engineered materials, such as castellated structures, plasma sprayed nano-porous coatings and refractory foams are suggested as a first wall armor material to address these fundamental concerns. A micro-engineered FW armor would have to be designed with specific geometric features that tolerate high cyclic heating loads and recycle most of the implanted helium without any significant failure. Micro-engineered materials are briefly reviewed. In particular, plasma-sprayed nano-porous tungsten and tungsten foams are assessed for their potential to accommodate inertial fusion specific loads. Tests show that nano-porous plasma spray coatings can be manufactured with high permeability to helium gas, while retaining relatively high thermal conductivities. Tungsten foams where shown to be able to overcome thermo-mechanical loads by cell rotation and deformation. Helium implantation tests have shown, that pulsed implantation and heating releases significant levels of implanted helium. Helium implantation and release from tungsten was modeled using an expanded kinetic rate theory, to include the effects of pulsed implantations and thermal cycles. Although, significant challenges remain micro-engineered materials are shown to constitute potential candidate FW armor materials.

Microfluidic Organ/Body-on-a-Chip Devices at the Convergence of Biology and Microengineering.

PubMed

Perestrelo, Ana Rubina; Águas, Ana C P; Rainer, Alberto; Forte, Giancarlo

2015-12-10

Recent advances in biomedical technologies are mostly related to the convergence of biology with microengineering. For instance, microfluidic devices are now commonly found in most research centers, clinics and hospitals, contributing to more accurate studies and therapies as powerful tools for drug delivery, monitoring of specific analytes, and medical diagnostics. Most remarkably, integration of cellularized constructs within microengineered platforms has enabled the recapitulation of the physiological and pathological conditions of complex tissues and organs. The so-called "organ-on-a-chip" technology, which represents a new avenue in the field of advanced in vitro models, with the potential to revolutionize current approaches to drug screening and toxicology studies. This review aims to highlight recent advances of microfluidic-based devices towards a body-on-a-chip concept, exploring their technology and broad applications in the biomedical field.

Microfluidic Organ/Body-on-a-Chip Devices at the Convergence of Biology and Microengineering

PubMed Central

Perestrelo, Ana Rubina; Águas, Ana C. P.; Rainer, Alberto; Forte, Giancarlo

2015-01-01

Recent advances in biomedical technologies are mostly related to the convergence of biology with microengineering. For instance, microfluidic devices are now commonly found in most research centers, clinics and hospitals, contributing to more accurate studies and therapies as powerful tools for drug delivery, monitoring of specific analytes, and medical diagnostics. Most remarkably, integration of cellularized constructs within microengineered platforms has enabled the recapitulation of the physiological and pathological conditions of complex tissues and organs. The so-called “organ-on-a-chip” technology, which represents a new avenue in the field of advanced in vitro models, with the potential to revolutionize current approaches to drug screening and toxicology studies. This review aims to highlight recent advances of microfluidic-based devices towards a body-on-a-chip concept, exploring their technology and broad applications in the biomedical field. PMID:26690442

Microengineering Laser Plasma Interactions at Relativistic Intensities.

PubMed

Jiang, S; Ji, L L; Audesirk, H; George, K M; Snyder, J; Krygier, A; Poole, P; Willis, C; Daskalova, R; Chowdhury, E; Lewis, N S; Schumacher, D W; Pukhov, A; Freeman, R R; Akli, K U

2016-02-26

We report on the first successful proof-of-principle experiment to manipulate laser-matter interactions on microscales using highly ordered Si microwire arrays. The interaction of a high-contrast short-pulse laser with a flat target via periodic Si microwires yields a substantial enhancement in both the total and cutoff energies of the produced electron beam. The self-generated electric and magnetic fields behave as an electromagnetic lens that confines and guides electrons between the microwires as they acquire relativistic energies via direct laser acceleration.

Microengineering Laser Plasma Interactions at Relativistic Intensities

NASA Astrophysics Data System (ADS)

Jiang, S.; Ji, L. L.; Audesirk, H.; George, K. M.; Snyder, J.; Krygier, A.; Poole, P.; Willis, C.; Daskalova, R.; Chowdhury, E.; Lewis, N. S.; Schumacher, D. W.; Pukhov, A.; Freeman, R. R.; Akli, K. U.

2016-02-01

We report on the first successful proof-of-principle experiment to manipulate laser-matter interactions on microscales using highly ordered Si microwire arrays. The interaction of a high-contrast short-pulse laser with a flat target via periodic Si microwires yields a substantial enhancement in both the total and cutoff energies of the produced electron beam. The self-generated electric and magnetic fields behave as an electromagnetic lens that confines and guides electrons between the microwires as they acquire relativistic energies via direct laser acceleration.

Microengineering hydrogels for stem cell bioengineering and tissue regeneration.

PubMed

Wheeldon, Ian; Ahari, Amirhossein F; Khademhosseini, Ali

2010-12-01

The integration of microfabrication technologies with advanced biomaterials has led to the development of powerful tools to control the cellular microenvironment and the microarchitecture of engineered tissue constructs. Here we review this area, with a focus on the work accomplished in our laboratory. In particular, we discuss techniques to develop hydrogel microstructures for controlling cell aggregate formation to regulate stem cell behavior as well as a bottom-up and a top-down microengineering approach to creating biomimic tissue-like structures.

Microengineering hydrogels for stem cell bioengineering and tissue regeneration

PubMed Central

Wheeldon, Ian; Ahari, Amirhossein F.; Khademhosseini, Ali

2010-01-01

The integration of microfabrication technologies with advanced biomaterials has led to the development of powerful tools to control the cellular microenvironment and the microarchitecture of engineered tissue constructs. Here we review this area, with a focus on the work accomplished in our laboratory. In particular, we discuss techniques to develop hydrogel microstructures for controlling cell aggregate formation to regulate stem cell behavior as well as a bottom-up and a top-down microengineering approach to creating biomimic tissue-like structures. PMID:21344063

Electrical Microengineering of Redox Enzymes

DTIC Science & Technology

1994-03-31

coating applied to the electrode 41 to prevent lose of mediator graphite foil potassium -~0.02a 0.03  electrolyte wus dioxane with 15% 42...hexacyanoferrats(ll)d aqueous buffer carbon fiber’ none h 40-5000 biotin/avidin complex used to obtain a 43 surface layer of HRP Pt organic metal, potassium ...OFFICE OF NAVAL RESEARCH AD-A279 015 FINAL REPORT FOR CONTRACT NOOO 14-91 -J- 1656 R&T CODE 413h007---05 ELECTRICAL MICROENGINEERING OF REDOX ENZYMES

Hydrogen generation having CO₂ removal with steam reforming

DOEpatents

Kandaswamy, Duraiswamy; Chellappa, Anand S.; Knobbe, Mack

2015-07-28

A method for producing hydrogen using fuel cell off gases, the method feeding hydrocarbon fuel to a sulfur adsorbent to produce a desulfurized fuel and a spent sulfur adsorbent; feeding said desulfurized fuel and water to an adsorption enhanced reformer that comprises of a plurality of reforming chambers or compartments; reforming said desulfurized fuel in the presence of a one or more of a reforming catalyst and one or more of a CO₂ adsorbent to produce hydrogen and a spent CO₂ adsorbent; feeding said hydrogen to the anode side of the fuel cell; regenerating said spent CO₂ adsorbents using the fuel cell cathode off-gases, producing a flow of hydrogen by cycling between said plurality of reforming chambers or compartments in a predetermined timing sequence; and, replacing the spent sulfur adsorbent with a fresh sulfur adsorbent at a predetermined time.

Smart membranes for nitrate removal, water purification, and selective ion transportation

DOEpatents

Wilson, William D [Pleasanton, CA; Schaldach, Charlene M [Pleasanton, CA; Bourcier, William L [Livermore, CA; Paul, Phillip H [Livermore, CA

2009-12-15

A computer designed nanoengineered membrane for separation of dissolved species. One embodiment provides an apparatus for treatment of a fluid that includes ions comprising a microengineered porous membrane, a system for producing an electrical charge across the membrane, and a series of nanopores extending through the membrane. The nanopores have a pore size such that when the fluid contacts the membrane, the nanopores will be in a condition of double layer overlap and allow passage only of ions opposite to the electrical charge across the membrane.

Design and optimization of the micro-engine turbine rotor manufacturing using the rapid prototyping technology

NASA Astrophysics Data System (ADS)

Vdovin, R. A.; Smelov, V. G.

2017-02-01

This work describes the experience in manufacturing the turbine rotor for the micro-engine. It demonstrates the design principles for the complex investment casting process combining the use of the ProCast software and the rapid prototyping techniques. At the virtual modelling stage, in addition to optimized process parameters, the casting structure was improved to obtain the defect-free section. The real production stage allowed demonstrating the performance and fitness of rapid prototyping techniques for the manufacture of geometrically-complex engine-building parts.

Micro-engineered remote palpation device for assessing tissue compliance.

PubMed

Hien, M; Yang, T H J; Leung, S K W; Reuben, R L; Habib, F K; McNeill, S A; Schneider, A; McBride, G; Stevens, R; Else, R W

2008-01-01

This paper concerns the operation of the actuator for a prototype micro-engineered mechanical palpation device for deployment via a cystoscope to measure the dynamic mechanical properties of the prostate gland in vivo. The subassembly consists of a 400x200 microm silicon (Si) piston manufactured using deep reactive ion etching (DRIE) housed within an anodically bonded glass-Si-glass sandwiched housing. The micro-channel on the Si layer was formed by powder blasting and contains the micro-piston with one end pointing to the side of the housing and the other facing a via hole leading to a capillary tube. The opening on the side of the housing was sealed by a 5 microm thick silicone membrane which acts to retain the micro-piston and act as a return spring. A 320 microm diameter capillary forms the connection between the micro-channel and a micro-syringe which is operated by a programmable syringe pump to produce a reciprocating action. A pressure sensor is connected along the capillary tube to measure the dynamic pressure within the system. The micro-piston has already been used, separately actuated to measure the dynamic mechanical properties of known viscoelastic materials and prostate tissue. The purpose of the present work is to assess the functionality of the actuator assembly.

PUBLISHER'S ANNOUNCEMENT: A revised scope for Journal of Micromechanics and Microengineering A revised scope for Journal of Micromechanics and Microengineering

NASA Astrophysics Data System (ADS)

Forbes, Ian

2010-05-01

Journal of Micromechanics and Microengineering is well known for publishing excellent work in highly competitive timescales. The journal's coverage has consistently evolved to reflect the current state of the field, and from May 2010 it will revisit its scope once again. The aims of the journal remain unchanged, however: to be the first choice of authors and readers in MEMS and micro-scale research. The new scope continues to focus on highlighting the link between fabrication technologies and their capacity to create novel devices. This link will be considered paramount in the journal, and both prospective authors and readers should let it serve as an inspiration to them. The burgeoning fields of NEMS and nano-scale engineering are more explicitly supported in the new scope. Research which ten years ago would have been considered science fiction has, through the tireless efforts of the community, become reality. The Editorial Board feel it is important to reflect the growing significance of this work in the scope. The new scope, drafted by Editor-in-Chief Professor Mark Allen, and approved by the Editorial Board, is as follows: Journal of Micromechanics and Microengineering covers all aspects of microelectromechanical structures, devices, and systems, as well as micromechanics and micromechatronics. The journal focuses on original work in fabrication and integration technologies, on the micro- and nano-scale. The journal aims to highlight the link between new fabrication technologies and their capacity to create novel devices. Original work in microengineering and nanoengineering is also reported. Such work is defined as applications of these fabrication and integration technologies to structures in which key attributes of the devices or systems depend on specific micro- or nano-scale features. Such applications span the physical, chemical, electrical and biological realms. New fabrication and integration techniques for both silicon and non-silicon materials are reported. Relevant modelling papers in micro- and nanoengineering are reported where supported by experimental data. The journal also covers integration of interface electronics with micro- and nanoengineered systems, as well as vacuum microelectronics, microfabricated electrically passive elements, and other micro- or nanoengineering-enabled electrical devices.

The design, fabrication and characterization of fluidic membranes for micro-engines with the aim of frequency lowering

NASA Astrophysics Data System (ADS)

Chutani, R.; Formosa, F.; de Labachelerie, M.; Badel, A.; Lanzetta, F.

2016-12-01

This paper describes the design, microfabrication and linear dynamic characterization of low frequency thick membranes as a potential technological solution for resonant micro-engines, for which classical pistons cannot be used. The proposed structure is called a hybrid fluid-membrane and consists of two thin flexible membranes that encapsulate an incompressible fluid. Lower frequency structures, compared to geometrically equivalent single layer membranes, are thus obtained. Each flexible membrane is based on a composite structure which comprises a silicon planar logarithmic spiral spring embedded in a room temperature vulcanization silicone polymer. Thus, the stiffness and sealing features are dissociated for a better design control. The developed realization and assembly process is demonstrated at the wafer level. The process involves the anodic bonding of multiple stacks of silicon/glass structures, fluid filling and sealing. Various dimensions of hybrid fluid-membranes are successfully fabricated. Their dynamic characterization underlines the agreement between experimental and theoretical results. The results provide the opportunity for the design and fabrication of low frequency membranes to match the dynamics requirements of micro-engines.

Where microbiology meets microengineering: design and applications of reporter bacteria.

PubMed

van der Meer, Jan Roelof; Belkin, Shimshon

2010-07-01

Bacteria have long been the targets for genetic manipulation, but more recently they have been synthetically designed to carry out specific tasks. Among the simplest of these tasks is chemical compound and toxicity detection coupled to the production of a quantifiable reporter signal. In this Review, we describe the current design of bacterial bioreporters and their use in a range of assays to measure the presence of harmful chemicals in water, air, soil, food or biological specimens. New trends for integrating synthetic biology and microengineering into the design of bacterial bioreporter platforms are also highlighted.

Microfabrication of hybrid fluid membrane for microengines

NASA Astrophysics Data System (ADS)

Chutani, R.; Formosa, F.; de Labachelerie, M.; Badel, A.; Lanzetta, F.

2015-12-01

This paper describes the microfabrication and dynamic characterization of thick membranes providing a technological solution for microengines. The studied membranes are called hybrid fluid-membrane (HFM) and consist of two thin membranes that encapsulate an incompressible fluid. This work details the microelectromechanical system (MEMS) scalable fabrication and characterization of HFMs. The membranes are composite structures based on Silicon spiral springs embedded in a polymer (RTV silicone). The anodic bonding of multiple stacks of Si/glass structures, the fluid filling and the sealing have been demonstrated. Various HFMs were successfully fabricated and their dynamic characterization demonstrates the agreement between experimental and theoretical results.

Microengineering of Metals and Ceramics: Part I: Design, Tooling and Injection Molding; Volume 3: Advanced Micro & Nanosystems

NASA Astrophysics Data System (ADS)

Baltes, Henry; Brand, Oliver; Fedder, Gary K.; Hierold, Christofer; Korvink, Jan G.; Tabata, Osamu; Löhe, Detlef; Haußelt, Jürgen

2005-09-01

Microstructures, electronics, nanotechnology - these vast fields of research are growing together as the size gap narrows and many different materials are combined. Current research, engineering sucesses and newly commercialized products hint at the immense innovative potentials and future applications that open up once mankind controls shape and function from the atomic level right up to the visible world without any gaps. In this volume, authors from three major competence centres for microengineering illustrate step by step the process from designing and simulating microcomponents of metallic and ceramic materials to replicating micro-scale components by injection molding.

A microengineered model of RBC transfusion-induced pulmonary vascular injury.

PubMed

Seo, Jeongyun; Conegliano, David; Farrell, Megan; Cho, Minseon; Ding, Xueting; Seykora, Thomas; Qing, Danielle; Mangalmurti, Nilam S; Huh, Dongeun

2017-06-13

Red blood cell (RBC) transfusion poses significant risks to critically ill patients by increasing their susceptibility to acute respiratory distress syndrome. While the underlying mechanisms of this life-threatening syndrome remain elusive, studies suggest that RBC-induced microvascular injury in the distal lung plays a central role in the development of lung injury following blood transfusion. Here we present a novel microengineering strategy to model and investigate this key disease process. Specifically, we created a microdevice for culturing primary human lung endothelial cells under physiological flow conditions to recapitulate the morphology and hemodynamic environment of the pulmonary microvascular endothelium in vivo. Perfusion of the microengineered vessel with human RBCs resulted in abnormal cytoskeletal rearrangement and release of intracellular molecules associated with regulated necrotic cell death, replicating the characteristics of acute endothelial injury in transfused lungs in vivo. Our data also revealed the significant effect of hemodynamic shear stress on RBC-induced microvascular injury. Furthermore, we integrated the microfluidic endothelium with a computer-controlled mechanical stretching system to show that breathing-induced physiological deformation of the pulmonary microvasculature may exacerbate vascular injury during RBC transfusion. Our biomimetic microsystem provides an enabling platform to mechanistically study transfusion-associated pulmonary vascular complications in susceptible patient populations.

Microengineering as a tool to study substratum modulation and cell behaviour.

PubMed

Keatch, R P; Armoogum, K; Schor, S L; Pridham, M S; Banks, K; Khor, T Y; Matthew, C

2002-01-01

This research is an investigation of the means by which geometrical parameters (e.g. area and shape) and various surface attributes (materials and surface finish) of microengineered structures can modulate cellular response. This is based on biological observations indicating that: (i) the response of tissue cells to injury is determined by the net signal transduction response elicited by soluble regulatory molecules (e.g. cytokines), (ii) common matrix constituents (e.g. collagen) directly affect cell behaviour by the same signal transduction mechanisms mediating cytokine bioactivity, (iii) cellular response to cytokines is modulated by the precise nature of the extracellular matrix to which the target cells are adherent, including its biochemical composition and physical structure.

Three-dimensional microelectromechanical tilting platform operated by gear-driven racks

DOEpatents

Klody, Kelly A.; Habbit, Jr., Robert D.

2005-11-01

A microelectromechanical (MEM) tiltable-platform apparatus is disclosed which utilizes a light-reflective platform (i.e. a micromirror) which is supported above a substrate by flexures which can be bent upwards to tilt the platform in any direction over an angle of generally .+-.10 degrees using a gear-driven rack attached to each flexure. Each rack is driven by a rotary microengine (i.e. a micromotor); and an optional thermal actuator can be used in combination with each microengine for initially an initial uplifting of the platform away from the substrate. The MEM apparatus has applications for optical switching (e.g. between a pair of optical fibers) or for optical beam scanning.

Microengineering methods for cell-based microarrays and high-throughput drug-screening applications.

PubMed

Xu, Feng; Wu, JinHui; Wang, ShuQi; Durmus, Naside Gozde; Gurkan, Umut Atakan; Demirci, Utkan

2011-09-01

Screening for effective therapeutic agents from millions of drug candidates is costly, time consuming, and often faces concerns due to the extensive use of animals. To improve cost effectiveness, and to minimize animal testing in pharmaceutical research, in vitro monolayer cell microarrays with multiwell plate assays have been developed. Integration of cell microarrays with microfluidic systems has facilitated automated and controlled component loading, significantly reducing the consumption of the candidate compounds and the target cells. Even though these methods significantly increased the throughput compared to conventional in vitro testing systems and in vivo animal models, the cost associated with these platforms remains prohibitively high. Besides, there is a need for three-dimensional (3D) cell-based drug-screening models which can mimic the in vivo microenvironment and the functionality of the native tissues. Here, we present the state-of-the-art microengineering approaches that can be used to develop 3D cell-based drug-screening assays. We highlight the 3D in vitro cell culture systems with live cell-based arrays, microfluidic cell culture systems, and their application to high-throughput drug screening. We conclude that among the emerging microengineering approaches, bioprinting holds great potential to provide repeatable 3D cell-based constructs with high temporal, spatial control and versatility.

Thin teflon-like films for MEMS: Film properties and reliability studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, B.K.; LaVigne, G.; Sniegowski, J.J.

1998-07-01

This work presents film properties and initial reliability studies for thin Teflon-like films applied to a unique test vehicle, the Sandia-designed and fabricated microengine. Results on microengines coated with the film show a factor of three improvement in their lifetime and an order of magnitude reduction in the coefficient of friction when compared to uncoated samples. Coefficients Of Friction (COF) of 0.07 for the Teflon-like film and 1.0 for uncoated samples are extracted from models which match the measured behavior of working microengines. These films, deposited form a plasma source, exhibit the ability to penetrate into very narrow, deep channelsmore » common to many MEMS devices. For as-deposited film, both the refractive index at 1.4 and the contact angle with water at 108{degree} show the film to be very similar to bulk Teflon PTFE. Film stability as a function of temperature has been examined using Fourier Transformation Infrared (FTIR) spectroscopy. The film structure as observed by the fluorine-carbon (F-C) peak is stable up to 200 C, but starts decomposing above 250 C. Film composition has been examined using X-ray photoelectron spectroscopy (XPS) and is quite different for directly exposed surfaces compared with deep, narrow channels where the deposition process is diffusion limited.« less

Advanced biomaterials and microengineering technologies to recapitulate the stepwise process of cancer metastasis.

PubMed

Peela, Nitish; Truong, Danh; Saini, Harpinder; Chu, Hunghao; Mashaghi, Samaneh; Ham, Stephanie L; Singh, Sunil; Tavana, Hossein; Mosadegh, Bobak; Nikkhah, Mehdi

2017-07-01

Cancer is one of the leading causes of death globally according to the World Health Organization. Although improved treatments and early diagnoses have reduced cancer related mortalities, metastatic disease remains a major clinical challenge. The local tumor microenvironment plays a significant role in cancer metastasis, where tumor cells respond and adapt to a plethora of biochemical and biophysical signals from stromal cells and extracellular matrix (ECM) proteins. Due to these complexities, there is a critical need to understand molecular mechanisms underlying cancer metastasis to facilitate the discovery of more effective therapies. In the past few years, the integration of advanced biomaterials and microengineering approaches has initiated the development of innovative platform technologies for cancer research. These technologies enable the creation of biomimetic in vitro models with physiologically relevant (i.e. in vivo-like) characteristics to conduct studies ranging from fundamental cancer biology to high-throughput drug screening. In this review article, we discuss the biological significance of each step of the metastatic cascade and provide a broad overview on recent progress to recapitulate these stages using advanced biomaterials and microengineered technologies. In each section, we will highlight the advantages and shortcomings of each approach and provide our perspectives on future directions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microengineering Methods for Cell Based Microarrays and High-Throughput Drug Screening Applications

PubMed Central

Xu, Feng; Wu, JinHui; Wang, ShuQi; Durmus, Naside Gozde; Gurkan, Umut Atakan; Demirci, Utkan

2011-01-01

Screening for effective therapeutic agents from millions of drug candidates is costly, time-consuming and often face ethical concerns due to extensive use of animals. To improve cost-effectiveness, and to minimize animal testing in pharmaceutical research, in vitro monolayer cell microarrays with multiwell plate assays have been developed. Integration of cell microarrays with microfluidic systems have facilitated automated and controlled component loading, significantly reducing the consumption of the candidate compounds and the target cells. Even though these methods significantly increased the throughput compared to conventional in vitro testing systems and in vivo animal models, the cost associated with these platforms remains prohibitively high. Besides, there is a need for three-dimensional (3D) cell based drug-screening models, which can mimic the in vivo microenvironment and the functionality of the native tissues. Here, we present the state-of-the-art microengineering approaches that can be used to develop 3D cell based drug screening assays. We highlight the 3D in vitro cell culture systems with live cell-based arrays, microfluidic cell culture systems, and their application to high-throughput drug screening. We conclude that among the emerging microengineering approaches, bioprinting holds a great potential to provide repeatable 3D cell based constructs with high temporal, spatial control and versatility. PMID:21725152

Characterization and Testing of Amidoxime-Based Adsorbent Materials to Extract Uranium from Natural Seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, Li-Jung; Janke, Christopher J.; Wood, Jordana R.

Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL)’s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This manuscript describes the performance of three formulations (38H, AF1, AI8) ofmore » amidoxime-based polymeric adsorbents produced at ORNL in MSL’s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), and exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 g U/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with a 56 day capacity of 3.9 g U/ kg adsorbent, a saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flowthrough columns and flumes, were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10’s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and confirm that the manufacturing process produces a homogeneous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater, to 8-10 weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

Characterization and testing of amidoxime-based adsorbent materials to extract uranium from natural seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, Li-Jung; Janke, Christopher James; Wood, Jordana

Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL) s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This report describes the performance of three formulations (38H, AF1, AI8)more » of amidoxime-based polymeric adsorbent produced at ORNL in MSL s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 gU/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with 56-day capacity of 3.9 g U/kg adsorbent, saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flow-through columns and flumes were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10 s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and that the manufacturing process produces a homogenous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater to 8-10weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

Characterization and testing of amidoxime-based adsorbent materials to extract uranium from natural seawater

DOE PAGES

Kuo, Li-Jung; Janke, Christopher James; Wood, Jordana; ...

2015-11-19

Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL) s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This report describes the performance of three formulations (38H, AF1, AI8)more » of amidoxime-based polymeric adsorbent produced at ORNL in MSL s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 gU/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with 56-day capacity of 3.9 g U/kg adsorbent, saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flow-through columns and flumes were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10 s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and that the manufacturing process produces a homogenous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater to 8-10weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

Microfabrication of Cell-Laden Hydrogels for Engineering Mineralized and Load Bearing Tissues.

PubMed

Li, Chia-Cheng; Kharaziha, Mahshid; Min, Christine; Maas, Richard; Nikkhah, Mehdi

2015-01-01

Microengineering technologies and advanced biomaterials have extensive applications in the field of regenerative medicine. In this chapter, we review the integration of microfabrication techniques and hydrogel-based biomaterials in the field of dental, bone, and cartilage tissue engineering. We primarily discuss the major features that make hydrogels attractive candidates to mimic extracellular matrix (ECM), and we consider the benefits of three-dimensional (3D) culture systems for tissue engineering applications. We then focus on the fundamental principles of microfabrication techniques including photolithography, soft lithography and bioprinting approaches. Lastly, we summarize recent research on microengineering cell-laden hydrogel constructs for dental, bone and cartilage regeneration, and discuss future applications of microfabrication techniques for load-bearing tissue engineering.

Application of multiwalled carbon nanotubes and its magnetite derivative for emulsified oil removal from produced water.

PubMed

Ibrahim, Taleb H; Sabri, Muhammad A; Khamis, Mustafa I

2018-05-10

Multiwalled carbon nanotubes and their magnetite derivatives were employed as adsorbents for emulsified oil removal from produced water. The experimental parameters for maximum emulsified oil removal efficiency and effective regeneration of these adsorbents were determined. The optimum parameters in terms of adsorbent dosage, contact time, salinity, pH and temperature were 3.0 g/L, 20.0 min, 0 ppm, 7.0 and 25°C for both adsorbents. Due to their low density, multiwalledcarbon nanotubes could not be successfully employed in packed bed columns. The magnetite derivative has a larger density and hence, for the removal of emulsified oil from produced water packed bed column studies were performed utilizing multiwalled carbon magnetite nanotubes. The packed bed column efficiency and behaviour were evaluated using Thomas, Clark, Yan et al. and Bohart and Adams models. The Yan model was found to best describe the column experimental data. The adsorbents were regenerated using n-hexane and reused several times for oil removal from produced water without any significant decrease in their initial adsorption capacities.

Magnetic assembly and annealing of colloidal lattices and superlattices.

PubMed

Tierno, Pietro

2014-07-08

The ability to assemble mesoscopic colloidal lattices above a surface is important for fundamental studies related with nucleation and crystallization but also for a variety of technological applications in photonics and microengineering. Current techniques based on particle sedimentation above a lithographic template are limited by a slow deposition process and by the use of static templates, which make difficult to implement fast annealing procedures. Here it is demonstrated a method to realize and anneal a series of colloidal lattices displaying triangular, honeycomb, or kagome-like symmetry above a structure magnetic substrate. By using a binary mixture of particles, superlattices can be realized increasing further the variety and complexity of the colloidal patterns which can be produced.

EDITORIAL: Welcome to the 2008 volume

NASA Astrophysics Data System (ADS)

Puers, R.

2008-01-01

It is my pleasure to address these few lines to you all on the occasion of the start of the 2008 volume of Journal of Micromechanics and Microengineering, the journal's eighteenth year, and my eleventh year of service as Editor-in-Chief. As in previous years, I would like to take the opportunity to reflect on the achievements of the past year. The number of submissions to the journal continues to grow, to almost 800 in 2007. Importantly, the journal's ISI® impact factor remains at a solid 2.321. This is an achievement we can all be proud of. In 2007, an incredible 350 000 papers were downloaded, which clearly reflects the visibility and appreciation of our research work. These excellent results are entirely due to the fact that more of you are choosing to submit your high-quality work to the journal, and because more of you are also choosing to cite recent papers published within the journal. I would like to take this opportunity to thank each one of you: readers, authors and referees alike. To cope with the steadily increasing number of incoming papers, the review process had to be expanded. In 2007, more than 700 experts selected from 35 countries agreed to our requests to referee. In the name of the entire team, I would like to express my thanks to all our referees for their careful and well constructed reports, which are of paramount importance in maintaining the quality standards of Journal of Micromechanics and Microengineering. The average time to produce an individual report is a mere 19 days, contributing towards a very favourable overall processing time which is an attractive feature of the journal. Of course all this would not be possible without the constant hard work of the publishing, production and marketing staff in Bristol. In the name of the Editorial Board, contributing authors and readers, I wish to thank them for their support. Finally, I believe we have established a clear and distinct profile in the broad spectrum of journals in our field, and I hope we can expand this profile even further. This is not possible without the efforts of every individual researcher in our community. I therefore wish each of you a prosperous and adventurous 2008 in your quest to shift the frontiers in micromachining and microengineering. May health and prosperity be yours as you work to achieve these goals!

A microengineered pathophysiological model of early-stage breast cancer.

PubMed

Choi, Yoonseok; Hyun, Eunjeh; Seo, Jeongyun; Blundell, Cassidy; Kim, Hee Chan; Lee, Eunhee; Lee, Su Hyun; Moon, Aree; Moon, Woo Kyung; Huh, Dongeun

2015-08-21

A mounting body of evidence in cancer research suggests that the local microenvironment of tumor cells has a profound influence on cancer progression and metastasis. In vitro studies on the tumor microenvironment and its pharmacological modulation, however, are often hampered by the technical challenges associated with creating physiological cell culture environments that integrate cancer cells with the key components of their native niche such as neighboring cells and extracellular matrix (ECM) to mimic complex microarchitecture of cancerous tissue. Using early-stage breast cancer as a model disease, here we describe a biomimetic microengineering strategy to reconstitute three-dimensional (3D) structural organization and microenvironment of breast tumors in human cell-based in vitro models. Specifically, we developed a microsystem that enabled co-culture of breast tumor spheroids with human mammary ductal epithelial cells and mammary fibroblasts in a compartmentalized 3D microfluidic device to replicate microarchitecture of breast ductal carcinoma in situ (DCIS). We also explored the potential of this breast cancer-on-a-chip system as a drug screening platform by evaluating the efficacy and toxicity of an anticancer drug (paclitaxel). Our microengineered disease model represents the first critical step towards recapitulating pathophysiological complexity of breast cancer, and may serve as an enabling tool to systematically examine the contribution of the breast cancer microenvironment to the progression of DCIS to an invasive form of the disease.

Microfabrication of human organs-on-chips.

PubMed

Huh, Dongeun; Kim, Hyun Jung; Fraser, Jacob P; Shea, Daniel E; Khan, Mohammed; Bahinski, Anthony; Hamilton, Geraldine A; Ingber, Donald E

2013-11-01

'Organs-on-chips' are microengineered biomimetic systems containing microfluidic channels lined by living human cells, which replicate key functional units of living organs to reconstitute integrated human organ-level pathophysiology in vitro. These microdevices can be used to test efficacy and toxicity of drugs and chemicals, and to create in vitro models of human disease. Thus, they potentially represent low-cost alternatives to conventional animal models for pharmaceutical, chemical and environmental applications. Here we describe a protocol for the fabrication, microengineering and operation of these microfluidic organ-on-chip systems. First, microengineering is used to fabricate a multilayered microfluidic device that contains two parallel elastomeric microchannels separated by a thin porous flexible membrane, along with two full-height, hollow vacuum chambers on either side; this requires ∼3.5 d to complete. To create a 'breathing' lung-on-a-chip that mimics the mechanically active alveolar-capillary interface of the living human lung, human alveolar epithelial cells and microvascular endothelial cells are cultured in the microdevice with physiological flow and cyclic suction applied to the side chambers to reproduce rhythmic breathing movements. We describe how this protocol can be easily adapted to develop other human organ chips, such as a gut-on-a-chip lined by human intestinal epithelial cells that experiences peristalsis-like motions and trickling fluid flow. Also, we discuss experimental techniques that can be used to analyze the cells in these organ-on-chip devices.

Computer Generated Diffraction Patterns Of Rough Surfaces

NASA Astrophysics Data System (ADS)

Rakels, Jan H.

1989-03-01

It is generally accepted, that optical methods are the most promising for the in-process measurement of surface finish. These methods have the advantages of being non-contacting and fast data acquisition. In the Micro-Engineering Centre at the University of Warwick, an optical sensor has been devised which can measure the rms roughness, slope and wavelength of turned and precision ground surfaces. The operation of this device is based upon the Kirchhoff-Fresnel diffraction integral. Application of this theory to ideal turned surfaces is straightforward, and indeed the theoretically calculated diffraction patterns are in close agreement with patterns produced by an actual optical instrument. Since it is mathematically difficult to introduce real surface profiles into the diffraction integral, a computer program has been devised, which simulates the operation of the optical sensor. The program produces a diffraction pattern as a graphical output. Comparison between computer generated and actual diffraction patterns of the same surfaces show a high correlation.

Cellular and multicellular form and function.

PubMed

Liu, Wendy F; Chen, Christopher S

2007-11-10

Engineering artificial tissue constructs requires the appropriate spatial arrangement of cells within scaffolds. The introduction of microengineering tools to the biological community has provided a valuable set of techniques to manipulate the cellular environment, and to examine how cell structure affects cellular function. Using micropatterning techniques, investigators have found that the geometric presentation of cell-matrix adhesions are important regulators of various cell behaviors including cell growth, proliferation, differentiation, polarity and migration. Furthermore, the presence of neighboring cells in multicellular aggregates has a significant impact on the proliferative and differentiated state of cells. Using microengineering tools, it will now be possible to manipulate the various environmental factors for practical applications such as engineering tissue constructs with greater control over the physical structure and spatial arrangement of cells within their surrounding microenvironment.

Microengineering of Metals and Ceramics: Part II: Special Replication Techniques, Automation and Properties; Volume 4: Advanced Micro & Nanosystems

NASA Astrophysics Data System (ADS)

Baltes, Henry; Brand, Oliver; Fedder, Gary K.; Hierold, Christofer; Korvink, Jan G.; Tabata, Osamu; Löhe, Detlef; Haußelt, Jürgen

2005-10-01

Microstructures, electronics, nanotechnology - these vast fields of research are growing together as the size gap narrows and many different materials are combined. Current research, engineering sucesses and newly commercialized products hint at the immense innovative potentials and future applications that open up once mankind controls shape and function from the atomic level right up to the visible world without any gaps. Continuing from the previous volume, authors from three major competence centres for microengineering here cover all aspects of specialized replication techniques and how to employ state-of-the-art technologies for testing and characterizing micro-scale components, and illustrate quality control aspects and strategies for automation of production procedures in view of future industrial production and commercialisation.

Micro-engineering a platform to reconstruct physiology and functionality of the human brain microvasculature in vitro

NASA Astrophysics Data System (ADS)

Daghighi, Yasaman; Heidari, Hossein; Taylor, Hayden

2018-02-01

A predominant unsolved challenge in tissue engineering is the need of a robust technique for producing vascular networks, particularly when modeling human brain tissue. The availability of reliable in vitro human brain microvasculature models would advance our understanding of its function and would provide a platform for highthroughput drug screening. Current strategies for modeling vascularized brain tissue suffer from limitations such as (1) culturing non-human cell lines, (2) limited multi-cell co-culture, and (3) the effects of neighboring physiologically unrealistic rigid polymeric surfaces, such as solid membranes. We demonstrate a new micro-engineered platform that can address these shortcomings. Specifically, we have designed and prototyped a molding system to enable the precise casting of 100μm-diameter coaxial hydrogel structures laden with the requisite cells to mimic a vascular lumen. Here we demonstrate that a fine wire with diameter 130 μm or a needle with outer diameter 300 μm can be used as a temporary mold insert, and agarose-collagen composite matrix can be cast around these inserts and thermally gelled. When the wire or needle is retracted under the precise positional control afforded by our system, a microchannel is formed which is then seeded with human microvascular endothelial cells. After seven days of culture these cells produce an apparently confluent monolayer on the channel walls. In principle, this platform could be used to create multilayered cellular structures. By arranging a fine wire and a hollow needle coaxially, three distinct zones could be defined in the model: first, the bulk gel surrounding the needle; then, after needle retraction, a cylindrical shell of matrix; and finally, after retraction of the wire, a lumen. Each zone could be independently cell-seeded. To this end, we have also successfully 3D cultured human astrocytes and SY5Y glial cells in our agarose-collagen matrix. Our approach ultimately promises scalable and repeatable production of vascular structures with physiologically realistic mechanical properties.

Synthetic Micro/Nanomachines and Their Applications: Towards 'Fantastic Voyage'

NASA Astrophysics Data System (ADS)

Gao, Wei

The 1966 movie Fantastic Voyage captured the world's imagination, portraying a tiny submarine navigating through the human bloodstream and treating life-threatening medical conditions. My PhD research focuses on the synthetic nano/microscale machines to realize the Fantastic Voyage vision. Various biomedical and environmental areas would benefit from the developments of efficient fuel-free and fuel-driven nano/microscale machines. The polymer-based catalytic tubular microengine is synthesized using a template based electrodeposition method. The oxygen bubble propelled microengine harvests the energy from chemical fuels (such as H2O2) and displays very efficient propulsion. It can serve as an ideal platform for diverse biomedical and environmental applications. For example, lectin modified polyaniline based microengines can be used for selective bacteria (E. Coli) isolation from food, clinical and environmental samples; poly(3-aminophenylboronic acid)/Ni/Pt microengine itself provides the 'built in' glucose recognition capability for 'on-the-fly' capture, transport and release of yeast cells. A series of micromotors which can be self-propelled in natural environments without additional chemical fuels are developed, holding great promise for in vivo biomedical applications: the polyaniline/zinc microrockets display effective autonomous motion in extreme acidic environments (such as human stomach); the Al-Ga/Ti based Janus micromotor can be propelled by the hydrogen bubbles generated from the rapid aluminum and water reaction; alkanethiols modified seawater-driven Mg Janus micromotors, which utilize macrogalvanic corrosion and chloride pitting corrosion processes, can be used for environmental oil remediation. Magnetically powered nanoswimmers have attracted considerable attention due to their great biocompatibility. A high-speed magnetically-propelled nanowire swimmer which mimics swimming microorganisms by exploiting the flexible nanowire as artificial flagella under rotating magnetic field is illustrated. New bioinspired microswimmers can also be prepared directly from isolated spiral vessels of plants, harnessing the intrinsic biological structures of nature. Potential applications of these cargo-towing nanoswimmers are demonstrated by the directed delivery of drug-loaded microparticles to HeLa cancer cells in biological media. With such innovations and developments, along with careful attention to key challenges and requirements, nano/microscale motors are expected to have tremendous impact on diverse biomedical and environmental applications, providing unlimited opportunities limited only by one's imagination.

The influence of low-energy helium plasma on bubble formation in micro-engineered tungsten

NASA Astrophysics Data System (ADS)

Gao, Edward; Nadvornick, Warren; Doerner, Russ; Ghoniem, Nasr M.

2018-04-01

Four different types of micro-engineered tungsten surfaces were exposed to low energy helium plasma, with a planar surface as control. These samples include two surfaces covered with uniform W-coated rhenium micro-pillars; one with cylindrical pillars 1 μm in diameter and 25 μm in height, and one with dendritic conical pillars 4-10 μm in diameter and 20 μm in height. Additionally, two samples with reticulated open-cell foam geometry, one at 45 pores per inch (PPI), and the other at 80 PPI were fabricated with Chemical Vapor Deposition (CVD). The samples were exposed to helium plasma at 30-100 eV ion energy, 823-1123 K temperature, and 5 × 1025 - 2 × 1026 m-2 ion fluence. It is shown that the formation of nanometer-scale tendrils (fuzz) on micro-engineered W surfaces is greatly reduced as compared to planar surfaces. This is attributed to more significant ion backscattering and the increased effective surface area that intercept incident ions in micro-engineered W. A 20% decrease in the average ion incident angle on pillar type surfaces leads to ∼30% decrease in bubble size, down to 30 nm in diameter. W fuzz was found to be absent from pillar sides due to high ion backscattering rates from pillar sides. In foam samples, 28% higher PPI is observed to have 24.7%-36.7% taller fuzz, and 17.0%-25.0% larger subsurface bubbles. These are found to be an order of magnitude smaller than those found in planar surfaces of similar environment. The helium bubble density was found to increase with ion energy in pillars, roughly from 8.2% to 48.4%, and to increase with increasing PPI, from 36.4% to 116.2%, and with bubble concentrations up to 9.1 × 1021 m-3. Geometric shadowing effects in or near surface ligaments are observed in all foam samples, with near absence of helium bubbles or fuzz in deeper layers of the foam.

Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water.

PubMed

Méndez, A; Barriga, S; Fidalgo, J M; Gascó, G

2009-06-15

This paper deals with the removal of Cu(2+) from water using adsorbent materials prepared from paper industry waste materials (one de-inking paper sludge and other sludge from virgin pulp mill). Experimental results showed that de-inking paper sludge leads to mesoporous materials (V(mic)/V(T)=0.13 and 0.14), whereas the sludge from virgin pulp mill produces high microporous adsorbents (V(mic)/V(T)=0.39 and 0.41). Adsorbent materials were then used for Cu(2+) removal from water at acid pH. During water treatment, heavy metals lixiviation from adsorbent materials was not produced. However, important Ca and Mg leaching was observed. Final pH significantly increases after treatment of water with adsorbent materials probably due to their elevated CaCO(3) content. In general, highest Cu(2+) removal was obtained using adsorbent materials from de-inking paper sludge. This result could be due to their higher content in oxygenated surface groups, high average pore diameter, elevated superficial charge density, high CaCO(3) amount and high Ca and Mg exchange content.

Microfluidics: Science and Engineering at the Edge of the Continuum

NASA Astrophysics Data System (ADS)

Breuer, Kenny

2002-11-01

The widespread growth of microengineering and the development of a new generation of micron- and nanometer scale diagnostic techniques has focussed much recent attention on the mechanics of fluids at the micron and sub-micron scale. Challenges with both scientific and engineering relevance have been raised by this activity, ranging from the prediction of viscous damping and lubrication effects in MEMS to the design of microengines to the understanding of bacterial propulsion. Identifying and addressing these challenges form the basis of this talk. >From a scientific perspective, a question that refuses to die is that of the applicability of the continuum hypothesis, and the possible existence of new physical phenomena only observable in small systems. To be brief, the reports of the demise of the Navier-Stokes equations are greatly exaggerated and to illustrate this we will review the more recent work on near-continuum fluid mechanics in micron and sub-micron scale devices with an emphasis on our own experiments on the breakdown of the continuum description in both gaseous and liquid flows. From an engineering perspective, the tight coupling between fluids, structures and manufacturing result in flows characterized by unfamiliar parameter regimes and unconventional geometries. We will look at several examples of such microfluidic engineering, drawn from MEMS (inertial instruments, microengines) and biology (bacterial propulsion) that illustrate the the unique design challenges that we encounter in microfluidic devices and the solutions (and lack of solutions) to these problems.

Small-scale heat detection using catalytic microengines irradiated by laser

NASA Astrophysics Data System (ADS)

Liu, Zhaoqian; Li, Jinxing; Wang, Jiao; Huang, Gaoshan; Liu, Ran; Mei, Yongfeng

2013-01-01

We demonstrate a novel approach to modulating the motion speed of catalytic microtubular engines via laser irradiation/heating with regard to small-scale heat detection. Laser irradiation on the engines leads to a thermal heating effect and thus enhances the engine speed. During a laser on/off period, the motion behaviour of a microengine can be repeatable and reversible, demonstrating a regulation of motion speeds triggered by laser illumination. Also, the engine velocity exhibits a linear dependence on laser power in various fuel concentrations, which implies an application potential as local heat sensors. Our work may hold great promise in applications such as lab on a chip, micro/nano factories, and environmental detection.We demonstrate a novel approach to modulating the motion speed of catalytic microtubular engines via laser irradiation/heating with regard to small-scale heat detection. Laser irradiation on the engines leads to a thermal heating effect and thus enhances the engine speed. During a laser on/off period, the motion behaviour of a microengine can be repeatable and reversible, demonstrating a regulation of motion speeds triggered by laser illumination. Also, the engine velocity exhibits a linear dependence on laser power in various fuel concentrations, which implies an application potential as local heat sensors. Our work may hold great promise in applications such as lab on a chip, micro/nano factories, and environmental detection. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr32494f

Microengineered physiological biomimicry: organs-on-chips.

PubMed

Huh, Dongeun; Torisawa, Yu-suke; Hamilton, Geraldine A; Kim, Hyun Jung; Ingber, Donald E

2012-06-21

Microscale engineering technologies provide unprecedented opportunities to create cell culture microenvironments that go beyond current three-dimensional in vitro models by recapitulating the critical tissue-tissue interfaces, spatiotemporal chemical gradients, and dynamic mechanical microenvironments of living organs. Here we review recent advances in this field made over the past two years that are focused on the development of 'Organs-on-Chips' in which living cells are cultured within microfluidic devices that have been microengineered to reconstitute tissue arrangements observed in living organs in order to study physiology in an organ-specific context and to develop specialized in vitro disease models. We discuss the potential of organs-on-chips as alternatives to conventional cell culture models and animal testing for pharmaceutical and toxicology applications. We also explore challenges that lie ahead if this field is to fulfil its promise to transform the future of drug development and chemical safety testing.

Summary of Adsorption Capacity and Adsorption Kinetics of Uranium and Other Elements on Amidoxime-based Adsorbents from Time Series Marine Testing at the Pacific Northwest National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.

The Pacific Northwest National Laboratory (PNNL) has been conducting marine testing of uranium adsorbent materials for the Fuel Resources Program, Department of Energy, Office of Nuclear Energy (DOE-NE) beginning in FY 2012. The marine testing program is being conducted at PNNL’s Marine Sciences Laboratory (MSL), located at Sequim Bay, along the coast of Washington. One of the main efforts of the marine testing program is the determination of adsorption capacity and adsorption kinetics for uranium and selected other elements (e.g. vanadium, iron, copper, nickel, and zinc) for adsorbent materials provided primarily by Oak Ridge National Laboratory (ORNL), but also includesmore » other Fuel Resources Program participants. This report summarizes the major marine testing results that have been obtained to date using time series sampling for 42 to 56 days using either flow-through column or recirculating flume exposures. The major results are highlighted in this report, and the full data sets are appended as a series of Excel spreadsheet files. Over the four year period (2012-2016) that marine testing of amidoxime-based polymeric adsorbents was conducted at PNNL’s Marine Science Laboratory, there has been a steady progression of improvement in the 56-day adsorbent capacity from 3.30 g U/kg adsorbent for the ORNL 38H adsorbent to the current best performing adsorbent prepared by a collaboration between the University of Tennessee and ORNL to produce the adsorbent SB12-8, which has an adsorption capacity of 6.56 g U/kg adsorbent. This nearly doubling of the adsorption capacity in four years is a significant advancement in amidoxime-based adsorbent technology and a significant achievement for the Uranium from Seawater program. The achievements are evident when compared to the several decades of work conducted by the Japanese scientists beginning in the 1980’s (Kim et al., 2013). The best adsorbent capacity reported by the Japanese scientists was 3.2 g U/kg adsorbent for a 180 day deployment at temperatures between 15 and 25 °C (Kim et al., 2013) The majority of the capacities the Japanese scientists reported were less than 2 g U/kg adsorbent (Kim et al., 2013). Repeated time series measurements of a common formulation of amidoxime-based adsorbent, the ORNL AF series, by both flow-through column (3.91 ± 0.11 g U/kg adsorbent). and recirculating flume exposures (4.03 ± 0.12 g U/kg adsorbent) produced 56-day adsorption capacities that agreed extremely well. This excellent agreement generates confidence that the testing procedures are accurate and reliable, and, moreover, that the technology to produce the adsorbents is highly reliable and reproducible, lending additional confidence of the robustness and homogeneity of the production technology.« less

Carbon/Attapulgite Composites as Recycled Palm Oil-Decoloring and Dye Adsorbents

PubMed Central

Tian, Guangyan; Zhu, Yongfeng; Zong, Li; Kang, Yuru; Wang, Aiqin

2018-01-01

Activated clay minerals have been widely used in the edible oil refining industry for decolorization of crude oil by adsorption, and so far many methods have been used to improve their decolorization efficiency. Herein, we successfully prepared a series of carbon/attapulgite (C/APT) composite adsorbents by a one-step in-situ carbonization process with natural starch (St) as the carbon source. It has been revealed that the adsorbent had better decolorization efficiency for crude palm oil than acid-activated APT. However, more than a million tons of decolorized waste is produced every year in the oil-refining industry, which was often treated as solid waste and has not yet been reutilized effectively. In order to explore a viable method to recycle and reuse the decolorant, the waste decolorant was further prepared into new C/APT adsorbents for the removal of dyes from wastewater, and then the dyes adsorbed on the adsorbent were used as the carbon sources to produce new C/APT adsorbents by a cyclic carbonization process. The results showed that the adsorbents prepared from the decolorized waste could remove more than 99.5% of the methylene blue (MB), methyl violet (MV), and malachite green (MG) dyes from the simulated wastewater with the dye concentration of 200 mg/L, and the C/APT–Re adsorbent consecutively regenerated five times using the adsorbed dyes as a carbon source still exhibit good adsorption efficiency for dyes. As a whole, this process opens a new avenue to develop efficient decolorants of palm oil and achieves recyclable utilization of decolored waste. PMID:29316634

Microengineered 3D cell-laden thermoresponsive hydrogels for mimicking cell morphology and orientation in cartilage tissue engineering.

PubMed

Mellati, Amir; Fan, Chia-Ming; Tamayol, Ali; Annabi, Nasim; Dai, Sheng; Bi, Jingxiu; Jin, Bo; Xian, Cory; Khademhosseini, Ali; Zhang, Hu

2017-01-01

Mimicking the zonal organization of native articular cartilage, which is essential for proper tissue functions, has remained a challenge. In this study, a thermoresponsive copolymer of chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) was synthesized as a carrier of mesenchymal stem cells (MSCs) to provide a support for their proliferation and differentiation. Microengineered three-dimensional (3D) cell-laden CS-g-PNIPAAm hydrogels with different microstripe widths were fabricated to control cellular alignment and elongation in order to mimic the superficial zone of natural cartilage. Biochemical assays showed six- and sevenfold increment in secretion of glycosaminoglycans (GAGs) and total collagen from MSCs encapsulated within the synthesized hydrogel after 28 days incubation in chondrogenic medium. Chondrogenic differentiation was also verified qualitatively by histological and immunohistochemical assessments. It was found that 75 ± 6% of cells encapsulated within 50 μm wide microstripes were aligned with an aspect ratio of 2.07 ± 0.16 at day 5, which was more organized than those observed in unpatterned constructs (12 ± 7% alignment and a shape index of 1.20 ± 0.07). The microengineered constructs mimicked the cell shape and organization in the superficial zone of cartilage whiles the unpatterned one resembled the middle zone. Our results suggest that microfabrication of 3D cell-laden thermosensitive hydrogels is a promising platform for creating biomimetic structures leading to more successful multi-zonal cartilage tissue engineering. Biotechnol. Bioeng. 2017;114: 217-231. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Selective Sorbents For Purification Of Hydrocarbons

DOEpatents

Yang, Ralph T.; Yang, Frances H.; Takahashi, Akira; Hernandez-Maldonado, Arturo J.

2006-04-18

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal ion that is adapted to form p-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by p-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Selective sorbents for purification of hydrocarbons

DOEpatents

Yang, Ralph T.; Hernandez-Maldonado, Arturo J.; Yang, Frances H.; Takahashi, Akira

2006-08-22

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal cation that is adapted to form .pi.-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by .pi.-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Selective sorbents for purification of hydrocarbons

DOEpatents

Yang, Ralph T.; Yang, Frances H.; Takahashi, Akira; Hernandez-Maldonado, Arturo J.

2006-05-30

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal cation that is adapted to form .pi.-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by .pi.-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Selective sorbents for purification of hydrocartons

DOEpatents

Yang, Ralph T.; Yang, Frances H.; Takahashi, Akira; Hermandez-Maldonado, Arturo J.

2006-12-12

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal ion that is adapted to form .pi.-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by .pi.-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Catalytic growth of carbon nanofibers on Cr nanoparticles on a carbon substrate: adsorbents for organic dyes in water

NASA Astrophysics Data System (ADS)

de Oliveira, Luiz Carlos Alves; da Silva, Adilson Cândido; Machado, Alan Rodrigues Teixeira; Diniz, Renata; Pereira, Márcio César

2013-05-01

We have produced carbon nanofibers (CNFs) using leather waste that had been tanned with a chromium bath, and when dried contained Cr2O3. Suitable reduction processing produced a carbon substrate with supported nanoparticles of chromium metal. Powder X-ray diffraction showed that the Cr2O3 is reduced on the carbon surface to produce CrC and metal Cr, which is the effective catalyst for the CNFs growth. The CNF arrays were confirmed by TEM images. Raman data revealed that the synthesized CNFs have a poor-quality graphite structure which favors their use in adsorption processes. These CNFs presented higher affinity to adsorb anionic dyes, whereas the cationic dyes are better adsorbed on the carbon substrate. The low-cost and availability of the carbon precursor makes their potential use to produce CNFs of interest.

Physico-chemical properties of biodiesel manufactured from waste frying oil using domestic adsorbents

PubMed Central

Ismail, Samir Abd-elmonem A; Ali, Rehab Farouk M

2015-01-01

We have evaluated the efficiency of sugar cane bagasse ash (SCBA), date palm seed carbon (DPSC), and rice husk ash (RHA) as natural adsorbents and compared them with the synthetic adsorbent Magnesol XL for improving the quality of waste frying oil (WFO) and for the impact on the physicochemical properties of the obtained biodiesel. We measured moisture content, refractive index (RI), density, acid value (AV), iodine value (IV), peroxide value (PV), and saponification value (SV), as well as fatty acid profile. Purification treatments with various levels of adsorbents caused significant (P ≤ 0.05) decreases in free fatty acids (FFAs), PVs, and IVs. The highest yields (86.45 and 87.80%) were observed for biodiesel samples produced from WFO treated with 2% Magnesol and 3% of RHA, respectively, followed by samples treated with 2 and 3% of DPSC or RHA. Pre-treatments caused a significant decrease in the content of C 18:2 linoleic acids, consistent with a significant increase in the content of monounsaturated and saturated fatty acids (MUFA) in the treated samples. The highest oxidation value (COX) (1.30) was observed for biodiesel samples produced from WFO without purification treatments. However, the lowest values (0.44–0.73) were observed for biodiesel samples produced from WFO treated with different levels of adsorbents. Our results indicate that pre-treatments with different levels of adsorbents regenerated the quality of WFO and improved the quality of the obtained biodiesel. PMID:27877789

Physico-chemical properties of biodiesel manufactured from waste frying oil using domestic adsorbents

NASA Astrophysics Data System (ADS)

Ismail, Samir Abd-elmonem A.; Ali, Rehab Farouk M.

2015-06-01

We have evaluated the efficiency of sugar cane bagasse ash (SCBA), date palm seed carbon (DPSC), and rice husk ash (RHA) as natural adsorbents and compared them with the synthetic adsorbent Magnesol XL for improving the quality of waste frying oil (WFO) and for the impact on the physicochemical properties of the obtained biodiesel. We measured moisture content, refractive index (RI), density, acid value (AV), iodine value (IV), peroxide value (PV), and saponification value (SV), as well as fatty acid profile. Purification treatments with various levels of adsorbents caused significant (P ≤ 0.05) decreases in free fatty acids (FFAs), PVs, and IVs. The highest yields (86.45 and 87.80%) were observed for biodiesel samples produced from WFO treated with 2% Magnesol and 3% of RHA, respectively, followed by samples treated with 2 and 3% of DPSC or RHA. Pre-treatments caused a significant decrease in the content of C 18:2 linoleic acids, consistent with a significant increase in the content of monounsaturated and saturated fatty acids (MUFA) in the treated samples. The highest oxidation value (COX) (1.30) was observed for biodiesel samples produced from WFO without purification treatments. However, the lowest values (0.44-0.73) were observed for biodiesel samples produced from WFO treated with different levels of adsorbents. Our results indicate that pre-treatments with different levels of adsorbents regenerated the quality of WFO and improved the quality of the obtained biodiesel.

Process for producing an activated carbon adsorbent with integral heat transfer apparatus

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Yavrouian, Andre H. (Inventor)

1996-01-01

A process for producing an integral adsorbent-heat exchanger apparatus useful in ammonia refrigerant heat pump systems. In one embodiment, the process wets an activated carbon particles-solvent mixture with a binder-solvent mixture, presses the binder wetted activated carbon mixture on a metal tube surface and thereafter pyrolyzes the mixture to form a bonded activated carbon matrix adjoined to the tube surface. The integral apparatus can be easily and inexpensively produced by the process in large quantities.

Production of capsular polysaccharide of Streptococcus pneumoniae type 14 and its purification by affinity chromatography.

PubMed

Suárez, N; Fraguas, L F; Texeira, E; Massaldi, H; Batista-Viera, F; Ferreira, F

2001-02-01

We describe a rapid and efficient method for producing the capsular polysaccharide of Streptococcus pneumoniae by fermentation on tryptic soy broth and purification of this compound by using immobilized soybean lectin as an affinity adsorbent. In principle, the same strategy can be used to produce purified capsular polysaccharides from other streptococcal serotypes by selecting the appropriate lectin adsorbents.

Production of Capsular Polysaccharide of Streptococcus pneumoniae Type 14 and Its Purification by Affinity Chromatography

PubMed Central

Suárez, Norma; Fraguas, Laura Franco; Texeira, Esther; Massaldi, Hugo; Batista-Viera, Francisco; Ferreira, Fernando

2001-01-01

We describe a rapid and efficient method for producing the capsular polysaccharide of Streptococcus pneumoniae by fermentation on tryptic soy broth and purification of this compound by using immobilized soybean lectin as an affinity adsorbent. In principle, the same strategy can be used to produce purified capsular polysaccharides from other streptococcal serotypes by selecting the appropriate lectin adsorbents. PMID:11157270

Microengineered embryonic stem cells niche to induce neural differentiation.

PubMed

Joshi, Ramila; Tavana, Hossein

2015-08-01

A major challenge in therapeutic use of embryonic stem cells (ESCs) for treating neurodegenerative diseases is creating a niche in vitro for controlled neural-specific differentiation of ESCs. We employ a niche microengineering approach to derive neural cells from ESCs by mimicking embryonic development in terms of direct intercellular interactions. Using a polymeric aqueous two-phase system (ATPS) microprinting technology, murine ESCs (mESCs) are precisely localized over a monolayer of supporting stromal cells to allow formation of individual mESC colonies. Polyethylene glycol (PEG) and dextran (DEX) are dissolved in culture media to form two immiscible aqueous solutions. A robotic liquid handler is used to print a nanoliter-volume drop of the denser DEX phase solution containing mESCs onto a confluent layer of supporting PA6 stromal cells submerged in the aqueous PEG phase. mESCs proliferate into isolated colonies of uniform size. For the first time, a comprehensive protein expression analysis of individual mESC colonies is performed over a two-week culture period to track temporal progression of cells from a pluripotent stage to specific neural cells. Starting from day 4, the expression of nestin, neural cell adhesion molecule (NCAM), and beta-III tubulin shows a significant increase but then levels off after the first week of culture. The expression of specific neural cell markers glial fibrillary acidic protein (GFAP), 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase), and tyrosine hydroxylase (TH) is elevated during the second week of culture. This microengineering approach to control ESCs differentiation niche combined with the time-course protein expression analysis of individual differentiating colonies facilitates understanding of evolution of specific neural cells from ESCs and identifying underlying molecular markers.

Organ-on-a-Chip Systems: Microengineering to Biomimic Living Systems.

PubMed

Zheng, Fuyin; Fu, Fanfan; Cheng, Yao; Wang, Chunyan; Zhao, Yuanjin; Gu, Zhongze

2016-05-01

"Organ-on-a-chip" systems integrate microengineering, microfluidic technologies, and biomimetic principles to create key aspects of living organs faithfully, including critical microarchitecture, spatiotemporal cell-cell interactions, and extracellular microenvironments. This creative platform and its multiorgan integration recapitulating organ-level structures and functions can bring unprecedented benefits to a diversity of applications, such as developing human in vitro models for healthy or diseased organs, enabling the investigation of fundamental mechanisms in disease etiology and organogenesis, benefiting drug development in toxicity screening and target discovery, and potentially serving as replacements for animal testing. Recent advances in novel designs and examples for developing organ-on-a-chip platforms are reviewed. The potential for using this emerging technology in understanding human physiology including mechanical, chemical, and electrical signals with precise spatiotemporal controls are discussed. The current challenges and future directions that need to be pursued for these proof-of-concept studies are also be highlighted. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct acceleration of electrons by a CO2 laser in a curved plasma waveguide

PubMed Central

Yi, Longqing; Pukhov, Alexander; Shen, Baifei

2016-01-01

Laser plasma interaction with micro-engineered targets at relativistic intensities has been greatly promoted by recent progress in the high contrast lasers and the manufacture of advanced micro- and nano-structures. This opens new possibilities for the physics of laser-matter interaction. Here we propose a novel approach that leverages the advantages of high-pressure CO2 laser, laser-waveguide interaction, as well as micro-engineered plasma structure to accelerate electrons to peak energy greater than 1 GeV with narrow slice energy spread (~1%) and high overall efficiency. The acceleration gradient is 26 GV/m for a 1.3 TW CO2 laser system. The micro-bunching of a long electron beam leads to the generation of a chain of ultrashort electron bunches with the duration roughly equal to half-laser-cycle. These results open a way for developing a compact and economic electron source for diverse applications. PMID:27320197

Hippo/YAP-mediated rigidity-dependent motor neuron differentiation of human pluripotent stem cells

NASA Astrophysics Data System (ADS)

Sun, Yubing; Yong, Koh Meng Aw; Villa-Diaz, Luis G.; Zhang, Xiaoli; Chen, Weiqiang; Philson, Renee; Weng, Shinuo; Xu, Haoxing; Krebsbach, Paul H.; Fu, Jianping

2014-06-01

Our understanding of the intrinsic mechanosensitive properties of human pluripotent stem cells (hPSCs), in particular the effects that the physical microenvironment has on their differentiation, remains elusive. Here, we show that neural induction and caudalization of hPSCs can be accelerated by using a synthetic microengineered substrate system consisting of poly(dimethylsiloxane) micropost arrays (PMAs) with tunable mechanical rigidities. The purity and yield of functional motor neurons derived from hPSCs within 23 days of culture using soft PMAs were improved more than fourfold and tenfold, respectively, compared with coverslips or rigid PMAs. Mechanistic studies revealed a multi-targeted mechanotransductive process involving Smad phosphorylation and nucleocytoplasmic shuttling, regulated by rigidity-dependent Hippo/YAP activities and actomyosin cytoskeleton integrity and contractility. Our findings suggest that substrate rigidity is an important biophysical cue influencing neural induction and subtype specification, and that microengineered substrates can thus serve as a promising platform for large-scale culture of hPSCs.

Tribochemical synthesis of nano-lubricant films from adsorbed molecules at sliding solid interface: Tribo-polymers from α-pinene, pinane, and n-decane

NASA Astrophysics Data System (ADS)

He, Xin; Barthel, Anthony J.; Kim, Seong H.

2016-06-01

The mechanochemical reactions of adsorbed molecules at sliding interfaces were studied for α-pinene (C10H16), pinane (C10H18), and n-decane (C10H22) on a stainless steel substrate surface. During vapor phase lubrication, molecules adsorbed at the sliding interface could be activated by mechanical shear. Under the equilibrium adsorption condition of these molecules, the friction coefficient of sliding steel surfaces was about 0.2 and a polymeric film was tribochemically produced. The synthesis yield of α-pinene tribo-polymers was about twice as much as pinane tribo-polymers. In contrast to these strained bicyclic hydrocarbons, n-decane showed much weaker activity for tribo-polymerization at the same mechanical shear condition. These results suggested that the mechanical shear at tribological interfaces could induce the opening of the strained ring structure of α-pinene and pinane, which leads to polymerization of adsorbed molecules at the sliding track. On a stainless steel surface, such polymerization reactions of adsorbed molecules do not occur under typical surface reaction conditions. The mechanical properties and boundary lubrication efficiency of the produced tribo-polymer films are discussed.

High performance of a unique mesoporous polystyrene-based adsorbent for blood purification

PubMed Central

Chen, Jian; Han, Wenyan; Chen, Jie; Zong, Wenhui; Wang, Weichao; Wang, Yue; Cheng, Guanghui; Li, Chunran; Ou, Lailiang; Yu, Yaoting

2017-01-01

A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as β2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient. PMID:28149527

High performance of a unique mesoporous polystyrene-based adsorbent for blood purification.

PubMed

Chen, Jian; Han, Wenyan; Chen, Jie; Zong, Wenhui; Wang, Weichao; Wang, Yue; Cheng, Guanghui; Li, Chunran; Ou, Lailiang; Yu, Yaoting

2017-02-01

A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as β2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient.

Development of a computationally-designed polymeric adsorbent specific for mycotoxin patulin.

PubMed

Piletska, Elena V; Pink, Demi; Karim, Kal; Piletsky, Sergey A

2017-12-04

Patulin is a toxic compound which is found predominantly in apples affected by mould rot. Since apples and apple-containing products are a popular food for the elderly, children and babies, the monitoring of the toxin is crucial. This paper describes a development of a computationally-designed polymeric adsorbent for the solid-phase extraction of patulin, which provides an effective clean-up of the food samples and allows the detection and accurate quantification of patulin levels present in apple juice using conventional chromatography methods. The developed bespoke polymer demonstrates a quantitative binding towards the patulin present in undiluted apple juice. The polymer is inexpensive and easy to mass-produce. The contributing factors to the function of the adsorbent is a combination of acidic and basic functional monomers producing a zwitterionic complex in the solution that formed stronger binding complexes with the patulin molecule. The protocols described in this paper provide a blueprint for the development of polymeric adsorbents for other toxins or different food matrices.

The Interaction of Carbon Monoxide with Rhodium on Potassium-Modified CeO 2(111)

DOE PAGES

Mullins, David R.

2016-02-03

The adsorption and reactions of CO adsorbed on Rh particles deposited on K-covered CeO 2(111) were studied by temperature programmed desorption and photoelectron spectroscopy. K deposited on CeO 2(111) forms a KO X over-layer by extracting O from the ceria and partially reducing some of the Ce 4+ to Ce 3+. CO does not adsorb on the KO X / CeO 2-X(111) surface in the absence of Rh particles. CO adsorbed on Rh / K / CeO 2(111) adsorbs molecularly on the Rh at 200 K. As the surface is heated the CO spills-over and reacts with the KOX tomore » form carbonate. The carbonate decomposes at elevated temperature to produce CO and CO 2. The carbonate stabilizes the KO X so that K desorbs at a higher temperature than it would in the absence of CO. When the Rh and K deposition are reversed so that K is deposited on both the Rh and the CeO 2(111), CO adsorbs as CO 2- at 200 K. The CO 2- decomposes below 350 K to produce gas phase CO and adsorbed CO3 2- and CO. The CO is stabilized by the K on the Rh and desorbs above 540 K. The carbonate decomposes into gas phase CO and CO 2.« less

A Microelectromechanical High-Density Energy Storage/Rapid Release System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, M. Steven; Allen, Jim J.; Meeks, Kent D.

1999-07-21

One highly desirable characteristic of electrostatically driven microelectromechanical systems (MEMS) is that they consume very little power. The corresponding drawback is that the force they produce may be inadequate for many applications. It has previously been demonstrated that gear reduction units or microtransmissions can substantially increase the torque generated by microengines. Operating speed, however, is also reduced by the transmission gear ratio. Some applications require both high speed and high force. If this output is only required for a limited period of time, then energy could be stored in a mechanical system and rapidly released upon demand. We have designed,more » fabricated, and demonstrated a high-density energy storage/rapid release system that accomplishes this task. Built using a 5-level surface micromachining technology, the assembly closely resembles a medieval crossbow. Energy releases on the order of tens of nanojoules have already been demonstrated, and significantly higher energy systems are under development.« less

Microelectromechanical high-density energy storage/rapid release system

NASA Astrophysics Data System (ADS)

Rodgers, M. Steven; Allen, James J.; Meeks, Kent D.; Jensen, Brian D.; Miller, Samuel L.

1999-08-01

One highly desirable characteristic of electrostatically driven microelectromechanical systems (MEMS) is that they consume very little power. The corresponding drawback is that the force they produce may be inadequate for many applications. It has previously been demonstrated that gear reduction units or microtransmissions can substantially increase the torque generated by microengines. Operating speed, however, is also reduced by the transmission gear ratio. Some applications require both high speed and high force. If this output is only required for a limited period of time, then energy could be stored in a mechanical system and rapidly released upon demand. We have designed, fabricated, and demonstrated a high-density energy storage/rapid release system that accomplishes this task. Built using a 5-level surface micromachining technology, the assembly closely resembles a medieval crossbow. Energy releases on the order of tens of nanojoules have already been demonstrated, and significantly higher energy systems are under development.

