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Topic: Adsorption


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In the News (Tue 18 Jun 19)

  
  Adsorption lecture
Sorption, which includes both adsorption and absorption, is a general expression for a process in which a components moves from one phase to be accumulated in another, particularly for cases in which the second phase is solid.
Adsorption is a process in which matter is extracted from one phase and concentrated at the surface of a second - a surface phenomenon.
Adsorption reaction are normally exothermic, thus the extent of adsorption generally increases with decreasing temperature.
web.njit.edu /~hsieh/ene670/adsorptn.html   (1665 words)

  
 Adsorption Research Inc.   (Site not responding. Last check: 2007-10-07)
Adsorption is a process that uses special solids (called adsorbents) to remove substances from either gaseous or liquid mixtures.
The term "adsorption" was first coined in the late 19th century, but the process itself was not widely used until the 1940s and 50s when activated carbon was first used for municipal water treatment.
Adsorption is also used for recovery of certain constituents (solvents from air), preventing pollution, purifying materials that will react, and so on.
www.adsorption.com /publications.htm   (544 words)

  
 Adsorption - Biocrawler   (Site not responding. Last check: 2007-10-07)
In chemistry, adsorption of a substance is its concentration on a particular surface.
The adsorption of reactant/s to the catalyst surface creates a chemical bond, altering the electron density around the reactant molecule and allowing it to undergo reactions that would not normally be available to it.
The higher the rate of adsorption and the lower the rate of desorption, the greater the fraction of the available surface which will be covered by adsorbed material at equilibrium.
www.biocrawler.com /encyclopedia/Adsorption   (422 words)

  
 Adsorption - Wikipedia, the free encyclopedia
Adsorption is operative in most natural physical, biological, and chemical systems, and is widely used in industrial applications such as activated charcoal, synthetic resins and water purification.
Adsorption is an exothermic process because energy is liberated, therefore enthalpy is always negative.
Adsorption refrigeration and heat pump cycles rely on the adsorption of a refrigerant gas into an adsorbent at low pressure and subsequent desorption by heating.
en.wikipedia.org /wiki/Adsorption   (2711 words)

  
 Activated carbon, reactivation from Chemviron Carbon   (Site not responding. Last check: 2007-10-07)
Adsorption is the process where molecules are concentrated on the surface of the activated carbon.
The driving force for adsorption is the ratio of the partial pressure and the vapour pressure of the compound.
The driving force for adsorption is the ratio of the concentration to the solubility of the compound.
www.chemvironcarbon.com /carbon/definition/adsorption.htm   (259 words)

  
 Table of contents for Carbon adsorption
In the case of physical adsorption, the adsorbate is bound to the surface by relatively weak van der walls forces which are similar to the molecular forces of cohesion and are involved in the condensation of vapors into liquids.
The adsorption of a solute from a solution is usually determined by the porosity and the chemical nature of the adsorbent, the nature of the components of the solution, the concentration of the solution and its pH and the mutual solubility of the components in the solution.
The adsorption on a solid surface, the types of adsorption, the energetics of adsorption, the theories of adsorption and the adsorption isotherm equations such as the Langmuir equation, the BET equation, the Dubinin equation, Temkin equation and the Freundlich equation are the subject matter of Chapter 2.
www.loc.gov /catdir/toc/ecip052/2004024878.html   (5994 words)

  
 Adsorption
Adsorption is governed also by the interaction between the adsorbed molecules, which have the same origin.
The main aspects of the adsorption process is the bonding of the incoming molecule to the surface, its motion across it or to the interior (diffusion) and the evaporation (desorption).
Adsorption may require a particular orientation of the molecule with respect to the surface.
www.virginia.edu /ep/SurfaceScience/Adsorption.html   (1512 words)

  
 Adsorption of Contaminants with Organoclay
Adsorption phenomena are operative in most natural physical, biological, and chemical systems, and adsorption operations employing solids such as activated carbon and synthetic resins are used widely in industrial applications and for purification of waters and wastewater.
Adsorption is thus different from absorption, a process in which material transferred from one phase to another (e.g.
Physical adsorption is caused mainly by van der Waals forces and electrostatic forces between adsorbate molecules and the atoms which compose the adsorbent surface.
www.aquatechnologies.com /info_adsorption.htm   (423 words)

