The adsorption process as a function of RL may be
described following Chakravarty et al. (2009): if RL[1
unfavorable, RL = 1 Linear condition, 0RL1 favorable
condition, and RL = 0 irreversible condition. RL lies
between 0 and 1 which is 0.325 and which indicates the
favorable adsorption of Pb(II) ions.