where, KL (litre per microgram) is the Langmuir sorption
equilibrium constant, Q (micrograms per gram) is the maximum
capacity of the sorbent, qs (micrograms per gram) corresponds to
the monolayer saturation capacity, i.e. maximum of sorption of the
1st layer, KB is a constant of sorption and Cs (micrograms per litre)
is the saturation concentration, i.e. the concentration at when all
layers are
filled.