1、Designation: D2652 11Standard Terminology Relating toActivated Carbon1This standard is issued under the fixed designation D2652; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses ind
2、icates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This terminology covers terms particularly related toactivated carbon and encompasses finished products, applica-tions, and testing procedures.1.2 When any of t
3、he definitions in this terminology arequoted or published out of context, editorially insert thelimiting phrase “in activated carbon” after the dash followingthe term to properly limit the field of application of the termand definition.2. Significance and Use2.1 This terminology ensures that terms p
4、eculiar to acti-vated carbon are adequately defined so that other standards inwhich such terms are used can be understood and interpretedproperly.2.2 This terminology is useful to those who are not conver-sant with the terms related to activated carbon. However, it isalso a ready reference for those
5、 directly associated withactivated carbon to resolve differences and ensure commonal-ity of usage, particularly in the preparation ofASTM standards.2.3 Although this terminology is intended to promote uni-formity in the usage of terms related to activated carbon, it cannever be complete because new
6、terms are constantly arising.The existence of this terminology does not preclude the use ormisuse of any term in another context.3. Terminologyabrasion resistancethe property of a particle to resistattrition or wearing away by friction.absorptiona process in which fluid molecules are taken upby a li
7、quid or solid and distributed throughout the body ofthat liquid or solid.accelerated adsorption testsadsorption tests in which theend point is hastened by testing at conditions more severethan those anticipated in service.acid-extractable materialsubstances dissolved by an acidunder specified condit
8、ions.activated carbona family of carbonaceous substancesmanufactured by processes that develop adsorptive proper-ties.activationany process whereby a substance is treated todevelop adsorptive properties.activityfor activated carbon, the adsorptive capacity of anadsorbent, usually as measured by a st
9、andard test.adsorbateany substance that is adsorbed.adsorbentany solid having the ability to concentrate signifi-cant quantities of other substances on its surface.adsorptiona process in which fluid molecules are concen-trated on a surface by chemical or physical forces, or both.adsorption zonesee m
10、ass transfer zone.ashresidue after the combustion of a substance under speci-fied conditions.as is basisas received.breakpointthe appearance in the effluent of a specifiedconcentration of an adsorbate.breakthrough, nthe first appearance in the effluent of anadsorbate of interest under specified cond
11、itions.channelingthe preferential flow of fluid through passages oflower resistance that can occur in fixed beds or columns ofparticles owing to nonuniform packing, irregular sizes andshapes of the particles, gas pockets, wall effects, and othercauses.chemical adsorption see chemisorption.chemisorpt
12、ion (chemical adsorption)the binding of anadsorbate to the surface of a solid at strengths approximatingthose of a chemical bond.coadsorptionthe adsorption of two or more components onan adsorbent, each affecting the adsorbability of the other.contact batch operationan adsorption process in which an
13、adsorbent is dispersed in a fluid to be treated and thenseparated when practical equilibrium is attained.continuous moving bedan adsorption process characterizedby flow of a fluid through a continuously moving bed ofgranular adsorbent with continuous withdrawal of spentadsorbent and continuous addit
14、ion of reprocessed or virginadsorbent.1This terminology is under the jurisdiction of ASTM Committee D28 onActivated Carbon and is the direct responsibility of Subcommittee D28.03 onNomenclature and Editorial.Current edition approved June 15, 2011. Published August 2011. Originallyapproved in 1967. L
15、ast previous edition approved in 2005 as D2652 05a. DOI:10.1520/D2652-11.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.countercurrent adsorptionan adsorption process in whichthe flow of fluid is in a direction opposite to the movem
16、entof the adsorbent.critical bed depththe minimum depth of an adsorbent bedrequired to contain the mass transfer zone.crushing strengththe property of a particle to resist physicalbreakdown when contained and subjected to a slowlyincreasing continuously applied force.degassingremoval of gases.densit
17、y, absolute or truethe mass under specified condi-tions of a unit volume of a solid sorbent excluding its porevolume and inter-particle voids.density, apparent (density, bulk, packing)the mass underspecified conditions of a unit volume of a solid sorbentincluding its pore volume and inter-particle v
18、oids.density, blocksee density, particle.density, bulksee density, apparent.density, packingsee density, apparent.density, particle (density, block)the mass under specifiedconditions of a unit volume of a solid sorbent including itspore volume but excluding inter-particle voids.density, tampedthe de
19、nsity of packed bed of powderedcarbon.desorptionthe separation of an adsorbate as such from asorbent.differential heat of adsorptionthe heat evolved during theadsorption of an incremental quantity of adsorbate at a givenlevel of adsorption.dosagethe quantity of substance applied per unit weight orvo
20、lume of the fluid being treated.dry basisexclusive of any moisture which may be present.dustan imprecise term referring to particulates capable oftemporary suspension in air or other gases; also, particlessmaller than an arbitrarily selected size.dynamic adsorptive capacitythe quantity of a given co
21、m-ponent adsorbed per unit of adsorbent from a fluid, or fluidmixture moving through a fixed bed at the breakpoint for thatcomponent.effective sizethe particle size, in SI units, which correspondsto 10 percent finer on the cumulative particle size distribu-tion curve.end pointthe occurrence in the e
22、ffluent of the maximumpermissible concentration of an adsorbate of interest.equilibrium adsorptive capacitythe quantity of a givencomponent adsorbed per unit of adsorbent from a fluid orfluid mixture at equilibrium temperature and concentration,or pressure.expanded beda bed of granular particles thr
23、ough which afluid flows upward at a rate sufficient to slightly elevate andseparate the particles without changing their relative posi-tions.fine mesh activated carbonactivated carbon in particlesizes predominantly between 80 mesh and 325 mesh.fines, nparticles smaller than the smallest nominal spec
