CO hydrogenation catalyzed by alumina-supported osmium: Particle size effects

Alumina-supported catalysts were prepared by conventional aqueous impregnation with [H2OsCl6] and by reaction of organoosmium clusters {[Os3(CO)12], [H4Os4(CO)12], and [Os6(CO)18]} with the support. The catalysts were tested for CO hydrogenation at 250-325 [deg]C and 10 atm, the products being Schulz-Flory distributions of hydrocarbons with small yields of dimethyl ether. The fresh and used catalysts were characterized by infrared spectroscopy and high-resolution transmission electron microscopy. The catalyst prepared from [H2OsCl6] had larger particles of Os (~70 A). The cluster-derived catalysts initially consisted of molecular clusters on the support; the used catalysts contained small Os aggregates (typically 10-20 A in diameter). The catalytic activity for hydrocarbon formation increased with increasing Os aggregate size, but the activity for dimethyl ether formation was almost independent of aggregate size. The hydrocarbon synthesis was evidently catalyzed by the Os aggregates, and the ether synthesis was perhaps catalyzed by mononuclear Os Complexes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25555/1/0000097.pd

A novel zerovalent manganese for removal of copper ions: synthesis, characterization and adsorption studies

Synthesis of nanoscale zerovalent manganese (nZVMn) by chemical reduction was carried out in a single pot system under inert environment. nZVMn was charac�terized using a combination of analytical techniques: Ultraviolet–Visible Spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray, BET surface area and Point of Zero Charge. The adsorption physicochemical factors: pH, contact time, adsorbent dose, agitation speed, initial copper ion concen�tration and temperature were optimized. The kinetic data fitted better to Pseudo second-order, Elovich, fractional power and intraparticle diffusion models and their validity was tested by three statistical models: sum of square error, Chi-square (v2 ) and normalized standard deviation (Dq). Seven of the two-parameter isotherm models [Freundlich, Langmuir, Temkin, Dubinin–Kaganer–Raduskevich (DKR), Halsey, Harkin–Jura and Flory–Huggins] were used to analyse the equilibrium adsorption data. The Langmuir monolayer adsorption capacity (Qmax = 181.818 mg/g) obtained is greater than other those of nano-adsorbents utilized in adsorption of copper ions. The equilibrium adsorption data were better described by Langmuir, Fre�undlich, Temkin, DKR and Halsey isotherm models con�sidering their coefficient of regression (R2[0.90). The values of the thermodynamic parameters: standard enthalpy change DH� (?50.27848 kJ mol-1 ), standard entropy change DS� (203.5724 J mol-1 K-1 ) and the Gibbs free energy change DG� revealed that the adsorption process was feasible, spontaneous, and endothermic in nature. The performance of this novel nanoscale zerovalent manganese (nZVMn) suggested that it has a great potential for effective removal of copper ions from aqueous solutio

Kinetics and Thermodynamics of Bleaching Process in Aqueous Solution using Sodium Hypochlorite

The kinetics of bleaching process of oxidation of typical dye with a bleaching agent - sodium hypochlorite in aqueous medium was studied. The kinetic runs were executed using spectrophotometer to changes in concentration under pseudo first order whereby concentration of NaOCl was in large excess compared with the   concentration of dye. The factors affecting the reaction rate that were studied include the concentration of dye and oxidant, temperature, ionic strength and pH of the bleaching reaction medium and the presence of a variable valence metal ion The result shows that the rate of oxidation increases with increasing in temperature, ionic strength and pH. Increasing in substrate and oxidant concentrations also increase the rate of oxidation. Higher observed rate constant k1   was obtained in the presence of Fe(III)ion. The Arrhenius activation energy for the oxidation in the absence and presence of Fe(III)ion are 56.21 kJmol-1 and 51.21 kJmol-1 respectively.  The result of thermodynamic parameters such as the lowering of activation energy (Ea) and the higher value of second rate constants k2 in the presence of Fe (III) ion provide further support for Fe (III) ion enhancement of rate of oxidation. &nbsp

