Swift Removal of the Heavy Metals Cadmium and Lead from an Aqueous Solution by a CAN-Zeolite Synthesized from Natural Clay

Lobna Aloui; Soumaya Mezghich; Lamjed Mansour; Sana Hraiech; Fadhila Ayari

doi:10.3390/chemengineering7060113

ChemEngineering (Nov 2023)

Swift Removal of the Heavy Metals Cadmium and Lead from an Aqueous Solution by a CAN-Zeolite Synthesized from Natural Clay

Lobna Aloui,
Soumaya Mezghich,
Lamjed Mansour,
Sana Hraiech,
Fadhila Ayari

Affiliations

Lobna Aloui: Faculty of Sciences of Bizerte, LR 05/ES09 Laboratory of Applications of Chemistry to Resources and Natural Substances and to the Environment (LACReSNE), Carthage University, Zarzouna 7021, Tunisia
Soumaya Mezghich: Institute of Chemistry of Clermont-Ferrand (ICCF), Clermont Auvergne University, CNRS, BP 10448, F-63000 Clermont-Ferrand, France
Lamjed Mansour: Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
Sana Hraiech: Physical Chemistry Laboratory of Mineral Materials and Their Applications, National Center of Research in Materials Sciences, B.P. 73, Soliman 8027, Tunisia
Fadhila Ayari: Faculty of Sciences of Bizerte, LR 05/ES09 Laboratory of Applications of Chemistry to Resources and Natural Substances and to the Environment (LACReSNE), Carthage University, Zarzouna 7021, Tunisia

DOI: https://doi.org/10.3390/chemengineering7060113
Journal volume & issue: Vol. 7, no. 6
p. 113

Abstract

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CAN-zeolite was synthesized with a high purity from natural kaolinite via alkali fusion by hydrothermal treatment at a pressure of 1 kbar H2O. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy and nitrogen adsorption at 77 K. The results show that after AK hydrothermal treatment (under specific conditions), the SBET increases from 5.8 m2g−1 to 30.07 m2g−1 which is six times greater. The AK which was a non-porous or macroporous solid (the nitrogen adsorption/desorption of AK is of type II) became mesoporous (N2 adsorption–desorption isotherms exhibit typical hysteresis of type IV) with a pore size of 5.9 Å. XRD of AK shows the presence of quartz (Q) as impurities, and illite and kaolinite as major fractions; after hydrothermal treatment, the XRD diffractogram shows only fine pics related to CAN-zeolite (with a good crystallinity), confirming the success of the synthesized process. These results suggest that the synthesized CAN-zeolite has the potential to be tested in the removal of heavy metals from waste water as part of a remediation process. Batch reactors were used to evaluate the adsorption isotherms and kinetic studies of heavy metals, cadmium, and lead, by natural kaolinite clay (AK) and synthesized cancrinite zeolite (CAN-zeolite). The results show that the adsorption kinetics of the bivalent heavy metals cadmium and lead are extremely fast with either AK or CAN-zeolite. Equilibrium was reached within 2 min. Adsorption isotherms show that the synthesized CAN-zeolite has a higher adsorption capacity; the retention capacity of lead and cadmium was three times greater than that presented by the natural clay mineral. According to the findings, CAN-zeolite has a higher affinity for PbII (192 mg/g) compared to CdII (68 mg/g). The negative reactive surface sites interacting with these cationic heavy metals resulted in a higher amount of heavy metals adsorption than the cation exchange capacity (CEC). The adsorption information was analyzed using the Langmuir and Freundlich equations. The Langmuir model provided a good fit to the equilibrium data, indicating a monolayer adsorption mechanism.

Published in ChemEngineering

ISSN: 2305-7084 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry
Website: http://www.mdpi.com/journal/ChemEngineering

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