Abstract: This work was to study batch biosorption of Pb(II)
ions from aqueous solution by Luffa charcoal. The effect of operating
parameters such as adsorption contact time, initial pH solution and
different initial Pb(II) concentration on the sorption of Pb(II) were
investigated. The results showed that the adsorption of Pb(II) ions
was initially rapid and the equilibrium time was 10 h. Adsorption
kinetics of Pb(II) ions onto Luffa charcoal could be best described by
the pseudo-second order model. At pH 5.0 was favorable for the
adsorption and removal of Pb(II) ions. Freundlich adsorption
isotherm model was better fitted for the adsorption of Pb(II) ions than
Langmuir and Timkin isotherms, respectively. The highest monolayer
adsorption capacity obtained from Langmuir isotherm model was
51.02 mg/g. This study demonstrated that Luffa charcoal could be
used for the removal of Pb(II) ions in water treatment.
Abstract: The equilibrium, thermodynamics and kinetics of the
biosorption of Cd (II) and Pb(II) by a Spore Forming Bacillus (MGL
75) were investigated at different experimental conditions. The
Langmuir and Freundlich, and Dubinin-Radushkevich (D-R)
equilibrium adsorption models were applied to describe the
biosorption of the metal ions by MGL 75 biomass. The Langmuir
model fitted the equilibrium data better than the other models.
Maximum adsorption capacities q max for lead (II) and cadmium (II)
were found equal to 158.73mg/g and 91.74 mg/g by Langmuir model.
The values of the mean free energy determined with the D-R equation
showed that adsorption process is a physiosorption process. The
thermodynamic parameters Gibbs free energy (ΔG°), enthalpy (ΔH°),
and entropy (ΔS°) changes were also calculated, and the values
indicated that the biosorption process was exothermic and
spontaneous. Experiment data were also used to study biosorption
kinetics using pseudo-first-order and pseudo-second-order kinetic
models. Kinetic parameters, rate constants, equilibrium sorption
capacities and related correlation coefficients were calculated and
discussed. The results showed that the biosorption processes of both
metal ions followed well pseudo-second-order kinetics.