Modeling adsorption: Investigating adsorbate and adsorbent properties

NASA Astrophysics Data System (ADS)

Webster, Charles Edwin

1999-12-01

Surface catalyzed reactions play a major role in current chemical production technology. Currently, 90% of all chemicals are produced by heterogeneously catalyzed reactions. Most of these catalyzed reactions involve adsorption, concentrating the substrate(s) (the adsorbate) on the surface of the solid (the adsorbent). Pore volumes, accessible surface areas, and the thermodynamics of adsorption are essential in the understanding of solid surface characteristics fundamental to catalyst and adsorbent screening and selection. Molecular properties such as molecular volumes and projected molecular areas are needed in order to convert moles adsorbed to surface volumes and areas. Generally, these molecular properties have been estimated from bulk properties, but many assumptions are required. As a result, different literature values are employed for these essential molecular properties. Calculated molar volumes and excluded molecular areas are determined and tabulated for a variety of molecules. Molecular dimensions of molecules are important in the understanding of molecular exclusion as well as size and shape selectivity, diffusion, and adsorbent selection. Molecular dimensions can also be used in the determination of the effective catalytic pore size of a catalyst. Adsorption isotherms, on zeolites, (crystalline mineral oxides) and amorphous solids, can be analyzed with the Multiple Equilibrium Analysis (MEA) description of adsorption. The MEA produces equilibrium constants (Ki), capacities (ni), and thermodynamic parameters (enthalpies, ΔHi, and entropies, ΔSi) of adsorption for each process. Pore volumes and accessible surface areas are calculated from the process capacities. Adsorption isotherms can also be predicted for existing and new adsorbate-adsorbent systems with the MEA. The results show that MEA has the potential of becoming a standard characterization method for microporous solids that will lead to an increased understanding of their behavior in gas adsorption and catalysis. These studies are also applicable to environmental cleanup applications, such as waste stream purification and separation procedures as well as decontamination of chemical warfare agents.

Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime-Based Adsorbents in Natural Seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, Li-Jung; Gill, Gary A.; Tsouris, Costas

Recent advances in the development of amidoxime-based adsorbents have made it highly promising for seawater uranium extraction. However, there is a great need to understand the influence of temperature on the uranium sequestration performance of the adsorbents in natural seawater. Here in this work, the apparent enthalpy and entropy of the sorption of uranium (VI) and vanadium (V) with amidoxime-based adsorbents were determined in natural seawater tests at 8, 20, and 31 °C that cover a broad range of ambient seawater temperature. The sorption of U was highly endothermic, producing apparent enthalpies of 57 ± 6.0 and 59 ± 11more » kJ mol -1 and apparent entropies of 314 ± 21 and 320 ± 36 J K-1 mol -1, respectively, for two adsorbent formulations. In contrast, the sorption of V showed a much smaller temperature sensitivity, producing apparent enthalpies of 6.1 ± 5.9 and -11 ± 5.7 kJ mol -1 and apparent entropies of 164 ± 20 and 103 ± 19 J K -1 mol -1, respectively. This new thermodynamic information suggests that amidoxime-based adsorbents will deliver significantly increased U adsorption capacities and improved selectivity in warmer waters. A separate field study of seawater uranium adsorption conducted in a warm seawater site (Miami, FL, USA) confirm the observed strong temperature effect on seawater uranium mining. Lastly, this strong temperature dependence demonstrates that the warmer the seawater where the amidoxime-based adsorbents are deployed the greater the yield for seawater uranium extraction.« less

Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime-Based Adsorbents in Natural Seawater

DOE PAGES

Kuo, Li-Jung; Gill, Gary A.; Tsouris, Costas; ...

2018-01-16

Recent advances in the development of amidoxime-based adsorbents have made it highly promising for seawater uranium extraction. However, there is a great need to understand the influence of temperature on the uranium sequestration performance of the adsorbents in natural seawater. Here in this work, the apparent enthalpy and entropy of the sorption of uranium (VI) and vanadium (V) with amidoxime-based adsorbents were determined in natural seawater tests at 8, 20, and 31 °C that cover a broad range of ambient seawater temperature. The sorption of U was highly endothermic, producing apparent enthalpies of 57 ± 6.0 and 59 ± 11more » kJ mol -1 and apparent entropies of 314 ± 21 and 320 ± 36 J K-1 mol -1, respectively, for two adsorbent formulations. In contrast, the sorption of V showed a much smaller temperature sensitivity, producing apparent enthalpies of 6.1 ± 5.9 and -11 ± 5.7 kJ mol -1 and apparent entropies of 164 ± 20 and 103 ± 19 J K -1 mol -1, respectively. This new thermodynamic information suggests that amidoxime-based adsorbents will deliver significantly increased U adsorption capacities and improved selectivity in warmer waters. A separate field study of seawater uranium adsorption conducted in a warm seawater site (Miami, FL, USA) confirm the observed strong temperature effect on seawater uranium mining. Lastly, this strong temperature dependence demonstrates that the warmer the seawater where the amidoxime-based adsorbents are deployed the greater the yield for seawater uranium extraction.« less

Applications of laser ablation to microengineering

NASA Astrophysics Data System (ADS)

Gower, Malcolm C.; Rizvi, Nadeem H.

2000-08-01

Applications of pulsed laser ablation to the manufacture of micro- electro-mechanical systems (MEMS) and micro-opto-electro-mechanical systems (MOEMS) devices are presented. Laser ablative processes used to manufacture a variety of microsystems technology (MST) components in the computer peripheral, sensing and biomedical industries are described together with a view of some future developments.

Near-infrared light-triggered "on/off" motion of polymer multilayer rockets.

PubMed

Wu, Zhiguang; Lin, Xiankun; Wu, Yingjie; Si, Tieyan; Sun, Jianmin; He, Qiang

2014-06-24

We describe an approach to modulating the on-demand motion of catalytic polymer-based microengines via near-infrared (NIR) laser irradiation. The polymer multilayer motor was fabricated by the template-assisted layer-by-layer assembly and subsequently deposition of platinum nanoparticles inside and a thin gold shell outside. Then a mixed monolayer of a tumor-targeted peptide and an antifouling poly(ethylene glycol) was functionalized on the gold shell. The microengines remain motionless at the critical peroxide concentration (0.1%, v/v); however, NIR illumination on the engines leads to a photothermal effect and thus rapidly triggers the motion of the catalytic engines. Computational modeling explains the photothermal effect and gives the temperature profile accordingly. Also, the photothermal effect can alone activate the motion of the engines in the absence of the peroxide fuel, implying that it may eliminate the use of toxic fuel in the future. The targeted recognition ability and subsequently killing of cancer cells by the photothermal effect under the higher power of a NIR laser were illustrated. Our results pave the way to apply self-propelled synthetic engines in biomedical fields.

Measurements and analyses of principal dynamic parameters of building structures as a function of type of vibration excitation

NASA Astrophysics Data System (ADS)

Bartmański, Cezary; Bochenek, Wojciech; Passia, Henryk; Szade, Adam

2006-06-01

The methods of direct measurement and analysis of the dynamic response of a building structure through real-time recording of the amplitude of low-frequency vibration (tilt) have been presented. Subject to analyses was the reaction induced either by kinematic excitation (road traffic and mining-induced vibration) or controlled action of solid-fuel rocket micro-engines installed on the building. The forces were analysed by means of a set of transducers installed both in the ground and on the structure. After the action of excitation forces has been stopped, the system (structure) makes damped vibration around the static equilibrium position. It has been shown that the type of excitation affects the accuracy of evaluation of principal dynamic parameters of the structure. In the authors opinion these are the decrement of damping and natural vibration frequency. Positive results of tests with the use of excitation by means of short-action (0.6 second) rocket micro-engines give a chance to develop a reliable method for periodical assessment of acceptable loss of usability characteristics of building structures heavily influenced by environmental effects.

Mechanical characterization of bulk Sylgard 184 for microfluidics and microengineering

NASA Astrophysics Data System (ADS)

Johnston, I. D.; McCluskey, D. K.; Tan, C. K. L.; Tracey, M. C.

2014-03-01

Polydimethylsiloxane (PDMS) elastomers are extensively used for soft lithographic replication of microstructures in microfluidic and micro-engineering applications. Elastomeric microstructures are commonly required to fulfil an explicit mechanical role and accordingly their mechanical properties can critically affect device performance. The mechanical properties of elastomers are known to vary with both curing and operational temperatures. However, even for the elastomer most commonly employed in microfluidic applications, Sylgard 184, only a very limited range of data exists regarding the variation in mechanical properties of bulk PDMS with curing temperature. We report an investigation of the variation in the mechanical properties of bulk Sylgard 184 with curing temperature, over the range 25 °C to 200 °C. PDMS samples for tensile and compressive testing were fabricated according to ASTM standards. Data obtained indicates variation in mechanical properties due to curing temperature for Young's modulus of 1.32-2.97 MPa, ultimate tensile strength of 3.51-7.65 MPa, compressive modulus of 117.8-186.9 MPa and ultimate compressive strength of 28.4-51.7 GPa in a range up to 40% strain and hardness of 44-54 ShA.

Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications.

PubMed

Gao, Bin; Wang, Lin; Han, Shuang; Pingguan-Murphy, Belinda; Zhang, Xiaohui; Xu, Feng

2016-08-01

Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.

EDITORIAL: 16th European Workshop on Micromechanics (MME 2005)

NASA Astrophysics Data System (ADS)

Enoksson, Professor Peter

2006-06-01

This special issue of Journal of Micromechanics and Microengineering is devoted to the 16th European Workshop on Micromechanics (MME 2005), which was held in Göteborg, Sweden, at the Chalmers Conference Centre on the premises of Chalmers University of Technology, 4-6 September 2005. Göteborg is the second largest city in Sweden and is situated on the beautiful south-west coast. With its relaxed and friendly atmosphere Göteborg proudly lives up to its reputation of having the charm of a small town with all the opportunities of a big city. The MME workshop is a well recognized and established European event for creating microsensors and microactuators in the field of micromachining, microengineering and technology. The very first workshop was held at Twente University, The Netherlands, in 1989. Scientists and people from industry who are interested in the field gather annually for this event. The goals are stimulation and improvement of know-how in the field, as well as establishing cooperation and friendship between delegates. Thus MME is arranged so that people can meet in a friendly and informal atmosphere. That is why the accent is on mutual discussions around poster presentations rather than on formal oral presentations. The contributions, which came from 21 countries, were presented in four sessions and five keynote presentations. I am proud to present 24 high-quality papers from MME 2005 selected for their novelty and relevance to Journal of Micromechanics and Microengineering. Each paper passed a rigorous peer review process. May I take this opportunity to thank those authors who contributed their research to this special issue, which I hope gives an excellent overview of topics discussed at the workshop. I would also like to express my gratitude to Professor Robert Puers for advising on the selection of papers and to Dr Anke Sanz-Velasco for helping to coordinate the special issue with the Institute of Physics Publishing office at the start. I hope you enjoy reading this selection of papers.

Editorial

NASA Astrophysics Data System (ADS)

Puers, R.

2007-01-01

As we enter the 2007 volume of Journal of Micromechanics and Microengineering, the journal's seventeenth, I would like to take the opportunity to reflect on the achievements of the past year. The considerable increase in submissions to the journal, as you all may have noticed by the steadily increasing volume, is the most visible change. A total of 3272 pages were published in 2006, an increase of 12% on 2005. More exciting, and maybe less noticeable, is that the journal's ISI® impact factor saw a significant increase to 2.499. This is an achievement we can all be proud of. If the journal and its impact factor are growing, it is only because more of you are choosing to submit your high-quality work to the journal, and because more of you are choosing to refer to recent papers published within the journal! I would like to take this opportunity to thank each of you, readers, authors and referees alike. The large amount of submitted articles has naturally had a considerable impact on the number of referees. In 2006 around 750 experts agreed to our requests to review. We have requested, and received, reports from at least 36 different countries. We would like to express our thanks to all of our referees for their careful and well constructed reports which are of great assistance in maintaining the rigorous quality standards of Journal of Micromechanics and Microengineering. All this would not of course be possible without the constant influx of magnificent papers dealing with the many fascinating aspects of microengineering and micromachining. I believe we have achieved a clear and distinct profile in the broad spectrum of journals in this field, and it is my sincerest hope that we can even enhance this profile. This is of course unthinkable without the efforts of each individual researcher in our community. I therefore wish each of you a prosperous and adventurous 2007 in your quest to expand the frontiers in micromachining. Let's continue the path we have chosen.

FTIR study of methanol decomposition on gold catalyst for fuel cells

NASA Astrophysics Data System (ADS)

Boccuzzi, F.; Chiorino, A.; Manzoli, M.

The interaction of methanol (m), methanol-water (mw) and methanol-water-oxygen (mwo) on Au/TiO 2 catalyst has been investigated by in situ infrared spectroscopy (FTIR) and quadrupole mass spectrometry (QMS) at different temperatures. The aim of the work is to elucidate the nature and the abundance of the surface intermediates formed in different experimental conditions and to understand the mechanisms of methanol decomposition, of steam reforming and of combined reforming reactions. FTIR spectra run at room temperature in the different reaction mixtures show that differently coordinated methoxy species, that is on top species adsorbed on oxygen vacancy sites, on top species on uncoordinated Ti 4+ sites and bridged species on two Ti 4+ ions, are produced in all the mixtures. Quite strong formaldehyde and formate species adsorbed on gold are produced already at 403 K only in the combined reforming reaction mixture. At 473 K, on top species on uncoordinated Ti 4+ sites and methoxy species adsorbed on oxygen vacancy sites reduce their intensity and, at the same time, some formate species adsorbed on the support are produced in the steam reforming and combined reforming mixtures. At 523 K, on both methanol and methanol-water reaction mixtures, no more definite surface species are evidenced by FTIR on the catalysts, while in the methanol-water-oxygen mixture some residual methoxy and formate species are still present. Moreover, methanol is no more detected by QMS in the gas phase. A role of oxygen adsorbed on gold particles near oxygen vacancies of the support in the oxidative dehydrogenation of methanol is proposed.

Adsorption of cadmium by biochar produced from pyrolysis of corn stalk in aqueous solution.

PubMed

Ma, Fengfeng; Zhao, Baowei; Diao, Jingru

2016-09-01

The purpose of this work is to investigate adsorption characteristic of corn stalk (CS) biochar for removal of cadmium ions (Cd 2+ ) from aqueous solution. Batch adsorption experiments were carried out to evaluate the effects of pH value of solution, adsorbent particle size, adsorbent dosage, and ionic strength of solution on the adsorption of Cd 2+ onto biochar that was pyrolytically produced from CS at 300 °C. The results showed that the initial pH value of solution played an important role in adsorption. The adsorptive amount of Cd 2+ onto the biochar decreased with increasing the adsorbent dosage, adsorbent particle size, and ionic strength, while it increased with increasing the initial pH value of solution and temperature. Cd 2+ was removed efficiently and quickly from aqueous solutions by the biochar with a maximum capacity of 33.94 mg/g. The adsorption process was well described by the pseudo-second-order kinetic model with the correlation coefficients greater than 0.986. The adsorption isotherm could be well fitted by the Langmuir model. The thermodynamic studies showed that the adsorption of Cd 2+ onto the biochar was a spontaneous and exothermic process. The results indicate that CS biochar can be considered as an efficient adsorbent.

Preparation of activated petroleum coke for removal of naphthenic acids model compounds: Box-Behnken design optimization of KOH activation process.

PubMed

Niasar, Hojatallah Seyedy; Li, Hanning; Das, Sreejon; Kasanneni, Tirumala Venkateswara Rao; Ray, Madhumita B; Xu, Chunbao Charles

2018-04-01

This study employed Box-Behnken design and response surface methodology to optimize activation parameters for the production of activated petroleum coke (APC) adsorbent from petroleum coke (PC) to achieve highest adsorption capacity for three model naphthenic acids. Activated petroleum coke (APC) adsorbent with a BET surface area of 1726 m 2 /g and total pore volume of 0.85 cc/g was produced at the optimum activation conditions (KOH/coke mass ratio) of 3.0, activation temperature 790 °C, and activation time 3.47 h). Effects of the activation parameters on the adsorption pefromances (adsortion capaciy and kinetics) were investigated. With the APC obtained at the optimum activation condition, the maximum adsorption capacity of 451, 362, and 320 (mg/g) was achieved for 2-naphthoic acid, diphenylacetic acid and cyclohexanepentanoic acid (CP), respectively. Although, generally APC adsorbents with a higher specific surface area and pore volume provide better adsorption capacity, the textural properties (surface areas and pore volume) are not the only parameters determining the APC adsorbents' adsorption capacity. Other parameters such as surface functionalities play effective roles on the adsorption capacity of the produced APC adsorbents for NAs. The KOH activation process, in particular the acid washing step, distinctly reduced the sulfur and metals contents in the raw PC, decreasing the leaching potential of metals from APC adsorbents during adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method of recovering adsorbed liquid compounds from molecular sieve columns

DOEpatents

Burkholder, H.R.; Fanslow, G.E.

1983-12-20

Molecularly adsorbed volatile liquid compounds are recovered from molecular sieve adsorbent columns by directionally applying microwave energy to the bed of the adsorbent to produce a mixed liquid-gas effluent. The gas portion of the effluent generates pressure within the bed to promote the discharge of the effluent from the column bottoms. Preferably the discharged liquid-gas effluent is collected in two to three separate fractions, the second or intermediate fraction having a substantially higher concentration of the desorbed compound than the first or third fractions. The desorption does not need to be assisted by passing a carrier gas through the bed or by applying reduced pressure to the outlet from the bed. 8 figs.

Method of recovering adsorbed liquid compounds from molecular sieve columns

DOEpatents

Burkholder, Harvey R.; Fanslow, Glenn E.

1983-01-01

Molecularly adsorbed volatile liquid compounds are recovered from molecular sieve adsorbent columns by directionally applying microwave energy to the bed of the adsorbent to produce a mixed liquid-gas effluent. The gas portion of the effluent generates pressure within the bed to promote the discharge of the effluent from the column bottoms. Preferably the discharged liquid-gas effluent is collected in two to three separate fractions, the second or intermediate fraction having a substantially higher concentration of the desorbed compound than the first or third fractions. The desorption does not need to be assisted by passing a carrier gas through the bed or by applying reduced pressure to the outlet from the bed.

Biomass based activated carbon obtained from sludge and sugarcane bagasse for removing lead ion from wastewater.

PubMed

Tao, Hu-Chun; Zhang, He-Ran; Li, Jin-Bo; Ding, Wen-Yi

2015-09-01

Sewage sludge and bagasse were used as raw materials to produce cheap and efficient adsorbent with great adsorption capacity of Pb(2+). By pyrolysis at 800 °C for 0.5 h, the largest surface area (806.57 m(2)/g) of the adsorbent was obtained, enriched with organic functional groups. The optimal conditions for production of the adsorbent and adsorption of Pb(2+) were investigated. The results of adsorb-ability fitted the Langmuir isotherm and pseudo-second-order model well. The highest Pb(2+) (at pH = 4.0) adsorption capacity was achieved by treating with 60% (v/v) HNO3. This is a promising approach for metal removal from wastewater, as well as recycling sewage sludge and bagasse to ease their disposal pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Catalase-like activity studies of the manganese(II) adsorbed zeolites

NASA Astrophysics Data System (ADS)

ćiçek, Ekrem; Dede, Bülent

2013-12-01

Preparation of manganese(II) adsorbed on zeolite 3A, 4A, 5A. AW-300, ammonium Y zeolite, organophilic, molecular sieve and catalase-like enzyme activity of manganese(II) adsorbed zeolites are reported herein. Firstly zeolites are activated at 873 K for two hours before contact manganese(II) ions. In order to observe amount of adsorption, filtration process applied for the solution. The pure zeolites and manganese(II) adsorbed zeolites were analysed by FT-IR. As a result according to the FT-IR spectra, the incorporation of manganese(II) cation into the zeolite structure causes changes in the spectra. These changes are expected particularly in the pseudolattice bands connected with the presence of alumino and silicooxygen tetrahedral rings in the zeolite structure. Furthermore, the catalytic activities of the Mn(II) adsorbed zeolites for the disproportionation of hydrogen peroxide were investigated in the presence of imidazole. The Mn(II) adsorbed zeolites display efficiency in the disproportion reactions of hydrogen peroxide, producing water and dioxygen in catalase-like activity.

Fabrication of plastic microparts on wafer level

NASA Astrophysics Data System (ADS)

Weber, Lutz; Ehrfeld, Wolfgang; Begemann, Marc; Berg, Udo; Michel, Frank

1999-08-01

In the recent years micromolding has become one of the most important key technologies of microengineering. At the current state of art, the mass fabrication of plastic microparts for a wide range of applications like telecommunications, sensors, medical technology and biochemistry is feasible. Here a micro motor, plastic optical waveguides, a micro pump, and nanotiterplates are presented.

Prussian blue caged in spongiform adsorbents using diatomite and carbon nanotubes for elimination of cesium.

PubMed

Hu, Baiyang; Fugetsu, Bunshi; Yu, Hongwen; Abe, Yoshiteru

2012-05-30

We developed a spongiform adsorbent that contains Prussian blue, which showed a high capacity for eliminating cesium. An in situ synthesizing approach was used to synthesize Prussian blue inside diatomite cavities. Highly dispersed carbon nanotubes (CNTs) were used to form CNT networks that coated the diatomite to seal in the Prussian blue particles. These ternary (CNT/diatomite/Prussian-blue) composites were mixed with polyurethane (PU) prepolymers to produce a quaternary (PU/CNT/diatomite/Prussian-blue), spongiform adsorbent with an in situ foaming procedure. Prussian blue was permanently immobilized in the cell walls of the spongiform matrix and preferentially adsorbed cesium with a theoretical capacity of 167 mg/g cesium. Cesium was absorbed primarily by an ion-exchange mechanism, and the absorption was accomplished by self-uptake of radioactive water by the quaternary spongiform adsorbent. Copyright © 2012 Elsevier B.V. All rights reserved.

Biomass Potential of Virgin and Calcined Tapioca (Cassava Starch) for the Removal of Sr(II) and Cs(I) from Aqueous Solutions.

PubMed

Ogata, Fumihiko; Nagai, Noriaki; Ueta, Erimi; Nakamura, Takehiro; Kawasaki, Naohito

2018-01-01

In this study, we prepared novel adsorbents containing virgin and calcined tapioca products for removing strontium (Sr(II)) and cesium (Cs(I)) from aqueous solutions. The characteristics of tapioca, along with its capacity to adsorb Sr(II) and Cs(I), were evaluated. Multiple tapioca products were prepared and tested. The adsorbent prepared by boiling the tapioca followed by calcination at 300°C (BTP300) was the most effective. In addition, adsorption was affected by the adsorbent's surface properties. The Sr(II) and Cs(I) adsorbed onto BTP300 could be recovered through desorption by hydrochloric acid at different concentrations, which indicates that BTP300 can be used several times for adsorption/desorption. The results of this study suggest that BTP300, which was produced from tapioca biomass, can remove Sr(II) and Cs(I) from aqueous solutions.

Mobility of adsorbed Cry1Aa insecticidal toxin from Bacillus thuringiensis (Bt) on montmorillonite measured by fluorescence recovery after photobleaching (FRAP)

NASA Astrophysics Data System (ADS)

Helassa, Nordine; Daudin, Gabrielle; Noinville, Sylvie; Janot, Jean-Marc; Déjardin, Philippe; Staunton, Siobhán; Quiquampoix, Hervé

2010-06-01

The insecticidal toxins produced by genetically modified Bt crops are introduced into soil through root exudates and tissue decomposition and adsorb readily on soil components, especially on clays. This immobilisation and the consequent concentration of the toxins in "hot spots" could increase the exposure of soil organisms. Whereas the effects on non-target organisms are well documented, few studies consider the migration of the toxin in soil. In this study, the residual mobility of Bt Cry1Aa insecticidal toxin adsorbed on montmorillonite was assessed using fluorescence recovery after photobleaching (FRAP). This technique, which is usually used to study dynamics of cytoplasmic and membrane molecules in live cells, was applied for the first time to a protein adsorbed on a finely divided swelling clay mineral, montmorillonite. No mobility of adsorbed toxin was observed at any pH and at different degrees of surface saturation.

Application of thermal analysis techniques in activated carbon production

USGS Publications Warehouse

Donnals, G.L.; DeBarr, J.A.; Rostam-Abadi, M.; Lizzio, A.A.; Brady, T.A.

1996-01-01

Thermal analysis techniques have been used at the ISGS as an aid in the development and characterization of carbon adsorbents. Promising adsorbents from fly ash, tires, and Illinois coals have been produced for various applications. Process conditions determined in the preparation of gram quantities of carbons were used as guides in the preparation of larger samples. TG techniques developed to characterize the carbon adsorbents included the measurement of the kinetics of SO2 adsorption, the performance of rapid proximate analyses, and the determination of equilibrium methane adsorption capacities. Thermal regeneration of carbons was assessed by TG to predict the life cycle of carbon adsorbents in different applications. TPD was used to determine the nature of surface functional groups and their effect on a carbon's adsorption properties.

14 million hours of operational experience on phosphate ester fluids as gas turbine main bearing lubricants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dufresne, P.E.

1998-09-01

Phosphate ester fluids have been used as a gas turbine main bearing lubricant for more than 35 years. Acid treatment systems utilizing fullers` earth and activated alumina have been used to remove acids produced during the PE fluid degradation process on an intermittent or continuous basis. Both acid adsorbing medias contribute metal soaps during the acid adsorbing process. Over time, the build-up of metal soaps significantly reduces the capability of the media to adsorb acids. The end result is escalating acid levels and fluid operating problems. The introduction of ion exchange as an acid adsorbing media has eliminated the catalyticmore » fluid degradation process, and offers phosphate ester users` extremely long fluid service life.« less

Prospects of banana waste utilization in wastewater treatment: A review.

PubMed

Ahmad, Tanweer; Danish, Mohammed

2018-01-15

This review article explores utilization of banana waste (fruit peels, pseudo-stem, trunks, and leaves) as precursor materials to produce an adsorbent, and its application against environmental pollutants such as heavy metals, dyes, organic pollutants, pesticides, and various other gaseous pollutants. In recent past, quite a good number of research articles have been published on the utilization of low-cost adsorbents derived from biomass wastes. The literature survey on banana waste derived adsorbents shown that due to the abundance of banana waste worldwide, it also considered as low-cost adsorbents with promising future application against various environmental pollutants. Furthermore, raw banana biomass can be chemically modified to prepare efficient adsorbent as per requirement; chemical surface functional group modification may enhance the multiple uses of the adsorbent with industrial standard. It was evident from a literature survey that banana waste derived adsorbents have significant removal efficiency against various pollutants. Most of the published articles on banana waste derived adsorbents have been discussed critically, and the conclusion is drawn based on the results reported. Some results with poorly performed experiments were also discussed and pointed out their lacking in reporting. Based on literature survey, the future research prospect on banana wastes has a significant impact on upcoming research strategy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of zeolite from rice husk ash waste of brick industries as hydrophobic adsorbent for fuel grade ethanol purification

NASA Astrophysics Data System (ADS)

Purnomo, A.; Alhanif, M.; Khotimah, C.; Zuhra, UA; Putri, BR; Kumoro, AC

2017-11-01

A lot of researchers have devoted on ethanol utilization as renewable energy to substitute petroleum based gasoline. When ethanol is being used as a new fuel candidate, it should have at least of 99.5% purity. Usually produced via sugar fermentation process, further purification of ethanol from other components in fermentation broth to obtain its fuel grade is a crucial step. The purpose of this research is to produce synthetic zeolite as hydrophobic adsorbent from rice husk ash for ethanol-water separation and to investigate the influence of weight, adsorption time and initial ethanol concentration on zeolite adsorption capacity. This research consisted of rice husk silica extraction, preparation of hydrophobic zeolite adsorbent, physical characterization using SEM, EDX and adsorption test for an ethanol-water solution. Zeolite with highest adsorption capacity was obtained with 15: 1 alumina silica composition. The best adsorption condition was achieved when 4-gram hydrophobic zeolite applied for adsorption of 100 mL of 10% (v/v) ethanol-water solution for 120 minutes, which resulted in ethanol with 98.93% (v/v) purity. The hydrophobic zeolite from rice husk ash is a potential candidate as an efficient adsorbent to purify raw ethanol into fuel grade ethanol. Implementation of this new adsorbent for ethanol production in commercial scale may reduce the energy consumption of that usually used for the distillation processes.

The adsorption and thermal decomposition of PH 3 on Si(111)-(7 × 7)

NASA Astrophysics Data System (ADS)

Taylor, P. A.; Wallace, R. M.; Choyke, W. J.; Yates, J. T.

1990-11-01

The adsorption of PH 3, on Si(111)-(7 × 7) has been studied by Auger electron spectroscopy and temperature programmed desorption. PH 3 was found to exhibit two kinds of behavior on the surface. A small surface coverage of molecularly adsorbed PH 3 desorbs without any dissociative surface chemistry. For the majority of the adsorbed PH x species (3 ⩾ x ⩾ 1) dissociation occurs to form P(a) and H(a). At 120 K, PH 3 initially adsorbs as the reactive species with a sticking coefficient of S ≅ 1 up to ˜75% saturation. The reactive PH x species surface concentration saturates at (1.9 ± 0.3) × 10 14 PH x cm -2. Surface H(a), produc thermal decomposition, desorbs as H 2(g) at T > 700 K., and P(a) desorbs as P 2(g) at T > 900 K. Capping the Si-dangling bonds with atomic deuterium prevents PH 3 adsorption, indicating that the dangling bonds are the PH 3 adsorption sites. Isotopic studies involving Si-D surface species mixed with adsorbed PH x species indicate that PH 3 desorption does not occur through a recombination process. Finally, additional PH 3 may be adsorbed if the surface hydrogen produced by dissociation of PH 3 is removed. Evidence for P penetration into bulk Si(111) at 875 K is presented.

Electron shuttle-mediated biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine adsorbed to granular activated carbon.

PubMed

Millerick, Kayleigh; Drew, Scott R; Finneran, Kevin T

2013-08-06

Granular activated carbon (GAC) effectively removes hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from groundwater but generates RDX-laden GAC that must be disposed of or regenerated. Batch reactors containing GAC to which RDX was preadsorbed were used in experiments to test the potential for adsorbed RDX reduction and daughter product formation using (i) chemically reduced anthrahydroquinone-2,6-disulfonate (AH2QDS), (ii) resting Geobacter metallireducens strain GS-15, and (iii) a combined system containing AQDS and GS-15. Approximately 97.0% of the adsorbed RDX was transformed in each of these experimental systems by 90 h. Chemically reduced AQDS (AH2QDS) transformed 99.2% of adsorbed RDX; formaldehyde was produced rapidly and was stoichiometric (3 mol HCHO per mol RDX). Geobacter metallireducens also reduced RDX with and without AQDS present. This is the first study to demonstrate biological transformation of RDX adsorbed to GAC. Formaldehyde increased and then decreased in biological systems, suggesting a previously unreported capacity for G. metallireducens to oxidize formaldehyde, which was confirmed with resting cell suspensions. These data suggest the masses of GAC waste currently produced by activated carbon at RDX remediation sites can be minimized, decreasing the carbon footprint of the treatment technology. Alternatively, this strategy may be used to develop a Bio-GAC system for ex situ RDX treatment.

Comparison of ion coupling strategies for a microengineered quadrupole mass filter.

PubMed

Wright, Steven; Syms, Richard R A; O'Prey, Shane; Hong, Guodong; Holmes, Andrew S

2009-01-01

The limitations of conventional machining and assembly techniques require that designs for quadrupole mass analyzers with rod diameters less than a millimeter are not merely scale versions of larger instruments. We show how silicon planar processing techniques and microelectromechanical systems (MEMS) design concepts can be used to incorporate complex features into the construction of a miniature quadrupole mass filter chip that could not easily be achieved using other microengineering approaches. Three designs for the entrance and exit to the filter consistent with the chosen materials and techniques have been evaluated. The differences between these seemingly similar structures have a significant effect on the performance. Although one of the designs results in severe attenuation of transmission with increasing mass, the other two can be scanned to m/z = 400 without any corruption of the mass spectrum. At m/z = 219, the variation in the transmission of the three designs was found to be approximately four orders of magnitude. A maximum resolution of M/DeltaM = 87 at 10% peak height has been achieved at m/z = 219 with a filter operated at 6 MHz and constructed using rods measuring (508 +/- 5) microm in diameter.

A wearable pressure sensor based on ultra-violet/ozone microstructured carbon nanotube/polydimethylsiloxane arrays for electronic skins.

PubMed

Yu, Guohui; Hu, Jingdong; Tan, Jianping; Gao, Yang; Lu, Yongfeng; Xuan, Fuzhen

2018-03-16

Pressure sensors with high performance (e.g., a broad pressure sensing range, high sensitivities, rapid response/relaxation speeds, temperature-stable sensing), as well as a cost-effective and highly efficient fabrication method are highly desired for electronic skins. In this research, a high-performance pressure sensor based on microstructured carbon nanotube/polydimethylsiloxane arrays was fabricated using an ultra-violet/ozone (UV/O 3 ) microengineering technique. The UV/O 3 microengineering technique is controllable, cost-effective, and highly efficient since it is conducted at room temperature in an ambient environment. The pressure sensor offers a broad pressure sensing range (7 Pa-50 kPa), a sensitivity of ∼ -0.101 ± 0.005 kPa -1 (<1 kPa), a fast response/relaxation speed of ∼10 ms, a small dependence on temperature variation, and a good cycling stability (>5000 cycles), which is attributed to the UV/O 3 engineered microstructures that amplify and transfer external applied forces and rapidly store/release the energy during the PDMS deformation. The sensors developed show the capability to detect external forces and monitor human health conditions, promising for the potential applications in electronic skin.

Microengineering of artificial capillaries

NASA Astrophysics Data System (ADS)

Moldovan, Nicanor I.

2002-11-01

Biocompatibility and functionality of implanted inorganic medical devices is limited by the local reaction of the organism, with a recently recognized contribution of nearby microvasculature. We explored the possibility to microengineer pre-embedded microvascular networks in the surface of inorganic devices. The implants would thus function as carriers of pre-assembled microvessels, ready to expand, and contribute to local angiogenesis. Based on our own studies on the role played by local microtopography in angiogenesis (the tunneling concept), we have shown the feasibility of endothelial cells cultivation in grooves created on the surface of the materials to be implanted, either polymeric or silicon. In order to develop this new technology, we devised an in situ approach to the study of the cellular behavior on micropatterned surfaces, by use of Laser Scanning Cytometry (LSC). In this report I will present our results regarding the LSC analysis of endothelial cells cultivated in grooves made on the surface of silicon wafers, and the consequences of this treatment on endothelial physiology. When comparing the growth of endothelial cells on line patterned and non-patterned areas, in terms of several morphological parameters of cell nuclei, our data support the conclusion that lateral confinement of endothelial cells induces a quiescent state, possibly by inhibiting their ability to proliferate.

A wearable pressure sensor based on ultra-violet/ozone microstructured carbon nanotube/polydimethylsiloxane arrays for electronic skins

NASA Astrophysics Data System (ADS)

Yu, Guohui; Hu, Jingdong; Tan, Jianping; Gao, Yang; Lu, Yongfeng; Xuan, Fuzhen

2018-03-01

Pressure sensors with high performance (e.g., a broad pressure sensing range, high sensitivities, rapid response/relaxation speeds, temperature-stable sensing), as well as a cost-effective and highly efficient fabrication method are highly desired for electronic skins. In this research, a high-performance pressure sensor based on microstructured carbon nanotube/polydimethylsiloxane arrays was fabricated using an ultra-violet/ozone (UV/O3) microengineering technique. The UV/O3 microengineering technique is controllable, cost-effective, and highly efficient since it is conducted at room temperature in an ambient environment. The pressure sensor offers a broad pressure sensing range (7 Pa-50 kPa), a sensitivity of ˜ -0.101 ± 0.005 kPa-1 (<1 kPa), a fast response/relaxation speed of ˜10 ms, a small dependence on temperature variation, and a good cycling stability (>5000 cycles), which is attributed to the UV/O3 engineered microstructures that amplify and transfer external applied forces and rapidly store/release the energy during the PDMS deformation. The sensors developed show the capability to detect external forces and monitor human health conditions, promising for the potential applications in electronic skin.

The preparation of uranium-adsorbed silica particles as a reference material for the fission track analysis

NASA Astrophysics Data System (ADS)

Park, Y. J.; Lee, M. H.; Pyo, H. Y.; Kim, H. A.; Sohn, S. C.; Jee, K. Y.; Kim, W. H.

2005-06-01

Uranium-adsorbed silica particles were prepared as a reference material for the fission track analysis (FTA) of swipe samples. A modified instrumental setup for particle generation, based on a commercial vibrating orifice aerosol generator to produce various sizes of droplets from a SiO 2 solution, is described. The droplets were transferred into a weak acidic solution bath to produce spherical solid silica particles. The classification of the silica particles in the range from 5 to 20 μm was carried out by the gravitational sedimentation method. The size distribution and morphology of the classified silica particles were investigated by scanning electron microscopy. The physicochemical properties of the classified silica particles such as the surface area, pore size and pore volume were measured. After an adsorption of 5% 235U on the silica particles in a solution adjusted to pH 4.5, the uranium-adsorbed silica particles were calcined up to 950 °C in a furnace to fix the uranium strongly onto the silica particles. The various sizes of uranium-adsorbed silica particles were applied to the FTA for use as a reference material.

Utilization of Waste Biomass (Kitchen Waste) Hydrolysis Residue as Adsorbent for Dye Removal: Kinetic, Equilibrium, and Thermodynamic Studies.

PubMed

Li, Panyu; Chen, Xi; Zeng, Xiaotong; Zeng, Yu; Xie, Yi; Li, Xiang; Wang, Yabo; Xie, Tonghui; Zhang, Yongkui

2018-02-02

Kitchen waste hydrolysis residue (KWHR), which is produced in the bioproduction process from kitchen waste (KW), is usually wasted with potential threats to the environment. Herein, experiments were carried out to evaluate the potential of KWHR as adsorbent for dye (methylene blue, MB) removal from aqueous solution. The adsorbent was characterized using FT-IR and SEM. Adsorption results showed that the operating variables had great effects on the removal efficiency of MB. Kinetic study indicated pseudo-second-order model was suitable to describe the adsorption process. Afterwards, the equilibrium data were well fitted by using Langmuir isotherm model, suggesting a monolayer adsorption. The Langmuir monolayer adsorption capacity was calculated to be 110.13 mg/g, a level comparable to some other low-cost adsorbents. It was found that the adsorption process of MB onto KWHR was spontaneous and exothermic through the estimation of thermodynamic parameters. Thus, KWHR was of great potential to be an alternative adsorbent material to improve the utilization efficiency of bioresource (KW) and lower the cost of adsorbent for color treatment.

Energetics of Elementary Steps in Catalysis and Their Use to Search for New Catalysts

NASA Astrophysics Data System (ADS)

Wolcott, Christopher A.

We live in a society based upon the mass production of chemicals. Whether it is the fuel in a car, the fertilizers used to make food, or the plastics present in just about everything, these chemicals are so ubiquitous that it is difficult to imagine living in a world without them. Nearly all consumer chemicals are produced through a catalytic process, the vast majority of which are heterogeneous. On top of their current, massive presence, heterogeneous catalysts are also expected to play an important role in new emerging technologies such as fuel cells, hydrogen production, green chemistry, and more. Considering their ubiquity in the present and their potential uses in the future, it is no surprise that improving catalyst performance is a very active area of research. Yet despite their ubiquity, and despite their long history of active study, there remains much which is unknown about the fundamentals of catalysts on surfaces. One of the major gaps is in quantitative understanding of the energetics of elementary steps in catalytic reactions on surfaces. The stability or instability of molecules and molecular fragments adsorbed on surfaces in these elementary steps is KEY to understanding what makes one material an effective catalyst and another less effective. In general, one must use single-crystal model catalysts to produce well-defined adsorbates. Classic studies of the energetics of adsorbates on such surfaces have typically involved techniques (such as temperature programmed desorption or equilibrium adsorption experiments) which limit the types of systems which can be studied to those where adsorption is reversible. For most catalytic intermediates present in these elementary steps, this is not the case. Upon adsorption and heating many molecules fall apart and produce strongly bound adsorbates which further dissociate at higher temperatures, or will not leave the surface until they have reacted with something else. Single crystal adsorption calorimetry (SCAC) is a fairly new technique which allows one to probe the heats of formation of such adsorbates for the first time. In this thesis SCAC is used to study the dissociative adsorption of diiodomethane on Pt(111) to produce adsorbed -CH2 and -CH, and water on Fe 3O4(111) and NiO(111) to produce adsorbed -OH. This work expands the library of adsorbates on transition metal surfaces which has been studied by SCAC, and is among the first ever measurements of molecules on well-defined oxide surfaces using SCAC. These results are compared to density functional theory (DFT) calculations of adsorbate energetics, and their use as computational benchmarks is discussed. A new, universally-applicable method of data analysis for SCAC is also developed which allows for the extraction of heat data even in the presence of complex surface reaction/diffusion dynamics without any need for kinetic modeling as required in previous analysis methods, thus greatly expanding the versatility of SCAC. Finally a new method of computational catalyst screening is presented which uses the concept of degree of rate control to simplify calculations compared to the standard method developed by Jens Norskov's group. It greatly reduces the number of adsorbate energies needed to predict the reaction rate for a new catalyst, and provides greater accuracy when studying materials with similar properties to the reference catalyst used. The Norskov method is more robust when extended to materials that are dissimilar. The new method presented here is thus expected to be an important complimentary tool to Norskov's method for high-throughput computational screening. Taken together, the results presented in this dissertation show the importance of experimental measurements for guiding the development of fast quantum mechanical methods like DFT to more closely approach thru "chemical accuracy" in energetic prediction, and how one could use "chemically accurate" DFT energies to rapidly screen potential catalysts for computational catalyst discovery to advance energy and environmental technologies.

Carbide derived carbon from MAX-phases and their separation applications

NASA Astrophysics Data System (ADS)

Hoffman, Elizabeth N.

Improved sorbents with increased selectivity and permeability are needed to meet growing energy and environmental needs. New forms of carbon based sorbents have been discovered recently, including carbons produced by etching metals from metal carbides, known as carbide derived carbons (CDCs). A common method for the synthesis of CDC is by chlorination at elevated temperatures. The goal of this work is to synthesize CDC from ternary carbides and to explore the links between the initial carbide chemistry and structure with the resulting CDCs properties, including porosity. CDC was produced from MAX-phase carbides, in particular Ti3SiC 2, Ti3AlC2, Ti2AlC, and Ta2AlC. Additionally, CDC was produced from Ta-based binary carbides, TaC and Ta 2C, and one carbo-nitride Ti2AlC0.5N0.5. The CDC structure was characterized using XRD, Raman microspectroscopy, and HRTEM. Porosity characterization was performed using sorption analysis with both Ar and N2 as adsorbates. It was determined the microporosity of CDC is related to the density of the initial carbide. The layered structure of the MAX-phase carbides lent toward the formation of larger mesopores within the resulting CDCs, while the amount of mesopores was dependent on the chemistry of the carbide. Furthermore, CDC produced from carbides with extremely high theoretical porosity resulted in small specific surface areas due to a collapse of the carbon structure. To expand the potential applications for CDC beyond powder and bulk forms, CDC membranes were produced from a thin film of TiC deposited by magnetron sputtering onto porous ceramic substrates. The TiC thin film was subsequently chlorinated to produce a bilayer membrane with CDC as the active layer. Both gases and liquids are capable of passing the membrane. The membrane separates based on selective adsorption, rather than a size separation molecular sieving effect. Two applications for CDC produced from MAX-phases were investigated: protein adsorption and gas separation. Sorbents capable of adsorbing large protein molecules efficiently are desirable for many medical applications, including the treatment of sepsis. Primarily mesoporous Ti2AlC-CDC and Ti3AlC2-CDC were proven to adsorb a significant amount of proteins compared to two current carbon adsorbents. When tested for gas separation, CDC was capable of selectively adsorbing gases including SF6, CO2, CH4, and H2. However, the gases were not separated based on their size, but rather on their interaction with the CDC surface.

Facile and scalable synthesis of magnetite/carbon adsorbents by recycling discarded fruit peels and their potential usage in water treatment.

PubMed

Ma, Ji; Sun, Shuangshuang; Chen, Kezheng

2017-06-01

In this study, apple, banana and orange peels were used as precursor compounds for the mass production of magnetite/carbon adsorbents. A so-called "soak-calcination" procedure was employed by firstly soaking these waste fruit peels in FeCl 3 aqueous solutions and secondly calcining these precursors in the nitrogen atmosphere to yield final magnetite/carbon composites. This approach is quite simple and effective to synthesize carbon-based adsorbents on an industrial scale. The as-produced adsorbents feature the merits of appropriate ferromagnetism (>4emug -1 ), high adsorption capacity (several hundreds of milligrams per gram for adsorption of methyl blue, Congo red, rhodamine B and Cr 6+ ions), and good regenerability (>85%). Copyright © 2017 Elsevier Ltd. All rights reserved.

AFM study of adsorption of protein A on a poly(dimethylsiloxane) surface

NASA Astrophysics Data System (ADS)

Yu, Ling; Lu, Zhisong; Gan, Ye; Liu, Yingshuai; Li, Chang Ming

2009-07-01

In this paper, the morphology and kinetics of adsorption of protein A on a PDMS surface is studied by AFM. The results of effects of pH, protein concentration and contact time of the adsorption reveal that the morphology of adsorbed protein A is significantly affected by pH and adsorbed surface concentration, in which the pH away from the isoelectric point (IEP) of protein A could produce electrical repulsion to change the protein conformation, while the high adsorbed surface protein volume results in molecular networks. Protein A can form an adsorbed protein film on PDMS with a maximum volume of 2.45 × 10-3 µm3. This work enhances our fundamental understanding of protein A adsorption on PDMS, a frequently used substrate component in miniaturized immunoassay devices.

EDITORIAL: 15th European Workshop on Micromechanics (MME)

NASA Astrophysics Data System (ADS)

Puers, Bob

2005-07-01

This special issue of Journal of Micromechanics and Microengineering is entirely devoted to the fifteenth European Workshop on Micromechanics (MME), which was held in Leuven, at the Faculty Club, 5-7 September 2004. In this issue you will find a selection of papers presented at this workshop. The MME Workshop is organized every year to gather mostly European scientists and people from industry to discuss topics related to micromachining and microengineering in an informal manner. The first workshop was held at Twente University, the Netherlands, in 1989. The success of that event inaugurated a series of workshops traveling all over Europe. Looking back on the fifteen years of micromachining it is evident that the field has become more mature. More application driven research is now replacing the basic pure technology driven research we once got so excited about. Yet, half of the contributions still cover problems related to fabrication, production and reliability. Traditionally, the workshop aims to bring together young scientists in the field, with emphasis on discussions and communications in a friendly and informal atmosphere. The goal is to stimulate and to improve knowledge in the field, as well as to promote friendships between researchers. This edition of the workshop was no different. More than 70 papers were contributed, and it was decided to widen the scope with contributions also covering non-silicon technologies. This trend had already been informally introduced some years ago. After the third edition, it was decided to open up a selection of the contributed papers to a broader public by publishing them in a special issue of Journal of Micromechanics and Microengineering, and this has continued to the present day. Since the purpose of the workshop clearly is to stimulate younger scientists to enter the field, even immature research is presented there. The selection in this issue, however, aims to bring to you the more advanced level research work. Even so, without doubt, such a selection was not an easy task to perform. A careful choice was made by the Programme Committee of the MME Workshop at first, followed by the regular reviewing procedure at the heart of IOP Publishing. I am proud to be able to present to you this collection of 23 papers. We decided also to include papers dealing with non-lithography based manufacturing techniques in this special issue, in an attempt to widen the scope. With this special issue we hope to give you a good overview of the topics dealt with in this workshop. It goes without saying that all the above was not possible without the individual contributions of all the authors. I owe them much gratitude. Gathered here are contributions of an excellent scientific quality, reflecting a clear up-to-date image of what is going on in Europe in this field. I also wish to extend my thanks to the editorial staff of Journal of Micromechanics and Microengineering. Collaboration with them turns work into pleasure. I wish you a pleasant reading.

Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst.

PubMed

Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz

2012-11-30

Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents. Copyright © 2012 Elsevier Ltd. All rights reserved.

Low Friction Droplet Transportation on a Substrate with a Selective Leidenfrost Effect.

PubMed

Dodd, Linzi E; Wood, David; Geraldi, Nicasio R; Wells, Gary G; McHale, Glen; Xu, Ben B; Stuart-Cole, Simone; Martin, James; Newton, Michael I

2016-08-31

An energy saving Leidenfrost levitation method is introduced to transport microdroplets with virtually frictionless contact between the liquid and solid substrate. Through microengineering of the heating units, selective areas of the whole substrate can be electrothermally activated. A droplet can be levitated as a result of the Leidenfrost effect and further transported when the substrate is tilted slightly. Selective electroheating produces a uniform temperature distribution on the heating units within 1 s in response to a triggering voltage. Alongside these experimental observations, finite element simulations were conducted to understand the role of substrate thermal conductivity on the temperature profile of the selectively heated substrate. We also generated phase diagrams to verify the Leidenfrost regime for different substrate materials. Finally, we demonstrated the possibility of controlling low friction high speed droplet transportation (∼65 mm/s) when the substrate is tilted (∼7°) by structurally designing the substrate. This work establishes the basis for an entirely new approach to droplet microfluidics.

Practical, microfabrication-free device for single-cell isolation.

PubMed

Lin, Liang-I; Chao, Shih-Hui; Meldrum, Deirdre R

2009-08-21

Microfabricated devices have great potential in cell-level studies, but are not easily accessible for the broad biology community. This paper introduces the Microscale Oil-Covered Cell Array (MOCCA) as a low-cost device for high throughput single-cell analysis that can be easily produced by researchers without microengineering knowledge. Instead of using microfabricated structures to capture cells, MOCCA isolates cells in discrete aqueous droplets that are separated by oil on patterned hydrophilic areas across a relatively more hydrophobic substrate. The number of randomly seeded Escherichia coli bacteria in each discrete droplet approaches single-cell levels. The cell distribution on MOCCA is well-fit with Poisson distribution. In this pioneer study, we created an array of 900-picoliter droplets. The total time needed to seed cells in approximately 3000 droplets was less than 10 minutes. Compared to traditional microfabrication techniques, MOCCA dramatically lowers the cost of microscale cell arrays, yet enhances the fabrication and operational efficiency for single-cell analysis.

Novel silicon microchannels device for use in red blood cell deformability studies

NASA Astrophysics Data System (ADS)

Zheng, Xiao-Lin; Liao, Yan-Jian; Zhang, Wen-Xian

2001-10-01

Currently, a number of techniques are used to access cell deformability. We study a novel silicon microchannels device for use in red blood cell deformability. The channels are produced in silicon substrate using microengineering technology. The microgrooves formed in the surface of a single-crystal silicon substrate. They were converted to channels by tightly covering them with an optical flat glass plate. An array of flow channels (number 950 in parallel) have typical dimensions of 5 micrometers width X 5.5 Xm depth, and 30 micrometers length. There the RBC's are forced to pass through channels. Thus, the microchannels are used to simulate human blood capillaries. It provides a specific measurement of individual cell in terms of both flow velocity profile and an index of cell volume while the cell flow through the channels. It dominates the complex cellular flow behavior, such as, the viscosity of whole blood is a nonlinear function of shear rate, index of filtration, etc.

3D Bioprinting for Tissue and Organ Fabrication

PubMed Central

Zhang, Yu Shrike; Yang, Jingzhou; Jia, Weitao; Dell’Erba, Valeria; Assawes, Pribpandao; Shin, Su Ryon; Dokmeci, Mehmet Remzi; Oklu, Rahmi; Khademhosseini, Ali

2016-01-01

The field of regenerative medicine has progressed tremendously over the past few decades in its ability to fabricate functional tissue substitutes. Conventional approaches based on scaffolding and microengineering are limited in their capacity of producing tissue constructs with precise biomimetic properties. Three-dimensional (3D) bioprinting technology, on the other hand, promises to bridge the divergence between artificially engineered tissue constructs and native tissues. In a sense, 3D bioprinting offers unprecedented versatility to co-deliver cells and biomaterials with precise control over their compositions, spatial distributions, and architectural accuracy, therefore achieving detailed or even personalized recapitulation of the fine shape, structure, and architecture of target tissues and organs. Here we briefly describe recent progresses of 3D bioprinting technology and associated bioinks suitable for the printing process. We then focus on the applications of this technology in fabrication of biomimetic constructs of several representative tissues and organs, including blood vessel, heart, liver, and cartilage. We finally conclude with future challenges in 3D bioprinting as well as potential solutions for further development. PMID:27126775

3D Bioprinting for Tissue and Organ Fabrication.

PubMed

Zhang, Yu Shrike; Yue, Kan; Aleman, Julio; Moghaddam, Kamyar Mollazadeh; Bakht, Syeda Mahwish; Yang, Jingzhou; Jia, Weitao; Dell'Erba, Valeria; Assawes, Pribpandao; Shin, Su Ryon; Dokmeci, Mehmet Remzi; Oklu, Rahmi; Khademhosseini, Ali

2017-01-01

The field of regenerative medicine has progressed tremendously over the past few decades in its ability to fabricate functional tissue substitutes. Conventional approaches based on scaffolding and microengineering are limited in their capacity of producing tissue constructs with precise biomimetic properties. Three-dimensional (3D) bioprinting technology, on the other hand, promises to bridge the divergence between artificially engineered tissue constructs and native tissues. In a sense, 3D bioprinting offers unprecedented versatility to co-deliver cells and biomaterials with precise control over their compositions, spatial distributions, and architectural accuracy, therefore achieving detailed or even personalized recapitulation of the fine shape, structure, and architecture of target tissues and organs. Here we briefly describe recent progresses of 3D bioprinting technology and associated bioinks suitable for the printing process. We then focus on the applications of this technology in fabrication of biomimetic constructs of several representative tissues and organs, including blood vessel, heart, liver, and cartilage. We finally conclude with future challenges in 3D bioprinting as well as potential solutions for further development.

Methane Recovery from Gaseous Mixtures Using Carbonaceous Adsorbents

NASA Astrophysics Data System (ADS)

Buczek, Bronisław

2016-06-01

Methane recovery from gaseous mixtures has both economical and ecological aspect. Methane from different waste gases like mine gases, nitrogenated natural gases and biogases can be treated as local source for production electric and heat energy. Also occurs the problem of atmosphere pollution with methane that shows over 20 times more harmful environmental effect in comparison to carbon dioxide. One of the ways utilisation such gases is enrichment of methane in the PSA technique, which requires appropriate adsorbents. Active carbons and carbon molecular sieve produced by industry and obtained in laboratory scale were examined as adsorbent for methane recuperation. Porous structure of adsorbents was investigated using densimetry measurements and adsorption of argon at 77.5K. On the basis of adsorption data, the Dubinin-Radushkevich equation parameters, micropore volume (Wo) and characteristics of energy adsorption (Eo) as well as area micropores (Smi) and BET area (SBET) were determined. The usability of adsorbents in enrichment of the methane was evaluated in the test, which simulate the basic stages of PSA process: a) adsorbent degassing, b) pressure raise in column by feed gas, c) cocurrent desorption with analysis of out flowing gas. The composition of gas phase was accepted as the criterion of the suitability of adsorbent for methane separation from gaseous mixtures. The relationship between methane recovery from gas mixture and texture parameters of adsorbents was found.

Modeling of fixed-bed column studies for the adsorption of cadmium onto novel polymer-clay composite adsorbent.

PubMed

Unuabonah, Emmanuel I; Olu-Owolabi, Bamidele I; Fasuyi, Esther I; Adebowale, Kayode O

2010-07-15

Kaolinite clay was treated with polyvinyl alcohol to produce a novel water-stable composite called polymer-clay composite adsorbent. The modified adsorbent was found to have a maximum adsorption capacity of 20,400+/-13 mg/L (1236 mg/g) and a maximum adsorption rate constant of approximately = 7.45x10(-3)+/-0.0002 L/(min mg) at 50% breakthrough. Increase in bed height increased both the breakpoint and exhaustion point of the polymer-clay composite adsorbent. The time for the movement of the Mass Transfer Zone (delta) down the column was found to increase with increasing bed height. The presence of preadsorbed electrolyte and regeneration were found to reduce this time. Increased initial Cd(2+) concentration, presence of preadsorbed electrolyte, and regeneration of polymer-clay composite adsorbent reduced the volume of effluent treated. Premodification of polymer-clay composite adsorbent with Ca- and Na-electrolytes reduced the rate of adsorption of Cd(2+) onto polymer-clay composite and lowered the breakthrough time of the adsorbent. Regeneration and re-adsorption studies on the polymer-clay composite adsorbent presented a decrease in the bed volume treated at both the breakpoint and exhaustion points of the regenerated bed. Experimental data were observed to show stronger fits to the Bed Depth Service Time (BDST) model than the Thomas model. 2010 Elsevier B.V. All rights reserved.

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

NASA Technical Reports Server (NTRS)

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

1994-01-01

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

Near infrared-modulated propulsion of catalytic Janus polymer multilayer capsule motors.

PubMed

Wu, Yingjie; Si, Tieyan; Lin, Xiankun; He, Qiang

2015-01-11

The use of a near-infrared (NIR) laser for reversible modulation of a bubble-driven Janus polymer capsule motor is demonstrated. This process was mediated through illumination of the metal face of the Janus capsule motor at the critical concentration of peroxide fuel. Such an effective control of the propulsion of chemically powered microengines holds a considerable promise for diverse applications.

Mechanical Computing in Microelectromechanical Systems (MEMS)

DTIC Science & Technology

2003-03-01

New York: John Wiley and Sons, Inc., 1968. 25. Helvajian , H . and S. Janson, Microengineering Aerospace Systems, ch. Micro- engineering Space Systems...sacrificial layer. (g)Strip remaining resist. ( h ) Deposit a structural layer(conformal deposition is shown). (i) Deposit resist. (j) Expose resist...layer is then deposited, and assuming a conformal process, the structural layer will follow the topography of the sacrificial layer (Figure 2.9( h

EDITORIAL: The 19th MicroMechanics Europe Workshop (MME 2008) The 19th MicroMechanics Europe Workshop (MME 2008)

NASA Astrophysics Data System (ADS)

Schnakenberg, Uwe

2009-07-01

This special issue of Journal of Micromechanics and Microengineering is devoted to the 19th MicroMechanics Europe Workshop (MME 08), which took place at the RWTH Aachen University, Aachen, Germany, from 28-30 September, 2008. The workshop is a well recognized and established European event in the field of micro system technology using thin-film technologies for creating micro components, micro sensors, micro actuators, and micro systems. The first MME Workshop was held 1989 in Enschede (The Netherlands) and continued 1990 in Berlin (Germany), 1992 in Leuven (Belgium), and then was held annually in Neuchâtel (Switzerland), Pisa (Italy), Copenhagen (Denmark), Barcelona (Spain), Southampton (UK), Ulvik in Hardanger (Norway), Gif-sur-Yvette (France), Uppsala (Sweden), Cork (Ireland), Sinaia (Romania), Delft (The Netherlands), Leuven (Belgium), Göteborg (Sweden), Southampton (UK), and in Guimarães (Portugal). The two day workshop was attended by 180 delegates from 26 countries all over Europe and from Armenia, Austria, Bulgaria, Canada, China, Cuba, Iran, Japan, Korea, Malaysia, Taiwan, Turkey, and the United States of America. A total of 97 papers were accepted for presentation and there were a further five keynote presentations. I am proud to present 22 high-quality papers from MME 2008 selected for their novelty and relevance to Journal of Micromechanics and Microengineering. All the papers went through the regular reviewing procedure of IOP Publishing. I am eternally grateful to all the referees for their excellent work. I would also like to extend my thanks to the members of the Programme Committee of MME 2008, Dr Reinoud Wolffenbuttel, Professor José Higino Correia, and Dr Patrick Pons for pre-selection of the papers as well as to Professor Robert Puers for advice on the final selection of papers. My thanks also go to Dr Ian Forbes of IOP Publishing for managing the entire process and to the editorial staff of Journal of Micromechanics and Microengineering. I trust that this special issue will provide new trends of the emerging field of micro system technology and I hope you enjoy reading it.

In situ modification of chromatography adsorbents using cold atmospheric pressure plasmas

NASA Astrophysics Data System (ADS)

Olszewski, P.; Willett, T. C.; Theodosiou, E.; Thomas, O. R. T.; Walsh, J. L.

2013-05-01

Efficient manufacturing of increasingly sophisticated biopharmaceuticals requires the development of new breeds of chromatographic materials featuring two or more layers, with each layer affording different functions. This letter reports the in situ modification of a commercial beaded anion exchange adsorbent using atmospheric pressure plasma generated within gas bubbles. The results show that exposure to He-O2 plasma in this way yields significant reductions in the surface binding of plasmid DNA to the adsorbent exterior, with minimal loss of core protein binding capacity; thus, a bi-layered chromatography material exhibiting both size excluding and anion exchange functionalities within the same bead is produced.

(Non) formation of methanol by direct hydrogenation of formate on copper catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yong; Mims, Charles A.; Disselkamp, Robert S.

2010-10-14

We have attempted to hydrogenate adsorbed formate species on copper catalysts to probe the importance of this postulated mechanistic step in methanol synthesis. Surface formate coverages up to 0.25 were produced at temperatures between 413K and 453K on supported (Cu/SiO2) copper and unsupported copper catalysts. The adlayers were produced by various methods including (1) steady state catalytic conditions in CO2-H2 (3:1, 6 bar) atmospheres, and (2) by exposure of the catalysts to formic acid. As reported in earlier work, the catalytic surface at steady state contains bidentate formate species with coverages up to saturation levels of ~ 0.25 at themore » low temperatures of this study. The reactivity of these formate adlayers was investigated at relevant reaction temperatures in atmospheres containing up to 6 bar H2 partial pressure by simultaneous mass spectrometry (MS) and infrared (IR) spectroscopy measurements. The yield of methanol during the attempted hydrogenation (“titration”) of these adlayers was insignificant (<0.2 mol % of the formate adlayer) even in dry hydrogen partial pressures up to 6 bar. Hydrogen titration of formate species produced from formic acid also failed to produce significant quantities of methanol, and attempted titration in gases consisting of CO-hydrogen mixtures or dry CO2 were also unproductive. The formate decomposition kinetics, measured by IR, were also unaffected by these changes in the gas composition. Similar experiments on unsupported copper also failed to show any methanol. From these results, we conclude that methanol synthesis on copper cannot result from the direct hydrogenation of (bidentate) formate species in simple steps involving adsorbed H species alone. Furthermore, experiments performed on both supported (Cu/SiO2) and unsupported copper catalysts gave similar results implying that the methanol synthesis reaction mechanism only involves metal surface chemistry. Pre-exposure of the bidentate formate adlayer to oxidation by O2 or N2O produces a change to a monodentate configuration. Attempted titration of this monodentate formate/O coadsorbed layer in dry hydrogen produces significant quantities of methanol, although decomposition of formate to carbon dioxide and hydrogen remains the dominant reaction pathway. Simultaneous production of water is also observed during this titration as the copper surface is re-reduced. These results indicate that co-adsorbates related to surface oxygen or water-derived species may be critical to methanol production on copper, perhaps assisting in the hydrogenation of adsorbed formate to adsorbed methoxyl.« less

Methodology of citrate-based biomaterial development and application

NASA Astrophysics Data System (ADS)

Tran, M. Richard

Biomaterials play central roles in modern strategies of regenerative medicine and tissue engineering. Attempts to find tissue-engineered solutions to cure various injuries or diseases have led to an enormous increase in the number of polymeric biomaterials over the past decade. The breadth of new materials arises from the multiplicity of anatomical locations, cell types, and mode of application, which all place application-specific requirements on the biomaterial. Unfortunately, many of the currently available biodegradable polymers are limited in their versatility to meet the wide range of requirements for tissue engineering. Therefore, a methodology of biomaterial development, which is able to address a broad spectrum of requirements, would be beneficial to the biomaterial field. This work presents a methodology of citrate-based biomaterial design and application to meet the multifaceted needs of tissue engineering. We hypothesize that (1) citric acid, a non-toxic metabolic product of the body (Krebs Cycle), can be exploited as a universal multifunctional monomer and reacted with various diols to produce a new class of soft biodegradable elastomers with the flexibility to tune the material properties of the resulting material to meet a wide range of requirements; (2) the newly developed citrate-based polymers can be used as platform biomaterials for the design of novel tissue engineering scaffolding; and (3) microengineering approaches in the form thin scaffold sheets, microchannels, and a new porogen design can be used to generate complex cell-cell and cell-microenvironment interactions to mimic tissue complexity and architecture. To test these hypotheses, we first developed a methodology of citrate-based biomaterial development through the synthesis and characterization of a family of in situ crosslinkable and urethane-doped elastomers, which are synthesized using simple, cost-effective strategies and offer a variety methods to tailor the material properties to meet the needs of a particular application. Next, we introduced a new porogen generation technique, and showed the potential application of the newly developed materials through the fabrication and characterization of scaffold sheets, multiphasic small diameter vascular grafts, and multichanneled nerve guides. Finally, the in vivo applications of citrate-based materials are exemplified through the evaluation of peripheral nerve regeneration using multichanneled guides and the ability to assist in injection-based endoscopic mucosal resection therapy. The results presented in this work show that citric acid can be utilized as a cornerstone in the development of novel biodegradable materials, and combined with microengineering approaches to produce the next generation of tissue engineering scaffolding. These enabling new biomaterials and scaffolding strategies should address many of the existing challenges in tissue engineering and advance the field as a whole.

Biochar characteristics produced from rice husks and their sorption properties for the acetanilide herbicide metolachlor.

PubMed

Wei, Lan; Huang, Yufen; Li, Yanliang; Huang, Lianxi; Mar, Nyo Nyo; Huang, Qing; Liu, Zhongzhen

2017-02-01

Rice husk biochar (RHBC) was prepared for use as adsorbents for the herbicide metolachlor. The characteristics and sorption properties of metolachlor adsorbed by the RHBC prepared at different pyrolysis temperatures were determined by analysis of physico-chemical characteristics, Fourier transform infrared spectroscopy (FTIR), Boehm titration, scanning electron microscopy (SEM), and thermodynamics and kinetics adsorption. With increasing pyrolysis temperature, the RHBC surface area greatly increased (from 2.57 to 53.08 m 2  g -1 ). RHBC produced at the highest temperature (750 °C) had the greatest surface area; SEM also showed the formation of a porous surface on RH-750 biochar. The sorption capacity of RHBC also increased significantly with increasing pyrolysis temperature and was characterized by the Freundlich constant K f for the adsorption capacity increasing from 125.17-269.46 (pyrolysis at 300 °C) to 339.94-765.24 (pyrolysis at 750 °C). The results indicated that the surface area and pore diameter of RHBC produced with high pyrolysis temperature (i.e., 750 °C) had the greatest impact on the adsorption of metolachlor. The FTIR, Boehm titration, and SEM analysis showed that the greatest number of surface groups were on RHBC produced at the lowest temperature (300 °C). The biochars produced at different pyrolysis temperatures had different mechanisms of adsorbing metolachlor, which exhibited a transition from hydrogen bonds dominant at low pyrolytic temperature to pore-filling dominant at higher pyrolytic temperature.

Adsorption of 1-naphthyl methyl carbamate in water by utilizing a surface molecularly imprinted polymer

NASA Astrophysics Data System (ADS)

So, Juhyok; Pang, Cholho; Dong, Hongxing; Jang, Paeksan; U, Juhyok; Ri, Kumchol; Yun, Cholyong

2018-05-01

Surface molecularly imprinting polymer (SMIP) was utilized in the removal of a residual pesticide (carbaryl (CBL)) in water and simulated fruit juice. Being the crosslinking agent, ethylene glycol dimethacrylate (EGDMA) was copolymerized with the monomer, methacrylic acid (MAA) and CBL as the template molecules on the surface of the silica gel particles to produce the SMIP adsorbents. The SMIP adsorbents showed good selectivity and good adsorption capacity for CBL in the competitive adsorptions with two structurally related carbamate pesticides. The effect of the pretreatment solvents on the adsorption capacity of the SMIP adsorbent was investigated with the results of the numerical simulations. The adsorption isotherms and the adsorption kinetics were well described by the Freundlich equilibrium model and the pseudo-second-order kinetic model, respectively. Scatchard plot analysis revealed that there were two classes of binding sites populated in the SMIP adsorbents. In addition, the good selective adsorption of CBL by the SMIP adsorbent in a simulated fruit juice containing vitamin C and fructose indicated the great potential of the SMIP adsorbents to remove residual pesticide in food industry and processing industry for agricultural products.

Capture and 3D culture of colonic crypts and colonoids in a microarray platform.

