ABSTRACT
This chapter focuses on surface properties of laponite using pyrene as a photophysical probe molecule have revealed that the adsorption capacity, polarity, and electron-accepting ability of the laponite surface are dependent on the preactivation temperature and on actual conditions that laponite undergoes. It aims to assess the conditions that lead to the photodegradation of molecules adsorbed on clays. Alumina, silica-alumina, and zeolites are also studied as model systems that gradually approach the complexity of a clay system. Zeolites have long been used in catalysis, petroleum refining, water treatment, and ion and molecular sieving. In contrast to the amorphous nature of most adsorbents and solid catalysts, zeolites exhibit unique uniform ionic frameworks with pores and tunnels. Pyrene cation radicals are formed on γ-alumina and silica-alumina surfaces. Spectroscopic study shows that the absorption spectrum of the pyrene cation radicals produced on surfaces fades on contact with water vapor and that pyrene absorption peaks simultaneously increase.
