What is it about?

The Iraqi bentonite adsorption efficiency for Pb(II) from aqueous solutions was investigated using batch laboratory experiments. The adsorption affecting factors (pH, contact time, adsorbent dosage, ion concentration, and temperature) were empirically studied. The adsorption isotherms were described using Langmuir, Freundlich models. The adsorption efficiency of the Iraqi bentonite for Pb(II) ions decreased with the rise of temperature at 50 mg/ L. The maximum adsorption capacity at 25 C was 0.6563 mg/g, but dropped to 0.5250 mg/g at 35 C. Variation in Gibbs free energy, enthalpy, entropy beside the adsorption energy was studied. The thermodynamic results explored that Iraqi bentonite is of high capacity for the adsorption lead ions, randomness, and exothermic reactions. So it was regarded as a good natural adsorbent can be reduced, specifically Pb(II) ions from the polluted sites.

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Why is it important?

This work deals with the use of the Iraqi natural bentonite to purify the aqueous solutions by reducing or removing Pb(II). It is an empirical investigation for the bentonite adsorption capacity with the optimizing parameters (pH of the solution, adsorbent mass dose, initial ion concentration, contact time, and temperature).


The findings of the current study sort that the Iraqi bentonite capacity as a natural adsorbent material was investigated for removing of lead ions from aqueous solution. The parameters (pH of a solution, adsorbent mass dose, initial concentration, contact time, and temperature) were systematically demonstrated as effective parameters on the adsorption capacity efficiency. The adsorption capacity of bentonite was computed as 0.6063 mg/g at optimizing experimental conditions of pH 6, contact time of 50 min, and temperature of 30 C. Thermodynamically, the free energy, enthalpy and entropy pointed out the exothermic and randomness nature of the adsorption of lead ions on bentonite, and the suitable efficiency of multilayer of bentonite in adsorption of lead ion. Langmuir isotherm equation has the best accordance and has high adsorption energy. Finally, Iraqi natural bentonite is recommended as a natural adsorbent can be used in environmental studies related to the purification of aqueous solutions, particularly, reducing of Pb(II) concentrations from the liquid wastes.

Fatma H Abdulla
University of Baghdad

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This page is a summary of: Purification of aqueous solutions from Pb(II) by natural bentonite: an empirical study on chemical adsorption, Environmental Earth Sciences, May 2017, Springer Science + Business Media, DOI: 10.1007/s12665-017-6725-3.
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