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Topic: Desorption

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	Enantiospecific Desorption of Chiral Compounds from Chiral Cu(643) and Achiral Cu(111) Surfaces
		Desorption measurements were performed by heating the sample at a constant rate while the mass spectrometer monitored the species desorbing from the surface.
		Desorption experiments are conducted with the sample approximately 2-3 mm from the end of this aperture, and any desorption from the opposite side of the crystal is undetectable.
		In the case of the propylene oxides on the Cu(643) surfaces, the desorption peak at 222 K in Figure 6 is associated with desorption from the kinked steps while the peak at 154 K is associated with desorption from the (111) terraces.
	pubs.acs.org /cgi-bin/jcen?jacsat/124/i10/html/ja012182i.html (6375 words)

	Recirculation of desorption outlet for rotary concentrator - Patent 5788744
		In a disclosed embodiment of this invention, a portion of the desorption gas exhaust is recirculated.
		In a second embodiment, the desorption gas is recirculated to the inlet of the rotary concentrator as gas to be cleaned in the concentrator.
		Desorption gas inlet 42 is communicated to a heating system 44, which heats a source of desorption gas 46.
	www.freepatentsonline.com /5788744.html (1924 words)

	Low-Temperature Thermal Desorption (Site not responding. Last check: 2007-11-03)
		Low-Temperature Thermal Desorption (LTTD), also known as low-temperature thermal volatilization, thermal stripping, and soil roasting, is an ex-situ remedial technology that uses heat to physically separate petroleum hydrocarbons from excavated soils.
		In order for desorption of petroleum constituents to occur, most of the soil moisture must be evaporated in the desorber.
		The presence of metals in soil can have two implications: (1) limitations on disposal of the solid wastes generated by desorption, and (2) attention to air pollution control regulations that limit the amount of metals that may be released in stack emissions.
	www.epa.gov /swerust1/cat/lttd.htm (3218 words)

	Short Path Thermal Desorption System Description
		The Thermal Desorption Unit sits directly on top of the GC injection port of most GC's, where it is utilized for the direct desorption of both volatile and semi-volatile samples into the GC injection port and column.
		The desorption tube will pass through the opening in the middle plate of the Desorption Unit base to position the desorption tube in proper alignment with the GC injection port and the normally open desorption block assembly.
		When ready for analysis the GLT desorption tubes are fitted with a syringe needle and attached to the Desorption Unit.
	www.sisweb.com /sptd/sptddesc.htm (1934 words)

	Renju Zacharia, PhDThesis, FU Berlin
		These thermal desorption experiments are carried out with the objective of understanding three different aspects about carbon surfaces: First, to determine the interlayer cohesive energy of graphite; second, to study the oxidation of porous carbon surfaces; and finally to determine the catalytic performance of carbon surfaces for oxidative dehydrogenation (ODH) of ethylbenzene.
		Thermal desorption of the four polyaromatic hydrocarbon molecules: benzene, naphthalene, coronene and ovalene, from the basal planes of graphite are used to obtain their activation energies for desorption, pre-exponential factors and orders of desorption.
		The pre-exponential frequency factors of desorption are found to be considerably larger in comparison to those of smaller molecules, which qualitatively is concluded to arise from large differences in the vibrational partition functions of the PAH molecules in the adsorbed and transition states.
	www.diss.fu-berlin.de /2004/162/indexe.html (687 words)

	Thermal Desorption (Site not responding. Last check: 2007-11-03)
		Thermal Desorption or low temperature thermal desorption (LTTD), also known as low temperature thermal volatilization, thermal stripping, and soil roasting, is an ex-situ remedial technology that uses heat to physically separate petroleum hydrocarbons from excavated soils.
		Thermal desorbers are designed to heat soils to temperatures sufficient to cause constituents to volatilize and desorb (physically separate) from the soil.
		Desorption units are available in a variety of process configurations including rotary desorbers, asphalt plant aggregate dryers, thermal screws, and conveyor furnaces.
	www.remtech1.com /thermal_desorption.htm (404 words)

	Thermal Desorption Tubes by Camsco
		In past years Camsco’s Thermal Desorption Tubes were almost exclusively used in conjunction with GC and GC/MS for the detection of several chemical warfare agents.
		Camsco’s Thermal Desorption Tubes are used in an expanding variety of industries including, transportation safety, detector research, Hazmat and civil defense.
		Camsco’s Thermal Desorption Tubes and related products have grown to include Thermal Desorption Tubes for a variety of clients including those involved in environmental monitoring, industrial hygiene, breath analysis, development of flavors and fragrances, fire detection and manufacturing quality control.
	www.camsco.com (483 words)