PubMed

Wang, Yuli; Ahmad, Asad A; Shah, Pavak K; Sims, Christopher E; Magness, Scott T; Allbritton, Nancy L

2013-12-07

Crypts are the basic structural and functional units of colonic epithelium and can be isolated from the colon and cultured in vitro into multi-cell spheroids termed "colonoids". Both crypts and colonoids are ideal building blocks for construction of an in vitro tissue model of the colon. Here we proposed and tested a microengineered platform for capture and in vitro 3D culture of colonic crypts and colonoids. An integrated platform was fabricated from polydimethylsiloxane which contained two fluidic layers separated by an array of cylindrical microwells (150 μm diameter, 150 μm depth) with perforated bottoms (30 μm opening, 10 μm depth) termed "microstrainers". As fluid moved through the array, crypts or colonoids were retained in the microstrainers with a >90% array-filling efficiency. Matrigel as an extracellular matrix was then applied to the microstrainers to generate isolated Matrigel pockets encapsulating the crypts or colonoids. After supplying the essential growth factors, epidermal growth factor, Wnt-3A, R-spondin 2 and noggin, 63 ± 13% of the crypts and 77 ± 8% of the colonoids cultured in the microstrainers over a 48-72 h period formed viable 3D colonoids. Thus colonoid growth on the array was similar to that under standard culture conditions (78 ± 5%). Additionally the colonoids displayed the same morphology and similar numbers of stem and progenitor cells as those under standard culture conditions. Immunofluorescence staining confirmed that the differentiated cell-types of the colon, goblet cells, enteroendocrine cells and absorptive enterocytes, formed on the array. To demonstrating the utility of the array in tracking the colonoid fate, quantitative fluorescence analysis was performed on the arrayed colonoids exposed to reagents such as Wnt-3A and the γ-secretase inhibitor LY-411575. The successful formation of viable, multi-cell type colonic tissue on the microengineered platform represents a first step in the building of a "colon-on-a-chip" with the goal of producing the physiologic structure and organ-level function of the colon for controlled experiments.

Placenta-on-a-chip: a novel platform to study the biology of the human placenta.

PubMed

Lee, Ji Soo; Romero, Roberto; Han, Yu Mi; Kim, Hee Chan; Kim, Chong Jai; Hong, Joon-Seok; Huh, Dongeun

2016-01-01

Studying the biology of the human placenta represents a major experimental challenge. Although conventional cell culture techniques have been used to study different types of placenta-derived cells, current in vitro models have limitations in recapitulating organ-specific structure and key physiological functions of the placenta. Here we demonstrate that it is possible to leverage microfluidic and microfabrication technologies to develop a microengineered biomimetic model that replicates the architecture and function of the placenta. A "Placenta-on-a-Chip" microdevice was created by using a set of soft elastomer-based microfabrication techniques known as soft lithography. This microsystem consisted of two polydimethylsiloxane (PDMS) microfluidic channels separated by a thin extracellular matrix (ECM) membrane. To reproduce the placental barrier in this model, human trophoblasts (JEG-3) and human umbilical vein endothelial cells (HUVECs) were seeded onto the opposite sides of the ECM membrane and cultured under dynamic flow conditions to form confluent epithelial and endothelial layers in close apposition. We tested the physiological function of the microengineered placental barrier by measuring glucose transport across the trophoblast-endothelial interface over time. The permeability of the barrier study was analyzed and compared to that obtained from acellular devices and additional control groups that contained epithelial or endothelial layers alone. Our microfluidic cell culture system provided a tightly controlled fluidic environment conducive to the proliferation and maintenance of JEG-3 trophoblasts and HUVECs on the ECM scaffold. Prolonged culture in this model produced confluent cellular monolayers on the intervening membrane that together formed the placental barrier. This in vivo-like microarchitecture was also critical for creating a physiologically relevant effective barrier to glucose transport. Quantitative investigation of barrier function was conducted by calculating permeability coefficients and metabolic rates in varying conditions of barrier structure. The rates of glucose transport and metabolism were consistent with previously reported in vivo observations. The "Placenta-on-a-Chip" microdevice described herein provides new opportunities to simulate and analyze critical physiological responses of the placental barrier. This system may be used to address the major limitations of existing placenta model systems and serve to enable research platforms for reproductive biology and medicine.

Energy balance for uranium recovery from seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schneider, E.; Lindner, H.

The energy return on investment (EROI) of an energy resource is the ratio of the energy it ultimately produces to the energy used to recover it. EROI is a key viability measure for a new recovery technology, particularly in its early stages of development when financial cost assessment would be premature or highly uncertain. This paper estimates the EROI of uranium recovery from seawater via a braid adsorbent technology. In this paper, the energy cost of obtaining uranium from seawater is assessed by breaking the production chain into three processes: adsorbent production, adsorbent deployment and mooring, and uranium elution andmore » purification. Both direct and embodied energy inputs are considered. Direct energy is the energy used by the processes themselves, while embodied energy is used to fabricate their material, equipment or chemical inputs. If the uranium is used in a once-through fuel cycle, the braid adsorbent technology EROI ranges from 12 to 27, depending on still-uncertain performance and system design parameters. It is highly sensitive to the adsorbent capacity in grams of U captured per kg of adsorbent as well as to potential economies in chemical use. This compares to an EROI of ca. 300 for contemporary terrestrial mining. It is important to note that these figures only consider the mineral extraction step in the fuel cycle. At a reference performance level of 2.76 g U recovered per kg adsorbent immersed, the largest energy consumers are the chemicals used in adsorbent production (63%), anchor chain mooring system fabrication and operations (17%), and unit processes in the adsorbent production step (12%). (authors)« less

Photochemical synthesis of simple organic free radicals on simulated planetary surfaces - An ESR study

NASA Technical Reports Server (NTRS)

Tseng, S.-S.; Chang, S.

1975-01-01

Electron spin resonance (ESR) spectroscopy provided evidence for formation of hydroxyl radicals during ultraviolet photolysis (254 nm) at -170 C of H2O adsorbed on silica gel or of silica gel alone. The carboxyl radical was observed when CO or CO2 or a mixture of CO and CO2 adsorbed on silica gel at -170 C was irradiated. The ESR signals of these radicals slowly disappeared when the irradiated samples were warmed to room temperature. However, reirradiation of CO or CO2, or the mixture CO and CO2 on silica gel at room temperature then produced a new species, the carbon dioxide anion radical, which slowly decayed and was identical with that produced by direct photolysis of formic acid adsorbed on silica gel. The primary photochemical process may involve formation of hydrogen and hydroxyl radicals. Subsequent reactions of these radicals with adsorbed CO or CO2 or both yield carboxyl radicals, CO2H, the precursors of formic acid. These results confirm the formation of formic acid under simulated Martian conditions and provide a mechanistic basis for gauging the potential importance of gas-solid photochemistry for chemical evolution on other extraterrestrial bodies, on the primitive earth, and on dust grains in the interstellar medium.

A novel adsorbent obtained by inserting carbon nanotubes into cavities of diatomite and applications for organic dye elimination from contaminated water.

PubMed

Yu, Hongwen; Fugetsu, Bunshi

2010-05-15

A novel approach is described for establishing adsorbents for elimination of water-soluble organic dyes by using multi-walled carbon nanotubes (MWCNTs) as the adsorptive sites. Agglomerates of MWCNTs were dispersed into individual tubes (dispersed-MWCNTs) using sodium n-dodecyl itaconate mixed with 3-(N,N-dimethylmyristylammonio)-propanesulfonate as the dispersants. The resultant dispersed-MWCNTs were inserted into cavities of diatomite to form composites of diatomite/MWCNTs. These composites were finally immobilized onto the cell walls of flexible polyurethane foams (PUF) through an in situ PUF formation process to produce the foam-like CNT-based adsorbent. Ethidium bromide, acridine orange, methylene blue, eosin B, and eosin Y were chosen to represent typical water-soluble organic dyes for studying the adsorptive capabilities of the foam-like CNT-based adsorbent. For comparisons, adsorptive experiments were also carried out by using agglomerates of the sole MWCNTs as adsorbents. The foam-like CNT-based adsorbents were found to have higher adsorptive capacities than the CNT agglomerates for all five dyes; in addition, they are macro-sized, durable, flexible, hydrophilic and easy to use. Adsorption isotherms plotted based on the Langmuir equation gave linear results, suggesting that the foam-like CNT-based adsorbent functioned in the Langmuir adsorption manner. The foam-like CNT-based adsorbents are reusable after regeneration with aqueous ethanol solution. Copyright (c) 2009 Elsevier B.V. All rights reserved.

How Small Is Too Small? Technology into 2035

DTIC Science & Technology

2010-12-01

by Arrayed Polyimide Joint Actuators,” Journal of Micromechanics and Microengineering 10, no. 3 [2000]: 337–49.) 6 A more integrated microrobot is...application-specific in- tegrated circuit used for overall control; three piezoelectric legs used for forward, reverse, and z-axis rotation move- ments...a piezoelectric touch sensor; and power storage Figure 3. Captured video image of an integrated and autonomous micro- robot. (Reproduced from Seth

SAM-based Cell Transfer to Photopatterned Hydrogels for Microengineering Vascular-Like Structures

PubMed Central

Sadr, Nasser; Zhu, Mojun; Osaki, Tatsuya; Kakegawa, Takahiro; Yang, Yunzhi; Moretti, Matteo; Fukuda, Junji; Khademhosseini, Ali

2011-01-01

A major challenge in tissue engineering is to reproduce the native 3D microvascular architecture fundamental for in vivo functions. Current approaches still lack a network of perfusable vessels with native 3D structural organization. Here we present a new method combining self-assembled monolayer (SAM)-based cell transfer and gelatin methacrylate hydrogel photopatterning techniques for microengineering vascular structures. Human umbilical vein cell (HUVEC) transfer from oligopeptide SAM-coated surfaces to the hydrogel revealed two SAM desorption mechanisms: photoinduced and electrochemically triggered. The former, occurs concomitantly to hydrogel photocrosslinking, and resulted in efficient (>97%) monolayer transfer. The latter, prompted by additional potential application, preserved cell morphology and maintained high transfer efficiency of VE-cadherin positive monolayers over longer culture periods. This approach was also applied to transfer HUVECs to 3D geometrically defined vascular-like structures in hydrogels, which were then maintained in perfusion culture for 15 days. As a step toward more complex constructs, a cell-laden hydrogel layer was photopatterned around the endothelialized channel to mimic the vascular smooth muscle structure of distal arterioles. This study shows that the coupling of the SAM-based cell transfer and hydrogel photocrosslinking could potentially open up new avenues in engineering more complex, vascularized tissue constructs for regenerative medicine and tissue engineering applications. PMID:21802723

Bridging the gap: from 2D cell culture to 3D microengineered extracellular matrices

PubMed Central

Li, Yanfen

2016-01-01

Historically the culture of mammalian cells in the laboratory has been performed on planar substrates with media cocktails that are optimized to maintain phenotype. However, it is becoming increasingly clear that much of biology discerned from 2D studies does not translate well to the 3D microenvironment. Over the last several decades, 2D and 3D microengineering approaches have been developed that better recapitulate the complex architecture and properties of in vivo tissue. Inspired by the infrastructure of the microelectronics industry, lithographic patterning approaches have taken center stage because of the ease in which cell-sized features can be engineered on surfaces and within a broad range of biocompatible materials. Patterning and templating techniques enable precise control over extracellular matrix properties including: composition, mechanics, geometry, cell-cell contact, and diffusion. In this review article we will explore how the field of engineered extracellular matrices has evolved with the development of new hydrogel chemistry and the maturation of micro- and nano- fabrication. Guided by the spatiotemporal regulation of cell state in developing tissues, we will review the maturation of micropatterning in 2D, pseudo-3D systems, and patterning within 3D hydrogels in the context of translating the information gained from 2D systems to synthetic engineered 3D tissues. PMID:26592366

Selective hydrophilic modification of Parylene C films: a new approach to cell micro-patterning for synthetic biology applications.

PubMed

Trantidou, T; Rao, C; Barrett, H; Camelliti, P; Pinto, K; Yacoub, M H; Athanasiou, T; Toumazou, C; Terracciano, C M; Prodromakis, T

2014-06-01

We demonstrate a simple, accurate and versatile method to manipulate Parylene C, a material widely known for its high biocompatibility, and transform it to a substrate that can effectively control the cellular microenvironment and consequently affect the morphology and function of the cells in vitro. The Parylene C scaffolds are fabricated by selectively increasing the material's surface water affinity through lithography and oxygen plasma treatment, providing free bonds for attachment of hydrophilic biomolecules. The micro-engineered constructs were tested as culture scaffolds for rat ventricular fibroblasts and neonatal myocytes (NRVM), toward modeling the unique anisotropic architecture of native cardiac tissue. The scaffolds induced the patterning of extracellular matrix compounds and therefore of the cells, which demonstrated substantial alignment compared to typical unstructured cultures. Ca(2+) cycling properties of the NRVM measured at rates of stimulation 0.5-2 Hz were significantly modified with a shorter time to peak and time to 90% decay, and a larger fluorescence amplitude (p < 0.001). The proposed technique is compatible with standard cell culturing protocols and exhibits long-term pattern durability. Moreover, it allows the integration of monitoring modalities into the micro-engineered substrates for a comprehensive interrogation of physiological parameters.

Correlation between the sorption of dissolved oxygen onto chitosan and its antimicrobial activity against Esherichia coli.

PubMed

Gylienė, Ona; Servienė, Elena; Vepštaitė, Iglė; Binkienė, Rima; Baranauskas, Mykolas; Lukša, Juliana

2015-10-20

The ability of chitosan to adsorb dissolved oxygen from solution depends on its physical shape and is related to the surface area. Depending on conditions chitosan is capable of adsorbing or releasing oxygen. Chitosan, modificated by the substances possessing antimicrobial activity, such as succinic acid, Pd(II) ions, metallic Pd or Ag, distinctly increases the ability to adsorb the dissolved oxygen. The additional treatment of chitosan with air oxygen or electrochemically produced oxygen also increases the uptake of dissolved oxygen by chitosan. A strong correlation between the amount of oxygen adsorbed onto chitosan and its antimicrobial activity against Esherichia coli has been observed. This finding suggests that one of the sources of antimicrobial activity of chitosan is the ability to sorb dissolved oxygen, along with other well-known factors such as physical state and chemical composition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Properties and potential environmental applications of carbon adsorbents from waste tire rubber

USGS Publications Warehouse

Lehmann, C.M.B.; Rameriz, D.; Rood, M.J.; Rostam-Abadi, M.

2000-01-01

The properties of tire-derived carbon adsorbents (TDCA) produced from select tire chars were compared with those derived from an Illinois coal and pistachio nut shells. Chemical analyses of the TDCA indicated that these materials contain metallic elements not present in coal-and nut shell-derived carbons. These metals, introduced during the production of tire rubber, potentially catalyze steam gasification reactions of tire char. TDCA carbons contained larger meso-and macopore volumes than their counterparts derived from coal and nut shell (on the moisture-and ash-free-basis). Adsorptive properties of the tire-derived adsorbent carbons for air separation, gas storage, and gas clean up were also evaluated and compared with those of the coal-and nut shell derived carbons as well as a commercial activated carbon. The results revealed that TDCA carbons are suitable adsorbents for removing vapor-phase mercury from combustion flue gases and hazardous organic compounds from industrial gas streams.

Applications of Brazilian pine-fruit shell in natural and carbonized forms as adsorbents to removal of methylene blue from aqueous solutions--kinetic and equilibrium study.

PubMed

Royer, Betina; Cardoso, Natali F; Lima, Eder C; Vaghetti, Julio C P; Simon, Nathalia M; Calvete, Tatiana; Veses, Renato Cataluña

2009-05-30

The Brazilian pine-fruit shell (Araucaria angustifolia) is a food residue, which was used in natural and carbonized forms, as low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. Chemical treatment of Brazilian pine-fruit shell (PW), with sulfuric acid produced a non-activated carbonaceous material (C-PW). Both PW and C-PW were tested as low-cost adsorbents for the removal of MB from aqueous effluents. It was observed that C-PW leaded to a remarkable increase in the specific surface area, average porous volume, and average porous diameter of the adsorbent when compared to PW. The effects of shaking time, adsorbent dosage and pH on adsorption capacity were studied. In basic pH region (pH 8.5) the adsorption of MB was favorable. The contact time required to obtain the equilibrium was 6 and 4h at 25 degrees C, using PW and C-PW as adsorbents, respectively. Based on error function values (F(error)) the kinetic data were better fitted to fractionary-order kinetic model when compared to pseudo-first order, pseudo-second order, and chemisorption kinetic models. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. For MB dye the equilibrium data were better fitted to the Sips isotherm model using PW and C-PW as adsorbents.

Selective removal of caffeine from tea extracts using macroporous crosslinked polyvinyl alcohol adsorbents.

PubMed

Ma, Ning; Wang, Peng; Kong, Xia; Shi, Rongfu; Yuan, Zhi; Wang, Chunhong

2012-01-01

The hydrolysis reaction of ester groups in vinyl acetate (VAc) was used to introduce hydroxyl groups into the matrix of a macroporous adsorbent, which was itself prepared by free radical suspension copolymerization of triallyl isocyanurate (TAIC) and VAc. Therefore, the copolymerization incompatibility between the hydrophilic and the hydrophobic monomer was overcome successfully and the hydrophobic matrix of the polymeric adsorbent containing a polyvinyl alcohol (PVA) segment was obtained. Introduction of the PVA segment decreased the hydrophobic adsorption affinity of the adsorbent while producing the hydrogen-bonding interaction. When isolating the two active components, polyphenols (TPh) and caffeine (CAF), from green tea extracts, this polymeric adsorbent, namely poly(TAIC-co-VA), exhibited good adsorption selectivity towards TPh over CAF. The adsorption mechanism leading to this selectivity involved a hydrophobic interaction mechanism for CAF and multiple weak hydrophobic and hydrogen-bonding interactions for TPh. The adsorption thermodynamics for TPh on poly(TAIC-co-VA) were studied. The effects of adsorbent structure and gradient desorption conditions on isolation were investigated. The result showed that adsorbent, with 20% TAIC content, was able to efficiently remove CAF from different tea extracts with different ratios of TPh and CAF. Finally, almost no CAF was detected in the TPh fraction and the recovery of TPh was greater than 95%. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of carbon monoxide-free hydrogen and helium from a high-purity source

DOEpatents

Golden, Timothy Christopher [Allentown, PA; Farris, Thomas Stephen [Bethlehem, PA

2008-11-18

The invention provides vacuum swing adsorption processes that produce an essentially carbon monoxide-free hydrogen or helium gas stream from, respectively, a high-purity (e.g., pipeline grade) hydrogen or helium gas stream using one or two adsorber beds. By using physical adsorbents with high heats of nitrogen adsorption, intermediate heats of carbon monoxide adsorption, and low heats of hydrogen and helium adsorption, and by using vacuum purging and high feed stream pressures (e.g., pressures of as high as around 1,000 bar), pipeline grade hydrogen or helium can purified to produce essentially carbon monoxide -free hydrogen and helium, or carbon monoxide, nitrogen, and methane-free hydrogen and helium.

Aqueous two-phase printing of cell-containing contractile collagen microgels.

PubMed

Moraes, Christopher; Simon, Arlyne B; Putnam, Andrew J; Takayama, Shuichi

2013-12-01

This work describes the use of aqueous two-phase systems to print cell-containing contractile collagen microdroplets. The fully aqueous conditions enable convenient formation of sub-microliter 'microgels' that are much smaller than otherwise possible to fabricate while maintaining high cell viability. The produced microgels contract over several days, mimicking the behavior of macroscale contraction assays, which have been valued as an important biological readout for over three decades. Use of microgels not only reduces reagent consumption and increases throughput of the assay, but also improves transport of molecules into and out of the collagen matrix, thereby enabling efficient and more precise studies of timed stimulation profiles. Utility of the technology is demonstrated by analyzing the effects of TGF-β1 on gel contraction, and we demonstrate that brief 'burst' stimulation profiles in microgels prompt contraction of the matrix, a feature not observed in the conventional macroscale assay. The fully aqueous process also enables the integration of contractile collagen microgels within existing cell culture systems, and we demonstrate proof-of-principle experiments in which a contractile collagen droplet is fabricated in situ on an existing epithelial monolayer. The simplicity, versatility and ability to robustly produce collagen microgels should allow effective translation of this microengineering technology into a variety of research environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dehydration of ethanol by facile synthesized glucose-based silica.

PubMed

Tang, Baokun; Bi, Wentao; Row, Kyung Ho

2013-02-01

Bioethanol is considered a potential liquid fuel that can be produced from biomass by fermentation and distillation. Although most of the water is removed by distillation, the purity of ethanol is limited to 95-96 % due to the formation of a low-boiling point, water-ethanol azeotrope. To improve the use of ethanol as a fuel, many methods, such as dehydration, have been proposed to avoid distillation and improve the energy efficiency of extraction. Glucose-based silica, as an adsorbent, was prepared using a simple method, and was proposed for the adsorption of water from water-ethanol mixtures. After adsorption using 0.4 g of adsorbent for 3 h, the initial water concentration of 20 % (water, v/v) was decreased to 10 % (water, v/v). For water concentrations less than 5 % (water, v/v), the adsorbent could concentrate ethanol to 99 % (ethanol, v/v). The Langmuir isotherms used to describe the adsorption of water on an adsorbent showed a correlation coefficient of 0.94. The separation factor of the adsorbent also decreased with decreasing concentration of water in solution.

Exchange of adsorbed H2O and CO2 between the regolith and atmosphere of Mars caused by changes in surface insolation

NASA Technical Reports Server (NTRS)

Fanale, F. P.; Cannon, W. A.

1974-01-01

Estimates have been made of the capacity of the Martian regolith to exchange adsorbed H2O and CO2 with the atmosphere-plus-cap system (APCS). These estimates are based upon measured isotherms for H2O and CO2 adsorption on pulverized basalt at low temperatures and on theoretical considerations. A unit column (1 sq cm) of regolith with a deep subsurface temperature of -77 C, considered average for the disk, will contain about 0.4 g of adsorbed CO2 and about 1 g of adsorbed H2O per meter of depth. Under favorable circumstances the top 3 cm can exchange much more H2O with the lower atmosphere each day than is necessary to produce the diurnal brightening. The process appears to be seasonally reversible. The total regolith may contain, in the adsorbed phase alone, as much as 1% of the H2O and 5% of the CO2 surface inventories expected for a hypothetical Mars that has experienced degassing as intensive as that of earth.

Adsorption of dimethyl trisulfide from aqueous solution on a low-cost adsorbent: thermally activated pinecone

NASA Astrophysics Data System (ADS)

Shang, Jingge; He, Wei; Fan, Chengxin

2015-01-01

Thermally activated pinecone (TAP) was used for the adsorption of dimethyl trisulfide (DMTS) from aqueous solutions, which was proved to be the main odorous in algae-caused black bloom. The effects of adsorbent dosage, adsorbate concentration and contact time on DMTS biosorption were studied. The TAP produced at 600°C exhibited a relatively high surface area (519.69 m2/g) and excellent adsorption capacity. The results show that the adsorption of DMTS was initially fast and that the equilibrium time was 6 h. Higher initial DMTS concentrations led to lower removal percentages but higher adsorption capacity. The removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent dosage. The adsorption process conforms well to a pseudo-second-order kinetics model. The adsorption of DMTS is more appropriately described by the Freundlich isotherm ( R 2 =0.996 1) than by the Langmuir isotherm ( R 2 =0.916 9). The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.

Micromotor-based lab-on-chip immunoassays

NASA Astrophysics Data System (ADS)

García, Miguel; Orozco, Jahir; Guix, Maria; Gao, Wei; Sattayasamitsathit, Sirilak; Escarpa, Alberto; Merkoçi, Arben; Wang, Joseph

2013-01-01

Here we describe the first example of using self-propelled antibody-functionalized synthetic catalytic microengines for capturing and transporting target proteins between the different reservoirs of a lab-on-a-chip (LOC) device. A new catalytic polymer/Ni/Pt microtube engine, containing carboxy moieties on its mixed poly(3,4-ethylenedioxythiophene) (PEDOT)/COOH-PEDOT polymeric outermost layer, is further functionalized with the antibody receptor to selectively recognize and capture the target protein. The new motor-based microchip immunoassay operations are carried out without any bulk fluid flow, replacing the common washing steps in antibody-based protein bioassays with the active transport of the captured protein throughout the different reservoirs, where each step of the immunoassay takes place. A first microchip format involving an `on-the-fly' double-antibody sandwich assay (DASA) is used for demonstrating the selective capture of the target protein, in the presence of excess of non-target proteins. A secondary antibody tagged with a polymeric-sphere tracer allows the direct visualization of the binding events. In a second approach the immuno-nanomotor captures and transports the microsphere-tagged antigen through a microchannel network. An anti-protein-A modified microengine is finally used to demonstrate the selective capture, transport and convenient label-free optical detection of a Staphylococcus aureus target bacteria (containing proteinA in its cell wall) in the presence of a large excess of non-target (Saccharomyces cerevisiae) cells. The resulting nanomotor-based microchip immunoassay offers considerable potential for diverse applications in clinical diagnostics, environmental and security monitoring fields.Here we describe the first example of using self-propelled antibody-functionalized synthetic catalytic microengines for capturing and transporting target proteins between the different reservoirs of a lab-on-a-chip (LOC) device. A new catalytic polymer/Ni/Pt microtube engine, containing carboxy moieties on its mixed poly(3,4-ethylenedioxythiophene) (PEDOT)/COOH-PEDOT polymeric outermost layer, is further functionalized with the antibody receptor to selectively recognize and capture the target protein. The new motor-based microchip immunoassay operations are carried out without any bulk fluid flow, replacing the common washing steps in antibody-based protein bioassays with the active transport of the captured protein throughout the different reservoirs, where each step of the immunoassay takes place. A first microchip format involving an `on-the-fly' double-antibody sandwich assay (DASA) is used for demonstrating the selective capture of the target protein, in the presence of excess of non-target proteins. A secondary antibody tagged with a polymeric-sphere tracer allows the direct visualization of the binding events. In a second approach the immuno-nanomotor captures and transports the microsphere-tagged antigen through a microchannel network. An anti-protein-A modified microengine is finally used to demonstrate the selective capture, transport and convenient label-free optical detection of a Staphylococcus aureus target bacteria (containing proteinA in its cell wall) in the presence of a large excess of non-target (Saccharomyces cerevisiae) cells. The resulting nanomotor-based microchip immunoassay offers considerable potential for diverse applications in clinical diagnostics, environmental and security monitoring fields. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr32400h

Preparation of calcium hydroxyapatite nanoparticles using microreactor and their characteristics of protein adsorption.

PubMed

Kandori, Kazuhiko; Kuroda, Tomohiko; Togashi, Shigenori; Katayama, Erika

2011-02-03

The calcium hydroxyapatite Ca(10)(PO(4))(6)(OH)(2) (Hap) nanoparticles were prepared by using microreactor and employed these Hap nanoparticles to clarify the adsorption behavior of proteins. The size of Hap particles produced by the microreactor reduced in the order of a hardness of the reaction conditions for mixing Ca(OH)(2) and H(3)PO(4) aqueous solutions, such as flow rates of both solutions and temperature. Finally, the size of the smallest Hap nanoparticle became 2 × 15 nm(2), similar to that of BSA molecule (4 × 14 nm(2)). It is noteworthy that the smallest Hap nanoparticles still possesses rodlike shape, suggesting that particles are grown along c-axis even though the reactants mixed very rapidly in narrow channels of the microreactors. The X-ray diffraction patterns of the Hap nanoparticles revealed that the crystallinity of the materials produced by the microreactor is low. The FTIR measurement indicated that the Hap nanoparticles produced by microreactor were carbonate-substituted type B Hap, where the carbonate ions replace the phosphate ions in the crystal lattice. All the adsorption isotherms of acidic bovine serum albumin (BSA), neutral myoglobin (MGB), and basic lysozyme (LSZ) onto Hap nanoparticles from 1 × 10(-4) mol/dm(3) KCl solution were the Langmuirian type. The saturated amounts of adsorbed BSA (n(S)(BSA)) for the Hap nanoparticles produced by microreactor were decreased with decrease in the mean particle length, and finally it reduced to zero for the smallest Hap nanoparticles. Similar results were observed for the adsorption of LSZ; the saturated amounts of adsorbed LSZ (n(S)(LSZ)) also reduced to zero for the smallest Hap nanoparticles. However, in the case of MGB, the saturated mounts of adsorbed MGB (n(S)(MGB)) are also depressed with decreased in their particle size, but about half of MGB molecules still adsorbed onto the smallest Hap nanoparticles. This difference in the protein adsorption behavior was explained by the difference in the size and flexibility of three kinds of proteins. The reduction of n(S)(BSA) is due to the decrease in the fraction of C sites on the side face of each Hap nanoparticle; i.e., there is not enough area left on the nanoparticle surface to adsorb large BSA molecules even though the BSA molecules are soft and their conformations are alterable. The reduction of n(S)(LSZ) was explained by the reduction of P sites. Further, rigidity of the LSZ molecules was given another possibility of the depression of n(S)(LSZ) for the Hap nanoparticles. However, MGB molecules with small and soft structure were adsorbed on the Hap nanoparticle surface by changing their conformation. We could control the amounts of adsorbed proteins by changing the particle size of Hap in the nanometer range and kinds of proteins. These obtained results may be useful for developing biomimetic materials for bone grafts and successful surgical devices in the biochemical field.

Hydrocolloid liquid-core capsules for the removal of heavy-metal cations from water.

PubMed

Nussinovitch, A; Dagan, O

2015-12-15

Liquid-core capsules with a non-crosslinked alginate fluidic core surrounded by a gellan membrane were produced in a single step to investigate their ability to adsorb heavy metal cations. The liquid-core gellan-alginate capsules, produced by dropping alginate solution with magnesium cations into gellan solution, were extremely efficient at adsorbing lead cations (267 mg Pb(2+)/g dry alginate) at 25 °C and pH 5.5. However, these capsules were very weak and brittle, and an external strengthening capsule was added by using magnesium cations. The membrane was then thinned with the surfactant lecithin, producing capsules with better adsorption attributes (316 mg Pb(+2)/g dry alginate vs. 267 mg Pb(+2)/g dry alginate without lecithin), most likely due to the thinner membrane and enhanced mass transfer. The capsules' ability to adsorb other heavy-metal cations - copper (Cu(2+)), cadmium (Cd(2+)) and nickel (Ni(2+)) - was tested. Adsorption efficiencies were 219, 197 and 65 mg/g, respectively, and were correlated with the cation's affinity to alginate. Capsules with the sorbed heavy metals were regenerated by placing in a 1M nitric acid suspension for 24h. Capsules could undergo three regeneration cycles before becoming damaged. Copyright © 2015 Elsevier B.V. All rights reserved.

Foam adsorption as an ex situ capture step for surfactants produced by fermentation.

PubMed

Anic, Iva; Nath, Arijit; Franco, Pedro; Wichmann, Rolf

2017-09-20

In this report, a method for a simultaneous production and separation of a microbially synthesized rhamnolipid biosurfactant is presented. During the aerobic cultivation of flagella-free Pseudomonas putida EM383 in a 3.1L stirred tank reactor on glucose as a sole carbon source, rhamnolipids are produced and excreted into the fermentation liquid. Here, a strategy for biosurfactant capture from rhamnolipid enriched fermentation foam using hydrophobic-hydrophobic interaction was investigated. Five adsorbents were tested independently for the application of this capture technique and the best performing adsorbent was tested in a fermentation process. Cell-containing foam was allowed to flow out of the fermentor through the off-gas line and an adsorption packed bed. Foam was observed to collapse instantly, while the resultant liquid flow-through, which was largely devoid of the target biosurfactant, eluted towards the outlet channel of the packed bed column and was subsequently pumped back into the fermentor. After 48h of simultaneous fermentation and ex situ adsorption of rhamnolipids from the foam, 90% out of 5.5g of total rhamnolipids produced were found in ethanol eluate of the adsorbent material, indicating the suitability of this material for ex situ rhamnolipid capture from fermentation processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Anharmonic Effects on the Electron-Energy Spectra of Surface Vibrations

NASA Astrophysics Data System (ADS)

Ariyasu, Janice Carol

First, we consider the effect of lateral interactions on double losses and overtones in electron-energy-loss studies of surface vibrations. We develop a theory of two-phonon losses in the dipole-dominated regime of small -angle scattering. Our calculation employs the simple model of an ordered overlayer of molecules adsorbed on a crystal surface. With this model, we can identify two features; one which corresponds to the double loss and another which corresponds the excitation of an overtone. We then study the role of lateral interactions in each. We find that the presence of lateral interactions affects the position of the overtone relative to the double loss, and influences both its width and shape. The implications of these results are discussed, particularly as they relate to estimates of dissociation energies by the Birge-Sponer procedure. Next, we consider the anharmonic damping of adsorbate vibrations, with specific applications to species (S, O, and CO) adsorbed on the Ni(100) and Ni(111) surfaces. Our attention is restricted to adsorbate modes that can decay by two-phonon processes to one substrate phonon and either another substrate mode phonon or to a phonon of a mode that is localized on the adsorbate. The magnitude and temperature variation of the linewidth of adsorbate modes by this mechanism is explored; we find that near room temperature the calculated linewidths vary linearly with temperature. We also simulate the inhomogeneous broadening produced by disorder by considering the eigenfrequencies of infrared -active modes. Finally, we consider the diffuse scattering of electrons from surfaces by long-wavelength, acoustic phonons. The mechanism that we explore is the modulation of the image potential from ripples induced in the surface profile by thermally-excited surface and bulk phonons. We compare our results with earlier studies, and with the scattering produced by the dynamic-dipole moment of the surface atoms.

Functional differentiation of human pluripotent stem cells on a chip.

PubMed

Giobbe, Giovanni G; Michielin, Federica; Luni, Camilla; Giulitti, Stefano; Martewicz, Sebastian; Dupont, Sirio; Floreani, Annarosa; Elvassore, Nicola

2015-07-01

Microengineering human "organs-on-chips" remains an open challenge. Here, we describe a robust microfluidics-based approach for the differentiation of human pluripotent stem cells directly on a chip. Extrinsic signal modulation, achieved through optimal frequency of medium delivery, can be used as a parameter for improved germ layer specification and cell differentiation. Human cardiomyocytes and hepatocytes derived on chips showed functional phenotypes and responses to temporally defined drug treatments.

Recent advances in microparticle continuous separation.

PubMed

Kersaudy-Kerhoas, M; Dhariwal, R; Desmulliez, M P Y

2008-03-01

Recent advances in microparticle separation in continuous flow are presented. It is intended for scientists in the field of separation science in biology, chemistry and microsystems engineering. Recent techniques of micron-sized particle separation within microsystems are described with emphasis on five different categories: optical, magnetic, fluidic-only, electrical and minor separation methods. Examples from the growing literature are explained with insights on separation efficiency and microengineering challenges. Current applications of the techniques are discussed.

Thermoelctric Properties of Bi and Bismuth Telluride Composites

NASA Astrophysics Data System (ADS)

Huber, Tito E.; Calcao, Ricky

1998-03-01

It has been suggested that microengineering traditional thermoelectric materials into composites may leadto asignificant improvement in their thermoelectric performance. One approach for the fabrication of nanostructured materials is the utilization of nanochannel insulators as a matrix for the synthesis of dense composites using high pressure injection of the melt. We will discuss the synthesis and structural properties of oriented Bi and Bismuth Telluride wire arrays prepared with this technique. Funded by the Army Research Office.

Enzymatic Fuel Cells: Towards Self-Powered Implantable and Wearable Diagnostics.

PubMed

Gonzalez-Solino, Carla; Lorenzo, Mirella Di

2018-01-29

With the rapid progress in nanotechnology and microengineering, point-of-care and personalised healthcare, based on wearable and implantable diagnostics, is becoming a reality. Enzymatic fuel cells (EFCs) hold great potential as a sustainable means to power such devices by using physiological fluids as the fuel. This review summarises the fundamental operation of EFCs and discusses the most recent advances for their use as implantable and wearable self-powered sensors.

Laser Material Processing for Microengineering Applications

NASA Technical Reports Server (NTRS)

Helvajian, H.

1995-01-01

The processing of materials via laser irradiation is presented in a brief survey. Various techniques currently used in laser processing are outlined and the significance to the development of space qualified microinstrumentation are identified. In general the laser processing technique permits the transferring of patterns (i.e. lithography), machining (i.e. with nanometer precision), material deposition (e.g., metals, dielectrics), the removal of contaminants/debris/passivation layers and the ability to provide process control through spectroscopy.

Creation and Optimization of Novel Solar Cell Power via Bimaterial Piezoelectric MEMS Device

DTIC Science & Technology

2011-12-01

piezoelectric mechanical vibration energy harvesters ,” Integrated Ferroelectrics, vol. 71, pp. 121–160, 2005. [32] Y. C. Shu, I. C. Lien, “Efficiency of...energy conversion for a piezoelectric power harvesting system.” Journal of Micromechanics and Microengineering, vol. 16, pp. 2429–2438, 2006. [33] C. D...maximum efficiency for piezoelectric vibrations occurs at the natural, or resonant, frequency for the referenced material. If the alternative

Enzymatic Fuel Cells: Towards Self-Powered Implantable and Wearable Diagnostics

PubMed Central

Gonzalez-Solino, Carla; Lorenzo, Mirella Di

2018-01-01

With the rapid progress in nanotechnology and microengineering, point-of-care and personalised healthcare, based on wearable and implantable diagnostics, is becoming a reality. Enzymatic fuel cells (EFCs) hold great potential as a sustainable means to power such devices by using physiological fluids as the fuel. This review summarises the fundamental operation of EFCs and discusses the most recent advances for their use as implantable and wearable self-powered sensors. PMID:29382147

Poly(L-lysine) Interfaces via Dual Click Reactions on Surface-Bound Custom-Designed Dithiol Adsorbates.

PubMed

Shakiba, Amin; Jamison, Andrew C; Lee, T Randall

2015-06-09

Surfaces modified with poly(L-lysine) can be used to immobilize selected biomolecules electrostatically. This report describes the preparation of a set of self-assembled monolayers (SAMs) from three different azide-terminated adsorbates as platforms for performing controlled surface attachments and as a means of determining the parameters that afford stable poly(L-lysine)-modified SAM surfaces having controlled packing densities. A maleimide-terminated alkyne linker was "clicked" to the azide-terminated surfaces via a copper-catalyzed cycloaddition reaction to produce the attachment sites for the polypeptides. A thiol-Michael addition was then used to immobilize cysteine-terminated poly(L-lysine) moieties on the gold surface, avoiding adsorbate self-reactions with this two-step procedure. Each step in this process was analyzed by ellipsometry, X-ray photoelectron spectroscopy, polarization modulation infrared reflection-absorption spectroscopy, and contact angle goniometry to determine which adsorbate structure most effectively produced the targeted polypeptide interface. Additionally, a series of mixed SAMs using an azidoalkanethiol in combination with a normal alkanethiol having an equivalent alkyl chain were prepared to provide data to determine how dilution of the azide reactive site on the SAM surface influences the initial click reaction. Overall, the collected data demonstrate the advantages of an appropriately designed bidentate absorbate and its potential to form effective platforms for biomolecule surface attachment via click reactions.

Surface Oxide Net Charge of a Titanium Alloy ; Modulation of Fibronectin-Activated Attachment and Spreading of Osteogenic Cells

PubMed Central

Rapuano, Bruce E.; MacDonald, Daniel E.

2010-01-01

In the current study, we have altered the surface oxide properties of a Ti6Al4V alloy using heat treatment or radiofrequency glow discharge (RFGD) in order to evaluate the relationship between the physico-chemical and biological properties of the alloy's surface oxide. The effects of surface pretreatments on the attachment of cells from two osteogenic cell lines (MG63 and MC3T3) and a mesenchymal stem cell line (C3H10T1/2) to fibronectin adsorbed to the alloy were measured. Both heat and RFGD pretreatments produced a several-fold increase in the number of cells that attached to fibronectin adsorbed to the alloy (0.001 and 10 nM FN) for each cell line tested. An antibody (HFN7.1) directed against the central integrin binding domain of fibronectin produced a 65-70% inhibition of cell attachment to fibronectin-coated disks, incdicating that cell attachment to the metal discs was dependent on fibronectin binding to cell integrin receptors. Both treatments also accelerated the cell spreading response manifested by extensive flattening and an increase in mean cellular area. The treatment-induced increases in the cell attachment activity of adsorbed fibronectin were correlated with previously demonstrated increases in Ti6Al4V oxide negative net surface charge at physiological pH produced by both heat and RFGD pretreatments. Since neither treatment increased the adsorption mass of fibronectin, these findings suggest that negatively charged surface oxide functional groups in Ti6Al4V can modulate fibronectin's integrin receptor activity by altering the adsorbed protein's conformation. Our results further suggest that negatively charged functional groups in the surface oxide can play a prominent role in the osseointegration of metallic implant materials. PMID:20884181

Arresting relaxation in Pickering Emulsions

NASA Astrophysics Data System (ADS)

Atherton, Tim; Burke, Chris

2015-03-01

Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

Demonstration of Metabolic Heat Regenerated Temperature Swing Adsorption Technology

NASA Technical Reports Server (NTRS)

Paul, Heather; Iacomini, Christine; Powers, Aaron; Dunham, Jonah; Straub-Lopez, Katie; Anerson, Grant; MacCallum, Taber

2007-01-01

Patent-pending Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is currently being investigated for removal and rejection of CO2 and heat from a Portable Life Support System (PLSS) to a Martian environment. The metabolically-produced CO2 present in the vent loop gas is collected using a CO2 selective adsorbent that has been cooled via a heat exchanger to near CO2 sublimation temperatures (approx.195K) with liquid CO2 obtained from Martian resources. Once the adsorbent is fully loaded, fresh warm, moist vent loop (approx.300K) is used to heat the adsorbent via another heat exchanger. The adsorbent will then reject the collected CO2 to the Martian ambient. Two beds are used to achieve continuous CO2 removal by cycling between the cold and warm conditions for adsorbent loading and regeneration, respectively. Small experiments have already been completed to show that an adsorbent can be cycled between these PLSS operating conditions to provide adequate conditions for CO2 removal from a simulated vent loop. One of the remaining technical challenges is extracting enough heat from the vent loop to warm the adsorbent in an appreciable time frame to meet the required adsorb/desorb cycle. The other key technical aspect of the technology is employing liquid CO2 to achieve the appropriate cooling. A technology demonstrator has been designed, built and tested to investigate the feasibility of 1) warming the adsorbent using the moist vent loop, 2) cooling the adsorbent using liquid CO2, and 3) using these two methods in conjunction to successfully remove CO2 from a vent loop and reject it to Mars ambient. Both analytical and numerical methods were used to perform design calculations and trades. The demonstrator was built and tested. The design analysis and testing results are presented along with recommendations for future development required to increase the maturity of the technology.

Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder-Metallurgy-Produced Titanium Alloys

NASA Astrophysics Data System (ADS)

Muth, T. R.; Yamamoto, Y.; Frederick, D. A.; Contescu, C. I.; Chen, W.; Lim, Y. C.; Peter, W. H.; Feng, Z.

2013-05-01

An investigation was undertaken using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas-forming species. PM-titanium made from revert scrap, where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal and minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders are critical for achieving equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

Tetracycline removal from water by adsorption/bioadsorption on activated carbons and sludge-derived adsorbents.

PubMed

Rivera-Utrilla, José; Gómez-Pacheco, Carla V; Sánchez-Polo, Manuel; López-Peñalver, Jesús J; Ocampo-Pérez, Raúl

2013-12-15

The objective of this study was to analyze the behavior of activated carbons with different chemical and textural natures in the adsorption of three tetracyclines (TCs) (tetracycline, oxytetracycline, and chlortetracycline). We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by the combined use of microorganisms and activated carbon (bioadsorption). Sludge-derived materials were also used to remove TC from water. The capacity of these materials to adsorb TC was very high and was much greater than that of commercial activated carbon. This elevated adsorption capacity (512.1-672.0 mg/g) is explained by the high tendency of TC to form complex ions with some of the metal ions present in these materials. The medium pH and presence of electrolytes considerably affected TCs adsorption on commercial activated carbon. These results indicate that electrostatic adsorbent-adsorbate interactions play an important role in TC adsorption processes when conducted at pH values that produce TC deprotonation. The presence of bacteria during the TCs adsorption process decreases their adsorption/bioadsorption on the commercial activated carbon, weakening interactions between the adsorbate and the microfilm formed on the carbon surface. The adsorptive capacity was considerably lower in dynamic versus static regime, attributable to problems of TC diffusion into carbon pores and the shorter contact time between adsorbate and adsorbent. Copyright © 2013 Elsevier Ltd. All rights reserved.

Separation of [(99m)Tc]pertechnetate and molybdate using polyethylene glycol coated C18 and C30 resins.

PubMed

Andersson, J D; Wilson, J S; Romaniuk, J A; McEwan, A J B; Abrams, D N; McQuarrie, S A; Gagnon, K

2016-04-01

Hydrophobic adsorbents such as C18 and C30 were coated with PEG and subsequently used for the separation of Mo/Tc. The most effective resin for adsorbing PEG was the C18-U resin, which demonstrated a coating capacity of 97.6±2.8mg PEG per g of resin. The ability to adsorb pertechnetate was proportional to the amount of PEG coated on the hydrophobic resin. The [(99m)Tc]pertechnetate recovery during the separation of cyclotron produced (99m)Tc from (100)Mo was 91.8±0.3% (n=2). The resultant product met relevant USP monograph specifications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fabrication and Characterization of Immobilized Biosurfactant Produced by Pseudomonas aeruginosa Grown on Cassava Industrial Wastewater into Activated Allophane as an Adsorbent

NASA Astrophysics Data System (ADS)

Suryanti, V.; Widjonarko, D. M.; Windrawati; Widyaningsih, V.

2017-02-01

The immobilization of biosurfactant into activated allophane has been conducted with mass ratio of biosurfactant:allophane of 1:5; 1:7 and 1:10 and contact time of 24 and 48 h. The optimum condition for immobilization was reached when the mass ratio of biosurfactant: allophane of 1:10 with the contact time of 24 h was applied. The result yielded the immobilization product having the specific surface area of 82.42 m2/g and the surface acidity of 9.12 mmol/g. A better adsorbent has been produced. In respect to the activated allophane, there was a decreasing of specific surface area about 20% and increasing of surface acidity value about 120%.

Selected papers from the 7th International Conference on Microtechnologies in Medicine and Biology (MMB 2013)

NASA Astrophysics Data System (ADS)

Meng, Ellis; Takayama, Shuichi

2014-03-01

In this special section of Journal of Micromechanics and Microengineering are a collection of the best microengineering papers presented at the 7th International Conference on Microtechnologies in Medicine and Biology (MMB 2013) which took place in the seaside town of Marina del Rey, California, USA on 10-12 April, 2013. During the 3-day conference, participants enjoyed talks from 6 invited keynote speakers and 125 flash oral/poster presentations. The MMB conference is a biennial meeting with the primary purpose of fostering interactions between biologists and medical researchers, clinicians, chemists, physicists and engineers to enhance and strengthen the potential microtechnologies that will revolutionize the fields of medicine and biological sciences. The conference possesses a unique format where all poster presenters provide a brief 60 s oral presentation highlighting their research. This format was devised to provide training and exposure for young researchers, especially PhD students and postdocs, in the field and stimulate interdisciplinary exchanges. Therefore, MMB provides an intimate intellectual venue the facilitate discussions and collaborations to advance new research tools and technologies for medicine and biological sciences. The MMB conference series was co-founded by Professor David Beebe (University of Wisconsin—Madison) and Professor André Dittmar (University of Lyon) and was the first international meeting to provide a forum focusing on emerging applications of microtechnologies to unmet needs in medicine and biology. The series was held for the first time in 2000, in Lyon, France and followed by Madison, USA (2002), Oahu Island in Hawaii, USA (2005), Okinawa, Japan (2006), Québec City, Canada (2009), Lucerne, Switzerland (2011), and Marina del Rey, USA (2013). The next conference will be held in Seoul, Korea in 2015. This collection of articles highlights recent progress in microtechnologies with medical and biological applications. We are grateful to the many authors who contributed their research achievements to this exciting issue and to the anonymous reviewers for their invaluable insights and suggestions. We would also like to express our thanks to our colleagues on the international steering committee for their dedicated review of the selected presentations that appears at the conference. Finally, we appreciate the support of the editorial staff of Journal of Micromechanics and Microengineering for this inaugural MMB special issue. We look forward to continued collaboration in future MMB conferences.

Investigation of the Effluents Produced during the Functioning of Black and White Colored Smoke Devices.

DTIC Science & Technology

1986-01-31

and 4% diatomaceous earth (binder). Modified EPA Method 5 Sampling Train F The modified EPA Method 5 sampling train used was similar to the one...the fiber glass filter paper were taken by the Amberlite XAD-2. The XAD-2 is a porous polymer adsorbent used to sample organic vapors in effluents...from different kinds of combustion processes. Although a careful clean-up procedure was taken to wash the adsorbents before using, the polymer may still

Perfectly monodisperse micro-bubble production by novel mechanical means. Scaling laws.

NASA Astrophysics Data System (ADS)

Ganan-Calvo, Alfonso M.; Gordillo, Jose M.; Ouarti, Nawel; Prevost, Thomas; Sampedro, Jose L.

2000-11-01

A continuous stream of controllable, perfectly homogeneous size micro-bubbles (of the order of some microns and larger) can be produced by a novel, extremely simple mechanical means that we call "Flow Focusing" (e.g. see Ganan-Calvo 1998, Phys. Rev. Lett. vol. 80, 285). Using this technique, a capillary gas micro-jet is formed ("focused") by a co-flowing stream of liquid forced through a sub-millimetric orifice. This gas micro-jet undergoes a rapid capillary breakup (e.g. Chandrasekhar 1961 "Hydrodynamic and Hydromagnetic Stability", p. 541) with a strong frequency "self-locking" effect. In this work we present a theoretical model which predicts the micro-bubble size as a function of the physical and geometrical parameters of the system. A complete experimental study is also provided, and the raw data are collapsed into a universal scaling law given by our theoretical model. This novel micro-fluidics phenomenon may have a wide variety of applications ranging from bio-medicine, pharmaceutical specialities, food industry, and even for the mesoscale micro-templating of micro-engineered materials (i.e. photonic crystals, smart materials, etc.).

Liver regenerative medicine: advances and challenges.

PubMed

Chistiakov, Dimitry A

2012-01-01

Liver transplantation is the standard care for many end-stage liver diseases. However, donor organs are scarce and some people succumb to liver failure before a donor is found. Liver regenerative medicine is a special interdisciplinary field of medicine focused on the development of new therapies incorporating stem cells, gene therapy and engineered tissues in order to repair or replace the damaged organ. In this review we consider the emerging progress achieved in the hepatic regenerative medicine within the last decade. The review starts with the characterization of liver organogenesis, fetal and adult stem/progenitor cells. Then, applications of primary hepatocytes, embryonic and adult (mesenchymal, hematopoietic and induced pluripotent) stem cells in cell therapy of liver diseases are considered. Current advances and challenges in producing mature hepatocytes from stem/progenitor cells are discussed. A section about hepatic tissue engineering includes consideration of synthetic and natural biomaterials in engineering scaffolds, strategies and achievements in the development of 3D bioactive matrices and 3D hepatocyte cultures, liver microengineering, generating bioartificial liver and prospects for fabrication of the bioengineered liver. Copyright © 2012 S. Karger AG, Basel.

In vitro spatially organizing the differentiation in individual multicellular stem cell aggregates.

PubMed

Qi, Hao; Huang, Guoyou; Han, Yu Long; Lin, Wang; Li, Xiujun; Wang, Shuqi; Lu, Tian Jian; Xu, Feng

2016-01-01

With significant potential as a robust source to produce specific somatic cells for regenerative medicine, stem cells have attracted increasing attention from both academia and government. In vivo, stem cell differentiation is a process under complicated regulations to precisely build tissue with unique spatial structures. Since multicellular spheroidal aggregates of stem cells, commonly called as embryoid bodies (EBs), are considered to be capable of recapitulating the events in early stage of embryonic development, a variety of methods have been developed to form EBs in vitro for studying differentiation of embryonic stem cells. The regulation of stem cell differentiation is crucial in directing stem cells to build tissue with the correct spatial architecture for specific functions. However, stem cells within the three-dimensional multicellular aggregates undergo differentiation in a less unpredictable and spatially controlled manner in vitro than in vivo. Recently, various microengineering technologies have been developed to manipulate stem cells in vitro in a spatially controlled manner. Herein, we take the spotlight on these technologies and researches that bring us the new potential for manipulation of stem cells for specific purposes.

A Review of 3D Printing Techniques and the Future in Biofabrication of Bioprinted Tissue.

PubMed

Patra, Satyajit; Young, Vanesa

2016-06-01

3D printing has been around in the art, micro-engineering, and manufacturing worlds for decades. Similarly, research for traditionally engineered skin tissue has been in the works since the 1990s. As of recent years, the medical field also began to take advantage of the untapped potential of 3D printing for the biofabrication of tissue. To do so, researchers created a set of goals for fabricated tissues based on the characteristics of natural human tissues and organs. Fabricated tissue was then measured against this set of standards. Researchers were interested in not only creating tissue that functioned like natural tissues but in creating techniques for 3D printing that would print tissues quickly, efficiently, and ultimately result in the ability to mass produce fabricated tissues. Three promising methods of 3D printing emerged from their research: thermal inkjet printing with bioink, direct-write bioprinting, and organ printing using tissue spheroids. This review will discuss all three printing techniques, as well as their advantages, disadvantages, and the possibility of future advancements in the field of tissue fabrication.

Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, Li-Jung; Pan, Horng-Bin; Wai, Chien M.

The ability to re-use amidoxime-based polymeric adsorbents is a critical component in reducing the overall cost of the technology to extract uranium from seawater. This report describes an evaluation of adsorbent reusability in multiple re-use (adsorption/stripping) cycles in real seawater exposures with potassium bicarbonate (KHCO3) elution using several amidoxime-based polymeric adsorbents. The KHCO3 elution technique achieved ~100% recovery of uranium adsorption capacity in the first re-use. Subsequent re-uses showed significant drops in adsorption capacity. After the 4th re-use with the ORNL AI8 adsorbent, the 56-day adsorption capacity dropped to 28% of its original capacity. FTIR spectra revealed that there wasmore » a conversion of the amidoxime ligands to carboxylate groups during extended seawater exposure, becoming more significant with longer the exposure time. Ca and Mg adsorption capacities also increased with each re-use cycle supporting the hypothesis that long term exposure resulted in converting amidoxime to carboxylate, enhancing the adsorption of Ca and Mg. Shorter seawater exposure (adsorption/stripping) cycles (28 vs. 42 days) had higher adsorption capacities after re-use, but the shorter exposure cycle time did not produce an overall better performance in terms of cumulative exposure time. Recovery of uranium capacity in re-uses may also vary across different adsorbent formulations. Through multiple re-use the adsorbent AI8 can harvest 10 g uranium/kg adsorbent in ~140 days, using a 28-day adsorption/stripping cycle, a performance much better than would be achieved with a single use of the adsorbent through very long-term exposure (saturation capacity = 7.4 g U/kg adsorbent). A time dependent seawater exposure model to evaluate the cost associated with reusing amidoxime-based adsorbents in real seawater exposures was developed. The cost to extract uranium from seawater ranged from $610-830/kg U was predicted. Model simulation suggests that a short seawater exposure cycle (< 15 days) is the optimal deployment period for lower uranium production cost in seawater uranium mining.« less

Amine-functionalized mesoporous ZSM-5 zeolite adsorbents for carbon dioxide capture

NASA Astrophysics Data System (ADS)

Wang, Yisong; Du, Tao; Song, Yanli; Che, Shuai; Fang, Xin; Zhou, Lifeng

2017-11-01

ZSM-5 type zeolite with mesoporous structure was prepared and then amine-functionalized with tetraethylenepentamine (TEPA) by wet impregnation method to form a series of CO2 adsorbents (ZTx). The structural properties of ZSM-5 and ZTx were characterized by XRD, FTIR, TGA/DTG, nitrogen adsorption/desorption, SEM and EDX techniques. The adsorption capacity of the adsorbents with different amine loading was measured at a temperature from 40 to 100 °C and the adsorption capacity of ZT7 was 1.80 mmol/g at 100 °C. The adsorption process and mechanism were studied by fitting the experimental data used the three adsorption kinetic models, and a complex physical and chemical mixing process was produced as the amine entered the surface and pore size of the zeolite. The high adsorption selectivity at 10% CO2 concentration and the stability of the five adsorption desorption cycles indicated that ZT7 is a suitable and promising CO2 adsorbent for the purification of industrial flue gas.

Chiral Selective Chemistry Induced by Natural Selection of Spin-Polarized Electrons.

PubMed

Rosenberg, Richard A; Mishra, Debabrata; Naaman, Ron

2015-06-15

The search to understand the origin of homochirality in nature has been ongoing since the time of Pasteur. Previous work has shown that DNA can act as a spin filter for low-energy electrons and that spin-polarized secondary electrons produced by X-ray irradiation of a magnetic substrate can induce chiral selective chemistry. In the present work it is demonstrated that secondary electrons from a substrate that are transmitted through a chiral overlayer cause enantiomeric selective chemistry in an adsorbed adlayer. We determine the quantum yields (QYs) for dissociation of (R)- or (S)-epichlorohydrin adsorbed on a chiral self-assembled layer of DNA on gold and on bare gold (for control). The results show that there is a significant difference in the QYs between the two enantiomers when adsorbed on DNA, but none when they are adsorbed on bare Au. We propose that the effect results from natural spin filtering effects cause by the chiral monolayer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alkali (Li, K and Na) and alkali-earth (Be, Ca and Mg) adatoms on SiC single layer

NASA Astrophysics Data System (ADS)

Baierle, Rogério J.; Rupp, Caroline J.; Anversa, Jonas

2018-03-01

First-principles calculations within the density functional theory (DFT) have been addressed to study the energetic stability, and electronic properties of alkali and alkali-earth atoms adsorbed on a silicon carbide (SiC) single layer. We observe that all atoms are most stable (higher binding energy) on the top of a Si atom, which moves out of the plane (in the opposite direction to the adsorbed atom). Alkali atoms adsorbed give raise to two spin unpaired electronic levels inside the band gap leading the SiC single layer to exhibit n-type semiconductor properties. For alkaline atoms adsorbed there is a deep occupied spin paired electronic level inside the band gap. These finding suggest that the adsorption of alkaline and alkali-earth atoms on SiC layer is a powerful feature to functionalize two dimensional SiC structures, which can be used to produce new electronic, magnetic and optical devices as well for hydrogen and oxygen evolution reaction (HER and OER, respectively). Furthermore, we observe that the adsorption of H2 is ruled by dispersive forces (van der Waals interactions) while the O2 molecule is strongly adsorbed on the functionalized system.

Characteristics of Microactive Carbon from Bamboo Var. Petung as Adsorbent

NASA Astrophysics Data System (ADS)

Wirawan, I. P. S.; Sutrisno; Seminar, K. B.; Nelwan, L. O.

2018-05-01

Bamboo has unique characteristics, such as in the carbonization process at a temperature of 500°C, the carbon characteristics is homogeneous. The characteristics of bamboo have great potential as a future bio-energy resource. Apart from being a bio-energy source of bamboo can also be used as an adsorbent material in the form of activated carbon. Activated carbon is the most inexpensive and easy to produce adsorbent material. One of the activated carbons of bamboo materials used is the micro-active carbon from bamboo. Microactivated carbon bamboo has a pore structure which is good for adsorption because of its surface area being much better than the other adsorbent, mainly on mesopore and micropore pore size. The purpose of this research is to make micro-activated carbon adsorbent bamboo var. petungand to analyze their characteristics. The characteristic of microactivecarbon was analyzed by SEM EDS and Iod number. The result showed a variation in pore size from 1μm to 11.157μm. The surface area of micro-active carbon of 200 mesh and 80 mesh is 1954.95 m2g-1 and 1516.34 m2g-1.

Factors influencing antibiotics adsorption onto engineered adsorbents.

PubMed

Xia, Mingfang; Li, Aimin; Zhu, Zhaolian; Zhou, Qin; Yang, Weiben

2013-07-01

The study evaluated the adsorption of two antibiotics by four engineered adsorbents (hypercrosslinked resin MN-202, macroporous resin XAD-4, activated carbon F-400, and multi-walled carbon nanotubes (MWCNT)) from aqueous solutions. The dynamic results demonstrated the dominant influence of pore size in adsorption. The adsorption amounts of antibiotics on XAD-4 were attributed to the hydrophobic effect, whereas steric hindrance or micropore-filling played a main role in the adsorption of antibiotics by F-400 because of its high microporosity. Aside from F-400, similar patterns of pH-dependent adsorption were observed, implying the importance of antibiotic molecular forms to the adsorption process for adsorbents. Increasing the ionic concentration with CaC12 produced particular adsorption characteristics on MWCNT at pH 2.0 and F-400 at pH 8.0, which were attributed to the highly available contact surfaces and molecular sieving, respectively. Its hybrid characteristics incorporating a considerable portion of mesopores and micropores made hypercross linked MN-202 a superior antibiotic adsorbent with high adsorption capacity. Furthermore, the adsorption capacity of MWCNT on the basis of surface area was more advantageous than that of the other adsorbents because MWCNT has a much more compact molecular arrangement.

Pyrolysis of blended animal manures to produce combustible gas and value-added charcoal adsorbent

USDA-ARS?s Scientific Manuscript database

Blended swine solids, chicken litter, and rye grass were pyrolyzed using a skid-mounted sytem. Produced gas composition was analyzed for major hydrocarbons and S-containing compounds. Charcoal was analyzed for its surface functional groups, contact angles, HHV, and total element contents. Some of th...

Directed 3D Cell Alignment and Elongation in Microengineered Hydrogels

DTIC Science & Technology

2010-01-01

Merok J, Vunjak- Novakovic G, Freed LE. Tissue engineering of functional cardiac muscle: molecular, structural, and electro- physiological studies. Am J...endothelial cells and smooth muscle cells. J Biomech 2004;37(4):531e9. [4] Vunjak- Novakovic G, Altman G, Horan R, Kaplan DL. Tissue engineering of...483e95. [9] Burdick JA, Vunjak- Novakovic G. Engineered microenvironments for controlled stem cell differentiation. Tissue Eng Part A 2009;15(2):205e19

Heterogeneous System-on-a-Chip Design for Self-Powered Wireless Sensor Networks in Non-Benign Environments

DTIC Science & Technology

2008-03-01

Paper CANEUS 2006-11045. [8] S. Janson, A . Huang, W. Hansen, L. Steffeney, and H . Helvajian , “Development of an Inspector Satellite Using...antenna will be required to achieve any meaningful range. Final Report for EOARD Grant FA8655-06-1-3053 53 Bibliography [1] Helvajian , H . and...International Astronautics Federation, Graz, Austria, Oct. 1993, Paper IAF-93-U.5.575 [3] H . Helvajian , Microengineering Aerospace Systems, Reston, VA

Performance Testing of a Microfabricated Propulsion System for Nanosatellite Applications (POSTPRINT)

DTIC Science & Technology

2005-04-22

References [1] Janson S, Helvajian H and Robinson E 1993 The concept of nanosatellite for revolutionary, low-cost space systems 44th International...technologies J. Micromech. Microeng. 8 54–6 [4] Helvajian H 1997 Microengineering Technology for Space Systems (Reston, VA: AIAA) [5] Ketsdever A D 2000 System...nanosatellite applications (POSTPRINT) 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Andrew D. Ketsdever (AFRL/PRSA); Riki H . Lee and

SAM-based cell transfer to photopatterned hydrogels for microengineering vascular-like structures.

PubMed

Sadr, Nasser; Zhu, Mojun; Osaki, Tatsuya; Kakegawa, Takahiro; Yang, Yunzhi; Moretti, Matteo; Fukuda, Junji; Khademhosseini, Ali

2011-10-01

A major challenge in tissue engineering is to reproduce the native 3D microvascular architecture fundamental for in vivo functions. Current approaches still lack a network of perfusable vessels with native 3D structural organization. Here we present a new method combining self-assembled monolayer (SAM)-based cell transfer and gelatin methacrylate hydrogel photopatterning techniques for microengineering vascular structures. Human umbilical vein cell (HUVEC) transfer from oligopeptide SAM-coated surfaces to the hydrogel revealed two SAM desorption mechanisms: photoinduced and electrochemically triggered. The former, occurs concomitantly to hydrogel photocrosslinking, and resulted in efficient (>97%) monolayer transfer. The latter, prompted by additional potential application, preserved cell morphology and maintained high transfer efficiency of VE-cadherin positive monolayers over longer culture periods. This approach was also applied to transfer HUVECs to 3D geometrically defined vascular-like structures in hydrogels, which were then maintained in perfusion culture for 15 days. As a step toward more complex constructs, a cell-laden hydrogel layer was photopatterned around the endothelialized channel to mimic the vascular smooth muscle structure of distal arterioles. This study shows that the coupling of the SAM-based cell transfer and hydrogel photocrosslinking could potentially open up new avenues in engineering more complex, vascularized tissue constructs for regenerative medicine and tissue engineering applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

Artificial enzyme-powered microfish for water-quality testing.

PubMed

Orozco, Jahir; García-Gradilla, Victor; D'Agostino, Mattia; Gao, Wei; Cortés, Allan; Wang, Joseph

2013-01-22

We present a novel micromotor-based strategy for water-quality testing based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants. The new micromotor toxicity testing concept mimics live-fish water testing and relies on the toxin-induced inhibition of the enzyme catalase, responsible for the biocatalytic bubble propulsion of tubular microengines. The locomotion and survival of the artificial microfish are thus impaired by exposure to a broad range of contaminants, that lead to distinct time-dependent irreversible losses in the catalase activity, and hence of the propulsion behavior. Such use of enzyme-powered biocompatible polymeric (PEDOT)/Au-catalase tubular microengine offers highly sensitive direct optical visualization of changes in the swimming behavior in the presence of common contaminants and hence to a direct real-time assessment of the water quality. Quantitative data on the adverse effects of the various toxins upon the swimming behavior of the enzyme-powered artificial swimmer are obtained by estimating common ecotoxicological parameters, including the EC(50) (exposure concentration causing 50% attenuation of the microfish locomotion) and the swimmer survival time (lifetime expectancy). Such novel use of artificial microfish addresses major standardization and reproducibility problems as well as ethical concerns associated with live-fish toxicity assays and hence offers an attractive alternative to the common use of aquatic organisms for water-quality testing.

Bridging the Gap: From 2D Cell Culture to 3D Microengineered Extracellular Matrices.

PubMed

Li, Yanfen; Kilian, Kristopher A

2015-12-30

Historically the culture of mammalian cells in the laboratory has been performed on planar substrates with media cocktails that are optimized to maintain phenotype. However, it is becoming increasingly clear that much of biology discerned from 2D studies does not translate well to the 3D microenvironment. Over the last several decades, 2D and 3D microengineering approaches have been developed that better recapitulate the complex architecture and properties of in vivo tissue. Inspired by the infrastructure of the microelectronics industry, lithographic patterning approaches have taken center stage because of the ease in which cell-sized features can be engineered on surfaces and within a broad range of biocompatible materials. Patterning and templating techniques enable precise control over extracellular matrix properties including: composition, mechanics, geometry, cell-cell contact, and diffusion. In this review article we explore how the field of engineered extracellular matrices has evolved with the development of new hydrogel chemistry and the maturation of micro- and nano- fabrication. Guided by the spatiotemporal regulation of cell state in developing tissues, techniques for micropatterning in 2D, pseudo-3D systems, and patterning within 3D hydrogels will be discussed in the context of translating the information gained from 2D systems to synthetic engineered 3D tissues. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Removing ammonium from water and wastewater using cost-effective adsorbents: A review.

PubMed

Huang, Jianyin; Kankanamge, Nadeeka Rathnayake; Chow, Christopher; Welsh, David T; Li, Tianling; Teasdale, Peter R

2018-01-01

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented. Copyright © 2017. Published by Elsevier B.V.

A DFT Investigation of the Mechanism of Propene Ammoxidation over α-Bismuth Molybdate

DOE PAGES

Licht, Rachel B.; Bell, Alexis T.

2016-11-17

We investigated the mechanisms and energetics for the propene oxidation and ammoxidation occurring on the (010) surface of Bi 2 Mo 3 O 12 using density functional theory (DFT). An energetically feasible sequence of elementary steps for propene oxidation to acrolein, propene ammoxidation to acrylonitrile, and acrolein ammoxidation to acrylonitrile is proposed. Consistent with experimental findings, the rate-limiting step for both propene oxidation and ammoxidation is the initial hydrogen abstraction from the methyl group of propene, which is calculated to have an apparent activation energy of 27.3 kcal/mol. The allyl species produced in this reaction is stabilized as an allylmore » alkoxide, which can then undergo hydrogen abstraction to form acrolein or react with ammonia adsorbed on under-coordinated surface Bi 3+ cations to form allylamine. Dehydrogenation of allylamine is shown to produce acrylonitrile, whereas reaction with additional adsorbed ammonia leads to the formation of acetonitrile and hydrogen cyanide. The dehydrogenation of allyalkoxide species is found to have a significantly higher activation barrier than reaction with adsorbed ammonia, consistent with the observation that very little acrolein is produced when ammonia is present. Finally, we found that rapid reoxidation of the catalyst surface to release wate the driving force for all reactions involving the cleavage of C-H or N-H bonds, because practically all of these steps are endothermic. (Chemical Equation Presented).« less

Decomposition of nitrous oxide and chloromethanes absorbed on particulate matter

NASA Technical Reports Server (NTRS)

Rebbert, R. E.; Ausloos, P. J.

1978-01-01

The effect of pressure on the heterogeneous thermal and pyrolytic decomposition of nitrous oxides adsorbed on sand was studied. Results indicate that N20 adsorbed on certain sand surfaces can be decomposed by photons which nitrous oxide cannot absorb in the gas phase. There is also a thermal heterogeneous decomposition of nitrous oxide which also produces nitrogen. The photolysis of CC14, CFC13, CF2C12 adsorbed on fused quartz and on different types of sand was also investigated. There was no thermal heterogeneous reaction with any of these chloromethanes. Apparently the larger bond energy of approximately 74 kcal for the C-C1 bond compared to approximately 40 kcal for the N-O bond in N2O makes the thermal reaction inoperative for the chloromethanes.

Food wastes derived adsorbents for carbon dioxide and benzene gas sorption.

