Meisei University

About: Meisei University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Photodegradation & Aqueous solution. The organization has 821 authors who have published 1663 publications receiving 33483 citations. The organization is also known as: Meisei Daigaku.

Ethanol fermentation from biomass resources: current state and prospects.

Abstract: In recent years, growing attention has been devoted to the conversion of biomass into fuel ethanol, considered the cleanest liquid fuel alternative to fossil fuels. Significant advances have been made towards the technology of ethanol fermentation. This review provides practical examples and gives a broad overview of the current status of ethanol fermentation including biomass resources, microorganisms, and technology. Also, the promising prospects of ethanol fermentation are especially introduced. The prospects included are fermentation technology converting xylose to ethanol, cellulase enzyme utilized in the hydrolysis of lignocellulosic materials, immobilization of the microorganism in large systems, simultaneous saccharification and fermentation, and sugar conversion into ethanol.

Photoassisted Degradation of Dye Pollutants. V. Self-Photosensitized Oxidative Transformation of Rhodamine B under Visible Light Irradiation in Aqueous TiO2 Dispersions

Abstract: Chemical oxygen demand (CODCr) and proton NMR, UV−vis, and spin trapping EPR spectroscopic evidence is presented to demonstrate the inverse photosensitized oxidative transformation of tetraethylated rhodamine (RhB) under visible illumination of aqueous titania dispersions. Both de-ethylation and oxidative degradation take place with the former proceeding in a stepwise manner to yield mono-, di-, tri-, and tetra-de-ethylated rhodamine species. Intermediates present after each de-ethylation step remain in a fast dynamic equilibrium between the titania particle surface and the bulk solution. The concentration of •OH radicals, formed from the inverse photosensitization process through the superoxide radical anion, increases upon addition of the anionic dodecylbenzene sulfonate surfactant (DBS) because a larger number of RhB excited states are able to inject an electron into the conduction band of the TiO2 particles. Also, intermediates that can no longer absorb the visible light, (i.e., once the dye solution ...

Exploiting the interparticle electron transfer process in the photocatalysed oxidation of phenol, 2-chlorophenol and pentachlorophenol: chemical evidence for electron and hole transfer between coupled semiconductors

Abstract: The photocatalysed oxidation of phenol, 2-chlorophenol and pentachlorophenol was re-examined under conditions in which TiO2 anatase was sensitized by CdS in air-equilibrated aqueous media; this was to assess whether or not the interparticle electron transfer pathway, first discovered a decade ago (N. Serpone, E. Borgarello and M. Gratzel, J. Chem. Soc., Chem. Commun., (1984) 342) and subsequently applied to enhance reductive processes on titania, could also be applied to photo-oxidative processes. The results indicate that combinations such as CdS/TiO2 lead to an enhanced rate of disappearance of the initial substrate by a factor greater than two, consistent with the notion that (irradiated) CdS electrons are vectorially displaced onto the non-illuminated TiO2 particulates. Cadmium sulphide is a poorer photo-oxidation catalyst than titania. Other semiconductor materials have also been examined under a variety of conditions of pH and irradiation wavelength. The data also show that when both semiconductors in a coupled system are illuminated simultaneously and their valence and conduction bands are suitably disposed, both electron and hole transfer occur (as in the CdS/TiO2, ZnO/TiO2, TiO2/Fe2O3 and ZnO/Fe2O3 couples), which will influence the efficiency of photo-oxidation. N2O-saturated aqueous dispersions of TiO2 have no effect on the photo-oxidation of phenol, although it was expected that nitrous oxide would scavenge the photogenerated electrons in a manner similar to chemisorbed molecular oxygen, and enhance the efficiency. It is suggested that the role of oxygen in photo- oxidations may be more than just a simple electron scavenger.

Photooxidative N-demethylation of methylene blue in aqueous TiO2 dispersions under UV irradiation

Abstract: Methylene blue (MB) is a representative of a class of dyestuffs resistant to biodegradation Its decomposition was examined in aqueous TiO2 dispersions under UV illumination to assess the influence of temperature, pH, concentration of dissolved oxygen (DOC), initial concentration of MB, and light intensity on the kinetics of decomposition Hypsochromic effects (ie blue shifts of spectral bands) resulting from N-demethylation of the dimethylamino group in MB occurs concomitantly with oxidative degradation The maximum quantity of MB adsorbed on TiO2, and the kinetics of degradation of MB and of total organic carbon (TOC) removal were also measured at constant pH 4 Photobleaching of MB solutions takes place at low DOCs and is caused by a reversible reductive process involving photogenerated electrons on TiO2 The rate of degradation of MB remains fairly constant regardless of whether the dispersion was purged with oxygen prior to irradiation or with air during the light irradiation period The photocatalytic process depends on light intensity, but not on the total light energy absorbed The photoreaction followed pseudo-first-order kinetics even at high MB concentrations (03 mM) The temperature dependence of the photodegradation kinetics was assessed (E a =89 kJ/mol ) , as well as the relative photonic efficiency, ξr, relative to phenol (048)