The Freundlich isotherm describes adsorption on heterogeneous surfaces and assumes that stronger binding
sites are occupied first (Freundlich, 1907). The model is empirical and is expressed by the equation:
$$Q = K_f \cdot C_e^{1/n}$$
where \(Q\) is the amount adsorbed, \(C_e\) is the equilibrium concentration,
\(K_f\) is the Freundlich constant related to adsorption capacity, and \(n\) is the heterogeneity factor
(indicating adsorption intensity).
For more information, see Freundlich (1907): tools:::Rd_expr_doi("https://doi.org/10.1002/ange.19070201805")