PubMed

Opatokun, Suraj Adebayo; Prabhu, Azhagapillai; Al Shoaibi, Ahmed; Srinivasakannan, C; Strezov, Vladimir

2017-02-01

Food wastes are produced worldwide in large quantities that could have potential to produce higher value products, including industrial adsorbents. The present work attempts valorization of food waste by CO 2 activation and functionalization through nitric acid and melamine treatment. The prepared porous materials were subjected to gas phase adsorption of CO 2 and benzene gases. The resultant highly porous carbon materials with surface area range from 797 to 1025 m 2 /g were synthesized showing uptake capacities of 4.41, 4.07, 4.18 and 4.36 mmol/g of CO 2 and 345, 305, 242.5 and 380.7 mg/g of C 6 H 6 respectively for PyF515, PyF520, PyF715 and PyF720 in the absence of doped carbon matrix. Differential thermogravimetric (DTG) analysis showed the thermostability of the precursors to validate selected initial pyrolysis temperatures (500 and 700 °C). C 6 H 6 sorption lies mainly in the physisorption region for all adsorbents ensuring re-generation potential. PyF720 and PyF520 recorded the highest isosteric enthalpy of 64.4 kJ/mol and 48.7 kJ/mol respectively, despite the low degree of coverage of the latter. Thus, PyF515 and PyF720 demonstrated the potential for use as sustainable and cost effective adsorbents for benzene gas containment suitable for swing adsorption system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oil shale derived pollutant control materials and methods and apparatuses for producing and utilizing the same

DOEpatents

Boardman, Richard D.; Carrington, Robert A.

2010-05-04

Pollution control substances may be formed from the combustion of oil shale, which may produce a kerogen-based pyrolysis gas and shale sorbent, each of which may be used to reduce, absorb, or adsorb pollutants in pollution producing combustion processes, pyrolysis processes, or other reaction processes. Pyrolysis gases produced during the combustion or gasification of oil shale may also be used as a combustion gas or may be processed or otherwise refined to produce synthetic gases and fuels.

The Effect of Various Acids to the Gelation Process to the Silica Gel Characteristic Using Organic Silica

NASA Astrophysics Data System (ADS)

Rahman, NA; Widiyastuti, W.; Sigit, D.; Ajiza, M.; Sujana, W.

2018-01-01

Bagasse ash is solid waste of cane sugar industry which contain of silica more than 51%. Some previous study of silica gel from bagasse ash have been conducted often and been applied. This study concerns about the effect of various acid used in the process of gelation to the characteristic of silica gel produced. Then, this silica gel will be used as adsorbent. As that, the silica gel must fulfill the requirements of adsorbent, as have good pores characteristics, fit in mesoporous size so that adsorbent diffusion process is not disturbed. A fitted pores size of silica gel can be prepared by managing acid concentration used. The effect of acid, organic acid (tartaric acid) and inorganic acid (hydrochloric acid), is investigated in detail. The acid is added into sodium silicate solution in that the gel is formed, the pores structures can be investigated with BET, the crystal form is analyzed with XRD and the pore structure is analyzed visually with SEM. By managing the acid concentration added, it gets the effect of acid to the pore structure of silica gel. The bigger concentration is, the bigger the pore’s size of silica gel produced.

Adsorption studies of simple gases on As-produced single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Talapatra, Saikat

Adsorption isotherms measurements were used to study films of Xenon (Xe), Argon (Ar), Methane (CH4), Hydrogen (H2) and Neon (Ne) adsorbed on bundles of as-produced Single Walled Carbon Nanotubes (SWNT). A comparison of the specific surface areas of the SWNT samples measured with these various gases, as well as a comparison of the binding energies measured for each of them on the SWNT bundles; allows us to infer which of the possible groups of adsorption sites on the SWNT bundles are actually occupied by the adsorbed gases. The presence of substeps in the first layer isotherm data establishes the existence of different phases within the first layer film. A detailed comparison of our experimental results to recent computer simulations for these systems is done. This allows us to determine the nature of the phases present in the first layer. Evidence of the formation of a one-dimensional phase in the second layer film (i.e. the film that forms after the entire surface of the bundles is covered by one layer of gas) is observed in these studies. The sharpness of this second layer feature varies as a function of the molecular diameter of the adsorbate.

Theoretical investigation of the use of nanocages with an adsorbed halogen atom as anode materials in metal-ion batteries.

PubMed

Razavi, Razieh; Abrishamifar, Seyyed Milad; Rajaei, Gholamreza Ebrahimzadeh; Kahkha, Mohammad Reza Rezaei; Najafi, Meysam

2018-02-21

The applicability of C 44 , B 22 N 22 , Ge 44 , and Al 22 P 22 nanocages, as well as variants of those nanocages with an adsorbed halogen atom, as high-performance anode materials in Li-ion, Na-ion, and K-ion batteries was investigated theoretically via density functional theory. The results obtained indicate that, among the nanocages with no adsorbed halogen atom, Al 22 P 22 would be the best candidate for a novel anode material for use in metal-ion batteries. Calculations also suggest that K-ion batteries which utilize these nanocages as anode materials would give better performance and would yield higher cell voltages than the corresponding Li-ion and Na-ion batteries with nanocage-based anodes. Also, the results for the nanocages with an adsorbed halogen atom imply that employing them as anode materials would lead to higher cell voltages and better metal-ion battery performance than if the nanocages with no adsorbed halogen atom were to be used as anode materials instead. Results further implied that nanocages with an adsorbed F atom would give higher cell voltages and better battery performance than nanocages with an adsorbed Cl or Br atom. We were ultimately able to conclude that a K-ion battery that utilized Al 21 P 22 with an adsorbed F atom as its anode material would afford the best metal-ion battery performance; we therefore propose this as a novel highly efficient metal-ion battery. Graphical abstract The results of a theoretical investigation indicated that Al 22 P 22 is a better candidate for a high-performance anode material in metal-ion batteries than Ge 44 is. Calculations also showed that K-ion batteries with nanocage-based anodes would produce higher cell voltages and perform better than the equivalent Li-ion and Na-ion batteries with nanocage-based anodes, and that anodes based on nanocages with an adsorbed F atom would perform better than anodes based on nanocages with an adsorbed Cl or Br atom.

Recycling of spent adsorbents for oxyanions and heavy metal ions in the production of ceramics.

PubMed

Verbinnen, Bram; Block, Chantal; Van Caneghem, Jo; Vandecasteele, Carlo

2015-11-01

Spent adsorbents for oxyanion forming elements and heavy metals are classified as hazardous materials and they are typically treated by stabilization/solidification before landfilling. The use of lime or cement for stabilization/solidification entails a high environmental impact and landfilling costs are high. This paper shows that mixing spent adsorbents in the raw material for the production of ceramic materials is a valuable alternative to stabilize oxyanion forming elements and heavy metals. The produced ceramics can be used as construction material, avoiding the high economic and environmental impact of stabilization/solidification followed by landfilling. To study the stabilization of oxyanion forming elements and heavy metals during the production process, two series of experiments were performed. In the first series of experiments, the main pollutant, Mo was adsorbed onto iron-based adsorbents, which were then mixed with industrial sludge (3 w/w%) and heated at 1100°C for 30 min. Mo was chosen, as this element is easily adsorbed onto iron-based adsorbents and it is the element that is the most difficult to stabilize (i.e. the highest temperatures need to be reached before the concentrations in the leachate are reduced). Leaching concentration from the 97/3 sludge/adsorbent mixture before heating ranged between 85 and 154 mg/kg; after the heating process they were reduced to 0.42-1.48 mg/kg. Mo was actually stabilized, as the total Mo concentration after addition was not affected by the heat treatment. In the second series of experiments, the sludge was spiked with other heavy metals and oxyanion forming elements (Cr, Ni, Cu, Zn, As, Cd and Pb) in concentrations 5 times higher than the initial concentrations; after heat treatment the leachate concentrations were below the regulatory limit values. The incorporation of spent adsorbents in ceramic materials is a valuable and sustainable alternative to the existing treatment methods, saving raw materials in the ceramics production process and avoiding the use of stabilizing agents. Besides, spent adsorbents added to the raw material for ceramic products, may improve their aesthetic and structural properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-powered microthermionic converter

DOEpatents

Marshall, Albert C.; King, Donald B.; Zavadil, Kevin R.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

2004-08-10

A self-powered microthermionic converter having an internal thermal power source integrated into the microthermionic converter. These converters can have high energy-conversion efficiencies over a range of operating temperatures. Microengineering techniques are used to manufacture the converter. The utilization of an internal thermal power source increases potential for mobility and incorporation into small devices. High energy efficiency is obtained by utilization of micron-scale interelectrode gap spacing. Alpha-particle emitting radioisotopes can be used for the internal thermal power source, such as curium and polonium isotopes.

Polysilicon for everything?

NASA Astrophysics Data System (ADS)

Ward, M. C. L.; McNie, Mark E.; Bunyan, Robert J.; King, David O.; Carline, Roger T.; Wilson, Rebecca; Gillham, J. P.

1998-09-01

We review some of the attractive attributes of microengineering and relate them to features of the highly successful silicon microelectronics industry. We highlight the need for cost effective functionality rather than ultimate performance as a driver for success and review key examples of polysilicon devices from this point of view. The effective exploitation of the data generated by the cost effective polysilicon sensors is also considered and we conclude that `non traditional' data analysis will need to be exploited if full use is to be made of polysilicon devices.

Exact analysis of two kinds of piezoelectric actuator

NASA Astrophysics Data System (ADS)

Rong, Han; Zhifei, Shi

2008-02-01

Two kinds of piezoelectric hollow cylinder actuator are studied in this paper. One is the expansion actuator and the other is the contraction actuator. Using the Airy stress function method, the analytical solutions of these two kinds of actuators are obtained based on the theory of piezo-elasticity. The solutions are compared with numerical results and good agreement is found. Inherent properties of these two kinds of piezoelectric cylinder actuator are presented and discussed. Findings have applications in the field of micromechanics and microengineering.

Satellite-On-A-Chip Feasibility for Distributed Space Missions

DTIC Science & Technology

2006-07-10

S.pdf Satellite Systems Conference and Exhibit, Monterey, [33] H . Helvajian and S. W. Janson, "The Fabrication of a CA, 2004, Paper AIAA-2004-3152. 100...pp. 12-15. 700. [52]0. Yadid-Pecht and R. Etienne-Cummings, CMOS [64]S. W. Janson, H . Helvajian , S. Amimoto, G. Smit, D. Imagers: From...Janson, H . Helvajian , and K. Breuer "MEMS, Hasler, "A 80 p W/frame 104x128 CMOS Imager Microengineering and Aerospace Systems," in Proc. Front End for

An Embedded Fusion Processor

DTIC Science & Technology

2000-10-01

available from rooksj~,rl.af.mil [4] J. Lyke and G. Forman "Microengineering Aerospace Systems" H . Helvajian editor, The Aerospace Press 1999, Chapter 8...e h I O iinterface chip, and Synchronous Dynamic Random 1K-byte. The only consequence is that after the FIFO is Access Memory (SDRAM). Each interface...shown in figure 4a, that will be used for the 1/O interconnects in place of the perimeter bond pads used in the MCM3A. The 6’ h layer is used to

A Low-Cost Femtosatellite to Enable Distributed Space Missions

DTIC Science & Technology

2006-09-20

pdfs/CyroBroSS.pdf Concept in Distributed Space-based Sensing," in Proc. AIAA [36] H . Helvajian and S. W. Janson, "The Fabrication of a 100 gm Defense...press/pressOl.php [21] F. A. Herrero, M. DiJoseph, T. E. Moore, J. A. Slavin, and R. [38] S. W. Janson, H . Helvajian , S. Amimoto, G. Smit, D. Mayer...Congress," [39] H . Helvajian , Microengineering Aerospace Systems, Reston, Subcommittee on Space and Aeronautics, Committee on VA, AIAA Press, 1999

Characteristics of photonic nanojets from two-layer dielectric hemisphere

NASA Astrophysics Data System (ADS)

Liu, Yunyue; Liu, Xianchao; Li, Ling; Chen, Weidong; Chen, Yan; Huang, Yuerong; Xie, Zhengwei

2017-10-01

Not Available Project supported by State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences; Sichuan Provincial Department of Education, China (Grant No. 16ZA0047); the State Key Laboratory of Metastable Materials Science and Technology, Yansan University, China (Grant No. 201509); and the Large Precision Instruments Open Project Foundation of Sichuan Normal University, China (Grant Nos. DJ2015-57, DJ2015-58, DJ2015-60, DJ2016-58, and DJ2016-59).

Computer Simulation Of An In-Process Surface Finish Sensor.

NASA Astrophysics Data System (ADS)

Rakels, Jan H.

1987-01-01

It is generally accepted, that optical methods are the most promising for the in-process measurement of surface finish. These methods have the advantages of being non-contacting and fast data acquisition. Furthermore, these optical instruments can be easily retrofitted on existing machine-tools. In the Micro-Engineering Centre at the University of Warwick, an optical sensor has been developed which can measure the rms roughness, slope and wavelength of turned and precision ground surfaces during machining. The operation of this device is based upon the Kirchhoff-Fresnel diffraction integral. Application of this theory to ideal turned and ground surfaces is straightforward, and indeed the calculated diffraction patterns are in close agreement with patterns produced by an actual optical instrument. Since it is mathematically difficult to introduce real machine-tool behaviour into the diffraction integral, a computer program has been devised, which simulates the operation of the optical sensor. The program produces a diffraction pattern as a graphical output. Comparison between computer generated and actual diffraction patterns of the same surfaces show a high correlation. The main aim of this program is to construct an atlas, which maps known machine-tool errors versus optical diffraction patterns. This atlas can then be used for machine-tool condition diagnostics. It has been found that optical monitoring is very sensitive to minor defects. Therefore machine-tool detoriation can be detected before it is detrimental.

The structure, energetics, and nature of the chemical bonding of phenylthiol adsorbed on the Au(111) surface: implications for density-functional calculations of molecular-electronic conduction.

PubMed

Bilić, Ante; Reimers, Jeffrey R; Hush, Noel S

2005-03-01

The adsorption of phenylthiol on the Au(111) surface is modeled using Perdew and Wang density-functional calculations. Both direct molecular physisorption and dissociative chemisorption via S-H bond cleavage are considered as well as dimerization to form disulfides. For the major observed product, the chemisorbed thiol, an extensive potential-energy surface is produced as a function of both the azimuthal orientation of the adsorbate and the linear translation of the adsorbate through the key fcc, hcp, bridge, and top binding sites. Key structures are characterized, the lowest-energy one being a broad minimum of tilted orientation ranging from the bridge structure halfway towards the fcc one. The vertically oriented threefold binding sites, often assumed to dominate molecular electronics measurements, are identified as transition states at low coverage but become favored in dense monolayers. A similar surface is also produced for chemisorption of phenylthiol on Ag(111); this displays significant qualitative differences, consistent with the qualitatively different observed structures for thiol chemisorption on Ag and Au. Full contours of the minimum potential energy as a function of sulfur translation over the crystal face are described, from which the barrier to diffusion is deduced to be 5.8 kcal mol(-1), indicating that the potential-energy surface has low corrugation. The calculated bond lengths, adsorbate charge and spin density, and the density of electronic states all indicate that, at all sulfur locations, the adsorbate can be regarded as a thiyl species that forms a net single covalent bond to the surface of strength 31 kcal mol(-1). No detectable thiolate character is predicted, however, contrary to experimental results for alkyl thiols that indicate up to 20%-30% thiolate involvement. This effect is attributed to the asymptotic-potential error of all modern density functionals that becomes manifest through a 3-4 eV error in the lineup of the adsorbate and substrate bands. Significant implications are described for density-functional calculations of through-molecule electron transport in molecular electronics.

Skeletal Muscle Differentiation on a Chip Shows Human Donor Mesoangioblasts' Efficiency in Restoring Dystrophin in a Duchenne Muscular Dystrophy Model.

PubMed

Serena, Elena; Zatti, Susi; Zoso, Alice; Lo Verso, Francesca; Tedesco, F Saverio; Cossu, Giulio; Elvassore, Nicola

2016-12-01

: Restoration of the protein dystrophin on muscle membrane is the goal of many research lines aimed at curing Duchenne muscular dystrophy (DMD). Results of ongoing preclinical and clinical trials suggest that partial restoration of dystrophin might be sufficient to significantly reduce muscle damage. Different myogenic progenitors are candidates for cell therapy of muscular dystrophies, but only satellite cells and pericytes have already entered clinical experimentation. This study aimed to provide in vitro quantitative evidence of the ability of mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes derived from DMD patients, using a microengineered model. We designed an ad hoc experimental strategy to miniaturize on a chip the standard process of muscle regeneration independent of variables such as inflammation and fibrosis. It is based on the coculture, at different ratios, of human dystrophin-positive myogenic progenitors and dystrophin-negative myoblasts in a substrate with muscle-like physiological stiffness and cell micropatterns. Results showed that both healthy myoblasts and mesoangioblasts restored dystrophin expression in DMD myotubes. However, mesoangioblasts showed unexpected efficiency with respect to myoblasts in dystrophin production in terms of the amount of protein produced (40% vs. 15%) and length of the dystrophin membrane domain (210-240 µm vs. 40-70 µm). These results show that our microscaled in vitro model of human DMD skeletal muscle validated previous in vivo preclinical work and may be used to predict efficacy of new methods aimed at enhancing dystrophin accumulation and distribution before they are tested in vivo, reducing time, costs, and variability of clinical experimentation. This study aimed to provide in vitro quantitative evidence of the ability of human mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes derived from patients with Duchenne muscular dystrophy (DMD), using a microengineered model. An ad hoc experimental strategy was designed to miniaturize on a chip the standard process of muscle regeneration independent of variables such as inflammation and fibrosis. This microscaled in vitro model, which validated previous in vivo preclinical work, revealed that mesoangioblasts showed unexpected efficiency as compared with myoblasts in dystrophin production. Consequently, this model may be used to predict efficacy of new drugs or therapies aimed at enhancing dystrophin accumulation and distribution before they are tested in vivo. ©AlphaMed Press.

Enhanced adsorption of Ca-ATPase containing vesicles on a negatively charged solid-supported-membrane for the investigation of membrane transporters.

PubMed

Sacconi, Alessio; Moncelli, Maria Rosa; Margheri, Giancarlo; Tadini-Buoninsegni, Francesco

2013-11-12

A convenient model system for a biological membrane is a solid-supported membrane (SSM), which consists of a gold-supported alkanethiol|phospholipid bilayer. In combination with a concentration jump method, SSMs have been used for the investigation of several membrane transporters. Vesicles incorporating sarcoplasmic reticulum Ca-ATPase (SERCA) were adsorbed on a negatively charged SSM (octadecanethiol|phosphatidylserine bilayer). The current signal generated by the adsorbed vesicles following an ATP concentration jump was compared to that produced by SERCA-containing vesicles adsorbed on a conventional SSM (octadecanethiol|phosphatidylcholine bilayer). A significantly higher current amplitude was recorded on the serine-based SSM. The adsorption of SERCA-incorporating vesicles on the SSM was then characterized by surface plasmon resonance (SPR). The SPR measurements clearly indicate that in the presence of Ca(2+) and Mg(2+), the amount of adsorbed vesicles on the serine-based SSM is about twice that obtained using the conventional SSM, thereby demonstrating that the higher current amplitude recorded on the negatively charged SSM is correlated with a greater quantity of adsorbed vesicles. The enhanced adsorption of membrane vesicles on the PS-based SSM may be useful to study membrane preparations with a low concentration of transport protein generating small current signals, as in the case of various recombinantly expressed proteins.

Site-dependent atomic and molecular affinities of hydrocarbons, amines and thiols on diamond nanoparticles

NASA Astrophysics Data System (ADS)

Lai, Lin; Barnard, Amanda S.

2016-04-01

Like many of the useful nanomaterials being produced on the industrial scale, the surface of diamond nanoparticles includes a complicated mixture of various atomic and molecular adsorbates, attaching to the facets following synthesis. Some of these adsorbates may be functional, and adsorption is encouraged to promote applications in biotechnology and nanomedicine, but others are purely adventurous and must be removed prior to use. In order to devise more effective treatments it is advantageous to know the relative strength of the interactions of the adsorbates with the surface, and ideally how abundant they are likely to be under different conditions. In this paper we use a series of explicit electronic structure simulations to map the distribution of small hydrocarbons, amines and thiols on a 2.9 nm diamond nanoparticle, with atomic level resolution, in 3-D. We find a clear relationship between surface reconstructions, facet orientation, and the distribution of the different adsorbates; with a greater concentration expected on the (100) and (110) facets, particularly when the supersaturation in the reservoir is high. Adsorption on the (111) facets is highly unlikely, suggesting that controlled graphitization may be a useful stage in the cleaning and treatment of nanodiamonds, prior to the deliberate coating with functional adsorbates needed for drug delivery applications.

Innovative Elution Processes for Recovering Uranium and Transition Metals from Amidoxime-based Adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wai, Chien M.

Amidoxime-based polymer fibers are considered one of the most promising materials for sequestering uranium from seawater. The high-surface-area polymer fibers containing amidoxime and carboxylate groups synthesized by Oak Ridge National Lab (ORNL-AF1) show very high uranium adsorption capacities known in the literature. Effective elution of uranium and repeated use of the adsorbent are important factors affecting the cost of producing uranium from seawater using this material. Traditional acid leaching of uranium followed by KOH conditioning of the fiber causes chemical changes and physical damage to the ORNL-AF1 adsorbent. Two alkaline solution leaching methods were developed by this project, one usesmore » a highly concentrated (3 M) potassium bicarbonate solution at pH 8.3 and 40 °C; the other uses a mixture of sodium carbonate and hydrogen peroxide at pH 10.4. Both elution methods do not require KOH conditioning prior to reusing the fiber adsorbent. The conditions of eluting uranium from the amidoxime-based adsorbent using these alkaline solutions are confirmed by thermodynamic calculations. The bicarbonate elution method is selective for uranium recovery compared to other elution methods and causes no chemical change to the fiber material based on FTIR spectroscopy« less

Solid waste from leather industry as adsorbent of organic dyes in aqueous-medium.

PubMed

Oliveira, Luiz C A; Gonçalves, Maraísa; Oliveira, Diana Q L; Guerreiro, Mário C; Guilherme, Luiz R G; Dallago, Rogério M

2007-03-06

The industrial tanning of leather usually produces considerable amounts of chromium-containing solid waste and liquid effluents and raises many concerns on its environmental effect as well as on escalating landfill costs. Actually, these shortcomings are becoming increasingly a limiting factor to this industrial activity that claims for alternative methods of residue disposals. In this work, it is proposed a novel alternative destination of the solid waste, based on the removal of organic contaminants from the out coming aqueous-residue. The adsorption isotherm pattern for the wet blue leather from the Aurea tanning industry in Erechim-RS (Brazil) showed that these materials present high activity on adsorbing the reactive red textile dye as well as other compounds. The adsorbent materials were characterized by IR spectroscopy and SEM and tested for the dye adsorption (reactive textile and methylene blue dyes). The concentrations of dyes were measured by UV-vis spectrophotometry and the chromium extraction from leather waste was realized by basic hydrolysis and determined by atomic absorption. As a low cost abundant adsorbent material with high adsorption ability on removing dye methylene blue (80mgg(-1)) and textile dye reactive red (163mgg(-1)), the leather waste is revealed to be a interesting alternative relatively to more costly adsorbent materials.

Structure and adsorption properties of a porous cooper hexacyanoferrate polymorph

NASA Astrophysics Data System (ADS)

Roque-Malherbe, R.; Carballo, E.; Polanco, R.; Lugo, F.; Lozano, C.

2015-11-01

The key questions addressed here were: the structure elucidation and the investigation of the adsorption space and framework expansion effect of a Cu(II) hexacyanoferrate (III) polymorph (labeled Cu-PBA-I). The structural analysis was performed with a broad set of characterization methods. Additionally, a low and high pressure carbon dioxide adsorption investigation was performed, assuming, to comprehend the adsorption experiments, that the adsorbent plus the adsorbed phase were a solid solution. We concluded: that the Cu-PBA-I presented the following composition, K1/4 Cu (II)[ Fe (III)(CN)6 ] 3 / 4⋄1/4 nH2 O , exhibited an antiferromagnetic behavior and displayed a thermally stable I 4 bar m 2 space group lattice in the degassed state. Moreover, the low pressure adsorption study allowed the calculation of the micropore volume, W=0.09 cm3/g and the isosteric heat of adsorption, qiso=19 kJ/mol; further, the high pressure adsorption data revealed an extremely high adsorption capacity owing to a framework expansion effect. Finally, the DRIFTS spectrum of adsorbed CO2 displayed peaks corresponding to carbon dioxide physically adsorbed and interacting with electron accepting Lewis acid sites. Hence, was produced an excellent adsorbent which combine porosity and anti-ferromagnetism, antagonist properties rarely found together.

Carbonised jackfruit peel as an adsorbent for the removal of Cd(II) from aqueous solution.

PubMed

Inbaraj, B Stephen; Sulochana, N

2004-08-01

The fruit of the jack (Artocarpus heterophyllus) is one of the popular fruits in India, where the total area under this fruit is about 13,460 ha. A significant amount of peel (approximately 2,714-11,800 kg per tree per year) is discarded as agricultural waste, as apart from its use as a table fruit, it is popular in many culinary preparations. Treatment of jackfruit peel with sulphuric acid produced a carbonaceous product which was used to study its efficiency as an adsorbent for the removal of Cd(II) from aqueous solution. Batch experiments were performed as a function of process parameters; agitation time, initial metal concentration, adsorbent concentration and pH. Kinetic analyses made with Lagergren pseudo-first-order, Ritchie second-order and modified Ritchie second-order models showed better fits with modified Ritchie second-order model. The Langmuir-Freundlich (Sips equation) model best defined the experimental equilibrium data among the three isotherm models (Freundlich, Langmuir and Langmuir-Freundlich) tested. Taking a particular metal concentration, the optimum dose and pH required for the maximum metal removal was established. A complete recovery of the adsorbed metal ions from the spent adsorbent was achieved by using 0.01 M HCl.

CHITOSAN-CELLULOSE COMPOSITE MATERIALS: PREPARATION, CHARACTERIZATION AND APPLICATION FOR REMOVAL OF MICROCYSTIN

PubMed Central

Tran, Chieu D.; Duri, Simon; Delneri, Ambra; Franko, Mladen

2013-01-01

We developed a simple and one-step method to prepare biocompatible composites from cellulose (CEL) and chitosan (CS). [BMIm+Cl−], an ionic liquid (IL), was used as a green solvent to dissolve and prepare the [CEL+CS] composites. Since majority (>88%) of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS], the method is recyclable. XRD, FTIR, NIR, 13C CP-MAS-NMR and SEM were used to monitor the dissolution and to characterize the composites. The composite was found to have combined advantages of their components: superior mechanical strength (from CEL) and excellent adsorption capability for microcystin-LR, a deadly toxin produced by cyanobacteria (from CS). Specifically, the mechanical strength of the composites increased with CEL loading; e.g., up to 5X increase in tensile strength was achieved by adding 80% of CEL into CS. Kinetic results of adsorption confirm that unique properties of CS remain intact in the composite, i.e., it is not only a very good adsorbent for microcystin but also is better than all other available adsorbents. For example, it can adsorb 4X times more microcystin than the best reported adsorbent. Importantly, the microcystin adsorbed can be quantitatively desorbed to enable the composite to be reused with similar adsorption efficiency. PMID:23542326

Treatment with activated carbon and other adsorbents as an effective method for the removal of volatile compounds in agricultural distillates.

PubMed

Balcerek, Maria; Pielech-Przybylska, Katarzyna; Patelski, Piotr; Dziekońska-Kubczak, Urszula; Jusel, Tomaš

2017-05-01

This study investigates the effect of treatment with activated carbon and other adsorbents on the chemical composition and organoleptics of a barley malt-based agricultural distillate. Contact with activated carbon is one of the methods by which the quality of raw distillates and spirit beverages can be improved. Samples placed in contact with 1 g activated carbon (SpiritFerm) per 100 ml distillate with ethanol content of 50% v/v for 1 h showed the largest reductions in the concentrations of most volatile compounds (aldehydes, alcohols, esters). Increasing the dose of adsorbent to over 1 g 100 ml -1 did not improve the purity of the agricultural distillate significantly. Of the tested compounds, acetaldehyde and methanol showed the lowest adsorption on activated carbon. The lowest concentrations of these congeners (expressed in mg l -1 alcohol 100% v/v) were measured in solutions with ethanol contents of 70-80% v/v, while solutions with an alcoholic strength by volume of 40% did not show statistically significant decreases in these compounds in relation the control sample. The reductions in volatile compounds were compared with those for other adsorbents based on silica or activated carbon and silica. An interesting alternative to activated carbon was found to be an adsorbent prepared from activated carbon and silica (Spiricol). Treatment with this adsorbent produced distillate with the lowest concentrations of acetaldehyde and isovaleraldehyde, and led to the greatest improvement in its organoleptics.

Valorization of solid waste products from olive oil industry as potential adsorbents for water pollution control--a review.

PubMed

Bhatnagar, Amit; Kaczala, Fabio; Hogland, William; Marques, Marcia; Paraskeva, Christakis A; Papadakis, Vagelis G; Sillanpää, Mika

2014-01-01

The global olive oil production for 2010 is estimated to be 2,881,500 metric tons. The European Union countries produce 78.5% of the total olive oil, which stands for an average production of 2,136,000 tons. The worldwide consumption of olive oil increased of 78% between 1990 and 2010. The increase in olive oil production implies a proportional increase in olive mill wastes. As a consequence of such increasing trend, olive mills are facing severe environmental problems due to lack of feasible and/or cost-effective solutions to olive-mill waste management. Therefore, immediate attention is required to find a proper way of management to deal with olive mill waste materials in order to minimize environmental pollution and associated health risks. One of the interesting uses of solid wastes generated from olive mills is to convert them as inexpensive adsorbents for water pollution control. In this review paper, an extensive list of adsorbents (prepared by utilizing different types of olive mill solid waste materials) from vast literature has been compiled, and their adsorption capacities for various aquatic pollutants removal are presented. Different physicochemical methods that have been used to convert olive mill solid wastes into efficient adsorbents have also been discussed. Characterization of olive-based adsorbents and adsorption mechanisms of various aquatic pollutants on these developed olive-based adsorbents have also been discussed in detail. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.

Influence of Epicuticular Physicochemical Properties on Porcine Rotavirus Adsorption to 24 Leafy Green Vegetables and Tomatoes

PubMed Central

Palma-Salgado, Sindy Paola; Storm, Andrew Page; Feng, Hao; Juvik, John A.; Nguyen, Thanh H.

2015-01-01

Foodborne diseases are a persistent problem in the United States and worldwide. Fresh produce, especially those used as raw foods like salad vegetables, can be contaminated, causing illness. In this study, we determined the number of rotaviruses adsorbed on produce surfaces using group A porcine rotaviruses and 24 cultivars of leafy vegetables and tomato fruits. We also characterized the physicochemical properties of each produce’s outermost surface layer, known as the epicuticle. The number of rotaviruses found on produce surfaces varied among cultivars. Three-dimensional crystalline wax structures on the epicuticular surfaces were found to significantly contribute to the inhibition of viral adsorption to the produce surfaces (p = 0.01). We found significant negative correlations between the number of rotaviruses adsorbed on the epicuticular surfaces and the concentrations of alkanes, fatty acids, and total waxes on the epicuticular surfaces. Partial least square model fitting results suggest that alkanes, ketones, fatty acids, alcohols, contact angle and surface roughness together can explain 60% of the variation in viral adsorption. The results suggest that various fresh produce surface properties need to be collectively considered for efficient sanitation treatments. Up to 10.8% of the originally applied rotaviruses were found on the produce surfaces after three washing treatments, suggesting a potential public health concern regarding rotavirus contamination. PMID:26181904

The uranium from seawater program at PNNL: Overview of marine testing, adsorbent characterization, adsorbent durability, adsorbent toxicity, and deployment studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Gary A.; Kuo, Li -Jung; Janke, Christopher James

The Pacific Northwest National Laboratory's (PNNL) Marine Science Laboratory (MSL) located along the coast of Washington State is evaluating the performance of uranium adsorption materials being developed for seawater extraction under realistic marine conditions with natural seawater. Two types of exposure systems were employed in this program: flow-through columns for testing of fixed beds of individual fibers and pellets and a recirculating water flume for testing of braided adsorbent material. Testing consists of measurements of the adsorption of uranium and other elements from seawater as a function of time, typically 42 to 56 day exposures, to determine the adsorbent capacitymore » and adsorption rate (kinetics). Analysis of uranium and other trace elements collected by the adsorbents was conducted following strong acid digestion of the adsorbent with 50% aqua regia using either Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The ORNL 38H adsorbent had a 56 day adsorption capacity of 3.30 ± 0.68 g U/ kg adsorbent (normalized to a salinity of 35 psu), a saturation adsorption capacity of 4.89 ± 0.83 g U/kg of adsorbent material (normalized to a salinity of 35 psu) and a half-saturation time of 28 10 days. The AF1 adsorbent material had a 56 day adsorption capacity of 3.9 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu), a saturation capacity of 5.4 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu) and a half saturation time of 23 2 days. The ORNL amidoxime-based adsorbent materials are not specific for uranium, but also adsorb other elements from seawater. The major doubly charged cations in seawater (Ca and Mg) account for a majority of the cations adsorbed (61% by mass and 74% by molar percent). For the ORNL AF1 adsorbent material, U is the 4th most abundant element adsorbed by mass and 7th most abundant by molar percentage. Marine testing at Woods Hole Oceanographic Institution with the ORNL AF1 adsorbent produced 15% and 55% higher adsorption capacities than observed at PNNL for column and flume testing, respectively. Variations in competing ions may be the explanation for the regional differences. In addition to marine testing, a number of other efforts are underway to characterize adsorbents and impacts of deployment on the marine environment. Highlights include: Hydrodynamic modelling predicts that a farm of adsorbent materials will likely have minimal effect on ocean currents and removal of uranium and other elements from seawater when densities are < 1800 braids/km 2. A decrease in U adsorption capacity of up to 30% was observed after 42 days of exposure due to biofouling when the ORNL braided adsorbent AI8 was exposed to raw seawater in a flume in the presence of light. An identical raw seawater exposure with no light exposure showed little or no impact to adsorption capacity from biofouling. No toxicity was observed with column effluents of any absorbent materials tested to date. Toxicity could be induced with some non amidoxime-based absorbents only when the ratio of solid absorbent to test media was increased to highly unrealistic levels. Thermodynamic modeling of the seawater-amidoxime adsorbent was performed using the geochemical modeling program PHREEQC. Modeling of the binding of Ca, Mg, Fe, Ni, Cu, U, and V from batch interactions with seawater across a variety of concentrations of the amidoxime binding group reveal that when binding sites are limited (1 x 10 -8 binding sites/kg seawater), vanadium heavily out-competes other ions for the amidoxime sites. In contrast, when binding sites are abundant magnesium and calcium dominate the total percentage of metals bound to the sorbent.« less

The uranium from seawater program at PNNL: Overview of marine testing, adsorbent characterization, adsorbent durability, adsorbent toxicity, and deployment studies

DOE PAGES

Gill, Gary A.; Kuo, Li -Jung; Janke, Christopher James; ...

2016-02-07

The Pacific Northwest National Laboratory's (PNNL) Marine Science Laboratory (MSL) located along the coast of Washington State is evaluating the performance of uranium adsorption materials being developed for seawater extraction under realistic marine conditions with natural seawater. Two types of exposure systems were employed in this program: flow-through columns for testing of fixed beds of individual fibers and pellets and a recirculating water flume for testing of braided adsorbent material. Testing consists of measurements of the adsorption of uranium and other elements from seawater as a function of time, typically 42 to 56 day exposures, to determine the adsorbent capacitymore » and adsorption rate (kinetics). Analysis of uranium and other trace elements collected by the adsorbents was conducted following strong acid digestion of the adsorbent with 50% aqua regia using either Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The ORNL 38H adsorbent had a 56 day adsorption capacity of 3.30 ± 0.68 g U/ kg adsorbent (normalized to a salinity of 35 psu), a saturation adsorption capacity of 4.89 ± 0.83 g U/kg of adsorbent material (normalized to a salinity of 35 psu) and a half-saturation time of 28 10 days. The AF1 adsorbent material had a 56 day adsorption capacity of 3.9 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu), a saturation capacity of 5.4 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu) and a half saturation time of 23 2 days. The ORNL amidoxime-based adsorbent materials are not specific for uranium, but also adsorb other elements from seawater. The major doubly charged cations in seawater (Ca and Mg) account for a majority of the cations adsorbed (61% by mass and 74% by molar percent). For the ORNL AF1 adsorbent material, U is the 4th most abundant element adsorbed by mass and 7th most abundant by molar percentage. Marine testing at Woods Hole Oceanographic Institution with the ORNL AF1 adsorbent produced 15% and 55% higher adsorption capacities than observed at PNNL for column and flume testing, respectively. Variations in competing ions may be the explanation for the regional differences. In addition to marine testing, a number of other efforts are underway to characterize adsorbents and impacts of deployment on the marine environment. Highlights include: Hydrodynamic modelling predicts that a farm of adsorbent materials will likely have minimal effect on ocean currents and removal of uranium and other elements from seawater when densities are < 1800 braids/km 2. A decrease in U adsorption capacity of up to 30% was observed after 42 days of exposure due to biofouling when the ORNL braided adsorbent AI8 was exposed to raw seawater in a flume in the presence of light. An identical raw seawater exposure with no light exposure showed little or no impact to adsorption capacity from biofouling. No toxicity was observed with column effluents of any absorbent materials tested to date. Toxicity could be induced with some non amidoxime-based absorbents only when the ratio of solid absorbent to test media was increased to highly unrealistic levels. Thermodynamic modeling of the seawater-amidoxime adsorbent was performed using the geochemical modeling program PHREEQC. Modeling of the binding of Ca, Mg, Fe, Ni, Cu, U, and V from batch interactions with seawater across a variety of concentrations of the amidoxime binding group reveal that when binding sites are limited (1 x 10 -8 binding sites/kg seawater), vanadium heavily out-competes other ions for the amidoxime sites. In contrast, when binding sites are abundant magnesium and calcium dominate the total percentage of metals bound to the sorbent.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee

Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfillmore » gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.« less

The addition of zeolite adsorbents and calcium oxide on purification of bioethanol from sugar palm (arenga pinnata merr)

NASA Astrophysics Data System (ADS)

Herlina, Netti; Siska Dewi Harahap, Ici

2018-03-01

Bioethanol (C2H5OH) is a biochemical liquid produced by microorganisms through fermentation process on sugar molecules from carbohydrates. Bioethanol is a fuel of vegetable oil that has similar properties to premium. With its main product of palm juice, Sugar palm (Arenga pinnata) is a potential source of sugar and carbohydrate for bioethanol production. Production of palm juice can reach up to 12-14 liters/tree/day with total sugar content in palm juice ranges from 12-15%. The purpose of this research was to produce highly-concentrated bioethanol from palm juice through fermentation proccess to subtitude fossil fuel. This study was conducted with three stages of treatment, namely: the fermentation of palm juice, distillation of bioethanol, and purification of bioethanol with the addition of adsorbent zeolite and calcium oxide.

Metabolic Heat Regenerated Temperature Swing Adsorption for CO(sub 2) and Heat Removal/Rejection in a Martian PLSS

NASA Technical Reports Server (NTRS)

Iacomini, Christine; Powers, Aaron; Bowers, Chad; Straub-Lopez, Katie; Anderson, Grant; MacCallum, Taber; Paul, Heather

2007-01-01

Two of the fundamental problems facing the development of a Portable Life Support System (PLSS) for use on Mars, are (i) heat rejection (because traditional technologies use sublimation of water, which wastes a scarce resource and contaminates the premises), and (ii) rejection of CO2 in an environment with a ppCO2 of 0.4-0.9 kPa. Patent-pending Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed to address both these challenges. The technology utilizes an adsorbent that when cooled with liquid CO2 to near sublimation temperatures (195K) removes metabolically-produced CO2 in the vent loop. Once fully loaded, the adsorbent is then warmed externally by the vent loop (approx. 300K), rejecting the captured CO2 to Mars ambient. Two beds are used to effect a continuous cycle of CO2 removal/rejection as well as facilitate heat exchange out of the vent loop. Any cryogenic fluid can be used in the application; however, since CO2 is readily available at Mars and can be easily produced and stored on the Martian surface, the solution is rather elegant and less complicated when employing liquid CO2. As some metabolic heat will need to be rejected anyway, finding a practical use for metabolic heat is also an overall benefit to the PLSS. To investigate the feasibility of the technology, a series of experiments was conducted which lead to the selection and partial characterization of an appropriate adsorbent. The adsorbent NaX successfully removed CO2 from a simulated vent loop at the prescribed temperature swing anticipated during PLSS operating conditions on Mars using a cryogenic fluid. Thermal conductivity of the adsorbent was also measured to eventually aid in a demonstrator design of the technology. These results provide no show stoppers to the development of MTSA technology and allow its development to focus on other design challenges as listed in the conclusions.

Effects of solution chemistry on the sunlight inactivation of particles-associated viruses MS2.

PubMed

Wu, Xueyin; Feng, Zhe; Yuan, Baoling; Zhou, Zhenming; Li, Fei; Sun, Wenjie

2018-02-01

The inactivation efficacy of bacteriophage MS2 by simulated sunlight irradiation was investigated to understand the effects of MS2 aggregation and adsorption to particles in solutions with different components. Kaolinite and Microcystis aeruginosa were used as model inorganic and organic particles, respectively. Lower pH and di-valent ions (Ca 2+ ) were main factors on the aggregation and inactivation of MS2. In the presence of both particles, there was no significant impact on the MS2 inactivation efficacy by kaolinite (10-200mM) or Microcystis aeruginosa (10 2 -10 5 Cells/mL) in 1mM NaCl at pH 7. However at lower pH 3, MS2 aggregates formed in the particle-free and kaolinite-containing solutions, caused lower inactivation since the outer viruses of aggregation protect the inner viruses. In addition, more MS2 adsorbed on Microcystis aeruginosa at lower pH (3 and 4). Microcystis aeruginosa would act as a potential photosensitizer for ROS production to inactivate the adsorbed MS2, since extracellular organic matter (EOM) of Microcystis aeruginosa was detected in this study, which has been reported to produce ROS under solar irradiation. At pH 7, Na + had no effect on the inactivation of MS2, because MS2 was stable and dispersed even at 200mM Na + . MS2 aggregated and adsorbed on particles even at 10mM Ca 2+ and led to lower inactivation. Kaolinite cannot offer enough protection to adsorbed MS2 as aggregation and Microcystis aeruginosa acts as potential photosensitizer to produce ROS and inactivate the adsorbed MS2 at high concentration of Ca 2+ . In particle-free solution, SRNOM inhibited MS2 inactivation by shielding the sunlight and coating MS2 to increase its survival. Copyright © 2017 Elsevier B.V. All rights reserved.

Micromotor-based lab-on-chip immunoassays.

PubMed

García, Miguel; Orozco, Jahir; Guix, Maria; Gao, Wei; Sattayasamitsathit, Sirilak; Escarpa, Alberto; Merkoçi, Arben; Wang, Joseph

2013-02-21

Here we describe the first example of using self-propelled antibody-functionalized synthetic catalytic microengines for capturing and transporting target proteins between the different reservoirs of a lab-on-a-chip (LOC) device. A new catalytic polymer/Ni/Pt microtube engine, containing carboxy moieties on its mixed poly(3,4-ethylenedioxythiophene) (PEDOT)/COOH-PEDOT polymeric outermost layer, is further functionalized with the antibody receptor to selectively recognize and capture the target protein. The new motor-based microchip immunoassay operations are carried out without any bulk fluid flow, replacing the common washing steps in antibody-based protein bioassays with the active transport of the captured protein throughout the different reservoirs, where each step of the immunoassay takes place. A first microchip format involving an 'on-the-fly' double-antibody sandwich assay (DASA) is used for demonstrating the selective capture of the target protein, in the presence of excess of non-target proteins. A secondary antibody tagged with a polymeric-sphere tracer allows the direct visualization of the binding events. In a second approach the immuno-nanomotor captures and transports the microsphere-tagged antigen through a microchannel network. An anti-protein-A modified microengine is finally used to demonstrate the selective capture, transport and convenient label-free optical detection of a Staphylococcus aureus target bacteria (containing proteinA in its cell wall) in the presence of a large excess of non-target (Saccharomyces cerevisiae) cells. The resulting nanomotor-based microchip immunoassay offers considerable potential for diverse applications in clinical diagnostics, environmental and security monitoring fields.

Surface-Bound Intermediates in Low-Temperature Methanol Synthesis on Copper. Participants and Spectators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yong; Mei, Donghai; Peden, Charles H.F.

The reactivity of surface adsorbed species present on copper catalysts during methanol synthesis at low temperatures was studied by simultaneous infrared spectroscopy (IR) and mass spectroscopy (MS) measurements during “titration” (transient surface reaction) experiments with isotopic tracing. The results show that adsorbed formate is a major bystander species present on the surface under steady-state methanol synthesis reaction conditions, but it cannot be converted to methanol by reaction with pure H 2, nor with H 2 plus added water. Formate-containing surface adlayers for these experiments were produced during steady state catalysis in (a) H 2:CO 2 (with substantial formate coverage) andmore » (b) moist H 2:CO (with no IR visible formate species). Both these reaction conditions produce methanol at steady state with relatively high rates. Adlayers containing formate were also produced by (c) formic acid adsorption. Various "titration" gases were used to probe these adlayers at modest temperatures (T = 410-450K) and 6 bar total pressure. Methanol gas (up to ~1% monolayer equivalent) was produced in "titration" from the H 2:CO 2 catalytic adlayers by H 2 plus water, but not by dry hydrogen. The decay in the formate IR features accelerated in the presence of added water vapor. The H 2:CO:H 2O catalytic adlayer produced similar methanol titration yields in H 2 plus water but showed no surface formate features in IR (less than 0.2% monolayer coverage). Finally, formate from formic acid chemisorption produced no methanol under any titration conditions. Even under (H 2:CO 2) catalytic reaction conditions, isotope tracing showed that pre-adsorbed formate from formic acid did not contribute to the methanol produced. Although non-formate intermediates exist during low temperature methanol synthesis on copper which can be converted to methanol gas by titration with pure H 2 plus water in sufficient quantities for that intermediate to be observable by IR, formate itself is only a "spectator" in this reaction and gives no observable methanol upon any titration we performed with H 2 or H 2 plus water.« less

Novel method to reduce fishy aftertaste in wine and seafood pairing using alcohol-treated yeast cells.

PubMed

Tsuji, Toshikazu; Kanai, Keiko; Yokoyama, Aki; Tamura, Takayuki; Hanamure, Kenichi; Sasaki, Kanako; Takata, Ryoji; Yoshida, Satoshi

2012-06-20

"Fishy aftertaste" is sometimes perceived in wine consumed with seafood. Iron in wine has been reported to be a key compound that produces fishy aftertaste. However, cost-effective methods to remove iron from wine have not been developed. Here, we describe a cost-effective and safe iron adsorbent consisting of alcohol-treated yeast (ATY) cells based on the observation that nonviable cells adsorbed iron after completion of fermentation. Treatment of cells with more than 40% (v/v) ethanol killed them without compromising their ability to adsorb iron. Drying the ATY cells did not reduce iron adsorption. Use of ATY cells together with phytic acid had a synergistic effect on iron removal. We term this means of removing iron the "ATY-PA" method. Sensory analysis indicated that fishy aftertaste in wine-seafood pairings was not perceived if the wine had been pretreated with both ATY cells and phytic acid.

Comparison of hydrogen and deuterium adsorption on Pd(100).

PubMed

Gladys, M J; Kambali, I; Karolewski, M A; Soon, A; Stampfl, C; O'Connor, D J

2010-01-14

Low energy ion recoil spectroscopy is a powerful technique for the determination of adsorbate position on metal surfaces. In this study, this technique is employed to compare the adsorption sites of hydrogen and deuterium on Pd(100) by detection of either H or D recoil ions produced by Ne(+) bombardment. Comparisons of experimental and Kalypso simulated azimuthal yield distributions show that, at room temperature, both hydrogen isotopes are adsorbed in the fourfold hollow site of Pd(100), however, at different heights above the surface (H-0.20 A and D-0.25 A). The adsorbates remain in the hollow site at all temperatures up to 383 K even though they move up to 0.40-0.45 A above the surface. Density functional theory calculations show a similar coverage dependent adsorption height for both H and D and confirm a real difference between the H and D adsorption heights based on zero point energies.

Intramolecular bonds resolved on a semiconductor surface

NASA Astrophysics Data System (ADS)

Sweetman, Adam; Jarvis, Samuel P.; Rahe, Philipp; Champness, Neil R.; Kantorovich, Lev; Moriarty, Philip

2014-10-01

Noncontact atomic force microscopy (NC-AFM) is now routinely capable of obtaining submolecular resolution, readily resolving the carbon backbone structure of planar organic molecules adsorbed on metal substrates. Here we show that the same resolution may also be obtained for molecules adsorbed on a reactive semiconducting substrate. Surprisingly, this resolution is routinely obtained without the need for deliberate tip functionalization. Intriguingly, we observe two chemically distinct apex types capable of submolecular imaging. We characterize our tip apices by "inverse imaging" of the silicon adatoms of the Si (111)-7×7 surface and support our findings with detailed density functional theory (DFT) calculations. We also show that intramolecular resolution on individual molecules may be readily obtained at 78 K, rather than solely at 5 K as previously demonstrated. Our results suggest a wide range of tips may be capable of producing intramolecular contrast for molecules adsorbed on semiconductor surfaces, leading to a much broader applicability for submolecular imaging protocols.

Uniform surface modification of diatomaceous earth with amorphous manganese oxide and its adsorption characteristics for lead ions

NASA Astrophysics Data System (ADS)

Li, Song; Li, Duanyang; Su, Fei; Ren, Yuping; Qin, Gaowu

2014-10-01

A novel method to produce composite sorbent material compromising porous diatomaceous earth (DE) and surface functionalized amorphous MnO2 is reported. Via a simple in situ redox reaction over the carbonized DE powders, a uniform layer of amorphous MnO2 was anchored onto the DE surface. The hybrid adsorbent was characterized by X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. The batch method has been employed to investigate the effects of surface coating on adsorption performance of DE. According to the equilibrium studies, the adsorption capacity of DE for adsorbing lead ions after MnO2 modification increased more than six times. And the adsorption of Pb2+ on the MnO2 surface is based on ion-exchange mechanism. The developed strategy presents a novel opportunity to prepare composite adsorbent materials by integrating nanocrystals with porous matrix.

Continuous hemoadsorption with a cytokine adsorber during sepsis - a review of the literature.

PubMed

Houschyar, Khosrow S; Pyles, Malcolm N; Rein, Susanne; Nietzschmann, Ina; Duscher, Dominik; Maan, Zeshaan N; Weissenberg, Kristian; Philipps, Hubertus M; Strauss, Catharina; Reichelt, Beate; Siemers, Frank

2017-05-29

Sepsis is a well-recognized healthcare issue worldwide, ultimately resulting in significant mortality, morbidity and resource utilization during and after critical illness. In its most severe form, sepsis causes multi-organ dysfunction that produces a state of critical illness characterized by severe immune dysfunction and catabolism. Sepsis induces the activation of complement factor via 3 pathways and the release of inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-1beta (IL-1β), resulting in a systemic inflammatory response. The inflammatory cytokines and nitric oxide release induced by sepsis decrease systemic vascular resistance, resulting in profound hypotension. The combination of hypotension and microvascular occlusion results in tissue ischemia and ultimately leads to multiple organ failure. Several clinical and experimental studies have reported that treatment using adsorption of cytokines is beneficial during endotoxemia and sepsis. This review article analyzes the efficacy of CytoSorb® adsorber in reducing the inflammatory response during sepsis. The CytoSorb® adsorber is known to have excellent adsorption rates for inflammatory cytokines such as IL-1β, IL-6, IL-8, IL-10, and TNF-α. Studies have demonstrated that treatment with cytokine adsorbing columns has beneficial effects on the survival rate and inflammatory responses in animal septic models. Additionally, several cases have been reported in which treatment with cytokine adsorbing columns is very effective in hemodynamic stabilization and in preventing organ failure in critically ill patients. Although further investigations and clinical trials are needed, treatment with cytokine adsorbing columns may play an important role in the treatment of sepsis in the near future.

Soluble hydrocarbons uptake by porous carbonaceous adsorbents at different water ionic strength and temperature: something to consider in oil spills.

PubMed

Flores-Chaparro, Carlos E; Ruiz, Luis Felipe Chazaro; Alfaro-De la Torre, Ma Catalina; Rangel-Mendez, Jose Rene

2016-06-01

Nowadays, petrochemical operations involve risks to the environment and one of the biggest is oil spills. Low molecular aromatics like benzene, toluene, and naphthalene dissolve in water, and because of their toxicological characteristics, these produce severe consequences to the environment. The oil spill cleanup strategies are mainly designed to deal with the heavy fractions accumulated on the water surface. Unfortunately, very limited information is available regarding the treatment of dissolved fractions.A commercial (Filtrasorb 400) and modified activated carbons were evaluated to remove benzene, toluene, and naphthalene from water, which are the most soluble aromatic hydrocarbons, at different ionic strengths (I) and temperatures (0-0.76 M and 4-25 °C, respectively). This allowed simulating the conditions of fresh and saline waters when assessing the performance of these adsorbents. It was found that the hydrocarbons adsorption affinity increased 12 % at a I of 0.5 M, due to the less negative charge of the adsorbent, while at a high I (≃0.76 M) in a synthetic seawater, the adsorption capacity decreased 21 % that was attributed to the adsorbent's pores occlusion by water clusters. Approximately, 40 h were needed to reach equilibrium; however, the maximum adsorption rate occurred within the first hour in all the cases. Moreover, the hydrocarbons adsorption and desorption capacities increased when the temperature augmented from 4 to 25 °C. On the other hand, thermally and chemically modified materials showed that the interactions between adsorbent-contaminant increased with the basification degree of the adsorbent surface.

Fruit stones from industrial waste for the removal of lead ions from polluted water.

PubMed

Rashed, M N

2006-08-01

Lead, one of the earliest metals recognized and used by humans, has a long history of beneficial use. However, it is now recognized as toxic and as posing a widespread threat to humans and wildlife. Treatment of lead from polluted water and wastewater has received a great deal of attention. Adsorption is one of the most common technologies for the treatment of lead-polluted water. This technique was evaluated here, with the goal of identifying innovative, low-cost adsorbent. This study presents experiments undertaken to determine the suitable conditions for the use of peach and apricot stones, produced from food industries as solid waste, as adsorbents for the removal of lead from aqueous solution. Chemical stability of adsorbents, effect of pH, adsorbents dose, adsorption time and equilibrium concentration were studied. The results reveal that adsorption of lead ions onto peach stone was stronger than onto apricot stone up to 3.36% at 3 h adsorption time. Suitable equilibrium time for the adsorption was 3-5 h (% Pb adsorption 93% for apricot and 97.64% for peach). The effective adsorption range for pH in the range was 7-8. Application of Langmuir and Freundlich isotherm models show high adsorption maximum and binding energies for using these adsorbents for the removal of lead ions from contaminated water and wastewater.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muth, Thomas R; Yamamoto, Yukinori; Frederick, David Alan

ORNL undertook an investigation using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate, to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas forming species. PM-titanium made from revert scrap where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders priormore » to consolidation. The removal / minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders, are critical to achieve equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.« less

Building vascular networks.

PubMed

Bae, Hojae; Puranik, Amey S; Gauvin, Robert; Edalat, Faramarz; Carrillo-Conde, Brenda; Peppas, Nicholas A; Khademhosseini, Ali

2012-11-14

Only a few engineered tissues-skin, cartilage, bladder-have achieved clinical success, and biomaterials designed to replace more complex organs are still far from commercial availability. This gap exists in part because biomaterials lack a vascular network to transfer the oxygen and nutrients necessary for survival and integration after transplantation. Thus, generation of a functional vasculature is essential to the clinical success of engineered tissue constructs and remains a key challenge for regenerative medicine. In this Perspective, we discuss recent advances in vascularization of biomaterials through the use of biochemical modification, exogenous cells, or microengineering technology.

Tuning group-velocity dispersion by optical force.

PubMed

Jiang, Wei C; Lin, Qiang

2013-07-15

We propose an optomechanical approach for dispersion dynamic tuning and microengineering by taking advantage of the optical force in nano-optomechanical structures. Simulations of a suspended coupled silicon waveguide show that the zero-dispersion wavelength can be tuned by 40 nm by an optical pump power of 3 mW. Our approach exhibits great potential for broad applications in dispersion-sensitive processes, which not only offers a new root toward versatile tunable nonlinear photonics but may also open up a great avenue toward a new regime of nonlinear dynamics coupling between nonlinear optical and optomechanical effects.

Microengineering of cellular interactions.

PubMed

Folch, A; Toner, M

2000-01-01

Tissue function is modulated by an intricate architecture of cells and biomolecules on a micrometer scale. Until now, in vitro cellular interactions were mainly studied by random seeding over homogeneous substrates. Although this strategy has led to important discoveries, it is clearly a nonoptimal analog of the in vivo scenario. With the incorporation--and adaptation--of microfabrication technology into biology, it is now possible to design surfaces that reproduce some of the aspects of that architecture. This article reviews past research on the engineering of cell-substrate, cell-cell, and cell-medium interactions on the micrometer scale.

Space micro-guidance and control - Applications and architectures

NASA Technical Reports Server (NTRS)

Mettler, Edward; Hadaegh, Fred Y.

1992-01-01

The features and the components of a new microscale guidance, navigation, and control (GN&C) system for future space systems are discussed. An approach is described for the utilization of new microengineering technologies for achieving major reductions in the GN&C system's mass, size, power, and costs. The micro-GN&C system and the component concepts include microactuated adaptive optics, micromachined inertial sensors, fiberoptic data nets with light-power transmission, and VLSI microcomputers. The GN&C system will be applied in microspacecraft, microlanders, microrovers, remote sensing platforms, interferometers, and deployable reflectors.

An improved design for AlGaN solar-blind avalanche photodiodes with enhanced avalanche ionization

NASA Astrophysics Data System (ADS)

Tang, Yin; Cai, Qing; Yang, Lian-Hong; Dong, Ke-Xiu; Chen, Dun-Jun; Lu, Hai; Zhang, Rong; Zheng, You-Dou

2017-03-01

Not Available Project supported by the State Key Project of Research and Development Plan, China (Grant No. 2016YFB0400903), the National Natural Science Foundation of China (Grant Nos. 61634002, 61274075, and 61474060), the Key Project of Jiangsu Province, China (Grant No. BE2016174), the Anhui University Natural Science Research Project, China (Grant No. KJ2015A153), the Open Fund (KFS) of State Key Lab of Optical Technologieson Nanofabrication and Microengineering, Institute of Optics and Electronics, Chinese Academy of Science.

Space micro-guidance and control - Applications and architectures

NASA Astrophysics Data System (ADS)

Mettler, Edward; Hadaegh, Fred Y.

1992-07-01

The features and the components of a new microscale guidance, navigation, and control (GN&C) system for future space systems are discussed. An approach is described for the utilization of new microengineering technologies for achieving major reductions in the GN&C system's mass, size, power, and costs. The micro-GN&C system and the component concepts include microactuated adaptive optics, micromachined inertial sensors, fiberoptic data nets with light-power transmission, and VLSI microcomputers. The GN&C system will be applied in microspacecraft, microlanders, microrovers, remote sensing platforms, interferometers, and deployable reflectors.

Optical fiber end-facet polymer suspended-mirror devices

NASA Astrophysics Data System (ADS)

Yao, Mian; Wu, Jushuai; Zhang, A. Ping; Tam, Hwa-Yaw; Wai, P. K. A.

2017-04-01

This paper presents a novel optical fiber device based on a polymer suspended mirror on the end facet of an optical fiber. With an own-developed optical 3D micro-printing technology, SU-8 suspended-mirror devices (SMDs) were successfully fabricated on the top of a standard single-mode optical fiber. Optical reflection spectra of the fabricated SU- 8 SMDs were measured and compared with theoretical analysis. The proposed technology paves a way towards 3D microengineering of the small end-facet of optical fibers to develop novel fiber-optic sensors.

Building Vascular Networks

PubMed Central

Bae, Hojae; Puranik, Amey S.; Gauvin, Robert; Edalat, Faramarz; Carrillo-Conde, Brenda; Peppas, Nicholas A.; Khademhosseini, Ali

2013-01-01

Only a few engineered tissues—skin, cartilage, bladder—have achieved clinical success, and biomaterials designed to replace more complex organs are still far from commercial availability. This gap exists in part because biomaterials lack a vascular network to transfer the oxygen and nutrients necessary for survival and integration after transplantation. Thus, generation of a functional vasculature is essential to the clinical success of engineered tissue constructs and remains a key challenge for regenerative medicine. In this Perspective, we discuss recent advances in vascularization of biomaterials through the use of biochemical modification, exogenous cells, or microengineering technology. PMID:23152325

Non-Invasive Monitoring for Optimization of Therapeutic Drug Delivery by Biodegradable Fiber to Prostate Tumor

DTIC Science & Technology

2008-02-01

v ol um e (c m ^3 ) Injection Internal pump External Pump Treatment starts Rat’s condition before treatment 0 0.2 0.4 0.6 0.8 1 550 650...of polysilicon thermal flexure actuator,” J. of Micromechanics and Microengineering.9, 2005. [36] A. Grayson, et.al., “Electronic MEMS for...36. [59] Q-H. Huang and N. K. S. Lee, “Analysis and design of polysilicon thermal flexure actuator,” J. Micromech. Microeng. 9 (1) pp. 64–70 (1999

Factors Affecting Pheromone Production by the Pepper Weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae) and Collection Efficiency

PubMed Central

Eller, Fred J.; Palmquist, Debra E.

2014-01-01

Several factors affecting pheromone production by male pepper weevils, Anthonomus eugenii Cano (Coleoptera: Curculionidae) as well as collection efficiency were investigated. Factors studied included: porous polymer adsorbents (Tenax versus Super Q), male age, time of day, male density, and male diet. Super Q was found to be a superior adsorbent for the male-produced alcohols and geranic acid as well as the plant-produced E-β-ocimene. Pheromone production increased with male age up to about age 15 days old and then tapered off. Male pepper weevils produced the highest amount of pheromone between noon and 2 pm (i.e., 4 to 6 h after “lights on”) and were producing ca. 800 ng/h during this period. Thereafter, pheromone production decreased and was extremely low during the scotophase (i.e., ca. 12 ng/h). Male pepper weevil density had a significant effect on both release rate and pheromone composition. Pheromone production on a per male basis was highest for individual males and the percentage of geranic acid in the blend was lowest for individual males. Male pepper weevils produced only extremely low amounts of pheromone when feeding on artificial diet; however, they produced very high amounts when on fresh peppers. Together, this information will be useful in designing better attractant lures for pepper weevils. PMID:26462948

Microwave pyrolysis with KOH/NaOH mixture activation: A new approach to produce micro-mesoporous activated carbon for textile dye adsorption.

PubMed

Liew, Rock Keey; Azwar, Elfina; Yek, Peter Nai Yuh; Lim, Xin Yi; Cheng, Chin Kui; Ng, Jo-Han; Jusoh, Ahmad; Lam, Wei Haur; Ibrahim, Mohd Danial; Ma, Nyuk Ling; Lam, Su Shiung

2018-06-19

A micro-mesoporous activated carbon (AC) was produced via an innovative approach combining microwave pyrolysis and chemical activation using NaOH/KOH mixture. The pyrolysis was examined over different chemical impregnation ratio, microwave power, microwave irradiation time and types of activating agents for the yield, chemical composition, and porous characteristic of the AC obtained. The AC was then tested for its feasibility as textile dye adsorbent. About 29 wt% yield of AC was obtained from the banana peel with low ash and moisture (<5 wt%), and showed a micro-mesoporous structure with high BET surface area (≤1038 m 2 /g) and pore volume (≤0.80 cm 3 /g), indicating that it can be utilized as adsorbent to remove dye. Up to 90% adsorption of malachite green dye was achieved by the AC. Our results indicate that the microwave-activation approach represents a promising attempt to produce good quality AC for dye adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impact of support calcination and competitive adsorbate in Fe/Mo-Al2O3 catalyst for synthesis of carbon nanotubes by V-flame

NASA Astrophysics Data System (ADS)

Sun, Ya-Ping; Sun, Bao-Min; Zhai, Gang; Guo, Yong-Hong; Jia, Xiao-Wei; Kang, Zhi-Zhong

2018-05-01

Carbon nanotubes (CNTs) were synthesized via carbon monoxide decomposition with aid of various Fe/Mo-Al2O3 catalysts by V-type flame method. The influences of support calcination and competitive adsorbates on the morphology and properties of CNTs were studied. SEM, HRTEM, TPO and Raman spectroscopy were applied to investigate the morphology and microstructure of CNT products. XRD, H2-TPR were employed to characterize catalysts. The obtained results indicate that calcinated support can increase production and promote the formation of CNTs with small diameter. Utilizing citric acid as a competitive adsorbate is successful in improving the quality of CNTs. Besides, the addition of citric acid and calcinated support in catalyst enhances the catalytic growth activity. The obtained CNTs have a diameter around 4–6 nm within a narrow diameter distribution range. Raman spectrum analysis also illustrates that highly graphitized CNTs are produced on the catalyst with calcinated support and citric acid. These results suggest that support calcination and competitive adsorbate have pronounced effect on the average diameter, diameter distribution, and graphitization of CNTs, which provides a simple and effective way to tune the properties of CNTs.

Adsorption of mercury by carbonaceous adsorbents prepared from rubber of tyre wastes.

PubMed

Manchón-Vizuete, E; Macías-García, A; Nadal Gisbert, A; Fernández-González, C; Gómez-Serrano, V

2005-03-17

Rubber from tyre wastes has been used to prepare carbonaceous adsorbents and the products obtained have been tested as adsorbents for mercury in aqueous solution. The adsorbents have been prepared by applying thermal, chemical and combined (thermal and chemical or vice versa) treatments. Tyre rubber has been: heated at 400 or 900 degrees C for 2 h in N2, chemically-treated with H2SO4, HNO3 or H2SO4/HNO3 solution for 24 h, and in two successive steps first heated at 400 degrees C for 2h in N2 and then treated with a H2SO4/HNO3 solution for 24 h, or vice versa. Resultant products have been characterised in terms of elementary composition and textural properties. The adsorption of mercury has been studied from kinetic and equilibrium standpoints. The treatments effected to tyre rubber decrease the carbon content and the hydrogen content. The oxygen content and the nitrogen content increase for the chemically-treated products. The heat treatment of tyre rubber results in a larger development of surface area, microporosity, and mesoporosity than the chemical treatments. These treatments, however, produce a great creation of macropores. In comparison to the starting rubber, the adsorption process of mercury is faster when the material is heated or treated with the H2SO4, HNO3 or 1:3 H2SO4/HNO3 solution. These adsorbents are either a non-porous solid or possess a high mesopore volume or a wide pore size distribution in the macropore range. The adsorption capacity is larger for products prepared by heat, chemical and combined treatments of the rubber. A common textural characteristic of these adsorbents is their better developed microporosity. The ability to adsorb mercury is higher for the heated products than for the chemically-treated ones. The maximum adsorption of mercury is 211 mg g(-1). The constant Kf of the Freundlich equation is as high as 108.9 mg g(-1).

Adsorption of selected endocrine disrupting compounds and pharmaceuticals on activated biochars.

PubMed

Jung, Chanil; Park, Junyeong; Lim, Kwang Hun; Park, Sunkyu; Heo, Jiyong; Her, Namguk; Oh, Jeill; Yun, Soyoung; Yoon, Yeomin

2013-12-15

Chemically activated biochar produced under oxygenated (O-biochar) and oxygen-free (N-biochar) conditions were characterized and the adsorption of endocrine disrupting compounds (EDCs): bisphenol A (BPA), atrazine (ATR), 17 α-ethinylestradiol (EE2), and pharmaceutical active compounds (PhACs); sulfamethoxazole (SMX), carbamazepine (CBM), diclofenac (DCF), ibuprofen (IBP) on both biochars and commercialized powdered activated carbon (PAC) were investigated. Characteristic analysis of adsorbents by solid-state nuclear magnetic resonance (NMR) was conducted to determine better understanding about the EDCs/PhACs adsorption. N-biochar consisted of higher polarity moieties with more alkyl (0-45 ppm), methoxyl (45-63 ppm), O-alkyl (63-108 ppm), and carboxyl carbon (165-187 ppm) content than other adsorbents, while aromaticity of O-biochar was higher than that of N-biochar. O-biochar was composed mostly of aromatic moieties, with low H/C and O/C ratios compared to the highly polarized N-biochar that contained diverse polar functional groups. The higher surface area and pore volume of N-biochar resulted in higher adsorption capacity toward EDCs/PhACs along with atomic-level molecular structural property than O-biochar and PAC. N-biochar had a highest adsorption capacity of all chemicals, suggesting that N-biochar derived from loblolly pine chip is a promising sorbent for agricultural and environmental applications. The adsorption of pH-sensitive dissociable SMX, DCF, IBP, and BPA varied and the order of adsorption capacity was correlated with the hydrophobicity (Kow) of adsorbates throughout the all adsorbents, whereas adsorption of non-ionizable CBM, ATR, and EE2 in varied pH allowed adsorbents to interact with hydrophobic property of adsorbates steadily throughout the study. Copyright © 2013 Elsevier B.V. All rights reserved.

Reactions of gas phase H atoms with ethylene, acetylene and ethane adsorbed on Ni( 1 1 1 )

NASA Astrophysics Data System (ADS)

Bürgi, T.; Trautman, T. R.; Gostein, M.; Lahr, D. L.; Haug, K. L.; Ceyer, S. T.