  
 Adsorption / Active Carbon - Lenntech
Adsorption is a process where a solid is used for removing a soluble substance from the water.
The activity level of adsorption is based on the concentration of substance in the water, the temperature and the polarity of the substance.
When a substance is attached to a surface is is called adsorption, is this case the substance is attached to the internal surface of active carbon.
www.lenntech.com /adsorption.htm   (886 words)

  
 Activated Carbon
Adsorption is the process by which Activated Carbon removes substances from water.
Defined, adsorption is "the collection of a substance onto the surface of adsorbent solids." It is a removal process where certain particles are bound to an adsorbent particle surface by either chemical or physical attraction.
Adsorption is often confused with Absorption, where the substance being collected or removed actually penetrates into the other solid (Reynolds&Richards, 1996).
ewr.cee.vt.edu /environmental/teach/wtprimer/carbon/sketcarb.html   (1292 words)

  
 Gas Adsorption
The constant c represents the relative strengths of adsorption to the surface and condensation of the pure adsorbate.
The BET isotherm predicts that the amount of adsorption increases indefinitely as the pressure is increased since there is no limit to the amount of condensation of the adsorbate.
The adsorption process is generally taken as completely reversible, but, under some conditions the isotherm may exhibit a different shape upon desorption as compared to absorption.
itl.chem.ufl.edu /4411L_f00/ads/ads_1.html   (3049 words)

  
 Adsorption: Theory, Modeling, and Analysis
Adsorption shows how to calculate mono- or multi-layer adsorption in the measurement of a G/L, G/S, or L/S isotherm; discusses the structure of an adsorbed layer, changes in free energy of surfaces, recent advances in rare-gas adsorption, supercritical region isotherms, hydrophobic solid—water interfaces, and more.
This fact is reflected in the titles of the chapters and the methods applied in discussing the problems of physical adsorption.
I aimed to prove that the problems of physical adsorption, in spite of the ramified research fields, have similar or identical roots.
www.polysurfacesbookstore.com /pages/3686.html   (297 words)

  
 2.3 Adsorption Kinetics - The Rate of Adsorption
The above equation indicates that the rate of adsorption is expected to be first order with regard to the partial pressure of the molecule in the gas phase above the surface.
It should be recognised that the activation energy for adsorption may itself be dependent upon the surface coverage, i.e.
For a discussion of some of the factors which determine the magnitude of the activation energy of adsorption you should see Section 2.4 which looks at the typical PE curve associated with various types of adsorption process.
www.chem.qmul.ac.uk /surfaces/scc/scat2_3.htm   (518 words)

  
 Adsorption   (Site not responding. Last check: 2007-10-07)
Adsorption, the binding of molecules or particles to a surface, must be distinguished from absorption, the filling of pores in a solid.
Although activated carbon is a magnificent material for adsorption, its fl color persists and adds a grey tinge if even trace amounts are left after treatment; however filter materials with fine pores remove carbon quite well.
Temperature effects on adsorption are profound, and measurements are usually at a constant temperature.
www.rpi.edu /dept/chem-eng/Biotech-Environ/Adsorb/adsorb.htm   (351 words)

  
 Adsorption Solutions | Home   (Site not responding. Last check: 2007-10-07)
We are an adsorption technology consulting company specializing in molecular sieve applications and mercury removal.
This is the use of a thermally regenerated adsorption unit to remove heavy hydrocarbons from natural gas to allow the downstream CO2 rejection membrane unit to perform as designed.
We know the adsorption products that are available and which ones can best be used for each application.
www.adsorptionsolutions.com   (216 words)

  
 4-43 Adsorption/ Absorption
In liquid adsorption, solutes concentrate at the surface of a sorbent, thereby reducing their concentration in the bulk liquid phase.
Adsorption mechanisms are generally categorized as either physical adsorption, chemisorption, or electrostatic adsorption.
Electrostatic adsorption involves the adsorption of ions through Coulombic forces, and is normally referred to as ion exchange, which is addressed separately in the ion exchange modules.
www.frtr.gov /matrix2/section4/4-44.html   (814 words)

