Adsorption isotherm, kinetic and thermodynamic studies for the removal of Pb(II), Cd(II), Zn(II) and Cu(II) ions from aqueous solutions using Albizia lebbeck pods

Abstract

Powdered adsorbent prepared from Albizia lebbeck pods as agricultural waste has been used for the adsorption of Pb(II), Cd(II), Zn(II) and Cu(II) ions from aqueous solutions. The powdered adsorbent was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller. Effects of various parameters like contact time, solution pH, initial concentration dosage and temperature were investigated on a batch adsorption system. Equilibrium and kinetic experiments were carried out at the optimum pH of 6, 8 and 10 at 29 °C using particle size of 250 μm for Cd(II), Pb(II), Zn(II) and Cu(II) ions. Changes in free energy, enthalpy and entropy were also evaluated. The adsorption data fitted well with the Langmuir isotherm model with correlation coefficient (R 2 > 0.94), whereas the adsorption kinetics followed the pseudo-second-order kinetics. The thermodynamic parameters proved that adsorption of metal ions is endothermic and non-spontaneous at low temperatures, while spontaneity occurred at higher temperatures. This study shows that powdered Albizia lebbeck pods prove to be a promising inexpensive adsorbent for metal ion removal from aqueous solutions.

Characterization and Performance Evaluation of Cellulose Acetate–Polyurethane Film for Lead II Ion Removal

“…Pb 2+ adsorption of CA–PU45 was due to OH, CO, and NH functional groups, which acted as the binding sites [ 43 ]. Previous studies reported the adsorbate–adsorbent interaction through the electrostatic force [ 44 , 45 ]. Some others have reported that the chelation is responsible for the mechanism of Pb uptake, and the N-containing functional groups (such as NH and N-C=O) serve as the ligand [ 12 , 24 ].…”

Efficient Removal of Metals from Synthetic and Real Galvanic Zinc–Containing Effluents by Brewer’s Yeast Saccharomyces cerevisiae

“…Another parameter which allows us to determine the applicability of kinetic model is adsorption rate value. At almost similar R 2 and SSE , the adsorption rate values for pseudo-first order model were lower than for the pseudo-second-order model, indicating a lower rate of adsorption [ 24 ].…”

Removal of Cadmium from Aqueous Solutions by Saccharomyces cerevisiae–Alginate System

“…The biosorption capacities at 5 and 10 mg/L initial Cd 2+ concentration were 4.3 and 9.2 µg of Cd 2+ /g of capsules (at 15 min of aqueous solution contact time), respectively ( Figure 6). The probability of biosorption of Cd 2+ on the active sites of the yeast-alginate system increased as Cd 2+ became more concentrated in the aqueous solution, due to an increase in the driving force that overcame the mass transfer resistance of Cd 2+ between the liquid and solid phases [48]. The biosorption capacities at 5 and 10 mg/L initial Cd 2+ concentration were 4.3 and 9.2 µg of Cd 2+ /g of capsules (at 15 min of aqueous solution contact time), respectively ( Figure 6).…”

“…This percentage was higher than the removal efficiency of encapsulated S. cerevisiae in the batch study (51.9% ± 0.7%) using the same concentration and contact time, and even higher than the Cd 2+ removal efficiency of free S. cerevisiae (75.0% ± 0.1%). A possible explanation for the increase in Cd 2+ efficiency when changing from batch to continuous conditions is the increase in the driving force of Cd 2+ due to the constant flux of solution [48].…”