2002-03-01

The products of the reaction of the most energetic form of hydrogen, gas phase H atoms, with ethylene, acetylene and ethane adsorbed on a Ni(1 1 1) surface at 60 K are probed. Adsorbed ethylidyne (CCH 3) is identified by high resolution electron energy loss spectroscopy to be the major product (30% yield) in all three cases. Adsorbed acetylene is a minor product (3% yield) and arises as a consequence of a dynamic equilibrium between CCH 3 and C 2H 2 in the presence of gas phase H atoms. The observation of the same product for the reaction of H atoms with all three hydrocarbons implies that CCH 3 is the most stable C 2 species in the presence of coadsorbed hydrogen. The rates of CCH 3 production are measured as a function of the time of exposure of H atoms to each hydrocarbon. A simple kinetic model treating each reaction as a pseudo-first order reaction in the hydrocarbon coverage is fit to these data. A mechanism for the formation of CCH 3 via a CHCH 2 intermediate common to all three reactants is proposed to describe this model. The observed instability of the CH 2CH 3 species relative to C 2H 4 plays a role in the formulation of this mechanism as does the observed stability of CHCH 2 species in the presence of coadsorbed hydrogen. The CH 2CH 3 and the CHCH 2 species are produced by the translational activation of ethane and the dissociative ionization of ethane and ethylene, respectively. In addition, the binding energy and the vibrational spectrum of ethane adsorbed on Ni(1 1 1) are determined and exceptionally high resolution vibrational spectra of adsorbed ethylene and acetylene are presented.

Adsorption of human serum albumin: Dependence on molecular architecture of the oppositely charged surface

NASA Astrophysics Data System (ADS)

Sukhishvili, Svetlana A.; Granick, Steve

1999-05-01

We contrast the adsorption of human serum albumin (HSA) onto two solid substrates previously primed with the same polyelectrolyte of net opposite charge to form one of two alternative structures: randomly adsorbed polymer and the "brush" configuration. These structures were formed either by the adsorption of quaternized poly-4-vinylpyridine (QPVP) or by end-grafting QPVP chains of the same chemical makeup and the same molecular weight to surfaces onto which QPVP segments did not adsorb. The adsorption of HSA was quantified by using Fourier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR). The two substrates showed striking differences with regard to HSA adsorption. First, the brush substrate induced lesser perturbations in the secondary structure of the adsorbed HSA, reflecting easier conformational adjustment for longer free segments of polyelectrolyte upon binding with the protein. Second, the penetration of HSA into the brush substrate was kinetically retarded relative to the randomly adsorbed polymer, probably due to both pore size restriction and electrostatic sticking between charged groups of HSA and QPVP molecules. Third, release of HSA from the adsorbed layer, as the ionic strength was increased from a low level up to the high level of 1 M NaCl, was largely inhibited for the brush substrate, but occurred easily and rapidly for the substrate with statistically adsorbed QPVP chains. Finally, even after addition of a strong polymeric adsorption competitor (sodium polystyrene sulfonate), HSA remained trapped within a brush substrate though it desorbed slowly from the preadsorbed QPVP layer. This method to produce irreversible trapping of the protein within a brush substrate without major conformational change may find application in biosensor design.

A microengineered collagen scaffold for generating a polarized crypt-villus architecture of human small intestinal epithelium.

PubMed

Wang, Yuli; Gunasekara, Dulan B; Reed, Mark I; DiSalvo, Matthew; Bultman, Scott J; Sims, Christopher E; Magness, Scott T; Allbritton, Nancy L

2017-06-01

The human small intestinal epithelium possesses a distinct crypt-villus architecture and tissue polarity in which proliferative cells reside inside crypts while differentiated cells are localized to the villi. Indirect evidence has shown that the processes of differentiation and migration are driven in part by biochemical gradients of factors that specify the polarity of these cellular compartments; however, direct evidence for gradient-driven patterning of this in vivo architecture has been hampered by limitations of the in vitro systems available. Enteroid cultures are a powerful in vitro system; nevertheless, these spheroidal structures fail to replicate the architecture and lineage compartmentalization found in vivo, and are not easily subjected to gradients of growth factors. In the current work, we report the development of a micropatterned collagen scaffold with suitable extracellular matrix and stiffness to generate an in vitro self-renewing human small intestinal epithelium that replicates key features of the in vivo small intestine: a crypt-villus architecture with appropriate cell-lineage compartmentalization and an open and accessible luminal surface. Chemical gradients applied to the crypt-villus axis promoted the creation of a stem/progenitor-cell zone and supported cell migration along the crypt-villus axis. This new approach combining microengineered scaffolds, biophysical cues and chemical gradients to control the intestinal epithelium ex vivo can serve as a physiologically relevant mimic of the human small intestinal epithelium, and is broadly applicable to model other tissues that rely on gradients for physiological function. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reactive Carbon from Life Support Wastes for Incinerator Flue Gas Cleanup

NASA Technical Reports Server (NTRS)

Fisher, J. W.; Pisharody, S.; Moran, M. J.; Wignarajah, K.; Shi, Y.

2002-01-01

This paper presents the results from a joint research initiative between NASA Ames Research Center and Lawrence Berkeley National lab. The objective of the research is to produce activated carbon from life support wastes and to use the activated carbon to adsorb and chemically reduce the NO(sub x) and SO(sub 2) contained in incinerator flue gas. Inedible biomass waste from food production is the primary waste considered for conversion to activated carbon. Results to date show adsorption of both NO(sub x) and SO(sub 2) in activated carbon made from biomass. Conversion of adsorbed NO(sub x) to nitrogen has also been observed.

A molecular dynamics study on the adsorption of a mussel protein on two different films: Polymer film and a SAM

NASA Astrophysics Data System (ADS)

He, Cunxue; Zhang, Heng; Lin, Cunguo; Wang, Li; Yuan, Shiling

2017-05-01

The adhesion of marine life would produce a certain degree of corrosion effect on the hull surface. Shellfish organisms, such as barnacles and mussels, were always used to research the impediment of coating material to protein adsorption. In this work, the adsorbed behaviors of mussel protein on the PDMS and C7F16-SAM surfaces were explored by molecular dynamics (MD) simulations. Simulation results showed that protein was strongly adsorbed onto the hydrophobic surface, as reflected by the large interaction energy; while the adsorption onto the hydrophilic PDMS surface was weak due to two strongly adhered water layers.

Uranium from Seawater Marine Testing Program at the University of Miami’s Broad Key Island Research Station

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.

Marine testing at Broad Key Island (BKI), Florida was conducted to validate adsorption capacity and adsorption kinetics results obtained for several formulations of the ORNL amidoxime-based polymeric adsorbents in Sequim Bay, Washington in another location with different oceanographic and water quality conditions (e.g. temperature, dissolved organic carbon, salinity and trace element content). Broad Key is a small island off the southeast coast of Florida at the southern end of Biscayne Bay. Flow-through column and recirculating flume experiments were conducted at BKI using ambient filtered seawater and identical exposure systems as were used at the Pacific Northwest National Laboratory’s (PNNL) Marinemore » Sciences laboratory (MSL). Testing was conducted in two periods in FY 2015 and FY 2016 with five different amidoxime-based adsorbent materials, four produced by ORNL (AF1, AI8, AF8, and AF1-DMSO) and one by LCW technologies (LCW-10). All exposures were conducted at ambient seawater temperatures, with moderate temperature control on the ambient seawater to mitigate large daily swings in the seawater temperature. The ORNL adsorbents AF1, AI8 and AF1-AO-DMSO all had fairly similar adsorption capacities (6.0 to 6.6 g U/ kg adsorbent) after 56 days of exposure at ambient temperature (26 to 31 °C) and salinity (35.7 to 37.4), but the AF8 adsorbent was considerably lower at 4.4 g U/kg adsorbent. All the adsorbents tested at BKI had higher capacities than was observed at PNNL, with the higher temperatures likely a major factor contributing to this difference. In general, the elemental distribution (expressed as a relative percentage) on all the adsorbents agreed well, including good agreement with the elemental distribution pattern for AF1 adsorbent exposed at PNNL. The most notable exception to a uniform elemental distributional pattern across the various adsorbents occurs with vanadium. The relative mass percentage for vanadium retained by the adsorbents ranged from a minimum of 13% for the AF8 formulation to a maximum of 29% for the AI8 formulation. All the V/U mass ratios at BKI are lower than observed for the AF1 adsorbent at PNNL (3.0). Temperature likely plays a significant role in the V/U mass ratio difference between BKI and PNNL. Because uranium has a higher adsorption capacity at higher temperatures, one would expect that warmer exposures would favor a lower V/U mass ratio, which could explain why the V/U mass ratio for the PNNL exposures are higher than observed for the BKI exposures. Marine Testing at BKI offers the opportunity to test adsorbent performance under warmer ambient and more saline conditions than exist at the marine test site on Sequim Bay. This is particularly important since the amidoxime-based adsorbents respond strongly to temperature. In addition, since salinities are about 15% higher at BKI compared to Sequim Bay (36 vs. 31), uranium adsorption capacities are about 15% higher at the BKI site compared to Sequim Bay.« less

Silver-catalyzed synthesis of amides from amines and aldehydes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madix, Robert J; Zhou, Ling; Xu, Bingjun

The invention provides a method for producing amides via the reaction of aldehydes and amines with oxygen adsorbed on a metallic silver or silver alloy catalyst. An exemplary reaction is shown in Scheme 1: (I), (II), (III). ##STR00001##

Processing and Performance of MOF (Metal Organic Framework)-Loaded PAN Nanofibrous Membrane for CO2 Adsorption

NASA Astrophysics Data System (ADS)

Wahiduzzaman; Khan, Mujibur R.; Harp, Spencer; Neumann, Jeffrey; Sultana, Quazi Nahida

2016-04-01

The objective of this experimental study is to produce a nanofibrous membrane functionalized with adsorbent particles called metal organic framework (MOF) in order to adsorb CO2 from a gas source. Therefore, Polyacrylonitrile (PAN) was chosen as the precursor for nanofibers and HKUST-1, a Cu-based MOF, was chosen as adsorbent. The experimental process consists of electrospinning PAN solution blended with HKUST-1 to produce a nanofibrous mat as working substrates. The fibers were collected in a cylindrical canister model. SEM image of this mat showed nanofibers with the presence of small adsorbent particles, impregnated into the as-spun fibers discretely. To increase the amount of MOF particles for effectual gas adsorption, a secondary solvothermal process of producing MOF particles on the fibers was required. This process consists of multiple growth cycles of HKUST-1 particles by using a sol-gel precursor. SEM images showed uniform distribution of porous MOF particles of 2-4 µm in size on the fiber surface. Energy dispersive spectroscopy report of the fiber confirmed the presence of MOF particles through the identification of characteristic Copper elemental peaks of HKUST-1. To determine the thermal stability of the fibrous membrane, Thermogravimetric analysis of HKUST-1 consisting of PAN fiber was performed where a total weight loss of 40% between 210 and 360 °C was observed, hence proving the high-temperature durability of the synthesized membrane. BET surface area of the fiber membrane was measured as 540.73 m2/g. The fiber membrane was then placed into an experimental test bench containing a mixed gas inflow of CO2 and N2. Using non-dispersive infrared CO2 sensors connected to the inlet and outlet port of the bench, significant reduction of CO2 in concentration was measured. Comparative IR spectroscopic analysis between the gas-treated and gas untreated fiber samples showed the presence of characteristic peak in the vicinity of 2300 and 2400 cm-1 which verifies the adsorption of CO2.

Metabolic Heat Regenerated Temperature Swing Adsorption for CO2 and Heat Removal/Rejection in a Martian PLSS

NASA Technical Reports Server (NTRS)

Iacomini, Christine; Powers, Aaron; Bower, Chad; Straub-Lopez, Kathrine; Anderson, Grant; MacCallum, Taber; Paul, Heather L.

2007-01-01

Two of the fundamental problems facing the development of a Portable Life Support System (PLSS) for use on Mars, are (i) heat rejection (because traditional technologies use sublimation of water, which wastes a scarce resource and contaminates the premises), and (ii) rejection of carbon dioxide (CO2) in an environment with a CO2 partial pressure (ppCO2) of 0.4-0.9 kPa. Patent-pending Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed to address both these challenges. The technology utilizes an adsorbent that when cooled with liquid CO2 to near sublimation temperatures (195K) removes metabolically-produced CO2 in the ventilation loop. Once fully loaded, the adsorbent is then warmed externally by the ventilation loop (300K), rejecting the captured CO2 to Mars ambient. Two beds are used to provide a continuous cycle of CO2 removal/rejection as well as facilitate heat exchange out of the ventilation loop. Any cryogenic fluid can be used in the application; however, since CO2 is readily available on Mars and can be easily produced and stored on the Martian surface, the solution is rather elegant and less complicated when employing liquid CO2. As some metabolic heat will need to be rejected anyway, finding a practical use for metabolic heat is also an overall benefit to the PLSS. To investigate the feasibility of the technology, a series of experiments were conducted which lead to the selection and partial characterization of an appropriate adsorbent. The Molsiv Adsorbents 13X 8x12 (also known as NaX zeolite) successfully removed CO2 from a simulated ventilation loop at the prescribed temperature swing anticipated during PLSS operating conditions on Mars using a cryogenic fluid. Thermal conductivity of the adsorbent was also measured to eventually aid in a demonstrator design of the technology. These results provide no show stoppers to the development of MTSA technology and allow its development to focus on other design challenges as listed in the conclusions section of this paper.

Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

NASA Technical Reports Server (NTRS)

Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Lacomini, Christie; Paul, Heather L.

2009-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2-selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (L CO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas represents a significant source of potential energy for the warming of the adsorbent bed as it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously.

Removal of hydrogen sulfide (H2S) from biogas for the community in the province of Maha Sarakham

NASA Astrophysics Data System (ADS)

Pinate, W.; Dangphonthong, D.; Sirirach, S.; Sukkhon, S.

2017-09-01

Biogas produced from the fermentation in the province of Maha Sarakham of excreta from cow dung, fattening pigs and buffalo dung in small scale farms contained hydrogen sulfide (H2S) at 764, 926 and 1,103 ppm, respectively. This gas has offensive smell and is corrosive to motor and metal stove of farmers, thus needs to be eliminated. The adsorbent granules soaking in FeCl3 and NaOH made from grey cement mixed with diatomaceous earth or fine sand. The experiment cow dung, fattening pigs and buffalo dung farms revealed that the adsorbent granules made from fine sand mixed with grey cement had better efficiency in reducing H2S than diatomaceous earth plus grey cement or scrap iron (97.1-91.4 vs. 86.0-64.3 and 77.9-89.4%, P<0.01). The reduction of H2S increased with the increasing weight of the adsorbent tanks, made from fine sand mixed with grey cement, from 2 to 4 and 6 kg (84.1-89.2 to 92.7-98.0 and 100-99.1%, respectively). Adsorbent set of 6 kg weight can be reduced H2S in biogas from 3,141 to 0 ppm in the first day and to 6 ppm on day 25 of using period, during which the colour of adsorbent granules changed from red brown to dark brown.

Preparation of regenerable granular carbon nanotubes by a simple heating-filtration method for efficient removal of typical pharmaceuticals

NASA Astrophysics Data System (ADS)

Shan, Danna; Deng, Shubo; Zhao, Tianning; Yu, Gang; Winglee, Judith; Wiesner, Mark R.

2017-04-01

A simple and convenient method was used to prepare novel granular carbon nanotubes (CNTs) for enhanced adsorption of pharmaceuticals. By heating CNTs powder at 450 degree centigrade in air, followed by filtration, the obtained granular adsorbent exhibited high surface area and pore volume since the heating process produced some oxygen-containing functional groups on CNT surface, making CNTs more dispersible in the formation of granular cake. The porous granular CNTs not only had more available surfaces for adsorption but also were more easily separated from solution than pristine CNTs (p-CNTs) powder. This adsorbent exhibited relatively fast adsorption for carbamazepine (CBZ), tetracycline (TC) and diclofe- nac sodium (DS), and the maximum adsorption capacity on the granular CNTs was 369.5 μmol/g for CBZ, 284.2 μmol/g for TC and 203.1 μmol/g for DS according to the Langmuir fitting, increasing by 42.4%, 37.8% and 38.0% in comparison with the pristine CNTs powder. Moreover, the spent granular CNTs were successfully regenerated at 400 degree centigrade in air without decreasing the adsorption capacity in five regeneration cycles. The adsorbed CBZ and DS were completely degraded, while the adsorbed TC was partially oxidized and the residual was favorable for the subsequent adsorption. This research develops an easy method to prepare and regenerate granular CNT adsorbent for the enhanced removal of organic pollutants from water or wastewater.

Characterization of product capture resin during microbial cultivations.

PubMed

Frykman, Scott; Tsuruta, Hiroko; Galazzo, Jorge; Licari, Peter

2006-06-01

Various bioactive small molecules produced by microbial cultivation are degraded in the culture broth or may repress the formation of additional product. The inclusion of hydrophobic adsorber resin beads to capture these products in situ and remove them from the culture broth can reduce or prevent this degradation and repression. These product capture beads are often subjected to a dynamic and stressful microenvironment for a long cultivation time, affecting their physical structure and performance. Impact and collision forces can result in the fracturing of these beads into smaller pieces, which are difficult to recover at the end of a cultivation run. Various contaminating compounds may also bind in a non-specific manner to these beads, reducing the binding capacity of the resin for the product of interest (fouling). This study characterizes resin bead binding capacity (to monitor bead fouling), and resin bead volume distributions (to monitor bead fracture) for an XAD-16 adsorber resin used to capture epothilone produced during myxobacterial cultivations. Resin fouling was found to reduce the product binding capacity of the adsorber resin by 25-50%. Additionally, the degree of resin bead fracture was found to be dependent on the cultivation length and the impeller rotation rate. Microbial cultivations and harvesting processes should be designed in such a way to minimize bead fragmentation and fouling during cultivation to maximize the amount of resin and associated product harvested at the end of a run.

Characteristics of activated carbon produced from biosludge and its use in wastewater post-treatment.

PubMed

Pikkov, L; Kallas, J; Rüütmann, T; Rikmann, E

2001-02-01

Experimental research into the bench-scale production of activated carbon from waste-activated sludge from water purification, sawdust, peat, and their mixtures, by carbonisation and activation was undertaken. The research work was carried out to determine possible methods of production of cheap activated carbon from local raw materials and to use it in water purification technology. Along with the samples produced, several commercial activated carbons (namely RB-1, F 100, CA (adsorbent from military gas masks), BAY (product of the USSR)) were tested to compare adsorption properties in the adsorption of phenols, xylidines, amines, methylene blue and molasses. It has been found that the activated carbon produced from waste biosludge was of higher quality than that produced from either sawdust or peat, and performed similarly to RB-1 and F100 in adsorption tests. It was also determined that the activated carbon produced from biosludge could possibly be used in the post-treatment of wastewater. Residual sludge from the biological treatment of the wastewater from the purification of oil-shale in the chemical processing industry could cover up to 80% of the need for activated carbon. Some of this activated carbon could be used in the post-treatment of the same water, adsorbing polyalcaline phenols from the initial content of 4 mg l-1 to the demanded level of 1 mg l-1.

Book review of biochar application: Essential soil microbiology

USDA-ARS?s Scientific Manuscript database

Biochar, charcoal produced following biomass pyrolysis, has the potential to positively impact soil physical and chemical properties, improving soil fertility and water holding capacity as well as adsorbing contaminants. In addition, a large proportion of biochar carbon is highly recalcitrant and s...

The use of sugar and alcohol industry waste in the adsorption of potentially toxic metals.

PubMed

Santos, Oseas Silva; Mendonça, André Gustavo Ribeiro; Santos, Josué Carinhanha Caldas; Silva, Amanda Paulina Bezerra; Costa, Silvanio Silverio Lopes; Oliveira, Luciana Camargo; Carmo, Janaina Braga; Botero, Wander Gustavo

2016-01-01

One of the waste products of the industrial process of the sugar and alcohol agribusiness is filter cake (FC). This waste product has high levels of organic matter, mainly proteins and lipids, and is rich in calcium, nitrogen, potassium and phosphorous. In this work we characterized samples of FC from sugar and alcohol industries located in sugarcane-producing regions in Brazil and assessed the adsorption of potentially toxic metals (Cu(II), Cd(II), Pb(II), Ni(II) and Cr(III)) by this waste in mono- and multi-elemental systems, seeking to use FC as an adsorbent in contaminated environments. The characterization of FCs showed significant differences between the samples and the adsorption studies showed retention of over 90% of potentially toxic metals. In a competitive environment (multi-metallic solution), the FC was effective in adsorbing all metals except lead, but less effective compared to the mono-metallic solution. These results show the potential for use of this residue as an adsorbent in contaminated environments.

Evaluation of the performance of biochars as an adsorbent for polycyclic aromatic hydrocarbons

NASA Astrophysics Data System (ADS)

Jung, J.; Kang, S.; Ok, Y.; Choi, Y.

2016-12-01

Biochars, byproducts generated by pyrolysis of biomass, are known to have several advantages as a soil amendment such as carbon sequestration effect, enhancement of soil microbial activity, and nutrient supply. Because of their high surface area and affinity to organic pollutants, biochars are also being evaluated as an adsorbent for hydrophobic organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) in soils, stormwater, and wastewater. Depending on their organic precursors and pyrolysis temperatures, biochars have been shown to have various physicochemical properties, which should determine their performance as an adsorbent for hydrophobic organic pollutants. In this study, we obtained biochars derived from soybean stover, wood chip, rice husk, and sewage sludge with pyrolysis temperatures of 700°, 250°, 500°, and 500°, respectively, to investigate their performance for PAH adsorption. Adsorption kinetic and isotherm experiments were conducted using naphthalene and phenanthrene as model compounds. Soybean stover biochar reached close to equilibrium in 7 days while the others did in 25 days in the kinetic experiments. The first-order sorption rate constants were greater for naphthalene than for phenanthrene for all biochars studied, and they were generally in the order of soybean stover>rice husk>sewage sludge>wood chip biochars for the two contaminants. The removal rates of aqueous PAHs at equilibrium were in the order of soybean stover>rice husk>sewage sludge>wood chip biochars at a concentration range of a few ng/mL. The results suggested that the sorption capability and the rate is generally greater for biochar produced from plant materials than that from sludge, and for biochar produced at higher pyrolysis temperature. Comparing the sorption properties of the biochars and granular activated carbon (GAC), it is shown that biochar produced at optimal conditions can exhibit performance for PAH adsorption similar to GAC.

Microsystems in medicine.

PubMed

Wallrabe, U; Ruther, P; Schaller, T; Schomburg, W K

1998-03-01

The complexity of modern surgical and analytical methods requires the miniaturisation of many medical devices. The LIGA technique and also mechanical microengineering are well known for the batch fabrication of microsystems. Actuators and sensors are developed based on these techniques. The hydraulic actuation principle is advantageous for medical applications since the energy may be supplied by pressurised balanced salt solution. Some examples are turbines, pumps and valves. In addition, optical sensors and components are useful for analysis and inspection as represented by microspectrometers and spherical lenses. Finally, plastic containers with microporous bottoms allow a 3-dimensional growth of cell culture systems.

Multistep synthesis on SU-8: combining microfabrication and solid-phase chemistry on a single material.

PubMed

Cavalli, Gabriel; Banu, Shahanara; Ranasinghe, Rohan T; Broder, Graham R; Martins, Hugo F P; Neylon, Cameron; Morgan, Hywel; Bradley, Mark; Roach, Peter L

2007-01-01

SU-8 is an epoxy-novolac resin and a well-established negative photoresist for microfabrication and microengineering. The photopolymerized resist is an extremely highly crosslinked polymer showing outstanding chemical and physical robustness with residual surface epoxy groups amenable for chemical functionalization. In this paper we describe, for the first time, the preparation and surface modification of SU-8 particles shaped as microbars, the attachment of appropriate linkers, and the successful application of these particles to multistep solid-phase synthesis leading to oligonucleotides and peptides attached in an unambiguous manner to the support surface.

Modeling and optimization of the hot embossing process for micro- and nanocomponent fabrication

NASA Astrophysics Data System (ADS)

Worgull, M.; Heckele, Mathias P.; Hétu, J. F.; Kabanemi, K. K.

2006-01-01

Hot embossing and injection molding belong to the established plastic molding processes in microengineering. Based on experimental findings, a variety of microstructures have been replicated using these processes. However, with increasing requirements regarding the embossing surface, and the simultaneous decrease of the structure size down into the nanorange, increasing know-how is needed to adapt hot embossing to industrial standards. To reach this objective, a German-Canadian cooperation project has been launched to study hot embossing theoretically by process simulation and experimentally. The present publication reports on the proceeding and present first results.

Automotive sensors: past, present and future

NASA Astrophysics Data System (ADS)

Prosser, S. J.

2007-07-01

This paper will provide a review of past, present and future automotive sensors. Today's vehicles have become highly complex sophisticated electronic control systems and the majority of innovations have been solely achieved through electronics and the use of advanced sensors. A range of technologies have been used over the past twenty years including silicon microengineering, thick film, capacitive, variable reluctance, optical and radar. The automotive sensor market continues to grow with respect to vehicle production level in recognition of the transition to electronically controlled electrically actuated systems. The environment for these sensors continues to be increasingly challenging with respect to robustness, reliability, quality and cost.

Evaluation of polymeric adsorbent resins for efficient detoxification of liquor generated during acid pretreatment of lignocellulosic biomass.

PubMed

Sandhya, Soolamkandath Variem; Kiran, Kumar; Kuttiraja, Mathiyazhakan; Preeti, Varghese Elizabeth; Sindhu, Raveendran; Vani, Sankar; Kumar, Sukumaran Rajeev; Pandey, Ashok; Binod, Parameswaran

2013-11-01

Production of fuel ethanol from lignocellulosic biomass conventionally includes biomass pretreatment, hydrolysis, and fermentation. The liquor generated during dilute acid pretreatment of biomass contains considerable quantities of pentose sugars as well as various degradation products of sugars and lignin, like furfural, hydroxymethyl furfural (HMF), organic acids, aldehydes and others, which are known to be inhibitory for microbial growth. This pentose rich liquor is a potent resource which can be used to produce alcohol or other value added metabolites by microbial fermentation. However, the presence of these inhibitory compounds is a major hindrance and their removal is essential for efficient utilization of this byproduct stream. In the present work, the polymeric adsorbent resins, XAD-4, XAD-7 and XAD-16 were evaluated for their ability to adsorb fermentation inhibitors like furfural and HMF from the acid pretreated liquor. These resins could remove 55-75% of furfural and 100% of HMF and more than 90% sugar remained un-adsorbed in the pretreated liquor. Desorption of furfural from stationary phase was evaluated by using ethanol and hot water. The results suggest that these polymeric resins may be used for detoxification of acid pretreatment liquor with selective removal of sugar degradation products without affecting the sugar content in the solution.

Development Trends in Porous Adsorbents for Carbon Capture.

PubMed

Sreenivasulu, Bolisetty; Sreedhar, Inkollu; Suresh, Pathi; Raghavan, Kondapuram Vijaya

2015-11-03

Accumulation of greenhouse gases especially CO2 in the atmosphere leading to global warming with undesirable climate changes has been a serious global concern. Major power generation in the world is from coal based power plants. Carbon capture through pre- and post- combustion technologies with various technical options like adsorption, absorption, membrane separations, and chemical looping combustion with and without oxygen uncoupling have received considerable attention of researchers, environmentalists and the stake holders. Carbon capture from flue gases can be achieved with micro and meso porous adsorbents. This review covers carbonaceous (organic and metal organic frameworks) and noncarbonaceous (inorganic) porous adsorbents for CO2 adsorption at different process conditions and pore sizes. Focus is also given to noncarbonaceous micro and meso porous adsorbents in chemical looping combustion involving insitu CO2 capture at high temperature (>400 °C). Adsorption mechanisms, material characteristics, and synthesis methods are discussed. Attention is given to isosteric heats and characterization techniques. The options to enhance the techno-economic viability of carbon capture techniques by integrating with CO2 utilization to produce industrially important chemicals like ammonia and urea are analyzed. From the reader's perspective, for different classes of materials, each section has been summarized in the form of tables or figures to get a quick glance of the developments.

Synthesis of Microporous Materials and Their VSC Adsorption Properties

NASA Astrophysics Data System (ADS)

Yokogawa, Y.; Morikawa, H.; Sakanishi, M.; Utaka, H.; Nakamura, A.; Kishida, I.

2011-10-01

Oral malodor is caused by volatile sulfur compounds (VSC) such as hydrogen sulfide (H2S), methyl mercaptan and dimethyl sulfide produced in mouth. VSC induces permeability of mucous membrane and oral malodor formation. Thus, the adsorbent which highly adsorbs VSC should be useful for health in mouth and may prevent teeth from decaying. The microporous material, hydrotalcite, was synthesized by a wet method, and the H2S adsorption was studied. The samples, identified by powder X-ray diffraction method, were put into glass flask filled with H2S gas. The initial concentration of H2S was 30 ppm. The change in concentrations of H2S was measured at rt, and the amount of H2S absorbed on the hydrotalcite for 24 h was 300 micro L/g. The samples were taken out from the above glass flask and put into a pyrolysis plant attached to gas chromatography-mass spectrometry to determine the amount of H2S desorbed from samples. Only 3 % of H2S was desorbed when heated at 500 °C. H2S in water was also found to adsorb into hydrotalcite, which was confirmed by the headspace gas chromatography with flame photometric detector. The hydrotalcite material should be expected to be an adsorbent material, useful for health in mouth.

Monitoring and removal of cyanobacterial toxins from drinking water by algal-activated carbon.

PubMed

Ibrahim, Wael M; Salim, Emad H; Azab, Yahia A; Ismail, Abdel-Hamid M

2016-10-01

Microcystins (MCs) are the most potent toxins that can be produced by cyanobacteria in drinking water supplies. This study investigated the abundance of toxin-producing algae in 11 drinking water treatment plants (DWTPs). A total of 26 different algal taxa were identified in treated water, from which 12% were blue green, 29% were green, and 59% were diatoms. MC levels maintained strong positive correlations with number of cyanophycean cells in raw and treated water of different DWTPs. Furthermore, the efficiency of various algal-based adsorbent columns used for the removal of these toxins was evaluated. The MCs was adsorbed in the following order: mixed algal-activated carbon (AAC) ≥ individual AAC > mixed algal powder > individual algal powder. The results showed that the AAC had the highest efficient columns capable of removing 100% dissolved MCs from drinking water samples, thereby offering an economically feasible technology for efficient removal and recovery of MCs in DWTPs. © The Author(s) 2015.

The influence of activating agents on the performance of rice husk-based carbon for sodium lauryl sulfate and chrome (Cr) metal adsorptions

NASA Astrophysics Data System (ADS)

Arneli; Safitri, Z. F.; Pangestika, A. W.; Fauziah, F.; Wahyuningrum, V. N.; Astuti, Y.

2017-02-01

This research aims to study the influence of activating agents to produce rice husk based-carbon with high adsorption capacity and efficiency for either hazardous organic molecules or heavy metals which are unfriendly for the environment. Firstly, rice husk was burned by pyrolysis at different temperatures to produce rice husk-based carbon. To improve its ability as an adsorbent, carbon was treated with activating agents, namely, H3PO4 and KOH at room and high temperature (420 °C). The performance of carbon was then tested by contacting it with surfactant (SLS). Finally, the surfactant-modified active carbon was applied for chrome metal removal. The result shows that activation of carbon using phosphate acid (H3PO4) was more effective than potassium hydroxide (KOH) conducted at high temperature to adsorb sodium lauryl sulfate (SLS) and chrome metal with the adsorption capacity 1.50 mgg-1 and 0.375 mgg-1, respectively.

Activated bauxite waste as an adsorbent for removal of Acid Blue 92 from aqueous solutions.

PubMed

Norouzi, Sh; Badii, Kh; Doulati Ardejani, F

2010-01-01

Bauxite waste, known as red mud, is produced in some industrial processes, such as aluminum production process. In this process, the waste material is produced from leached bauxite as a by product. In this research, the removal of Acid Blue 92 (AB92) dye was investigated from aqueous solution onto the activated bauxite waste (red mud) in a batch equilibration system. Besides, the influences of pH, adsorbent dosage, contact time, initial concentration of dye and temperature have been considered. It was found that the OH group is an effective functional group for the adsorption process. The intensity of the peaks correspond to OH group has been significantly climbed after the activation process. The adsorption kinetics of AB92 can be well described by the pseudo-second-order reaction model. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Langmuir model appears to fit the adsorption process better than the Freundlich and Brunauer-Emmett-Teller (BET) models.

Highly efficient adsorption of cationic dye by biochar produced with Korean cabbage waste.

PubMed

Sewu, Divine D; Boakye, Patrick; Woo, Seung H

2017-01-01

Biochar was produced from Korean cabbage (KC), rice straw (RS) and wood chip (WC) and the use as alternative adsorbents to activated carbon (AC) in wastewater treatment was investigated. Congo red (CR) and crystal violet (CV) were used as a model anionic and cationic dye, respectively. Initial solution pH had little effect on CR and CV adsorption onto all biochars except for AC on CR. The isotherm models and kinetic data showed that adsorption of CR and CV onto all biochars were dominantly by chemisorption. All biochars had lower adsorption capacity for CR than AC. KC showed higher Langmuir maximum adsorption capacity (1304mg/g) than AC (271.0mg/g), RS (620.3mg/g) and WC (195.6mg/g) for CV. KC may be a good alternative to conventional AC as cheap, superb and industrially viable adsorbent for removal of cationic dyes in wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isothermal approach to predict the removal efficiency of β-carotene adsorption from CPO using activated carbon produced from tea waste

NASA Astrophysics Data System (ADS)

Harahap, S. A. A.; Nazar, A.; Yunita, M.; Pasaribu, RA; Panjaitan, F.; Yanuar, F.; Misran, E.

2018-02-01

Adsorption of β-carotene in crude palm oil (CPO) was studied using activated carbon produced from tea waste (ACTW) an adsorbent. Isothermal studies were carried out at 60 °C with the ratio of activated carbon to CPO were 1:3, 1:4, 1:5, and 1:6, respectively. The ACTW showed excellent performance as the percentage of adsorption of β-carotene from CPO was > 99%. The best percentage removal (R) was achieved at ACTW to CPO ratio equal to 1:3, which was 99.61%. The appropriate isotherm model for this study was Freundlich isotherm model. The combination of Freundlich isotherm equation and mass balance equation showed a good agreement when validated to the experimental data. The equation subsequently executed to predict the removal efficiency under given sets of operating conditions. At a targetted R, CPO volume can be estimated for a certain initial concentration β-carotene in CPO C0 and mass of ACTW adsorbent M used.

Clays and other minerals in prebiotic processes

NASA Technical Reports Server (NTRS)

Paecht-Horowitz, M.

1984-01-01

Clays and other minerals have been investigated in context with prebiotic processes, mainly in polymerization of amino acids. It was found that peptides adsorbed on the clay, prior to polymerization, influence the reaction. The ratio between the amount of the peptides adsorbed and that of the clay is important for the yield as well as for the degrees of polymerization obtained. Adsorption prior to reaction produces a certain order in the aggregates of the clay particles which might induce better reaction results. Excess of added peptides disturbs this order and causes lesser degrees of polymerization. In addition to adsorption, clays are also able to occlude between their layers substances out of the environment, up to very high concentrations.

Simultaneous removal of potent cyanotoxins from water using magnetophoretic nanoparticle of polypyrrole: adsorption kinetic and isotherm study.

PubMed

Hena, S; Rozi, R; Tabassum, S; Huda, A

2016-08-01

Cyanotoxins, microcystins and cylindrospermopsin, are potent toxins produced by cyanobacteria in potable water supplies. This study investigated the removal of cyanotoxins from aqueous media by magnetophoretic nanoparticle of polypyrrole adsorbent. The adsorption process was pH dependent with maximum adsorption occurring at pH 7 for microcystin-LA, LR, and YR and at pH 9 for microcystin-RR and cylindrospermopsin (CYN). Kinetic studies and adsorption isotherms reflected better fit for pseudo-second-order rate and Langmuir isotherm model, respectively. Thermodynamic calculations showed that the cyanotoxin adsorption process is endothermic and spontaneous in nature. The regenerated adsorbent can be successfully reused without appreciable loss of its original capacity.

Green Adsorbents for Wastewaters: A Critical Review

PubMed Central

Kyzas, George Z.; Kostoglou, Margaritis

2014-01-01

One of the most serious environmental problems is the existence of hazardous and toxic pollutants in industrial wastewaters. The major hindrance is the simultaneous existence of many/different types of pollutants as (i) dyes; (ii) heavy metals; (iii) phenols; (iv) pesticides and (v) pharmaceuticals. Adsorption is considered to be one of the most promising techniques for wastewater treatment over the last decades. The economic crisis of the 2000s led researchers to turn their interest in adsorbent materials with lower cost. In this review article, a new term will be introduced, which is called “green adsorption”. Under this term, it is meant the low-cost materials originated from: (i) agricultural sources and by-products (fruits, vegetables, foods); (ii) agricultural residues and wastes; (iii) low-cost sources from which most complex adsorbents will be produced (i.e., activated carbons after pyrolysis of agricultural sources). These “green adsorbents” are expected to be inferior (regarding their adsorption capacity) to the super-adsorbents of previous literature (complex materials as modified chitosans, activated carbons, structurally-complex inorganic composite materials etc.), but their cost-potential makes them competitive. This review is a critical approach to green adsorption, discussing many different (maybe in some occasions doubtful) topics such as: (i) adsorption capacity; (ii) kinetic modeling (given the ultimate target to scale up the batch experimental data to fixed-bed column calculations for designing/optimizing commercial processes) and (iii) critical techno-economical data of green adsorption processes in order to scale-up experiments (from lab to industry) with economic analysis and perspectives of the use of green adsorbents. PMID:28788460

Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate

DOE PAGES

Zhao, Wei; Doyle, Andrew D.; Morgan, Sawyer E.; ...

2017-11-21

Here, the dissociative adsorption of carboxylic acids on oxide surfaces is important for understanding adsorbed carboxylates, which are important as intermediates in catalytic reactions, for the organo-functionalization of oxide surfaces, and in many other aspects of oxide surface chemistry. We present here the first direct experimental measurement of the heat of dissociative adsorption of any carboxylic acid on any single-crystal oxide surface. The enthalpy of the dissociative adsorption of formic acid, the simplest carboxylic acid, to produce adsorbed formate and hydrogen (as a surface hydroxyl) on a (2 × 2)-NiO(111) surface is measured by single crystal adsorption calorimetry. The differentialmore » heat of adsorption decreases with formic acid coverage from 202 to 99 kJ/mol at saturation (0.25 ML). The structure of the adsorbed products is clarified by density functional theory (DFT) calculations, which provide energies in reasonable agreement with the calorimetry. These calculations show that formic acid readily dissociates on both the oxygen and Ni terminations of the octapolar NiO(111) surfaces, donating its acid H to a surface lattice oxygen, while HCOO adsorbs preferentially with bridging-type geometry near the M-O 3/O-M 3 sites. The calculated energetics at low coverages agrees well with experimental data, while larger differences are observed at high coverage (0.25 ML). The large decrease in experimental heat of adsorption with coverage can be brought into agreement with the DFT energies if we assume that both types of octapolar surface terminations (O- and Ni-) are present on the starting surface.« less

Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Wei; Doyle, Andrew D.; Morgan, Sawyer E.

Here, the dissociative adsorption of carboxylic acids on oxide surfaces is important for understanding adsorbed carboxylates, which are important as intermediates in catalytic reactions, for the organo-functionalization of oxide surfaces, and in many other aspects of oxide surface chemistry. We present here the first direct experimental measurement of the heat of dissociative adsorption of any carboxylic acid on any single-crystal oxide surface. The enthalpy of the dissociative adsorption of formic acid, the simplest carboxylic acid, to produce adsorbed formate and hydrogen (as a surface hydroxyl) on a (2 × 2)-NiO(111) surface is measured by single crystal adsorption calorimetry. The differentialmore » heat of adsorption decreases with formic acid coverage from 202 to 99 kJ/mol at saturation (0.25 ML). The structure of the adsorbed products is clarified by density functional theory (DFT) calculations, which provide energies in reasonable agreement with the calorimetry. These calculations show that formic acid readily dissociates on both the oxygen and Ni terminations of the octapolar NiO(111) surfaces, donating its acid H to a surface lattice oxygen, while HCOO adsorbs preferentially with bridging-type geometry near the M-O 3/O-M 3 sites. The calculated energetics at low coverages agrees well with experimental data, while larger differences are observed at high coverage (0.25 ML). The large decrease in experimental heat of adsorption with coverage can be brought into agreement with the DFT energies if we assume that both types of octapolar surface terminations (O- and Ni-) are present on the starting surface.« less

Biology of Streptococcus mutans-Derived Glucosyltransferases: Role in Extracellular Matrix Formation of Cariogenic Biofilms

PubMed Central

Bowen, W.H.; Koo, H.

2011-01-01

The importance of Streptococcus mutans in the etiology and pathogenesis of dental caries is certainly controversial, in part because excessive attention is paid to the numbers of S. mutans and acid production while the matrix within dental plaque has been neglected. S. mutans does not always dominate within plaque; many organisms are equally acidogenic and aciduric. It is also recognized that glucosyltransferases from S. mutans (Gtfs) play critical roles in the development of virulent dental plaque. Gtfs adsorb to enamel synthesizing glucans in situ, providing sites for avid colonization by microorganisms and an insoluble matrix for plaque. Gtfs also adsorb to surfaces of other oral microorganisms converting them to glucan producers. S. mutans expresses 3 genetically distinct Gtfs; each appears to play a different but overlapping role in the formation of virulent plaque. GtfC is adsorbed to enamel within pellicle whereas GtfB binds avidly to bacteria promoting tight cell clustering, and enhancing cohesion of plaque. GtfD forms a soluble, readily metabolizable polysaccharide and acts as a primer for GtfB. The behavior of soluble Gtfs does not mirror that observed with surface-adsorbed enzymes. Furthermore, the structure of polysaccharide matrix changes over time as a result of the action of mutanases and dextranases within plaque. Gtfs at distinct loci offer chemotherapeutic targets to prevent caries. Nevertheless, agents that inhibit Gtfs in solution frequently have a reduced or no effect on adsorbed enzymes. Clearly, conformational changes and reactions of Gtfs on surfaces are complex and modulate the pathogenesis of dental caries in situ, deserving further investigation. PMID:21346355

Biological effect of microengineered grooved stents on strut healing: a randomised OCT-based comparative study in humans

PubMed Central

Vesga, Boris; Hernandez, Hector; Higuera, Sergio; Gasior, Pawel; Echeveri, Dario; Delgado, Juan A; Dager, Antonio; Arana, Camilo; Simonton, Charles; Maehara, Akiko; Palmaz, Julio; Granada, Juan F

2017-01-01

Objective To evaluate the biological effect of microengineered stent grooves (MSG) on early strut healing in humans by performing optical coherence tomography (OCT) analysis 3 weeks following the implantation. Background In the experimental setting, MSG accelerate endothelial cell migration and reduce neointimal proliferation compared with bare metal stent (BMS). Methods A total of 37 patients undergoing percutaneous coronary intervention with de novo coronary lesions were randomly assigned to either MSG (n=19) or an identical BMS controls (n=18). All patients underwent OCT imaging at 3 weeks. A total of 7959 struts were included in the final analysis. Results At 3 weeks following stent implantation, almost all struts analysed (~97%) had evidence of tissue coverage. The percentage of partially covered struts was comparable between both groups. However, the percentage of fully embedded struts was higher in the BMS group (81.22%, 49.75–95.52) compared with the MSG group (74.21%, 58.85–86.38). The stent-level analysis demonstrated reduction in neointimal formation (neointimal hyperplasia area and volume reduction of ~14% and ~19%, respectively) in the MSG versus the BMS group. In the strut-level analysis, an even greater reduction (~22% in neointimal thickness) was seen in the MSG group. Layered neointimal was present in ~6% of the OCT frames in the BMS group while it was not present in the MSG group. Conclusions MSG induced a more homogeneous and predictable pattern of surface healing in the early stages following stent implantation. The biological effect of MSG on stent healing has the potential to improve the safety profile of current generation drug-eluting stents. Classifications BMS, OCT, clinical trials. PMID:28674616

Biological effect of microengineered grooved stents on strut healing: a randomised OCT-based comparative study in humans.

PubMed

Vesga, Boris; Hernandez, Hector; Higuera, Sergio; Gasior, Pawel; Echeveri, Dario; Delgado, Juan A; Dager, Antonio; Arana, Camilo; Simonton, Charles; Maehara, Akiko; Palmaz, Julio; Granada, Juan F

2017-01-01

To evaluate the biological effect of microengineered stent grooves (MSG) on early strut healing in humans by performing optical coherence tomography (OCT) analysis 3 weeks following the implantation. In the experimental setting, MSG accelerate endothelial cell migration and reduce neointimal proliferation compared with bare metal stent (BMS). A total of 37 patients undergoing percutaneous coronary intervention with de novo coronary lesions were randomly assigned to either MSG (n=19) or an identical BMS controls (n=18). All patients underwent OCT imaging at 3 weeks. A total of 7959 struts were included in the final analysis. At 3 weeks following stent implantation, almost all struts analysed (~97%) had evidence of tissue coverage. The percentage of partially covered struts was comparable between both groups. However, the percentage of fully embedded struts was higher in the BMS group (81.22%, 49.75-95.52) compared with the MSG group (74.21%, 58.85-86.38). The stent-level analysis demonstrated reduction in neointimal formation (neointimal hyperplasia area and volume reduction of ~14% and ~19%, respectively) in the MSG versus the BMS group. In the strut-level analysis, an even greater reduction (~22% in neointimal thickness) was seen in the MSG group. Layered neointimal was present in ~6% of the OCT frames in the BMS group while it was not present in the MSG group. MSG induced a more homogeneous and predictable pattern of surface healing in the early stages following stent implantation. The biological effect of MSG on stent healing has the potential to improve the safety profile of current generation drug-eluting stents. BMS, OCT, clinical trials.

A novel instrument for studying the flow behaviour of erythrocytes through microchannels simulating human blood capillaries.

PubMed

Sutton, N; Tracey, M C; Johnston, I D; Greenaway, R S; Rampling, M W

1997-05-01

A novel instrument has been developed to study the microrheology of erythrocytes as they flow through channels of dimensions similar to human blood capillaries. The channels are produced in silicon substrates using microengineering technology. Accurately defined, physiological driving pressures and temperatures are employed whilst precise, real-time image processing allows individual cells to be monitored continuously during their transit. The instrument characterises each cell in a sample of ca. 1000 in terms of its volume and flow velocity profile during its transit through a channel. The unique representation of the data in volume/velocity space provides new insight into the microrheological behaviour of blood. The image processing and subsequent data analysis enable the system to reject anomalous events such as multiple cell transits, thereby ensuring integrity of the resulting data. By employing an array of microfluidic flow channels we can integrate a number of different but precise and highly reproducible channel sizes and geometries within one array, thereby allowing multiple, concurrent isobaric measurements on one sample. As an illustration of the performance of the system, volume/velocity data sets recorded in a microfluidic device incorporating multiple channels of 100 microns length and individual widths ranging between 3.0 and 4.0 microns are presented.

Unraveling shock-induced chemistry using ultrafast lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, David Steven

The exquisite time synchronicity between shock and diagnostics needed to unravel chemical events occurring in picoseconds has been achieved using a shaped ultrafast laser pulse to both drive the shocks and interrogate the sample via a multiplicity of optical diagnostics. The shaped laser drive pulse can produce well-controlled shock states of sub-ns duration with sub-10 ps risetimes, sufficient for investigation offast reactions or phase transformations in a thin layer with picosecond time resolution. The shock state is characterized using ultrafast dynamic ellipsometry (UDE) in either planar or Gaussian spatial geometries, the latter allowing measurements of the equation of state ofmore » materials at a range of stresses in a single laser pulse. Time-resolved processes in materials are being interrogated using UDE, ultrafast infrared absorption, ultrafast UV/visible absorption, and femtosecond stimulated Raman spectroscopy. Using these tools we showed that chemistry in an energetic thin film starts only after an induction time of a few tens of ps, an observation that allows differentiation between proposed shock-induced reaction mechanisms. These tools are presently being applied to a variety of energetic and reactive sample systems, from nitromethane and carbon disulfide, to microengineered interfaces in tunable energetic mixtures. Recent results will be presented, and future trends outlined.« less

Electrophoretic deposition of thermites onto micro-engineered electrodes prepared by direct-ink writing.

PubMed

Sullivan, K T; Zhu, C; Tanaka, D J; Kuntz, J D; Duoss, E B; Gash, A E

2013-02-14

This work combines electrophoretic deposition (EPD) with direct-ink writing (DIW) to prepare thin films of Al/CuO thermites onto patterned two- and three-dimensional silver electrodes. DIW was used to write the electrodes using a silver nanoparticle ink, and EPD was performed in a subsequent step to deposit the thermite onto the conductive electrodes. Unlike conventional lithographic techniques, DIW is a low-cost and versatile alternative to print fine-featured electrodes, and adds the benefit of printing self-supported three-dimensional structures. EPD provides a method for depositing the composite thermite only onto the conductive electrodes, and with controlled thicknesses, which provides fine spatial and mass control, respectively. EPD has previously been shown to produce well-mixed thermite composites which can pack to reasonably high densities without the need for any postprocessing. Homogeneous mixing is particularly important in reactive composities, where good mixing can enhance the reaction kinetics by decreasing the transport distance between the components. Several two- and three-dimensional designs were investigated to highlight the versatility of using DIW and EPD together. In addition to energetic applications, we anticipate that this combination of techniques will have a variety of other applications, which would benefit from the controlled placement of a thin film of one material onto a conductive architecture of a second material.

Environmental aspects of produced-water salt releases in onshore and coastal petroleum-producing areas of the conterminous U.S. - a bibliography

USGS Publications Warehouse

Otton, James K.

2006-01-01

Environmental effects associated with the production of oil and gas have been reported since the first oil wells were drilled in the Appalachian Basin in Pennsylvania and Kentucky in the early to mid-1800s. The most significant of these effects are the degradation of soils, ground water, surface water, and ecosystems they support by releases of suspended and dissolved hydrocarbons and co-produced saline water. Produced water salts are less likely than hydrocarbons to be adsorbed by mineral phases in the soil and sediment and are not subject to degradation by biologic processes. Sodium is a major dissolved constituent in most produced waters and it causes substantial degradation of soils through altering of clays and soil textures and subsequent erosion. Produced water salts seem to have the most wide-ranging effects on soils, water quality, and ecosystems. Trace elements, including boron, lithium, bromine, fluorine, and radium, also occur in elevated concentrations in some produced waters. Many trace elements are phytotoxic and are adsorbed and may remain in soils after the saline water has been flushed away. Radium-bearing scale and sludge found in oilfield equipment and discarded on soils pose additional hazards to human health and ecosystems. This bibliography includes studies from across the oil- and natural-gas-producing areas of the conterminous United States that were published in the last 80 yrs. The studies describe the effects of produced water salts on soils, water quality, and ecosystems. Also included are reports that describe (1) the inorganic chemistry of produced waters included in studies of formation waters for various purposes, (2) other sources of salt affecting water quality that may be mistaken for produced water effects, (3) geochemical and geophysical techniques that allow discrimination of salt sources, (4) remediation technologies designed to repair damage caused to soils and ground water by produced water salts, and (5) contamination by naturally occurring radioactive materials (NORM)at oilfield sites.

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

NASA Astrophysics Data System (ADS)

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/AC can be regenerated for several times without any significant loss in the performance.

Shock compression and flash-heating of molecular adsorbates on the picosecond time scale

NASA Astrophysics Data System (ADS)

Berg, Christopher Michael

An ultrafast nonlinear coherent laser spectroscopy termed broadband multiplex vibrational sum-frequency generation (SFG) with nonresonant suppression was employed to monitor vibrational transitions of molecular adsorbates on metallic substrates during laser-driven shock compression and flash-heating. Adsorbates were in the form of well-ordered self-assembled monolayers (SAMs) and included molecular explosive simulants, such as nitroaromatics, and long chain-length alkanethiols. Based on reflectance measurements of the metallic substrates, femtosecond flash-heating pulses were capable of producing large-amplitude temperature jumps with DeltaT = 500 K. Laser-driven shock compression of SAMs produced pressures up to 2 GPa, where 1 GPa ≈ 1 x 104 atm. Shock pressures were estimated via comparison with frequency shifts observed in the monolayer vibrational transitions during hydrostatic pressure measurements in a SiC anvil cell. Molecular dynamics during flash-heating and shock loading were probed with vibrational SFG spectroscopy with picosecond temporal resolution and sub-nanometer spatial resolution. Flash-heating studies of 4-nitrobenzenethiolate (NBT) on Au provided insight into effects from hot-electron excitation of the molecular adsorbates at early pump-probe delay times. At longer delay times, effects from the excitation of SAM lattice modes and lower-energy NBT vibrations were shown. In addition, flash-heating studies of alkanethiolates demonstrated chain disordering behaviors as well as interface thermal conductances across the Au-SAM junction, which was of specific interest within the context of molecular electronics. Shock compression studies of molecular explosive simulants, such as 4-nitrobenzoate (NBA), demonstrated the proficiency of this technique to observe shock-induced molecular dynamics, in this case orientational dynamics, on the picosecond time scale. Results validated the utilization of these refined shock loading techniques to probe the shock initiation or first bond-breaking reactions in molecular explosives such as delta-HMX: a necessary study for the development of safer and more effective energetic materials.

Flow-induced conformational changes in gelatin structure and colloidal stabilization.

PubMed

Akbulut, Mustafa; Reddy, Naveen K; Bechtloff, Bernd; Koltzenburg, Sebastian; Vermant, Jan; Prud'homme, Robert K

2008-09-02

Flow can change the rate at which solutes adsorb on surfaces by changing mass transfer to the surface, but moreover, flow can induce changes in the conformation of macromolecules in solution by providing sufficient stresses to perturb the segmental distribution function. However, there are few studies where the effect of flow on macromolecules has been shown to alter the structure of macromolecules adsorbed on surfaces. We have studied how the local energy dissipation alters the adsorption of gelatin onto polystyrene nanoparticles ( r = 85 nm). The change in the nature of the adsorbed layer is manifest in the change in the ability of the nanoparticles to resist aggregation. Circular dichroism spectroscopy was used to assess conformational changes in gelatin, and dynamic light scattering was used to assess the colloid stability. Experiments were conducted in a vortex jet mixer where energy density and mixing times have been quantified; mixing of the gelatin and unstable nanoparticles occurs on the order of milliseconds. The adsorption of the gelatin provides steric stabilization to the nanoparticles. We found that the stability of the gelatin-adsorbed nanoparticles increased with increasing mixing velocities: when the mixing velocities were changed from 0.9 to 550 m/s, the radius of the nanoclusters (aggregates) formed 12 h after the mixing decreased from 2620 to 600 nm. Increasing temperature also gave rise to similar trends in the stability behavior with increasing temperature, leading to increasing colloid stability. Linear flow birefringence studies also suggested that the velocity fields in the mixer are sufficiently strong to produce conformational changes in the gelatin. These results suggest that the energy dissipation produced by mixing can activate conformational changes in gelatin to alter its adsorption on the surfaces of nanoparticles. Understanding how such conformational changes in gelatin can be driven by local fluid mechanics and how these changes are related to the adsorption behavior of gelatin is very important both industrially and scientifically.

Improved method for producing catalytic carbon and the potential for increasing its use in commercial applications

USGS Publications Warehouse

Kruse, C.W.; Lizzio, A.A.; DeBarr, J.A.; Feizoulof, C.A.

1997-01-01

This paper describes an improved method for producing a catalytic carbon, which was first produced in the late 1960s. The new activated carbon (AC) removes and destroys organic pollutants in aqueous solutions. To determine the effects of altering the pore structure and surface chemistry of activated carbons, carbons differing in the amount of functional groups on their surfaces were prepared in three steps: (1) oxidizing AC with boiling nitric acid, (2) washing oxidized AC with water to remove the acid, and (3) heating oxidized AC to temperatures beteween 100 and 925 ??C. The surfaces of the products were characterized by determining the amount of CO2 and CO evolved during temperature-programmed desorption. Depending on the desorption temperature, these modified carbons showed enhanced adsorptive and/or catalytic properties that included (1) carbon molecular sieves for separating oxygen from nitrogen, (2) increased capacity for adsorbing sulfur dioxide, (3) stronger adsorption of p-nitrophenol from water, and (4) catalysis of dehydrochlorination reactions. A dehydrohalogenation catalyst produced by the oxidation/ desorption steps was found to be similar to one prepared in the 1960s by oxidizing AC with air at 500-700 ??C. The dehydrohalogenation catalyst produced by either the old method or the new method involves an oxidized surface that has been exposed to a 500-700 ??C temperature range. This carbon catalyst retains modified adsorptive properties of the AC from which it is produced. It can be used both to adsorb pollutants from liquid or gaseous streams and to convert them to recyclable products.

Performance Tests of High Speed ZRV Oil Skimmer.

DTIC Science & Technology

1980-06-01

clarified by recirculation through a 2,000 gpm diatomaceous earth filter system to permit full use of a sophisticated underwater photography and video...generator and beach, and a filter system. The wave generator and adsorber beach have capabilities of producing regular waves to 2.25 feet high and to 92

Predicting performance of almonds shells for cleanup of almond soil fumigants from potable water.

USDA-ARS?s Scientific Manuscript database

Almond shell strength and bulk density were determined to differ significantly among almond varieties, and further research demonstrated that granular activated carbons (GAC) produced from shells of different varieties had similar abilities to adsorb DBCP from contaminated water. As an extension of...

Polymer-phyllosilicate nanocomposites and their preparation

DOEpatents

Chaiko, David J.

2007-01-09

Polymer-phyllosilicate nanocomposites that exhibit superior properties compared to the polymer alone, and methods-for producing these polymer-phyllosilicate nanocomposites, are provided. Polymeric surfactant compatabilizers are adsorbed onto the surface of hydrophilic or natural phyllosilicates to facilitate the dispersal and exfoliation of the phyllosilicate in a polymer matrix. Utilizing polymeric glycol based surfactants, polymeric dicarboxylic acids, polymeric diammonium surfactants, and polymeric diamine surfactants as compatabilizers facilitates natural phyllosilicate and hydrophilic organoclay dispersal in a polymer matrix to produce nanocomposites.

Effective, Low-Cost Recovery of Toxic Arsenate Anions from Water by Using Hollow-Sphere Geode Traps.

PubMed

Shenashen, Mohamed A; Akhtar, Naeem; Selim, Mahmoud M; Morsy, Wafaa M; Yamaguchi, Hitoshi; Kawada, Satoshi; Alhamid, Abdulaziz A; Ohashi, Naoki; Ichinose, Izumi; Alamoudi, Ahmad S; El-Safty, Sherif A

2017-08-04

Because of the devastating impact of arsenic on terrestrial and aquatic organisms, the recovery, removal, disposal, and management of arsenic-contaminated water is a considerable challenge and has become an urgent necessity in the field of water treatment. This study reports the controlled fabrication of a low-cost adsorbent based on microscopic C-,N-doped NiO hollow spheres with geode shells composed of poly-CN nanospherical nodules (100 nm) that were intrinsically stacked and wrapped around the hollow spheres to form a shell with a thickness of 500-700 nm. This C-,N-doped NiO hollow-sphere adsorbent (termed CNN) with multiple diffusion routes through open pores and caves with connected open macro/meso windows over the entire surface and well-dispersed hollow-sphere particles that create vesicle traps for the capture, extraction, and separation of arsenate (AsO 4 3- ) species from aqueous solution. The CNN structures are considered to be a potentially attractive adsorbent for AsO 4 3- species due to 1) superior removal and trapping capacity from water samples and 2) selective trapping of AsO 4 3- from real water samples that mainly contained chloride and nitrate anions and Fe 2+ , and Mn 2+ , Ca 2+ , and Mg 2+ cations. The structural stability of the hierarchal geodes was evident after 20 cycles without any significant decrease in the recovery efficiency of AsO 4 3- species. To achieve low-cost adsorbents and toxic-waste management, this superior CNN AsO 4 3- dead-end trapping and recovery system evidently enabled the continuous control of AsO 4 3- disposal in water-scarce environments, presents a low-cost and eco-friendly adsorbent for AsO 4 3- species, and selectively produced water-free arsenate species. These CNN geode traps show potential as excellent adsorbent candidates in environment remediation tools and human healthcare. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adsorption of elemental mercury vapors from synthetic exhaust combustion gas onto HGR carbon.

PubMed

Musmarra, D; Karatza, D; Lancia, A; Prisciandaro, M; Mazziotti di Celso, G

2016-07-01

An activated carbon commercially available named HGR, produced by Calgon-Carbon Group, was used to adsorbe metallic mercury. The work is part of a wider research activity by the same group focused on the removal of metallic and divalent mercury from combustion flue gas. With respect to previously published papers, this one is aimed at studying in depth thermodynamic equilibria of metallic mercury adsorption onto a commercial activated carbon. The innovativeness lies in the wider operative conditions explored (temperature and mercury concentrations) and in the evaluation of kinetic and thermodynamic data for a commercially available adsorbing material. In detail, experimental runs were carried out on a laboratory-scale plant, in which Hg° vapors were supplied in a nitrogen gas stream at different temperature and mercury concentration. The gas phase was flowed through a fixed bed of adsorbent material. Adsorbate loading curves for different Hg° concentrations together with adsorption isotherms were achieved as a function of temperature (120, 150, 200°C) and Hg° concentrations (1.0-7.0 mg/m(3)). Experimental runs demonstrated satisfying results of the adsorption process, while Langmuir parameters were evaluated with gas-solid equilibrium data. Especially, they confirmed that adsorption capacity is a favored process in case of lower temperature and they showed that the adsorption heat was -20 kJ/mol. Furthermore, a numerical integration of differential equations that model the adsorption process was proposed. Scanning electron microscopy (SEM) investigation was an useful tool to investigate about fresh and saturated carbon areas. The comparison between them allowed identification of surface sites where mercury is adsorbed; these spots correspond to carbon areas where sulfur concentration is greater. Mercury compounds can cause severe harm to human health and to the ecosystem. There are a lot of sources that emit mercury species to the atmosphere; the main ones are exhaust gases from coal combustion and municipal solid waste incineration. Furthermore, certain CO2 capture processes, particularly oxyfuel combustion in a pulverized fuel coal-fired power station, produce a raw CO2 product containing several contaminants, mainly water vapor, oxygen, and nitrogen but also mercury, that have to be almost completely removed; otherwise these would represent a strong drawback to the success of the process.

Using degrees of rate control to improve selective n-butane oxidation over model MOF-encapsulated catalysts: sterically-constrained Ag 3 Pd(111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dix, Sean T.; Scott, Joseph K.; Getman, Rachel B.

2016-01-01

Metal nanoparticles encapsulated within metal organic frameworks (MOFs) offer steric restrictions near the catalytic metal that can improve selectivity, much like in enzymes. A microkinetic model is developed for the regio-selective oxidation ofn-butane to 1-butanol with O 2over a model for MOF-encapsulated bimetallic nanoparticles. The model consists of a Ag 3Pd(111) surface decorated with a 2-atom-thick ring of (immobile) helium atoms which creates an artificial pore of similar size to that in common MOFs, which sterically constrains the adsorbed reaction intermediates. The kinetic parameters are based on energies calculated using density functional theory (DFT). The microkinetic model was analysed atmore » 423 K to determine the dominant pathways and which species (adsorbed intermediates and transition states in the reaction mechanism) have energies that most sensitively affect the reaction rates to the different products, using degree-of-rate-control (DRC) analysis. This analysis revealed that activation of the C–H bond is assisted by adsorbed oxygen atoms, O*. Unfortunately, O* also abstracts H from adsorbed 1-butanol and butoxy as well, leading to butanal as the only significant product. This suggested to (1) add water to produce more OH*, thus inhibiting these undesired steps which produce OH*, and (2) eliminate most of the O 2pressure to reduce the O* coverage, thus also inhibiting these steps. Combined with increasing butane pressure, this dramatically improved the 1-butanol selectivity (from 0 to 95%) and the rate (to 2 molecules per site per s). Moreover, 40% less O 2was consumed per oxygen atom in the products. Under these conditions, a terminal H in butane is directly eliminated to the Pd site, and the resulting adsorbed butyl combines with OH* to give the desired 1-butanol. These results demonstrate that DRC analysis provides a powerful approach for optimizing catalytic process conditions, and that highly selectivity oxidation can sometimes be achieved by using a mixture of O 2and H 2O as the oxidant. This was further demonstrated by DRC analysis of a second microkinetic model based on a related but hypothetical catalyst, where the activation energies for two of the steps were modified.« less

Molecular Electronic Devices Based On Electrooptical Behavior Of Heme-Like Molecules

NASA Astrophysics Data System (ADS)

Simic-Glavaski, B.

1986-02-01

This paper discusses application of the electrically modulated and unusually strong Raman emitted light produced by an adsorbed monolayer of phthalocyanine molecules on silver electrode or silver bromide substrates and on neural membranes. The analysis of electronic energy levels in semiconducting silver bromide and the adsorbed phthalocyanine molecules suggests a lasing mechanism as a possible origin of the high enhancement factor in surface enhanced Raman scattering. Electrically modulated Raman scattering may be used as a carrier of information which is drawn fran the fast intramolecular electron transfer aN,the multiplicity of quantum wells in phthalocyanine molecules. Fast switching times on the order of 10-13 seconds have been measured at room temperature. Multilevel and multioutput optical signals have also been obtained fran such an electrically modulated adsorbed monolayer of phthalocyanine molecules which can be precisely addressed and interrogated. This may be of practical use to develop Nlecular electronic devices with high density memory and fast parallel processing systems with a typical 1020 gate Hz/cm2 capacity at room temperature for use in optical computers. The paper also discusses the electrooptical modulation of Raman signals obtained from adsorbed bio-compatible phthalocyanine molecules on nerve membranes. This optical probe of neural systems can be used in studies of complex information processing in neural nets and provides a possible method for interfacing natural and man-made information processing devices.

Environmental Effects on Zirconium Hydroxide Nanoparticles and Chemical Warfare Agent Decomposition: Implications of Atmospheric Water and Carbon Dioxide.

PubMed

Balow, Robert B; Lundin, Jeffrey G; Daniels, Grant C; Gordon, Wesley O; McEntee, Monica; Peterson, Gregory W; Wynne, James H; Pehrsson, Pehr E

2017-11-15

Zirconium hydroxide (Zr(OH) 4 ) has excellent sorption properties and wide-ranging reactivity toward numerous types of chemical warfare agents (CWAs) and toxic industrial chemicals. Under pristine laboratory conditions, the effectiveness of Zr(OH) 4 has been attributed to a combination of diverse surface hydroxyl species and defects; however, atmospheric components (e.g., CO 2 , H 2 O, etc.) and trace contaminants can form adsorbates with potentially detrimental impact to the chemical reactivity of Zr(OH) 4 . Here, we report the hydrolysis of a CWA simulant, dimethyl methylphosphonate (DMMP) on Zr(OH) 4 determined by gas chromatography-mass spectrometry and in situ attenuated total reflectance Fourier transform infrared spectroscopy under ambient conditions. DMMP dosing on Zr(OH) 4 formed methyl methylphosphonate and methoxy degradation products on free bridging and terminal hydroxyl sites of Zr(OH) 4 under all evaluated environmental conditions. CO 2 dosing on Zr(OH) 4 formed adsorbed (bi)carbonates and interfacial carbonate complexes with relative stability dependent on CO 2 and H 2 O partial pressures. High concentrations of CO 2 reduced DMMP decomposition kinetics by occupying Zr(OH) 4 active sites with carbonaceous adsorbates. Elevated humidity promoted hydrolysis of adsorbed DMMP on Zr(OH) 4 to produce methanol and regenerated free hydroxyl species. Hydrolysis of DMMP by Zr(OH) 4 occurred under all conditions evaluated, demonstrating promise for chemical decontamination under diverse, real-world conditions.

Nanoscale water condensation on click-functionalized self-assembled monolayers.

PubMed

James, Michael; Ciampi, Simone; Darwish, Tamim A; Hanley, Tracey L; Sylvester, Sven O; Gooding, J Justin

2011-09-06

We have examined the nanoscale adsorption of molecular water under ambient conditions onto a series of well-characterized functionalized surfaces produced by Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC or "click") reactions on alkyne-terminated self-assembled monolayers on silicon. Water contact angle (CA) measurements reveal a range of macroscopic hydrophilicity that does not correlate with the tendency of these surfaces to adsorb water at the molecular level. X-ray reflectometry has been used to follow the kinetics of water adsorption on these "click"-functionalized surfaces, and also shows that dense continuous molecular water layers are formed over 30 h. For example, a highly hydrophilic surface, functionalized by an oligo(ethylene glycol) moiety (with a CA = 34°) showed 2.9 Å of adsorbed water after 30 h, while the almost hydrophobic underlying alkyne-terminated monolayer (CA = 84°) showed 5.6 Å of adsorbed water over the same period. While this study highlights the capacity of X-ray reflectometry to study the structure of adsorbed water on these surfaces, it should also serve as a warning for those intending to characterize self-assembled monolayers and functionalized surfaces to avoid contamination by even trace amounts of water vapor. Moreover, contact angle measurements alone cannot be relied upon to predict the likely degree of moisture uptake on such surfaces. © 2011 American Chemical Society

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

PubMed

Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

2013-10-01

Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane. Copyright © 2013 Elsevier Ltd. All rights reserved.

Selective capture of iodide from solutions by microrosette-like δ-Bi₂O₃.

