Chromium, especially the hexavalent form, is toxic to humans. Industries like chrome plating, textile, electroplating discharge Cr(VI) in their effiuents. Wastes containing chromium are environmentally persistent and toxic, and cannot be degraded or detoxified biologically. Various techniques developed for the removal of heavy metals include chemical precipitation, ion exchange and adsorption. ...

Several investigations on the extraction of dioxins from soil and fly ash with supercritical fluid have been reported; however, few of them describe the influence of components on the extraction. We extracted dioxins from eight samples with different values of organic carbon content and surface area with supercritical CO(2) at a temperature of 463 K, a pressure of 40 MPa, and using 10% toluene ...

This study evaluated the effect of alumina-blasting and three commercial adhesive primers on the shear bond strength of a dual-cured resin luting agent to zirconia ceramics. Two different-sized zirconia ceramic specimens were treated with or without alumina-blasting and then treated with one of three adhesive primers. Subsequently, specimens were cemented together with Linkmax HV (GC). Half of ...

Infrared spectroscopy is used to follow the chemical changes, as a function of temperature, after sequentially adsorbing trimethylaluminum (TMA) and methanol on hydroxylated alumina. Deuterium-labeled methanol is used to distinguish between the chemistry of methyl and methoxy species. To differentiate between methanol adsorbed on TMA-derived sites and on alumina, the adsorption of methanol is s...

OBJECTIVE To describe bauxite mining and alumina refining processes and to outline the relevant physical, chemical, biological, ergonomic, and psychosocial health risks. METHODS Review article. RESULTS The most important risks relate to noise, ergonomics, trauma, and caustic soda splashes of the skin/eyes. Other risks of note relate to fatigue, heat, and solar ultraviolet and for some opera...

Introduction Nanocrystalline gamma-phase (γ) alumina is among many polytypes of alumina that find extensive applications as a catalyst and catalytic supports. The most useful properties these aluminas provide as catalyst supports are high surface area and welldefined porosity. These properties result primarily from the nano-scale crystalline character of the alumina. The problem is that both th...

A crackand pinhole-free composite membrane consisting of an a-alumina support and a modified y-alumina top layer which is thermally stable up to 1100°C was prepared by the sol-gel method. The supported thermally stable top layer was made by dipcoating the support with a boehmite sol doped with lanthanum nitrate. The temperature effects on the microstructure of the (supported and unsupported) La...

Textural evolution (porosity reduction, pore and crystallite growth) in titania-alumina composite membranes has been studied using thermal analysis, X-ray diffraction, field emission scanning electron microscopy and N, physisorption techniques. The presence of alumina in the membranes improved the thermal stability of the porous texture by retarding the anatase-to-rutile phase transformation a...

Alumina phase loaded with ammonium pyrrolidine dithiocarbamate (APDC )were synthesized based on chemical binding and physical adsorption approaches. The stability of a chemically modified APDC especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of alumina immobilized APDC phase. The application of this alumina for sorpti...

To know the electrical properties of any materials is very important for practical application of that material. In this paper I have tried to find out the proper electrical properties of Indium doped Alumina (Al2O3) for practical application of this Alumina. For this purpose all thin films are deposited on glass substrate by electron beam evaporation technique at a pressure of about 1.5 x 10-6...