© A.W.Marczewski 2002
Reload Adsorption Guide
Notation
in preparation
See also: Adsorption Glossary, Basics and References
A B
C D
E F
G H
I J
K L
M N
O P
Q R
S T
U V
W X
Y Z
 A

A
 specific surface area, [m^{2}/g] (see also S), typically A_{BET} or A_{L} (determined by fitting BET or Langmuir isotherm)

a, A, ads, Ads
 (true) adsorbed amount, [mol/g], [mol/m^{2}] ("n" is usually recommended)

a_{m}
 monolayer capacity (see "a")  maximum adsorption in monolayer, [mol/g], [mol/m^{2}]

a_{mic}
 micropore (adsorption) capacity (see "a")  maximum adsorption in micropores, [mol/g], [mol/m^{2}]

a_{o}
 adsorption capacity (see "a")  maximum adsorption  less specific than a_{m} or a_{mic}, [mol/g], [mol/m^{2}]

α
 interaction coefficient in FG (FowlerGuggenheim) isotherm [],
 B

B
 parameter of DR (DubininRadushkevich) and DA (DubininAstakhov) isotherm equations, []
 C

c, C
 molar concentration of solute, [mol/dm^{3}]

c_{s}, C_{s}
 molar concentration at saturation, [mol/dm^{3}]

C
 adsorption equilibrium constant in BET isotherm equation([1/Pa]; may be dimensionless if relative pressure, x, is used)  the same as K

χ(ε)
 differential energy distribution function ([mol/kJ] for energy ε)

χ(E)
 differential energy distribution function ([] for reduced energy E)
 D

Δ_{n}
 ndimensional integration space
 E

ε
 adsorption energy, [kJ/mol]

ε_{ij}
 energy of adsorption of component "i" replacing desorbed component "j", ε_{ij} = ε_{i}  ε_{j} (competitive adsorption) [kJ/mol]

E
 reduced adsorption energy, E = ε/RT , []

E_{ij}
 reduced energy of adsorption of component "i" replacing desorbed component "j", E_{ij} = E_{i}  E_{j} (competitive adsorption) []
 F

ø
 volume fraction (other notation details are the same as for molar fractions, x) []

F(ε)
 integral (cumulative) energy distribution function, dF/dε ([mol/kJ] for energy ε)

F(E)
 integral (cumulative) energy distribution function, dF/dE ([] for reduced energy E)
 G
 H
 I
 J
 K

K
 adsorption equilibrium constant, K = K_{o}exp(ε/RT) (gas: [1/Pa], solute: [dm^{3}/mol]; may be dimensionless if relative pressure or concentration, x, is used)

K_{i}
 adsorption equilibrium constant for ith component

K_{ij}
 adsorption equilibrium constant for the competition of components "i" and "j",
K_{ij} = K_{i}/K_{j}
K_{ij} = K_{o,ij} exp(ε_{ij}/RT) = K_{o,i}/K_{o,j} exp[(ε_{i}  ε_{j})/RT]

K_{o}
 preexponential (entropic) factor (gas: [1/Pa], solute: [dm^{3}/mol]; may be dimensionless if relative pressure or concentration, x, is used)

K_{n}
 association constant in Kiselev isotherm, []
 L
 M

m
 heterogeneity parameter (F, GF, LF, Tóth, GL ... isotherm equations; 0 < m ≤ 1 ) []
 N

n
 heterogeneity parameter (LF, GL isotherm equations; 0 < m ≤ 1 ) []

n
 parameter of DA (DubininAstakhov) isotherm (DR: n=2, F: n=1; typical DA: 3 or 4) []

n
 no. of mixture components []

_{i(n)}
_{i(n)} (in index)
 for ith component in ncomponent mixture

_{n} (in index)
 ncomponent vector

n
n_{i}
 amount [mol] of species/component "i"

n^{e}
n^{e}_{i}
 excess adsorption, excess adsorbed amount, [mol/g], [mol/m^{2}]; index "i"  component "i"
 O
 P

p, P
 gas/vapor pressure, [Pa], [mmHg]

p_{s}, P_{s}
 vapor pressure at saturation, [Pa], [mmHg]
 Q
 R

R
 Universal gas constant, 8.314 [J/mol K]
 S

S
 specific surface area, [m^{2}/g] (see also A), typically S_{BET} or S_{L} (determined by fitting BET or Langmuir isotherm)

σ
 crosssection area (e.g. 0.162 nm^{2} for N_{2})

σ_{E}
 dispersion of reduced adsorption energy []
 T

T
 Absolute temperature [K]

θ
 relative adsorption, adsorption coverage
θ = adsorption / monolayer capacity
θ = adsorption / adsorption capacity (also for micropores)
 U
 V

v
 gas volume

V
 adsorbed amount expressed as volume of gas/vapor adsorbate at STP (1013.25hPa, 273K) per adsorbent mass, [cm^{3}/g STP]

V_{m}
 monolayer capacity (determined by fitting the BET eq.) expressed as volume of gas/vapor adsorbate at STP (1013.25hPa, 273K) per adsorbent mass, [cm^{3}/g STP]

V_{mic}
 micropore capacity (determined by tplot or α_{s} method) expressed as volume of liquid adsorbate per adsorbent mass, [cm^{3}/g]

V_{meso}
 mesopore capacity (determined by e.g. BJH method) [cm^{3}/g]

V_{0.98}
 total pore capacity determined at relative pressure x = 0.98 [cm^{3}/g]
 X

x
 molar fraction, []

x^{s}_{i(n)}
x^{l}_{i(n)}
 molar fraction of component "i" in ncomponent mixture in surface ("s") or bulk ("l") phase, []

x^{s}_{i(n)l}
x^{s}_{i(n)t}
 molar fraction of component "i" in ncomponent mixture in surface ("s") phase  for local patch/particular site type (subscript "l") or total  averaged for entire surface phase (subscript "t"), []

x
 relative vapor pressure, x = p/p_{s}, []
relative solute concentration, x = c/c_{s}, []
 Y
 Z

z(F)
 relative reduced adsorption energy, z(F) = E(F)  E_{o} (E_{o}  characteristic reduced energy, e.g. average or minimum reduced energy E);
z(F) is inverse function to the integral (cumulative) energy distribution F(z) = F(EE_{o})
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