Cleaner energy through liquefaction of Cocoa (Theobroma cacao) pod husk: Pretreatment and process optimization

The kinetics and isotherm modeling of adsorption of Rhodamine B (RhB) Dye onto chitosan supported zerovalent iron nanocomposite (C-nZVI) was successfully studied in a batch technique. The quantity adsorbed increased with increase in initial concentration from 49.33 mg – 242.37 mg for 200 ppm to 1000 ppm and high percentage removal efficiency (%RE) of 99.72% attained at 90 minutes contact time. Equilibrium data were analyzed by six isotherm models: Langmuir, Freundlich, Temkin, Dubinin-Kaganer-Raduskevich (DKR), Redlich-peterson and Halsey isotherm model. Equilibrium data best fitted to Freundlich isotherm supported by Halsey isotherm model. Langmuir monolayer adsorption capacity (256.41 mg/g) of C-nZVI obtained greater than most adsorbent reported for adsorption of RhB. The mean adsorption free energy, E per molecule evaluated from DKR model was less than 8 KJmol-1 indicating a physisorption mechanism. The kinetic data best fitted to pseudo second-order kinetic model as validated by sum of square error (SSE) statistical model and the mechanism controlled by pore diffusion. The study revealed the great potential of C-nZVI for effective removal of RhB dye. C-nZVI is therefore recommended for civic and industrial effluents treatment

Telemedicine’s potential to support good dying in Nigeria: a qualitative study

Objectives This qualitative study explores Nigerian health care professionals’ concepts of good dying/a good death and how telemedicine technologies and services would fit the current Nigerian palliative care practice. Materials and Methods Supported by the Centre for Palliative Care Nigeria (CPCN) and the University College Hospital (UCH) in Ibadan, Nigeria, the authors organized three focus groups with Nigerian health care professionals interested in palliative care, unstructured interviews with key role players for palliative care and representatives of telecom companies, and field visits to primary, secondary and tertiary healthcare clinics that provided palliative care. Data analysis consisted of open coding, constant comparison, diagramming of categorizations and relations, and extensive member checks. Results The focus group participants classified good dying into 2 domains: a feeling of completion of the individual life and dying within the community. Reported barriers to palliative care provision were socio-economic consequences of being seriously ill, taboos on dying and being ill, restricted access to adequate medical-technical care, equation of religion with medicine, and the faulty implementation of palliative care policy by government. The addition of telemedicine to Nigeria’s palliative care practice appears problematic, due to irregular bandwidth, poor network coverage, and unstable power supply obstructing interactivity and access to information. However, a tele-education ‘lite’ scenario seemed viable in Nigeria, wherein low-tech educational networks are central that build on non-synchronous online communication. Discussion Nigerian health care professionals’ concepts on good dying/a good death and barriers and opportunities for palliative care provision were, for the greater part, similar to prior findings from other studies in Africa. Information for and education of patient, family, and community are essential to further improve palliative care in Africa. Telemedicine can only help if low-tech solutions are applied that work around network coverage problems by focusing on non-synchronous online communication

The Ratios of Vanadium-to-nickel and Phenanthrene-to-dibenzothiophene as Means of Identifying Petroleum Source and Classification of Nigeria Crude Oils

<div><p>Nigeria light, medium, and heavy crude oils were categorized based on the ratio of vanadium-to-nickel (V/Ni) and the ratio of phenanthrene-to-dibenzothiophene (PHEN/DBT) derivatives. V/Ni ratio of 0.47, 1.36, and 2.77 were observed for light, medium, and heavy crude oils, respectively, while the PHEN/DBT ratio was observed to be 8.35, 4.33, and 1.09 for the light, medium, and heavy crude oils, respectively. From the results obtained, light crude oil was suggested to originate from marine organic matter while the heavy oil originates from the terrestrial organic matter.</p></div