Synthesis of a first generation (G1) PPI dendrimer functionalized with 4-hydroxycoumarin effective for the removal of chromium (III) and chromium (VI) by adsorption

Abstract

The preparation of a first generation (G1) PPI dendrimer functionalized by 4-hydroxycoumarin based on the Manich reaction and its use for chromium removal. The literature review showed that dendrimers are large tree molecules constructed by iterative processes from a molecule with at least three reactive sites. These hyper-branched and multi-functional macromolecules have a perfectly defined structure whose applications in various fields such as catalysis, materials, or biology, or even medicine are constantly developing. Indeed, these dendrimers allow the development of new organic/inorganic materials with a controlled structure, but also to modify, at the nanoscale, the surface of existing materials. Coumarins form a set of molecules with multiple beneficial properties including antioxidant, anti-inflammatory, anticancer, antibacterial, antiviral properties. These molecules have also been shown to be good metal ion chelators and are able to modulate MMPs activity. The study of the adsorption of trivalent chromium and hexavalent chromium by the PPI dendrimer functionalized with Coumarin noted C3, shows that the kinetics are carried out in two stages with a high removal yield for Cr (VI) (56.15%) and very low for Cr (III) (12.98%). In this study, an amount of 30mg of adsorbent is used keeping the initial chromium concentration (30mg/L), pH (2), stirring rate, contact time and temperature constant.