Sorption isotherm models for MO uptake by An/CNT composite.

Isotherm Model	Linear form	Parameters	Ref.
Langmuir	, RL = 1/(1 + bC0), RL > 1 (unfavorable adsorption), RL = 1 (linear adsorption), 0 < RL < 1 (favorable adsorption), RL = 0 (irreversible adsorption)	C e (mg L−1): equilibrium concentration of the residual MO in the solution	56 and 57
		q e (mg g−1): removed amount of MO at equilibrium
		q max (mg g−1): maximum adsorption capacity
		b (L mg−1): Langmuir constant
		q max = 1/slope
		b = slope/intercept
		C 0: initial MO concentration
		R L: equilibrium parameter of Langmuir equation
Freundlich		C e (mg L−1): equilibrium concentration of the residual MO in the solution	58
		q e (mg g−1): removed amount of MO at equilibrium
		K F (mg g−1): MO adsorption capacity
		n: heterogeneity factor
		k F = 10intercept
		1/n = slope
Temkin	qe = B ln A + B ln Ce, B = RT/b	A (L g−1): Temkin isotherm constant (the equilibrium binding constant corresponding to the maximum binding energy)	59
		B (J mol−1): Temkin constant related to heat of sorption
		b: Temkin isotherm constant
		R: the gas constant (8.314 J mol−1 K−1)
		T: the absolute temperature at 298 K
		A = EXP(intercept/slope)
		b = slope