Activated carbon surfaces were modified using molten KNO3 to introduce functional groups and form microtextures. Their surface treatment temperatures were 250—300 °C; the melting point of KNO3 is 337 °C. Microtextures formed on the surfaces of the activated carbons during the molten KNO3 treatment. Furthermore, various functional groups such as -COOH, -COO, and -CO, were observed clearly in XPS spectra of the surface-modified activated carbons. Their metal-ion adsorption ability increased in the order of activated carbon modified at 300 °C > activated carbon modified at 250 °C > original activated carbon.
A characteristic micro-flower structure of zinc oxide (ZnO) was obtained using cathodic electrodeposition from a zinc chloride solution containing an organic dye (Eosin Y) and a nonionic surfactant (TritonX-100). Cyclic or linear-sweep voltammetry using a rotating-disc electrode was employed to analyze the micro-flower structure formation process. The dye forms a complex with zinc cation (Zn2+) to control the deposition as oxide, which is accompanied by pH change near the cathode. The surfactant concentration and the disc electrode rotation rate are key factors determining the deposit morphology. In the solution containing optimum surfactant concentration, the rate of oxygen reduction reaction is increased to produce ZnO. The size and the shape of the complex of Zn2+-dye-surfactant influence the micro-flower structure of the deposit. This report presents a schematic model for the micro-flower formation mechanism. Using the model, the ZnO micro-flower size was controlled experimentally according to the surfactant molecular weight.
Precursor solutions were prepared by the reaction of (2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 9-heptadecafluorononyl)oxirane with 3-aminopropyltrimethoxysilane in ethanol, followed by hydrolysis in the presence of acetic acid. The resulting solutions were mixed with another solution prepared using methyltriethoxysilane. Glass substrates were coated using these solutions and subsequent heat treatment. The resultant hybrid films showed a contact angle with water of 104° and pencil hardness of 8 H.
Synthesis of carbon nanofibers at low-temperatures was attempted using a solid phase carbon source: graphite plate. Carbon was supplied from the graphite plate to nickel attached onto the surface of graphite plate by DC sputtering. The 300-nm-long carbon nanofibers were grown by heating the substrate for 30 min at 550 °C using IR irradiation.