	Aging Effects on the Sorption-Desorption Characteristics of Anthropogenic Organic Compounds in Soil -- Sharer et al. 32 ...
		Desorption kinetics of ethylene dibromide, chlorobenzene, atrazine, and 2,4-D on Capac A-horizon soil after aging periods of 1 d, 30 d, and 14 mo. Desorption is expressed as percent of the expected amount assuming complete reversibility.
		Desorption and mineralization kinetics of phenanthrene and chrysene in contaminated soils.
		Oliver, B.G. Desorption of chlorinated hydrocarbons from spiked and anthropogenically contaminated sediments.
	jeq.scijournals.org /cgi/content/full/32/4/1385 (3396 words)

	A Citizen's Guide to Thermal Desorption
		Thermal desorption is an innovative treatment technology that treats soils contaminated with hazardous wastes by heating soils to temperatures of 200-1,000°F so that contaminants with low boiling points will vaporize (turn into gas) and, consequently, separate from the soil.
		Typical thermal desorption systems (Figure 1) consist of three components: the pre-treatment and material handling system, the desorption unit, and the post-treatment system for both the gas (vaporized contaminants) and the solid (remaining soil).
		The function of the desorption unit is to heat the contaminated soil to a sufficient temperature for a sufficient period to dry it and vaporize the contaminants from the soil.
	www.p2pays.org /ref/07/06191 (1400 words)

	Pulsed Desorption Kinetics
		Desorption phenomena are most commonly studied using temperature programmed desorption (TPD), a technique in which the sample is cleaned, dosed with the gas of interest, and then heated, preferably with a linear temperature ramp, while observing the desorption signal for the relevant species using a mass spectrometer.
		This is consistent with an activation energy for desorption which depends on coverage, an effect commonly seen for CO on Pt.
		A second explanation for the non-exponential decay is that the mass spectrometer is receiving CO desorption signal from Pt that is at a lower temperature than 383 K, i.e.
	www.cstl.nist.gov /div836/836.04/SensorProj/Desorption.html (1311 words)

	Thermal Desorption & Thermal Extraction – CDS
		Thermal desorption is a technique that encompasses two functions, sample collection / concentration and transfer to a detector.
		Thermal desorption uses heat instead of solvent extraction to release organic compounds from the adsorbent and transfer all of the collected sample to a gas chromatograph for analysis, eliminating:
		When samples are collected in areas of high humidity, two stage sorbent trapping and thermal desorption effectively eliminate water interferences and enhance analysis of polar compounds in the sample stream.
	www.cdsanalytical.com /products/thermwhy.htm (252 words)

	2.6 The Desorption Process
		The last of these options is the desorption process.
		In the absence of decomposition the desorbing species will generally be the same as that originally adsorbed but this is not necessarily always the case.
		One property of an adsorbed molecule that is intimately related to the desorption kinetics is the surface residence time - this is the average time that a molecule will spend on the surface under a given set of conditions (in particular, for a specified surface temperature) before it desorbs into the gas phase.
	www.chem.qmul.ac.uk /surfaces/scc/scat2_6.htm (487 words)

	Agilent \| Thermal Desorption
		Thermal desorption is a widely used technique for extracting and isolating volatile and semivolatile compounds from various matrices.
		Single-sample unit for the analysis of industry-standard thermal desorption tubes, canisters, or bags.
		Thermal desorption is really a constellation of techniques that are used to extract and concentrate volatiles from a complex matrix prior to GC or GC/MS analysis.
	www.chem.agilent.com /scripts/generic.asp?lpage=8419&indcol=Y&prodcol=Y (605 words)

	Residence Time Effects on Arsenate Adsorption/Desorption Mechanisms on Goethite -- O'Reilly et al. 65 (1): 67 -- Soil ...
		Structural parameters for As desorption from goethite in the presence of phosphate.
		Kinetics of cadmium and cobalt desorption from iron and manganese oxides.
		Reaction kinetics of the adsorption and desorption of nickel, zinc and cadmium by goethite.
	soil.scijournals.org /cgi/content/full/65/1/67 (5623 words)

