where Ce and Ct are the liquid-phase concentrations of oil in mg/l at
equilibrium and time t, respectively. k1 and k2 are the first order
and second order rate constants, respectively. The pseudo first
order plot of Log(Ce Ct) against t should give a linear relationship
from which k1 in (min1
) can be calculated from the slope of the
graph. A plot of t/Ct will give a rate constant k2 (mg g1min1
) for
pseudo-second order kinetics. Table 4 presents the constant values
and correlation coefficients R2 of both pseudo-first order and
pseudo-second order kinetic models for adsorption of diesel fuel
and vegetable oil by human hair. The kinetic plots showed a good
fit of sorption equilibrium data with respect to pseudo-second
order. This suggests that the rate limiting steps may be
chemisorption involving valence forces [45].