PubMed

Liu, Long; Liu, Wei; Zhao, Xiaoliang; Chen, Daimei; Cai, Rongsheng; Yang, Weiyou; Komarneni, Sridhar; Yang, Dongjiang

2014-09-24

Radioactive iodine isotopes that are produced in nuclear power plants and used in medical research institutes could be a serious threat to the health of many people if accidentally released to the environment because the thyroid gland can absorb and concentrate them from a liquid. For this reason, uptake of iodide anions was investigated on microrosette-like δ-Bi2O3 (MR-δ-Bi2O3). The MR-δ-Bi2O3 adsorbent showed a very high uptake capacity of 1.44 mmol g(-1) by forming insoluble Bi4I2O5 phase. The MR-δ-Bi2O3 also displayed fast uptake kinetics and could be easily separated from a liquid after use because of its novel morphology. In addition, the adsorbent showed excellent selectivity for I(-) anions in the presence of large concentrations of competitive anions such as Cl(-) and CO3(2-), and could work in a wide pH range of 4-11. This study led to a new and highly efficient Bi-based adsorbent for iodide capture from solutions.

Plasmid DNA loaded chitosan nanoparticles for nasal mucosal immunization against hepatitis B.

PubMed

Khatri, Kapil; Goyal, Amit K; Gupta, Prem N; Mishra, Neeraj; Vyas, Suresh P

2008-04-16

This work investigates the preparation and in vivo efficacy of plasmid DNA loaded chitosan nanoparticles for nasal mucosal immunization against hepatitis B. Chitosan pDNA nanoparticles were prepared using a complex coacervation process. Prepared nanoparticles were characterized for size, shape, surface charge, plasmid loading and ability of nanoparticles to protect DNA against nuclease digestion and for their transfection efficacy. Nasal administration of nanoparticles resulted in serum anti-HBsAg titre that was less compared to that elicited by naked DNA and alum adsorbed HBsAg, but the mice were seroprotective within 2 weeks and the immunoglobulin level was above the clinically protective level. However, intramuscular administration of naked DNA and alum adsorbed HBsAg did not elicit sIgA titre in mucosal secretions that was induced by nasal immunization with chitosan nanoparticles. Similarly, cellular responses (cytokine levels) were poor in case of alum adsorbed HBsAg. Chitosan nanoparticles thus produced humoral (both systemic and mucosal) and cellular immune responses upon nasal administration. The study signifies the potential of chitosan nanoparticles as DNA vaccine carrier and adjuvant for effective immunization through non-invasive nasal route.

Ochratoxin degradation and adsorption caused by astaxanthin-producing yeasts.

PubMed

Péteri, Z; Téren, J; Vágvölgyi, C; Varga, J

2007-05-01

Ochratoxin degrading and adsorbing activities of Phaffia rhodozyma and Xanthophyllomyces dendrorhous isolates were tested. P. rhodozyma CBS 5905 degraded more than 90% of ochratoxin A (OTA) in 15 days at 20 degrees C. The data presented indicate that P. rhodozyma is able to convert OTA to ochratoxin alpha, and this conversion is possibly mediated by an enzyme related to carboxypeptidases. Chelating agents like EDTA and 1,10-phenanthroline inhibited OTA degradation caused by P. rhodozyma indicating that the carboxypeptidase is a metalloprotease, similarly to carboxypeptidase A. The temperature optimum of this enzyme was found to be above 30 degrees C, which is much higher than the temperature optimum for growth of P. rhodozyma cells, which is around 20 degrees C. The enzyme responsible for ochratoxin degradation was found to be cell-bound. Besides, both viable and heat-treated (dead) P. rhodozyma cells were also able to adsorb significant amounts (up to 250 ng ml(-1)) of OTA. Heat treatment enhanced OTA adsorbing activities of the cells. Further studies are in progress to identify the enzyme responsible for OTA degradation in P. rhodozyma.

Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption

DOEpatents

Ghate, Madhav R.; Yang, Ralph T.

1987-01-01

Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon, zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high parity hydrogen from gaseous products of coal gasification and as an acid gas scrubber.

Development of the protocol for purification of artemisinin based on combination of commercial and computationally designed adsorbents.

PubMed

Piletska, Elena V; Karim, Kal; Cutler, Malcolm; Piletsky, Sergey A

2013-01-01

A polymeric adsorbent for extraction of the antimalarial drug artemisinin from Artemisia annua L. was computationally designed. This polymer demonstrated a high capacity for artemisinin (120 mg g(-1) ), quantitative recovery (87%) and was found to be an effective material for purification of artemisinin from complex plant matrix. The artemisinin quantification was conducted using an optimised HPLC-MS protocol, which was characterised by high precision and linearity in the concentration range between 0.05 and 2 μg mL(-1) . Optimisation of the purification protocol also involved screening of commercial adsorbents for the removal of waxes and other interfering natural compounds, which inhibit the crystallisation of artemisinin. As a result of a two step-purification protocol crystals of artemisinin were obtained, and artemisinin purity was evaluated as 75%. By performing the second stage of purification twice, the purity of artemisinin can be further improved to 99%. The developed protocol produced high-purity artemisinin using only a few purification steps that makes it suitable for large scale industrial manufacturing process. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of Nisin and Fibrinogen Adsorption on Poly(ethylene Oxide) Coated Polyurethane Surfaces by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

PubMed Central

Schilke, Karl F.; McGuire, Joseph

2011-01-01

Stable, pendant polyethylene oxide (PEO) layers were formed on medical-grade Pellethane® and Tygon® polyurethane surfaces, by adsorption and gamma-irradiation of PEO-polybutadiene-PEO triblock surfactants. Coated and uncoated polyurethanes were challenged individually or sequentially with nisin (a small polypeptide with antimicrobial activity) and/or fibrinogen, and then analyzed with time-of-flight secondary ion mass spectrometry (TOF-SIMS). Data reduction by robust principal components analysis (PCA) allowed detection of outliers, and distinguished adsorbed nisin and fibrinogen. Fibrinogen-contacted surfaces, with or without nisin, were very similar on uncoated polymer surfaces, consistent with nearly complete displacement or coverage of previously-adsorbed nisin by fibrinogen. In contrast, nisin-loaded PEO layers remained essentially unchanged upon challenge with fibrinogen, suggesting that the adsorbed nisin is stabilized within the pendant PEO layer, while the peptide-loaded PEO layer retains its ability to repel large proteins. Coatings of PEO loaded with therapeutic polypeptides on medical polymers have the potential to be used to produce anti-fouling and biofunctional surfaces for implantable or blood-contacting devices. PMID:21440897

Quality characteristics of Bali sardinella (Sardinella lemuru) oil purified with bentonite as an adsorbent

NASA Astrophysics Data System (ADS)

Nadhiro, U.; Subekti, S.; Tjahjaningsih, W.; Patmawati

2018-04-01

Crude fish oil extracted from fish canning industry a low quality, therefore refining process is required to obtain feasible fish oil for food purposes. Purification of fish oil can through steps of degumming, neutralization, and bleaching by using bentonite as the adsorbent. This study aims to analyze the results of the purification process of crude fish oil by-product of canning industry of lemuru fish by using bentonite adsorbent with different concentrations. The method used was an experimental method by descriptive data analysis. The results showed that the highest yield (33.418 %) obtained from oil purification of lemuru with bentonite concentration of 6 % are classified as follows: free fatty acid content of 0.265 %, peroxide value of 6.343 mEq / kg, produce clarity 60.275 % T, 88.075 % T, 87.5 % T, 87.425 % T, 87.975 % T at a wavelength (λ) of 450 nm, 550 nm, 620 nm, 665 nm, 700 nm, para-anisidine value of 3.725 mEq / kg; and value of oxidation total of 16.41 meq / kg.

Process and apparatus for the production of hydrogen by steam reforming of hydrocarbon

DOEpatents

Sircar, Shivaji; Hufton, Jeffrey Raymond; Nataraj, Shankar

2000-01-01

In the steam reforming of hydrocarbon, particularly methane, under elevated temperature and pressure to produce hydrogen, a feed of steam and hydrocarbon is fed into a first reaction volume containing essentially only reforming catalyst to partially reform the feed. The balance of the feed and the reaction products of carbon dioxide and hydrogen are then fed into a second reaction volume containing a mixture of catalyst and adsorbent which removes the carbon dioxide from the reaction zone as it is formed. The process is conducted in a cycle which includes these reactions followed by countercurrent depressurization and purge of the adsorbent to regenerate it and repressurization of the reaction volumes preparatory to repeating the reaction-sorption phase of the cycle.

Photodynamic dye adsorption and release performance of natural zeolite

NASA Astrophysics Data System (ADS)

Hovhannisyan, Vladimir; Dong, Chen-Yuan; Chen, Shean-Jen

2017-03-01

Clinoptilolite type of zeolite (CZ) is a promising material for biomedicine and pharmaceutics due to its non-toxicity, thermal stability, expanded surface area, and exceptional ability to adsorb various atoms and organic molecules into micropores. Using multiphoton microscopy, we demonstrated that individual CZ particles produce two-photon excited luminescence and second harmonic generation signal at femtosecond laser excitation, and adsorb photo-dynamically active dyes such as hypericin and methylene blue. Furthermore, the release of hypericin from CZ pores in the presence of biomolecules is shown, and CZ can be considered as an effective material for drug delivery and controlled release in biological systems. The results may open new perspectives in application of CZ in biomedical imaging, and introducing of the optical approaches into the clinical environment.

Photodynamic dye adsorption and release performance of natural zeolite.

PubMed

Hovhannisyan, Vladimir; Dong, Chen-Yuan; Chen, Shean-Jen

2017-03-31

Clinoptilolite type of zeolite (CZ) is a promising material for biomedicine and pharmaceutics due to its non-toxicity, thermal stability, expanded surface area, and exceptional ability to adsorb various atoms and organic molecules into micropores. Using multiphoton microscopy, we demonstrated that individual CZ particles produce two-photon excited luminescence and second harmonic generation signal at femtosecond laser excitation, and adsorb photo-dynamically active dyes such as hypericin and methylene blue. Furthermore, the release of hypericin from CZ pores in the presence of biomolecules is shown, and CZ can be considered as an effective material for drug delivery and controlled release in biological systems. The results may open new perspectives in application of CZ in biomedical imaging, and introducing of the optical approaches into the clinical environment.

Selectivity switch for nitrogen functionalization of styrene on Au(1 1 1)

NASA Astrophysics Data System (ADS)

Deng, Xingyi; Friend, Cynthia M.

2008-03-01

Functionalization of styrene to form N-containing hydrocarbons, e.g. 2-phenylaziridine, benzonitrile, and benzyl nitrile, is achieved by reaction with adsorbed NH a and N a on Au(1 1 1). Electron-induced decomposition of condensed NH 3 was used to produce NH a, N a and H a on Au(1 1 1) at 110 K. The selectivity of the reactions is strongly dependent on the relative concentrations of the surface species. The addition of NH to styrene results in the production of 2-phenylaziridine, whereas adsorbed N and H atoms lead to the formation of nitriles benzonitrile and benzyl nitrile and, respectively, ethylbenzene. This work clearly establishes the utility of Au for promoting functionalization of olefins with nitrogen.

Dyes removal from water using low cost absorbents

NASA Astrophysics Data System (ADS)

Giraldo, S.; Ramirez, A. P.; Ulloa, M.; Flórez, E.; Y Acelas, N.

2017-12-01

In this study, the removal capacity of low cost adsorbents during the adsorption of Methylene Blue (MB) and Congo Red (CR) at different concentrations (50 and 100mg·L-1) was evaluated. These adsorbents were produced from wood wastes (cedar and teak) by chemical activation (ZnCl2). Both studied materials, Activated Cedar (AC) and activated teak (AT) showed a good fit of their experimental data to the pseudo second order kinetic model and Langmuir isotherms. The maximum adsorption capacities for AC were 2000.0 and 444.4mg·g-1 for MB and CR, respectively, while for AT, maximum adsorption capacities of 1052.6 and 86.4mg·g-1 were found for MB and CR, respectively.

Thermo-rheological behaviour of polymer melts in microinjection moulding

NASA Astrophysics Data System (ADS)

Vasco, J. C.; Maia, J. M.; Pouzada, A. S.

2009-10-01

Microinjection has proven to be one of the most efficient replication methods for microcomponents and microsystems in various domains of microengineering. The use of available commercial microinjection equipment to evaluate the polymeric flow in microchannels would surely contribute to enhancing knowledge on polymeric flow at the microscale under industrial conditions. This approach is appropriate since rheological phenomena such as wall slip, surface tension, melt pressure drop and polymer flow length can be studied. These aspects are not fully dealt with in current commercial simulation software packages. In this study a micromould was designed to assess and characterize the flow in microchannels under realistic industrial conditions.

A novel photochemical machining process for magnesium aerospace and biomedical microengineering applications

NASA Astrophysics Data System (ADS)

Allen, D. M.; Simpkins, M.; Almond, H.

2010-10-01

Research was carried out to evaluate the feasibility of fabricating perforated (filigree) magnesium microcomponents with metal wire widths of the order of the metal thickness using a photochemical machining (PCM) process. Experimentally, it has been demonstrated for the first time that metal wire widths of 0.15 mm can be achieved within a 2D, 0.25 mm thick magnesium foil to fabricate microcomponents for use as micro air vehicle (MAV) wings or stents through a bespoke PCM process. This etching process differs significantly from the industrial etching process used currently to manufacture magnesium letterpress printing plates and embossing dies.

Laser Embossing of Micro-and Submicrometer Surface Structures in Copper

NASA Astrophysics Data System (ADS)

Ehrhardt, Martin; Lorenz, Pierre; Frost, Frank; Zimmer, Klaus

Micro- and submicrometer structures have been transferred from nickel foils into solid copper surfaces by laser microembossing. The developed arrangement for laser microembossing allows a large-area replication using multi- pulse laser scanning scheme, guaranties a low contamination of the embossed surface and enables the utilization of thick workpieces. In the micrometer range the replicated patterns feature a high accuracy regarding the shape. A significant difference between the master and the replication pattern could be observed for the laser embossing of submicrometer patterns. In conclusion, the results show that the proposed laser embossing process is a promising method with a number of applications in microengineering.

The Theory for the Mechanism of Chromium Plating: The Theory for the Physical Characteristics of Chromium Plate

DTIC Science & Technology

1947-01-01

first, to produce a cathode film containing highly reducing atomic hydro- gen, and, second , to raise the cathode film pH above that of the solution...those of a face-centered cubic structure with a lattice parameter (a0) of 3.84 A. It was concluded that a second unstable structure of chrom- ium...plates similar to those produced from cathode films of relatively low pH, Second , the sulphate ion is strongly adsorbed by the trivalent chromium

Electron-stimulated reactions in nanoscale water films adsorbed on α-Al 2 O 3 (0001)

DOE PAGES

Petrik, Nikolay G.; Kimmel, Greg A.

2018-01-01

100 eV electrons are stopped in the H 2 O portion of the isotopically-layered nanoscale film on α-Al 2 O 3 (0001) but D 2 is produced at the D 2 O/alumina interface by mobile electronic excitations and/or hydronium ions.

Preparation and characterization of degradable nanocapsules that release pesticides over an extended period of time

USDA-ARS?s Scientific Manuscript database

Pesticide efficacy is limited by evaporation and precipitation. These processes can result in the need for costly pesticide re-application. By using a nanocapsule to contain the pesticide, these two problems can be greatly reduced. Produced nanocapsules adsorb on the surface of the plant and are not...

A DFT study on photoinduced surface catalytic coupling reactions on nanostructured silver: selective formation of azobenzene derivatives from para-substituted nitrobenzene and aniline.

PubMed

Zhao, Liu-Bin; Huang, Yi-Fan; Liu, Xiu-Min; Anema, Jason R; Wu, De-Yin; Ren, Bin; Tian, Zhong-Qun

2012-10-05

We propose that aromatic nitro and amine compounds undergo photochemical reductive and oxidative coupling, respectively, to specifically produce azobenzene derivatives which exhibit characteristic Raman signals related to the azo group. A photoinduced charge transfer model is presented to explain the transformations observed in para-substituted ArNO(2) and ArNH(2) on nanostructured silver due to the surface plasmon resonance effect. Theoretical calculations show that the initial reaction takes place through excitation of an electron from the filled level of silver to the lowest unoccupied molecular orbital (LUMO) of an adsorbed ArNO(2) molecule, and from the highest occupied molecular orbital (HOMO) of an adsorbed ArNH(2) molecule to the unoccupied level of silver, during irradiation with visible light. The para-substituted ArNO(2)(-)˙ and ArNH(2)(+)˙ surface species react further to produce the azobenzene derivatives. Our results may provide a new strategy for the syntheses of aromatic azo dyes from aromatic nitro and amine compounds based on the use of nanostructured silver as a catalyst.

Synthesis, characterization and thermodynamic study of carbon dioxide adsorption on akaganéite

DOE PAGES

Roque-Malherbe, R.; Lugo, F.; Rivera-Maldonado, C.; ...

2015-04-01

A mixture of akaganeite nanoparticles and sodium salts was synthesized and modi fied, first by washing, and then by Li exchange. The structural characterization of the produced materials was performed with: powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectrometry, Mossbauer spectros- € copy and magnetization measurements. Additionally low pressure nitrogen and high pressure carbon dioxide adsorption experiments were performed. The sum of the characterization information made possible to conclude that the produced akaganeite phases crystallized in a structure exhibiting the symmetry of the I2/m space group, where the measured equivalentmore » spherical diameter of the akaganeite crystallites yielded 9 nm, as well, the tested phases exhibited a standard behaviour under heating and displayed a superparamagnetic behaviour. Finally the high pressure carbon dioxide adsorption experiments demonstrated a pressure-responsive framework opening event due to a structural transformation of the adsorbent framework induced by the guest molecules. This fact opens new applications for akaganeite as a high pressure adsorbent.« less

Optimized Production of Coal Fly Ash Derived Synthetic Zeolites for Mercury Removal from Wastewater

NASA Astrophysics Data System (ADS)

Tauanov, Z.; Shah, D.; Itskos, G.; Inglezakis, V.

2017-09-01

Coal fly ash (CFA) derived synthetic zeolites have become popular with recent advances and its ever-expanding range of applications, particularly as an adsorbent for water and gas purification and as a binder or additive in the construction industry and agriculture. Among these applications, perpetual interest has been in utilization of CFA derived synthetic zeolites for removal of heavy metals from wastewater. We herein focus on utilization of locally available CFA for efficient adsorption of mercury from wastewater. To this end, experimental conditions were investigated so that to produce synthetic zeolites from Kazakhstani CFAs with conversion into zeolite up to 78%, which has remarkably high magnetite content. In particular, the effect of synthesis reaction temperature, reaction time, and loading of adsorbent were systematically investigated and optimized. All produced synthetic zeolites and the respective CFAs were characterized using XRD, XRF, PSA and porosimetric instruments to obtain microstructural and mineralogical data. Furthermore, the synthesized zeolites were studied for the removal of mercury from aqueous solutions. A comparison of removal eficiency and its relationship to the physical and chemical properties of the synthetic zeolites were analyzed and interpreted.

DFT study of CO2 conversion on InZr3(110) surface.

PubMed

Zhang, Minhua; Dou, Maobin; Yu, Yingzhe

2017-11-01

Methanol and methane synthesis from CO 2 hydrogenation on a InZr 3 (110) surface has been studied using density functional theory calculations. The CO 2 can be chemically adsorbed via a polydentated configuration and the H 2 molecule can dissociate to H atoms spontaneously. The methanol is primarily formed via the HCOO route instead of the RWGS route, due to its higher activation barrier of 1.35 eV for HCO hydrogenation. In the HCOO route, the adsorbed CO 2 consecutively hydrogenates to form HCOO, H 2 COO and the H 3 CO species. The H 3 COH is produced via the reaction of H 3 CO with a surface OH group. Furthermore, the C-O bonds of CO, CHO, CH 2 O and CH 3 O species prefer to dissociate to C, CH, CH 2 CH 3 and surface O species. Methane is formed via the hydrogenation of CH x (x = 0-3) monomers with the highest activation barrier of 1.19 eV for CH 3 hydrogenation, which is higher than that of the hydrogenation of H 2 COO in methanol synthesis via the HCOO route. The surface O species formed during CO 2 hydrogenation reacts with the adsorbed H 2 molecule to produce an OH group which reacts with a surface H atom to form H 2 O with an activation barrier of 1.13 eV, which then desorbs to the gas phase. Our calculated results indicate that the InZr 3 alloy is a potential candidate catalyst for CO 2 utilization and conversion.

Camptothecin-producing endophytic fungus Trichoderma atroviride LY357: isolation, identification, and fermentation conditions optimization for camptothecin production.

PubMed

Pu, Xiang; Qu, Xixing; Chen, Fei; Bao, Jinku; Zhang, Guolin; Luo, Yinggang

2013-11-01

Camptothecin (CPT), the third largest anticancer drug, is produced mainly by Camptotheca acuminata and Nothapodytes foetida. CPT itself is the starting material for clinical CPT-type drugs, but the plant-derived CPT cannot support the heavy demand from the global market. Research efforts have been made to identify novel sources for CPT. In this study, three CPT-producing endophytic fungi, Aspergillus sp. LY341, Aspergillus sp. LY355, and Trichoderma atroviride LY357, were isolated and identified from C. acuminata. Most CPT produced by these fungi was found in the fermentation broth, and their corresponding CPT yields were 7.93, 42.92, and 197.82 μg l(-1), respectively. The CPT-producing capability of LY341 and LY355 was completely lost after repeat subculturing. A substantial decrease of CPT production was also observed in the second generation of LY357. However, a stable and sustainable production of CPT was found from the second generation through the eighth generation of LY357. The fermentation medium, time, pH, temperature, and agitation rate were optimized for CPT production. Methyl jasmonate and XAD16 were proven to be an optimum elicitor and adsorbent resin, respectively, in view of that CPT yield was increased 3.4- and 11-fold through their use. A 50- to 75-fold increase of CPT yield was obtained when the optimized fermentation conditions, elicitor, and adsorbent resin were combined and applied to the culture of the seventh and eighth generations of LY357, and the highest CPT yield was 142.15 μg l(-1). The CPT-producing T. atroviride LY357 paves a potential to uncover the mysteries of CPT biosynthesis.

Adsorption and oxidation of SO₂in a fixed-bed reactor using activated carbon produced from oxytetracycline bacterial residue and impregnated with copper.

PubMed

Zhou, Baohua; Yu, Lei; Song, Hanning; Li, Yaqi; Zhang, Peng; Guo, Bin; Duan, Erhong

2015-02-01

The SO₂removal ability (including adsorption and oxidation ability) of activated carbon produced from oxytetracycline bacterial residue and impregnated with copper was investigated. The activated carbon produced from oxytetracycline bacterial residue and modified with copper was characterized by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The effects of the catalysts, SO₂concentration, weight hourly space velocity, and temperature on the SO₂adsorption and oxidation activity were evaluated. Activated carbon produced from oxytetracycline bacterial residue and used as catalyst supports for copper oxide catalysts provided high catalytic activity for the adsorbing and oxidizing of SO₂from flue gases.

Photodynamic dye adsorption and release performance of natural zeolite

PubMed Central

Hovhannisyan, Vladimir; Dong, Chen-Yuan; Chen, Shean-Jen

2017-01-01

Clinoptilolite type of zeolite (CZ) is a promising material for biomedicine and pharmaceutics due to its non-toxicity, thermal stability, expanded surface area, and exceptional ability to adsorb various atoms and organic molecules into micropores. Using multiphoton microscopy, we demonstrated that individual CZ particles produce two-photon excited luminescence and second harmonic generation signal at femtosecond laser excitation, and adsorb photo-dynamically active dyes such as hypericin and methylene blue. Furthermore, the release of hypericin from CZ pores in the presence of biomolecules is shown, and CZ can be considered as an effective material for drug delivery and controlled release in biological systems. The results may open new perspectives in application of CZ in biomedical imaging, and introducing of the optical approaches into the clinical environment. PMID:28361968

URANIUM RECOVERY AND PURIFICATION PROCESS AND PRODUCTION OF HIGH PURITY URANIUM TETRAFLUORIDE

DOEpatents

Bailes, R.H.; Long, R.S.; Grinstead, R.R.

1957-09-17

A process is described wherein an anionic exchange technique is employed to separate uramium from a large variety of impurities. Very efficient and economical purification of contamimated uranium can be achieved by treatment of the contaminated uranium to produce a solution containing a high concentration of chloride. Under these conditions the uranium exists as an aniomic chloride complex. Then the uranium chloride complex is adsorbed from the solution on an aniomic exchange resin, whereby a portion of the impurities remain in the solution and others are retained with the uramium by the resin. The adsorbed impurities are then removed by washing the resin with pure concentrated hydrochloric acid, after which operation the uranium is eluted with pure water yielding an acidic uranyl chloride solution of high purity.

Lanthanide-halide based humidity indicators

DOEpatents

Beitz, James V [Hinsdale, IL; Williams, Clayton W [Chicago, IL

2008-01-01

The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.

Response surface methodology approach for the optimisation of adsorption of hydrolysed polyacrylamide from polymer-flooding wastewater onto steel slag: a good option of waste mitigation.

PubMed

Zhu, Mijia; Yao, Jun; Qin, Zhonghai; Lian, Luning; Zhang, Chi

2017-08-01

Wastewater produced from polymer flooding in oil production features high viscosity and chemical oxygen demand because of the residue of high-concentration polymer hydrolysed polyacrylamide (HPAM). In this study, steel slag, a waste from steel manufacturing, was studied as a low-cost adsorbent for HPAM in wastewater. Optimisation of HPAM adsorption by steel slag was performed with a central composite design under response surface methodology (RSM). Results showed that the maximum removal efficiency of 89.31% was obtained at an adsorbent dosage of 105.2 g/L, contact time of 95.4 min and pH of 5.6. These data were strongly correlated with the experimental values of the RSM model. Single and interactive effect analysis showed that HPAM removal efficiency increased with increasing adsorbent dosage and contact time. Efficiency increased when pH was increased from 2.6 to 5.6 and subsequently decreased from 5.6 to 9.3. It was observed that removal efficiency significantly increased (from 0% to 86.1%) at the initial stage (from 0 min to 60 min) and increased gradually after 60 min with an adsorbent dosage of 105.2 g/L, pH of 5.6. The adsorption kinetics was well correlated with the pseudo-second-order equation. Removal of HPAM from the studied water samples indicated that steel slag can be utilised for the pre-treatment of polymer-flooding wastewater.

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

PubMed

Saucier, Caroline; Adebayo, Matthew A; Lima, Eder C; Cataluña, Renato; Thue, Pascal S; Prola, Lizie D T; Puchana-Rosero, M J; Machado, Fernando M; Pavan, Flavio A; Dotto, G L

2015-05-30

Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10 min. The CSC-1.0 was acidified with a 6 mol L(-1) HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N2 adsorption/desorption curves, X-ray diffraction, and point of zero charge (pHpzc). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25 °C are 63.47 and 74.81 mg g(-1), respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations. Copyright © 2015 Elsevier B.V. All rights reserved.

Infrared and TPD studies of nitrates adsorbed on Tb{sub 4}O{sub 7}, La{sub 2}O{sub 3}, BaO, and MgO/{gamma}-Al{sub 2}O{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chi, Y.; Chuang, S.S.C.

2000-05-18

NO and O{sub 2} coadsorption on {gamma}-Al{sub 2}O{sub 3}-supported Tb{sub 4}O{sub 7}, La{sub 2}O{sub 3}, BaO, and MgO has been investigated by in situ infrared spectroscopy coupled with temperature-programmed decomposition and desorption. BaO/{gamma}-Al{sub 2}O{sub 3} and MgO/{gamma}-Al{sub 2}O{sub 3} possess a higher NO{sub x} storage capability than Tb{sub 4}O{sub 7}/{gamma}-Al{sub 2}O{sub 3} and La{sub 2}O{sub 3}/{gamma}-Al{sub 2}O{sub 3}. NO/O{sub 2} coadsorbed on Tb{sub 4}O{sub 7}, La{sub 2}O{sub 3}, and BaO in the form of bridging bidentate, chelating bidentate, and monodentate nitrates, and on MgO in the form of bridging bidentate and monodentate nitrates via the reaction of adsorbed NO withmore » adsorbed oxygen at 298 K. NO/O{sub 2} coadsorbed as a chelating bidentate nitrate on Tb{sub 4}O{sub 7} and La{sub 2}O{sub 3}, and as a distinctive bridging bidentate nitrate on BaO and MgO via the reaction of adsorbed NO with surface lattice oxygen at 523 K. These various forms of adsorbed nitrate differ in structure and reactivity from Tb(NO{sub 3}){sub 3}, La(NO{sub 3}){sub 3}, Ba(NO{sub 3}){sub 2}, and Mg(NO{sub 3}){sub 2}, the precursor used to prepare metal oxides for NO/O{sub 2} coadsorption. Temperature-programmed desorption (TPD) of chelating bidentate nitrate on Tb{sub 4}O{sub 7}, La{sub 2}O{sub 3}, and BaO produced primarily NO and O{sub 2}, with maxima at 640 and 670 K, respectively. TPD of bridging bidentate nitrate and monodentate nitrate on Tb{sub 4}O{sub 7}, La{sub 2}O{sub 3}, and BaO produced NO and O{sub 2} as major products and N{sub 2} and N{sub 2}O as minor products, at 320--500 K. Decomposition of bridging bidentate on MgO produced NO as a major product and N{sub 2}O as a minor product at a peak temperature of 690 K. Peak temperatures for Tb(NO{sub 3}){sub 3}, La(NO{sub 3}){sub 3}, Ba(NO{sub 3}){sub 2}, and Mg(NO{sub 3}){sub 2} decomposition occurred between those for bridging and chelating nitrates. The difference in stability between chelating and bridging bidentate nitrates on various metal oxides/{gamma}-Al{sub 2}O{sub 3} may provide a wide range of operating temperatures for NO{sub x} storage.« less

Cloning of a heavy-metal-binding protein derived from activated-sludge microorganisms.

PubMed

Sano, Daisuke; Myojo, Ken; Omura, Tatsuo

2006-09-01

A gene of the heavy-metal-binding protein (HMBP) was newly isolated from a genetic DNA library of activated-sludge microorganisms. HMBP was produced by transformed Escherichia coli, and the copper-binding ability of HMBP was confirmed. HMBP derived from activated sludge could be available as heavy metal adsorbents in water and wastewater treatments.

Development of a high performance (188)W/(188)Re generator by using a synthetic alumina.

PubMed

Lee, Jun Sig; Lee, Jong-Soup; Park, Ul-Jae; Son, Kwang-Jae; Han, Hyon-Soo

2009-01-01

A synthetic alumina functionalized with a sulfate moiety has been developed as the column material of (99)Mo/(99m)Tc and (188)W/(188)Re generators. This material is synthesized by a sol-gel processing. In order to characterize the adsorbent for the (188)W/(188)Re separation, both batch and column contact experiments were conducted. As a result of the experiments, it is found that the maximum capacity of the adsorbent for tungsten is higher than 450mg/g. Hence it is possible to produce approximately 3Ci (188)W/(188)Re generator with only 1g of the adsorbent from (188)W solutions supplied from ORNL, USA or RIAR, Russia. A demonstration study was conducted to show the performance of an (188)W/(188)Re generator column. In this study, 1Ci of (188)W purchased from RIAR, Russia, is loaded on a 0.9cm ID column packed with 0.7g of the adsorbent. Elution of (188)Re is performed every 4-7 days by using the saline solution for more than three months. Nearly 100% of tungsten is loaded by passing 5ml of the (188)W solution (pH=8) through the dry packed column at a 1ml/min flow rate. Elution efficiency of (188)Re is 70-90% by using 5ml of the saline solution. The ratio of (188)W/(188)Re in the eluted solution is 0.002-0.003%. When a Sep-Pak containing 0.26g of acid alumina is installed as a tandem column, the ratio is decreased to less than 10(-3)%. Thin layer chromatography for the eluted (188)Re solution shows 100% radiochemical purity. Also, alumina content in the eluted solution shows less than 10ppm. Through this study, the performance of this adsorbent was successfully demonstrated. By using the developed adsorbent, minimization of the generator column and consequently the volume of eluant could be possible while maintaining the quality of (188)Re just as much as that available in the market.

Microcolumn studies of dye adsorption onto manganese oxides modified diatomite.

PubMed

Al-Ghouti, M A; Khraisheh, M A M; Ahmad, M N; Allen, S J

2007-07-19

The method described here cannot fully replace the analysis of large columns by small test columns (microcolumns). The procedure, however, is suitable for speeding up the determination of adsorption parameters of dye onto the adsorbent and for speeding up the initial screening of a large adsorbent collection that can be tedious if a several adsorbents and adsorption conditions must be tested. The performance of methylene blue (MB), a basic dye, Cibacron reactive black (RB) and Cibacron reactive yellow (RY) was predicted in this way and the influence of initial dye concentration and other adsorption conditions on the adsorption behaviour were demonstrated. On the basis of the experimental results, it can be concluded that the adsorption of RY onto manganese oxides modified diatomite (MOMD) exhibited a characteristic "S" shape and can be simulated effectively by the Thomas model. It is shown that the adsorption capacity increased as the initial dye concentration increased. The increase in the dye uptake capacity with the increase of the adsorbent mass in the column was due to the increase in the surface area of adsorbent, which provided more binding sites for the adsorption. It is shown that the use of high flow rates reduced the time that RY in the solution is in contact with the MOMD, thus allowing less time for adsorption to occur, leading to an early breakthrough of RY. A rapid decrease in the column adsorption capacity with an increase in particle size with an average 56% reduction in capacity resulting from an increase in the particle size from 106-250 microm to 250-500 microm. The experimental data correlated well with calculated data using the Thomas equation and the bed depth-service time (BDST) equation. Therefore, it might be concluded that the Thomas equation and the BDST equations can produce accurate predication for variation of dye concentration, mass of the adsorbent, flow rate and particle size. In general, the values of adsorption isotherm capacity obtained in a batch system show the maximum values and are considerably higher than those obtained in a fixed-bed.

Organs-on-a-chip: a focus on compartmentalized microdevices.

PubMed

Moraes, Christopher; Mehta, Geeta; Lesher-Perez, Sasha Cai; Takayama, Shuichi

2012-06-01

Advances in microengineering technologies have enabled a variety of insights into biomedical sciences that would not have been possible with conventional techniques. Engineering microenvironments that simulate in vivo organ systems may provide critical insight into the cellular basis for pathophysiologies, development, and homeostasis in various organs, while curtailing the high experimental costs and complexities associated with in vivo studies. In this article, we aim to survey recent attempts to extend tissue-engineered platforms toward simulating organ structure and function, and discuss the various approaches and technologies utilized in these systems. We specifically focus on microtechnologies that exploit phenomena associated with compartmentalization to create model culture systems that better represent the in vivo organ microenvironment.

Sensing interactions in the microworld with optical tweezers

NASA Astrophysics Data System (ADS)

Pacoret, Cécile; Bowman, Richard; Gibson, Graham; Sinan, Haliyo D.; Bergander, Arvid; Carberry, David; Régnier, Stéphane; Padgett, Miles

2009-08-01

Optical Tweezers have become a widespread tool in Cell Biology, microengineering and other fields requiring delicate micromanipulation. But for those sensitive tasks, it remains difficult to handle objects without damaging them. As the precision in position and force measurement increase, the richness of information cannot be fully exploited with simple interfaces such as a mouse or a common joystick. For this reason, we propose a haptic force-feedback optical tweezer command and a force-feedback system controlled by one hand. The system combines accurate force measurement using a fast camera and the coupling of these measured forces with a human operator. The overall transparency allows even the feeling of the Brownian motion.

Adsorption affinity and selectivity of 3-ureidopropyltriethoxysilane grafted oil palm empty fruit bunches towards mercury ions.

PubMed

Kunjirama, Magendran; Saman, Norasikin; Johari, Khairiraihanna; Song, Shiow-Tien; Kong, Helen; Cheu, Siew-Chin; Lye, Jimmy Wei Ping; Mat, Hanapi

2017-06-01

This study was conducted to investigate the potential application of oil palm empty fruit branches (OPEFB) as adsorbents to remove organic methylmercurry, MeHg(II), and inorganic Hg(II) from aqueous solution. The OPEFB was functionalized with amine containing ligand namely 3-ureidopropyltriethoxysilane (UPTES) aiming for better adsorption performance towards both mercury ions. The adsorption was found to be dependent on initial pH, initial concentraton, temperatures, and contact time. The maximum adsorption capacities (Q m.exp ) of Hg(II) adsorption onto OPEFB and UPTES-OPEFB were 0.226 and 0.773 mmol/g, respectively. The Q m.exp of MeHg(II) onto OPEFB, however, was higher than UPTES-OPEFB. The adsorption kinetic data obeyed the Elovich model and the adsorption was controlled by the film-diffusion step. The calculated thermodynamic parameters indicate an endothermic adsorption process. Adsorption data analysis indicates that the adsorption mechanism may include ion-exchange, complexation, and physisorption interactions. The potential applications of adsorbents were demonstrated using oilfield produced water and natural gas condensate. The UPTES-OPEFB offered higher selectivity towards both mercury ions than OPEFB. The regenerability studies indicated that the adsorbent could be reused for multiple cycles.

Immunopotentiating reconstituted influenza virus virosome vaccine delivery system for immunization against hepatitis A.

PubMed Central

Glück, R; Mischler, R; Brantschen, S; Just, M; Althaus, B; Cryz, S J

1992-01-01

Hepatitis A virus (HAV) was purified from MRC-5 human diploid cell cultures, inactivated with formalin, and evaluated for safety and immunogenicity in humans. Three vaccine formulations were produced: (a) a fluid preparation containing inactivated HAV, (b) inactivated HAV adsorbed to Al(OH)3, and (c) inactivated HAV coupled to novel immunopotentiating reconstituted influenza virosomes (IRIV). IRIV were prepared by combining phosphatidylcholine, phosphatidylethanolamine, phospholipids originating from the influenza virus envelope, influenza virus hemagglutinin, and neuraminidase. The HAV-IRIV appeared as unilamellar vesicles with a diameter of approximately 150 nm when viewed by transmission electron microscopy. Upon intramuscular injection, the alum-adsorbed vaccine was associated with significantly (P < 0.01) more local adverse reactions than either the fluid or IRIV formulations. 14 d after a single dose of vaccine, all the recipients of the IRIV formulation seroconverted (> or = 20 mIU/ml) versus 30 and 44% for those who received the fluid and alum-adsorbed vaccines, respectively (P < 0.001). The geometric mean anti-HAV antibody titer achieved after immunization with the IRIV-HAV vaccine was also significantly higher (P < 0.005) compared with the other two vaccines. Images PMID:1334977

Oxidation of MnO(100) and NaMnO2 formation: Characterization of Mn2+ and Mn3+ surfaces via XPS and water TPD

NASA Astrophysics Data System (ADS)

Feng, Xu; Cox, David F.

2018-09-01

The oxidation of clean and Na precovered MnO(100) has been investigated by X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and temperature programmed desorption (TPD) of adsorbed water. XPS results indicate that Mn3O4-like and Mn2O3-like surfaces can be formed by various oxidation treatments of clean and nearly-stoichiometric MnO(100), while a NaMnO2-like surface can be produced by the oxidation of MnO(100) pre-covered with multilayers of metallic Na. Water TPD results indicate that water adsorption/desorption is sensitive to the available oxidation states of surface Mn cations, and can be used to distinguish between surfaces exposing Mn2+and Mn3+ cations, or a combination of these oxidation states. Carbon dioxide and water TPD results from the NaMnO2-like surface indicate that pre-adsorbed water blocks the uptake of CO2, while water displaces pre-adsorbed CO2. No indication of a strong reactive interaction is observed between CO2, water and the NaMnO2-like surface under the conditions of our study.

Practical performance and its efficiency of arsenic removal from groundwater using Fe-Mn binary oxide.

PubMed

Chang, Fangfang; Qu, Jiuhui; Liu, Ruiping; Zhao, Xu; Lei, Pengju

2010-01-01

A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite (FMBO(1:1)-diatomite) was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-treatment. The raw anaerobic groundwater containing 35-45 microg/L of arsenic was collected from suburb of Beijing. Arsenic (III) constituted roughly 60%-80% of the total arsenic content. Approximately 7,000 bed volumes (ratio of effluent volume to adsorbent volume) treated water with arsenic concentration below 10 microg/L were produced in the operation period of four months. The regeneration of FMBO (1:1)-diatomite had been operated for 15 times. In the first stage, the regeneration process significantly improved the adsorption capacity of FMBO (1:1)-diatomite. With increased loading amount of Fe-Mn binary oxide, the adsorption capacity for arsenic decreased 20%-40%. Iron and manganese in anaerobic groundwater were oxidized and adsorptive filtrated by FMBO (1:1)-diatomite efficiently. The final concentrations of iron and manganese in effluents were nearly zero. The continued safe performance of the treatment units proved that adsorbent FMBO (1:1)-diatomite had high oxidation ability and exhibited strong adsorptive filtration.

Production and optimization of bamboo hydrochars for adsorption of Congo red and 2-naphthol.

PubMed

Li, Yin; Meas, Arun; Shan, Shengdao; Yang, Ruiqin; Gai, Xikun

2016-05-01

Twelve hydrochars were produced from bamboo sawdust for adsorption of Congo red and 2-naphthol. The bamboo hydrochars have Brunauer-Emmett-Teller (BET) surface areas ranging from 2.63m(2)/g to 43.07m(2)/g, average pore diameters from 3.05nm to 3.83nm, pore volumes between 0.02cm(3)/g and 0.53cm(3)/g, and the surfaces of the hydrochars have diverse functional groups. The physico-chemical properties of the hydrochars critically depend on the hydrothermal conditions. All the hydrochars can adsorb Congo red and 2-naphthol from aqueous solutions, the largest adsorption capacity for Congo red is 33.7mg/g at the equilibrium concentration of 0.1mg/mL at 25°C, and the highest adsorption amount for 2-naphthol is 12.2mg/g at 25°C and 0.1mg/mL. Freundlich model can describe the adsorption isotherms of the both adsorbates slightly better than Langmuir model. These results provide a reference to the production and use of hydrochars as potential adsorbents in wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption

DOEpatents

Ghate, M.R.; Yang, R.T.

1985-10-03

Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high purity hydrogen from gaseous products of coal gasification and as an acid gas scrubber. 2 figs., 2 tabs.

Marine carbohydrates of wastewater treatment.

PubMed

Sudha, Prasad N; Gomathi, Thandapani; Vinodhini, P Angelin; Nasreen, K

2014-01-01

Our natural heritage (rivers, seas, and oceans) has been exploited, mistreated, and contaminated because of industrialization, globalization, population growth, urbanization with increased wealth, and more extravagant lifestyles. The scenario gets worse when the effluents or contaminants are discharged directly. So wastewater treatment is a very important and necessary in nowadays to purify wastewater before it enters a body of natural water, or it is applied to the land, or it is reused. Various methods are available for treating wastewater but with many disadvantages. Recently, numerous approaches have been studied for the development of cheaper and more effective technologies, both to decrease the amount of wastewater produced and to improve the quality of the treated effluent. Biosorption is an emerging technology, which uses natural materials as adsorbents for wastewater treatment. Low-cost adsorbents of polysaccharide-based materials obtained from marine, such as chitin, chitosan, alginate, agar, and carrageenan, are acting as rescue for wastewater treatment. This chapter reviews the treatment of wastewater up to the present time using marine polysaccharides and its derivatives. Special attention is paid to the advantages of the natural adsorbents, which are a wonderful gift for human survival. © 2014 Elsevier Inc. All rights reserved.

Performance Evaluation of the ISS Water Processor Multifiltration Beds

NASA Technical Reports Server (NTRS)

Bowman, Elizabeth M.; Carter, Layne; Wilson, Mark; Cole, Harold; Orozco, Nicole; Snowdon, Doug

2012-01-01

The ISS Water Processor Assembly (WPA) produces potable water from a waste stream containing humidity condensate and urine distillate. The primary treatment process is achieved in the Multifiltration Bed, which includes adsorbent media and ion exchange resin for the removal of dissolved organic and inorganic contaminants. The first Multifiltration Bed was replaced on ISS in July 2010 after initial indication of inorganic breakthrough. This bed was returned to ground in July 2011 for an engineering investigation. The water resident in the bed was analyzed for various parameters to evaluate adsorbent loading, performance of the ion exchange resin, microbial activity, and generation of leachates from the ion exchange resin. Portions of the adsorbent media and ion exchange resin were sampled and subsequently desorbed to identify the primary contaminants removed at various points in the bed. In addition, an unused Multifiltration Bed was evaluated after two years in storage to assess the generation of leachates during storage. This assessment was performed to evaluate the possibility that these leachates are impacting performance of the Catalytic Reactor located downstream of the Multifiltration Bed. The results of these investigations and implications to the operation of the WPA on ISS are documented in this paper.

Chemistry of CCl 4 on Fe 3O 4(1 1 1)-(2 × 2) surfaces in the presence of adsorbed D 2O studied by temperature programmed desorption

NASA Astrophysics Data System (ADS)

Adib, K.; Totir, G. G.; Fitts, J. P.; Rim, K. T.; Mueller, T.; Flynn, G. W.; Joyce, S. A.; Osgood, R. M.

2003-07-01

Temperature programmed desorption (TPD) was used to study surface reactions of Fe 3O 4(1 1 1)-(2 × 2) sequentially exposed, at ˜100 K, to vapor-phase D 2O and CCl 4. Previous TPD and XPS results have indicated that in the absence of D 2O, CCl 4 dissociatively adsorbs on Fe 3O 4(1 1 1) producing chemisorbed Cl and CCl 2. Subsequent heating of the surface results in abstraction of lattice iron and oxygen atoms and causes them to desorb as FeCl 2 and OCCl 2, respectively. This study shows that when this Fe 3O 4 surface is exposed only to D 2O, TPD measures a rich surface chemistry with multiple desorption events extending as high as ˜800 K, indicating dissociative adsorption of D 2O on the Fe 3O 4(1 1 1) surface. After sequential exposure to D 2O and then CCl 4, the production of FeCl 2 and OCCl 2 from adsorbed CCl 4 is suppressed, indicating that D 2O fragments block the surface reactive sites.

Twisting microfluidics in a planetary centrifuge.

PubMed

Yasuda, Shoya; Hayakawa, Masayuki; Onoe, Hiroaki; Takinoue, Masahiro

2017-03-15

This paper reports a twisting microfluidic method utilising a centrifuge-based fluid extruding system in a planetary centrifuge which simultaneously generates an orbital rotation and an axial spin. In this method, fluid extrusion from a micro-scale capillary to an 'open-space' solution or air enables release of the fluid from the capillary-based microchannel, which physically means that there is a release of fluids from a confined low-Reynolds-number environment to an open non-low-Reynolds-number environment. As a result, the extruded fluids are separated from the axial spin of the capillary, and the difference in the angular rates of the axial spin between the capillary and the extruded fluids produces the 'twisting' of the fluid. In this study, we achieve control of the twist of highly viscous fluids, and we construct a simple physical model for the fluid twist. In addition, we demonstrate the formation of twisted hydrogel microstructures (stripe-patterned microbeads and multi-helical microfibres) with control over the stripe pattern and the helical pitch length. We believe that this method will enable the generation of more sophisticated microstructures which cannot easily be formed by usual channel-based microfluidic devices. This method can also provide advanced control of microfluids, as in the case of rapid mixing of highly viscous fluids. This method can contribute to a wide range of applications in materials science, biophysics, biomedical science, and microengineering in the future.

Designing 3-Dimensional In Vitro Oviduct Culture Systems to Study Mammalian Fertilization and Embryo Production.

PubMed

Ferraz, Marcia A M M; Henning, Heiko H W; Stout, Tom A E; Vos, Peter L A M; Gadella, Bart M

2017-07-01

The oviduct was long considered a largely passive conduit for gametes and embryos. However, an increasing number of studies into oviduct physiology have demonstrated that it specifically and significantly influences gamete interaction, fertilization and early embryo development. While oviduct epithelial cell (OEC) function has been examined during maintenance in conventional tissue culture dishes, cells seeded into these two-dimensional (2-D) conditions suffer a rapid loss of differentiated OEC characteristics, such as ciliation and secretory activity. Recently, three-dimensional (3-D) cell culture systems have been developed that make use of cell inserts to create basolateral and apical medium compartments with a confluent epithelial cell layer at the interface. Using such 3-D culture systems, OECs can be triggered to redevelop typical differentiated cell properties and levels of tissue organization can be developed that are not possible in a 2-D culture. 3-D culture systems can be further refined using new micro-engineering techniques (including microfluidics and 3-D printing) which can be used to produce 'organs-on-chips', i.e. live 3-D cultures that bio-mimic the oviduct. In this review, concepts for designing bio-mimic 3-D oviduct cultures are presented. The increased possibilities and concomitant challenges when trying to more closely investigate oviduct physiology, gamete activation, fertilization and embryo production are discussed.

Arsenic sorption by red mud-modified biochar produced from rice straw.

PubMed

Wu, Chuan; Huang, Liu; Xue, Sheng-Guo; Huang, Yu-Ying; Hartley, William; Cui, Meng-Qian; Wong, Ming-Hung

2017-08-01

Red mud-modified biochar (RM-BC) has been produced to be utilized as a novel adsorbent to remove As because it can effectively combine the beneficial features of red mud (rich metal oxide composition and porous structure) and biochar (large surface area and porous structure properties). SEM-EDS and XRD analyses demonstrated that red mud had loaded successfully on the surface of biochar. With the increasing of pH in solution, arsenate (As(V)) adsorption on RM-BC decreased while arsenite (As(III)) increased. Arsenate adsorption kinetics process on RM-BC fitted the pseudo-second-order model, while that of As(III) favored the Elovich model. All sorption isotherms produced superior fits with the Langmuir model. RM-BC exhibited improved As removal capabilities, with a maximum adsorption capacity (Q max ) for As(V) of 5923 μg g -1 , approximately ten times greater than that of the untreated BC (552.0 μg g -1 ). Furthermore, it has been indicated that the adsorption of As(V) on RM-BC may be strongly associated with iron oxides (hematite and magnetite) and aluminum oxides (gibbsite) by X-ray absorption near-edge spectroscopy (XANES), which was possibly because of surface complexation and electrostatic interactions. RM-BC may be used as a valuable adsorbent for removing As in the environment due to the waste materials being relatively abundant.

Activated carbon from biomass

NASA Astrophysics Data System (ADS)

Manocha, S.; Manocha, L. M.; Joshi, Parth; Patel, Bhavesh; Dangi, Gaurav; Verma, Narendra

2013-06-01

Activated carbon are unique and versatile adsorbents having extended surface area, micro porous structure, universal adsorption effect, high adsorption capacity and high degree of surface reactivity. Activated carbons are synthesized from variety of materials. Most commonly used on a commercial scale are cellulosic based precursors such as peat, coal, lignite wood and coconut shell. Variation occurs in precursors in terms of structure and carbon content. Coir having very low bulk density and porous structure is found to be one of the valuable raw materials for the production of highly porous activated carbon and other important factor is its high carbon content. Exploration of good low cost and non conventional adsorbent may contribute to the sustainability of the environment and offer promising benefits for the commercial purpose in future. Carbonization of biomass was carried out in a horizontal muffle furnace. Both carbonization and activation were performed in inert nitrogen atmosphere in one step to enhance the surface area and to develop interconnecting porosity. The types of biomass as well as the activation conditions determine the properties and the yield of activated carbon. Activated carbon produced from biomass is cost effective as it is easily available as a waste biomass. Activated carbon produced by combination of chemical and physical activation has higher surface area of 2442 m2/gm compared to that produced by physical activation (1365 m2/gm).

Study of gas adsorption on as-produced and modified carbon nanotubes

NASA Astrophysics Data System (ADS)

Rawat, Dinesh Singh

Volumetric adsorption isotherm measurements were used to study the adsorption characteristics of Ethane (C2H6) and Butane (C 4H10) on as-produced single-walled carbon nanotubes. The binding energy of the adsorbed alkane molecule was found to increase with increasing carbon chain length. Two adsorption substeps were obtained for each alkane molecule. However, the size of the high pressure substep was found to be gradually smearing with the increase in size of the adsorbed molecule. This phenomenon is interpreted as size entropy effect for linear molecules. This interpretation was also verified by determining the specific surface area of the substrate using linear molecules of different sizes. Kinetics measurements of alkane adsorption on SWNTs were also conducted and their dependence on the molecular length was determined. Similar adsorption measurements were performed for Argon (Ar) on as-produced single-walled carbon nanotubes and nanotubes that were structurally modified using acid treatment. Enhancement of the sorptive capacity and the presence of two distinct kinetics of gas adsorption verified partial opening of single walled carbon nanotubes as a result of chemical treatment. Mutiwalled carbon nanotubes were exposed to oxygen plasma treatment for varying time periods. Afterwards, adsorption measurements of Methane (CH 4) were conducted on untreated and oxygen plasma treated tubes. The presence of an additional substep, after exposing multiwalled carbon nanotubes to oxygen plasma for varying time periods, suggested progressive cleaning of nanotube surface.

Adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II), and As(V) on bacterially produced metal sulfides.

PubMed

Jong, Tony; Parry, David L

2004-07-01

The adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II) and As(V) onto bacterially produced metal sulfide (BPMS) material was investigated using a batch equilibrium method. It was found that the sulfide material had adsorptive properties comparable with those of other adsorbents with respect to the specific uptake of a range of metals and, the levels to which dissolved metal concentrations in solution can be reduced. The percentage of adsorption increased with increasing pH and adsorbent dose, but decreased with increasing initial dissolved metal concentration. The pH of the solution was the most important parameter controlling adsorption of Cd(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), and As(V) by BPMS. The adsorption data were successfully modeled using the Langmuir adsorption isotherm. Desorption experiments showed that the reversibility of adsorption was low, suggesting high-affinity adsorption governed by chemisorption. The mechanism of adsorption for the divalent metals was thought to be the formation of strong, inner-sphere complexes involving surface hydroxyl groups. However, the mechanism for the adsorption of As(V) by BPMS appears to be distinct from that of surface hydroxyl exchange. These results have important implications to the management of metal sulfide sludge produced by bacterial sulfate reduction.

Application of ultradisperse magnetic adsorbents for removal of small concentrations of pollutants from large volumes of water

NASA Astrophysics Data System (ADS)

Nechitailo, Galina S.; Kuznetsov, Anatoli; Kuznetsov, Oleg

2016-07-01

Pollution of natural bodies of water (rivers, lakes, ground water, etc) is unfortunately very common, both from natural sources like volcanic activity; and, even more importantly, from human activity, including disposal of industrial and municipal waste, mining, etc. Many toxic substances are harmful for humans and other organisms even in very low concentrations (e.g., less than 1 µg/L of cadmium is harmful, for Hg it is 0.5 µg/L, for phenol - 1 µg/L), and can remain in water for decades or longer. Cleaning large volumes of water even from low concentrations of pollutants is a challenging technological task and is very expensive. We propose to use suspension of ultradisperse magnetic adsorbents, for example, nanostructured ferro-carbon particles, produced by plasmachemical technique, for removing small concentrations of pollutants from large volumes of water. The suspension is introduced into the water. Due to their small sizes and densities similar to water (we measured the density of FC-4 ferro-carbon to be about 1 g/cm3; presumably due to porosity) the particles do not sediment for a long time (hours, days or longer), move due to Brownian motion and adsorb a variety of substances from the water. The particle surface can be modified to provide selectivity of the adsorption. Sorption capacities of ferro-carbon adsorbents is in dozens of percent. Therefore, to collect 1 kg of a pollutant, 2 to 20 kg of the adsorbents is required. Then the particles with the adsorbed contaminant can be collected (e.g., downstream of the river) using a variety of magnetic traps. The traps can consist of ferromagnetic wires and permanent magnets, a variety of simple and inexpensive designs are available. As a model system, the kinetics of adsorption of a highly diluted (0.002 mg/ml) aqueous solution of a low molecular weight compound (toluidine blue) by a small concentration of a ferro-carbon powder (FC-4) was studied by spectrophotometry. Before each measurement, the particles with the adsorbed toluidine blue were removed from the solution by magnetic separation. The sorbent was proven to have high sorption capacity and rapid adsorption kinetics for toluidine blue. These experiments demonstrated the validity of the method, where a small concentration of a pollutant was successfully collected from a large volume of water. By varying the ratio of the sorbent/pollutant, it is possible to optimize the sorbent use and the time required to adsorb all pollutant present in the treated water. A variety of magnetically controlled sorbents can be designed and used in this method, from broad-spectrum adsorbing sorbents to sorbents specifically targeting a particular pollutant. These sorbents can be used either individually or as mixtures of sorbents with different properties, depending on the desired purification goals. Simplicity and scalability of this method allow a variety of ecological applications, as well as industrial ones, from process water purification to wastewater treatment.

Rotary adsorbers for continuous bulk separations

DOEpatents

Baker, Frederick S [Oak Ridge, TN

2011-11-08

A rotary adsorber for continuous bulk separations is disclosed. The rotary adsorber includes an adsorption zone in fluid communication with an influent adsorption fluid stream, and a desorption zone in fluid communication with a desorption fluid stream. The fluid streams may be gas streams or liquid streams. The rotary adsorber includes one or more adsorption blocks including adsorbent structure(s). The adsorbent structure adsorbs the target species that is to be separated from the influent fluid stream. The apparatus includes a rotary wheel for moving each adsorption block through the adsorption zone and the desorption zone. A desorption circuit passes an electrical current through the adsorbent structure in the desorption zone to desorb the species from the adsorbent structure. The adsorbent structure may include porous activated carbon fibers aligned with their longitudinal axis essentially parallel to the flow direction of the desorption fluid stream. The adsorbent structure may be an inherently electrically-conductive honeycomb structure.

Activated carbon prepared from yerba mate used as a novel adsorbent for removal of tannery dye from aqueous solution.

PubMed

Linhares, Bruno; Weber, Caroline Trevisan; Foletto, Edson Luiz; Paz, Diego Silva; Mazutti, Marcio A; Collazzo, Gabriela Carvalho

2013-01-01

Activated carbon prepared from yerba mate (Ilex paraguariensis) was used as adsorbent for the removal of tannery dye from aqueous solution. The activated carbon was characterized, and it showed a mesoporous texture, with surface area of 537.4 m2 g(-1). The initial dye concentration, contact time and pH influenced the adsorption capacity. The equilibrium data were in good agreement with both Langmuir and Freundlich isotherms. The adsorption kinetics of the tannery dye on activated carbon prepared from yerba mate followed a pseudo-second-order model. The adsorption process was found to be controlled by both external mass-transfer and intraparticle diffusion, but the external diffusion was the dominating process. This work highlights the potential application of activated carbon produced from yerba mate in the field of adsorption.

Adsorption characteristics of water vapor on gear-pellet and honeycomb-pellet types of adsorbents containing A-type zeolite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, A.; Munakata, K.; Hara, K.

2015-03-15

It is necessary to recover or process tritiated species that are extensively coexistent in nuclear fusion installations. A conventional way to recover tritium release to atmosphere is catalytic oxidation of tritiated species and adsorption of tritiated water vapor on adsorbents with high surface areas. Therefore, new adsorbents with low pressure loss and high surface areas need to be developed and utilized for such large-scale adsorption systems. In this study, attention was focused on new adsorbents, which are gear-type pellet MS5A adsorbent, gear-type pellet MS4A adsorbent and honeycomb-type pellet MS5A adsorbent. The adsorption characteristics of the new adsorbent were comparatively studiedmore » with conventional type of adsorbents (pellet-type MS5A adsorbent and pebble-type MS5A adsorbent), in terms of adsorption capacity, pressure loss and adsorption rate. It was found that the adsorption capacity of water vapor on the gear-type adsorbents is higher than that on a honeycomb-type adsorbent. The experimental breakthrough curves indicate that the adsorption rates of water vapor on gear-type and honeycomb-type adsorbents are smaller than that on conventional type adsorbents. Various adsorption models were also tested to correlate the experimental isotherms. It was found that the Langmuir-Freundlich model could properly correlate the experimental adsorption isotherms.« less

Isotopic separation of D.sub.2 O from H.sub.2 O using ruthenium adsorbent

DOEpatents

Thiel, Patricia A.

1990-04-10

A method of enrichment of D.sub.2 O in solutions of D.sub.2 O in H.sub.2 O by contacting said solutions in the steam phase with hexagonal crystalline to produce enriched D.sub.2 O. The passages may be repeated to achieve a desired amount of D.sub.2 O.

Topologically guided tuning of Zr-MOF pore structures for highly selective separation of C6 alkane isomers

DOE PAGES

Wang, Hao; Dong, Xinglong; Lin, Junzhong; ...

2018-05-01

As an alternative technology to energy intensive distillations, adsorptive separation by porous solids offers lower energy cost and higher efficiency. Herein we report a topology-directed design and synthesis of a series of Zr-based metal-organic frameworks with optimized pore structure for efficient separation of C6 alkane isomers, a critical step in the petroleum refining process to produce gasoline with high octane rating. Zr 6O 4(OH) 4(bptc) 3 adsorbs a large amount of n-hexane but excluding branched isomers. The n-hexane uptake is ~70% higher than that of a benchmark adsorbent, zeolite-5A. A derivative structure, Zr 6O 4(OH) 8(H 2O) 4(abtc) 2, ismore » capable of discriminating all three C6 isomers and yielding a high separation factor for 3-methylpentane over 2,3-dimethylbutane. This property is critical for producing gasoline with further improved quality. Multicomponent breakthrough experiments provide a quantitative measure of the capability of these materials for separation of C6 alkane isomers. A detailed structural analysis reveals the unique topology, connectivity and relationship of these compounds.« less

Improving quality of textile wastewater with organic materials as multi soil layering

NASA Astrophysics Data System (ADS)

Supriyadi; Widijanto, H.; Pranoto; Dewi, AK

2016-02-01

On agricultural land, fresh water is needed especially for irrigation. Alternative ways to fulfill needs of fresh water is by utilizing wastewater from industry. Wastewater that produced in the industry in Surakarta is over flowing especially textile wastewater. Wastewater that produced from industry has many pollutants that affected decreasing fresh water quality for irrigation. Multi Soil Layering (MSL) is one of method that utilize the soil ability as main media by increasing its function of soil structure to purify wastewater, so it does not contaminate the environment and reusable. This research was purposed to know affectivity of organic materials (such as rice straw, baggase, sawdust, coconut fibre, and corncob) and dosage (5%, 10% and 25%) in MSL, also get alternative purification ways with easy and cheaper price as natural adsorbent. This study using field and laboratory experiment. The result shows that MSL can be an alternative method of purification of wastewater. The appropriate composition of organic materials that can be used as adsorbent is MSL with wood sawdust 10% dosage because it can increase pH, decrease the number of Cr, ammonia, and phosphate but less effective to decrease BOD and COD.

Hydrogen storage in graphite nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, C.; Tan, C.D.; Hidalgo, R.

1998-08-01

Graphite nanofibers (GNF) are a type of material that is produced by the decomposition of carbon containing gases over metal catalyst particles at temperatures around 600 C. These molecularly engineered structures consist of graphene sheets perfectly arranged in a parallel, perpendicular or at angle orientation with respect to the fiber axis. The most important feature of the material is that only edges are exposed. Such an arrangement imparts the material with unique properties for gas adsorption because the evenly separated layers constitute the most ordered set of nanopores that can accommodate an adsorbate in the most efficient manner. In addition,more » the non-rigid pore walls can also expand so as to accommodate hydrogen in a multilayer conformation. Of the many varieties of structures that can be produced the authors have discovered that when gram quantities of a selected number of GNF are exposed to hydrogen at pressures of {approximately} 2,000 psi, they are capable of adsorbing and storing up to 40 wt% of hydrogen. It is believed that a strong interaction is established between hydrogen and the delocalized p-electrons present in the graphite layers and therefore a new type of chemistry is occurring within these confined structures.« less

Topologically guided tuning of Zr-MOF pore structures for highly selective separation of C6 alkane isomers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hao; Dong, Xinglong; Lin, Junzhong

As an alternative technology to energy intensive distillations, adsorptive separation by porous solids offers lower energy cost and higher efficiency. Herein we report a topology-directed design and synthesis of a series of Zr-based metal-organic frameworks with optimized pore structure for efficient separation of C6 alkane isomers, a critical step in the petroleum refining process to produce gasoline with high octane rating. Zr 6O 4(OH) 4(bptc) 3 adsorbs a large amount of n-hexane but excluding branched isomers. The n-hexane uptake is ~70% higher than that of a benchmark adsorbent, zeolite-5A. A derivative structure, Zr 6O 4(OH) 8(H 2O) 4(abtc) 2, ismore » capable of discriminating all three C6 isomers and yielding a high separation factor for 3-methylpentane over 2,3-dimethylbutane. This property is critical for producing gasoline with further improved quality. Multicomponent breakthrough experiments provide a quantitative measure of the capability of these materials for separation of C6 alkane isomers. A detailed structural analysis reveals the unique topology, connectivity and relationship of these compounds.« less

EDITORIAL: The 18th European Workshop on Micromechanics (MME 07)

NASA Astrophysics Data System (ADS)

Correia, J. H.

2008-06-01

This special issue of Journal of Micromechanics and Microengineering is devoted to the 18th European Workshop on Micromechanics (MME 07), which took place at the University of Minho, Guimarães, Portugal from 16-18 September 2007. Since the first workshop at the University of Twente in 1989 the field of micromechanics has grown substantially and new fields have been added: optics, RF, biomedical, chemistry, and in recent years the emergence of nanotechnology. This year an extensive programme was scheduled with contributions from new materials research to new manufacturing techniques. In addition, the invited speakers presented a review of the state-of-the-art in several main trends in current research, with the focus on micro/nanosystems in the ICT Work Programme in EC FP7. As ever, the two day workshop was attended by delegates from all over Europe, the USA, Brazil, Egypt, Japan and Canada. A total of 96 papers were accepted for presentation and there were a further five keynote presentations. The workshop provides a forum for young researchers to learn about new experimental methods and to enhance their knowledge of the field. This special issue presents a selection of 17 of the best papers from the workshop. The papers highlight fluidic and optical devices, energy scavenging microsystems, neural probe arrays and microtechnology fabrication techniques. All the papers went through the regular reviewing procedure of IOP Publishing, and I am grateful to all the referees for their excellent work. I would also like to extend my thanks to Professor Robert Puers for advice on the final selection of papers and to Ian Forbes of IOP Publishing for managing the entire process. My thanks also go to the editorial staff of Journal of Micromechanics and Microengineering. I believe that this special issue will provide a good overview of the topics presented at the workshop and I hope you enjoy reading it.

Hybrid Filter Membrane

NASA Technical Reports Server (NTRS)

Laicer, Castro; Rasimick, Brian; Green, Zachary

2012-01-01

Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of dust particles on the filter surface and to facilitate dust removal with pulse or back airflow.

EDITORIAL: Selected papers from the 11th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2011) Selected papers from the 11th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2011)

NASA Astrophysics Data System (ADS)

Cho, Young-Ho

2012-09-01

This special section of Journal of Micromechanics and Microengineering features papers selected from the 11th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2011), held at Sejong Hotel in Seoul, Korea during 15-18 November 2011. Since the first PowerMEMS workshop held in Sendai, Japan in 2000, the workshop has developed as the premier forum for reporting research results in micro and nanotechnology for power generation, energy conversion, harvesting and processing applications, including in-depth technical issues on nanostructures and materials for small-scale high-density energy and thermal management. Potential PowerMEMS applications cover not only portable power devices for consumer electronics and remote sensors, but also micro engines, impulsive thrusters and fuel cells for systems ranging from the nanometer to the millimeter scale. The 2011 technical program consists of 1 plenary talk, 4 invited talks and 118 contributed presentations. The 48 oral and 70 poster presentations, selected by 27 Technical Program Committee Members from 131 submitted abstracts, have stimulated lively discussion maximizing the interaction between participants. Among them, this special section includes 9 papers covering micro-scale power generators, energy converters, harvesters, thrusters and thermal coolers. Finally, we are grateful to the members of the International Steering Committee, the Technical Program Committee, and the Local Organizing Committee for their efforts and contributions to PowerMEMS 2011. We also thank the two companies Samsung Electro-Mechanics and LG Elite for technical tour arrangements. Special thanks go to Dr Ian Forbes, the editorial staff of the Journal of Micromechanics and Microengineering, as well as to the staff of IOP Publishing for making this special section possible.

Electrical stimulation of microengineered skeletal muscle tissue: Effect of stimulus parameters on myotube contractility and maturation.

PubMed

Banan Sadeghian, Ramin; Ebrahimi, Majid; Salehi, Sahar

2018-04-01

Skeletal muscle tissues engineered in vitro are aneural, are short in the number of fibres required to function properly and degenerate rapidly. Electrical stimulation has been widely used to compensate for such a lack of neural activity, yet the relationship between the stimulation parameters and the tissue response is subject to debate. Here we studied the effect of overnight electrical stimulation (training) on the contractility and maturity of aligned C2C12 myotubes developed on micropatterned gelatin methacryloyl (GelMA) substrates. Bipolar rectangular pulse (BRP) trains with frequency, half-duration and applied pulse train amplitudes of f = 1 Hz, t on  = 0.5 ms and V app  = {3 V, 4 V, 4.5 V}, respectively, were applied for 12 h to the myotubes formed on the microgrooved substrates. Aligned myotubes were contracting throughout the training period for V app  ≥ 4 V. Immediately after training, the samples were subjected to series of BRPs with 2 ≤ V app  ≤ 5 V and 0.2 ≤ t on  ≤ 0.9 ms, during which myotube contraction dynamics were recorded. Analysis of post-training contraction revealed that only the myotubes trained at V app  = 4 V displayed consistent and repeatable contraction profiles, showing the dynamics of myotube contractility as a function of triggering pulse voltage and current amplitudes, duration and imposed electrical energy. In addition, myotubes trained at V app  = 4 V displayed amplified expression levels of genes pertinent to sarcomere development correlated with myotube maturation. Our findings are imperative for a better understanding of the influence of electrical pulses on the maturation of microengineered myotubes. Copyright © 2017 John Wiley & Sons, Ltd.