  
 4.59 Vapor-Phase Carbon Adsorption (via CobWeb/3.1 planetlab2.cs.umd.edu)   (Site not responding. Last check: 2007-10-07)
Typical Vapor-Phase Carbon Adsorption System Vapor-phase carbon adsorption is a remediation technology in which pollutants are removed from air by physical adsorption onto activated carbon grains.
Factors that affect adsorption are temperature, type and pore size of the carbon, the type and concentration of the contaminant, residence time in the bed; and in gas phase adsorption, temperature and humidity.
Thus, it is often necessary to conduct adsorption tests with a particular contaminated stream on a variety of activated carbons from several manufacturers to identify a carbon that will be most effective for a particular application.
www.frtr.gov.cob-web.org:8888 /matrix2/section4/4-61.html   (1046 words)

  
 Type_Document_Title_Here
C, while the heat of adsorption for a component versus each of the two formulations of adsorbent is established as well.
The magnitude of the heat of adsorption on each of the two formulations are usually very different, for the higher activity formulation (strong adsorption, low capacity) invariably appearing to be the highest.
The latter means that the overall net heat of adsorption depends on the adsorbate distribution over the lower and the higher activity formulation and therefore on the total amount being adsorbed, i.e.
www.esselinkbv.com /simulation.html   (1506 words)

  
 Adsorption
The question whether the adsorption or desorption branch of a hysteretic isotherm should be taken for pore size analysis has been discussed for many decades.
Gas adsorption is a prominent method to obtain a comprehensive characterization of porous materials with respect to the specific surface area, pore size distribution and porosity.
It is advantageous to analyze zeolites with narrow micropores by using argon as the adsorptive at liquid argon temperature (87.3 K).
www.azonano.com /SearchResults.asp?AppKeyWord=Adsorption   (406 words)

  
 Adsorption Affinity
Before addressing toxic metals and organic compounds, however, we must be able to predict the amount of surface charge that can develop on a mineral surface, i.e., the surface acidity and electrolyte ion adsorption affinities.
We have developed such as a model based on classical thermodynamics, crystal structure, electrostatic theory, and Born solvation theory (Fig.
Similarly, the logarithm of the equilibrium constant for adsorption of the i-th monovalent ion on the k-th mineral surface is given by (Sahai and Sverjensky, 1997 a, b):
www.geology.wisc.edu /~sahai/AdsorptionAffinity.html   (404 words)

  
 Selective Adsorption Associates, Inc.
Selective Adsorption Associates, Inc. specializes in products, equipment, and systems that remove contaminants from gases and liquids.
We have 25 years of experience in adsorbent development and testing, adsorption system design, and technical service.
Adsorption is often the most efficient way to remove chemical contaminants from fluids, when contaminants are < 2,000 ppm and the goal is <10ppm, <1ppm, or < one part per billion or lower.
www.selectiveadsorption.com   (305 words)

  
 Phosphate adsorption on Titanium Oxide
The objective of this work is to understand the different mechanisms of phosphate adsorption on the titanium oxide and in general to understand the adsorption of different ions on a technologically important metal-oxide surface.
The increase in intensity of peak B and D is significant of an increase in density of states in the O 2p-Ti 3d hybridized valence band.
Phosphate adsorption on c.p.Ti plates from phosphoric acid was observed and characterized with AES, REELS and TPD.
www.unige.ch /gap-b/diplo/kerem/pads.html   (877 words)

  
 Adsorption | English | Dictionary & Translation by Babylon
Adsorption is a process that occurs when a liquid or gas (called adsorbate) accumulates on the surface of a solid or liquid (adsorbent), forming a molecular or atomic film (adsorbate).
adsorption, attraction of a gas or liquid to the surface of a solid, occlusion (Chemistry)
Adsorption to French Adsorption to Italian Adsorption to Spanish Adsorption to Dutch Adsorption to Portuguese Adsorption to German Adsorption to Russian Adsorption to Japanese Adsorption to Chinese (T) Adsorption to Chinese (S) Adsorption to Turkish Adsorption to Hebrew Adsorption to Additional Adsorption to Croatian Adsorption to Serbian Adsorption to Swedish
www.babylon.com /definition/Adsorption/English   (295 words)

  
 Ion exchange : adsorption
Adsorption consists of the binding of molecules to the surface of an adsorbent, whereas adsorption consists in the filling of the pores in the solid media.
The adsorption media can be operated in liquid or gas phases, in aqueous or solvent phases.
Adsorption is a key process for the extraction of impurities or valuable chemicals, the adsorbents can be from various origins (synthetic polymers or carbonaceous material).
www.novasep.com /Technologies/ion-adsorption.asp   (497 words)

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