	TPD Fundamentals
		The temperatures are in Kelvin and the rate of desorption is shown on an arbitrary scale.
		Theoretical models of TPD are used to interpret the TPD spectra with the goal of determining themodynamic and kinetic parameters.
		If the desorption process requies that two adsorbed molecules must collide on the surface before one molecule of species A is desorbed, then the order or power of the rate law is expected to be n = 2.
	www.sci.wsu.edu /idea/TPD/index.html (867 words)

	Incident Beam Diffraction in Electron-Stimulated Desorption
		If we assume that stimulated desorption begins by the excitation or ionization of an electron in the solid, the ESD rate will be a maximum when the charge distribution of the incident electron significantly overlaps that of the target electron.
		The desorption intensity I(k) has the symmetry of the location of the interaction which led to desorption, which can be the desorbate for direct excitations, or a different site for indirect excitations (caused by secondary electrons or energy transport).
		However, it is qualitatively evident from Figure 3.20 that the use of DESD for structural analysis of the initial desorbate bonding should use data acquired as close to threshold as possible, to minimize the indirect component.
	www.emsl.pnl.gov /docs/annual_reports/csd/annual_report1999/1578b_3i.html (1167 words)

	Thermal Desorption
		It is important to note that thermal desorption does not to destroy organics.
		Thermal desorption for mercury-contaminated waste is generally not appropriate.
		All the equipment used during the project, including the thermal desorption unit, was transported to the site by barge.
	www.cpeo.org /techtree/ttdescript/thedesop.htm (578 words)

	Laser Induced Thermal Desorption
		However, the desorption amount is changing more rapidly than Gaussian from 1 to 0 at x is around 20 (it depends on the laser power, and x= the distance from the laser center.
		With this sharp desorption resolution and the focusing of laser beam, we can use LITD to get a good spatial relution on the metal surface experiment.
		The desorption happens within 20 nano seconds, and the relaxation time to get the thermal equilibrium by the surface molecule is in the order of pico seconds.
	www.ph.utexas.edu /~jerryk/research3.html (435 words)

	HSL - Publications - MDHS
		Laboratory method using porous polymer adsorption tubes and thermal desorption with gas chromatographic analysis.
		A method using diffusive samplers, qualitative on-site colorimetric analysis and quantitative cold vapour atomic absorption spectrometry in the laboratory.
		Laboratory method using pumped solid sorbent tubes, solvent desorption and gas chromatography.
	www.hsl.gov.uk /publications/mdhs_list.htm (1113 words)

	Time Dependence of Chlorobenzene Sorption/Desorption by Soils -- Sharer et al. 67 (6): 1740 -- Soil Science Society of ...
		Desorption of chlorobenzene (CB) from four soils after 24 h and 14 mo of CB-soil contact time.
		Adsorption and desorption hysteresis of pahs in surface sediment.
		Desorption kinetics of neutral hydrophobic organic compounds from field-contaminated sediment.
	soil.scijournals.org /cgi/content/full/67/6/1740 (3213 words)

	2000 Progress Report - EFFECTS OF SOIL/SEDIMENT ORGANIC MATTER ON THE DESORPTION, BIOAVAILABILITY, SEQUESTRATION, AND ...
		A common measure of bioavailability is the microbial mineralization profile; this is based on the assumption that unavailability to microorganisms implies unavailability to higher life forms.
		Similar trends were found for the desorption profiles, suggesting that desorption is the rate-limiting step in the system.
		The extent of desorption was greater than the extent of mineralization, as expected since degradation of phenanthrene results in reactive metabolites, cell biomass, and carbon dioxide.
	es.epa.gov /ncer/fellow/progress/99/soderstromsa00.html (1008 words)

	Hazardous Waste - Thermal Desorption Systems (1 0f 3) (Site not responding. Last check: 2007-11-03)
		Thermal desorption has been employed widely as a means of removing contaminants from solid waste streams.
		Thermal desorption has also been employed or is proposed to be used in a number of processes where some contaminant degradation occurs within the thermal desorption unit, followed by combustion of the off gases.
		The process is based on thermal desorption and uses a flash pyrolysis technique to decompose organic and/or inorganic solid hazardous and solid waste, followed by combustion.
	oztoxics.org /research/3000_hcbweb/library/gov_fed/appteck/thermal.html (2693 words)