Potential of coconut shell activated carbon (CSAC) in removing contaminants for water quality improvement: A critical review

NASA Astrophysics Data System (ADS)

Akhir, Muhammad Fitri Mohd; Saad, Noor Aida; Zakaria, Nor Azazi

2017-10-01

Commonly, water contaminations occur due to human-induced conditions such as industrial discharge and urban activities. The widely identified contaminants are heavy metal. The toxicity of those heavy metal elements is high and very poisonous to humans' health and environment even at lower dose or concentration of exposure. Chronic poisoning can cause fatal or defect to one's body or environment. Organic contaminants such as oil and microbial are also found due to decomposition of organic matter. The excellent quality adsorption of contaminants is highly related to surface area, pore size, pore volume, and amount plus type of functional group on surface of CSAC. The higher the surface area and pore volume, the higher adsorption that CSAC have towards contaminants. In comparison to meso-pore and macro-pore, micro-pore is better for trapping and adsorbing water contaminants. The purpose of this article is to critically review the potential of CSAC in increasing adsorption to remove contaminants for water quality improvement. A critical review is implemented using search engine like Science Direct. Alkali-modification is shown to have good adsorption in anion elements and organic matter due to improvement of hydrophobic organic compound (HOC) while acid-modification is good in cation elements adsorption. Strong alkali impregnated solution makes CSAC more hydrophobic and positively charge especially after increasing the impregnation dosage. Strong acid of adsorbate affects the quality of adsorption by reducing the surface area, pore volume and it also breaks the Van der Waals forces between adsorbent and adsorbate. However, the formation of oxygen helps the activated carbon surface to become more hydrophilic and negative charge is produced. It helps the effectiveness of metal adsorption. Therefore, by controlling dosage and types of functional groups on surface of CSAC and the pH of adsorbate, it can contribute to high adsorption of organic and inorganic contaminants in the water.

CFD Modelling of Adsorption Behaviour in AGN Tank with Polyethylene Terephthalate Plastic Waste Based Activated Carbon

NASA Astrophysics Data System (ADS)

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

2018-03-01

Indonesia imports fuel (fuel oil) in large quantities. Indonesia has reserves of methane gas in the form of natural gas in large numbers but has obstacles in the process of storage. To produce a storage tank to a safe condition then proclaimed to use ANG (Adsorbed Natural Gas) technology. Manufacture of activated PET based activated carbon for storage of natural gas where technology has been widely studied, but still has some shortcomings. Therefore to predict the performance of ANG technology, modeling of ANG tank with Fluent CFD program is done so the condition inside the ANG tank can be known and can be used to increased the performance of ANG technology. Therefore, in this experiment natural gas storage test is done at the ANG tank model using Fluent CFD program. This experiment is begin with preparation tools and material by characterize the natural gas and activated carbon followed by create the mesh and model of ANG tank. The next process is state the characteristic of activated carbon and fluid in this experiment. The last process is run the simulation using the condition that already been stated which is at 27°C and 35 bar during 15 minutes. The result is at adsorption contour we can see that adsorption is higher at the top of the tank because the input of the adsorbent is at the top of the ANG tank so the adsorbate distribution is uneven that cause the adsorbate concentration at the top of the ANG tank is higher than the bottom tank.

Biochar enhances Aspergillus niger rock phosphate solubilization by increasing organic acid production and alleviating fluoride toxicity.

PubMed

Mendes, Gilberto de Oliveira; Zafra, David Lopez; Vassilev, Nikolay Bojkov; Silva, Ivo Ribeiro; Ribeiro, José Ivo; Costa, Maurício Dutra

2014-05-01

During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F(-)) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F(-) adsorbents [activated alumina (Al2O3) and biochar] on RP solubilization by Aspergillus niger was examined. Al2O3 adsorbed part of the F(-) released but also adsorbed soluble P, which makes it inappropriate for microbial RP solubilization systems. In contrast, biochar adsorbed only F(-) while enhancing phosphate solubilization 3-fold, leading to the accumulation of up to 160 mg of P per liter. By comparing the values of F(-) measured in solution at the end of incubation and those from a predictive model, it was estimated that up to 19 mg of F(-) per liter can be removed from solution by biochar when added at 3 g liter(-1) to the culture medium. Thus, biochar acted as an F(-) sink during RP solubilization and led to an F(-) concentration in solution that was less inhibitory to the process. In the presence of biochar, A. niger produced larger amounts of citric, gluconic, and oxalic acids, whether RP was present or not. Our results show that biochar enhances RP solubilization through two interrelated processes: partial removal of the released F(-) and increased organic acid production. Given the importance of organic acids for P solubilization and that most of the RPs contain high concentrations of F(-), the proposed solubilization system offers an important technological improvement for the microbial production of soluble P fertilizers from RP.

Adsorption of Rare Earths(Ⅲ) Using an Efficient Sodium Alginate Hydrogel Cross-Linked with Poly-γ-Glutamate

PubMed Central

Xu, Shuxia; Wang, Zhiwei; Gao, Yuqian; Zhang, Shimin; Wu, Kun

2015-01-01

With the exploitation of rare earth ore, more and more REEs came into groundwater. This was a waste of resources and could be harmful to the organisms. This study aimed to find an efficient adsorption material to mitigate the above issue. Through doping sodium alginate (SA) with poly-γ-glutamate (PGA), an immobilized gel particle material was produced. The composite exhibited excellent capacity for adsorbing rare earth elements (REEs). The amount of La3+ adsorbed on the SA-PGA gel particles reached approximately 163.93 mg/g compared to the 81.97 mg/g adsorbed on SA alone. The factors that potentially affected the adsorption efficiency of the SA-PGA composite, including the initial concentration of REEs, the adsorbent dosage, and the pH of the solution, were investigated. 15 types of REEs in single and mixed aqueous solutions were used to explore the selective adsorption of REEs on gel particles. Scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy analyses of the SA and SA-PGA gel beads suggested that the carboxyl groups in the composite might play a key role in the adsorption process and the morphology of SA-PGA changed from the compact structure of SA to a porous structure after doping PGA. The kinetics and thermodynamics of the adsorption of REEs were well fit with the pseudo-second-order equation and the Langmuir adsorption isotherm model, respectively. It appears that SA-PGA is useful for recycling REEs from wastewater. PMID:25996388

In situ STM imaging of the structures of pentacene molecules adsorbed on Au(111).

PubMed

Pong, Ifan; Yau, Shuehlin; Huang, Peng-Yi; Chen, Ming-Chou; Hu, Tarng-Shiang; Yang, Yawchia; Lee, Yuh-Lang

2009-09-01

In situ scanning tunneling microscope (STM) was used to examine the spatial structures of pentacene molecules adsorbed onto a Au(111) single-crystal electrode from a benzene dosing solution containing 16-400 microM pentacene. Molecular-resolution STM imaging conducted in 0.1 M HClO(4) revealed highly ordered pentacene structures of ( radical31 x radical31)R8.9 degrees , (3 x 10), ( radical31 x 10), and ( radical7 x 2 radical7)R19.1 degrees adsorbed on the reconstructed Au(111) electrode dosed with different pentacene solutions. These pentacene structures and the reconstructed Au(111) substrate were stable between 0.2 and 0.8 V [vs reversible hydrogen electrode, RHE]. Increasing the potential to E > 0.8 V lifted the reconstructed Au(111) surface and disrupted the ordered pentacene adlattices simultaneously. Ordered pentacene structures could be restored by applying potentials negative enough to reinforce the reconstructed Au(111). At potentials negative of 0.2 V, the adsorption of protons became increasingly important to displace adsorbed pentacene admolecules. Although the reconstructed Au(111) structure was not essential to produce ordered pentacene adlayers, it seemed to help the adsorption of pentacene molecules in a long-range ordered pattern. At room temperature (25 degrees C), approximately 100 pentacene molecules seen in STM images could rotate and align themselves to a neighboring domain in 10 s, suggesting that pentacene admolecules could be mobile on Au(111) under the STM imaging conditions of -150 mV in bias voltage and 1 nA in feedback current.

Adsorption of dissolved organics in lake water by aluminum oxide. Effect of molecular weight

USGS Publications Warehouse

Davis, J.A.; Gloor, R.

1981-01-01

Dissolved organic compounds in a Swiss lake were fractionated into three molecular size classes by gel exclusion chromatography, and adsorption of each fraction on colloidal alumina was studied as a function of pH. Organic compounds with molecular weight (Mr) greater than 1000 formed strong complexes with the alumina surface, but low molecular weight compounds were weakly adsorbed. Electrophoretic mobility measurements indicated that alumina particles suspended in the original lake water were highly negatively charged because of adsorbed organic matter. Most of the adsorbed organic compounds were in the Mr range 1000 < Mr < 3000. Adsorption of these compounds during the treatment of drinking water by alum coagulation may be responsible for the preferential removal of trihalomethane precursors. Adsorption may also influence the molecular-weight distribution of dissolved organic material in lakes. surface, the present work will focus on the influence of molecular size and pH on the adsorption behavior of dissolved organic material of a Swiss lake. From a geochemical point of view, it is important to know the molecular-weight distribution of adsorbed organic matter so that we may better assess its reactivity with trace elements. The study also serves as a first step in quantifying the role of adsorption in the geochemical cycle of organic carbon in lacustrine environments. For water-treatment practice, we need to determine whether molecular weight fractionation occurs during adsorption by aluminum oxide. Such a fractionation could be significant in the light of recent reports that chloroform and other organochlorine compounds are preferentially produced by particular molecular-weight fractions (25-27). ?? 1981 American Chemical Society.

Biochar Enhances Aspergillus niger Rock Phosphate Solubilization by Increasing Organic Acid Production and Alleviating Fluoride Toxicity

PubMed Central

Mendes, Gilberto de Oliveira; Zafra, David Lopez; Vassilev, Nikolay Bojkov; Silva, Ivo Ribeiro; Ribeiro, José Ivo

2014-01-01

During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F−) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F− adsorbents [activated alumina (Al2O3) and biochar] on RP solubilization by Aspergillus niger was examined. Al2O3 adsorbed part of the F− released but also adsorbed soluble P, which makes it inappropriate for microbial RP solubilization systems. In contrast, biochar adsorbed only F− while enhancing phosphate solubilization 3-fold, leading to the accumulation of up to 160 mg of P per liter. By comparing the values of F− measured in solution at the end of incubation and those from a predictive model, it was estimated that up to 19 mg of F− per liter can be removed from solution by biochar when added at 3 g liter−1 to the culture medium. Thus, biochar acted as an F− sink during RP solubilization and led to an F− concentration in solution that was less inhibitory to the process. In the presence of biochar, A. niger produced larger amounts of citric, gluconic, and oxalic acids, whether RP was present or not. Our results show that biochar enhances RP solubilization through two interrelated processes: partial removal of the released F− and increased organic acid production. Given the importance of organic acids for P solubilization and that most of the RPs contain high concentrations of F−, the proposed solubilization system offers an important technological improvement for the microbial production of soluble P fertilizers from RP. PMID:24610849

Nanostructured carbon materials for adsorption of methane and other gases

DOEpatents

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.

Investigations Into the Reusability of Amidoxime-Based Polymeric Uranium Adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, Li-Jung; Gill, Gary A.; Strivens, Jonathan E.

Significant advancements in amidoxime-based polymeric adsorbents to extract uranium from seawater are achieved in recent years. The success of uranium adsorbent development can help provide a sustainable supply of fuel for nuclear reactors. To bring down the production cost of this new technology, in addition to the development of novel adsorbents with high uranium capacity and manufacture cost, the development of adsorbent re-using technique is critical because it can further reduce the cost of the adsorbent manufacture. In our last report, the use of high concentrations of bicarbonate solution (3M KHCO3) was identified as a cost-effective, environmental friendly method tomore » strip uranium from amidoxime-based polymeric adsorbents. This study aims to further improve the method for high recovery of uranium capacity in re-uses and to evaluate the performance of adsorbents after multiple re-use cycles. Adsorption of dissolved organic matter (DOM) on the uranium adsorbents during seawater exposure can hinder the uranium adsorption and slow down the adsorption rate. An additional NaOH rinse (0.5 M NaOH, room temperature) was applied after the 3 M KHCO3 elution to remove natural organic matter from adsorbents. The combination of 3 M KHCO3 elution and 0.5 M NaOH rinse significantly improves the recovery of uranium adsorption capacity in the re-used adsorbents. In the first re-use, most ORNL adsorbents tested achieve ~100% recovery by using 3 M KHCO3 elution + 0.5 M NaOH rinse approach, in comparison to 54% recovery when only 3 M KHCO3 elution was applied. A significant drop in capacity was observed when the adsorbents went through more than one re-use. FTIR spectra revealed that degradation of amidoxime ligands occurs during seawater exposure, and is more significant the longer the exposure time. Significantly elevated ratios of Ca/U and Mg/U in re-used adsorbents support the decrease in abundance of amidoxime ligands and increase carboxylate group from FT-IR analysis. The impact of the length of seawater exposure cycle in adsorbent re-use was evaluated by comparing the adsorption capacity for a common adsorbent formulation (ORNL AI8 formulation) under different exposure cycle (28 days and 42 days). Adsorbents with a 28 days seawater exposure cycle had higher recovery of uranium capacity than adsorbent with 42 days of seawater exposure. Under different cumulative seawater exposure time, the adsorbent with 28 days seawater exposure cycle also had less amidoxime ligands degradation than the adsorbent with 42 days seawater exposure cycle. These observations support the negative impact of prolonged seawater exposure on amidoxime ligands stability. Recovery of uranium capacity in re-uses also varies across different adsorbent formulations. Among three different ORNL adsorbents tested (AI8, AF8, AF1-DMSO), AI8 had the best recovery in each re-use, followed by AF8 and then AF1-DMSO. This demonstrates that continuing efforts on developing new adsorbents with high capacity and stability is critical. The overall performance of adsorbents in multiple re-use cycles can be evaluated by calculation total harvestable uranium, the summation of adsorbed uranium from each seawater exposure cycle. In this assessment, the ORNL AI8 braid with 28 days seawater exposure cycle can reach total harvestable uranium 10g Uranium/kg adsorbent in ~140 days; while the same type of braid but with 42 days seawater exposure cycle reach the same level in ~170 days. Notably, the performance of total harvestable uranium also varies among different adsorbent formulations (AI8 > AF1-DMSO > AF8). Short seawater exposure cycle is associated with high re-use frequency. The development of low-cost offshore adsorbent deployment/extraction is essential for high frequency reuse operation. This study also highlights the importance to examine the re-use performance of newly developed uranium adsorbents for selection of optimal adsorbents for ocean deployment.« less

Surface-micromachined chain for use in microelectromechanical structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vernon, Sr., George E.

2001-01-01

A surface-micromachined chain and a microelectromechanical (MEM) structure incorporating such a chain are disclosed. The surface-micromachined chain can be fabricated in place on a substrate (e.g. a silicon substrate) by depositing and patterning a plurality of alternating layers of a chain-forming material (e.g. polycrystalline silicon) and a sacrificial material (e.g. silicon dioxide or a silicate glass). The sacrificial material is then removed by etching to release the chain for movement. The chain has applications for forming various types of MEM devices which include a microengine (e.g. an electrostatic motor) connected to rotate a drive sprocket, with the surface-micromachined chain beingmore » connected between the drive sprocket and one or more driven sprockets.« less

Microfluidic hydrogels for tissue engineering.

PubMed

Huang, Guo You; Zhou, Li Hong; Zhang, Qian Cheng; Chen, Yong Mei; Sun, Wei; Xu, Feng; Lu, Tian Jian

2011-03-01

With advanced properties similar to the native extracellular matrix, hydrogels have found widespread applications in tissue engineering. Hydrogel-based cellular constructs have been successfully developed to engineer different tissues such as skin, cartilage and bladder. Whilst significant advances have been made, it is still challenging to fabricate large and complex functional tissues due mainly to the limited diffusion capability of hydrogels. The integration of microfluidic networks and hydrogels can greatly enhance mass transport in hydrogels and spatiotemporally control the chemical microenvironment of cells, mimicking the function of native microvessels. In this review, we present and discuss recent advances in the fabrication of microfluidic hydrogels from the viewpoint of tissue engineering. Further development of new hydrogels and microengineering technologies will have a great impact on tissue engineering.

Microfabrication of individual 200 microm diameter transdermal microconduits using high voltage pulsing in salicylic acid and benzoic acid.

PubMed

Ilic, L; Gowrishankar, T R; Vaughan, T E; Herndon, T O; Weaver, J C

2001-01-01

We describe an extension of semiconductor fabrication methods that creates individual approximately 200 microm diameter aqueous pathways through human stratum corneum at predetermined sites. Our hypothesis is that spatially localized electroporation of the multilamellar lipid bilayer membranes provides rapid delivery of salicylic acid to the keratin within corneocytes, leading to localized keratin disruption and then to a microconduit. A microconduit penetrating the isolated stratum corneum supports a volumetric flow of order 0.01 ml per s with a pressure difference of only 0.01 atm (about 10(2) Pa). This study provides a method for rapidly microengineering a pathway in the skin to interface future devices for transdermal drug delivery and sampling of biologically relevant fluids.

Review: nanoparticles in delivery of cardiovascular drugs.

PubMed

Arayne, M Saeed; Sultana, Najma; Qureshi, Faiza

2007-10-01

Everything in nature is built upward from the atomic level to define limits and structures to everything. Nanomedicines marked the field of medicine from nanobiotechnology, biological micro-electromechanical systems, microfluidics, biosensors, drug delivery, microarrays to tissue microengineering. Since then nanoparticles has overcome many challenges from blood brain barrier to targeting tumors. Where solid biodegradable nanoparticles were a step up liposome, targeting nanoparticles opened a whole new field for drug delivery. In this article, we attempt to discuss how the pioneered technique is serving in the drug delivery to cardiovascular system and how with the manipulation of their properties, nanoparticles can be made to fulfill desired function. Also how nanocarriers are improving molecular imaging to help improve diagnosis and treatment of cardiovascular disease is focused in this article.

Organs-on-chips at the frontiers of drug discovery

PubMed Central

Esch, Eric W.; Bahinski, Anthony; Huh, Dongeun

2016-01-01

Improving the effectiveness of preclinical predictions of human drug responses is critical to reducing costly failures in clinical trials. Recent advances in cell biology, microfabrication and microfluidics have enabled the development of microengineered models of the functional units of human organs — known as organs-on-chips — that could provide the basis for preclinical assays with greater predictive power. Here, we examine the new opportunities for the application of organ-on-chip technologies in a range of areas in preclinical drug discovery, such as target identification and validation, target-based screening, and phenotypic screening. We also discuss emerging drug discovery opportunities enabled by organs-on-chips, as well as important challenges in realizing the full potential of this technology. PMID:25792263

Gas-Solid Dynamics at Disordered and Adsorbate Covered Surfaces

DTIC Science & Technology

1992-09-02

interesting physical problems in which non-linear reactions occur at localized defects. The Lotka - Volterra system is considered, in which the source, sink...designing external optical fields for manipulating molecular scale events. A general formulation of the theory was developed, for treating rotational...interrelated avenues of study were pursued. The goals of the research were achieved, thereby producing a general theoretical framework for both optimal

Peat

USGS Publications Warehouse

Apodaca, Lori E.

2013-01-01

The article looks at the U.S. peat market as of July 2013. Peat is produced from deposits of plant organic materials in wetlands and includes varieties such as reed-sedge, sphagnum moss, and humus. Use for peat include horticultural soil additives, filtration, and adsorbents. Other topics include effects of environmental protection regulations on peat extraction, competition from products such as coir, composted organic waste, and wood products, and peatland carbon sinks.

MIPs as Tools in Environmental Biotechnology.

PubMed

Mattiasson, Bo

2015-01-01

Molecular imprints are potentially fantastic constructions. They are selective, robust, and nonbiodegradable if produced from stable polymers. A range of different applications has been presented, everything from separation of enantiomers, via adsorbents for sample preparation before analysis to applications in wastewater treatment. This chapter deals with molecularly imprinted polymers (MIPs) as tools in environmental biotechnology, a field that has the potential to become very important in the future.

Deformability of adsorbents during adsorption and principles of the thermodynamics of solid-phase systems

NASA Astrophysics Data System (ADS)

Tovbin, Yu. K.

2017-09-01

A microscopic theory of adsorption, based on a discrete continuum lattice gas model for noninert (including deformable) adsorbents that change their lattice parameters during adsorption, is presented. Cases of the complete and partial equilibrium states of the adsorbent are considered. In the former, the adsorbent consists of coexisting solid and vapor phases of adsorbent components, and the adsorbate is a mobile component of the vapor phase with an arbitrary density (up to that of the liquid adsorbate phase). The adsorptive transitioning to the bound state changes the state of the near-surface region of the adsorbent. In the latter, there are no equilibrium components of the adsorbent between the solid and vapor phases. The adsorbent state is shown to be determined by its prehistory, rather than set by chemical potentials of vapor of its components. Relations between the microscopic theory and thermodynamic interpretations are discussed: (1) adsorption on an open surface, (2) two-dimensional stratification of the adsorbate mobile phase on an open homogeneous surface, (3) small microcrystals in vacuum and the gas phase, and (4) adsorption in porous systems.

Plasmid-controlled colonization factor associated with virulence in Esherichia coli enterotoxigenic for humans.

PubMed Central

Evans, D G; Silver, R P; Evans, D J; Chase, D G; Gorbach, S L

1975-01-01

An enterotoxin-producing strain of Escherichia coli isolated from a case of cholera-like diarrhea (E. coli strain H-10407) was found to possess a surface-associated colonization factor. Colonization was manifested as the ability of small inocula (10(5) bacteria) to attain large (10(9)) populations in the infant rabbit intestine with a concomitant diarrheal response. A laboratory-passed derivative of E. coli H-10407, designated H-10407-P, failed to exhibit an increase in population in the infant rabbit and also failed to induce diarrhea. Cell-free culture supernatant fluids of E. coli H-10407 and H-10407-P produced equivalent enterotoxic responses in infant and in adult rabbits. Specific anti-colonization factor antiserum was produced by adsorbing hyperimmune anti-H-10407 serum with both heat-killed and living cells E. coli H-10407-P. This specific adsorbed serum protected infant rabbits from challenge with living E. coli H-10407 although the serum did not possess bactericidal activity. The anti-colonization factor serum did not agglutinate a strain of E. coli K-12 possessing the K88 colonization factor peculiar to E. coli enterotoxigenic for swine. By electron microscopy it was demonstrated that E. coli H-10407, but not H10407-, possessed pilus-like surface structures which agglutinated with the specific adsorbed (anti-colonization factor) antiserum. E. coli H-10407 possessed three species of plasmid deoxyribonucleic acid, measuring 60 X 10(6), 42 X 10(6), and 3.7 X 10(6) daltons, respectively. E. coli H-10407-P possessed only the 42 X 10(6)- and the 3.7 X 10(6)-dalton plasmid species. Spontaneous loss of the specific H-10407 surface-associated antigen was accompanied by loss of the 60 X 10(6)-dalton species of plasmid deoxyribonucleic acid and loss of colonizing ability. Thus, it is concluded that the E. coli colonization factor described here is a virulence factor which may play an important and possibly essential role in naturally occurring E. coli enterotoxic diarrhea in man. Images PMID:1100526

Plasmid-controlled colonization factor associated with virulence in Esherichia coli enterotoxigenic for humans.

PubMed

Evans, D G; Silver, R P; Evans, D J; Chase, D G; Gorbach, S L

1975-09-01

An enterotoxin-producing strain of Escherichia coli isolated from a case of cholera-like diarrhea (E. coli strain H-10407) was found to possess a surface-associated colonization factor. Colonization was manifested as the ability of small inocula (10(5) bacteria) to attain large (10(9)) populations in the infant rabbit intestine with a concomitant diarrheal response. A laboratory-passed derivative of E. coli H-10407, designated H-10407-P, failed to exhibit an increase in population in the infant rabbit and also failed to induce diarrhea. Cell-free culture supernatant fluids of E. coli H-10407 and H-10407-P produced equivalent enterotoxic responses in infant and in adult rabbits. Specific anti-colonization factor antiserum was produced by adsorbing hyperimmune anti-H-10407 serum with both heat-killed and living cells E. coli H-10407-P. This specific adsorbed serum protected infant rabbits from challenge with living E. coli H-10407 although the serum did not possess bactericidal activity. The anti-colonization factor serum did not agglutinate a strain of E. coli K-12 possessing the K88 colonization factor peculiar to E. coli enterotoxigenic for swine. By electron microscopy it was demonstrated that E. coli H-10407, but not H10407-, possessed pilus-like surface structures which agglutinated with the specific adsorbed (anti-colonization factor) antiserum. E. coli H-10407 possessed three species of plasmid deoxyribonucleic acid, measuring 60 X 10(6), 42 X 10(6), and 3.7 X 10(6) daltons, respectively. E. coli H-10407-P possessed only the 42 X 10(6)- and the 3.7 X 10(6)-dalton plasmid species. Spontaneous loss of the specific H-10407 surface-associated antigen was accompanied by loss of the 60 X 10(6)-dalton species of plasmid deoxyribonucleic acid and loss of colonizing ability. Thus, it is concluded that the E. coli colonization factor described here is a virulence factor which may play an important and possibly essential role in naturally occurring E. coli enterotoxic diarrhea in man.

The Uranium from Seawater Program at the Pacific Northwest National Laboratory: Overview of Marine Testing, Adsorbent Characterization, Adsorbent Durability, Adsorbent Toxicity, and Deployment Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Gary A.; Kuo, Li-Jung; Janke, Chris J.

The Pacific Northwest National Laboratory’s (PNNL) Marine Science Laboratory (MSL) located along the coast of Washington State is evaluating the performance of uranium adsorption materials being developed for seawater extraction under realistic marine conditions with natural seawater. Two types of exposure systems were employed in this program: flow-through columns for testing of fixed beds of individual fibers and pellets and a recirculating water flume for testing of braided adsorbent material. Testing consists of measurements of the adsorption of uranium and other elements from seawater as a function of time, typically 42 to 56 day exposures, to determine the adsorbent capacitymore » and adsorption rate (kinetics). Analysis of uranium and other trace elements collected by the adsorbents was conducted following strong acid digestion of the adsorbent with 50% aqua regia using either Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The ORNL 38H adsorbent had a 56 day adsorption capacity of 3.30 ± 0.68 g U/ kg adsorbent (normalized to a salinity of 35 psu), a saturation adsorption capacity of 4.89 ± 0.83 g U/kg of adsorbent material (normalized to a salinity of 35 psu) and a half-saturation time of 28 ± 10 days. The AF1 adsorbent material had a 56 day adsorption capacity of 3.9 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu), a saturation capacity of 5.4 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu) and a half saturation time of 23 ± 2 days. The ORNL amidoxime-based adsorbent materials are not specific for uranium, but also adsorb other elements from seawater. The major doubly charged cations in seawater (Ca and Mg) account for a majority of the cations adsorbed (61% by mass and 74% by molar percent). For the ORNL AF1 adsorbent material, U is the 4th most abundant element adsorbed by mass and 7th most abundant by molar percentage« less

Effect of Micellization on the Adsorption Kinetics of Polymeric Surfactants to the Solid/Water Interface

NASA Astrophysics Data System (ADS)

Toomey, Ryan; Tirrell, Matthew

2002-03-01

We have studied the adsorption kinetics of two classes of hydrophobic/ionic diblock copolymer surfactants in aqueous environments to understand the role that micellization plays in the adsorption process. The two systems studied were poly(t-butyl styrene)-block-poly(styrene sulfonate) (PtBS-b-PSS) and polystyrene-block-poly(acrylic acid) (PS-b-PAA). It is found that by changing the hydrophobicity of the adsorbing surface, micelle adsorption can be turned on or off. When micelle adsorption occurs, the initial adsorption rate is always slower than the supply rate of micelles to the surface, indicating “reaction-limited” adsorption. Since these micelles have essentially frozen cores, the adsorption cannot be explained by the release of unimers from the micelles. Rather, micelles directly adsorb, and they have to overcome the potential barrier imposed by their corona. Due to micellization, the adsorption rate can also be a complex function of ionic strength. A regime was found where the initial adsorption rate decreased with increasing ionic strength. This anomaly can be explained by the onset of micellization. As the salt concentration is increased, more micelles are formed. However micelles adsorb roughly an order of magnitude slower than free chains. Therefore, if increasing the ionic strength produces more micelles, the adsorption rate will simultaneously decrease.

Application of low energy ion blocking for adsorption site determination of Na Atoms on a Cu(111) surface

NASA Astrophysics Data System (ADS)

Zhang, R.; Makarenko, B.; Bahrim, B.; Rabalais, J. W.

2010-07-01

Ion blocking in the low keV energy range is demonstrated to be a sensitive method for probing surface adsorption sites by means of the technique of time-of-flight scattering and recoiling spectroscopy (TOF-SARS). Adsorbed atoms can block the nearly isotropic backscattering of primary ions from surface atoms in the outmost layers of a crystal. The relative adsorption site position can be derived unambiguously by simple geometrical constructs between the adsorbed atom site and the surface atom sites. Classical ion trajectory simulations using the scattering and recoiling imaging code (SARIC) and molecular dynamics (MD) simulations provide the detailed ion trajectories. Herein we present a quantitative analysis of the blocking effects produced by sub-monolayer Na adsorbed on a Cu(111) surface at room temperature. The results show that the Na adsorption site preferences are different at different Na coverages. At a coverage θ = 0.25 monolayer, Na atoms preferentially populate the fcc threefold surface sites with a height of 2.7 ± 0.1 Å above the 1st layer Cu atoms. At a lower coverage of θ = 0.10 monolayer, there is no adsorption site preference for the Na atoms on the Cu(111) surface.

Treatability of stabilize landfill leachate by using pressmud ash as an adsorbent

NASA Astrophysics Data System (ADS)

Azme, N. N. Mohd; Murshed, M. F.

2018-04-01

Leachate is a liquid produced from the landfill that contains high concentration of heavy metals, chemicals and nutrient loading. The treatability of these contaminants are complicated since the current treatment technology are costly and site specific. Therefore, this study was conducted to evaluate the treatability of stabilized landfill leachate by using waste (pressmud ash) as an absorbent. Pressmud ash was prepared by burning at different temperature from 100 to 700 degree Celsius and test at 24 hours shaking time, pH 8, and 4000 rpm. Leachate samples were collected from municipal solid waste (MSW) Pulau Burung Sanitary Landfill (PBSL) and were analyzed for heavy metal, COD, ammonia and colour. This study was performed in two phases i) leachate characteristic, ii) treatability assessment by using pressmud ash. Pressmud was sampled from the sugar mill, Malaysian Sugar Manufacturing (MSM) Sdn Bhd, Seberang Perai, Pulau Pinang. The pressmud with 400°C are highly potential material with a low cost which can be a good adsorbent was capable reducing efficiencies of COD (60.76%), ammonia (64.37%) and colour (35.78%) from real wastewater leachate. Pressmud showed good sorption capability. Surface modification with burning greatly enhanced the reducing efficiency of sugar waste based adsorbent with adsorption efficiency.

Efficient boron abstraction using honeycomb-like porous magnetic hybrids: Assessment of techno-economic recovery of boric acid.

PubMed

Oladipo, Akeem Adeyemi; Gazi, Mustafa

2016-12-01

Porous magnetic hybrids were synthesized and functionalized with glycidol to produce boron-selective adsorbent. The magnetic hybrid (MH) comparatively out-performed the existing expensive adsorbents. MH had a saturation magnetisation of 63.48 emu/g and average pore diameter ranging from meso to macropores. The magnetic hybrids showed excellent selectivity towards boron and resulted in 79-93% boron removal even in the presence of competing metal ions (Na + and Cr 2+ ). Experiments were performed in a column system, and breakthrough time was observed to increase with bed depths and decreased with flow rates. The batch experiments revealed that 60 min was enough to achieve equilibrium, and the level of boron sorption was 108.5 mg/g from a synthetic solution. Several adsorption-desorption cycles were performed using a simple acid-water treatment and evaluated using various kinetic models. The spent adsorbents could be separated easily from the mixture by an external magnetic field. The cost-benefit analysis was performed for the treatment of 72 m 3 /year boron effluent, including five years straight line depreciation charges of equipment. The net profit and standard percentage confirmed that the recovery process is economically feasible. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biogas pre-upgrading by adsorption of trace compounds onto granular activated carbons and an activated carbon fiber-cloth.

PubMed

Boulinguiez, B; Le Cloirec, P

2009-01-01

The study assesses the adsorption onto activated carbon materials of selected volatile organic compounds -VOCs- (dichloromethane, 2-propanol, toluene, siloxane D4) in a biogas matrix composed of methane and carbon dioxide (55:45 v/v). Three different adsorbents are tested, two of them are granular activated carbon (GAC), and the last is an activated carbon fiber-cloth (ACFC). The adsorption isotherm data are fitted by different models by nonlinear regression. The Langmuir-Freundlich model appears to be the adequate one to describe the adsorption phenomena independently of the VOC considered or the adsorbent. The adsorbents present attractive adsorption capacity of the undesirable compounds in biogas atmosphere though the maximum adsorption capacities for a VOC are quite different from each other. The adsorption kinetics are characterized through three coefficients: the initial adsorption coefficient, the external film mass transfer coefficient and the internal diffusion coefficient of Weber. The ACFC demonstrates advanced kinetic yields compared to the granular activated carbon materials whatever VOC is considered. Therefore, pre-upgrading of biogas produced from wastewater sludge or co-digestion system by adsorption onto activated carbon appears worth investigating. Especially with ACFC material that presents correct adsorption capacities toward VOCs and concrete regeneration process opportunity to realize such process.

Revealing cytokine-induced changes in the extracellular matrix with secondary ion mass spectrometry

PubMed Central

Taylor, Adam J; Ratner, Buddy D; Buttery, Lee DK; Alexander, Morgan R

2015-01-01

Cell-secreted matrices (CSMs), where extracellular matrix (ECM) deposited by monolayer cell cultures are decellularized, have been increasingly used to produce surfaces that may be reseeded with cells. Such surfaces are useful to help us understand cell-ECM interactions in a microenvironment closer to the in vivo situation than synthetic substrates with adsorbed proteins. We describe the production of CSMs from mouse primary osteoblasts (mPObs) exposed to cytokine challenge during matrix secretion, mimicking in vivo inflammatory environments. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) data revealed that CSMs with cytokine challenge at day 7 or day 12 of culture can be chemically distinguished from one another and from untreated CSM using multivariate analysis. Comparison of the differences with reference spectra from adsorbed protein mixtures points towards cytokine challenge resulting in a decrease in collagen content. This is supported by immunocytochemical and histological staining, demonstrating a 44% loss of collagen mass and a 32% loss in collagen I coverage. CSM surfaces demonstrate greater cell adhesion than adsorbed ECM proteins. When mPObs were reseeded onto cytokine-challenged CSMs they exhibited reduced adhesion and elongated morphology compared to untreated CSMs. Such changes may direct subsequent cell fate and function and provide insights into pathological responses at sites of inflammation. PMID:25523877

Formation and Stabilization of Combustion-Generated, Environmentally Persistent Radicals on Ni(II)O Supported on a Silica Surface

PubMed Central

Vejerano, Eric; Lomnicki, Slawomir M.; Dellinger, Barry

2013-01-01

Previous studies have indicated Environmentally Persistent Free Radicals (EPFRs) are formed when hydroxyl- and chlorine-substituted aromatics chemisorbed on Cu(II)O and Fe(III)2O3 surfaces and were stabilized through their interactions with the surface metal cation. The current study reports our laboratory investigation on the formation and stabilization of EPFRs on an Ni(II)O surface. The EPFRs were produced by the chemisorption of adsorbates on the supported metal oxide surface and transfer of an electron from the adsorbate to the metal center, resulting in reduction of the metal cation. Depending on the temperature and the nature of the adsorbate, more than one type of organic radical was formed. A phenoxyl-type radical, with g-value between 2.0029 and 2.0044, and a semiquinone-type radical, with g-value from 2.0050 to as high as 2.0081, were observed. The half-lives on Ni(II)O were long and ranged from 1.5 to 5.2 days, which were similar to what were observed on Fe(III)2O3,. The yields of the EPFRs formed on Ni(II)O was ~ 8x higher than on Cu(II)O and ~50x higher than on Fe(III)2O3. PMID:22831558

Kinetic Assembly of Near-IR Active Gold Nanoclusters using Weakly Adsorbing Polymers to Control Size

PubMed Central

Tam, Jasmine M.; Murthy, Avinash K.; Ingram, Davis R.; Nguyen, Robin; Sokolov, Konstantin V.; Johnston, Keith P.

2013-01-01

Clusters of metal nanoparticles with an overall size less than 100 nm and high metal loadings for strong optical functionality, are of interest in various fields including microelectronics, sensors, optoelectronics and biomedical imaging and therapeutics. Herein we assemble ~5 nm gold particles into clusters with controlled size, as small as 30 nm and up to 100 nm, which contain only small amounts of polymeric stabilizers. The assembly is kinetically controlled with weakly adsorbing polymers, PLA(2K)-b-PEG(10K)-b-PLA(2K) or PEG (MW = 3350), by manipulating electrostatic, van der Waals (VDW), steric, and depletion forces. The cluster size and optical properties are tuned as a function of particle volume fractions and polymer/gold ratios to modulate the interparticle interactions. The close spacing between the constituent gold nanoparticles and high gold loadings (80–85% w/w gold) produce a strong absorbance cross section of ~9×10−15 m2 in the NIR at 700 nm. This morphology results from VDW and depletion attractive interactions that exclude the weakly adsorbed polymeric stabilizer from the cluster interior. The generality of this kinetic assembly platform is demonstrated for gold nanoparticles with a range of surface charges from highly negative to neutral, with the two different polymers. PMID:20361735

Interaction of gases with lunar materials. [surface properties of lunar fines, especially on exposure to water vapor

NASA Technical Reports Server (NTRS)

Holmes, H. F.; Gammage, R. B.

1975-01-01

The surface properties of lunar fines were investigated. Results indicate that, for the most part, these properties are independent of the chemical composition and location of the samples on the lunar surface. The leaching of channels and pores by adsorbed water vapor is a distinguishing feature of their surface chemistry. The elements of air, if adsorbed in conjunction with water vapor or liquid water, severely impedes the leaching process. In the absence of air, liquid water is more effective than water vapor in attacking the grains. The characteristics of Apollo 17 orange fines were evaluated and compared with those of other samples. The interconnecting channels produced by water vapor adsorption were found to be wider than usual for other types of fines. Damage tracks caused by heavy cosmic ray nuclei and an unusually high halogen content might provide for stronger etching conditions upon exposure to water vapor.

Phenol adsorption by activated carbon produced from spent coffee grounds.

PubMed

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.

Surface enhanced Raman scattering of amino acids assisted by gold nanoparticles and Gd(3+) ions.

PubMed

López-Neira, Juan Pablo; Galicia-Hernández, José Mario; Reyes-Coronado, Alejandro; Pérez, Elías; Castillo-Rivera, Francisco

2015-05-07

The surface enhanced raman scattering (SERS) signal from the l-tyrosine (tyr) molecule adsorbed on gold nanoparticles (Au-tyr) is compared with the SERS signal assisted by the presence of gadolinium ions (Gd(3+)) coordinated with the Au-tyr system. An enhancement factor of the SERS signal in the presence of Gd(3+) ions was ∼5 times higher than that produced by l-tyrosine adsorbed on gold nanoparticles. The enhancement of the SERS signal can be attributed to a corresponding increase in the local electric field due to the presence of Gd(3+) ions in the vicinity of a gold dimer configuration. This scenario was confirmed by solving numerically Maxwell equations, showing an increase of 1 order of magnitude in the local electric scattered field when the Gd(3+) ion is located in between a gold dimer compared with naked gold nanoparticles.

Surface characterization of adsorbents in ultrasound-assisted oxidative desulfurization process of fossil fuels.

PubMed

Etemadi, Omid; Yen, Teh Fu

2007-09-01

Surface properties of two different phases of alumina were studied through SEM images. Characterization of amorphous acidic alumina and crystalline boehmite by XRD explains the differences in adsorption capacities of each sample. Data from small angle neutron scattering (SANS) provide further results regarding the ordering in amorphous and crystalline samples of alumina. Quantitative measurements from SANS are used for pore size calculations. Higher disorder provides more topological traps, irregularities, and hidden grooves for higher adsorption capacity. An isotherm model was derived for adsorption of dibenzothiophene sulfone (DBTO) by amorphous acidic alumina to predict and calculate the adsorption of sulfur compounds. The Langmuir-Freundlich model covers a wide range of sulfur concentrations. Experiments prove that amorphous acidic alumina is the adsorbent of choice for selective adsorption in the ultrasound-assisted oxidative desulfurization (UAOD) process to produce ultra-low-sulfur fuel (ULSF).

Metal-organic frameworks for upgrading biogas via CO2 adsorption to biogas green energy.

PubMed

Chaemchuen, Somboon; Kabir, Nawsad Alam; Zhou, Kui; Verpoort, Francis

2013-12-21

In the midst of the global climate change phenomenon, mainly caused by fossil fuel burning to provide energy for our daily life and discharge of CO2 into the atmosphere, biogas is one of the important renewable energy sources that can be upgraded and applied as a fuel source for energy in daily life. The advantages of the production of hybrid materials, metal-organic framework (MOF) adsorbents, expected for the biogas upgrading, rely on the bulk separation of CO2 under near-ambient conditions. This review highlights the challenges for MOF adsorbents, which have the greatest upgrading abilities for biogas via selective passage of methane. The key factors improving the ideal MOF materials for these high CO2 capture and selectivity uses for biogas upgrading to produce bio-methane and reduce fossil-fuel CO2 emission will be discussed.

Functionalized Ga2O3 nanowires as active material in room temperature capacitance-based gas sensors.

PubMed

Mazeina, Lena; Perkins, F Keith; Bermudez, Victor M; Arnold, Stephen P; Prokes, S M

2010-08-17

We report the first evidence for functionalization of Ga(2)O(3) nanowires (NWs), which have been incorporated as the active material in room temperature capacitance gas-sensing devices. An adsorbed layer of pyruvic acid (PA) was successfully formed on Ga(2)O(3) NWs by simple room temperature vapor transport, which was confirmed by Fourier transform infrared spectroscopy. The effect of the adsorbed PA on the surface properties was demonstrated by the change in the response of the NW gas-sensing devices. Results indicate that the adsorption of PA reduced the sensitivity of the Ga(2)O(3) NW device to common hydrocarbons such as nitromethane and acetone while improving the response to triethylamine by an order of magnitude. Taking into account the simplicity of this functionalization together with the ease of producing these capacitance-based gas-sensing devices, this approach represents a viable technique for sensor development.

Influence of Polyvinyl Alcohol (PVA) Addition on Silica Membrane Performance Prepared from Rice Straw

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Ramelan, A. H.; Wardoyo, D. T.; Ichsan, S.; Kristiawan, Y. R.

2018-03-01

The utilization and modification of silica from rice straw as the main ingredient of adsorbent has been studied. The aim of this study was to determine the optimum composition of PVA (polyvinyl alcohol): silica to produce adsorbents with excellent pore characteristics, optimum adsorption efficiency and optimum pH for methyl yellow adsorptions. X-Ray Fluorescence (XRF) analysis results showed that straw ash contains 82.12 % of silica (SiO2). SAA (Surface Area Analyzer) analysis showed optimum composition ratio 5:5 of PVA: silica with surface area of 1.503 m2/g. Besides, based on the pore size distribution of PVA: silica (5:5) showed the narrow pore size distribution with the largest pore cumulative volume of 2.8 x 10-3 cc/g. The optimum pH for Methanyl Yellow adsorption is pH 2 with adsorption capacity = 72.1346%.

Spectroscopic Studies of Abiotic and Biological Nanomaterials: Silver Nanoparticles, Rhodamine 6G Adsorbed on Graphene, and c-Type Cytochromes and Type IV Pili in Geobacter sulfurreducens

NASA Astrophysics Data System (ADS)

Thrall, Elizabeth S.

This thesis describes spectroscopic studies of three different systems: silver nanoparticles, the dye molecule rhodamine 6G adsorbed on graphene, and the type IV pili and c-type cytochromes produced by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens. Although these systems are quite different in some ways, they can all be considered examples of nanomaterials. A nanomaterial is generally defined as having at least one dimension below 100 nm in size. Silver nanoparticles, with sub-100 nm size in all dimensions, are examples of zero-dimensional nanomaterials. Graphene, a single atomic layer of carbon atoms, is the paradigmatic two-dimensional nanomaterial. And although bacterial cells are on the order of 1 μm in size, the type IV pili and multiheme c-type cytochromes produced by G. sulfurreducens can be considered to be one- and zero-dimensional nanomaterials respectively. A further connection between these systems is their strong interaction with visible light, allowing us to study them using similar spectroscopic tools. The first chapter of this thesis describes research on the plasmon-mediated photochemistry of silver nanoparticles. Silver nanoparticles support coherent electron oscillations, known as localized surface plasmons, at resonance frequencies that depend on the particle size and shape and the local dielectric environment. Nanoparticle absorption and scattering cross-sections are maximized at surface plasmon resonance frequencies, and the electromagnetic field is amplified near the particle surface. Plasmonic effects can enhance the photochemistry of silver particles alone or in conjunction with semiconductors according to several mechanisms. We study the photooxidation of citrate by silver nanoparticles in a photoelectrochemical cell, focusing on the wavelength-dependence of the reaction rate and the role of the semiconductor substrate. We find that the citrate photooxidation rate does not track the plasmon resonance of the silver nanoparticles but instead rises monotonically with photon energy. These results are discussed in terms of plasmonic enhancement mechanisms and a theoretical model describing hot carrier photochemistry. The second chapter explores the electronic absorption and resonance Raman scattering of the dye molecule rhodamine 6G (R6G) adsorbed on graphene. Graphene has been shown to quench the fluorescence of adsorbed molecules and quantum dots, and some previous studies have reported that the Raman scattering from molecules adsorbed on graphene is enhanced. We show that reflective contrast spectroscopy can be used to obtain the electronic absorption spectrum of R6G adsorbed on graphene, allowing us to estimate the surface concentration of the dye molecule. From these results we are able to calculate the absolute Raman scattering cross-section for R6G adsorbed on bilayer graphene. We find that there is no evidence of enhancement but instead that the cross-section is reduced by more than three-fold from its value in solution. We further show that a model incorporating electromagnetic interference effects can reproduce the observed dependence of the R6G Raman intensity on the number of graphene layers. The third and final chapter describes the preliminary results from studies of the dissimilatory metal-reducing bacterium Geobacter sulfurreducens . This anaerobic bacterium couples the oxidation of organic carbon sources to the reduction of iron oxides and other extracellular electron acceptors, a type of anaerobic respiration that necessitates an electron transport chain that can move electrons from the interior of the cell to the extracellular environment. The electron transport chain in G. sulfurreducens has not been completely characterized and two competing mechanisms for the charge transport have been proposed. The first holds that G. sulfurreducens produces type IV pili, protein filaments several nanometers in width, with intrinsic metallic-like conductivity. According to this mechanism, the conductive pili mediate electron transport to extracellular acceptors. The second proposed mechanism is that charge transport proceeds by electron hopping between the heme groups in the many c-type cytochromes produced by G. sulfurreducens. In this picture, the observed conductivity of the pili is due to hopping through associated cytochrome proteins. Our aim is to explore these alternative mechanisms for electron transport in G. sulfurreducens through electrical and optical studies. We report the work we have done thus far to culture and characterize G. sulfurreducens , and we show that preliminary micro-Raman studies of G. sulfurreducens cells confirm that we can detect the spectroscopic signature of c-type cytochrome proteins. Future directions for this ongoing work are briefly discussed.

The influence of adsorbent microstructure upon adsorption equilibria: Investigations of a model system

NASA Astrophysics Data System (ADS)

Kaminsky, R. D.; Monson, P. A.

1991-08-01

We present a theoretical study of the influence of the microstructure of a porous adsorbent upon associated adsorption behavior. A model is developed which describes the interactions of adsorbed molecules with an adsorbent treated as a matrix of particles each of which is a continuum of interaction centers. The model leads to an analytic expression for the adsorbate-adsorbent particle potential which is an analog of the 9-3 potential model for adsorption on planar solid surfaces. To illustrate the utility of the approach, an application to methane adsorbed in a microporous silica gel is presented. Several adsorbent microstructures are investigated, including a variety of crystal lattices as well as structures derived from equilibrium configurations of hard spheres. Adsorption in these structures is studied through calculation of Henry's law constants and by using grand canonical Monte Carlo simulation to determine adsorption isotherms and the structure of adsorbed fluids. The results obtained are related to details of the adsorbent microstructure.

Kinetic modeling and transient DRIFTS–MS studies of CO 2 methanation over Ru/Al 2O 3 catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiang; Hong, Yongchun; Shi, Hui

CO 2 methanation was investigated on 5% and 0.5% Ru/Al 2O 3 catalysts (Ru dispersions: ~18% and ~40%, respectively) by steady-state kinetic measurements and transient DRIFTS–MS. Methanation rates were higher over 5% Ru/Al 2O 3 than over 0.5% Ru/Al 2O 3. The measured activation energies, however, were lower on 0.5% Ru/Al 2O 3 than on 5% Ru/Al 2O 3. Transient DRIFTS–MS results demonstrated that direct CO 2 dissociation was negligible over Ru. CO 2 has to first react with surface hydroxyls on Al 2O 3 to form bicarbonates, which, in turn, react with adsorbed H on Ru to produce adsorbed formate species. Formates, most likely at the metal/oxide interface, can react rapidly with adsorbed H forming adsorbed CO, only a portion of which is reactive toward adsorbed H, ultimately leading to CH4 formation. The measured kinetics are fully consistent with a Langmuir–Hinshelwood type mechanism in which the H-assisted dissociation of the reactive CO* is the rate-determining step (RDS). The similar empirical rate expressions (r CH4 = kPmore » $$0.1\\atop{CO2}$$P$$0.3-0.5\\atop{H2}$$) and DRIFTS–MS results on the two catalysts under both transient and steady-state conditions suggest that the mechanism for CO 2 methanation does not change with Ru particle size under the studied experimental conditions. Kinetic modeling results further indicate that the intrinsic activation barrier for the RDS is slightly lower on 0.5% Ru/Al 2O 3 than on 5% Ru/Al 2O 3. Due to the presence of unreactive adsorbed CO under reaction conditions, the larger fraction of such surface sites that bind CO too strongly on 0.5% Ru/Al 2O 3 than on 5% Ru/Al 2O 3, as revealed by FTIR measurements, is regarded as the main reason for the lower rates for CO 2 methanation on 0.5% Ru/Al 2O 3. The catalyst preparation and catalytic measurements were supported by a Laboratory Directed Research and Development (LDRD) project. The authors gratefully acknowledge the financial support of this work by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.« less

Production of activated carbons from waste tyres for low temperature NOx control.

PubMed

Al-Rahbi, Amal S; Williams, Paul T

2016-03-01

Waste tyres were pyrolysed in a bench scale reactor and the product chars were chemically activated with alkali chemical agents, KOH, K2CO3, NaOH and Na2CO3 to produce waste tyre derived activated carbons. The activated carbon products were then examined in terms of their ability to adsorb NOx (NO) at low temperature (25°C) from a simulated industrial process flue gas. This study investigates the influence of surface area and porosity of the carbons produced with the different alkali chemical activating agents on NO capture from the simulated flue gas. The influence of varying the chemical activation conditions on the porous texture and corresponding NO removal from the flue gas was studied. The activated carbon sorbents were characterized in relation to BET surface area, micropore and mesopore volumes and chemical composition. The highest NO removal efficiency for the waste tyre derived activated carbons was ∼75% which was obtained with the adsorbent treated with KOH which correlated with both the highest BET surface area and largest micropore volume. In contrast, the waste tyre derived activated carbons prepared using K2CO3, NaOH and Na2CO3 alkali activating agents appeared to have little influence on NO removal from the flue gases. The results suggest problematic waste tyres, have the potential to be converted to activated carbons with NOx removal efficiency comparable with conventionally produced carbons. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2014-05-01

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

Pyrolysis production of fruit peel biochar for potential use in treatment of palm oil mill effluent.

PubMed

Lam, Su Shiung; Liew, Rock Keey; Cheng, Chin Kui; Rasit, Nazaitulshila; Ooi, Chee Kuan; Ma, Nyuk Ling; Ng, Jo-Han; Lam, Wei Haur; Chong, Cheng Tung; Chase, Howard A

2018-05-01

Fruit peel, an abundant waste, represents a potential bio-resource to be converted into useful materials instead of being dumped in landfill sites. Palm oil mill effluent (POME) is a harmful waste that should also be treated before it can safely be released to the environment. In this study, pyrolysis of banana and orange peels was performed under different temperatures to produce biochar that was then examined as adsorbent in POME treatment. The pyrolysis generated 30.7-47.7 wt% yield of a dark biochar over a temperature ranging between 400 and 500 °C. The biochar contained no sulphur and possessed a hard texture, low volatile content (≤34 wt%), and high amounts of fixed carbon (≥72 wt%), showing durability in terms of high resistance to chemical reactions such as oxidation. The biochar showed a surface area of 105 m 2 /g and a porous structure containing mesopores, indicating its potential to provide many adsorption sites for use as an adsorbent. The use of the biochar as adsorbent to treat the POME showed a removal efficiency of up to 57% in reducing the concentration of biochemical oxygen demand (BOD), chemical oxygen demand COD, total suspended solid (TSS) and oil and grease (O&G) of POME to an acceptable level below the discharge standard. Our results indicate that pyrolysis shows promise as a technique to transform banana and orange peel into value-added biochar for use as adsorbent to treat POME. The recovery of biochar from fruit waste also shows advantage over traditional landfill approaches in disposing this waste. Copyright © 2018 Elsevier Ltd. All rights reserved.

Neutron reflectivity measurement of protein A-antibody complex at the solid-liquid interface.

PubMed

Mazzer, Alice R; Clifton, Luke A; Perevozchikova, Tatiana; Butler, Paul D; Roberts, Christopher J; Bracewell, Daniel G

2017-05-26

Chromatography is a ubiquitous unit operation in the purification of biopharmaceuticals yet few studies have addressed the biophysical characterisation of proteins at the solution-resin interface. Chromatography and other adsorption and desorption processes have been shown to induce protein aggregation which is undesirable in biopharmaceutical products. In order to advance understanding of how adsorption processes might impact protein stability, neutron reflectivity was used to characterise the structure of adsorbed immunoglobulin G (IgG) on model surfaces. In the first model system, IgG was adsorbed directly to silica and demonstrated a side-on orientation with high surface contact. A maximum dimension of 60Å in the surface normal direction and high density surface coverage were observed under pH 4.1 conditions. In chromatography buffers, pH was found to influence IgG packing density and orientation at the solid-liquid interface. In the second model system, which was designed to mimic an affinity chromatography surface, protein A was attached to a silica surface to produce a configuration representative of a porous glass chromatography resin. Interfacial structure was probed during sequential stages from ligand attachment, through to IgG binding and elution. Adsorbed IgG structures extended up to 250Å away from the surface and showed dependence on surface blocking strategies. The data was suggestive of two IgG molecules bound to protein A with a somewhat skewed orientation and close proximity to the silica surface. The findings provide insight into the orientation of adsorbed antibody structures under conditions encountered during chromatographic separations. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Adsorption of apo- and holo-tear lipocalin to a bovine Meibomian lipid film.

PubMed

Mudgil, Poonam; Millar, Thomas J

2008-04-01

Adsorption of apo- and holo-tear lipocalin (Tlc) to bovine Meibomian lipid film was studied. A Langmuir trough was used for these studies and the adsorption of protein was observed by recording changes in the pressure with time (pi-T profile). The films were photographed at different stages of adsorption by doping Meibomian lipids with a fluorescently tagged lipid. The results indicated that apo-Tlc adsorbed much more quickly than holo-Tlc to the Meibomian lipid film. Contrary to the expectation that holo-Tlc would release lipids to the surface and surface pressure would be higher, it was found that the surface pressure was higher with the adsorption of apo-Tlc to the surface. Photography of the films showed that apo- and holo-Tlc interacted differently with the Meibomian lipid layer. Adsorption of holo-Tlc resulted in big bright patches and adsorption of apo-Tlc resulted in many small patches along with the big patches. Both forms of Tlc produced a more stable film as indicated by decreased movement of the protein adsorbed films, and a higher maximum surface pressure upon compression of these films compared with Meibomian lipid films alone. Isocyles of apo-Tlc adsorbed films gave a higher surface pressure than that of holo-Tlc. From these results, it is concluded that both apo- and holo-Tlc adsorbed to the Meibomian lipid layer and the delivery of the lipids from Tlc to the outer lipid layer could not be detected by our techniques. Its scavenging role to remove lipids from the corneal surface and bind with them might be beneficial for increasing tear viscosity but whether those lipids are delivered to the outermost lipid layer still remains unclear.

Photoemission into water adsorbed on metals: Probing dissociative electron transfer using theory

NASA Astrophysics Data System (ADS)

Zhang, Yu; Whitten, J. L.

The photoinduced dissociation of water adsorbed on a silver nanoparticle is explored using theory to probe reaction pathways that produce hydrogen. Ab initio configuration theory is used to describe the systems. A formulation that allows excited electronic states embedded in a near continuum of lower energy states to be calculated accurately is described. Electron attachment of a photoemitted electron to adsorbed water can lead to the formation of H2 at a very low energy barrier with oxygen remaining on the Ag surface. A large energy barrier to form H2 plus adsorbed O is found for the ground state. The excited state has a much smaller barrier to OH stretch; however, to dissociate, the system must cross over from the excited state to the ground state potential energy surface. The cross over point is near the transition state for a ground state process. A characteristic feature of the excited state potential curve is an increase in energy in the early stages of OH stretch as the charge transfer state evolves from a state with considerable Rydberg character to one that has a typical OH antibonding molecular orbital. Another pathway releases a H atom leaving OH on the surface. Effects due to doping of a Ag nanoparticle with a K electron donor atom are compared with those caused by a Fermi level shift due to an applied potential. Results are also reported for electron transfer to a solvated lithium ion, Li(H2O) 6+, near the surface of a silver particle. A steering mechanism is found that involves the interaction of a hydridic hydrogen formed after electron transfer with an acidic hydrogen of a second solvated water molecule.

Modification of zeolite 4A for use as an adsorbent for glyphosate and as an antibacterial agent for water.

PubMed

Zavareh, Siamak; Farrokhzad, Zahra; Darvishi, Farshad

2018-07-15

The aim of this work was to design a low cost adsorbent for efficient and selective removal of glyphosate from water at neutral pH conditions. For this purpose, zeolite 4A, a locally abundant and cheap mineral material, was ion-exchanged with Cu 2+ to produce Cu-zeolite 4A. The FTIR results revealed that the modification has no important effect on chemical structure of zeolite 4A. After modification, highly crystalline zeolite 4A was converted to amorphous Cu-zeolite 4A according to XRD studies. The SEM images showed spherical-like particles with porous surfaces for Cu-zeolite 4A compared to cubic particles with smooth surfaces for zeolite 4A. Adsorption equilibrium data were well fitted with non-linear forms of Langmuir, Freundlich and Temkin isotherms. The maximum adsorption capacity for Cu-zeolite 4A was calculated to be 112.7 mg g -1 based on the Langmuir model. The adsorption of glyphosate by the modified adsorbent had fast kinetics fitted both pseudo-first-order and pseudo-second-order models. A mechanism based on chemical adsorption was proposed for the removal process. The modified adsorbent had a good selectivity to glyphosate over natural waters common cations and anions. It also showed desired regeneration ability as an important feature for practical uses. The potential use of the developed material as antibacterial agent for water disinfection filters was also investigated by MIC method. Relatively strong antibacterial activity was observed for Cu-zeolite 4A against Gram-positive and Gram-negative model bacteria while zeolite 4A had no antibacterial properties. No release of Cu 2+ to aqueous solutions was detected as unique feature of the developed material. Copyright © 2018 Elsevier Inc. All rights reserved.

Adsorbent catalytic nanoparticles and methods of using the same

DOEpatents

Slowing, Igor Ivan; Kandel, Kapil

2017-01-31

The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janke, Chris; Yatsandra, Oyola; Mayes, Richard

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

Activated Carbon-hydrogen based Continuous Sorption Cooling in Single Adsorbent Bed with LN2 Heat Sink

NASA Astrophysics Data System (ADS)

Koley, Susmita; Ghosh, Indranil

Quick and periodic inflow-outflow of adsorbate in an adsorbent column createsa differential temperature between the two ends of it, allowing for the generation of continuous sorption cooling in a single adsorbent tube. The concept has been proven experimentally and theoretically for near room temperature applications using activated carbon-nitrogen. The feasibility of generating continuous solid sorption cooling in a single adsorbent tube in the cryogenic domainhas been studied theoretically with a different adsorbent-adsorbate pair, namely, activated carbon-hydrogen. Precooling of gaseous hydrogen (before it enters the adsorbent column) and removal of the heat of adsorption has been achieved using liquid nitrogen. Theoretical estimation shows nearly 20 K temperature difference between the two ends under no load condition. Finally, parametric variations have been performed.

Recombination reactions of 5-eV O(3P) atoms on a MgF2 surface

NASA Technical Reports Server (NTRS)

Orient, O. J.; Chutjian, A.; Murad, E.

1990-01-01

A source of hyperthermal, ground-state, impurity-free, atomic oxygen of an energy variable in the range 2-100 eV has been developed. Experimental results are presented of emission spectra in the wavelength range 250-850 nm produced by collisions of 5-eV O(3P) atoms with adsorbed NO and CO molecules on a MgF2 surface.

Biomaterials and the U.S. Navy.

DTIC Science & Technology

1984-07-10

one lipid film adsorbed on a solid substrate ( Langmuir - Blodgett films). By this method diffusion of the lipid molecules could be studied. It was also...produces a potent emulsifier, allowing utilization of liquid hydrocarbons, such as decane, dodecane, tetradecane, or hexadecane. The strain also...efficiency 0 L -2%). Even though the tertiary structure of rhodopsin is known to a 7A -16- understand collagen. They prepared poly L proline, a single

Removal of heavy metal cations by biogenic magnetite nanoparticles produced in Fe(III)-reducing microbial enrichment cultures.

PubMed

Iwahori, Keisuke; Watanabe, Jun-ichi; Tani, Yukinori; Seyama, Haruhiko; Miyata, Naoyuki

2014-03-01

The biogenic magnetite nanoparticles presented here had a high capacity of adsorbing metal cations, which was approximately 30- to 40-fold greater than commercially available magnetite. These results suggest the potential application of microbial magnetite formation in the removal of toxic metal cations from water. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Room-temperature activation of methane and dry re-forming with CO 2 on Ni-CeO 2 (111) surfaces: Effect of Ce 3+ sites and metal–support interactions on C–H bond cleavage

DOE PAGES

Lustemberg, Pablo G.; Ramírez, Pedro J.; Liu, Zongyuan; ...

2016-10-27

The results of core-level photoemission indicate that Ni-CeO 2(111) surfaces with small or medium coverages of nickel are able to activate methane at 300 K, producing adsorbed CH x and CO x (x = 2, 3) groups. Calculations based on density functional theory predict a relatively low activation energy of 0.6–0.7 eV for the cleavage of the first C–H bond in the adsorbed methane molecule. Ni and O centers of ceria work in a cooperative way in the dissociation of the C–H bond at room temperature, where a low Ni loading is crucial for the catalyst activity and stability. Themore » strong electronic perturbations in the Ni nanoparticles produced by the ceria supports of varying natures, such as stoichiometric and reduced, result in a drastic change in their chemical properties toward methane adsorption and dissociation as well as the dry reforming of methane reaction. Lastly, the coverage of Ni has a drastic effect on the ability of the system to dissociate methane and catalyze the dry re-forming process.« less

Efficient purification of ethene by an ethane-trapping metal-organic framework

PubMed Central

Liao, Pei-Qin; Zhang, Wei-Xiong; Zhang, Jie-Peng; Chen, Xiao-Ming

2015-01-01

Separating ethene (C2H4) from ethane (C2H6) is of paramount importance and difficulty. Here we show that C2H4 can be efficiently purified by trapping the inert C2H6 in a judiciously designed metal-organic framework. Under ambient conditions, passing a typical cracked gas mixture (15:1 C2H4/C2H6) through 1 litre of this C2H6 selective adsorbent directly produces 56 litres of C2H4 with 99.95%+ purity (required by the C2H4 polymerization reactor) at the outlet, with a single breakthrough operation, while other C2H6 selective materials can only produce ca. ⩽ litre, and conventional C2H4 selective adsorbents require at least four adsorption–desorption cycles to achieve the same C2H4 purity. Single-crystal X-ray diffraction and computational simulation studies showed that the exceptional C2H6 selectivity arises from the proper positioning of multiple electronegative and electropositive functional groups on the ultramicroporous pore surface, which form multiple C–H···N hydrogen bonds with C2H6 instead of the more polar competitor C2H4. PMID:26510376

Room-temperature activation of methane and dry re-forming with CO 2 on Ni-CeO 2 (111) surfaces: Effect of Ce 3+ sites and metal–support interactions on C–H bond cleavage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lustemberg, Pablo G.; Ramírez, Pedro J.; Liu, Zongyuan

The results of core-level photoemission indicate that Ni-CeO 2(111) surfaces with small or medium coverages of nickel are able to activate methane at 300 K, producing adsorbed CH x and CO x (x = 2, 3) groups. Calculations based on density functional theory predict a relatively low activation energy of 0.6–0.7 eV for the cleavage of the first C–H bond in the adsorbed methane molecule. Ni and O centers of ceria work in a cooperative way in the dissociation of the C–H bond at room temperature, where a low Ni loading is crucial for the catalyst activity and stability. Themore » strong electronic perturbations in the Ni nanoparticles produced by the ceria supports of varying natures, such as stoichiometric and reduced, result in a drastic change in their chemical properties toward methane adsorption and dissociation as well as the dry reforming of methane reaction. Lastly, the coverage of Ni has a drastic effect on the ability of the system to dissociate methane and catalyze the dry re-forming process.« less

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

PubMed

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'.

Feasibility of mercury removal from simulated flue gas by activated chars made from poultry manures.

PubMed

Klasson, K Thomas; Lima, Isabel M; Boihem, Larry L; Wartelle, Lynda H

2010-12-01

Increased emphasis on reduction of mercury emissions from coal fired electric power plants has resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents for mercury removal. At the same time, the quantity of poultry manure generated each year is large and technologies that take advantage of the material should be explored. The purpose of the work was to obtain preliminary data to investigate if activated chars made from different poultry manures could adsorb mercury from simulated flue gas. In laboratory experiments, activated chars made from chicken cake and litter removed mercury from the gas as well as a commercial alternative. It was also found that acid-washing these chars after activation may improve pore structure but does not influence the mercury removal efficiency. Activated chars were also made from turkey cake and litter. These raw materials produced activated chars with similar pore structure as those made from chicken manure, but they did not adsorb mercury as well. Acid-washing the turkey manure-based chars improved their performance, but this step would add to the cost of production. Preliminary evaluations suggest that unwashed activated chars may cost as little as $0.95/kg to produce. Published by Elsevier Ltd.

Preparation of corncob grits as a carrier for immobilizing yeast cells for ethanol production.

PubMed

Lee, Sang-Eun; Lee, Choon Geun; Kang, Do Hyung; Lee, Hyeon-Yong; Jung, Kyung-Hwan

2012-12-01

In this study, DEAE-corncobs [delignified corncob grits derivatized with 2-(diethylamino)ethyl chloride hydrochloride (DEAE·HCl)] were prepared as a carrier to immobilize yeast (Saccharomyces cerevisiae) for ethanol production. The immobilized yeast cell reactor produced ethanol under optimized DEAE·HCl derivatization and adsorption conditions between yeast cells and the DEAE-corncobs. When delignified corncob grit (3.0 g) was derivatized with 0.5M DEAE·HCl, the yeast cell suspension (OD600 = 3.0) was adsorbed at >90% of the initial cell OD600. This amount of adsorbed yeast cells was estimated to be 5.36 mg-dry cells/g-DEAE corncobs. The Qmax (the maximum cell adsorption by the carrier) of the DEAE-corncobs was estimated to be 25.1 (mg/g), based on a Languir model biosorption isotherm experiment. When we conducted a batch culture with medium recycling using the immobilized yeast cells, the yeast cells on DEAE-corncobs produced ethanol gradually, according to glucose consumption, without cells detaching from the DEAE-corncobs. We observed under electron microscopy that the yeast cells grew on the surface and in the holes of the DEAEcorncobs. In a future study, DEAE-corncobs and the immobilized yeast cell reactor system will contribute to bioethanol production from biomass hydrolysates.

Sorbent-based Oxygen Production for Energy Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sethi, Vijay

Project DE-FE0024075 deals with the development of a moderate-temperature sorbent-based oxygen production technology. Sorbent-based oxygen production process utilizes oxygen-storage properties of Perovskites to (1) adsorb oxygen from air in a solid sorbent, and (2) release the adsorbed oxygen into a sweep gas such as CO 2 and/or steam for gasification systems or recycled flue gas for oxy-combustion systems. Pure oxygen can be produced by the use of vacuum instead of a sweep gas to affect the pressure swing. By developing more efficient and stable, higher sorption capacity, newer class of materials operating at moderate temperatures this process represents a majormore » advancement in air separation technology. Newly developed perovskite ceramic sorbent materials with order-disorder transition have a higher O 2 adsorption capacity, potentially 200 °C lower operating temperatures, and up to two orders of magnitude faster desorption rates than those used in earlier development efforts. The performance advancements afforded by the new materials lead to substantial savings in capital investment and operational costs. Cost of producing oxygen using sorbents could be as much as 26% lower than VPSA and about 13% lower than a large cryogenic air separation unit. Cost advantage against large cryogenic separation is limited because sorbent-based separation numbers up sorbent modules for achieving the larger capacity.« less

Removal of lead, cadmium, zinc, and copper from industrial wastewater by carbon developed from walnut, hazelnut, almond, pistachio shell, and apricot stone.

