Insights into Starch Coated Nanozero Valent Iron-Graphene Composite for Cr(VI) Removal from Aqueous Medium

Table 2

Saturation capacities, Langmuir, Freundlich, Temkin and Dubinin–Radushkevish isotherm parameters and correlation coefficients () for Cr(VI) adsorption onto NZVI-Gn composite at pH 3.

Model	Nonlinear equation	Description	Isotherm parameters	Value
Langmuir		(mg g^−1): amount of adsorbate adsorbed per unit weight of adsorbent; (mg g^−1): maximum adsorption capacity; KL (L mg^−1): Langmuir affinity parameter; Ce (mg L^−1): equilibrium adsorbate aqueous phase concentration	(mg g^−1); (L g^−1)	143.28; 0.021	0.962
Freundlich		KF ((mg g^−1)/(mg L^−1)^n): Freundlich affinity-capacity parameter; n: Freundlich exponent	((mg g^−1)/(mg L^−1)^n); n	7.01; 1.66	0.949
Temkin		R: universal gas constant (8.314 J K^−1 mol^−1); T: absolute temperature (K); b: heat of adsorption (J); A: binding constant (L mg^−1)	(L mg^−1)	0.21; 81.29	0.948
Dubinin-Radushkevish		: monolayer adsorption capacity (mg g^−1); : mean free energy of sorption (mol^2 Kj^−1)	(mg g^−1); (mol^2 Kj^−1)	73.46; 0.00	0.789