Cysteine-montmorillonite composites for heavy metal cation complexation: A combined experimental and theoretical study

Abstract

Green Composites based on montmorillonite (Mt) and cysteine, were prepared for heavy metal removal. A comparison between the adsorption properties of the resulting hybrid inorganic-organic materials and the pure montmorillonite was carried out for the following heavy metal cations Cd 2+ , Hg 2+ , Pb 2+ , Co 2+ and Zn 2+. It appears that the adsorption capacity is higher on the composite. Moreover, in release experiments, the heavy metal cations are more strongly retained by the hybrid material. Interactions between the hybrid clay mineral and the inorganic hosts were studied by spectroscopic methods such as solid-state NMR (Nuclear Magnetic Resonance) and FTIR (Fourier Transform Infrared). The experimental data were in agreement with the theoretical periodic DFT (Density Functional Theory) calculations where a molecular picture of the adsorption complex is proposed.

Adsorption and photophysical properties of fluorescent dyes over montmorillonite and saponite modified by surfactant

“…The edges and the faces of clay particles are responsible to adsorb cations, anions, nonionic and polar contaminants from natural water. Adsorption of pollutants over the surface of clay may occur through ion exchange, ion-dipole interaction or coordination process from either strong or weak interactions [11,12].…”

Green biosorbents based on chitosan-montmorillonite beads for anionic dye removal

“…The nanometer thick layers of Mt consist of aluminum octahedron sheet sandwiched between two silicon tetrahedron sheets. Isomorphic substitution of Al 3+ with Mg 2+ in the octahedral sheets gives an overall negative charge, which is counterbalanced by cations (Na + , Ca 2+ , Mg 2+ and Fe n+ ) located in the interlayer space [29][30][31][32]. Clay minerals are abundant in nature and consequently low cost.…”

Thiabendazole/bentonites hybrids as controlled release systems

“…The specific physical and chemical properties of clay minerals such as adsorption, cation exchange capacity, swelling capacity, ability to form colloidal solutions, optimum rheological behavior and dispersibility in water [3][4][5][6] as also their low cost, abundance, biocompatibility versatility and effectiveness, have resulted, in recent decades, in the introduction of these minerals, into various technological processes [7][8][9][10][11][12][13][14][15][16] Clay minerals have therefore now been introduced as components in various pharmacological formulations, in which they are used as excipients. In addition to classic pharmaceutical uses, they can also be employed in the development of new drug delivery systems (DDS) [17][18][19] Although all pharmaceutical dosage forms can be considered to DDS (since they use the administration of drugs intended to reach a site of action and maintain a certain concentration over the entire period of treatment), the final therapeutic effect of a pharmaceutical treatment will depend on several factors, which will involve the nature of the drug as well as the form taken for its administration and dosage [2,18].…”