Papers by Keyword: Forced Hydrolysis

Abstract: One of the interesting structures in nanoCo₃O₄'s preparation that have been reported fairly recent is the flower-like structure often referred as nanoflower. Several interesting applications involving Co₃O₄ nanoflower have also been reported. This paper present a facile approach to prepare Co₃O₄ nanoflower using one step forced hydrolysis technique using cobalt chloride hexahydrate as starting material as opposed to the standard two steps hydrothermal technique. The produced nanoscale Co₃O₄ is in agglomerate of nanorods producing a dandelion-like flower structure. The prepared Co₃O₄ is in hydrated and amorphous forms with a surface area of 62 m²/g and average pore size of 12 nm.

Abstract: Thermophilic micro-organisms are known to oxidise pyrite and other iron sulphide minerals resulting in the production of acidic ferric sulphate solutions. In this study, the leach liquors generated from such bacterial oxidation were aged through a forced hydrolysis process to yield various iron oxyhydroxides and sulphates. The forced hydrolysis was carried out under a pH range of 1.9 to 9.0. Upon completion of aging, the precipitates generated were characterised using powder X-Ray diffractrometry. The XRD analyses revealed a production of a variety of iron oxyhydroxides and basic iron sulphates. The nature of these precipitates was influenced by the pH conditions used during aging. Jarosite compounds were precipitated under acidic conditions, whilst aging under more basic conditions led to the precipitation of iron oxyhydroxides. These findings may find application in forecasting the phase boundary conditions for Fe(III) precipitation in biogeochemical processes and provide an insight into the tackling of problems associated with the treatment and management of acid mine drainage.

Abstract: The morphology and the capacitive properties of carbon supported hydrous ruthenium oxide (RuOxHy/C), prepared by impregnation of low-surface area carbon black VulcanÒ XC-72 R with solid phase of RuOxHy sol, were investigated by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The oxide sols of different ageing times, prepared by forced hydrolysis of RuCl3, were used for composite preparation. The prepared composites show considerably higher capacitance values in acid electrolyte if compared to carbon black support. Microscopic investigations show that the extent of impregnation and the composite surface appearance depend on ageing time. The composite capacitance increases with ageing time of oxide sol. A gradual decrease in capacitance of thermally untreated composite with charging/discharging cycles was registered, which appears to be related to the extent of impregnation, too. Electrochemical impedance spectroscopy measurements indicate an in-depth capacitance distribution through the composite layer. It was found that NafionÒ layer, used to ensure the adhesion of the composite layer to the current collector, influenced the composite impedance behavior, especially on the oxide-rich parts of the composite surface.