Nanofibrous and nanotubular supports for the immobilization of metalloporphyrins as oxidation catalysts

Clay Mineral Nanotubes: Stability, Structure and Properties

“…For instance, halloysite is a viable nanocage for inclusion of biologically active molecules with specific sizes due to the empty space inside the NT Price et al, 2001). It has been used as support for immobilization of catalysts such as metallocomplexes (Nakagaki & Wypych, 2007;Machado et al, 2008) and for the controlled release of anti-corrosion agents, herbicides, fungicides Shchukin et al, 2006;Shchukin & Mohwald, 2007). It exhibits interesting features and offers potential application as entrapment of hydrophilic and lipophilic active agents, as enzymatic nanoscale reactor (Shchukin et al, 2005); as sustained release of drugs (Price et al, 2001;Levis & Deasy, 2003;Kelly et al, 2004;Veerabadran et al, 2007); as adsorbing agent for dye removal (Liu et al, 2011).…”

“…Chrysotile (Piperno et al, 2007;Anbalagan et al, 2010) can be synthesized in aqueous solution under mild conditions, easily modified (Wypych et al, 2004;Wang et al, 2006;Wang et al, 2009) and functionalized (Nakagaki & Wypych, 2007). Therefore chrysotile is an interesting target material to be used as component of hybrid materials, support for catalysis, ionic channels, molecular sieving, for gas storage Nakagaki & Wypych, 2007) and other applications in nanotechnology. Stoichiometric chrysotile has been synthesized and characterized by structural and spectroscopy analyses (Falini et al, 2002;Falini et al, 2004).…”

“…In spite of the polydispersity of the chrysotile NTs and the environmental concern of asbestos, many attempts for modifying and functionalizing chrysotile NTs have been reported. Chrysotile has been studied in many fields such as support for immobilization of metalloporphyrins, oxidation catalysts, fixation of CO 2 by chrysotile under low-pressure (Larachi et al, 2010), modification of chrysotile surface by organosilanes, functionalization of single layers and nanofibers to produce polymer nanocomposites (Wang et al, 2006;Nakagaki & Wypych, 2007;Wang et al, 2009) and to produce selfassembled systems (De Luca et al, 2009). Furthermore, many studies have reported the partial or total substitutions of magnesium atoms at chrysotile sites for different atoms as Fe and Ni (Bloise et al, 2010).…”

“…Imogolite is the most representative species of this case, since it has been studied in a pre-nano (1970) decade (Cradwick et al, 1972) and has been nearly forgotten until recently. Since 2000 (Bursill et al, 2000;Tamura & Kawamura, 2002;Mukherjee et al, 2005;Nakagaki & Wypych, 2007), these structures gained again prominence in the literature and appear as an emerging field of research. They can be used as nanoreactors for selective catalysts, adsorbent, nanocable, support for the immobilization of metalloporphyrins, encapsulation and ionic conductor (Nakagaki & Wypych, 2007;Kuc & Heine, 2009).…”

“…However, recently, those clays again became the focus of research and patents Redlinger & Corkery, 2007) due to the great interest in the nanometric structures. Nanostructures (nanotubes and nanospirals) of clay minerals are very versatile systems, and are target materials for applications in catalysis (Imamura et al, 1996), molecular sieves and adsorbents (Ackerman et al, 1993), inorganic support for catalysts (Nakagaki & Wypych, 2007), controlled drug release (Veerabadran et al, 2007), formation of composites, controlled release devices of herbicides, fungicides and insecticides (Lvov et al, 2008) and anti-corrosion agents.…”