Transesterification of soybean oil catalyzed by combusted oyster shell, which is waste material from shellfish farms, was examined. Powdered oyster shell combusted at a temperature above 700 degrees C, at which point the calcium carbonate of oyster shell transformed to calcium oxide, acted as a catalyst in the transesterification of soybean oil. On the basis of factorial design, the reaction conditions of catalyst concentration and reaction time were optimized in terms of the fatty acid methyl ester concentration expressed as biodiesel purity. Under the optimized reaction conditions of a catalyst concentration and reaction time of 25wt.%. and 5h, respectively, the biodiesel yield, expressed relative to the amount of soybean oil poured into the reaction vial, was more than 70% with high biodiesel purity. These results indicate oyster shell waste combusted at high temperature can be reused in biodiesel production as a catalyst.

Carbon nanotubes (CNTs) are materials of interest in many fields of science and technology because of their remarkable electronic, mechanical, and thermal properties.[1] Soluble CNTs [2] and CNT-polymer nanocomposites, including CNT-DNA (RNA), possess unique superstructures. [3] It is known that patterned carbon nanotubes are formed on prepatterned substrates or prepatterned catalysts during the synthesis of carbon nanotubes. [4] Jiang and co-workers [5] reported the selfassembly formation of large-scale micropatterns on aligned multiwalled carbon nanotubes by the aid of the capillary action of water. Very recently, Li et al. [6] and Zheng and coworkers [7] described polymer-crystallization-driven periodic patterning on CNTs and controlled two-dimensional patterns of spontaneously aligned CNTs from DNA-wrapped CNTs on a SiO 2 surface. We now report the discovery that self-assembly of single-walled CNTs (SWNTs) with a honeycomb structure is spontaneous on solid substrates by simple solution casting of a SWNT-lipid conjugate (complex 1). Since the first report by François and co-workers [8] that selforganized honeycomb structures are formed from star-shaped poly(styrene) or poly(styrene)-poly(paraphenylene) block copolymers in carbon disulfide under flowing moist gas, considerable attention has focused on this area; that is, such superstructures are formed from the solution casting of: i) symmetric diblock copolymers, [9] ii) rod-coil diblock copolymers, [10] iii) a coil-like polymer, [11] iv) ion-complexed polymers, [12] lipid-packaged Pt complexes, [13] v) poly(D,L-lactic-co-glycolic acid), [14] and vi) polysulfone.[15]As shown in Figure 1, complex 1 was easily obtained by the so-called polyion-complexed method; [16] that is, the mixing of an aqueous solution of shortened-SWNTs (s-SWNTs-COO -Na + ) and molecular bilayers of tridodecylmethylammonium chloride (3 C 12 N + Cl -) [17] in water produced a precipitate, which was collected to obtain complex 1. Mioskowski and coworkers [18] used lipids to dissolve CNTs in water; they described the formation of a supramolecular assembly of the lipids-multiwalled CNTs. The Raman spectra of the s-SWNTs and complex 1 were virtually identical (see Fig. S1 in the Supporting Information). The thermogravimetric analysis (TGA) curve (data not shown) of complex 1 revealed that the composition ratio, s-SWNTs/3 C 12 N + , was roughly 1:1 (w/w). Complex 1 was insoluble in water and in organic solvents, such as alcohols, acetone, and ethyl acetate, but soluble in several organic solvents including dichloromethane, chloroform, benzene, and toluene. In Figure 1, photographs of complex 1 and s-SWNTs-COOH only in chloroform are shown (for photographs in other solvent systems, see Fig. S2 in the Supporting Information). It is clear that complex 1 produces a transparent black solution/dispersion in the solvent. The asymmetric and symmetric methylene stretching vibrations in the Fourier transform infrared (FTIR) spectrum of a cast film of complex 1 appeared at 2924 and 2854 cm -1 , respect...

Complex 1, synthesized from anionic shortened single‐walled carbon nanotubes and cationic ammonium lipid dissolved in organic solvents, is cast on pretreated transparent flexible poly(ethylene terephthalate) (PET) films under a higher relative humidity to form thin films with self‐organized honeycomb structures. The cell sizes are controllable by changing the experimental conditions. The lipid, which is the cationic part of complex 1, is easily removed by a simple ion‐exchange method, while maintaining the basic honeycomb structures. After the ion exchange, the nanotube honeycomb films on PET with thinner skeletons exhibit a dramatic decrease in the surface resistivity from insulating to conducting. Carbon nanotubes with honeycomb structures formed by the self‐organization on flexible polymer films are useful in many areas of nanoscience and technology including nanomaterials, nanoelectronics, nanodevices, catalysts, sensors, and so on.

No abstract

No abstract

No abstract

not Available.