Co	initial concentration of metal ions (mg/dm3)
Ce	concentration of metal ions at equilibrium (mg/dm3)
qe	sorption capacity at equilibrium (mg/g)
qt	sorption capacity at any time (mg/g)
Re	the percentage removal at equilibrium
qmax	maximum sorption capacity (mg/g)
KL	Langmuir constant (L/mg)
KF	Freundlich constant (mg1−(1/n)(dm3)1/ng−1)
n	heterogeneity factor
KT	the equilibrium binding constant corresponding to the maximum binding energy (dm3/g)
B	constant related to the heat of sorption (J/mol)
bt	Temkin isotherm constant
k1	the pseudo-first order rate constant (1/min)
k2	the pseudo-second order rate constant (g/(mg·min))
kid	the intra-particle diffusion rate constant (mg/g·min0.5)
I	intercept of the line in Weber-Morris model
qe exp	experimental amount of metal adsorbed at equilibrium (mg/g)
qe cal	calculated amount of metal adsorbed at equilibrium (mg/g)