ABSTRACT
This chapter describes the ability of clays and surface-modified clays in promoting advanced oxidation processes such as wet air/peroxide oxidation usually in conjunction with Fenton and photo-Fenton reactions. The oxidative and photolytic degradation reactions of phenol, substituted phenols, organic dyes, and contaminants, in the presence of iron-rich, Fe3+-exchanged layer silicates together with metal oxide-impregnated and pillared interlayered clays, are summarized in a series of tables. The epoxidation of alkenes has also received much attention. The rate of degradation generally obeys the Langmuir-Hinshelwood equation. Clay-supported metal-organic complexes and metal nanoparticles can similarly promote various reduction, hydrogenation, and deoxygenation reactions. The ability of montmorillonite and other smectites to mediate asymmetric/enantioselective organic reactions and syntheses is related to their capacity for intercalating chiral transition metal chelates as either a single or a double layer of molecules. For example, the smectite-immobilized cationic chiral complexes of Cu(II) with bis(oxazoline) or pyridine-oxazoline ligands can promote the enantioselective cyclopropanation of styrene with ethyl diazoacetate. Similarly, montmorillonite-intercalated dicationic chiral Mn(III) salen complexes can promote the enantioselective oxidation of styrene and indene.
