Table 3.

Models and formulae for isotherms³².

Model		Parameters
Langmuir $q_e=\frac{q_m{K}_L{P}_{CO2}}{1+K_L{P}_{CO2}}$	$q_m$	qm is the max adsorption value of CO2 (mg g−1)
	$K_1$	Langmuir equilibrium constant (bar−1)
	$q_e$	qe is the value of CO2 adsorption capacity (mg g−1)
	P	P is the equilibrium pressure (bar)
Freundlich $q_e=K_f\times {P_{CO2}}^{\frac{1}{n}}$	$K_F$	KF is the Freundlich model constants [(mg g−1). (bar−1)1/n)]
	$n$	n is Freundlich isotherm constant (dimensionless)
	qe	qe is the value of CO2 adsorption capacity (mg g−1)
D-R $\text{ln}{q}_e=\text{ln}{q}_m-\beta .{\epsilon }^2$ $\epsilon =RTln\left[1,+,\frac{1}{P_{CO2}}\right]$	$q_m$	The single-layer adsorption capacity
	$\beta$	The constant associated with adsorption energy (mol2 KJ−2)
	$q_e$	The amount of CO2 adsorbed per unit mass of AC at equilibrium (mg g−1)
	$\epsilon$	Adsorption potential (kJ mol−1)
	R	gas constant (8.314 J mol−1 K−1)
Hill $q_e=\frac{q_{s_H}{P_{CO2}}^{n_H}}{K_D+{P_{CO2}}^{n_H}}$	$q_s$	qsH is saturation for maximum uptake (mg/L)
	$n$	nH coefficient of binding interaction
	$K_D$	Hill constants
	P	P is the equilibrium pressure (bar)