THE REMOVAL OF PENTACHLOROPHENOL ON GELIFIED BEADS OF IRON PILLARED MONTMORILLONITE-SODIUM ALGINATE

Abstract

The objective of this paper is to prepare an innovative bioadsorbents in the form of capsules or gelified beads based on a mixture of pillared clay and a polysaccharide-type copolymer: sodium alginate (SA). Firstly, iron-pillared clays (montm-Fex(OH)y) were prepared by co-adsorption of a surfactant molecule CTAB (montm-Fex-(OH)y-CTAB) using well-defined operating conditions. In the second part, we encapsulated the prepared supports using the copolymer sodium alginate. In the encapsulation of the prepared supports, we optimized the following parameters: diameter of spherical beads, pillared clay/sodium alginate ratio (PC/AS). These prepared spherical beads were characterized by various methods before their use. The aim is to determine the swelling rate (S), apparent (d_app) and real (d_r) densities, porosity (ε), total pore volume (T.P.V), the SEM was employed to examine the morphology of the studied supports and FTIR spectroscopy to locate different characteristic absorption bands of each product. For the application part, we focused on the adsorption of a model molecule: pentachlorophenol (PCP). The kinetic study was carried out from the contact time (adsorbent-adsorbate) to duration of 30 hours by varying the following parameters (particle size, PC/SA ratio) to determine the equilibrium time. The results obtained showed that a contact time of 5 to 7 hours is sufficient for maximum retention of PCP. The best class of absorbent capsules are those with a size equal to 2.5 mm and r (PC/SA) equal to 2 for residual concentrations lower than 10 µmole/l. The modeling of sorption isotherms showed that the two models of Freundlich and Langmuir are fully applicable.