PubMed

Kazemipour, Maryam; Ansari, Mehdi; Tajrobehkar, Shabnam; Majdzadeh, Majdeh; Kermani, Hamed Reihani

2008-01-31

In this work, adsorption of copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) that exist in industrial wastewater onto the carbon produced from nutshells of walnut, hazelnut, pistachio, almond, and apricot stone has been investigated. All the agricultural shell or stone used were ground, sieved to a defined size range, and carbonized in an oven. Time and temperature of heating were optimized at 15 min and 800 degrees C, respectively, to reach maximum removal efficiency. Removal efficiency was optimized regarding to the initial pH, flow rate, and dose of adsorbent. The maximum removal occurred at pH 6-10, flow rate of 3 mL/min, and 0.1g of the adsorbent. Capacity of carbon sources for removing cations will be considerably decreased in the following times of passing through them. Results showed that the cations studied significantly can be removed by the carbon sources. Efficiency of carbon to remove the cations from real wastewater produced by copper industries was also studied. Finding showed that not only these cations can be removed considerably by the carbon sources noted above, but also removing efficiency are much more in the real samples. These results were in adoption to those obtained by standard mixture synthetic wastewater.

Method And Apparatus For Regenerating Nox Adsorbers

DOEpatents

Driscoll, J. Joshua; Endicott, Dennis L.; Faulkner, Stephen A.; Verkiel, Maarten

2006-03-28

Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

Method for modifying trigger level for adsorber regeneration

DOEpatents

Ruth, Michael J.; Cunningham, Michael J.

2010-05-25

A method for modifying a NO.sub.x adsorber regeneration triggering variable. Engine operating conditions are monitored until the regeneration triggering variable is met. The adsorber is regenerated and the adsorbtion efficiency of the adsorber is subsequently determined. The regeneration triggering variable is modified to correspond with the decline in adsorber efficiency. The adsorber efficiency may be determined using an empirically predetermined set of values or by using a pair of oxygen sensors to determine the oxygen response delay across the sensors.

Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

NASA Technical Reports Server (NTRS)

Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Iacomini, Christie; Paul, Heather, L.

2008-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (LCO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas is a significant heat transfer mechanism for the warming of the adsorbent bed because it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously. A NASA Small Business Innovative Research (SBIR) Phase 1 contract was performed to investigate condensing and icing as applied to MTSA to enable higher fidelity modeling and assess the impact of geometry variables on CIHX performance for future CIHX design optimization. Specifically, a design tool was created using analytical relations to explore the complex, interdependent design space of a condensing ice heat exchanger. Numerous variables were identified as having nontrivial contributions to performance such as hydraulic diameter, heat exchanger effectiveness, ventilation gas mass flow rate and surface roughness. Using this tool, four test articles were designed and manufactured to map to a full MTSA subassembly (the adsorbent bed, the sublimation heat exchanger for cooling and the condensing ice heat exchanger for warming). The design mapping considered impacts due to CIHX geometry as well as subassembly impacts such as thermal mass and thermal resistance through the adsorbent bed. The test articles were tested at simulated PLSS ventilation loop temperature, moisture content and subambient pressure. Ice accumulation and melting were observed. Data and test observations were analyzed to identify drivers of the condensing ice heat exchanger performance. This paper will discuss the analytical models, the test article designs, and testing procedures. Testing issues will be discussed to better describe data and share lessons learned. Data analysis and subsequent conclusions will be presented.

Nanopore reactive adsorbents for the high-efficiency removal of waste species

DOEpatents

Yang, Arthur Jing-Min; Zhang, Yuehua

2005-01-04

A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g., metal, enzyme, etc., particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as ions, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

Biodegradable metal adsorbent synthesized by graft polymerization onto nonwoven cotton fabric

NASA Astrophysics Data System (ADS)

Sekine, Ayako; Seko, Noriaki; Tamada, Masao; Suzuki, Yoshio

2010-01-01

A fibrous adsorbent for Hg ions was synthesized by radiation-induced emulsion graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven cotton fabric and subsequent chemical modification. The optimal pre-irradiation dose for initiation of the graft polymerization of GMA, which minimized the effects of radiation damage on the mechanical strength of the nonwoven cotton fabric, was found to be 10 kGy. The GMA-grafted nonwoven cotton fabric was subsequently modified with ethylenediamine (EDA) or diethylenetriamine (DETA) to obtain a Hg adsorbent. The resulting amine-type adsorbents were evaluated for batch and continuous adsorption of Hg. In batch adsorption, the distribution coefficients of Hg reached 1.9×10 5 and 1.0×10 5 for EDA- and DETA-type adsorbents, respectively. A column packed with EDA-type adsorbent removed Hg from 1.8 ppm Hg solution at a space velocity of 100 h -1, which corresponds to 16,000 times the volume of the packed adsorbent. The adsorbed Hg on the EDA-type adsorbent could be completely eluted by 1 M HCl solution. A microbial oxidative degradation test revealed that the EDA-type adsorbent is biodegradable.

Hydride compressor

DOEpatents

Powell, James R.; Salzano, Francis J.

1978-01-01

Method of producing high energy pressurized gas working fluid power from a low energy, low temperature heat source, wherein the compression energy is gained by using the low energy heat source to desorb hydrogen gas from a metal hydride bed and the desorbed hydrogen for producing power is recycled to the bed, where it is re-adsorbed, with the recycling being powered by the low energy heat source. In one embodiment, the adsorption-desorption cycle provides a chemical compressor that is powered by the low energy heat source, and the compressor is connected to a regenerative gas turbine having a high energy, high temperature heat source with the recycling being powered by the low energy heat source.

A molecular investigation of adsorption onto mineral pigments

NASA Astrophysics Data System (ADS)

Ninness, Brian J.

Pigment suspensions are important in several processes such as ceramics, paints, inks, and coatings. In the wet state, pigments are combined with a variety of chemical species such as polymers, surfactants, and polyelectrolytes which produce a complex colloidal system. The adsorption, desorption, and redistribution of these species at the pigment-aqueous solution interface can have an impact on the behavior in both the wet state or its final dried state. The goal of this work is to establish a molecular picture of the adsorption properties of these pigmented systems. A novel in situ infrared technique has been developed which allows the detection of adsorbed surface species on pigment particles in an aqueous environment. The technique involves the use of a polymeric binder to anchor the colloidal pigment particles to the surface of an internal reflection element (IRE). The binder only weakly perturbs about 25% of the reactive surface sites (hydroxyl groups) on silica. The reaction of succinic anhydride with an aminosilanized silica surface has been quantified using this technique. The adsorption dynamics of the cationic surfactant cetyltrimethylammonium bromide (C16TAB) at the TiO2-aqueous solution interface has been investigated using Fourier transform infrared-attenuated total reflection spectroscopy (FTIR-ATR) and electrokinetic analysis. At low bulk concentrations, C16TAB is shown to adsorb as isolated islands with a "defective" bilayer structure. Anionic probe molecules are shown to effectively "tune" the adsorbed surfactant microstructure. The results indicate that the structure of the adsorbed surfactant layer, and not the amount of adsorbed surfactant, dictates the subsequent adsorption behavior of the system. Atomic Layer Deposition is used to deposit a TiO2 layer onto the surfaces of silica and kaolin pigments. The process involves the cyclic reaction sequence of the vapors of TiCl4 and H2O. Three complete deposition cycles are needed before the surfaces of the modified pigments are dominated by the presence of TiO2. The modified kaolin pigments display increased dispersion stability as compared to the parent kaolin. The electrokinetic behavior of the modified kaolin is shown to be identical to that of pure TiO2 pigments.

Structural, electronic and optical properties of CO adsorbed on the defective anatase TiO2 (101) surface; a DFT study

NASA Astrophysics Data System (ADS)

Rafique, Muhammad; Shuai, Yong; Hassan, Muhammad

2017-08-01

This paper illustrates the study of stable structural, electronic and optical properties of carbon mono oxide (CO) molecule adsorbed on pure anatase TiO2 (101) surface and CO molecule adsorbed on defective anatase TiO2 (101) surface containing oxygen (O) atom subsurface vacancy using first-principles study calculations based on density functional theory (DFT) method. A foreign molecule CO was added in the interstitial space of anatase TiO2 (101) surface. It was observed that, adsorption of CO molecule is not favorable on pure anatase TiO2 (101) surface, however adsorption process is improved when subsurface contains O atom vacancy defect. In case of anatase TiO2 (101) surface containing subsurface vacancy, adsorption process is exothermic, resulting in stable structures. The adsorption energies calculated for CO molecules adsorbed at O2c site, at defect site and at Ti5c site of anatase surface containing subsurface O vacancy are 0.16 eV (at O2c), 0.32 eV (at defect site) and 0.43 eV (at Ti5c) site. DOS and PDOS plots are calculated for all the structures. Results indicated that CO molecule adsorption introduces surface states at the Fermi energy level (EF) as shown in partial density of states (PDOS) plots. The dielectric matrix and absorption coefficient (α) for defective anatase TiO2 (101) surface, CO adsorbed at O2c site, at defect site and at Ti5C site of anatase TiO2 (101) surface containing O atom subsurface vacancy has been calculated within the random phase approximation (RPA) using VASP (Vienna ab-initio simulation package) code. It was observed that upon CO adsorption at defective anatase surface, real and imaginary dielectric function peaks were shifted towards lower energy level and a small absorption peak was observed at 1.1 eV energy level which is not present in case of defective anatase (101) surface. CO adsorption produces a red shift in the absorption spectrum of anatase TiO2 (101) surface containing subsurface O atom vacancy.

Effect of urea and glycerol on the adsorption of ribonuclease A at the air-water interface.

PubMed

Hüsecken, Anne K; Evers, Florian; Czeslik, Claus; Tolan, Metin

2010-08-17

This study reports on the influence of nonionic cosolvents on the interfacial structure of ribonuclease A (RNase) adsorbed at the air-water interface. We applied X-ray reflectometry to obtain detailed volume fraction profiles of the adsorbed layers and to follow the effect of glycerol and urea on the adsorbate structure as a function of cosolvent concentration. Under all conditions studied, the adsorbed RNase layer maintains its compact shape, and the adsorbed RNase molecules adopt a flat-on orientation at the interface. Both kosmotropic glycerol and chaotropic urea exert profound effects on the adsorbate: The surface excess decreases linearly with glycerol content and is also reduced at low urea concentration. However, at high urea concentration, parts of the adsorbed layer are dehydrated and become exposed to air. The electron density and volume fraction profiles of the adsorbed protein provide clear evidence that these effects are ruled by different mechanisms.

Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

DOEpatents

Gaffney, T.R.; Golden, T.C.; Mayorga, S.G.; Brzozowski, J.R.; Taylor, F.W.

1999-06-29

A pressure swing adsorption process for absorbing CO[sub 2] from a gaseous mixture containing CO[sub 2] comprises introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100 C and 500 C to adsorb CO[sub 2] to provide a CO[sub 2] laden alumina adsorbent and a CO[sub 2] depleted gaseous mixture and contacting the CO[sub 2] laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO[sub 2] from the CO[sub 2] laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100 C and 600 C, is not degraded by high concentrations of water under process operating conditions. 1 fig.

Microengineering in cardiovascular research: new developments and translational applications.

PubMed

Chan, Juliana M; Wong, Keith H K; Richards, Arthur Mark; Drum, Chester L

2015-04-01

Microfluidic, cellular co-cultures that approximate macro-scale biology are important tools for refining the in vitro study of organ-level function and disease. In recent years, advances in technical fabrication and biological integration have provided new insights into biological phenomena, improved diagnostic measurements, and made major steps towards de novo tissue creation. Here we review applications of these technologies specific to the cardiovascular field, emphasizing three general categories of use: reductionist vascular models, tissue-engineered vascular models, and point-of-care diagnostics. With continued progress in the ability to purposefully control microscale environments, the detailed study of both primary and cultured cells may find new relevance in the general cardiovascular research community. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

On the radiation tolerance of SU-8, a new material for gaseous microstructure radiation detector fabrication

NASA Astrophysics Data System (ADS)

Key, M. J.; Cindro, V.; Lozano, M.

2004-12-01

SU-8 photosensitive epoxy resin was developed for the fabrication of high-aspect ratio microstructures in MEMS and microengineering applications, and has potential for use in the construction of novel gaseous micropattern radiation detectors. However, little is known of the behaviour of the cured material under irradiation. Mechanical properties of SU-8 film have been measured as a function of neutron exposure and compared with Kapton ® polyimide and Mylar ® PET polyester films, materials routinely used in gaseous radiation detectors, to asses the suitability of SU-8 based microstructures for gaseous detector applications. After exposure to a reactor core neutron fluence of 7.5×10 18 n cm -2, the new material showed a high level of resistance to radiation damage, comparable to Kapton film.

Engineering three-dimensional cardiac microtissues for potential drug screening applications.

PubMed

Wang, L; Huang, G; Sha, B; Wang, S; Han, Y L; Wu, J; Li, Y; Du, Y; Lu, T J; Xu, F

2014-01-01

Heart disease is one of the major global health issues. Despite rapid advances in cardiac tissue engineering, limited successful strategies have been achieved to cure cardiovascular diseases. This situation is mainly due to poor understanding of the mechanism of diverse heart diseases and unavailability of effective in vitro heart tissue models for cardiovascular drug screening. With the development of microengineering technologies, three-dimensional (3D) cardiac microtissue (CMT) models, mimicking 3D architectural microenvironment of native heart tissues, have been developed. The engineered 3D CMT models hold greater potential to be used for assessing effective drugs candidates than traditional two-dimensional cardiomyocyte culture models. This review discusses the development of 3D CMT models and highlights their potential applications for high-throughput screening of cardiovascular drug candidates.

New integrated silicon-PDMS process for compliant micro-mechanisms

NASA Astrophysics Data System (ADS)

Haouas, Wissem; Dahmouche, Redwan; Agnus, Joël; Le Fort-Piat, Nadine; Laurent, Guillaume J.

2017-12-01

Polydimethylsiloxane (PDMS) elastomers are used for many applications, such as microfluidics and micro-engineering. This paper presents a new process of integrating soft elastomers into a silicon structure without any assembly steps. The novelty of this process is the use of only one deep reactive ion etch (DRIE) instead of two or more as developed in previous works. Thus, this fabrication process allows the use of elastomers that are usually not compatible with some fabrication processes. Compliant flexures with different interference shapes have been designed, simulated, fabricated, and characterized for generic use and notably for micro-robot joints and compliant micro-systems. The experimental results show that the 400 μm  ×  400 μm cross-sectional area samples can be bended more than 60\\circ without delamination.

Metal-Induced Production of a Novel Bioadsorbent Exopolysaccharide in a Native Rhodotorula mucilaginosa from the Mexican Northeastern Region.

PubMed

Garza-Gonzalez, Maria Teresa; Gonzalez Garza, Maria Teresa; Barboza Perez, Daniel; Vazquez Rodriguez, Augusto; Garcia-Gutierrez, Domingo Ixcoatl; Zarate, Xristo; Cantú Cardenas, Maria Elena; Urraca-Botello, Ludwing Ilytch; Lopez-Chuken, Ulrico Javier; Trevino-Torres, Alberto Ludovico; Cerino-Córdoba, Felipe de Jesus; Medina-Ruiz, Pavel; Villarreal-Chiu, Juan Francisco; Morones-Ramirez, Jose Ruben

2016-01-01

There is a current need to develop low-cost strategies to degrade and eliminate industrially used colorants discharged into the environment. Colorants discharged into natural water streams pose various threats, including: toxicity, degradation of aesthetics and inhibiting sunlight penetration into aquatic ecosystems. Dyes and colorants usually have complex aromatic molecular structures, which make them very stable and difficult to degrade and eliminate by conventional water treatment systems. The results in this work demonstrated that heavy metal-resistant Rhodotorula mucilaginosa strain UANL-001L isolated from the northeast region of Mexico produce an exopolysaccharide (EPS), during growth, which has colorant adsorption potential. The EPS produced was purified by precipitation and dialysis and was then physically and chemically characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and chemical elemental analysis. Here, the ability of the purified EPS produced to adsorb methylene blue (MB), which served as a model colorant, is studied. MB adsorption by the EPS is found to follow Langmuir Adsorption Isotherm kinetics at 25°C. Further, by calculating the Langmuir constant the adsorption capabilities of the EPS produced by the Rhodotorula mucilaginosa strain UANL-001L is compared to that of other adsorbents, both, microbially produced and from agroindustrial waste. The total adsorption capacity of the EPS, from the Rhodotorula mucilaginosa strain UANL-001L, was found to be two-fold greater than the best bioadsorbents reported in the literature. Finally, apart from determining which heavy metals stimulated EPS production in the strain, the optimal conditions of pH, heavy metal concentration, and rate of agitation of the growing culture for EPS production, was determined. The EPS reported here has the potential of aiding in the efficient removal of colorants both in water treatment plants and in situ in natural water streams.

Metal-Induced Production of a Novel Bioadsorbent Exopolysaccharide in a Native Rhodotorula mucilaginosa from the Mexican Northeastern Region

PubMed Central

Vazquez Rodriguez, Augusto; Garcia-Gutierrez, Domingo Ixcoatl; Zarate, Xristo; Cantú Cardenas, Maria Elena; Urraca-Botello, Ludwing Ilytch; Lopez-Chuken, Ulrico Javier; Trevino-Torres, Alberto Ludovico; Cerino-Córdoba, Felipe de Jesus; Medina-Ruiz, Pavel; Villarreal-Chiu, Juan Francisco; Morones-Ramirez, Jose Ruben

2016-01-01

There is a current need to develop low-cost strategies to degrade and eliminate industrially used colorants discharged into the environment. Colorants discharged into natural water streams pose various threats, including: toxicity, degradation of aesthetics and inhibiting sunlight penetration into aquatic ecosystems. Dyes and colorants usually have complex aromatic molecular structures, which make them very stable and difficult to degrade and eliminate by conventional water treatment systems. The results in this work demonstrated that heavy metal-resistant Rhodotorula mucilaginosa strain UANL-001L isolated from the northeast region of Mexico produce an exopolysaccharide (EPS), during growth, which has colorant adsorption potential. The EPS produced was purified by precipitation and dialysis and was then physically and chemically characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and chemical elemental analysis. Here, the ability of the purified EPS produced to adsorb methylene blue (MB), which served as a model colorant, is studied. MB adsorption by the EPS is found to follow Langmuir Adsorption Isotherm kinetics at 25°C. Further, by calculating the Langmuir constant the adsorption capabilities of the EPS produced by the Rhodotorula mucilaginosa strain UANL-001L is compared to that of other adsorbents, both, microbially produced and from agroindustrial waste. The total adsorption capacity of the EPS, from the Rhodotorula mucilaginosa strain UANL-001L, was found to be two-fold greater than the best bioadsorbents reported in the literature. Finally, apart from determining which heavy metals stimulated EPS production in the strain, the optimal conditions of pH, heavy metal concentration, and rate of agitation of the growing culture for EPS production, was determined. The EPS reported here has the potential of aiding in the efficient removal of colorants both in water treatment plants and in situ in natural water streams. PMID:26828867

Combination of rice husk and coconut shell activated adsorbent to adsorb Pb(II) ionic metal and it’s analysis using solid-phase spectrophotometry (sps)

NASA Astrophysics Data System (ADS)

Rohmah, D. N.; Saputro, S.; Masykuri, M.; Mahardiani, L.

2018-03-01

The purpose of this research was to know the effect and determine the mass comparation which most effective combination between rice husk and coconut shell activated adsorbent to adsorb Pb (II) ion using SPS method. This research used experimental method. Technique to collecting this datas of this research is carried out by several stages, which are: (1) carbonization of rice husk and coconut shell adsorbent using muffle furnace at a temperature of 350°C for an hour; (2) activation of the rice husk and coconut shell adsorbent using NaOH 1N and ZnCl2 15% activator; (3) contacting the adsorbent of rice husk and coconut shell activated adsorbent with liquid waste simulation of Pb(II) using variation comparison of rice husk and coconut shell, 1:0; 0:1; 1:1; 2:1; 1:2; (4) analysis of Pb(II) using Solid-Phase Spectrophotometry (SPS); (5) characterization of combination rice husk and coconut shell activated adsorbent using FTIR. The result of this research show that the combined effect of combination rice husk and coconut shell activated adsorbent can increase the ability of the adsorbent to absorb Pb(II) ion then the optimum adsorbent mass ratio required for absorbing 20 mL of Pb(II) ion with a concentration of 49.99 µg/L is a ratio of 2:1 with the absorption level of 97,06%Solid-Phase Spectrophotometry (SPS) is an effective method in the level of µg/L, be marked with the Limit of Detection (LOD) of 0.03 µg/L.

An eco-friendly approach for heavy metal adsorbent regeneration using CO2-responsive molecular octopus.

PubMed

Bai, Yu; Liang, Yen Nan; Hu, Xiao

2017-10-01

Perennial problems of adsorption in wastewater treatment include adsorbent recycling, generation of waste sludge and secondary pollution because harmful concentrated acids, bases or strong chelators are often used for adsorbent regeneration and adsorbate recovery. We report, for the first time, an eco-friendly regeneration concept demonstrated with a CO 2 -responsive octopus-like polymeric adsorbent. Various heavy metals can be scavenged at very high Q e by such adsorbent through coordination. Most importantly, the rapid and complete regeneration of the adsorbent and recovery of the heavy metal ions can be readily achieved by CO 2 bubbling within a few minutes under mild conditions, i.e., room temperature and atmospheric pressure. The adsorbent can then be restored to its adsorptive state and reused upon removal of CO 2 by simply bubbling another gas. This eco-friendly, effective, ultra-fast and repeatable CO 2 -triggered regeneration process using CO 2 -responsive adsorbent with versatile structure, morphology or form can be incorporated into a sustainable closed-loop wastewater treatment process to solve the perennial problems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of adsorbents in transdermal matrix patches on the release and the physical state of ethinyl estradiol and levonorgestrel.

PubMed

Schulz, Martin; Fussnegger, Bernhard; Bodmeier, Roland

2011-02-01

The drug release from medium molecular weight polyisobutene patches containing adsorbates (drug content: 0.2% ethinyl estradiol, 1.0% levonorgestrel; adsorbent content: 20%, w/w) increased in the order of no adsorbent

Removal of arsenic from water using nano adsorbents and challenges: A review.

PubMed

Lata, Sneh; Samadder, S R

2016-01-15

Many researchers have used nanoparticles as adsorbents to remove water pollutants including arsenic after modifying the properties of nanoparticles by improving reactivity, biocompatibility, stability, charge density, multi-functionalities, and dispersibility. For arsenic removal, nano adsorbents emerged as the potential alternatives to existing conventional technologies. The present study critically reviewed the past and current available information on the potential of nano adsorbents for arsenic removal from contaminated water and the challenges involved in that. The study discussed the separation and regeneration techniques of nano adsorbents and the performance thereof. The study evaluated the adsorption efficiency of the various nanoparticles based on size of nanoparticles, types of nano adsorbents, method of synthesis, separation and regeneration of the nano adsorbents. The study found that more studies are required on suitable holding materials for the nano adsorbents to improve the permeability and to make the technology applicable at the field condition. The study will help the readers to choose suitable nanomaterials and to take up further research required for arsenic removal using nano adsorbents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of Feedstock and Pyrolysis Temperature on Biochar Adsorption of Ammonium and Nitrate

PubMed Central

Gai, Xiapu; Wang, Hongyuan; Liu, Jian; Zhai, Limei; Liu, Shen; Ren, Tianzhi; Liu, Hongbin

2014-01-01

Biochar produced by pyrolysis of biomass can be used to counter nitrogen (N) pollution. The present study investigated the effects of feedstock and temperature on characteristics of biochars and their adsorption ability for ammonium N (NH4 +-N) and nitrate N (NO3 −-N). Twelve biochars were produced from wheat-straw (W-BC), corn-straw (C-BC) and peanut-shell (P-BC) at pyrolysis temperatures of 400, 500, 600 and 700°C. Biochar physical and chemical properties were determined and the biochars were used for N sorption experiments. The results showed that biochar yield and contents of N, hydrogen and oxygen decreased as pyrolysis temperature increased from 400°C to 700°C, whereas contents of ash, pH and carbon increased with greater pyrolysis temperature. All biochars could sorb substantial amounts of NH4 +-N, and the sorption characteristics were well fitted to the Freundlich isotherm model. The ability of biochars to adsorb NH4 +-N followed: C-BC>P-BC>W-BC, and the adsorption amount decreased with higher pyrolysis temperature. The ability of C-BC to sorb NH4 +-N was the highest because it had the largest cation exchange capacity (CEC) among all biochars (e.g., C-BC400 with a CEC of 38.3 cmol kg−1 adsorbed 2.3 mg NH4 +-N g−1 in solutions with 50 mg NH4 + L−1). Compared with NH4 +-N, none of NO3 −-N was adsorbed to biochars at different NO3 − concentrations. Instead, some NO3 −-N was even released from the biochar materials. We conclude that biochars can be used under conditions where NH4 +-N (or NH3) pollution is a concern, but further research is needed in terms of applying biochars to reduce NO3 −-N pollution. PMID:25469875

Dissecting the steps of CO2 reduction: 2. The interaction of CO and CO2 with Pd/γ-Al2O3: an in situ FTIR study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szanyi, Janos; Kwak, Ja Hun

2014-08-07

Alumina supported Pd catalysts with metal loadings of 0.5, 2.5 and 10 wt% were investigated by in situ FTIR spectroscopy in order to understand the nature of adsorbed species formed during their exposure to CO2 and CO. Exposing the annealed samples to CO2 at 295 K resulted in the formation of alumina support-bound surface species only: linear adsorbed CO2, bidentate carbonates and bicarbonates. Room temperature exposure of all three samples to CO produced IR features characteristic of both ionic and metallic Pd, as well as bands we observed upon CO2 adsorption (alumina support-bound species). Low temperature (100 K) adsorption ofmore » CO on the three samples provided information about the state of Pd after oxidation and reduction. Oxidized samples contained exclusively ionic Pd, while mostly metallic Pd was present in the reduced samples. Subsequent annealing of the CO-saturated samples revealed the facile (low temperature) reduction of PdOx species by adsorbed CO. This process was evidenced by the variations in IR bands characteristic of ionic and metallic Pd-bound CO, as well as by the appearance of IR bands associated with CO2 adsorption as a function of annealing temperature. Samples containing oxidized Pd species (oxidized, annealed or reduced) always produced CO2 upon their exposure to CO, while CO2-related surface entities were observed on samples having only fully reduced (metallic) Pd. Acknowledgements: The catalyst preparation was supported by a Laboratory Directed Research and Development (LDRD) project. This work was supported by the US Department of Energy Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy. JHK also acknowledges the support of this work by the 2013 Research Fund of UNIST (Ulsan National Institute of Science and Technology, Ulsan, Korea).« less

Effects of feedstock and pyrolysis temperature on biochar adsorption of ammonium and nitrate.

PubMed

Gai, Xiapu; Wang, Hongyuan; Liu, Jian; Zhai, Limei; Liu, Shen; Ren, Tianzhi; Liu, Hongbin

2014-01-01

Biochar produced by pyrolysis of biomass can be used to counter nitrogen (N) pollution. The present study investigated the effects of feedstock and temperature on characteristics of biochars and their adsorption ability for ammonium N (NH4(+)-N) and nitrate N (NO3(-)-N). Twelve biochars were produced from wheat-straw (W-BC), corn-straw (C-BC) and peanut-shell (P-BC) at pyrolysis temperatures of 400, 500, 600 and 700°C. Biochar physical and chemical properties were determined and the biochars were used for N sorption experiments. The results showed that biochar yield and contents of N, hydrogen and oxygen decreased as pyrolysis temperature increased from 400°C to 700°C, whereas contents of ash, pH and carbon increased with greater pyrolysis temperature. All biochars could sorb substantial amounts of NH4(+)-N, and the sorption characteristics were well fitted to the Freundlich isotherm model. The ability of biochars to adsorb NH4(+)-N followed: C-BC>P-BC>W-BC, and the adsorption amount decreased with higher pyrolysis temperature. The ability of C-BC to sorb NH4(+)-N was the highest because it had the largest cation exchange capacity (CEC) among all biochars (e.g., C-BC400 with a CEC of 38.3 cmol kg(-1) adsorbed 2.3 mg NH4(+)-N g(-1) in solutions with 50 mg NH4(+) L(-1)). Compared with NH4(+)-N, none of NO3(-)-N was adsorbed to biochars at different NO3(-) concentrations. Instead, some NO3(-)-N was even released from the biochar materials. We conclude that biochars can be used under conditions where NH4(+)-N (or NH3) pollution is a concern, but further research is needed in terms of applying biochars to reduce NO3(-)-N pollution.

Laboratory Measurements of Oxygen Gas Release from Basaltic Minerals Exposed to UV- Radiation: Implications for the Viking Gas Exchange Experiments

NASA Astrophysics Data System (ADS)

Hurowitz, J. A.; Yen, A. S.

2007-12-01

The biology experiments onboard the Viking Landers determined that the Martian soils at Chryse and Utopia Planitia contain an unknown chemical compound of a highly oxidizing nature. The Gas Exchange Experiments (GEx) demonstrated that the humidification of a 1-cc Martian soil sample resulted in the production of as much as 790 nanomoles of oxygen gas. Yen et al. (2000) have provided experimental evidence that superoxide radicals can be generated on plagioclase feldspar (labradorite) grain surfaces by exposure to ultraviolet (UV) light in the presence of oxygen gas. Adsorbed superoxide radicals are thought to react readily with water vapor, and produce oxygen gas in quantities sufficient to explain the Viking GEx results. Direct evidence for the formation of oxygen gas, however, was not provided in the experiments of Yen et al (2000). Accordingly, the motivation of this study is to determine whether superoxide radicals adsorbed on labradorite surfaces are capable of producing oxygen gas upon exposure to water vapor. We have constructed an experimental apparatus that is capable of monitoring oxygen gas release from basaltic mineral powders that have been exposed to UV-radiation under Martian atmospheric pressure conditions. The apparatus consists of a stainless-steel vacuum chamber with a UV- transparent window where sample radiation exposures are performed. The vacuum chamber has multiple valved ports for injection of gases and water vapor. The vacuum chamber is connected via a precision leak valve to a quadrupole mass spectrometer, which measures changes in the composition of the headspace gases over our mineral samples. We will report on the results of our experiments, which are aimed at detecting and quantifying oxygen gas release from UV-exposed basaltic mineral samples using this new experimental facility. These results will further constrain whether superoxide ions adsorbed on mineral surfaces provide a viable explanation for the Viking GEx results, which have been of considerable controversy in the roughly three decades since the measurements were first made.

Adsorption of water and butanol in silicalite-1 film studied with in situ attenuated total reflectance-Fourier transform infrared spectroscopy.

PubMed

Farzaneh, Amirfarrokh; Zhou, Ming; Potapova, Elisaveta; Bacsik, Zoltán; Ohlin, Lindsay; Holmgren, Allan; Hedlund, Jonas; Grahn, Mattias

2015-05-05

Biobutanol produced by, e.g., acetone-butanol-ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35-120 °C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.

SFG study of the ethanol in an acidic medium--Pt(110) interface: effects of the alcohol concentration.

PubMed

Gomes, Janaina F; Busson, Bertrand; Tadjeddine, Abderrahmane

2006-03-23

Ethanol in an acidic solution-Pt(110) interface was studied by SFG spectroscopy (between 1820 and 2325 cm(-1)) to explore primarily the effects of the alcohol concentration. Stretching bands of H-Pt (ca. 1970 or 2050 cm(-1)) and CO (ca. 1980 and 2040 cm(-1)) species, produced by the ethanol oxidation, were detected during the adsorption and oxidation of 0-1 mol L(-1) ethanol in a 0.1 mol L(-1) HClO(4) solution on the electrode surface. Hydrogen and CO coadsorb stably on Pt(110) between 0.05 and 0.15 V in ethanol-containing solutions. In this potential range, the blue shift of the hydrogen resonance (ca. 80 cm(-1)) reveals a weakening of the hydrogen bonding between adsorbed hydrogen and water molecules in the double layer. After the hydrogen desorption (0.15 V), the formation of compact CO islands, depending on the ethanol concentration, lifts the Pt(110) surface reconstruction. In ethanol-free solution, the surface remains reconstructed. The lower-frequency CO band is assigned to the CO species adsorbed on (1 x 2) reconstructed Pt(110) domains, having smaller local coverages, while the higher-frequency CO band is attributed to the close-packed CO species adsorbed on (1 x 1) patches. The reaction pathway forming CO(2) is less favored with increasing ethanol concentration.

Compact, Lightweight Adsorber and Sabatier Reactor for CO2 Capture and Reduction for Consumable and Propellant Production

NASA Technical Reports Server (NTRS)

Junaedi, Christian; Hawley, Kyle; Walsh, Dennis; Roychoudhury, Subir; Busby, Stacy A.; Abney, Morgan B.; Perry, Jay L.; Knox, James C.

2012-01-01

The utilization of CO2 to produce (or recycle) life support consumables, such as O2 and H2O, and to generate propellant fuels is an important aspect of NASA's concept for future, long duration planetary exploration. One potential approach is to capture and use CO2 from the Martian atmosphere to generate the consumables and propellant fuels. Precision Combustion, Inc. (PCI), with support from NASA, continues to develop its regenerable adsorber technology for capturing CO2 from gaseous atmospheres (for cabin atmosphere revitalization and in-situ resource utilization applications) and its Sabatier reactor for converting CO2 to methane and water. Both technologies are based on PCI's Microlith(R) substrates and have been demonstrated to reduce size, weight, and power consumption during CO2 capture and methanation process. For adsorber applications, the Microlith substrates offer a unique resistive heating capability that shows potential for short regeneration time and reduced power requirements compared to conventional systems. For the Sabatier applications, the combination of the Microlith substrates and durable catalyst coating permits efficient CO2 methanation that favors high reactant conversion, high selectivity, and durability. Results from performance testing at various operating conditions will be presented. An effort to optimize the Sabatier reactor and to develop a bench-top Sabatier Development Unit (SDU) will be discussed.

Remediation of anionic dye from aqueous system using bio-adsorbent prepared by microwave activation.

PubMed

Sharma, Arush; Sharma, Gaurav; Naushad, Mu; Ghfar, Ayman A; Pathania, Deepak

2018-04-01

The present study was attempted to ascertain the possible application of activated carbon as a cost-effective and eco-friendly adsorbent prepared via microwave-assisted chemical activation. The activated carbon was characterized using different techniques. The various adsorption parameters have been optimized to examine the viability of activated carbon as a plausible sorbent for the remediation of Congo red (CR) dye from the aquatic system. The equilibrium data adequately fitted to the Langmuir isotherm with better R 2 (0.994). The maximum adsorption capacity (q m ) of activated carbon was recorded to be 68.96 mg/g. Additionally, sorptional kinetic data were examined by reaction-based and diffusion-based models such as pseudo-first-order and pseudo-second-order equations, and Elovich, intra-particle diffusion, and Dumwald-Wagner models, respectively. The computed values of thermodynamic parameters such as free energy change (ΔG 0 ), enthalpy change (ΔH 0 ) and entropy change (ΔS 0 ) were recorded as -3.63, 42.47 and 152.07 J/mol K, respectively, at 30°C, which accounted for a favorable, spontaneous and endothermic process. The regeneration study emphasized that the percentage uptake declined from 90.35% to 83.45% after six cycles of testing. So, our findings implied that activated carbon produced from biomass must be cost-effectively used as an adsorbent for detoxifying the CR dye from industrial effluents.

Paper pulp-based adsorbents for the removal of pharmaceuticals from wastewater: A novel approach towards diversification.

PubMed

Oliveira, Gonçalo; Calisto, Vânia; Santos, Sérgio M; Otero, Marta; Esteves, Valdemar I

2018-08-01

In this work, two pulps, bleached (BP) and raw pulp (RP), derived from the paper production process, were used as precursors of non-activated and activated carbons (ACs). In the case of non-ACs, the production involved either pyrolysis or pyrolysis followed by acid washing. For ACs production, the pulps were impregnated with K 2 CO 3 or H 3 PO 4 , and then pyrolysed and acid washed. After production, the materials were physically and chemically characterized. Then, batch adsorption tests on the removal of two pharmaceuticals (the anti-epileptic carbamazepine (CBZ) and the antibiotic sulfamethoxazole (SMX)) from ultra-pure water and from Waste Water Treatment Plant (WWTP) effluents were performed. In ultra-pure water, non-ACs were not able to adsorb CBZ or SMX while ACs showed good adsorption capacities. In WWTP effluents, although ACs satisfactorily adsorbed CBZ and SMX, they showed lower adsorption capacities for the latter. Tests with WWTP effluents revealed that the best adsorption capacities were achieved by carbons produced from BP and activated with H 3 PO 4 : 92±19mgg -1 for CBZ and 13.0±0.6mgg -1 for SMX. These results indicate the potential of paper pulps as precursors for ACs that can be applied in wastewater treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

PubMed

Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

2015-01-23

Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts. Copyright © 2014 Elsevier B.V. All rights reserved.

A new hypothesis for fluidification of vocal-fold mucus: scintigraphic study.

PubMed

Costa, Milton Melciades Barbosa; Maliska, Carmelindo

2012-05-01

Our aim was to establish a new hypothesis for the fluidification of the mucus of the vocal folds, by using a scintigraphic method to analyze the relationship of the saliva from the oral and pharyngeal cavities to the mucosa of the laryngeal vestibule. We theorized that the saliva that is adsorbed on the oral and pharyngeal mucosa enters the larynx and is also adsorbed on its mucosa, as a natural layer, fluidizing the mucus of the vestibule wall. A saline solution of sodium pertechnetate (Na(99m)TcO(4)) with radioactivity of 1.0 mCi was sprayed in the oral cavity of seven healthy volunteers, who were instructed to chew a piece of apple for as long as possible without swallowing. The migration of the radioactive saliva was recorded by a gamma-chamber apparatus. We observed radioactivity in the laryngeal mucosa in six of the seven volunteers, who developed no complaints and no respiratory-defense reactions. The results for frequency were statistically significant (Mann-Whitney test, P=0.05). The results indicate that an increased volume of saliva enters the larynx and is adsorbed in its mucosa, producing mucus fluidification. This supports our alternative hypothesis to the unlikely concept that hydration by water ingestion is the factor responsible for reduction of the mucus viscosity of the vocal folds. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

FTMS studies of sputtered metal cluster ions (IV): size-selective effects in the chemistry of Fe{/n +} with NH3 and Pd{/n +} with D2 or C2H4

NASA Astrophysics Data System (ADS)

Irion, M. P.; Selinger, A.; Schnabel, P.

1991-03-01

Fe{/n +} and Pd{/n +} clusters up to n=19 and n=25, respectively, are produced in an external ion source by sputtering of the respective metal foils with Xe+ primary ions at 20 keV. They are transferred to the ICR cell of a home-built Fourier transform mass spectrometer, where they are thermalized to nearly room temperature and stored for several tens of seconds. During this time, their reactions with a gas leaked in at low level are studied. Thus in the presence of ammonia, most Fe{/n +} clusters react by simply adsorbing intact NH3 molecules. Only Fe{4/+} ions show dehydrogenation/adsorption to Fe4(NH){/m +} intermediates ( m=1, 2) that in a complex scheme go on adsorbing complete NH3 units. To clarify the reaction scheme, one has to isolate each species in the ion cell, which often requires the ejection of ions very close in mass. This led to the development of a special isolation technique that avoids the use of isotopically pure metal samples. Pd{n/+} cluster ions ( n=2...9) dehydrogenate C2H4 in general to yield Pd n (C2H2)+, yet Pd{6/+} appear totally unreactive. Towards D2, Pd{7/+} ions seem inert, whereas Pd{8/+} adsorb up to two molecules.

Laser-induced modification of graphene in the presence of ethanol on a graphene - substrate interface

NASA Astrophysics Data System (ADS)

Pivovarov, P. A.; Frolov, V. D.; Zavedeev, E. V.; Konov, V. I.

2017-12-01

We have studied the effect that the substitution of an organic substance (ethanol) for water adsorbate on a CVD graphene-SiO2/Si interface has on the laser-induced modification of graphene and graphene structures on the SiO2 film. Scanning probe microscopy has been used to analyse changes in the electronic properties of graphene structures on a hydrophilic substrate in the presence of ethanol and as a result of a laser-induced spatial redistribution of a water-alcohol adsorbate on the interface. It has been demonstrated experimentally that ethanol substitution for water adsorbate leads to an increase in the surface potential of the graphene, which is equivalent to a reduction in its work function with respect to the original level under normal conditions at a relative humidity of air from 30% to 60%. In the laser irradiation zone, we observe an additional increase in surface potential by 30-50 mV. Thus, ethanol makes it possible to tune the laser-induced electronic properties of graphene on a substrate. In addition, it has been shown that the intercalation of ethanol molecules leads to severe temporal instability of the physical properties of graphene structures produced by local laser irradiation. We have demonstrated the possibility of information ‘rewriting’ by low-intensity laser pulses in microregions with a changed surface potential in the presence of ethanol.

Adsorption of mercury from aqueous solutions using palm oil fuel ash as an adsorbent - batch studies

NASA Astrophysics Data System (ADS)

Imla Syafiqah, M. S.; Yussof, H. W.

2018-03-01

Palm oil fuel ash (POFA) is one of the most abundantly produced waste materials. POFA is widely used by the oil palm industry which was collected as ash from the burning of empty fruit bunches fiber (EFB) and palm oil kernel shells (POKS) in the boiler as fuel to generate electricity. Mercury adsorption was conducted in a batch process to study the effects of contact time, initial Hg(II) ion concentration, and temperature. In this study, POFA was prepared and used for the removal of mercury(II) ion from the aqueous phase. The effects of various parameters such as contact time (0- 360 min), temperature (15 – 45 °C) and initial Hg(II) ion concentration (1 – 5 mg/L) for the removal of Hg(II) ion were studied in a batch process. The surface characterization was examined by scanning electron microscopy (SEM) and particle size distribution analysis. From this study, it was found that the highest Hg(II) ion removal was 99.60 % at pH 7, contact time of 4 h, initial Hg(II) ion concentration of 1 mg/L, adsorbent dosage 0.25 g and agitation speed of 100 rpm. The results implied that POFA has the potential as a low-cost and environmental friendly adsorbent for the removal of mercury from aqueous solution.

Using microkinetic analysis to search for novel anhydrous formaldehyde production catalysts

NASA Astrophysics Data System (ADS)

Li, Han-Jung; Lausche, Adam C.; Peterson, Andrew A.; Hansen, Heine A.; Studt, Felix; Bligaard, Thomas

2015-11-01

Direct dehydrogenation of methanol to produce anhydrous formaldehyde is investigated using periodic density functional theory (DFT) and combining the microkinetic model to estimate rates and selectivities on stepped (211) surfaces under a desired reaction condition. Binding energies of reaction intermediates and transition state energies for each elementary reaction can be accurately scaled with CHO and OH binding energies as the only descriptors. Based on these two descriptors, a steady-state microkinetic model is constructed with a piecewise adsorbate-adsorbate interaction model that explicitly includes the effects of adsorbate coverage on the rates and selectivities as well as the volcano plots are obtained. Our results show that most of the stepped (211) pure-metallic surfaces such as Au, Pt, Pd, Rh, Ru, Ni, Fe, and Co are located in a region of low activity and selectivity toward CH2O production due to higher rate for CH2O dehydrogenation than CH2O desorption. The selectivities toward CH2O production on Zn, Cu, and Ag surfaces are located on the boundary between the high and low selectivity regions. To find suitable catalysts for anhydrous CH2O production, a large number of A3B-type transition metal alloys are screened based on their predicted rates and selectivities, as well as their estimated stabilities and prices. We finally propose several promising candidates for the dehydrogenation of CH3OH.

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

PubMed

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.

Enhanced removal of humic acid from aqueous solution by novel stabilized nano-amorphous calcium phosphate: Behaviors and mechanisms

NASA Astrophysics Data System (ADS)

Jiang, Ling; Li, Yiming; Shao, Yi; Zhang, Yong; Han, Ruiming; Li, Shiyin; Wei, Wei

2018-01-01

Stabilized nano-amorphous calcium phosphate (nACP) was prepared using polyethylene glycol as stabilizer to obtain a nanosized amorphous adsorbent. The produced nACP was evaluated by using XRD, FTIR, SEM and X-ray photoelectron spectroscopy (XPS). The sedimentation test demonstrated that nACP exhibited better stability than crystallized hydroxyapatite. The adsorption efficiency of the nACP material for aqueous humic acid (HA) was evaluated from the point of view of medium pH, adsorption time, temperature, and ionic strength, as well as the presences of metal ions. The results of the study showed very good adsorption performance towards aqueous HA. The Sips modeling results revealed that the stabilized nACP adsorbent had a considerably high adsorption capacity (248.3 mg/g) for HA at 298 K. The adsorption data fitted well into pseudo-second order and Elovich kinetic models. XPS analyses indicated that HA retention on nACP material might be due to the surface complexation reaction between oxygen-containing group and calcium of HA and nACP, respectively. Moreover, the HA adsorption capacity of nACP could still keep more than 86% after four adsorption-desorption cycles. By taking into account all results it was concluded that the nACP adsorbent leveraged its stability in combination with its high uptake capacity to offer a great promise for HA adsorption from water.

Novel adsorbent for DNA adsorption: Fe(3+)-attached sporopollenin particles embedded composite cryogels.

PubMed

Ceylan, Şeyda; Odabaşı, Mehmet

2013-12-01

The aim of this study is to prepare supermacroporous cryogels embedded with Fe(3+)-attached sporopollenin particles (Fe(3++)-ASPs) having large surface area for high DNA adsorption capacity. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic cryogel column embedded with Fe3+(+)-ASPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N´-methylene- bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for DNA adsorption studies. Firstly, Fe3+(+) ions were attached to the sporopollenin particles (SPs), then the supermacroporous PHEMA cryogel with embedded Fe(3++)-ASPs was produced by free radical polymerization using N,N,N´, N´-Tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as initiator/activator pair in an ice bath. Optimum conditions of adsorption experiments were performed at pH 6.0 (0.02 M Tris buffer containing 0.2 M NaCl), with flow rate of 0.5 mL/min, and at 5°C. The maximum amount of DNA adsorption from aqueous solution was very high (109 mg/g SPs) with initial concentration of 3 mg/mL. It was observed that DNA could be repeatedly adsorbed and desorbed with this composite cryogel without significant loss of adsorption capacity. As a result, higher amounts of DNA adsorbed these composite cryogels are expected to be good candidate for achieving higher removal of anti-DNA antibodies from systemic lupus erythematosus (SLE) patients plasma.

Study of novel mechano-chemical activation process of red mud to optimize nitrate removal from water.

PubMed

Alighardashi, A; Gharibi, H R; Raygan, Sh; Akbarzadeh, A

2016-01-01

Red mud (RM) is the industrial waste of alumina production and causes serious environmental risks. In this paper, a novel activation procedure for RM (mechano-chemical processing) is proposed in order to improve the nitrate adsorption from water. High-energy milling and acidification were selected as mechanical and chemical activation methods, respectively. Synthesized samples of adsorbent were produced considering two parameters of activation: acid concentrations and acidification time in two selected milling times. Optimization of the activation process was based on nitrate removal from a stock solution. Experimental data were analyzed with two-way analysis of variance and Kruskal-Wallis methods to verify and discover the accuracy and probable errors. Best conditions (acceptable removal percentage > 75) were 17.6% w/w for acid concentrate and 19.9 minutes for acidification time in 8 hours for milling time. A direct relationship between increase in nitrate removal and increasing the acid concentration and acidification time was observed. The adsorption isotherms were studied and compared with other nitrate adsorbents. Characterization tests (X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectrophotometry, dynamic light scattering, surface area analysis and scanning electron microscopy) were conducted for both raw and activated adsorbents. Results showed noticeable superiority in characteristics after activation: higher specific area and porosity, lower particle size and lower agglomeration in structure.

Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2016-05-03

A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Foam-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2015-06-02

Foam-based adsorbents and a related method of manufacture are provided. The foam-based adsorbents include polymer foam with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the foam-based adsorbents includes irradiating polymer foam, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Foam-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Milestone Report - Complete New Adsorbent Materials for Marine Testing to Demonstrate 4.5 g-U/kg Adsorbent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janke, Christopher James; Das, Sadananda; Oyola, Yatsandra

2014-08-01

This report describes work on the successful completion of Milestone M2FT-14OR03100115 (8/20/2014) entitled, “Complete new adsorbent materials for marine testing to demonstrate 4.5 g-U/kg adsorbent”. This effort is part of the Seawater Uranium Recovery Program, sponsored by the U.S. Department of Energy, Office of Nuclear Energy, and involved the development of new adsorbent materials at the Oak Ridge National Laboratory (ORNL) and marine testing at the Pacific Northwest National Laboratory (PNNL). ORNL has recently developed two new families of fiber adsorbents that have demonstrated uranium adsorption capacities greater than 4.5 g-U/kg adsorbent after marine testing at PNNL. One adsorbent wasmore » synthesized by radiation-induced graft polymerization of itaconic acid and acrylonitrile onto high surface area polyethylene fibers followed by amidoximation and base conditioning. This fiber showed a capacity of 4.6 g-U/kg adsorbent in marine testing at PNNL. The second adsorbent was prepared by atom-transfer radical polymerization of t-butyl acrylate and acrylonitrile onto halide-functionalized round fibers followed by amidoximation and base hydrolysis. This fiber demonstrated uranium adsorption capacity of 5.4 g-U/kg adsorbent in marine testing at PNNL.« less

Bioavailability of Carbon Nanomaterial-Adsorbed Polycyclic Aromatic Hydrocarbons to Pimphales promelas: Influence of Adsorbate Molecular Size and Configuration.

PubMed

Linard, Erica N; Apul, Onur G; Karanfil, Tanju; van den Hurk, Peter; Klaine, Stephen J

2017-08-15

Despite carbon nanomaterials' (CNMs) potential to alter the bioavailability of adsorbed contaminants, information characterizing the relationship between adsorption behavior and bioavailability of CNM-adsorbed contaminants is still limited. To investigate the influence of CNM morphology and organic contaminant (OC) physicochemical properties on this relationship, adsorption isotherms were generated for a suite of polycyclic aromatic hydrocarbons (PAHs) on multiwalled carbon nanotubes (MWCNTs) and exfoliated graphene (GN) in conjunction with determining the bioavailability of the adsorbed PAHs to Pimphales promelas using bile analysis via fluorescence spectroscopy. Although it appeared that GN adsorbed PAHs indiscriminately compared to MWCNTs, the subsequent bioavailability of GN-adsorbed PAHs was more sensitive to PAH morphology than MWCNTs. GN was effective at reducing bioavailability of linear PAHs by ∼70%, but had little impact on angular PAHs. MWCNTs were sensitive to molecular size, where bioavailability of two-ringed naphthalene was reduced by ∼80%, while bioavailability of the larger PAHs was reduced by less than 50%. Furthermore, the reduction in bioavailability of CNM-adsorbed PAHs was negatively correlated with the amount of CNM surface area covered by the adsorbed-PAHs. This study shows that the variability in bioavailability of CNM-adsorbed PAHs is largely driven by PAH size, configuration and surface area coverage.

Trimethylamine (fishy odor) adsorption by biomaterials: effect of fatty acids, alkanes, and aromatic compounds in waxes.

PubMed

Boraphech, Phattara; Thiravetyan, Paitip

2015-03-02

Thirteen plant leaf materials were selected to be applied as dried biomaterial adsorbents for polar gaseous trimethylamine (TMA) adsorption. Biomaterial adsorbents were efficient in adsorbing gaseous TMA up to 100% of total TMA (100 ppm) within 24 h. Sansevieria trifasciata is the most effective plant leaf material while Plerocarpus indicus was the least effective in TMA adsorption. Activated carbon (AC) was found to be lower potential adsorbent to adsorb TMA when compared to biomaterial adsorbents. As adsorption data, the Langmuir isotherm supported that the gaseous TMA adsorbed monolayer on the adsorbent surface and was followed pseudo-second order kinetic model. Wax extracted from plant leaf could also adsorb gaseous TMA up to 69% of total TMA within 24 h. Another 27-63% of TMA was adsorbed by cellulose and lignin that naturally occur in high amounts in plant leaf. Subsequently, the composition appearing in biomaterial wax showed a large quantity of short-chain fatty acids (≤C18) especially octadecanoic acid (C18), and short-chain alkanes (C12-C18) as well as total aromatic components dominated in the wax, which affected TMA adsorption. Hence, it has been demonstrated that plant biomaterial is a superior biosorbent for TMA removal.

Synthesis and Characterization Pectin-Carboxymethyl Chitosan crosslinked PEGDE as biosorbent of Pb(II) ion

NASA Astrophysics Data System (ADS)

Hastuti, Budi; Siswanta, Dwi; Mudasir; Triyono

2018-01-01

Pectin and chitosan are biodegradable polymers, potentially applied as a heavy metal adsorbents. Unfortunately both biosorbents pectin and chitosan have a weakness in acidic media. For this purpose required modified pectin and chitosan. The modified adsorben is intended to obtain a stable adsorbent and resistance under acid. The research was done by experimental method in laboratory. The stages of this research are the synthesis of carboxymethyl chitosan (CMC), synthesis of Pec-CMC-PEGDE film adsorbent, stabily test under acid, the characterization of active group using FTIR, stability characterization of Pec-CMC-PEGDE powder adsorbent using XRD, termo stability using DTA-TGA. The results of the research have shown that: pectin and CMC can be cross-linked using PEGDE crosslinking agent, the film adsorbent was stable under HCl 1 M, the film adsorbent have active group comprise of carboxylate and amine groups. The result of characterization using XRD, shows that the adsorbent is semi-crystalline. Base on termo stability, the film adsorbent Pec-CMC-PEGDE stable up to 600°C. The film can be applied as an adsobent of Pb (II) ion remediation. The optimum pH of pec-CMC-PEGDE in adsorbed of Pb(II) was reached at pH 5 with 99.99% absorbent adsorbed and of and adsorption capacity was 46.11 mg/g.

Chromium (VI) purification using pine sawdust in batch systems

NASA Astrophysics Data System (ADS)

Politi, Dorothea; Sidiras, Dimitris

2012-12-01

Pine sawdust, a waste generated in furniture industry, has been used as low-cost potential adsorbent. This low-cost adsorbent was used for the removal of chromium (VI) from an aqueous solution. The kinetics of adsorption and extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbent and adsorbate. The effect of hydrogen ion concentration, contact time, adsorbent dose and initial concentration of adsorbate on the uptake of chromium were studied in batch experiments. The adsorption data has been correlated with Lagergren - Eldridge pseudofirst order kinetic model. The efficiency of adsorbent material for the removal of Cr(VI) was found to be between 13.1 and 95.6%, respectively. These results depend on the conditions of pH, contact time, sawdust dose and Cr(VI) concentration.

Magnetic adsorbent constructed from the loading of amino functionalized Fe{sub 3}O{sub 4} on coordination complex modified polyoxometalates nanoparticle and its tetracycline adsorption removal property study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ou, Jinzhao; Mei, Mingliang; Xu, Xinxin, E-mail: xuxx@mail.neu.edu.cn

2016-06-15

A magnetic polyoxometalates based adsorbent has been synthesized successfully through the loading of amino functionalized Fe{sub 3}O{sub 4} (NH{sub 2}-Fe{sub 3}O{sub 4}) on nanoparticle of a coordination complex modified polyoxometalates (CC/POMNP). FTIR illustrate there exist intense hydrogen bonds between NH{sub 2}-Fe{sub 3}O{sub 4} and CC/POMNP, which keep the stability of this adsorbent. At room temperature, this adsorbent exhibits ferromagnetic character with saturation magnetization of 8.19 emu g{sup −1}, which provides prerequisite for fast magnetic separation. Water treatment experiment illustrates this POM based magnetic adsorbent exhibits high adsorption capacity on tetracycline. The adsorption process can be described well with Temkin model,more » which illustrates the interaction between adsorbent and tetracycline plays the dominated role in tetracycline removal. The rapid, high efficient tetracycline adsorption ability suggests this POM based magnetic adsorbent exhibits promising prospect in medical and agriculture waste water purification. A magnetic polyoxometalates based adsorbent, which exhibits excellent tetracycline adsorption removal property has been synthesized through the loading of NH{sub 2}-Fe{sub 3}O{sub 4} on coordination complex modified polyoxometalates - Graphical abstract: A magnetic polyoxometalates based adsorbent, which exhibits excellent tetracycline adsorption removal property has been synthesized through the loading of NH{sub 2}-Fe{sub 3}O{sub 4} on coordination complex modified polyoxometalate. Display Omitted - Highlights: • A POM based magnetic adsorbent was fabricated through the loading of NH{sub 2}-Fe{sub 3}O{sub 4} on POM nanoparticle. • This adsorbent possesses excellent tetracycline adsorption property. • Saturation magnetization value of this adsorbent is 8.19 emug−1, which is enough for magnetic separation.« less

Gas separation device based on electrical swing adsorption

DOEpatents

Judkins, Roddie R.; Burchell, Timothy D.

1999-10-26

A method and apparatus for separating one constituent, especially carbon dioxide, from a fluid mixture, such as natural gas. The fluid mixture flows through an adsorbent member having an affinity for molecules of the one constituent, the molecules being adsorbed on the adsorbent member. A voltage is applied to the adsorbent member, the voltage imparting a current flow which causes the molecules of the one constituent to be desorbed from the adsorbent member.

Explosive Destruction System’s Drum Filter. Part 1. Experimental Validation

DTIC Science & Technology

2011-06-01

test to quantify filtration performance for MEA. Being a relatively low vapor pressure chemical, MEA is strongly adsorbed by microporous adsorbents...DMMP and the nerve/HD agents I I that it simulates are strongly adsorbed by microporous adsorbents, loading on the adsorbent is relatively...is started, the challenge chemical is fed to the top of the test filter located in an insulated enclosure (9), which can be seen immediately to the

Activated carbon from leather shaving wastes and its application in removal of toxic materials.

PubMed

Kantarli, Ismail Cem; Yanik, Jale

2010-07-15

In this study, utilization of a solid waste as raw material for activated carbon production was investigated. For this purpose, activated carbons were produced from chromium and vegetable tanned leather shaving wastes by physical and chemical activation methods. A detailed analysis of the surface properties of the activated carbons including acidity, total surface area, extent of microporosity and mesoporosity was presented. The activated carbon produced from vegetable tanned leather shaving waste produced has a higher surface area and micropore volume than the activated carbon produced from chromium tanned leather shaving waste. The potential application of activated carbons obtained from vegetable tanned shavings as adsorbent for removal of water pollutants have been checked for phenol, methylene blue, and Cr(VI). Adsorption capacities of activated carbons were found to be comparable to that of activated carbons derived from biomass. 2010 Elsevier B.V. All rights reserved.

Method oil shale pollutant sorption/NO.sub.x reburning multi-pollutant control

DOEpatents

Boardman, Richard D [Idaho Falls, ID; Carrington, Robert A [Idaho Falls, ID

2008-06-10

A method of decreasing pollutants produced in a combustion process. The method comprises combusting coal in a combustion chamber to produce at least one pollutant selected from the group consisting of a nitrogen-containing pollutant, sulfuric acid, sulfur trioxide, carbonyl sulfide, carbon disulfide, chlorine, hydroiodic acid, iodine, hydrofluoric acid, fluorine, hydrobromic acid, bromine, phosphoric acid, phosphorous pentaoxide, elemental mercury, and mercuric chloride. Oil shale particles are introduced into the combustion chamber and are combusted to produce sorbent particulates and a reductant. The at least one pollutant is contacted with at least one of the sorbent particulates and the reductant to decrease an amount of the at least one pollutant in the combustion chamber. The reductant may chemically reduce the at least one pollutant to a benign species. The sorbent particulates may adsorb or absorb the at least one pollutant. A combustion chamber that produces decreased pollutants in a combustion process is also disclosed.

Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

DOEpatents

Gaffney, Thomas Richard; Golden, Timothy Christopher; Mayorga, Steven Gerard; Brzozowski, Jeffrey Richard; Taylor, Fred William

1999-01-01

A pressure swing adsorption process for absorbing CO.sub.2 from a gaseous mixture containing CO.sub.2 comprising introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100.degree. C. and 500.degree. C. to adsorb CO.sub.2 to provide a CO.sub.2 laden alumina adsorbent and a CO.sub.2 depleted gaseous mixture and contacting the CO.sub.2 laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO.sub.2 from the CO.sub.2 laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100.degree. C. and 600.degree. C., is not degraded by high concentrations of water under process operating conditions.

Recovery of nitrogen and light hydrocarbons from polyalkene purge gas

DOEpatents

Zwilling, Daniel Patrick; Golden, Timothy Christoph; Weist, Jr., Edward Landis; Ludwig, Keith Alan

2003-06-10

A method for the separation of a gas mixture comprises (a) obtaining a feed gas mixture comprising nitrogen and at least one hydrocarbon having two to six carbon atoms; (b) introducing the feed gas mixture at a temperature of about 60.degree. F. to about 105.degree. F. into an adsorbent bed containing adsorbent material which selectively adsorbs the hydrocarbon, and withdrawing from the adsorbent bed an effluent gas enriched in nitrogen; (c) discontinuing the flow of the feed gas mixture into the adsorbent bed and depressurizing the adsorbent bed by withdrawing depressurization gas therefrom; (d) purging the adsorbent bed by introducing a purge gas into the bed and withdrawing therefrom an effluent gas comprising the hydrocarbon, wherein the purge gas contains nitrogen at a concentration higher than that of the nitrogen in the feed gas mixture; (e) pressurizing the adsorbent bed by introducing pressurization gas into the bed; and (f) repeating (b) through (e) in a cyclic manner.

Adsorption characteristics of benzene on biosolid adsorbent and commercial activated carbons.

PubMed

Chiang, Hung-Lung; Lin, Kuo-Hsiung; Chen, Chih-Yu; Choa, Ching-Guan; Hwu, Ching-Shyung; Lai, Nina

2006-05-01

This study selected biosolids from a petrochemical waste-water treatment plant as the raw material. The sludge was immersed in 0.5-5 M of zinc chloride (ZnCl2) solutions and pyrolyzed at different temperatures and times. Results indicated that the 1-M ZnCl2-immersed biosolids pyrolyzed at 500 degrees C for 30 min could be reused and were optimal biosolid adsorbents for benzene adsorption. Pore volume distribution analysis indicated that the mesopore contributed more than the macropore and micropore in the biosolid adsorbent. The benzene adsorption capacity of the biosolid adsorbent was 65 and 55% of the G206 (granular-activated carbon) and BPL (coal-based activated carbon; Calgon, Carbon Corp.) activated carbons, respectively. Data from the adsorption and desorption cycles indicated that the benzene adsorption capacity of the biosolid adsorbent was insignificantly reduced compared with the first-run capacity of the adsorbent; therefore, the biosolid adsorbent could be reused as a commercial adsorbent, although its production cost is high.

Effects of pyrolysis temperature, time and leaf litter and powder coal ash addition on sludge-derived adsorbents for nitrogen oxide.

PubMed

Ren, Xiaoli; Liang, Baohong; Liu, Min; Xu, Xiaoyuan; Cui, Meihua

2012-12-01

The objective of this research was to seek a cost effective solution to prepare adsorbents for nitrogen oxide from surplus sludge. Leaf litter and powder coal ash were used as cheap and easily available additives. An adsorbent for nitrogen oxide was prepared by pyrolysis of dried sludge mixed with zinc chloride. Under optimum pyrolysis conditions of 375°C for 90 min and a zinc chloride content of 30%, the surface area of the adsorbent with leaf litter was 514.41 m(2)/g, the surface area of the adsorbent with powder coal ash was 432.34 m(2)/g, respectively, corresponding to an increase of 90.70% and 60.27% when compared to the adsorbent without the additives. The saturated adsorption quantity of the adsorbent with leaf litter reached 271 mg/g at 20°C. The results indicated that the sludge-derived adsorbent was quite promising for nitrogen oxide removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of activated carbon surface chemistry and pore structure on the adsorption of trace organic contaminants from aqueous solution

NASA Astrophysics Data System (ADS)

Li, Lei

The objectives were (1) to identify activated pore structure and surface chemistry characteristics that assure the effective removal of trace organic contaminants from aqueous-solution, and (2) to develop a procedure to predict the adsorption capacity of activated carbons from fundamental adsorbent and adsorbate properties. A matrix of activated carbon fibers (ACFs) (with three activation levels and four surface chemistry levels) and three commercially available granular activated carbons (GACs) served as the adsorbents. BET surface area, pore size distribution, elemental composition, point of zero charge and infrared spectroscopy data were obtained to characterize the adsorbents. The adsorption of relative hydrophilic methyl tertiary-butyl ether (MTBE) and relative hydrophobic trichloroethene (TCE) were conducted in both ultrapure water and Sacramento-San Joaquin Delta water. The results showed that an effective adsorbent for the removal of micropollutants from water requires (1) a large volume of micropores with widths that are about 1.5 times larger than the kinetic diameter of the target adsorbate, (2) a micropore size distribution that extends to widths that are approximately twice the kinetic diameter of the target adsorbate to prevent pore blockage by NOM, and (3) a hydrophobic pore surface chemistry with the sum of oxygen and nitrogen contents less than 2 to 3 mmol/g. A procedure based on the Polanyi Potential Theory (PPT) was developed to predict the adsorption capacities of activated carbons from fundamental adsorbent and adsorbate properties. A correlation between the coalescing factor for water adsorption and adsorbent oxygen content was developed. Based on this correlation, the PPT yielded reasonable estimates of aqueous phase adsorption capacities for both relatively polar and non-polar adsorbates on both relatively hydrophobic and hydrophilic activated carbons. With the developed procedure, the adsorption capacities of organic compounds that are partially miscible in water can be predicted from (1) N2 and CO2 adsorption isotherms of a given adsorbent, (2) the adsorbent oxygen content, and (3) the molar volume and parachor of the target adsorbate.

How to distinguish various components of the SHG signal recorded from the solid/liquid interface?

NASA Astrophysics Data System (ADS)

Gassin, Pierre-Marie; Martin-Gassin, Gaelle; Prelot, Benedicte; Zajac, Jerzy

2016-11-01

Second harmonic generation (SHG) may be an important tool to probe buried solid/liquid interfaces because of its inherent surface sensitivity. A detailed interpretation of dye adsorption onto Si-SiO2 wafer is not straightforward because both adsorbent and adsorbate contribute to the overall SHG signal. The polarization resolved SHG analysis points out that the adsorbent and adsorbate contributions are out of phase by π/2 in the present system. The surface nonlinear susceptibility χ(2) represents thus a complex tensor in which its real part is related to the adsorbent contribution and its imaginary part to the adsorbate one.

Closed end regeneration method

DOEpatents

Yang, Arthur Jing-Min; Zhang, Yuehua

2006-06-27

A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g. metal, enzyme, etc. particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as irons, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

Evaluation of selective composite cryogel for bromate removal from drinking water.

PubMed

Hajizadeh, Solmaz; Kirsebom, Harald; Galaev, Igor Y; Mattiasson, Bo

2010-06-01

Bromate, which is a potential carcinogen, should be removed from drinking water to levels of less than 10 microg/L. A chitosan-based molecularly imprinted polymer (MIP) and a sol-gel ion-exchange double hydrous oxide (Fe(2)O(3) x Al(2)O(3) x xH(2)O) adsorbent (inorganic adsorbent) were prepared for this purpose. The sorption behavior of each adsorbent including sorption kinetics, isotherms, effect of pH and selective sorption were investigated in detail. Sorption experimental results showed that the MIP adsorbents had better selectivity for bromate, even in the presence of high concentrations of nitrate, as compared to the inorganic adsorbent. It was found that pH does not affect the adsorption of bromate when using the inorganic adsorbent. Additionally, both adsorbents were immobilized in a polymeric cryogel inside plastic carriers to make them more practical for using in larger scale. Regeneration of the cryogels either containing MIP or inorganic adsorbents were carried out by 0.1 M NaOH and 0.1 M NaCl, respectively. It was found that the regenerated MIP and inorganic adsorbents could be used at least three and five times, respectively, without any loss in their sorption capacity.

New general pore size distribution model by classical thermodynamics application: Activated carbon

USGS Publications Warehouse

Lordgooei, M.; Rood, M.J.; Rostam-Abadi, M.

2001-01-01

A model is developed using classical thermodynamics to characterize pore size distributions (PSDs) of materials containing micropores and mesopores. The thermal equation of equilibrium adsorption (TEEA) is used to provide thermodynamic properties and relate the relative pore filling pressure of vapors to the characteristic pore energies of the adsorbent/adsorbate system for micropore sizes. Pore characteristic energies are calculated by averaging of interaction energies between adsorbate molecules and adsorbent pore walls as well as considering adsorbate-adsorbate interactions. A modified Kelvin equation is used to characterize mesopore sizes by considering variation of the adsorbate surface tension and by excluding the adsorbed film layer for the pore size. The modified-Kelvin equation provides similar pore filling pressures as predicted by density functional theory. Combination of these models provides a complete PSD of the adsorbent for the micropores and mesopores. The resulting PSD is compared with the PSDs from Jaroniec and Choma and Horvath and Kawazoe models as well as a first-order approximation model using Polanyi theory. The major importance of this model is its basis on classical thermodynamic properties, less simplifying assumptions in its derivation compared to other methods, and ease of use.