24、ifiedparticle size.fixed beda stationary bed of granular particles.floatersthe material floating on the surface of water intowhich carbon has been added and has been thoroughlywetted.fluidized beda bed of particles in which the fluid flowsupward at a rate sufficient to suspend the particles com-plet
25、ely and randomly in the fluid phase.Freundlich adsorption isotherma logarithmic plot of quan-tity of component adsorbed per unit of adsorbent versusconcentration of that component at equilibrium and atconstant temperature, which approximates the straight linepostulated by the Freundlich adsorption e
26、quationX/M 5 kCnwhere:X = quantity adsorbed,M = quantity of adsorbent,C = concentration,k and n = constants.granular activated carbonactivated carbon in particle sizespredominantly greater than 80 mesh.hardnessa generic term referring to the resistance of aparticle to breakdown as measured by specif
27、ic tests.heat of adsorptionthe heat evolved during adsorption.hysteresis loopthe divergence between the paths of theadsorption and desorption isotherms.ignition temperature (kindling point) the lowest tempera-ture at which combustion will occur spontaneously underspecified conditions.impact strength
28、the property of a particle to resist physicalbreakdown when subjected to a rapidly increasing appliedforce.integral heat of adsorptionthe sum of the differential heatsof adsorption from zero to a given level of adsorption.intermittent moving bed (pulse, slug) an adsorption pro-cess characterized by
29、upward flow of a fluid through a fixedbed of granular adsorbent with periodic withdrawal of spentadsorbent from the bottom of the bed and additions ofreprocessed or virgin adsorbent to the top of the bed.irreversible adsorptionadsorption in which the desorptionisotherm is displaced toward higher equ
30、ilibrium adsorptioncapacities from the adsorption isotherm.isobara plot of quantity adsorbed per unit of adsorbentagainst equilibrium temperature when concentration or pres-sure is held constant.isoterea plot of equilibrium concentration or pressureagainst temperature when the quantity adsorbed per
31、unit ofadsorbent is held constant.isotherma plot of quantity adsorbed per unit of adsorbentagainst equilibrium concentration, or pressure, when tem-perature is held constant.Langmuir adsorption theorythe theory that assumes thatthe surface of an adsorbent has only uniform energy sites andthat adsorp
32、tion is limited to a monomolecular layer.D2652 112Langmuir isotherma plot of isothermal adsorption datawhich to a reasonable degree fits the Langmuir adsorptionequation.macroporea pore with widths exceeding 50 nanometres(500 angstrom units).mass transfer zone (adsorption zone)the region in whichthe
33、concentration of the adsorbate of interest in the fluiddecreases from influent concentration to the lowest detect-able concentration.mean particle diameterthe weighted average particle size,in SI units, of a granular adsorbent computed by a standardprocedure.mesoporea pore of width between 2 and 50
34、nanometres (20and 500 angstrom units).microporea pore with width not exceeding 2 nanometres(20 angstrom units).moisture contentthe water content of a substance as mea-sured under specified conditions.monomolecular layeran adsorbed film, one molecule thick.multimolecular layeran adsorbed film more th
35、an one mol-ecule thick.oven drying lossthe reduction in weight resulting when asubstance is heated in an oven under specified conditions.pelleted activated carbona form of granular activatedcarbon consisting of cylindrical particles.physical adsorption (van der Waals adsorption)the bind-ing of an ad
36、sorbate to the surface of a solid at energiesapproximating those of condensation.pore diameterthe diameter of a pore in a model in which thepores in a sorbent are assumed to be cylindrical in shape andwhich is calculated from data obtained by a specifiedprocedure.poresthe complex network of channels
37、 in the interior of aparticle of a sorbent.pore volumevolume of the pores in a unit weight of asorbent.pore volume distributionthe distribution of pore volumesamong pores of different sizes or diameters.powdered activated carbonactivated carbon with a meanparticle diameter less than 45 m.preferentia
38、l adsorptionadsorption in which one or morecomponents are adsorbed to a much greater extent thanothers.reactivation (revivification)oxidation processes for restor-ing the adsorptive properties of a spent sorbent.regenerationdistillation or elution-type processes for restor-ing the adsorptive propert
39、ies of a spent sorbent.relative efficiencythe rating of the adsorptive capacity of anadsorbent based on a comparison of its performance withthat of a reference adsorbent in a defined test.retentivitythe ability of an adsorbent to resist desorption ofan adsorbate.reversible adsorptionadsorption in wh
40、ich the desorptionisotherm approximates the adsorption isotherm.revivificationsee reactivation.service life (service time)the elapsed time until the endpoint is reached in an adsorption process.service timesee service life.sorptiona process in which molecules of a fluid are taken upby absorption or
41、adsorption, or both.split feeda liquid-phase adsorption process in which apowdered adsorbent is added to the solution to be treated intwo or more steps, with or without intermediate separation ofthe adsorbent.surface area (B.E.T.)the total surface area of a solidcalculated by the B.E.T. (Brunauer, E
42、mmett, Teller) equa-tion, from nitrogen adsorption or desorption data obtainedunder specified conditions.surface area distributionthe distribution of surface areaaccording to some parameter such as pores of different sizeor diameter.tamped densitysee density, tamped.threshold concentrationthe minimu
43、m concentration atwhich a substance can be detected or recognized by its tasteor odor.uniformity coefficientthe ratio of the particle diametercorresponding to 60 % finer on the cumulative particle sizedistribution curve to the particle diameter corresponding to10 % finer on the same distribution cur
44、ve.van der Waals adsorption see physical adsorption.water-extractable materialsubstances dissolved from othersubstances by water under specified conditions.wettabilitythe rate at which particles can be made wet underspecified conditions.4. Keywordsactivated carbonASTM International takes no position
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