	4-25 Thermal Desorption
		Thermal desorption is a physical separation process and is not designed to destroy organics.
		In addition to identifying soil contaminants and their concentrations, information necessary for engineering thermal systems to specific applications include soil moisture content and classification, determination of boiling points for various compounds to be removed, and treatability tests to determine the efficiency of thermal desorption for removing various contaminants at various temperatures and residence times.
		All ex situ soil thermal treatment systems employ similar feed systems consisting of a screening device to separate and remove materials greater than 5 centimeters (2 inches), a belt conveyor to move the screened soil from the screen to the first thermal treatment chamber, and a weight belt to measure soil mass.
	www.frtr.gov /matrix2/section4/4-26.html (2036 words)

	TAB #13: Soil Remediation: Low Temperature Thermal Desorption
		Low Temperature Thermal Desorption (LTTD) is an Ex-Situ means of physically separating volatile and semi-volatile organic contaminants from soils.
		Soils contaminated with hydrocarbons are excavated and delivered to the thermal desorption unit.
		The maximum concentration of hydrocarbons in the soil that can be treated by a thermal desorption device depends on the gas flow through the device, the oxygen content of the purge gas, and the type of hydrocarbon product present.
	www.on.ec.gc.ca /pollution/ecnpd/tabs/tab13-e.html (930 words)

	Desorption-Assisted Sun Diver Missions
		We discuss desorption, as it has a rigorous experimental base in the regime of interesting temperatures.
		V imparted by desorption at perihelion and the second from (b), ordinary solar photon acceleration on the outward-bound leg, once the desorped layer is gone, leaving a reflecting sail.
		Using mass loss for thrust is not a new idea, but it is new to apply this idea, together with a powerful microwave beam, to both heat and push a sail.
	www.physics.uci.edu /faculty/STAEF2002Desorp.html (3046 words)

	2000 Progress Report - RAPID CHARACTERIZATION OF LONG-TERM HOC DESORPTION FROM SOILS AND SEDIMENTS BY SUPERHEATED WATER ... (Site not responding. Last check: 2007-11-03)
		The goal of this research is to develop a superheated water extraction methodology to rapidly characterize the long-term desorption of hydrophobic organic contaminants from soils and sediments.
		A technique for rapidly predicting the long-term HOC desorption behavior in a contaminated soil or sediment would be invaluable for engineers and scientists planning remediation schemes and/or grappling with difficult alternative remediation endpoint decisions.
		Apparent desorption energies were confirmed by Arrhenius modeling of isothermal desorption rates at temperatures between 25 and 150°C. Phenanthrene desorption rates and extents were also measured at 25°C for the corresponding contaminated geosorbents for up to 455 days.
	es.epa.gov /ncer/fellow/progress/97/johnsonma00.html (392 words)

	Assessment of Bioavailability of Soil-Sorbed Atrazine -- Park et al. 69 (6): 3288 -- Applied and Environmental ...
		desorption into bulk solution is not a prerequisite for biodegradation.
		Abiotic atrazine desorption data and regression (R-) lines from a three-site desorption model for sorbents.
		Particle-scale investigation of PAH desorption kinetics and thermodynamics from sediment.
	aem.asm.org /cgi/content/full/69/6/3288 (5574 words)

	EMSL: Mass Spec: Laser Desorption - Ion Trap
		The content of the EMSL website is available to any browser, but for the best experience we highly recommend you upgrade to a standards-compliant browser such as the lastest version of Firefox, Internet Explorer (Windows only), or Opera.
		Several major modifications have been made to adapt this commercial instrument to laser desorption studies of solid samples.
		This ITMS has been modified to allow laser desorption into the trapping volume and laser access to the trapped ions.
	www.emsl.pnl.gov /capabs/instruments/instrument_pages/1033.shtml (893 words)

	Low Temperature Thermal Desorption
		Low Temperature Thermal Desorption (LTTD) is a treatment technology which removes contaminants from solid media (e.g., soils) by volatilizing them with heat, but without combustion of the media.
		LTTD has been widely used in treating petroleum contaminated wastes and is being used increasingly in the cleanup of manufactured gas plant (MGP) wastes and hazardous constituents, notably chlorinated solvents and pesticides.
		The Low Temperature Thermal Desorption (LTTD) Task Group (regulators from California, Florida, Illinois, New Jersey, New York and EPA) developed a preliminary plan to provide a set of composite LTTD regulatory requirements for all participating states.
	www.westgov.org /wga/publicat/lttdweb.htm (5828 words)

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