In situ polymerization of 4-vinylpyridine/bentonite composites and their application for toluene removal

A new composite material, able to remove organic molecules from aqueous solutions, is obtained by in situ polymerization of 4-vinylpyridine (4VP) in bleaching clay (BC, bentonite) as support. The 4VP monomer is inserted into the interlayer space of the BC using N-dodecylpyridinium chloride (DPC) as tensioactive intercalating reagent. Thus, three composite samples (BCP-1, BCP-2, and BCP-3) were prepared by varying the initial amount of DPC. Thermogravimetric analysis reveals good stability of the new materials at high temperatures. Fourier-transform infrared (FTIR) analysis clearly shows that 4VP is effectively polymerized and adsorbed onto bentonite. Good efficiency in removing toluene from aqueous solution is demonstrated by adsorption kinetics. Batch adsorption studies are conducted to evaluate the effects of the initial DPC amount. We show in this work that an increase of the amount of DPC increases the introduction of 4VP monomer onto the bentonite. Consequently, the amount of coated poly(4-vinylpyridine) P4VP rises. Organic modification leads to an increase in the amount of toluene adsorbed. The obtained results clearly show that the composite samples BCP-X (X = 1, 2, 3) are efficient in toluene removal from aqueous solution, showing thus the hydrophobic character of these materials.