Sadao Matsuzawa

Preparation of a visible light-responsive photocatalyst from a complex of Ti4+ with a nitrogen-containing ligand

An anatase type of TiO2 photocatalyst containing N atoms was synthesized by a new technique using a complex of Ti4+ with a nitrogen-containing ligand as a precursor. The TiO2-like photocatalyst prepared by calcination of a Ti4+–bipyridine complex exhibited high photocatalytic activity for NOx removal under both ultraviolet and visible-light (λ < 645 nm) illumination. The doping of the N atom into the anatase lattice, which is expected from UV-VIS spectroscopy, XRD, and XPS, is inferred as an important factor for the visible light absorption and NOx removal activity under a wide range of visible light illumination. The bipyridine ligand acted as the source of N and C atoms and additionally inhibited sintering of the photocatalyst during heat treatment.

Separation and identification of monomethylated polycyclic aromatic hydrocarbons in heavy oil

Abstract The application of high-performance liquid chromatographic fractionation using a column-switching technique to the identification of monomethylated polycyclic aromatic hydrocarbons by capillary gas chromatography and high-resolution (Shpolskii effect) fluorescence spectroscopy is described. The column-switching technique with silica and aminosilane columns permitted the rapid fractionation of both aromatics and each aromatic ring type in heavy oils. The existence of methylphenanthrenes, methylchrysenes and methylbenz[ a ]anthracenes in Kuwait 340–500/dgC distillate was confirmed by the two methods.

Applicability of low temperature high-resolution fluorescence spectroscopy to the analysis of nitro and amino polycyclic aromatic hydrocarbons

Abstract In order to enable the analysis of nitro and amino polycyclic aromatic hydrocarbon (PAH) isomers in the environment, the applicability of low temperature high-resolution fluorescence spectroscopy (HRFS) using a frozen n -alkane solution (Shpolskii matrix) has been studied. 22 nitro PAHs were treated with potassium borohydride (KBH 4 ) to be reduced into fluorescent amino PAHs, and spectral measurements of reduction products were carried out. Reduction products of 14 nitro PAHs exhibited high-resolution fluorescence spectra. Furthermore, the reproducibility of the reduction reaction and wavelength agreements of the narrow bands in measured spectra were confirmed by comparing spectra obtained at two laboratories in France (the University of Bordeaux I) and Japan (NIRE).

Preparation of Ultrafine TiO2 Nanofibers and their Application in Removal of NOx in Air

Titanium dioxide nanofibers were fabricated by electrospinning technique. The titania solutions were obtained from adding various types of Ti precursor (Ti(OBu)4, Ti(OiPr)4, and Ti(OPr)4) to an ethanol solution containing polyvinyl pyrrolidone (PVP). Acetic acid was used to stabilize the solution and to control the hydrolysis reaction. The porous and well-defined crystalline structure was obtained after calcined at 450oC for 1 h. The thermal behavior, phase composition including crystallite size, as well as the morphology of as-synthesized nanofibers was obtained from thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The average diameter of these nanofibers was in the range from 100 to 400 nm depending on titania precursor. The photocatalytic activity of TiO2 fibers were evaluated for NOx degradation in a gaseous phase. The results demonstrated that at the same catalyst loading, the photocatalytic activity of TiO2 nanofiber was higher than the commercial Degussa P-25.

Photodegradation of some Oxygenated Polycyclic Aromatic Hydrocarbons

Abstract In order to obtain information about the degradability of oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) in environment, photodegradation in acetonitrile solution was studied on 9,10-phenanthrenequinone, 9-phenanthrenecarbaldehyde (phenanthrene-9-carboxaldehyde) and 1,8-naphthalenedicarboxylic anhydride (1,8-naphthalic anhydride), which are formed by fuel combustion or by photoirradiation of PAHs. A solution of the substrate was irradiated under atmospheric conditions using a xenon lamp. Photodegradation rates and information about products were obtained using HPLC with fluorescence and photodiode array detectors and GC/MS. 9,10-Phenanthrenequinone rapidly degraded by irradiation of light and yielded diphenic acid, diphenic acid anhydride, phthalic acid anhydride and some unknown compounds. Diphenic acid was a main product and it was produced at maximum upon 5-hour irradiation when degradation rate approached 100%. This reaction seems not to obey first-order equation. 9-Phenanthrenecarbaldehyde degraded slower than 9,10-phenanthrenequinone and yielded a polar unknown compound as a main product. While 1,8-naphthalenedicarboxylic anhydride showed quite stable character under irradiation of light.

