Transformation of 1-Aminonapththalene at the Surface of Smectite Clays

Abstract

Abstract--One-aminonaphthalene is sorbed onto the Na-saturated smectite clays, montmorillonite and hectorite, by cation exchange. In the presence of Fe 3 § either in the clay structure or on the clay surface, sorption is followed by the formation of a blue-colored complex, with the continuous disappearance of aminonaphthalene from solution and the clay surface. The rate of aminonaphthalene disappearance decreases as pH increases. With time, four major products that appear to be structural isomers of N(4-aminonaphthyl)-1-naphthylamine are produced. A simplified model of this transformation is suggested to be the oxidation by Fe 3 § of sorbed aminonaphthalene forming a radical cation-clay complex. A subsequent reaction between the radical-cation and a neutral aminonaphthalene molecule takes place, with the products being strongly sorbed to the clay surface.

In situ Measurements of Tetraphenylboron Degradation Kinetics on Clay Mineral Surfaces by IR

“…It is possible that changes in structure and surface charge during the course of reaction affect the reaction rate on nontronite. Since the reaction did not proceed on hectorite, which is iron free, it is reasonable to assume that iron can be the electron acceptor in montmorillonite as has been argued previously (25). In this instance, we assume that the reduction is almost entirely of octahedral Fe-O-Al, based on the much lower quantity of iron in SWy-1 relative to NG-1.…”

Decolorization of methylene blue by δ-MnO2-coated montmorillonite complexes: Emphasizing redox reactivity of Mn-oxide coatings

“…The concentration of Mn(II) used in each system was based on corresponding loadings of Mn oxide in the Mn-Mts. We assume MB oxidation by uncoated Na-Mt negligible in time scale of the experiments, though it has been reported that iron-bearing montmorillonite can oxidize phenols and aromatic amines, for instance, in a long duration [39]. The oxidation of Mn(II) ions by O 2 in the uncoated Na-Mt system during the experiments was expected trivial because of slow kinetics in acidic solution.…”

Transport of aminonaphthalene with a site-limited transformation reaction

“…The sorption and transformation of aminonaphthalene has previously been reported as relatively rapid (98% in 24 h) in a batch system with an excess number of sites (3). In situations where the number of transformation sites was not in excess or there was a stoichiometric balance of reactants, the observed rate of approach to equilibrium might be considerably slower.…”