Experimental design approach in optimizing the sorption properties of a new generation of reinforced porous hybrid beads

Abstract

A new sorbent called reinforced porous hybrid beads (RPHB) based on an Algerian aluminium pillared montmorillonite (Al-PIMt)/polyvinyl alcohol (PVA) and calcium carbonate (CC) was prepared using the extrusion method. These new composite bead sorbents were characterized by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties for a series of wet RPHB are measured using uniaxial compression tests. These RPHB beads were used in the batch mode sorption of malachite green (MG) in aqueous solution.The effects of independent variables such as the initial concentration of MG, the sorbent dose and the pH of the suspension as well as their interactions during sorption processes areinvestigated. A Box–Behnken design based on the response surface methodology (RSM) is applied to evaluate the main effects of the variables. The response in term of the MG removal efficiency is maximized. The study of the interactions between the three variables shows that the initial concentration of MG and the pH of the aqueous media appear to be the most significant variables which significantly affect the elimination of MG. The optimal values favorable for the best sorption of MG on these new porous beads are an initial concentration of MG (92.36 mg L−1), a pH of the aqueous medium (pH = 5.01) as well as the dose of the RPHB sorbent (1.03 g L−1).Statistical analysis results show a good correlation between the experimental results and those predicted with a very satisfactory coefficient of determination value (R2 = 0.99).