Photochemical Degradation of 1- and 2-methylphenanthrenes in Acetonitrile and on Some Solids

Abstract In order to obtain basic information about photochemical degradability and degradation products for 1- and 2-methylphenanthrenes (MPs), photodegradation of these compounds in an organic solvent (acetonitrile) and on some solids (soil, silica gel [SiO2], and titanium dioxide [TiO2]) were carried out in a laboratory using solar simulators. The results showed that the degradation rate (%) increases in the order of TiO2 > SiO2 > acetonitrile > soil. Products formed in acetonitrile included aromatic compounds with molecular ion [M+] peaks at m/z = 148, 162, 198, 206, 208, 210, 222, 224 and 238. In case of 1 MP, a compound with M+ 206, which was identified as 1-phenanthrene-carbaldehyde, was predominantly formed. However, 2MP showed no predominance for M+ 206 and also yielded M+ 210 and M+ 224 as major products. Degradation on soil and SiO2 gave similar products to those detected in acetonitrile, while that on TiO2 gave different products from the formers. Based on the results of product analysis, three degradation pathways which may occur in acetonitrile are proposed.

High-Resolution Fluorescence Spectra of Cyano Polycyclic Aromatic Hydrocarbons and Their Dependence on Crystal Structures of Solvents

Abstract The effects of the electron withdrawing properties of cyano polycyclic aromatic hydrocarbons (CN-PAH) on the measurements of high-resolution fluorescence spectra with the Shpolskii effect were studied. Cyano-group substituted naphthalenes, anthracenes and phenanthrene were used as the solute, and C5 and C6 n-alkanes and cyclohexane were used as the solvent. In general, microcrystallites of n-alkane prevented interactions between CN-PAH and gave high-resolution spectra at low concentrations. Rigid cyclohexane partly gave high-resolution spectra, but predominantly gave broad emissions from excimers. The effects of cooling and the phase transition of the solvent on fluorescence spectra of CN-PAH were also investigated.

Degradation of VOCs With Pt-TiO

A Parabolic trough concentrator (PTC) and a photocatalytic reactor with Pt-deposited TiO2 Photocatalyst were designed and constructed for the degradation of volatile organic compounds (VOCs). The temperature of photocatalyst coated on the sunlight receiver was easily elevated to around 473 K by PTC, and 79% of toluene or 93% of acetaldehyde was removed continuously, when gaseous toluene (15ppm) or acetaldehyde (400ppm) was passed through the reactor. The combination of sunlight concentrator and Pt-TiO2 catalyst exhibited the enhancement of complete degradation of VOCs, the inhibition of deactivation, and the reactivation of photocatalyst. The contributions of photocatalytic and catalytic activities of Pt-TiO2 were analyzed by using UV lamp and electric heater. Acetaldehyde was thermocatalytically degraded by photodeposited Pt on TiO2 at 343–463 K without UV irradiation, however the UV irradiation was necessary for the complete oxidation of acetaldehyde into CO2 .Copyright

Behavior of Aromatic Electron Donor-Acceptor Pairs in Low Temperature Solvent Matrices

Abstract Some cyano and amino naphthalenes form excimers in low temperature cyclohexane solutions. Effects of the presence of naphthalene molecules in the solution and crystalline state of the solvent on the behavior of these molecules in rigid cyclohexane matrices were studied using low temperature high-resolution fluorescence spectroscopy. In the case of the cyanonaphthalenesnaphthalene systems, an exciplex formation is not clearly observed. However, efficient energy transfer from naphthalene molecules to cyanonaphthalene monomers or aggregates is observed when single crystals of cyclohexane are formed in the matrix. In contrast, a physico-chemical interaction between the electron donor and acceptor molecules (exciplex formation) is observed in the case of the 1-aminonaphthalene-naphthalene system.

Analysis of Olefins in Cracked Oils by High-Performance Liquid Chromatography (Part 1)

水素化分解生成油およびシェールオイルの200°C以上留分中に含まれているオレフィン分および飽和分のHPLCによる定量を目的として, 示差屈折率検出器の検出感度補正で用いる感度係数 (Calibration factor: Area/mg•ml-1) の算出法およびその分析への適用性を検討した。その結果, 試料の比重 (15/4°C) から算出した脂肪族分の示差屈折率 (Δn) を用いて, オレフィンおよび飽和分の感度係数を得ることができる迅速法を確立した。また0.3%硝酸銀含浸シリカカラムを含むアルミナプレカラム分離法に本法で得られた感度係数を適用した分析値は, Mckay 法の改良法による値とよい一致を示した。