Hirofumi Hinode

Photocatalytic decomposition of perfluorooctanoic acid by iron and niobium co-doped titanium dioxide.

The photocatalytic decomposition of perfluorooctanoic acid (PFOA) in aqueous solution using Fe and Nb co-doped TiO(2) (Fe:Nb-TiO(2)) prepared by sol-gel method was investigated. The photocatalytic activity of Fe:Nb-TiO(2) towards PFOA degradation was compared to that of pure TiO(2) synthesized using the same method, and that of the commercially available TiO(2) photocatalyst, Aeroxide TiO(2) P25 (AO-TiO(2) P25). The photocatalysts were characterized by XRD, DRS, BET-N(2) adsorption isotherm, and SEM-EDX techniques and the data were correlated to the photocatalytic activity. Fe:Nb-TiO(2) showed the highest activity compared to the undoped TiO(2) and the commercially available TiO(2). Such activity was attributable to the effects of co-doping both on the physico-chemical properties and surface interfacial charge transfer mechanisms. Perfluorocarboxylic acids (PFCAs) with shorter carbon chain length and fluoride ions were identified as photocatalytic reaction intermediates and products.

Effects of N-acetylation degree on N-acetylated chitosan hydrolysis with commercially available and modified pectinases

Three types of N-acetylated chitosans (NACs) with different degrees of acetylation (DA) were prepared and used as a substrate for enzymatic hydrolysis with a commercially available pectinase and a modified one. Pectinase modification was conducted using polyalkyleneoxide-maleic anhydride copolymer (PEO-MA copolymer). The effects of DA on enzymatic reaction with native and modified pectinases were investigated experimentally. Initial hydrolysis rate and Michaelis-Menten kinetic parameters were measured by analysis of reducing sugars. DA of NAC strongly affected the hydrolytic characteristics of native and modified pectinases. N-acetylation of chitosan increased the initial hydrolysis rate and the enzyme-substrate affinity with respect to both pectinases: NACs with DA over 0.3 showed high initial hydrolysis rate and strong affinity between enzyme and substrate. Especially, when NAC with DA over 0.3 was treated with modified pectinase, the affinity became much stronger than the native pectinase.

A study of the decomposition of neodymium hydroxy carbonate and neodymium carbonate hydrate

Abstract Comprehensive studies of the decomposition of (NdOH)CO3 and Nd2(CO3)3 · 8H2O have been carried out. The atomic level details of the decomposition as revealed by high-resolution electron microscopy are correlated with the results from thermogravimetric analysis and high-temperature X-ray diffraction analysis. The two sequences of decomposition are found to be (NdOH)Co 3 → (NdO) 2 CO 3 −I + (NdO) 3 Co 3 −II → (NdO) 2 CO 3 −II → (NdO) 2 Co 3 −II + Nd 2 O 3 −A → Nd 2 O 3 −A + Nd 2 O 3 −C → Nd 2 O 3 −A and Nd 2 (CO 3 ) 3 · 8H 2 O → Nd 2 (CO 3 ) 3 · H 2 O → Nd 2 (CO 3 ) 3 → (NdO) 2 CO 3 −I → (NdO) 2 CO 3 −I + (NdO) 2 CO 3 −II → (NdO) 2 CO 3 −II + (NdO) 2 CO 3 −I + Nd 2 O 3 −C → Nd 2 O 3 −A + Nd 2 O 3 −C .

Permeation and separation of styrene/ethylbenzene mixtures through cross-linked poly(hexamethylene sebacate) membranes

Abstract Poly(hexamethylene sebacate) (PHS) which has strong affinity for styrene was selected as membrane material, and the characteristics of permeation and separation for the styrene/ethylbenzene mixtures through these PHS cross-linked with N , N , N ′, N ′-tetraglycidyl m -xylenediamine(TETRA-DX) membrane by pervaporation were investigated. The cross-linked PHS membranes exhibited a styrene permselectivity for the styrene/ethylbenzene mixtures and the permeation rate increased with increasing styrene in the feed solution. The permselectivity of their membranes was strongly governed by the sorption separation process depending on the difference of the solubility between styrene and ethylbenzene. The molecular weight of PHS had also influence to the separation factor and permeation rate in pervaporation.

Catalytic reduction of nitric monoxide by ethene over Ag/TiO2 in the presence of excess oxygen

Selective reduction of nitric oxide (NO) by ethene in the presence of excess oxygen was investigated using a silver supported on TiO2 (Ag/TiO2) catalyst. Ag/TiO2 showed high catalytic activity for the reduction of NO to N2 and N2O. The activity for the reduction of NO to N2 and N2O was enhanced with an increase up to 3 wt.% Ag loading level. On increasing the concentration of ethene, the catalytic activity for the reduction of NO to N2 and N2O was enhanced. The reduction of NO over Ag/TiO2 catalyst never proceeds without coexistent oxygen.

Catalytic oxidation of no to NO2 over Cr/TiO2 and Cu/TiO2 under oxidizing atmosphere

The catalytic activity of Cr/TiO2 and Cu/TiO2 for the oxidation of NO under an oxidizing atmosphere has been examined. Both catalysts had excellent ability for the oxidation of NO to NO2 in the temperature range of 350–400°C.

Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC), which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1) their technical properties are comparable if not better; (2) they can be produced from industrial wastes; and (3) within reasonable constraints, their production requires less energy and emits significantly less CO2. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC) use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA) and coal bottom ash (CBA), and rice hull ash (RHA). The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF) for elemental and X-ray diffraction (XRD) for mineralogical composition. The raw materials’ thermal stability and loss on ignition (LOI) were determined using thermogravimetric analysis (TGA) and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP) analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Using a Scheffé-based mixture design, targeting applications with low thermal conductivity, light weight and moderate strength and allowing for a maximum of five percent by mass of rice hull ash in consideration of the waste utilization of all three components, it has been determined that an 85-10-5 by weight ratio of CFA-CBA-RHA activated with 80-20 by mass ratio of 12 M NaOH and sodium silicate (55% H2O, modulus = 3) produced geopolymers with a compressive strength of 18.5 MPa, a volumetric weight of 1660 kg/m3 and a thermal conductivity of 0.457 W/m-°C at 28-day curing when pre-cured at 80 °C for 24 h. For this study, the estimates of embodied energy and CO2 were all below 1.7 MJ/kg and 0.12 kg CO2/kg, respectively.

Sol–gel hydrothermal synthesis of microstructured CaO-based adsorbents for CO2 capture

In this study, microstructured CaO-based adsorbents were synthesized by a sol–gel hydrothermal method using calcium nitrate tetrahydrate, citric acid and sodium hydroxide as precursors. Experiments with different NaOH concentrations (2, 6 and 10 M) were carried out to investigate the effects on the morphologies and CO2 adsorption activities of the synthesized adsorbents. X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) results showed that different NaOH concentrations resulted in different crystal phases and morphologies. A novel three-dimensional (3D) hierarchical calcite (CaCO3) hollow microspherical adsorbent composed of one-dimensional (1D) spike-shaped nanorods was obtained with 2 M NaOH. XRD analyses confirmed that the hierarchical CaCO3 hollow microspheres were characteristic of the calcite phase. The FESEM image revealed that the microspheres were composed of 1D spike-shaped nanorods with an average length of 500 nm. The cross-sectional FESEM image showed that the microspheres had hollow structures with an average inner cavity of 2 μm and a shell thickness of approximately 0.5 μm. The CO2 adsorption performance of the synthesized adsorbents was investigated using thermogravimetry-differential thermal analysis (TG-DTA) apparatus. The results indicated that the novel hierarchical calcite (CaCO3) hollow microspherical adsorbent composed of one-dimensional (1D) spike-shaped nanorods possessed higher carbonation conversion of 45% after 15 cycles, which was about 22% higher than that of other adsorbents synthesized with 6 and 10 M NaOH concentration and limestone. This property could be attributed to the 3D hierarchical hollow microsphere structure, 1D spike-shaped nanorod structure, trimodal pore size distribution and large BET surface area (44.85 m2 g−1) of the novel adsorbent.

Preparation of LiTiS intercalation compound by a solid state process

Abstract Lithium titanium sulfides Li x Ti 1 + y S 2 were prepared by reacting mixtures of Li 2 CO 3 and TiS 2 with pure hydrogen sulfide. A homogeneous region with CdI 2 type TiS 2 crystal structure was observed in the range, 0 x Ti 1 + y S 2 prepared in this study contained some extra titanium ions in the van der Waals gaps of TiS 2 , the observed lattice parameters and the open circuit voltages (OCV) were very similar to those reported for Li x TiS 2 prepared by using stoichiometric TiS 2 in the literature. An anomaly was observed at the composition of x + y ⋍ 1 3 in the compositional variations of lattice parameters and that of OCV, which would show the ordering of lithium and titanium ions in the partially filled metal layer of Li x Ti 1 + y S 2 . The electrical conductivity of sintered pellets of Li 0.353 Ti 1.044 S 2 was 1.1×10 3 S cm −1 at room temperature which was higher than that of binary titanium sulfide, Ti 1.049 S 2 ( ⋍4.0×10 2 S cm −1 ).

Phase equilibria of the VS-V5S8 system from 923 to 1323 K

Sulfur partial pressure-isotherms at temperatures from 923 to 1323 K were obtained over a wide range of compositions of VS-V5S8 by combining results from the phase equilibria of the VS-V3S4 system in the present study and those from previously reported ones for the V3S4-V5S8 system at temperatures from 923 to 1173 K. The phase equilibria of VS-V3S4 were determined for the composition range from VS1.08 to VS1.333 by the quenching method under controlled partial pressure of sulfur in the range from 1014 to 10−3 atm (1 atm = 101.3 kPa) at temperatures from 1023 to 1323 K. Three vanadium sulfides were observed for this composition range in agreement with results reported in the literature,i.e. orthorhombic VS, hexagonal VS, and V3S4. The quenched V3S4 phase with nonstoichiometric composition extended over both metal-rich and sulfur-rich regions of the plateau, supposedly representing a two phase region, observed on each Ps2-composition isotherm. This anomalous phase relation was discussed along with the profiles of the isotherms. The partial molar enthalpies of sulfur in the nonstoichiometric hexagonal VS and V3S4 regions were calculated from the isotherms. Their values ranged from −46 to −56 kcal/g-at. (from −190 to −240 kJ/g-at.) and decreased with increasing deviation from stoichiometry.