CMC		carboxymethyl chitosan
PAMAM		poly(amidoamine)
Nomenclature
C	the constant proportional to the extent of the boundary layer thickness (mg·g−1)
C 0	the initial concentrations of the metal ion (mg∙L−1)
C e	the equilibrium concentrations of the metal ion (mg∙L−1),
E DR	the mean free energy of adsorption
k 1	the rate constants of pseudo-first-order model (min−1),
k 2	the rate constants of pseudo-second-order model (g∙mg−1∙min−1)
k int	the rate constants of intraparticle diffusion kinetics model (mg·g−1·min−0.5)
K d	the distribution coefficient (mL∙g−1)
$K_{\mathrm{d}}^{\mathrm{U}\left(\mathrm{VI}\right)}$	the distribution coefficients of uranyl ion
$K_{\mathrm{d}}^{\mathrm{M}\left(\mathrm{x}\right)}$	the distribution coefficients of other ions
K F	Freundlich constants, indicating adsorption intensity
K L	the Langmuir adsorption equilibrium constant (L·mg−1)
m	the amount of the sorbent (g)
n	Freundlich constants, indicating adsorption capacity
q e	the amount of adsorption at equilibrium (mg∙g−1)
q e(U)	the adsorption capacity of uranium (mg·g−1)
q e(Total)	the total amount of adsorption for all multi-ions (mg∙g−1).
q DR	the theoretical adsorption capacity (mol·g−1)
q m	the maximum or saturated amount of adsorption (mg∙g−1)
q t	U(VI) adsorption capacity at t (mg·g−1)
R	the ideal gas constant (8.314 kJ·mol−1 K−1)
R L	the dimensionless constant separation factor
S U	degree of selectivity of the adsorbent towards uranium
S U(VI)/M(x)	the selectivity coefficient of uranyl ions relative to competing ions
S r	the relative selectivity coefficient
t	the adsorption time (min)
T	the absolute temperature (K).
V	the volume of the solution (L)
Greek letters
β	the constant associated with the adsorption energy (mol2·kJ−2)
ε	the Polanyi potential
ΔS°	standard entropy (J·mol−1·K−1)
ΔH°	standard enthalpy (kJ·mol−1)
ΔG°	standard Gibbs free energy (kJ·mol−1)