material-science-2019-accepted-abstracts

Page 55

allied

academies

Journal of Materials Science and Nanotechnology | Volume 3

February 25-26, 2019 | Paris, France

Materials Science and Engineering

International Conference on

An integrated application of natural geomaterials for heavy metals removal in aqueous system

Ali SDIRI

University of Sfax, Tunisia

he present work has been conducted to evaluate the

potential application of natural geomaterials, from Tunisia,

in removing toxic metals from aqueous solutions in mono- and

multiple-elements systems. Adsorption experiments were

performed using batch sorptionmethodology as an appropriate

technique in the current study. The chemical and mineralogical

characterizations showed that limestone samples from

southern Tunisia contained up to 99.6% calcium carbonate with

small amounts of clay minerals, including smectite, kaolinite

and illite. The characterization of the collected samples

allowed the selection of the most auspicious sites that could

be excavated for use as adsorbent. We examined the effects

of impurities in limestone on its capacity to retain several

selected heavy metals. The experimental data showed highly

efficient materials in the removal of heavy metals (Pb, Cd, Cu

and Zn). Kinetic data demonstrated a high degree of fitness to

the pseudo-second order and intra-particle diffusion models.

The selectivity sequence of the studied metal was Pb(II) > Cu(II)

> Zn(II) ≈ Cd(II) in single and mixed systems. The applicability

of Tunisian natural clays, from Gabes and Gafsa areas, in the

removal of several metal ions was also evaluated. Mineralogical

and spectroscopic characterizations indicated that the clay

of Gabes area was mainly montmorillonite whereas the

sample collected from Gafsa district contained high amount

of carbonates. From the adsorption studies, it was concluded

that both smectitic and calcareous clays could be used for

the removal of several metal cations in aqueous systems.

The sequence of heavy metals adsorption in single and multi-

element systems onto the studied clays was: Pb(II) > Cu(II) >

Zn(II) > Cd(II). In the mixed systems, the adsorption capacity

decreased for each metal due to the competitive effect. Such

findings are contingent upon some physical properties of the

studied metals (i.e., relative binding strength, hydrated radius,

electronegativity and hydrolysis constant).